PR 12586: Fix assert while running libc++ testsuite: deal with exception

specifications on member function templates of class templates and other such
nested beasties. Store the function template from which we are to instantiate
an exception specification rather than trying to deduce it. Plus some
additional test cases.

llvm-svn: 155076

clang/include/clang/AST/Type.h

@@ -2701,7 +2701,8 @@ public:
     ExtProtoInfo() :
       Variadic(false), HasTrailingReturn(false), TypeQuals(0),
       ExceptionSpecType(EST_None), RefQualifier(RQ_None),
-      NumExceptions(0), Exceptions(0), NoexceptExpr(0), ExceptionSpecDecl(0),
+      NumExceptions(0), Exceptions(0), NoexceptExpr(0),
+      ExceptionSpecDecl(0), ExceptionSpecTemplate(0),
       ConsumedArguments(0) {}
 
     FunctionType::ExtInfo ExtInfo;
@@ -2714,6 +2715,7 @@ public:
     const QualType *Exceptions;
     Expr *NoexceptExpr;
     FunctionDecl *ExceptionSpecDecl;
+    FunctionDecl *ExceptionSpecTemplate;
     const bool *ConsumedArguments;
   };
 
@@ -2759,9 +2761,10 @@ private:
   // NoexceptExpr - Instead of Exceptions, there may be a single Expr* pointing
   // to the expression in the noexcept() specifier.
 
-  // ExceptionSpecDecl - Instead of Exceptions, there may be a single
+  // ExceptionSpecDecl, ExceptionSpecTemplate - Instead of Exceptions, there may
-  // FunctionDecl* pointing to the function which should be used to resolve
+  // be a pair of FunctionDecl* pointing to the function which should be used to
-  // this function type's exception specification.
+  // instantiate this function type's exception specification, and the function
+  // from which it should be instantiated.
 
   // ConsumedArgs - A variable size array, following Exceptions
   // and of length NumArgs, holding flags indicating which arguments
@@ -2804,6 +2807,7 @@ public:
       EPI.NoexceptExpr = getNoexceptExpr();
     } else if (EPI.ExceptionSpecType == EST_Uninstantiated) {
       EPI.ExceptionSpecDecl = getExceptionSpecDecl();
+      EPI.ExceptionSpecTemplate = getExceptionSpecTemplate();
     }
     if (hasAnyConsumedArgs())
       EPI.ConsumedArguments = getConsumedArgsBuffer();
@@ -2847,10 +2851,22 @@ public:
     // NoexceptExpr sits where the arguments end.
     return *reinterpret_cast<Expr *const *>(arg_type_end());
   }
+  /// \brief If this function type has an uninstantiated exception
+  /// specification, this is the function whose exception specification
+  /// is represented by this type.
   FunctionDecl *getExceptionSpecDecl() const {
     if (getExceptionSpecType() != EST_Uninstantiated)
       return 0;
-    return *reinterpret_cast<FunctionDecl * const *>(arg_type_end());
+    return reinterpret_cast<FunctionDecl * const *>(arg_type_end())[0];
+  }
+  /// \brief If this function type has an uninstantiated exception
+  /// specification, this is the function whose exception specification
+  /// should be instantiated to find the exception specification for
+  /// this type.
+  FunctionDecl *getExceptionSpecTemplate() const {
+    if (getExceptionSpecType() != EST_Uninstantiated)
+      return 0;
+    return reinterpret_cast<FunctionDecl * const *>(arg_type_end())[1];
   }
   bool isNothrow(ASTContext &Ctx) const {
     ExceptionSpecificationType EST = getExceptionSpecType();

clang/lib/AST/ASTContext.cpp

@@ -2195,7 +2195,7 @@ ASTContext::getFunctionType(QualType ResultTy,
   else if (EPI.ExceptionSpecType == EST_ComputedNoexcept) {
     Size += sizeof(Expr*);
   } else if (EPI.ExceptionSpecType == EST_Uninstantiated) {
-    Size += sizeof(FunctionDecl*);
+    Size += 2 * sizeof(FunctionDecl*);
   }
   if (EPI.ConsumedArguments)
     Size += NumArgs * sizeof(bool);

clang/lib/AST/Type.cpp

@@ -1550,7 +1550,8 @@ FunctionProtoType::FunctionProtoType(QualType result, const QualType *args,
     // Store the function decl from which we will resolve our
     // exception specification.
     FunctionDecl **slot = reinterpret_cast<FunctionDecl**>(argSlot + numArgs);
-    *slot = epi.ExceptionSpecDecl;
+    slot[0] = epi.ExceptionSpecDecl;
+    slot[1] = epi.ExceptionSpecTemplate;
     // This exception specification doesn't make the type dependent, because
     // it's not instantiated as part of instantiating the type.
   }

clang/lib/Sema/SemaExpr.cpp

@@ -9776,9 +9776,8 @@ void Sema::MarkFunctionReferenced(SourceLocation Loc, FunctionDecl *Func) {
 
   // Instantiate the exception specification for any function which is
   // used: CodeGen will need it.
-  if (Func->getTemplateInstantiationPattern() &&
+  const FunctionProtoType *FPT = Func->getType()->getAs<FunctionProtoType>();
-      Func->getType()->castAs<FunctionProtoType>()->getExceptionSpecType()
+  if (FPT && FPT->getExceptionSpecType() == EST_Uninstantiated)
-        == EST_Uninstantiated)
     InstantiateExceptionSpec(Loc, Func);
 
   // Implicit instantiation of function templates and member functions of

clang/lib/Sema/SemaTemplateInstantiateDecl.cpp

@@ -2251,6 +2251,8 @@ static void addInstantiatedParametersToScope(Sema &S, FunctionDecl *Function,
 static void InstantiateExceptionSpec(Sema &SemaRef, FunctionDecl *New,
                                      const FunctionProtoType *Proto,
                            const MultiLevelTemplateArgumentList &TemplateArgs) {
+  assert(Proto->getExceptionSpecType() != EST_Uninstantiated);
+
   // C++11 [expr.prim.general]p3:
   //   If a declaration declares a member function or member function 
   //   template of a class X, the expression this is a prvalue of type 
@@ -2377,20 +2379,8 @@ static void InstantiateExceptionSpec(Sema &SemaRef, FunctionDecl *New,
 
 void Sema::InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
                                     FunctionDecl *Decl) {
-  // Find the template declaration which contains the exception specification.
+  const FunctionProtoType *Proto = Decl->getType()->castAs<FunctionProtoType>();
-  // Per [except.spec]p4, prefer the exception spec on the primary template
+  if (Proto->getExceptionSpecType() != EST_Uninstantiated)
-  // if this is an explicit instantiation.
-  FunctionDecl *Tmpl = 0;
-  if (Decl->getPrimaryTemplate())
-    Tmpl = Decl->getPrimaryTemplate()->getTemplatedDecl();
-  else if (FunctionDecl *MemTmpl = Decl->getInstantiatedFromMemberFunction())
-    Tmpl = MemTmpl;
-  else
-    Tmpl = Decl->getTemplateInstantiationPattern();
-  assert(Tmpl && "can't instantiate non-template");
-
-  if (Decl->getType()->castAs<FunctionProtoType>()->getExceptionSpecType()
-        != EST_Uninstantiated)
     return;
 
   InstantiatingTemplate Inst(*this, PointOfInstantiation, Decl,
@@ -2406,10 +2396,12 @@ void Sema::InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
   MultiLevelTemplateArgumentList TemplateArgs =
     getTemplateInstantiationArgs(Decl, 0, /*RelativeToPrimary*/true);
 
-  addInstantiatedParametersToScope(*this, Decl, Tmpl, Scope, TemplateArgs);
+  FunctionDecl *Template = Proto->getExceptionSpecTemplate();
+  addInstantiatedParametersToScope(*this, Decl, Template, Scope, TemplateArgs);
 
-  const FunctionProtoType *Proto = Tmpl->getType()->castAs<FunctionProtoType>();
+  ::InstantiateExceptionSpec(*this, Decl,
-  ::InstantiateExceptionSpec(*this, Decl, Proto, TemplateArgs);
+                             Template->getType()->castAs<FunctionProtoType>(),
+                             TemplateArgs);
 }
 
 /// \brief Initializes the common fields of an instantiation function
@@ -2457,6 +2449,10 @@ TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
         EPI.ExceptionSpecType != EST_None &&
         EPI.ExceptionSpecType != EST_DynamicNone &&
         EPI.ExceptionSpecType != EST_BasicNoexcept) {
+      FunctionDecl *ExceptionSpecTemplate = Tmpl;
+      if (EPI.ExceptionSpecType == EST_Uninstantiated)
+        ExceptionSpecTemplate = EPI.ExceptionSpecTemplate;
+
       // Mark the function has having an uninstantiated exception specification.
       const FunctionProtoType *NewProto
         = New->getType()->getAs<FunctionProtoType>();
@@ -2464,6 +2460,7 @@ TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
       EPI = NewProto->getExtProtoInfo();
       EPI.ExceptionSpecType = EST_Uninstantiated;
       EPI.ExceptionSpecDecl = New;
+      EPI.ExceptionSpecTemplate = ExceptionSpecTemplate;
       New->setType(SemaRef.Context.getFunctionType(NewProto->getResultType(),
                                                    NewProto->arg_type_begin(),
                                                    NewProto->getNumArgs(),

clang/test/CodeGenCXX/cxx11-exception-spec.cpp

@@ -3,9 +3,11 @@
 void h();
 
 template<typename T> void f() noexcept(sizeof(T) == 4) { h(); }
+template<typename T> void g() noexcept(sizeof(T) == 4);
 
 template<typename T> struct S {
   static void f() noexcept(sizeof(T) == 4) { h(); }
+  static void g() noexcept(sizeof(T) == 4);
 };
 
 // CHECK: define {{.*}} @_Z1fIsEvv() {
@@ -30,7 +32,7 @@ template void S<char16_t>::f();
 // CHECK: define {{.*}} @_ZN1SIA2_DsE1fEv() nounwind
 template void S<char16_t[2]>::f();
 
-void g() {
+void h() {
   // CHECK: define {{.*}} @_Z1fIiEvv() nounwind {
   f<int>();
   // CHECK: define {{.*}} @_Z1fIA2_iEvv() {
@@ -64,3 +66,55 @@ void g() {
   // CHECK-NOT: nounwind
   (void)&S<char>::f;
 }
+
+// CHECK: define {{.*}} @_Z1iv
+void i() {
+  // CHECK: declare {{.*}} @_Z1gIiEvv() nounwind
+  g<int>();
+  // CHECK: declare {{.*}} @_Z1gIA2_iEvv()
+  // CHECK-NOT: nounwind
+  g<int[2]>();
+
+  // CHECK: declare {{.*}} @_ZN1SIiE1gEv() nounwind
+  S<int>::g();
+  // CHECK: declare {{.*}} @_ZN1SIA2_iE1gEv()
+  // CHECK-NOT: nounwind
+  S<int[2]>::g();
+
+  // CHECK: declare {{.*}} @_Z1gIfEvv() nounwind
+  void (*g1)() = &g<float>;
+  // CHECK: declare {{.*}} @_Z1gIdEvv()
+  // CHECK-NOT: nounwind
+  void (*g2)() = &g<double>;
+
+  // CHECK: declare {{.*}} @_ZN1SIfE1gEv() nounwind
+  void (*g3)() = &S<float>::g;
+  // CHECK: declare {{.*}} @_ZN1SIdE1gEv()
+  // CHECK-NOT: nounwind
+  void (*g4)() = &S<double>::g;
+
+  // CHECK: declare {{.*}} @_Z1gIA4_cEvv() nounwind
+  (void)&g<char[4]>;
+  // CHECK: declare {{.*}} @_Z1gIcEvv()
+  // CHECK-NOT: nounwind
+  (void)&g<char>;
+
+  // CHECK: declare {{.*}} @_ZN1SIA4_cE1gEv() nounwind
+  (void)&S<char[4]>::g;
+  // CHECK: declare {{.*}} @_ZN1SIcE1gEv()
+  // CHECK-NOT: nounwind
+  (void)&S<char>::g;
+}
+
+template<typename T> struct Nested {
+  template<bool b, typename U> void f() noexcept(sizeof(T) == sizeof(U));
+};
+
+// CHECK: define {{.*}} @_Z1jv
+void j() {
+  // CHECK: declare {{.*}} @_ZN6NestedIiE1fILb1EcEEvv(
+  // CHECK-NOT: nounwind
+  Nested<int>().f<true, char>();
+  // CHECK: declare {{.*}} @_ZN6NestedIlE1fILb0ElEEvv({{.*}}) nounwind
+  Nested<long>().f<false, long>();
+}

clang/test/SemaTemplate/instantiate-exception-spec-cxx11.cpp

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -ftemplate-depth 16 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -ftemplate-depth 16 -fcxx-exceptions -fexceptions %s
 
 // DR1330: an exception specification for a function template is only
 // instantiated when it is needed.
@@ -31,7 +31,7 @@ decltype(S<0>::recurse()) *pVoid1 = 0; // ok, exception spec not needed
 decltype(&S<0>::recurse) pFn = 0; // ok, exception spec not needed
 
 template<> struct S<10> {};
-void (*pFn2)() noexcept = &S<0>::recurse; // expected-note {{instantiation of exception spec}}
+void (*pFn2)() noexcept = &S<0>::recurse; // expected-note {{instantiation of exception spec}} expected-error {{not superset}}
 
 
 template<typename T> T go(T a) noexcept(noexcept(go(a))); // \
@@ -118,3 +118,16 @@ namespace pr9485 {
     f2(0); // expected-error {{ambiguous}}
   }
 }
+
+struct Exc1 { char c[4]; };
+struct Exc2 { double x, y, z; };
+struct Base {
+  virtual void f() noexcept; // expected-note {{overridden}}
+};
+template<typename T> struct Derived : Base {
+  void f() noexcept (sizeof(T) == 4); // expected-error {{is more lax}}
+  void g() noexcept (T::error);
+};
+
+Derived<Exc1> d1; // ok
+Derived<Exc2> d2; // expected-note {{in instantiation of}}