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tweak __ehdr_start visibility and flags for check_relocs

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bfd/
	* elf-bfd.h (UNDEFWEAK_NO_DYNAMIC_RELOC): Test linker_def.
ld/
	* ldelf.c (ldelf_before_allocation): Don't force __ehdr_start
	local and hidden here..
	* ldlang.c (lang_symbol_tweaks): ..do so here instead and set
	def_regular and linker_def for check_relocs.  New function
	extracted from lang_process.
This commit is contained in:
Alan Modra 2022-01-12 23:42:23 +10:30
parent 1f95afb889
commit 97da0e2677
3 changed files with 42 additions and 11 deletions
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5
bfd/elf-bfd.h
View file

@ -291,9 +291,12 @@ weakdef (struct elf_link_hash_entry *h)
_bfd_elf_symbol_refs_local_p (H, INFO, 1)
/* Whether an undefined weak symbol should resolve to its link-time
value, even in PIC or PIE objects. */
value, even in PIC or PIE objects. The linker_def test is to
handle symbols like __ehdr_start that may be undefweak in early
stages of linking but are guaranteed to be defined later. */
#define UNDEFWEAK_NO_DYNAMIC_RELOC(INFO, H) \
((H)->root.type == bfd_link_hash_undefweak \
&& !(H)->root.linker_def \
&& (ELF_ST_VISIBILITY ((H)->other) != STV_DEFAULT \
|| (INFO)->dynamic_undefined_weak == 0))

5
ld/ldelf.c
View file

@ -1607,11 +1607,6 @@ ldelf_before_allocation (char *audit, char *depaudit,
|| h->root.type == bfd_link_hash_undefweak
|| h->root.type == bfd_link_hash_common))
{
const struct elf_backend_data *bed;
bed = get_elf_backend_data (link_info.output_bfd);
(*bed->elf_backend_hide_symbol) (&link_info, h, true);
if (ELF_ST_VISIBILITY (h->other) != STV_INTERNAL)
h->other = (h->other & ~ELF_ST_VISIBILITY (-1)) | STV_HIDDEN;
/* Don't leave the symbol undefined. Undefined hidden
symbols typically won't have dynamic relocations, but
we most likely will need dynamic relocations for

43
ld/ldlang.c
View file

@ -6994,6 +6994,43 @@ lang_finalize_start_stop (void)
foreach_start_stop (set_start_stop);
}
static void
lang_symbol_tweaks (void)
{
/* Give initial values for __start and __stop symbols, so that ELF
gc_sections will keep sections referenced by these symbols. Must
be done before lang_do_assignments. */
if (config.build_constructors)
lang_init_start_stop ();
/* Make __ehdr_start hidden, and set def_regular even though it is
likely undefined at this stage. For lang_check_relocs. */
if (is_elf_hash_table (link_info.hash)
&& !bfd_link_relocatable (&link_info))
{
struct elf_link_hash_entry *h = (struct elf_link_hash_entry *)
bfd_link_hash_lookup (link_info.hash, "__ehdr_start",
false, false, true);
/* Only adjust the export class if the symbol was referenced
and not defined, otherwise leave it alone. */
if (h != NULL
&& (h->root.type == bfd_link_hash_new
|| h->root.type == bfd_link_hash_undefined
|| h->root.type == bfd_link_hash_undefweak
|| h->root.type == bfd_link_hash_common))
{
const struct elf_backend_data *bed;
bed = get_elf_backend_data (link_info.output_bfd);
(*bed->elf_backend_hide_symbol) (&link_info, h, true);
if (ELF_ST_VISIBILITY (h->other) != STV_INTERNAL)
h->other = (h->other & ~ELF_ST_VISIBILITY (-1)) | STV_HIDDEN;
h->def_regular = 1;
h->root.linker_def = 1;
}
}
}
static void
lang_end (void)
{
@ -8210,11 +8247,7 @@ lang_process (void)
files. */
ldctor_build_sets ();
/* Give initial values for __start and __stop symbols, so that ELF
gc_sections will keep sections referenced by these symbols. Must
be done before lang_do_assignments below. */
if (config.build_constructors)
lang_init_start_stop ();
lang_symbol_tweaks ();
/* PR 13683: We must rerun the assignments prior to running garbage
collection in order to make sure that all symbol aliases are resolved. */