llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-mc Author: Amir Ayupov (aaupov) <details> <summary>Changes</summary> Add `IsMMapped` flag to `buildGUID2FuncDescMap` controlling whether to allocate a string in `FuncNameAllocator` or use StringRef directly. This saves ~0.7 GiB peak RSS in perf2bolt processing a medium sized binary with ~0.8 GiB .pseudo_probe_desc section. This is because BOLT keeps file sections in memory while processing them whereas llvm-profgen constructs GUID2FuncDescMap and then releases the binary. Test Plan: no-op for llvm-profgen, NFC for perf2bolt --- Full diff: https://github.com/llvm/llvm-project/pull/112996.diff 3 Files Affected: - (modified) bolt/lib/Rewrite/PseudoProbeRewriter.cpp (+1-1) - (modified) llvm/include/llvm/MC/MCPseudoProbe.h (+4-1) - (modified) llvm/lib/MC/MCPseudoProbe.cpp (+4-2) ``````````diff diff --git a/bolt/lib/Rewrite/PseudoProbeRewriter.cpp b/bolt/lib/Rewrite/PseudoProbeRewriter.cpp index 8647df4b0edf82..4fecfe8c3c09b1 100644 --- a/bolt/lib/Rewrite/PseudoProbeRewriter.cpp +++ b/bolt/lib/Rewrite/PseudoProbeRewriter.cpp @@ -128,7 +128,7 @@ void PseudoProbeRewriter::parsePseudoProbe(bool ProfiledOnly) { StringRef Contents = PseudoProbeDescSection->getContents(); if (!ProbeDecoder.buildGUID2FuncDescMap( reinterpret_cast<const uint8_t *>(Contents.data()), - Contents.size())) { + Contents.size(), /*IsMMapped*/true)) { errs() << "BOLT-WARNING: fail in building GUID2FuncDescMap\n"; return; } diff --git a/llvm/include/llvm/MC/MCPseudoProbe.h b/llvm/include/llvm/MC/MCPseudoProbe.h index 4bfae9eba1a0aa..fd1f0557895446 100644 --- a/llvm/include/llvm/MC/MCPseudoProbe.h +++ b/llvm/include/llvm/MC/MCPseudoProbe.h @@ -431,7 +431,10 @@ class MCPseudoProbeDecoder { using Uint64Map = DenseMap<uint64_t, uint64_t>; // Decode pseudo_probe_desc section to build GUID to PseudoProbeFuncDesc map. - bool buildGUID2FuncDescMap(const uint8_t *Start, std::size_t Size); + // If pseudo_probe_desc section is mapped to memory and \p IsMMapped is true, + // uses StringRefs pointing to the section. + bool buildGUID2FuncDescMap(const uint8_t *Start, std::size_t Size, + bool IsMMapped = false); // Decode pseudo_probe section to count the number of probes and inlined // function records for each function record. diff --git a/llvm/lib/MC/MCPseudoProbe.cpp b/llvm/lib/MC/MCPseudoProbe.cpp index 90d7588407068a..2a3761b2cfe718 100644 --- a/llvm/lib/MC/MCPseudoProbe.cpp +++ b/llvm/lib/MC/MCPseudoProbe.cpp @@ -375,7 +375,8 @@ ErrorOr<StringRef> MCPseudoProbeDecoder::readString(uint32_t Size) { } bool MCPseudoProbeDecoder::buildGUID2FuncDescMap(const uint8_t *Start, - std::size_t Size) { + std::size_t Size, + bool IsMMapped) { // The pseudo_probe_desc section has a format like: // .section .pseudo_probe_desc,"",@progbits // .quad -5182264717993193164 // GUID @@ -422,7 +423,8 @@ bool MCPseudoProbeDecoder::buildGUID2FuncDescMap(const uint8_t *Start, StringRef Name = cantFail(errorOrToExpected(readString(NameSize))); // Initialize PseudoProbeFuncDesc and populate it into GUID2FuncDescMap - GUID2FuncDescMap.emplace_back(GUID, Hash, Name.copy(FuncNameAllocator)); + GUID2FuncDescMap.emplace_back( + GUID, Hash, IsMMapped ? Name : Name.copy(FuncNameAllocator)); } assert(Data == End && "Have unprocessed data in pseudo_probe_desc section"); assert(GUID2FuncDescMap.size() == FuncDescCount && `````````` </details> https://github.com/llvm/llvm-project/pull/112996 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
