+++ /dev/null
-//===-- llvm/GlobalVariable.h - GlobalVariable class ------------*- C++ -*-===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file 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 initial 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/ADT/Twine.h"
-#include "llvm/ADT/ilist_node.h"
-#include "llvm/GlobalValue.h"
-#include "llvm/OperandTraits.h"
-
-namespace llvm {
-
-class Module;
-class Constant;
-template<typename ValueSubClass, typename ItemParentClass>
- class SymbolTableListTraits;
-
-class GlobalVariable : public GlobalValue, public ilist_node<GlobalVariable> {
- friend class SymbolTableListTraits<GlobalVariable, Module>;
- void *operator new(size_t, unsigned) LLVM_DELETED_FUNCTION;
- void operator=(const GlobalVariable &) LLVM_DELETED_FUNCTION;
- GlobalVariable(const GlobalVariable &) LLVM_DELETED_FUNCTION;
-
- void setParent(Module *parent);
-
- bool isConstantGlobal : 1; // Is this a global constant?
- unsigned threadLocalMode : 3; // Is this symbol "Thread Local",
- // if so, what is the desired model?
-
-public:
- // allocate space for exactly one operand
- void *operator new(size_t s) {
- return User::operator new(s, 1);
- }
-
- enum ThreadLocalMode {
- NotThreadLocal = 0,
- GeneralDynamicTLSModel,
- LocalDynamicTLSModel,
- InitialExecTLSModel,
- LocalExecTLSModel
- };
-
- /// GlobalVariable ctor - If a parent module is specified, the global is
- /// automatically inserted into the end of the specified modules global list.
- GlobalVariable(Type *Ty, bool isConstant, LinkageTypes Linkage,
- Constant *Initializer = 0, const Twine &Name = "",
- ThreadLocalMode = NotThreadLocal, unsigned AddressSpace = 0);
- /// GlobalVariable ctor - This creates a global and inserts it before the
- /// specified other global.
- GlobalVariable(Module &M, Type *Ty, bool isConstant,
- LinkageTypes Linkage, Constant *Initializer,
- const Twine &Name = "",
- GlobalVariable *InsertBefore = 0,
- ThreadLocalMode = NotThreadLocal,
- unsigned AddressSpace = 0);
-
- ~GlobalVariable() {
- NumOperands = 1; // FIXME: needed by operator delete
- }
-
- /// Provide fast operand accessors
- DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
-
- /// 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(); }
-
- /// hasDefinitiveInitializer - Whether the global variable has an initializer,
- /// and any other instances of the global (this can happen due to weak
- /// linkage) are guaranteed to have the same initializer.
- ///
- /// Note that if you want to transform a global, you must use
- /// hasUniqueInitializer() instead, because of the *_odr linkage type.
- ///
- /// Example:
- ///
- /// @a = global SomeType* null - Initializer is both definitive and unique.
- ///
- /// @b = global weak SomeType* null - Initializer is neither definitive nor
- /// unique.
- ///
- /// @c = global weak_odr SomeType* null - Initializer is definitive, but not
- /// unique.
- inline bool hasDefinitiveInitializer() const {
- return hasInitializer() &&
- // The initializer of a global variable with weak linkage may change at
- // link time.
- !mayBeOverridden();
- }
-
- /// hasUniqueInitializer - Whether the global variable has an initializer, and
- /// any changes made to the initializer will turn up in the final executable.
- inline bool hasUniqueInitializer() const {
- return hasInitializer() &&
- // It's not safe to modify initializers of global variables with weak
- // linkage, because the linker might choose to discard the initializer and
- // use the initializer from another instance of the global variable
- // instead. It is wrong to modify the initializer of a global variable
- // with *_odr linkage because then different instances of the global may
- // have different initializers, breaking the One Definition Rule.
- !isWeakForLinker();
- }
-
- /// 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 const Constant *getInitializer() const {
- assert(hasInitializer() && "GV doesn't have initializer!");
- return static_cast<Constant*>(Op<0>().get());
- }
- inline Constant *getInitializer() {
- assert(hasInitializer() && "GV doesn't have initializer!");
- return static_cast<Constant*>(Op<0>().get());
- }
- /// setInitializer - Sets the initializer for this global variable, removing
- /// any existing initializer if InitVal==NULL. If this GV has type T*, the
- /// initializer must have type T.
- void setInitializer(Constant *InitVal);
-
- /// 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 Val) { isConstantGlobal = Val; }
-
- /// If the value is "Thread Local", its value isn't shared by the threads.
- bool isThreadLocal() const { return threadLocalMode != NotThreadLocal; }
- void setThreadLocal(bool Val) {
- threadLocalMode = Val ? GeneralDynamicTLSModel : NotThreadLocal;
- }
- void setThreadLocalMode(ThreadLocalMode Val) { threadLocalMode = Val; }
- ThreadLocalMode getThreadLocalMode() const {
- return static_cast<ThreadLocalMode>(threadLocalMode);
- }
-
- /// copyAttributesFrom - copy all additional attributes (those not needed to
- /// create a GlobalVariable) from the GlobalVariable Src to this one.
- void copyAttributesFrom(const GlobalValue *Src);
-
- /// removeFromParent - This method unlinks 'this' from the containing module,
- /// but does not delete it.
- ///
- virtual void removeFromParent();
-
- /// eraseFromParent - This method unlinks 'this' from the containing module
- /// and deletes it.
- ///
- virtual void eraseFromParent();
-
- /// Override Constant's implementation of this method so we can
- /// replace constant initializers.
- virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U);
-
- // Methods for support type inquiry through isa, cast, and dyn_cast:
- static inline bool classof(const Value *V) {
- return V->getValueID() == Value::GlobalVariableVal;
- }
-};
-
-template <>
-struct OperandTraits<GlobalVariable> :
- public OptionalOperandTraits<GlobalVariable> {
-};
-
-DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GlobalVariable, Value)
-
-} // End llvm namespace
-
-#endif
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