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"
18#include "clang/Basic/SourceLocation.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
26namespace clang {
27
28class ASTContext;
29class CXXRecordDecl;
30class IdentifierInfo;
31class LangOptions;
32class NamespaceAliasDecl;
33class NamespaceDecl;
34struct PrintingPolicy;
35class Type;
36class 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.
48class 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
74public:
75 /// The kind of specifier that completes this nested name
76 /// specifier.
77 enum SpecifierKind {
78 /// An identifier, stored as an IdentifierInfo*.
79 Identifier,
80
81 /// A namespace, stored as a NamespaceDecl*.
82 Namespace,
83
84 /// A namespace alias, stored as a NamespaceAliasDecl*.
85 NamespaceAlias,
86
87 /// A type, stored as a Type*.
88 TypeSpec,
89
90 /// A type that was preceded by the 'template' keyword,
91 /// stored as a Type*.
92 TypeSpecWithTemplate,
93
94 /// The global specifier '::'. There is no stored value.
95 Global,
96
97 /// Microsoft's '__super' specifier, stored as a CXXRecordDecl* of
98 /// the class it appeared in.
99 Super
100 };
101
102private:
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
115public:
116 NestedNameSpecifier &operator=(const NestedNameSpecifier &) = delete;
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.
174 IdentifierInfo *getAsIdentifier() const {
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.
187 NamespaceAliasDecl *getAsNamespaceAlias() const;
188
189 /// Retrieve the record declaration stored in this nested name
190 /// specifier.
191 CXXRecordDecl *getAsRecordDecl() const;
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.
236class NestedNameSpecifierLoc {
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
248public:
249 /// Construct an empty nested-name-specifier.
250 NestedNameSpecifierLoc() = default;
251
252 /// Construct a nested-name-specifier with source location information
253 /// from
254 NestedNameSpecifierLoc(NestedNameSpecifier *Qualifier, void *Data)
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.
267 NestedNameSpecifier *getNestedNameSpecifier() const {
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.
292 SourceLocation getBeginLoc() const {
293 return getSourceRange().getBegin();
294 }
295
296 /// Retrieve the location of the end of this
297 /// nested-name-specifier.
298 SourceLocation getEndLoc() const {
299 return getSourceRange().getEnd();
300 }
301
302 /// Retrieve the location of the beginning of this
303 /// component of the nested-name-specifier.
304 SourceLocation getLocalBeginLoc() const {
305 return getLocalSourceRange().getBegin();
306 }
307
308 /// Retrieve the location of the end of this component of the
309 /// nested-name-specifier.
310 SourceLocation getLocalEndLoc() const {
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.
320 NestedNameSpecifierLoc getPrefix() const {
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
335 friend bool operator==(NestedNameSpecifierLoc X,
336 NestedNameSpecifierLoc Y) {
337 return X.Qualifier == Y.Qualifier && X.Data == Y.Data;
338 }
339
340 friend bool operator!=(NestedNameSpecifierLoc X,
341 NestedNameSpecifierLoc Y) {
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.
349class NestedNameSpecifierLocBuilder {
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
370public:
371 NestedNameSpecifierLocBuilder() = default;
372 NestedNameSpecifierLocBuilder(const NestedNameSpecifierLocBuilder &Other);
373
374 NestedNameSpecifierLocBuilder &
375 operator=(const NestedNameSpecifierLocBuilder &Other);
376
377 ~NestedNameSpecifierLocBuilder() {
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,
411 SourceLocation IdentifierLoc, SourceLocation ColonColonLoc);
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.
492 NestedNameSpecifierLoc getTemporary() const {
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 <<.
515inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
516 NestedNameSpecifier *NNS) {
517 DB.AddTaggedVal(reinterpret_cast<intptr_t>(NNS),
518 DiagnosticsEngine::ak_nestednamespec);
519 return DB;
520}
521
522} // namespace clang
523
524#endif // LLVM_CLANG_AST_NESTEDNAMESPECIFIER_H
525