NestedNameSpecifier.h source code [clang_source_code/include/clang/AST/NestedNameSpecifier.h]

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
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.
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
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:
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.
236	class 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
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
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.
349	class 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
370	public:
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 <<.
515	inline 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