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 *>(Val: DeclCtx); }
275	bool isOutOfSemaDC() const { return isa<MultipleDC *>(Val: DeclCtx); }
276
277	MultipleDC *getMultipleDC() const { return cast<MultipleDC *>(Val: DeclCtx); }
278
279	DeclContext *getSemanticDC() const { return cast<DeclContext *>(Val: 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>(Val: 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(E: 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(E: 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(E: 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 a local declaration to a C++20
650	/// named module.
651	bool isModuleLocal() const;
652
653	/// Whether this declaration was exported in a lexical context.
654	/// e.g.:
655	///
656	/// export namespace A {
657	/// void f1(); // isInExportDeclContext() == true
658	/// }
659	/// void A::f1(); // isInExportDeclContext() == false
660	///
661	/// namespace B {
662	/// void f2(); // isInExportDeclContext() == false
663	/// }
664	/// export void B::f2(); // isInExportDeclContext() == true
665	bool isInExportDeclContext() const;
666
667	bool isInvisibleOutsideTheOwningModule() const {
668	return getModuleOwnershipKind() > ModuleOwnershipKind::VisibleWhenImported;
669	}
670
671	/// Whether this declaration comes from another module unit.
672	bool isInAnotherModuleUnit() const;
673
674	/// Whether this declaration comes from the same module unit being compiled.
675	bool isInCurrentModuleUnit() const;
676
677	/// Whether the definition of the declaration should be emitted in external
678	/// sources.
679	bool shouldEmitInExternalSource() const;
680
681	/// Whether this declaration comes from explicit global module.
682	bool isFromExplicitGlobalModule() const;
683
684	/// Whether this declaration comes from global module.
685	bool isFromGlobalModule() const;
686
687	/// Whether this declaration comes from a named module.
688	bool isInNamedModule() const;
689
690	/// Whether this declaration comes from a header unit.
691	bool isFromHeaderUnit() const;
692
693	/// Return true if this declaration has an attribute which acts as
694	/// definition of the entity, such as 'alias' or 'ifunc'.
695	bool hasDefiningAttr() const;
696
697	/// Return this declaration's defining attribute if it has one.
698	const Attr *getDefiningAttr() const;
699
700	protected:
701	/// Specify that this declaration was marked as being private
702	/// to the module in which it was defined.
703	void setModulePrivate() {
704	// The module-private specifier has no effect on unowned declarations.
705	// FIXME: We should track this in some way for source fidelity.
706	if (getModuleOwnershipKind() == ModuleOwnershipKind::Unowned)
707	return;
708	setModuleOwnershipKind(ModuleOwnershipKind::ModulePrivate);
709	}
710
711	public:
712	/// Set the FromASTFile flag. This indicates that this declaration
713	/// was deserialized and not parsed from source code and enables
714	/// features such as module ownership information.
715	void setFromASTFile() {
716	FromASTFile = true;
717	}
718
719	/// Set the owning module ID. This may only be called for
720	/// deserialized Decls.
721	void setOwningModuleID(unsigned ID);
722
723	public:
724	/// Determine the availability of the given declaration.
725	///
726	/// This routine will determine the most restrictive availability of
727	/// the given declaration (e.g., preferring 'unavailable' to
728	/// 'deprecated').
729	///
730	/// \param Message If non-NULL and the result is not \c
731	/// AR_Available, will be set to a (possibly empty) message
732	/// describing why the declaration has not been introduced, is
733	/// deprecated, or is unavailable.
734	///
735	/// \param EnclosingVersion The version to compare with. If empty, assume the
736	/// deployment target version.
737	///
738	/// \param RealizedPlatform If non-NULL and the availability result is found
739	/// in an available attribute it will set to the platform which is written in
740	/// the available attribute.
741	AvailabilityResult
742	getAvailability(std::string *Message = nullptr,
743	VersionTuple EnclosingVersion = VersionTuple(),
744	StringRef *RealizedPlatform = nullptr) const;
745
746	/// Retrieve the version of the target platform in which this
747	/// declaration was introduced.
748	///
749	/// \returns An empty version tuple if this declaration has no 'introduced'
750	/// availability attributes, or the version tuple that's specified in the
751	/// attribute otherwise.
752	VersionTuple getVersionIntroduced() const;
753
754	/// Determine whether this declaration is marked 'deprecated'.
755	///
756	/// \param Message If non-NULL and the declaration is deprecated,
757	/// this will be set to the message describing why the declaration
758	/// was deprecated (which may be empty).
759	bool isDeprecated(std::string *Message = nullptr) const {
760	return getAvailability(Message) == AR_Deprecated;
761	}
762
763	/// Determine whether this declaration is marked 'unavailable'.
764	///
765	/// \param Message If non-NULL and the declaration is unavailable,
766	/// this will be set to the message describing why the declaration
767	/// was made unavailable (which may be empty).
768	bool isUnavailable(std::string *Message = nullptr) const {
769	return getAvailability(Message) == AR_Unavailable;
770	}
771
772	/// Determine whether this is a weak-imported symbol.
773	///
774	/// Weak-imported symbols are typically marked with the
775	/// 'weak_import' attribute, but may also be marked with an
776	/// 'availability' attribute where we're targing a platform prior to
777	/// the introduction of this feature.
778	bool isWeakImported() const;
779
780	/// Determines whether this symbol can be weak-imported,
781	/// e.g., whether it would be well-formed to add the weak_import
782	/// attribute.
783	///
784	/// \param IsDefinition Set to \c true to indicate that this
785	/// declaration cannot be weak-imported because it has a definition.
786	bool canBeWeakImported(bool &IsDefinition) const;
787
788	/// Determine whether this declaration came from an AST file (such as
789	/// a precompiled header or module) rather than having been parsed.
790	bool isFromASTFile() const { return FromASTFile; }
791
792	/// Retrieve the global declaration ID associated with this
793	/// declaration, which specifies where this Decl was loaded from.
794	GlobalDeclID getGlobalID() const;
795
796	/// Retrieve the global ID of the module that owns this particular
797	/// declaration.
798	unsigned getOwningModuleID() const;
799
800	private:
801	Module *getOwningModuleSlow() const;
802
803	protected:
804	bool hasLocalOwningModuleStorage() const;
805
806	public:
807	/// Get the imported owning module, if this decl is from an imported
808	/// (non-local) module.
809	Module *getImportedOwningModule() const {
810	if (!isFromASTFile() || !hasOwningModule())
811	return nullptr;
812
813	return getOwningModuleSlow();
814	}
815
816	/// Get the local owning module, if known. Returns nullptr if owner is
817	/// not yet known or declaration is not from a module.
818	Module *getLocalOwningModule() const {
819	if (isFromASTFile() || !hasOwningModule())
820	return nullptr;
821
822	assert(hasLocalOwningModuleStorage() &&
823	"owned local decl but no local module storage");
824	return reinterpret_cast<Module *const *>(this)[-1];
825	}
826	void setLocalOwningModule(Module *M) {
827	assert(!isFromASTFile() && hasOwningModule() &&
828	hasLocalOwningModuleStorage() &&
829	"should not have a cached owning module");
830	reinterpret_cast<Module **>(this)[-1] = M;
831	}
832
833	/// Is this declaration owned by some module?
834	bool hasOwningModule() const {
835	return getModuleOwnershipKind() != ModuleOwnershipKind::Unowned;
836	}
837
838	/// Get the module that owns this declaration (for visibility purposes).
839	Module *getOwningModule() const {
840	return isFromASTFile() ? getImportedOwningModule() : getLocalOwningModule();
841	}
842
843	/// Get the top level owning named module that owns this declaration if any.
844	/// \returns nullptr if the declaration is not owned by a named module.
845	Module *getTopLevelOwningNamedModule() const;
846
847	/// Get the module that owns this declaration for linkage purposes.
848	/// There only ever is such a standard C++ module.
849	Module *getOwningModuleForLinkage() const;
850
851	/// Determine whether this declaration is definitely visible to name lookup,
852	/// independent of whether the owning module is visible.
853	/// Note: The declaration may be visible even if this returns \c false if the
854	/// owning module is visible within the query context. This is a low-level
855	/// helper function; most code should be calling Sema::isVisible() instead.
856	bool isUnconditionallyVisible() const {
857	return (int)getModuleOwnershipKind() <= (int)ModuleOwnershipKind::Visible;
858	}
859
860	bool isReachable() const {
861	return (int)getModuleOwnershipKind() <=
862	(int)ModuleOwnershipKind::ReachableWhenImported;
863	}
864
865	/// Set that this declaration is globally visible, even if it came from a
866	/// module that is not visible.
867	void setVisibleDespiteOwningModule() {
868	if (!isUnconditionallyVisible())
869	setModuleOwnershipKind(ModuleOwnershipKind::Visible);
870	}
871
872	/// Get the kind of module ownership for this declaration.
873	ModuleOwnershipKind getModuleOwnershipKind() const {
874	return NextInContextAndBits.getInt();
875	}
876
877	/// Set whether this declaration is hidden from name lookup.
878	void setModuleOwnershipKind(ModuleOwnershipKind MOK) {
879	assert(!(getModuleOwnershipKind() == ModuleOwnershipKind::Unowned &&
880	MOK != ModuleOwnershipKind::Unowned && !isFromASTFile() &&
881	!hasLocalOwningModuleStorage()) &&
882	"no storage available for owning module for this declaration");
883	NextInContextAndBits.setInt(MOK);
884	}
885
886	unsigned getIdentifierNamespace() const {
887	return IdentifierNamespace;
888	}
889
890	bool isInIdentifierNamespace(unsigned NS) const {
891	return getIdentifierNamespace() & NS;
892	}
893
894	static unsigned getIdentifierNamespaceForKind(Kind DK);
895
896	bool hasTagIdentifierNamespace() const {
897	return isTagIdentifierNamespace(NS: getIdentifierNamespace());
898	}
899
900	static bool isTagIdentifierNamespace(unsigned NS) {
901	// TagDecls have Tag and Type set and may also have TagFriend.
902	return (NS & ~IDNS_TagFriend) == (IDNS_Tag | IDNS_Type);
903	}
904
905	/// getLexicalDeclContext - The declaration context where this Decl was
906	/// lexically declared (LexicalDC). May be different from
907	/// getDeclContext() (SemanticDC).
908	/// e.g.:
909	///
910	/// namespace A {
911	/// void f(); // SemanticDC == LexicalDC == 'namespace A'
912	/// }
913	/// void A::f(); // SemanticDC == namespace 'A'
914	/// // LexicalDC == global namespace
915	DeclContext *getLexicalDeclContext() {
916	if (isInSemaDC())
917	return getSemanticDC();
918	return getMultipleDC()->LexicalDC;
919	}
920	const DeclContext *getLexicalDeclContext() const {
921	return const_cast<Decl*>(this)->getLexicalDeclContext();
922	}
923
924	/// Determine whether this declaration is declared out of line (outside its
925	/// semantic context).
926	virtual bool isOutOfLine() const;
927
928	/// setDeclContext - Set both the semantic and lexical DeclContext
929	/// to DC.
930	void setDeclContext(DeclContext *DC);
931
932	void setLexicalDeclContext(DeclContext *DC);
933
934	/// Determine whether this declaration is a templated entity (whether it is
935	// within the scope of a template parameter).
936	bool isTemplated() const;
937
938	/// Determine the number of levels of template parameter surrounding this
939	/// declaration.
940	unsigned getTemplateDepth() const;
941
942	/// isDefinedOutsideFunctionOrMethod - This predicate returns true if this
943	/// scoped decl is defined outside the current function or method. This is
944	/// roughly global variables and functions, but also handles enums (which
945	/// could be defined inside or outside a function etc).
946	bool isDefinedOutsideFunctionOrMethod() const {
947	return getParentFunctionOrMethod() == nullptr;
948	}
949
950	/// Determine whether a substitution into this declaration would occur as
951	/// part of a substitution into a dependent local scope. Such a substitution
952	/// transitively substitutes into all constructs nested within this
953	/// declaration.
954	///
955	/// This recognizes non-defining declarations as well as members of local
956	/// classes and lambdas:
957	/// \code
958	/// template<typename T> void foo() { void bar(); }
959	/// template<typename T> void foo2() { class ABC { void bar(); }; }
960	/// template<typename T> inline int x = [](){ return 0; }();
961	/// \endcode
962	bool isInLocalScopeForInstantiation() const;
963
964	/// If this decl is defined inside a function/method/block it returns
965	/// the corresponding DeclContext, otherwise it returns null.
966	const DeclContext *
967	getParentFunctionOrMethod(bool LexicalParent = false) const;
968	DeclContext *getParentFunctionOrMethod(bool LexicalParent = false) {
969	return const_cast<DeclContext *>(
970	const_cast<const Decl *>(this)->getParentFunctionOrMethod(
971	LexicalParent));
972	}
973
974	/// Retrieves the "canonical" declaration of the given declaration.
975	virtual Decl *getCanonicalDecl() { return this; }
976	const Decl *getCanonicalDecl() const {
977	return const_cast<Decl*>(this)->getCanonicalDecl();
978	}
979
980	/// Whether this particular Decl is a canonical one.
981	bool isCanonicalDecl() const { return getCanonicalDecl() == this; }
982
983	protected:
984	/// Returns the next redeclaration or itself if this is the only decl.
985	///
986	/// Decl subclasses that can be redeclared should override this method so that
987	/// Decl::redecl_iterator can iterate over them.
988	virtual Decl *getNextRedeclarationImpl() { return this; }
989
990	/// Implementation of getPreviousDecl(), to be overridden by any
991	/// subclass that has a redeclaration chain.
992	virtual Decl *getPreviousDeclImpl() { return nullptr; }
993
994	/// Implementation of getMostRecentDecl(), to be overridden by any
995	/// subclass that has a redeclaration chain.
996	virtual Decl *getMostRecentDeclImpl() { return this; }
997
998	public:
999	/// Iterates through all the redeclarations of the same decl.
1000	class redecl_iterator {
1001	/// Current - The current declaration.
1002	Decl *Current = nullptr;
1003	Decl *Starter;
1004
1005	public:
1006	using value_type = Decl *;
1007	using reference = const value_type &;
1008	using pointer = const value_type *;
1009	using iterator_category = std::forward_iterator_tag;
1010	using difference_type = std::ptrdiff_t;
1011
1012	redecl_iterator() = default;
1013	explicit redecl_iterator(Decl *C) : Current(C), Starter(C) {}
1014
1015	reference operator*() const { return Current; }
1016	value_type operator->() const { return Current; }
1017
1018	redecl_iterator& operator++() {
1019	assert(Current && "Advancing while iterator has reached end");
1020	// Get either previous decl or latest decl.
1021	Decl *Next = Current->getNextRedeclarationImpl();
1022	assert(Next && "Should return next redeclaration or itself, never null!");
1023	Current = (Next != Starter) ? Next : nullptr;
1024	return *this;
1025	}
1026
1027	redecl_iterator operator++(int) {
1028	redecl_iterator tmp(*this);
1029	++(*this);
1030	return tmp;
1031	}
1032
1033	friend bool operator==(redecl_iterator x, redecl_iterator y) {
1034	return x.Current == y.Current;
1035	}
1036
1037	friend bool operator!=(redecl_iterator x, redecl_iterator y) {
1038	return x.Current != y.Current;
1039	}
1040	};
1041
1042	using redecl_range = llvm::iterator_range<redecl_iterator>;
1043
1044	/// Returns an iterator range for all the redeclarations of the same
1045	/// decl. It will iterate at least once (when this decl is the only one).
1046	redecl_range redecls() const {
1047	return redecl_range(redecls_begin(), redecls_end());
1048	}
1049
1050	redecl_iterator redecls_begin() const {
1051	return redecl_iterator(const_cast<Decl *>(this));
1052	}
1053
1054	redecl_iterator redecls_end() const { return redecl_iterator(); }
1055
1056	/// Retrieve the previous declaration that declares the same entity
1057	/// as this declaration, or NULL if there is no previous declaration.
1058	Decl *getPreviousDecl() { return getPreviousDeclImpl(); }
1059
1060	/// Retrieve the previous declaration that declares the same entity
1061	/// as this declaration, or NULL if there is no previous declaration.
1062	const Decl *getPreviousDecl() const {
1063	return const_cast<Decl *>(this)->getPreviousDeclImpl();
1064	}
1065
1066	/// True if this is the first declaration in its redeclaration chain.
1067	bool isFirstDecl() const {
1068	return getPreviousDecl() == nullptr;
1069	}
1070
1071	/// Retrieve the most recent declaration that declares the same entity
1072	/// as this declaration (which may be this declaration).
1073	Decl *getMostRecentDecl() { return getMostRecentDeclImpl(); }
1074
1075	/// Retrieve the most recent declaration that declares the same entity
1076	/// as this declaration (which may be this declaration).
1077	const Decl *getMostRecentDecl() const {
1078	return const_cast<Decl *>(this)->getMostRecentDeclImpl();
1079	}
1080
1081	/// getBody - If this Decl represents a declaration for a body of code,
1082	/// such as a function or method definition, this method returns the
1083	/// top-level Stmt* of that body. Otherwise this method returns null.
1084	virtual Stmt* getBody() const { return nullptr; }
1085
1086	/// Returns true if this \c Decl represents a declaration for a body of
1087	/// code, such as a function or method definition.
1088	/// Note that \c hasBody can also return true if any redeclaration of this
1089	/// \c Decl represents a declaration for a body of code.
1090	virtual bool hasBody() const { return getBody() != nullptr; }
1091
1092	/// getBodyRBrace - Gets the right brace of the body, if a body exists.
1093	/// This works whether the body is a CompoundStmt or a CXXTryStmt.
1094	SourceLocation getBodyRBrace() const;
1095
1096	// global temp stats (until we have a per-module visitor)
1097	static void add(Kind k);
1098	static void EnableStatistics();
1099	static void PrintStats();
1100
1101	/// isTemplateParameter - Determines whether this declaration is a
1102	/// template parameter.
1103	bool isTemplateParameter() const;
1104
1105	/// isTemplateParameter - Determines whether this declaration is a
1106	/// template parameter pack.
1107	bool isTemplateParameterPack() const;
1108
1109	/// Whether this declaration is a parameter pack.
1110	bool isParameterPack() const;
1111
1112	/// returns true if this declaration is a template
1113	bool isTemplateDecl() const;
1114
1115	/// Whether this declaration is a function or function template.
1116	bool isFunctionOrFunctionTemplate() const {
1117	return (DeclKind >= Decl::firstFunction &&
1118	DeclKind <= Decl::lastFunction) ||
1119	DeclKind == FunctionTemplate;
1120	}
1121
1122	/// If this is a declaration that describes some template, this
1123	/// method returns that template declaration.
1124	///
1125	/// Note that this returns nullptr for partial specializations, because they
1126	/// are not modeled as TemplateDecls. Use getDescribedTemplateParams to handle
1127	/// those cases.
1128	TemplateDecl *getDescribedTemplate() const;
1129
1130	/// If this is a declaration that describes some template or partial
1131	/// specialization, this returns the corresponding template parameter list.
1132	const TemplateParameterList *getDescribedTemplateParams() const;
1133
1134	/// Returns the function itself, or the templated function if this is a
1135	/// function template.
1136	FunctionDecl *getAsFunction() LLVM_READONLY;
1137
1138	const FunctionDecl *getAsFunction() const {
1139	return const_cast<Decl *>(this)->getAsFunction();
1140	}
1141
1142	/// Changes the namespace of this declaration to reflect that it's
1143	/// a function-local extern declaration.
1144	///
1145	/// These declarations appear in the lexical context of the extern
1146	/// declaration, but in the semantic context of the enclosing namespace
1147	/// scope.
1148	void setLocalExternDecl() {
1149	Decl *Prev = getPreviousDecl();
1150	IdentifierNamespace &= ~IDNS_Ordinary;
1151
1152	// It's OK for the declaration to still have the "invisible friend" flag or
1153	// the "conflicts with tag declarations in this scope" flag for the outer
1154	// scope.
1155	assert((IdentifierNamespace & ~(IDNS_OrdinaryFriend | IDNS_Tag)) == 0 &&
1156	"namespace is not ordinary");
1157
1158	IdentifierNamespace |= IDNS_LocalExtern;
1159	if (Prev && Prev->getIdentifierNamespace() & IDNS_Ordinary)
1160	IdentifierNamespace |= IDNS_Ordinary;
1161	}
1162
1163	/// Determine whether this is a block-scope declaration with linkage.
1164	/// This will either be a local variable declaration declared 'extern', or a
1165	/// local function declaration.
1166	bool isLocalExternDecl() const {
1167	return IdentifierNamespace & IDNS_LocalExtern;
1168	}
1169
1170	/// Changes the namespace of this declaration to reflect that it's
1171	/// the object of a friend declaration.
1172	///
1173	/// These declarations appear in the lexical context of the friending
1174	/// class, but in the semantic context of the actual entity. This property
1175	/// applies only to a specific decl object; other redeclarations of the
1176	/// same entity may not (and probably don't) share this property.
1177	void setObjectOfFriendDecl(bool PerformFriendInjection = false) {
1178	unsigned OldNS = IdentifierNamespace;
1179	assert((OldNS & (IDNS_Tag | IDNS_Ordinary |
1180	IDNS_TagFriend | IDNS_OrdinaryFriend |
1181	IDNS_LocalExtern | IDNS_NonMemberOperator)) &&
1182	"namespace includes neither ordinary nor tag");
1183	assert(!(OldNS & ~(IDNS_Tag | IDNS_Ordinary | IDNS_Type |
1184	IDNS_TagFriend | IDNS_OrdinaryFriend |
1185	IDNS_LocalExtern | IDNS_NonMemberOperator)) &&
1186	"namespace includes other than ordinary or tag");
1187
1188	Decl *Prev = getPreviousDecl();
1189	IdentifierNamespace &= ~(IDNS_Ordinary | IDNS_Tag | IDNS_Type);
1190
1191	if (OldNS & (IDNS_Tag | IDNS_TagFriend)) {
1192	IdentifierNamespace |= IDNS_TagFriend;
1193	if (PerformFriendInjection ||
1194	(Prev && Prev->getIdentifierNamespace() & IDNS_Tag))
1195	IdentifierNamespace |= IDNS_Tag | IDNS_Type;
1196	}
1197
1198	if (OldNS & (IDNS_Ordinary | IDNS_OrdinaryFriend |
1199	IDNS_LocalExtern | IDNS_NonMemberOperator)) {
1200	IdentifierNamespace |= IDNS_OrdinaryFriend;
1201	if (PerformFriendInjection ||
1202	(Prev && Prev->getIdentifierNamespace() & IDNS_Ordinary))
1203	IdentifierNamespace |= IDNS_Ordinary;
1204	}
1205	}
1206
1207	/// Clears the namespace of this declaration.
1208	///
1209	/// This is useful if we want this declaration to be available for
1210	/// redeclaration lookup but otherwise hidden for ordinary name lookups.
1211	void clearIdentifierNamespace() { IdentifierNamespace = 0; }
1212
1213	enum FriendObjectKind {
1214	FOK_None, ///< Not a friend object.
1215	FOK_Declared, ///< A friend of a previously-declared entity.
1216	FOK_Undeclared ///< A friend of a previously-undeclared entity.
1217	};
1218
1219	/// Determines whether this declaration is the object of a
1220	/// friend declaration and, if so, what kind.
1221	///
1222	/// There is currently no direct way to find the associated FriendDecl.
1223	FriendObjectKind getFriendObjectKind() const {
1224	unsigned mask =
1225	(IdentifierNamespace & (IDNS_TagFriend | IDNS_OrdinaryFriend));
1226	if (!mask) return FOK_None;
1227	return (IdentifierNamespace & (IDNS_Tag | IDNS_Ordinary) ? FOK_Declared
1228	: FOK_Undeclared);
1229	}
1230
1231	/// Specifies that this declaration is a C++ overloaded non-member.
1232	void setNonMemberOperator() {
1233	assert(getKind() == Function || getKind() == FunctionTemplate);
1234	assert((IdentifierNamespace & IDNS_Ordinary) &&
1235	"visible non-member operators should be in ordinary namespace");
1236	IdentifierNamespace |= IDNS_NonMemberOperator;
1237	}
1238
1239	static bool classofKind(Kind K) { return true; }
1240	static DeclContext *castToDeclContext(const Decl *);
1241	static Decl *castFromDeclContext(const DeclContext *);
1242
1243	void print(raw_ostream &Out, unsigned Indentation = 0,
1244	bool PrintInstantiation = false) const;
1245	void print(raw_ostream &Out, const PrintingPolicy &Policy,
1246	unsigned Indentation = 0, bool PrintInstantiation = false) const;
1247	static void printGroup(Decl** Begin, unsigned NumDecls,
1248	raw_ostream &Out, const PrintingPolicy &Policy,
1249	unsigned Indentation = 0);
1250
1251	// Debuggers don't usually respect default arguments.
1252	void dump() const;
1253
1254	// Same as dump(), but forces color printing.
1255	void dumpColor() const;
1256
1257	void dump(raw_ostream &Out, bool Deserialize = false,
1258	ASTDumpOutputFormat OutputFormat = ADOF_Default) const;
1259
1260	/// \return Unique reproducible object identifier
1261	int64_t getID() const;
1262
1263	/// Looks through the Decl's underlying type to extract a FunctionType
1264	/// when possible. This includes direct FunctionDecls, along with various
1265	/// function types and typedefs. This includes function pointers/references,
1266	/// member function pointers, and optionally if \p BlocksToo is set
1267	/// Objective-C block pointers. Returns nullptr if the type underlying the
1268	/// Decl does not have a FunctionType.
1269	const FunctionType *getFunctionType(bool BlocksToo = true) const;
1270
1271	// Looks through the Decl's underlying type to determine if it's a
1272	// function pointer type.
1273	bool isFunctionPointerType() const;
1274
1275	private:
1276	void setAttrsImpl(const AttrVec& Attrs, ASTContext &Ctx);
1277	void setDeclContextsImpl(DeclContext *SemaDC, DeclContext *LexicalDC,
1278	ASTContext &Ctx);
1279
1280	protected:
1281	ASTMutationListener *getASTMutationListener() const;
1282	};
1283
1284	/// Determine whether two declarations declare the same entity.
1285	inline bool declaresSameEntity(const Decl *D1, const Decl *D2) {
1286	if (!D1 || !D2)
1287	return false;
1288
1289	if (D1 == D2)
1290	return true;
1291
1292	return D1->getCanonicalDecl() == D2->getCanonicalDecl();
1293	}
1294
1295	/// PrettyStackTraceDecl - If a crash occurs, indicate that it happened when
1296	/// doing something to a specific decl.
1297	class PrettyStackTraceDecl : public llvm::PrettyStackTraceEntry {
1298	const Decl *TheDecl;
1299	SourceLocation Loc;
1300	SourceManager &SM;
1301	const char *Message;
1302
1303	public:
1304	PrettyStackTraceDecl(const Decl *theDecl, SourceLocation L,
1305	SourceManager &sm, const char *Msg)
1306	: TheDecl(theDecl), Loc(L), SM(sm), Message(Msg) {}
1307
1308	void print(raw_ostream &OS) const override;
1309	};
1310	} // namespace clang
1311
1312	// Required to determine the layout of the PointerUnion<NamedDecl*> before
1313	// seeing the NamedDecl definition being first used in DeclListNode::operator*.
1314	namespace llvm {
1315	template <> struct PointerLikeTypeTraits<::clang::NamedDecl *> {
1316	static inline void *getAsVoidPointer(::clang::NamedDecl *P) { return P; }
1317	static inline ::clang::NamedDecl *getFromVoidPointer(void *P) {
1318	return static_cast<::clang::NamedDecl *>(P);
1319	}
1320	static constexpr int NumLowBitsAvailable = 3;
1321	};
1322	}
1323
1324	namespace clang {
1325	/// A list storing NamedDecls in the lookup tables.
1326	class DeclListNode {
1327	friend class ASTContext; // allocate, deallocate nodes.
1328	friend class StoredDeclsList;
1329	public:
1330	using Decls = llvm::PointerUnion<NamedDecl*, DeclListNode*>;
1331	class iterator {
1332	friend class DeclContextLookupResult;
1333	friend class StoredDeclsList;
1334
1335	Decls Ptr;
1336	iterator(Decls Node) : Ptr(Node) { }
1337	public:
1338	using difference_type = ptrdiff_t;
1339	using value_type = NamedDecl*;
1340	using pointer = void;
1341	using reference = value_type;
1342	using iterator_category = std::forward_iterator_tag;
1343
1344	iterator() = default;
1345
1346	reference operator*() const {
1347	assert(Ptr && "dereferencing end() iterator");
1348	if (DeclListNode *CurNode = dyn_cast<DeclListNode *>(Val: Ptr))
1349	return CurNode->D;
1350	return cast<NamedDecl *>(Val: Ptr);
1351	}
1352	void operator->() const { } // Unsupported.
1353	bool operator==(const iterator &X) const { return Ptr == X.Ptr; }
1354	bool operator!=(const iterator &X) const { return Ptr != X.Ptr; }
1355	inline iterator &operator++() { // ++It
1356	assert(!Ptr.isNull() && "Advancing empty iterator");
1357
1358	if (DeclListNode *CurNode = dyn_cast<DeclListNode *>(Val&: Ptr))
1359	Ptr = CurNode->Rest;
1360	else
1361	Ptr = nullptr;
1362	return *this;
1363	}
1364	iterator operator++(int) { // It++
1365	iterator temp = *this;
1366	++(*this);
1367	return temp;
1368	}
1369	// Enables the pattern for (iterator I =..., E = I.end(); I != E; ++I)
1370	iterator end() { return iterator(); }
1371	};
1372	private:
1373	NamedDecl *D = nullptr;
1374	Decls Rest = nullptr;
1375	DeclListNode(NamedDecl *ND) : D(ND) {}
1376	};
1377
1378	/// The results of name lookup within a DeclContext.
1379	class DeclContextLookupResult {
1380	using Decls = DeclListNode::Decls;
1381
1382	/// When in collection form, this is what the Data pointer points to.
1383	Decls Result;
1384
1385	public:
1386	DeclContextLookupResult() = default;
1387	DeclContextLookupResult(Decls Result) : Result(Result) {}
1388
1389	using iterator = DeclListNode::iterator;
1390	using const_iterator = iterator;
1391	using reference = iterator::reference;
1392
1393	iterator begin() { return iterator(Result); }
1394	iterator end() { return iterator(); }
1395	const_iterator begin() const {
1396	return const_cast<DeclContextLookupResult*>(this)->begin();
1397	}
1398	const_iterator end() const { return iterator(); }
1399
1400	bool empty() const { return Result.isNull(); }
1401	bool isSingleResult() const { return isa_and_present<NamedDecl *>(Val: Result); }
1402	reference front() const { return *begin(); }
1403
1404	// Find the first declaration of the given type in the list. Note that this
1405	// is not in general the earliest-declared declaration, and should only be
1406	// used when it's not possible for there to be more than one match or where
1407	// it doesn't matter which one is found.
1408	template<class T> T *find_first() const {
1409	for (auto *D : *this)
1410	if (T *Decl = dyn_cast<T>(D))
1411	return Decl;
1412
1413	return nullptr;
1414	}
1415	};
1416
1417	/// Only used by CXXDeductionGuideDecl.
1418	enum class DeductionCandidate : unsigned char {
1419	Normal,
1420	Copy,
1421	Aggregate,
1422	};
1423
1424	enum class RecordArgPassingKind;
1425	enum class OMPDeclareReductionInitKind;
1426	enum class ObjCImplementationControl;
1427	enum class LinkageSpecLanguageIDs;
1428
1429	/// DeclContext - This is used only as base class of specific decl types that
1430	/// can act as declaration contexts. These decls are (only the top classes
1431	/// that directly derive from DeclContext are mentioned, not their subclasses):
1432	///
1433	/// TranslationUnitDecl
1434	/// ExternCContext
1435	/// NamespaceDecl
1436	/// TagDecl
1437	/// OMPDeclareReductionDecl
1438	/// OMPDeclareMapperDecl
1439	/// FunctionDecl
1440	/// ObjCMethodDecl
1441	/// ObjCContainerDecl
1442	/// LinkageSpecDecl
1443	/// ExportDecl
1444	/// BlockDecl
1445	/// CapturedDecl
1446	class DeclContext {
1447	/// For makeDeclVisibleInContextImpl
1448	friend class ASTDeclReader;
1449	/// For checking the new bits in the Serialization part.
1450	friend class ASTDeclWriter;
1451	/// For reconcileExternalVisibleStorage, CreateStoredDeclsMap,
1452	/// hasNeedToReconcileExternalVisibleStorage
1453	friend class ExternalASTSource;
1454	/// For CreateStoredDeclsMap
1455	friend class DependentDiagnostic;
1456	/// For hasNeedToReconcileExternalVisibleStorage,
1457	/// hasLazyLocalLexicalLookups, hasLazyExternalLexicalLookups
1458	friend class ASTWriter;
1459
1460	protected:
1461	enum { NumOdrHashBits = 25 };
1462
1463	// We use uint64_t in the bit-fields below since some bit-fields
1464	// cross the unsigned boundary and this breaks the packing.
1465
1466	/// Stores the bits used by DeclContext.
1467	/// If modified NumDeclContextBit, the ctor of DeclContext and the accessor
1468	/// methods in DeclContext should be updated appropriately.
1469	class DeclContextBitfields {
1470	friend class DeclContext;
1471	/// DeclKind - This indicates which class this is.
1472	LLVM_PREFERRED_TYPE(Decl::Kind)
1473	uint64_t DeclKind : 7;
1474
1475	/// Whether this declaration context also has some external
1476	/// storage that contains additional declarations that are lexically
1477	/// part of this context.
1478	LLVM_PREFERRED_TYPE(bool)
1479	mutable uint64_t ExternalLexicalStorage : 1;
1480
1481	/// Whether this declaration context also has some external
1482	/// storage that contains additional declarations that are visible
1483	/// in this context.
1484	LLVM_PREFERRED_TYPE(bool)
1485	mutable uint64_t ExternalVisibleStorage : 1;
1486
1487	/// Whether this declaration context has had externally visible
1488	/// storage added since the last lookup. In this case, \c LookupPtr's
1489	/// invariant may not hold and needs to be fixed before we perform
1490	/// another lookup.
1491	LLVM_PREFERRED_TYPE(bool)
1492	mutable uint64_t NeedToReconcileExternalVisibleStorage : 1;
1493
1494	/// If \c true, this context may have local lexical declarations
1495	/// that are missing from the lookup table.
1496	LLVM_PREFERRED_TYPE(bool)
1497	mutable uint64_t HasLazyLocalLexicalLookups : 1;
1498
1499	/// If \c true, the external source may have lexical declarations
1500	/// that are missing from the lookup table.
1501	LLVM_PREFERRED_TYPE(bool)
1502	mutable uint64_t HasLazyExternalLexicalLookups : 1;
1503
1504	/// If \c true, lookups should only return identifier from
1505	/// DeclContext scope (for example TranslationUnit). Used in
1506	/// LookupQualifiedName()
1507	LLVM_PREFERRED_TYPE(bool)
1508	mutable uint64_t UseQualifiedLookup : 1;
1509	};
1510
1511	/// Number of bits in DeclContextBitfields.
1512	enum { NumDeclContextBits = 13 };
1513
1514	/// Stores the bits used by NamespaceDecl.
1515	/// If modified NumNamespaceDeclBits and the accessor
1516	/// methods in NamespaceDecl should be updated appropriately.
1517	class NamespaceDeclBitfields {
1518	friend class NamespaceDecl;
1519	/// For the bits in DeclContextBitfields
1520	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1521	uint64_t : NumDeclContextBits;
1522
1523	/// True if this is an inline namespace.
1524	LLVM_PREFERRED_TYPE(bool)
1525	uint64_t IsInline : 1;
1526
1527	/// True if this is a nested-namespace-definition.
1528	LLVM_PREFERRED_TYPE(bool)
1529	uint64_t IsNested : 1;
1530	};
1531
1532	/// Number of inherited and non-inherited bits in NamespaceDeclBitfields.
1533	enum { NumNamespaceDeclBits = NumDeclContextBits + 2 };
1534
1535	/// Stores the bits used by TagDecl.
1536	/// If modified NumTagDeclBits and the accessor
1537	/// methods in TagDecl should be updated appropriately.
1538	class TagDeclBitfields {
1539	friend class TagDecl;
1540	/// For the bits in DeclContextBitfields
1541	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1542	uint64_t : NumDeclContextBits;
1543
1544	/// The TagKind enum.
1545	LLVM_PREFERRED_TYPE(TagTypeKind)
1546	uint64_t TagDeclKind : 3;
1547
1548	/// True if this is a definition ("struct foo {};"), false if it is a
1549	/// declaration ("struct foo;"). It is not considered a definition
1550	/// until the definition has been fully processed.
1551	LLVM_PREFERRED_TYPE(bool)
1552	uint64_t IsCompleteDefinition : 1;
1553
1554	/// True if this is currently being defined.
1555	LLVM_PREFERRED_TYPE(bool)
1556	uint64_t IsBeingDefined : 1;
1557
1558	/// True if this tag declaration is "embedded" (i.e., defined or declared
1559	/// for the very first time) in the syntax of a declarator.
1560	LLVM_PREFERRED_TYPE(bool)
1561	uint64_t IsEmbeddedInDeclarator : 1;
1562
1563	/// True if this tag is free standing, e.g. "struct foo;".
1564	LLVM_PREFERRED_TYPE(bool)
1565	uint64_t IsFreeStanding : 1;
1566
1567	/// Indicates whether it is possible for declarations of this kind
1568	/// to have an out-of-date definition.
1569	///
1570	/// This option is only enabled when modules are enabled.
1571	LLVM_PREFERRED_TYPE(bool)
1572	uint64_t MayHaveOutOfDateDef : 1;
1573
1574	/// Has the full definition of this type been required by a use somewhere in
1575	/// the TU.
1576	LLVM_PREFERRED_TYPE(bool)
1577	uint64_t IsCompleteDefinitionRequired : 1;
1578
1579	/// Whether this tag is a definition which was demoted due to
1580	/// a module merge.
1581	LLVM_PREFERRED_TYPE(bool)
1582	uint64_t IsThisDeclarationADemotedDefinition : 1;
1583	};
1584
1585	/// Number of inherited and non-inherited bits in TagDeclBitfields.
1586	enum { NumTagDeclBits = NumDeclContextBits + 10 };
1587
1588	/// Stores the bits used by EnumDecl.
1589	/// If modified NumEnumDeclBit and the accessor
1590	/// methods in EnumDecl should be updated appropriately.
1591	class EnumDeclBitfields {
1592	friend class EnumDecl;
1593	/// For the bits in TagDeclBitfields.
1594	LLVM_PREFERRED_TYPE(TagDeclBitfields)
1595	uint64_t : NumTagDeclBits;
1596
1597	/// Width in bits required to store all the non-negative
1598	/// enumerators of this enum.
1599	uint64_t NumPositiveBits : 8;
1600
1601	/// Width in bits required to store all the negative
1602	/// enumerators of this enum.
1603	uint64_t NumNegativeBits : 8;
1604
1605	/// True if this tag declaration is a scoped enumeration. Only
1606	/// possible in C++11 mode.
1607	LLVM_PREFERRED_TYPE(bool)
1608	uint64_t IsScoped : 1;
1609
1610	/// If this tag declaration is a scoped enum,
1611	/// then this is true if the scoped enum was declared using the class
1612	/// tag, false if it was declared with the struct tag. No meaning is
1613	/// associated if this tag declaration is not a scoped enum.
1614	LLVM_PREFERRED_TYPE(bool)
1615	uint64_t IsScopedUsingClassTag : 1;
1616
1617	/// True if this is an enumeration with fixed underlying type. Only
1618	/// possible in C++11, Microsoft extensions, or Objective C mode.
1619	LLVM_PREFERRED_TYPE(bool)
1620	uint64_t IsFixed : 1;
1621
1622	/// True if a valid hash is stored in ODRHash.
1623	LLVM_PREFERRED_TYPE(bool)
1624	uint64_t HasODRHash : 1;
1625	};
1626
1627	/// Number of inherited and non-inherited bits in EnumDeclBitfields.
1628	enum { NumEnumDeclBits = NumTagDeclBits + 20 };
1629
1630	/// Stores the bits used by RecordDecl.
1631	/// If modified NumRecordDeclBits and the accessor
1632	/// methods in RecordDecl should be updated appropriately.
1633	class RecordDeclBitfields {
1634	friend class RecordDecl;
1635	/// For the bits in TagDeclBitfields.
1636	LLVM_PREFERRED_TYPE(TagDeclBitfields)
1637	uint64_t : NumTagDeclBits;
1638
1639	/// This is true if this struct ends with a flexible
1640	/// array member (e.g. int X[]) or if this union contains a struct that does.
1641	/// If so, this cannot be contained in arrays or other structs as a member.
1642	LLVM_PREFERRED_TYPE(bool)
1643	uint64_t HasFlexibleArrayMember : 1;
1644
1645	/// Whether this is the type of an anonymous struct or union.
1646	LLVM_PREFERRED_TYPE(bool)
1647	uint64_t AnonymousStructOrUnion : 1;
1648
1649	/// This is true if this struct has at least one member
1650	/// containing an Objective-C object pointer type.
1651	LLVM_PREFERRED_TYPE(bool)
1652	uint64_t HasObjectMember : 1;
1653
1654	/// This is true if struct has at least one member of
1655	/// 'volatile' type.
1656	LLVM_PREFERRED_TYPE(bool)
1657	uint64_t HasVolatileMember : 1;
1658
1659	/// Whether the field declarations of this record have been loaded
1660	/// from external storage. To avoid unnecessary deserialization of
1661	/// methods/nested types we allow deserialization of just the fields
1662	/// when needed.
1663	LLVM_PREFERRED_TYPE(bool)
1664	mutable uint64_t LoadedFieldsFromExternalStorage : 1;
1665
1666	/// Basic properties of non-trivial C structs.
1667	LLVM_PREFERRED_TYPE(bool)
1668	uint64_t NonTrivialToPrimitiveDefaultInitialize : 1;
1669	LLVM_PREFERRED_TYPE(bool)
1670	uint64_t NonTrivialToPrimitiveCopy : 1;
1671	LLVM_PREFERRED_TYPE(bool)
1672	uint64_t NonTrivialToPrimitiveDestroy : 1;
1673
1674	/// The following bits indicate whether this is or contains a C union that
1675	/// is non-trivial to default-initialize, destruct, or copy. These bits
1676	/// imply the associated basic non-triviality predicates declared above.
1677	LLVM_PREFERRED_TYPE(bool)
1678	uint64_t HasNonTrivialToPrimitiveDefaultInitializeCUnion : 1;
1679	LLVM_PREFERRED_TYPE(bool)
1680	uint64_t HasNonTrivialToPrimitiveDestructCUnion : 1;
1681	LLVM_PREFERRED_TYPE(bool)
1682	uint64_t HasNonTrivialToPrimitiveCopyCUnion : 1;
1683
1684	/// True if any field is marked as requiring explicit initialization with
1685	/// [[clang::require_explicit_initialization]].
1686	/// In C++, this is also set for types without a user-provided default
1687	/// constructor, and is propagated from any base classes and/or member
1688	/// variables whose types are aggregates.
1689	LLVM_PREFERRED_TYPE(bool)
1690	uint64_t HasUninitializedExplicitInitFields : 1;
1691
1692	/// Indicates whether this struct is destroyed in the callee.
1693	LLVM_PREFERRED_TYPE(bool)
1694	uint64_t ParamDestroyedInCallee : 1;
1695
1696	/// Represents the way this type is passed to a function.
1697	LLVM_PREFERRED_TYPE(RecordArgPassingKind)
1698	uint64_t ArgPassingRestrictions : 2;
1699
1700	/// Indicates whether this struct has had its field layout randomized.
1701	LLVM_PREFERRED_TYPE(bool)
1702	uint64_t IsRandomized : 1;
1703
1704	/// True if a valid hash is stored in ODRHash. This should shave off some
1705	/// extra storage and prevent CXXRecordDecl to store unused bits.
1706	uint64_t ODRHash : NumOdrHashBits;
1707	};
1708
1709	/// Number of inherited and non-inherited bits in RecordDeclBitfields.
1710	enum { NumRecordDeclBits = NumTagDeclBits + 41 };
1711
1712	/// Stores the bits used by OMPDeclareReductionDecl.
1713	/// If modified NumOMPDeclareReductionDeclBits and the accessor
1714	/// methods in OMPDeclareReductionDecl should be updated appropriately.
1715	class OMPDeclareReductionDeclBitfields {
1716	friend class OMPDeclareReductionDecl;
1717	/// For the bits in DeclContextBitfields
1718	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1719	uint64_t : NumDeclContextBits;
1720
1721	/// Kind of initializer,
1722	/// function call or omp_priv<init_expr> initialization.
1723	LLVM_PREFERRED_TYPE(OMPDeclareReductionInitKind)
1724	uint64_t InitializerKind : 2;
1725	};
1726
1727	/// Number of inherited and non-inherited bits in
1728	/// OMPDeclareReductionDeclBitfields.
1729	enum { NumOMPDeclareReductionDeclBits = NumDeclContextBits + 2 };
1730
1731	/// Stores the bits used by FunctionDecl.
1732	/// If modified NumFunctionDeclBits and the accessor
1733	/// methods in FunctionDecl and CXXDeductionGuideDecl
1734	/// (for DeductionCandidateKind) should be updated appropriately.
1735	class FunctionDeclBitfields {
1736	friend class FunctionDecl;
1737	/// For DeductionCandidateKind
1738	friend class CXXDeductionGuideDecl;
1739	/// For the bits in DeclContextBitfields.
1740	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1741	uint64_t : NumDeclContextBits;
1742
1743	LLVM_PREFERRED_TYPE(StorageClass)
1744	uint64_t SClass : 3;
1745	LLVM_PREFERRED_TYPE(bool)
1746	uint64_t IsInline : 1;
1747	LLVM_PREFERRED_TYPE(bool)
1748	uint64_t IsInlineSpecified : 1;
1749
1750	LLVM_PREFERRED_TYPE(bool)
1751	uint64_t IsVirtualAsWritten : 1;
1752	LLVM_PREFERRED_TYPE(bool)
1753	uint64_t IsPureVirtual : 1;
1754	LLVM_PREFERRED_TYPE(bool)
1755	uint64_t HasInheritedPrototype : 1;
1756	LLVM_PREFERRED_TYPE(bool)
1757	uint64_t HasWrittenPrototype : 1;
1758	LLVM_PREFERRED_TYPE(bool)
1759	uint64_t IsDeleted : 1;
1760	/// Used by CXXMethodDecl
1761	LLVM_PREFERRED_TYPE(bool)
1762	uint64_t IsTrivial : 1;
1763
1764	/// This flag indicates whether this function is trivial for the purpose of
1765	/// calls. This is meaningful only when this function is a copy/move
1766	/// constructor or a destructor.
1767	LLVM_PREFERRED_TYPE(bool)
1768	uint64_t IsTrivialForCall : 1;
1769
1770	LLVM_PREFERRED_TYPE(bool)
1771	uint64_t IsDefaulted : 1;
1772	LLVM_PREFERRED_TYPE(bool)
1773	uint64_t IsExplicitlyDefaulted : 1;
1774	LLVM_PREFERRED_TYPE(bool)
1775	uint64_t HasDefaultedOrDeletedInfo : 1;
1776
1777	/// For member functions of complete types, whether this is an ineligible
1778	/// special member function or an unselected destructor. See
1779	/// [class.mem.special].
1780	LLVM_PREFERRED_TYPE(bool)
1781	uint64_t IsIneligibleOrNotSelected : 1;
1782
1783	LLVM_PREFERRED_TYPE(bool)
1784	uint64_t HasImplicitReturnZero : 1;
1785	LLVM_PREFERRED_TYPE(bool)
1786	uint64_t IsLateTemplateParsed : 1;
1787	LLVM_PREFERRED_TYPE(bool)
1788	uint64_t IsInstantiatedFromMemberTemplate : 1;
1789
1790	/// Kind of contexpr specifier as defined by ConstexprSpecKind.
1791	LLVM_PREFERRED_TYPE(ConstexprSpecKind)
1792	uint64_t ConstexprKind : 2;
1793	LLVM_PREFERRED_TYPE(bool)
1794	uint64_t BodyContainsImmediateEscalatingExpression : 1;
1795
1796	LLVM_PREFERRED_TYPE(bool)
1797	uint64_t InstantiationIsPending : 1;
1798
1799	/// Indicates if the function uses __try.
1800	LLVM_PREFERRED_TYPE(bool)
1801	uint64_t UsesSEHTry : 1;
1802
1803	/// Indicates if the function was a definition
1804	/// but its body was skipped.
1805	LLVM_PREFERRED_TYPE(bool)
1806	uint64_t HasSkippedBody : 1;
1807
1808	/// Indicates if the function declaration will
1809	/// have a body, once we're done parsing it.
1810	LLVM_PREFERRED_TYPE(bool)
1811	uint64_t WillHaveBody : 1;
1812
1813	/// Indicates that this function is a multiversioned
1814	/// function using attribute 'target'.
1815	LLVM_PREFERRED_TYPE(bool)
1816	uint64_t IsMultiVersion : 1;
1817
1818	/// Only used by CXXDeductionGuideDecl. Indicates the kind
1819	/// of the Deduction Guide that is implicitly generated
1820	/// (used during overload resolution).
1821	LLVM_PREFERRED_TYPE(DeductionCandidate)
1822	uint64_t DeductionCandidateKind : 2;
1823
1824	/// Store the ODRHash after first calculation.
1825	LLVM_PREFERRED_TYPE(bool)
1826	uint64_t HasODRHash : 1;
1827
1828	/// Indicates if the function uses Floating Point Constrained Intrinsics
1829	LLVM_PREFERRED_TYPE(bool)
1830	uint64_t UsesFPIntrin : 1;
1831
1832	// Indicates this function is a constrained friend, where the constraint
1833	// refers to an enclosing template for hte purposes of [temp.friend]p9.
1834	LLVM_PREFERRED_TYPE(bool)
1835	uint64_t FriendConstraintRefersToEnclosingTemplate : 1;
1836	};
1837
1838	/// Number of inherited and non-inherited bits in FunctionDeclBitfields.
1839	enum { NumFunctionDeclBits = NumDeclContextBits + 32 };
1840
1841	/// Stores the bits used by CXXConstructorDecl. If modified
1842	/// NumCXXConstructorDeclBits and the accessor
1843	/// methods in CXXConstructorDecl should be updated appropriately.
1844	class CXXConstructorDeclBitfields {
1845	friend class CXXConstructorDecl;
1846	/// For the bits in FunctionDeclBitfields.
1847	LLVM_PREFERRED_TYPE(FunctionDeclBitfields)
1848	uint64_t : NumFunctionDeclBits;
1849
1850	/// 19 bits to fit in the remaining available space.
1851	/// Note that this makes CXXConstructorDeclBitfields take
1852	/// exactly 64 bits and thus the width of NumCtorInitializers
1853	/// will need to be shrunk if some bit is added to NumDeclContextBitfields,
1854	/// NumFunctionDeclBitfields or CXXConstructorDeclBitfields.
1855	uint64_t NumCtorInitializers : 16;
1856	LLVM_PREFERRED_TYPE(bool)
1857	uint64_t IsInheritingConstructor : 1;
1858
1859	/// Whether this constructor has a trail-allocated explicit specifier.
1860	LLVM_PREFERRED_TYPE(bool)
1861	uint64_t HasTrailingExplicitSpecifier : 1;
1862	/// If this constructor does't have a trail-allocated explicit specifier.
1863	/// Whether this constructor is explicit specified.
1864	LLVM_PREFERRED_TYPE(bool)
1865	uint64_t IsSimpleExplicit : 1;
1866	};
1867
1868	/// Number of inherited and non-inherited bits in CXXConstructorDeclBitfields.
1869	enum { NumCXXConstructorDeclBits = NumFunctionDeclBits + 19 };
1870
1871	/// Stores the bits used by ObjCMethodDecl.
1872	/// If modified NumObjCMethodDeclBits and the accessor
1873	/// methods in ObjCMethodDecl should be updated appropriately.
1874	class ObjCMethodDeclBitfields {
1875	friend class ObjCMethodDecl;
1876
1877	/// For the bits in DeclContextBitfields.
1878	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1879	uint64_t : NumDeclContextBits;
1880
1881	/// The conventional meaning of this method; an ObjCMethodFamily.
1882	/// This is not serialized; instead, it is computed on demand and
1883	/// cached.
1884	LLVM_PREFERRED_TYPE(ObjCMethodFamily)
1885	mutable uint64_t Family : ObjCMethodFamilyBitWidth;
1886
1887	/// instance (true) or class (false) method.
1888	LLVM_PREFERRED_TYPE(bool)
1889	uint64_t IsInstance : 1;
1890	LLVM_PREFERRED_TYPE(bool)
1891	uint64_t IsVariadic : 1;
1892
1893	/// True if this method is the getter or setter for an explicit property.
1894	LLVM_PREFERRED_TYPE(bool)
1895	uint64_t IsPropertyAccessor : 1;
1896
1897	/// True if this method is a synthesized property accessor stub.
1898	LLVM_PREFERRED_TYPE(bool)
1899	uint64_t IsSynthesizedAccessorStub : 1;
1900
1901	/// Method has a definition.
1902	LLVM_PREFERRED_TYPE(bool)
1903	uint64_t IsDefined : 1;
1904
1905	/// Method redeclaration in the same interface.
1906	LLVM_PREFERRED_TYPE(bool)
1907	uint64_t IsRedeclaration : 1;
1908
1909	/// Is redeclared in the same interface.
1910	LLVM_PREFERRED_TYPE(bool)
1911	mutable uint64_t HasRedeclaration : 1;
1912
1913	/// \@required/\@optional
1914	LLVM_PREFERRED_TYPE(ObjCImplementationControl)
1915	uint64_t DeclImplementation : 2;
1916
1917	/// in, inout, etc.
1918	LLVM_PREFERRED_TYPE(Decl::ObjCDeclQualifier)
1919	uint64_t objcDeclQualifier : 7;
1920
1921	/// Indicates whether this method has a related result type.
1922	LLVM_PREFERRED_TYPE(bool)
1923	uint64_t RelatedResultType : 1;
1924
1925	/// Whether the locations of the selector identifiers are in a
1926	/// "standard" position, a enum SelectorLocationsKind.
1927	LLVM_PREFERRED_TYPE(SelectorLocationsKind)
1928	uint64_t SelLocsKind : 2;
1929
1930	/// Whether this method overrides any other in the class hierarchy.
1931	///
1932	/// A method is said to override any method in the class's
1933	/// base classes, its protocols, or its categories' protocols, that has
1934	/// the same selector and is of the same kind (class or instance).
1935	/// A method in an implementation is not considered as overriding the same
1936	/// method in the interface or its categories.
1937	LLVM_PREFERRED_TYPE(bool)
1938	uint64_t IsOverriding : 1;
1939
1940	/// Indicates if the method was a definition but its body was skipped.
1941	LLVM_PREFERRED_TYPE(bool)
1942	uint64_t HasSkippedBody : 1;
1943	};
1944
1945	/// Number of inherited and non-inherited bits in ObjCMethodDeclBitfields.
1946	enum { NumObjCMethodDeclBits = NumDeclContextBits + 24 };
1947
1948	/// Stores the bits used by ObjCContainerDecl.
1949	/// If modified NumObjCContainerDeclBits and the accessor
1950	/// methods in ObjCContainerDecl should be updated appropriately.
1951	class ObjCContainerDeclBitfields {
1952	friend class ObjCContainerDecl;
1953	/// For the bits in DeclContextBitfields
1954	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1955	uint32_t : NumDeclContextBits;
1956
1957	// Not a bitfield but this saves space.
1958	// Note that ObjCContainerDeclBitfields is full.
1959	SourceLocation AtStart;
1960	};
1961
1962	/// Number of inherited and non-inherited bits in ObjCContainerDeclBitfields.
1963	/// Note that here we rely on the fact that SourceLocation is 32 bits
1964	/// wide. We check this with the static_assert in the ctor of DeclContext.
1965	enum { NumObjCContainerDeclBits = 64 };
1966
1967	/// Stores the bits used by LinkageSpecDecl.
1968	/// If modified NumLinkageSpecDeclBits and the accessor
1969	/// methods in LinkageSpecDecl should be updated appropriately.
1970	class LinkageSpecDeclBitfields {
1971	friend class LinkageSpecDecl;
1972	/// For the bits in DeclContextBitfields.
1973	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1974	uint64_t : NumDeclContextBits;
1975
1976	/// The language for this linkage specification.
1977	LLVM_PREFERRED_TYPE(LinkageSpecLanguageIDs)
1978	uint64_t Language : 3;
1979
1980	/// True if this linkage spec has braces.
1981	/// This is needed so that hasBraces() returns the correct result while the
1982	/// linkage spec body is being parsed. Once RBraceLoc has been set this is
1983	/// not used, so it doesn't need to be serialized.
1984	LLVM_PREFERRED_TYPE(bool)
1985	uint64_t HasBraces : 1;
1986	};
1987
1988	/// Number of inherited and non-inherited bits in LinkageSpecDeclBitfields.
1989	enum { NumLinkageSpecDeclBits = NumDeclContextBits + 4 };
1990
1991	/// Stores the bits used by BlockDecl.
1992	/// If modified NumBlockDeclBits and the accessor
1993	/// methods in BlockDecl should be updated appropriately.
1994	class BlockDeclBitfields {
1995	friend class BlockDecl;
1996	/// For the bits in DeclContextBitfields.
1997	LLVM_PREFERRED_TYPE(DeclContextBitfields)
1998	uint64_t : NumDeclContextBits;
1999
2000	LLVM_PREFERRED_TYPE(bool)
2001	uint64_t IsVariadic : 1;
2002	LLVM_PREFERRED_TYPE(bool)
2003	uint64_t CapturesCXXThis : 1;
2004	LLVM_PREFERRED_TYPE(bool)
2005	uint64_t BlockMissingReturnType : 1;
2006	LLVM_PREFERRED_TYPE(bool)
2007	uint64_t IsConversionFromLambda : 1;
2008
2009	/// A bit that indicates this block is passed directly to a function as a
2010	/// non-escaping parameter.
2011	LLVM_PREFERRED_TYPE(bool)
2012	uint64_t DoesNotEscape : 1;
2013
2014	/// A bit that indicates whether it's possible to avoid coying this block to
2015	/// the heap when it initializes or is assigned to a local variable with
2016	/// automatic storage.
2017	LLVM_PREFERRED_TYPE(bool)
2018	uint64_t CanAvoidCopyToHeap : 1;
2019	};
2020
2021	/// Number of inherited and non-inherited bits in BlockDeclBitfields.
2022	enum { NumBlockDeclBits = NumDeclContextBits + 5 };
2023
2024	/// Pointer to the data structure used to lookup declarations
2025	/// within this context (or a DependentStoredDeclsMap if this is a
2026	/// dependent context). We maintain the invariant that, if the map
2027	/// contains an entry for a DeclarationName (and we haven't lazily
2028	/// omitted anything), then it contains all relevant entries for that
2029	/// name (modulo the hasExternalDecls() flag).
2030	mutable StoredDeclsMap *LookupPtr = nullptr;
2031
2032	protected:
2033	/// This anonymous union stores the bits belonging to DeclContext and classes
2034	/// deriving from it. The goal is to use otherwise wasted
2035	/// space in DeclContext to store data belonging to derived classes.
2036	/// The space saved is especially significient when pointers are aligned
2037	/// to 8 bytes. In this case due to alignment requirements we have a
2038	/// little less than 8 bytes free in DeclContext which we can use.
2039	/// We check that none of the classes in this union is larger than
2040	/// 8 bytes with static_asserts in the ctor of DeclContext.
2041	union {
2042	DeclContextBitfields DeclContextBits;
2043	NamespaceDeclBitfields NamespaceDeclBits;
2044	TagDeclBitfields TagDeclBits;
2045	EnumDeclBitfields EnumDeclBits;
2046	RecordDeclBitfields RecordDeclBits;
2047	OMPDeclareReductionDeclBitfields OMPDeclareReductionDeclBits;
2048	FunctionDeclBitfields FunctionDeclBits;
2049	CXXConstructorDeclBitfields CXXConstructorDeclBits;
2050	ObjCMethodDeclBitfields ObjCMethodDeclBits;
2051	ObjCContainerDeclBitfields ObjCContainerDeclBits;
2052	LinkageSpecDeclBitfields LinkageSpecDeclBits;
2053	BlockDeclBitfields BlockDeclBits;
2054
2055	static_assert(sizeof(DeclContextBitfields) <= 8,
2056	"DeclContextBitfields is larger than 8 bytes!");
2057	static_assert(sizeof(NamespaceDeclBitfields) <= 8,
2058	"NamespaceDeclBitfields is larger than 8 bytes!");
2059	static_assert(sizeof(TagDeclBitfields) <= 8,
2060	"TagDeclBitfields is larger than 8 bytes!");
2061	static_assert(sizeof(EnumDeclBitfields) <= 8,
2062	"EnumDeclBitfields is larger than 8 bytes!");
2063	static_assert(sizeof(RecordDeclBitfields) <= 8,
2064	"RecordDeclBitfields is larger than 8 bytes!");
2065	static_assert(sizeof(OMPDeclareReductionDeclBitfields) <= 8,
2066	"OMPDeclareReductionDeclBitfields is larger than 8 bytes!");
2067	static_assert(sizeof(FunctionDeclBitfields) <= 8,
2068	"FunctionDeclBitfields is larger than 8 bytes!");
2069	static_assert(sizeof(CXXConstructorDeclBitfields) <= 8,
2070	"CXXConstructorDeclBitfields is larger than 8 bytes!");
2071	static_assert(sizeof(ObjCMethodDeclBitfields) <= 8,
2072	"ObjCMethodDeclBitfields is larger than 8 bytes!");
2073	static_assert(sizeof(ObjCContainerDeclBitfields) <= 8,
2074	"ObjCContainerDeclBitfields is larger than 8 bytes!");
2075	static_assert(sizeof(LinkageSpecDeclBitfields) <= 8,
2076	"LinkageSpecDeclBitfields is larger than 8 bytes!");
2077	static_assert(sizeof(BlockDeclBitfields) <= 8,
2078	"BlockDeclBitfields is larger than 8 bytes!");
2079	};
2080
2081	/// FirstDecl - The first declaration stored within this declaration
2082	/// context.
2083	mutable Decl *FirstDecl = nullptr;
2084
2085	/// LastDecl - The last declaration stored within this declaration
2086	/// context. FIXME: We could probably cache this value somewhere
2087	/// outside of the DeclContext, to reduce the size of DeclContext by
2088	/// another pointer.
2089	mutable Decl *LastDecl = nullptr;
2090
2091	/// Build up a chain of declarations.
2092	///
2093	/// \returns the first/last pair of declarations.
2094	static std::pair<Decl *, Decl *>
2095	BuildDeclChain(ArrayRef<Decl*> Decls, bool FieldsAlreadyLoaded);
2096
2097	DeclContext(Decl::Kind K);
2098
2099	public:
2100	~DeclContext();
2101
2102	// For use when debugging; hasValidDeclKind() will always return true for
2103	// a correctly constructed object within its lifetime.
2104	bool hasValidDeclKind() const;
2105
2106	Decl::Kind getDeclKind() const {
2107	return static_cast<Decl::Kind>(DeclContextBits.DeclKind);
2108	}
2109
2110	const char *getDeclKindName() const;
2111
2112	/// getParent - Returns the containing DeclContext.
2113	DeclContext *getParent() {
2114	return cast<Decl>(Val: this)->getDeclContext();
2115	}
2116	const DeclContext *getParent() const {
2117	return const_cast<DeclContext*>(this)->getParent();
2118	}
2119
2120	/// getLexicalParent - Returns the containing lexical DeclContext. May be
2121	/// different from getParent, e.g.:
2122	///
2123	/// namespace A {
2124	/// struct S;
2125	/// }
2126	/// struct A::S {}; // getParent() == namespace 'A'
2127	/// // getLexicalParent() == translation unit
2128	///
2129	DeclContext *getLexicalParent() {
2130	return cast<Decl>(Val: this)->getLexicalDeclContext();
2131	}
2132	const DeclContext *getLexicalParent() const {
2133	return const_cast<DeclContext*>(this)->getLexicalParent();
2134	}
2135
2136	DeclContext *getLookupParent();
2137
2138	const DeclContext *getLookupParent() const {
2139	return const_cast<DeclContext*>(this)->getLookupParent();
2140	}
2141
2142	ASTContext &getParentASTContext() const {
2143	return cast<Decl>(Val: this)->getASTContext();
2144	}
2145
2146	bool isClosure() const { return getDeclKind() == Decl::Block; }
2147
2148	/// Return this DeclContext if it is a BlockDecl. Otherwise, return the
2149	/// innermost enclosing BlockDecl or null if there are no enclosing blocks.
2150	const BlockDecl *getInnermostBlockDecl() const;
2151
2152	bool isObjCContainer() const {
2153	switch (getDeclKind()) {
2154	case Decl::ObjCCategory:
2155	case Decl::ObjCCategoryImpl:
2156	case Decl::ObjCImplementation:
2157	case Decl::ObjCInterface:
2158	case Decl::ObjCProtocol:
2159	return true;
2160	default:
2161	return false;
2162	}
2163	}
2164
2165	bool isFunctionOrMethod() const {
2166	switch (getDeclKind()) {
2167	case Decl::Block:
2168	case Decl::Captured:
2169	case Decl::ObjCMethod:
2170	case Decl::TopLevelStmt:
2171	return true;
2172	default:
2173	return getDeclKind() >= Decl::firstFunction &&
2174	getDeclKind() <= Decl::lastFunction;
2175	}
2176	}
2177
2178	/// Test whether the context supports looking up names.
2179	bool isLookupContext() const {
2180	return !isFunctionOrMethod() && getDeclKind() != Decl::LinkageSpec &&
2181	getDeclKind() != Decl::Export;
2182	}
2183
2184	bool isFileContext() const {
2185	return getDeclKind() == Decl::TranslationUnit ||
2186	getDeclKind() == Decl::Namespace;
2187	}
2188
2189	bool isTranslationUnit() const {
2190	return getDeclKind() == Decl::TranslationUnit;
2191	}
2192
2193	bool isRecord() const {
2194	return getDeclKind() >= Decl::firstRecord &&
2195	getDeclKind() <= Decl::lastRecord;
2196	}
2197
2198	bool isRequiresExprBody() const {
2199	return getDeclKind() == Decl::RequiresExprBody;
2200	}
2201
2202	bool isNamespace() const { return getDeclKind() == Decl::Namespace; }
2203
2204	bool isStdNamespace() const;
2205
2206	bool isInlineNamespace() const;
2207
2208	/// Determines whether this context is dependent on a
2209	/// template parameter.
2210	bool isDependentContext() const;
2211
2212	/// isTransparentContext - Determines whether this context is a
2213	/// "transparent" context, meaning that the members declared in this
2214	/// context are semantically declared in the nearest enclosing
2215	/// non-transparent (opaque) context but are lexically declared in
2216	/// this context. For example, consider the enumerators of an
2217	/// enumeration type:
2218	/// @code
2219	/// enum E {
2220	/// Val1
2221	/// };
2222	/// @endcode
2223	/// Here, E is a transparent context, so its enumerator (Val1) will
2224	/// appear (semantically) that it is in the same context of E.
2225	/// Examples of transparent contexts include: enumerations (except for
2226	/// C++0x scoped enums), C++ linkage specifications and export declaration.
2227	bool isTransparentContext() const;
2228
2229	/// Determines whether this context or some of its ancestors is a
2230	/// linkage specification context that specifies C linkage.
2231	bool isExternCContext() const;
2232
2233	/// Retrieve the nearest enclosing C linkage specification context.
2234	const LinkageSpecDecl *getExternCContext() const;
2235
2236	/// Determines whether this context or some of its ancestors is a
2237	/// linkage specification context that specifies C++ linkage.
2238	bool isExternCXXContext() const;
2239
2240	/// Determine whether this declaration context is equivalent
2241	/// to the declaration context DC.
2242	bool Equals(const DeclContext *DC) const {
2243	return DC && this->getPrimaryContext() == DC->getPrimaryContext();
2244	}
2245
2246	/// Determine whether this declaration context semantically encloses the
2247	/// declaration context DC.
2248	bool Encloses(const DeclContext *DC) const;
2249
2250	/// Determine whether this declaration context lexically encloses the
2251	/// declaration context DC.
2252	bool LexicallyEncloses(const DeclContext *DC) const;
2253
2254	/// Find the nearest non-closure ancestor of this context,
2255	/// i.e. the innermost semantic parent of this context which is not
2256	/// a closure. A context may be its own non-closure ancestor.
2257	Decl *getNonClosureAncestor();
2258	const Decl *getNonClosureAncestor() const {
2259	return const_cast<DeclContext*>(this)->getNonClosureAncestor();
2260	}
2261
2262	// Retrieve the nearest context that is not a transparent context.
2263	DeclContext *getNonTransparentContext();
2264	const DeclContext *getNonTransparentContext() const {
2265	return const_cast<DeclContext *>(this)->getNonTransparentContext();
2266	}
2267
2268	/// getPrimaryContext - There may be many different
2269	/// declarations of the same entity (including forward declarations
2270	/// of classes, multiple definitions of namespaces, etc.), each with
2271	/// a different set of declarations. This routine returns the
2272	/// "primary" DeclContext structure, which will contain the
2273	/// information needed to perform name lookup into this context.
2274	DeclContext *getPrimaryContext();
2275	const DeclContext *getPrimaryContext() const {
2276	return const_cast<DeclContext*>(this)->getPrimaryContext();
2277	}
2278
2279	/// getRedeclContext - Retrieve the context in which an entity conflicts with
2280	/// other entities of the same name, or where it is a redeclaration if the
2281	/// two entities are compatible. This skips through transparent contexts.
2282	DeclContext *getRedeclContext();
2283	const DeclContext *getRedeclContext() const {
2284	return const_cast<DeclContext *>(this)->getRedeclContext();
2285	}
2286
2287	/// Retrieve the nearest enclosing namespace context.
2288	DeclContext *getEnclosingNamespaceContext();
2289	const DeclContext *getEnclosingNamespaceContext() const {
2290	return const_cast<DeclContext *>(this)->getEnclosingNamespaceContext();
2291	}
2292
2293	/// Retrieve the outermost lexically enclosing record context.
2294	RecordDecl *getOuterLexicalRecordContext();
2295	const RecordDecl *getOuterLexicalRecordContext() const {
2296	return const_cast<DeclContext *>(this)->getOuterLexicalRecordContext();
2297	}
2298
2299	/// Test if this context is part of the enclosing namespace set of
2300	/// the context NS, as defined in C++0x [namespace.def]p9. If either context
2301	/// isn't a namespace, this is equivalent to Equals().
2302	///
2303	/// The enclosing namespace set of a namespace is the namespace and, if it is
2304	/// inline, its enclosing namespace, recursively.
2305	bool InEnclosingNamespaceSetOf(const DeclContext *NS) const;
2306
2307	/// Collects all of the declaration contexts that are semantically
2308	/// connected to this declaration context.
2309	///
2310	/// For declaration contexts that have multiple semantically connected but
2311	/// syntactically distinct contexts, such as C++ namespaces, this routine
2312	/// retrieves the complete set of such declaration contexts in source order.
2313	/// For example, given:
2314	///
2315	/// \code
2316	/// namespace N {
2317	/// int x;
2318	/// }
2319	/// namespace N {
2320	/// int y;
2321	/// }
2322	/// \endcode
2323	///
2324	/// The \c Contexts parameter will contain both definitions of N.
2325	///
2326	/// \param Contexts Will be cleared and set to the set of declaration
2327	/// contexts that are semanticaly connected to this declaration context,
2328	/// in source order, including this context (which may be the only result,
2329	/// for non-namespace contexts).
2330	void collectAllContexts(SmallVectorImpl<DeclContext *> &Contexts);
2331
2332	/// decl_iterator - Iterates through the declarations stored
2333	/// within this context.
2334	class decl_iterator {
2335	/// Current - The current declaration.
2336	Decl *Current = nullptr;
2337
2338	public:
2339	using value_type = Decl *;
2340	using reference = const value_type &;
2341	using pointer = const value_type *;
2342	using iterator_category = std::forward_iterator_tag;
2343	using difference_type = std::ptrdiff_t;
2344
2345	decl_iterator() = default;
2346	explicit decl_iterator(Decl *C) : Current(C) {}
2347
2348	reference operator*() const { return Current; }
2349
2350	// This doesn't meet the iterator requirements, but it's convenient
2351	value_type operator->() const { return Current; }
2352
2353	decl_iterator& operator++() {
2354	Current = Current->getNextDeclInContext();
2355	return *this;
2356	}
2357
2358	decl_iterator operator++(int) {
2359	decl_iterator tmp(*this);
2360	++(*this);
2361	return tmp;
2362	}
2363
2364	friend bool operator==(decl_iterator x, decl_iterator y) {
2365	return x.Current == y.Current;
2366	}
2367
2368	friend bool operator!=(decl_iterator x, decl_iterator y) {
2369	return x.Current != y.Current;
2370	}
2371	};
2372
2373	using decl_range = llvm::iterator_range<decl_iterator>;
2374
2375	/// decls_begin/decls_end - Iterate over the declarations stored in
2376	/// this context.
2377	decl_range decls() const { return decl_range(decls_begin(), decls_end()); }
2378	decl_iterator decls_begin() const;
2379	decl_iterator decls_end() const { return decl_iterator(); }
2380	bool decls_empty() const;
2381
2382	/// noload_decls_begin/end - Iterate over the declarations stored in this
2383	/// context that are currently loaded; don't attempt to retrieve anything
2384	/// from an external source.
2385	decl_range noload_decls() const {
2386	return decl_range(noload_decls_begin(), noload_decls_end());
2387	}
2388	decl_iterator noload_decls_begin() const { return decl_iterator(FirstDecl); }
2389	decl_iterator noload_decls_end() const { return decl_iterator(); }
2390
2391	/// specific_decl_iterator - Iterates over a subrange of
2392	/// declarations stored in a DeclContext, providing only those that
2393	/// are of type SpecificDecl (or a class derived from it). This
2394	/// iterator is used, for example, to provide iteration over just
2395	/// the fields within a RecordDecl (with SpecificDecl = FieldDecl).
2396	template<typename SpecificDecl>
2397	class specific_decl_iterator {
2398	/// Current - The current, underlying declaration iterator, which
2399	/// will either be NULL or will point to a declaration of
2400	/// type SpecificDecl.
2401	DeclContext::decl_iterator Current;
2402
2403	/// SkipToNextDecl - Advances the current position up to the next
2404	/// declaration of type SpecificDecl that also meets the criteria
2405	/// required by Acceptable.
2406	void SkipToNextDecl() {
2407	while (*Current && !isa<SpecificDecl>(*Current))
2408	++Current;
2409	}
2410
2411	public:
2412	using value_type = SpecificDecl *;
2413	// TODO: Add reference and pointer types (with some appropriate proxy type)
2414	// if we ever have a need for them.
2415	using reference = void;
2416	using pointer = void;
2417	using difference_type =
2418	std::iterator_traits<DeclContext::decl_iterator>::difference_type;
2419	using iterator_category = std::forward_iterator_tag;
2420
2421	specific_decl_iterator() = default;
2422
2423	/// specific_decl_iterator - Construct a new iterator over a
2424	/// subset of the declarations the range [C,
2425	/// end-of-declarations). If A is non-NULL, it is a pointer to a
2426	/// member function of SpecificDecl that should return true for
2427	/// all of the SpecificDecl instances that will be in the subset
2428	/// of iterators. For example, if you want Objective-C instance
2429	/// methods, SpecificDecl will be ObjCMethodDecl and A will be
2430	/// &ObjCMethodDecl::isInstanceMethod.
2431	explicit specific_decl_iterator(DeclContext::decl_iterator C) : Current(C) {
2432	SkipToNextDecl();
2433	}
2434
2435	value_type operator*() const { return cast<SpecificDecl>(*Current); }
2436
2437	// This doesn't meet the iterator requirements, but it's convenient
2438	value_type operator->() const { return **this; }
2439
2440	specific_decl_iterator& operator++() {
2441	++Current;
2442	SkipToNextDecl();
2443	return *this;
2444	}
2445
2446	specific_decl_iterator operator++(int) {
2447	specific_decl_iterator tmp(*this);
2448	++(*this);
2449	return tmp;
2450	}
2451
2452	friend bool operator==(const specific_decl_iterator& x,
2453	const specific_decl_iterator& y) {
2454	return x.Current == y.Current;
2455	}
2456
2457	friend bool operator!=(const specific_decl_iterator& x,
2458	const specific_decl_iterator& y) {
2459	return x.Current != y.Current;
2460	}
2461	};
2462
2463	/// Iterates over a filtered subrange of declarations stored
2464	/// in a DeclContext.
2465	///
2466	/// This iterator visits only those declarations that are of type
2467	/// SpecificDecl (or a class derived from it) and that meet some
2468	/// additional run-time criteria. This iterator is used, for
2469	/// example, to provide access to the instance methods within an
2470	/// Objective-C interface (with SpecificDecl = ObjCMethodDecl and
2471	/// Acceptable = ObjCMethodDecl::isInstanceMethod).
2472	template<typename SpecificDecl, bool (SpecificDecl::*Acceptable)() const>
2473	class filtered_decl_iterator {
2474	/// Current - The current, underlying declaration iterator, which
2475	/// will either be NULL or will point to a declaration of
2476	/// type SpecificDecl.
2477	DeclContext::decl_iterator Current;
2478
2479	/// SkipToNextDecl - Advances the current position up to the next
2480	/// declaration of type SpecificDecl that also meets the criteria
2481	/// required by Acceptable.
2482	void SkipToNextDecl() {
2483	while (*Current &&
2484	(!isa<SpecificDecl>(*Current) ||
2485	(Acceptable && !(cast<SpecificDecl>(*Current)->*Acceptable)())))
2486	++Current;
2487	}
2488
2489	public:
2490	using value_type = SpecificDecl *;
2491	// TODO: Add reference and pointer types (with some appropriate proxy type)
2492	// if we ever have a need for them.
2493	using reference = void;
2494	using pointer = void;
2495	using difference_type =
2496	std::iterator_traits<DeclContext::decl_iterator>::difference_type;
2497	using iterator_category = std::forward_iterator_tag;
2498
2499	filtered_decl_iterator() = default;
2500
2501	/// filtered_decl_iterator - Construct a new iterator over a
2502	/// subset of the declarations the range [C,
2503	/// end-of-declarations). If A is non-NULL, it is a pointer to a
2504	/// member function of SpecificDecl that should return true for
2505	/// all of the SpecificDecl instances that will be in the subset
2506	/// of iterators. For example, if you want Objective-C instance
2507	/// methods, SpecificDecl will be ObjCMethodDecl and A will be
2508	/// &ObjCMethodDecl::isInstanceMethod.
2509	explicit filtered_decl_iterator(DeclContext::decl_iterator C) : Current(C) {
2510	SkipToNextDecl();
2511	}
2512
2513	value_type operator*() const { return cast<SpecificDecl>(*Current); }
2514	value_type operator->() const { return cast<SpecificDecl>(*Current); }
2515
2516	filtered_decl_iterator& operator++() {
2517	++Current;
2518	SkipToNextDecl();
2519	return *this;
2520	}
2521
2522	filtered_decl_iterator operator++(int) {
2523	filtered_decl_iterator tmp(*this);
2524	++(*this);
2525	return tmp;
2526	}
2527
2528	friend bool operator==(const filtered_decl_iterator& x,
2529	const filtered_decl_iterator& y) {
2530	return x.Current == y.Current;
2531	}
2532
2533	friend bool operator!=(const filtered_decl_iterator& x,
2534	const filtered_decl_iterator& y) {
2535	return x.Current != y.Current;
2536	}
2537	};
2538
2539	/// Add the declaration D into this context.
2540	///
2541	/// This routine should be invoked when the declaration D has first
2542	/// been declared, to place D into the context where it was
2543	/// (lexically) defined. Every declaration must be added to one
2544	/// (and only one!) context, where it can be visited via
2545	/// [decls_begin(), decls_end()). Once a declaration has been added
2546	/// to its lexical context, the corresponding DeclContext owns the
2547	/// declaration.
2548	///
2549	/// If D is also a NamedDecl, it will be made visible within its
2550	/// semantic context via makeDeclVisibleInContext.
2551	void addDecl(Decl *D);
2552
2553	/// Add the declaration D into this context, but suppress
2554	/// searches for external declarations with the same name.
2555	///
2556	/// Although analogous in function to addDecl, this removes an
2557	/// important check. This is only useful if the Decl is being
2558	/// added in response to an external search; in all other cases,
2559	/// addDecl() is the right function to use.
2560	/// See the ASTImporter for use cases.
2561	void addDeclInternal(Decl *D);
2562
2563	/// Add the declaration D to this context without modifying
2564	/// any lookup tables.
2565	///
2566	/// This is useful for some operations in dependent contexts where
2567	/// the semantic context might not be dependent; this basically
2568	/// only happens with friends.
2569	void addHiddenDecl(Decl *D);
2570
2571	/// Removes a declaration from this context.
2572	void removeDecl(Decl *D);
2573
2574	/// Checks whether a declaration is in this context.
2575	bool containsDecl(Decl *D) const;
2576
2577	/// Checks whether a declaration is in this context.
2578	/// This also loads the Decls from the external source before the check.
2579	bool containsDeclAndLoad(Decl *D) const;
2580
2581	using lookup_result = DeclContextLookupResult;
2582	using lookup_iterator = lookup_result::iterator;
2583
2584	/// lookup - Find the declarations (if any) with the given Name in
2585	/// this context. Returns a range of iterators that contains all of
2586	/// the declarations with this name, with object, function, member,
2587	/// and enumerator names preceding any tag name. Note that this
2588	/// routine will not look into parent contexts.
2589	lookup_result lookup(DeclarationName Name) const;
2590
2591	/// Find the declarations with the given name that are visible
2592	/// within this context; don't attempt to retrieve anything from an
2593	/// external source.
2594	lookup_result noload_lookup(DeclarationName Name);
2595
2596	/// A simplistic name lookup mechanism that performs name lookup
2597	/// into this declaration context without consulting the external source.
2598	///
2599	/// This function should almost never be used, because it subverts the
2600	/// usual relationship between a DeclContext and the external source.
2601	/// See the ASTImporter for the (few, but important) use cases.
2602	///
2603	/// FIXME: This is very inefficient; replace uses of it with uses of
2604	/// noload_lookup.
2605	void localUncachedLookup(DeclarationName Name,
2606	SmallVectorImpl<NamedDecl *> &Results);
2607
2608	/// Makes a declaration visible within this context.
2609	///
2610	/// This routine makes the declaration D visible to name lookup
2611	/// within this context and, if this is a transparent context,
2612	/// within its parent contexts up to the first enclosing
2613	/// non-transparent context. Making a declaration visible within a
2614	/// context does not transfer ownership of a declaration, and a
2615	/// declaration can be visible in many contexts that aren't its
2616	/// lexical context.
2617	///
2618	/// If D is a redeclaration of an existing declaration that is
2619	/// visible from this context, as determined by
2620	/// NamedDecl::declarationReplaces, the previous declaration will be
2621	/// replaced with D.
2622	void makeDeclVisibleInContext(NamedDecl *D);
2623
2624	/// all_lookups_iterator - An iterator that provides a view over the results
2625	/// of looking up every possible name.
2626	class all_lookups_iterator;
2627
2628	using lookups_range = llvm::iterator_range<all_lookups_iterator>;
2629
2630	lookups_range lookups() const;
2631	// Like lookups(), but avoids loading external declarations.
2632	// If PreserveInternalState, avoids building lookup data structures too.
2633	lookups_range noload_lookups(bool PreserveInternalState) const;
2634
2635	/// Iterators over all possible lookups within this context.
2636	all_lookups_iterator lookups_begin() const;
2637	all_lookups_iterator lookups_end() const;
2638
2639	/// Iterators over all possible lookups within this context that are
2640	/// currently loaded; don't attempt to retrieve anything from an external
2641	/// source.
2642	all_lookups_iterator noload_lookups_begin() const;
2643	all_lookups_iterator noload_lookups_end() const;
2644
2645	struct udir_iterator;
2646
2647	using udir_iterator_base =
2648	llvm::iterator_adaptor_base<udir_iterator, lookup_iterator,
2649	typename lookup_iterator::iterator_category,
2650	UsingDirectiveDecl *>;
2651
2652	struct udir_iterator : udir_iterator_base {
2653	udir_iterator(lookup_iterator I) : udir_iterator_base(I) {}
2654
2655	UsingDirectiveDecl *operator*() const;
2656	};
2657
2658	using udir_range = llvm::iterator_range<udir_iterator>;
2659
2660	udir_range using_directives() const;
2661
2662	// These are all defined in DependentDiagnostic.h.
2663	class ddiag_iterator;
2664
2665	using ddiag_range = llvm::iterator_range<DeclContext::ddiag_iterator>;
2666
2667	inline ddiag_range ddiags() const;
2668
2669	// Low-level accessors
2670
2671	/// Mark that there are external lexical declarations that we need
2672	/// to include in our lookup table (and that are not available as external
2673	/// visible lookups). These extra lookup results will be found by walking
2674	/// the lexical declarations of this context. This should be used only if
2675	/// setHasExternalLexicalStorage() has been called on any decl context for
2676	/// which this is the primary context.
2677	void setMustBuildLookupTable() {
2678	assert(this == getPrimaryContext() &&
2679	"should only be called on primary context");
2680	DeclContextBits.HasLazyExternalLexicalLookups = true;
2681	}
2682
2683	/// Retrieve the internal representation of the lookup structure.
2684	/// This may omit some names if we are lazily building the structure.
2685	StoredDeclsMap *getLookupPtr() const { return LookupPtr; }
2686
2687	/// Ensure the lookup structure is fully-built and return it.
2688	StoredDeclsMap *buildLookup();
2689
2690	/// Whether this DeclContext has external storage containing
2691	/// additional declarations that are lexically in this context.
2692	bool hasExternalLexicalStorage() const {
2693	return DeclContextBits.ExternalLexicalStorage;
2694	}
2695
2696	/// State whether this DeclContext has external storage for
2697	/// declarations lexically in this context.
2698	void setHasExternalLexicalStorage(bool ES = true) const {
2699	DeclContextBits.ExternalLexicalStorage = ES;
2700	}
2701
2702	/// Whether this DeclContext has external storage containing
2703	/// additional declarations that are visible in this context.
2704	bool hasExternalVisibleStorage() const {
2705	return DeclContextBits.ExternalVisibleStorage;
2706	}
2707
2708	/// State whether this DeclContext has external storage for
2709	/// declarations visible in this context.
2710	void setHasExternalVisibleStorage(bool ES = true) const {
2711	DeclContextBits.ExternalVisibleStorage = ES;
2712	if (ES && LookupPtr)
2713	DeclContextBits.NeedToReconcileExternalVisibleStorage = true;
2714	}
2715
2716	/// Determine whether the given declaration is stored in the list of
2717	/// declarations lexically within this context.
2718	bool isDeclInLexicalTraversal(const Decl *D) const {
2719	return D && (D->NextInContextAndBits.getPointer() || D == FirstDecl ||
2720	D == LastDecl);
2721	}
2722
2723	void setUseQualifiedLookup(bool use = true) const {
2724	DeclContextBits.UseQualifiedLookup = use;
2725	}
2726
2727	bool shouldUseQualifiedLookup() const {
2728	return DeclContextBits.UseQualifiedLookup;
2729	}
2730
2731	static bool classof(const Decl *D);
2732	static bool classof(const DeclContext *D) { return true; }
2733
2734	void dumpAsDecl() const;
2735	void dumpAsDecl(const ASTContext *Ctx) const;
2736	void dumpDeclContext() const;
2737	void dumpLookups() const;
2738	void dumpLookups(llvm::raw_ostream &OS, bool DumpDecls = false,
2739	bool Deserialize = false) const;
2740
2741	private:
2742	lookup_result lookupImpl(DeclarationName Name,
2743	const DeclContext *OriginalLookupDC) const;
2744
2745	/// Whether this declaration context has had externally visible
2746	/// storage added since the last lookup. In this case, \c LookupPtr's
2747	/// invariant may not hold and needs to be fixed before we perform
2748	/// another lookup.
2749	bool hasNeedToReconcileExternalVisibleStorage() const {
2750	return DeclContextBits.NeedToReconcileExternalVisibleStorage;
2751	}
2752
2753	/// State that this declaration context has had externally visible
2754	/// storage added since the last lookup. In this case, \c LookupPtr's
2755	/// invariant may not hold and needs to be fixed before we perform
2756	/// another lookup.
2757	void setNeedToReconcileExternalVisibleStorage(bool Need = true) const {
2758	DeclContextBits.NeedToReconcileExternalVisibleStorage = Need;
2759	}
2760
2761	/// If \c true, this context may have local lexical declarations
2762	/// that are missing from the lookup table.
2763	bool hasLazyLocalLexicalLookups() const {
2764	return DeclContextBits.HasLazyLocalLexicalLookups;
2765	}
2766
2767	/// If \c true, this context may have local lexical declarations
2768	/// that are missing from the lookup table.
2769	void setHasLazyLocalLexicalLookups(bool HasLLLL = true) const {
2770	DeclContextBits.HasLazyLocalLexicalLookups = HasLLLL;
2771	}
2772
2773	/// If \c true, the external source may have lexical declarations
2774	/// that are missing from the lookup table.
2775	bool hasLazyExternalLexicalLookups() const {
2776	return DeclContextBits.HasLazyExternalLexicalLookups;
2777	}
2778
2779	/// If \c true, the external source may have lexical declarations
2780	/// that are missing from the lookup table.
2781	void setHasLazyExternalLexicalLookups(bool HasLELL = true) const {
2782	DeclContextBits.HasLazyExternalLexicalLookups = HasLELL;
2783	}
2784
2785	void reconcileExternalVisibleStorage() const;
2786	bool LoadLexicalDeclsFromExternalStorage() const;
2787
2788	StoredDeclsMap *CreateStoredDeclsMap(ASTContext &C) const;
2789
2790	void loadLazyLocalLexicalLookups();
2791	void buildLookupImpl(DeclContext *DCtx, bool Internal);
2792	void makeDeclVisibleInContextWithFlags(NamedDecl *D, bool Internal,
2793	bool Rediscoverable);
2794	void makeDeclVisibleInContextImpl(NamedDecl *D, bool Internal);
2795	};
2796
2797	inline bool Decl::isTemplateParameter() const {
2798	return getKind() == TemplateTypeParm || getKind() == NonTypeTemplateParm ||
2799	getKind() == TemplateTemplateParm;
2800	}
2801
2802	// Specialization selected when ToTy is not a known subclass of DeclContext.
2803	template <class ToTy,
2804	bool IsKnownSubtype = ::std::is_base_of<DeclContext, ToTy>::value>
2805	struct cast_convert_decl_context {
2806	static const ToTy *doit(const DeclContext *Val) {
2807	return static_cast<const ToTy*>(Decl::castFromDeclContext(Val));
2808	}
2809
2810	static ToTy *doit(DeclContext *Val) {
2811	return static_cast<ToTy*>(Decl::castFromDeclContext(Val));
2812	}
2813	};
2814
2815	// Specialization selected when ToTy is a known subclass of DeclContext.
2816	template <class ToTy>
2817	struct cast_convert_decl_context<ToTy, true> {
2818	static const ToTy *doit(const DeclContext *Val) {
2819	return static_cast<const ToTy*>(Val);
2820	}
2821
2822	static ToTy *doit(DeclContext *Val) {
2823	return static_cast<ToTy*>(Val);
2824	}
2825	};
2826
2827	} // namespace clang
2828
2829	namespace llvm {
2830
2831	/// isa<T>(DeclContext*)
2832	template <typename To>
2833	struct isa_impl<To, ::clang::DeclContext> {
2834	static bool doit(const ::clang::DeclContext &Val) {
2835	return To::classofKind(Val.getDeclKind());
2836	}
2837	};
2838
2839	/// cast<T>(DeclContext*)
2840	template<class ToTy>
2841	struct cast_convert_val<ToTy,
2842	const ::clang::DeclContext,const ::clang::DeclContext> {
2843	static const ToTy &doit(const ::clang::DeclContext &Val) {
2844	return *::clang::cast_convert_decl_context<ToTy>::doit(&Val);
2845	}
2846	};
2847
2848	template<class ToTy>
2849	struct cast_convert_val<ToTy, ::clang::DeclContext, ::clang::DeclContext> {
2850	static ToTy &doit(::clang::DeclContext &Val) {
2851	return *::clang::cast_convert_decl_context<ToTy>::doit(&Val);
2852	}
2853	};
2854
2855	template<class ToTy>
2856	struct cast_convert_val<ToTy,
2857	const ::clang::DeclContext*, const ::clang::DeclContext*> {
2858	static const ToTy *doit(const ::clang::DeclContext *Val) {
2859	return ::clang::cast_convert_decl_context<ToTy>::doit(Val);
2860	}
2861	};
2862
2863	template<class ToTy>
2864	struct cast_convert_val<ToTy, ::clang::DeclContext*, ::clang::DeclContext*> {
2865	static ToTy *doit(::clang::DeclContext *Val) {
2866	return ::clang::cast_convert_decl_context<ToTy>::doit(Val);
2867	}
2868	};
2869
2870	/// Implement cast_convert_val for Decl -> DeclContext conversions.
2871	template<class FromTy>
2872	struct cast_convert_val< ::clang::DeclContext, FromTy, FromTy> {
2873	static ::clang::DeclContext &doit(const FromTy &Val) {
2874	return *FromTy::castToDeclContext(&Val);
2875	}
2876	};
2877
2878	template<class FromTy>
2879	struct cast_convert_val< ::clang::DeclContext, FromTy*, FromTy*> {
2880	static ::clang::DeclContext *doit(const FromTy *Val) {
2881	return FromTy::castToDeclContext(Val);
2882	}
2883	};
2884
2885	template<class FromTy>
2886	struct cast_convert_val< const ::clang::DeclContext, FromTy, FromTy> {
2887	static const ::clang::DeclContext &doit(const FromTy &Val) {
2888	return *FromTy::castToDeclContext(&Val);
2889	}
2890	};
2891
2892	template<class FromTy>
2893	struct cast_convert_val< const ::clang::DeclContext, FromTy*, FromTy*> {
2894	static const ::clang::DeclContext *doit(const FromTy *Val) {
2895	return FromTy::castToDeclContext(Val);
2896	}
2897	};
2898
2899	} // namespace llvm
2900
2901	#endif // LLVM_CLANG_AST_DECLBASE_H
2902