Author: vsapsai Date: Wed Mar 21 14:28:54 2018 New Revision: 328153 URL: http://llvm.org/viewvc/llvm-project?rev=328153&view=rev Log: [Modules] Fix creating fake definition data for lambdas.
During reading C++ definition data for lambda we can access CXXRecordDecl representing lambda before we finished reading the definition data. This can happen by reading a captured variable which is VarDecl, then reading its decl context which is CXXMethodDecl `operator()`, then trying to merge redeclarable methods and accessing enclosing CXXRecordDecl. The call stack looks roughly like VisitCXXRecordDecl ReadCXXRecordDefinition VisitVarDecl VisitCXXMethodDecl mergeRedeclarable getPrimaryContextForMerging If we add fake definition data at this point, later we'll hit the assertion Assertion failed: (!DD.IsLambda && !MergeDD.IsLambda && "faked up lambda definition?"), function MergeDefinitionData, file clang/lib/Serialization/ASTReaderDecl.cpp, line 1675. The fix is to assign definition data before reading it. Fixes PR32556. rdar://problem/37461072 Reviewers: rsmith, bruno Reviewed By: rsmith Subscribers: cfe-commits, jkorous-apple, aprantl Differential Revision: https://reviews.llvm.org/D43494 Added: cfe/trunk/test/Modules/Inputs/self-referencing-lambda/ cfe/trunk/test/Modules/Inputs/self-referencing-lambda/a.h cfe/trunk/test/Modules/Inputs/self-referencing-lambda/module.modulemap cfe/trunk/test/Modules/self-referencing-lambda.cpp Modified: cfe/trunk/lib/Serialization/ASTReaderDecl.cpp Modified: cfe/trunk/lib/Serialization/ASTReaderDecl.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTReaderDecl.cpp?rev=328153&r1=328152&r2=328153&view=diff ============================================================================== --- cfe/trunk/lib/Serialization/ASTReaderDecl.cpp (original) +++ cfe/trunk/lib/Serialization/ASTReaderDecl.cpp Wed Mar 21 14:28:54 2018 @@ -1784,29 +1784,31 @@ void ASTDeclReader::ReadCXXRecordDefinit else DD = new (C) struct CXXRecordDecl::DefinitionData(D); + CXXRecordDecl *Canon = D->getCanonicalDecl(); + // Set decl definition data before reading it, so that during deserialization + // when we read CXXRecordDecl, it already has definition data and we don't + // set fake one. + if (!Canon->DefinitionData) + Canon->DefinitionData = DD; + D->DefinitionData = Canon->DefinitionData; ReadCXXDefinitionData(*DD, D); - // We might already have a definition for this record. This can happen either - // because we're reading an update record, or because we've already done some - // merging. Either way, just merge into it. - CXXRecordDecl *Canon = D->getCanonicalDecl(); - if (Canon->DefinitionData) { + // We might already have a different definition for this record. This can + // happen either because we're reading an update record, or because we've + // already done some merging. Either way, just merge into it. + if (Canon->DefinitionData != DD) { MergeDefinitionData(Canon, std::move(*DD)); - D->DefinitionData = Canon->DefinitionData; return; } // Mark this declaration as being a definition. D->IsCompleteDefinition = true; - D->DefinitionData = DD; // If this is not the first declaration or is an update record, we can have // other redeclarations already. Make a note that we need to propagate the // DefinitionData pointer onto them. - if (Update || Canon != D) { - Canon->DefinitionData = D->DefinitionData; + if (Update || Canon != D) Reader.PendingDefinitions.insert(D); - } } ASTDeclReader::RedeclarableResult Added: cfe/trunk/test/Modules/Inputs/self-referencing-lambda/a.h URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/self-referencing-lambda/a.h?rev=328153&view=auto ============================================================================== --- cfe/trunk/test/Modules/Inputs/self-referencing-lambda/a.h (added) +++ cfe/trunk/test/Modules/Inputs/self-referencing-lambda/a.h Wed Mar 21 14:28:54 2018 @@ -0,0 +1,4 @@ +void f() { + int x = 0; + auto q = [xm = x]{}; +} Added: cfe/trunk/test/Modules/Inputs/self-referencing-lambda/module.modulemap URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/self-referencing-lambda/module.modulemap?rev=328153&view=auto ============================================================================== --- cfe/trunk/test/Modules/Inputs/self-referencing-lambda/module.modulemap (added) +++ cfe/trunk/test/Modules/Inputs/self-referencing-lambda/module.modulemap Wed Mar 21 14:28:54 2018 @@ -0,0 +1,4 @@ +module "a.h" { + header "a.h" + export * +} Added: cfe/trunk/test/Modules/self-referencing-lambda.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/self-referencing-lambda.cpp?rev=328153&view=auto ============================================================================== --- cfe/trunk/test/Modules/self-referencing-lambda.cpp (added) +++ cfe/trunk/test/Modules/self-referencing-lambda.cpp Wed Mar 21 14:28:54 2018 @@ -0,0 +1,5 @@ +// RUN: rm -rf %t +// RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -I %S/Inputs/self-referencing-lambda %s -verify -emit-obj -o %t2.o +// expected-no-diagnostics + +#include "a.h" _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits