PR14558: Compute triviality of special members (etc) at the end of the class

definition, rather than at the end of the definition of the set of nested
classes. We still defer checking of the user-specified exception specification
to the end of the nesting -- we can't check that until we've parsed the
in-class initializers for non-static data members.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@169805 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 16360e5e8cd8d183d72fdc922c6c37f4646fb714..047804ae4f6f9b2aecf11836d698eb136a88bcf9 100644 (file)
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -366,6 +366,16 @@ public:
                               const CXXDestructorDecl*>, 2>
       DelayedDestructorExceptionSpecChecks;
 
+  /// \brief All the members seen during a class definition which were both
+  /// explicitly defaulted and had explicitly-specified exception
+  /// specifications, along with the function type containing their
+  /// user-specified exception specification. Those exception specifications
+  /// were overridden with the default specifications, but we still need to
+  /// check whether they are compatible with the default specification, and
+  /// we can't do that until the nesting set of class definitions is complete.
+  SmallVector<std::pair<CXXMethodDecl*, const FunctionProtoType*>, 2>
+    DelayedDefaultedMemberExceptionSpecs;
+
   /// \brief Callback to the parser to parse templated functions when needed.
   typedef void LateTemplateParserCB(void *P, const FunctionDecl *FD);
   LateTemplateParserCB *LateTemplateParser;
@@ -4441,8 +4451,10 @@ public:
                                  StorageClass& SC);
   Decl *ActOnConversionDeclarator(CXXConversionDecl *Conversion);
 
-  void CheckExplicitlyDefaultedAndDeletedMethods(CXXRecordDecl *Record);
   void CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD);
+  void CheckExplicitlyDefaultedMemberExceptionSpec(CXXMethodDecl *MD,
+                                                   const FunctionProtoType *T);
+  void CheckDelayedExplicitlyDefaultedMemberExceptionSpecs();
 
   //===--------------------------------------------------------------------===//
   // C++ Derived Classes

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 2fae8c9f91bb1811726f747446a5e4988adaa563..027491cbbe41174aa2c66f912e07667aec698d56 100644 (file)
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -3981,14 +3981,69 @@ void Sema::CheckCompletedCXXClass(CXXRecordDecl *Record) {
     DiagnoseAbstractType(Record);
   }
 
-  // See if a method overloads virtual methods in a base
-  /// class without overriding any.
   if (!Record->isDependentType()) {
     for (CXXRecordDecl::method_iterator M = Record->method_begin(),
                                      MEnd = Record->method_end();
          M != MEnd; ++M) {
+      // See if a method overloads virtual methods in a base
+      // class without overriding any.
       if (!M->isStatic())
         DiagnoseHiddenVirtualMethods(Record, *M);
+
+      // Check whether the explicitly-defaulted special members are valid.
+      if (!M->isInvalidDecl() && M->isExplicitlyDefaulted())
+        CheckExplicitlyDefaultedSpecialMember(*M);
+
+      // For an explicitly defaulted or deleted special member, we defer
+      // determining triviality until the class is complete. That time is now!
+      if (!M->isImplicit() && !M->isUserProvided()) {
+        CXXSpecialMember CSM = getSpecialMember(*M);
+        if (CSM != CXXInvalid) {
+          M->setTrivial(SpecialMemberIsTrivial(*M, CSM));
+
+          // Inform the class that we've finished declaring this member.
+          Record->finishedDefaultedOrDeletedMember(*M);
+        }
+      }
+    }
+  }
+
+  // C++11 [dcl.constexpr]p8: A constexpr specifier for a non-static member
+  // function that is not a constructor declares that member function to be
+  // const. [...] The class of which that function is a member shall be
+  // a literal type.
+  //
+  // If the class has virtual bases, any constexpr members will already have
+  // been diagnosed by the checks performed on the member declaration, so
+  // suppress this (less useful) diagnostic.
+  //
+  // We delay this until we know whether an explicitly-defaulted (or deleted)
+  // destructor for the class is trivial.
+  if (LangOpts.CPlusPlus0x && !Record->isDependentType() &&
+      !Record->isLiteral() && !Record->getNumVBases()) {
+    for (CXXRecordDecl::method_iterator M = Record->method_begin(),
+                                     MEnd = Record->method_end();
+         M != MEnd; ++M) {
+      if (M->isConstexpr() && M->isInstance() && !isa<CXXConstructorDecl>(*M)) {
+        switch (Record->getTemplateSpecializationKind()) {
+        case TSK_ImplicitInstantiation:
+        case TSK_ExplicitInstantiationDeclaration:
+        case TSK_ExplicitInstantiationDefinition:
+          // If a template instantiates to a non-literal type, but its members
+          // instantiate to constexpr functions, the template is technically
+          // ill-formed, but we allow it for sanity.
+          continue;
+
+        case TSK_Undeclared:
+        case TSK_ExplicitSpecialization:
+          RequireLiteralType(M->getLocation(), Context.getRecordType(Record),
+                             diag::err_constexpr_method_non_literal);
+          break;
+        }
+
+        // Only produce one error per class.
+        break;
+      }
     }
   }
 
@@ -4002,27 +4057,6 @@ void Sema::CheckCompletedCXXClass(CXXRecordDecl *Record) {
   DeclareInheritedConstructors(Record);
 }
 
-void Sema::CheckExplicitlyDefaultedAndDeletedMethods(CXXRecordDecl *Record) {
-  for (CXXRecordDecl::method_iterator MI = Record->method_begin(),
-                                      ME = Record->method_end();
-       MI != ME; ++MI) {
-    if (!MI->isInvalidDecl() && MI->isExplicitlyDefaulted())
-      CheckExplicitlyDefaultedSpecialMember(*MI);
-
-    if (!MI->isImplicit() && !MI->isUserProvided()) {
-      // For an explicitly defaulted or deleted special member, we defer
-      // determining triviality until the class is complete. That time is now!
-      CXXSpecialMember CSM = getSpecialMember(*MI);
-      if (CSM != CXXInvalid) {
-        MI->setTrivial(SpecialMemberIsTrivial(*MI, CSM));
-
-        // Inform the class that we've finished declaring this member.
-        Record->finishedDefaultedOrDeletedMember(*MI);
-      }
-    }
-  }
-}
-
 /// Is the special member function which would be selected to perform the
 /// specified operation on the specified class type a constexpr constructor?
 static bool specialMemberIsConstexpr(Sema &S, CXXRecordDecl *ClassDecl,
@@ -4271,16 +4305,6 @@ void Sema::CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD) {
     HadError = true;
   }
 
-  // Rebuild the type with the implicit exception specification added, if we
-  // are going to need it.
-  const FunctionProtoType *ImplicitType = 0;
-  if (First || Type->hasExceptionSpec()) {
-    FunctionProtoType::ExtProtoInfo EPI = Type->getExtProtoInfo();
-    computeImplicitExceptionSpec(*this, MD->getLocation(), MD).getEPI(EPI);
-    ImplicitType = cast<FunctionProtoType>(
-      Context.getFunctionType(ReturnType, &ArgType, ExpectedParams, EPI));
-  }
-
   // C++11 [dcl.fct.def.default]p2:
   //   An explicitly-defaulted function may be declared constexpr only if it
   //   would have been implicitly declared as constexpr,
@@ -4295,13 +4319,17 @@ void Sema::CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD) {
     // FIXME: Explain why the constructor can't be constexpr.
     HadError = true;
   }
+
   //   and may have an explicit exception-specification only if it is compatible
   //   with the exception-specification on the implicit declaration.
-  if (Type->hasExceptionSpec() &&
-      CheckEquivalentExceptionSpec(
-        PDiag(diag::err_incorrect_defaulted_exception_spec) << CSM,
-        PDiag(), ImplicitType, SourceLocation(), Type, MD->getLocation()))
-    HadError = true;
+  if (Type->hasExceptionSpec()) {
+    // Delay the check if this is the first declaration of the special member,
+    // since we may not have parsed some necessary in-class initializers yet.
+    if (First)
+      DelayedDefaultedMemberExceptionSpecs.push_back(std::make_pair(MD, Type));
+    else
+      CheckExplicitlyDefaultedMemberExceptionSpec(MD, Type);
+  }
 
   //   If a function is explicitly defaulted on its first declaration,
   if (First) {
@@ -4311,7 +4339,11 @@ void Sema::CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD) {
 
     //  -- it is implicitly considered to have the same exception-specification
     //     as if it had been implicitly declared,
-    MD->setType(QualType(ImplicitType, 0));
+    FunctionProtoType::ExtProtoInfo EPI = Type->getExtProtoInfo();
+    EPI.ExceptionSpecType = EST_Unevaluated;
+    EPI.ExceptionSpecDecl = MD;
+    MD->setType(Context.getFunctionType(ReturnType, &ArgType,
+                                        ExpectedParams, EPI));
   }
 
   if (ShouldDeleteSpecialMember(MD, CSM)) {
@@ -4330,6 +4362,36 @@ void Sema::CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD) {
     MD->setInvalidDecl();
 }
 
+/// Check whether the exception specification provided for an
+/// explicitly-defaulted special member matches the exception specification
+/// that would have been generated for an implicit special member, per
+/// C++11 [dcl.fct.def.default]p2.
+void Sema::CheckExplicitlyDefaultedMemberExceptionSpec(
+    CXXMethodDecl *MD, const FunctionProtoType *SpecifiedType) {
+  // Compute the implicit exception specification.
+  FunctionProtoType::ExtProtoInfo EPI;
+  computeImplicitExceptionSpec(*this, MD->getLocation(), MD).getEPI(EPI);
+  const FunctionProtoType *ImplicitType = cast<FunctionProtoType>(
+    Context.getFunctionType(Context.VoidTy, 0, 0, EPI));
+
+  // Ensure that it matches.
+  CheckEquivalentExceptionSpec(
+    PDiag(diag::err_incorrect_defaulted_exception_spec)
+      << getSpecialMember(MD), PDiag(),
+    ImplicitType, SourceLocation(),
+    SpecifiedType, MD->getLocation());
+}
+
+void Sema::CheckDelayedExplicitlyDefaultedMemberExceptionSpecs() {
+  for (unsigned I = 0, N = DelayedDefaultedMemberExceptionSpecs.size();
+       I != N; ++I)
+    CheckExplicitlyDefaultedMemberExceptionSpec(
+      DelayedDefaultedMemberExceptionSpecs[I].first,
+      DelayedDefaultedMemberExceptionSpecs[I].second);
+
+  DelayedDefaultedMemberExceptionSpecs.clear();
+}
+
 namespace {
 struct SpecialMemberDeletionInfo {
   Sema &S;
@@ -7500,52 +7562,9 @@ void Sema::DefineImplicitDefaultConstructor(SourceLocation CurrentLocation,
 }
 
 void Sema::ActOnFinishDelayedMemberInitializers(Decl *D) {
-  if (!D) return;
-  AdjustDeclIfTemplate(D);
-
-  CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(D);
-
-  if (!ClassDecl->isDependentType())
-    CheckExplicitlyDefaultedAndDeletedMethods(ClassDecl);
-
-  // C++11 [dcl.constexpr]p8: A constexpr specifier for a non-static member
-  // function that is not a constructor declares that member function to be
-  // const. [...] The class of which that function is a member shall be
-  // a literal type.
-  //
-  // If the class has virtual bases, any constexpr members will already have
-  // been diagnosed by the checks performed on the member declaration, so
-  // suppress this (less useful) diagnostic.
-  //
-  // We delay this until we know whether an explicitly-defaulted (or deleted)
-  // destructor for the class is trivial.
-  if (LangOpts.CPlusPlus0x && !ClassDecl->isDependentType() &&
-      !ClassDecl->isLiteral() && !ClassDecl->getNumVBases()) {
-    for (CXXRecordDecl::method_iterator M = ClassDecl->method_begin(),
-                                     MEnd = ClassDecl->method_end();
-         M != MEnd; ++M) {
-      if (M->isConstexpr() && M->isInstance() && !isa<CXXConstructorDecl>(*M)) {
-        switch (ClassDecl->getTemplateSpecializationKind()) {
-        case TSK_ImplicitInstantiation:
-        case TSK_ExplicitInstantiationDeclaration:
-        case TSK_ExplicitInstantiationDefinition:
-          // If a template instantiates to a non-literal type, but its members
-          // instantiate to constexpr functions, the template is technically
-          // ill-formed, but we allow it for sanity.
-          continue;
-
-        case TSK_Undeclared:
-        case TSK_ExplicitSpecialization:
-          RequireLiteralType(M->getLocation(), Context.getRecordType(ClassDecl),
-                             diag::err_constexpr_method_non_literal);
-          break;
-        }
-
-        // Only produce one error per class.
-        break;
-      }
-    }
-  }
+  // Check that any explicitly-defaulted methods have exception specifications
+  // compatible with their implicit exception specifications.
+  CheckDelayedExplicitlyDefaultedMemberExceptionSpecs();
 }
 
 void Sema::DeclareInheritedConstructors(CXXRecordDecl *ClassDecl) {
@@ -10882,6 +10901,11 @@ void Sema::SetDeclDefaulted(Decl *Dcl, SourceLocation DefaultLoc) {
 
     CheckExplicitlyDefaultedSpecialMember(MD);
 
+    // The exception specification is needed because we are defining the
+    // function.
+    ResolveExceptionSpec(DefaultLoc,
+                         MD->getType()->castAs<FunctionProtoType>());
+
     switch (Member) {
     case CXXDefaultConstructor: {
       CXXConstructorDecl *CD = cast<CXXConstructorDecl>(MD);

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 337534eaac351549f508b0098aeaa8ad1ee3f92b..566f6eef7fab7f43be1b0e8ea6475b369c331889 100644 (file)
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2782,7 +2782,6 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
 
   EnterExpressionEvaluationContext EvalContext(*this,
                                                Sema::PotentiallyEvaluated);
-  ActOnStartOfFunctionDef(0, Function);
 
   // Introduce a new scope where local variable instantiations will be
   // recorded, unless we're actually a member function within a local
@@ -2794,21 +2793,21 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
 
   LocalInstantiationScope Scope(*this, MergeWithParentScope);
 
-  // Enter the scope of this instantiation. We don't use
-  // PushDeclContext because we don't have a scope.
-  Sema::ContextRAII savedContext(*this, Function);
+  if (PatternDecl->isDefaulted())
+    SetDeclDefaulted(Function, PatternDecl->getLocation());
+  else {
+    ActOnStartOfFunctionDef(0, Function);
 
-  MultiLevelTemplateArgumentList TemplateArgs =
-    getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
+    // Enter the scope of this instantiation. We don't use
+    // PushDeclContext because we don't have a scope.
+    Sema::ContextRAII savedContext(*this, Function);
 
-  addInstantiatedParametersToScope(*this, Function, PatternDecl, Scope,
-                                   TemplateArgs);
+    MultiLevelTemplateArgumentList TemplateArgs =
+      getTemplateInstantiationArgs(Function, 0, false, PatternDecl);
 
-  if (PatternDecl->isDefaulted()) {
-    ActOnFinishFunctionBody(Function, 0, /*IsInstantiation=*/true);
+    addInstantiatedParametersToScope(*this, Function, PatternDecl, Scope,
+                                     TemplateArgs);
 
-    SetDeclDefaulted(Function, PatternDecl->getLocation());
-  } else {
     // If this is a constructor, instantiate the member initializers.
     if (const CXXConstructorDecl *Ctor =
           dyn_cast<CXXConstructorDecl>(PatternDecl)) {
@@ -2824,11 +2823,11 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
 
     ActOnFinishFunctionBody(Function, Body.get(),
                             /*IsInstantiation=*/true);
-  }
 
-  PerformDependentDiagnostics(PatternDecl, TemplateArgs);
+    PerformDependentDiagnostics(PatternDecl, TemplateArgs);
 
-  savedContext.pop();
+    savedContext.pop();
+  }
 
   DeclGroupRef DG(Function);
   Consumer.HandleTopLevelDecl(DG);

diff --git a/test/CXX/special/class.ctor/p5-0x.cpp b/test/CXX/special/class.ctor/p5-0x.cpp
index ab8fdb0f1bd9e04c127c56d210d3c9cc1ceee47e..0f4add8c97423057000ad82d3ebcbe7534928987 100644 (file)
--- a/test/CXX/special/class.ctor/p5-0x.cpp
+++ b/test/CXX/special/class.ctor/p5-0x.cpp
@@ -195,3 +195,15 @@ static_assert(__has_trivial_constructor(Trivial4<int>), "Trivial4 is trivial");
 
 template<typename T> class Trivial5 { Trivial5() = delete; };
 static_assert(__has_trivial_constructor(Trivial5<int>), "Trivial5 is trivial");
+
+namespace PR14558 {
+  // Ensure we determine whether an explicitly-defaulted or deleted special
+  // member is trivial before we return to parsing the containing class.
+  struct A {
+    struct B { B() = default; } b;
+    struct C { C() = delete; } c;
+  };
+
+  static_assert(__has_trivial_constructor(A), "");
+  static_assert(__has_trivial_constructor(A::B), "");
+}

diff --git a/unittests/AST/DeclPrinterTest.cpp b/unittests/AST/DeclPrinterTest.cpp
index 50aab032120823b65b739c6d59a78f089457b05f..844b9a49e13adfbe077a30d5da91285f258fb6cd 100644 (file)
--- a/unittests/AST/DeclPrinterTest.cpp
+++ b/unittests/AST/DeclPrinterTest.cpp
@@ -476,8 +476,7 @@ TEST(DeclPrinter, TestCXXConstructorDecl8) {
     "  A() = default;"
     "};",
     constructorDecl(ofClass(hasName("A"))).bind("id"),
-    "A() noexcept = default"));
-    // Should be: "A() = default;" if we care about noexcept as written
+    "A() = default"));
 }
 
 TEST(DeclPrinter, TestCXXConstructorDecl9) {