Initial revision

1 files changed, 433 insertions, 0 deletions

diff --git a/bfd/elflink.c b/bfd/elflink.c
new file mode 100644
index 00000000000..dc0b0428c60
--- /dev/null
+++ b/bfd/elflink.c
@@ -0,0 +1,433 @@
+/* ELF linking support for BFD.
+   Copyright 1995, 1996, 1997 Free Software Foundation, Inc.
+
+This file is part of BFD, the Binary File Descriptor library.
+
+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 "bfd.h"
+#include "sysdep.h"
+#include "bfdlink.h"
+#include "libbfd.h"
+#define ARCH_SIZE 0
+#include "elf-bfd.h"
+
+boolean
+_bfd_elf_create_got_section (abfd, info)
+     bfd *abfd;
+     struct bfd_link_info *info;
+{
+  flagword flags;
+  register asection *s;
+  struct elf_link_hash_entry *h;
+  struct elf_backend_data *bed = get_elf_backend_data (abfd);
+  int ptralign;
+
+  /* This function may be called more than once.  */
+  if (bfd_get_section_by_name (abfd, ".got") != NULL)
+    return true;
+
+  switch (bed->s->arch_size)
+    {
+    case 32: ptralign = 2; break;
+    case 64: ptralign = 3; break;
+    default: abort();
+    }
+
+  flags = (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY
+	   | SEC_LINKER_CREATED);
+
+  s = bfd_make_section (abfd, ".got");
+  if (s == NULL
+      || !bfd_set_section_flags (abfd, s, flags)
+      || !bfd_set_section_alignment (abfd, s, ptralign))
+    return false;
+
+  if (bed->want_got_plt)
+    {
+      s = bfd_make_section (abfd, ".got.plt");
+      if (s == NULL
+	  || !bfd_set_section_flags (abfd, s, flags)
+	  || !bfd_set_section_alignment (abfd, s, ptralign))
+	return false;
+    }
+
+  /* Define the symbol _GLOBAL_OFFSET_TABLE_ at the start of the .got
+     (or .got.plt) section.  We don't do this in the linker script
+     because we don't want to define the symbol if we are not creating
+     a global offset table.  */
+  h = NULL;
+  if (!(_bfd_generic_link_add_one_symbol
+	(info, abfd, "_GLOBAL_OFFSET_TABLE_", BSF_GLOBAL, s,
+	 bed->got_symbol_offset, (const char *) NULL, false,
+	 bed->collect, (struct bfd_link_hash_entry **) &h)))
+    return false;
+  h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
+  h->type = STT_OBJECT;
+
+  if (info->shared
+      && ! _bfd_elf_link_record_dynamic_symbol (info, h))
+    return false;
+
+  elf_hash_table (info)->hgot = h;
+
+  /* The first bit of the global offset table is the header.  */
+  s->_raw_size += bed->got_header_size + bed->got_symbol_offset;
+
+  return true;
+}
+
+
+/* Create dynamic sections when linking against a dynamic object.  */
+
+boolean
+_bfd_elf_create_dynamic_sections (abfd, info)
+     bfd *abfd;
+     struct bfd_link_info *info;
+{
+  flagword flags, pltflags;
+  register asection *s;
+  struct elf_backend_data *bed = get_elf_backend_data (abfd);
+  int ptralign;
+
+  switch (bed->s->arch_size)
+    {
+    case 32: ptralign = 2; break;
+    case 64: ptralign = 3; break;
+    default: abort();
+    }
+
+  /* We need to create .plt, .rel[a].plt, .got, .got.plt, .dynbss, and
+     .rel[a].bss sections.  */
+
+  flags = (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY
+	   | SEC_LINKER_CREATED);
+
+  pltflags = flags;
+  pltflags |= SEC_CODE;
+  if (bed->plt_not_loaded)
+    pltflags &= ~ (SEC_LOAD | SEC_HAS_CONTENTS);
+  if (bed->plt_readonly)
+    pltflags |= SEC_READONLY;
+
+  s = bfd_make_section (abfd, ".plt");
+  if (s == NULL
+      || ! bfd_set_section_flags (abfd, s, pltflags)
+      || ! bfd_set_section_alignment (abfd, s, bed->plt_alignment))
+    return false;
+
+  if (bed->want_plt_sym)
+    {
+      /* Define the symbol _PROCEDURE_LINKAGE_TABLE_ at the start of the
+	 .plt section.  */
+      struct elf_link_hash_entry *h = NULL;
+      if (! (_bfd_generic_link_add_one_symbol
+	     (info, abfd, "_PROCEDURE_LINKAGE_TABLE_", BSF_GLOBAL, s,
+	      (bfd_vma) 0, (const char *) NULL, false,
+	      get_elf_backend_data (abfd)->collect,
+	      (struct bfd_link_hash_entry **) &h)))
+	return false;
+      h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
+      h->type = STT_OBJECT;
+
+      if (info->shared
+	  && ! _bfd_elf_link_record_dynamic_symbol (info, h))
+	return false;
+    }
+
+  s = bfd_make_section (abfd, bed->use_rela_p ? ".rela.plt" : ".rel.plt");
+  if (s == NULL
+      || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
+      || ! bfd_set_section_alignment (abfd, s, ptralign))
+    return false;
+
+  if (! _bfd_elf_create_got_section (abfd, info))
+    return false;
+
+  /* The .dynbss section is a place to put symbols which are defined
+     by dynamic objects, are referenced by regular objects, and are
+     not functions.  We must allocate space for them in the process
+     image and use a R_*_COPY reloc to tell the dynamic linker to
+     initialize them at run time.  The linker script puts the .dynbss
+     section into the .bss section of the final image.  */
+  s = bfd_make_section (abfd, ".dynbss");
+  if (s == NULL
+      || ! bfd_set_section_flags (abfd, s, SEC_ALLOC))
+    return false;
+
+  /* The .rel[a].bss section holds copy relocs.  This section is not
+     normally needed.  We need to create it here, though, so that the
+     linker will map it to an output section.  We can't just create it
+     only if we need it, because we will not know whether we need it
+     until we have seen all the input files, and the first time the
+     main linker code calls BFD after examining all the input files
+     (size_dynamic_sections) the input sections have already been
+     mapped to the output sections.  If the section turns out not to
+     be needed, we can discard it later.  We will never need this
+     section when generating a shared object, since they do not use
+     copy relocs.  */
+  if (! info->shared)
+    {
+      s = bfd_make_section (abfd, bed->use_rela_p ? ".rela.bss" : ".rel.bss");
+      if (s == NULL
+	  || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
+	  || ! bfd_set_section_alignment (abfd, s, ptralign))
+	return false;
+    }
+
+  return true;
+}
+
+
+/* Record a new dynamic symbol.  We record the dynamic symbols as we
+   read the input files, since we need to have a list of all of them
+   before we can determine the final sizes of the output sections.
+   Note that we may actually call this function even though we are not
+   going to output any dynamic symbols; in some cases we know that a
+   symbol should be in the dynamic symbol table, but only if there is
+   one.  */
+
+boolean
+_bfd_elf_link_record_dynamic_symbol (info, h)
+     struct bfd_link_info *info;
+     struct elf_link_hash_entry *h;
+{
+  if (h->dynindx == -1)
+    {
+      struct bfd_strtab_hash *dynstr;
+      char *p, *alc;
+      const char *name;
+      boolean copy;
+      bfd_size_type indx;
+
+      h->dynindx = elf_hash_table (info)->dynsymcount;
+      ++elf_hash_table (info)->dynsymcount;
+
+      dynstr = elf_hash_table (info)->dynstr;
+      if (dynstr == NULL)
+	{
+	  /* Create a strtab to hold the dynamic symbol names.  */
+	  elf_hash_table (info)->dynstr = dynstr = _bfd_elf_stringtab_init ();
+	  if (dynstr == NULL)
+	    return false;
+	}
+
+      /* We don't put any version information in the dynamic string
+         table.  */
+      name = h->root.root.string;
+      p = strchr (name, ELF_VER_CHR);
+      if (p == NULL)
+	{
+	  alc = NULL;
+	  copy = false;
+	}
+      else
+	{
+	  alc = bfd_malloc (p - name + 1);
+	  if (alc == NULL)
+	    return false;
+	  strncpy (alc, name, p - name);
+	  alc[p - name] = '\0';
+	  name = alc;
+	  copy = true;
+	}
+
+      indx = _bfd_stringtab_add (dynstr, name, true, copy);
+
+      if (alc != NULL)
+	free (alc);
+
+      if (indx == (bfd_size_type) -1)
+	return false;
+      h->dynstr_index = indx;
+    }
+
+  return true;
+}
+
+/* Create a special linker section, or return a pointer to a linker section already created  */
+
+elf_linker_section_t *
+_bfd_elf_create_linker_section (abfd, info, which, defaults)
+     bfd *abfd;
+     struct bfd_link_info *info;
+     enum elf_linker_section_enum which;
+     elf_linker_section_t *defaults;
+{
+  bfd *dynobj = elf_hash_table (info)->dynobj;
+  elf_linker_section_t *lsect;
+
+  /* Record the first bfd section that needs the special section */
+  if (!dynobj)
+    dynobj = elf_hash_table (info)->dynobj = abfd;
+
+  /* If this is the first time, create the section */
+  lsect = elf_linker_section (dynobj, which);
+  if (!lsect)
+    {
+      asection *s;
+
+      lsect = (elf_linker_section_t *)
+	bfd_alloc (dynobj, sizeof (elf_linker_section_t));
+
+      *lsect = *defaults;
+      elf_linker_section (dynobj, which) = lsect;
+      lsect->which = which;
+      lsect->hole_written_p = false;
+
+      /* See if the sections already exist */
+      lsect->section = s = bfd_get_section_by_name (dynobj, lsect->name);
+      if (!s || (s->flags & defaults->flags) != defaults->flags)
+	{
+	  lsect->section = s = bfd_make_section_anyway (dynobj, lsect->name);
+
+	  if (s == NULL)
+	    return (elf_linker_section_t *)0;
+
+	  bfd_set_section_flags (dynobj, s, defaults->flags);
+	  bfd_set_section_alignment (dynobj, s, lsect->alignment);
+	}
+      else if (bfd_get_section_alignment (dynobj, s) < lsect->alignment)
+	bfd_set_section_alignment (dynobj, s, lsect->alignment);
+
+      s->_raw_size = align_power (s->_raw_size, lsect->alignment);
+
+      /* Is there a hole we have to provide?  If so check whether the segment is
+	 too big already */
+      if (lsect->hole_size)
+	{
+	  lsect->hole_offset = s->_raw_size;
+	  s->_raw_size += lsect->hole_size;
+	  if (lsect->hole_offset > lsect->max_hole_offset)
+	    {
+	      (*_bfd_error_handler) (_("%s: Section %s is already to large to put hole of %ld bytes in"),
+				     bfd_get_filename (abfd),
+				     lsect->name,
+				     (long)lsect->hole_size);
+
+	      bfd_set_error (bfd_error_bad_value);
+	      return (elf_linker_section_t *)0;
+	    }
+	}
+
+#ifdef DEBUG
+      fprintf (stderr, "Creating section %s, current size = %ld\n",
+	       lsect->name, (long)s->_raw_size);
+#endif
+
+      if (lsect->sym_name)
+	{
+	  struct elf_link_hash_entry *h = NULL;
+#ifdef DEBUG
+	  fprintf (stderr, "Adding %s to section %s\n",
+		   lsect->sym_name,
+		   lsect->name);
+#endif
+	  h = (struct elf_link_hash_entry *)
+	    bfd_link_hash_lookup (info->hash, lsect->sym_name, false, false, false);
+
+	  if ((h == NULL || h->root.type == bfd_link_hash_undefined)
+	      && !(_bfd_generic_link_add_one_symbol (info,
+						     abfd,
+						     lsect->sym_name,
+						     BSF_GLOBAL,
+						     s,
+						     ((lsect->hole_size)
+						      ? s->_raw_size - lsect->hole_size + lsect->sym_offset
+						      : lsect->sym_offset),
+						     (const char *) NULL,
+						     false,
+						     get_elf_backend_data (abfd)->collect,
+						     (struct bfd_link_hash_entry **) &h)))
+	    return (elf_linker_section_t *)0;
+
+	  if ((defaults->which != LINKER_SECTION_SDATA)
+	      && (defaults->which != LINKER_SECTION_SDATA2))
+	    h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_DYNAMIC;
+
+	  h->type = STT_OBJECT;
+	  lsect->sym_hash = h;
+
+	  if (info->shared
+	      && ! _bfd_elf_link_record_dynamic_symbol (info, h))
+	    return (elf_linker_section_t *)0;
+	}
+    }
+
+#if 0
+  /* This does not make sense.  The sections which may exist in the
+     object file have nothing to do with the sections we want to
+     create.  */
+
+  /* Find the related sections if they have been created */
+  if (lsect->bss_name && !lsect->bss_section)
+    lsect->bss_section = bfd_get_section_by_name (dynobj, lsect->bss_name);
+
+  if (lsect->rel_name && !lsect->rel_section)
+    lsect->rel_section = bfd_get_section_by_name (dynobj, lsect->rel_name);
+#endif
+
+  return lsect;
+}
+
+
+/* Find a linker generated pointer with a given addend and type.  */
+
+elf_linker_section_pointers_t *
+_bfd_elf_find_pointer_linker_section (linker_pointers, addend, which)
+     elf_linker_section_pointers_t *linker_pointers;
+     bfd_signed_vma addend;
+     elf_linker_section_enum_t which;
+{
+  for ( ; linker_pointers != NULL; linker_pointers = linker_pointers->next)
+    {
+      if (which == linker_pointers->which && addend == linker_pointers->addend)
+	return linker_pointers;
+    }
+
+  return (elf_linker_section_pointers_t *)0;
+}
+
+
+/* Make the .rela section corresponding to the generated linker section.  */
+
+boolean
+_bfd_elf_make_linker_section_rela (dynobj, lsect, alignment)
+     bfd *dynobj;
+     elf_linker_section_t *lsect;
+     int alignment;
+{
+  if (lsect->rel_section)
+    return true;
+
+  lsect->rel_section = bfd_get_section_by_name (dynobj, lsect->rel_name);
+  if (lsect->rel_section == NULL)
+    {
+      lsect->rel_section = bfd_make_section (dynobj, lsect->rel_name);
+      if (lsect->rel_section == NULL
+	  || ! bfd_set_section_flags (dynobj,
+				      lsect->rel_section,
+				      (SEC_ALLOC
+				       | SEC_LOAD
+				       | SEC_HAS_CONTENTS
+				       | SEC_IN_MEMORY
+				       | SEC_LINKER_CREATED
+				       | SEC_READONLY))
+	  || ! bfd_set_section_alignment (dynobj, lsect->rel_section, alignment))
+	return false;
+    }
+
+  return true;
+}