Since _GLOBAL_OFFSET_TABLE_ may be referenced implicitly on x86,
checking ref_regular_nonweak leaves the unused _GLOBAL_OFFSET_TABLE_
in output. This patch checks explicit GOT references instead.
ld-i386/discarded1.s and ld-x86-64/discarded1.s are updated to avoid
linker optimization which removes GOT references.
bfd/
PR ld/22782
* elf32-i386.c (elf_i386_check_relocs): Set got_referenced if
_GLOBAL_OFFSET_TABLE_ is referenced or GOT is needed to resolve
undefined weak symbol to 0.
* elf64-x86-64.c (elf_x86_64_check_relocs): Set got_referenced
if _GLOBAL_OFFSET_TABLE_ is referenced.
* elfxx-x86.c (_bfd_x86_elf_size_dynamic_sections): Check
got_referenced instead of ref_regular_nonweak. Remove the
unused _GLOBAL_OFFSET_TABLE_ from symbol table.
* elfxx-x86.h (elf_x86_link_hash_table): Add got_referenced.
ld/
PR ld/22782
* testsuite/ld-i386/discarded1.s: Replace mov with div.
* testsuite/ld-x86-64/discarded1.s: Likewise.
* testsuite/ld-i386/i386.exp: Run pr22782.
* testsuite/ld-i386/load1-nacl.d: Updated for removing
_GLOBAL_OFFSET_TABLE_ from output.
* testsuite/ld-i386/load1.d: Likewise.
* testsuite/ld-x86-64/load1a-nacl.d: Likewise.
* testsuite/ld-x86-64/load1a.d: Likewise.
* testsuite/ld-x86-64/load1b-nacl.d: Likewise.
* testsuite/ld-x86-64/load1b.d: Likewise.
* testsuite/ld-i386/pr22782.d: New file.
* testsuite/ld-i386/pr22782.s: Likewise.
* testsuite/ld-x86-64/pr22782.s: Likewise.
* testsuite/ld-x86-64/pr22782a.d: Likewise.
* testsuite/ld-x86-64/pr22782b.d: Likewise.
* testsuite/ld-x86-64/x86-64.exp: Run pr22782a and pr22782b.
This patch adds support for the R_X86_64_GOTPCRELX and
R_X86_64_REX_GOTPCRELX relocations proposed in
https://groups.google.com/forum/#!topic/x86-64-abi/n9AWHogmVY0
to gas and ld. It updates gas to generate R_X86_64_GOTPCRELX,
R_X86_64_REX_GOTPCRELX if there is a REX prefix, relocation for memory
operand, foo@GOTPCREL(%rip). With the locally defined symbol, foo, we
convert
mov foo@GOTPCREL(%rip), %reg
to
lea foo(%rip), %reg
and convert
call/jmp *foo@GOTPCREL(%rip)
to
nop call foo/jmp foo nop
When PIC is false, convert
test %reg, foo@GOTPCREL(%rip)
to
test $foo, %reg
and convert
binop foo@GOTPCREL(%rip), %reg
to
binop $foo, %reg
where binop is one of adc, add, and, cmp, or, sbb, sub, xor instructions.
bfd/
* elf64-x86-64.c: Include opcode/i386.h.
(x86_64_elf_howto_table): Add R_X86_64_GOTPCRELX and
R_X86_64_REX_GOTPCRELX.
(R_X86_64_standard): Replace R_X86_64_PLT32_BND with
R_X86_64_REX_GOTPCRELX.
(x86_64_reloc_map): Add BFD_RELOC_X86_64_GOTPCRELX and
BFD_RELOC_X86_64_REX_GOTPCRELX.
(need_convert_mov_to_lea): Renamed to ...
(need_convert_load): This.
(elf_x86_64_check_relocs): Handle R_X86_64_GOTPCRELX and
R_X86_64_REX_GOTPCRELX. Replace need_convert_mov_to_lea with
need_convert_load.
(elf_x86_64_gc_sweep_hook): Handle R_X86_64_GOTPCRELX and
R_X86_64_REX_GOTPCRELX.
(elf_x86_64_size_dynamic_sections): Likewise.
(elf_x86_64_relocate_section): Likewise.
(elf_x86_64_convert_mov_to_lea): Renamed to ...
(elf_x86_64_convert_load): This. Replace need_convert_mov_to_lea
with need_convert_load. Support R_X86_64_GOTPCRELX and
R_X86_64_REX_GOTPCRELX transformations.
* reloc.c (BFD_RELOC_X86_64_GOTPCRELX): New.
(BFD_RELOC_X86_64_REX_GOTPCRELX): Likewise.
* bfd-in2.h: Regenerated.
* libbfd.h: Likewise.
gas/
* config/tc-i386.c (tc_i386_fix_adjustable): Handle
BFD_RELOC_X86_64_GOTPCRELX and BFD_RELOC_X86_64_REX_GOTPCRELX.
(tc_gen_reloc): Likewise.
(i386_validate_fix): Generate BFD_RELOC_X86_64_GOTPCRELX or
BFD_RELOC_X86_64_REX_GOTPCRELX if fx_tcbit2 is set.
* config/tc-i386.h (TC_FORCE_RELOCATION_LOCAL): Also return
true for BFD_RELOC_X86_64_GOTPCRELX and
BFD_RELOC_X86_64_REX_GOTPCRELX.
gas/testsuite/
* gas/i386/i386.exp: Run x86-64-gotpcrel.
* gas/i386/x86-64-gotpcrel.d: New file.
* gas/i386/x86-64-gotpcrel.s: Likewise.
* gas/i386/ilp32/x86-64-gotpcrel.d: Likewise.
* gas/i386/x86-64-localpic.d: Replace R_X86_64_GOTPCREL with
R_X86_64_REX_GOTPCRELX.
* gas/i386/ilp32/x86-64-localpic.d: Likewise.
include/elf/
* x86-64.h (R_X86_64_GOTPCRELX): New.
(R_X86_64_REX_GOTPCRELX): Likewise.
ld/testsuite/
* ld-ifunc/ifunc-5r-local-x86-64.d: Replace R_X86_64_GOTPCREL
with R_X86_64_REX_GOTPCRELX.
* ld-x86-64/plt-main1.rd: Likewise.
* ld-x86-64/plt-main3.rd: Likewise.
* ld-x86-64/plt-main4.rd: Likewise.
* ld-x86-64/gotpcrel1.dd: New file.
* ld-x86-64/gotpcrel1.out: Likewise.
* ld-x86-64/gotpcrel1a.S: Likewise.
* ld-x86-64/gotpcrel1b.c: Likewise.
* ld-x86-64/gotpcrel1c.c: Likewise.
* ld-x86-64/gotpcrel1d.S: Likewise.
* ld-x86-64/load1.s: Likewise.
* ld-x86-64/load1a.d: Likewise.
* ld-x86-64/load1b.d: Likewise.
* ld-x86-64/load1c.d: Likewise.
* ld-x86-64/load1d.d: Likewise.
* ld-x86-64/x86-64.exp: Run load1a, load1b, load1c and load1d
tests. Run gotpcrel1 test.
H.J. Lu