-//===-- 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
#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,
+ GlobalValue(const Type *Ty, ValueTy vty, LinkageTypes linkage,
const std::string &name = "")
- : User(Ty, vty, name), HasInternalLinkage(hasInternalLinkage), Parent(0) {}
+ : Constant(Ty, vty, 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...
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) {
}
};
+} // End llvm namespace
+
#endif