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