From 42a695c2f2627a04b1fc8e2160d608c39f1dd6ac Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Mon, 8 Apr 2002 21:51:32 +0000
Subject: [PATCH] * Move casting stuff out to Support/Casting.h * Add top level
 virtual print function, disallows instantiating Value's   directly. * Provide
 operator<< for values here, instead of in Assembly/Writer.h

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2168 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Value.h | 88 ++++++++------------------------------------
 1 file changed, 16 insertions(+), 72 deletions(-)

diff --git a/include/llvm/Value.h b/include/llvm/Value.h
index ce822fe7958..7ffcf1b7507 100644
--- a/include/llvm/Value.h
+++ b/include/llvm/Value.h
@@ -6,8 +6,6 @@
 //
 // This file also defines the Use<> template for users of value.
 //
-// This file also defines the isa<X>(), cast<X>(), and dyn_cast<X>() templates.
-//
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_VALUE_H
@@ -16,6 +14,7 @@
 #include <vector>
 #include "llvm/Annotation.h"
 #include "llvm/AbstractTypeUser.h"
+#include "Support/Casting.h"
 
 class User;
 class Type;
@@ -25,7 +24,6 @@ class Instruction;
 class BasicBlock;
 class GlobalValue;
 class Function;
-typedef Function Method;
 class GlobalVariable;
 class Module;
 class SymbolTable;
@@ -65,6 +63,9 @@ public:
   
   // Support for debugging 
   void dump() const;
+
+  // Implement operator<< on Value...
+  virtual void print(std::ostream &O) const = 0;
   
   // All values can potentially be typed
   inline const Type *getType() const { return Ty; }
@@ -122,6 +123,14 @@ public:
   void killUse(User *I);
 };
 
+inline std::ostream &operator<<(std::ostream &OS, const Value *V) {
+  if (V == 0)
+    OS << "<null> value!\n";
+  else
+    V->print(OS);
+  return OS;
+}
+
 
 //===----------------------------------------------------------------------===//
 //                                 UseTy Class
@@ -172,79 +181,14 @@ public:
 
 typedef UseTy<Value> Use;    // Provide Use as a common UseTy type
 
-// real_type - Provide a macro to get the real type of a value that might be 
-// a use.  This provides a typedef 'Type' that is the argument type for all
-// non UseTy types, and is the contained pointer type of the use if it is a
-// UseTy.
+// Provide a specialization of real_type to work with use's... to make them a
+// bit more transparent.
 //
-template <class X> class real_type { typedef X Type; };
 template <class X> class real_type <class UseTy<X> > { typedef X *Type; };
 
-//===----------------------------------------------------------------------===//
-//                          Type Checking Templates
-//===----------------------------------------------------------------------===//
 
-// isa<X> - Return true if the parameter to the template is an instance of the
-// template type argument.  Used like this:
-//
-//  if (isa<Type>(myVal)) { ... }
-//
-template <class X, class Y>
-inline bool isa(Y Val) {
-  assert(Val && "isa<Ty>(NULL) invoked!");
-  return X::classof(Val);
-}
-
-
-// cast<X> - Return the argument parameter cast to the specified type.  This
-// casting operator asserts that the type is correct, so it does not return null
-// on failure.  But it will correctly return NULL when the input is NULL.
-// Used Like this:
-//
-//  cast<      Instruction>(myVal)->getParent()
-//  cast<const Instruction>(myVal)->getParent()
-//
-template <class X, class Y>
-inline X *cast(Y Val) {
-  assert(isa<X>(Val) && "cast<Ty>() argument of uncompatible type!");
-  return (X*)(real_type<Y>::Type)Val;
-}
-
-// cast_or_null<X> - Functionally identical to cast, except that a null value is
-// accepted.
-//
-template <class X, class Y>
-inline X *cast_or_null(Y Val) {
-  assert((Val == 0 || isa<X>(Val)) &&
-         "cast_or_null<Ty>() argument of uncompatible type!");
-  return (X*)(real_type<Y>::Type)Val;
-}
-
-
-// dyn_cast<X> - Return the argument parameter cast to the specified type.  This
-// casting operator returns null if the argument is of the wrong type, so it can
-// be used to test for a type as well as cast if successful.  This should be
-// used in the context of an if statement like this:
-//
-//  if (const Instruction *I = dyn_cast<const Instruction>(myVal)) { ... }
-//
-
-template <class X, class Y>
-inline X *dyn_cast(Y Val) {
-  return isa<X>(Val) ? cast<X>(Val) : 0;
-}
-
-// dyn_cast_or_null<X> - Functionally identical to dyn_cast, except that a null
-// value is accepted.
-//
-template <class X, class Y>
-inline X *dyn_cast_or_null(Y Val) {
-  return (Val && isa<X>(Val)) ? cast<X>(Val) : 0;
-}
-
-
-// isa - Provide some specializations of isa so that we have to include the
-// subtype header files to test to see if the value is a subclass...
+// isa - Provide some specializations of isa so that we don't have to include
+// the subtype header files to test to see if the value is a subclass...
 //
 template <> inline bool isa<Type, const Value*>(const Value *Val) { 
   return Val->getValueType() == Value::TypeVal;