1	//=== RecordLayoutBuilder.cpp - Helper class for building record layouts ---==//
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	#include "clang/AST/ASTContext.h"
10	#include "clang/AST/ASTDiagnostic.h"
11	#include "clang/AST/Attr.h"
12	#include "clang/AST/CXXInheritance.h"
13	#include "clang/AST/Decl.h"
14	#include "clang/AST/DeclCXX.h"
15	#include "clang/AST/DeclObjC.h"
16	#include "clang/AST/Expr.h"
17	#include "clang/AST/RecordLayout.h"
18	#include "clang/AST/VTableBuilder.h"
19	#include "clang/Basic/TargetInfo.h"
20	#include "llvm/Support/Format.h"
21	#include "llvm/Support/MathExtras.h"
22
23	using namespace clang;
24
25	namespace {
26
27	/// BaseSubobjectInfo - Represents a single base subobject in a complete class.
28	/// For a class hierarchy like
29	///
30	/// class A { };
31	/// class B : A { };
32	/// class C : A, B { };
33	///
34	/// The BaseSubobjectInfo graph for C will have three BaseSubobjectInfo
35	/// instances, one for B and two for A.
36	///
37	/// If a base is virtual, it will only have one BaseSubobjectInfo allocated.
38	struct BaseSubobjectInfo {
39	/// Class - The class for this base info.
40	const CXXRecordDecl *Class;
41
42	/// IsVirtual - Whether the BaseInfo represents a virtual base or not.
43	bool IsVirtual;
44
45	/// Bases - Information about the base subobjects.
46	SmallVector<BaseSubobjectInfo*, 4> Bases;
47
48	/// PrimaryVirtualBaseInfo - Holds the base info for the primary virtual base
49	/// of this base info (if one exists).
50	BaseSubobjectInfo *PrimaryVirtualBaseInfo;
51
52	// FIXME: Document.
53	const BaseSubobjectInfo *Derived;
54	};
55
56	/// Externally provided layout. Typically used when the AST source, such
57	/// as DWARF, lacks all the information that was available at compile time, such
58	/// as alignment attributes on fields and pragmas in effect.
59	struct ExternalLayout {
60	ExternalLayout() = default;
61
62	/// Overall record size in bits.
63	uint64_t Size = 0;
64
65	/// Overall record alignment in bits.
66	uint64_t Align = 0;
67
68	/// Record field offsets in bits.
69	llvm::DenseMap<const FieldDecl *, uint64_t> FieldOffsets;
70
71	/// Direct, non-virtual base offsets.
72	llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsets;
73
74	/// Virtual base offsets.
75	llvm::DenseMap<const CXXRecordDecl *, CharUnits> VirtualBaseOffsets;
76
77	/// Get the offset of the given field. The external source must provide
78	/// entries for all fields in the record.
79	uint64_t getExternalFieldOffset(const FieldDecl *FD) {
80	assert(FieldOffsets.count(FD) &&
81	"Field does not have an external offset");
82	return FieldOffsets[FD];
83	}
84
85	bool getExternalNVBaseOffset(const CXXRecordDecl *RD, CharUnits &BaseOffset) {
86	auto Known = BaseOffsets.find(Val: RD);
87	if (Known == BaseOffsets.end())
88	return false;
89	BaseOffset = Known->second;
90	return true;
91	}
92
93	bool getExternalVBaseOffset(const CXXRecordDecl *RD, CharUnits &BaseOffset) {
94	auto Known = VirtualBaseOffsets.find(Val: RD);
95	if (Known == VirtualBaseOffsets.end())
96	return false;
97	BaseOffset = Known->second;
98	return true;
99	}
100	};
101
102	/// EmptySubobjectMap - Keeps track of which empty subobjects exist at different
103	/// offsets while laying out a C++ class.
104	class EmptySubobjectMap {
105	const ASTContext &Context;
106	uint64_t CharWidth;
107
108	/// Class - The class whose empty entries we're keeping track of.
109	const CXXRecordDecl *Class;
110
111	/// EmptyClassOffsets - A map from offsets to empty record decls.
112	typedef llvm::TinyPtrVector<const CXXRecordDecl *> ClassVectorTy;
113	typedef llvm::DenseMap<CharUnits, ClassVectorTy> EmptyClassOffsetsMapTy;
114	EmptyClassOffsetsMapTy EmptyClassOffsets;
115
116	/// MaxEmptyClassOffset - The highest offset known to contain an empty
117	/// base subobject.
118	CharUnits MaxEmptyClassOffset;
119
120	/// ComputeEmptySubobjectSizes - Compute the size of the largest base or
121	/// member subobject that is empty.
122	void ComputeEmptySubobjectSizes();
123
124	void AddSubobjectAtOffset(const CXXRecordDecl *RD, CharUnits Offset);
125
126	void UpdateEmptyBaseSubobjects(const BaseSubobjectInfo *Info,
127	CharUnits Offset, bool PlacingEmptyBase);
128
129	void UpdateEmptyFieldSubobjects(const CXXRecordDecl *RD,
130	const CXXRecordDecl *Class, CharUnits Offset,
131	bool PlacingOverlappingField);
132	void UpdateEmptyFieldSubobjects(const FieldDecl *FD, CharUnits Offset,
133	bool PlacingOverlappingField);
134
135	/// AnyEmptySubobjectsBeyondOffset - Returns whether there are any empty
136	/// subobjects beyond the given offset.
137	bool AnyEmptySubobjectsBeyondOffset(CharUnits Offset) const {
138	return Offset <= MaxEmptyClassOffset;
139	}
140
141	CharUnits getFieldOffset(const ASTRecordLayout &Layout,
142	const FieldDecl *Field) const {
143	uint64_t FieldOffset = Layout.getFieldOffset(FieldNo: Field->getFieldIndex());
144	assert(FieldOffset % CharWidth == 0 &&
145	"Field offset not at char boundary!");
146
147	return Context.toCharUnitsFromBits(BitSize: FieldOffset);
148	}
149
150	protected:
151	bool CanPlaceSubobjectAtOffset(const CXXRecordDecl *RD,
152	CharUnits Offset) const;
153
154	bool CanPlaceBaseSubobjectAtOffset(const BaseSubobjectInfo *Info,
155	CharUnits Offset);
156
157	bool CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD,
158	const CXXRecordDecl *Class,
159	CharUnits Offset) const;
160	bool CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD,
161	CharUnits Offset) const;
162
163	public:
164	/// This holds the size of the largest empty subobject (either a base
165	/// or a member). Will be zero if the record being built doesn't contain
166	/// any empty classes.
167	CharUnits SizeOfLargestEmptySubobject;
168
169	EmptySubobjectMap(const ASTContext &Context, const CXXRecordDecl *Class)
170	: Context(Context), CharWidth(Context.getCharWidth()), Class(Class) {
171	ComputeEmptySubobjectSizes();
172	}
173
174	/// CanPlaceBaseAtOffset - Return whether the given base class can be placed
175	/// at the given offset.
176	/// Returns false if placing the record will result in two components
177	/// (direct or indirect) of the same type having the same offset.
178	bool CanPlaceBaseAtOffset(const BaseSubobjectInfo *Info,
179	CharUnits Offset);
180
181	/// CanPlaceFieldAtOffset - Return whether a field can be placed at the given
182	/// offset.
183	bool CanPlaceFieldAtOffset(const FieldDecl *FD, CharUnits Offset);
184	};
185
186	void EmptySubobjectMap::ComputeEmptySubobjectSizes() {
187	// Check the bases.
188	for (const CXXBaseSpecifier &Base : Class->bases()) {
189	const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
190
191	CharUnits EmptySize;
192	const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
193	if (BaseDecl->isEmpty()) {
194	// If the class decl is empty, get its size.
195	EmptySize = Layout.getSize();
196	} else {
197	// Otherwise, we get the largest empty subobject for the decl.
198	EmptySize = Layout.getSizeOfLargestEmptySubobject();
199	}
200
201	if (EmptySize > SizeOfLargestEmptySubobject)
202	SizeOfLargestEmptySubobject = EmptySize;
203	}
204
205	// Check the fields.
206	for (const FieldDecl *FD : Class->fields()) {
207	const RecordType *RT =
208	Context.getBaseElementType(FD->getType())->getAs<RecordType>();
209
210	// We only care about record types.
211	if (!RT)
212	continue;
213
214	CharUnits EmptySize;
215	const CXXRecordDecl *MemberDecl = RT->getAsCXXRecordDecl();
216	const ASTRecordLayout &Layout = Context.getASTRecordLayout(MemberDecl);
217	if (MemberDecl->isEmpty()) {
218	// If the class decl is empty, get its size.
219	EmptySize = Layout.getSize();
220	} else {
221	// Otherwise, we get the largest empty subobject for the decl.
222	EmptySize = Layout.getSizeOfLargestEmptySubobject();
223	}
224
225	if (EmptySize > SizeOfLargestEmptySubobject)
226	SizeOfLargestEmptySubobject = EmptySize;
227	}
228	}
229
230	bool
231	EmptySubobjectMap::CanPlaceSubobjectAtOffset(const CXXRecordDecl *RD,
232	CharUnits Offset) const {
233	// We only need to check empty bases.
234	if (!RD->isEmpty())
235	return true;
236
237	EmptyClassOffsetsMapTy::const_iterator I = EmptyClassOffsets.find(Val: Offset);
238	if (I == EmptyClassOffsets.end())
239	return true;
240
241	const ClassVectorTy &Classes = I->second;
242	if (!llvm::is_contained(Range: Classes, Element: RD))
243	return true;
244
245	// There is already an empty class of the same type at this offset.
246	return false;
247	}
248
249	void EmptySubobjectMap::AddSubobjectAtOffset(const CXXRecordDecl *RD,
250	CharUnits Offset) {
251	// We only care about empty bases.
252	if (!RD->isEmpty())
253	return;
254
255	// If we have empty structures inside a union, we can assign both
256	// the same offset. Just avoid pushing them twice in the list.
257	ClassVectorTy &Classes = EmptyClassOffsets[Offset];
258	if (llvm::is_contained(Range&: Classes, Element: RD))
259	return;
260
261	Classes.push_back(NewVal: RD);
262
263	// Update the empty class offset.
264	if (Offset > MaxEmptyClassOffset)
265	MaxEmptyClassOffset = Offset;
266	}
267
268	bool
269	EmptySubobjectMap::CanPlaceBaseSubobjectAtOffset(const BaseSubobjectInfo *Info,
270	CharUnits Offset) {
271	// We don't have to keep looking past the maximum offset that's known to
272	// contain an empty class.
273	if (!AnyEmptySubobjectsBeyondOffset(Offset))
274	return true;
275
276	if (!CanPlaceSubobjectAtOffset(RD: Info->Class, Offset))
277	return false;
278
279	// Traverse all non-virtual bases.
280	const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
281	for (const BaseSubobjectInfo *Base : Info->Bases) {
282	if (Base->IsVirtual)
283	continue;
284
285	CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base: Base->Class);
286
287	if (!CanPlaceBaseSubobjectAtOffset(Info: Base, Offset: BaseOffset))
288	return false;
289	}
290
291	if (Info->PrimaryVirtualBaseInfo) {
292	BaseSubobjectInfo *PrimaryVirtualBaseInfo = Info->PrimaryVirtualBaseInfo;
293
294	if (Info == PrimaryVirtualBaseInfo->Derived) {
295	if (!CanPlaceBaseSubobjectAtOffset(Info: PrimaryVirtualBaseInfo, Offset))
296	return false;
297	}
298	}
299
300	// Traverse all member variables.
301	for (const FieldDecl *Field : Info->Class->fields()) {
302	if (Field->isBitField())
303	continue;
304
305	CharUnits FieldOffset = Offset + getFieldOffset(Layout, Field);
306	if (!CanPlaceFieldSubobjectAtOffset(Field, FieldOffset))
307	return false;
308	}
309
310	return true;
311	}
312
313	void EmptySubobjectMap::UpdateEmptyBaseSubobjects(const BaseSubobjectInfo *Info,
314	CharUnits Offset,
315	bool PlacingEmptyBase) {
316	if (!PlacingEmptyBase && Offset >= SizeOfLargestEmptySubobject) {
317	// We know that the only empty subobjects that can conflict with empty
318	// subobject of non-empty bases, are empty bases that can be placed at
319	// offset zero. Because of this, we only need to keep track of empty base
320	// subobjects with offsets less than the size of the largest empty
321	// subobject for our class.
322	return;
323	}
324
325	AddSubobjectAtOffset(RD: Info->Class, Offset);
326
327	// Traverse all non-virtual bases.
328	const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
329	for (const BaseSubobjectInfo *Base : Info->Bases) {
330	if (Base->IsVirtual)
331	continue;
332
333	CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base: Base->Class);
334	UpdateEmptyBaseSubobjects(Info: Base, Offset: BaseOffset, PlacingEmptyBase);
335	}
336
337	if (Info->PrimaryVirtualBaseInfo) {
338	BaseSubobjectInfo *PrimaryVirtualBaseInfo = Info->PrimaryVirtualBaseInfo;
339
340	if (Info == PrimaryVirtualBaseInfo->Derived)
341	UpdateEmptyBaseSubobjects(Info: PrimaryVirtualBaseInfo, Offset,
342	PlacingEmptyBase);
343	}
344
345	// Traverse all member variables.
346	for (const FieldDecl *Field : Info->Class->fields()) {
347	if (Field->isBitField())
348	continue;
349
350	CharUnits FieldOffset = Offset + getFieldOffset(Layout, Field);
351	UpdateEmptyFieldSubobjects(Field, FieldOffset, PlacingEmptyBase);
352	}
353	}
354
355	bool EmptySubobjectMap::CanPlaceBaseAtOffset(const BaseSubobjectInfo *Info,
356	CharUnits Offset) {
357	// If we know this class doesn't have any empty subobjects we don't need to
358	// bother checking.
359	if (SizeOfLargestEmptySubobject.isZero())
360	return true;
361
362	if (!CanPlaceBaseSubobjectAtOffset(Info, Offset))
363	return false;
364
365	// We are able to place the base at this offset. Make sure to update the
366	// empty base subobject map.
367	UpdateEmptyBaseSubobjects(Info, Offset, PlacingEmptyBase: Info->Class->isEmpty());
368	return true;
369	}
370
371	bool
372	EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD,
373	const CXXRecordDecl *Class,
374	CharUnits Offset) const {
375	// We don't have to keep looking past the maximum offset that's known to
376	// contain an empty class.
377	if (!AnyEmptySubobjectsBeyondOffset(Offset))
378	return true;
379
380	if (!CanPlaceSubobjectAtOffset(RD, Offset))
381	return false;
382
383	const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
384
385	// Traverse all non-virtual bases.
386	for (const CXXBaseSpecifier &Base : RD->bases()) {
387	if (Base.isVirtual())
388	continue;
389
390	const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
391
392	CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base: BaseDecl);
393	if (!CanPlaceFieldSubobjectAtOffset(RD: BaseDecl, Class, Offset: BaseOffset))
394	return false;
395	}
396
397	if (RD == Class) {
398	// This is the most derived class, traverse virtual bases as well.
399	for (const CXXBaseSpecifier &Base : RD->vbases()) {
400	const CXXRecordDecl *VBaseDecl = Base.getType()->getAsCXXRecordDecl();
401
402	CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBase: VBaseDecl);
403	if (!CanPlaceFieldSubobjectAtOffset(RD: VBaseDecl, Class, Offset: VBaseOffset))
404	return false;
405	}
406	}
407
408	// Traverse all member variables.
409	for (const FieldDecl *Field : RD->fields()) {
410	if (Field->isBitField())
411	continue;
412
413	CharUnits FieldOffset = Offset + getFieldOffset(Layout, Field);
414	if (!CanPlaceFieldSubobjectAtOffset(Field, FieldOffset))
415	return false;
416	}
417
418	return true;
419	}
420
421	bool
422	EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD,
423	CharUnits Offset) const {
424	// We don't have to keep looking past the maximum offset that's known to
425	// contain an empty class.
426	if (!AnyEmptySubobjectsBeyondOffset(Offset))
427	return true;
428
429	QualType T = FD->getType();
430	if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
431	return CanPlaceFieldSubobjectAtOffset(RD, Class: RD, Offset);
432
433	// If we have an array type we need to look at every element.
434	if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
435	QualType ElemTy = Context.getBaseElementType(AT);
436	const RecordType *RT = ElemTy->getAs<RecordType>();
437	if (!RT)
438	return true;
439
440	const CXXRecordDecl *RD = RT->getAsCXXRecordDecl();
441	const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
442
443	uint64_t NumElements = Context.getConstantArrayElementCount(CA: AT);
444	CharUnits ElementOffset = Offset;
445	for (uint64_t I = 0; I != NumElements; ++I) {
446	// We don't have to keep looking past the maximum offset that's known to
447	// contain an empty class.
448	if (!AnyEmptySubobjectsBeyondOffset(Offset: ElementOffset))
449	return true;
450
451	if (!CanPlaceFieldSubobjectAtOffset(RD, Class: RD, Offset: ElementOffset))
452	return false;
453
454	ElementOffset += Layout.getSize();
455	}
456	}
457
458	return true;
459	}
460
461	bool EmptySubobjectMap::CanPlaceFieldAtOffset(const FieldDecl *FD,
462	CharUnits Offset) {
463	if (!CanPlaceFieldSubobjectAtOffset(FD, Offset))
464	return false;
465
466	// We are able to place the member variable at this offset.
467	// Make sure to update the empty field subobject map.
468	UpdateEmptyFieldSubobjects(FD, Offset, FD->hasAttr<NoUniqueAddressAttr>());
469	return true;
470	}
471
472	void EmptySubobjectMap::UpdateEmptyFieldSubobjects(
473	const CXXRecordDecl *RD, const CXXRecordDecl *Class, CharUnits Offset,
474	bool PlacingOverlappingField) {
475	// We know that the only empty subobjects that can conflict with empty
476	// field subobjects are subobjects of empty bases and potentially-overlapping
477	// fields that can be placed at offset zero. Because of this, we only need to
478	// keep track of empty field subobjects with offsets less than the size of
479	// the largest empty subobject for our class.
480	//
481	// (Proof: we will only consider placing a subobject at offset zero or at
482	// >= the current dsize. The only cases where the earlier subobject can be
483	// placed beyond the end of dsize is if it's an empty base or a
484	// potentially-overlapping field.)
485	if (!PlacingOverlappingField && Offset >= SizeOfLargestEmptySubobject)
486	return;
487
488	AddSubobjectAtOffset(RD, Offset);
489
490	const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
491
492	// Traverse all non-virtual bases.
493	for (const CXXBaseSpecifier &Base : RD->bases()) {
494	if (Base.isVirtual())
495	continue;
496
497	const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
498
499	CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base: BaseDecl);
500	UpdateEmptyFieldSubobjects(RD: BaseDecl, Class, Offset: BaseOffset,
501	PlacingOverlappingField);
502	}
503
504	if (RD == Class) {
505	// This is the most derived class, traverse virtual bases as well.
506	for (const CXXBaseSpecifier &Base : RD->vbases()) {
507	const CXXRecordDecl *VBaseDecl = Base.getType()->getAsCXXRecordDecl();
508
509	CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBase: VBaseDecl);
510	UpdateEmptyFieldSubobjects(RD: VBaseDecl, Class, Offset: VBaseOffset,
511	PlacingOverlappingField);
512	}
513	}
514
515	// Traverse all member variables.
516	for (const FieldDecl *Field : RD->fields()) {
517	if (Field->isBitField())
518	continue;
519
520	CharUnits FieldOffset = Offset + getFieldOffset(Layout, Field);
521	UpdateEmptyFieldSubobjects(Field, FieldOffset, PlacingOverlappingField);
522	}
523	}
524
525	void EmptySubobjectMap::UpdateEmptyFieldSubobjects(
526	const FieldDecl *FD, CharUnits Offset, bool PlacingOverlappingField) {
527	QualType T = FD->getType();
528	if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl()) {
529	UpdateEmptyFieldSubobjects(RD, Class: RD, Offset, PlacingOverlappingField);
530	return;
531	}
532
533	// If we have an array type we need to update every element.
534	if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
535	QualType ElemTy = Context.getBaseElementType(AT);
536	const RecordType *RT = ElemTy->getAs<RecordType>();
537	if (!RT)
538	return;
539
540	const CXXRecordDecl *RD = RT->getAsCXXRecordDecl();
541	const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
542
543	uint64_t NumElements = Context.getConstantArrayElementCount(CA: AT);
544	CharUnits ElementOffset = Offset;
545
546	for (uint64_t I = 0; I != NumElements; ++I) {
547	// We know that the only empty subobjects that can conflict with empty
548	// field subobjects are subobjects of empty bases that can be placed at
549	// offset zero. Because of this, we only need to keep track of empty field
550	// subobjects with offsets less than the size of the largest empty
551	// subobject for our class.
552	if (!PlacingOverlappingField &&
553	ElementOffset >= SizeOfLargestEmptySubobject)
554	return;
555
556	UpdateEmptyFieldSubobjects(RD, Class: RD, Offset: ElementOffset,
557	PlacingOverlappingField);
558	ElementOffset += Layout.getSize();
559	}
560	}
561	}
562
563	typedef llvm::SmallPtrSet<const CXXRecordDecl*, 4> ClassSetTy;
564
565	class ItaniumRecordLayoutBuilder {
566	protected:
567	// FIXME: Remove this and make the appropriate fields public.
568	friend class clang::ASTContext;
569
570	const ASTContext &Context;
571
572	EmptySubobjectMap *EmptySubobjects;
573
574	/// Size - The current size of the record layout.
575	uint64_t Size;
576
577	/// Alignment - The current alignment of the record layout.
578	CharUnits Alignment;
579
580	/// PreferredAlignment - The preferred alignment of the record layout.
581	CharUnits PreferredAlignment;
582
583	/// The alignment if attribute packed is not used.
584	CharUnits UnpackedAlignment;
585
586	/// \brief The maximum of the alignments of top-level members.
587	CharUnits UnadjustedAlignment;
588
589	SmallVector<uint64_t, 16> FieldOffsets;
590
591	/// Whether the external AST source has provided a layout for this
592	/// record.
593	LLVM_PREFERRED_TYPE(bool)
594	unsigned UseExternalLayout : 1;
595
596	/// Whether we need to infer alignment, even when we have an
597	/// externally-provided layout.
598	LLVM_PREFERRED_TYPE(bool)
599	unsigned InferAlignment : 1;
600
601	/// Packed - Whether the record is packed or not.
602	LLVM_PREFERRED_TYPE(bool)
603	unsigned Packed : 1;
604
605	LLVM_PREFERRED_TYPE(bool)
606	unsigned IsUnion : 1;
607
608	LLVM_PREFERRED_TYPE(bool)
609	unsigned IsMac68kAlign : 1;
610
611	LLVM_PREFERRED_TYPE(bool)
612	unsigned IsNaturalAlign : 1;
613
614	LLVM_PREFERRED_TYPE(bool)
615	unsigned IsMsStruct : 1;
616
617	/// UnfilledBitsInLastUnit - If the last field laid out was a bitfield,
618	/// this contains the number of bits in the last unit that can be used for
619	/// an adjacent bitfield if necessary. The unit in question is usually
620	/// a byte, but larger units are used if IsMsStruct.
621	unsigned char UnfilledBitsInLastUnit;
622
623	/// LastBitfieldStorageUnitSize - If IsMsStruct, represents the size of the
624	/// storage unit of the previous field if it was a bitfield.
625	unsigned char LastBitfieldStorageUnitSize;
626
627	/// MaxFieldAlignment - The maximum allowed field alignment. This is set by
628	/// #pragma pack.
629	CharUnits MaxFieldAlignment;
630
631	/// DataSize - The data size of the record being laid out.
632	uint64_t DataSize;
633
634	CharUnits NonVirtualSize;
635	CharUnits NonVirtualAlignment;
636	CharUnits PreferredNVAlignment;
637
638	/// If we've laid out a field but not included its tail padding in Size yet,
639	/// this is the size up to the end of that field.
640	CharUnits PaddedFieldSize;
641
642	/// PrimaryBase - the primary base class (if one exists) of the class
643	/// we're laying out.
644	const CXXRecordDecl *PrimaryBase;
645
646	/// PrimaryBaseIsVirtual - Whether the primary base of the class we're laying
647	/// out is virtual.
648	bool PrimaryBaseIsVirtual;
649
650	/// HasOwnVFPtr - Whether the class provides its own vtable/vftbl
651	/// pointer, as opposed to inheriting one from a primary base class.
652	bool HasOwnVFPtr;
653
654	/// the flag of field offset changing due to packed attribute.
655	bool HasPackedField;
656
657	/// HandledFirstNonOverlappingEmptyField - An auxiliary field used for AIX.
658	/// When there are OverlappingEmptyFields existing in the aggregate, the
659	/// flag shows if the following first non-empty or empty-but-non-overlapping
660	/// field has been handled, if any.
661	bool HandledFirstNonOverlappingEmptyField;
662
663	typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
664
665	/// Bases - base classes and their offsets in the record.
666	BaseOffsetsMapTy Bases;
667
668	// VBases - virtual base classes and their offsets in the record.
669	ASTRecordLayout::VBaseOffsetsMapTy VBases;
670
671	/// IndirectPrimaryBases - Virtual base classes, direct or indirect, that are
672	/// primary base classes for some other direct or indirect base class.
673	CXXIndirectPrimaryBaseSet IndirectPrimaryBases;
674
675	/// FirstNearlyEmptyVBase - The first nearly empty virtual base class in
676	/// inheritance graph order. Used for determining the primary base class.
677	const CXXRecordDecl *FirstNearlyEmptyVBase;
678
679	/// VisitedVirtualBases - A set of all the visited virtual bases, used to
680	/// avoid visiting virtual bases more than once.
681	llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBases;
682
683	/// Valid if UseExternalLayout is true.
684	ExternalLayout External;
685
686	ItaniumRecordLayoutBuilder(const ASTContext &Context,
687	EmptySubobjectMap *EmptySubobjects)
688	: Context(Context), EmptySubobjects(EmptySubobjects), Size(0),
689	Alignment(CharUnits::One()), PreferredAlignment(CharUnits::One()),
690	UnpackedAlignment(CharUnits::One()),
691	UnadjustedAlignment(CharUnits::One()), UseExternalLayout(false),
692	InferAlignment(false), Packed(false), IsUnion(false),
693	IsMac68kAlign(false),
694	IsNaturalAlign(!Context.getTargetInfo().getTriple().isOSAIX()),
695	IsMsStruct(false), UnfilledBitsInLastUnit(0),
696	LastBitfieldStorageUnitSize(0), MaxFieldAlignment(CharUnits::Zero()),
697	DataSize(0), NonVirtualSize(CharUnits::Zero()),
698	NonVirtualAlignment(CharUnits::One()),
699	PreferredNVAlignment(CharUnits::One()),
700	PaddedFieldSize(CharUnits::Zero()), PrimaryBase(nullptr),
701	PrimaryBaseIsVirtual(false), HasOwnVFPtr(false), HasPackedField(false),
702	HandledFirstNonOverlappingEmptyField(false),
703	FirstNearlyEmptyVBase(nullptr) {}
704
705	void Layout(const RecordDecl *D);
706	void Layout(const CXXRecordDecl *D);
707	void Layout(const ObjCInterfaceDecl *D);
708
709	void LayoutFields(const RecordDecl *D);
710	void LayoutField(const FieldDecl *D, bool InsertExtraPadding);
711	void LayoutWideBitField(uint64_t FieldSize, uint64_t StorageUnitSize,
712	bool FieldPacked, const FieldDecl *D);
713	void LayoutBitField(const FieldDecl *D);
714
715	TargetCXXABI getCXXABI() const {
716	return Context.getTargetInfo().getCXXABI();
717	}
718
719	/// BaseSubobjectInfoAllocator - Allocator for BaseSubobjectInfo objects.
720	llvm::SpecificBumpPtrAllocator<BaseSubobjectInfo> BaseSubobjectInfoAllocator;
721
722	typedef llvm::DenseMap<const CXXRecordDecl *, BaseSubobjectInfo *>
723	BaseSubobjectInfoMapTy;
724
725	/// VirtualBaseInfo - Map from all the (direct or indirect) virtual bases
726	/// of the class we're laying out to their base subobject info.
727	BaseSubobjectInfoMapTy VirtualBaseInfo;
728
729	/// NonVirtualBaseInfo - Map from all the direct non-virtual bases of the
730	/// class we're laying out to their base subobject info.
731	BaseSubobjectInfoMapTy NonVirtualBaseInfo;
732
733	/// ComputeBaseSubobjectInfo - Compute the base subobject information for the
734	/// bases of the given class.
735	void ComputeBaseSubobjectInfo(const CXXRecordDecl *RD);
736
737	/// ComputeBaseSubobjectInfo - Compute the base subobject information for a
738	/// single class and all of its base classes.
739	BaseSubobjectInfo *ComputeBaseSubobjectInfo(const CXXRecordDecl *RD,
740	bool IsVirtual,
741	BaseSubobjectInfo *Derived);
742
743	/// DeterminePrimaryBase - Determine the primary base of the given class.
744	void DeterminePrimaryBase(const CXXRecordDecl *RD);
745
746	void SelectPrimaryVBase(const CXXRecordDecl *RD);
747
748	void EnsureVTablePointerAlignment(CharUnits UnpackedBaseAlign);
749
750	/// LayoutNonVirtualBases - Determines the primary base class (if any) and
751	/// lays it out. Will then proceed to lay out all non-virtual base clasess.
752	void LayoutNonVirtualBases(const CXXRecordDecl *RD);
753
754	/// LayoutNonVirtualBase - Lays out a single non-virtual base.
755	void LayoutNonVirtualBase(const BaseSubobjectInfo *Base);
756
757	void AddPrimaryVirtualBaseOffsets(const BaseSubobjectInfo *Info,
758	CharUnits Offset);
759
760	/// LayoutVirtualBases - Lays out all the virtual bases.
761	void LayoutVirtualBases(const CXXRecordDecl *RD,
762	const CXXRecordDecl *MostDerivedClass);
763
764	/// LayoutVirtualBase - Lays out a single virtual base.
765	void LayoutVirtualBase(const BaseSubobjectInfo *Base);
766
767	/// LayoutBase - Will lay out a base and return the offset where it was
768	/// placed, in chars.
769	CharUnits LayoutBase(const BaseSubobjectInfo *Base);
770
771	/// InitializeLayout - Initialize record layout for the given record decl.
772	void InitializeLayout(const Decl *D);
773
774	/// FinishLayout - Finalize record layout. Adjust record size based on the
775	/// alignment.
776	void FinishLayout(const NamedDecl *D);
777
778	void UpdateAlignment(CharUnits NewAlignment, CharUnits UnpackedNewAlignment,
779	CharUnits PreferredAlignment);
780	void UpdateAlignment(CharUnits NewAlignment, CharUnits UnpackedNewAlignment) {
781	UpdateAlignment(NewAlignment, UnpackedNewAlignment, PreferredAlignment: NewAlignment);
782	}
783	void UpdateAlignment(CharUnits NewAlignment) {
784	UpdateAlignment(NewAlignment, UnpackedNewAlignment: NewAlignment, PreferredAlignment: NewAlignment);
785	}
786
787	/// Retrieve the externally-supplied field offset for the given
788	/// field.
789	///
790	/// \param Field The field whose offset is being queried.
791	/// \param ComputedOffset The offset that we've computed for this field.
792	uint64_t updateExternalFieldOffset(const FieldDecl *Field,
793	uint64_t ComputedOffset);
794
795	void CheckFieldPadding(uint64_t Offset, uint64_t UnpaddedOffset,
796	uint64_t UnpackedOffset, unsigned UnpackedAlign,
797	bool isPacked, const FieldDecl *D);
798
799	DiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID);
800
801	CharUnits getSize() const {
802	assert(Size % Context.getCharWidth() == 0);
803	return Context.toCharUnitsFromBits(BitSize: Size);
804	}
805	uint64_t getSizeInBits() const { return Size; }
806
807	void setSize(CharUnits NewSize) { Size = Context.toBits(CharSize: NewSize); }
808	void setSize(uint64_t NewSize) { Size = NewSize; }
809
810	CharUnits getAlignment() const { return Alignment; }
811
812	CharUnits getDataSize() const {
813	assert(DataSize % Context.getCharWidth() == 0);
814	return Context.toCharUnitsFromBits(BitSize: DataSize);
815	}
816	uint64_t getDataSizeInBits() const { return DataSize; }
817
818	void setDataSize(CharUnits NewSize) { DataSize = Context.toBits(CharSize: NewSize); }
819	void setDataSize(uint64_t NewSize) { DataSize = NewSize; }
820
821	ItaniumRecordLayoutBuilder(const ItaniumRecordLayoutBuilder &) = delete;
822	void operator=(const ItaniumRecordLayoutBuilder &) = delete;
823	};
824	} // end anonymous namespace
825
826	void ItaniumRecordLayoutBuilder::SelectPrimaryVBase(const CXXRecordDecl *RD) {
827	for (const auto &I : RD->bases()) {
828	assert(!I.getType()->isDependentType() &&
829	"Cannot layout class with dependent bases.");
830
831	const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
832
833	// Check if this is a nearly empty virtual base.
834	if (I.isVirtual() && Context.isNearlyEmpty(RD: Base)) {
835	// If it's not an indirect primary base, then we've found our primary
836	// base.
837	if (!IndirectPrimaryBases.count(Ptr: Base)) {
838	PrimaryBase = Base;
839	PrimaryBaseIsVirtual = true;
840	return;
841	}
842
843	// Is this the first nearly empty virtual base?
844	if (!FirstNearlyEmptyVBase)
845	FirstNearlyEmptyVBase = Base;
846	}
847
848	SelectPrimaryVBase(RD: Base);
849	if (PrimaryBase)
850	return;
851	}
852	}
853
854	/// DeterminePrimaryBase - Determine the primary base of the given class.
855	void ItaniumRecordLayoutBuilder::DeterminePrimaryBase(const CXXRecordDecl *RD) {
856	// If the class isn't dynamic, it won't have a primary base.
857	if (!RD->isDynamicClass())
858	return;
859
860	// Compute all the primary virtual bases for all of our direct and
861	// indirect bases, and record all their primary virtual base classes.
862	RD->getIndirectPrimaryBases(Bases&: IndirectPrimaryBases);
863
864	// If the record has a dynamic base class, attempt to choose a primary base
865	// class. It is the first (in direct base class order) non-virtual dynamic
866	// base class, if one exists.
867	for (const auto &I : RD->bases()) {
868	// Ignore virtual bases.
869	if (I.isVirtual())
870	continue;
871
872	const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
873
874	if (Base->isDynamicClass()) {
875	// We found it.
876	PrimaryBase = Base;
877	PrimaryBaseIsVirtual = false;
878	return;
879	}
880	}
881
882	// Under the Itanium ABI, if there is no non-virtual primary base class,
883	// try to compute the primary virtual base. The primary virtual base is
884	// the first nearly empty virtual base that is not an indirect primary
885	// virtual base class, if one exists.
886	if (RD->getNumVBases() != 0) {
887	SelectPrimaryVBase(RD);
888	if (PrimaryBase)
889	return;
890	}
891
892	// Otherwise, it is the first indirect primary base class, if one exists.
893	if (FirstNearlyEmptyVBase) {
894	PrimaryBase = FirstNearlyEmptyVBase;
895	PrimaryBaseIsVirtual = true;
896	return;
897	}
898
899	assert(!PrimaryBase && "Should not get here with a primary base!");
900	}
901
902	BaseSubobjectInfo *ItaniumRecordLayoutBuilder::ComputeBaseSubobjectInfo(
903	const CXXRecordDecl *RD, bool IsVirtual, BaseSubobjectInfo *Derived) {
904	BaseSubobjectInfo *Info;
905
906	if (IsVirtual) {
907	// Check if we already have info about this virtual base.
908	BaseSubobjectInfo *&InfoSlot = VirtualBaseInfo[RD];
909	if (InfoSlot) {
910	assert(InfoSlot->Class == RD && "Wrong class for virtual base info!");
911	return InfoSlot;
912	}
913
914	// We don't, create it.
915	InfoSlot = new (BaseSubobjectInfoAllocator.Allocate()) BaseSubobjectInfo;
916	Info = InfoSlot;
917	} else {
918	Info = new (BaseSubobjectInfoAllocator.Allocate()) BaseSubobjectInfo;
919	}
920
921	Info->Class = RD;
922	Info->IsVirtual = IsVirtual;
923	Info->Derived = nullptr;
924	Info->PrimaryVirtualBaseInfo = nullptr;
925
926	const CXXRecordDecl *PrimaryVirtualBase = nullptr;
927	BaseSubobjectInfo *PrimaryVirtualBaseInfo = nullptr;
928
929	// Check if this base has a primary virtual base.
930	if (RD->getNumVBases()) {
931	const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
932	if (Layout.isPrimaryBaseVirtual()) {
933	// This base does have a primary virtual base.
934	PrimaryVirtualBase = Layout.getPrimaryBase();
935	assert(PrimaryVirtualBase && "Didn't have a primary virtual base!");
936
937	// Now check if we have base subobject info about this primary base.
938	PrimaryVirtualBaseInfo = VirtualBaseInfo.lookup(Val: PrimaryVirtualBase);
939
940	if (PrimaryVirtualBaseInfo) {
941	if (PrimaryVirtualBaseInfo->Derived) {
942	// We did have info about this primary base, and it turns out that it
943	// has already been claimed as a primary virtual base for another
944	// base.
945	PrimaryVirtualBase = nullptr;
946	} else {
947	// We can claim this base as our primary base.
948	Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
949	PrimaryVirtualBaseInfo->Derived = Info;
950	}
951	}
952	}
953	}
954
955	// Now go through all direct bases.
956	for (const auto &I : RD->bases()) {
957	bool IsVirtual = I.isVirtual();
958
959	const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
960
961	Info->Bases.push_back(Elt: ComputeBaseSubobjectInfo(RD: BaseDecl, IsVirtual, Derived: Info));
962	}
963
964	if (PrimaryVirtualBase && !PrimaryVirtualBaseInfo) {
965	// Traversing the bases must have created the base info for our primary
966	// virtual base.
967	PrimaryVirtualBaseInfo = VirtualBaseInfo.lookup(Val: PrimaryVirtualBase);
968	assert(PrimaryVirtualBaseInfo &&
969	"Did not create a primary virtual base!");
970
971	// Claim the primary virtual base as our primary virtual base.
972	Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
973	PrimaryVirtualBaseInfo->Derived = Info;
974	}
975
976	return Info;
977	}
978
979	void ItaniumRecordLayoutBuilder::ComputeBaseSubobjectInfo(
980	const CXXRecordDecl *RD) {
981	for (const auto &I : RD->bases()) {
982	bool IsVirtual = I.isVirtual();
983
984	const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
985
986	// Compute the base subobject info for this base.
987	BaseSubobjectInfo *Info = ComputeBaseSubobjectInfo(RD: BaseDecl, IsVirtual,
988	Derived: nullptr);
989
990	if (IsVirtual) {
991	// ComputeBaseInfo has already added this base for us.
992	assert(VirtualBaseInfo.count(BaseDecl) &&
993	"Did not add virtual base!");
994	} else {
995	// Add the base info to the map of non-virtual bases.
996	assert(!NonVirtualBaseInfo.count(BaseDecl) &&
997	"Non-virtual base already exists!");
998	NonVirtualBaseInfo.insert(KV: std::make_pair(x&: BaseDecl, y&: Info));
999	}
1000	}
1001	}
1002
1003	void ItaniumRecordLayoutBuilder::EnsureVTablePointerAlignment(
1004	CharUnits UnpackedBaseAlign) {
1005	CharUnits BaseAlign = Packed ? CharUnits::One() : UnpackedBaseAlign;
1006
1007	// The maximum field alignment overrides base align.
1008	if (!MaxFieldAlignment.isZero()) {
1009	BaseAlign = std::min(a: BaseAlign, b: MaxFieldAlignment);
1010	UnpackedBaseAlign = std::min(a: UnpackedBaseAlign, b: MaxFieldAlignment);
1011	}
1012
1013	// Round up the current record size to pointer alignment.
1014	setSize(getSize().alignTo(Align: BaseAlign));
1015
1016	// Update the alignment.
1017	UpdateAlignment(NewAlignment: BaseAlign, UnpackedNewAlignment: UnpackedBaseAlign, PreferredAlignment: BaseAlign);
1018	}
1019
1020	void ItaniumRecordLayoutBuilder::LayoutNonVirtualBases(
1021	const CXXRecordDecl *RD) {
1022	// Then, determine the primary base class.
1023	DeterminePrimaryBase(RD);
1024
1025	// Compute base subobject info.
1026	ComputeBaseSubobjectInfo(RD);
1027
1028	// If we have a primary base class, lay it out.
1029	if (PrimaryBase) {
1030	if (PrimaryBaseIsVirtual) {
1031	// If the primary virtual base was a primary virtual base of some other
1032	// base class we'll have to steal it.
1033	BaseSubobjectInfo *PrimaryBaseInfo = VirtualBaseInfo.lookup(Val: PrimaryBase);
1034	PrimaryBaseInfo->Derived = nullptr;
1035
1036	// We have a virtual primary base, insert it as an indirect primary base.
1037	IndirectPrimaryBases.insert(Ptr: PrimaryBase);
1038
1039	assert(!VisitedVirtualBases.count(PrimaryBase) &&
1040	"vbase already visited!");
1041	VisitedVirtualBases.insert(Ptr: PrimaryBase);
1042
1043	LayoutVirtualBase(Base: PrimaryBaseInfo);
1044	} else {
1045	BaseSubobjectInfo *PrimaryBaseInfo =
1046	NonVirtualBaseInfo.lookup(Val: PrimaryBase);
1047	assert(PrimaryBaseInfo &&
1048	"Did not find base info for non-virtual primary base!");
1049
1050	LayoutNonVirtualBase(Base: PrimaryBaseInfo);
1051	}
1052
1053	// If this class needs a vtable/vf-table and didn't get one from a
1054	// primary base, add it in now.
1055	} else if (RD->isDynamicClass()) {
1056	assert(DataSize == 0 && "Vtable pointer must be at offset zero!");
1057	CharUnits PtrWidth = Context.toCharUnitsFromBits(
1058	BitSize: Context.getTargetInfo().getPointerWidth(AddrSpace: LangAS::Default));
1059	CharUnits PtrAlign = Context.toCharUnitsFromBits(
1060	BitSize: Context.getTargetInfo().getPointerAlign(AddrSpace: LangAS::Default));
1061	EnsureVTablePointerAlignment(UnpackedBaseAlign: PtrAlign);
1062	HasOwnVFPtr = true;
1063
1064	assert(!IsUnion && "Unions cannot be dynamic classes.");
1065	HandledFirstNonOverlappingEmptyField = true;
1066
1067	setSize(getSize() + PtrWidth);
1068	setDataSize(getSize());
1069	}
1070
1071	// Now lay out the non-virtual bases.
1072	for (const auto &I : RD->bases()) {
1073
1074	// Ignore virtual bases.
1075	if (I.isVirtual())
1076	continue;
1077
1078	const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
1079
1080	// Skip the primary base, because we've already laid it out. The
1081	// !PrimaryBaseIsVirtual check is required because we might have a
1082	// non-virtual base of the same type as a primary virtual base.
1083	if (BaseDecl == PrimaryBase && !PrimaryBaseIsVirtual)
1084	continue;
1085
1086	// Lay out the base.
1087	BaseSubobjectInfo *BaseInfo = NonVirtualBaseInfo.lookup(Val: BaseDecl);
1088	assert(BaseInfo && "Did not find base info for non-virtual base!");
1089
1090	LayoutNonVirtualBase(Base: BaseInfo);
1091	}
1092	}
1093
1094	void ItaniumRecordLayoutBuilder::LayoutNonVirtualBase(
1095	const BaseSubobjectInfo *Base) {
1096	// Layout the base.
1097	CharUnits Offset = LayoutBase(Base);
1098
1099	// Add its base class offset.
1100	assert(!Bases.count(Base->Class) && "base offset already exists!");
1101	Bases.insert(KV: std::make_pair(x: Base->Class, y&: Offset));
1102
1103	AddPrimaryVirtualBaseOffsets(Info: Base, Offset);
1104	}
1105
1106	void ItaniumRecordLayoutBuilder::AddPrimaryVirtualBaseOffsets(
1107	const BaseSubobjectInfo *Info, CharUnits Offset) {
1108	// This base isn't interesting, it has no virtual bases.
1109	if (!Info->Class->getNumVBases())
1110	return;
1111
1112	// First, check if we have a virtual primary base to add offsets for.
1113	if (Info->PrimaryVirtualBaseInfo) {
1114	assert(Info->PrimaryVirtualBaseInfo->IsVirtual &&
1115	"Primary virtual base is not virtual!");
1116	if (Info->PrimaryVirtualBaseInfo->Derived == Info) {
1117	// Add the offset.
1118	assert(!VBases.count(Info->PrimaryVirtualBaseInfo->Class) &&
1119	"primary vbase offset already exists!");
1120	VBases.insert(KV: std::make_pair(x&: Info->PrimaryVirtualBaseInfo->Class,
1121	y: ASTRecordLayout::VBaseInfo(Offset, false)));
1122
1123	// Traverse the primary virtual base.
1124	AddPrimaryVirtualBaseOffsets(Info: Info->PrimaryVirtualBaseInfo, Offset);
1125	}
1126	}
1127
1128	// Now go through all direct non-virtual bases.
1129	const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
1130	for (const BaseSubobjectInfo *Base : Info->Bases) {
1131	if (Base->IsVirtual)
1132	continue;
1133
1134	CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base: Base->Class);
1135	AddPrimaryVirtualBaseOffsets(Info: Base, Offset: BaseOffset);
1136	}
1137	}
1138
1139	void ItaniumRecordLayoutBuilder::LayoutVirtualBases(
1140	const CXXRecordDecl *RD, const CXXRecordDecl *MostDerivedClass) {
1141	const CXXRecordDecl *PrimaryBase;
1142	bool PrimaryBaseIsVirtual;
1143
1144	if (MostDerivedClass == RD) {
1145	PrimaryBase = this->PrimaryBase;
1146	PrimaryBaseIsVirtual = this->PrimaryBaseIsVirtual;
1147	} else {
1148	const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1149	PrimaryBase = Layout.getPrimaryBase();
1150	PrimaryBaseIsVirtual = Layout.isPrimaryBaseVirtual();
1151	}
1152
1153	for (const CXXBaseSpecifier &Base : RD->bases()) {
1154	assert(!Base.getType()->isDependentType() &&
1155	"Cannot layout class with dependent bases.");
1156
1157	const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1158
1159	if (Base.isVirtual()) {
1160	if (PrimaryBase != BaseDecl || !PrimaryBaseIsVirtual) {
1161	bool IndirectPrimaryBase = IndirectPrimaryBases.count(Ptr: BaseDecl);
1162
1163	// Only lay out the virtual base if it's not an indirect primary base.
1164	if (!IndirectPrimaryBase) {
1165	// Only visit virtual bases once.
1166	if (!VisitedVirtualBases.insert(Ptr: BaseDecl).second)
1167	continue;
1168
1169	const BaseSubobjectInfo *BaseInfo = VirtualBaseInfo.lookup(Val: BaseDecl);
1170	assert(BaseInfo && "Did not find virtual base info!");
1171	LayoutVirtualBase(Base: BaseInfo);
1172	}
1173	}
1174	}
1175
1176	if (!BaseDecl->getNumVBases()) {
1177	// This base isn't interesting since it doesn't have any virtual bases.
1178	continue;
1179	}
1180
1181	LayoutVirtualBases(RD: BaseDecl, MostDerivedClass);
1182	}
1183	}
1184
1185	void ItaniumRecordLayoutBuilder::LayoutVirtualBase(
1186	const BaseSubobjectInfo *Base) {
1187	assert(!Base->Derived && "Trying to lay out a primary virtual base!");
1188
1189	// Layout the base.
1190	CharUnits Offset = LayoutBase(Base);
1191
1192	// Add its base class offset.
1193	assert(!VBases.count(Base->Class) && "vbase offset already exists!");
1194	VBases.insert(KV: std::make_pair(x: Base->Class,
1195	y: ASTRecordLayout::VBaseInfo(Offset, false)));
1196
1197	AddPrimaryVirtualBaseOffsets(Info: Base, Offset);
1198	}
1199
1200	CharUnits
1201	ItaniumRecordLayoutBuilder::LayoutBase(const BaseSubobjectInfo *Base) {
1202	assert(!IsUnion && "Unions cannot have base classes.");
1203
1204	const ASTRecordLayout &Layout = Context.getASTRecordLayout(Base->Class);
1205	CharUnits Offset;
1206
1207	// Query the external layout to see if it provides an offset.
1208	bool HasExternalLayout = false;
1209	if (UseExternalLayout) {
1210	if (Base->IsVirtual)
1211	HasExternalLayout = External.getExternalVBaseOffset(RD: Base->Class, BaseOffset&: Offset);
1212	else
1213	HasExternalLayout = External.getExternalNVBaseOffset(RD: Base->Class, BaseOffset&: Offset);
1214	}
1215
1216	auto getBaseOrPreferredBaseAlignFromUnpacked = [&](CharUnits UnpackedAlign) {
1217	// Clang <= 6 incorrectly applied the 'packed' attribute to base classes.
1218	// Per GCC's documentation, it only applies to non-static data members.
1219	return (Packed && ((Context.getLangOpts().getClangABICompat() <=
1220	LangOptions::ClangABI::Ver6) ||
1221	Context.getTargetInfo().getTriple().isPS() ||
1222	Context.getTargetInfo().getTriple().isOSAIX()))
1223	? CharUnits::One()
1224	: UnpackedAlign;
1225	};
1226
1227	CharUnits UnpackedBaseAlign = Layout.getNonVirtualAlignment();
1228	CharUnits UnpackedPreferredBaseAlign = Layout.getPreferredNVAlignment();
1229	CharUnits BaseAlign =
1230	getBaseOrPreferredBaseAlignFromUnpacked(UnpackedBaseAlign);
1231	CharUnits PreferredBaseAlign =
1232	getBaseOrPreferredBaseAlignFromUnpacked(UnpackedPreferredBaseAlign);
1233
1234	const bool DefaultsToAIXPowerAlignment =
1235	Context.getTargetInfo().defaultsToAIXPowerAlignment();
1236	if (DefaultsToAIXPowerAlignment) {
1237	// AIX `power` alignment does not apply the preferred alignment for
1238	// non-union classes if the source of the alignment (the current base in
1239	// this context) follows introduction of the first subobject with
1240	// exclusively allocated space or zero-extent array.
1241	if (!Base->Class->isEmpty() && !HandledFirstNonOverlappingEmptyField) {
1242	// By handling a base class that is not empty, we're handling the
1243	// "first (inherited) member".
1244	HandledFirstNonOverlappingEmptyField = true;
1245	} else if (!IsNaturalAlign) {
1246	UnpackedPreferredBaseAlign = UnpackedBaseAlign;
1247	PreferredBaseAlign = BaseAlign;
1248	}
1249	}
1250
1251	CharUnits UnpackedAlignTo = !DefaultsToAIXPowerAlignment
1252	? UnpackedBaseAlign
1253	: UnpackedPreferredBaseAlign;
1254	// If we have an empty base class, try to place it at offset 0.
1255	if (Base->Class->isEmpty() &&
1256	(!HasExternalLayout || Offset == CharUnits::Zero()) &&
1257	EmptySubobjects->CanPlaceBaseAtOffset(Info: Base, Offset: CharUnits::Zero())) {
1258	setSize(std::max(a: getSize(), b: Layout.getSize()));
1259	// On PS4/PS5, don't update the alignment, to preserve compatibility.
1260	if (!Context.getTargetInfo().getTriple().isPS())
1261	UpdateAlignment(NewAlignment: BaseAlign, UnpackedNewAlignment: UnpackedAlignTo, PreferredAlignment: PreferredBaseAlign);
1262
1263	return CharUnits::Zero();
1264	}
1265
1266	// The maximum field alignment overrides the base align/(AIX-only) preferred
1267	// base align.
1268	if (!MaxFieldAlignment.isZero()) {
1269	BaseAlign = std::min(a: BaseAlign, b: MaxFieldAlignment);
1270	PreferredBaseAlign = std::min(a: PreferredBaseAlign, b: MaxFieldAlignment);
1271	UnpackedAlignTo = std::min(a: UnpackedAlignTo, b: MaxFieldAlignment);
1272	}
1273
1274	CharUnits AlignTo =
1275	!DefaultsToAIXPowerAlignment ? BaseAlign : PreferredBaseAlign;
1276	if (!HasExternalLayout) {
1277	// Round up the current record size to the base's alignment boundary.
1278	Offset = getDataSize().alignTo(Align: AlignTo);
1279
1280	// Try to place the base.
1281	while (!EmptySubobjects->CanPlaceBaseAtOffset(Info: Base, Offset))
1282	Offset += AlignTo;
1283	} else {
1284	bool Allowed = EmptySubobjects->CanPlaceBaseAtOffset(Info: Base, Offset);
1285	(void)Allowed;
1286	assert(Allowed && "Base subobject externally placed at overlapping offset");
1287
1288	if (InferAlignment && Offset < getDataSize().alignTo(Align: AlignTo)) {
1289	// The externally-supplied base offset is before the base offset we
1290	// computed. Assume that the structure is packed.
1291	Alignment = CharUnits::One();
1292	InferAlignment = false;
1293	}
1294	}
1295
1296	if (!Base->Class->isEmpty()) {
1297	// Update the data size.
1298	setDataSize(Offset + Layout.getNonVirtualSize());
1299
1300	setSize(std::max(a: getSize(), b: getDataSize()));
1301	} else
1302	setSize(std::max(a: getSize(), b: Offset + Layout.getSize()));
1303
1304	// Remember max struct/class alignment.
1305	UnadjustedAlignment = std::max(a: UnadjustedAlignment, b: BaseAlign);
1306	UpdateAlignment(NewAlignment: BaseAlign, UnpackedNewAlignment: UnpackedAlignTo, PreferredAlignment: PreferredBaseAlign);
1307
1308	return Offset;
1309	}
1310
1311	void ItaniumRecordLayoutBuilder::InitializeLayout(const Decl *D) {
1312	if (const RecordDecl *RD = dyn_cast<RecordDecl>(Val: D)) {
1313	IsUnion = RD->isUnion();
1314	IsMsStruct = RD->isMsStruct(C: Context);
1315	}
1316
1317	Packed = D->hasAttr<PackedAttr>();
1318
1319	// Honor the default struct packing maximum alignment flag.
1320	if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct) {
1321	MaxFieldAlignment = CharUnits::fromQuantity(Quantity: DefaultMaxFieldAlignment);
1322	}
1323
1324	// mac68k alignment supersedes maximum field alignment and attribute aligned,
1325	// and forces all structures to have 2-byte alignment. The IBM docs on it
1326	// allude to additional (more complicated) semantics, especially with regard
1327	// to bit-fields, but gcc appears not to follow that.
1328	if (D->hasAttr<AlignMac68kAttr>()) {
1329	assert(
1330	!D->hasAttr<AlignNaturalAttr>() &&
1331	"Having both mac68k and natural alignment on a decl is not allowed.");
1332	IsMac68kAlign = true;
1333	MaxFieldAlignment = CharUnits::fromQuantity(Quantity: 2);
1334	Alignment = CharUnits::fromQuantity(Quantity: 2);
1335	PreferredAlignment = CharUnits::fromQuantity(Quantity: 2);
1336	} else {
1337	if (D->hasAttr<AlignNaturalAttr>())
1338	IsNaturalAlign = true;
1339
1340	if (const MaxFieldAlignmentAttr *MFAA = D->getAttr<MaxFieldAlignmentAttr>())
1341	MaxFieldAlignment = Context.toCharUnitsFromBits(BitSize: MFAA->getAlignment());
1342
1343	if (unsigned MaxAlign = D->getMaxAlignment())
1344	UpdateAlignment(NewAlignment: Context.toCharUnitsFromBits(BitSize: MaxAlign));
1345	}
1346
1347	HandledFirstNonOverlappingEmptyField =
1348	!Context.getTargetInfo().defaultsToAIXPowerAlignment() || IsNaturalAlign;
1349
1350	// If there is an external AST source, ask it for the various offsets.
1351	if (const RecordDecl *RD = dyn_cast<RecordDecl>(Val: D))
1352	if (ExternalASTSource *Source = Context.getExternalSource()) {
1353	UseExternalLayout = Source->layoutRecordType(
1354	Record: RD, Size&: External.Size, Alignment&: External.Align, FieldOffsets&: External.FieldOffsets,
1355	BaseOffsets&: External.BaseOffsets, VirtualBaseOffsets&: External.VirtualBaseOffsets);
1356
1357	// Update based on external alignment.
1358	if (UseExternalLayout) {
1359	if (External.Align > 0) {
1360	Alignment = Context.toCharUnitsFromBits(BitSize: External.Align);
1361	PreferredAlignment = Context.toCharUnitsFromBits(BitSize: External.Align);
1362	} else {
1363	// The external source didn't have alignment information; infer it.
1364	InferAlignment = true;
1365	}
1366	}
1367	}
1368	}
1369
1370	void ItaniumRecordLayoutBuilder::Layout(const RecordDecl *D) {
1371	InitializeLayout(D);
1372	LayoutFields(D);
1373
1374	// Finally, round the size of the total struct up to the alignment of the
1375	// struct itself.
1376	FinishLayout(D);
1377	}
1378
1379	void ItaniumRecordLayoutBuilder::Layout(const CXXRecordDecl *RD) {
1380	InitializeLayout(RD);
1381
1382	// Lay out the vtable and the non-virtual bases.
1383	LayoutNonVirtualBases(RD);
1384
1385	LayoutFields(RD);
1386
1387	NonVirtualSize = Context.toCharUnitsFromBits(
1388	BitSize: llvm::alignTo(Value: getSizeInBits(), Align: Context.getTargetInfo().getCharAlign()));
1389	NonVirtualAlignment = Alignment;
1390	PreferredNVAlignment = PreferredAlignment;
1391
1392	// Lay out the virtual bases and add the primary virtual base offsets.
1393	LayoutVirtualBases(RD, MostDerivedClass: RD);
1394
1395	// Finally, round the size of the total struct up to the alignment
1396	// of the struct itself.
1397	FinishLayout(RD);
1398
1399	#ifndef NDEBUG
1400	// Check that we have base offsets for all bases.
1401	for (const CXXBaseSpecifier &Base : RD->bases()) {
1402	if (Base.isVirtual())
1403	continue;
1404
1405	const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1406
1407	assert(Bases.count(BaseDecl) && "Did not find base offset!");
1408	}
1409
1410	// And all virtual bases.
1411	for (const CXXBaseSpecifier &Base : RD->vbases()) {
1412	const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1413
1414	assert(VBases.count(BaseDecl) && "Did not find base offset!");
1415	}
1416	#endif
1417	}
1418
1419	void ItaniumRecordLayoutBuilder::Layout(const ObjCInterfaceDecl *D) {
1420	if (ObjCInterfaceDecl *SD = D->getSuperClass()) {
1421	const ASTRecordLayout &SL = Context.getASTObjCInterfaceLayout(D: SD);
1422
1423	UpdateAlignment(NewAlignment: SL.getAlignment());
1424
1425	// We start laying out ivars not at the end of the superclass
1426	// structure, but at the next byte following the last field.
1427	setDataSize(SL.getDataSize());
1428	setSize(getDataSize());
1429	}
1430
1431	InitializeLayout(D);
1432	// Layout each ivar sequentially.
1433	for (const ObjCIvarDecl *IVD = D->all_declared_ivar_begin(); IVD;
1434	IVD = IVD->getNextIvar())
1435	LayoutField(IVD, false);
1436
1437	// Finally, round the size of the total struct up to the alignment of the
1438	// struct itself.
1439	FinishLayout(D);
1440	}
1441
1442	void ItaniumRecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
1443	// Layout each field, for now, just sequentially, respecting alignment. In
1444	// the future, this will need to be tweakable by targets.
1445	bool InsertExtraPadding = D->mayInsertExtraPadding(/*EmitRemark=*/true);
1446	bool HasFlexibleArrayMember = D->hasFlexibleArrayMember();
1447	for (auto I = D->field_begin(), End = D->field_end(); I != End; ++I) {
1448	LayoutField(D: *I, InsertExtraPadding: InsertExtraPadding &&
1449	(std::next(x: I) != End || !HasFlexibleArrayMember));
1450	}
1451	}
1452
1453	// Rounds the specified size to have it a multiple of the char size.
1454	static uint64_t
1455	roundUpSizeToCharAlignment(uint64_t Size,
1456	const ASTContext &Context) {
1457	uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
1458	return llvm::alignTo(Value: Size, Align: CharAlignment);
1459	}
1460
1461	void ItaniumRecordLayoutBuilder::LayoutWideBitField(uint64_t FieldSize,
1462	uint64_t StorageUnitSize,
1463	bool FieldPacked,
1464	const FieldDecl *D) {
1465	assert(Context.getLangOpts().CPlusPlus &&
1466	"Can only have wide bit-fields in C++!");
1467
1468	// Itanium C++ ABI 2.4:
1469	// If sizeof(T)*8 < n, let T' be the largest integral POD type with
1470	// sizeof(T')*8 <= n.
1471
1472	QualType IntegralPODTypes[] = {
1473	Context.UnsignedCharTy, Context.UnsignedShortTy,
1474	Context.UnsignedIntTy, Context.UnsignedLongTy,
1475	Context.UnsignedLongLongTy, Context.UnsignedInt128Ty,
1476	};
1477
1478	QualType Type;
1479	uint64_t MaxSize =
1480	Context.getTargetInfo().getLargestOverSizedBitfieldContainer();
1481	for (const QualType &QT : IntegralPODTypes) {
1482	uint64_t Size = Context.getTypeSize(QT);
1483
1484	if (Size > FieldSize || Size > MaxSize)
1485	break;
1486
1487	Type = QT;
1488	}
1489	assert(!Type.isNull() && "Did not find a type!");
1490
1491	CharUnits TypeAlign = Context.getTypeAlignInChars(T: Type);
1492
1493	// We're not going to use any of the unfilled bits in the last byte.
1494	UnfilledBitsInLastUnit = 0;
1495	LastBitfieldStorageUnitSize = 0;
1496
1497	uint64_t FieldOffset;
1498	uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;
1499
1500	if (IsUnion) {
1501	uint64_t RoundedFieldSize = roundUpSizeToCharAlignment(Size: FieldSize,
1502	Context);
1503	setDataSize(std::max(a: getDataSizeInBits(), b: RoundedFieldSize));
1504	FieldOffset = 0;
1505	} else {
1506	// The bitfield is allocated starting at the next offset aligned
1507	// appropriately for T', with length n bits.
1508	FieldOffset = llvm::alignTo(Value: getDataSizeInBits(), Align: Context.toBits(CharSize: TypeAlign));
1509
1510	uint64_t NewSizeInBits = FieldOffset + FieldSize;
1511
1512	setDataSize(
1513	llvm::alignTo(Value: NewSizeInBits, Align: Context.getTargetInfo().getCharAlign()));
1514	UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;
1515	}
1516
1517	// Place this field at the current location.
1518	FieldOffsets.push_back(Elt: FieldOffset);
1519
1520	CheckFieldPadding(Offset: FieldOffset, UnpaddedOffset: UnpaddedFieldOffset, UnpackedOffset: FieldOffset,
1521	UnpackedAlign: Context.toBits(CharSize: TypeAlign), isPacked: FieldPacked, D);
1522
1523	// Update the size.
1524	setSize(std::max(a: getSizeInBits(), b: getDataSizeInBits()));
1525
1526	// Remember max struct/class alignment.
1527	UnadjustedAlignment = std::max(a: UnadjustedAlignment, b: TypeAlign);
1528	UpdateAlignment(NewAlignment: TypeAlign);
1529	}
1530
1531	static bool isAIXLayout(const ASTContext &Context) {
1532	return Context.getTargetInfo().getTriple().getOS() == llvm::Triple::AIX;
1533	}
1534
1535	void ItaniumRecordLayoutBuilder::LayoutBitField(const FieldDecl *D) {
1536	bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
1537	uint64_t FieldSize = D->getBitWidthValue();
1538	TypeInfo FieldInfo = Context.getTypeInfo(D->getType());
1539	uint64_t StorageUnitSize = FieldInfo.Width;
1540	unsigned FieldAlign = FieldInfo.Align;
1541	bool AlignIsRequired = FieldInfo.isAlignRequired();
1542	unsigned char PaddingInLastUnit = 0;
1543
1544	// UnfilledBitsInLastUnit is the difference between the end of the
1545	// last allocated bitfield (i.e. the first bit offset available for
1546	// bitfields) and the end of the current data size in bits (i.e. the
1547	// first bit offset available for non-bitfields). The current data
1548	// size in bits is always a multiple of the char size; additionally,
1549	// for ms_struct records it's also a multiple of the
1550	// LastBitfieldStorageUnitSize (if set).
1551
1552	// The struct-layout algorithm is dictated by the platform ABI,
1553	// which in principle could use almost any rules it likes. In
1554	// practice, UNIXy targets tend to inherit the algorithm described
1555	// in the System V generic ABI. The basic bitfield layout rule in
1556	// System V is to place bitfields at the next available bit offset
1557	// where the entire bitfield would fit in an aligned storage unit of
1558	// the declared type; it's okay if an earlier or later non-bitfield
1559	// is allocated in the same storage unit. However, some targets
1560	// (those that !useBitFieldTypeAlignment(), e.g. ARM APCS) don't
1561	// require this storage unit to be aligned, and therefore always put
1562	// the bitfield at the next available bit offset.
1563
1564	// ms_struct basically requests a complete replacement of the
1565	// platform ABI's struct-layout algorithm, with the high-level goal
1566	// of duplicating MSVC's layout. For non-bitfields, this follows
1567	// the standard algorithm. The basic bitfield layout rule is to
1568	// allocate an entire unit of the bitfield's declared type
1569	// (e.g. 'unsigned long'), then parcel it up among successive
1570	// bitfields whose declared types have the same size, making a new
1571	// unit as soon as the last can no longer store the whole value.
1572	// Since it completely replaces the platform ABI's algorithm,
1573	// settings like !useBitFieldTypeAlignment() do not apply.
1574
1575	// A zero-width bitfield forces the use of a new storage unit for
1576	// later bitfields. In general, this occurs by rounding up the
1577	// current size of the struct as if the algorithm were about to
1578	// place a non-bitfield of the field's formal type. Usually this
1579	// does not change the alignment of the struct itself, but it does
1580	// on some targets (those that useZeroLengthBitfieldAlignment(),
1581	// e.g. ARM). In ms_struct layout, zero-width bitfields are
1582	// ignored unless they follow a non-zero-width bitfield.
1583
1584	// A field alignment restriction (e.g. from #pragma pack) or
1585	// specification (e.g. from __attribute__((aligned))) changes the
1586	// formal alignment of the field. For System V, this alters the
1587	// required alignment of the notional storage unit that must contain
1588	// the bitfield. For ms_struct, this only affects the placement of
1589	// new storage units. In both cases, the effect of #pragma pack is
1590	// ignored on zero-width bitfields.
1591
1592	// On System V, a packed field (e.g. from #pragma pack or
1593	// __attribute__((packed))) always uses the next available bit
1594	// offset.
1595
1596	// In an ms_struct struct, the alignment of a fundamental type is
1597	// always equal to its size. This is necessary in order to mimic
1598	// the i386 alignment rules on targets which might not fully align
1599	// all types (e.g. Darwin PPC32, where alignof(long long) == 4).
1600
1601	// First, some simple bookkeeping to perform for ms_struct structs.
1602	if (IsMsStruct) {
1603	// The field alignment for integer types is always the size.
1604	FieldAlign = StorageUnitSize;
1605
1606	// If the previous field was not a bitfield, or was a bitfield
1607	// with a different storage unit size, or if this field doesn't fit into
1608	// the current storage unit, we're done with that storage unit.
1609	if (LastBitfieldStorageUnitSize != StorageUnitSize ||
1610	UnfilledBitsInLastUnit < FieldSize) {
1611	// Also, ignore zero-length bitfields after non-bitfields.
1612	if (!LastBitfieldStorageUnitSize && !FieldSize)
1613	FieldAlign = 1;
1614
1615	PaddingInLastUnit = UnfilledBitsInLastUnit;
1616	UnfilledBitsInLastUnit = 0;
1617	LastBitfieldStorageUnitSize = 0;
1618	}
1619	}
1620
1621	if (isAIXLayout(Context)) {
1622	if (StorageUnitSize < Context.getTypeSize(Context.UnsignedIntTy)) {
1623	// On AIX, [bool, char, short] bitfields have the same alignment
1624	// as [unsigned].
1625	StorageUnitSize = Context.getTypeSize(Context.UnsignedIntTy);
1626	} else if (StorageUnitSize > Context.getTypeSize(Context.UnsignedIntTy) &&
1627	Context.getTargetInfo().getTriple().isArch32Bit() &&
1628	FieldSize <= 32) {
1629	// Under 32-bit compile mode, the bitcontainer is 32 bits if a single
1630	// long long bitfield has length no greater than 32 bits.
1631	StorageUnitSize = 32;
1632
1633	if (!AlignIsRequired)
1634	FieldAlign = 32;
1635	}
1636
1637	if (FieldAlign < StorageUnitSize) {
1638	// The bitfield alignment should always be greater than or equal to
1639	// bitcontainer size.
1640	FieldAlign = StorageUnitSize;
1641	}
1642	}
1643
1644	// If the field is wider than its declared type, it follows
1645	// different rules in all cases, except on AIX.
1646	// On AIX, wide bitfield follows the same rules as normal bitfield.
1647	if (FieldSize > StorageUnitSize && !isAIXLayout(Context)) {
1648	LayoutWideBitField(FieldSize, StorageUnitSize, FieldPacked, D);
1649	return;
1650	}
1651
1652	// Compute the next available bit offset.
1653	uint64_t FieldOffset =
1654	IsUnion ? 0 : (getDataSizeInBits() - UnfilledBitsInLastUnit);
1655
1656	// Handle targets that don't honor bitfield type alignment.
1657	if (!IsMsStruct && !Context.getTargetInfo().useBitFieldTypeAlignment()) {
1658	// Some such targets do honor it on zero-width bitfields.
1659	if (FieldSize == 0 &&
1660	Context.getTargetInfo().useZeroLengthBitfieldAlignment()) {
1661	// Some targets don't honor leading zero-width bitfield.
1662	if (!IsUnion && FieldOffset == 0 &&
1663	!Context.getTargetInfo().useLeadingZeroLengthBitfield())
1664	FieldAlign = 1;
1665	else {
1666	// The alignment to round up to is the max of the field's natural
1667	// alignment and a target-specific fixed value (sometimes zero).
1668	unsigned ZeroLengthBitfieldBoundary =
1669	Context.getTargetInfo().getZeroLengthBitfieldBoundary();
1670	FieldAlign = std::max(a: FieldAlign, b: ZeroLengthBitfieldBoundary);
1671	}
1672	// If that doesn't apply, just ignore the field alignment.
1673	} else {
1674	FieldAlign = 1;
1675	}
1676	}
1677
1678	// Remember the alignment we would have used if the field were not packed.
1679	unsigned UnpackedFieldAlign = FieldAlign;
1680
1681	// Ignore the field alignment if the field is packed unless it has zero-size.
1682	if (!IsMsStruct && FieldPacked && FieldSize != 0)
1683	FieldAlign = 1;
1684
1685	// But, if there's an 'aligned' attribute on the field, honor that.
1686	unsigned ExplicitFieldAlign = D->getMaxAlignment();
1687	if (ExplicitFieldAlign) {
1688	FieldAlign = std::max(a: FieldAlign, b: ExplicitFieldAlign);
1689	UnpackedFieldAlign = std::max(a: UnpackedFieldAlign, b: ExplicitFieldAlign);
1690	}
1691
1692	// But, if there's a #pragma pack in play, that takes precedent over
1693	// even the 'aligned' attribute, for non-zero-width bitfields.
1694	unsigned MaxFieldAlignmentInBits = Context.toBits(CharSize: MaxFieldAlignment);
1695	if (!MaxFieldAlignment.isZero() && FieldSize) {
1696	UnpackedFieldAlign = std::min(a: UnpackedFieldAlign, b: MaxFieldAlignmentInBits);
1697	if (FieldPacked)
1698	FieldAlign = UnpackedFieldAlign;
1699	else
1700	FieldAlign = std::min(a: FieldAlign, b: MaxFieldAlignmentInBits);
1701	}
1702
1703	// But, ms_struct just ignores all of that in unions, even explicit
1704	// alignment attributes.
1705	if (IsMsStruct && IsUnion) {
1706	FieldAlign = UnpackedFieldAlign = 1;
1707	}
1708
1709	// For purposes of diagnostics, we're going to simultaneously
1710	// compute the field offsets that we would have used if we weren't
1711	// adding any alignment padding or if the field weren't packed.
1712	uint64_t UnpaddedFieldOffset = FieldOffset - PaddingInLastUnit;
1713	uint64_t UnpackedFieldOffset = FieldOffset;
1714
1715	// Check if we need to add padding to fit the bitfield within an
1716	// allocation unit with the right size and alignment. The rules are
1717	// somewhat different here for ms_struct structs.
1718	if (IsMsStruct) {
1719	// If it's not a zero-width bitfield, and we can fit the bitfield
1720	// into the active storage unit (and we haven't already decided to
1721	// start a new storage unit), just do so, regardless of any other
1722	// other consideration. Otherwise, round up to the right alignment.
1723	if (FieldSize == 0 || FieldSize > UnfilledBitsInLastUnit) {
1724	FieldOffset = llvm::alignTo(Value: FieldOffset, Align: FieldAlign);
1725	UnpackedFieldOffset =
1726	llvm::alignTo(Value: UnpackedFieldOffset, Align: UnpackedFieldAlign);
1727	UnfilledBitsInLastUnit = 0;
1728	}
1729
1730	} else {
1731	// #pragma pack, with any value, suppresses the insertion of padding.
1732	bool AllowPadding = MaxFieldAlignment.isZero();
1733
1734	// Compute the real offset.
1735	if (FieldSize == 0 ||
1736	(AllowPadding &&
1737	(FieldOffset & (FieldAlign - 1)) + FieldSize > StorageUnitSize)) {
1738	FieldOffset = llvm::alignTo(Value: FieldOffset, Align: FieldAlign);
1739	} else if (ExplicitFieldAlign &&
1740	(MaxFieldAlignmentInBits == 0 ||
1741	ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
1742	Context.getTargetInfo().useExplicitBitFieldAlignment()) {
1743	// TODO: figure it out what needs to be done on targets that don't honor
1744	// bit-field type alignment like ARM APCS ABI.
1745	FieldOffset = llvm::alignTo(Value: FieldOffset, Align: ExplicitFieldAlign);
1746	}
1747
1748	// Repeat the computation for diagnostic purposes.
1749	if (FieldSize == 0 ||
1750	(AllowPadding &&
1751	(UnpackedFieldOffset & (UnpackedFieldAlign - 1)) + FieldSize >
1752	StorageUnitSize))
1753	UnpackedFieldOffset =
1754	llvm::alignTo(Value: UnpackedFieldOffset, Align: UnpackedFieldAlign);
1755	else if (ExplicitFieldAlign &&
1756	(MaxFieldAlignmentInBits == 0 ||
1757	ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
1758	Context.getTargetInfo().useExplicitBitFieldAlignment())
1759	UnpackedFieldOffset =
1760	llvm::alignTo(Value: UnpackedFieldOffset, Align: ExplicitFieldAlign);
1761	}
1762
1763	// If we're using external layout, give the external layout a chance
1764	// to override this information.
1765	if (UseExternalLayout)
1766	FieldOffset = updateExternalFieldOffset(Field: D, ComputedOffset: FieldOffset);
1767
1768	// Okay, place the bitfield at the calculated offset.
1769	FieldOffsets.push_back(Elt: FieldOffset);
1770
1771	// Bookkeeping:
1772
1773	// Anonymous members don't affect the overall record alignment,
1774	// except on targets where they do.
1775	if (!IsMsStruct &&
1776	!Context.getTargetInfo().useZeroLengthBitfieldAlignment() &&
1777	!D->getIdentifier())
1778	FieldAlign = UnpackedFieldAlign = 1;
1779
1780	// On AIX, zero-width bitfields pad out to the natural alignment boundary,
1781	// but do not increase the alignment greater than the MaxFieldAlignment, or 1
1782	// if packed.
1783	if (isAIXLayout(Context) && !FieldSize) {
1784	if (FieldPacked)
1785	FieldAlign = 1;
1786	if (!MaxFieldAlignment.isZero()) {
1787	UnpackedFieldAlign =
1788	std::min(a: UnpackedFieldAlign, b: MaxFieldAlignmentInBits);
1789	FieldAlign = std::min(a: FieldAlign, b: MaxFieldAlignmentInBits);
1790	}
1791	}
1792
1793	// Diagnose differences in layout due to padding or packing.
1794	if (!UseExternalLayout)
1795	CheckFieldPadding(Offset: FieldOffset, UnpaddedOffset: UnpaddedFieldOffset, UnpackedOffset: UnpackedFieldOffset,
1796	UnpackedAlign: UnpackedFieldAlign, isPacked: FieldPacked, D);
1797
1798	// Update DataSize to include the last byte containing (part of) the bitfield.
1799
1800	// For unions, this is just a max operation, as usual.
1801	if (IsUnion) {
1802	// For ms_struct, allocate the entire storage unit --- unless this
1803	// is a zero-width bitfield, in which case just use a size of 1.
1804	uint64_t RoundedFieldSize;
1805	if (IsMsStruct) {
1806	RoundedFieldSize = (FieldSize ? StorageUnitSize
1807	: Context.getTargetInfo().getCharWidth());
1808
1809	// Otherwise, allocate just the number of bytes required to store
1810	// the bitfield.
1811	} else {
1812	RoundedFieldSize = roundUpSizeToCharAlignment(Size: FieldSize, Context);
1813	}
1814	setDataSize(std::max(a: getDataSizeInBits(), b: RoundedFieldSize));
1815
1816	// For non-zero-width bitfields in ms_struct structs, allocate a new
1817	// storage unit if necessary.
1818	} else if (IsMsStruct && FieldSize) {
1819	// We should have cleared UnfilledBitsInLastUnit in every case
1820	// where we changed storage units.
1821	if (!UnfilledBitsInLastUnit) {
1822	setDataSize(FieldOffset + StorageUnitSize);
1823	UnfilledBitsInLastUnit = StorageUnitSize;
1824	}
1825	UnfilledBitsInLastUnit -= FieldSize;
1826	LastBitfieldStorageUnitSize = StorageUnitSize;
1827
1828	// Otherwise, bump the data size up to include the bitfield,
1829	// including padding up to char alignment, and then remember how
1830	// bits we didn't use.
1831	} else {
1832	uint64_t NewSizeInBits = FieldOffset + FieldSize;
1833	uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
1834	setDataSize(llvm::alignTo(Value: NewSizeInBits, Align: CharAlignment));
1835	UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;
1836
1837	// The only time we can get here for an ms_struct is if this is a
1838	// zero-width bitfield, which doesn't count as anything for the
1839	// purposes of unfilled bits.
1840	LastBitfieldStorageUnitSize = 0;
1841	}
1842
1843	// Update the size.
1844	setSize(std::max(a: getSizeInBits(), b: getDataSizeInBits()));
1845
1846	// Remember max struct/class alignment.
1847	UnadjustedAlignment =
1848	std::max(a: UnadjustedAlignment, b: Context.toCharUnitsFromBits(BitSize: FieldAlign));
1849	UpdateAlignment(NewAlignment: Context.toCharUnitsFromBits(BitSize: FieldAlign),
1850	UnpackedNewAlignment: Context.toCharUnitsFromBits(BitSize: UnpackedFieldAlign));
1851	}
1852
1853	void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D,
1854	bool InsertExtraPadding) {
1855	auto *FieldClass = D->getType()->getAsCXXRecordDecl();
1856	bool IsOverlappingEmptyField =
1857	D->isPotentiallyOverlapping() && FieldClass->isEmpty();
1858
1859	CharUnits FieldOffset =
1860	(IsUnion || IsOverlappingEmptyField) ? CharUnits::Zero() : getDataSize();
1861
1862	const bool DefaultsToAIXPowerAlignment =
1863	Context.getTargetInfo().defaultsToAIXPowerAlignment();
1864	bool FoundFirstNonOverlappingEmptyFieldForAIX = false;
1865	if (DefaultsToAIXPowerAlignment && !HandledFirstNonOverlappingEmptyField) {
1866	assert(FieldOffset == CharUnits::Zero() &&
1867	"The first non-overlapping empty field should have been handled.");
1868
1869	if (!IsOverlappingEmptyField) {
1870	FoundFirstNonOverlappingEmptyFieldForAIX = true;
1871
1872	// We're going to handle the "first member" based on
1873	// `FoundFirstNonOverlappingEmptyFieldForAIX` during the current
1874	// invocation of this function; record it as handled for future
1875	// invocations (except for unions, because the current field does not
1876	// represent all "firsts").
1877	HandledFirstNonOverlappingEmptyField = !IsUnion;
1878	}
1879	}
1880
1881	if (D->isBitField()) {
1882	LayoutBitField(D);
1883	return;
1884	}
1885
1886	uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;
1887	// Reset the unfilled bits.
1888	UnfilledBitsInLastUnit = 0;
1889	LastBitfieldStorageUnitSize = 0;
1890
1891	llvm::Triple Target = Context.getTargetInfo().getTriple();
1892
1893	AlignRequirementKind AlignRequirement = AlignRequirementKind::None;
1894	CharUnits FieldSize;
1895	CharUnits FieldAlign;
1896	// The amount of this class's dsize occupied by the field.
1897	// This is equal to FieldSize unless we're permitted to pack
1898	// into the field's tail padding.
1899	CharUnits EffectiveFieldSize;
1900
1901	auto setDeclInfo = [&](bool IsIncompleteArrayType) {
1902	auto TI = Context.getTypeInfoInChars(D->getType());
1903	FieldAlign = TI.Align;
1904	// Flexible array members don't have any size, but they have to be
1905	// aligned appropriately for their element type.
1906	EffectiveFieldSize = FieldSize =
1907	IsIncompleteArrayType ? CharUnits::Zero() : TI.Width;
1908	AlignRequirement = TI.AlignRequirement;
1909	};
1910
1911	if (D->getType()->isIncompleteArrayType()) {
1912	setDeclInfo(true /* IsIncompleteArrayType */);
1913	} else {
1914	setDeclInfo(false /* IsIncompleteArrayType */);
1915
1916	// A potentially-overlapping field occupies its dsize or nvsize, whichever
1917	// is larger.
1918	if (D->isPotentiallyOverlapping()) {
1919	const ASTRecordLayout &Layout = Context.getASTRecordLayout(D: FieldClass);
1920	EffectiveFieldSize =
1921	std::max(a: Layout.getNonVirtualSize(), b: Layout.getDataSize());
1922	}
1923
1924	if (IsMsStruct) {
1925	// If MS bitfield layout is required, figure out what type is being
1926	// laid out and align the field to the width of that type.
1927
1928	// Resolve all typedefs down to their base type and round up the field
1929	// alignment if necessary.
1930	QualType T = Context.getBaseElementType(D->getType());
1931	if (const BuiltinType *BTy = T->getAs<BuiltinType>()) {
1932	CharUnits TypeSize = Context.getTypeSizeInChars(BTy);
1933
1934	if (!llvm::isPowerOf2_64(Value: TypeSize.getQuantity())) {
1935	assert(
1936	!Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() &&
1937	"Non PowerOf2 size in MSVC mode");
1938	// Base types with sizes that aren't a power of two don't work
1939	// with the layout rules for MS structs. This isn't an issue in
1940	// MSVC itself since there are no such base data types there.
1941	// On e.g. x86_32 mingw and linux, long double is 12 bytes though.
1942	// Any structs involving that data type obviously can't be ABI
1943	// compatible with MSVC regardless of how it is laid out.
1944
1945	// Since ms_struct can be mass enabled (via a pragma or via the
1946	// -mms-bitfields command line parameter), this can trigger for
1947	// structs that don't actually need MSVC compatibility, so we
1948	// need to be able to sidestep the ms_struct layout for these types.
1949
1950	// Since the combination of -mms-bitfields together with structs
1951	// like max_align_t (which contains a long double) for mingw is
1952	// quite common (and GCC handles it silently), just handle it
1953	// silently there. For other targets that have ms_struct enabled
1954	// (most probably via a pragma or attribute), trigger a diagnostic
1955	// that defaults to an error.
1956	if (!Context.getTargetInfo().getTriple().isWindowsGNUEnvironment())
1957	Diag(D->getLocation(), diag::warn_npot_ms_struct);
1958	}
1959	if (TypeSize > FieldAlign &&
1960	llvm::isPowerOf2_64(Value: TypeSize.getQuantity()))
1961	FieldAlign = TypeSize;
1962	}
1963	}
1964	}
1965
1966	bool FieldPacked = (Packed && (!FieldClass || FieldClass->isPOD() ||
1967	FieldClass->hasAttr<PackedAttr>() ||
1968	Context.getLangOpts().getClangABICompat() <=
1969	LangOptions::ClangABI::Ver15 ||
1970	Target.isPS() || Target.isOSDarwin() ||
1971	Target.isOSAIX())) ||
1972	D->hasAttr<PackedAttr>();
1973
1974	// When used as part of a typedef, or together with a 'packed' attribute, the
1975	// 'aligned' attribute can be used to decrease alignment. In that case, it
1976	// overrides any computed alignment we have, and there is no need to upgrade
1977	// the alignment.
1978	auto alignedAttrCanDecreaseAIXAlignment = [AlignRequirement, FieldPacked] {
1979	// Enum alignment sources can be safely ignored here, because this only
1980	// helps decide whether we need the AIX alignment upgrade, which only
1981	// applies to floating-point types.
1982	return AlignRequirement == AlignRequirementKind::RequiredByTypedef ||
1983	(AlignRequirement == AlignRequirementKind::RequiredByRecord &&
1984	FieldPacked);
1985	};
1986
1987	// The AIX `power` alignment rules apply the natural alignment of the
1988	// "first member" if it is of a floating-point data type (or is an aggregate
1989	// whose recursively "first" member or element is such a type). The alignment
1990	// associated with these types for subsequent members use an alignment value
1991	// where the floating-point data type is considered to have 4-byte alignment.
1992	//
1993	// For the purposes of the foregoing: vtable pointers, non-empty base classes,
1994	// and zero-width bit-fields count as prior members; members of empty class
1995	// types marked `no_unique_address` are not considered to be prior members.
1996	CharUnits PreferredAlign = FieldAlign;
1997	if (DefaultsToAIXPowerAlignment && !alignedAttrCanDecreaseAIXAlignment() &&
1998	(FoundFirstNonOverlappingEmptyFieldForAIX || IsNaturalAlign)) {
1999	auto performBuiltinTypeAlignmentUpgrade = [&](const BuiltinType *BTy) {
2000	if (BTy->getKind() == BuiltinType::Double ||
2001	BTy->getKind() == BuiltinType::LongDouble) {
2002	assert(PreferredAlign == CharUnits::fromQuantity(4) &&
2003	"No need to upgrade the alignment value.");
2004	PreferredAlign = CharUnits::fromQuantity(Quantity: 8);
2005	}
2006	};
2007
2008	const Type *BaseTy = D->getType()->getBaseElementTypeUnsafe();
2009	if (const ComplexType *CTy = BaseTy->getAs<ComplexType>()) {
2010	performBuiltinTypeAlignmentUpgrade(
2011	CTy->getElementType()->castAs<BuiltinType>());
2012	} else if (const BuiltinType *BTy = BaseTy->getAs<BuiltinType>()) {
2013	performBuiltinTypeAlignmentUpgrade(BTy);
2014	} else if (const RecordType *RT = BaseTy->getAs<RecordType>()) {
2015	const RecordDecl *RD = RT->getDecl();
2016	assert(RD && "Expected non-null RecordDecl.");
2017	const ASTRecordLayout &FieldRecord = Context.getASTRecordLayout(D: RD);
2018	PreferredAlign = FieldRecord.getPreferredAlignment();
2019	}
2020	}
2021
2022	// The align if the field is not packed. This is to check if the attribute
2023	// was unnecessary (-Wpacked).
2024	CharUnits UnpackedFieldAlign = FieldAlign;
2025	CharUnits PackedFieldAlign = CharUnits::One();
2026	CharUnits UnpackedFieldOffset = FieldOffset;
2027	CharUnits OriginalFieldAlign = UnpackedFieldAlign;
2028
2029	CharUnits MaxAlignmentInChars =
2030	Context.toCharUnitsFromBits(BitSize: D->getMaxAlignment());
2031	PackedFieldAlign = std::max(a: PackedFieldAlign, b: MaxAlignmentInChars);
2032	PreferredAlign = std::max(a: PreferredAlign, b: MaxAlignmentInChars);
2033	UnpackedFieldAlign = std::max(a: UnpackedFieldAlign, b: MaxAlignmentInChars);
2034
2035	// The maximum field alignment overrides the aligned attribute.
2036	if (!MaxFieldAlignment.isZero()) {
2037	PackedFieldAlign = std::min(a: PackedFieldAlign, b: MaxFieldAlignment);
2038	PreferredAlign = std::min(a: PreferredAlign, b: MaxFieldAlignment);
2039	UnpackedFieldAlign = std::min(a: UnpackedFieldAlign, b: MaxFieldAlignment);
2040	}
2041
2042
2043	if (!FieldPacked)
2044	FieldAlign = UnpackedFieldAlign;
2045	if (DefaultsToAIXPowerAlignment)
2046	UnpackedFieldAlign = PreferredAlign;
2047	if (FieldPacked) {
2048	PreferredAlign = PackedFieldAlign;
2049	FieldAlign = PackedFieldAlign;
2050	}
2051
2052	CharUnits AlignTo =
2053	!DefaultsToAIXPowerAlignment ? FieldAlign : PreferredAlign;
2054	// Round up the current record size to the field's alignment boundary.
2055	FieldOffset = FieldOffset.alignTo(Align: AlignTo);
2056	UnpackedFieldOffset = UnpackedFieldOffset.alignTo(Align: UnpackedFieldAlign);
2057
2058	if (UseExternalLayout) {
2059	FieldOffset = Context.toCharUnitsFromBits(
2060	BitSize: updateExternalFieldOffset(Field: D, ComputedOffset: Context.toBits(CharSize: FieldOffset)));
2061
2062	if (!IsUnion && EmptySubobjects) {
2063	// Record the fact that we're placing a field at this offset.
2064	bool Allowed = EmptySubobjects->CanPlaceFieldAtOffset(FD: D, Offset: FieldOffset);
2065	(void)Allowed;
2066	assert(Allowed && "Externally-placed field cannot be placed here");
2067	}
2068	} else {
2069	if (!IsUnion && EmptySubobjects) {
2070	// Check if we can place the field at this offset.
2071	while (!EmptySubobjects->CanPlaceFieldAtOffset(FD: D, Offset: FieldOffset)) {
2072	// We couldn't place the field at the offset. Try again at a new offset.
2073	// We try offset 0 (for an empty field) and then dsize(C) onwards.
2074	if (FieldOffset == CharUnits::Zero() &&
2075	getDataSize() != CharUnits::Zero())
2076	FieldOffset = getDataSize().alignTo(Align: AlignTo);
2077	else
2078	FieldOffset += AlignTo;
2079	}
2080	}
2081	}
2082
2083	// Place this field at the current location.
2084	FieldOffsets.push_back(Elt: Context.toBits(CharSize: FieldOffset));
2085
2086	if (!UseExternalLayout)
2087	CheckFieldPadding(Offset: Context.toBits(CharSize: FieldOffset), UnpaddedOffset: UnpaddedFieldOffset,
2088	UnpackedOffset: Context.toBits(CharSize: UnpackedFieldOffset),
2089	UnpackedAlign: Context.toBits(CharSize: UnpackedFieldAlign), isPacked: FieldPacked, D);
2090
2091	if (InsertExtraPadding) {
2092	CharUnits ASanAlignment = CharUnits::fromQuantity(Quantity: 8);
2093	CharUnits ExtraSizeForAsan = ASanAlignment;
2094	if (FieldSize % ASanAlignment)
2095	ExtraSizeForAsan +=
2096	ASanAlignment - CharUnits::fromQuantity(Quantity: FieldSize % ASanAlignment);
2097	EffectiveFieldSize = FieldSize = FieldSize + ExtraSizeForAsan;
2098	}
2099
2100	// Reserve space for this field.
2101	if (!IsOverlappingEmptyField) {
2102	uint64_t EffectiveFieldSizeInBits = Context.toBits(CharSize: EffectiveFieldSize);
2103	if (IsUnion)
2104	setDataSize(std::max(a: getDataSizeInBits(), b: EffectiveFieldSizeInBits));
2105	else
2106	setDataSize(FieldOffset + EffectiveFieldSize);
2107
2108	PaddedFieldSize = std::max(a: PaddedFieldSize, b: FieldOffset + FieldSize);
2109	setSize(std::max(a: getSizeInBits(), b: getDataSizeInBits()));
2110	} else {
2111	setSize(std::max(a: getSizeInBits(),
2112	b: (uint64_t)Context.toBits(CharSize: FieldOffset + FieldSize)));
2113	}
2114
2115	// Remember max struct/class ABI-specified alignment.
2116	UnadjustedAlignment = std::max(a: UnadjustedAlignment, b: FieldAlign);
2117	UpdateAlignment(NewAlignment: FieldAlign, UnpackedNewAlignment: UnpackedFieldAlign, PreferredAlignment: PreferredAlign);
2118
2119	// For checking the alignment of inner fields against
2120	// the alignment of its parent record.
2121	if (const RecordDecl *RD = D->getParent()) {
2122	// Check if packed attribute or pragma pack is present.
2123	if (RD->hasAttr<PackedAttr>() || !MaxFieldAlignment.isZero())
2124	if (FieldAlign < OriginalFieldAlign)
2125	if (D->getType()->isRecordType()) {
2126	// If the offset is a multiple of the alignment of
2127	// the type, raise the warning.
2128	// TODO: Takes no account the alignment of the outer struct
2129	if (FieldOffset % OriginalFieldAlign != 0)
2130	Diag(D->getLocation(), diag::warn_unaligned_access)
2131	<< Context.getTypeDeclType(RD) << D->getName() << D->getType();
2132	}
2133	}
2134
2135	if (Packed && !FieldPacked && PackedFieldAlign < FieldAlign)
2136	Diag(D->getLocation(), diag::warn_unpacked_field) << D;
2137	}
2138
2139	void ItaniumRecordLayoutBuilder::FinishLayout(const NamedDecl *D) {
2140	// In C++, records cannot be of size 0.
2141	if (Context.getLangOpts().CPlusPlus && getSizeInBits() == 0) {
2142	if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Val: D)) {
2143	// Compatibility with gcc requires a class (pod or non-pod)
2144	// which is not empty but of size 0; such as having fields of
2145	// array of zero-length, remains of Size 0
2146	if (RD->isEmpty())
2147	setSize(CharUnits::One());
2148	}
2149	else
2150	setSize(CharUnits::One());
2151	}
2152
2153	// If we have any remaining field tail padding, include that in the overall
2154	// size.
2155	setSize(std::max(a: getSizeInBits(), b: (uint64_t)Context.toBits(CharSize: PaddedFieldSize)));
2156
2157	// Finally, round the size of the record up to the alignment of the
2158	// record itself.
2159	uint64_t UnpaddedSize = getSizeInBits() - UnfilledBitsInLastUnit;
2160	uint64_t UnpackedSizeInBits =
2161	llvm::alignTo(Value: getSizeInBits(), Align: Context.toBits(CharSize: UnpackedAlignment));
2162
2163	uint64_t RoundedSize = llvm::alignTo(
2164	Value: getSizeInBits(),
2165	Align: Context.toBits(CharSize: !Context.getTargetInfo().defaultsToAIXPowerAlignment()
2166	? Alignment
2167	: PreferredAlignment));
2168
2169	if (UseExternalLayout) {
2170	// If we're inferring alignment, and the external size is smaller than
2171	// our size after we've rounded up to alignment, conservatively set the
2172	// alignment to 1.
2173	if (InferAlignment && External.Size < RoundedSize) {
2174	Alignment = CharUnits::One();
2175	PreferredAlignment = CharUnits::One();
2176	InferAlignment = false;
2177	}
2178	setSize(External.Size);
2179	return;
2180	}
2181
2182	// Set the size to the final size.
2183	setSize(RoundedSize);
2184
2185	unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
2186	if (const RecordDecl *RD = dyn_cast<RecordDecl>(Val: D)) {
2187	// Warn if padding was introduced to the struct/class/union.
2188	if (getSizeInBits() > UnpaddedSize) {
2189	unsigned PadSize = getSizeInBits() - UnpaddedSize;
2190	bool InBits = true;
2191	if (PadSize % CharBitNum == 0) {
2192	PadSize = PadSize / CharBitNum;
2193	InBits = false;
2194	}
2195	Diag(RD->getLocation(), diag::warn_padded_struct_size)
2196	<< Context.getTypeDeclType(RD)
2197	<< PadSize
2198	<< (InBits ? 1 : 0); // (byte|bit)
2199	}
2200
2201	const auto *CXXRD = dyn_cast<CXXRecordDecl>(Val: RD);
2202
2203	// Warn if we packed it unnecessarily, when the unpacked alignment is not
2204	// greater than the one after packing, the size in bits doesn't change and
2205	// the offset of each field is identical.
2206	// Unless the type is non-POD (for Clang ABI > 15), where the packed
2207	// attribute on such a type does allow the type to be packed into other
2208	// structures that use the packed attribute.
2209	if (Packed && UnpackedAlignment <= Alignment &&
2210	UnpackedSizeInBits == getSizeInBits() && !HasPackedField &&
2211	(!CXXRD || CXXRD->isPOD() ||
2212	Context.getLangOpts().getClangABICompat() <=
2213	LangOptions::ClangABI::Ver15))
2214	Diag(D->getLocation(), diag::warn_unnecessary_packed)
2215	<< Context.getTypeDeclType(RD);
2216	}
2217	}
2218
2219	void ItaniumRecordLayoutBuilder::UpdateAlignment(
2220	CharUnits NewAlignment, CharUnits UnpackedNewAlignment,
2221	CharUnits PreferredNewAlignment) {
2222	// The alignment is not modified when using 'mac68k' alignment or when
2223	// we have an externally-supplied layout that also provides overall alignment.
2224	if (IsMac68kAlign || (UseExternalLayout && !InferAlignment))
2225	return;
2226
2227	if (NewAlignment > Alignment) {
2228	assert(llvm::isPowerOf2_64(NewAlignment.getQuantity()) &&
2229	"Alignment not a power of 2");
2230	Alignment = NewAlignment;
2231	}
2232
2233	if (UnpackedNewAlignment > UnpackedAlignment) {
2234	assert(llvm::isPowerOf2_64(UnpackedNewAlignment.getQuantity()) &&
2235	"Alignment not a power of 2");
2236	UnpackedAlignment = UnpackedNewAlignment;
2237	}
2238
2239	if (PreferredNewAlignment > PreferredAlignment) {
2240	assert(llvm::isPowerOf2_64(PreferredNewAlignment.getQuantity()) &&
2241	"Alignment not a power of 2");
2242	PreferredAlignment = PreferredNewAlignment;
2243	}
2244	}
2245
2246	uint64_t
2247	ItaniumRecordLayoutBuilder::updateExternalFieldOffset(const FieldDecl *Field,
2248	uint64_t ComputedOffset) {
2249	uint64_t ExternalFieldOffset = External.getExternalFieldOffset(FD: Field);
2250
2251	if (InferAlignment && ExternalFieldOffset < ComputedOffset) {
2252	// The externally-supplied field offset is before the field offset we
2253	// computed. Assume that the structure is packed.
2254	Alignment = CharUnits::One();
2255	PreferredAlignment = CharUnits::One();
2256	InferAlignment = false;
2257	}
2258
2259	// Use the externally-supplied field offset.
2260	return ExternalFieldOffset;
2261	}
2262
2263	/// Get diagnostic %select index for tag kind for
2264	/// field padding diagnostic message.
2265	/// WARNING: Indexes apply to particular diagnostics only!
2266	///
2267	/// \returns diagnostic %select index.
2268	static unsigned getPaddingDiagFromTagKind(TagTypeKind Tag) {
2269	switch (Tag) {
2270	case TagTypeKind::Struct:
2271	return 0;
2272	case TagTypeKind::Interface:
2273	return 1;
2274	case TagTypeKind::Class:
2275	return 2;
2276	default: llvm_unreachable("Invalid tag kind for field padding diagnostic!");
2277	}
2278	}
2279
2280	static void CheckFieldPadding(const ASTContext &Context, bool IsUnion,
2281	uint64_t Offset, uint64_t UnpaddedOffset,
2282	const FieldDecl *D) {
2283	// We let objc ivars without warning, objc interfaces generally are not used
2284	// for padding tricks.
2285	if (isa<ObjCIvarDecl>(Val: D))
2286	return;
2287
2288	// Don't warn about structs created without a SourceLocation. This can
2289	// be done by clients of the AST, such as codegen.
2290	if (D->getLocation().isInvalid())
2291	return;
2292
2293	unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
2294
2295	// Warn if padding was introduced to the struct/class.
2296	if (!IsUnion && Offset > UnpaddedOffset) {
2297	unsigned PadSize = Offset - UnpaddedOffset;
2298	bool InBits = true;
2299	if (PadSize % CharBitNum == 0) {
2300	PadSize = PadSize / CharBitNum;
2301	InBits = false;
2302	}
2303	if (D->getIdentifier()) {
2304	auto Diagnostic = D->isBitField() ? diag::warn_padded_struct_bitfield
2305	: diag::warn_padded_struct_field;
2306	Context.getDiagnostics().Report(D->getLocation(),
2307	Diagnostic)
2308	<< getPaddingDiagFromTagKind(D->getParent()->getTagKind())
2309	<< Context.getTypeDeclType(D->getParent()) << PadSize
2310	<< (InBits ? 1 : 0) // (byte|bit)
2311	<< D->getIdentifier();
2312	} else {
2313	auto Diagnostic = D->isBitField() ? diag::warn_padded_struct_anon_bitfield
2314	: diag::warn_padded_struct_anon_field;
2315	Context.getDiagnostics().Report(D->getLocation(),
2316	Diagnostic)
2317	<< getPaddingDiagFromTagKind(D->getParent()->getTagKind())
2318	<< Context.getTypeDeclType(D->getParent()) << PadSize
2319	<< (InBits ? 1 : 0); // (byte|bit)
2320	}
2321	}
2322	}
2323
2324	void ItaniumRecordLayoutBuilder::CheckFieldPadding(
2325	uint64_t Offset, uint64_t UnpaddedOffset, uint64_t UnpackedOffset,
2326	unsigned UnpackedAlign, bool isPacked, const FieldDecl *D) {
2327	::CheckFieldPadding(Context, IsUnion, Offset, UnpaddedOffset, D);
2328	if (isPacked && Offset != UnpackedOffset) {
2329	HasPackedField = true;
2330	}
2331	}
2332
2333	static const CXXMethodDecl *computeKeyFunction(ASTContext &Context,
2334	const CXXRecordDecl *RD) {
2335	// If a class isn't polymorphic it doesn't have a key function.
2336	if (!RD->isPolymorphic())
2337	return nullptr;
2338
2339	// A class that is not externally visible doesn't have a key function. (Or
2340	// at least, there's no point to assigning a key function to such a class;
2341	// this doesn't affect the ABI.)
2342	if (!RD->isExternallyVisible())
2343	return nullptr;
2344
2345	// Template instantiations don't have key functions per Itanium C++ ABI 5.2.6.
2346	// Same behavior as GCC.
2347	TemplateSpecializationKind TSK = RD->getTemplateSpecializationKind();
2348	if (TSK == TSK_ImplicitInstantiation ||
2349	TSK == TSK_ExplicitInstantiationDeclaration ||
2350	TSK == TSK_ExplicitInstantiationDefinition)
2351	return nullptr;
2352
2353	bool allowInlineFunctions =
2354	Context.getTargetInfo().getCXXABI().canKeyFunctionBeInline();
2355
2356	for (const CXXMethodDecl *MD : RD->methods()) {
2357	if (!MD->isVirtual())
2358	continue;
2359
2360	if (MD->isPureVirtual())
2361	continue;
2362
2363	// Ignore implicit member functions, they are always marked as inline, but
2364	// they don't have a body until they're defined.
2365	if (MD->isImplicit())
2366	continue;
2367
2368	if (MD->isInlineSpecified() || MD->isConstexpr())
2369	continue;
2370
2371	if (MD->hasInlineBody())
2372	continue;
2373
2374	// Ignore inline deleted or defaulted functions.
2375	if (!MD->isUserProvided())
2376	continue;
2377
2378	// In certain ABIs, ignore functions with out-of-line inline definitions.
2379	if (!allowInlineFunctions) {
2380	const FunctionDecl *Def;
2381	if (MD->hasBody(Def) && Def->isInlineSpecified())
2382	continue;
2383	}
2384
2385	if (Context.getLangOpts().CUDA) {
2386	// While compiler may see key method in this TU, during CUDA
2387	// compilation we should ignore methods that are not accessible
2388	// on this side of compilation.
2389	if (Context.getLangOpts().CUDAIsDevice) {
2390	// In device mode ignore methods without __device__ attribute.
2391	if (!MD->hasAttr<CUDADeviceAttr>())
2392	continue;
2393	} else {
2394	// In host mode ignore __device__-only methods.
2395	if (!MD->hasAttr<CUDAHostAttr>() && MD->hasAttr<CUDADeviceAttr>())
2396	continue;
2397	}
2398	}
2399
2400	// If the key function is dllimport but the class isn't, then the class has
2401	// no key function. The DLL that exports the key function won't export the
2402	// vtable in this case.
2403	if (MD->hasAttr<DLLImportAttr>() && !RD->hasAttr<DLLImportAttr>() &&
2404	!Context.getTargetInfo().hasPS4DLLImportExport())
2405	return nullptr;
2406
2407	// We found it.
2408	return MD;
2409	}
2410
2411	return nullptr;
2412	}
2413
2414	DiagnosticBuilder ItaniumRecordLayoutBuilder::Diag(SourceLocation Loc,
2415	unsigned DiagID) {
2416	return Context.getDiagnostics().Report(Loc, DiagID);
2417	}
2418
2419	/// Does the target C++ ABI require us to skip over the tail-padding
2420	/// of the given class (considering it as a base class) when allocating
2421	/// objects?
2422	static bool mustSkipTailPadding(TargetCXXABI ABI, const CXXRecordDecl *RD) {
2423	switch (ABI.getTailPaddingUseRules()) {
2424	case TargetCXXABI::AlwaysUseTailPadding:
2425	return false;
2426
2427	case TargetCXXABI::UseTailPaddingUnlessPOD03:
2428	// FIXME: To the extent that this is meant to cover the Itanium ABI
2429	// rules, we should implement the restrictions about over-sized
2430	// bitfields:
2431	//
2432	// http://itanium-cxx-abi.github.io/cxx-abi/abi.html#POD :
2433	// In general, a type is considered a POD for the purposes of
2434	// layout if it is a POD type (in the sense of ISO C++
2435	// [basic.types]). However, a POD-struct or POD-union (in the
2436	// sense of ISO C++ [class]) with a bitfield member whose
2437	// declared width is wider than the declared type of the
2438	// bitfield is not a POD for the purpose of layout. Similarly,
2439	// an array type is not a POD for the purpose of layout if the
2440	// element type of the array is not a POD for the purpose of
2441	// layout.
2442	//
2443	// Where references to the ISO C++ are made in this paragraph,
2444	// the Technical Corrigendum 1 version of the standard is
2445	// intended.
2446	return RD->isPOD();
2447
2448	case TargetCXXABI::UseTailPaddingUnlessPOD11:
2449	// This is equivalent to RD->getTypeForDecl().isCXX11PODType(),
2450	// but with a lot of abstraction penalty stripped off. This does
2451	// assume that these properties are set correctly even in C++98
2452	// mode; fortunately, that is true because we want to assign
2453	// consistently semantics to the type-traits intrinsics (or at
2454	// least as many of them as possible).
2455	return RD->isTrivial() && RD->isCXX11StandardLayout();
2456	}
2457
2458	llvm_unreachable("bad tail-padding use kind");
2459	}
2460
2461	static bool isMsLayout(const ASTContext &Context) {
2462	// Check if it's CUDA device compilation; ensure layout consistency with host.
2463	if (Context.getLangOpts().CUDA && Context.getLangOpts().CUDAIsDevice &&
2464	Context.getAuxTargetInfo())
2465	return Context.getAuxTargetInfo()->getCXXABI().isMicrosoft();
2466
2467	return Context.getTargetInfo().getCXXABI().isMicrosoft();
2468	}
2469
2470	// This section contains an implementation of struct layout that is, up to the
2471	// included tests, compatible with cl.exe (2013). The layout produced is
2472	// significantly different than those produced by the Itanium ABI. Here we note
2473	// the most important differences.
2474	//
2475	// * The alignment of bitfields in unions is ignored when computing the
2476	// alignment of the union.
2477	// * The existence of zero-width bitfield that occurs after anything other than
2478	// a non-zero length bitfield is ignored.
2479	// * There is no explicit primary base for the purposes of layout. All bases
2480	// with vfptrs are laid out first, followed by all bases without vfptrs.
2481	// * The Itanium equivalent vtable pointers are split into a vfptr (virtual
2482	// function pointer) and a vbptr (virtual base pointer). They can each be
2483	// shared with a, non-virtual bases. These bases need not be the same. vfptrs
2484	// always occur at offset 0. vbptrs can occur at an arbitrary offset and are
2485	// placed after the lexicographically last non-virtual base. This placement
2486	// is always before fields but can be in the middle of the non-virtual bases
2487	// due to the two-pass layout scheme for non-virtual-bases.
2488	// * Virtual bases sometimes require a 'vtordisp' field that is laid out before
2489	// the virtual base and is used in conjunction with virtual overrides during
2490	// construction and destruction. This is always a 4 byte value and is used as
2491	// an alternative to constructor vtables.
2492	// * vtordisps are allocated in a block of memory with size and alignment equal
2493	// to the alignment of the completed structure (before applying __declspec(
2494	// align())). The vtordisp always occur at the end of the allocation block,
2495	// immediately prior to the virtual base.
2496	// * vfptrs are injected after all bases and fields have been laid out. In
2497	// order to guarantee proper alignment of all fields, the vfptr injection
2498	// pushes all bases and fields back by the alignment imposed by those bases
2499	// and fields. This can potentially add a significant amount of padding.
2500	// vfptrs are always injected at offset 0.
2501	// * vbptrs are injected after all bases and fields have been laid out. In
2502	// order to guarantee proper alignment of all fields, the vfptr injection
2503	// pushes all bases and fields back by the alignment imposed by those bases
2504	// and fields. This can potentially add a significant amount of padding.
2505	// vbptrs are injected immediately after the last non-virtual base as
2506	// lexicographically ordered in the code. If this site isn't pointer aligned
2507	// the vbptr is placed at the next properly aligned location. Enough padding
2508	// is added to guarantee a fit.
2509	// * The last zero sized non-virtual base can be placed at the end of the
2510	// struct (potentially aliasing another object), or may alias with the first
2511	// field, even if they are of the same type.
2512	// * The last zero size virtual base may be placed at the end of the struct
2513	// potentially aliasing another object.
2514	// * The ABI attempts to avoid aliasing of zero sized bases by adding padding
2515	// between bases or vbases with specific properties. The criteria for
2516	// additional padding between two bases is that the first base is zero sized
2517	// or ends with a zero sized subobject and the second base is zero sized or
2518	// trails with a zero sized base or field (sharing of vfptrs can reorder the
2519	// layout of the so the leading base is not always the first one declared).
2520	// This rule does take into account fields that are not records, so padding
2521	// will occur even if the last field is, e.g. an int. The padding added for
2522	// bases is 1 byte. The padding added between vbases depends on the alignment
2523	// of the object but is at least 4 bytes (in both 32 and 64 bit modes).
2524	// * There is no concept of non-virtual alignment, non-virtual alignment and
2525	// alignment are always identical.
2526	// * There is a distinction between alignment and required alignment.
2527	// __declspec(align) changes the required alignment of a struct. This
2528	// alignment is _always_ obeyed, even in the presence of #pragma pack. A
2529	// record inherits required alignment from all of its fields and bases.
2530	// * __declspec(align) on bitfields has the effect of changing the bitfield's
2531	// alignment instead of its required alignment. This is the only known way
2532	// to make the alignment of a struct bigger than 8. Interestingly enough
2533	// this alignment is also immune to the effects of #pragma pack and can be
2534	// used to create structures with large alignment under #pragma pack.
2535	// However, because it does not impact required alignment, such a structure,
2536	// when used as a field or base, will not be aligned if #pragma pack is
2537	// still active at the time of use.
2538	//
2539	// Known incompatibilities:
2540	// * all: #pragma pack between fields in a record
2541	// * 2010 and back: If the last field in a record is a bitfield, every object
2542	// laid out after the record will have extra padding inserted before it. The
2543	// extra padding will have size equal to the size of the storage class of the
2544	// bitfield. 0 sized bitfields don't exhibit this behavior and the extra
2545	// padding can be avoided by adding a 0 sized bitfield after the non-zero-
2546	// sized bitfield.
2547	// * 2012 and back: In 64-bit mode, if the alignment of a record is 16 or
2548	// greater due to __declspec(align()) then a second layout phase occurs after
2549	// The locations of the vf and vb pointers are known. This layout phase
2550	// suffers from the "last field is a bitfield" bug in 2010 and results in
2551	// _every_ field getting padding put in front of it, potentially including the
2552	// vfptr, leaving the vfprt at a non-zero location which results in a fault if
2553	// anything tries to read the vftbl. The second layout phase also treats
2554	// bitfields as separate entities and gives them each storage rather than
2555	// packing them. Additionally, because this phase appears to perform a
2556	// (an unstable) sort on the members before laying them out and because merged
2557	// bitfields have the same address, the bitfields end up in whatever order
2558	// the sort left them in, a behavior we could never hope to replicate.
2559
2560	namespace {
2561	struct MicrosoftRecordLayoutBuilder {
2562	struct ElementInfo {
2563	CharUnits Size;
2564	CharUnits Alignment;
2565	};
2566	typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
2567	MicrosoftRecordLayoutBuilder(const ASTContext &Context,
2568	EmptySubobjectMap *EmptySubobjects)
2569	: Context(Context), EmptySubobjects(EmptySubobjects),
2570	RemainingBitsInField(0) {}
2571
2572	private:
2573	MicrosoftRecordLayoutBuilder(const MicrosoftRecordLayoutBuilder &) = delete;
2574	void operator=(const MicrosoftRecordLayoutBuilder &) = delete;
2575	public:
2576	void layout(const RecordDecl *RD);
2577	void cxxLayout(const CXXRecordDecl *RD);
2578	/// Initializes size and alignment and honors some flags.
2579	void initializeLayout(const RecordDecl *RD);
2580	/// Initialized C++ layout, compute alignment and virtual alignment and
2581	/// existence of vfptrs and vbptrs. Alignment is needed before the vfptr is
2582	/// laid out.
2583	void initializeCXXLayout(const CXXRecordDecl *RD);
2584	void layoutNonVirtualBases(const CXXRecordDecl *RD);
2585	void layoutNonVirtualBase(const CXXRecordDecl *RD,
2586	const CXXRecordDecl *BaseDecl,
2587	const ASTRecordLayout &BaseLayout,
2588	const ASTRecordLayout *&PreviousBaseLayout);
2589	void injectVFPtr(const CXXRecordDecl *RD);
2590	void injectVBPtr(const CXXRecordDecl *RD);
2591	/// Lays out the fields of the record. Also rounds size up to
2592	/// alignment.
2593	void layoutFields(const RecordDecl *RD);
2594	void layoutField(const FieldDecl *FD);
2595	void layoutBitField(const FieldDecl *FD);
2596	/// Lays out a single zero-width bit-field in the record and handles
2597	/// special cases associated with zero-width bit-fields.
2598	void layoutZeroWidthBitField(const FieldDecl *FD);
2599	void layoutVirtualBases(const CXXRecordDecl *RD);
2600	void finalizeLayout(const RecordDecl *RD);
2601	/// Gets the size and alignment of a base taking pragma pack and
2602	/// __declspec(align) into account.
2603	ElementInfo getAdjustedElementInfo(const ASTRecordLayout &Layout);
2604	/// Gets the size and alignment of a field taking pragma pack and
2605	/// __declspec(align) into account. It also updates RequiredAlignment as a
2606	/// side effect because it is most convenient to do so here.
2607	ElementInfo getAdjustedElementInfo(const FieldDecl *FD);
2608	/// Places a field at an offset in CharUnits.
2609	void placeFieldAtOffset(CharUnits FieldOffset) {
2610	FieldOffsets.push_back(Elt: Context.toBits(CharSize: FieldOffset));
2611	}
2612	/// Places a bitfield at a bit offset.
2613	void placeFieldAtBitOffset(uint64_t FieldOffset) {
2614	FieldOffsets.push_back(Elt: FieldOffset);
2615	}
2616	/// Compute the set of virtual bases for which vtordisps are required.
2617	void computeVtorDispSet(
2618	llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtorDispSet,
2619	const CXXRecordDecl *RD) const;
2620	const ASTContext &Context;
2621	EmptySubobjectMap *EmptySubobjects;
2622
2623	/// The size of the record being laid out.
2624	CharUnits Size;
2625	/// The non-virtual size of the record layout.
2626	CharUnits NonVirtualSize;
2627	/// The data size of the record layout.
2628	CharUnits DataSize;
2629	/// The current alignment of the record layout.
2630	CharUnits Alignment;
2631	/// The maximum allowed field alignment. This is set by #pragma pack.
2632	CharUnits MaxFieldAlignment;
2633	/// The alignment that this record must obey. This is imposed by
2634	/// __declspec(align()) on the record itself or one of its fields or bases.
2635	CharUnits RequiredAlignment;
2636	/// The size of the allocation of the currently active bitfield.
2637	/// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield
2638	/// is true.
2639	CharUnits CurrentBitfieldSize;
2640	/// Offset to the virtual base table pointer (if one exists).
2641	CharUnits VBPtrOffset;
2642	/// Minimum record size possible.
2643	CharUnits MinEmptyStructSize;
2644	/// The size and alignment info of a pointer.
2645	ElementInfo PointerInfo;
2646	/// The primary base class (if one exists).
2647	const CXXRecordDecl *PrimaryBase;
2648	/// The class we share our vb-pointer with.
2649	const CXXRecordDecl *SharedVBPtrBase;
2650	/// The collection of field offsets.
2651	SmallVector<uint64_t, 16> FieldOffsets;
2652	/// Base classes and their offsets in the record.
2653	BaseOffsetsMapTy Bases;
2654	/// virtual base classes and their offsets in the record.
2655	ASTRecordLayout::VBaseOffsetsMapTy VBases;
2656	/// The number of remaining bits in our last bitfield allocation.
2657	unsigned RemainingBitsInField;
2658	bool IsUnion : 1;
2659	/// True if the last field laid out was a bitfield and was not 0
2660	/// width.
2661	bool LastFieldIsNonZeroWidthBitfield : 1;
2662	/// True if the class has its own vftable pointer.
2663	bool HasOwnVFPtr : 1;
2664	/// True if the class has a vbtable pointer.
2665	bool HasVBPtr : 1;
2666	/// True if the last sub-object within the type is zero sized or the
2667	/// object itself is zero sized. This *does not* count members that are not
2668	/// records. Only used for MS-ABI.
2669	bool EndsWithZeroSizedObject : 1;
2670	/// True if this class is zero sized or first base is zero sized or
2671	/// has this property. Only used for MS-ABI.
2672	bool LeadsWithZeroSizedBase : 1;
2673
2674	/// True if the external AST source provided a layout for this record.
2675	bool UseExternalLayout : 1;
2676
2677	/// The layout provided by the external AST source. Only active if
2678	/// UseExternalLayout is true.
2679	ExternalLayout External;
2680	};
2681	} // namespace
2682
2683	MicrosoftRecordLayoutBuilder::ElementInfo
2684	MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
2685	const ASTRecordLayout &Layout) {
2686	ElementInfo Info;
2687	Info.Alignment = Layout.getAlignment();
2688	// Respect pragma pack.
2689	if (!MaxFieldAlignment.isZero())
2690	Info.Alignment = std::min(a: Info.Alignment, b: MaxFieldAlignment);
2691	// Track zero-sized subobjects here where it's already available.
2692	EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
2693	// Respect required alignment, this is necessary because we may have adjusted
2694	// the alignment in the case of pragma pack. Note that the required alignment
2695	// doesn't actually apply to the struct alignment at this point.
2696	Alignment = std::max(a: Alignment, b: Info.Alignment);
2697	RequiredAlignment = std::max(a: RequiredAlignment, b: Layout.getRequiredAlignment());
2698	Info.Alignment = std::max(a: Info.Alignment, b: Layout.getRequiredAlignment());
2699	Info.Size = Layout.getNonVirtualSize();
2700	return Info;
2701	}
2702
2703	MicrosoftRecordLayoutBuilder::ElementInfo
2704	MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
2705	const FieldDecl *FD) {
2706	// Get the alignment of the field type's natural alignment, ignore any
2707	// alignment attributes.
2708	auto TInfo =
2709	Context.getTypeInfoInChars(FD->getType()->getUnqualifiedDesugaredType());
2710	ElementInfo Info{TInfo.Width, TInfo.Align};
2711	// Respect align attributes on the field.
2712	CharUnits FieldRequiredAlignment =
2713	Context.toCharUnitsFromBits(BitSize: FD->getMaxAlignment());
2714	// Respect align attributes on the type.
2715	if (Context.isAlignmentRequired(FD->getType()))
2716	FieldRequiredAlignment = std::max(
2717	Context.getTypeAlignInChars(FD->getType()), FieldRequiredAlignment);
2718	// Respect attributes applied to subobjects of the field.
2719	if (FD->isBitField())
2720	// For some reason __declspec align impacts alignment rather than required
2721	// alignment when it is applied to bitfields.
2722	Info.Alignment = std::max(a: Info.Alignment, b: FieldRequiredAlignment);
2723	else {
2724	if (auto RT =
2725	FD->getType()->getBaseElementTypeUnsafe()->getAs<RecordType>()) {
2726	auto const &Layout = Context.getASTRecordLayout(D: RT->getDecl());
2727	EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
2728	FieldRequiredAlignment = std::max(FieldRequiredAlignment,
2729	Layout.getRequiredAlignment());
2730	}
2731	// Capture required alignment as a side-effect.
2732	RequiredAlignment = std::max(a: RequiredAlignment, b: FieldRequiredAlignment);
2733	}
2734	// Respect pragma pack, attribute pack and declspec align
2735	if (!MaxFieldAlignment.isZero())
2736	Info.Alignment = std::min(a: Info.Alignment, b: MaxFieldAlignment);
2737	if (FD->hasAttr<PackedAttr>())
2738	Info.Alignment = CharUnits::One();
2739	Info.Alignment = std::max(a: Info.Alignment, b: FieldRequiredAlignment);
2740	return Info;
2741	}
2742
2743	void MicrosoftRecordLayoutBuilder::layout(const RecordDecl *RD) {
2744	// For C record layout, zero-sized records always have size 4.
2745	MinEmptyStructSize = CharUnits::fromQuantity(Quantity: 4);
2746	initializeLayout(RD);
2747	layoutFields(RD);
2748	DataSize = Size = Size.alignTo(Align: Alignment);
2749	RequiredAlignment = std::max(
2750	RequiredAlignment, Context.toCharUnitsFromBits(BitSize: RD->getMaxAlignment()));
2751	finalizeLayout(RD);
2752	}
2753
2754	void MicrosoftRecordLayoutBuilder::cxxLayout(const CXXRecordDecl *RD) {
2755	// The C++ standard says that empty structs have size 1.
2756	MinEmptyStructSize = CharUnits::One();
2757	initializeLayout(RD);
2758	initializeCXXLayout(RD);
2759	layoutNonVirtualBases(RD);
2760	layoutFields(RD);
2761	injectVBPtr(RD);
2762	injectVFPtr(RD);
2763	if (HasOwnVFPtr || (HasVBPtr && !SharedVBPtrBase))
2764	Alignment = std::max(a: Alignment, b: PointerInfo.Alignment);
2765	auto RoundingAlignment = Alignment;
2766	if (!MaxFieldAlignment.isZero())
2767	RoundingAlignment = std::min(a: RoundingAlignment, b: MaxFieldAlignment);
2768	if (!UseExternalLayout)
2769	Size = Size.alignTo(Align: RoundingAlignment);
2770	NonVirtualSize = Size;
2771	RequiredAlignment = std::max(
2772	RequiredAlignment, Context.toCharUnitsFromBits(BitSize: RD->getMaxAlignment()));
2773	layoutVirtualBases(RD);
2774	finalizeLayout(RD);
2775	}
2776
2777	void MicrosoftRecordLayoutBuilder::initializeLayout(const RecordDecl *RD) {
2778	IsUnion = RD->isUnion();
2779	Size = CharUnits::Zero();
2780	Alignment = CharUnits::One();
2781	// In 64-bit mode we always perform an alignment step after laying out vbases.
2782	// In 32-bit mode we do not. The check to see if we need to perform alignment
2783	// checks the RequiredAlignment field and performs alignment if it isn't 0.
2784	RequiredAlignment = Context.getTargetInfo().getTriple().isArch64Bit()
2785	? CharUnits::One()
2786	: CharUnits::Zero();
2787	// Compute the maximum field alignment.
2788	MaxFieldAlignment = CharUnits::Zero();
2789	// Honor the default struct packing maximum alignment flag.
2790	if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct)
2791	MaxFieldAlignment = CharUnits::fromQuantity(Quantity: DefaultMaxFieldAlignment);
2792	// Honor the packing attribute. The MS-ABI ignores pragma pack if its larger
2793	// than the pointer size.
2794	if (const MaxFieldAlignmentAttr *MFAA = RD->getAttr<MaxFieldAlignmentAttr>()){
2795	unsigned PackedAlignment = MFAA->getAlignment();
2796	if (PackedAlignment <=
2797	Context.getTargetInfo().getPointerWidth(AddrSpace: LangAS::Default))
2798	MaxFieldAlignment = Context.toCharUnitsFromBits(BitSize: PackedAlignment);
2799	}
2800	// Packed attribute forces max field alignment to be 1.
2801	if (RD->hasAttr<PackedAttr>())
2802	MaxFieldAlignment = CharUnits::One();
2803
2804	// Try to respect the external layout if present.
2805	UseExternalLayout = false;
2806	if (ExternalASTSource *Source = Context.getExternalSource())
2807	UseExternalLayout = Source->layoutRecordType(
2808	Record: RD, Size&: External.Size, Alignment&: External.Align, FieldOffsets&: External.FieldOffsets,
2809	BaseOffsets&: External.BaseOffsets, VirtualBaseOffsets&: External.VirtualBaseOffsets);
2810	}
2811
2812	void
2813	MicrosoftRecordLayoutBuilder::initializeCXXLayout(const CXXRecordDecl *RD) {
2814	EndsWithZeroSizedObject = false;
2815	LeadsWithZeroSizedBase = false;
2816	HasOwnVFPtr = false;
2817	HasVBPtr = false;
2818	PrimaryBase = nullptr;
2819	SharedVBPtrBase = nullptr;
2820	// Calculate pointer size and alignment. These are used for vfptr and vbprt
2821	// injection.
2822	PointerInfo.Size = Context.toCharUnitsFromBits(
2823	BitSize: Context.getTargetInfo().getPointerWidth(AddrSpace: LangAS::Default));
2824	PointerInfo.Alignment = Context.toCharUnitsFromBits(
2825	BitSize: Context.getTargetInfo().getPointerAlign(AddrSpace: LangAS::Default));
2826	// Respect pragma pack.
2827	if (!MaxFieldAlignment.isZero())
2828	PointerInfo.Alignment = std::min(a: PointerInfo.Alignment, b: MaxFieldAlignment);
2829	}
2830
2831	void
2832	MicrosoftRecordLayoutBuilder::layoutNonVirtualBases(const CXXRecordDecl *RD) {
2833	// The MS-ABI lays out all bases that contain leading vfptrs before it lays
2834	// out any bases that do not contain vfptrs. We implement this as two passes
2835	// over the bases. This approach guarantees that the primary base is laid out
2836	// first. We use these passes to calculate some additional aggregated
2837	// information about the bases, such as required alignment and the presence of
2838	// zero sized members.
2839	const ASTRecordLayout *PreviousBaseLayout = nullptr;
2840	bool HasPolymorphicBaseClass = false;
2841	// Iterate through the bases and lay out the non-virtual ones.
2842	for (const CXXBaseSpecifier &Base : RD->bases()) {
2843	const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2844	HasPolymorphicBaseClass |= BaseDecl->isPolymorphic();
2845	const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2846	// Mark and skip virtual bases.
2847	if (Base.isVirtual()) {
2848	HasVBPtr = true;
2849	continue;
2850	}
2851	// Check for a base to share a VBPtr with.
2852	if (!SharedVBPtrBase && BaseLayout.hasVBPtr()) {
2853	SharedVBPtrBase = BaseDecl;
2854	HasVBPtr = true;
2855	}
2856	// Only lay out bases with extendable VFPtrs on the first pass.
2857	if (!BaseLayout.hasExtendableVFPtr())
2858	continue;
2859	// If we don't have a primary base, this one qualifies.
2860	if (!PrimaryBase) {
2861	PrimaryBase = BaseDecl;
2862	LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
2863	}
2864	// Lay out the base.
2865	layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
2866	}
2867	// Figure out if we need a fresh VFPtr for this class.
2868	if (RD->isPolymorphic()) {
2869	if (!HasPolymorphicBaseClass)
2870	// This class introduces polymorphism, so we need a vftable to store the
2871	// RTTI information.
2872	HasOwnVFPtr = true;
2873	else if (!PrimaryBase) {
2874	// We have a polymorphic base class but can't extend its vftable. Add a
2875	// new vfptr if we would use any vftable slots.
2876	for (CXXMethodDecl *M : RD->methods()) {
2877	if (MicrosoftVTableContext::hasVtableSlot(MD: M) &&
2878	M->size_overridden_methods() == 0) {
2879	HasOwnVFPtr = true;
2880	break;
2881	}
2882	}
2883	}
2884	}
2885	// If we don't have a primary base then we have a leading object that could
2886	// itself lead with a zero-sized object, something we track.
2887	bool CheckLeadingLayout = !PrimaryBase;
2888	// Iterate through the bases and lay out the non-virtual ones.
2889	for (const CXXBaseSpecifier &Base : RD->bases()) {
2890	if (Base.isVirtual())
2891	continue;
2892	const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2893	const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2894	// Only lay out bases without extendable VFPtrs on the second pass.
2895	if (BaseLayout.hasExtendableVFPtr()) {
2896	VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
2897	continue;
2898	}
2899	// If this is the first layout, check to see if it leads with a zero sized
2900	// object. If it does, so do we.
2901	if (CheckLeadingLayout) {
2902	CheckLeadingLayout = false;
2903	LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
2904	}
2905	// Lay out the base.
2906	layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
2907	VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
2908	}
2909	// Set our VBPtroffset if we know it at this point.
2910	if (!HasVBPtr)
2911	VBPtrOffset = CharUnits::fromQuantity(Quantity: -1);
2912	else if (SharedVBPtrBase) {
2913	const ASTRecordLayout &Layout = Context.getASTRecordLayout(SharedVBPtrBase);
2914	VBPtrOffset = Bases[SharedVBPtrBase] + Layout.getVBPtrOffset();
2915	}
2916	}
2917
2918	static bool recordUsesEBO(const RecordDecl *RD) {
2919	if (!isa<CXXRecordDecl>(Val: RD))
2920	return false;
2921	if (RD->hasAttr<EmptyBasesAttr>())
2922	return true;
2923	if (auto *LVA = RD->getAttr<LayoutVersionAttr>())
2924	// TODO: Double check with the next version of MSVC.
2925	if (LVA->getVersion() <= LangOptions::MSVC2015)
2926	return false;
2927	// TODO: Some later version of MSVC will change the default behavior of the
2928	// compiler to enable EBO by default. When this happens, we will need an
2929	// additional isCompatibleWithMSVC check.
2930	return false;
2931	}
2932
2933	void MicrosoftRecordLayoutBuilder::layoutNonVirtualBase(
2934	const CXXRecordDecl *RD, const CXXRecordDecl *BaseDecl,
2935	const ASTRecordLayout &BaseLayout,
2936	const ASTRecordLayout *&PreviousBaseLayout) {
2937	// Insert padding between two bases if the left first one is zero sized or
2938	// contains a zero sized subobject and the right is zero sized or one leads
2939	// with a zero sized base.
2940	bool MDCUsesEBO = recordUsesEBO(RD);
2941	if (PreviousBaseLayout && PreviousBaseLayout->endsWithZeroSizedObject() &&
2942	BaseLayout.leadsWithZeroSizedBase() && !MDCUsesEBO)
2943	Size++;
2944	ElementInfo Info = getAdjustedElementInfo(Layout: BaseLayout);
2945	CharUnits BaseOffset;
2946
2947	// Respect the external AST source base offset, if present.
2948	bool FoundBase = false;
2949	if (UseExternalLayout) {
2950	FoundBase = External.getExternalNVBaseOffset(RD: BaseDecl, BaseOffset);
2951	if (BaseOffset > Size) {
2952	Size = BaseOffset;
2953	}
2954	}
2955
2956	if (!FoundBase) {
2957	if (MDCUsesEBO && BaseDecl->isEmpty() &&
2958	(BaseLayout.getNonVirtualSize() == CharUnits::Zero())) {
2959	BaseOffset = CharUnits::Zero();
2960	} else {
2961	// Otherwise, lay the base out at the end of the MDC.
2962	BaseOffset = Size = Size.alignTo(Align: Info.Alignment);
2963	}
2964	}
2965	Bases.insert(KV: std::make_pair(x&: BaseDecl, y&: BaseOffset));
2966	Size += BaseLayout.getNonVirtualSize();
2967	DataSize = Size;
2968	PreviousBaseLayout = &BaseLayout;
2969	}
2970
2971	void MicrosoftRecordLayoutBuilder::layoutFields(const RecordDecl *RD) {
2972	LastFieldIsNonZeroWidthBitfield = false;
2973	for (const FieldDecl *Field : RD->fields())
2974	layoutField(FD: Field);
2975	}
2976
2977	void MicrosoftRecordLayoutBuilder::layoutField(const FieldDecl *FD) {
2978	if (FD->isBitField()) {
2979	layoutBitField(FD);
2980	return;
2981	}
2982	LastFieldIsNonZeroWidthBitfield = false;
2983	ElementInfo Info = getAdjustedElementInfo(FD);
2984	Alignment = std::max(a: Alignment, b: Info.Alignment);
2985
2986	const CXXRecordDecl *FieldClass = FD->getType()->getAsCXXRecordDecl();
2987	bool IsOverlappingEmptyField = FD->isPotentiallyOverlapping() &&
2988	FieldClass->isEmpty() &&
2989	FieldClass->fields().empty();
2990	CharUnits FieldOffset = CharUnits::Zero();
2991
2992	if (UseExternalLayout) {
2993	FieldOffset =
2994	Context.toCharUnitsFromBits(BitSize: External.getExternalFieldOffset(FD));
2995	} else if (IsUnion) {
2996	FieldOffset = CharUnits::Zero();
2997	} else if (EmptySubobjects) {
2998	if (!IsOverlappingEmptyField)
2999	FieldOffset = DataSize.alignTo(Align: Info.Alignment);
3000
3001	while (!EmptySubobjects->CanPlaceFieldAtOffset(FD, Offset: FieldOffset)) {
3002	const CXXRecordDecl *ParentClass = cast<CXXRecordDecl>(Val: FD->getParent());
3003	bool HasBases = ParentClass && (!ParentClass->bases().empty() ||
3004	!ParentClass->vbases().empty());
3005	if (FieldOffset == CharUnits::Zero() && DataSize != CharUnits::Zero() &&
3006	HasBases) {
3007	// MSVC appears to only do this when there are base classes;
3008	// otherwise it overlaps no_unique_address fields in non-zero offsets.
3009	FieldOffset = DataSize.alignTo(Align: Info.Alignment);
3010	} else {
3011	FieldOffset += Info.Alignment;
3012	}
3013	}
3014	} else {
3015	FieldOffset = Size.alignTo(Align: Info.Alignment);
3016	}
3017
3018	uint64_t UnpaddedFielddOffsetInBits =
3019	Context.toBits(CharSize: DataSize) - RemainingBitsInField;
3020
3021	::CheckFieldPadding(Context, IsUnion, Offset: Context.toBits(CharSize: FieldOffset),
3022	UnpaddedOffset: UnpaddedFielddOffsetInBits, D: FD);
3023
3024	RemainingBitsInField = 0;
3025
3026	placeFieldAtOffset(FieldOffset);
3027
3028	if (!IsOverlappingEmptyField)
3029	DataSize = std::max(a: DataSize, b: FieldOffset + Info.Size);
3030
3031	Size = std::max(a: Size, b: FieldOffset + Info.Size);
3032	}
3033
3034	void MicrosoftRecordLayoutBuilder::layoutBitField(const FieldDecl *FD) {
3035	unsigned Width = FD->getBitWidthValue();
3036	if (Width == 0) {
3037	layoutZeroWidthBitField(FD);
3038	return;
3039	}
3040	ElementInfo Info = getAdjustedElementInfo(FD);
3041	// Clamp the bitfield to a containable size for the sake of being able
3042	// to lay them out. Sema will throw an error.
3043	if (Width > Context.toBits(CharSize: Info.Size))
3044	Width = Context.toBits(CharSize: Info.Size);
3045	// Check to see if this bitfield fits into an existing allocation. Note:
3046	// MSVC refuses to pack bitfields of formal types with different sizes
3047	// into the same allocation.
3048	if (!UseExternalLayout && !IsUnion && LastFieldIsNonZeroWidthBitfield &&
3049	CurrentBitfieldSize == Info.Size && Width <= RemainingBitsInField) {
3050	placeFieldAtBitOffset(FieldOffset: Context.toBits(CharSize: Size) - RemainingBitsInField);
3051	RemainingBitsInField -= Width;
3052	return;
3053	}
3054	LastFieldIsNonZeroWidthBitfield = true;
3055	CurrentBitfieldSize = Info.Size;
3056	if (UseExternalLayout) {
3057	auto FieldBitOffset = External.getExternalFieldOffset(FD);
3058	placeFieldAtBitOffset(FieldOffset: FieldBitOffset);
3059	auto NewSize = Context.toCharUnitsFromBits(
3060	BitSize: llvm::alignDown(Value: FieldBitOffset, Align: Context.toBits(CharSize: Info.Alignment)) +
3061	Context.toBits(CharSize: Info.Size));
3062	Size = std::max(a: Size, b: NewSize);
3063	Alignment = std::max(a: Alignment, b: Info.Alignment);
3064	} else if (IsUnion) {
3065	placeFieldAtOffset(FieldOffset: CharUnits::Zero());
3066	Size = std::max(a: Size, b: Info.Size);
3067	// TODO: Add a Sema warning that MS ignores bitfield alignment in unions.
3068	} else {
3069	// Allocate a new block of memory and place the bitfield in it.
3070	CharUnits FieldOffset = Size.alignTo(Align: Info.Alignment);
3071	uint64_t UnpaddedFieldOffsetInBits =
3072	Context.toBits(CharSize: DataSize) - RemainingBitsInField;
3073	placeFieldAtOffset(FieldOffset);
3074	Size = FieldOffset + Info.Size;
3075	Alignment = std::max(a: Alignment, b: Info.Alignment);
3076	RemainingBitsInField = Context.toBits(CharSize: Info.Size) - Width;
3077	::CheckFieldPadding(Context, IsUnion, Offset: Context.toBits(CharSize: FieldOffset),
3078	UnpaddedOffset: UnpaddedFieldOffsetInBits, D: FD);
3079	}
3080	DataSize = Size;
3081	}
3082
3083	void
3084	MicrosoftRecordLayoutBuilder::layoutZeroWidthBitField(const FieldDecl *FD) {
3085	// Zero-width bitfields are ignored unless they follow a non-zero-width
3086	// bitfield.
3087	if (!LastFieldIsNonZeroWidthBitfield) {
3088	placeFieldAtOffset(FieldOffset: IsUnion ? CharUnits::Zero() : Size);
3089	// TODO: Add a Sema warning that MS ignores alignment for zero
3090	// sized bitfields that occur after zero-size bitfields or non-bitfields.
3091	return;
3092	}
3093	LastFieldIsNonZeroWidthBitfield = false;
3094	ElementInfo Info = getAdjustedElementInfo(FD);
3095	if (IsUnion) {
3096	placeFieldAtOffset(FieldOffset: CharUnits::Zero());
3097	Size = std::max(a: Size, b: Info.Size);
3098	// TODO: Add a Sema warning that MS ignores bitfield alignment in unions.
3099	} else {
3100	// Round up the current record size to the field's alignment boundary.
3101	CharUnits FieldOffset = Size.alignTo(Align: Info.Alignment);
3102	uint64_t UnpaddedFieldOffsetInBits =
3103	Context.toBits(CharSize: DataSize) - RemainingBitsInField;
3104	placeFieldAtOffset(FieldOffset);
3105	RemainingBitsInField = 0;
3106	Size = FieldOffset;
3107	Alignment = std::max(a: Alignment, b: Info.Alignment);
3108	::CheckFieldPadding(Context, IsUnion, Offset: Context.toBits(CharSize: FieldOffset),
3109	UnpaddedOffset: UnpaddedFieldOffsetInBits, D: FD);
3110	}
3111	DataSize = Size;
3112	}
3113
3114	void MicrosoftRecordLayoutBuilder::injectVBPtr(const CXXRecordDecl *RD) {
3115	if (!HasVBPtr || SharedVBPtrBase)
3116	return;
3117	// Inject the VBPointer at the injection site.
3118	CharUnits InjectionSite = VBPtrOffset;
3119	// But before we do, make sure it's properly aligned.
3120	VBPtrOffset = VBPtrOffset.alignTo(Align: PointerInfo.Alignment);
3121	// Determine where the first field should be laid out after the vbptr.
3122	CharUnits FieldStart = VBPtrOffset + PointerInfo.Size;
3123	// Shift everything after the vbptr down, unless we're using an external
3124	// layout.
3125	if (UseExternalLayout) {
3126	// It is possible that there were no fields or bases located after vbptr,
3127	// so the size was not adjusted before.
3128	if (Size < FieldStart)
3129	Size = FieldStart;
3130	return;
3131	}
3132	// Make sure that the amount we push the fields back by is a multiple of the
3133	// alignment.
3134	CharUnits Offset = (FieldStart - InjectionSite)
3135	.alignTo(Align: std::max(a: RequiredAlignment, b: Alignment));
3136	Size += Offset;
3137	for (uint64_t &FieldOffset : FieldOffsets)
3138	FieldOffset += Context.toBits(CharSize: Offset);
3139	for (BaseOffsetsMapTy::value_type &Base : Bases)
3140	if (Base.second >= InjectionSite)
3141	Base.second += Offset;
3142	}
3143
3144	void MicrosoftRecordLayoutBuilder::injectVFPtr(const CXXRecordDecl *RD) {
3145	if (!HasOwnVFPtr)
3146	return;
3147	// Make sure that the amount we push the struct back by is a multiple of the
3148	// alignment.
3149	CharUnits Offset =
3150	PointerInfo.Size.alignTo(Align: std::max(a: RequiredAlignment, b: Alignment));
3151	// Push back the vbptr, but increase the size of the object and push back
3152	// regular fields by the offset only if not using external record layout.
3153	if (HasVBPtr)
3154	VBPtrOffset += Offset;
3155
3156	if (UseExternalLayout) {
3157	// The class may have size 0 and a vfptr (e.g. it's an interface class). The
3158	// size was not correctly set before in this case.
3159	if (Size.isZero())
3160	Size += Offset;
3161	return;
3162	}
3163
3164	Size += Offset;
3165
3166	// If we're using an external layout, the fields offsets have already
3167	// accounted for this adjustment.
3168	for (uint64_t &FieldOffset : FieldOffsets)
3169	FieldOffset += Context.toBits(CharSize: Offset);
3170	for (BaseOffsetsMapTy::value_type &Base : Bases)
3171	Base.second += Offset;
3172	}
3173
3174	void MicrosoftRecordLayoutBuilder::layoutVirtualBases(const CXXRecordDecl *RD) {
3175	if (!HasVBPtr)
3176	return;
3177	// Vtordisps are always 4 bytes (even in 64-bit mode)
3178	CharUnits VtorDispSize = CharUnits::fromQuantity(Quantity: 4);
3179	CharUnits VtorDispAlignment = VtorDispSize;
3180	// vtordisps respect pragma pack.
3181	if (!MaxFieldAlignment.isZero())
3182	VtorDispAlignment = std::min(a: VtorDispAlignment, b: MaxFieldAlignment);
3183	// The alignment of the vtordisp is at least the required alignment of the
3184	// entire record. This requirement may be present to support vtordisp
3185	// injection.
3186	for (const CXXBaseSpecifier &VBase : RD->vbases()) {
3187	const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
3188	const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
3189	RequiredAlignment =
3190	std::max(a: RequiredAlignment, b: BaseLayout.getRequiredAlignment());
3191	}
3192	VtorDispAlignment = std::max(a: VtorDispAlignment, b: RequiredAlignment);
3193	// Compute the vtordisp set.
3194	llvm::SmallPtrSet<const CXXRecordDecl *, 2> HasVtorDispSet;
3195	computeVtorDispSet(HasVtorDispSet, RD);
3196	// Iterate through the virtual bases and lay them out.
3197	const ASTRecordLayout *PreviousBaseLayout = nullptr;
3198	for (const CXXBaseSpecifier &VBase : RD->vbases()) {
3199	const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
3200	const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
3201	bool HasVtordisp = HasVtorDispSet.contains(Ptr: BaseDecl);
3202	// Insert padding between two bases if the left first one is zero sized or
3203	// contains a zero sized subobject and the right is zero sized or one leads
3204	// with a zero sized base. The padding between virtual bases is 4
3205	// bytes (in both 32 and 64 bits modes) and always involves rounding up to
3206	// the required alignment, we don't know why.
3207	if ((PreviousBaseLayout && PreviousBaseLayout->endsWithZeroSizedObject() &&
3208	BaseLayout.leadsWithZeroSizedBase() && !recordUsesEBO(RD)) ||
3209	HasVtordisp) {
3210	Size = Size.alignTo(Align: VtorDispAlignment) + VtorDispSize;
3211	Alignment = std::max(a: VtorDispAlignment, b: Alignment);
3212	}
3213	// Insert the virtual base.
3214	ElementInfo Info = getAdjustedElementInfo(Layout: BaseLayout);
3215	CharUnits BaseOffset;
3216
3217	// Respect the external AST source base offset, if present.
3218	if (UseExternalLayout) {
3219	if (!External.getExternalVBaseOffset(RD: BaseDecl, BaseOffset))
3220	BaseOffset = Size;
3221	} else
3222	BaseOffset = Size.alignTo(Align: Info.Alignment);
3223
3224	assert(BaseOffset >= Size && "base offset already allocated");
3225
3226	VBases.insert(KV: std::make_pair(x&: BaseDecl,
3227	y: ASTRecordLayout::VBaseInfo(BaseOffset, HasVtordisp)));
3228	Size = BaseOffset + BaseLayout.getNonVirtualSize();
3229	PreviousBaseLayout = &BaseLayout;
3230	}
3231	}
3232
3233	void MicrosoftRecordLayoutBuilder::finalizeLayout(const RecordDecl *RD) {
3234	uint64_t UnpaddedSizeInBits = Context.toBits(CharSize: DataSize);
3235	UnpaddedSizeInBits -= RemainingBitsInField;
3236
3237	// MS ABI allocates 1 byte for empty class
3238	// (not padding)
3239	if (Size.isZero())
3240	UnpaddedSizeInBits += 8;
3241
3242	// Respect required alignment. Note that in 32-bit mode Required alignment
3243	// may be 0 and cause size not to be updated.
3244	DataSize = Size;
3245	if (!RequiredAlignment.isZero()) {
3246	Alignment = std::max(a: Alignment, b: RequiredAlignment);
3247	auto RoundingAlignment = Alignment;
3248	if (!MaxFieldAlignment.isZero())
3249	RoundingAlignment = std::min(a: RoundingAlignment, b: MaxFieldAlignment);
3250	RoundingAlignment = std::max(a: RoundingAlignment, b: RequiredAlignment);
3251	Size = Size.alignTo(Align: RoundingAlignment);
3252	}
3253	if (Size.isZero()) {
3254	if (!recordUsesEBO(RD) || !cast<CXXRecordDecl>(Val: RD)->isEmpty()) {
3255	EndsWithZeroSizedObject = true;
3256	LeadsWithZeroSizedBase = true;
3257	}
3258	// Zero-sized structures have size equal to their alignment if a
3259	// __declspec(align) came into play.
3260	if (RequiredAlignment >= MinEmptyStructSize)
3261	Size = Alignment;
3262	else
3263	Size = MinEmptyStructSize;
3264	}
3265
3266	if (UseExternalLayout) {
3267	Size = Context.toCharUnitsFromBits(BitSize: External.Size);
3268	if (External.Align)
3269	Alignment = Context.toCharUnitsFromBits(BitSize: External.Align);
3270	return;
3271	}
3272	unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
3273	uint64_t SizeInBits = Context.toBits(CharSize: Size);
3274
3275	if (SizeInBits > UnpaddedSizeInBits) {
3276	unsigned int PadSize = SizeInBits - UnpaddedSizeInBits;
3277	bool InBits = true;
3278	if (PadSize % CharBitNum == 0) {
3279	PadSize = PadSize / CharBitNum;
3280	InBits = false;
3281	}
3282
3283	Context.getDiagnostics().Report(RD->getLocation(),
3284	diag::warn_padded_struct_size)
3285	<< Context.getTypeDeclType(RD) << PadSize
3286	<< (InBits ? 1 : 0); // (byte|bit)
3287	}
3288	}
3289
3290	// Recursively walks the non-virtual bases of a class and determines if any of
3291	// them are in the bases with overridden methods set.
3292	static bool
3293	RequiresVtordisp(const llvm::SmallPtrSetImpl<const CXXRecordDecl *> &
3294	BasesWithOverriddenMethods,
3295	const CXXRecordDecl *RD) {
3296	if (BasesWithOverriddenMethods.count(Ptr: RD))
3297	return true;
3298	// If any of a virtual bases non-virtual bases (recursively) requires a
3299	// vtordisp than so does this virtual base.
3300	for (const CXXBaseSpecifier &Base : RD->bases())
3301	if (!Base.isVirtual() &&
3302	RequiresVtordisp(BasesWithOverriddenMethods,
3303	RD: Base.getType()->getAsCXXRecordDecl()))
3304	return true;
3305	return false;
3306	}
3307
3308	void MicrosoftRecordLayoutBuilder::computeVtorDispSet(
3309	llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtordispSet,
3310	const CXXRecordDecl *RD) const {
3311	// /vd2 or #pragma vtordisp(2): Always use vtordisps for virtual bases with
3312	// vftables.
3313	if (RD->getMSVtorDispMode() == MSVtorDispMode::ForVFTable) {
3314	for (const CXXBaseSpecifier &Base : RD->vbases()) {
3315	const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
3316	const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
3317	if (Layout.hasExtendableVFPtr())
3318	HasVtordispSet.insert(Ptr: BaseDecl);
3319	}
3320	return;
3321	}
3322
3323	// If any of our bases need a vtordisp for this type, so do we. Check our
3324	// direct bases for vtordisp requirements.
3325	for (const CXXBaseSpecifier &Base : RD->bases()) {
3326	const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
3327	const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
3328	for (const auto &bi : Layout.getVBaseOffsetsMap())
3329	if (bi.second.hasVtorDisp())
3330	HasVtordispSet.insert(bi.first);
3331	}
3332	// We don't introduce any additional vtordisps if either:
3333	// * A user declared constructor or destructor aren't declared.
3334	// * #pragma vtordisp(0) or the /vd0 flag are in use.
3335	if ((!RD->hasUserDeclaredConstructor() && !RD->hasUserDeclaredDestructor()) ||
3336	RD->getMSVtorDispMode() == MSVtorDispMode::Never)
3337	return;
3338	// /vd1 or #pragma vtordisp(1): Try to guess based on whether we think it's
3339	// possible for a partially constructed object with virtual base overrides to
3340	// escape a non-trivial constructor.
3341	assert(RD->getMSVtorDispMode() == MSVtorDispMode::ForVBaseOverride);
3342	// Compute a set of base classes which define methods we override. A virtual
3343	// base in this set will require a vtordisp. A virtual base that transitively
3344	// contains one of these bases as a non-virtual base will also require a
3345	// vtordisp.
3346	llvm::SmallPtrSet<const CXXMethodDecl *, 8> Work;
3347	llvm::SmallPtrSet<const CXXRecordDecl *, 2> BasesWithOverriddenMethods;
3348	// Seed the working set with our non-destructor, non-pure virtual methods.
3349	for (const CXXMethodDecl *MD : RD->methods())
3350	if (MicrosoftVTableContext::hasVtableSlot(MD) &&
3351	!isa<CXXDestructorDecl>(Val: MD) && !MD->isPureVirtual())
3352	Work.insert(Ptr: MD);
3353	while (!Work.empty()) {
3354	const CXXMethodDecl *MD = *Work.begin();
3355	auto MethodRange = MD->overridden_methods();
3356	// If a virtual method has no-overrides it lives in its parent's vtable.
3357	if (MethodRange.begin() == MethodRange.end())
3358	BasesWithOverriddenMethods.insert(Ptr: MD->getParent());
3359	else
3360	Work.insert_range(R&: MethodRange);
3361	// We've finished processing this element, remove it from the working set.
3362	Work.erase(Ptr: MD);
3363	}
3364	// For each of our virtual bases, check if it is in the set of overridden
3365	// bases or if it transitively contains a non-virtual base that is.
3366	for (const CXXBaseSpecifier &Base : RD->vbases()) {
3367	const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
3368	if (!HasVtordispSet.count(Ptr: BaseDecl) &&
3369	RequiresVtordisp(BasesWithOverriddenMethods, RD: BaseDecl))
3370	HasVtordispSet.insert(Ptr: BaseDecl);
3371	}
3372	}
3373
3374	/// getASTRecordLayout - Get or compute information about the layout of the
3375	/// specified record (struct/union/class), which indicates its size and field
3376	/// position information.
3377	const ASTRecordLayout &
3378	ASTContext::getASTRecordLayout(const RecordDecl *D) const {
3379	// These asserts test different things. A record has a definition
3380	// as soon as we begin to parse the definition. That definition is
3381	// not a complete definition (which is what isDefinition() tests)
3382	// until we *finish* parsing the definition.
3383
3384	if (D->hasExternalLexicalStorage() && !D->getDefinition())
3385	getExternalSource()->CompleteType(const_cast<RecordDecl*>(D));
3386	// Complete the redecl chain (if necessary).
3387	(void)D->getMostRecentDecl();
3388
3389	D = D->getDefinition();
3390	assert(D && "Cannot get layout of forward declarations!");
3391	assert(!D->isInvalidDecl() && "Cannot get layout of invalid decl!");
3392	assert(D->isCompleteDefinition() && "Cannot layout type before complete!");
3393
3394	// Look up this layout, if already laid out, return what we have.
3395	// Note that we can't save a reference to the entry because this function
3396	// is recursive.
3397	const ASTRecordLayout *Entry = ASTRecordLayouts[D];
3398	if (Entry) return *Entry;
3399
3400	const ASTRecordLayout *NewEntry = nullptr;
3401
3402	if (isMsLayout(Context: *this)) {
3403	if (const auto *RD = dyn_cast<CXXRecordDecl>(Val: D)) {
3404	EmptySubobjectMap EmptySubobjects(*this, RD);
3405	MicrosoftRecordLayoutBuilder Builder(*this, &EmptySubobjects);
3406	Builder.cxxLayout(RD);
3407	NewEntry = new (*this) ASTRecordLayout(
3408	*this, Builder.Size, Builder.Alignment, Builder.Alignment,
3409	Builder.Alignment, Builder.RequiredAlignment, Builder.HasOwnVFPtr,
3410	Builder.HasOwnVFPtr || Builder.PrimaryBase, Builder.VBPtrOffset,
3411	Builder.DataSize, Builder.FieldOffsets, Builder.NonVirtualSize,
3412	Builder.Alignment, Builder.Alignment, CharUnits::Zero(),
3413	Builder.PrimaryBase, false, Builder.SharedVBPtrBase,
3414	Builder.EndsWithZeroSizedObject, Builder.LeadsWithZeroSizedBase,
3415	Builder.Bases, Builder.VBases);
3416	} else {
3417	MicrosoftRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3418	Builder.layout(RD: D);
3419	NewEntry = new (*this) ASTRecordLayout(
3420	*this, Builder.Size, Builder.Alignment, Builder.Alignment,
3421	Builder.Alignment, Builder.RequiredAlignment, Builder.Size,
3422	Builder.FieldOffsets);
3423	}
3424	} else {
3425	if (const auto *RD = dyn_cast<CXXRecordDecl>(Val: D)) {
3426	EmptySubobjectMap EmptySubobjects(*this, RD);
3427	ItaniumRecordLayoutBuilder Builder(*this, &EmptySubobjects);
3428	Builder.Layout(RD);
3429
3430	// In certain situations, we are allowed to lay out objects in the
3431	// tail-padding of base classes. This is ABI-dependent.
3432	// FIXME: this should be stored in the record layout.
3433	bool skipTailPadding =
3434	mustSkipTailPadding(ABI: getTargetInfo().getCXXABI(), RD);
3435
3436	// FIXME: This should be done in FinalizeLayout.
3437	CharUnits DataSize =
3438	skipTailPadding ? Builder.getSize() : Builder.getDataSize();
3439	CharUnits NonVirtualSize =
3440	skipTailPadding ? DataSize : Builder.NonVirtualSize;
3441	NewEntry = new (*this) ASTRecordLayout(
3442	*this, Builder.getSize(), Builder.Alignment,
3443	Builder.PreferredAlignment, Builder.UnadjustedAlignment,
3444	/*RequiredAlignment : used by MS-ABI)*/
3445	Builder.Alignment, Builder.HasOwnVFPtr, RD->isDynamicClass(),
3446	CharUnits::fromQuantity(Quantity: -1), DataSize, Builder.FieldOffsets,
3447	NonVirtualSize, Builder.NonVirtualAlignment,
3448	Builder.PreferredNVAlignment,
3449	EmptySubobjects.SizeOfLargestEmptySubobject, Builder.PrimaryBase,
3450	Builder.PrimaryBaseIsVirtual, nullptr, false, false, Builder.Bases,
3451	Builder.VBases);
3452	} else {
3453	ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3454	Builder.Layout(D);
3455
3456	NewEntry = new (*this) ASTRecordLayout(
3457	*this, Builder.getSize(), Builder.Alignment,
3458	Builder.PreferredAlignment, Builder.UnadjustedAlignment,
3459	/*RequiredAlignment : used by MS-ABI)*/
3460	Builder.Alignment, Builder.getSize(), Builder.FieldOffsets);
3461	}
3462	}
3463
3464	ASTRecordLayouts[D] = NewEntry;
3465
3466	if (getLangOpts().DumpRecordLayouts) {
3467	llvm::outs() << "\n*** Dumping AST Record Layout\n";
3468	DumpRecordLayout(RD: D, OS&: llvm::outs(), Simple: getLangOpts().DumpRecordLayoutsSimple);
3469	}
3470
3471	return *NewEntry;
3472	}
3473
3474	const CXXMethodDecl *ASTContext::getCurrentKeyFunction(const CXXRecordDecl *RD) {
3475	if (!getTargetInfo().getCXXABI().hasKeyFunctions())
3476	return nullptr;
3477
3478	assert(RD->getDefinition() && "Cannot get key function for forward decl!");
3479	RD = RD->getDefinition();
3480
3481	// Beware:
3482	// 1) computing the key function might trigger deserialization, which might
3483	// invalidate iterators into KeyFunctions
3484	// 2) 'get' on the LazyDeclPtr might also trigger deserialization and
3485	// invalidate the LazyDeclPtr within the map itself
3486	LazyDeclPtr Entry = KeyFunctions[RD];
3487	const Decl *Result =
3488	Entry ? Entry.get(Source: getExternalSource()) : computeKeyFunction(Context&: *this, RD);
3489
3490	// Store it back if it changed.
3491	if (Entry.isOffset() || Entry.isValid() != bool(Result))
3492	KeyFunctions[RD] = const_cast<Decl*>(Result);
3493
3494	return cast_or_null<CXXMethodDecl>(Val: Result);
3495	}
3496
3497	void ASTContext::setNonKeyFunction(const CXXMethodDecl *Method) {
3498	assert(Method == Method->getFirstDecl() &&
3499	"not working with method declaration from class definition");
3500
3501	// Look up the cache entry. Since we're working with the first
3502	// declaration, its parent must be the class definition, which is
3503	// the correct key for the KeyFunctions hash.
3504	const auto &Map = KeyFunctions;
3505	auto I = Map.find(Val: Method->getParent());
3506
3507	// If it's not cached, there's nothing to do.
3508	if (I == Map.end()) return;
3509
3510	// If it is cached, check whether it's the target method, and if so,
3511	// remove it from the cache. Note, the call to 'get' might invalidate
3512	// the iterator and the LazyDeclPtr object within the map.
3513	LazyDeclPtr Ptr = I->second;
3514	if (Ptr.get(Source: getExternalSource()) == Method) {
3515	// FIXME: remember that we did this for module / chained PCH state?
3516	KeyFunctions.erase(Val: Method->getParent());
3517	}
3518	}
3519
3520	static uint64_t getFieldOffset(const ASTContext &C, const FieldDecl *FD) {
3521	const ASTRecordLayout &Layout = C.getASTRecordLayout(D: FD->getParent());
3522	return Layout.getFieldOffset(FieldNo: FD->getFieldIndex());
3523	}
3524
3525	uint64_t ASTContext::getFieldOffset(const ValueDecl *VD) const {
3526	uint64_t OffsetInBits;
3527	if (const FieldDecl *FD = dyn_cast<FieldDecl>(Val: VD)) {
3528	OffsetInBits = ::getFieldOffset(C: *this, FD);
3529	} else {
3530	const IndirectFieldDecl *IFD = cast<IndirectFieldDecl>(Val: VD);
3531
3532	OffsetInBits = 0;
3533	for (const NamedDecl *ND : IFD->chain())
3534	OffsetInBits += ::getFieldOffset(C: *this, FD: cast<FieldDecl>(Val: ND));
3535	}
3536
3537	return OffsetInBits;
3538	}
3539
3540	uint64_t ASTContext::lookupFieldBitOffset(const ObjCInterfaceDecl *OID,
3541	const ObjCIvarDecl *Ivar) const {
3542	Ivar = Ivar->getCanonicalDecl();
3543	const ObjCInterfaceDecl *Container = Ivar->getContainingInterface();
3544	const ASTRecordLayout *RL = &getASTObjCInterfaceLayout(D: Container);
3545
3546	// Compute field index.
3547	//
3548	// FIXME: The index here is closely tied to how ASTContext::getObjCLayout is
3549	// implemented. This should be fixed to get the information from the layout
3550	// directly.
3551	unsigned Index = 0;
3552
3553	for (const ObjCIvarDecl *IVD = Container->all_declared_ivar_begin();
3554	IVD; IVD = IVD->getNextIvar()) {
3555	if (Ivar == IVD)
3556	break;
3557	++Index;
3558	}
3559	assert(Index < RL->getFieldCount() && "Ivar is not inside record layout!");
3560
3561	return RL->getFieldOffset(FieldNo: Index);
3562	}
3563
3564	/// getObjCLayout - Get or compute information about the layout of the
3565	/// given interface.
3566	///
3567	/// \param Impl - If given, also include the layout of the interface's
3568	/// implementation. This may differ by including synthesized ivars.
3569	const ASTRecordLayout &
3570	ASTContext::getObjCLayout(const ObjCInterfaceDecl *D) const {
3571	// Retrieve the definition
3572	if (D->hasExternalLexicalStorage() && !D->getDefinition())
3573	getExternalSource()->CompleteType(Class: const_cast<ObjCInterfaceDecl*>(D));
3574	D = D->getDefinition();
3575	assert(D && !D->isInvalidDecl() && D->isThisDeclarationADefinition() &&
3576	"Invalid interface decl!");
3577
3578	// Look up this layout, if already laid out, return what we have.
3579	if (const ASTRecordLayout *Entry = ObjCLayouts[D])
3580	return *Entry;
3581
3582	ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3583	Builder.Layout(D);
3584
3585	const ASTRecordLayout *NewEntry = new (*this) ASTRecordLayout(
3586	*this, Builder.getSize(), Builder.Alignment, Builder.PreferredAlignment,
3587	Builder.UnadjustedAlignment,
3588	/*RequiredAlignment : used by MS-ABI)*/
3589	Builder.Alignment, Builder.getDataSize(), Builder.FieldOffsets);
3590
3591	ObjCLayouts[D] = NewEntry;
3592
3593	return *NewEntry;
3594	}
3595
3596	static void PrintOffset(raw_ostream &OS,
3597	CharUnits Offset, unsigned IndentLevel) {
3598	OS << llvm::format(Fmt: "%10" PRId64 " | ", Vals: (int64_t)Offset.getQuantity());
3599	OS.indent(NumSpaces: IndentLevel * 2);
3600	}
3601
3602	static void PrintBitFieldOffset(raw_ostream &OS, CharUnits Offset,
3603	unsigned Begin, unsigned Width,
3604	unsigned IndentLevel) {
3605	llvm::SmallString<10> Buffer;
3606	{
3607	llvm::raw_svector_ostream BufferOS(Buffer);
3608	BufferOS << Offset.getQuantity() << ':';
3609	if (Width == 0) {
3610	BufferOS << '-';
3611	} else {
3612	BufferOS << Begin << '-' << (Begin + Width - 1);
3613	}
3614	}
3615
3616	OS << llvm::right_justify(Str: Buffer, Width: 10) << " | ";
3617	OS.indent(NumSpaces: IndentLevel * 2);
3618	}
3619
3620	static void PrintIndentNoOffset(raw_ostream &OS, unsigned IndentLevel) {
3621	OS << " | ";
3622	OS.indent(NumSpaces: IndentLevel * 2);
3623	}
3624
3625	static void DumpRecordLayout(raw_ostream &OS, const RecordDecl *RD,
3626	const ASTContext &C,
3627	CharUnits Offset,
3628	unsigned IndentLevel,
3629	const char* Description,
3630	bool PrintSizeInfo,
3631	bool IncludeVirtualBases) {
3632	const ASTRecordLayout &Layout = C.getASTRecordLayout(D: RD);
3633	auto CXXRD = dyn_cast<CXXRecordDecl>(Val: RD);
3634
3635	PrintOffset(OS, Offset, IndentLevel);
3636	OS << C.getTypeDeclType(const_cast<RecordDecl *>(RD));
3637	if (Description)
3638	OS << ' ' << Description;
3639	if (CXXRD && CXXRD->isEmpty())
3640	OS << " (empty)";
3641	OS << '\n';
3642
3643	IndentLevel++;
3644
3645	// Dump bases.
3646	if (CXXRD) {
3647	const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
3648	bool HasOwnVFPtr = Layout.hasOwnVFPtr();
3649	bool HasOwnVBPtr = Layout.hasOwnVBPtr();
3650
3651	// Vtable pointer.
3652	if (CXXRD->isDynamicClass() && !PrimaryBase && !isMsLayout(Context: C)) {
3653	PrintOffset(OS, Offset, IndentLevel);
3654	OS << '(' << *RD << " vtable pointer)\n";
3655	} else if (HasOwnVFPtr) {
3656	PrintOffset(OS, Offset, IndentLevel);
3657	// vfptr (for Microsoft C++ ABI)
3658	OS << '(' << *RD << " vftable pointer)\n";
3659	}
3660
3661	// Collect nvbases.
3662	SmallVector<const CXXRecordDecl *, 4> Bases;
3663	for (const CXXBaseSpecifier &Base : CXXRD->bases()) {
3664	assert(!Base.getType()->isDependentType() &&
3665	"Cannot layout class with dependent bases.");
3666	if (!Base.isVirtual())
3667	Bases.push_back(Elt: Base.getType()->getAsCXXRecordDecl());
3668	}
3669
3670	// Sort nvbases by offset.
3671	llvm::stable_sort(
3672	Range&: Bases, C: [&](const CXXRecordDecl *L, const CXXRecordDecl *R) {
3673	return Layout.getBaseClassOffset(Base: L) < Layout.getBaseClassOffset(Base: R);
3674	});
3675
3676	// Dump (non-virtual) bases
3677	for (const CXXRecordDecl *Base : Bases) {
3678	CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base);
3679	DumpRecordLayout(OS, Base, C, BaseOffset, IndentLevel,
3680	Base == PrimaryBase ? "(primary base)" : "(base)",
3681	/*PrintSizeInfo=*/false,
3682	/*IncludeVirtualBases=*/false);
3683	}
3684
3685	// vbptr (for Microsoft C++ ABI)
3686	if (HasOwnVBPtr) {
3687	PrintOffset(OS, Offset: Offset + Layout.getVBPtrOffset(), IndentLevel);
3688	OS << '(' << *RD << " vbtable pointer)\n";
3689	}
3690	}
3691
3692	// Dump fields.
3693	for (const FieldDecl *Field : RD->fields()) {
3694	uint64_t LocalFieldOffsetInBits =
3695	Layout.getFieldOffset(FieldNo: Field->getFieldIndex());
3696	CharUnits FieldOffset =
3697	Offset + C.toCharUnitsFromBits(BitSize: LocalFieldOffsetInBits);
3698
3699	// Recursively dump fields of record type.
3700	if (auto RT = Field->getType()->getAs<RecordType>()) {
3701	DumpRecordLayout(OS, RT->getDecl(), C, FieldOffset, IndentLevel,
3702	Field->getName().data(),
3703	/*PrintSizeInfo=*/false,
3704	/*IncludeVirtualBases=*/true);
3705	continue;
3706	}
3707
3708	if (Field->isBitField()) {
3709	uint64_t LocalFieldByteOffsetInBits = C.toBits(CharSize: FieldOffset - Offset);
3710	unsigned Begin = LocalFieldOffsetInBits - LocalFieldByteOffsetInBits;
3711	unsigned Width = Field->getBitWidthValue();
3712	PrintBitFieldOffset(OS, Offset: FieldOffset, Begin, Width, IndentLevel);
3713	} else {
3714	PrintOffset(OS, Offset: FieldOffset, IndentLevel);
3715	}
3716	const QualType &FieldType = C.getLangOpts().DumpRecordLayoutsCanonical
3717	? Field->getType().getCanonicalType()
3718	: Field->getType();
3719	OS << FieldType << ' ' << *Field << '\n';
3720	}
3721
3722	// Dump virtual bases.
3723	if (CXXRD && IncludeVirtualBases) {
3724	const ASTRecordLayout::VBaseOffsetsMapTy &VtorDisps =
3725	Layout.getVBaseOffsetsMap();
3726
3727	for (const CXXBaseSpecifier &Base : CXXRD->vbases()) {
3728	assert(Base.isVirtual() && "Found non-virtual class!");
3729	const CXXRecordDecl *VBase = Base.getType()->getAsCXXRecordDecl();
3730
3731	CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBase);
3732
3733	if (VtorDisps.find(Val: VBase)->second.hasVtorDisp()) {
3734	PrintOffset(OS, Offset: VBaseOffset - CharUnits::fromQuantity(Quantity: 4), IndentLevel);
3735	OS << "(vtordisp for vbase " << *VBase << ")\n";
3736	}
3737
3738	DumpRecordLayout(OS, VBase, C, VBaseOffset, IndentLevel,
3739	VBase == Layout.getPrimaryBase() ?
3740	"(primary virtual base)" : "(virtual base)",
3741	/*PrintSizeInfo=*/false,
3742	/*IncludeVirtualBases=*/false);
3743	}
3744	}
3745
3746	if (!PrintSizeInfo) return;
3747
3748	PrintIndentNoOffset(OS, IndentLevel: IndentLevel - 1);
3749	OS << "[sizeof=" << Layout.getSize().getQuantity();
3750	if (CXXRD && !isMsLayout(Context: C))
3751	OS << ", dsize=" << Layout.getDataSize().getQuantity();
3752	OS << ", align=" << Layout.getAlignment().getQuantity();
3753	if (C.getTargetInfo().defaultsToAIXPowerAlignment())
3754	OS << ", preferredalign=" << Layout.getPreferredAlignment().getQuantity();
3755
3756	if (CXXRD) {
3757	OS << ",\n";
3758	PrintIndentNoOffset(OS, IndentLevel: IndentLevel - 1);
3759	OS << " nvsize=" << Layout.getNonVirtualSize().getQuantity();
3760	OS << ", nvalign=" << Layout.getNonVirtualAlignment().getQuantity();
3761	if (C.getTargetInfo().defaultsToAIXPowerAlignment())
3762	OS << ", preferrednvalign="
3763	<< Layout.getPreferredNVAlignment().getQuantity();
3764	}
3765	OS << "]\n";
3766	}
3767
3768	void ASTContext::DumpRecordLayout(const RecordDecl *RD, raw_ostream &OS,
3769	bool Simple) const {
3770	if (!Simple) {
3771	::DumpRecordLayout(OS, RD, C: *this, Offset: CharUnits(), IndentLevel: 0, Description: nullptr,
3772	/*PrintSizeInfo*/ true,
3773	/*IncludeVirtualBases=*/true);
3774	return;
3775	}
3776
3777	// The "simple" format is designed to be parsed by the
3778	// layout-override testing code. There shouldn't be any external
3779	// uses of this format --- when LLDB overrides a layout, it sets up
3780	// the data structures directly --- so feel free to adjust this as
3781	// you like as long as you also update the rudimentary parser for it
3782	// in libFrontend.
3783
3784	const ASTRecordLayout &Info = getASTRecordLayout(D: RD);
3785	OS << "Type: " << getTypeDeclType(RD) << "\n";
3786	OS << "\nLayout: ";
3787	OS << "<ASTRecordLayout\n";
3788	OS << " Size:" << toBits(CharSize: Info.getSize()) << "\n";
3789	if (!isMsLayout(Context: *this))
3790	OS << " DataSize:" << toBits(CharSize: Info.getDataSize()) << "\n";
3791	OS << " Alignment:" << toBits(CharSize: Info.getAlignment()) << "\n";
3792	if (Target->defaultsToAIXPowerAlignment())
3793	OS << " PreferredAlignment:" << toBits(CharSize: Info.getPreferredAlignment())
3794	<< "\n";
3795	if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(Val: RD)) {
3796	OS << " BaseOffsets: [";
3797	const CXXRecordDecl *Base = nullptr;
3798	for (auto I : CXXRD->bases()) {
3799	if (I.isVirtual())
3800	continue;
3801	if (Base)
3802	OS << ", ";
3803	Base = I.getType()->getAsCXXRecordDecl();
3804	OS << Info.CXXInfo->BaseOffsets[Base].getQuantity();
3805	}
3806	OS << "]>\n";
3807	OS << " VBaseOffsets: [";
3808	const CXXRecordDecl *VBase = nullptr;
3809	for (auto I : CXXRD->vbases()) {
3810	if (VBase)
3811	OS << ", ";
3812	VBase = I.getType()->getAsCXXRecordDecl();
3813	OS << Info.CXXInfo->VBaseOffsets[VBase].VBaseOffset.getQuantity();
3814	}
3815	OS << "]>\n";
3816	}
3817	OS << " FieldOffsets: [";
3818	for (unsigned i = 0, e = Info.getFieldCount(); i != e; ++i) {
3819	if (i)
3820	OS << ", ";
3821	OS << Info.getFieldOffset(FieldNo: i);
3822	}
3823	OS << "]>\n";
3824	}
3825