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.
Since __start_XXX and __stop_XXX symbols aren't defined when address
load is being converted, we need to check if there is an XXX output
section to get their section and value. This patch adds a new function,
bfd_link_get_defined_symbol, to search for the XXX output section to
check if __start_XXX and __stop_XXX symbols are defined.
bfd/
PR ld/19171
* elf32-i386.c (elf_i386_convert_load): Call
bfd_link_get_defined_symbol to check if a symbol is defined.
* elf64-x86-64.c (elf_x86_64_convert_load): Call
bfd_link_get_defined_symbol to get defined symbol section and
value.
* linker.c (bfd_link_get_defined_symbol): New function.
* bfd-in2.h: Regenerated.
ld/testsuite/
PR ld/19171
* ld-i386/lea1.s: Add tests for address load of __start_XXX
and __stop_XXX.
* ld-i386/mov1.s: Likewise.
* ld-x86-64/lea1.s: Likewise.
* ld-x86-64/mov1.s: Likewise.
* ld-i386/lea1a.d: Updated.
* ld-i386/lea1b.d: Likewise.
* ld-i386/lea1c.d: Likewise.
* ld-i386/mov1a.d: Likewise.
* ld-i386/mov1b.d: Likewise.
* ld-x86-64/lea1a.d: Likewise.
* ld-x86-64/lea1b.d: Likewise.
* ld-x86-64/lea1c.d: Likewise.
* ld-x86-64/lea1d.d: Likewise.
* ld-x86-64/lea1e.d: Likewise.
* ld-x86-64/lea1f.d: Likewise.
* ld-x86-64/mov1a.d: Likewise.
* ld-x86-64/mov1b.d: Likewise.
* ld-x86-64/mov1c.d: Likewise.
* ld-x86-64/mov1d.d: Likewise.
There is no need to check def_regular when converting mov to lea for
loading address of local symbols since def_regular may be false for
common symbols and SYMBOL_REFERENCES_LOCAL is sufficient.
bfd/
* elf32-i386.c (elf_i386_convert_mov_to_lea): Don't check
def_regular.
* elf64-x86-64.c (elf_x86_64_convert_mov_to_lea): Likewise.
ld/testsuite/
* ld-i386/lea1.s: Add a test for loading address of local common
symbol.
* ld-x86-64/lea1.s: Likewise.
* ld-i386/lea1a.d: Updated.
* ld-i386/lea1b.d: Likewise.
* ld-i386/lea1c.d: Likewise.
* ld-x86-64/lea1a.d: Likewise.
* ld-x86-64/lea1b.d: Likewise.
* ld-x86-64/lea1c.d: Likewise.
* ld-x86-64/lea1d.d: Likewise.
* ld-x86-64/lea1e.d: Likewise.
* ld-x86-64/lea1f.d: Likewise.
H.J. Lu