Attributes on K&R C functions should not cause incompatible function type with a...

This patch fixes PR31020.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@294861 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/AST/Type.h b/include/clang/AST/Type.h
index 0a50b618c98448adedd0593756955394fed82530..0db0905cba980a4ad192c0a4089f7e4859f2d131 100644 (file)
--- a/include/clang/AST/Type.h
+++ b/include/clang/AST/Type.h
@@ -1888,6 +1888,13 @@ public:
   /// immediately following this class.
   template <typename T> const T *getAs() const;
 
+  /// Member-template getAsAdjusted<specific type>. Look through specific kinds
+  /// of sugar (parens, attributes, etc) for an instance of \<specific type>.
+  /// This is used when you need to walk over sugar nodes that represent some
+  /// kind of type adjustment from a type that was written as a \<specific type>
+  /// to another type that is still canonically a \<specific type>.
+  template <typename T> const T *getAsAdjusted() const;
+
   /// A variant of getAs<> for array types which silently discards
   /// qualifiers from the outermost type.
   const ArrayType *getAsArrayTypeUnsafe() const;
@@ -6008,6 +6015,38 @@ template <typename T> const T *Type::getAs() const {
   return cast<T>(getUnqualifiedDesugaredType());
 }
 
+template <typename T> const T *Type::getAsAdjusted() const {
+  static_assert(!TypeIsArrayType<T>::value, "ArrayType cannot be used with getAsAdjusted!");
+
+  // If this is directly a T type, return it.
+  if (const T *Ty = dyn_cast<T>(this))
+    return Ty;
+
+  // If the canonical form of this type isn't the right kind, reject it.
+  if (!isa<T>(CanonicalType))
+    return nullptr;
+
+  // Strip off type adjustments that do not modify the underlying nature of the
+  // type.
+  const Type *Ty = this;
+  while (Ty) {
+    if (const auto *A = dyn_cast<AttributedType>(Ty))
+      Ty = A->getModifiedType().getTypePtr();
+    else if (const auto *E = dyn_cast<ElaboratedType>(Ty))
+      Ty = E->desugar().getTypePtr();
+    else if (const auto *P = dyn_cast<ParenType>(Ty))
+      Ty = P->desugar().getTypePtr();
+    else if (const auto *A = dyn_cast<AdjustedType>(Ty))
+      Ty = A->desugar().getTypePtr();
+    else
+      break;
+  }
+
+  // Just because the canonical type is correct does not mean we can use cast<>,
+  // since we may not have stripped off all the sugar down to the base type.
+  return dyn_cast<T>(Ty);
+}
+
 inline const ArrayType *Type::getAsArrayTypeUnsafe() const {
   // If this is directly an array type, return it.
   if (const ArrayType *arr = dyn_cast<ArrayType>(this))

diff --git a/include/clang/AST/TypeLoc.h b/include/clang/AST/TypeLoc.h
index a10b9792d99343006dc0d43e4e2be5e3677423f3..946e555a5066f466de3e819113171cec54c87bba 100644 (file)
--- a/include/clang/AST/TypeLoc.h
+++ b/include/clang/AST/TypeLoc.h
@@ -70,6 +70,28 @@ public:
     return t;
   }
 
+  /// \brief Convert to the specified TypeLoc type, returning a null TypeLoc if
+  /// this TypeLock is not of the desired type. It will consider type
+  /// adjustments from a type that wad written as a T to another type that is
+  /// still canonically a T (ignores parens, attributes, elaborated types, etc).
+  template <typename T>
+  T getAsAdjusted() const {
+    TypeLoc Cur = *this;
+    while (!T::isKind(Cur)) {
+      if (auto PTL = Cur.getAs<ParenTypeLoc>())
+        Cur = PTL.getInnerLoc();
+      else if (auto ATL = Cur.getAs<AttributedTypeLoc>())
+        Cur = ATL.getModifiedLoc();
+      else if (auto ETL = Cur.getAs<ElaboratedTypeLoc>())
+        Cur = ETL.getNamedTypeLoc();
+      else if (auto ATL = Cur.getAs<AdjustedTypeLoc>())
+        Cur = ATL.getOriginalLoc();
+      else
+        break;
+    }
+    return Cur.getAs<T>();
+  }
+
   /// The kinds of TypeLocs.  Equivalent to the Type::TypeClass enum,
   /// except it also defines a Qualified enum that corresponds to the
   /// QualifiedLoc class.

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 5f98d4505f1dd20fc8d22e4506cb0534ceec91e6..bc4611cb067a833b7088e1a8916cbea0db1ae924 100644 (file)
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -7564,11 +7564,12 @@ static FunctionDecl* CreateNewFunctionDecl(Sema &SemaRef, Declarator &D,
     // Determine whether the function was written with a
     // prototype. This true when:
     //   - there is a prototype in the declarator, or
-    //   - the type R of the function is some kind of typedef or other reference
-    //     to a type name (which eventually refers to a function type).
+    //   - the type R of the function is some kind of typedef or other non-
+    //     attributed reference to a type name (which eventually refers to a
+    //     function type).
     bool HasPrototype =
       (D.isFunctionDeclarator() && D.getFunctionTypeInfo().hasPrototype) ||
-      (!isa<FunctionType>(R.getTypePtr()) && R->isFunctionProtoType());
+      (!R->getAsAdjusted<FunctionType>() && R->isFunctionProtoType());
 
     NewFD = FunctionDecl::Create(SemaRef.Context, DC,
                                  D.getLocStart(), NameInfo, R,
@@ -12104,7 +12105,7 @@ Decl *Sema::ActOnFinishFunctionBody(Decl *dcl, Stmt *Body,
           !LangOpts.CPlusPlus) {
         TypeSourceInfo *TI = FD->getTypeSourceInfo();
         TypeLoc TL = TI->getTypeLoc();
-        FunctionTypeLoc FTL = TL.castAs<FunctionTypeLoc>();
+        FunctionTypeLoc FTL = TL.getAsAdjusted<FunctionTypeLoc>();
         Diag(FTL.getLParenLoc(), diag::warn_strict_prototypes) << 1;
       }
     }

diff --git a/test/Sema/knr-def-call.c b/test/Sema/knr-def-call.c
index 80ad0d820b1a11db76faef9df79a64e5b83548e9..ab7e3c9b17f022506e55f53c6c968fe2cdfb49b5 100644 (file)
--- a/test/Sema/knr-def-call.c
+++ b/test/Sema/knr-def-call.c
@@ -39,3 +39,9 @@ void use_proto() {
   proto(42.1); // expected-warning{{implicit conversion from 'double' to 'int' changes value from 42.1 to 42}}
   (&proto)(42.1); // expected-warning{{implicit conversion from 'double' to 'int' changes value from 42.1 to 42}}
 }
+
+// PR31020
+void func(short d) __attribute__((cdecl)); // expected-note{{previous declaration is here}}
+void __attribute__((cdecl)) func(d)
+  short d; // expected-warning{{promoted type 'int' of K&R function parameter is not compatible with the parameter type 'short' declared in a previous prototype}}
+{}

diff --git a/test/Sema/warn-strict-prototypes.c b/test/Sema/warn-strict-prototypes.c
index 496579c1f60e8dea7ae1ff96912a671c80bed1dc..b70f38f9e048a17b00d44b2cd6003f99cb9d8af2 100644 (file)
--- a/test/Sema/warn-strict-prototypes.c
+++ b/test/Sema/warn-strict-prototypes.c
@@ -60,3 +60,8 @@ void foo10(p, p2) void *p; {} // expected-warning {{old-style function definitio
 // K&R function definition with previous prototype declared is not diagnosed.
 void foo11(int p, int p2);
 void foo11(p, p2) int p; int p2; {}
+
+// PR31020
+void __attribute__((cdecl)) foo12(d) // expected-warning {{this old-style function definition is not preceded by a prototype}}
+  short d;
+{}