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NestedNameSpecifier.h
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1 //===- NestedNameSpecifier.h - C++ nested name specifiers -------*- 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 NestedNameSpecifier class, which represents
10 // a C++ nested-name-specifier.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_AST_NESTEDNAMESPECIFIER_H
15 #define LLVM_CLANG_AST_NESTEDNAMESPECIFIER_H
16 
17 #include "clang/Basic/Diagnostic.h"
19 #include "llvm/ADT/FoldingSet.h"
20 #include "llvm/ADT/PointerIntPair.h"
21 #include "llvm/Support/Compiler.h"
22 #include <cstdint>
23 #include <cstdlib>
24 #include <utility>
25 
26 namespace clang {
27 
28 class ASTContext;
29 class CXXRecordDecl;
30 class IdentifierInfo;
31 class LangOptions;
32 class NamespaceAliasDecl;
33 class NamespaceDecl;
34 struct PrintingPolicy;
35 class Type;
36 class TypeLoc;
37 
38 /// Represents a C++ nested name specifier, such as
39 /// "\::std::vector<int>::".
40 ///
41 /// C++ nested name specifiers are the prefixes to qualified
42 /// names. For example, "foo::" in "foo::x" is a nested name
43 /// specifier. Nested name specifiers are made up of a sequence of
44 /// specifiers, each of which can be a namespace, type, identifier
45 /// (for dependent names), decltype specifier, or the global specifier ('::').
46 /// The last two specifiers can only appear at the start of a
47 /// nested-namespace-specifier.
48 class NestedNameSpecifier : public llvm::FoldingSetNode {
49  /// Enumeration describing
50  enum StoredSpecifierKind {
51  StoredIdentifier = 0,
52  StoredDecl = 1,
53  StoredTypeSpec = 2,
54  StoredTypeSpecWithTemplate = 3
55  };
56 
57  /// The nested name specifier that precedes this nested name
58  /// specifier.
59  ///
60  /// The pointer is the nested-name-specifier that precedes this
61  /// one. The integer stores one of the first four values of type
62  /// SpecifierKind.
63  llvm::PointerIntPair<NestedNameSpecifier *, 2, StoredSpecifierKind> Prefix;
64 
65  /// The last component in the nested name specifier, which
66  /// can be an identifier, a declaration, or a type.
67  ///
68  /// When the pointer is NULL, this specifier represents the global
69  /// specifier '::'. Otherwise, the pointer is one of
70  /// IdentifierInfo*, Namespace*, or Type*, depending on the kind of
71  /// specifier as encoded within the prefix.
72  void* Specifier = nullptr;
73 
74 public:
75  /// The kind of specifier that completes this nested name
76  /// specifier.
78  /// An identifier, stored as an IdentifierInfo*.
80 
81  /// A namespace, stored as a NamespaceDecl*.
83 
84  /// A namespace alias, stored as a NamespaceAliasDecl*.
86 
87  /// A type, stored as a Type*.
89 
90  /// A type that was preceded by the 'template' keyword,
91  /// stored as a Type*.
93 
94  /// The global specifier '::'. There is no stored value.
96 
97  /// Microsoft's '__super' specifier, stored as a CXXRecordDecl* of
98  /// the class it appeared in.
100  };
101 
102 private:
103  /// Builds the global specifier.
104  NestedNameSpecifier() : Prefix(nullptr, StoredIdentifier) {}
105 
106  /// Copy constructor used internally to clone nested name
107  /// specifiers.
108  NestedNameSpecifier(const NestedNameSpecifier &Other) = default;
109 
110  /// Either find or insert the given nested name specifier
111  /// mockup in the given context.
112  static NestedNameSpecifier *FindOrInsert(const ASTContext &Context,
113  const NestedNameSpecifier &Mockup);
114 
115 public:
117 
118  /// Builds a specifier combining a prefix and an identifier.
119  ///
120  /// The prefix must be dependent, since nested name specifiers
121  /// referencing an identifier are only permitted when the identifier
122  /// cannot be resolved.
123  static NestedNameSpecifier *Create(const ASTContext &Context,
124  NestedNameSpecifier *Prefix,
125  IdentifierInfo *II);
126 
127  /// Builds a nested name specifier that names a namespace.
128  static NestedNameSpecifier *Create(const ASTContext &Context,
129  NestedNameSpecifier *Prefix,
130  const NamespaceDecl *NS);
131 
132  /// Builds a nested name specifier that names a namespace alias.
133  static NestedNameSpecifier *Create(const ASTContext &Context,
134  NestedNameSpecifier *Prefix,
135  NamespaceAliasDecl *Alias);
136 
137  /// Builds a nested name specifier that names a type.
138  static NestedNameSpecifier *Create(const ASTContext &Context,
139  NestedNameSpecifier *Prefix,
140  bool Template, const Type *T);
141 
142  /// Builds a specifier that consists of just an identifier.
143  ///
144  /// The nested-name-specifier is assumed to be dependent, but has no
145  /// prefix because the prefix is implied by something outside of the
146  /// nested name specifier, e.g., in "x->Base::f", the "x" has a dependent
147  /// type.
148  static NestedNameSpecifier *Create(const ASTContext &Context,
149  IdentifierInfo *II);
150 
151  /// Returns the nested name specifier representing the global
152  /// scope.
153  static NestedNameSpecifier *GlobalSpecifier(const ASTContext &Context);
154 
155  /// Returns the nested name specifier representing the __super scope
156  /// for the given CXXRecordDecl.
157  static NestedNameSpecifier *SuperSpecifier(const ASTContext &Context,
158  CXXRecordDecl *RD);
159 
160  /// Return the prefix of this nested name specifier.
161  ///
162  /// The prefix contains all of the parts of the nested name
163  /// specifier that preced this current specifier. For example, for a
164  /// nested name specifier that represents "foo::bar::", the current
165  /// specifier will contain "bar::" and the prefix will contain
166  /// "foo::".
167  NestedNameSpecifier *getPrefix() const { return Prefix.getPointer(); }
168 
169  /// Determine what kind of nested name specifier is stored.
170  SpecifierKind getKind() const;
171 
172  /// Retrieve the identifier stored in this nested name
173  /// specifier.
175  if (Prefix.getInt() == StoredIdentifier)
176  return (IdentifierInfo *)Specifier;
177 
178  return nullptr;
179  }
180 
181  /// Retrieve the namespace stored in this nested name
182  /// specifier.
183  NamespaceDecl *getAsNamespace() const;
184 
185  /// Retrieve the namespace alias stored in this nested name
186  /// specifier.
188 
189  /// Retrieve the record declaration stored in this nested name
190  /// specifier.
192 
193  /// Retrieve the type stored in this nested name specifier.
194  const Type *getAsType() const {
195  if (Prefix.getInt() == StoredTypeSpec ||
196  Prefix.getInt() == StoredTypeSpecWithTemplate)
197  return (const Type *)Specifier;
198 
199  return nullptr;
200  }
201 
202  /// Whether this nested name specifier refers to a dependent
203  /// type or not.
204  bool isDependent() const;
205 
206  /// Whether this nested name specifier involves a template
207  /// parameter.
208  bool isInstantiationDependent() const;
209 
210  /// Whether this nested-name-specifier contains an unexpanded
211  /// parameter pack (for C++11 variadic templates).
212  bool containsUnexpandedParameterPack() const;
213 
214  /// Print this nested name specifier to the given output stream. If
215  /// `ResolveTemplateArguments` is true, we'll print actual types, e.g.
216  /// `ns::SomeTemplate<int, MyClass>` instead of
217  /// `ns::SomeTemplate<Container::value_type, T>`.
218  void print(raw_ostream &OS, const PrintingPolicy &Policy,
219  bool ResolveTemplateArguments = false) const;
220 
221  void Profile(llvm::FoldingSetNodeID &ID) const {
222  ID.AddPointer(Prefix.getOpaqueValue());
223  ID.AddPointer(Specifier);
224  }
225 
226  /// Dump the nested name specifier to standard output to aid
227  /// in debugging.
228  void dump(const LangOptions &LO) const;
229  void dump() const;
230  void dump(llvm::raw_ostream &OS) const;
231  void dump(llvm::raw_ostream &OS, const LangOptions &LO) const;
232 };
233 
234 /// A C++ nested-name-specifier augmented with source location
235 /// information.
237  NestedNameSpecifier *Qualifier = nullptr;
238  void *Data = nullptr;
239 
240  /// Determines the data length for the last component in the
241  /// given nested-name-specifier.
242  static unsigned getLocalDataLength(NestedNameSpecifier *Qualifier);
243 
244  /// Determines the data length for the entire
245  /// nested-name-specifier.
246  static unsigned getDataLength(NestedNameSpecifier *Qualifier);
247 
248 public:
249  /// Construct an empty nested-name-specifier.
250  NestedNameSpecifierLoc() = default;
251 
252  /// Construct a nested-name-specifier with source location information
253  /// from
255  : Qualifier(Qualifier), Data(Data) {}
256 
257  /// Evaluates true when this nested-name-specifier location is
258  /// non-empty.
259  explicit operator bool() const { return Qualifier; }
260 
261  /// Evaluates true when this nested-name-specifier location is
262  /// empty.
263  bool hasQualifier() const { return Qualifier; }
264 
265  /// Retrieve the nested-name-specifier to which this instance
266  /// refers.
268  return Qualifier;
269  }
270 
271  /// Retrieve the opaque pointer that refers to source-location data.
272  void *getOpaqueData() const { return Data; }
273 
274  /// Retrieve the source range covering the entirety of this
275  /// nested-name-specifier.
276  ///
277  /// For example, if this instance refers to a nested-name-specifier
278  /// \c \::std::vector<int>::, the returned source range would cover
279  /// from the initial '::' to the last '::'.
280  SourceRange getSourceRange() const LLVM_READONLY;
281 
282  /// Retrieve the source range covering just the last part of
283  /// this nested-name-specifier, not including the prefix.
284  ///
285  /// For example, if this instance refers to a nested-name-specifier
286  /// \c \::std::vector<int>::, the returned source range would cover
287  /// from "vector" to the last '::'.
288  SourceRange getLocalSourceRange() const;
289 
290  /// Retrieve the location of the beginning of this
291  /// nested-name-specifier.
293  return getSourceRange().getBegin();
294  }
295 
296  /// Retrieve the location of the end of this
297  /// nested-name-specifier.
299  return getSourceRange().getEnd();
300  }
301 
302  /// Retrieve the location of the beginning of this
303  /// component of the nested-name-specifier.
305  return getLocalSourceRange().getBegin();
306  }
307 
308  /// Retrieve the location of the end of this component of the
309  /// nested-name-specifier.
311  return getLocalSourceRange().getEnd();
312  }
313 
314  /// Return the prefix of this nested-name-specifier.
315  ///
316  /// For example, if this instance refers to a nested-name-specifier
317  /// \c \::std::vector<int>::, the prefix is \c \::std::. Note that the
318  /// returned prefix may be empty, if this is the first component of
319  /// the nested-name-specifier.
321  if (!Qualifier)
322  return *this;
323 
324  return NestedNameSpecifierLoc(Qualifier->getPrefix(), Data);
325  }
326 
327  /// For a nested-name-specifier that refers to a type,
328  /// retrieve the type with source-location information.
329  TypeLoc getTypeLoc() const;
330 
331  /// Determines the data length for the entire
332  /// nested-name-specifier.
333  unsigned getDataLength() const { return getDataLength(Qualifier); }
334 
337  return X.Qualifier == Y.Qualifier && X.Data == Y.Data;
338  }
339 
342  return !(X == Y);
343  }
344 };
345 
346 /// Class that aids in the construction of nested-name-specifiers along
347 /// with source-location information for all of the components of the
348 /// nested-name-specifier.
350  /// The current representation of the nested-name-specifier we're
351  /// building.
352  NestedNameSpecifier *Representation = nullptr;
353 
354  /// Buffer used to store source-location information for the
355  /// nested-name-specifier.
356  ///
357  /// Note that we explicitly manage the buffer (rather than using a
358  /// SmallVector) because \c Declarator expects it to be possible to memcpy()
359  /// a \c CXXScopeSpec, and CXXScopeSpec uses a NestedNameSpecifierLocBuilder.
360  char *Buffer = nullptr;
361 
362  /// The size of the buffer used to store source-location information
363  /// for the nested-name-specifier.
364  unsigned BufferSize = 0;
365 
366  /// The capacity of the buffer used to store source-location
367  /// information for the nested-name-specifier.
368  unsigned BufferCapacity = 0;
369 
370 public:
371  NestedNameSpecifierLocBuilder() = default;
373 
376 
378  if (BufferCapacity)
379  free(Buffer);
380  }
381 
382  /// Retrieve the representation of the nested-name-specifier.
383  NestedNameSpecifier *getRepresentation() const { return Representation; }
384 
385  /// Extend the current nested-name-specifier by another
386  /// nested-name-specifier component of the form 'type::'.
387  ///
388  /// \param Context The AST context in which this nested-name-specifier
389  /// resides.
390  ///
391  /// \param TemplateKWLoc The location of the 'template' keyword, if present.
392  ///
393  /// \param TL The TypeLoc that describes the type preceding the '::'.
394  ///
395  /// \param ColonColonLoc The location of the trailing '::'.
396  void Extend(ASTContext &Context, SourceLocation TemplateKWLoc, TypeLoc TL,
397  SourceLocation ColonColonLoc);
398 
399  /// Extend the current nested-name-specifier by another
400  /// nested-name-specifier component of the form 'identifier::'.
401  ///
402  /// \param Context The AST context in which this nested-name-specifier
403  /// resides.
404  ///
405  /// \param Identifier The identifier.
406  ///
407  /// \param IdentifierLoc The location of the identifier.
408  ///
409  /// \param ColonColonLoc The location of the trailing '::'.
410  void Extend(ASTContext &Context, IdentifierInfo *Identifier,
412 
413  /// Extend the current nested-name-specifier by another
414  /// nested-name-specifier component of the form 'namespace::'.
415  ///
416  /// \param Context The AST context in which this nested-name-specifier
417  /// resides.
418  ///
419  /// \param Namespace The namespace.
420  ///
421  /// \param NamespaceLoc The location of the namespace name.
422  ///
423  /// \param ColonColonLoc The location of the trailing '::'.
424  void Extend(ASTContext &Context, NamespaceDecl *Namespace,
425  SourceLocation NamespaceLoc, SourceLocation ColonColonLoc);
426 
427  /// Extend the current nested-name-specifier by another
428  /// nested-name-specifier component of the form 'namespace-alias::'.
429  ///
430  /// \param Context The AST context in which this nested-name-specifier
431  /// resides.
432  ///
433  /// \param Alias The namespace alias.
434  ///
435  /// \param AliasLoc The location of the namespace alias
436  /// name.
437  ///
438  /// \param ColonColonLoc The location of the trailing '::'.
439  void Extend(ASTContext &Context, NamespaceAliasDecl *Alias,
440  SourceLocation AliasLoc, SourceLocation ColonColonLoc);
441 
442  /// Turn this (empty) nested-name-specifier into the global
443  /// nested-name-specifier '::'.
444  void MakeGlobal(ASTContext &Context, SourceLocation ColonColonLoc);
445 
446  /// Turns this (empty) nested-name-specifier into '__super'
447  /// nested-name-specifier.
448  ///
449  /// \param Context The AST context in which this nested-name-specifier
450  /// resides.
451  ///
452  /// \param RD The declaration of the class in which nested-name-specifier
453  /// appeared.
454  ///
455  /// \param SuperLoc The location of the '__super' keyword.
456  /// name.
457  ///
458  /// \param ColonColonLoc The location of the trailing '::'.
459  void MakeSuper(ASTContext &Context, CXXRecordDecl *RD,
460  SourceLocation SuperLoc, SourceLocation ColonColonLoc);
461 
462  /// Make a new nested-name-specifier from incomplete source-location
463  /// information.
464  ///
465  /// This routine should be used very, very rarely, in cases where we
466  /// need to synthesize a nested-name-specifier. Most code should instead use
467  /// \c Adopt() with a proper \c NestedNameSpecifierLoc.
468  void MakeTrivial(ASTContext &Context, NestedNameSpecifier *Qualifier,
469  SourceRange R);
470 
471  /// Adopt an existing nested-name-specifier (with source-range
472  /// information).
473  void Adopt(NestedNameSpecifierLoc Other);
474 
475  /// Retrieve the source range covered by this nested-name-specifier.
476  SourceRange getSourceRange() const LLVM_READONLY {
477  return NestedNameSpecifierLoc(Representation, Buffer).getSourceRange();
478  }
479 
480  /// Retrieve a nested-name-specifier with location information,
481  /// copied into the given AST context.
482  ///
483  /// \param Context The context into which this nested-name-specifier will be
484  /// copied.
485  NestedNameSpecifierLoc getWithLocInContext(ASTContext &Context) const;
486 
487  /// Retrieve a nested-name-specifier with location
488  /// information based on the information in this builder.
489  ///
490  /// This loc will contain references to the builder's internal data and may
491  /// be invalidated by any change to the builder.
493  return NestedNameSpecifierLoc(Representation, Buffer);
494  }
495 
496  /// Clear out this builder, and prepare it to build another
497  /// nested-name-specifier with source-location information.
498  void Clear() {
499  Representation = nullptr;
500  BufferSize = 0;
501  }
502 
503  /// Retrieve the underlying buffer.
504  ///
505  /// \returns A pair containing a pointer to the buffer of source-location
506  /// data and the size of the source-location data that resides in that
507  /// buffer.
508  std::pair<char *, unsigned> getBuffer() const {
509  return std::make_pair(Buffer, BufferSize);
510  }
511 };
512 
513 /// Insertion operator for diagnostics. This allows sending
514 /// NestedNameSpecifiers into a diagnostic with <<.
516  NestedNameSpecifier *NNS) {
517  DB.AddTaggedVal(reinterpret_cast<intptr_t>(NNS),
519  return DB;
520 }
521 
522 } // namespace clang
523 
524 #endif // LLVM_CLANG_AST_NESTEDNAMESPECIFIER_H
SourceRange getSourceRange() const LLVM_READONLY
Retrieve the source range covering the entirety of this nested-name-specifier.
Microsoft&#39;s &#39;__super&#39; specifier, stored as a CXXRecordDecl* of the class it appeared in...
friend bool operator!=(NestedNameSpecifierLoc X, NestedNameSpecifierLoc Y)
NestedNameSpecifier * getPrefix() const
Return the prefix of this nested name specifier.
const DiagnosticBuilder & operator<<(const DiagnosticBuilder &DB, const Attr *At)
Definition: Attr.h:335
The base class of the type hierarchy.
Definition: Type.h:1414
NestedNameSpecifierLoc getTemporary() const
Retrieve a nested-name-specifier with location information based on the information in this builder...
Represent a C++ namespace.
Definition: Decl.h:514
void Profile(llvm::FoldingSetNodeID &ID) const
SourceLocation getLocalBeginLoc() const
Retrieve the location of the beginning of this component of the nested-name-specifier.
NestedNameSpecifier & operator=(const NestedNameSpecifier &)=delete
An identifier, stored as an IdentifierInfo*.
std::pair< char *, unsigned > getBuffer() const
Retrieve the underlying buffer.
static NestedNameSpecifier * Create(const ASTContext &Context, NestedNameSpecifier *Prefix, IdentifierInfo *II)
Builds a specifier combining a prefix and an identifier.
A namespace, stored as a NamespaceDecl*.
Describes how types, statements, expressions, and declarations should be printed. ...
Definition: PrettyPrinter.h:37
SpecifierKind getKind() const
Determine what kind of nested name specifier is stored.
CharSourceRange getSourceRange(const SourceRange &Range)
Returns the token CharSourceRange corresponding to Range.
Definition: FixIt.h:33
bool hasQualifier() const
Evaluates true when this nested-name-specifier location is empty.
Base wrapper for a particular "section" of type source info.
Definition: TypeLoc.h:56
void AddTaggedVal(intptr_t V, DiagnosticsEngine::ArgumentKind Kind) const
Definition: Diagnostic.h:1157
One of these records is kept for each identifier that is lexed.
SourceLocation getBegin() const
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:154
A C++ nested-name-specifier augmented with source location information.
const Type * getAsType() const
Retrieve the type stored in this nested name specifier.
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:49
friend bool operator==(NestedNameSpecifierLoc X, NestedNameSpecifierLoc Y)
CXXRecordDecl * getAsRecordDecl() const
Retrieve the record declaration stored in this nested name specifier.
IdentifierInfo * getAsIdentifier() const
Retrieve the identifier stored in this nested name specifier.
NamespaceAliasDecl * getAsNamespaceAlias() const
Retrieve the namespace alias stored in this nested name specifier.
Defines the Diagnostic-related interfaces.
SourceLocation getLocalEndLoc() const
Retrieve the location of the end of this component of the nested-name-specifier.
void print(raw_ostream &OS, const PrintingPolicy &Policy, bool ResolveTemplateArguments=false) const
Print this nested name specifier to the given output stream.
Class that aids in the construction of nested-name-specifiers along with source-location information ...
SourceRange getSourceRange() const LLVM_READONLY
Retrieve the source range covered by this nested-name-specifier.
bool isInstantiationDependent() const
Whether this nested name specifier involves a template parameter.
A little helper class used to produce diagnostics.
Definition: Diagnostic.h:1044
static NestedNameSpecifier * SuperSpecifier(const ASTContext &Context, CXXRecordDecl *RD)
Returns the nested name specifier representing the __super scope for the given CXXRecordDecl.
NamespaceDecl * getAsNamespace() const
Retrieve the namespace stored in this nested name specifier.
SourceLocation getBeginLoc() const
Retrieve the location of the beginning of this nested-name-specifier.
#define bool
Definition: stdbool.h:31
NestedNameSpecifierLoc getPrefix() const
Return the prefix of this nested-name-specifier.
A namespace alias, stored as a NamespaceAliasDecl*.
SourceLocation getEnd() const
Wraps an identifier and optional source location for the identifier.
Definition: ParsedAttr.h:94
SpecifierKind
The kind of specifier that completes this nested name specifier.
bool containsUnexpandedParameterPack() const
Whether this nested-name-specifier contains an unexpanded parameter pack (for C++11 variadic template...
Encodes a location in the source.
NestedNameSpecifier * getRepresentation() const
Retrieve the representation of the nested-name-specifier.
Represents a C++ nested name specifier, such as "\::std::vector<int>::".
NestedNameSpecifierLoc(NestedNameSpecifier *Qualifier, void *Data)
Construct a nested-name-specifier with source location information from.
Optional< types::ID > Type
Dataflow Directional Tag Classes.
NestedNameSpecifier * getNestedNameSpecifier() const
Retrieve the nested-name-specifier to which this instance refers.
unsigned getDataLength() const
Determines the data length for the entire nested-name-specifier.
bool isDependent() const
Whether this nested name specifier refers to a dependent type or not.
A type that was preceded by the &#39;template&#39; keyword, stored as a Type*.
SourceLocation getEndLoc() const
Retrieve the location of the end of this nested-name-specifier.
SourceLocation getEnd() const
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:14015
void * getOpaqueData() const
Retrieve the opaque pointer that refers to source-location data.
Defines the clang::SourceLocation class and associated facilities.
Represents a C++ struct/union/class.
Definition: DeclCXX.h:299
A trivial tuple used to represent a source range.
Represents a C++ namespace alias.
Definition: DeclCXX.h:3027
The global specifier &#39;::&#39;. There is no stored value.
SourceLocation getBegin() const
void Clear()
Clear out this builder, and prepare it to build another nested-name-specifier with source-location in...
static NestedNameSpecifier * GlobalSpecifier(const ASTContext &Context)
Returns the nested name specifier representing the global scope.