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Diffstat (limited to 'include/llvm/IR/GlobalValue.h')
| -rw-r--r-- | include/llvm/IR/GlobalValue.h | 299 |
1 files changed, 299 insertions, 0 deletions
diff --git a/include/llvm/IR/GlobalValue.h b/include/llvm/IR/GlobalValue.h new file mode 100644 index 0000000000..246e00becf --- /dev/null +++ b/include/llvm/IR/GlobalValue.h @@ -0,0 +1,299 @@ +//===-- 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/IR/Constant.h" + +namespace llvm { + +class PointerType; +class Module; + +class GlobalValue : public Constant { + GlobalValue(const GlobalValue &) LLVM_DELETED_FUNCTION; +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. + LinkOnceODRAutoHideLinkage, ///< Like LinkOnceODRLinkage but addr not taken. + 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(Type *ty, ValueTy vty, Use *Ops, unsigned NumOps, + LinkageTypes linkage, const Twine &Name) + : Constant(ty, vty, Ops, NumOps), Linkage(linkage), + Visibility(DefaultVisibility), Alignment(0), UnnamedAddr(0), Parent(0) { + setName(Name); + } + + // 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 + unsigned UnnamedAddr : 1; // This value's address is not significant + Module *Parent; // The containing module. + std::string Section; // Section to emit this into, empty mean default +public: + ~GlobalValue() { + removeDeadConstantUsers(); // remove any dead constants using this. + } + + unsigned getAlignment() const { + return (1u << Alignment) >> 1; + } + void setAlignment(unsigned Align); + + bool hasUnnamedAddr() const { return UnnamedAddr; } + void setUnnamedAddr(bool Val) { UnnamedAddr = Val; } + + 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 PointerType *getType() const { + return reinterpret_cast<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 || + Linkage == LinkOnceODRAutoHideLinkage; + } + static bool isLinkOnceODRAutoHideLinkage(LinkageTypes Linkage) { + return Linkage == LinkOnceODRAutoHideLinkage; + } + 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; + } + + /// isDiscardableIfUnused - Whether the definition of this global may be + /// discarded if it is not used in its compilation unit. + static bool isDiscardableIfUnused(LinkageTypes Linkage) { + return isLinkOnceLinkage(Linkage) || isLocalLinkage(Linkage); + } + + /// 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. NB: Using this method outside of the code generators is almost + /// always a mistake: when working at the IR level use mayBeOverridden instead + /// as it knows about ODR semantics. + static bool isWeakForLinker(LinkageTypes Linkage) { + return Linkage == AvailableExternallyLinkage || + Linkage == WeakAnyLinkage || + Linkage == WeakODRLinkage || + Linkage == LinkOnceAnyLinkage || + Linkage == LinkOnceODRLinkage || + Linkage == LinkOnceODRAutoHideLinkage || + 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 hasLinkOnceODRAutoHideLinkage() const { + return isLinkOnceODRAutoHideLinkage(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 isDiscardableIfUnused() const { + return isDiscardableIfUnused(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. + virtual void destroyConstant(); + + /// isDeclaration - Return true if the primary definition of this global + /// value is outside of the current translation unit. + bool isDeclaration() const; + + /// 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; } + + // Methods for support type inquiry through isa, cast, and dyn_cast: + static inline bool classof(const Value *V) { + return V->getValueID() == Value::FunctionVal || + V->getValueID() == Value::GlobalVariableVal || + V->getValueID() == Value::GlobalAliasVal; + } +}; + +} // End llvm namespace + +#endif |