Author: sepavloff Date: Wed Jun 14 05:07:02 2017 New Revision: 305379 URL: http://llvm.org/viewvc/llvm-project?rev=305379&view=rev Log: Function with unparsed body is a definition
While a function body is being parsed, the function declaration is not considered as a definition because it does not have a body yet. In some cases it leads to incorrect interpretation, the case is presented in https://bugs.llvm.org/show_bug.cgi?id=14785: ``` template<typename T> struct Somewhat { void internal() const {} friend void operator+(int const &, Somewhat<T> const &) {} }; void operator+(int const &, Somewhat<char> const &x) { x.internal(); } ``` When statement `x.internal()` in the body of global `operator+` is parsed, the type of `x` must be completed, so the instantiation of `Somewhat<char>` is started. It instantiates the declaration of `operator+` defined inline, and makes a check for redefinition. The check does not detect another definition because the declaration of `operator+` is still not defining as does not have a body yet. To solves this problem the function `isThisDeclarationADefinition` considers a function declaration as a definition if it has flag `WillHaveBody` set. This change fixes PR14785. Differential Revision: https://reviews.llvm.org/D30375 Modified: cfe/trunk/include/clang/AST/Decl.h cfe/trunk/lib/Sema/SemaCUDA.cpp cfe/trunk/lib/Sema/SemaDecl.cpp cfe/trunk/lib/Sema/SemaDeclCXX.cpp cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp cfe/trunk/test/SemaCXX/friend2.cpp Modified: cfe/trunk/include/clang/AST/Decl.h URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Decl.h?rev=305379&r1=305378&r2=305379&view=diff ============================================================================== --- cfe/trunk/include/clang/AST/Decl.h (original) +++ cfe/trunk/include/clang/AST/Decl.h Wed Jun 14 05:07:02 2017 @@ -1872,7 +1872,7 @@ public: /// bool isThisDeclarationADefinition() const { return IsDeleted || IsDefaulted || Body || IsLateTemplateParsed || - hasDefiningAttr(); + WillHaveBody || hasDefiningAttr(); } /// doesThisDeclarationHaveABody - Returns whether this specific Modified: cfe/trunk/lib/Sema/SemaCUDA.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaCUDA.cpp?rev=305379&r1=305378&r2=305379&view=diff ============================================================================== --- cfe/trunk/lib/Sema/SemaCUDA.cpp (original) +++ cfe/trunk/lib/Sema/SemaCUDA.cpp Wed Jun 14 05:07:02 2017 @@ -629,12 +629,6 @@ static bool IsKnownEmitted(Sema &S, Func // emitted, because (say) the definition could include "inline". FunctionDecl *Def = FD->getDefinition(); - // We may currently be parsing the body of FD, in which case - // FD->getDefinition() will be null, but we still want to treat FD as though - // it's a definition. - if (!Def && FD->willHaveBody()) - Def = FD; - if (Def && !isDiscardableGVALinkage(S.getASTContext().GetGVALinkageForFunction(Def))) return true; Modified: cfe/trunk/lib/Sema/SemaDecl.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=305379&r1=305378&r2=305379&view=diff ============================================================================== --- cfe/trunk/lib/Sema/SemaDecl.cpp (original) +++ cfe/trunk/lib/Sema/SemaDecl.cpp Wed Jun 14 05:07:02 2017 @@ -12218,6 +12218,7 @@ Decl *Sema::ActOnFinishFunctionBody(Decl if (FD) { FD->setBody(Body); + FD->setWillHaveBody(false); if (getLangOpts().CPlusPlus14) { if (!FD->isInvalidDecl() && Body && !FD->isDependentContext() && Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=305379&r1=305378&r2=305379&view=diff ============================================================================== --- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original) +++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Wed Jun 14 05:07:02 2017 @@ -13878,6 +13878,9 @@ void Sema::SetDeclDeleted(Decl *Dcl, Sou return; } + // Deleted function does not have a body. + Fn->setWillHaveBody(false); + if (const FunctionDecl *Prev = Fn->getPreviousDecl()) { // Don't consider the implicit declaration we generate for explicit // specializations. FIXME: Do not generate these implicit declarations. Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp?rev=305379&r1=305378&r2=305379&view=diff ============================================================================== --- cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp (original) +++ cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp Wed Jun 14 05:07:02 2017 @@ -1782,6 +1782,12 @@ Decl *TemplateDeclInstantiator::VisitFun Previous.clear(); } + if (isFriend) { + Function->setObjectOfFriendDecl(); + if (FunctionTemplate) + FunctionTemplate->setObjectOfFriendDecl(); + } + SemaRef.CheckFunctionDeclaration(/*Scope*/ nullptr, Function, Previous, isExplicitSpecialization); @@ -1792,7 +1798,6 @@ Decl *TemplateDeclInstantiator::VisitFun // If the original function was part of a friend declaration, // inherit its namespace state and add it to the owner. if (isFriend) { - PrincipalDecl->setObjectOfFriendDecl(); DC->makeDeclVisibleInContext(PrincipalDecl); bool QueuedInstantiation = false; Modified: cfe/trunk/test/SemaCXX/friend2.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/friend2.cpp?rev=305379&r1=305378&r2=305379&view=diff ============================================================================== --- cfe/trunk/test/SemaCXX/friend2.cpp (original) +++ cfe/trunk/test/SemaCXX/friend2.cpp Wed Jun 14 05:07:02 2017 @@ -170,3 +170,15 @@ struct Test { template class Test<int>; } + +namespace pr14785 { +template<typename T> +struct Somewhat { + void internal() const { } + friend void operator+(int const &, Somewhat<T> const &) {} // expected-error{{redefinition of 'operator+'}} +}; + +void operator+(int const &, Somewhat<char> const &x) { // expected-note {{previous definition is here}} + x.internal(); // expected-note{{in instantiation of template class 'pr14785::Somewhat<char>' requested here}} +} +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
