1 //===-------- llvm/GlobalAlias.h - GlobalAlias class ------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file contains the declaration of the GlobalAlias class, which 10 // represents a single function or variable alias in the IR. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_IR_GLOBALALIAS_H 15 #define LLVM_IR_GLOBALALIAS_H 16 17 #include "llvm/ADT/ilist_node.h" 18 #include "llvm/IR/GlobalValue.h" 19 #include "llvm/IR/OperandTraits.h" 20 #include "llvm/IR/Value.h" 21 22 namespace llvm { 23 24 class Twine; 25 class Module; 26 template <typename ValueSubClass, typename... Args> class SymbolTableListTraits; 27 28 class GlobalAlias : public GlobalValue, public ilist_node<GlobalAlias> { 29 friend class SymbolTableListTraits<GlobalAlias>; 30 31 constexpr static IntrusiveOperandsAllocMarker AllocMarker{1}; 32 33 GlobalAlias(Type *Ty, unsigned AddressSpace, LinkageTypes Linkage, 34 const Twine &Name, Constant *Aliasee, Module *Parent); 35 36 public: 37 GlobalAlias(const GlobalAlias &) = delete; 38 GlobalAlias &operator=(const GlobalAlias &) = delete; 39 40 /// If a parent module is specified, the alias is automatically inserted into 41 /// the end of the specified module's alias list. 42 static GlobalAlias *create(Type *Ty, unsigned AddressSpace, 43 LinkageTypes Linkage, const Twine &Name, 44 Constant *Aliasee, Module *Parent); 45 46 // Without the Aliasee. 47 static GlobalAlias *create(Type *Ty, unsigned AddressSpace, 48 LinkageTypes Linkage, const Twine &Name, 49 Module *Parent); 50 51 // The module is taken from the Aliasee. 52 static GlobalAlias *create(Type *Ty, unsigned AddressSpace, 53 LinkageTypes Linkage, const Twine &Name, 54 GlobalValue *Aliasee); 55 56 // Type, Parent and AddressSpace taken from the Aliasee. 57 static GlobalAlias *create(LinkageTypes Linkage, const Twine &Name, 58 GlobalValue *Aliasee); 59 60 // Linkage, Type, Parent and AddressSpace taken from the Aliasee. 61 static GlobalAlias *create(const Twine &Name, GlobalValue *Aliasee); 62 63 // allocate space for exactly one operand 64 void *operator new(size_t S) { return User::operator new(S, AllocMarker); } 65 void operator delete(void *Ptr) { User::operator delete(Ptr); } 66 67 /// Provide fast operand accessors 68 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant); 69 70 void copyAttributesFrom(const GlobalAlias *Src) { 71 GlobalValue::copyAttributesFrom(Src); 72 } 73 74 /// removeFromParent - This method unlinks 'this' from the containing module, 75 /// but does not delete it. 76 /// 77 void removeFromParent(); 78 79 /// eraseFromParent - This method unlinks 'this' from the containing module 80 /// and deletes it. 81 /// 82 void eraseFromParent(); 83 84 /// These methods retrieve and set alias target. 85 void setAliasee(Constant *Aliasee); 86 const Constant *getAliasee() const { 87 return static_cast<Constant *>(Op<0>().get()); 88 } 89 Constant *getAliasee() { return static_cast<Constant *>(Op<0>().get()); } 90 91 const GlobalObject *getAliaseeObject() const; 92 GlobalObject *getAliaseeObject() { 93 return const_cast<GlobalObject *>( 94 static_cast<const GlobalAlias *>(this)->getAliaseeObject()); 95 } 96 97 static bool isValidLinkage(LinkageTypes L) { 98 return isExternalLinkage(L) || isLocalLinkage(L) || isWeakLinkage(L) || 99 isLinkOnceLinkage(L) || isAvailableExternallyLinkage(L); 100 } 101 102 // Methods for support type inquiry through isa, cast, and dyn_cast: 103 static bool classof(const Value *V) { 104 return V->getValueID() == Value::GlobalAliasVal; 105 } 106 }; 107 108 template <> 109 struct OperandTraits<GlobalAlias> 110 : public FixedNumOperandTraits<GlobalAlias, 1> {}; 111 112 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GlobalAlias, Constant) 113 114 } // end namespace llvm 115 116 #endif // LLVM_IR_GLOBALALIAS_H 117