Commit Graph

2 Commits

Author SHA1 Message Date
H.J. Lu
bae420ef26 Optimize x86 GOT32X/GOTPCRELX relocations
R_386_GOT32X, R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX relocations
retrieve the symbol address via its GOT slot.  If the symbol address is
known at the link-time, we can use it directly by changing instruction
encoding.  Indirect branch can only be converted to PC relative direct
branch.  MOV can be changed to LEA or encoded differently with signed
address.  The subset of binary operations can be encoded only with
signed address.

If undefined weak symbol is resolved to zero link-time, we can use it
as address.  Zero addresss can't used with PC relative direct branch
when PIC is true since the current PC is unknown.  In 64-bit, 32-bit
relocation for PC relatiave direct branch to zero may also overflow.

If this optimization causes relocation overflow, --no-relax can be used
to work around it.

bfd/

	PR ld/19609
	* elf32-i386.c (elf_i386_convert_load): Convert to R_386_32 for
	load with locally bound symbols if PIC is false or there is no
	base register.  Optimize branch to 0 if PIC is false.
	(elf_i386_relocate_section): Don't generate dynamic relocations
	against undefined weak symbols if PIC is false.
	* elf64-x86-64.c (elf_x86_64_convert_load): Disable optimization
	if we can't estimate relocation overflow with --no-relax.
	Convert to R_X86_64_32S/R_X86_64_32 for load with locally bound
	symbols if PIC is false.  Optimize branch to 0 if PIC is false.
	(elf_x86_64_relocate_section): Don't generate dynamic relocations
	against undefined weak symbols if PIC is false.

ld/

	PR ld/19609
	* testsuite/ld-i386/got1.dd: Updated.
	* testsuite/ld-i386/lea1c.d: Likewise.
	* testsuite/ld-i386/load1-nacl.d: Likewise.
	* testsuite/ld-i386/load1.d: Likewise.
	* testsuite/ld-i386/load4b.d: Likewise.
	* testsuite/ld-i386/load5b.d: Likewise.
	* testsuite/ld-i386/mov1b.d: Likewise.
	* testsuite/ld-x86-64/mov1b.d: Likewise.
	* testsuite/ld-x86-64/mov1d.d: Likewise.
	* testsuite/ld-ifunc/ifunc-21-i386.d: Likewise.
	* testsuite/ld-ifunc/ifunc-21-x86-64.d: Likewise.
	* testsuite/ld-ifunc/ifunc-22-i386.d: Likewise.
	* testsuite/ld-ifunc/ifunc-22-x86-64.d: Likewise.
	* testsuite/ld-x86-64/gotpcrel1.dd: Likewise.
	* testsuite/ld-x86-64/lea1a.d: Likewise.
	* testsuite/ld-x86-64/lea1b.d: Likewise.
	* testsuite/ld-x86-64/lea1c.d: Likewise.
	* testsuite/ld-x86-64/lea1d.d: Likewise.
	* testsuite/ld-x86-64/lea1e.d: Likewise.
	* testsuite/ld-x86-64/lea1f.d: Likewise.
	* testsuite/ld-x86-64/mov1b.d: Likewise.
	* testsuite/ld-x86-64/mov1d.d: Likewise.
	* testsuite/ld-x86-64/pr13082-3b.d: Likewise.
	* testsuite/ld-x86-64/pr13082-4b.d: Likewise.
	* testsuite/ld-x86-64/lea1.s: Add tests for 32-bit registers.
	* testsuite/ld-i386/pr19609-1.s: New file.
	* testsuite/ld-i386/pr19609-1a.d: Likewise.
	* testsuite/ld-i386/pr19609-1b.d: Likewise.
	* testsuite/ld-i386/pr19609-1c.d: Likewise.
	* testsuite/ld-i386/pr19609-1d.d: Likewise.
	* testsuite/ld-i386/pr19609-1e.d: Likewise.
	* testsuite/ld-i386/pr19609-1f.d: Likewise.
	* testsuite/ld-i386/pr19609-1g.d: Likewise.
	* testsuite/ld-i386/pr19609-1h.d: Likewise.
	* testsuite/ld-i386/pr19609-1i.d: Likewise.
	* testsuite/ld-i386/pr19609-2.s: Likewise.
	* testsuite/ld-i386/pr19609-2a.d: Likewise.
	* testsuite/ld-i386/pr19609-2b.d: Likewise.
	* testsuite/ld-i386/pr19609-2c.d: Likewise.
	* testsuite/ld-i386/undefweak.s: Likewise.
	* testsuite/ld-i386/undefweaka.d: Likewise.
	* testsuite/ld-i386/undefweakb.d: Likewise.
	* testsuite/ld-x86-64/pr13082-3c.d: Likewise.
	* testsuite/ld-x86-64/pr13082-3d.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1.s: Likewise.
	* testsuite/ld-x86-64/pr19609-1a.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1b.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1c.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1d.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1e.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1f.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1g.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1h.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1i.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1j.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1k.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1l.d: Likewise.
	* testsuite/ld-x86-64/pr19609-1m.d: Likewise.
	* testsuite/ld-x86-64/pr19609-2.s: Likewise.
	* testsuite/ld-x86-64/pr19609-2a.d: Likewise.
	* testsuite/ld-x86-64/pr19609-2b.d: Likewise.
	* testsuite/ld-x86-64/pr19609-2c.d: Likewise.
	* testsuite/ld-x86-64/pr19609-2d.d: Likewise.
	* testsuite/ld-x86-64/pr19609-3.s: Likewise.
	* testsuite/ld-x86-64/pr19609-3a.d: Likewise.
	* testsuite/ld-x86-64/pr19609-3b.d: Likewise.
	* testsuite/ld-x86-64/pr19609-4.s: Likewise.
	* testsuite/ld-x86-64/pr19609-4a.d: Likewise.
	* testsuite/ld-x86-64/pr19609-4b.d: Likewise.
	* testsuite/ld-x86-64/pr19609-4c.d: Likewise.
	* testsuite/ld-x86-64/pr19609-4d.d: Likewise.
	* testsuite/ld-x86-64/pr19609-4e.d: Likewise.
	* testsuite/ld-x86-64/pr19609-5.s: Likewise.
	* testsuite/ld-x86-64/pr19609-5a.d: Likewise.
	* testsuite/ld-x86-64/pr19609-5b.d: Likewise.
	* testsuite/ld-x86-64/pr19609-5c.d: Likewise.
	* testsuite/ld-x86-64/pr19609-5d.d: Likewise.
	* testsuite/ld-x86-64/pr19609-5e.d: Likewise.
	* testsuite/ld-x86-64/pr19609-6.s: Likewise.
	* testsuite/ld-x86-64/pr19609-6a.d: Likewise.
	* testsuite/ld-x86-64/pr19609-6b.d: Likewise.
	* testsuite/ld-x86-64/pr19609-6c.d: Likewise.
	* testsuite/ld-x86-64/pr19609-6d.d: Likewise.
	* testsuite/ld-x86-64/pr19609-7.s: Likewise.
	* testsuite/ld-x86-64/pr19609-7a.d: Likewise.
	* testsuite/ld-x86-64/pr19609-7b.d: Likewise.
	* testsuite/ld-x86-64/pr19609-7c.d: Likewise.
	* testsuite/ld-x86-64/pr19609-7d.d: Likewise.
	* testsuite/ld-i386/i386.exp: Run undefweak tests and tests for
	PR ld/19609.
	* testsuite/ld-x86-64/x86-64.exp: Run pr13082-3c, pr13082-3d
	and tests for PR ld/19609.
2016-02-26 09:39:24 -08:00
H.J. Lu
02a866936d Add R_386_GOT32X support to gas and ld
This patch adds support for the R_386_GOT32X relocation proposed in

https://groups.google.com/forum/#!topic/ia32-abi/GbJJskkid4I

to gas and ld.  It updates gas to generate R_386_GOT32X relocation for
memory operand, foo@GOT[(%reg)].  We must encode "mov foo@GOT, %eax"
with the 0x8b opcode, instead of the 0xb8 opcode, so that it can be
transformed to "lea foo, %eax".  With the locally defined symbol, foo,
we convert

   mov foo@GOT[(%reg1)], %reg2
to
   lea foo[@GOTOFF(%reg1)], %reg2

and convert

   call/jmp *foo@GOT[(%reg)]
to

   nop call foo/jmp foo nop

When PIC is false, convert

   test %reg1, foo@GOT[(%reg2)]
to
   test $foo, %reg1

and convert

binop foo@GOT[(%reg1)], %reg2

to

binop $foo, %reg2

where binop is one of adc, add, and, cmp, or, sbb, sub, xor instructions.

bfd/

	* elf32-i386.c: Include opcode/i386.h.
	(elf_howto_table): Add R_386_GOT32X.
	(R_386_ext2): Replace R_386_IRELATIVE with R_386_GOT32X.
	(elf_i386_reloc_type_lookup): Handle BFD_RELOC_386_GOT32X.
	(need_convert_mov_to_lea): Renamed to ...
	(need_convert_load): This.
	(elf_i386_check_relocs): Handle R_386_GOT32X.  Replace
	need_convert_mov_to_lea with need_convert_load.
	(elf_i386_gc_sweep_hook): Handle R_386_GOT32X.
	(elf_i386_size_dynamic_sections): Likewise.
	(elf_i386_relocate_section): Likewise.
	(elf_i386_convert_mov_to_lea): Renamed to ...
	(elf_i386_convert_load): This.  Replace need_convert_mov_to_lea
	with need_convert_load.  Support R_386_GOT32X transformations.
	* reloc.c (BFD_RELOC_386_GOT32X): New.
	* bfd-in2.h: Regenerated.
	* libbfd.h: Likewise.

gas/

	* config/tc-i386.c (tc_i386_fix_adjustable): Handle
	BFD_RELOC_386_GOT32X.
	(tc_gen_reloc): Likewise.
	(match_template): Force 0x8b encoding for "mov foo@GOT, %eax".
	(output_disp): Check for "call/jmp *mem", "mov mem, %reg",
	"test %reg, mem" and "binop mem, %reg" where binop is one of
	adc, add, and, cmp, or, sbb, sub, xor instructions.  Set
	fx_tcbit if the REX prefix is generated.  Set fx_tcbit2 if
	BFD_RELOC_386_GOT32X should be generated.
	(i386_validate_fix): Generate BFD_RELOC_386_GOT32X if fx_tcbit2
	is set.

gas/testsuite/

	* gas/i386/got.d: New file.
	* gas/i386/got.s: Likewise.
	* gas/i386/i386.exp: Run got.
	* gas/i386/localpic.d: Replace R_386_GOT32 with R_386_GOT32X.
	* gas/i386/mixed-mode-reloc32.d: Likewise.
	* gas/i386/reloc32.d: Likewise.

include/elf/

	* i386.h (R_386_GOT32X): New relocation.

ld/testsuite/

	* ld-i386/branch1.d: New file.
	* ld-i386/branch1.s: Likewise.
	* ld-i386/call1.d: Likewise.
	* ld-i386/call1.s: Likewise.
	* ld-i386/call2.d: Likewise.
	* ld-i386/call2.s: Likewise.
	* ld-i386/got1.dd: Likewise.
	* ld-i386/got1.out: Likewise.
	* ld-i386/got1a.S: Likewise.
	* ld-i386/got1b.c: Likewise.
	* ld-i386/got1c.c: Likewise.
	* ld-i386/got1d.S: Likewise.
	* ld-i386/jmp1.d: Likewise.
	* ld-i386/jmp1.s: Likewise.
	* ld-i386/jmp2.d: Likewise.
	* ld-i386/jmp2.s: Likewise.
	* ld-i386/load1.d: Likewise.
	* ld-i386/load1.s: Likewise.
	* ld-i386/load2.d: Likewise.
	* ld-i386/load2.s: Likewise.
	* ld-i386/load3.d: Likewise.
	* ld-i386/load3.s: Likewise.
	* ld-i386/load4.s: Likewise.
	* ld-i386/load4a.d: Likewise.
	* ld-i386/load4b.d: Likewise.
	* ld-i386/load5.s: Likewise.
	* ld-i386/load5a.d: Likewise.
	* ld-i386/load5b.d: Likewise.
	* ld-i386/load6.d: Likewise.
	* ld-i386/load6.s: Likewise.
	* ld-i386/i386.exp: Run branch1, call1, call2, jmp1, jmp2,
	load1, load2, load3, load4a, load4b, load5a, load5b and load6
	tests.  Run got1 test.
2015-10-22 04:47:07 -07:00