Merge LLVM 5.0.0 release.

9 files changed, 2273 insertions, 1874 deletions

diff --git a/gnu/llvm/tools/lld/ELF/Config.h b/gnu/llvm/tools/lld/ELF/Config.h
index f58e3e5715b..23627dd812d 100644
--- a/gnu/llvm/tools/lld/ELF/Config.h
+++ b/gnu/llvm/tools/lld/ELF/Config.h
@@ -13,7 +13,10 @@
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSet.h"
-#include "llvm/Support/ELF.h"
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/Support/CachePruning.h"
+#include "llvm/Support/CodeGen.h"
+#include "llvm/Support/Endian.h"
 
 #include <vector>
 
@@ -34,14 +37,14 @@ enum ELFKind {
 // For --build-id.
 enum class BuildIdKind { None, Fast, Md5, Sha1, Hexstring, Uuid };
 
-// For --discard-{all,locals,none} and --retain-symbols-file.
-enum class DiscardPolicy { Default, All, Locals, RetainFile, None };
+// For --discard-{all,locals,none}.
+enum class DiscardPolicy { Default, All, Locals, None };
 
 // For --strip-{all,debug}.
 enum class StripPolicy { None, All, Debug };
 
 // For --unresolved-symbols.
-enum class UnresolvedPolicy { NoUndef, ReportError, Warn, Ignore };
+enum class UnresolvedPolicy { ReportError, Warn, WarnAll, Ignore, IgnoreAll };
 
 // For --sort-section and linkerscript sorting rules.
 enum class SortSectionPolicy { Default, None, Alignment, Name, Priority };
@@ -58,11 +61,16 @@ struct SymbolVersion {
 // This struct contains symbols version definition that
 // can be found in version script if it is used for link.
 struct VersionDefinition {
-  VersionDefinition(llvm::StringRef Name, uint16_t Id) : Name(Name), Id(Id) {}
   llvm::StringRef Name;
-  uint16_t Id;
+  uint16_t Id = 0;
   std::vector<SymbolVersion> Globals;
-  size_t NameOff; // Offset in string table.
+  size_t NameOff = 0; // Offset in the string table
+};
+
+// Structure for mapping renamed symbols
+struct RenamedSymbol {
+  Symbol *Target;
+  uint8_t OriginalBinding;
 };
 
 // This struct contains the global configuration for the linker.
@@ -72,6 +80,7 @@ struct VersionDefinition {
 struct Configuration {
   InputFile *FirstElf = nullptr;
   uint8_t OSABI = 0;
+  llvm::CachePruningPolicy ThinLTOCachePolicy;
   llvm::StringMap<uint64_t> SectionStartMap;
   llvm::StringRef DynamicLinker;
   llvm::StringRef Entry;
@@ -80,52 +89,57 @@ struct Configuration {
   llvm::StringRef Init;
   llvm::StringRef LTOAAPipeline;
   llvm::StringRef LTONewPmPasses;
+  llvm::StringRef MapFile;
   llvm::StringRef OutputFile;
+  llvm::StringRef OptRemarksFilename;
   llvm::StringRef SoName;
   llvm::StringRef Sysroot;
-  llvm::StringSet<> RetainSymbolsFile;
-  std::string RPath;
+  llvm::StringRef ThinLTOCacheDir;
+  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;
   std::vector<llvm::StringRef> SymbolOrderingFile;
   std::vector<llvm::StringRef> Undefined;
   std::vector<SymbolVersion> VersionScriptGlobals;
   std::vector<SymbolVersion> VersionScriptLocals;
   std::vector<uint8_t> BuildIdVector;
+  llvm::MapVector<Symbol *, RenamedSymbol> RenamedSymbols;
   bool AllowMultipleDefinition;
   bool AsNeeded = false;
   bool Bsymbolic;
   bool BsymbolicFunctions;
   bool ColorDiagnostics = false;
+  bool CompressDebugSections;
   bool DefineCommon;
   bool Demangle = true;
   bool DisableVerify;
   bool EhFrameHdr;
+  bool EmitRelocs;
   bool EnableNewDtags;
   bool ExportDynamic;
   bool FatalWarnings;
   bool GcSections;
   bool GdbIndex;
-  bool GnuHash = false;
+  bool GnuHash;
   bool ICF;
-  bool Mips64EL = false;
   bool MipsN32Abi = false;
   bool NoGnuUnique;
   bool NoUndefinedVersion;
   bool Nostdlib;
   bool OFormatBinary;
-  bool OMagic;
-  bool Pic;
+  bool Omagic;
+  bool OptRemarksWithHotness;
   bool Pie;
   bool PrintGcSections;
-  bool Rela;
   bool Relocatable;
   bool SaveTemps;
   bool SingleRoRx;
   bool Shared;
   bool Static = false;
-  bool SysvHash = true;
+  bool SysvHash;
   bool Target1Rel;
   bool Threads;
   bool Trace;
@@ -134,18 +148,21 @@ struct Configuration {
   bool WarnMissingEntry;
   bool ZCombreloc;
   bool ZExecstack;
+  bool ZNocopyreloc;
   bool ZNodelete;
   bool ZNodlopen;
   bool ZNow;
   bool ZOrigin;
   bool ZRelro;
+  bool ZRodynamic;
+  bool ZText;
   bool ExitEarly;
   bool ZWxneeded;
   DiscardPolicy Discard;
   SortSectionPolicy SortSection;
-  StripPolicy Strip = StripPolicy::None;
+  StripPolicy Strip;
   UnresolvedPolicy UnresolvedSymbols;
-  Target2Policy Target2 = Target2Policy::GotRel;
+  Target2Policy Target2;
   BuildIdKind BuildId = BuildIdKind::None;
   ELFKind EKind = ELFNoneKind;
   uint16_t DefaultSymbolVersion = llvm::ELF::VER_NDX_GLOBAL;
@@ -158,6 +175,58 @@ struct Configuration {
   unsigned LTOO;
   unsigned Optimize;
   unsigned ThinLTOJobs;
+
+  // The following config options do not directly correspond to any
+  // particualr command line options.
+
+  // True if we need to pass through relocations in input files to the
+  // output file. Usually false because we consume relocations.
+  bool CopyRelocs;
+
+  // True if the target is ELF64. False if ELF32.
+  bool Is64;
+
+  // True if the target is little-endian. False if big-endian.
+  bool IsLE;
+
+  // endianness::little if IsLE is true. endianness::big otherwise.
+  llvm::support::endianness Endianness;
+
+  // True if the target is the little-endian MIPS64.
+  //
+  // The reason why we have this variable only for the MIPS is because
+  // we use this often.  Some ELF headers for MIPS64EL are in a
+  // mixed-endian (which is horrible and I'd say that's a serious spec
+  // bug), and we need to know whether we are reading MIPS ELF files or
+  // not in various places.
+  //
+  // (Note that MIPS64EL is not a typo for MIPS64LE. This is the official
+  // name whatever that means. A fun hypothesis is that "EL" is short for
+  // little-endian written in the little-endian order, but I don't know
+  // if that's true.)
+  bool IsMips64EL;
+
+  // The ELF spec defines two types of relocation table entries, RELA and
+  // REL. RELA is a triplet of (offset, info, addend) while REL is a
+  // tuple of (offset, info). Addends for REL are implicit and read from
+  // the location where the relocations are applied. So, REL is more
+  // compact than RELA but requires a bit of more work to process.
+  //
+  // (From the linker writer's view, this distinction is not necessary.
+  // If the ELF had chosen whichever and sticked with it, it would have
+  // been easier to write code to process relocations, but it's too late
+  // to change the spec.)
+  //
+  // Each ABI defines its relocation type. IsRela is true if target
+  // uses RELA. As far as we know, all 64-bit ABIs are using RELA. A
+  // few 32-bit ABIs are using RELA too.
+  bool IsRela;
+
+  // True if we are creating position-independent code.
+  bool Pic;
+
+  // 4 for ELF32, 8 for ELF64.
+  int Wordsize;
 };
 
 // The only instance of Configuration struct.
diff --git a/gnu/llvm/tools/lld/ELF/Driver.cpp b/gnu/llvm/tools/lld/ELF/Driver.cpp
index 99253313c35..a069bd637e7 100644
--- a/gnu/llvm/tools/lld/ELF/Driver.cpp
+++ b/gnu/llvm/tools/lld/ELF/Driver.cpp
@@ -6,17 +6,37 @@
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
+//
+// The driver drives the entire linking process. It is responsible for
+// parsing command line options and doing whatever it is instructed to do.
+//
+// One notable thing in the LLD's driver when compared to other linkers is
+// that the LLD's driver is agnostic on the host operating system.
+// Other linkers usually have implicit default values (such as a dynamic
+// linker path or library paths) for each host OS.
+//
+// I don't think implicit default values are useful because they are
+// usually explicitly specified by the compiler driver. They can even
+// be harmful when you are doing cross-linking. Therefore, in LLD, we
+// simply trust the compiler driver to pass all required options and
+// don't try to make effort on our side.
+//
+//===----------------------------------------------------------------------===//
 
 #include "Driver.h"
 #include "Config.h"
 #include "Error.h"
+#include "Filesystem.h"
 #include "ICF.h"
 #include "InputFiles.h"
 #include "InputSection.h"
 #include "LinkerScript.h"
 #include "Memory.h"
+#include "OutputSections.h"
+#include "ScriptParser.h"
 #include "Strings.h"
 #include "SymbolTable.h"
+#include "SyntheticSections.h"
 #include "Target.h"
 #include "Threads.h"
 #include "Writer.h"
@@ -24,8 +44,8 @@
 #include "lld/Driver/Driver.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
-#include "llvm/Object/Decompressor.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compression.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/TarWriter.h"
 #include "llvm/Support/TargetSelect.h"
@@ -48,16 +68,19 @@ BumpPtrAllocator elf::BAlloc;
 StringSaver elf::Saver{BAlloc};
 std::vector<SpecificAllocBase *> elf::SpecificAllocBase::Instances;
 
+static void setConfigs();
+
 bool elf::link(ArrayRef<const char *> Args, bool CanExitEarly,
                raw_ostream &Error) {
   ErrorCount = 0;
   ErrorOS = &Error;
-  Argv0 = Args[0];
+  InputSections.clear();
   Tar = nullptr;
 
   Config = make<Configuration>();
   Driver = make<LinkerDriver>();
-  ScriptConfig = make<ScriptConfiguration>();
+  Script = make<LinkerScript>();
+  Config->Argv = {Args.begin(), Args.end()};
 
   Driver->main(Args, CanExitEarly);
   freeArena();
@@ -76,12 +99,10 @@ 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})
-          .Case("armelf_linux_eabi", {ELF32LEKind, EM_ARM})
+          .Cases("armelf", "armelf_linux_eabi", {ELF32LEKind, EM_ARM})
           .Case("elf32_x86_64", {ELF32LEKind, EM_X86_64})
-          .Case("elf32btsmip", {ELF32BEKind, EM_MIPS})
-          .Case("elf32ltsmip", {ELF32LEKind, EM_MIPS})
-          .Case("elf32btsmipn32", {ELF32BEKind, EM_MIPS})
-          .Case("elf32ltsmipn32", {ELF32LEKind, EM_MIPS})
+          .Cases("elf32btsmip", "elf32btsmipn32", {ELF32BEKind, EM_MIPS})
+          .Cases("elf32ltsmip", "elf32ltsmipn32", {ELF32LEKind, EM_MIPS})
           .Case("elf32ppc", {ELF32BEKind, EM_PPC})
           .Case("elf64btsmip", {ELF64BEKind, EM_MIPS})
           .Case("elf64ltsmip", {ELF64LEKind, EM_MIPS})
@@ -102,13 +123,13 @@ static std::tuple<ELFKind, uint16_t, uint8_t> parseEmulation(StringRef Emul) {
 
 // Returns slices of MB by parsing MB as an archive file.
 // Each slice consists of a member file in the archive.
-std::vector<MemoryBufferRef>
-LinkerDriver::getArchiveMembers(MemoryBufferRef MB) {
+std::vector<std::pair<MemoryBufferRef, uint64_t>> static getArchiveMembers(
+    MemoryBufferRef MB) {
   std::unique_ptr<Archive> File =
       check(Archive::create(MB),
             MB.getBufferIdentifier() + ": failed to parse archive");
 
-  std::vector<MemoryBufferRef> V;
+  std::vector<std::pair<MemoryBufferRef, uint64_t>> V;
   Error Err = Error::success();
   for (const ErrorOr<Archive::Child> &COrErr : File->children(Err)) {
     Archive::Child C =
@@ -118,7 +139,7 @@ LinkerDriver::getArchiveMembers(MemoryBufferRef MB) {
         check(C.getMemoryBufferRef(),
               MB.getBufferIdentifier() +
                   ": could not get the buffer for a child of the archive");
-    V.push_back(MBRef);
+    V.push_back(std::make_pair(MBRef, C.getChildOffset()));
   }
   if (Err)
     fatal(MB.getBufferIdentifier() + ": Archive::children failed: " +
@@ -131,9 +152,8 @@ LinkerDriver::getArchiveMembers(MemoryBufferRef MB) {
   return V;
 }
 
-// Opens and parses a file. Path has to be resolved already.
-// Newly created memory buffers are owned by this driver.
-void LinkerDriver::addFile(StringRef Path) {
+// Opens a file and create a file object. Path has to be resolved already.
+void LinkerDriver::addFile(StringRef Path, bool WithLOption) {
   using namespace sys::fs;
 
   Optional<MemoryBufferRef> Buffer = readFile(Path);
@@ -150,24 +170,53 @@ void LinkerDriver::addFile(StringRef Path) {
   case file_magic::unknown:
     readLinkerScript(MBRef);
     return;
-  case file_magic::archive:
+  case file_magic::archive: {
+    // Handle -whole-archive.
     if (InWholeArchive) {
-      for (MemoryBufferRef MB : getArchiveMembers(MBRef))
-        Files.push_back(createObjectFile(MB, Path));
+      for (const auto &P : getArchiveMembers(MBRef))
+        Files.push_back(createObjectFile(P.first, Path, P.second));
       return;
     }
-    Files.push_back(make<ArchiveFile>(MBRef));
+
+    std::unique_ptr<Archive> File =
+        check(Archive::create(MBRef), Path + ": failed to parse archive");
+
+    // If an archive file has no symbol table, it is likely that a user
+    // is attempting LTO and using a default ar command that doesn't
+    // understand the LLVM bitcode file. It is a pretty common error, so
+    // we'll handle it as if it had a symbol table.
+    if (!File->isEmpty() && !File->hasSymbolTable()) {
+      for (const auto &P : getArchiveMembers(MBRef))
+        Files.push_back(make<LazyObjectFile>(P.first, Path, P.second));
+      return;
+    }
+
+    // Handle the regular case.
+    Files.push_back(make<ArchiveFile>(std::move(File)));
     return;
+  }
   case file_magic::elf_shared_object:
     if (Config->Relocatable) {
       error("attempted static link of dynamic object " + Path);
       return;
     }
-    Files.push_back(createSharedFile(MBRef));
+
+    // DSOs usually have DT_SONAME tags in their ELF headers, and the
+    // sonames are used to identify DSOs. But if they are missing,
+    // they are identified by filenames. We don't know whether the new
+    // file has a DT_SONAME or not because we haven't parsed it yet.
+    // Here, we set the default soname for the file because we might
+    // need it later.
+    //
+    // If a file was specified by -lfoo, the directory part is not
+    // significant, as a user did not specify it. This behavior is
+    // compatible with GNU.
+    Files.push_back(
+        createSharedFile(MBRef, WithLOption ? path::filename(Path) : Path));
     return;
   default:
     if (InLib)
-      Files.push_back(make<LazyObjectFile>(MBRef));
+      Files.push_back(make<LazyObjectFile>(MBRef, "", 0));
     else
       Files.push_back(createObjectFile(MBRef));
   }
@@ -176,7 +225,7 @@ void LinkerDriver::addFile(StringRef Path) {
 // Add a given library by searching it from input search paths.
 void LinkerDriver::addLibrary(StringRef Name) {
   if (Optional<std::string> Path = searchLibrary(Name))
-    addFile(*Path);
+    addFile(*Path, /*WithLOption=*/true);
   else
     error("unable to find library -l" + Name);
 }
@@ -210,6 +259,12 @@ static void checkOptions(opt::InputArgList &Args) {
   if (Config->Pie && Config->Shared)
     error("-shared and -pie may not be used together");
 
+  if (!Config->Shared && !Config->FilterList.empty())
+    error("-F may not be used without -shared");
+
+  if (!Config->Shared && !Config->AuxiliaryList.empty())
+    error("-f may not be used without -shared");
+
   if (Config->Relocatable) {
     if (Config->Shared)
       error("-r and -shared may not be used together");
@@ -222,18 +277,11 @@ static void checkOptions(opt::InputArgList &Args) {
   }
 }
 
-static StringRef getString(opt::InputArgList &Args, unsigned Key,
-                           StringRef Default = "") {
-  if (auto *Arg = Args.getLastArg(Key))
-    return Arg->getValue();
-  return Default;
-}
-
 static int getInteger(opt::InputArgList &Args, unsigned Key, int Default) {
   int V = Default;
   if (auto *Arg = Args.getLastArg(Key)) {
     StringRef S = Arg->getValue();
-    if (S.getAsInteger(10, V))
+    if (!to_integer(S, V, 10))
       error(Arg->getSpelling() + ": number expected, but got " + S);
   }
   return V;
@@ -255,13 +303,11 @@ static bool hasZOption(opt::InputArgList &Args, StringRef Key) {
 static uint64_t getZOptionValue(opt::InputArgList &Args, StringRef Key,
                                 uint64_t Default) {
   for (auto *Arg : Args.filtered(OPT_z)) {
-    StringRef Value = Arg->getValue();
-    size_t Pos = Value.find("=");
-    if (Pos != StringRef::npos && Key == Value.substr(0, Pos)) {
-      Value = Value.substr(Pos + 1);
-      uint64_t Result;
-      if (Value.getAsInteger(0, Result))
-        error("invalid " + Key + ": " + Value);
+    std::pair<StringRef, StringRef> KV = StringRef(Arg->getValue()).split('=');
+    if (KV.first == Key) {
+      uint64_t Result = Default;
+      if (!to_integer(KV.second, Result))
+        error("invalid " + Key + ": " + KV.second);
       return Result;
     }
   }
@@ -296,8 +342,8 @@ void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
   // lot of "configure" scripts out there that are generated by old version
   // of Libtool. We cannot convince every software developer to migrate to
   // the latest version and re-generate scripts. So we have this hack.
-  if (Args.hasArg(OPT_version) || Args.hasArg(OPT_v))
-    outs() << getLLDVersion() << " (compatible with GNU linkers)\n";
+  if (Args.hasArg(OPT_v) || Args.hasArg(OPT_version))
+    message(getLLDVersion() + " (compatible with GNU linkers)");
 
   // ld.bfd always exits after printing out the version string.
   // ld.gold proceeds if a given option is -v. Because gold's behavior
@@ -327,6 +373,7 @@ void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
   initLLVM(Args);
   createFiles(Args);
   inferMachineType();
+  setConfigs();
   checkOptions(Args);
   if (ErrorCount)
     return;
@@ -349,36 +396,76 @@ void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
   }
 }
 
-static UnresolvedPolicy getUnresolvedSymbolOption(opt::InputArgList &Args) {
+static bool getArg(opt::InputArgList &Args, unsigned K1, unsigned K2,
+                   bool Default) {
+  if (auto *Arg = Args.getLastArg(K1, K2))
+    return Arg->getOption().getID() == K1;
+  return Default;
+}
+
+static std::vector<StringRef> getArgs(opt::InputArgList &Args, int Id) {
+  std::vector<StringRef> V;
+  for (auto *Arg : Args.filtered(Id))
+    V.push_back(Arg->getValue());
+  return V;
+}
+
+static std::string getRpath(opt::InputArgList &Args) {
+  std::vector<StringRef> V = getArgs(Args, OPT_rpath);
+  return llvm::join(V.begin(), V.end(), ":");
+}
+
+// Determines what we should do if there are remaining unresolved
+// symbols after the name resolution.
+static UnresolvedPolicy getUnresolvedSymbolPolicy(opt::InputArgList &Args) {
+  // -noinhibit-exec or -r imply some default values.
   if (Args.hasArg(OPT_noinhibit_exec))
-    return UnresolvedPolicy::Warn;
-  if (Args.hasArg(OPT_no_undefined) || hasZOption(Args, "defs"))
-    return UnresolvedPolicy::NoUndef;
-  if (Config->Relocatable)
-    return UnresolvedPolicy::Ignore;
+    return UnresolvedPolicy::WarnAll;
+  if (Args.hasArg(OPT_relocatable))
+    return UnresolvedPolicy::IgnoreAll;
 
-  if (auto *Arg = Args.getLastArg(OPT_unresolved_symbols)) {
-    StringRef S = Arg->getValue();
-    if (S == "ignore-all" || S == "ignore-in-object-files")
-      return UnresolvedPolicy::Ignore;
-    if (S == "ignore-in-shared-libs" || S == "report-all")
-      return UnresolvedPolicy::ReportError;
-    error("unknown --unresolved-symbols value: " + S);
+  UnresolvedPolicy ErrorOrWarn = getArg(Args, OPT_error_unresolved_symbols,
+                                        OPT_warn_unresolved_symbols, true)
+                                     ? UnresolvedPolicy::ReportError
+                                     : UnresolvedPolicy::Warn;
+
+  // Process the last of -unresolved-symbols, -no-undefined or -z defs.
+  for (auto *Arg : llvm::reverse(Args)) {
+    switch (Arg->getOption().getID()) {
+    case OPT_unresolved_symbols: {
+      StringRef S = Arg->getValue();
+      if (S == "ignore-all" || S == "ignore-in-object-files")
+        return UnresolvedPolicy::Ignore;
+      if (S == "ignore-in-shared-libs" || S == "report-all")
+        return ErrorOrWarn;
+      error("unknown --unresolved-symbols value: " + S);
+      continue;
+    }
+    case OPT_no_undefined:
+      return ErrorOrWarn;
+    case OPT_z:
+      if (StringRef(Arg->getValue()) == "defs")
+        return ErrorOrWarn;
+      continue;
+    }
   }
-  return UnresolvedPolicy::ReportError;
+
+  // -shared implies -unresolved-symbols=ignore-all because missing
+  // symbols are likely to be resolved at runtime using other DSOs.
+  if (Config->Shared)
+    return UnresolvedPolicy::Ignore;
+  return ErrorOrWarn;
 }
 
-static Target2Policy getTarget2Option(opt::InputArgList &Args) {
-  if (auto *Arg = Args.getLastArg(OPT_target2)) {
-    StringRef S = Arg->getValue();
-    if (S == "rel")
-      return Target2Policy::Rel;
-    if (S == "abs")
-      return Target2Policy::Abs;
-    if (S == "got-rel")
-      return Target2Policy::GotRel;
-    error("unknown --target2 option: " + S);
-  }
+static Target2Policy getTarget2(opt::InputArgList &Args) {
+  StringRef S = Args.getLastArgValue(OPT_target2, "got-rel");
+  if (S == "rel")
+    return Target2Policy::Rel;
+  if (S == "abs")
+    return Target2Policy::Abs;
+  if (S == "got-rel")
+    return Target2Policy::GotRel;
+  error("unknown --target2 option: " + S);
   return Target2Policy::GotRel;
 }
 
@@ -392,16 +479,10 @@ static bool isOutputFormatBinary(opt::InputArgList &Args) {
   return false;
 }
 
-static bool getArg(opt::InputArgList &Args, unsigned K1, unsigned K2,
-                   bool Default) {
-  if (auto *Arg = Args.getLastArg(K1, K2))
-    return Arg->getOption().getID() == K1;
-  return Default;
-}
-
-static DiscardPolicy getDiscardOption(opt::InputArgList &Args) {
-  if (Config->Relocatable)
+static DiscardPolicy getDiscard(opt::InputArgList &Args) {
+  if (Args.hasArg(OPT_relocatable))
     return DiscardPolicy::None;
+
   auto *Arg =
       Args.getLastArg(OPT_discard_all, OPT_discard_locals, OPT_discard_none);
   if (!Arg)
@@ -413,20 +494,30 @@ static DiscardPolicy getDiscardOption(opt::InputArgList &Args) {
   return DiscardPolicy::None;
 }
 
-static StripPolicy getStripOption(opt::InputArgList &Args) {
-  if (auto *Arg = Args.getLastArg(OPT_strip_all, OPT_strip_debug)) {
-    if (Arg->getOption().getID() == OPT_strip_all)
-      return StripPolicy::All;
-    return StripPolicy::Debug;
-  }
-  return StripPolicy::None;
+static StringRef getDynamicLinker(opt::InputArgList &Args) {
+  auto *Arg = Args.getLastArg(OPT_dynamic_linker, OPT_no_dynamic_linker);
+  if (!Arg || Arg->getOption().getID() == OPT_no_dynamic_linker)
+    return "";
+  return Arg->getValue();
+}
+
+static StripPolicy getStrip(opt::InputArgList &Args) {
+  if (Args.hasArg(OPT_relocatable))
+    return StripPolicy::None;
+
+  auto *Arg = Args.getLastArg(OPT_strip_all, OPT_strip_debug);
+  if (!Arg)
+    return StripPolicy::None;
+  if (Arg->getOption().getID() == OPT_strip_all)
+    return StripPolicy::All;
+  return StripPolicy::Debug;
 }
 
 static uint64_t parseSectionAddress(StringRef S, opt::Arg *Arg) {
   uint64_t VA = 0;
   if (S.startswith("0x"))
     S = S.drop_front(2);
-  if (S.getAsInteger(16, VA))
+  if (!to_integer(S, VA, 16))
     error("invalid argument: " + toString(Arg));
   return VA;
 }
@@ -449,8 +540,8 @@ static StringMap<uint64_t> getSectionStartMap(opt::InputArgList &Args) {
   return Ret;
 }
 
-static SortSectionPolicy getSortKind(opt::InputArgList &Args) {
-  StringRef S = getString(Args, OPT_sort_section);
+static SortSectionPolicy getSortSection(opt::InputArgList &Args) {
+  StringRef S = Args.getLastArgValue(OPT_sort_section);
   if (S == "alignment")
     return SortSectionPolicy::Alignment;
   if (S == "name")
@@ -460,6 +551,44 @@ static SortSectionPolicy getSortKind(opt::InputArgList &Args) {
   return SortSectionPolicy::Default;
 }
 
+static std::pair<bool, bool> getHashStyle(opt::InputArgList &Args) {
+  StringRef S = Args.getLastArgValue(OPT_hash_style, "sysv");
+  if (S == "sysv")
+    return {true, false};
+  if (S == "gnu")
+    return {false, true};
+  if (S != "both")
+    error("unknown -hash-style: " + S);
+  return {true, true};
+}
+
+// Parse --build-id or --build-id=<style>. We handle "tree" as a
+// synonym for "sha1" because all our hash functions including
+// -build-id=sha1 are actually tree hashes for performance reasons.
+static std::pair<BuildIdKind, std::vector<uint8_t>>
+getBuildId(opt::InputArgList &Args) {
+  auto *Arg = Args.getLastArg(OPT_build_id, OPT_build_id_eq);
+  if (!Arg)
+    return {BuildIdKind::None, {}};
+
+  if (Arg->getOption().getID() == OPT_build_id)
+    return {BuildIdKind::Fast, {}};
+
+  StringRef S = Arg->getValue();
+  if (S == "md5")
+    return {BuildIdKind::Md5, {}};
+  if (S == "sha1" || S == "tree")
+    return {BuildIdKind::Sha1, {}};
+  if (S == "uuid")
+    return {BuildIdKind::Uuid, {}};
+  if (S.startswith("0x"))
+    return {BuildIdKind::Hexstring, parseHex(S.substr(2))};
+
+  if (S != "none")
+    error("unknown --build-id style: " + S);
+  return {BuildIdKind::None, {}};
+}
+
 static std::vector<StringRef> getLines(MemoryBufferRef MB) {
   SmallVector<StringRef, 0> Arr;
   MB.getBuffer().split(Arr, '\n');
@@ -473,42 +602,58 @@ static std::vector<StringRef> getLines(MemoryBufferRef MB) {
   return Ret;
 }
 
+static bool getCompressDebugSections(opt::InputArgList &Args) {
+  StringRef S = Args.getLastArgValue(OPT_compress_debug_sections, "none");
+  if (S == "none")
+    return false;
+  if (S != "zlib")
+    error("unknown --compress-debug-sections value: " + S);
+  if (!zlib::isAvailable())
+    error("--compress-debug-sections: zlib is not available");
+  return true;
+}
+
 // Initializes Config members by the command line options.
 void LinkerDriver::readConfigs(opt::InputArgList &Args) {
-  for (auto *Arg : Args.filtered(OPT_L))
-    Config->SearchPaths.push_back(Arg->getValue());
-
-  std::vector<StringRef> RPaths;
-  for (auto *Arg : Args.filtered(OPT_rpath))
-    RPaths.push_back(Arg->getValue());
-  if (!RPaths.empty())
-    Config->RPath = llvm::join(RPaths.begin(), RPaths.end(), ":");
-
-  if (auto *Arg = Args.getLastArg(OPT_m)) {
-    // Parse ELF{32,64}{LE,BE} and CPU type.
-    StringRef S = Arg->getValue();
-    std::tie(Config->EKind, Config->EMachine, Config->OSABI) =
-        parseEmulation(S);
-    Config->MipsN32Abi = (S == "elf32btsmipn32" || S == "elf32ltsmipn32");
-    Config->Emulation = S;
-  }
-
   Config->AllowMultipleDefinition = Args.hasArg(OPT_allow_multiple_definition);
+  Config->AuxiliaryList = getArgs(Args, OPT_auxiliary);
   Config->Bsymbolic = Args.hasArg(OPT_Bsymbolic);
   Config->BsymbolicFunctions = Args.hasArg(OPT_Bsymbolic_functions);
+  Config->CompressDebugSections = getCompressDebugSections(Args);
+  Config->DefineCommon = getArg(Args, OPT_define_common, OPT_no_define_common,
+                                !Args.hasArg(OPT_relocatable));
   Config->Demangle = getArg(Args, OPT_demangle, OPT_no_demangle, true);
   Config->DisableVerify = Args.hasArg(OPT_disable_verify);
+  Config->Discard = getDiscard(Args);
+  Config->DynamicLinker = getDynamicLinker(Args);
   Config->EhFrameHdr = Args.hasArg(OPT_eh_frame_hdr);
+  Config->EmitRelocs = Args.hasArg(OPT_emit_relocs);
   Config->EnableNewDtags = !Args.hasArg(OPT_disable_new_dtags);
-  Config->ExportDynamic = Args.hasArg(OPT_export_dynamic);
-  Config->FatalWarnings = Args.hasArg(OPT_fatal_warnings);
+  Config->Entry = Args.getLastArgValue(OPT_entry);
+  Config->ExportDynamic =
+      getArg(Args, OPT_export_dynamic, OPT_no_export_dynamic, false);
+  Config->FatalWarnings =
+      getArg(Args, OPT_fatal_warnings, OPT_no_fatal_warnings, false);
+  Config->FilterList = getArgs(Args, OPT_filter);
+  Config->Fini = Args.getLastArgValue(OPT_fini, "_fini");
   Config->GcSections = getArg(Args, OPT_gc_sections, OPT_no_gc_sections, false);
   Config->GdbIndex = Args.hasArg(OPT_gdb_index);
-  Config->ICF = Args.hasArg(OPT_icf);
+  Config->ICF = getArg(Args, OPT_icf_all, OPT_icf_none, false);
+  Config->Init = Args.getLastArgValue(OPT_init, "_init");
+  Config->LTOAAPipeline = Args.getLastArgValue(OPT_lto_aa_pipeline);
+  Config->LTONewPmPasses = Args.getLastArgValue(OPT_lto_newpm_passes);
+  Config->LTOO = getInteger(Args, OPT_lto_O, 2);
+  Config->LTOPartitions = getInteger(Args, OPT_lto_partitions, 1);
+  Config->MapFile = Args.getLastArgValue(OPT_Map);
   Config->NoGnuUnique = Args.hasArg(OPT_no_gnu_unique);
   Config->NoUndefinedVersion = Args.hasArg(OPT_no_undefined_version);
   Config->Nostdlib = Args.hasArg(OPT_nostdlib);
-  Config->OMagic = Args.hasArg(OPT_omagic);
+  Config->OFormatBinary = isOutputFormatBinary(Args);
+  Config->Omagic = Args.hasArg(OPT_omagic);
+  Config->OptRemarksFilename = Args.getLastArgValue(OPT_opt_remarks_filename);
+  Config->OptRemarksWithHotness = Args.hasArg(OPT_opt_remarks_with_hotness);
+  Config->Optimize = getInteger(Args, OPT_O, 1);
+  Config->OutputFile = Args.getLastArgValue(OPT_o);
 #ifdef __OpenBSD__
   Config->Pie = getArg(Args, OPT_pie, OPT_nopie,
       !Args.hasArg(OPT_shared) && !Args.hasArg(OPT_relocatable));
@@ -516,137 +661,111 @@ void LinkerDriver::readConfigs(opt::InputArgList &Args) {
   Config->Pie = getArg(Args, OPT_pie, OPT_nopie, false);
 #endif
   Config->PrintGcSections = Args.hasArg(OPT_print_gc_sections);
+  Config->Rpath = getRpath(Args);
   Config->Relocatable = Args.hasArg(OPT_relocatable);
-  Config->DefineCommon = getArg(Args, OPT_define_common, OPT_no_define_common,
-                                !Config->Relocatable);
-  Config->Discard = getDiscardOption(Args);
   Config->SaveTemps = Args.hasArg(OPT_save_temps);
-  Config->SingleRoRx = Args.hasArg(OPT_no_rosegment);
+  Config->SearchPaths = getArgs(Args, OPT_L);
+  Config->SectionStartMap = getSectionStartMap(Args);
   Config->Shared = Args.hasArg(OPT_shared);
+  Config->SingleRoRx = Args.hasArg(OPT_no_rosegment);
+  Config->SoName = Args.getLastArgValue(OPT_soname);
+  Config->SortSection = getSortSection(Args);
+  Config->Strip = getStrip(Args);
+  Config->Sysroot = Args.getLastArgValue(OPT_sysroot);
   Config->Target1Rel = getArg(Args, OPT_target1_rel, OPT_target1_abs, false);
+  Config->Target2 = getTarget2(Args);
+  Config->ThinLTOCacheDir = Args.getLastArgValue(OPT_thinlto_cache_dir);
+  Config->ThinLTOCachePolicy = check(
+      parseCachePruningPolicy(Args.getLastArgValue(OPT_thinlto_cache_policy)),
+      "--thinlto-cache-policy: invalid cache policy");
+  Config->ThinLTOJobs = getInteger(Args, OPT_thinlto_jobs, -1u);
   Config->Threads = getArg(Args, OPT_threads, OPT_no_threads, true);
   Config->Trace = Args.hasArg(OPT_trace);
+  Config->Undefined = getArgs(Args, OPT_undefined);
+  Config->UnresolvedSymbols = getUnresolvedSymbolPolicy(Args);
   Config->Verbose = Args.hasArg(OPT_verbose);
   Config->WarnCommon = Args.hasArg(OPT_warn_common);
-
-  Config->DynamicLinker = getString(Args, OPT_dynamic_linker);
-  Config->Entry = getString(Args, OPT_entry);
-  Config->Fini = getString(Args, OPT_fini, "_fini");
-  Config->Init = getString(Args, OPT_init, "_init");
-  Config->LTOAAPipeline = getString(Args, OPT_lto_aa_pipeline);
-  Config->LTONewPmPasses = getString(Args, OPT_lto_newpm_passes);
-  Config->OutputFile = getString(Args, OPT_o);
-  Config->SoName = getString(Args, OPT_soname);
-  Config->Sysroot = getString(Args, OPT_sysroot);
-
-  Config->Optimize = getInteger(Args, OPT_O, 1);
-  Config->LTOO = getInteger(Args, OPT_lto_O, 2);
-  if (Config->LTOO > 3)
-    error("invalid optimization level for LTO: " + getString(Args, OPT_lto_O));
-  Config->LTOPartitions = getInteger(Args, OPT_lto_partitions, 1);
-  if (Config->LTOPartitions == 0)
-    error("--lto-partitions: number of threads must be > 0");
-  Config->ThinLTOJobs = getInteger(Args, OPT_thinlto_jobs, -1u);
-  if (Config->ThinLTOJobs == 0)
-    error("--thinlto-jobs: number of threads must be > 0");
-
   Config->ZCombreloc = !hasZOption(Args, "nocombreloc");
   Config->ZExecstack = hasZOption(Args, "execstack");
+  Config->ZNocopyreloc = hasZOption(Args, "nocopyreloc");
   Config->ZNodelete = hasZOption(Args, "nodelete");
   Config->ZNodlopen = hasZOption(Args, "nodlopen");
   Config->ZNow = hasZOption(Args, "now");
   Config->ZOrigin = hasZOption(Args, "origin");
   Config->ZRelro = !hasZOption(Args, "norelro");
-  Config->ZStackSize = getZOptionValue(Args, "stack-size", -1);
+  Config->ZRodynamic = hasZOption(Args, "rodynamic");
+  Config->ZStackSize = getZOptionValue(Args, "stack-size", 0);
+  Config->ZText = !hasZOption(Args, "notext");
   Config->ZWxneeded = hasZOption(Args, "wxneeded");
 
-  Config->OFormatBinary = isOutputFormatBinary(Args);
-  Config->SectionStartMap = getSectionStartMap(Args);
-  Config->SortSection = getSortKind(Args);
-  Config->Target2 = getTarget2Option(Args);
-  Config->UnresolvedSymbols = getUnresolvedSymbolOption(Args);
+  if (Config->LTOO > 3)
+    error("invalid optimization level for LTO: " +
+          Args.getLastArgValue(OPT_lto_O));
+  if (Config->LTOPartitions == 0)
+    error("--lto-partitions: number of threads must be > 0");
+  if (Config->ThinLTOJobs == 0)
+    error("--thinlto-jobs: number of threads must be > 0");
+
+  if (auto *Arg = Args.getLastArg(OPT_m)) {
+    // Parse ELF{32,64}{LE,BE} and CPU type.
+    StringRef S = Arg->getValue();
+    std::tie(Config->EKind, Config->EMachine, Config->OSABI) =
+        parseEmulation(S);
+    Config->MipsN32Abi = (S == "elf32btsmipn32" || S == "elf32ltsmipn32");
+    Config->Emulation = S;
+  }
+
+  if (Args.hasArg(OPT_print_map))
+    Config->MapFile = "-";
 
   // --omagic is an option to create old-fashioned executables in which
   // .text segments are writable. Today, the option is still in use to
   // create special-purpose programs such as boot loaders. It doesn't
   // make sense to create PT_GNU_RELRO for such executables.
-  if (Config->OMagic)
+  if (Config->Omagic)
     Config->ZRelro = false;
 
-  if (!Config->Relocatable)
-    Config->Strip = getStripOption(Args);
-
-  // Config->Pic is true if we are generating position-independent code.
-  Config->Pic = Config->Pie || Config->Shared;
-
-  if (auto *Arg = Args.getLastArg(OPT_hash_style)) {
-    StringRef S = Arg->getValue();
-    if (S == "gnu") {
-      Config->GnuHash = true;
-      Config->SysvHash = false;
-    } else if (S == "both") {
-      Config->GnuHash = true;
-    } else if (S != "sysv")
-      error("unknown hash style: " + S);
-  }
-
-  // Parse --build-id or --build-id=<style>.
-  if (Args.hasArg(OPT_build_id))
-    Config->BuildId = BuildIdKind::Fast;
-  if (auto *Arg = Args.getLastArg(OPT_build_id_eq)) {
-    StringRef S = Arg->getValue();
-    if (S == "md5") {
-      Config->BuildId = BuildIdKind::Md5;
-    } else if (S == "sha1" || S == "tree") {
-      Config->BuildId = BuildIdKind::Sha1;
-    } else if (S == "uuid") {
-      Config->BuildId = BuildIdKind::Uuid;
-    } else if (S == "none") {
-      Config->BuildId = BuildIdKind::None;
-    } else if (S.startswith("0x")) {
-      Config->BuildId = BuildIdKind::Hexstring;
-      Config->BuildIdVector = parseHex(S.substr(2));
-    } else {
-      error("unknown --build-id style: " + S);
-    }
-  }
-
-  for (auto *Arg : Args.filtered(OPT_auxiliary))
-    Config->AuxiliaryList.push_back(Arg->getValue());
-  if (!Config->Shared && !Config->AuxiliaryList.empty())
-    error("-f may not be used without -shared");
-
-  for (auto *Arg : Args.filtered(OPT_undefined))
-    Config->Undefined.push_back(Arg->getValue());
-
-  if (auto *Arg = Args.getLastArg(OPT_dynamic_list))
-    if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
-      readDynamicList(*Buffer);
+  std::tie(Config->SysvHash, Config->GnuHash) = getHashStyle(Args);
+  std::tie(Config->BuildId, Config->BuildIdVector) = getBuildId(Args);
 
   if (auto *Arg = Args.getLastArg(OPT_symbol_ordering_file))
     if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
       Config->SymbolOrderingFile = getLines(*Buffer);
 
-  // If --retain-symbol-file is used, we'll retail only the symbols listed in
+  // If --retain-symbol-file is used, we'll keep only the symbols listed in
   // the file and discard all others.
   if (auto *Arg = Args.getLastArg(OPT_retain_symbols_file)) {
-    Config->Discard = DiscardPolicy::RetainFile;
+    Config->DefaultSymbolVersion = VER_NDX_LOCAL;
     if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
       for (StringRef S : getLines(*Buffer))
-        Config->RetainSymbolsFile.insert(S);
+        Config->VersionScriptGlobals.push_back(
+            {S, /*IsExternCpp*/ false, /*HasWildcard*/ false});
   }
 
-  for (auto *Arg : Args.filtered(OPT_export_dynamic_symbol))
-    Config->VersionScriptGlobals.push_back(
-        {Arg->getValue(), /*IsExternCpp*/ false, /*HasWildcard*/ false});
-
-  // Dynamic lists are a simplified linker script that doesn't need the
-  // "global:" and implicitly ends with a "local:*". Set the variables needed to
-  // simulate that.
-  if (Args.hasArg(OPT_dynamic_list) || Args.hasArg(OPT_export_dynamic_symbol)) {
-    Config->ExportDynamic = true;
-    if (!Config->Shared)
-      Config->DefaultSymbolVersion = VER_NDX_LOCAL;
+  bool HasExportDynamic =
+      getArg(Args, OPT_export_dynamic, OPT_no_export_dynamic, false);
+
+  // Parses -dynamic-list and -export-dynamic-symbol. They make some
+  // symbols private. Note that -export-dynamic takes precedence over them
+  // as it says all symbols should be exported.
+  if (!HasExportDynamic) {
+    for (auto *Arg : Args.filtered(OPT_dynamic_list))
+      if (Optional<MemoryBufferRef> Buffer = readFile(Arg->getValue()))
+        readDynamicList(*Buffer);
+
+    for (auto *Arg : Args.filtered(OPT_export_dynamic_symbol))
+      Config->VersionScriptGlobals.push_back(
+          {Arg->getValue(), /*IsExternCpp*/ false, /*HasWildcard*/ false});
+
+    // Dynamic lists are a simplified linker script that doesn't need the
+    // "global:" and implicitly ends with a "local:*". Set the variables
+    // needed to simulate that.
+    if (Args.hasArg(OPT_dynamic_list) ||
+        Args.hasArg(OPT_export_dynamic_symbol)) {
+      Config->ExportDynamic = true;
+      if (!Config->Shared)
+        Config->DefaultSymbolVersion = VER_NDX_LOCAL;
+    }
   }
 
   if (auto *Arg = Args.getLastArg(OPT_version_script))
@@ -654,6 +773,29 @@ void LinkerDriver::readConfigs(opt::InputArgList &Args) {
       readVersionScript(*Buffer);
 }
 
+// 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() {
+  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;
+}
+
 // Returns a value of "-format" option.
 static bool getBinaryOption(StringRef S) {
   if (S == "binary")
@@ -672,7 +814,7 @@ void LinkerDriver::createFiles(opt::InputArgList &Args) {
       addLibrary(Arg->getValue());
       break;
     case OPT_INPUT:
-      addFile(Arg->getValue());
+      addFile(Arg->getValue(), /*WithLOption=*/false);
       break;
     case OPT_alias_script_T:
     case OPT_script:
@@ -751,7 +893,7 @@ static uint64_t getImageBase(opt::InputArgList &Args) {
 
   StringRef S = Arg->getValue();
   uint64_t V;
-  if (S.getAsInteger(0, V)) {
+  if (!to_integer(S, V)) {
     error("-image-base: number expected, but got " + S);
     return 0;
   }
@@ -760,18 +902,63 @@ static uint64_t getImageBase(opt::InputArgList &Args) {
   return V;
 }
 
+// Parses --defsym=alias option.
+static std::vector<std::pair<StringRef, StringRef>>
+getDefsym(opt::InputArgList &Args) {
+  std::vector<std::pair<StringRef, StringRef>> Ret;
+  for (auto *Arg : Args.filtered(OPT_defsym)) {
+    StringRef From;
+    StringRef To;
+    std::tie(From, To) = StringRef(Arg->getValue()).split('=');
+    if (!isValidCIdentifier(To))
+      error("--defsym: symbol name expected, but got " + To);
+    Ret.push_back({From, To});
+  }
+  return Ret;
+}
+
+// Parses `--exclude-libs=lib,lib,...`.
+// The library names may be delimited by commas or colons.
+static DenseSet<StringRef> getExcludeLibs(opt::InputArgList &Args) {
+  DenseSet<StringRef> Ret;
+  for (auto *Arg : Args.filtered(OPT_exclude_libs)) {
+    StringRef S = Arg->getValue();
+    for (;;) {
+      size_t Pos = S.find_first_of(",:");
+      if (Pos == StringRef::npos)
+        break;
+      Ret.insert(S.substr(0, Pos));
+      S = S.substr(Pos + 1);
+    }
+    Ret.insert(S);
+  }
+  return Ret;
+}
+
+// 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.
+// A special library name "ALL" means all archive files.
+//
+// This is not a popular option, but some programs such as bionic libc use it.
+static void excludeLibs(opt::InputArgList &Args, ArrayRef<InputFile *> Files) {
+  DenseSet<StringRef> Libs = getExcludeLibs(Args);
+  bool All = Libs.count("ALL");
+
+  for (InputFile *File : Files)
+    if (auto *F = dyn_cast<ArchiveFile>(File))
+      if (All || Libs.count(path::filename(F->getName())))
+        for (Symbol *Sym : F->getSymbols())
+          Sym->VersionId = VER_NDX_LOCAL;
+}
+
 // 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) {
   SymbolTable<ELFT> Symtab;
   elf::Symtab<ELFT>::X = &Symtab;
-  Target = createTarget();
-  ScriptBase = Script<ELFT>::X = make<LinkerScript<ELFT>>();
+  Target = getTarget();
 
-  Config->Rela =
-      ELFT::Is64Bits || Config->EMachine == EM_X86_64 || Config->MipsN32Abi;
-  Config->Mips64EL =
-      (Config->EMachine == EM_MIPS && Config->EKind == ELF64LEKind);
   Config->MaxPageSize = getMaxPageSize(Args);
   Config->ImageBase = getImageBase(Args);
 
@@ -779,6 +966,16 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
   if (Config->OutputFile.empty())
     Config->OutputFile = "a.out";
 
+  // Fail early if the output file or map file is not writable. If a user has a
+  // long link, e.g. due to a large LTO link, they do not wish to run it and
+  // find that it failed because there was a mistake in their command-line.
+  if (auto E = tryCreateFile(Config->OutputFile))
+    error("cannot open output file " + Config->OutputFile + ": " + E.message());
+  if (auto E = tryCreateFile(Config->MapFile))
+    error("cannot open map file " + Config->MapFile + ": " + E.message());
+  if (ErrorCount)
+    return;
+
   // Use default entry point name if no name was given via the command
   // line nor linker scripts. For some reason, MIPS entry point name is
   // different from others.
@@ -806,46 +1003,64 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
   if (ErrorCount)
     return;
 
+  // Handle the `--undefined <sym>` options.
   Symtab.scanUndefinedFlags();
+
+  // Handle undefined symbols in DSOs.
   Symtab.scanShlibUndefined();
+
+  // Handle the -exclude-libs option.
+  if (Args.hasArg(OPT_exclude_libs))
+    excludeLibs(Args, Files);
+
+  // Apply version scripts.
   Symtab.scanVersionScript();
 
+  // Create wrapped symbols for -wrap option.
+  for (auto *Arg : Args.filtered(OPT_wrap))
+    Symtab.addSymbolWrap(Arg->getValue());
+
+  // Create alias symbols for -defsym option.
+  for (std::pair<StringRef, StringRef> &Def : getDefsym(Args))
+    Symtab.addSymbolAlias(Def.first, Def.second);
+
   Symtab.addCombinedLTOObject();
   if (ErrorCount)
     return;
 
-  for (auto *Arg : Args.filtered(OPT_wrap))
-    Symtab.wrap(Arg->getValue());
+  // Some symbols (such as __ehdr_start) are defined lazily only when there
+  // are undefined symbols for them, so we add these to trigger that logic.
+  for (StringRef Sym : Script->Opt.ReferencedSymbols)
+    Symtab.addUndefined(Sym);
+
+  // Apply symbol renames for -wrap and -defsym
+  Symtab.applySymbolRenames();
 
   // Now that we have a complete list of input files.
   // Beyond this point, no new files are added.
   // Aggregate all input sections into one place.
   for (elf::ObjectFile<ELFT> *F : Symtab.getObjectFiles())
-    for (InputSectionBase<ELFT> *S : F->getSections())
-      if (S && S != &InputSection<ELFT>::Discarded)
-        Symtab.Sections.push_back(S);
+    for (InputSectionBase *S : F->getSections())
+      if (S && S != &InputSection::Discarded)
+        InputSections.push_back(S);
   for (BinaryFile *F : Symtab.getBinaryFiles())
-    for (InputSectionData *S : F->getSections())
-      Symtab.Sections.push_back(cast<InputSection<ELFT>>(S));
+    for (InputSectionBase *S : F->getSections())
+      InputSections.push_back(cast<InputSection>(S));
 
-  // Do size optimizations: garbage collection and identical code folding.
+  // This adds a .comment section containing a version string. We have to add it
+  // before decompressAndMergeSections because the .comment section is a
+  // mergeable section.
+  if (!Config->Relocatable)
+    InputSections.push_back(createCommentSection<ELFT>());
+
+  // Do size optimizations: garbage collection, merging of SHF_MERGE sections
+  // and identical code folding.
   if (Config->GcSections)
     markLive<ELFT>();
+  decompressAndMergeSections();
   if (Config->ICF)
     doIcf<ELFT>();
 
-  // MergeInputSection::splitIntoPieces needs to be called before
-  // any call of MergeInputSection::getOffset. Do that.
-  forEach(Symtab.Sections.begin(), Symtab.Sections.end(),
-          [](InputSectionBase<ELFT> *S) {
-            if (!S->Live)
-              return;
-            if (Decompressor::isCompressedELFSection(S->Flags, S->Name))
-              S->uncompress();
-            if (auto *MS = dyn_cast<MergeInputSection<ELFT>>(S))
-              MS->splitIntoPieces();
-          });
-
   // 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 36b4052d72a..2f7d16b2505 100644
--- a/gnu/llvm/tools/lld/ELF/DriverUtils.cpp
+++ b/gnu/llvm/tools/lld/ELF/DriverUtils.cpp
@@ -16,7 +16,6 @@
 #include "Driver.h"
 #include "Error.h"
 #include "Memory.h"
-#include "ScriptParser.h"
 #include "lld/Config/Version.h"
 #include "lld/Core/Reproduce.h"
 #include "llvm/ADT/Optional.h"
@@ -43,9 +42,9 @@ using namespace lld::elf;
 
 // Create table mapping all options defined in Options.td
 static const opt::OptTable::Info OptInfo[] = {
-#define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X6, X7, X8, X9, X10)            \
-  {X1, X2, X9,          X10,         OPT_##ID, opt::Option::KIND##Class,       \
-   X8, X7, OPT_##GROUP, OPT_##ALIAS, X6},
+#define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12)      \
+  {X1, X2, X10,         X11,         OPT_##ID, opt::Option::KIND##Class,       \
+   X9, X8, OPT_##GROUP, OPT_##ALIAS, X7,       X12},
 #include "Options.inc"
 #undef OPTION
 };
@@ -54,8 +53,6 @@ ELFOptTable::ELFOptTable() : OptTable(OptInfo) {}
 
 // Parse -color-diagnostics={auto,always,never} or -no-color-diagnostics.
 static bool getColorDiagnostics(opt::InputArgList &Args) {
-  bool Default = (ErrorOS == &errs() && Process::StandardErrHasColors());
-
   auto *Arg = Args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
                               OPT_no_color_diagnostics);
   if (!Arg)
@@ -67,7 +64,7 @@ static bool getColorDiagnostics(opt::InputArgList &Args) {
 
   StringRef S = Arg->getValue();
   if (S == "auto")
-    return Default;
+    return ErrorOS->has_colors();
   if (S == "always")
     return true;
   if (S != "never")
@@ -129,10 +126,11 @@ void elf::printHelp(const char *Argv0) {
   // 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-powerpc "
-         << "elf32-tradbigmips elf32-tradlittlemips elf32-x86-64 "
-         << "elf64-amdgpu elf64-littleaarch64 elf64-powerpc "
-         << "elf64-tradbigmips elf64-tradlittlemips elf64-x86-64\n";
+         << "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";
 }
 
 // Reconstructs command line arguments so that so that you can re-run
@@ -149,6 +147,13 @@ std::string elf::createResponseFile(const opt::InputArgList &Args) {
     case OPT_INPUT:
       OS << quote(rewritePath(Arg->getValue())) << "\n";
       break;
+    case OPT_o:
+      // If -o path contains directories, "lld @response.txt" will likely
+      // fail because the archive we are creating doesn't contain empty
+      // directories for the output path (-o doesn't create directories).
+      // Strip directories to prevent the issue.
+      OS << "-o " << quote(sys::path::filename(Arg->getValue())) << "\n";
+      break;
     case OPT_L:
     case OPT_dynamic_list:
     case OPT_rpath:
diff --git a/gnu/llvm/tools/lld/ELF/Options.td b/gnu/llvm/tools/lld/ELF/Options.td
index 77ed4c7e466..1400a206bdf 100644
--- a/gnu/llvm/tools/lld/ELF/Options.td
+++ b/gnu/llvm/tools/lld/ELF/Options.td
@@ -22,6 +22,11 @@ def build_id: F<"build-id">, HelpText<"Generate build ID note">;
 
 def build_id_eq: J<"build-id=">, HelpText<"Generate build ID note">;
 
+def compress_debug_sections : J<"compress-debug-sections=">,
+  HelpText<"Compress DWARF debug sections">;
+
+def defsym: J<"defsym=">, HelpText<"Define a symbol alias">;
+
 def L: JoinedOrSeparate<["-"], "L">, MetaVarName<"<dir>">,
   HelpText<"Add a directory to the library search path">;
 
@@ -48,6 +53,8 @@ def color_diagnostics_eq: J<"color-diagnostics=">,
 def define_common: F<"define-common">,
   HelpText<"Assign space to common symbols">;
 
+def demangle: F<"demangle">, HelpText<"Demangle symbol names">;
+
 def disable_new_dtags: F<"disable-new-dtags">,
   HelpText<"Disable new dynamic tags">;
 
@@ -68,6 +75,8 @@ def dynamic_list: S<"dynamic-list">,
 def eh_frame_hdr: F<"eh-frame-hdr">,
   HelpText<"Request creation of .eh_frame_hdr section and PT_GNU_EH_FRAME segment header">;
 
+def emit_relocs: F<"emit-relocs">, HelpText<"Generate relocations in output">;
+
 def enable_new_dtags: F<"enable-new-dtags">,
   HelpText<"Enable new dynamic tags">;
 
@@ -80,6 +89,12 @@ def entry: S<"entry">, MetaVarName<"<entry>">,
 def error_limit: S<"error-limit">,
   HelpText<"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">;
+
+def exclude_libs: S<"exclude-libs">,
+  HelpText<"Exclude static libraries from automatic export">;
+
 def export_dynamic: F<"export-dynamic">,
   HelpText<"Put symbols in the dynamic symbol table">;
 
@@ -89,6 +104,8 @@ def export_dynamic_symbol: S<"export-dynamic-symbol">,
 def fatal_warnings: F<"fatal-warnings">,
   HelpText<"Treat warnings as errors">;
 
+def filter: J<"filter=">, HelpText<"Set DT_FILTER field to the specified name">;
+
 def fini: S<"fini">, MetaVarName<"<symbol>">,
   HelpText<"Specify a finalizer function">;
 
@@ -109,7 +126,9 @@ def hash_style: S<"hash-style">,
 
 def help: F<"help">, HelpText<"Print option help">;
 
-def icf: F<"icf=all">, HelpText<"Enable identical code folding">;
+def icf_all: F<"icf=all">, HelpText<"Enable identical code folding">;
+
+def icf_none: F<"icf=none">, HelpText<"Disable identical code folding">;
 
 def image_base : J<"image-base=">, HelpText<"Set the base address">;
 
@@ -124,6 +143,8 @@ def lto_O: J<"lto-O">, MetaVarName<"<opt-level>">,
 
 def m: JoinedOrSeparate<["-"], "m">, HelpText<"Set target emulation">;
 
+def Map: JS<"Map">, HelpText<"Print a link map to the specified file">;
+
 def nostdlib: F<"nostdlib">,
   HelpText<"Only search directories specified on the command line">;
 
@@ -139,6 +160,12 @@ def no_define_common: F<"no-define-common">,
 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_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">;
 
@@ -170,7 +197,7 @@ def o: JoinedOrSeparate<["-"], "o">, MetaVarName<"<path>">,
 def oformat: Separate<["--"], "oformat">, MetaVarName<"<format>">,
   HelpText<"Specify the binary format for the output object file">;
 
-def omagic: F<"omagic">, MetaVarName<"<magic>">,
+def omagic: Flag<["--"], "omagic">, MetaVarName<"<magic>">,
   HelpText<"Set the text and data sections to be readable and writable">;
 
 def pie: F<"pie">, HelpText<"Create a position independent executable">;
@@ -178,6 +205,9 @@ def pie: F<"pie">, HelpText<"Create a position independent executable">;
 def print_gc_sections: F<"print-gc-sections">,
   HelpText<"List removed unused sections">;
 
+def print_map: F<"print-map">,
+  HelpText<"Print a link map to the standard output">;
+
 def reproduce: S<"reproduce">,
   HelpText<"Dump linker invocation and input files for debugging">;
 
@@ -221,7 +251,7 @@ def threads: F<"threads">, HelpText<"Run the linker multi-threaded">;
 
 def trace: F<"trace">, HelpText<"Print the names of the input files">;
 
-def trace_symbol : J<"trace-symbol=">, HelpText<"Trace references to symbols">;
+def trace_symbol : S<"trace-symbol">, HelpText<"Trace references to symbols">;
 
 def undefined: S<"undefined">,
   HelpText<"Force undefined symbol during linking">;
@@ -244,6 +274,9 @@ def version_script: S<"version-script">,
 def warn_common: F<"warn-common">,
   HelpText<"Warn about duplicate common symbols">;
 
+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">;
 
@@ -264,25 +297,32 @@ def alias_L__library_path: J<"library-path=">, Alias<L>;
 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_defsym: S<"defsym">, Alias<defsym>;
 def alias_discard_all_x: Flag<["-"], "x">, Alias<discard_all>;
 def alias_discard_locals_X: Flag<["-"], "X">, Alias<discard_locals>;
 def alias_dynamic_list: J<"dynamic-list=">, Alias<dynamic_list>;
+def alias_emit_relocs: Flag<["-"], "q">, Alias<emit_relocs>;
 def alias_entry_e: JoinedOrSeparate<["-"], "e">, Alias<entry>;
 def alias_entry_entry: J<"entry=">, Alias<entry>;
 def alias_error_limit: J<"error-limit=">, Alias<error_limit>;
+def alias_exclude_libs: J<"exclude-libs=">, Alias<exclude_libs>;
 def alias_export_dynamic_E: Flag<["-"], "E">, Alias<export_dynamic>;
 def alias_export_dynamic_symbol: J<"export-dynamic-symbol=">,
   Alias<export_dynamic_symbol>;
+def alias_filter: Separate<["-"], "F">, Alias<filter>;
 def alias_fini_fini: J<"fini=">, Alias<fini>;
 def alias_format_b: S<"b">, Alias<format>;
 def alias_hash_style_hash_style: J<"hash-style=">, Alias<hash_style>;
 def alias_init_init: J<"init=">, Alias<init>;
 def alias_l__library: J<"library=">, Alias<l>;
+def alias_Map_eq: J<"Map=">, Alias<Map>;
 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_reproduce_eq: J<"reproduce=">, Alias<reproduce>;
 def alias_retain_symbols_file: S<"retain-symbols-file">, Alias<retain_symbols_file>;
 def alias_rpath_R: JoinedOrSeparate<["-"], "R">, Alias<rpath>;
 def alias_rpath_rpath: J<"rpath=">, Alias<rpath>;
@@ -297,12 +337,14 @@ def alias_strip_debug_S: Flag<["-"], "S">, Alias<strip_debug>;
 def alias_Tbss: J<"Tbss=">, Alias<Tbss>;
 def alias_Tdata: J<"Tdata=">, Alias<Tdata>;
 def alias_trace: Flag<["-"], "t">, Alias<trace>;
+def trace_trace_symbol_eq : J<"trace-symbol=">, Alias<trace_symbol>;
 def alias_trace_symbol_y : JoinedOrSeparate<["-"], "y">, Alias<trace_symbol>;
 def alias_Ttext: J<"Ttext=">, Alias<Ttext>;
 def alias_Ttext_segment: S<"Ttext-segment">, Alias<Ttext>;
 def alias_Ttext_segment_eq: J<"Ttext-segment=">, Alias<Ttext>;
 def alias_undefined_eq: J<"undefined=">, Alias<undefined>;
 def alias_undefined_u: JoinedOrSeparate<["-"], "u">, Alias<undefined>;
+def alias_version_script_eq: J<"version-script=">, Alias<version_script>;
 def alias_version_V: Flag<["-"], "V">, Alias<version>;
 def alias_wrap_wrap: J<"wrap=">, Alias<wrap>;
 
@@ -314,6 +356,26 @@ def end_group_paren: Flag<["-"], ")">;
 def start_group: F<"start-group">;
 def start_group_paren: Flag<["-"], "(">;
 
+// 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_newpm_passes: J<"lto-newpm-passes=">,
+  HelpText<"Passes to run during LTO">;
+def lto_partitions: J<"lto-partitions=">,
+  HelpText<"Number of LTO codegen partitions">;
+def disable_verify: F<"disable-verify">;
+def mllvm: S<"mllvm">;
+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">;
+def save_temps: F<"save-temps">;
+def thinlto_cache_dir: J<"thinlto-cache-dir=">,
+  HelpText<"Path to ThinLTO cached object file directory">;
+def thinlto_cache_policy: S<"thinlto-cache-policy">,
+  HelpText<"Pruning policy for the ThinLTO cache">;
+def thinlto_jobs: J<"thinlto-jobs=">, HelpText<"Number of ThinLTO jobs">;
+
 // 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
@@ -329,17 +391,13 @@ def plugin_opt_eq: J<"plugin-opt=">;
 // Options listed below are silently ignored for now for compatibility.
 def allow_shlib_undefined: F<"allow-shlib-undefined">;
 def cref: Flag<["--"], "cref">;
-def demangle: F<"demangle">;
 def detect_odr_violations: F<"detect-odr-violations">;
 def g: Flag<["-"], "g">;
-def M: Flag<["-"], "M">;
-def Map: JS<"Map">;
 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">,
   Alias<no_add_needed>;
-def no_dynamic_linker: F<"no-dynamic-linker">;
-def no_fatal_warnings: F<"no-fatal-warnings">;
+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">;
@@ -354,19 +412,3 @@ def EL : F<"EL">;
 def G: JoinedOrSeparate<["-"], "G">;
 def Qy : F<"Qy">;
 
-// Aliases for ignored options
-def alias_Map_eq: J<"Map=">, Alias<Map>;
-def alias_version_script_version_script: J<"version-script=">,
-  Alias<version_script>;
-
-// 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_newpm_passes: J<"lto-newpm-passes=">,
-  HelpText<"Passes to run during LTO">;
-def lto_partitions: J<"lto-partitions=">,
-  HelpText<"Number of LTO codegen partitions">;
-def disable_verify: F<"disable-verify">;
-def mllvm: S<"mllvm">;
-def save_temps: F<"save-temps">;
-def thinlto_jobs: J<"thinlto-jobs=">, HelpText<"Number of ThinLTO jobs">;
diff --git a/gnu/llvm/tools/lld/ELF/OutputSections.cpp b/gnu/llvm/tools/lld/ELF/OutputSections.cpp
index edcc0f186b3..abe54816586 100644
--- a/gnu/llvm/tools/lld/ELF/OutputSections.cpp
+++ b/gnu/llvm/tools/lld/ELF/OutputSections.cpp
@@ -9,7 +9,6 @@
 
 #include "OutputSections.h"
 #include "Config.h"
-#include "EhFrame.h"
 #include "LinkerScript.h"
 #include "Memory.h"
 #include "Strings.h"
@@ -17,7 +16,7 @@
 #include "SyntheticSections.h"
 #include "Target.h"
 #include "Threads.h"
-#include "llvm/Support/Dwarf.h"
+#include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/Support/MD5.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/SHA1.h"
@@ -31,15 +30,21 @@ using namespace llvm::ELF;
 using namespace lld;
 using namespace lld::elf;
 
-OutputSectionBase::OutputSectionBase(StringRef Name, uint32_t Type,
-                                     uint64_t Flags)
-    : Name(Name) {
-  this->Type = Type;
-  this->Flags = Flags;
-  this->Addralign = 1;
-}
-
-uint32_t OutputSectionBase::getPhdrFlags() const {
+uint8_t Out::First;
+OutputSection *Out::Opd;
+uint8_t *Out::OpdBuf;
+PhdrEntry *Out::TlsPhdr;
+OutputSection *Out::DebugInfo;
+OutputSection *Out::ElfHeader;
+OutputSection *Out::ProgramHeaders;
+OutputSection *Out::PreinitArray;
+OutputSection *Out::InitArray;
+OutputSection *Out::FiniArray;
+
+std::vector<OutputSection *> elf::OutputSections;
+std::vector<OutputSectionCommand *> elf::OutputSectionCommands;
+
+uint32_t OutputSection::getPhdrFlags() const {
   uint32_t Ret = PF_R;
   if (Flags & SHF_WRITE)
     Ret |= PF_W;
@@ -49,9 +54,9 @@ uint32_t OutputSectionBase::getPhdrFlags() const {
 }
 
 template <class ELFT>
-void OutputSectionBase::writeHeaderTo(typename ELFT::Shdr *Shdr) {
+void OutputSection::writeHeaderTo(typename ELFT::Shdr *Shdr) {
   Shdr->sh_entsize = Entsize;
-  Shdr->sh_addralign = Addralign;
+  Shdr->sh_addralign = Alignment;
   Shdr->sh_type = Type;
   Shdr->sh_offset = Offset;
   Shdr->sh_flags = Flags;
@@ -62,490 +67,41 @@ void OutputSectionBase::writeHeaderTo(typename ELFT::Shdr *Shdr) {
   Shdr->sh_name = ShName;
 }
 
-template <class ELFT> static uint64_t getEntsize(uint32_t Type) {
-  switch (Type) {
-  case SHT_RELA:
-    return sizeof(typename ELFT::Rela);
-  case SHT_REL:
-    return sizeof(typename ELFT::Rel);
-  case SHT_MIPS_REGINFO:
-    return sizeof(Elf_Mips_RegInfo<ELFT>);
-  case SHT_MIPS_OPTIONS:
-    return sizeof(Elf_Mips_Options<ELFT>) + sizeof(Elf_Mips_RegInfo<ELFT>);
-  case SHT_MIPS_ABIFLAGS:
-    return sizeof(Elf_Mips_ABIFlags<ELFT>);
-  default:
-    return 0;
-  }
-}
+OutputSection::OutputSection(StringRef Name, uint32_t Type, uint64_t Flags)
+    : SectionBase(Output, Name, Flags, /*Entsize*/ 0, /*Alignment*/ 1, Type,
+                  /*Info*/ 0,
+                  /*Link*/ 0),
+      SectionIndex(INT_MAX) {}
 
-template <class ELFT>
-OutputSection<ELFT>::OutputSection(StringRef Name, uint32_t Type, uintX_t Flags)
-    : OutputSectionBase(Name, Type, Flags) {
-  this->Entsize = getEntsize<ELFT>(Type);
-}
-
-template <typename ELFT>
-static bool compareByFilePosition(InputSection<ELFT> *A,
-                                  InputSection<ELFT> *B) {
-  // Synthetic doesn't have link order dependecy, stable_sort will keep it last
-  if (A->kind() == InputSectionData::Synthetic ||
-      B->kind() == InputSectionData::Synthetic)
-    return false;
-  auto *LA = cast<InputSection<ELFT>>(A->getLinkOrderDep());
-  auto *LB = cast<InputSection<ELFT>>(B->getLinkOrderDep());
-  OutputSectionBase *AOut = LA->OutSec;
-  OutputSectionBase *BOut = LB->OutSec;
-  if (AOut != BOut)
-    return AOut->SectionIndex < BOut->SectionIndex;
-  return LA->OutSecOff < LB->OutSecOff;
+static uint64_t updateOffset(uint64_t Off, InputSection *S) {
+  Off = alignTo(Off, S->Alignment);
+  S->OutSecOff = Off;
+  return Off + S->getSize();
 }
 
-template <class ELFT> void OutputSection<ELFT>::finalize() {
-  if ((this->Flags & SHF_LINK_ORDER) && !this->Sections.empty()) {
-    std::sort(Sections.begin(), Sections.end(), compareByFilePosition<ELFT>);
-    Size = 0;
-    assignOffsets();
-
-    // We must preserve the link order dependency of sections with the
-    // SHF_LINK_ORDER flag. The dependency is indicated by the sh_link field. We
-    // need to translate the InputSection sh_link to the OutputSection sh_link,
-    // all InputSections in the OutputSection have the same dependency.
-    if (auto *D = this->Sections.front()->getLinkOrderDep())
-      this->Link = D->OutSec->SectionIndex;
-  }
-
-  uint32_t Type = this->Type;
-  if (!Config->Relocatable || (Type != SHT_RELA && Type != SHT_REL))
-    return;
-
-  this->Link = In<ELFT>::SymTab->OutSec->SectionIndex;
-  // sh_info for SHT_REL[A] sections should contain the section header index of
-  // the section to which the relocation applies.
-  InputSectionBase<ELFT> *S = Sections[0]->getRelocatedSection();
-  this->Info = S->OutSec->SectionIndex;
-}
-
-template <class ELFT>
-void OutputSection<ELFT>::addSection(InputSectionData *C) {
-  assert(C->Live);
-  auto *S = cast<InputSection<ELFT>>(C);
+void OutputSection::addSection(InputSection *S) {
+  assert(S->Live);
   Sections.push_back(S);
-  S->OutSec = this;
+  S->Parent = this;
   this->updateAlignment(S->Alignment);
-  // Keep sh_entsize value of the input section to be able to perform merging
-  // later during a final linking using the generated relocatable object.
-  if (Config->Relocatable && (S->Flags & SHF_MERGE))
-    this->Entsize = S->Entsize;
-}
-
-// This function is called after we sort input sections
-// and scan relocations to setup sections' offsets.
-template <class ELFT> void OutputSection<ELFT>::assignOffsets() {
-  uintX_t Off = this->Size;
-  for (InputSection<ELFT> *S : Sections) {
-    Off = alignTo(Off, S->Alignment);
-    S->OutSecOff = Off;
-    Off += S->getSize();
-  }
-  this->Size = Off;
-}
-
-template <class ELFT>
-void OutputSection<ELFT>::sort(
-    std::function<int(InputSection<ELFT> *S)> Order) {
-  typedef std::pair<unsigned, InputSection<ELFT> *> Pair;
-  auto Comp = [](const Pair &A, const Pair &B) { return A.first < B.first; };
-
-  std::vector<Pair> V;
-  for (InputSection<ELFT> *S : Sections)
-    V.push_back({Order(S), S});
-  std::stable_sort(V.begin(), V.end(), Comp);
-  Sections.clear();
-  for (Pair &P : V)
-    Sections.push_back(P.second);
-}
-
-// 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
-// because the compiler keeps the original initialization order in a
-// translation unit and we need to respect that.
-// For more detail, read the section of the GCC's manual about init_priority.
-template <class ELFT> void OutputSection<ELFT>::sortInitFini() {
-  // Sort sections by priority.
-  sort([](InputSection<ELFT> *S) { return getPriority(S->Name); });
-}
-
-// Returns true if S matches /Filename.?\.o$/.
-static bool isCrtBeginEnd(StringRef S, StringRef Filename) {
-  if (!S.endswith(".o"))
-    return false;
-  S = S.drop_back(2);
-  if (S.endswith(Filename))
-    return true;
-  return !S.empty() && S.drop_back().endswith(Filename);
-}
-
-static bool isCrtbegin(StringRef S) { return isCrtBeginEnd(S, "crtbegin"); }
-static bool isCrtend(StringRef S) { return isCrtBeginEnd(S, "crtend"); }
-
-// .ctors and .dtors are sorted by this priority from highest to lowest.
-//
-//  1. The section was contained in crtbegin (crtbegin contains
-//     some sentinel value in its .ctors and .dtors so that the runtime
-//     can find the beginning of the sections.)
-//
-//  2. The section has an optional priority value in the form of ".ctors.N"
-//     or ".dtors.N" where N is a number. Unlike .{init,fini}_array,
-//     they are compared as string rather than number.
-//
-//  3. The section is just ".ctors" or ".dtors".
-//
-//  4. The section was contained in crtend, which contains an end marker.
-//
-// In an ideal world, we don't need this function because .init_array and
-// .ctors are duplicate features (and .init_array is newer.) However, there
-// are too many real-world use cases of .ctors, so we had no choice to
-// support that with this rather ad-hoc semantics.
-template <class ELFT>
-static bool compCtors(const InputSection<ELFT> *A,
-                      const InputSection<ELFT> *B) {
-  bool BeginA = isCrtbegin(A->getFile()->getName());
-  bool BeginB = isCrtbegin(B->getFile()->getName());
-  if (BeginA != BeginB)
-    return BeginA;
-  bool EndA = isCrtend(A->getFile()->getName());
-  bool EndB = isCrtend(B->getFile()->getName());
-  if (EndA != EndB)
-    return EndB;
-  StringRef X = A->Name;
-  StringRef Y = B->Name;
-  assert(X.startswith(".ctors") || X.startswith(".dtors"));
-  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;
-}
-
-// Sorts input sections by the special rules for .ctors and .dtors.
-// Unfortunately, the rules are different from the one for .{init,fini}_array.
-// Read the comment above.
-template <class ELFT> void OutputSection<ELFT>::sortCtorsDtors() {
-  std::stable_sort(Sections.begin(), Sections.end(), compCtors<ELFT>);
-}
-
-// Fill [Buf, Buf + Size) with Filler. Filler is written in big
-// endian order. This is used for linker script "=fillexp" command.
-void fill(uint8_t *Buf, size_t Size, uint32_t Filler) {
-  uint8_t V[4];
-  write32be(V, Filler);
-  size_t I = 0;
-  for (; I + 4 < Size; I += 4)
-    memcpy(Buf + I, V, 4);
-  memcpy(Buf + I, V, Size - I);
-}
-
-template <class ELFT> void OutputSection<ELFT>::writeTo(uint8_t *Buf) {
-  Loc = Buf;
-  if (uint32_t Filler = Script<ELFT>::X->getFiller(this->Name))
-    fill(Buf, this->Size, Filler);
-
-  auto Fn = [=](InputSection<ELFT> *IS) { IS->writeTo(Buf); };
-  forEach(Sections.begin(), Sections.end(), Fn);
-
-  // Linker scripts may have BYTE()-family commands with which you
-  // can write arbitrary bytes to the output. Process them if any.
-  Script<ELFT>::X->writeDataBytes(this->Name, Buf);
-}
-
-template <class ELFT>
-EhOutputSection<ELFT>::EhOutputSection()
-    : OutputSectionBase(".eh_frame", SHT_PROGBITS, SHF_ALLOC) {}
-
-// Search for an existing CIE record or create a new one.
-// CIE records from input object files are uniquified by their contents
-// and where their relocations point to.
-template <class ELFT>
-template <class RelTy>
-CieRecord *EhOutputSection<ELFT>::addCie(EhSectionPiece &Piece,
-                                         ArrayRef<RelTy> Rels) {
-  auto *Sec = cast<EhInputSection<ELFT>>(Piece.ID);
-  const endianness E = ELFT::TargetEndianness;
-  if (read32<E>(Piece.data().data() + 4) != 0)
-    fatal(toString(Sec) + ": CIE expected at beginning of .eh_frame");
-
-  SymbolBody *Personality = nullptr;
-  unsigned FirstRelI = Piece.FirstRelocation;
-  if (FirstRelI != (unsigned)-1)
-    Personality = &Sec->getFile()->getRelocTargetSym(Rels[FirstRelI]);
-
-  // Search for an existing CIE by CIE contents/relocation target pair.
-  CieRecord *Cie = &CieMap[{Piece.data(), Personality}];
-
-  // If not found, create a new one.
-  if (Cie->Piece == nullptr) {
-    Cie->Piece = &Piece;
-    Cies.push_back(Cie);
-  }
-  return Cie;
-}
-
-// There is one FDE per function. Returns true if a given FDE
-// points to a live function.
-template <class ELFT>
-template <class RelTy>
-bool EhOutputSection<ELFT>::isFdeLive(EhSectionPiece &Piece,
-                                      ArrayRef<RelTy> Rels) {
-  auto *Sec = cast<EhInputSection<ELFT>>(Piece.ID);
-  unsigned FirstRelI = Piece.FirstRelocation;
-  if (FirstRelI == (unsigned)-1)
-    fatal(toString(Sec) + ": FDE doesn't reference another section");
-  const RelTy &Rel = Rels[FirstRelI];
-  SymbolBody &B = Sec->getFile()->getRelocTargetSym(Rel);
-  auto *D = dyn_cast<DefinedRegular<ELFT>>(&B);
-  if (!D || !D->Section)
-    return false;
-  InputSectionBase<ELFT> *Target = D->Section->Repl;
-  return Target && Target->Live;
-}
-
-// .eh_frame is a sequence of CIE or FDE records. In general, there
-// is one CIE record per input object file which is followed by
-// a list of FDEs. This function searches an existing CIE or create a new
-// one and associates FDEs to the CIE.
-template <class ELFT>
-template <class RelTy>
-void EhOutputSection<ELFT>::addSectionAux(EhInputSection<ELFT> *Sec,
-                                          ArrayRef<RelTy> Rels) {
-  const endianness E = ELFT::TargetEndianness;
-
-  DenseMap<size_t, CieRecord *> OffsetToCie;
-  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<E>(Piece.data().data() + 4);
-    if (ID == 0) {
-      OffsetToCie[Offset] = addCie(Piece, Rels);
-      continue;
-    }
-
-    uint32_t CieOffset = Offset + 4 - ID;
-    CieRecord *Cie = OffsetToCie[CieOffset];
-    if (!Cie)
-      fatal(toString(Sec) + ": invalid CIE reference");
-
-    if (!isFdeLive(Piece, Rels))
-      continue;
-    Cie->FdePieces.push_back(&Piece);
-    NumFdes++;
-  }
-}
-
-template <class ELFT>
-void EhOutputSection<ELFT>::addSection(InputSectionData *C) {
-  auto *Sec = cast<EhInputSection<ELFT>>(C);
-  Sec->OutSec = this;
-  this->updateAlignment(Sec->Alignment);
-  Sections.push_back(Sec);
-
-  // .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();
-  if (Sec->Pieces.empty())
-    return;
-
-  if (Sec->NumRelocations) {
-    if (Sec->AreRelocsRela)
-      addSectionAux(Sec, Sec->relas());
-    else
-      addSectionAux(Sec, Sec->rels());
-    return;
-  }
-  addSectionAux(Sec, makeArrayRef<Elf_Rela>(nullptr, nullptr));
-}
-
-template <class ELFT>
-static void writeCieFde(uint8_t *Buf, ArrayRef<uint8_t> D) {
-  memcpy(Buf, D.data(), D.size());
 
-  // Fix the size field. -4 since size does not include the size field itself.
-  const endianness E = ELFT::TargetEndianness;
-  write32<E>(Buf, alignTo(D.size(), sizeof(typename ELFT::uint)) - 4);
-}
-
-template <class ELFT> void EhOutputSection<ELFT>::finalize() {
-  if (this->Size)
-    return; // Already finalized.
-
-  size_t Off = 0;
-  for (CieRecord *Cie : Cies) {
-    Cie->Piece->OutputOff = Off;
-    Off += alignTo(Cie->Piece->size(), sizeof(uintX_t));
-
-    for (EhSectionPiece *Fde : Cie->FdePieces) {
-      Fde->OutputOff = Off;
-      Off += alignTo(Fde->size(), sizeof(uintX_t));
-    }
-  }
-  this->Size = Off + 4;
-}
-
-template <class ELFT> static uint64_t readFdeAddr(uint8_t *Buf, int Size) {
-  const endianness E = ELFT::TargetEndianness;
-  switch (Size) {
-  case DW_EH_PE_udata2:
-    return read16<E>(Buf);
-  case DW_EH_PE_udata4:
-    return read32<E>(Buf);
-  case DW_EH_PE_udata8:
-    return read64<E>(Buf);
-  case DW_EH_PE_absptr:
-    if (ELFT::Is64Bits)
-      return read64<E>(Buf);
-    return read32<E>(Buf);
-  }
-  fatal("unknown FDE size encoding");
-}
-
-// Returns the VA to which a given FDE (on a mmap'ed buffer) is applied to.
-// We need it to create .eh_frame_hdr section.
-template <class ELFT>
-typename ELFT::uint EhOutputSection<ELFT>::getFdePc(uint8_t *Buf, size_t FdeOff,
-                                                    uint8_t Enc) {
-  // The starting address to which this FDE applies is
-  // stored at FDE + 8 byte.
-  size_t Off = FdeOff + 8;
-  uint64_t Addr = readFdeAddr<ELFT>(Buf + Off, Enc & 0x7);
-  if ((Enc & 0x70) == DW_EH_PE_absptr)
-    return Addr;
-  if ((Enc & 0x70) == DW_EH_PE_pcrel)
-    return Addr + this->Addr + Off;
-  fatal("unknown FDE size relative encoding");
-}
-
-template <class ELFT> void EhOutputSection<ELFT>::writeTo(uint8_t *Buf) {
-  const endianness E = ELFT::TargetEndianness;
-  for (CieRecord *Cie : Cies) {
-    size_t CieOffset = Cie->Piece->OutputOff;
-    writeCieFde<ELFT>(Buf + CieOffset, Cie->Piece->data());
-
-    for (EhSectionPiece *Fde : Cie->FdePieces) {
-      size_t Off = Fde->OutputOff;
-      writeCieFde<ELFT>(Buf + Off, Fde->data());
-
-      // FDE's second word should have the offset to an associated CIE.
-      // Write it.
-      write32<E>(Buf + Off + 4, Off + 4 - CieOffset);
-    }
-  }
-
-  for (EhInputSection<ELFT> *S : Sections)
-    S->relocate(Buf, nullptr);
-
-  // Construct .eh_frame_hdr. .eh_frame_hdr is a binary search table
-  // to get a FDE from an address to which FDE is applied. So here
-  // we obtain two addresses and pass them to EhFrameHdr object.
-  if (In<ELFT>::EhFrameHdr) {
-    for (CieRecord *Cie : Cies) {
-      uint8_t Enc = getFdeEncoding<ELFT>(Cie->Piece);
-      for (SectionPiece *Fde : Cie->FdePieces) {
-        uintX_t Pc = getFdePc(Buf, Fde->OutputOff, Enc);
-        uintX_t FdeVA = this->Addr + Fde->OutputOff;
-        In<ELFT>::EhFrameHdr->addFde(Pc, FdeVA);
-      }
-    }
-  }
-}
-
-template <class ELFT>
-MergeOutputSection<ELFT>::MergeOutputSection(StringRef Name, uint32_t Type,
-                                             uintX_t Flags, uintX_t Alignment)
-    : OutputSectionBase(Name, Type, Flags),
-      Builder(StringTableBuilder::RAW, Alignment) {}
-
-template <class ELFT> void MergeOutputSection<ELFT>::writeTo(uint8_t *Buf) {
-  Builder.write(Buf);
-}
-
-template <class ELFT>
-void MergeOutputSection<ELFT>::addSection(InputSectionData *C) {
-  auto *Sec = cast<MergeInputSection<ELFT>>(C);
-  Sec->OutSec = this;
-  this->updateAlignment(Sec->Alignment);
-  this->Entsize = Sec->Entsize;
-  Sections.push_back(Sec);
-}
-
-template <class ELFT> bool MergeOutputSection<ELFT>::shouldTailMerge() const {
-  return (this->Flags & SHF_STRINGS) && Config->Optimize >= 2;
-}
-
-template <class ELFT> void MergeOutputSection<ELFT>::finalizeTailMerge() {
-  // Add all string pieces to the string table builder to create section
-  // contents.
-  for (MergeInputSection<ELFT> *Sec : Sections)
-    for (size_t I = 0, E = Sec->Pieces.size(); I != E; ++I)
-      if (Sec->Pieces[I].Live)
-        Builder.add(Sec->getData(I));
-
-  // Fix the string table content. After this, the contents will never change.
-  Builder.finalize();
-  this->Size = Builder.getSize();
-
-  // finalize() fixed tail-optimized strings, so we can now get
-  // offsets of strings. Get an offset for each string and save it
-  // to a corresponding StringPiece for easy access.
-  for (MergeInputSection<ELFT> *Sec : Sections)
-    for (size_t I = 0, E = Sec->Pieces.size(); I != E; ++I)
-      if (Sec->Pieces[I].Live)
-        Sec->Pieces[I].OutputOff = Builder.getOffset(Sec->getData(I));
-}
-
-template <class ELFT> void MergeOutputSection<ELFT>::finalizeNoTailMerge() {
-  // Add all string pieces to the string table builder to create section
-  // contents. Because we are not tail-optimizing, offsets of strings are
-  // fixed when they are added to the builder (string table builder contains
-  // a hash table from strings to offsets).
-  for (MergeInputSection<ELFT> *Sec : Sections)
-    for (size_t I = 0, E = Sec->Pieces.size(); I != E; ++I)
-      if (Sec->Pieces[I].Live)
-        Sec->Pieces[I].OutputOff = Builder.add(Sec->getData(I));
-
-  Builder.finalizeInOrder();
-  this->Size = Builder.getSize();
-}
+  // The actual offsets will be computed by assignAddresses. For now, use
+  // crude approximation so that it is at least easy for other code to know the
+  // section order. It is also used to calculate the output section size early
+  // for compressed debug sections.
+  this->Size = updateOffset(Size, S);
 
-template <class ELFT> void MergeOutputSection<ELFT>::finalize() {
-  if (shouldTailMerge())
-    finalizeTailMerge();
-  else
-    finalizeNoTailMerge();
+  // If this section contains a table of fixed-size entries, sh_entsize
+  // holds the element size. Consequently, if this contains two or more
+  // input sections, all of them must have the same sh_entsize. However,
+  // you can put different types of input sections into one output
+  // sectin by using linker scripts. I don't know what to do here.
+  // Probably we sholuld handle that as an error. But for now we just
+  // pick the largest sh_entsize.
+  this->Entsize = std::max(this->Entsize, S->Entsize);
 }
 
-template <class ELFT>
-static typename ELFT::uint getOutFlags(InputSectionBase<ELFT> *S) {
-  return S->Flags & ~SHF_GROUP & ~SHF_COMPRESSED;
-}
-
-namespace llvm {
-template <> struct DenseMapInfo<lld::elf::SectionKey> {
-  static lld::elf::SectionKey getEmptyKey();
-  static lld::elf::SectionKey getTombstoneKey();
-  static unsigned getHashValue(const lld::elf::SectionKey &Val);
-  static bool isEqual(const lld::elf::SectionKey &LHS,
-                      const lld::elf::SectionKey &RHS);
-};
-}
-
-template <class ELFT>
-static SectionKey createKey(InputSectionBase<ELFT> *C, StringRef OutsecName) {
+static SectionKey createKey(InputSectionBase *C, StringRef OutsecName) {
   //  The ELF spec just says
   // ----------------------------------------------------------------
   // In the first phase, input sections that match in name, type and
@@ -588,81 +144,109 @@ static SectionKey createKey(InputSectionBase<ELFT> *C, StringRef OutsecName) {
   //
   // Given the above issues, we instead merge sections by name and error on
   // incompatible types and flags.
-  //
-  // The exception being SHF_MERGE, where we create different output sections
-  // for each alignment. This makes each output section simple. In case of
-  // relocatable object generation we do not try to perform merging and treat
-  // SHF_MERGE sections as regular ones, but also create different output
-  // sections for them to allow merging at final linking stage.
-  //
-  // Fortunately, creating symbols in the middle of a merge section is not
-  // supported by bfd or gold, so the SHF_MERGE exception should not cause
-  // problems with most linker scripts.
 
-  typedef typename ELFT::uint uintX_t;
-  uintX_t Flags = C->Flags & (SHF_MERGE | SHF_STRINGS);
-
-  uintX_t Alignment = 0;
-  if (isa<MergeInputSection<ELFT>>(C) ||
-      (Config->Relocatable && (C->Flags & SHF_MERGE)))
-    Alignment = std::max<uintX_t>(C->Alignment, C->Entsize);
+  uint32_t Alignment = 0;
+  uint64_t Flags = 0;
+  if (Config->Relocatable && (C->Flags & SHF_MERGE)) {
+    Alignment = std::max<uint64_t>(C->Alignment, C->Entsize);
+    Flags = C->Flags & (SHF_MERGE | SHF_STRINGS);
+  }
 
   return SectionKey{OutsecName, Flags, Alignment};
 }
 
-template <class ELFT> OutputSectionFactory<ELFT>::OutputSectionFactory() {}
+OutputSectionFactory::OutputSectionFactory() {}
 
-template <class ELFT> OutputSectionFactory<ELFT>::~OutputSectionFactory() {}
+static uint64_t getIncompatibleFlags(uint64_t Flags) {
+  return Flags & (SHF_ALLOC | SHF_TLS);
+}
 
-template <class ELFT>
-std::pair<OutputSectionBase *, bool>
-OutputSectionFactory<ELFT>::create(InputSectionBase<ELFT> *C,
-                                   StringRef OutsecName) {
-  SectionKey Key = createKey(C, OutsecName);
-  return create(Key, C);
+// We allow sections of types listed below to merged into a
+// single progbits section. This is typically done by linker
+// scripts. Merging nobits and progbits will force disk space
+// to be allocated for nobits sections. Other ones don't require
+// any special treatment on top of progbits, so there doesn't
+// seem to be a harm in merging them.
+static bool canMergeToProgbits(unsigned Type) {
+  return Type == SHT_NOBITS || Type == SHT_PROGBITS || Type == SHT_INIT_ARRAY ||
+         Type == SHT_PREINIT_ARRAY || Type == SHT_FINI_ARRAY ||
+         Type == SHT_NOTE;
 }
 
-static uint64_t getIncompatibleFlags(uint64_t Flags) {
-  return Flags & (SHF_ALLOC | SHF_TLS);
+void elf::reportDiscarded(InputSectionBase *IS) {
+  if (!Config->PrintGcSections)
+    return;
+  message("removing unused section from '" + IS->Name + "' in file '" +
+          IS->File->getName() + "'");
+}
+
+void OutputSectionFactory::addInputSec(InputSectionBase *IS,
+                                       StringRef OutsecName) {
+  // Sections with the SHT_GROUP attribute reach here only when the - r option
+  // is given. Such sections define "section groups", and InputFiles.cpp has
+  // dedup'ed section groups by their signatures. For the -r, we want to pass
+  // through all SHT_GROUP sections without merging them because merging them
+  // creates broken section contents.
+  if (IS->Type == SHT_GROUP) {
+    OutputSection *Out = nullptr;
+    addInputSec(IS, OutsecName, Out);
+    return;
+  }
+
+  // Imagine .zed : { *(.foo) *(.bar) } script. Both foo and bar may have
+  // relocation sections .rela.foo and .rela.bar for example. Most tools do
+  // not allow multiple REL[A] sections for output section. Hence we
+  // should combine these relocation sections into single output.
+  // We skip synthetic sections because it can be .rela.dyn/.rela.plt or any
+  // other REL[A] sections created by linker itself.
+  if (!isa<SyntheticSection>(IS) &&
+      (IS->Type == SHT_REL || IS->Type == SHT_RELA)) {
+    auto *Sec = cast<InputSection>(IS);
+    OutputSection *Out = Sec->getRelocatedSection()->getOutputSection();
+    addInputSec(IS, OutsecName, Out->RelocationSection);
+    return;
+  }
+
+  SectionKey Key = createKey(IS, OutsecName);
+  OutputSection *&Sec = Map[Key];
+  addInputSec(IS, OutsecName, Sec);
 }
 
-template <class ELFT>
-std::pair<OutputSectionBase *, bool>
-OutputSectionFactory<ELFT>::create(const SectionKey &Key,
-                                   InputSectionBase<ELFT> *C) {
-  uintX_t Flags = getOutFlags(C);
-  OutputSectionBase *&Sec = Map[Key];
-  if (Sec) {
-    if (getIncompatibleFlags(Sec->Flags) != getIncompatibleFlags(C->Flags))
-      error("Section has flags incompatible with others with the same name " +
-            toString(C));
-    // Convert notbits to progbits if they are mixed. This happens is some
-    // linker scripts.
-    if (Sec->Type == SHT_NOBITS && C->Type == SHT_PROGBITS)
-      Sec->Type = SHT_PROGBITS;
-    if (Sec->Type != C->Type &&
-        !(Sec->Type == SHT_PROGBITS && C->Type == SHT_NOBITS))
-      error("Section has different type from others with the same name " +
-            toString(C));
-    Sec->Flags |= Flags;
-    return {Sec, false};
+void OutputSectionFactory::addInputSec(InputSectionBase *IS,
+                                       StringRef OutsecName,
+                                       OutputSection *&Sec) {
+  if (!IS->Live) {
+    reportDiscarded(IS);
+    return;
   }
 
-  uint32_t Type = C->Type;
-  switch (C->kind()) {
-  case InputSectionBase<ELFT>::Regular:
-  case InputSectionBase<ELFT>::Synthetic:
-    Sec = make<OutputSection<ELFT>>(Key.Name, Type, Flags);
-    break;
-  case InputSectionBase<ELFT>::EHFrame:
-    return {Out<ELFT>::EhFrame, false};
-  case InputSectionBase<ELFT>::Merge:
-    Sec = make<MergeOutputSection<ELFT>>(Key.Name, Type, Flags, Key.Alignment);
-    break;
+  if (Sec) {
+    if (getIncompatibleFlags(Sec->Flags) != getIncompatibleFlags(IS->Flags))
+      error("incompatible section flags for " + Sec->Name + "\n>>> " +
+            toString(IS) + ": 0x" + utohexstr(IS->Flags) +
+            "\n>>> output section " + Sec->Name + ": 0x" +
+            utohexstr(Sec->Flags));
+    if (Sec->Type != IS->Type) {
+      if (canMergeToProgbits(Sec->Type) && canMergeToProgbits(IS->Type))
+        Sec->Type = SHT_PROGBITS;
+      else
+        error("section type mismatch for " + IS->Name + "\n>>> " +
+              toString(IS) + ": " +
+              getELFSectionTypeName(Config->EMachine, IS->Type) +
+              "\n>>> output section " + Sec->Name + ": " +
+              getELFSectionTypeName(Config->EMachine, Sec->Type));
+    }
+    Sec->Flags |= IS->Flags;
+  } else {
+    Sec = make<OutputSection>(OutsecName, IS->Type, IS->Flags);
+    OutputSections.push_back(Sec);
   }
-  return {Sec, true};
+
+  Sec->addSection(cast<InputSection>(IS));
 }
 
+OutputSectionFactory::~OutputSectionFactory() {}
+
 SectionKey DenseMapInfo<SectionKey>::getEmptyKey() {
   return SectionKey{DenseMapInfo<StringRef>::getEmptyKey(), 0, 0};
 }
@@ -681,32 +265,13 @@ bool DenseMapInfo<SectionKey>::isEqual(const SectionKey &LHS,
          LHS.Flags == RHS.Flags && LHS.Alignment == RHS.Alignment;
 }
 
-namespace lld {
-namespace elf {
-
-template void OutputSectionBase::writeHeaderTo<ELF32LE>(ELF32LE::Shdr *Shdr);
-template void OutputSectionBase::writeHeaderTo<ELF32BE>(ELF32BE::Shdr *Shdr);
-template void OutputSectionBase::writeHeaderTo<ELF64LE>(ELF64LE::Shdr *Shdr);
-template void OutputSectionBase::writeHeaderTo<ELF64BE>(ELF64BE::Shdr *Shdr);
-
-template class OutputSection<ELF32LE>;
-template class OutputSection<ELF32BE>;
-template class OutputSection<ELF64LE>;
-template class OutputSection<ELF64BE>;
-
-template class EhOutputSection<ELF32LE>;
-template class EhOutputSection<ELF32BE>;
-template class EhOutputSection<ELF64LE>;
-template class EhOutputSection<ELF64BE>;
-
-template class MergeOutputSection<ELF32LE>;
-template class MergeOutputSection<ELF32BE>;
-template class MergeOutputSection<ELF64LE>;
-template class MergeOutputSection<ELF64BE>;
-
-template class OutputSectionFactory<ELF32LE>;
-template class OutputSectionFactory<ELF32BE>;
-template class OutputSectionFactory<ELF64LE>;
-template class OutputSectionFactory<ELF64BE>;
-}
+uint64_t elf::getHeaderSize() {
+  if (Config->OFormatBinary)
+    return 0;
+  return Out::ElfHeader->Size + Out::ProgramHeaders->Size;
 }
+
+template void OutputSection::writeHeaderTo<ELF32LE>(ELF32LE::Shdr *Shdr);
+template void OutputSection::writeHeaderTo<ELF32BE>(ELF32BE::Shdr *Shdr);
+template void OutputSection::writeHeaderTo<ELF64LE>(ELF64LE::Shdr *Shdr);
+template void OutputSection::writeHeaderTo<ELF64BE>(ELF64BE::Shdr *Shdr);
diff --git a/gnu/llvm/tools/lld/ELF/SymbolTable.cpp b/gnu/llvm/tools/lld/ELF/SymbolTable.cpp
index deecd8d74f4..b9817ba9d2d 100644
--- a/gnu/llvm/tools/lld/ELF/SymbolTable.cpp
+++ b/gnu/llvm/tools/lld/ELF/SymbolTable.cpp
@@ -52,6 +52,9 @@ template <class ELFT> static bool isCompatible(InputFile *F) {
 
 // Add symbols in File to the symbol table.
 template <class ELFT> void SymbolTable<ELFT>::addFile(InputFile *File) {
+  if (!Config->FirstElf && isa<ELFFileBase<ELFT>>(File))
+    Config->FirstElf = File;
+
   if (!isCompatible<ELFT>(File))
     return;
 
@@ -75,13 +78,13 @@ template <class ELFT> void SymbolTable<ELFT>::addFile(InputFile *File) {
   }
 
   if (Config->Trace)
-    outs() << toString(File) << "\n";
+    message(toString(File));
 
   // .so file
   if (auto *F = dyn_cast<SharedFile<ELFT>>(File)) {
     // DSOs are uniquified not by filename but by soname.
     F->parseSoName();
-    if (ErrorCount || !SoNames.insert(F->getSoName()).second)
+    if (ErrorCount || !SoNames.insert(F->SoName).second)
       return;
     SharedFiles.push_back(F);
     F->parseRest();
@@ -115,7 +118,7 @@ template <class ELFT> void SymbolTable<ELFT>::addCombinedLTOObject() {
   // Compile bitcode files and replace bitcode symbols.
   LTO.reset(new BitcodeCompiler);
   for (BitcodeFile *F : BitcodeFiles)
-    LTO->add<ELFT>(*F);
+    LTO->add(*F);
 
   for (InputFile *File : LTO->compile()) {
     ObjectFile<ELFT> *Obj = cast<ObjectFile<ELFT>>(File);
@@ -126,19 +129,19 @@ template <class ELFT> void SymbolTable<ELFT>::addCombinedLTOObject() {
 }
 
 template <class ELFT>
-DefinedRegular<ELFT> *SymbolTable<ELFT>::addAbsolute(StringRef Name,
-                                                     uint8_t Visibility,
-                                                     uint8_t Binding) {
+DefinedRegular *SymbolTable<ELFT>::addAbsolute(StringRef Name,
+                                               uint8_t Visibility,
+                                               uint8_t Binding) {
   Symbol *Sym =
       addRegular(Name, Visibility, STT_NOTYPE, 0, 0, Binding, nullptr, nullptr);
-  return cast<DefinedRegular<ELFT>>(Sym->body());
+  return cast<DefinedRegular>(Sym->body());
 }
 
 // Add Name as an "ignored" symbol. An ignored symbol is a regular
 // linker-synthesized defined symbol, but is only defined if needed.
 template <class ELFT>
-DefinedRegular<ELFT> *SymbolTable<ELFT>::addIgnored(StringRef Name,
-                                                    uint8_t Visibility) {
+DefinedRegular *SymbolTable<ELFT>::addIgnored(StringRef Name,
+                                              uint8_t Visibility) {
   SymbolBody *S = find(Name);
   if (!S || S->isInCurrentDSO())
     return nullptr;
@@ -159,7 +162,7 @@ template <class ELFT> void SymbolTable<ELFT>::trace(StringRef Name) {
 
 // Rename SYM as __wrap_SYM. The original symbol is preserved as __real_SYM.
 // Used to implement --wrap.
-template <class ELFT> void SymbolTable<ELFT>::wrap(StringRef Name) {
+template <class ELFT> void SymbolTable<ELFT>::addSymbolWrap(StringRef Name) {
   SymbolBody *B = find(Name);
   if (!B)
     return;
@@ -167,11 +170,40 @@ template <class ELFT> void SymbolTable<ELFT>::wrap(StringRef Name) {
   Symbol *Real = addUndefined(Saver.save("__real_" + Name));
   Symbol *Wrap = addUndefined(Saver.save("__wrap_" + Name));
 
-  // We rename symbols by replacing the old symbol's SymbolBody with the new
-  // symbol's SymbolBody. This causes all SymbolBody pointers referring to the
-  // old symbol to instead refer to the new symbol.
-  memcpy(Real->Body.buffer, Sym->Body.buffer, sizeof(Sym->Body));
-  memcpy(Sym->Body.buffer, Wrap->Body.buffer, sizeof(Wrap->Body));
+  // Tell LTO not to eliminate this symbol
+  Wrap->IsUsedInRegularObj = true;
+
+  Config->RenamedSymbols[Real] = {Sym, Real->Binding};
+  Config->RenamedSymbols[Sym] = {Wrap, Sym->Binding};
+}
+
+// Creates alias for symbol. Used to implement --defsym=ALIAS=SYM.
+template <class ELFT>
+void SymbolTable<ELFT>::addSymbolAlias(StringRef Alias, StringRef Name) {
+  SymbolBody *B = find(Name);
+  if (!B) {
+    error("-defsym: undefined symbol: " + Name);
+    return;
+  }
+  Symbol *Sym = B->symbol();
+  Symbol *AliasSym = addUndefined(Alias);
+
+  // Tell LTO not to eliminate this symbol
+  Sym->IsUsedInRegularObj = true;
+  Config->RenamedSymbols[AliasSym] = {Sym, AliasSym->Binding};
+}
+
+// Apply symbol renames created by -wrap and -defsym. The renames are created
+// before LTO in addSymbolWrap() and addSymbolAlias() to have a chance to inform
+// LTO (if LTO is running) not to include these symbols in IPO. Now that the
+// symbols are finalized, we can perform the replacement.
+template <class ELFT> void SymbolTable<ELFT>::applySymbolRenames() {
+  for (auto &KV : Config->RenamedSymbols) {
+    Symbol *Dst = KV.first;
+    Symbol *Src = KV.second.Target;
+    Dst->body()->copy(Src->body());
+    Dst->Binding = KV.second.OriginalBinding;
+  }
 }
 
 static uint8_t getMinVisibility(uint8_t VA, uint8_t VB) {
@@ -185,6 +217,12 @@ static uint8_t getMinVisibility(uint8_t VA, uint8_t VB) {
 // Find an existing symbol or create and insert a new one.
 template <class ELFT>
 std::pair<Symbol *, bool> SymbolTable<ELFT>::insert(StringRef Name) {
+  // <name>@@<version> means the symbol is the default version. In that
+  // case <name>@@<version> will be used to resolve references to <name>.
+  size_t Pos = Name.find("@@");
+  if (Pos != StringRef::npos)
+    Name = Name.take_front(Pos);
+
   auto P = Symtab.insert(
       {CachedHashStringRef(Name), SymIndex((int)SymVector.size(), false)});
   SymIndex &V = P.first->second;
@@ -197,7 +235,7 @@ std::pair<Symbol *, bool> SymbolTable<ELFT>::insert(StringRef Name) {
 
   Symbol *Sym;
   if (IsNew) {
-    Sym = new (BAlloc) Symbol;
+    Sym = make<Symbol>();
     Sym->InVersionScript = false;
     Sym->Binding = STB_WEAK;
     Sym->Visibility = STV_DEFAULT;
@@ -212,13 +250,6 @@ std::pair<Symbol *, bool> SymbolTable<ELFT>::insert(StringRef Name) {
   return {Sym, IsNew};
 }
 
-// Construct a string in the form of "Sym in File1 and File2".
-// Used to construct an error message.
-static std::string conflictMsg(SymbolBody *Existing, InputFile *NewFile) {
-  return "'" + toString(*Existing) + "' in " + toString(Existing->File) +
-         " and " + toString(NewFile);
-}
-
 // Find an existing symbol or create and insert a new one, then apply the given
 // attributes.
 template <class ELFT>
@@ -232,13 +263,19 @@ SymbolTable<ELFT>::insert(StringRef Name, uint8_t Type, uint8_t Visibility,
 
   // Merge in the new symbol's visibility.
   S->Visibility = getMinVisibility(S->Visibility, Visibility);
+
   if (!CanOmitFromDynSym && (Config->Shared || Config->ExportDynamic))
     S->ExportDynamic = true;
+
   if (IsUsedInRegularObj)
     S->IsUsedInRegularObj = true;
+
   if (!WasInserted && S->body()->Type != SymbolBody::UnknownType &&
-      ((Type == STT_TLS) != S->body()->isTls()))
-    error("TLS attribute mismatch for symbol " + conflictMsg(S->body(), File));
+      ((Type == STT_TLS) != S->body()->isTls())) {
+    error("TLS attribute mismatch: " + toString(*S->body()) +
+          "\n>>> defined in " + toString(S->body()->File) +
+          "\n>>> defined in " + toString(File));
+  }
 
   return {S, WasInserted};
 }
@@ -258,18 +295,23 @@ Symbol *SymbolTable<ELFT>::addUndefined(StringRef Name, bool IsLocal,
                                         InputFile *File) {
   Symbol *S;
   bool WasInserted;
+  uint8_t Visibility = getVisibility(StOther);
   std::tie(S, WasInserted) =
-      insert(Name, Type, getVisibility(StOther), CanOmitFromDynSym, File);
-  if (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->body()) && Visibility != STV_DEFAULT)) {
     S->Binding = Binding;
-    replaceBody<Undefined<ELFT>>(S, Name, IsLocal, StOther, Type, File);
+    replaceBody<Undefined>(S, Name, IsLocal, StOther, Type, File);
     return S;
   }
   if (Binding != STB_WEAK) {
-    if (S->body()->isShared() || S->body()->isLazy())
+    SymbolBody *B = S->body();
+    if (B->isShared() || B->isLazy() || B->isUndefined())
       S->Binding = Binding;
-    if (auto *SS = dyn_cast<SharedSymbol<ELFT>>(S->body()))
-      SS->file()->IsUsed = true;
+    if (auto *SS = dyn_cast<SharedSymbol>(B))
+      cast<SharedFile<ELFT>>(SS->File)->IsUsed = true;
   }
   if (auto *L = dyn_cast<Lazy>(S->body())) {
     // An undefined weak will not fetch archive members, but we have to remember
@@ -282,15 +324,36 @@ Symbol *SymbolTable<ELFT>::addUndefined(StringRef Name, bool IsLocal,
   return S;
 }
 
+// Using .symver foo,foo@@VER unfortunately creates two symbols: foo and
+// foo@@VER. We want to effectively ignore foo, so give precedence to
+// foo@@VER.
+// FIXME: If users can transition to using
+// .symver foo,foo@@@VER
+// we can delete this hack.
+static int compareVersion(Symbol *S, StringRef Name) {
+  if (Name.find("@@") != StringRef::npos &&
+      S->body()->getName().find("@@") == StringRef::npos)
+    return 1;
+  if (Name.find("@@") == StringRef::npos &&
+      S->body()->getName().find("@@") != StringRef::npos)
+    return -1;
+  return 0;
+}
+
 // We have a new defined symbol with the specified binding. Return 1 if the new
 // symbol should win, -1 if the new symbol should lose, or 0 if both symbols are
 // strong defined symbols.
-static int compareDefined(Symbol *S, bool WasInserted, uint8_t Binding) {
+static int compareDefined(Symbol *S, bool WasInserted, uint8_t Binding,
+                          StringRef Name) {
   if (WasInserted)
     return 1;
   SymbolBody *Body = S->body();
-  if (Body->isLazy() || !Body->isInCurrentDSO())
+  if (!Body->isInCurrentDSO())
     return 1;
+
+  if (int R = compareVersion(S, Name))
+    return R;
+
   if (Binding == STB_WEAK)
     return -1;
   if (S->isWeak())
@@ -303,8 +366,9 @@ static int compareDefined(Symbol *S, bool WasInserted, uint8_t Binding) {
 // is a conflict. If the new symbol wins, also update the binding.
 template <typename ELFT>
 static int compareDefinedNonCommon(Symbol *S, bool WasInserted, uint8_t Binding,
-                                   bool IsAbsolute, typename ELFT::uint Value) {
-  if (int Cmp = compareDefined(S, WasInserted, Binding)) {
+                                   bool IsAbsolute, typename ELFT::uint Value,
+                                   StringRef Name) {
+  if (int Cmp = compareDefined(S, WasInserted, Binding, Name)) {
     if (Cmp > 0)
       S->Binding = Binding;
     return Cmp;
@@ -315,7 +379,7 @@ static int compareDefinedNonCommon(Symbol *S, bool WasInserted, uint8_t Binding,
     if (Config->WarnCommon)
       warn("common " + S->body()->getName() + " is overridden");
     return 1;
-  } else if (auto *R = dyn_cast<DefinedRegular<ELFT>>(B)) {
+  } else if (auto *R = dyn_cast<DefinedRegular>(B)) {
     if (R->Section == nullptr && Binding == STB_GLOBAL && IsAbsolute &&
         R->Value == Value)
       return -1;
@@ -325,14 +389,14 @@ static int compareDefinedNonCommon(Symbol *S, bool WasInserted, uint8_t Binding,
 
 template <class ELFT>
 Symbol *SymbolTable<ELFT>::addCommon(StringRef N, uint64_t Size,
-                                     uint64_t Alignment, uint8_t Binding,
+                                     uint32_t Alignment, uint8_t Binding,
                                      uint8_t StOther, uint8_t Type,
                                      InputFile *File) {
   Symbol *S;
   bool WasInserted;
   std::tie(S, WasInserted) = insert(N, Type, getVisibility(StOther),
                                     /*CanOmitFromDynSym*/ false, File);
-  int Cmp = compareDefined(S, WasInserted, Binding);
+  int Cmp = compareDefined(S, WasInserted, Binding, N);
   if (Cmp > 0) {
     S->Binding = Binding;
     replaceBody<DefinedCommon>(S, N, Size, Alignment, StOther, Type, File);
@@ -355,73 +419,72 @@ Symbol *SymbolTable<ELFT>::addCommon(StringRef N, uint64_t Size,
   return S;
 }
 
-static void print(const Twine &Msg) {
+static void warnOrError(const Twine &Msg) {
   if (Config->AllowMultipleDefinition)
     warn(Msg);
   else
     error(Msg);
 }
 
-static void reportDuplicate(SymbolBody *Existing, InputFile *NewFile) {
-  print("duplicate symbol " + conflictMsg(Existing, NewFile));
+static void reportDuplicate(SymbolBody *Sym, InputFile *NewFile) {
+  warnOrError("duplicate symbol: " + toString(*Sym) + "\n>>> defined in " +
+              toString(Sym->File) + "\n>>> defined in " + toString(NewFile));
 }
 
 template <class ELFT>
-static void reportDuplicate(SymbolBody *Existing,
-                            InputSectionBase<ELFT> *ErrSec,
+static void reportDuplicate(SymbolBody *Sym, InputSectionBase *ErrSec,
                             typename ELFT::uint ErrOffset) {
-  DefinedRegular<ELFT> *D = dyn_cast<DefinedRegular<ELFT>>(Existing);
+  DefinedRegular *D = dyn_cast<DefinedRegular>(Sym);
   if (!D || !D->Section || !ErrSec) {
-    reportDuplicate(Existing, ErrSec ? ErrSec->getFile() : nullptr);
+    reportDuplicate(Sym, ErrSec ? ErrSec->getFile<ELFT>() : nullptr);
     return;
   }
 
-  std::string OldLoc = D->Section->getLocation(D->Value);
-  std::string NewLoc = ErrSec->getLocation(ErrOffset);
-
-  print(NewLoc + ": duplicate symbol '" + toString(*Existing) + "'");
-  print(OldLoc + ": previous definition was here");
+  // Construct and print an error message in the form of:
+  //
+  //   ld.lld: error: duplicate symbol: foo
+  //   >>> defined at bar.c:30
+  //   >>>            bar.o (/home/alice/src/bar.o)
+  //   >>> defined at baz.c:563
+  //   >>>            baz.o in archive libbaz.a
+  auto *Sec1 = cast<InputSectionBase>(D->Section);
+  std::string Src1 = Sec1->getSrcMsg<ELFT>(D->Value);
+  std::string Obj1 = Sec1->getObjMsg<ELFT>(D->Value);
+  std::string Src2 = ErrSec->getSrcMsg<ELFT>(ErrOffset);
+  std::string Obj2 = ErrSec->getObjMsg<ELFT>(ErrOffset);
+
+  std::string Msg = "duplicate symbol: " + toString(*Sym) + "\n>>> defined at ";
+  if (!Src1.empty())
+    Msg += Src1 + "\n>>>            ";
+  Msg += Obj1 + "\n>>> defined at ";
+  if (!Src2.empty())
+    Msg += Src2 + "\n>>>            ";
+  Msg += Obj2;
+  warnOrError(Msg);
 }
 
 template <typename ELFT>
 Symbol *SymbolTable<ELFT>::addRegular(StringRef Name, uint8_t StOther,
-                                      uint8_t Type, uintX_t Value, uintX_t Size,
-                                      uint8_t Binding,
-                                      InputSectionBase<ELFT> *Section,
-                                      InputFile *File) {
+                                      uint8_t Type, uint64_t Value,
+                                      uint64_t Size, uint8_t Binding,
+                                      SectionBase *Section, InputFile *File) {
   Symbol *S;
   bool WasInserted;
   std::tie(S, WasInserted) = insert(Name, Type, getVisibility(StOther),
                                     /*CanOmitFromDynSym*/ false, File);
   int Cmp = compareDefinedNonCommon<ELFT>(S, WasInserted, Binding,
-                                          Section == nullptr, Value);
+                                          Section == nullptr, Value, Name);
   if (Cmp > 0)
-    replaceBody<DefinedRegular<ELFT>>(S, Name, /*IsLocal=*/false, StOther, Type,
-                                      Value, Size, Section, File);
+    replaceBody<DefinedRegular>(S, Name, /*IsLocal=*/false, StOther, Type,
+                                Value, Size, Section, File);
   else if (Cmp == 0)
-    reportDuplicate(S->body(), Section, Value);
+    reportDuplicate<ELFT>(S->body(),
+                          dyn_cast_or_null<InputSectionBase>(Section), Value);
   return S;
 }
 
 template <typename ELFT>
-Symbol *SymbolTable<ELFT>::addSynthetic(StringRef N,
-                                        const OutputSectionBase *Section,
-                                        uintX_t Value, uint8_t StOther) {
-  Symbol *S;
-  bool WasInserted;
-  std::tie(S, WasInserted) = insert(N, STT_NOTYPE, getVisibility(StOther),
-                                    /*CanOmitFromDynSym*/ false, nullptr);
-  int Cmp = compareDefinedNonCommon<ELFT>(S, WasInserted, STB_GLOBAL,
-                                          /*IsAbsolute*/ false, /*Value*/ 0);
-  if (Cmp > 0)
-    replaceBody<DefinedSynthetic>(S, N, Value, Section);
-  else if (Cmp == 0)
-    reportDuplicate(S->body(), nullptr);
-  return S;
-}
-
-template <typename ELFT>
-void SymbolTable<ELFT>::addShared(SharedFile<ELFT> *F, StringRef Name,
+void SymbolTable<ELFT>::addShared(SharedFile<ELFT> *File, StringRef Name,
                                   const Elf_Sym &Sym,
                                   const typename ELFT::Verdef *Verdef) {
   // DSO symbols do not affect visibility in the output, so we pass STV_DEFAULT
@@ -429,15 +492,21 @@ void SymbolTable<ELFT>::addShared(SharedFile<ELFT> *F, StringRef Name,
   // unchanged.
   Symbol *S;
   bool WasInserted;
-  std::tie(S, WasInserted) =
-      insert(Name, Sym.getType(), STV_DEFAULT, /*CanOmitFromDynSym*/ true, F);
+  std::tie(S, WasInserted) = insert(Name, Sym.getType(), STV_DEFAULT,
+                                    /*CanOmitFromDynSym*/ true, File);
   // Make sure we preempt DSO symbols with default visibility.
   if (Sym.getVisibility() == STV_DEFAULT)
     S->ExportDynamic = true;
-  if (WasInserted || isa<Undefined<ELFT>>(S->body())) {
-    replaceBody<SharedSymbol<ELFT>>(S, F, Name, Sym, Verdef);
+
+  SymbolBody *Body = S->body();
+  // An undefined symbol with non default visibility must be satisfied
+  // in the same DSO.
+  if (WasInserted ||
+      (isa<Undefined>(Body) && Body->getVisibility() == STV_DEFAULT)) {
+    replaceBody<SharedSymbol>(S, File, Name, Sym.st_other, Sym.getType(), &Sym,
+                              Verdef);
     if (!S->isWeak())
-      F->IsUsed = true;
+      File->IsUsed = true;
   }
 }
 
@@ -450,10 +519,10 @@ Symbol *SymbolTable<ELFT>::addBitcode(StringRef Name, uint8_t Binding,
   std::tie(S, WasInserted) =
       insert(Name, Type, getVisibility(StOther), CanOmitFromDynSym, F);
   int Cmp = compareDefinedNonCommon<ELFT>(S, WasInserted, Binding,
-                                          /*IsAbs*/ false, /*Value*/ 0);
+                                          /*IsAbs*/ false, /*Value*/ 0, Name);
   if (Cmp > 0)
-    replaceBody<DefinedRegular<ELFT>>(S, Name, /*IsLocal=*/false, StOther, Type,
-                                      0, 0, nullptr, F);
+    replaceBody<DefinedRegular>(S, Name, /*IsLocal=*/false, StOther, Type, 0, 0,
+                                nullptr, F);
   else if (Cmp == 0)
     reportDuplicate(S->body(), F);
   return S;
@@ -478,18 +547,18 @@ SymbolBody *SymbolTable<ELFT>::findInCurrentDSO(StringRef Name) {
 }
 
 template <class ELFT>
-void SymbolTable<ELFT>::addLazyArchive(ArchiveFile *F,
-                                       const object::Archive::Symbol Sym) {
+Symbol *SymbolTable<ELFT>::addLazyArchive(ArchiveFile *F,
+                                          const object::Archive::Symbol Sym) {
   Symbol *S;
   bool WasInserted;
   StringRef Name = Sym.getName();
   std::tie(S, WasInserted) = insert(Name);
   if (WasInserted) {
     replaceBody<LazyArchive>(S, *F, Sym, SymbolBody::UnknownType);
-    return;
+    return S;
   }
   if (!S->body()->isUndefined())
-    return;
+    return S;
 
   // Weak undefined symbols should not fetch members from archives. If we were
   // to keep old symbol we would not know that an archive member was available
@@ -500,11 +569,12 @@ void SymbolTable<ELFT>::addLazyArchive(ArchiveFile *F,
   // to preserve its type. FIXME: Move the Type field to Symbol.
   if (S->isWeak()) {
     replaceBody<LazyArchive>(S, *F, Sym, S->body()->Type);
-    return;
+    return S;
   }
   std::pair<MemoryBufferRef, uint64_t> MBInfo = F->getMember(&Sym);
   if (!MBInfo.first.getBuffer().empty())
     addFile(createObjectFile(MBInfo.first, F->getName(), MBInfo.second));
+  return S;
 }
 
 template <class ELFT>
@@ -520,13 +590,10 @@ void SymbolTable<ELFT>::addLazyObject(StringRef Name, LazyObjectFile &Obj) {
     return;
 
   // See comment for addLazyArchive above.
-  if (S->isWeak()) {
+  if (S->isWeak())
     replaceBody<LazyObject>(S, Name, Obj, S->body()->Type);
-  } else {
-    MemoryBufferRef MBRef = Obj.getBuffer();
-    if (!MBRef.getBuffer().empty())
-      addFile(createObjectFile(MBRef));
-  }
+  else if (InputFile *F = Obj.fetch())
+    addFile(F);
 }
 
 // Process undefined (-u) flags by loading lazy symbols named by those flags.
@@ -545,11 +612,20 @@ template <class ELFT> void SymbolTable<ELFT>::scanUndefinedFlags() {
 // shared libraries can find them.
 // Except this, we ignore undefined symbols in DSOs.
 template <class ELFT> void SymbolTable<ELFT>::scanShlibUndefined() {
-  for (SharedFile<ELFT> *File : SharedFiles)
-    for (StringRef U : File->getUndefinedSymbols())
-      if (SymbolBody *Sym = find(U))
-        if (Sym->isDefined())
-          Sym->symbol()->ExportDynamic = true;
+  for (SharedFile<ELFT> *File : SharedFiles) {
+    for (StringRef U : File->getUndefinedSymbols()) {
+      SymbolBody *Sym = find(U);
+      if (!Sym || !Sym->isDefined())
+        continue;
+      Sym->symbol()->ExportDynamic = true;
+
+      // 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->symbol()->VersionId = VER_NDX_GLOBAL;
+    }
+  }
 }
 
 // Initialize DemangledSyms with a map from demangled symbols to symbol
@@ -630,7 +706,8 @@ template <class ELFT> void SymbolTable<ELFT>::handleAnonymousVersion() {
 // Set symbol versions to symbols. This function handles patterns
 // containing no wildcard characters.
 template <class ELFT>
-void SymbolTable<ELFT>::assignExactVersion(SymbolVersion Ver, uint16_t VersionId,
+void SymbolTable<ELFT>::assignExactVersion(SymbolVersion Ver,
+                                           uint16_t VersionId,
                                            StringRef VersionName) {
   if (Ver.HasWildcard)
     return;
@@ -646,6 +723,12 @@ void SymbolTable<ELFT>::assignExactVersion(SymbolVersion Ver, uint16_t VersionId
 
   // Assign the version.
   for (SymbolBody *B : Syms) {
+    // Skip symbols containing version info because symbol versions
+    // specified by symbol names take precedence over version scripts.
+    // See parseSymbolVersion().
+    if (B->getName().find('@') != StringRef::npos)
+      continue;
+
     Symbol *Sym = B->symbol();
     if (Sym->InVersionScript)
       warn("duplicate symbol '" + Ver.Name + "' in version script");
@@ -659,12 +742,11 @@ void SymbolTable<ELFT>::assignWildcardVersion(SymbolVersion Ver,
                                               uint16_t VersionId) {
   if (!Ver.HasWildcard)
     return;
-  std::vector<SymbolBody *> Syms = findAllByVersion(Ver);
 
   // Exact matching takes precendence over fuzzy matching,
   // so we set a version to a symbol only if no version has been assigned
   // to the symbol. This behavior is compatible with GNU.
-  for (SymbolBody *B : Syms)
+  for (SymbolBody *B : findAllByVersion(Ver))
     if (B->symbol()->VersionId == Config->DefaultSymbolVersion)
       B->symbol()->VersionId = VersionId;
 }
@@ -672,19 +754,9 @@ void SymbolTable<ELFT>::assignWildcardVersion(SymbolVersion Ver,
 // This function processes version scripts by updating VersionId
 // member of symbols.
 template <class ELFT> void SymbolTable<ELFT>::scanVersionScript() {
-  // Symbol themselves might know their versions because symbols
-  // can contain versions in the form of <name>@<version>.
-  // Let them parse their names.
-  if (!Config->VersionDefinitions.empty())
-    for (Symbol *Sym : SymVector)
-      Sym->body()->parseSymbolVersion();
-
   // Handle edge cases first.
   handleAnonymousVersion();
 
-  if (Config->VersionDefinitions.empty())
-    return;
-
   // Now we have version definitions, so we need to set version ids to symbols.
   // Each version definition has a glob pattern, and all symbols that match
   // with the pattern get that version.
@@ -702,6 +774,12 @@ template <class ELFT> void SymbolTable<ELFT>::scanVersionScript() {
   for (VersionDefinition &V : llvm::reverse(Config->VersionDefinitions))
     for (SymbolVersion &Ver : V.Globals)
       assignWildcardVersion(Ver, V.Id);
+
+  // Symbol themselves might know their versions because symbols
+  // can contain versions in the form of <name>@<version>.
+  // Let them parse and update their names to exclude version suffix.
+  for (Symbol *Sym : SymVector)
+    Sym->body()->parseSymbolVersion();
 }
 
 template class elf::SymbolTable<ELF32LE>;
diff --git a/gnu/llvm/tools/lld/ELF/Symbols.cpp b/gnu/llvm/tools/lld/ELF/Symbols.cpp
index 43af44ec4b8..c69007e781a 100644
--- a/gnu/llvm/tools/lld/ELF/Symbols.cpp
+++ b/gnu/llvm/tools/lld/ELF/Symbols.cpp
@@ -28,62 +28,90 @@ using namespace llvm::ELF;
 using namespace lld;
 using namespace lld::elf;
 
-template <class ELFT>
-static typename ELFT::uint getSymVA(const SymbolBody &Body,
-                                    typename ELFT::uint &Addend) {
-  typedef typename ELFT::uint uintX_t;
-
+DefinedRegular *ElfSym::Bss;
+DefinedRegular *ElfSym::Etext1;
+DefinedRegular *ElfSym::Etext2;
+DefinedRegular *ElfSym::Edata1;
+DefinedRegular *ElfSym::Edata2;
+DefinedRegular *ElfSym::End1;
+DefinedRegular *ElfSym::End2;
+DefinedRegular *ElfSym::GlobalOffsetTable;
+DefinedRegular *ElfSym::MipsGp;
+DefinedRegular *ElfSym::MipsGpDisp;
+DefinedRegular *ElfSym::MipsLocalGp;
+
+static uint64_t getSymVA(const SymbolBody &Body, int64_t &Addend) {
   switch (Body.kind()) {
-  case SymbolBody::DefinedSyntheticKind: {
-    auto &D = cast<DefinedSynthetic>(Body);
-    const OutputSectionBase *Sec = D.Section;
-    if (!Sec)
-      return D.Value;
-    if (D.Value == uintX_t(-1))
-      return Sec->Addr + Sec->Size;
-    return Sec->Addr + D.Value;
-  }
   case SymbolBody::DefinedRegularKind: {
-    auto &D = cast<DefinedRegular<ELFT>>(Body);
-    InputSectionBase<ELFT> *IS = D.Section;
+    auto &D = cast<DefinedRegular>(Body);
+    SectionBase *IS = D.Section;
+    if (auto *ISB = dyn_cast_or_null<InputSectionBase>(IS))
+      IS = ISB->Repl;
 
     // According to the ELF spec reference to a local symbol from outside
     // the group are not allowed. Unfortunately .eh_frame breaks that rule
     // and must be treated specially. For now we just replace the symbol with
     // 0.
-    if (IS == &InputSection<ELFT>::Discarded)
+    if (IS == &InputSection::Discarded)
       return 0;
 
     // This is an absolute symbol.
     if (!IS)
       return D.Value;
 
-    uintX_t Offset = D.Value;
+    uint64_t Offset = D.Value;
+
+    // An object in an SHF_MERGE section might be referenced via a
+    // section symbol (as a hack for reducing the number of local
+    // symbols).
+    // Depending on the addend, the reference via a section symbol
+    // refers to a different object in the merge section.
+    // Since the objects in the merge section are not necessarily
+    // contiguous in the output, the addend can thus affect the final
+    // VA in a non-linear way.
+    // To make this work, we incorporate the addend into the section
+    // offset (and zero out the addend for later processing) so that
+    // we find the right object in the section.
     if (D.isSection()) {
       Offset += Addend;
       Addend = 0;
     }
-    uintX_t VA = (IS->OutSec ? IS->OutSec->Addr : 0) + IS->getOffset(Offset);
+
+    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.
+    // 2. The offset of the input section within the output section.
+    // 3. The offset within the input section (this addition happens
+    //    inside InputSection::getOffset).
+    //
+    // 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);
+
     if (D.isTls() && !Config->Relocatable) {
-      if (!Out<ELFT>::TlsPhdr)
+      if (!Out::TlsPhdr)
         fatal(toString(D.File) +
-              " has a STT_TLS symbol but doesn't have a PT_TLS section");
-      return VA - Out<ELFT>::TlsPhdr->p_vaddr;
+              " has an STT_TLS symbol but doesn't have an SHF_TLS section");
+      return VA - Out::TlsPhdr->p_vaddr;
     }
     return VA;
   }
   case SymbolBody::DefinedCommonKind:
     if (!Config->DefineCommon)
       return 0;
-    return In<ELFT>::Common->OutSec->Addr + In<ELFT>::Common->OutSecOff +
+    return InX::Common->getParent()->Addr + InX::Common->OutSecOff +
            cast<DefinedCommon>(Body).Offset;
   case SymbolBody::SharedKind: {
-    auto &SS = cast<SharedSymbol<ELFT>>(Body);
-    if (!SS.NeedsCopyOrPltAddr)
-      return 0;
-    if (SS.isFunc())
-      return Body.getPltVA<ELFT>();
-    return SS.getBssSectionForCopy()->Addr + SS.CopyOffset;
+    auto &SS = cast<SharedSymbol>(Body);
+    if (SS.NeedsCopy)
+      return SS.CopyRelSec->getParent()->Addr + SS.CopyRelSec->OutSecOff +
+             SS.CopyRelSecOff;
+    if (SS.NeedsPltAddr)
+      return Body.getPltVA();
+    return 0;
   }
   case SymbolBody::UndefinedKind:
     return 0;
@@ -97,10 +125,9 @@ static typename ELFT::uint getSymVA(const SymbolBody &Body,
 
 SymbolBody::SymbolBody(Kind K, StringRefZ Name, bool IsLocal, uint8_t StOther,
                        uint8_t Type)
-    : SymbolKind(K), NeedsCopyOrPltAddr(false), IsLocal(IsLocal),
+    : SymbolKind(K), NeedsCopy(false), NeedsPltAddr(false), IsLocal(IsLocal),
       IsInGlobalMipsGot(false), Is32BitMipsGot(false), IsInIplt(false),
-      IsInIgot(false), CopyIsInBssRelRo(false), Type(Type), StOther(StOther),
-      Name(Name) {}
+      IsInIgot(false), Type(Type), StOther(StOther), Name(Name) {}
 
 // Returns true if a symbol can be replaced at load-time by a symbol
 // with the same name defined in other ELF executable or DSO.
@@ -112,7 +139,7 @@ bool SymbolBody::isPreemptible() const {
   // symbols with copy relocations (which resolve to .bss) or preempt plt
   // entries (which resolve to that plt entry).
   if (isShared())
-    return !NeedsCopyOrPltAddr;
+    return !NeedsCopy && !NeedsPltAddr;
 
   // That's all that can be preempted in a non-DSO.
   if (!Config->Shared)
@@ -132,65 +159,76 @@ bool SymbolBody::isPreemptible() const {
   return true;
 }
 
-template <class ELFT> bool SymbolBody::hasThunk() const {
-  if (auto *DR = dyn_cast<DefinedRegular<ELFT>>(this))
-    return DR->ThunkData != nullptr;
-  if (auto *S = dyn_cast<SharedSymbol<ELFT>>(this))
-    return S->ThunkData != nullptr;
-  return false;
+// Overwrites all attributes with Other's so that this symbol becomes
+// an alias to Other. This is useful for handling some options such as
+// --wrap.
+void SymbolBody::copy(SymbolBody *Other) {
+  memcpy(symbol()->Body.buffer, Other->symbol()->Body.buffer,
+         sizeof(Symbol::Body));
 }
 
-template <class ELFT>
-typename ELFT::uint SymbolBody::getVA(typename ELFT::uint Addend) const {
-  typename ELFT::uint OutVA = getSymVA<ELFT>(*this, Addend);
+uint64_t SymbolBody::getVA(int64_t Addend) const {
+  uint64_t OutVA = getSymVA(*this, Addend);
   return OutVA + Addend;
 }
 
-template <class ELFT> typename ELFT::uint SymbolBody::getGotVA() const {
-  return In<ELFT>::Got->getVA() + getGotOffset<ELFT>();
+uint64_t SymbolBody::getGotVA() const {
+  return InX::Got->getVA() + getGotOffset();
 }
 
-template <class ELFT> typename ELFT::uint SymbolBody::getGotOffset() const {
+uint64_t SymbolBody::getGotOffset() const {
   return GotIndex * Target->GotEntrySize;
 }
 
-template <class ELFT> typename ELFT::uint SymbolBody::getGotPltVA() const {
+uint64_t SymbolBody::getGotPltVA() const {
   if (this->IsInIgot)
-    return In<ELFT>::IgotPlt->getVA() + getGotPltOffset<ELFT>();
-  return In<ELFT>::GotPlt->getVA() + getGotPltOffset<ELFT>();
+    return InX::IgotPlt->getVA() + getGotPltOffset();
+  return InX::GotPlt->getVA() + getGotPltOffset();
 }
 
-template <class ELFT> typename ELFT::uint SymbolBody::getGotPltOffset() const {
+uint64_t SymbolBody::getGotPltOffset() const {
   return GotPltIndex * Target->GotPltEntrySize;
 }
 
-template <class ELFT> typename ELFT::uint SymbolBody::getPltVA() const {
+uint64_t SymbolBody::getPltVA() const {
   if (this->IsInIplt)
-    return In<ELFT>::Iplt->getVA() + PltIndex * Target->PltEntrySize;
-  return In<ELFT>::Plt->getVA() + Target->PltHeaderSize +
+    return InX::Iplt->getVA() + PltIndex * Target->PltEntrySize;
+  return InX::Plt->getVA() + Target->PltHeaderSize +
          PltIndex * Target->PltEntrySize;
 }
 
-template <class ELFT> typename ELFT::uint SymbolBody::getThunkVA() const {
-  if (const auto *DR = dyn_cast<DefinedRegular<ELFT>>(this))
-    return DR->ThunkData->getVA();
-  if (const auto *S = dyn_cast<SharedSymbol<ELFT>>(this))
-    return S->ThunkData->getVA();
-  if (const auto *S = dyn_cast<Undefined<ELFT>>(this))
-    return S->ThunkData->getVA();
-  fatal("getThunkVA() not supported for Symbol class\n");
-}
-
 template <class ELFT> typename ELFT::uint SymbolBody::getSize() const {
   if (const auto *C = dyn_cast<DefinedCommon>(this))
     return C->Size;
-  if (const auto *DR = dyn_cast<DefinedRegular<ELFT>>(this))
+  if (const auto *DR = dyn_cast<DefinedRegular>(this))
     return DR->Size;
-  if (const auto *S = dyn_cast<SharedSymbol<ELFT>>(this))
-    return S->Sym.st_size;
+  if (const auto *S = dyn_cast<SharedSymbol>(this))
+    return S->getSize<ELFT>();
   return 0;
 }
 
+OutputSection *SymbolBody::getOutputSection() const {
+  if (auto *S = dyn_cast<DefinedRegular>(this)) {
+    if (S->Section)
+      return S->Section->getOutputSection();
+    return nullptr;
+  }
+
+  if (auto *S = dyn_cast<SharedSymbol>(this)) {
+    if (S->NeedsCopy)
+      return S->CopyRelSec->getParent();
+    return nullptr;
+  }
+
+  if (isa<DefinedCommon>(this)) {
+    if (Config->DefineCommon)
+      return InX::Common->getParent();
+    return nullptr;
+  }
+
+  return nullptr;
+}
+
 // If a symbol name contains '@', the characters after that is
 // a symbol version name. This function parses that.
 void SymbolBody::parseSymbolVersion() {
@@ -227,34 +265,36 @@ void SymbolBody::parseSymbolVersion() {
   }
 
   // It is an error if the specified version is not defined.
-  error(toString(File) + ": symbol " + S + " has undefined version " + Verstr);
+  // 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)
+    error(toString(File) + ": symbol " + S + " has undefined version " +
+          Verstr);
 }
 
 Defined::Defined(Kind K, StringRefZ Name, bool IsLocal, uint8_t StOther,
                  uint8_t Type)
     : SymbolBody(K, Name, IsLocal, StOther, Type) {}
 
-template <class ELFT> bool DefinedRegular<ELFT>::isMipsPIC() const {
+template <class ELFT> bool DefinedRegular::isMipsPIC() const {
+  typedef typename ELFT::Ehdr Elf_Ehdr;
   if (!Section || !isFunc())
     return false;
+
+  auto *Sec = cast<InputSectionBase>(Section);
+  const Elf_Ehdr *Hdr = Sec->template getFile<ELFT>()->getObj().getHeader();
   return (this->StOther & STO_MIPS_MIPS16) == STO_MIPS_PIC ||
-         (Section->getFile()->getObj().getHeader()->e_flags & EF_MIPS_PIC);
+         (Hdr->e_flags & EF_MIPS_PIC);
 }
 
-template <typename ELFT>
-Undefined<ELFT>::Undefined(StringRefZ Name, bool IsLocal, uint8_t StOther,
-                           uint8_t Type, InputFile *File)
+Undefined::Undefined(StringRefZ Name, bool IsLocal, uint8_t StOther,
+                     uint8_t Type, InputFile *File)
     : SymbolBody(SymbolBody::UndefinedKind, Name, IsLocal, StOther, Type) {
   this->File = File;
 }
 
-template <typename ELFT>
-OutputSection<ELFT> *SharedSymbol<ELFT>::getBssSectionForCopy() const {
-  assert(needsCopy());
-  return CopyIsInBssRelRo ? Out<ELFT>::BssRelRo : Out<ELFT>::Bss;
-}
-
-DefinedCommon::DefinedCommon(StringRef Name, uint64_t Size, uint64_t Alignment,
+DefinedCommon::DefinedCommon(StringRef Name, uint64_t Size, uint32_t Alignment,
                              uint8_t StOther, uint8_t Type, InputFile *File)
     : Defined(SymbolBody::DefinedCommonKind, Name, /*IsLocal=*/false, StOther,
               Type),
@@ -262,6 +302,17 @@ DefinedCommon::DefinedCommon(StringRef Name, uint64_t Size, uint64_t Alignment,
   this->File = File;
 }
 
+// If a shared symbol is referred via a copy relocation, its alignment
+// becomes part of the ABI. This function returns a symbol alignment.
+// Because symbols don't have alignment attributes, we need to infer that.
+template <class ELFT> uint32_t SharedSymbol::getAlignment() const {
+  auto *File = cast<SharedFile<ELFT>>(this->File);
+  uint32_t SecAlign = File->getSection(getSym<ELFT>())->sh_addralign;
+  uint64_t SymValue = getSym<ELFT>().st_value;
+  uint32_t SymAlign = uint32_t(1) << countTrailingZeros(SymValue);
+  return std::min(SecAlign, SymAlign);
+}
+
 InputFile *Lazy::fetch() {
   if (auto *S = dyn_cast<LazyArchive>(this))
     return S->fetch();
@@ -289,20 +340,14 @@ InputFile *LazyArchive::fetch() {
   return createObjectFile(MBInfo.first, file()->getName(), MBInfo.second);
 }
 
-InputFile *LazyObject::fetch() {
-  MemoryBufferRef MBRef = file()->getBuffer();
-  if (MBRef.getBuffer().empty())
-    return nullptr;
-  return createObjectFile(MBRef);
-}
+InputFile *LazyObject::fetch() { return file()->fetch(); }
 
 uint8_t Symbol::computeBinding() const {
   if (Config->Relocatable)
     return Binding;
   if (Visibility != STV_DEFAULT && Visibility != STV_PROTECTED)
     return STB_LOCAL;
-  const SymbolBody *Body = body();
-  if (VersionId == VER_NDX_LOCAL && Body->isInCurrentDSO())
+  if (VersionId == VER_NDX_LOCAL && body()->isInCurrentDSO())
     return STB_LOCAL;
   if (Config->NoGnuUnique && Binding == STB_GNU_UNIQUE)
     return STB_GLOBAL;
@@ -319,15 +364,15 @@ bool Symbol::includeInDynsym() const {
 // Print out a log message for --trace-symbol.
 void elf::printTraceSymbol(Symbol *Sym) {
   SymbolBody *B = Sym->body();
-  outs() << toString(B->File);
-
+  std::string S;
   if (B->isUndefined())
-    outs() << ": reference to ";
+    S = ": reference to ";
   else if (B->isCommon())
-    outs() << ": common definition of ";
+    S = ": common definition of ";
   else
-    outs() << ": definition of ";
-  outs() << B->getName() << "\n";
+    S = ": definition of ";
+
+  message(toString(B->File) + S + B->getName());
 }
 
 // Returns a symbol for an error message.
@@ -338,62 +383,17 @@ std::string lld::toString(const SymbolBody &B) {
   return B.getName();
 }
 
-template bool SymbolBody::hasThunk<ELF32LE>() const;
-template bool SymbolBody::hasThunk<ELF32BE>() const;
-template bool SymbolBody::hasThunk<ELF64LE>() const;
-template bool SymbolBody::hasThunk<ELF64BE>() const;
-
-template uint32_t SymbolBody::template getVA<ELF32LE>(uint32_t) const;
-template uint32_t SymbolBody::template getVA<ELF32BE>(uint32_t) const;
-template uint64_t SymbolBody::template getVA<ELF64LE>(uint64_t) const;
-template uint64_t SymbolBody::template getVA<ELF64BE>(uint64_t) const;
-
-template uint32_t SymbolBody::template getGotVA<ELF32LE>() const;
-template uint32_t SymbolBody::template getGotVA<ELF32BE>() const;
-template uint64_t SymbolBody::template getGotVA<ELF64LE>() const;
-template uint64_t SymbolBody::template getGotVA<ELF64BE>() const;
-
-template uint32_t SymbolBody::template getGotOffset<ELF32LE>() const;
-template uint32_t SymbolBody::template getGotOffset<ELF32BE>() const;
-template uint64_t SymbolBody::template getGotOffset<ELF64LE>() const;
-template uint64_t SymbolBody::template getGotOffset<ELF64BE>() const;
-
-template uint32_t SymbolBody::template getGotPltVA<ELF32LE>() const;
-template uint32_t SymbolBody::template getGotPltVA<ELF32BE>() const;
-template uint64_t SymbolBody::template getGotPltVA<ELF64LE>() const;
-template uint64_t SymbolBody::template getGotPltVA<ELF64BE>() const;
-
-template uint32_t SymbolBody::template getThunkVA<ELF32LE>() const;
-template uint32_t SymbolBody::template getThunkVA<ELF32BE>() const;
-template uint64_t SymbolBody::template getThunkVA<ELF64LE>() const;
-template uint64_t SymbolBody::template getThunkVA<ELF64BE>() const;
-
-template uint32_t SymbolBody::template getGotPltOffset<ELF32LE>() const;
-template uint32_t SymbolBody::template getGotPltOffset<ELF32BE>() const;
-template uint64_t SymbolBody::template getGotPltOffset<ELF64LE>() const;
-template uint64_t SymbolBody::template getGotPltOffset<ELF64BE>() const;
-
-template uint32_t SymbolBody::template getPltVA<ELF32LE>() const;
-template uint32_t SymbolBody::template getPltVA<ELF32BE>() const;
-template uint64_t SymbolBody::template getPltVA<ELF64LE>() const;
-template uint64_t SymbolBody::template getPltVA<ELF64BE>() const;
-
 template uint32_t SymbolBody::template getSize<ELF32LE>() const;
 template uint32_t SymbolBody::template getSize<ELF32BE>() const;
 template uint64_t SymbolBody::template getSize<ELF64LE>() const;
 template uint64_t SymbolBody::template getSize<ELF64BE>() const;
 
-template class elf::Undefined<ELF32LE>;
-template class elf::Undefined<ELF32BE>;
-template class elf::Undefined<ELF64LE>;
-template class elf::Undefined<ELF64BE>;
-
-template class elf::SharedSymbol<ELF32LE>;
-template class elf::SharedSymbol<ELF32BE>;
-template class elf::SharedSymbol<ELF64LE>;
-template class elf::SharedSymbol<ELF64BE>;
+template bool DefinedRegular::template isMipsPIC<ELF32LE>() const;
+template bool DefinedRegular::template isMipsPIC<ELF32BE>() const;
+template bool DefinedRegular::template isMipsPIC<ELF64LE>() const;
+template bool DefinedRegular::template isMipsPIC<ELF64BE>() const;
 
-template class elf::DefinedRegular<ELF32LE>;
-template class elf::DefinedRegular<ELF32BE>;
-template class elf::DefinedRegular<ELF64LE>;
-template class elf::DefinedRegular<ELF64BE>;
+template uint32_t SharedSymbol::template getAlignment<ELF32LE>() const;
+template uint32_t SharedSymbol::template getAlignment<ELF32BE>() const;
+template uint32_t SharedSymbol::template getAlignment<ELF64LE>() const;
+template uint32_t SharedSymbol::template getAlignment<ELF64BE>() const;
diff --git a/gnu/llvm/tools/lld/ELF/SyntheticSections.cpp b/gnu/llvm/tools/lld/ELF/SyntheticSections.cpp
index d1b6755ab2c..4bbec4ab34b 100644
--- a/gnu/llvm/tools/lld/ELF/SyntheticSections.cpp
+++ b/gnu/llvm/tools/lld/ELF/SyntheticSections.cpp
@@ -27,7 +27,10 @@
 #include "Threads.h"
 #include "Writer.h"
 #include "lld/Config/Version.h"
-#include "llvm/Support/Dwarf.h"
+#include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugPubTable.h"
+#include "llvm/Object/Decompressor.h"
+#include "llvm/Object/ELFObjectFile.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/MD5.h"
 #include "llvm/Support/RandomNumberGenerator.h"
@@ -45,6 +48,12 @@ using namespace llvm::support::endian;
 using namespace lld;
 using namespace lld::elf;
 
+uint64_t SyntheticSection::getVA() const {
+  if (OutputSection *Sec = getParent())
+    return Sec->Addr + OutSecOff;
+  return 0;
+}
+
 template <class ELFT> static std::vector<DefinedCommon *> getCommonSymbols() {
   std::vector<DefinedCommon *> V;
   for (Symbol *S : Symtab<ELFT>::X->getSymbols())
@@ -54,35 +63,24 @@ template <class ELFT> static std::vector<DefinedCommon *> getCommonSymbols() {
 }
 
 // Find all common symbols and allocate space for them.
-template <class ELFT> InputSection<ELFT> *elf::createCommonSection() {
-  auto *Ret = make<InputSection<ELFT>>(SHF_ALLOC | SHF_WRITE, SHT_NOBITS, 1,
-                                       ArrayRef<uint8_t>(), "COMMON");
-  Ret->Live = true;
-
+template <class ELFT> InputSection *elf::createCommonSection() {
   if (!Config->DefineCommon)
-    return Ret;
+    return nullptr;
 
   // Sort the common symbols by alignment as an heuristic to pack them better.
   std::vector<DefinedCommon *> Syms = getCommonSymbols<ELFT>();
+  if (Syms.empty())
+    return nullptr;
+
   std::stable_sort(Syms.begin(), Syms.end(),
                    [](const DefinedCommon *A, const DefinedCommon *B) {
                      return A->Alignment > B->Alignment;
                    });
 
-  // Assign offsets to symbols.
-  size_t Size = 0;
-  size_t Alignment = 1;
-  for (DefinedCommon *Sym : Syms) {
-    Alignment = std::max<size_t>(Alignment, Sym->Alignment);
-    Size = alignTo(Size, Sym->Alignment);
-
-    // Compute symbol offset relative to beginning of input section.
-    Sym->Offset = Size;
-    Size += Sym->Size;
-  }
-  Ret->Alignment = Alignment;
-  Ret->Data = makeArrayRef<uint8_t>(nullptr, Size);
-  return Ret;
+  BssSection *Sec = make<BssSection>("COMMON");
+  for (DefinedCommon *Sym : Syms)
+    Sym->Offset = Sec->reserveSpace(Sym->Size, Sym->Alignment);
+  return Sec;
 }
 
 // Returns an LLD version string.
@@ -100,16 +98,17 @@ static ArrayRef<uint8_t> getVersion() {
 
 // Creates a .comment section containing LLD version info.
 // With this feature, you can identify LLD-generated binaries easily
-// by "objdump -s -j .comment <file>".
+// by "readelf --string-dump .comment <file>".
 // The returned object is a mergeable string section.
-template <class ELFT> MergeInputSection<ELFT> *elf::createCommentSection() {
+template <class ELFT> MergeInputSection *elf::createCommentSection() {
   typename ELFT::Shdr Hdr = {};
   Hdr.sh_flags = SHF_MERGE | SHF_STRINGS;
   Hdr.sh_type = SHT_PROGBITS;
   Hdr.sh_entsize = 1;
   Hdr.sh_addralign = 1;
 
-  auto *Ret = make<MergeInputSection<ELFT>>(/*file=*/nullptr, &Hdr, ".comment");
+  auto *Ret =
+      make<MergeInputSection>((ObjectFile<ELFT> *)nullptr, &Hdr, ".comment");
   Ret->Data = getVersion();
   Ret->splitIntoPieces();
   return Ret;
@@ -118,8 +117,10 @@ template <class ELFT> MergeInputSection<ELFT> *elf::createCommentSection() {
 // .MIPS.abiflags section.
 template <class ELFT>
 MipsAbiFlagsSection<ELFT>::MipsAbiFlagsSection(Elf_Mips_ABIFlags Flags)
-    : SyntheticSection<ELFT>(SHF_ALLOC, SHT_MIPS_ABIFLAGS, 8, ".MIPS.abiflags"),
-      Flags(Flags) {}
+    : SyntheticSection(SHF_ALLOC, SHT_MIPS_ABIFLAGS, 8, ".MIPS.abiflags"),
+      Flags(Flags) {
+  this->Entsize = sizeof(Elf_Mips_ABIFlags);
+}
 
 template <class ELFT> void MipsAbiFlagsSection<ELFT>::writeTo(uint8_t *Buf) {
   memcpy(Buf, &Flags, sizeof(Flags));
@@ -130,13 +131,13 @@ MipsAbiFlagsSection<ELFT> *MipsAbiFlagsSection<ELFT>::create() {
   Elf_Mips_ABIFlags Flags = {};
   bool Create = false;
 
-  for (InputSectionBase<ELFT> *Sec : Symtab<ELFT>::X->Sections) {
-    if (!Sec->Live || Sec->Type != SHT_MIPS_ABIFLAGS)
+  for (InputSectionBase *Sec : InputSections) {
+    if (Sec->Type != SHT_MIPS_ABIFLAGS)
       continue;
     Sec->Live = false;
     Create = true;
 
-    std::string Filename = toString(Sec->getFile());
+    std::string Filename = toString(Sec->getFile<ELFT>());
     const size_t Size = Sec->Data.size();
     // Older version of BFD (such as the default FreeBSD linker) concatenate
     // .MIPS.abiflags instead of merging. To allow for this case (or potential
@@ -175,8 +176,10 @@ MipsAbiFlagsSection<ELFT> *MipsAbiFlagsSection<ELFT>::create() {
 // .MIPS.options section.
 template <class ELFT>
 MipsOptionsSection<ELFT>::MipsOptionsSection(Elf_Mips_RegInfo Reginfo)
-    : SyntheticSection<ELFT>(SHF_ALLOC, SHT_MIPS_OPTIONS, 8, ".MIPS.options"),
-      Reginfo(Reginfo) {}
+    : SyntheticSection(SHF_ALLOC, SHT_MIPS_OPTIONS, 8, ".MIPS.options"),
+      Reginfo(Reginfo) {
+  this->Entsize = sizeof(Elf_Mips_Options) + sizeof(Elf_Mips_RegInfo);
+}
 
 template <class ELFT> void MipsOptionsSection<ELFT>::writeTo(uint8_t *Buf) {
   auto *Options = reinterpret_cast<Elf_Mips_Options *>(Buf);
@@ -184,7 +187,7 @@ template <class ELFT> void MipsOptionsSection<ELFT>::writeTo(uint8_t *Buf) {
   Options->size = getSize();
 
   if (!Config->Relocatable)
-    Reginfo.ri_gp_value = In<ELFT>::MipsGot->getGp();
+    Reginfo.ri_gp_value = InX::MipsGot->getGp();
   memcpy(Buf + sizeof(Elf_Mips_Options), &Reginfo, sizeof(Reginfo));
 }
 
@@ -197,13 +200,13 @@ MipsOptionsSection<ELFT> *MipsOptionsSection<ELFT>::create() {
   Elf_Mips_RegInfo Reginfo = {};
   bool Create = false;
 
-  for (InputSectionBase<ELFT> *Sec : Symtab<ELFT>::X->Sections) {
-    if (!Sec->Live || Sec->Type != SHT_MIPS_OPTIONS)
+  for (InputSectionBase *Sec : InputSections) {
+    if (Sec->Type != SHT_MIPS_OPTIONS)
       continue;
     Sec->Live = false;
     Create = true;
 
-    std::string Filename = toString(Sec->getFile());
+    std::string Filename = toString(Sec->getFile<ELFT>());
     ArrayRef<uint8_t> D = Sec->Data;
 
     while (!D.empty()) {
@@ -217,7 +220,7 @@ MipsOptionsSection<ELFT> *MipsOptionsSection<ELFT>::create() {
         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()->MipsGp0 = Opt->getRegInfo().ri_gp_value;
+        Sec->getFile<ELFT>()->MipsGp0 = Opt->getRegInfo().ri_gp_value;
         break;
       }
 
@@ -235,12 +238,14 @@ MipsOptionsSection<ELFT> *MipsOptionsSection<ELFT>::create() {
 // MIPS .reginfo section.
 template <class ELFT>
 MipsReginfoSection<ELFT>::MipsReginfoSection(Elf_Mips_RegInfo Reginfo)
-    : SyntheticSection<ELFT>(SHF_ALLOC, SHT_MIPS_REGINFO, 4, ".reginfo"),
-      Reginfo(Reginfo) {}
+    : SyntheticSection(SHF_ALLOC, SHT_MIPS_REGINFO, 4, ".reginfo"),
+      Reginfo(Reginfo) {
+  this->Entsize = sizeof(Elf_Mips_RegInfo);
+}
 
 template <class ELFT> void MipsReginfoSection<ELFT>::writeTo(uint8_t *Buf) {
   if (!Config->Relocatable)
-    Reginfo.ri_gp_value = In<ELFT>::MipsGot->getGp();
+    Reginfo.ri_gp_value = InX::MipsGot->getGp();
   memcpy(Buf, &Reginfo, sizeof(Reginfo));
 }
 
@@ -253,22 +258,24 @@ MipsReginfoSection<ELFT> *MipsReginfoSection<ELFT>::create() {
   Elf_Mips_RegInfo Reginfo = {};
   bool Create = false;
 
-  for (InputSectionBase<ELFT> *Sec : Symtab<ELFT>::X->Sections) {
-    if (!Sec->Live || Sec->Type != SHT_MIPS_REGINFO)
+  for (InputSectionBase *Sec : InputSections) {
+    if (Sec->Type != SHT_MIPS_REGINFO)
       continue;
     Sec->Live = false;
     Create = true;
 
     if (Sec->Data.size() != sizeof(Elf_Mips_RegInfo)) {
-      error(toString(Sec->getFile()) + ": invalid size of .reginfo section");
+      error(toString(Sec->getFile<ELFT>()) +
+            ": 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->getFile()) + ": unsupported non-zero ri_gp_value");
+      error(toString(Sec->getFile<ELFT>()) +
+            ": unsupported non-zero ri_gp_value");
 
     Reginfo.ri_gprmask |= R->ri_gprmask;
-    Sec->getFile()->MipsGp0 = R->ri_gp_value;
+    Sec->getFile<ELFT>()->MipsGp0 = R->ri_gp_value;
   };
 
   if (Create)
@@ -276,15 +283,24 @@ MipsReginfoSection<ELFT> *MipsReginfoSection<ELFT>::create() {
   return nullptr;
 }
 
-template <class ELFT> InputSection<ELFT> *elf::createInterpSection() {
-  auto *Ret = make<InputSection<ELFT>>(SHF_ALLOC, SHT_PROGBITS, 1,
-                                       ArrayRef<uint8_t>(), ".interp");
-  Ret->Live = true;
-
+InputSection *elf::createInterpSection() {
   // StringSaver guarantees that the returned string ends with '\0'.
   StringRef S = Saver.save(Config->DynamicLinker);
-  Ret->Data = {(const uint8_t *)S.data(), S.size() + 1};
-  return Ret;
+  ArrayRef<uint8_t> Contents = {(const uint8_t *)S.data(), S.size() + 1};
+
+  auto *Sec =
+      make<InputSection>(SHF_ALLOC, SHT_PROGBITS, 1, Contents, ".interp");
+  Sec->Live = true;
+  return Sec;
+}
+
+SymbolBody *elf::addSyntheticLocal(StringRef Name, uint8_t Type, uint64_t Value,
+                                   uint64_t Size, InputSectionBase *Section) {
+  auto *S = make<DefinedRegular>(Name, /*IsLocal*/ true, STV_DEFAULT, Type,
+                                 Value, Size, Section, nullptr);
+  if (InX::SymTab)
+    InX::SymTab->addSymbol(S);
+  return S;
 }
 
 static size_t getHashSize() {
@@ -303,16 +319,15 @@ static size_t getHashSize() {
   }
 }
 
-template <class ELFT>
-BuildIdSection<ELFT>::BuildIdSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC, SHT_NOTE, 1, ".note.gnu.build-id"),
+BuildIdSection::BuildIdSection()
+    : SyntheticSection(SHF_ALLOC, SHT_NOTE, 1, ".note.gnu.build-id"),
       HashSize(getHashSize()) {}
 
-template <class ELFT> void BuildIdSection<ELFT>::writeTo(uint8_t *Buf) {
-  const endianness E = ELFT::TargetEndianness;
-  write32<E>(Buf, 4);                   // Name size
-  write32<E>(Buf + 4, HashSize);        // Content size
-  write32<E>(Buf + 8, NT_GNU_BUILD_ID); // Type
+void BuildIdSection::writeTo(uint8_t *Buf) {
+  endianness E = Config->Endianness;
+  write32(Buf, 4, E);                   // Name size
+  write32(Buf + 4, HashSize, E);        // Content size
+  write32(Buf + 8, NT_GNU_BUILD_ID, E); // Type
   memcpy(Buf + 12, "GNU", 4);           // Name string
   HashBuf = Buf + 16;
 }
@@ -334,23 +349,33 @@ static std::vector<ArrayRef<uint8_t>> split(ArrayRef<uint8_t> Arr,
 // In order to utilize multiple cores, we first split data into 1MB
 // chunks, compute a hash for each chunk, and then compute a hash value
 // of the hash values.
-template <class ELFT>
-void BuildIdSection<ELFT>::computeHash(
+void BuildIdSection::computeHash(
     llvm::ArrayRef<uint8_t> Data,
     std::function<void(uint8_t *Dest, ArrayRef<uint8_t> Arr)> HashFn) {
   std::vector<ArrayRef<uint8_t>> Chunks = split(Data, 1024 * 1024);
   std::vector<uint8_t> Hashes(Chunks.size() * HashSize);
 
   // Compute hash values.
-  forLoop(0, Chunks.size(),
-          [&](size_t I) { HashFn(Hashes.data() + I * HashSize, Chunks[I]); });
+  parallelForEachN(0, Chunks.size(), [&](size_t I) {
+    HashFn(Hashes.data() + I * HashSize, Chunks[I]);
+  });
 
   // Write to the final output buffer.
   HashFn(HashBuf, Hashes);
 }
 
-template <class ELFT>
-void BuildIdSection<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
+BssSection::BssSection(StringRef Name)
+    : SyntheticSection(SHF_ALLOC | SHF_WRITE, SHT_NOBITS, 0, Name) {}
+
+size_t BssSection::reserveSpace(uint64_t Size, uint32_t Alignment) {
+  if (OutputSection *Sec = getParent())
+    Sec->updateAlignment(Alignment);
+  this->Size = alignTo(this->Size, Alignment) + Size;
+  this->Alignment = std::max(this->Alignment, Alignment);
+  return this->Size - Size;
+}
+
+void BuildIdSection::writeBuildId(ArrayRef<uint8_t> Buf) {
   switch (Config->BuildId) {
   case BuildIdKind::Fast:
     computeHash(Buf, [](uint8_t *Dest, ArrayRef<uint8_t> Arr) {
@@ -380,16 +405,229 @@ void BuildIdSection<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) {
 }
 
 template <class ELFT>
-GotSection<ELFT>::GotSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
-                             Target->GotEntrySize, ".got") {}
+EhFrameSection<ELFT>::EhFrameSection()
+    : SyntheticSection(SHF_ALLOC, SHT_PROGBITS, 1, ".eh_frame") {}
+
+// Search for an existing CIE record or create a new one.
+// CIE records from input object files are uniquified by their contents
+// and where their relocations point to.
+template <class ELFT>
+template <class RelTy>
+CieRecord *EhFrameSection<ELFT>::addCie(EhSectionPiece &Piece,
+                                        ArrayRef<RelTy> Rels) {
+  auto *Sec = cast<EhInputSection>(Piece.ID);
+  const endianness E = ELFT::TargetEndianness;
+  if (read32<E>(Piece.data().data() + 4) != 0)
+    fatal(toString(Sec) + ": CIE expected at beginning of .eh_frame");
+
+  SymbolBody *Personality = nullptr;
+  unsigned FirstRelI = Piece.FirstRelocation;
+  if (FirstRelI != (unsigned)-1)
+    Personality =
+        &Sec->template getFile<ELFT>()->getRelocTargetSym(Rels[FirstRelI]);
+
+  // Search for an existing CIE by CIE contents/relocation target pair.
+  CieRecord *Cie = &CieMap[{Piece.data(), Personality}];
+
+  // If not found, create a new one.
+  if (Cie->Piece == nullptr) {
+    Cie->Piece = &Piece;
+    Cies.push_back(Cie);
+  }
+  return Cie;
+}
+
+// There is one FDE per function. Returns true if a given FDE
+// points to a live function.
+template <class ELFT>
+template <class RelTy>
+bool EhFrameSection<ELFT>::isFdeLive(EhSectionPiece &Piece,
+                                     ArrayRef<RelTy> Rels) {
+  auto *Sec = cast<EhInputSection>(Piece.ID);
+  unsigned FirstRelI = Piece.FirstRelocation;
+  if (FirstRelI == (unsigned)-1)
+    return false;
+  const RelTy &Rel = Rels[FirstRelI];
+  SymbolBody &B = Sec->template getFile<ELFT>()->getRelocTargetSym(Rel);
+  auto *D = dyn_cast<DefinedRegular>(&B);
+  if (!D || !D->Section)
+    return false;
+  auto *Target =
+      cast<InputSectionBase>(cast<InputSectionBase>(D->Section)->Repl);
+  return Target && Target->Live;
+}
 
-template <class ELFT> void GotSection<ELFT>::addEntry(SymbolBody &Sym) {
+// .eh_frame is a sequence of CIE or FDE records. In general, there
+// is one CIE record per input object file which is followed by
+// a list of FDEs. This function searches an existing CIE or create a new
+// one and associates FDEs to the CIE.
+template <class ELFT>
+template <class RelTy>
+void EhFrameSection<ELFT>::addSectionAux(EhInputSection *Sec,
+                                         ArrayRef<RelTy> Rels) {
+  const endianness E = ELFT::TargetEndianness;
+
+  DenseMap<size_t, CieRecord *> OffsetToCie;
+  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<E>(Piece.data().data() + 4);
+    if (ID == 0) {
+      OffsetToCie[Offset] = addCie(Piece, Rels);
+      continue;
+    }
+
+    uint32_t CieOffset = Offset + 4 - ID;
+    CieRecord *Cie = OffsetToCie[CieOffset];
+    if (!Cie)
+      fatal(toString(Sec) + ": invalid CIE reference");
+
+    if (!isFdeLive(Piece, Rels))
+      continue;
+    Cie->FdePieces.push_back(&Piece);
+    NumFdes++;
+  }
+}
+
+template <class ELFT>
+void EhFrameSection<ELFT>::addSection(InputSectionBase *C) {
+  auto *Sec = cast<EhInputSection>(C);
+  Sec->Parent = this;
+  updateAlignment(Sec->Alignment);
+  Sections.push_back(Sec);
+  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;
+
+  if (Sec->NumRelocations) {
+    if (Sec->AreRelocsRela)
+      addSectionAux(Sec, Sec->template relas<ELFT>());
+    else
+      addSectionAux(Sec, Sec->template rels<ELFT>());
+    return;
+  }
+  addSectionAux(Sec, makeArrayRef<Elf_Rela>(nullptr, nullptr));
+}
+
+template <class ELFT>
+static void writeCieFde(uint8_t *Buf, ArrayRef<uint8_t> D) {
+  memcpy(Buf, D.data(), D.size());
+
+  // Fix the size field. -4 since size does not include the size field itself.
+  const endianness E = ELFT::TargetEndianness;
+  write32<E>(Buf, alignTo(D.size(), sizeof(typename ELFT::uint)) - 4);
+}
+
+template <class ELFT> void EhFrameSection<ELFT>::finalizeContents() {
+  if (this->Size)
+    return; // Already finalized.
+
+  size_t Off = 0;
+  for (CieRecord *Cie : Cies) {
+    Cie->Piece->OutputOff = Off;
+    Off += alignTo(Cie->Piece->size(), Config->Wordsize);
+
+    for (EhSectionPiece *Fde : Cie->FdePieces) {
+      Fde->OutputOff = Off;
+      Off += alignTo(Fde->size(), Config->Wordsize);
+    }
+  }
+
+  // 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;
+
+  this->Size = Off;
+}
+
+template <class ELFT> static uint64_t readFdeAddr(uint8_t *Buf, int Size) {
+  const endianness E = ELFT::TargetEndianness;
+  switch (Size) {
+  case DW_EH_PE_udata2:
+    return read16<E>(Buf);
+  case DW_EH_PE_udata4:
+    return read32<E>(Buf);
+  case DW_EH_PE_udata8:
+    return read64<E>(Buf);
+  case DW_EH_PE_absptr:
+    if (ELFT::Is64Bits)
+      return read64<E>(Buf);
+    return read32<E>(Buf);
+  }
+  fatal("unknown FDE size encoding");
+}
+
+// Returns the VA to which a given FDE (on a mmap'ed buffer) is applied to.
+// We need it to create .eh_frame_hdr section.
+template <class ELFT>
+uint64_t EhFrameSection<ELFT>::getFdePc(uint8_t *Buf, size_t FdeOff,
+                                        uint8_t Enc) {
+  // The starting address to which this FDE applies is
+  // stored at FDE + 8 byte.
+  size_t Off = FdeOff + 8;
+  uint64_t Addr = readFdeAddr<ELFT>(Buf + Off, Enc & 0x7);
+  if ((Enc & 0x70) == DW_EH_PE_absptr)
+    return Addr;
+  if ((Enc & 0x70) == DW_EH_PE_pcrel)
+    return Addr + getParent()->Addr + Off;
+  fatal("unknown FDE size relative encoding");
+}
+
+template <class ELFT> void EhFrameSection<ELFT>::writeTo(uint8_t *Buf) {
+  const endianness E = ELFT::TargetEndianness;
+  for (CieRecord *Cie : Cies) {
+    size_t CieOffset = Cie->Piece->OutputOff;
+    writeCieFde<ELFT>(Buf + CieOffset, Cie->Piece->data());
+
+    for (EhSectionPiece *Fde : Cie->FdePieces) {
+      size_t Off = Fde->OutputOff;
+      writeCieFde<ELFT>(Buf + Off, Fde->data());
+
+      // FDE's second word should have the offset to an associated CIE.
+      // Write it.
+      write32<E>(Buf + Off + 4, Off + 4 - CieOffset);
+    }
+  }
+
+  for (EhInputSection *S : Sections)
+    S->relocateAlloc(Buf, nullptr);
+
+  // Construct .eh_frame_hdr. .eh_frame_hdr is a binary search table
+  // to get a FDE from an address to which FDE is applied. So here
+  // we obtain two addresses and pass them to EhFrameHdr object.
+  if (In<ELFT>::EhFrameHdr) {
+    for (CieRecord *Cie : Cies) {
+      uint8_t Enc = getFdeEncoding<ELFT>(Cie->Piece);
+      for (SectionPiece *Fde : Cie->FdePieces) {
+        uint64_t Pc = getFdePc(Buf, Fde->OutputOff, Enc);
+        uint64_t FdeVA = getParent()->Addr + Fde->OutputOff;
+        In<ELFT>::EhFrameHdr->addFde(Pc, FdeVA);
+      }
+    }
+  }
+}
+
+GotSection::GotSection()
+    : SyntheticSection(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
+                       Target->GotEntrySize, ".got") {}
+
+void GotSection::addEntry(SymbolBody &Sym) {
   Sym.GotIndex = NumEntries;
   ++NumEntries;
 }
 
-template <class ELFT> bool GotSection<ELFT>::addDynTlsEntry(SymbolBody &Sym) {
+bool GotSection::addDynTlsEntry(SymbolBody &Sym) {
   if (Sym.GlobalDynIndex != -1U)
     return false;
   Sym.GlobalDynIndex = NumEntries;
@@ -400,48 +638,42 @@ template <class ELFT> bool GotSection<ELFT>::addDynTlsEntry(SymbolBody &Sym) {
 
 // Reserves TLS entries for a TLS module ID and a TLS block offset.
 // In total it takes two GOT slots.
-template <class ELFT> bool GotSection<ELFT>::addTlsIndex() {
+bool GotSection::addTlsIndex() {
   if (TlsIndexOff != uint32_t(-1))
     return false;
-  TlsIndexOff = NumEntries * sizeof(uintX_t);
+  TlsIndexOff = NumEntries * Config->Wordsize;
   NumEntries += 2;
   return true;
 }
 
-template <class ELFT>
-typename GotSection<ELFT>::uintX_t
-GotSection<ELFT>::getGlobalDynAddr(const SymbolBody &B) const {
-  return this->getVA() + B.GlobalDynIndex * sizeof(uintX_t);
+uint64_t GotSection::getGlobalDynAddr(const SymbolBody &B) const {
+  return this->getVA() + B.GlobalDynIndex * Config->Wordsize;
 }
 
-template <class ELFT>
-typename GotSection<ELFT>::uintX_t
-GotSection<ELFT>::getGlobalDynOffset(const SymbolBody &B) const {
-  return B.GlobalDynIndex * sizeof(uintX_t);
+uint64_t GotSection::getGlobalDynOffset(const SymbolBody &B) const {
+  return B.GlobalDynIndex * Config->Wordsize;
 }
 
-template <class ELFT> void GotSection<ELFT>::finalize() {
-  Size = NumEntries * sizeof(uintX_t);
-}
+void GotSection::finalizeContents() { Size = NumEntries * Config->Wordsize; }
 
-template <class ELFT> bool GotSection<ELFT>::empty() const {
+bool GotSection::empty() const {
   // If we have a relocation that is relative to GOT (such as GOTOFFREL),
   // we need to emit a GOT even if it's empty.
   return NumEntries == 0 && !HasGotOffRel;
 }
 
-template <class ELFT> void GotSection<ELFT>::writeTo(uint8_t *Buf) {
-  this->relocate(Buf, Buf + Size);
+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.
+  relocateAlloc(Buf - OutSecOff, Buf - OutSecOff + Size);
 }
 
-template <class ELFT>
-MipsGotSection<ELFT>::MipsGotSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE | SHF_MIPS_GPREL,
-                             SHT_PROGBITS, 16, ".got") {}
+MipsGotSection::MipsGotSection()
+    : SyntheticSection(SHF_ALLOC | SHF_WRITE | SHF_MIPS_GPREL, SHT_PROGBITS, 16,
+                       ".got") {}
 
-template <class ELFT>
-void MipsGotSection<ELFT>::addEntry(SymbolBody &Sym, uintX_t Addend,
-                                    RelExpr Expr) {
+void MipsGotSection::addEntry(SymbolBody &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:
   //
@@ -472,7 +704,7 @@ void MipsGotSection<ELFT>::addEntry(SymbolBody &Sym, uintX_t Addend,
     // 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({cast<DefinedRegular<ELFT>>(&Sym)->Section->OutSec, 0});
+    PageIndexMap.insert({Sym.getOutputSection(), 0});
     return;
   }
   if (Sym.isTls()) {
@@ -483,7 +715,7 @@ void MipsGotSection<ELFT>::addEntry(SymbolBody &Sym, uintX_t Addend,
     TlsEntries.push_back(&Sym);
     return;
   }
-  auto AddEntry = [&](SymbolBody &S, uintX_t A, GotEntries &Items) {
+  auto AddEntry = [&](SymbolBody &S, uint64_t A, GotEntries &Items) {
     if (S.isInGot() && !A)
       return;
     size_t NewIndex = Items.size();
@@ -508,8 +740,7 @@ void MipsGotSection<ELFT>::addEntry(SymbolBody &Sym, uintX_t Addend,
   }
 }
 
-template <class ELFT>
-bool MipsGotSection<ELFT>::addDynTlsEntry(SymbolBody &Sym) {
+bool MipsGotSection::addDynTlsEntry(SymbolBody &Sym) {
   if (Sym.GlobalDynIndex != -1U)
     return false;
   Sym.GlobalDynIndex = TlsEntries.size();
@@ -521,10 +752,10 @@ bool MipsGotSection<ELFT>::addDynTlsEntry(SymbolBody &Sym) {
 
 // Reserves TLS entries for a TLS module ID and a TLS block offset.
 // In total it takes two GOT slots.
-template <class ELFT> bool MipsGotSection<ELFT>::addTlsIndex() {
+bool MipsGotSection::addTlsIndex() {
   if (TlsIndexOff != uint32_t(-1))
     return false;
-  TlsIndexOff = TlsEntries.size() * sizeof(uintX_t);
+  TlsIndexOff = TlsEntries.size() * Config->Wordsize;
   TlsEntries.push_back(nullptr);
   TlsEntries.push_back(nullptr);
   return true;
@@ -538,25 +769,20 @@ static uint64_t getMipsPageCount(uint64_t Size) {
   return (Size + 0xfffe) / 0xffff + 1;
 }
 
-template <class ELFT>
-typename MipsGotSection<ELFT>::uintX_t
-MipsGotSection<ELFT>::getPageEntryOffset(const SymbolBody &B,
-                                         uintX_t Addend) const {
-  const OutputSectionBase *OutSec =
-      cast<DefinedRegular<ELFT>>(&B)->Section->OutSec;
-  uintX_t SecAddr = getMipsPageAddr(OutSec->Addr);
-  uintX_t SymAddr = getMipsPageAddr(B.getVA<ELFT>(Addend));
-  uintX_t Index = PageIndexMap.lookup(OutSec) + (SymAddr - SecAddr) / 0xffff;
+uint64_t MipsGotSection::getPageEntryOffset(const SymbolBody &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) * sizeof(uintX_t);
+  return (HeaderEntriesNum + Index) * Config->Wordsize;
 }
 
-template <class ELFT>
-typename MipsGotSection<ELFT>::uintX_t
-MipsGotSection<ELFT>::getBodyEntryOffset(const SymbolBody &B,
-                                         uintX_t Addend) const {
+uint64_t MipsGotSection::getBodyEntryOffset(const SymbolBody &B,
+                                            int64_t Addend) const {
   // Calculate offset of the GOT entries block: TLS, global, local.
-  uintX_t Index = HeaderEntriesNum + PageEntriesNum;
+  uint64_t Index = HeaderEntriesNum + PageEntriesNum;
   if (B.isTls())
     Index += LocalEntries.size() + LocalEntries32.size() + GlobalEntries.size();
   else if (B.IsInGlobalMipsGot)
@@ -571,35 +797,31 @@ MipsGotSection<ELFT>::getBodyEntryOffset(const SymbolBody &B,
     assert(It != EntryIndexMap.end());
     Index += It->second;
   }
-  return Index * sizeof(uintX_t);
+  return Index * Config->Wordsize;
 }
 
-template <class ELFT>
-typename MipsGotSection<ELFT>::uintX_t
-MipsGotSection<ELFT>::getTlsOffset() const {
-  return (getLocalEntriesNum() + GlobalEntries.size()) * sizeof(uintX_t);
+uint64_t MipsGotSection::getTlsOffset() const {
+  return (getLocalEntriesNum() + GlobalEntries.size()) * Config->Wordsize;
 }
 
-template <class ELFT>
-typename MipsGotSection<ELFT>::uintX_t
-MipsGotSection<ELFT>::getGlobalDynOffset(const SymbolBody &B) const {
-  return B.GlobalDynIndex * sizeof(uintX_t);
+uint64_t MipsGotSection::getGlobalDynOffset(const SymbolBody &B) const {
+  return B.GlobalDynIndex * Config->Wordsize;
 }
 
-template <class ELFT>
-const SymbolBody *MipsGotSection<ELFT>::getFirstGlobalEntry() const {
+const SymbolBody *MipsGotSection::getFirstGlobalEntry() const {
   return GlobalEntries.empty() ? nullptr : GlobalEntries.front().first;
 }
 
-template <class ELFT>
-unsigned MipsGotSection<ELFT>::getLocalEntriesNum() const {
+unsigned MipsGotSection::getLocalEntriesNum() const {
   return HeaderEntriesNum + PageEntriesNum + LocalEntries.size() +
          LocalEntries32.size();
 }
 
-template <class ELFT> void MipsGotSection<ELFT>::finalize() {
+void MipsGotSection::finalizeContents() { updateAllocSize(); }
+
+void MipsGotSection::updateAllocSize() {
   PageEntriesNum = 0;
-  for (std::pair<const OutputSectionBase *, size_t> &P : PageIndexMap) {
+  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 -
@@ -610,27 +832,31 @@ template <class ELFT> void MipsGotSection<ELFT>::finalize() {
     PageEntriesNum += getMipsPageCount(P.first->Size);
   }
   Size = (getLocalEntriesNum() + GlobalEntries.size() + TlsEntries.size()) *
-         sizeof(uintX_t);
+         Config->Wordsize;
 }
 
-template <class ELFT> bool MipsGotSection<ELFT>::empty() const {
+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;
 }
 
-template <class ELFT>
-typename MipsGotSection<ELFT>::uintX_t MipsGotSection<ELFT>::getGp() const {
-  return ElfSym<ELFT>::MipsGp->template getVA<ELFT>(0);
+uint64_t MipsGotSection::getGp() const { return ElfSym::MipsGp->getVA(0); }
+
+static uint64_t readUint(uint8_t *Buf) {
+  if (Config->Is64)
+    return read64(Buf, Config->Endianness);
+  return read32(Buf, Config->Endianness);
 }
 
-template <class ELFT>
-static void writeUint(uint8_t *Buf, typename ELFT::uint Val) {
-  typedef typename ELFT::uint uintX_t;
-  write<uintX_t, ELFT::TargetEndianness, sizeof(uintX_t)>(Buf, Val);
+static void writeUint(uint8_t *Buf, uint64_t Val) {
+  if (Config->Is64)
+    write64(Buf, Val, Config->Endianness);
+  else
+    write32(Buf, Val, Config->Endianness);
 }
 
-template <class ELFT> void MipsGotSection<ELFT>::writeTo(uint8_t *Buf) {
+void MipsGotSection::writeTo(uint8_t *Buf) {
   // Set the MSB of the second GOT slot. This is not required by any
   // MIPS ABI documentation, though.
   //
@@ -645,25 +871,24 @@ template <class ELFT> void MipsGotSection<ELFT>::writeTo(uint8_t *Buf) {
   // we've been doing this for years, it is probably a safe bet to
   // keep doing this for now. We really need to revisit this to see
   // if we had to do this.
-  auto *P = reinterpret_cast<typename ELFT::Off *>(Buf);
-  P[1] = uintX_t(1) << (ELFT::Is64Bits ? 63 : 31);
-  Buf += HeaderEntriesNum * sizeof(uintX_t);
+  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 OutputSectionBase *, size_t> &L : PageIndexMap) {
+  for (std::pair<const OutputSection *, size_t> &L : PageIndexMap) {
     size_t PageCount = getMipsPageCount(L.first->Size);
-    uintX_t FirstPageAddr = getMipsPageAddr(L.first->Addr);
+    uint64_t FirstPageAddr = getMipsPageAddr(L.first->Addr);
     for (size_t PI = 0; PI < PageCount; ++PI) {
-      uint8_t *Entry = Buf + (L.second + PI) * sizeof(uintX_t);
-      writeUint<ELFT>(Entry, FirstPageAddr + PI * 0x10000);
+      uint8_t *Entry = Buf + (L.second + PI) * Config->Wordsize;
+      writeUint(Entry, FirstPageAddr + PI * 0x10000);
     }
   }
-  Buf += PageEntriesNum * sizeof(uintX_t);
+  Buf += PageEntriesNum * Config->Wordsize;
   auto AddEntry = [&](const GotEntry &SA) {
     uint8_t *Entry = Buf;
-    Buf += sizeof(uintX_t);
+    Buf += Config->Wordsize;
     const SymbolBody *Body = SA.first;
-    uintX_t VA = Body->template getVA<ELFT>(SA.second);
-    writeUint<ELFT>(Entry, VA);
+    uint64_t VA = Body->getVA(SA.second);
+    writeUint(Entry, VA);
   };
   std::for_each(std::begin(LocalEntries), std::end(LocalEntries), AddEntry);
   std::for_each(std::begin(LocalEntries32), std::end(LocalEntries32), AddEntry);
@@ -674,86 +899,83 @@ template <class ELFT> void MipsGotSection<ELFT>::writeTo(uint8_t *Buf) {
   // for thread-local storage.
   // https://www.linux-mips.org/wiki/NPTL
   if (TlsIndexOff != -1U && !Config->Pic)
-    writeUint<ELFT>(Buf + TlsIndexOff, 1);
+    writeUint(Buf + TlsIndexOff, 1);
   for (const SymbolBody *B : TlsEntries) {
     if (!B || B->isPreemptible())
       continue;
-    uintX_t VA = B->getVA<ELFT>();
+    uint64_t VA = B->getVA();
     if (B->GotIndex != -1U) {
-      uint8_t *Entry = Buf + B->GotIndex * sizeof(uintX_t);
-      writeUint<ELFT>(Entry, VA - 0x7000);
+      uint8_t *Entry = Buf + B->GotIndex * Config->Wordsize;
+      writeUint(Entry, VA - 0x7000);
     }
     if (B->GlobalDynIndex != -1U) {
-      uint8_t *Entry = Buf + B->GlobalDynIndex * sizeof(uintX_t);
-      writeUint<ELFT>(Entry, 1);
-      Entry += sizeof(uintX_t);
-      writeUint<ELFT>(Entry, VA - 0x8000);
+      uint8_t *Entry = Buf + B->GlobalDynIndex * Config->Wordsize;
+      writeUint(Entry, 1);
+      Entry += Config->Wordsize;
+      writeUint(Entry, VA - 0x8000);
     }
   }
 }
 
-template <class ELFT>
-GotPltSection<ELFT>::GotPltSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
-                             Target->GotPltEntrySize, ".got.plt") {}
+GotPltSection::GotPltSection()
+    : SyntheticSection(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
+                       Target->GotPltEntrySize, ".got.plt") {}
 
-template <class ELFT> void GotPltSection<ELFT>::addEntry(SymbolBody &Sym) {
+void GotPltSection::addEntry(SymbolBody &Sym) {
   Sym.GotPltIndex = Target->GotPltHeaderEntriesNum + Entries.size();
   Entries.push_back(&Sym);
 }
 
-template <class ELFT> size_t GotPltSection<ELFT>::getSize() const {
+size_t GotPltSection::getSize() const {
   return (Target->GotPltHeaderEntriesNum + Entries.size()) *
          Target->GotPltEntrySize;
 }
 
-template <class ELFT> void GotPltSection<ELFT>::writeTo(uint8_t *Buf) {
+void GotPltSection::writeTo(uint8_t *Buf) {
   Target->writeGotPltHeader(Buf);
   Buf += Target->GotPltHeaderEntriesNum * Target->GotPltEntrySize;
   for (const SymbolBody *B : Entries) {
     Target->writeGotPlt(Buf, *B);
-    Buf += sizeof(uintX_t);
+    Buf += Config->Wordsize;
   }
 }
 
 // On ARM the IgotPltSection is part of the GotSection, on other Targets it is
 // part of the .got.plt
-template <class ELFT>
-IgotPltSection<ELFT>::IgotPltSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
-                             Target->GotPltEntrySize,
-                             Config->EMachine == EM_ARM ? ".got" : ".got.plt") {
-}
+IgotPltSection::IgotPltSection()
+    : SyntheticSection(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
+                       Target->GotPltEntrySize,
+                       Config->EMachine == EM_ARM ? ".got" : ".got.plt") {}
 
-template <class ELFT> void IgotPltSection<ELFT>::addEntry(SymbolBody &Sym) {
+void IgotPltSection::addEntry(SymbolBody &Sym) {
   Sym.IsInIgot = true;
   Sym.GotPltIndex = Entries.size();
   Entries.push_back(&Sym);
 }
 
-template <class ELFT> size_t IgotPltSection<ELFT>::getSize() const {
+size_t IgotPltSection::getSize() const {
   return Entries.size() * Target->GotPltEntrySize;
 }
 
-template <class ELFT> void IgotPltSection<ELFT>::writeTo(uint8_t *Buf) {
+void IgotPltSection::writeTo(uint8_t *Buf) {
   for (const SymbolBody *B : Entries) {
     Target->writeIgotPlt(Buf, *B);
-    Buf += sizeof(uintX_t);
+    Buf += Config->Wordsize;
   }
 }
 
-template <class ELFT>
-StringTableSection<ELFT>::StringTableSection(StringRef Name, bool Dynamic)
-    : SyntheticSection<ELFT>(Dynamic ? (uintX_t)SHF_ALLOC : 0, SHT_STRTAB, 1,
-                             Name),
-      Dynamic(Dynamic) {}
+StringTableSection::StringTableSection(StringRef Name, bool Dynamic)
+    : SyntheticSection(Dynamic ? (uint64_t)SHF_ALLOC : 0, SHT_STRTAB, 1, Name),
+      Dynamic(Dynamic) {
+  // ELF string tables start with a NUL byte.
+  addString("");
+}
 
 // Adds a string to the string table. If HashIt is true we hash and check for
 // duplicates. It is optional because the name of global symbols are already
 // uniqued and hashing them again has a big cost for a small value: uniquing
 // them with some other string that happens to be the same.
-template <class ELFT>
-unsigned StringTableSection<ELFT>::addString(StringRef S, bool HashIt) {
+unsigned StringTableSection::addString(StringRef S, bool HashIt) {
   if (HashIt) {
     auto R = StringMap.insert(std::make_pair(S, this->Size));
     if (!R.second)
@@ -765,9 +987,7 @@ unsigned StringTableSection<ELFT>::addString(StringRef S, bool HashIt) {
   return Ret;
 }
 
-template <class ELFT> void StringTableSection<ELFT>::writeTo(uint8_t *Buf) {
-  // ELF string tables start with NUL byte, so advance the pointer by one.
-  ++Buf;
+void StringTableSection::writeTo(uint8_t *Buf) {
   for (StringRef S : Strings) {
     memcpy(Buf, S.data(), S.size());
     Buf += S.size() + 1;
@@ -781,13 +1001,15 @@ static unsigned getVerDefNum() { return Config->VersionDefinitions.size() + 1; }
 
 template <class ELFT>
 DynamicSection<ELFT>::DynamicSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_DYNAMIC,
-                             sizeof(uintX_t), ".dynamic") {
+    : SyntheticSection(SHF_ALLOC | SHF_WRITE, SHT_DYNAMIC, Config->Wordsize,
+                       ".dynamic") {
   this->Entsize = ELFT::Is64Bits ? 16 : 8;
-  // .dynamic section is not writable on MIPS.
+
+  // .dynamic section is not writable on MIPS and on Fuchsia OS
+  // which passes -z rodynamic.
   // See "Special Section" in Chapter 4 in the following document:
   // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
-  if (Config->EMachine == EM_MIPS)
+  if (Config->EMachine == EM_MIPS || Config->ZRodynamic)
     this->Flags = SHF_ALLOC;
 
   addEntries();
@@ -798,16 +1020,18 @@ DynamicSection<ELFT>::DynamicSection()
 template <class ELFT> void DynamicSection<ELFT>::addEntries() {
   // Add strings to .dynstr early so that .dynstr's size will be
   // fixed early.
+  for (StringRef S : Config->FilterList)
+    add({DT_FILTER, InX::DynStrTab->addString(S)});
   for (StringRef S : Config->AuxiliaryList)
-    add({DT_AUXILIARY, In<ELFT>::DynStrTab->addString(S)});
-  if (!Config->RPath.empty())
+    add({DT_AUXILIARY, InX::DynStrTab->addString(S)});
+  if (!Config->Rpath.empty())
     add({Config->EnableNewDtags ? DT_RUNPATH : DT_RPATH,
-         In<ELFT>::DynStrTab->addString(Config->RPath)});
+         InX::DynStrTab->addString(Config->Rpath)});
   for (SharedFile<ELFT> *F : Symtab<ELFT>::X->getSharedFiles())
     if (F->isNeeded())
-      add({DT_NEEDED, In<ELFT>::DynStrTab->addString(F->getSoName())});
+      add({DT_NEEDED, InX::DynStrTab->addString(F->SoName)});
   if (!Config->SoName.empty())
-    add({DT_SONAME, In<ELFT>::DynStrTab->addString(Config->SoName)});
+    add({DT_SONAME, InX::DynStrTab->addString(Config->SoName)});
 
   // Set DT_FLAGS and DT_FLAGS_1.
   uint32_t DtFlags = 0;
@@ -832,22 +1056,31 @@ template <class ELFT> void DynamicSection<ELFT>::addEntries() {
   if (DtFlags1)
     add({DT_FLAGS_1, DtFlags1});
 
-  if (!Config->Shared && !Config->Relocatable)
+  // DT_DEBUG is a pointer to debug informaion used by debuggers at runtime. We
+  // need it for each process, so we don't write it for DSOs. The loader writes
+  // the pointer into this entry.
+  //
+  // DT_DEBUG is the only .dynamic entry that needs to be written to. Some
+  // systems (currently only Fuchsia OS) provide other means to give the
+  // debugger this information. Such systems may choose make .dynamic read-only.
+  // If the target is such a system (used -z rodynamic) don't write DT_DEBUG.
+  if (!Config->Shared && !Config->Relocatable && !Config->ZRodynamic)
     add({DT_DEBUG, (uint64_t)0});
 }
 
 // Add remaining entries to complete .dynamic contents.
-template <class ELFT> void DynamicSection<ELFT>::finalize() {
+template <class ELFT> void DynamicSection<ELFT>::finalizeContents() {
   if (this->Size)
     return; // Already finalized.
 
-  this->Link = In<ELFT>::DynStrTab->OutSec->SectionIndex;
-  if (In<ELFT>::RelaDyn->OutSec->Size > 0) {
-    bool IsRela = Config->Rela;
+  this->Link = InX::DynStrTab->getParent()->SectionIndex;
+  if (In<ELFT>::RelaDyn->getParent() && !In<ELFT>::RelaDyn->empty()) {
+    bool IsRela = Config->IsRela;
     add({IsRela ? DT_RELA : DT_REL, In<ELFT>::RelaDyn});
-    add({IsRela ? DT_RELASZ : DT_RELSZ, In<ELFT>::RelaDyn->OutSec->Size});
+    add({IsRela ? DT_RELASZ : DT_RELSZ, In<ELFT>::RelaDyn->getParent(),
+         Entry::SecSize});
     add({IsRela ? DT_RELAENT : DT_RELENT,
-         uintX_t(IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel))});
+         uint64_t(IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel))});
 
     // MIPS dynamic loader does not support RELCOUNT tag.
     // The problem is in the tight relation between dynamic
@@ -858,34 +1091,45 @@ template <class ELFT> void DynamicSection<ELFT>::finalize() {
         add({IsRela ? DT_RELACOUNT : DT_RELCOUNT, NumRelativeRels});
     }
   }
-  if (In<ELFT>::RelaPlt->OutSec->Size > 0) {
+  if (In<ELFT>::RelaPlt->getParent() && !In<ELFT>::RelaPlt->empty()) {
     add({DT_JMPREL, In<ELFT>::RelaPlt});
-    add({DT_PLTRELSZ, In<ELFT>::RelaPlt->OutSec->Size});
-    add({Config->EMachine == EM_MIPS ? DT_MIPS_PLTGOT : DT_PLTGOT,
-         In<ELFT>::GotPlt});
-    add({DT_PLTREL, uint64_t(Config->Rela ? DT_RELA : DT_REL)});
+    add({DT_PLTRELSZ, In<ELFT>::RelaPlt->getParent(), Entry::SecSize});
+    switch (Config->EMachine) {
+    case EM_MIPS:
+      add({DT_MIPS_PLTGOT, In<ELFT>::GotPlt});
+      break;
+    case EM_SPARCV9:
+      add({DT_PLTGOT, In<ELFT>::Plt});
+      break;
+    default:
+      add({DT_PLTGOT, In<ELFT>::GotPlt});
+      break;
+    }
+    add({DT_PLTREL, uint64_t(Config->IsRela ? DT_RELA : DT_REL)});
   }
 
-  add({DT_SYMTAB, In<ELFT>::DynSymTab});
+  add({DT_SYMTAB, InX::DynSymTab});
   add({DT_SYMENT, sizeof(Elf_Sym)});
-  add({DT_STRTAB, In<ELFT>::DynStrTab});
-  add({DT_STRSZ, In<ELFT>::DynStrTab->getSize()});
-  if (In<ELFT>::GnuHashTab)
-    add({DT_GNU_HASH, In<ELFT>::GnuHashTab});
+  add({DT_STRTAB, InX::DynStrTab});
+  add({DT_STRSZ, InX::DynStrTab->getSize()});
+  if (!Config->ZText)
+    add({DT_TEXTREL, (uint64_t)0});
+  if (InX::GnuHashTab)
+    add({DT_GNU_HASH, InX::GnuHashTab});
   if (In<ELFT>::HashTab)
     add({DT_HASH, In<ELFT>::HashTab});
 
-  if (Out<ELFT>::PreinitArray) {
-    add({DT_PREINIT_ARRAY, Out<ELFT>::PreinitArray});
-    add({DT_PREINIT_ARRAYSZ, Out<ELFT>::PreinitArray, Entry::SecSize});
+  if (Out::PreinitArray) {
+    add({DT_PREINIT_ARRAY, Out::PreinitArray});
+    add({DT_PREINIT_ARRAYSZ, Out::PreinitArray, Entry::SecSize});
   }
-  if (Out<ELFT>::InitArray) {
-    add({DT_INIT_ARRAY, Out<ELFT>::InitArray});
-    add({DT_INIT_ARRAYSZ, Out<ELFT>::InitArray, Entry::SecSize});
+  if (Out::InitArray) {
+    add({DT_INIT_ARRAY, Out::InitArray});
+    add({DT_INIT_ARRAYSZ, Out::InitArray, Entry::SecSize});
   }
-  if (Out<ELFT>::FiniArray) {
-    add({DT_FINI_ARRAY, Out<ELFT>::FiniArray});
-    add({DT_FINI_ARRAYSZ, Out<ELFT>::FiniArray, Entry::SecSize});
+  if (Out::FiniArray) {
+    add({DT_FINI_ARRAY, Out::FiniArray});
+    add({DT_FINI_ARRAYSZ, Out::FiniArray, Entry::SecSize});
   }
 
   if (SymbolBody *B = Symtab<ELFT>::X->findInCurrentDSO(Config->Init))
@@ -909,19 +1153,18 @@ template <class ELFT> void DynamicSection<ELFT>::finalize() {
     add({DT_MIPS_RLD_VERSION, 1});
     add({DT_MIPS_FLAGS, RHF_NOTPOT});
     add({DT_MIPS_BASE_ADDRESS, Config->ImageBase});
-    add({DT_MIPS_SYMTABNO, In<ELFT>::DynSymTab->getNumSymbols()});
-    add({DT_MIPS_LOCAL_GOTNO, In<ELFT>::MipsGot->getLocalEntriesNum()});
-    if (const SymbolBody *B = In<ELFT>::MipsGot->getFirstGlobalEntry())
+    add({DT_MIPS_SYMTABNO, InX::DynSymTab->getNumSymbols()});
+    add({DT_MIPS_LOCAL_GOTNO, InX::MipsGot->getLocalEntriesNum()});
+    if (const SymbolBody *B = InX::MipsGot->getFirstGlobalEntry())
       add({DT_MIPS_GOTSYM, B->DynsymIndex});
     else
-      add({DT_MIPS_GOTSYM, In<ELFT>::DynSymTab->getNumSymbols()});
-    add({DT_PLTGOT, In<ELFT>::MipsGot});
-    if (In<ELFT>::MipsRldMap)
-      add({DT_MIPS_RLD_MAP, In<ELFT>::MipsRldMap});
+      add({DT_MIPS_GOTSYM, InX::DynSymTab->getNumSymbols()});
+    add({DT_PLTGOT, InX::MipsGot});
+    if (InX::MipsRldMap)
+      add({DT_MIPS_RLD_MAP, InX::MipsRldMap});
   }
 
-  this->OutSec->Entsize = this->Entsize;
-  this->OutSec->Link = this->Link;
+  getParent()->Link = this->Link;
 
   // +1 for DT_NULL
   this->Size = (Entries.size() + 1) * this->Entsize;
@@ -937,13 +1180,13 @@ template <class ELFT> void DynamicSection<ELFT>::writeTo(uint8_t *Buf) {
       P->d_un.d_ptr = E.OutSec->Addr;
       break;
     case Entry::InSecAddr:
-      P->d_un.d_ptr = E.InSec->OutSec->Addr + E.InSec->OutSecOff;
+      P->d_un.d_ptr = E.InSec->getParent()->Addr + E.InSec->OutSecOff;
       break;
     case Entry::SecSize:
       P->d_un.d_val = E.OutSec->Size;
       break;
     case Entry::SymAddr:
-      P->d_un.d_ptr = E.Sym->template getVA<ELFT>();
+      P->d_un.d_ptr = E.Sym->getVA();
       break;
     case Entry::PlainInt:
       P->d_un.d_val = E.Val;
@@ -953,21 +1196,17 @@ template <class ELFT> void DynamicSection<ELFT>::writeTo(uint8_t *Buf) {
   }
 }
 
-template <class ELFT>
-typename ELFT::uint DynamicReloc<ELFT>::getOffset() const {
-  if (OutputSec)
-    return OutputSec->Addr + OffsetInSec;
-  return InputSec->OutSec->Addr + InputSec->getOffset(OffsetInSec);
+uint64_t DynamicReloc::getOffset() const {
+  return InputSec->getOutputSection()->Addr + InputSec->getOffset(OffsetInSec);
 }
 
-template <class ELFT>
-typename ELFT::uint DynamicReloc<ELFT>::getAddend() const {
+int64_t DynamicReloc::getAddend() const {
   if (UseSymVA)
-    return Sym->getVA<ELFT>(Addend);
+    return Sym->getVA(Addend);
   return Addend;
 }
 
-template <class ELFT> uint32_t DynamicReloc<ELFT>::getSymIndex() const {
+uint32_t DynamicReloc::getSymIndex() const {
   if (Sym && !UseSymVA)
     return Sym->DynsymIndex;
   return 0;
@@ -975,14 +1214,14 @@ template <class ELFT> uint32_t DynamicReloc<ELFT>::getSymIndex() const {
 
 template <class ELFT>
 RelocationSection<ELFT>::RelocationSection(StringRef Name, bool Sort)
-    : SyntheticSection<ELFT>(SHF_ALLOC, Config->Rela ? SHT_RELA : SHT_REL,
-                             sizeof(uintX_t), Name),
+    : SyntheticSection(SHF_ALLOC, Config->IsRela ? SHT_RELA : SHT_REL,
+                       Config->Wordsize, Name),
       Sort(Sort) {
-  this->Entsize = Config->Rela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
+  this->Entsize = Config->IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
 }
 
 template <class ELFT>
-void RelocationSection<ELFT>::addReloc(const DynamicReloc<ELFT> &Reloc) {
+void RelocationSection<ELFT>::addReloc(const DynamicReloc &Reloc) {
   if (Reloc.Type == Target->RelativeRel)
     ++NumRelativeRelocs;
   Relocs.push_back(Reloc);
@@ -990,33 +1229,33 @@ void RelocationSection<ELFT>::addReloc(const DynamicReloc<ELFT> &Reloc) {
 
 template <class ELFT, class RelTy>
 static bool compRelocations(const RelTy &A, const RelTy &B) {
-  bool AIsRel = A.getType(Config->Mips64EL) == Target->RelativeRel;
-  bool BIsRel = B.getType(Config->Mips64EL) == Target->RelativeRel;
+  bool AIsRel = A.getType(Config->IsMips64EL) == Target->RelativeRel;
+  bool BIsRel = B.getType(Config->IsMips64EL) == Target->RelativeRel;
   if (AIsRel != BIsRel)
     return AIsRel;
 
-  return A.getSymbol(Config->Mips64EL) < B.getSymbol(Config->Mips64EL);
+  return A.getSymbol(Config->IsMips64EL) < B.getSymbol(Config->IsMips64EL);
 }
 
 template <class ELFT> void RelocationSection<ELFT>::writeTo(uint8_t *Buf) {
   uint8_t *BufBegin = Buf;
-  for (const DynamicReloc<ELFT> &Rel : Relocs) {
+  for (const DynamicReloc &Rel : Relocs) {
     auto *P = reinterpret_cast<Elf_Rela *>(Buf);
-    Buf += Config->Rela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
+    Buf += Config->IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
 
-    if (Config->Rela)
+    if (Config->IsRela)
       P->r_addend = Rel.getAddend();
     P->r_offset = Rel.getOffset();
-    if (Config->EMachine == EM_MIPS && Rel.getInputSec() == In<ELFT>::MipsGot)
+    if (Config->EMachine == EM_MIPS && Rel.getInputSec() == InX::MipsGot)
       // Dynamic relocation against MIPS GOT section make deal TLS entries
       // allocated in the end of the GOT. We need to adjust the offset to take
       // in account 'local' and 'global' GOT entries.
-      P->r_offset += In<ELFT>::MipsGot->getTlsOffset();
-    P->setSymbolAndType(Rel.getSymIndex(), Rel.Type, Config->Mips64EL);
+      P->r_offset += InX::MipsGot->getTlsOffset();
+    P->setSymbolAndType(Rel.getSymIndex(), Rel.Type, Config->IsMips64EL);
   }
 
   if (Sort) {
-    if (Config->Rela)
+    if (Config->IsRela)
       std::stable_sort((Elf_Rela *)BufBegin,
                        (Elf_Rela *)BufBegin + Relocs.size(),
                        compRelocations<ELFT, Elf_Rela>);
@@ -1030,314 +1269,284 @@ template <class ELFT> unsigned RelocationSection<ELFT>::getRelocOffset() {
   return this->Entsize * Relocs.size();
 }
 
-template <class ELFT> void RelocationSection<ELFT>::finalize() {
-  this->Link = In<ELFT>::DynSymTab ? In<ELFT>::DynSymTab->OutSec->SectionIndex
-                                   : In<ELFT>::SymTab->OutSec->SectionIndex;
+template <class ELFT> void RelocationSection<ELFT>::finalizeContents() {
+  this->Link = InX::DynSymTab ? InX::DynSymTab->getParent()->SectionIndex
+                              : InX::SymTab->getParent()->SectionIndex;
 
   // Set required output section properties.
-  this->OutSec->Link = this->Link;
-  this->OutSec->Entsize = this->Entsize;
+  getParent()->Link = this->Link;
 }
 
-template <class ELFT>
-SymbolTableSection<ELFT>::SymbolTableSection(
-    StringTableSection<ELFT> &StrTabSec)
-    : SyntheticSection<ELFT>(StrTabSec.isDynamic() ? (uintX_t)SHF_ALLOC : 0,
-                             StrTabSec.isDynamic() ? SHT_DYNSYM : SHT_SYMTAB,
-                             sizeof(uintX_t),
-                             StrTabSec.isDynamic() ? ".dynsym" : ".symtab"),
-      StrTabSec(StrTabSec) {
-  this->Entsize = sizeof(Elf_Sym);
-}
+SymbolTableBaseSection::SymbolTableBaseSection(StringTableSection &StrTabSec)
+    : SyntheticSection(StrTabSec.isDynamic() ? (uint64_t)SHF_ALLOC : 0,
+                       StrTabSec.isDynamic() ? SHT_DYNSYM : SHT_SYMTAB,
+                       Config->Wordsize,
+                       StrTabSec.isDynamic() ? ".dynsym" : ".symtab"),
+      StrTabSec(StrTabSec) {}
 
 // Orders symbols according to their positions in the GOT,
 // in compliance with MIPS ABI rules.
 // 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
-static bool sortMipsSymbols(const SymbolBody *L, const SymbolBody *R) {
+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->IsInGlobalMipsGot;
-  bool RIsInLocalGot = !R->IsInGlobalMipsGot;
+  bool LIsInLocalGot = !L.Symbol->IsInGlobalMipsGot;
+  bool RIsInLocalGot = !R.Symbol->IsInGlobalMipsGot;
   if (LIsInLocalGot || RIsInLocalGot)
     return !RIsInLocalGot;
-  return L->GotIndex < R->GotIndex;
-}
-
-template <class ELFT> void SymbolTableSection<ELFT>::finalize() {
-  this->OutSec->Link = this->Link = StrTabSec.OutSec->SectionIndex;
-  this->OutSec->Info = this->Info = NumLocals + 1;
-  this->OutSec->Entsize = this->Entsize;
-
-  if (Config->Relocatable)
-    return;
+  return L.Symbol->GotIndex < R.Symbol->GotIndex;
+}
+
+// Finalize a symbol table. 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.)
+void SymbolTableBaseSection::finalizeContents() {
+  getParent()->Link = StrTabSec.getParent()->SectionIndex;
+
+  // 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);
+    }
 
-  if (!StrTabSec.isDynamic()) {
-    auto GlobBegin = Symbols.begin() + NumLocals;
-    auto It = std::stable_partition(
-        GlobBegin, Symbols.end(), [](const SymbolTableEntry &S) {
-          return S.Symbol->symbol()->computeBinding() == STB_LOCAL;
-        });
-    // update sh_info with number of Global symbols output with computed
-    // binding of STB_LOCAL
-    this->OutSec->Info = this->Info = 1 + It - Symbols.begin();
+    size_t I = 0;
+    for (const SymbolTableEntry &S : Symbols)
+      S.Symbol->DynsymIndex = ++I;
     return;
   }
-
-  if (In<ELFT>::GnuHashTab)
-    // NB: It also sorts Symbols to meet the GNU hash table requirements.
-    In<ELFT>::GnuHashTab->addSymbols(Symbols);
-  else if (Config->EMachine == EM_MIPS)
-    std::stable_sort(Symbols.begin(), Symbols.end(),
-                     [](const SymbolTableEntry &L, const SymbolTableEntry &R) {
-                       return sortMipsSymbols(L.Symbol, R.Symbol);
-                     });
-  size_t I = 0;
-  for (const SymbolTableEntry &S : Symbols)
-    S.Symbol->DynsymIndex = ++I;
 }
 
-template <class ELFT> void SymbolTableSection<ELFT>::addGlobal(SymbolBody *B) {
-  Symbols.push_back({B, StrTabSec.addString(B->getName(), false)});
+void SymbolTableBaseSection::postThunkContents() {
+  if (this->Type == SHT_DYNSYM)
+    return;
+  // move all local symbols before global symbols.
+  auto It = std::stable_partition(
+      Symbols.begin(), Symbols.end(), [](const SymbolTableEntry &S) {
+        return S.Symbol->isLocal() ||
+               S.Symbol->symbol()->computeBinding() == STB_LOCAL;
+      });
+  size_t NumLocals = It - Symbols.begin();
+  getParent()->Info = NumLocals + 1;
 }
 
-template <class ELFT> void SymbolTableSection<ELFT>::addLocal(SymbolBody *B) {
-  assert(!StrTabSec.isDynamic());
-  ++NumLocals;
-  Symbols.push_back({B, StrTabSec.addString(B->getName())});
+void SymbolTableBaseSection::addSymbol(SymbolBody *B) {
+  // Adding a local symbol to a .dynsym is a bug.
+  assert(this->Type != SHT_DYNSYM || !B->isLocal());
+
+  bool HashIt = B->isLocal();
+  Symbols.push_back({B, StrTabSec.addString(B->getName(), HashIt)});
 }
 
-template <class ELFT>
-size_t SymbolTableSection<ELFT>::getSymbolIndex(SymbolBody *Body) {
-  auto I = llvm::find_if(
-      Symbols, [&](const SymbolTableEntry &E) { return E.Symbol == Body; });
+size_t SymbolTableBaseSection::getSymbolIndex(SymbolBody *Body) {
+  auto I = llvm::find_if(Symbols, [&](const SymbolTableEntry &E) {
+    if (E.Symbol == Body)
+      return true;
+    // This is used for -r, so we have to handle multiple section
+    // symbols being combined.
+    if (Body->Type == STT_SECTION && E.Symbol->Type == STT_SECTION)
+      return Body->getOutputSection() == E.Symbol->getOutputSection();
+    return false;
+  });
   if (I == Symbols.end())
     return 0;
   return I - Symbols.begin() + 1;
 }
 
+template <class ELFT>
+SymbolTableSection<ELFT>::SymbolTableSection(StringTableSection &StrTabSec)
+    : SymbolTableBaseSection(StrTabSec) {
+  this->Entsize = sizeof(Elf_Sym);
+}
+
+// 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.
   Buf += sizeof(Elf_Sym);
 
-  // All symbols with STB_LOCAL binding precede the weak and global symbols.
-  // .dynsym only contains global symbols.
-  if (Config->Discard != DiscardPolicy::All && !StrTabSec.isDynamic())
-    writeLocalSymbols(Buf);
-
-  writeGlobalSymbols(Buf);
-}
-
-template <class ELFT>
-void SymbolTableSection<ELFT>::writeLocalSymbols(uint8_t *&Buf) {
-  // Iterate over all input object files to copy their local symbols
-  // to the output symbol table pointed by Buf.
+  auto *ESym = reinterpret_cast<Elf_Sym *>(Buf);
 
-  for (auto I = Symbols.begin(); I != Symbols.begin() + NumLocals; ++I) {
-    const DefinedRegular<ELFT> &Body = *cast<DefinedRegular<ELFT>>(I->Symbol);
-    InputSectionBase<ELFT> *Section = Body.Section;
-    auto *ESym = reinterpret_cast<Elf_Sym *>(Buf);
+  for (SymbolTableEntry &Ent : Symbols) {
+    SymbolBody *Body = Ent.Symbol;
 
-    if (!Section) {
-      ESym->st_shndx = SHN_ABS;
-      ESym->st_value = Body.Value;
+    // Set st_info and st_other.
+    if (Body->isLocal()) {
+      ESym->setBindingAndType(STB_LOCAL, Body->Type);
     } else {
-      const OutputSectionBase *OutSec = Section->OutSec;
-      ESym->st_shndx = OutSec->SectionIndex;
-      ESym->st_value = OutSec->Addr + Section->getOffset(Body);
+      ESym->setBindingAndType(Body->symbol()->computeBinding(), Body->Type);
+      ESym->setVisibility(Body->symbol()->Visibility);
     }
-    ESym->st_name = I->StrTabOffset;
-    ESym->st_size = Body.template getSize<ELFT>();
-    ESym->setBindingAndType(STB_LOCAL, Body.Type);
-    Buf += sizeof(*ESym);
-  }
-}
-
-template <class ELFT>
-void SymbolTableSection<ELFT>::writeGlobalSymbols(uint8_t *Buf) {
-  // Write the internal symbol table contents to the output symbol table
-  // pointed by Buf.
-  auto *ESym = reinterpret_cast<Elf_Sym *>(Buf);
-
-  for (auto I = Symbols.begin() + NumLocals; I != Symbols.end(); ++I) {
-    const SymbolTableEntry &S = *I;
-    SymbolBody *Body = S.Symbol;
-    size_t StrOff = S.StrTabOffset;
 
-    uint8_t Type = Body->Type;
-    uintX_t Size = Body->getSize<ELFT>();
+    ESym->st_name = Ent.StrTabOffset;
 
-    ESym->setBindingAndType(Body->symbol()->computeBinding(), Type);
-    ESym->st_size = Size;
-    ESym->st_name = StrOff;
-    ESym->setVisibility(Body->symbol()->Visibility);
-    ESym->st_value = Body->getVA<ELFT>();
-
-    if (const OutputSectionBase *OutSec = getOutputSection(Body)) {
+    // Set a section index.
+    if (const OutputSection *OutSec = Body->getOutputSection())
       ESym->st_shndx = OutSec->SectionIndex;
-    } else if (isa<DefinedRegular<ELFT>>(Body)) {
+    else if (isa<DefinedRegular>(Body))
       ESym->st_shndx = SHN_ABS;
-    } else if (isa<DefinedCommon>(Body)) {
+    else if (isa<DefinedCommon>(Body))
       ESym->st_shndx = SHN_COMMON;
+
+    // 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
+    // the case. We'll leave it as zero because by not setting a value, we can
+    // get the exact same outputs for two sets of input files that differ only
+    // in undefined symbol size in DSOs.
+    if (ESym->st_shndx != SHN_UNDEF)
+      ESym->st_size = Body->getSize<ELFT>();
+
+    // 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 (!Config->DefineCommon && isa<DefinedCommon>(Body))
       ESym->st_value = cast<DefinedCommon>(Body)->Alignment;
-    }
+    else
+      ESym->st_value = Body->getVA();
 
-    if (Config->EMachine == EM_MIPS) {
-      // On MIPS we need to mark symbol which has a PLT entry and requires
-      // pointer equality by STO_MIPS_PLT flag. That is necessary to help
-      // dynamic linker distinguish such symbols and MIPS lazy-binding stubs.
-      // https://sourceware.org/ml/binutils/2008-07/txt00000.txt
-      if (Body->isInPlt() && Body->NeedsCopyOrPltAddr)
-        ESym->st_other |= STO_MIPS_PLT;
-      if (Config->Relocatable) {
-        auto *D = dyn_cast<DefinedRegular<ELFT>>(Body);
-        if (D && D->isMipsPIC())
-          ESym->st_other |= STO_MIPS_PIC;
-      }
-    }
     ++ESym;
   }
-}
 
-template <class ELFT>
-const OutputSectionBase *
-SymbolTableSection<ELFT>::getOutputSection(SymbolBody *Sym) {
-  switch (Sym->kind()) {
-  case SymbolBody::DefinedSyntheticKind:
-    return cast<DefinedSynthetic>(Sym)->Section;
-  case SymbolBody::DefinedRegularKind: {
-    auto &D = cast<DefinedRegular<ELFT>>(*Sym);
-    if (D.Section)
-      return D.Section->OutSec;
-    break;
-  }
-  case SymbolBody::DefinedCommonKind:
-    if (!Config->DefineCommon)
-      return nullptr;
-    return In<ELFT>::Common->OutSec;
-  case SymbolBody::SharedKind: {
-    auto &SS = cast<SharedSymbol<ELFT>>(*Sym);
-    if (SS.needsCopy())
-      return SS.getBssSectionForCopy();
-    break;
-  }
-  case SymbolBody::UndefinedKind:
-  case SymbolBody::LazyArchiveKind:
-  case SymbolBody::LazyObjectKind:
-    break;
-  }
-  return nullptr;
-}
-
-template <class ELFT>
-GnuHashTableSection<ELFT>::GnuHashTableSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC, SHT_GNU_HASH, sizeof(uintX_t),
-                             ".gnu.hash") {
-  this->Entsize = ELFT::Is64Bits ? 0 : 4;
-}
-
-template <class ELFT>
-unsigned GnuHashTableSection<ELFT>::calcNBuckets(unsigned NumHashed) {
-  if (!NumHashed)
-    return 0;
-
-  // These values are prime numbers which are not greater than 2^(N-1) + 1.
-  // In result, for any particular NumHashed we return a prime number
-  // which is not greater than NumHashed.
-  static const unsigned Primes[] = {
-      1,   1,    3,    3,    7,    13,    31,    61,    127,   251,
-      509, 1021, 2039, 4093, 8191, 16381, 32749, 65521, 131071};
-
-  return Primes[std::min<unsigned>(Log2_32_Ceil(NumHashed),
-                                   array_lengthof(Primes) - 1)];
-}
-
-// Bloom filter estimation: at least 8 bits for each hashed symbol.
-// GNU Hash table requirement: it should be a power of 2,
-//   the minimum value is 1, even for an empty table.
-// Expected results for a 32-bit target:
-//   calcMaskWords(0..4)   = 1
-//   calcMaskWords(5..8)   = 2
-//   calcMaskWords(9..16)  = 4
-// For a 64-bit target:
-//   calcMaskWords(0..8)   = 1
-//   calcMaskWords(9..16)  = 2
-//   calcMaskWords(17..32) = 4
-template <class ELFT>
-unsigned GnuHashTableSection<ELFT>::calcMaskWords(unsigned NumHashed) {
-  if (!NumHashed)
-    return 1;
-  return NextPowerOf2((NumHashed - 1) / sizeof(Elf_Off));
-}
+  // On MIPS we need to mark symbol which has a PLT entry and requires
+  // pointer equality by STO_MIPS_PLT flag. That is necessary to help
+  // dynamic linker distinguish such symbols and MIPS lazy-binding stubs.
+  // https://sourceware.org/ml/binutils/2008-07/txt00000.txt
+  if (Config->EMachine == EM_MIPS) {
+    auto *ESym = reinterpret_cast<Elf_Sym *>(Buf);
 
-template <class ELFT> void GnuHashTableSection<ELFT>::finalize() {
-  unsigned NumHashed = Symbols.size();
-  NBuckets = calcNBuckets(NumHashed);
-  MaskWords = calcMaskWords(NumHashed);
-  // Second hash shift estimation: just predefined values.
-  Shift2 = ELFT::Is64Bits ? 6 : 5;
+    for (SymbolTableEntry &Ent : Symbols) {
+      SymbolBody *Body = Ent.Symbol;
+      if (Body->isInPlt() && Body->NeedsPltAddr)
+        ESym->st_other |= STO_MIPS_PLT;
 
-  this->OutSec->Entsize = this->Entsize;
-  this->OutSec->Link = this->Link = In<ELFT>::DynSymTab->OutSec->SectionIndex;
-  this->Size = sizeof(Elf_Word) * 4            // Header
-               + sizeof(Elf_Off) * MaskWords   // Bloom Filter
-               + sizeof(Elf_Word) * NBuckets   // Hash Buckets
-               + sizeof(Elf_Word) * NumHashed; // Hash Values
+      if (Config->Relocatable)
+        if (auto *D = dyn_cast<DefinedRegular>(Body))
+          if (D->isMipsPIC<ELFT>())
+            ESym->st_other |= STO_MIPS_PIC;
+      ++ESym;
+    }
+  }
 }
 
-template <class ELFT> void GnuHashTableSection<ELFT>::writeTo(uint8_t *Buf) {
-  writeHeader(Buf);
+// .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
+// don't have them, the dynamic linker has to do linear search on all
+// dynamic symbols, which makes programs slower. Therefore, a .hash
+// section is added to a DSO by default. A .gnu.hash is added if you
+// give the -hash-style=gnu or -hash-style=both option.
+//
+// The Unix semantics of resolving dynamic symbols is somewhat expensive.
+// Each ELF file has a list of DSOs that the ELF file depends on and a
+// list of dynamic symbols that need to be resolved from any of the
+// DSOs. That means resolving all dynamic symbols takes O(m)*O(n)
+// where m is the number of DSOs and n is the number of dynamic
+// symbols. For modern large programs, both m and n are large.  So
+// making each step faster by using hash tables substiantially
+// improves time to load programs.
+//
+// (Note that this is not the only way to design the shared library.
+// For instance, the Windows DLL takes a different approach. On
+// Windows, each dynamic symbol has a name of DLL from which the symbol
+// has to be resolved. That makes the cost of symbol resolution O(n).
+// This disables some hacky techniques you can use on Unix such as
+// LD_PRELOAD, but this is arguably better semantics than the Unix ones.)
+//
+// Due to historical reasons, we have two different hash tables, .hash
+// and .gnu.hash. They are for the same purpose, and .gnu.hash is a new
+// and better version of .hash. .hash is just an on-disk hash table, but
+// .gnu.hash has a bloom filter in addition to a hash table to skip
+// DSOs very quickly. If you are sure that your dynamic linker knows
+// about .gnu.hash, you want to specify -hash-style=gnu. Otherwise, a
+// safe bet is to specify -hash-style=both for backward compatibilty.
+GnuHashTableSection::GnuHashTableSection()
+    : SyntheticSection(SHF_ALLOC, SHT_GNU_HASH, Config->Wordsize, ".gnu.hash") {
+}
+
+void GnuHashTableSection::finalizeContents() {
+  getParent()->Link = InX::DynSymTab->getParent()->SectionIndex;
+
+  // Computes bloom filter size in word size. We want to allocate 8
+  // bits for each symbol. It must be a power of two.
   if (Symbols.empty())
-    return;
+    MaskWords = 1;
+  else
+    MaskWords = NextPowerOf2((Symbols.size() - 1) / Config->Wordsize);
+
+  Size = 16;                            // Header
+  Size += Config->Wordsize * MaskWords; // Bloom filter
+  Size += NBuckets * 4;                 // Hash buckets
+  Size += Symbols.size() * 4;           // Hash values
+}
+
+void GnuHashTableSection::writeTo(uint8_t *Buf) {
+  // Write a header.
+  write32(Buf, NBuckets, Config->Endianness);
+  write32(Buf + 4, InX::DynSymTab->getNumSymbols() - Symbols.size(),
+          Config->Endianness);
+  write32(Buf + 8, MaskWords, Config->Endianness);
+  write32(Buf + 12, getShift2(), Config->Endianness);
+  Buf += 16;
+
+  // Write a bloom filter and a hash table.
   writeBloomFilter(Buf);
+  Buf += Config->Wordsize * MaskWords;
   writeHashTable(Buf);
 }
 
-template <class ELFT>
-void GnuHashTableSection<ELFT>::writeHeader(uint8_t *&Buf) {
-  auto *P = reinterpret_cast<Elf_Word *>(Buf);
-  *P++ = NBuckets;
-  *P++ = In<ELFT>::DynSymTab->getNumSymbols() - Symbols.size();
-  *P++ = MaskWords;
-  *P++ = Shift2;
-  Buf = reinterpret_cast<uint8_t *>(P);
-}
-
-template <class ELFT>
-void GnuHashTableSection<ELFT>::writeBloomFilter(uint8_t *&Buf) {
-  unsigned C = sizeof(Elf_Off) * 8;
-
-  auto *Masks = reinterpret_cast<Elf_Off *>(Buf);
-  for (const SymbolData &Sym : Symbols) {
-    size_t Pos = (Sym.Hash / C) & (MaskWords - 1);
-    uintX_t V = (uintX_t(1) << (Sym.Hash % C)) |
-                (uintX_t(1) << ((Sym.Hash >> Shift2) % C));
-    Masks[Pos] |= V;
+// This function writes a 2-bit bloom filter. This bloom filter alone
+// usually filters out 80% or more of all symbol lookups [1].
+// The dynamic linker uses the hash table only when a symbol is not
+// filtered out by a bloom filter.
+//
+// [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;
+  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);
+    writeUint(Buf + I * Config->Wordsize, Val);
   }
-  Buf += sizeof(Elf_Off) * MaskWords;
 }
 
-template <class ELFT>
-void GnuHashTableSection<ELFT>::writeHashTable(uint8_t *Buf) {
-  Elf_Word *Buckets = reinterpret_cast<Elf_Word *>(Buf);
-  Elf_Word *Values = Buckets + NBuckets;
-
-  int PrevBucket = -1;
-  int I = 0;
-  for (const SymbolData &Sym : Symbols) {
-    int Bucket = Sym.Hash % NBuckets;
-    assert(PrevBucket <= Bucket);
-    if (Bucket != PrevBucket) {
-      Buckets[Bucket] = Sym.Body->DynsymIndex;
-      PrevBucket = Bucket;
-      if (I > 0)
-        Values[I - 1] |= 1;
-    }
-    Values[I] = Sym.Hash & ~1;
-    ++I;
+void GnuHashTableSection::writeHashTable(uint8_t *Buf) {
+  // Group symbols by hash value.
+  std::vector<std::vector<Entry>> Syms(NBuckets);
+  for (const Entry &Ent : Symbols)
+    Syms[Ent.Hash % NBuckets].push_back(Ent);
+
+  // Write hash buckets. Hash buckets contain indices in the following
+  // hash value table.
+  uint32_t *Buckets = reinterpret_cast<uint32_t *>(Buf);
+  for (size_t I = 0; I < NBuckets; ++I)
+    if (!Syms[I].empty())
+      write32(Buckets + I, Syms[I][0].Body->DynsymIndex, Config->Endianness);
+
+  // Write a hash value table. It represents a sequence of chains that
+  // share the same hash modulo value. The last element of each chain
+  // is terminated by LSB 1.
+  uint32_t *Values = Buckets + NBuckets;
+  size_t I = 0;
+  for (std::vector<Entry> &Vec : Syms) {
+    if (Vec.empty())
+      continue;
+    for (const Entry &Ent : makeArrayRef(Vec).drop_back())
+      write32(Values + I++, Ent.Hash & ~1, Config->Endianness);
+    write32(Values + I++, Vec.back().Hash | 1, Config->Endianness);
   }
-  if (I > 0)
-    Values[I - 1] |= 1;
 }
 
 static uint32_t hashGnu(StringRef Name) {
@@ -1347,58 +1556,76 @@ static uint32_t hashGnu(StringRef Name) {
   return H;
 }
 
+// Returns a number of hash buckets to accomodate given number of elements.
+// We want to choose a moderate number that is not too small (which
+// causes too many hash collisions) and not too large (which wastes
+// disk space.)
+//
+// We return a prime number because it (is believed to) achieve good
+// hash distribution.
+static size_t getBucketSize(size_t NumSymbols) {
+  // List of largest prime numbers that are not greater than 2^n + 1.
+  for (size_t N : {131071, 65521, 32749, 16381, 8191, 4093, 2039, 1021, 509,
+                   251, 127, 61, 31, 13, 7, 3, 1})
+    if (N <= NumSymbols)
+      return N;
+  return 0;
+}
+
 // Add symbols to this symbol hash table. Note that this function
 // destructively sort a given vector -- which is needed because
 // GNU-style hash table places some sorting requirements.
-template <class ELFT>
-void GnuHashTableSection<ELFT>::addSymbols(std::vector<SymbolTableEntry> &V) {
-  // Ideally this will just be 'auto' but GCC 6.1 is not able
-  // to deduce it correctly.
+void GnuHashTableSection::addSymbols(std::vector<SymbolTableEntry> &V) {
+  // We cannot use 'auto' for Mid because GCC 6.1 cannot deduce
+  // its type correctly.
   std::vector<SymbolTableEntry>::iterator Mid =
       std::stable_partition(V.begin(), V.end(), [](const SymbolTableEntry &S) {
         return S.Symbol->isUndefined();
       });
   if (Mid == V.end())
     return;
-  for (auto I = Mid, E = V.end(); I != E; ++I) {
-    SymbolBody *B = I->Symbol;
-    size_t StrOff = I->StrTabOffset;
-    Symbols.push_back({B, StrOff, hashGnu(B->getName())});
+
+  for (SymbolTableEntry &Ent : llvm::make_range(Mid, V.end())) {
+    SymbolBody *B = Ent.Symbol;
+    Symbols.push_back({B, Ent.StrTabOffset, hashGnu(B->getName())});
   }
 
-  unsigned NBuckets = calcNBuckets(Symbols.size());
+  NBuckets = getBucketSize(Symbols.size());
   std::stable_sort(Symbols.begin(), Symbols.end(),
-                   [&](const SymbolData &L, const SymbolData &R) {
+                   [&](const Entry &L, const Entry &R) {
                      return L.Hash % NBuckets < R.Hash % NBuckets;
                    });
 
   V.erase(Mid, V.end());
-  for (const SymbolData &Sym : Symbols)
-    V.push_back({Sym.Body, Sym.STName});
+  for (const Entry &Ent : Symbols)
+    V.push_back({Ent.Body, Ent.StrTabOffset});
 }
 
 template <class ELFT>
 HashTableSection<ELFT>::HashTableSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC, SHT_HASH, sizeof(Elf_Word), ".hash") {
-  this->Entsize = sizeof(Elf_Word);
+    : SyntheticSection(SHF_ALLOC, SHT_HASH, 4, ".hash") {
+  this->Entsize = 4;
 }
 
-template <class ELFT> void HashTableSection<ELFT>::finalize() {
-  this->OutSec->Link = this->Link = In<ELFT>::DynSymTab->OutSec->SectionIndex;
-  this->OutSec->Entsize = this->Entsize;
+template <class ELFT> void HashTableSection<ELFT>::finalizeContents() {
+  getParent()->Link = InX::DynSymTab->getParent()->SectionIndex;
 
-  unsigned NumEntries = 2;                            // nbucket and nchain.
-  NumEntries += In<ELFT>::DynSymTab->getNumSymbols(); // The chain entries.
+  unsigned NumEntries = 2;                       // nbucket and nchain.
+  NumEntries += InX::DynSymTab->getNumSymbols(); // The chain entries.
 
   // Create as many buckets as there are symbols.
   // FIXME: This is simplistic. We can try to optimize it, but implementing
   // support for SHT_GNU_HASH is probably even more profitable.
-  NumEntries += In<ELFT>::DynSymTab->getNumSymbols();
-  this->Size = NumEntries * sizeof(Elf_Word);
+  NumEntries += InX::DynSymTab->getNumSymbols();
+  this->Size = NumEntries * 4;
 }
 
 template <class ELFT> void HashTableSection<ELFT>::writeTo(uint8_t *Buf) {
-  unsigned NumSymbols = In<ELFT>::DynSymTab->getNumSymbols();
+  // A 32-bit integer type in the target endianness.
+  typedef typename ELFT::Word Elf_Word;
+
+  unsigned NumSymbols = InX::DynSymTab->getNumSymbols();
+
   auto *P = reinterpret_cast<Elf_Word *>(Buf);
   *P++ = NumSymbols; // nbucket
   *P++ = NumSymbols; // nchain
@@ -1406,7 +1633,7 @@ template <class ELFT> void HashTableSection<ELFT>::writeTo(uint8_t *Buf) {
   Elf_Word *Buckets = P;
   Elf_Word *Chains = P + NumSymbols;
 
-  for (const SymbolTableEntry &S : In<ELFT>::DynSymTab->getSymbols()) {
+  for (const SymbolTableEntry &S : InX::DynSymTab->getSymbols()) {
     SymbolBody *Body = S.Symbol;
     StringRef Name = Body->getName();
     unsigned I = Body->DynsymIndex;
@@ -1416,78 +1643,69 @@ template <class ELFT> void HashTableSection<ELFT>::writeTo(uint8_t *Buf) {
   }
 }
 
-template <class ELFT>
-PltSection<ELFT>::PltSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS, 16,
-                             ".plt") {}
+PltSection::PltSection(size_t S)
+    : SyntheticSection(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS, 16, ".plt"),
+      HeaderSize(S) {
+  // 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)
+    this->Flags |= SHF_WRITE;
+}
 
-template <class ELFT> void PltSection<ELFT>::writeTo(uint8_t *Buf) {
-  // At beginning of PLT, we have code to call the dynamic linker
-  // to resolve dynsyms at runtime. Write such code.
-  Target->writePltHeader(Buf);
-  size_t Off = Target->PltHeaderSize;
+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)
+    Target->writePltHeader(Buf);
+  size_t Off = HeaderSize;
+  // The IPlt is immediately after the Plt, account for this in RelOff
+  unsigned PltOff = getPltRelocOff();
 
   for (auto &I : Entries) {
     const SymbolBody *B = I.first;
-    unsigned RelOff = I.second;
-    uint64_t Got = B->getGotPltVA<ELFT>();
+    unsigned RelOff = I.second + PltOff;
+    uint64_t Got = B->getGotPltVA();
     uint64_t Plt = this->getVA() + Off;
     Target->writePlt(Buf + Off, Got, Plt, B->PltIndex, RelOff);
     Off += Target->PltEntrySize;
   }
 }
 
-template <class ELFT> void PltSection<ELFT>::addEntry(SymbolBody &Sym) {
+template <class ELFT> void PltSection::addEntry(SymbolBody &Sym) {
   Sym.PltIndex = Entries.size();
-  unsigned RelOff = In<ELFT>::RelaPlt->getRelocOffset();
+  RelocationSection<ELFT> *PltRelocSection = In<ELFT>::RelaPlt;
+  if (HeaderSize == 0) {
+    PltRelocSection = In<ELFT>::RelaIplt;
+    Sym.IsInIplt = true;
+  }
+  unsigned RelOff = PltRelocSection->getRelocOffset();
   Entries.push_back(std::make_pair(&Sym, RelOff));
 }
 
-template <class ELFT> size_t PltSection<ELFT>::getSize() const {
-  return Target->PltHeaderSize + Entries.size() * Target->PltEntrySize;
+size_t PltSection::getSize() const {
+  return HeaderSize + Entries.size() * Target->PltEntrySize;
 }
 
-template <class ELFT>
-IpltSection<ELFT>::IpltSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS, 16,
-                             ".plt") {}
-
-template <class ELFT> void IpltSection<ELFT>::writeTo(uint8_t *Buf) {
-  // The IRelative relocations do not support lazy binding so no header is
-  // needed
-  size_t Off = 0;
-  for (auto &I : Entries) {
-    const SymbolBody *B = I.first;
-    unsigned RelOff = I.second + In<ELFT>::Plt->getSize();
-    uint64_t Got = B->getGotPltVA<ELFT>();
-    uint64_t Plt = this->getVA() + Off;
-    Target->writePlt(Buf + Off, Got, Plt, B->PltIndex, RelOff);
+// Some architectures such as additional symbols in the PLT section. For
+// 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)
+    Target->addPltHeaderSymbols(this);
+  size_t Off = HeaderSize;
+  for (size_t I = 0; I < Entries.size(); ++I) {
+    Target->addPltSymbols(this, Off);
     Off += Target->PltEntrySize;
   }
 }
 
-template <class ELFT> void IpltSection<ELFT>::addEntry(SymbolBody &Sym) {
-  Sym.PltIndex = Entries.size();
-  Sym.IsInIplt = true;
-  unsigned RelOff = In<ELFT>::RelaIplt->getRelocOffset();
-  Entries.push_back(std::make_pair(&Sym, RelOff));
+unsigned PltSection::getPltRelocOff() const {
+  return (HeaderSize == 0) ? InX::Plt->getSize() : 0;
 }
 
-template <class ELFT> size_t IpltSection<ELFT>::getSize() const {
-  return Entries.size() * Target->PltEntrySize;
-}
-
-template <class ELFT>
-GdbIndexSection<ELFT>::GdbIndexSection()
-    : SyntheticSection<ELFT>(0, SHT_PROGBITS, 1, ".gdb_index"),
-      StringPool(llvm::StringTableBuilder::ELF) {}
-
-template <class ELFT> void GdbIndexSection<ELFT>::parseDebugSections() {
-  for (InputSectionBase<ELFT> *S : Symtab<ELFT>::X->Sections)
-    if (InputSection<ELFT> *IS = dyn_cast<InputSection<ELFT>>(S))
-      if (IS->OutSec && IS->Name == ".debug_info")
-        readDwarf(IS);
-}
+GdbIndexSection::GdbIndexSection(std::vector<GdbIndexChunk> &&Chunks)
+    : SyntheticSection(0, SHT_PROGBITS, 1, ".gdb_index"),
+      StringPool(llvm::StringTableBuilder::ELF), Chunks(std::move(Chunks)) {}
 
 // Iterative hash function for symbol's name is described in .gdb_index format
 // specification. Note that we use one for version 5 to 7 here, it is different
@@ -1499,57 +1717,149 @@ static uint32_t hash(StringRef Str) {
   return R;
 }
 
-template <class ELFT>
-void GdbIndexSection<ELFT>::readDwarf(InputSection<ELFT> *I) {
-  GdbIndexBuilder<ELFT> Builder(I);
-  if (ErrorCount)
-    return;
+static std::vector<CompilationUnitEntry> readCuList(DWARFContext &Dwarf) {
+  std::vector<CompilationUnitEntry> Ret;
+  for (std::unique_ptr<DWARFCompileUnit> &CU : Dwarf.compile_units())
+    Ret.push_back({CU->getOffset(), CU->getLength() + 4});
+  return Ret;
+}
+
+static std::vector<AddressEntry> readAddressArea(DWARFContext &Dwarf,
+                                                 InputSection *Sec) {
+  std::vector<AddressEntry> Ret;
+
+  uint32_t CurrentCu = 0;
+  for (std::unique_ptr<DWARFCompileUnit> &CU : Dwarf.compile_units()) {
+    DWARFAddressRangesVector Ranges;
+    CU->collectAddressRanges(Ranges);
+
+    ArrayRef<InputSectionBase *> Sections = Sec->File->getSections();
+    for (DWARFAddressRange &R : Ranges) {
+      InputSectionBase *S = Sections[R.SectionIndex];
+      if (!S || S == &InputSection::Discarded || !S->Live)
+        continue;
+      // Range list with zero size has no effect.
+      if (R.LowPC == R.HighPC)
+        continue;
+      Ret.push_back({cast<InputSection>(S), R.LowPC, R.HighPC, CurrentCu});
+    }
+    ++CurrentCu;
+  }
+  return Ret;
+}
+
+static std::vector<NameTypeEntry> readPubNamesAndTypes(DWARFContext &Dwarf,
+                                                       bool IsLE) {
+  StringRef Data[] = {Dwarf.getGnuPubNamesSection(),
+                      Dwarf.getGnuPubTypesSection()};
 
-  size_t CuId = CompilationUnits.size();
-  std::vector<std::pair<uintX_t, uintX_t>> CuList = Builder.readCUList();
-  CompilationUnits.insert(CompilationUnits.end(), CuList.begin(), CuList.end());
+  std::vector<NameTypeEntry> Ret;
+  for (StringRef D : Data) {
+    DWARFDebugPubTable PubTable(D, IsLE, true);
+    for (const DWARFDebugPubTable::Set &Set : PubTable.getData())
+      for (const DWARFDebugPubTable::Entry &Ent : Set.Entries)
+        Ret.push_back({Ent.Name, Ent.Descriptor.toBits()});
+  }
+  return Ret;
+}
 
-  std::vector<AddressEntry<ELFT>> AddrArea = Builder.readAddressArea(CuId);
-  AddressArea.insert(AddressArea.end(), AddrArea.begin(), AddrArea.end());
+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;
+}
 
-  std::vector<std::pair<StringRef, uint8_t>> NamesAndTypes =
-      Builder.readPubNamesAndTypes();
+void GdbIndexSection::buildIndex() {
+  if (Chunks.empty())
+    return;
 
-  for (std::pair<StringRef, uint8_t> &Pair : NamesAndTypes) {
-    uint32_t Hash = hash(Pair.first);
-    size_t Offset = StringPool.add(Pair.first);
+  uint32_t CuId = 0;
+  for (GdbIndexChunk &D : Chunks) {
+    for (AddressEntry &E : D.AddressArea)
+      E.CuIndex += CuId;
+
+    // Populate constant pool area.
+    for (NameTypeEntry &NameType : D.NamesAndTypes) {
+      uint32_t Hash = hash(NameType.Name);
+      size_t Offset = StringPool.add(NameType.Name);
+
+      bool IsNew;
+      GdbSymbol *Sym;
+      std::tie(IsNew, Sym) = SymbolTable.add(Hash, Offset);
+      if (IsNew) {
+        Sym->CuVectorIndex = CuVectors.size();
+        CuVectors.resize(CuVectors.size() + 1);
+      }
 
-    bool IsNew;
-    GdbSymbol *Sym;
-    std::tie(IsNew, Sym) = SymbolTable.add(Hash, Offset);
-    if (IsNew) {
-      Sym->CuVectorIndex = CuVectors.size();
-      CuVectors.push_back({{CuId, Pair.second}});
-      continue;
+      CuVectors[Sym->CuVectorIndex].insert(CuId | (NameType.Type << 24));
     }
 
-    std::vector<std::pair<uint32_t, uint8_t>> &CuVec =
-        CuVectors[Sym->CuVectorIndex];
-    CuVec.push_back({CuId, Pair.second});
+    CuId += D.CompilationUnits.size();
+  }
+}
+
+static GdbIndexChunk readDwarf(DWARFContextInMemory &Dwarf, InputSection *Sec) {
+  GdbIndexChunk Ret;
+  Ret.DebugInfoSec = Sec;
+  Ret.CompilationUnits = readCuList(Dwarf);
+  Ret.AddressArea = readAddressArea(Dwarf, Sec);
+  Ret.NamesAndTypes = readPubNamesAndTypes(Dwarf, Config->IsLE);
+  return Ret;
+}
+
+template <class ELFT> GdbIndexSection *elf::createGdbIndex() {
+  std::vector<GdbIndexChunk> Chunks;
+  for (InputSection *Sec : getDebugInfoSections()) {
+    InputFile *F = Sec->File;
+    std::error_code EC;
+    ELFObjectFile<ELFT> Obj(F->MB, EC);
+    if (EC)
+      fatal(EC.message());
+    DWARFContextInMemory Dwarf(Obj, nullptr, [&](Error E) {
+      error(toString(F) + ": error parsing DWARF data:\n>>> " +
+            toString(std::move(E)));
+      return ErrorPolicy::Continue;
+    });
+    Chunks.push_back(readDwarf(Dwarf, Sec));
   }
+  return make<GdbIndexSection>(std::move(Chunks));
+}
+
+static size_t getCuSize(std::vector<GdbIndexChunk> &C) {
+  size_t Ret = 0;
+  for (GdbIndexChunk &D : C)
+    Ret += D.CompilationUnits.size();
+  return Ret;
 }
 
-template <class ELFT> void GdbIndexSection<ELFT>::finalize() {
+static size_t getAddressAreaSize(std::vector<GdbIndexChunk> &C) {
+  size_t Ret = 0;
+  for (GdbIndexChunk &D : C)
+    Ret += D.AddressArea.size();
+  return Ret;
+}
+
+void GdbIndexSection::finalizeContents() {
   if (Finalized)
     return;
   Finalized = true;
 
-  parseDebugSections();
+  buildIndex();
+
+  SymbolTable.finalizeContents();
 
   // GdbIndex header consist from version fields
   // and 5 more fields with different kinds of offsets.
-  CuTypesOffset = CuListOffset + CompilationUnits.size() * CompilationUnitSize;
-  SymTabOffset = CuTypesOffset + AddressArea.size() * AddressEntrySize;
+  CuTypesOffset = CuListOffset + getCuSize(Chunks) * CompilationUnitSize;
+  SymTabOffset = CuTypesOffset + getAddressAreaSize(Chunks) * AddressEntrySize;
 
   ConstantPoolOffset =
       SymTabOffset + SymbolTable.getCapacity() * SymTabEntrySize;
 
-  for (std::vector<std::pair<uint32_t, uint8_t>> &CuVec : CuVectors) {
+  for (std::set<uint32_t> &CuVec : CuVectors) {
     CuVectorsOffset.push_back(CuVectorsSize);
     CuVectorsSize += OffsetTypeSize * (CuVec.size() + 1);
   }
@@ -1558,12 +1868,12 @@ template <class ELFT> void GdbIndexSection<ELFT>::finalize() {
   StringPool.finalizeInOrder();
 }
 
-template <class ELFT> size_t GdbIndexSection<ELFT>::getSize() const {
-  const_cast<GdbIndexSection<ELFT> *>(this)->finalize();
+size_t GdbIndexSection::getSize() const {
+  const_cast<GdbIndexSection *>(this)->finalizeContents();
   return StringPoolOffset + StringPool.getSize();
 }
 
-template <class ELFT> void GdbIndexSection<ELFT>::writeTo(uint8_t *Buf) {
+void GdbIndexSection::writeTo(uint8_t *Buf) {
   write32le(Buf, 7);                       // Write version.
   write32le(Buf + 4, CuListOffset);        // CU list offset.
   write32le(Buf + 8, CuTypesOffset);       // Types CU list offset.
@@ -1573,19 +1883,24 @@ template <class ELFT> void GdbIndexSection<ELFT>::writeTo(uint8_t *Buf) {
   Buf += 24;
 
   // Write the CU list.
-  for (std::pair<uintX_t, uintX_t> CU : CompilationUnits) {
-    write64le(Buf, CU.first);
-    write64le(Buf + 8, CU.second);
-    Buf += 16;
+  for (GdbIndexChunk &D : Chunks) {
+    for (CompilationUnitEntry &Cu : D.CompilationUnits) {
+      write64le(Buf, D.DebugInfoSec->OutSecOff + Cu.CuOffset);
+      write64le(Buf + 8, Cu.CuLength);
+      Buf += 16;
+    }
   }
 
   // Write the address area.
-  for (AddressEntry<ELFT> &E : AddressArea) {
-    uintX_t BaseAddr = E.Section->OutSec->Addr + E.Section->getOffset(0);
-    write64le(Buf, BaseAddr + E.LowAddress);
-    write64le(Buf + 8, BaseAddr + E.HighAddress);
-    write32le(Buf + 16, E.CuIndex);
-    Buf += 20;
+  for (GdbIndexChunk &D : Chunks) {
+    for (AddressEntry &E : D.AddressArea) {
+      uint64_t BaseAddr =
+          E.Section->getParent()->Addr + E.Section->getOffset(0);
+      write64le(Buf, BaseAddr + E.LowAddress);
+      write64le(Buf + 8, BaseAddr + E.HighAddress);
+      write32le(Buf + 16, E.CuIndex);
+      Buf += 20;
+    }
   }
 
   // Write the symbol table.
@@ -1602,14 +1917,11 @@ template <class ELFT> void GdbIndexSection<ELFT>::writeTo(uint8_t *Buf) {
   }
 
   // Write the CU vectors into the constant pool.
-  for (std::vector<std::pair<uint32_t, uint8_t>> &CuVec : CuVectors) {
+  for (std::set<uint32_t> &CuVec : CuVectors) {
     write32le(Buf, CuVec.size());
     Buf += 4;
-    for (std::pair<uint32_t, uint8_t> &P : CuVec) {
-      uint32_t Index = P.first;
-      uint8_t Flags = P.second;
-      Index |= Flags << 24;
-      write32le(Buf, Index);
+    for (uint32_t Val : CuVec) {
+      write32le(Buf, Val);
       Buf += 4;
     }
   }
@@ -1617,13 +1929,11 @@ template <class ELFT> void GdbIndexSection<ELFT>::writeTo(uint8_t *Buf) {
   StringPool.write(Buf);
 }
 
-template <class ELFT> bool GdbIndexSection<ELFT>::empty() const {
-  return !Out<ELFT>::DebugInfo;
-}
+bool GdbIndexSection::empty() const { return !Out::DebugInfo; }
 
 template <class ELFT>
 EhFrameHeader<ELFT>::EhFrameHeader()
-    : SyntheticSection<ELFT>(SHF_ALLOC, SHT_PROGBITS, 1, ".eh_frame_hdr") {}
+    : SyntheticSection(SHF_ALLOC, SHT_PROGBITS, 1, ".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,
@@ -1644,11 +1954,11 @@ template <class ELFT> void EhFrameHeader<ELFT>::writeTo(uint8_t *Buf) {
   Buf[1] = DW_EH_PE_pcrel | DW_EH_PE_sdata4;
   Buf[2] = DW_EH_PE_udata4;
   Buf[3] = DW_EH_PE_datarel | DW_EH_PE_sdata4;
-  write32<E>(Buf + 4, Out<ELFT>::EhFrame->Addr - this->getVA() - 4);
+  write32<E>(Buf + 4, In<ELFT>::EhFrame->getParent()->Addr - this->getVA() - 4);
   write32<E>(Buf + 8, Fdes.size());
   Buf += 12;
 
-  uintX_t VA = this->getVA();
+  uint64_t VA = this->getVA();
   for (FdeData &Fde : Fdes) {
     write32<E>(Buf, Fde.Pc - VA);
     write32<E>(Buf + 4, Fde.FdeVA - VA);
@@ -1658,7 +1968,7 @@ template <class ELFT> void EhFrameHeader<ELFT>::writeTo(uint8_t *Buf) {
 
 template <class ELFT> size_t EhFrameHeader<ELFT>::getSize() const {
   // .eh_frame_hdr has a 12 bytes header followed by an array of FDEs.
-  return 12 + Out<ELFT>::EhFrame->NumFdes * 8;
+  return 12 + In<ELFT>::EhFrame->NumFdes * 8;
 }
 
 template <class ELFT>
@@ -1667,13 +1977,13 @@ void EhFrameHeader<ELFT>::addFde(uint32_t Pc, uint32_t FdeVA) {
 }
 
 template <class ELFT> bool EhFrameHeader<ELFT>::empty() const {
-  return Out<ELFT>::EhFrame->empty();
+  return In<ELFT>::EhFrame->empty();
 }
 
 template <class ELFT>
 VersionDefinitionSection<ELFT>::VersionDefinitionSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC, SHT_GNU_verdef, sizeof(uint32_t),
-                             ".gnu.version_d") {}
+    : SyntheticSection(SHF_ALLOC, SHT_GNU_verdef, sizeof(uint32_t),
+                       ".gnu.version_d") {}
 
 static StringRef getFileDefName() {
   if (!Config->SoName.empty())
@@ -1681,17 +1991,17 @@ static StringRef getFileDefName() {
   return Config->OutputFile;
 }
 
-template <class ELFT> void VersionDefinitionSection<ELFT>::finalize() {
-  FileDefNameOff = In<ELFT>::DynStrTab->addString(getFileDefName());
+template <class ELFT> void VersionDefinitionSection<ELFT>::finalizeContents() {
+  FileDefNameOff = InX::DynStrTab->addString(getFileDefName());
   for (VersionDefinition &V : Config->VersionDefinitions)
-    V.NameOff = In<ELFT>::DynStrTab->addString(V.Name);
+    V.NameOff = InX::DynStrTab->addString(V.Name);
 
-  this->OutSec->Link = this->Link = In<ELFT>::DynStrTab->OutSec->SectionIndex;
+  getParent()->Link = InX::DynStrTab->getParent()->SectionIndex;
 
   // sh_info should be set to the number of definitions. This fact is missed in
   // documentation, but confirmed by binutils community:
   // https://sourceware.org/ml/binutils/2014-11/msg00355.html
-  this->OutSec->Info = this->Info = getVerDefNum();
+  getParent()->Info = getVerDefNum();
 }
 
 template <class ELFT>
@@ -1731,23 +2041,24 @@ template <class ELFT> size_t VersionDefinitionSection<ELFT>::getSize() const {
 
 template <class ELFT>
 VersionTableSection<ELFT>::VersionTableSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC, SHT_GNU_versym, sizeof(uint16_t),
-                             ".gnu.version") {}
+    : SyntheticSection(SHF_ALLOC, SHT_GNU_versym, sizeof(uint16_t),
+                       ".gnu.version") {
+  this->Entsize = sizeof(Elf_Versym);
+}
 
-template <class ELFT> void VersionTableSection<ELFT>::finalize() {
-  this->OutSec->Entsize = this->Entsize = sizeof(Elf_Versym);
+template <class ELFT> void VersionTableSection<ELFT>::finalizeContents() {
   // At the moment of june 2016 GNU docs does not mention that sh_link field
   // should be set, but Sun docs do. Also readelf relies on this field.
-  this->OutSec->Link = this->Link = In<ELFT>::DynSymTab->OutSec->SectionIndex;
+  getParent()->Link = InX::DynSymTab->getParent()->SectionIndex;
 }
 
 template <class ELFT> size_t VersionTableSection<ELFT>::getSize() const {
-  return sizeof(Elf_Versym) * (In<ELFT>::DynSymTab->getSymbols().size() + 1);
+  return sizeof(Elf_Versym) * (InX::DynSymTab->getSymbols().size() + 1);
 }
 
 template <class ELFT> void VersionTableSection<ELFT>::writeTo(uint8_t *Buf) {
   auto *OutVersym = reinterpret_cast<Elf_Versym *>(Buf) + 1;
-  for (const SymbolTableEntry &S : In<ELFT>::DynSymTab->getSymbols()) {
+  for (const SymbolTableEntry &S : InX::DynSymTab->getSymbols()) {
     OutVersym->vs_index = S.Symbol->symbol()->VersionId;
     ++OutVersym;
   }
@@ -1759,8 +2070,8 @@ template <class ELFT> bool VersionTableSection<ELFT>::empty() const {
 
 template <class ELFT>
 VersionNeedSection<ELFT>::VersionNeedSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC, SHT_GNU_verneed, sizeof(uint32_t),
-                             ".gnu.version_r") {
+    : SyntheticSection(SHF_ALLOC, SHT_GNU_verneed, sizeof(uint32_t),
+                       ".gnu.version_r") {
   // Identifiers in verneed section start at 2 because 0 and 1 are reserved
   // for VER_NDX_LOCAL and VER_NDX_GLOBAL.
   // First identifiers are reserved by verdef section if it exist.
@@ -1768,24 +2079,27 @@ VersionNeedSection<ELFT>::VersionNeedSection()
 }
 
 template <class ELFT>
-void VersionNeedSection<ELFT>::addSymbol(SharedSymbol<ELFT> *SS) {
-  if (!SS->Verdef) {
+void VersionNeedSection<ELFT>::addSymbol(SharedSymbol *SS) {
+  auto *Ver = reinterpret_cast<const typename ELFT::Verdef *>(SS->Verdef);
+  if (!Ver) {
     SS->symbol()->VersionId = VER_NDX_GLOBAL;
     return;
   }
-  SharedFile<ELFT> *F = SS->file();
+
+  auto *File = cast<SharedFile<ELFT>>(SS->File);
+
   // If we don't already know that we need an Elf_Verneed for this DSO, prepare
   // to create one by adding it to our needed list and creating a dynstr entry
   // for the soname.
-  if (F->VerdefMap.empty())
-    Needed.push_back({F, In<ELFT>::DynStrTab->addString(F->getSoName())});
-  typename SharedFile<ELFT>::NeededVer &NV = F->VerdefMap[SS->Verdef];
+  if (File->VerdefMap.empty())
+    Needed.push_back({File, InX::DynStrTab->addString(File->SoName)});
+  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.
   if (NV.Index == 0) {
-    NV.StrTab = In<ELFT>::DynStrTab->addString(
-        SS->file()->getStringTable().data() + SS->Verdef->getAux()->vda_name);
+    NV.StrTab = InX::DynStrTab->addString(File->getStringTable().data() +
+                                          Ver->getAux()->vda_name);
     NV.Index = NextIndex++;
   }
   SS->symbol()->VersionId = NV.Index;
@@ -1826,9 +2140,9 @@ template <class ELFT> void VersionNeedSection<ELFT>::writeTo(uint8_t *Buf) {
   Verneed[-1].vn_next = 0;
 }
 
-template <class ELFT> void VersionNeedSection<ELFT>::finalize() {
-  this->OutSec->Link = this->Link = In<ELFT>::DynStrTab->OutSec->SectionIndex;
-  this->OutSec->Info = this->Info = Needed.size();
+template <class ELFT> void VersionNeedSection<ELFT>::finalizeContents() {
+  getParent()->Link = InX::DynStrTab->getParent()->SectionIndex;
+  getParent()->Info = Needed.size();
 }
 
 template <class ELFT> size_t VersionNeedSection<ELFT>::getSize() const {
@@ -1842,53 +2156,219 @@ template <class ELFT> bool VersionNeedSection<ELFT>::empty() const {
   return getNeedNum() == 0;
 }
 
-template <class ELFT>
-MipsRldMapSection<ELFT>::MipsRldMapSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS,
-                             sizeof(typename ELFT::uint), ".rld_map") {}
+MergeSyntheticSection::MergeSyntheticSection(StringRef Name, uint32_t Type,
+                                             uint64_t Flags, uint32_t Alignment)
+    : SyntheticSection(Flags, Type, Alignment, Name),
+      Builder(StringTableBuilder::RAW, Alignment) {}
+
+void MergeSyntheticSection::addSection(MergeInputSection *MS) {
+  MS->Parent = this;
+  Sections.push_back(MS);
+}
+
+void MergeSyntheticSection::writeTo(uint8_t *Buf) { Builder.write(Buf); }
+
+bool MergeSyntheticSection::shouldTailMerge() const {
+  return (this->Flags & SHF_STRINGS) && Config->Optimize >= 2;
+}
+
+void MergeSyntheticSection::finalizeTailMerge() {
+  // Add all string pieces to the string table builder to create section
+  // contents.
+  for (MergeInputSection *Sec : Sections)
+    for (size_t I = 0, E = Sec->Pieces.size(); I != E; ++I)
+      if (Sec->Pieces[I].Live)
+        Builder.add(Sec->getData(I));
+
+  // Fix the string table content. After this, the contents will never change.
+  Builder.finalize();
+
+  // finalize() fixed tail-optimized strings, so we can now get
+  // offsets of strings. Get an offset for each string and save it
+  // to a corresponding StringPiece for easy access.
+  for (MergeInputSection *Sec : Sections)
+    for (size_t I = 0, E = Sec->Pieces.size(); I != E; ++I)
+      if (Sec->Pieces[I].Live)
+        Sec->Pieces[I].OutputOff = Builder.getOffset(Sec->getData(I));
+}
+
+void MergeSyntheticSection::finalizeNoTailMerge() {
+  // Add all string pieces to the string table builder to create section
+  // contents. Because we are not tail-optimizing, offsets of strings are
+  // fixed when they are added to the builder (string table builder contains
+  // a hash table from strings to offsets).
+  for (MergeInputSection *Sec : Sections)
+    for (size_t I = 0, E = Sec->Pieces.size(); I != E; ++I)
+      if (Sec->Pieces[I].Live)
+        Sec->Pieces[I].OutputOff = Builder.add(Sec->getData(I));
+
+  Builder.finalizeInOrder();
+}
+
+void MergeSyntheticSection::finalizeContents() {
+  if (shouldTailMerge())
+    finalizeTailMerge();
+  else
+    finalizeNoTailMerge();
+}
+
+size_t MergeSyntheticSection::getSize() const { return Builder.getSize(); }
+
+// This function decompresses compressed sections and scans over the input
+// sections to create mergeable synthetic sections. It removes
+// MergeInputSections from the input section array and adds new synthetic
+// sections at the location of the first input section 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::decompressAndMergeSections() {
+  // splitIntoPieces needs to be called on each MergeInputSection before calling
+  // finalizeContents(). Do that first.
+  parallelForEach(InputSections.begin(), InputSections.end(),
+                  [](InputSectionBase *S) {
+                    if (!S->Live)
+                      return;
+                    if (Decompressor::isCompressedELFSection(S->Flags, S->Name))
+                      S->uncompress();
+                    if (auto *MS = dyn_cast<MergeInputSection>(S))
+                      MS->splitIntoPieces();
+                  });
+
+  std::vector<MergeSyntheticSection *> MergeSections;
+  for (InputSectionBase *&S : InputSections) {
+    MergeInputSection *MS = dyn_cast<MergeInputSection>(S);
+    if (!MS)
+      continue;
+
+    // We do not want to handle sections that are not alive, so just remove
+    // them instead of trying to merge.
+    if (!MS->Live)
+      continue;
+
+    StringRef OutsecName = getOutputSectionName(MS->Name);
+    uint64_t Flags = MS->Flags & ~(uint64_t)SHF_GROUP;
+    uint32_t Alignment = std::max<uint32_t>(MS->Alignment, MS->Entsize);
+
+    auto I = llvm::find_if(MergeSections, [=](MergeSyntheticSection *Sec) {
+      return Sec->Name == OutsecName && Sec->Flags == Flags &&
+             Sec->Alignment == Alignment;
+    });
+    if (I == MergeSections.end()) {
+      MergeSyntheticSection *Syn =
+          make<MergeSyntheticSection>(OutsecName, MS->Type, Flags, Alignment);
+      MergeSections.push_back(Syn);
+      I = std::prev(MergeSections.end());
+      S = Syn;
+    } else {
+      S = nullptr;
+    }
+    (*I)->addSection(MS);
+  }
+  for (auto *MS : MergeSections)
+    MS->finalizeContents();
 
-template <class ELFT> void MipsRldMapSection<ELFT>::writeTo(uint8_t *Buf) {
-  // Apply filler from linker script.
-  uint64_t Filler = Script<ELFT>::X->getFiller(this->Name);
-  Filler = (Filler << 32) | Filler;
-  memcpy(Buf, &Filler, getSize());
+  std::vector<InputSectionBase *> &V = InputSections;
+  V.erase(std::remove(V.begin(), V.end(), nullptr), V.end());
 }
 
-template <class ELFT>
-ARMExidxSentinelSection<ELFT>::ARMExidxSentinelSection()
-    : SyntheticSection<ELFT>(SHF_ALLOC | SHF_LINK_ORDER, SHT_ARM_EXIDX,
-                             sizeof(typename ELFT::uint), ".ARM.exidx") {}
+MipsRldMapSection::MipsRldMapSection()
+    : SyntheticSection(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS, Config->Wordsize,
+                       ".rld_map") {}
+
+ARMExidxSentinelSection::ARMExidxSentinelSection()
+    : SyntheticSection(SHF_ALLOC | SHF_LINK_ORDER, SHT_ARM_EXIDX,
+                       Config->Wordsize, ".ARM.exidx") {}
 
 // Write a terminating sentinel entry to the end of the .ARM.exidx table.
 // This section will have been sorted last in the .ARM.exidx table.
 // This table entry will have the form:
 // | PREL31 upper bound of code that has exception tables | EXIDX_CANTUNWIND |
-template <class ELFT>
-void ARMExidxSentinelSection<ELFT>::writeTo(uint8_t *Buf) {
-  // Get the InputSection before us, we are by definition last
-  auto RI = cast<OutputSection<ELFT>>(this->OutSec)->Sections.rbegin();
-  InputSection<ELFT> *LE = *(++RI);
-  InputSection<ELFT> *LC = cast<InputSection<ELFT>>(LE->getLinkOrderDep());
-  uint64_t S = LC->OutSec->Addr + LC->getOffset(LC->getSize());
-  uint64_t P = this->getVA();
+// The sentinel must have the PREL31 value of an address higher than any
+// address described by any other table entry.
+void ARMExidxSentinelSection::writeTo(uint8_t *Buf) {
+  // The Sections are sorted in order of ascending PREL31 address with the
+  // sentinel last. We need to find the InputSection that precedes the
+  // sentinel. By construction the Sentinel is in the last
+  // InputSectionDescription as the InputSection that precedes it.
+  OutputSectionCommand *C = Script->getCmd(getParent());
+  auto ISD = std::find_if(C->Commands.rbegin(), C->Commands.rend(),
+                          [](const BaseCommand *Base) {
+                            return isa<InputSectionDescription>(Base);
+                          });
+  auto L = cast<InputSectionDescription>(*ISD);
+  InputSection *Highest = L->Sections[L->Sections.size() - 2];
+  InputSection *LS = Highest->getLinkOrderDep();
+  uint64_t S = LS->getParent()->Addr + LS->getOffset(LS->getSize());
+  uint64_t P = getVA();
   Target->relocateOne(Buf, R_ARM_PREL31, S - P);
   write32le(Buf + 4, 0x1);
 }
 
-template InputSection<ELF32LE> *elf::createCommonSection();
-template InputSection<ELF32BE> *elf::createCommonSection();
-template InputSection<ELF64LE> *elf::createCommonSection();
-template InputSection<ELF64BE> *elf::createCommonSection();
-
-template InputSection<ELF32LE> *elf::createInterpSection();
-template InputSection<ELF32BE> *elf::createInterpSection();
-template InputSection<ELF64LE> *elf::createInterpSection();
-template InputSection<ELF64BE> *elf::createInterpSection();
-
-template MergeInputSection<ELF32LE> *elf::createCommentSection();
-template MergeInputSection<ELF32BE> *elf::createCommentSection();
-template MergeInputSection<ELF64LE> *elf::createCommentSection();
-template MergeInputSection<ELF64BE> *elf::createCommentSection();
+ThunkSection::ThunkSection(OutputSection *OS, uint64_t Off)
+    : SyntheticSection(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS,
+                       Config->Wordsize, ".text.thunk") {
+  this->Parent = OS;
+  this->OutSecOff = 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);
+}
+
+InputSection *ThunkSection::getTargetInputSection() const {
+  const Thunk *T = Thunks.front();
+  return T->getTargetInputSection();
+}
+
+InputSection *InX::ARMAttributes;
+BssSection *InX::Bss;
+BssSection *InX::BssRelRo;
+BuildIdSection *InX::BuildId;
+InputSection *InX::Common;
+SyntheticSection *InX::Dynamic;
+StringTableSection *InX::DynStrTab;
+SymbolTableBaseSection *InX::DynSymTab;
+InputSection *InX::Interp;
+GdbIndexSection *InX::GdbIndex;
+GotSection *InX::Got;
+GotPltSection *InX::GotPlt;
+GnuHashTableSection *InX::GnuHashTab;
+IgotPltSection *InX::IgotPlt;
+MipsGotSection *InX::MipsGot;
+MipsRldMapSection *InX::MipsRldMap;
+PltSection *InX::Plt;
+PltSection *InX::Iplt;
+StringTableSection *InX::ShStrTab;
+StringTableSection *InX::StrTab;
+SymbolTableBaseSection *InX::SymTab;
+
+template GdbIndexSection *elf::createGdbIndex<ELF32LE>();
+template GdbIndexSection *elf::createGdbIndex<ELF32BE>();
+template GdbIndexSection *elf::createGdbIndex<ELF64LE>();
+template GdbIndexSection *elf::createGdbIndex<ELF64BE>();
+
+template void PltSection::addEntry<ELF32LE>(SymbolBody &Sym);
+template void PltSection::addEntry<ELF32BE>(SymbolBody &Sym);
+template void PltSection::addEntry<ELF64LE>(SymbolBody &Sym);
+template void PltSection::addEntry<ELF64BE>(SymbolBody &Sym);
+
+template InputSection *elf::createCommonSection<ELF32LE>();
+template InputSection *elf::createCommonSection<ELF32BE>();
+template InputSection *elf::createCommonSection<ELF64LE>();
+template InputSection *elf::createCommonSection<ELF64BE>();
+
+template MergeInputSection *elf::createCommentSection<ELF32LE>();
+template MergeInputSection *elf::createCommentSection<ELF32BE>();
+template MergeInputSection *elf::createCommentSection<ELF64LE>();
+template MergeInputSection *elf::createCommentSection<ELF64BE>();
 
 template class elf::MipsAbiFlagsSection<ELF32LE>;
 template class elf::MipsAbiFlagsSection<ELF32BE>;
@@ -1905,36 +2385,6 @@ template class elf::MipsReginfoSection<ELF32BE>;
 template class elf::MipsReginfoSection<ELF64LE>;
 template class elf::MipsReginfoSection<ELF64BE>;
 
-template class elf::BuildIdSection<ELF32LE>;
-template class elf::BuildIdSection<ELF32BE>;
-template class elf::BuildIdSection<ELF64LE>;
-template class elf::BuildIdSection<ELF64BE>;
-
-template class elf::GotSection<ELF32LE>;
-template class elf::GotSection<ELF32BE>;
-template class elf::GotSection<ELF64LE>;
-template class elf::GotSection<ELF64BE>;
-
-template class elf::MipsGotSection<ELF32LE>;
-template class elf::MipsGotSection<ELF32BE>;
-template class elf::MipsGotSection<ELF64LE>;
-template class elf::MipsGotSection<ELF64BE>;
-
-template class elf::GotPltSection<ELF32LE>;
-template class elf::GotPltSection<ELF32BE>;
-template class elf::GotPltSection<ELF64LE>;
-template class elf::GotPltSection<ELF64BE>;
-
-template class elf::IgotPltSection<ELF32LE>;
-template class elf::IgotPltSection<ELF32BE>;
-template class elf::IgotPltSection<ELF64LE>;
-template class elf::IgotPltSection<ELF64BE>;
-
-template class elf::StringTableSection<ELF32LE>;
-template class elf::StringTableSection<ELF32BE>;
-template class elf::StringTableSection<ELF64LE>;
-template class elf::StringTableSection<ELF64BE>;
-
 template class elf::DynamicSection<ELF32LE>;
 template class elf::DynamicSection<ELF32BE>;
 template class elf::DynamicSection<ELF64LE>;
@@ -1950,31 +2400,11 @@ template class elf::SymbolTableSection<ELF32BE>;
 template class elf::SymbolTableSection<ELF64LE>;
 template class elf::SymbolTableSection<ELF64BE>;
 
-template class elf::GnuHashTableSection<ELF32LE>;
-template class elf::GnuHashTableSection<ELF32BE>;
-template class elf::GnuHashTableSection<ELF64LE>;
-template class elf::GnuHashTableSection<ELF64BE>;
-
 template class elf::HashTableSection<ELF32LE>;
 template class elf::HashTableSection<ELF32BE>;
 template class elf::HashTableSection<ELF64LE>;
 template class elf::HashTableSection<ELF64BE>;
 
-template class elf::PltSection<ELF32LE>;
-template class elf::PltSection<ELF32BE>;
-template class elf::PltSection<ELF64LE>;
-template class elf::PltSection<ELF64BE>;
-
-template class elf::IpltSection<ELF32LE>;
-template class elf::IpltSection<ELF32BE>;
-template class elf::IpltSection<ELF64LE>;
-template class elf::IpltSection<ELF64BE>;
-
-template class elf::GdbIndexSection<ELF32LE>;
-template class elf::GdbIndexSection<ELF32BE>;
-template class elf::GdbIndexSection<ELF64LE>;
-template class elf::GdbIndexSection<ELF64BE>;
-
 template class elf::EhFrameHeader<ELF32LE>;
 template class elf::EhFrameHeader<ELF32BE>;
 template class elf::EhFrameHeader<ELF64LE>;
@@ -1995,12 +2425,7 @@ template class elf::VersionDefinitionSection<ELF32BE>;
 template class elf::VersionDefinitionSection<ELF64LE>;
 template class elf::VersionDefinitionSection<ELF64BE>;
 
-template class elf::MipsRldMapSection<ELF32LE>;
-template class elf::MipsRldMapSection<ELF32BE>;
-template class elf::MipsRldMapSection<ELF64LE>;
-template class elf::MipsRldMapSection<ELF64BE>;
-
-template class elf::ARMExidxSentinelSection<ELF32LE>;
-template class elf::ARMExidxSentinelSection<ELF32BE>;
-template class elf::ARMExidxSentinelSection<ELF64LE>;
-template class elf::ARMExidxSentinelSection<ELF64BE>;
+template class elf::EhFrameSection<ELF32LE>;
+template class elf::EhFrameSection<ELF32BE>;
+template class elf::EhFrameSection<ELF64LE>;
+template class elf::EhFrameSection<ELF64BE>;
diff --git a/gnu/llvm/tools/lld/tools/lld/lld.cpp b/gnu/llvm/tools/lld/tools/lld/lld.cpp
index 037f43c8cb6..4a68ed7cab9 100644
--- a/gnu/llvm/tools/lld/tools/lld/lld.cpp
+++ b/gnu/llvm/tools/lld/tools/lld/lld.cpp
@@ -43,9 +43,9 @@ LLVM_ATTRIBUTE_NORETURN static void die(const Twine &S) {
 
 static Flavor getFlavor(StringRef S) {
   return StringSwitch<Flavor>(S)
-      .Cases("ld", "ld.lld", "gnu", Gnu)
-      .Case("link", WinLink)
-      .Case("darwin", Darwin)
+      .CasesLower("ld", "ld.lld", "gnu", Gnu)
+      .CaseLower("link", WinLink)
+      .CaseLower("darwin", Darwin)
       .Default(Invalid);
 }
 
@@ -110,6 +110,6 @@ int main(int Argc, const char **Argv) {
 #endif
   default:
     die("lld is a generic driver.\n"
-        "Invoke ld.lld (Unix), ld (Mac) or lld-link (Windows) instead.");
+        "Invoke ld.lld (Unix), ld (macOS) or lld-link (Windows) instead.");
   }
 }