//===-- llvm/GlobalVariable.h - GlobalVariable class ------------*- 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 contains the declaration of the GlobalVariable class, which // represents a single global variable (or constant) in the VM. // // Global variables are constant pointers that refer to hunks of space that are // allocated by either the VM, or by the linker in a static compiler. A global // variable may have an intial value, which is copied into the executables .data // area. Global Constants are required to have initializers. // //===----------------------------------------------------------------------===// #ifndef LLVM_GLOBAL_VARIABLE_H #define LLVM_GLOBAL_VARIABLE_H #include "llvm/GlobalValue.h" namespace llvm { class Module; class Constant; class PointerType; template<typename ValueSubClass, typename ItemParentClass> class SymbolTableListTraits; class GlobalVariable : public GlobalValue { friend class SymbolTableListTraits<GlobalVariable, Module>; void operator=(const GlobalVariable &); // Do not implement GlobalVariable(const GlobalVariable &); // Do not implement void setParent(Module *parent); GlobalVariable *Prev, *Next; void setNext(GlobalVariable *N) { Next = N; } void setPrev(GlobalVariable *N) { Prev = N; } bool isConstantGlobal : 1; // Is this a global constant? bool isThreadLocalSymbol : 1; // Is this symbol "Thread Local"? Use Initializer; public: /// GlobalVariable ctor - If a parent module is specified, the global is /// automatically inserted into the end of the specified modules global list. GlobalVariable(const Type *Ty, bool isConstant, LinkageTypes Linkage, Constant *Initializer = 0, const std::string &Name = "", Module *Parent = 0, bool ThreadLocal = false); /// GlobalVariable ctor - This creates a global and inserts it before the /// specified other global. GlobalVariable(const Type *Ty, bool isConstant, LinkageTypes Linkage, Constant *Initializer, const std::string &Name, GlobalVariable *InsertBefore, bool ThreadLocal = false); /// isDeclaration - Is this global variable lacking an initializer? If so, /// the global variable is defined in some other translation unit, and is thus /// only a declaration here. virtual bool isDeclaration() const { return getNumOperands() == 0; } /// hasInitializer - Unless a global variable isExternal(), it has an /// initializer. The initializer for the global variable/constant is held by /// Initializer if an initializer is specified. /// inline bool hasInitializer() const { return !isDeclaration(); } /// getInitializer - Return the initializer for this global variable. It is /// illegal to call this method if the global is external, because we cannot /// tell what the value is initialized to! /// inline Constant *getInitializer() const { assert(hasInitializer() && "GV doesn't have initializer!"); return reinterpret_cast<Constant*>(Initializer.get()); } inline Constant *getInitializer() { assert(hasInitializer() && "GV doesn't have initializer!"); return reinterpret_cast<Constant*>(Initializer.get()); } inline void setInitializer(Constant *CPV) { if (CPV == 0) { if (hasInitializer()) { Initializer.set(0); NumOperands = 0; } } else { if (!hasInitializer()) NumOperands = 1; Initializer.set(CPV); } } /// If the value is a global constant, its value is immutable throughout the /// runtime execution of the program. Assigning a value into the constant /// leads to undefined behavior. /// bool isConstant() const { return isConstantGlobal; } void setConstant(bool Value) { isConstantGlobal = Value; } /// If the value is "Thread Local", its value isn't shared by the threads. bool isThreadLocal() const { return isThreadLocalSymbol; } void setThreadLocal(bool Value) { isThreadLocalSymbol = Value; } /// removeFromParent - This method unlinks 'this' from the containing module, /// but does not delete it. /// void removeFromParent(); /// eraseFromParent - This method unlinks 'this' from the containing module /// and deletes it. /// void eraseFromParent(); /// Override Constant's implementation of this method so we can /// replace constant initializers. virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U); virtual void print(std::ostream &OS) const; void print(std::ostream *OS) const { if (OS) print(*OS); } // Methods for support type inquiry through isa, cast, and dyn_cast: static inline bool classof(const GlobalVariable *) { return true; } static inline bool classof(const Value *V) { return V->getValueID() == Value::GlobalVariableVal; } private: // getNext/Prev - Return the next or previous global variable in the list. GlobalVariable *getNext() { return Next; } const GlobalVariable *getNext() const { return Next; } GlobalVariable *getPrev() { return Prev; } const GlobalVariable *getPrev() const { return Prev; } }; } // End llvm namespace #endif