[PATCH] D65995: [ELF] Don't special case symbolic relocations with 0 addend to ifunc in writable locations

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added reviewers: grimar, luporl, pcc, peter.smith, ruiu, sfertile.
Herald added subscribers: llvm-commits, jsji, kbarton, arichardson, javed.absar, nemanjai, emaste.
Herald added a reviewer: espindola.
Herald added a project: LLVM.

Currently the following 3 relocation types do not trigger the creation
of a canonical PLT:

1. GOT-generating
2. PLT-generating
3. symbolic relocation with 0 addend in a writable location

3. is used for ifunc function pointers in .data and .toc.

This patch deletes case 3) to simplify the R_*_IRELATIVE generating
logic added in D57371 <https://reviews.llvm.org/D57371>. Other advantages:

- It is guaranteed no more than 1 R_*_IRELATIVE is created for an ifunc.
- PPC64: no need to special case ifunc in toc-indirect to toc-relative relaxation. See D65755 <https://reviews.llvm.org/D65755>


Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D65995

Files:
  ELF/Arch/PPC64.cpp
  ELF/Relocations.cpp
  ELF/Writer.cpp
  test/ELF/aarch64-gnu-ifunc-nonpreemptable2.s
  test/ELF/gnu-ifunc-canon.s
  test/ELF/ppc64-toc-relax-ifunc.s

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