Fix stylistic and documentation problems in ValueMap found by Nick Lewycky and

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

diff --git a/include/llvm/Constant.h b/include/llvm/Constant.h
index 2679c107897395c2d0c1b8d34168a1260358adb6..a42c7d43717116b50845870050d7735d4d160ea1 100644 (file)
--- a/include/llvm/Constant.h
+++ b/include/llvm/Constant.h
@@ -17,7 +17,10 @@
 #include "llvm/User.h"
 
 namespace llvm {
+  class APInt;
+
   template<typename T> class SmallVectorImpl;
+  class LLVMContext;
 
 /// 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
@@ -33,43 +36,54 @@ namespace llvm {
 /// 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 
+/// Constants 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)
     : User(ty, vty, Ops, NumOps) {}
 
   void destroyConstantImpl();
 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); }
-  
+  /// isNegativeZeroValue - Return true if the value is what would be returned 
+  /// by getZeroValueForNegation.
+  virtual bool isNegativeZeroValue() const { return isNullValue(); }
+
   /// 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
+  enum PossibleRelocationsTy {
+    NoRelocation = 0,
+    LocalRelocation = 1,
+    GlobalRelocations = 2
+  };
+  
+  /// getRelocationInfo - This method classifies the entry according to
+  /// whether or not it may generate a relocation entry.  This must be
+  /// conservative, so if it might codegen to a relocatable entry, it should say
+  /// so.  The return values are:
+  /// 
+  ///  NoRelocation: This constant pool entry is guaranteed to never have a
+  ///     relocation applied to it (because it holds a simple constant like
+  ///     '4').
+  ///  LocalRelocation: This entry has relocations, but the entries are
+  ///     guaranteed to be resolvable by the static linker, so the dynamic
+  ///     linker will never see them.
+  ///  GlobalRelocations: This entry may have arbitrary relocations.
+  ///
+  /// FIXME: This really should not be in VMCore.
+  PossibleRelocationsTy getRelocationInfo() const;
+  
+  // Specialize get/setOperand for Constants as their operands are always
   // constants as well.
   Constant *getOperand(unsigned i) {
     return static_cast<Constant*>(User::getOperand(i));
@@ -83,8 +97,10 @@ public:
   
   /// 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.
-  void getVectorElements(SmallVectorImpl<Constant*> &Elts) const;
+  /// 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(LLVMContext &Context, 
+                         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
@@ -121,6 +137,17 @@ public:
            "implemented for all constants that have operands!");
     assert(0 && "Constants that do not have operands cannot be using 'From'!");
   }
+  
+  static Constant* getNullValue(const Type* Ty);
+  
+  /// @returns the value for an integer constant of the given type that has all
+  /// its bits set to true.
+  /// @brief Get the all ones value
+  static Constant* getAllOnesValue(const Type* Ty);
+
+  /// getIntegerValue - Return the value for an integer or pointer constant,
+  /// or a vector thereof, with the given scalar value.
+  static Constant* getIntegerValue(const Type* Ty, const APInt &V);
 };
 
 } // End llvm namespace