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| author | Jens Remus <jremus@linux.ibm.com> | 2025-10-16 11:06:17 +0200 |
|---|---|---|
| committer | Jens Remus <jremus@linux.ibm.com> | 2025-10-16 11:06:17 +0200 |
| commit | ad8434760ee1124a402705c8e815a9ba30eb7533 (patch) | |
| tree | f99f94e7038cf4333d3376801537320f3c3e5842 /gdb/python/py-instruction.c | |
| parent | 9c5a8b25703c9b316eeefb1acf87df34279c328b (diff) | |
| download | binutils-ad8434760ee1124a402705c8e815a9ba30eb7533.zip binutils-ad8434760ee1124a402705c8e815a9ba30eb7533.tar.gz binutils-ad8434760ee1124a402705c8e815a9ba30eb7533.tar.bz2 | |
s390: Rewrite emitted relocations when rewriting instructions
When the linker rewrites instructions it may need to rewrite the
associated relocations, so that when emitted with option --emit-relocs,
they make sense with the rewritten instructions. Otherwise post link
analysis and optimization tools may not be able to perform correct
modifications of executables.
Under certain conditions the linker rewrites:
- GOT access using lgrl to larl, changing the GOTENT to a PC32DBL reloc
- GOT access using lg to larl, changing the GOT20 to a PC32DBL reloc
- Relative long addressing instructions of weak symbols, which
definitively resolve to zero, to either (1) load address of zero,
(2) a NOP, or (3) a trapping instruction.
In case of a rewrite of GOT access using lgrl/lg to larl emit the
PC32DBL relocation. In case of a rewrite of relative long addressing
instructions of weak symbols, which definitively resolve to zero, emit
a NONE relocation and reset the symbol table index and addend. Update
the gotreloc* and weakundef* tests to check for the respective
relocations.
This aligns with how GNU linker behaves on x86-64, when rewriting
instructions/relocations in elf_x86_64_convert_load_reloc().
bfd/
* elf64-s390.c (elf_s390_relocate_section): Rewrite emitted
relocations when rewriting instructions.
* elf32-s390.c (elf_s390_relocate_section): Likewise.
ld/testsuite/
* ld-s390/s390.exp: Link gotreloc* and weakundef* tests with
option --emit-relocs.
* ld-s390/gotreloc_31-1.dd: Expect rewritten instructions to be
accompanied by a PC32DBL or NONE relocation respectively.
* ld-s390/gotreloc_31-no-pie-1.dd: Likewise.
* ld-s390/gotreloc_64-no-pie-1.dd: Likewise.
* ld-s390/gotreloc_64-norelro-1.dd: Likewise.
* ld-s390/gotreloc_64-relro-1.dd: Likewise.
* ld-s390/weakundef-1.dd: Likewise.
* ld-s390/weakundef-2.dd: Likewise.
Fixes: a63cc5f70ca6 ("Rewrite GOT accesses using larl if possible")
Fixes: 896a639babe2 ("s390: Avoid reloc overflows on undefined weak symbols")
Fixes: 6f8b365b653d ("s390: Avoid reloc overflows on undefined weak symbols (cont)")
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Diffstat (limited to 'gdb/python/py-instruction.c')
0 files changed, 0 insertions, 0 deletions