Permit the IntPtrTy argument to isEliminableCastPair to be null,

[oota-llvm.git] / include / llvm / Value.h

diff --git a/include/llvm/Value.h b/include/llvm/Value.h
index 3600a5cef31e259688648221d1f50f0d8d546c35..7e7b415ffdeed671b1ba2ec26cf13a283633a236 100644 (file)
--- a/include/llvm/Value.h
+++ b/include/llvm/Value.h
@@ -34,9 +34,12 @@ class InlineAsm;
 class ValueSymbolTable;
 class TypeSymbolTable;
 template<typename ValueTy> class StringMapEntry;
+template <typename ValueTy = Value>
+class AssertingVH;
 typedef StringMapEntry<Value*> ValueName;
 class raw_ostream;
 class AssemblyAnnotationWriter;
+class ValueHandleBase;
 
 //===----------------------------------------------------------------------===//
 //                                 Value Class
@@ -50,11 +53,21 @@ class AssemblyAnnotationWriter;
 /// automatically updates the module's symbol table.
 ///
 /// Every value has a "use list" that keeps track of which other Values are
-/// using this Value.
+/// using this Value.  A Value can also have an arbitrary number of ValueHandle
+/// objects that watch it and listen to RAUW and Destroy events see
+/// llvm/Support/ValueHandle.h for details.
+///
 /// @brief LLVM Value Representation
 class Value {
   const unsigned char SubclassID;   // Subclass identifier (for isa/dyn_cast)
+  unsigned char HasValueHandle : 1; // Has a ValueHandle pointing to this?
 protected:
+  /// SubclassOptionalData - This member is similar to SubclassData, however it
+  /// is for holding information which may be used to aid optimization, but
+  /// which may be cleared to zero without affecting conservative
+  /// interpretation.
+  unsigned char SubclassOptionalData : 7;
+
   /// SubclassData - This member is defined by this class, but is not used for
   /// anything.  Subclasses can use it to hold whatever state they find useful.
   /// This field is initialized to zero by the ctor.
@@ -65,6 +78,7 @@ private:
 
   friend class ValueSymbolTable; // Allow ValueSymbolTable to directly mod Name.
   friend class SymbolTable;      // Allow SymbolTable to directly poke Name.
+  friend class ValueHandleBase;
   ValueName *Name;
 
   void operator=(const Value &);     // Do not implement
@@ -132,6 +146,12 @@ public:
   // Only use when in type resolution situations!
   void uncheckedReplaceAllUsesWith(Value *V);
 
+  /// clearOptionalData - Clear any optional optimization data from this Value.
+  /// Transformation passes must call this method whenever changing the IR
+  /// in a way that would affect the values produced by this Value, unless
+  /// it takes special care to ensure correctness in some other way.
+  void clearOptionalData() { SubclassOptionalData = 0; }
+
   //----------------------------------------------------------------------
   // Methods for handling the chain of uses of this Value.
   //
@@ -195,13 +215,15 @@ public:
     ConstantStructVal,        // This is an instance of ConstantStruct
     ConstantVectorVal,        // This is an instance of ConstantVector
     ConstantPointerNullVal,   // This is an instance of ConstantPointerNull
+    MDStringVal,              // This is an instance of MDString
+    MDNodeVal,                // This is an instance of MDNode
     InlineAsmVal,             // This is an instance of InlineAsm
     PseudoSourceValueVal,     // This is an instance of PseudoSourceValue
     InstructionVal,           // This is an instance of Instruction
     
     // Markers:
     ConstantFirstVal = FunctionVal,
-    ConstantLastVal  = ConstantPointerNullVal
+    ConstantLastVal  = MDNodeVal
   };
 
   /// getValueID - Return an ID for the concrete type of this object.  This is