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VariantValue.h
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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 
21 #include "llvm/ADT/IntrusiveRefCntPtr.h"
22 #include "llvm/ADT/Optional.h"
23 #include <memory>
24 #include <vector>
25 
26 namespace clang {
27 namespace ast_matchers {
28 namespace dynamic {
29 
30 /// Kind identifier.
31 ///
32 /// It supports all types that VariantValue can contain.
33 class ArgKind {
34  public:
35  enum Kind {
41  };
42  /// Constructor for non-matcher types.
43  ArgKind(Kind K) : K(K) { assert(K != AK_Matcher); }
44 
45  /// Constructor for matcher types.
47  : K(AK_Matcher), MatcherKind(MatcherKind) {}
48 
49  Kind getArgKind() const { return K; }
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 
72 private:
73  Kind K;
74  ast_type_traits::ASTNodeKind MatcherKind;
75 };
76 
77 using 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>.
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.
110  constructVariadicOperator(DynTypedMatcher::VariadicOperator Op,
111  ArrayRef<VariantMatcher> InnerMatchers) const;
112 
113  protected:
114  ~MatcherOps() = default;
115 
116  private:
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;
129  getTypedMatcher(const MatcherOps &Ops) const = 0;
131  unsigned *Specificity) const = 0;
132  };
133 
134 public:
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.
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 
211 private:
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 
224 template <typename T>
225 struct 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>)
251 public:
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 
318 private:
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
bool hasTypedMatcher() const
Determines if the contained matcher can be converted to Matcher<T>.
Definition: VariantValue.h:176
std::string asString() const
String representation of the type.
The base class of the type hierarchy.
Definition: Type.h:1414
bool operator<(const ArgKind &Other) const
Definition: VariantValue.h:63
ast_matchers::internal::Matcher< T > getTypedMatcher() const
Return this matcher as a Matcher<T>.
Definition: VariantValue.h:199
bool isConvertibleTo(ArgKind To, unsigned *Specificity) const
Determines if this type can be converted to To.
VariantValue(int Signed)
Constructs an unsigned value (disambiguation from bool).
Definition: VariantValue.h:266
ArgKind(Kind K)
Constructor for non-matcher types.
Definition: VariantValue.h:43
#define bool
Definition: stdbool.h:15
Kind
Dataflow Directional Tag Classes.
ArgKind(ast_type_traits::ASTNodeKind MatcherKind)
Constructor for matcher types.
Definition: VariantValue.h:46
bool isNull() const
Whether the matcher is null.
Definition: VariantValue.h:158
bool isConvertibleTo(ast_type_traits::ASTNodeKind Kind, unsigned *Specificity) const
Determines if the contained matcher can be converted to Kind.
Definition: VariantValue.h:187
ast_type_traits::ASTNodeKind getMatcherKind() const
Definition: VariantValue.h:50