Adjust to changes in the User class.

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

diff --git a/include/llvm/GlobalValue.h b/include/llvm/GlobalValue.h
index af2ff23c82edfedc56fbea6dcb7dc02e0d0a059c..60176c588d37a4fd66d6cbecb935f1b3f7a28afe 100644 (file)
--- a/include/llvm/GlobalValue.h
+++ b/include/llvm/GlobalValue.h
@@ -1,4 +1,11 @@
-//===-- llvm/GlobalValue.h - Class to represent a global value ---*- C++ -*--=//
+//===-- llvm/GlobalValue.h - Class to represent a global value --*- 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 a common base class of all globally definable objects.  As such,
 // it is subclassed by GlobalVariable and by Function.  This is used because you
@@ -10,31 +17,69 @@
 #ifndef LLVM_GLOBALVALUE_H
 #define LLVM_GLOBALVALUE_H
 
-#include "llvm/User.h"
+#include "llvm/Constant.h"
+
+namespace llvm {
+
 class PointerType;
 class Module;
 
-class GlobalValue : public User {
+class GlobalValue : public Constant {
   GlobalValue(const GlobalValue &);             // do not implement
+public:
+  enum LinkageTypes {
+    ExternalLinkage,   // Externally visible function
+    LinkOnceLinkage,   // Keep one copy of named function when linking (inline)
+    WeakLinkage,       // Keep one copy of named function when linking (weak)
+    AppendingLinkage,  // Special purpose, only applies to global arrays
+    InternalLinkage,   // Rename collisions when linking (static functions)
+    GhostLinkage       // Stand-in functions for streaming fns from BC files
+  };
 protected:
-  GlobalValue(const Type *Ty, ValueTy vty, bool hasInternalLinkage,
-             const std::string &name = "")
-    : User(Ty, vty, name), HasInternalLinkage(hasInternalLinkage), Parent(0) {}
+  GlobalValue(const Type *Ty, ValueTy vty, Use *Ops, unsigned NumOps,
+              LinkageTypes linkage, const std::string &name = "")
+    : Constant(Ty, vty, Ops, NumOps, name), Linkage(linkage), Parent(0) { }
 
-  bool HasInternalLinkage;    // Is this value accessable externally?
+  LinkageTypes Linkage;   // The linkage of this global
   Module *Parent;
 public:
-  ~GlobalValue() {}
+  ~GlobalValue() {
+    removeDeadConstantUsers();   // remove any dead constants using this.
+  }
+
+  /// If the usage is empty (except transitively dead constants), then this
+  /// global value can can be safely deleted since the destructor will 
+  /// delete the dead constants as well.
+  /// @brief Determine if the usage of this global value is empty except 
+  /// for transitively dead constants.
+  bool use_empty_except_constants();
 
   /// getType - Global values are always pointers.
   inline const PointerType *getType() const {
-    return (const PointerType*)User::getType();
+    return reinterpret_cast<const PointerType*>(User::getType());
   }
 
-  /// Internal Linkage - True if the global value is inaccessible to 
-  bool hasInternalLinkage() const { return HasInternalLinkage; }
-  bool hasExternalLinkage() const { return !HasInternalLinkage; }
-  void setInternalLinkage(bool HIL) { HasInternalLinkage = HIL; }
+  bool hasExternalLinkage()  const { return Linkage == ExternalLinkage; }
+  bool hasLinkOnceLinkage()  const { return Linkage == LinkOnceLinkage; }
+  bool hasWeakLinkage()      const { return Linkage == WeakLinkage; }
+  bool hasAppendingLinkage() const { return Linkage == AppendingLinkage; }
+  bool hasInternalLinkage()  const { return Linkage == InternalLinkage; }
+  void setLinkage(LinkageTypes LT) { Linkage = LT; }
+  LinkageTypes getLinkage() const { return Linkage; }
+
+  /// hasNotBeenReadFromBytecode - If a module provider is being used to lazily
+  /// stream in functions from disk, this method can be used to check to see if
+  /// the function has been read in yet or not.  Unless you are working on the
+  /// JIT or something else that streams stuff in lazily, you don't need to
+  /// worry about this.
+  bool hasNotBeenReadFromBytecode() const { return Linkage == GhostLinkage; }
+
+  /// Override from Constant class. No GlobalValue's are null values so this
+  /// always returns false.
+  virtual bool isNullValue() const { return false; }
+
+  /// Override from Constant class.
+  virtual void destroyConstant();
 
   /// isExternal - Return true if the primary definition of this global value is
   /// outside of the current translation unit...
@@ -45,6 +90,16 @@ public:
   inline Module *getParent() { return Parent; }
   inline const Module *getParent() const { return Parent; }
 
+  /// removeDeadConstantUsers - If there are any dead constant users dangling
+  /// off of this global value, remove them.  This method is useful for clients
+  /// that want to check to see if a global is unused, but don't want to deal
+  /// with potentially dead constants hanging off of the globals.
+  ///
+  /// This method tries to make the global dead.  If it detects a user that
+  /// would prevent it from becoming completely dead, it gives up early,
+  /// potentially leaving some dead constant users around.
+  void removeDeadConstantUsers();
+
   // Methods for support type inquiry through isa, cast, and dyn_cast:
   static inline bool classof(const GlobalValue *T) { return true; }
   static inline bool classof(const Value *V) {
@@ -53,4 +108,6 @@ public:
   }
 };
 
+} // End llvm namespace
+
 #endif