llvm-6502/include/llvm/GlobalVariable.h
2003-06-30 21:59:07 +00:00

102 lines
3.9 KiB
C++

//===-- llvm/Global.h - Class to represent a global variable -----*- C++ -*--=//
//
// 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"
class Module;
class Constant;
class PointerType;
template<typename SC> struct ilist_traits;
template<typename ValueSubClass, typename ItemParentClass, typename SymTabClass,
typename SubClass> class SymbolTableListTraits;
class GlobalVariable : public GlobalValue {
friend class SymbolTableListTraits<GlobalVariable, Module, Module,
ilist_traits<GlobalVariable> >;
void setParent(Module *parent);
GlobalVariable *Prev, *Next;
void setNext(GlobalVariable *N) { Next = N; }
void setPrev(GlobalVariable *N) { Prev = N; }
bool isConstantGlobal; // Is this a global constant?
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);
// Specialize setName to handle symbol table majik...
virtual void setName(const std::string &name, SymbolTable *ST = 0);
/// isExternal - Is this global variable lacking an initializer? If so, the
/// global variable is defined in some other translation unit, and is thus
/// externally defined here.
///
virtual bool isExternal() const { return Operands.empty(); }
/// hasInitializer - Unless a global variable isExternal(), it has an
/// initializer. The initializer for the global variable/constant is held by
/// Operands[0] if an initializer is specified.
///
inline bool hasInitializer() const { return !isExternal(); }
/// 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 (Constant*)Operands[0].get();
}
inline Constant *getInitializer() {
assert(hasInitializer() && "GV doesn't have initializer!");
return (Constant*)Operands[0].get();
}
inline void setInitializer(Constant *CPV) {
if (CPV == 0) {
if (hasInitializer()) Operands.pop_back();
} else {
if (!hasInitializer()) Operands.push_back(Use(0, this));
Operands[0] = (Value*)CPV;
}
}
// 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; }
/// 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; }
virtual void print(std::ostream &OS) const;
// 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->getValueType() == Value::GlobalVariableVal;
}
};
#endif