X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FConstant.h;h=faaced8041087703944d5d52eea5384448afd828;hb=5eca075b74d62c621b160aa216b4cd50829a2cc7;hp=c765503736e99a5089629a0cf5e8fa72cc55401b;hpb=13b03586d2911fb6ba324c1fca94c2e2a23444be;p=oota-llvm.git

diff --git a/include/llvm/Constant.h b/include/llvm/Constant.h
index c765503736e..faaced80410 100644
--- a/include/llvm/Constant.h
+++ b/include/llvm/Constant.h
@@ -1,10 +1,10 @@
 //===-- llvm/Constant.h - Constant class definition -------------*- C++ -*-===//
-// 
+//
 //                     The LLVM Compiler Infrastructure
 //
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-// 
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
 //===----------------------------------------------------------------------===//
 //
 // This file contains the declaration of the Constant class.
@@ -17,32 +17,61 @@
 #include "llvm/User.h"
 
 namespace llvm {
+  template<typename T> class SmallVectorImpl;
 
+/// 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:
-  inline Constant(const Type *Ty, ValueTy vty = Value::SimpleConstantVal, 
-                  const std::string& Name = "")
-  : User(Ty, vty, Name) {}
-  ~Constant() {}
+  Constant(const Type *ty, ValueTy vty, Use *Ops, unsigned NumOps)
+    : User(ty, vty, Ops, NumOps) {}
 
   void destroyConstantImpl();
 public:
-  // 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 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.
-  Constant *getOperand(unsigned i) { 
+  Constant *getOperand(unsigned i) {
     return static_cast<Constant*>(User::getOperand(i));
   }
   const Constant *getOperand(unsigned i) const {
@@ -51,6 +80,12 @@ public:
   void setOperand(unsigned i, Constant *C) {
     User::setOperand(i, C);
   }
+  
+  /// getVectorElements - This method, which is only valid on constant of vector
+  /// type, returns the elements of the vector in the specified smallvector.
+  /// This handles breaking down a vector undef into undef elements, etc.  For
+  /// constant exprs and other cases we can't handle, we return an empty vector.
+  void getVectorElements(SmallVectorImpl<Constant*> &Elts) const;
 
   /// 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
@@ -60,16 +95,13 @@ public:
   /// destroyConstantImpl as the last thing they do, to destroy all users and
   /// delete this.
   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 GlobalValue *) { return true; }
   static inline bool classof(const Value *V) {
-    return V->getValueType() == Value::SimpleConstantVal ||
-           V->getValueType() == Value::ConstantExprVal ||
-           V->getValueType() == Value::ConstantAggregateZeroVal ||
-           V->getValueType() == Value::FunctionVal ||
-           V->getValueType() == Value::GlobalVariableVal;
+    return V->getValueID() >= ConstantFirstVal &&
+           V->getValueID() <= ConstantLastVal;
   }
 
   /// replaceUsesOfWithOnConstant - This method is a special form of
@@ -82,8 +114,7 @@ public:
   /// use Value::replaceAllUsesWith, which automatically dispatches to this
   /// method as needed.
   ///
-  virtual void replaceUsesOfWithOnConstant(Value *From, Value *To,
-                                           bool DisableChecking = false) {
+  virtual void replaceUsesOfWithOnConstant(Value *, Value *, Use *) {
     // 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.