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x86: Properly handle __ehdr_start

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After _bfd_i386_elf_convert_load and _bfd_x86_64_elf_convert_load are
removed, elf_i386_convert_load_reloc and elf_x86_64_convert_load_reloc
see __ehdr_start as an undefined symbol when they are called from
check_relocs to convert GOT relocations against local symbols.  But
__ehdr_start will be defined as a hidden symbol by linker at the later
stage if it is referenced.  This patch marks __ehdr_start as a defined
local symbol at the start of check_relocs if it is referenced and not
defined.

bfd/

	PR ld/22115
	* elf32-i386.c (elf_i386_convert_load_reloc): Check linker_def.
	Don't use UNDEFINED_WEAK_RESOLVED_TO_ZERO.
	* elf64-x86-64.c (elf_x86_64_convert_load_reloc): Check
	linker_def.  Don't use UNDEFINED_WEAK_RESOLVED_TO_ZERO.
	* elfxx-x86.c (_bfd_x86_elf_link_check_relocs): Set local_ref
	and linker_def on __ehdr_start if it is referenced and not
	defined.
	(_bfd_x86_elf_link_symbol_references_local): Also set local_ref
	and return TRUE when building executable, if a symbol has
	non-GOT/non-PLT relocations in text section or there is no
	dynamic linker.
	* elfxx-x86.h (elf_x86_link_hash_entry): Add linker_def.

ld/

	PR ld/22115
	* ld-i386/i386.exp: Run PR ld/22115 tests,
	* ld/testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-i386/pr22115-1.s: New file.
	* testsuite/ld-i386/pr22115-1a.d: Likewise.
	* testsuite/ld-i386/pr22115-1b.d: Likewise.
	* testsuite/ld-i386/pr22115-1c.d: Likewise.
	* testsuite/ld-i386/pr22115-1d.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1.s: Likewise.
	* testsuite/ld-x86-64/pr22115-1a-x32.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1a.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1b-x32.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1b.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1c-x32.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1c.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1d-x32.d: Likewise.
	* testsuite/ld-x86-64/pr22115-1d.d: Likewise.
This commit is contained in:
H.J. Lu
2017-09-09 05:05:16 -07:00
parent 90d499086b
commit 0a27fed72d
22 changed files with 237 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
bfd/elf32-i386.c
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@@ -1229,6 +1229,8 @@ elf_i386_convert_load_reloc (bfd *abfd, Elf_Internal_Shdr *symtab_hdr,
unsigned int r_type;
unsigned int r_symndx;
bfd_vma roff = irel->r_offset;
bfd_boolean local_ref;
struct elf_x86_link_hash_entry *eh;
if (roff < 2)
return TRUE;
@@ -1276,6 +1278,8 @@ elf_i386_convert_load_reloc (bfd *abfd, Elf_Internal_Shdr *symtab_hdr,
register. */
to_reloc_32 = !is_pic || baseless;
eh = elf_x86_hash_entry (h);
/* Try to convert R_386_GOT32X. Get the symbol referred to by the
reloc. */
if (h == NULL)
@@ -1290,10 +1294,14 @@ elf_i386_convert_load_reloc (bfd *abfd, Elf_Internal_Shdr *symtab_hdr,
goto convert_load;
}
/* NB: Also set linker_def via SYMBOL_REFERENCES_LOCAL_P. */
local_ref = SYMBOL_REFERENCES_LOCAL_P (link_info, h);
/* Undefined weak symbol is only bound locally in executable
and its reference is resolved as 0. */
if (UNDEFINED_WEAK_RESOLVED_TO_ZERO (link_info, I386_ELF_DATA, TRUE,
elf_x86_hash_entry (h)))
if (h->root.type == bfd_link_hash_undefweak
&& !eh->linker_def
&& local_ref)
{
if (opcode == 0xff)
{
@@ -1316,16 +1324,13 @@ elf_i386_convert_load_reloc (bfd *abfd, Elf_Internal_Shdr *symtab_hdr,
/* We have "call/jmp *foo@GOT[(%reg)]". */
if ((h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& SYMBOL_REFERENCES_LOCAL_P (link_info, h))
&& local_ref)
{
/* The function is locally defined. */
convert_branch:
/* Convert R_386_GOT32X to R_386_PC32. */
if (modrm == 0x15 || (modrm & 0xf8) == 0x90)
{
struct elf_x86_link_hash_entry *eh
= (struct elf_x86_link_hash_entry *) h;
/* Convert to "nop call foo". ADDR_PREFIX_OPCODE
is a nop prefix. */
modrm = 0xe8;
@@ -1381,10 +1386,11 @@ convert_branch:
bfd_elf_record_link_assignment. start_stop is set on
__start_SECNAME/__stop_SECNAME which mark section SECNAME. */
if (h->start_stop
|| eh->linker_def
|| ((h->def_regular
|| h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& SYMBOL_REFERENCES_LOCAL_P (link_info, h)))
&& local_ref))
{
convert_load:
if (opcode == 0x8b)