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);
221};
222
223/// \brief A C++ nested-name-specifier augmented with source location
224/// information.
225class NestedNameSpecifierLoc {
226  NestedNameSpecifier *Qualifier;
227  void *Data;
228
229  /// \brief Determines the data length for the last component in the
230  /// given nested-name-specifier.
231  static unsigned getLocalDataLength(NestedNameSpecifier *Qualifier);
232
233  /// \brief Determines the data length for the entire
234  /// nested-name-specifier.
235  static unsigned getDataLength(NestedNameSpecifier *Qualifier);
236
237public:
238  /// \brief Construct an empty nested-name-specifier.
239  NestedNameSpecifierLoc() : Qualifier(nullptr), Data(nullptr) { }
240
241  /// \brief Construct a nested-name-specifier with source location information
242  /// from
243  NestedNameSpecifierLoc(NestedNameSpecifier *Qualifier, void *Data)
244    : Qualifier(Qualifier), Data(Data) { }
245
246  /// \brief Evalutes true when this nested-name-specifier location is
247  /// non-empty.
248  explicit operator bool() const { return Qualifier; }
249
250  /// \brief Evalutes true when this nested-name-specifier location is
251  /// empty.
252  bool hasQualifier() const { return Qualifier; }
253
254  /// \brief Retrieve the nested-name-specifier to which this instance
255  /// refers.
256  NestedNameSpecifier *getNestedNameSpecifier() const {
257    return Qualifier;
258  }
259
260  /// \brief Retrieve the opaque pointer that refers to source-location data.
261  void *getOpaqueData() const { return Data; }
262
263  /// \brief Retrieve the source range covering the entirety of this
264  /// nested-name-specifier.
265  ///
266  /// For example, if this instance refers to a nested-name-specifier
267  /// \c \::std::vector<int>::, the returned source range would cover
268  /// from the initial '::' to the last '::'.
269  SourceRange getSourceRange() const LLVM_READONLY;
270
271  /// \brief Retrieve the source range covering just the last part of
272  /// this nested-name-specifier, not including the prefix.
273  ///
274  /// For example, if this instance refers to a nested-name-specifier
275  /// \c \::std::vector<int>::, the returned source range would cover
276  /// from "vector" to the last '::'.
277  SourceRange getLocalSourceRange() const;
278
279  /// \brief Retrieve the location of the beginning of this
280  /// nested-name-specifier.
281  SourceLocation getBeginLoc() const {
282    return getSourceRange().getBegin();
283  }
284
285  /// \brief Retrieve the location of the end of this
286  /// nested-name-specifier.
287  SourceLocation getEndLoc() const {
288    return getSourceRange().getEnd();
289  }
290
291  /// \brief Retrieve the location of the beginning of this
292  /// component of the nested-name-specifier.
293  SourceLocation getLocalBeginLoc() const {
294    return getLocalSourceRange().getBegin();
295  }
296
297  /// \brief Retrieve the location of the end of this component of the
298  /// nested-name-specifier.
299  SourceLocation getLocalEndLoc() const {
300    return getLocalSourceRange().getEnd();
301  }
302
303  /// \brief Return the prefix of this nested-name-specifier.
304  ///
305  /// For example, if this instance refers to a nested-name-specifier
306  /// \c \::std::vector<int>::, the prefix is \c \::std::. Note that the
307  /// returned prefix may be empty, if this is the first component of
308  /// the nested-name-specifier.
309  NestedNameSpecifierLoc getPrefix() const {
310    if (!Qualifier)
311      return *this;
312
313    return NestedNameSpecifierLoc(Qualifier->getPrefix(), Data);
314  }
315
316  /// \brief For a nested-name-specifier that refers to a type,
317  /// retrieve the type with source-location information.
318  TypeLoc getTypeLoc() const;
319
320  /// \brief Determines the data length for the entire
321  /// nested-name-specifier.
322  unsigned getDataLength() const { return getDataLength(Qualifier); }
323
324  friend bool operator==(NestedNameSpecifierLoc X,
325                         NestedNameSpecifierLoc Y) {
326    return X.Qualifier == Y.Qualifier && X.Data == Y.Data;
327  }
328
329  friend bool operator!=(NestedNameSpecifierLoc X,
330                         NestedNameSpecifierLoc Y) {
331    return !(X == Y);
332  }
333};
334
335/// \brief Class that aids in the construction of nested-name-specifiers along
336/// with source-location information for all of the components of the
337/// nested-name-specifier.
338class NestedNameSpecifierLocBuilder {
339  /// \brief The current representation of the nested-name-specifier we're
340  /// building.
341  NestedNameSpecifier *Representation;
342
343  /// \brief Buffer used to store source-location information for the
344  /// nested-name-specifier.
345  ///
346  /// Note that we explicitly manage the buffer (rather than using a
347  /// SmallVector) because \c Declarator expects it to be possible to memcpy()
348  /// a \c CXXScopeSpec, and CXXScopeSpec uses a NestedNameSpecifierLocBuilder.
349  char *Buffer;
350
351  /// \brief The size of the buffer used to store source-location information
352  /// for the nested-name-specifier.
353  unsigned BufferSize;
354
355  /// \brief The capacity of the buffer used to store source-location
356  /// information for the nested-name-specifier.
357  unsigned BufferCapacity;
358
359public:
360  NestedNameSpecifierLocBuilder()
361    : Representation(nullptr), Buffer(nullptr), BufferSize(0),
362      BufferCapacity(0) {}
363
364  NestedNameSpecifierLocBuilder(const NestedNameSpecifierLocBuilder &Other);
365
366  NestedNameSpecifierLocBuilder &
367  operator=(const NestedNameSpecifierLocBuilder &Other);
368
369  ~NestedNameSpecifierLocBuilder() {
370    if (BufferCapacity)
371      free(Buffer);
372  }
373
374  /// \brief Retrieve the representation of the nested-name-specifier.
375  NestedNameSpecifier *getRepresentation() const { return Representation; }
376
377  /// \brief Extend the current nested-name-specifier by another
378  /// nested-name-specifier component of the form 'type::'.
379  ///
380  /// \param Context The AST context in which this nested-name-specifier
381  /// resides.
382  ///
383  /// \param TemplateKWLoc The location of the 'template' keyword, if present.
384  ///
385  /// \param TL The TypeLoc that describes the type preceding the '::'.
386  ///
387  /// \param ColonColonLoc The location of the trailing '::'.
388  void Extend(ASTContext &Context, SourceLocation TemplateKWLoc, TypeLoc TL,
389              SourceLocation ColonColonLoc);
390
391  /// \brief Extend the current nested-name-specifier by another
392  /// nested-name-specifier component of the form 'identifier::'.
393  ///
394  /// \param Context The AST context in which this nested-name-specifier
395  /// resides.
396  ///
397  /// \param Identifier The identifier.
398  ///
399  /// \param IdentifierLoc The location of the identifier.
400  ///
401  /// \param ColonColonLoc The location of the trailing '::'.
402  void Extend(ASTContext &Context, IdentifierInfo *Identifier,
403              SourceLocation IdentifierLoc, SourceLocation ColonColonLoc);
404
405  /// \brief Extend the current nested-name-specifier by another
406  /// nested-name-specifier component of the form 'namespace::'.
407  ///
408  /// \param Context The AST context in which this nested-name-specifier
409  /// resides.
410  ///
411  /// \param Namespace The namespace.
412  ///
413  /// \param NamespaceLoc The location of the namespace name.
414  ///
415  /// \param ColonColonLoc The location of the trailing '::'.
416  void Extend(ASTContext &Context, NamespaceDecl *Namespace,
417              SourceLocation NamespaceLoc, SourceLocation ColonColonLoc);
418
419  /// \brief Extend the current nested-name-specifier by another
420  /// nested-name-specifier component of the form 'namespace-alias::'.
421  ///
422  /// \param Context The AST context in which this nested-name-specifier
423  /// resides.
424  ///
425  /// \param Alias The namespace alias.
426  ///
427  /// \param AliasLoc The location of the namespace alias
428  /// name.
429  ///
430  /// \param ColonColonLoc The location of the trailing '::'.
431  void Extend(ASTContext &Context, NamespaceAliasDecl *Alias,
432              SourceLocation AliasLoc, SourceLocation ColonColonLoc);
433
434  /// \brief Turn this (empty) nested-name-specifier into the global
435  /// nested-name-specifier '::'.
436  void MakeGlobal(ASTContext &Context, SourceLocation ColonColonLoc);
437
438  /// \brief Turns this (empty) nested-name-specifier into '__super'
439  /// nested-name-specifier.
440  ///
441  /// \param Context The AST context in which this nested-name-specifier
442  /// resides.
443  ///
444  /// \param RD The declaration of the class in which nested-name-specifier
445  /// appeared.
446  ///
447  /// \param SuperLoc The location of the '__super' keyword.
448  /// name.
449  ///
450  /// \param ColonColonLoc The location of the trailing '::'.
451  void MakeSuper(ASTContext &Context, CXXRecordDecl *RD,
452                 SourceLocation SuperLoc, SourceLocation ColonColonLoc);
453  /// \brief Make a new nested-name-specifier from incomplete source-location
454  /// information.
455  ///
456  /// This routine should be used very, very rarely, in cases where we
457  /// need to synthesize a nested-name-specifier. Most code should instead use
458  /// \c Adopt() with a proper \c NestedNameSpecifierLoc.
459  void MakeTrivial(ASTContext &Context, NestedNameSpecifier *Qualifier,
460                   SourceRange R);
461
462  /// \brief Adopt an existing nested-name-specifier (with source-range
463  /// information).
464  void Adopt(NestedNameSpecifierLoc Other);
465
466  /// \brief Retrieve the source range covered by this nested-name-specifier.
467  SourceRange getSourceRange() const LLVM_READONLY {
468    return NestedNameSpecifierLoc(Representation, Buffer).getSourceRange();
469  }
470
471  /// \brief Retrieve a nested-name-specifier with location information,
472  /// copied into the given AST context.
473  ///
474  /// \param Context The context into which this nested-name-specifier will be
475  /// copied.
476  NestedNameSpecifierLoc getWithLocInContext(ASTContext &Context) const;
477
478  /// \brief Retrieve a nested-name-specifier with location
479  /// information based on the information in this builder.
480  ///
481  /// This loc will contain references to the builder's internal data and may
482  /// be invalidated by any change to the builder.
483  NestedNameSpecifierLoc getTemporary() const {
484    return NestedNameSpecifierLoc(Representation, Buffer);
485  }
486
487  /// \brief Clear out this builder, and prepare it to build another
488  /// nested-name-specifier with source-location information.
489  void Clear() {
490    Representation = nullptr;
491    BufferSize = 0;
492  }
493
494  /// \brief Retrieve the underlying buffer.
495  ///
496  /// \returns A pair containing a pointer to the buffer of source-location
497  /// data and the size of the source-location data that resides in that
498  /// buffer.
499  std::pair<char *, unsigned> getBuffer() const {
500    return std::make_pair(Buffer, BufferSize);
501  }
502};
503
504/// Insertion operator for diagnostics.  This allows sending
505/// NestedNameSpecifiers into a diagnostic with <<.
506inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
507                                           NestedNameSpecifier *NNS) {
508  DB.AddTaggedVal(reinterpret_cast<intptr_t>(NNS),
509                  DiagnosticsEngine::ak_nestednamespec);
510  return DB;
511}
512
513}
514
515#endif
516