clang  16.0.0git
RecordLayoutBuilder.cpp
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1 //=== RecordLayoutBuilder.cpp - Helper class for building record layouts ---==//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "clang/AST/ASTContext.h"
11 #include "clang/AST/Attr.h"
13 #include "clang/AST/Decl.h"
14 #include "clang/AST/DeclCXX.h"
15 #include "clang/AST/DeclObjC.h"
16 #include "clang/AST/Expr.h"
18 #include "clang/AST/RecordLayout.h"
19 #include "clang/Basic/TargetInfo.h"
20 #include "llvm/ADT/SmallSet.h"
21 #include "llvm/Support/Format.h"
22 #include "llvm/Support/MathExtras.h"
23 
24 using namespace clang;
25 
26 namespace {
27 
28 /// BaseSubobjectInfo - Represents a single base subobject in a complete class.
29 /// For a class hierarchy like
30 ///
31 /// class A { };
32 /// class B : A { };
33 /// class C : A, B { };
34 ///
35 /// The BaseSubobjectInfo graph for C will have three BaseSubobjectInfo
36 /// instances, one for B and two for A.
37 ///
38 /// If a base is virtual, it will only have one BaseSubobjectInfo allocated.
39 struct BaseSubobjectInfo {
40  /// Class - The class for this base info.
41  const CXXRecordDecl *Class;
42 
43  /// IsVirtual - Whether the BaseInfo represents a virtual base or not.
44  bool IsVirtual;
45 
46  /// Bases - Information about the base subobjects.
48 
49  /// PrimaryVirtualBaseInfo - Holds the base info for the primary virtual base
50  /// of this base info (if one exists).
51  BaseSubobjectInfo *PrimaryVirtualBaseInfo;
52 
53  // FIXME: Document.
54  const BaseSubobjectInfo *Derived;
55 };
56 
57 /// Externally provided layout. Typically used when the AST source, such
58 /// as DWARF, lacks all the information that was available at compile time, such
59 /// as alignment attributes on fields and pragmas in effect.
60 struct ExternalLayout {
61  ExternalLayout() : 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;
74 
75  /// Virtual base offsets.
76  llvm::DenseMap<const CXXRecordDecl *, CharUnits> VirtualBaseOffsets;
77 
78  /// Get the offset of the given field. The external source must provide
79  /// entries for all fields in the record.
80  uint64_t getExternalFieldOffset(const FieldDecl *FD) {
81  assert(FieldOffsets.count(FD) &&
82  "Field does not have an external offset");
83  return FieldOffsets[FD];
84  }
85 
86  bool getExternalNVBaseOffset(const CXXRecordDecl *RD, CharUnits &BaseOffset) {
87  auto Known = BaseOffsets.find(RD);
88  if (Known == BaseOffsets.end())
89  return false;
90  BaseOffset = Known->second;
91  return true;
92  }
93 
94  bool getExternalVBaseOffset(const CXXRecordDecl *RD, CharUnits &BaseOffset) {
95  auto Known = VirtualBaseOffsets.find(RD);
96  if (Known == VirtualBaseOffsets.end())
97  return false;
98  BaseOffset = Known->second;
99  return true;
100  }
101 };
102 
103 /// EmptySubobjectMap - Keeps track of which empty subobjects exist at different
104 /// offsets while laying out a C++ class.
105 class EmptySubobjectMap {
106  const ASTContext &Context;
107  uint64_t CharWidth;
108 
109  /// Class - The class whose empty entries we're keeping track of.
110  const CXXRecordDecl *Class;
111 
112  /// EmptyClassOffsets - A map from offsets to empty record decls.
113  typedef llvm::TinyPtrVector<const CXXRecordDecl *> ClassVectorTy;
114  typedef llvm::DenseMap<CharUnits, ClassVectorTy> EmptyClassOffsetsMapTy;
115  EmptyClassOffsetsMapTy EmptyClassOffsets;
116 
117  /// MaxEmptyClassOffset - The highest offset known to contain an empty
118  /// base subobject.
119  CharUnits MaxEmptyClassOffset;
120 
121  /// ComputeEmptySubobjectSizes - Compute the size of the largest base or
122  /// member subobject that is empty.
123  void ComputeEmptySubobjectSizes();
124 
125  void AddSubobjectAtOffset(const CXXRecordDecl *RD, CharUnits Offset);
126 
127  void UpdateEmptyBaseSubobjects(const BaseSubobjectInfo *Info,
128  CharUnits Offset, bool PlacingEmptyBase);
129 
130  void UpdateEmptyFieldSubobjects(const CXXRecordDecl *RD,
131  const CXXRecordDecl *Class, CharUnits Offset,
132  bool PlacingOverlappingField);
133  void UpdateEmptyFieldSubobjects(const FieldDecl *FD, CharUnits Offset,
134  bool PlacingOverlappingField);
135 
136  /// AnyEmptySubobjectsBeyondOffset - Returns whether there are any empty
137  /// subobjects beyond the given offset.
138  bool AnyEmptySubobjectsBeyondOffset(CharUnits Offset) const {
139  return Offset <= MaxEmptyClassOffset;
140  }
141 
142  CharUnits
143  getFieldOffset(const ASTRecordLayout &Layout, unsigned FieldNo) const {
144  uint64_t FieldOffset = Layout.getFieldOffset(FieldNo);
145  assert(FieldOffset % CharWidth == 0 &&
146  "Field offset not at char boundary!");
147 
148  return Context.toCharUnitsFromBits(FieldOffset);
149  }
150 
151 protected:
152  bool CanPlaceSubobjectAtOffset(const CXXRecordDecl *RD,
153  CharUnits Offset) const;
154 
155  bool CanPlaceBaseSubobjectAtOffset(const BaseSubobjectInfo *Info,
156  CharUnits Offset);
157 
158  bool CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD,
159  const CXXRecordDecl *Class,
160  CharUnits Offset) const;
161  bool CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD,
162  CharUnits Offset) const;
163 
164 public:
165  /// This holds the size of the largest empty subobject (either a base
166  /// or a member). Will be zero if the record being built doesn't contain
167  /// any empty classes.
168  CharUnits SizeOfLargestEmptySubobject;
169 
170  EmptySubobjectMap(const ASTContext &Context, const CXXRecordDecl *Class)
171  : Context(Context), CharWidth(Context.getCharWidth()), Class(Class) {
172  ComputeEmptySubobjectSizes();
173  }
174 
175  /// CanPlaceBaseAtOffset - Return whether the given base class can be placed
176  /// at the given offset.
177  /// Returns false if placing the record will result in two components
178  /// (direct or indirect) of the same type having the same offset.
179  bool CanPlaceBaseAtOffset(const BaseSubobjectInfo *Info,
180  CharUnits Offset);
181 
182  /// CanPlaceFieldAtOffset - Return whether a field can be placed at the given
183  /// offset.
184  bool CanPlaceFieldAtOffset(const FieldDecl *FD, CharUnits Offset);
185 };
186 
187 void EmptySubobjectMap::ComputeEmptySubobjectSizes() {
188  // Check the bases.
189  for (const CXXBaseSpecifier &Base : Class->bases()) {
190  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
191 
192  CharUnits EmptySize;
193  const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
194  if (BaseDecl->isEmpty()) {
195  // If the class decl is empty, get its size.
196  EmptySize = Layout.getSize();
197  } else {
198  // Otherwise, we get the largest empty subobject for the decl.
199  EmptySize = Layout.getSizeOfLargestEmptySubobject();
200  }
201 
202  if (EmptySize > SizeOfLargestEmptySubobject)
203  SizeOfLargestEmptySubobject = EmptySize;
204  }
205 
206  // Check the fields.
207  for (const FieldDecl *FD : Class->fields()) {
208  const RecordType *RT =
209  Context.getBaseElementType(FD->getType())->getAs<RecordType>();
210 
211  // We only care about record types.
212  if (!RT)
213  continue;
214 
215  CharUnits EmptySize;
216  const CXXRecordDecl *MemberDecl = RT->getAsCXXRecordDecl();
217  const ASTRecordLayout &Layout = Context.getASTRecordLayout(MemberDecl);
218  if (MemberDecl->isEmpty()) {
219  // If the class decl is empty, get its size.
220  EmptySize = Layout.getSize();
221  } else {
222  // Otherwise, we get the largest empty subobject for the decl.
223  EmptySize = Layout.getSizeOfLargestEmptySubobject();
224  }
225 
226  if (EmptySize > SizeOfLargestEmptySubobject)
227  SizeOfLargestEmptySubobject = EmptySize;
228  }
229 }
230 
231 bool
232 EmptySubobjectMap::CanPlaceSubobjectAtOffset(const CXXRecordDecl *RD,
233  CharUnits Offset) const {
234  // We only need to check empty bases.
235  if (!RD->isEmpty())
236  return true;
237 
238  EmptyClassOffsetsMapTy::const_iterator I = EmptyClassOffsets.find(Offset);
239  if (I == EmptyClassOffsets.end())
240  return true;
241 
242  const ClassVectorTy &Classes = I->second;
243  if (!llvm::is_contained(Classes, RD))
244  return true;
245 
246  // There is already an empty class of the same type at this offset.
247  return false;
248 }
249 
250 void EmptySubobjectMap::AddSubobjectAtOffset(const CXXRecordDecl *RD,
251  CharUnits Offset) {
252  // We only care about empty bases.
253  if (!RD->isEmpty())
254  return;
255 
256  // If we have empty structures inside a union, we can assign both
257  // the same offset. Just avoid pushing them twice in the list.
258  ClassVectorTy &Classes = EmptyClassOffsets[Offset];
259  if (llvm::is_contained(Classes, RD))
260  return;
261 
262  Classes.push_back(RD);
263 
264  // Update the empty class offset.
265  if (Offset > MaxEmptyClassOffset)
266  MaxEmptyClassOffset = Offset;
267 }
268 
269 bool
270 EmptySubobjectMap::CanPlaceBaseSubobjectAtOffset(const BaseSubobjectInfo *Info,
271  CharUnits Offset) {
272  // We don't have to keep looking past the maximum offset that's known to
273  // contain an empty class.
274  if (!AnyEmptySubobjectsBeyondOffset(Offset))
275  return true;
276 
277  if (!CanPlaceSubobjectAtOffset(Info->Class, Offset))
278  return false;
279 
280  // Traverse all non-virtual bases.
281  const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
282  for (const BaseSubobjectInfo *Base : Info->Bases) {
283  if (Base->IsVirtual)
284  continue;
285 
286  CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
287 
288  if (!CanPlaceBaseSubobjectAtOffset(Base, BaseOffset))
289  return false;
290  }
291 
292  if (Info->PrimaryVirtualBaseInfo) {
293  BaseSubobjectInfo *PrimaryVirtualBaseInfo = Info->PrimaryVirtualBaseInfo;
294 
295  if (Info == PrimaryVirtualBaseInfo->Derived) {
296  if (!CanPlaceBaseSubobjectAtOffset(PrimaryVirtualBaseInfo, Offset))
297  return false;
298  }
299  }
300 
301  // Traverse all member variables.
302  unsigned FieldNo = 0;
303  for (CXXRecordDecl::field_iterator I = Info->Class->field_begin(),
304  E = Info->Class->field_end(); I != E; ++I, ++FieldNo) {
305  if (I->isBitField())
306  continue;
307 
308  CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
309  if (!CanPlaceFieldSubobjectAtOffset(*I, FieldOffset))
310  return false;
311  }
312 
313  return true;
314 }
315 
316 void EmptySubobjectMap::UpdateEmptyBaseSubobjects(const BaseSubobjectInfo *Info,
318  bool PlacingEmptyBase) {
319  if (!PlacingEmptyBase && Offset >= SizeOfLargestEmptySubobject) {
320  // We know that the only empty subobjects that can conflict with empty
321  // subobject of non-empty bases, are empty bases that can be placed at
322  // offset zero. Because of this, we only need to keep track of empty base
323  // subobjects with offsets less than the size of the largest empty
324  // subobject for our class.
325  return;
326  }
327 
328  AddSubobjectAtOffset(Info->Class, Offset);
329 
330  // Traverse all non-virtual bases.
331  const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
332  for (const BaseSubobjectInfo *Base : Info->Bases) {
333  if (Base->IsVirtual)
334  continue;
335 
336  CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
337  UpdateEmptyBaseSubobjects(Base, BaseOffset, PlacingEmptyBase);
338  }
339 
340  if (Info->PrimaryVirtualBaseInfo) {
341  BaseSubobjectInfo *PrimaryVirtualBaseInfo = Info->PrimaryVirtualBaseInfo;
342 
343  if (Info == PrimaryVirtualBaseInfo->Derived)
344  UpdateEmptyBaseSubobjects(PrimaryVirtualBaseInfo, Offset,
345  PlacingEmptyBase);
346  }
347 
348  // Traverse all member variables.
349  unsigned FieldNo = 0;
350  for (CXXRecordDecl::field_iterator I = Info->Class->field_begin(),
351  E = Info->Class->field_end(); I != E; ++I, ++FieldNo) {
352  if (I->isBitField())
353  continue;
354 
355  CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
356  UpdateEmptyFieldSubobjects(*I, FieldOffset, PlacingEmptyBase);
357  }
358 }
359 
360 bool EmptySubobjectMap::CanPlaceBaseAtOffset(const BaseSubobjectInfo *Info,
361  CharUnits Offset) {
362  // If we know this class doesn't have any empty subobjects we don't need to
363  // bother checking.
364  if (SizeOfLargestEmptySubobject.isZero())
365  return true;
366 
367  if (!CanPlaceBaseSubobjectAtOffset(Info, Offset))
368  return false;
369 
370  // We are able to place the base at this offset. Make sure to update the
371  // empty base subobject map.
372  UpdateEmptyBaseSubobjects(Info, Offset, Info->Class->isEmpty());
373  return true;
374 }
375 
376 bool
377 EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD,
378  const CXXRecordDecl *Class,
379  CharUnits Offset) const {
380  // We don't have to keep looking past the maximum offset that's known to
381  // contain an empty class.
382  if (!AnyEmptySubobjectsBeyondOffset(Offset))
383  return true;
384 
385  if (!CanPlaceSubobjectAtOffset(RD, Offset))
386  return false;
387 
388  const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
389 
390  // Traverse all non-virtual bases.
391  for (const CXXBaseSpecifier &Base : RD->bases()) {
392  if (Base.isVirtual())
393  continue;
394 
395  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
396 
397  CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(BaseDecl);
398  if (!CanPlaceFieldSubobjectAtOffset(BaseDecl, Class, BaseOffset))
399  return false;
400  }
401 
402  if (RD == Class) {
403  // This is the most derived class, traverse virtual bases as well.
404  for (const CXXBaseSpecifier &Base : RD->vbases()) {
405  const CXXRecordDecl *VBaseDecl = Base.getType()->getAsCXXRecordDecl();
406 
407  CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBaseDecl);
408  if (!CanPlaceFieldSubobjectAtOffset(VBaseDecl, Class, VBaseOffset))
409  return false;
410  }
411  }
412 
413  // Traverse all member variables.
414  unsigned FieldNo = 0;
415  for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
416  I != E; ++I, ++FieldNo) {
417  if (I->isBitField())
418  continue;
419 
420  CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
421 
422  if (!CanPlaceFieldSubobjectAtOffset(*I, FieldOffset))
423  return false;
424  }
425 
426  return true;
427 }
428 
429 bool
430 EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD,
431  CharUnits Offset) const {
432  // We don't have to keep looking past the maximum offset that's known to
433  // contain an empty class.
434  if (!AnyEmptySubobjectsBeyondOffset(Offset))
435  return true;
436 
437  QualType T = FD->getType();
438  if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
439  return CanPlaceFieldSubobjectAtOffset(RD, RD, Offset);
440 
441  // If we have an array type we need to look at every element.
442  if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
443  QualType ElemTy = Context.getBaseElementType(AT);
444  const RecordType *RT = ElemTy->getAs<RecordType>();
445  if (!RT)
446  return true;
447 
448  const CXXRecordDecl *RD = RT->getAsCXXRecordDecl();
449  const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
450 
451  uint64_t NumElements = Context.getConstantArrayElementCount(AT);
452  CharUnits ElementOffset = Offset;
453  for (uint64_t I = 0; I != NumElements; ++I) {
454  // We don't have to keep looking past the maximum offset that's known to
455  // contain an empty class.
456  if (!AnyEmptySubobjectsBeyondOffset(ElementOffset))
457  return true;
458 
459  if (!CanPlaceFieldSubobjectAtOffset(RD, RD, ElementOffset))
460  return false;
461 
462  ElementOffset += Layout.getSize();
463  }
464  }
465 
466  return true;
467 }
468 
469 bool
470 EmptySubobjectMap::CanPlaceFieldAtOffset(const FieldDecl *FD,
471  CharUnits Offset) {
472  if (!CanPlaceFieldSubobjectAtOffset(FD, Offset))
473  return false;
474 
475  // We are able to place the member variable at this offset.
476  // Make sure to update the empty field subobject map.
477  UpdateEmptyFieldSubobjects(FD, Offset, FD->hasAttr<NoUniqueAddressAttr>());
478  return true;
479 }
480 
481 void EmptySubobjectMap::UpdateEmptyFieldSubobjects(
482  const CXXRecordDecl *RD, const CXXRecordDecl *Class, CharUnits Offset,
483  bool PlacingOverlappingField) {
484  // We know that the only empty subobjects that can conflict with empty
485  // field subobjects are subobjects of empty bases and potentially-overlapping
486  // fields that can be placed at offset zero. Because of this, we only need to
487  // keep track of empty field subobjects with offsets less than the size of
488  // the largest empty subobject for our class.
489  //
490  // (Proof: we will only consider placing a subobject at offset zero or at
491  // >= the current dsize. The only cases where the earlier subobject can be
492  // placed beyond the end of dsize is if it's an empty base or a
493  // potentially-overlapping field.)
494  if (!PlacingOverlappingField && Offset >= SizeOfLargestEmptySubobject)
495  return;
496 
497  AddSubobjectAtOffset(RD, Offset);
498 
499  const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
500 
501  // Traverse all non-virtual bases.
502  for (const CXXBaseSpecifier &Base : RD->bases()) {
503  if (Base.isVirtual())
504  continue;
505 
506  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
507 
508  CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(BaseDecl);
509  UpdateEmptyFieldSubobjects(BaseDecl, Class, BaseOffset,
510  PlacingOverlappingField);
511  }
512 
513  if (RD == Class) {
514  // This is the most derived class, traverse virtual bases as well.
515  for (const CXXBaseSpecifier &Base : RD->vbases()) {
516  const CXXRecordDecl *VBaseDecl = Base.getType()->getAsCXXRecordDecl();
517 
518  CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBaseDecl);
519  UpdateEmptyFieldSubobjects(VBaseDecl, Class, VBaseOffset,
520  PlacingOverlappingField);
521  }
522  }
523 
524  // Traverse all member variables.
525  unsigned FieldNo = 0;
526  for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
527  I != E; ++I, ++FieldNo) {
528  if (I->isBitField())
529  continue;
530 
531  CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
532 
533  UpdateEmptyFieldSubobjects(*I, FieldOffset, PlacingOverlappingField);
534  }
535 }
536 
537 void EmptySubobjectMap::UpdateEmptyFieldSubobjects(
538  const FieldDecl *FD, CharUnits Offset, bool PlacingOverlappingField) {
539  QualType T = FD->getType();
540  if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl()) {
541  UpdateEmptyFieldSubobjects(RD, RD, Offset, PlacingOverlappingField);
542  return;
543  }
544 
545  // If we have an array type we need to update every element.
546  if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
547  QualType ElemTy = Context.getBaseElementType(AT);
548  const RecordType *RT = ElemTy->getAs<RecordType>();
549  if (!RT)
550  return;
551 
552  const CXXRecordDecl *RD = RT->getAsCXXRecordDecl();
553  const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
554 
555  uint64_t NumElements = Context.getConstantArrayElementCount(AT);
556  CharUnits ElementOffset = Offset;
557 
558  for (uint64_t I = 0; I != NumElements; ++I) {
559  // We know that the only empty subobjects that can conflict with empty
560  // field subobjects are subobjects of empty bases that can be placed at
561  // offset zero. Because of this, we only need to keep track of empty field
562  // subobjects with offsets less than the size of the largest empty
563  // subobject for our class.
564  if (!PlacingOverlappingField &&
565  ElementOffset >= SizeOfLargestEmptySubobject)
566  return;
567 
568  UpdateEmptyFieldSubobjects(RD, RD, ElementOffset,
569  PlacingOverlappingField);
570  ElementOffset += Layout.getSize();
571  }
572  }
573 }
574 
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.
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.
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  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  TargetCXXABI getCXXABI() const {
721  return Context.getTargetInfo().getCXXABI();
722  }
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  void UpdateAlignment(CharUnits NewAlignment, CharUnits UnpackedNewAlignment) {
786  UpdateAlignment(NewAlignment, UnpackedNewAlignment, NewAlignment);
787  }
788  void UpdateAlignment(CharUnits NewAlignment) {
789  UpdateAlignment(NewAlignment, NewAlignment, NewAlignment);
790  }
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  CharUnits getSize() const {
807  assert(Size % Context.getCharWidth() == 0);
808  return Context.toCharUnitsFromBits(Size);
809  }
810  uint64_t getSizeInBits() const { return Size; }
811 
812  void setSize(CharUnits NewSize) { Size = Context.toBits(NewSize); }
813  void setSize(uint64_t NewSize) { Size = NewSize; }
814 
815  CharUnits getAligment() const { return Alignment; }
816 
817  CharUnits getDataSize() const {
818  assert(DataSize % Context.getCharWidth() == 0);
819  return Context.toCharUnitsFromBits(DataSize);
820  }
821  uint64_t getDataSizeInBits() const { return DataSize; }
822 
823  void setDataSize(CharUnits NewSize) { DataSize = Context.toBits(NewSize); }
824  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 void ItaniumRecordLayoutBuilder::SelectPrimaryVBase(const CXXRecordDecl *RD) {
832  for (const auto &I : RD->bases()) {
833  assert(!I.getType()->isDependentType() &&
834  "Cannot layout class with dependent bases.");
835 
836  const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
837 
838  // Check if this is a nearly empty virtual base.
839  if (I.isVirtual() && Context.isNearlyEmpty(Base)) {
840  // If it's not an indirect primary base, then we've found our primary
841  // base.
842  if (!IndirectPrimaryBases.count(Base)) {
843  PrimaryBase = Base;
844  PrimaryBaseIsVirtual = true;
845  return;
846  }
847 
848  // Is this the first nearly empty virtual base?
849  if (!FirstNearlyEmptyVBase)
850  FirstNearlyEmptyVBase = Base;
851  }
852 
853  SelectPrimaryVBase(Base);
854  if (PrimaryBase)
855  return;
856  }
857 }
858 
859 /// DeterminePrimaryBase - Determine the primary base of the given class.
860 void ItaniumRecordLayoutBuilder::DeterminePrimaryBase(const CXXRecordDecl *RD) {
861  // If the class isn't dynamic, it won't have a primary base.
862  if (!RD->isDynamicClass())
863  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  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  for (const auto &I : RD->bases()) {
873  // Ignore virtual bases.
874  if (I.isVirtual())
875  continue;
876 
877  const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
878 
879  if (Base->isDynamicClass()) {
880  // We found it.
881  PrimaryBase = Base;
882  PrimaryBaseIsVirtual = false;
883  return;
884  }
885  }
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  if (RD->getNumVBases() != 0) {
892  SelectPrimaryVBase(RD);
893  if (PrimaryBase)
894  return;
895  }
896 
897  // Otherwise, it is the first indirect primary base class, if one exists.
898  if (FirstNearlyEmptyVBase) {
899  PrimaryBase = FirstNearlyEmptyVBase;
900  PrimaryBaseIsVirtual = true;
901  return;
902  }
903 
904  assert(!PrimaryBase && "Should not get here with a primary base!");
905 }
906 
907 BaseSubobjectInfo *ItaniumRecordLayoutBuilder::ComputeBaseSubobjectInfo(
908  const CXXRecordDecl *RD, bool IsVirtual, BaseSubobjectInfo *Derived) {
909  BaseSubobjectInfo *Info;
910 
911  if (IsVirtual) {
912  // Check if we already have info about this virtual base.
913  BaseSubobjectInfo *&InfoSlot = VirtualBaseInfo[RD];
914  if (InfoSlot) {
915  assert(InfoSlot->Class == RD && "Wrong class for virtual base info!");
916  return InfoSlot;
917  }
918 
919  // We don't, create it.
920  InfoSlot = new (BaseSubobjectInfoAllocator.Allocate()) BaseSubobjectInfo;
921  Info = InfoSlot;
922  } else {
923  Info = new (BaseSubobjectInfoAllocator.Allocate()) BaseSubobjectInfo;
924  }
925 
926  Info->Class = RD;
927  Info->IsVirtual = IsVirtual;
928  Info->Derived = nullptr;
929  Info->PrimaryVirtualBaseInfo = nullptr;
930 
931  const CXXRecordDecl *PrimaryVirtualBase = nullptr;
932  BaseSubobjectInfo *PrimaryVirtualBaseInfo = nullptr;
933 
934  // Check if this base has a primary virtual base.
935  if (RD->getNumVBases()) {
936  const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
937  if (Layout.isPrimaryBaseVirtual()) {
938  // This base does have a primary virtual base.
939  PrimaryVirtualBase = Layout.getPrimaryBase();
940  assert(PrimaryVirtualBase && "Didn't have a primary virtual base!");
941 
942  // Now check if we have base subobject info about this primary base.
943  PrimaryVirtualBaseInfo = VirtualBaseInfo.lookup(PrimaryVirtualBase);
944 
945  if (PrimaryVirtualBaseInfo) {
946  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  PrimaryVirtualBase = nullptr;
951  } else {
952  // We can claim this base as our primary base.
953  Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
954  PrimaryVirtualBaseInfo->Derived = Info;
955  }
956  }
957  }
958  }
959 
960  // Now go through all direct bases.
961  for (const auto &I : RD->bases()) {
962  bool IsVirtual = I.isVirtual();
963 
964  const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
965 
966  Info->Bases.push_back(ComputeBaseSubobjectInfo(BaseDecl, IsVirtual, Info));
967  }
968 
969  if (PrimaryVirtualBase && !PrimaryVirtualBaseInfo) {
970  // Traversing the bases must have created the base info for our primary
971  // virtual base.
972  PrimaryVirtualBaseInfo = VirtualBaseInfo.lookup(PrimaryVirtualBase);
973  assert(PrimaryVirtualBaseInfo &&
974  "Did not create a primary virtual base!");
975 
976  // Claim the primary virtual base as our primary virtual base.
977  Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
978  PrimaryVirtualBaseInfo->Derived = Info;
979  }
980 
981  return Info;
982 }
983 
984 void ItaniumRecordLayoutBuilder::ComputeBaseSubobjectInfo(
985  const CXXRecordDecl *RD) {
986  for (const auto &I : RD->bases()) {
987  bool IsVirtual = I.isVirtual();
988 
989  const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
990 
991  // Compute the base subobject info for this base.
992  BaseSubobjectInfo *Info = ComputeBaseSubobjectInfo(BaseDecl, IsVirtual,
993  nullptr);
994 
995  if (IsVirtual) {
996  // ComputeBaseInfo has already added this base for us.
997  assert(VirtualBaseInfo.count(BaseDecl) &&
998  "Did not add virtual base!");
999  } else {
1000  // Add the base info to the map of non-virtual bases.
1001  assert(!NonVirtualBaseInfo.count(BaseDecl) &&
1002  "Non-virtual base already exists!");
1003  NonVirtualBaseInfo.insert(std::make_pair(BaseDecl, Info));
1004  }
1005  }
1006 }
1007 
1008 void ItaniumRecordLayoutBuilder::EnsureVTablePointerAlignment(
1009  CharUnits UnpackedBaseAlign) {
1010  CharUnits BaseAlign = Packed ? CharUnits::One() : UnpackedBaseAlign;
1011 
1012  // The maximum field alignment overrides base align.
1013  if (!MaxFieldAlignment.isZero()) {
1014  BaseAlign = std::min(BaseAlign, MaxFieldAlignment);
1015  UnpackedBaseAlign = std::min(UnpackedBaseAlign, MaxFieldAlignment);
1016  }
1017 
1018  // Round up the current record size to pointer alignment.
1019  setSize(getSize().alignTo(BaseAlign));
1020 
1021  // Update the alignment.
1022  UpdateAlignment(BaseAlign, UnpackedBaseAlign, BaseAlign);
1023 }
1024 
1025 void ItaniumRecordLayoutBuilder::LayoutNonVirtualBases(
1026  const CXXRecordDecl *RD) {
1027  // Then, determine the primary base class.
1028  DeterminePrimaryBase(RD);
1029 
1030  // Compute base subobject info.
1031  ComputeBaseSubobjectInfo(RD);
1032 
1033  // If we have a primary base class, lay it out.
1034  if (PrimaryBase) {
1035  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  BaseSubobjectInfo *PrimaryBaseInfo = VirtualBaseInfo.lookup(PrimaryBase);
1039  PrimaryBaseInfo->Derived = nullptr;
1040 
1041  // We have a virtual primary base, insert it as an indirect primary base.
1042  IndirectPrimaryBases.insert(PrimaryBase);
1043 
1044  assert(!VisitedVirtualBases.count(PrimaryBase) &&
1045  "vbase already visited!");
1046  VisitedVirtualBases.insert(PrimaryBase);
1047 
1048  LayoutVirtualBase(PrimaryBaseInfo);
1049  } else {
1050  BaseSubobjectInfo *PrimaryBaseInfo =
1051  NonVirtualBaseInfo.lookup(PrimaryBase);
1052  assert(PrimaryBaseInfo &&
1053  "Did not find base info for non-virtual primary base!");
1054 
1055  LayoutNonVirtualBase(PrimaryBaseInfo);
1056  }
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  } else if (RD->isDynamicClass()) {
1061  assert(DataSize == 0 && "Vtable pointer must be at offset zero!");
1062  CharUnits PtrWidth =
1063  Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
1064  CharUnits PtrAlign =
1065  Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(0));
1066  EnsureVTablePointerAlignment(PtrAlign);
1067  HasOwnVFPtr = true;
1068 
1069  assert(!IsUnion && "Unions cannot be dynamic classes.");
1070  HandledFirstNonOverlappingEmptyField = true;
1071 
1072  setSize(getSize() + PtrWidth);
1073  setDataSize(getSize());
1074  }
1075 
1076  // Now lay out the non-virtual bases.
1077  for (const auto &I : RD->bases()) {
1078 
1079  // Ignore virtual bases.
1080  if (I.isVirtual())
1081  continue;
1082 
1083  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  if (BaseDecl == PrimaryBase && !PrimaryBaseIsVirtual)
1089  continue;
1090 
1091  // Lay out the base.
1092  BaseSubobjectInfo *BaseInfo = NonVirtualBaseInfo.lookup(BaseDecl);
1093  assert(BaseInfo && "Did not find base info for non-virtual base!");
1094 
1095  LayoutNonVirtualBase(BaseInfo);
1096  }
1097 }
1098 
1099 void ItaniumRecordLayoutBuilder::LayoutNonVirtualBase(
1100  const BaseSubobjectInfo *Base) {
1101  // Layout the base.
1102  CharUnits Offset = LayoutBase(Base);
1103 
1104  // Add its base class offset.
1105  assert(!Bases.count(Base->Class) && "base offset already exists!");
1106  Bases.insert(std::make_pair(Base->Class, Offset));
1107 
1108  AddPrimaryVirtualBaseOffsets(Base, Offset);
1109 }
1110 
1111 void ItaniumRecordLayoutBuilder::AddPrimaryVirtualBaseOffsets(
1112  const BaseSubobjectInfo *Info, CharUnits Offset) {
1113  // This base isn't interesting, it has no virtual bases.
1114  if (!Info->Class->getNumVBases())
1115  return;
1116 
1117  // First, check if we have a virtual primary base to add offsets for.
1118  if (Info->PrimaryVirtualBaseInfo) {
1119  assert(Info->PrimaryVirtualBaseInfo->IsVirtual &&
1120  "Primary virtual base is not virtual!");
1121  if (Info->PrimaryVirtualBaseInfo->Derived == Info) {
1122  // Add the offset.
1123  assert(!VBases.count(Info->PrimaryVirtualBaseInfo->Class) &&
1124  "primary vbase offset already exists!");
1125  VBases.insert(std::make_pair(Info->PrimaryVirtualBaseInfo->Class,
1127 
1128  // Traverse the primary virtual base.
1129  AddPrimaryVirtualBaseOffsets(Info->PrimaryVirtualBaseInfo, Offset);
1130  }
1131  }
1132 
1133  // Now go through all direct non-virtual bases.
1134  const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
1135  for (const BaseSubobjectInfo *Base : Info->Bases) {
1136  if (Base->IsVirtual)
1137  continue;
1138 
1139  CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
1140  AddPrimaryVirtualBaseOffsets(Base, BaseOffset);
1141  }
1142 }
1143 
1144 void ItaniumRecordLayoutBuilder::LayoutVirtualBases(
1145  const CXXRecordDecl *RD, const CXXRecordDecl *MostDerivedClass) {
1146  const CXXRecordDecl *PrimaryBase;
1147  bool PrimaryBaseIsVirtual;
1148 
1149  if (MostDerivedClass == RD) {
1150  PrimaryBase = this->PrimaryBase;
1151  PrimaryBaseIsVirtual = this->PrimaryBaseIsVirtual;
1152  } else {
1153  const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1154  PrimaryBase = Layout.getPrimaryBase();
1155  PrimaryBaseIsVirtual = Layout.isPrimaryBaseVirtual();
1156  }
1157 
1158  for (const CXXBaseSpecifier &Base : RD->bases()) {
1159  assert(!Base.getType()->isDependentType() &&
1160  "Cannot layout class with dependent bases.");
1161 
1162  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1163 
1164  if (Base.isVirtual()) {
1165  if (PrimaryBase != BaseDecl || !PrimaryBaseIsVirtual) {
1166  bool IndirectPrimaryBase = IndirectPrimaryBases.count(BaseDecl);
1167 
1168  // Only lay out the virtual base if it's not an indirect primary base.
1169  if (!IndirectPrimaryBase) {
1170  // Only visit virtual bases once.
1171  if (!VisitedVirtualBases.insert(BaseDecl).second)
1172  continue;
1173 
1174  const BaseSubobjectInfo *BaseInfo = VirtualBaseInfo.lookup(BaseDecl);
1175  assert(BaseInfo && "Did not find virtual base info!");
1176  LayoutVirtualBase(BaseInfo);
1177  }
1178  }
1179  }
1180 
1181  if (!BaseDecl->getNumVBases()) {
1182  // This base isn't interesting since it doesn't have any virtual bases.
1183  continue;
1184  }
1185 
1186  LayoutVirtualBases(BaseDecl, MostDerivedClass);
1187  }
1188 }
1189 
1190 void ItaniumRecordLayoutBuilder::LayoutVirtualBase(
1191  const BaseSubobjectInfo *Base) {
1192  assert(!Base->Derived && "Trying to lay out a primary virtual base!");
1193 
1194  // Layout the base.
1195  CharUnits Offset = LayoutBase(Base);
1196 
1197  // Add its base class offset.
1198  assert(!VBases.count(Base->Class) && "vbase offset already exists!");
1199  VBases.insert(std::make_pair(Base->Class,
1201 
1202  AddPrimaryVirtualBaseOffsets(Base, Offset);
1203 }
1204 
1205 CharUnits
1206 ItaniumRecordLayoutBuilder::LayoutBase(const BaseSubobjectInfo *Base) {
1207  assert(!IsUnion && "Unions cannot have base classes.");
1208 
1209  const ASTRecordLayout &Layout = Context.getASTRecordLayout(Base->Class);
1210  CharUnits Offset;
1211 
1212  // Query the external layout to see if it provides an offset.
1213  bool HasExternalLayout = false;
1214  if (UseExternalLayout) {
1215  if (Base->IsVirtual)
1216  HasExternalLayout = External.getExternalVBaseOffset(Base->Class, Offset);
1217  else
1218  HasExternalLayout = External.getExternalNVBaseOffset(Base->Class, Offset);
1219  }
1220 
1221  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  return (Packed && ((Context.getLangOpts().getClangABICompat() <=
1226  Context.getTargetInfo().getTriple().isPS() ||
1227  Context.getTargetInfo().getTriple().isOSAIX()))
1228  ? CharUnits::One()
1229  : UnpackedAlign;
1230  };
1231 
1232  CharUnits UnpackedBaseAlign = Layout.getNonVirtualAlignment();
1233  CharUnits UnpackedPreferredBaseAlign = Layout.getPreferredNVAlignment();
1234  CharUnits BaseAlign =
1235  getBaseOrPreferredBaseAlignFromUnpacked(UnpackedBaseAlign);
1236  CharUnits PreferredBaseAlign =
1237  getBaseOrPreferredBaseAlignFromUnpacked(UnpackedPreferredBaseAlign);
1238 
1239  const bool DefaultsToAIXPowerAlignment =
1241  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  if (!Base->Class->isEmpty() && !HandledFirstNonOverlappingEmptyField) {
1247  // By handling a base class that is not empty, we're handling the
1248  // "first (inherited) member".
1249  HandledFirstNonOverlappingEmptyField = true;
1250  } else if (!IsNaturalAlign) {
1251  UnpackedPreferredBaseAlign = UnpackedBaseAlign;
1252  PreferredBaseAlign = BaseAlign;
1253  }
1254  }
1255 
1256  CharUnits UnpackedAlignTo = !DefaultsToAIXPowerAlignment
1257  ? UnpackedBaseAlign
1258  : UnpackedPreferredBaseAlign;
1259  // If we have an empty base class, try to place it at offset 0.
1260  if (Base->Class->isEmpty() &&
1261  (!HasExternalLayout || Offset == CharUnits::Zero()) &&
1262  EmptySubobjects->CanPlaceBaseAtOffset(Base, CharUnits::Zero())) {
1263  setSize(std::max(getSize(), Layout.getSize()));
1264  // On PS4/PS5, don't update the alignment, to preserve compatibility.
1265  if (!Context.getTargetInfo().getTriple().isPS())
1266  UpdateAlignment(BaseAlign, UnpackedAlignTo, PreferredBaseAlign);
1267 
1268  return CharUnits::Zero();
1269  }
1270 
1271  // The maximum field alignment overrides the base align/(AIX-only) preferred
1272  // base align.
1273  if (!MaxFieldAlignment.isZero()) {
1274  BaseAlign = std::min(BaseAlign, MaxFieldAlignment);
1275  PreferredBaseAlign = std::min(PreferredBaseAlign, MaxFieldAlignment);
1276  UnpackedAlignTo = std::min(UnpackedAlignTo, MaxFieldAlignment);
1277  }
1278 
1279  CharUnits AlignTo =
1280  !DefaultsToAIXPowerAlignment ? BaseAlign : PreferredBaseAlign;
1281  if (!HasExternalLayout) {
1282  // Round up the current record size to the base's alignment boundary.
1283  Offset = getDataSize().alignTo(AlignTo);
1284 
1285  // Try to place the base.
1286  while (!EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset))
1287  Offset += AlignTo;
1288  } else {
1289  bool Allowed = EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset);
1290  (void)Allowed;
1291  assert(Allowed && "Base subobject externally placed at overlapping offset");
1292 
1293  if (InferAlignment && Offset < getDataSize().alignTo(AlignTo)) {
1294  // The externally-supplied base offset is before the base offset we
1295  // computed. Assume that the structure is packed.
1296  Alignment = CharUnits::One();
1297  InferAlignment = false;
1298  }
1299  }
1300 
1301  if (!Base->Class->isEmpty()) {
1302  // Update the data size.
1303  setDataSize(Offset + Layout.getNonVirtualSize());
1304 
1305  setSize(std::max(getSize(), getDataSize()));
1306  } else
1307  setSize(std::max(getSize(), Offset + Layout.getSize()));
1308 
1309  // Remember max struct/class alignment.
1310  UpdateAlignment(BaseAlign, UnpackedAlignTo, PreferredBaseAlign);
1311 
1312  return Offset;
1313 }
1314 
1315 void ItaniumRecordLayoutBuilder::InitializeLayout(const Decl *D) {
1316  if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
1317  IsUnion = RD->isUnion();
1318  IsMsStruct = RD->isMsStruct(Context);
1319  }
1320 
1321  Packed = D->hasAttr<PackedAttr>();
1322 
1323  // Honor the default struct packing maximum alignment flag.
1324  if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct) {
1325  MaxFieldAlignment = CharUnits::fromQuantity(DefaultMaxFieldAlignment);
1326  }
1327 
1328  // mac68k alignment supersedes maximum field alignment and attribute aligned,
1329  // and forces all structures to have 2-byte alignment. The IBM docs on it
1330  // allude to additional (more complicated) semantics, especially with regard
1331  // to bit-fields, but gcc appears not to follow that.
1332  if (D->hasAttr<AlignMac68kAttr>()) {
1333  assert(
1334  !D->hasAttr<AlignNaturalAttr>() &&
1335  "Having both mac68k and natural alignment on a decl is not allowed.");
1336  IsMac68kAlign = true;
1337  MaxFieldAlignment = CharUnits::fromQuantity(2);
1338  Alignment = CharUnits::fromQuantity(2);
1339  PreferredAlignment = CharUnits::fromQuantity(2);
1340  } else {
1341  if (D->hasAttr<AlignNaturalAttr>())
1342  IsNaturalAlign = true;
1343 
1344  if (const MaxFieldAlignmentAttr *MFAA = D->getAttr<MaxFieldAlignmentAttr>())
1345  MaxFieldAlignment = Context.toCharUnitsFromBits(MFAA->getAlignment());
1346 
1347  if (unsigned MaxAlign = D->getMaxAlignment())
1348  UpdateAlignment(Context.toCharUnitsFromBits(MaxAlign));
1349  }
1350 
1351  HandledFirstNonOverlappingEmptyField =
1352  !Context.getTargetInfo().defaultsToAIXPowerAlignment() || IsNaturalAlign;
1353 
1354  // If there is an external AST source, ask it for the various offsets.
1355  if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
1356  if (ExternalASTSource *Source = Context.getExternalSource()) {
1357  UseExternalLayout = Source->layoutRecordType(
1358  RD, External.Size, External.Align, External.FieldOffsets,
1359  External.BaseOffsets, External.VirtualBaseOffsets);
1360 
1361  // Update based on external alignment.
1362  if (UseExternalLayout) {
1363  if (External.Align > 0) {
1364  Alignment = Context.toCharUnitsFromBits(External.Align);
1365  PreferredAlignment = Context.toCharUnitsFromBits(External.Align);
1366  } else {
1367  // The external source didn't have alignment information; infer it.
1368  InferAlignment = true;
1369  }
1370  }
1371  }
1372 }
1373 
1374 void ItaniumRecordLayoutBuilder::Layout(const RecordDecl *D) {
1375  InitializeLayout(D);
1376  LayoutFields(D);
1377 
1378  // Finally, round the size of the total struct up to the alignment of the
1379  // struct itself.
1380  FinishLayout(D);
1381 }
1382 
1383 void ItaniumRecordLayoutBuilder::Layout(const CXXRecordDecl *RD) {
1384  InitializeLayout(RD);
1385 
1386  // Lay out the vtable and the non-virtual bases.
1387  LayoutNonVirtualBases(RD);
1388 
1389  LayoutFields(RD);
1390 
1391  NonVirtualSize = Context.toCharUnitsFromBits(
1392  llvm::alignTo(getSizeInBits(), Context.getTargetInfo().getCharAlign()));
1393  NonVirtualAlignment = Alignment;
1394  PreferredNVAlignment = PreferredAlignment;
1395 
1396  // Lay out the virtual bases and add the primary virtual base offsets.
1397  LayoutVirtualBases(RD, RD);
1398 
1399  // Finally, round the size of the total struct up to the alignment
1400  // of the struct itself.
1401  FinishLayout(RD);
1402 
1403 #ifndef NDEBUG
1404  // Check that we have base offsets for all bases.
1405  for (const CXXBaseSpecifier &Base : RD->bases()) {
1406  if (Base.isVirtual())
1407  continue;
1408 
1409  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1410 
1411  assert(Bases.count(BaseDecl) && "Did not find base offset!");
1412  }
1413 
1414  // And all virtual bases.
1415  for (const CXXBaseSpecifier &Base : RD->vbases()) {
1416  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1417 
1418  assert(VBases.count(BaseDecl) && "Did not find base offset!");
1419  }
1420 #endif
1421 }
1422 
1423 void ItaniumRecordLayoutBuilder::Layout(const ObjCInterfaceDecl *D) {
1424  if (ObjCInterfaceDecl *SD = D->getSuperClass()) {
1425  const ASTRecordLayout &SL = Context.getASTObjCInterfaceLayout(SD);
1426 
1427  UpdateAlignment(SL.getAlignment());
1428 
1429  // We start laying out ivars not at the end of the superclass
1430  // structure, but at the next byte following the last field.
1431  setDataSize(SL.getDataSize());
1432  setSize(getDataSize());
1433  }
1434 
1435  InitializeLayout(D);
1436  // Layout each ivar sequentially.
1437  for (const ObjCIvarDecl *IVD = D->all_declared_ivar_begin(); IVD;
1438  IVD = IVD->getNextIvar())
1439  LayoutField(IVD, false);
1440 
1441  // Finally, round the size of the total struct up to the alignment of the
1442  // struct itself.
1443  FinishLayout(D);
1444 }
1445 
1446 void ItaniumRecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
1447  // Layout each field, for now, just sequentially, respecting alignment. In
1448  // the future, this will need to be tweakable by targets.
1449  bool InsertExtraPadding = D->mayInsertExtraPadding(/*EmitRemark=*/true);
1450  bool HasFlexibleArrayMember = D->hasFlexibleArrayMember();
1451  for (auto I = D->field_begin(), End = D->field_end(); I != End; ++I) {
1452  auto Next(I);
1453  ++Next;
1454  LayoutField(*I,
1455  InsertExtraPadding && (Next != End || !HasFlexibleArrayMember));
1456  }
1457 }
1458 
1459 // Rounds the specified size to have it a multiple of the char size.
1460 static uint64_t
1462  const ASTContext &Context) {
1463  uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
1464  return llvm::alignTo(Size, CharAlignment);
1465 }
1466 
1467 void ItaniumRecordLayoutBuilder::LayoutWideBitField(uint64_t FieldSize,
1468  uint64_t StorageUnitSize,
1469  bool FieldPacked,
1470  const FieldDecl *D) {
1471  assert(Context.getLangOpts().CPlusPlus &&
1472  "Can only have wide bit-fields in C++!");
1473 
1474  // Itanium C++ ABI 2.4:
1475  // If sizeof(T)*8 < n, let T' be the largest integral POD type with
1476  // sizeof(T')*8 <= n.
1477 
1478  QualType IntegralPODTypes[] = {
1479  Context.UnsignedCharTy, Context.UnsignedShortTy, Context.UnsignedIntTy,
1480  Context.UnsignedLongTy, Context.UnsignedLongLongTy
1481  };
1482 
1483  QualType Type;
1484  for (const QualType &QT : IntegralPODTypes) {
1485  uint64_t Size = Context.getTypeSize(QT);
1486 
1487  if (Size > FieldSize)
1488  break;
1489 
1490  Type = QT;
1491  }
1492  assert(!Type.isNull() && "Did not find a type!");
1493 
1494  CharUnits TypeAlign = Context.getTypeAlignInChars(Type);
1495 
1496  // We're not going to use any of the unfilled bits in the last byte.
1497  UnfilledBitsInLastUnit = 0;
1498  LastBitfieldStorageUnitSize = 0;
1499 
1500  uint64_t FieldOffset;
1501  uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;
1502 
1503  if (IsUnion) {
1504  uint64_t RoundedFieldSize = roundUpSizeToCharAlignment(FieldSize,
1505  Context);
1506  setDataSize(std::max(getDataSizeInBits(), RoundedFieldSize));
1507  FieldOffset = 0;
1508  } else {
1509  // The bitfield is allocated starting at the next offset aligned
1510  // appropriately for T', with length n bits.
1511  FieldOffset = llvm::alignTo(getDataSizeInBits(), Context.toBits(TypeAlign));
1512 
1513  uint64_t NewSizeInBits = FieldOffset + FieldSize;
1514 
1515  setDataSize(
1516  llvm::alignTo(NewSizeInBits, Context.getTargetInfo().getCharAlign()));
1517  UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;
1518  }
1519 
1520  // Place this field at the current location.
1521  FieldOffsets.push_back(FieldOffset);
1522 
1523  CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, FieldOffset,
1524  Context.toBits(TypeAlign), FieldPacked, D);
1525 
1526  // Update the size.
1527  setSize(std::max(getSizeInBits(), getDataSizeInBits()));
1528 
1529  // Remember max struct/class alignment.
1530  UpdateAlignment(TypeAlign);
1531 }
1532 
1533 static bool isAIXLayout(const ASTContext &Context) {
1534  return Context.getTargetInfo().getTriple().getOS() == llvm::Triple::AIX;
1535 }
1536 
1537 void ItaniumRecordLayoutBuilder::LayoutBitField(const FieldDecl *D) {
1538  bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
1539  uint64_t FieldSize = D->getBitWidthValue(Context);
1540  TypeInfo FieldInfo = Context.getTypeInfo(D->getType());
1541  uint64_t StorageUnitSize = FieldInfo.Width;
1542  unsigned FieldAlign = FieldInfo.Align;
1543  bool AlignIsRequired = FieldInfo.isAlignRequired();
1544 
1545  // UnfilledBitsInLastUnit is the difference between the end of the
1546  // last allocated bitfield (i.e. the first bit offset available for
1547  // bitfields) and the end of the current data size in bits (i.e. the
1548  // first bit offset available for non-bitfields). The current data
1549  // size in bits is always a multiple of the char size; additionally,
1550  // for ms_struct records it's also a multiple of the
1551  // LastBitfieldStorageUnitSize (if set).
1552 
1553  // The struct-layout algorithm is dictated by the platform ABI,
1554  // which in principle could use almost any rules it likes. In
1555  // practice, UNIXy targets tend to inherit the algorithm described
1556  // in the System V generic ABI. The basic bitfield layout rule in
1557  // System V is to place bitfields at the next available bit offset
1558  // where the entire bitfield would fit in an aligned storage unit of
1559  // the declared type; it's okay if an earlier or later non-bitfield
1560  // is allocated in the same storage unit. However, some targets
1561  // (those that !useBitFieldTypeAlignment(), e.g. ARM APCS) don't
1562  // require this storage unit to be aligned, and therefore always put
1563  // the bitfield at the next available bit offset.
1564 
1565  // ms_struct basically requests a complete replacement of the
1566  // platform ABI's struct-layout algorithm, with the high-level goal
1567  // of duplicating MSVC's layout. For non-bitfields, this follows
1568  // the standard algorithm. The basic bitfield layout rule is to
1569  // allocate an entire unit of the bitfield's declared type
1570  // (e.g. 'unsigned long'), then parcel it up among successive
1571  // bitfields whose declared types have the same size, making a new
1572  // unit as soon as the last can no longer store the whole value.
1573  // Since it completely replaces the platform ABI's algorithm,
1574  // settings like !useBitFieldTypeAlignment() do not apply.
1575 
1576  // A zero-width bitfield forces the use of a new storage unit for
1577  // later bitfields. In general, this occurs by rounding up the
1578  // current size of the struct as if the algorithm were about to
1579  // place a non-bitfield of the field's formal type. Usually this
1580  // does not change the alignment of the struct itself, but it does
1581  // on some targets (those that useZeroLengthBitfieldAlignment(),
1582  // e.g. ARM). In ms_struct layout, zero-width bitfields are
1583  // ignored unless they follow a non-zero-width bitfield.
1584 
1585  // A field alignment restriction (e.g. from #pragma pack) or
1586  // specification (e.g. from __attribute__((aligned))) changes the
1587  // formal alignment of the field. For System V, this alters the
1588  // required alignment of the notional storage unit that must contain
1589  // the bitfield. For ms_struct, this only affects the placement of
1590  // new storage units. In both cases, the effect of #pragma pack is
1591  // ignored on zero-width bitfields.
1592 
1593  // On System V, a packed field (e.g. from #pragma pack or
1594  // __attribute__((packed))) always uses the next available bit
1595  // offset.
1596 
1597  // In an ms_struct struct, the alignment of a fundamental type is
1598  // always equal to its size. This is necessary in order to mimic
1599  // the i386 alignment rules on targets which might not fully align
1600  // all types (e.g. Darwin PPC32, where alignof(long long) == 4).
1601 
1602  // First, some simple bookkeeping to perform for ms_struct structs.
1603  if (IsMsStruct) {
1604  // The field alignment for integer types is always the size.
1605  FieldAlign = StorageUnitSize;
1606 
1607  // If the previous field was not a bitfield, or was a bitfield
1608  // with a different storage unit size, or if this field doesn't fit into
1609  // the current storage unit, we're done with that storage unit.
1610  if (LastBitfieldStorageUnitSize != StorageUnitSize ||
1611  UnfilledBitsInLastUnit < FieldSize) {
1612  // Also, ignore zero-length bitfields after non-bitfields.
1613  if (!LastBitfieldStorageUnitSize && !FieldSize)
1614  FieldAlign = 1;
1615 
1616  UnfilledBitsInLastUnit = 0;
1617  LastBitfieldStorageUnitSize = 0;
1618  }
1619  }
1620 
1621  if (isAIXLayout(Context)) {
1622  if (StorageUnitSize < Context.getTypeSize(Context.UnsignedIntTy)) {
1623  // On AIX, [bool, char, short] bitfields have the same alignment
1624  // as [unsigned].
1625  StorageUnitSize = Context.getTypeSize(Context.UnsignedIntTy);
1626  } else if (StorageUnitSize > Context.getTypeSize(Context.UnsignedIntTy) &&
1627  Context.getTargetInfo().getTriple().isArch32Bit() &&
1628  FieldSize <= 32) {
1629  // Under 32-bit compile mode, the bitcontainer is 32 bits if a single
1630  // long long bitfield has length no greater than 32 bits.
1631  StorageUnitSize = 32;
1632 
1633  if (!AlignIsRequired)
1634  FieldAlign = 32;
1635  }
1636 
1637  if (FieldAlign < StorageUnitSize) {
1638  // The bitfield alignment should always be greater than or equal to
1639  // bitcontainer size.
1640  FieldAlign = StorageUnitSize;
1641  }
1642  }
1643 
1644  // If the field is wider than its declared type, it follows
1645  // different rules in all cases, except on AIX.
1646  // On AIX, wide bitfield follows the same rules as normal bitfield.
1647  if (FieldSize > StorageUnitSize && !isAIXLayout(Context)) {
1648  LayoutWideBitField(FieldSize, StorageUnitSize, FieldPacked, D);
1649  return;
1650  }
1651 
1652  // Compute the next available bit offset.
1653  uint64_t FieldOffset =
1654  IsUnion ? 0 : (getDataSizeInBits() - UnfilledBitsInLastUnit);
1655 
1656  // Handle targets that don't honor bitfield type alignment.
1657  if (!IsMsStruct && !Context.getTargetInfo().useBitFieldTypeAlignment()) {
1658  // Some such targets do honor it on zero-width bitfields.
1659  if (FieldSize == 0 &&
1661  // Some targets don't honor leading zero-width bitfield.
1662  if (!IsUnion && FieldOffset == 0 &&
1664  FieldAlign = 1;
1665  else {
1666  // The alignment to round up to is the max of the field's natural
1667  // alignment and a target-specific fixed value (sometimes zero).
1668  unsigned ZeroLengthBitfieldBoundary =
1670  FieldAlign = std::max(FieldAlign, ZeroLengthBitfieldBoundary);
1671  }
1672  // If that doesn't apply, just ignore the field alignment.
1673  } else {
1674  FieldAlign = 1;
1675  }
1676  }
1677 
1678  // Remember the alignment we would have used if the field were not packed.
1679  unsigned UnpackedFieldAlign = FieldAlign;
1680 
1681  // Ignore the field alignment if the field is packed unless it has zero-size.
1682  if (!IsMsStruct && FieldPacked && FieldSize != 0)
1683  FieldAlign = 1;
1684 
1685  // But, if there's an 'aligned' attribute on the field, honor that.
1686  unsigned ExplicitFieldAlign = D->getMaxAlignment();
1687  if (ExplicitFieldAlign) {
1688  FieldAlign = std::max(FieldAlign, ExplicitFieldAlign);
1689  UnpackedFieldAlign = std::max(UnpackedFieldAlign, ExplicitFieldAlign);
1690  }
1691 
1692  // But, if there's a #pragma pack in play, that takes precedent over
1693  // even the 'aligned' attribute, for non-zero-width bitfields.
1694  unsigned MaxFieldAlignmentInBits = Context.toBits(MaxFieldAlignment);
1695  if (!MaxFieldAlignment.isZero() && FieldSize) {
1696  UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignmentInBits);
1697  if (FieldPacked)
1698  FieldAlign = UnpackedFieldAlign;
1699  else
1700  FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
1701  }
1702 
1703  // But, ms_struct just ignores all of that in unions, even explicit
1704  // alignment attributes.
1705  if (IsMsStruct && IsUnion) {
1706  FieldAlign = UnpackedFieldAlign = 1;
1707  }
1708 
1709  // For purposes of diagnostics, we're going to simultaneously
1710  // compute the field offsets that we would have used if we weren't
1711  // adding any alignment padding or if the field weren't packed.
1712  uint64_t UnpaddedFieldOffset = FieldOffset;
1713  uint64_t UnpackedFieldOffset = FieldOffset;
1714 
1715  // Check if we need to add padding to fit the bitfield within an
1716  // allocation unit with the right size and alignment. The rules are
1717  // somewhat different here for ms_struct structs.
1718  if (IsMsStruct) {
1719  // If it's not a zero-width bitfield, and we can fit the bitfield
1720  // into the active storage unit (and we haven't already decided to
1721  // start a new storage unit), just do so, regardless of any other
1722  // other consideration. Otherwise, round up to the right alignment.
1723  if (FieldSize == 0 || FieldSize > UnfilledBitsInLastUnit) {
1724  FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
1725  UnpackedFieldOffset =
1726  llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
1727  UnfilledBitsInLastUnit = 0;
1728  }
1729 
1730  } else {
1731  // #pragma pack, with any value, suppresses the insertion of padding.
1732  bool AllowPadding = MaxFieldAlignment.isZero();
1733 
1734  // Compute the real offset.
1735  if (FieldSize == 0 ||
1736  (AllowPadding &&
1737  (FieldOffset & (FieldAlign - 1)) + FieldSize > StorageUnitSize)) {
1738  FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
1739  } else if (ExplicitFieldAlign &&
1740  (MaxFieldAlignmentInBits == 0 ||
1741  ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
1743  // TODO: figure it out what needs to be done on targets that don't honor
1744  // bit-field type alignment like ARM APCS ABI.
1745  FieldOffset = llvm::alignTo(FieldOffset, ExplicitFieldAlign);
1746  }
1747 
1748  // Repeat the computation for diagnostic purposes.
1749  if (FieldSize == 0 ||
1750  (AllowPadding &&
1751  (UnpackedFieldOffset & (UnpackedFieldAlign - 1)) + FieldSize >
1752  StorageUnitSize))
1753  UnpackedFieldOffset =
1754  llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
1755  else if (ExplicitFieldAlign &&
1756  (MaxFieldAlignmentInBits == 0 ||
1757  ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
1759  UnpackedFieldOffset =
1760  llvm::alignTo(UnpackedFieldOffset, ExplicitFieldAlign);
1761  }
1762 
1763  // If we're using external layout, give the external layout a chance
1764  // to override this information.
1765  if (UseExternalLayout)
1766  FieldOffset = updateExternalFieldOffset(D, FieldOffset);
1767 
1768  // Okay, place the bitfield at the calculated offset.
1769  FieldOffsets.push_back(FieldOffset);
1770 
1771  // Bookkeeping:
1772 
1773  // Anonymous members don't affect the overall record alignment,
1774  // except on targets where they do.
1775  if (!IsMsStruct &&
1777  !D->getIdentifier())
1778  FieldAlign = UnpackedFieldAlign = 1;
1779 
1780  // On AIX, zero-width bitfields pad out to the natural alignment boundary,
1781  // but do not increase the alignment greater than the MaxFieldAlignment, or 1
1782  // if packed.
1783  if (isAIXLayout(Context) && !FieldSize) {
1784  if (FieldPacked)
1785  FieldAlign = 1;
1786  if (!MaxFieldAlignment.isZero()) {
1787  UnpackedFieldAlign =
1788  std::min(UnpackedFieldAlign, MaxFieldAlignmentInBits);
1789  FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
1790  }
1791  }
1792 
1793  // Diagnose differences in layout due to padding or packing.
1794  if (!UseExternalLayout)
1795  CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, UnpackedFieldOffset,
1796  UnpackedFieldAlign, FieldPacked, D);
1797 
1798  // Update DataSize to include the last byte containing (part of) the bitfield.
1799 
1800  // For unions, this is just a max operation, as usual.
1801  if (IsUnion) {
1802  // For ms_struct, allocate the entire storage unit --- unless this
1803  // is a zero-width bitfield, in which case just use a size of 1.
1804  uint64_t RoundedFieldSize;
1805  if (IsMsStruct) {
1806  RoundedFieldSize = (FieldSize ? StorageUnitSize
1807  : Context.getTargetInfo().getCharWidth());
1808 
1809  // Otherwise, allocate just the number of bytes required to store
1810  // the bitfield.
1811  } else {
1812  RoundedFieldSize = roundUpSizeToCharAlignment(FieldSize, Context);
1813  }
1814  setDataSize(std::max(getDataSizeInBits(), RoundedFieldSize));
1815 
1816  // For non-zero-width bitfields in ms_struct structs, allocate a new
1817  // storage unit if necessary.
1818  } else if (IsMsStruct && FieldSize) {
1819  // We should have cleared UnfilledBitsInLastUnit in every case
1820  // where we changed storage units.
1821  if (!UnfilledBitsInLastUnit) {
1822  setDataSize(FieldOffset + StorageUnitSize);
1823  UnfilledBitsInLastUnit = StorageUnitSize;
1824  }
1825  UnfilledBitsInLastUnit -= FieldSize;
1826  LastBitfieldStorageUnitSize = StorageUnitSize;
1827 
1828  // Otherwise, bump the data size up to include the bitfield,
1829  // including padding up to char alignment, and then remember how
1830  // bits we didn't use.
1831  } else {
1832  uint64_t NewSizeInBits = FieldOffset + FieldSize;
1833  uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
1834  setDataSize(llvm::alignTo(NewSizeInBits, CharAlignment));
1835  UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;
1836 
1837  // The only time we can get here for an ms_struct is if this is a
1838  // zero-width bitfield, which doesn't count as anything for the
1839  // purposes of unfilled bits.
1840  LastBitfieldStorageUnitSize = 0;
1841  }
1842 
1843  // Update the size.
1844  setSize(std::max(getSizeInBits(), getDataSizeInBits()));
1845 
1846  // Remember max struct/class alignment.
1847  UnadjustedAlignment =
1848  std::max(UnadjustedAlignment, Context.toCharUnitsFromBits(FieldAlign));
1849  UpdateAlignment(Context.toCharUnitsFromBits(FieldAlign),
1850  Context.toCharUnitsFromBits(UnpackedFieldAlign));
1851 }
1852 
1853 void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D,
1854  bool InsertExtraPadding) {
1855  auto *FieldClass = D->getType()->getAsCXXRecordDecl();
1856  bool PotentiallyOverlapping = D->hasAttr<NoUniqueAddressAttr>() && FieldClass;
1857  bool IsOverlappingEmptyField =
1858  PotentiallyOverlapping && FieldClass->isEmpty();
1859 
1860  CharUnits FieldOffset =
1861  (IsUnion || IsOverlappingEmptyField) ? CharUnits::Zero() : getDataSize();
1862 
1863  const bool DefaultsToAIXPowerAlignment =
1865  bool FoundFirstNonOverlappingEmptyFieldForAIX = false;
1866  if (DefaultsToAIXPowerAlignment && !HandledFirstNonOverlappingEmptyField) {
1867  assert(FieldOffset == CharUnits::Zero() &&
1868  "The first non-overlapping empty field should have been handled.");
1869 
1870  if (!IsOverlappingEmptyField) {
1871  FoundFirstNonOverlappingEmptyFieldForAIX = true;
1872 
1873  // We're going to handle the "first member" based on
1874  // `FoundFirstNonOverlappingEmptyFieldForAIX` during the current
1875  // invocation of this function; record it as handled for future
1876  // invocations (except for unions, because the current field does not
1877  // represent all "firsts").
1878  HandledFirstNonOverlappingEmptyField = !IsUnion;
1879  }
1880  }
1881 
1882  if (D->isBitField()) {
1883  LayoutBitField(D);
1884  return;
1885  }
1886 
1887  uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;
1888  // Reset the unfilled bits.
1889  UnfilledBitsInLastUnit = 0;
1890  LastBitfieldStorageUnitSize = 0;
1891 
1892  llvm::Triple Target = Context.getTargetInfo().getTriple();
1893  bool FieldPacked = (Packed && (!FieldClass || FieldClass->isPOD() ||
1894  Context.getLangOpts().getClangABICompat() <=
1896  Target.isPS() || Target.isOSDarwin())) ||
1897  D->hasAttr<PackedAttr>();
1898 
1900  CharUnits FieldSize;
1901  CharUnits FieldAlign;
1902  // The amount of this class's dsize occupied by the field.
1903  // This is equal to FieldSize unless we're permitted to pack
1904  // into the field's tail padding.
1905  CharUnits EffectiveFieldSize;
1906 
1907  auto setDeclInfo = [&](bool IsIncompleteArrayType) {
1908  auto TI = Context.getTypeInfoInChars(D->getType());
1909  FieldAlign = TI.Align;
1910  // Flexible array members don't have any size, but they have to be
1911  // aligned appropriately for their element type.
1912  EffectiveFieldSize = FieldSize =
1913  IsIncompleteArrayType ? CharUnits::Zero() : TI.Width;
1914  AlignRequirement = TI.AlignRequirement;
1915  };
1916 
1917  if (D->getType()->isIncompleteArrayType()) {
1918  setDeclInfo(true /* IsIncompleteArrayType */);
1919  } else if (const ReferenceType *RT = D->getType()->getAs<ReferenceType>()) {
1920  unsigned AS = Context.getTargetAddressSpace(RT->getPointeeType());
1921  EffectiveFieldSize = FieldSize = Context.toCharUnitsFromBits(
1922  Context.getTargetInfo().getPointerWidth(AS));
1923  FieldAlign = Context.toCharUnitsFromBits(
1924  Context.getTargetInfo().getPointerAlign(AS));
1925  } else {
1926  setDeclInfo(false /* IsIncompleteArrayType */);
1927 
1928  // A potentially-overlapping field occupies its dsize or nvsize, whichever
1929  // is larger.
1930  if (PotentiallyOverlapping) {
1931  const ASTRecordLayout &Layout = Context.getASTRecordLayout(FieldClass);
1932  EffectiveFieldSize =
1933  std::max(Layout.getNonVirtualSize(), Layout.getDataSize());
1934  }
1935 
1936  if (IsMsStruct) {
1937  // If MS bitfield layout is required, figure out what type is being
1938  // laid out and align the field to the width of that type.
1939 
1940  // Resolve all typedefs down to their base type and round up the field
1941  // alignment if necessary.
1942  QualType T = Context.getBaseElementType(D->getType());
1943  if (const BuiltinType *BTy = T->getAs<BuiltinType>()) {
1944  CharUnits TypeSize = Context.getTypeSizeInChars(BTy);
1945 
1946  if (!llvm::isPowerOf2_64(TypeSize.getQuantity())) {
1947  assert(
1948  !Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() &&
1949  "Non PowerOf2 size in MSVC mode");
1950  // Base types with sizes that aren't a power of two don't work
1951  // with the layout rules for MS structs. This isn't an issue in
1952  // MSVC itself since there are no such base data types there.
1953  // On e.g. x86_32 mingw and linux, long double is 12 bytes though.
1954  // Any structs involving that data type obviously can't be ABI
1955  // compatible with MSVC regardless of how it is laid out.
1956 
1957  // Since ms_struct can be mass enabled (via a pragma or via the
1958  // -mms-bitfields command line parameter), this can trigger for
1959  // structs that don't actually need MSVC compatibility, so we
1960  // need to be able to sidestep the ms_struct layout for these types.
1961 
1962  // Since the combination of -mms-bitfields together with structs
1963  // like max_align_t (which contains a long double) for mingw is
1964  // quite common (and GCC handles it silently), just handle it
1965  // silently there. For other targets that have ms_struct enabled
1966  // (most probably via a pragma or attribute), trigger a diagnostic
1967  // that defaults to an error.
1968  if (!Context.getTargetInfo().getTriple().isWindowsGNUEnvironment())
1969  Diag(D->getLocation(), diag::warn_npot_ms_struct);
1970  }
1971  if (TypeSize > FieldAlign &&
1972  llvm::isPowerOf2_64(TypeSize.getQuantity()))
1973  FieldAlign = TypeSize;
1974  }
1975  }
1976  }
1977 
1978  // When used as part of a typedef, or together with a 'packed' attribute, the
1979  // 'aligned' attribute can be used to decrease alignment. In that case, it
1980  // overrides any computed alignment we have, and there is no need to upgrade
1981  // the alignment.
1982  auto alignedAttrCanDecreaseAIXAlignment = [AlignRequirement, FieldPacked] {
1983  // Enum alignment sources can be safely ignored here, because this only
1984  // helps decide whether we need the AIX alignment upgrade, which only
1985  // applies to floating-point types.
1986  return AlignRequirement == AlignRequirementKind::RequiredByTypedef ||
1987  (AlignRequirement == AlignRequirementKind::RequiredByRecord &&
1988  FieldPacked);
1989  };
1990 
1991  // The AIX `power` alignment rules apply the natural alignment of the
1992  // "first member" if it is of a floating-point data type (or is an aggregate
1993  // whose recursively "first" member or element is such a type). The alignment
1994  // associated with these types for subsequent members use an alignment value
1995  // where the floating-point data type is considered to have 4-byte alignment.
1996  //
1997  // For the purposes of the foregoing: vtable pointers, non-empty base classes,
1998  // and zero-width bit-fields count as prior members; members of empty class
1999  // types marked `no_unique_address` are not considered to be prior members.
2000  CharUnits PreferredAlign = FieldAlign;
2001  if (DefaultsToAIXPowerAlignment && !alignedAttrCanDecreaseAIXAlignment() &&
2002  (FoundFirstNonOverlappingEmptyFieldForAIX || IsNaturalAlign)) {
2003  auto performBuiltinTypeAlignmentUpgrade = [&](const BuiltinType *BTy) {
2004  if (BTy->getKind() == BuiltinType::Double ||
2005  BTy->getKind() == BuiltinType::LongDouble) {
2006  assert(PreferredAlign == CharUnits::fromQuantity(4) &&
2007  "No need to upgrade the alignment value.");
2008  PreferredAlign = CharUnits::fromQuantity(8);
2009  }
2010  };
2011 
2012  const Type *BaseTy = D->getType()->getBaseElementTypeUnsafe();
2013  if (const ComplexType *CTy = BaseTy->getAs<ComplexType>()) {
2014  performBuiltinTypeAlignmentUpgrade(
2015  CTy->getElementType()->castAs<BuiltinType>());
2016  } else if (const BuiltinType *BTy = BaseTy->getAs<BuiltinType>()) {
2017  performBuiltinTypeAlignmentUpgrade(BTy);
2018  } else if (const RecordType *RT = BaseTy->getAs<RecordType>()) {
2019  const RecordDecl *RD = RT->getDecl();
2020  assert(RD && "Expected non-null RecordDecl.");
2021  const ASTRecordLayout &FieldRecord = Context.getASTRecordLayout(RD);
2022  PreferredAlign = FieldRecord.getPreferredAlignment();
2023  }
2024  }
2025 
2026  // The align if the field is not packed. This is to check if the attribute
2027  // was unnecessary (-Wpacked).
2028  CharUnits UnpackedFieldAlign =
2029  !DefaultsToAIXPowerAlignment ? FieldAlign : PreferredAlign;
2030  CharUnits UnpackedFieldOffset = FieldOffset;
2031  CharUnits OriginalFieldAlign = UnpackedFieldAlign;
2032 
2033  if (FieldPacked) {
2034  FieldAlign = CharUnits::One();
2035  PreferredAlign = CharUnits::One();
2036  }
2037  CharUnits MaxAlignmentInChars =
2038  Context.toCharUnitsFromBits(D->getMaxAlignment());
2039  FieldAlign = std::max(FieldAlign, MaxAlignmentInChars);
2040  PreferredAlign = std::max(PreferredAlign, MaxAlignmentInChars);
2041  UnpackedFieldAlign = std::max(UnpackedFieldAlign, MaxAlignmentInChars);
2042 
2043  // The maximum field alignment overrides the aligned attribute.
2044  if (!MaxFieldAlignment.isZero()) {
2045  FieldAlign = std::min(FieldAlign, MaxFieldAlignment);
2046  PreferredAlign = std::min(PreferredAlign, MaxFieldAlignment);
2047  UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignment);
2048  }
2049 
2050  CharUnits AlignTo =
2051  !DefaultsToAIXPowerAlignment ? FieldAlign : PreferredAlign;
2052  // Round up the current record size to the field's alignment boundary.
2053  FieldOffset = FieldOffset.alignTo(AlignTo);
2054  UnpackedFieldOffset = UnpackedFieldOffset.alignTo(UnpackedFieldAlign);
2055 
2056  if (UseExternalLayout) {
2057  FieldOffset = Context.toCharUnitsFromBits(
2058  updateExternalFieldOffset(D, Context.toBits(FieldOffset)));
2059 
2060  if (!IsUnion && EmptySubobjects) {
2061  // Record the fact that we're placing a field at this offset.
2062  bool Allowed = EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset);
2063  (void)Allowed;
2064  assert(Allowed && "Externally-placed field cannot be placed here");
2065  }
2066  } else {
2067  if (!IsUnion && EmptySubobjects) {
2068  // Check if we can place the field at this offset.
2069  while (!EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset)) {
2070  // We couldn't place the field at the offset. Try again at a new offset.
2071  // We try offset 0 (for an empty field) and then dsize(C) onwards.
2072  if (FieldOffset == CharUnits::Zero() &&
2073  getDataSize() != CharUnits::Zero())
2074  FieldOffset = getDataSize().alignTo(AlignTo);
2075  else
2076  FieldOffset += AlignTo;
2077  }
2078  }
2079  }
2080 
2081  // Place this field at the current location.
2082  FieldOffsets.push_back(Context.toBits(FieldOffset));
2083 
2084  if (!UseExternalLayout)
2085  CheckFieldPadding(Context.toBits(FieldOffset), UnpaddedFieldOffset,
2086  Context.toBits(UnpackedFieldOffset),
2087  Context.toBits(UnpackedFieldAlign), FieldPacked, D);
2088 
2089  if (InsertExtraPadding) {
2090  CharUnits ASanAlignment = CharUnits::fromQuantity(8);
2091  CharUnits ExtraSizeForAsan = ASanAlignment;
2092  if (FieldSize % ASanAlignment)
2093  ExtraSizeForAsan +=
2094  ASanAlignment - CharUnits::fromQuantity(FieldSize % ASanAlignment);
2095  EffectiveFieldSize = FieldSize = FieldSize + ExtraSizeForAsan;
2096  }
2097 
2098  // Reserve space for this field.
2099  if (!IsOverlappingEmptyField) {
2100  uint64_t EffectiveFieldSizeInBits = Context.toBits(EffectiveFieldSize);
2101  if (IsUnion)
2102  setDataSize(std::max(getDataSizeInBits(), EffectiveFieldSizeInBits));
2103  else
2104  setDataSize(FieldOffset + EffectiveFieldSize);
2105 
2106  PaddedFieldSize = std::max(PaddedFieldSize, FieldOffset + FieldSize);
2107  setSize(std::max(getSizeInBits(), getDataSizeInBits()));
2108  } else {
2109  setSize(std::max(getSizeInBits(),
2110  (uint64_t)Context.toBits(FieldOffset + FieldSize)));
2111  }
2112 
2113  // Remember max struct/class ABI-specified alignment.
2114  UnadjustedAlignment = std::max(UnadjustedAlignment, FieldAlign);
2115  UpdateAlignment(FieldAlign, UnpackedFieldAlign, PreferredAlign);
2116 
2117  // For checking the alignment of inner fields against
2118  // the alignment of its parent record.
2119  if (const RecordDecl *RD = D->getParent()) {
2120  // Check if packed attribute or pragma pack is present.
2121  if (RD->hasAttr<PackedAttr>() || !MaxFieldAlignment.isZero())
2122  if (FieldAlign < OriginalFieldAlign)
2123  if (D->getType()->isRecordType()) {
2124  // If the offset is a multiple of the alignment of
2125  // the type, raise the warning.
2126  // TODO: Takes no account the alignment of the outer struct
2127  if (FieldOffset % OriginalFieldAlign != 0)
2128  Diag(D->getLocation(), diag::warn_unaligned_access)
2129  << Context.getTypeDeclType(RD) << D->getName() << D->getType();
2130  }
2131  }
2132 }
2133 
2134 void ItaniumRecordLayoutBuilder::FinishLayout(const NamedDecl *D) {
2135  // In C++, records cannot be of size 0.
2136  if (Context.getLangOpts().CPlusPlus && getSizeInBits() == 0) {
2137  if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
2138  // Compatibility with gcc requires a class (pod or non-pod)
2139  // which is not empty but of size 0; such as having fields of
2140  // array of zero-length, remains of Size 0
2141  if (RD->isEmpty())
2142  setSize(CharUnits::One());
2143  }
2144  else
2145  setSize(CharUnits::One());
2146  }
2147 
2148  // If we have any remaining field tail padding, include that in the overall
2149  // size.
2150  setSize(std::max(getSizeInBits(), (uint64_t)Context.toBits(PaddedFieldSize)));
2151 
2152  // Finally, round the size of the record up to the alignment of the
2153  // record itself.
2154  uint64_t UnpaddedSize = getSizeInBits() - UnfilledBitsInLastUnit;
2155  uint64_t UnpackedSizeInBits =
2156  llvm::alignTo(getSizeInBits(), Context.toBits(UnpackedAlignment));
2157 
2158  uint64_t RoundedSize = llvm::alignTo(
2159  getSizeInBits(),
2160  Context.toBits(!Context.getTargetInfo().defaultsToAIXPowerAlignment()
2161  ? Alignment
2162  : PreferredAlignment));
2163 
2164  if (UseExternalLayout) {
2165  // If we're inferring alignment, and the external size is smaller than
2166  // our size after we've rounded up to alignment, conservatively set the
2167  // alignment to 1.
2168  if (InferAlignment && External.Size < RoundedSize) {
2169  Alignment = CharUnits::One();
2170  PreferredAlignment = CharUnits::One();
2171  InferAlignment = false;
2172  }
2173  setSize(External.Size);
2174  return;
2175  }
2176 
2177  // Set the size to the final size.
2178  setSize(RoundedSize);
2179 
2180  unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
2181  if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
2182  // Warn if padding was introduced to the struct/class/union.
2183  if (getSizeInBits() > UnpaddedSize) {
2184  unsigned PadSize = getSizeInBits() - UnpaddedSize;
2185  bool InBits = true;
2186  if (PadSize % CharBitNum == 0) {
2187  PadSize = PadSize / CharBitNum;
2188  InBits = false;
2189  }
2190  Diag(RD->getLocation(), diag::warn_padded_struct_size)
2191  << Context.getTypeDeclType(RD)
2192  << PadSize
2193  << (InBits ? 1 : 0); // (byte|bit)
2194  }
2195 
2196  // Warn if we packed it unnecessarily, when the unpacked alignment is not
2197  // greater than the one after packing, the size in bits doesn't change and
2198  // the offset of each field is identical.
2199  if (Packed && UnpackedAlignment <= Alignment &&
2200  UnpackedSizeInBits == getSizeInBits() && !HasPackedField)
2201  Diag(D->getLocation(), diag::warn_unnecessary_packed)
2202  << Context.getTypeDeclType(RD);
2203  }
2204 }
2205 
2206 void ItaniumRecordLayoutBuilder::UpdateAlignment(
2207  CharUnits NewAlignment, CharUnits UnpackedNewAlignment,
2208  CharUnits PreferredNewAlignment) {
2209  // The alignment is not modified when using 'mac68k' alignment or when
2210  // we have an externally-supplied layout that also provides overall alignment.
2211  if (IsMac68kAlign || (UseExternalLayout && !InferAlignment))
2212  return;
2213 
2214  if (NewAlignment > Alignment) {
2215  assert(llvm::isPowerOf2_64(NewAlignment.getQuantity()) &&
2216  "Alignment not a power of 2");
2217  Alignment = NewAlignment;
2218  }
2219 
2220  if (UnpackedNewAlignment > UnpackedAlignment) {
2221  assert(llvm::isPowerOf2_64(UnpackedNewAlignment.getQuantity()) &&
2222  "Alignment not a power of 2");
2223  UnpackedAlignment = UnpackedNewAlignment;
2224  }
2225 
2226  if (PreferredNewAlignment > PreferredAlignment) {
2227  assert(llvm::isPowerOf2_64(PreferredNewAlignment.getQuantity()) &&
2228  "Alignment not a power of 2");
2229  PreferredAlignment = PreferredNewAlignment;
2230  }
2231 }
2232 
2233 uint64_t
2234 ItaniumRecordLayoutBuilder::updateExternalFieldOffset(const FieldDecl *Field,
2235  uint64_t ComputedOffset) {
2236  uint64_t ExternalFieldOffset = External.getExternalFieldOffset(Field);
2237 
2238  if (InferAlignment && ExternalFieldOffset < ComputedOffset) {
2239  // The externally-supplied field offset is before the field offset we
2240  // computed. Assume that the structure is packed.
2241  Alignment = CharUnits::One();
2242  PreferredAlignment = CharUnits::One();
2243  InferAlignment = false;
2244  }
2245 
2246  // Use the externally-supplied field offset.
2247  return ExternalFieldOffset;
2248 }
2249 
2250 /// Get diagnostic %select index for tag kind for
2251 /// field padding diagnostic message.
2252 /// WARNING: Indexes apply to particular diagnostics only!
2253 ///
2254 /// \returns diagnostic %select index.
2256  switch (Tag) {
2257  case TTK_Struct: return 0;
2258  case TTK_Interface: return 1;
2259  case TTK_Class: return 2;
2260  default: llvm_unreachable("Invalid tag kind for field padding diagnostic!");
2261  }
2262 }
2263 
2264 void ItaniumRecordLayoutBuilder::CheckFieldPadding(
2265  uint64_t Offset, uint64_t UnpaddedOffset, uint64_t UnpackedOffset,
2266  unsigned UnpackedAlign, bool isPacked, const FieldDecl *D) {
2267  // We let objc ivars without warning, objc interfaces generally are not used
2268  // for padding tricks.
2269  if (isa<ObjCIvarDecl>(D))
2270  return;
2271 
2272  // Don't warn about structs created without a SourceLocation. This can
2273  // be done by clients of the AST, such as codegen.
2274  if (D->getLocation().isInvalid())
2275  return;
2276 
2277  unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
2278 
2279  // Warn if padding was introduced to the struct/class.
2280  if (!IsUnion && Offset > UnpaddedOffset) {
2281  unsigned PadSize = Offset - UnpaddedOffset;
2282  bool InBits = true;
2283  if (PadSize % CharBitNum == 0) {
2284  PadSize = PadSize / CharBitNum;
2285  InBits = false;
2286  }
2287  if (D->getIdentifier())
2288  Diag(D->getLocation(), diag::warn_padded_struct_field)
2290  << Context.getTypeDeclType(D->getParent())
2291  << PadSize
2292  << (InBits ? 1 : 0) // (byte|bit)
2293  << D->getIdentifier();
2294  else
2295  Diag(D->getLocation(), diag::warn_padded_struct_anon_field)
2297  << Context.getTypeDeclType(D->getParent())
2298  << PadSize
2299  << (InBits ? 1 : 0); // (byte|bit)
2300  }
2301  if (isPacked && Offset != UnpackedOffset) {
2302  HasPackedField = true;
2303  }
2304 }
2305 
2307  const CXXRecordDecl *RD) {
2308  // If a class isn't polymorphic it doesn't have a key function.
2309  if (!RD->isPolymorphic())
2310  return nullptr;
2311 
2312  // A class that is not externally visible doesn't have a key function. (Or
2313  // at least, there's no point to assigning a key function to such a class;
2314  // this doesn't affect the ABI.)
2315  if (!RD->isExternallyVisible())
2316  return nullptr;
2317 
2318  // Template instantiations don't have key functions per Itanium C++ ABI 5.2.6.
2319  // Same behavior as GCC.
2321  if (TSK == TSK_ImplicitInstantiation ||
2324  return nullptr;
2325 
2326  bool allowInlineFunctions =
2328 
2329  for (const CXXMethodDecl *MD : RD->methods()) {
2330  if (!MD->isVirtual())
2331  continue;
2332 
2333  if (MD->isPure())
2334  continue;
2335 
2336  // Ignore implicit member functions, they are always marked as inline, but
2337  // they don't have a body until they're defined.
2338  if (MD->isImplicit())
2339  continue;
2340 
2341  if (MD->isInlineSpecified() || MD->isConstexpr())
2342  continue;
2343 
2344  if (MD->hasInlineBody())
2345  continue;
2346 
2347  // Ignore inline deleted or defaulted functions.
2348  if (!MD->isUserProvided())
2349  continue;
2350 
2351  // In certain ABIs, ignore functions with out-of-line inline definitions.
2352  if (!allowInlineFunctions) {
2353  const FunctionDecl *Def;
2354  if (MD->hasBody(Def) && Def->isInlineSpecified())
2355  continue;
2356  }
2357 
2358  if (Context.getLangOpts().CUDA) {
2359  // While compiler may see key method in this TU, during CUDA
2360  // compilation we should ignore methods that are not accessible
2361  // on this side of compilation.
2362  if (Context.getLangOpts().CUDAIsDevice) {
2363  // In device mode ignore methods without __device__ attribute.
2364  if (!MD->hasAttr<CUDADeviceAttr>())
2365  continue;
2366  } else {
2367  // In host mode ignore __device__-only methods.
2368  if (!MD->hasAttr<CUDAHostAttr>() && MD->hasAttr<CUDADeviceAttr>())
2369  continue;
2370  }
2371  }
2372 
2373  // If the key function is dllimport but the class isn't, then the class has
2374  // no key function. The DLL that exports the key function won't export the
2375  // vtable in this case.
2376  if (MD->hasAttr<DLLImportAttr>() && !RD->hasAttr<DLLImportAttr>() &&
2377  !Context.getTargetInfo().hasPS4DLLImportExport())
2378  return nullptr;
2379 
2380  // We found it.
2381  return MD;
2382  }
2383 
2384  return nullptr;
2385 }
2386 
2388  unsigned DiagID) {
2389  return Context.getDiagnostics().Report(Loc, DiagID);
2390 }
2391 
2392 /// Does the target C++ ABI require us to skip over the tail-padding
2393 /// of the given class (considering it as a base class) when allocating
2394 /// objects?
2395 static bool mustSkipTailPadding(TargetCXXABI ABI, const CXXRecordDecl *RD) {
2396  switch (ABI.getTailPaddingUseRules()) {
2398  return false;
2399 
2401  // FIXME: To the extent that this is meant to cover the Itanium ABI
2402  // rules, we should implement the restrictions about over-sized
2403  // bitfields:
2404  //
2405  // http://itanium-cxx-abi.github.io/cxx-abi/abi.html#POD :
2406  // In general, a type is considered a POD for the purposes of
2407  // layout if it is a POD type (in the sense of ISO C++
2408  // [basic.types]). However, a POD-struct or POD-union (in the
2409  // sense of ISO C++ [class]) with a bitfield member whose
2410  // declared width is wider than the declared type of the
2411  // bitfield is not a POD for the purpose of layout. Similarly,
2412  // an array type is not a POD for the purpose of layout if the
2413  // element type of the array is not a POD for the purpose of
2414  // layout.
2415  //
2416  // Where references to the ISO C++ are made in this paragraph,
2417  // the Technical Corrigendum 1 version of the standard is
2418  // intended.
2419  return RD->isPOD();
2420 
2422  // This is equivalent to RD->getTypeForDecl().isCXX11PODType(),
2423  // but with a lot of abstraction penalty stripped off. This does
2424  // assume that these properties are set correctly even in C++98
2425  // mode; fortunately, that is true because we want to assign
2426  // consistently semantics to the type-traits intrinsics (or at
2427  // least as many of them as possible).
2428  return RD->isTrivial() && RD->isCXX11StandardLayout();
2429  }
2430 
2431  llvm_unreachable("bad tail-padding use kind");
2432 }
2433 
2434 static bool isMsLayout(const ASTContext &Context) {
2435  return Context.getTargetInfo().getCXXABI().isMicrosoft();
2436 }
2437 
2438 // This section contains an implementation of struct layout that is, up to the
2439 // included tests, compatible with cl.exe (2013). The layout produced is
2440 // significantly different than those produced by the Itanium ABI. Here we note
2441 // the most important differences.
2442 //
2443 // * The alignment of bitfields in unions is ignored when computing the
2444 // alignment of the union.
2445 // * The existence of zero-width bitfield that occurs after anything other than
2446 // a non-zero length bitfield is ignored.
2447 // * There is no explicit primary base for the purposes of layout. All bases
2448 // with vfptrs are laid out first, followed by all bases without vfptrs.
2449 // * The Itanium equivalent vtable pointers are split into a vfptr (virtual
2450 // function pointer) and a vbptr (virtual base pointer). They can each be
2451 // shared with a, non-virtual bases. These bases need not be the same. vfptrs
2452 // always occur at offset 0. vbptrs can occur at an arbitrary offset and are
2453 // placed after the lexicographically last non-virtual base. This placement
2454 // is always before fields but can be in the middle of the non-virtual bases
2455 // due to the two-pass layout scheme for non-virtual-bases.
2456 // * Virtual bases sometimes require a 'vtordisp' field that is laid out before
2457 // the virtual base and is used in conjunction with virtual overrides during
2458 // construction and destruction. This is always a 4 byte value and is used as
2459 // an alternative to constructor vtables.
2460 // * vtordisps are allocated in a block of memory with size and alignment equal
2461 // to the alignment of the completed structure (before applying __declspec(
2462 // align())). The vtordisp always occur at the end of the allocation block,
2463 // immediately prior to the virtual base.
2464 // * vfptrs are injected after all bases and fields have been laid out. In
2465 // order to guarantee proper alignment of all fields, the vfptr injection
2466 // pushes all bases and fields back by the alignment imposed by those bases
2467 // and fields. This can potentially add a significant amount of padding.
2468 // vfptrs are always injected at offset 0.
2469 // * vbptrs are injected after all bases and fields have been laid out. In
2470 // order to guarantee proper alignment of all fields, the vfptr injection
2471 // pushes all bases and fields back by the alignment imposed by those bases
2472 // and fields. This can potentially add a significant amount of padding.
2473 // vbptrs are injected immediately after the last non-virtual base as
2474 // lexicographically ordered in the code. If this site isn't pointer aligned
2475 // the vbptr is placed at the next properly aligned location. Enough padding
2476 // is added to guarantee a fit.
2477 // * The last zero sized non-virtual base can be placed at the end of the
2478 // struct (potentially aliasing another object), or may alias with the first
2479 // field, even if they are of the same type.
2480 // * The last zero size virtual base may be placed at the end of the struct
2481 // potentially aliasing another object.
2482 // * The ABI attempts to avoid aliasing of zero sized bases by adding padding
2483 // between bases or vbases with specific properties. The criteria for
2484 // additional padding between two bases is that the first base is zero sized
2485 // or ends with a zero sized subobject and the second base is zero sized or
2486 // trails with a zero sized base or field (sharing of vfptrs can reorder the
2487 // layout of the so the leading base is not always the first one declared).
2488 // This rule does take into account fields that are not records, so padding
2489 // will occur even if the last field is, e.g. an int. The padding added for
2490 // bases is 1 byte. The padding added between vbases depends on the alignment
2491 // of the object but is at least 4 bytes (in both 32 and 64 bit modes).
2492 // * There is no concept of non-virtual alignment, non-virtual alignment and
2493 // alignment are always identical.
2494 // * There is a distinction between alignment and required alignment.
2495 // __declspec(align) changes the required alignment of a struct. This
2496 // alignment is _always_ obeyed, even in the presence of #pragma pack. A
2497 // record inherits required alignment from all of its fields and bases.
2498 // * __declspec(align) on bitfields has the effect of changing the bitfield's
2499 // alignment instead of its required alignment. This is the only known way
2500 // to make the alignment of a struct bigger than 8. Interestingly enough
2501 // this alignment is also immune to the effects of #pragma pack and can be
2502 // used to create structures with large alignment under #pragma pack.
2503 // However, because it does not impact required alignment, such a structure,
2504 // when used as a field or base, will not be aligned if #pragma pack is
2505 // still active at the time of use.
2506 //
2507 // Known incompatibilities:
2508 // * all: #pragma pack between fields in a record
2509 // * 2010 and back: If the last field in a record is a bitfield, every object
2510 // laid out after the record will have extra padding inserted before it. The
2511 // extra padding will have size equal to the size of the storage class of the
2512 // bitfield. 0 sized bitfields don't exhibit this behavior and the extra
2513 // padding can be avoided by adding a 0 sized bitfield after the non-zero-
2514 // sized bitfield.
2515 // * 2012 and back: In 64-bit mode, if the alignment of a record is 16 or
2516 // greater due to __declspec(align()) then a second layout phase occurs after
2517 // The locations of the vf and vb pointers are known. This layout phase
2518 // suffers from the "last field is a bitfield" bug in 2010 and results in
2519 // _every_ field getting padding put in front of it, potentially including the
2520 // vfptr, leaving the vfprt at a non-zero location which results in a fault if
2521 // anything tries to read the vftbl. The second layout phase also treats
2522 // bitfields as separate entities and gives them each storage rather than
2523 // packing them. Additionally, because this phase appears to perform a
2524 // (an unstable) sort on the members before laying them out and because merged
2525 // bitfields have the same address, the bitfields end up in whatever order
2526 // the sort left them in, a behavior we could never hope to replicate.
2527 
2528 namespace {
2529 struct MicrosoftRecordLayoutBuilder {
2530  struct ElementInfo {
2531  CharUnits Size;
2532  CharUnits Alignment;
2533  };
2534  typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
2535  MicrosoftRecordLayoutBuilder(const ASTContext &Context) : Context(Context) {}
2536 private:
2537  MicrosoftRecordLayoutBuilder(const MicrosoftRecordLayoutBuilder &) = delete;
2538  void operator=(const MicrosoftRecordLayoutBuilder &) = delete;
2539 public:
2540  void layout(const RecordDecl *RD);
2541  void cxxLayout(const CXXRecordDecl *RD);
2542  /// Initializes size and alignment and honors some flags.
2543  void initializeLayout(const RecordDecl *RD);
2544  /// Initialized C++ layout, compute alignment and virtual alignment and
2545  /// existence of vfptrs and vbptrs. Alignment is needed before the vfptr is
2546  /// laid out.
2547  void initializeCXXLayout(const CXXRecordDecl *RD);
2548  void layoutNonVirtualBases(const CXXRecordDecl *RD);
2549  void layoutNonVirtualBase(const CXXRecordDecl *RD,
2550  const CXXRecordDecl *BaseDecl,
2551  const ASTRecordLayout &BaseLayout,
2552  const ASTRecordLayout *&PreviousBaseLayout);
2553  void injectVFPtr(const CXXRecordDecl *RD);
2554  void injectVBPtr(const CXXRecordDecl *RD);
2555  /// Lays out the fields of the record. Also rounds size up to
2556  /// alignment.
2557  void layoutFields(const RecordDecl *RD);
2558  void layoutField(const FieldDecl *FD);
2559  void layoutBitField(const FieldDecl *FD);
2560  /// Lays out a single zero-width bit-field in the record and handles
2561  /// special cases associated with zero-width bit-fields.
2562  void layoutZeroWidthBitField(const FieldDecl *FD);
2563  void layoutVirtualBases(const CXXRecordDecl *RD);
2564  void finalizeLayout(const RecordDecl *RD);
2565  /// Gets the size and alignment of a base taking pragma pack and
2566  /// __declspec(align) into account.
2567  ElementInfo getAdjustedElementInfo(const ASTRecordLayout &Layout);
2568  /// Gets the size and alignment of a field taking pragma pack and
2569  /// __declspec(align) into account. It also updates RequiredAlignment as a
2570  /// side effect because it is most convenient to do so here.
2571  ElementInfo getAdjustedElementInfo(const FieldDecl *FD);
2572  /// Places a field at an offset in CharUnits.
2573  void placeFieldAtOffset(CharUnits FieldOffset) {
2574  FieldOffsets.push_back(Context.toBits(FieldOffset));
2575  }
2576  /// Places a bitfield at a bit offset.
2577  void placeFieldAtBitOffset(uint64_t FieldOffset) {
2578  FieldOffsets.push_back(FieldOffset);
2579  }
2580  /// Compute the set of virtual bases for which vtordisps are required.
2581  void computeVtorDispSet(
2582  llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtorDispSet,
2583  const CXXRecordDecl *RD) const;
2584  const ASTContext &Context;
2585  /// The size of the record being laid out.
2586  CharUnits Size;
2587  /// The non-virtual size of the record layout.
2588  CharUnits NonVirtualSize;
2589  /// The data size of the record layout.
2590  CharUnits DataSize;
2591  /// The current alignment of the record layout.
2592  CharUnits Alignment;
2593  /// The maximum allowed field alignment. This is set by #pragma pack.
2594  CharUnits MaxFieldAlignment;
2595  /// The alignment that this record must obey. This is imposed by
2596  /// __declspec(align()) on the record itself or one of its fields or bases.
2597  CharUnits RequiredAlignment;
2598  /// The size of the allocation of the currently active bitfield.
2599  /// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield
2600  /// is true.
2601  CharUnits CurrentBitfieldSize;
2602  /// Offset to the virtual base table pointer (if one exists).
2603  CharUnits VBPtrOffset;
2604  /// Minimum record size possible.
2605  CharUnits MinEmptyStructSize;
2606  /// The size and alignment info of a pointer.
2607  ElementInfo PointerInfo;
2608  /// The primary base class (if one exists).
2609  const CXXRecordDecl *PrimaryBase;
2610  /// The class we share our vb-pointer with.
2611  const CXXRecordDecl *SharedVBPtrBase;
2612  /// The collection of field offsets.
2613  SmallVector<uint64_t, 16> FieldOffsets;
2614  /// Base classes and their offsets in the record.
2615  BaseOffsetsMapTy Bases;
2616  /// virtual base classes and their offsets in the record.
2618  /// The number of remaining bits in our last bitfield allocation.
2619  /// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield is
2620  /// true.
2621  unsigned RemainingBitsInField;
2622  bool IsUnion : 1;
2623  /// True if the last field laid out was a bitfield and was not 0
2624  /// width.
2625  bool LastFieldIsNonZeroWidthBitfield : 1;
2626  /// True if the class has its own vftable pointer.
2627  bool HasOwnVFPtr : 1;
2628  /// True if the class has a vbtable pointer.
2629  bool HasVBPtr : 1;
2630  /// True if the last sub-object within the type is zero sized or the
2631  /// object itself is zero sized. This *does not* count members that are not
2632  /// records. Only used for MS-ABI.
2633  bool EndsWithZeroSizedObject : 1;
2634  /// True if this class is zero sized or first base is zero sized or
2635  /// has this property. Only used for MS-ABI.
2636  bool LeadsWithZeroSizedBase : 1;
2637 
2638  /// True if the external AST source provided a layout for this record.
2639  bool UseExternalLayout : 1;
2640 
2641  /// The layout provided by the external AST source. Only active if
2642  /// UseExternalLayout is true.
2643  ExternalLayout External;
2644 };
2645 } // namespace
2646 
2647 MicrosoftRecordLayoutBuilder::ElementInfo
2648 MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
2649  const ASTRecordLayout &Layout) {
2650  ElementInfo Info;
2651  Info.Alignment = Layout.getAlignment();
2652  // Respect pragma pack.
2653  if (!MaxFieldAlignment.isZero())
2654  Info.Alignment = std::min(Info.Alignment, MaxFieldAlignment);
2655  // Track zero-sized subobjects here where it's already available.
2656  EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
2657  // Respect required alignment, this is necessary because we may have adjusted
2658  // the alignment in the case of pragma pack. Note that the required alignment
2659  // doesn't actually apply to the struct alignment at this point.
2660  Alignment = std::max(Alignment, Info.Alignment);
2661  RequiredAlignment = std::max(RequiredAlignment, Layout.getRequiredAlignment());
2662  Info.Alignment = std::max(Info.Alignment, Layout.getRequiredAlignment());
2663  Info.Size = Layout.getNonVirtualSize();
2664  return Info;
2665 }
2666 
2667 MicrosoftRecordLayoutBuilder::ElementInfo
2668 MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
2669  const FieldDecl *FD) {
2670  // Get the alignment of the field type's natural alignment, ignore any
2671  // alignment attributes.
2672  auto TInfo =
2674  ElementInfo Info{TInfo.Width, TInfo.Align};
2675  // Respect align attributes on the field.
2676  CharUnits FieldRequiredAlignment =
2677  Context.toCharUnitsFromBits(FD->getMaxAlignment());
2678  // Respect align attributes on the type.
2679  if (Context.isAlignmentRequired(FD->getType()))
2680  FieldRequiredAlignment = std::max(
2681  Context.getTypeAlignInChars(FD->getType()), FieldRequiredAlignment);
2682  // Respect attributes applied to subobjects of the field.
2683  if (FD->isBitField())
2684  // For some reason __declspec align impacts alignment rather than required
2685  // alignment when it is applied to bitfields.
2686  Info.Alignment = std::max(Info.Alignment, FieldRequiredAlignment);
2687  else {
2688  if (auto RT =
2690  auto const &Layout = Context.getASTRecordLayout(RT->getDecl());
2691  EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
2692  FieldRequiredAlignment = std::max(FieldRequiredAlignment,
2693  Layout.getRequiredAlignment());
2694  }
2695  // Capture required alignment as a side-effect.
2696  RequiredAlignment = std::max(RequiredAlignment, FieldRequiredAlignment);
2697  }
2698  // Respect pragma pack, attribute pack and declspec align
2699  if (!MaxFieldAlignment.isZero())
2700  Info.Alignment = std::min(Info.Alignment, MaxFieldAlignment);
2701  if (FD->hasAttr<PackedAttr>())
2702  Info.Alignment = CharUnits::One();
2703  Info.Alignment = std::max(Info.Alignment, FieldRequiredAlignment);
2704  return Info;
2705 }
2706 
2707 void MicrosoftRecordLayoutBuilder::layout(const RecordDecl *RD) {
2708  // For C record layout, zero-sized records always have size 4.
2709  MinEmptyStructSize = CharUnits::fromQuantity(4);
2710  initializeLayout(RD);
2711  layoutFields(RD);
2712  DataSize = Size = Size.alignTo(Alignment);
2713  RequiredAlignment = std::max(
2714  RequiredAlignment, Context.toCharUnitsFromBits(RD->getMaxAlignment()));
2715  finalizeLayout(RD);
2716 }
2717 
2718 void MicrosoftRecordLayoutBuilder::cxxLayout(const CXXRecordDecl *RD) {
2719  // The C++ standard says that empty structs have size 1.
2720  MinEmptyStructSize = CharUnits::One();
2721  initializeLayout(RD);
2722  initializeCXXLayout(RD);
2723  layoutNonVirtualBases(RD);
2724  layoutFields(RD);
2725  injectVBPtr(RD);
2726  injectVFPtr(RD);
2727  if (HasOwnVFPtr || (HasVBPtr && !SharedVBPtrBase))
2728  Alignment = std::max(Alignment, PointerInfo.Alignment);
2729  auto RoundingAlignment = Alignment;
2730  if (!MaxFieldAlignment.isZero())
2731  RoundingAlignment = std::min(RoundingAlignment, MaxFieldAlignment);
2732  if (!UseExternalLayout)
2733  Size = Size.alignTo(RoundingAlignment);
2734  NonVirtualSize = Size;
2735  RequiredAlignment = std::max(
2736  RequiredAlignment, Context.toCharUnitsFromBits(RD->getMaxAlignment()));
2737  layoutVirtualBases(RD);
2738  finalizeLayout(RD);
2739 }
2740 
2741 void MicrosoftRecordLayoutBuilder::initializeLayout(const RecordDecl *RD) {
2742  IsUnion = RD->isUnion();
2743  Size = CharUnits::Zero();
2744  Alignment = CharUnits::One();
2745  // In 64-bit mode we always perform an alignment step after laying out vbases.
2746  // In 32-bit mode we do not. The check to see if we need to perform alignment
2747  // checks the RequiredAlignment field and performs alignment if it isn't 0.
2748  RequiredAlignment = Context.getTargetInfo().getTriple().isArch64Bit()
2749  ? CharUnits::One()
2750  : CharUnits::Zero();
2751  // Compute the maximum field alignment.
2752  MaxFieldAlignment = CharUnits::Zero();
2753  // Honor the default struct packing maximum alignment flag.
2754  if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct)
2755  MaxFieldAlignment = CharUnits::fromQuantity(DefaultMaxFieldAlignment);
2756  // Honor the packing attribute. The MS-ABI ignores pragma pack if its larger
2757  // than the pointer size.
2758  if (const MaxFieldAlignmentAttr *MFAA = RD->getAttr<MaxFieldAlignmentAttr>()){
2759  unsigned PackedAlignment = MFAA->getAlignment();
2760  if (PackedAlignment <= Context.getTargetInfo().getPointerWidth(0))
2761  MaxFieldAlignment = Context.toCharUnitsFromBits(PackedAlignment);
2762  }
2763  // Packed attribute forces max field alignment to be 1.
2764  if (RD->hasAttr<PackedAttr>())
2765  MaxFieldAlignment = CharUnits::One();
2766 
2767  // Try to respect the external layout if present.
2768  UseExternalLayout = false;
2769  if (ExternalASTSource *Source = Context.getExternalSource())
2770  UseExternalLayout = Source->layoutRecordType(
2771  RD, External.Size, External.Align, External.FieldOffsets,
2772  External.BaseOffsets, External.VirtualBaseOffsets);
2773 }
2774 
2775 void
2776 MicrosoftRecordLayoutBuilder::initializeCXXLayout(const CXXRecordDecl *RD) {
2777  EndsWithZeroSizedObject = false;
2778  LeadsWithZeroSizedBase = false;
2779  HasOwnVFPtr = false;
2780  HasVBPtr = false;
2781  PrimaryBase = nullptr;
2782  SharedVBPtrBase = nullptr;
2783  // Calculate pointer size and alignment. These are used for vfptr and vbprt
2784  // injection.
2785  PointerInfo.Size =
2786  Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
2787  PointerInfo.Alignment =
2788  Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(0));
2789  // Respect pragma pack.
2790  if (!MaxFieldAlignment.isZero())
2791  PointerInfo.Alignment = std::min(PointerInfo.Alignment, MaxFieldAlignment);
2792 }
2793 
2794 void
2795 MicrosoftRecordLayoutBuilder::layoutNonVirtualBases(const CXXRecordDecl *RD) {
2796  // The MS-ABI lays out all bases that contain leading vfptrs before it lays
2797  // out any bases that do not contain vfptrs. We implement this as two passes
2798  // over the bases. This approach guarantees that the primary base is laid out
2799  // first. We use these passes to calculate some additional aggregated
2800  // information about the bases, such as required alignment and the presence of
2801  // zero sized members.
2802  const ASTRecordLayout *PreviousBaseLayout = nullptr;
2803  bool HasPolymorphicBaseClass = false;
2804  // Iterate through the bases and lay out the non-virtual ones.
2805  for (const CXXBaseSpecifier &Base : RD->bases()) {
2806  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2807  HasPolymorphicBaseClass |= BaseDecl->isPolymorphic();
2808  const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2809  // Mark and skip virtual bases.
2810  if (Base.isVirtual()) {
2811  HasVBPtr = true;
2812  continue;
2813  }
2814  // Check for a base to share a VBPtr with.
2815  if (!SharedVBPtrBase && BaseLayout.hasVBPtr()) {
2816  SharedVBPtrBase = BaseDecl;
2817  HasVBPtr = true;
2818  }
2819  // Only lay out bases with extendable VFPtrs on the first pass.
2820  if (!BaseLayout.hasExtendableVFPtr())
2821  continue;
2822  // If we don't have a primary base, this one qualifies.
2823  if (!PrimaryBase) {
2824  PrimaryBase = BaseDecl;
2825  LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
2826  }
2827  // Lay out the base.
2828  layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
2829  }
2830  // Figure out if we need a fresh VFPtr for this class.
2831  if (RD->isPolymorphic()) {
2832  if (!HasPolymorphicBaseClass)
2833  // This class introduces polymorphism, so we need a vftable to store the
2834  // RTTI information.
2835  HasOwnVFPtr = true;
2836  else if (!PrimaryBase) {
2837  // We have a polymorphic base class but can't extend its vftable. Add a
2838  // new vfptr if we would use any vftable slots.
2839  for (CXXMethodDecl *M : RD->methods()) {
2841  M->size_overridden_methods() == 0) {
2842  HasOwnVFPtr = true;
2843  break;
2844  }
2845  }
2846  }
2847  }
2848  // If we don't have a primary base then we have a leading object that could
2849  // itself lead with a zero-sized object, something we track.
2850  bool CheckLeadingLayout = !PrimaryBase;
2851  // Iterate through the bases and lay out the non-virtual ones.
2852  for (const CXXBaseSpecifier &Base : RD->bases()) {
2853  if (Base.isVirtual())
2854  continue;
2855  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2856  const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2857  // Only lay out bases without extendable VFPtrs on the second pass.
2858  if (BaseLayout.hasExtendableVFPtr()) {
2859  VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
2860  continue;
2861  }
2862  // If this is the first layout, check to see if it leads with a zero sized
2863  // object. If it does, so do we.
2864  if (CheckLeadingLayout) {
2865  CheckLeadingLayout = false;
2866  LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
2867  }
2868  // Lay out the base.
2869  layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
2870  VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
2871  }
2872  // Set our VBPtroffset if we know it at this point.
2873  if (!HasVBPtr)
2874  VBPtrOffset = CharUnits::fromQuantity(-1);
2875  else if (SharedVBPtrBase) {
2876  const ASTRecordLayout &Layout = Context.getASTRecordLayout(SharedVBPtrBase);
2877  VBPtrOffset = Bases[SharedVBPtrBase] + Layout.getVBPtrOffset();
2878  }
2879 }
2880 
2881 static bool recordUsesEBO(const RecordDecl *RD) {
2882  if (!isa<CXXRecordDecl>(RD))
2883  return false;
2884  if (RD->hasAttr<EmptyBasesAttr>())
2885  return true;
2886  if (auto *LVA = RD->getAttr<LayoutVersionAttr>())
2887  // TODO: Double check with the next version of MSVC.
2888  if (LVA->getVersion() <= LangOptions::MSVC2015)
2889  return false;
2890  // TODO: Some later version of MSVC will change the default behavior of the
2891  // compiler to enable EBO by default. When this happens, we will need an
2892  // additional isCompatibleWithMSVC check.
2893  return false;
2894 }
2895 
2896 void MicrosoftRecordLayoutBuilder::layoutNonVirtualBase(
2897  const CXXRecordDecl *RD,
2898  const CXXRecordDecl *BaseDecl,
2899  const ASTRecordLayout &BaseLayout,
2900  const ASTRecordLayout *&PreviousBaseLayout) {
2901  // Insert padding between two bases if the left first one is zero sized or
2902  // contains a zero sized subobject and the right is zero sized or one leads
2903  // with a zero sized base.
2904  bool MDCUsesEBO = recordUsesEBO(RD);
2905  if (PreviousBaseLayout && PreviousBaseLayout->endsWithZeroSizedObject() &&
2906  BaseLayout.leadsWithZeroSizedBase() && !MDCUsesEBO)
2907  Size++;
2908  ElementInfo Info = getAdjustedElementInfo(BaseLayout);
2909  CharUnits BaseOffset;
2910 
2911  // Respect the external AST source base offset, if present.
2912  bool FoundBase = false;
2913  if (UseExternalLayout) {
2914  FoundBase = External.getExternalNVBaseOffset(BaseDecl, BaseOffset);
2915  if (FoundBase) {
2916  assert(BaseOffset >= Size && "base offset already allocated");
2917  Size = BaseOffset;
2918  }
2919  }
2920 
2921  if (!FoundBase) {
2922  if (MDCUsesEBO && BaseDecl->isEmpty()) {
2923  assert(BaseLayout.getNonVirtualSize() == CharUnits::Zero());
2924  BaseOffset = CharUnits::Zero();
2925  } else {
2926  // Otherwise, lay the base out at the end of the MDC.
2927  BaseOffset = Size = Size.alignTo(Info.Alignment);
2928  }
2929  }
2930  Bases.insert(std::make_pair(BaseDecl, BaseOffset));
2931  Size += BaseLayout.getNonVirtualSize();
2932  PreviousBaseLayout = &BaseLayout;
2933 }
2934 
2935 void MicrosoftRecordLayoutBuilder::layoutFields(const RecordDecl *RD) {
2936  LastFieldIsNonZeroWidthBitfield = false;
2937  for (const FieldDecl *Field : RD->fields())
2938  layoutField(Field);
2939 }
2940 
2941 void MicrosoftRecordLayoutBuilder::layoutField(const FieldDecl *FD) {
2942  if (FD->isBitField()) {
2943  layoutBitField(FD);
2944  return;
2945  }
2946  LastFieldIsNonZeroWidthBitfield = false;
2947  ElementInfo Info = getAdjustedElementInfo(FD);
2948  Alignment = std::max(Alignment, Info.Alignment);
2949  CharUnits FieldOffset;
2950  if (UseExternalLayout)
2951  FieldOffset =
2952  Context.toCharUnitsFromBits(External.getExternalFieldOffset(FD));
2953  else if (IsUnion)
2954  FieldOffset = CharUnits::Zero();
2955  else
2956  FieldOffset = Size.alignTo(Info.Alignment);
2957  placeFieldAtOffset(FieldOffset);
2958  Size = std::max(Size, FieldOffset + Info.Size);
2959 }
2960 
2961 void MicrosoftRecordLayoutBuilder::layoutBitField(const FieldDecl *FD) {
2962  unsigned Width = FD->getBitWidthValue(Context);
2963  if (Width == 0) {
2964  layoutZeroWidthBitField(FD);
2965  return;
2966  }
2967  ElementInfo Info = getAdjustedElementInfo(FD);
2968  // Clamp the bitfield to a containable size for the sake of being able
2969  // to lay them out. Sema will throw an error.
2970  if (Width > Context.toBits(Info.Size))
2971  Width = Context.toBits(Info.Size);
2972  // Check to see if this bitfield fits into an existing allocation. Note:
2973  // MSVC refuses to pack bitfields of formal types with different sizes
2974  // into the same allocation.
2975  if (!UseExternalLayout && !IsUnion && LastFieldIsNonZeroWidthBitfield &&
2976  CurrentBitfieldSize == Info.Size && Width <= RemainingBitsInField) {
2977  placeFieldAtBitOffset(Context.toBits(Size) - RemainingBitsInField);
2978  RemainingBitsInField -= Width;
2979  return;
2980  }
2981  LastFieldIsNonZeroWidthBitfield = true;
2982  CurrentBitfieldSize = Info.Size;
2983  if (UseExternalLayout) {
2984  auto FieldBitOffset = External.getExternalFieldOffset(FD);
2985  placeFieldAtBitOffset(FieldBitOffset);
2986  auto NewSize = Context.toCharUnitsFromBits(
2987  llvm::alignDown(FieldBitOffset, Context.toBits(Info.Alignment)) +
2988  Context.toBits(Info.Size));
2989  Size = std::max(Size, NewSize);
2990  Alignment = std::max(Alignment, Info.Alignment);
2991  } else if (IsUnion) {
2992  placeFieldAtOffset(CharUnits::Zero());
2993  Size = std::max(Size, Info.Size);
2994  // TODO: Add a Sema warning that MS ignores bitfield alignment in unions.
2995  } else {
2996  // Allocate a new block of memory and place the bitfield in it.
2997  CharUnits FieldOffset = Size.alignTo(Info.Alignment);
2998  placeFieldAtOffset(FieldOffset);
2999  Size = FieldOffset + Info.Size;
3000  Alignment = std::max(Alignment, Info.Alignment);
3001  RemainingBitsInField = Context.toBits(Info.Size) - Width;
3002  }
3003 }
3004 
3005 void
3006 MicrosoftRecordLayoutBuilder::layoutZeroWidthBitField(const FieldDecl *FD) {
3007  // Zero-width bitfields are ignored unless they follow a non-zero-width
3008  // bitfield.
3009  if (!LastFieldIsNonZeroWidthBitfield) {
3010  placeFieldAtOffset(IsUnion ? CharUnits::Zero() : Size);
3011  // TODO: Add a Sema warning that MS ignores alignment for zero
3012  // sized bitfields that occur after zero-size bitfields or non-bitfields.
3013  return;
3014  }
3015  LastFieldIsNonZeroWidthBitfield = false;
3016  ElementInfo Info = getAdjustedElementInfo(FD);
3017  if (IsUnion) {
3018  placeFieldAtOffset(CharUnits::Zero());
3019  Size = std::max(Size, Info.Size);
3020  // TODO: Add a Sema warning that MS ignores bitfield alignment in unions.
3021  } else {
3022  // Round up the current record size to the field's alignment boundary.
3023  CharUnits FieldOffset = Size.alignTo(Info.Alignment);
3024  placeFieldAtOffset(FieldOffset);
3025  Size = FieldOffset;
3026  Alignment = std::max(Alignment, Info.Alignment);
3027  }
3028 }
3029 
3030 void MicrosoftRecordLayoutBuilder::injectVBPtr(const CXXRecordDecl *RD) {
3031  if (!HasVBPtr || SharedVBPtrBase)
3032  return;
3033  // Inject the VBPointer at the injection site.
3034  CharUnits InjectionSite = VBPtrOffset;
3035  // But before we do, make sure it's properly aligned.
3036  VBPtrOffset = VBPtrOffset.alignTo(PointerInfo.Alignment);
3037  // Determine where the first field should be laid out after the vbptr.
3038  CharUnits FieldStart = VBPtrOffset + PointerInfo.Size;
3039  // Shift everything after the vbptr down, unless we're using an external
3040  // layout.
3041  if (UseExternalLayout) {
3042  // It is possible that there were no fields or bases located after vbptr,
3043  // so the size was not adjusted before.
3044  if (Size < FieldStart)
3045  Size = FieldStart;
3046  return;
3047  }
3048  // Make sure that the amount we push the fields back by is a multiple of the
3049  // alignment.
3050  CharUnits Offset = (FieldStart - InjectionSite)
3051  .alignTo(std::max(RequiredAlignment, Alignment));
3052  Size += Offset;
3053  for (uint64_t &FieldOffset : FieldOffsets)
3054  FieldOffset += Context.toBits(Offset);
3055  for (BaseOffsetsMapTy::value_type &Base : Bases)
3056  if (Base.second >= InjectionSite)
3057  Base.second += Offset;
3058 }
3059 
3060 void MicrosoftRecordLayoutBuilder::injectVFPtr(const CXXRecordDecl *RD) {
3061  if (!HasOwnVFPtr)
3062  return;
3063  // Make sure that the amount we push the struct back by is a multiple of the
3064  // alignment.
3065  CharUnits Offset =
3066  PointerInfo.Size.alignTo(std::max(RequiredAlignment, Alignment));
3067  // Push back the vbptr, but increase the size of the object and push back
3068  // regular fields by the offset only if not using external record layout.
3069  if (HasVBPtr)
3070  VBPtrOffset += Offset;
3071 
3072  if (UseExternalLayout) {
3073  // The class may have no bases or fields, but still have a vfptr
3074  // (e.g. it's an interface class). The size was not correctly set before
3075  // in this case.
3076  if (FieldOffsets.empty() && Bases.empty())
3077  Size += Offset;
3078  return;
3079  }
3080 
3081  Size += Offset;
3082 
3083  // If we're using an external layout, the fields offsets have already
3084  // accounted for this adjustment.
3085  for (uint64_t &FieldOffset : FieldOffsets)
3086  FieldOffset += Context.toBits(Offset);
3087  for (BaseOffsetsMapTy::value_type &Base : Bases)
3088  Base.second += Offset;
3089 }
3090 
3091 void MicrosoftRecordLayoutBuilder::layoutVirtualBases(const CXXRecordDecl *RD) {
3092  if (!HasVBPtr)
3093  return;
3094  // Vtordisps are always 4 bytes (even in 64-bit mode)
3095  CharUnits VtorDispSize = CharUnits::fromQuantity(4);
3096  CharUnits VtorDispAlignment = VtorDispSize;
3097  // vtordisps respect pragma pack.
3098  if (!MaxFieldAlignment.isZero())
3099  VtorDispAlignment = std::min(VtorDispAlignment, MaxFieldAlignment);
3100  // The alignment of the vtordisp is at least the required alignment of the
3101  // entire record. This requirement may be present to support vtordisp
3102  // injection.
3103  for (const CXXBaseSpecifier &VBase : RD->vbases()) {
3104  const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
3105  const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
3106  RequiredAlignment =
3107  std::max(RequiredAlignment, BaseLayout.getRequiredAlignment());
3108  }
3109  VtorDispAlignment = std::max(VtorDispAlignment, RequiredAlignment);
3110  // Compute the vtordisp set.
3112  computeVtorDispSet(HasVtorDispSet, RD);
3113  // Iterate through the virtual bases and lay them out.
3114  const ASTRecordLayout *PreviousBaseLayout = nullptr;
3115  for (const CXXBaseSpecifier &VBase : RD->vbases()) {
3116  const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
3117  const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
3118  bool HasVtordisp = HasVtorDispSet.contains(BaseDecl);
3119  // Insert padding between two bases if the left first one is zero sized or
3120  // contains a zero sized subobject and the right is zero sized or one leads
3121  // with a zero sized base. The padding between virtual bases is 4
3122  // bytes (in both 32 and 64 bits modes) and always involves rounding up to
3123  // the required alignment, we don't know why.
3124  if ((PreviousBaseLayout && PreviousBaseLayout->endsWithZeroSizedObject() &&
3125  BaseLayout.leadsWithZeroSizedBase() && !recordUsesEBO(RD)) ||
3126  HasVtordisp) {
3127  Size = Size.alignTo(VtorDispAlignment) + VtorDispSize;
3128  Alignment = std::max(VtorDispAlignment, Alignment);
3129  }
3130  // Insert the virtual base.
3131  ElementInfo Info = getAdjustedElementInfo(BaseLayout);
3132  CharUnits BaseOffset;
3133 
3134  // Respect the external AST source base offset, if present.
3135  if (UseExternalLayout) {
3136  if (!External.getExternalVBaseOffset(BaseDecl, BaseOffset))
3137  BaseOffset = Size;
3138  } else
3139  BaseOffset = Size.alignTo(Info.Alignment);
3140 
3141  assert(BaseOffset >= Size && "base offset already allocated");
3142 
3143  VBases.insert(std::make_pair(BaseDecl,
3144  ASTRecordLayout::VBaseInfo(BaseOffset, HasVtordisp)));
3145  Size = BaseOffset + BaseLayout.getNonVirtualSize();
3146  PreviousBaseLayout = &BaseLayout;
3147  }
3148 }
3149 
3150 void MicrosoftRecordLayoutBuilder::finalizeLayout(const RecordDecl *RD) {
3151  // Respect required alignment. Note that in 32-bit mode Required alignment
3152  // may be 0 and cause size not to be updated.
3153  DataSize = Size;
3154  if (!RequiredAlignment.isZero()) {
3155  Alignment = std::max(Alignment, RequiredAlignment);
3156  auto RoundingAlignment = Alignment;
3157  if (!MaxFieldAlignment.isZero())
3158  RoundingAlignment = std::min(RoundingAlignment, MaxFieldAlignment);
3159  RoundingAlignment = std::max(RoundingAlignment, RequiredAlignment);
3160  Size = Size.alignTo(RoundingAlignment);
3161  }
3162  if (Size.isZero()) {
3163  if (!recordUsesEBO(RD) || !cast<CXXRecordDecl>(RD)->isEmpty()) {
3164  EndsWithZeroSizedObject = true;
3165  LeadsWithZeroSizedBase = true;
3166  }
3167  // Zero-sized structures have size equal to their alignment if a
3168  // __declspec(align) came into play.
3169  if (RequiredAlignment >= MinEmptyStructSize)
3170  Size = Alignment;
3171  else
3172  Size = MinEmptyStructSize;
3173  }
3174 
3175  if (UseExternalLayout) {
3176  Size = Context.toCharUnitsFromBits(External.Size);
3177  if (External.Align)
3178  Alignment = Context.toCharUnitsFromBits(External.Align);
3179  }
3180 }
3181 
3182 // Recursively walks the non-virtual bases of a class and determines if any of
3183 // them are in the bases with overridden methods set.
3184 static bool
3185 RequiresVtordisp(const llvm::SmallPtrSetImpl<const CXXRecordDecl *> &
3186  BasesWithOverriddenMethods,
3187  const CXXRecordDecl *RD) {
3188  if (BasesWithOverriddenMethods.count(RD))
3189  return true;
3190  // If any of a virtual bases non-virtual bases (recursively) requires a
3191  // vtordisp than so does this virtual base.
3192  for (const CXXBaseSpecifier &Base : RD->bases())
3193  if (!Base.isVirtual() &&
3194  RequiresVtordisp(BasesWithOverriddenMethods,
3195  Base.getType()->getAsCXXRecordDecl()))
3196  return true;
3197  return false;
3198 }
3199 
3200 void MicrosoftRecordLayoutBuilder::computeVtorDispSet(
3201  llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtordispSet,
3202  const CXXRecordDecl *RD) const {
3203  // /vd2 or #pragma vtordisp(2): Always use vtordisps for virtual bases with
3204  // vftables.
3206  for (const CXXBaseSpecifier &Base : RD->vbases()) {
3207  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
3208  const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
3209  if (Layout.hasExtendableVFPtr())
3210  HasVtordispSet.insert(BaseDecl);
3211  }
3212  return;
3213  }
3214 
3215  // If any of our bases need a vtordisp for this type, so do we. Check our
3216  // direct bases for vtordisp requirements.
3217  for (const CXXBaseSpecifier &Base : RD->bases()) {
3218  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
3219  const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
3220  for (const auto &bi : Layout.getVBaseOffsetsMap())
3221  if (bi.second.hasVtorDisp())
3222  HasVtordispSet.insert(bi.first);
3223  }
3224  // We don't introduce any additional vtordisps if either:
3225  // * A user declared constructor or destructor aren't declared.
3226  // * #pragma vtordisp(0) or the /vd0 flag are in use.
3227  if ((!RD->hasUserDeclaredConstructor() && !RD->hasUserDeclaredDestructor()) ||
3229  return;
3230  // /vd1 or #pragma vtordisp(1): Try to guess based on whether we think it's
3231  // possible for a partially constructed object with virtual base overrides to
3232  // escape a non-trivial constructor.
3234  // Compute a set of base classes which define methods we override. A virtual
3235  // base in this set will require a vtordisp. A virtual base that transitively
3236  // contains one of these bases as a non-virtual base will also require a
3237  // vtordisp.
3239  llvm::SmallPtrSet<const CXXRecordDecl *, 2> BasesWithOverriddenMethods;
3240  // Seed the working set with our non-destructor, non-pure virtual methods.
3241  for (const CXXMethodDecl *MD : RD->methods())
3243  !isa<CXXDestructorDecl>(MD) && !MD->isPure())
3244  Work.insert(MD);
3245  while (!Work.empty()) {
3246  const CXXMethodDecl *MD = *Work.begin();
3247  auto MethodRange = MD->overridden_methods();
3248  // If a virtual method has no-overrides it lives in its parent's vtable.
3249  if (MethodRange.begin() == MethodRange.end())
3250  BasesWithOverriddenMethods.insert(MD->getParent());
3251  else
3252  Work.insert(MethodRange.begin(), MethodRange.end());
3253  // We've finished processing this element, remove it from the working set.
3254  Work.erase(MD);
3255  }
3256  // For each of our virtual bases, check if it is in the set of overridden
3257  // bases or if it transitively contains a non-virtual base that is.
3258  for (const CXXBaseSpecifier &Base : RD->vbases()) {
3259  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
3260  if (!HasVtordispSet.count(BaseDecl) &&
3261  RequiresVtordisp(BasesWithOverriddenMethods, BaseDecl))
3262  HasVtordispSet.insert(BaseDecl);
3263  }
3264 }
3265 
3266 /// getASTRecordLayout - Get or compute information about the layout of the
3267 /// specified record (struct/union/class), which indicates its size and field
3268 /// position information.
3269 const ASTRecordLayout &
3271  // These asserts test different things. A record has a definition
3272  // as soon as we begin to parse the definition. That definition is
3273  // not a complete definition (which is what isDefinition() tests)
3274  // until we *finish* parsing the definition.
3275 
3276  if (D->hasExternalLexicalStorage() && !D->getDefinition())
3277  getExternalSource()->CompleteType(const_cast<RecordDecl*>(D));
3278 
3279  D = D->getDefinition();
3280  assert(D && "Cannot get layout of forward declarations!");
3281  assert(!D->isInvalidDecl() && "Cannot get layout of invalid decl!");
3282  assert(D->isCompleteDefinition() && "Cannot layout type before complete!");
3283 
3284  // Look up this layout, if already laid out, return what we have.
3285  // Note that we can't save a reference to the entry because this function
3286  // is recursive.
3287  const ASTRecordLayout *Entry = ASTRecordLayouts[D];
3288  if (Entry) return *Entry;
3289 
3290  const ASTRecordLayout *NewEntry = nullptr;
3291 
3292  if (isMsLayout(*this)) {
3293  MicrosoftRecordLayoutBuilder Builder(*this);
3294  if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
3295  Builder.cxxLayout(RD);
3296  NewEntry = new (*this) ASTRecordLayout(
3297  *this, Builder.Size, Builder.Alignment, Builder.Alignment,
3298  Builder.Alignment, Builder.RequiredAlignment, Builder.HasOwnVFPtr,
3299  Builder.HasOwnVFPtr || Builder.PrimaryBase, Builder.VBPtrOffset,
3300  Builder.DataSize, Builder.FieldOffsets, Builder.NonVirtualSize,
3301  Builder.Alignment, Builder.Alignment, CharUnits::Zero(),
3302  Builder.PrimaryBase, false, Builder.SharedVBPtrBase,
3303  Builder.EndsWithZeroSizedObject, Builder.LeadsWithZeroSizedBase,
3304  Builder.Bases, Builder.VBases);
3305  } else {
3306  Builder.layout(D);
3307  NewEntry = new (*this) ASTRecordLayout(
3308  *this, Builder.Size, Builder.Alignment, Builder.Alignment,
3309  Builder.Alignment, Builder.RequiredAlignment, Builder.Size,
3310  Builder.FieldOffsets);
3311  }
3312  } else {
3313  if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
3314  EmptySubobjectMap EmptySubobjects(*this, RD);
3315  ItaniumRecordLayoutBuilder Builder(*this, &EmptySubobjects);
3316  Builder.Layout(RD);
3317 
3318  // In certain situations, we are allowed to lay out objects in the
3319  // tail-padding of base classes. This is ABI-dependent.
3320  // FIXME: this should be stored in the record layout.
3321  bool skipTailPadding =
3322  mustSkipTailPadding(getTargetInfo().getCXXABI(), RD);
3323 
3324  // FIXME: This should be done in FinalizeLayout.
3325  CharUnits DataSize =
3326  skipTailPadding ? Builder.getSize() : Builder.getDataSize();
3327  CharUnits NonVirtualSize =
3328  skipTailPadding ? DataSize : Builder.NonVirtualSize;
3329  NewEntry = new (*this) ASTRecordLayout(
3330  *this, Builder.getSize(), Builder.Alignment,
3331  Builder.PreferredAlignment, Builder.UnadjustedAlignment,
3332  /*RequiredAlignment : used by MS-ABI)*/
3333  Builder.Alignment, Builder.HasOwnVFPtr, RD->isDynamicClass(),
3334  CharUnits::fromQuantity(-1), DataSize, Builder.FieldOffsets,
3335  NonVirtualSize, Builder.NonVirtualAlignment,
3336  Builder.PreferredNVAlignment,
3337  EmptySubobjects.SizeOfLargestEmptySubobject, Builder.PrimaryBase,
3338  Builder.PrimaryBaseIsVirtual, nullptr, false, false, Builder.Bases,
3339  Builder.VBases);
3340  } else {
3341  ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3342  Builder.Layout(D);
3343 
3344  NewEntry = new (*this) ASTRecordLayout(
3345  *this, Builder.getSize(), Builder.Alignment,
3346  Builder.PreferredAlignment, Builder.UnadjustedAlignment,
3347  /*RequiredAlignment : used by MS-ABI)*/
3348  Builder.Alignment, Builder.getSize(), Builder.FieldOffsets);
3349  }
3350  }
3351 
3352  ASTRecordLayouts[D] = NewEntry;
3353 
3354  if (getLangOpts().DumpRecordLayouts) {
3355  llvm::outs() << "\n*** Dumping AST Record Layout\n";
3356  DumpRecordLayout(D, llvm::outs(), getLangOpts().DumpRecordLayoutsSimple);
3357  }
3358 
3359  return *NewEntry;
3360 }
3361 
3363  if (!getTargetInfo().getCXXABI().hasKeyFunctions())
3364  return nullptr;
3365 
3366  assert(RD->getDefinition() && "Cannot get key function for forward decl!");
3367  RD = RD->getDefinition();
3368 
3369  // Beware:
3370  // 1) computing the key function might trigger deserialization, which might
3371  // invalidate iterators into KeyFunctions
3372  // 2) 'get' on the LazyDeclPtr might also trigger deserialization and
3373  // invalidate the LazyDeclPtr within the map itself
3374  LazyDeclPtr Entry = KeyFunctions[RD];
3375  const Decl *Result =
3376  Entry ? Entry.get(getExternalSource()) : computeKeyFunction(*this, RD);
3377 
3378  // Store it back if it changed.
3379  if (Entry.isOffset() || Entry.isValid() != bool(Result))
3380  KeyFunctions[RD] = const_cast<Decl*>(Result);
3381 
3382  return cast_or_null<CXXMethodDecl>(Result);
3383 }
3384 
3386  assert(Method == Method->getFirstDecl() &&
3387  "not working with method declaration from class definition");
3388 
3389  // Look up the cache entry. Since we're working with the first
3390  // declaration, its parent must be the class definition, which is
3391  // the correct key for the KeyFunctions hash.
3392  const auto &Map = KeyFunctions;
3393  auto I = Map.find(Method->getParent());
3394 
3395  // If it's not cached, there's nothing to do.
3396  if (I == Map.end()) return;
3397 
3398  // If it is cached, check whether it's the target method, and if so,
3399  // remove it from the cache. Note, the call to 'get' might invalidate
3400  // the iterator and the LazyDeclPtr object within the map.
3401  LazyDeclPtr Ptr = I->second;
3402  if (Ptr.get(getExternalSource()) == Method) {
3403  // FIXME: remember that we did this for module / chained PCH state?
3404  KeyFunctions.erase(Method->getParent());
3405  }
3406 }
3407 
3408 static uint64_t getFieldOffset(const ASTContext &C, const FieldDecl *FD) {
3409  const ASTRecordLayout &Layout = C.getASTRecordLayout(FD->getParent());
3410  return Layout.getFieldOffset(FD->getFieldIndex());
3411 }
3412 
3414  uint64_t OffsetInBits;
3415  if (const FieldDecl *FD = dyn_cast<FieldDecl>(VD)) {
3416  OffsetInBits = ::getFieldOffset(*this, FD);
3417  } else {
3418  const IndirectFieldDecl *IFD = cast<IndirectFieldDecl>(VD);
3419 
3420  OffsetInBits = 0;
3421  for (const NamedDecl *ND : IFD->chain())
3422  OffsetInBits += ::getFieldOffset(*this, cast<FieldDecl>(ND));
3423  }
3424 
3425  return OffsetInBits;
3426 }
3427 
3429  const ObjCImplementationDecl *ID,
3430  const ObjCIvarDecl *Ivar) const {
3431  Ivar = Ivar->getCanonicalDecl();
3432  const ObjCInterfaceDecl *Container = Ivar->getContainingInterface();
3433 
3434  // FIXME: We should eliminate the need to have ObjCImplementationDecl passed
3435  // in here; it should never be necessary because that should be the lexical
3436  // decl context for the ivar.
3437 
3438  // If we know have an implementation (and the ivar is in it) then
3439  // look up in the implementation layout.
3440  const ASTRecordLayout *RL;
3441  if (ID && declaresSameEntity(ID->getClassInterface(), Container))
3443  else
3444  RL = &getASTObjCInterfaceLayout(Container);
3445 
3446  // Compute field index.
3447  //
3448  // FIXME: The index here is closely tied to how ASTContext::getObjCLayout is
3449  // implemented. This should be fixed to get the information from the layout
3450  // directly.
3451  unsigned Index = 0;
3452 
3453  for (const ObjCIvarDecl *IVD = Container->all_declared_ivar_begin();
3454  IVD; IVD = IVD->getNextIvar()) {
3455  if (Ivar == IVD)
3456  break;
3457  ++Index;
3458  }
3459  assert(Index < RL->getFieldCount() && "Ivar is not inside record layout!");
3460 
3461  return RL->getFieldOffset(Index);
3462 }
3463 
3464 /// getObjCLayout - Get or compute information about the layout of the
3465 /// given interface.
3466 ///
3467 /// \param Impl - If given, also include the layout of the interface's
3468 /// implementation. This may differ by including synthesized ivars.
3469 const ASTRecordLayout &
3470 ASTContext::getObjCLayout(const ObjCInterfaceDecl *D,
3471  const ObjCImplementationDecl *Impl) const {
3472  // Retrieve the definition
3473  if (D->hasExternalLexicalStorage() && !D->getDefinition())
3474  getExternalSource()->CompleteType(const_cast<ObjCInterfaceDecl*>(D));
3475  D = D->getDefinition();
3476  assert(D && !D->isInvalidDecl() && D->isThisDeclarationADefinition() &&
3477  "Invalid interface decl!");
3478 
3479  // Look up this layout, if already laid out, return what we have.
3480  const ObjCContainerDecl *Key =
3481  Impl ? (const ObjCContainerDecl*) Impl : (const ObjCContainerDecl*) D;
3482  if (const ASTRecordLayout *Entry = ObjCLayouts[Key])
3483  return *Entry;
3484 
3485  // Add in synthesized ivar count if laying out an implementation.
3486  if (Impl) {
3487  unsigned SynthCount = CountNonClassIvars(D);
3488  // If there aren't any synthesized ivars then reuse the interface
3489  // entry. Note we can't cache this because we simply free all
3490  // entries later; however we shouldn't look up implementations
3491  // frequently.
3492  if (SynthCount == 0)
3493  return getObjCLayout(D, nullptr);
3494  }
3495 
3496  ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3497  Builder.Layout(D);
3498 
3499  const ASTRecordLayout *NewEntry = new (*this) ASTRecordLayout(
3500  *this, Builder.getSize(), Builder.Alignment, Builder.PreferredAlignment,
3501  Builder.UnadjustedAlignment,
3502  /*RequiredAlignment : used by MS-ABI)*/
3503  Builder.Alignment, Builder.getDataSize(), Builder.FieldOffsets);
3504 
3505  ObjCLayouts[Key] = NewEntry;
3506 
3507  return *NewEntry;
3508 }
3509 
3510 static void PrintOffset(raw_ostream &OS,
3511  CharUnits Offset, unsigned IndentLevel) {
3512  OS << llvm::format("%10" PRId64 " | ", (int64_t)Offset.getQuantity());
3513  OS.indent(IndentLevel * 2);
3514 }
3515 
3516 static void PrintBitFieldOffset(raw_ostream &OS, CharUnits Offset,
3517  unsigned Begin, unsigned Width,
3518  unsigned IndentLevel) {
3519  llvm::SmallString<10> Buffer;
3520  {
3521  llvm::raw_svector_ostream BufferOS(Buffer);
3522  BufferOS << Offset.getQuantity() << ':';
3523  if (Width == 0) {
3524  BufferOS << '-';
3525  } else {
3526  BufferOS << Begin << '-' << (Begin + Width - 1);
3527  }
3528  }
3529 
3530  OS << llvm::right_justify(Buffer, 10) << " | ";
3531  OS.indent(IndentLevel * 2);
3532 }
3533 
3534 static void PrintIndentNoOffset(raw_ostream &OS, unsigned IndentLevel) {
3535  OS << " | ";
3536  OS.indent(IndentLevel * 2);
3537 }
3538 
3539 static void DumpRecordLayout(raw_ostream &OS, const RecordDecl *RD,
3540  const ASTContext &C,
3541  CharUnits Offset,
3542  unsigned IndentLevel,
3543  const char* Description,
3544  bool PrintSizeInfo,
3545  bool IncludeVirtualBases) {
3546  const ASTRecordLayout &Layout = C.getASTRecordLayout(RD);
3547  auto CXXRD = dyn_cast<CXXRecordDecl>(RD);
3548 
3549  PrintOffset(OS, Offset, IndentLevel);
3550  OS << C.getTypeDeclType(const_cast<RecordDecl *>(RD));
3551  if (Description)
3552  OS << ' ' << Description;
3553  if (CXXRD && CXXRD->isEmpty())
3554  OS << " (empty)";
3555  OS << '\n';
3556 
3557  IndentLevel++;
3558 
3559  // Dump bases.
3560  if (CXXRD) {
3561  const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
3562  bool HasOwnVFPtr = Layout.hasOwnVFPtr();
3563  bool HasOwnVBPtr = Layout.hasOwnVBPtr();
3564 
3565  // Vtable pointer.
3566  if (CXXRD->isDynamicClass() && !PrimaryBase && !isMsLayout(C)) {
3567  PrintOffset(OS, Offset, IndentLevel);
3568  OS << '(' << *RD << " vtable pointer)\n";
3569  } else if (HasOwnVFPtr) {
3570  PrintOffset(OS, Offset, IndentLevel);
3571  // vfptr (for Microsoft C++ ABI)
3572  OS << '(' << *RD << " vftable pointer)\n";
3573  }
3574 
3575  // Collect nvbases.
3577  for (const CXXBaseSpecifier &Base : CXXRD->bases()) {
3578  assert(!Base.getType()->isDependentType() &&
3579  "Cannot layout class with dependent bases.");
3580  if (!Base.isVirtual())
3581  Bases.push_back(Base.getType()->getAsCXXRecordDecl());
3582  }
3583 
3584  // Sort nvbases by offset.
3585  llvm::stable_sort(
3586  Bases, [&](const CXXRecordDecl *L, const CXXRecordDecl *R) {
3587  return Layout.getBaseClassOffset(L) < Layout.getBaseClassOffset(R);
3588  });
3589 
3590  // Dump (non-virtual) bases
3591  for (const CXXRecordDecl *Base : Bases) {
3592  CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base);
3593  DumpRecordLayout(OS, Base, C, BaseOffset, IndentLevel,
3594  Base == PrimaryBase ? "(primary base)" : "(base)",
3595  /*PrintSizeInfo=*/false,
3596  /*IncludeVirtualBases=*/false);
3597  }
3598 
3599  // vbptr (for Microsoft C++ ABI)
3600  if (HasOwnVBPtr) {
3601  PrintOffset(OS, Offset + Layout.getVBPtrOffset(), IndentLevel);
3602  OS << '(' << *RD << " vbtable pointer)\n";
3603  }
3604  }
3605 
3606  // Dump fields.
3607  uint64_t FieldNo = 0;
3608  for (RecordDecl::field_iterator I = RD->field_begin(),
3609  E = RD->field_end(); I != E; ++I, ++FieldNo) {
3610  const FieldDecl &Field = **I;
3611  uint64_t LocalFieldOffsetInBits = Layout.getFieldOffset(FieldNo);
3612  CharUnits FieldOffset =
3613  Offset + C.toCharUnitsFromBits(LocalFieldOffsetInBits);
3614 
3615  // Recursively dump fields of record type.
3616  if (auto RT = Field.getType()->getAs<RecordType>()) {
3617  DumpRecordLayout(OS, RT->getDecl(), C, FieldOffset, IndentLevel,
3618  Field.getName().data(),
3619  /*PrintSizeInfo=*/false,
3620  /*IncludeVirtualBases=*/true);
3621  continue;
3622  }
3623 
3624  if (Field.isBitField()) {
3625  uint64_t LocalFieldByteOffsetInBits = C.toBits(FieldOffset - Offset);
3626  unsigned Begin = LocalFieldOffsetInBits - LocalFieldByteOffsetInBits;
3627  unsigned Width = Field.getBitWidthValue(C);
3628  PrintBitFieldOffset(OS, FieldOffset, Begin, Width, IndentLevel);
3629  } else {
3630  PrintOffset(OS, FieldOffset, IndentLevel);
3631  }
3632  const QualType &FieldType = C.getLangOpts().DumpRecordLayoutsCanonical
3633  ? Field.getType().getCanonicalType()
3634  : Field.getType();
3635  OS << FieldType << ' ' << Field << '\n';
3636  }
3637 
3638  // Dump virtual bases.
3639  if (CXXRD && IncludeVirtualBases) {
3640  const ASTRecordLayout::VBaseOffsetsMapTy &VtorDisps =
3641  Layout.getVBaseOffsetsMap();
3642 
3643  for (const CXXBaseSpecifier &Base : CXXRD->vbases()) {
3644  assert(Base.isVirtual() && "Found non-virtual class!");
3645  const CXXRecordDecl *VBase = Base.getType()->getAsCXXRecordDecl();
3646 
3647  CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBase);
3648 
3649  if (VtorDisps.find(VBase)->second.hasVtorDisp()) {
3650  PrintOffset(OS, VBaseOffset - CharUnits::fromQuantity(4), IndentLevel);
3651  OS << "(vtordisp for vbase " << *VBase << ")\n";
3652  }
3653 
3654  DumpRecordLayout(OS, VBase, C, VBaseOffset, IndentLevel,
3655  VBase == Layout.getPrimaryBase() ?
3656  "(primary virtual base)" : "(virtual base)",
3657  /*PrintSizeInfo=*/false,
3658  /*IncludeVirtualBases=*/false);
3659  }
3660  }
3661 
3662  if (!PrintSizeInfo) return;
3663 
3664  PrintIndentNoOffset(OS, IndentLevel - 1);
3665  OS << "[sizeof=" << Layout.getSize().getQuantity();
3666  if (CXXRD && !isMsLayout(C))
3667  OS << ", dsize=" << Layout.getDataSize().getQuantity();
3668  OS << ", align=" << Layout.getAlignment().getQuantity();
3669  if (C.getTargetInfo().defaultsToAIXPowerAlignment())
3670  OS << ", preferredalign=" << Layout.getPreferredAlignment().getQuantity();
3671 
3672  if (CXXRD) {
3673  OS << ",\n";
3674  PrintIndentNoOffset(OS, IndentLevel - 1);
3675  OS << " nvsize=" << Layout.getNonVirtualSize().getQuantity();
3676  OS << ", nvalign=" << Layout.getNonVirtualAlignment().getQuantity();
3677  if (C.getTargetInfo().defaultsToAIXPowerAlignment())
3678  OS << ", preferrednvalign="
3679  << Layout.getPreferredNVAlignment().getQuantity();
3680  }
3681  OS << "]\n";
3682 }
3683 
3684 void ASTContext::DumpRecordLayout(const RecordDecl *RD, raw_ostream &OS,
3685  bool Simple) const {
3686  if (!Simple) {
3687  ::DumpRecordLayout(OS, RD, *this, CharUnits(), 0, nullptr,
3688  /*PrintSizeInfo*/ true,
3689  /*IncludeVirtualBases=*/true);
3690  return;
3691  }
3692 
3693  // The "simple" format is designed to be parsed by the
3694  // layout-override testing code. There shouldn't be any external
3695  // uses of this format --- when LLDB overrides a layout, it sets up
3696  // the data structures directly --- so feel free to adjust this as
3697  // you like as long as you also update the rudimentary parser for it
3698  // in libFrontend.
3699 
3700  const ASTRecordLayout &Info = getASTRecordLayout(RD);
3701  OS << "Type: " << getTypeDeclType(RD) << "\n";
3702  OS << "\nLayout: ";
3703  OS << "<ASTRecordLayout\n";
3704  OS << " Size:" << toBits(Info.getSize()) << "\n";
3705  if (!isMsLayout(*this))
3706  OS << " DataSize:" << toBits(Info.getDataSize()) << "\n";
3707  OS << " Alignment:" << toBits(Info.getAlignment()) << "\n";
3708  if (Target->defaultsToAIXPowerAlignment())
3709  OS << " PreferredAlignment:" << toBits(Info.getPreferredAlignment())
3710  << "\n";
3711  OS << " FieldOffsets: [";
3712  for (unsigned i = 0, e = Info.getFieldCount(); i != e; ++i) {
3713  if (i)
3714  OS << ", ";
3715  OS << Info.getFieldOffset(i);
3716  }
3717  OS << "]>\n";
3718 }
clang::BuiltinType
This class is used for builtin types like 'int'.
Definition: Type.h:2580
RequiresVtordisp
static bool RequiresVtordisp(const llvm::SmallPtrSetImpl< const CXXRecordDecl * > &BasesWithOverriddenMethods, const CXXRecordDecl *RD)
Definition: RecordLayoutBuilder.cpp:3185
clang::ObjCInterfaceDecl
Represents an ObjC class declaration.
Definition: DeclObjC.h:1150
clang::RecordDecl::hasFlexibleArrayMember
bool hasFlexibleArrayMember() const
Definition: Decl.h:3983
clang::ASTContext::getTypeSizeInChars
CharUnits getTypeSizeInChars(QualType T) const
Return the size of the specified (complete) type T, in characters.
Definition: ASTContext.cpp:2474
clang::FieldDecl::getBitWidthValue
unsigned getBitWidthValue(const ASTContext &Ctx) const
Definition: Decl.cpp:4281
clang::ASTContext::getASTObjCImplementationLayout
const ASTRecordLayout & getASTObjCImplementationLayout(const ObjCImplementationDecl *D) const
Get or compute information about the layout of the specified Objective-C implementation.
Definition: ASTContext.cpp:3002
clang::ASTRecordLayout::getPreferredAlignment
CharUnits getPreferredAlignment() const
getPreferredFieldAlignment - Get the record preferred alignment in characters.
Definition: RecordLayout.h:186
clang::Type::isRecordType
bool isRecordType() const
Definition: Type.h:6930
PrintIndentNoOffset
static void PrintIndentNoOffset(raw_ostream &OS, unsigned IndentLevel)
Definition: RecordLayoutBuilder.cpp:3534
max
__DEVICE__ int max(int __a, int __b)
Definition: __clang_cuda_math.h:196
clang::RecordDecl::field_begin
field_iterator field_begin() const
Definition: Decl.cpp:4718
clang::ASTContext::isAlignmentRequired
bool isAlignmentRequired(const Type *T) const
Determine if the alignment the type has was required using an alignment attribute.
Definition: ASTContext.cpp:1898
clang::ASTRecordLayout::getFieldOffset
uint64_t getFieldOffset(unsigned FieldNo) const
getFieldOffset - Get the offset of the given field index, in bits.
Definition: RecordLayout.h:200
clang::ASTRecordLayout::hasExtendableVFPtr
bool hasExtendableVFPtr() const
hasVFPtr - Does this class have a virtual function table pointer that can be extended by a derived cl...
Definition: RecordLayout.h:288
clang::ASTContext::getTypeDeclType
QualType getTypeDeclType(const TypeDecl *Decl, const TypeDecl *PrevDecl=nullptr) const
Return the unique reference to the type for the specified type declaration.
Definition: ASTContext.h:1582
computeKeyFunction
static const CXXMethodDecl * computeKeyFunction(ASTContext &Context, const CXXRecordDecl *RD)
Definition: RecordLayoutBuilder.cpp:2306
clang::DiagnosticBuilder
A little helper class used to produce diagnostics.
Definition: Diagnostic.h:1266
clang::DeclContext::specific_decl_iterator
specific_decl_iterator - Iterates over a subrange of declarations stored in a DeclContext,...
Definition: DeclBase.h:2187
clang::ASTContext::getCharWidth
uint64_t getCharWidth() const
Return the size of the character type, in bits.
Definition: ASTContext.h:2302
clang::ASTContext::UnsignedShortTy
CanQualType UnsignedShortTy
Definition: ASTContext.h:1116
clang::index::SymbolKind::Class
@ Class
clang::DeclContext::hasExternalLexicalStorage
bool hasExternalLexicalStorage() const
Whether this DeclContext has external storage containing additional declarations that are lexically i...
Definition: DeclBase.h:2482
roundUpSizeToCharAlignment
static uint64_t roundUpSizeToCharAlignment(uint64_t Size, const ASTContext &Context)
Definition: RecordLayoutBuilder.cpp:1461
clang::RecordDecl::mayInsertExtraPadding
bool mayInsertExtraPadding(bool EmitRemark=false) const
Whether we are allowed to insert extra padding between fields.
Definition: Decl.cpp:4778
clang::ASTContext::CountNonClassIvars
unsigned CountNonClassIvars(const ObjCInterfaceDecl *OI) const
Definition: ASTContext.cpp:2865
clang::ObjCIvarDecl::getNextIvar
ObjCIvarDecl * getNextIvar()
Definition: DeclObjC.h:1959
mustSkipTailPadding
static bool mustSkipTailPadding(TargetCXXABI ABI, const CXXRecordDecl *RD)
Does the target C++ ABI require us to skip over the tail-padding of the given class (considering it a...
Definition: RecordLayoutBuilder.cpp:2395
clang::Decl::hasAttr
bool hasAttr() const
Definition: DeclBase.h:557
clang::ObjCImplementationDecl
ObjCImplementationDecl - Represents a class definition - this is where method definitions are specifi...
Definition: DeclObjC.h:2548
clang::ConstantArrayType
Represents the canonical version of C arrays with a specified constant size.
Definition: Type.h:3018
clang::ObjCIvarDecl::getCanonicalDecl
ObjCIvarDecl * getCanonicalDecl() override
Retrieves the canonical declaration of this field.
Definition: DeclObjC.h:1963
Diag
static DiagnosticBuilder Diag(DiagnosticsEngine *Diags, const LangOptions &Features, FullSourceLoc TokLoc, const char *TokBegin, const char *TokRangeBegin, const char *TokRangeEnd, unsigned DiagID)
Produce a diagnostic highlighting some portion of a literal.
Definition: LiteralSupport.cpp:79
clang::NamedDecl::isExternallyVisible
bool isExternallyVisible() const
Definition: Decl.h:405
llvm::SmallVector
Definition: LLVM.h:38
clang::ASTContext::operator=
ASTContext & operator=(const ASTContext &)=delete
clang::SourceLocation
Encodes a location in the source.
Definition: SourceLocation.h:86
isMsLayout
static bool isMsLayout(const ASTContext &Context)
Definition: RecordLayoutBuilder.cpp:2434
clang::TargetCXXABI::isMicrosoft
bool isMicrosoft() const
Is this ABI an MSVC-compatible ABI?
Definition: TargetCXXABI.h:138
clang::TTK_Struct
@ TTK_Struct
The "struct" keyword.
Definition: Type.h:5468
clang::NamedDecl
This represents a decl that may have a name.
Definition: Decl.h:247
clang::RecordDecl::field_iterator
specific_decl_iterator< FieldDecl > field_iterator
Definition: Decl.h:4152
TargetInfo.h
clang::MultiVersionKind::Target
@ Target
PrintBitFieldOffset
static void PrintBitFieldOffset(raw_ostream &OS, CharUnits Offset, unsigned Begin, unsigned Width, unsigned IndentLevel)
Definition: RecordLayoutBuilder.cpp:3516
CXXInheritance.h
clang::TargetInfo::useLeadingZeroLengthBitfield
bool useLeadingZeroLengthBitfield() const
Check whether zero length bitfield alignment is respected if they are leading members.
Definition: TargetInfo.h:854
clang::CXXRecordDecl::getDefinition
CXXRecordDecl * getDefinition() const
Definition: DeclCXX.h:543
clang::QualType
A (possibly-)qualified type.
Definition: Type.h:731
clang::ASTContext::getTargetAddressSpace
unsigned getTargetAddressSpace(QualType T) const
Definition: ASTContext.cpp:12140
Attr.h
clang::ASTRecordLayout::getBaseClassOffset
CharUnits getBaseClassOffset(const CXXRecordDecl *Base) const
getBaseClassOffset - Get the offset, in chars, for the given base class.
Definition: RecordLayout.h:249
clang::FieldDecl
Represents a member of a struct/union/class.
Definition: Decl.h:2878
clang::ASTContext::getBaseElementType
QualType getBaseElementType(const ArrayType *VAT) const
Return the innermost element type of an array type.
Definition: ASTContext.cpp:6898
clang::TargetInfo::getCXXABI
TargetCXXABI getCXXABI() const
Get the C++ ABI currently in use.
Definition: TargetInfo.h:1250
getCharWidth
static unsigned getCharWidth(tok::TokenKind kind, const TargetInfo &Target)
Definition: LiteralSupport.cpp:40
clang::Redeclarable::getFirstDecl
decl_type * getFirstDecl()
Return the first declaration of this declaration or itself if this is the only declaration.
Definition: Redeclarable.h:216
DeclCXX.h
clang::TypeInfo::Width
uint64_t Width
Definition: ASTContext.h:180
clang::ASTRecordLayout::getNonVirtualAlignment
CharUnits getNonVirtualAlignment() const
getNonVirtualAlignment - Get the non-virtual alignment (in chars) of an object, which is the alignmen...
Definition: RecordLayout.h:218
clang::ASTRecordLayout::getSizeOfLargestEmptySubobject
CharUnits getSizeOfLargestEmptySubobject() const
Definition: RecordLayout.h:268
clang::TargetInfo::useBitFieldTypeAlignment
bool useBitFieldTypeAlignment() const
Check whether the alignment of bit-field types is respected when laying out structures.
Definition: TargetInfo.h:842
clang::ASTRecordLayout::getSize
CharUnits getSize() const
getSize - Get the record size in characters.
Definition: RecordLayout.h:193
clang::TargetInfo::getCharWidth
unsigned getCharWidth() const
Definition: TargetInfo.h:448
clang::RecordDecl::getDefinition
RecordDecl * getDefinition() const
Returns the RecordDecl that actually defines this struct/union/class.
Definition: Decl.h:4140
llvm::SmallPtrSet
Definition: ASTContext.h:82
clang::TargetCXXABI::getTailPaddingUseRules
TailPaddingUseRules getTailPaddingUseRules() const
Definition: TargetCXXABI.h:282
clang::CXXRecordDecl::hasUserDeclaredConstructor
bool hasUserDeclaredConstructor() const
Determine whether this class has any user-declared constructors.
Definition: DeclCXX.h:769
clang::AlignRequirementKind
AlignRequirementKind
Definition: ASTContext.h:165
clang::ASTRecordLayout::getPrimaryBase
const CXXRecordDecl * getPrimaryBase() const
getPrimaryBase - Get the primary base for this record.
Definition: RecordLayout.h:234
clang::Decl::getAttr
T * getAttr() const
Definition: DeclBase.h:553
clang::FunctionDecl::isInlineSpecified
bool isInlineSpecified() const
Determine whether the "inline" keyword was specified for this function.
Definition: Decl.h:2627
clang::ASTContext::getCurrentKeyFunction
const CXXMethodDecl * getCurrentKeyFunction(const CXXRecordDecl *RD)
Get our current best idea for the key function of the given record decl, or nullptr if there isn't on...
Definition: RecordLayoutBuilder.cpp:3362
clang::MSVtorDispMode::ForVFTable
@ ForVFTable
clang::TTK_Interface
@ TTK_Interface
The "__interface" keyword.
Definition: Type.h:5471
clang::ASTContext::toBits
int64_t toBits(CharUnits CharSize) const
Convert a size in characters to a size in bits.
Definition: ASTContext.cpp:2468
End
SourceLocation End
Definition: USRLocFinder.cpp:167
clang::ASTRecordLayout::getPreferredNVAlignment
CharUnits getPreferredNVAlignment() const
getPreferredNVAlignment - Get the preferred non-virtual alignment (in chars) of an object,...
Definition: RecordLayout.h:227
clang::Type
The base class of the type hierarchy.
Definition: Type.h:1559
getPaddingDiagFromTagKind
static unsigned getPaddingDiagFromTagKind(TagTypeKind Tag)
Get diagnostic select index for tag kind for field padding diagnostic message.
Definition: RecordLayoutBuilder.cpp:2255
Decl.h
DeclObjC.h
Offset
unsigned Offset
Definition: Format.cpp:2590
clang::ObjCIvarDecl::getContainingInterface
ObjCInterfaceDecl * getContainingInterface()
Return the class interface that this ivar is logically contained in; this is either the interface whe...
Definition: DeclObjC.cpp:1846
uint64_t
unsigned long uint64_t
Definition: hlsl_basic_types.h:24
clang::ObjCInterfaceDecl::isThisDeclarationADefinition
bool isThisDeclarationADefinition() const
Determine whether this particular declaration of this class is actually also a definition.
Definition: DeclObjC.h:1508
clang::ASTContext::getTypeAlignInChars
CharUnits getTypeAlignInChars(QualType T) const
Return the ABI-specified alignment of a (complete) type T, in characters.
Definition: ASTContext.cpp:2483
clang::TypeInfo
Definition: ASTContext.h:179
clang::LazyOffsetPtr< Decl, uint32_t, &ExternalASTSource::GetExternalDecl >
clang::ASTContext::setNonKeyFunction
void setNonKeyFunction(const CXXMethodDecl *method)
Observe that the given method cannot be a key function.
Definition: RecordLayoutBuilder.cpp:3385
clang::TSK_ExplicitInstantiationDeclaration
@ TSK_ExplicitInstantiationDeclaration
This template specialization was instantiated from a template due to an explicit instantiation declar...
Definition: Specifiers.h:188
getFieldOffset
static uint64_t getFieldOffset(const ASTContext &C, const FieldDecl *FD)
Definition: RecordLayoutBuilder.cpp:3408
clang::ASTContext::getExternalSource
ExternalASTSource * getExternalSource() const
Retrieve a pointer to the external AST source associated with this AST context, if any.
Definition: ASTContext.h:1193
clang::TargetInfo::useZeroLengthBitfieldAlignment
bool useZeroLengthBitfieldAlignment() const
Check whether zero length bitfields should force alignment of the next member.
Definition: TargetInfo.h:848
min
__DEVICE__ int min(int __a, int __b)
Definition: __clang_cuda_math.h:197
clang::RecordType
A helper class that allows the use of isa/cast/dyncast to detect TagType objects of structs/unions/cl...
Definition: Type.h:4723
clang::CXXMethodDecl::overridden_methods
overridden_method_range overridden_methods() const
Definition: DeclCXX.cpp:2452
clang::TargetCXXABI::canKeyFunctionBeInline
bool canKeyFunctionBeInline() const
Can an out-of-line inline function serve as a key function?
Definition: TargetCXXABI.h:240
clang::ASTContext::getAsConstantArrayType
const ConstantArrayType * getAsConstantArrayType(QualType T) const
Definition: ASTContext.h:2714
clang::CXXRecordDecl::methods
method_range methods() const
Definition: DeclCXX.h:639
clang::TagTypeKind
TagTypeKind
The kind of a tag type.
Definition: Type.h:5466
clang::CharUnits::fromQuantity
static CharUnits fromQuantity(QuantityType Quantity)
fromQuantity - Construct a CharUnits quantity from a raw integer type.
Definition: CharUnits.h:63
clang::CXXRecordDecl::getMSVtorDispMode
MSVtorDispMode getMSVtorDispMode() const
Controls when vtordisps will be emitted if this record is used as a virtual base.
Definition: MicrosoftCXXABI.cpp:246
clang::ASTContext
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:209
clang::CXXRecordDecl::isCXX11StandardLayout
bool isCXX11StandardLayout() const
Determine whether this class was standard-layout per C++11 [class]p7, specifically using the C++11 ru...
Definition: DeclCXX.h:1186
clang::TargetInfo::getPointerAlign
uint64_t getPointerAlign(unsigned AddrSpace) const
Definition: TargetInfo.h:429
clang::ASTContext::getConstantArrayElementCount
uint64_t getConstantArrayElementCount(const ConstantArrayType *CA) const
Return number of constant array elements.
Definition: ASTContext.cpp:6918
clang::Type::getAs
const T * getAs() const
Member-template getAs<specific type>'.
Definition: Type.h:7335
clang::Decl::isInvalidDecl
bool isInvalidDecl() const
Definition: DeclBase.h:568
clang::TypeInfo::isAlignRequired
bool isAlignRequired()
Definition: ASTContext.h:188
clang::ASTRecordLayout::getNonVirtualSize
CharUnits getNonVirtualSize() const
getNonVirtualSize - Get the non-virtual size (in chars) of an object, which is the size of the object...
Definition: RecordLayout.h:210
clang::ASTRecordLayout::VBaseInfo
Definition: RecordLayout.h:40
clang::CharUnits::One
static CharUnits One()
One - Construct a CharUnits quantity of one.
Definition: CharUnits.h:58
clang::ASTContext::getTypeSize
uint64_t getTypeSize(QualType T) const
Return the size of the specified (complete) type T, in bits.
Definition: ASTContext.h:2298
clang::TargetCXXABI::UseTailPaddingUnlessPOD11
@ UseTailPaddingUnlessPOD11
Only allocate objects in the tail padding of a base class if the base class is not POD according to t...
Definition: TargetCXXABI.h:280
clang::CXXRecordDecl::isPOD
bool isPOD() const
Whether this class is a POD-type (C++ [class]p4)
Definition: DeclCXX.h:1135
Expr.h
llvm::SmallString
Definition: LLVM.h:37
ASTContext.h
clang::AlignRequirementKind::RequiredByTypedef
@ RequiredByTypedef
The alignment comes from an alignment attribute on a typedef.
clang::interp::Zero
bool Zero(InterpState &S, CodePtr OpPC)
Definition: Interp.h:854
clang::ASTRecordLayout::getVBPtrOffset
CharUnits getVBPtrOffset() const
getVBPtrOffset - Get the offset for virtual base table pointer.
Definition: RecordLayout.h:324
clang::ASTRecordLayout::getRequiredAlignment
CharUnits getRequiredAlignment() const
Definition: RecordLayout.h:311
clang::Type::getPointeeType
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee.
Definition: Type.cpp:625
clang::TSK_ExplicitInstantiationDefinition
@ TSK_ExplicitInstantiationDefinition
This template specialization was instantiated from a template due to an explicit instantiation defini...
Definition: Specifiers.h:192
clang::TTK_Class
@ TTK_Class
The "class" keyword.
Definition: Type.h:5477
clang::CXXIndirectPrimaryBaseSet
A set of all the primary bases for a class.
Definition: CXXInheritance.h:361
clang::Type::getAsCXXRecordDecl
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1759
clang::TagDecl::isUnion
bool isUnion() const
Definition: Decl.h:3577
clang::CXXRecordDecl::bases
base_class_range bases()
Definition: DeclCXX.h:597
clang::CharUnits::Zero
static CharUnits Zero()
Zero - Construct a CharUnits quantity of zero.
Definition: CharUnits.h:53
clang::ASTContext::isNearlyEmpty
bool isNearlyEmpty(const CXXRecordDecl *RD) const
Definition: ASTContext.cpp:11776
Base
clang::ASTContext::DumpRecordLayout
void DumpRecordLayout(const RecordDecl *RD, raw_ostream &OS, bool Simple=false) const
Definition: RecordLayoutBuilder.cpp:3684
clang::TagDecl::isCompleteDefinition
bool isCompleteDefinition() const
Return true if this decl has its body fully specified.
Definition: Decl.h:3476
ASTDiagnostic.h
clang::TargetCXXABI::UseTailPaddingUnlessPOD03
@ UseTailPaddingUnlessPOD03
Only allocate objects in the tail padding of a base class if the base class is not POD according to t...
Definition: TargetCXXABI.h:276
clang::CXXRecordDecl::vbases
base_class_range vbases()
Definition: DeclCXX.h:614
clang::ASTRecordLayout::leadsWithZeroSizedBase
bool leadsWithZeroSizedBase() const
Definition: RecordLayout.h:317
clang::LazyOffsetPtr::isValid
bool isValid() const
Whether this pointer is non-NULL.
Definition: ExternalASTSource.h:364
clang::ASTContext::UnsignedLongLongTy
CanQualType UnsignedLongLongTy
Definition: ASTContext.h:1117
clang::ASTRecordLayout::isPrimaryBaseVirtual
bool isPrimaryBaseVirtual() const
isPrimaryBaseVirtual - Get whether the primary base for this record is virtual or not.
Definition: RecordLayout.h:242
clang::ASTRecordLayout::getVBaseClassOffset
CharUnits getVBaseClassOffset(const CXXRecordDecl *VBase) const
getVBaseClassOffset - Get the offset, in chars, for the given base class.
Definition: RecordLayout.h:259
clang::ASTRecordLayout::getDataSize
CharUnits getDataSize() const
getDataSize() - Get the record data size, which is the record size without tail padding,...
Definition: RecordLayout.h:206
DumpRecordLayout
static void DumpRecordLayout(raw_ostream &OS, const RecordDecl *RD, const ASTContext &C, CharUnits Offset, unsigned IndentLevel, const char *Description, bool PrintSizeInfo, bool IncludeVirtualBases)
Definition: RecordLayoutBuilder.cpp:3539
clang::MSVtorDispMode::Never
@ Never
clang::CXXRecordDecl::isEmpty
bool isEmpty() const
Determine whether this is an empty class in the sense of (C++11 [meta.unary.prop]).
Definition: DeclCXX.h:1150
clang::ASTContext::UnsignedCharTy
CanQualType UnsignedCharTy
Definition: ASTContext.h:1116
clang::TargetInfo::defaultsToAIXPowerAlignment
virtual bool defaultsToAIXPowerAlignment() const
Whether target defaults to the power alignment rules of AIX.
Definition: TargetInfo.h:1567
clang::FieldDecl::getFieldIndex
unsigned getFieldIndex() const
Returns the index of this field within its record, as appropriate for passing to ASTRecordLayout::get...
Definition: Decl.cpp:4324
clang::TargetInfo::getTriple
const llvm::Triple & getTriple() const
Returns the target triple of the primary target.
Definition: TargetInfo.h:1177
clang::ASTContext::UnsignedLongTy
CanQualType UnsignedLongTy
Definition: ASTContext.h:1116
clang::ASTRecordLayout
ASTRecordLayout - This class contains layout information for one RecordDecl, which is a struct/union/...
Definition: RecordLayout.h:38
clang::LazyOffsetPtr::isOffset
bool isOffset() const
Whether this pointer is currently stored as an offset.
Definition: ExternalASTSource.h:367
clang::CXXRecordDecl
Represents a C++ struct/union/class.
Definition: DeclCXX.h:254
clang::TemplateSpecializationKind
TemplateSpecializationKind
Describes the kind of template specialization that a particular template specialization declaration r...
Definition: Specifiers.h:174
clang::MSVtorDispMode::ForVBaseOverride
@ ForVBaseOverride
clang::ASTContext::UnsignedIntTy
CanQualType UnsignedIntTy
Definition: ASTContext.h:1116
clang::FieldDecl::isBitField
bool isBitField() const
Determines whether this field is a bitfield.
Definition: Decl.h:2956
VTableBuilder.h
clang::syntax::NodeRole::Size
@ Size
clang::ExternalASTSource::CompleteType
virtual void CompleteType(TagDecl *Tag)
Gives the external AST source an opportunity to complete an incomplete type.
Definition: ExternalASTSource.cpp:49
false
#define false
Definition: stdbool.h:22
clang::ASTRecordLayout::getVBaseOffsetsMap
const VBaseOffsetsMapTy & getVBaseOffsetsMap() const
Definition: RecordLayout.h:334
clang::CXXRecordDecl::getNumVBases
unsigned getNumVBases() const
Retrieves the number of virtual base classes of this class.
Definition: DeclCXX.h:612
clang::ASTRecordLayout::endsWithZeroSizedObject
bool endsWithZeroSizedObject() const
Definition: RecordLayout.h:313
clang::NamedDecl::getIdentifier
IdentifierInfo * getIdentifier() const
Get the identifier that names this declaration, if there is one.
Definition: Decl.h:268
clang::ValueDecl
Represent the declaration of a variable (in which case it is an lvalue) a function (in which case it ...
Definition: Decl.h:674
clang::ComplexType
Complex values, per C99 6.2.5p11.
Definition: Type.h:2676
clang::CharUnits::isZero
bool isZero() const
isZero - Test whether the quantity equals zero.
Definition: CharUnits.h:116
clang::ASTRecordLayout::hasOwnVFPtr
bool hasOwnVFPtr() const
hasOwnVFPtr - Does this class provide its own virtual-function table pointer, rather than inheriting ...
Definition: RecordLayout.h:280
clang::ASTContext::getFieldOffset
uint64_t getFieldOffset(const ValueDecl *FD) const
Get the offset of a FieldDecl or IndirectFieldDecl, in bits.
Definition: RecordLayoutBuilder.cpp:3413
clang::ASTRecordLayout::VBaseOffsetsMapTy
llvm::DenseMap< const CXXRecordDecl *, VBaseInfo > VBaseOffsetsMapTy
Definition: RecordLayout.h:59
clang::Type::isIncompleteArrayType
bool isIncompleteArrayType() const
Definition: Type.h:6914
clang::RecordDecl::fields
field_range fields() const
Definition: Decl.h:4155
Begin
SourceLocation Begin
Definition: USRLocFinder.cpp:165
clang::Decl
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:83
clang::ASTRecordLayout::hasOwnVBPtr
bool hasOwnVBPtr() const
hasOwnVBPtr - Does this class provide its own virtual-base table pointer, rather than inheriting one ...
Definition: RecordLayout.h:300
clang::CharUnits::alignTo
CharUnits alignTo(const CharUnits &Align) const
alignTo - Returns the next integer (mod 2**64) that is greater than or equal to this quantity and is ...
Definition: CharUnits.h:194
clang::ObjCInterfaceDecl::getSuperClass
ObjCInterfaceDecl * getSuperClass() const
Definition: DeclObjC.cpp:351
clang::TargetInfo::getZeroLengthBitfieldBoundary
unsigned getZeroLengthBitfieldBoundary() const
Get the fixed alignment value in bits for a member that follows a zero length bitfield.
Definition: TargetInfo.h:860
clang::TargetCXXABI::AlwaysUseTailPadding
@ AlwaysUseTailPadding
The tail-padding of a base class is always theoretically available, even if it's POD.
Definition: TargetCXXABI.h:272
clang::TargetInfo::hasPS4DLLImportExport
virtual bool hasPS4DLLImportExport() const
Definition: TargetInfo.h:1219
clang::ASTContext::getTargetInfo
const TargetInfo & getTargetInfo() const
Definition: ASTContext.h:772
clang::RecordDecl::field_end
field_iterator field_end() const
Definition: Decl.h:4158
PrintOffset
static void PrintOffset(raw_ostream &OS, CharUnits Offset, unsigned IndentLevel)
Definition: RecordLayoutBuilder.cpp:3510
clang::TargetInfo::useExplicitBitFieldAlignment
bool useExplicitBitFieldAlignment() const
Check whether explicit bitfield alignment attributes should be.
Definition: TargetInfo.h:870
int64_t
long int64_t
Definition: hlsl_basic_types.h:25
clang::AlignRequirementKind::RequiredByRecord
@ RequiredByRecord
The alignment comes from an alignment attribute on a record type.
clang::LazyOffsetPtr::get
T * get(ExternalASTSource *Source) const
Retrieve the pointer to the AST node that this lazy pointer points to.
Definition: ExternalASTSource.h:374
clang::AlignRequirementKind::None
@ None
The alignment was not explicit in code.
clang::Type::getBaseElementTypeUnsafe
const Type * getBaseElementTypeUnsafe() const
Get the base element type of this type, potentially discarding type qualifiers.
Definition: Type.h:7285
clang::Builtin::ID
ID
Definition: Builtins.h:52
clang::SourceLocation::isInvalid
bool isInvalid() const
Definition: SourceLocation.h:111
clang::FieldDecl::getParent
const RecordDecl * getParent() const
Returns the parent of this field declaration, which is the struct in which this field is defined.
Definition: Decl.h:3070
clang::CXXRecordDecl::getTemplateSpecializationKind
TemplateSpecializationKind getTemplateSpecializationKind() const
Determine whether this particular class is a specialization or instantiation of a class template or m...
Definition: DeclCXX.cpp:1836
clang
Definition: CalledOnceCheck.h:17
clang::LangOptions::MSVC2015
@ MSVC2015
Definition: LangOptions.h:145
clang::IndirectFieldDecl
Represents a field injected from an anonymous union/struct into the parent scope.
Definition: Decl.h:3132
clang::DeclContext::lookup
lookup_result lookup(DeclarationName Name) const
lookup - Find the declarations (if any) with the given Name in this context.
Definition: DeclBase.cpp:1668
clang::TypeInfo::Align
unsigned Align
Definition: ASTContext.h:181
clang::ASTContext::toCharUnitsFromBits
CharUnits toCharUnitsFromBits(int64_t BitSize) const
Convert a size in bits to a size in characters.
Definition: ASTContext.cpp:2463
clang::TargetInfo::getPointerWidth
uint64_t getPointerWidth(unsigned AddrSpace) const
Return the width of pointers on this target, for the specified address space.
Definition: TargetInfo.h:426
clang::ObjCIvarDecl
ObjCIvarDecl - Represents an ObjC instance variable.
Definition: DeclObjC.h:1923
clang::CXXBaseSpecifier
Represents a base class of a C++ class.
Definition: DeclCXX.h:146
clang::ASTRecordLayout::hasVBPtr
bool hasVBPtr() const
hasVBPtr - Does this class have a virtual function table pointer.
Definition: RecordLayout.h:306
clang::ASTRecordLayout::getFieldCount
unsigned getFieldCount() const
getFieldCount - Get the number of fields in the layout.
Definition: RecordLayout.h:196
clang::RecordDecl::isMsStruct
bool isMsStruct(const ASTContext &C) const
Get whether or not this is an ms_struct which can be turned on with an attribute, pragma,...
Definition: Decl.cpp:4742
clang::ASTRecordLayout::getAlignment
CharUnits getAlignment() const
getAlignment - Get the record alignment in characters.
Definition: RecordLayout.h:182
clang::TagDecl::getTagKind
TagKind getTagKind() const
Definition: Decl.h:3568
clang::Type::getUnqualifiedDesugaredType
const Type * getUnqualifiedDesugaredType() const
Return the specified type with any "sugar" removed from the type, removing any typedefs,...
Definition: Type.cpp:539
clang::TargetInfo::getCharAlign
unsigned getCharAlign() const
Definition: TargetInfo.h:449
clang::ObjCInterfaceDecl::all_declared_ivar_begin
ObjCIvarDecl * all_declared_ivar_begin()
all_declared_ivar_begin - return first ivar declared in this class, its extensions and its implementa...
Definition: DeclObjC.cpp:1643
clang::ASTContext::lookupFieldBitOffset
uint64_t lookupFieldBitOffset(const ObjCInterfaceDecl *OID, const ObjCImplementationDecl *ID, const ObjCIvarDecl *Ivar) const
Get the offset of an ObjCIvarDecl in bits.
Definition: RecordLayoutBuilder.cpp:3428
clang::ASTContext::getASTRecordLayout
const ASTRecordLayout & getASTRecordLayout(const RecordDecl *D) const
Get or compute information about the layout of the specified record (struct/union/class) D,...
Definition: RecordLayoutBuilder.cpp:3270
clang::ObjCContainerDecl
ObjCContainerDecl - Represents a container for method declarations.
Definition: DeclObjC.h:944
clang::CXXRecordDecl::isTrivial
bool isTrivial() const
Determine whether this class is considered trivial.
Definition: DeclCXX.h:1390
clang::CXXRecordDecl::isDynamicClass
bool isDynamicClass() const
Definition: DeclCXX.h:563
clang::RecordType::getDecl
RecordDecl * getDecl() const
Definition: Type.h:4733
clang::CXXRecordDecl::isPolymorphic
bool isPolymorphic() const
Whether this class is polymorphic (C++ [class.virtual]), which means that the class contains or inher...
Definition: DeclCXX.h:1171
clang::ReferenceType
Base for LValueReferenceType and RValueReferenceType.
Definition: Type.h:2840
clang::CharUnits
CharUnits - This is an opaque type for sizes expressed in character units.
Definition: CharUnits.h:38
clang::ASTContext::getTypeInfoInChars
TypeInfoChars getTypeInfoInChars(const Type *T) const
Definition: ASTContext.cpp:1886
recordUsesEBO
static bool recordUsesEBO(const RecordDecl *RD)
Definition: RecordLayoutBuilder.cpp:2881
clang::LangOptions::ClangABI::Ver14
@ Ver14
Attempt to be ABI-compatible with code generated by Clang 14.0.x.
clang::CXXRecordDecl::hasUserDeclaredDestructor
bool hasUserDeclaredDestructor() const
Determine whether this class has a user-declared destructor.
Definition: DeclCXX.h:983
clang::ValueDecl::getType
QualType getType() const
Definition: Decl.h:685
clang::CXXRecordDecl::getIndirectPrimaryBases
void getIndirectPrimaryBases(CXXIndirectPrimaryBaseSet &Bases) const
Get the indirect primary bases for this class.
Definition: CXXInheritance.cpp:702
clang::ASTContext::getASTObjCInterfaceLayout
const ASTRecordLayout & getASTObjCInterfaceLayout(const ObjCInterfaceDecl *D) const
Get or compute information about the layout of the specified Objective-C interface.
Definition: ASTContext.cpp:2997
clang::IndirectFieldDecl::chain
ArrayRef< NamedDecl * > chain() const
Definition: Decl.h:3154
AIX
clang::driver::toolchains::AIX AIX
Definition: AIX.cpp:18
clang::ASTContext::getTypeInfo
TypeInfo getTypeInfo(const Type *T) const
Get the size and alignment of the specified complete type in bits.
Definition: ASTContext.cpp:1931
isAIXLayout
static bool isAIXLayout(const ASTContext &Context)
Definition: RecordLayoutBuilder.cpp:1533
clang::ExternalASTSource
Abstract interface for external sources of AST nodes.
Definition: ExternalASTSource.h:60
clang::TSK_ImplicitInstantiation
@ TSK_ImplicitInstantiation
This template specialization was implicitly instantiated from a template.
Definition: Specifiers.h:180
clang::Decl::getLocation
SourceLocation getLocation() const
Definition: DeclBase.h:432
clang::Decl::getMaxAlignment
unsigned getMaxAlignment() const
getMaxAlignment - return the maximum alignment specified by attributes on this decl,...
Definition: DeclBase.cpp:429
clang::FunctionDecl
Represents a function declaration or definition.
Definition: Decl.h:1877
clang::RecordDecl
Represents a struct/union/class.
Definition: Decl.h:3929
clang::TargetCXXABI
The basic abstraction for the target C++ ABI.
Definition: TargetCXXABI.h:28
clang::LangOptions::ClangABI::Ver6
@ Ver6
Attempt to be ABI-compatible with code generated by Clang 6.0.x (SVN r321711).
clang::VirtualBaseInfo
All virtual base related information about a given record decl.
Definition: VTableBuilder.h:500
clang::VTableContextBase::hasVtableSlot
static bool hasVtableSlot(const CXXMethodDecl *MD)
Determine whether this function should be assigned a vtable slot.
Definition: VTableBuilder.cpp:2260
clang::ASTContext::getLangOpts
const LangOptions & getLangOpts() const
Definition: ASTContext.h:790
clang::CharUnits::getQuantity
QuantityType getQuantity() const
getQuantity - Get the raw integer representation of this quantity.
Definition: CharUnits.h:179
clang::ASTContext::getDiagnostics
DiagnosticsEngine & getDiagnostics() const
Definition: ASTContext.cpp:1502
RecordLayout.h
clang::declaresSameEntity
bool declaresSameEntity(const Decl *D1, const Decl *D2)
Determine whether two declarations declare the same entity.
Definition: DeclBase.h:1237
clang::DiagnosticsEngine::Report
DiagnosticBuilder Report(SourceLocation Loc, unsigned DiagID)
Issue the message to the client.
Definition: Diagnostic.h:1537
clang::ObjCInterfaceDecl::getDefinition
ObjCInterfaceDecl * getDefinition()
Retrieve the definition of this class, or NULL if this class has been forward-declared (with @class) ...
Definition: DeclObjC.h:1527
clang::CXXMethodDecl::getParent
const CXXRecordDecl * getParent() const
Return the parent of this method declaration, which is the class in which this method is defined.
Definition: DeclCXX.h:2098
clang::CXXMethodDecl
Represents a static or instance method of a struct/union/class.
Definition: DeclCXX.h:1983
clang::NamedDecl::getName
StringRef getName() const
Get the name of identifier for this declaration as a StringRef.
Definition: Decl.h:274