Rename TarjanSCCIterator -> scc_iterator

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

diff --git a/include/llvm/Constant.h b/include/llvm/Constant.h
index 572d1d15ca92761ed20796f9796a8585c2f43e9f..e6f63b12921b9d6438f91bad7032711ae7dad1e6 100644 (file)
--- a/include/llvm/Constant.h
+++ b/include/llvm/Constant.h
@@ -14,34 +14,74 @@ protected:
   inline Constant(const Type *Ty) : User(Ty, Value::ConstantVal) {}
   ~Constant() {}
 
-  // destroyConstant - Called if some element of this constant is no longer
-  // valid.  At this point only other constants may be on the use_list for this
-  // constant.  Any constants on our Use list must also be destroy'd.  The
-  // implementation must be sure to remove the constant from the list of
-  // available cached constants.  Implementations should call
-  // destroyConstantImpl as the last thing they do, to destroy all users and
-  // delete this.
-  //
-  virtual void destroyConstant() { assert(0 && "Not reached!"); }
   void destroyConstantImpl();
 public:
-  // Specialize setName to handle symbol table majik...
+  // setName - Specialize setName to handle symbol table majik...
   virtual void setName(const std::string &name, SymbolTable *ST = 0);
 
-  // Static constructor to get a '0' constant of arbitrary type...
+  /// Static constructor to get a '0' constant of arbitrary type...
+  ///
   static Constant *getNullValue(const Type *Ty);
 
-  // isNullValue - Return true if this is the value that would be returned by
-  // getNullValue.
+  /// isNullValue - Return true if this is the value that would be returned by
+  /// getNullValue.
   virtual bool isNullValue() const = 0;
 
   virtual void print(std::ostream &O) const;
 
-  // Methods for support type inquiry through isa, cast, and dyn_cast:
+  /// isConstantExpr - Return true if this is a ConstantExpr
+  ///
+  virtual bool isConstantExpr() const { return false; }
+
+
+  /// destroyConstant - Called if some element of this constant is no longer
+  /// valid.  At this point only other constants may be on the use_list for this
+  /// constant.  Any constants on our Use list must also be destroy'd.  The
+  /// implementation must be sure to remove the constant from the list of
+  /// available cached constants.  Implementations should call
+  /// destroyConstantImpl as the last thing they do, to destroy all users and
+  /// delete this.
+  ///
+  /// Note that this call is only valid on non-primitive constants: You cannot
+  /// destroy an integer constant for example.  This API is used to delete
+  /// constants that have ConstantPointerRef's embeded in them when the module
+  /// is deleted, and it is used by GlobalDCE to remove ConstantPointerRefs that
+  /// are unneeded, allowing globals to be DCE'd.
+  ///
+  virtual void destroyConstant() { assert(0 && "Not reached!"); }
+
+  
+  //// Methods for support type inquiry through isa, cast, and dyn_cast:
   static inline bool classof(const Constant *) { return true; }
   static inline bool classof(const Value *V) {
     return V->getValueType() == Value::ConstantVal;
   }
+
+  /// replaceUsesOfWithOnConstant - This method is a special form of
+  /// User::replaceUsesOfWith (which does not work on constants) that does work
+  /// on constants.  Basically this method goes through the trouble of building
+  /// a new constant that is equivalent to the current one, with all uses of
+  /// From replaced with uses of To.  After this construction is completed, all
+  /// of the users of 'this' are replaced to use the new constant, and then
+  /// 'this' is deleted.  In general, you should not call this method, instead,
+  /// use Value::replaceAllUsesWith, which automatically dispatches to this
+  /// method as needed.
+  ///
+  virtual void replaceUsesOfWithOnConstant(Value *From, Value *To,
+                                           bool DisableChecking = false) {
+    // Provide a default implementation for constants (like integers) that
+    // cannot use any other values.  This cannot be called at runtime, but needs
+    // to be here to avoid link errors.
+    assert(getNumOperands() == 0 && "replaceUsesOfWithOnConstant must be "
+           "implemented for all constants that have operands!");
+    assert(0 && "Constants that do not have operands cannot be using 'From'!");
+  }
+
+  // WARNING: Only to be used by Bytecode & Assembly Parsers!  USER CODE SHOULD
+  // NOT USE THIS!!
+  // Returns the number of uses of OldV that were replaced.
+  unsigned mutateReferences(Value* OldV, Value *NewV);
+  // END WARNING!!
 };
 
 #endif