Add Type::isIncompleteType, which implements the algorithm described in

C99 6.2.5.

llvm-svn: 39289

clang/AST/Type.cpp

@@ -27,6 +27,29 @@ bool Type::isVoidType() const {
   return false;
 }
 
+/// isIncompleteType - Return true if this is an incomplete type (C99 6.2.5p1)
+/// - a type that can describe objects, but which lacks information needed to
+/// determine its size.
+bool Type::isIncompleteType() const {
+  switch (getTypeClass()) {
+  default: return false;
+  case Builtin:
+    // Void is the only incomplete builtin type.  Per C99 6.2.5p19, it can never
+    // be completed.
+    return isVoidType();
+  case Tagged:
+    // A tagged type (struct/union/enum/class) is incomplete if the decl is a
+    // forward declaration, but not a full definition (C99 6.2.5p22).
+    return !cast<TaggedType>(this)->getDecl()->isDefinition();
+    
+  case Array:
+    // An array of unknown size is an incomplete type (C99 6.2.5p22).
+    // FIXME: Implement this.
+    return true; // cast<ArrayType>(this)-> blah.
+  }
+}
+
+
 const char *BuiltinType::getName() const {
   switch (getKind()) {
   default: assert(0 && "Unknown builtin type!");

clang/include/clang/AST/Type.h

@@ -185,6 +185,10 @@ public:
   /// isVoidType - Helper method to determine if this is the 'void' type.
   bool isVoidType() const;
   
+  /// isIncompleteType - Return true if this is an incomplete type (C99 6.2.5p1)
+  /// - a type that can describe objects, but which lacks information needed to
+  /// determine its size (e.g. void, or a fwd declared struct).
+  bool isIncompleteType() const;
   
   virtual void getAsString(std::string &InnerString) const = 0;
   
@@ -256,6 +260,7 @@ private:
   TypeRef ElementType;
   
   /// FIXME: Capture size for VLA or constant size.
+  /// Use this to implement Type::isIncompleteType.
 
   ArrayType(TypeRef et, ArraySizeModifier sm, unsigned tq, Type *can)
     : Type(Array, can), SizeModifier(sm), IndexTypeQuals(tq), ElementType(et) {}