[PATCH] D114783: [WIP][ELF] Split scanRelocations into scanRelocations/postScanRelocations

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added a reviewer: peter.smith.
Herald added subscribers: pengfei, dmgreen, kbarton, arichardson, nemanjai, emaste.
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The idea is to make scanRelocations just mark GOT/PLT are needed and let
postScanRelocations do the real work. Arguably the benefit is not large.

- Making it possible to support .plt.got (PR32938): the feature is implementable if the code can know whether GLOB_DAT and JUMP_SLOT are both needed.
- Make non-preemptible IFUNC handling slightly better: avoid setting/clearing sym.gotInIgot

Since this patch moves a large chunk of code out of ELFT templates. My x86-64
executable is actually a few hundred bytes smaller.

We can make copy relocations and canonical PLT entries here as well, then
scanReloc and processRelocAux can avoid the heavylifting code.

Tests are not fixed yet: we build GOT/PLT in the symbol table order,
which may be different from the original order (symbol seen order from relocations).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D114783

Files:
  lld/ELF/Relocations.cpp
  lld/ELF/Relocations.h
  lld/ELF/Symbols.h
  lld/ELF/Writer.cpp
  lld/test/ELF/arm-gnu-ifunc.s
  lld/test/ELF/bsymbolic.s
  lld/test/ELF/dynamic-reloc-weak.s
  lld/test/ELF/gnu-ifunc-i386.s
  lld/test/ELF/ppc64-ifunc.s
  lld/test/ELF/symver.s
  lld/test/ELF/wrap-plt.s
  lld/test/ELF/x86-64-plt.s

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