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authorRichard Henderson <rth@redhat.com>1999-05-03 07:29:11 +0000
committerRichard Henderson <rth@redhat.com>1999-05-03 07:29:11 +0000
commit252b5132c753830d5fd56823373aed85f2a0db63 (patch)
tree1af963bfd8d3e55167b81def4207f175eaff3a56 /bfd/elflink.c
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19990502 sourceware importbinu_ss_19990502
Diffstat (limited to 'bfd/elflink.c')
-rw-r--r--bfd/elflink.c433
1 files changed, 433 insertions, 0 deletions
diff --git a/bfd/elflink.c b/bfd/elflink.c
new file mode 100644
index 0000000..dc0b042
--- /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;
+}