Hi Richard, This commit looks like it caused a regression in PCH-loading performance when the PCH imports modules. It doesn’t affect performance of loading modules on their own, or of a PCH that doesn’t use modules. If you have access to a Darwin system, it’s easy to reproduce with:
$ cat t.h @import Cocoa; $ cat t.m // empty $ clang -fmodules -fmodules-cache-path=mcp -x objective-c-header t.h -o t.pch $ time clang -fmodules -fmodules-cache-path=mcp -Xclang -include-pch -Xclang t.pch t.m -fsyntax-only I’m seeing ~8x difference between r228233 and r228234. In real world code (where the .m file isn’t empty) we’ve seen up to a ~90% difference. Do you know what’s going on here? When a PCH loads I think we do it without Sema, but (at least previously) queued up the interesting Decls we saw for when Sema was added later. So I’m surprised this had such a big effect. Ben > On Feb 4, 2015, at 3:37 PM, Richard Smith <[email protected]> wrote: > > Author: rsmith > Date: Wed Feb 4 17:37:59 2015 > New Revision: 228234 > > URL: http://llvm.org/viewvc/llvm-project?rev=228234&view=rev > Log: > [modules] When using -E, we may try to merge decls despite having no Sema > object. In such a case, use the TU's DC for merging global decls rather than > giving up when we find there is no TU scope. > > Ultimately, we should probably avoid all loading of decls when preprocessing, > but there are other reasonable use cases for loading an AST file with no Sema > object for which this is the right thing. > > Added: > cfe/trunk/test/Modules/Inputs/preprocess/ > cfe/trunk/test/Modules/Inputs/preprocess/file.h > cfe/trunk/test/Modules/Inputs/preprocess/fwd.h > cfe/trunk/test/Modules/Inputs/preprocess/module.modulemap > Modified: > cfe/trunk/include/clang/Frontend/CompilerInstance.h > cfe/trunk/lib/Frontend/CompilerInstance.cpp > cfe/trunk/lib/Serialization/ASTReaderDecl.cpp > cfe/trunk/test/Modules/preprocess.m > > Modified: cfe/trunk/include/clang/Frontend/CompilerInstance.h > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Frontend/CompilerInstance.h?rev=228234&r1=228233&r2=228234&view=diff > ============================================================================== > --- cfe/trunk/include/clang/Frontend/CompilerInstance.h (original) > +++ cfe/trunk/include/clang/Frontend/CompilerInstance.h Wed Feb 4 17:37:59 > 2015 > @@ -588,7 +588,7 @@ public: > /// Create an external AST source to read a PCH file. > /// > /// \return - The new object on success, or null on failure. > - static ExternalASTSource *createPCHExternalASTSource( > + static IntrusiveRefCntPtr<ASTReader> createPCHExternalASTSource( > StringRef Path, const std::string &Sysroot, bool DisablePCHValidation, > bool AllowPCHWithCompilerErrors, Preprocessor &PP, ASTContext &Context, > void *DeserializationListener, bool OwnDeserializationListener, > > Modified: cfe/trunk/lib/Frontend/CompilerInstance.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInstance.cpp?rev=228234&r1=228233&r2=228234&view=diff > ============================================================================== > --- cfe/trunk/lib/Frontend/CompilerInstance.cpp (original) > +++ cfe/trunk/lib/Frontend/CompilerInstance.cpp Wed Feb 4 17:37:59 2015 > @@ -388,32 +388,30 @@ void CompilerInstance::createASTContext( > void CompilerInstance::createPCHExternalASTSource( > StringRef Path, bool DisablePCHValidation, bool > AllowPCHWithCompilerErrors, > void *DeserializationListener, bool OwnDeserializationListener) { > - IntrusiveRefCntPtr<ExternalASTSource> Source; > bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0; > - Source = createPCHExternalASTSource( > + ModuleManager = createPCHExternalASTSource( > Path, getHeaderSearchOpts().Sysroot, DisablePCHValidation, > AllowPCHWithCompilerErrors, getPreprocessor(), getASTContext(), > DeserializationListener, OwnDeserializationListener, Preamble, > getFrontendOpts().UseGlobalModuleIndex); > - ModuleManager = static_cast<ASTReader*>(Source.get()); > - getASTContext().setExternalSource(Source); > } > > -ExternalASTSource *CompilerInstance::createPCHExternalASTSource( > +IntrusiveRefCntPtr<ASTReader> CompilerInstance::createPCHExternalASTSource( > StringRef Path, const std::string &Sysroot, bool DisablePCHValidation, > bool AllowPCHWithCompilerErrors, Preprocessor &PP, ASTContext &Context, > void *DeserializationListener, bool OwnDeserializationListener, > bool Preamble, bool UseGlobalModuleIndex) { > HeaderSearchOptions &HSOpts = > PP.getHeaderSearchInfo().getHeaderSearchOpts(); > > - std::unique_ptr<ASTReader> Reader; > - Reader.reset(new ASTReader(PP, Context, > - Sysroot.empty() ? "" : Sysroot.c_str(), > - DisablePCHValidation, > - AllowPCHWithCompilerErrors, > - /*AllowConfigurationMismatch*/false, > - HSOpts.ModulesValidateSystemHeaders, > - UseGlobalModuleIndex)); > + IntrusiveRefCntPtr<ASTReader> Reader( > + new ASTReader(PP, Context, Sysroot.empty() ? "" : Sysroot.c_str(), > + DisablePCHValidation, AllowPCHWithCompilerErrors, > + /*AllowConfigurationMismatch*/ false, > + HSOpts.ModulesValidateSystemHeaders, > UseGlobalModuleIndex)); > + > + // We need the external source to be set up before we read the AST, because > + // eagerly-deserialized declarations may use it. > + Context.setExternalSource(Reader.get()); > > Reader->setDeserializationListener( > static_cast<ASTDeserializationListener *>(DeserializationListener), > @@ -427,7 +425,7 @@ ExternalASTSource *CompilerInstance::cre > // Set the predefines buffer as suggested by the PCH reader. Typically, > the > // predefines buffer will be empty. > PP.setPredefines(Reader->getSuggestedPredefines()); > - return Reader.release(); > + return Reader; > > case ASTReader::Failure: > // Unrecoverable failure: don't even try to process the input file. > @@ -442,6 +440,7 @@ ExternalASTSource *CompilerInstance::cre > break; > } > > + Context.setExternalSource(nullptr); > return nullptr; > } > > > Modified: cfe/trunk/lib/Serialization/ASTReaderDecl.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTReaderDecl.cpp?rev=228234&r1=228233&r2=228234&view=diff > ============================================================================== > --- cfe/trunk/lib/Serialization/ASTReaderDecl.cpp (original) > +++ cfe/trunk/lib/Serialization/ASTReaderDecl.cpp Wed Feb 4 17:37:59 2015 > @@ -2591,6 +2591,11 @@ DeclContext *ASTDeclReader::getPrimaryCo > return ED->getASTContext().getLangOpts().CPlusPlus? ED->getDefinition() > : nullptr; > > + // We can see the TU here only if we have no Sema object. In that case, > + // there's no TU scope to look in, so using the DC alone is sufficient. > + if (auto *TU = dyn_cast<TranslationUnitDecl>(DC)) > + return TU; > + > return nullptr; > } > > > Added: cfe/trunk/test/Modules/Inputs/preprocess/file.h > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/preprocess/file.h?rev=228234&view=auto > ============================================================================== > --- cfe/trunk/test/Modules/Inputs/preprocess/file.h (added) > +++ cfe/trunk/test/Modules/Inputs/preprocess/file.h Wed Feb 4 17:37:59 2015 > @@ -0,0 +1,3 @@ > +struct __FILE; > +#include "fwd.h" > +typedef struct __FILE FILE; > > Added: cfe/trunk/test/Modules/Inputs/preprocess/fwd.h > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/preprocess/fwd.h?rev=228234&view=auto > ============================================================================== > --- cfe/trunk/test/Modules/Inputs/preprocess/fwd.h (added) > +++ cfe/trunk/test/Modules/Inputs/preprocess/fwd.h Wed Feb 4 17:37:59 2015 > @@ -0,0 +1 @@ > +struct __FILE; > > Added: cfe/trunk/test/Modules/Inputs/preprocess/module.modulemap > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/preprocess/module.modulemap?rev=228234&view=auto > ============================================================================== > --- cfe/trunk/test/Modules/Inputs/preprocess/module.modulemap (added) > +++ cfe/trunk/test/Modules/Inputs/preprocess/module.modulemap Wed Feb 4 > 17:37:59 2015 > @@ -0,0 +1,2 @@ > +module fwd { header "fwd.h" export * } > +module file { header "file.h" export * } > > Modified: cfe/trunk/test/Modules/preprocess.m > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/preprocess.m?rev=228234&r1=228233&r2=228234&view=diff > ============================================================================== > --- cfe/trunk/test/Modules/preprocess.m (original) > +++ cfe/trunk/test/Modules/preprocess.m Wed Feb 4 17:37:59 2015 > @@ -1,9 +1,14 @@ > // RUN: rm -rf %t > -// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I %S/Inputs -include > %S/Inputs/preprocess-prefix.h -E %s | FileCheck -strict-whitespace %s > -// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I %S/Inputs -x > objective-c-header -emit-pch %S/Inputs/preprocess-prefix.h -o %t.pch > -// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I %S/Inputs > -include-pch %t.pch -E %s | FileCheck -strict-whitespace %s > +// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I %S/Inputs -I > %S/Inputs/preprocess -include %S/Inputs/preprocess-prefix.h -E %s | FileCheck > -strict-whitespace %s > +// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I %S/Inputs -I > %S/Inputs/preprocess -x objective-c-header -emit-pch > %S/Inputs/preprocess-prefix.h -o %t.pch > +// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I %S/Inputs -I > %S/Inputs/preprocess -include-pch %t.pch -E %s | FileCheck -strict-whitespace > %s > +// > +// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I %S/Inputs -I > %S/Inputs/preprocess -x objective-c++ -include %S/Inputs/preprocess-prefix.h > -E %s | FileCheck -strict-whitespace %s > +// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I %S/Inputs -I > %S/Inputs/preprocess -x objective-c++-header -emit-pch > %S/Inputs/preprocess-prefix.h -o %t.pch > +// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -I %S/Inputs -I > %S/Inputs/preprocess -x objective-c++ -include-pch %t.pch -E %s | FileCheck > -strict-whitespace %s > #import "diamond_right.h" > #import "diamond_right.h" // to check that imports get their own line > +#include "file.h" > void test() { > top_left_before(); > left_and_right(); > @@ -15,6 +20,7 @@ void test() { > > // CHECK: @import diamond_right; /* clang -E: implicit import for > "{{.*}}diamond_right.h" */{{$}} > // CHECK: @import diamond_right; /* clang -E: implicit import for > "{{.*}}diamond_right.h" */{{$}} > +// CHECK: @import file; /* clang -E: implicit import for "{{.*}}file.h" > */{{$}} > // CHECK-NEXT: void test() {{{$}} > // CHECK-NEXT: top_left_before();{{$}} > // CHECK-NEXT: left_and_right();{{$}} > > > _______________________________________________ > cfe-commits mailing list > [email protected] > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
