Author: Sam McCall Date: 2022-10-05T23:02:28+02:00 New Revision: 60b4b39f5a78661e2b9d222cf6ba7d9d5d7511ed
URL: https://github.com/llvm/llvm-project/commit/60b4b39f5a78661e2b9d222cf6ba7d9d5d7511ed DIFF: https://github.com/llvm/llvm-project/commit/60b4b39f5a78661e2b9d222cf6ba7d9d5d7511ed.diff LOG: [clangd] Avoid lexicographic compare when sorting SymbolIDs. NFC These are 8 bytes and we don't care about the actual ordering, so use integer compare. The array generated code has some extra byte swaps (clang), calls memcmp (gcc) or inlines a big chain of comparisons (MSVC): https://godbolt.org/z/e79r6jM6K Added: Modified: clang-tools-extra/clangd/index/SymbolID.h Removed: ################################################################################ diff --git a/clang-tools-extra/clangd/index/SymbolID.h b/clang-tools-extra/clangd/index/SymbolID.h index d1512080edbfb..e8aa462e96c17 100644 --- a/clang-tools-extra/clangd/index/SymbolID.h +++ b/clang-tools-extra/clangd/index/SymbolID.h @@ -39,7 +39,9 @@ class SymbolID { } bool operator!=(const SymbolID &Sym) const { return !(*this == Sym); } bool operator<(const SymbolID &Sym) const { - return HashValue < Sym.HashValue; + // Avoid lexicographic compare which requires swapping bytes or even memcmp! + return llvm::bit_cast<IntTy>(HashValue) < + llvm::bit_cast<IntTy>(Sym.HashValue); } // The stored hash is truncated to RawSize bytes. @@ -56,6 +58,8 @@ class SymbolID { explicit operator bool() const { return !isNull(); } private: + using IntTy = uint64_t; + static_assert(sizeof(IntTy) == RawSize); std::array<uint8_t, RawSize> HashValue{}; }; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
