Merge LLVM 7.0.1 release.

With fixes from mortimer@ (thanks!)
Tested by many, especially naddy@ (thanks!)

14 files changed, 3560 insertions, 2031 deletions

diff --git a/gnu/llvm/tools/lld/ELF/Config.h b/gnu/llvm/tools/lld/ELF/Config.h
index c7b58cf5b86..81c141ca011 100644
--- a/gnu/llvm/tools/lld/ELF/Config.h
+++ b/gnu/llvm/tools/lld/ELF/Config.h
@@ -10,6 +10,7 @@
 #ifndef LLD_ELF_CONFIG_H
 #define LLD_ELF_CONFIG_H
 
+#include "lld/Common/ErrorHandler.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSet.h"
@@ -17,13 +18,13 @@
 #include "llvm/Support/CachePruning.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Support/Endian.h"
-
 #include <vector>
 
 namespace lld {
 namespace elf {
 
 class InputFile;
+class InputSectionBase;
 
 enum ELFKind {
   ELFNoneKind,
@@ -39,6 +40,9 @@ enum class BuildIdKind { None, Fast, Md5, Sha1, Hexstring, Uuid };
 // For --discard-{all,locals,none}.
 enum class DiscardPolicy { Default, All, Locals, None };
 
+// For --icf={none,safe,all}.
+enum class ICFLevel { None, Safe, All };
+
 // For --strip-{all,debug}.
 enum class StripPolicy { None, All, Debug };
 
@@ -54,6 +58,9 @@ enum class SortSectionPolicy { Default, None, Alignment, Name, Priority };
 // For --target2
 enum class Target2Policy { Abs, Rel, GotRel };
 
+// For tracking ARM Float Argument PCS
+enum class ARMVFPArgKind { Default, Base, VFP, ToolChain };
+
 struct SymbolVersion {
   llvm::StringRef Name;
   bool IsExternCpp;
@@ -79,21 +86,27 @@ struct Configuration {
   llvm::StringMap<uint64_t> SectionStartMap;
   llvm::StringRef Chroot;
   llvm::StringRef DynamicLinker;
+  llvm::StringRef DwoDir;
   llvm::StringRef Entry;
   llvm::StringRef Emulation;
   llvm::StringRef Fini;
   llvm::StringRef Init;
   llvm::StringRef LTOAAPipeline;
   llvm::StringRef LTONewPmPasses;
+  llvm::StringRef LTOObjPath;
+  llvm::StringRef LTOSampleProfile;
   llvm::StringRef MapFile;
   llvm::StringRef OutputFile;
   llvm::StringRef OptRemarksFilename;
+  llvm::StringRef ProgName;
   llvm::StringRef SoName;
   llvm::StringRef Sysroot;
   llvm::StringRef ThinLTOCacheDir;
+  llvm::StringRef ThinLTOIndexOnlyArg;
+  std::pair<llvm::StringRef, llvm::StringRef> ThinLTOObjectSuffixReplace;
+  std::pair<llvm::StringRef, llvm::StringRef> ThinLTOPrefixReplace;
   std::string Rpath;
   std::vector<VersionDefinition> VersionDefinitions;
-  std::vector<llvm::StringRef> Argv;
   std::vector<llvm::StringRef> AuxiliaryList;
   std::vector<llvm::StringRef> FilterList;
   std::vector<llvm::StringRef> SearchPaths;
@@ -103,34 +116,41 @@ struct Configuration {
   std::vector<SymbolVersion> VersionScriptGlobals;
   std::vector<SymbolVersion> VersionScriptLocals;
   std::vector<uint8_t> BuildIdVector;
+  llvm::MapVector<std::pair<const InputSectionBase *, const InputSectionBase *>,
+                  uint64_t>
+      CallGraphProfile;
   bool AllowMultipleDefinition;
-  bool AndroidPackDynRelocs = false;
+  bool AndroidPackDynRelocs;
   bool ARMHasBlx = false;
   bool ARMHasMovtMovw = false;
   bool ARMJ1J2BranchEncoding = false;
   bool AsNeeded = false;
   bool Bsymbolic;
   bool BsymbolicFunctions;
+  bool CheckSections;
   bool CompressDebugSections;
+  bool Cref;
   bool DefineCommon;
   bool Demangle = true;
   bool DisableVerify;
   bool EhFrameHdr;
   bool EmitRelocs;
   bool EnableNewDtags;
+  bool ExecuteOnly;
   bool ExportDynamic;
   bool FixCortexA53Errata843419;
   bool GcSections;
   bool GdbIndex;
   bool GnuHash = false;
+  bool GnuUnique;
   bool HasDynamicList = false;
   bool HasDynSymTab;
-  bool ICF;
-  bool ICFData;
+  bool IgnoreDataAddressEquality;
+  bool IgnoreFunctionAddressEquality;
+  bool LTODebugPassManager;
+  bool LTONewPassManager;
   bool MergeArmExidx;
   bool MipsN32Abi = false;
-  bool NoGnuUnique;
-  bool NoUndefinedVersion;
   bool NoinhibitExec;
   bool Nostdlib;
   bool OFormatBinary;
@@ -138,7 +158,9 @@ struct Configuration {
   bool OptRemarksWithHotness;
   bool Pie;
   bool PrintGcSections;
+  bool PrintIcfSections;
   bool Relocatable;
+  bool RelrPackDynRelocs;
   bool SaveTemps;
   bool SingleRoRx;
   bool Shared;
@@ -146,13 +168,22 @@ struct Configuration {
   bool SysvHash = false;
   bool Target1Rel;
   bool Trace;
-  bool Verbose;
+  bool ThinLTOEmitImportsFiles;
+  bool ThinLTOIndexOnly;
+  bool UndefinedVersion;
+  bool UseAndroidRelrTags = false;
+  bool WarnBackrefs;
   bool WarnCommon;
   bool WarnMissingEntry;
+  bool WarnSymbolOrdering;
+  bool WriteAddends;
   bool ZCombreloc;
+  bool ZCopyreloc;
   bool ZExecstack;
+  bool ZHazardplt;
   bool ZInitfirst;
-  bool ZNocopyreloc;
+  bool ZInterpose;
+  bool ZKeepTextSectionPrefix;
   bool ZNodelete;
   bool ZNodlopen;
   bool ZNow;
@@ -161,20 +192,22 @@ struct Configuration {
   bool ZRodynamic;
   bool ZText;
   bool ZRetpolineplt;
-  bool ExitEarly;
   bool ZWxneeded;
   DiscardPolicy Discard;
+  ICFLevel ICF;
   OrphanHandlingPolicy OrphanHandling;
   SortSectionPolicy SortSection;
   StripPolicy Strip;
   UnresolvedPolicy UnresolvedSymbols;
   Target2Policy Target2;
+  ARMVFPArgKind ARMVFPArgs = ARMVFPArgKind::Default;
   BuildIdKind BuildId = BuildIdKind::None;
   ELFKind EKind = ELFNoneKind;
   uint16_t DefaultSymbolVersion = llvm::ELF::VER_NDX_GLOBAL;
   uint16_t EMachine = llvm::ELF::EM_NONE;
   llvm::Optional<uint64_t> ImageBase;
   uint64_t MaxPageSize;
+  uint64_t MipsGotSize;
   uint64_t ZStackSize;
   unsigned LTOPartitions;
   unsigned LTOO;
@@ -240,6 +273,12 @@ struct Configuration {
 // The only instance of Configuration struct.
 extern Configuration *Config;
 
+static inline void errorOrWarn(const Twine &Msg) {
+  if (!Config->NoinhibitExec)
+    error(Msg);
+  else
+    warn(Msg);
+}
 } // namespace elf
 } // namespace lld
 
diff --git a/gnu/llvm/tools/lld/ELF/Driver.cpp b/gnu/llvm/tools/lld/ELF/Driver.cpp
index 602c72058c4..5d8e5d84a37 100644
--- a/gnu/llvm/tools/lld/ELF/Driver.cpp
+++ b/gnu/llvm/tools/lld/ELF/Driver.cpp
@@ -30,9 +30,9 @@
 #include "InputFiles.h"
 #include "InputSection.h"
 #include "LinkerScript.h"
+#include "MarkLive.h"
 #include "OutputSections.h"
 #include "ScriptParser.h"
-#include "Strings.h"
 #include "SymbolTable.h"
 #include "Symbols.h"
 #include "SyntheticSections.h"
@@ -42,12 +42,16 @@
 #include "lld/Common/Driver.h"
 #include "lld/Common/ErrorHandler.h"
 #include "lld/Common/Memory.h"
+#include "lld/Common/Strings.h"
+#include "lld/Common/TargetOptionsCommandFlags.h"
 #include "lld/Common/Threads.h"
 #include "lld/Common/Version.h"
+#include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compression.h"
+#include "llvm/Support/LEB128.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/TarWriter.h"
 #include "llvm/Support/TargetSelect.h"
@@ -66,16 +70,18 @@ using namespace lld::elf;
 Configuration *elf::Config;
 LinkerDriver *elf::Driver;
 
-static void setConfigs();
+static void setConfigs(opt::InputArgList &Args);
 
 bool elf::link(ArrayRef<const char *> Args, bool CanExitEarly,
                raw_ostream &Error) {
-  errorHandler().LogName = Args[0];
+  errorHandler().LogName = sys::path::filename(Args[0]);
   errorHandler().ErrorLimitExceededMsg =
       "too many errors emitted, stopping now (use "
       "-error-limit=0 to see all errors)";
   errorHandler().ErrorOS = &Error;
+  errorHandler().ExitEarly = CanExitEarly;
   errorHandler().ColorDiagnostics = Error.has_colors();
+
   InputSections.clear();
   OutputSections.clear();
   Tar = nullptr;
@@ -88,14 +94,14 @@ bool elf::link(ArrayRef<const char *> Args, bool CanExitEarly,
   Driver = make<LinkerDriver>();
   Script = make<LinkerScript>();
   Symtab = make<SymbolTable>();
-  Config->Argv = {Args.begin(), Args.end()};
+  Config->ProgName = Args[0];
 
-  Driver->main(Args, CanExitEarly);
+  Driver->main(Args);
 
   // Exit immediately if we don't need to return to the caller.
   // This saves time because the overhead of calling destructors
   // for all globally-allocated objects is not negligible.
-  if (Config->ExitEarly)
+  if (CanExitEarly)
     exitLld(errorCount() ? 1 : 0);
 
   freeArena();
@@ -113,7 +119,8 @@ static std::tuple<ELFKind, uint16_t, uint8_t> parseEmulation(StringRef Emul) {
 
   std::pair<ELFKind, uint16_t> Ret =
       StringSwitch<std::pair<ELFKind, uint16_t>>(S)
-          .Cases("aarch64elf", "aarch64linux", {ELF64LEKind, EM_AARCH64})
+          .Cases("aarch64elf", "aarch64linux", "aarch64_elf64_le_vec",
+                 {ELF64LEKind, EM_AARCH64})
           .Cases("armelf", "armelf_linux_eabi", {ELF32LEKind, EM_ARM})
           .Case("elf32_x86_64", {ELF32LEKind, EM_X86_64})
           .Cases("elf32btsmip", "elf32btsmipn32", {ELF32BEKind, EM_MIPS})
@@ -122,6 +129,7 @@ static std::tuple<ELFKind, uint16_t, uint8_t> parseEmulation(StringRef Emul) {
           .Case("elf64btsmip", {ELF64BEKind, EM_MIPS})
           .Case("elf64ltsmip", {ELF64LEKind, EM_MIPS})
           .Case("elf64ppc", {ELF64BEKind, EM_PPC64})
+          .Case("elf64lppc", {ELF64LEKind, EM_PPC64})
           .Cases("elf_amd64", "elf_x86_64", {ELF64LEKind, EM_X86_64})
           .Case("elf_i386", {ELF32LEKind, EM_386})
           .Case("elf_iamcu", {ELF32LEKind, EM_IAMCU})
@@ -228,11 +236,15 @@ void LinkerDriver::addFile(StringRef Path, bool WithLOption) {
     Files.push_back(
         createSharedFile(MBRef, WithLOption ? path::filename(Path) : Path));
     return;
-  default:
+  case file_magic::bitcode:
+  case file_magic::elf_relocatable:
     if (InLib)
       Files.push_back(make<LazyObjFile>(MBRef, "", 0));
     else
       Files.push_back(createObjectFile(MBRef));
+    break;
+  default:
+    error(Path + ": unknown file type");
   }
 }
 
@@ -248,18 +260,11 @@ void LinkerDriver::addLibrary(StringRef Name) {
 // LTO calls LLVM functions to compile bitcode files to native code.
 // Technically this can be delayed until we read bitcode files, but
 // we don't bother to do lazily because the initialization is fast.
-static void initLLVM(opt::InputArgList &Args) {
+static void initLLVM() {
   InitializeAllTargets();
   InitializeAllTargetMCs();
   InitializeAllAsmPrinters();
   InitializeAllAsmParsers();
-
-  // Parse and evaluate -mllvm options.
-  std::vector<const char *> V;
-  V.push_back("lld (LLVM option parsing)");
-  for (auto *Arg : Args.filtered(OPT_mllvm))
-    V.push_back(Arg->getValue());
-  cl::ParseCommandLineOptions(V.size(), V.data());
 }
 
 // Some command line options or some combinations of them are not allowed.
@@ -290,11 +295,21 @@ static void checkOptions(opt::InputArgList &Args) {
       error("-r and -shared may not be used together");
     if (Config->GcSections)
       error("-r and --gc-sections may not be used together");
-    if (Config->ICF)
+    if (Config->GdbIndex)
+      error("-r and --gdb-index may not be used together");
+    if (Config->ICF != ICFLevel::None)
       error("-r and --icf may not be used together");
     if (Config->Pie)
       error("-r and -pie may not be used together");
   }
+
+  if (Config->ExecuteOnly) {
+    if (Config->EMachine != EM_AARCH64)
+      error("-execute-only is only supported on AArch64 targets");
+
+    if (Config->SingleRoRx && !Script->HasSectionsCommand)
+      error("-execute-only and -no-rosegment cannot be used together");
+  }
 }
 
 static const char *getReproduceOption(opt::InputArgList &Args) {
@@ -310,7 +325,38 @@ static bool hasZOption(opt::InputArgList &Args, StringRef Key) {
   return false;
 }
 
-void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
+static bool getZFlag(opt::InputArgList &Args, StringRef K1, StringRef K2,
+                     bool Default) {
+  for (auto *Arg : Args.filtered_reverse(OPT_z)) {
+    if (K1 == Arg->getValue())
+      return true;
+    if (K2 == Arg->getValue())
+      return false;
+  }
+  return Default;
+}
+
+static bool isKnown(StringRef S) {
+  return S == "combreloc" || S == "copyreloc" || S == "defs" ||
+         S == "execstack" || S == "hazardplt" || S == "initfirst" ||
+         S == "interpose" ||
+         S == "keep-text-section-prefix" || S == "lazy" || S == "muldefs" ||
+         S == "nocombreloc" || S == "nocopyreloc" || S == "nodelete" ||
+         S == "nodlopen" || S == "noexecstack" ||
+         S == "nokeep-text-section-prefix" || S == "norelro" || S == "notext" ||
+         S == "now" || S == "origin" || S == "relro" || S == "retpolineplt" ||
+         S == "rodynamic" || S == "text" || S == "wxneeded" ||
+         S.startswith("max-page-size=") || S.startswith("stack-size=");
+}
+
+// Report an error for an unknown -z option.
+static void checkZOptions(opt::InputArgList &Args) {
+  for (auto *Arg : Args.filtered(OPT_z))
+    if (!isKnown(Arg->getValue()))
+      error("unknown -z value: " + StringRef(Arg->getValue()));
+}
+
+void LinkerDriver::main(ArrayRef<const char *> ArgsArr) {
   ELFOptTable Parser;
   opt::InputArgList Args = Parser.parse(ArgsArr.slice(1));
 
@@ -319,7 +365,7 @@ void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
 
   // Handle -help
   if (Args.hasArg(OPT_help)) {
-    printHelp(ArgsArr[0]);
+    printHelp();
     return;
   }
 
@@ -348,9 +394,6 @@ void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
   if (Args.hasArg(OPT_version))
     return;
 
-  Config->ExitEarly = CanExitEarly && !Args.hasArg(OPT_full_shutdown);
-  errorHandler().ExitEarly = Config->ExitEarly;
-
   if (const char *Path = getReproduceOption(Args)) {
     // Note that --reproduce is a debug option so you can ignore it
     // if you are trying to understand the whole picture of the code.
@@ -368,10 +411,14 @@ void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
   }
 
   readConfigs(Args);
-  initLLVM(Args);
+  checkZOptions(Args);
+  initLLVM();
   createFiles(Args);
+  if (errorCount())
+    return;
+
   inferMachineType();
-  setConfigs();
+  setConfigs(Args);
   checkOptions(Args);
   if (errorCount())
     return;
@@ -455,6 +502,8 @@ static bool isOutputFormatBinary(opt::InputArgList &Args) {
     StringRef S = Arg->getValue();
     if (S == "binary")
       return true;
+    if (S.startswith("elf"))
+      return false;
     error("unknown --oformat value: " + S);
   }
   return false;
@@ -482,6 +531,15 @@ static StringRef getDynamicLinker(opt::InputArgList &Args) {
   return Arg->getValue();
 }
 
+static ICFLevel getICF(opt::InputArgList &Args) {
+  auto *Arg = Args.getLastArg(OPT_icf_none, OPT_icf_safe, OPT_icf_all);
+  if (!Arg || Arg->getOption().getID() == OPT_icf_none)
+    return ICFLevel::None;
+  if (Arg->getOption().getID() == OPT_icf_safe)
+    return ICFLevel::Safe;
+  return ICFLevel::All;
+}
+
 static StripPolicy getStrip(opt::InputArgList &Args) {
   if (Args.hasArg(OPT_relocatable))
     return StripPolicy::None;
@@ -556,6 +614,8 @@ getBuildId(opt::InputArgList &Args) {
     return {BuildIdKind::Fast, {}};
 
   StringRef S = Arg->getValue();
+  if (S == "fast")
+    return {BuildIdKind::Fast, {}};
   if (S == "md5")
     return {BuildIdKind::Md5, {}};
   if (S == "sha1" || S == "tree")
@@ -570,6 +630,57 @@ getBuildId(opt::InputArgList &Args) {
   return {BuildIdKind::None, {}};
 }
 
+static std::pair<bool, bool> getPackDynRelocs(opt::InputArgList &Args) {
+  StringRef S = Args.getLastArgValue(OPT_pack_dyn_relocs, "none");
+  if (S == "android")
+    return {true, false};
+  if (S == "relr")
+    return {false, true};
+  if (S == "android+relr")
+    return {true, true};
+
+  if (S != "none")
+    error("unknown -pack-dyn-relocs format: " + S);
+  return {false, false};
+}
+
+static void readCallGraph(MemoryBufferRef MB) {
+  // Build a map from symbol name to section
+  DenseMap<StringRef, const Symbol *> SymbolNameToSymbol;
+  for (InputFile *File : ObjectFiles)
+    for (Symbol *Sym : File->getSymbols())
+      SymbolNameToSymbol[Sym->getName()] = Sym;
+
+  for (StringRef L : args::getLines(MB)) {
+    SmallVector<StringRef, 3> Fields;
+    L.split(Fields, ' ');
+    uint64_t Count;
+    if (Fields.size() != 3 || !to_integer(Fields[2], Count))
+      fatal(MB.getBufferIdentifier() + ": parse error");
+    const Symbol *FromSym = SymbolNameToSymbol.lookup(Fields[0]);
+    const Symbol *ToSym = SymbolNameToSymbol.lookup(Fields[1]);
+    if (Config->WarnSymbolOrdering) {
+      if (!FromSym)
+        warn(MB.getBufferIdentifier() + ": no such symbol: " + Fields[0]);
+      if (!ToSym)
+        warn(MB.getBufferIdentifier() + ": no such symbol: " + Fields[1]);
+    }
+    if (!FromSym || !ToSym || Count == 0)
+      continue;
+    warnUnorderableSymbol(FromSym);
+    warnUnorderableSymbol(ToSym);
+    const Defined *FromSymD = dyn_cast<Defined>(FromSym);
+    const Defined *ToSymD = dyn_cast<Defined>(ToSym);
+    if (!FromSymD || !ToSymD)
+      continue;
+    const auto *FromSB = dyn_cast_or_null<InputSectionBase>(FromSymD->Section);
+    const auto *ToSB = dyn_cast_or_null<InputSectionBase>(ToSymD->Section);
+    if (!FromSB || !ToSB)
+      continue;
+    Config->CallGraphProfile[std::make_pair(FromSB, ToSB)] += Count;
+  }
+}
+
 static bool getCompressDebugSections(opt::InputArgList &Args) {
   StringRef S = Args.getLastArgValue(OPT_compress_debug_sections, "none");
   if (S == "none")
@@ -581,54 +692,101 @@ static bool getCompressDebugSections(opt::InputArgList &Args) {
   return true;
 }
 
-static int parseInt(StringRef S, opt::Arg *Arg) {
-  int V = 0;
-  if (!to_integer(S, V, 10))
-    error(Arg->getSpelling() + ": number expected, but got '" + S + "'");
-  return V;
+static std::pair<StringRef, StringRef> getOldNewOptions(opt::InputArgList &Args,
+                                                        unsigned Id) {
+  auto *Arg = Args.getLastArg(Id);
+  if (!Arg)
+    return {"", ""};
+
+  StringRef S = Arg->getValue();
+  std::pair<StringRef, StringRef> Ret = S.split(';');
+  if (Ret.second.empty())
+    error(Arg->getSpelling() + " expects 'old;new' format, but got " + S);
+  return Ret;
+}
+
+// Parse the symbol ordering file and warn for any duplicate entries.
+static std::vector<StringRef> getSymbolOrderingFile(MemoryBufferRef MB) {
+  SetVector<StringRef> Names;
+  for (StringRef S : args::getLines(MB))
+    if (!Names.insert(S) && Config->WarnSymbolOrdering)
+      warn(MB.getBufferIdentifier() + ": duplicate ordered symbol: " + S);
+
+  return Names.takeVector();
+}
+
+static void parseClangOption(StringRef Opt, const Twine &Msg) {
+  std::string Err;
+  raw_string_ostream OS(Err);
+
+  const char *Argv[] = {Config->ProgName.data(), Opt.data()};
+  if (cl::ParseCommandLineOptions(2, Argv, "", &OS))
+    return;
+  OS.flush();
+  error(Msg + ": " + StringRef(Err).trim());
 }
 
 // Initializes Config members by the command line options.
 void LinkerDriver::readConfigs(opt::InputArgList &Args) {
+  errorHandler().Verbose = Args.hasArg(OPT_verbose);
+  errorHandler().FatalWarnings =
+      Args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false);
+  ThreadsEnabled = Args.hasFlag(OPT_threads, OPT_no_threads, true);
+
   Config->AllowMultipleDefinition =
-      Args.hasArg(OPT_allow_multiple_definition) || hasZOption(Args, "muldefs");
+      Args.hasFlag(OPT_allow_multiple_definition,
+                   OPT_no_allow_multiple_definition, false) ||
+      hasZOption(Args, "muldefs");
   Config->AuxiliaryList = args::getStrings(Args, OPT_auxiliary);
   Config->Bsymbolic = Args.hasArg(OPT_Bsymbolic);
   Config->BsymbolicFunctions = Args.hasArg(OPT_Bsymbolic_functions);
+  Config->CheckSections =
+      Args.hasFlag(OPT_check_sections, OPT_no_check_sections, true);
   Config->Chroot = Args.getLastArgValue(OPT_chroot);
   Config->CompressDebugSections = getCompressDebugSections(Args);
+  Config->Cref = Args.hasFlag(OPT_cref, OPT_no_cref, false);
   Config->DefineCommon = Args.hasFlag(OPT_define_common, OPT_no_define_common,
                                       !Args.hasArg(OPT_relocatable));
   Config->Demangle = Args.hasFlag(OPT_demangle, OPT_no_demangle, true);
   Config->DisableVerify = Args.hasArg(OPT_disable_verify);
   Config->Discard = getDiscard(Args);
+  Config->DwoDir = Args.getLastArgValue(OPT_plugin_opt_dwo_dir_eq);
   Config->DynamicLinker = getDynamicLinker(Args);
   Config->EhFrameHdr =
       Args.hasFlag(OPT_eh_frame_hdr, OPT_no_eh_frame_hdr, false);
   Config->EmitRelocs = Args.hasArg(OPT_emit_relocs);
-  Config->EnableNewDtags = !Args.hasArg(OPT_disable_new_dtags);
+  Config->EnableNewDtags =
+      Args.hasFlag(OPT_enable_new_dtags, OPT_disable_new_dtags, true);
   Config->Entry = Args.getLastArgValue(OPT_entry);
+  Config->ExecuteOnly =
+      Args.hasFlag(OPT_execute_only, OPT_no_execute_only, false);
   Config->ExportDynamic =
       Args.hasFlag(OPT_export_dynamic, OPT_no_export_dynamic, false);
-  errorHandler().FatalWarnings =
-      Args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false);
   Config->FilterList = args::getStrings(Args, OPT_filter);
   Config->Fini = Args.getLastArgValue(OPT_fini, "_fini");
   Config->FixCortexA53Errata843419 = Args.hasArg(OPT_fix_cortex_a53_843419);
   Config->GcSections = Args.hasFlag(OPT_gc_sections, OPT_no_gc_sections, false);
+  Config->GnuUnique = Args.hasFlag(OPT_gnu_unique, OPT_no_gnu_unique, true);
   Config->GdbIndex = Args.hasFlag(OPT_gdb_index, OPT_no_gdb_index, false);
-  Config->ICF = Args.hasFlag(OPT_icf_all, OPT_icf_none, false);
-  Config->ICFData = Args.hasArg(OPT_icf_data);
+  Config->ICF = getICF(Args);
+  Config->IgnoreDataAddressEquality =
+      Args.hasArg(OPT_ignore_data_address_equality);
+  Config->IgnoreFunctionAddressEquality =
+      Args.hasFlag(OPT_ignore_function_address_equality,
+      OPT_no_ignore_function_address_equality, true);
   Config->Init = Args.getLastArgValue(OPT_init, "_init");
   Config->LTOAAPipeline = Args.getLastArgValue(OPT_lto_aa_pipeline);
+  Config->LTODebugPassManager = Args.hasArg(OPT_lto_debug_pass_manager);
+  Config->LTONewPassManager = Args.hasArg(OPT_lto_new_pass_manager);
   Config->LTONewPmPasses = Args.getLastArgValue(OPT_lto_newpm_passes);
   Config->LTOO = args::getInteger(Args, OPT_lto_O, 2);
+  Config->LTOObjPath = Args.getLastArgValue(OPT_plugin_opt_obj_path_eq);
   Config->LTOPartitions = args::getInteger(Args, OPT_lto_partitions, 1);
+  Config->LTOSampleProfile = Args.getLastArgValue(OPT_lto_sample_profile);
   Config->MapFile = Args.getLastArgValue(OPT_Map);
-  Config->NoGnuUnique = Args.hasArg(OPT_no_gnu_unique);
+  Config->MipsGotSize = args::getInteger(Args, OPT_mips_got_size, 0xfff0);
   Config->MergeArmExidx =
       Args.hasFlag(OPT_merge_exidx_entries, OPT_no_merge_exidx_entries, true);
-  Config->NoUndefinedVersion = Args.hasArg(OPT_no_undefined_version);
   Config->NoinhibitExec = Args.hasArg(OPT_noinhibit_exec);
   Config->Nostdlib = Args.hasArg(OPT_nostdlib);
   Config->OFormatBinary = isOutputFormatBinary(Args);
@@ -639,11 +797,13 @@ void LinkerDriver::readConfigs(opt::InputArgList &Args) {
   Config->OrphanHandling = getOrphanHandling(Args);
   Config->OutputFile = Args.getLastArgValue(OPT_o);
 #ifdef __OpenBSD__
-  Config->Pie = Args.hasFlag(OPT_pie, OPT_nopie,
+  Config->Pie = Args.hasFlag(OPT_pie, OPT_no_pie,
       !Args.hasArg(OPT_shared) && !Args.hasArg(OPT_relocatable));
 #else
-  Config->Pie = Args.hasFlag(OPT_pie, OPT_nopie, false);
+  Config->Pie = Args.hasFlag(OPT_pie, OPT_no_pie, false);
 #endif
+  Config->PrintIcfSections =
+      Args.hasFlag(OPT_print_icf_sections, OPT_no_print_icf_sections, false);
   Config->PrintGcSections =
       Args.hasFlag(OPT_print_gc_sections, OPT_no_print_gc_sections, false);
   Config->Rpath = getRpath(Args);
@@ -663,48 +823,59 @@ void LinkerDriver::readConfigs(opt::InputArgList &Args) {
   Config->ThinLTOCachePolicy = CHECK(
       parseCachePruningPolicy(Args.getLastArgValue(OPT_thinlto_cache_policy)),
       "--thinlto-cache-policy: invalid cache policy");
+  Config->ThinLTOEmitImportsFiles =
+      Args.hasArg(OPT_plugin_opt_thinlto_emit_imports_files);
+  Config->ThinLTOIndexOnly = Args.hasArg(OPT_plugin_opt_thinlto_index_only) ||
+                             Args.hasArg(OPT_plugin_opt_thinlto_index_only_eq);
+  Config->ThinLTOIndexOnlyArg =
+      Args.getLastArgValue(OPT_plugin_opt_thinlto_index_only_eq);
   Config->ThinLTOJobs = args::getInteger(Args, OPT_thinlto_jobs, -1u);
-  ThreadsEnabled = Args.hasFlag(OPT_threads, OPT_no_threads, true);
+  Config->ThinLTOObjectSuffixReplace =
+      getOldNewOptions(Args, OPT_plugin_opt_thinlto_object_suffix_replace_eq);
+  Config->ThinLTOPrefixReplace =
+      getOldNewOptions(Args, OPT_plugin_opt_thinlto_prefix_replace_eq);
   Config->Trace = Args.hasArg(OPT_trace);
   Config->Undefined = args::getStrings(Args, OPT_undefined);
+  Config->UndefinedVersion =
+      Args.hasFlag(OPT_undefined_version, OPT_no_undefined_version, true);
+  Config->UseAndroidRelrTags = Args.hasFlag(
+      OPT_use_android_relr_tags, OPT_no_use_android_relr_tags, false);
   Config->UnresolvedSymbols = getUnresolvedSymbolPolicy(Args);
-  Config->Verbose = Args.hasArg(OPT_verbose);
-  errorHandler().Verbose = Config->Verbose;
-  Config->WarnCommon = Args.hasArg(OPT_warn_common);
-  Config->ZCombreloc = !hasZOption(Args, "nocombreloc");
-  Config->ZExecstack = hasZOption(Args, "execstack");
+  Config->WarnBackrefs =
+      Args.hasFlag(OPT_warn_backrefs, OPT_no_warn_backrefs, false);
+  Config->WarnCommon = Args.hasFlag(OPT_warn_common, OPT_no_warn_common, false);
+  Config->WarnSymbolOrdering =
+      Args.hasFlag(OPT_warn_symbol_ordering, OPT_no_warn_symbol_ordering, true);
+  Config->ZCombreloc = getZFlag(Args, "combreloc", "nocombreloc", true);
+  Config->ZCopyreloc = getZFlag(Args, "copyreloc", "nocopyreloc", true);
+  Config->ZExecstack = getZFlag(Args, "execstack", "noexecstack", false);
+  Config->ZHazardplt = hasZOption(Args, "hazardplt");
   Config->ZInitfirst = hasZOption(Args, "initfirst");
-  Config->ZNocopyreloc = hasZOption(Args, "nocopyreloc");
+  Config->ZInterpose = hasZOption(Args, "interpose");
+  Config->ZKeepTextSectionPrefix = getZFlag(
+      Args, "keep-text-section-prefix", "nokeep-text-section-prefix", false);
   Config->ZNodelete = hasZOption(Args, "nodelete");
   Config->ZNodlopen = hasZOption(Args, "nodlopen");
-  Config->ZNow = hasZOption(Args, "now");
+  Config->ZNow = getZFlag(Args, "now", "lazy", false);
   Config->ZOrigin = hasZOption(Args, "origin");
-  Config->ZRelro = !hasZOption(Args, "norelro");
+  Config->ZRelro = getZFlag(Args, "relro", "norelro", true);
   Config->ZRetpolineplt = hasZOption(Args, "retpolineplt");
   Config->ZRodynamic = hasZOption(Args, "rodynamic");
   Config->ZStackSize = args::getZOptionValue(Args, OPT_z, "stack-size", 0);
-  Config->ZText = !hasZOption(Args, "notext");
+  Config->ZText = getZFlag(Args, "text", "notext", true);
   Config->ZWxneeded = hasZOption(Args, "wxneeded");
 
-  // Parse LTO plugin-related options for compatibility with gold.
-  for (auto *Arg : Args.filtered(OPT_plugin_opt, OPT_plugin_opt_eq)) {
-    StringRef S = Arg->getValue();
-    if (S == "disable-verify")
-      Config->DisableVerify = true;
-    else if (S == "save-temps")
-      Config->SaveTemps = true;
-    else if (S.startswith("O"))
-      Config->LTOO = parseInt(S.substr(1), Arg);
-    else if (S.startswith("lto-partitions="))
-      Config->LTOPartitions = parseInt(S.substr(15), Arg);
-    else if (S.startswith("jobs="))
-      Config->ThinLTOJobs = parseInt(S.substr(5), Arg);
-    else if (!S.startswith("/") && !S.startswith("-fresolution=") &&
-             !S.startswith("-pass-through=") && !S.startswith("mcpu=") &&
-             !S.startswith("thinlto") && S != "-function-sections" &&
-             S != "-data-sections")
-      error(Arg->getSpelling() + ": unknown option: " + S);
-  }
+  // Parse LTO options.
+  if (auto *Arg = Args.getLastArg(OPT_plugin_opt_mcpu_eq))
+    parseClangOption(Saver.save("-mcpu=" + StringRef(Arg->getValue())),
+                     Arg->getSpelling());
+
+  for (auto *Arg : Args.filtered(OPT_plugin_opt))
+    parseClangOption(Arg->getValue(), Arg->getSpelling());
+
+  // Parse -mllvm options.
+  for (auto *Arg : Args.filtered(OPT_mllvm))
+    parseClangOption(Arg->getValue(), Arg->getSpelling());
 
   if (Config->LTOO > 3)
     error("invalid optimization level for LTO: " + Twine(Config->LTOO));
@@ -747,17 +918,12 @@ void LinkerDriver::readConfigs(opt::InputArgList &Args) {
 
   std::tie(Config->BuildId, Config->BuildIdVector) = getBuildId(Args);
 
-  if (auto *Arg = Args.getLastArg(OPT_pack_dyn_relocs_eq)) {
-    StringRef S = Arg->getValue();
-    if (S == "android")
-      Config->AndroidPackDynRelocs = true;
-    else if (S != "none")
-      error("unknown -pack-dyn-relocs format: " + S);
-  }
+  std::tie(Config->AndroidPackDynRelocs, Config->RelrPackDynRelocs) =
+      getPackDynRelocs(Args);
 
   if (auto *Arg = Args.getLastArg(OPT_symbol_ordering_file))
     if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
-      Config->SymbolOrderingFile = args::getLines(*Buffer);
+      Config->SymbolOrderingFile = getSymbolOrderingFile(*Buffer);
 
   // If --retain-symbol-file is used, we'll keep only the symbols listed in
   // the file and discard all others.
@@ -785,32 +951,67 @@ void LinkerDriver::readConfigs(opt::InputArgList &Args) {
           {Arg->getValue(), /*IsExternCpp*/ false, /*HasWildcard*/ false});
   }
 
+  // If --export-dynamic-symbol=foo is given and symbol foo is defined in
+  // an object file in an archive file, that object file should be pulled
+  // out and linked. (It doesn't have to behave like that from technical
+  // point of view, but this is needed for compatibility with GNU.)
+  for (auto *Arg : Args.filtered(OPT_export_dynamic_symbol))
+    Config->Undefined.push_back(Arg->getValue());
+
   for (auto *Arg : Args.filtered(OPT_version_script))
-    if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
-      readVersionScript(*Buffer);
+    if (Optional<std::string> Path = searchScript(Arg->getValue())) {
+      if (Optional<MemoryBufferRef> Buffer = readFile(*Path))
+        readVersionScript(*Buffer);
+    } else {
+      error(Twine("cannot find version script ") + Arg->getValue());
+    }
 }
 
 // Some Config members do not directly correspond to any particular
 // command line options, but computed based on other Config values.
 // This function initialize such members. See Config.h for the details
 // of these values.
-static void setConfigs() {
+static void setConfigs(opt::InputArgList &Args) {
   ELFKind Kind = Config->EKind;
   uint16_t Machine = Config->EMachine;
 
-  // There is an ILP32 ABI for x86-64, although it's not very popular.
-  // It is called the x32 ABI.
-  bool IsX32 = (Kind == ELF32LEKind && Machine == EM_X86_64);
-
   Config->CopyRelocs = (Config->Relocatable || Config->EmitRelocs);
   Config->Is64 = (Kind == ELF64LEKind || Kind == ELF64BEKind);
   Config->IsLE = (Kind == ELF32LEKind || Kind == ELF64LEKind);
   Config->Endianness =
       Config->IsLE ? support::endianness::little : support::endianness::big;
   Config->IsMips64EL = (Kind == ELF64LEKind && Machine == EM_MIPS);
-  Config->IsRela = Config->Is64 || IsX32 || Config->MipsN32Abi;
   Config->Pic = Config->Pie || Config->Shared;
   Config->Wordsize = Config->Is64 ? 8 : 4;
+
+  // There is an ILP32 ABI for x86-64, although it's not very popular.
+  // It is called the x32 ABI.
+  bool IsX32 = (Kind == ELF32LEKind && Machine == EM_X86_64);
+
+  // ELF defines two different ways to store relocation addends as shown below:
+  //
+  //  Rel:  Addends are stored to the location where relocations are applied.
+  //  Rela: Addends are stored as part of relocation entry.
+  //
+  // In other words, Rela makes it easy to read addends at the price of extra
+  // 4 or 8 byte for each relocation entry. We don't know why ELF defined two
+  // different mechanisms in the first place, but this is how the spec is
+  // defined.
+  //
+  // You cannot choose which one, Rel or Rela, you want to use. Instead each
+  // ABI defines which one you need to use. The following expression expresses
+  // that.
+  Config->IsRela =
+      (Config->Is64 || IsX32 || Machine == EM_PPC) && Machine != EM_MIPS;
+
+  // If the output uses REL relocations we must store the dynamic relocation
+  // addends to the output sections. We also store addends for RELA relocations
+  // if --apply-dynamic-relocs is used.
+  // We default to not writing the addends when using RELA relocations since
+  // any standard conforming tool can find it in r_addend.
+  Config->WriteAddends = Args.hasFlag(OPT_apply_dynamic_relocs,
+                                      OPT_no_apply_dynamic_relocs, false) ||
+                         !Config->IsRela;
 }
 
 // Returns a value of "-format" option.
@@ -825,6 +1026,10 @@ static bool getBinaryOption(StringRef S) {
 }
 
 void LinkerDriver::createFiles(opt::InputArgList &Args) {
+  // For --{push,pop}-state.
+  std::vector<std::tuple<bool, bool, bool>> Stack;
+
+  // Iterate over argv to process input files and positional arguments.
   for (auto *Arg : Args) {
     switch (Arg->getOption().getUnaliasedOption().getID()) {
     case OPT_library:
@@ -833,8 +1038,15 @@ void LinkerDriver::createFiles(opt::InputArgList &Args) {
     case OPT_INPUT:
       addFile(Arg->getValue(), /*WithLOption=*/false);
       break;
+    case OPT_defsym: {
+      StringRef From;
+      StringRef To;
+      std::tie(From, To) = StringRef(Arg->getValue()).split('=');
+      readDefsym(From, MemoryBufferRef(To, "-defsym"));
+      break;
+    }
     case OPT_script:
-      if (Optional<std::string> Path = searchLinkerScript(Arg->getValue())) {
+      if (Optional<std::string> Path = searchScript(Arg->getValue())) {
         if (Optional<MemoryBufferRef> MB = readFile(*Path))
           readLinkerScript(*MB);
         break;
@@ -862,11 +1074,48 @@ void LinkerDriver::createFiles(opt::InputArgList &Args) {
     case OPT_no_whole_archive:
       InWholeArchive = false;
       break;
+    case OPT_just_symbols:
+      if (Optional<MemoryBufferRef> MB = readFile(Arg->getValue())) {
+        Files.push_back(createObjectFile(*MB));
+        Files.back()->JustSymbols = true;
+      }
+      break;
+    case OPT_start_group:
+      if (InputFile::IsInGroup)
+        error("nested --start-group");
+      InputFile::IsInGroup = true;
+      break;
+    case OPT_end_group:
+      if (!InputFile::IsInGroup)
+        error("stray --end-group");
+      InputFile::IsInGroup = false;
+      ++InputFile::NextGroupId;
+      break;
     case OPT_start_lib:
+      if (InLib)
+        error("nested --start-lib");
+      if (InputFile::IsInGroup)
+        error("may not nest --start-lib in --start-group");
       InLib = true;
+      InputFile::IsInGroup = true;
       break;
     case OPT_end_lib:
+      if (!InLib)
+        error("stray --end-lib");
       InLib = false;
+      InputFile::IsInGroup = false;
+      ++InputFile::NextGroupId;
+      break;
+    case OPT_push_state:
+      Stack.emplace_back(Config->AsNeeded, Config->Static, InWholeArchive);
+      break;
+    case OPT_pop_state:
+      if (Stack.empty()) {
+        error("unbalanced --push-state/--pop-state");
+        break;
+      }
+      std::tie(Config->AsNeeded, Config->Static, InWholeArchive) = Stack.back();
+      Stack.pop_back();
       break;
     }
   }
@@ -939,14 +1188,6 @@ static DenseSet<StringRef> getExcludeLibs(opt::InputArgList &Args) {
   return Ret;
 }
 
-static Optional<StringRef> getArchiveName(InputFile *File) {
-  if (isa<ArchiveFile>(File))
-    return File->getName();
-  if (!File->ArchiveName.empty())
-    return File->ArchiveName;
-  return None;
-}
-
 // Handles the -exclude-libs option. If a static library file is specified
 // by the -exclude-libs option, all public symbols from the archive become
 // private unless otherwise specified by version scripts or something.
@@ -954,18 +1195,140 @@ static Optional<StringRef> getArchiveName(InputFile *File) {
 //
 // This is not a popular option, but some programs such as bionic libc use it.
 template <class ELFT>
-static void excludeLibs(opt::InputArgList &Args, ArrayRef<InputFile *> Files) {
+static void excludeLibs(opt::InputArgList &Args) {
   DenseSet<StringRef> Libs = getExcludeLibs(Args);
   bool All = Libs.count("ALL");
 
-  for (InputFile *File : Files)
-    if (Optional<StringRef> Archive = getArchiveName(File))
-      if (All || Libs.count(path::filename(*Archive)))
+  auto Visit = [&](InputFile *File) {
+    if (!File->ArchiveName.empty())
+      if (All || Libs.count(path::filename(File->ArchiveName)))
         for (Symbol *Sym : File->getSymbols())
           if (!Sym->isLocal() && Sym->File == File)
             Sym->VersionId = VER_NDX_LOCAL;
+  };
+
+  for (InputFile *File : ObjectFiles)
+    Visit(File);
+
+  for (BitcodeFile *File : BitcodeFiles)
+    Visit(File);
+}
+
+// Force Sym to be entered in the output. Used for -u or equivalent.
+template <class ELFT> static void handleUndefined(StringRef Name) {
+  Symbol *Sym = Symtab->find(Name);
+  if (!Sym)
+    return;
+
+  // Since symbol S may not be used inside the program, LTO may
+  // eliminate it. Mark the symbol as "used" to prevent it.
+  Sym->IsUsedInRegularObj = true;
+
+  if (Sym->isLazy())
+    Symtab->fetchLazy<ELFT>(Sym);
+}
+
+template <class ELFT> static bool shouldDemote(Symbol &Sym) {
+  // If all references to a DSO happen to be weak, the DSO is not added to
+  // DT_NEEDED. If that happens, we need to eliminate shared symbols created
+  // from the DSO. Otherwise, they become dangling references that point to a
+  // non-existent DSO.
+  if (auto *S = dyn_cast<SharedSymbol>(&Sym))
+    return !S->getFile<ELFT>().IsNeeded;
+
+  // We are done processing archives, so lazy symbols that were used but not
+  // found can be converted to undefined. We could also just delete the other
+  // lazy symbols, but that seems to be more work than it is worth.
+  return Sym.isLazy() && Sym.IsUsedInRegularObj;
 }
 
+// Some files, such as .so or files between -{start,end}-lib may be removed
+// after their symbols are added to the symbol table. If that happens, we
+// need to remove symbols that refer files that no longer exist, so that
+// they won't appear in the symbol table of the output file.
+//
+// We remove symbols by demoting them to undefined symbol.
+template <class ELFT> static void demoteSymbols() {
+  for (Symbol *Sym : Symtab->getSymbols()) {
+    if (shouldDemote<ELFT>(*Sym)) {
+      bool Used = Sym->Used;
+      replaceSymbol<Undefined>(Sym, nullptr, Sym->getName(), Sym->Binding,
+                               Sym->StOther, Sym->Type);
+      Sym->Used = Used;
+    }
+  }
+}
+
+// The section referred to by S is considered address-significant. Set the
+// KeepUnique flag on the section if appropriate.
+static void markAddrsig(Symbol *S) {
+  if (auto *D = dyn_cast_or_null<Defined>(S))
+    if (D->Section)
+      // We don't need to keep text sections unique under --icf=all even if they
+      // are address-significant.
+      if (Config->ICF == ICFLevel::Safe || !(D->Section->Flags & SHF_EXECINSTR))
+        D->Section->KeepUnique = true;
+}
+
+// Record sections that define symbols mentioned in --keep-unique <symbol>
+// and symbols referred to by address-significance tables. These sections are
+// ineligible for ICF.
+template <class ELFT>
+static void findKeepUniqueSections(opt::InputArgList &Args) {
+  for (auto *Arg : Args.filtered(OPT_keep_unique)) {
+    StringRef Name = Arg->getValue();
+    auto *D = dyn_cast_or_null<Defined>(Symtab->find(Name));
+    if (!D || !D->Section) {
+      warn("could not find symbol " + Name + " to keep unique");
+      continue;
+    }
+    D->Section->KeepUnique = true;
+  }
+
+  // --icf=all --ignore-data-address-equality means that we can ignore
+  // the dynsym and address-significance tables entirely.
+  if (Config->ICF == ICFLevel::All && Config->IgnoreDataAddressEquality)
+    return;
+
+  // Symbols in the dynsym could be address-significant in other executables
+  // or DSOs, so we conservatively mark them as address-significant.
+  for (Symbol *S : Symtab->getSymbols())
+    if (S->includeInDynsym())
+      markAddrsig(S);
+
+  // Visit the address-significance table in each object file and mark each
+  // referenced symbol as address-significant.
+  for (InputFile *F : ObjectFiles) {
+    auto *Obj = cast<ObjFile<ELFT>>(F);
+    ArrayRef<Symbol *> Syms = Obj->getSymbols();
+    if (Obj->AddrsigSec) {
+      ArrayRef<uint8_t> Contents =
+          check(Obj->getObj().getSectionContents(Obj->AddrsigSec));
+      const uint8_t *Cur = Contents.begin();
+      while (Cur != Contents.end()) {
+        unsigned Size;
+        const char *Err;
+        uint64_t SymIndex = decodeULEB128(Cur, &Size, Contents.end(), &Err);
+        if (Err)
+          fatal(toString(F) + ": could not decode addrsig section: " + Err);
+        markAddrsig(Syms[SymIndex]);
+        Cur += Size;
+      }
+    } else {
+      // If an object file does not have an address-significance table,
+      // conservatively mark all of its symbols as address-significant.
+      for (Symbol *S : Syms)
+        markAddrsig(S);
+    }
+  }
+}
+
+static const char *LibcallRoutineNames[] = {
+#define HANDLE_LIBCALL(code, name) name,
+#include "llvm/IR/RuntimeLibcalls.def"
+#undef HANDLE_LIBCALL
+};
+
 // Do actual linking. Note that when this function is called,
 // all linker scripts have already been parsed.
 template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
@@ -1014,14 +1377,6 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
   for (InputFile *F : Files)
     Symtab->addFile<ELFT>(F);
 
-  // Process -defsym option.
-  for (auto *Arg : Args.filtered(OPT_defsym)) {
-    StringRef From;
-    StringRef To;
-    std::tie(From, To) = StringRef(Arg->getValue()).split('=');
-    readDefsym(From, MemoryBufferRef(To, "-defsym"));
-  }
-
   // Now that we have every file, we can decide if we will need a
   // dynamic symbol table.
   // We need one if we were asked to export dynamic symbols or if we are
@@ -1038,24 +1393,39 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
 
   // Handle the `--undefined <sym>` options.
   for (StringRef S : Config->Undefined)
-    Symtab->fetchIfLazy<ELFT>(S);
+    handleUndefined<ELFT>(S);
 
-  // If an entry symbol is in a static archive, pull out that file now
-  // to complete the symbol table. After this, no new names except a
-  // few linker-synthesized ones will be added to the symbol table.
-  Symtab->fetchIfLazy<ELFT>(Config->Entry);
+  // If an entry symbol is in a static archive, pull out that file now.
+  handleUndefined<ELFT>(Config->Entry);
+
+  // If any of our inputs are bitcode files, the LTO code generator may create
+  // references to certain library functions that might not be explicit in the
+  // bitcode file's symbol table. If any of those library functions are defined
+  // in a bitcode file in an archive member, we need to arrange to use LTO to
+  // compile those archive members by adding them to the link beforehand.
+  //
+  // With this the symbol table should be complete. After this, no new names
+  // except a few linker-synthesized ones will be added to the symbol table.
+  if (!BitcodeFiles.empty())
+    for (const char *S : LibcallRoutineNames)
+      handleUndefined<ELFT>(S);
 
   // Return if there were name resolution errors.
   if (errorCount())
     return;
 
-  // Handle undefined symbols in DSOs.
-  if (!Config->Shared)
-    Symtab->scanShlibUndefined<ELFT>();
+  // Now when we read all script files, we want to finalize order of linker
+  // script commands, which can be not yet final because of INSERT commands.
+  Script->processInsertCommands();
+
+  // We want to declare linker script's symbols early,
+  // so that we can version them.
+  // They also might be exported if referenced by DSOs.
+  Script->declareSymbols();
 
   // Handle the -exclude-libs option.
   if (Args.hasArg(OPT_exclude_libs))
-    excludeLibs<ELFT>(Args, Files);
+    excludeLibs<ELFT>(Args);
 
   // Create ElfHeader early. We need a dummy section in
   // addReservedSymbols to mark the created symbols as not absolute.
@@ -1078,10 +1448,18 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
   for (auto *Arg : Args.filtered(OPT_wrap))
     Symtab->addSymbolWrap<ELFT>(Arg->getValue());
 
+  // Do link-time optimization if given files are LLVM bitcode files.
+  // This compiles bitcode files into real object files.
   Symtab->addCombinedLTOObject<ELFT>();
   if (errorCount())
     return;
 
+  // If -thinlto-index-only is given, we should create only "index
+  // files" and not object files. Index file creation is already done
+  // in addCombinedLTOObject, so we are done if that's the case.
+  if (Config->ThinLTOIndexOnly)
+    return;
+
   // Apply symbol renames for -wrap.
   Symtab->applySymbolWrap();
 
@@ -1128,11 +1506,20 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
 
   // Do size optimizations: garbage collection, merging of SHF_MERGE sections
   // and identical code folding.
-  markLive<ELFT>();
   decompressSections();
+  splitSections<ELFT>();
+  markLive<ELFT>();
+  demoteSymbols<ELFT>();
   mergeSections();
-  if (Config->ICF)
+  if (Config->ICF != ICFLevel::None) {
+    findKeepUniqueSections<ELFT>(Args);
     doIcf<ELFT>();
+  }
+
+  // Read the callgraph now that we know what was gced or icfed
+  if (auto *Arg = Args.getLastArg(OPT_call_graph_ordering_file))
+    if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
+      readCallGraph(*Buffer);
 
   // Write the result to the file.
   writeResult<ELFT>();
diff --git a/gnu/llvm/tools/lld/ELF/DriverUtils.cpp b/gnu/llvm/tools/lld/ELF/DriverUtils.cpp
index ddb1977a992..c9273ff1fca 100644
--- a/gnu/llvm/tools/lld/ELF/DriverUtils.cpp
+++ b/gnu/llvm/tools/lld/ELF/DriverUtils.cpp
@@ -29,6 +29,7 @@
 
 using namespace llvm;
 using namespace llvm::sys;
+using namespace llvm::opt;
 
 using namespace lld;
 using namespace lld::elf;
@@ -58,18 +59,18 @@ static void handleColorDiagnostics(opt::InputArgList &Args) {
                               OPT_no_color_diagnostics);
   if (!Arg)
     return;
-  else if (Arg->getOption().getID() == OPT_color_diagnostics)
+  if (Arg->getOption().getID() == OPT_color_diagnostics) {
     errorHandler().ColorDiagnostics = true;
-  else if (Arg->getOption().getID() == OPT_no_color_diagnostics)
+  } else if (Arg->getOption().getID() == OPT_no_color_diagnostics) {
     errorHandler().ColorDiagnostics = false;
-  else {
+  } else {
     StringRef S = Arg->getValue();
     if (S == "always")
       errorHandler().ColorDiagnostics = true;
     else if (S == "never")
       errorHandler().ColorDiagnostics = false;
     else if (S != "auto")
-      error("unknown option: -color-diagnostics=" + S);
+      error("unknown option: --color-diagnostics=" + S);
   }
 }
 
@@ -87,6 +88,29 @@ static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &Args) {
   return cl::TokenizeGNUCommandLine;
 }
 
+// Gold LTO plugin takes a `--plugin-opt foo=bar` option as an alias for
+// `--plugin-opt=foo=bar`. We want to handle `--plugin-opt=foo=` as an
+// option name and `bar` as a value. Unfortunately, OptParser cannot
+// handle an option with a space in it.
+//
+// In this function, we concatenate command line arguments so that
+// `--plugin-opt <foo>` is converted to `--plugin-opt=<foo>`. This is a
+// bit hacky, but looks like it is still better than handling --plugin-opt
+// options by hand.
+static void concatLTOPluginOptions(SmallVectorImpl<const char *> &Args) {
+  SmallVector<const char *, 256> V;
+  for (size_t I = 0, E = Args.size(); I != E; ++I) {
+    StringRef S = Args[I];
+    if ((S == "-plugin-opt" || S == "--plugin-opt") && I + 1 != E) {
+      V.push_back(Saver.save(S + "=" + Args[I + 1]).data());
+      ++I;
+    } else {
+      V.push_back(Args[I]);
+    }
+  }
+  Args = std::move(V);
+}
+
 // Parses a given list of options.
 opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
   // Make InputArgList from string vectors.
@@ -102,6 +126,7 @@ opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
   // Expand response files (arguments in the form of @<filename>)
   // and then parse the argument again.
   cl::ExpandResponseFiles(Saver, getQuotingStyle(Args), Vec);
+  concatLTOPluginOptions(Vec);
   Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
 
   handleColorDiagnostics(Args);
@@ -113,9 +138,9 @@ opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
   return Args;
 }
 
-void elf::printHelp(const char *Argv0) {
-  ELFOptTable().PrintHelp(outs(), Argv0, "lld", false /*ShowHidden*/,
-                          true /*ShowAllAliases*/);
+void elf::printHelp() {
+  ELFOptTable().PrintHelp(outs(), Config->ProgName.data(), "lld",
+                          false /*ShowHidden*/, true /*ShowAllAliases*/);
   outs() << "\n";
 
   // Scripts generated by Libtool versions up to at least 2.4.6 (the most
@@ -123,13 +148,7 @@ void elf::printHelp(const char *Argv0) {
   // in a message for the -help option. If it doesn't match, the scripts
   // assume that the linker doesn't support very basic features such as
   // shared libraries. Therefore, we need to print out at least "elf".
-  // Here, we print out all the targets that we support.
-  outs() << Argv0 << ": supported targets: "
-         << "elf32-i386 elf32-iamcu elf32-littlearm elf32-ntradbigmips "
-         << "elf32-ntradlittlemips elf32-powerpc elf32-tradbigmips "
-         << "elf32-tradlittlemips elf32-x86-64 "
-         << "elf64-amdgpu elf64-littleaarch64 elf64-powerpc elf64-tradbigmips "
-         << "elf64-tradlittlemips elf64-x86-64\n";
+  outs() << Config->ProgName << ": supported targets: elf\n";
 }
 
 // Reconstructs command line arguments so that so that you can re-run
@@ -208,7 +227,7 @@ Optional<std::string> elf::searchLibrary(StringRef Name) {
       int MaxMaj = -1, MaxMin = -1;
       std::error_code EC;
       for (fs::directory_iterator LI(Dir, EC), LE;
-	   !EC && LI != LE; LI = LI.increment(EC)) {
+	   LI != LE; LI = LI.increment(EC)) {
         StringRef FilePath = LI->path();
 	StringRef FileName = path::filename(FilePath);
 	if (!(FileName.startswith(LibName)))
@@ -234,10 +253,10 @@ Optional<std::string> elf::searchLibrary(StringRef Name) {
   return None;
 }
 
-// If a linker script doesn't exist in the current directory, we also look for
-// the script in the '-L' search paths. This matches the behaviour of both '-T'
-// and linker script INPUT() directives in ld.bfd.
-Optional<std::string> elf::searchLinkerScript(StringRef Name) {
+// If a linker/version script doesn't exist in the current directory, we also
+// look for the script in the '-L' search paths. This matches the behaviour of
+// '-T', --version-script=, and linker script INPUT() command in ld.bfd.
+Optional<std::string> elf::searchScript(StringRef Name) {
   if (fs::exists(Name))
     return Name.str();
   return findFromSearchPaths(Name);
diff --git a/gnu/llvm/tools/lld/ELF/LinkerScript.cpp b/gnu/llvm/tools/lld/ELF/LinkerScript.cpp
index 57f4adc5156..42ad9396fab 100644
--- a/gnu/llvm/tools/lld/ELF/LinkerScript.cpp
+++ b/gnu/llvm/tools/lld/ELF/LinkerScript.cpp
@@ -15,13 +15,13 @@
 #include "Config.h"
 #include "InputSection.h"
 #include "OutputSections.h"
-#include "Strings.h"
 #include "SymbolTable.h"
 #include "Symbols.h"
 #include "SyntheticSections.h"
 #include "Target.h"
 #include "Writer.h"
 #include "lld/Common/Memory.h"
+#include "lld/Common/Strings.h"
 #include "lld/Common/Threads.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
@@ -74,7 +74,7 @@ uint64_t ExprValue::getSectionOffset() const {
   // If the alignment is trivial, we don't have to compute the full
   // value to know the offset. This allows this function to succeed in
   // cases where the output section is not yet known.
-  if (Alignment == 1)
+  if (Alignment == 1 && (!Sec || !Sec->getOutputSection()))
     return Val;
   return getValue() - getSecAddr();
 }
@@ -102,28 +102,68 @@ OutputSection *LinkerScript::getOrCreateOutputSection(StringRef Name) {
   return CmdRef;
 }
 
+// Expands the memory region by the specified size.
+static void expandMemoryRegion(MemoryRegion *MemRegion, uint64_t Size,
+                               StringRef RegionName, StringRef SecName) {
+  MemRegion->CurPos += Size;
+  uint64_t NewSize = MemRegion->CurPos - MemRegion->Origin;
+  if (NewSize > MemRegion->Length)
+    error("section '" + SecName + "' will not fit in region '" + RegionName +
+          "': overflowed by " + Twine(NewSize - MemRegion->Length) + " bytes");
+}
+
+void LinkerScript::expandMemoryRegions(uint64_t Size) {
+  if (Ctx->MemRegion)
+    expandMemoryRegion(Ctx->MemRegion, Size, Ctx->MemRegion->Name,
+                       Ctx->OutSec->Name);
+  // Only expand the LMARegion if it is different from MemRegion.
+  if (Ctx->LMARegion && Ctx->MemRegion != Ctx->LMARegion)
+    expandMemoryRegion(Ctx->LMARegion, Size, Ctx->LMARegion->Name,
+                       Ctx->OutSec->Name);
+}
+
+void LinkerScript::expandOutputSection(uint64_t Size) {
+  Ctx->OutSec->Size += Size;
+  expandMemoryRegions(Size);
+}
+
 void LinkerScript::setDot(Expr E, const Twine &Loc, bool InSec) {
   uint64_t Val = E().getValue();
   if (Val < Dot && InSec)
     error(Loc + ": unable to move location counter backward for: " +
           Ctx->OutSec->Name);
-  Dot = Val;
 
   // Update to location counter means update to section size.
   if (InSec)
-    Ctx->OutSec->Size = Dot - Ctx->OutSec->Addr;
+    expandOutputSection(Val - Dot);
+  else
+    expandMemoryRegions(Val - Dot);
+
+  Dot = Val;
 }
 
-// This function is called from processSectionCommands,
-// while we are fixing the output section layout.
-void LinkerScript::addSymbol(SymbolAssignment *Cmd) {
+// Used for handling linker symbol assignments, for both finalizing
+// their values and doing early declarations. Returns true if symbol
+// should be defined from linker script.
+static bool shouldDefineSym(SymbolAssignment *Cmd) {
   if (Cmd->Name == ".")
-    return;
+    return false;
 
-  // If a symbol was in PROVIDE(), we need to define it only when
-  // it is a referenced undefined symbol.
+  if (!Cmd->Provide)
+    return true;
+
+  // If a symbol was in PROVIDE(), we need to define it only
+  // when it is a referenced undefined symbol.
   Symbol *B = Symtab->find(Cmd->Name);
-  if (Cmd->Provide && (!B || B->isDefined()))
+  if (B && !B->isDefined())
+    return true;
+  return false;
+}
+
+// This function is called from processSectionCommands,
+// while we are fixing the output section layout.
+void LinkerScript::addSymbol(SymbolAssignment *Cmd) {
+  if (!shouldDefineSym(Cmd))
     return;
 
   // Define a symbol.
@@ -153,6 +193,76 @@ void LinkerScript::addSymbol(SymbolAssignment *Cmd) {
   Cmd->Sym = cast<Defined>(Sym);
 }
 
+// This function is called from LinkerScript::declareSymbols.
+// It creates a placeholder symbol if needed.
+static void declareSymbol(SymbolAssignment *Cmd) {
+  if (!shouldDefineSym(Cmd))
+    return;
+
+  // We can't calculate final value right now.
+  Symbol *Sym;
+  uint8_t Visibility = Cmd->Hidden ? STV_HIDDEN : STV_DEFAULT;
+  std::tie(Sym, std::ignore) = Symtab->insert(Cmd->Name, /*Type*/ 0, Visibility,
+                                              /*CanOmitFromDynSym*/ false,
+                                              /*File*/ nullptr);
+  replaceSymbol<Defined>(Sym, nullptr, Cmd->Name, STB_GLOBAL, Visibility,
+                         STT_NOTYPE, 0, 0, nullptr);
+  Cmd->Sym = cast<Defined>(Sym);
+  Cmd->Provide = false;
+}
+
+// This method is used to handle INSERT AFTER statement. Here we rebuild
+// the list of script commands to mix sections inserted into.
+void LinkerScript::processInsertCommands() {
+  std::vector<BaseCommand *> V;
+  auto Insert = [&](std::vector<BaseCommand *> &From) {
+    V.insert(V.end(), From.begin(), From.end());
+    From.clear();
+  };
+
+  for (BaseCommand *Base : SectionCommands) {
+    if (auto *OS = dyn_cast<OutputSection>(Base)) {
+      Insert(InsertBeforeCommands[OS->Name]);
+      V.push_back(Base);
+      Insert(InsertAfterCommands[OS->Name]);
+      continue;
+    }
+    V.push_back(Base);
+  }
+
+  for (auto &Cmds : {InsertBeforeCommands, InsertAfterCommands})
+    for (const std::pair<StringRef, std::vector<BaseCommand *>> &P : Cmds)
+      if (!P.second.empty())
+        error("unable to INSERT AFTER/BEFORE " + P.first +
+              ": section not defined");
+
+  SectionCommands = std::move(V);
+}
+
+// Symbols defined in script should not be inlined by LTO. At the same time
+// we don't know their final values until late stages of link. Here we scan
+// over symbol assignment commands and create placeholder symbols if needed.
+void LinkerScript::declareSymbols() {
+  assert(!Ctx);
+  for (BaseCommand *Base : SectionCommands) {
+    if (auto *Cmd = dyn_cast<SymbolAssignment>(Base)) {
+      declareSymbol(Cmd);
+      continue;
+    }
+
+    // If the output section directive has constraints,
+    // we can't say for sure if it is going to be included or not.
+    // Skip such sections for now. Improve the checks if we ever
+    // need symbols from that sections to be declared early.
+    auto *Sec = cast<OutputSection>(Base);
+    if (Sec->Constraint != ConstraintKind::NoConstraint)
+      continue;
+    for (BaseCommand *Base2 : Sec->SectionCommands)
+      if (auto *Cmd = dyn_cast<SymbolAssignment>(Base2))
+        declareSymbol(Cmd);
+  }
+}
+
 // This function is called from assignAddresses, while we are
 // fixing the output section addresses. This function is supposed
 // to set the final value for a given symbol assignment.
@@ -249,23 +359,11 @@ static void sortSections(MutableArrayRef<InputSection *> Vec,
 //    --sort-section is handled as an inner SORT command.
 // 3. If one SORT command is given, and if it is SORT_NONE, don't sort.
 // 4. If no SORT command is given, sort according to --sort-section.
-// 5. If no SORT commands are given and --sort-section is not specified,
-//    apply sorting provided by --symbol-ordering-file if any exist.
-static void sortInputSections(
-    MutableArrayRef<InputSection *> Vec, const SectionPattern &Pat,
-    const DenseMap<SectionBase *, int> &Order) {
+static void sortInputSections(MutableArrayRef<InputSection *> Vec,
+                              const SectionPattern &Pat) {
   if (Pat.SortOuter == SortSectionPolicy::None)
     return;
 
-  if (Pat.SortOuter == SortSectionPolicy::Default &&
-      Config->SortSection == SortSectionPolicy::Default) {
-    // If -symbol-ordering-file was given, sort accordingly.
-    // Usually, Order is empty.
-    if (!Order.empty())
-      sortByOrder(Vec, [&](InputSectionBase *S) { return Order.lookup(S); });
-    return;
-  }
-
   if (Pat.SortInner == SortSectionPolicy::Default)
     sortSections(Vec, Config->SortSection);
   else
@@ -275,8 +373,7 @@ static void sortInputSections(
 
 // Compute and remember which sections the InputSectionDescription matches.
 std::vector<InputSection *>
-LinkerScript::computeInputSections(const InputSectionDescription *Cmd,
-                                   const DenseMap<SectionBase *, int> &Order) {
+LinkerScript::computeInputSections(const InputSectionDescription *Cmd) {
   std::vector<InputSection *> Ret;
 
   // Collects all sections that satisfy constraints of Cmd.
@@ -290,8 +387,11 @@ LinkerScript::computeInputSections(const InputSectionDescription *Cmd,
       // For -emit-relocs we have to ignore entries like
       //   .rela.dyn : { *(.rela.data) }
       // which are common because they are in the default bfd script.
-      if (Sec->Type == SHT_REL || Sec->Type == SHT_RELA)
-        continue;
+      // We do not ignore SHT_REL[A] linker-synthesized sections here because
+      // want to support scripts that do custom layout for them.
+      if (auto *IS = dyn_cast<InputSection>(Sec))
+        if (IS->getRelocatedSection())
+          continue;
 
       std::string Filename = getFilename(Sec->File);
       if (!Cmd->FilePat.match(Filename) ||
@@ -307,7 +407,7 @@ LinkerScript::computeInputSections(const InputSectionDescription *Cmd,
     }
 
     sortInputSections(MutableArrayRef<InputSection *>(Ret).slice(SizeBefore),
-                      Pat, Order);
+                      Pat);
   }
   return Ret;
 }
@@ -315,22 +415,31 @@ LinkerScript::computeInputSections(const InputSectionDescription *Cmd,
 void LinkerScript::discard(ArrayRef<InputSection *> V) {
   for (InputSection *S : V) {
     if (S == InX::ShStrTab || S == InX::Dynamic || S == InX::DynSymTab ||
-        S == InX::DynStrTab)
+        S == InX::DynStrTab || S == InX::RelaPlt || S == InX::RelaDyn ||
+        S == InX::RelrDyn)
       error("discarding " + S->Name + " section is not allowed");
 
+    // You can discard .hash and .gnu.hash sections by linker scripts. Since
+    // they are synthesized sections, we need to handle them differently than
+    // other regular sections.
+    if (S == InX::GnuHashTab)
+      InX::GnuHashTab = nullptr;
+    if (S == InX::HashTab)
+      InX::HashTab = nullptr;
+
     S->Assigned = false;
     S->Live = false;
     discard(S->DependentSections);
   }
 }
 
-std::vector<InputSection *> LinkerScript::createInputSectionList(
-    OutputSection &OutCmd, const DenseMap<SectionBase *, int> &Order) {
+std::vector<InputSection *>
+LinkerScript::createInputSectionList(OutputSection &OutCmd) {
   std::vector<InputSection *> Ret;
 
   for (BaseCommand *Base : OutCmd.SectionCommands) {
     if (auto *Cmd = dyn_cast<InputSectionDescription>(Base)) {
-      Cmd->Sections = computeInputSections(Cmd, Order);
+      Cmd->Sections = computeInputSections(Cmd);
       Ret.insert(Ret.end(), Cmd->Sections.begin(), Cmd->Sections.end());
     }
   }
@@ -359,7 +468,6 @@ void LinkerScript::processSectionCommands() {
   Ctx->OutSec = Aether;
 
   size_t I = 0;
-  DenseMap<SectionBase *, int> Order = buildSectionOrder();
   // Add input sections to output sections.
   for (BaseCommand *Base : SectionCommands) {
     // Handle symbol assignments outside of any output section.
@@ -369,12 +477,13 @@ void LinkerScript::processSectionCommands() {
     }
 
     if (auto *Sec = dyn_cast<OutputSection>(Base)) {
-      std::vector<InputSection *> V = createInputSectionList(*Sec, Order);
+      std::vector<InputSection *> V = createInputSectionList(*Sec);
 
       // The output section name `/DISCARD/' is special.
       // Any input section assigned to it is discarded.
       if (Sec->Name == "/DISCARD/") {
         discard(V);
+        Sec->SectionCommands.clear();
         continue;
       }
 
@@ -414,6 +523,8 @@ void LinkerScript::processSectionCommands() {
       Sec->SectionIndex = I++;
       if (Sec->Noload)
         Sec->Type = SHT_NOBITS;
+      if (Sec->NonAlloc)
+        Sec->Flags &= ~(uint64_t)SHF_ALLOC;
     }
   }
   Ctx = nullptr;
@@ -484,7 +595,7 @@ static OutputSection *addInputSec(StringMap<OutputSection *> &Map,
   // ignored. We should not have two output .text sections just because one was
   // in a group and another was not for example.
   //
-  // It also seems that that wording was a late addition and didn't get the
+  // It also seems that wording was a late addition and didn't get the
   // necessary scrutiny.
   //
   // Merging sections with different flags is expected by some users. One
@@ -529,11 +640,11 @@ static OutputSection *addInputSec(StringMap<OutputSection *> &Map,
 void LinkerScript::addOrphanSections() {
   unsigned End = SectionCommands.size();
   StringMap<OutputSection *> Map;
-
   std::vector<OutputSection *> V;
-  for (InputSectionBase *S : InputSections) {
+
+  auto Add = [&](InputSectionBase *S) {
     if (!S->Live || S->Parent)
-      continue;
+      return;
 
     StringRef Name = getOutputSectionName(S);
 
@@ -545,12 +656,24 @@ void LinkerScript::addOrphanSections() {
     if (OutputSection *Sec =
             findByName(makeArrayRef(SectionCommands).slice(0, End), Name)) {
       Sec->addSection(cast<InputSection>(S));
-      continue;
+      return;
     }
 
     if (OutputSection *OS = addInputSec(Map, S, Name))
       V.push_back(OS);
-    assert(S->getOutputSection()->SectionIndex == INT_MAX);
+    assert(S->getOutputSection()->SectionIndex == UINT32_MAX);
+  };
+
+  // For futher --emit-reloc handling code we need target output section
+  // to be created before we create relocation output section, so we want
+  // to create target sections first. We do not want priority handling
+  // for synthetic sections because them are special.
+  for (InputSectionBase *IS : InputSections) {
+    if (auto *Sec = dyn_cast<InputSection>(IS))
+      if (InputSectionBase *Rel = Sec->getRelocatedSection())
+        if (auto *RelIS = dyn_cast_or_null<InputSectionBase>(Rel->Parent))
+          Add(RelIS);
+    Add(IS);
   }
 
   // If no SECTIONS command was given, we should insert sections commands
@@ -585,33 +708,15 @@ void LinkerScript::output(InputSection *S) {
   // Update output section size after adding each section. This is so that
   // SIZEOF works correctly in the case below:
   // .foo { *(.aaa) a = SIZEOF(.foo); *(.bbb) }
-  Ctx->OutSec->Size = Pos - Ctx->OutSec->Addr;
-
-  // If there is a memory region associated with this input section, then
-  // place the section in that region and update the region index.
-  if (Ctx->LMARegion)
-    Ctx->LMARegion->CurPos += Pos - Before;
-  // FIXME: should we also produce overflow errors for LMARegion?
-
-  if (Ctx->MemRegion) {
-    uint64_t &CurOffset = Ctx->MemRegion->CurPos;
-    CurOffset += Pos - Before;
-    uint64_t CurSize = CurOffset - Ctx->MemRegion->Origin;
-    if (CurSize > Ctx->MemRegion->Length) {
-      uint64_t OverflowAmt = CurSize - Ctx->MemRegion->Length;
-      error("section '" + Ctx->OutSec->Name + "' will not fit in region '" +
-            Ctx->MemRegion->Name + "': overflowed by " + Twine(OverflowAmt) +
-            " bytes");
-    }
-  }
+  expandOutputSection(Pos - Before);
 }
 
 void LinkerScript::switchTo(OutputSection *Sec) {
-  if (Ctx->OutSec == Sec)
-    return;
-
   Ctx->OutSec = Sec;
+
+  uint64_t Before = advance(0, 1);
   Ctx->OutSec->Addr = advance(0, Ctx->OutSec->Alignment);
+  expandMemoryRegions(Ctx->OutSec->Addr - Before);
 }
 
 // This function searches for a memory region to place the given output
@@ -646,6 +751,13 @@ MemoryRegion *LinkerScript::findMemoryRegion(OutputSection *Sec) {
   return nullptr;
 }
 
+static OutputSection *findFirstSection(PhdrEntry *Load) {
+  for (OutputSection *Sec : OutputSections)
+    if (Sec->PtLoad == Load)
+      return Sec;
+  return nullptr;
+}
+
 // This function assigns offsets to input sections and an output section
 // for a single sections command (e.g. ".text { *(.text); }").
 void LinkerScript::assignOffsets(OutputSection *Sec) {
@@ -659,24 +771,26 @@ void LinkerScript::assignOffsets(OutputSection *Sec) {
   if (Ctx->MemRegion)
     Dot = Ctx->MemRegion->CurPos;
 
-  switchTo(Sec);
-
   if (Sec->LMAExpr)
     Ctx->LMAOffset = Sec->LMAExpr().getValue() - Dot;
 
   if (MemoryRegion *MR = Sec->LMARegion)
     Ctx->LMAOffset = MR->CurPos - Dot;
 
+  switchTo(Sec);
+
   // If neither AT nor AT> is specified for an allocatable section, the linker
   // will set the LMA such that the difference between VMA and LMA for the
   // section is the same as the preceding output section in the same region
   // https://sourceware.org/binutils/docs-2.20/ld/Output-Section-LMA.html
+  // This, however, should only be done by the first "non-header" section
+  // in the segment.
   if (PhdrEntry *L = Ctx->OutSec->PtLoad)
-    L->LMAOffset = Ctx->LMAOffset;
+    if (Sec == findFirstSection(L))
+      L->LMAOffset = Ctx->LMAOffset;
 
-  // The Size previously denoted how many InputSections had been added to this
-  // section, and was used for sorting SHF_LINK_ORDER sections. Reset it to
-  // compute the actual size value.
+  // We can call this method multiple times during the creation of
+  // thunks and want to start over calculation each time.
   Sec->Size = 0;
 
   // We visited SectionsCommands from processSectionCommands to
@@ -685,7 +799,9 @@ void LinkerScript::assignOffsets(OutputSection *Sec) {
   for (BaseCommand *Base : Sec->SectionCommands) {
     // This handles the assignments to symbol or to the dot.
     if (auto *Cmd = dyn_cast<SymbolAssignment>(Base)) {
+      Cmd->Addr = Dot;
       assignSymbol(Cmd, true);
+      Cmd->Size = Dot - Cmd->Addr;
       continue;
     }
 
@@ -693,17 +809,7 @@ void LinkerScript::assignOffsets(OutputSection *Sec) {
     if (auto *Cmd = dyn_cast<ByteCommand>(Base)) {
       Cmd->Offset = Dot - Ctx->OutSec->Addr;
       Dot += Cmd->Size;
-      if (Ctx->MemRegion)
-        Ctx->MemRegion->CurPos += Cmd->Size;
-      if (Ctx->LMARegion)
-        Ctx->LMARegion->CurPos += Cmd->Size;
-      Ctx->OutSec->Size = Dot - Ctx->OutSec->Addr;
-      continue;
-    }
-
-    // Handle ASSERT().
-    if (auto *Cmd = dyn_cast<AssertCommand>(Base)) {
-      Cmd->Expression();
+      expandOutputSection(Cmd->Size);
       continue;
     }
 
@@ -728,24 +834,28 @@ void LinkerScript::assignOffsets(OutputSection *Sec) {
   }
 }
 
-void LinkerScript::removeEmptyCommands() {
-  // It is common practice to use very generic linker scripts. So for any
-  // given run some of the output sections in the script will be empty.
-  // We could create corresponding empty output sections, but that would
-  // clutter the output.
-  // We instead remove trivially empty sections. The bfd linker seems even
-  // more aggressive at removing them.
-  llvm::erase_if(SectionCommands, [&](BaseCommand *Base) {
-    if (auto *Sec = dyn_cast<OutputSection>(Base))
-      return !Sec->Live;
+static bool isDiscardable(OutputSection &Sec) {
+  // We do not remove empty sections that are explicitly
+  // assigned to any segment.
+  if (!Sec.Phdrs.empty())
     return false;
-  });
-}
 
-static bool isAllSectionDescription(const OutputSection &Cmd) {
-  for (BaseCommand *Base : Cmd.SectionCommands)
+  // We do not want to remove sections that reference symbols in address and
+  // other expressions. We add script symbols as undefined, and want to ensure
+  // all of them are defined in the output, hence have to keep them.
+  if (Sec.ExpressionsUseSymbols)
+    return false;
+
+  for (BaseCommand *Base : Sec.SectionCommands) {
+    if (auto Cmd = dyn_cast<SymbolAssignment>(Base))
+      // Don't create empty output sections just for unreferenced PROVIDE
+      // symbols.
+      if (Cmd->Name != "." && !Cmd->Sym)
+        continue;
+
     if (!isa<InputSectionDescription>(*Base))
       return false;
+  }
   return true;
 }
 
@@ -761,7 +871,7 @@ void LinkerScript::adjustSectionsBeforeSorting() {
   // Given that we want to create the section, we have to worry what impact
   // it will have on the link. For example, if we just create a section with
   // 0 for flags, it would change which PT_LOADs are created.
-  // We could remember that that particular section is dummy and ignore it in
+  // We could remember that particular section is dummy and ignore it in
   // other parts of the linker, but unfortunately there are quite a few places
   // that would need to change:
   //   * The program header creation.
@@ -772,7 +882,7 @@ void LinkerScript::adjustSectionsBeforeSorting() {
   // the previous sections. Only a few flags are needed to keep the impact low.
   uint64_t Flags = SHF_ALLOC;
 
-  for (BaseCommand *Cmd : SectionCommands) {
+  for (BaseCommand *&Cmd : SectionCommands) {
     auto *Sec = dyn_cast<OutputSection>(Cmd);
     if (!Sec)
       continue;
@@ -782,25 +892,37 @@ void LinkerScript::adjustSectionsBeforeSorting() {
       Sec->Alignment =
           std::max<uint32_t>(Sec->Alignment, Sec->AlignExpr().getValue());
 
-    if (Sec->Live) {
-      Flags = Sec->Flags & (SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR);
-      continue;
+    // A live output section means that some input section was added to it. It
+    // might have been removed (if it was empty synthetic section), but we at
+    // least know the flags.
+    if (Sec->Live)
+      Flags = Sec->Flags;
+
+    // We do not want to keep any special flags for output section
+    // in case it is empty.
+    bool IsEmpty = getInputSections(Sec).empty();
+    if (IsEmpty)
+      Sec->Flags = Flags & (SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR);
+
+    if (IsEmpty && isDiscardable(*Sec)) {
+      Sec->Live = false;
+      Cmd = nullptr;
     }
-
-    if (isAllSectionDescription(*Sec))
-      continue;
-
-    Sec->Live = true;
-    Sec->Flags = Flags;
   }
+
+  // It is common practice to use very generic linker scripts. So for any
+  // given run some of the output sections in the script will be empty.
+  // We could create corresponding empty output sections, but that would
+  // clutter the output.
+  // We instead remove trivially empty sections. The bfd linker seems even
+  // more aggressive at removing them.
+  llvm::erase_if(SectionCommands, [&](BaseCommand *Base) { return !Base; });
 }
 
 void LinkerScript::adjustSectionsAfterSorting() {
   // Try and find an appropriate memory region to assign offsets in.
   for (BaseCommand *Base : SectionCommands) {
     if (auto *Sec = dyn_cast<OutputSection>(Base)) {
-      if (!Sec->Live)
-        continue;
       if (!Sec->LMARegionName.empty()) {
         if (MemoryRegion *M = MemoryRegions.lookup(Sec->LMARegionName))
           Sec->LMARegion = M;
@@ -818,9 +940,9 @@ void LinkerScript::adjustSectionsAfterSorting() {
   // PHDRS { seg PT_LOAD; }
   // SECTIONS { .aaa : { *(.aaa) } }
   std::vector<StringRef> DefPhdrs;
-  auto FirstPtLoad =
-      std::find_if(PhdrsCommands.begin(), PhdrsCommands.end(),
-                   [](const PhdrsCommand &Cmd) { return Cmd.Type == PT_LOAD; });
+  auto FirstPtLoad = llvm::find_if(PhdrsCommands, [](const PhdrsCommand &Cmd) {
+    return Cmd.Type == PT_LOAD;
+  });
   if (FirstPtLoad != PhdrsCommands.end())
     DefPhdrs.push_back(FirstPtLoad->Name);
 
@@ -842,11 +964,13 @@ void LinkerScript::adjustSectionsAfterSorting() {
   }
 }
 
-static OutputSection *findFirstSection(PhdrEntry *Load) {
-  for (OutputSection *Sec : OutputSections)
-    if (Sec->PtLoad == Load)
-      return Sec;
-  return nullptr;
+static uint64_t computeBase(uint64_t Min, bool AllocateHeaders) {
+  // If there is no SECTIONS or if the linkerscript is explicit about program
+  // headers, do our best to allocate them.
+  if (!Script->HasSectionsCommand || AllocateHeaders)
+    return 0;
+  // Otherwise only allocate program headers if that would not add a page.
+  return alignDown(Min, Config->MaxPageSize);
 }
 
 // Try to find an address for the file and program headers output sections,
@@ -872,17 +996,22 @@ void LinkerScript::allocateHeaders(std::vector<PhdrEntry *> &Phdrs) {
     return;
   PhdrEntry *FirstPTLoad = *It;
 
+  bool HasExplicitHeaders =
+      llvm::any_of(PhdrsCommands, [](const PhdrsCommand &Cmd) {
+        return Cmd.HasPhdrs || Cmd.HasFilehdr;
+      });
   uint64_t HeaderSize = getHeaderSize();
-  // When linker script with SECTIONS is being used, don't output headers
-  // unless there's a space for them.
-  uint64_t Base = HasSectionsCommand ? alignDown(Min, Config->MaxPageSize) : 0;
-  if (HeaderSize <= Min - Base || Script->hasPhdrsCommands()) {
+  if (HeaderSize <= Min - computeBase(Min, HasExplicitHeaders)) {
     Min = alignDown(Min - HeaderSize, Config->MaxPageSize);
     Out::ElfHeader->Addr = Min;
     Out::ProgramHeaders->Addr = Min + Out::ElfHeader->Size;
     return;
   }
 
+  // Error if we were explicitly asked to allocate headers.
+  if (HasExplicitHeaders)
+    error("could not allocate headers");
+
   Out::ElfHeader->PtLoad = nullptr;
   Out::ProgramHeaders->PtLoad = nullptr;
   FirstPTLoad->FirstSec = findFirstSection(FirstPTLoad);
@@ -926,15 +1055,11 @@ void LinkerScript::assignAddresses() {
 
   for (BaseCommand *Base : SectionCommands) {
     if (auto *Cmd = dyn_cast<SymbolAssignment>(Base)) {
+      Cmd->Addr = Dot;
       assignSymbol(Cmd, false);
+      Cmd->Size = Dot - Cmd->Addr;
       continue;
     }
-
-    if (auto *Cmd = dyn_cast<AssertCommand>(Base)) {
-      Cmd->Expression();
-      continue;
-    }
-
     assignOffsets(cast<OutputSection>(Base));
   }
   Ctx = nullptr;
@@ -998,9 +1123,9 @@ ExprValue LinkerScript::getSymbolValue(StringRef Name, const Twine &Loc) {
   if (Symbol *Sym = Symtab->find(Name)) {
     if (auto *DS = dyn_cast<Defined>(Sym))
       return {DS->Section, false, DS->Value, Loc};
-    if (auto *SS = dyn_cast<SharedSymbol>(Sym))
-      if (!ErrorOnMissingSection || SS->CopyRelSec)
-        return {SS->CopyRelSec, false, 0, Loc};
+    if (isa<SharedSymbol>(Sym))
+      if (!ErrorOnMissingSection)
+        return {nullptr, false, 0, Loc};
   }
 
   error(Loc + ": symbol not found: " + Name);
diff --git a/gnu/llvm/tools/lld/ELF/Options.td b/gnu/llvm/tools/lld/ELF/Options.td
index affc0b8a4ae..068ad546db6 100644
--- a/gnu/llvm/tools/lld/ELF/Options.td
+++ b/gnu/llvm/tools/lld/ELF/Options.td
@@ -5,65 +5,90 @@ include "llvm/Option/OptParser.td"
 class F<string name>: Flag<["--", "-"], name>;
 class J<string name>: Joined<["--", "-"], name>;
 
-multiclass Eq<string name> {
-  def "": Separate<["--", "-"], name>;
-  def _eq: Joined<["--", "-"], name # "=">, Alias<!cast<Separate>(NAME)>;
+multiclass Eq<string name, string help> {
+  def NAME: Separate<["--", "-"], name>;
+  def NAME # _eq: Joined<["--", "-"], name # "=">, Alias<!cast<Separate>(NAME)>,
+    HelpText<help>;
 }
 
-defm auxiliary: Eq<"auxiliary">,
-  HelpText<"Set DT_AUXILIARY field to the specified name">;
+multiclass B<string name, string help1, string help2> {
+  def NAME: Flag<["--", "-"], name>, HelpText<help1>;
+  def no_ # NAME: Flag<["--", "-"], "no-" # name>, HelpText<help2>;
+}
+
+defm auxiliary: Eq<"auxiliary", "Set DT_AUXILIARY field to the specified name">;
 
 def Bsymbolic: F<"Bsymbolic">, HelpText<"Bind defined symbols locally">;
 
 def Bsymbolic_functions: F<"Bsymbolic-functions">,
   HelpText<"Bind defined function symbols locally">;
 
-def Bdynamic: F<"Bdynamic">, HelpText<"Link against shared libraries">;
+def Bdynamic: F<"Bdynamic">, HelpText<"Link against shared libraries (default)">;
 
 def Bstatic: F<"Bstatic">, HelpText<"Do not link against shared libraries">;
 
-def build_id: F<"build-id">, HelpText<"Generate build ID note">;
+def build_id: F<"build-id">, HelpText<"Alias for --build-id=fast">;
+
+def build_id_eq: J<"build-id=">, HelpText<"Generate build ID note">,
+  MetaVarName<"[fast,md5,sha,uuid,0x<hexstring>]">;
 
-def build_id_eq: J<"build-id=">, HelpText<"Generate build ID note">;
+defm check_sections: B<"check-sections",
+    "Check section addresses for overlaps (default)",
+    "Do not check section addresses for overlaps">;
 
-defm compress_debug_sections : Eq<"compress-debug-sections">,
-  HelpText<"Compress DWARF debug sections">;
+defm compress_debug_sections:
+  Eq<"compress-debug-sections", "Compress DWARF debug sections">,
+  MetaVarName<"[none,zlib]">;
 
-defm defsym: Eq<"defsym">, HelpText<"Define a symbol alias">;
+defm defsym: Eq<"defsym", "Define a symbol alias">, MetaVarName<"<symbol>=<value>">;
 
-defm library_path: Eq<"library-path">,
-  HelpText<"Add a directory to the library search path">, MetaVarName<"<dir>">;
+defm library_path:
+  Eq<"library-path", "Add a directory to the library search path">, MetaVarName<"<dir>">;
 
 def O: JoinedOrSeparate<["-"], "O">, HelpText<"Optimize output file size">;
 
-defm Tbss: Eq<"Tbss">,
-  HelpText<"Same as --section-start with .bss as the sectionname">;
+defm Tbss: Eq<"Tbss", "Same as --section-start with .bss as the sectionname">;
 
-defm Tdata: Eq<"Tdata">,
-  HelpText<"Same as --section-start with .data as the sectionname">;
+defm Tdata: Eq<"Tdata", "Same as --section-start with .data as the sectionname">;
 
-defm Ttext: Eq<"Ttext">,
-  HelpText<"Same as --section-start with .text as the sectionname">;
+defm Ttext: Eq<"Ttext", "Same as --section-start with .text as the sectionname">;
 
-def allow_multiple_definition: F<"allow-multiple-definition">,
-  HelpText<"Allow multiple definitions">;
+defm allow_multiple_definition: B<"allow-multiple-definition",
+    "Allow multiple definitions",
+    "Do not allow multiple definitions (default)">;
 
-def as_needed: F<"as-needed">,
-  HelpText<"Only set DT_NEEDED for shared libraries if used">;
+defm apply_dynamic_relocs: B<"apply-dynamic-relocs",
+    "Apply link-time values for dynamic relocations",
+    "Do not apply link-time values for dynamic relocations (default)">;
+
+defm as_needed: B<"as-needed",
+    "Only set DT_NEEDED for shared libraries if used",
+    "Always set DT_NEEDED for shared libraries (default)">;
+
+defm call_graph_ordering_file:
+  Eq<"call-graph-ordering-file", "Layout sections to optimize the given callgraph">;
 
 // -chroot doesn't have a help text because it is an internal option.
-defm chroot: Eq<"chroot">;
+def chroot: Separate<["--", "-"], "chroot">;
 
 def color_diagnostics: F<"color-diagnostics">,
-  HelpText<"Use colors in diagnostics">;
+  HelpText<"Alias for --color-diagnostics=always">;
 
 def color_diagnostics_eq: J<"color-diagnostics=">,
-  HelpText<"Use colors in diagnostics">;
+  HelpText<"Use colors in diagnostics">,
+  MetaVarName<"[auto,always,never]">;
+
+defm cref: B<"cref",
+    "Output cross reference table",
+    "Do not output cross reference table">;
 
-def define_common: F<"define-common">,
-  HelpText<"Assign space to common symbols">;
+defm define_common: B<"define-common",
+    "Assign space to common symbols",
+    "Do not assign space to common symbols">;
 
-def demangle: F<"demangle">, HelpText<"Demangle symbol names">;
+defm demangle: B<"demangle",
+    "Demangle symbol names (default)",
+    "Do not demangle symbol names">;
 
 def disable_new_dtags: F<"disable-new-dtags">,
   HelpText<"Disable new dynamic tags">;
@@ -76,158 +101,131 @@ def discard_locals: F<"discard-locals">,
 def discard_none: F<"discard-none">,
   HelpText<"Keep all symbols in the symbol table">;
 
-defm dynamic_linker: Eq<"dynamic-linker">,
-  HelpText<"Which dynamic linker to use">;
+defm dynamic_linker: Eq<"dynamic-linker", "Which dynamic linker to use">;
 
-defm dynamic_list: Eq<"dynamic-list">,
-  HelpText<"Read a list of dynamic symbols">;
+defm dynamic_list: Eq<"dynamic-list", "Read a list of dynamic symbols">;
 
-def eh_frame_hdr: F<"eh-frame-hdr">,
-  HelpText<"Request creation of .eh_frame_hdr section and PT_GNU_EH_FRAME segment header">;
+defm eh_frame_hdr: B<"eh-frame-hdr",
+    "Request creation of .eh_frame_hdr section and PT_GNU_EH_FRAME segment header",
+    "Do not create .eh_frame_hdr section">;
 
 def emit_relocs: F<"emit-relocs">, HelpText<"Generate relocations in output">;
 
 def enable_new_dtags: F<"enable-new-dtags">,
-  HelpText<"Enable new dynamic tags">;
+  HelpText<"Enable new dynamic tags (default)">;
+
+def end_group: F<"end-group">,
+  HelpText<"Ignored for compatibility with GNU unless you pass --warn-backrefs">;
 
 def end_lib: F<"end-lib">,
   HelpText<"End a grouping of objects that should be treated as if they were together in an archive">;
 
-defm entry: Eq<"entry">, HelpText<"Name of entry point symbol">,
+defm entry: Eq<"entry", "Name of entry point symbol">,
   MetaVarName<"<entry>">;
 
-defm error_limit: Eq<"error-limit">,
-  HelpText<"Maximum number of errors to emit before stopping (0 = no limit)">;
+defm error_limit:
+  Eq<"error-limit", "Maximum number of errors to emit before stopping (0 = no limit)">;
 
 def error_unresolved_symbols: F<"error-unresolved-symbols">,
   HelpText<"Report unresolved symbols as errors">;
 
-defm exclude_libs: Eq<"exclude-libs">,
-  HelpText<"Exclude static libraries from automatic export">;
+defm exclude_libs: Eq<"exclude-libs", "Exclude static libraries from automatic export">;
+
+defm execute_only: B<"execute-only",
+    "Do not mark executable sections readable",
+    "Mark executable sections readable (default)">;
 
-def export_dynamic: F<"export-dynamic">,
-  HelpText<"Put symbols in the dynamic symbol table">;
+defm export_dynamic: B<"export-dynamic",
+    "Put symbols in the dynamic symbol table",
+    "Do not put symbols in the dynamic symbol table (default)">;
 
-defm export_dynamic_symbol: Eq<"export-dynamic-symbol">,
-  HelpText<"Put a symbol in the dynamic symbol table">;
+defm export_dynamic_symbol:
+  Eq<"export-dynamic-symbol", "Put a symbol in the dynamic symbol table">;
 
-def fatal_warnings: F<"fatal-warnings">,
-  HelpText<"Treat warnings as errors">;
+defm fatal_warnings: B<"fatal-warnings",
+    "Treat warnings as errors",
+    "Do not treat warnings as errors (default)">;
 
-defm filter: Eq<"filter">,
-  HelpText<"Set DT_FILTER field to the specified name">;
+defm filter: Eq<"filter", "Set DT_FILTER field to the specified name">;
 
-defm fini: Eq<"fini">,
-  HelpText<"Specify a finalizer function">, MetaVarName<"<symbol>">;
+defm fini: Eq<"fini", "Specify a finalizer function">, MetaVarName<"<symbol>">;
 
 def fix_cortex_a53_843419: F<"fix-cortex-a53-843419">,
   HelpText<"Apply fixes for AArch64 Cortex-A53 erratum 843419">;
 
-def full_shutdown : F<"full-shutdown">,
-  HelpText<"Perform a full shutdown instead of calling _exit">;
+defm format: Eq<"format", "Change the input format of the inputs following this option">,
+  MetaVarName<"[default,elf,binary]">;
 
-defm format: Eq<"format">,
-  HelpText<"Change the input format of the inputs following this option">,
-  MetaVarName<"<input-format>">;
+defm gc_sections: B<"gc-sections",
+    "Enable garbage collection of unused sections",
+    "Disable garbage collection of unused sections (default)">;
 
-def gc_sections: F<"gc-sections">,
-  HelpText<"Enable garbage collection of unused sections">;
+defm gdb_index: B<"gdb-index",
+    "Generate .gdb_index section",
+    "Do not generate .gdb_index section (default)">;
 
-def gdb_index: F<"gdb-index">,
-  HelpText<"Generate .gdb_index section">;
+defm gnu_unique: B<"gnu-unique",
+  "Enable STB_GNU_UNIQUE symbol binding (default)",
+  "Disable STB_GNU_UNIQUE symbol binding">;
 
-defm hash_style: Eq<"hash-style">,
-  HelpText<"Specify hash style (sysv, gnu or both)">;
+defm hash_style: Eq<"hash-style", "Specify hash style (sysv, gnu or both)">;
 
 def help: F<"help">, HelpText<"Print option help">;
 
 def icf_all: F<"icf=all">, HelpText<"Enable identical code folding">;
 
-def icf_data: F<"icf-data">,
-  HelpText<"Enable ICF to also fold identical read only data">;
+def icf_safe: F<"icf=safe">, HelpText<"Enable safe identical code folding">;
+
+def icf_none: F<"icf=none">, HelpText<"Disable identical code folding (default)">;
 
-def icf_none: F<"icf=none">, HelpText<"Disable identical code folding">;
+defm ignore_function_address_equality: B<"ignore-function-address-equality",
+  "lld can break the address equality of functions",
+  "lld cannot break the address equality of functions">;
 
-defm image_base : Eq<"image-base">, HelpText<"Set the base address">;
+def ignore_data_address_equality: F<"ignore-data-address-equality">,
+  HelpText<"lld can break the address equality of data">;
 
-defm init: Eq<"init">, HelpText<"Specify an initializer function">,
+defm image_base: Eq<"image-base", "Set the base address">;
+
+defm init: Eq<"init", "Specify an initializer function">,
   MetaVarName<"<symbol>">;
 
-defm library: Eq<"library">, HelpText<"Root name of library to use">,
-  MetaVarName<"<libName>">;
+defm just_symbols: Eq<"just-symbols", "Just link symbols">;
 
-def lto_O: J<"lto-O">, MetaVarName<"<opt-level>">,
-  HelpText<"Optimization level for LTO">;
+defm keep_unique: Eq<"keep-unique", "Do not fold this symbol during ICF">;
+
+defm library: Eq<"library", "Root name of library to use">,
+  MetaVarName<"<libName>">;
 
 def m: JoinedOrSeparate<["-"], "m">, HelpText<"Set target emulation">;
 
-defm Map: Eq<"Map">, HelpText<"Print a link map to the specified file">;
+defm Map: Eq<"Map", "Print a link map to the specified file">;
 
-def merge_exidx_entries: F<"merge-exidx-entries">,
-  HelpText<"Enable merging .ARM.exidx entries">;
+defm merge_exidx_entries: B<"merge-exidx-entries",
+    "Enable merging .ARM.exidx entries (default)",
+    "Disable merging .ARM.exidx entries">;
 
 def nostdlib: F<"nostdlib">,
   HelpText<"Only search directories specified on the command line">;
 
-def no_as_needed: F<"no-as-needed">,
-  HelpText<"Always DT_NEEDED for shared libraries">;
-
 def no_color_diagnostics: F<"no-color-diagnostics">,
   HelpText<"Do not use colors in diagnostics">;
 
-def no_define_common: F<"no-define-common">,
-  HelpText<"Do not assign space to common symbols">;
-
-def no_demangle: F<"no-demangle">,
-  HelpText<"Do not demangle symbol names">;
-
 def no_dynamic_linker: F<"no-dynamic-linker">,
   HelpText<"Inhibit output of .interp section">;
 
-def no_eh_frame_hdr: F<"no-eh-frame-hdr">,
-  HelpText<"Do not create .eh_frame_hdr section">;
-
-def no_export_dynamic: F<"no-export-dynamic">;
-def no_fatal_warnings: F<"no-fatal-warnings">;
-
-def no_gc_sections: F<"no-gc-sections">,
-  HelpText<"Disable garbage collection of unused sections">;
-
-def no_gdb_index: F<"no-gdb-index">,
-  HelpText<"Do not generate .gdb_index section">;
-
-def no_gnu_unique: F<"no-gnu-unique">,
-  HelpText<"Disable STB_GNU_UNIQUE symbol binding">;
-
-def no_merge_exidx_entries: F<"no-merge-exidx-entries">,
-  HelpText<"Disable merging .ARM.exidx entries">;
-
-def no_threads: F<"no-threads">,
-  HelpText<"Do not run the linker multi-threaded">;
-
-def no_whole_archive: F<"no-whole-archive">,
-  HelpText<"Restores the default behavior of loading archive members">;
-
 def noinhibit_exec: F<"noinhibit-exec">,
   HelpText<"Retain the executable output file whenever it is still usable">;
 
-def nopie: F<"nopie">, HelpText<"Do not create a position independent executable">;
-
-def no_omagic: Flag<["--"], "no-omagic">, MetaVarName<"<magic>">,
+def no_omagic: F<"no-omagic">, MetaVarName<"<magic>">,
   HelpText<"Do not set the text data sections to be writable">;
 
-def no_print_gc_sections: F<"no-print-gc-sections">,
-  HelpText<"Do not list removed unused sections">;
-
 def no_rosegment: F<"no-rosegment">,
   HelpText<"Do not put read-only non-executable sections in their own segment">;
 
 def no_undefined: F<"no-undefined">,
   HelpText<"Report unresolved symbols even if the linker is creating a shared library">;
 
-def no_undefined_version: F<"no-undefined-version">,
-  HelpText<"Report version scripts that refer undefined symbols">;
-
 def o: JoinedOrSeparate<["-"], "o">, MetaVarName<"<path>">,
   HelpText<"Path to file to write output">;
 
@@ -237,42 +235,62 @@ def oformat: Separate<["--"], "oformat">, MetaVarName<"<format>">,
 def omagic: Flag<["--"], "omagic">, MetaVarName<"<magic>">,
   HelpText<"Set the text and data sections to be readable and writable">;
 
-defm orphan_handling: Eq<"orphan-handling">,
-  HelpText<"Control how orphan sections are handled when linker script used">;
+defm orphan_handling:
+  Eq<"orphan-handling", "Control how orphan sections are handled when linker script used">;
+
+defm pack_dyn_relocs:
+  Eq<"pack-dyn-relocs", "Pack dynamic relocations in the given format">,
+  MetaVarName<"[none,android,relr,android+relr]">;
+
+defm use_android_relr_tags: B<"use-android-relr-tags",
+    "Use SHT_ANDROID_RELR / DT_ANDROID_RELR* tags instead of SHT_RELR / DT_RELR*",
+    "Use SHT_RELR / DT_RELR* tags (default)">;
+
+defm pie: B<"pie",
+    "Create a position independent executable",
+    "Do not create a position independent executable (default)">;
+
+defm print_gc_sections: B<"print-gc-sections",
+    "List removed unused sections",
+    "Do not list removed unused sections (default)">;
 
-def pack_dyn_relocs_eq: J<"pack-dyn-relocs=">, MetaVarName<"<format>">,
-  HelpText<"Pack dynamic relocations in the given format (none or android)">;
+defm print_icf_sections: B<"print-icf-sections",
+    "List identical folded sections",
+    "Do not list identical folded sections (default)">;
 
-def pie: F<"pie">, HelpText<"Create a position independent executable">;
+def pop_state: F<"pop-state">,
+  HelpText<"Undo the effect of -push-state">;
 
-def print_gc_sections: F<"print-gc-sections">,
-  HelpText<"List removed unused sections">;
+def push_state: F<"push-state">,
+  HelpText<"Save the current state of -as-needed, -static and -whole-archive">;
 
 def print_map: F<"print-map">,
   HelpText<"Print a link map to the standard output">;
 
-defm reproduce: Eq<"reproduce">,
-  HelpText<"Dump linker invocation and input files for debugging">;
+defm reproduce: Eq<"reproduce", "Dump linker invocation and input files for debugging">;
 
-defm rpath: Eq<"rpath">, HelpText<"Add a DT_RUNPATH to the output">;
+defm rpath: Eq<"rpath", "Add a DT_RUNPATH to the output">;
 
 def relocatable: F<"relocatable">, HelpText<"Create relocatable object file">;
 
-defm retain_symbols_file: Eq<"retain-symbols-file">,
-  HelpText<"Retain only the symbols listed in the file">,
+defm retain_symbols_file:
+  Eq<"retain-symbols-file", "Retain only the symbols listed in the file">,
   MetaVarName<"<file>">;
 
-defm script: Eq<"script">, HelpText<"Read linker script">;
+defm script: Eq<"script", "Read linker script">;
 
-defm section_start: Eq<"section-start">, MetaVarName<"<address>">,
-  HelpText<"Set address of section">;
+defm section_start: Eq<"section-start", "Set address of section">,
+  MetaVarName<"<address>">;
 
 def shared: F<"shared">, HelpText<"Build a shared object">;
 
-defm soname: Eq<"soname">, HelpText<"Set DT_SONAME">;
+defm soname: Eq<"soname", "Set DT_SONAME">;
 
-defm sort_section: Eq<"sort-section">,
-  HelpText<"Specifies sections sorting rule when linkerscript is used">;
+defm sort_section:
+  Eq<"sort-section", "Specifies sections sorting rule when linkerscript is used">;
+
+def start_group: F<"start-group">,
+  HelpText<"Ignored for compatibility with GNU unless you pass --warn-backrefs">;
 
 def start_lib: F<"start-lib">,
   HelpText<"Start a grouping of objects that should be treated as if they were together in an archive">;
@@ -281,33 +299,39 @@ def strip_all: F<"strip-all">, HelpText<"Strip all symbols">;
 
 def strip_debug: F<"strip-debug">, HelpText<"Strip debugging information">;
 
-defm symbol_ordering_file: Eq<"symbol-ordering-file">,
-  HelpText<"Layout sections in the order specified by symbol file">;
+defm symbol_ordering_file:
+  Eq<"symbol-ordering-file", "Layout sections to place symbols in the order specified by symbol ordering file">;
 
-defm sysroot: Eq<"sysroot">, HelpText<"Set the system root">;
+defm sysroot: Eq<"sysroot", "Set the system root">;
 
 def target1_rel: F<"target1-rel">, HelpText<"Interpret R_ARM_TARGET1 as R_ARM_REL32">;
 
-def target1_abs: F<"target1-abs">, HelpText<"Interpret R_ARM_TARGET1 as R_ARM_ABS32">;
+def target1_abs: F<"target1-abs">, HelpText<"Interpret R_ARM_TARGET1 as R_ARM_ABS32 (default)">;
 
-defm target2: Eq<"target2">,
-  HelpText<"Interpret R_ARM_TARGET2 as <type>, where <type> is one of rel, abs, or got-rel">,
+defm target2:
+  Eq<"target2", "Interpret R_ARM_TARGET2 as <type>, where <type> is one of rel, abs, or got-rel">,
   MetaVarName<"<type>">;
 
-def threads: F<"threads">, HelpText<"Run the linker multi-threaded">;
+defm threads: B<"threads",
+    "Run the linker multi-threaded (default)",
+    "Do not run the linker multi-threaded">;
 
 def trace: F<"trace">, HelpText<"Print the names of the input files">;
 
-defm trace_symbol : Eq<"trace-symbol">, HelpText<"Trace references to symbols">;
+defm trace_symbol: Eq<"trace-symbol", "Trace references to symbols">;
+
+defm undefined: Eq<"undefined", "Force undefined symbol during linking">,
+  MetaVarName<"<symbol>">;
 
-defm undefined: Eq<"undefined">,
-  HelpText<"Force undefined symbol during linking">;
+defm unresolved_symbols:
+  Eq<"unresolved-symbols", "Determine how to handle unresolved symbols">;
 
-defm unresolved_symbols: Eq<"unresolved-symbols">,
-  HelpText<"Determine how to handle unresolved symbols">;
+defm undefined_version: B<"undefined-version",
+  "Allow unused version in version script (default)",
+  "Report version scripts that refer undefined symbols">;
 
-defm rsp_quoting: Eq<"rsp-quoting">,
-  HelpText<"Quoting style for response files. Values supported: windows|posix">;
+defm rsp_quoting: Eq<"rsp-quoting", "Quoting style for response files">,
+  MetaVarName<"[posix,windows]">;
 
 def v: Flag<["-"], "v">, HelpText<"Display the version number">;
 
@@ -315,91 +339,124 @@ def verbose: F<"verbose">, HelpText<"Verbose mode">;
 
 def version: F<"version">, HelpText<"Display the version number and exit">;
 
-defm version_script: Eq<"version-script">, HelpText<"Read a version script">;
+defm version_script: Eq<"version-script", "Read a version script">;
+
+defm warn_backrefs: B<"warn-backrefs",
+    "Warn about backward symbol references to fetch archive members",
+    "Do not warn about backward symbol references to fetch archive members (default)">;
+
+defm warn_common: B<"warn-common",
+    "Warn about duplicate common symbols",
+    "Do not warn about duplicate common symbols (default)">;
 
-def warn_common: F<"warn-common">,
-  HelpText<"Warn about duplicate common symbols">;
+defm warn_symbol_ordering: B<"warn-symbol-ordering",
+    "Warn about problems with the symbol ordering file (default)",
+    "Do not warn about problems with the symbol ordering file">;
 
 def warn_unresolved_symbols: F<"warn-unresolved-symbols">,
   HelpText<"Report unresolved symbols as warnings">;
 
-def whole_archive: F<"whole-archive">,
-  HelpText<"Force load of all members in a static library">;
+defm whole_archive: B<"whole-archive",
+    "Force load of all members in a static library",
+    "Do not force load of all members in a static library (default)">;
 
-defm wrap: Eq<"wrap">, HelpText<"Use wrapper functions for symbol">,
-  MetaVarName<"<symbol>">;
+defm wrap: Eq<"wrap", "Use wrapper functions for symbol">,
+  MetaVarName<"<symbol>=<symbol>">;
 
 def z: JoinedOrSeparate<["-"], "z">, MetaVarName<"<option>">,
   HelpText<"Linker option extensions">;
 
 // Aliases
-def alias_auxiliary: Separate<["-"], "f">, Alias<auxiliary>;
-def alias_Bdynamic_call_shared: F<"call_shared">, Alias<Bdynamic>;
-def alias_Bdynamic_dy: F<"dy">, Alias<Bdynamic>;
-def alias_Bstatic_dn: F<"dn">, Alias<Bstatic>;
-def alias_Bstatic_non_shared: F<"non_shared">, Alias<Bstatic>;
-def alias_Bstatic_static: F<"static">, Alias<Bstatic>;
-def alias_define_common_d: Flag<["-"], "d">, Alias<define_common>;
-def alias_define_common_dc: F<"dc">, Alias<define_common>;
-def alias_define_common_dp: F<"dp">, Alias<define_common>;
-def alias_discard_all_x: Flag<["-"], "x">, Alias<discard_all>;
-def alias_discard_locals_X: Flag<["-"], "X">, Alias<discard_locals>;
-def alias_emit_relocs: Flag<["-"], "q">, Alias<emit_relocs>;
-def alias_entry_e: JoinedOrSeparate<["-"], "e">, Alias<entry>;
-def alias_export_dynamic_E: Flag<["-"], "E">, Alias<export_dynamic>;
-def alias_filter: Separate<["-"], "F">, Alias<filter>;
-def alias_format_b: Separate<["-"], "b">, Alias<format>;
-def alias_library: JoinedOrSeparate<["-"], "l">, Alias<library>;
-def alias_library_path: JoinedOrSeparate<["-"], "L">, Alias<library_path>;
-def alias_omagic: Flag<["-"], "N">, Alias<omagic>;
-def alias_o_output: Joined<["--"], "output=">, Alias<o>;
-def alias_o_output2 : Separate<["--"], "output">, Alias<o>;
-def alias_pie_pic_executable: F<"pic-executable">, Alias<pie>;
-def alias_print_map_M: Flag<["-"], "M">, Alias<print_map>;
-def alias_relocatable_r: Flag<["-"], "r">, Alias<relocatable>;
-def alias_rpath_R: JoinedOrSeparate<["-"], "R">, Alias<rpath>;
-def alias_script_T: JoinedOrSeparate<["-"], "T">, Alias<script>;
-def alias_shared_Bshareable: F<"Bshareable">, Alias<shared>;
-def alias_soname_h: JoinedOrSeparate<["-"], "h">, Alias<soname>;
-def alias_strip_all: Flag<["-"], "s">, Alias<strip_all>;
-def alias_strip_debug_S: Flag<["-"], "S">, Alias<strip_debug>;
-def alias_trace: Flag<["-"], "t">, Alias<trace>;
-def alias_trace_symbol_y : JoinedOrSeparate<["-"], "y">, Alias<trace_symbol>;
-def alias_Ttext_segment: Separate<["-", "--"], "Ttext-segment">, Alias<Ttext>;
-def alias_Ttext_segment_eq: Joined<["-", "--"], "Ttext-segment=">, Alias<Ttext>;
-def alias_undefined_u: JoinedOrSeparate<["-"], "u">, Alias<undefined>;
-def alias_version_V: Flag<["-"], "V">, Alias<version>;
-
-// Our symbol resolution algorithm handles symbols in archive files differently
-// than traditional linkers, so we don't need --start-group and --end-group.
-// These options are recongized for compatibility but ignored.
-def end_group: F<"end-group">;
-def end_group_paren: Flag<["-"], ")">;
-def start_group: F<"start-group">;
-def start_group_paren: Flag<["-"], "(">;
+def: Separate<["-"], "f">, Alias<auxiliary>, HelpText<"Alias for --auxiliary">;
+def: F<"call_shared">, Alias<Bdynamic>, HelpText<"Alias for --Bdynamic">;
+def: F<"dy">, Alias<Bdynamic>, HelpText<"Alias for --Bdynamic">;
+def: F<"dn">, Alias<Bstatic>, HelpText<"Alias for --Bstatic">;
+def: F<"non_shared">, Alias<Bstatic>, HelpText<"Alias for --Bstatic">;
+def: F<"static">, Alias<Bstatic>, HelpText<"Alias for --Bstatic">;
+def: Flag<["-"], "d">, Alias<define_common>, HelpText<"Alias for --define-common">;
+def: F<"dc">, Alias<define_common>, HelpText<"Alias for --define-common">;
+def: F<"dp">, Alias<define_common>, HelpText<"Alias for --define-common">;
+def: Flag<["-"], "x">, Alias<discard_all>, HelpText<"Alias for --discard-all">;
+def: Flag<["-"], "X">, Alias<discard_locals>, HelpText<"Alias for --discard-locals">;
+def: Flag<["-"], "q">, Alias<emit_relocs>, HelpText<"Alias for --emit-relocs">;
+def: Flag<["-"], ")">, Alias<end_group>, HelpText<"Alias for --end-group">;
+def: JoinedOrSeparate<["-"], "e">, Alias<entry>, HelpText<"Alias for --entry">;
+def: Flag<["-"], "E">, Alias<export_dynamic>, HelpText<"Alias for --export-dynamic">;
+def: Separate<["-"], "F">, Alias<filter>, HelpText<"Alias for --filter">;
+def: Separate<["-"], "b">, Alias<format>, HelpText<"Alias for --format">;
+def: JoinedOrSeparate<["-"], "l">, Alias<library>, HelpText<"Alias for --library">;
+def: JoinedOrSeparate<["-"], "L">, Alias<library_path>, HelpText<"Alias for --library-path">;
+def: F<"nopie">, Alias<no_pie>, HelpText<"Alias for --no-pie">;
+def: F<"no-pic-executable">, Alias<no_pie>, HelpText<"Alias for --no-pie">;
+def: Flag<["-"], "N">, Alias<omagic>, HelpText<"Alias for --omagic">;
+def: Joined<["--"], "output=">, Alias<o>, HelpText<"Alias for -o">;
+def: Separate<["--"], "output">, Alias<o>, HelpText<"Alias for -o">;
+def: F<"pic-executable">, Alias<pie>, HelpText<"Alias for --pie">;
+def: Flag<["-"], "M">, Alias<print_map>, HelpText<"Alias for --print-map">;
+def: Flag<["-"], "r">, Alias<relocatable>, HelpText<"Alias for --relocatable">;
+def: JoinedOrSeparate<["-"], "R">, Alias<rpath>, HelpText<"Alias for --rpath">;
+def: JoinedOrSeparate<["-"], "T">, Alias<script>, HelpText<"Alias for --script">;
+def: F<"Bshareable">, Alias<shared>, HelpText<"Alias for --shared">;
+def: JoinedOrSeparate<["-"], "h">, Alias<soname>, HelpText<"Alias for --soname">;
+def: Flag<["-"], "(">, Alias<start_group>, HelpText<"Alias for --start-group">;
+def: Flag<["-"], "s">, Alias<strip_all>, HelpText<"Alias for --strip-all">;
+def: Flag<["-"], "S">, Alias<strip_debug>, HelpText<"Alias for --strip-debug">;
+def: Flag<["-"], "t">, Alias<trace>, HelpText<"Alias for --trace">;
+def: JoinedOrSeparate<["-"], "y">, Alias<trace_symbol>, HelpText<"Alias for --trace-symbol">;
+def: Separate<["-", "--"], "Ttext-segment">, Alias<Ttext>, HelpText<"Alias for --Ttext">;
+def: Joined<["-", "--"], "Ttext-segment=">, Alias<Ttext>, HelpText<"Alias for --Ttext">;
+def: JoinedOrSeparate<["-"], "u">, Alias<undefined>, HelpText<"Alias for --undefined">;
+def: Flag<["-"], "V">, Alias<version>, HelpText<"Alias for --version">;
 
 // LTO-related options.
 def lto_aa_pipeline: J<"lto-aa-pipeline=">,
   HelpText<"AA pipeline to run during LTO. Used in conjunction with -lto-newpm-passes">;
+def lto_debug_pass_manager: F<"lto-debug-pass-manager">,
+  HelpText<"Debug new pass manager">;
+def lto_new_pass_manager: F<"lto-new-pass-manager">,
+  HelpText<"Use new pass manager">;
 def lto_newpm_passes: J<"lto-newpm-passes=">,
   HelpText<"Passes to run during LTO">;
+def lto_O: J<"lto-O">, MetaVarName<"<opt-level>">,
+  HelpText<"Optimization level for LTO">;
 def lto_partitions: J<"lto-partitions=">,
   HelpText<"Number of LTO codegen partitions">;
+def lto_sample_profile: J<"lto-sample-profile=">,
+  HelpText<"Sample profile file path">;
 def disable_verify: F<"disable-verify">;
-defm mllvm: Eq<"mllvm">;
+defm mllvm: Eq<"mllvm", "Additional arguments to forward to LLVM's option processing">;
 def opt_remarks_filename: Separate<["--"], "opt-remarks-filename">,
   HelpText<"YAML output file for optimization remarks">;
 def opt_remarks_with_hotness: Flag<["--"], "opt-remarks-with-hotness">,
-  HelpText<"Include hotness informations in the optimization remarks file">;
-defm plugin_opt: Eq<"plugin-opt">,
-  HelpText<"specifies LTO options for compatibility with GNU linkers">;
+  HelpText<"Include hotness information in the optimization remarks file">;
+defm plugin_opt: Eq<"plugin-opt", "specifies LTO options for compatibility with GNU linkers">;
 def save_temps: F<"save-temps">;
 def thinlto_cache_dir: J<"thinlto-cache-dir=">,
   HelpText<"Path to ThinLTO cached object file directory">;
-defm thinlto_cache_policy: Eq<"thinlto-cache-policy">,
-  HelpText<"Pruning policy for the ThinLTO cache">;
+defm thinlto_cache_policy: Eq<"thinlto-cache-policy", "Pruning policy for the ThinLTO cache">;
 def thinlto_jobs: J<"thinlto-jobs=">, HelpText<"Number of ThinLTO jobs">;
 
+def: J<"plugin-opt=O">, Alias<lto_O>, HelpText<"Alias for -lto-O">;
+def: F<"plugin-opt=debug-pass-manager">,
+  Alias<lto_debug_pass_manager>, HelpText<"Alias for -lto-debug-pass-manager">;
+def: F<"plugin-opt=disable-verify">, Alias<disable_verify>, HelpText<"Alias for -disable-verify">;
+def plugin_opt_dwo_dir_eq: J<"plugin-opt=dwo_dir=">,
+  HelpText<"Directory to store .dwo files when LTO and debug fission are used">;
+def: J<"plugin-opt=jobs=">, Alias<thinlto_jobs>, HelpText<"Alias for -thinlto-jobs">;
+def: J<"plugin-opt=lto-partitions=">, Alias<lto_partitions>, HelpText<"Alias for -lto-partitions">;
+def plugin_opt_mcpu_eq: J<"plugin-opt=mcpu=">;
+def: F<"plugin-opt=new-pass-manager">,
+  Alias<lto_new_pass_manager>, HelpText<"Alias for -lto-new-pass-manager">;
+def plugin_opt_obj_path_eq: J<"plugin-opt=obj-path=">;
+def: J<"plugin-opt=sample-profile=">,
+  Alias<lto_sample_profile>, HelpText<"Alias for -lto-sample-profile">;
+def: F<"plugin-opt=save-temps">, Alias<save_temps>, HelpText<"Alias for -save-temps">;
+def plugin_opt_thinlto_emit_imports_files: F<"plugin-opt=thinlto-emit-imports-files">;
+def plugin_opt_thinlto_index_only: F<"plugin-opt=thinlto-index-only">;
+def plugin_opt_thinlto_index_only_eq: J<"plugin-opt=thinlto-index-only=">;
+def plugin_opt_thinlto_object_suffix_replace_eq: J<"plugin-opt=thinlto-object-suffix-replace=">;
+def plugin_opt_thinlto_prefix_replace_eq: J<"plugin-opt=thinlto-prefix-replace=">;
+
 // Ignore LTO plugin-related options.
 // clang -flto passes -plugin and -plugin-opt to the linker. This is required
 // for ld.gold and ld.bfd to get LTO working. But it's not for lld which doesn't
@@ -407,29 +464,38 @@ def thinlto_jobs: J<"thinlto-jobs=">, HelpText<"Number of ThinLTO jobs">;
 // just ignore the option on lld side as it's easier. In fact, the linker could
 // be called 'ld' and understanding which linker is used would require parsing of
 // --version output.
-defm plugin: Eq<"plugin">;
+defm plugin: Eq<"plugin", "Ignored for compatibility with GNU linkers">;
+
+def plugin_opt_fresolution_eq: J<"plugin-opt=-fresolution=">;
+def plugin_opt_pass_through_eq: J<"plugin-opt=-pass-through=">;
+def plugin_opt_thinlto: J<"plugin-opt=thinlto">;
+def plugin_opt_slash: J<"plugin-opt=/">;
 
 // Options listed below are silently ignored for now for compatibility.
-def allow_shlib_undefined: F<"allow-shlib-undefined">;
-def cref: F<"cref">;
-def detect_odr_violations: F<"detect-odr-violations">;
-def g: Flag<["-"], "g">;
-def long_plt: F<"long-plt">;
-def no_add_needed: F<"no-add-needed">;
-def no_allow_shlib_undefined: F<"no-allow-shlib-undefined">;
-def no_copy_dt_needed_entries: F<"no-copy-dt-needed-entries">;
-def no_ctors_in_init_array: F<"no-ctors-in-init-array">;
-def no_keep_memory: F<"no-keep-memory">;
-def no_mmap_output_file: F<"no-mmap-output-file">;
-def no_warn_common: F<"no-warn-common">;
-def no_warn_mismatch: F<"no-warn-mismatch">;
-defm rpath_link: Eq<"rpath-link">;
-def sort_common: F<"sort-common">;
-def stats: F<"stats">;
-def warn_execstack: F<"warn-execstack">;
-def warn_once: F<"warn-once">;
-def warn_shared_textrel: F<"warn-shared-textrel">;
-def EB : F<"EB">;
-def EL : F<"EL">;
-def G: JoinedOrSeparate<["-"], "G">;
-def Qy : F<"Qy">;
+def: F<"allow-shlib-undefined">;
+def: F<"detect-odr-violations">;
+def: Flag<["-"], "g">;
+def: F<"long-plt">;
+def: F<"no-add-needed">;
+def: F<"no-allow-shlib-undefined">;
+def: F<"no-copy-dt-needed-entries">;
+def: F<"no-ctors-in-init-array">;
+def: F<"no-keep-memory">;
+def: F<"no-mmap-output-file">;
+def: F<"no-warn-mismatch">;
+def: Separate<["--", "-"], "rpath-link">;
+def: J<"rpath-link=">;
+def: F<"sort-common">;
+def: F<"stats">;
+def: F<"warn-execstack">;
+def: F<"warn-once">;
+def: F<"warn-shared-textrel">;
+def: F<"EB">;
+def: F<"EL">;
+def: JoinedOrSeparate<["-"], "G">;
+def: F<"Qy">;
+
+// Hidden option used for testing MIPS multi-GOT implementation.
+defm mips_got_size:
+  Eq<"mips-got-size", "Max size of a single MIPS GOT. 0x10000 by default.">,
+  Flags<[HelpHidden]>;
diff --git a/gnu/llvm/tools/lld/ELF/OutputSections.cpp b/gnu/llvm/tools/lld/ELF/OutputSections.cpp
index 94c98284196..8253b18b486 100644
--- a/gnu/llvm/tools/lld/ELF/OutputSections.cpp
+++ b/gnu/llvm/tools/lld/ELF/OutputSections.cpp
@@ -10,11 +10,11 @@
 #include "OutputSections.h"
 #include "Config.h"
 #include "LinkerScript.h"
-#include "Strings.h"
 #include "SymbolTable.h"
 #include "SyntheticSections.h"
 #include "Target.h"
 #include "lld/Common/Memory.h"
+#include "lld/Common/Strings.h"
 #include "lld/Common/Threads.h"
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/Support/Compression.h"
@@ -25,15 +25,12 @@
 using namespace llvm;
 using namespace llvm::dwarf;
 using namespace llvm::object;
-using namespace llvm::support::endian;
 using namespace llvm::ELF;
 
 using namespace lld;
 using namespace lld::elf;
 
 uint8_t Out::First;
-OutputSection *Out::Opd;
-uint8_t *Out::OpdBuf;
 PhdrEntry *Out::TlsPhdr;
 OutputSection *Out::DebugInfo;
 OutputSection *Out::ElfHeader;
@@ -45,7 +42,9 @@ OutputSection *Out::FiniArray;
 std::vector<OutputSection *> elf::OutputSections;
 
 uint32_t OutputSection::getPhdrFlags() const {
-  uint32_t Ret = PF_R;
+  uint32_t Ret = 0;
+  if (Config->EMachine != EM_ARM || !(Flags & SHF_ARM_PURECODE))
+    Ret |= PF_R;
   if (Flags & SHF_WRITE)
     Ret |= PF_W;
   if (Flags & SHF_EXECINSTR)
@@ -70,9 +69,7 @@ void OutputSection::writeHeaderTo(typename ELFT::Shdr *Shdr) {
 OutputSection::OutputSection(StringRef Name, uint32_t Type, uint64_t Flags)
     : BaseCommand(OutputSectionKind),
       SectionBase(Output, Name, Flags, /*Entsize*/ 0, /*Alignment*/ 1, Type,
-                  /*Info*/ 0,
-                  /*Link*/ 0),
-      SectionIndex(INT_MAX) {
+                  /*Info*/ 0, /*Link*/ 0) {
   Live = false;
 }
 
@@ -91,13 +88,15 @@ static bool canMergeToProgbits(unsigned Type) {
 void OutputSection::addSection(InputSection *IS) {
   if (!Live) {
     // If IS is the first section to be added to this section,
-    // initialize Type and Entsize from IS.
+    // initialize Type, Entsize and flags from IS.
     Live = true;
     Type = IS->Type;
     Entsize = IS->Entsize;
+    Flags = IS->Flags;
   } else {
     // Otherwise, check if new type or flags are compatible with existing ones.
-    if ((Flags & (SHF_ALLOC | SHF_TLS)) != (IS->Flags & (SHF_ALLOC | SHF_TLS)))
+    unsigned Mask = SHF_ALLOC | SHF_TLS | SHF_LINK_ORDER;
+    if ((Flags & Mask) != (IS->Flags & Mask))
       error("incompatible section flags for " + Name + "\n>>> " + toString(IS) +
             ": 0x" + utohexstr(IS->Flags) + "\n>>> output section " + Name +
             ": 0x" + utohexstr(Flags));
@@ -114,9 +113,14 @@ void OutputSection::addSection(InputSection *IS) {
   }
 
   IS->Parent = this;
-  Flags |= IS->Flags;
+  uint64_t AndMask =
+      Config->EMachine == EM_ARM ? (uint64_t)SHF_ARM_PURECODE : 0;
+  uint64_t OrMask = ~AndMask;
+  uint64_t AndFlags = (Flags & IS->Flags) & AndMask;
+  uint64_t OrFlags = (Flags | IS->Flags) & OrMask;
+  Flags = AndFlags | OrFlags;
+
   Alignment = std::max(Alignment, IS->Alignment);
-  IS->OutSecOff = Size++;
 
   // If this section contains a table of fixed-size entries, sh_entsize
   // holds the element size. If it contains elements of different size we
@@ -134,8 +138,8 @@ void OutputSection::addSection(InputSection *IS) {
   }
 }
 
-void elf::sortByOrder(MutableArrayRef<InputSection *> In,
-                      std::function<int(InputSectionBase *S)> Order) {
+static void sortByOrder(MutableArrayRef<InputSection *> In,
+                        llvm::function_ref<int(InputSectionBase *S)> Order) {
   typedef std::pair<int, InputSection *> Pair;
   auto Comp = [](const Pair &A, const Pair &B) { return A.first < B.first; };
 
@@ -158,11 +162,11 @@ bool OutputSection::classof(const BaseCommand *C) {
   return C->Kind == OutputSectionKind;
 }
 
-void OutputSection::sort(std::function<int(InputSectionBase *S)> Order) {
+void OutputSection::sort(llvm::function_ref<int(InputSectionBase *S)> Order) {
   assert(Live);
-  assert(SectionCommands.size() == 1);
-  sortByOrder(cast<InputSectionDescription>(SectionCommands[0])->Sections,
-              Order);
+  for (BaseCommand *B : SectionCommands)
+    if (auto *ISD = dyn_cast<InputSectionDescription>(B))
+      sortByOrder(ISD->Sections, Order);
 }
 
 // Fill [Buf, Buf + Size) with Filler.
@@ -205,11 +209,11 @@ static void writeInt(uint8_t *Buf, uint64_t Data, uint64_t Size) {
   if (Size == 1)
     *Buf = Data;
   else if (Size == 2)
-    write16(Buf, Data, Config->Endianness);
+    write16(Buf, Data);
   else if (Size == 4)
-    write32(Buf, Data, Config->Endianness);
+    write32(Buf, Data);
   else if (Size == 8)
-    write64(Buf, Data, Config->Endianness);
+    write64(Buf, Data);
   else
     llvm_unreachable("unsupported Size argument");
 }
@@ -231,12 +235,7 @@ template <class ELFT> void OutputSection::writeTo(uint8_t *Buf) {
   }
 
   // Write leading padding.
-  std::vector<InputSection *> Sections;
-  for (BaseCommand *Cmd : SectionCommands)
-    if (auto *ISD = dyn_cast<InputSectionDescription>(Cmd))
-      for (InputSection *IS : ISD->Sections)
-        if (IS->Live)
-          Sections.push_back(IS);
+  std::vector<InputSection *> Sections = getInputSections(this);
   uint32_t Filler = getFiller();
   if (Filler)
     fill(Buf, Sections.empty() ? Size : Sections[0]->OutSecOff, Filler);
@@ -281,17 +280,13 @@ static void finalizeShtGroup(OutputSection *OS,
 }
 
 template <class ELFT> void OutputSection::finalize() {
-  InputSection *First = nullptr;
-  for (BaseCommand *Base : SectionCommands) {
-    if (auto *ISD = dyn_cast<InputSectionDescription>(Base)) {
-      if (ISD->Sections.empty())
-        continue;
-      if (First == nullptr)
-        First = ISD->Sections.front();
-    }
-    if (isa<ByteCommand>(Base) && Type == SHT_NOBITS)
-      Type = SHT_PROGBITS;
-  }
+  if (Type == SHT_NOBITS)
+    for (BaseCommand *Base : SectionCommands)
+      if (isa<ByteCommand>(Base))
+        Type = SHT_PROGBITS;
+
+  std::vector<InputSection *> V = getInputSections(this);
+  InputSection *First = V.empty() ? nullptr : V[0];
 
   if (Flags & SHF_LINK_ORDER) {
     // We must preserve the link order dependency of sections with the
@@ -367,8 +362,6 @@ static bool compCtors(const InputSection *A, const InputSection *B) {
   assert(Y.startswith(".ctors") || Y.startswith(".dtors"));
   X = X.substr(6);
   Y = Y.substr(6);
-  if (X.empty() && Y.empty())
-    return false;
   return X < Y;
 }
 
@@ -394,6 +387,14 @@ int elf::getPriority(StringRef S) {
   return V;
 }
 
+std::vector<InputSection *> elf::getInputSections(OutputSection *OS) {
+  std::vector<InputSection *> Ret;
+  for (BaseCommand *Base : OS->SectionCommands)
+    if (auto *ISD = dyn_cast<InputSectionDescription>(Base))
+      Ret.insert(Ret.end(), ISD->Sections.begin(), ISD->Sections.end());
+  return Ret;
+}
+
 // Sorts input sections by section name suffixes, so that .foo.N comes
 // before .foo.M if N < M. Used to sort .{init,fini}_array.N sections.
 // We want to keep the original order if the priorities are the same
diff --git a/gnu/llvm/tools/lld/ELF/Relocations.cpp b/gnu/llvm/tools/lld/ELF/Relocations.cpp
index abe5498ba51..467219ad054 100644
--- a/gnu/llvm/tools/lld/ELF/Relocations.cpp
+++ b/gnu/llvm/tools/lld/ELF/Relocations.cpp
@@ -45,14 +45,14 @@
 #include "Config.h"
 #include "LinkerScript.h"
 #include "OutputSections.h"
-#include "Strings.h"
 #include "SymbolTable.h"
 #include "Symbols.h"
 #include "SyntheticSections.h"
 #include "Target.h"
 #include "Thunks.h"
 #include "lld/Common/Memory.h"
-
+#include "lld/Common/Strings.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
@@ -80,55 +80,22 @@ static std::string getLocation(InputSectionBase &S, const Symbol &Sym,
   return Msg + S.getObjMsg(Off);
 }
 
-// This is a MIPS-specific rule.
-//
-// In case of MIPS GP-relative relocations always resolve to a definition
-// in a regular input file, ignoring the one-definition rule. So we,
-// for example, should not attempt to create a dynamic relocation even
-// if the target symbol is preemptible. There are two two MIPS GP-relative
-// relocations R_MIPS_GPREL16 and R_MIPS_GPREL32. But only R_MIPS_GPREL16
-// can be against a preemptible symbol.
-//
-// To get MIPS relocation type we apply 0xff mask. In case of O32 ABI all
-// relocation types occupy eight bit. In case of N64 ABI we extract first
-// relocation from 3-in-1 packet because only the first relocation can
-// be against a real symbol.
-static bool isMipsGprel(RelType Type) {
-  if (Config->EMachine != EM_MIPS)
-    return false;
-  Type &= 0xff;
-  return Type == R_MIPS_GPREL16 || Type == R_MICROMIPS_GPREL16 ||
-         Type == R_MICROMIPS_GPREL7_S2;
-}
-
 // This function is similar to the `handleTlsRelocation`. MIPS does not
 // support any relaxations for TLS relocations so by factoring out MIPS
 // handling in to the separate function we can simplify the code and do not
 // pollute other `handleTlsRelocation` by MIPS `ifs` statements.
 // Mips has a custom MipsGotSection that handles the writing of GOT entries
 // without dynamic relocations.
-template <class ELFT>
 static unsigned handleMipsTlsRelocation(RelType Type, Symbol &Sym,
                                         InputSectionBase &C, uint64_t Offset,
                                         int64_t Addend, RelExpr Expr) {
   if (Expr == R_MIPS_TLSLD) {
-    if (InX::MipsGot->addTlsIndex() && Config->Pic)
-      InX::RelaDyn->addReloc({Target->TlsModuleIndexRel, InX::MipsGot,
-                              InX::MipsGot->getTlsIndexOff(), false, nullptr,
-                              0});
+    InX::MipsGot->addTlsIndex(*C.File);
     C.Relocations.push_back({Expr, Type, Offset, Addend, &Sym});
     return 1;
   }
-
   if (Expr == R_MIPS_TLSGD) {
-    if (InX::MipsGot->addDynTlsEntry(Sym) && Sym.IsPreemptible) {
-      uint64_t Off = InX::MipsGot->getGlobalDynOffset(Sym);
-      InX::RelaDyn->addReloc(
-          {Target->TlsModuleIndexRel, InX::MipsGot, Off, false, &Sym, 0});
-      if (Sym.IsPreemptible)
-        InX::RelaDyn->addReloc({Target->TlsOffsetRel, InX::MipsGot,
-                                Off + Config->Wordsize, false, &Sym, 0});
-    }
+    InX::MipsGot->addDynTlsEntry(*C.File, Sym);
     C.Relocations.push_back({Expr, Type, Offset, Addend, &Sym});
     return 1;
   }
@@ -161,7 +128,7 @@ static unsigned handleARMTlsRelocation(RelType Type, Symbol &Sym,
 
   auto AddTlsReloc = [&](uint64_t Off, RelType Type, Symbol *Dest, bool Dyn) {
     if (Dyn)
-      InX::RelaDyn->addReloc({Type, InX::Got, Off, false, Dest, 0});
+      InX::RelaDyn->addReloc(Type, InX::Got, Off, Dest);
     else
       InX::Got->Relocations.push_back({R_ABS, Type, Off, 0, Dest});
   };
@@ -207,7 +174,7 @@ handleTlsRelocation(RelType Type, Symbol &Sym, InputSectionBase &C,
   if (Config->EMachine == EM_ARM)
     return handleARMTlsRelocation<ELFT>(Type, Sym, C, Offset, Addend, Expr);
   if (Config->EMachine == EM_MIPS)
-    return handleMipsTlsRelocation<ELFT>(Type, Sym, C, Offset, Addend, Expr);
+    return handleMipsTlsRelocation(Type, Sym, C, Offset, Addend, Expr);
 
   if (isRelExprOneOf<R_TLSDESC, R_TLSDESC_PAGE, R_TLSDESC_CALL>(Expr) &&
       Config->Shared) {
@@ -221,40 +188,62 @@ handleTlsRelocation(RelType Type, Symbol &Sym, InputSectionBase &C,
     return 1;
   }
 
-  if (isRelExprOneOf<R_TLSLD_PC, R_TLSLD>(Expr)) {
+  if (isRelExprOneOf<R_TLSLD_GOT, R_TLSLD_GOT_FROM_END, R_TLSLD_PC,
+                     R_TLSLD_HINT>(Expr)) {
     // Local-Dynamic relocs can be relaxed to Local-Exec.
     if (!Config->Shared) {
       C.Relocations.push_back(
-          {R_RELAX_TLS_LD_TO_LE, Type, Offset, Addend, &Sym});
-      return 2;
+          {Target->adjustRelaxExpr(Type, nullptr, R_RELAX_TLS_LD_TO_LE), Type,
+           Offset, Addend, &Sym});
+      return Target->TlsGdRelaxSkip;
     }
+    if (Expr == R_TLSLD_HINT)
+      return 1;
     if (InX::Got->addTlsIndex())
-      InX::RelaDyn->addReloc({Target->TlsModuleIndexRel, InX::Got,
-                              InX::Got->getTlsIndexOff(), false, nullptr, 0});
+      InX::RelaDyn->addReloc(Target->TlsModuleIndexRel, InX::Got,
+                             InX::Got->getTlsIndexOff(), nullptr);
     C.Relocations.push_back({Expr, Type, Offset, Addend, &Sym});
     return 1;
   }
 
   // Local-Dynamic relocs can be relaxed to Local-Exec.
-  if (isRelExprOneOf<R_ABS, R_TLSLD, R_TLSLD_PC>(Expr) && !Config->Shared) {
-    C.Relocations.push_back({R_RELAX_TLS_LD_TO_LE, Type, Offset, Addend, &Sym});
+  if (Expr == R_ABS && !Config->Shared) {
+    C.Relocations.push_back(
+        {Target->adjustRelaxExpr(Type, nullptr, R_RELAX_TLS_LD_TO_LE), Type,
+         Offset, Addend, &Sym});
     return 1;
   }
 
-  if (isRelExprOneOf<R_TLSDESC, R_TLSDESC_PAGE, R_TLSDESC_CALL, R_TLSGD,
-                     R_TLSGD_PC>(Expr)) {
+  // Local-Dynamic sequence where offset of tls variable relative to dynamic
+  // thread pointer is stored in the got.
+  if (Expr == R_TLSLD_GOT_OFF) {
+    // Local-Dynamic relocs can be relaxed to local-exec
+    if (!Config->Shared) {
+      C.Relocations.push_back({R_RELAX_TLS_LD_TO_LE, Type, Offset, Addend, &Sym});
+      return 1;
+    }
+    if (!Sym.isInGot()) {
+      InX::Got->addEntry(Sym);
+      uint64_t Off = Sym.getGotOffset();
+      InX::Got->Relocations.push_back({R_ABS, Target->TlsOffsetRel, Off, 0, &Sym});
+    }
+    C.Relocations.push_back({Expr, Type, Offset, Addend, &Sym});
+    return 1;
+  }
+
+  if (isRelExprOneOf<R_TLSDESC, R_TLSDESC_PAGE, R_TLSDESC_CALL, R_TLSGD_GOT,
+                     R_TLSGD_GOT_FROM_END, R_TLSGD_PC>(Expr)) {
     if (Config->Shared) {
       if (InX::Got->addDynTlsEntry(Sym)) {
         uint64_t Off = InX::Got->getGlobalDynOffset(Sym);
-        InX::RelaDyn->addReloc(
-            {Target->TlsModuleIndexRel, InX::Got, Off, false, &Sym, 0});
+        InX::RelaDyn->addReloc(Target->TlsModuleIndexRel, InX::Got, Off, &Sym);
 
         // If the symbol is preemptible we need the dynamic linker to write
         // the offset too.
         uint64_t OffsetOff = Off + Config->Wordsize;
         if (Sym.IsPreemptible)
-          InX::RelaDyn->addReloc(
-              {Target->TlsOffsetRel, InX::Got, OffsetOff, false, &Sym, 0});
+          InX::RelaDyn->addReloc(Target->TlsOffsetRel, InX::Got, OffsetOff,
+                                 &Sym);
         else
           InX::Got->Relocations.push_back(
               {R_ABS, Target->TlsOffsetRel, OffsetOff, 0, &Sym});
@@ -271,8 +260,8 @@ handleTlsRelocation(RelType Type, Symbol &Sym, InputSectionBase &C,
            Offset, Addend, &Sym});
       if (!Sym.isInGot()) {
         InX::Got->addEntry(Sym);
-        InX::RelaDyn->addReloc(
-            {Target->TlsGotRel, InX::Got, Sym.getGotOffset(), false, &Sym, 0});
+        InX::RelaDyn->addReloc(Target->TlsGotRel, InX::Got, Sym.getGotOffset(),
+                               &Sym);
       }
     } else {
       C.Relocations.push_back(
@@ -336,7 +325,7 @@ static bool isAbsoluteValue(const Symbol &Sym) {
 
 // Returns true if Expr refers a PLT entry.
 static bool needsPlt(RelExpr Expr) {
-  return isRelExprOneOf<R_PLT_PC, R_PPC_PLT_OPD, R_PLT, R_PLT_PAGE_PC>(Expr);
+  return isRelExprOneOf<R_PLT_PC, R_PPC_CALL_PLT, R_PLT, R_PLT_PAGE_PC>(Expr);
 }
 
 // Returns true if Expr refers a GOT entry. Note that this function
@@ -352,7 +341,8 @@ static bool needsGot(RelExpr Expr) {
 // file (PC, or GOT for example).
 static bool isRelExpr(RelExpr Expr) {
   return isRelExprOneOf<R_PC, R_GOTREL, R_GOTREL_FROM_END, R_MIPS_GOTREL,
-                        R_PAGE_PC, R_RELAX_GOT_PC>(Expr);
+                        R_PPC_CALL, R_PPC_CALL_PLT, R_PAGE_PC,
+                        R_RELAX_GOT_PC>(Expr);
 }
 
 // Returns true if a given relocation can be computed at link-time.
@@ -367,11 +357,13 @@ static bool isRelExpr(RelExpr Expr) {
 static bool isStaticLinkTimeConstant(RelExpr E, RelType Type, const Symbol &Sym,
                                      InputSectionBase &S, uint64_t RelOff) {
   // These expressions always compute a constant
-  if (isRelExprOneOf<R_GOT_FROM_END, R_GOT_OFF, R_MIPS_GOT_LOCAL_PAGE,
-                     R_MIPS_GOT_OFF, R_MIPS_GOT_OFF32, R_MIPS_GOT_GP_PC,
-                     R_MIPS_TLSGD, R_GOT_PAGE_PC, R_GOT_PC, R_GOTONLY_PC,
-                     R_GOTONLY_PC_FROM_END, R_PLT_PC, R_TLSGD_PC, R_TLSGD,
-                     R_PPC_PLT_OPD, R_TLSDESC_CALL, R_TLSDESC_PAGE, R_HINT>(E))
+  if (isRelExprOneOf<
+          R_GOT_FROM_END, R_GOT_OFF, R_TLSLD_GOT_OFF, R_MIPS_GOT_LOCAL_PAGE,
+          R_MIPS_GOTREL, R_MIPS_GOT_OFF, R_MIPS_GOT_OFF32, R_MIPS_GOT_GP_PC,
+          R_MIPS_TLSGD, R_GOT_PAGE_PC, R_GOT_PC, R_GOTONLY_PC,
+          R_GOTONLY_PC_FROM_END, R_PLT_PC, R_TLSGD_GOT, R_TLSGD_GOT_FROM_END,
+          R_TLSGD_PC, R_PPC_CALL_PLT, R_TLSDESC_CALL, R_TLSDESC_PAGE, R_HINT,
+          R_TLSLD_HINT>(E))
     return true;
 
   // These never do, except if the entire file is position dependent or if
@@ -417,39 +409,45 @@ static bool isStaticLinkTimeConstant(RelExpr E, RelType Type, const Symbol &Sym,
 }
 
 static RelExpr toPlt(RelExpr Expr) {
-  if (Expr == R_PPC_OPD)
-    return R_PPC_PLT_OPD;
-  if (Expr == R_PC)
+  switch (Expr) {
+  case R_PPC_CALL:
+    return R_PPC_CALL_PLT;
+  case R_PC:
     return R_PLT_PC;
-  if (Expr == R_PAGE_PC)
+  case R_PAGE_PC:
     return R_PLT_PAGE_PC;
-  if (Expr == R_ABS)
+  case R_ABS:
     return R_PLT;
-  return Expr;
+  default:
+    return Expr;
+  }
 }
 
 static RelExpr fromPlt(RelExpr Expr) {
   // We decided not to use a plt. Optimize a reference to the plt to a
   // reference to the symbol itself.
-  if (Expr == R_PLT_PC)
+  switch (Expr) {
+  case R_PLT_PC:
     return R_PC;
-  if (Expr == R_PPC_PLT_OPD)
-    return R_PPC_OPD;
-  if (Expr == R_PLT)
+  case R_PPC_CALL_PLT:
+    return R_PPC_CALL;
+  case R_PLT:
     return R_ABS;
-  return Expr;
+  default:
+    return Expr;
+  }
 }
 
 // Returns true if a given shared symbol is in a read-only segment in a DSO.
-template <class ELFT> static bool isReadOnly(SharedSymbol *SS) {
+template <class ELFT> static bool isReadOnly(SharedSymbol &SS) {
   typedef typename ELFT::Phdr Elf_Phdr;
 
   // Determine if the symbol is read-only by scanning the DSO's program headers.
-  const SharedFile<ELFT> &File = SS->getFile<ELFT>();
+  const SharedFile<ELFT> &File = SS.getFile<ELFT>();
   for (const Elf_Phdr &Phdr : check(File.getObj().program_headers()))
     if ((Phdr.p_type == ELF::PT_LOAD || Phdr.p_type == ELF::PT_GNU_RELRO) &&
-        !(Phdr.p_flags & ELF::PF_W) && SS->Value >= Phdr.p_vaddr &&
-        SS->Value < Phdr.p_vaddr + Phdr.p_memsz)
+        !(Phdr.p_flags & ELF::PF_W) && SS.Value >= Phdr.p_vaddr &&
+        SS.Value < Phdr.p_vaddr + Phdr.p_memsz)
       return true;
   return false;
 }
@@ -458,26 +456,45 @@ template <class ELFT> static bool isReadOnly(SharedSymbol *SS) {
 //
 // If two or more symbols are at the same offset, and at least one of
 // them are copied by a copy relocation, all of them need to be copied.
-// Otherwise, they would refer different places at runtime.
+// Otherwise, they would refer to different places at runtime.
 template <class ELFT>
-static std::vector<SharedSymbol *> getSymbolsAt(SharedSymbol *SS) {
+static SmallSet<SharedSymbol *, 4> getSymbolsAt(SharedSymbol &SS) {
   typedef typename ELFT::Sym Elf_Sym;
 
-  SharedFile<ELFT> &File = SS->getFile<ELFT>();
+  SharedFile<ELFT> &File = SS.getFile<ELFT>();
 
-  std::vector<SharedSymbol *> Ret;
+  SmallSet<SharedSymbol *, 4> Ret;
   for (const Elf_Sym &S : File.getGlobalELFSyms()) {
     if (S.st_shndx == SHN_UNDEF || S.st_shndx == SHN_ABS ||
-        S.st_value != SS->Value)
+        S.st_value != SS.Value)
       continue;
     StringRef Name = check(S.getName(File.getStringTable()));
     Symbol *Sym = Symtab->find(Name);
     if (auto *Alias = dyn_cast_or_null<SharedSymbol>(Sym))
-      Ret.push_back(Alias);
+      Ret.insert(Alias);
   }
   return Ret;
 }
 
+// When a symbol is copy relocated or we create a canonical plt entry, it is
+// effectively a defined symbol. In the case of copy relocation the symbol is
+// in .bss and in the case of a canonical plt entry it is in .plt. This function
+// replaces the existing symbol with a Defined pointing to the appropriate
+// location.
+static void replaceWithDefined(Symbol &Sym, SectionBase *Sec, uint64_t Value,
+                               uint64_t Size) {
+  Symbol Old = Sym;
+  replaceSymbol<Defined>(&Sym, Sym.File, Sym.getName(), Sym.Binding,
+                         Sym.StOther, Sym.Type, Value, Size, Sec);
+  Sym.PltIndex = Old.PltIndex;
+  Sym.GotIndex = Old.GotIndex;
+  Sym.VerdefIndex = Old.VerdefIndex;
+  Sym.IsPreemptible = true;
+  Sym.ExportDynamic = true;
+  Sym.IsUsedInRegularObj = true;
+  Sym.Used = true;
+}
+
 // Reserve space in .bss or .bss.rel.ro for copy relocation.
 //
 // The copy relocation is pretty much a hack. If you use a copy relocation
@@ -520,17 +537,17 @@ static std::vector<SharedSymbol *> getSymbolsAt(SharedSymbol *SS) {
 // to the variable in .bss. This kind of issue is sometimes very hard to
 // debug. What's a solution? Instead of exporting a varaible V from a DSO,
 // define an accessor getV().
-template <class ELFT> static void addCopyRelSymbol(SharedSymbol *SS) {
+template <class ELFT> static void addCopyRelSymbol(SharedSymbol &SS) {
   // Copy relocation against zero-sized symbol doesn't make sense.
-  uint64_t SymSize = SS->getSize();
-  if (SymSize == 0)
-    fatal("cannot create a copy relocation for symbol " + toString(*SS));
+  uint64_t SymSize = SS.getSize();
+  if (SymSize == 0 || SS.Alignment == 0)
+    fatal("cannot create a copy relocation for symbol " + toString(SS));
 
   // See if this symbol is in a read-only segment. If so, preserve the symbol's
   // memory protection by reserving space in the .bss.rel.ro section.
   bool IsReadOnly = isReadOnly<ELFT>(SS);
   BssSection *Sec = make<BssSection>(IsReadOnly ? ".bss.rel.ro" : ".bss",
-                                     SymSize, SS->Alignment);
+                                     SymSize, SS.Alignment);
   if (IsReadOnly)
     InX::BssRelRo->getParent()->addSection(Sec);
   else
@@ -539,126 +556,10 @@ template <class ELFT> static void addCopyRelSymbol(SharedSymbol *SS) {
   // Look through the DSO's dynamic symbol table for aliases and create a
   // dynamic symbol for each one. This causes the copy relocation to correctly
   // interpose any aliases.
-  for (SharedSymbol *Sym : getSymbolsAt<ELFT>(SS)) {
-    Sym->CopyRelSec = Sec;
-    Sym->IsPreemptible = false;
-    Sym->IsUsedInRegularObj = true;
-    Sym->Used = true;
-  }
+  for (SharedSymbol *Sym : getSymbolsAt<ELFT>(SS))
+    replaceWithDefined(*Sym, Sec, 0, Sym->Size);
 
-  InX::RelaDyn->addReloc({Target->CopyRel, Sec, 0, false, SS, 0});
-}
-
-static void errorOrWarn(const Twine &Msg) {
-  if (!Config->NoinhibitExec)
-    error(Msg);
-  else
-    warn(Msg);
-}
-
-// Returns PLT relocation expression.
-//
-// This handles a non PIC program call to function in a shared library. In
-// an ideal world, we could just report an error saying the relocation can
-// overflow at runtime. In the real world with glibc, crt1.o has a
-// R_X86_64_PC32 pointing to libc.so.
-//
-// The general idea on how to handle such cases is to create a PLT entry and
-// use that as the function value.
-//
-// For the static linking part, we just return a plt expr and everything
-// else will use the the PLT entry as the address.
-//
-// The remaining problem is making sure pointer equality still works. We
-// need the help of the dynamic linker for that. We let it know that we have
-// a direct reference to a so symbol by creating an undefined symbol with a
-// non zero st_value. Seeing that, the dynamic linker resolves the symbol to
-// the value of the symbol we created. This is true even for got entries, so
-// pointer equality is maintained. To avoid an infinite loop, the only entry
-// that points to the real function is a dedicated got entry used by the
-// plt. That is identified by special relocation types (R_X86_64_JUMP_SLOT,
-// R_386_JMP_SLOT, etc).
-static RelExpr getPltExpr(Symbol &Sym, RelExpr Expr, bool &IsConstant) {
-  Sym.NeedsPltAddr = true;
-  Sym.IsPreemptible = false;
-  IsConstant = true;
-  return toPlt(Expr);
-}
-
-// This modifies the expression if we can use a copy relocation or point the
-// symbol to the PLT.
-template <class ELFT>
-static RelExpr adjustExpr(Symbol &Sym, RelExpr Expr, RelType Type,
-                          InputSectionBase &S, uint64_t RelOff,
-                          bool &IsConstant) {
-  // If a relocation can be applied at link-time, we don't need to
-  // create a dynamic relocation in the first place.
-  if (IsConstant)
-    return Expr;
-
-  // We can create any dynamic relocation supported by the dynamic linker if a
-  // section is writable or we are passed -z notext.
-  bool CanWrite = (S.Flags & SHF_WRITE) || !Config->ZText;
-  if (CanWrite && Target->isPicRel(Type))
-    return Expr;
-
-  // If the relocation is to a weak undef, and we are producing
-  // executable, give up on it and produce a non preemptible 0.
-  if (!Config->Shared && Sym.isUndefWeak()) {
-    Sym.IsPreemptible = false;
-    IsConstant = true;
-    return Expr;
-  }
-
-  // If we got here we know that this relocation would require the dynamic
-  // linker to write a value to read only memory or use an unsupported
-  // relocation.
-
-  // We can hack around it if we are producing an executable and
-  // the refered symbol can be preemepted to refer to the executable.
-  if (!CanWrite && (Config->Shared || (Config->Pic && !isRelExpr(Expr)))) {
-    error(
-        "can't create dynamic relocation " + toString(Type) + " against " +
-        (Sym.getName().empty() ? "local symbol" : "symbol: " + toString(Sym)) +
-        " in readonly segment; recompile object files with -fPIC" +
-        getLocation(S, Sym, RelOff));
-    return Expr;
-  }
-
-  // Copy relocations are only possible if we are creating an executable and the
-  // symbol is shared.
-  if (!Sym.isShared() || Config->Shared)
-    return Expr;
-
-  if (Sym.getVisibility() != STV_DEFAULT &&
-      (Sym.getVisibility() != STV_PROTECTED || !Sym.isFunc())) {
-    error("cannot preempt symbol: " + toString(Sym) +
-          getLocation(S, Sym, RelOff));
-    return Expr;
-  }
-
-  if (Sym.isObject()) {
-    // Produce a copy relocation.
-    auto *B = dyn_cast<SharedSymbol>(&Sym);
-    if (B && !B->CopyRelSec) {
-      if (Config->ZNocopyreloc)
-        error("unresolvable relocation " + toString(Type) +
-              " against symbol '" + toString(*B) +
-              "'; recompile with -fPIC or remove '-z nocopyreloc'" +
-              getLocation(S, Sym, RelOff));
-
-      addCopyRelSymbol<ELFT>(B);
-    }
-    IsConstant = true;
-    return Expr;
-  }
-
-  if (Sym.isFunc())
-    return getPltExpr(Sym, Expr, IsConstant);
-
-  errorOrWarn("symbol '" + toString(Sym) + "' defined in " +
-              toString(Sym.File) + " has no type");
-  return Expr;
+  InX::RelaDyn->addReloc(Target->CopyRel, Sec, 0, &SS);
 }
 
 // MIPS has an odd notion of "paired" relocations to calculate addends.
@@ -733,7 +634,7 @@ static bool maybeReportUndefined(Symbol &Sym, InputSectionBase &Sec,
     return false;
 
   bool CanBeExternal =
-      Sym.computeBinding() != STB_LOCAL && Sym.getVisibility() == STV_DEFAULT;
+      Sym.computeBinding() != STB_LOCAL && Sym.Visibility == STV_DEFAULT;
   if (Config->UnresolvedSymbols == UnresolvedPolicy::Ignore && CanBeExternal)
     return false;
 
@@ -761,12 +662,12 @@ static bool maybeReportUndefined(Symbol &Sym, InputSectionBase &Sec,
 // this for the N32 ABI. Iterate over relocation with the same offset and put
 // theirs types into the single bit-set.
 template <class RelTy> static RelType getMipsN32RelType(RelTy *&Rel, RelTy *End) {
-  RelType Type = Rel->getType(Config->IsMips64EL);
+  RelType Type = 0;
   uint64_t Offset = Rel->r_offset;
 
   int N = 0;
-  while (Rel + 1 != End && (Rel + 1)->r_offset == Offset)
-    Type |= (++Rel)->getType(Config->IsMips64EL) << (8 * ++N);
+  while (Rel != End && Rel->r_offset == Offset)
+    Type |= (Rel++)->getType(Config->IsMips64EL) << (8 * N++);
   return Type;
 }
 
@@ -816,16 +717,34 @@ private:
 };
 } // namespace
 
+static void addRelativeReloc(InputSectionBase *IS, uint64_t OffsetInSec,
+                             Symbol *Sym, int64_t Addend, RelExpr Expr,
+                             RelType Type) {
+  // Add a relative relocation. If RelrDyn section is enabled, and the
+  // relocation offset is guaranteed to be even, add the relocation to
+  // the RelrDyn section, otherwise add it to the RelaDyn section.
+  // RelrDyn sections don't support odd offsets. Also, RelrDyn sections
+  // don't store the addend values, so we must write it to the relocated
+  // address.
+  if (InX::RelrDyn && IS->Alignment >= 2 && OffsetInSec % 2 == 0) {
+    IS->Relocations.push_back({Expr, Type, OffsetInSec, Addend, Sym});
+    InX::RelrDyn->Relocs.push_back({IS, OffsetInSec});
+    return;
+  }
+  InX::RelaDyn->addReloc(Target->RelativeRel, IS, OffsetInSec, Sym, Addend,
+                         Expr, Type);
+}
+
 template <class ELFT, class GotPltSection>
 static void addPltEntry(PltSection *Plt, GotPltSection *GotPlt,
-                        RelocationBaseSection *Rel, RelType Type, Symbol &Sym,
-                        bool UseSymVA) {
+                        RelocationBaseSection *Rel, RelType Type, Symbol &Sym) {
   Plt->addEntry<ELFT>(Sym);
   GotPlt->addEntry(Sym);
-  Rel->addReloc({Type, GotPlt, Sym.getGotPltOffset(), UseSymVA, &Sym, 0});
+  Rel->addReloc(
+      {Type, GotPlt, Sym.getGotPltOffset(), !Sym.IsPreemptible, &Sym, 0});
 }
 
-template <class ELFT> static void addGotEntry(Symbol &Sym, bool Preemptible) {
+template <class ELFT> static void addGotEntry(Symbol &Sym) {
   InX::Got->addEntry(Sym);
 
   RelExpr Expr = Sym.isTls() ? R_TLS : R_ABS;
@@ -838,7 +757,8 @@ template <class ELFT> static void addGotEntry(Symbol &Sym, bool Preemptible) {
   // add a static relocation to a Relocations vector so that
   // InputSection::relocate will do the work for us. We may be able
   // to just write a value now, but it is a TODO.)
-  bool IsLinkTimeConstant = !Preemptible && (!Config->Pic || isAbsolute(Sym));
+  bool IsLinkTimeConstant =
+      !Sym.IsPreemptible && (!Config->Pic || isAbsolute(Sym));
   if (IsLinkTimeConstant) {
     InX::Got->Relocations.push_back({Expr, Target->GotRel, Off, 0, &Sym});
     return;
@@ -846,23 +766,33 @@ template <class ELFT> static void addGotEntry(Symbol &Sym, bool Preemptible) {
 
   // Otherwise, we emit a dynamic relocation to .rel[a].dyn so that
   // the GOT slot will be fixed at load-time.
-  RelType Type;
-  if (Sym.isTls())
-    Type = Target->TlsGotRel;
-  else if (!Preemptible && Config->Pic && !isAbsolute(Sym))
-    Type = Target->RelativeRel;
-  else
-    Type = Target->GotRel;
-  InX::RelaDyn->addReloc({Type, InX::Got, Off, !Preemptible, &Sym, 0});
+  if (!Sym.isTls() && !Sym.IsPreemptible && Config->Pic && !isAbsolute(Sym)) {
+    addRelativeReloc(InX::Got, Off, &Sym, 0, R_ABS, Target->GotRel);
+    return;
+  }
+  InX::RelaDyn->addReloc(Sym.isTls() ? Target->TlsGotRel : Target->GotRel,
+                         InX::Got, Off, &Sym, 0,
+                         Sym.IsPreemptible ? R_ADDEND : R_ABS, Target->GotRel);
+}
 
-  // REL type relocations don't have addend fields unlike RELAs, and
-  // their addends are stored to the section to which they are applied.
-  // So, store addends if we need to.
-  //
-  // This is ugly -- the difference between REL and RELA should be
-  // handled in a better way. It's a TODO.
-  if (!Config->IsRela && !Preemptible)
-    InX::Got->Relocations.push_back({R_ABS, Target->GotRel, Off, 0, &Sym});
+// Return true if we can define a symbol in the executable that
+// contains the value/function of a symbol defined in a shared
+// library.
+static bool canDefineSymbolInExecutable(Symbol &Sym) {
+  // If the symbol has default visibility the symbol defined in the
+  // executable will preempt it.
+  // Note that we want the visibility of the shared symbol itself, not
+  // the visibility of the symbol in the output file we are producing. That is
+  // why we use Sym.StOther.
+  if ((Sym.StOther & 0x3) == STV_DEFAULT)
+    return true;
+
+  // If we are allowed to break address equality of functions, defining
+  // a plt entry will allow the program to call the function in the
+  // .so, but the .so and the executable will no agree on the address
+  // of the function. Similar logic for objects.
+  return ((Sym.isFunc() && Config->IgnoreFunctionAddressEquality) ||
+          (Sym.isObject() && Config->IgnoreDataAddressEquality));
 }
 
 // The reason we have to do this early scan is as follows
@@ -879,129 +809,23 @@ template <class ELFT> static void addGotEntry(Symbol &Sym, bool Preemptible) {
 // complicates things for the dynamic linker and means we would have to reserve
 // space for the extra PT_LOAD even if we end up not using it.
 template <class ELFT, class RelTy>
-static void scanRelocs(InputSectionBase &Sec, ArrayRef<RelTy> Rels) {
-  OffsetGetter GetOffset(Sec);
-
-  // Not all relocations end up in Sec.Relocations, but a lot do.
-  Sec.Relocations.reserve(Rels.size());
-
-  for (auto I = Rels.begin(), End = Rels.end(); I != End; ++I) {
-    const RelTy &Rel = *I;
-    Symbol &Sym = Sec.getFile<ELFT>()->getRelocTargetSym(Rel);
-    RelType Type = Rel.getType(Config->IsMips64EL);
-
-    // Deal with MIPS oddity.
-    if (Config->MipsN32Abi)
-      Type = getMipsN32RelType(I, End);
-
-    // Get an offset in an output section this relocation is applied to.
-    uint64_t Offset = GetOffset.get(Rel.r_offset);
-    if (Offset == uint64_t(-1))
-      continue;
-
-    // Skip if the target symbol is an erroneous undefined symbol.
-    if (maybeReportUndefined(Sym, Sec, Rel.r_offset))
-      continue;
-
-    RelExpr Expr =
-        Target->getRelExpr(Type, Sym, Sec.Data.begin() + Rel.r_offset);
-
-    // Ignore "hint" relocations because they are only markers for relaxation.
-    if (isRelExprOneOf<R_HINT, R_NONE>(Expr))
-      continue;
-
-    // Handle yet another MIPS-ness.
-    if (isMipsGprel(Type)) {
-      int64_t Addend = computeAddend<ELFT>(Rel, End, Sec, Expr, Sym.isLocal());
-      Sec.Relocations.push_back({R_MIPS_GOTREL, Type, Offset, Addend, &Sym});
-      continue;
-    }
-
-    bool Preemptible = Sym.IsPreemptible;
-
-    // Strenghten or relax a PLT access.
-    //
-    // GNU ifunc symbols must be accessed via PLT because their addresses
-    // are determined by runtime.
-    //
-    // On the other hand, if we know that a PLT entry will be resolved within
-    // the same ELF module, we can skip PLT access and directly jump to the
-    // destination function. For example, if we are linking a main exectuable,
-    // all dynamic symbols that can be resolved within the executable will
-    // actually be resolved that way at runtime, because the main exectuable
-    // is always at the beginning of a search list. We can leverage that fact.
-    if (Sym.isGnuIFunc())
-      Expr = toPlt(Expr);
-    else if (!Preemptible && Expr == R_GOT_PC && !isAbsoluteValue(Sym))
-      Expr =
-          Target->adjustRelaxExpr(Type, Sec.Data.data() + Rel.r_offset, Expr);
-    else if (!Preemptible)
-      Expr = fromPlt(Expr);
-
-    bool IsConstant =
-        isStaticLinkTimeConstant(Expr, Type, Sym, Sec, Rel.r_offset);
-
-    Expr = adjustExpr<ELFT>(Sym, Expr, Type, Sec, Rel.r_offset, IsConstant);
-    if (errorCount())
-      continue;
-
-    // This relocation does not require got entry, but it is relative to got and
-    // needs it to be created. Here we request for that.
-    if (isRelExprOneOf<R_GOTONLY_PC, R_GOTONLY_PC_FROM_END, R_GOTREL,
-                       R_GOTREL_FROM_END, R_PPC_TOC>(Expr))
-      InX::Got->HasGotOffRel = true;
-
-    // Read an addend.
-    int64_t Addend = computeAddend<ELFT>(Rel, End, Sec, Expr, Sym.isLocal());
-
-    // Process some TLS relocations, including relaxing TLS relocations.
-    // Note that this function does not handle all TLS relocations.
-    if (unsigned Processed =
-            handleTlsRelocation<ELFT>(Type, Sym, Sec, Offset, Addend, Expr)) {
-      I += (Processed - 1);
-      continue;
-    }
-
-    // If a relocation needs PLT, we create PLT and GOTPLT slots for the symbol.
-    if (needsPlt(Expr) && !Sym.isInPlt()) {
-      if (Sym.isGnuIFunc() && !Preemptible)
-        addPltEntry<ELFT>(InX::Iplt, InX::IgotPlt, InX::RelaIplt,
-                          Target->IRelativeRel, Sym, true);
-      else
-        addPltEntry<ELFT>(InX::Plt, InX::GotPlt, InX::RelaPlt, Target->PltRel,
-                          Sym, !Preemptible);
-    }
-
-    // Create a GOT slot if a relocation needs GOT.
-    if (needsGot(Expr)) {
-      if (Config->EMachine == EM_MIPS) {
-        // MIPS ABI has special rules to process GOT entries and doesn't
-        // require relocation entries for them. A special case is TLS
-        // relocations. In that case dynamic loader applies dynamic
-        // relocations to initialize TLS GOT entries.
-        // See "Global Offset Table" in Chapter 5 in the following document
-        // for detailed description:
-        // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
-        InX::MipsGot->addEntry(Sym, Addend, Expr);
-        if (Sym.isTls() && Sym.IsPreemptible)
-          InX::RelaDyn->addReloc({Target->TlsGotRel, InX::MipsGot,
-                                  Sym.getGotOffset(), false, &Sym, 0});
-      } else if (!Sym.isInGot()) {
-        addGotEntry<ELFT>(Sym, Preemptible);
-      }
-    }
-
-    if (!needsPlt(Expr) && !needsGot(Expr) && Sym.IsPreemptible) {
-      // We don't know anything about the finaly symbol. Just ask the dynamic
-      // linker to handle the relocation for us.
-      if (!Target->isPicRel(Type))
-        errorOrWarn(
-            "relocation " + toString(Type) +
-            " cannot be used against shared object; recompile with -fPIC" +
-            getLocation(Sec, Sym, Offset));
+static void processRelocAux(InputSectionBase &Sec, RelExpr Expr, RelType Type,
+                            uint64_t Offset, Symbol &Sym, const RelTy &Rel,
+                            int64_t Addend) {
+  if (isStaticLinkTimeConstant(Expr, Type, Sym, Sec, Offset)) {
+    Sec.Relocations.push_back({Expr, Type, Offset, Addend, &Sym});
+    return;
+  }
+  bool CanWrite = (Sec.Flags & SHF_WRITE) || !Config->ZText;
+  if (CanWrite) {
+    // R_GOT refers to a position in the got, even if the symbol is preemptible.
+    bool IsPreemptibleValue = Sym.IsPreemptible && Expr != R_GOT;
 
-      InX::RelaDyn->addReloc(
-          {Target->getDynRel(Type), &Sec, Offset, false, &Sym, Addend});
+    if (!IsPreemptibleValue) {
+      addRelativeReloc(&Sec, Offset, &Sym, Addend, Expr, Type);
+      return;
+    } else if (RelType Rel = Target->getDynRel(Type)) {
+      InX::RelaDyn->addReloc(Rel, &Sec, Offset, &Sym, Addend, R_ADDEND, Type);
 
       // MIPS ABI turns using of GOT and dynamic relocations inside out.
       // While regular ABI uses dynamic relocations to fill up GOT entries
@@ -1019,37 +843,210 @@ static void scanRelocs(InputSectionBase &Sec, ArrayRef<RelTy> Rels) {
       // a dynamic relocation.
       // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf p.4-19
       if (Config->EMachine == EM_MIPS)
-        InX::MipsGot->addEntry(Sym, Addend, Expr);
-      continue;
+        InX::MipsGot->addEntry(*Sec.File, Sym, Addend, Expr);
+      return;
     }
+  }
 
-    // The size is not going to change, so we fold it in here.
-    if (Expr == R_SIZE)
-      Addend += Sym.getSize();
+  // If the relocation is to a weak undef, and we are producing
+  // executable, give up on it and produce a non preemptible 0.
+  if (!Config->Shared && Sym.isUndefWeak()) {
+    Sec.Relocations.push_back({Expr, Type, Offset, Addend, &Sym});
+    return;
+  }
 
-    // If the produced value is a constant, we just remember to write it
-    // when outputting this section. We also have to do it if the format
-    // uses Elf_Rel, since in that case the written value is the addend.
-    if (IsConstant) {
-      Sec.Relocations.push_back({Expr, Type, Offset, Addend, &Sym});
-      continue;
+  if (!CanWrite && (Config->Pic && !isRelExpr(Expr))) {
+    error(
+        "can't create dynamic relocation " + toString(Type) + " against " +
+        (Sym.getName().empty() ? "local symbol" : "symbol: " + toString(Sym)) +
+        " in readonly segment; recompile object files with -fPIC "
+        "or pass '-Wl,-z,notext' to allow text relocations in the output" +
+        getLocation(Sec, Sym, Offset));
+    return;
+  }
+
+  // Copy relocations are only possible if we are creating an executable.
+  if (Config->Shared) {
+    errorOrWarn("relocation " + toString(Type) +
+                " cannot be used against symbol " + toString(Sym) +
+                "; recompile with -fPIC" + getLocation(Sec, Sym, Offset));
+    return;
+  }
+
+  // If the symbol is undefined we already reported any relevant errors.
+  if (Sym.isUndefined())
+    return;
+
+  if (!canDefineSymbolInExecutable(Sym)) {
+    error("cannot preempt symbol: " + toString(Sym) +
+          getLocation(Sec, Sym, Offset));
+    return;
+  }
+
+  if (Sym.isObject()) {
+    // Produce a copy relocation.
+    if (auto *SS = dyn_cast<SharedSymbol>(&Sym)) {
+      if (!Config->ZCopyreloc)
+        error("unresolvable relocation " + toString(Type) +
+              " against symbol '" + toString(*SS) +
+              "'; recompile with -fPIC or remove '-z nocopyreloc'" +
+              getLocation(Sec, Sym, Offset));
+      addCopyRelSymbol<ELFT>(*SS);
     }
+    Sec.Relocations.push_back({Expr, Type, Offset, Addend, &Sym});
+    return;
+  }
 
-    // If the output being produced is position independent, the final value
-    // is still not known. In that case we still need some help from the
-    // dynamic linker. We can however do better than just copying the incoming
-    // relocation. We can process some of it and and just ask the dynamic
-    // linker to add the load address.
-    if (Config->IsRela) {
-      InX::RelaDyn->addReloc(
-          {Target->RelativeRel, &Sec, Offset, true, &Sym, Addend});
-    } else {
-      // In REL, addends are stored to the target section.
-      InX::RelaDyn->addReloc(
-          {Target->RelativeRel, &Sec, Offset, true, &Sym, 0});
-      Sec.Relocations.push_back({Expr, Type, Offset, Addend, &Sym});
+  if (Sym.isFunc()) {
+    // This handles a non PIC program call to function in a shared library. In
+    // an ideal world, we could just report an error saying the relocation can
+    // overflow at runtime. In the real world with glibc, crt1.o has a
+    // R_X86_64_PC32 pointing to libc.so.
+    //
+    // The general idea on how to handle such cases is to create a PLT entry and
+    // use that as the function value.
+    //
+    // For the static linking part, we just return a plt expr and everything
+    // else will use the PLT entry as the address.
+    //
+    // The remaining problem is making sure pointer equality still works. We
+    // need the help of the dynamic linker for that. We let it know that we have
+    // a direct reference to a so symbol by creating an undefined symbol with a
+    // non zero st_value. Seeing that, the dynamic linker resolves the symbol to
+    // the value of the symbol we created. This is true even for got entries, so
+    // pointer equality is maintained. To avoid an infinite loop, the only entry
+    // that points to the real function is a dedicated got entry used by the
+    // plt. That is identified by special relocation types (R_X86_64_JUMP_SLOT,
+    // R_386_JMP_SLOT, etc).
+
+    // For position independent executable on i386, the plt entry requires ebx
+    // to be set. This causes two problems:
+    // * If some code has a direct reference to a function, it was probably
+    //   compiled without -fPIE/-fPIC and doesn't maintain ebx.
+    // * If a library definition gets preempted to the executable, it will have
+    //   the wrong ebx value.
+    if (Config->Pie && Config->EMachine == EM_386)
+      errorOrWarn("symbol '" + toString(Sym) +
+                  "' cannot be preempted; recompile with -fPIE" +
+                  getLocation(Sec, Sym, Offset));
+    if (!Sym.isInPlt())
+      addPltEntry<ELFT>(InX::Plt, InX::GotPlt, InX::RelaPlt, Target->PltRel,
+                        Sym);
+    if (!Sym.isDefined())
+      replaceWithDefined(Sym, InX::Plt, Sym.getPltOffset(), 0);
+    Sym.NeedsPltAddr = true;
+    Sec.Relocations.push_back({Expr, Type, Offset, Addend, &Sym});
+    return;
+  }
+
+  errorOrWarn("symbol '" + toString(Sym) + "' has no type" +
+              getLocation(Sec, Sym, Offset));
+}
+
+template <class ELFT, class RelTy>
+static void scanReloc(InputSectionBase &Sec, OffsetGetter &GetOffset, RelTy *&I,
+                      RelTy *End) {
+  const RelTy &Rel = *I;
+  Symbol &Sym = Sec.getFile<ELFT>()->getRelocTargetSym(Rel);
+  RelType Type;
+
+  // Deal with MIPS oddity.
+  if (Config->MipsN32Abi) {
+    Type = getMipsN32RelType(I, End);
+  } else {
+    Type = Rel.getType(Config->IsMips64EL);
+    ++I;
+  }
+
+  // Get an offset in an output section this relocation is applied to.
+  uint64_t Offset = GetOffset.get(Rel.r_offset);
+  if (Offset == uint64_t(-1))
+    return;
+
+  // Skip if the target symbol is an erroneous undefined symbol.
+  if (maybeReportUndefined(Sym, Sec, Rel.r_offset))
+    return;
+
+  const uint8_t *RelocatedAddr = Sec.Data.begin() + Rel.r_offset;
+  RelExpr Expr = Target->getRelExpr(Type, Sym, RelocatedAddr);
+
+  // Ignore "hint" relocations because they are only markers for relaxation.
+  if (isRelExprOneOf<R_HINT, R_NONE>(Expr))
+    return;
+
+  // Strenghten or relax relocations.
+  //
+  // GNU ifunc symbols must be accessed via PLT because their addresses
+  // are determined by runtime.
+  //
+  // On the other hand, if we know that a PLT entry will be resolved within
+  // the same ELF module, we can skip PLT access and directly jump to the
+  // destination function. For example, if we are linking a main exectuable,
+  // all dynamic symbols that can be resolved within the executable will
+  // actually be resolved that way at runtime, because the main exectuable
+  // is always at the beginning of a search list. We can leverage that fact.
+  if (Sym.isGnuIFunc())
+    Expr = toPlt(Expr);
+  else if (!Sym.IsPreemptible && Expr == R_GOT_PC && !isAbsoluteValue(Sym))
+    Expr = Target->adjustRelaxExpr(Type, RelocatedAddr, Expr);
+  else if (!Sym.IsPreemptible)
+    Expr = fromPlt(Expr);
+
+  // This relocation does not require got entry, but it is relative to got and
+  // needs it to be created. Here we request for that.
+  if (isRelExprOneOf<R_GOTONLY_PC, R_GOTONLY_PC_FROM_END, R_GOTREL,
+                     R_GOTREL_FROM_END, R_PPC_TOC>(Expr))
+    InX::Got->HasGotOffRel = true;
+
+  // Read an addend.
+  int64_t Addend = computeAddend<ELFT>(Rel, End, Sec, Expr, Sym.isLocal());
+
+  // Process some TLS relocations, including relaxing TLS relocations.
+  // Note that this function does not handle all TLS relocations.
+  if (unsigned Processed =
+          handleTlsRelocation<ELFT>(Type, Sym, Sec, Offset, Addend, Expr)) {
+    I += (Processed - 1);
+    return;
+  }
+
+  // If a relocation needs PLT, we create PLT and GOTPLT slots for the symbol.
+  if (needsPlt(Expr) && !Sym.isInPlt()) {
+    if (Sym.isGnuIFunc() && !Sym.IsPreemptible)
+      addPltEntry<ELFT>(InX::Iplt, InX::IgotPlt, InX::RelaIplt,
+                        Target->IRelativeRel, Sym);
+    else
+      addPltEntry<ELFT>(InX::Plt, InX::GotPlt, InX::RelaPlt, Target->PltRel,
+                        Sym);
+  }
+
+  // Create a GOT slot if a relocation needs GOT.
+  if (needsGot(Expr)) {
+    if (Config->EMachine == EM_MIPS) {
+      // MIPS ABI has special rules to process GOT entries and doesn't
+      // require relocation entries for them. A special case is TLS
+      // relocations. In that case dynamic loader applies dynamic
+      // relocations to initialize TLS GOT entries.
+      // See "Global Offset Table" in Chapter 5 in the following document
+      // for detailed description:
+      // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
+      InX::MipsGot->addEntry(*Sec.File, Sym, Addend, Expr);
+    } else if (!Sym.isInGot()) {
+      addGotEntry<ELFT>(Sym);
     }
   }
+
+  processRelocAux<ELFT>(Sec, Expr, Type, Offset, Sym, Rel, Addend);
+}
+
+template <class ELFT, class RelTy>
+static void scanRelocs(InputSectionBase &Sec, ArrayRef<RelTy> Rels) {
+  OffsetGetter GetOffset(Sec);
+
+  // Not all relocations end up in Sec.Relocations, but a lot do.
+  Sec.Relocations.reserve(Rels.size());
+
+  for (auto I = Rels.begin(), End = Rels.end(); I != End;)
+    scanReloc<ELFT>(Sec, GetOffset, I, End);
 }
 
 template <class ELFT> void elf::scanRelocations(InputSectionBase &S) {
@@ -1264,17 +1261,30 @@ ThunkSection *ThunkCreator::getISThunkSec(InputSection *IS) {
 //
 // We follow a simple but conservative heuristic to place ThunkSections at
 // offsets that are multiples of a Target specific branch range.
-// For an InputSectionRange that is smaller than the range, a single
+// For an InputSectionDescription that is smaller than the range, a single
 // ThunkSection at the end of the range will do.
+//
+// For an InputSectionDescription that is more than twice the size of the range,
+// we place the last ThunkSection at range bytes from the end of the
+// InputSectionDescription in order to increase the likelihood that the
+// distance from a thunk to its target will be sufficiently small to
+// allow for the creation of a short thunk.
 void ThunkCreator::createInitialThunkSections(
     ArrayRef<OutputSection *> OutputSections) {
   forEachInputSectionDescription(
       OutputSections, [&](OutputSection *OS, InputSectionDescription *ISD) {
         if (ISD->Sections.empty())
           return;
+        uint32_t ISDBegin = ISD->Sections.front()->OutSecOff;
+        uint32_t ISDEnd =
+            ISD->Sections.back()->OutSecOff + ISD->Sections.back()->getSize();
+        uint32_t LastThunkLowerBound = -1;
+        if (ISDEnd - ISDBegin > Target->ThunkSectionSpacing * 2)
+          LastThunkLowerBound = ISDEnd - Target->ThunkSectionSpacing;
+
         uint32_t ISLimit;
-        uint32_t PrevISLimit = ISD->Sections.front()->OutSecOff;
-        uint32_t ThunkUpperBound = PrevISLimit + Target->ThunkSectionSpacing;
+        uint32_t PrevISLimit = ISDBegin;
+        uint32_t ThunkUpperBound = ISDBegin + Target->ThunkSectionSpacing;
 
         for (const InputSection *IS : ISD->Sections) {
           ISLimit = IS->OutSecOff + IS->getSize();
@@ -1282,6 +1292,8 @@ void ThunkCreator::createInitialThunkSections(
             addThunkSection(OS, ISD, PrevISLimit);
             ThunkUpperBound = PrevISLimit + Target->ThunkSectionSpacing;
           }
+          if (ISLimit > LastThunkLowerBound)
+            break;
           PrevISLimit = ISLimit;
         }
         addThunkSection(OS, ISD, ISLimit);
@@ -1298,17 +1310,22 @@ ThunkSection *ThunkCreator::addThunkSection(OutputSection *OS,
 
 std::pair<Thunk *, bool> ThunkCreator::getThunk(Symbol &Sym, RelType Type,
                                                 uint64_t Src) {
-  auto Res = ThunkedSymbols.insert({&Sym, std::vector<Thunk *>()});
-  if (!Res.second) {
-    // Check existing Thunks for Sym to see if they can be reused
-    for (Thunk *ET : Res.first->second)
-      if (ET->isCompatibleWith(Type) &&
-          Target->inBranchRange(Type, Src, ET->ThunkSym->getVA()))
-        return std::make_pair(ET, false);
-  }
+  std::vector<Thunk *> *ThunkVec = nullptr;
+  // We use (section, offset) pair to find the thunk position if possible so
+  // that we create only one thunk for aliased symbols or ICFed sections.
+  if (auto *D = dyn_cast<Defined>(&Sym))
+    if (!D->isInPlt() && D->Section)
+      ThunkVec = &ThunkedSymbolsBySection[{D->Section->Repl, D->Value}];
+  if (!ThunkVec)
+    ThunkVec = &ThunkedSymbols[&Sym];
+  // Check existing Thunks for Sym to see if they can be reused
+  for (Thunk *ET : *ThunkVec)
+    if (ET->isCompatibleWith(Type) &&
+        Target->inBranchRange(Type, Src, ET->getThunkTargetSym()->getVA()))
+      return std::make_pair(ET, false);
   // No existing compatible Thunk in range, create a new one
   Thunk *T = addThunk(Type, Sym);
-  Res.first->second.push_back(T);
+  ThunkVec->push_back(T);
   return std::make_pair(T, true);
 }
 
@@ -1316,7 +1333,7 @@ std::pair<Thunk *, bool> ThunkCreator::getThunk(Symbol &Sym, RelType Type,
 // InputSectionDescription::Sections.
 void ThunkCreator::forEachInputSectionDescription(
     ArrayRef<OutputSection *> OutputSections,
-    std::function<void(OutputSection *, InputSectionDescription *)> Fn) {
+    llvm::function_ref<void(OutputSection *, InputSectionDescription *)> Fn) {
   for (OutputSection *OS : OutputSections) {
     if (!(OS->Flags & SHF_ALLOC) || !(OS->Flags & SHF_EXECINSTR))
       continue;
@@ -1384,7 +1401,7 @@ bool ThunkCreator::createThunks(ArrayRef<OutputSection *> OutputSections) {
       OutputSections, [&](OutputSection *OS, InputSectionDescription *ISD) {
         for (InputSection *IS : ISD->Sections)
           for (Relocation &Rel : IS->Relocations) {
-            uint64_t Src = OS->Addr + IS->OutSecOff + Rel.Offset;
+            uint64_t Src = IS->getVA(Rel.Offset);
 
             // If we are a relocation to an existing Thunk, check if it is
             // still in range. If not then Rel will be altered to point to its
@@ -1399,7 +1416,6 @@ bool ThunkCreator::createThunks(ArrayRef<OutputSection *> OutputSections) {
             bool IsNew;
             std::tie(T, IsNew) = getThunk(*Rel.Sym, Rel.Type, Src);
             if (IsNew) {
-              AddressesChanged = true;
               // Find or create a ThunkSection for the new Thunk
               ThunkSection *TS;
               if (auto *TIS = T->getTargetInputSection())
@@ -1407,13 +1423,18 @@ bool ThunkCreator::createThunks(ArrayRef<OutputSection *> OutputSections) {
               else
                 TS = getISDThunkSec(OS, IS, ISD, Rel.Type, Src);
               TS->addThunk(T);
-              Thunks[T->ThunkSym] = T;
+              Thunks[T->getThunkTargetSym()] = T;
             }
             // Redirect relocation to Thunk, we never go via the PLT to a Thunk
-            Rel.Sym = T->ThunkSym;
+            Rel.Sym = T->getThunkTargetSym();
             Rel.Expr = fromPlt(Rel.Expr);
           }
+        for (auto &P : ISD->ThunkSections)
+          AddressesChanged |= P.first->assignOffsets();
       });
+  for (auto &P : ThunkedSections)
+    AddressesChanged |= P.second->assignOffsets();
+
   // Merge all created synthetic ThunkSections back into OutputSection
   mergeThunks(OutputSections);
   ++Pass;
diff --git a/gnu/llvm/tools/lld/ELF/SymbolTable.cpp b/gnu/llvm/tools/lld/ELF/SymbolTable.cpp
index c3a00bea4aa..1f5a84ec2c7 100644
--- a/gnu/llvm/tools/lld/ELF/SymbolTable.cpp
+++ b/gnu/llvm/tools/lld/ELF/SymbolTable.cpp
@@ -38,7 +38,7 @@ static InputFile *getFirstElf() {
     return ObjectFiles[0];
   if (!SharedFiles.empty())
     return SharedFiles[0];
-  return nullptr;
+  return BitcodeFiles[0];
 }
 
 // All input object files must be for the same architecture
@@ -82,6 +82,7 @@ template <class ELFT> void SymbolTable::addFile(InputFile *File) {
 
   // Lazy object file
   if (auto *F = dyn_cast<LazyObjFile>(File)) {
+    LazyObjFiles.push_back(F);
     F->parse<ELFT>();
     return;
   }
@@ -117,7 +118,7 @@ template <class ELFT> void SymbolTable::addFile(InputFile *File) {
 // not in native object file format but in the LLVM bitcode format.
 // This function compiles bitcode files into a few big native files
 // using LLVM functions and replaces bitcode symbols with the results.
-// Because all bitcode files that consist of a program are passed
+// Because all bitcode files that the program consists of are passed
 // to the compiler at once, it can do whole-program optimization.
 template <class ELFT> void SymbolTable::addCombinedLTOObject() {
   if (BitcodeFiles.empty())
@@ -130,7 +131,10 @@ template <class ELFT> void SymbolTable::addCombinedLTOObject() {
 
   for (InputFile *File : LTO->compile()) {
     DenseSet<CachedHashStringRef> DummyGroups;
-    cast<ObjFile<ELFT>>(File)->parse(DummyGroups);
+    auto *Obj = cast<ObjFile<ELFT>>(File);
+    Obj->parse(DummyGroups);
+    for (Symbol *Sym : Obj->getGlobalSymbols())
+      Sym->parseSymbolVersion();
     ObjectFiles.push_back(File);
   }
 }
@@ -154,6 +158,12 @@ template <class ELFT> void SymbolTable::addSymbolWrap(StringRef Name) {
   Symbol *Sym = find(Name);
   if (!Sym)
     return;
+
+  // Do not wrap the same symbol twice.
+  for (const WrappedSymbol &S : WrappedSymbols)
+    if (S.Sym == Sym)
+      return;
+
   Symbol *Real = addUndefined<ELFT>(Saver.save("__real_" + Name));
   Symbol *Wrap = addUndefined<ELFT>(Saver.save("__wrap_" + Name));
   WrappedSymbols.push_back({Sym, Real, Wrap});
@@ -186,7 +196,7 @@ void SymbolTable::applySymbolWrap() {
     // First, make a copy of __real_sym.
     Symbol *Real = nullptr;
     if (W.Real->isDefined()) {
-      Real = (Symbol *)make<SymbolUnion>();
+      Real = reinterpret_cast<Symbol *>(make<SymbolUnion>());
       memcpy(Real, W.Real, sizeof(SymbolUnion));
     }
 
@@ -234,8 +244,7 @@ std::pair<Symbol *, bool> SymbolTable::insert(StringRef Name) {
 
   Symbol *Sym;
   if (IsNew) {
-    Sym = (Symbol *)make<SymbolUnion>();
-    Sym->InVersionScript = false;
+    Sym = reinterpret_cast<Symbol *>(make<SymbolUnion>());
     Sym->Visibility = STV_DEFAULT;
     Sym->IsUsedInRegularObj = false;
     Sym->ExportDynamic = false;
@@ -294,26 +303,88 @@ Symbol *SymbolTable::addUndefined(StringRef Name, uint8_t Binding,
   uint8_t Visibility = getVisibility(StOther);
   std::tie(S, WasInserted) =
       insert(Name, Type, Visibility, CanOmitFromDynSym, File);
+
   // An undefined symbol with non default visibility must be satisfied
   // in the same DSO.
   if (WasInserted || (isa<SharedSymbol>(S) && Visibility != STV_DEFAULT)) {
     replaceSymbol<Undefined>(S, File, Name, Binding, StOther, Type);
     return S;
   }
+
   if (S->isShared() || S->isLazy() || (S->isUndefined() && Binding != STB_WEAK))
     S->Binding = Binding;
-  if (Binding != STB_WEAK) {
+
+  if (!Config->GcSections && Binding != STB_WEAK)
     if (auto *SS = dyn_cast<SharedSymbol>(S))
-      if (!Config->GcSections)
-        SS->getFile<ELFT>().IsNeeded = true;
-  }
-  if (auto *L = dyn_cast<Lazy>(S)) {
+      SS->getFile<ELFT>().IsNeeded = true;
+
+  if (S->isLazy()) {
     // An undefined weak will not fetch archive members. See comment on Lazy in
     // Symbols.h for the details.
-    if (Binding == STB_WEAK)
-      L->Type = Type;
-    else if (InputFile *F = L->fetch())
-      addFile<ELFT>(F);
+    if (Binding == STB_WEAK) {
+      S->Type = Type;
+      return S;
+    }
+
+    // Do extra check for --warn-backrefs.
+    //
+    // --warn-backrefs is an option to prevent an undefined reference from
+    // fetching an archive member written earlier in the command line. It can be
+    // used to keep compatibility with GNU linkers to some degree.
+    // I'll explain the feature and why you may find it useful in this comment.
+    //
+    // lld's symbol resolution semantics is more relaxed than traditional Unix
+    // linkers. For example,
+    //
+    //   ld.lld foo.a bar.o
+    //
+    // succeeds even if bar.o contains an undefined symbol that has to be
+    // resolved by some object file in foo.a. Traditional Unix linkers don't
+    // allow this kind of backward reference, as they visit each file only once
+    // from left to right in the command line while resolving all undefined
+    // symbols at the moment of visiting.
+    //
+    // In the above case, since there's no undefined symbol when a linker visits
+    // foo.a, no files are pulled out from foo.a, and because the linker forgets
+    // about foo.a after visiting, it can't resolve undefined symbols in bar.o
+    // that could have been resolved otherwise.
+    //
+    // That lld accepts more relaxed form means that (besides it'd make more
+    // sense) you can accidentally write a command line or a build file that
+    // works only with lld, even if you have a plan to distribute it to wider
+    // users who may be using GNU linkers. With --warn-backrefs, you can detect
+    // a library order that doesn't work with other Unix linkers.
+    //
+    // The option is also useful to detect cyclic dependencies between static
+    // archives. Again, lld accepts
+    //
+    //   ld.lld foo.a bar.a
+    //
+    // even if foo.a and bar.a depend on each other. With --warn-backrefs, it is
+    // handled as an error.
+    //
+    // Here is how the option works. We assign a group ID to each file. A file
+    // with a smaller group ID can pull out object files from an archive file
+    // with an equal or greater group ID. Otherwise, it is a reverse dependency
+    // and an error.
+    //
+    // A file outside --{start,end}-group gets a fresh ID when instantiated. All
+    // files within the same --{start,end}-group get the same group ID. E.g.
+    //
+    //   ld.lld A B --start-group C D --end-group E
+    //
+    // A forms group 0. B form group 1. C and D (including their member object
+    // files) form group 2. E forms group 3. I think that you can see how this
+    // group assignment rule simulates the traditional linker's semantics.
+    bool Backref =
+        Config->WarnBackrefs && File && S->File->GroupId < File->GroupId;
+    fetchLazy<ELFT>(S);
+
+    // We don't report backward references to weak symbols as they can be
+    // overridden later.
+    if (Backref && S->Binding != STB_WEAK)
+      warn("backward reference detected: " + Name + " in " + toString(File) +
+           " refers to " + toString(S->File));
   }
   return S;
 }
@@ -381,7 +452,11 @@ Symbol *SymbolTable::addCommon(StringRef N, uint64_t Size, uint32_t Alignment,
   bool WasInserted;
   std::tie(S, WasInserted) = insert(N, Type, getVisibility(StOther),
                                     /*CanOmitFromDynSym*/ false, &File);
+
   int Cmp = compareDefined(S, WasInserted, Binding, N);
+  if (Cmp < 0)
+    return S;
+
   if (Cmp > 0) {
     auto *Bss = make<BssSection>("COMMON", Size, Alignment);
     Bss->File = &File;
@@ -389,45 +464,43 @@ Symbol *SymbolTable::addCommon(StringRef N, uint64_t Size, uint32_t Alignment,
     InputSections.push_back(Bss);
 
     replaceSymbol<Defined>(S, &File, N, Binding, StOther, Type, 0, Size, Bss);
-  } else if (Cmp == 0) {
-    auto *D = cast<Defined>(S);
-    auto *Bss = dyn_cast_or_null<BssSection>(D->Section);
-    if (!Bss) {
-      // Non-common symbols take precedence over common symbols.
-      if (Config->WarnCommon)
-        warn("common " + S->getName() + " is overridden");
-      return S;
-    }
+    return S;
+  }
 
+  auto *D = cast<Defined>(S);
+  auto *Bss = dyn_cast_or_null<BssSection>(D->Section);
+  if (!Bss) {
+    // Non-common symbols take precedence over common symbols.
     if (Config->WarnCommon)
-      warn("multiple common of " + D->getName());
+      warn("common " + S->getName() + " is overridden");
+    return S;
+  }
 
-    Bss->Alignment = std::max(Bss->Alignment, Alignment);
-    if (Size > Bss->Size) {
-      D->File = Bss->File = &File;
-      D->Size = Bss->Size = Size;
-    }
+  if (Config->WarnCommon)
+    warn("multiple common of " + D->getName());
+
+  Bss->Alignment = std::max(Bss->Alignment, Alignment);
+  if (Size > Bss->Size) {
+    D->File = Bss->File = &File;
+    D->Size = Bss->Size = Size;
   }
   return S;
 }
 
-static void warnOrError(const Twine &Msg) {
-  if (Config->AllowMultipleDefinition)
-    warn(Msg);
-  else
-    error(Msg);
-}
-
 static void reportDuplicate(Symbol *Sym, InputFile *NewFile) {
-  warnOrError("duplicate symbol: " + toString(*Sym) + "\n>>> defined in " +
-              toString(Sym->File) + "\n>>> defined in " + toString(NewFile));
+  if (!Config->AllowMultipleDefinition)
+    error("duplicate symbol: " + toString(*Sym) + "\n>>> defined in " +
+          toString(Sym->File) + "\n>>> defined in " + toString(NewFile));
 }
 
-static void reportDuplicate(Symbol *Sym, InputSectionBase *ErrSec,
-                            uint64_t ErrOffset) {
+static void reportDuplicate(Symbol *Sym, InputFile *NewFile,
+                            InputSectionBase *ErrSec, uint64_t ErrOffset) {
+  if (Config->AllowMultipleDefinition)
+    return;
+
   Defined *D = cast<Defined>(Sym);
   if (!D->Section || !ErrSec) {
-    reportDuplicate(Sym, ErrSec ? ErrSec->File : nullptr);
+    reportDuplicate(Sym, NewFile);
     return;
   }
 
@@ -451,7 +524,7 @@ static void reportDuplicate(Symbol *Sym, InputSectionBase *ErrSec,
   if (!Src2.empty())
     Msg += Src2 + "\n>>>            ";
   Msg += Obj2;
-  warnOrError(Msg);
+  error(Msg);
 }
 
 Symbol *SymbolTable::addRegular(StringRef Name, uint8_t StOther, uint8_t Type,
@@ -467,7 +540,8 @@ Symbol *SymbolTable::addRegular(StringRef Name, uint8_t StOther, uint8_t Type,
     replaceSymbol<Defined>(S, File, Name, Binding, StOther, Type, Value, Size,
                            Section);
   else if (Cmp == 0)
-    reportDuplicate(S, dyn_cast_or_null<InputSectionBase>(Section), Value);
+    reportDuplicate(S, File, dyn_cast_or_null<InputSectionBase>(Section),
+                    Value);
   return S;
 }
 
@@ -488,8 +562,8 @@ void SymbolTable::addShared(StringRef Name, SharedFile<ELFT> &File,
 
   // An undefined symbol with non default visibility must be satisfied
   // in the same DSO.
-  if (WasInserted || ((S->isUndefined() || S->isLazy()) &&
-                      S->getVisibility() == STV_DEFAULT)) {
+  if (WasInserted ||
+      ((S->isUndefined() || S->isLazy()) && S->Visibility == STV_DEFAULT)) {
     uint8_t Binding = S->Binding;
     bool WasUndefined = S->isUndefined();
     replaceSymbol<SharedSymbol>(S, File, Name, Sym.getBinding(), Sym.st_other,
@@ -528,85 +602,58 @@ Symbol *SymbolTable::find(StringRef Name) {
   return SymVector[It->second];
 }
 
-template <class ELFT>
-Symbol *SymbolTable::addLazyArchive(StringRef Name, ArchiveFile &F,
-                                    const object::Archive::Symbol Sym) {
+// This is used to handle lazy symbols. May replace existent
+// symbol with lazy version or request to Fetch it.
+template <class ELFT, typename LazyT, typename... ArgT>
+static void replaceOrFetchLazy(StringRef Name, InputFile &File,
+                               llvm::function_ref<InputFile *()> Fetch,
+                               ArgT &&... Arg) {
   Symbol *S;
   bool WasInserted;
-  std::tie(S, WasInserted) = insert(Name);
+  std::tie(S, WasInserted) = Symtab->insert(Name);
   if (WasInserted) {
-    replaceSymbol<LazyArchive>(S, F, Sym, Symbol::UnknownType);
-    return S;
+    replaceSymbol<LazyT>(S, File, Symbol::UnknownType,
+                         std::forward<ArgT>(Arg)...);
+    return;
   }
   if (!S->isUndefined())
-    return S;
+    return;
 
   // An undefined weak will not fetch archive members. See comment on Lazy in
   // Symbols.h for the details.
   if (S->isWeak()) {
-    replaceSymbol<LazyArchive>(S, F, Sym, S->Type);
+    replaceSymbol<LazyT>(S, File, S->Type, std::forward<ArgT>(Arg)...);
     S->Binding = STB_WEAK;
-    return S;
+    return;
   }
-  std::pair<MemoryBufferRef, uint64_t> MBInfo = F.getMember(&Sym);
-  if (!MBInfo.first.getBuffer().empty())
-    addFile<ELFT>(createObjectFile(MBInfo.first, F.getName(), MBInfo.second));
-  return S;
+
+  if (InputFile *F = Fetch())
+    Symtab->addFile<ELFT>(F);
 }
 
 template <class ELFT>
-void SymbolTable::addLazyObject(StringRef Name, LazyObjFile &Obj) {
-  Symbol *S;
-  bool WasInserted;
-  std::tie(S, WasInserted) = insert(Name);
-  if (WasInserted) {
-    replaceSymbol<LazyObject>(S, Obj, Name, Symbol::UnknownType);
-    return;
-  }
-  if (!S->isUndefined())
-    return;
-
-  // See comment for addLazyArchive above.
-  if (S->isWeak())
-    replaceSymbol<LazyObject>(S, Obj, Name, S->Type);
-  else if (InputFile *F = Obj.fetch())
-    addFile<ELFT>(F);
-}
-
-// If we already saw this symbol, force loading its file.
-template <class ELFT> void SymbolTable::fetchIfLazy(StringRef Name) {
-  if (Symbol *B = find(Name)) {
-    // Mark the symbol not to be eliminated by LTO
-    // even if it is a bitcode symbol.
-    B->IsUsedInRegularObj = true;
-    if (auto *L = dyn_cast<Lazy>(B))
-      if (InputFile *File = L->fetch())
-        addFile<ELFT>(File);
-  }
+void SymbolTable::addLazyArchive(StringRef Name, ArchiveFile &F,
+                                 const object::Archive::Symbol Sym) {
+  replaceOrFetchLazy<ELFT, LazyArchive>(Name, F, [&]() { return F.fetch(Sym); },
+                                        Sym);
 }
 
-// This function takes care of the case in which shared libraries depend on
-// the user program (not the other way, which is usual). Shared libraries
-// may have undefined symbols, expecting that the user program provides
-// the definitions for them. An example is BSD's __progname symbol.
-// We need to put such symbols to the main program's .dynsym so that
-// shared libraries can find them.
-// Except this, we ignore undefined symbols in DSOs.
-template <class ELFT> void SymbolTable::scanShlibUndefined() {
-  for (InputFile *F : SharedFiles) {
-    for (StringRef U : cast<SharedFile<ELFT>>(F)->getUndefinedSymbols()) {
-      Symbol *Sym = find(U);
-      if (!Sym || !Sym->isDefined())
-        continue;
-      Sym->ExportDynamic = true;
+template <class ELFT>
+void SymbolTable::addLazyObject(StringRef Name, LazyObjFile &Obj) {
+  replaceOrFetchLazy<ELFT, LazyObject>(Name, Obj, [&]() { return Obj.fetch(); },
+                                       Name);
+}
 
-      // If -dynamic-list is given, the default version is set to
-      // VER_NDX_LOCAL, which prevents a symbol to be exported via .dynsym.
-      // Set to VER_NDX_GLOBAL so the symbol will be handled as if it were
-      // specified by -dynamic-list.
-      Sym->VersionId = VER_NDX_GLOBAL;
-    }
+template <class ELFT> void SymbolTable::fetchLazy(Symbol *Sym) {
+  if (auto *S = dyn_cast<LazyArchive>(Sym)) {
+    if (InputFile *File = S->fetch())
+      addFile<ELFT>(File);
+    return;
   }
+
+  auto *S = cast<LazyObject>(Sym);
+  if (InputFile *File = cast<LazyObjFile>(S->File)->fetch())
+    addFile<ELFT>(File);
 }
 
 // Initialize DemangledSyms with a map from demangled symbols to symbol
@@ -705,7 +752,7 @@ void SymbolTable::assignExactVersion(SymbolVersion Ver, uint16_t VersionId,
   // Get a list of symbols which we need to assign the version to.
   std::vector<Symbol *> Syms = findByVersion(Ver);
   if (Syms.empty()) {
-    if (Config->NoUndefinedVersion)
+    if (!Config->UndefinedVersion)
       error("version script assignment of '" + VersionName + "' to symbol '" +
             Ver.Name + "' failed: symbol not defined");
     return;
@@ -719,10 +766,10 @@ void SymbolTable::assignExactVersion(SymbolVersion Ver, uint16_t VersionId,
     if (Sym->getName().contains('@'))
       continue;
 
-    if (Sym->InVersionScript)
-      warn("duplicate symbol '" + Ver.Name + "' in version script");
+    if (Sym->VersionId != Config->DefaultSymbolVersion &&
+        Sym->VersionId != VersionId)
+      error("duplicate symbol '" + Ver.Name + "' in version script");
     Sym->VersionId = VersionId;
-    Sym->InVersionScript = true;
   }
 }
 
@@ -770,6 +817,11 @@ void SymbolTable::scanVersionScript() {
     Sym->parseSymbolVersion();
 }
 
+template void SymbolTable::addFile<ELF32LE>(InputFile *);
+template void SymbolTable::addFile<ELF32BE>(InputFile *);
+template void SymbolTable::addFile<ELF64LE>(InputFile *);
+template void SymbolTable::addFile<ELF64BE>(InputFile *);
+
 template void SymbolTable::addSymbolWrap<ELF32LE>(StringRef);
 template void SymbolTable::addSymbolWrap<ELF32BE>(StringRef);
 template void SymbolTable::addSymbolWrap<ELF64LE>(StringRef);
@@ -794,16 +846,16 @@ template void SymbolTable::addCombinedLTOObject<ELF32BE>();
 template void SymbolTable::addCombinedLTOObject<ELF64LE>();
 template void SymbolTable::addCombinedLTOObject<ELF64BE>();
 
-template Symbol *
+template void
 SymbolTable::addLazyArchive<ELF32LE>(StringRef, ArchiveFile &,
                                      const object::Archive::Symbol);
-template Symbol *
+template void
 SymbolTable::addLazyArchive<ELF32BE>(StringRef, ArchiveFile &,
                                      const object::Archive::Symbol);
-template Symbol *
+template void
 SymbolTable::addLazyArchive<ELF64LE>(StringRef, ArchiveFile &,
                                      const object::Archive::Symbol);
-template Symbol *
+template void
 SymbolTable::addLazyArchive<ELF64BE>(StringRef, ArchiveFile &,
                                      const object::Archive::Symbol);
 
@@ -812,6 +864,11 @@ template void SymbolTable::addLazyObject<ELF32BE>(StringRef, LazyObjFile &);
 template void SymbolTable::addLazyObject<ELF64LE>(StringRef, LazyObjFile &);
 template void SymbolTable::addLazyObject<ELF64BE>(StringRef, LazyObjFile &);
 
+template void SymbolTable::fetchLazy<ELF32LE>(Symbol *);
+template void SymbolTable::fetchLazy<ELF32BE>(Symbol *);
+template void SymbolTable::fetchLazy<ELF64LE>(Symbol *);
+template void SymbolTable::fetchLazy<ELF64BE>(Symbol *);
+
 template void SymbolTable::addShared<ELF32LE>(StringRef, SharedFile<ELF32LE> &,
                                               const typename ELF32LE::Sym &,
                                               uint32_t Alignment, uint32_t);
@@ -824,13 +881,3 @@ template void SymbolTable::addShared<ELF64LE>(StringRef, SharedFile<ELF64LE> &,
 template void SymbolTable::addShared<ELF64BE>(StringRef, SharedFile<ELF64BE> &,
                                               const typename ELF64BE::Sym &,
                                               uint32_t Alignment, uint32_t);
-
-template void SymbolTable::fetchIfLazy<ELF32LE>(StringRef);
-template void SymbolTable::fetchIfLazy<ELF32BE>(StringRef);
-template void SymbolTable::fetchIfLazy<ELF64LE>(StringRef);
-template void SymbolTable::fetchIfLazy<ELF64BE>(StringRef);
-
-template void SymbolTable::scanShlibUndefined<ELF32LE>();
-template void SymbolTable::scanShlibUndefined<ELF32BE>();
-template void SymbolTable::scanShlibUndefined<ELF64LE>();
-template void SymbolTable::scanShlibUndefined<ELF64BE>();
diff --git a/gnu/llvm/tools/lld/ELF/Symbols.cpp b/gnu/llvm/tools/lld/ELF/Symbols.cpp
index 6e0a83c9612..dc0d891af97 100644
--- a/gnu/llvm/tools/lld/ELF/Symbols.cpp
+++ b/gnu/llvm/tools/lld/ELF/Symbols.cpp
@@ -14,7 +14,6 @@
 #include "SyntheticSections.h"
 #include "Target.h"
 #include "Writer.h"
-
 #include "lld/Common/ErrorHandler.h"
 #include "lld/Common/Strings.h"
 #include "llvm/ADT/STLExtras.h"
@@ -40,6 +39,7 @@ Defined *ElfSym::GlobalOffsetTable;
 Defined *ElfSym::MipsGp;
 Defined *ElfSym::MipsGpDisp;
 Defined *ElfSym::MipsLocalGp;
+Defined *ElfSym::RelaIpltEnd;
 
 static uint64_t getSymVA(const Symbol &Sym, int64_t &Addend) {
   switch (Sym.kind()) {
@@ -59,6 +59,7 @@ static uint64_t getSymVA(const Symbol &Sym, int64_t &Addend) {
       return D.Value;
 
     IS = IS->Repl;
+
     uint64_t Offset = D.Value;
 
     // An object in an SHF_MERGE section might be referenced via a
@@ -77,8 +78,6 @@ static uint64_t getSymVA(const Symbol &Sym, int64_t &Addend) {
       Addend = 0;
     }
 
-    const OutputSection *OutSec = IS->getOutputSection();
-
     // In the typical case, this is actually very simple and boils
     // down to adding together 3 numbers:
     // 1. The address of the output section.
@@ -89,7 +88,7 @@ static uint64_t getSymVA(const Symbol &Sym, int64_t &Addend) {
     // If you understand the data structures involved with this next
     // line (and how they get built), then you have a pretty good
     // understanding of the linker.
-    uint64_t VA = (OutSec ? OutSec->Addr : 0) + IS->getOffset(Offset);
+    uint64_t VA = IS->getVA(Offset);
 
     if (D.isTls() && !Config->Relocatable) {
       if (!Out::TlsPhdr)
@@ -99,20 +98,12 @@ static uint64_t getSymVA(const Symbol &Sym, int64_t &Addend) {
     }
     return VA;
   }
-  case Symbol::SharedKind: {
-    auto &SS = cast<SharedSymbol>(Sym);
-    if (SS.CopyRelSec)
-      return SS.CopyRelSec->getParent()->Addr + SS.CopyRelSec->OutSecOff;
-    if (SS.NeedsPltAddr)
-      return Sym.getPltVA();
-    return 0;
-  }
+  case Symbol::SharedKind:
   case Symbol::UndefinedKind:
     return 0;
   case Symbol::LazyArchiveKind:
   case Symbol::LazyObjectKind:
-    assert(Sym.IsUsedInRegularObj && "lazy symbol reached writer");
-    return 0;
+    llvm_unreachable("lazy symbol reached writer");
   }
   llvm_unreachable("invalid symbol kind");
 }
@@ -135,22 +126,26 @@ uint64_t Symbol::getGotPltVA() const {
 }
 
 uint64_t Symbol::getGotPltOffset() const {
-  return GotPltIndex * Target->GotPltEntrySize;
+  if (IsInIgot)
+    return PltIndex * Target->GotPltEntrySize;
+  return (PltIndex + Target->GotPltHeaderEntriesNum) * Target->GotPltEntrySize;
 }
 
 uint64_t Symbol::getPltVA() const {
   if (this->IsInIplt)
     return InX::Iplt->getVA() + PltIndex * Target->PltEntrySize;
-  return InX::Plt->getVA() + Target->PltHeaderSize +
-         PltIndex * Target->PltEntrySize;
+  return InX::Plt->getVA() + Target->getPltEntryOffset(PltIndex);
+}
+
+uint64_t Symbol::getPltOffset() const {
+  assert(!this->IsInIplt);
+  return Target->getPltEntryOffset(PltIndex);
 }
 
 uint64_t Symbol::getSize() const {
   if (const auto *DR = dyn_cast<Defined>(this))
     return DR->Size;
-  if (const auto *S = dyn_cast<SharedSymbol>(this))
-    return S->Size;
-  return 0;
+  return cast<SharedSymbol>(this)->Size;
 }
 
 OutputSection *Symbol::getOutputSection() const {
@@ -159,13 +154,6 @@ OutputSection *Symbol::getOutputSection() const {
       return Sec->Repl->getOutputSection();
     return nullptr;
   }
-
-  if (auto *S = dyn_cast<SharedSymbol>(this)) {
-    if (S->CopyRelSec)
-      return S->CopyRelSec->getParent();
-    return nullptr;
-  }
-
   return nullptr;
 }
 
@@ -181,7 +169,7 @@ void Symbol::parseSymbolVersion() {
     return;
 
   // Truncate the symbol name so that it doesn't include the version string.
-  Name = {S.data(), Pos};
+  NameSize = Pos;
 
   // If this is not in this DSO, it is not a definition.
   if (!isDefined())
@@ -207,42 +195,24 @@ void Symbol::parseSymbolVersion() {
   // It is an error if the specified version is not defined.
   // Usually version script is not provided when linking executable,
   // but we may still want to override a versioned symbol from DSO,
-  // so we do not report error in this case.
-  if (Config->Shared)
+  // so we do not report error in this case. We also do not error
+  // if the symbol has a local version as it won't be in the dynamic
+  // symbol table.
+  if (Config->Shared && VersionId != VER_NDX_LOCAL)
     error(toString(File) + ": symbol " + S + " has undefined version " +
           Verstr);
 }
 
-InputFile *Lazy::fetch() {
-  if (auto *S = dyn_cast<LazyArchive>(this))
-    return S->fetch();
-  return cast<LazyObject>(this)->fetch();
-}
-
-ArchiveFile &LazyArchive::getFile() { return *cast<ArchiveFile>(File); }
-
-InputFile *LazyArchive::fetch() {
-  std::pair<MemoryBufferRef, uint64_t> MBInfo = getFile().getMember(&Sym);
-
-  // getMember returns an empty buffer if the member was already
-  // read from the library.
-  if (MBInfo.first.getBuffer().empty())
-    return nullptr;
-  return createObjectFile(MBInfo.first, getFile().getName(), MBInfo.second);
-}
-
-LazyObjFile &LazyObject::getFile() { return *cast<LazyObjFile>(File); }
-
-InputFile *LazyObject::fetch() { return getFile().fetch(); }
+InputFile *LazyArchive::fetch() { return cast<ArchiveFile>(File)->fetch(Sym); }
 
 uint8_t Symbol::computeBinding() const {
   if (Config->Relocatable)
     return Binding;
   if (Visibility != STV_DEFAULT && Visibility != STV_PROTECTED)
     return STB_LOCAL;
-  if (VersionId == VER_NDX_LOCAL && isDefined())
+  if (VersionId == VER_NDX_LOCAL && isDefined() && !IsPreemptible)
     return STB_LOCAL;
-  if (Config->NoGnuUnique && Binding == STB_GNU_UNIQUE)
+  if (!Config->GnuUnique && Binding == STB_GNU_UNIQUE)
     return STB_GLOBAL;
   return Binding;
 }
@@ -274,6 +244,27 @@ void elf::printTraceSymbol(Symbol *Sym) {
   message(toString(Sym->File) + S + Sym->getName());
 }
 
+void elf::warnUnorderableSymbol(const Symbol *Sym) {
+  if (!Config->WarnSymbolOrdering)
+    return;
+
+  const InputFile *File = Sym->File;
+  auto *D = dyn_cast<Defined>(Sym);
+
+  auto Warn = [&](StringRef S) { warn(toString(File) + S + Sym->getName()); };
+
+  if (Sym->isUndefined())
+    Warn(": unable to order undefined symbol: ");
+  else if (Sym->isShared())
+    Warn(": unable to order shared symbol: ");
+  else if (D && !D->Section)
+    Warn(": unable to order absolute symbol: ");
+  else if (D && isa<OutputSection>(D->Section))
+    Warn(": unable to order synthetic symbol: ");
+  else if (D && !D->Section->Repl->Live)
+    Warn(": unable to order discarded symbol: ");
+}
+
 // Returns a symbol for an error message.
 std::string lld::toString(const Symbol &B) {
   if (Config->Demangle)
diff --git a/gnu/llvm/tools/lld/ELF/Symbols.h b/gnu/llvm/tools/lld/ELF/Symbols.h
index 1e3c0af64ef..6a33f5ebce2 100644
--- a/gnu/llvm/tools/lld/ELF/Symbols.h
+++ b/gnu/llvm/tools/lld/ELF/Symbols.h
@@ -7,8 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// All symbols are handled as SymbolBodies regardless of their types.
-// This file defines various types of SymbolBodies.
+// This file defines various types of Symbols.
 //
 //===----------------------------------------------------------------------===//
 
@@ -16,9 +15,8 @@
 #define LLD_ELF_SYMBOLS_H
 
 #include "InputSection.h"
-#include "Strings.h"
-
 #include "lld/Common/LLVM.h"
+#include "lld/Common/Strings.h"
 #include "llvm/Object/Archive.h"
 #include "llvm/Object/ELF.h"
 
@@ -34,6 +32,20 @@ template <class ELFT> class ObjFile;
 class OutputSection;
 template <class ELFT> class SharedFile;
 
+// This is a StringRef-like container that doesn't run strlen().
+//
+// ELF string tables contain a lot of null-terminated strings. Most of them
+// are not necessary for the linker because they are names of local symbols,
+// and the linker doesn't use local symbol names for name resolution. So, we
+// use this class to represents strings read from string tables.
+struct StringRefZ {
+  StringRefZ(const char *S) : Data(S), Size(-1) {}
+  StringRefZ(StringRef S) : Data(S.data()), Size(S.size()) {}
+
+  const char *Data;
+  const uint32_t Size;
+};
+
 // The base class for real symbol classes.
 class Symbol {
 public:
@@ -47,6 +59,25 @@ public:
 
   Kind kind() const { return static_cast<Kind>(SymbolKind); }
 
+  // The file from which this symbol was created.
+  InputFile *File;
+
+protected:
+  const char *NameData;
+  mutable uint32_t NameSize;
+
+public:
+  uint32_t DynsymIndex = 0;
+  uint32_t GotIndex = -1;
+  uint32_t PltIndex = -1;
+  uint32_t GlobalDynIndex = -1;
+
+  // This field is a index to the symbol's version definition.
+  uint32_t VerdefIndex = -1;
+
+  // Version definition index.
+  uint16_t VersionId;
+
   // Symbol binding. This is not overwritten by replaceSymbol to track
   // changes during resolution. In particular:
   //  - An undefined weak is still weak when it resolves to a shared library.
@@ -54,8 +85,11 @@ public:
   //    remember it is weak.
   uint8_t Binding;
 
-  // Version definition index.
-  uint16_t VersionId;
+  // The following fields have the same meaning as the ELF symbol attributes.
+  uint8_t Type;    // symbol type
+  uint8_t StOther; // st_other field value
+
+  const uint8_t SymbolKind;
 
   // Symbol visibility. This is the computed minimum visibility of all
   // observed non-DSO symbols.
@@ -81,12 +115,6 @@ public:
   // True if this symbol is specified by --trace-symbol option.
   unsigned Traced : 1;
 
-  // This symbol version was found in a version script.
-  unsigned InVersionScript : 1;
-
-  // The file from which this symbol was created.
-  InputFile *File;
-
   bool includeInDynsym() const;
   uint8_t computeBinding() const;
   bool isWeak() const { return Binding == llvm::ELF::STB_WEAK; }
@@ -100,15 +128,15 @@ public:
     return SymbolKind == LazyArchiveKind || SymbolKind == LazyObjectKind;
   }
 
-  // True is this is an undefined weak symbol. This only works once
-  // all input files have been added.
-  bool isUndefWeak() const {
-    // See comment on Lazy the details.
-    return isWeak() && (isUndefined() || isLazy());
+  // True if this is an undefined weak symbol.
+  bool isUndefWeak() const { return isWeak() && isUndefined(); }
+
+  StringRef getName() const {
+    if (NameSize == (uint32_t)-1)
+      NameSize = strlen(NameData);
+    return {NameData, NameSize};
   }
 
-  StringRef getName() const { return Name; }
-  uint8_t getVisibility() const { return StOther & 0x3; }
   void parseSymbolVersion();
 
   bool isInGot() const { return GotIndex != -1U; }
@@ -121,34 +149,22 @@ public:
   uint64_t getGotPltOffset() const;
   uint64_t getGotPltVA() const;
   uint64_t getPltVA() const;
+  uint64_t getPltOffset() const;
   uint64_t getSize() const;
   OutputSection *getOutputSection() const;
 
-  uint32_t DynsymIndex = 0;
-  uint32_t GotIndex = -1;
-  uint32_t GotPltIndex = -1;
-  uint32_t PltIndex = -1;
-  uint32_t GlobalDynIndex = -1;
-
 protected:
   Symbol(Kind K, InputFile *File, StringRefZ Name, uint8_t Binding,
          uint8_t StOther, uint8_t Type)
-      : Binding(Binding), File(File), SymbolKind(K), NeedsPltAddr(false),
-        IsInGlobalMipsGot(false), Is32BitMipsGot(false), IsInIplt(false),
-        IsInIgot(false), IsPreemptible(false), Used(!Config->GcSections),
-        Type(Type), StOther(StOther), Name(Name) {}
-
-  const unsigned SymbolKind : 8;
+      : File(File), NameData(Name.Data), NameSize(Name.Size), Binding(Binding),
+        Type(Type), StOther(StOther), SymbolKind(K), NeedsPltAddr(false),
+        IsInIplt(false), IsInIgot(false), IsPreemptible(false),
+        Used(!Config->GcSections), NeedsTocRestore(false) {}
 
 public:
   // True the symbol should point to its PLT entry.
   // For SharedSymbol only.
   unsigned NeedsPltAddr : 1;
-  // True if this symbol has an entry in the global part of MIPS GOT.
-  unsigned IsInGlobalMipsGot : 1;
-
-  // True if this symbol is referenced by 32-bit GOT relocations.
-  unsigned Is32BitMipsGot : 1;
 
   // True if this symbol is in the Iplt sub-section of the Plt.
   unsigned IsInIplt : 1;
@@ -156,14 +172,15 @@ public:
   // True if this symbol is in the Igot sub-section of the .got.plt or .got.
   unsigned IsInIgot : 1;
 
+  // True if this symbol is preemptible at load time.
   unsigned IsPreemptible : 1;
 
   // True if an undefined or shared symbol is used from a live section.
   unsigned Used : 1;
 
-  // The following fields have the same meaning as the ELF symbol attributes.
-  uint8_t Type;    // symbol type
-  uint8_t StOther; // st_other field value
+  // True if a call to this symbol needs to be followed by a restore of the
+  // PPC64 toc pointer.
+  unsigned NeedsTocRestore : 1;
 
   // The Type field may also have this value. It means that we have not yet seen
   // a non-Lazy symbol with this name, so we don't know what its type is. The
@@ -178,9 +195,6 @@ public:
   bool isGnuIFunc() const { return Type == llvm::ELF::STT_GNU_IFUNC; }
   bool isObject() const { return Type == llvm::ELF::STT_OBJECT; }
   bool isFile() const { return Type == llvm::ELF::STT_FILE; }
-
-protected:
-  StringRefZ Name;
 };
 
 // Represents a symbol that is defined in the current output file.
@@ -214,8 +228,9 @@ public:
   SharedSymbol(InputFile &File, StringRef Name, uint8_t Binding,
                uint8_t StOther, uint8_t Type, uint64_t Value, uint64_t Size,
                uint32_t Alignment, uint32_t VerdefIndex)
-      : Symbol(SharedKind, &File, Name, Binding, StOther, Type), Value(Value),
-        Size(Size), VerdefIndex(VerdefIndex), Alignment(Alignment) {
+      : Symbol(SharedKind, &File, Name, Binding, StOther, Type),
+        Alignment(Alignment), Value(Value), Size(Size) {
+    this->VerdefIndex = VerdefIndex;
     // GNU ifunc is a mechanism to allow user-supplied functions to
     // resolve PLT slot values at load-time. This is contrary to the
     // regular symbol resolution scheme in which symbols are resolved just
@@ -240,54 +255,36 @@ public:
     return *cast<SharedFile<ELFT>>(File);
   }
 
-  // If not null, there is a copy relocation to this section.
-  InputSection *CopyRelSec = nullptr;
+  uint32_t Alignment;
 
   uint64_t Value; // st_value
   uint64_t Size;  // st_size
-
-  // This field is a index to the symbol's version definition.
-  uint32_t VerdefIndex;
-
-  uint32_t Alignment;
 };
 
-// This represents a symbol that is not yet in the link, but we know where to
-// find it if needed. If the resolver finds both Undefined and Lazy for the same
-// name, it will ask the Lazy to load a file.
+// LazyArchive and LazyObject represent a symbols that is not yet in the link,
+// but we know where to find it if needed. If the resolver finds both Undefined
+// and Lazy for the same name, it will ask the Lazy to load a file.
 //
 // A special complication is the handling of weak undefined symbols. They should
 // not load a file, but we have to remember we have seen both the weak undefined
 // and the lazy. We represent that with a lazy symbol with a weak binding. This
 // means that code looking for undefined symbols normally also has to take lazy
 // symbols into consideration.
-class Lazy : public Symbol {
-public:
-  static bool classof(const Symbol *S) { return S->isLazy(); }
-
-  // Returns an object file for this symbol, or a nullptr if the file
-  // was already returned.
-  InputFile *fetch();
-
-protected:
-  Lazy(Kind K, InputFile &File, StringRef Name, uint8_t Type)
-      : Symbol(K, &File, Name, llvm::ELF::STB_GLOBAL, llvm::ELF::STV_DEFAULT,
-               Type) {}
-};
 
 // This class represents a symbol defined in an archive file. It is
 // created from an archive file header, and it knows how to load an
 // object file from an archive to replace itself with a defined
 // symbol.
-class LazyArchive : public Lazy {
+class LazyArchive : public Symbol {
 public:
-  LazyArchive(InputFile &File, const llvm::object::Archive::Symbol S,
-              uint8_t Type)
-      : Lazy(LazyArchiveKind, File, S.getName(), Type), Sym(S) {}
+  LazyArchive(InputFile &File, uint8_t Type,
+              const llvm::object::Archive::Symbol S)
+      : Symbol(LazyArchiveKind, &File, S.getName(), llvm::ELF::STB_GLOBAL,
+               llvm::ELF::STV_DEFAULT, Type),
+        Sym(S) {}
 
   static bool classof(const Symbol *S) { return S->kind() == LazyArchiveKind; }
 
-  ArchiveFile &getFile();
   InputFile *fetch();
 
 private:
@@ -296,15 +293,13 @@ private:
 
 // LazyObject symbols represents symbols in object files between
 // --start-lib and --end-lib options.
-class LazyObject : public Lazy {
+class LazyObject : public Symbol {
 public:
-  LazyObject(InputFile &File, StringRef Name, uint8_t Type)
-      : Lazy(LazyObjectKind, File, Name, Type) {}
+  LazyObject(InputFile &File, uint8_t Type, StringRef Name)
+      : Symbol(LazyObjectKind, &File, Name, llvm::ELF::STB_GLOBAL,
+               llvm::ELF::STV_DEFAULT, Type) {}
 
   static bool classof(const Symbol *S) { return S->kind() == LazyObjectKind; }
-
-  LazyObjFile &getFile();
-  InputFile *fetch();
 };
 
 // Some linker-generated symbols need to be created as
@@ -337,6 +332,9 @@ struct ElfSym {
   static Defined *MipsGp;
   static Defined *MipsGpDisp;
   static Defined *MipsLocalGp;
+
+  // __rela_iplt_end or __rel_iplt_end
+  static Defined *RelaIpltEnd;
 };
 
 // A buffer class that is large enough to hold any Symbol-derived
@@ -354,6 +352,8 @@ void printTraceSymbol(Symbol *Sym);
 
 template <typename T, typename... ArgT>
 void replaceSymbol(Symbol *S, ArgT &&... Arg) {
+  static_assert(std::is_trivially_destructible<T>(),
+                "Symbol types must be trivially destructible");
   static_assert(sizeof(T) <= sizeof(SymbolUnion), "SymbolUnion too small");
   static_assert(alignof(T) <= alignof(SymbolUnion),
                 "SymbolUnion not aligned enough");
@@ -370,13 +370,14 @@ void replaceSymbol(Symbol *S, ArgT &&... Arg) {
   S->ExportDynamic = Sym.ExportDynamic;
   S->CanInline = Sym.CanInline;
   S->Traced = Sym.Traced;
-  S->InVersionScript = Sym.InVersionScript;
 
   // Print out a log message if --trace-symbol was specified.
   // This is for debugging.
   if (S->Traced)
     printTraceSymbol(S);
 }
+
+void warnUnorderableSymbol(const Symbol *Sym);
 } // namespace elf
 
 std::string toString(const elf::Symbol &B);
diff --git a/gnu/llvm/tools/lld/ELF/SyntheticSections.cpp b/gnu/llvm/tools/lld/ELF/SyntheticSections.cpp
index 023554cb268..475531f0ad1 100644
--- a/gnu/llvm/tools/lld/ELF/SyntheticSections.cpp
+++ b/gnu/llvm/tools/lld/ELF/SyntheticSections.cpp
@@ -20,15 +20,16 @@
 #include "InputFiles.h"
 #include "LinkerScript.h"
 #include "OutputSections.h"
-#include "Strings.h"
 #include "SymbolTable.h"
 #include "Symbols.h"
 #include "Target.h"
 #include "Writer.h"
 #include "lld/Common/ErrorHandler.h"
 #include "lld/Common/Memory.h"
+#include "lld/Common/Strings.h"
 #include "lld/Common/Threads.h"
 #include "lld/Common/Version.h"
+#include "llvm/ADT/SetOperations.h"
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugPubTable.h"
 #include "llvm/Object/Decompressor.h"
@@ -47,27 +48,20 @@ using namespace llvm::dwarf;
 using namespace llvm::ELF;
 using namespace llvm::object;
 using namespace llvm::support;
-using namespace llvm::support::endian;
 
 using namespace lld;
 using namespace lld::elf;
 
-constexpr size_t MergeNoTailSection::NumShards;
-
-static void write32(void *Buf, uint32_t Val) {
-  endian::write32(Buf, Val, Config->Endianness);
-}
+using llvm::support::endian::read32le;
+using llvm::support::endian::write32le;
+using llvm::support::endian::write64le;
 
-uint64_t SyntheticSection::getVA() const {
-  if (OutputSection *Sec = getParent())
-    return Sec->Addr + OutSecOff;
-  return 0;
-}
+constexpr size_t MergeNoTailSection::NumShards;
 
 // Returns an LLD version string.
 static ArrayRef<uint8_t> getVersion() {
   // Check LLD_VERSION first for ease of testing.
-  // You can get consitent output by using the environment variable.
+  // You can get consistent output by using the environment variable.
   // This is only for testing.
   StringRef S = getenv("LLD_VERSION");
   if (S.empty())
@@ -192,8 +186,6 @@ MipsOptionsSection<ELFT> *MipsOptionsSection<ELFT>::create() {
 
       auto *Opt = reinterpret_cast<const Elf_Mips_Options *>(D.data());
       if (Opt->kind == ODK_REGINFO) {
-        if (Config->Relocatable && Opt->getRegInfo().ri_gp_value)
-          error(Filename + ": unsupported non-zero ri_gp_value");
         Reginfo.ri_gprmask |= Opt->getRegInfo().ri_gprmask;
         Sec->getFile<ELFT>()->MipsGp0 = Opt->getRegInfo().ri_gp_value;
         break;
@@ -244,10 +236,8 @@ MipsReginfoSection<ELFT> *MipsReginfoSection<ELFT>::create() {
       error(toString(Sec->File) + ": invalid size of .reginfo section");
       return nullptr;
     }
-    auto *R = reinterpret_cast<const Elf_Mips_RegInfo *>(Sec->Data.data());
-    if (Config->Relocatable && R->ri_gp_value)
-      error(toString(Sec->File) + ": unsupported non-zero ri_gp_value");
 
+    auto *R = reinterpret_cast<const Elf_Mips_RegInfo *>(Sec->Data.data());
     Reginfo.ri_gprmask |= R->ri_gprmask;
     Sec->getFile<ELFT>()->MipsGp0 = R->ri_gp_value;
   };
@@ -266,8 +256,8 @@ InputSection *elf::createInterpSection() {
   return Sec;
 }
 
-Symbol *elf::addSyntheticLocal(StringRef Name, uint8_t Type, uint64_t Value,
-                               uint64_t Size, InputSectionBase &Section) {
+Defined *elf::addSyntheticLocal(StringRef Name, uint8_t Type, uint64_t Value,
+                                uint64_t Size, InputSectionBase &Section) {
   auto *S = make<Defined>(Section.File, Name, STB_LOCAL, STV_DEFAULT, Type,
                           Value, Size, &Section);
   if (InX::SymTab)
@@ -338,8 +328,6 @@ void BuildIdSection::computeHash(
 BssSection::BssSection(StringRef Name, uint64_t Size, uint32_t Alignment)
     : SyntheticSection(SHF_ALLOC | SHF_WRITE, SHT_NOBITS, Alignment, Name) {
   this->Bss = true;
-  if (OutputSection *Sec = getParent())
-    Sec->Alignment = std::max(Sec->Alignment, Alignment);
   this->Size = Size;
 }
 
@@ -347,7 +335,7 @@ void BuildIdSection::writeBuildId(ArrayRef<uint8_t> Buf) {
   switch (Config->BuildId) {
   case BuildIdKind::Fast:
     computeHash(Buf, [](uint8_t *Dest, ArrayRef<uint8_t> Arr) {
-      write64le(Dest, xxHash64(toStringRef(Arr)));
+      write64le(Dest, xxHash64(Arr));
     });
     break;
   case BuildIdKind::Md5:
@@ -380,15 +368,11 @@ EhFrameSection::EhFrameSection()
 // and where their relocations point to.
 template <class ELFT, class RelTy>
 CieRecord *EhFrameSection::addCie(EhSectionPiece &Cie, ArrayRef<RelTy> Rels) {
-  auto *Sec = cast<EhInputSection>(Cie.Sec);
-  if (read32(Cie.data().data() + 4, Config->Endianness) != 0)
-    fatal(toString(Sec) + ": CIE expected at beginning of .eh_frame");
-
   Symbol *Personality = nullptr;
   unsigned FirstRelI = Cie.FirstRelocation;
   if (FirstRelI != (unsigned)-1)
     Personality =
-        &Sec->template getFile<ELFT>()->getRelocTargetSym(Rels[FirstRelI]);
+        &Cie.Sec->template getFile<ELFT>()->getRelocTargetSym(Rels[FirstRelI]);
 
   // Search for an existing CIE by CIE contents/relocation target pair.
   CieRecord *&Rec = CieMap[{Cie.data(), Personality}];
@@ -433,14 +417,14 @@ bool EhFrameSection::isFdeLive(EhSectionPiece &Fde, ArrayRef<RelTy> Rels) {
 // one and associates FDEs to the CIE.
 template <class ELFT, class RelTy>
 void EhFrameSection::addSectionAux(EhInputSection *Sec, ArrayRef<RelTy> Rels) {
-  DenseMap<size_t, CieRecord *> OffsetToCie;
+  OffsetToCie.clear();
   for (EhSectionPiece &Piece : Sec->Pieces) {
     // The empty record is the end marker.
     if (Piece.Size == 4)
       return;
 
     size_t Offset = Piece.InputOff;
-    uint32_t ID = read32(Piece.data().data() + 4, Config->Endianness);
+    uint32_t ID = read32(Piece.data().data() + 4);
     if (ID == 0) {
       OffsetToCie[Offset] = addCie<ELFT>(Piece, Rels);
       continue;
@@ -468,10 +452,6 @@ template <class ELFT> void EhFrameSection::addSection(InputSectionBase *C) {
   for (auto *DS : Sec->DependentSections)
     DependentSections.push_back(DS);
 
-  // .eh_frame is a sequence of CIE or FDE records. This function
-  // splits it into pieces so that we can call
-  // SplitInputSection::getSectionPiece on the section.
-  Sec->split<ELFT>();
   if (Sec->Pieces.empty())
     return;
 
@@ -494,9 +474,7 @@ static void writeCieFde(uint8_t *Buf, ArrayRef<uint8_t> D) {
 }
 
 void EhFrameSection::finalizeContents() {
-  if (this->Size)
-    return; // Already finalized.
-
+  assert(!this->Size); // Not finalized.
   size_t Off = 0;
   for (CieRecord *Rec : CieRecords) {
     Rec->Cie->OutputOff = Off;
@@ -509,10 +487,10 @@ void EhFrameSection::finalizeContents() {
   }
 
   // The LSB standard does not allow a .eh_frame section with zero
-  // Call Frame Information records. Therefore add a CIE record length
-  // 0 as a terminator if this .eh_frame section is empty.
-  if (Off == 0)
-    Off = 4;
+  // Call Frame Information records. glibc unwind-dw2-fde.c
+  // classify_object_over_fdes expects there is a CIE record length 0 as a
+  // terminator. Thus we add one unconditionally.
+  Off += 4;
 
   this->Size = Off;
 }
@@ -524,25 +502,47 @@ std::vector<EhFrameSection::FdeData> EhFrameSection::getFdeData() const {
   uint8_t *Buf = getParent()->Loc + OutSecOff;
   std::vector<FdeData> Ret;
 
+  uint64_t VA = InX::EhFrameHdr->getVA();
   for (CieRecord *Rec : CieRecords) {
     uint8_t Enc = getFdeEncoding(Rec->Cie);
     for (EhSectionPiece *Fde : Rec->Fdes) {
-      uint32_t Pc = getFdePc(Buf, Fde->OutputOff, Enc);
-      uint32_t FdeVA = getParent()->Addr + Fde->OutputOff;
-      Ret.push_back({Pc, FdeVA});
+      uint64_t Pc = getFdePc(Buf, Fde->OutputOff, Enc);
+      uint64_t FdeVA = getParent()->Addr + Fde->OutputOff;
+      if (!isInt<32>(Pc - VA))
+        fatal(toString(Fde->Sec) + ": PC offset is too large: 0x" +
+              Twine::utohexstr(Pc - VA));
+      Ret.push_back({uint32_t(Pc - VA), uint32_t(FdeVA - VA)});
     }
   }
+
+  // Sort the FDE list by their PC and uniqueify. Usually there is only
+  // one FDE for a PC (i.e. function), but if ICF merges two functions
+  // into one, there can be more than one FDEs pointing to the address.
+  auto Less = [](const FdeData &A, const FdeData &B) {
+    return A.PcRel < B.PcRel;
+  };
+  std::stable_sort(Ret.begin(), Ret.end(), Less);
+  auto Eq = [](const FdeData &A, const FdeData &B) {
+    return A.PcRel == B.PcRel;
+  };
+  Ret.erase(std::unique(Ret.begin(), Ret.end(), Eq), Ret.end());
+
   return Ret;
 }
 
 static uint64_t readFdeAddr(uint8_t *Buf, int Size) {
   switch (Size) {
   case DW_EH_PE_udata2:
-    return read16(Buf, Config->Endianness);
+    return read16(Buf);
+  case DW_EH_PE_sdata2:
+    return (int16_t)read16(Buf);
   case DW_EH_PE_udata4:
-    return read32(Buf, Config->Endianness);
+    return read32(Buf);
+  case DW_EH_PE_sdata4:
+    return (int32_t)read32(Buf);
   case DW_EH_PE_udata8:
-    return read64(Buf, Config->Endianness);
+  case DW_EH_PE_sdata8:
+    return read64(Buf);
   case DW_EH_PE_absptr:
     return readUint(Buf);
   }
@@ -556,7 +556,7 @@ uint64_t EhFrameSection::getFdePc(uint8_t *Buf, size_t FdeOff,
   // The starting address to which this FDE applies is
   // stored at FDE + 8 byte.
   size_t Off = FdeOff + 8;
-  uint64_t Addr = readFdeAddr(Buf + Off, Enc & 0x7);
+  uint64_t Addr = readFdeAddr(Buf + Off, Enc & 0xf);
   if ((Enc & 0x70) == DW_EH_PE_absptr)
     return Addr;
   if ((Enc & 0x70) == DW_EH_PE_pcrel)
@@ -589,7 +589,15 @@ void EhFrameSection::writeTo(uint8_t *Buf) {
 
 GotSection::GotSection()
     : SyntheticSection(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
-                       Target->GotEntrySize, ".got") {}
+                       Target->GotEntrySize, ".got") {
+  // PPC64 saves the ElfSym::GlobalOffsetTable .TOC. as the first entry in the
+  // .got. If there are no references to .TOC. in the symbol table,
+  // ElfSym::GlobalOffsetTable will not be defined and we won't need to save
+  // .TOC. in the .got. When it is defined, we increase NumEntries by the number
+  // of entries used to emit ElfSym::GlobalOffsetTable.
+  if (ElfSym::GlobalOffsetTable && !Target->GotBaseSymInGotPlt)
+    NumEntries += Target->GotHeaderEntriesNum;
+}
 
 void GotSection::addEntry(Symbol &Sym) {
   Sym.GotIndex = NumEntries;
@@ -623,196 +631,383 @@ uint64_t GotSection::getGlobalDynOffset(const Symbol &B) const {
   return B.GlobalDynIndex * Config->Wordsize;
 }
 
-void GotSection::finalizeContents() { Size = NumEntries * Config->Wordsize; }
+void GotSection::finalizeContents() {
+  Size = NumEntries * Config->Wordsize;
+}
 
 bool GotSection::empty() const {
   // We need to emit a GOT even if it's empty if there's a relocation that is
   // relative to GOT(such as GOTOFFREL) or there's a symbol that points to a GOT
-  // (i.e. _GLOBAL_OFFSET_TABLE_).
-  return NumEntries == 0 && !HasGotOffRel && !ElfSym::GlobalOffsetTable;
+  // (i.e. _GLOBAL_OFFSET_TABLE_) that the target defines relative to the .got.
+  return NumEntries == 0 && !HasGotOffRel &&
+         !(ElfSym::GlobalOffsetTable && !Target->GotBaseSymInGotPlt);
 }
 
 void GotSection::writeTo(uint8_t *Buf) {
   // Buf points to the start of this section's buffer,
   // whereas InputSectionBase::relocateAlloc() expects its argument
   // to point to the start of the output section.
+  Target->writeGotHeader(Buf);
   relocateAlloc(Buf - OutSecOff, Buf - OutSecOff + Size);
 }
 
+static uint64_t getMipsPageAddr(uint64_t Addr) {
+  return (Addr + 0x8000) & ~0xffff;
+}
+
+static uint64_t getMipsPageCount(uint64_t Size) {
+  return (Size + 0xfffe) / 0xffff + 1;
+}
+
 MipsGotSection::MipsGotSection()
     : SyntheticSection(SHF_ALLOC | SHF_WRITE | SHF_MIPS_GPREL, SHT_PROGBITS, 16,
                        ".got") {}
 
-void MipsGotSection::addEntry(Symbol &Sym, int64_t Addend, RelExpr Expr) {
-  // For "true" local symbols which can be referenced from the same module
-  // only compiler creates two instructions for address loading:
-  //
-  // lw   $8, 0($gp) # R_MIPS_GOT16
-  // addi $8, $8, 0  # R_MIPS_LO16
-  //
-  // The first instruction loads high 16 bits of the symbol address while
-  // the second adds an offset. That allows to reduce number of required
-  // GOT entries because only one global offset table entry is necessary
-  // for every 64 KBytes of local data. So for local symbols we need to
-  // allocate number of GOT entries to hold all required "page" addresses.
-  //
-  // All global symbols (hidden and regular) considered by compiler uniformly.
-  // It always generates a single `lw` instruction and R_MIPS_GOT16 relocation
-  // to load address of the symbol. So for each such symbol we need to
-  // allocate dedicated GOT entry to store its address.
-  //
-  // If a symbol is preemptible we need help of dynamic linker to get its
-  // final address. The corresponding GOT entries are allocated in the
-  // "global" part of GOT. Entries for non preemptible global symbol allocated
-  // in the "local" part of GOT.
-  //
-  // See "Global Offset Table" in Chapter 5:
-  // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
+void MipsGotSection::addEntry(InputFile &File, Symbol &Sym, int64_t Addend,
+                              RelExpr Expr) {
+  FileGot &G = getGot(File);
   if (Expr == R_MIPS_GOT_LOCAL_PAGE) {
-    // At this point we do not know final symbol value so to reduce number
-    // of allocated GOT entries do the following trick. Save all output
-    // sections referenced by GOT relocations. Then later in the `finalize`
-    // method calculate number of "pages" required to cover all saved output
-    // section and allocate appropriate number of GOT entries.
-    PageIndexMap.insert({Sym.getOutputSection(), 0});
-    return;
-  }
-  if (Sym.isTls()) {
-    // GOT entries created for MIPS TLS relocations behave like
-    // almost GOT entries from other ABIs. They go to the end
-    // of the global offset table.
-    Sym.GotIndex = TlsEntries.size();
-    TlsEntries.push_back(&Sym);
-    return;
-  }
-  auto AddEntry = [&](Symbol &S, uint64_t A, GotEntries &Items) {
-    if (S.isInGot() && !A)
-      return;
-    size_t NewIndex = Items.size();
-    if (!EntryIndexMap.insert({{&S, A}, NewIndex}).second)
-      return;
-    Items.emplace_back(&S, A);
-    if (!A)
-      S.GotIndex = NewIndex;
-  };
-  if (Sym.IsPreemptible) {
-    // Ignore addends for preemptible symbols. They got single GOT entry anyway.
-    AddEntry(Sym, 0, GlobalEntries);
-    Sym.IsInGlobalMipsGot = true;
-  } else if (Expr == R_MIPS_GOT_OFF32) {
-    AddEntry(Sym, Addend, LocalEntries32);
-    Sym.Is32BitMipsGot = true;
-  } else {
-    // Hold local GOT entries accessed via a 16-bit index separately.
-    // That allows to write them in the beginning of the GOT and keep
-    // their indexes as less as possible to escape relocation's overflow.
-    AddEntry(Sym, Addend, LocalEntries);
-  }
+    if (const OutputSection *OS = Sym.getOutputSection())
+      G.PagesMap.insert({OS, {}});
+    else
+      G.Local16.insert({{nullptr, getMipsPageAddr(Sym.getVA(Addend))}, 0});
+  } else if (Sym.isTls())
+    G.Tls.insert({&Sym, 0});
+  else if (Sym.IsPreemptible && Expr == R_ABS)
+    G.Relocs.insert({&Sym, 0});
+  else if (Sym.IsPreemptible)
+    G.Global.insert({&Sym, 0});
+  else if (Expr == R_MIPS_GOT_OFF32)
+    G.Local32.insert({{&Sym, Addend}, 0});
+  else
+    G.Local16.insert({{&Sym, Addend}, 0});
 }
 
-bool MipsGotSection::addDynTlsEntry(Symbol &Sym) {
-  if (Sym.GlobalDynIndex != -1U)
-    return false;
-  Sym.GlobalDynIndex = TlsEntries.size();
-  // Global Dynamic TLS entries take two GOT slots.
-  TlsEntries.push_back(nullptr);
-  TlsEntries.push_back(&Sym);
-  return true;
+void MipsGotSection::addDynTlsEntry(InputFile &File, Symbol &Sym) {
+  getGot(File).DynTlsSymbols.insert({&Sym, 0});
 }
 
-// Reserves TLS entries for a TLS module ID and a TLS block offset.
-// In total it takes two GOT slots.
-bool MipsGotSection::addTlsIndex() {
-  if (TlsIndexOff != uint32_t(-1))
-    return false;
-  TlsIndexOff = TlsEntries.size() * Config->Wordsize;
-  TlsEntries.push_back(nullptr);
-  TlsEntries.push_back(nullptr);
-  return true;
+void MipsGotSection::addTlsIndex(InputFile &File) {
+  getGot(File).DynTlsSymbols.insert({nullptr, 0});
 }
 
-static uint64_t getMipsPageAddr(uint64_t Addr) {
-  return (Addr + 0x8000) & ~0xffff;
+size_t MipsGotSection::FileGot::getEntriesNum() const {
+  return getPageEntriesNum() + Local16.size() + Global.size() + Relocs.size() +
+         Tls.size() + DynTlsSymbols.size() * 2;
 }
 
-static uint64_t getMipsPageCount(uint64_t Size) {
-  return (Size + 0xfffe) / 0xffff + 1;
+size_t MipsGotSection::FileGot::getPageEntriesNum() const {
+  size_t Num = 0;
+  for (const std::pair<const OutputSection *, FileGot::PageBlock> &P : PagesMap)
+    Num += P.second.Count;
+  return Num;
 }
 
-uint64_t MipsGotSection::getPageEntryOffset(const Symbol &B,
-                                            int64_t Addend) const {
-  const OutputSection *OutSec = B.getOutputSection();
-  uint64_t SecAddr = getMipsPageAddr(OutSec->Addr);
-  uint64_t SymAddr = getMipsPageAddr(B.getVA(Addend));
-  uint64_t Index = PageIndexMap.lookup(OutSec) + (SymAddr - SecAddr) / 0xffff;
-  assert(Index < PageEntriesNum);
-  return (HeaderEntriesNum + Index) * Config->Wordsize;
+size_t MipsGotSection::FileGot::getIndexedEntriesNum() const {
+  size_t Count = getPageEntriesNum() + Local16.size() + Global.size();
+  // If there are relocation-only entries in the GOT, TLS entries
+  // are allocated after them. TLS entries should be addressable
+  // by 16-bit index so count both reloc-only and TLS entries.
+  if (!Tls.empty() || !DynTlsSymbols.empty())
+    Count += Relocs.size() + Tls.size() + DynTlsSymbols.size() * 2;
+  return Count;
 }
 
-uint64_t MipsGotSection::getSymEntryOffset(const Symbol &B,
-                                           int64_t Addend) const {
-  // Calculate offset of the GOT entries block: TLS, global, local.
-  uint64_t Index = HeaderEntriesNum + PageEntriesNum;
-  if (B.isTls())
-    Index += LocalEntries.size() + LocalEntries32.size() + GlobalEntries.size();
-  else if (B.IsInGlobalMipsGot)
-    Index += LocalEntries.size() + LocalEntries32.size();
-  else if (B.Is32BitMipsGot)
-    Index += LocalEntries.size();
-  // Calculate offset of the GOT entry in the block.
-  if (B.isInGot())
-    Index += B.GotIndex;
-  else {
-    auto It = EntryIndexMap.find({&B, Addend});
-    assert(It != EntryIndexMap.end());
-    Index += It->second;
+MipsGotSection::FileGot &MipsGotSection::getGot(InputFile &F) {
+  if (!F.MipsGotIndex.hasValue()) {
+    Gots.emplace_back();
+    Gots.back().File = &F;
+    F.MipsGotIndex = Gots.size() - 1;
+  }
+  return Gots[*F.MipsGotIndex];
+}
+
+uint64_t MipsGotSection::getPageEntryOffset(const InputFile *F,
+                                            const Symbol &Sym,
+                                            int64_t Addend) const {
+  const FileGot &G = Gots[*F->MipsGotIndex];
+  uint64_t Index = 0;
+  if (const OutputSection *OutSec = Sym.getOutputSection()) {
+    uint64_t SecAddr = getMipsPageAddr(OutSec->Addr);
+    uint64_t SymAddr = getMipsPageAddr(Sym.getVA(Addend));
+    Index = G.PagesMap.lookup(OutSec).FirstIndex + (SymAddr - SecAddr) / 0xffff;
+  } else {
+    Index = G.Local16.lookup({nullptr, getMipsPageAddr(Sym.getVA(Addend))});
   }
   return Index * Config->Wordsize;
 }
 
-uint64_t MipsGotSection::getTlsOffset() const {
-  return (getLocalEntriesNum() + GlobalEntries.size()) * Config->Wordsize;
+uint64_t MipsGotSection::getSymEntryOffset(const InputFile *F, const Symbol &S,
+                                           int64_t Addend) const {
+  const FileGot &G = Gots[*F->MipsGotIndex];
+  Symbol *Sym = const_cast<Symbol *>(&S);
+  if (Sym->isTls())
+    return G.Tls.lookup(Sym) * Config->Wordsize;
+  if (Sym->IsPreemptible)
+    return G.Global.lookup(Sym) * Config->Wordsize;
+  return G.Local16.lookup({Sym, Addend}) * Config->Wordsize;
+}
+
+uint64_t MipsGotSection::getTlsIndexOffset(const InputFile *F) const {
+  const FileGot &G = Gots[*F->MipsGotIndex];
+  return G.DynTlsSymbols.lookup(nullptr) * Config->Wordsize;
 }
 
-uint64_t MipsGotSection::getGlobalDynOffset(const Symbol &B) const {
-  return B.GlobalDynIndex * Config->Wordsize;
+uint64_t MipsGotSection::getGlobalDynOffset(const InputFile *F,
+                                            const Symbol &S) const {
+  const FileGot &G = Gots[*F->MipsGotIndex];
+  Symbol *Sym = const_cast<Symbol *>(&S);
+  return G.DynTlsSymbols.lookup(Sym) * Config->Wordsize;
 }
 
 const Symbol *MipsGotSection::getFirstGlobalEntry() const {
-  return GlobalEntries.empty() ? nullptr : GlobalEntries.front().first;
+  if (Gots.empty())
+    return nullptr;
+  const FileGot &PrimGot = Gots.front();
+  if (!PrimGot.Global.empty())
+    return PrimGot.Global.front().first;
+  if (!PrimGot.Relocs.empty())
+    return PrimGot.Relocs.front().first;
+  return nullptr;
 }
 
 unsigned MipsGotSection::getLocalEntriesNum() const {
-  return HeaderEntriesNum + PageEntriesNum + LocalEntries.size() +
-         LocalEntries32.size();
+  if (Gots.empty())
+    return HeaderEntriesNum;
+  return HeaderEntriesNum + Gots.front().getPageEntriesNum() +
+         Gots.front().Local16.size();
+}
+
+bool MipsGotSection::tryMergeGots(FileGot &Dst, FileGot &Src, bool IsPrimary) {
+  FileGot Tmp = Dst;
+  set_union(Tmp.PagesMap, Src.PagesMap);
+  set_union(Tmp.Local16, Src.Local16);
+  set_union(Tmp.Global, Src.Global);
+  set_union(Tmp.Relocs, Src.Relocs);
+  set_union(Tmp.Tls, Src.Tls);
+  set_union(Tmp.DynTlsSymbols, Src.DynTlsSymbols);
+
+  size_t Count = IsPrimary ? HeaderEntriesNum : 0;
+  Count += Tmp.getIndexedEntriesNum();
+
+  if (Count * Config->Wordsize > Config->MipsGotSize)
+    return false;
+
+  std::swap(Tmp, Dst);
+  return true;
 }
 
 void MipsGotSection::finalizeContents() { updateAllocSize(); }
 
 bool MipsGotSection::updateAllocSize() {
-  PageEntriesNum = 0;
-  for (std::pair<const OutputSection *, size_t> &P : PageIndexMap) {
-    // For each output section referenced by GOT page relocations calculate
-    // and save into PageIndexMap an upper bound of MIPS GOT entries required
-    // to store page addresses of local symbols. We assume the worst case -
-    // each 64kb page of the output section has at least one GOT relocation
-    // against it. And take in account the case when the section intersects
-    // page boundaries.
-    P.second = PageEntriesNum;
-    PageEntriesNum += getMipsPageCount(P.first->Size);
-  }
-  Size = (getLocalEntriesNum() + GlobalEntries.size() + TlsEntries.size()) *
-         Config->Wordsize;
+  Size = HeaderEntriesNum * Config->Wordsize;
+  for (const FileGot &G : Gots)
+    Size += G.getEntriesNum() * Config->Wordsize;
   return false;
 }
 
+template <class ELFT> void MipsGotSection::build() {
+  if (Gots.empty())
+    return;
+
+  std::vector<FileGot> MergedGots(1);
+
+  // For each GOT move non-preemptible symbols from the `Global`
+  // to `Local16` list. Preemptible symbol might become non-preemptible
+  // one if, for example, it gets a related copy relocation.
+  for (FileGot &Got : Gots) {
+    for (auto &P: Got.Global)
+      if (!P.first->IsPreemptible)
+        Got.Local16.insert({{P.first, 0}, 0});
+    Got.Global.remove_if([&](const std::pair<Symbol *, size_t> &P) {
+      return !P.first->IsPreemptible;
+    });
+  }
+
+  // For each GOT remove "reloc-only" entry if there is "global"
+  // entry for the same symbol. And add local entries which indexed
+  // using 32-bit value at the end of 16-bit entries.
+  for (FileGot &Got : Gots) {
+    Got.Relocs.remove_if([&](const std::pair<Symbol *, size_t> &P) {
+      return Got.Global.count(P.first);
+    });
+    set_union(Got.Local16, Got.Local32);
+    Got.Local32.clear();
+  }
+
+  // Evaluate number of "reloc-only" entries in the resulting GOT.
+  // To do that put all unique "reloc-only" and "global" entries
+  // from all GOTs to the future primary GOT.
+  FileGot *PrimGot = &MergedGots.front();
+  for (FileGot &Got : Gots) {
+    set_union(PrimGot->Relocs, Got.Global);
+    set_union(PrimGot->Relocs, Got.Relocs);
+    Got.Relocs.clear();
+  }
+
+  // Evaluate number of "page" entries in each GOT.
+  for (FileGot &Got : Gots) {
+    for (std::pair<const OutputSection *, FileGot::PageBlock> &P :
+         Got.PagesMap) {
+      const OutputSection *OS = P.first;
+      uint64_t SecSize = 0;
+      for (BaseCommand *Cmd : OS->SectionCommands) {
+        if (auto *ISD = dyn_cast<InputSectionDescription>(Cmd))
+          for (InputSection *IS : ISD->Sections) {
+            uint64_t Off = alignTo(SecSize, IS->Alignment);
+            SecSize = Off + IS->getSize();
+          }
+      }
+      P.second.Count = getMipsPageCount(SecSize);
+    }
+  }
+
+  // Merge GOTs. Try to join as much as possible GOTs but do not exceed
+  // maximum GOT size. At first, try to fill the primary GOT because
+  // the primary GOT can be accessed in the most effective way. If it
+  // is not possible, try to fill the last GOT in the list, and finally
+  // create a new GOT if both attempts failed.
+  for (FileGot &SrcGot : Gots) {
+    InputFile *File = SrcGot.File;
+    if (tryMergeGots(MergedGots.front(), SrcGot, true)) {
+      File->MipsGotIndex = 0;
+    } else {
+      // If this is the first time we failed to merge with the primary GOT,
+      // MergedGots.back() will also be the primary GOT. We must make sure not
+      // to try to merge again with IsPrimary=false, as otherwise, if the
+      // inputs are just right, we could allow the primary GOT to become 1 or 2
+      // words too big due to ignoring the header size.
+      if (MergedGots.size() == 1 ||
+          !tryMergeGots(MergedGots.back(), SrcGot, false)) {
+        MergedGots.emplace_back();
+        std::swap(MergedGots.back(), SrcGot);
+      }
+      File->MipsGotIndex = MergedGots.size() - 1;
+    }
+  }
+  std::swap(Gots, MergedGots);
+
+  // Reduce number of "reloc-only" entries in the primary GOT
+  // by substracting "global" entries exist in the primary GOT.
+  PrimGot = &Gots.front();
+  PrimGot->Relocs.remove_if([&](const std::pair<Symbol *, size_t> &P) {
+    return PrimGot->Global.count(P.first);
+  });
+
+  // Calculate indexes for each GOT entry.
+  size_t Index = HeaderEntriesNum;
+  for (FileGot &Got : Gots) {
+    Got.StartIndex = &Got == PrimGot ? 0 : Index;
+    for (std::pair<const OutputSection *, FileGot::PageBlock> &P :
+         Got.PagesMap) {
+      // For each output section referenced by GOT page relocations calculate
+      // and save into PagesMap an upper bound of MIPS GOT entries required
+      // to store page addresses of local symbols. We assume the worst case -
+      // each 64kb page of the output section has at least one GOT relocation
+      // against it. And take in account the case when the section intersects
+      // page boundaries.
+      P.second.FirstIndex = Index;
+      Index += P.second.Count;
+    }
+    for (auto &P: Got.Local16)
+      P.second = Index++;
+    for (auto &P: Got.Global)
+      P.second = Index++;
+    for (auto &P: Got.Relocs)
+      P.second = Index++;
+    for (auto &P: Got.Tls)
+      P.second = Index++;
+    for (auto &P: Got.DynTlsSymbols) {
+      P.second = Index;
+      Index += 2;
+    }
+  }
+
+  // Update Symbol::GotIndex field to use this
+  // value later in the `sortMipsSymbols` function.
+  for (auto &P : PrimGot->Global)
+    P.first->GotIndex = P.second;
+  for (auto &P : PrimGot->Relocs)
+    P.first->GotIndex = P.second;
+
+  // Create dynamic relocations.
+  for (FileGot &Got : Gots) {
+    // Create dynamic relocations for TLS entries.
+    for (std::pair<Symbol *, size_t> &P : Got.Tls) {
+      Symbol *S = P.first;
+      uint64_t Offset = P.second * Config->Wordsize;
+      if (S->IsPreemptible)
+        InX::RelaDyn->addReloc(Target->TlsGotRel, this, Offset, S);
+    }
+    for (std::pair<Symbol *, size_t> &P : Got.DynTlsSymbols) {
+      Symbol *S = P.first;
+      uint64_t Offset = P.second * Config->Wordsize;
+      if (S == nullptr) {
+        if (!Config->Pic)
+          continue;
+        InX::RelaDyn->addReloc(Target->TlsModuleIndexRel, this, Offset, S);
+      } else {
+        // When building a shared library we still need a dynamic relocation
+        // for the module index. Therefore only checking for
+        // S->IsPreemptible is not sufficient (this happens e.g. for
+        // thread-locals that have been marked as local through a linker script)
+        if (!S->IsPreemptible && !Config->Pic)
+          continue;
+        InX::RelaDyn->addReloc(Target->TlsModuleIndexRel, this, Offset, S);
+        // However, we can skip writing the TLS offset reloc for non-preemptible
+        // symbols since it is known even in shared libraries
+        if (!S->IsPreemptible)
+          continue;
+        Offset += Config->Wordsize;
+        InX::RelaDyn->addReloc(Target->TlsOffsetRel, this, Offset, S);
+      }
+    }
+
+    // Do not create dynamic relocations for non-TLS
+    // entries in the primary GOT.
+    if (&Got == PrimGot)
+      continue;
+
+    // Dynamic relocations for "global" entries.
+    for (const std::pair<Symbol *, size_t> &P : Got.Global) {
+      uint64_t Offset = P.second * Config->Wordsize;
+      InX::RelaDyn->addReloc(Target->RelativeRel, this, Offset, P.first);
+    }
+    if (!Config->Pic)
+      continue;
+    // Dynamic relocations for "local" entries in case of PIC.
+    for (const std::pair<const OutputSection *, FileGot::PageBlock> &L :
+         Got.PagesMap) {
+      size_t PageCount = L.second.Count;
+      for (size_t PI = 0; PI < PageCount; ++PI) {
+        uint64_t Offset = (L.second.FirstIndex + PI) * Config->Wordsize;
+        InX::RelaDyn->addReloc({Target->RelativeRel, this, Offset, L.first,
+                                int64_t(PI * 0x10000)});
+      }
+    }
+    for (const std::pair<GotEntry, size_t> &P : Got.Local16) {
+      uint64_t Offset = P.second * Config->Wordsize;
+      InX::RelaDyn->addReloc({Target->RelativeRel, this, Offset, true,
+                              P.first.first, P.first.second});
+    }
+  }
+}
+
 bool MipsGotSection::empty() const {
   // We add the .got section to the result for dynamic MIPS target because
   // its address and properties are mentioned in the .dynamic section.
   return Config->Relocatable;
 }
 
-uint64_t MipsGotSection::getGp() const { return ElfSym::MipsGp->getVA(0); }
+uint64_t MipsGotSection::getGp(const InputFile *F) const {
+  // For files without related GOT or files refer a primary GOT
+  // returns "common" _gp value. For secondary GOTs calculate
+  // individual _gp values.
+  if (!F || !F->MipsGotIndex.hasValue() || *F->MipsGotIndex == 0)
+    return ElfSym::MipsGp->getVA(0);
+  return getVA() + Gots[*F->MipsGotIndex].StartIndex * Config->Wordsize +
+         0x7ff0;
+}
 
 void MipsGotSection::writeTo(uint8_t *Buf) {
   // Set the MSB of the second GOT slot. This is not required by any
@@ -830,59 +1025,67 @@ void MipsGotSection::writeTo(uint8_t *Buf) {
   // keep doing this for now. We really need to revisit this to see
   // if we had to do this.
   writeUint(Buf + Config->Wordsize, (uint64_t)1 << (Config->Wordsize * 8 - 1));
-  Buf += HeaderEntriesNum * Config->Wordsize;
-  // Write 'page address' entries to the local part of the GOT.
-  for (std::pair<const OutputSection *, size_t> &L : PageIndexMap) {
-    size_t PageCount = getMipsPageCount(L.first->Size);
-    uint64_t FirstPageAddr = getMipsPageAddr(L.first->Addr);
-    for (size_t PI = 0; PI < PageCount; ++PI) {
-      uint8_t *Entry = Buf + (L.second + PI) * Config->Wordsize;
-      writeUint(Entry, FirstPageAddr + PI * 0x10000);
-    }
-  }
-  Buf += PageEntriesNum * Config->Wordsize;
-  auto AddEntry = [&](const GotEntry &SA) {
-    uint8_t *Entry = Buf;
-    Buf += Config->Wordsize;
-    const Symbol *Sym = SA.first;
-    uint64_t VA = Sym->getVA(SA.second);
-    if (Sym->StOther & STO_MIPS_MICROMIPS)
-      VA |= 1;
-    writeUint(Entry, VA);
-  };
-  std::for_each(std::begin(LocalEntries), std::end(LocalEntries), AddEntry);
-  std::for_each(std::begin(LocalEntries32), std::end(LocalEntries32), AddEntry);
-  std::for_each(std::begin(GlobalEntries), std::end(GlobalEntries), AddEntry);
-  // Initialize TLS-related GOT entries. If the entry has a corresponding
-  // dynamic relocations, leave it initialized by zero. Write down adjusted
-  // TLS symbol's values otherwise. To calculate the adjustments use offsets
-  // for thread-local storage.
-  // https://www.linux-mips.org/wiki/NPTL
-  if (TlsIndexOff != -1U && !Config->Pic)
-    writeUint(Buf + TlsIndexOff, 1);
-  for (const Symbol *B : TlsEntries) {
-    if (!B || B->IsPreemptible)
-      continue;
-    uint64_t VA = B->getVA();
-    if (B->GotIndex != -1U) {
-      uint8_t *Entry = Buf + B->GotIndex * Config->Wordsize;
-      writeUint(Entry, VA - 0x7000);
+  for (const FileGot &G : Gots) {
+    auto Write = [&](size_t I, const Symbol *S, int64_t A) {
+      uint64_t VA = A;
+      if (S) {
+        VA = S->getVA(A);
+        if (S->StOther & STO_MIPS_MICROMIPS)
+          VA |= 1;
+      }
+      writeUint(Buf + I * Config->Wordsize, VA);
+    };
+    // Write 'page address' entries to the local part of the GOT.
+    for (const std::pair<const OutputSection *, FileGot::PageBlock> &L :
+         G.PagesMap) {
+      size_t PageCount = L.second.Count;
+      uint64_t FirstPageAddr = getMipsPageAddr(L.first->Addr);
+      for (size_t PI = 0; PI < PageCount; ++PI)
+        Write(L.second.FirstIndex + PI, nullptr, FirstPageAddr + PI * 0x10000);
     }
-    if (B->GlobalDynIndex != -1U) {
-      uint8_t *Entry = Buf + B->GlobalDynIndex * Config->Wordsize;
-      writeUint(Entry, 1);
-      Entry += Config->Wordsize;
-      writeUint(Entry, VA - 0x8000);
+    // Local, global, TLS, reloc-only  entries.
+    // If TLS entry has a corresponding dynamic relocations, leave it
+    // initialized by zero. Write down adjusted TLS symbol's values otherwise.
+    // To calculate the adjustments use offsets for thread-local storage.
+    // https://www.linux-mips.org/wiki/NPTL
+    for (const std::pair<GotEntry, size_t> &P : G.Local16)
+      Write(P.second, P.first.first, P.first.second);
+    // Write VA to the primary GOT only. For secondary GOTs that
+    // will be done by REL32 dynamic relocations.
+    if (&G == &Gots.front())
+      for (const std::pair<const Symbol *, size_t> &P : G.Global)
+        Write(P.second, P.first, 0);
+    for (const std::pair<Symbol *, size_t> &P : G.Relocs)
+      Write(P.second, P.first, 0);
+    for (const std::pair<Symbol *, size_t> &P : G.Tls)
+      Write(P.second, P.first, P.first->IsPreemptible ? 0 : -0x7000);
+    for (const std::pair<Symbol *, size_t> &P : G.DynTlsSymbols) {
+      if (P.first == nullptr && !Config->Pic)
+        Write(P.second, nullptr, 1);
+      else if (P.first && !P.first->IsPreemptible) {
+        // If we are emitting PIC code with relocations we mustn't write
+        // anything to the GOT here. When using Elf_Rel relocations the value
+        // one will be treated as an addend and will cause crashes at runtime
+        if (!Config->Pic)
+          Write(P.second, nullptr, 1);
+        Write(P.second + 1, P.first, -0x8000);
+      }
     }
   }
 }
 
+// On PowerPC the .plt section is used to hold the table of function addresses
+// instead of the .got.plt, and the type is SHT_NOBITS similar to a .bss
+// section. I don't know why we have a BSS style type for the section but it is
+// consitent across both 64-bit PowerPC ABIs as well as the 32-bit PowerPC ABI.
 GotPltSection::GotPltSection()
-    : SyntheticSection(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
-                       Target->GotPltEntrySize, ".got.plt") {}
+    : SyntheticSection(SHF_ALLOC | SHF_WRITE,
+                       Config->EMachine == EM_PPC64 ? SHT_NOBITS : SHT_PROGBITS,
+                       Target->GotPltEntrySize,
+                       Config->EMachine == EM_PPC64 ? ".plt" : ".got.plt") {}
 
 void GotPltSection::addEntry(Symbol &Sym) {
-  Sym.GotPltIndex = Target->GotPltHeaderEntriesNum + Entries.size();
+  assert(Sym.PltIndex == Entries.size());
   Entries.push_back(&Sym);
 }
 
@@ -900,16 +1103,37 @@ void GotPltSection::writeTo(uint8_t *Buf) {
   }
 }
 
-// On ARM the IgotPltSection is part of the GotSection, on other Targets it is
-// part of the .got.plt
+bool GotPltSection::empty() const {
+  // We need to emit a GOT.PLT even if it's empty if there's a symbol that
+  // references the _GLOBAL_OFFSET_TABLE_ and the Target defines the symbol
+  // relative to the .got.plt section.
+  return Entries.empty() &&
+         !(ElfSym::GlobalOffsetTable && Target->GotBaseSymInGotPlt);
+}
+
+static StringRef getIgotPltName() {
+  // On ARM the IgotPltSection is part of the GotSection.
+  if (Config->EMachine == EM_ARM)
+    return ".got";
+
+  // On PowerPC64 the GotPltSection is renamed to '.plt' so the IgotPltSection
+  // needs to be named the same.
+  if (Config->EMachine == EM_PPC64)
+    return ".plt";
+
+  return ".got.plt";
+}
+
+// On PowerPC64 the GotPltSection type is SHT_NOBITS so we have to follow suit
+// with the IgotPltSection.
 IgotPltSection::IgotPltSection()
-    : SyntheticSection(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
-                       Target->GotPltEntrySize,
-                       Config->EMachine == EM_ARM ? ".got" : ".got.plt") {}
+    : SyntheticSection(SHF_ALLOC | SHF_WRITE,
+                       Config->EMachine == EM_PPC64 ? SHT_NOBITS : SHT_PROGBITS,
+                       Target->GotPltEntrySize, getIgotPltName()) {}
 
 void IgotPltSection::addEntry(Symbol &Sym) {
   Sym.IsInIgot = true;
-  Sym.GotPltIndex = Entries.size();
+  assert(Sym.PltIndex == Entries.size());
   Entries.push_back(&Sym);
 }
 
@@ -1005,8 +1229,14 @@ void DynamicSection<ELFT>::addInt(int32_t Tag, uint64_t Val) {
 
 template <class ELFT>
 void DynamicSection<ELFT>::addInSec(int32_t Tag, InputSection *Sec) {
+  Entries.push_back({Tag, [=] { return Sec->getVA(0); }});
+}
+
+template <class ELFT>
+void DynamicSection<ELFT>::addInSecRelative(int32_t Tag, InputSection *Sec) {
+  size_t TagOffset = Entries.size() * Entsize;
   Entries.push_back(
-      {Tag, [=] { return Sec->getParent()->Addr + Sec->OutSecOff; }});
+      {Tag, [=] { return Sec->getVA(0) - (getVA() + TagOffset); }});
 }
 
 template <class ELFT>
@@ -1036,6 +1266,8 @@ template <class ELFT> void DynamicSection<ELFT>::finalizeContents() {
     DtFlags |= DF_SYMBOLIC;
   if (Config->ZInitfirst)
     DtFlags1 |= DF_1_INITFIRST;
+  if (Config->ZInterpose)
+    DtFlags1 |= DF_1_INTERPOSE;
   if (Config->ZNodelete)
     DtFlags1 |= DF_1_NODELETE;
   if (Config->ZNodlopen)
@@ -1048,6 +1280,8 @@ template <class ELFT> void DynamicSection<ELFT>::finalizeContents() {
     DtFlags |= DF_ORIGIN;
     DtFlags1 |= DF_1_ORIGIN;
   }
+  if (!Config->ZText)
+    DtFlags |= DF_TEXTREL;
 
   if (DtFlags)
     addInt(DT_FLAGS, DtFlags);
@@ -1083,6 +1317,14 @@ template <class ELFT> void DynamicSection<ELFT>::finalizeContents() {
         addInt(IsRela ? DT_RELACOUNT : DT_RELCOUNT, NumRelativeRels);
     }
   }
+  if (InX::RelrDyn && !InX::RelrDyn->Relocs.empty()) {
+    addInSec(Config->UseAndroidRelrTags ? DT_ANDROID_RELR : DT_RELR,
+             InX::RelrDyn);
+    addSize(Config->UseAndroidRelrTags ? DT_ANDROID_RELRSZ : DT_RELRSZ,
+            InX::RelrDyn->getParent());
+    addInt(Config->UseAndroidRelrTags ? DT_ANDROID_RELRENT : DT_RELRENT,
+           sizeof(Elf_Relr));
+  }
   // .rel[a].plt section usually consists of two parts, containing plt and
   // iplt relocations. It is possible to have only iplt relocations in the
   // output. In that case RelaPlt is empty and have zero offset, the same offset
@@ -1162,8 +1404,23 @@ template <class ELFT> void DynamicSection<ELFT>::finalizeContents() {
     else
       addInt(DT_MIPS_GOTSYM, InX::DynSymTab->getNumSymbols());
     addInSec(DT_PLTGOT, InX::MipsGot);
-    if (InX::MipsRldMap)
-      addInSec(DT_MIPS_RLD_MAP, InX::MipsRldMap);
+    if (InX::MipsRldMap) {
+      if (!Config->Pie)
+        addInSec(DT_MIPS_RLD_MAP, InX::MipsRldMap);
+      // Store the offset to the .rld_map section
+      // relative to the address of the tag.
+      addInSecRelative(DT_MIPS_RLD_MAP_REL, InX::MipsRldMap);
+    }
+  }
+
+  // Glink dynamic tag is required by the V2 abi if the plt section isn't empty.
+  if (Config->EMachine == EM_PPC64 && !InX::Plt->empty()) {
+    // The Glink tag points to 32 bytes before the first lazy symbol resolution
+    // stub, which starts directly after the header.
+    Entries.push_back({DT_PPC64_GLINK, [=] {
+                         unsigned Offset = Target->PltHeaderSize - 32;
+                         return InX::Plt->getVA(0) + Offset;
+                       }});
   }
 
   addInt(DT_NULL, 0);
@@ -1183,13 +1440,16 @@ template <class ELFT> void DynamicSection<ELFT>::writeTo(uint8_t *Buf) {
 }
 
 uint64_t DynamicReloc::getOffset() const {
-  return InputSec->getOutputSection()->Addr + InputSec->getOffset(OffsetInSec);
+  return InputSec->getVA(OffsetInSec);
 }
 
-int64_t DynamicReloc::getAddend() const {
+int64_t DynamicReloc::computeAddend() const {
   if (UseSymVA)
     return Sym->getVA(Addend);
-  return Addend;
+  if (!OutputSec)
+    return Addend;
+  // See the comment in the DynamicReloc ctor.
+  return getMipsPageAddr(OutputSec->Addr) + Addend;
 }
 
 uint32_t DynamicReloc::getSymIndex() const {
@@ -1204,6 +1464,23 @@ RelocationBaseSection::RelocationBaseSection(StringRef Name, uint32_t Type,
     : SyntheticSection(SHF_ALLOC, Type, Config->Wordsize, Name),
       DynamicTag(DynamicTag), SizeDynamicTag(SizeDynamicTag) {}
 
+void RelocationBaseSection::addReloc(RelType DynType, InputSectionBase *IS,
+                                     uint64_t OffsetInSec, Symbol *Sym) {
+  addReloc({DynType, IS, OffsetInSec, false, Sym, 0});
+}
+
+void RelocationBaseSection::addReloc(RelType DynType,
+                                     InputSectionBase *InputSec,
+                                     uint64_t OffsetInSec, Symbol *Sym,
+                                     int64_t Addend, RelExpr Expr,
+                                     RelType Type) {
+  // Write the addends to the relocated address if required. We skip
+  // it if the written value would be zero.
+  if (Config->WriteAddends && (Expr != R_ADDEND || Addend != 0))
+    InputSec->Relocations.push_back({Expr, Type, OffsetInSec, Addend, Sym});
+  addReloc({DynType, InputSec, OffsetInSec, Expr != R_ADDEND, Sym, Addend});
+}
+
 void RelocationBaseSection::addReloc(const DynamicReloc &Reloc) {
   if (Reloc.Type == Target->RelativeRel)
     ++NumRelativeRelocs;
@@ -1220,23 +1497,17 @@ void RelocationBaseSection::finalizeContents() {
   getParent()->Link = Link;
 }
 
+RelrBaseSection::RelrBaseSection()
+    : SyntheticSection(SHF_ALLOC,
+                       Config->UseAndroidRelrTags ? SHT_ANDROID_RELR : SHT_RELR,
+                       Config->Wordsize, ".relr.dyn") {}
+
 template <class ELFT>
 static void encodeDynamicReloc(typename ELFT::Rela *P,
                                const DynamicReloc &Rel) {
   if (Config->IsRela)
-    P->r_addend = Rel.getAddend();
+    P->r_addend = Rel.computeAddend();
   P->r_offset = Rel.getOffset();
-  if (Config->EMachine == EM_MIPS && Rel.getInputSec() == InX::MipsGot)
-    // The MIPS GOT section contains dynamic relocations that correspond to TLS
-    // entries. These entries are placed after the global and local sections of
-    // the GOT. At the point when we create these relocations, the size of the
-    // global and local sections is unknown, so the offset that we store in the
-    // TLS entry's DynamicReloc is relative to the start of the TLS section of
-    // the GOT, rather than being relative to the start of the GOT. This line of
-    // code adds the size of the global and local sections to the virtual
-    // address computed by getOffset() in order to adjust it into the TLS
-    // section.
-    P->r_offset += InX::MipsGot->getTlsOffset();
   P->setSymbolAndType(Rel.getSymIndex(), Rel.Type, Config->IsMips64EL);
 }
 
@@ -1249,32 +1520,22 @@ RelocationSection<ELFT>::RelocationSection(StringRef Name, bool Sort)
   this->Entsize = Config->IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
 }
 
-template <class ELFT, class RelTy>
-static bool compRelocations(const RelTy &A, const RelTy &B) {
-  bool AIsRel = A.getType(Config->IsMips64EL) == Target->RelativeRel;
-  bool BIsRel = B.getType(Config->IsMips64EL) == Target->RelativeRel;
+static bool compRelocations(const DynamicReloc &A, const DynamicReloc &B) {
+  bool AIsRel = A.Type == Target->RelativeRel;
+  bool BIsRel = B.Type == Target->RelativeRel;
   if (AIsRel != BIsRel)
     return AIsRel;
-
-  return A.getSymbol(Config->IsMips64EL) < B.getSymbol(Config->IsMips64EL);
+  return A.getSymIndex() < B.getSymIndex();
 }
 
 template <class ELFT> void RelocationSection<ELFT>::writeTo(uint8_t *Buf) {
-  uint8_t *BufBegin = Buf;
+  if (Sort)
+    std::stable_sort(Relocs.begin(), Relocs.end(), compRelocations);
+
   for (const DynamicReloc &Rel : Relocs) {
     encodeDynamicReloc<ELFT>(reinterpret_cast<Elf_Rela *>(Buf), Rel);
     Buf += Config->IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
   }
-
-  if (Sort) {
-    if (Config->IsRela)
-      std::stable_sort((Elf_Rela *)BufBegin,
-                       (Elf_Rela *)BufBegin + Relocs.size(),
-                       compRelocations<ELFT, Elf_Rela>);
-    else
-      std::stable_sort((Elf_Rel *)BufBegin, (Elf_Rel *)BufBegin + Relocs.size(),
-                       compRelocations<ELFT, Elf_Rel>);
-  }
 }
 
 template <class ELFT> unsigned RelocationSection<ELFT>::getRelocOffset() {
@@ -1362,10 +1623,10 @@ bool AndroidPackedRelocationSection<ELFT>::updateAllocSize() {
       NonRelatives.push_back(R);
   }
 
-  std::sort(Relatives.begin(), Relatives.end(),
-            [](const Elf_Rel &A, const Elf_Rel &B) {
-              return A.r_offset < B.r_offset;
-            });
+  llvm::sort(Relatives.begin(), Relatives.end(),
+             [](const Elf_Rel &A, const Elf_Rel &B) {
+               return A.r_offset < B.r_offset;
+             });
 
   // Try to find groups of relative relocations which are spaced one word
   // apart from one another. These generally correspond to vtable entries. The
@@ -1443,10 +1704,10 @@ bool AndroidPackedRelocationSection<ELFT>::updateAllocSize() {
   }
 
   // Finally the non-relative relocations.
-  std::sort(NonRelatives.begin(), NonRelatives.end(),
-            [](const Elf_Rela &A, const Elf_Rela &B) {
-              return A.r_offset < B.r_offset;
-            });
+  llvm::sort(NonRelatives.begin(), NonRelatives.end(),
+             [](const Elf_Rela &A, const Elf_Rela &B) {
+               return A.r_offset < B.r_offset;
+             });
   if (!NonRelatives.empty()) {
     Add(NonRelatives.size());
     Add(HasAddendIfRela);
@@ -1469,6 +1730,97 @@ bool AndroidPackedRelocationSection<ELFT>::updateAllocSize() {
   return RelocData.size() != OldSize;
 }
 
+template <class ELFT> RelrSection<ELFT>::RelrSection() {
+  this->Entsize = Config->Wordsize;
+}
+
+template <class ELFT> bool RelrSection<ELFT>::updateAllocSize() {
+  // This function computes the contents of an SHT_RELR packed relocation
+  // section.
+  //
+  // Proposal for adding SHT_RELR sections to generic-abi is here:
+  //   https://groups.google.com/forum/#!topic/generic-abi/bX460iggiKg
+  //
+  // The encoded sequence of Elf64_Relr entries in a SHT_RELR section looks
+  // like [ AAAAAAAA BBBBBBB1 BBBBBBB1 ... AAAAAAAA BBBBBB1 ... ]
+  //
+  // i.e. start with an address, followed by any number of bitmaps. The address
+  // entry encodes 1 relocation. The subsequent bitmap entries encode up to 63
+  // relocations each, at subsequent offsets following the last address entry.
+  //
+  // The bitmap entries must have 1 in the least significant bit. The assumption
+  // here is that an address cannot have 1 in lsb. Odd addresses are not
+  // supported.
+  //
+  // Excluding the least significant bit in the bitmap, each non-zero bit in
+  // the bitmap represents a relocation to be applied to a corresponding machine
+  // word that follows the base address word. The second least significant bit
+  // represents the machine word immediately following the initial address, and
+  // each bit that follows represents the next word, in linear order. As such,
+  // a single bitmap can encode up to 31 relocations in a 32-bit object, and
+  // 63 relocations in a 64-bit object.
+  //
+  // This encoding has a couple of interesting properties:
+  // 1. Looking at any entry, it is clear whether it's an address or a bitmap:
+  //    even means address, odd means bitmap.
+  // 2. Just a simple list of addresses is a valid encoding.
+
+  size_t OldSize = RelrRelocs.size();
+  RelrRelocs.clear();
+
+  // Same as Config->Wordsize but faster because this is a compile-time
+  // constant.
+  const size_t Wordsize = sizeof(typename ELFT::uint);
+
+  // Number of bits to use for the relocation offsets bitmap.
+  // Must be either 63 or 31.
+  const size_t NBits = Wordsize * 8 - 1;
+
+  // Get offsets for all relative relocations and sort them.
+  std::vector<uint64_t> Offsets;
+  for (const RelativeReloc &Rel : Relocs)
+    Offsets.push_back(Rel.getOffset());
+  llvm::sort(Offsets.begin(), Offsets.end());
+
+  // For each leading relocation, find following ones that can be folded
+  // as a bitmap and fold them.
+  for (size_t I = 0, E = Offsets.size(); I < E;) {
+    // Add a leading relocation.
+    RelrRelocs.push_back(Elf_Relr(Offsets[I]));
+    uint64_t Base = Offsets[I] + Wordsize;
+    ++I;
+
+    // Find foldable relocations to construct bitmaps.
+    while (I < E) {
+      uint64_t Bitmap = 0;
+
+      while (I < E) {
+        uint64_t Delta = Offsets[I] - Base;
+
+        // If it is too far, it cannot be folded.
+        if (Delta >= NBits * Wordsize)
+          break;
+
+        // If it is not a multiple of wordsize away, it cannot be folded.
+        if (Delta % Wordsize)
+          break;
+
+        // Fold it.
+        Bitmap |= 1ULL << (Delta / Wordsize);
+        ++I;
+      }
+
+      if (!Bitmap)
+        break;
+
+      RelrRelocs.push_back(Elf_Relr((Bitmap << 1) | 1));
+      Base += NBits * Wordsize;
+    }
+  }
+
+  return RelrRelocs.size() != OldSize;
+}
+
 SymbolTableBaseSection::SymbolTableBaseSection(StringTableSection &StrTabSec)
     : SyntheticSection(StrTabSec.isDynamic() ? (uint64_t)SHF_ALLOC : 0,
                        StrTabSec.isDynamic() ? SHT_DYNSYM : SHT_SYMTAB,
@@ -1484,50 +1836,70 @@ SymbolTableBaseSection::SymbolTableBaseSection(StringTableSection &StrTabSec)
 static bool sortMipsSymbols(const SymbolTableEntry &L,
                             const SymbolTableEntry &R) {
   // Sort entries related to non-local preemptible symbols by GOT indexes.
-  // All other entries go to the first part of GOT in arbitrary order.
-  bool LIsInLocalGot = !L.Sym->IsInGlobalMipsGot;
-  bool RIsInLocalGot = !R.Sym->IsInGlobalMipsGot;
-  if (LIsInLocalGot || RIsInLocalGot)
-    return !RIsInLocalGot;
-  return L.Sym->GotIndex < R.Sym->GotIndex;
+  // All other entries go to the beginning of a dynsym in arbitrary order.
+  if (L.Sym->isInGot() && R.Sym->isInGot())
+    return L.Sym->GotIndex < R.Sym->GotIndex;
+  if (!L.Sym->isInGot() && !R.Sym->isInGot())
+    return false;
+  return !L.Sym->isInGot();
 }
 
 void SymbolTableBaseSection::finalizeContents() {
   getParent()->Link = StrTabSec.getParent()->SectionIndex;
 
+  if (this->Type != SHT_DYNSYM)
+    return;
+
   // If it is a .dynsym, there should be no local symbols, but we need
   // to do a few things for the dynamic linker.
-  if (this->Type == SHT_DYNSYM) {
-    // Section's Info field has the index of the first non-local symbol.
-    // Because the first symbol entry is a null entry, 1 is the first.
-    getParent()->Info = 1;
-
-    if (InX::GnuHashTab) {
-      // NB: It also sorts Symbols to meet the GNU hash table requirements.
-      InX::GnuHashTab->addSymbols(Symbols);
-    } else if (Config->EMachine == EM_MIPS) {
-      std::stable_sort(Symbols.begin(), Symbols.end(), sortMipsSymbols);
-    }
 
-    size_t I = 0;
-    for (const SymbolTableEntry &S : Symbols) S.Sym->DynsymIndex = ++I;
-    return;
+  // Section's Info field has the index of the first non-local symbol.
+  // Because the first symbol entry is a null entry, 1 is the first.
+  getParent()->Info = 1;
+
+  if (InX::GnuHashTab) {
+    // NB: It also sorts Symbols to meet the GNU hash table requirements.
+    InX::GnuHashTab->addSymbols(Symbols);
+  } else if (Config->EMachine == EM_MIPS) {
+    std::stable_sort(Symbols.begin(), Symbols.end(), sortMipsSymbols);
   }
+
+  size_t I = 0;
+  for (const SymbolTableEntry &S : Symbols)
+    S.Sym->DynsymIndex = ++I;
 }
 
 // The ELF spec requires that all local symbols precede global symbols, so we
 // sort symbol entries in this function. (For .dynsym, we don't do that because
 // symbols for dynamic linking are inherently all globals.)
+//
+// Aside from above, we put local symbols in groups starting with the STT_FILE
+// symbol. That is convenient for purpose of identifying where are local symbols
+// coming from.
 void SymbolTableBaseSection::postThunkContents() {
-  if (this->Type == SHT_DYNSYM)
-    return;
-  // move all local symbols before global symbols.
-  auto It = std::stable_partition(
+  assert(this->Type == SHT_SYMTAB);
+
+  // Move all local symbols before global symbols.
+  auto E = std::stable_partition(
       Symbols.begin(), Symbols.end(), [](const SymbolTableEntry &S) {
         return S.Sym->isLocal() || S.Sym->computeBinding() == STB_LOCAL;
       });
-  size_t NumLocals = It - Symbols.begin();
+  size_t NumLocals = E - Symbols.begin();
   getParent()->Info = NumLocals + 1;
+
+  // We want to group the local symbols by file. For that we rebuild the local
+  // part of the symbols vector. We do not need to care about the STT_FILE
+  // symbols, they are already naturally placed first in each group. That
+  // happens because STT_FILE is always the first symbol in the object and hence
+  // precede all other local symbols we add for a file.
+  MapVector<InputFile *, std::vector<SymbolTableEntry>> Arr;
+  for (const SymbolTableEntry &S : llvm::make_range(Symbols.begin(), E))
+    Arr[S.Sym->File].push_back(S);
+
+  auto I = Symbols.begin();
+  for (std::pair<InputFile *, std::vector<SymbolTableEntry>> &P : Arr)
+    for (SymbolTableEntry &Entry : P.second)
+      *I++ = Entry;
 }
 
 void SymbolTableBaseSection::addSymbol(Symbol *B) {
@@ -1565,6 +1937,23 @@ SymbolTableSection<ELFT>::SymbolTableSection(StringTableSection &StrTabSec)
   this->Entsize = sizeof(Elf_Sym);
 }
 
+static BssSection *getCommonSec(Symbol *Sym) {
+  if (!Config->DefineCommon)
+    if (auto *D = dyn_cast<Defined>(Sym))
+      return dyn_cast_or_null<BssSection>(D->Section);
+  return nullptr;
+}
+
+static uint32_t getSymSectionIndex(Symbol *Sym) {
+  if (getCommonSec(Sym))
+    return SHN_COMMON;
+  if (!isa<Defined>(Sym) || Sym->NeedsPltAddr)
+    return SHN_UNDEF;
+  if (const OutputSection *OS = Sym->getOutputSection())
+    return OS->SectionIndex >= SHN_LORESERVE ? SHN_XINDEX : OS->SectionIndex;
+  return SHN_ABS;
+}
+
 // Write the internal symbol table contents to the output symbol table.
 template <class ELFT> void SymbolTableSection<ELFT>::writeTo(uint8_t *Buf) {
   // The first entry is a null entry as per the ELF spec.
@@ -1586,20 +1975,7 @@ template <class ELFT> void SymbolTableSection<ELFT>::writeTo(uint8_t *Buf) {
     }
 
     ESym->st_name = Ent.StrTabOffset;
-
-    // Set a section index.
-    BssSection *CommonSec = nullptr;
-    if (!Config->DefineCommon)
-      if (auto *D = dyn_cast<Defined>(Sym))
-        CommonSec = dyn_cast_or_null<BssSection>(D->Section);
-    if (CommonSec)
-      ESym->st_shndx = SHN_COMMON;
-    else if (const OutputSection *OutSec = Sym->getOutputSection())
-      ESym->st_shndx = OutSec->SectionIndex;
-    else if (isa<Defined>(Sym))
-      ESym->st_shndx = SHN_ABS;
-    else
-      ESym->st_shndx = SHN_UNDEF;
+    ESym->st_shndx = getSymSectionIndex(Ent.Sym);
 
     // Copy symbol size if it is a defined symbol. st_size is not significant
     // for undefined symbols, so whether copying it or not is up to us if that's
@@ -1614,7 +1990,7 @@ template <class ELFT> void SymbolTableSection<ELFT>::writeTo(uint8_t *Buf) {
     // st_value is usually an address of a symbol, but that has a
     // special meaining for uninstantiated common symbols (this can
     // occur if -r is given).
-    if (CommonSec)
+    if (BssSection *CommonSec = getCommonSec(Ent.Sym))
       ESym->st_value = CommonSec->Alignment;
     else
       ESym->st_value = Sym->getVA();
@@ -1635,9 +2011,11 @@ template <class ELFT> void SymbolTableSection<ELFT>::writeTo(uint8_t *Buf) {
         ESym->st_other |= STO_MIPS_PLT;
       if (isMicroMips()) {
         // Set STO_MIPS_MICROMIPS flag and less-significant bit for
-        // defined microMIPS symbols and shared symbols with PLT record.
-        if ((Sym->isDefined() && (Sym->StOther & STO_MIPS_MICROMIPS)) ||
-            (Sym->isShared() && Sym->NeedsPltAddr)) {
+        // a defined microMIPS symbol and symbol should point to its
+        // PLT entry (in case of microMIPS, PLT entries always contain
+        // microMIPS code).
+        if (Sym->isDefined() &&
+            ((Sym->StOther & STO_MIPS_MICROMIPS) || Sym->NeedsPltAddr)) {
           if (StrTabSec.isDynamic())
             ESym->st_value |= 1;
           ESym->st_other |= STO_MIPS_MICROMIPS;
@@ -1652,6 +2030,44 @@ template <class ELFT> void SymbolTableSection<ELFT>::writeTo(uint8_t *Buf) {
   }
 }
 
+SymtabShndxSection::SymtabShndxSection()
+    : SyntheticSection(0, SHT_SYMTAB_SHNDX, 4, ".symtab_shndxr") {
+  this->Entsize = 4;
+}
+
+void SymtabShndxSection::writeTo(uint8_t *Buf) {
+  // We write an array of 32 bit values, where each value has 1:1 association
+  // with an entry in .symtab. If the corresponding entry contains SHN_XINDEX,
+  // we need to write actual index, otherwise, we must write SHN_UNDEF(0).
+  Buf += 4; // Ignore .symtab[0] entry.
+  for (const SymbolTableEntry &Entry : InX::SymTab->getSymbols()) {
+    if (getSymSectionIndex(Entry.Sym) == SHN_XINDEX)
+      write32(Buf, Entry.Sym->getOutputSection()->SectionIndex);
+    Buf += 4;
+  }
+}
+
+bool SymtabShndxSection::empty() const {
+  // SHT_SYMTAB can hold symbols with section indices values up to
+  // SHN_LORESERVE. If we need more, we want to use extension SHT_SYMTAB_SHNDX
+  // section. Problem is that we reveal the final section indices a bit too
+  // late, and we do not know them here. For simplicity, we just always create
+  // a .symtab_shndxr section when the amount of output sections is huge.
+  size_t Size = 0;
+  for (BaseCommand *Base : Script->SectionCommands)
+    if (isa<OutputSection>(Base))
+      ++Size;
+  return Size < SHN_LORESERVE;
+}
+
+void SymtabShndxSection::finalizeContents() {
+  getParent()->Link = InX::SymTab->getParent()->SectionIndex;
+}
+
+size_t SymtabShndxSection::getSize() const {
+  return InX::SymTab->getNumSymbols() * 4;
+}
+
 // .hash and .gnu.hash sections contain on-disk hash tables that map
 // symbol names to their dynamic symbol table indices. Their purpose
 // is to help the dynamic linker resolve symbols quickly. If ELF files
@@ -1690,12 +2106,14 @@ GnuHashTableSection::GnuHashTableSection()
 void GnuHashTableSection::finalizeContents() {
   getParent()->Link = InX::DynSymTab->getParent()->SectionIndex;
 
-  // Computes bloom filter size in word size. We want to allocate 8
+  // Computes bloom filter size in word size. We want to allocate 12
   // bits for each symbol. It must be a power of two.
-  if (Symbols.empty())
+  if (Symbols.empty()) {
     MaskWords = 1;
-  else
-    MaskWords = NextPowerOf2((Symbols.size() - 1) / Config->Wordsize);
+  } else {
+    uint64_t NumBits = Symbols.size() * 12;
+    MaskWords = NextPowerOf2(NumBits / (Config->Wordsize * 8));
+  }
 
   Size = 16;                            // Header
   Size += Config->Wordsize * MaskWords; // Bloom filter
@@ -1713,7 +2131,7 @@ void GnuHashTableSection::writeTo(uint8_t *Buf) {
   write32(Buf, NBuckets);
   write32(Buf + 4, InX::DynSymTab->getNumSymbols() - Symbols.size());
   write32(Buf + 8, MaskWords);
-  write32(Buf + 12, getShift2());
+  write32(Buf + 12, Shift2);
   Buf += 16;
 
   // Write a bloom filter and a hash table.
@@ -1730,12 +2148,12 @@ void GnuHashTableSection::writeTo(uint8_t *Buf) {
 // [1] Ulrich Drepper (2011), "How To Write Shared Libraries" (Ver. 4.1.2),
 //     p.9, https://www.akkadia.org/drepper/dsohowto.pdf
 void GnuHashTableSection::writeBloomFilter(uint8_t *Buf) {
-  const unsigned C = Config->Wordsize * 8;
+  unsigned C = Config->Is64 ? 64 : 32;
   for (const Entry &Sym : Symbols) {
     size_t I = (Sym.Hash / C) & (MaskWords - 1);
     uint64_t Val = readUint(Buf + I * Config->Wordsize);
     Val |= uint64_t(1) << (Sym.Hash % C);
-    Val |= uint64_t(1) << ((Sym.Hash >> getShift2()) % C);
+    Val |= uint64_t(1) << ((Sym.Hash >> Shift2) % C);
     writeUint(Buf + I * Config->Wordsize, Val);
   }
 }
@@ -1777,21 +2195,23 @@ void GnuHashTableSection::addSymbols(std::vector<SymbolTableEntry> &V) {
   // its type correctly.
   std::vector<SymbolTableEntry>::iterator Mid =
       std::stable_partition(V.begin(), V.end(), [](const SymbolTableEntry &S) {
-        // Shared symbols that this executable preempts are special. The dynamic
-        // linker has to look them up, so they have to be in the hash table.
-        if (auto *SS = dyn_cast<SharedSymbol>(S.Sym))
-          return SS->CopyRelSec == nullptr && !SS->NeedsPltAddr;
         return !S.Sym->isDefined();
       });
-  if (Mid == V.end())
-    return;
 
   // We chose load factor 4 for the on-disk hash table. For each hash
   // collision, the dynamic linker will compare a uint32_t hash value.
-  // Since the integer comparison is quite fast, we believe we can make
-  // the load factor even larger. 4 is just a conservative choice.
+  // Since the integer comparison is quite fast, we believe we can
+  // make the load factor even larger. 4 is just a conservative choice.
+  //
+  // Note that we don't want to create a zero-sized hash table because
+  // Android loader as of 2018 doesn't like a .gnu.hash containing such
+  // table. If that's the case, we create a hash table with one unused
+  // dummy slot.
   NBuckets = std::max<size_t>((V.end() - Mid) / 4, 1);
 
+  if (Mid == V.end())
+    return;
+
   for (SymbolTableEntry &Ent : llvm::make_range(Mid, V.end())) {
     Symbol *B = Ent.Sym;
     uint32_t Hash = hashGnu(B->getName());
@@ -1847,9 +2267,12 @@ void HashTableSection::writeTo(uint8_t *Buf) {
   }
 }
 
-PltSection::PltSection(size_t S)
-    : SyntheticSection(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS, 16, ".plt"),
-      HeaderSize(S) {
+// On PowerPC64 the lazy symbol resolvers go into the `global linkage table`
+// in the .glink section, rather then the typical .plt section.
+PltSection::PltSection(bool IsIplt)
+    : SyntheticSection(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS, 16,
+                       Config->EMachine == EM_PPC64 ? ".glink" : ".plt"),
+      HeaderSize(IsIplt ? 0 : Target->PltHeaderSize), IsIplt(IsIplt) {
   // The PLT needs to be writable on SPARC as the dynamic linker will
   // modify the instructions in the PLT entries.
   if (Config->EMachine == EM_SPARCV9)
@@ -1859,7 +2282,7 @@ PltSection::PltSection(size_t S)
 void PltSection::writeTo(uint8_t *Buf) {
   // At beginning of PLT but not the IPLT, we have code to call the dynamic
   // linker to resolve dynsyms at runtime. Write such code.
-  if (HeaderSize != 0)
+  if (!IsIplt)
     Target->writePltHeader(Buf);
   size_t Off = HeaderSize;
   // The IPlt is immediately after the Plt, account for this in RelOff
@@ -1878,7 +2301,7 @@ void PltSection::writeTo(uint8_t *Buf) {
 template <class ELFT> void PltSection::addEntry(Symbol &Sym) {
   Sym.PltIndex = Entries.size();
   RelocationBaseSection *PltRelocSection = InX::RelaPlt;
-  if (HeaderSize == 0) {
+  if (IsIplt) {
     PltRelocSection = InX::RelaIplt;
     Sym.IsInIplt = true;
   }
@@ -1895,7 +2318,7 @@ size_t PltSection::getSize() const {
 // example ARM uses mapping symbols to aid disassembly
 void PltSection::addSymbols() {
   // The PLT may have symbols defined for the Header, the IPLT has no header
-  if (HeaderSize != 0)
+  if (!IsIplt)
     Target->addPltHeaderSymbols(*this);
   size_t Off = HeaderSize;
   for (size_t I = 0; I < Entries.size(); ++I) {
@@ -1905,7 +2328,7 @@ void PltSection::addSymbols() {
 }
 
 unsigned PltSection::getPltRelocOff() const {
-  return (HeaderSize == 0) ? InX::Plt->getSize() : 0;
+  return IsIplt ? InX::Plt->getSize() : 0;
 }
 
 // The string hash function for .gdb_index.
@@ -1916,16 +2339,48 @@ static uint32_t computeGdbHash(StringRef S) {
   return H;
 }
 
-static std::vector<GdbIndexChunk::CuEntry> readCuList(DWARFContext &Dwarf) {
-  std::vector<GdbIndexChunk::CuEntry> Ret;
+GdbIndexSection::GdbIndexSection()
+    : SyntheticSection(0, SHT_PROGBITS, 1, ".gdb_index") {}
+
+// Returns the desired size of an on-disk hash table for a .gdb_index section.
+// There's a tradeoff between size and collision rate. We aim 75% utilization.
+size_t GdbIndexSection::computeSymtabSize() const {
+  return std::max<size_t>(NextPowerOf2(Symbols.size() * 4 / 3), 1024);
+}
+
+// Compute the output section size.
+void GdbIndexSection::initOutputSize() {
+  Size = sizeof(GdbIndexHeader) + computeSymtabSize() * 8;
+
+  for (GdbChunk &Chunk : Chunks)
+    Size += Chunk.CompilationUnits.size() * 16 + Chunk.AddressAreas.size() * 20;
+
+  // Add the constant pool size if exists.
+  if (!Symbols.empty()) {
+    GdbSymbol &Sym = Symbols.back();
+    Size += Sym.NameOff + Sym.Name.size() + 1;
+  }
+}
+
+static std::vector<InputSection *> getDebugInfoSections() {
+  std::vector<InputSection *> Ret;
+  for (InputSectionBase *S : InputSections)
+    if (InputSection *IS = dyn_cast<InputSection>(S))
+      if (IS->Name == ".debug_info")
+        Ret.push_back(IS);
+  return Ret;
+}
+
+static std::vector<GdbIndexSection::CuEntry> readCuList(DWARFContext &Dwarf) {
+  std::vector<GdbIndexSection::CuEntry> Ret;
   for (std::unique_ptr<DWARFCompileUnit> &Cu : Dwarf.compile_units())
     Ret.push_back({Cu->getOffset(), Cu->getLength() + 4});
   return Ret;
 }
 
-static std::vector<GdbIndexChunk::AddressEntry>
+static std::vector<GdbIndexSection::AddressEntry>
 readAddressAreas(DWARFContext &Dwarf, InputSection *Sec) {
-  std::vector<GdbIndexChunk::AddressEntry> Ret;
+  std::vector<GdbIndexSection::AddressEntry> Ret;
 
   uint32_t CuIdx = 0;
   for (std::unique_ptr<DWARFCompileUnit> &Cu : Dwarf.compile_units()) {
@@ -1949,218 +2404,192 @@ readAddressAreas(DWARFContext &Dwarf, InputSection *Sec) {
   return Ret;
 }
 
-static std::vector<GdbIndexChunk::NameTypeEntry>
-readPubNamesAndTypes(DWARFContext &Dwarf) {
+static std::vector<GdbIndexSection::NameTypeEntry>
+readPubNamesAndTypes(DWARFContext &Dwarf, uint32_t Idx) {
   StringRef Sec1 = Dwarf.getDWARFObj().getGnuPubNamesSection();
   StringRef Sec2 = Dwarf.getDWARFObj().getGnuPubTypesSection();
 
-  std::vector<GdbIndexChunk::NameTypeEntry> Ret;
+  std::vector<GdbIndexSection::NameTypeEntry> Ret;
   for (StringRef Sec : {Sec1, Sec2}) {
     DWARFDebugPubTable Table(Sec, Config->IsLE, true);
-    for (const DWARFDebugPubTable::Set &Set : Table.getData()) {
-      for (const DWARFDebugPubTable::Entry &Ent : Set.Entries) {
-        CachedHashStringRef S(Ent.Name, computeGdbHash(Ent.Name));
-        Ret.push_back({S, Ent.Descriptor.toBits()});
-      }
-    }
+    for (const DWARFDebugPubTable::Set &Set : Table.getData())
+      for (const DWARFDebugPubTable::Entry &Ent : Set.Entries)
+        Ret.push_back({{Ent.Name, computeGdbHash(Ent.Name)},
+                       (Ent.Descriptor.toBits() << 24) | Idx});
   }
   return Ret;
 }
 
-static std::vector<InputSection *> getDebugInfoSections() {
-  std::vector<InputSection *> Ret;
-  for (InputSectionBase *S : InputSections)
-    if (InputSection *IS = dyn_cast<InputSection>(S))
-      if (IS->Name == ".debug_info")
-        Ret.push_back(IS);
-  return Ret;
-}
+// Create a list of symbols from a given list of symbol names and types
+// by uniquifying them by name.
+static std::vector<GdbIndexSection::GdbSymbol>
+createSymbols(ArrayRef<std::vector<GdbIndexSection::NameTypeEntry>> NameTypes) {
+  typedef GdbIndexSection::GdbSymbol GdbSymbol;
+  typedef GdbIndexSection::NameTypeEntry NameTypeEntry;
 
-void GdbIndexSection::fixCuIndex() {
-  uint32_t Idx = 0;
-  for (GdbIndexChunk &Chunk : Chunks) {
-    for (GdbIndexChunk::AddressEntry &Ent : Chunk.AddressAreas)
-      Ent.CuIndex += Idx;
-    Idx += Chunk.CompilationUnits.size();
-  }
-}
+  // The number of symbols we will handle in this function is of the order
+  // of millions for very large executables, so we use multi-threading to
+  // speed it up.
+  size_t NumShards = 32;
+  size_t Concurrency = 1;
+  if (ThreadsEnabled)
+    Concurrency =
+        std::min<size_t>(PowerOf2Floor(hardware_concurrency()), NumShards);
 
-std::vector<std::vector<uint32_t>> GdbIndexSection::createCuVectors() {
-  std::vector<std::vector<uint32_t>> Ret;
-  uint32_t Idx = 0;
-  uint32_t Off = 0;
+  // A sharded map to uniquify symbols by name.
+  std::vector<DenseMap<CachedHashStringRef, size_t>> Map(NumShards);
+  size_t Shift = 32 - countTrailingZeros(NumShards);
 
-  for (GdbIndexChunk &Chunk : Chunks) {
-    for (GdbIndexChunk::NameTypeEntry &Ent : Chunk.NamesAndTypes) {
-      GdbSymbol *&Sym = Symbols[Ent.Name];
-      if (!Sym) {
-        Sym = make<GdbSymbol>(GdbSymbol{Ent.Name.hash(), Off, Ret.size()});
-        Off += Ent.Name.size() + 1;
-        Ret.push_back({});
-      }
+  // Instantiate GdbSymbols while uniqufying them by name.
+  std::vector<std::vector<GdbSymbol>> Symbols(NumShards);
+  parallelForEachN(0, Concurrency, [&](size_t ThreadId) {
+    for (ArrayRef<NameTypeEntry> Entries : NameTypes) {
+      for (const NameTypeEntry &Ent : Entries) {
+        size_t ShardId = Ent.Name.hash() >> Shift;
+        if ((ShardId & (Concurrency - 1)) != ThreadId)
+          continue;
+
+        size_t &Idx = Map[ShardId][Ent.Name];
+        if (Idx) {
+          Symbols[ShardId][Idx - 1].CuVector.push_back(Ent.Type);
+          continue;
+        }
 
-      // gcc 5.4.1 produces a buggy .debug_gnu_pubnames that contains
-      // duplicate entries, so we want to dedup them.
-      std::vector<uint32_t> &Vec = Ret[Sym->CuVectorIndex];
-      uint32_t Val = (Ent.Type << 24) | Idx;
-      if (Vec.empty() || Vec.back() != Val)
-        Vec.push_back(Val);
+        Idx = Symbols[ShardId].size() + 1;
+        Symbols[ShardId].push_back({Ent.Name, {Ent.Type}, 0, 0});
+      }
     }
-    Idx += Chunk.CompilationUnits.size();
+  });
+
+  size_t NumSymbols = 0;
+  for (ArrayRef<GdbSymbol> V : Symbols)
+    NumSymbols += V.size();
+
+  // The return type is a flattened vector, so we'll copy each vector
+  // contents to Ret.
+  std::vector<GdbSymbol> Ret;
+  Ret.reserve(NumSymbols);
+  for (std::vector<GdbSymbol> &Vec : Symbols)
+    for (GdbSymbol &Sym : Vec)
+      Ret.push_back(std::move(Sym));
+
+  // CU vectors and symbol names are adjacent in the output file.
+  // We can compute their offsets in the output file now.
+  size_t Off = 0;
+  for (GdbSymbol &Sym : Ret) {
+    Sym.CuVectorOff = Off;
+    Off += (Sym.CuVector.size() + 1) * 4;
+  }
+  for (GdbSymbol &Sym : Ret) {
+    Sym.NameOff = Off;
+    Off += Sym.Name.size() + 1;
   }
 
-  StringPoolSize = Off;
   return Ret;
 }
 
-template <class ELFT> GdbIndexSection *elf::createGdbIndex() {
-  // Gather debug info to create a .gdb_index section.
+// Returns a newly-created .gdb_index section.
+template <class ELFT> GdbIndexSection *GdbIndexSection::create() {
   std::vector<InputSection *> Sections = getDebugInfoSections();
-  std::vector<GdbIndexChunk> Chunks(Sections.size());
-
-  parallelForEachN(0, Chunks.size(), [&](size_t I) {
-    ObjFile<ELFT> *File = Sections[I]->getFile<ELFT>();
-    DWARFContext Dwarf(make_unique<LLDDwarfObj<ELFT>>(File));
-
-    Chunks[I].DebugInfoSec = Sections[I];
-    Chunks[I].CompilationUnits = readCuList(Dwarf);
-    Chunks[I].AddressAreas = readAddressAreas(Dwarf, Sections[I]);
-    Chunks[I].NamesAndTypes = readPubNamesAndTypes(Dwarf);
-  });
 
   // .debug_gnu_pub{names,types} are useless in executables.
   // They are present in input object files solely for creating
-  // a .gdb_index. So we can remove it from the output.
+  // a .gdb_index. So we can remove them from the output.
   for (InputSectionBase *S : InputSections)
     if (S->Name == ".debug_gnu_pubnames" || S->Name == ".debug_gnu_pubtypes")
       S->Live = false;
 
-  // Create a .gdb_index and returns it.
-  return make<GdbIndexSection>(std::move(Chunks));
-}
+  std::vector<GdbChunk> Chunks(Sections.size());
+  std::vector<std::vector<NameTypeEntry>> NameTypes(Sections.size());
 
-static size_t getCuSize(ArrayRef<GdbIndexChunk> Arr) {
-  size_t Ret = 0;
-  for (const GdbIndexChunk &D : Arr)
-    Ret += D.CompilationUnits.size();
-  return Ret;
-}
-
-static size_t getAddressAreaSize(ArrayRef<GdbIndexChunk> Arr) {
-  size_t Ret = 0;
-  for (const GdbIndexChunk &D : Arr)
-    Ret += D.AddressAreas.size();
-  return Ret;
-}
-
-std::vector<GdbSymbol *> GdbIndexSection::createGdbSymtab() {
-  uint32_t Size = NextPowerOf2(Symbols.size() * 4 / 3);
-  if (Size < 1024)
-    Size = 1024;
-
-  uint32_t Mask = Size - 1;
-  std::vector<GdbSymbol *> Ret(Size);
+  parallelForEachN(0, Sections.size(), [&](size_t I) {
+    ObjFile<ELFT> *File = Sections[I]->getFile<ELFT>();
+    DWARFContext Dwarf(make_unique<LLDDwarfObj<ELFT>>(File));
 
-  for (auto &KV : Symbols) {
-    GdbSymbol *Sym = KV.second;
-    uint32_t I = Sym->NameHash & Mask;
-    uint32_t Step = ((Sym->NameHash * 17) & Mask) | 1;
+    Chunks[I].Sec = Sections[I];
+    Chunks[I].CompilationUnits = readCuList(Dwarf);
+    Chunks[I].AddressAreas = readAddressAreas(Dwarf, Sections[I]);
+    NameTypes[I] = readPubNamesAndTypes(Dwarf, I);
+  });
 
-    while (Ret[I])
-      I = (I + Step) & Mask;
-    Ret[I] = Sym;
-  }
+  auto *Ret = make<GdbIndexSection>();
+  Ret->Chunks = std::move(Chunks);
+  Ret->Symbols = createSymbols(NameTypes);
+  Ret->initOutputSize();
   return Ret;
 }
 
-GdbIndexSection::GdbIndexSection(std::vector<GdbIndexChunk> &&C)
-    : SyntheticSection(0, SHT_PROGBITS, 1, ".gdb_index"), Chunks(std::move(C)) {
-  fixCuIndex();
-  CuVectors = createCuVectors();
-  GdbSymtab = createGdbSymtab();
-
-  // Compute offsets early to know the section size.
-  // Each chunk size needs to be in sync with what we write in writeTo.
-  CuTypesOffset = CuListOffset + getCuSize(Chunks) * 16;
-  SymtabOffset = CuTypesOffset + getAddressAreaSize(Chunks) * 20;
-  ConstantPoolOffset = SymtabOffset + GdbSymtab.size() * 8;
-
-  size_t Off = 0;
-  for (ArrayRef<uint32_t> Vec : CuVectors) {
-    CuVectorOffsets.push_back(Off);
-    Off += (Vec.size() + 1) * 4;
-  }
-  StringPoolOffset = ConstantPoolOffset + Off;
-}
-
-size_t GdbIndexSection::getSize() const {
-  return StringPoolOffset + StringPoolSize;
-}
-
 void GdbIndexSection::writeTo(uint8_t *Buf) {
-  // Write the section header.
-  write32le(Buf, 7);
-  write32le(Buf + 4, CuListOffset);
-  write32le(Buf + 8, CuTypesOffset);
-  write32le(Buf + 12, CuTypesOffset);
-  write32le(Buf + 16, SymtabOffset);
-  write32le(Buf + 20, ConstantPoolOffset);
-  Buf += 24;
+  // Write the header.
+  auto *Hdr = reinterpret_cast<GdbIndexHeader *>(Buf);
+  uint8_t *Start = Buf;
+  Hdr->Version = 7;
+  Buf += sizeof(*Hdr);
 
   // Write the CU list.
-  for (GdbIndexChunk &D : Chunks) {
-    for (GdbIndexChunk::CuEntry &Cu : D.CompilationUnits) {
-      write64le(Buf, D.DebugInfoSec->OutSecOff + Cu.CuOffset);
+  Hdr->CuListOff = Buf - Start;
+  for (GdbChunk &Chunk : Chunks) {
+    for (CuEntry &Cu : Chunk.CompilationUnits) {
+      write64le(Buf, Chunk.Sec->OutSecOff + Cu.CuOffset);
       write64le(Buf + 8, Cu.CuLength);
       Buf += 16;
     }
   }
 
   // Write the address area.
-  for (GdbIndexChunk &D : Chunks) {
-    for (GdbIndexChunk::AddressEntry &E : D.AddressAreas) {
-      uint64_t BaseAddr =
-          E.Section->getParent()->Addr + E.Section->getOffset(0);
+  Hdr->CuTypesOff = Buf - Start;
+  Hdr->AddressAreaOff = Buf - Start;
+  uint32_t CuOff = 0;
+  for (GdbChunk &Chunk : Chunks) {
+    for (AddressEntry &E : Chunk.AddressAreas) {
+      uint64_t BaseAddr = E.Section->getVA(0);
       write64le(Buf, BaseAddr + E.LowAddress);
       write64le(Buf + 8, BaseAddr + E.HighAddress);
-      write32le(Buf + 16, E.CuIndex);
+      write32le(Buf + 16, E.CuIndex + CuOff);
       Buf += 20;
     }
+    CuOff += Chunk.CompilationUnits.size();
   }
 
-  // Write the symbol table.
-  for (GdbSymbol *Sym : GdbSymtab) {
-    if (Sym) {
-      write32le(Buf, Sym->NameOffset + StringPoolOffset - ConstantPoolOffset);
-      write32le(Buf + 4, CuVectorOffsets[Sym->CuVectorIndex]);
-    }
-    Buf += 8;
+  // Write the on-disk open-addressing hash table containing symbols.
+  Hdr->SymtabOff = Buf - Start;
+  size_t SymtabSize = computeSymtabSize();
+  uint32_t Mask = SymtabSize - 1;
+
+  for (GdbSymbol &Sym : Symbols) {
+    uint32_t H = Sym.Name.hash();
+    uint32_t I = H & Mask;
+    uint32_t Step = ((H * 17) & Mask) | 1;
+
+    while (read32le(Buf + I * 8))
+      I = (I + Step) & Mask;
+
+    write32le(Buf + I * 8, Sym.NameOff);
+    write32le(Buf + I * 8 + 4, Sym.CuVectorOff);
   }
 
+  Buf += SymtabSize * 8;
+
+  // Write the string pool.
+  Hdr->ConstantPoolOff = Buf - Start;
+  for (GdbSymbol &Sym : Symbols)
+    memcpy(Buf + Sym.NameOff, Sym.Name.data(), Sym.Name.size());
+
   // Write the CU vectors.
-  for (ArrayRef<uint32_t> Vec : CuVectors) {
-    write32le(Buf, Vec.size());
+  for (GdbSymbol &Sym : Symbols) {
+    write32le(Buf, Sym.CuVector.size());
     Buf += 4;
-    for (uint32_t Val : Vec) {
+    for (uint32_t Val : Sym.CuVector) {
       write32le(Buf, Val);
       Buf += 4;
     }
   }
-
-  // Write the string pool.
-  for (auto &KV : Symbols) {
-    CachedHashStringRef S = KV.first;
-    GdbSymbol *Sym = KV.second;
-    size_t Off = Sym->NameOffset;
-    memcpy(Buf + Off, S.val().data(), S.size());
-    Buf[Off + S.size()] = '\0';
-  }
 }
 
 bool GdbIndexSection::empty() const { return !Out::DebugInfo; }
 
 EhFrameHeader::EhFrameHeader()
-    : SyntheticSection(SHF_ALLOC, SHT_PROGBITS, 1, ".eh_frame_hdr") {}
+    : SyntheticSection(SHF_ALLOC, SHT_PROGBITS, 4, ".eh_frame_hdr") {}
 
 // .eh_frame_hdr contains a binary search table of pointers to FDEs.
 // Each entry of the search table consists of two values,
@@ -2171,14 +2600,6 @@ void EhFrameHeader::writeTo(uint8_t *Buf) {
 
   std::vector<FdeData> Fdes = InX::EhFrame->getFdeData();
 
-  // Sort the FDE list by their PC and uniqueify. Usually there is only
-  // one FDE for a PC (i.e. function), but if ICF merges two functions
-  // into one, there can be more than one FDEs pointing to the address.
-  auto Less = [](const FdeData &A, const FdeData &B) { return A.Pc < B.Pc; };
-  std::stable_sort(Fdes.begin(), Fdes.end(), Less);
-  auto Eq = [](const FdeData &A, const FdeData &B) { return A.Pc == B.Pc; };
-  Fdes.erase(std::unique(Fdes.begin(), Fdes.end(), Eq), Fdes.end());
-
   Buf[0] = 1;
   Buf[1] = DW_EH_PE_pcrel | DW_EH_PE_sdata4;
   Buf[2] = DW_EH_PE_udata4;
@@ -2187,10 +2608,9 @@ void EhFrameHeader::writeTo(uint8_t *Buf) {
   write32(Buf + 8, Fdes.size());
   Buf += 12;
 
-  uint64_t VA = this->getVA();
   for (FdeData &Fde : Fdes) {
-    write32(Buf, Fde.Pc - VA);
-    write32(Buf + 4, Fde.FdeVA - VA);
+    write32(Buf, Fde.PcRel);
+    write32(Buf + 4, Fde.FdeVARel);
     Buf += 8;
   }
 }
@@ -2300,11 +2720,9 @@ VersionNeedSection<ELFT>::VersionNeedSection()
   NextIndex = getVerDefNum() + 1;
 }
 
-template <class ELFT>
-void VersionNeedSection<ELFT>::addSymbol(SharedSymbol *SS) {
-  SharedFile<ELFT> &File = SS->getFile<ELFT>();
-  const typename ELFT::Verdef *Ver = File.Verdefs[SS->VerdefIndex];
-  if (!Ver) {
+template <class ELFT> void VersionNeedSection<ELFT>::addSymbol(Symbol *SS) {
+  auto &File = cast<SharedFile<ELFT>>(*SS->File);
+  if (SS->VerdefIndex == VER_NDX_GLOBAL) {
     SS->VersionId = VER_NDX_GLOBAL;
     return;
   }
@@ -2314,7 +2732,9 @@ void VersionNeedSection<ELFT>::addSymbol(SharedSymbol *SS) {
   // for the soname.
   if (File.VerdefMap.empty())
     Needed.push_back({&File, InX::DynStrTab->addString(File.SoName)});
+  const typename ELFT::Verdef *Ver = File.Verdefs[SS->VerdefIndex];
   typename SharedFile<ELFT>::NeededVer &NV = File.VerdefMap[Ver];
+
   // If we don't already know that we need an Elf_Vernaux for this Elf_Verdef,
   // prepare to create one by allocating a version identifier and creating a
   // dynstr entry for the version name.
@@ -2478,11 +2898,20 @@ static MergeSyntheticSection *createMergeSynthetic(StringRef Name,
   return make<MergeNoTailSection>(Name, Type, Flags, Alignment);
 }
 
-// Debug sections may be compressed by zlib. Uncompress if exists.
+// Debug sections may be compressed by zlib. Decompress if exists.
 void elf::decompressSections() {
+  parallelForEach(InputSections,
+                  [](InputSectionBase *Sec) { Sec->maybeDecompress(); });
+}
+
+template <class ELFT> void elf::splitSections() {
+  // splitIntoPieces needs to be called on each MergeInputSection
+  // before calling finalizeContents().
   parallelForEach(InputSections, [](InputSectionBase *Sec) {
-    if (Sec->Live)
-      Sec->maybeUncompress();
+    if (auto *S = dyn_cast<MergeInputSection>(Sec))
+      S->splitIntoPieces();
+    else if (auto *Eh = dyn_cast<EhInputSection>(Sec))
+      Eh->split<ELFT>();
   });
 }
 
@@ -2494,14 +2923,6 @@ void elf::decompressSections() {
 // that it replaces. It then finalizes each synthetic section in order
 // to compute an output offset for each piece of each input section.
 void elf::mergeSections() {
-  // splitIntoPieces needs to be called on each MergeInputSection
-  // before calling finalizeContents(). Do that first.
-  parallelForEach(InputSections, [](InputSectionBase *Sec) {
-    if (Sec->Live)
-      if (auto *S = dyn_cast<MergeInputSection>(Sec))
-        S->splitIntoPieces();
-  });
-
   std::vector<MergeSyntheticSection *> MergeSections;
   for (InputSectionBase *&S : InputSections) {
     MergeInputSection *MS = dyn_cast<MergeInputSection>(S);
@@ -2510,8 +2931,10 @@ void elf::mergeSections() {
 
     // We do not want to handle sections that are not alive, so just remove
     // them instead of trying to merge.
-    if (!MS->Live)
+    if (!MS->Live) {
+      S = nullptr;
       continue;
+    }
 
     StringRef OutsecName = getOutputSectionName(MS);
     uint32_t Alignment = MS->Alignment;
@@ -2565,8 +2988,7 @@ ARMExidxSentinelSection::ARMExidxSentinelSection()
 // address described by any other table entry.
 void ARMExidxSentinelSection::writeTo(uint8_t *Buf) {
   assert(Highest);
-  uint64_t S =
-      Highest->getParent()->Addr + Highest->getOffset(Highest->getSize());
+  uint64_t S = Highest->getVA(Highest->getSize());
   uint64_t P = getVA();
   Target->relocateOne(Buf, R_ARM_PREL31, S - P);
   write32le(Buf + 4, 1);
@@ -2574,18 +2996,16 @@ void ARMExidxSentinelSection::writeTo(uint8_t *Buf) {
 
 // The sentinel has to be removed if there are no other .ARM.exidx entries.
 bool ARMExidxSentinelSection::empty() const {
-  OutputSection *OS = getParent();
-  if (!OS)
-    return false;
-
-  for (auto *B : OS->SectionCommands)
-    if (auto *ISD = dyn_cast<InputSectionDescription>(B))
-      for (auto *S : ISD->Sections)
-        if (!isa<ARMExidxSentinelSection>(S))
-          return false;
+  for (InputSection *IS : getInputSections(getParent()))
+    if (!isa<ARMExidxSentinelSection>(IS))
+      return false;
   return true;
 }
 
+bool ARMExidxSentinelSection::classof(const SectionBase *D) {
+  return D->kind() == InputSectionBase::Synthetic && D->Type == SHT_ARM_EXIDX;
+}
+
 ThunkSection::ThunkSection(OutputSection *OS, uint64_t Off)
     : SyntheticSection(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS,
                        Config->Wordsize, ".text.thunk") {
@@ -2594,16 +3014,13 @@ ThunkSection::ThunkSection(OutputSection *OS, uint64_t Off)
 }
 
 void ThunkSection::addThunk(Thunk *T) {
-  uint64_t Off = alignTo(Size, T->Alignment);
-  T->Offset = Off;
   Thunks.push_back(T);
   T->addSymbols(*this);
-  Size = Off + T->size();
 }
 
 void ThunkSection::writeTo(uint8_t *Buf) {
-  for (const Thunk *T : Thunks)
-    T->writeTo(Buf + T->Offset, *this);
+  for (Thunk *T : Thunks)
+    T->writeTo(Buf + T->Offset);
 }
 
 InputSection *ThunkSection::getTargetInputSection() const {
@@ -2613,6 +3030,20 @@ InputSection *ThunkSection::getTargetInputSection() const {
   return T->getTargetInputSection();
 }
 
+bool ThunkSection::assignOffsets() {
+  uint64_t Off = 0;
+  for (Thunk *T : Thunks) {
+    Off = alignTo(Off, T->Alignment);
+    T->setOffset(Off);
+    uint32_t Size = T->size();
+    T->getThunkTargetSym()->Size = Size;
+    Off += Size;
+  }
+  bool Changed = Off != Size;
+  Size = Off;
+  return Changed;
+}
+
 InputSection *InX::ARMAttributes;
 BssSection *InX::Bss;
 BssSection *InX::BssRelRo;
@@ -2634,16 +3065,23 @@ MipsRldMapSection *InX::MipsRldMap;
 PltSection *InX::Plt;
 PltSection *InX::Iplt;
 RelocationBaseSection *InX::RelaDyn;
+RelrBaseSection *InX::RelrDyn;
 RelocationBaseSection *InX::RelaPlt;
 RelocationBaseSection *InX::RelaIplt;
 StringTableSection *InX::ShStrTab;
 StringTableSection *InX::StrTab;
 SymbolTableBaseSection *InX::SymTab;
+SymtabShndxSection *InX::SymTabShndx;
+
+template GdbIndexSection *GdbIndexSection::create<ELF32LE>();
+template GdbIndexSection *GdbIndexSection::create<ELF32BE>();
+template GdbIndexSection *GdbIndexSection::create<ELF64LE>();
+template GdbIndexSection *GdbIndexSection::create<ELF64BE>();
 
-template GdbIndexSection *elf::createGdbIndex<ELF32LE>();
-template GdbIndexSection *elf::createGdbIndex<ELF32BE>();
-template GdbIndexSection *elf::createGdbIndex<ELF64LE>();
-template GdbIndexSection *elf::createGdbIndex<ELF64BE>();
+template void elf::splitSections<ELF32LE>();
+template void elf::splitSections<ELF32BE>();
+template void elf::splitSections<ELF64LE>();
+template void elf::splitSections<ELF64BE>();
 
 template void EhFrameSection::addSection<ELF32LE>(InputSectionBase *);
 template void EhFrameSection::addSection<ELF32BE>(InputSectionBase *);
@@ -2655,6 +3093,11 @@ template void PltSection::addEntry<ELF32BE>(Symbol &Sym);
 template void PltSection::addEntry<ELF64LE>(Symbol &Sym);
 template void PltSection::addEntry<ELF64BE>(Symbol &Sym);
 
+template void MipsGotSection::build<ELF32LE>();
+template void MipsGotSection::build<ELF32BE>();
+template void MipsGotSection::build<ELF64LE>();
+template void MipsGotSection::build<ELF64BE>();
+
 template class elf::MipsAbiFlagsSection<ELF32LE>;
 template class elf::MipsAbiFlagsSection<ELF32BE>;
 template class elf::MipsAbiFlagsSection<ELF64LE>;
@@ -2685,6 +3128,11 @@ template class elf::AndroidPackedRelocationSection<ELF32BE>;
 template class elf::AndroidPackedRelocationSection<ELF64LE>;
 template class elf::AndroidPackedRelocationSection<ELF64BE>;
 
+template class elf::RelrSection<ELF32LE>;
+template class elf::RelrSection<ELF32BE>;
+template class elf::RelrSection<ELF64LE>;
+template class elf::RelrSection<ELF64BE>;
+
 template class elf::SymbolTableSection<ELF32LE>;
 template class elf::SymbolTableSection<ELF32BE>;
 template class elf::SymbolTableSection<ELF64LE>;
diff --git a/gnu/llvm/tools/lld/ELF/Writer.cpp b/gnu/llvm/tools/lld/ELF/Writer.cpp
index 058aa178771..ccff0c58333 100644
--- a/gnu/llvm/tools/lld/ELF/Writer.cpp
+++ b/gnu/llvm/tools/lld/ELF/Writer.cpp
@@ -9,18 +9,19 @@
 
 #include "Writer.h"
 #include "AArch64ErrataFix.h"
+#include "CallGraphSort.h"
 #include "Config.h"
 #include "Filesystem.h"
 #include "LinkerScript.h"
 #include "MapFile.h"
 #include "OutputSections.h"
 #include "Relocations.h"
-#include "Strings.h"
 #include "SymbolTable.h"
 #include "Symbols.h"
 #include "SyntheticSections.h"
 #include "Target.h"
 #include "lld/Common/Memory.h"
+#include "lld/Common/Strings.h"
 #include "lld/Common/Threads.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringSwitch.h"
@@ -49,7 +50,7 @@ public:
 private:
   void copyLocalSymbols();
   void addSectionSymbols();
-  void forEachRelSec(std::function<void(InputSectionBase &)> Fn);
+  void forEachRelSec(llvm::function_ref<void(InputSectionBase &)> Fn);
   void sortSections();
   void resolveShfLinkOrder();
   void sortInputSections();
@@ -62,6 +63,7 @@ private:
   void assignFileOffsets();
   void assignFileOffsetsBinary();
   void setPhdrs();
+  void checkSections();
   void fixSectionAlignments();
   void openFile();
   void writeTrapInstr();
@@ -81,40 +83,49 @@ private:
 
   uint64_t FileSize;
   uint64_t SectionHeaderOff;
-
-  bool HasGotBaseSym = false;
 };
 } // anonymous namespace
 
-StringRef elf::getOutputSectionName(InputSectionBase *S) {
-  // ".zdebug_" is a prefix for ZLIB-compressed sections.
-  // Because we decompressed input sections, we want to remove 'z'.
-  if (S->Name.startswith(".zdebug_"))
-    return Saver.save("." + S->Name.substr(2));
+static bool isSectionPrefix(StringRef Prefix, StringRef Name) {
+  return Name.startswith(Prefix) || Name == Prefix.drop_back();
+}
 
+StringRef elf::getOutputSectionName(const InputSectionBase *S) {
   if (Config->Relocatable)
     return S->Name;
 
   // This is for --emit-relocs. If .text.foo is emitted as .text.bar, we want
   // to emit .rela.text.foo as .rela.text.bar for consistency (this is not
   // technically required, but not doing it is odd). This code guarantees that.
-  if ((S->Type == SHT_REL || S->Type == SHT_RELA) &&
-      !isa<SyntheticSection>(S)) {
-    OutputSection *Out =
-        cast<InputSection>(S)->getRelocatedSection()->getOutputSection();
-    if (S->Type == SHT_RELA)
-      return Saver.save(".rela" + Out->Name);
-    return Saver.save(".rel" + Out->Name);
+  if (auto *IS = dyn_cast<InputSection>(S)) {
+    if (InputSectionBase *Rel = IS->getRelocatedSection()) {
+      OutputSection *Out = Rel->getOutputSection();
+      if (S->Type == SHT_RELA)
+        return Saver.save(".rela" + Out->Name);
+      return Saver.save(".rel" + Out->Name);
+    }
   }
 
+  // This check is for -z keep-text-section-prefix.  This option separates text
+  // sections with prefix ".text.hot", ".text.unlikely", ".text.startup" or
+  // ".text.exit".
+  // When enabled, this allows identifying the hot code region (.text.hot) in
+  // the final binary which can be selectively mapped to huge pages or mlocked,
+  // for instance.
+  if (Config->ZKeepTextSectionPrefix)
+    for (StringRef V :
+         {".text.hot.", ".text.unlikely.", ".text.startup.", ".text.exit."}) {
+      if (isSectionPrefix(V, S->Name))
+        return V.drop_back();
+    }
+
   for (StringRef V :
        {".text.", ".rodata.", ".data.rel.ro.", ".data.", ".bss.rel.ro.",
         ".bss.", ".init_array.", ".fini_array.", ".ctors.", ".dtors.", ".tbss.",
         ".gcc_except_table.", ".tdata.", ".ARM.exidx.", ".ARM.extab.",
-	".openbsd.randomdata."}) {
-    StringRef Prefix = V.drop_back();
-    if (S->Name.startswith(V) || S->Name == Prefix)
-      return Prefix;
+        ".openbsd.randomdata."}) {
+    if (isSectionPrefix(V, S->Name))
+      return V.drop_back();
   }
 
   // CommonSection is identified as "COMMON" in linker scripts.
@@ -195,21 +206,30 @@ void elf::addReservedSymbols() {
           Symtab->addAbsolute("__gnu_local_gp", STV_HIDDEN, STB_GLOBAL);
   }
 
+  // The Power Architecture 64-bit v2 ABI defines a TableOfContents (TOC) which
+  // combines the typical ELF GOT with the small data sections. It commonly
+  // includes .got .toc .sdata .sbss. The .TOC. symbol replaces both
+  // _GLOBAL_OFFSET_TABLE_ and _SDA_BASE_ from the 32-bit ABI. It is used to
+  // represent the TOC base which is offset by 0x8000 bytes from the start of
+  // the .got section.
   ElfSym::GlobalOffsetTable = addOptionalRegular(
-      "_GLOBAL_OFFSET_TABLE_", Out::ElfHeader, Target->GotBaseSymOff);
+      (Config->EMachine == EM_PPC64) ? ".TOC." : "_GLOBAL_OFFSET_TABLE_",
+      Out::ElfHeader, Target->GotBaseSymOff);
 
   // __ehdr_start is the location of ELF file headers. Note that we define
   // this symbol unconditionally even when using a linker script, which
   // differs from the behavior implemented by GNU linker which only define
   // this symbol if ELF headers are in the memory mapped segment.
+  addOptionalRegular("__ehdr_start", Out::ElfHeader, 0, STV_HIDDEN);
+
   // __executable_start is not documented, but the expectation of at
-  // least the android libc is that it points to the elf header too.
+  // least the Android libc is that it points to the ELF header.
+  addOptionalRegular("__executable_start", Out::ElfHeader, 0, STV_HIDDEN);
+
   // __dso_handle symbol is passed to cxa_finalize as a marker to identify
   // each DSO. The address of the symbol doesn't matter as long as they are
   // different in different DSOs, so we chose the start address of the DSO.
-  for (const char *Name :
-       {"__ehdr_start", "__executable_start", "__dso_handle"})
-    addOptionalRegular(Name, Out::ElfHeader, 0, STV_HIDDEN);
+  addOptionalRegular("__dso_handle", Out::ElfHeader, 0, STV_HIDDEN);
 
   // If linker script do layout we do not need to create any standart symbols.
   if (Script->HasSectionsCommand)
@@ -269,6 +289,7 @@ template <class ELFT> static void createSyntheticSections() {
   if (Config->Strip != StripPolicy::All) {
     InX::StrTab = make<StringTableSection>(".strtab", false);
     InX::SymTab = make<SymbolTableSection<ELFT>>(*InX::StrTab);
+    InX::SymTabShndx = make<SymtabShndxSection>();
   }
 
   if (Config->BuildId != BuildIdKind::None) {
@@ -282,10 +303,9 @@ template <class ELFT> static void createSyntheticSections() {
   // If there is a SECTIONS command and a .data.rel.ro section name use name
   // .data.rel.ro.bss so that we match in the .data.rel.ro output section.
   // This makes sure our relro is contiguous.
-  bool HasDataRelRo =
-      Script->HasSectionsCommand && findSection(".data.rel.ro");
-  InX::BssRelRo = make<BssSection>(
-      HasDataRelRo ? ".data.rel.ro.bss" : ".bss.rel.ro", 0, 1);
+  bool HasDataRelRo = Script->HasSectionsCommand && findSection(".data.rel.ro");
+  InX::BssRelRo =
+      make<BssSection>(HasDataRelRo ? ".data.rel.ro.bss" : ".bss.rel.ro", 0, 1);
   Add(InX::BssRelRo);
 
   // Add MIPS-specific sections.
@@ -332,6 +352,11 @@ template <class ELFT> static void createSyntheticSections() {
     Add(InX::RelaDyn);
   }
 
+  if (Config->RelrPackDynRelocs) {
+    InX::RelrDyn = make<RelrSection<ELFT>>();
+    Add(InX::RelrDyn);
+  }
+
   // Add .got. MIPS' .got is so different from the other archs,
   // it has its own class.
   if (Config->EMachine == EM_MIPS) {
@@ -348,7 +373,7 @@ template <class ELFT> static void createSyntheticSections() {
   Add(InX::IgotPlt);
 
   if (Config->GdbIndex) {
-    InX::GdbIndex = createGdbIndex<ELFT>();
+    InX::GdbIndex = GdbIndexSection::create<ELFT>();
     Add(InX::GdbIndex);
   }
 
@@ -371,9 +396,9 @@ template <class ELFT> static void createSyntheticSections() {
       false /*Sort*/);
   Add(InX::RelaIplt);
 
-  InX::Plt = make<PltSection>(Target->PltHeaderSize);
+  InX::Plt = make<PltSection>(false);
   Add(InX::Plt);
-  InX::Iplt = make<PltSection>(0);
+  InX::Iplt = make<PltSection>(true);
   Add(InX::Iplt);
 
   if (!Config->Relocatable) {
@@ -387,6 +412,8 @@ template <class ELFT> static void createSyntheticSections() {
 
   if (InX::SymTab)
     Add(InX::SymTab);
+  if (InX::SymTabShndx)
+    Add(InX::SymTabShndx);
   Add(InX::ShStrTab);
   if (InX::StrTab)
     Add(InX::StrTab);
@@ -456,6 +483,9 @@ template <class ELFT> void Writer<ELFT>::run() {
       Sec->Addr = 0;
   }
 
+  if (Config->CheckSections)
+    checkSections();
+
   // It does not make sense try to open the file if we have error already.
   if (errorCount())
     return;
@@ -478,8 +508,9 @@ template <class ELFT> void Writer<ELFT>::run() {
   if (errorCount())
     return;
 
-  // Handle -Map option.
+  // Handle -Map and -cref options.
   writeMapFile();
+  writeCrossReferenceTable();
   if (errorCount())
     return;
 
@@ -492,10 +523,6 @@ static bool shouldKeepInSymtab(SectionBase *Sec, StringRef SymName,
   if (B.isSection())
     return false;
 
-  // If sym references a section in a discarded group, don't keep it.
-  if (Sec == &InputSection::Discarded)
-    return false;
-
   if (Config->Discard == DiscardPolicy::None)
     return true;
 
@@ -640,6 +667,9 @@ static bool isRelroSection(const OutputSection *Sec) {
   if (InX::Got && Sec == InX::Got->getParent())
     return true;
 
+  if (Sec->Name.equals(".toc"))
+    return true;
+
   // .got.plt contains pointers to external function symbols. They are
   // by default resolved lazily, so we usually cannot put it into RELRO.
   // However, if "-z now" is given, the lazy symbol resolution is
@@ -675,20 +705,22 @@ static bool isRelroSection(const OutputSection *Sec) {
 // * It is easy to check if a give branch was taken.
 // * It is easy two see how similar two ranks are (see getRankProximity).
 enum RankFlags {
-  RF_NOT_ADDR_SET = 1 << 16,
-  RF_NOT_INTERP = 1 << 15,
-  RF_NOT_ALLOC = 1 << 14,
-  RF_WRITE = 1 << 13,
-  RF_EXEC_WRITE = 1 << 12,
-  RF_EXEC = 1 << 11,
-  RF_NON_TLS_BSS = 1 << 10,
-  RF_NON_TLS_BSS_RO = 1 << 9,
-  RF_NOT_TLS = 1 << 8,
-  RF_BSS = 1 << 7,
+  RF_NOT_ADDR_SET = 1 << 18,
+  RF_NOT_INTERP = 1 << 17,
+  RF_NOT_ALLOC = 1 << 16,
+  RF_WRITE = 1 << 15,
+  RF_EXEC_WRITE = 1 << 14,
+  RF_EXEC = 1 << 13,
+  RF_RODATA = 1 << 12,
+  RF_NON_TLS_BSS = 1 << 11,
+  RF_NON_TLS_BSS_RO = 1 << 10,
+  RF_NOT_TLS = 1 << 9,
+  RF_BSS = 1 << 8,
+  RF_NOTE = 1 << 7,
   RF_PPC_NOT_TOCBSS = 1 << 6,
-  RF_PPC_OPD = 1 << 5,
-  RF_PPC_TOCL = 1 << 4,
-  RF_PPC_TOC = 1 << 3,
+  RF_PPC_TOCL = 1 << 5,
+  RF_PPC_TOC = 1 << 4,
+  RF_PPC_GOT = 1 << 3,
   RF_PPC_BRANCH_LT = 1 << 2,
   RF_MIPS_GPREL = 1 << 1,
   RF_MIPS_NOT_GOT = 1 << 0
@@ -719,8 +751,7 @@ static unsigned getSectionRank(const OutputSection *Sec) {
   // considerations:
   // * Read-only sections come first such that they go in the
   //   PT_LOAD covering the program headers at the start of the file.
-  // * Read-only, executable sections come next, unless the
-  //   -no-rosegment option is used.
+  // * Read-only, executable sections come next.
   // * Writable, executable sections follow such that .plt on
   //   architectures where it needs to be writable will be placed
   //   between .text and .data.
@@ -732,11 +763,16 @@ static unsigned getSectionRank(const OutputSection *Sec) {
   if (IsExec) {
     if (IsWrite)
       Rank |= RF_EXEC_WRITE;
-    else if (!Config->SingleRoRx)
+    else
       Rank |= RF_EXEC;
-  } else {
-    if (IsWrite)
-      Rank |= RF_WRITE;
+  } else if (IsWrite) {
+    Rank |= RF_WRITE;
+  } else if (Sec->Type == SHT_PROGBITS) {
+    // Make non-executable and non-writable PROGBITS sections (e.g .rodata
+    // .eh_frame) closer to .text. They likely contain PC or GOT relative
+    // relocations and there could be relocation overflow if other huge sections
+    // (.dynstr .dynsym) were placed in between.
+    Rank |= RF_RODATA;
   }
 
   // If we got here we know that both A and B are in the same PT_LOAD.
@@ -772,6 +808,12 @@ static unsigned getSectionRank(const OutputSection *Sec) {
   if (IsNoBits)
     Rank |= RF_BSS;
 
+  // We create a NOTE segment for contiguous .note sections, so make
+  // them contigous if there are more than one .note section with the
+  // same attributes.
+  if (Sec->Type == SHT_NOTE)
+    Rank |= RF_NOTE;
+
   // Some architectures have additional ordering restrictions for sections
   // within the same PT_LOAD.
   if (Config->EMachine == EM_PPC64) {
@@ -785,18 +827,19 @@ static unsigned getSectionRank(const OutputSection *Sec) {
     if (Name != ".tocbss")
       Rank |= RF_PPC_NOT_TOCBSS;
 
-    if (Name == ".opd")
-      Rank |= RF_PPC_OPD;
-
     if (Name == ".toc1")
       Rank |= RF_PPC_TOCL;
 
     if (Name == ".toc")
       Rank |= RF_PPC_TOC;
 
+    if (Name == ".got")
+      Rank |= RF_PPC_GOT;
+
     if (Name == ".branch_lt")
       Rank |= RF_PPC_BRANCH_LT;
   }
+
   if (Config->EMachine == EM_MIPS) {
     // All sections with SHF_MIPS_GPREL flag should be grouped together
     // because data in these sections is addressable with a gp relative address.
@@ -828,8 +871,6 @@ void PhdrEntry::add(OutputSection *Sec) {
   p_align = std::max(p_align, Sec->Alignment);
   if (p_type == PT_LOAD)
     Sec->PtLoad = this;
-  if (Sec->LMAExpr)
-    ASectionHasLMA = true;
 }
 
 // The beginning and the ending of .rel[a].plt section are marked
@@ -839,17 +880,19 @@ void PhdrEntry::add(OutputSection *Sec) {
 // need these symbols, since IRELATIVE relocs are resolved through GOT
 // and PLT. For details, see http://www.airs.com/blog/archives/403.
 template <class ELFT> void Writer<ELFT>::addRelIpltSymbols() {
-  if (!Config->Static)
+  if (Config->Relocatable || needsInterpSection())
     return;
   StringRef S = Config->IsRela ? "__rela_iplt_start" : "__rel_iplt_start";
   addOptionalRegular(S, InX::RelaIplt, 0, STV_HIDDEN, STB_WEAK);
 
   S = Config->IsRela ? "__rela_iplt_end" : "__rel_iplt_end";
-  addOptionalRegular(S, InX::RelaIplt, -1, STV_HIDDEN, STB_WEAK);
+  ElfSym::RelaIpltEnd =
+      addOptionalRegular(S, InX::RelaIplt, 0, STV_HIDDEN, STB_WEAK);
 }
 
 template <class ELFT>
-void Writer<ELFT>::forEachRelSec(std::function<void(InputSectionBase &)> Fn) {
+void Writer<ELFT>::forEachRelSec(
+    llvm::function_ref<void(InputSectionBase &)> Fn) {
   // Scan all relocations. Each relocation goes through a series
   // of tests to determine if it needs special treatment, such as
   // creating GOT, PLT, copy relocations, etc.
@@ -869,14 +912,18 @@ void Writer<ELFT>::forEachRelSec(std::function<void(InputSectionBase &)> Fn) {
 // defining these symbols explicitly in the linker script.
 template <class ELFT> void Writer<ELFT>::setReservedSymbolSections() {
   if (ElfSym::GlobalOffsetTable) {
-    // The _GLOBAL_OFFSET_TABLE_ symbol is defined by target convention to
-    // be at some offset from the base of the .got section, usually 0 or the end
-    // of the .got
-    InputSection *GotSection = InX::MipsGot ? cast<InputSection>(InX::MipsGot)
-                                            : cast<InputSection>(InX::Got);
+    // The _GLOBAL_OFFSET_TABLE_ symbol is defined by target convention usually
+    // to the start of the .got or .got.plt section.
+    InputSection *GotSection = InX::GotPlt;
+    if (!Target->GotBaseSymInGotPlt)
+      GotSection = InX::MipsGot ? cast<InputSection>(InX::MipsGot)
+                                : cast<InputSection>(InX::Got);
     ElfSym::GlobalOffsetTable->Section = GotSection;
   }
 
+  if (ElfSym::RelaIpltEnd)
+    ElfSym::RelaIpltEnd->Value = InX::RelaIplt->getSize();
+
   PhdrEntry *Last = nullptr;
   PhdrEntry *LastRO = nullptr;
 
@@ -949,8 +996,7 @@ static int getRankProximityAux(OutputSection *A, OutputSection *B) {
 
 static int getRankProximity(OutputSection *A, BaseCommand *B) {
   if (auto *Sec = dyn_cast<OutputSection>(B))
-    if (Sec->Live)
-      return getRankProximityAux(A, Sec);
+    return getRankProximityAux(A, Sec);
   return -1;
 }
 
@@ -969,11 +1015,9 @@ static int getRankProximity(OutputSection *A, BaseCommand *B) {
 //  rw_sec : { *(rw_sec) }
 // would mean that the RW PT_LOAD would become unaligned.
 static bool shouldSkip(BaseCommand *Cmd) {
-  if (isa<OutputSection>(Cmd))
-    return false;
   if (auto *Assign = dyn_cast<SymbolAssignment>(Cmd))
     return Assign->Name != ".";
-  return true;
+  return false;
 }
 
 // We want to place orphan sections so that they share as much
@@ -996,20 +1040,16 @@ findOrphanPos(std::vector<BaseCommand *>::iterator B,
   int Proximity = getRankProximity(Sec, *I);
   for (; I != E; ++I) {
     auto *CurSec = dyn_cast<OutputSection>(*I);
-    if (!CurSec || !CurSec->Live)
+    if (!CurSec)
       continue;
     if (getRankProximity(Sec, CurSec) != Proximity ||
         Sec->SortRank < CurSec->SortRank)
       break;
   }
 
-  auto IsLiveSection = [](BaseCommand *Cmd) {
-    auto *OS = dyn_cast<OutputSection>(Cmd);
-    return OS && OS->Live;
-  };
-
+  auto IsOutputSec = [](BaseCommand *Cmd) { return isa<OutputSection>(Cmd); };
   auto J = std::find_if(llvm::make_reverse_iterator(I),
-                        llvm::make_reverse_iterator(B), IsLiveSection);
+                        llvm::make_reverse_iterator(B), IsOutputSec);
   I = J.base();
 
   // As a special case, if the orphan section is the last section, put
@@ -1017,7 +1057,7 @@ findOrphanPos(std::vector<BaseCommand *>::iterator B,
   // This matches bfd's behavior and is convenient when the linker script fully
   // specifies the start of the file, but doesn't care about the end (the non
   // alloc sections for example).
-  auto NextSec = std::find_if(I, E, IsLiveSection);
+  auto NextSec = std::find_if(I, E, IsOutputSec);
   if (NextSec == E)
     return E;
 
@@ -1026,32 +1066,172 @@ findOrphanPos(std::vector<BaseCommand *>::iterator B,
   return I;
 }
 
-// If no layout was provided by linker script, we want to apply default
-// sorting for special input sections and handle --symbol-ordering-file.
-template <class ELFT> void Writer<ELFT>::sortInputSections() {
-  assert(!Script->HasSectionsCommand);
+// Builds section order for handling --symbol-ordering-file.
+static DenseMap<const InputSectionBase *, int> buildSectionOrder() {
+  DenseMap<const InputSectionBase *, int> SectionOrder;
+  // Use the rarely used option -call-graph-ordering-file to sort sections.
+  if (!Config->CallGraphProfile.empty())
+    return computeCallGraphProfileOrder();
 
-  // Sort input sections by priority using the list provided
-  // by --symbol-ordering-file.
-  DenseMap<SectionBase *, int> Order = buildSectionOrder();
-  if (!Order.empty())
-    for (BaseCommand *Base : Script->SectionCommands)
-      if (auto *Sec = dyn_cast<OutputSection>(Base))
-        if (Sec->Live)
-          Sec->sort([&](InputSectionBase *S) { return Order.lookup(S); });
+  if (Config->SymbolOrderingFile.empty())
+    return SectionOrder;
+
+  struct SymbolOrderEntry {
+    int Priority;
+    bool Present;
+  };
+
+  // Build a map from symbols to their priorities. Symbols that didn't
+  // appear in the symbol ordering file have the lowest priority 0.
+  // All explicitly mentioned symbols have negative (higher) priorities.
+  DenseMap<StringRef, SymbolOrderEntry> SymbolOrder;
+  int Priority = -Config->SymbolOrderingFile.size();
+  for (StringRef S : Config->SymbolOrderingFile)
+    SymbolOrder.insert({S, {Priority++, false}});
+
+  // Build a map from sections to their priorities.
+  auto AddSym = [&](Symbol &Sym) {
+    auto It = SymbolOrder.find(Sym.getName());
+    if (It == SymbolOrder.end())
+      return;
+    SymbolOrderEntry &Ent = It->second;
+    Ent.Present = true;
+
+    warnUnorderableSymbol(&Sym);
+
+    if (auto *D = dyn_cast<Defined>(&Sym)) {
+      if (auto *Sec = dyn_cast_or_null<InputSectionBase>(D->Section)) {
+        int &Priority = SectionOrder[cast<InputSectionBase>(Sec->Repl)];
+        Priority = std::min(Priority, Ent.Priority);
+      }
+    }
+  };
+  // We want both global and local symbols. We get the global ones from the
+  // symbol table and iterate the object files for the local ones.
+  for (Symbol *Sym : Symtab->getSymbols())
+    if (!Sym->isLazy())
+      AddSym(*Sym);
+  for (InputFile *File : ObjectFiles)
+    for (Symbol *Sym : File->getSymbols())
+      if (Sym->isLocal())
+        AddSym(*Sym);
+
+  if (Config->WarnSymbolOrdering)
+    for (auto OrderEntry : SymbolOrder)
+      if (!OrderEntry.second.Present)
+        warn("symbol ordering file: no such symbol: " + OrderEntry.first);
+
+  return SectionOrder;
+}
+
+// Sorts the sections in ISD according to the provided section order.
+static void
+sortISDBySectionOrder(InputSectionDescription *ISD,
+                      const DenseMap<const InputSectionBase *, int> &Order) {
+  std::vector<InputSection *> UnorderedSections;
+  std::vector<std::pair<InputSection *, int>> OrderedSections;
+  uint64_t UnorderedSize = 0;
+
+  for (InputSection *IS : ISD->Sections) {
+    auto I = Order.find(IS);
+    if (I == Order.end()) {
+      UnorderedSections.push_back(IS);
+      UnorderedSize += IS->getSize();
+      continue;
+    }
+    OrderedSections.push_back({IS, I->second});
+  }
+  llvm::sort(
+      OrderedSections.begin(), OrderedSections.end(),
+      [&](std::pair<InputSection *, int> A, std::pair<InputSection *, int> B) {
+        return A.second < B.second;
+      });
+
+  // Find an insertion point for the ordered section list in the unordered
+  // section list. On targets with limited-range branches, this is the mid-point
+  // of the unordered section list. This decreases the likelihood that a range
+  // extension thunk will be needed to enter or exit the ordered region. If the
+  // ordered section list is a list of hot functions, we can generally expect
+  // the ordered functions to be called more often than the unordered functions,
+  // making it more likely that any particular call will be within range, and
+  // therefore reducing the number of thunks required.
+  //
+  // For example, imagine that you have 8MB of hot code and 32MB of cold code.
+  // If the layout is:
+  //
+  // 8MB hot
+  // 32MB cold
+  //
+  // only the first 8-16MB of the cold code (depending on which hot function it
+  // is actually calling) can call the hot code without a range extension thunk.
+  // However, if we use this layout:
+  //
+  // 16MB cold
+  // 8MB hot
+  // 16MB cold
+  //
+  // both the last 8-16MB of the first block of cold code and the first 8-16MB
+  // of the second block of cold code can call the hot code without a thunk. So
+  // we effectively double the amount of code that could potentially call into
+  // the hot code without a thunk.
+  size_t InsPt = 0;
+  if (Target->ThunkSectionSpacing && !OrderedSections.empty()) {
+    uint64_t UnorderedPos = 0;
+    for (; InsPt != UnorderedSections.size(); ++InsPt) {
+      UnorderedPos += UnorderedSections[InsPt]->getSize();
+      if (UnorderedPos > UnorderedSize / 2)
+        break;
+    }
+  }
+
+  ISD->Sections.clear();
+  for (InputSection *IS : makeArrayRef(UnorderedSections).slice(0, InsPt))
+    ISD->Sections.push_back(IS);
+  for (std::pair<InputSection *, int> P : OrderedSections)
+    ISD->Sections.push_back(P.first);
+  for (InputSection *IS : makeArrayRef(UnorderedSections).slice(InsPt))
+    ISD->Sections.push_back(IS);
+}
+
+static void sortSection(OutputSection *Sec,
+                        const DenseMap<const InputSectionBase *, int> &Order) {
+  StringRef Name = Sec->Name;
 
   // Sort input sections by section name suffixes for
   // __attribute__((init_priority(N))).
-  if (OutputSection *Sec = findSection(".init_array"))
-    Sec->sortInitFini();
-  if (OutputSection *Sec = findSection(".fini_array"))
-    Sec->sortInitFini();
+  if (Name == ".init_array" || Name == ".fini_array") {
+    if (!Script->HasSectionsCommand)
+      Sec->sortInitFini();
+    return;
+  }
 
   // Sort input sections by the special rule for .ctors and .dtors.
-  if (OutputSection *Sec = findSection(".ctors"))
-    Sec->sortCtorsDtors();
-  if (OutputSection *Sec = findSection(".dtors"))
-    Sec->sortCtorsDtors();
+  if (Name == ".ctors" || Name == ".dtors") {
+    if (!Script->HasSectionsCommand)
+      Sec->sortCtorsDtors();
+    return;
+  }
+
+  // Never sort these.
+  if (Name == ".init" || Name == ".fini")
+    return;
+
+  // Sort input sections by priority using the list provided
+  // by --symbol-ordering-file.
+  if (!Order.empty())
+    for (BaseCommand *B : Sec->SectionCommands)
+      if (auto *ISD = dyn_cast<InputSectionDescription>(B))
+        sortISDBySectionOrder(ISD, Order);
+}
+
+// If no layout was provided by linker script, we want to apply default
+// sorting for special input sections. This also handles --symbol-ordering-file.
+template <class ELFT> void Writer<ELFT>::sortInputSections() {
+  // Build the order once since it is expensive.
+  DenseMap<const InputSectionBase *, int> Order = buildSectionOrder();
+  for (BaseCommand *Base : Script->SectionCommands)
+    if (auto *Sec = dyn_cast<OutputSection>(Base))
+      sortSection(Sec, Order);
 }
 
 template <class ELFT> void Writer<ELFT>::sortSections() {
@@ -1062,22 +1242,29 @@ template <class ELFT> void Writer<ELFT>::sortSections() {
   if (Config->Relocatable)
     return;
 
-  for (BaseCommand *Base : Script->SectionCommands)
-    if (auto *Sec = dyn_cast<OutputSection>(Base))
-      Sec->SortRank = getSectionRank(Sec);
+  sortInputSections();
 
-  if (!Script->HasSectionsCommand) {
-    sortInputSections();
+  for (BaseCommand *Base : Script->SectionCommands) {
+    auto *OS = dyn_cast<OutputSection>(Base);
+    if (!OS)
+      continue;
+    OS->SortRank = getSectionRank(OS);
+
+    // We want to assign rude approximation values to OutSecOff fields
+    // to know the relative order of the input sections. We use it for
+    // sorting SHF_LINK_ORDER sections. See resolveShfLinkOrder().
+    uint64_t I = 0;
+    for (InputSection *Sec : getInputSections(OS))
+      Sec->OutSecOff = I++;
+  }
 
+  if (!Script->HasSectionsCommand) {
     // We know that all the OutputSections are contiguous in this case.
-    auto E = Script->SectionCommands.end();
-    auto I = Script->SectionCommands.begin();
     auto IsSection = [](BaseCommand *Base) { return isa<OutputSection>(Base); };
-    I = std::find_if(I, E, IsSection);
-    E = std::find_if(llvm::make_reverse_iterator(E),
-                     llvm::make_reverse_iterator(I), IsSection)
-            .base();
-    std::stable_sort(I, E, compareSections);
+    std::stable_sort(
+        llvm::find_if(Script->SectionCommands, IsSection),
+        llvm::find_if(llvm::reverse(Script->SectionCommands), IsSection).base(),
+        compareSections);
     return;
   }
 
@@ -1108,7 +1295,7 @@ template <class ELFT> void Writer<ELFT>::sortSections() {
   // The way we define an order then is:
   // *  Sort only the orphan sections. They are in the end right now.
   // *  Move each orphan section to its preferred position. We try
-  //    to put each section in the last position where it it can share
+  //    to put each section in the last position where it can share
   //    a PT_LOAD.
   //
   // There is some ambiguity as to where exactly a new entry should be
@@ -1124,7 +1311,7 @@ template <class ELFT> void Writer<ELFT>::sortSections() {
   auto E = Script->SectionCommands.end();
   auto NonScriptI = std::find_if(I, E, [](BaseCommand *Base) {
     if (auto *Sec = dyn_cast<OutputSection>(Base))
-      return Sec->Live && Sec->SectionIndex == INT_MAX;
+      return Sec->SectionIndex == UINT32_MAX;
     return false;
   });
 
@@ -1199,8 +1386,7 @@ static bool isDuplicateArmExidxSec(InputSection *Prev, InputSection *Cur) {
   };
 
   // Get the last table Entry from the previous .ARM.exidx section.
-  const ExidxEntry &PrevEntry = *reinterpret_cast<const ExidxEntry *>(
-      Prev->Data.data() + Prev->getSize() - sizeof(ExidxEntry));
+  const ExidxEntry &PrevEntry = Prev->getDataAs<ExidxEntry>().back();
   if (IsExtabRef(PrevEntry.Unwind))
     return false;
 
@@ -1212,14 +1398,7 @@ static bool isDuplicateArmExidxSec(InputSection *Prev, InputSection *Cur) {
   // consecutive identical entries are rare and the effort to check that they
   // are identical is high.
 
-  if (isa<SyntheticSection>(Cur))
-    // Exidx sentinel section has implicit EXIDX_CANTUNWIND;
-    return PrevEntry.Unwind == 0x1;
-
-  ArrayRef<const ExidxEntry> Entries(
-      reinterpret_cast<const ExidxEntry *>(Cur->Data.data()),
-      Cur->getSize() / sizeof(ExidxEntry));
-  for (const ExidxEntry &Entry : Entries)
+  for (const ExidxEntry Entry : Cur->getDataAs<ExidxEntry>())
     if (IsExtabRef(Entry.Unwind) || Entry.Unwind != PrevEntry.Unwind)
       return false;
   // All table entries in this .ARM.exidx Section can be merged into the
@@ -1249,13 +1428,12 @@ template <class ELFT> void Writer<ELFT>::resolveShfLinkOrder() {
     if (!Config->Relocatable && Config->EMachine == EM_ARM &&
         Sec->Type == SHT_ARM_EXIDX) {
 
-      if (!Sections.empty() && isa<ARMExidxSentinelSection>(Sections.back())) {
+      if (auto *Sentinel = dyn_cast<ARMExidxSentinelSection>(Sections.back())) {
         assert(Sections.size() >= 2 &&
                "We should create a sentinel section only if there are "
                "alive regular exidx sections.");
         // The last executable section is required to fill the sentinel.
         // Remember it here so that we don't have to find it again.
-        auto *Sentinel = cast<ARMExidxSentinelSection>(Sections.back());
         Sentinel->Highest = Sections[Sections.size() - 2]->getLinkOrderDep();
       }
 
@@ -1266,16 +1444,13 @@ template <class ELFT> void Writer<ELFT>::resolveShfLinkOrder() {
         // previous one. This does not require any rewriting of InputSection
         // contents but misses opportunities for fine grained deduplication
         // where only a subset of the InputSection contents can be merged.
-        int Cur = 1;
-        int Prev = 0;
+        size_t Prev = 0;
         // The last one is a sentinel entry which should not be removed.
-        int N = Sections.size() - 1;
-        while (Cur < N) {
-          if (isDuplicateArmExidxSec(Sections[Prev], Sections[Cur]))
-            Sections[Cur] = nullptr;
+        for (size_t I = 1; I < Sections.size() - 1; ++I) {
+          if (isDuplicateArmExidxSec(Sections[Prev], Sections[I]))
+            Sections[I] = nullptr;
           else
-            Prev = Cur;
-          ++Cur;
+            Prev = I;
         }
       }
     }
@@ -1286,14 +1461,12 @@ template <class ELFT> void Writer<ELFT>::resolveShfLinkOrder() {
     // Remove the Sections we marked as duplicate earlier.
     for (BaseCommand *Base : Sec->SectionCommands)
       if (auto *ISD = dyn_cast<InputSectionDescription>(Base))
-        ISD->Sections.erase(
-            std::remove(ISD->Sections.begin(), ISD->Sections.end(), nullptr),
-            ISD->Sections.end());
+        llvm::erase_if(ISD->Sections, [](InputSection *IS) { return !IS; });
   }
 }
 
 static void applySynthetic(const std::vector<SyntheticSection *> &Sections,
-                           std::function<void(SyntheticSection *)> Fn) {
+                           llvm::function_ref<void(SyntheticSection *)> Fn) {
   for (SyntheticSection *SS : Sections)
     if (SS && SS->getParent() && !SS->empty())
       Fn(SS);
@@ -1320,27 +1493,15 @@ static void removeUnusedSyntheticSections() {
     if (!SS)
       return;
     OutputSection *OS = SS->getParent();
-    if (!SS->empty() || !OS)
+    if (!OS || !SS->empty())
       continue;
 
-    std::vector<BaseCommand *>::iterator Empty = OS->SectionCommands.end();
-    for (auto I = OS->SectionCommands.begin(), E = OS->SectionCommands.end();
-         I != E; ++I) {
-      BaseCommand *B = *I;
-      if (auto *ISD = dyn_cast<InputSectionDescription>(B)) {
+    // If we reach here, then SS is an unused synthetic section and we want to
+    // remove it from corresponding input section description of output section.
+    for (BaseCommand *B : OS->SectionCommands)
+      if (auto *ISD = dyn_cast<InputSectionDescription>(B))
         llvm::erase_if(ISD->Sections,
                        [=](InputSection *IS) { return IS == SS; });
-        if (ISD->Sections.empty())
-          Empty = I;
-      }
-    }
-    if (Empty != OS->SectionCommands.end())
-      OS->SectionCommands.erase(Empty);
-
-    // If there are no other sections in the output section, remove it from the
-    // output.
-    if (OS->SectionCommands.empty())
-      OS->Live = false;
   }
 }
 
@@ -1432,9 +1593,9 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
 
     if (InX::DynSymTab && Sym->includeInDynsym()) {
       InX::DynSymTab->addSymbol(Sym);
-      if (auto *SS = dyn_cast<SharedSymbol>(Sym))
-        if (cast<SharedFile<ELFT>>(Sym->File)->IsNeeded)
-          In<ELFT>::VerNeed->addSymbol(SS);
+      if (auto *File = dyn_cast_or_null<SharedFile<ELFT>>(Sym->File))
+        if (File->IsNeeded && !Sym->isUndefined())
+          In<ELFT>::VerNeed->addSymbol(Sym);
     }
   }
 
@@ -1442,10 +1603,12 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
   if (errorCount())
     return;
 
+  if (InX::MipsGot)
+    InX::MipsGot->build<ELFT>();
+
   removeUnusedSyntheticSections();
 
   sortSections();
-  Script->removeEmptyCommands();
 
   // Now that we have the final list, create a list of all the
   // OutputSections for convenience.
@@ -1453,6 +1616,15 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
     if (auto *Sec = dyn_cast<OutputSection>(Base))
       OutputSections.push_back(Sec);
 
+  // Ensure data sections are not mixed with executable sections when
+  // -execute-only is used.
+  if (Config->ExecuteOnly)
+    for (OutputSection *OS : OutputSections)
+      if (OS->Flags & SHF_EXECINSTR)
+        for (InputSection *IS : getInputSections(OS))
+          if (!(IS->Flags & SHF_EXECINSTR))
+            error("-execute-only does not support intermingling data and code");
+
   // Prefer command line supplied address over other constraints.
   for (OutputSection *Sec : OutputSections) {
     auto I = Config->SectionStartMap.find(Sec->Name);
@@ -1461,7 +1633,7 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
   }
 
   // This is a bit of a hack. A value of 0 means undef, so we set it
-  // to 1 t make __ehdr_start defined. The section number is not
+  // to 1 to make __ehdr_start defined. The section number is not
   // particularly relevant.
   Out::ElfHeader->SectionIndex = 1;
 
@@ -1487,12 +1659,13 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
   // Dynamic section must be the last one in this list and dynamic
   // symbol table section (DynSymTab) must be the first one.
   applySynthetic(
-      {InX::DynSymTab,   InX::Bss,          InX::BssRelRo, InX::GnuHashTab,
-       InX::HashTab,     InX::SymTab,       InX::ShStrTab, InX::StrTab,
-       In<ELFT>::VerDef, InX::DynStrTab,    InX::Got,      InX::MipsGot,
-       InX::IgotPlt,     InX::GotPlt,       InX::RelaDyn,  InX::RelaIplt,
-       InX::RelaPlt,     InX::Plt,          InX::Iplt,     InX::EhFrameHdr,
-       In<ELFT>::VerSym, In<ELFT>::VerNeed, InX::Dynamic},
+      {InX::DynSymTab, InX::Bss,         InX::BssRelRo,    InX::GnuHashTab,
+       InX::HashTab,   InX::SymTab,      InX::SymTabShndx, InX::ShStrTab,
+       InX::StrTab,    In<ELFT>::VerDef, InX::DynStrTab,   InX::Got,
+       InX::MipsGot,   InX::IgotPlt,     InX::GotPlt,      InX::RelaDyn,
+       InX::RelrDyn,   InX::RelaIplt,    InX::RelaPlt,     InX::Plt,
+       InX::Iplt,      InX::EhFrameHdr,  In<ELFT>::VerSym, In<ELFT>::VerNeed,
+       InX::Dynamic},
       [](SyntheticSection *SS) { SS->finalizeContents(); });
 
   if (!Script->HasSectionsCommand && !Config->Relocatable)
@@ -1504,10 +1677,11 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
 
   // Some architectures need to generate content that depends on the address
   // of InputSections. For example some architectures use small displacements
-  // for jump instructions that is is the linker's responsibility for creating
+  // for jump instructions that is the linker's responsibility for creating
   // range extension thunks for. As the generation of the content may also
   // alter InputSection addresses we must converge to a fixed point.
-  if (Target->NeedsThunks || Config->AndroidPackDynRelocs) {
+  if (Target->NeedsThunks || Config->AndroidPackDynRelocs ||
+      Config->RelrPackDynRelocs) {
     ThunkCreator TC;
     AArch64Err843419Patcher A64P;
     bool Changed;
@@ -1524,34 +1698,48 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
       if (InX::MipsGot)
         InX::MipsGot->updateAllocSize();
       Changed |= InX::RelaDyn->updateAllocSize();
+      if (InX::RelrDyn)
+        Changed |= InX::RelrDyn->updateAllocSize();
     } while (Changed);
   }
 
+  // createThunks may have added local symbols to the static symbol table
+  applySynthetic({InX::SymTab},
+                 [](SyntheticSection *SS) { SS->postThunkContents(); });
+
   // Fill other section headers. The dynamic table is finalized
   // at the end because some tags like RELSZ depend on result
   // of finalizing other sections.
   for (OutputSection *Sec : OutputSections)
     Sec->finalize<ELFT>();
-
-  // createThunks may have added local symbols to the static symbol table
-  applySynthetic({InX::SymTab},
-                 [](SyntheticSection *SS) { SS->postThunkContents(); });
 }
 
 // The linker is expected to define SECNAME_start and SECNAME_end
 // symbols for a few sections. This function defines them.
 template <class ELFT> void Writer<ELFT>::addStartEndSymbols() {
-  auto Define = [&](StringRef Start, StringRef End, OutputSection *OS) {
-    // These symbols resolve to the image base if the section does not exist.
-    // A special value -1 indicates end of the section.
+  // If a section does not exist, there's ambiguity as to how we
+  // define _start and _end symbols for an init/fini section. Since
+  // the loader assume that the symbols are always defined, we need to
+  // always define them. But what value? The loader iterates over all
+  // pointers between _start and _end to run global ctors/dtors, so if
+  // the section is empty, their symbol values don't actually matter
+  // as long as _start and _end point to the same location.
+  //
+  // That said, we don't want to set the symbols to 0 (which is
+  // probably the simplest value) because that could cause some
+  // program to fail to link due to relocation overflow, if their
+  // program text is above 2 GiB. We use the address of the .text
+  // section instead to prevent that failure.
+  OutputSection *Default = findSection(".text");
+  if (!Default)
+    Default = Out::ElfHeader;
+  auto Define = [=](StringRef Start, StringRef End, OutputSection *OS) {
     if (OS) {
       addOptionalRegular(Start, OS, 0);
       addOptionalRegular(End, OS, -1);
     } else {
-      if (Config->Pic)
-        OS = Out::ElfHeader;
-      addOptionalRegular(Start, OS, 0);
-      addOptionalRegular(End, OS, 0);
+      addOptionalRegular(Start, Default, 0);
+      addOptionalRegular(End, Default, 0);
     }
   };
 
@@ -1573,12 +1761,12 @@ void Writer<ELFT>::addStartStopSymbols(OutputSection *Sec) {
   StringRef S = Sec->Name;
   if (!isValidCIdentifier(S))
     return;
-  addOptionalRegular(Saver.save("__start_" + S), Sec, 0, STV_DEFAULT);
-  addOptionalRegular(Saver.save("__stop_" + S), Sec, -1, STV_DEFAULT);
+  addOptionalRegular(Saver.save("__start_" + S), Sec, 0, STV_PROTECTED);
+  addOptionalRegular(Saver.save("__stop_" + S), Sec, -1, STV_PROTECTED);
 }
 
 static bool needsPtLoad(OutputSection *Sec) {
-  if (!(Sec->Flags & SHF_ALLOC))
+  if (!(Sec->Flags & SHF_ALLOC) || Sec->Noload)
     return false;
 
   // Don't allocate VA space for TLS NOBITS sections. The PT_TLS PHDR is
@@ -1596,6 +1784,8 @@ static bool needsPtLoad(OutputSection *Sec) {
 static uint64_t computeFlags(uint64_t Flags) {
   if (Config->Omagic)
     return PF_R | PF_W | PF_X;
+  if (Config->ExecuteOnly && (Flags & PF_X))
+    return Flags & ~PF_R;
   if (Config->SingleRoRx && !(Flags & PF_W))
     return Flags | PF_X;
   return Flags;
@@ -1634,10 +1824,14 @@ template <class ELFT> std::vector<PhdrEntry *> Writer<ELFT>::createPhdrs() {
     // Segments are contiguous memory regions that has the same attributes
     // (e.g. executable or writable). There is one phdr for each segment.
     // Therefore, we need to create a new phdr when the next section has
-    // different flags or is loaded at a discontiguous address using AT linker
-    // script command.
+    // different flags or is loaded at a discontiguous address or memory
+    // region using AT or AT> linker script command, respectively. At the same
+    // time, we don't want to create a separate load segment for the headers,
+    // even if the first output section has an AT or AT> attribute.
     uint64_t NewFlags = computeFlags(Sec->getPhdrFlags());
-    if ((Sec->LMAExpr && Load->ASectionHasLMA) ||
+    if (((Sec->LMAExpr ||
+          (Sec->LMARegion && (Sec->LMARegion != Load->FirstSec->LMARegion))) &&
+         Load->LastSec != Out::ProgramHeaders) ||
         Sec->MemRegion != Load->FirstSec->MemRegion || Flags != NewFlags) {
 
       Load = AddHdr(PT_LOAD, NewFlags);
@@ -1700,11 +1894,9 @@ template <class ELFT> std::vector<PhdrEntry *> Writer<ELFT>::createPhdrs() {
   // pages for the stack non-executable. If you really want an executable
   // stack, you can pass -z execstack, but that's not recommended for
   // security reasons.
-  unsigned Perm;
+  unsigned Perm = PF_R | PF_W;
   if (Config->ZExecstack)
-    Perm = PF_R | PF_W | PF_X;
-  else
-    Perm = PF_R | PF_W;
+    Perm |= PF_X;
   AddHdr(PT_GNU_STACK, Perm)->p_memsz = Config->ZStackSize;
 
   // PT_OPENBSD_WXNEEDED is a OpenBSD-specific header to mark the executable
@@ -1717,7 +1909,7 @@ template <class ELFT> std::vector<PhdrEntry *> Writer<ELFT>::createPhdrs() {
   // Create one PT_NOTE per a group of contiguous .note sections.
   PhdrEntry *Note = nullptr;
   for (OutputSection *Sec : OutputSections) {
-    if (Sec->Type == SHT_NOTE) {
+    if (Sec->Type == SHT_NOTE && (Sec->Flags & SHF_ALLOC)) {
       if (!Note || Sec->LMAExpr)
         Note = AddHdr(PT_NOTE, PF_R);
       Note->add(Sec);
@@ -1822,6 +2014,12 @@ template <class ELFT> void Writer<ELFT>::assignFileOffsetsBinary() {
   FileSize = alignTo(Off, Config->Wordsize);
 }
 
+static std::string rangeToString(uint64_t Addr, uint64_t Len) {
+  if (Len == 0)
+    return "<empty range at 0x" + utohexstr(Addr) + ">";
+  return "[0x" + utohexstr(Addr) + ", 0x" + utohexstr(Addr + Len - 1) + "]";
+}
+
 // Assign file offsets to output sections.
 template <class ELFT> void Writer<ELFT>::assignFileOffsets() {
   uint64_t Off = 0;
@@ -1846,6 +2044,24 @@ template <class ELFT> void Writer<ELFT>::assignFileOffsets() {
 
   SectionHeaderOff = alignTo(Off, Config->Wordsize);
   FileSize = SectionHeaderOff + (OutputSections.size() + 1) * sizeof(Elf_Shdr);
+
+  // Our logic assumes that sections have rising VA within the same segment.
+  // With use of linker scripts it is possible to violate this rule and get file
+  // offset overlaps or overflows. That should never happen with a valid script
+  // which does not move the location counter backwards and usually scripts do
+  // not do that. Unfortunately, there are apps in the wild, for example, Linux
+  // kernel, which control segment distribution explicitly and move the counter
+  // backwards, so we have to allow doing that to support linking them. We
+  // perform non-critical checks for overlaps in checkSectionOverlap(), but here
+  // we want to prevent file size overflows because it would crash the linker.
+  for (OutputSection *Sec : OutputSections) {
+    if (Sec->Type == SHT_NOBITS)
+      continue;
+    if ((Sec->Offset > FileSize) || (Sec->Offset + Sec->Size > FileSize))
+      error("unable to place section " + Sec->Name + " at file offset " +
+            rangeToString(Sec->Offset, Sec->Offset + Sec->Size) +
+            "; check your linker script for overflows");
+  }
 }
 
 // Finalize the program headers. We call this function after we assign
@@ -1884,6 +2100,97 @@ template <class ELFT> void Writer<ELFT>::setPhdrs() {
   }
 }
 
+// A helper struct for checkSectionOverlap.
+namespace {
+struct SectionOffset {
+  OutputSection *Sec;
+  uint64_t Offset;
+};
+} // namespace
+
+// Check whether sections overlap for a specific address range (file offsets,
+// load and virtual adresses).
+static void checkOverlap(StringRef Name, std::vector<SectionOffset> &Sections,
+                         bool IsVirtualAddr) {
+  llvm::sort(Sections.begin(), Sections.end(),
+             [=](const SectionOffset &A, const SectionOffset &B) {
+               return A.Offset < B.Offset;
+             });
+
+  // Finding overlap is easy given a vector is sorted by start position.
+  // If an element starts before the end of the previous element, they overlap.
+  for (size_t I = 1, End = Sections.size(); I < End; ++I) {
+    SectionOffset A = Sections[I - 1];
+    SectionOffset B = Sections[I];
+    if (B.Offset >= A.Offset + A.Sec->Size)
+      continue;
+
+    // If both sections are in OVERLAY we allow the overlapping of virtual
+    // addresses, because it is what OVERLAY was designed for.
+    if (IsVirtualAddr && A.Sec->InOverlay && B.Sec->InOverlay)
+      continue;
+
+    errorOrWarn("section " + A.Sec->Name + " " + Name +
+                " range overlaps with " + B.Sec->Name + "\n>>> " + A.Sec->Name +
+                " range is " + rangeToString(A.Offset, A.Sec->Size) + "\n>>> " +
+                B.Sec->Name + " range is " +
+                rangeToString(B.Offset, B.Sec->Size));
+  }
+}
+
+// Check for overlapping sections and address overflows.
+//
+// In this function we check that none of the output sections have overlapping
+// file offsets. For SHF_ALLOC sections we also check that the load address
+// ranges and the virtual address ranges don't overlap
+template <class ELFT> void Writer<ELFT>::checkSections() {
+  // First, check that section's VAs fit in available address space for target.
+  for (OutputSection *OS : OutputSections)
+    if ((OS->Addr + OS->Size < OS->Addr) ||
+        (!ELFT::Is64Bits && OS->Addr + OS->Size > UINT32_MAX))
+      errorOrWarn("section " + OS->Name + " at 0x" + utohexstr(OS->Addr) +
+                  " of size 0x" + utohexstr(OS->Size) +
+                  " exceeds available address space");
+
+  // Check for overlapping file offsets. In this case we need to skip any
+  // section marked as SHT_NOBITS. These sections don't actually occupy space in
+  // the file so Sec->Offset + Sec->Size can overlap with others. If --oformat
+  // binary is specified only add SHF_ALLOC sections are added to the output
+  // file so we skip any non-allocated sections in that case.
+  std::vector<SectionOffset> FileOffs;
+  for (OutputSection *Sec : OutputSections)
+    if (0 < Sec->Size && Sec->Type != SHT_NOBITS &&
+        (!Config->OFormatBinary || (Sec->Flags & SHF_ALLOC)))
+      FileOffs.push_back({Sec, Sec->Offset});
+  checkOverlap("file", FileOffs, false);
+
+  // When linking with -r there is no need to check for overlapping virtual/load
+  // addresses since those addresses will only be assigned when the final
+  // executable/shared object is created.
+  if (Config->Relocatable)
+    return;
+
+  // Checking for overlapping virtual and load addresses only needs to take
+  // into account SHF_ALLOC sections since others will not be loaded.
+  // Furthermore, we also need to skip SHF_TLS sections since these will be
+  // mapped to other addresses at runtime and can therefore have overlapping
+  // ranges in the file.
+  std::vector<SectionOffset> VMAs;
+  for (OutputSection *Sec : OutputSections)
+    if (0 < Sec->Size && (Sec->Flags & SHF_ALLOC) && !(Sec->Flags & SHF_TLS))
+      VMAs.push_back({Sec, Sec->Addr});
+  checkOverlap("virtual address", VMAs, true);
+
+  // Finally, check that the load addresses don't overlap. This will usually be
+  // the same as the virtual addresses but can be different when using a linker
+  // script with AT().
+  std::vector<SectionOffset> LMAs;
+  for (OutputSection *Sec : OutputSections)
+    if (0 < Sec->Size && (Sec->Flags & SHF_ALLOC) && !(Sec->Flags & SHF_TLS))
+      LMAs.push_back({Sec, Sec->getLMA()});
+  checkOverlap("load address", LMAs, false);
+}
+
 // The entry point address is chosen in the following ways.
 //
 // 1. the '-e' entry command-line option;
@@ -1925,8 +2232,20 @@ static uint16_t getELFType() {
   return ET_EXEC;
 }
 
+static uint8_t getAbiVersion() {
+  // MIPS non-PIC executable gets ABI version 1.
+  if (Config->EMachine == EM_MIPS && getELFType() == ET_EXEC &&
+      (Config->EFlags & (EF_MIPS_PIC | EF_MIPS_CPIC)) == EF_MIPS_CPIC)
+    return 1;
+  return 0;
+}
+
 template <class ELFT> void Writer<ELFT>::writeHeader() {
   uint8_t *Buf = Buffer->getBufferStart();
+  // For executable segments, the trap instructions are written before writing
+  // the header. Setting Elf header bytes to zero ensures that any unused bytes
+  // in header are zero-cleared, instead of having trap instructions.
+  memset(Buf, 0, sizeof(Elf_Ehdr));
   memcpy(Buf, "\177ELF", 4);
 
   // Write the ELF header.
@@ -1935,6 +2254,7 @@ template <class ELFT> void Writer<ELFT>::writeHeader() {
   EHdr->e_ident[EI_DATA] = Config->IsLE ? ELFDATA2LSB : ELFDATA2MSB;
   EHdr->e_ident[EI_VERSION] = EV_CURRENT;
   EHdr->e_ident[EI_OSABI] = Config->OSABI;
+  EHdr->e_ident[EI_ABIVERSION] = getAbiVersion();
   EHdr->e_type = getELFType();
   EHdr->e_machine = Config->EMachine;
   EHdr->e_version = EV_CURRENT;
@@ -1944,8 +2264,6 @@ template <class ELFT> void Writer<ELFT>::writeHeader() {
   EHdr->e_ehsize = sizeof(Elf_Ehdr);
   EHdr->e_phnum = Phdrs.size();
   EHdr->e_shentsize = sizeof(Elf_Shdr);
-  EHdr->e_shnum = OutputSections.size() + 1;
-  EHdr->e_shstrndx = InX::ShStrTab->getParent()->SectionIndex;
 
   if (!Config->Relocatable) {
     EHdr->e_phoff = sizeof(Elf_Ehdr);
@@ -1966,8 +2284,30 @@ template <class ELFT> void Writer<ELFT>::writeHeader() {
     ++HBuf;
   }
 
-  // Write the section header table. Note that the first table entry is null.
+  // Write the section header table.
+  //
+  // The ELF header can only store numbers up to SHN_LORESERVE in the e_shnum
+  // and e_shstrndx fields. When the value of one of these fields exceeds
+  // SHN_LORESERVE ELF requires us to put sentinel values in the ELF header and
+  // use fields in the section header at index 0 to store
+  // the value. The sentinel values and fields are:
+  // e_shnum = 0, SHdrs[0].sh_size = number of sections.
+  // e_shstrndx = SHN_XINDEX, SHdrs[0].sh_link = .shstrtab section index.
   auto *SHdrs = reinterpret_cast<Elf_Shdr *>(Buf + EHdr->e_shoff);
+  size_t Num = OutputSections.size() + 1;
+  if (Num >= SHN_LORESERVE)
+    SHdrs->sh_size = Num;
+  else
+    EHdr->e_shnum = Num;
+
+  uint32_t StrTabIndex = InX::ShStrTab->getParent()->SectionIndex;
+  if (StrTabIndex >= SHN_LORESERVE) {
+    SHdrs->sh_link = StrTabIndex;
+    EHdr->e_shstrndx = SHN_XINDEX;
+  } else {
+    EHdr->e_shstrndx = StrTabIndex;
+  }
+
   for (OutputSection *Sec : OutputSections)
     Sec->writeHeaderTo<ELFT>(++SHdrs);
 }
@@ -2038,14 +2378,6 @@ template <class ELFT> void Writer<ELFT>::writeTrapInstr() {
 template <class ELFT> void Writer<ELFT>::writeSections() {
   uint8_t *Buf = Buffer->getBufferStart();
 
-  // PPC64 needs to process relocations in the .opd section
-  // before processing relocations in code-containing sections.
-  if (auto *OpdCmd = findSection(".opd")) {
-    Out::Opd = OpdCmd;
-    Out::OpdBuf = Buf + Out::Opd->Offset;
-    OpdCmd->template writeTo<ELFT>(Buf + Out::Opd->Offset);
-  }
-
   OutputSection *EhFrameHdr = nullptr;
   if (InX::EhFrameHdr && !InX::EhFrameHdr->empty())
     EhFrameHdr = InX::EhFrameHdr->getParent();
@@ -2058,8 +2390,7 @@ template <class ELFT> void Writer<ELFT>::writeSections() {
       Sec->writeTo<ELFT>(Buf + Sec->Offset);
 
   for (OutputSection *Sec : OutputSections)
-    if (Sec != Out::Opd && Sec != EhFrameHdr && Sec->Type != SHT_REL &&
-        Sec->Type != SHT_RELA)
+    if (Sec != EhFrameHdr && Sec->Type != SHT_REL && Sec->Type != SHT_RELA)
       Sec->writeTo<ELFT>(Buf + Sec->Offset);
 
   // The .eh_frame_hdr depends on .eh_frame section contents, therefore
diff --git a/gnu/llvm/tools/lld/docs/ld.lld.1 b/gnu/llvm/tools/lld/docs/ld.lld.1
index 64e3e2dc624..98fc3a34bd1 100644
--- a/gnu/llvm/tools/lld/docs/ld.lld.1
+++ b/gnu/llvm/tools/lld/docs/ld.lld.1
@@ -3,7 +3,7 @@
 .\"
 .\" This man page documents only lld's ELF linking support, obtained originally
 .\" from FreeBSD.
-.Dd February 9, 2018
+.Dd September 14, 2018
 .Dt LD.LLD 1
 .Os
 .Sh NAME
@@ -30,22 +30,24 @@ These options are available:
 .It Fl -allow-multiple-definition
 Do not error if a symbol is defined multiple times.
 The first definition will be used.
+.It Fl -apply-dynamic-relocs
+Apply link-time values for dynamic relocations.
 .It Fl -as-needed
 Only set
 .Dv DT_NEEDED
 for shared libraries if used.
-.It Fl -auxiliary Ar value
+.It Fl -auxiliary Ns = Ns Ar value
 Set the
 .Dv DT_AUXILIARY
 field to the specified name.
-.It Fl -Bdynamic
+.It Fl -Bdynamic , Fl -dy
 Link against shared libraries.
-.It Fl -Bstatic
+.It Fl -Bstatic , Fl -static , Fl -dn
 Do not link against shared libraries.
-.It Fl -Bsymbolic-functions
-Bind defined function symbols locally.
 .It Fl -Bsymbolic
 Bind defined symbols locally.
+.It Fl -Bsymbolic-functions
+Bind defined function symbols locally.
 .It Fl -build-id Ns = Ns Ar value
 Generate a build ID note.
 .Ar value
@@ -93,7 +95,9 @@ may be
 .Cm none
 or
 .Cm zlib .
-.It Fl -define-common
+.It Fl -cref
+Output cross reference table.
+.It Fl -define-common , Fl d
 Assign space to common symbols.
 .It Fl -defsym Ns = Ns Ar symbol Ns = Ns Ar expression
 Define a symbol alias.
@@ -107,13 +111,13 @@ or
 Demangle symbol names.
 .It Fl -disable-new-dtags
 Disable new dynamic tags.
-.It Fl -discard-all
+.It Fl -discard-all , Fl x
 Delete all local symbols.
-.It Fl -discard-locals
+.It Fl -discard-locals , Fl X
 Delete temporary local symbols.
 .It Fl -discard-none
 Keep all symbols in the symbol table.
-.It Fl -dynamic-linker Ar value
+.It Fl -dynamic-linker Ns = Ns Ar value
 Specify the dynamic linker to be used for a dynamically linked executable.
 This is recorded in an ELF segment of type
 .Dv PT_INTERP .
@@ -126,7 +130,7 @@ Request creation of
 section and
 .Dv PT_GNU_EH_FRAME
 segment header.
-.It Fl -emit-relocs
+.It Fl -emit-relocs , Fl q
 Generate relocations in the output.
 .It Fl -enable-new-dtags
 Enable new dynamic tags.
@@ -142,21 +146,21 @@ A value of zero indicates that there is no limit.
 Report unresolved symbols as errors.
 .It Fl -exclude-libs Ns = Ns Ar value
 Exclude static libraries from automatic export.
+.It Fl -export-dynamic , Fl E
+Put symbols in the dynamic symbol table.
 .It Fl -export-dynamic-symbol Ns = Ns Ar symbol
 Include
 .Ar symbol
 in the dynamic symbol table.
-.It Fl -export-dynamic
-Put symbols in the dynamic symbol table.
 .It Fl -fatal-warnings
 Treat warnings as errors.
-.It Fl -filter Ns = Ns Ar value
+.It Fl -filter Ns = Ns Ar value , Fl F Ar value
 Set the
 .Dv DT_FILTER
 field to the specified value.
 .It Fl -fini Ns = Ns Ar symbol
 Specify a finalizer function.
-.It Fl -format Ns = Ns Ar input-format
+.It Fl -format Ns = Ns Ar input-format , Fl b Ar input-format
 Specify the format of the inputs following this option.
 .Ar input-format
 may be one of
@@ -187,6 +191,8 @@ is the default.
 Print a help message.
 .It Fl -icf Ns = Ns Cm all
 Enable identical code folding.
+.It Fl -icf Ns = Ns Cm safe
+Enable safe identical code folding.
 .It Fl -icf Ns = Ns Cm none
 Disable identical code folding.
 .It Fl -image-base Ns = Ns Ar value
@@ -194,25 +200,29 @@ Set the base address to
 .Ar value .
 .It Fl -init Ns = Ns Ar symbol
 Specify an initializer function.
+.It Fl -keep-unique Ns = Ns Ar symbol
+Do not fold
+.Ar symbol
+during ICF.
+.It Fl l Ar libName, Fl -library Ns = Ns Ar libName
+Root name of library to use.
+.It Fl L Ar dir , Fl -library-path Ns = Ns Ar dir
+Add a directory to the library search path.
 .It Fl -lto-aa-pipeline Ns = Ns Ar value
 AA pipeline to run during LTO.
 Used in conjunction with
 .Fl -lto-newpm-passes .
 .It Fl -lto-newpm-passes Ns = Ns Ar value
 Passes to run during LTO.
-.It Fl -lto-O Ar opt-level
+.It Fl -lto-O Ns Ar opt-level
 Optimization level for LTO.
 .It Fl -lto-partitions Ns = Ns Ar value
 Number of LTO codegen partitions.
-.It Fl L Ar dir
-Add a directory to the library search path.
-.It Fl l Ar libName
-Root name of library to use.
-.It Fl -Map Ns = Ns Ar file
-Print a link map to
-.Ar file .
 .It Fl m Ar value
 Set target emulation.
+.It Fl -Map Ns = Ns Ar file , Fl M Ar file
+Print a link map to
+.Ar file .
 .It Fl -no-as-needed
 Always set
 .Dv DT_NEEDED
@@ -241,26 +251,18 @@ Report version scripts that refer undefined symbols.
 Report unresolved symbols even if the linker is creating a shared library.
 .It Fl -no-whole-archive
 Restores the default behavior of loading archive members.
-.It Fl -noinhibit-exec
-Retain the executable output file whenever it is still usable.
 .It Fl -no-pie
 Do not create a position independent executable.
+.It Fl -noinhibit-exec
+Retain the executable output file whenever it is still usable.
 .It Fl -nostdlib
 Only search directories specified on the command line.
-.It Fl -oformat Ar format
-Specify the format for the output object file.
-The only supported
-.Ar format
-is
-.Cm binary ,
-which produces output with no ELF header.
-.It Fl -omagic
-Set the text and data sections to be readable and writable.
-.It Fl -opt-remarks-filename Ar file
-Write optimization remarks in YAML format to
-.Ar file .
-.It Fl -opt-remarks-with-hotness
-Include hotness information in the optimization remarks file.
+.It Fl o Ar path
+Write the output executable, library, or object to
+.Ar path .
+If not specified,
+.Dv a.out
+is used as a default.
 .It Fl O Ns Ar value
 Optimize output file size.
 .Ar value
@@ -277,25 +279,42 @@ Enable string tail merging.
 .Pp
 .Fl O Ns Cm 1
 is the default.
-.It Fl o Ar path
-Write the output executable, library, or object to
-.Ar path .
-If not specified,
-.Dv a.out
-is used as a default.
+.It Fl -oformat Ns = Ns Ar format
+Specify the format for the output object file.
+The only supported
+.Ar format
+is
+.Cm binary ,
+which produces output with no ELF header.
+.It Fl -omagic , Fl N
+Set the text and data sections to be readable and writable.
+.It Fl -opt-remarks-filename Ar file
+Write optimization remarks in YAML format to
+.Ar file .
+.It Fl -opt-remarks-with-hotness
+Include hotness information in the optimization remarks file.
 .It Fl -pie
 Create a position independent executable.
 .It Fl -print-gc-sections
 List removed unused sections.
 .It Fl -print-map
 Print a link map to the standard output.
-.It Fl -relocatable
+.It Fl -push-state
+Save the current state of
+.Fl -as-needed ,
+.Fl -static ,
+and
+.Fl -while-archive.
+.It Fl -pop-state
+Undo the effect of
+.Fl -push-state.
+.It Fl -relocatable , Fl r
 Create relocatable object file.
 .It Fl -reproduce Ns = Ns Ar value
 Dump linker invocation and input files for debugging.
 .It Fl -retain-symbols-file Ns = Ns Ar file
 Retain only the symbols listed in the file.
-.It Fl -rpath Ns = Ns Ar value
+.It Fl -rpath Ns = Ns Ar value , Fl R Ar value
 Add a
 .Dv DT_RUNPATH
 to the output.
@@ -305,14 +324,14 @@ The supported values are
 .Cm windows
 and
 .Cm posix .
-.It Fl -script Ns = Ns Ar file
+.It Fl -script Ns = Ns Ar file , Fl T Ar file
 Read linker script from
 .Ar file .
-.It Fl -section-start Ar section Ns = Ns Ar address
+.It Fl -section-start Ns = Ns Ar section Ns = Ns Ar address
 Set address of section.
-.It Fl -shared
+.It Fl -shared , Fl -Bsharable
 Build a shared object.
-.It Fl -soname Ns = Ns Ar value
+.It Fl -soname Ns = Ns Ar value , Fl h Ar value
 Set
 .Dv DT_SONAME
 to
@@ -322,11 +341,11 @@ Specifies sections sorting rule when linkerscript is used.
 .It Fl -start-lib
 Start a grouping of objects that should be treated as if they were together
 in an archive.
-.It Fl -strip-all
+.It Fl -strip-all , Fl s
 Strip all symbols.
-.It Fl -strip-debug
+.It Fl -strip-debug , Fl S
 Strip debugging information.
-.It Fl -symbol-ordering-file Ar file
+.It Fl -symbol-ordering-file Ns = Ns Ar file
 Lay out sections in the order specified by
 .Ar file .
 .It Fl -sysroot Ns = Ns Ar value
@@ -365,42 +384,46 @@ Same as
 with
 .Li .data
 as the sectionname.
+.It Fl -Ttext Ns = Ns Ar value
+Same as
+.Fl -section-start
+with
+.Li .text
+as the sectionname.
 .It Fl -thinlto-cache-dir Ns = Ns Ar value
 Path to ThinLTO cached object file directory.
-.It Fl -thinlto-cache-policy Ar value
+.It Fl -thinlto-cache-policy Ns = Ns Ar value
 Pruning policy for the ThinLTO cache.
 .It Fl -thinlto-jobs Ns = Ns Ar value
 Number of ThinLTO jobs.
 .It Fl -threads
 Run the linker multi-threaded.
 This option is enabled by default.
-.It Fl -trace-symbol Ns = Ns Ar symbol
-Trace references to
-.Ar symbol .
 .It Fl -trace
 Print the names of the input files.
-.It Fl -Ttext Ns = Ns Ar value
-Same as
-.Fl -section-start
-with
-.Li .text
-as the sectionname.
-.It Fl -undefined Ns = Ns Ar symbol
+.It Fl -trace-symbol Ns = Ns Ar symbol , Fl y Ar symbol
+Trace references to
+.Ar symbol .
+.It Fl -undefined Ns = Ns Ar symbol , Fl u Ar symbol
 Force
 .Ar symbol
 to be an undefined symbol during linking.
 .It Fl -unresolved-symbols Ns = Ns Ar value
 Determine how to handle unresolved symbols.
+.It Fl v
+Display the version number and proceed with linking if object files are
+specified.
+.It Fl V , Fl -version
+Display the version number and exit.
 .It Fl -verbose
 Verbose mode.
 .It Fl -version-script Ns = Ns Ar file
 Read version script from
 .Ar file .
-.It Fl V , Fl -version
-Display the version number and exit.
-.It Fl v
-Display the version number and proceed with linking if object files are
-specified.
+.It Fl -warn-backrefs
+Warn about reverse or cyclic dependencies to or between static archives.
+This can be used to ensure linker invocation remains compatible with
+traditional Unix-like linkers.
 .It Fl -warn-common
 Warn about duplicate common symbols.
 .It Fl -warn-unresolved-symbols
@@ -417,6 +440,16 @@ Make the main stack executable.
 Stack permissions are recorded in the
 .Dv PT_GNU_STACK
 segment.
+.It Cm initfirst
+Sets the
+.Dv DF_1_INITFIRST
+flag to indicate the module should be initialized first.
+.It Cm interpose
+Set the
+.Dv DF_1_INTERPOSE
+flag to indicate to the runtime linker that the object is an interposer.
+During symbol resolution interposers are searched after the application
+but before other dependencies.
 .It Cm muldefs
 Do not error if a symbol is defined multiple times.
 The first definition will be used.
@@ -525,3 +558,8 @@ may produce different results compared to traditional linkers.
 In practice, large bodies of third party software have been linked with
 .Nm
 without material issues.
+.Pp
+The
+.Fl -warn-backrefs
+option may be used to identify a linker invocation that may be incompatible
+with traditional Unix-like linker behavior.
diff --git a/gnu/llvm/tools/lld/tools/lld/lld.cpp b/gnu/llvm/tools/lld/tools/lld/lld.cpp
index 01aae99e757..e84a94cc3f5 100644
--- a/gnu/llvm/tools/lld/tools/lld/lld.cpp
+++ b/gnu/llvm/tools/lld/tools/lld/lld.cpp
@@ -7,12 +7,22 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This is the entry point to the lld driver. This is a thin wrapper which
-// dispatches to the given platform specific driver.
+// This file contains the main function of the lld executable. The main
+// function is a thin wrapper which dispatches to the platform specific
+// driver.
 //
-// If there is -flavor option, it is dispatched according to the arguments.
-// If the flavor parameter is not present, then it is dispatched according
-// to argv[0].
+// lld is a single executable that contains four different linkers for ELF,
+// COFF, WebAssembly and Mach-O. The main function dispatches according to
+// argv[0] (i.e. command name). The most common name for each target is shown
+// below:
+//
+//  - ld.lld:    ELF (Unix)
+//  - ld64:      Mach-O (macOS)
+//  - lld-link:  COFF (Windows)
+//  - ld-wasm:   WebAssembly
+//
+// lld can be invoked as "lld" along with "-flavor" option. This is for
+// backward compatibility and not recommended.
 //
 //===----------------------------------------------------------------------===//
 
@@ -20,10 +30,9 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Twine.h"
-#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/Path.h"
-#include "llvm/Support/PrettyStackTrace.h"
-#include "llvm/Support/Signals.h"
+#include <cstdlib>
 
 using namespace lld;
 using namespace llvm;
@@ -104,13 +113,18 @@ static Flavor parseFlavor(std::vector<const char *> &V) {
   return parseProgname(Arg0);
 }
 
+// If this function returns true, lld calls _exit() so that it quickly
+// exits without invoking destructors of globally allocated objects.
+//
+// We don't want to do that if we are running tests though, because
+// doing that breaks leak sanitizer. So, lit sets this environment variable,
+// and we use it to detect whether we are running tests or not.
+static bool canExitEarly() { return StringRef(getenv("LLD_IN_TEST")) != "1"; }
+
 /// Universal linker main(). This linker emulates the gnu, darwin, or
 /// windows linker based on the argv[0] or -flavor option.
 int main(int Argc, const char **Argv) {
-  // Standard set up, so program fails gracefully.
-  sys::PrintStackTraceOnErrorSignal(Argv[0]);
-  PrettyStackTraceProgram StackPrinter(Argc, Argv);
-  llvm_shutdown_obj Shutdown;
+  InitLLVM X(Argc, Argv);
 
   std::vector<const char *> Args(Argv, Argv + Argc);
   switch (parseFlavor(Args)) {
@@ -119,17 +133,18 @@ int main(int Argc, const char **Argv) {
     if (isPETarget(Args))
       return !mingw::link(Args);
 #endif
-    return !elf::link(Args, true);
+    return !elf::link(Args, canExitEarly());
 #ifndef __OpenBSD__
   case WinLink:
-    return !coff::link(Args, true);
+    return !coff::link(Args, canExitEarly());
   case Darwin:
-    return !mach_o::link(Args);
+    return !mach_o::link(Args, canExitEarly());
   case Wasm:
-    return !wasm::link(Args, true);
+    return !wasm::link(Args, canExitEarly());
 #endif
   default:
     die("lld is a generic driver.\n"
-        "Invoke ld.lld (Unix), ld (macOS) or lld-link (Windows) instead.");
+        "Invoke ld.lld (Unix), ld64.lld (macOS), lld-link (Windows), wasm-lld"
+        " (WebAssembly) instead");
   }
 }