[PATCH] D155781: [Support] Change StringMap hash function from xxHash64 to xxh3_64bits

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added reviewers: dblaikie, erikdesjardins, JDevlieghere, lhames, serge-sans-paille.
Herald added subscribers: mgrang, hiraditya, kristof.beyls.
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MaskRay requested review of this revision.
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Similar to D142862 <https://reviews.llvm.org/D142862>.

xxh3 is significantly faster than xxh64. Switch to xxh3, as we did for
for lld and llvm-dwarfutil to increase performance (D154813 <https://reviews.llvm.org/D154813> D155675 <https://reviews.llvm.org/D155675>).
While I think StringMap is not a bottleneck for most applications, it
seems good to eliminate the slower xxh64. In addition, according to
D142862 <https://reviews.llvm.org/D142862>, Rust with a large constant string is sensitive to the StringMap
performance.

I have fixed all found issues separately, but two are remaining:

- ExecutionEngine/RuntimeDyld/ARM/MachO_ARM_PIC_relocations.s has a failure due to StringMap iteration order. I think it's a lurking issue in the code but likely usually benign. Perhaps @lhames can take a look?
- lib/ExecutionEngine/Orc/DebugUtils.cpp: adjust 3fcd3669e3dc7c5ba72d3bfceef42b2f833254ec <https://reviews.llvm.org/rG3fcd3669e3dc7c5ba72d3bfceef42b2f833254ec>. This part should be committed separately.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D155781

Files:
  llvm/lib/ExecutionEngine/Orc/DebugUtils.cpp
  llvm/lib/Support/StringMap.cpp
  llvm/test/DebugInfo/X86/gnu-public-names-gmlt.ll
  llvm/test/DebugInfo/X86/gnu-public-names.ll
  llvm/test/ExecutionEngine/RuntimeDyld/ARM/MachO_ARM_PIC_relocations.s

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