| //===-- 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, 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/Constant.h" |
| |
| namespace llvm { |
| |
| class PointerType; |
| class Module; |
| |
| 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 = 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. |
| LinkerPrivateWeakLinkage, ///< Like LinkerPrivate, but weak. |
| 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, Use *Ops, unsigned NumOps, |
| LinkageTypes linkage, const Twine &Name) |
| : Constant(ty, vty, Ops, NumOps), Parent(0), |
| Linkage(linkage), Visibility(DefaultVisibility), Alignment(0) { |
| setName(Name); |
| } |
| |
| 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() { |
| 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 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 reinterpret_cast<const PointerType*>(User::getType()); |
| } |
| |
| static LinkageTypes getLinkOnceLinkage(bool ODR) { |
| return ODR ? LinkOnceODRLinkage : LinkOnceAnyLinkage; |
| } |
| static LinkageTypes getWeakLinkage(bool ODR) { |
| return ODR ? WeakODRLinkage : WeakAnyLinkage; |
| } |
| |
| static bool isExternalLinkage(LinkageTypes Linkage) { |
| return Linkage == ExternalLinkage; |
| } |
| static bool isAvailableExternallyLinkage(LinkageTypes Linkage) { |
| return Linkage == AvailableExternallyLinkage; |
| } |
| static bool isLinkOnceLinkage(LinkageTypes Linkage) { |
| return Linkage == LinkOnceAnyLinkage || Linkage == LinkOnceODRLinkage; |
| } |
| static bool isWeakLinkage(LinkageTypes Linkage) { |
| return Linkage == WeakAnyLinkage || Linkage == WeakODRLinkage; |
| } |
| static bool isAppendingLinkage(LinkageTypes Linkage) { |
| return Linkage == AppendingLinkage; |
| } |
| static bool isInternalLinkage(LinkageTypes Linkage) { |
| return Linkage == InternalLinkage; |
| } |
| static bool isPrivateLinkage(LinkageTypes Linkage) { |
| return Linkage == PrivateLinkage; |
| } |
| static bool isLinkerPrivateLinkage(LinkageTypes Linkage) { |
| return Linkage == LinkerPrivateLinkage; |
| } |
| static bool isLinkerPrivateWeakLinkage(LinkageTypes Linkage) { |
| return Linkage == LinkerPrivateWeakLinkage; |
| } |
| static bool isLocalLinkage(LinkageTypes Linkage) { |
| return isInternalLinkage(Linkage) || isPrivateLinkage(Linkage) || |
| isLinkerPrivateLinkage(Linkage) || isLinkerPrivateWeakLinkage(Linkage); |
| } |
| static bool isDLLImportLinkage(LinkageTypes Linkage) { |
| return Linkage == DLLImportLinkage; |
| } |
| static bool isDLLExportLinkage(LinkageTypes Linkage) { |
| return Linkage == DLLExportLinkage; |
| } |
| static bool isExternalWeakLinkage(LinkageTypes Linkage) { |
| return Linkage == ExternalWeakLinkage; |
| } |
| static bool isCommonLinkage(LinkageTypes Linkage) { |
| return Linkage == CommonLinkage; |
| } |
| |
| /// 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. |
| static bool mayBeOverridden(LinkageTypes Linkage) { |
| return (Linkage == WeakAnyLinkage || |
| Linkage == LinkOnceAnyLinkage || |
| Linkage == CommonLinkage || |
| Linkage == ExternalWeakLinkage || |
| Linkage == LinkerPrivateWeakLinkage); |
| } |
| |
| /// isWeakForLinker - Whether the definition of this global may be replaced at |
| /// link time. |
| static bool isWeakForLinker(LinkageTypes Linkage) { |
| return (Linkage == AvailableExternallyLinkage || |
| Linkage == WeakAnyLinkage || |
| Linkage == WeakODRLinkage || |
| Linkage == LinkOnceAnyLinkage || |
| Linkage == LinkOnceODRLinkage || |
| Linkage == CommonLinkage || |
| Linkage == ExternalWeakLinkage || |
| Linkage == LinkerPrivateWeakLinkage); |
| } |
| |
| bool hasExternalLinkage() const { return isExternalLinkage(Linkage); } |
| bool hasAvailableExternallyLinkage() const { |
| return isAvailableExternallyLinkage(Linkage); |
| } |
| bool hasLinkOnceLinkage() const { |
| return isLinkOnceLinkage(Linkage); |
| } |
| bool hasWeakLinkage() const { |
| return isWeakLinkage(Linkage); |
| } |
| bool hasAppendingLinkage() const { return isAppendingLinkage(Linkage); } |
| bool hasInternalLinkage() const { return isInternalLinkage(Linkage); } |
| bool hasPrivateLinkage() const { return isPrivateLinkage(Linkage); } |
| bool hasLinkerPrivateLinkage() const { return isLinkerPrivateLinkage(Linkage); } |
| bool hasLinkerPrivateWeakLinkage() const { |
| return isLinkerPrivateWeakLinkage(Linkage); |
| } |
| bool hasLocalLinkage() const { return isLocalLinkage(Linkage); } |
| bool hasDLLImportLinkage() const { return isDLLImportLinkage(Linkage); } |
| bool hasDLLExportLinkage() const { return isDLLExportLinkage(Linkage); } |
| bool hasExternalWeakLinkage() const { return isExternalWeakLinkage(Linkage); } |
| bool hasCommonLinkage() const { return isCommonLinkage(Linkage); } |
| |
| void setLinkage(LinkageTypes LT) { Linkage = LT; } |
| LinkageTypes getLinkage() const { return Linkage; } |
| |
| bool mayBeOverridden() const { return mayBeOverridden(Linkage); } |
| |
| bool isWeakForLinker() const { return isWeakForLinker(Linkage); } |
| |
| /// 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 *) { return true; } |
| static inline bool classof(const Value *V) { |
| return V->getValueID() == Value::FunctionVal || |
| V->getValueID() == Value::GlobalVariableVal || |
| V->getValueID() == Value::GlobalAliasVal; |
| } |
| }; |
| |
| } // End llvm namespace |
| |
| #endif |