From 4cd07dbeec9811a98efbc0ed3518e78dc38c0f53 Mon Sep 17 00:00:00 2001 From: Serge Guelton Date: Wed, 5 Jun 2019 06:35:10 +0000 Subject: [PATCH] Reduce memory consumption of coverage dumps Avoiding an intermediate join operation removes the need for an intermediate buffer that may be quite large, as showcased by https://bugs.llvm.org/show_bug.cgi?id=41965 Differential Revision: https://reviews.llvm.org/D62623 llvm-svn: 362584 --- clang/lib/CodeGen/CoverageMappingGen.cpp | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/clang/lib/CodeGen/CoverageMappingGen.cpp b/clang/lib/CodeGen/CoverageMappingGen.cpp index ad014b5..d900c7b 100644 --- a/clang/lib/CodeGen/CoverageMappingGen.cpp +++ b/clang/lib/CodeGen/CoverageMappingGen.cpp @@ -1388,10 +1388,19 @@ void CoverageMappingModuleGen::emit() { std::string FilenamesAndCoverageMappings; llvm::raw_string_ostream OS(FilenamesAndCoverageMappings); CoverageFilenamesSectionWriter(FilenameRefs).write(OS); - std::string RawCoverageMappings = - llvm::join(CoverageMappings.begin(), CoverageMappings.end(), ""); - OS << RawCoverageMappings; - size_t CoverageMappingSize = RawCoverageMappings.size(); + + // Stream the content of CoverageMappings to OS while keeping + // memory consumption under control. + size_t CoverageMappingSize = 0; + for (auto &S : CoverageMappings) { + CoverageMappingSize += S.size(); + OS << S; + S.clear(); + S.shrink_to_fit(); + } + CoverageMappings.clear(); + CoverageMappings.shrink_to_fit(); + size_t FilenamesSize = OS.str().size() - CoverageMappingSize; // Append extra zeroes if necessary to ensure that the size of the filenames // and coverage mappings is a multiple of 8. -- 2.7.4