1	//===- DeclBase.h - Base Classes for representing declarations --*- 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 Decl and DeclContext interfaces.
10	//
11	//===----------------------------------------------------------------------===//
12
13	#ifndef LLVM_CLANG_AST_DECLBASE_H
14	#define LLVM_CLANG_AST_DECLBASE_H
15
16	#include "clang/AST/ASTDumperUtils.h"
17	#include "clang/AST/AttrIterator.h"
18	#include "clang/AST/DeclID.h"
19	#include "clang/AST/DeclarationName.h"
20	#include "clang/AST/SelectorLocationsKind.h"
21	#include "clang/Basic/IdentifierTable.h"
22	#include "clang/Basic/LLVM.h"
23	#include "clang/Basic/LangOptions.h"
24	#include "clang/Basic/SourceLocation.h"
25	#include "clang/Basic/Specifiers.h"
26	#include "llvm/ADT/ArrayRef.h"
27	#include "llvm/ADT/PointerIntPair.h"
28	#include "llvm/ADT/PointerUnion.h"
29	#include "llvm/ADT/iterator.h"
30	#include "llvm/ADT/iterator_range.h"
31	#include "llvm/Support/Casting.h"
32	#include "llvm/Support/Compiler.h"
33	#include "llvm/Support/PrettyStackTrace.h"
34	#include "llvm/Support/VersionTuple.h"
35	#include <algorithm>
36	#include <cassert>
37	#include <cstddef>
38	#include <iterator>
39	#include <string>
40	#include <type_traits>
41	#include <utility>
42
43	namespace clang {
44
45	class ASTContext;
46	class ASTMutationListener;
47	class Attr;
48	class BlockDecl;
49	class DeclContext;
50	class ExternalSourceSymbolAttr;
51	class FunctionDecl;
52	class FunctionType;
53	class IdentifierInfo;
54	enum class Linkage : unsigned char;
55	class LinkageSpecDecl;
56	class Module;
57	class NamedDecl;
58	class ObjCContainerDecl;
59	class ObjCMethodDecl;
60	struct PrintingPolicy;
61	class RecordDecl;
62	class SourceManager;
63	class Stmt;
64	class StoredDeclsMap;
65	class TemplateDecl;
66	class TemplateParameterList;
67	class TranslationUnitDecl;
68	class UsingDirectiveDecl;
69
70	/// Captures the result of checking the availability of a
71	/// declaration.
72	enum AvailabilityResult {
73	AR_Available = 0,
74	AR_NotYetIntroduced,
75	AR_Deprecated,
76	AR_Unavailable
77	};
78
79	/// Decl - This represents one declaration (or definition), e.g. a variable,
80	/// typedef, function, struct, etc.
81	///
82	/// Note: There are objects tacked on before the *beginning* of Decl
83	/// (and its subclasses) in its Decl::operator new(). Proper alignment
84	/// of all subclasses (not requiring more than the alignment of Decl) is
85	/// asserted in DeclBase.cpp.
86	class alignas(8) Decl {
87	public:
88	/// Lists the kind of concrete classes of Decl.
89	enum Kind {
90	#define DECL(DERIVED, BASE) DERIVED,
91	#define ABSTRACT_DECL(DECL)
92	#define DECL_RANGE(BASE, START, END) \
93	first##BASE = START, last##BASE = END,
94	#define LAST_DECL_RANGE(BASE, START, END) \
95	first##BASE = START, last##BASE = END
96	#include "clang/AST/DeclNodes.inc"
97	};
98
99	/// A placeholder type used to construct an empty shell of a
100	/// decl-derived type that will be filled in later (e.g., by some
101	/// deserialization method).
102	struct EmptyShell {};
103
104	/// IdentifierNamespace - The different namespaces in which
105	/// declarations may appear. According to C99 6.2.3, there are
106	/// four namespaces, labels, tags, members and ordinary
107	/// identifiers. C++ describes lookup completely differently:
108	/// certain lookups merely "ignore" certain kinds of declarations,
109	/// usually based on whether the declaration is of a type, etc.
110	///
111	/// These are meant as bitmasks, so that searches in
112	/// C++ can look into the "tag" namespace during ordinary lookup.
113	///
114	/// Decl currently provides 15 bits of IDNS bits.
115	enum IdentifierNamespace {
116	/// Labels, declared with 'x:' and referenced with 'goto x'.
117	IDNS_Label = 0x0001,
118
119	/// Tags, declared with 'struct foo;' and referenced with
120	/// 'struct foo'. All tags are also types. This is what
121	/// elaborated-type-specifiers look for in C.
122	/// This also contains names that conflict with tags in the
123	/// same scope but that are otherwise ordinary names (non-type
124	/// template parameters and indirect field declarations).
125	IDNS_Tag = 0x0002,
126
127	/// Types, declared with 'struct foo', typedefs, etc.
128	/// This is what elaborated-type-specifiers look for in C++,
129	/// but note that it's ill-formed to find a non-tag.
130	IDNS_Type = 0x0004,
131
132	/// Members, declared with object declarations within tag
133	/// definitions. In C, these can only be found by "qualified"
134	/// lookup in member expressions. In C++, they're found by
135	/// normal lookup.
136	IDNS_Member = 0x0008,
137
138	/// Namespaces, declared with 'namespace foo {}'.
139	/// Lookup for nested-name-specifiers find these.
140	IDNS_Namespace = 0x0010,
141
142	/// Ordinary names. In C, everything that's not a label, tag,
143	/// member, or function-local extern ends up here.
144	IDNS_Ordinary = 0x0020,
145
146	/// Objective C \@protocol.
147	IDNS_ObjCProtocol = 0x0040,
148
149	/// This declaration is a friend function. A friend function
150	/// declaration is always in this namespace but may also be in
151	/// IDNS_Ordinary if it was previously declared.
152	IDNS_OrdinaryFriend = 0x0080,
153
154	/// This declaration is a friend class. A friend class
155	/// declaration is always in this namespace but may also be in
156	/// IDNS_Tag|IDNS_Type if it was previously declared.
157	IDNS_TagFriend = 0x0100,
158
159	/// This declaration is a using declaration. A using declaration
160	/// *introduces* a number of other declarations into the current
161	/// scope, and those declarations use the IDNS of their targets,
162	/// but the actual using declarations go in this namespace.
163	IDNS_Using = 0x0200,
164
165	/// This declaration is a C++ operator declared in a non-class
166	/// context. All such operators are also in IDNS_Ordinary.
167	/// C++ lexical operator lookup looks for these.
168	IDNS_NonMemberOperator = 0x0400,
169
170	/// This declaration is a function-local extern declaration of a
171	/// variable or function. This may also be IDNS_Ordinary if it
172	/// has been declared outside any function. These act mostly like
173	/// invisible friend declarations, but are also visible to unqualified
174	/// lookup within the scope of the declaring function.
175	IDNS_LocalExtern = 0x0800,
176
177	/// This declaration is an OpenMP user defined reduction construction.
178	IDNS_OMPReduction = 0x1000,
179
180	/// This declaration is an OpenMP user defined mapper.
181	IDNS_OMPMapper = 0x2000,
182	};
183
184	/// ObjCDeclQualifier - 'Qualifiers' written next to the return and
185	/// parameter types in method declarations. Other than remembering
186	/// them and mangling them into the method's signature string, these
187	/// are ignored by the compiler; they are consumed by certain
188	/// remote-messaging frameworks.
189	///
190	/// in, inout, and out are mutually exclusive and apply only to
191	/// method parameters. bycopy and byref are mutually exclusive and
192	/// apply only to method parameters (?). oneway applies only to
193	/// results. All of these expect their corresponding parameter to
194	/// have a particular type. None of this is currently enforced by
195	/// clang.
196	///
197	/// This should be kept in sync with ObjCDeclSpec::ObjCDeclQualifier.
198	enum ObjCDeclQualifier {
199	OBJC_TQ_None = 0x0,
200	OBJC_TQ_In = 0x1,
201	OBJC_TQ_Inout = 0x2,
202	OBJC_TQ_Out = 0x4,
203	OBJC_TQ_Bycopy = 0x8,
204	OBJC_TQ_Byref = 0x10,
205	OBJC_TQ_Oneway = 0x20,
206
207	/// The nullability qualifier is set when the nullability of the
208	/// result or parameter was expressed via a context-sensitive
209	/// keyword.
210	OBJC_TQ_CSNullability = 0x40
211	};
212
213	/// The kind of ownership a declaration has, for visibility purposes.
214	/// This enumeration is designed such that higher values represent higher
215	/// levels of name hiding.
216	enum class ModuleOwnershipKind : unsigned char {
217	/// This declaration is not owned by a module.
218	Unowned,
219
220	/// This declaration has an owning module, but is globally visible
221	/// (typically because its owning module is visible and we know that
222	/// modules cannot later become hidden in this compilation).
223	/// After serialization and deserialization, this will be converted
224	/// to VisibleWhenImported.
225	Visible,
226
227	/// This declaration has an owning module, and is visible when that
228	/// module is imported.
229	VisibleWhenImported,
230
231	/// This declaration has an owning module, and is visible to lookups
232	/// that occurs within that module. And it is reachable in other module
233	/// when the owning module is transitively imported.
234	ReachableWhenImported,
235
236	/// This declaration has an owning module, but is only visible to
237	/// lookups that occur within that module.
238	/// The discarded declarations in global module fragment belongs
239	/// to this group too.
240	ModulePrivate
241	};
242
243	protected:
244	/// The next declaration within the same lexical
245	/// DeclContext. These pointers form the linked list that is
246	/// traversed via DeclContext's decls_begin()/decls_end().
247	///
248	/// The extra three bits are used for the ModuleOwnershipKind.
249	llvm::PointerIntPair<Decl *, 3, ModuleOwnershipKind> NextInContextAndBits;
250
251	private:
252	friend class DeclContext;
253
254	struct MultipleDC {
255	DeclContext *SemanticDC;
256	DeclContext *LexicalDC;
257	};
258
259	/// DeclCtx - Holds either a DeclContext* or a MultipleDC*.
260	/// For declarations that don't contain C++ scope specifiers, it contains
261	/// the DeclContext where the Decl was declared.
262	/// For declarations with C++ scope specifiers, it contains a MultipleDC*
263	/// with the context where it semantically belongs (SemanticDC) and the
264	/// context where it was lexically declared (LexicalDC).
265	/// e.g.:
266	///
267	/// namespace A {
268	/// void f(); // SemanticDC == LexicalDC == 'namespace A'
269	/// }
270	/// void A::f(); // SemanticDC == namespace 'A'
271	/// // LexicalDC == global namespace
272	llvm::PointerUnion<DeclContext*, MultipleDC*> DeclCtx;
273
274	bool isInSemaDC() const { return isa<DeclContext *>(DeclCtx); }
275	bool isOutOfSemaDC() const { return isa<MultipleDC *>(DeclCtx); }
276
277	MultipleDC *getMultipleDC() const { return cast<MultipleDC *>(DeclCtx); }
278
279	DeclContext *getSemanticDC() const { return cast<DeclContext *>(DeclCtx); }
280
281	/// Loc - The location of this decl.
282	SourceLocation Loc;
283
284	/// DeclKind - This indicates which class this is.
285	LLVM_PREFERRED_TYPE(Kind)
286	unsigned DeclKind : 7;
287
288	/// InvalidDecl - This indicates a semantic error occurred.
289	LLVM_PREFERRED_TYPE(bool)
290	unsigned InvalidDecl : 1;
291
292	/// HasAttrs - This indicates whether the decl has attributes or not.
293	LLVM_PREFERRED_TYPE(bool)
294	unsigned HasAttrs : 1;
295
296	/// Implicit - Whether this declaration was implicitly generated by
297	/// the implementation rather than explicitly written by the user.
298	LLVM_PREFERRED_TYPE(bool)
299	unsigned Implicit : 1;
300
301	/// Whether this declaration was "used", meaning that a definition is
302	/// required.
303	LLVM_PREFERRED_TYPE(bool)
304	unsigned Used : 1;
305
306	/// Whether this declaration was "referenced".
307	/// The difference with 'Used' is whether the reference appears in a
308	/// evaluated context or not, e.g. functions used in uninstantiated templates
309	/// are regarded as "referenced" but not "used".
310	LLVM_PREFERRED_TYPE(bool)
311	unsigned Referenced : 1;
312
313	/// Whether this declaration is a top-level declaration (function,
314	/// global variable, etc.) that is lexically inside an objc container
315	/// definition.
316	LLVM_PREFERRED_TYPE(bool)
317	unsigned TopLevelDeclInObjCContainer : 1;
318
319	/// Whether statistic collection is enabled.
320	static bool StatisticsEnabled;
321
322	protected:
323	friend class ASTDeclMerger;
324	friend class ASTDeclReader;
325	friend class ASTDeclWriter;
326	friend class ASTNodeImporter;
327	friend class ASTReader;
328	friend class CXXClassMemberWrapper;
329	friend class LinkageComputer;
330	friend class RecordDecl;
331	template<typename decl_type> friend class Redeclarable;
332
333	/// Access - Used by C++ decls for the access specifier.
334	// NOTE: VC++ treats enums as signed, avoid using the AccessSpecifier enum
335	LLVM_PREFERRED_TYPE(AccessSpecifier)
336	unsigned Access : 2;
337
338	/// Whether this declaration was loaded from an AST file.
339	LLVM_PREFERRED_TYPE(bool)
340	unsigned FromASTFile : 1;
341
342	/// IdentifierNamespace - This specifies what IDNS_* namespace this lives in.
343	LLVM_PREFERRED_TYPE(IdentifierNamespace)
344	unsigned IdentifierNamespace : 14;
345
346	/// If 0, we have not computed the linkage of this declaration.
347	LLVM_PREFERRED_TYPE(Linkage)
348	mutable unsigned CacheValidAndLinkage : 3;
349
350	/// Allocate memory for a deserialized declaration.
351	///
352	/// This routine must be used to allocate memory for any declaration that is
353	/// deserialized from a module file.
354	///
355	/// \param Size The size of the allocated object.
356	/// \param Ctx The context in which we will allocate memory.
357	/// \param ID The global ID of the deserialized declaration.
358	/// \param Extra The amount of extra space to allocate after the object.
359	void *operator new(std::size_t Size, const ASTContext &Ctx, GlobalDeclID ID,
360	std::size_t Extra = 0);
361
362	/// Allocate memory for a non-deserialized declaration.
363	void *operator new(std::size_t Size, const ASTContext &Ctx,
364	DeclContext *Parent, std::size_t Extra = 0);
365
366	private:
367	bool AccessDeclContextCheck() const;
368
369	/// Get the module ownership kind to use for a local lexical child of \p DC,
370	/// which may be either a local or (rarely) an imported declaration.
371	static ModuleOwnershipKind getModuleOwnershipKindForChildOf(DeclContext *DC) {
372	if (DC) {
373	auto *D = cast<Decl>(DC);
374	auto MOK = D->getModuleOwnershipKind();
375	if (MOK != ModuleOwnershipKind::Unowned &&
376	(!D->isFromASTFile() || D->hasLocalOwningModuleStorage()))
377	return MOK;
378	// If D is not local and we have no local module storage, then we don't
379	// need to track module ownership at all.
380	}
381	return ModuleOwnershipKind::Unowned;
382	}
383
384	public:
385	Decl() = delete;
386	Decl(const Decl&) = delete;
387	Decl(Decl &&) = delete;
388	Decl &operator=(const Decl&) = delete;
389	Decl &operator=(Decl&&) = delete;
390
391	protected:
392	Decl(Kind DK, DeclContext *DC, SourceLocation L)
393	: NextInContextAndBits(nullptr, getModuleOwnershipKindForChildOf(DC)),
394	DeclCtx(DC), Loc(L), DeclKind(DK), InvalidDecl(false), HasAttrs(false),
395	Implicit(false), Used(false), Referenced(false),
396	TopLevelDeclInObjCContainer(false), Access(AS_none), FromASTFile(0),
397	IdentifierNamespace(getIdentifierNamespaceForKind(DK)),
398	CacheValidAndLinkage(llvm::to_underlying(Linkage::Invalid)) {
399	if (StatisticsEnabled) add(k: DK);
400	}
401
402	Decl(Kind DK, EmptyShell Empty)
403	: DeclKind(DK), InvalidDecl(false), HasAttrs(false), Implicit(false),
404	Used(false), Referenced(false), TopLevelDeclInObjCContainer(false),
405	Access(AS_none), FromASTFile(0),
406	IdentifierNamespace(getIdentifierNamespaceForKind(DK)),
407	CacheValidAndLinkage(llvm::to_underlying(Linkage::Invalid)) {
408	if (StatisticsEnabled) add(k: DK);
409	}
410
411	virtual ~Decl();
412
413	/// Update a potentially out-of-date declaration.
414	void updateOutOfDate(IdentifierInfo &II) const;
415
416	Linkage getCachedLinkage() const {
417	return static_cast<Linkage>(CacheValidAndLinkage);
418	}
419
420	void setCachedLinkage(Linkage L) const {
421	CacheValidAndLinkage = llvm::to_underlying(L);
422	}
423
424	bool hasCachedLinkage() const {
425	return CacheValidAndLinkage;
426	}
427
428	public:
429	/// Source range that this declaration covers.
430	virtual SourceRange getSourceRange() const LLVM_READONLY {
431	return SourceRange(getLocation(), getLocation());
432	}
433
434	SourceLocation getBeginLoc() const LLVM_READONLY {
435	return getSourceRange().getBegin();
436	}
437
438	SourceLocation getEndLoc() const LLVM_READONLY {
439	return getSourceRange().getEnd();
440	}
441
442	SourceLocation getLocation() const { return Loc; }
443	void setLocation(SourceLocation L) { Loc = L; }
444
445	Kind getKind() const { return static_cast<Kind>(DeclKind); }
446	const char *getDeclKindName() const;
447
448	Decl *getNextDeclInContext() { return NextInContextAndBits.getPointer(); }
449	const Decl *getNextDeclInContext() const {return NextInContextAndBits.getPointer();}
450
451	DeclContext *getDeclContext() {
452	if (isInSemaDC())
453	return getSemanticDC();
454	return getMultipleDC()->SemanticDC;
455	}
456	const DeclContext *getDeclContext() const {
457	return const_cast<Decl*>(this)->getDeclContext();
458	}
459
460	/// Return the non transparent context.
461	/// See the comment of `DeclContext::isTransparentContext()` for the
462	/// definition of transparent context.
463	DeclContext *getNonTransparentDeclContext();
464	const DeclContext *getNonTransparentDeclContext() const {
465	return const_cast<Decl *>(this)->getNonTransparentDeclContext();
466	}
467
468	/// Find the innermost non-closure ancestor of this declaration,
469	/// walking up through blocks, lambdas, etc. If that ancestor is
470	/// not a code context (!isFunctionOrMethod()), returns null.
471	///
472	/// A declaration may be its own non-closure context.
473	Decl *getNonClosureContext();
474	const Decl *getNonClosureContext() const {
475	return const_cast<Decl*>(this)->getNonClosureContext();
476	}
477
478	TranslationUnitDecl *getTranslationUnitDecl();
479	const TranslationUnitDecl *getTranslationUnitDecl() const {
480	return const_cast<Decl*>(this)->getTranslationUnitDecl();
481	}
482
483	bool isInAnonymousNamespace() const;
484
485	bool isInStdNamespace() const;
486
487	// Return true if this is a FileContext Decl.
488	bool isFileContextDecl() const;
489
490	/// Whether it resembles a flexible array member. This is a static member
491	/// because we want to be able to call it with a nullptr. That allows us to
492	/// perform non-Decl specific checks based on the object's type and strict
493	/// flex array level.
494	static bool isFlexibleArrayMemberLike(
495	const ASTContext &Context, const Decl *D, QualType Ty,
496	LangOptions::StrictFlexArraysLevelKind StrictFlexArraysLevel,
497	bool IgnoreTemplateOrMacroSubstitution);
498
499	ASTContext &getASTContext() const LLVM_READONLY;
500
501	/// Helper to get the language options from the ASTContext.
502	/// Defined out of line to avoid depending on ASTContext.h.
503	const LangOptions &getLangOpts() const LLVM_READONLY;
504
505	void setAccess(AccessSpecifier AS) {
506	Access = AS;
507	assert(AccessDeclContextCheck());
508	}
509
510	AccessSpecifier getAccess() const {
511	assert(AccessDeclContextCheck());
512	return AccessSpecifier(Access);
513	}
514
515	/// Retrieve the access specifier for this declaration, even though
516	/// it may not yet have been properly set.
517	AccessSpecifier getAccessUnsafe() const {
518	return AccessSpecifier(Access);
519	}
520
521	bool hasAttrs() const { return HasAttrs; }
522
523	void setAttrs(const AttrVec& Attrs) {
524	return setAttrsImpl(Attrs, Ctx&: getASTContext());
525	}
526
527	AttrVec &getAttrs() {
528	return const_cast<AttrVec&>(const_cast<const Decl*>(this)->getAttrs());
529	}
530
531	const AttrVec &getAttrs() const;
532	void dropAttrs();
533	void addAttr(Attr *A);
534
535	using attr_iterator = AttrVec::const_iterator;
536	using attr_range = llvm::iterator_range<attr_iterator>;
537
538	attr_range attrs() const {
539	return attr_range(attr_begin(), attr_end());
540	}
541
542	attr_iterator attr_begin() const {
543	return hasAttrs() ? getAttrs().begin() : nullptr;
544	}
545	attr_iterator attr_end() const {
546	return hasAttrs() ? getAttrs().end() : nullptr;
547	}
548
549	template <typename... Ts> void dropAttrs() {
550	if (!HasAttrs) return;
551
552	AttrVec &Vec = getAttrs();
553	llvm::erase_if(Vec, [](Attr *A) { return isa<Ts...>(A); });
554
555	if (Vec.empty())
556	HasAttrs = false;
557	}
558
559	template <typename T> void dropAttr() { dropAttrs<T>(); }
560
561	template <typename T>
562	llvm::iterator_range<specific_attr_iterator<T>> specific_attrs() const {
563	return llvm::make_range(specific_attr_begin<T>(), specific_attr_end<T>());
564	}
565
566	template <typename T>
567	specific_attr_iterator<T> specific_attr_begin() const {
568	return specific_attr_iterator<T>(attr_begin());
569	}
570
571	template <typename T>
572	specific_attr_iterator<T> specific_attr_end() const {
573	return specific_attr_iterator<T>(attr_end());
574	}
575
576	template<typename T> T *getAttr() const {
577	return hasAttrs() ? getSpecificAttr<T>(getAttrs()) : nullptr;
578	}
579
580	template<typename T> bool hasAttr() const {
581	return hasAttrs() && hasSpecificAttr<T>(getAttrs());
582	}
583
584	/// getMaxAlignment - return the maximum alignment specified by attributes
585	/// on this decl, 0 if there are none.
586	unsigned getMaxAlignment() const;
587
588	/// setInvalidDecl - Indicates the Decl had a semantic error. This
589	/// allows for graceful error recovery.
590	void setInvalidDecl(bool Invalid = true);
591	bool isInvalidDecl() const { return (bool) InvalidDecl; }
592
593	/// isImplicit - Indicates whether the declaration was implicitly
594	/// generated by the implementation. If false, this declaration
595	/// was written explicitly in the source code.
596	bool isImplicit() const { return Implicit; }
597	void setImplicit(bool I = true) { Implicit = I; }
598
599	/// Whether *any* (re-)declaration of the entity was used, meaning that
600	/// a definition is required.
601	///
602	/// \param CheckUsedAttr When true, also consider the "used" attribute
603	/// (in addition to the "used" bit set by \c setUsed()) when determining
604	/// whether the function is used.
605	bool isUsed(bool CheckUsedAttr = true) const;
606
607	/// Set whether the declaration is used, in the sense of odr-use.
608	///
609	/// This should only be used immediately after creating a declaration.
610	/// It intentionally doesn't notify any listeners.
611	void setIsUsed() { getCanonicalDecl()->Used = true; }
612
613	/// Mark the declaration used, in the sense of odr-use.
614	///
615	/// This notifies any mutation listeners in addition to setting a bit
616	/// indicating the declaration is used.
617	void markUsed(ASTContext &C);
618
619	/// Whether any declaration of this entity was referenced.
620	bool isReferenced() const;
621
622	/// Whether this declaration was referenced. This should not be relied
623	/// upon for anything other than debugging.
624	bool isThisDeclarationReferenced() const { return Referenced; }
625
626	void setReferenced(bool R = true) { Referenced = R; }
627
628	/// Whether this declaration is a top-level declaration (function,
629	/// global variable, etc.) that is lexically inside an objc container
630	/// definition.
631	bool isTopLevelDeclInObjCContainer() const {
632	return TopLevelDeclInObjCContainer;
633	}
634
635	void setTopLevelDeclInObjCContainer(bool V = true) {
636	TopLevelDeclInObjCContainer = V;
637	}
638
639	/// Looks on this and related declarations for an applicable
640	/// external source symbol attribute.
641	ExternalSourceSymbolAttr *getExternalSourceSymbolAttr() const;
642
643	/// Whether this declaration was marked as being private to the
644	/// module in which it was defined.
645	bool isModulePrivate() const {
646	return getModuleOwnershipKind() == ModuleOwnershipKind::ModulePrivate;
647	}
648
649	/// Whether this declaration was exported in a lexical context.
650	/// e.g.:
651	///
652	/// export namespace A {
653	/// void f1(); // isInExportDeclContext() == true
654	/// }
655	/// void A::f1(); // isInExportDeclContext() == false
656	///
657	/// namespace B {
658	/// void f2(); // isInExportDeclContext() == false
659	/// }
660	/// export void B::f2(); // isInExportDeclContext() == true
661	bool isInExportDeclContext() const;
662
663	bool isInvisibleOutsideTheOwningModule() const {
664	return getModuleOwnershipKind() > ModuleOwnershipKind::VisibleWhenImported;
665	}
666
667	/// Whether this declaration comes from another module unit.
668	bool isInAnotherModuleUnit() const;
669
670	/// Whether this declaration comes from the same module unit being compiled.
671	bool isInCurrentModuleUnit() const;
672
673	/// Whether the definition of the declaration should be emitted in external
674	/// sources.
675	bool shouldEmitInExternalSource() const;
676
677	/// Whether this declaration comes from explicit global module.
678	bool isFromExplicitGlobalModule() const;
679
680	/// Whether this declaration comes from global module.
681	bool isFromGlobalModule() const;
682
683	/// Whether this declaration comes from a named module.
684	bool isInNamedModule() const;
685
686	/// Whether this declaration comes from a header unit.
687	bool isFromHeaderUnit() const;
688
689	/// Return true if this declaration has an attribute which acts as
690	/// definition of the entity, such as 'alias' or 'ifunc'.
691	bool hasDefiningAttr() const;
692
693	/// Return this declaration's defining attribute if it has one.
694	const Attr *getDefiningAttr() const;
695
696	protected:
697	/// Specify that this declaration was marked as being private
698	/// to the module in which it was defined.
699	void setModulePrivate() {
700	// The module-private specifier has no effect on unowned declarations.
701	// FIXME: We should track this in some way for source fidelity.
702	if (getModuleOwnershipKind() == ModuleOwnershipKind::Unowned)
703	return;
704	setModuleOwnershipKind(ModuleOwnershipKind::ModulePrivate);
705	}
706
707	public:
708	/// Set the FromASTFile flag. This indicates that this declaration
709	/// was deserialized and not parsed from source code and enables
710	/// features such as module ownership information.
711	void setFromASTFile() {
712	FromASTFile = true;
713	}
714
715	/// Set the owning module ID. This may only be called for
716	/// deserialized Decls.
717	void setOwningModuleID(unsigned ID);
718
719	public:
720	/// Determine the availability of the given declaration.
721	///
722	/// This routine will determine the most restrictive availability of
723	/// the given declaration (e.g., preferring 'unavailable' to
724	/// 'deprecated').
725	///
726	/// \param Message If non-NULL and the result is not \c
727	/// AR_Available, will be set to a (possibly empty) message
728	/// describing why the declaration has not been introduced, is
729	/// deprecated, or is unavailable.
730	///
731	/// \param EnclosingVersion The version to compare with. If empty, assume the
732	/// deployment target version.
733	///
734	/// \param RealizedPlatform If non-NULL and the availability result is found
735	/// in an available attribute it will set to the platform which is written in
736	/// the available attribute.
737	AvailabilityResult
738	getAvailability(std::string *Message = nullptr,
739	VersionTuple EnclosingVersion = VersionTuple(),
740	StringRef *RealizedPlatform = nullptr) const;
741
742	/// Retrieve the version of the target platform in which this
743	/// declaration was introduced.
744	///
745	/// \returns An empty version tuple if this declaration has no 'introduced'
746	/// availability attributes, or the version tuple that's specified in the
747	/// attribute otherwise.
748	VersionTuple getVersionIntroduced() const;
749
750	/// Determine whether this declaration is marked 'deprecated'.
751	///
752	/// \param Message If non-NULL and the declaration is deprecated,
753	/// this will be set to the message describing why the declaration
754	/// was deprecated (which may be empty).
755	bool isDeprecated(std::string *Message = nullptr) const {
756	return getAvailability(Message) == AR_Deprecated;
757	}
758
759	/// Determine whether this declaration is marked 'unavailable'.
760	///
761	/// \param Message If non-NULL and the declaration is unavailable,
762	/// this will be set to the message describing why the declaration
763	/// was made unavailable (which may be empty).
764	bool isUnavailable(std::string *Message = nullptr) const {
765	return getAvailability(Message) == AR_Unavailable;
766	}
767
768	/// Determine whether this is a weak-imported symbol.
769	///
770	/// Weak-imported symbols are typically marked with the
771	/// 'weak_import' attribute, but may also be marked with an
772	/// 'availability' attribute where we're targing a platform prior to
773	/// the introduction of this feature.
774	bool isWeakImported() const;
775
776	/// Determines whether this symbol can be weak-imported,
777	/// e.g., whether it would be well-formed to add the weak_import
778	/// attribute.
779	///
780	/// \param IsDefinition Set to \c true to indicate that this
781	/// declaration cannot be weak-imported because it has a definition.
782	bool canBeWeakImported(bool &IsDefinition) const;
783
784	/// Determine whether this declaration came from an AST file (such as
785	/// a precompiled header or module) rather than having been parsed.
786	bool isFromASTFile() const { return FromASTFile; }
787
788	/// Retrieve the global declaration ID associated with this
789	/// declaration, which specifies where this Decl was loaded from.
790	GlobalDeclID getGlobalID() const;
791
792	/// Retrieve the global ID of the module that owns this particular
793	/// declaration.
794	unsigned getOwningModuleID() const;
795
796	private:
797	Module *getOwningModuleSlow() const;
798
799	protected:
800	bool hasLocalOwningModuleStorage() const;
801
802	public:
803	/// Get the imported owning module, if this decl is from an imported
804	/// (non-local) module.
805	Module *getImportedOwningModule() const {
806	if (!isFromASTFile() || !hasOwningModule())
807	return nullptr;
808
809	return getOwningModuleSlow();
810	}
811
812	/// Get the local owning module, if known. Returns nullptr if owner is
813	/// not yet known or declaration is not from a module.
814	Module *getLocalOwningModule() const {
815	if (isFromASTFile() || !hasOwningModule())
816	return nullptr;
817
818	assert(hasLocalOwningModuleStorage() &&
819	"owned local decl but no local module storage");
820	return reinterpret_cast<Module *const *>(this)[-1];
821	}
822	void setLocalOwningModule(Module *M) {
823	assert(!isFromASTFile() && hasOwningModule() &&
824	hasLocalOwningModuleStorage() &&
825	"should not have a cached owning module");
826	reinterpret_cast<Module **>(this)[-1] = M;
827	}
828
829	/// Is this declaration owned by some module?
830	bool hasOwningModule() const {
831	return getModuleOwnershipKind() != ModuleOwnershipKind::Unowned;
832	}
833
834	/// Get the module that owns this declaration (for visibility purposes).
835	Module *getOwningModule() const {
836	return isFromASTFile() ? getImportedOwningModule() : getLocalOwningModule();
837	}
838
839	/// Get the top level owning named module that owns this declaration if any.
840	/// \returns nullptr if the declaration is not owned by a named module.
841	Module *getTopLevelOwningNamedModule() const;
842
843	/// Get the module that owns this declaration for linkage purposes.
844	/// There only ever is such a standard C++ module.
845	Module *getOwningModuleForLinkage() const;
846
847	/// Determine whether this declaration is definitely visible to name lookup,
848	/// independent of whether the owning module is visible.
849	/// Note: The declaration may be visible even if this returns \c false if the
850	/// owning module is visible within the query context. This is a low-level
851	/// helper function; most code should be calling Sema::isVisible() instead.
852	bool isUnconditionallyVisible() const {
853	return (int)getModuleOwnershipKind() <= (int)ModuleOwnershipKind::Visible;
854	}
855
856	bool isReachable() const {
857	return (int)getModuleOwnershipKind() <=
858	(int)ModuleOwnershipKind::ReachableWhenImported;
859	}
860
861	/// Set that this declaration is globally visible, even if it came from a
862	/// module that is not visible.
863	void setVisibleDespiteOwningModule() {
864	if (!isUnconditionallyVisible())
865	setModuleOwnershipKind(ModuleOwnershipKind::Visible);
866	}
867
868	/// Get the kind of module ownership for this declaration.
869	ModuleOwnershipKind getModuleOwnershipKind() const {
870	return NextInContextAndBits.getInt();
871	}
872
873	/// Set whether this declaration is hidden from name lookup.
874	void setModuleOwnershipKind(ModuleOwnershipKind MOK) {
875	assert(!(getModuleOwnershipKind() == ModuleOwnershipKind::Unowned &&
876	MOK != ModuleOwnershipKind::Unowned && !isFromASTFile() &&
877	!hasLocalOwningModuleStorage()) &&
878	"no storage available for owning module for this declaration");
879	NextInContextAndBits.setInt(MOK);
880	}
881
882	unsigned getIdentifierNamespace() const {
883	return IdentifierNamespace;
884	}
885
886	bool isInIdentifierNamespace(unsigned NS) const {
887	return getIdentifierNamespace() & NS;
888	}
889
890	static unsigned getIdentifierNamespaceForKind(Kind DK);
891
892	bool hasTagIdentifierNamespace() const {
893	return isTagIdentifierNamespace(NS: getIdentifierNamespace());
894	}
895
896	static bool isTagIdentifierNamespace(unsigned NS) {
897	// TagDecls have Tag and Type set and may also have TagFriend.
898	return (NS & ~IDNS_TagFriend) == (IDNS_Tag | IDNS_Type);
899	}
900
901	/// getLexicalDeclContext - The declaration context where this Decl was
902	/// lexically declared (LexicalDC). May be different from
903	/// getDeclContext() (SemanticDC).
904	/// e.g.:
905	///
906	/// namespace A {
907	/// void f(); // SemanticDC == LexicalDC == 'namespace A'
908	/// }
909	/// void A::f(); // SemanticDC == namespace 'A'
910	/// // LexicalDC == global namespace
911	DeclContext *getLexicalDeclContext() {
912	if (isInSemaDC())
913	return getSemanticDC();
914	return getMultipleDC()->LexicalDC;
915	}
916	const DeclContext *getLexicalDeclContext() const {
917	return const_cast<Decl*>(this)->getLexicalDeclContext();
918	}
919
920	/// Determine whether this declaration is declared out of line (outside its
921	/// semantic context).
922	virtual bool isOutOfLine() const;
923
924	/// setDeclContext - Set both the semantic and lexical DeclContext
925	/// to DC.
926	void setDeclContext(DeclContext *DC);
927
928	void setLexicalDeclContext(DeclContext *DC);
929
930	/// Determine whether this declaration is a templated entity (whether it is
931	// within the scope of a template parameter).
932	bool isTemplated() const;
933
934	/// Determine the number of levels of template parameter surrounding this
935	/// declaration.
936	unsigned getTemplateDepth() const;
937
938	/// isDefinedOutsideFunctionOrMethod - This predicate returns true if this
939	/// scoped decl is defined outside the current function or method. This is
940	/// roughly global variables and functions, but also handles enums (which
941	/// could be defined inside or outside a function etc).
942	bool isDefinedOutsideFunctionOrMethod() const {
943	return getParentFunctionOrMethod() == nullptr;
944	}
945
946	/// Determine whether a substitution into this declaration would occur as
947	/// part of a substitution into a dependent local scope. Such a substitution
948	/// transitively substitutes into all constructs nested within this
949	/// declaration.
950	///
951	/// This recognizes non-defining declarations as well as members of local
952	/// classes and lambdas:
953	/// \code
954	/// template<typename T> void foo() { void bar(); }
955	/// template<typename T> void foo2() { class ABC { void bar(); }; }
956	/// template<typename T> inline int x = [](){ return 0; }();
957	/// \endcode
958	bool isInLocalScopeForInstantiation() const;
959
960	/// If this decl is defined inside a function/method/block it returns
961	/// the corresponding DeclContext, otherwise it returns null.
962	const DeclContext *
963	getParentFunctionOrMethod(bool LexicalParent = false) const;
964	DeclContext *getParentFunctionOrMethod(bool LexicalParent = false) {
965	return const_cast<DeclContext *>(
966	const_cast<const Decl *>(this)->getParentFunctionOrMethod(
967	LexicalParent));
968	}
969
970	/// Retrieves the "canonical" declaration of the given declaration.
971	virtual Decl *getCanonicalDecl() { return this; }
972	const Decl *getCanonicalDecl() const {
973	return const_cast<Decl*>(this)->getCanonicalDecl();
974	}
975
976	/// Whether this particular Decl is a canonical one.
977	bool isCanonicalDecl() const { return getCanonicalDecl() == this; }
978
979	protected:
980	/// Returns the next redeclaration or itself if this is the only decl.
981	///
982	/// Decl subclasses that can be redeclared should override this method so that
983	/// Decl::redecl_iterator can iterate over them.
984	virtual Decl *getNextRedeclarationImpl() { return this; }
985
986	/// Implementation of getPreviousDecl(), to be overridden by any
987	/// subclass that has a redeclaration chain.
988	virtual Decl *getPreviousDeclImpl() { return nullptr; }
989
990	/// Implementation of getMostRecentDecl(), to be overridden by any
991	/// subclass that has a redeclaration chain.
992	virtual Decl *getMostRecentDeclImpl() { return this; }
993
994	public:
995	/// Iterates through all the redeclarations of the same decl.
996	class redecl_iterator {
997	/// Current - The current declaration.
998	Decl *Current = nullptr;
999	Decl *Starter;
1000
1001	public:
1002	using value_type = Decl *;
1003	using reference = const value_type &;
1004	using pointer = const value_type *;
1005	using iterator_category = std::forward_iterator_tag;
1006	using difference_type = std::ptrdiff_t;
1007
1008	redecl_iterator() = default;
1009	explicit redecl_iterator(Decl *C) : Current(C), Starter(C) {}
1010
1011	reference operator*() const { return Current; }
1012	value_type operator->() const { return Current; }
1013
1014	redecl_iterator& operator++() {
1015	assert(Current && "Advancing while iterator has reached end");
1016	// Get either previous decl or latest decl.
1017	Decl *Next = Current->getNextRedeclarationImpl();
1018	assert(Next && "Should return next redeclaration or itself, never null!");
1019	Current = (Next != Starter) ? Next : nullptr;
1020	return *this;
1021	}
1022
1023	redecl_iterator operator++(int) {
1024	redecl_iterator tmp(*this);
1025	++(*this);
1026	return tmp;
1027	}
1028
1029	friend bool operator==(redecl_iterator x, redecl_iterator y) {
1030	return x.Current == y.Current;
1031	}
1032
1033	friend bool operator!=(redecl_iterator x, redecl_iterator y) {
1034	return x.Current != y.Current;
1035	}
1036	};
1037
1038	using redecl_range = llvm::iterator_range<redecl_iterator>;
1039
1040	/// Returns an iterator range for all the redeclarations of the same
1041	/// decl. It will iterate at least once (when this decl is the only one).
1042	redecl_range redecls() const {
1043	return redecl_range(redecls_begin(), redecls_end());
1044	}
1045
1046	redecl_iterator redecls_begin() const {
1047	return redecl_iterator(const_cast<Decl *>(this));
1048	}
1049
1050	redecl_iterator redecls_end() const { return redecl_iterator(); }
1051
1052	/// Retrieve the previous declaration that declares the same entity
1053	/// as this declaration, or NULL if there is no previous declaration.
1054	Decl *getPreviousDecl() { return getPreviousDeclImpl(); }
1055
1056	/// Retrieve the previous declaration that declares the same entity
1057	/// as this declaration, or NULL if there is no previous declaration.
1058	const Decl *getPreviousDecl() const {
1059	return const_cast<Decl *>(this)->getPreviousDeclImpl();
1060	}
1061
1062	/// True if this is the first declaration in its redeclaration chain.
1063	bool isFirstDecl() const {
1064	return getPreviousDecl() == nullptr;
1065	}
1066
1067	/// Retrieve the most recent declaration that declares the same entity
1068	/// as this declaration (which may be this declaration).
1069	Decl *getMostRecentDecl() { return getMostRecentDeclImpl(); }
1070
1071	/// Retrieve the most recent declaration that declares the same entity
1072	/// as this declaration (which may be this declaration).
1073	const Decl *getMostRecentDecl() const {
1074	return const_cast<Decl *>(this)->getMostRecentDeclImpl();
1075	}
1076
1077	/// getBody - If this Decl represents a declaration for a body of code,
1078	/// such as a function or method definition, this method returns the
1079	/// top-level Stmt* of that body. Otherwise this method returns null.
1080	virtual Stmt* getBody() const { return nullptr; }
1081
1082	/// Returns true if this \c Decl represents a declaration for a body of
1083	/// code, such as a function or method definition.
1084	/// Note that \c hasBody can also return true if any redeclaration of this
1085	/// \c Decl represents a declaration for a body of code.
1086	virtual bool hasBody() const { return getBody() != nullptr; }
1087
1088	/// getBodyRBrace - Gets the right brace of the body, if a body exists.
1089	/// This works whether the body is a CompoundStmt or a CXXTryStmt.
1090	SourceLocation getBodyRBrace() const;
1091
1092	// global temp stats (until we have a per-module visitor)
1093	static void add(Kind k);
1094	static void EnableStatistics();
1095	static void PrintStats();
1096
1097	/// isTemplateParameter - Determines whether this declaration is a
1098	/// template parameter.
1099	bool isTemplateParameter() const;
1100
1101	/// isTemplateParameter - Determines whether this declaration is a
1102	/// template parameter pack.
1103	bool isTemplateParameterPack() const;
1104
1105	/// Whether this declaration is a parameter pack.
1106	bool isParameterPack() const;
1107
1108	/// returns true if this declaration is a template
1109	bool isTemplateDecl() const;
1110
1111	/// Whether this declaration is a function or function template.
1112	bool isFunctionOrFunctionTemplate() const {
1113	return (DeclKind >= Decl::firstFunction &&
1114	DeclKind <= Decl::lastFunction) ||
1115	DeclKind == FunctionTemplate;
1116	}
1117
1118	/// If this is a declaration that describes some template, this
1119	/// method returns that template declaration.
1120	///
1121	/// Note that this returns nullptr for partial specializations, because they
1122	/// are not modeled as TemplateDecls. Use getDescribedTemplateParams to handle
1123	/// those cases.
1124	TemplateDecl *getDescribedTemplate() const;
1125
1126	/// If this is a declaration that describes some template or partial
1127	/// specialization, this returns the corresponding template parameter list.
1128	const TemplateParameterList *getDescribedTemplateParams() const;
1129
1130	/// Returns the function itself, or the templated function if this is a
1131	/// function template.
1132	FunctionDecl *getAsFunction() LLVM_READONLY;
1133
1134	const FunctionDecl *getAsFunction() const {
1135	return const_cast<Decl *>(this)->getAsFunction();
1136	}
1137
1138	/// Changes the namespace of this declaration to reflect that it's
1139	/// a function-local extern declaration.
1140	///
1141	/// These declarations appear in the lexical context of the extern
1142	/// declaration, but in the semantic context of the enclosing namespace
1143	/// scope.
1144	void setLocalExternDecl() {
1145	Decl *Prev = getPreviousDecl();
1146	IdentifierNamespace &= ~IDNS_Ordinary;
1147
1148	// It's OK for the declaration to still have the "invisible friend" flag or
1149	// the "conflicts with tag declarations in this scope" flag for the outer
1150	// scope.
1151	assert((IdentifierNamespace & ~(IDNS_OrdinaryFriend | IDNS_Tag)) == 0 &&
1152	"namespace is not ordinary");
1153
1154	IdentifierNamespace |= IDNS_LocalExtern;
1155	if (Prev && Prev->getIdentifierNamespace() & IDNS_Ordinary)
1156	IdentifierNamespace |= IDNS_Ordinary;
1157	}
1158
1159	/// Determine whether this is a block-scope declaration with linkage.
1160	/// This will either be a local variable declaration declared 'extern', or a
1161	/// local function declaration.
1162	bool isLocalExternDecl() const {
1163	return IdentifierNamespace & IDNS_LocalExtern;
1164	}
1165
1166	/// Changes the namespace of this declaration to reflect that it's
1167	/// the object of a friend declaration.
1168	///
1169	/// These declarations appear in the lexical context of the friending
1170	/// class, but in the semantic context of the actual entity. This property
1171	/// applies only to a specific decl object; other redeclarations of the
1172	/// same entity may not (and probably don't) share this property.
1173	void setObjectOfFriendDecl(bool PerformFriendInjection = false) {
1174	unsigned OldNS = IdentifierNamespace;
1175	assert((OldNS & (IDNS_Tag | IDNS_Ordinary |
1176	IDNS_TagFriend | IDNS_OrdinaryFriend |
1177	IDNS_LocalExtern | IDNS_NonMemberOperator)) &&
1178	"namespace includes neither ordinary nor tag");
1179	assert(!(OldNS & ~(IDNS_Tag | IDNS_Ordinary | IDNS_Type |
1180	IDNS_TagFriend | IDNS_OrdinaryFriend |
1181	IDNS_LocalExtern | IDNS_NonMemberOperator)) &&
1182	"namespace includes other than ordinary or tag");
1183
1184	Decl *Prev = getPreviousDecl();
1185	IdentifierNamespace &= ~(IDNS_Ordinary | IDNS_Tag | IDNS_Type);
1186
1187	if (OldNS & (IDNS_Tag | IDNS_TagFriend)) {
1188	IdentifierNamespace |= IDNS_TagFriend;
1189	if (PerformFriendInjection ||
1190	(Prev && Prev->getIdentifierNamespace() & IDNS_Tag))
1191	IdentifierNamespace |= IDNS_Tag | IDNS_Type;
1192	}
1193
1194	if (OldNS & (IDNS_Ordinary | IDNS_OrdinaryFriend |
1195	IDNS_LocalExtern | IDNS_NonMemberOperator)) {
1196	IdentifierNamespace |= IDNS_OrdinaryFriend;
1197	if (PerformFriendInjection ||
1198	(Prev && Prev->getIdentifierNamespace() & IDNS_Ordinary))
1199	IdentifierNamespace |= IDNS_Ordinary;
1200	}
1201	}
1202
1203	/// Clears the namespace of this declaration.
1204	///
1205	/// This is useful if we want this declaration to be available for
1206	/// redeclaration lookup but otherwise hidden for ordinary name lookups.
1207	void clearIdentifierNamespace() { IdentifierNamespace = 0; }
1208
1209	enum FriendObjectKind {
1210	FOK_None, ///< Not a friend object.
1211	FOK_Declared, ///< A friend of a previously-declared entity.
1212	FOK_Undeclared ///< A friend of a previously-undeclared entity.
1213	};
1214
1215	/// Determines whether this declaration is the object of a
1216	/// friend declaration and, if so, what kind.
1217	///
1218	/// There is currently no direct way to find the associated FriendDecl.
1219	FriendObjectKind getFriendObjectKind() const {
1220	unsigned mask =
1221	(IdentifierNamespace & (IDNS_TagFriend | IDNS_OrdinaryFriend));
1222	if (!mask) return FOK_None;
1223	return (IdentifierNamespace & (IDNS_Tag | IDNS_Ordinary) ? FOK_Declared
1224	: FOK_Undeclared);
1225	}
1226
1227	/// Specifies that this declaration is a C++ overloaded non-member.
1228	void setNonMemberOperator() {
1229	assert(getKind() == Function || getKind() == FunctionTemplate);
1230	assert((IdentifierNamespace & IDNS_Ordinary) &&
1231	"visible non-member operators should be in ordinary namespace");
1232	IdentifierNamespace |= IDNS_NonMemberOperator;
1233	}
1234
1235	static bool classofKind(Kind K) { return true; }
1236	static DeclContext *castToDeclContext(const Decl *);
1237	static Decl *castFromDeclContext(const DeclContext *);
1238
1239	void print(raw_ostream &Out, unsigned Indentation = 0,
1240	bool PrintInstantiation = false) const;
1241	void print(raw_ostream &Out, const PrintingPolicy &Policy,
1242	unsigned Indentation = 0, bool PrintInstantiation = false) const;
1243	static void printGroup(Decl** Begin, unsigned NumDecls,
1244	raw_ostream &Out, const PrintingPolicy &Policy,
1245	unsigned Indentation = 0);
1246
1247	// Debuggers don't usually respect default arguments.
1248	void dump() const;
1249
1250	// Same as dump(), but forces color printing.
1251	void dumpColor() const;
1252
1253	void dump(raw_ostream &Out, bool Deserialize = false,
1254	ASTDumpOutputFormat OutputFormat = ADOF_Default) const;
1255
1256	/// \return Unique reproducible object identifier
1257	int64_t getID() const;
1258
1259	/// Looks through the Decl's underlying type to extract a FunctionType
1260	/// when possible. This includes direct FunctionDecls, along with various
1261	/// function types and typedefs. This includes function pointers/references,
1262	/// member function pointers, and optionally if \p BlocksToo is set
1263	/// Objective-C block pointers. Returns nullptr if the type underlying the
1264	/// Decl does not have a FunctionType.
1265	const FunctionType *getFunctionType(bool BlocksToo = true) const;
1266
1267	// Looks through the Decl's underlying type to determine if it's a
1268	// function pointer type.
1269	bool isFunctionPointerType() const;
1270
1271	private:
1272	void setAttrsImpl(const AttrVec& Attrs, ASTContext &Ctx);
1273	void setDeclContextsImpl(DeclContext *SemaDC, DeclContext *LexicalDC,
1274	ASTContext &Ctx);
1275
1276	protected:
1277	ASTMutationListener *getASTMutationListener() const;
1278	};
1279
1280	/// Determine whether two declarations declare the same entity.
1281	inline bool declaresSameEntity(const Decl *D1, const Decl *D2) {
1282	if (!D1 || !D2)
1283	return false;
1284
1285	if (D1 == D2)
1286	return true;
1287
1288	return D1->getCanonicalDecl() == D2->getCanonicalDecl();
1289	}
1290
1291	/// PrettyStackTraceDecl - If a crash occurs, indicate that it happened when
1292	/// doing something to a specific decl.
1293	class PrettyStackTraceDecl : public llvm::PrettyStackTraceEntry {
1294	const Decl *TheDecl;
1295	SourceLocation Loc;
1296	SourceManager &SM;
1297	const char *Message;
1298
1299	public:
1300	PrettyStackTraceDecl(const Decl *theDecl, SourceLocation L,
1301	SourceManager &sm, const char *Msg)
1302	: TheDecl(theDecl), Loc(L), SM(sm), Message(Msg) {}
1303
1304	void print(raw_ostream &OS) const override;
1305	};
1306	} // namespace clang
1307
1308	// Required to determine the layout of the PointerUnion<NamedDecl*> before
1309	// seeing the NamedDecl definition being first used in DeclListNode::operator*.
1310	namespace llvm {
1311	template <> struct PointerLikeTypeTraits<::clang::NamedDecl *> {
1312	static inline void *getAsVoidPointer(::clang::NamedDecl *P) { return P; }
1313	static inline ::clang::NamedDecl *getFromVoidPointer(void *P) {
1314	return static_cast<::clang::NamedDecl *>(P);
1315	}
1316	static constexpr int NumLowBitsAvailable = 3;
1317	};
1318	}
1319
1320	namespace clang {
1321	/// A list storing NamedDecls in the lookup tables.
1322	class DeclListNode {
1323	friend class ASTContext; // allocate, deallocate nodes.
1324	friend class StoredDeclsList;
1325	public:
1326	using Decls = llvm::PointerUnion<NamedDecl*, DeclListNode*>;
1327	class iterator {
1328	friend class DeclContextLookupResult;
1329	friend class StoredDeclsList;
1330
1331	Decls Ptr;
1332	iterator(Decls Node) : Ptr(Node) { }
1333	public:
1334	using difference_type = ptrdiff_t;
1335	using value_type = NamedDecl*;
1336	using pointer = void;
1337	using reference = value_type;
1338	using iterator_category = std::forward_iterator_tag;
1339
1340	iterator() = default;
1341
1342	reference operator*() const {
1343	assert(Ptr && "dereferencing end() iterator");
1344	if (DeclListNode *CurNode = dyn_cast<DeclListNode *>(Val: Ptr))
1345	return CurNode->D;
1346	return cast<NamedDecl *>(Val: Ptr);
1347	}
1348	void operator->() const { } // Unsupported.
1349	bool operator==(const iterator &X) const { return Ptr == X.Ptr; }
1350	bool operator!=(const iterator &X) const { return Ptr != X.Ptr; }
1351	inline iterator &operator++() { // ++It
1352	assert(!Ptr.isNull() && "Advancing empty iterator");
1353
1354	if (DeclListNode *CurNode = dyn_cast<DeclListNode *>(Val&: Ptr))
1355	Ptr = CurNode->Rest;
1356	else
1357	Ptr = nullptr;
1358	return *this;
1359	}
1360	iterator operator++(int) { // It++
1361	iterator temp = *this;
1362	++(*this);
1363	return temp;
1364	}
1365	// Enables the pattern for (iterator I =..., E = I.end(); I != E; ++I)
1366	iterator end() { return iterator(); }
1367	};
1368	private:
1369	NamedDecl *D = nullptr;
1370	Decls Rest = nullptr;
1371	DeclListNode(NamedDecl *ND) : D(ND) {}
1372	};
1373
1374	/// The results of name lookup within a DeclContext.
1375	class DeclContextLookupResult {
1376	using Decls = DeclListNode::Decls;
1377
1378	/// When in collection form, this is what the Data pointer points to.
1379	Decls Result;
1380
1381	public:
1382	DeclContextLookupResult() = default;
1383	DeclContextLookupResult(Decls Result) : Result(Result) {}
1384
1385	using iterator = DeclListNode::iterator;
1386	using const_iterator = iterator;
1387	using reference = iterator::reference;
1388
1389	iterator begin() { return iterator(Result); }
1390	iterator end() { return iterator(); }
1391	const_iterator begin() const {
1392	return const_cast<DeclContextLookupResult*>(this)->begin();
1393	}
1394	const_iterator end() const { return iterator(); }
1395
1396	bool empty() const { return Result.isNull(); }
1397	bool isSingleResult() const { return isa_and_present<NamedDecl *>(Val: Result); }
1398	reference front() const { return *begin(); }
1399
1400	// Find the first declaration of the given type in the list. Note that this
1401	// is not in general the earliest-declared declaration, and should only be
1402	// used when it's not possible for there to be more than one match or where
1403	// it doesn't matter which one is found.
1404	template<class T> T *find_first() const {
1405	for (auto *D : *this)
1406	if (T *Decl = dyn_cast<T>(D))
1407	return Decl;
1408
1409	return nullptr;
1410	}
1411	};
1412
1413	/// Only used by CXXDeductionGuideDecl.
1414	enum class DeductionCandidate : unsigned char {
1415	Normal,
1416	Copy,
1417	Aggregate,
1418	};
1419
1420	enum class RecordArgPassingKind;
1421	enum class OMPDeclareReductionInitKind;
1422	enum class ObjCImplementationControl;
1423	enum class LinkageSpecLanguageIDs;
1424
1425	/// DeclContext - This is used only as base class of specific decl types that
1426	/// can act as declaration contexts. These decls are (only the top classes
1427	/// that directly derive from DeclContext are mentioned, not their subclasses):
1428	///
1429	/// TranslationUnitDecl
1430	/// ExternCContext
1431	/// NamespaceDecl
1432	/// TagDecl
1433	/// OMPDeclareReductionDecl
1434	/// OMPDeclareMapperDecl
1435	/// FunctionDecl
1436	/// ObjCMethodDecl
1437	/// ObjCContainerDecl
1438	/// LinkageSpecDecl
1439	/// ExportDecl
1440	/// BlockDecl
1441	/// CapturedDecl
1442	class DeclContext {
1443	/// For makeDeclVisibleInContextImpl
1444	friend class ASTDeclReader;
1445	/// For checking the new bits in the Serialization part.
1446	friend class ASTDeclWriter;
1447	/// For reconcileExternalVisibleStorage, CreateStoredDeclsMap,
1448	/// hasNeedToReconcileExternalVisibleStorage
1449	friend class ExternalASTSource;
1450	/// For CreateStoredDeclsMap
1451	friend class DependentDiagnostic;
1452	/// For hasNeedToReconcileExternalVisibleStorage,
1453	/// hasLazyLocalLexicalLookups, hasLazyExternalLexicalLookups
1454	friend class ASTWriter;
1455
1456	protected:
1457	enum { NumOdrHashBits = 25 };
1458
1459	// We use uint64_t in the bit-fields below since some bit-fields
1460	// cross the unsigned boundary and this breaks the packing.
1461
1462	/// Stores the bits used by DeclContext.
1463	/// If modified NumDeclContextBit, the ctor of DeclContext and the accessor
1464	/// methods in DeclContext should be updated appropriately.
1465	class DeclContextBitfields {
1466	friend class DeclContext;
1467	/// DeclKind - This indicates which class this is.
1468	LLVM_PREFERRED_TYPE(Decl::Kind)
1469	uint64_t DeclKind : 7;
1470
1471	/// Whether this declaration context also has some external
1472	/// storage that contains additional declarations that are lexically
1473	/// part of this context.
1474	LLVM_PREFERRED_TYPE(bool)
1475	mutable uint64_t ExternalLexicalStorage : 1;
1476
1477	/// Whether this declaration context also has some external
1478	/// storage that contains additional declarations that are visible
1479	/// in this context.
1480	LLVM_PREFERRED_TYPE(bool)
1481	mutable uint64_t ExternalVisibleStorage : 1;
1482
1483	/// Whether this declaration context has had externally visible
1484	/// storage added since the last lookup. In this case, \c LookupPtr's
1485	/// invariant may not hold and needs to be fixed before we perform
1486	/// another lookup.
1487	LLVM_PREFERRED_TYPE(bool)
1488	mutable uint64_t NeedToReconcileExternalVisibleStorage : 1;
1489
1490	/// If \c true, this context may have local lexical declarations
1491	/// that are missing from the lookup table.
1492	LLVM_PREFERRED_TYPE(bool)
1493	mutable uint64_t HasLazyLocalLexicalLookups : 1;
1494
1495	/// If \c true, the external source may have lexical declarations
1496	/// that are missing from the lookup table.
1497	LLVM_PREFERRED_TYPE(bool)
1498	mutable uint64_t HasLazyExternalLexicalLookups : 1;
1499
1500	/// If \c true, lookups should only return identifier from
1501	/// DeclContext scope (for example TranslationUnit). Used in
1502	/// LookupQualifiedName()
1503	LLVM_PREFERRED_TYPE(bool)
1504	mutable uint64_t UseQualifiedLookup : 1;
1505	};
1506
1507	/// Number of bits in DeclContextBitfields.
1508	enum { NumDeclContextBits = 13 };
1509
1510	/// Stores the bits used by NamespaceDecl.
1511	/// If modified NumNamespaceDeclBits and the accessor
1512	/// methods in NamespaceDecl should be updated appropriately.
1513	class NamespaceDeclBitfields {
1514	friend class NamespaceDecl;
1515	/// For the bits in DeclContextBitfields
1516	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1517	uint64_t : NumDeclContextBits;
1518
1519	/// True if this is an inline namespace.
1520	LLVM_PREFERRED_TYPE(bool)
1521	uint64_t IsInline : 1;
1522
1523	/// True if this is a nested-namespace-definition.
1524	LLVM_PREFERRED_TYPE(bool)
1525	uint64_t IsNested : 1;
1526	};
1527
1528	/// Number of inherited and non-inherited bits in NamespaceDeclBitfields.
1529	enum { NumNamespaceDeclBits = NumDeclContextBits + 2 };
1530
1531	/// Stores the bits used by TagDecl.
1532	/// If modified NumTagDeclBits and the accessor
1533	/// methods in TagDecl should be updated appropriately.
1534	class TagDeclBitfields {
1535	friend class TagDecl;
1536	/// For the bits in DeclContextBitfields
1537	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1538	uint64_t : NumDeclContextBits;
1539
1540	/// The TagKind enum.
1541	LLVM_PREFERRED_TYPE(TagTypeKind)
1542	uint64_t TagDeclKind : 3;
1543
1544	/// True if this is a definition ("struct foo {};"), false if it is a
1545	/// declaration ("struct foo;"). It is not considered a definition
1546	/// until the definition has been fully processed.
1547	LLVM_PREFERRED_TYPE(bool)
1548	uint64_t IsCompleteDefinition : 1;
1549
1550	/// True if this is currently being defined.
1551	LLVM_PREFERRED_TYPE(bool)
1552	uint64_t IsBeingDefined : 1;
1553
1554	/// True if this tag declaration is "embedded" (i.e., defined or declared
1555	/// for the very first time) in the syntax of a declarator.
1556	LLVM_PREFERRED_TYPE(bool)
1557	uint64_t IsEmbeddedInDeclarator : 1;
1558
1559	/// True if this tag is free standing, e.g. "struct foo;".
1560	LLVM_PREFERRED_TYPE(bool)
1561	uint64_t IsFreeStanding : 1;
1562
1563	/// Indicates whether it is possible for declarations of this kind
1564	/// to have an out-of-date definition.
1565	///
1566	/// This option is only enabled when modules are enabled.
1567	LLVM_PREFERRED_TYPE(bool)
1568	uint64_t MayHaveOutOfDateDef : 1;
1569
1570	/// Has the full definition of this type been required by a use somewhere in
1571	/// the TU.
1572	LLVM_PREFERRED_TYPE(bool)
1573	uint64_t IsCompleteDefinitionRequired : 1;
1574
1575	/// Whether this tag is a definition which was demoted due to
1576	/// a module merge.
1577	LLVM_PREFERRED_TYPE(bool)
1578	uint64_t IsThisDeclarationADemotedDefinition : 1;
1579	};
1580
1581	/// Number of inherited and non-inherited bits in TagDeclBitfields.
1582	enum { NumTagDeclBits = NumDeclContextBits + 10 };
1583
1584	/// Stores the bits used by EnumDecl.
1585	/// If modified NumEnumDeclBit and the accessor
1586	/// methods in EnumDecl should be updated appropriately.
1587	class EnumDeclBitfields {
1588	friend class EnumDecl;
1589	/// For the bits in TagDeclBitfields.
1590	LLVM_PREFERRED_TYPE(TagDeclBitfields)
1591	uint64_t : NumTagDeclBits;
1592
1593	/// Width in bits required to store all the non-negative
1594	/// enumerators of this enum.
1595	uint64_t NumPositiveBits : 8;
1596
1597	/// Width in bits required to store all the negative
1598	/// enumerators of this enum.
1599	uint64_t NumNegativeBits : 8;
1600
1601	/// True if this tag declaration is a scoped enumeration. Only
1602	/// possible in C++11 mode.
1603	LLVM_PREFERRED_TYPE(bool)
1604	uint64_t IsScoped : 1;
1605
1606	/// If this tag declaration is a scoped enum,
1607	/// then this is true if the scoped enum was declared using the class
1608	/// tag, false if it was declared with the struct tag. No meaning is
1609	/// associated if this tag declaration is not a scoped enum.
1610	LLVM_PREFERRED_TYPE(bool)
1611	uint64_t IsScopedUsingClassTag : 1;
1612
1613	/// True if this is an enumeration with fixed underlying type. Only
1614	/// possible in C++11, Microsoft extensions, or Objective C mode.
1615	LLVM_PREFERRED_TYPE(bool)
1616	uint64_t IsFixed : 1;
1617
1618	/// True if a valid hash is stored in ODRHash.
1619	LLVM_PREFERRED_TYPE(bool)
1620	uint64_t HasODRHash : 1;
1621	};
1622
1623	/// Number of inherited and non-inherited bits in EnumDeclBitfields.
1624	enum { NumEnumDeclBits = NumTagDeclBits + 20 };
1625
1626	/// Stores the bits used by RecordDecl.
1627	/// If modified NumRecordDeclBits and the accessor
1628	/// methods in RecordDecl should be updated appropriately.
1629	class RecordDeclBitfields {
1630	friend class RecordDecl;
1631	/// For the bits in TagDeclBitfields.
1632	LLVM_PREFERRED_TYPE(TagDeclBitfields)
1633	uint64_t : NumTagDeclBits;
1634
1635	/// This is true if this struct ends with a flexible
1636	/// array member (e.g. int X[]) or if this union contains a struct that does.
1637	/// If so, this cannot be contained in arrays or other structs as a member.
1638	LLVM_PREFERRED_TYPE(bool)
1639	uint64_t HasFlexibleArrayMember : 1;
1640
1641	/// Whether this is the type of an anonymous struct or union.
1642	LLVM_PREFERRED_TYPE(bool)
1643	uint64_t AnonymousStructOrUnion : 1;
1644
1645	/// This is true if this struct has at least one member
1646	/// containing an Objective-C object pointer type.
1647	LLVM_PREFERRED_TYPE(bool)
1648	uint64_t HasObjectMember : 1;
1649
1650	/// This is true if struct has at least one member of
1651	/// 'volatile' type.
1652	LLVM_PREFERRED_TYPE(bool)
1653	uint64_t HasVolatileMember : 1;
1654
1655	/// Whether the field declarations of this record have been loaded
1656	/// from external storage. To avoid unnecessary deserialization of
1657	/// methods/nested types we allow deserialization of just the fields
1658	/// when needed.
1659	LLVM_PREFERRED_TYPE(bool)
1660	mutable uint64_t LoadedFieldsFromExternalStorage : 1;
1661
1662	/// Basic properties of non-trivial C structs.
1663	LLVM_PREFERRED_TYPE(bool)
1664	uint64_t NonTrivialToPrimitiveDefaultInitialize : 1;
1665	LLVM_PREFERRED_TYPE(bool)
1666	uint64_t NonTrivialToPrimitiveCopy : 1;
1667	LLVM_PREFERRED_TYPE(bool)
1668	uint64_t NonTrivialToPrimitiveDestroy : 1;
1669
1670	/// The following bits indicate whether this is or contains a C union that
1671	/// is non-trivial to default-initialize, destruct, or copy. These bits
1672	/// imply the associated basic non-triviality predicates declared above.
1673	LLVM_PREFERRED_TYPE(bool)
1674	uint64_t HasNonTrivialToPrimitiveDefaultInitializeCUnion : 1;
1675	LLVM_PREFERRED_TYPE(bool)
1676	uint64_t HasNonTrivialToPrimitiveDestructCUnion : 1;
1677	LLVM_PREFERRED_TYPE(bool)
1678	uint64_t HasNonTrivialToPrimitiveCopyCUnion : 1;
1679
1680	/// True if any field is marked as requiring explicit initialization with
1681	/// [[clang::require_explicit_initialization]].
1682	/// In C++, this is also set for types without a user-provided default
1683	/// constructor, and is propagated from any base classes and/or member
1684	/// variables whose types are aggregates.
1685	LLVM_PREFERRED_TYPE(bool)
1686	uint64_t HasUninitializedExplicitInitFields : 1;
1687
1688	/// Indicates whether this struct is destroyed in the callee.
1689	LLVM_PREFERRED_TYPE(bool)
1690	uint64_t ParamDestroyedInCallee : 1;
1691
1692	/// Represents the way this type is passed to a function.
1693	LLVM_PREFERRED_TYPE(RecordArgPassingKind)
1694	uint64_t ArgPassingRestrictions : 2;
1695
1696	/// Indicates whether this struct has had its field layout randomized.
1697	LLVM_PREFERRED_TYPE(bool)
1698	uint64_t IsRandomized : 1;
1699
1700	/// True if a valid hash is stored in ODRHash. This should shave off some
1701	/// extra storage and prevent CXXRecordDecl to store unused bits.
1702	uint64_t ODRHash : NumOdrHashBits;
1703	};
1704
1705	/// Number of inherited and non-inherited bits in RecordDeclBitfields.
1706	enum { NumRecordDeclBits = NumTagDeclBits + 41 };
1707
1708	/// Stores the bits used by OMPDeclareReductionDecl.
1709	/// If modified NumOMPDeclareReductionDeclBits and the accessor
1710	/// methods in OMPDeclareReductionDecl should be updated appropriately.
1711	class OMPDeclareReductionDeclBitfields {
1712	friend class OMPDeclareReductionDecl;
1713	/// For the bits in DeclContextBitfields
1714	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1715	uint64_t : NumDeclContextBits;
1716
1717	/// Kind of initializer,
1718	/// function call or omp_priv<init_expr> initialization.
1719	LLVM_PREFERRED_TYPE(OMPDeclareReductionInitKind)
1720	uint64_t InitializerKind : 2;
1721	};
1722
1723	/// Number of inherited and non-inherited bits in
1724	/// OMPDeclareReductionDeclBitfields.
1725	enum { NumOMPDeclareReductionDeclBits = NumDeclContextBits + 2 };
1726
1727	/// Stores the bits used by FunctionDecl.
1728	/// If modified NumFunctionDeclBits and the accessor
1729	/// methods in FunctionDecl and CXXDeductionGuideDecl
1730	/// (for DeductionCandidateKind) should be updated appropriately.
1731	class FunctionDeclBitfields {
1732	friend class FunctionDecl;
1733	/// For DeductionCandidateKind
1734	friend class CXXDeductionGuideDecl;
1735	/// For the bits in DeclContextBitfields.
1736	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1737	uint64_t : NumDeclContextBits;
1738
1739	LLVM_PREFERRED_TYPE(StorageClass)
1740	uint64_t SClass : 3;
1741	LLVM_PREFERRED_TYPE(bool)
1742	uint64_t IsInline : 1;
1743	LLVM_PREFERRED_TYPE(bool)
1744	uint64_t IsInlineSpecified : 1;
1745
1746	LLVM_PREFERRED_TYPE(bool)
1747	uint64_t IsVirtualAsWritten : 1;
1748	LLVM_PREFERRED_TYPE(bool)
1749	uint64_t IsPureVirtual : 1;
1750	LLVM_PREFERRED_TYPE(bool)
1751	uint64_t HasInheritedPrototype : 1;
1752	LLVM_PREFERRED_TYPE(bool)
1753	uint64_t HasWrittenPrototype : 1;
1754	LLVM_PREFERRED_TYPE(bool)
1755	uint64_t IsDeleted : 1;
1756	/// Used by CXXMethodDecl
1757	LLVM_PREFERRED_TYPE(bool)
1758	uint64_t IsTrivial : 1;
1759
1760	/// This flag indicates whether this function is trivial for the purpose of
1761	/// calls. This is meaningful only when this function is a copy/move
1762	/// constructor or a destructor.
1763	LLVM_PREFERRED_TYPE(bool)
1764	uint64_t IsTrivialForCall : 1;
1765
1766	LLVM_PREFERRED_TYPE(bool)
1767	uint64_t IsDefaulted : 1;
1768	LLVM_PREFERRED_TYPE(bool)
1769	uint64_t IsExplicitlyDefaulted : 1;
1770	LLVM_PREFERRED_TYPE(bool)
1771	uint64_t HasDefaultedOrDeletedInfo : 1;
1772
1773	/// For member functions of complete types, whether this is an ineligible
1774	/// special member function or an unselected destructor. See
1775	/// [class.mem.special].
1776	LLVM_PREFERRED_TYPE(bool)
1777	uint64_t IsIneligibleOrNotSelected : 1;
1778
1779	LLVM_PREFERRED_TYPE(bool)
1780	uint64_t HasImplicitReturnZero : 1;
1781	LLVM_PREFERRED_TYPE(bool)
1782	uint64_t IsLateTemplateParsed : 1;
1783	LLVM_PREFERRED_TYPE(bool)
1784	uint64_t IsInstantiatedFromMemberTemplate : 1;
1785
1786	/// Kind of contexpr specifier as defined by ConstexprSpecKind.
1787	LLVM_PREFERRED_TYPE(ConstexprSpecKind)
1788	uint64_t ConstexprKind : 2;
1789	LLVM_PREFERRED_TYPE(bool)
1790	uint64_t BodyContainsImmediateEscalatingExpression : 1;
1791
1792	LLVM_PREFERRED_TYPE(bool)
1793	uint64_t InstantiationIsPending : 1;
1794
1795	/// Indicates if the function uses __try.
1796	LLVM_PREFERRED_TYPE(bool)
1797	uint64_t UsesSEHTry : 1;
1798
1799	/// Indicates if the function was a definition
1800	/// but its body was skipped.
1801	LLVM_PREFERRED_TYPE(bool)
1802	uint64_t HasSkippedBody : 1;
1803
1804	/// Indicates if the function declaration will
1805	/// have a body, once we're done parsing it.
1806	LLVM_PREFERRED_TYPE(bool)
1807	uint64_t WillHaveBody : 1;
1808
1809	/// Indicates that this function is a multiversioned
1810	/// function using attribute 'target'.
1811	LLVM_PREFERRED_TYPE(bool)
1812	uint64_t IsMultiVersion : 1;
1813
1814	/// Only used by CXXDeductionGuideDecl. Indicates the kind
1815	/// of the Deduction Guide that is implicitly generated
1816	/// (used during overload resolution).
1817	LLVM_PREFERRED_TYPE(DeductionCandidate)
1818	uint64_t DeductionCandidateKind : 2;
1819
1820	/// Store the ODRHash after first calculation.
1821	LLVM_PREFERRED_TYPE(bool)
1822	uint64_t HasODRHash : 1;
1823
1824	/// Indicates if the function uses Floating Point Constrained Intrinsics
1825	LLVM_PREFERRED_TYPE(bool)
1826	uint64_t UsesFPIntrin : 1;
1827
1828	// Indicates this function is a constrained friend, where the constraint
1829	// refers to an enclosing template for hte purposes of [temp.friend]p9.
1830	LLVM_PREFERRED_TYPE(bool)
1831	uint64_t FriendConstraintRefersToEnclosingTemplate : 1;
1832	};
1833
1834	/// Number of inherited and non-inherited bits in FunctionDeclBitfields.
1835	enum { NumFunctionDeclBits = NumDeclContextBits + 32 };
1836
1837	/// Stores the bits used by CXXConstructorDecl. If modified
1838	/// NumCXXConstructorDeclBits and the accessor
1839	/// methods in CXXConstructorDecl should be updated appropriately.
1840	class CXXConstructorDeclBitfields {
1841	friend class CXXConstructorDecl;
1842	/// For the bits in FunctionDeclBitfields.
1843	LLVM_PREFERRED_TYPE(FunctionDeclBitfields)
1844	uint64_t : NumFunctionDeclBits;
1845
1846	/// 19 bits to fit in the remaining available space.
1847	/// Note that this makes CXXConstructorDeclBitfields take
1848	/// exactly 64 bits and thus the width of NumCtorInitializers
1849	/// will need to be shrunk if some bit is added to NumDeclContextBitfields,
1850	/// NumFunctionDeclBitfields or CXXConstructorDeclBitfields.
1851	uint64_t NumCtorInitializers : 16;
1852	LLVM_PREFERRED_TYPE(bool)
1853	uint64_t IsInheritingConstructor : 1;
1854
1855	/// Whether this constructor has a trail-allocated explicit specifier.
1856	LLVM_PREFERRED_TYPE(bool)
1857	uint64_t HasTrailingExplicitSpecifier : 1;
1858	/// If this constructor does't have a trail-allocated explicit specifier.
1859	/// Whether this constructor is explicit specified.
1860	LLVM_PREFERRED_TYPE(bool)
1861	uint64_t IsSimpleExplicit : 1;
1862	};
1863
1864	/// Number of inherited and non-inherited bits in CXXConstructorDeclBitfields.
1865	enum { NumCXXConstructorDeclBits = NumFunctionDeclBits + 19 };
1866
1867	/// Stores the bits used by ObjCMethodDecl.
1868	/// If modified NumObjCMethodDeclBits and the accessor
1869	/// methods in ObjCMethodDecl should be updated appropriately.
1870	class ObjCMethodDeclBitfields {
1871	friend class ObjCMethodDecl;
1872
1873	/// For the bits in DeclContextBitfields.
1874	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1875	uint64_t : NumDeclContextBits;
1876
1877	/// The conventional meaning of this method; an ObjCMethodFamily.
1878	/// This is not serialized; instead, it is computed on demand and
1879	/// cached.
1880	LLVM_PREFERRED_TYPE(ObjCMethodFamily)
1881	mutable uint64_t Family : ObjCMethodFamilyBitWidth;
1882
1883	/// instance (true) or class (false) method.
1884	LLVM_PREFERRED_TYPE(bool)
1885	uint64_t IsInstance : 1;
1886	LLVM_PREFERRED_TYPE(bool)
1887	uint64_t IsVariadic : 1;
1888
1889	/// True if this method is the getter or setter for an explicit property.
1890	LLVM_PREFERRED_TYPE(bool)
1891	uint64_t IsPropertyAccessor : 1;
1892
1893	/// True if this method is a synthesized property accessor stub.
1894	LLVM_PREFERRED_TYPE(bool)
1895	uint64_t IsSynthesizedAccessorStub : 1;
1896
1897	/// Method has a definition.
1898	LLVM_PREFERRED_TYPE(bool)
1899	uint64_t IsDefined : 1;
1900
1901	/// Method redeclaration in the same interface.
1902	LLVM_PREFERRED_TYPE(bool)
1903	uint64_t IsRedeclaration : 1;
1904
1905	/// Is redeclared in the same interface.
1906	LLVM_PREFERRED_TYPE(bool)
1907	mutable uint64_t HasRedeclaration : 1;
1908
1909	/// \@required/\@optional
1910	LLVM_PREFERRED_TYPE(ObjCImplementationControl)
1911	uint64_t DeclImplementation : 2;
1912
1913	/// in, inout, etc.
1914	LLVM_PREFERRED_TYPE(Decl::ObjCDeclQualifier)
1915	uint64_t objcDeclQualifier : 7;
1916
1917	/// Indicates whether this method has a related result type.
1918	LLVM_PREFERRED_TYPE(bool)
1919	uint64_t RelatedResultType : 1;
1920
1921	/// Whether the locations of the selector identifiers are in a
1922	/// "standard" position, a enum SelectorLocationsKind.
1923	LLVM_PREFERRED_TYPE(SelectorLocationsKind)
1924	uint64_t SelLocsKind : 2;
1925
1926	/// Whether this method overrides any other in the class hierarchy.
1927	///
1928	/// A method is said to override any method in the class's
1929	/// base classes, its protocols, or its categories' protocols, that has
1930	/// the same selector and is of the same kind (class or instance).
1931	/// A method in an implementation is not considered as overriding the same
1932	/// method in the interface or its categories.
1933	LLVM_PREFERRED_TYPE(bool)
1934	uint64_t IsOverriding : 1;
1935
1936	/// Indicates if the method was a definition but its body was skipped.
1937	LLVM_PREFERRED_TYPE(bool)
1938	uint64_t HasSkippedBody : 1;
1939	};
1940
1941	/// Number of inherited and non-inherited bits in ObjCMethodDeclBitfields.
1942	enum { NumObjCMethodDeclBits = NumDeclContextBits + 24 };
1943
1944	/// Stores the bits used by ObjCContainerDecl.
1945	/// If modified NumObjCContainerDeclBits and the accessor
1946	/// methods in ObjCContainerDecl should be updated appropriately.
1947	class ObjCContainerDeclBitfields {
1948	friend class ObjCContainerDecl;
1949	/// For the bits in DeclContextBitfields
1950	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1951	uint32_t : NumDeclContextBits;
1952
1953	// Not a bitfield but this saves space.
1954	// Note that ObjCContainerDeclBitfields is full.
1955	SourceLocation AtStart;
1956	};
1957
1958	/// Number of inherited and non-inherited bits in ObjCContainerDeclBitfields.
1959	/// Note that here we rely on the fact that SourceLocation is 32 bits
1960	/// wide. We check this with the static_assert in the ctor of DeclContext.
1961	enum { NumObjCContainerDeclBits = 64 };
1962
1963	/// Stores the bits used by LinkageSpecDecl.
1964	/// If modified NumLinkageSpecDeclBits and the accessor
1965	/// methods in LinkageSpecDecl should be updated appropriately.
1966	class LinkageSpecDeclBitfields {
1967	friend class LinkageSpecDecl;
1968	/// For the bits in DeclContextBitfields.
1969	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1970	uint64_t : NumDeclContextBits;
1971
1972	/// The language for this linkage specification.
1973	LLVM_PREFERRED_TYPE(LinkageSpecLanguageIDs)
1974	uint64_t Language : 3;
1975
1976	/// True if this linkage spec has braces.
1977	/// This is needed so that hasBraces() returns the correct result while the
1978	/// linkage spec body is being parsed. Once RBraceLoc has been set this is
1979	/// not used, so it doesn't need to be serialized.
1980	LLVM_PREFERRED_TYPE(bool)
1981	uint64_t HasBraces : 1;
1982	};
1983
1984	/// Number of inherited and non-inherited bits in LinkageSpecDeclBitfields.
1985	enum { NumLinkageSpecDeclBits = NumDeclContextBits + 4 };
1986
1987	/// Stores the bits used by BlockDecl.
1988	/// If modified NumBlockDeclBits and the accessor
1989	/// methods in BlockDecl should be updated appropriately.
1990	class BlockDeclBitfields {
1991	friend class BlockDecl;
1992	/// For the bits in DeclContextBitfields.
1993	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1994	uint64_t : NumDeclContextBits;
1995
1996	LLVM_PREFERRED_TYPE(bool)
1997	uint64_t IsVariadic : 1;
1998	LLVM_PREFERRED_TYPE(bool)
1999	uint64_t CapturesCXXThis : 1;
2000	LLVM_PREFERRED_TYPE(bool)
2001	uint64_t BlockMissingReturnType : 1;
2002	LLVM_PREFERRED_TYPE(bool)
2003	uint64_t IsConversionFromLambda : 1;
2004
2005	/// A bit that indicates this block is passed directly to a function as a
2006	/// non-escaping parameter.
2007	LLVM_PREFERRED_TYPE(bool)
2008	uint64_t DoesNotEscape : 1;
2009
2010	/// A bit that indicates whether it's possible to avoid coying this block to
2011	/// the heap when it initializes or is assigned to a local variable with
2012	/// automatic storage.
2013	LLVM_PREFERRED_TYPE(bool)
2014	uint64_t CanAvoidCopyToHeap : 1;
2015	};
2016
2017	/// Number of inherited and non-inherited bits in BlockDeclBitfields.
2018	enum { NumBlockDeclBits = NumDeclContextBits + 5 };
2019
2020	/// Pointer to the data structure used to lookup declarations
2021	/// within this context (or a DependentStoredDeclsMap if this is a
2022	/// dependent context). We maintain the invariant that, if the map
2023	/// contains an entry for a DeclarationName (and we haven't lazily
2024	/// omitted anything), then it contains all relevant entries for that
2025	/// name (modulo the hasExternalDecls() flag).
2026	mutable StoredDeclsMap *LookupPtr = nullptr;
2027
2028	protected:
2029	/// This anonymous union stores the bits belonging to DeclContext and classes
2030	/// deriving from it. The goal is to use otherwise wasted
2031	/// space in DeclContext to store data belonging to derived classes.
2032	/// The space saved is especially significient when pointers are aligned
2033	/// to 8 bytes. In this case due to alignment requirements we have a
2034	/// little less than 8 bytes free in DeclContext which we can use.
2035	/// We check that none of the classes in this union is larger than
2036	/// 8 bytes with static_asserts in the ctor of DeclContext.
2037	union {
2038	DeclContextBitfields DeclContextBits;
2039	NamespaceDeclBitfields NamespaceDeclBits;
2040	TagDeclBitfields TagDeclBits;
2041	EnumDeclBitfields EnumDeclBits;
2042	RecordDeclBitfields RecordDeclBits;
2043	OMPDeclareReductionDeclBitfields OMPDeclareReductionDeclBits;
2044	FunctionDeclBitfields FunctionDeclBits;
2045	CXXConstructorDeclBitfields CXXConstructorDeclBits;
2046	ObjCMethodDeclBitfields ObjCMethodDeclBits;
2047	ObjCContainerDeclBitfields ObjCContainerDeclBits;
2048	LinkageSpecDeclBitfields LinkageSpecDeclBits;
2049	BlockDeclBitfields BlockDeclBits;
2050
2051	static_assert(sizeof(DeclContextBitfields) <= 8,
2052	"DeclContextBitfields is larger than 8 bytes!");
2053	static_assert(sizeof(NamespaceDeclBitfields) <= 8,
2054	"NamespaceDeclBitfields is larger than 8 bytes!");
2055	static_assert(sizeof(TagDeclBitfields) <= 8,
2056	"TagDeclBitfields is larger than 8 bytes!");
2057	static_assert(sizeof(EnumDeclBitfields) <= 8,
2058	"EnumDeclBitfields is larger than 8 bytes!");
2059	static_assert(sizeof(RecordDeclBitfields) <= 8,
2060	"RecordDeclBitfields is larger than 8 bytes!");
2061	static_assert(sizeof(OMPDeclareReductionDeclBitfields) <= 8,
2062	"OMPDeclareReductionDeclBitfields is larger than 8 bytes!");
2063	static_assert(sizeof(FunctionDeclBitfields) <= 8,
2064	"FunctionDeclBitfields is larger than 8 bytes!");
2065	static_assert(sizeof(CXXConstructorDeclBitfields) <= 8,
2066	"CXXConstructorDeclBitfields is larger than 8 bytes!");
2067	static_assert(sizeof(ObjCMethodDeclBitfields) <= 8,
2068	"ObjCMethodDeclBitfields is larger than 8 bytes!");
2069	static_assert(sizeof(ObjCContainerDeclBitfields) <= 8,
2070	"ObjCContainerDeclBitfields is larger than 8 bytes!");
2071	static_assert(sizeof(LinkageSpecDeclBitfields) <= 8,
2072	"LinkageSpecDeclBitfields is larger than 8 bytes!");
2073	static_assert(sizeof(BlockDeclBitfields) <= 8,
2074	"BlockDeclBitfields is larger than 8 bytes!");
2075	};
2076
2077	/// FirstDecl - The first declaration stored within this declaration
2078	/// context.
2079	mutable Decl *FirstDecl = nullptr;
2080
2081	/// LastDecl - The last declaration stored within this declaration
2082	/// context. FIXME: We could probably cache this value somewhere
2083	/// outside of the DeclContext, to reduce the size of DeclContext by
2084	/// another pointer.
2085	mutable Decl *LastDecl = nullptr;
2086
2087	/// Build up a chain of declarations.
2088	///
2089	/// \returns the first/last pair of declarations.
2090	static std::pair<Decl *, Decl *>
2091	BuildDeclChain(ArrayRef<Decl*> Decls, bool FieldsAlreadyLoaded);
2092
2093	DeclContext(Decl::Kind K);
2094
2095	public:
2096	~DeclContext();
2097
2098	// For use when debugging; hasValidDeclKind() will always return true for
2099	// a correctly constructed object within its lifetime.
2100	bool hasValidDeclKind() const;
2101
2102	Decl::Kind getDeclKind() const {
2103	return static_cast<Decl::Kind>(DeclContextBits.DeclKind);
2104	}
2105
2106	const char *getDeclKindName() const;
2107
2108	/// getParent - Returns the containing DeclContext.
2109	DeclContext *getParent() {
2110	return cast<Decl>(Val: this)->getDeclContext();
2111	}
2112	const DeclContext *getParent() const {
2113	return const_cast<DeclContext*>(this)->getParent();
2114	}
2115
2116	/// getLexicalParent - Returns the containing lexical DeclContext. May be
2117	/// different from getParent, e.g.:
2118	///
2119	/// namespace A {
2120	/// struct S;
2121	/// }
2122	/// struct A::S {}; // getParent() == namespace 'A'
2123	/// // getLexicalParent() == translation unit
2124	///
2125	DeclContext *getLexicalParent() {
2126	return cast<Decl>(Val: this)->getLexicalDeclContext();
2127	}
2128	const DeclContext *getLexicalParent() const {
2129	return const_cast<DeclContext*>(this)->getLexicalParent();
2130	}
2131
2132	DeclContext *getLookupParent();
2133
2134	const DeclContext *getLookupParent() const {
2135	return const_cast<DeclContext*>(this)->getLookupParent();
2136	}
2137
2138	ASTContext &getParentASTContext() const {
2139	return cast<Decl>(Val: this)->getASTContext();
2140	}
2141
2142	bool isClosure() const { return getDeclKind() == Decl::Block; }
2143
2144	/// Return this DeclContext if it is a BlockDecl. Otherwise, return the
2145	/// innermost enclosing BlockDecl or null if there are no enclosing blocks.
2146	const BlockDecl *getInnermostBlockDecl() const;
2147
2148	bool isObjCContainer() const {
2149	switch (getDeclKind()) {
2150	case Decl::ObjCCategory:
2151	case Decl::ObjCCategoryImpl:
2152	case Decl::ObjCImplementation:
2153	case Decl::ObjCInterface:
2154	case Decl::ObjCProtocol:
2155	return true;
2156	default:
2157	return false;
2158	}
2159	}
2160
2161	bool isFunctionOrMethod() const {
2162	switch (getDeclKind()) {
2163	case Decl::Block:
2164	case Decl::Captured:
2165	case Decl::ObjCMethod:
2166	case Decl::TopLevelStmt:
2167	return true;
2168	default:
2169	return getDeclKind() >= Decl::firstFunction &&
2170	getDeclKind() <= Decl::lastFunction;
2171	}
2172	}
2173
2174	/// Test whether the context supports looking up names.
2175	bool isLookupContext() const {
2176	return !isFunctionOrMethod() && getDeclKind() != Decl::LinkageSpec &&
2177	getDeclKind() != Decl::Export;
2178	}
2179
2180	bool isFileContext() const {
2181	return getDeclKind() == Decl::TranslationUnit ||
2182	getDeclKind() == Decl::Namespace;
2183	}
2184
2185	bool isTranslationUnit() const {
2186	return getDeclKind() == Decl::TranslationUnit;
2187	}
2188
2189	bool isRecord() const {
2190	return getDeclKind() >= Decl::firstRecord &&
2191	getDeclKind() <= Decl::lastRecord;
2192	}
2193
2194	bool isRequiresExprBody() const {
2195	return getDeclKind() == Decl::RequiresExprBody;
2196	}
2197
2198	bool isNamespace() const { return getDeclKind() == Decl::Namespace; }
2199
2200	bool isStdNamespace() const;
2201
2202	bool isInlineNamespace() const;
2203
2204	/// Determines whether this context is dependent on a
2205	/// template parameter.
2206	bool isDependentContext() const;
2207
2208	/// isTransparentContext - Determines whether this context is a
2209	/// "transparent" context, meaning that the members declared in this
2210	/// context are semantically declared in the nearest enclosing
2211	/// non-transparent (opaque) context but are lexically declared in
2212	/// this context. For example, consider the enumerators of an
2213	/// enumeration type:
2214	/// @code
2215	/// enum E {
2216	/// Val1
2217	/// };
2218	/// @endcode
2219	/// Here, E is a transparent context, so its enumerator (Val1) will
2220	/// appear (semantically) that it is in the same context of E.
2221	/// Examples of transparent contexts include: enumerations (except for
2222	/// C++0x scoped enums), C++ linkage specifications and export declaration.
2223	bool isTransparentContext() const;
2224
2225	/// Determines whether this context or some of its ancestors is a
2226	/// linkage specification context that specifies C linkage.
2227	bool isExternCContext() const;
2228
2229	/// Retrieve the nearest enclosing C linkage specification context.
2230	const LinkageSpecDecl *getExternCContext() const;
2231
2232	/// Determines whether this context or some of its ancestors is a
2233	/// linkage specification context that specifies C++ linkage.
2234	bool isExternCXXContext() const;
2235
2236	/// Determine whether this declaration context is equivalent
2237	/// to the declaration context DC.
2238	bool Equals(const DeclContext *DC) const {
2239	return DC && this->getPrimaryContext() == DC->getPrimaryContext();
2240	}
2241
2242	/// Determine whether this declaration context semantically encloses the
2243	/// declaration context DC.
2244	bool Encloses(const DeclContext *DC) const;
2245
2246	/// Determine whether this declaration context lexically encloses the
2247	/// declaration context DC.
2248	bool LexicallyEncloses(const DeclContext *DC) const;
2249
2250	/// Find the nearest non-closure ancestor of this context,
2251	/// i.e. the innermost semantic parent of this context which is not
2252	/// a closure. A context may be its own non-closure ancestor.
2253	Decl *getNonClosureAncestor();
2254	const Decl *getNonClosureAncestor() const {
2255	return const_cast<DeclContext*>(this)->getNonClosureAncestor();
2256	}
2257
2258	// Retrieve the nearest context that is not a transparent context.
2259	DeclContext *getNonTransparentContext();
2260	const DeclContext *getNonTransparentContext() const {
2261	return const_cast<DeclContext *>(this)->getNonTransparentContext();
2262	}
2263
2264	/// getPrimaryContext - There may be many different
2265	/// declarations of the same entity (including forward declarations
2266	/// of classes, multiple definitions of namespaces, etc.), each with
2267	/// a different set of declarations. This routine returns the
2268	/// "primary" DeclContext structure, which will contain the
2269	/// information needed to perform name lookup into this context.
2270	DeclContext *getPrimaryContext();
2271	const DeclContext *getPrimaryContext() const {
2272	return const_cast<DeclContext*>(this)->getPrimaryContext();
2273	}
2274
2275	/// getRedeclContext - Retrieve the context in which an entity conflicts with
2276	/// other entities of the same name, or where it is a redeclaration if the
2277	/// two entities are compatible. This skips through transparent contexts.
2278	DeclContext *getRedeclContext();
2279	const DeclContext *getRedeclContext() const {
2280	return const_cast<DeclContext *>(this)->getRedeclContext();
2281	}
2282
2283	/// Retrieve the nearest enclosing namespace context.
2284	DeclContext *getEnclosingNamespaceContext();
2285	const DeclContext *getEnclosingNamespaceContext() const {
2286	return const_cast<DeclContext *>(this)->getEnclosingNamespaceContext();
2287	}
2288
2289	/// Retrieve the outermost lexically enclosing record context.
2290	RecordDecl *getOuterLexicalRecordContext();
2291	const RecordDecl *getOuterLexicalRecordContext() const {
2292	return const_cast<DeclContext *>(this)->getOuterLexicalRecordContext();
2293	}
2294
2295	/// Test if this context is part of the enclosing namespace set of
2296	/// the context NS, as defined in C++0x [namespace.def]p9. If either context
2297	/// isn't a namespace, this is equivalent to Equals().
2298	///
2299	/// The enclosing namespace set of a namespace is the namespace and, if it is
2300	/// inline, its enclosing namespace, recursively.
2301	bool InEnclosingNamespaceSetOf(const DeclContext *NS) const;
2302
2303	/// Collects all of the declaration contexts that are semantically
2304	/// connected to this declaration context.
2305	///
2306	/// For declaration contexts that have multiple semantically connected but
2307	/// syntactically distinct contexts, such as C++ namespaces, this routine
2308	/// retrieves the complete set of such declaration contexts in source order.
2309	/// For example, given:
2310	///
2311	/// \code
2312	/// namespace N {
2313	/// int x;
2314	/// }
2315	/// namespace N {
2316	/// int y;
2317	/// }
2318	/// \endcode
2319	///
2320	/// The \c Contexts parameter will contain both definitions of N.
2321	///
2322	/// \param Contexts Will be cleared and set to the set of declaration
2323	/// contexts that are semanticaly connected to this declaration context,
2324	/// in source order, including this context (which may be the only result,
2325	/// for non-namespace contexts).
2326	void collectAllContexts(SmallVectorImpl<DeclContext *> &Contexts);
2327
2328	/// decl_iterator - Iterates through the declarations stored
2329	/// within this context.
2330	class decl_iterator {
2331	/// Current - The current declaration.
2332	Decl *Current = nullptr;
2333
2334	public:
2335	using value_type = Decl *;
2336	using reference = const value_type &;
2337	using pointer = const value_type *;
2338	using iterator_category = std::forward_iterator_tag;
2339	using difference_type = std::ptrdiff_t;
2340
2341	decl_iterator() = default;
2342	explicit decl_iterator(Decl *C) : Current(C) {}
2343
2344	reference operator*() const { return Current; }
2345
2346	// This doesn't meet the iterator requirements, but it's convenient
2347	value_type operator->() const { return Current; }
2348
2349	decl_iterator& operator++() {
2350	Current = Current->getNextDeclInContext();
2351	return *this;
2352	}
2353
2354	decl_iterator operator++(int) {
2355	decl_iterator tmp(*this);
2356	++(*this);
2357	return tmp;
2358	}
2359
2360	friend bool operator==(decl_iterator x, decl_iterator y) {
2361	return x.Current == y.Current;
2362	}
2363
2364	friend bool operator!=(decl_iterator x, decl_iterator y) {
2365	return x.Current != y.Current;
2366	}
2367	};
2368
2369	using decl_range = llvm::iterator_range<decl_iterator>;
2370
2371	/// decls_begin/decls_end - Iterate over the declarations stored in
2372	/// this context.
2373	decl_range decls() const { return decl_range(decls_begin(), decls_end()); }
2374	decl_iterator decls_begin() const;
2375	decl_iterator decls_end() const { return decl_iterator(); }
2376	bool decls_empty() const;
2377
2378	/// noload_decls_begin/end - Iterate over the declarations stored in this
2379	/// context that are currently loaded; don't attempt to retrieve anything
2380	/// from an external source.
2381	decl_range noload_decls() const {
2382	return decl_range(noload_decls_begin(), noload_decls_end());
2383	}
2384	decl_iterator noload_decls_begin() const { return decl_iterator(FirstDecl); }
2385	decl_iterator noload_decls_end() const { return decl_iterator(); }
2386
2387	/// specific_decl_iterator - Iterates over a subrange of
2388	/// declarations stored in a DeclContext, providing only those that
2389	/// are of type SpecificDecl (or a class derived from it). This
2390	/// iterator is used, for example, to provide iteration over just
2391	/// the fields within a RecordDecl (with SpecificDecl = FieldDecl).
2392	template<typename SpecificDecl>
2393	class specific_decl_iterator {
2394	/// Current - The current, underlying declaration iterator, which
2395	/// will either be NULL or will point to a declaration of
2396	/// type SpecificDecl.
2397	DeclContext::decl_iterator Current;
2398
2399	/// SkipToNextDecl - Advances the current position up to the next
2400	/// declaration of type SpecificDecl that also meets the criteria
2401	/// required by Acceptable.
2402	void SkipToNextDecl() {
2403	while (*Current && !isa<SpecificDecl>(*Current))
2404	++Current;
2405	}
2406
2407	public:
2408	using value_type = SpecificDecl *;
2409	// TODO: Add reference and pointer types (with some appropriate proxy type)
2410	// if we ever have a need for them.
2411	using reference = void;
2412	using pointer = void;
2413	using difference_type =
2414	std::iterator_traits<DeclContext::decl_iterator>::difference_type;
2415	using iterator_category = std::forward_iterator_tag;
2416
2417	specific_decl_iterator() = default;
2418
2419	/// specific_decl_iterator - Construct a new iterator over a
2420	/// subset of the declarations the range [C,
2421	/// end-of-declarations). If A is non-NULL, it is a pointer to a
2422	/// member function of SpecificDecl that should return true for
2423	/// all of the SpecificDecl instances that will be in the subset
2424	/// of iterators. For example, if you want Objective-C instance
2425	/// methods, SpecificDecl will be ObjCMethodDecl and A will be
2426	/// &ObjCMethodDecl::isInstanceMethod.
2427	explicit specific_decl_iterator(DeclContext::decl_iterator C) : Current(C) {
2428	SkipToNextDecl();
2429	}
2430
2431	value_type operator*() const { return cast<SpecificDecl>(*Current); }
2432
2433	// This doesn't meet the iterator requirements, but it's convenient
2434	value_type operator->() const { return **this; }
2435
2436	specific_decl_iterator& operator++() {
2437	++Current;
2438	SkipToNextDecl();
2439	return *this;
2440	}
2441
2442	specific_decl_iterator operator++(int) {
2443	specific_decl_iterator tmp(*this);
2444	++(*this);
2445	return tmp;
2446	}
2447
2448	friend bool operator==(const specific_decl_iterator& x,
2449	const specific_decl_iterator& y) {
2450	return x.Current == y.Current;
2451	}
2452
2453	friend bool operator!=(const specific_decl_iterator& x,
2454	const specific_decl_iterator& y) {
2455	return x.Current != y.Current;
2456	}
2457	};
2458
2459	/// Iterates over a filtered subrange of declarations stored
2460	/// in a DeclContext.
2461	///
2462	/// This iterator visits only those declarations that are of type
2463	/// SpecificDecl (or a class derived from it) and that meet some
2464	/// additional run-time criteria. This iterator is used, for
2465	/// example, to provide access to the instance methods within an
2466	/// Objective-C interface (with SpecificDecl = ObjCMethodDecl and
2467	/// Acceptable = ObjCMethodDecl::isInstanceMethod).
2468	template<typename SpecificDecl, bool (SpecificDecl::*Acceptable)() const>
2469	class filtered_decl_iterator {
2470	/// Current - The current, underlying declaration iterator, which
2471	/// will either be NULL or will point to a declaration of
2472	/// type SpecificDecl.
2473	DeclContext::decl_iterator Current;
2474
2475	/// SkipToNextDecl - Advances the current position up to the next
2476	/// declaration of type SpecificDecl that also meets the criteria
2477	/// required by Acceptable.
2478	void SkipToNextDecl() {
2479	while (*Current &&
2480	(!isa<SpecificDecl>(*Current) ||
2481	(Acceptable && !(cast<SpecificDecl>(*Current)->*Acceptable)())))
2482	++Current;
2483	}
2484
2485	public:
2486	using value_type = SpecificDecl *;
2487	// TODO: Add reference and pointer types (with some appropriate proxy type)
2488	// if we ever have a need for them.
2489	using reference = void;
2490	using pointer = void;
2491	using difference_type =
2492	std::iterator_traits<DeclContext::decl_iterator>::difference_type;
2493	using iterator_category = std::forward_iterator_tag;
2494
2495	filtered_decl_iterator() = default;
2496
2497	/// filtered_decl_iterator - Construct a new iterator over a
2498	/// subset of the declarations the range [C,
2499	/// end-of-declarations). If A is non-NULL, it is a pointer to a
2500	/// member function of SpecificDecl that should return true for
2501	/// all of the SpecificDecl instances that will be in the subset
2502	/// of iterators. For example, if you want Objective-C instance
2503	/// methods, SpecificDecl will be ObjCMethodDecl and A will be
2504	/// &ObjCMethodDecl::isInstanceMethod.
2505	explicit filtered_decl_iterator(DeclContext::decl_iterator C) : Current(C) {
2506	SkipToNextDecl();
2507	}
2508
2509	value_type operator*() const { return cast<SpecificDecl>(*Current); }
2510	value_type operator->() const { return cast<SpecificDecl>(*Current); }
2511
2512	filtered_decl_iterator& operator++() {
2513	++Current;
2514	SkipToNextDecl();
2515	return *this;
2516	}
2517
2518	filtered_decl_iterator operator++(int) {
2519	filtered_decl_iterator tmp(*this);
2520	++(*this);
2521	return tmp;
2522	}
2523
2524	friend bool operator==(const filtered_decl_iterator& x,
2525	const filtered_decl_iterator& y) {
2526	return x.Current == y.Current;
2527	}
2528
2529	friend bool operator!=(const filtered_decl_iterator& x,
2530	const filtered_decl_iterator& y) {
2531	return x.Current != y.Current;
2532	}
2533	};
2534
2535	/// Add the declaration D into this context.
2536	///
2537	/// This routine should be invoked when the declaration D has first
2538	/// been declared, to place D into the context where it was
2539	/// (lexically) defined. Every declaration must be added to one
2540	/// (and only one!) context, where it can be visited via
2541	/// [decls_begin(), decls_end()). Once a declaration has been added
2542	/// to its lexical context, the corresponding DeclContext owns the
2543	/// declaration.
2544	///
2545	/// If D is also a NamedDecl, it will be made visible within its
2546	/// semantic context via makeDeclVisibleInContext.
2547	void addDecl(Decl *D);
2548
2549	/// Add the declaration D into this context, but suppress
2550	/// searches for external declarations with the same name.
2551	///
2552	/// Although analogous in function to addDecl, this removes an
2553	/// important check. This is only useful if the Decl is being
2554	/// added in response to an external search; in all other cases,
2555	/// addDecl() is the right function to use.
2556	/// See the ASTImporter for use cases.
2557	void addDeclInternal(Decl *D);
2558
2559	/// Add the declaration D to this context without modifying
2560	/// any lookup tables.
2561	///
2562	/// This is useful for some operations in dependent contexts where
2563	/// the semantic context might not be dependent; this basically
2564	/// only happens with friends.
2565	void addHiddenDecl(Decl *D);
2566
2567	/// Removes a declaration from this context.
2568	void removeDecl(Decl *D);
2569
2570	/// Checks whether a declaration is in this context.
2571	bool containsDecl(Decl *D) const;
2572
2573	/// Checks whether a declaration is in this context.
2574	/// This also loads the Decls from the external source before the check.
2575	bool containsDeclAndLoad(Decl *D) const;
2576
2577	using lookup_result = DeclContextLookupResult;
2578	using lookup_iterator = lookup_result::iterator;
2579
2580	/// lookup - Find the declarations (if any) with the given Name in
2581	/// this context. Returns a range of iterators that contains all of
2582	/// the declarations with this name, with object, function, member,
2583	/// and enumerator names preceding any tag name. Note that this
2584	/// routine will not look into parent contexts.
2585	lookup_result lookup(DeclarationName Name) const;
2586
2587	/// Find the declarations with the given name that are visible
2588	/// within this context; don't attempt to retrieve anything from an
2589	/// external source.
2590	lookup_result noload_lookup(DeclarationName Name);
2591
2592	/// A simplistic name lookup mechanism that performs name lookup
2593	/// into this declaration context without consulting the external source.
2594	///
2595	/// This function should almost never be used, because it subverts the
2596	/// usual relationship between a DeclContext and the external source.
2597	/// See the ASTImporter for the (few, but important) use cases.
2598	///
2599	/// FIXME: This is very inefficient; replace uses of it with uses of
2600	/// noload_lookup.
2601	void localUncachedLookup(DeclarationName Name,
2602	SmallVectorImpl<NamedDecl *> &Results);
2603
2604	/// Makes a declaration visible within this context.
2605	///
2606	/// This routine makes the declaration D visible to name lookup
2607	/// within this context and, if this is a transparent context,
2608	/// within its parent contexts up to the first enclosing
2609	/// non-transparent context. Making a declaration visible within a
2610	/// context does not transfer ownership of a declaration, and a
2611	/// declaration can be visible in many contexts that aren't its
2612	/// lexical context.
2613	///
2614	/// If D is a redeclaration of an existing declaration that is
2615	/// visible from this context, as determined by
2616	/// NamedDecl::declarationReplaces, the previous declaration will be
2617	/// replaced with D.
2618	void makeDeclVisibleInContext(NamedDecl *D);
2619
2620	/// all_lookups_iterator - An iterator that provides a view over the results
2621	/// of looking up every possible name.
2622	class all_lookups_iterator;
2623
2624	using lookups_range = llvm::iterator_range<all_lookups_iterator>;
2625
2626	lookups_range lookups() const;
2627	// Like lookups(), but avoids loading external declarations.
2628	// If PreserveInternalState, avoids building lookup data structures too.
2629	lookups_range noload_lookups(bool PreserveInternalState) const;
2630
2631	/// Iterators over all possible lookups within this context.
2632	all_lookups_iterator lookups_begin() const;
2633	all_lookups_iterator lookups_end() const;
2634
2635	/// Iterators over all possible lookups within this context that are
2636	/// currently loaded; don't attempt to retrieve anything from an external
2637	/// source.
2638	all_lookups_iterator noload_lookups_begin() const;
2639	all_lookups_iterator noload_lookups_end() const;
2640
2641	struct udir_iterator;
2642
2643	using udir_iterator_base =
2644	llvm::iterator_adaptor_base<udir_iterator, lookup_iterator,
2645	typename lookup_iterator::iterator_category,
2646	UsingDirectiveDecl *>;
2647
2648	struct udir_iterator : udir_iterator_base {
2649	udir_iterator(lookup_iterator I) : udir_iterator_base(I) {}
2650
2651	UsingDirectiveDecl *operator*() const;
2652	};
2653
2654	using udir_range = llvm::iterator_range<udir_iterator>;
2655
2656	udir_range using_directives() const;
2657
2658	// These are all defined in DependentDiagnostic.h.
2659	class ddiag_iterator;
2660
2661	using ddiag_range = llvm::iterator_range<DeclContext::ddiag_iterator>;
2662
2663	inline ddiag_range ddiags() const;
2664
2665	// Low-level accessors
2666
2667	/// Mark that there are external lexical declarations that we need
2668	/// to include in our lookup table (and that are not available as external
2669	/// visible lookups). These extra lookup results will be found by walking
2670	/// the lexical declarations of this context. This should be used only if
2671	/// setHasExternalLexicalStorage() has been called on any decl context for
2672	/// which this is the primary context.
2673	void setMustBuildLookupTable() {
2674	assert(this == getPrimaryContext() &&
2675	"should only be called on primary context");
2676	DeclContextBits.HasLazyExternalLexicalLookups = true;
2677	}
2678
2679	/// Retrieve the internal representation of the lookup structure.
2680	/// This may omit some names if we are lazily building the structure.
2681	StoredDeclsMap *getLookupPtr() const { return LookupPtr; }
2682
2683	/// Ensure the lookup structure is fully-built and return it.
2684	StoredDeclsMap *buildLookup();
2685
2686	/// Whether this DeclContext has external storage containing
2687	/// additional declarations that are lexically in this context.
2688	bool hasExternalLexicalStorage() const {
2689	return DeclContextBits.ExternalLexicalStorage;
2690	}
2691
2692	/// State whether this DeclContext has external storage for
2693	/// declarations lexically in this context.
2694	void setHasExternalLexicalStorage(bool ES = true) const {
2695	DeclContextBits.ExternalLexicalStorage = ES;
2696	}
2697
2698	/// Whether this DeclContext has external storage containing
2699	/// additional declarations that are visible in this context.
2700	bool hasExternalVisibleStorage() const {
2701	return DeclContextBits.ExternalVisibleStorage;
2702	}
2703
2704	/// State whether this DeclContext has external storage for
2705	/// declarations visible in this context.
2706	void setHasExternalVisibleStorage(bool ES = true) const {
2707	DeclContextBits.ExternalVisibleStorage = ES;
2708	if (ES && LookupPtr)
2709	DeclContextBits.NeedToReconcileExternalVisibleStorage = true;
2710	}
2711
2712	/// Determine whether the given declaration is stored in the list of
2713	/// declarations lexically within this context.
2714	bool isDeclInLexicalTraversal(const Decl *D) const {
2715	return D && (D->NextInContextAndBits.getPointer() || D == FirstDecl ||
2716	D == LastDecl);
2717	}
2718
2719	void setUseQualifiedLookup(bool use = true) const {
2720	DeclContextBits.UseQualifiedLookup = use;
2721	}
2722
2723	bool shouldUseQualifiedLookup() const {
2724	return DeclContextBits.UseQualifiedLookup;
2725	}
2726
2727	static bool classof(const Decl *D);
2728	static bool classof(const DeclContext *D) { return true; }
2729
2730	void dumpAsDecl() const;
2731	void dumpAsDecl(const ASTContext *Ctx) const;
2732	void dumpDeclContext() const;
2733	void dumpLookups() const;
2734	void dumpLookups(llvm::raw_ostream &OS, bool DumpDecls = false,
2735	bool Deserialize = false) const;
2736
2737	private:
2738	lookup_result lookupImpl(DeclarationName Name,
2739	const DeclContext *OriginalLookupDC) const;
2740
2741	/// Whether this declaration context has had externally visible
2742	/// storage added since the last lookup. In this case, \c LookupPtr's
2743	/// invariant may not hold and needs to be fixed before we perform
2744	/// another lookup.
2745	bool hasNeedToReconcileExternalVisibleStorage() const {
2746	return DeclContextBits.NeedToReconcileExternalVisibleStorage;
2747	}
2748
2749	/// State that this declaration context has had externally visible
2750	/// storage added since the last lookup. In this case, \c LookupPtr's
2751	/// invariant may not hold and needs to be fixed before we perform
2752	/// another lookup.
2753	void setNeedToReconcileExternalVisibleStorage(bool Need = true) const {
2754	DeclContextBits.NeedToReconcileExternalVisibleStorage = Need;
2755	}
2756
2757	/// If \c true, this context may have local lexical declarations
2758	/// that are missing from the lookup table.
2759	bool hasLazyLocalLexicalLookups() const {
2760	return DeclContextBits.HasLazyLocalLexicalLookups;
2761	}
2762
2763	/// If \c true, this context may have local lexical declarations
2764	/// that are missing from the lookup table.
2765	void setHasLazyLocalLexicalLookups(bool HasLLLL = true) const {
2766	DeclContextBits.HasLazyLocalLexicalLookups = HasLLLL;
2767	}
2768
2769	/// If \c true, the external source may have lexical declarations
2770	/// that are missing from the lookup table.
2771	bool hasLazyExternalLexicalLookups() const {
2772	return DeclContextBits.HasLazyExternalLexicalLookups;
2773	}
2774
2775	/// If \c true, the external source may have lexical declarations
2776	/// that are missing from the lookup table.
2777	void setHasLazyExternalLexicalLookups(bool HasLELL = true) const {
2778	DeclContextBits.HasLazyExternalLexicalLookups = HasLELL;
2779	}
2780
2781	void reconcileExternalVisibleStorage() const;
2782	bool LoadLexicalDeclsFromExternalStorage() const;
2783
2784	StoredDeclsMap *CreateStoredDeclsMap(ASTContext &C) const;
2785
2786	void loadLazyLocalLexicalLookups();
2787	void buildLookupImpl(DeclContext *DCtx, bool Internal);
2788	void makeDeclVisibleInContextWithFlags(NamedDecl *D, bool Internal,
2789	bool Rediscoverable);
2790	void makeDeclVisibleInContextImpl(NamedDecl *D, bool Internal);
2791	};
2792
2793	inline bool Decl::isTemplateParameter() const {
2794	return getKind() == TemplateTypeParm || getKind() == NonTypeTemplateParm ||
2795	getKind() == TemplateTemplateParm;
2796	}
2797
2798	// Specialization selected when ToTy is not a known subclass of DeclContext.
2799	template <class ToTy,
2800	bool IsKnownSubtype = ::std::is_base_of<DeclContext, ToTy>::value>
2801	struct cast_convert_decl_context {
2802	static const ToTy *doit(const DeclContext *Val) {
2803	return static_cast<const ToTy*>(Decl::castFromDeclContext(Val));
2804	}
2805
2806	static ToTy *doit(DeclContext *Val) {
2807	return static_cast<ToTy*>(Decl::castFromDeclContext(Val));
2808	}
2809	};
2810
2811	// Specialization selected when ToTy is a known subclass of DeclContext.
2812	template <class ToTy>
2813	struct cast_convert_decl_context<ToTy, true> {
2814	static const ToTy *doit(const DeclContext *Val) {
2815	return static_cast<const ToTy*>(Val);
2816	}
2817
2818	static ToTy *doit(DeclContext *Val) {
2819	return static_cast<ToTy*>(Val);
2820	}
2821	};
2822
2823	} // namespace clang
2824
2825	namespace llvm {
2826
2827	/// isa<T>(DeclContext*)
2828	template <typename To>
2829	struct isa_impl<To, ::clang::DeclContext> {
2830	static bool doit(const ::clang::DeclContext &Val) {
2831	return To::classofKind(Val.getDeclKind());
2832	}
2833	};
2834
2835	/// cast<T>(DeclContext*)
2836	template<class ToTy>
2837	struct cast_convert_val<ToTy,
2838	const ::clang::DeclContext,const ::clang::DeclContext> {
2839	static const ToTy &doit(const ::clang::DeclContext &Val) {
2840	return *::clang::cast_convert_decl_context<ToTy>::doit(&Val);
2841	}
2842	};
2843
2844	template<class ToTy>
2845	struct cast_convert_val<ToTy, ::clang::DeclContext, ::clang::DeclContext> {
2846	static ToTy &doit(::clang::DeclContext &Val) {
2847	return *::clang::cast_convert_decl_context<ToTy>::doit(&Val);
2848	}
2849	};
2850
2851	template<class ToTy>
2852	struct cast_convert_val<ToTy,
2853	const ::clang::DeclContext*, const ::clang::DeclContext*> {
2854	static const ToTy *doit(const ::clang::DeclContext *Val) {
2855	return ::clang::cast_convert_decl_context<ToTy>::doit(Val);
2856	}
2857	};
2858
2859	template<class ToTy>
2860	struct cast_convert_val<ToTy, ::clang::DeclContext*, ::clang::DeclContext*> {
2861	static ToTy *doit(::clang::DeclContext *Val) {
2862	return ::clang::cast_convert_decl_context<ToTy>::doit(Val);
2863	}
2864	};
2865
2866	/// Implement cast_convert_val for Decl -> DeclContext conversions.
2867	template<class FromTy>
2868	struct cast_convert_val< ::clang::DeclContext, FromTy, FromTy> {
2869	static ::clang::DeclContext &doit(const FromTy &Val) {
2870	return *FromTy::castToDeclContext(&Val);
2871	}
2872	};
2873
2874	template<class FromTy>
2875	struct cast_convert_val< ::clang::DeclContext, FromTy*, FromTy*> {
2876	static ::clang::DeclContext *doit(const FromTy *Val) {
2877	return FromTy::castToDeclContext(Val);
2878	}
2879	};
2880
2881	template<class FromTy>
2882	struct cast_convert_val< const ::clang::DeclContext, FromTy, FromTy> {
2883	static const ::clang::DeclContext &doit(const FromTy &Val) {
2884	return *FromTy::castToDeclContext(&Val);
2885	}
2886	};
2887
2888	template<class FromTy>
2889	struct cast_convert_val< const ::clang::DeclContext, FromTy*, FromTy*> {
2890	static const ::clang::DeclContext *doit(const FromTy *Val) {
2891	return FromTy::castToDeclContext(Val);
2892	}
2893	};
2894
2895	} // namespace llvm
2896
2897	#endif // LLVM_CLANG_AST_DECLBASE_H
2898