Author: Jaroslav Sevcik Date: 2020-01-22T15:20:06+01:00 New Revision: 4481eefbe8425c63289186dd13319aaa7043e67f
URL: https://github.com/llvm/llvm-project/commit/4481eefbe8425c63289186dd13319aaa7043e67f DIFF: https://github.com/llvm/llvm-project/commit/4481eefbe8425c63289186dd13319aaa7043e67f.diff LOG: [ASTImporter] Properly delete decls from SavedImportPaths Summary: We see a significant regression (~40% slower on large codebases) in expression evaluation after https://reviews.llvm.org/rL364771. A sampling profile shows the extra time is spent in SavedImportPathsTy::operator[] when called from ASTImporter::Import. I believe this is because ASTImporter::Import adds an element to the SavedImportPaths map for each decl unconditionally (see https://github.com/llvm/llvm-project/blob/7b81c3f8793d30a4285095a9b67dcfca2117916c/clang/lib/AST/ASTImporter.cpp#L8256). To fix this, we call SavedImportPathsTy::erase on the declaration rather than clearing its value vector. That way we do not accidentally introduce new empty elements. (With this patch the performance is restored, and we do not see SavedImportPathsTy::operator[] in the profile anymore.) Reviewers: martong, teemperor, a.sidorin, shafik Reviewed By: martong Subscribers: rnkovacs, cfe-commits Tags: #clang Differential Revision: https://reviews.llvm.org/D73166 Added: Modified: clang/lib/AST/ASTImporter.cpp Removed: ################################################################################ diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp index 1f2ce30398c9..9dd20e2d5921 100644 --- a/clang/lib/AST/ASTImporter.cpp +++ b/clang/lib/AST/ASTImporter.cpp @@ -8253,7 +8253,7 @@ Expected<Decl *> ASTImporter::Import(Decl *FromD) { // FIXME Should we remove these Decls from the LookupTable, // and from ImportedFromDecls? } - SavedImportPaths[FromD].clear(); + SavedImportPaths.erase(FromD); // Do not return ToDOrErr, error was taken out of it. return make_error<ImportError>(ErrOut); @@ -8286,7 +8286,7 @@ Expected<Decl *> ASTImporter::Import(Decl *FromD) { Imported(FromD, ToD); updateFlags(FromD, ToD); - SavedImportPaths[FromD].clear(); + SavedImportPaths.erase(FromD); return ToDOrErr; } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
