//===-- llvm/GlobalValue.h - Class to represent a global value --*- C++ -*-===//
//
+// The LLVM Compiler Infrastructure
+//
+// This file 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
-// can do certain things with these global objects that you can't do to anything
-// else. For example, use the address of one as a constant.
+// it is subclassed by GlobalVariable, GlobalAlias and by Function. This is
+// used because you can do certain things with these global objects that you
+// can't do to anything else. For example, use the address of one as a
+// constant.
//
//===----------------------------------------------------------------------===//
#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:
+ /// @brief An enumeration for the kinds of linkage for global values.
enum LinkageTypes {
- ExternalLinkage, // Externally visible function
- LinkOnceLinkage, // Keep one copy of named function when linking (inline)
- AppendingLinkage, // Special purpose, only applies to global arrays
- InternalLinkage // Rename collisions when linking (static functions)
+ ExternalLinkage = 0,///< Externally visible function
+ AvailableExternallyLinkage, ///< Available for inspection, not emission.
+ LinkOnceAnyLinkage, ///< Keep one copy of function when linking (inline)
+ LinkOnceODRLinkage, ///< Same, but only replaced by something equivalent.
+ WeakAnyLinkage, ///< Keep one copy of named function when linking (weak)
+ WeakODRLinkage, ///< Same, but only replaced by something equivalent.
+ AppendingLinkage, ///< Special purpose, only applies to global arrays
+ InternalLinkage, ///< Rename collisions when linking (static functions).
+ PrivateLinkage, ///< Like Internal, but omit from symbol table.
+ LinkerPrivateLinkage, ///< Like Private, but linker removes.
+ DLLImportLinkage, ///< Function to be imported from DLL
+ DLLExportLinkage, ///< Function to be accessible from DLL.
+ ExternalWeakLinkage,///< ExternalWeak linkage description.
+ CommonLinkage ///< Tentative definitions.
+ };
+
+ /// @brief An enumeration for the kinds of visibility of global values.
+ enum VisibilityTypes {
+ DefaultVisibility = 0, ///< The GV is visible
+ HiddenVisibility, ///< The GV is hidden
+ ProtectedVisibility ///< The GV is protected
};
+
protected:
- GlobalValue(const Type *Ty, ValueTy vty, LinkageTypes linkage,
- const std::string &name = "")
- : User(Ty, vty, name), Linkage(linkage), Parent(0) {}
+ GlobalValue(const Type *ty, ValueTy vty, Use *Ops, unsigned NumOps,
+ LinkageTypes linkage, const Twine &Name)
+ : Constant(ty, vty, Ops, NumOps), Parent(0),
+ Linkage(linkage), Visibility(DefaultVisibility), Alignment(0) {
+ setName(Name);
+ }
- LinkageTypes Linkage; // The linkage of this global
Module *Parent;
+ // Note: VC++ treats enums as signed, so an extra bit is required to prevent
+ // Linkage and Visibility from turning into negative values.
+ LinkageTypes Linkage : 5; // The linkage of this global
+ unsigned Visibility : 2; // The visibility style of this global
+ unsigned Alignment : 16; // Alignment of this symbol, must be power of two
+ std::string Section; // Section to emit this into, empty mean default
public:
- ~GlobalValue() {}
+ ~GlobalValue() {
+ removeDeadConstantUsers(); // remove any dead constants using this.
+ }
+
+ unsigned getAlignment() const { return Alignment; }
+ void setAlignment(unsigned Align) {
+ assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
+ Alignment = Align;
+ }
+
+ VisibilityTypes getVisibility() const { return VisibilityTypes(Visibility); }
+ bool hasDefaultVisibility() const { return Visibility == DefaultVisibility; }
+ bool hasHiddenVisibility() const { return Visibility == HiddenVisibility; }
+ bool hasProtectedVisibility() const {
+ return Visibility == ProtectedVisibility;
+ }
+ void setVisibility(VisibilityTypes V) { Visibility = V; }
+
+ bool hasSection() const { return !Section.empty(); }
+ const std::string &getSection() const { return Section; }
+ void setSection(StringRef S) { Section = S; }
+
+ /// 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());
}
- bool hasExternalLinkage() const { return Linkage == ExternalLinkage; }
- bool hasLinkOnceLinkage() const { return Linkage == LinkOnceLinkage; }
+ static LinkageTypes getLinkOnceLinkage(bool ODR) {
+ return ODR ? LinkOnceODRLinkage : LinkOnceAnyLinkage;
+ }
+ static LinkageTypes getWeakLinkage(bool ODR) {
+ return ODR ? WeakODRLinkage : WeakAnyLinkage;
+ }
+
+ bool hasExternalLinkage() const { return Linkage == ExternalLinkage; }
+ bool hasAvailableExternallyLinkage() const {
+ return Linkage == AvailableExternallyLinkage;
+ }
+ bool hasLinkOnceLinkage() const {
+ return Linkage == LinkOnceAnyLinkage || Linkage == LinkOnceODRLinkage;
+ }
+ bool hasWeakLinkage() const {
+ return Linkage == WeakAnyLinkage || Linkage == WeakODRLinkage;
+ }
bool hasAppendingLinkage() const { return Linkage == AppendingLinkage; }
- bool hasInternalLinkage() const { return Linkage == InternalLinkage; }
+ bool hasInternalLinkage() const { return Linkage == InternalLinkage; }
+ bool hasPrivateLinkage() const { return Linkage == PrivateLinkage; }
+ bool hasLinkerPrivateLinkage() const { return Linkage==LinkerPrivateLinkage; }
+ bool hasLocalLinkage() const {
+ return hasInternalLinkage() || hasPrivateLinkage() ||
+ hasLinkerPrivateLinkage();
+ }
+ bool hasDLLImportLinkage() const { return Linkage == DLLImportLinkage; }
+ bool hasDLLExportLinkage() const { return Linkage == DLLExportLinkage; }
+ bool hasExternalWeakLinkage() const { return Linkage == ExternalWeakLinkage; }
+ bool hasCommonLinkage() const { return Linkage == CommonLinkage; }
+
void setLinkage(LinkageTypes LT) { Linkage = LT; }
LinkageTypes getLinkage() const { return Linkage; }
- /// isExternal - Return true if the primary definition of this global value is
- /// outside of the current translation unit...
- virtual bool isExternal() const = 0;
+ /// mayBeOverridden - Whether the definition of this global may be replaced
+ /// by something non-equivalent at link time. For example, if a function has
+ /// weak linkage then the code defining it may be replaced by different code.
+ bool mayBeOverridden() const {
+ return (Linkage == WeakAnyLinkage ||
+ Linkage == LinkOnceAnyLinkage ||
+ Linkage == CommonLinkage ||
+ Linkage == ExternalWeakLinkage);
+ }
+
+ /// isWeakForLinker - Whether the definition of this global may be replaced at
+ /// link time.
+ bool isWeakForLinker() const {
+ return (Linkage == AvailableExternallyLinkage ||
+ Linkage == WeakAnyLinkage ||
+ Linkage == WeakODRLinkage ||
+ Linkage == LinkOnceAnyLinkage ||
+ Linkage == LinkOnceODRLinkage ||
+ Linkage == CommonLinkage ||
+ Linkage == ExternalWeakLinkage);
+ }
+
+ /// copyAttributesFrom - copy all additional attributes (those not needed to
+ /// create a GlobalValue) from the GlobalValue Src to this one.
+ virtual void copyAttributesFrom(const GlobalValue *Src);
+
+/// @name Materialization
+/// Materialization is used to construct functions only as they're needed. This
+/// is useful to reduce memory usage in LLVM or parsing work done by the
+/// BitcodeReader to load the Module.
+/// @{
+
+ /// isMaterializable - If this function's Module is being lazily streamed in
+ /// functions from disk or some other source, this method can be used to check
+ /// to see if the function has been read in yet or not.
+ bool isMaterializable() const;
+
+ /// isDematerializable - Returns true if this function was loaded from a
+ /// GVMaterializer that's still attached to its Module and that knows how to
+ /// dematerialize the function.
+ bool isDematerializable() const;
+
+ /// Materialize - make sure this GlobalValue is fully read. If the module is
+ /// corrupt, this returns true and fills in the optional string with
+ /// information about the problem. If successful, this returns false.
+ bool Materialize(std::string *ErrInfo = 0);
+
+ /// Dematerialize - If this GlobalValue is read in, and if the GVMaterializer
+ /// supports it, release the memory for the function, and set it up to be
+ /// materialized lazily. If !isDematerializable(), this method is a noop.
+ void Dematerialize();
+
+/// @}
+
+ /// 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();
+
+ /// isDeclaration - Return true if the primary definition of this global
+ /// value is outside of the current translation unit...
+ virtual bool isDeclaration() const = 0;
+
+ /// removeFromParent - This method unlinks 'this' from the containing module,
+ /// but does not delete it.
+ virtual void removeFromParent() = 0;
+
+ /// eraseFromParent - This method unlinks 'this' from the containing module
+ /// and deletes it.
+ virtual void eraseFromParent() = 0;
/// getParent - Get the module that this global value is contained inside
/// of...
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.
+ void removeDeadConstantUsers() const;
+
// 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 GlobalValue *) { return true; }
static inline bool classof(const Value *V) {
- return V->getValueType() == Value::FunctionVal ||
- V->getValueType() == Value::GlobalVariableVal;
+ return V->getValueID() == Value::FunctionVal ||
+ V->getValueID() == Value::GlobalVariableVal ||
+ V->getValueID() == Value::GlobalAliasVal;
}
};
+} // End llvm namespace
+
#endif
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