X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FConstant.h;h=62b75a77fb395a41ead25232165169282cbcde8d;hb=a3af370dc12f6d5100da5d614ab0a62da135569a;hp=bb1b9101c7e17b26bad499d8db74864df959a2e1;hpb=ab267a28239f628e65bef34578695d80ba6d0a9e;p=oota-llvm.git

diff --git a/include/llvm/Constant.h b/include/llvm/Constant.h
index bb1b9101c7e..62b75a77fb3 100644
--- a/include/llvm/Constant.h
+++ b/include/llvm/Constant.h
@@ -18,8 +18,17 @@
 
 namespace llvm {
   template<typename T> class SmallVectorImpl;
+  class LLVMContext;
 
+  /// If object contains references to other objects, then relocations are
+  /// usually required for emission of such object (especially in PIC mode). One
+  /// usually distinguishes local and global relocations. Local relocations are
+  /// made wrt objects in the same module and these objects have local (internal
+  /// or private) linkage. Global relocations are made wrt externally visible
+  /// objects. In most cases local relocations can be resolved via so-called
+  /// 'pre-link' technique.
   namespace Reloc {
+    const unsigned None   = 0;
     const unsigned Local  = 1 << 0; ///< Local relocations are required
     const unsigned Global = 1 << 1; ///< Global relocations are required
     const unsigned LocalOrGlobal = Local | Global;
@@ -45,31 +54,29 @@ namespace llvm {
 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;
 
+  /// 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;
 
   /// ContainsRelocations - Return true if the constant value contains
-  /// relocations which cannot be resolved at compile time.
+  /// relocations which cannot be resolved at compile time. Note that answer is
+  /// not exclusive: there can be possibility that relocations of other kind are
+  /// required as well.
   bool ContainsRelocations(unsigned Kind = Reloc::LocalOrGlobal) const;
 
   // Specialize get/setOperand for Constants as their operands are always
@@ -88,7 +95,8 @@ public:
   /// 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;
+  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