Implement a constant pointer value

llvm-svn: 667

include/llvm/ConstPoolVals.h

@@ -13,6 +13,7 @@
 
 class ArrayType;
 class StructType;
+class PointerType;
 
 //===----------------------------------------------------------------------===//
 //                            ConstPoolVal Class
@@ -182,4 +183,24 @@ public:
   inline const vector<Use> &getValues() const { return Operands; }
 };
 
+//===---------------------------------------------------------------------------
+// ConstPoolPointer - Constant Pointer Declarations
+//
+// The ConstPoolPointer class represents a null pointer of a specific type. For
+// a more specific/useful instance, a subclass of ConstPoolPointer should be
+// used.
+//
+class ConstPoolPointer : public ConstPoolVal {
+  ConstPoolPointer(const ConstPoolPointer &);      // DO NOT IMPLEMENT
+protected:
+  ConstPoolPointer(const PointerType *T);
+  ~ConstPoolPointer() {}
+public:
+  static ConstPoolPointer *getNullPointer(const PointerType *T) {
+    return new ConstPoolPointer(T);
+  }
+
+  virtual string getStrValue() const;
+};
+
 #endif

lib/VMCore/ConstPoolVals.cpp

@@ -43,6 +43,9 @@ ConstPoolVal *ConstPoolVal::getNullConstant(const Type *Ty) {
 
   case Type::FloatTyID:
   case Type::DoubleTyID: return ConstPoolFP::get(Ty, 0);
+
+  case Type::PointerTyID: 
+    return ConstPoolPointer::getNullPointer(Ty->castPointerType());
   default:
     return 0;
   }
@@ -98,6 +101,8 @@ ConstPoolStruct::ConstPoolStruct(const StructType *T,
   }
 }
 
+ConstPoolPointer::ConstPoolPointer(const PointerType *T) : ConstPoolVal(T) {}
+
 
 //===----------------------------------------------------------------------===//
 //                          getStrValue implementations
@@ -144,6 +149,10 @@ string ConstPoolStruct::getStrValue() const {
   return Result + " }";
 }
 
+string ConstPoolPointer::getStrValue() const {
+  return "null";
+}
+
 //===----------------------------------------------------------------------===//
 //                      isValueValidForType implementations