Coverage Report

Created: 2021-01-19 06:58

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/AST/RecordLayoutBuilder.cpp
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//=== RecordLayoutBuilder.cpp - Helper class for building record layouts ---==//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/ASTDiagnostic.h"
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#include "clang/AST/Attr.h"
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#include "clang/AST/CXXInheritance.h"
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#include "clang/AST/Decl.h"
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#include "clang/AST/DeclCXX.h"
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#include "clang/AST/DeclObjC.h"
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#include "clang/AST/Expr.h"
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#include "clang/AST/VTableBuilder.h"
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#include "clang/AST/RecordLayout.h"
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#include "clang/Basic/TargetInfo.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/Support/Format.h"
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#include "llvm/Support/MathExtras.h"
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24
using namespace clang;
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namespace {
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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 { };
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/// class C : A, B { };
34
///
35
/// The BaseSubobjectInfo graph for C will have three BaseSubobjectInfo
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/// instances, one for B and two for A.
37
///
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/// If a base is virtual, it will only have one BaseSubobjectInfo allocated.
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struct BaseSubobjectInfo {
40
  /// Class - The class for this base info.
41
  const CXXRecordDecl *Class;
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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
318k
  ExternalLayout() : Size(0), Align(0) {}
62
63
  /// Overall record size in bits.
64
  uint64_t Size;
65
66
  /// Overall record alignment in bits.
67
  uint64_t Align;
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;
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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
18.7k
  uint64_t getExternalFieldOffset(const FieldDecl *FD) {
81
18.7k
    assert(FieldOffsets.count(FD) &&
82
18.7k
           "Field does not have an external offset");
83
18.7k
    return FieldOffsets[FD];
84
18.7k
  }
85
86
3.96k
  bool getExternalNVBaseOffset(const CXXRecordDecl *RD, CharUnits &BaseOffset) {
87
3.96k
    auto Known = BaseOffsets.find(RD);
88
3.96k
    if (Known == BaseOffsets.end())
89
10
      return false;
90
3.95k
    BaseOffset = Known->second;
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3.95k
    return true;
92
3.95k
  }
93
94
23
  bool getExternalVBaseOffset(const CXXRecordDecl *RD, CharUnits &BaseOffset) {
95
23
    auto Known = VirtualBaseOffsets.find(RD);
96
23
    if (Known == VirtualBaseOffsets.end())
97
11
      return false;
98
12
    BaseOffset = Known->second;
99
12
    return true;
100
12
  }
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
1.50M
  bool AnyEmptySubobjectsBeyondOffset(CharUnits Offset) const {
139
1.50M
    return Offset <= MaxEmptyClassOffset;
140
1.50M
  }
141
142
  CharUnits
143
144k
  getFieldOffset(const ASTRecordLayout &Layout, unsigned FieldNo) const {
144
144k
    uint64_t FieldOffset = Layout.getFieldOffset(FieldNo);
145
144k
    assert(FieldOffset % CharWidth == 0 &&
146
144k
           "Field offset not at char boundary!");
147
148
144k
    return Context.toCharUnitsFromBits(FieldOffset);
149
144k
  }
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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
186k
  : Context(Context), CharWidth(Context.getCharWidth()), Class(Class) {
172
186k
      ComputeEmptySubobjectSizes();
173
186k
  }
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
186k
void EmptySubobjectMap::ComputeEmptySubobjectSizes() {
188
  // Check the bases.
189
43.2k
  for (const CXXBaseSpecifier &Base : Class->bases()) {
190
43.2k
    const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
191
192
43.2k
    CharUnits EmptySize;
193
43.2k
    const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
194
43.2k
    if (BaseDecl->isEmpty()) {
195
      // If the class decl is empty, get its size.
196
23.9k
      EmptySize = Layout.getSize();
197
19.2k
    } else {
198
      // Otherwise, we get the largest empty subobject for the decl.
199
19.2k
      EmptySize = Layout.getSizeOfLargestEmptySubobject();
200
19.2k
    }
201
202
43.2k
    if (EmptySize > SizeOfLargestEmptySubobject)
203
26.5k
      SizeOfLargestEmptySubobject = EmptySize;
204
43.2k
  }
205
206
  // Check the fields.
207
311k
  for (const FieldDecl *FD : Class->fields()) {
208
311k
    const RecordType *RT =
209
311k
        Context.getBaseElementType(FD->getType())->getAs<RecordType>();
210
211
    // We only care about record types.
212
311k
    if (!RT)
213
254k
      continue;
214
215
56.6k
    CharUnits EmptySize;
216
56.6k
    const CXXRecordDecl *MemberDecl = RT->getAsCXXRecordDecl();
217
56.6k
    const ASTRecordLayout &Layout = Context.getASTRecordLayout(MemberDecl);
218
56.6k
    if (MemberDecl->isEmpty()) {
219
      // If the class decl is empty, get its size.
220
890
      EmptySize = Layout.getSize();
221
55.7k
    } else {
222
      // Otherwise, we get the largest empty subobject for the decl.
223
55.7k
      EmptySize = Layout.getSizeOfLargestEmptySubobject();
224
55.7k
    }
225
226
56.6k
    if (EmptySize > SizeOfLargestEmptySubobject)
227
4.20k
      SizeOfLargestEmptySubobject = EmptySize;
228
56.6k
  }
229
186k
}
230
231
bool
232
EmptySubobjectMap::CanPlaceSubobjectAtOffset(const CXXRecordDecl *RD,
233
1.11M
                                             CharUnits Offset) const {
234
  // We only need to check empty bases.
235
1.11M
  if (!RD->isEmpty())
236
572k
    return true;
237
238
539k
  EmptyClassOffsetsMapTy::const_iterator I = EmptyClassOffsets.find(Offset);
239
539k
  if (I == EmptyClassOffsets.end())
240
537k
    return true;
241
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1.88k
  const ClassVectorTy &Classes = I->second;
243
1.88k
  if (llvm::find(Classes, RD) == Classes.end())
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1.73k
    return true;
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  // There is already an empty class of the same type at this offset.
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154
  return false;
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154
}
249
250
void EmptySubobjectMap::AddSubobjectAtOffset(const CXXRecordDecl *RD,
251
1.09M
                                             CharUnits Offset) {
252
  // We only care about empty bases.
253
1.09M
  if (!RD->isEmpty())
254
551k
    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
539k
  ClassVectorTy &Classes = EmptyClassOffsets[Offset];
259
539k
  if (llvm::is_contained(Classes, RD))
260
1
    return;
261
262
539k
  Classes.push_back(RD);
263
264
  // Update the empty class offset.
265
539k
  if (Offset > MaxEmptyClassOffset)
266
181
    MaxEmptyClassOffset = Offset;
267
539k
}
268
269
bool
270
EmptySubobjectMap::CanPlaceBaseSubobjectAtOffset(const BaseSubobjectInfo *Info,
271
1.06M
                                                 CharUnits Offset) {
272
  // We don't have to keep looking past the maximum offset that's known to
273
  // contain an empty class.
274
1.06M
  if (!AnyEmptySubobjectsBeyondOffset(Offset))
275
588
    return true;
276
277
1.06M
  if (!CanPlaceSubobjectAtOffset(Info->Class, Offset))
278
103
    return false;
279
280
  // Traverse all non-virtual bases.
281
1.06M
  const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
282
1.03M
  for (const BaseSubobjectInfo *Base : Info->Bases) {
283
1.03M
    if (Base->IsVirtual)
284
139
      continue;
285
286
1.03M
    CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
287
288
1.03M
    if (!CanPlaceBaseSubobjectAtOffset(Base, BaseOffset))
289
77
      return false;
290
1.03M
  }
291
292
1.06M
  if (Info->PrimaryVirtualBaseInfo) {
293
24
    BaseSubobjectInfo *PrimaryVirtualBaseInfo = Info->PrimaryVirtualBaseInfo;
294
295
24
    if (Info == PrimaryVirtualBaseInfo->Derived) {
296
24
      if (!CanPlaceBaseSubobjectAtOffset(PrimaryVirtualBaseInfo, Offset))
297
5
        return false;
298
1.06M
    }
299
24
  }
300
301
  // Traverse all member variables.
302
1.06M
  unsigned FieldNo = 0;
303
1.06M
  for (CXXRecordDecl::field_iterator I = Info->Class->field_begin(),
304
1.07M
       E = Info->Class->field_end(); I != E; 
++I, ++FieldNo9.20k
) {
305
9.20k
    if (I->isBitField())
306
4
      continue;
307
308
9.19k
    CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
309
9.19k
    if (!CanPlaceFieldSubobjectAtOffset(*I, FieldOffset))
310
2
      return false;
311
9.19k
  }
312
313
1.06M
  return true;
314
1.06M
}
315
316
void EmptySubobjectMap::UpdateEmptyBaseSubobjects(const BaseSubobjectInfo *Info,
317
                                                  CharUnits Offset,
318
1.06M
                                                  bool PlacingEmptyBase) {
319
1.06M
  if (!PlacingEmptyBase && 
Offset >= SizeOfLargestEmptySubobject532k
) {
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
520
    return;
326
520
  }
327
328
1.06M
  AddSubobjectAtOffset(Info->Class, Offset);
329
330
  // Traverse all non-virtual bases.
331
1.06M
  const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
332
1.03M
  for (const BaseSubobjectInfo *Base : Info->Bases) {
333
1.03M
    if (Base->IsVirtual)
334
134
      continue;
335
336
1.03M
    CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
337
1.03M
    UpdateEmptyBaseSubobjects(Base, BaseOffset, PlacingEmptyBase);
338
1.03M
  }
339
340
1.06M
  if (Info->PrimaryVirtualBaseInfo) {
341
19
    BaseSubobjectInfo *PrimaryVirtualBaseInfo = Info->PrimaryVirtualBaseInfo;
342
343
19
    if (Info == PrimaryVirtualBaseInfo->Derived)
344
19
      UpdateEmptyBaseSubobjects(PrimaryVirtualBaseInfo, Offset,
345
19
                                PlacingEmptyBase);
346
19
  }
347
348
  // Traverse all member variables.
349
1.06M
  unsigned FieldNo = 0;
350
1.06M
  for (CXXRecordDecl::field_iterator I = Info->Class->field_begin(),
351
1.07M
       E = Info->Class->field_end(); I != E; 
++I, ++FieldNo9.20k
) {
352
9.20k
    if (I->isBitField())
353
4
      continue;
354
355
9.19k
    CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
356
9.19k
    UpdateEmptyFieldSubobjects(*I, FieldOffset, PlacingEmptyBase);
357
9.19k
  }
358
1.06M
}
359
360
bool EmptySubobjectMap::CanPlaceBaseAtOffset(const BaseSubobjectInfo *Info,
361
43.6k
                                             CharUnits Offset) {
362
  // If we know this class doesn't have any empty subobjects we don't need to
363
  // bother checking.
364
43.6k
  if (SizeOfLargestEmptySubobject.isZero())
365
12.0k
    return true;
366
367
31.5k
  if (!CanPlaceBaseSubobjectAtOffset(Info, Offset))
368
105
    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
31.4k
  UpdateEmptyBaseSubobjects(Info, Offset, Info->Class->isEmpty());
373
31.4k
  return true;
374
31.4k
}
375
376
bool
377
EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD,
378
                                                  const CXXRecordDecl *Class,
379
50.6k
                                                  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
50.6k
  if (!AnyEmptySubobjectsBeyondOffset(Offset))
383
672
    return true;
384
385
49.9k
  if (!CanPlaceSubobjectAtOffset(RD, Offset))
386
51
    return false;
387
388
49.9k
  const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
389
390
  // Traverse all non-virtual bases.
391
14.0k
  for (const CXXBaseSpecifier &Base : RD->bases()) {
392
14.0k
    if (Base.isVirtual())
393
28
      continue;
394
395
13.9k
    const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
396
397
13.9k
    CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(BaseDecl);
398
13.9k
    if (!CanPlaceFieldSubobjectAtOffset(BaseDecl, Class, BaseOffset))
399
33
      return false;
400
13.9k
  }
401
402
49.8k
  if (RD == Class) {
403
    // This is the most derived class, traverse virtual bases as well.
404
28
    for (const CXXBaseSpecifier &Base : RD->vbases()) {
405
28
      const CXXRecordDecl *VBaseDecl = Base.getType()->getAsCXXRecordDecl();
406
407
28
      CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBaseDecl);
408
28
      if (!CanPlaceFieldSubobjectAtOffset(VBaseDecl, Class, VBaseOffset))
409
1
        return false;
410
28
    }
411
36.5k
  }
412
413
  // Traverse all member variables.
414
49.8k
  unsigned FieldNo = 0;
415
49.8k
  for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
416
148k
       I != E; 
++I, ++FieldNo98.4k
) {
417
98.4k
    if (I->isBitField())
418
193
      continue;
419
420
98.2k
    CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
421
422
98.2k
    if (!CanPlaceFieldSubobjectAtOffset(*I, FieldOffset))
423
10
      return false;
424
98.2k
  }
425
426
49.8k
  return true;
427
49.8k
}
428
429
bool
430
EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD,
431
393k
                                                  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
393k
  if (!AnyEmptySubobjectsBeyondOffset(Offset))
435
249k
    return true;
436
437
143k
  QualType T = FD->getType();
438
143k
  if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
439
36.3k
    return CanPlaceFieldSubobjectAtOffset(RD, RD, Offset);
440
441
  // If we have an array type we need to look at every element.
442
107k
  if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
443
10.4k
    QualType ElemTy = Context.getBaseElementType(AT);
444
10.4k
    const RecordType *RT = ElemTy->getAs<RecordType>();
445
10.4k
    if (!RT)
446
9.20k
      return true;
447
448
1.27k
    const CXXRecordDecl *RD = RT->getAsCXXRecordDecl();
449
1.27k
    const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
450
451
1.27k
    uint64_t NumElements = Context.getConstantArrayElementCount(AT);
452
1.27k
    CharUnits ElementOffset = Offset;
453
1.52k
    for (uint64_t I = 0; I != NumElements; 
++I246
) {
454
      // We don't have to keep looking past the maximum offset that's known to
455
      // contain an empty class.
456
450
      if (!AnyEmptySubobjectsBeyondOffset(ElementOffset))
457
200
        return true;
458
459
250
      if (!CanPlaceFieldSubobjectAtOffset(RD, RD, ElementOffset))
460
4
        return false;
461
462
246
      ElementOffset += Layout.getSize();
463
246
    }
464
1.27k
  }
465
466
97.8k
  return true;
467
107k
}
468
469
bool
470
EmptySubobjectMap::CanPlaceFieldAtOffset(const FieldDecl *FD,
471
285k
                                         CharUnits Offset) {
472
285k
  if (!CanPlaceFieldSubobjectAtOffset(FD, Offset))
473
49
    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
285k
  UpdateEmptyFieldSubobjects(FD, Offset, FD->hasAttr<NoUniqueAddressAttr>());
478
285k
  return true;
479
285k
}
480
481
void EmptySubobjectMap::UpdateEmptyFieldSubobjects(
482
    const CXXRecordDecl *RD, const CXXRecordDecl *Class, CharUnits Offset,
483
72.6k
    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
72.6k
  if (!PlacingOverlappingField && 
Offset >= SizeOfLargestEmptySubobject72.4k
)
495
43.8k
    return;
496
497
28.8k
  AddSubobjectAtOffset(RD, Offset);
498
499
28.8k
  const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
500
501
  // Traverse all non-virtual bases.
502
12.6k
  for (const CXXBaseSpecifier &Base : RD->bases()) {
503
12.6k
    if (Base.isVirtual())
504
26
      continue;
505
506
12.6k
    const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
507
508
12.6k
    CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(BaseDecl);
509
12.6k
    UpdateEmptyFieldSubobjects(BaseDecl, Class, BaseOffset,
510
12.6k
                               PlacingOverlappingField);
511
12.6k
  }
512
513
28.8k
  if (RD == Class) {
514
    // This is the most derived class, traverse virtual bases as well.
515
26
    for (const CXXBaseSpecifier &Base : RD->vbases()) {
516
26
      const CXXRecordDecl *VBaseDecl = Base.getType()->getAsCXXRecordDecl();
517
518
26
      CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBaseDecl);
519
26
      UpdateEmptyFieldSubobjects(VBaseDecl, Class, VBaseOffset,
520
26
                                 PlacingOverlappingField);
521
26
    }
522
16.5k
  }
523
524
  // Traverse all member variables.
525
28.8k
  unsigned FieldNo = 0;
526
28.8k
  for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
527
56.7k
       I != E; 
++I, ++FieldNo27.9k
) {
528
27.9k
    if (I->isBitField())
529
2
      continue;
530
531
27.9k
    CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
532
533
27.9k
    UpdateEmptyFieldSubobjects(*I, FieldOffset, PlacingOverlappingField);
534
27.9k
  }
535
28.8k
}
536
537
void EmptySubobjectMap::UpdateEmptyFieldSubobjects(
538
322k
    const FieldDecl *FD, CharUnits Offset, bool PlacingOverlappingField) {
539
322k
  QualType T = FD->getType();
540
322k
  if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl()) {
541
59.9k
    UpdateEmptyFieldSubobjects(RD, RD, Offset, PlacingOverlappingField);
542
59.9k
    return;
543
59.9k
  }
544
545
  // If we have an array type we need to update every element.
546
262k
  if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
547
23.3k
    QualType ElemTy = Context.getBaseElementType(AT);
548
23.3k
    const RecordType *RT = ElemTy->getAs<RecordType>();
549
23.3k
    if (!RT)
550
21.2k
      return;
551
552
2.09k
    const CXXRecordDecl *RD = RT->getAsCXXRecordDecl();
553
2.09k
    const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
554
555
2.09k
    uint64_t NumElements = Context.getConstantArrayElementCount(AT);
556
2.09k
    CharUnits ElementOffset = Offset;
557
558
2.13k
    for (uint64_t I = 0; I != NumElements; 
++I49
) {
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
1.08k
      if (!PlacingOverlappingField &&
565
1.06k
          ElementOffset >= SizeOfLargestEmptySubobject)
566
1.03k
        return;
567
568
49
      UpdateEmptyFieldSubobjects(RD, RD, ElementOffset,
569
49
                                 PlacingOverlappingField);
570
49
      ElementOffset += Layout.getSize();
571
49
    }
572
2.09k
  }
573
262k
}
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
  unsigned UseExternalLayout : 1;
606
607
  /// Whether we need to infer alignment, even when we have an
608
  /// externally-provided layout.
609
  unsigned InferAlignment : 1;
610
611
  /// Packed - Whether the record is packed or not.
612
  unsigned Packed : 1;
613
614
  unsigned IsUnion : 1;
615
616
  unsigned IsMac68kAlign : 1;
617
618
  unsigned IsNaturalAlign : 1;
619
620
  unsigned IsMsStruct : 1;
621
622
  /// UnfilledBitsInLastUnit - If the last field laid out was a bitfield,
623
  /// this contains the number of bits in the last unit that can be used for
624
  /// an adjacent bitfield if necessary.  The unit in question is usually
625
  /// a byte, but larger units are used if IsMsStruct.
626
  unsigned char UnfilledBitsInLastUnit;
627
628
  /// LastBitfieldStorageUnitSize - If IsMsStruct, represents the size of the
629
  /// storage unit of the previous field if it was a bitfield.
630
  unsigned char LastBitfieldStorageUnitSize;
631
632
  /// MaxFieldAlignment - The maximum allowed field alignment. This is set by
633
  /// #pragma pack.
634
  CharUnits MaxFieldAlignment;
635
636
  /// DataSize - The data size of the record being laid out.
637
  uint64_t DataSize;
638
639
  CharUnits NonVirtualSize;
640
  CharUnits NonVirtualAlignment;
641
  CharUnits PreferredNVAlignment;
642
643
  /// If we've laid out a field but not included its tail padding in Size yet,
644
  /// this is the size up to the end of that field.
645
  CharUnits PaddedFieldSize;
646
647
  /// PrimaryBase - the primary base class (if one exists) of the class
648
  /// we're laying out.
649
  const CXXRecordDecl *PrimaryBase;
650
651
  /// PrimaryBaseIsVirtual - Whether the primary base of the class we're laying
652
  /// out is virtual.
653
  bool PrimaryBaseIsVirtual;
654
655
  /// HasOwnVFPtr - Whether the class provides its own vtable/vftbl
656
  /// pointer, as opposed to inheriting one from a primary base class.
657
  bool HasOwnVFPtr;
658
659
  /// the flag of field offset changing due to packed attribute.
660
  bool HasPackedField;
661
662
  /// HandledFirstNonOverlappingEmptyField - An auxiliary field used for AIX.
663
  /// When there are OverlappingEmptyFields existing in the aggregate, the
664
  /// flag shows if the following first non-empty or empty-but-non-overlapping
665
  /// field has been handled, if any.
666
  bool HandledFirstNonOverlappingEmptyField;
667
668
  typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
669
670
  /// Bases - base classes and their offsets in the record.
671
  BaseOffsetsMapTy Bases;
672
673
  // VBases - virtual base classes and their offsets in the record.
674
  ASTRecordLayout::VBaseOffsetsMapTy VBases;
675
676
  /// IndirectPrimaryBases - Virtual base classes, direct or indirect, that are
677
  /// primary base classes for some other direct or indirect base class.
678
  CXXIndirectPrimaryBaseSet IndirectPrimaryBases;
679
680
  /// FirstNearlyEmptyVBase - The first nearly empty virtual base class in
681
  /// inheritance graph order. Used for determining the primary base class.
682
  const CXXRecordDecl *FirstNearlyEmptyVBase;
683
684
  /// VisitedVirtualBases - A set of all the visited virtual bases, used to
685
  /// avoid visiting virtual bases more than once.
686
  llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBases;
687
688
  /// Valid if UseExternalLayout is true.
689
  ExternalLayout External;
690
691
  ItaniumRecordLayoutBuilder(const ASTContext &Context,
692
                             EmptySubobjectMap *EmptySubobjects)
693
      : Context(Context), EmptySubobjects(EmptySubobjects), Size(0),
694
        Alignment(CharUnits::One()), PreferredAlignment(CharUnits::One()),
695
        UnpackedAlignment(CharUnits::One()),
696
        UnadjustedAlignment(CharUnits::One()), UseExternalLayout(false),
697
        InferAlignment(false), Packed(false), IsUnion(false),
698
        IsMac68kAlign(false),
699
        IsNaturalAlign(!Context.getTargetInfo().getTriple().isOSAIX()),
700
        IsMsStruct(false), UnfilledBitsInLastUnit(0),
701
        LastBitfieldStorageUnitSize(0), MaxFieldAlignment(CharUnits::Zero()),
702
        DataSize(0), NonVirtualSize(CharUnits::Zero()),
703
        NonVirtualAlignment(CharUnits::One()),
704
        PreferredNVAlignment(CharUnits::One()),
705
        PaddedFieldSize(CharUnits::Zero()), PrimaryBase(nullptr),
706
        PrimaryBaseIsVirtual(false), HasOwnVFPtr(false), HasPackedField(false),
707
        HandledFirstNonOverlappingEmptyField(false),
708
312k
        FirstNearlyEmptyVBase(nullptr) {}
709
710
  void Layout(const RecordDecl *D);
711
  void Layout(const CXXRecordDecl *D);
712
  void Layout(const ObjCInterfaceDecl *D);
713
714
  void LayoutFields(const RecordDecl *D);
715
  void LayoutField(const FieldDecl *D, bool InsertExtraPadding);
716
  void LayoutWideBitField(uint64_t FieldSize, uint64_t StorageUnitSize,
717
                          bool FieldPacked, const FieldDecl *D);
718
  void LayoutBitField(const FieldDecl *D);
719
720
0
  TargetCXXABI getCXXABI() const {
721
0
    return Context.getTargetInfo().getCXXABI();
722
0
  }
723
724
  /// BaseSubobjectInfoAllocator - Allocator for BaseSubobjectInfo objects.
725
  llvm::SpecificBumpPtrAllocator<BaseSubobjectInfo> BaseSubobjectInfoAllocator;
726
727
  typedef llvm::DenseMap<const CXXRecordDecl *, BaseSubobjectInfo *>
728
    BaseSubobjectInfoMapTy;
729
730
  /// VirtualBaseInfo - Map from all the (direct or indirect) virtual bases
731
  /// of the class we're laying out to their base subobject info.
732
  BaseSubobjectInfoMapTy VirtualBaseInfo;
733
734
  /// NonVirtualBaseInfo - Map from all the direct non-virtual bases of the
735
  /// class we're laying out to their base subobject info.
736
  BaseSubobjectInfoMapTy NonVirtualBaseInfo;
737
738
  /// ComputeBaseSubobjectInfo - Compute the base subobject information for the
739
  /// bases of the given class.
740
  void ComputeBaseSubobjectInfo(const CXXRecordDecl *RD);
741
742
  /// ComputeBaseSubobjectInfo - Compute the base subobject information for a
743
  /// single class and all of its base classes.
744
  BaseSubobjectInfo *ComputeBaseSubobjectInfo(const CXXRecordDecl *RD,
745
                                              bool IsVirtual,
746
                                              BaseSubobjectInfo *Derived);
747
748
  /// DeterminePrimaryBase - Determine the primary base of the given class.
749
  void DeterminePrimaryBase(const CXXRecordDecl *RD);
750
751
  void SelectPrimaryVBase(const CXXRecordDecl *RD);
752
753
  void EnsureVTablePointerAlignment(CharUnits UnpackedBaseAlign);
754
755
  /// LayoutNonVirtualBases - Determines the primary base class (if any) and
756
  /// lays it out. Will then proceed to lay out all non-virtual base clasess.
757
  void LayoutNonVirtualBases(const CXXRecordDecl *RD);
758
759
  /// LayoutNonVirtualBase - Lays out a single non-virtual base.
760
  void LayoutNonVirtualBase(const BaseSubobjectInfo *Base);
761
762
  void AddPrimaryVirtualBaseOffsets(const BaseSubobjectInfo *Info,
763
                                    CharUnits Offset);
764
765
  /// LayoutVirtualBases - Lays out all the virtual bases.
766
  void LayoutVirtualBases(const CXXRecordDecl *RD,
767
                          const CXXRecordDecl *MostDerivedClass);
768
769
  /// LayoutVirtualBase - Lays out a single virtual base.
770
  void LayoutVirtualBase(const BaseSubobjectInfo *Base);
771
772
  /// LayoutBase - Will lay out a base and return the offset where it was
773
  /// placed, in chars.
774
  CharUnits LayoutBase(const BaseSubobjectInfo *Base);
775
776
  /// InitializeLayout - Initialize record layout for the given record decl.
777
  void InitializeLayout(const Decl *D);
778
779
  /// FinishLayout - Finalize record layout. Adjust record size based on the
780
  /// alignment.
781
  void FinishLayout(const NamedDecl *D);
782
783
  void UpdateAlignment(CharUnits NewAlignment, CharUnits UnpackedNewAlignment,
784
                       CharUnits PreferredAlignment);
785
18.8k
  void UpdateAlignment(CharUnits NewAlignment, CharUnits UnpackedNewAlignment) {
786
18.8k
    UpdateAlignment(NewAlignment, UnpackedNewAlignment, NewAlignment);
787
18.8k
  }
788
8.07k
  void UpdateAlignment(CharUnits NewAlignment) {
789
8.07k
    UpdateAlignment(NewAlignment, NewAlignment, NewAlignment);
790
8.07k
  }
791
792
  /// Retrieve the externally-supplied field offset for the given
793
  /// field.
794
  ///
795
  /// \param Field The field whose offset is being queried.
796
  /// \param ComputedOffset The offset that we've computed for this field.
797
  uint64_t updateExternalFieldOffset(const FieldDecl *Field,
798
                                     uint64_t ComputedOffset);
799
800
  void CheckFieldPadding(uint64_t Offset, uint64_t UnpaddedOffset,
801
                          uint64_t UnpackedOffset, unsigned UnpackedAlign,
802
                          bool isPacked, const FieldDecl *D);
803
804
  DiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID);
805
806
591k
  CharUnits getSize() const {
807
591k
    assert(Size % Context.getCharWidth() == 0);
808
591k
    return Context.toCharUnitsFromBits(Size);
809
591k
  }
810
2.76M
  uint64_t getSizeInBits() const { return Size; }
811
812
102k
  void setSize(CharUnits NewSize) { Size = Context.toBits(NewSize); }
813
1.43M
  void setSize(uint64_t NewSize) { Size = NewSize; }
814
815
0
  CharUnits getAligment() const { return Alignment; }
816
817
890k
  CharUnits getDataSize() const {
818
890k
    assert(DataSize % Context.getCharWidth() == 0);
819
890k
    return Context.toCharUnitsFromBits(DataSize);
820
890k
  }
821
1.67M
  uint64_t getDataSizeInBits() const { return DataSize; }
822
823
767k
  void setDataSize(CharUnits NewSize) { DataSize = Context.toBits(NewSize); }
824
65.6k
  void setDataSize(uint64_t NewSize) { DataSize = NewSize; }
825
826
  ItaniumRecordLayoutBuilder(const ItaniumRecordLayoutBuilder &) = delete;
827
  void operator=(const ItaniumRecordLayoutBuilder &) = delete;
828
};
829
} // end anonymous namespace
830
831
1.43k
void ItaniumRecordLayoutBuilder::SelectPrimaryVBase(const CXXRecordDecl *RD) {
832
999
  for (const auto &I : RD->bases()) {
833
999
    assert(!I.getType()->isDependentType() &&
834
999
           "Cannot layout class with dependent bases.");
835
836
999
    const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
837
838
    // Check if this is a nearly empty virtual base.
839
999
    if (I.isVirtual() && 
Context.isNearlyEmpty(Base)684
) {
840
      // If it's not an indirect primary base, then we've found our primary
841
      // base.
842
201
      if (!IndirectPrimaryBases.count(Base)) {
843
198
        PrimaryBase = Base;
844
198
        PrimaryBaseIsVirtual = true;
845
198
        return;
846
198
      }
847
848
      // Is this the first nearly empty virtual base?
849
3
      if (!FirstNearlyEmptyVBase)
850
3
        FirstNearlyEmptyVBase = Base;
851
3
    }
852
853
801
    SelectPrimaryVBase(Base);
854
801
    if (PrimaryBase)
855
8
      return;
856
801
  }
857
1.43k
}
858
859
/// DeterminePrimaryBase - Determine the primary base of the given class.
860
186k
void ItaniumRecordLayoutBuilder::DeterminePrimaryBase(const CXXRecordDecl *RD) {
861
  // If the class isn't dynamic, it won't have a primary base.
862
186k
  if (!RD->isDynamicClass())
863
174k
    return;
864
865
  // Compute all the primary virtual bases for all of our direct and
866
  // indirect bases, and record all their primary virtual base classes.
867
11.9k
  RD->getIndirectPrimaryBases(IndirectPrimaryBases);
868
869
  // If the record has a dynamic base class, attempt to choose a primary base
870
  // class. It is the first (in direct base class order) non-virtual dynamic
871
  // base class, if one exists.
872
8.88k
  for (const auto &I : RD->bases()) {
873
    // Ignore virtual bases.
874
8.88k
    if (I.isVirtual())
875
710
      continue;
876
877
8.17k
    const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
878
879
8.17k
    if (Base->isDynamicClass()) {
880
      // We found it.
881
8.01k
      PrimaryBase = Base;
882
8.01k
      PrimaryBaseIsVirtual = false;
883
8.01k
      return;
884
8.01k
    }
885
8.17k
  }
886
887
  // Under the Itanium ABI, if there is no non-virtual primary base class,
888
  // try to compute the primary virtual base.  The primary virtual base is
889
  // the first nearly empty virtual base that is not an indirect primary
890
  // virtual base class, if one exists.
891
3.91k
  if (RD->getNumVBases() != 0) {
892
638
    SelectPrimaryVBase(RD);
893
638
    if (PrimaryBase)
894
198
      return;
895
3.71k
  }
896
897
  // Otherwise, it is the first indirect primary base class, if one exists.
898
3.71k
  if (FirstNearlyEmptyVBase) {
899
2
    PrimaryBase = FirstNearlyEmptyVBase;
900
2
    PrimaryBaseIsVirtual = true;
901
2
    return;
902
2
  }
903
904
3.71k
  assert(!PrimaryBase && "Should not get here with a primary base!");
905
3.71k
}
906
907
BaseSubobjectInfo *ItaniumRecordLayoutBuilder::ComputeBaseSubobjectInfo(
908
1.08M
    const CXXRecordDecl *RD, bool IsVirtual, BaseSubobjectInfo *Derived) {
909
1.08M
  BaseSubobjectInfo *Info;
910
911
1.08M
  if (IsVirtual) {
912
    // Check if we already have info about this virtual base.
913
1.40k
    BaseSubobjectInfo *&InfoSlot = VirtualBaseInfo[RD];
914
1.40k
    if (InfoSlot) {
915
233
      assert(InfoSlot->Class == RD && "Wrong class for virtual base info!");
916
233
      return InfoSlot;
917
233
    }
918
919
    // We don't, create it.
920
1.17k
    InfoSlot = new (BaseSubobjectInfoAllocator.Allocate()) BaseSubobjectInfo;
921
1.17k
    Info = InfoSlot;
922
1.07M
  } else {
923
1.07M
    Info = new (BaseSubobjectInfoAllocator.Allocate()) BaseSubobjectInfo;
924
1.07M
  }
925
926
1.08M
  Info->Class = RD;
927
1.08M
  Info->IsVirtual = IsVirtual;
928
1.08M
  Info->Derived = nullptr;
929
1.08M
  Info->PrimaryVirtualBaseInfo = nullptr;
930
931
1.08M
  const CXXRecordDecl *PrimaryVirtualBase = nullptr;
932
1.08M
  BaseSubobjectInfo *PrimaryVirtualBaseInfo = nullptr;
933
934
  // Check if this base has a primary virtual base.
935
1.08M
  if (RD->getNumVBases()) {
936
637
    const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
937
637
    if (Layout.isPrimaryBaseVirtual()) {
938
      // This base does have a primary virtual base.
939
173
      PrimaryVirtualBase = Layout.getPrimaryBase();
940
173
      assert(PrimaryVirtualBase && "Didn't have a primary virtual base!");
941
942
      // Now check if we have base subobject info about this primary base.
943
173
      PrimaryVirtualBaseInfo = VirtualBaseInfo.lookup(PrimaryVirtualBase);
944
945
173
      if (PrimaryVirtualBaseInfo) {
946
55
        if (PrimaryVirtualBaseInfo->Derived) {
947
          // We did have info about this primary base, and it turns out that it
948
          // has already been claimed as a primary virtual base for another
949
          // base.
950
33
          PrimaryVirtualBase = nullptr;
951
22
        } else {
952
          // We can claim this base as our primary base.
953
22
          Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
954
22
          PrimaryVirtualBaseInfo->Derived = Info;
955
22
        }
956
55
      }
957
173
    }
958
637
  }
959
960
  // Now go through all direct bases.
961
1.03M
  for (const auto &I : RD->bases()) {
962
1.03M
    bool IsVirtual = I.isVirtual();
963
964
1.03M
    const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
965
966
1.03M
    Info->Bases.push_back(ComputeBaseSubobjectInfo(BaseDecl, IsVirtual, Info));
967
1.03M
  }
968
969
1.08M
  if (PrimaryVirtualBase && 
!PrimaryVirtualBaseInfo140
) {
970
    // Traversing the bases must have created the base info for our primary
971
    // virtual base.
972
118
    PrimaryVirtualBaseInfo = VirtualBaseInfo.lookup(PrimaryVirtualBase);
973
118
    assert(PrimaryVirtualBaseInfo &&
974
118
           "Did not create a primary virtual base!");
975
976
    // Claim the primary virtual base as our primary virtual base.
977
118
    Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
978
118
    PrimaryVirtualBaseInfo->Derived = Info;
979
118
  }
980
981
1.08M
  return Info;
982
1.08M
}
983
984
void ItaniumRecordLayoutBuilder::ComputeBaseSubobjectInfo(
985
186k
    const CXXRecordDecl *RD) {
986
43.2k
  for (const auto &I : RD->bases()) {
987
43.2k
    bool IsVirtual = I.isVirtual();
988
989
43.2k
    const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
990
991
    // Compute the base subobject info for this base.
992
43.2k
    BaseSubobjectInfo *Info = ComputeBaseSubobjectInfo(BaseDecl, IsVirtual,
993
43.2k
                                                       nullptr);
994
995
43.2k
    if (IsVirtual) {
996
      // ComputeBaseInfo has already added this base for us.
997
753
      assert(VirtualBaseInfo.count(BaseDecl) &&
998
753
             "Did not add virtual base!");
999
42.4k
    } else {
1000
      // Add the base info to the map of non-virtual bases.
1001
42.4k
      assert(!NonVirtualBaseInfo.count(BaseDecl) &&
1002
42.4k
             "Non-virtual base already exists!");
1003
42.4k
      NonVirtualBaseInfo.insert(std::make_pair(BaseDecl, Info));
1004
42.4k
    }
1005
43.2k
  }
1006
186k
}
1007
1008
void ItaniumRecordLayoutBuilder::EnsureVTablePointerAlignment(
1009
3.71k
    CharUnits UnpackedBaseAlign) {
1010
3.70k
  CharUnits BaseAlign = Packed ? 
CharUnits::One()2
: UnpackedBaseAlign;
1011
1012
  // The maximum field alignment overrides base align.
1013
3.71k
  if (!MaxFieldAlignment.isZero()) {
1014
5
    BaseAlign = std::min(BaseAlign, MaxFieldAlignment);
1015
5
    UnpackedBaseAlign = std::min(UnpackedBaseAlign, MaxFieldAlignment);
1016
5
  }
1017
1018
  // Round up the current record size to pointer alignment.
1019
3.71k
  setSize(getSize().alignTo(BaseAlign));
1020
1021
  // Update the alignment.
1022
3.71k
  UpdateAlignment(BaseAlign, UnpackedBaseAlign, BaseAlign);
1023
3.71k
}
1024
1025
void ItaniumRecordLayoutBuilder::LayoutNonVirtualBases(
1026
186k
    const CXXRecordDecl *RD) {
1027
  // Then, determine the primary base class.
1028
186k
  DeterminePrimaryBase(RD);
1029
1030
  // Compute base subobject info.
1031
186k
  ComputeBaseSubobjectInfo(RD);
1032
1033
  // If we have a primary base class, lay it out.
1034
186k
  if (PrimaryBase) {
1035
8.21k
    if (PrimaryBaseIsVirtual) {
1036
      // If the primary virtual base was a primary virtual base of some other
1037
      // base class we'll have to steal it.
1038
200
      BaseSubobjectInfo *PrimaryBaseInfo = VirtualBaseInfo.lookup(PrimaryBase);
1039
200
      PrimaryBaseInfo->Derived = nullptr;
1040
1041
      // We have a virtual primary base, insert it as an indirect primary base.
1042
200
      IndirectPrimaryBases.insert(PrimaryBase);
1043
1044
200
      assert(!VisitedVirtualBases.count(PrimaryBase) &&
1045
200
             "vbase already visited!");
1046
200
      VisitedVirtualBases.insert(PrimaryBase);
1047
1048
200
      LayoutVirtualBase(PrimaryBaseInfo);
1049
8.01k
    } else {
1050
8.01k
      BaseSubobjectInfo *PrimaryBaseInfo =
1051
8.01k
        NonVirtualBaseInfo.lookup(PrimaryBase);
1052
8.01k
      assert(PrimaryBaseInfo &&
1053
8.01k
             "Did not find base info for non-virtual primary base!");
1054
1055
8.01k
      LayoutNonVirtualBase(PrimaryBaseInfo);
1056
8.01k
    }
1057
1058
  // If this class needs a vtable/vf-table and didn't get one from a
1059
  // primary base, add it in now.
1060
178k
  } else if (RD->isDynamicClass()) {
1061
3.71k
    assert(DataSize == 0 && "Vtable pointer must be at offset zero!");
1062
3.71k
    CharUnits PtrWidth =
1063
3.71k
      Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
1064
3.71k
    CharUnits PtrAlign =
1065
3.71k
      Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(0));
1066
3.71k
    EnsureVTablePointerAlignment(PtrAlign);
1067
3.71k
    HasOwnVFPtr = true;
1068
1069
3.71k
    assert(!IsUnion && "Unions cannot be dynamic classes.");
1070
3.71k
    HandledFirstNonOverlappingEmptyField = true;
1071
1072
3.71k
    setSize(getSize() + PtrWidth);
1073
3.71k
    setDataSize(getSize());
1074
3.71k
  }
1075
1076
  // Now lay out the non-virtual bases.
1077
43.2k
  for (const auto &I : RD->bases()) {
1078
1079
    // Ignore virtual bases.
1080
43.2k
    if (I.isVirtual())
1081
753
      continue;
1082
1083
42.4k
    const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
1084
1085
    // Skip the primary base, because we've already laid it out.  The
1086
    // !PrimaryBaseIsVirtual check is required because we might have a
1087
    // non-virtual base of the same type as a primary virtual base.
1088
42.4k
    if (BaseDecl == PrimaryBase && 
!PrimaryBaseIsVirtual8.01k
)
1089
8.01k
      continue;
1090
1091
    // Lay out the base.
1092
34.4k
    BaseSubobjectInfo *BaseInfo = NonVirtualBaseInfo.lookup(BaseDecl);
1093
34.4k
    assert(BaseInfo && "Did not find base info for non-virtual base!");
1094
1095
34.4k
    LayoutNonVirtualBase(BaseInfo);
1096
34.4k
  }
1097
186k
}
1098
1099
void ItaniumRecordLayoutBuilder::LayoutNonVirtualBase(
1100
42.4k
    const BaseSubobjectInfo *Base) {
1101
  // Layout the base.
1102
42.4k
  CharUnits Offset = LayoutBase(Base);
1103
1104
  // Add its base class offset.
1105
42.4k
  assert(!Bases.count(Base->Class) && "base offset already exists!");
1106
42.4k
  Bases.insert(std::make_pair(Base->Class, Offset));
1107
1108
42.4k
  AddPrimaryVirtualBaseOffsets(Base, Offset);
1109
42.4k
}
1110
1111
void ItaniumRecordLayoutBuilder::AddPrimaryVirtualBaseOffsets(
1112
43.8k
    const BaseSubobjectInfo *Info, CharUnits Offset) {
1113
  // This base isn't interesting, it has no virtual bases.
1114
43.8k
  if (!Info->Class->getNumVBases())
1115
43.2k
    return;
1116
1117
  // First, check if we have a virtual primary base to add offsets for.
1118
637
  if (Info->PrimaryVirtualBaseInfo) {
1119
140
    assert(Info->PrimaryVirtualBaseInfo->IsVirtual &&
1120
140
           "Primary virtual base is not virtual!");
1121
140
    if (Info->PrimaryVirtualBaseInfo->Derived == Info) {
1122
      // Add the offset.
1123
137
      assert(!VBases.count(Info->PrimaryVirtualBaseInfo->Class) &&
1124
137
             "primary vbase offset already exists!");
1125
137
      VBases.insert(std::make_pair(Info->PrimaryVirtualBaseInfo->Class,
1126
137
                                   ASTRecordLayout::VBaseInfo(Offset, false)));
1127
1128
      // Traverse the primary virtual base.
1129
137
      AddPrimaryVirtualBaseOffsets(Info->PrimaryVirtualBaseInfo, Offset);
1130
137
    }
1131
140
  }
1132
1133
  // Now go through all direct non-virtual bases.
1134
637
  const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
1135
887
  for (const BaseSubobjectInfo *Base : Info->Bases) {
1136
887
    if (Base->IsVirtual)
1137
654
      continue;
1138
1139
233
    CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
1140
233
    AddPrimaryVirtualBaseOffsets(Base, BaseOffset);
1141
233
  }
1142
637
}
1143
1144
void ItaniumRecordLayoutBuilder::LayoutVirtualBases(
1145
187k
    const CXXRecordDecl *RD, const CXXRecordDecl *MostDerivedClass) {
1146
187k
  const CXXRecordDecl *PrimaryBase;
1147
187k
  bool PrimaryBaseIsVirtual;
1148
1149
187k
  if (MostDerivedClass == RD) {
1150
186k
    PrimaryBase = this->PrimaryBase;
1151
186k
    PrimaryBaseIsVirtual = this->PrimaryBaseIsVirtual;
1152
641
  } else {
1153
641
    const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1154
641
    PrimaryBase = Layout.getPrimaryBase();
1155
641
    PrimaryBaseIsVirtual = Layout.isPrimaryBaseVirtual();
1156
641
  }
1157
1158
44.1k
  for (const CXXBaseSpecifier &Base : RD->bases()) {
1159
44.1k
    assert(!Base.getType()->isDependentType() &&
1160
44.1k
           "Cannot layout class with dependent bases.");
1161
1162
44.1k
    const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1163
1164
44.1k
    if (Base.isVirtual()) {
1165
1.41k
      if (PrimaryBase != BaseDecl || 
!PrimaryBaseIsVirtual359
) {
1166
1.05k
        bool IndirectPrimaryBase = IndirectPrimaryBases.count(BaseDecl);
1167
1168
        // Only lay out the virtual base if it's not an indirect primary base.
1169
1.05k
        if (!IndirectPrimaryBase) {
1170
          // Only visit virtual bases once.
1171
1.01k
          if (!VisitedVirtualBases.insert(BaseDecl).second)
1172
180
            continue;
1173
1174
837
          const BaseSubobjectInfo *BaseInfo = VirtualBaseInfo.lookup(BaseDecl);
1175
837
          assert(BaseInfo && "Did not find virtual base info!");
1176
837
          LayoutVirtualBase(BaseInfo);
1177
837
        }
1178
1.05k
      }
1179
1.41k
    }
1180
1181
43.9k
    if (!BaseDecl->getNumVBases()) {
1182
      // This base isn't interesting since it doesn't have any virtual bases.
1183
43.2k
      continue;
1184
43.2k
    }
1185
1186
641
    LayoutVirtualBases(BaseDecl, MostDerivedClass);
1187
641
  }
1188
187k
}
1189
1190
void ItaniumRecordLayoutBuilder::LayoutVirtualBase(
1191
1.03k
    const BaseSubobjectInfo *Base) {
1192
1.03k
  assert(!Base->Derived && "Trying to lay out a primary virtual base!");
1193
1194
  // Layout the base.
1195
1.03k
  CharUnits Offset = LayoutBase(Base);
1196
1197
  // Add its base class offset.
1198
1.03k
  assert(!VBases.count(Base->Class) && "vbase offset already exists!");
1199
1.03k
  VBases.insert(std::make_pair(Base->Class,
1200
1.03k
                       ASTRecordLayout::VBaseInfo(Offset, false)));
1201
1202
1.03k
  AddPrimaryVirtualBaseOffsets(Base, Offset);
1203
1.03k
}
1204
1205
CharUnits
1206
43.4k
ItaniumRecordLayoutBuilder::LayoutBase(const BaseSubobjectInfo *Base) {
1207
43.4k
  assert(!IsUnion && "Unions cannot have base classes.");
1208
1209
43.4k
  const ASTRecordLayout &Layout = Context.getASTRecordLayout(Base->Class);
1210
43.4k
  CharUnits Offset;
1211
1212
  // Query the external layout to see if it provides an offset.
1213
43.4k
  bool HasExternalLayout = false;
1214
43.4k
  if (UseExternalLayout) {
1215
3.98k
    if (Base->IsVirtual)
1216
20
      HasExternalLayout = External.getExternalVBaseOffset(Base->Class, Offset);
1217
3.96k
    else
1218
3.96k
      HasExternalLayout = External.getExternalNVBaseOffset(Base->Class, Offset);
1219
3.98k
  }
1220
1221
86.9k
  auto getBaseOrPreferredBaseAlignFromUnpacked = [&](CharUnits UnpackedAlign) {
1222
    // Clang <= 6 incorrectly applied the 'packed' attribute to base classes.
1223
    // Per GCC's documentation, it only applies to non-static data members.
1224
86.9k
    return (Packed && 
(90
(Context.getLangOpts().getClangABICompat() <=
1225
90
                        LangOptions::ClangABI::Ver6) ||
1226
76
                       Context.getTargetInfo().getTriple().isPS4() ||
1227
72
                       Context.getTargetInfo().getTriple().isOSAIX()))
1228
34
               ? CharUnits::One()
1229
86.9k
               : UnpackedAlign;
1230
86.9k
  };
1231
1232
43.4k
  CharUnits UnpackedBaseAlign = Layout.getNonVirtualAlignment();
1233
43.4k
  CharUnits UnpackedPreferredBaseAlign = Layout.getPreferredNVAlignment();
1234
43.4k
  CharUnits BaseAlign =
1235
43.4k
      getBaseOrPreferredBaseAlignFromUnpacked(UnpackedBaseAlign);
1236
43.4k
  CharUnits PreferredBaseAlign =
1237
43.4k
      getBaseOrPreferredBaseAlignFromUnpacked(UnpackedPreferredBaseAlign);
1238
1239
43.4k
  const bool DefaultsToAIXPowerAlignment =
1240
43.4k
      Context.getTargetInfo().defaultsToAIXPowerAlignment();
1241
43.4k
  if (DefaultsToAIXPowerAlignment) {
1242
    // AIX `power` alignment does not apply the preferred alignment for
1243
    // non-union classes if the source of the alignment (the current base in
1244
    // this context) follows introduction of the first subobject with
1245
    // exclusively allocated space or zero-extent array.
1246
46
    if (!Base->Class->isEmpty() && 
!HandledFirstNonOverlappingEmptyField40
) {
1247
      // By handling a base class that is not empty, we're handling the
1248
      // "first (inherited) member".
1249
24
      HandledFirstNonOverlappingEmptyField = true;
1250
22
    } else if (!IsNaturalAlign) {
1251
20
      UnpackedPreferredBaseAlign = UnpackedBaseAlign;
1252
20
      PreferredBaseAlign = BaseAlign;
1253
20
    }
1254
46
  }
1255
1256
43.4k
  CharUnits UnpackedAlignTo = !DefaultsToAIXPowerAlignment
1257
43.4k
                                  ? UnpackedBaseAlign
1258
46
                                  : UnpackedPreferredBaseAlign;
1259
  // If we have an empty base class, try to place it at offset 0.
1260
43.4k
  if (Base->Class->isEmpty() &&
1261
24.0k
      (!HasExternalLayout || 
Offset == CharUnits::Zero()2.28k
) &&
1262
24.0k
      EmptySubobjects->CanPlaceBaseAtOffset(Base, CharUnits::Zero())) {
1263
23.9k
    setSize(std::max(getSize(), Layout.getSize()));
1264
23.9k
    UpdateAlignment(BaseAlign, UnpackedAlignTo, PreferredBaseAlign);
1265
1266
23.9k
    return CharUnits::Zero();
1267
23.9k
  }
1268
1269
  // The maximum field alignment overrides the base align/(AIX-only) preferred
1270
  // base align.
1271
19.5k
  if (!MaxFieldAlignment.isZero()) {
1272
25
    BaseAlign = std::min(BaseAlign, MaxFieldAlignment);
1273
25
    PreferredBaseAlign = std::min(PreferredBaseAlign, MaxFieldAlignment);
1274
25
    UnpackedAlignTo = std::min(UnpackedAlignTo, MaxFieldAlignment);
1275
25
  }
1276
1277
19.5k
  CharUnits AlignTo =
1278
19.5k
      !DefaultsToAIXPowerAlignment ? BaseAlign : 
PreferredBaseAlign40
;
1279
19.5k
  if (!HasExternalLayout) {
1280
    // Round up the current record size to the base's alignment boundary.
1281
17.8k
    Offset = getDataSize().alignTo(AlignTo);
1282
1283
    // Try to place the base.
1284
17.9k
    while (!EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset))
1285
36
      Offset += AlignTo;
1286
1.68k
  } else {
1287
1.68k
    bool Allowed = EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset);
1288
1.68k
    (void)Allowed;
1289
1.68k
    assert(Allowed && "Base subobject externally placed at overlapping offset");
1290
1291
1.68k
    if (InferAlignment && 
Offset < getDataSize().alignTo(AlignTo)807
) {
1292
      // The externally-supplied base offset is before the base offset we
1293
      // computed. Assume that the structure is packed.
1294
0
      Alignment = CharUnits::One();
1295
0
      InferAlignment = false;
1296
0
    }
1297
1.68k
  }
1298
1299
19.5k
  if (!Base->Class->isEmpty()) {
1300
    // Update the data size.
1301
19.4k
    setDataSize(Offset + Layout.getNonVirtualSize());
1302
1303
19.4k
    setSize(std::max(getSize(), getDataSize()));
1304
19.4k
  } else
1305
69
    setSize(std::max(getSize(), Offset + Layout.getSize()));
1306
1307
  // Remember max struct/class alignment.
1308
19.5k
  UpdateAlignment(BaseAlign, UnpackedAlignTo, PreferredBaseAlign);
1309
1310
19.5k
  return Offset;
1311
19.5k
}
1312
1313
312k
void ItaniumRecordLayoutBuilder::InitializeLayout(const Decl *D) {
1314
312k
  if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
1315
307k
    IsUnion = RD->isUnion();
1316
307k
    IsMsStruct = RD->isMsStruct(Context);
1317
307k
  }
1318
1319
312k
  Packed = D->hasAttr<PackedAttr>();
1320
1321
  // Honor the default struct packing maximum alignment flag.
1322
312k
  if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct) {
1323
2
    MaxFieldAlignment = CharUnits::fromQuantity(DefaultMaxFieldAlignment);
1324
2
  }
1325
1326
  // mac68k alignment supersedes maximum field alignment and attribute aligned,
1327
  // and forces all structures to have 2-byte alignment. The IBM docs on it
1328
  // allude to additional (more complicated) semantics, especially with regard
1329
  // to bit-fields, but gcc appears not to follow that.
1330
312k
  if (D->hasAttr<AlignMac68kAttr>()) {
1331
12
    assert(
1332
12
        !D->hasAttr<AlignNaturalAttr>() &&
1333
12
        "Having both mac68k and natural alignment on a decl is not allowed.");
1334
12
    IsMac68kAlign = true;
1335
12
    MaxFieldAlignment = CharUnits::fromQuantity(2);
1336
12
    Alignment = CharUnits::fromQuantity(2);
1337
12
    PreferredAlignment = CharUnits::fromQuantity(2);
1338
312k
  } else {
1339
312k
    if (D->hasAttr<AlignNaturalAttr>())
1340
26
      IsNaturalAlign = true;
1341
1342
312k
    if (const MaxFieldAlignmentAttr *MFAA = D->getAttr<MaxFieldAlignmentAttr>())
1343
53.4k
      MaxFieldAlignment = Context.toCharUnitsFromBits(MFAA->getAlignment());
1344
1345
312k
    if (unsigned MaxAlign = D->getMaxAlignment())
1346
3.95k
      UpdateAlignment(Context.toCharUnitsFromBits(MaxAlign));
1347
312k
  }
1348
1349
312k
  HandledFirstNonOverlappingEmptyField =
1350
312k
      !Context.getTargetInfo().defaultsToAIXPowerAlignment() || 
IsNaturalAlign254
;
1351
1352
  // If there is an external AST source, ask it for the various offsets.
1353
312k
  if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
1354
307k
    if (ExternalASTSource *Source = Context.getExternalSource()) {
1355
110k
      UseExternalLayout = Source->layoutRecordType(
1356
110k
          RD, External.Size, External.Align, External.FieldOffsets,
1357
110k
          External.BaseOffsets, External.VirtualBaseOffsets);
1358
1359
      // Update based on external alignment.
1360
110k
      if (UseExternalLayout) {
1361
12.8k
        if (External.Align > 0) {
1362
8.42k
          Alignment = Context.toCharUnitsFromBits(External.Align);
1363
8.42k
          PreferredAlignment = Context.toCharUnitsFromBits(External.Align);
1364
4.43k
        } else {
1365
          // The external source didn't have alignment information; infer it.
1366
4.43k
          InferAlignment = true;
1367
4.43k
        }
1368
12.8k
      }
1369
110k
    }
1370
312k
}
1371
1372
120k
void ItaniumRecordLayoutBuilder::Layout(const RecordDecl *D) {
1373
120k
  InitializeLayout(D);
1374
120k
  LayoutFields(D);
1375
1376
  // Finally, round the size of the total struct up to the alignment of the
1377
  // struct itself.
1378
120k
  FinishLayout(D);
1379
120k
}
1380
1381
186k
void ItaniumRecordLayoutBuilder::Layout(const CXXRecordDecl *RD) {
1382
186k
  InitializeLayout(RD);
1383
1384
  // Lay out the vtable and the non-virtual bases.
1385
186k
  LayoutNonVirtualBases(RD);
1386
1387
186k
  LayoutFields(RD);
1388
1389
186k
  NonVirtualSize = Context.toCharUnitsFromBits(
1390
186k
      llvm::alignTo(getSizeInBits(), Context.getTargetInfo().getCharAlign()));
1391
186k
  NonVirtualAlignment = Alignment;
1392
186k
  PreferredNVAlignment = PreferredAlignment;
1393
1394
  // Lay out the virtual bases and add the primary virtual base offsets.
1395
186k
  LayoutVirtualBases(RD, RD);
1396
1397
  // Finally, round the size of the total struct up to the alignment
1398
  // of the struct itself.
1399
186k
  FinishLayout(RD);
1400
1401
186k
#ifndef NDEBUG
1402
  // Check that we have base offsets for all bases.
1403
43.2k
  for (const CXXBaseSpecifier &Base : RD->bases()) {
1404
43.2k
    if (Base.isVirtual())
1405
753
      continue;
1406
1407
42.4k
    const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1408
1409
42.4k
    assert(Bases.count(BaseDecl) && "Did not find base offset!");
1410
42.4k
  }
1411
1412
  // And all virtual bases.
1413
1.17k
  for (const CXXBaseSpecifier &Base : RD->vbases()) {
1414
1.17k
    const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1415
1416
1.17k
    assert(VBases.count(BaseDecl) && "Did not find base offset!");
1417
1.17k
  }
1418
186k
#endif
1419
186k
}
1420
1421
5.31k
void ItaniumRecordLayoutBuilder::Layout(const ObjCInterfaceDecl *D) {
1422
5.31k
  if (ObjCInterfaceDecl *SD = D->getSuperClass()) {
1423
4.09k
    const ASTRecordLayout &SL = Context.getASTObjCInterfaceLayout(SD);
1424
1425
4.09k
    UpdateAlignment(SL.getAlignment());
1426
1427
    // We start laying out ivars not at the end of the superclass
1428
    // structure, but at the next byte following the last field.
1429
4.09k
    setDataSize(SL.getDataSize());
1430
4.09k
    setSize(getDataSize());
1431
4.09k
  }
1432
1433
5.31k
  InitializeLayout(D);
1434
  // Layout each ivar sequentially.
1435
12.5k
  for (const ObjCIvarDecl *IVD = D->all_declared_ivar_begin(); IVD;
1436
7.22k
       IVD = IVD->getNextIvar())
1437
7.22k
    LayoutField(IVD, false);
1438
1439
  // Finally, round the size of the total struct up to the alignment of the
1440
  // struct itself.
1441
5.31k
  FinishLayout(D);
1442
5.31k
}
1443
1444
307k
void ItaniumRecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
1445
  // Layout each field, for now, just sequentially, respecting alignment.  In
1446
  // the future, this will need to be tweakable by targets.
1447
307k
  bool InsertExtraPadding = D->mayInsertExtraPadding(/*EmitRemark=*/true);
1448
307k
  bool HasFlexibleArrayMember = D->hasFlexibleArrayMember();
1449
1.10M
  for (auto I = D->field_begin(), End = D->field_end(); I != End; 
++I798k
) {
1450
798k
    auto Next(I);
1451
798k
    ++Next;
1452
798k
    LayoutField(*I,
1453
798k
                InsertExtraPadding && 
(42
Next != End42
||
!HasFlexibleArrayMember16
));
1454
798k
  }
1455
307k
}
1456
1457
// Rounds the specified size to have it a multiple of the char size.
1458
static uint64_t
1459
roundUpSizeToCharAlignment(uint64_t Size,
1460
116
                           const ASTContext &Context) {
1461
116
  uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
1462
116
  return llvm::alignTo(Size, CharAlignment);
1463
116
}
1464
1465
void ItaniumRecordLayoutBuilder::LayoutWideBitField(uint64_t FieldSize,
1466
                                                    uint64_t StorageUnitSize,
1467
                                                    bool FieldPacked,
1468
32
                                                    const FieldDecl *D) {
1469
32
  assert(Context.getLangOpts().CPlusPlus &&
1470
32
         "Can only have wide bit-fields in C++!");
1471
1472
  // Itanium C++ ABI 2.4:
1473
  //   If sizeof(T)*8 < n, let T' be the largest integral POD type with
1474
  //   sizeof(T')*8 <= n.
1475
1476
32
  QualType IntegralPODTypes[] = {
1477
32
    Context.UnsignedCharTy, Context.UnsignedShortTy, Context.UnsignedIntTy,
1478
32
    Context.UnsignedLongTy, Context.UnsignedLongLongTy
1479
32
  };
1480
1481
32
  QualType Type;
1482
129
  for (const QualType &QT : IntegralPODTypes) {
1483
129
    uint64_t Size = Context.getTypeSize(QT);
1484
1485
129
    if (Size > FieldSize)
1486
18
      break;
1487
1488
111
    Type = QT;
1489
111
  }
1490
32
  assert(!Type.isNull() && "Did not find a type!");
1491
1492
32
  CharUnits TypeAlign = Context.getTypeAlignInChars(Type);
1493
1494
  // We're not going to use any of the unfilled bits in the last byte.
1495
32
  UnfilledBitsInLastUnit = 0;
1496
32
  LastBitfieldStorageUnitSize = 0;
1497
1498
32
  uint64_t FieldOffset;
1499
32
  uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;
1500
1501
32
  if (IsUnion) {
1502
9
    uint64_t RoundedFieldSize = roundUpSizeToCharAlignment(FieldSize,
1503
9
                                                           Context);
1504
9
    setDataSize(std::max(getDataSizeInBits(), RoundedFieldSize));
1505
9
    FieldOffset = 0;
1506
23
  } else {
1507
    // The bitfield is allocated starting at the next offset aligned
1508
    // appropriately for T', with length n bits.
1509
23
    FieldOffset = llvm::alignTo(getDataSizeInBits(), Context.toBits(TypeAlign));
1510
1511
23
    uint64_t NewSizeInBits = FieldOffset + FieldSize;
1512
1513
23
    setDataSize(
1514
23
        llvm::alignTo(NewSizeInBits, Context.getTargetInfo().getCharAlign()));
1515
23
    UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;
1516
23
  }
1517
1518
  // Place this field at the current location.
1519
32
  FieldOffsets.push_back(FieldOffset);
1520
1521
32
  CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, FieldOffset,
1522
32
                    Context.toBits(TypeAlign), FieldPacked, D);
1523
1524
  // Update the size.
1525
32
  setSize(std::max(getSizeInBits(), getDataSizeInBits()));
1526
1527
  // Remember max struct/class alignment.
1528
32
  UpdateAlignment(TypeAlign);
1529
32
}
1530
1531
18.8k
void ItaniumRecordLayoutBuilder::LayoutBitField(const FieldDecl *D) {
1532
18.8k
  bool FieldPacked = Packed || 
D->hasAttr<PackedAttr>()18.3k
;
1533
18.8k
  uint64_t FieldSize = D->getBitWidthValue(Context);
1534
18.8k
  TypeInfo FieldInfo = Context.getTypeInfo(D->getType());
1535
18.8k
  uint64_t StorageUnitSize = FieldInfo.Width;
1536
18.8k
  unsigned FieldAlign = FieldInfo.Align;
1537
1538
  // UnfilledBitsInLastUnit is the difference between the end of the
1539
  // last allocated bitfield (i.e. the first bit offset available for
1540
  // bitfields) and the end of the current data size in bits (i.e. the
1541
  // first bit offset available for non-bitfields).  The current data
1542
  // size in bits is always a multiple of the char size; additionally,
1543
  // for ms_struct records it's also a multiple of the
1544
  // LastBitfieldStorageUnitSize (if set).
1545
1546
  // The struct-layout algorithm is dictated by the platform ABI,
1547
  // which in principle could use almost any rules it likes.  In
1548
  // practice, UNIXy targets tend to inherit the algorithm described
1549
  // in the System V generic ABI.  The basic bitfield layout rule in
1550
  // System V is to place bitfields at the next available bit offset
1551
  // where the entire bitfield would fit in an aligned storage unit of
1552
  // the declared type; it's okay if an earlier or later non-bitfield
1553
  // is allocated in the same storage unit.  However, some targets
1554
  // (those that !useBitFieldTypeAlignment(), e.g. ARM APCS) don't
1555
  // require this storage unit to be aligned, and therefore always put
1556
  // the bitfield at the next available bit offset.
1557
1558
  // ms_struct basically requests a complete replacement of the
1559
  // platform ABI's struct-layout algorithm, with the high-level goal
1560
  // of duplicating MSVC's layout.  For non-bitfields, this follows
1561
  // the standard algorithm.  The basic bitfield layout rule is to
1562
  // allocate an entire unit of the bitfield's declared type
1563
  // (e.g. 'unsigned long'), then parcel it up among successive
1564
  // bitfields whose declared types have the same size, making a new
1565
  // unit as soon as the last can no longer store the whole value.
1566
  // Since it completely replaces the platform ABI's algorithm,
1567
  // settings like !useBitFieldTypeAlignment() do not apply.
1568
1569
  // A zero-width bitfield forces the use of a new storage unit for
1570
  // later bitfields.  In general, this occurs by rounding up the
1571
  // current size of the struct as if the algorithm were about to
1572
  // place a non-bitfield of the field's formal type.  Usually this
1573
  // does not change the alignment of the struct itself, but it does
1574
  // on some targets (those that useZeroLengthBitfieldAlignment(),
1575
  // e.g. ARM).  In ms_struct layout, zero-width bitfields are
1576
  // ignored unless they follow a non-zero-width bitfield.
1577
1578
  // A field alignment restriction (e.g. from #pragma pack) or
1579
  // specification (e.g. from __attribute__((aligned))) changes the
1580
  // formal alignment of the field.  For System V, this alters the
1581
  // required alignment of the notional storage unit that must contain
1582
  // the bitfield.  For ms_struct, this only affects the placement of
1583
  // new storage units.  In both cases, the effect of #pragma pack is
1584
  // ignored on zero-width bitfields.
1585
1586
  // On System V, a packed field (e.g. from #pragma pack or
1587
  // __attribute__((packed))) always uses the next available bit
1588
  // offset.
1589
1590
  // In an ms_struct struct, the alignment of a fundamental type is
1591
  // always equal to its size.  This is necessary in order to mimic
1592
  // the i386 alignment rules on targets which might not fully align
1593
  // all types (e.g. Darwin PPC32, where alignof(long long) == 4).
1594
1595
  // First, some simple bookkeeping to perform for ms_struct structs.
1596
18.8k
  if (IsMsStruct) {
1597
    // The field alignment for integer types is always the size.
1598
307
    FieldAlign = StorageUnitSize;
1599
1600
    // If the previous field was not a bitfield, or was a bitfield
1601
    // with a different storage unit size, or if this field doesn't fit into
1602
    // the current storage unit, we're done with that storage unit.
1603
307
    if (LastBitfieldStorageUnitSize != StorageUnitSize ||
1604
272
        
UnfilledBitsInLastUnit < FieldSize55
) {
1605
      // Also, ignore zero-length bitfields after non-bitfields.
1606
272
      if (!LastBitfieldStorageUnitSize && 
!FieldSize173
)
1607
93
        FieldAlign = 1;
1608
1609
272
      UnfilledBitsInLastUnit = 0;
1610
272
      LastBitfieldStorageUnitSize = 0;
1611
272
    }
1612
307
  }
1613
1614
  // If the field is wider than its declared type, it follows
1615
  // different rules in all cases.
1616
18.8k
  if (FieldSize > StorageUnitSize) {
1617
32
    LayoutWideBitField(FieldSize, StorageUnitSize, FieldPacked, D);
1618
32
    return;
1619
32
  }
1620
1621
  // Compute the next available bit offset.
1622
18.8k
  uint64_t FieldOffset =
1623
18.6k
    IsUnion ? 
0115
: (getDataSizeInBits() - UnfilledBitsInLastUnit);
1624
1625
  // Handle targets that don't honor bitfield type alignment.
1626
18.8k
  if (!IsMsStruct && 
!Context.getTargetInfo().useBitFieldTypeAlignment()18.4k
) {
1627
    // Some such targets do honor it on zero-width bitfields.
1628
120
    if (FieldSize == 0 &&
1629
57
        Context.getTargetInfo().useZeroLengthBitfieldAlignment()) {
1630
      // The alignment to round up to is the max of the field's natural
1631
      // alignment and a target-specific fixed value (sometimes zero).
1632
55
      unsigned ZeroLengthBitfieldBoundary =
1633
55
        Context.getTargetInfo().getZeroLengthBitfieldBoundary();
1634
55
      FieldAlign = std::max(FieldAlign, ZeroLengthBitfieldBoundary);
1635
1636
    // If that doesn't apply, just ignore the field alignment.
1637
65
    } else {
1638
65
      FieldAlign = 1;
1639
65
    }
1640
120
  }
1641
1642
  // Remember the alignment we would have used if the field were not packed.
1643
18.8k
  unsigned UnpackedFieldAlign = FieldAlign;
1644
1645
  // Ignore the field alignment if the field is packed unless it has zero-size.
1646
18.8k
  if (!IsMsStruct && 
FieldPacked18.4k
&&
FieldSize != 0535
)
1647
520
    FieldAlign = 1;
1648
1649
  // But, if there's an 'aligned' attribute on the field, honor that.
1650
18.8k
  unsigned ExplicitFieldAlign = D->getMaxAlignment();
1651
18.8k
  if (ExplicitFieldAlign) {
1652
158
    FieldAlign = std::max(FieldAlign, ExplicitFieldAlign);
1653
158
    UnpackedFieldAlign = std::max(UnpackedFieldAlign, ExplicitFieldAlign);
1654
158
  }
1655
1656
  // But, if there's a #pragma pack in play, that takes precedent over
1657
  // even the 'aligned' attribute, for non-zero-width bitfields.
1658
18.8k
  unsigned MaxFieldAlignmentInBits = Context.toBits(MaxFieldAlignment);
1659
18.8k
  if (!MaxFieldAlignment.isZero() && 
FieldSize4.84k
) {
1660
4.83k
    UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignmentInBits);
1661
4.83k
    if (FieldPacked)
1662
34
      FieldAlign = UnpackedFieldAlign;
1663
4.80k
    else
1664
4.80k
      FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
1665
4.83k
  }
1666
1667
  // But, ms_struct just ignores all of that in unions, even explicit
1668
  // alignment attributes.
1669
18.8k
  if (IsMsStruct && 
IsUnion307
) {
1670
8
    FieldAlign = UnpackedFieldAlign = 1;
1671
8
  }
1672
1673
  // For purposes of diagnostics, we're going to simultaneously
1674
  // compute the field offsets that we would have used if we weren't
1675
  // adding any alignment padding or if the field weren't packed.
1676
18.8k
  uint64_t UnpaddedFieldOffset = FieldOffset;
1677
18.8k
  uint64_t UnpackedFieldOffset = FieldOffset;
1678
1679
  // Check if we need to add padding to fit the bitfield within an
1680
  // allocation unit with the right size and alignment.  The rules are
1681
  // somewhat different here for ms_struct structs.
1682
18.8k
  if (IsMsStruct) {
1683
    // If it's not a zero-width bitfield, and we can fit the bitfield
1684
    // into the active storage unit (and we haven't already decided to
1685
    // start a new storage unit), just do so, regardless of any other
1686
    // other consideration.  Otherwise, round up to the right alignment.
1687
307
    if (FieldSize == 0 || 
FieldSize > UnfilledBitsInLastUnit199
) {
1688
275
      FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
1689
275
      UnpackedFieldOffset =
1690
275
          llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
1691
275
      UnfilledBitsInLastUnit = 0;
1692
275
    }
1693
1694
18.4k
  } else {
1695
    // #pragma pack, with any value, suppresses the insertion of padding.
1696
18.4k
    bool AllowPadding = MaxFieldAlignment.isZero();
1697
1698
    // Compute the real offset.
1699
18.4k
    if (FieldSize == 0 ||
1700
18.0k
        (AllowPadding &&
1701
13.3k
         (FieldOffset & (FieldAlign - 1)) + FieldSize > StorageUnitSize)) {
1702
543
      FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
1703
17.9k
    } else if (ExplicitFieldAlign &&
1704
128
               (MaxFieldAlignmentInBits == 0 ||
1705
24
                ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
1706
120
               Context.getTargetInfo().useExplicitBitFieldAlignment()) {
1707
      // TODO: figure it out what needs to be done on targets that don't honor
1708
      // bit-field type alignment like ARM APCS ABI.
1709
100
      FieldOffset = llvm::alignTo(FieldOffset, ExplicitFieldAlign);
1710
100
    }
1711
1712
    // Repeat the computation for diagnostic purposes.
1713
18.4k
    if (FieldSize == 0 ||
1714
18.0k
        (AllowPadding &&
1715
13.3k
         (UnpackedFieldOffset & (UnpackedFieldAlign - 1)) + FieldSize >
1716
13.3k
             StorageUnitSize))
1717
601
      UnpackedFieldOffset =
1718
601
          llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
1719
17.8k
    else if (ExplicitFieldAlign &&
1720
123
             (MaxFieldAlignmentInBits == 0 ||
1721
24
              ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
1722
115
             Context.getTargetInfo().useExplicitBitFieldAlignment())
1723
96
      UnpackedFieldOffset =
1724
96
          llvm::alignTo(UnpackedFieldOffset, ExplicitFieldAlign);
1725
18.4k
  }
1726
1727
  // If we're using external layout, give the external layout a chance
1728
  // to override this information.
1729
18.8k
  if (UseExternalLayout)
1730
1.72k
    FieldOffset = updateExternalFieldOffset(D, FieldOffset);
1731
1732
  // Okay, place the bitfield at the calculated offset.
1733
18.8k
  FieldOffsets.push_back(FieldOffset);
1734
1735
  // Bookkeeping:
1736
1737
  // Anonymous members don't affect the overall record alignment,
1738
  // except on targets where they do.
1739
18.8k
  if (!IsMsStruct &&
1740
18.4k
      !Context.getTargetInfo().useZeroLengthBitfieldAlignment() &&
1741
17.4k
      !D->getIdentifier())
1742
1.52k
    FieldAlign = UnpackedFieldAlign = 1;
1743
1744
  // Diagnose differences in layout due to padding or packing.
1745
18.8k
  if (!UseExternalLayout)
1746
17.0k
    CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, UnpackedFieldOffset,
1747
17.0k
                      UnpackedFieldAlign, FieldPacked, D);
1748
1749
  // Update DataSize to include the last byte containing (part of) the bitfield.
1750
1751
  // For unions, this is just a max operation, as usual.
1752
18.8k
  if (IsUnion) {
1753
    // For ms_struct, allocate the entire storage unit --- unless this
1754
    // is a zero-width bitfield, in which case just use a size of 1.
1755
115
    uint64_t RoundedFieldSize;
1756
115
    if (IsMsStruct) {
1757
5
      RoundedFieldSize = (FieldSize ? StorageUnitSize
1758
3
                                    : Context.getTargetInfo().getCharWidth());
1759
1760
      // Otherwise, allocate just the number of bytes required to store
1761
      // the bitfield.
1762
107
    } else {
1763
107
      RoundedFieldSize = roundUpSizeToCharAlignment(FieldSize, Context);
1764
107
    }
1765
115
    setDataSize(std::max(getDataSizeInBits(), RoundedFieldSize));
1766
1767
  // For non-zero-width bitfields in ms_struct structs, allocate a new
1768
  // storage unit if necessary.
1769
18.6k
  } else if (IsMsStruct && 
FieldSize299
) {
1770
    // We should have cleared UnfilledBitsInLastUnit in every case
1771
    // where we changed storage units.
1772
194
    if (!UnfilledBitsInLastUnit) {
1773
162
      setDataSize(FieldOffset + StorageUnitSize);
1774
162
      UnfilledBitsInLastUnit = StorageUnitSize;
1775
162
    }
1776
194
    UnfilledBitsInLastUnit -= FieldSize;
1777
194
    LastBitfieldStorageUnitSize = StorageUnitSize;
1778
1779
    // Otherwise, bump the data size up to include the bitfield,
1780
    // including padding up to char alignment, and then remember how
1781
    // bits we didn't use.
1782
18.4k
  } else {
1783
18.4k
    uint64_t NewSizeInBits = FieldOffset + FieldSize;
1784
18.4k
    uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
1785
18.4k
    setDataSize(llvm::alignTo(NewSizeInBits, CharAlignment));
1786
18.4k
    UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;
1787
1788
    // The only time we can get here for an ms_struct is if this is a
1789
    // zero-width bitfield, which doesn't count as anything for the
1790
    // purposes of unfilled bits.
1791
18.4k
    LastBitfieldStorageUnitSize = 0;
1792
18.4k
  }
1793
1794
  // Update the size.
1795
18.8k
  setSize(std::max(getSizeInBits(), getDataSizeInBits()));
1796
1797
  // Remember max struct/class alignment.
1798
18.8k
  UnadjustedAlignment =
1799
18.8k
      std::max(UnadjustedAlignment, Context.toCharUnitsFromBits(FieldAlign));
1800
18.8k
  UpdateAlignment(Context.toCharUnitsFromBits(FieldAlign),
1801
18.8k
                  Context.toCharUnitsFromBits(UnpackedFieldAlign));
1802
18.8k
}
1803
1804
void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D,
1805
806k
                                             bool InsertExtraPadding) {
1806
806k
  auto *FieldClass = D->getType()->getAsCXXRecordDecl();
1807
806k
  bool PotentiallyOverlapping = D->hasAttr<NoUniqueAddressAttr>() && 
FieldClass123
;
1808
806k
  bool IsOverlappingEmptyField =
1809
806k
      PotentiallyOverlapping && 
FieldClass->isEmpty()113
;
1810
1811
806k
  CharUnits FieldOffset =
1812
806k
      (IsUnion || 
IsOverlappingEmptyField759k
) ?
CharUnits::Zero()47.1k
:
getDataSize()758k
;
1813
1814
806k
  const bool DefaultsToAIXPowerAlignment =
1815
806k
      Context.getTargetInfo().defaultsToAIXPowerAlignment();
1816
806k
  bool FoundFirstNonOverlappingEmptyFieldForAIX = false;
1817
806k
  if (DefaultsToAIXPowerAlignment && 
!HandledFirstNonOverlappingEmptyField304
) {
1818
162
    assert(FieldOffset == CharUnits::Zero() &&
1819
162
           "The first non-overlapping empty field should have been handled.");
1820
1821
162
    if (!IsOverlappingEmptyField) {
1822
154
      FoundFirstNonOverlappingEmptyFieldForAIX = true;
1823
1824
      // We're going to handle the "first member" based on
1825
      // `FoundFirstNonOverlappingEmptyFieldForAIX` during the current
1826
      // invocation of this function; record it as handled for future
1827
      // invocations (except for unions, because the current field does not
1828
      // represent all "firsts").
1829
154
      HandledFirstNonOverlappingEmptyField = !IsUnion;
1830
154
    }
1831
162
  }
1832
1833
806k
  if (D->isBitField()) {
1834
18.8k
    LayoutBitField(D);
1835
18.8k
    return;
1836
18.8k
  }
1837
1838
787k
  uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;
1839
  // Reset the unfilled bits.
1840
787k
  UnfilledBitsInLastUnit = 0;
1841
787k
  LastBitfieldStorageUnitSize = 0;
1842
1843
787k
  bool FieldPacked = Packed || 
D->hasAttr<PackedAttr>()759k
;
1844
1845
787k
  bool AlignIsRequired = false;
1846
787k
  CharUnits FieldSize;
1847
787k
  CharUnits FieldAlign;
1848
  // The amount of this class's dsize occupied by the field.
1849
  // This is equal to FieldSize unless we're permitted to pack
1850
  // into the field's tail padding.
1851
787k
  CharUnits EffectiveFieldSize;
1852
1853
782k
  auto setDeclInfo = [&](bool IsIncompleteArrayType) {
1854
782k
    auto TI = Context.getTypeInfoInChars(D->getType());
1855
782k
    FieldAlign = TI.Align;
1856
    // Flexible array members don't have any size, but they have to be
1857
    // aligned appropriately for their element type.
1858
782k
    EffectiveFieldSize = FieldSize =
1859
782k
        IsIncompleteArrayType ? 
CharUnits::Zero()140
: TI.Width;
1860
782k
    AlignIsRequired = TI.AlignIsRequired;
1861
782k
  };
1862
1863
787k
  if (D->getType()->isIncompleteArrayType()) {
1864
140
    setDeclInfo(true /* IsIncompleteArrayType */);
1865
787k
  } else if (const ReferenceType *RT = D->getType()->getAs<ReferenceType>()) {
1866
4.48k
    unsigned AS = Context.getTargetAddressSpace(RT->getPointeeType());
1867
4.48k
    EffectiveFieldSize = FieldSize = Context.toCharUnitsFromBits(
1868
4.48k
        Context.getTargetInfo().getPointerWidth(AS));
1869
4.48k
    FieldAlign = Context.toCharUnitsFromBits(
1870
4.48k
        Context.getTargetInfo().getPointerAlign(AS));
1871
782k
  } else {
1872
782k
    setDeclInfo(false /* IsIncompleteArrayType */);
1873
1874
    // A potentially-overlapping field occupies its dsize or nvsize, whichever
1875
    // is larger.
1876
782k
    if (PotentiallyOverlapping) {
1877
113
      const ASTRecordLayout &Layout = Context.getASTRecordLayout(FieldClass);
1878
113
      EffectiveFieldSize =
1879
113
          std::max(Layout.getNonVirtualSize(), Layout.getDataSize());
1880
113
    }
1881
1882
782k
    if (IsMsStruct) {
1883
      // If MS bitfield layout is required, figure out what type is being
1884
      // laid out and align the field to the width of that type.
1885
1886
      // Resolve all typedefs down to their base type and round up the field
1887
      // alignment if necessary.
1888
173
      QualType T = Context.getBaseElementType(D->getType());
1889
173
      if (const BuiltinType *BTy = T->getAs<BuiltinType>()) {
1890
166
        CharUnits TypeSize = Context.getTypeSizeInChars(BTy);
1891
1892
166
        if (!llvm::isPowerOf2_64(TypeSize.getQuantity())) {
1893
4
          assert(
1894
4
              !Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() &&
1895
4
              "Non PowerOf2 size in MSVC mode");
1896
          // Base types with sizes that aren't a power of two don't work
1897
          // with the layout rules for MS structs. This isn't an issue in
1898
          // MSVC itself since there are no such base data types there.
1899
          // On e.g. x86_32 mingw and linux, long double is 12 bytes though.
1900
          // Any structs involving that data type obviously can't be ABI
1901
          // compatible with MSVC regardless of how it is laid out.
1902
1903
          // Since ms_struct can be mass enabled (via a pragma or via the
1904
          // -mms-bitfields command line parameter), this can trigger for
1905
          // structs that don't actually need MSVC compatibility, so we
1906
          // need to be able to sidestep the ms_struct layout for these types.
1907
1908
          // Since the combination of -mms-bitfields together with structs
1909
          // like max_align_t (which contains a long double) for mingw is
1910
          // quite comon (and GCC handles it silently), just handle it
1911
          // silently there. For other targets that have ms_struct enabled
1912
          // (most probably via a pragma or attribute), trigger a diagnostic
1913
          // that defaults to an error.
1914
4
          if (!Context.getTargetInfo().getTriple().isWindowsGNUEnvironment())
1915
2
            Diag(D->getLocation(), diag::warn_npot_ms_struct);
1916
4
        }
1917
166
        if (TypeSize > FieldAlign &&
1918
13
            llvm::isPowerOf2_64(TypeSize.getQuantity()))
1919
9
          FieldAlign = TypeSize;
1920
166
      }
1921
173
    }
1922
782k
  }
1923
1924
  // The AIX `power` alignment rules apply the natural alignment of the
1925
  // "first member" if it is of a floating-point data type (or is an aggregate
1926
  // whose recursively "first" member or element is such a type). The alignment
1927
  // associated with these types for subsequent members use an alignment value
1928
  // where the floating-point data type is considered to have 4-byte alignment.
1929
  //
1930
  // For the purposes of the foregoing: vtable pointers, non-empty base classes,
1931
  // and zero-width bit-fields count as prior members; members of empty class
1932
  // types marked `no_unique_address` are not considered to be prior members.
1933
787k
  CharUnits PreferredAlign = FieldAlign;
1934
787k
  if (DefaultsToAIXPowerAlignment && 
!AlignIsRequired300
&&
1935
296
      (FoundFirstNonOverlappingEmptyFieldForAIX || 
IsNaturalAlign150
)) {
1936
164
    auto performBuiltinTypeAlignmentUpgrade = [&](const BuiltinType *BTy) {
1937
164
      if (BTy->getKind() == BuiltinType::Double ||
1938
102
          BTy->getKind() == BuiltinType::LongDouble) {
1939
64
        assert(PreferredAlign == CharUnits::fromQuantity(4) &&
1940
64
               "No need to upgrade the alignment value.");
1941
64
        PreferredAlign = CharUnits::fromQuantity(8);
1942
64
      }
1943
164
    };
1944
1945
190
    const Type *Ty = D->getType()->getBaseElementTypeUnsafe();
1946
190
    if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
1947
2
      performBuiltinTypeAlignmentUpgrade(CTy->getElementType()->castAs<BuiltinType>());
1948
188
    } else if (const BuiltinType *BTy = Ty->getAs<BuiltinType>()) {
1949
162
      performBuiltinTypeAlignmentUpgrade(BTy);
1950
26
    } else if (const RecordType *RT = Ty->getAs<RecordType>()) {
1951
24
      const RecordDecl *RD = RT->getDecl();
1952
24
      assert(RD && "Expected non-null RecordDecl.");
1953
24
      const ASTRecordLayout &FieldRecord = Context.getASTRecordLayout(RD);
1954
24
      PreferredAlign = FieldRecord.getPreferredAlignment();
1955
24
    }
1956
190
  }
1957
1958
  // The align if the field is not packed. This is to check if the attribute
1959
  // was unnecessary (-Wpacked).
1960
787k
  CharUnits UnpackedFieldAlign =
1961
786k
      !DefaultsToAIXPowerAlignment ? FieldAlign : 
PreferredAlign300
;
1962
787k
  CharUnits UnpackedFieldOffset = FieldOffset;
1963
1964
787k
  if (FieldPacked) {
1965
28.7k
    FieldAlign = CharUnits::One();
1966
28.7k
    PreferredAlign = CharUnits::One();
1967
28.7k
  }
1968
787k
  CharUnits MaxAlignmentInChars =
1969
787k
      Context.toCharUnitsFromBits(D->getMaxAlignment());
1970
787k
  FieldAlign = std::max(FieldAlign, MaxAlignmentInChars);
1971
787k
  PreferredAlign = std::max(PreferredAlign, MaxAlignmentInChars);
1972
787k
  UnpackedFieldAlign = std::max(UnpackedFieldAlign, MaxAlignmentInChars);
1973
1974
  // The maximum field alignment overrides the aligned attribute.
1975
787k
  if (!MaxFieldAlignment.isZero()) {
1976
212k
    FieldAlign = std::min(FieldAlign, MaxFieldAlignment);
1977
212k
    PreferredAlign = std::min(PreferredAlign, MaxFieldAlignment);
1978
212k
    UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignment);
1979
212k
  }
1980
1981
787k
  CharUnits AlignTo =
1982
786k
      !DefaultsToAIXPowerAlignment ? FieldAlign : 
PreferredAlign300
;
1983
  // Round up the current record size to the field's alignment boundary.
1984
787k
  FieldOffset = FieldOffset.alignTo(AlignTo);
1985
787k
  UnpackedFieldOffset = UnpackedFieldOffset.alignTo(UnpackedFieldAlign);
1986
1987
787k
  if (UseExternalLayout) {
1988
17.0k
    FieldOffset = Context.toCharUnitsFromBits(
1989
17.0k
        updateExternalFieldOffset(D, Context.toBits(FieldOffset)));
1990
1991
17.0k
    if (!IsUnion && 
EmptySubobjects14.3k
) {
1992
      // Record the fact that we're placing a field at this offset.
1993
14.2k
      bool Allowed = EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset);
1994
14.2k
      (void)Allowed;
1995
14.2k
      assert(Allowed && "Externally-placed field cannot be placed here");
1996
14.2k
    }
1997
770k
  } else {
1998
770k
    if (!IsUnion && 
EmptySubobjects725k
) {
1999
      // Check if we can place the field at this offset.
2000
271k
      while (!EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset)) {
2001
        // We couldn't place the field at the offset. Try again at a new offset.
2002
        // We try offset 0 (for an empty field) and then dsize(C) onwards.
2003
49
        if (FieldOffset == CharUnits::Zero() &&
2004
42
            getDataSize() != CharUnits::Zero())
2005
8
          FieldOffset = getDataSize().alignTo(AlignTo);
2006
41
        else
2007
41
          FieldOffset += AlignTo;
2008
49
      }
2009
271k
    }
2010
770k
  }
2011
2012
  // Place this field at the current location.
2013
787k
  FieldOffsets.push_back(Context.toBits(FieldOffset));
2014
2015
787k
  if (!UseExternalLayout)
2016
770k
    CheckFieldPadding(Context.toBits(FieldOffset), UnpaddedFieldOffset,
2017
770k
                      Context.toBits(UnpackedFieldOffset),
2018
770k
                      Context.toBits(UnpackedFieldAlign), FieldPacked, D);
2019
2020
787k
  if (InsertExtraPadding) {
2021
36
    CharUnits ASanAlignment = CharUnits::fromQuantity(8);
2022
36
    CharUnits ExtraSizeForAsan = ASanAlignment;
2023
36
    if (FieldSize % ASanAlignment)
2024
30
      ExtraSizeForAsan +=
2025
30
          ASanAlignment - CharUnits::fromQuantity(FieldSize % ASanAlignment);
2026
36
    EffectiveFieldSize = FieldSize = FieldSize + ExtraSizeForAsan;
2027
36
  }
2028
2029
  // Reserve space for this field.
2030
787k
  if (!IsOverlappingEmptyField) {
2031
787k
    uint64_t EffectiveFieldSizeInBits = Context.toBits(EffectiveFieldSize);
2032
787k
    if (IsUnion)
2033
46.8k
      setDataSize(std::max(getDataSizeInBits(), EffectiveFieldSizeInBits));
2034
740k
    else
2035
740k
      setDataSize(FieldOffset + EffectiveFieldSize);
2036
2037
787k
    PaddedFieldSize = std::max(PaddedFieldSize, FieldOffset + FieldSize);
2038
787k
    setSize(std::max(getSizeInBits(), getDataSizeInBits()));
2039
93
  } else {
2040
93
    setSize(std::max(getSizeInBits(),
2041
93
                     (uint64_t)Context.toBits(FieldOffset + FieldSize)));
2042
93
  }
2043
2044
  // Remember max struct/class ABI-specified alignment.
2045
787k
  UnadjustedAlignment = std::max(UnadjustedAlignment, FieldAlign);
2046
787k
  UpdateAlignment(FieldAlign, UnpackedFieldAlign, PreferredAlign);
2047
787k
}
2048
2049
312k
void ItaniumRecordLayoutBuilder::FinishLayout(const NamedDecl *D) {
2050
  // In C++, records cannot be of size 0.
2051
312k
  if (Context.getLangOpts().CPlusPlus && 
getSizeInBits() == 0212k
) {
2052
48.6k
    if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
2053
      // Compatibility with gcc requires a class (pod or non-pod)
2054
      // which is not empty but of size 0; such as having fields of
2055
      // array of zero-length, remains of Size 0
2056
48.6k
      if (RD->isEmpty())
2057
47.5k
        setSize(CharUnits::One());
2058
48.6k
    }
2059
61
    else
2060
61
      setSize(CharUnits::One());
2061
48.6k
  }
2062
2063
  // If we have any remaining field tail padding, include that in the overall
2064
  // size.
2065
312k
  setSize(std::max(getSizeInBits(), (uint64_t)Context.toBits(PaddedFieldSize)));
2066
2067
  // Finally, round the size of the record up to the alignment of the
2068
  // record itself.
2069
312k
  uint64_t UnpaddedSize = getSizeInBits() - UnfilledBitsInLastUnit;
2070
312k
  uint64_t UnpackedSizeInBits =
2071
312k
      llvm::alignTo(getSizeInBits(), Context.toBits(UnpackedAlignment));
2072
2073
312k
  uint64_t RoundedSize = llvm::alignTo(
2074
312k
      getSizeInBits(),
2075
312k
      Context.toBits(!Context.getTargetInfo().defaultsToAIXPowerAlignment()
2076
312k
                         ? Alignment
2077
254
                         : PreferredAlignment));
2078
2079
312k
  if (UseExternalLayout) {
2080
    // If we're inferring alignment, and the external size is smaller than
2081
    // our size after we've rounded up to alignment, conservatively set the
2082
    // alignment to 1.
2083
12.8k
    if (InferAlignment && 
External.Size < RoundedSize4.42k
) {
2084
13
      Alignment = CharUnits::One();
2085
13
      PreferredAlignment = CharUnits::One();
2086
13
      InferAlignment = false;
2087
13
    }
2088
12.8k
    setSize(External.Size);
2089
12.8k
    return;
2090
12.8k
  }
2091
2092
  // Set the size to the final size.
2093
300k
  setSize(RoundedSize);
2094
2095
300k
  unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
2096
300k
  if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
2097
    // Warn if padding was introduced to the struct/class/union.
2098
294k
    if (getSizeInBits() > UnpaddedSize) {
2099
13.0k
      unsigned PadSize = getSizeInBits() - UnpaddedSize;
2100
13.0k
      bool InBits = true;
2101
13.0k
      if (PadSize % CharBitNum == 0) {
2102
12.3k
        PadSize = PadSize / CharBitNum;
2103
12.3k
        InBits = false;
2104
12.3k
      }
2105
13.0k
      Diag(RD->getLocation(), diag::warn_padded_struct_size)
2106
13.0k
          << Context.getTypeDeclType(RD)
2107
13.0k
          << PadSize
2108
12.3k
          << (InBits ? 
1644
: 0); // (byte|bit)
2109
13.0k
    }
2110
2111
    // Warn if we packed it unnecessarily, when the unpacked alignment is not
2112
    // greater than the one after packing, the size in bits doesn't change and
2113
    // the offset of each field is identical.
2114
294k
    if (Packed && 
UnpackedAlignment <= Alignment7.57k
&&
2115
1.13k
        UnpackedSizeInBits == getSizeInBits() && !HasPackedField)
2116
1.12k
      Diag(D->getLocation(), diag::warn_unnecessary_packed)
2117
1.12k
          << Context.getTypeDeclType(RD);
2118
294k
  }
2119
300k
}
2120
2121
void ItaniumRecordLayoutBuilder::UpdateAlignment(
2122
    CharUnits NewAlignment, CharUnits UnpackedNewAlignment,
2123
861k
    CharUnits PreferredNewAlignment) {
2124
  // The alignment is not modified when using 'mac68k' alignment or when
2125
  // we have an externally-supplied layout that also provides overall alignment.
2126
861k
  if (IsMac68kAlign || 
(861k
UseExternalLayout861k
&&
!InferAlignment23.0k
))
2127
15.0k
    return;
2128
2129
846k
  if (NewAlignment > Alignment) {
2130
242k
    assert(llvm::isPowerOf2_64(NewAlignment.getQuantity()) &&
2131
242k
           "Alignment not a power of 2");
2132
242k
    Alignment = NewAlignment;
2133
242k
  }
2134
2135
846k
  if (UnpackedNewAlignment > UnpackedAlignment) {
2136
250k
    assert(llvm::isPowerOf2_64(UnpackedNewAlignment.getQuantity()) &&
2137
250k
           "Alignment not a power of 2");
2138
250k
    UnpackedAlignment = UnpackedNewAlignment;
2139
250k
  }
2140
2141
846k
  if (PreferredNewAlignment > PreferredAlignment) {
2142
242k
    assert(llvm::isPowerOf2_64(PreferredNewAlignment.getQuantity()) &&
2143
242k
           "Alignment not a power of 2");
2144
242k
    PreferredAlignment = PreferredNewAlignment;
2145
242k
  }
2146
846k
}
2147
2148
uint64_t
2149
ItaniumRecordLayoutBuilder::updateExternalFieldOffset(const FieldDecl *Field,
2150
18.7k
                                                      uint64_t ComputedOffset) {
2151
18.7k
  uint64_t ExternalFieldOffset = External.getExternalFieldOffset(Field);
2152
2153
18.7k
  if (InferAlignment && 
ExternalFieldOffset < ComputedOffset6.03k
) {
2154
    // The externally-supplied field offset is before the field offset we
2155
    // computed. Assume that the structure is packed.
2156
9
    Alignment = CharUnits::One();
2157
9
    PreferredAlignment = CharUnits::One();
2158
9
    InferAlignment = false;
2159
9
  }
2160
2161
  // Use the externally-supplied field offset.
2162
18.7k
  return ExternalFieldOffset;
2163
18.7k
}
2164
2165
/// Get diagnostic %select index for tag kind for
2166
/// field padding diagnostic message.
2167
/// WARNING: Indexes apply to particular diagnostics only!
2168
///
2169
/// \returns diagnostic %select index.
2170
15.7k
static unsigned getPaddingDiagFromTagKind(TagTypeKind Tag) {
2171
15.7k
  switch (Tag) {
2172
15.1k
  case TTK_Struct: return 0;
2173
0
  case TTK_Interface: return 1;
2174
626
  case TTK_Class: return 2;
2175
0
  default: llvm_unreachable("Invalid tag kind for field padding diagnostic!");
2176
15.7k
  }
2177
15.7k
}
2178
2179
void ItaniumRecordLayoutBuilder::CheckFieldPadding(
2180
    uint64_t Offset, uint64_t UnpaddedOffset, uint64_t UnpackedOffset,
2181
787k
    unsigned UnpackedAlign, bool isPacked, const FieldDecl *D) {
2182
  // We let objc ivars without warning, objc interfaces generally are not used
2183
  // for padding tricks.
2184
787k
  if (isa<ObjCIvarDecl>(D))
2185
7.22k
    return;
2186
2187
  // Don't warn about structs created without a SourceLocation.  This can
2188
  // be done by clients of the AST, such as codegen.
2189
780k
  if (D->getLocation().isInvalid())
2190
82.0k
    return;
2191
2192
698k
  unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
2193
2194
  // Warn if padding was introduced to the struct/class.
2195
698k
  if (!IsUnion && 
Offset > UnpaddedOffset654k
) {
2196
15.7k
    unsigned PadSize = Offset - UnpaddedOffset;
2197
15.7k
    bool InBits = true;
2198
15.7k
    if (PadSize % CharBitNum == 0) {
2199
15.2k
      PadSize = PadSize / CharBitNum;
2200
15.2k
      InBits = false;
2201
15.2k
    }
2202
15.7k
    if (D->getIdentifier())
2203
15.5k
      Diag(D->getLocation(), diag::warn_padded_struct_field)
2204
15.5k
          << getPaddingDiagFromTagKind(D->getParent()->getTagKind())
2205
15.5k
          << Context.getTypeDeclType(D->getParent())
2206
15.5k
          << PadSize
2207
15.1k
          << (InBits ? 
1394
: 0) // (byte|bit)
2208
15.5k
          << D->getIdentifier();
2209
268
    else
2210
268
      Diag(D->getLocation(), diag::warn_padded_struct_anon_field)
2211
268
          << getPaddingDiagFromTagKind(D->getParent()->getTagKind())
2212
268
          << Context.getTypeDeclType(D->getParent())
2213
268
          << PadSize
2214
179
          << (InBits ? 
189
: 0); // (byte|bit)
2215
15.7k
 }
2216
698k
 if (isPacked && 
Offset != UnpackedOffset18.0k
) {
2217
2.36k
   HasPackedField = true;
2218
2.36k
 }
2219
698k
}
2220
2221
static const CXXMethodDecl *computeKeyFunction(ASTContext &Context,
2222
128k
                                               const CXXRecordDecl *RD) {
2223
  // If a class isn't polymorphic it doesn't have a key function.
2224
128k
  if (!RD->isPolymorphic())
2225
106k
    return nullptr;
2226
2227
  // A class that is not externally visible doesn't have a key function. (Or
2228
  // at least, there's no point to assigning a key function to such a class;
2229
  // this doesn't affect the ABI.)
2230
22.2k
  if (!RD->isExternallyVisible())
2231
847
    return nullptr;
2232
2233
  // Template instantiations don't have key functions per Itanium C++ ABI 5.2.6.
2234
  // Same behavior as GCC.
2235
21.4k
  TemplateSpecializationKind TSK = RD->getTemplateSpecializationKind();
2236
21.4k
  if (TSK == TSK_ImplicitInstantiation ||
2237
19.0k
      TSK == TSK_ExplicitInstantiationDeclaration ||
2238
17.4k
      TSK == TSK_ExplicitInstantiationDefinition)
2239
4.17k
    return nullptr;
2240
2241
17.2k
  bool allowInlineFunctions =
2242
17.2k
    Context.getTargetInfo().getCXXABI().canKeyFunctionBeInline();
2243
2244
76.4k
  for (const CXXMethodDecl *MD : RD->methods()) {
2245
76.4k
    if (!MD->isVirtual())
2246
57.0k
      continue;
2247
2248
19.4k
    if (MD->isPure())
2249
680
      continue;
2250
2251
    // Ignore implicit member functions, they are always marked as inline, but
2252
    // they don't have a body until they're defined.
2253
18.7k
    if (MD->isImplicit())
2254
1.34k
      continue;
2255
2256
17.3k
    if (MD->isInlineSpecified() || 
MD->isConstexpr()17.3k
)
2257
132
      continue;
2258
2259
17.2k
    if (MD->hasInlineBody())
2260
5.14k
      continue;
2261
2262
    // Ignore inline deleted or defaulted functions.
2263
12.1k
    if (!MD->isUserProvided())
2264
59
      continue;
2265
2266
    // In certain ABIs, ignore functions with out-of-line inline definitions.
2267
12.0k
    if (!allowInlineFunctions) {
2268
222
      const FunctionDecl *Def;
2269
222
      if (MD->hasBody(Def) && 
Def->isInlineSpecified()158
)
2270
88
        continue;
2271
11.9k
    }
2272
2273
11.9k
    if (Context.getLangOpts().CUDA) {
2274
      // While compiler may see key method in this TU, during CUDA
2275
      // compilation we should ignore methods that are not accessible
2276
      // on this side of compilation.
2277
7
      if (Context.getLangOpts().CUDAIsDevice) {
2278
        // In device mode ignore methods without __device__ attribute.
2279
4
        if (!MD->hasAttr<CUDADeviceAttr>())
2280
2
          continue;
2281
3
      } else {
2282
        // In host mode ignore __device__-only methods.
2283
3
        if (!MD->hasAttr<CUDAHostAttr>() && MD->hasAttr<CUDADeviceAttr>())
2284
1
          continue;
2285
11.9k
      }
2286
7
    }
2287
2288
    // If the key function is dllimport but the class isn't, then the class has
2289
    // no key function. The DLL that exports the key function won't export the
2290
    // vtable in this case.
2291
11.9k
    if (MD->hasAttr<DLLImportAttr>() && 
!RD->hasAttr<DLLImportAttr>()89
)
2292
82
      return nullptr;
2293
2294
    // We found it.
2295
11.8k
    return MD;
2296
11.8k
  }
2297
2298
5.27k
  return nullptr;
2299
17.2k
}
2300
2301
DiagnosticBuilder ItaniumRecordLayoutBuilder::Diag(SourceLocation Loc,
2302
29.9k
                                                   unsigned DiagID) {
2303
29.9k
  return Context.getDiagnostics().Report(Loc, DiagID);
2304
29.9k
}
2305
2306
/// Does the target C++ ABI require us to skip over the tail-padding
2307
/// of the given class (considering it as a base class) when allocating
2308
/// objects?
2309
186k
static bool mustSkipTailPadding(TargetCXXABI ABI, const CXXRecordDecl *RD) {
2310
186k
  switch (ABI.getTailPaddingUseRules()) {
2311
0
  case TargetCXXABI::AlwaysUseTailPadding:
2312
0
    return false;
2313
2314
186k
  case TargetCXXABI::UseTailPaddingUnlessPOD03:
2315
    // FIXME: To the extent that this is meant to cover the Itanium ABI
2316
    // rules, we should implement the restrictions about over-sized
2317
    // bitfields:
2318
    //
2319
    // http://itanium-cxx-abi.github.io/cxx-abi/abi.html#POD :
2320
    //   In general, a type is considered a POD for the purposes of
2321
    //   layout if it is a POD type (in the sense of ISO C++
2322
    //   [basic.types]). However, a POD-struct or POD-union (in the
2323
    //   sense of ISO C++ [class]) with a bitfield member whose
2324
    //   declared width is wider than the declared type of the
2325
    //   bitfield is not a POD for the purpose of layout.  Similarly,
2326
    //   an array type is not a POD for the purpose of layout if the
2327
    //   element type of the array is not a POD for the purpose of
2328
    //   layout.
2329
    //
2330
    //   Where references to the ISO C++ are made in this paragraph,
2331
    //   the Technical Corrigendum 1 version of the standard is
2332
    //   intended.
2333
186k
    return RD->isPOD();
2334
2335
260
  case TargetCXXABI::UseTailPaddingUnlessPOD11:
2336
    // This is equivalent to RD->getTypeForDecl().isCXX11PODType(),
2337
    // but with a lot of abstraction penalty stripped off.  This does
2338
    // assume that these properties are set correctly even in C++98
2339
    // mode; fortunately, that is true because we want to assign
2340
    // consistently semantics to the type-traits intrinsics (or at
2341
    // least as many of them as possible).
2342
260
    return RD->isTrivial() && 
RD->isCXX11StandardLayout()60
;
2343
0
  }
2344
2345
0
  llvm_unreachable("bad tail-padding use kind");
2346
0
}
2347
2348
314k
static bool isMsLayout(const ASTContext &Context) {
2349
314k
  return Context.getTargetInfo().getCXXABI().isMicrosoft();
2350
314k
}
2351
2352
// This section contains an implementation of struct layout that is, up to the
2353
// included tests, compatible with cl.exe (2013).  The layout produced is
2354
// significantly different than those produced by the Itanium ABI.  Here we note
2355
// the most important differences.
2356
//
2357
// * The alignment of bitfields in unions is ignored when computing the
2358
//   alignment of the union.
2359
// * The existence of zero-width bitfield that occurs after anything other than
2360
//   a non-zero length bitfield is ignored.
2361
// * There is no explicit primary base for the purposes of layout.  All bases
2362
//   with vfptrs are laid out first, followed by all bases without vfptrs.
2363
// * The Itanium equivalent vtable pointers are split into a vfptr (virtual
2364
//   function pointer) and a vbptr (virtual base pointer).  They can each be
2365
//   shared with a, non-virtual bases. These bases need not be the same.  vfptrs
2366
//   always occur at offset 0.  vbptrs can occur at an arbitrary offset and are
2367
//   placed after the lexicographically last non-virtual base.  This placement
2368
//   is always before fields but can be in the middle of the non-virtual bases
2369
//   due to the two-pass layout scheme for non-virtual-bases.
2370
// * Virtual bases sometimes require a 'vtordisp' field that is laid out before
2371
//   the virtual base and is used in conjunction with virtual overrides during
2372
//   construction and destruction.  This is always a 4 byte value and is used as
2373
//   an alternative to constructor vtables.
2374
// * vtordisps are allocated in a block of memory with size and alignment equal
2375
//   to the alignment of the completed structure (before applying __declspec(
2376
//   align())).  The vtordisp always occur at the end of the allocation block,
2377
//   immediately prior to the virtual base.
2378
// * vfptrs are injected after all bases and fields have been laid out.  In
2379
//   order to guarantee proper alignment of all fields, the vfptr injection
2380
//   pushes all bases and fields back by the alignment imposed by those bases
2381
//   and fields.  This can potentially add a significant amount of padding.
2382
//   vfptrs are always injected at offset 0.
2383
// * vbptrs are injected after all bases and fields have been laid out.  In
2384
//   order to guarantee proper alignment of all fields, the vfptr injection
2385
//   pushes all bases and fields back by the alignment imposed by those bases
2386
//   and fields.  This can potentially add a significant amount of padding.
2387
//   vbptrs are injected immediately after the last non-virtual base as
2388
//   lexicographically ordered in the code.  If this site isn't pointer aligned
2389
//   the vbptr is placed at the next properly aligned location.  Enough padding
2390
//   is added to guarantee a fit.
2391
// * The last zero sized non-virtual base can be placed at the end of the
2392
//   struct (potentially aliasing another object), or may alias with the first
2393
//   field, even if they are of the same type.
2394
// * The last zero size virtual base may be placed at the end of the struct
2395
//   potentially aliasing another object.
2396
// * The ABI attempts to avoid aliasing of zero sized bases by adding padding
2397
//   between bases or vbases with specific properties.  The criteria for
2398
//   additional padding between two bases is that the first base is zero sized
2399
//   or ends with a zero sized subobject and the second base is zero sized or
2400
//   trails with a zero sized base or field (sharing of vfptrs can reorder the
2401
//   layout of the so the leading base is not always the first one declared).
2402
//   This rule does take into account fields that are not records, so padding
2403
//   will occur even if the last field is, e.g. an int. The padding added for
2404
//   bases is 1 byte.  The padding added between vbases depends on the alignment
2405
//   of the object but is at least 4 bytes (in both 32 and 64 bit modes).
2406
// * There is no concept of non-virtual alignment, non-virtual alignment and
2407
//   alignment are always identical.
2408
// * There is a distinction between alignment and required alignment.
2409
//   __declspec(align) changes the required alignment of a struct.  This
2410
//   alignment is _always_ obeyed, even in the presence of #pragma pack. A
2411
//   record inherits required alignment from all of its fields and bases.
2412
// * __declspec(align) on bitfields has the effect of changing the bitfield's
2413
//   alignment instead of its required alignment.  This is the only known way
2414
//   to make the alignment of a struct bigger than 8.  Interestingly enough
2415
//   this alignment is also immune to the effects of #pragma pack and can be
2416
//   used to create structures with large alignment under #pragma pack.
2417
//   However, because it does not impact required alignment, such a structure,
2418
//   when used as a field or base, will not be aligned if #pragma pack is
2419
//   still active at the time of use.
2420
//
2421
// Known incompatibilities:
2422
// * all: #pragma pack between fields in a record
2423
// * 2010 and back: If the last field in a record is a bitfield, every object
2424
//   laid out after the record will have extra padding inserted before it.  The
2425
//   extra padding will have size equal to the size of the storage class of the
2426
//   bitfield.  0 sized bitfields don't exhibit this behavior and the extra
2427
//   padding can be avoided by adding a 0 sized bitfield after the non-zero-
2428
//   sized bitfield.
2429
// * 2012 and back: In 64-bit mode, if the alignment of a record is 16 or
2430
//   greater due to __declspec(align()) then a second layout phase occurs after
2431
//   The locations of the vf and vb pointers are known.  This layout phase
2432
//   suffers from the "last field is a bitfield" bug in 2010 and results in
2433
//   _every_ field getting padding put in front of it, potentially including the
2434
//   vfptr, leaving the vfprt at a non-zero location which results in a fault if
2435
//   anything tries to read the vftbl.  The second layout phase also treats
2436
//   bitfields as separate entities and gives them each storage rather than
2437
//   packing them.  Additionally, because this phase appears to perform a
2438
//   (an unstable) sort on the members before laying them out and because merged
2439
//   bitfields have the same address, the bitfields end up in whatever order
2440
//   the sort left them in, a behavior we could never hope to replicate.
2441
2442
namespace {
2443
struct MicrosoftRecordLayoutBuilder {
2444
  struct ElementInfo {
2445
    CharUnits Size;
2446
    CharUnits Alignment;
2447
  };
2448
  typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
2449
5.10k
  MicrosoftRecordLayoutBuilder(const ASTContext &Context) : Context(Context) {}
2450
private:
2451
  MicrosoftRecordLayoutBuilder(const MicrosoftRecordLayoutBuilder &) = delete;
2452
  void operator=(const MicrosoftRecordLayoutBuilder &) = delete;
2453
public:
2454
  void layout(const RecordDecl *RD);
2455
  void cxxLayout(const CXXRecordDecl *RD);
2456
  /// Initializes size and alignment and honors some flags.
2457
  void initializeLayout(const RecordDecl *RD);
2458
  /// Initialized C++ layout, compute alignment and virtual alignment and
2459
  /// existence of vfptrs and vbptrs.  Alignment is needed before the vfptr is
2460
  /// laid out.
2461
  void initializeCXXLayout(const CXXRecordDecl *RD);
2462
  void layoutNonVirtualBases(const CXXRecordDecl *RD);
2463
  void layoutNonVirtualBase(const CXXRecordDecl *RD,
2464
                            const CXXRecordDecl *BaseDecl,
2465
                            const ASTRecordLayout &BaseLayout,
2466
                            const ASTRecordLayout *&PreviousBaseLayout);
2467
  void injectVFPtr(const CXXRecordDecl *RD);
2468
  void injectVBPtr(const CXXRecordDecl *RD);
2469
  /// Lays out the fields of the record.  Also rounds size up to
2470
  /// alignment.
2471
  void layoutFields(const RecordDecl *RD);
2472
  void layoutField(const FieldDecl *FD);
2473
  void layoutBitField(const FieldDecl *FD);
2474
  /// Lays out a single zero-width bit-field in the record and handles
2475
  /// special cases associated with zero-width bit-fields.
2476
  void layoutZeroWidthBitField(const FieldDecl *FD);
2477
  void layoutVirtualBases(const CXXRecordDecl *RD);
2478
  void finalizeLayout(const RecordDecl *RD);
2479
  /// Gets the size and alignment of a base taking pragma pack and
2480
  /// __declspec(align) into account.
2481
  ElementInfo getAdjustedElementInfo(const ASTRecordLayout &Layout);
2482
  /// Gets the size and alignment of a field taking pragma  pack and
2483
  /// __declspec(align) into account.  It also updates RequiredAlignment as a
2484
  /// side effect because it is most convenient to do so here.
2485
  ElementInfo getAdjustedElementInfo(const FieldDecl *FD);
2486
  /// Places a field at an offset in CharUnits.
2487
2.82k
  void placeFieldAtOffset(CharUnits FieldOffset) {
2488
2.82k
    FieldOffsets.push_back(Context.toBits(FieldOffset));
2489
2.82k
  }
2490
  /// Places a bitfield at a bit offset.
2491
50
  void placeFieldAtBitOffset(uint64_t FieldOffset) {
2492
50
    FieldOffsets.push_back(FieldOffset);
2493
50
  }
2494
  /// Compute the set of virtual bases for which vtordisps are required.
2495
  void computeVtorDispSet(
2496
      llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtorDispSet,
2497
      const CXXRecordDecl *RD) const;
2498
  const ASTContext &Context;
2499
  /// The size of the record being laid out.
2500
  CharUnits Size;
2501
  /// The non-virtual size of the record layout.
2502
  CharUnits NonVirtualSize;
2503
  /// The data size of the record layout.
2504
  CharUnits DataSize;
2505
  /// The current alignment of the record layout.
2506
  CharUnits Alignment;
2507
  /// The maximum allowed field alignment. This is set by #pragma pack.
2508
  CharUnits MaxFieldAlignment;
2509
  /// The alignment that this record must obey.  This is imposed by
2510
  /// __declspec(align()) on the record itself or one of its fields or bases.
2511
  CharUnits RequiredAlignment;
2512
  /// The size of the allocation of the currently active bitfield.
2513
  /// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield
2514
  /// is true.
2515
  CharUnits CurrentBitfieldSize;
2516
  /// Offset to the virtual base table pointer (if one exists).
2517
  CharUnits VBPtrOffset;
2518
  /// Minimum record size possible.
2519
  CharUnits MinEmptyStructSize;
2520
  /// The size and alignment info of a pointer.
2521
  ElementInfo PointerInfo;
2522
  /// The primary base class (if one exists).
2523
  const CXXRecordDecl *PrimaryBase;
2524
  /// The class we share our vb-pointer with.
2525
  const CXXRecordDecl *SharedVBPtrBase;
2526
  /// The collection of field offsets.
2527
  SmallVector<uint64_t, 16> FieldOffsets;
2528
  /// Base classes and their offsets in the record.
2529
  BaseOffsetsMapTy Bases;
2530
  /// virtual base classes and their offsets in the record.
2531
  ASTRecordLayout::VBaseOffsetsMapTy VBases;
2532
  /// The number of remaining bits in our last bitfield allocation.
2533
  /// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield is
2534
  /// true.
2535
  unsigned RemainingBitsInField;
2536
  bool IsUnion : 1;
2537
  /// True if the last field laid out was a bitfield and was not 0
2538
  /// width.
2539
  bool LastFieldIsNonZeroWidthBitfield : 1;
2540
  /// True if the class has its own vftable pointer.
2541
  bool HasOwnVFPtr : 1;
2542
  /// True if the class has a vbtable pointer.
2543
  bool HasVBPtr : 1;
2544
  /// True if the last sub-object within the type is zero sized or the
2545
  /// object itself is zero sized.  This *does not* count members that are not
2546
  /// records.  Only used for MS-ABI.
2547
  bool EndsWithZeroSizedObject : 1;
2548
  /// True if this class is zero sized or first base is zero sized or
2549
  /// has this property.  Only used for MS-ABI.
2550
  bool LeadsWithZeroSizedBase : 1;
2551
2552
  /// True if the external AST source provided a layout for this record.
2553
  bool UseExternalLayout : 1;
2554
2555
  /// The layout provided by the external AST source. Only active if
2556
  /// UseExternalLayout is true.
2557
  ExternalLayout External;
2558
};
2559
} // namespace
2560
2561
MicrosoftRecordLayoutBuilder::ElementInfo
2562
MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
2563
2.85k
    const ASTRecordLayout &Layout) {
2564
2.85k
  ElementInfo Info;
2565
2.85k
  Info.Alignment = Layout.getAlignment();
2566
  // Respect pragma pack.
2567
2.85k
  if (!MaxFieldAlignment.isZero())
2568
34
    Info.Alignment = std::min(Info.Alignment, MaxFieldAlignment);
2569
  // Track zero-sized subobjects here where it's already available.
2570
2.85k
  EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
2571
  // Respect required alignment, this is necessary because we may have adjusted
2572
  // the alignment in the case of pragam pack.  Note that the required alignment
2573
  // doesn't actually apply to the struct alignment at this point.
2574
2.85k
  Alignment = std::max(Alignment, Info.Alignment);
2575
2.85k
  RequiredAlignment = std::max(RequiredAlignment, Layout.getRequiredAlignment());
2576
2.85k
  Info.Alignment = std::max(Info.Alignment, Layout.getRequiredAlignment());
2577
2.85k
  Info.Size = Layout.getNonVirtualSize();
2578
2.85k
  return Info;
2579
2.85k
}
2580
2581
MicrosoftRecordLayoutBuilder::ElementInfo
2582
MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
2583
2.85k
    const FieldDecl *FD) {
2584
  // Get the alignment of the field type's natural alignment, ignore any
2585
  // alignment attributes.
2586
2.85k
  auto TInfo =
2587
2.85k
      Context.getTypeInfoInChars(FD->getType()->getUnqualifiedDesugaredType());
2588
2.85k
  ElementInfo Info{TInfo.Width, TInfo.Align};
2589
  // Respect align attributes on the field.
2590
2.85k
  CharUnits FieldRequiredAlignment =
2591
2.85k
      Context.toCharUnitsFromBits(FD->getMaxAlignment());
2592
  // Respect align attributes on the type.
2593
2.85k
  if (Context.isAlignmentRequired(FD->getType()))
2594
81
    FieldRequiredAlignment = std::max(
2595
81
        Context.getTypeAlignInChars(FD->getType()), FieldRequiredAlignment);
2596
  // Respect attributes applied to subobjects of the field.
2597
2.85k
  if (FD->isBitField())
2598
    // For some reason __declspec align impacts alignment rather than required
2599
    // alignment when it is applied to bitfields.
2600
200
    Info.Alignment = std::max(Info.Alignment, FieldRequiredAlignment);
2601
2.65k
  else {
2602
2.65k
    if (auto RT =
2603
215
            FD->getType()->getBaseElementTypeUnsafe()->getAs<RecordType>()) {
2604
215
      auto const &Layout = Context.getASTRecordLayout(RT->getDecl());
2605
215
      EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
2606
215
      FieldRequiredAlignment = std::max(FieldRequiredAlignment,
2607
215
                                        Layout.getRequiredAlignment());
2608
215
    }
2609
    // Capture required alignment as a side-effect.
2610
2.65k
    RequiredAlignment = std::max(RequiredAlignment, FieldRequiredAlignment);
2611
2.65k
  }
2612
  // Respect pragma pack, attribute pack and declspec align
2613
2.85k
  if (!MaxFieldAlignment.isZero())
2614
257
    Info.Alignment = std::min(Info.Alignment, MaxFieldAlignment);
2615
2.85k
  if (FD->hasAttr<PackedAttr>())
2616
7
    Info.Alignment = CharUnits::One();
2617
2.85k
  Info.Alignment = std::max(Info.Alignment, FieldRequiredAlignment);
2618
2.85k
  return Info;
2619
2.85k
}
2620
2621
331
void MicrosoftRecordLayoutBuilder::layout(const RecordDecl *RD) {
2622
  // For C record layout, zero-sized records always have size 4.
2623
331
  MinEmptyStructSize = CharUnits::fromQuantity(4);
2624
331
  initializeLayout(RD);
2625
331
  layoutFields(RD);
2626
331
  DataSize = Size = Size.alignTo(Alignment);
2627
331
  RequiredAlignment = std::max(
2628
331
      RequiredAlignment, Context.toCharUnitsFromBits(RD->getMaxAlignment()));
2629
331
  finalizeLayout(RD);
2630
331
}
2631
2632
4.77k
void MicrosoftRecordLayoutBuilder::cxxLayout(const CXXRecordDecl *RD) {
2633
  // The C++ standard says that empty structs have size 1.
2634
4.77k
  MinEmptyStructSize = CharUnits::One();
2635
4.77k
  initializeLayout(RD);
2636
4.77k
  initializeCXXLayout(RD);
2637
4.77k
  layoutNonVirtualBases(RD);
2638
4.77k
  layoutFields(RD);
2639
4.77k
  injectVBPtr(RD);
2640
4.77k
  injectVFPtr(RD);
2641
4.77k
  if (HasOwnVFPtr || 
(3.97k
HasVBPtr3.97k
&&
!SharedVBPtrBase740
))
2642
1.33k
    Alignment = std::max(Alignment, PointerInfo.Alignment);
2643
4.77k
  auto RoundingAlignment = Alignment;
2644
4.77k
  if (!MaxFieldAlignment.isZero())
2645
56
    RoundingAlignment = std::min(RoundingAlignment, MaxFieldAlignment);
2646
4.77k
  if (!UseExternalLayout)
2647
4.76k
    Size = Size.alignTo(RoundingAlignment);
2648
4.77k
  NonVirtualSize = Size;
2649
4.77k
  RequiredAlignment = std::max(
2650
4.77k
      RequiredAlignment, Context.toCharUnitsFromBits(RD->getMaxAlignment()));
2651
4.77k
  layoutVirtualBases(RD);
2652
4.77k
  finalizeLayout(RD);
2653
4.77k
}
2654
2655
5.10k
void MicrosoftRecordLayoutBuilder::initializeLayout(const RecordDecl *RD) {
2656
5.10k
  IsUnion = RD->isUnion();
2657
5.10k
  Size = CharUnits::Zero();
2658
5.10k
  Alignment = CharUnits::One();
2659
  // In 64-bit mode we always perform an alignment step after laying out vbases.
2660
  // In 32-bit mode we do not.  The check to see if we need to perform alignment
2661
  // checks the RequiredAlignment field and performs alignment if it isn't 0.
2662
5.10k
  RequiredAlignment = Context.getTargetInfo().getTriple().isArch64Bit()
2663
2.39k
                          ? CharUnits::One()
2664
2.71k
                          : CharUnits::Zero();
2665
  // Compute the maximum field alignment.
2666
5.10k
  MaxFieldAlignment = CharUnits::Zero();
2667
  // Honor the default struct packing maximum alignment flag.
2668
5.10k
  if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct)
2669
0
      MaxFieldAlignment = CharUnits::fromQuantity(DefaultMaxFieldAlignment);
2670
  // Honor the packing attribute.  The MS-ABI ignores pragma pack if its larger
2671
  // than the pointer size.
2672
5.10k
  if (const MaxFieldAlignmentAttr *MFAA = RD->getAttr<MaxFieldAlignmentAttr>()){
2673
125
    unsigned PackedAlignment = MFAA->getAlignment();
2674
125
    if (PackedAlignment <= Context.getTargetInfo().getPointerWidth(0))
2675
92
      MaxFieldAlignment = Context.toCharUnitsFromBits(PackedAlignment);
2676
125
  }
2677
  // Packed attribute forces max field alignment to be 1.
2678
5.10k
  if (RD->hasAttr<PackedAttr>())
2679
61
    MaxFieldAlignment = CharUnits::One();
2680
2681
  // Try to respect the external layout if present.
2682
5.10k
  UseExternalLayout = false;
2683
5.10k
  if (ExternalASTSource *Source = Context.getExternalSource())
2684
266
    UseExternalLayout = Source->layoutRecordType(
2685
266
        RD, External.Size, External.Align, External.FieldOffsets,
2686
266
        External.BaseOffsets, External.VirtualBaseOffsets);
2687
5.10k
}
2688
2689
void
2690
4.77k
MicrosoftRecordLayoutBuilder::initializeCXXLayout(const CXXRecordDecl *RD) {
2691
4.77k
  EndsWithZeroSizedObject = false;
2692
4.77k
  LeadsWithZeroSizedBase = false;
2693
4.77k
  HasOwnVFPtr = false;
2694
4.77k
  HasVBPtr = false;
2695
4.77k
  PrimaryBase = nullptr;
2696
4.77k
  SharedVBPtrBase = nullptr;
2697
  // Calculate pointer size and alignment.  These are used for vfptr and vbprt
2698
  // injection.
2699
4.77k
  PointerInfo.Size =
2700
4.77k
      Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
2701
4.77k
  PointerInfo.Alignment =
2702
4.77k
      Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(0));
2703
  // Respect pragma pack.
2704
4.77k
  if (!MaxFieldAlignment.isZero())
2705
56
    PointerInfo.Alignment = std::min(PointerInfo.Alignment, MaxFieldAlignment);
2706
4.77k
}
2707
2708
void
2709
4.77k
MicrosoftRecordLayoutBuilder::layoutNonVirtualBases(const CXXRecordDecl *RD) {
2710
  // The MS-ABI lays out all bases that contain leading vfptrs before it lays
2711
  // out any bases that do not contain vfptrs.  We implement this as two passes
2712
  // over the bases.  This approach guarantees that the primary base is laid out
2713
  // first.  We use these passes to calculate some additional aggregated
2714
  // information about the bases, such as required alignment and the presence of
2715
  // zero sized members.
2716
4.77k
  const ASTRecordLayout *PreviousBaseLayout = nullptr;
2717
4.77k
  bool HasPolymorphicBaseClass = false;
2718
  // Iterate through the bases and lay out the non-virtual ones.
2719
2.49k
  for (const CXXBaseSpecifier &Base : RD->bases()) {
2720
2.49k
    const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2721
2.49k
    HasPolymorphicBaseClass |= BaseDecl->isPolymorphic();
2722
2.49k
    const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2723
    // Mark and skip virtual bases.
2724
2.49k
    if (Base.isVirtual()) {
2725
907
      HasVBPtr = true;
2726
907
      continue;
2727
907
    }
2728
    // Check for a base to share a VBPtr with.
2729
1.59k
    if (!SharedVBPtrBase && 
BaseLayout.hasVBPtr()1.46k
) {
2730
225
      SharedVBPtrBase = BaseDecl;
2731
225
      HasVBPtr = true;
2732
225
    }
2733
    // Only lay out bases with extendable VFPtrs on the first pass.
2734
1.59k
    if (!BaseLayout.hasExtendableVFPtr())
2735
1.07k
      continue;
2736
    // If we don't have a primary base, this one qualifies.
2737
521
    if (!PrimaryBase) {
2738
378
      PrimaryBase = BaseDecl;
2739
378
      LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
2740
378
    }
2741
    // Lay out the base.
2742
521
    layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
2743
521
  }
2744
  // Figure out if we need a fresh VFPtr for this class.
2745
4.77k
  if (RD->isPolymorphic()) {
2746
1.44k
    if (!HasPolymorphicBaseClass)
2747
      // This class introduces polymorphism, so we need a vftable to store the
2748
      // RTTI information.
2749
714
      HasOwnVFPtr = true;
2750
733
    else if (!PrimaryBase) {
2751
      // We have a polymorphic base class but can't extend its vftable. Add a
2752
      // new vfptr if we would use any vftable slots.
2753
1.62k
      for (CXXMethodDecl *M : RD->methods()) {
2754
1.62k
        if (MicrosoftVTableContext::hasVtableSlot(M) &&
2755
317
            M->size_overridden_methods() == 0) {
2756
82
          HasOwnVFPtr = true;
2757
82
          break;
2758
82
        }
2759
1.62k
      }
2760
355
    }
2761
1.44k
  }
2762
  // If we don't have a primary base then we have a leading object that could
2763
  // itself lead with a zero-sized object, something we track.
2764
4.77k
  bool CheckLeadingLayout = !PrimaryBase;
2765
  // Iterate through the bases and lay out the non-virtual ones.
2766
2.49k
  for (const CXXBaseSpecifier &Base : RD->bases()) {
2767
2.49k
    if (Base.isVirtual())
2768
907
      continue;
2769
1.59k
    const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2770
1.59k
    const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2771
    // Only lay out bases without extendable VFPtrs on the second pass.
2772
1.59k
    if (BaseLayout.hasExtendableVFPtr()) {
2773
521
      VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
2774
521
      continue;
2775
521
    }
2776
    // If this is the first layout, check to see if it leads with a zero sized
2777
    // object.  If it does, so do we.
2778
1.07k
    if (CheckLeadingLayout) {
2779
681
      CheckLeadingLayout = false;
2780
681
      LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
2781
681
    }
2782
    // Lay out the base.
2783
1.07k
    layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
2784
1.07k
    VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
2785
1.07k
  }
2786
  // Set our VBPtroffset if we know it at this point.
2787
4.77k
  if (!HasVBPtr)
2788
3.92k
    VBPtrOffset = CharUnits::fromQuantity(-1);
2789
850
  else if (SharedVBPtrBase) {
2790
225
    const ASTRecordLayout &Layout = Context.getASTRecordLayout(SharedVBPtrBase);
2791
225
    VBPtrOffset = Bases[SharedVBPtrBase] + Layout.getVBPtrOffset();
2792
225
  }
2793
4.77k
}
2794
2795
3.50k
static bool recordUsesEBO(const RecordDecl *RD) {
2796
3.50k
  if (!isa<CXXRecordDecl>(RD))
2797
20
    return false;
2798
3.48k
  if (RD->hasAttr<EmptyBasesAttr>())
2799
16
    return true;
2800
3.47k
  if (auto *LVA = RD->getAttr<LayoutVersionAttr>())
2801
    // TODO: Double check with the next version of MSVC.
2802
0
    if (LVA->getVersion() <= LangOptions::MSVC2015)
2803
0
      return false;
2804
  // TODO: Some later version of MSVC will change the default behavior of the
2805
  // compiler to enable EBO by default.  When this happens, we will need an
2806
  // additional isCompatibleWithMSVC check.
2807
3.47k
  return false;
2808
3.47k
}
2809
2810
void MicrosoftRecordLayoutBuilder::layoutNonVirtualBase(
2811
    const CXXRecordDecl *RD,
2812
    const CXXRecordDecl *BaseDecl,
2813
    const ASTRecordLayout &BaseLayout,
2814
1.59k
    const ASTRecordLayout *&PreviousBaseLayout) {
2815
  // Insert padding between two bases if the left first one is zero sized or
2816
  // contains a zero sized subobject and the right is zero sized or one leads
2817
  // with a zero sized base.
2818
1.59k
  bool MDCUsesEBO = recordUsesEBO(RD);
2819
1.59k
  if (PreviousBaseLayout && 
PreviousBaseLayout->endsWithZeroSizedObject()533
&&
2820
146
      BaseLayout.leadsWithZeroSizedBase() && 
!MDCUsesEBO111
)
2821
109
    Size++;
2822
1.59k
  ElementInfo Info = getAdjustedElementInfo(BaseLayout);
2823
1.59k
  CharUnits BaseOffset;
2824
2825
  // Respect the external AST source base offset, if present.
2826
1.59k
  bool FoundBase = false;
2827
1.59k
  if (UseExternalLayout) {
2828
2
    FoundBase = External.getExternalNVBaseOffset(BaseDecl, BaseOffset);
2829
2
    if (FoundBase) {
2830
0
      assert(BaseOffset >= Size && "base offset already allocated");
2831
0
      Size = BaseOffset;
2832
0
    }
2833
2
  }
2834
2835
1.59k
  if (!FoundBase) {
2836
1.59k
    if (MDCUsesEBO && 
BaseDecl->isEmpty()12
) {
2837
4
      assert(BaseLayout.getNonVirtualSize() == CharUnits::Zero());
2838
4
      BaseOffset = CharUnits::Zero();
2839
1.58k
    } else {
2840
      // Otherwise, lay the base out at the end of the MDC.
2841
1.58k
      BaseOffset = Size = Size.alignTo(Info.Alignment);
2842
1.58k
    }
2843
1.59k
  }
2844
1.59k
  Bases.insert(std::make_pair(BaseDecl, BaseOffset));
2845
1.59k
  Size += BaseLayout.getNonVirtualSize();
2846
1.59k
  PreviousBaseLayout = &BaseLayout;
2847
1.59k
}
2848
2849
5.10k
void MicrosoftRecordLayoutBuilder::layoutFields(const RecordDecl *RD) {
2850
5.10k
  LastFieldIsNonZeroWidthBitfield = false;
2851
5.10k
  for (const FieldDecl *Field : RD->fields())
2852
2.87k
    layoutField(Field);
2853
5.10k
}
2854
2855
2.87k
void MicrosoftRecordLayoutBuilder::layoutField(const FieldDecl *FD) {
2856
2.87k
  if (FD->isBitField()) {
2857
221
    layoutBitField(FD);
2858
221
    return;
2859
221
  }
2860
2.65k
  LastFieldIsNonZeroWidthBitfield = false;
2861
2.65k
  ElementInfo Info = getAdjustedElementInfo(FD);
2862
2.65k
  Alignment = std::max(Alignment, Info.Alignment);
2863
2.65k
  CharUnits FieldOffset;
2864
2.65k
  if (UseExternalLayout)
2865
6
    FieldOffset =
2866
6
        Context.toCharUnitsFromBits(External.getExternalFieldOffset(FD));
2867
2.64k
  else if (IsUnion)
2868
77
    FieldOffset = CharUnits::Zero();
2869
2.57k
  else
2870
2.57k
    FieldOffset = Size.alignTo(Info.Alignment);
2871
2.65k
  placeFieldAtOffset(FieldOffset);
2872
2.65k
  Size = std::max(Size, FieldOffset + Info.Size);
2873
2.65k
}
2874
2875
221
void MicrosoftRecordLayoutBuilder::layoutBitField(const FieldDecl *FD) {
2876
221
  unsigned Width = FD->getBitWidthValue(Context);
2877
221
  if (Width == 0) {
2878
43
    layoutZeroWidthBitField(FD);
2879
43
    return;
2880
43
  }
2881
178
  ElementInfo Info = getAdjustedElementInfo(FD);
2882
  // Clamp the bitfield to a containable size for the sake of being able
2883
  // to lay them out.  Sema will throw an error.
2884
178
  if (Width > Context.toBits(Info.Size))
2885
0
    Width = Context.toBits(Info.Size);
2886
  // Check to see if this bitfield fits into an existing allocation.  Note:
2887
  // MSVC refuses to pack bitfields of formal types with different sizes
2888
  // into the same allocation.
2889
178
  if (!UseExternalLayout && 
!IsUnion173
&&
LastFieldIsNonZeroWidthBitfield155
&&
2890
78
      CurrentBitfieldSize == Info.Size && 
Width <= RemainingBitsInField69
) {
2891
45
    placeFieldAtBitOffset(Context.toBits(Size) - RemainingBitsInField);
2892
45
    RemainingBitsInField -= Width;
2893
45
    return;
2894
45
  }
2895
133
  LastFieldIsNonZeroWidthBitfield = true;
2896
133
  CurrentBitfieldSize = Info.Size;
2897
133
  if (UseExternalLayout) {
2898
5
    auto FieldBitOffset = External.getExternalFieldOffset(FD);
2899
5
    placeFieldAtBitOffset(FieldBitOffset);
2900
5
    auto NewSize = Context.toCharUnitsFromBits(
2901
5
        llvm::alignDown(FieldBitOffset, Context.toBits(Info.Alignment)) +
2902
5
        Context.toBits(Info.Size));
2903
5
    Size = std::max(Size, NewSize);
2904
5
    Alignment = std::max(Alignment, Info.Alignment);
2905
128
  } else if (IsUnion) {
2906
18
    placeFieldAtOffset(CharUnits::Zero());
2907
18
    Size = std::max(Size, Info.Size);
2908
    // TODO: Add a Sema warning that MS ignores bitfield alignment in unions.
2909
110
  } else {
2910
    // Allocate a new block of memory and place the bitfield in it.
2911
110
    CharUnits FieldOffset = Size.alignTo(Info.Alignment);
2912
110
    placeFieldAtOffset(FieldOffset);
2913
110
    Size = FieldOffset + Info.Size;
2914
110
    Alignment = std::max(Alignment, Info.Alignment);
2915
110
    RemainingBitsInField = Context.toBits(Info.Size) - Width;
2916
110
  }
2917
133
}
2918
2919
void
2920
43
MicrosoftRecordLayoutBuilder::layoutZeroWidthBitField(const FieldDecl *FD) {
2921
  // Zero-width bitfields are ignored unless they follow a non-zero-width
2922
  // bitfield.
2923
43
  if (!LastFieldIsNonZeroWidthBitfield) {
2924
17
    placeFieldAtOffset(IsUnion ? 
CharUnits::Zero()4
: Size);
2925
    // TODO: Add a Sema warning that MS ignores alignment for zero
2926
    // sized bitfields that occur after zero-size bitfields or non-bitfields.
2927
21
    return;
2928
21
  }
2929
22
  LastFieldIsNonZeroWidthBitfield = false;
2930
22
  ElementInfo Info = getAdjustedElementInfo(FD);
2931
22
  if (IsUnion) {
2932
8
    placeFieldAtOffset(CharUnits::Zero());
2933
8
    Size = std::max(Size, Info.Size);
2934
    // TODO: Add a Sema warning that MS ignores bitfield alignment in unions.
2935
14
  } else {
2936
    // Round up the current record size to the field's alignment boundary.
2937
14
    CharUnits FieldOffset = Size.alignTo(Info.Alignment);
2938
14
    placeFieldAtOffset(FieldOffset);
2939
14
    Size = FieldOffset;
2940
14
    Alignment = std::max(Alignment, Info.Alignment);
2941
14
  }
2942
22
}
2943
2944
4.77k
void MicrosoftRecordLayoutBuilder::injectVBPtr(const CXXRecordDecl *RD) {
2945
4.77k
  if (!HasVBPtr || 
SharedVBPtrBase850
)
2946
4.14k
    return;
2947
  // Inject the VBPointer at the injection site.
2948
625
  CharUnits InjectionSite = VBPtrOffset;
2949
  // But before we do, make sure it's properly aligned.
2950
625
  VBPtrOffset = VBPtrOffset.alignTo(PointerInfo.Alignment);
2951
  // Determine where the first field should be laid out after the vbptr.
2952
625
  CharUnits FieldStart = VBPtrOffset + PointerInfo.Size;
2953
  // Shift everything after the vbptr down, unless we're using an external
2954
  // layout.
2955
625
  if (UseExternalLayout) {
2956
    // It is possible that there were no fields or bases located after vbptr,
2957
    // so the size was not adjusted before.
2958
2
    if (Size < FieldStart)
2959
1
      Size = FieldStart;
2960
2
    return;
2961
2
  }
2962
  // Make sure that the amount we push the fields back by is a multiple of the
2963
  // alignment.
2964
623
  CharUnits Offset = (FieldStart - InjectionSite)
2965
623
                         .alignTo(std::max(RequiredAlignment, Alignment));
2966
623
  Size += Offset;
2967
623
  for (uint64_t &FieldOffset : FieldOffsets)
2968
357
    FieldOffset += Context.toBits(Offset);
2969
623
  for (BaseOffsetsMapTy::value_type &Base : Bases)
2970
257
    if (Base.second >= InjectionSite)
2971
64
      Base.second += Offset;
2972
623
}
2973
2974
4.77k
void MicrosoftRecordLayoutBuilder::injectVFPtr(const CXXRecordDecl *RD) {
2975
4.77k
  if (!HasOwnVFPtr)
2976
3.97k
    return;
2977
  // Make sure that the amount we push the struct back by is a multiple of the
2978
  // alignment.
2979
796
  CharUnits Offset =
2980
796
      PointerInfo.Size.alignTo(std::max(RequiredAlignment, Alignment));
2981
  // Push back the vbptr, but increase the size of the object and push back
2982
  // regular fields by the offset only if not using external record layout.
2983
796
  if (HasVBPtr)
2984
110
    VBPtrOffset += Offset;
2985
2986
796
  if (UseExternalLayout) {
2987
    // The class may have no bases or fields, but still have a vfptr
2988
    // (e.g. it's an interface class). The size was not correctly set before
2989
    // in this case.
2990
2
    if (FieldOffsets.empty() && 
Bases.empty()1
)
2991
1
      Size += Offset;
2992
2
    return;
2993
2
  }
2994
2995
794
  Size += Offset;
2996
2997
  // If we're using an external layout, the fields offsets have already
2998
  // accounted for this adjustment.
2999
794
  for (uint64_t &FieldOffset : FieldOffsets)
3000
159
    FieldOffset += Context.toBits(Offset);
3001
794
  for (BaseOffsetsMapTy::value_type &Base : Bases)
3002
83
    Base.second += Offset;
3003
794
}
3004
3005
4.77k
void MicrosoftRecordLayoutBuilder::layoutVirtualBases(const CXXRecordDecl *RD) {
3006
4.77k
  if (!HasVBPtr)
3007
3.92k
    return;
3008
  // Vtordisps are always 4 bytes (even in 64-bit mode)
3009
850
  CharUnits VtorDispSize = CharUnits::fromQuantity(4);
3010
850
  CharUnits VtorDispAlignment = VtorDispSize;
3011
  // vtordisps respect pragma pack.
3012
850
  if (!MaxFieldAlignment.isZero())
3013
16
    VtorDispAlignment = std::min(VtorDispAlignment, MaxFieldAlignment);
3014
  // The alignment of the vtordisp is at least the required alignment of the
3015
  // entire record.  This requirement may be present to support vtordisp
3016
  // injection.
3017
1.26k
  for (const CXXBaseSpecifier &VBase : RD->vbases()) {
3018
1.26k
    const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
3019
1.26k
    const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
3020
1.26k
    RequiredAlignment =
3021
1.26k
        std::max(RequiredAlignment, BaseLayout.getRequiredAlignment());
3022
1.26k
  }
3023
850
  VtorDispAlignment = std::max(VtorDispAlignment, RequiredAlignment);
3024
  // Compute the vtordisp set.
3025
850
  llvm::SmallPtrSet<const CXXRecordDecl *, 2> HasVtorDispSet;
3026
850
  computeVtorDispSet(HasVtorDispSet, RD);
3027
  // Iterate through the virtual bases and lay them out.
3028
850
  const ASTRecordLayout *PreviousBaseLayout = nullptr;
3029
1.26k
  for (const CXXBaseSpecifier &VBase : RD->vbases()) {
3030
1.26k
    const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
3031
1.26k
    const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
3032
1.26k
    bool HasVtordisp = HasVtorDispSet.count(BaseDecl) > 0;
3033
    // Insert padding between two bases if the left first one is zero sized or
3034
    // contains a zero sized subobject and the right is zero sized or one leads
3035
    // with a zero sized base.  The padding between virtual bases is 4
3036
    // bytes (in both 32 and 64 bits modes) and always involves rounding up to
3037
    // the required alignment, we don't know why.
3038
1.26k
    if ((PreviousBaseLayout && 
PreviousBaseLayout->endsWithZeroSizedObject()413
&&
3039
165
         BaseLayout.leadsWithZeroSizedBase() && 
!recordUsesEBO(RD)116
) ||
3040
1.14k
        HasVtordisp) {
3041
274
      Size = Size.alignTo(VtorDispAlignment) + VtorDispSize;
3042
274
      Alignment = std::max(VtorDispAlignment, Alignment);
3043
274
    }
3044
    // Insert the virtual base.
3045
1.26k
    ElementInfo Info = getAdjustedElementInfo(BaseLayout);
3046
1.26k
    CharUnits BaseOffset;
3047
3048
    // Respect the external AST source base offset, if present.
3049
1.26k
    if (UseExternalLayout) {
3050
3
      if (!External.getExternalVBaseOffset(BaseDecl, BaseOffset))
3051
3
        BaseOffset = Size;
3052
3
    } else
3053
1.26k
      BaseOffset = Size.alignTo(Info.Alignment);
3054
3055
1.26k
    assert(BaseOffset >= Size && "base offset already allocated");
3056
3057
1.26k
    VBases.insert(std::make_pair(BaseDecl,
3058
1.26k
        ASTRecordLayout::VBaseInfo(BaseOffset, HasVtordisp)));
3059
1.26k
    Size = BaseOffset + BaseLayout.getNonVirtualSize();
3060
1.26k
    PreviousBaseLayout = &BaseLayout;
3061
1.26k
  }
3062
850
}
3063
3064
5.10k
void MicrosoftRecordLayoutBuilder::finalizeLayout(const RecordDecl *RD) {
3065
  // Respect required alignment.  Note that in 32-bit mode Required alignment
3066
  // may be 0 and cause size not to be updated.
3067
5.10k
  DataSize = Size;
3068
5.10k
  if (!RequiredAlignment.isZero()) {
3069
2.57k
    Alignment = std::max(Alignment, RequiredAlignment);
3070
2.57k
    auto RoundingAlignment = Alignment;
3071
2.57k
    if (!MaxFieldAlignment.isZero())
3072
132
      RoundingAlignment = std::min(RoundingAlignment, MaxFieldAlignment);
3073
2.57k
    RoundingAlignment = std::max(RoundingAlignment, RequiredAlignment);
3074
2.57k
    Size = Size.alignTo(RoundingAlignment);
3075
2.57k
  }
3076
5.10k
  if (Size.isZero()) {
3077
1.80k
    if (!recordUsesEBO(RD) || 
!cast<CXXRecordDecl>(RD)->isEmpty()4
) {
3078
1.79k
      EndsWithZeroSizedObject = true;
3079
1.79k
      LeadsWithZeroSizedBase = true;
3080
1.79k
    }
3081
    // Zero-sized structures have size equal to their alignment if a
3082
    // __declspec(align) came into play.
3083
1.80k
    if (RequiredAlignment >= MinEmptyStructSize)
3084
849
      Size = Alignment;
3085
951
    else
3086
951
      Size = MinEmptyStructSize;
3087
1.80k
  }
3088
3089
5.10k
  if (UseExternalLayout) {
3090
8
    Size = Context.toCharUnitsFromBits(External.Size);
3091
8
    if (External.Align)
3092
4
      Alignment = Context.toCharUnitsFromBits(External.Align);
3093
8
  }
3094
5.10k
}
3095
3096
// Recursively walks the non-virtual bases of a class and determines if any of
3097
// them are in the bases with overridden methods set.
3098
static bool
3099
RequiresVtordisp(const llvm::SmallPtrSetImpl<const CXXRecordDecl *> &
3100
                     BasesWithOverriddenMethods,
3101
669
                 const CXXRecordDecl *RD) {
3102
669
  if (BasesWithOverriddenMethods.count(RD))
3103
94
    return true;
3104
  // If any of a virtual bases non-virtual bases (recursively) requires a
3105
  // vtordisp than so does this virtual base.
3106
575
  for (const CXXBaseSpecifier &Base : RD->bases())
3107
87
    if (!Base.isVirtual() &&
3108
52
        RequiresVtordisp(BasesWithOverriddenMethods,
3109
52
                         Base.getType()->getAsCXXRecordDecl()))
3110
19
      return true;
3111
556
  return false;
3112
575
}
3113
3114
void MicrosoftRecordLayoutBuilder::computeVtorDispSet(
3115
    llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtordispSet,
3116
850
    const CXXRecordDecl *RD) const {
3117
  // /vd2 or #pragma vtordisp(2): Always use vtordisps for virtual bases with
3118
  // vftables.
3119
850
  if (RD->getMSVtorDispMode() == MSVtorDispMode::ForVFTable) {
3120
25
    for (const CXXBaseSpecifier &Base : RD->vbases()) {
3121
25
      const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
3122
25
      const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
3123
25
      if (Layout.hasExtendableVFPtr())
3124
23
        HasVtordispSet.insert(BaseDecl);
3125
25
    }
3126
20
    return;
3127
20
  }
3128
3129
  // If any of our bases need a vtordisp for this type, so do we.  Check our
3130
  // direct bases for vtordisp requirements.
3131
1.52k
  
for (const CXXBaseSpecifier &Base : RD->bases())830
{
3132
1.52k
    const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
3133
1.52k
    const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
3134
1.52k
    for (const auto &bi : Layout.getVBaseOffsetsMap())
3135
478
      if (bi.second.hasVtorDisp())
3136
43
        HasVtordispSet.insert(bi.first);
3137
1.52k
  }
3138
  // We don't introduce any additional vtordisps if either:
3139
  // * A user declared constructor or destructor aren't declared.
3140
  // * #pragma vtordisp(0) or the /vd0 flag are in use.
3141
830
  if ((!RD->hasUserDeclaredConstructor() && 
!RD->hasUserDeclaredDestructor()473
) ||
3142
420
      RD->getMSVtorDispMode() == MSVtorDispMode::Never)
3143
415
    return;
3144
  // /vd1 or #pragma vtordisp(1): Try to guess based on whether we think it's
3145
  // possible for a partially constructed object with virtual base overrides to
3146
  // escape a non-trivial constructor.
3147
415
  assert(RD->getMSVtorDispMode() == MSVtorDispMode::ForVBaseOverride);
3148
  // Compute a set of base classes which define methods we override.  A virtual
3149
  // base in this set will require a vtordisp.  A virtual base that transitively
3150
  // contains one of these bases as a non-virtual base will also require a
3151
  // vtordisp.
3152
415
  llvm::SmallPtrSet<const CXXMethodDecl *, 8> Work;
3153
415
  llvm::SmallPtrSet<const CXXRecordDecl *, 2> BasesWithOverriddenMethods;
3154
  // Seed the working set with our non-destructor, non-pure virtual methods.
3155
415
  for (const CXXMethodDecl *MD : RD->methods())
3156
2.08k
    if (MicrosoftVTableContext::hasVtableSlot(MD) &&
3157
258
        !isa<CXXDestructorDecl>(MD) && 
!MD->isPure()181
)
3158
179
      Work.insert(MD);
3159
723
  while (!Work.empty()) {
3160
308
    const CXXMethodDecl *MD = *Work.begin();
3161
308
    auto MethodRange = MD->overridden_methods();
3162
    // If a virtual method has no-overrides it lives in its parent's vtable.
3163
308
    if (MethodRange.begin() == MethodRange.end())
3164
192
      BasesWithOverriddenMethods.insert(MD->getParent());
3165
116
    else
3166
116
      Work.insert(MethodRange.begin(), MethodRange.end());
3167
    // We've finished processing this element, remove it from the working set.
3168
308
    Work.erase(MD);
3169
308
  }
3170
  // For each of our virtual bases, check if it is in the set of overridden
3171
  // bases or if it transitively contains a non-virtual base that is.
3172
649
  for (const CXXBaseSpecifier &Base : RD->vbases()) {
3173
649
    const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
3174
649
    if (!HasVtordispSet.count(BaseDecl) &&
3175
617
        RequiresVtordisp(BasesWithOverriddenMethods, BaseDecl))
3176
94
      HasVtordispSet.insert(BaseDecl);
3177
649
  }
3178
415
}
3179
3180
/// getASTRecordLayout - Get or compute information about the layout of the
3181
/// specified record (struct/union/class), which indicates its size and field
3182
/// position information.
3183
const ASTRecordLayout &
3184
4.78M
ASTContext::getASTRecordLayout(const RecordDecl *D) const {
3185
  // These asserts test different things.  A record has a definition
3186
  // as soon as we begin to parse the definition.  That definition is
3187
  // not a complete definition (which is what isDefinition() tests)
3188
  // until we *finish* parsing the definition.
3189
3190
4.78M
  if (D->hasExternalLexicalStorage() && 
!D->getDefinition()96.7k
)
3191
0
    getExternalSource()->CompleteType(const_cast<RecordDecl*>(D));
3192
3193
4.78M
  D = D->getDefinition();
3194
4.78M
  assert(D && "Cannot get layout of forward declarations!");
3195
4.78M
  assert(!D->isInvalidDecl() && "Cannot get layout of invalid decl!");
3196
4.78M
  assert(D->isCompleteDefinition() && "Cannot layout type before complete!");
3197
3198
  // Look up this layout, if already laid out, return what we have.
3199
  // Note that we can't save a reference to the entry because this function
3200
  // is recursive.
3201
4.78M
  const ASTRecordLayout *Entry = ASTRecordLayouts[D];
3202
4.78M
  if (Entry) 
return *Entry4.47M
;
3203
3204
312k
  const ASTRecordLayout *NewEntry = nullptr;
3205
3206
312k
  if (isMsLayout(*this)) {
3207
5.10k
    MicrosoftRecordLayoutBuilder Builder(*this);
3208
5.10k
    if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
3209
4.77k
      Builder.cxxLayout(RD);
3210
4.77k
      NewEntry = new (*this) ASTRecordLayout(
3211
4.77k
          *this, Builder.Size, Builder.Alignment, Builder.Alignment,
3212
4.77k
          Builder.Alignment, Builder.RequiredAlignment, Builder.HasOwnVFPtr,
3213
4.77k
          Builder.HasOwnVFPtr || 
Builder.PrimaryBase3.97k
, Builder.VBPtrOffset,
3214
4.77k
          Builder.DataSize, Builder.FieldOffsets, Builder.NonVirtualSize,
3215
4.77k
          Builder.Alignment, Builder.Alignment, CharUnits::Zero(),
3216
4.77k
          Builder.PrimaryBase, false, Builder.SharedVBPtrBase,
3217
4.77k
          Builder.EndsWithZeroSizedObject, Builder.LeadsWithZeroSizedBase,
3218
4.77k
          Builder.Bases, Builder.VBases);
3219
331
    } else {
3220
331
      Builder.layout(D);
3221
331
      NewEntry = new (*this) ASTRecordLayout(
3222
331
          *this, Builder.Size, Builder.Alignment, Builder.Alignment,
3223
331
          Builder.Alignment, Builder.RequiredAlignment, Builder.Size,
3224
331
          Builder.FieldOffsets);
3225
331
    }
3226
307k
  } else {
3227
307k
    if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
3228
186k
      EmptySubobjectMap EmptySubobjects(*this, RD);
3229
186k
      ItaniumRecordLayoutBuilder Builder(*this, &EmptySubobjects);
3230
186k
      Builder.Layout(RD);
3231
3232
      // In certain situations, we are allowed to lay out objects in the
3233
      // tail-padding of base classes.  This is ABI-dependent.
3234
      // FIXME: this should be stored in the record layout.
3235
186k
      bool skipTailPadding =
3236
186k
          mustSkipTailPadding(getTargetInfo().getCXXABI(), RD);
3237
3238
      // FIXME: This should be done in FinalizeLayout.
3239
186k
      CharUnits DataSize =
3240
103k
          skipTailPadding ? Builder.getSize() : 
Builder.getDataSize()83.5k
;
3241
186k
      CharUnits NonVirtualSize =
3242
103k
          skipTailPadding ? DataSize : 
Builder.NonVirtualSize83.5k
;
3243
186k
      NewEntry = new (*this) ASTRecordLayout(
3244
186k
          *this, Builder.getSize(), Builder.Alignment,
3245
186k
          Builder.PreferredAlignment, Builder.UnadjustedAlignment,
3246
          /*RequiredAlignment : used by MS-ABI)*/
3247
186k
          Builder.Alignment, Builder.HasOwnVFPtr, RD->isDynamicClass(),
3248
186k
          CharUnits::fromQuantity(-1), DataSize, Builder.FieldOffsets,
3249
186k
          NonVirtualSize, Builder.NonVirtualAlignment,
3250
186k
          Builder.PreferredNVAlignment,
3251
186k
          EmptySubobjects.SizeOfLargestEmptySubobject, Builder.PrimaryBase,
3252
186k
          Builder.PrimaryBaseIsVirtual, nullptr, false, false, Builder.Bases,
3253
186k
          Builder.VBases);
3254
120k
    } else {
3255
120k
      ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3256
120k
      Builder.Layout(D);
3257
3258
120k
      NewEntry = new (*this) ASTRecordLayout(
3259
120k
          *this, Builder.getSize(), Builder.Alignment,
3260
120k
          Builder.PreferredAlignment, Builder.UnadjustedAlignment,
3261
          /*RequiredAlignment : used by MS-ABI)*/
3262
120k
          Builder.Alignment, Builder.getSize(), Builder.FieldOffsets);
3263
120k
    }
3264
307k
  }
3265
3266
312k
  ASTRecordLayouts[D] = NewEntry;
3267
3268
312k
  if (getLangOpts().DumpRecordLayouts) {
3269
1.25k
    llvm::outs() << "\n*** Dumping AST Record Layout\n";
3270
1.25k
    DumpRecordLayout(D, llvm::outs(), getLangOpts().DumpRecordLayoutsSimple);
3271
1.25k
  }
3272
3273
312k
  return *NewEntry;
3274
312k
}
3275
3276
152k
const CXXMethodDecl *ASTContext::getCurrentKeyFunction(const CXXRecordDecl *RD) {
3277
152k
  if (!getTargetInfo().getCXXABI().hasKeyFunctions())
3278
3.38k
    return nullptr;
3279
3280
148k
  assert(RD->getDefinition() && "Cannot get key function for forward decl!");
3281
148k
  RD = RD->getDefinition();
3282
3283
  // Beware:
3284
  //  1) computing the key function might trigger deserialization, which might
3285
  //     invalidate iterators into KeyFunctions
3286
  //  2) 'get' on the LazyDeclPtr might also trigger deserialization and
3287
  //     invalidate the LazyDeclPtr within the map itself
3288
148k
  LazyDeclPtr Entry = KeyFunctions[RD];
3289
148k
  const Decl *Result =
3290
128k
      Entry ? 
Entry.get(getExternalSource())20.3k
: computeKeyFunction(*this, RD);
3291
3292
  // Store it back if it changed.
3293
148k
  if (Entry.isOffset() || Entry.isValid() != bool(Result))
3294
11.8k
    KeyFunctions[RD] = const_cast<Decl*>(Result);
3295
3296
148k
  return cast_or_null<CXXMethodDecl>(Result);
3297
148k
}
3298
3299
14
void ASTContext::setNonKeyFunction(const CXXMethodDecl *Method) {
3300
14
  assert(Method == Method->getFirstDecl() &&
3301
14
         "not working with method declaration from class definition");
3302
3303
  // Look up the cache entry.  Since we're working with the first
3304
  // declaration, its parent must be the class definition, which is
3305
  // the correct key for the KeyFunctions hash.
3306
14
  const auto &Map = KeyFunctions;
3307
14
  auto I = Map.find(Method->getParent());
3308
3309
  // If it's not cached, there's nothing to do.
3310
14
  if (I == Map.end()) 
return0
;
3311
3312
  // If it is cached, check whether it's the target method, and if so,
3313
  // remove it from the cache. Note, the call to 'get' might invalidate
3314
  // the iterator and the LazyDeclPtr object within the map.
3315
14
  LazyDeclPtr Ptr = I->second;
3316
14
  if (Ptr.get(getExternalSource()) == Method) {
3317
    // FIXME: remember that we did this for module / chained PCH state?
3318
14
    KeyFunctions.erase(Method->getParent());
3319
14
  }
3320
14
}
3321
3322
593
static uint64_t getFieldOffset(const ASTContext &C, const FieldDecl *FD) {
3323
593
  const ASTRecordLayout &Layout = C.getASTRecordLayout(FD->getParent());
3324
593
  return Layout.getFieldOffset(FD->getFieldIndex());
3325
593
}
3326
3327
553
uint64_t ASTContext::getFieldOffset(const ValueDecl *VD) const {
3328
553
  uint64_t OffsetInBits;
3329
553
  if (const FieldDecl *FD = dyn_cast<FieldDecl>(VD)) {
3330
527
    OffsetInBits = ::getFieldOffset(*this, FD);
3331
26
  } else {
3332
26
    const IndirectFieldDecl *IFD = cast<IndirectFieldDecl>(VD);
3333
3334
26
    OffsetInBits = 0;
3335
26
    for (const NamedDecl *ND : IFD->chain())
3336
66
      OffsetInBits += ::getFieldOffset(*this, cast<FieldDecl>(ND));
3337
26
  }
3338
3339
553
  return OffsetInBits;
3340
553
}
3341
3342
uint64_t ASTContext::lookupFieldBitOffset(const ObjCInterfaceDecl *OID,
3343
                                          const ObjCImplementationDecl *ID,
3344
3.40k
                                          const ObjCIvarDecl *Ivar) const {
3345
3.40k
  const ObjCInterfaceDecl *Container = Ivar->getContainingInterface();
3346
3347
  // FIXME: We should eliminate the need to have ObjCImplementationDecl passed
3348
  // in here; it should never be necessary because that should be the lexical
3349
  // decl context for the ivar.
3350
3351
  // If we know have an implementation (and the ivar is in it) then
3352
  // look up in the implementation layout.
3353
3.40k
  const ASTRecordLayout *RL;
3354
3.40k
  if (ID && 
declaresSameEntity(ID->getClassInterface(), Container)2.52k
)
3355
2.46k
    RL = &getASTObjCImplementationLayout(ID);
3356
932
  else
3357
932
    RL = &getASTObjCInterfaceLayout(Container);
3358
3359
  // Compute field index.
3360
  //
3361
  // FIXME: The index here is closely tied to how ASTContext::getObjCLayout is
3362
  // implemented. This should be fixed to get the information from the layout
3363
  // directly.
3364
3.40k
  unsigned Index = 0;
3365
3366
3.40k
  for (const ObjCIvarDecl *IVD = Container->all_declared_ivar_begin();
3367
8.88k
       IVD; 
IVD = IVD->getNextIvar()5.48k
) {
3368
8.88k
    if (Ivar == IVD)
3369
3.40k
      break;
3370
5.48k
    ++Index;
3371
5.48k
  }
3372
3.40k
  assert(Index < RL->getFieldCount() && "Ivar is not inside record layout!");
3373
3374
3.40k
  return RL->getFieldOffset(Index);
3375
3.40k
}
3376
3377
/// getObjCLayout - Get or compute information about the layout of the
3378
/// given interface.
3379
///
3380
/// \param Impl - If given, also include the layout of the interface's
3381
/// implementation. This may differ by including synthesized ivars.
3382
const ASTRecordLayout &
3383
ASTContext::getObjCLayout(const ObjCInterfaceDecl *D,
3384
19.5k
                          const ObjCImplementationDecl *Impl) const {
3385
  // Retrieve the definition
3386
19.5k
  if (D->hasExternalLexicalStorage() && 
!D->getDefinition()104
)
3387
0
    getExternalSource()->CompleteType(const_cast<ObjCInterfaceDecl*>(D));
3388
19.5k
  D = D->getDefinition();
3389
19.5k
  assert(D && !D->isInvalidDecl() && D->isThisDeclarationADefinition() &&
3390
19.5k
         "Invalid interface decl!");
3391
3392
  // Look up this layout, if already laid out, return what we have.
3393
19.5k
  const ObjCContainerDecl *Key =
3394
15.9k
    Impl ? 
(const ObjCContainerDecl*) Impl3.58k
: (const ObjCContainerDecl*) D;
3395
19.5k
  if (const ASTRecordLayout *Entry = ObjCLayouts[Key])
3396
11.8k
    return *Entry;
3397
3398
  // Add in synthesized ivar count if laying out an implementation.
3399
7.66k
  if (Impl) {
3400
2.59k
    unsigned SynthCount = CountNonClassIvars(D);
3401
    // If there aren't any synthesized ivars then reuse the interface
3402
    // entry. Note we can't cache this because we simply free all
3403
    // entries later; however we shouldn't look up implementations
3404
    // frequently.
3405
2.59k
    if (SynthCount == 0)
3406
2.35k
      return getObjCLayout(D, nullptr);
3407
5.31k
  }
3408
3409
5.31k
  ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3410
5.31k
  Builder.Layout(D);
3411
3412
5.31k
  const ASTRecordLayout *NewEntry = new (*this) ASTRecordLayout(
3413
5.31k
      *this, Builder.getSize(), Builder.Alignment, Builder.PreferredAlignment,
3414
5.31k
      Builder.UnadjustedAlignment,
3415
      /*RequiredAlignment : used by MS-ABI)*/
3416
5.31k
      Builder.Alignment, Builder.getDataSize(), Builder.FieldOffsets);
3417
3418
5.31k
  ObjCLayouts[Key] = NewEntry;
3419
3420
5.31k
  return *NewEntry;
3421
5.31k
}
3422
3423
static void PrintOffset(raw_ostream &OS,
3424
5.37k
                        CharUnits Offset, unsigned IndentLevel) {
3425
5.37k
  OS << llvm::format("%10" PRId64 " | ", (int64_t)Offset.getQuantity());
3426
5.37k
  OS.indent(IndentLevel * 2);
3427
5.37k
}
3428
3429
static void PrintBitFieldOffset(raw_ostream &OS, CharUnits Offset,
3430
                                unsigned Begin, unsigned Width,
3431
322
                                unsigned IndentLevel) {
3432
322
  llvm::SmallString<10> Buffer;
3433
322
  {
3434
322
    llvm::raw_svector_ostream BufferOS(Buffer);
3435
322
    BufferOS << Offset.getQuantity() << ':';
3436
322
    if (Width == 0) {
3437
62
      BufferOS << '-';
3438
260
    } else {
3439
260
      BufferOS << Begin << '-' << (Begin + Width - 1);
3440
260
    }
3441
322
  }
3442
3443
322
  OS << llvm::right_justify(Buffer, 10) << " | ";
3444
322
  OS.indent(IndentLevel * 2);
3445
322
}
3446
3447
2.23k
static void PrintIndentNoOffset(raw_ostream &OS, unsigned IndentLevel) {
3448
2.23k
  OS << "           | ";
3449
2.23k
  OS.indent(IndentLevel * 2);
3450
2.23k
}
3451
3452
static void DumpRecordLayout(raw_ostream &OS, const RecordDecl *RD,
3453
                             const ASTContext &C,
3454
                             CharUnits Offset,
3455
                             unsigned IndentLevel,
3456
                             const char* Description,
3457
                             bool PrintSizeInfo,
3458
2.75k
                             bool IncludeVirtualBases) {
3459
2.75k
  const ASTRecordLayout &Layout = C.getASTRecordLayout(RD);
3460
2.75k
  auto CXXRD = dyn_cast<CXXRecordDecl>(RD);
3461
3462
2.75k
  PrintOffset(OS, Offset, IndentLevel);
3463
2.75k
  OS << C.getTypeDeclType(const_cast<RecordDecl*>(RD)).getAsString();
3464
2.75k
  if (Description)
3465
1.58k
    OS << ' ' << Description;
3466
2.75k
  if (CXXRD && 
CXXRD->isEmpty()2.64k
)
3467
815
    OS << " (empty)";
3468
2.75k
  OS << '\n';
3469
3470
2.75k
  IndentLevel++;
3471
3472
  // Dump bases.
3473
2.75k
  if (CXXRD) {
3474
2.64k
    const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
3475
2.64k
    bool HasOwnVFPtr = Layout.hasOwnVFPtr();
3476
2.64k
    bool HasOwnVBPtr = Layout.hasOwnVBPtr();
3477
3478
    // Vtable pointer.
3479
2.64k
    if (CXXRD->isDynamicClass() && 
!PrimaryBase793
&&
!isMsLayout(C)736
) {
3480
17
      PrintOffset(OS, Offset, IndentLevel);
3481
17
      OS << '(' << *RD << " vtable pointer)\n";
3482
2.62k
    } else if (HasOwnVFPtr) {
3483
345
      PrintOffset(OS, Offset, IndentLevel);
3484
      // vfptr (for Microsoft C++ ABI)
3485
345
      OS << '(' << *RD << " vftable pointer)\n";
3486
345
    }
3487
3488
    // Collect nvbases.
3489
2.64k
    SmallVector<const CXXRecordDecl *, 4> Bases;
3490
1.40k
    for (const CXXBaseSpecifier &Base : CXXRD->bases()) {
3491
1.40k
      assert(!Base.getType()->isDependentType() &&
3492
1.40k
             "Cannot layout class with dependent bases.");
3493
1.40k
      if (!Base.isVirtual())
3494
773
        Bases.push_back(Base.getType()->getAsCXXRecordDecl());
3495
1.40k
    }
3496
3497
    // Sort nvbases by offset.
3498
2.64k
    llvm::stable_sort(
3499
312
        Bases, [&](const CXXRecordDecl *L, const CXXRecordDecl *R) {
3500
312
          return Layout.getBaseClassOffset(L) < Layout.getBaseClassOffset(R);
3501
312
        });
3502
3503
    // Dump (non-virtual) bases
3504
773
    for (const CXXRecordDecl *Base : Bases) {
3505
773
      CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base);
3506
773
      DumpRecordLayout(OS, Base, C, BaseOffset, IndentLevel,
3507
716
                       Base == PrimaryBase ? 
"(primary base)"57
: "(base)",
3508
773
                       /*PrintSizeInfo=*/false,
3509
773
                       /*IncludeVirtualBases=*/false);
3510
773
    }
3511
3512
    // vbptr (for Microsoft C++ ABI)
3513
2.64k
    if (HasOwnVBPtr) {
3514
406
      PrintOffset(OS, Offset + Layout.getVBPtrOffset(), IndentLevel);
3515
406
      OS << '(' << *RD << " vbtable pointer)\n";
3516
406
    }
3517
2.64k
  }
3518
3519
  // Dump fields.
3520
2.75k
  uint64_t FieldNo = 0;
3521
2.75k
  for (RecordDecl::field_iterator I = RD->field_begin(),
3522
5.04k
         E = RD->field_end(); I != E; 
++I, ++FieldNo2.28k
) {
3523
2.28k
    const FieldDecl &Field = **I;
3524
2.28k
    uint64_t LocalFieldOffsetInBits = Layout.getFieldOffset(FieldNo);
3525
2.28k
    CharUnits FieldOffset =
3526
2.28k
      Offset + C.toCharUnitsFromBits(LocalFieldOffsetInBits);
3527
3528
    // Recursively dump fields of record type.
3529
2.28k
    if (auto RT = Field.getType()->getAs<RecordType>()) {
3530
189
      DumpRecordLayout(OS, RT->getDecl(), C, FieldOffset, IndentLevel,
3531
189
                       Field.getName().data(),
3532
189
                       /*PrintSizeInfo=*/false,
3533
189
                       /*IncludeVirtualBases=*/true);
3534
189
      continue;
3535
189
    }
3536
3537
2.09k
    if (Field.isBitField()) {
3538
322
      uint64_t LocalFieldByteOffsetInBits = C.toBits(FieldOffset - Offset);
3539
322
      unsigned Begin = LocalFieldOffsetInBits - LocalFieldByteOffsetInBits;
3540
322
      unsigned Width = Field.getBitWidthValue(C);
3541
322
      PrintBitFieldOffset(OS, FieldOffset, Begin, Width, IndentLevel);
3542
1.77k
    } else {
3543
1.77k
      PrintOffset(OS, FieldOffset, IndentLevel);
3544
1.77k
    }
3545
2.09k
    OS << Field.getType().getAsString() << ' ' << Field << '\n';
3546
2.09k
  }
3547
3548
  // Dump virtual bases.
3549
2.75k
  if (CXXRD && 
IncludeVirtualBases2.64k
) {
3550
1.24k
    const ASTRecordLayout::VBaseOffsetsMapTy &VtorDisps =
3551
1.24k
      Layout.getVBaseOffsetsMap();
3552
3553
620
    for (const CXXBaseSpecifier &Base : CXXRD->vbases()) {
3554
620
      assert(Base.isVirtual() && "Found non-virtual class!");
3555
620
      const CXXRecordDecl *VBase = Base.getType()->getAsCXXRecordDecl();
3556
3557
620
      CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBase);
3558
3559
620
      if (VtorDisps.find(VBase)->second.hasVtorDisp()) {
3560
74
        PrintOffset(OS, VBaseOffset - CharUnits::fromQuantity(4), IndentLevel);
3561
74
        OS << "(vtordisp for vbase " << *VBase << ")\n";
3562
74
      }
3563
3564
620
      DumpRecordLayout(OS, VBase, C, VBaseOffset, IndentLevel,
3565
620
                       VBase == Layout.getPrimaryBase() ?
3566
620
                         
"(primary virtual base)"0
: "(virtual base)",
3567
620
                       /*PrintSizeInfo=*/false,
3568
620
                       /*IncludeVirtualBases=*/false);
3569
620
    }
3570
1.24k
  }
3571
3572
2.75k
  if (!PrintSizeInfo) 
return1.58k
;
3573
3574
1.17k
  PrintIndentNoOffset(OS, IndentLevel - 1);
3575
1.17k
  OS << "[sizeof=" << Layout.getSize().getQuantity();
3576
1.17k
  if (CXXRD && 
!isMsLayout(C)1.05k
)
3577
194
    OS << ", dsize=" << Layout.getDataSize().getQuantity();
3578
1.17k
  OS << ", align=" << Layout.getAlignment().getQuantity();
3579
1.17k
  if (C.getTargetInfo().defaultsToAIXPowerAlignment())
3580
156
    OS << ", preferredalign=" << Layout.getPreferredAlignment().getQuantity();
3581
3582
1.17k
  if (CXXRD) {
3583
1.05k
    OS << ",\n";
3584
1.05k
    PrintIndentNoOffset(OS, IndentLevel - 1);
3585
1.05k
    OS << " nvsize=" << Layout.getNonVirtualSize().getQuantity();
3586
1.05k
    OS << ", nvalign=" << Layout.getNonVirtualAlignment().getQuantity();
3587
1.05k
    if (C.getTargetInfo().defaultsToAIXPowerAlignment())
3588
152
      OS << ", preferrednvalign="
3589
152
         << Layout.getPreferredNVAlignment().getQuantity();
3590
1.05k
  }
3591
1.17k
  OS << "]\n";
3592
1.17k
}
3593
3594
void ASTContext::DumpRecordLayout(const RecordDecl *RD, raw_ostream &OS,
3595
1.25k
                                  bool Simple) const {
3596
1.25k
  if (!Simple) {
3597
1.17k
    ::DumpRecordLayout(OS, RD, *this, CharUnits(), 0, nullptr,
3598
1.17k
                       /*PrintSizeInfo*/ true,
3599
1.17k
                       /*IncludeVirtualBases=*/true);
3600
1.17k
    return;
3601
1.17k
  }
3602
3603
  // The "simple" format is designed to be parsed by the
3604
  // layout-override testing code.  There shouldn't be any external
3605
  // uses of this format --- when LLDB overrides a layout, it sets up
3606
  // the data structures directly --- so feel free to adjust this as
3607
  // you like as long as you also update the rudimentary parser for it
3608
  // in libFrontend.
3609
3610
83
  const ASTRecordLayout &Info = getASTRecordLayout(RD);
3611
83
  OS << "Type: " << getTypeDeclType(RD).getAsString() << "\n";
3612
83
  OS << "\nLayout: ";
3613
83
  OS << "<ASTRecordLayout\n";
3614
83
  OS << "  Size:" << toBits(Info.getSize()) << "\n";
3615
83
  if (!isMsLayout(*this))
3616
72
    OS << "  DataSize:" << toBits(Info.getDataSize()) << "\n";
3617
83
  OS << "  Alignment:" << toBits(Info.getAlignment()) << "\n";
3618
83
  if (Target->defaultsToAIXPowerAlignment())
3619
0
    OS << "  PreferredAlignment:" << toBits(Info.getPreferredAlignment())
3620
0
       << "\n";
3621
83
  OS << "  FieldOffsets: [";
3622
270
  for (unsigned i = 0, e = Info.getFieldCount(); i != e; 
++i187
) {
3623
187
    if (i)
3624
111
      OS << ", ";
3625
187
    OS << Info.getFieldOffset(i);
3626
187
  }
3627
83
  OS << "]>\n";
3628
83
}