[PATCH] D46755: [LLD][ELF] Implement --keep-unique option

[Peter Smith via Phabricator via llvm-commits]

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

The --keep-unique <symbol> option is taken from gold. The intention is that <symbol> will be prevented from being folded by ICF. Although not specifically mentioned in the documentation <symbol> only matches global symbols. In gold the option "unfolds" sections that have been folded due to ICF. For LLD I've decided to make sections defining a global symbol specified by --keep-unique inelligible for ICF.

This option is used within the Android ART runtime for __jit_debug_register_code and __dex_debug_register_code. Supporting it will allow ART to be linked with LLD. I think it could also be used as a basis for --icf=safe (find unsafe symbols and exclude the sections that define them).


https://reviews.llvm.org/D46755

Files:
  ELF/Config.h
  ELF/Driver.cpp
  ELF/ICF.cpp
  ELF/Options.td
  test/ELF/icf-keep-unique.s

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