1 //===- DeclGroup.h - Classes for representing groups of Decls ---*- 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 defines the DeclGroup, DeclGroupRef, and OwningDeclGroup classes. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_CLANG_AST_DECLGROUP_H 14 #define LLVM_CLANG_AST_DECLGROUP_H 15 16 #include "llvm/Support/TrailingObjects.h" 17 #include <cassert> 18 #include <cstdint> 19 20 namespace clang { 21 22 class ASTContext; 23 class Decl; 24 25 class DeclGroup final : private llvm::TrailingObjects<DeclGroup, Decl *> { 26 // FIXME: Include a TypeSpecifier object. 27 unsigned NumDecls = 0; 28 29 private: 30 DeclGroup() = default; 31 DeclGroup(unsigned numdecls, Decl** decls); 32 33 public: 34 friend TrailingObjects; 35 36 static DeclGroup *Create(ASTContext &C, Decl **Decls, unsigned NumDecls); 37 size()38 unsigned size() const { return NumDecls; } 39 40 Decl *&operator[](unsigned i) { return getTrailingObjects(NumDecls)[i]; } 41 42 Decl* const& operator[](unsigned i) const { 43 return getTrailingObjects(NumDecls)[i]; 44 } 45 }; 46 47 class DeclGroupRef { 48 // Note this is not a PointerIntPair because we need the address of the 49 // non-group case to be valid as a Decl** for iteration. 50 enum Kind { SingleDeclKind=0x0, DeclGroupKind=0x1, Mask=0x1 }; 51 52 Decl* D = nullptr; 53 getKind()54 Kind getKind() const { 55 return (Kind) (reinterpret_cast<uintptr_t>(D) & Mask); 56 } 57 58 public: 59 DeclGroupRef() = default; DeclGroupRef(Decl * d)60 explicit DeclGroupRef(Decl* d) : D(d) {} DeclGroupRef(DeclGroup * dg)61 explicit DeclGroupRef(DeclGroup* dg) 62 : D((Decl*) (reinterpret_cast<uintptr_t>(dg) | DeclGroupKind)) {} 63 Create(ASTContext & C,Decl ** Decls,unsigned NumDecls)64 static DeclGroupRef Create(ASTContext &C, Decl **Decls, unsigned NumDecls) { 65 if (NumDecls == 0) 66 return DeclGroupRef(); 67 if (NumDecls == 1) 68 return DeclGroupRef(Decls[0]); 69 return DeclGroupRef(DeclGroup::Create(C, Decls, NumDecls)); 70 } 71 72 using iterator = Decl **; 73 using const_iterator = Decl * const *; 74 isNull()75 bool isNull() const { return D == nullptr; } isSingleDecl()76 bool isSingleDecl() const { return getKind() == SingleDeclKind; } isDeclGroup()77 bool isDeclGroup() const { return getKind() == DeclGroupKind; } 78 getSingleDecl()79 Decl *getSingleDecl() { 80 assert(isSingleDecl() && "Isn't a single decl"); 81 return D; 82 } getSingleDecl()83 const Decl *getSingleDecl() const { 84 return const_cast<DeclGroupRef*>(this)->getSingleDecl(); 85 } 86 getDeclGroup()87 DeclGroup &getDeclGroup() { 88 assert(isDeclGroup() && "Isn't a declgroup"); 89 return *((DeclGroup*)(reinterpret_cast<uintptr_t>(D) & ~Mask)); 90 } getDeclGroup()91 const DeclGroup &getDeclGroup() const { 92 return const_cast<DeclGroupRef*>(this)->getDeclGroup(); 93 } 94 begin()95 iterator begin() { 96 if (isSingleDecl()) 97 return D ? &D : nullptr; 98 return &getDeclGroup()[0]; 99 } 100 end()101 iterator end() { 102 if (isSingleDecl()) 103 return D ? &D+1 : nullptr; 104 DeclGroup &G = getDeclGroup(); 105 return &G[0] + G.size(); 106 } 107 begin()108 const_iterator begin() const { 109 if (isSingleDecl()) 110 return D ? &D : nullptr; 111 return &getDeclGroup()[0]; 112 } 113 end()114 const_iterator end() const { 115 if (isSingleDecl()) 116 return D ? &D+1 : nullptr; 117 const DeclGroup &G = getDeclGroup(); 118 return &G[0] + G.size(); 119 } 120 getAsOpaquePtr()121 void *getAsOpaquePtr() const { return D; } getFromOpaquePtr(void * Ptr)122 static DeclGroupRef getFromOpaquePtr(void *Ptr) { 123 DeclGroupRef X; 124 X.D = static_cast<Decl*>(Ptr); 125 return X; 126 } 127 }; 128 129 } // namespace clang 130 131 namespace llvm { 132 133 // DeclGroupRef is "like a pointer", implement PointerLikeTypeTraits. 134 template <typename T> 135 struct PointerLikeTypeTraits; 136 template <> 137 struct PointerLikeTypeTraits<clang::DeclGroupRef> { 138 static inline void *getAsVoidPointer(clang::DeclGroupRef P) { 139 return P.getAsOpaquePtr(); 140 } 141 142 static inline clang::DeclGroupRef getFromVoidPointer(void *P) { 143 return clang::DeclGroupRef::getFromOpaquePtr(P); 144 } 145 146 static constexpr int NumLowBitsAvailable = 0; 147 }; 148 149 } // namespace llvm 150 151 #endif // LLVM_CLANG_AST_DECLGROUP_H 152