| //===-- 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_IR_GLOBALVALUE_H |
| #define LLVM_IR_GLOBALVALUE_H |
| |
| #include "llvm/IR/Constant.h" |
| #include "llvm/IR/DerivedTypes.h" |
| |
| namespace llvm { |
| |
| class Comdat; |
| 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. |
| 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. |
| 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 |
| }; |
| |
| /// @brief Storage classes of global values for PE targets. |
| enum DLLStorageClassTypes { |
| DefaultStorageClass = 0, |
| DLLImportStorageClass = 1, ///< Function to be imported from DLL |
| DLLExportStorageClass = 2 ///< Function to be accessible from DLL. |
| }; |
| |
| protected: |
| GlobalValue(Type *Ty, ValueTy VTy, Use *Ops, unsigned NumOps, |
| LinkageTypes Linkage, const Twine &Name) |
| : Constant(Ty, VTy, Ops, NumOps), Linkage(Linkage), |
| Visibility(DefaultVisibility), UnnamedAddr(0), |
| DllStorageClass(DefaultStorageClass), |
| ThreadLocal(NotThreadLocal), Parent(nullptr) { |
| 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 UnnamedAddr : 1; // This value's address is not significant |
| unsigned DllStorageClass : 2; // DLL storage class |
| |
| unsigned ThreadLocal : 3; // Is this symbol "Thread Local", if so, what is |
| // the desired model? |
| |
| private: |
| // Give subclasses access to what otherwise would be wasted padding. |
| // (19 + 3 + 2 + 1 + 2 + 5) == 32. |
| unsigned SubClassData : 19; |
| protected: |
| unsigned getGlobalValueSubClassData() const { |
| return SubClassData; |
| } |
| void setGlobalValueSubClassData(unsigned V) { |
| assert(V < (1 << 19) && "It will not fit"); |
| SubClassData = V; |
| } |
| |
| Module *Parent; // The containing module. |
| public: |
| enum ThreadLocalMode { |
| NotThreadLocal = 0, |
| GeneralDynamicTLSModel, |
| LocalDynamicTLSModel, |
| InitialExecTLSModel, |
| LocalExecTLSModel |
| }; |
| |
| ~GlobalValue() { |
| removeDeadConstantUsers(); // remove any dead constants using this. |
| } |
| |
| unsigned getAlignment() const; |
| |
| bool hasUnnamedAddr() const { return UnnamedAddr; } |
| void setUnnamedAddr(bool Val) { UnnamedAddr = Val; } |
| |
| bool hasComdat() const { return getComdat() != nullptr; } |
| Comdat *getComdat(); |
| const Comdat *getComdat() const { |
| return const_cast<GlobalValue *>(this)->getComdat(); |
| } |
| |
| 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) { |
| assert((!hasLocalLinkage() || V == DefaultVisibility) && |
| "local linkage requires default visibility"); |
| Visibility = V; |
| } |
| |
| /// If the value is "Thread Local", its value isn't shared by the threads. |
| bool isThreadLocal() const { return getThreadLocalMode() != NotThreadLocal; } |
| void setThreadLocal(bool Val) { |
| setThreadLocalMode(Val ? GeneralDynamicTLSModel : NotThreadLocal); |
| } |
| void setThreadLocalMode(ThreadLocalMode Val) { |
| assert(Val == NotThreadLocal || getValueID() != Value::FunctionVal); |
| ThreadLocal = Val; |
| } |
| ThreadLocalMode getThreadLocalMode() const { |
| return static_cast<ThreadLocalMode>(ThreadLocal); |
| } |
| |
| DLLStorageClassTypes getDLLStorageClass() const { |
| return DLLStorageClassTypes(DllStorageClass); |
| } |
| bool hasDLLImportStorageClass() const { |
| return DllStorageClass == DLLImportStorageClass; |
| } |
| bool hasDLLExportStorageClass() const { |
| return DllStorageClass == DLLExportStorageClass; |
| } |
| void setDLLStorageClass(DLLStorageClassTypes C) { DllStorageClass = C; } |
| |
| bool hasSection() const { return !StringRef(getSection()).empty(); } |
| // It is unfortunate that we have to use "char *" in here since this is |
| // always non NULL, but: |
| // * The C API expects a null terminated string, so we cannot use StringRef. |
| // * The C API expects us to own it, so we cannot use a std:string. |
| // * For GlobalAliases we can fail to find the section and we have to |
| // return "", so we cannot use a "const std::string &". |
| const char *getSection() const; |
| |
| /// Global values are always pointers. |
| inline PointerType *getType() const { |
| return 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 isLinkOnceODRLinkage(LinkageTypes Linkage) { |
| return Linkage == LinkOnceODRLinkage; |
| } |
| static bool isLinkOnceLinkage(LinkageTypes Linkage) { |
| return Linkage == LinkOnceAnyLinkage || Linkage == LinkOnceODRLinkage; |
| } |
| static bool isWeakAnyLinkage(LinkageTypes Linkage) { |
| return Linkage == WeakAnyLinkage; |
| } |
| static bool isWeakODRLinkage(LinkageTypes Linkage) { |
| return Linkage == WeakODRLinkage; |
| } |
| static bool isWeakLinkage(LinkageTypes Linkage) { |
| return isWeakAnyLinkage(Linkage) || isWeakODRLinkage(Linkage); |
| } |
| 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 isLocalLinkage(LinkageTypes Linkage) { |
| return isInternalLinkage(Linkage) || isPrivateLinkage(Linkage); |
| } |
| static bool isExternalWeakLinkage(LinkageTypes Linkage) { |
| return Linkage == ExternalWeakLinkage; |
| } |
| static bool isCommonLinkage(LinkageTypes Linkage) { |
| return Linkage == CommonLinkage; |
| } |
| |
| /// 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); |
| } |
| |
| /// 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; |
| } |
| |
| /// 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 == CommonLinkage || |
| Linkage == ExternalWeakLinkage; |
| } |
| |
| 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 hasWeakAnyLinkage() const { |
| return isWeakAnyLinkage(Linkage); |
| } |
| bool hasWeakODRLinkage() const { |
| return isWeakODRLinkage(Linkage); |
| } |
| bool hasAppendingLinkage() const { return isAppendingLinkage(Linkage); } |
| bool hasInternalLinkage() const { return isInternalLinkage(Linkage); } |
| bool hasPrivateLinkage() const { return isPrivateLinkage(Linkage); } |
| bool hasLocalLinkage() const { return isLocalLinkage(Linkage); } |
| bool hasExternalWeakLinkage() const { return isExternalWeakLinkage(Linkage); } |
| bool hasCommonLinkage() const { return isCommonLinkage(Linkage); } |
| |
| void setLinkage(LinkageTypes LT) { |
| if (isLocalLinkage(LT)) |
| Visibility = DefaultVisibility; |
| 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); } |
| |
| /// Copy all additional attributes (those not needed to create a GlobalValue) |
| /// from the GlobalValue Src to this one. |
| virtual void copyAttributesFrom(const GlobalValue *Src); |
| |
| /// If special LLVM prefix that is used to inform the asm printer to not emit |
| /// usual symbol prefix before the symbol name is used then return linkage |
| /// name after skipping this special LLVM prefix. |
| static StringRef getRealLinkageName(StringRef Name) { |
| if (!Name.empty() && Name[0] == '\1') |
| return Name.substr(1); |
| return Name; |
| } |
| |
| /// @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. |
| /// @{ |
| |
| /// 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; |
| |
| /// 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; |
| |
| /// 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 = nullptr); |
| |
| /// 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. |
| void destroyConstant() override; |
| |
| /// Return true if the primary definition of this global value is outside of |
| /// the current translation unit. |
| bool isDeclaration() const; |
| |
| /// This method unlinks 'this' from the containing module, but does not delete |
| /// it. |
| virtual void removeFromParent() = 0; |
| |
| /// This method unlinks 'this' from the containing module and deletes it. |
| virtual void eraseFromParent() = 0; |
| |
| /// Get the module that this global value is contained inside of... |
| inline Module *getParent() { return Parent; } |
| inline const Module *getParent() const { return Parent; } |
| |
| const DataLayout *getDataLayout() const; |
| |
| // 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 |