/* linker.c -- BFD linker routines
Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
- 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
Free Software Foundation, Inc.
Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support
archive and decide which elements of the archive should be
included in the link. For each such element it must call the
<<add_archive_element>> linker callback, and it must add the
- symbols from the object file to the linker hash table.
+ symbols from the object file to the linker hash table. (The
+ callback may in fact indicate that a replacement BFD should be
+ used, in which case the symbols from that BFD should be added
+ to the linker hash table instead.)
@findex _bfd_generic_link_add_archive_symbols
In most cases the work of looking through the symbols in the
element should be included in the link. If the element is to
be included, the <<add_archive_element>> linker callback
routine must be called with the element as an argument, and
- the elements symbols must be added to the linker hash table
+ the element's symbols must be added to the linker hash table
just as though the element had itself been passed to the
- <<_bfd_link_add_symbols>> function.
+ <<_bfd_link_add_symbols>> function. The <<add_archive_element>>
+ callback has the option to indicate that it would like to
+ replace the element archive with a substitute BFD, in which
+ case it is the symbols of that substitute BFD that must be
+ added to the linker hash table instead.
When the a.out <<_bfd_link_add_symbols>> function receives an
archive, it calls <<_bfd_generic_link_add_archive_symbols>>
symbol) it calls the <<add_archive_element>> callback and then
<<aout_link_check_archive_element>> calls
<<aout_link_add_symbols>> to actually add the symbols to the
- linker hash table.
+ linker hash table - possibly those of a substitute BFD, if the
+ <<add_archive_element>> callback avails itself of that option.
The ECOFF back end is unusual in that it does not normally
call <<_bfd_generic_link_add_archive_symbols>>, because ECOFF
struct bfd_link_hash_entry *h = (struct bfd_link_hash_entry *) entry;
/* Initialize the local fields. */
- h->type = bfd_link_hash_new;
- memset (&h->u.undef.next, 0,
- (sizeof (struct bfd_link_hash_entry)
- - offsetof (struct bfd_link_hash_entry, u.undef.next)));
+ memset ((char *) &h->root + sizeof (h->root), 0,
+ sizeof (*h) - sizeof (h->root));
}
return entry;
return bfd_link_hash_lookup (info->hash, string, create, copy, follow);
}
-/* Traverse a generic link hash table. The only reason this is not a
- macro is to do better type checking. This code presumes that an
- argument passed as a struct bfd_hash_entry * may be caught as a
- struct bfd_link_hash_entry * with no explicit cast required on the
- call. */
+/* Traverse a generic link hash table. Differs from bfd_hash_traverse
+ in the treatment of warning symbols. When warning symbols are
+ created they replace the real symbol, so you don't get to see the
+ real symbol in a bfd_hash_travere. This traversal calls func with
+ the real symbol. */
void
bfd_link_hash_traverse
- (struct bfd_link_hash_table *table,
+ (struct bfd_link_hash_table *htab,
bfd_boolean (*func) (struct bfd_link_hash_entry *, void *),
void *info)
{
- bfd_hash_traverse (&table->table,
- (bfd_boolean (*) (struct bfd_hash_entry *, void *)) func,
- info);
+ unsigned int i;
+
+ htab->table.frozen = 1;
+ for (i = 0; i < htab->table.size; i++)
+ {
+ struct bfd_link_hash_entry *p;
+
+ p = (struct bfd_link_hash_entry *) htab->table.table[i];
+ for (; p != NULL; p = (struct bfd_link_hash_entry *) p->root.next)
+ if (!(*func) (p->type == bfd_link_hash_warning ? p->u.i.link : p, info))
+ goto out;
+ }
+ out:
+ htab->table.frozen = 0;
}
/* Add a symbol to the linker hash table undefs list. */
included. CHECKFN should set *PNEEDED to TRUE if the object file
should be included, and must also call the bfd_link_info
add_archive_element callback function and handle adding the symbols
- to the global hash table. CHECKFN should only return FALSE if some
- sort of error occurs.
+ to the global hash table. CHECKFN must notice if the callback
+ indicates a substitute BFD, and arrange to add those symbols instead
+ if it does so. CHECKFN should only return FALSE if some sort of
+ error occurs.
For some formats, such as a.out, it is possible to look through an
object file but not actually include it in the link. The
{
bfd_size_type symcount;
asymbol **symbols;
+ bfd *oldbfd = abfd;
/* This object file defines this symbol, so pull it in. */
- if (! (*info->callbacks->add_archive_element) (info, abfd,
- bfd_asymbol_name (p)))
+ if (!(*info->callbacks
+ ->add_archive_element) (info, abfd, bfd_asymbol_name (p),
+ &abfd))
+ return FALSE;
+ /* Potentially, the add_archive_element hook may have set a
+ substitute BFD for us. */
+ if (abfd != oldbfd
+ && !bfd_generic_link_read_symbols (abfd))
return FALSE;
symcount = _bfd_generic_link_get_symcount (abfd);
symbols = _bfd_generic_link_get_symbols (abfd);
/* This symbol was created as undefined from outside
BFD. We assume that we should link in the object
file. This is for the -u option in the linker. */
- if (! (*info->callbacks->add_archive_element)
- (info, abfd, bfd_asymbol_name (p)))
+ if (!(*info->callbacks
+ ->add_archive_element) (info, abfd, bfd_asymbol_name (p),
+ &abfd))
return FALSE;
+ /* Potentially, the add_archive_element hook may have set a
+ substitute BFD for us. But no symbols are going to get
+ registered by anything we're returning to from here. */
*pneeded = TRUE;
return TRUE;
}
else
h->u.c.p->section = bfd_make_section_old_way (symbfd,
p->section->name);
- h->u.c.p->section->flags = SEC_ALLOC;
+ h->u.c.p->section->flags |= SEC_ALLOC;
}
else
{
struct bfd_link_hash_entry *h;
bfd_boolean cycle;
+ BFD_ASSERT (section != NULL);
+
if (bfd_is_ind_section (section)
|| (flags & BSF_INDIRECT) != 0)
row = INDR_ROW;
|| (info->notice_hash != NULL
&& bfd_hash_lookup (info->notice_hash, name, FALSE, FALSE) != NULL))
{
- if (! (*info->callbacks->notice) (info, h->root.string, abfd, section,
- value))
+ if (! (*info->callbacks->notice) (info, h,
+ abfd, section, value, flags, string))
return FALSE;
}
/* Make a new weak undefined symbol. */
h->type = bfd_link_hash_undefweak;
h->u.undef.abfd = abfd;
- h->u.undef.weak = abfd;
break;
case CDEF:
previously common. */
BFD_ASSERT (h->type == bfd_link_hash_common);
if (! ((*info->callbacks->multiple_common)
- (info, h->root.string,
- h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
- abfd, bfd_link_hash_defined, 0)))
+ (info, h, abfd, bfd_link_hash_defined, 0)))
return FALSE;
/* Fall through. */
case DEF:
if (section == bfd_com_section_ptr)
{
h->u.c.p->section = bfd_make_section_old_way (abfd, "COMMON");
- h->u.c.p->section->flags = SEC_ALLOC;
+ h->u.c.p->section->flags |= SEC_ALLOC;
}
else if (section->owner != abfd)
{
h->u.c.p->section = bfd_make_section_old_way (abfd,
section->name);
- h->u.c.p->section->flags = SEC_ALLOC;
+ h->u.c.p->section->flags |= SEC_ALLOC;
}
else
h->u.c.p->section = section;
two sizes, and use the section required by the larger symbol. */
BFD_ASSERT (h->type == bfd_link_hash_common);
if (! ((*info->callbacks->multiple_common)
- (info, h->root.string,
- h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
- abfd, bfd_link_hash_common, value)))
+ (info, h, abfd, bfd_link_hash_common, value)))
return FALSE;
if (value > h->u.c.size)
{
{
h->u.c.p->section
= bfd_make_section_old_way (abfd, "COMMON");
- h->u.c.p->section->flags = SEC_ALLOC;
+ h->u.c.p->section->flags |= SEC_ALLOC;
}
else if (section->owner != abfd)
{
h->u.c.p->section
= bfd_make_section_old_way (abfd, section->name);
- h->u.c.p->section->flags = SEC_ALLOC;
+ h->u.c.p->section->flags |= SEC_ALLOC;
}
else
h->u.c.p->section = section;
break;
case CREF:
- {
- bfd *obfd;
-
- /* We have found a common definition for a symbol which
- was already defined. FIXME: It would nice if we could
- report the BFD which defined an indirect symbol, but we
- don't have anywhere to store the information. */
- if (h->type == bfd_link_hash_defined
- || h->type == bfd_link_hash_defweak)
- obfd = h->u.def.section->owner;
- else
- obfd = NULL;
- if (! ((*info->callbacks->multiple_common)
- (info, h->root.string, obfd, h->type, 0,
- abfd, bfd_link_hash_common, value)))
- return FALSE;
- }
+ /* We have found a common definition for a symbol which
+ was already defined. */
+ if (! ((*info->callbacks->multiple_common)
+ (info, h, abfd, bfd_link_hash_common, value)))
+ return FALSE;
break;
case MIND:
/* Fall through. */
case MDEF:
/* Handle a multiple definition. */
- if (!info->allow_multiple_definition)
- {
- asection *msec = NULL;
- bfd_vma mval = 0;
-
- switch (h->type)
- {
- case bfd_link_hash_defined:
- msec = h->u.def.section;
- mval = h->u.def.value;
- break;
- case bfd_link_hash_indirect:
- msec = bfd_ind_section_ptr;
- mval = 0;
- break;
- default:
- abort ();
- }
-
- /* Ignore a redefinition of an absolute symbol to the
- same value; it's harmless. */
- if (h->type == bfd_link_hash_defined
- && bfd_is_abs_section (msec)
- && bfd_is_abs_section (section)
- && value == mval)
- break;
-
- if (! ((*info->callbacks->multiple_definition)
- (info, h->root.string, msec->owner, msec, mval,
- abfd, section, value)))
- return FALSE;
- }
+ if (! ((*info->callbacks->multiple_definition)
+ (info, h, abfd, section, value)))
+ return FALSE;
break;
case CIND:
/* Create an indirect symbol from an existing common symbol. */
BFD_ASSERT (h->type == bfd_link_hash_common);
if (! ((*info->callbacks->multiple_common)
- (info, h->root.string,
- h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
- abfd, bfd_link_hash_indirect, 0)))
+ (info, h, abfd, bfd_link_hash_indirect, 0)))
return FALSE;
/* Fall through. */
case IND:
(struct generic_write_global_symbol_info *) data;
asymbol *sym;
- if (h->root.type == bfd_link_hash_warning)
- h = (struct generic_link_hash_entry *) h->root.u.i.link;
-
if (h->written)
return TRUE;
bfd_section_already_linked
SYNOPSIS
- void bfd_section_already_linked (bfd *abfd, asection *sec,
- struct bfd_link_info *info);
+ bfd_boolean bfd_section_already_linked (bfd *abfd,
+ asection *sec,
+ struct bfd_link_info *info);
DESCRIPTION
- Check if @var{sec} has been already linked during a reloceatable
- or final link.
+ Check if @var{data} has been already linked during a reloceatable
+ or final link. Return TRUE if it has.
.#define bfd_section_already_linked(abfd, sec, info) \
. BFD_SEND (abfd, _section_already_linked, (abfd, sec, info))
bfd_hash_table_free (&_bfd_section_already_linked_table);
}
+/* Report warnings as appropriate for duplicate section SEC.
+ Return FALSE if we decide to keep SEC after all. */
+
+bfd_boolean
+_bfd_handle_already_linked (asection *sec,
+ struct bfd_section_already_linked *l,
+ struct bfd_link_info *info)
+{
+ switch (sec->flags & SEC_LINK_DUPLICATES)
+ {
+ default:
+ abort ();
+
+ case SEC_LINK_DUPLICATES_DISCARD:
+ /* If we found an LTO IR match for this comdat group on
+ the first pass, replace it with the LTO output on the
+ second pass. We can't simply choose real object
+ files over IR because the first pass may contain a
+ mix of LTO and normal objects and we must keep the
+ first match, be it IR or real. */
+ if (info->loading_lto_outputs
+ && (l->sec->owner->flags & BFD_PLUGIN) != 0)
+ {
+ l->sec = sec;
+ return FALSE;
+ }
+ break;
+
+ case SEC_LINK_DUPLICATES_ONE_ONLY:
+ info->callbacks->einfo
+ (_("%B: ignoring duplicate section `%A'\n"),
+ sec->owner, sec);
+ break;
+
+ case SEC_LINK_DUPLICATES_SAME_SIZE:
+ if ((l->sec->owner->flags & BFD_PLUGIN) != 0)
+ ;
+ else if (sec->size != l->sec->size)
+ info->callbacks->einfo
+ (_("%B: duplicate section `%A' has different size\n"),
+ sec->owner, sec);
+ break;
+
+ case SEC_LINK_DUPLICATES_SAME_CONTENTS:
+ if ((l->sec->owner->flags & BFD_PLUGIN) != 0)
+ ;
+ else if (sec->size != l->sec->size)
+ info->callbacks->einfo
+ (_("%B: duplicate section `%A' has different size\n"),
+ sec->owner, sec);
+ else if (sec->size != 0)
+ {
+ bfd_byte *sec_contents, *l_sec_contents = NULL;
+
+ if (!bfd_malloc_and_get_section (sec->owner, sec, &sec_contents))
+ info->callbacks->einfo
+ (_("%B: could not read contents of section `%A'\n"),
+ sec->owner, sec);
+ else if (!bfd_malloc_and_get_section (l->sec->owner, l->sec,
+ &l_sec_contents))
+ info->callbacks->einfo
+ (_("%B: could not read contents of section `%A'\n"),
+ l->sec->owner, l->sec);
+ else if (memcmp (sec_contents, l_sec_contents, sec->size) != 0)
+ info->callbacks->einfo
+ (_("%B: duplicate section `%A' has different contents\n"),
+ sec->owner, sec);
+
+ if (sec_contents)
+ free (sec_contents);
+ if (l_sec_contents)
+ free (l_sec_contents);
+ }
+ break;
+ }
+
+ /* Set the output_section field so that lang_add_section
+ does not create a lang_input_section structure for this
+ section. Since there might be a symbol in the section
+ being discarded, we must retain a pointer to the section
+ which we are really going to use. */
+ sec->output_section = bfd_abs_section_ptr;
+ sec->kept_section = l->sec;
+ return TRUE;
+}
+
/* This is used on non-ELF inputs. */
-void
-_bfd_generic_section_already_linked (bfd *abfd, asection *sec,
+bfd_boolean
+_bfd_generic_section_already_linked (bfd *abfd ATTRIBUTE_UNUSED,
+ asection *sec,
struct bfd_link_info *info)
{
- flagword flags;
const char *name;
struct bfd_section_already_linked *l;
struct bfd_section_already_linked_hash_entry *already_linked_list;
- flags = sec->flags;
- if ((flags & SEC_LINK_ONCE) == 0)
- return;
+ if ((sec->flags & SEC_LINK_ONCE) == 0)
+ return FALSE;
+
+ /* The generic linker doesn't handle section groups. */
+ if ((sec->flags & SEC_GROUP) != 0)
+ return FALSE;
/* FIXME: When doing a relocatable link, we may have trouble
copying relocations in other sections that refer to local symbols
already_linked_list = bfd_section_already_linked_table_lookup (name);
- for (l = already_linked_list->entry; l != NULL; l = l->next)
+ l = already_linked_list->entry;
+ if (l != NULL)
{
- bfd_boolean skip = FALSE;
- struct coff_comdat_info *s_comdat
- = bfd_coff_get_comdat_section (abfd, sec);
- struct coff_comdat_info *l_comdat
- = bfd_coff_get_comdat_section (l->sec->owner, l->sec);
-
- /* We may have 3 different sections on the list: group section,
- comdat section and linkonce section. SEC may be a linkonce or
- comdat section. We always ignore group section. For non-COFF
- inputs, we also ignore comdat section.
-
- FIXME: Is that safe to match a linkonce section with a comdat
- section for COFF inputs? */
- if ((l->sec->flags & SEC_GROUP) != 0)
- skip = TRUE;
- else if (bfd_get_flavour (abfd) == bfd_target_coff_flavour)
- {
- if (s_comdat != NULL
- && l_comdat != NULL
- && strcmp (s_comdat->name, l_comdat->name) != 0)
- skip = TRUE;
- }
- else if (l_comdat != NULL)
- skip = TRUE;
-
- if (!skip)
- {
- /* The section has already been linked. See if we should
- issue a warning. */
- switch (flags & SEC_LINK_DUPLICATES)
- {
- default:
- abort ();
-
- case SEC_LINK_DUPLICATES_DISCARD:
- break;
-
- case SEC_LINK_DUPLICATES_ONE_ONLY:
- (*_bfd_error_handler)
- (_("%B: warning: ignoring duplicate section `%A'\n"),
- abfd, sec);
- break;
-
- case SEC_LINK_DUPLICATES_SAME_CONTENTS:
- /* FIXME: We should really dig out the contents of both
- sections and memcmp them. The COFF/PE spec says that
- the Microsoft linker does not implement this
- correctly, so I'm not going to bother doing it
- either. */
- /* Fall through. */
- case SEC_LINK_DUPLICATES_SAME_SIZE:
- if (sec->size != l->sec->size)
- (*_bfd_error_handler)
- (_("%B: warning: duplicate section `%A' has different size\n"),
- abfd, sec);
- break;
- }
-
- /* Set the output_section field so that lang_add_section
- does not create a lang_input_section structure for this
- section. Since there might be a symbol in the section
- being discarded, we must retain a pointer to the section
- which we are really going to use. */
- sec->output_section = bfd_abs_section_ptr;
- sec->kept_section = l->sec;
-
- return;
- }
+ /* The section has already been linked. See if we should
+ issue a warning. */
+ return _bfd_handle_already_linked (sec, l, info);
}
/* This is the first section with this name. Record it. */
- if (! bfd_section_already_linked_table_insert (already_linked_list, sec))
+ if (!bfd_section_already_linked_table_insert (already_linked_list, sec))
info->callbacks->einfo (_("%F%P: already_linked_table: %E\n"));
+ return FALSE;
}
/* Convert symbols in excluded output sections to use a kept section. */
{
bfd *obfd = (bfd *) data;
- if (h->type == bfd_link_hash_warning)
- h = h->u.i.link;
-
if (h->type == bfd_link_hash_defined
|| h->type == bfd_link_hash_defweak)
{
return NULL;
}
+
+/*
+FUNCTION
+ bfd_hide_sym_by_version
+
+SYNOPSIS
+ bfd_boolean bfd_hide_sym_by_version
+ (struct bfd_elf_version_tree *verdefs, const char *sym_name);
+
+DESCRIPTION
+ Search an elf version script tree for symbol versioning
+ info for a given symbol. Return TRUE if the symbol is hidden.
+
+*/
+
+bfd_boolean
+bfd_hide_sym_by_version (struct bfd_elf_version_tree *verdefs,
+ const char *sym_name)
+{
+ bfd_boolean hidden = FALSE;
+ bfd_find_version_for_sym (verdefs, sym_name, &hidden);
+ return hidden;
+}