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Diffstat (limited to 'contrib/llvm/include/llvm/IR/GlobalVariable.h')
| -rw-r--r-- | contrib/llvm/include/llvm/IR/GlobalVariable.h | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/contrib/llvm/include/llvm/IR/GlobalVariable.h b/contrib/llvm/include/llvm/IR/GlobalVariable.h new file mode 100644 index 0000000..bfed507 --- /dev/null +++ b/contrib/llvm/include/llvm/IR/GlobalVariable.h @@ -0,0 +1,210 @@ +//===-- 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_IR_GLOBALVARIABLE_H +#define LLVM_IR_GLOBALVARIABLE_H + +#include "llvm/ADT/Twine.h" +#include "llvm/ADT/ilist_node.h" +#include "llvm/IR/GlobalValue.h" +#include "llvm/IR/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? + bool isExternallyInitializedConstant : 1; // Is this a global whose value + // can change from its initial + // value before global + // initializers are run? + +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, + bool isExternallyInitialized = false); + /// 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, + bool isExternallyInitialized = false); + + ~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() && + // The initializer of a global variable with the externally_initialized + // marker may change at runtime before C++ initializers are evaluated. + !isExternallyInitialized(); + } + + /// 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() && + // It is not safe to modify initializers of global variables with the + // external_initializer marker since the value may be changed at runtime + // before C++ initializers are evaluated. + !isExternallyInitialized(); + } + + /// 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); + } + + bool isExternallyInitialized() const { + return isExternallyInitializedConstant; + } + void setExternallyInitialized(bool Val) { + isExternallyInitializedConstant = Val; + } + + /// 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 |
