Merge to Cygnus 961112 + add some support (not ready) for shared libs

1 files changed, 814 insertions, 0 deletions

diff --git a/gnu/usr.bin/binutils/gdb/elfread.c b/gnu/usr.bin/binutils/gdb/elfread.c
new file mode 100644
index 00000000000..107bdafa37e
--- /dev/null
+++ b/gnu/usr.bin/binutils/gdb/elfread.c
@@ -0,0 +1,814 @@
+/* Read ELF (Executable and Linking Format) object files for GDB.
+   Copyright 1991, 1992, 1993, 1994, 1995, 1996 Free Software Foundation, Inc.
+   Written by Fred Fish at Cygnus Support.
+
+This file is part of GDB.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "bfd.h"
+#include "gdb_string.h"
+#include "elf-bfd.h"
+#include "elf/mips.h"
+#include "symtab.h"
+#include "symfile.h"
+#include "objfiles.h"
+#include "buildsym.h"
+#include "stabsread.h"
+#include "gdb-stabs.h"
+#include "complaints.h"
+#include "demangle.h"
+
+/* The struct elfinfo is available only during ELF symbol table and
+   psymtab reading.  It is destroyed at the complation of psymtab-reading.
+   It's local to elf_symfile_read.  */
+
+struct elfinfo {
+  file_ptr dboffset;		/* Offset to dwarf debug section */
+  unsigned int dbsize;		/* Size of dwarf debug section */
+  file_ptr lnoffset;		/* Offset to dwarf line number section */
+  unsigned int lnsize;		/* Size of dwarf line number section */
+  asection *stabsect;		/* Section pointer for .stab section */
+  asection *stabindexsect;	/* Section pointer for .stab.index section */
+  asection *mdebugsect;		/* Section pointer for .mdebug section */
+};
+
+/* Various things we might complain about... */
+
+struct complaint section_info_complaint = 
+  {"elf/stab section information %s without a preceding file symbol", 0, 0};
+
+struct complaint section_info_dup_complaint = 
+  {"duplicated elf/stab section information for %s", 0, 0};
+
+struct complaint stab_info_mismatch_complaint = 
+  {"elf/stab section information missing for %s", 0, 0};
+
+struct complaint stab_info_questionable_complaint = 
+  {"elf/stab section information questionable for %s", 0, 0};
+
+static void
+elf_symfile_init PARAMS ((struct objfile *));
+
+static void
+elf_new_init PARAMS ((struct objfile *));
+
+static void
+elf_symfile_read PARAMS ((struct objfile *, struct section_offsets *, int));
+
+static void
+elf_symfile_finish PARAMS ((struct objfile *));
+
+static void
+elf_symtab_read PARAMS ((bfd *,  CORE_ADDR, struct objfile *, int));
+
+static void
+free_elfinfo PARAMS ((void *));
+
+static struct minimal_symbol *
+record_minimal_symbol_and_info PARAMS ((char *, CORE_ADDR,
+					enum minimal_symbol_type, char *,
+					struct objfile *));
+
+static void
+elf_locate_sections PARAMS ((bfd *, asection *, void *));
+
+/* We are called once per section from elf_symfile_read.  We
+   need to examine each section we are passed, check to see
+   if it is something we are interested in processing, and
+   if so, stash away some access information for the section.
+
+   For now we recognize the dwarf debug information sections and
+   line number sections from matching their section names.  The
+   ELF definition is no real help here since it has no direct
+   knowledge of DWARF (by design, so any debugging format can be
+   used).
+
+   We also recognize the ".stab" sections used by the Sun compilers
+   released with Solaris 2.
+
+   FIXME: The section names should not be hardwired strings (what
+   should they be?  I don't think most object file formats have enough
+   section flags to specify what kind of debug section it is
+   -kingdon).  */
+
+static void
+elf_locate_sections (ignore_abfd, sectp, eip)
+     bfd *ignore_abfd;
+     asection *sectp;
+     PTR eip;
+{
+  register struct elfinfo *ei;
+
+  ei = (struct elfinfo *) eip;
+  if (STREQ (sectp -> name, ".debug"))
+    {
+      ei -> dboffset = sectp -> filepos;
+      ei -> dbsize = bfd_get_section_size_before_reloc (sectp);
+    }
+  else if (STREQ (sectp -> name, ".line"))
+    {
+      ei -> lnoffset = sectp -> filepos;
+      ei -> lnsize = bfd_get_section_size_before_reloc (sectp);
+    }
+  else if (STREQ (sectp -> name, ".stab"))
+    {
+      ei -> stabsect = sectp;
+    }
+  else if (STREQ (sectp -> name, ".stab.index"))
+    {
+      ei -> stabindexsect = sectp;
+    }
+  else if (STREQ (sectp -> name, ".mdebug"))
+    {
+      ei -> mdebugsect = sectp;
+    }
+}
+
+#if 0	/* Currently unused */
+
+char *
+elf_interpreter (abfd)
+     bfd *abfd;
+{
+  sec_ptr interp_sec;
+  unsigned size;
+  char *interp = NULL;
+
+  interp_sec = bfd_get_section_by_name (abfd, ".interp");
+  if (interp_sec)
+    {
+      size = bfd_section_size (abfd, interp_sec);
+      interp = alloca (size);
+      if (bfd_get_section_contents (abfd, interp_sec, interp, (file_ptr)0,
+				    size))
+	{
+	  interp = savestring (interp, size - 1);
+	}
+      else
+	{
+	  interp = NULL;
+	}
+    }
+  return (interp);
+}
+
+#endif
+
+static struct minimal_symbol *
+record_minimal_symbol_and_info (name, address, ms_type, info, objfile)
+     char *name;
+     CORE_ADDR address;
+     enum minimal_symbol_type ms_type;
+     char *info;		/* FIXME, is this really char *? */
+     struct objfile *objfile;
+{
+  int section;
+
+  /* Guess the section from the type.  This is likely to be wrong in
+     some cases.  */
+  switch (ms_type)
+    {
+    case mst_text:
+    case mst_file_text:
+      section = SECT_OFF_TEXT;
+#ifdef SMASH_TEXT_ADDRESS
+      SMASH_TEXT_ADDRESS (address);
+#endif
+      break;
+    case mst_data:
+    case mst_file_data:
+      section = SECT_OFF_DATA;
+      break;
+    case mst_bss:
+    case mst_file_bss:
+      section = SECT_OFF_BSS;
+      break;
+    default:
+      section = -1;
+      break;
+    }
+
+  return prim_record_minimal_symbol_and_info
+    (name, address, ms_type, info, section, objfile);
+}
+
+/*
+
+LOCAL FUNCTION
+
+	elf_symtab_read -- read the symbol table of an ELF file
+
+SYNOPSIS
+
+	void elf_symtab_read (bfd *abfd, CORE_ADDR addr,
+			      struct objfile *objfile, int dynamic)
+
+DESCRIPTION
+
+	Given an open bfd, a base address to relocate symbols to, and a
+	flag that specifies whether or not this bfd is for an executable
+	or not (may be shared library for example), add all the global
+	function and data symbols to the minimal symbol table.
+
+	In stabs-in-ELF, as implemented by Sun, there are some local symbols
+	defined in the ELF symbol table, which can be used to locate
+	the beginnings of sections from each ".o" file that was linked to
+	form the executable objfile.  We gather any such info and record it
+	in data structures hung off the objfile's private data.
+
+*/
+
+static void
+elf_symtab_read (abfd, addr, objfile, dynamic)
+     bfd *abfd;
+     CORE_ADDR addr;
+     struct objfile *objfile;
+     int dynamic;
+{
+  long storage_needed;
+  asymbol *sym;
+  asymbol **symbol_table;
+  long number_of_symbols;
+  long i;
+  int index;
+  struct cleanup *back_to;
+  CORE_ADDR symaddr;
+  enum minimal_symbol_type ms_type;
+  /* If sectinfo is nonNULL, it contains section info that should end up
+     filed in the objfile.  */
+  struct stab_section_info *sectinfo = NULL;
+  /* If filesym is nonzero, it points to a file symbol, but we haven't
+     seen any section info for it yet.  */
+  asymbol *filesym = 0;
+#ifdef SOFUN_ADDRESS_MAYBE_MISSING
+  /* Name of filesym, as saved on the symbol_obstack.  */
+  char *filesymname = obsavestring ("", 0, &objfile->symbol_obstack);
+#endif
+  struct dbx_symfile_info *dbx = (struct dbx_symfile_info *)
+				 objfile->sym_stab_info;
+  unsigned long size;
+  int stripped = (bfd_get_symcount (abfd) == 0);
+ 
+  if (dynamic)
+    {
+      storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd);
+
+      /* Nothing to be done if there is no dynamic symtab.  */
+      if (storage_needed < 0)
+	return;
+    }
+  else
+    {
+      storage_needed = bfd_get_symtab_upper_bound (abfd);
+      if (storage_needed < 0)
+	error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
+	       bfd_errmsg (bfd_get_error ()));
+    }
+  if (storage_needed > 0)
+    {
+      symbol_table = (asymbol **) xmalloc (storage_needed);
+      back_to = make_cleanup (free, symbol_table);
+      if (dynamic)
+        number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd,
+							     symbol_table);
+      else
+        number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
+      if (number_of_symbols < 0)
+	error ("Can't read symbols from %s: %s", bfd_get_filename (abfd),
+	       bfd_errmsg (bfd_get_error ()));
+      for (i = 0; i < number_of_symbols; i++)
+	{
+	  sym = symbol_table[i];
+	  if (sym -> name == NULL || *sym -> name == '\0')
+	    {
+	      /* Skip names that don't exist (shouldn't happen), or names
+		 that are null strings (may happen). */
+	      continue;
+	    }
+
+	  if (dynamic
+	      && sym -> section == &bfd_und_section
+	      && (sym -> flags & BSF_FUNCTION))
+	    {
+	      struct minimal_symbol *msym;
+
+	      /* Symbol is a reference to a function defined in
+		 a shared library.
+		 If its value is non zero then it is usually the address
+		 of the corresponding entry in the procedure linkage table,
+		 relative to the base address.
+		 If its value is zero then the dynamic linker has to resolve
+		 the symbol. We are unable to find any meaningful address
+		 for this symbol in the executable file, so we skip it.  */
+	      symaddr = sym -> value;
+	      if (symaddr == 0)
+		continue;
+	      symaddr += addr;
+	      msym = record_minimal_symbol_and_info
+		((char *) sym -> name, symaddr,
+		mst_solib_trampoline, NULL, objfile);
+#ifdef SOFUN_ADDRESS_MAYBE_MISSING
+	      if (msym != NULL)
+		msym->filename = filesymname;
+#endif
+	      continue;
+	    }
+
+	  /* If it is a nonstripped executable, do not enter dynamic
+	     symbols, as the dynamic symbol table is usually a subset
+	     of the main symbol table.  */
+	  if (dynamic && !stripped)
+	    continue;
+	  if (sym -> flags & BSF_FILE)
+	    {
+	      /* STT_FILE debugging symbol that helps stabs-in-elf debugging.
+		 Chain any old one onto the objfile; remember new sym.  */
+	      if (sectinfo != NULL)
+		{
+		  sectinfo -> next = dbx -> stab_section_info;
+		  dbx -> stab_section_info = sectinfo;
+		  sectinfo = NULL;
+		}
+	      filesym = sym;
+#ifdef SOFUN_ADDRESS_MAYBE_MISSING
+	      filesymname =
+		obsavestring ((char *)filesym->name, strlen (filesym->name),
+			      &objfile->symbol_obstack);
+#endif
+	    }
+	  else if (sym -> flags & (BSF_GLOBAL | BSF_LOCAL | BSF_WEAK))
+	    {
+	      struct minimal_symbol *msym;
+
+	      /* Select global/local/weak symbols.  Note that bfd puts abs
+		 symbols in their own section, so all symbols we are
+		 interested in will have a section. */
+	      /* Bfd symbols are section relative. */
+	      symaddr = sym -> value + sym -> section -> vma;
+	      /* Relocate all non-absolute symbols by base address.  */
+	      if (sym -> section != &bfd_abs_section)
+		{
+		  symaddr += addr;
+		}
+	      /* For non-absolute symbols, use the type of the section
+		 they are relative to, to intuit text/data.  Bfd provides
+		 no way of figuring this out for absolute symbols. */
+	      if (sym -> section == &bfd_abs_section)
+		{
+		  /* This is a hack to get the minimal symbol type
+		     right for Irix 5, which has absolute adresses
+		     with special section indices for dynamic symbols. */
+		  unsigned short shndx =
+		    ((elf_symbol_type *) sym)->internal_elf_sym.st_shndx;
+
+		  switch (shndx)
+		    {
+		    case SHN_MIPS_TEXT:
+		      ms_type = mst_text;
+		      break;
+		    case SHN_MIPS_DATA:
+		      ms_type = mst_data;
+		      break;
+		    case SHN_MIPS_ACOMMON:
+		      ms_type = mst_bss;
+		      break;
+		    default:
+		      ms_type = mst_abs;
+		    }
+		}
+	      else if (sym -> section -> flags & SEC_CODE)
+		{
+		  if (sym -> flags & BSF_GLOBAL)
+		    {
+		      ms_type = mst_text;
+		    }
+		  else if ((sym->name[0] == '.' && sym->name[1] == 'L')
+			   || ((sym -> flags & BSF_LOCAL)
+			       && sym->name[0] == '$'
+			       && sym->name[1] == 'L'))
+		    /* Looks like a compiler-generated label.  Skip it.
+		       The assembler should be skipping these (to keep
+		       executables small), but apparently with gcc on the
+		       delta m88k SVR4, it loses.  So to have us check too
+		       should be harmless (but I encourage people to fix this
+		       in the assembler instead of adding checks here).  */
+		    continue;
+#ifdef HARRIS_TARGET
+		  else if (sym->name[0] == '.' && sym->name[1] == '.')
+		    {
+		      /* Looks like a Harris compiler generated label for the
+			 purpose of marking instructions that are relevant to
+			 DWARF dies.  The assembler can't get rid of these 
+			 because they are relocatable addresses that the
+			 linker needs to resolve. */
+		      continue;
+		    }
+#endif	  
+		  else
+		    {
+		      ms_type = mst_file_text;
+		    }
+		}
+	      else if (sym -> section -> flags & SEC_ALLOC)
+		{
+		  if (sym -> flags & BSF_GLOBAL)
+		    {
+		      if (sym -> section -> flags & SEC_LOAD)
+			{
+			  ms_type = mst_data;
+			}
+		      else
+			{
+			  ms_type = mst_bss;
+			}
+		    }
+		  else if (sym -> flags & BSF_LOCAL)
+		    {
+		      /* Named Local variable in a Data section.  Check its
+			 name for stabs-in-elf.  The STREQ macro checks the
+			 first character inline, so we only actually do a
+			 strcmp function call on names that start with 'B'
+			 or 'D' */
+		      index = SECT_OFF_MAX;
+		      if (STREQ ("Bbss.bss", sym -> name))
+			{
+			  index = SECT_OFF_BSS;
+			}
+		      else if (STREQ ("Ddata.data", sym -> name))
+			{
+			  index = SECT_OFF_DATA;
+			}
+		      else if (STREQ ("Drodata.rodata", sym -> name))
+			{
+			  index = SECT_OFF_RODATA;
+			}
+		      if (index != SECT_OFF_MAX)
+			{
+			  /* Found a special local symbol.  Allocate a
+			     sectinfo, if needed, and fill it in.  */
+			  if (sectinfo == NULL)
+			    {
+			      sectinfo = (struct stab_section_info *)
+				xmmalloc (objfile -> md, sizeof (*sectinfo));
+			      memset ((PTR) sectinfo, 0, sizeof (*sectinfo));
+			      if (filesym == NULL)
+				{
+				  complain (&section_info_complaint,
+					    sym -> name);
+				}
+			      else
+				{
+				  sectinfo -> filename =
+				    (char *) filesym -> name;
+				}
+			    }
+			  if (sectinfo -> sections[index] != 0)
+			    {
+			      complain (&section_info_dup_complaint,
+					sectinfo -> filename);
+			    }
+			  /* Bfd symbols are section relative. */
+			  symaddr = sym -> value + sym -> section -> vma;
+			  /* Relocate non-absolute symbols by base address.  */
+			  if (sym -> section != &bfd_abs_section)
+			    {
+			      symaddr += addr;
+			    }
+			  sectinfo -> sections[index] = symaddr;
+			  /* The special local symbols don't go in the
+			     minimal symbol table, so ignore this one. */
+			  continue;
+			}
+		      /* Not a special stabs-in-elf symbol, do regular
+			 symbol processing. */
+		      if (sym -> section -> flags & SEC_LOAD)
+			{
+			  ms_type = mst_file_data;
+			}
+		      else
+			{
+			  ms_type = mst_file_bss;
+			}
+		    }
+		  else
+		    {
+		      ms_type = mst_unknown;
+		    }
+		}
+	      else
+		{
+		  /* FIXME:  Solaris2 shared libraries include lots of
+		     odd "absolute" and "undefined" symbols, that play 
+		     hob with actions like finding what function the PC
+		     is in.  Ignore them if they aren't text, data, or bss.  */
+		  /* ms_type = mst_unknown; */
+		  continue;		/* Skip this symbol. */
+		}
+	      /* Pass symbol size field in via BFD.  FIXME!!!  */
+	      size = ((elf_symbol_type *) sym) -> internal_elf_sym.st_size;
+	      msym = record_minimal_symbol_and_info
+		((char *) sym -> name, symaddr,
+		 ms_type, (PTR) size, objfile);
+#ifdef SOFUN_ADDRESS_MAYBE_MISSING
+	      if (msym != NULL)
+		msym->filename = filesymname;
+#endif
+	    }
+	}
+      do_cleanups (back_to);
+    }
+}
+
+/* Scan and build partial symbols for a symbol file.
+   We have been initialized by a call to elf_symfile_init, which 
+   currently does nothing.
+
+   SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
+   in each section.  We simplify it down to a single offset for all
+   symbols.  FIXME.
+
+   MAINLINE is true if we are reading the main symbol
+   table (as opposed to a shared lib or dynamically loaded file).
+
+   This function only does the minimum work necessary for letting the
+   user "name" things symbolically; it does not read the entire symtab.
+   Instead, it reads the external and static symbols and puts them in partial
+   symbol tables.  When more extensive information is requested of a
+   file, the corresponding partial symbol table is mutated into a full
+   fledged symbol table by going back and reading the symbols
+   for real.
+
+   We look for sections with specific names, to tell us what debug
+   format to look for:  FIXME!!!
+
+   dwarf_build_psymtabs() builds psymtabs for DWARF symbols;
+   elfstab_build_psymtabs() handles STABS symbols;
+   mdebug_build_psymtabs() handles ECOFF debugging information.
+
+   Note that ELF files have a "minimal" symbol table, which looks a lot
+   like a COFF symbol table, but has only the minimal information necessary
+   for linking.  We process this also, and use the information to
+   build gdb's minimal symbol table.  This gives us some minimal debugging
+   capability even for files compiled without -g.  */
+
+static void
+elf_symfile_read (objfile, section_offsets, mainline)
+     struct objfile *objfile;
+     struct section_offsets *section_offsets;
+     int mainline;
+{
+  bfd *abfd = objfile->obfd;
+  struct elfinfo ei;
+  struct cleanup *back_to;
+  CORE_ADDR offset;
+
+  init_minimal_symbol_collection ();
+  back_to = make_cleanup (discard_minimal_symbols, 0);
+
+  memset ((char *) &ei, 0, sizeof (ei));
+
+  /* Allocate struct to keep track of the symfile */
+  objfile->sym_stab_info = (PTR)
+    xmmalloc (objfile -> md, sizeof (struct dbx_symfile_info));
+  memset ((char *) objfile->sym_stab_info, 0, sizeof (struct dbx_symfile_info));
+  make_cleanup (free_elfinfo, (PTR) objfile);
+
+  /* Process the normal ELF symbol table first.  This may write some 
+     chain of info into the dbx_symfile_info in objfile->sym_stab_info,
+     which can later be used by elfstab_offset_sections.  */
+
+  /* FIXME, should take a section_offsets param, not just an offset.  */
+  offset = ANOFFSET (section_offsets, 0);
+  elf_symtab_read (abfd, offset, objfile, 0);
+
+  /* Add the dynamic symbols.  */
+
+  elf_symtab_read (abfd, offset, objfile, 1);
+
+  /* Now process debugging information, which is contained in
+     special ELF sections.  We first have to find them... */
+
+  bfd_map_over_sections (abfd, elf_locate_sections, (PTR) &ei);
+  if (dwarf2_has_info (abfd) && !offset)
+    {
+      /* DWARF 2 sections */
+      dwarf2_build_psymtabs (objfile, section_offsets, mainline);
+    }
+  else if (ei.dboffset && ei.lnoffset)
+    {
+      /* DWARF sections */
+      dwarf_build_psymtabs (objfile,
+			    section_offsets, mainline,
+			    ei.dboffset, ei.dbsize,
+			    ei.lnoffset, ei.lnsize);
+    }
+  if (ei.stabsect)
+    {
+      asection *str_sect;
+
+      /* Stab sections have an associated string table that looks like
+	 a separate section.  */
+      str_sect = bfd_get_section_by_name (abfd, ".stabstr");
+
+      /* FIXME should probably warn about a stab section without a stabstr.  */
+      if (str_sect)
+	elfstab_build_psymtabs (objfile,
+				section_offsets,
+				mainline,
+				ei.stabsect->filepos,
+				bfd_section_size (abfd, ei.stabsect),
+				str_sect->filepos,
+				bfd_section_size (abfd, str_sect));
+    }
+  if (ei.mdebugsect)
+    {
+      const struct ecoff_debug_swap *swap;
+
+      /* .mdebug section, presumably holding ECOFF debugging
+	 information.  */
+      swap = get_elf_backend_data (abfd)->elf_backend_ecoff_debug_swap;
+      if (swap)
+	elfmdebug_build_psymtabs (objfile, swap, ei.mdebugsect,
+				  section_offsets);
+    }
+
+  /* Install any minimal symbols that have been collected as the current
+     minimal symbols for this objfile. */
+
+  install_minimal_symbols (objfile);
+
+  do_cleanups (back_to);
+}
+
+/* This cleans up the objfile's sym_stab_info pointer, and the chain of
+   stab_section_info's, that might be dangling from it.  */
+
+static void
+free_elfinfo (objp)
+     PTR objp;
+{
+  struct objfile *objfile = (struct objfile *)objp;
+  struct dbx_symfile_info *dbxinfo = (struct dbx_symfile_info *)
+				     objfile->sym_stab_info;
+  struct stab_section_info *ssi, *nssi;
+
+  ssi = dbxinfo->stab_section_info;
+  while (ssi)
+    {
+      nssi = ssi->next;
+      mfree (objfile->md, ssi);
+      ssi = nssi;
+    }
+
+  dbxinfo->stab_section_info = 0;	/* Just say No mo info about this.  */
+}
+
+
+/* Initialize anything that needs initializing when a completely new symbol
+   file is specified (not just adding some symbols from another file, e.g. a
+   shared library).
+
+   We reinitialize buildsym, since we may be reading stabs from an ELF file.  */
+
+static void
+elf_new_init (ignore)
+     struct objfile *ignore;
+{
+  stabsread_new_init ();
+  buildsym_new_init ();
+}
+
+/* Perform any local cleanups required when we are done with a particular
+   objfile.  I.E, we are in the process of discarding all symbol information
+   for an objfile, freeing up all memory held for it, and unlinking the
+   objfile struct from the global list of known objfiles. */
+
+static void
+elf_symfile_finish (objfile)
+     struct objfile *objfile;
+{
+  if (objfile -> sym_stab_info != NULL)
+    {
+      mfree (objfile -> md, objfile -> sym_stab_info);
+    }
+}
+
+/* ELF specific initialization routine for reading symbols.
+
+   It is passed a pointer to a struct sym_fns which contains, among other
+   things, the BFD for the file whose symbols are being read, and a slot for
+   a pointer to "private data" which we can fill with goodies.
+
+   For now at least, we have nothing in particular to do, so this function is
+   just a stub. */
+
+static void
+elf_symfile_init (objfile)
+     struct objfile *objfile;
+{
+  /* ELF objects may be reordered, so set OBJF_REORDERED.  If we
+     find this causes a significant slowdown in gdb then we could
+     set it in the debug symbol readers only when necessary.  */
+  objfile->flags |= OBJF_REORDERED;
+}
+
+/* When handling an ELF file that contains Sun STABS debug info,
+   some of the debug info is relative to the particular chunk of the
+   section that was generated in its individual .o file.  E.g.
+   offsets to static variables are relative to the start of the data
+   segment *for that module before linking*.  This information is
+   painfully squirreled away in the ELF symbol table as local symbols
+   with wierd names.  Go get 'em when needed.  */
+
+void
+elfstab_offset_sections (objfile, pst)
+     struct objfile *objfile;
+     struct partial_symtab *pst;
+{
+  char *filename = pst->filename;
+  struct dbx_symfile_info *dbx = (struct dbx_symfile_info *)
+				 objfile->sym_stab_info;
+  struct stab_section_info *maybe = dbx->stab_section_info;
+  struct stab_section_info *questionable = 0;
+  int i;
+  char *p;
+
+  /* The ELF symbol info doesn't include path names, so strip the path
+     (if any) from the psymtab filename.  */
+  while (0 != (p = strchr (filename, '/')))
+    filename = p+1;
+
+  /* FIXME:  This linear search could speed up significantly
+     if it was chained in the right order to match how we search it,
+     and if we unchained when we found a match. */
+  for (; maybe; maybe = maybe->next)
+    {
+      if (filename[0] == maybe->filename[0]
+	  && STREQ (filename, maybe->filename))
+	{
+	  /* We found a match.  But there might be several source files
+	     (from different directories) with the same name.  */
+	  if (0 == maybe->found)
+	    break;
+	  questionable = maybe;		/* Might use it later.  */
+	}
+    }
+
+  if (maybe == 0 && questionable != 0)
+    {
+      complain (&stab_info_questionable_complaint, filename);
+      maybe = questionable;
+    }
+
+  if (maybe)
+    {
+      /* Found it!  Allocate a new psymtab struct, and fill it in.  */
+      maybe->found++;
+      pst->section_offsets = (struct section_offsets *)
+	obstack_alloc (&objfile -> psymbol_obstack,
+		       sizeof (struct section_offsets) +
+	       sizeof (pst->section_offsets->offsets) * (SECT_OFF_MAX-1));
+
+      for (i = 0; i < SECT_OFF_MAX; i++)
+	ANOFFSET (pst->section_offsets, i) = maybe->sections[i];
+      return;
+    }
+
+  /* We were unable to find any offsets for this file.  Complain.  */
+  if (dbx->stab_section_info)		/* If there *is* any info, */
+    complain (&stab_info_mismatch_complaint, filename);
+}
+
+/* Register that we are able to handle ELF object file formats.  */
+
+static struct sym_fns elf_sym_fns =
+{
+  bfd_target_elf_flavour,
+  elf_new_init,		/* sym_new_init: init anything gbl to entire symtab */
+  elf_symfile_init,	/* sym_init: read initial info, setup for sym_read() */
+  elf_symfile_read,	/* sym_read: read a symbol file into symtab */
+  elf_symfile_finish,	/* sym_finish: finished with file, cleanup */
+  default_symfile_offsets,
+			/* sym_offsets:  Translate ext. to int. relocation */
+  NULL			/* next: pointer to next struct sym_fns */
+};
+
+void
+_initialize_elfread ()
+{
+  add_symtab_fns (&elf_sym_fns);
+}