Author: ibiryukov Date: Fri Nov 24 05:12:38 2017 New Revision: 318945 URL: http://llvm.org/viewvc/llvm-project?rev=318945&view=rev Log: Avoid copying the data of in-memory preambles
Summary: Preambles are large and we should avoid copying them. Reviewers: bkramer, klimek Reviewed By: bkramer Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D40302 Modified: cfe/trunk/include/clang/Frontend/PrecompiledPreamble.h cfe/trunk/lib/Frontend/PrecompiledPreamble.cpp Modified: cfe/trunk/include/clang/Frontend/PrecompiledPreamble.h URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Frontend/PrecompiledPreamble.h?rev=318945&r1=318944&r2=318945&view=diff ============================================================================== --- cfe/trunk/include/clang/Frontend/PrecompiledPreamble.h (original) +++ cfe/trunk/include/clang/Frontend/PrecompiledPreamble.h Fri Nov 24 05:12:38 2017 @@ -98,6 +98,10 @@ public: /// Changes options inside \p CI to use PCH from this preamble. Also remaps /// main file to \p MainFileBuffer and updates \p VFS to ensure the preamble /// is accessible. + /// For in-memory preambles, PrecompiledPreamble instance continues to own + /// the MemoryBuffer with the Preamble after this method returns. The caller + /// is reponsible for making sure the PrecompiledPreamble instance outlives + /// the compiler run and the AST that will be using the PCH. void AddImplicitPreamble(CompilerInvocation &CI, IntrusiveRefCntPtr<vfs::FileSystem> &VFS, llvm::MemoryBuffer *MainFileBuffer) const; Modified: cfe/trunk/lib/Frontend/PrecompiledPreamble.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/PrecompiledPreamble.cpp?rev=318945&r1=318944&r2=318945&view=diff ============================================================================== --- cfe/trunk/lib/Frontend/PrecompiledPreamble.cpp (original) +++ cfe/trunk/lib/Frontend/PrecompiledPreamble.cpp Fri Nov 24 05:12:38 2017 @@ -699,9 +699,7 @@ void PrecompiledPreamble::setupPreambleS StringRef PCHPath = getInMemoryPreamblePath(); PreprocessorOpts.ImplicitPCHInclude = PCHPath; - // FIMXE(ibiryukov): Preambles can be large. We should allow shared access - // to the preamble data instead of copying it here. - auto Buf = llvm::MemoryBuffer::getMemBufferCopy(Storage.asMemory().Data); + auto Buf = llvm::MemoryBuffer::getMemBuffer(Storage.asMemory().Data); VFS = createVFSOverlayForPreamblePCH(PCHPath, std::move(Buf), VFS); } } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits