Author: Jan Svoboda Date: 2023-05-10T10:41:33-07:00 New Revision: 63eb04a3683996db26dbf1534682c5696d93b080
URL: https://github.com/llvm/llvm-project/commit/63eb04a3683996db26dbf1534682c5696d93b080 DIFF: https://github.com/llvm/llvm-project/commit/63eb04a3683996db26dbf1534682c5696d93b080.diff LOG: [clang][modules] Avoid unnecessary writes of .timestamp files Clang currently updates the mtime of .timestamp files on each load of the corresponding .pcm file. This is not necessary. In a given build session, Clang only needs to write the .timestamp file once, when we first validate the input files. This patch makes it so that we only touch the .timestamp file when it's older than the build session, alleviating some filesystem contention in clang-scan-deps. Reviewed By: benlangmuir Differential Revision: https://reviews.llvm.org/D149802 Added: Modified: clang/lib/Serialization/ASTReader.cpp Removed: ################################################################################ diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp index 9c31f9db14679..bdf476cf128a3 100644 --- a/clang/lib/Serialization/ASTReader.cpp +++ b/clang/lib/Serialization/ASTReader.cpp @@ -4507,18 +4507,16 @@ ASTReader::ASTReadResult ASTReader::ReadAST(StringRef FileName, } } - if (PP.getHeaderSearchInfo() - .getHeaderSearchOpts() - .ModulesValidateOncePerBuildSession) { + HeaderSearchOptions &HSOpts = PP.getHeaderSearchInfo().getHeaderSearchOpts(); + if (HSOpts.ModulesValidateOncePerBuildSession) { // Now we are certain that the module and all modules it depends on are - // up to date. Create or update timestamp files for modules that are - // located in the module cache (not for PCH files that could be anywhere - // in the filesystem). + // up-to-date. For implicitly-built module files, ensure the corresponding + // timestamp files are up-to-date in this build session. for (unsigned I = 0, N = Loaded.size(); I != N; ++I) { ImportedModule &M = Loaded[I]; - if (M.Mod->Kind == MK_ImplicitModule) { + if (M.Mod->Kind == MK_ImplicitModule && + M.Mod->InputFilesValidationTimestamp < HSOpts.BuildSessionTimestamp) updateModuleTimestamp(*M.Mod); - } } } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
