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BFD: Prevent writing the MIPS _gp_disp symbol into symbol tables

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The _gp_disp is a magic symbol, always implicitly defined by the linker.
It does not make a sense to write it into symbol tables for output files.
Moreover, now if the linker gets a version script, the _gp_disp symbol
gets zero version definition index.  The zero index means[1]:

"The symbol is local, not available outside the object."

But the _gp_disp symbol has GLOBAL binding.  That confuses some tools
like for example the LLD linker when they get such files as inputs.

This patch fixes the problem - it prevents writing the _gp_disp symbol
in regular and dynamic symbol tables.

This was tested by running LD test suite on a mipsel-linux board.

References:

[1] "Linux Standard Base Specification", Section "10.7.2 Symbol
    Version Table", p. 32

2018-05-03  Simon Atanasyan  <simon@atanasyan.com>

bfd/

	* elf32-mips.c: (elf32_mips_fixup_symbol): New function.
	(elf_backend_fixup_symbol): New macro.
	* elfxx-mips.c: (mips_elf_output_extsym): Discard _gp_disp
	handling.
	(_bfd_mips_elf_finish_dynamic_symbol): Likewise.

ld/

	* testsuite/ld-mips-elf/gp-disp-sym.d: New test.
	* testsuite/ld-mips-elf/gp-disp-sym.s: New test source.
	* testsuite/ld-mips-elf/mips-elf.exp: Run the new test.
	* testsuite/ld-mips-elf/mips16-pic-2.ad: Update for _gp_disp
	symbol removal.
	* testsuite/ld-mips-elf/mips16-pic-2.nd: Likewise.
	* testsuite/ld-mips-elf/pic-and-nonpic-3a.dd: Likewise.
	* testsuite/ld-mips-elf/tlslib-o32-hidden.got: Likewise.
	* testsuite/ld-mips-elf/tlslib-o32-ver.got: Likewise.
	* testsuite/ld-mips-elf/tlslib-o32.got: Likewise.
This commit is contained in:
Simon Atanasyan
2018-05-03 17:17:46 +01:00
committed by Maciej W. Rozycki
parent bd732259bd
commit 3be08ea472
13 changed files with 76 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
bfd/ChangeLog
View File

@ -1,3 +1,11 @@
2018-05-03 Simon Atanasyan <simon@atanasyan.com>
* elf32-mips.c: (elf32_mips_fixup_symbol): New function.
(elf_backend_fixup_symbol): New macro.
* elfxx-mips.c: (mips_elf_output_extsym): Discard _gp_disp
handling.
(_bfd_mips_elf_finish_dynamic_symbol): Likewise.
2018-04-30 Francois H. Theron <francois.theron@netronome.com> 2018-04-30 Francois H. Theron <francois.theron@netronome.com>
* Makefile.am: Added NFP files to build. * Makefile.am: Added NFP files to build.

12
bfd/elf32-mips.c
View File

@ -2420,6 +2420,17 @@ elf32_mips_write_core_note (bfd *abfd, char *buf, int *bufsiz, int note_type,
} }
} }
} }
/* Remove the magic _gp_disp symbol from the symbol tables. */
static bfd_boolean
elf32_mips_fixup_symbol (struct bfd_link_info *info,
struct elf_link_hash_entry *h)
{
if (strcmp (h->root.root.string, "_gp_disp") == 0)
_bfd_elf_link_hash_hide_symbol (info, h, TRUE);
return TRUE;
}
/* Depending on the target vector we generate some version of Irix /* Depending on the target vector we generate some version of Irix
executables or "normal" MIPS ELF ABI executables. */ executables or "normal" MIPS ELF ABI executables. */
@ -2523,6 +2534,7 @@ static const struct ecoff_debug_swap mips_elf32_ecoff_debug_swap = {
#define elf_backend_gc_mark_hook _bfd_mips_elf_gc_mark_hook #define elf_backend_gc_mark_hook _bfd_mips_elf_gc_mark_hook
#define elf_backend_copy_indirect_symbol \ #define elf_backend_copy_indirect_symbol \
_bfd_mips_elf_copy_indirect_symbol _bfd_mips_elf_copy_indirect_symbol
#define elf_backend_fixup_symbol elf32_mips_fixup_symbol
#define elf_backend_grok_prstatus elf32_mips_grok_prstatus #define elf_backend_grok_prstatus elf32_mips_grok_prstatus
#define elf_backend_grok_psinfo elf32_mips_grok_psinfo #define elf_backend_grok_psinfo elf32_mips_grok_psinfo
#define elf_backend_ecoff_debug_swap &mips_elf32_ecoff_debug_swap #define elf_backend_ecoff_debug_swap &mips_elf32_ecoff_debug_swap

12
bfd/elfxx-mips.c
View File

@ -2903,12 +2903,6 @@ mips_elf_output_extsym (struct mips_elf_link_hash_entry *h, void *data)
h->esym.asym.value = h->esym.asym.value =
mips_elf_hash_table (einfo->info)->procedure_count; mips_elf_hash_table (einfo->info)->procedure_count;
} }
else if (strcmp (name, "_gp_disp") == 0 && ! NEWABI_P (einfo->abfd))
{
h->esym.asym.sc = scAbs;
h->esym.asym.st = stLabel;
h->esym.asym.value = elf_gp (einfo->abfd);
}
else else
h->esym.asym.sc = scUndefined; h->esym.asym.sc = scUndefined;
} }
@ -10976,12 +10970,6 @@ _bfd_mips_elf_finish_dynamic_symbol (bfd *output_bfd,
sym->st_info = ELF_ST_INFO (STB_GLOBAL, STT_SECTION); sym->st_info = ELF_ST_INFO (STB_GLOBAL, STT_SECTION);
sym->st_value = 1; sym->st_value = 1;
} }
else if (strcmp (name, "_gp_disp") == 0 && ! NEWABI_P (output_bfd))
{
sym->st_shndx = SHN_ABS;
sym->st_info = ELF_ST_INFO (STB_GLOBAL, STT_SECTION);
sym->st_value = elf_gp (output_bfd);
}
else if (SGI_COMPAT (output_bfd)) else if (SGI_COMPAT (output_bfd))
{ {
if (strcmp (name, mips_elf_dynsym_rtproc_names[0]) == 0 if (strcmp (name, mips_elf_dynsym_rtproc_names[0]) == 0

13
ld/ChangeLog
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@ -1,3 +1,16 @@
2018-05-03 Simon Atanasyan <simon@atanasyan.com>
* testsuite/ld-mips-elf/gp-disp-sym.d: New test.
* testsuite/ld-mips-elf/gp-disp-sym.s: New test source.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new test.
* testsuite/ld-mips-elf/mips16-pic-2.ad: Update for _gp_disp
symbol removal.
* testsuite/ld-mips-elf/mips16-pic-2.nd: Likewise.
* testsuite/ld-mips-elf/pic-and-nonpic-3a.dd: Likewise.
* testsuite/ld-mips-elf/tlslib-o32-hidden.got: Likewise.
* testsuite/ld-mips-elf/tlslib-o32-ver.got: Likewise.
* testsuite/ld-mips-elf/tlslib-o32.got: Likewise.
2018-04-27 Maciej W. Rozycki <macro@mips.com> 2018-04-27 Maciej W. Rozycki <macro@mips.com>
* testsuite/ld-mips-elf/bal-jalx-pic.d: Only run for * testsuite/ld-mips-elf/bal-jalx-pic.d: Only run for

9
ld/testsuite/ld-mips-elf/gp-disp-sym.d Normal file
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@ -0,0 +1,9 @@
#name: MIPS _gp_disp removal from symbol tables
#ld: -shared
#objdump: -tT
#target: [check_shared_lib_support]
#failif
#...
.*_gp_disp
#pass

5
ld/testsuite/ld-mips-elf/gp-disp-sym.s Normal file
View File

@ -0,0 +1,5 @@
.global foo
.text
foo:
lui $t0, %hi(_gp_disp)
addi $t0, $t0, %lo(_gp_disp)

4
ld/testsuite/ld-mips-elf/mips-elf.exp
View File

@ -1255,3 +1255,7 @@ run_dump_test "mips-abiflags-1"
run_dump_test "mips-abiflags-1r" run_dump_test "mips-abiflags-1r"
run_dump_test "mips-abiflags-2" run_dump_test "mips-abiflags-2"
run_dump_test "mips-abiflags-2r" run_dump_test "mips-abiflags-2r"
# Test that _gp_disp symbol is not present in symbol tables.
run_dump_test "gp-disp-sym" [list [list as $abi_asflags(o32)] \
[list ld $abi_ldflags(o32)]]

4
ld/testsuite/ld-mips-elf/mips16-pic-2.ad
View File

@ -1,6 +1,6 @@
# [MIPS_GOTSYM, MIPS_SYMTABNO) covers used4...used7. # [MIPS_GOTSYM, MIPS_SYMTABNO) covers used4...used7.
#... #...
.* \(MIPS_SYMTABNO\) * 8 .* \(MIPS_SYMTABNO\) * 7
#... #...
.* \(MIPS_GOTSYM\) * 0x4 .* \(MIPS_GOTSYM\) * 0x3
#pass #pass

10
ld/testsuite/ld-mips-elf/mips16-pic-2.nd
View File

@ -1,9 +1,9 @@
# used8 should come before MIPS_GOTSYM. # used8 should come before MIPS_GOTSYM.
#... #...
+3: 000405bc +36 +FUNC +GLOBAL +DEFAULT .* used8 +2: 000405bc +36 +FUNC +GLOBAL +DEFAULT .* used8
+4: 00040574 +36 +FUNC +GLOBAL +DEFAULT .* used6 +3: 00040574 +36 +FUNC +GLOBAL +DEFAULT .* used6
+5: 00040598 +36 +FUNC +GLOBAL +DEFAULT .* used7 +4: 00040598 +36 +FUNC +GLOBAL +DEFAULT .* used7
+6: 00040550 +36 +FUNC +GLOBAL +DEFAULT .* used5 +5: 00040550 +36 +FUNC +GLOBAL +DEFAULT .* used5
+7: 0004052c +36 +FUNC +GLOBAL +DEFAULT .* used4 +6: 0004052c +36 +FUNC +GLOBAL +DEFAULT .* used4
#pass #pass

2
ld/testsuite/ld-mips-elf/pic-and-nonpic-3a.dd
View File

@ -35,5 +35,5 @@ Disassembly of section \.MIPS\.stubs:
c00: 8f998010 lw t9,-32752\(gp\) c00: 8f998010 lw t9,-32752\(gp\)
c04: 03e07825 move t7,ra c04: 03e07825 move t7,ra
c08: 0320f809 jalr t9 c08: 0320f809 jalr t9
c0c: 24180005 li t8,5 c0c: 24180004 li t8,4
\.\.\. \.\.\.

10
ld/testsuite/ld-mips-elf/tlslib-o32-hidden.got
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@ -4,11 +4,11 @@
DYNAMIC RELOCATION RECORDS DYNAMIC RELOCATION RECORDS
OFFSET TYPE VALUE OFFSET TYPE VALUE
00000000 R_MIPS_NONE \*ABS\* 00000000 R_MIPS_NONE \*ABS\*
000403bc R_MIPS_TLS_TPREL32 \*ABS\* 0004039c R_MIPS_TLS_TPREL32 \*ABS\*
000403c0 R_MIPS_TLS_DTPMOD32 \*ABS\* 000403a0 R_MIPS_TLS_DTPMOD32 \*ABS\*
000403c8 R_MIPS_TLS_DTPMOD32 \*ABS\* 000403a8 R_MIPS_TLS_DTPMOD32 \*ABS\*
Contents of section .got: Contents of section .got:
403b0 00000000 80000000 00000380 00000008 ................ 40390 00000000 80000000 00000360 00000008 ................
403c0 00000000 ffff8004 00000000 00000000 ................ 403a0 00000000 ffff8004 00000000 00000000 ................

12
ld/testsuite/ld-mips-elf/tlslib-o32-ver.got
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@ -4,12 +4,12 @@
DYNAMIC RELOCATION RECORDS DYNAMIC RELOCATION RECORDS
OFFSET TYPE VALUE OFFSET TYPE VALUE
00000000 R_MIPS_NONE \*ABS\* 00000000 R_MIPS_NONE \*ABS\*
000404d8 R_MIPS_TLS_DTPMOD32 \*ABS\* 000404b8 R_MIPS_TLS_DTPMOD32 \*ABS\*
000404d0 R_MIPS_TLS_DTPMOD32 tlsvar_gd@@VER_1 000404b0 R_MIPS_TLS_DTPMOD32 tlsvar_gd@@VER_1
000404d4 R_MIPS_TLS_DTPREL32 tlsvar_gd@@VER_1 000404b4 R_MIPS_TLS_DTPREL32 tlsvar_gd@@VER_1
000404cc R_MIPS_TLS_TPREL32 tlsvar_ie@@VER_1 000404ac R_MIPS_TLS_TPREL32 tlsvar_ie@@VER_1
Contents of section .got: Contents of section .got:
404c0 00000000 80000000 00000490 00000000 ................ 404a0 00000000 80000000 00000470 00000000 ................
404d0 00000000 00000000 00000000 00000000 ................ 404b0 00000000 00000000 00000000 00000000 ................

12
ld/testsuite/ld-mips-elf/tlslib-o32.got
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@ -4,12 +4,12 @@ tmpdir/tlslib-o32.so: file format elf32-tradbigmips
DYNAMIC RELOCATION RECORDS DYNAMIC RELOCATION RECORDS
OFFSET TYPE VALUE OFFSET TYPE VALUE
00000000 R_MIPS_NONE \*ABS\* 00000000 R_MIPS_NONE \*ABS\*
00040448 R_MIPS_TLS_DTPMOD32 \*ABS\* 00040428 R_MIPS_TLS_DTPMOD32 \*ABS\*
00040440 R_MIPS_TLS_DTPMOD32 tlsvar_gd 00040420 R_MIPS_TLS_DTPMOD32 tlsvar_gd
00040444 R_MIPS_TLS_DTPREL32 tlsvar_gd 00040424 R_MIPS_TLS_DTPREL32 tlsvar_gd
0004043c R_MIPS_TLS_TPREL32 tlsvar_ie 0004041c R_MIPS_TLS_TPREL32 tlsvar_ie
Contents of section .got: Contents of section .got:
40430 00000000 80000000 00000400 00000000 ................ 40410 00000000 80000000 000003e0 00000000 ................
40440 00000000 00000000 00000000 00000000 ................ 40420 00000000 00000000 00000000 00000000 ................