1//===--- NestedNameSpecifier.h - C++ nested name specifiers -----*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file defines the NestedNameSpecifier class, which represents
11//  a C++ nested-name-specifier.
12//
13//===----------------------------------------------------------------------===//
14#ifndef LLVM_CLANG_AST_NESTEDNAMESPECIFIER_H
15#define LLVM_CLANG_AST_NESTEDNAMESPECIFIER_H
16
17#include "clang/Basic/Diagnostic.h"
18#include "llvm/ADT/FoldingSet.h"
19#include "llvm/ADT/PointerIntPair.h"
20#include "llvm/Support/Compiler.h"
21
22namespace clang {
23
24class ASTContext;
25class CXXRecordDecl;
26class NamespaceAliasDecl;
27class NamespaceDecl;
28class IdentifierInfo;
29struct PrintingPolicy;
30class Type;
31class TypeLoc;
32class LangOptions;
33
34/// \brief Represents a C++ nested name specifier, such as
35/// "\::std::vector<int>::".
36///
37/// C++ nested name specifiers are the prefixes to qualified
38/// namespaces. For example, "foo::" in "foo::x" is a nested name
39/// specifier. Nested name specifiers are made up of a sequence of
40/// specifiers, each of which can be a namespace, type, identifier
41/// (for dependent names), decltype specifier, or the global specifier ('::').
42/// The last two specifiers can only appear at the start of a
43/// nested-namespace-specifier.
44class NestedNameSpecifier : public llvm::FoldingSetNode {
45
46  /// \brief Enumeration describing
47  enum StoredSpecifierKind {
48    StoredIdentifier = 0,
49    StoredDecl = 1,
50    StoredTypeSpec = 2,
51    StoredTypeSpecWithTemplate = 3
52  };
53
54  /// \brief The nested name specifier that precedes this nested name
55  /// specifier.
56  ///
57  /// The pointer is the nested-name-specifier that precedes this
58  /// one. The integer stores one of the first four values of type
59  /// SpecifierKind.
60  llvm::PointerIntPair<NestedNameSpecifier *, 2, StoredSpecifierKind> Prefix;
61
62  /// \brief The last component in the nested name specifier, which
63  /// can be an identifier, a declaration, or a type.
64  ///
65  /// When the pointer is NULL, this specifier represents the global
66  /// specifier '::'. Otherwise, the pointer is one of
67  /// IdentifierInfo*, Namespace*, or Type*, depending on the kind of
68  /// specifier as encoded within the prefix.
69  void* Specifier;
70
71public:
72  /// \brief The kind of specifier that completes this nested name
73  /// specifier.
74  enum SpecifierKind {
75    /// \brief An identifier, stored as an IdentifierInfo*.
76    Identifier,
77    /// \brief A namespace, stored as a NamespaceDecl*.
78    Namespace,
79    /// \brief A namespace alias, stored as a NamespaceAliasDecl*.
80    NamespaceAlias,
81    /// \brief A type, stored as a Type*.
82    TypeSpec,
83    /// \brief A type that was preceded by the 'template' keyword,
84    /// stored as a Type*.
85    TypeSpecWithTemplate,
86    /// \brief The global specifier '::'. There is no stored value.
87    Global,
88    /// \brief Microsoft's '__super' specifier, stored as a CXXRecordDecl* of
89    /// the class it appeared in.
90    Super
91  };
92
93private:
94  /// \brief Builds the global specifier.
95  NestedNameSpecifier()
96    : Prefix(nullptr, StoredIdentifier), Specifier(nullptr) {}
97
98  /// \brief Copy constructor used internally to clone nested name
99  /// specifiers.
100  NestedNameSpecifier(const NestedNameSpecifier &Other)
101    : llvm::FoldingSetNode(Other), Prefix(Other.Prefix),
102      Specifier(Other.Specifier) {
103  }
104
105  void operator=(const NestedNameSpecifier &) = delete;
106
107  /// \brief Either find or insert the given nested name specifier
108  /// mockup in the given context.
109  static NestedNameSpecifier *FindOrInsert(const ASTContext &Context,
110                                           const NestedNameSpecifier &Mockup);
111
112public:
113  /// \brief Builds a specifier combining a prefix and an identifier.
114  ///
115  /// The prefix must be dependent, since nested name specifiers
116  /// referencing an identifier are only permitted when the identifier
117  /// cannot be resolved.
118  static NestedNameSpecifier *Create(const ASTContext &Context,
119                                     NestedNameSpecifier *Prefix,
120                                     IdentifierInfo *II);
121
122  /// \brief Builds a nested name specifier that names a namespace.
123  static NestedNameSpecifier *Create(const ASTContext &Context,
124                                     NestedNameSpecifier *Prefix,
125                                     const NamespaceDecl *NS);
126
127  /// \brief Builds a nested name specifier that names a namespace alias.
128  static NestedNameSpecifier *Create(const ASTContext &Context,
129                                     NestedNameSpecifier *Prefix,
130                                     NamespaceAliasDecl *Alias);
131
132  /// \brief Builds a nested name specifier that names a type.
133  static NestedNameSpecifier *Create(const ASTContext &Context,
134                                     NestedNameSpecifier *Prefix,
135                                     bool Template, const Type *T);
136
137  /// \brief Builds a specifier that consists of just an identifier.
138  ///
139  /// The nested-name-specifier is assumed to be dependent, but has no
140  /// prefix because the prefix is implied by something outside of the
141  /// nested name specifier, e.g., in "x->Base::f", the "x" has a dependent
142  /// type.
143  static NestedNameSpecifier *Create(const ASTContext &Context,
144                                     IdentifierInfo *II);
145
146  /// \brief Returns the nested name specifier representing the global
147  /// scope.
148  static NestedNameSpecifier *GlobalSpecifier(const ASTContext &Context);
149
150  /// \brief Returns the nested name specifier representing the __super scope
151  /// for the given CXXRecordDecl.
152  static NestedNameSpecifier *SuperSpecifier(const ASTContext &Context,
153                                             CXXRecordDecl *RD);
154
155  /// \brief Return the prefix of this nested name specifier.
156  ///
157  /// The prefix contains all of the parts of the nested name
158  /// specifier that preced this current specifier. For example, for a
159  /// nested name specifier that represents "foo::bar::", the current
160  /// specifier will contain "bar::" and the prefix will contain
161  /// "foo::".
162  NestedNameSpecifier *getPrefix() const { return Prefix.getPointer(); }
163
164  /// \brief Determine what kind of nested name specifier is stored.
165  SpecifierKind getKind() const;
166
167  /// \brief Retrieve the identifier stored in this nested name
168  /// specifier.
169  IdentifierInfo *getAsIdentifier() const {
170    if (Prefix.getInt() == StoredIdentifier)
171      return (IdentifierInfo *)Specifier;
172
173    return nullptr;
174  }
175
176  /// \brief Retrieve the namespace stored in this nested name
177  /// specifier.
178  NamespaceDecl *getAsNamespace() const;
179
180  /// \brief Retrieve the namespace alias stored in this nested name
181  /// specifier.
182  NamespaceAliasDecl *getAsNamespaceAlias() const;
183
184  /// \brief Retrieve the record declaration stored in this nested name
185  /// specifier.
186  CXXRecordDecl *getAsRecordDecl() const;
187
188  /// \brief Retrieve the type stored in this nested name specifier.
189  const Type *getAsType() const {
190    if (Prefix.getInt() == StoredTypeSpec ||
191        Prefix.getInt() == StoredTypeSpecWithTemplate)
192      return (const Type *)Specifier;
193
194    return nullptr;
195  }
196
197  /// \brief Whether this nested name specifier refers to a dependent
198  /// type or not.
199  bool isDependent() const;
200
201  /// \brief Whether this nested name specifier involves a template
202  /// parameter.
203  bool isInstantiationDependent() const;
204
205  /// \brief Whether this nested-name-specifier contains an unexpanded
206  /// parameter pack (for C++11 variadic templates).
207  bool containsUnexpandedParameterPack() const;
208
209  /// \brief Print this nested name specifier to the given output
210  /// stream.
211  void print(raw_ostream &OS, const PrintingPolicy &Policy) const;
212
213  void Profile(llvm::FoldingSetNodeID &ID) const {
214    ID.AddPointer(Prefix.getOpaqueValue());
215    ID.AddPointer(Specifier);
216  }
217
218  /// \brief Dump the nested name specifier to standard output to aid
219  /// in debugging.
220  void dump(const LangOptions &LO) const;
221  void dump() const;
222};
223
224/// \brief A C++ nested-name-specifier augmented with source location
225/// information.
226class NestedNameSpecifierLoc {
227  NestedNameSpecifier *Qualifier;
228  void *Data;
229
230  /// \brief Determines the data length for the last component in the
231  /// given nested-name-specifier.
232  static unsigned getLocalDataLength(NestedNameSpecifier *Qualifier);
233
234  /// \brief Determines the data length for the entire
235  /// nested-name-specifier.
236  static unsigned getDataLength(NestedNameSpecifier *Qualifier);
237
238public:
239  /// \brief Construct an empty nested-name-specifier.
240  NestedNameSpecifierLoc() : Qualifier(nullptr), Data(nullptr) { }
241
242  /// \brief Construct a nested-name-specifier with source location information
243  /// from
244  NestedNameSpecifierLoc(NestedNameSpecifier *Qualifier, void *Data)
245    : Qualifier(Qualifier), Data(Data) { }
246
247  /// \brief Evalutes true when this nested-name-specifier location is
248  /// non-empty.
249  explicit operator bool() const { return Qualifier; }
250
251  /// \brief Evalutes true when this nested-name-specifier location is
252  /// empty.
253  bool hasQualifier() const { return Qualifier; }
254
255  /// \brief Retrieve the nested-name-specifier to which this instance
256  /// refers.
257  NestedNameSpecifier *getNestedNameSpecifier() const {
258    return Qualifier;
259  }
260
261  /// \brief Retrieve the opaque pointer that refers to source-location data.
262  void *getOpaqueData() const { return Data; }
263
264  /// \brief Retrieve the source range covering the entirety of this
265  /// nested-name-specifier.
266  ///
267  /// For example, if this instance refers to a nested-name-specifier
268  /// \c \::std::vector<int>::, the returned source range would cover
269  /// from the initial '::' to the last '::'.
270  SourceRange getSourceRange() const LLVM_READONLY;
271
272  /// \brief Retrieve the source range covering just the last part of
273  /// this nested-name-specifier, not including the prefix.
274  ///
275  /// For example, if this instance refers to a nested-name-specifier
276  /// \c \::std::vector<int>::, the returned source range would cover
277  /// from "vector" to the last '::'.
278  SourceRange getLocalSourceRange() const;
279
280  /// \brief Retrieve the location of the beginning of this
281  /// nested-name-specifier.
282  SourceLocation getBeginLoc() const {
283    return getSourceRange().getBegin();
284  }
285
286  /// \brief Retrieve the location of the end of this
287  /// nested-name-specifier.
288  SourceLocation getEndLoc() const {
289    return getSourceRange().getEnd();
290  }
291
292  /// \brief Retrieve the location of the beginning of this
293  /// component of the nested-name-specifier.
294  SourceLocation getLocalBeginLoc() const {
295    return getLocalSourceRange().getBegin();
296  }
297
298  /// \brief Retrieve the location of the end of this component of the
299  /// nested-name-specifier.
300  SourceLocation getLocalEndLoc() const {
301    return getLocalSourceRange().getEnd();
302  }
303
304  /// \brief Return the prefix of this nested-name-specifier.
305  ///
306  /// For example, if this instance refers to a nested-name-specifier
307  /// \c \::std::vector<int>::, the prefix is \c \::std::. Note that the
308  /// returned prefix may be empty, if this is the first component of
309  /// the nested-name-specifier.
310  NestedNameSpecifierLoc getPrefix() const {
311    if (!Qualifier)
312      return *this;
313
314    return NestedNameSpecifierLoc(Qualifier->getPrefix(), Data);
315  }
316
317  /// \brief For a nested-name-specifier that refers to a type,
318  /// retrieve the type with source-location information.
319  TypeLoc getTypeLoc() const;
320
321  /// \brief Determines the data length for the entire
322  /// nested-name-specifier.
323  unsigned getDataLength() const { return getDataLength(Qualifier); }
324
325  friend bool operator==(NestedNameSpecifierLoc X,
326                         NestedNameSpecifierLoc Y) {
327    return X.Qualifier == Y.Qualifier && X.Data == Y.Data;
328  }
329
330  friend bool operator!=(NestedNameSpecifierLoc X,
331                         NestedNameSpecifierLoc Y) {
332    return !(X == Y);
333  }
334};
335
336/// \brief Class that aids in the construction of nested-name-specifiers along
337/// with source-location information for all of the components of the
338/// nested-name-specifier.
339class NestedNameSpecifierLocBuilder {
340  /// \brief The current representation of the nested-name-specifier we're
341  /// building.
342  NestedNameSpecifier *Representation;
343
344  /// \brief Buffer used to store source-location information for the
345  /// nested-name-specifier.
346  ///
347  /// Note that we explicitly manage the buffer (rather than using a
348  /// SmallVector) because \c Declarator expects it to be possible to memcpy()
349  /// a \c CXXScopeSpec, and CXXScopeSpec uses a NestedNameSpecifierLocBuilder.
350  char *Buffer;
351
352  /// \brief The size of the buffer used to store source-location information
353  /// for the nested-name-specifier.
354  unsigned BufferSize;
355
356  /// \brief The capacity of the buffer used to store source-location
357  /// information for the nested-name-specifier.
358  unsigned BufferCapacity;
359
360public:
361  NestedNameSpecifierLocBuilder()
362    : Representation(nullptr), Buffer(nullptr), BufferSize(0),
363      BufferCapacity(0) {}
364
365  NestedNameSpecifierLocBuilder(const NestedNameSpecifierLocBuilder &Other);
366
367  NestedNameSpecifierLocBuilder &
368  operator=(const NestedNameSpecifierLocBuilder &Other);
369
370  ~NestedNameSpecifierLocBuilder() {
371    if (BufferCapacity)
372      free(Buffer);
373  }
374
375  /// \brief Retrieve the representation of the nested-name-specifier.
376  NestedNameSpecifier *getRepresentation() const { return Representation; }
377
378  /// \brief Extend the current nested-name-specifier by another
379  /// nested-name-specifier component of the form 'type::'.
380  ///
381  /// \param Context The AST context in which this nested-name-specifier
382  /// resides.
383  ///
384  /// \param TemplateKWLoc The location of the 'template' keyword, if present.
385  ///
386  /// \param TL The TypeLoc that describes the type preceding the '::'.
387  ///
388  /// \param ColonColonLoc The location of the trailing '::'.
389  void Extend(ASTContext &Context, SourceLocation TemplateKWLoc, TypeLoc TL,
390              SourceLocation ColonColonLoc);
391
392  /// \brief Extend the current nested-name-specifier by another
393  /// nested-name-specifier component of the form 'identifier::'.
394  ///
395  /// \param Context The AST context in which this nested-name-specifier
396  /// resides.
397  ///
398  /// \param Identifier The identifier.
399  ///
400  /// \param IdentifierLoc The location of the identifier.
401  ///
402  /// \param ColonColonLoc The location of the trailing '::'.
403  void Extend(ASTContext &Context, IdentifierInfo *Identifier,
404              SourceLocation IdentifierLoc, SourceLocation ColonColonLoc);
405
406  /// \brief Extend the current nested-name-specifier by another
407  /// nested-name-specifier component of the form 'namespace::'.
408  ///
409  /// \param Context The AST context in which this nested-name-specifier
410  /// resides.
411  ///
412  /// \param Namespace The namespace.
413  ///
414  /// \param NamespaceLoc The location of the namespace name.
415  ///
416  /// \param ColonColonLoc The location of the trailing '::'.
417  void Extend(ASTContext &Context, NamespaceDecl *Namespace,
418              SourceLocation NamespaceLoc, SourceLocation ColonColonLoc);
419
420  /// \brief Extend the current nested-name-specifier by another
421  /// nested-name-specifier component of the form 'namespace-alias::'.
422  ///
423  /// \param Context The AST context in which this nested-name-specifier
424  /// resides.
425  ///
426  /// \param Alias The namespace alias.
427  ///
428  /// \param AliasLoc The location of the namespace alias
429  /// name.
430  ///
431  /// \param ColonColonLoc The location of the trailing '::'.
432  void Extend(ASTContext &Context, NamespaceAliasDecl *Alias,
433              SourceLocation AliasLoc, SourceLocation ColonColonLoc);
434
435  /// \brief Turn this (empty) nested-name-specifier into the global
436  /// nested-name-specifier '::'.
437  void MakeGlobal(ASTContext &Context, SourceLocation ColonColonLoc);
438
439  /// \brief Turns this (empty) nested-name-specifier into '__super'
440  /// nested-name-specifier.
441  ///
442  /// \param Context The AST context in which this nested-name-specifier
443  /// resides.
444  ///
445  /// \param RD The declaration of the class in which nested-name-specifier
446  /// appeared.
447  ///
448  /// \param SuperLoc The location of the '__super' keyword.
449  /// name.
450  ///
451  /// \param ColonColonLoc The location of the trailing '::'.
452  void MakeSuper(ASTContext &Context, CXXRecordDecl *RD,
453                 SourceLocation SuperLoc, SourceLocation ColonColonLoc);
454  /// \brief Make a new nested-name-specifier from incomplete source-location
455  /// information.
456  ///
457  /// This routine should be used very, very rarely, in cases where we
458  /// need to synthesize a nested-name-specifier. Most code should instead use
459  /// \c Adopt() with a proper \c NestedNameSpecifierLoc.
460  void MakeTrivial(ASTContext &Context, NestedNameSpecifier *Qualifier,
461                   SourceRange R);
462
463  /// \brief Adopt an existing nested-name-specifier (with source-range
464  /// information).
465  void Adopt(NestedNameSpecifierLoc Other);
466
467  /// \brief Retrieve the source range covered by this nested-name-specifier.
468  SourceRange getSourceRange() const LLVM_READONLY {
469    return NestedNameSpecifierLoc(Representation, Buffer).getSourceRange();
470  }
471
472  /// \brief Retrieve a nested-name-specifier with location information,
473  /// copied into the given AST context.
474  ///
475  /// \param Context The context into which this nested-name-specifier will be
476  /// copied.
477  NestedNameSpecifierLoc getWithLocInContext(ASTContext &Context) const;
478
479  /// \brief Retrieve a nested-name-specifier with location
480  /// information based on the information in this builder.
481  ///
482  /// This loc will contain references to the builder's internal data and may
483  /// be invalidated by any change to the builder.
484  NestedNameSpecifierLoc getTemporary() const {
485    return NestedNameSpecifierLoc(Representation, Buffer);
486  }
487
488  /// \brief Clear out this builder, and prepare it to build another
489  /// nested-name-specifier with source-location information.
490  void Clear() {
491    Representation = nullptr;
492    BufferSize = 0;
493  }
494
495  /// \brief Retrieve the underlying buffer.
496  ///
497  /// \returns A pair containing a pointer to the buffer of source-location
498  /// data and the size of the source-location data that resides in that
499  /// buffer.
500  std::pair<char *, unsigned> getBuffer() const {
501    return std::make_pair(Buffer, BufferSize);
502  }
503};
504
505/// Insertion operator for diagnostics.  This allows sending
506/// NestedNameSpecifiers into a diagnostic with <<.
507inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
508                                           NestedNameSpecifier *NNS) {
509  DB.AddTaggedVal(reinterpret_cast<intptr_t>(NNS),
510                  DiagnosticsEngine::ak_nestednamespec);
511  return DB;
512}
513
514}
515
516#endif
517