clang  14.0.0git
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().isPS4() ||
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  UpdateAlignment(BaseAlign, UnpackedAlignTo, PreferredBaseAlign);
1265 
1266  return CharUnits::Zero();
1267  }
1268 
1269  // The maximum field alignment overrides the base align/(AIX-only) preferred
1270  // base align.
1271  if (!MaxFieldAlignment.isZero()) {
1272  BaseAlign = std::min(BaseAlign, MaxFieldAlignment);
1273  PreferredBaseAlign = std::min(PreferredBaseAlign, MaxFieldAlignment);
1274  UnpackedAlignTo = std::min(UnpackedAlignTo, MaxFieldAlignment);
1275  }
1276 
1277  CharUnits AlignTo =
1278  !DefaultsToAIXPowerAlignment ? BaseAlign : PreferredBaseAlign;
1279  if (!HasExternalLayout) {
1280  // Round up the current record size to the base's alignment boundary.
1281  Offset = getDataSize().alignTo(AlignTo);
1282 
1283  // Try to place the base.
1284  while (!EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset))
1285  Offset += AlignTo;
1286  } else {
1287  bool Allowed = EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset);
1288  (void)Allowed;
1289  assert(Allowed && "Base subobject externally placed at overlapping offset");
1290 
1291  if (InferAlignment && Offset < getDataSize().alignTo(AlignTo)) {
1292  // The externally-supplied base offset is before the base offset we
1293  // computed. Assume that the structure is packed.
1294  Alignment = CharUnits::One();
1295  InferAlignment = false;
1296  }
1297  }
1298 
1299  if (!Base->Class->isEmpty()) {
1300  // Update the data size.
1301  setDataSize(Offset + Layout.getNonVirtualSize());
1302 
1303  setSize(std::max(getSize(), getDataSize()));
1304  } else
1305  setSize(std::max(getSize(), Offset + Layout.getSize()));
1306 
1307  // Remember max struct/class alignment.
1308  UpdateAlignment(BaseAlign, UnpackedAlignTo, PreferredBaseAlign);
1309 
1310  return Offset;
1311 }
1312 
1313 void ItaniumRecordLayoutBuilder::InitializeLayout(const Decl *D) {
1314  if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
1315  IsUnion = RD->isUnion();
1316  IsMsStruct = RD->isMsStruct(Context);
1317  }
1318 
1319  Packed = D->hasAttr<PackedAttr>();
1320 
1321  // Honor the default struct packing maximum alignment flag.
1322  if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct) {
1323  MaxFieldAlignment = CharUnits::fromQuantity(DefaultMaxFieldAlignment);
1324  }
1325 
1326  // mac68k alignment supersedes maximum field alignment and attribute aligned,
1327  // and forces all structures to have 2-byte alignment. The IBM docs on it
1328  // allude to additional (more complicated) semantics, especially with regard
1329  // to bit-fields, but gcc appears not to follow that.
1330  if (D->hasAttr<AlignMac68kAttr>()) {
1331  assert(
1332  !D->hasAttr<AlignNaturalAttr>() &&
1333  "Having both mac68k and natural alignment on a decl is not allowed.");
1334  IsMac68kAlign = true;
1335  MaxFieldAlignment = CharUnits::fromQuantity(2);
1336  Alignment = CharUnits::fromQuantity(2);
1337  PreferredAlignment = CharUnits::fromQuantity(2);
1338  } else {
1339  if (D->hasAttr<AlignNaturalAttr>())
1340  IsNaturalAlign = true;
1341 
1342  if (const MaxFieldAlignmentAttr *MFAA = D->getAttr<MaxFieldAlignmentAttr>())
1343  MaxFieldAlignment = Context.toCharUnitsFromBits(MFAA->getAlignment());
1344 
1345  if (unsigned MaxAlign = D->getMaxAlignment())
1346  UpdateAlignment(Context.toCharUnitsFromBits(MaxAlign));
1347  }
1348 
1349  HandledFirstNonOverlappingEmptyField =
1350  !Context.getTargetInfo().defaultsToAIXPowerAlignment() || IsNaturalAlign;
1351 
1352  // If there is an external AST source, ask it for the various offsets.
1353  if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
1354  if (ExternalASTSource *Source = Context.getExternalSource()) {
1355  UseExternalLayout = Source->layoutRecordType(
1356  RD, External.Size, External.Align, External.FieldOffsets,
1357  External.BaseOffsets, External.VirtualBaseOffsets);
1358 
1359  // Update based on external alignment.
1360  if (UseExternalLayout) {
1361  if (External.Align > 0) {
1362  Alignment = Context.toCharUnitsFromBits(External.Align);
1363  PreferredAlignment = Context.toCharUnitsFromBits(External.Align);
1364  } else {
1365  // The external source didn't have alignment information; infer it.
1366  InferAlignment = true;
1367  }
1368  }
1369  }
1370 }
1371 
1372 void ItaniumRecordLayoutBuilder::Layout(const RecordDecl *D) {
1373  InitializeLayout(D);
1374  LayoutFields(D);
1375 
1376  // Finally, round the size of the total struct up to the alignment of the
1377  // struct itself.
1378  FinishLayout(D);
1379 }
1380 
1381 void ItaniumRecordLayoutBuilder::Layout(const CXXRecordDecl *RD) {
1382  InitializeLayout(RD);
1383 
1384  // Lay out the vtable and the non-virtual bases.
1385  LayoutNonVirtualBases(RD);
1386 
1387  LayoutFields(RD);
1388 
1389  NonVirtualSize = Context.toCharUnitsFromBits(
1390  llvm::alignTo(getSizeInBits(), Context.getTargetInfo().getCharAlign()));
1391  NonVirtualAlignment = Alignment;
1392  PreferredNVAlignment = PreferredAlignment;
1393 
1394  // Lay out the virtual bases and add the primary virtual base offsets.
1395  LayoutVirtualBases(RD, RD);
1396 
1397  // Finally, round the size of the total struct up to the alignment
1398  // of the struct itself.
1399  FinishLayout(RD);
1400 
1401 #ifndef NDEBUG
1402  // Check that we have base offsets for all bases.
1403  for (const CXXBaseSpecifier &Base : RD->bases()) {
1404  if (Base.isVirtual())
1405  continue;
1406 
1407  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1408 
1409  assert(Bases.count(BaseDecl) && "Did not find base offset!");
1410  }
1411 
1412  // And all virtual bases.
1413  for (const CXXBaseSpecifier &Base : RD->vbases()) {
1414  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1415 
1416  assert(VBases.count(BaseDecl) && "Did not find base offset!");
1417  }
1418 #endif
1419 }
1420 
1421 void ItaniumRecordLayoutBuilder::Layout(const ObjCInterfaceDecl *D) {
1422  if (ObjCInterfaceDecl *SD = D->getSuperClass()) {
1423  const ASTRecordLayout &SL = Context.getASTObjCInterfaceLayout(SD);
1424 
1425  UpdateAlignment(SL.getAlignment());
1426 
1427  // We start laying out ivars not at the end of the superclass
1428  // structure, but at the next byte following the last field.
1429  setDataSize(SL.getDataSize());
1430  setSize(getDataSize());
1431  }
1432 
1433  InitializeLayout(D);
1434  // Layout each ivar sequentially.
1435  for (const ObjCIvarDecl *IVD = D->all_declared_ivar_begin(); IVD;
1436  IVD = IVD->getNextIvar())
1437  LayoutField(IVD, false);
1438 
1439  // Finally, round the size of the total struct up to the alignment of the
1440  // struct itself.
1441  FinishLayout(D);
1442 }
1443 
1444 void ItaniumRecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
1445  // Layout each field, for now, just sequentially, respecting alignment. In
1446  // the future, this will need to be tweakable by targets.
1447  bool InsertExtraPadding = D->mayInsertExtraPadding(/*EmitRemark=*/true);
1448  bool HasFlexibleArrayMember = D->hasFlexibleArrayMember();
1449  for (auto I = D->field_begin(), End = D->field_end(); I != End; ++I) {
1450  auto Next(I);
1451  ++Next;
1452  LayoutField(*I,
1453  InsertExtraPadding && (Next != End || !HasFlexibleArrayMember));
1454  }
1455 }
1456 
1457 // Rounds the specified size to have it a multiple of the char size.
1458 static uint64_t
1460  const ASTContext &Context) {
1461  uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
1462  return llvm::alignTo(Size, CharAlignment);
1463 }
1464 
1465 void ItaniumRecordLayoutBuilder::LayoutWideBitField(uint64_t FieldSize,
1466  uint64_t StorageUnitSize,
1467  bool FieldPacked,
1468  const FieldDecl *D) {
1469  assert(Context.getLangOpts().CPlusPlus &&
1470  "Can only have wide bit-fields in C++!");
1471 
1472  // Itanium C++ ABI 2.4:
1473  // If sizeof(T)*8 < n, let T' be the largest integral POD type with
1474  // sizeof(T')*8 <= n.
1475 
1476  QualType IntegralPODTypes[] = {
1477  Context.UnsignedCharTy, Context.UnsignedShortTy, Context.UnsignedIntTy,
1478  Context.UnsignedLongTy, Context.UnsignedLongLongTy
1479  };
1480 
1481  QualType Type;
1482  for (const QualType &QT : IntegralPODTypes) {
1483  uint64_t Size = Context.getTypeSize(QT);
1484 
1485  if (Size > FieldSize)
1486  break;
1487 
1488  Type = QT;
1489  }
1490  assert(!Type.isNull() && "Did not find a type!");
1491 
1492  CharUnits TypeAlign = Context.getTypeAlignInChars(Type);
1493 
1494  // We're not going to use any of the unfilled bits in the last byte.
1495  UnfilledBitsInLastUnit = 0;
1496  LastBitfieldStorageUnitSize = 0;
1497 
1498  uint64_t FieldOffset;
1499  uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;
1500 
1501  if (IsUnion) {
1502  uint64_t RoundedFieldSize = roundUpSizeToCharAlignment(FieldSize,
1503  Context);
1504  setDataSize(std::max(getDataSizeInBits(), RoundedFieldSize));
1505  FieldOffset = 0;
1506  } else {
1507  // The bitfield is allocated starting at the next offset aligned
1508  // appropriately for T', with length n bits.
1509  FieldOffset = llvm::alignTo(getDataSizeInBits(), Context.toBits(TypeAlign));
1510 
1511  uint64_t NewSizeInBits = FieldOffset + FieldSize;
1512 
1513  setDataSize(
1514  llvm::alignTo(NewSizeInBits, Context.getTargetInfo().getCharAlign()));
1515  UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;
1516  }
1517 
1518  // Place this field at the current location.
1519  FieldOffsets.push_back(FieldOffset);
1520 
1521  CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, FieldOffset,
1522  Context.toBits(TypeAlign), FieldPacked, D);
1523 
1524  // Update the size.
1525  setSize(std::max(getSizeInBits(), getDataSizeInBits()));
1526 
1527  // Remember max struct/class alignment.
1528  UpdateAlignment(TypeAlign);
1529 }
1530 
1531 static bool isAIXLayout(const ASTContext &Context) {
1532  return Context.getTargetInfo().getTriple().getOS() == llvm::Triple::AIX;
1533 }
1534 
1535 void ItaniumRecordLayoutBuilder::LayoutBitField(const FieldDecl *D) {
1536  bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
1537  uint64_t FieldSize = D->getBitWidthValue(Context);
1538  TypeInfo FieldInfo = Context.getTypeInfo(D->getType());
1539  uint64_t StorageUnitSize = FieldInfo.Width;
1540  unsigned FieldAlign = FieldInfo.Align;
1541  bool AlignIsRequired = FieldInfo.isAlignRequired();
1542 
1543  // UnfilledBitsInLastUnit is the difference between the end of the
1544  // last allocated bitfield (i.e. the first bit offset available for
1545  // bitfields) and the end of the current data size in bits (i.e. the
1546  // first bit offset available for non-bitfields). The current data
1547  // size in bits is always a multiple of the char size; additionally,
1548  // for ms_struct records it's also a multiple of the
1549  // LastBitfieldStorageUnitSize (if set).
1550 
1551  // The struct-layout algorithm is dictated by the platform ABI,
1552  // which in principle could use almost any rules it likes. In
1553  // practice, UNIXy targets tend to inherit the algorithm described
1554  // in the System V generic ABI. The basic bitfield layout rule in
1555  // System V is to place bitfields at the next available bit offset
1556  // where the entire bitfield would fit in an aligned storage unit of
1557  // the declared type; it's okay if an earlier or later non-bitfield
1558  // is allocated in the same storage unit. However, some targets
1559  // (those that !useBitFieldTypeAlignment(), e.g. ARM APCS) don't
1560  // require this storage unit to be aligned, and therefore always put
1561  // the bitfield at the next available bit offset.
1562 
1563  // ms_struct basically requests a complete replacement of the
1564  // platform ABI's struct-layout algorithm, with the high-level goal
1565  // of duplicating MSVC's layout. For non-bitfields, this follows
1566  // the standard algorithm. The basic bitfield layout rule is to
1567  // allocate an entire unit of the bitfield's declared type
1568  // (e.g. 'unsigned long'), then parcel it up among successive
1569  // bitfields whose declared types have the same size, making a new
1570  // unit as soon as the last can no longer store the whole value.
1571  // Since it completely replaces the platform ABI's algorithm,
1572  // settings like !useBitFieldTypeAlignment() do not apply.
1573 
1574  // A zero-width bitfield forces the use of a new storage unit for
1575  // later bitfields. In general, this occurs by rounding up the
1576  // current size of the struct as if the algorithm were about to
1577  // place a non-bitfield of the field's formal type. Usually this
1578  // does not change the alignment of the struct itself, but it does
1579  // on some targets (those that useZeroLengthBitfieldAlignment(),
1580  // e.g. ARM). In ms_struct layout, zero-width bitfields are
1581  // ignored unless they follow a non-zero-width bitfield.
1582 
1583  // A field alignment restriction (e.g. from #pragma pack) or
1584  // specification (e.g. from __attribute__((aligned))) changes the
1585  // formal alignment of the field. For System V, this alters the
1586  // required alignment of the notional storage unit that must contain
1587  // the bitfield. For ms_struct, this only affects the placement of
1588  // new storage units. In both cases, the effect of #pragma pack is
1589  // ignored on zero-width bitfields.
1590 
1591  // On System V, a packed field (e.g. from #pragma pack or
1592  // __attribute__((packed))) always uses the next available bit
1593  // offset.
1594 
1595  // In an ms_struct struct, the alignment of a fundamental type is
1596  // always equal to its size. This is necessary in order to mimic
1597  // the i386 alignment rules on targets which might not fully align
1598  // all types (e.g. Darwin PPC32, where alignof(long long) == 4).
1599 
1600  // First, some simple bookkeeping to perform for ms_struct structs.
1601  if (IsMsStruct) {
1602  // The field alignment for integer types is always the size.
1603  FieldAlign = StorageUnitSize;
1604 
1605  // If the previous field was not a bitfield, or was a bitfield
1606  // with a different storage unit size, or if this field doesn't fit into
1607  // the current storage unit, we're done with that storage unit.
1608  if (LastBitfieldStorageUnitSize != StorageUnitSize ||
1609  UnfilledBitsInLastUnit < FieldSize) {
1610  // Also, ignore zero-length bitfields after non-bitfields.
1611  if (!LastBitfieldStorageUnitSize && !FieldSize)
1612  FieldAlign = 1;
1613 
1614  UnfilledBitsInLastUnit = 0;
1615  LastBitfieldStorageUnitSize = 0;
1616  }
1617  }
1618 
1619  if (isAIXLayout(Context)) {
1620  if (StorageUnitSize < Context.getTypeSize(Context.UnsignedIntTy)) {
1621  // On AIX, [bool, char, short] bitfields have the same alignment
1622  // as [unsigned].
1623  StorageUnitSize = Context.getTypeSize(Context.UnsignedIntTy);
1624  } else if (StorageUnitSize > Context.getTypeSize(Context.UnsignedIntTy) &&
1625  Context.getTargetInfo().getTriple().isArch32Bit() &&
1626  FieldSize <= 32) {
1627  // Under 32-bit compile mode, the bitcontainer is 32 bits if a single
1628  // long long bitfield has length no greater than 32 bits.
1629  StorageUnitSize = 32;
1630 
1631  if (!AlignIsRequired)
1632  FieldAlign = 32;
1633  }
1634 
1635  if (FieldAlign < StorageUnitSize) {
1636  // The bitfield alignment should always be greater than or equal to
1637  // bitcontainer size.
1638  FieldAlign = StorageUnitSize;
1639  }
1640  }
1641 
1642  // If the field is wider than its declared type, it follows
1643  // different rules in all cases, except on AIX.
1644  // On AIX, wide bitfield follows the same rules as normal bitfield.
1645  if (FieldSize > StorageUnitSize && !isAIXLayout(Context)) {
1646  LayoutWideBitField(FieldSize, StorageUnitSize, FieldPacked, D);
1647  return;
1648  }
1649 
1650  // Compute the next available bit offset.
1651  uint64_t FieldOffset =
1652  IsUnion ? 0 : (getDataSizeInBits() - UnfilledBitsInLastUnit);
1653 
1654  // Handle targets that don't honor bitfield type alignment.
1655  if (!IsMsStruct && !Context.getTargetInfo().useBitFieldTypeAlignment()) {
1656  // Some such targets do honor it on zero-width bitfields.
1657  if (FieldSize == 0 &&
1659  // Some targets don't honor leading zero-width bitfield.
1660  if (!IsUnion && FieldOffset == 0 &&
1662  FieldAlign = 1;
1663  else {
1664  // The alignment to round up to is the max of the field's natural
1665  // alignment and a target-specific fixed value (sometimes zero).
1666  unsigned ZeroLengthBitfieldBoundary =
1668  FieldAlign = std::max(FieldAlign, ZeroLengthBitfieldBoundary);
1669  }
1670  // If that doesn't apply, just ignore the field alignment.
1671  } else {
1672  FieldAlign = 1;
1673  }
1674  }
1675 
1676  // Remember the alignment we would have used if the field were not packed.
1677  unsigned UnpackedFieldAlign = FieldAlign;
1678 
1679  // Ignore the field alignment if the field is packed unless it has zero-size.
1680  if (!IsMsStruct && FieldPacked && FieldSize != 0)
1681  FieldAlign = 1;
1682 
1683  // But, if there's an 'aligned' attribute on the field, honor that.
1684  unsigned ExplicitFieldAlign = D->getMaxAlignment();
1685  if (ExplicitFieldAlign) {
1686  FieldAlign = std::max(FieldAlign, ExplicitFieldAlign);
1687  UnpackedFieldAlign = std::max(UnpackedFieldAlign, ExplicitFieldAlign);
1688  }
1689 
1690  // But, if there's a #pragma pack in play, that takes precedent over
1691  // even the 'aligned' attribute, for non-zero-width bitfields.
1692  unsigned MaxFieldAlignmentInBits = Context.toBits(MaxFieldAlignment);
1693  if (!MaxFieldAlignment.isZero() && FieldSize) {
1694  UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignmentInBits);
1695  if (FieldPacked)
1696  FieldAlign = UnpackedFieldAlign;
1697  else
1698  FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
1699  }
1700 
1701  // But, ms_struct just ignores all of that in unions, even explicit
1702  // alignment attributes.
1703  if (IsMsStruct && IsUnion) {
1704  FieldAlign = UnpackedFieldAlign = 1;
1705  }
1706 
1707  // For purposes of diagnostics, we're going to simultaneously
1708  // compute the field offsets that we would have used if we weren't
1709  // adding any alignment padding or if the field weren't packed.
1710  uint64_t UnpaddedFieldOffset = FieldOffset;
1711  uint64_t UnpackedFieldOffset = FieldOffset;
1712 
1713  // Check if we need to add padding to fit the bitfield within an
1714  // allocation unit with the right size and alignment. The rules are
1715  // somewhat different here for ms_struct structs.
1716  if (IsMsStruct) {
1717  // If it's not a zero-width bitfield, and we can fit the bitfield
1718  // into the active storage unit (and we haven't already decided to
1719  // start a new storage unit), just do so, regardless of any other
1720  // other consideration. Otherwise, round up to the right alignment.
1721  if (FieldSize == 0 || FieldSize > UnfilledBitsInLastUnit) {
1722  FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
1723  UnpackedFieldOffset =
1724  llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
1725  UnfilledBitsInLastUnit = 0;
1726  }
1727 
1728  } else {
1729  // #pragma pack, with any value, suppresses the insertion of padding.
1730  bool AllowPadding = MaxFieldAlignment.isZero();
1731 
1732  // Compute the real offset.
1733  if (FieldSize == 0 ||
1734  (AllowPadding &&
1735  (FieldOffset & (FieldAlign - 1)) + FieldSize > StorageUnitSize)) {
1736  FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
1737  } else if (ExplicitFieldAlign &&
1738  (MaxFieldAlignmentInBits == 0 ||
1739  ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
1741  // TODO: figure it out what needs to be done on targets that don't honor
1742  // bit-field type alignment like ARM APCS ABI.
1743  FieldOffset = llvm::alignTo(FieldOffset, ExplicitFieldAlign);
1744  }
1745 
1746  // Repeat the computation for diagnostic purposes.
1747  if (FieldSize == 0 ||
1748  (AllowPadding &&
1749  (UnpackedFieldOffset & (UnpackedFieldAlign - 1)) + FieldSize >
1750  StorageUnitSize))
1751  UnpackedFieldOffset =
1752  llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
1753  else if (ExplicitFieldAlign &&
1754  (MaxFieldAlignmentInBits == 0 ||
1755  ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
1757  UnpackedFieldOffset =
1758  llvm::alignTo(UnpackedFieldOffset, ExplicitFieldAlign);
1759  }
1760 
1761  // If we're using external layout, give the external layout a chance
1762  // to override this information.
1763  if (UseExternalLayout)
1764  FieldOffset = updateExternalFieldOffset(D, FieldOffset);
1765 
1766  // Okay, place the bitfield at the calculated offset.
1767  FieldOffsets.push_back(FieldOffset);
1768 
1769  // Bookkeeping:
1770 
1771  // Anonymous members don't affect the overall record alignment,
1772  // except on targets where they do.
1773  if (!IsMsStruct &&
1775  !D->getIdentifier())
1776  FieldAlign = UnpackedFieldAlign = 1;
1777 
1778  // On AIX, zero-width bitfields pad out to the natural alignment boundary,
1779  // but do not increase the alignment greater than the MaxFieldAlignment, or 1
1780  // if packed.
1781  if (isAIXLayout(Context) && !FieldSize) {
1782  if (FieldPacked)
1783  FieldAlign = 1;
1784  if (!MaxFieldAlignment.isZero()) {
1785  UnpackedFieldAlign =
1786  std::min(UnpackedFieldAlign, MaxFieldAlignmentInBits);
1787  FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
1788  }
1789  }
1790 
1791  // Diagnose differences in layout due to padding or packing.
1792  if (!UseExternalLayout)
1793  CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, UnpackedFieldOffset,
1794  UnpackedFieldAlign, FieldPacked, D);
1795 
1796  // Update DataSize to include the last byte containing (part of) the bitfield.
1797 
1798  // For unions, this is just a max operation, as usual.
1799  if (IsUnion) {
1800  // For ms_struct, allocate the entire storage unit --- unless this
1801  // is a zero-width bitfield, in which case just use a size of 1.
1802  uint64_t RoundedFieldSize;
1803  if (IsMsStruct) {
1804  RoundedFieldSize = (FieldSize ? StorageUnitSize
1805  : Context.getTargetInfo().getCharWidth());
1806 
1807  // Otherwise, allocate just the number of bytes required to store
1808  // the bitfield.
1809  } else {
1810  RoundedFieldSize = roundUpSizeToCharAlignment(FieldSize, Context);
1811  }
1812  setDataSize(std::max(getDataSizeInBits(), RoundedFieldSize));
1813 
1814  // For non-zero-width bitfields in ms_struct structs, allocate a new
1815  // storage unit if necessary.
1816  } else if (IsMsStruct && FieldSize) {
1817  // We should have cleared UnfilledBitsInLastUnit in every case
1818  // where we changed storage units.
1819  if (!UnfilledBitsInLastUnit) {
1820  setDataSize(FieldOffset + StorageUnitSize);
1821  UnfilledBitsInLastUnit = StorageUnitSize;
1822  }
1823  UnfilledBitsInLastUnit -= FieldSize;
1824  LastBitfieldStorageUnitSize = StorageUnitSize;
1825 
1826  // Otherwise, bump the data size up to include the bitfield,
1827  // including padding up to char alignment, and then remember how
1828  // bits we didn't use.
1829  } else {
1830  uint64_t NewSizeInBits = FieldOffset + FieldSize;
1831  uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
1832  setDataSize(llvm::alignTo(NewSizeInBits, CharAlignment));
1833  UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;
1834 
1835  // The only time we can get here for an ms_struct is if this is a
1836  // zero-width bitfield, which doesn't count as anything for the
1837  // purposes of unfilled bits.
1838  LastBitfieldStorageUnitSize = 0;
1839  }
1840 
1841  // Update the size.
1842  setSize(std::max(getSizeInBits(), getDataSizeInBits()));
1843 
1844  // Remember max struct/class alignment.
1845  UnadjustedAlignment =
1846  std::max(UnadjustedAlignment, Context.toCharUnitsFromBits(FieldAlign));
1847  UpdateAlignment(Context.toCharUnitsFromBits(FieldAlign),
1848  Context.toCharUnitsFromBits(UnpackedFieldAlign));
1849 }
1850 
1851 void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D,
1852  bool InsertExtraPadding) {
1853  auto *FieldClass = D->getType()->getAsCXXRecordDecl();
1854  bool PotentiallyOverlapping = D->hasAttr<NoUniqueAddressAttr>() && FieldClass;
1855  bool IsOverlappingEmptyField =
1856  PotentiallyOverlapping && FieldClass->isEmpty();
1857 
1858  CharUnits FieldOffset =
1859  (IsUnion || IsOverlappingEmptyField) ? CharUnits::Zero() : getDataSize();
1860 
1861  const bool DefaultsToAIXPowerAlignment =
1863  bool FoundFirstNonOverlappingEmptyFieldForAIX = false;
1864  if (DefaultsToAIXPowerAlignment && !HandledFirstNonOverlappingEmptyField) {
1865  assert(FieldOffset == CharUnits::Zero() &&
1866  "The first non-overlapping empty field should have been handled.");
1867 
1868  if (!IsOverlappingEmptyField) {
1869  FoundFirstNonOverlappingEmptyFieldForAIX = true;
1870 
1871  // We're going to handle the "first member" based on
1872  // `FoundFirstNonOverlappingEmptyFieldForAIX` during the current
1873  // invocation of this function; record it as handled for future
1874  // invocations (except for unions, because the current field does not
1875  // represent all "firsts").
1876  HandledFirstNonOverlappingEmptyField = !IsUnion;
1877  }
1878  }
1879 
1880  if (D->isBitField()) {
1881  LayoutBitField(D);
1882  return;
1883  }
1884 
1885  uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;
1886  // Reset the unfilled bits.
1887  UnfilledBitsInLastUnit = 0;
1888  LastBitfieldStorageUnitSize = 0;
1889 
1890  bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
1891 
1893  CharUnits FieldSize;
1894  CharUnits FieldAlign;
1895  // The amount of this class's dsize occupied by the field.
1896  // This is equal to FieldSize unless we're permitted to pack
1897  // into the field's tail padding.
1898  CharUnits EffectiveFieldSize;
1899 
1900  auto setDeclInfo = [&](bool IsIncompleteArrayType) {
1901  auto TI = Context.getTypeInfoInChars(D->getType());
1902  FieldAlign = TI.Align;
1903  // Flexible array members don't have any size, but they have to be
1904  // aligned appropriately for their element type.
1905  EffectiveFieldSize = FieldSize =
1906  IsIncompleteArrayType ? CharUnits::Zero() : TI.Width;
1907  AlignRequirement = TI.AlignRequirement;
1908  };
1909 
1910  if (D->getType()->isIncompleteArrayType()) {
1911  setDeclInfo(true /* IsIncompleteArrayType */);
1912  } else if (const ReferenceType *RT = D->getType()->getAs<ReferenceType>()) {
1913  unsigned AS = Context.getTargetAddressSpace(RT->getPointeeType());
1914  EffectiveFieldSize = FieldSize = Context.toCharUnitsFromBits(
1915  Context.getTargetInfo().getPointerWidth(AS));
1916  FieldAlign = Context.toCharUnitsFromBits(
1917  Context.getTargetInfo().getPointerAlign(AS));
1918  } else {
1919  setDeclInfo(false /* IsIncompleteArrayType */);
1920 
1921  // A potentially-overlapping field occupies its dsize or nvsize, whichever
1922  // is larger.
1923  if (PotentiallyOverlapping) {
1924  const ASTRecordLayout &Layout = Context.getASTRecordLayout(FieldClass);
1925  EffectiveFieldSize =
1926  std::max(Layout.getNonVirtualSize(), Layout.getDataSize());
1927  }
1928 
1929  if (IsMsStruct) {
1930  // If MS bitfield layout is required, figure out what type is being
1931  // laid out and align the field to the width of that type.
1932 
1933  // Resolve all typedefs down to their base type and round up the field
1934  // alignment if necessary.
1935  QualType T = Context.getBaseElementType(D->getType());
1936  if (const BuiltinType *BTy = T->getAs<BuiltinType>()) {
1937  CharUnits TypeSize = Context.getTypeSizeInChars(BTy);
1938 
1939  if (!llvm::isPowerOf2_64(TypeSize.getQuantity())) {
1940  assert(
1941  !Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() &&
1942  "Non PowerOf2 size in MSVC mode");
1943  // Base types with sizes that aren't a power of two don't work
1944  // with the layout rules for MS structs. This isn't an issue in
1945  // MSVC itself since there are no such base data types there.
1946  // On e.g. x86_32 mingw and linux, long double is 12 bytes though.
1947  // Any structs involving that data type obviously can't be ABI
1948  // compatible with MSVC regardless of how it is laid out.
1949 
1950  // Since ms_struct can be mass enabled (via a pragma or via the
1951  // -mms-bitfields command line parameter), this can trigger for
1952  // structs that don't actually need MSVC compatibility, so we
1953  // need to be able to sidestep the ms_struct layout for these types.
1954 
1955  // Since the combination of -mms-bitfields together with structs
1956  // like max_align_t (which contains a long double) for mingw is
1957  // quite common (and GCC handles it silently), just handle it
1958  // silently there. For other targets that have ms_struct enabled
1959  // (most probably via a pragma or attribute), trigger a diagnostic
1960  // that defaults to an error.
1961  if (!Context.getTargetInfo().getTriple().isWindowsGNUEnvironment())
1962  Diag(D->getLocation(), diag::warn_npot_ms_struct);
1963  }
1964  if (TypeSize > FieldAlign &&
1965  llvm::isPowerOf2_64(TypeSize.getQuantity()))
1966  FieldAlign = TypeSize;
1967  }
1968  }
1969  }
1970 
1971  // When used as part of a typedef, or together with a 'packed' attribute, the
1972  // 'aligned' attribute can be used to decrease alignment. In that case, it
1973  // overrides any computed alignment we have, and there is no need to upgrade
1974  // the alignment.
1975  auto alignedAttrCanDecreaseAIXAlignment = [AlignRequirement, FieldPacked] {
1976  // Enum alignment sources can be safely ignored here, because this only
1977  // helps decide whether we need the AIX alignment upgrade, which only
1978  // applies to floating-point types.
1979  return AlignRequirement == AlignRequirementKind::RequiredByTypedef ||
1980  (AlignRequirement == AlignRequirementKind::RequiredByRecord &&
1981  FieldPacked);
1982  };
1983 
1984  // The AIX `power` alignment rules apply the natural alignment of the
1985  // "first member" if it is of a floating-point data type (or is an aggregate
1986  // whose recursively "first" member or element is such a type). The alignment
1987  // associated with these types for subsequent members use an alignment value
1988  // where the floating-point data type is considered to have 4-byte alignment.
1989  //
1990  // For the purposes of the foregoing: vtable pointers, non-empty base classes,
1991  // and zero-width bit-fields count as prior members; members of empty class
1992  // types marked `no_unique_address` are not considered to be prior members.
1993  CharUnits PreferredAlign = FieldAlign;
1994  if (DefaultsToAIXPowerAlignment && !alignedAttrCanDecreaseAIXAlignment() &&
1995  (FoundFirstNonOverlappingEmptyFieldForAIX || IsNaturalAlign)) {
1996  auto performBuiltinTypeAlignmentUpgrade = [&](const BuiltinType *BTy) {
1997  if (BTy->getKind() == BuiltinType::Double ||
1998  BTy->getKind() == BuiltinType::LongDouble) {
1999  assert(PreferredAlign == CharUnits::fromQuantity(4) &&
2000  "No need to upgrade the alignment value.");
2001  PreferredAlign = CharUnits::fromQuantity(8);
2002  }
2003  };
2004 
2005  const Type *BaseTy = D->getType()->getBaseElementTypeUnsafe();
2006  if (const ComplexType *CTy = BaseTy->getAs<ComplexType>()) {
2007  performBuiltinTypeAlignmentUpgrade(
2008  CTy->getElementType()->castAs<BuiltinType>());
2009  } else if (const BuiltinType *BTy = BaseTy->getAs<BuiltinType>()) {
2010  performBuiltinTypeAlignmentUpgrade(BTy);
2011  } else if (const RecordType *RT = BaseTy->getAs<RecordType>()) {
2012  const RecordDecl *RD = RT->getDecl();
2013  assert(RD && "Expected non-null RecordDecl.");
2014  const ASTRecordLayout &FieldRecord = Context.getASTRecordLayout(RD);
2015  PreferredAlign = FieldRecord.getPreferredAlignment();
2016  }
2017  }
2018 
2019  // The align if the field is not packed. This is to check if the attribute
2020  // was unnecessary (-Wpacked).
2021  CharUnits UnpackedFieldAlign =
2022  !DefaultsToAIXPowerAlignment ? FieldAlign : PreferredAlign;
2023  CharUnits UnpackedFieldOffset = FieldOffset;
2024 
2025  if (FieldPacked) {
2026  FieldAlign = CharUnits::One();
2027  PreferredAlign = CharUnits::One();
2028  }
2029  CharUnits MaxAlignmentInChars =
2030  Context.toCharUnitsFromBits(D->getMaxAlignment());
2031  FieldAlign = std::max(FieldAlign, MaxAlignmentInChars);
2032  PreferredAlign = std::max(PreferredAlign, MaxAlignmentInChars);
2033  UnpackedFieldAlign = std::max(UnpackedFieldAlign, MaxAlignmentInChars);
2034 
2035  // The maximum field alignment overrides the aligned attribute.
2036  if (!MaxFieldAlignment.isZero()) {
2037  FieldAlign = std::min(FieldAlign, MaxFieldAlignment);
2038  PreferredAlign = std::min(PreferredAlign, MaxFieldAlignment);
2039  UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignment);
2040  }
2041 
2042  CharUnits AlignTo =
2043  !DefaultsToAIXPowerAlignment ? FieldAlign : PreferredAlign;
2044  // Round up the current record size to the field's alignment boundary.
2045  FieldOffset = FieldOffset.alignTo(AlignTo);
2046  UnpackedFieldOffset = UnpackedFieldOffset.alignTo(UnpackedFieldAlign);
2047 
2048  if (UseExternalLayout) {
2049  FieldOffset = Context.toCharUnitsFromBits(
2050  updateExternalFieldOffset(D, Context.toBits(FieldOffset)));
2051 
2052  if (!IsUnion && EmptySubobjects) {
2053  // Record the fact that we're placing a field at this offset.
2054  bool Allowed = EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset);
2055  (void)Allowed;
2056  assert(Allowed && "Externally-placed field cannot be placed here");
2057  }
2058  } else {
2059  if (!IsUnion && EmptySubobjects) {
2060  // Check if we can place the field at this offset.
2061  while (!EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset)) {
2062  // We couldn't place the field at the offset. Try again at a new offset.
2063  // We try offset 0 (for an empty field) and then dsize(C) onwards.
2064  if (FieldOffset == CharUnits::Zero() &&
2065  getDataSize() != CharUnits::Zero())
2066  FieldOffset = getDataSize().alignTo(AlignTo);
2067  else
2068  FieldOffset += AlignTo;
2069  }
2070  }
2071  }
2072 
2073  // Place this field at the current location.
2074  FieldOffsets.push_back(Context.toBits(FieldOffset));
2075 
2076  if (!UseExternalLayout)
2077  CheckFieldPadding(Context.toBits(FieldOffset), UnpaddedFieldOffset,
2078  Context.toBits(UnpackedFieldOffset),
2079  Context.toBits(UnpackedFieldAlign), FieldPacked, D);
2080 
2081  if (InsertExtraPadding) {
2082  CharUnits ASanAlignment = CharUnits::fromQuantity(8);
2083  CharUnits ExtraSizeForAsan = ASanAlignment;
2084  if (FieldSize % ASanAlignment)
2085  ExtraSizeForAsan +=
2086  ASanAlignment - CharUnits::fromQuantity(FieldSize % ASanAlignment);
2087  EffectiveFieldSize = FieldSize = FieldSize + ExtraSizeForAsan;
2088  }
2089 
2090  // Reserve space for this field.
2091  if (!IsOverlappingEmptyField) {
2092  uint64_t EffectiveFieldSizeInBits = Context.toBits(EffectiveFieldSize);
2093  if (IsUnion)
2094  setDataSize(std::max(getDataSizeInBits(), EffectiveFieldSizeInBits));
2095  else
2096  setDataSize(FieldOffset + EffectiveFieldSize);
2097 
2098  PaddedFieldSize = std::max(PaddedFieldSize, FieldOffset + FieldSize);
2099  setSize(std::max(getSizeInBits(), getDataSizeInBits()));
2100  } else {
2101  setSize(std::max(getSizeInBits(),
2102  (uint64_t)Context.toBits(FieldOffset + FieldSize)));
2103  }
2104 
2105  // Remember max struct/class ABI-specified alignment.
2106  UnadjustedAlignment = std::max(UnadjustedAlignment, FieldAlign);
2107  UpdateAlignment(FieldAlign, UnpackedFieldAlign, PreferredAlign);
2108 }
2109 
2110 void ItaniumRecordLayoutBuilder::FinishLayout(const NamedDecl *D) {
2111  // In C++, records cannot be of size 0.
2112  if (Context.getLangOpts().CPlusPlus && getSizeInBits() == 0) {
2113  if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
2114  // Compatibility with gcc requires a class (pod or non-pod)
2115  // which is not empty but of size 0; such as having fields of
2116  // array of zero-length, remains of Size 0
2117  if (RD->isEmpty())
2118  setSize(CharUnits::One());
2119  }
2120  else
2121  setSize(CharUnits::One());
2122  }
2123 
2124  // If we have any remaining field tail padding, include that in the overall
2125  // size.
2126  setSize(std::max(getSizeInBits(), (uint64_t)Context.toBits(PaddedFieldSize)));
2127 
2128  // Finally, round the size of the record up to the alignment of the
2129  // record itself.
2130  uint64_t UnpaddedSize = getSizeInBits() - UnfilledBitsInLastUnit;
2131  uint64_t UnpackedSizeInBits =
2132  llvm::alignTo(getSizeInBits(), Context.toBits(UnpackedAlignment));
2133 
2134  uint64_t RoundedSize = llvm::alignTo(
2135  getSizeInBits(),
2136  Context.toBits(!Context.getTargetInfo().defaultsToAIXPowerAlignment()
2137  ? Alignment
2138  : PreferredAlignment));
2139 
2140  if (UseExternalLayout) {
2141  // If we're inferring alignment, and the external size is smaller than
2142  // our size after we've rounded up to alignment, conservatively set the
2143  // alignment to 1.
2144  if (InferAlignment && External.Size < RoundedSize) {
2145  Alignment = CharUnits::One();
2146  PreferredAlignment = CharUnits::One();
2147  InferAlignment = false;
2148  }
2149  setSize(External.Size);
2150  return;
2151  }
2152 
2153  // Set the size to the final size.
2154  setSize(RoundedSize);
2155 
2156  unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
2157  if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
2158  // Warn if padding was introduced to the struct/class/union.
2159  if (getSizeInBits() > UnpaddedSize) {
2160  unsigned PadSize = getSizeInBits() - UnpaddedSize;
2161  bool InBits = true;
2162  if (PadSize % CharBitNum == 0) {
2163  PadSize = PadSize / CharBitNum;
2164  InBits = false;
2165  }
2166  Diag(RD->getLocation(), diag::warn_padded_struct_size)
2167  << Context.getTypeDeclType(RD)
2168  << PadSize
2169  << (InBits ? 1 : 0); // (byte|bit)
2170  }
2171 
2172  // Warn if we packed it unnecessarily, when the unpacked alignment is not
2173  // greater than the one after packing, the size in bits doesn't change and
2174  // the offset of each field is identical.
2175  if (Packed && UnpackedAlignment <= Alignment &&
2176  UnpackedSizeInBits == getSizeInBits() && !HasPackedField)
2177  Diag(D->getLocation(), diag::warn_unnecessary_packed)
2178  << Context.getTypeDeclType(RD);
2179  }
2180 }
2181 
2182 void ItaniumRecordLayoutBuilder::UpdateAlignment(
2183  CharUnits NewAlignment, CharUnits UnpackedNewAlignment,
2184  CharUnits PreferredNewAlignment) {
2185  // The alignment is not modified when using 'mac68k' alignment or when
2186  // we have an externally-supplied layout that also provides overall alignment.
2187  if (IsMac68kAlign || (UseExternalLayout && !InferAlignment))
2188  return;
2189 
2190  if (NewAlignment > Alignment) {
2191  assert(llvm::isPowerOf2_64(NewAlignment.getQuantity()) &&
2192  "Alignment not a power of 2");
2193  Alignment = NewAlignment;
2194  }
2195 
2196  if (UnpackedNewAlignment > UnpackedAlignment) {
2197  assert(llvm::isPowerOf2_64(UnpackedNewAlignment.getQuantity()) &&
2198  "Alignment not a power of 2");
2199  UnpackedAlignment = UnpackedNewAlignment;
2200  }
2201 
2202  if (PreferredNewAlignment > PreferredAlignment) {
2203  assert(llvm::isPowerOf2_64(PreferredNewAlignment.getQuantity()) &&
2204  "Alignment not a power of 2");
2205  PreferredAlignment = PreferredNewAlignment;
2206  }
2207 }
2208 
2209 uint64_t
2210 ItaniumRecordLayoutBuilder::updateExternalFieldOffset(const FieldDecl *Field,
2211  uint64_t ComputedOffset) {
2212  uint64_t ExternalFieldOffset = External.getExternalFieldOffset(Field);
2213 
2214  if (InferAlignment && ExternalFieldOffset < ComputedOffset) {
2215  // The externally-supplied field offset is before the field offset we
2216  // computed. Assume that the structure is packed.
2217  Alignment = CharUnits::One();
2218  PreferredAlignment = CharUnits::One();
2219  InferAlignment = false;
2220  }
2221 
2222  // Use the externally-supplied field offset.
2223  return ExternalFieldOffset;
2224 }
2225 
2226 /// Get diagnostic %select index for tag kind for
2227 /// field padding diagnostic message.
2228 /// WARNING: Indexes apply to particular diagnostics only!
2229 ///
2230 /// \returns diagnostic %select index.
2232  switch (Tag) {
2233  case TTK_Struct: return 0;
2234  case TTK_Interface: return 1;
2235  case TTK_Class: return 2;
2236  default: llvm_unreachable("Invalid tag kind for field padding diagnostic!");
2237  }
2238 }
2239 
2240 void ItaniumRecordLayoutBuilder::CheckFieldPadding(
2241  uint64_t Offset, uint64_t UnpaddedOffset, uint64_t UnpackedOffset,
2242  unsigned UnpackedAlign, bool isPacked, const FieldDecl *D) {
2243  // We let objc ivars without warning, objc interfaces generally are not used
2244  // for padding tricks.
2245  if (isa<ObjCIvarDecl>(D))
2246  return;
2247 
2248  // Don't warn about structs created without a SourceLocation. This can
2249  // be done by clients of the AST, such as codegen.
2250  if (D->getLocation().isInvalid())
2251  return;
2252 
2253  unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
2254 
2255  // Warn if padding was introduced to the struct/class.
2256  if (!IsUnion && Offset > UnpaddedOffset) {
2257  unsigned PadSize = Offset - UnpaddedOffset;
2258  bool InBits = true;
2259  if (PadSize % CharBitNum == 0) {
2260  PadSize = PadSize / CharBitNum;
2261  InBits = false;
2262  }
2263  if (D->getIdentifier())
2264  Diag(D->getLocation(), diag::warn_padded_struct_field)
2266  << Context.getTypeDeclType(D->getParent())
2267  << PadSize
2268  << (InBits ? 1 : 0) // (byte|bit)
2269  << D->getIdentifier();
2270  else
2271  Diag(D->getLocation(), diag::warn_padded_struct_anon_field)
2273  << Context.getTypeDeclType(D->getParent())
2274  << PadSize
2275  << (InBits ? 1 : 0); // (byte|bit)
2276  }
2277  if (isPacked && Offset != UnpackedOffset) {
2278  HasPackedField = true;
2279  }
2280 }
2281 
2283  const CXXRecordDecl *RD) {
2284  // If a class isn't polymorphic it doesn't have a key function.
2285  if (!RD->isPolymorphic())
2286  return nullptr;
2287 
2288  // A class that is not externally visible doesn't have a key function. (Or
2289  // at least, there's no point to assigning a key function to such a class;
2290  // this doesn't affect the ABI.)
2291  if (!RD->isExternallyVisible())
2292  return nullptr;
2293 
2294  // Template instantiations don't have key functions per Itanium C++ ABI 5.2.6.
2295  // Same behavior as GCC.
2297  if (TSK == TSK_ImplicitInstantiation ||
2300  return nullptr;
2301 
2302  bool allowInlineFunctions =
2304 
2305  for (const CXXMethodDecl *MD : RD->methods()) {
2306  if (!MD->isVirtual())
2307  continue;
2308 
2309  if (MD->isPure())
2310  continue;
2311 
2312  // Ignore implicit member functions, they are always marked as inline, but
2313  // they don't have a body until they're defined.
2314  if (MD->isImplicit())
2315  continue;
2316 
2317  if (MD->isInlineSpecified() || MD->isConstexpr())
2318  continue;
2319 
2320  if (MD->hasInlineBody())
2321  continue;
2322 
2323  // Ignore inline deleted or defaulted functions.
2324  if (!MD->isUserProvided())
2325  continue;
2326 
2327  // In certain ABIs, ignore functions with out-of-line inline definitions.
2328  if (!allowInlineFunctions) {
2329  const FunctionDecl *Def;
2330  if (MD->hasBody(Def) && Def->isInlineSpecified())
2331  continue;
2332  }
2333 
2334  if (Context.getLangOpts().CUDA) {
2335  // While compiler may see key method in this TU, during CUDA
2336  // compilation we should ignore methods that are not accessible
2337  // on this side of compilation.
2338  if (Context.getLangOpts().CUDAIsDevice) {
2339  // In device mode ignore methods without __device__ attribute.
2340  if (!MD->hasAttr<CUDADeviceAttr>())
2341  continue;
2342  } else {
2343  // In host mode ignore __device__-only methods.
2344  if (!MD->hasAttr<CUDAHostAttr>() && MD->hasAttr<CUDADeviceAttr>())
2345  continue;
2346  }
2347  }
2348 
2349  // If the key function is dllimport but the class isn't, then the class has
2350  // no key function. The DLL that exports the key function won't export the
2351  // vtable in this case.
2352  if (MD->hasAttr<DLLImportAttr>() && !RD->hasAttr<DLLImportAttr>() &&
2353  !Context.getTargetInfo().hasPS4DLLImportExport())
2354  return nullptr;
2355 
2356  // We found it.
2357  return MD;
2358  }
2359 
2360  return nullptr;
2361 }
2362 
2364  unsigned DiagID) {
2365  return Context.getDiagnostics().Report(Loc, DiagID);
2366 }
2367 
2368 /// Does the target C++ ABI require us to skip over the tail-padding
2369 /// of the given class (considering it as a base class) when allocating
2370 /// objects?
2371 static bool mustSkipTailPadding(TargetCXXABI ABI, const CXXRecordDecl *RD) {
2372  switch (ABI.getTailPaddingUseRules()) {
2374  return false;
2375 
2377  // FIXME: To the extent that this is meant to cover the Itanium ABI
2378  // rules, we should implement the restrictions about over-sized
2379  // bitfields:
2380  //
2381  // http://itanium-cxx-abi.github.io/cxx-abi/abi.html#POD :
2382  // In general, a type is considered a POD for the purposes of
2383  // layout if it is a POD type (in the sense of ISO C++
2384  // [basic.types]). However, a POD-struct or POD-union (in the
2385  // sense of ISO C++ [class]) with a bitfield member whose
2386  // declared width is wider than the declared type of the
2387  // bitfield is not a POD for the purpose of layout. Similarly,
2388  // an array type is not a POD for the purpose of layout if the
2389  // element type of the array is not a POD for the purpose of
2390  // layout.
2391  //
2392  // Where references to the ISO C++ are made in this paragraph,
2393  // the Technical Corrigendum 1 version of the standard is
2394  // intended.
2395  return RD->isPOD();
2396 
2398  // This is equivalent to RD->getTypeForDecl().isCXX11PODType(),
2399  // but with a lot of abstraction penalty stripped off. This does
2400  // assume that these properties are set correctly even in C++98
2401  // mode; fortunately, that is true because we want to assign
2402  // consistently semantics to the type-traits intrinsics (or at
2403  // least as many of them as possible).
2404  return RD->isTrivial() && RD->isCXX11StandardLayout();
2405  }
2406 
2407  llvm_unreachable("bad tail-padding use kind");
2408 }
2409 
2410 static bool isMsLayout(const ASTContext &Context) {
2411  return Context.getTargetInfo().getCXXABI().isMicrosoft();
2412 }
2413 
2414 // This section contains an implementation of struct layout that is, up to the
2415 // included tests, compatible with cl.exe (2013). The layout produced is
2416 // significantly different than those produced by the Itanium ABI. Here we note
2417 // the most important differences.
2418 //
2419 // * The alignment of bitfields in unions is ignored when computing the
2420 // alignment of the union.
2421 // * The existence of zero-width bitfield that occurs after anything other than
2422 // a non-zero length bitfield is ignored.
2423 // * There is no explicit primary base for the purposes of layout. All bases
2424 // with vfptrs are laid out first, followed by all bases without vfptrs.
2425 // * The Itanium equivalent vtable pointers are split into a vfptr (virtual
2426 // function pointer) and a vbptr (virtual base pointer). They can each be
2427 // shared with a, non-virtual bases. These bases need not be the same. vfptrs
2428 // always occur at offset 0. vbptrs can occur at an arbitrary offset and are
2429 // placed after the lexicographically last non-virtual base. This placement
2430 // is always before fields but can be in the middle of the non-virtual bases
2431 // due to the two-pass layout scheme for non-virtual-bases.
2432 // * Virtual bases sometimes require a 'vtordisp' field that is laid out before
2433 // the virtual base and is used in conjunction with virtual overrides during
2434 // construction and destruction. This is always a 4 byte value and is used as
2435 // an alternative to constructor vtables.
2436 // * vtordisps are allocated in a block of memory with size and alignment equal
2437 // to the alignment of the completed structure (before applying __declspec(
2438 // align())). The vtordisp always occur at the end of the allocation block,
2439 // immediately prior to the virtual base.
2440 // * vfptrs are injected after all bases and fields have been laid out. In
2441 // order to guarantee proper alignment of all fields, the vfptr injection
2442 // pushes all bases and fields back by the alignment imposed by those bases
2443 // and fields. This can potentially add a significant amount of padding.
2444 // vfptrs are always injected at offset 0.
2445 // * vbptrs are injected after all bases and fields have been laid out. In
2446 // order to guarantee proper alignment of all fields, the vfptr injection
2447 // pushes all bases and fields back by the alignment imposed by those bases
2448 // and fields. This can potentially add a significant amount of padding.
2449 // vbptrs are injected immediately after the last non-virtual base as
2450 // lexicographically ordered in the code. If this site isn't pointer aligned
2451 // the vbptr is placed at the next properly aligned location. Enough padding
2452 // is added to guarantee a fit.
2453 // * The last zero sized non-virtual base can be placed at the end of the
2454 // struct (potentially aliasing another object), or may alias with the first
2455 // field, even if they are of the same type.
2456 // * The last zero size virtual base may be placed at the end of the struct
2457 // potentially aliasing another object.
2458 // * The ABI attempts to avoid aliasing of zero sized bases by adding padding
2459 // between bases or vbases with specific properties. The criteria for
2460 // additional padding between two bases is that the first base is zero sized
2461 // or ends with a zero sized subobject and the second base is zero sized or
2462 // trails with a zero sized base or field (sharing of vfptrs can reorder the
2463 // layout of the so the leading base is not always the first one declared).
2464 // This rule does take into account fields that are not records, so padding
2465 // will occur even if the last field is, e.g. an int. The padding added for
2466 // bases is 1 byte. The padding added between vbases depends on the alignment
2467 // of the object but is at least 4 bytes (in both 32 and 64 bit modes).
2468 // * There is no concept of non-virtual alignment, non-virtual alignment and
2469 // alignment are always identical.
2470 // * There is a distinction between alignment and required alignment.
2471 // __declspec(align) changes the required alignment of a struct. This
2472 // alignment is _always_ obeyed, even in the presence of #pragma pack. A
2473 // record inherits required alignment from all of its fields and bases.
2474 // * __declspec(align) on bitfields has the effect of changing the bitfield's
2475 // alignment instead of its required alignment. This is the only known way
2476 // to make the alignment of a struct bigger than 8. Interestingly enough
2477 // this alignment is also immune to the effects of #pragma pack and can be
2478 // used to create structures with large alignment under #pragma pack.
2479 // However, because it does not impact required alignment, such a structure,
2480 // when used as a field or base, will not be aligned if #pragma pack is
2481 // still active at the time of use.
2482 //
2483 // Known incompatibilities:
2484 // * all: #pragma pack between fields in a record
2485 // * 2010 and back: If the last field in a record is a bitfield, every object
2486 // laid out after the record will have extra padding inserted before it. The
2487 // extra padding will have size equal to the size of the storage class of the
2488 // bitfield. 0 sized bitfields don't exhibit this behavior and the extra
2489 // padding can be avoided by adding a 0 sized bitfield after the non-zero-
2490 // sized bitfield.
2491 // * 2012 and back: In 64-bit mode, if the alignment of a record is 16 or
2492 // greater due to __declspec(align()) then a second layout phase occurs after
2493 // The locations of the vf and vb pointers are known. This layout phase
2494 // suffers from the "last field is a bitfield" bug in 2010 and results in
2495 // _every_ field getting padding put in front of it, potentially including the
2496 // vfptr, leaving the vfprt at a non-zero location which results in a fault if
2497 // anything tries to read the vftbl. The second layout phase also treats
2498 // bitfields as separate entities and gives them each storage rather than
2499 // packing them. Additionally, because this phase appears to perform a
2500 // (an unstable) sort on the members before laying them out and because merged
2501 // bitfields have the same address, the bitfields end up in whatever order
2502 // the sort left them in, a behavior we could never hope to replicate.
2503 
2504 namespace {
2505 struct MicrosoftRecordLayoutBuilder {
2506  struct ElementInfo {
2507  CharUnits Size;
2508  CharUnits Alignment;
2509  };
2510  typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
2511  MicrosoftRecordLayoutBuilder(const ASTContext &Context) : Context(Context) {}
2512 private:
2513  MicrosoftRecordLayoutBuilder(const MicrosoftRecordLayoutBuilder &) = delete;
2514  void operator=(const MicrosoftRecordLayoutBuilder &) = delete;
2515 public:
2516  void layout(const RecordDecl *RD);
2517  void cxxLayout(const CXXRecordDecl *RD);
2518  /// Initializes size and alignment and honors some flags.
2519  void initializeLayout(const RecordDecl *RD);
2520  /// Initialized C++ layout, compute alignment and virtual alignment and
2521  /// existence of vfptrs and vbptrs. Alignment is needed before the vfptr is
2522  /// laid out.
2523  void initializeCXXLayout(const CXXRecordDecl *RD);
2524  void layoutNonVirtualBases(const CXXRecordDecl *RD);
2525  void layoutNonVirtualBase(const CXXRecordDecl *RD,
2526  const CXXRecordDecl *BaseDecl,
2527  const ASTRecordLayout &BaseLayout,
2528  const ASTRecordLayout *&PreviousBaseLayout);
2529  void injectVFPtr(const CXXRecordDecl *RD);
2530  void injectVBPtr(const CXXRecordDecl *RD);
2531  /// Lays out the fields of the record. Also rounds size up to
2532  /// alignment.
2533  void layoutFields(const RecordDecl *RD);
2534  void layoutField(const FieldDecl *FD);
2535  void layoutBitField(const FieldDecl *FD);
2536  /// Lays out a single zero-width bit-field in the record and handles
2537  /// special cases associated with zero-width bit-fields.
2538  void layoutZeroWidthBitField(const FieldDecl *FD);
2539  void layoutVirtualBases(const CXXRecordDecl *RD);
2540  void finalizeLayout(const RecordDecl *RD);
2541  /// Gets the size and alignment of a base taking pragma pack and
2542  /// __declspec(align) into account.
2543  ElementInfo getAdjustedElementInfo(const ASTRecordLayout &Layout);
2544  /// Gets the size and alignment of a field taking pragma pack and
2545  /// __declspec(align) into account. It also updates RequiredAlignment as a
2546  /// side effect because it is most convenient to do so here.
2547  ElementInfo getAdjustedElementInfo(const FieldDecl *FD);
2548  /// Places a field at an offset in CharUnits.
2549  void placeFieldAtOffset(CharUnits FieldOffset) {
2550  FieldOffsets.push_back(Context.toBits(FieldOffset));
2551  }
2552  /// Places a bitfield at a bit offset.
2553  void placeFieldAtBitOffset(uint64_t FieldOffset) {
2554  FieldOffsets.push_back(FieldOffset);
2555  }
2556  /// Compute the set of virtual bases for which vtordisps are required.
2557  void computeVtorDispSet(
2558  llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtorDispSet,
2559  const CXXRecordDecl *RD) const;
2560  const ASTContext &Context;
2561  /// The size of the record being laid out.
2562  CharUnits Size;
2563  /// The non-virtual size of the record layout.
2564  CharUnits NonVirtualSize;
2565  /// The data size of the record layout.
2566  CharUnits DataSize;
2567  /// The current alignment of the record layout.
2568  CharUnits Alignment;
2569  /// The maximum allowed field alignment. This is set by #pragma pack.
2570  CharUnits MaxFieldAlignment;
2571  /// The alignment that this record must obey. This is imposed by
2572  /// __declspec(align()) on the record itself or one of its fields or bases.
2573  CharUnits RequiredAlignment;
2574  /// The size of the allocation of the currently active bitfield.
2575  /// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield
2576  /// is true.
2577  CharUnits CurrentBitfieldSize;
2578  /// Offset to the virtual base table pointer (if one exists).
2579  CharUnits VBPtrOffset;
2580  /// Minimum record size possible.
2581  CharUnits MinEmptyStructSize;
2582  /// The size and alignment info of a pointer.
2583  ElementInfo PointerInfo;
2584  /// The primary base class (if one exists).
2585  const CXXRecordDecl *PrimaryBase;
2586  /// The class we share our vb-pointer with.
2587  const CXXRecordDecl *SharedVBPtrBase;
2588  /// The collection of field offsets.
2589  SmallVector<uint64_t, 16> FieldOffsets;
2590  /// Base classes and their offsets in the record.
2591  BaseOffsetsMapTy Bases;
2592  /// virtual base classes and their offsets in the record.
2594  /// The number of remaining bits in our last bitfield allocation.
2595  /// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield is
2596  /// true.
2597  unsigned RemainingBitsInField;
2598  bool IsUnion : 1;
2599  /// True if the last field laid out was a bitfield and was not 0
2600  /// width.
2601  bool LastFieldIsNonZeroWidthBitfield : 1;
2602  /// True if the class has its own vftable pointer.
2603  bool HasOwnVFPtr : 1;
2604  /// True if the class has a vbtable pointer.
2605  bool HasVBPtr : 1;
2606  /// True if the last sub-object within the type is zero sized or the
2607  /// object itself is zero sized. This *does not* count members that are not
2608  /// records. Only used for MS-ABI.
2609  bool EndsWithZeroSizedObject : 1;
2610  /// True if this class is zero sized or first base is zero sized or
2611  /// has this property. Only used for MS-ABI.
2612  bool LeadsWithZeroSizedBase : 1;
2613 
2614  /// True if the external AST source provided a layout for this record.
2615  bool UseExternalLayout : 1;
2616 
2617  /// The layout provided by the external AST source. Only active if
2618  /// UseExternalLayout is true.
2619  ExternalLayout External;
2620 };
2621 } // namespace
2622 
2623 MicrosoftRecordLayoutBuilder::ElementInfo
2624 MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
2625  const ASTRecordLayout &Layout) {
2626  ElementInfo Info;
2627  Info.Alignment = Layout.getAlignment();
2628  // Respect pragma pack.
2629  if (!MaxFieldAlignment.isZero())
2630  Info.Alignment = std::min(Info.Alignment, MaxFieldAlignment);
2631  // Track zero-sized subobjects here where it's already available.
2632  EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
2633  // Respect required alignment, this is necessary because we may have adjusted
2634  // the alignment in the case of pragma pack. Note that the required alignment
2635  // doesn't actually apply to the struct alignment at this point.
2636  Alignment = std::max(Alignment, Info.Alignment);
2637  RequiredAlignment = std::max(RequiredAlignment, Layout.getRequiredAlignment());
2638  Info.Alignment = std::max(Info.Alignment, Layout.getRequiredAlignment());
2639  Info.Size = Layout.getNonVirtualSize();
2640  return Info;
2641 }
2642 
2643 MicrosoftRecordLayoutBuilder::ElementInfo
2644 MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
2645  const FieldDecl *FD) {
2646  // Get the alignment of the field type's natural alignment, ignore any
2647  // alignment attributes.
2648  auto TInfo =
2650  ElementInfo Info{TInfo.Width, TInfo.Align};
2651  // Respect align attributes on the field.
2652  CharUnits FieldRequiredAlignment =
2653  Context.toCharUnitsFromBits(FD->getMaxAlignment());
2654  // Respect align attributes on the type.
2655  if (Context.isAlignmentRequired(FD->getType()))
2656  FieldRequiredAlignment = std::max(
2657  Context.getTypeAlignInChars(FD->getType()), FieldRequiredAlignment);
2658  // Respect attributes applied to subobjects of the field.
2659  if (FD->isBitField())
2660  // For some reason __declspec align impacts alignment rather than required
2661  // alignment when it is applied to bitfields.
2662  Info.Alignment = std::max(Info.Alignment, FieldRequiredAlignment);
2663  else {
2664  if (auto RT =
2666  auto const &Layout = Context.getASTRecordLayout(RT->getDecl());
2667  EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
2668  FieldRequiredAlignment = std::max(FieldRequiredAlignment,
2669  Layout.getRequiredAlignment());
2670  }
2671  // Capture required alignment as a side-effect.
2672  RequiredAlignment = std::max(RequiredAlignment, FieldRequiredAlignment);
2673  }
2674  // Respect pragma pack, attribute pack and declspec align
2675  if (!MaxFieldAlignment.isZero())
2676  Info.Alignment = std::min(Info.Alignment, MaxFieldAlignment);
2677  if (FD->hasAttr<PackedAttr>())
2678  Info.Alignment = CharUnits::One();
2679  Info.Alignment = std::max(Info.Alignment, FieldRequiredAlignment);
2680  return Info;
2681 }
2682 
2683 void MicrosoftRecordLayoutBuilder::layout(const RecordDecl *RD) {
2684  // For C record layout, zero-sized records always have size 4.
2685  MinEmptyStructSize = CharUnits::fromQuantity(4);
2686  initializeLayout(RD);
2687  layoutFields(RD);
2688  DataSize = Size = Size.alignTo(Alignment);
2689  RequiredAlignment = std::max(
2690  RequiredAlignment, Context.toCharUnitsFromBits(RD->getMaxAlignment()));
2691  finalizeLayout(RD);
2692 }
2693 
2694 void MicrosoftRecordLayoutBuilder::cxxLayout(const CXXRecordDecl *RD) {
2695  // The C++ standard says that empty structs have size 1.
2696  MinEmptyStructSize = CharUnits::One();
2697  initializeLayout(RD);
2698  initializeCXXLayout(RD);
2699  layoutNonVirtualBases(RD);
2700  layoutFields(RD);
2701  injectVBPtr(RD);
2702  injectVFPtr(RD);
2703  if (HasOwnVFPtr || (HasVBPtr && !SharedVBPtrBase))
2704  Alignment = std::max(Alignment, PointerInfo.Alignment);
2705  auto RoundingAlignment = Alignment;
2706  if (!MaxFieldAlignment.isZero())
2707  RoundingAlignment = std::min(RoundingAlignment, MaxFieldAlignment);
2708  if (!UseExternalLayout)
2709  Size = Size.alignTo(RoundingAlignment);
2710  NonVirtualSize = Size;
2711  RequiredAlignment = std::max(
2712  RequiredAlignment, Context.toCharUnitsFromBits(RD->getMaxAlignment()));
2713  layoutVirtualBases(RD);
2714  finalizeLayout(RD);
2715 }
2716 
2717 void MicrosoftRecordLayoutBuilder::initializeLayout(const RecordDecl *RD) {
2718  IsUnion = RD->isUnion();
2719  Size = CharUnits::Zero();
2720  Alignment = CharUnits::One();
2721  // In 64-bit mode we always perform an alignment step after laying out vbases.
2722  // In 32-bit mode we do not. The check to see if we need to perform alignment
2723  // checks the RequiredAlignment field and performs alignment if it isn't 0.
2724  RequiredAlignment = Context.getTargetInfo().getTriple().isArch64Bit()
2725  ? CharUnits::One()
2726  : CharUnits::Zero();
2727  // Compute the maximum field alignment.
2728  MaxFieldAlignment = CharUnits::Zero();
2729  // Honor the default struct packing maximum alignment flag.
2730  if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct)
2731  MaxFieldAlignment = CharUnits::fromQuantity(DefaultMaxFieldAlignment);
2732  // Honor the packing attribute. The MS-ABI ignores pragma pack if its larger
2733  // than the pointer size.
2734  if (const MaxFieldAlignmentAttr *MFAA = RD->getAttr<MaxFieldAlignmentAttr>()){
2735  unsigned PackedAlignment = MFAA->getAlignment();
2736  if (PackedAlignment <= Context.getTargetInfo().getPointerWidth(0))
2737  MaxFieldAlignment = Context.toCharUnitsFromBits(PackedAlignment);
2738  }
2739  // Packed attribute forces max field alignment to be 1.
2740  if (RD->hasAttr<PackedAttr>())
2741  MaxFieldAlignment = CharUnits::One();
2742 
2743  // Try to respect the external layout if present.
2744  UseExternalLayout = false;
2745  if (ExternalASTSource *Source = Context.getExternalSource())
2746  UseExternalLayout = Source->layoutRecordType(
2747  RD, External.Size, External.Align, External.FieldOffsets,
2748  External.BaseOffsets, External.VirtualBaseOffsets);
2749 }
2750 
2751 void
2752 MicrosoftRecordLayoutBuilder::initializeCXXLayout(const CXXRecordDecl *RD) {
2753  EndsWithZeroSizedObject = false;
2754  LeadsWithZeroSizedBase = false;
2755  HasOwnVFPtr = false;
2756  HasVBPtr = false;
2757  PrimaryBase = nullptr;
2758  SharedVBPtrBase = nullptr;
2759  // Calculate pointer size and alignment. These are used for vfptr and vbprt
2760  // injection.
2761  PointerInfo.Size =
2762  Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
2763  PointerInfo.Alignment =
2764  Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(0));
2765  // Respect pragma pack.
2766  if (!MaxFieldAlignment.isZero())
2767  PointerInfo.Alignment = std::min(PointerInfo.Alignment, MaxFieldAlignment);
2768 }
2769 
2770 void
2771 MicrosoftRecordLayoutBuilder::layoutNonVirtualBases(const CXXRecordDecl *RD) {
2772  // The MS-ABI lays out all bases that contain leading vfptrs before it lays
2773  // out any bases that do not contain vfptrs. We implement this as two passes
2774  // over the bases. This approach guarantees that the primary base is laid out
2775  // first. We use these passes to calculate some additional aggregated
2776  // information about the bases, such as required alignment and the presence of
2777  // zero sized members.
2778  const ASTRecordLayout *PreviousBaseLayout = nullptr;
2779  bool HasPolymorphicBaseClass = false;
2780  // Iterate through the bases and lay out the non-virtual ones.
2781  for (const CXXBaseSpecifier &Base : RD->bases()) {
2782  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2783  HasPolymorphicBaseClass |= BaseDecl->isPolymorphic();
2784  const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2785  // Mark and skip virtual bases.
2786  if (Base.isVirtual()) {
2787  HasVBPtr = true;
2788  continue;
2789  }
2790  // Check for a base to share a VBPtr with.
2791  if (!SharedVBPtrBase && BaseLayout.hasVBPtr()) {
2792  SharedVBPtrBase = BaseDecl;
2793  HasVBPtr = true;
2794  }
2795  // Only lay out bases with extendable VFPtrs on the first pass.
2796  if (!BaseLayout.hasExtendableVFPtr())
2797  continue;
2798  // If we don't have a primary base, this one qualifies.
2799  if (!PrimaryBase) {
2800  PrimaryBase = BaseDecl;
2801  LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
2802  }
2803  // Lay out the base.
2804  layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
2805  }
2806  // Figure out if we need a fresh VFPtr for this class.
2807  if (RD->isPolymorphic()) {
2808  if (!HasPolymorphicBaseClass)
2809  // This class introduces polymorphism, so we need a vftable to store the
2810  // RTTI information.
2811  HasOwnVFPtr = true;
2812  else if (!PrimaryBase) {
2813  // We have a polymorphic base class but can't extend its vftable. Add a
2814  // new vfptr if we would use any vftable slots.
2815  for (CXXMethodDecl *M : RD->methods()) {
2817  M->size_overridden_methods() == 0) {
2818  HasOwnVFPtr = true;
2819  break;
2820  }
2821  }
2822  }
2823  }
2824  // If we don't have a primary base then we have a leading object that could
2825  // itself lead with a zero-sized object, something we track.
2826  bool CheckLeadingLayout = !PrimaryBase;
2827  // Iterate through the bases and lay out the non-virtual ones.
2828  for (const CXXBaseSpecifier &Base : RD->bases()) {
2829  if (Base.isVirtual())
2830  continue;
2831  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2832  const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2833  // Only lay out bases without extendable VFPtrs on the second pass.
2834  if (BaseLayout.hasExtendableVFPtr()) {
2835  VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
2836  continue;
2837  }
2838  // If this is the first layout, check to see if it leads with a zero sized
2839  // object. If it does, so do we.
2840  if (CheckLeadingLayout) {
2841  CheckLeadingLayout = false;
2842  LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
2843  }
2844  // Lay out the base.
2845  layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
2846  VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
2847  }
2848  // Set our VBPtroffset if we know it at this point.
2849  if (!HasVBPtr)
2850  VBPtrOffset = CharUnits::fromQuantity(-1);
2851  else if (SharedVBPtrBase) {
2852  const ASTRecordLayout &Layout = Context.getASTRecordLayout(SharedVBPtrBase);
2853  VBPtrOffset = Bases[SharedVBPtrBase] + Layout.getVBPtrOffset();
2854  }
2855 }
2856 
2857 static bool recordUsesEBO(const RecordDecl *RD) {
2858  if (!isa<CXXRecordDecl>(RD))
2859  return false;
2860  if (RD->hasAttr<EmptyBasesAttr>())
2861  return true;
2862  if (auto *LVA = RD->getAttr<LayoutVersionAttr>())
2863  // TODO: Double check with the next version of MSVC.
2864  if (LVA->getVersion() <= LangOptions::MSVC2015)
2865  return false;
2866  // TODO: Some later version of MSVC will change the default behavior of the
2867  // compiler to enable EBO by default. When this happens, we will need an
2868  // additional isCompatibleWithMSVC check.
2869  return false;
2870 }
2871 
2872 void MicrosoftRecordLayoutBuilder::layoutNonVirtualBase(
2873  const CXXRecordDecl *RD,
2874  const CXXRecordDecl *BaseDecl,
2875  const ASTRecordLayout &BaseLayout,
2876  const ASTRecordLayout *&PreviousBaseLayout) {
2877  // Insert padding between two bases if the left first one is zero sized or
2878  // contains a zero sized subobject and the right is zero sized or one leads
2879  // with a zero sized base.
2880  bool MDCUsesEBO = recordUsesEBO(RD);
2881  if (PreviousBaseLayout && PreviousBaseLayout->endsWithZeroSizedObject() &&
2882  BaseLayout.leadsWithZeroSizedBase() && !MDCUsesEBO)
2883  Size++;
2884  ElementInfo Info = getAdjustedElementInfo(BaseLayout);
2885  CharUnits BaseOffset;
2886 
2887  // Respect the external AST source base offset, if present.
2888  bool FoundBase = false;
2889  if (UseExternalLayout) {
2890  FoundBase = External.getExternalNVBaseOffset(BaseDecl, BaseOffset);
2891  if (FoundBase) {
2892  assert(BaseOffset >= Size && "base offset already allocated");
2893  Size = BaseOffset;
2894  }
2895  }
2896 
2897  if (!FoundBase) {
2898  if (MDCUsesEBO && BaseDecl->isEmpty()) {
2899  assert(BaseLayout.getNonVirtualSize() == CharUnits::Zero());
2900  BaseOffset = CharUnits::Zero();
2901  } else {
2902  // Otherwise, lay the base out at the end of the MDC.
2903  BaseOffset = Size = Size.alignTo(Info.Alignment);
2904  }
2905  }
2906  Bases.insert(std::make_pair(BaseDecl, BaseOffset));
2907  Size += BaseLayout.getNonVirtualSize();
2908  PreviousBaseLayout = &BaseLayout;
2909 }
2910 
2911 void MicrosoftRecordLayoutBuilder::layoutFields(const RecordDecl *RD) {
2912  LastFieldIsNonZeroWidthBitfield = false;
2913  for (const FieldDecl *Field : RD->fields())
2914  layoutField(Field);
2915 }
2916 
2917 void MicrosoftRecordLayoutBuilder::layoutField(const FieldDecl *FD) {
2918  if (FD->isBitField()) {
2919  layoutBitField(FD);
2920  return;
2921  }
2922  LastFieldIsNonZeroWidthBitfield = false;
2923  ElementInfo Info = getAdjustedElementInfo(FD);
2924  Alignment = std::max(Alignment, Info.Alignment);
2925  CharUnits FieldOffset;
2926  if (UseExternalLayout)
2927  FieldOffset =
2928  Context.toCharUnitsFromBits(External.getExternalFieldOffset(FD));
2929  else if (IsUnion)
2930  FieldOffset = CharUnits::Zero();
2931  else
2932  FieldOffset = Size.alignTo(Info.Alignment);
2933  placeFieldAtOffset(FieldOffset);
2934  Size = std::max(Size, FieldOffset + Info.Size);
2935 }
2936 
2937 void MicrosoftRecordLayoutBuilder::layoutBitField(const FieldDecl *FD) {
2938  unsigned Width = FD->getBitWidthValue(Context);
2939  if (Width == 0) {
2940  layoutZeroWidthBitField(FD);
2941  return;
2942  }
2943  ElementInfo Info = getAdjustedElementInfo(FD);
2944  // Clamp the bitfield to a containable size for the sake of being able
2945  // to lay them out. Sema will throw an error.
2946  if (Width > Context.toBits(Info.Size))
2947  Width = Context.toBits(Info.Size);
2948  // Check to see if this bitfield fits into an existing allocation. Note:
2949  // MSVC refuses to pack bitfields of formal types with different sizes
2950  // into the same allocation.
2951  if (!UseExternalLayout && !IsUnion && LastFieldIsNonZeroWidthBitfield &&
2952  CurrentBitfieldSize == Info.Size && Width <= RemainingBitsInField) {
2953  placeFieldAtBitOffset(Context.toBits(Size) - RemainingBitsInField);
2954  RemainingBitsInField -= Width;
2955  return;
2956  }
2957  LastFieldIsNonZeroWidthBitfield = true;
2958  CurrentBitfieldSize = Info.Size;
2959  if (UseExternalLayout) {
2960  auto FieldBitOffset = External.getExternalFieldOffset(FD);
2961  placeFieldAtBitOffset(FieldBitOffset);
2962  auto NewSize = Context.toCharUnitsFromBits(
2963  llvm::alignDown(FieldBitOffset, Context.toBits(Info.Alignment)) +
2964  Context.toBits(Info.Size));
2965  Size = std::max(Size, NewSize);
2966  Alignment = std::max(Alignment, Info.Alignment);
2967  } else if (IsUnion) {
2968  placeFieldAtOffset(CharUnits::Zero());
2969  Size = std::max(Size, Info.Size);
2970  // TODO: Add a Sema warning that MS ignores bitfield alignment in unions.
2971  } else {
2972  // Allocate a new block of memory and place the bitfield in it.
2973  CharUnits FieldOffset = Size.alignTo(Info.Alignment);
2974  placeFieldAtOffset(FieldOffset);
2975  Size = FieldOffset + Info.Size;
2976  Alignment = std::max(Alignment, Info.Alignment);
2977  RemainingBitsInField = Context.toBits(Info.Size) - Width;
2978  }
2979 }
2980 
2981 void
2982 MicrosoftRecordLayoutBuilder::layoutZeroWidthBitField(const FieldDecl *FD) {
2983  // Zero-width bitfields are ignored unless they follow a non-zero-width
2984  // bitfield.
2985  if (!LastFieldIsNonZeroWidthBitfield) {
2986  placeFieldAtOffset(IsUnion ? CharUnits::Zero() : Size);
2987  // TODO: Add a Sema warning that MS ignores alignment for zero
2988  // sized bitfields that occur after zero-size bitfields or non-bitfields.
2989  return;
2990  }
2991  LastFieldIsNonZeroWidthBitfield = false;
2992  ElementInfo Info = getAdjustedElementInfo(FD);
2993  if (IsUnion) {
2994  placeFieldAtOffset(CharUnits::Zero());
2995  Size = std::max(Size, Info.Size);
2996  // TODO: Add a Sema warning that MS ignores bitfield alignment in unions.
2997  } else {
2998  // Round up the current record size to the field's alignment boundary.
2999  CharUnits FieldOffset = Size.alignTo(Info.Alignment);
3000  placeFieldAtOffset(FieldOffset);
3001  Size = FieldOffset;
3002  Alignment = std::max(Alignment, Info.Alignment);
3003  }
3004 }
3005 
3006 void MicrosoftRecordLayoutBuilder::injectVBPtr(const CXXRecordDecl *RD) {
3007  if (!HasVBPtr || SharedVBPtrBase)
3008  return;
3009  // Inject the VBPointer at the injection site.
3010  CharUnits InjectionSite = VBPtrOffset;
3011  // But before we do, make sure it's properly aligned.
3012  VBPtrOffset = VBPtrOffset.alignTo(PointerInfo.Alignment);
3013  // Determine where the first field should be laid out after the vbptr.
3014  CharUnits FieldStart = VBPtrOffset + PointerInfo.Size;
3015  // Shift everything after the vbptr down, unless we're using an external
3016  // layout.
3017  if (UseExternalLayout) {
3018  // It is possible that there were no fields or bases located after vbptr,
3019  // so the size was not adjusted before.
3020  if (Size < FieldStart)
3021  Size = FieldStart;
3022  return;
3023  }
3024  // Make sure that the amount we push the fields back by is a multiple of the
3025  // alignment.
3026  CharUnits Offset = (FieldStart - InjectionSite)
3027  .alignTo(std::max(RequiredAlignment, Alignment));
3028  Size += Offset;
3029  for (uint64_t &FieldOffset : FieldOffsets)
3030  FieldOffset += Context.toBits(Offset);
3031  for (BaseOffsetsMapTy::value_type &Base : Bases)
3032  if (Base.second >= InjectionSite)
3033  Base.second += Offset;
3034 }
3035 
3036 void MicrosoftRecordLayoutBuilder::injectVFPtr(const CXXRecordDecl *RD) {
3037  if (!HasOwnVFPtr)
3038  return;
3039  // Make sure that the amount we push the struct back by is a multiple of the
3040  // alignment.
3041  CharUnits Offset =
3042  PointerInfo.Size.alignTo(std::max(RequiredAlignment, Alignment));
3043  // Push back the vbptr, but increase the size of the object and push back
3044  // regular fields by the offset only if not using external record layout.
3045  if (HasVBPtr)
3046  VBPtrOffset += Offset;
3047 
3048  if (UseExternalLayout) {
3049  // The class may have no bases or fields, but still have a vfptr
3050  // (e.g. it's an interface class). The size was not correctly set before
3051  // in this case.
3052  if (FieldOffsets.empty() && Bases.empty())
3053  Size += Offset;
3054  return;
3055  }
3056 
3057  Size += Offset;
3058 
3059  // If we're using an external layout, the fields offsets have already
3060  // accounted for this adjustment.
3061  for (uint64_t &FieldOffset : FieldOffsets)
3062  FieldOffset += Context.toBits(Offset);
3063  for (BaseOffsetsMapTy::value_type &Base : Bases)
3064  Base.second += Offset;
3065 }
3066 
3067 void MicrosoftRecordLayoutBuilder::layoutVirtualBases(const CXXRecordDecl *RD) {
3068  if (!HasVBPtr)
3069  return;
3070  // Vtordisps are always 4 bytes (even in 64-bit mode)
3071  CharUnits VtorDispSize = CharUnits::fromQuantity(4);
3072  CharUnits VtorDispAlignment = VtorDispSize;
3073  // vtordisps respect pragma pack.
3074  if (!MaxFieldAlignment.isZero())
3075  VtorDispAlignment = std::min(VtorDispAlignment, MaxFieldAlignment);
3076  // The alignment of the vtordisp is at least the required alignment of the
3077  // entire record. This requirement may be present to support vtordisp
3078  // injection.
3079  for (const CXXBaseSpecifier &VBase : RD->vbases()) {
3080  const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
3081  const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
3082  RequiredAlignment =
3083  std::max(RequiredAlignment, BaseLayout.getRequiredAlignment());
3084  }
3085  VtorDispAlignment = std::max(VtorDispAlignment, RequiredAlignment);
3086  // Compute the vtordisp set.
3088  computeVtorDispSet(HasVtorDispSet, RD);
3089  // Iterate through the virtual bases and lay them out.
3090  const ASTRecordLayout *PreviousBaseLayout = nullptr;
3091  for (const CXXBaseSpecifier &VBase : RD->vbases()) {
3092  const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
3093  const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
3094  bool HasVtordisp = HasVtorDispSet.count(BaseDecl) > 0;
3095  // Insert padding between two bases if the left first one is zero sized or
3096  // contains a zero sized subobject and the right is zero sized or one leads
3097  // with a zero sized base. The padding between virtual bases is 4
3098  // bytes (in both 32 and 64 bits modes) and always involves rounding up to
3099  // the required alignment, we don't know why.
3100  if ((PreviousBaseLayout && PreviousBaseLayout->endsWithZeroSizedObject() &&
3101  BaseLayout.leadsWithZeroSizedBase() && !recordUsesEBO(RD)) ||
3102  HasVtordisp) {
3103  Size = Size.alignTo(VtorDispAlignment) + VtorDispSize;
3104  Alignment = std::max(VtorDispAlignment, Alignment);
3105  }
3106  // Insert the virtual base.
3107  ElementInfo Info = getAdjustedElementInfo(BaseLayout);
3108  CharUnits BaseOffset;
3109 
3110  // Respect the external AST source base offset, if present.
3111  if (UseExternalLayout) {
3112  if (!External.getExternalVBaseOffset(BaseDecl, BaseOffset))
3113  BaseOffset = Size;
3114  } else
3115  BaseOffset = Size.alignTo(Info.Alignment);
3116 
3117  assert(BaseOffset >= Size && "base offset already allocated");
3118 
3119  VBases.insert(std::make_pair(BaseDecl,
3120  ASTRecordLayout::VBaseInfo(BaseOffset, HasVtordisp)));
3121  Size = BaseOffset + BaseLayout.getNonVirtualSize();
3122  PreviousBaseLayout = &BaseLayout;
3123  }
3124 }
3125 
3126 void MicrosoftRecordLayoutBuilder::finalizeLayout(const RecordDecl *RD) {
3127  // Respect required alignment. Note that in 32-bit mode Required alignment
3128  // may be 0 and cause size not to be updated.
3129  DataSize = Size;
3130  if (!RequiredAlignment.isZero()) {
3131  Alignment = std::max(Alignment, RequiredAlignment);
3132  auto RoundingAlignment = Alignment;
3133  if (!MaxFieldAlignment.isZero())
3134  RoundingAlignment = std::min(RoundingAlignment, MaxFieldAlignment);
3135  RoundingAlignment = std::max(RoundingAlignment, RequiredAlignment);
3136  Size = Size.alignTo(RoundingAlignment);
3137  }
3138  if (Size.isZero()) {
3139  if (!recordUsesEBO(RD) || !cast<CXXRecordDecl>(RD)->isEmpty()) {
3140  EndsWithZeroSizedObject = true;
3141  LeadsWithZeroSizedBase = true;
3142  }
3143  // Zero-sized structures have size equal to their alignment if a
3144  // __declspec(align) came into play.
3145  if (RequiredAlignment >= MinEmptyStructSize)
3146  Size = Alignment;
3147  else
3148  Size = MinEmptyStructSize;
3149  }
3150 
3151  if (UseExternalLayout) {
3152  Size = Context.toCharUnitsFromBits(External.Size);
3153  if (External.Align)
3154  Alignment = Context.toCharUnitsFromBits(External.Align);
3155  }
3156 }
3157 
3158 // Recursively walks the non-virtual bases of a class and determines if any of
3159 // them are in the bases with overridden methods set.
3160 static bool
3161 RequiresVtordisp(const llvm::SmallPtrSetImpl<const CXXRecordDecl *> &
3162  BasesWithOverriddenMethods,
3163  const CXXRecordDecl *RD) {
3164  if (BasesWithOverriddenMethods.count(RD))
3165  return true;
3166  // If any of a virtual bases non-virtual bases (recursively) requires a
3167  // vtordisp than so does this virtual base.
3168  for (const CXXBaseSpecifier &Base : RD->bases())
3169  if (!Base.isVirtual() &&
3170  RequiresVtordisp(BasesWithOverriddenMethods,
3171  Base.getType()->getAsCXXRecordDecl()))
3172  return true;
3173  return false;
3174 }
3175 
3176 void MicrosoftRecordLayoutBuilder::computeVtorDispSet(
3177  llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtordispSet,
3178  const CXXRecordDecl *RD) const {
3179  // /vd2 or #pragma vtordisp(2): Always use vtordisps for virtual bases with
3180  // vftables.
3182  for (const CXXBaseSpecifier &Base : RD->vbases()) {
3183  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
3184  const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
3185  if (Layout.hasExtendableVFPtr())
3186  HasVtordispSet.insert(BaseDecl);
3187  }
3188  return;
3189  }
3190 
3191  // If any of our bases need a vtordisp for this type, so do we. Check our
3192  // direct bases for vtordisp requirements.
3193  for (const CXXBaseSpecifier &Base : RD->bases()) {
3194  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
3195  const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
3196  for (const auto &bi : Layout.getVBaseOffsetsMap())
3197  if (bi.second.hasVtorDisp())
3198  HasVtordispSet.insert(bi.first);
3199  }
3200  // We don't introduce any additional vtordisps if either:
3201  // * A user declared constructor or destructor aren't declared.
3202  // * #pragma vtordisp(0) or the /vd0 flag are in use.
3203  if ((!RD->hasUserDeclaredConstructor() && !RD->hasUserDeclaredDestructor()) ||
3205  return;
3206  // /vd1 or #pragma vtordisp(1): Try to guess based on whether we think it's
3207  // possible for a partially constructed object with virtual base overrides to
3208  // escape a non-trivial constructor.
3210  // Compute a set of base classes which define methods we override. A virtual
3211  // base in this set will require a vtordisp. A virtual base that transitively
3212  // contains one of these bases as a non-virtual base will also require a
3213  // vtordisp.
3215  llvm::SmallPtrSet<const CXXRecordDecl *, 2> BasesWithOverriddenMethods;
3216  // Seed the working set with our non-destructor, non-pure virtual methods.
3217  for (const CXXMethodDecl *MD : RD->methods())
3219  !isa<CXXDestructorDecl>(MD) && !MD->isPure())
3220  Work.insert(MD);
3221  while (!Work.empty()) {
3222  const CXXMethodDecl *MD = *Work.begin();
3223  auto MethodRange = MD->overridden_methods();
3224  // If a virtual method has no-overrides it lives in its parent's vtable.
3225  if (MethodRange.begin() == MethodRange.end())
3226  BasesWithOverriddenMethods.insert(MD->getParent());
3227  else
3228  Work.insert(MethodRange.begin(), MethodRange.end());
3229  // We've finished processing this element, remove it from the working set.
3230  Work.erase(MD);
3231  }
3232  // For each of our virtual bases, check if it is in the set of overridden
3233  // bases or if it transitively contains a non-virtual base that is.
3234  for (const CXXBaseSpecifier &Base : RD->vbases()) {
3235  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
3236  if (!HasVtordispSet.count(BaseDecl) &&
3237  RequiresVtordisp(BasesWithOverriddenMethods, BaseDecl))
3238  HasVtordispSet.insert(BaseDecl);
3239  }
3240 }
3241 
3242 /// getASTRecordLayout - Get or compute information about the layout of the
3243 /// specified record (struct/union/class), which indicates its size and field
3244 /// position information.
3245 const ASTRecordLayout &
3247  // These asserts test different things. A record has a definition
3248  // as soon as we begin to parse the definition. That definition is
3249  // not a complete definition (which is what isDefinition() tests)
3250  // until we *finish* parsing the definition.
3251 
3252  if (D->hasExternalLexicalStorage() && !D->getDefinition())
3253  getExternalSource()->CompleteType(const_cast<RecordDecl*>(D));
3254 
3255  D = D->getDefinition();
3256  assert(D && "Cannot get layout of forward declarations!");
3257  assert(!D->isInvalidDecl() && "Cannot get layout of invalid decl!");
3258  assert(D->isCompleteDefinition() && "Cannot layout type before complete!");
3259 
3260  // Look up this layout, if already laid out, return what we have.
3261  // Note that we can't save a reference to the entry because this function
3262  // is recursive.
3263  const ASTRecordLayout *Entry = ASTRecordLayouts[D];
3264  if (Entry) return *Entry;
3265 
3266  const ASTRecordLayout *NewEntry = nullptr;
3267 
3268  if (isMsLayout(*this)) {
3269  MicrosoftRecordLayoutBuilder Builder(*this);
3270  if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
3271  Builder.cxxLayout(RD);
3272  NewEntry = new (*this) ASTRecordLayout(
3273  *this, Builder.Size, Builder.Alignment, Builder.Alignment,
3274  Builder.Alignment, Builder.RequiredAlignment, Builder.HasOwnVFPtr,
3275  Builder.HasOwnVFPtr || Builder.PrimaryBase, Builder.VBPtrOffset,
3276  Builder.DataSize, Builder.FieldOffsets, Builder.NonVirtualSize,
3277  Builder.Alignment, Builder.Alignment, CharUnits::Zero(),
3278  Builder.PrimaryBase, false, Builder.SharedVBPtrBase,
3279  Builder.EndsWithZeroSizedObject, Builder.LeadsWithZeroSizedBase,
3280  Builder.Bases, Builder.VBases);
3281  } else {
3282  Builder.layout(D);
3283  NewEntry = new (*this) ASTRecordLayout(
3284  *this, Builder.Size, Builder.Alignment, Builder.Alignment,
3285  Builder.Alignment, Builder.RequiredAlignment, Builder.Size,
3286  Builder.FieldOffsets);
3287  }
3288  } else {
3289  if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
3290  EmptySubobjectMap EmptySubobjects(*this, RD);
3291  ItaniumRecordLayoutBuilder Builder(*this, &EmptySubobjects);
3292  Builder.Layout(RD);
3293 
3294  // In certain situations, we are allowed to lay out objects in the
3295  // tail-padding of base classes. This is ABI-dependent.
3296  // FIXME: this should be stored in the record layout.
3297  bool skipTailPadding =
3298  mustSkipTailPadding(getTargetInfo().getCXXABI(), RD);
3299 
3300  // FIXME: This should be done in FinalizeLayout.
3301  CharUnits DataSize =
3302  skipTailPadding ? Builder.getSize() : Builder.getDataSize();
3303  CharUnits NonVirtualSize =
3304  skipTailPadding ? DataSize : Builder.NonVirtualSize;
3305  NewEntry = new (*this) ASTRecordLayout(
3306  *this, Builder.getSize(), Builder.Alignment,
3307  Builder.PreferredAlignment, Builder.UnadjustedAlignment,
3308  /*RequiredAlignment : used by MS-ABI)*/
3309  Builder.Alignment, Builder.HasOwnVFPtr, RD->isDynamicClass(),
3310  CharUnits::fromQuantity(-1), DataSize, Builder.FieldOffsets,
3311  NonVirtualSize, Builder.NonVirtualAlignment,
3312  Builder.PreferredNVAlignment,
3313  EmptySubobjects.SizeOfLargestEmptySubobject, Builder.PrimaryBase,
3314  Builder.PrimaryBaseIsVirtual, nullptr, false, false, Builder.Bases,
3315  Builder.VBases);
3316  } else {
3317  ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3318  Builder.Layout(D);
3319 
3320  NewEntry = new (*this) ASTRecordLayout(
3321  *this, Builder.getSize(), Builder.Alignment,
3322  Builder.PreferredAlignment, Builder.UnadjustedAlignment,
3323  /*RequiredAlignment : used by MS-ABI)*/
3324  Builder.Alignment, Builder.getSize(), Builder.FieldOffsets);
3325  }
3326  }
3327 
3328  ASTRecordLayouts[D] = NewEntry;
3329 
3330  if (getLangOpts().DumpRecordLayouts) {
3331  llvm::outs() << "\n*** Dumping AST Record Layout\n";
3332  DumpRecordLayout(D, llvm::outs(), getLangOpts().DumpRecordLayoutsSimple);
3333  }
3334 
3335  return *NewEntry;
3336 }
3337 
3339  if (!getTargetInfo().getCXXABI().hasKeyFunctions())
3340  return nullptr;
3341 
3342  assert(RD->getDefinition() && "Cannot get key function for forward decl!");
3343  RD = RD->getDefinition();
3344 
3345  // Beware:
3346  // 1) computing the key function might trigger deserialization, which might
3347  // invalidate iterators into KeyFunctions
3348  // 2) 'get' on the LazyDeclPtr might also trigger deserialization and
3349  // invalidate the LazyDeclPtr within the map itself
3350  LazyDeclPtr Entry = KeyFunctions[RD];
3351  const Decl *Result =
3352  Entry ? Entry.get(getExternalSource()) : computeKeyFunction(*this, RD);
3353 
3354  // Store it back if it changed.
3355  if (Entry.isOffset() || Entry.isValid() != bool(Result))
3356  KeyFunctions[RD] = const_cast<Decl*>(Result);
3357 
3358  return cast_or_null<CXXMethodDecl>(Result);
3359 }
3360 
3362  assert(Method == Method->getFirstDecl() &&
3363  "not working with method declaration from class definition");
3364 
3365  // Look up the cache entry. Since we're working with the first
3366  // declaration, its parent must be the class definition, which is
3367  // the correct key for the KeyFunctions hash.
3368  const auto &Map = KeyFunctions;
3369  auto I = Map.find(Method->getParent());
3370 
3371  // If it's not cached, there's nothing to do.
3372  if (I == Map.end()) return;
3373 
3374  // If it is cached, check whether it's the target method, and if so,
3375  // remove it from the cache. Note, the call to 'get' might invalidate
3376  // the iterator and the LazyDeclPtr object within the map.
3377  LazyDeclPtr Ptr = I->second;
3378  if (Ptr.get(getExternalSource()) == Method) {
3379  // FIXME: remember that we did this for module / chained PCH state?
3380  KeyFunctions.erase(Method->getParent());
3381  }
3382 }
3383 
3384 static uint64_t getFieldOffset(const ASTContext &C, const FieldDecl *FD) {
3385  const ASTRecordLayout &Layout = C.getASTRecordLayout(FD->getParent());
3386  return Layout.getFieldOffset(FD->getFieldIndex());
3387 }
3388 
3389 uint64_t ASTContext::getFieldOffset(const ValueDecl *VD) const {
3390  uint64_t OffsetInBits;
3391  if (const FieldDecl *FD = dyn_cast<FieldDecl>(VD)) {
3392  OffsetInBits = ::getFieldOffset(*this, FD);
3393  } else {
3394  const IndirectFieldDecl *IFD = cast<IndirectFieldDecl>(VD);
3395 
3396  OffsetInBits = 0;
3397  for (const NamedDecl *ND : IFD->chain())
3398  OffsetInBits += ::getFieldOffset(*this, cast<FieldDecl>(ND));
3399  }
3400 
3401  return OffsetInBits;
3402 }
3403 
3405  const ObjCImplementationDecl *ID,
3406  const ObjCIvarDecl *Ivar) const {
3407  Ivar = Ivar->getCanonicalDecl();
3408  const ObjCInterfaceDecl *Container = Ivar->getContainingInterface();
3409 
3410  // FIXME: We should eliminate the need to have ObjCImplementationDecl passed
3411  // in here; it should never be necessary because that should be the lexical
3412  // decl context for the ivar.
3413 
3414  // If we know have an implementation (and the ivar is in it) then
3415  // look up in the implementation layout.
3416  const ASTRecordLayout *RL;
3417  if (ID && declaresSameEntity(ID->getClassInterface(), Container))
3419  else
3420  RL = &getASTObjCInterfaceLayout(Container);
3421 
3422  // Compute field index.
3423  //
3424  // FIXME: The index here is closely tied to how ASTContext::getObjCLayout is
3425  // implemented. This should be fixed to get the information from the layout
3426  // directly.
3427  unsigned Index = 0;
3428 
3429  for (const ObjCIvarDecl *IVD = Container->all_declared_ivar_begin();
3430  IVD; IVD = IVD->getNextIvar()) {
3431  if (Ivar == IVD)
3432  break;
3433  ++Index;
3434  }
3435  assert(Index < RL->getFieldCount() && "Ivar is not inside record layout!");
3436 
3437  return RL->getFieldOffset(Index);
3438 }
3439 
3440 /// getObjCLayout - Get or compute information about the layout of the
3441 /// given interface.
3442 ///
3443 /// \param Impl - If given, also include the layout of the interface's
3444 /// implementation. This may differ by including synthesized ivars.
3445 const ASTRecordLayout &
3446 ASTContext::getObjCLayout(const ObjCInterfaceDecl *D,
3447  const ObjCImplementationDecl *Impl) const {
3448  // Retrieve the definition
3449  if (D->hasExternalLexicalStorage() && !D->getDefinition())
3450  getExternalSource()->CompleteType(const_cast<ObjCInterfaceDecl*>(D));
3451  D = D->getDefinition();
3452  assert(D && !D->isInvalidDecl() && D->isThisDeclarationADefinition() &&
3453  "Invalid interface decl!");
3454 
3455  // Look up this layout, if already laid out, return what we have.
3456  const ObjCContainerDecl *Key =
3457  Impl ? (const ObjCContainerDecl*) Impl : (const ObjCContainerDecl*) D;
3458  if (const ASTRecordLayout *Entry = ObjCLayouts[Key])
3459  return *Entry;
3460 
3461  // Add in synthesized ivar count if laying out an implementation.
3462  if (Impl) {
3463  unsigned SynthCount = CountNonClassIvars(D);
3464  // If there aren't any synthesized ivars then reuse the interface
3465  // entry. Note we can't cache this because we simply free all
3466  // entries later; however we shouldn't look up implementations
3467  // frequently.
3468  if (SynthCount == 0)
3469  return getObjCLayout(D, nullptr);
3470  }
3471 
3472  ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3473  Builder.Layout(D);
3474 
3475  const ASTRecordLayout *NewEntry = new (*this) ASTRecordLayout(
3476  *this, Builder.getSize(), Builder.Alignment, Builder.PreferredAlignment,
3477  Builder.UnadjustedAlignment,
3478  /*RequiredAlignment : used by MS-ABI)*/
3479  Builder.Alignment, Builder.getDataSize(), Builder.FieldOffsets);
3480 
3481  ObjCLayouts[Key] = NewEntry;
3482 
3483  return *NewEntry;
3484 }
3485 
3486 static void PrintOffset(raw_ostream &OS,
3487  CharUnits Offset, unsigned IndentLevel) {
3488  OS << llvm::format("%10" PRId64 " | ", (int64_t)Offset.getQuantity());
3489  OS.indent(IndentLevel * 2);
3490 }
3491 
3492 static void PrintBitFieldOffset(raw_ostream &OS, CharUnits Offset,
3493  unsigned Begin, unsigned Width,
3494  unsigned IndentLevel) {
3495  llvm::SmallString<10> Buffer;
3496  {
3497  llvm::raw_svector_ostream BufferOS(Buffer);
3498  BufferOS << Offset.getQuantity() << ':';
3499  if (Width == 0) {
3500  BufferOS << '-';
3501  } else {
3502  BufferOS << Begin << '-' << (Begin + Width - 1);
3503  }
3504  }
3505 
3506  OS << llvm::right_justify(Buffer, 10) << " | ";
3507  OS.indent(IndentLevel * 2);
3508 }
3509 
3510 static void PrintIndentNoOffset(raw_ostream &OS, unsigned IndentLevel) {
3511  OS << " | ";
3512  OS.indent(IndentLevel * 2);
3513 }
3514 
3515 static void DumpRecordLayout(raw_ostream &OS, const RecordDecl *RD,
3516  const ASTContext &C,
3517  CharUnits Offset,
3518  unsigned IndentLevel,
3519  const char* Description,
3520  bool PrintSizeInfo,
3521  bool IncludeVirtualBases) {
3522  const ASTRecordLayout &Layout = C.getASTRecordLayout(RD);
3523  auto CXXRD = dyn_cast<CXXRecordDecl>(RD);
3524 
3525  PrintOffset(OS, Offset, IndentLevel);
3526  OS << C.getTypeDeclType(const_cast<RecordDecl*>(RD)).getAsString();
3527  if (Description)
3528  OS << ' ' << Description;
3529  if (CXXRD && CXXRD->isEmpty())
3530  OS << " (empty)";
3531  OS << '\n';
3532 
3533  IndentLevel++;
3534 
3535  // Dump bases.
3536  if (CXXRD) {
3537  const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
3538  bool HasOwnVFPtr = Layout.hasOwnVFPtr();
3539  bool HasOwnVBPtr = Layout.hasOwnVBPtr();
3540 
3541  // Vtable pointer.
3542  if (CXXRD->isDynamicClass() && !PrimaryBase && !isMsLayout(C)) {
3543  PrintOffset(OS, Offset, IndentLevel);
3544  OS << '(' << *RD << " vtable pointer)\n";
3545  } else if (HasOwnVFPtr) {
3546  PrintOffset(OS, Offset, IndentLevel);
3547  // vfptr (for Microsoft C++ ABI)
3548  OS << '(' << *RD << " vftable pointer)\n";
3549  }
3550 
3551  // Collect nvbases.
3553  for (const CXXBaseSpecifier &Base : CXXRD->bases()) {
3554  assert(!Base.getType()->isDependentType() &&
3555  "Cannot layout class with dependent bases.");
3556  if (!Base.isVirtual())
3557  Bases.push_back(Base.getType()->getAsCXXRecordDecl());
3558  }
3559 
3560  // Sort nvbases by offset.
3561  llvm::stable_sort(
3562  Bases, [&](const CXXRecordDecl *L, const CXXRecordDecl *R) {
3563  return Layout.getBaseClassOffset(L) < Layout.getBaseClassOffset(R);
3564  });
3565 
3566  // Dump (non-virtual) bases
3567  for (const CXXRecordDecl *Base : Bases) {
3568  CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base);
3569  DumpRecordLayout(OS, Base, C, BaseOffset, IndentLevel,
3570  Base == PrimaryBase ? "(primary base)" : "(base)",
3571  /*PrintSizeInfo=*/false,
3572  /*IncludeVirtualBases=*/false);
3573  }
3574 
3575  // vbptr (for Microsoft C++ ABI)
3576  if (HasOwnVBPtr) {
3577  PrintOffset(OS, Offset + Layout.getVBPtrOffset(), IndentLevel);
3578  OS << '(' << *RD << " vbtable pointer)\n";
3579  }
3580  }
3581 
3582  // Dump fields.
3583  uint64_t FieldNo = 0;
3584  for (RecordDecl::field_iterator I = RD->field_begin(),
3585  E = RD->field_end(); I != E; ++I, ++FieldNo) {
3586  const FieldDecl &Field = **I;
3587  uint64_t LocalFieldOffsetInBits = Layout.getFieldOffset(FieldNo);
3588  CharUnits FieldOffset =
3589  Offset + C.toCharUnitsFromBits(LocalFieldOffsetInBits);
3590 
3591  // Recursively dump fields of record type.
3592  if (auto RT = Field.getType()->getAs<RecordType>()) {
3593  DumpRecordLayout(OS, RT->getDecl(), C, FieldOffset, IndentLevel,
3594  Field.getName().data(),
3595  /*PrintSizeInfo=*/false,
3596  /*IncludeVirtualBases=*/true);
3597  continue;
3598  }
3599 
3600  if (Field.isBitField()) {
3601  uint64_t LocalFieldByteOffsetInBits = C.toBits(FieldOffset - Offset);
3602  unsigned Begin = LocalFieldOffsetInBits - LocalFieldByteOffsetInBits;
3603  unsigned Width = Field.getBitWidthValue(C);
3604  PrintBitFieldOffset(OS, FieldOffset, Begin, Width, IndentLevel);
3605  } else {
3606  PrintOffset(OS, FieldOffset, IndentLevel);
3607  }
3608  const QualType &FieldType = C.getLangOpts().DumpRecordLayoutsCanonical
3609  ? Field.getType().getCanonicalType()
3610  : Field.getType();
3611  OS << FieldType.getAsString() << ' ' << Field << '\n';
3612  }
3613 
3614  // Dump virtual bases.
3615  if (CXXRD && IncludeVirtualBases) {
3616  const ASTRecordLayout::VBaseOffsetsMapTy &VtorDisps =
3617  Layout.getVBaseOffsetsMap();
3618 
3619  for (const CXXBaseSpecifier &Base : CXXRD->vbases()) {
3620  assert(Base.isVirtual() && "Found non-virtual class!");
3621  const CXXRecordDecl *VBase = Base.getType()->getAsCXXRecordDecl();
3622 
3623  CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBase);
3624 
3625  if (VtorDisps.find(VBase)->second.hasVtorDisp()) {
3626  PrintOffset(OS, VBaseOffset - CharUnits::fromQuantity(4), IndentLevel);
3627  OS << "(vtordisp for vbase " << *VBase << ")\n";
3628  }
3629 
3630  DumpRecordLayout(OS, VBase, C, VBaseOffset, IndentLevel,
3631  VBase == Layout.getPrimaryBase() ?
3632  "(primary virtual base)" : "(virtual base)",
3633  /*PrintSizeInfo=*/false,
3634  /*IncludeVirtualBases=*/false);
3635  }
3636  }
3637 
3638  if (!PrintSizeInfo) return;
3639 
3640  PrintIndentNoOffset(OS, IndentLevel - 1);
3641  OS << "[sizeof=" << Layout.getSize().getQuantity();
3642  if (CXXRD && !isMsLayout(C))
3643  OS << ", dsize=" << Layout.getDataSize().getQuantity();
3644  OS << ", align=" << Layout.getAlignment().getQuantity();
3645  if (C.getTargetInfo().defaultsToAIXPowerAlignment())
3646  OS << ", preferredalign=" << Layout.getPreferredAlignment().getQuantity();
3647 
3648  if (CXXRD) {
3649  OS << ",\n";
3650  PrintIndentNoOffset(OS, IndentLevel - 1);
3651  OS << " nvsize=" << Layout.getNonVirtualSize().getQuantity();
3652  OS << ", nvalign=" << Layout.getNonVirtualAlignment().getQuantity();
3653  if (C.getTargetInfo().defaultsToAIXPowerAlignment())
3654  OS << ", preferrednvalign="
3655  << Layout.getPreferredNVAlignment().getQuantity();
3656  }
3657  OS << "]\n";
3658 }
3659 
3660 void ASTContext::DumpRecordLayout(const RecordDecl *RD, raw_ostream &OS,
3661  bool Simple) const {
3662  if (!Simple) {
3663  ::DumpRecordLayout(OS, RD, *this, CharUnits(), 0, nullptr,
3664  /*PrintSizeInfo*/ true,
3665  /*IncludeVirtualBases=*/true);
3666  return;
3667  }
3668 
3669  // The "simple" format is designed to be parsed by the
3670  // layout-override testing code. There shouldn't be any external
3671  // uses of this format --- when LLDB overrides a layout, it sets up
3672  // the data structures directly --- so feel free to adjust this as
3673  // you like as long as you also update the rudimentary parser for it
3674  // in libFrontend.
3675 
3676  const ASTRecordLayout &Info = getASTRecordLayout(RD);
3677  OS << "Type: " << getTypeDeclType(RD).getAsString() << "\n";
3678  OS << "\nLayout: ";
3679  OS << "<ASTRecordLayout\n";
3680  OS << " Size:" << toBits(Info.getSize()) << "\n";
3681  if (!isMsLayout(*this))
3682  OS << " DataSize:" << toBits(Info.getDataSize()) << "\n";
3683  OS << " Alignment:" << toBits(Info.getAlignment()) << "\n";
3684  if (Target->defaultsToAIXPowerAlignment())
3685  OS << " PreferredAlignment:" << toBits(Info.getPreferredAlignment())
3686  << "\n";
3687  OS << " FieldOffsets: [";
3688  for (unsigned i = 0, e = Info.getFieldCount(); i != e; ++i) {
3689  if (i)
3690  OS << ", ";
3691  OS << Info.getFieldOffset(i);
3692  }
3693  OS << "]>\n";
3694 }
clang::BuiltinType
This class is used for builtin types like 'int'.
Definition: Type.h:2493
RequiresVtordisp
static bool RequiresVtordisp(const llvm::SmallPtrSetImpl< const CXXRecordDecl * > &BasesWithOverriddenMethods, const CXXRecordDecl *RD)
Definition: RecordLayoutBuilder.cpp:3161
clang::ObjCInterfaceDecl
Represents an ObjC class declaration.
Definition: DeclObjC.h:1151
clang::RecordDecl::hasFlexibleArrayMember
bool hasFlexibleArrayMember() const
Definition: Decl.h:3917
clang::ASTContext::getTypeSizeInChars
CharUnits getTypeSizeInChars(QualType T) const
Return the size of the specified (complete) type T, in characters.
Definition: ASTContext.cpp:2450
clang::FieldDecl::getBitWidthValue
unsigned getBitWidthValue(const ASTContext &Ctx) const
Definition: Decl.cpp:4196
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:2963
clang::ASTRecordLayout::getPreferredAlignment
CharUnits getPreferredAlignment() const
getPreferredFieldAlignment - Get the record preferred alignment in characters.
Definition: RecordLayout.h:186
PrintIndentNoOffset
static void PrintIndentNoOffset(raw_ostream &OS, unsigned IndentLevel)
Definition: RecordLayoutBuilder.cpp:3510
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:4616
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:1886
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:1538
computeKeyFunction
static const CXXMethodDecl * computeKeyFunction(ASTContext &Context, const CXXRecordDecl *RD)
Definition: RecordLayoutBuilder.cpp:2282
clang::DiagnosticBuilder
A little helper class used to produce diagnostics.
Definition: Diagnostic.h:1264
clang::DeclContext::specific_decl_iterator
specific_decl_iterator - Iterates over a subrange of declarations stored in a DeclContext,...
Definition: DeclBase.h:2135
clang::ASTContext::getCharWidth
uint64_t getCharWidth() const
Return the size of the character type, in bits.
Definition: ASTContext.h:2249
clang::ASTContext::UnsignedShortTy
CanQualType UnsignedShortTy
Definition: ASTContext.h:1085
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:2430
roundUpSizeToCharAlignment
static uint64_t roundUpSizeToCharAlignment(uint64_t Size, const ASTContext &Context)
Definition: RecordLayoutBuilder.cpp:1459
clang::RecordDecl::mayInsertExtraPadding
bool mayInsertExtraPadding(bool EmitRemark=false) const
Whether we are allowed to insert extra padding between fields.
Definition: Decl.cpp:4670
clang::ASTContext::CountNonClassIvars
unsigned CountNonClassIvars(const ObjCInterfaceDecl *OI) const
Definition: ASTContext.cpp:2826
clang::ObjCIvarDecl::getNextIvar
ObjCIvarDecl * getNextIvar()
Definition: DeclObjC.h:1957
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:2371
clang::Decl::hasAttr
bool hasAttr() const
Definition: DeclBase.h:547
clang::ObjCImplementationDecl
ObjCImplementationDecl - Represents a class definition - this is where method definitions are specifi...
Definition: DeclObjC.h:2546
clang::ConstantArrayType
Represents the canonical version of C arrays with a specified constant size.
Definition: Type.h:2929
clang::ObjCIvarDecl::getCanonicalDecl
ObjCIvarDecl * getCanonicalDecl() override
Retrieves the canonical declaration of this field.
Definition: DeclObjC.h:1961
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:78
clang::NamedDecl::isExternallyVisible
bool isExternallyVisible() const
Definition: Decl.h:407
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:88
isMsLayout
static bool isMsLayout(const ASTContext &Context)
Definition: RecordLayoutBuilder.cpp:2410
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:5310
clang::NamedDecl
This represents a decl that may have a name.
Definition: Decl.h:249
clang::RecordDecl::field_iterator
specific_decl_iterator< FieldDecl > field_iterator
Definition: Decl.h:4080
TargetInfo.h
PrintBitFieldOffset
static void PrintBitFieldOffset(raw_ostream &OS, CharUnits Offset, unsigned Begin, unsigned Width, unsigned IndentLevel)
Definition: RecordLayoutBuilder.cpp:3492
CXXInheritance.h
clang::TargetInfo::useLeadingZeroLengthBitfield
bool useLeadingZeroLengthBitfield() const
Check whether zero length bitfield alignment is respected if they are leading members.
Definition: TargetInfo.h:808
clang::CXXRecordDecl::getDefinition
CXXRecordDecl * getDefinition() const
Definition: DeclCXX.h:535
clang::QualType
A (possibly-)qualified type.
Definition: Type.h:673
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:2835
clang::ASTContext::getBaseElementType
QualType getBaseElementType(const ArrayType *VAT) const
Return the innermost element type of an array type.
Definition: ASTContext.cpp:6297
clang::TargetInfo::getCXXABI
TargetCXXABI getCXXABI() const
Get the C++ ABI currently in use.
Definition: TargetInfo.h:1203
getCharWidth
static unsigned getCharWidth(tok::TokenKind kind, const TargetInfo &Target)
Definition: LiteralSupport.cpp:39
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:183
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:796
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:439
clang::RecordDecl::getDefinition
RecordDecl * getDefinition() const
Returns the RecordDecl that actually defines this struct/union/class.
Definition: Decl.h:4068
llvm::SmallPtrSet
Definition: ASTContext.h:82
clang::QualType::getAsString
static std::string getAsString(SplitQualType split, const PrintingPolicy &Policy)
Definition: Type.h:1015
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:761
clang::AlignRequirementKind
AlignRequirementKind
Definition: ASTContext.h:168
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:543
clang::FunctionDecl::isInlineSpecified
bool isInlineSpecified() const
Determine whether the "inline" keyword was specified for this function.
Definition: Decl.h:2591
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:3338
clang::MSVtorDispMode::ForVFTable
@ ForVFTable
clang::TTK_Interface
@ TTK_Interface
The "__interface" keyword.
Definition: Type.h:5313
clang::ASTContext::toBits
int64_t toBits(CharUnits CharSize) const
Convert a size in characters to a size in bits.
Definition: ASTContext.cpp:2444
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:1490
getPaddingDiagFromTagKind
static unsigned getPaddingDiagFromTagKind(TagTypeKind Tag)
Get diagnostic select index for tag kind for field padding diagnostic message.
Definition: RecordLayoutBuilder.cpp:2231
Decl.h
DeclObjC.h
Offset
unsigned Offset
Definition: Format.cpp:2335
clang::ObjCInterfaceDecl::isThisDeclarationADefinition
bool isThisDeclarationADefinition() const
Determine whether this particular declaration of this class is actually also a definition.
Definition: DeclObjC.h:1509
clang::ASTContext::getTypeAlignInChars
CharUnits getTypeAlignInChars(QualType T) const
Return the ABI-specified alignment of a (complete) type T, in characters.
Definition: ASTContext.cpp:2459
clang::TypeInfo
Definition: ASTContext.h:182
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:3361
clang::TSK_ExplicitInstantiationDeclaration
@ TSK_ExplicitInstantiationDeclaration
This template specialization was instantiated from a template due to an explicit instantiation declar...
Definition: Specifiers.h:187
getFieldOffset
static uint64_t getFieldOffset(const ASTContext &C, const FieldDecl *FD)
Definition: RecordLayoutBuilder.cpp:3384
clang::ASTContext::getExternalSource
ExternalASTSource * getExternalSource() const
Retrieve a pointer to the external AST source associated with this AST context, if any.
Definition: ASTContext.h:1158
clang::TargetInfo::useZeroLengthBitfieldAlignment
bool useZeroLengthBitfieldAlignment() const
Check whether zero length bitfields should force alignment of the next member.
Definition: TargetInfo.h:802
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:4613
clang::CXXMethodDecl::overridden_methods
overridden_method_range overridden_methods() const
Definition: DeclCXX.cpp:2426
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:2629
clang::CXXRecordDecl::methods
method_range methods() const
Definition: DeclCXX.h:631
clang::TagTypeKind
TagTypeKind
The kind of a tag type.
Definition: Type.h:5308
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:231
clang::ASTContext
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:212
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:1174
clang::TargetInfo::getPointerAlign
uint64_t getPointerAlign(unsigned AddrSpace) const
Definition: TargetInfo.h:420
clang::ASTContext::getConstantArrayElementCount
uint64_t getConstantArrayElementCount(const ConstantArrayType *CA) const
Return number of constant array elements.
Definition: ASTContext.cpp:6317
clang::Type::getAs
const T * getAs() const
Member-template getAs<specific type>'.
Definition: Type.h:7161
clang::Decl::isInvalidDecl
bool isInvalidDecl() const
Definition: DeclBase.h:558
clang::TypeInfo::isAlignRequired
bool isAlignRequired()
Definition: ASTContext.h:191
clang::ObjCIvarDecl::getContainingInterface
const ObjCInterfaceDecl * getContainingInterface() const
Return the class interface that this ivar is logically contained in; this is either the interface whe...
Definition: DeclObjC.cpp:1829
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:2245
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:1126
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:814
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:191
clang::TTK_Class
@ TTK_Class
The "class" keyword.
Definition: Type.h:5319
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:1760
clang::TagDecl::isUnion
bool isUnion() const
Definition: Decl.h:3516
clang::CXXRecordDecl::bases
base_class_range bases()
Definition: DeclCXX.h:589
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:11169
Base
clang::ASTContext::DumpRecordLayout
void DumpRecordLayout(const RecordDecl *RD, raw_ostream &OS, bool Simple=false) const
Definition: RecordLayoutBuilder.cpp:3660
clang::TagDecl::isCompleteDefinition
bool isCompleteDefinition() const
Return true if this decl has its body fully specified.
Definition: Decl.h:3433
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:606
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:1086
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:3515
clang::MSVtorDispMode::Never
@ Never
clang::ASTContext::getTargetAddressSpace
unsigned getTargetAddressSpace(QualType T) const
Definition: ASTContext.h:2720
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:1141
clang::ASTContext::UnsignedCharTy
CanQualType UnsignedCharTy
Definition: ASTContext.h:1085
clang::TargetInfo::defaultsToAIXPowerAlignment
virtual bool defaultsToAIXPowerAlignment() const
Whether target defaults to the power alignment rules of AIX.
Definition: TargetInfo.h:1505
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:4239
clang::TargetInfo::getTriple
const llvm::Triple & getTriple() const
Returns the target triple of the primary target.
Definition: TargetInfo.h:1130
clang::ASTContext::UnsignedLongTy
CanQualType UnsignedLongTy
Definition: ASTContext.h:1085
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:255
clang::TemplateSpecializationKind
TemplateSpecializationKind
Describes the kind of template specialization that a particular template specialization declaration r...
Definition: Specifiers.h:173
clang::MSVtorDispMode::ForVBaseOverride
@ ForVBaseOverride
clang::ASTContext::UnsignedIntTy
CanQualType UnsignedIntTy
Definition: ASTContext.h:1085
clang::FieldDecl::isBitField
bool isBitField() const
Determines whether this field is a bitfield.
Definition: Decl.h:2913
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:17
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:604
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:270
clang::ValueDecl
Represent the declaration of a variable (in which case it is an lvalue) a function (in which case it ...
Definition: Decl.h:676
clang::ComplexType
Complex values, per C99 6.2.5p11.
Definition: Type.h:2587
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:3389
clang::ASTRecordLayout::VBaseOffsetsMapTy
llvm::DenseMap< const CXXRecordDecl *, VBaseInfo > VBaseOffsetsMapTy
Definition: RecordLayout.h:59
clang::Type::isIncompleteArrayType
bool isIncompleteArrayType() const
Definition: Type.h:6746
clang::RecordDecl::fields
field_range fields() const
Definition: Decl.h:4083
Begin
SourceLocation Begin
Definition: USRLocFinder.cpp:165
clang::Decl
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:89
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:188
clang::ObjCInterfaceDecl::getSuperClass
ObjCInterfaceDecl * getSuperClass() const
Definition: DeclObjC.cpp:339
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:814
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:1172
clang::ASTContext::getTargetInfo
const TargetInfo & getTargetInfo() const
Definition: ASTContext.h:747
clang::RecordDecl::field_end
field_iterator field_end() const
Definition: Decl.h:4086
PrintOffset
static void PrintOffset(raw_ostream &OS, CharUnits Offset, unsigned IndentLevel)
Definition: RecordLayoutBuilder.cpp:3486
clang::TargetInfo::useExplicitBitFieldAlignment
bool useExplicitBitFieldAlignment() const
Check whether explicit bitfield alignment attributes should be.
Definition: TargetInfo.h:824
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:7111
clang::Builtin::ID
ID
Definition: Builtins.h:48
clang::SourceLocation::isInvalid
bool isInvalid() const
Definition: SourceLocation.h:113
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:3027
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:1817
clang
Definition: CalledOnceCheck.h:17
clang::LangOptions::MSVC2015
@ MSVC2015
Definition: LangOptions.h:122
clang::IndirectFieldDecl
Represents a field injected from an anonymous union/struct into the parent scope.
Definition: Decl.h:3089
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:1645
clang::TypeInfo::Align
unsigned Align
Definition: ASTContext.h:184
clang::ASTContext::toCharUnitsFromBits
CharUnits toCharUnitsFromBits(int64_t BitSize) const
Convert a size in bits to a size in characters.
Definition: ASTContext.cpp:2439
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:417
clang::ObjCIvarDecl
ObjCIvarDecl - Represents an ObjC instance variable.
Definition: DeclObjC.h:1924
clang::CXXBaseSpecifier
Represents a base class of a C++ class.
Definition: DeclCXX.h:147
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:4640
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:3507
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:440
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:1631
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:3404
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:3246
clang::ObjCContainerDecl
ObjCContainerDecl - Represents a container for method declarations.
Definition: DeclObjC.h:948
clang::CXXRecordDecl::isTrivial
bool isTrivial() const
Determine whether this class is considered trivial.
Definition: DeclCXX.h:1378
clang::CXXRecordDecl::isDynamicClass
bool isDynamicClass() const
Definition: DeclCXX.h:555
clang::RecordType::getDecl
RecordDecl * getDecl() const
Definition: Type.h:4623
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:1159
clang::ReferenceType
Base for LValueReferenceType and RValueReferenceType.
Definition: Type.h:2751
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:1874
recordUsesEBO
static bool recordUsesEBO(const RecordDecl *RD)
Definition: RecordLayoutBuilder.cpp:2857
clang::CXXRecordDecl::hasUserDeclaredDestructor
bool hasUserDeclaredDestructor() const
Determine whether this class has a user-declared destructor.
Definition: DeclCXX.h:975
clang::ValueDecl::getType
QualType getType() const
Definition: Decl.h:687
clang::CXXRecordDecl::getIndirectPrimaryBases
void getIndirectPrimaryBases(CXXIndirectPrimaryBaseSet &Bases) const
Get the indirect primary bases for this class.
Definition: CXXInheritance.cpp:703
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:2958
clang::IndirectFieldDecl::chain
ArrayRef< NamedDecl * > chain() const
Definition: Decl.h:3111
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:1919
isAIXLayout
static bool isAIXLayout(const ASTContext &Context)
Definition: RecordLayoutBuilder.cpp:1531
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:179
clang::Decl::getLocation
SourceLocation getLocation() const
Definition: DeclBase.h:430
clang::Decl::getMaxAlignment
unsigned getMaxAlignment() const
getMaxAlignment - return the maximum alignment specified by attributes on this decl,...
Definition: DeclBase.cpp:428
clang::FunctionDecl
Represents a function declaration or definition.
Definition: Decl.h:1856
clang::RecordDecl
Represents a struct/union/class.
Definition: Decl.h:3863
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:765
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:1499
RecordLayout.h
clang::declaresSameEntity
bool declaresSameEntity(const Decl *D1, const Decl *D2)
Determine whether two declarations declare the same entity.
Definition: DeclBase.h:1198
clang::DiagnosticsEngine::Report
DiagnosticBuilder Report(SourceLocation Loc, unsigned DiagID)
Issue the message to the client.
Definition: Diagnostic.h:1523
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:1528
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:2063
clang::CXXMethodDecl
Represents a static or instance method of a struct/union/class.
Definition: DeclCXX.h:1948