1 //===--- VariantValue.h - Polymorphic value type -*- C++ -*-===/ 2 // The LLVM Compiler Infrastructure 3 // 4 // This file is distributed under the University of Illinois Open Source 5 // License. See LICENSE.TXT for details. 6 // 7 //===----------------------------------------------------------------------===// 8 /// 9 /// \file 10 /// \brief Polymorphic value type. 11 /// 12 /// Supports all the types required for dynamic Matcher construction. 13 /// Used by the registry to construct matchers in a generic way. 14 /// 15 //===----------------------------------------------------------------------===// 16 17 #ifndef LLVM_CLANG_ASTMATCHERS_DYNAMIC_VARIANTVALUE_H 18 #define LLVM_CLANG_ASTMATCHERS_DYNAMIC_VARIANTVALUE_H 19 20 #include "clang/ASTMatchers/ASTMatchers.h" 21 #include "clang/ASTMatchers/ASTMatchersInternal.h" 22 #include "llvm/ADT/IntrusiveRefCntPtr.h" 23 #include "llvm/ADT/Optional.h" 24 #include "llvm/ADT/Twine.h" 25 #include <memory> 26 #include <vector> 27 28 namespace clang { 29 namespace ast_matchers { 30 namespace dynamic { 31 32 /// \brief Kind identifier. 33 /// 34 /// It supports all types that VariantValue can contain. 35 class ArgKind { 36 public: 37 enum Kind { 38 AK_Matcher, 39 AK_Unsigned, 40 AK_String 41 }; 42 /// \brief Constructor for non-matcher types. 43 ArgKind(Kind K) : K(K) { assert(K != AK_Matcher); } 44 45 /// \brief Constructor for matcher types. 46 ArgKind(ast_type_traits::ASTNodeKind MatcherKind) 47 : K(AK_Matcher), MatcherKind(MatcherKind) {} 48 49 Kind getArgKind() const { return K; } 50 ast_type_traits::ASTNodeKind getMatcherKind() const { 51 assert(K == AK_Matcher); 52 return MatcherKind; 53 } 54 55 /// \brief Determines if this type can be converted to \p To. 56 /// 57 /// \param To the requested destination type. 58 /// 59 /// \param Specificity value corresponding to the "specificity" of the 60 /// convertion. 61 bool isConvertibleTo(ArgKind To, unsigned *Specificity) const; 62 63 bool operator<(const ArgKind &Other) const { 64 if (K == AK_Matcher && Other.K == AK_Matcher) 65 return MatcherKind < Other.MatcherKind; 66 return K < Other.K; 67 } 68 69 /// \brief String representation of the type. 70 std::string asString() const; 71 72 private: 73 Kind K; 74 ast_type_traits::ASTNodeKind MatcherKind; 75 }; 76 77 using ast_matchers::internal::DynTypedMatcher; 78 79 /// \brief A variant matcher object. 80 /// 81 /// The purpose of this object is to abstract simple and polymorphic matchers 82 /// into a single object type. 83 /// Polymorphic matchers might be implemented as a list of all the possible 84 /// overloads of the matcher. \c VariantMatcher knows how to select the 85 /// appropriate overload when needed. 86 /// To get a real matcher object out of a \c VariantMatcher you can do: 87 /// - getSingleMatcher() which returns a matcher, only if it is not ambiguous 88 /// to decide which matcher to return. Eg. it contains only a single 89 /// matcher, or a polymorphic one with only one overload. 90 /// - hasTypedMatcher<T>()/getTypedMatcher<T>(): These calls will determine if 91 /// the underlying matcher(s) can unambiguously return a Matcher<T>. 92 class VariantMatcher { 93 /// \brief Methods that depend on T from hasTypedMatcher/getTypedMatcher. 94 class MatcherOps { 95 public: 96 MatcherOps(ast_type_traits::ASTNodeKind NodeKind) : NodeKind(NodeKind) {} 97 98 bool canConstructFrom(const DynTypedMatcher &Matcher, 99 bool &IsExactMatch) const; 100 101 /// \brief Convert \p Matcher the destination type and return it as a new 102 /// DynTypedMatcher. 103 virtual DynTypedMatcher 104 convertMatcher(const DynTypedMatcher &Matcher) const = 0; 105 106 /// \brief Constructs a variadic typed matcher from \p InnerMatchers. 107 /// Will try to convert each inner matcher to the destination type and 108 /// return llvm::None if it fails to do so. 109 llvm::Optional<DynTypedMatcher> 110 constructVariadicOperator(DynTypedMatcher::VariadicOperator Op, 111 ArrayRef<VariantMatcher> InnerMatchers) const; 112 113 protected: 114 ~MatcherOps() = default; 115 116 private: 117 ast_type_traits::ASTNodeKind NodeKind; 118 }; 119 120 /// \brief Payload interface to be specialized by each matcher type. 121 /// 122 /// It follows a similar interface as VariantMatcher itself. 123 class Payload : public RefCountedBaseVPTR { 124 public: 125 ~Payload() override; 126 virtual llvm::Optional<DynTypedMatcher> getSingleMatcher() const = 0; 127 virtual std::string getTypeAsString() const = 0; 128 virtual llvm::Optional<DynTypedMatcher> 129 getTypedMatcher(const MatcherOps &Ops) const = 0; 130 virtual bool isConvertibleTo(ast_type_traits::ASTNodeKind Kind, 131 unsigned *Specificity) const = 0; 132 }; 133 134 public: 135 /// \brief A null matcher. 136 VariantMatcher(); 137 138 /// \brief Clones the provided matcher. 139 static VariantMatcher SingleMatcher(const DynTypedMatcher &Matcher); 140 141 /// \brief Clones the provided matchers. 142 /// 143 /// They should be the result of a polymorphic matcher. 144 static VariantMatcher 145 PolymorphicMatcher(std::vector<DynTypedMatcher> Matchers); 146 147 /// \brief Creates a 'variadic' operator matcher. 148 /// 149 /// It will bind to the appropriate type on getTypedMatcher<T>(). 150 static VariantMatcher 151 VariadicOperatorMatcher(DynTypedMatcher::VariadicOperator Op, 152 std::vector<VariantMatcher> Args); 153 154 /// \brief Makes the matcher the "null" matcher. 155 void reset(); 156 157 /// \brief Whether the matcher is null. 158 bool isNull() const { return !Value; } 159 160 /// \brief Return a single matcher, if there is no ambiguity. 161 /// 162 /// \returns the matcher, if there is only one matcher. An empty Optional, if 163 /// the underlying matcher is a polymorphic matcher with more than one 164 /// representation. 165 llvm::Optional<DynTypedMatcher> getSingleMatcher() const; 166 167 /// \brief Determines if the contained matcher can be converted to 168 /// \c Matcher<T>. 169 /// 170 /// For the Single case, it returns true if it can be converted to 171 /// \c Matcher<T>. 172 /// For the Polymorphic case, it returns true if one, and only one, of the 173 /// overloads can be converted to \c Matcher<T>. If there are more than one 174 /// that can, the result would be ambiguous and false is returned. 175 template <class T> 176 bool hasTypedMatcher() const { 177 if (!Value) return false; 178 return Value->getTypedMatcher(TypedMatcherOps<T>()).hasValue(); 179 } 180 181 /// \brief Determines if the contained matcher can be converted to \p Kind. 182 /// 183 /// \param Kind the requested destination type. 184 /// 185 /// \param Specificity value corresponding to the "specificity" of the 186 /// convertion. 187 bool isConvertibleTo(ast_type_traits::ASTNodeKind Kind, 188 unsigned *Specificity) const { 189 if (Value) 190 return Value->isConvertibleTo(Kind, Specificity); 191 return false; 192 } 193 194 /// \brief Return this matcher as a \c Matcher<T>. 195 /// 196 /// Handles the different types (Single, Polymorphic) accordingly. 197 /// Asserts that \c hasTypedMatcher<T>() is true. 198 template <class T> 199 ast_matchers::internal::Matcher<T> getTypedMatcher() const { 200 assert(hasTypedMatcher<T>() && "hasTypedMatcher<T>() == false"); 201 return Value->getTypedMatcher(TypedMatcherOps<T>()) 202 ->template convertTo<T>(); 203 } 204 205 /// \brief String representation of the type of the value. 206 /// 207 /// If the underlying matcher is a polymorphic one, the string will show all 208 /// the types. 209 std::string getTypeAsString() const; 210 211 private: 212 explicit VariantMatcher(Payload *Value) : Value(Value) {} 213 214 template <typename T> struct TypedMatcherOps; 215 216 class SinglePayload; 217 class PolymorphicPayload; 218 class VariadicOpPayload; 219 220 IntrusiveRefCntPtr<const Payload> Value; 221 }; 222 223 template <typename T> 224 struct VariantMatcher::TypedMatcherOps final : VariantMatcher::MatcherOps { 225 TypedMatcherOps() 226 : MatcherOps(ast_type_traits::ASTNodeKind::getFromNodeKind<T>()) {} 227 typedef ast_matchers::internal::Matcher<T> MatcherT; 228 229 DynTypedMatcher 230 convertMatcher(const DynTypedMatcher &Matcher) const override { 231 return DynTypedMatcher(Matcher.convertTo<T>()); 232 } 233 }; 234 235 /// \brief Variant value class. 236 /// 237 /// Basically, a tagged union with value type semantics. 238 /// It is used by the registry as the return value and argument type for the 239 /// matcher factory methods. 240 /// It can be constructed from any of the supported types. It supports 241 /// copy/assignment. 242 /// 243 /// Supported types: 244 /// - \c unsigned 245 /// - \c llvm::StringRef 246 /// - \c VariantMatcher (\c DynTypedMatcher / \c Matcher<T>) 247 class VariantValue { 248 public: 249 VariantValue() : Type(VT_Nothing) {} 250 251 VariantValue(const VariantValue &Other); 252 ~VariantValue(); 253 VariantValue &operator=(const VariantValue &Other); 254 255 /// \brief Specific constructors for each supported type. 256 VariantValue(unsigned Unsigned); 257 VariantValue(StringRef String); 258 VariantValue(const VariantMatcher &Matchers); 259 260 /// \brief Returns true iff this is not an empty value. 261 explicit operator bool() const { return hasValue(); } 262 bool hasValue() const { return Type != VT_Nothing; } 263 264 /// \brief Unsigned value functions. 265 bool isUnsigned() const; 266 unsigned getUnsigned() const; 267 void setUnsigned(unsigned Unsigned); 268 269 /// \brief String value functions. 270 bool isString() const; 271 const std::string &getString() const; 272 void setString(StringRef String); 273 274 /// \brief Matcher value functions. 275 bool isMatcher() const; 276 const VariantMatcher &getMatcher() const; 277 void setMatcher(const VariantMatcher &Matcher); 278 279 /// \brief Determines if the contained value can be converted to \p Kind. 280 /// 281 /// \param Kind the requested destination type. 282 /// 283 /// \param Specificity value corresponding to the "specificity" of the 284 /// convertion. 285 bool isConvertibleTo(ArgKind Kind, unsigned* Specificity) const; 286 287 /// \brief Determines if the contained value can be converted to any kind 288 /// in \p Kinds. 289 /// 290 /// \param Kinds the requested destination types. 291 /// 292 /// \param Specificity value corresponding to the "specificity" of the 293 /// convertion. It is the maximum specificity of all the possible 294 /// conversions. 295 bool isConvertibleTo(ArrayRef<ArgKind> Kinds, unsigned *Specificity) const; 296 297 /// \brief String representation of the type of the value. 298 std::string getTypeAsString() const; 299 300 private: 301 void reset(); 302 303 /// \brief All supported value types. 304 enum ValueType { 305 VT_Nothing, 306 VT_Unsigned, 307 VT_String, 308 VT_Matcher 309 }; 310 311 /// \brief All supported value types. 312 union AllValues { 313 unsigned Unsigned; 314 std::string *String; 315 VariantMatcher *Matcher; 316 }; 317 318 ValueType Type; 319 AllValues Value; 320 }; 321 322 } // end namespace dynamic 323 } // end namespace ast_matchers 324 } // end namespace clang 325 326 #endif // LLVM_CLANG_AST_MATCHERS_DYNAMIC_VARIANT_VALUE_H 327
