Author: Hans Wennborg Date: 2026-07-02T09:35:57+02:00 New Revision: e7924d50db0ae1c584c975fc4f274960d93c92d2
URL: https://github.com/llvm/llvm-project/commit/e7924d50db0ae1c584c975fc4f274960d93c92d2 DIFF: https://github.com/llvm/llvm-project/commit/e7924d50db0ae1c584c975fc4f274960d93c92d2.diff LOG: [clang] Handle constructor closures with consteval default args (#203554) Fixes https://github.com/llvm/llvm-project/issues/201320 Just grabbing the default argument with `getDefaultArg()` during codegen doesn't work if the expression requires evaluating a consteval expression (see bug). Instead, we must properly BuildCXXDefaultArgExpr it during Sema, store it in the AST (including serialization/deserialization) and then use that during codegen. Added: clang/test/SemaCXX/ms-ctor-closure.cpp Modified: clang/include/clang/AST/ASTContext.h clang/include/clang/AST/DeclCXX.h clang/include/clang/Sema/Sema.h clang/lib/AST/ASTContext.cpp clang/lib/AST/DeclCXX.cpp clang/lib/CodeGen/MicrosoftCXXABI.cpp clang/lib/Sema/SemaDecl.cpp clang/lib/Sema/SemaDeclCXX.cpp clang/lib/Sema/SemaExprCXX.cpp clang/lib/Sema/SemaTemplateInstantiateDecl.cpp clang/lib/Serialization/ASTReaderDecl.cpp clang/lib/Serialization/ASTWriterDecl.cpp clang/test/CodeGenCXX/dllexport-ctor-closure.cpp clang/test/CodeGenCXX/microsoft-abi-throw.cpp Removed: ################################################################################ diff --git a/clang/include/clang/AST/ASTContext.h b/clang/include/clang/AST/ASTContext.h index a4ed852d36442..c04b380f9ec5b 100644 --- a/clang/include/clang/AST/ASTContext.h +++ b/clang/include/clang/AST/ASTContext.h @@ -514,6 +514,9 @@ class ASTContext : public RefCountedBase<ASTContext> { /// Declaration for the CUDA cudaLaunchDevice function. FunctionDecl *cudaLaunchDeviceDecl = nullptr; + llvm::DenseMap<const CXXConstructorDecl *, ArrayRef<CXXDefaultArgExpr *>> + CtorClosureDefaultArgs; + /// Keeps track of all declaration attributes. /// /// Since so few decls have attrs, we keep them in a hash map instead of @@ -1148,6 +1151,11 @@ class ASTContext : public RefCountedBase<ASTContext> { /// Erase the attributes corresponding to the given declaration. void eraseDeclAttrs(const Decl *D); + ArrayRef<CXXDefaultArgExpr *> + getCtorClosureDefaultArgs(const CXXConstructorDecl *CD); + void setCtorClosureDefaultArgs(const CXXConstructorDecl *CD, + ArrayRef<CXXDefaultArgExpr *> Args); + /// Get all ExplicitInstantiationDecls for a given specialization. ArrayRef<ExplicitInstantiationDecl *> getExplicitInstantiationDecls(const NamedDecl *Spec) const; diff --git a/clang/include/clang/AST/DeclCXX.h b/clang/include/clang/AST/DeclCXX.h index 28d171253dc03..4bf190e311395 100644 --- a/clang/include/clang/AST/DeclCXX.h +++ b/clang/include/clang/AST/DeclCXX.h @@ -2877,6 +2877,9 @@ class CXXConstructorDecl final return const_cast<CXXConstructorDecl*>(this)->getCanonicalDecl(); } + ArrayRef<CXXDefaultArgExpr *> getCtorClosureDefaultArgs() const; + void setCtorClosureDefaultArgs(ArrayRef<CXXDefaultArgExpr *> Args); + // Implement isa/cast/dyncast/etc. static bool classof(const Decl *D) { return classofKind(D->getKind()); } static bool classofKind(Kind K) { return K == CXXConstructor; } diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h index 2df85771573e2..f7d0d493e7081 100644 --- a/clang/include/clang/Sema/Sema.h +++ b/clang/include/clang/Sema/Sema.h @@ -14260,11 +14260,8 @@ class Sema final : public SemaBase { LateInstantiatedAttrVec *LateAttrs = nullptr, LocalInstantiationScope *OuterMostScope = nullptr); - /// In the MS ABI, we need to instantiate default arguments of dllexported - /// default constructors along with the constructor definition. This allows IR - /// gen to emit a constructor closure which calls the default constructor with - /// its default arguments. - void InstantiateDefaultCtorDefaultArgs(CXXConstructorDecl *Ctor); + bool BuildCtorClosureDefaultArgs(SourceLocation Loc, CXXConstructorDecl *Ctor, + bool IsCopy = false); bool InstantiateDefaultArgument(SourceLocation CallLoc, FunctionDecl *FD, ParmVarDecl *Param); diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp index abf0cd5e18c2b..a6eb87ab7d8aa 100644 --- a/clang/lib/AST/ASTContext.cpp +++ b/clang/lib/AST/ASTContext.cpp @@ -989,6 +989,8 @@ void ASTContext::cleanup() { A->second->~AttrVec(); DeclAttrs.clear(); + CtorClosureDefaultArgs.clear(); + for (const auto &Value : ModuleInitializers) Value.second->~PerModuleInitializers(); ModuleInitializers.clear(); @@ -1547,6 +1549,17 @@ void ASTContext::eraseDeclAttrs(const Decl *D) { } } +ArrayRef<CXXDefaultArgExpr *> +ASTContext::getCtorClosureDefaultArgs(const CXXConstructorDecl *CD) { + return CtorClosureDefaultArgs.lookup(CD); +} + +void ASTContext::setCtorClosureDefaultArgs(const CXXConstructorDecl *CD, + ArrayRef<CXXDefaultArgExpr *> Args) { + assert(!CtorClosureDefaultArgs.contains(CD)); + CtorClosureDefaultArgs[CD] = Args; +} + ArrayRef<ExplicitInstantiationDecl *> ASTContext::getExplicitInstantiationDecls(const NamedDecl *Spec) const { auto It = diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp index ce4ba971a4631..e7e0f75fdc84d 100644 --- a/clang/lib/AST/DeclCXX.cpp +++ b/clang/lib/AST/DeclCXX.cpp @@ -3133,6 +3133,16 @@ bool CXXConstructorDecl::isSpecializationCopyingObject() const { return ParamType == ClassTy; } +ArrayRef<CXXDefaultArgExpr *> +CXXConstructorDecl::getCtorClosureDefaultArgs() const { + return getASTContext().getCtorClosureDefaultArgs(getCanonicalDecl()); +} + +void CXXConstructorDecl::setCtorClosureDefaultArgs( + ArrayRef<CXXDefaultArgExpr *> Args) { + getASTContext().setCtorClosureDefaultArgs(getCanonicalDecl(), Args); +} + void CXXDestructorDecl::anchor() {} CXXDestructorDecl *CXXDestructorDecl::CreateDeserialized(ASTContext &C, diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp index 40c7c00d85395..d324580036f6a 100644 --- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp +++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp @@ -4207,18 +4207,17 @@ MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD, if (SrcVal) Args.add(RValue::get(SrcVal), SrcParam->getType()); - // Add the rest of the default arguments. + // Get the rest of the default arguments. SmallVector<const Stmt *, 4> ArgVec; - ArrayRef<ParmVarDecl *> params = CD->parameters().drop_front(IsCopy ? 1 : 0); - for (const ParmVarDecl *PD : params) { - assert(PD->hasDefaultArg() && "ctor closure lacks default args"); - ArgVec.push_back(PD->getDefaultArg()); - } + for (const CXXDefaultArgExpr *Expr : + CD->getCtorClosureDefaultArgs().drop_front(IsCopy ? 1 : 0)) + ArgVec.push_back(Expr); + assert(ArgVec.size() == CD->getNumParams() - IsCopy); CodeGenFunction::RunCleanupsScope Cleanups(CGF); const auto *FPT = CD->getType()->castAs<FunctionProtoType>(); - CGF.EmitCallArgs(Args, FPT, llvm::ArrayRef(ArgVec), CD, IsCopy ? 1 : 0); + CGF.EmitCallArgs(Args, FPT, ArrayRef(ArgVec), CD, IsCopy ? 1 : 0); // Insert any ABI-specific implicit constructor arguments. AddedStructorArgCounts ExtraArgs = diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp index f6d1d7a7877c7..9948a633d7e98 100644 --- a/clang/lib/Sema/SemaDecl.cpp +++ b/clang/lib/Sema/SemaDecl.cpp @@ -16306,7 +16306,8 @@ Decl *Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Decl *D, Context.getTargetInfo().getCXXABI().isMicrosoft()) { // If this is an MS ABI dllexport default constructor, instantiate any // default arguments. - InstantiateDefaultCtorDefaultArgs(Ctor); + if (DLLExportAttr *Attr = Ctor->getAttr<DLLExportAttr>()) + BuildCtorClosureDefaultArgs(Attr->getLocation(), Ctor); } } diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp index c645d96da5c00..c1caf9a58d650 100644 --- a/clang/lib/Sema/SemaDeclCXX.cpp +++ b/clang/lib/Sema/SemaDeclCXX.cpp @@ -6339,7 +6339,8 @@ static void ReferenceDllExportedMembers(Sema &S, CXXRecordDecl *Class) { if (S.Context.getTargetInfo().getCXXABI().isMicrosoft()) { auto *CD = dyn_cast<CXXConstructorDecl>(MD); if (CD && CD->isDefaultConstructor() && TSK == TSK_Undeclared) { - S.InstantiateDefaultCtorDefaultArgs(CD); + S.BuildCtorClosureDefaultArgs( + CD->getAttr<DLLExportAttr>()->getLocation(), CD); } } @@ -6392,10 +6393,8 @@ static void checkForMultipleExportedDefaultConstructors(Sema &S, // If the class is non-dependent, mark the default arguments as ODR-used so // that we can properly codegen the constructor closure. if (!Class->isDependentContext()) { - for (ParmVarDecl *PD : CD->parameters()) { - (void)S.CheckCXXDefaultArgExpr(Attr->getLocation(), CD, PD); - S.DiscardCleanupsInEvaluationContext(); - } + S.BuildCtorClosureDefaultArgs(Attr->getLocation(), CD); + S.DiscardCleanupsInEvaluationContext(); } if (LastExportedDefaultCtor) { @@ -19817,3 +19816,36 @@ void Sema::ActOnFinishFunctionDeclarationDeclarator(Declarator &Declarator) { } InventedParameterInfos.pop_back(); } + +bool Sema::BuildCtorClosureDefaultArgs(SourceLocation Loc, + CXXConstructorDecl *Ctor, bool IsCopy) { + assert(Context.getTargetInfo().getCXXABI().isMicrosoft()); + + if (!Ctor->getCtorClosureDefaultArgs().empty()) { + // If we build args for default constructor closures, those will have + // been generated *before* building args for any copy constructor closures. + assert(IsCopy || Ctor->getCtorClosureDefaultArgs()[0] != nullptr); + return false; + } + + unsigned NumParams = Ctor->getNumParams(); + if (NumParams == 0) + return false; + + CXXDefaultArgExpr **Args = + new (getASTContext()) CXXDefaultArgExpr *[NumParams]; + + if (IsCopy) + Args[0] = nullptr; // Copy ctor closure will provide the first argument. + + for (unsigned I = IsCopy ? 1 : 0; I != NumParams; ++I) { + ExprResult R = BuildCXXDefaultArgExpr(Loc, Ctor, Ctor->getParamDecl(I)); + CleanupVarDeclMarking(); + if (R.isInvalid()) + return true; + Args[I] = cast<CXXDefaultArgExpr>(R.get()); + } + + Ctor->setCtorClosureDefaultArgs(ArrayRef(Args, NumParams)); + return false; +} diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp index ea9e0b945081b..dc7f874927a8e 100644 --- a/clang/lib/Sema/SemaExprCXX.cpp +++ b/clang/lib/Sema/SemaExprCXX.cpp @@ -1070,10 +1070,8 @@ bool Sema::CheckCXXThrowOperand(SourceLocation ThrowLoc, // We don't keep the instantiated default argument expressions around so // we must rebuild them here. - for (unsigned I = 1, E = CD->getNumParams(); I != E; ++I) { - if (CheckCXXDefaultArgExpr(ThrowLoc, CD, CD->getParamDecl(I))) - return true; - } + if (BuildCtorClosureDefaultArgs(ThrowLoc, CD, /*IsCopy=*/true)) + return true; } } diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp index 37ef4acd5d3d9..c56203f10ac3c 100644 --- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp +++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp @@ -1078,22 +1078,6 @@ void Sema::updateAttrsForLateParsedTemplate(const Decl *Pattern, Decl *Inst) { } } -void Sema::InstantiateDefaultCtorDefaultArgs(CXXConstructorDecl *Ctor) { - assert(Context.getTargetInfo().getCXXABI().isMicrosoft() && - Ctor->isDefaultConstructor()); - unsigned NumParams = Ctor->getNumParams(); - if (NumParams == 0) - return; - DLLExportAttr *Attr = Ctor->getAttr<DLLExportAttr>(); - if (!Attr) - return; - for (unsigned I = 0; I != NumParams; ++I) { - (void)CheckCXXDefaultArgExpr(Attr->getLocation(), Ctor, - Ctor->getParamDecl(I)); - CleanupVarDeclMarking(); - } -} - /// Get the previous declaration of a declaration for the purposes of template /// instantiation. If this finds a previous declaration, then the previous /// declaration of the instantiation of D should be an instantiation of the @@ -5970,7 +5954,8 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation, // default arguments. if (Context.getTargetInfo().getCXXABI().isMicrosoft() && Ctor->isDefaultConstructor()) { - InstantiateDefaultCtorDefaultArgs(Ctor); + if (DLLExportAttr *Attr = Ctor->getAttr<DLLExportAttr>()) + BuildCtorClosureDefaultArgs(Attr->getLocation(), Ctor); } } diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp index fb291a4b0f2c5..a25e58e434bf2 100644 --- a/clang/lib/Serialization/ASTReaderDecl.cpp +++ b/clang/lib/Serialization/ASTReaderDecl.cpp @@ -2334,6 +2334,14 @@ void ASTDeclReader::VisitCXXConstructorDecl(CXXConstructorDecl *D) { InheritedConstructor(Shadow, Ctor); } + if (unsigned NumArgs = Record.readUInt32()) { + CXXDefaultArgExpr **Args = + new (Reader.getContext()) CXXDefaultArgExpr *[NumArgs]; + for (unsigned I = 0; I != NumArgs; I++) + Args[I] = cast<CXXDefaultArgExpr>(Record.readStmt()); + D->setCtorClosureDefaultArgs(ArrayRef(Args, NumArgs)); + } + VisitCXXMethodDecl(D); } diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp index 7f5005aa666c7..f271769d8edf6 100644 --- a/clang/lib/Serialization/ASTWriterDecl.cpp +++ b/clang/lib/Serialization/ASTWriterDecl.cpp @@ -1774,6 +1774,12 @@ void ASTDeclWriter::VisitCXXConstructorDecl(CXXConstructorDecl *D) { Record.AddDeclRef(Inherited.getConstructor()); } + ArrayRef<CXXDefaultArgExpr *> CtorClosureDefaultArgs = + D->getCtorClosureDefaultArgs(); + Record.push_back((unsigned)CtorClosureDefaultArgs.size()); + for (CXXDefaultArgExpr *Arg : CtorClosureDefaultArgs) + Record.writeStmtRef(Arg); + VisitCXXMethodDecl(D); Code = serialization::DECL_CXX_CONSTRUCTOR; } diff --git a/clang/test/CodeGenCXX/dllexport-ctor-closure.cpp b/clang/test/CodeGenCXX/dllexport-ctor-closure.cpp index 8aeb9b9176fcd..1b4940673f599 100644 --- a/clang/test/CodeGenCXX/dllexport-ctor-closure.cpp +++ b/clang/test/CodeGenCXX/dllexport-ctor-closure.cpp @@ -1,4 +1,4 @@ -// RUN: %clang_cc1 -triple i686-windows-msvc -emit-llvm -std=c++14 \ +// RUN: %clang_cc1 -triple i686-windows-msvc -emit-llvm -std=c++20 \ // RUN: -fno-threadsafe-statics -fms-extensions -O1 -mconstructor-aliases \ // RUN: -disable-llvm-passes -o - %s -w -fms-compatibility-version=19.00 | \ // RUN: FileCheck %s @@ -95,3 +95,10 @@ struct __declspec(dllexport) ConstexprDefaultArg { ConstexprDefaultArg(SomeStruct = kConstexprStruct) {} }; // CHECK-LABEL: define weak_odr dso_local dllexport x86_thiscallcc void @"??_FConstexprDefaultArg@@QAEXXZ" + +consteval int constEvalFunc() { return 42; } +struct ConstEvalDefaultArg { + __declspec(dllexport) ConstEvalDefaultArg(int n = constEvalFunc()) {} +}; +// CHECK-LABEL: define weak_odr dso_local dllexport x86_thiscallcc void @"??_FConstEvalDefaultArg@@QAEXXZ" +// CHECK: call {{.*}} @"??0ConstEvalDefaultArg@@QAE@H@Z"({{.*}}, i32 noundef 42) diff --git a/clang/test/CodeGenCXX/microsoft-abi-throw.cpp b/clang/test/CodeGenCXX/microsoft-abi-throw.cpp index 14945ad60f3c1..b37e2c2deec9d 100644 --- a/clang/test/CodeGenCXX/microsoft-abi-throw.cpp +++ b/clang/test/CodeGenCXX/microsoft-abi-throw.cpp @@ -1,4 +1,4 @@ -// RUN: %clang_cc1 -emit-llvm -o - -triple=i386-pc-win32 -std=c++11 %s -fcxx-exceptions -fms-extensions | FileCheck %s +// RUN: %clang_cc1 -emit-llvm -o - -triple=i386-pc-win32 -std=c++20 %s -fcxx-exceptions -fms-extensions | FileCheck %s // CHECK-DAG: @"??_R0?AUY@@@8" = linkonce_odr global %rtti.TypeDescriptor7 { ptr @"??_7type_info@@6B@", ptr null, [8 x i8] c".?AUY@@\00" }, comdat // CHECK-DAG: @"_CT??_R0?AUY@@@8??0Y@@QAE@ABU0@@Z8" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 4, ptr @"??_R0?AUY@@@8", i32 0, i32 -1, i32 0, i32 8, ptr @"??0Y@@QAE@ABU0@@Z" }, section ".xdata", comdat @@ -71,6 +71,32 @@ void h(Default &d) { throw d; } +consteval int constEvalFunc() { return 123; } +struct DefaultConstEval { + DefaultConstEval(DefaultConstEval&, int = constEvalFunc()); +}; +// CHECK-LABEL: @"??_ODefaultConstEval@@QAEXAAU0@@Z" +// CHECK: call x86_thiscallcc {{.*}} @"??0DefaultConstEval@@QAE@AAU0@H@Z"({{.*}} %[[this]], {{.*}} %[[src]], i32 noundef 123) + +void h2(DefaultConstEval &d) { + throw d; +} + +// This will generate both the default constructor closure and the copy constructor closure -- for the same constructor. +struct DefaultCtorIsCopyCtor; +const DefaultCtorIsCopyCtor& foo(); +struct DefaultCtorIsCopyCtor { + __declspec(dllexport) DefaultCtorIsCopyCtor(const DefaultCtorIsCopyCtor& = foo(), int = 456) {} +}; +void h3(DefaultCtorIsCopyCtor &d) { + throw d; +} +// CHECK-LABEL: @"??_FDefaultCtorIsCopyCtor@@QAEXXZ" +// CHECK: %[[foo:.*]] = call {{.*}} @"?foo@@YAABUDefaultCtorIsCopyCtor@@XZ" +// CHECK: call {{.*}} @"??0DefaultCtorIsCopyCtor@@QAE@ABU0@H@Z"({{.*}} %[[foo]], i32 noundef 456) +// CHECK-LABEL: @"??_ODefaultCtorIsCopyCtor@@QAEXABU0@@Z" +// CHECK: call {{.*}} @"??0DefaultCtorIsCopyCtor@@QAE@ABU0@H@Z"({{.*}} i32 noundef 456) + struct DeletedCopy { DeletedCopy(); DeletedCopy(DeletedCopy &&); diff --git a/clang/test/SemaCXX/ms-ctor-closure.cpp b/clang/test/SemaCXX/ms-ctor-closure.cpp new file mode 100644 index 0000000000000..05aa5d40b4427 --- /dev/null +++ b/clang/test/SemaCXX/ms-ctor-closure.cpp @@ -0,0 +1,10 @@ +// RUN: %clang_cc1 %s -triple=i386-pc-win32 -std=c++23 -fms-extensions -verify + +consteval int bad(int x) { return 42 / x; } // expected-note{{division by zero}} + +struct ExportedDefaultArgClosure { + __declspec(dllexport) // expected-note{{in the default initializer of 'x'}} + ExportedDefaultArgClosure(int x // expected-note{{declared here}} + = bad(0)) { // expected-error{{call to consteval function 'bad' is not a constant expression}} expected-note{{in call to 'bad(0)'}} + } +}; _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
