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x86: Properly handle __ehdr_start

Browse Source 
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

16
bfd/ChangeLog
View File

@ -1,3 +1,19 @@
2017-09-09 H.J. Lu <hongjiu.lu@intel.com>
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.
2017-09-08 H.J. Lu <hongjiu.lu@intel.com>
* elfxx-x86.h: Update comments.

20
bfd/elf32-i386.c
View File

@ -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)

16
bfd/elf64-x86-64.c
View File

@ -1537,11 +1537,15 @@ elf_x86_64_convert_load_reloc (bfd *abfd,
GOTPCRELX relocations since we need to modify REX byte.
It is OK convert mov with R_X86_64_GOTPCREL to
R_X86_64_PC32. */
bfd_boolean local_ref;
struct elf_x86_link_hash_entry *eh = elf_x86_hash_entry (h);
/* NB: Also set linker_def via SYMBOL_REFERENCES_LOCAL_P. */
local_ref = SYMBOL_REFERENCES_LOCAL_P (link_info, h);
if ((relocx || opcode == 0x8b)
&& UNDEFINED_WEAK_RESOLVED_TO_ZERO (link_info,
X86_64_ELF_DATA,
TRUE,
elf_x86_hash_entry (h)))
&& (h->root.type == bfd_link_hash_undefweak
&& !eh->linker_def
&& local_ref))
{
if (opcode == 0xff)
{
@ -1568,11 +1572,12 @@ elf_x86_64_convert_load_reloc (bfd *abfd,
/* Avoid optimizing GOTPCREL relocations againt _DYNAMIC since
ld.so may use its link-time address. */
else if (h->start_stop
|| eh->linker_def
|| ((h->def_regular
|| h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& h != htab->elf.hdynamic
&& SYMBOL_REFERENCES_LOCAL_P (link_info, h)))
&& local_ref))
{
/* bfd_link_hash_new or bfd_link_hash_undefined is
set by an assignment in a linker script in
@ -1580,6 +1585,7 @@ elf_x86_64_convert_load_reloc (bfd *abfd,
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_new
|| h->root.type == bfd_link_hash_undefined

45
bfd/elfxx-x86.c
View File

@ -845,12 +845,28 @@ _bfd_x86_elf_link_check_relocs (bfd *abfd, struct bfd_link_info *info)
htab = elf_x86_hash_table (info, bed->target_id);
if (htab)
{
struct elf_link_hash_entry *h
= elf_link_hash_lookup (elf_hash_table (info),
struct elf_link_hash_entry *h;
h = elf_link_hash_lookup (elf_hash_table (info),
htab->tls_get_addr,
FALSE, FALSE, FALSE);
if (h != NULL)
((struct elf_x86_link_hash_entry *) h)->tls_get_addr = 1;
elf_x86_hash_entry (h)->tls_get_addr = 1;
/* "__ehdr_start" will be defined by linker as a hidden symbol
later if it is referenced and not defined. */
h = elf_link_hash_lookup (elf_hash_table (info),
"__ehdr_start",
FALSE, FALSE, FALSE);
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))
{
elf_x86_hash_entry (h)->local_ref = 2;
elf_x86_hash_entry (h)->linker_def = 1;
}
}
}
@ -1671,8 +1687,9 @@ bfd_boolean
_bfd_x86_elf_link_symbol_references_local (struct bfd_link_info *info,
struct elf_link_hash_entry *h)
{
struct elf_x86_link_hash_entry *eh
= (struct elf_x86_link_hash_entry *) h;
struct elf_x86_link_hash_entry *eh = elf_x86_hash_entry (h);
struct elf_x86_link_hash_table *htab
= (struct elf_x86_link_hash_table *) info->hash;
if (eh->local_ref > 1)
return TRUE;
@ -1681,13 +1698,19 @@ _bfd_x86_elf_link_symbol_references_local (struct bfd_link_info *info,
return FALSE;
/* Unversioned symbols defined in regular objects can be forced local
by linker version script. A weak undefined symbol can fored local
if it has non-default visibility or "-z nodynamic-undefined-weak"
is used. */
by linker version script. A weak undefined symbol is forced local
if
1. It has non-default visibility. Or
2. When building executable, it has non-GOT/non-PLT relocations
in text section or there is no dynamic linker. Or
3. or "-z nodynamic-undefined-weak" is used.
*/
if (SYMBOL_REFERENCES_LOCAL (info, h)
|| ((ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
|| info->dynamic_undefined_weak == 0)
&& h->root.type == bfd_link_hash_undefweak)
|| (h->root.type == bfd_link_hash_undefweak
&& (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
|| (bfd_link_executable (info)
&& (htab->interp == NULL || eh->has_non_got_reloc))
|| info->dynamic_undefined_weak == 0))
|| ((h->def_regular || ELF_COMMON_DEF_P (h))
&& h->versioned == unversioned
&& info->version_info != NULL

3
bfd/elfxx-x86.h
View File

@ -108,6 +108,9 @@ struct elf_x86_link_hash_entry
*/
unsigned int local_ref : 2;
/* TRUE if symbol is defined by linker. */
unsigned int linker_def : 1;
/* Terue if symbol is referenced by R_386_GOTOFF relocation. This is
only used by i386. */
unsigned int gotoff_ref : 1;

20
ld/ChangeLog
View File

@ -1,3 +1,23 @@
2017-09-09 H.J. Lu <hongjiu.lu@intel.com>
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.
2017-09-06 H.J. Lu <hongjiu.lu@intel.com>
* testsuite/ld-x86-64/pr19609-2a.d: Updated.

4
ld/testsuite/ld-i386/i386.exp
View File

@ -440,6 +440,10 @@ run_dump_test "pie1"
run_dump_test "pie1-nacl"
run_dump_test "pr21884"
run_dump_test "pr21884-nacl"
run_dump_test "pr22115-1a"
run_dump_test "pr22115-1b"
run_dump_test "pr22115-1c"
run_dump_test "pr22115-1d"
if { !([istarget "i?86-*-linux*"]
|| [istarget "i?86-*-gnu*"]

7
ld/testsuite/ld-i386/pr22115-1.s Normal file
View File

@ -0,0 +1,7 @@
.text
.globl _start
.type _start, @function
_start:
movl __ehdr_start@GOT(%eax), %eax
.size _start, .-_start
.weak __ehdr_start

13
ld/testsuite/ld-i386/pr22115-1a.d Normal file
View File

@ -0,0 +1,13 @@
#source: pr22115-1.s
#as: --32 -mrelax-relocations=yes
#ld: -pie -z text -m elf_i386
#objdump: -dw
.*: +file format .*
Disassembly of section .text:
[a-f0-9]+ <_start>:
+[a-f0-9]+: 8d 80 ([0-9a-f]{2} ){4} * lea -?0x[a-f0-9]+\(%eax\),%eax
#pass

6
ld/testsuite/ld-i386/pr22115-1b.d Normal file
View File

@ -0,0 +1,6 @@
#source: pr22115-1.s
#as: --32 -mrelax-relocations=yes
#ld: -pie -z text -m elf_i386
#readelf: -r
There are no relocations in this file.

13
ld/testsuite/ld-i386/pr22115-1c.d Normal file
View File

@ -0,0 +1,13 @@
#source: pr22115-1.s
#as: --32 -mrelax-relocations=yes
#ld: -pie -z text -m elf_i386 --no-dynamic-linker
#objdump: -dw
.*: +file format .*
Disassembly of section .text:
[a-f0-9]+ <_start>:
+[a-f0-9]+: 8d 80 ([0-9a-f]{2} ){4} * lea -?0x[a-f0-9]+\(%eax\),%eax
#pass

6
ld/testsuite/ld-i386/pr22115-1d.d Normal file
View File

@ -0,0 +1,6 @@
#source: pr22115-1.s
#as: --32 -mrelax-relocations=yes
#ld: -pie -z text -m elf_i386 --no-dynamic-linker
#readelf: -r
There are no relocations in this file.

7
ld/testsuite/ld-x86-64/pr22115-1.s Normal file
View File

@ -0,0 +1,7 @@
.text
.globl _start
.type _start, @function
_start:
movq __ehdr_start@GOTPCREL(%rip), %rax
.size _start, .-_start
.weak __ehdr_start

13
ld/testsuite/ld-x86-64/pr22115-1a-x32.d Normal file
View File

@ -0,0 +1,13 @@
#source: pr22115-1.s
#as: --x32 -mrelax-relocations=yes
#ld: -pie -z text -m elf32_x86_64
#objdump: -dw
.*: +file format .*
Disassembly of section .text:
[a-f0-9]+ <_start>:
+[a-f0-9]+: 48 8d 05 ([0-9a-f]{2} ){4} * lea -?0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <__ehdr_start>
#pass

13
ld/testsuite/ld-x86-64/pr22115-1a.d Normal file
View File

@ -0,0 +1,13 @@
#source: pr22115-1.s
#as: --64 -mrelax-relocations=yes
#ld: -pie -z text -m elf_x86_64
#objdump: -dw
.*: +file format .*
Disassembly of section .text:
[a-f0-9]+ <_start>:
+[a-f0-9]+: 48 8d 05 ([0-9a-f]{2} ){4} * lea -?0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <__ehdr_start>
#pass

6
ld/testsuite/ld-x86-64/pr22115-1b-x32.d Normal file
View File

@ -0,0 +1,6 @@
#source: pr22115-1.s
#as: --x32 -mrelax-relocations=yes
#ld: -pie -z text -m elf32_x86_64
#readelf: -r
There are no relocations in this file.

6
ld/testsuite/ld-x86-64/pr22115-1b.d Normal file
View File

@ -0,0 +1,6 @@
#source: pr22115-1.s
#as: --64 -mrelax-relocations=yes
#ld: -pie -z text -m elf_x86_64
#readelf: -r
There are no relocations in this file.

13
ld/testsuite/ld-x86-64/pr22115-1c-x32.d Normal file
View File

@ -0,0 +1,13 @@
#source: pr22115-1.s
#as: --x32 -mrelax-relocations=yes
#ld: -pie -z text -m elf32_x86_64 --no-dynamic-linker
#objdump: -dw
.*: +file format .*
Disassembly of section .text:
[a-f0-9]+ <_start>:
+[a-f0-9]+: 48 8d 05 ([0-9a-f]{2} ){4} * lea -?0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <__ehdr_start>
#pass

13
ld/testsuite/ld-x86-64/pr22115-1c.d Normal file
View File

@ -0,0 +1,13 @@
#source: pr22115-1.s
#as: --64 -mrelax-relocations=yes
#ld: -pie -z text -m elf_x86_64 --no-dynamic-linker
#objdump: -dw
.*: +file format .*
Disassembly of section .text:
[a-f0-9]+ <_start>:
+[a-f0-9]+: 48 8d 05 ([0-9a-f]{2} ){4} * lea -?0x[a-f0-9]+\(%rip\),%rax # [a-f0-9]+ <__ehdr_start>
#pass

6
ld/testsuite/ld-x86-64/pr22115-1d-x32.d Normal file
View File

@ -0,0 +1,6 @@
#source: pr22115-1.s
#as: --x32 -mrelax-relocations=yes
#ld: -pie -z text -m elf32_x86_64 --no-dynamic-linker
#readelf: -r
There are no relocations in this file.

6
ld/testsuite/ld-x86-64/pr22115-1d.d Normal file
View File

@ -0,0 +1,6 @@
#source: pr22115-1.s
#as: --64 -mrelax-relocations=yes
#ld: -pie -z text -m elf_x86_64 --no-dynamic-linker
#readelf: -r
There are no relocations in this file.

8
ld/testsuite/ld-x86-64/x86-64.exp
View File

@ -369,6 +369,14 @@ run_dump_test "property-x86-shstk5-x32"
run_dump_test "pr21884"
run_dump_test "pr21884-nacl"
run_dump_test "pr22071"
run_dump_test "pr22115-1a"
run_dump_test "pr22115-1a-x32"
run_dump_test "pr22115-1b"
run_dump_test "pr22115-1b-x32"
run_dump_test "pr22115-1c"
run_dump_test "pr22115-1c-x32"
run_dump_test "pr22115-1d"
run_dump_test "pr22115-1d-x32"
if { ![istarget "x86_64-*-linux*"] && ![istarget "x86_64-*-nacl*"]} {
return