Devirtualizing Value destructor (PR889). Patch by Pawel Kunio!

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

diff --git a/include/llvm/Constant.h b/include/llvm/Constant.h
index e2b77a7e21a98788138d99c09f2792b6b488cce1..e48a9c5d74078fc457c25d1d26b1a1ec307c06ea 100644 (file)
--- a/include/llvm/Constant.h
+++ b/include/llvm/Constant.h
@@ -18,25 +18,59 @@
 
 namespace llvm {
 
+/// This is an important base class in LLVM. It provides the common facilities
+/// of all constant values in an LLVM program. A constant is a value that is
+/// immutable at runtime. Functions are constants because their address is
+/// immutable. Same with global variables. 
+/// 
+/// All constants share the capabilities provided in this class. All constants
+/// can have a null value. They can have an operand list. Constants can be
+/// simple (integer and floating point values), complex (arrays and structures),
+/// or expression based (computations yielding a constant value composed of 
+/// only certain operators and other constant values).
+/// 
+/// Note that Constants are immutable (once created they never change) 
+/// and are fully shared by structural equivalence.  This means that two 
+/// structurally equivalent constants will always have the same address.  
+/// Constant's are created on demand as needed and never deleted: thus clients 
+/// don't have to worry about the lifetime of the objects.
+/// @brief LLVM Constant Representation
 class Constant : public User {
   void operator=(const Constant &);     // Do not implement
   Constant(const Constant &);           // Do not implement
 protected:
-  Constant(const Type *Ty, ValueTy vty, Use *Ops, unsigned NumOps,
-           const std::string& Name = "")
-    : User(Ty, vty, Ops, NumOps, Name) {}
+  Constant(const Type *Ty, ValueTy vty, Use *Ops, unsigned NumOps)
+    : User(Ty, vty, Ops, NumOps) {}
 
   void destroyConstantImpl();
+  static void destroyThis(Constant*v) {
+    User::destroyThis(v);
+  }
+  friend class Value;
 public:
   /// Static constructor to get a '0' constant of arbitrary type...
   ///
   static Constant *getNullValue(const Type *Ty);
 
+  /// Static constructor to get a '-1' constant.  This supports integers and
+  /// vectors.
+  ///
+  static Constant *getAllOnesValue(const Type *Ty);
+  
   /// 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;
+  void print(std::ostream *O) const { if (O) print(*O); }
+  
+  /// canTrap - Return true if evaluation of this constant could trap.  This is
+  /// true for things like constant expressions that could divide by zero.
+  bool canTrap() const;
+
+  /// ContaintsRelocations - Return true if the constant value contains
+  /// relocations which cannot be resolved at compile time.
+  bool ContainsRelocations() const;
 
   // Specialize get/setOperand for Constant's as their operands are always
   // constants as well.
@@ -63,8 +97,8 @@ public:
   static inline bool classof(const Constant *) { return true; }
   static inline bool classof(const GlobalValue *) { return true; }
   static inline bool classof(const Value *V) {
-    return V->getValueType() >= ConstantFirstVal &&
-           V->getValueType() <= ConstantLastVal;
+    return V->getValueID() >= ConstantFirstVal &&
+           V->getValueID() <= ConstantLastVal;
   }
 
   /// replaceUsesOfWithOnConstant - This method is a special form of
@@ -86,10 +120,12 @@ public:
     assert(0 && "Constants that do not have operands cannot be using 'From'!");
   }
 
-  /// clearAllValueMaps - This method frees all internal memory used by the
-  /// constant subsystem, which can be used in environments where this memory
-  /// is otherwise reported as a leak.
-  static void clearAllValueMaps();
+  /// getStringValue - Turn an LLVM constant pointer that eventually points to a
+  /// global into a string value.  Return an empty string if we can't do it.
+  /// Parameter Chop determines if the result is chopped at the first null
+  /// terminator.
+  ///
+  std::string getStringValue(bool Chop = true, unsigned Offset = 0);
 };
 
 } // End llvm namespace