1//===--- VariantValue.h - Polymorphic value type -*- C++ -*-===/ 2// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 3// See https://llvm.org/LICENSE.txt for license information. 4// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 5// 6//===----------------------------------------------------------------------===// 7/// 8/// \file 9/// Polymorphic value type. 10/// 11/// Supports all the types required for dynamic Matcher construction. 12/// Used by the registry to construct matchers in a generic way. 13/// 14//===----------------------------------------------------------------------===// 15 16#ifndef LLVM_CLANG_ASTMATCHERS_DYNAMIC_VARIANTVALUE_H 17#define LLVM_CLANG_ASTMATCHERS_DYNAMIC_VARIANTVALUE_H 18 19#include "clang/ASTMatchers/ASTMatchers.h" 20#include "clang/ASTMatchers/ASTMatchersInternal.h" 21#include "llvm/ADT/IntrusiveRefCntPtr.h" 22#include "llvm/ADT/Optional.h" 23#include <memory> 24#include <vector> 25 26namespace clang { 27namespace ast_matchers { 28namespace dynamic { 29 30/// Kind identifier. 31/// 32/// It supports all types that VariantValue can contain. 33class ArgKind { 34 public: 35 enum Kind { 36 AK_Matcher, 37 AK_Boolean, 38 AK_Double, 39 AK_Unsigned, 40 AK_String 41 }; 42 /// Constructor for non-matcher types. 43 ArgKind(Kind K) : K(K) { assert(K != AK_Matcher); } 44 45 /// 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 /// 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 /// conversion. 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 /// String representation of the type. 70 std::string asString() const; 71 72private: 73 Kind K; 74 ast_type_traits::ASTNodeKind MatcherKind; 75}; 76 77using ast_matchers::internal::DynTypedMatcher; 78 79/// 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>. 92class VariantMatcher { 93 /// 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 /// 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 /// 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 /// Payload interface to be specialized by each matcher type. 121 /// 122 /// It follows a similar interface as VariantMatcher itself. 123 class Payload { 124 public: 125 virtual ~Payload(); 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 134public: 135 /// A null matcher. 136 VariantMatcher(); 137 138 /// Clones the provided matcher. 139 static VariantMatcher SingleMatcher(const DynTypedMatcher &Matcher); 140 141 /// 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 /// 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 /// Makes the matcher the "null" matcher. 155 void reset(); 156 157 /// Whether the matcher is null. 158 bool isNull() const { return !Value; } 159 160 /// 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 /// 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 /// 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 /// conversion. 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 /// 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 /// 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 211private: 212 explicit VariantMatcher(std::shared_ptr<Payload> Value) 213 : Value(std::move(Value)) {} 214 215 template <typename T> struct TypedMatcherOps; 216 217 class SinglePayload; 218 class PolymorphicPayload; 219 class VariadicOpPayload; 220 221 std::shared_ptr<const Payload> Value; 222}; 223 224template <typename T> 225struct VariantMatcher::TypedMatcherOps final : VariantMatcher::MatcherOps { 226 TypedMatcherOps() 227 : MatcherOps(ast_type_traits::ASTNodeKind::getFromNodeKind<T>()) {} 228 typedef ast_matchers::internal::Matcher<T> MatcherT; 229 230 DynTypedMatcher 231 convertMatcher(const DynTypedMatcher &Matcher) const override { 232 return DynTypedMatcher(Matcher.convertTo<T>()); 233 } 234}; 235 236/// Variant value class. 237/// 238/// Basically, a tagged union with value type semantics. 239/// It is used by the registry as the return value and argument type for the 240/// matcher factory methods. 241/// It can be constructed from any of the supported types. It supports 242/// copy/assignment. 243/// 244/// Supported types: 245/// - \c bool 246// - \c double 247/// - \c unsigned 248/// - \c llvm::StringRef 249/// - \c VariantMatcher (\c DynTypedMatcher / \c Matcher<T>) 250class VariantValue { 251public: 252 VariantValue() : Type(VT_Nothing) {} 253 254 VariantValue(const VariantValue &Other); 255 ~VariantValue(); 256 VariantValue &operator=(const VariantValue &Other); 257 258 /// Specific constructors for each supported type. 259 VariantValue(bool Boolean); 260 VariantValue(double Double); 261 VariantValue(unsigned Unsigned); 262 VariantValue(StringRef String); 263 VariantValue(const VariantMatcher &Matchers); 264 265 /// Constructs an \c unsigned value (disambiguation from bool). 266 VariantValue(int Signed) : VariantValue(static_cast<unsigned>(Signed)) {} 267 268 /// Returns true iff this is not an empty value. 269 explicit operator bool() const { return hasValue(); } 270 bool hasValue() const { return Type != VT_Nothing; } 271 272 /// Boolean value functions. 273 bool isBoolean() const; 274 bool getBoolean() const; 275 void setBoolean(bool Boolean); 276 277 /// Double value functions. 278 bool isDouble() const; 279 double getDouble() const; 280 void setDouble(double Double); 281 282 /// Unsigned value functions. 283 bool isUnsigned() const; 284 unsigned getUnsigned() const; 285 void setUnsigned(unsigned Unsigned); 286 287 /// String value functions. 288 bool isString() const; 289 const std::string &getString() const; 290 void setString(StringRef String); 291 292 /// Matcher value functions. 293 bool isMatcher() const; 294 const VariantMatcher &getMatcher() const; 295 void setMatcher(const VariantMatcher &Matcher); 296 297 /// Determines if the contained value can be converted to \p Kind. 298 /// 299 /// \param Kind the requested destination type. 300 /// 301 /// \param Specificity value corresponding to the "specificity" of the 302 /// conversion. 303 bool isConvertibleTo(ArgKind Kind, unsigned* Specificity) const; 304 305 /// Determines if the contained value can be converted to any kind 306 /// in \p Kinds. 307 /// 308 /// \param Kinds the requested destination types. 309 /// 310 /// \param Specificity value corresponding to the "specificity" of the 311 /// conversion. It is the maximum specificity of all the possible 312 /// conversions. 313 bool isConvertibleTo(ArrayRef<ArgKind> Kinds, unsigned *Specificity) const; 314 315 /// String representation of the type of the value. 316 std::string getTypeAsString() const; 317 318private: 319 void reset(); 320 321 /// All supported value types. 322 enum ValueType { 323 VT_Nothing, 324 VT_Boolean, 325 VT_Double, 326 VT_Unsigned, 327 VT_String, 328 VT_Matcher 329 }; 330 331 /// All supported value types. 332 union AllValues { 333 unsigned Unsigned; 334 double Double; 335 bool Boolean; 336 std::string *String; 337 VariantMatcher *Matcher; 338 }; 339 340 ValueType Type; 341 AllValues Value; 342}; 343 344} // end namespace dynamic 345} // end namespace ast_matchers 346} // end namespace clang 347 348#endif // LLVM_CLANG_AST_MATCHERS_DYNAMIC_VARIANT_VALUE_H 349