[PATCH] D98762: [LTO][MC] Discard non-prevailing defined symbols in module-level assembly

[Yuanfang Chen via Phabricator via llvm-commits]

ychen created this revision.
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This is the alternative approach to D96931 <https://reviews.llvm.org/D96931>.

In LTO, for each module with inlineasm block, prepend directive ".module" and
(optioanlly) ".lto_discard <sym>, <sym>*" to the beginning of the inline
asm.

In MC while emitting for inline asm, discard symbol binding & symbol
definitions according to ".lto_disard".

PS: ".lto_discard" is not strictly required but it would the MC change
much simpler. I didn't add any standalone MC tests because the only
client for these two directives should be LTO.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D98762

Files:
  llvm/include/llvm/MC/MCContext.h
  llvm/include/llvm/MC/MCParser/MCAsmParser.h
  llvm/lib/LTO/LTO.cpp
  llvm/lib/MC/MCParser/AsmParser.cpp
  llvm/lib/MC/MCParser/ELFAsmParser.cpp
  llvm/test/LTO/X86/weak-asm.ll

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