https://sourceware.org/bugzilla/show_bug.cgi?id=31179
Nelson Chu <nelsonc1225 at sourceware dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |FIXED
--- Comment #12 from Nelson Chu <nelsonc1225 at sourceware dot org> ---
commit 73d931e560059a87d76f528fafbb4270a98746bc
Refs: gdb-14-branchpoint-932-g73d931e5600
Author: Nelson Chu <nel...@rivosinc.com>
AuthorDate: Wed Dec 20 10:37:41 2023 +0800
Commit: Nelson Chu <nel...@rivosinc.com>
CommitDate: Thu Dec 28 14:51:50 2023 +0800
RISC-V: PR31179, The SET/ADD/SUB fix breaks ABI compatibility with 2.41
objects
* Problematic fix commit,
2029e13917d53d2289d3ebb390c4f40bd2112d21
RISC-V: Clarify the behaviors of SET/ADD/SUB relocations
* Bugzilla,
https://sourceware.org/bugzilla/show_bug.cgi?id=31179#c5
The addend of SUB_ULEB128 should be zero if using .uleb128, but we make it
non-zero by accident in assembler before. This causes troubles by applying
the above commit, since the calculation is changed to support .reloc *SUB*
relocations with non-zero addend.
We encourage people to rebuild their stuff to get the non-zero addend of
SUB_ULEB128, but that might need some times, so report warnings to inform
people need to rebuild their stuff if --check-uleb128 is enabled.
Since the failed .reloc cases for ADD/SET/SUB/ULEB128 are rarely to use,
it may acceptable that stop supproting them until people rebuld their
stuff,
maybe half-year or a year later. Or maybe we should teach people that
don't
write the .reloc R_RISCV_SUB* with non-zero constant, and then report
warnings/errors in assembler.
bfd/
* elfnn-riscv.c (perform_relocation): Ignore the non-zero addend of
R_RISCV_SUB_ULEB128.
(riscv_elf_relocate_section): Report warnings to inform people need
to rebuild their stuff if --check-uleb128 is enabled. So that can
get the right non-zero addend of R_RISCV_SUB_ULEB128.
* elfxx-riscv.h (struct riscv_elf_params): Added bool
check_uleb128.
ld/
* NEWS: Updated.
* emultempl/riscvelf.em: Added linker risc-v target options,
--[no-]check-uleb128, to enable/disable checking if the addend of
uleb128 is non-zero or not. So that people will know they need to
rebuild the objects with binutils 2.42 and up, to get the right
zero
addend of SUB_ULEB128 relocation, or they may get troubles if using
.reloc.
* ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp: Updated.
* ld/testsuite/ld-riscv-elf/pr31179*: New test cases.
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