[PATCH] D57371: [wip] ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible.

[Peter Collingbourne via Phabricator via llvm-commits]

pcc created this revision.
pcc added reviewers: peter.smith, grimar, ruiu.
Herald added subscribers: arichardson, emaste.
Herald added a reviewer: espindola.

Non-GOT non-PLT relocations to non-preemptible ifuncs result in the
creation of a canonical PLT, which now takes the identity of the IFUNC
in the symbol table. This (a) ensures address consistency inside and
outside the module, and (b) fixes a bug where some of these relocations
end up pointing to the resolver.

Fixes (at least) PR40474 and PR40501.

TODO:

- Fix tests.
- Maybe look at some of the FIXMEs. The one about turning absolute relocations into IRELATIVEs would avoid an indirection in common cases and match bfd/gold's behaviour for the repro in PR40501.


Repository:
  rL LLVM

https://reviews.llvm.org/D57371

Files:
  lld/ELF/InputSection.cpp
  lld/ELF/Relocations.cpp
  lld/ELF/Relocations.h
  lld/ELF/Symbols.cpp

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