56ceb5b540
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.
README for LD
This is the GNU linker. It is distributed with other "binary
utilities" which should be in ../binutils. See ../binutils/README for
more general notes, including where to send bug reports.
There are many features of the linker:
* The linker uses a Binary File Descriptor library (../bfd)
that it uses to read and write object files. This helps
insulate the linker itself from the format of object files.
* The linker supports a number of different object file
formats. It can even handle multiple formats at once:
Read two input formats and write a third.
* The linker can be configured for cross-linking.
* The linker supports a control language.
* There is a user manual (ld.texinfo), as well as the
beginnings of an internals manual (ldint.texinfo).
Installation
============
See ../binutils/README.
If you want to make a cross-linker, you may want to specify
a different search path of -lfoo libraries than the default.
You can do this by setting the LIB_PATH variable in ./Makefile
or using the --with-lib-path configure switch.
To build just the linker, make the target all-ld from the top level
directory (one directory above this one).
Porting to a new target
=======================
See the ldint.texinfo manual.
Reporting bugs etc
===========================
See ../binutils/README.
Known problems
==============
The Solaris linker normally exports all dynamic symbols from an
executable. The GNU linker does not do this by default. This is
because the GNU linker tries to present the same interface for all
similar targets (in this case, all native ELF targets). This does not
matter for normal programs, but it can make a difference for programs
which try to dlopen an executable, such as PERL or Tcl. You can make
the GNU linker export all dynamic symbols with the -E or
--export-dynamic command line option.
HP/UX 9.01 has a shell bug that causes the linker scripts to be
generated incorrectly. The symptom of this appears to be "fatal error
- scanner input buffer overflow" error messages. There are various
workarounds to this:
* Build and install bash, and build with "make SHELL=bash".
* Update to a version of HP/UX with a working shell (e.g., 9.05).
* Replace "(. ${srcdir}/scripttempl/${SCRIPT_NAME}.sc)" in
genscripts.sh with "sh ${srcdir}..." (no parens) and make sure the
emulparams script used exports any shell variables it sets.
Copyright (C) 2012-2015 Free Software Foundation, Inc.
Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.