Bug Summary

File:tools/clang/lib/AST/RecordLayoutBuilder.cpp
Warning:line 1142, column 10
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name RecordLayoutBuilder.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -mrelocation-model pic -pic-level 2 -mthread-model posix -relaxed-aliasing -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-8/lib/clang/8.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/tools/clang/lib/AST -I /build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST -I /build/llvm-toolchain-snapshot-8~svn345461/tools/clang/include -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/include -I /build/llvm-toolchain-snapshot-8~svn345461/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/include/clang/8.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-8/lib/clang/8.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/tools/clang/lib/AST -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -fobjc-runtime=gcc -fno-common -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-10-27-211344-32123-1 -x c++ /build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp -faddrsig
1//=== RecordLayoutBuilder.cpp - Helper class for building record layouts ---==//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "clang/AST/RecordLayout.h"
11#include "clang/AST/ASTContext.h"
12#include "clang/AST/Attr.h"
13#include "clang/AST/CXXInheritance.h"
14#include "clang/AST/Decl.h"
15#include "clang/AST/DeclCXX.h"
16#include "clang/AST/DeclObjC.h"
17#include "clang/AST/Expr.h"
18#include "clang/Basic/TargetInfo.h"
19#include "clang/Sema/SemaDiagnostic.h"
20#include "llvm/ADT/SmallSet.h"
21#include "llvm/Support/Format.h"
22#include "llvm/Support/MathExtras.h"
23
24using namespace clang;
25
26namespace {
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.
39struct BaseSubobjectInfo {
40 /// Class - The class for this base info.
41 const CXXRecordDecl *Class;
42
43 /// IsVirtual - Whether the BaseInfo represents a virtual base or not.
44 bool IsVirtual;
45
46 /// Bases - Information about the base subobjects.
47 SmallVector<BaseSubobjectInfo*, 4> Bases;
48
49 /// PrimaryVirtualBaseInfo - Holds the base info for the primary virtual base
50 /// of this base info (if one exists).
51 BaseSubobjectInfo *PrimaryVirtualBaseInfo;
52
53 // FIXME: Document.
54 const BaseSubobjectInfo *Derived;
55};
56
57/// Externally provided layout. Typically used when the AST source, such
58/// as DWARF, lacks all the information that was available at compile time, such
59/// as alignment attributes on fields and pragmas in effect.
60struct 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) &&((FieldOffsets.count(FD) && "Field does not have an external offset"
) ? static_cast<void> (0) : __assert_fail ("FieldOffsets.count(FD) && \"Field does not have an external offset\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 82, __PRETTY_FUNCTION__))
82 "Field does not have an external offset")((FieldOffsets.count(FD) && "Field does not have an external offset"
) ? static_cast<void> (0) : __assert_fail ("FieldOffsets.count(FD) && \"Field does not have an external offset\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 82, __PRETTY_FUNCTION__))
;
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.
105class 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,
132 CharUnits Offset);
133 void UpdateEmptyFieldSubobjects(const FieldDecl *FD, CharUnits Offset);
134
135 /// AnyEmptySubobjectsBeyondOffset - Returns whether there are any empty
136 /// subobjects beyond the given offset.
137 bool AnyEmptySubobjectsBeyondOffset(CharUnits Offset) const {
138 return Offset <= MaxEmptyClassOffset;
139 }
140
141 CharUnits
142 getFieldOffset(const ASTRecordLayout &Layout, unsigned FieldNo) const {
143 uint64_t FieldOffset = Layout.getFieldOffset(FieldNo);
144 assert(FieldOffset % CharWidth == 0 &&((FieldOffset % CharWidth == 0 && "Field offset not at char boundary!"
) ? static_cast<void> (0) : __assert_fail ("FieldOffset % CharWidth == 0 && \"Field offset not at char boundary!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 145, __PRETTY_FUNCTION__))
145 "Field offset not at char boundary!")((FieldOffset % CharWidth == 0 && "Field offset not at char boundary!"
) ? static_cast<void> (0) : __assert_fail ("FieldOffset % CharWidth == 0 && \"Field offset not at char boundary!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 145, __PRETTY_FUNCTION__))
;
146
147 return Context.toCharUnitsFromBits(FieldOffset);
148 }
149
150protected:
151 bool CanPlaceSubobjectAtOffset(const CXXRecordDecl *RD,
152 CharUnits Offset) const;
153
154 bool CanPlaceBaseSubobjectAtOffset(const BaseSubobjectInfo *Info,
155 CharUnits Offset);
156
157 bool CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD,
158 const CXXRecordDecl *Class,
159 CharUnits Offset) const;
160 bool CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD,
161 CharUnits Offset) const;
162
163public:
164 /// This holds the size of the largest empty subobject (either a base
165 /// or a member). Will be zero if the record being built doesn't contain
166 /// any empty classes.
167 CharUnits SizeOfLargestEmptySubobject;
168
169 EmptySubobjectMap(const ASTContext &Context, const CXXRecordDecl *Class)
170 : Context(Context), CharWidth(Context.getCharWidth()), Class(Class) {
171 ComputeEmptySubobjectSizes();
172 }
173
174 /// CanPlaceBaseAtOffset - Return whether the given base class can be placed
175 /// at the given offset.
176 /// Returns false if placing the record will result in two components
177 /// (direct or indirect) of the same type having the same offset.
178 bool CanPlaceBaseAtOffset(const BaseSubobjectInfo *Info,
179 CharUnits Offset);
180
181 /// CanPlaceFieldAtOffset - Return whether a field can be placed at the given
182 /// offset.
183 bool CanPlaceFieldAtOffset(const FieldDecl *FD, CharUnits Offset);
184};
185
186void EmptySubobjectMap::ComputeEmptySubobjectSizes() {
187 // Check the bases.
188 for (const CXXBaseSpecifier &Base : Class->bases()) {
189 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
190
191 CharUnits EmptySize;
192 const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
193 if (BaseDecl->isEmpty()) {
194 // If the class decl is empty, get its size.
195 EmptySize = Layout.getSize();
196 } else {
197 // Otherwise, we get the largest empty subobject for the decl.
198 EmptySize = Layout.getSizeOfLargestEmptySubobject();
199 }
200
201 if (EmptySize > SizeOfLargestEmptySubobject)
202 SizeOfLargestEmptySubobject = EmptySize;
203 }
204
205 // Check the fields.
206 for (const FieldDecl *FD : Class->fields()) {
207 const RecordType *RT =
208 Context.getBaseElementType(FD->getType())->getAs<RecordType>();
209
210 // We only care about record types.
211 if (!RT)
212 continue;
213
214 CharUnits EmptySize;
215 const CXXRecordDecl *MemberDecl = RT->getAsCXXRecordDecl();
216 const ASTRecordLayout &Layout = Context.getASTRecordLayout(MemberDecl);
217 if (MemberDecl->isEmpty()) {
218 // If the class decl is empty, get its size.
219 EmptySize = Layout.getSize();
220 } else {
221 // Otherwise, we get the largest empty subobject for the decl.
222 EmptySize = Layout.getSizeOfLargestEmptySubobject();
223 }
224
225 if (EmptySize > SizeOfLargestEmptySubobject)
226 SizeOfLargestEmptySubobject = EmptySize;
227 }
228}
229
230bool
231EmptySubobjectMap::CanPlaceSubobjectAtOffset(const CXXRecordDecl *RD,
232 CharUnits Offset) const {
233 // We only need to check empty bases.
234 if (!RD->isEmpty())
235 return true;
236
237 EmptyClassOffsetsMapTy::const_iterator I = EmptyClassOffsets.find(Offset);
238 if (I == EmptyClassOffsets.end())
239 return true;
240
241 const ClassVectorTy &Classes = I->second;
242 if (std::find(Classes.begin(), Classes.end(), RD) == Classes.end())
243 return true;
244
245 // There is already an empty class of the same type at this offset.
246 return false;
247}
248
249void EmptySubobjectMap::AddSubobjectAtOffset(const CXXRecordDecl *RD,
250 CharUnits Offset) {
251 // We only care about empty bases.
252 if (!RD->isEmpty())
253 return;
254
255 // If we have empty structures inside a union, we can assign both
256 // the same offset. Just avoid pushing them twice in the list.
257 ClassVectorTy &Classes = EmptyClassOffsets[Offset];
258 if (std::find(Classes.begin(), Classes.end(), RD) != Classes.end())
259 return;
260
261 Classes.push_back(RD);
262
263 // Update the empty class offset.
264 if (Offset > MaxEmptyClassOffset)
265 MaxEmptyClassOffset = Offset;
266}
267
268bool
269EmptySubobjectMap::CanPlaceBaseSubobjectAtOffset(const BaseSubobjectInfo *Info,
270 CharUnits Offset) {
271 // We don't have to keep looking past the maximum offset that's known to
272 // contain an empty class.
273 if (!AnyEmptySubobjectsBeyondOffset(Offset))
274 return true;
275
276 if (!CanPlaceSubobjectAtOffset(Info->Class, Offset))
277 return false;
278
279 // Traverse all non-virtual bases.
280 const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
281 for (const BaseSubobjectInfo *Base : Info->Bases) {
282 if (Base->IsVirtual)
283 continue;
284
285 CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
286
287 if (!CanPlaceBaseSubobjectAtOffset(Base, BaseOffset))
288 return false;
289 }
290
291 if (Info->PrimaryVirtualBaseInfo) {
292 BaseSubobjectInfo *PrimaryVirtualBaseInfo = Info->PrimaryVirtualBaseInfo;
293
294 if (Info == PrimaryVirtualBaseInfo->Derived) {
295 if (!CanPlaceBaseSubobjectAtOffset(PrimaryVirtualBaseInfo, Offset))
296 return false;
297 }
298 }
299
300 // Traverse all member variables.
301 unsigned FieldNo = 0;
302 for (CXXRecordDecl::field_iterator I = Info->Class->field_begin(),
303 E = Info->Class->field_end(); I != E; ++I, ++FieldNo) {
304 if (I->isBitField())
305 continue;
306
307 CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
308 if (!CanPlaceFieldSubobjectAtOffset(*I, FieldOffset))
309 return false;
310 }
311
312 return true;
313}
314
315void EmptySubobjectMap::UpdateEmptyBaseSubobjects(const BaseSubobjectInfo *Info,
316 CharUnits Offset,
317 bool PlacingEmptyBase) {
318 if (!PlacingEmptyBase && Offset >= SizeOfLargestEmptySubobject) {
319 // We know that the only empty subobjects that can conflict with empty
320 // subobject of non-empty bases, are empty bases that can be placed at
321 // offset zero. Because of this, we only need to keep track of empty base
322 // subobjects with offsets less than the size of the largest empty
323 // subobject for our class.
324 return;
325 }
326
327 AddSubobjectAtOffset(Info->Class, Offset);
328
329 // Traverse all non-virtual bases.
330 const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
331 for (const BaseSubobjectInfo *Base : Info->Bases) {
332 if (Base->IsVirtual)
333 continue;
334
335 CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
336 UpdateEmptyBaseSubobjects(Base, BaseOffset, PlacingEmptyBase);
337 }
338
339 if (Info->PrimaryVirtualBaseInfo) {
340 BaseSubobjectInfo *PrimaryVirtualBaseInfo = Info->PrimaryVirtualBaseInfo;
341
342 if (Info == PrimaryVirtualBaseInfo->Derived)
343 UpdateEmptyBaseSubobjects(PrimaryVirtualBaseInfo, Offset,
344 PlacingEmptyBase);
345 }
346
347 // Traverse all member variables.
348 unsigned FieldNo = 0;
349 for (CXXRecordDecl::field_iterator I = Info->Class->field_begin(),
350 E = Info->Class->field_end(); I != E; ++I, ++FieldNo) {
351 if (I->isBitField())
352 continue;
353
354 CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
355 UpdateEmptyFieldSubobjects(*I, FieldOffset);
356 }
357}
358
359bool EmptySubobjectMap::CanPlaceBaseAtOffset(const BaseSubobjectInfo *Info,
360 CharUnits Offset) {
361 // If we know this class doesn't have any empty subobjects we don't need to
362 // bother checking.
363 if (SizeOfLargestEmptySubobject.isZero())
364 return true;
365
366 if (!CanPlaceBaseSubobjectAtOffset(Info, Offset))
367 return false;
368
369 // We are able to place the base at this offset. Make sure to update the
370 // empty base subobject map.
371 UpdateEmptyBaseSubobjects(Info, Offset, Info->Class->isEmpty());
372 return true;
373}
374
375bool
376EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD,
377 const CXXRecordDecl *Class,
378 CharUnits Offset) const {
379 // We don't have to keep looking past the maximum offset that's known to
380 // contain an empty class.
381 if (!AnyEmptySubobjectsBeyondOffset(Offset))
382 return true;
383
384 if (!CanPlaceSubobjectAtOffset(RD, Offset))
385 return false;
386
387 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
388
389 // Traverse all non-virtual bases.
390 for (const CXXBaseSpecifier &Base : RD->bases()) {
391 if (Base.isVirtual())
392 continue;
393
394 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
395
396 CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(BaseDecl);
397 if (!CanPlaceFieldSubobjectAtOffset(BaseDecl, Class, BaseOffset))
398 return false;
399 }
400
401 if (RD == Class) {
402 // This is the most derived class, traverse virtual bases as well.
403 for (const CXXBaseSpecifier &Base : RD->vbases()) {
404 const CXXRecordDecl *VBaseDecl = Base.getType()->getAsCXXRecordDecl();
405
406 CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBaseDecl);
407 if (!CanPlaceFieldSubobjectAtOffset(VBaseDecl, Class, VBaseOffset))
408 return false;
409 }
410 }
411
412 // Traverse all member variables.
413 unsigned FieldNo = 0;
414 for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
415 I != E; ++I, ++FieldNo) {
416 if (I->isBitField())
417 continue;
418
419 CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
420
421 if (!CanPlaceFieldSubobjectAtOffset(*I, FieldOffset))
422 return false;
423 }
424
425 return true;
426}
427
428bool
429EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD,
430 CharUnits Offset) const {
431 // We don't have to keep looking past the maximum offset that's known to
432 // contain an empty class.
433 if (!AnyEmptySubobjectsBeyondOffset(Offset))
434 return true;
435
436 QualType T = FD->getType();
437 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
438 return CanPlaceFieldSubobjectAtOffset(RD, RD, Offset);
439
440 // If we have an array type we need to look at every element.
441 if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
442 QualType ElemTy = Context.getBaseElementType(AT);
443 const RecordType *RT = ElemTy->getAs<RecordType>();
444 if (!RT)
445 return true;
446
447 const CXXRecordDecl *RD = RT->getAsCXXRecordDecl();
448 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
449
450 uint64_t NumElements = Context.getConstantArrayElementCount(AT);
451 CharUnits ElementOffset = Offset;
452 for (uint64_t I = 0; I != NumElements; ++I) {
453 // We don't have to keep looking past the maximum offset that's known to
454 // contain an empty class.
455 if (!AnyEmptySubobjectsBeyondOffset(ElementOffset))
456 return true;
457
458 if (!CanPlaceFieldSubobjectAtOffset(RD, RD, ElementOffset))
459 return false;
460
461 ElementOffset += Layout.getSize();
462 }
463 }
464
465 return true;
466}
467
468bool
469EmptySubobjectMap::CanPlaceFieldAtOffset(const FieldDecl *FD,
470 CharUnits Offset) {
471 if (!CanPlaceFieldSubobjectAtOffset(FD, Offset))
472 return false;
473
474 // We are able to place the member variable at this offset.
475 // Make sure to update the empty base subobject map.
476 UpdateEmptyFieldSubobjects(FD, Offset);
477 return true;
478}
479
480void EmptySubobjectMap::UpdateEmptyFieldSubobjects(const CXXRecordDecl *RD,
481 const CXXRecordDecl *Class,
482 CharUnits Offset) {
483 // We know that the only empty subobjects that can conflict with empty
484 // field subobjects are subobjects of empty bases that can be placed at offset
485 // zero. Because of this, we only need to keep track of empty field
486 // subobjects with offsets less than the size of the largest empty
487 // subobject for our class.
488 if (Offset >= SizeOfLargestEmptySubobject)
489 return;
490
491 AddSubobjectAtOffset(RD, Offset);
492
493 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
494
495 // Traverse all non-virtual bases.
496 for (const CXXBaseSpecifier &Base : RD->bases()) {
497 if (Base.isVirtual())
498 continue;
499
500 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
501
502 CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(BaseDecl);
503 UpdateEmptyFieldSubobjects(BaseDecl, Class, BaseOffset);
504 }
505
506 if (RD == Class) {
507 // This is the most derived class, traverse virtual bases as well.
508 for (const CXXBaseSpecifier &Base : RD->vbases()) {
509 const CXXRecordDecl *VBaseDecl = Base.getType()->getAsCXXRecordDecl();
510
511 CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBaseDecl);
512 UpdateEmptyFieldSubobjects(VBaseDecl, Class, VBaseOffset);
513 }
514 }
515
516 // Traverse all member variables.
517 unsigned FieldNo = 0;
518 for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
519 I != E; ++I, ++FieldNo) {
520 if (I->isBitField())
521 continue;
522
523 CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
524
525 UpdateEmptyFieldSubobjects(*I, FieldOffset);
526 }
527}
528
529void EmptySubobjectMap::UpdateEmptyFieldSubobjects(const FieldDecl *FD,
530 CharUnits Offset) {
531 QualType T = FD->getType();
532 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl()) {
533 UpdateEmptyFieldSubobjects(RD, RD, Offset);
534 return;
535 }
536
537 // If we have an array type we need to update every element.
538 if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
539 QualType ElemTy = Context.getBaseElementType(AT);
540 const RecordType *RT = ElemTy->getAs<RecordType>();
541 if (!RT)
542 return;
543
544 const CXXRecordDecl *RD = RT->getAsCXXRecordDecl();
545 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
546
547 uint64_t NumElements = Context.getConstantArrayElementCount(AT);
548 CharUnits ElementOffset = Offset;
549
550 for (uint64_t I = 0; I != NumElements; ++I) {
551 // We know that the only empty subobjects that can conflict with empty
552 // field subobjects are subobjects of empty bases that can be placed at
553 // offset zero. Because of this, we only need to keep track of empty field
554 // subobjects with offsets less than the size of the largest empty
555 // subobject for our class.
556 if (ElementOffset >= SizeOfLargestEmptySubobject)
557 return;
558
559 UpdateEmptyFieldSubobjects(RD, RD, ElementOffset);
560 ElementOffset += Layout.getSize();
561 }
562 }
563}
564
565typedef llvm::SmallPtrSet<const CXXRecordDecl*, 4> ClassSetTy;
566
567class ItaniumRecordLayoutBuilder {
568protected:
569 // FIXME: Remove this and make the appropriate fields public.
570 friend class clang::ASTContext;
571
572 const ASTContext &Context;
573
574 EmptySubobjectMap *EmptySubobjects;
575
576 /// Size - The current size of the record layout.
577 uint64_t Size;
578
579 /// Alignment - The current alignment of the record layout.
580 CharUnits Alignment;
581
582 /// The alignment if attribute packed is not used.
583 CharUnits UnpackedAlignment;
584
585 /// \brief The maximum of the alignments of top-level members.
586 CharUnits UnadjustedAlignment;
587
588 SmallVector<uint64_t, 16> FieldOffsets;
589
590 /// Whether the external AST source has provided a layout for this
591 /// record.
592 unsigned UseExternalLayout : 1;
593
594 /// Whether we need to infer alignment, even when we have an
595 /// externally-provided layout.
596 unsigned InferAlignment : 1;
597
598 /// Packed - Whether the record is packed or not.
599 unsigned Packed : 1;
600
601 unsigned IsUnion : 1;
602
603 unsigned IsMac68kAlign : 1;
604
605 unsigned IsMsStruct : 1;
606
607 /// UnfilledBitsInLastUnit - If the last field laid out was a bitfield,
608 /// this contains the number of bits in the last unit that can be used for
609 /// an adjacent bitfield if necessary. The unit in question is usually
610 /// a byte, but larger units are used if IsMsStruct.
611 unsigned char UnfilledBitsInLastUnit;
612 /// LastBitfieldTypeSize - If IsMsStruct, represents the size of the type
613 /// of the previous field if it was a bitfield.
614 unsigned char LastBitfieldTypeSize;
615
616 /// MaxFieldAlignment - The maximum allowed field alignment. This is set by
617 /// #pragma pack.
618 CharUnits MaxFieldAlignment;
619
620 /// DataSize - The data size of the record being laid out.
621 uint64_t DataSize;
622
623 CharUnits NonVirtualSize;
624 CharUnits NonVirtualAlignment;
625
626 /// PrimaryBase - the primary base class (if one exists) of the class
627 /// we're laying out.
628 const CXXRecordDecl *PrimaryBase;
629
630 /// PrimaryBaseIsVirtual - Whether the primary base of the class we're laying
631 /// out is virtual.
632 bool PrimaryBaseIsVirtual;
633
634 /// HasOwnVFPtr - Whether the class provides its own vtable/vftbl
635 /// pointer, as opposed to inheriting one from a primary base class.
636 bool HasOwnVFPtr;
637
638 /// the flag of field offset changing due to packed attribute.
639 bool HasPackedField;
640
641 typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
642
643 /// Bases - base classes and their offsets in the record.
644 BaseOffsetsMapTy Bases;
645
646 // VBases - virtual base classes and their offsets in the record.
647 ASTRecordLayout::VBaseOffsetsMapTy VBases;
648
649 /// IndirectPrimaryBases - Virtual base classes, direct or indirect, that are
650 /// primary base classes for some other direct or indirect base class.
651 CXXIndirectPrimaryBaseSet IndirectPrimaryBases;
652
653 /// FirstNearlyEmptyVBase - The first nearly empty virtual base class in
654 /// inheritance graph order. Used for determining the primary base class.
655 const CXXRecordDecl *FirstNearlyEmptyVBase;
656
657 /// VisitedVirtualBases - A set of all the visited virtual bases, used to
658 /// avoid visiting virtual bases more than once.
659 llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBases;
660
661 /// Valid if UseExternalLayout is true.
662 ExternalLayout External;
663
664 ItaniumRecordLayoutBuilder(const ASTContext &Context,
665 EmptySubobjectMap *EmptySubobjects)
666 : Context(Context), EmptySubobjects(EmptySubobjects), Size(0),
667 Alignment(CharUnits::One()), UnpackedAlignment(CharUnits::One()),
668 UnadjustedAlignment(CharUnits::One()),
669 UseExternalLayout(false), InferAlignment(false), Packed(false),
670 IsUnion(false), IsMac68kAlign(false), IsMsStruct(false),
671 UnfilledBitsInLastUnit(0), LastBitfieldTypeSize(0),
672 MaxFieldAlignment(CharUnits::Zero()), DataSize(0),
673 NonVirtualSize(CharUnits::Zero()),
674 NonVirtualAlignment(CharUnits::One()), PrimaryBase(nullptr),
675 PrimaryBaseIsVirtual(false), HasOwnVFPtr(false),
676 HasPackedField(false), FirstNearlyEmptyVBase(nullptr) {}
677
678 void Layout(const RecordDecl *D);
679 void Layout(const CXXRecordDecl *D);
680 void Layout(const ObjCInterfaceDecl *D);
681
682 void LayoutFields(const RecordDecl *D);
683 void LayoutField(const FieldDecl *D, bool InsertExtraPadding);
684 void LayoutWideBitField(uint64_t FieldSize, uint64_t TypeSize,
685 bool FieldPacked, const FieldDecl *D);
686 void LayoutBitField(const FieldDecl *D);
687
688 TargetCXXABI getCXXABI() const {
689 return Context.getTargetInfo().getCXXABI();
690 }
691
692 /// BaseSubobjectInfoAllocator - Allocator for BaseSubobjectInfo objects.
693 llvm::SpecificBumpPtrAllocator<BaseSubobjectInfo> BaseSubobjectInfoAllocator;
694
695 typedef llvm::DenseMap<const CXXRecordDecl *, BaseSubobjectInfo *>
696 BaseSubobjectInfoMapTy;
697
698 /// VirtualBaseInfo - Map from all the (direct or indirect) virtual bases
699 /// of the class we're laying out to their base subobject info.
700 BaseSubobjectInfoMapTy VirtualBaseInfo;
701
702 /// NonVirtualBaseInfo - Map from all the direct non-virtual bases of the
703 /// class we're laying out to their base subobject info.
704 BaseSubobjectInfoMapTy NonVirtualBaseInfo;
705
706 /// ComputeBaseSubobjectInfo - Compute the base subobject information for the
707 /// bases of the given class.
708 void ComputeBaseSubobjectInfo(const CXXRecordDecl *RD);
709
710 /// ComputeBaseSubobjectInfo - Compute the base subobject information for a
711 /// single class and all of its base classes.
712 BaseSubobjectInfo *ComputeBaseSubobjectInfo(const CXXRecordDecl *RD,
713 bool IsVirtual,
714 BaseSubobjectInfo *Derived);
715
716 /// DeterminePrimaryBase - Determine the primary base of the given class.
717 void DeterminePrimaryBase(const CXXRecordDecl *RD);
718
719 void SelectPrimaryVBase(const CXXRecordDecl *RD);
720
721 void EnsureVTablePointerAlignment(CharUnits UnpackedBaseAlign);
722
723 /// LayoutNonVirtualBases - Determines the primary base class (if any) and
724 /// lays it out. Will then proceed to lay out all non-virtual base clasess.
725 void LayoutNonVirtualBases(const CXXRecordDecl *RD);
726
727 /// LayoutNonVirtualBase - Lays out a single non-virtual base.
728 void LayoutNonVirtualBase(const BaseSubobjectInfo *Base);
729
730 void AddPrimaryVirtualBaseOffsets(const BaseSubobjectInfo *Info,
731 CharUnits Offset);
732
733 /// LayoutVirtualBases - Lays out all the virtual bases.
734 void LayoutVirtualBases(const CXXRecordDecl *RD,
735 const CXXRecordDecl *MostDerivedClass);
736
737 /// LayoutVirtualBase - Lays out a single virtual base.
738 void LayoutVirtualBase(const BaseSubobjectInfo *Base);
739
740 /// LayoutBase - Will lay out a base and return the offset where it was
741 /// placed, in chars.
742 CharUnits LayoutBase(const BaseSubobjectInfo *Base);
743
744 /// InitializeLayout - Initialize record layout for the given record decl.
745 void InitializeLayout(const Decl *D);
746
747 /// FinishLayout - Finalize record layout. Adjust record size based on the
748 /// alignment.
749 void FinishLayout(const NamedDecl *D);
750
751 void UpdateAlignment(CharUnits NewAlignment, CharUnits UnpackedNewAlignment);
752 void UpdateAlignment(CharUnits NewAlignment) {
753 UpdateAlignment(NewAlignment, NewAlignment);
754 }
755
756 /// Retrieve the externally-supplied field offset for the given
757 /// field.
758 ///
759 /// \param Field The field whose offset is being queried.
760 /// \param ComputedOffset The offset that we've computed for this field.
761 uint64_t updateExternalFieldOffset(const FieldDecl *Field,
762 uint64_t ComputedOffset);
763
764 void CheckFieldPadding(uint64_t Offset, uint64_t UnpaddedOffset,
765 uint64_t UnpackedOffset, unsigned UnpackedAlign,
766 bool isPacked, const FieldDecl *D);
767
768 DiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID);
769
770 CharUnits getSize() const {
771 assert(Size % Context.getCharWidth() == 0)((Size % Context.getCharWidth() == 0) ? static_cast<void>
(0) : __assert_fail ("Size % Context.getCharWidth() == 0", "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 771, __PRETTY_FUNCTION__))
;
772 return Context.toCharUnitsFromBits(Size);
773 }
774 uint64_t getSizeInBits() const { return Size; }
775
776 void setSize(CharUnits NewSize) { Size = Context.toBits(NewSize); }
777 void setSize(uint64_t NewSize) { Size = NewSize; }
778
779 CharUnits getAligment() const { return Alignment; }
780
781 CharUnits getDataSize() const {
782 assert(DataSize % Context.getCharWidth() == 0)((DataSize % Context.getCharWidth() == 0) ? static_cast<void
> (0) : __assert_fail ("DataSize % Context.getCharWidth() == 0"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 782, __PRETTY_FUNCTION__))
;
783 return Context.toCharUnitsFromBits(DataSize);
784 }
785 uint64_t getDataSizeInBits() const { return DataSize; }
786
787 void setDataSize(CharUnits NewSize) { DataSize = Context.toBits(NewSize); }
788 void setDataSize(uint64_t NewSize) { DataSize = NewSize; }
789
790 ItaniumRecordLayoutBuilder(const ItaniumRecordLayoutBuilder &) = delete;
791 void operator=(const ItaniumRecordLayoutBuilder &) = delete;
792};
793} // end anonymous namespace
794
795void ItaniumRecordLayoutBuilder::SelectPrimaryVBase(const CXXRecordDecl *RD) {
796 for (const auto &I : RD->bases()) {
797 assert(!I.getType()->isDependentType() &&((!I.getType()->isDependentType() && "Cannot layout class with dependent bases."
) ? static_cast<void> (0) : __assert_fail ("!I.getType()->isDependentType() && \"Cannot layout class with dependent bases.\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 798, __PRETTY_FUNCTION__))
798 "Cannot layout class with dependent bases.")((!I.getType()->isDependentType() && "Cannot layout class with dependent bases."
) ? static_cast<void> (0) : __assert_fail ("!I.getType()->isDependentType() && \"Cannot layout class with dependent bases.\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 798, __PRETTY_FUNCTION__))
;
799
800 const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
801
802 // Check if this is a nearly empty virtual base.
803 if (I.isVirtual() && Context.isNearlyEmpty(Base)) {
804 // If it's not an indirect primary base, then we've found our primary
805 // base.
806 if (!IndirectPrimaryBases.count(Base)) {
807 PrimaryBase = Base;
808 PrimaryBaseIsVirtual = true;
809 return;
810 }
811
812 // Is this the first nearly empty virtual base?
813 if (!FirstNearlyEmptyVBase)
814 FirstNearlyEmptyVBase = Base;
815 }
816
817 SelectPrimaryVBase(Base);
818 if (PrimaryBase)
819 return;
820 }
821}
822
823/// DeterminePrimaryBase - Determine the primary base of the given class.
824void ItaniumRecordLayoutBuilder::DeterminePrimaryBase(const CXXRecordDecl *RD) {
825 // If the class isn't dynamic, it won't have a primary base.
826 if (!RD->isDynamicClass())
827 return;
828
829 // Compute all the primary virtual bases for all of our direct and
830 // indirect bases, and record all their primary virtual base classes.
831 RD->getIndirectPrimaryBases(IndirectPrimaryBases);
832
833 // If the record has a dynamic base class, attempt to choose a primary base
834 // class. It is the first (in direct base class order) non-virtual dynamic
835 // base class, if one exists.
836 for (const auto &I : RD->bases()) {
837 // Ignore virtual bases.
838 if (I.isVirtual())
839 continue;
840
841 const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
842
843 if (Base->isDynamicClass()) {
844 // We found it.
845 PrimaryBase = Base;
846 PrimaryBaseIsVirtual = false;
847 return;
848 }
849 }
850
851 // Under the Itanium ABI, if there is no non-virtual primary base class,
852 // try to compute the primary virtual base. The primary virtual base is
853 // the first nearly empty virtual base that is not an indirect primary
854 // virtual base class, if one exists.
855 if (RD->getNumVBases() != 0) {
856 SelectPrimaryVBase(RD);
857 if (PrimaryBase)
858 return;
859 }
860
861 // Otherwise, it is the first indirect primary base class, if one exists.
862 if (FirstNearlyEmptyVBase) {
863 PrimaryBase = FirstNearlyEmptyVBase;
864 PrimaryBaseIsVirtual = true;
865 return;
866 }
867
868 assert(!PrimaryBase && "Should not get here with a primary base!")((!PrimaryBase && "Should not get here with a primary base!"
) ? static_cast<void> (0) : __assert_fail ("!PrimaryBase && \"Should not get here with a primary base!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 868, __PRETTY_FUNCTION__))
;
869}
870
871BaseSubobjectInfo *ItaniumRecordLayoutBuilder::ComputeBaseSubobjectInfo(
872 const CXXRecordDecl *RD, bool IsVirtual, BaseSubobjectInfo *Derived) {
873 BaseSubobjectInfo *Info;
874
875 if (IsVirtual) {
876 // Check if we already have info about this virtual base.
877 BaseSubobjectInfo *&InfoSlot = VirtualBaseInfo[RD];
878 if (InfoSlot) {
879 assert(InfoSlot->Class == RD && "Wrong class for virtual base info!")((InfoSlot->Class == RD && "Wrong class for virtual base info!"
) ? static_cast<void> (0) : __assert_fail ("InfoSlot->Class == RD && \"Wrong class for virtual base info!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 879, __PRETTY_FUNCTION__))
;
880 return InfoSlot;
881 }
882
883 // We don't, create it.
884 InfoSlot = new (BaseSubobjectInfoAllocator.Allocate()) BaseSubobjectInfo;
885 Info = InfoSlot;
886 } else {
887 Info = new (BaseSubobjectInfoAllocator.Allocate()) BaseSubobjectInfo;
888 }
889
890 Info->Class = RD;
891 Info->IsVirtual = IsVirtual;
892 Info->Derived = nullptr;
893 Info->PrimaryVirtualBaseInfo = nullptr;
894
895 const CXXRecordDecl *PrimaryVirtualBase = nullptr;
896 BaseSubobjectInfo *PrimaryVirtualBaseInfo = nullptr;
897
898 // Check if this base has a primary virtual base.
899 if (RD->getNumVBases()) {
900 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
901 if (Layout.isPrimaryBaseVirtual()) {
902 // This base does have a primary virtual base.
903 PrimaryVirtualBase = Layout.getPrimaryBase();
904 assert(PrimaryVirtualBase && "Didn't have a primary virtual base!")((PrimaryVirtualBase && "Didn't have a primary virtual base!"
) ? static_cast<void> (0) : __assert_fail ("PrimaryVirtualBase && \"Didn't have a primary virtual base!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 904, __PRETTY_FUNCTION__))
;
905
906 // Now check if we have base subobject info about this primary base.
907 PrimaryVirtualBaseInfo = VirtualBaseInfo.lookup(PrimaryVirtualBase);
908
909 if (PrimaryVirtualBaseInfo) {
910 if (PrimaryVirtualBaseInfo->Derived) {
911 // We did have info about this primary base, and it turns out that it
912 // has already been claimed as a primary virtual base for another
913 // base.
914 PrimaryVirtualBase = nullptr;
915 } else {
916 // We can claim this base as our primary base.
917 Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
918 PrimaryVirtualBaseInfo->Derived = Info;
919 }
920 }
921 }
922 }
923
924 // Now go through all direct bases.
925 for (const auto &I : RD->bases()) {
926 bool IsVirtual = I.isVirtual();
927
928 const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
929
930 Info->Bases.push_back(ComputeBaseSubobjectInfo(BaseDecl, IsVirtual, Info));
931 }
932
933 if (PrimaryVirtualBase && !PrimaryVirtualBaseInfo) {
934 // Traversing the bases must have created the base info for our primary
935 // virtual base.
936 PrimaryVirtualBaseInfo = VirtualBaseInfo.lookup(PrimaryVirtualBase);
937 assert(PrimaryVirtualBaseInfo &&((PrimaryVirtualBaseInfo && "Did not create a primary virtual base!"
) ? static_cast<void> (0) : __assert_fail ("PrimaryVirtualBaseInfo && \"Did not create a primary virtual base!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 938, __PRETTY_FUNCTION__))
938 "Did not create a primary virtual base!")((PrimaryVirtualBaseInfo && "Did not create a primary virtual base!"
) ? static_cast<void> (0) : __assert_fail ("PrimaryVirtualBaseInfo && \"Did not create a primary virtual base!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 938, __PRETTY_FUNCTION__))
;
939
940 // Claim the primary virtual base as our primary virtual base.
941 Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
942 PrimaryVirtualBaseInfo->Derived = Info;
943 }
944
945 return Info;
946}
947
948void ItaniumRecordLayoutBuilder::ComputeBaseSubobjectInfo(
949 const CXXRecordDecl *RD) {
950 for (const auto &I : RD->bases()) {
951 bool IsVirtual = I.isVirtual();
952
953 const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
954
955 // Compute the base subobject info for this base.
956 BaseSubobjectInfo *Info = ComputeBaseSubobjectInfo(BaseDecl, IsVirtual,
957 nullptr);
958
959 if (IsVirtual) {
960 // ComputeBaseInfo has already added this base for us.
961 assert(VirtualBaseInfo.count(BaseDecl) &&((VirtualBaseInfo.count(BaseDecl) && "Did not add virtual base!"
) ? static_cast<void> (0) : __assert_fail ("VirtualBaseInfo.count(BaseDecl) && \"Did not add virtual base!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 962, __PRETTY_FUNCTION__))
962 "Did not add virtual base!")((VirtualBaseInfo.count(BaseDecl) && "Did not add virtual base!"
) ? static_cast<void> (0) : __assert_fail ("VirtualBaseInfo.count(BaseDecl) && \"Did not add virtual base!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 962, __PRETTY_FUNCTION__))
;
963 } else {
964 // Add the base info to the map of non-virtual bases.
965 assert(!NonVirtualBaseInfo.count(BaseDecl) &&((!NonVirtualBaseInfo.count(BaseDecl) && "Non-virtual base already exists!"
) ? static_cast<void> (0) : __assert_fail ("!NonVirtualBaseInfo.count(BaseDecl) && \"Non-virtual base already exists!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 966, __PRETTY_FUNCTION__))
966 "Non-virtual base already exists!")((!NonVirtualBaseInfo.count(BaseDecl) && "Non-virtual base already exists!"
) ? static_cast<void> (0) : __assert_fail ("!NonVirtualBaseInfo.count(BaseDecl) && \"Non-virtual base already exists!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 966, __PRETTY_FUNCTION__))
;
967 NonVirtualBaseInfo.insert(std::make_pair(BaseDecl, Info));
968 }
969 }
970}
971
972void ItaniumRecordLayoutBuilder::EnsureVTablePointerAlignment(
973 CharUnits UnpackedBaseAlign) {
974 CharUnits BaseAlign = Packed ? CharUnits::One() : UnpackedBaseAlign;
975
976 // The maximum field alignment overrides base align.
977 if (!MaxFieldAlignment.isZero()) {
978 BaseAlign = std::min(BaseAlign, MaxFieldAlignment);
979 UnpackedBaseAlign = std::min(UnpackedBaseAlign, MaxFieldAlignment);
980 }
981
982 // Round up the current record size to pointer alignment.
983 setSize(getSize().alignTo(BaseAlign));
984 setDataSize(getSize());
985
986 // Update the alignment.
987 UpdateAlignment(BaseAlign, UnpackedBaseAlign);
988}
989
990void ItaniumRecordLayoutBuilder::LayoutNonVirtualBases(
991 const CXXRecordDecl *RD) {
992 // Then, determine the primary base class.
993 DeterminePrimaryBase(RD);
994
995 // Compute base subobject info.
996 ComputeBaseSubobjectInfo(RD);
997
998 // If we have a primary base class, lay it out.
999 if (PrimaryBase) {
1000 if (PrimaryBaseIsVirtual) {
1001 // If the primary virtual base was a primary virtual base of some other
1002 // base class we'll have to steal it.
1003 BaseSubobjectInfo *PrimaryBaseInfo = VirtualBaseInfo.lookup(PrimaryBase);
1004 PrimaryBaseInfo->Derived = nullptr;
1005
1006 // We have a virtual primary base, insert it as an indirect primary base.
1007 IndirectPrimaryBases.insert(PrimaryBase);
1008
1009 assert(!VisitedVirtualBases.count(PrimaryBase) &&((!VisitedVirtualBases.count(PrimaryBase) && "vbase already visited!"
) ? static_cast<void> (0) : __assert_fail ("!VisitedVirtualBases.count(PrimaryBase) && \"vbase already visited!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1010, __PRETTY_FUNCTION__))
1010 "vbase already visited!")((!VisitedVirtualBases.count(PrimaryBase) && "vbase already visited!"
) ? static_cast<void> (0) : __assert_fail ("!VisitedVirtualBases.count(PrimaryBase) && \"vbase already visited!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1010, __PRETTY_FUNCTION__))
;
1011 VisitedVirtualBases.insert(PrimaryBase);
1012
1013 LayoutVirtualBase(PrimaryBaseInfo);
1014 } else {
1015 BaseSubobjectInfo *PrimaryBaseInfo =
1016 NonVirtualBaseInfo.lookup(PrimaryBase);
1017 assert(PrimaryBaseInfo &&((PrimaryBaseInfo && "Did not find base info for non-virtual primary base!"
) ? static_cast<void> (0) : __assert_fail ("PrimaryBaseInfo && \"Did not find base info for non-virtual primary base!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1018, __PRETTY_FUNCTION__))
1018 "Did not find base info for non-virtual primary base!")((PrimaryBaseInfo && "Did not find base info for non-virtual primary base!"
) ? static_cast<void> (0) : __assert_fail ("PrimaryBaseInfo && \"Did not find base info for non-virtual primary base!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1018, __PRETTY_FUNCTION__))
;
1019
1020 LayoutNonVirtualBase(PrimaryBaseInfo);
1021 }
1022
1023 // If this class needs a vtable/vf-table and didn't get one from a
1024 // primary base, add it in now.
1025 } else if (RD->isDynamicClass()) {
1026 assert(DataSize == 0 && "Vtable pointer must be at offset zero!")((DataSize == 0 && "Vtable pointer must be at offset zero!"
) ? static_cast<void> (0) : __assert_fail ("DataSize == 0 && \"Vtable pointer must be at offset zero!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1026, __PRETTY_FUNCTION__))
;
1027 CharUnits PtrWidth =
1028 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
1029 CharUnits PtrAlign =
1030 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(0));
1031 EnsureVTablePointerAlignment(PtrAlign);
1032 HasOwnVFPtr = true;
1033 setSize(getSize() + PtrWidth);
1034 setDataSize(getSize());
1035 }
1036
1037 // Now lay out the non-virtual bases.
1038 for (const auto &I : RD->bases()) {
1039
1040 // Ignore virtual bases.
1041 if (I.isVirtual())
1042 continue;
1043
1044 const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
1045
1046 // Skip the primary base, because we've already laid it out. The
1047 // !PrimaryBaseIsVirtual check is required because we might have a
1048 // non-virtual base of the same type as a primary virtual base.
1049 if (BaseDecl == PrimaryBase && !PrimaryBaseIsVirtual)
1050 continue;
1051
1052 // Lay out the base.
1053 BaseSubobjectInfo *BaseInfo = NonVirtualBaseInfo.lookup(BaseDecl);
1054 assert(BaseInfo && "Did not find base info for non-virtual base!")((BaseInfo && "Did not find base info for non-virtual base!"
) ? static_cast<void> (0) : __assert_fail ("BaseInfo && \"Did not find base info for non-virtual base!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1054, __PRETTY_FUNCTION__))
;
1055
1056 LayoutNonVirtualBase(BaseInfo);
1057 }
1058}
1059
1060void ItaniumRecordLayoutBuilder::LayoutNonVirtualBase(
1061 const BaseSubobjectInfo *Base) {
1062 // Layout the base.
1063 CharUnits Offset = LayoutBase(Base);
1064
1065 // Add its base class offset.
1066 assert(!Bases.count(Base->Class) && "base offset already exists!")((!Bases.count(Base->Class) && "base offset already exists!"
) ? static_cast<void> (0) : __assert_fail ("!Bases.count(Base->Class) && \"base offset already exists!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1066, __PRETTY_FUNCTION__))
;
1067 Bases.insert(std::make_pair(Base->Class, Offset));
1068
1069 AddPrimaryVirtualBaseOffsets(Base, Offset);
1070}
1071
1072void ItaniumRecordLayoutBuilder::AddPrimaryVirtualBaseOffsets(
1073 const BaseSubobjectInfo *Info, CharUnits Offset) {
1074 // This base isn't interesting, it has no virtual bases.
1075 if (!Info->Class->getNumVBases())
1076 return;
1077
1078 // First, check if we have a virtual primary base to add offsets for.
1079 if (Info->PrimaryVirtualBaseInfo) {
1080 assert(Info->PrimaryVirtualBaseInfo->IsVirtual &&((Info->PrimaryVirtualBaseInfo->IsVirtual && "Primary virtual base is not virtual!"
) ? static_cast<void> (0) : __assert_fail ("Info->PrimaryVirtualBaseInfo->IsVirtual && \"Primary virtual base is not virtual!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1081, __PRETTY_FUNCTION__))
1081 "Primary virtual base is not virtual!")((Info->PrimaryVirtualBaseInfo->IsVirtual && "Primary virtual base is not virtual!"
) ? static_cast<void> (0) : __assert_fail ("Info->PrimaryVirtualBaseInfo->IsVirtual && \"Primary virtual base is not virtual!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1081, __PRETTY_FUNCTION__))
;
1082 if (Info->PrimaryVirtualBaseInfo->Derived == Info) {
1083 // Add the offset.
1084 assert(!VBases.count(Info->PrimaryVirtualBaseInfo->Class) &&((!VBases.count(Info->PrimaryVirtualBaseInfo->Class) &&
"primary vbase offset already exists!") ? static_cast<void
> (0) : __assert_fail ("!VBases.count(Info->PrimaryVirtualBaseInfo->Class) && \"primary vbase offset already exists!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1085, __PRETTY_FUNCTION__))
1085 "primary vbase offset already exists!")((!VBases.count(Info->PrimaryVirtualBaseInfo->Class) &&
"primary vbase offset already exists!") ? static_cast<void
> (0) : __assert_fail ("!VBases.count(Info->PrimaryVirtualBaseInfo->Class) && \"primary vbase offset already exists!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1085, __PRETTY_FUNCTION__))
;
1086 VBases.insert(std::make_pair(Info->PrimaryVirtualBaseInfo->Class,
1087 ASTRecordLayout::VBaseInfo(Offset, false)));
1088
1089 // Traverse the primary virtual base.
1090 AddPrimaryVirtualBaseOffsets(Info->PrimaryVirtualBaseInfo, Offset);
1091 }
1092 }
1093
1094 // Now go through all direct non-virtual bases.
1095 const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
1096 for (const BaseSubobjectInfo *Base : Info->Bases) {
1097 if (Base->IsVirtual)
1098 continue;
1099
1100 CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
1101 AddPrimaryVirtualBaseOffsets(Base, BaseOffset);
1102 }
1103}
1104
1105void ItaniumRecordLayoutBuilder::LayoutVirtualBases(
1106 const CXXRecordDecl *RD, const CXXRecordDecl *MostDerivedClass) {
1107 const CXXRecordDecl *PrimaryBase;
1108 bool PrimaryBaseIsVirtual;
1109
1110 if (MostDerivedClass == RD) {
12
Taking true branch
1111 PrimaryBase = this->PrimaryBase;
1112 PrimaryBaseIsVirtual = this->PrimaryBaseIsVirtual;
1113 } else {
1114 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1115 PrimaryBase = Layout.getPrimaryBase();
1116 PrimaryBaseIsVirtual = Layout.isPrimaryBaseVirtual();
1117 }
1118
1119 for (const CXXBaseSpecifier &Base : RD->bases()) {
13
Assuming '__begin1' is not equal to '__end1'
1120 assert(!Base.getType()->isDependentType() &&((!Base.getType()->isDependentType() && "Cannot layout class with dependent bases."
) ? static_cast<void> (0) : __assert_fail ("!Base.getType()->isDependentType() && \"Cannot layout class with dependent bases.\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1121, __PRETTY_FUNCTION__))
1121 "Cannot layout class with dependent bases.")((!Base.getType()->isDependentType() && "Cannot layout class with dependent bases."
) ? static_cast<void> (0) : __assert_fail ("!Base.getType()->isDependentType() && \"Cannot layout class with dependent bases.\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1121, __PRETTY_FUNCTION__))
;
1122
1123 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
14
'BaseDecl' initialized here
1124
1125 if (Base.isVirtual()) {
15
Assuming the condition is true
16
Taking true branch
1126 if (PrimaryBase != BaseDecl || !PrimaryBaseIsVirtual) {
17
Assuming 'PrimaryBase' is equal to 'BaseDecl'
18
Assuming pointer value is null
19
Assuming 'PrimaryBaseIsVirtual' is not equal to 0
20
Taking false branch
1127 bool IndirectPrimaryBase = IndirectPrimaryBases.count(BaseDecl);
1128
1129 // Only lay out the virtual base if it's not an indirect primary base.
1130 if (!IndirectPrimaryBase) {
1131 // Only visit virtual bases once.
1132 if (!VisitedVirtualBases.insert(BaseDecl).second)
1133 continue;
1134
1135 const BaseSubobjectInfo *BaseInfo = VirtualBaseInfo.lookup(BaseDecl);
1136 assert(BaseInfo && "Did not find virtual base info!")((BaseInfo && "Did not find virtual base info!") ? static_cast
<void> (0) : __assert_fail ("BaseInfo && \"Did not find virtual base info!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1136, __PRETTY_FUNCTION__))
;
1137 LayoutVirtualBase(BaseInfo);
1138 }
1139 }
1140 }
1141
1142 if (!BaseDecl->getNumVBases()) {
21
Called C++ object pointer is null
1143 // This base isn't interesting since it doesn't have any virtual bases.
1144 continue;
1145 }
1146
1147 LayoutVirtualBases(BaseDecl, MostDerivedClass);
1148 }
1149}
1150
1151void ItaniumRecordLayoutBuilder::LayoutVirtualBase(
1152 const BaseSubobjectInfo *Base) {
1153 assert(!Base->Derived && "Trying to lay out a primary virtual base!")((!Base->Derived && "Trying to lay out a primary virtual base!"
) ? static_cast<void> (0) : __assert_fail ("!Base->Derived && \"Trying to lay out a primary virtual base!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1153, __PRETTY_FUNCTION__))
;
1154
1155 // Layout the base.
1156 CharUnits Offset = LayoutBase(Base);
1157
1158 // Add its base class offset.
1159 assert(!VBases.count(Base->Class) && "vbase offset already exists!")((!VBases.count(Base->Class) && "vbase offset already exists!"
) ? static_cast<void> (0) : __assert_fail ("!VBases.count(Base->Class) && \"vbase offset already exists!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1159, __PRETTY_FUNCTION__))
;
1160 VBases.insert(std::make_pair(Base->Class,
1161 ASTRecordLayout::VBaseInfo(Offset, false)));
1162
1163 AddPrimaryVirtualBaseOffsets(Base, Offset);
1164}
1165
1166CharUnits
1167ItaniumRecordLayoutBuilder::LayoutBase(const BaseSubobjectInfo *Base) {
1168 const ASTRecordLayout &Layout = Context.getASTRecordLayout(Base->Class);
1169
1170
1171 CharUnits Offset;
1172
1173 // Query the external layout to see if it provides an offset.
1174 bool HasExternalLayout = false;
1175 if (UseExternalLayout) {
1176 if (Base->IsVirtual)
1177 HasExternalLayout = External.getExternalNVBaseOffset(Base->Class, Offset);
1178 else
1179 HasExternalLayout = External.getExternalVBaseOffset(Base->Class, Offset);
1180 }
1181
1182 // Clang <= 6 incorrectly applied the 'packed' attribute to base classes.
1183 // Per GCC's documentation, it only applies to non-static data members.
1184 CharUnits UnpackedBaseAlign = Layout.getNonVirtualAlignment();
1185 CharUnits BaseAlign =
1186 (Packed && ((Context.getLangOpts().getClangABICompat() <=
1187 LangOptions::ClangABI::Ver6) ||
1188 Context.getTargetInfo().getTriple().isPS4()))
1189 ? CharUnits::One()
1190 : UnpackedBaseAlign;
1191
1192 // If we have an empty base class, try to place it at offset 0.
1193 if (Base->Class->isEmpty() &&
1194 (!HasExternalLayout || Offset == CharUnits::Zero()) &&
1195 EmptySubobjects->CanPlaceBaseAtOffset(Base, CharUnits::Zero())) {
1196 setSize(std::max(getSize(), Layout.getSize()));
1197 UpdateAlignment(BaseAlign, UnpackedBaseAlign);
1198
1199 return CharUnits::Zero();
1200 }
1201
1202 // The maximum field alignment overrides base align.
1203 if (!MaxFieldAlignment.isZero()) {
1204 BaseAlign = std::min(BaseAlign, MaxFieldAlignment);
1205 UnpackedBaseAlign = std::min(UnpackedBaseAlign, MaxFieldAlignment);
1206 }
1207
1208 if (!HasExternalLayout) {
1209 // Round up the current record size to the base's alignment boundary.
1210 Offset = getDataSize().alignTo(BaseAlign);
1211
1212 // Try to place the base.
1213 while (!EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset))
1214 Offset += BaseAlign;
1215 } else {
1216 bool Allowed = EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset);
1217 (void)Allowed;
1218 assert(Allowed && "Base subobject externally placed at overlapping offset")((Allowed && "Base subobject externally placed at overlapping offset"
) ? static_cast<void> (0) : __assert_fail ("Allowed && \"Base subobject externally placed at overlapping offset\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1218, __PRETTY_FUNCTION__))
;
1219
1220 if (InferAlignment && Offset < getDataSize().alignTo(BaseAlign)) {
1221 // The externally-supplied base offset is before the base offset we
1222 // computed. Assume that the structure is packed.
1223 Alignment = CharUnits::One();
1224 InferAlignment = false;
1225 }
1226 }
1227
1228 if (!Base->Class->isEmpty()) {
1229 // Update the data size.
1230 setDataSize(Offset + Layout.getNonVirtualSize());
1231
1232 setSize(std::max(getSize(), getDataSize()));
1233 } else
1234 setSize(std::max(getSize(), Offset + Layout.getSize()));
1235
1236 // Remember max struct/class alignment.
1237 UpdateAlignment(BaseAlign, UnpackedBaseAlign);
1238
1239 return Offset;
1240}
1241
1242void ItaniumRecordLayoutBuilder::InitializeLayout(const Decl *D) {
1243 if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
1244 IsUnion = RD->isUnion();
1245 IsMsStruct = RD->isMsStruct(Context);
1246 }
1247
1248 Packed = D->hasAttr<PackedAttr>();
1249
1250 // Honor the default struct packing maximum alignment flag.
1251 if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct) {
1252 MaxFieldAlignment = CharUnits::fromQuantity(DefaultMaxFieldAlignment);
1253 }
1254
1255 // mac68k alignment supersedes maximum field alignment and attribute aligned,
1256 // and forces all structures to have 2-byte alignment. The IBM docs on it
1257 // allude to additional (more complicated) semantics, especially with regard
1258 // to bit-fields, but gcc appears not to follow that.
1259 if (D->hasAttr<AlignMac68kAttr>()) {
1260 IsMac68kAlign = true;
1261 MaxFieldAlignment = CharUnits::fromQuantity(2);
1262 Alignment = CharUnits::fromQuantity(2);
1263 } else {
1264 if (const MaxFieldAlignmentAttr *MFAA = D->getAttr<MaxFieldAlignmentAttr>())
1265 MaxFieldAlignment = Context.toCharUnitsFromBits(MFAA->getAlignment());
1266
1267 if (unsigned MaxAlign = D->getMaxAlignment())
1268 UpdateAlignment(Context.toCharUnitsFromBits(MaxAlign));
1269 }
1270
1271 // If there is an external AST source, ask it for the various offsets.
1272 if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
1273 if (ExternalASTSource *Source = Context.getExternalSource()) {
1274 UseExternalLayout = Source->layoutRecordType(
1275 RD, External.Size, External.Align, External.FieldOffsets,
1276 External.BaseOffsets, External.VirtualBaseOffsets);
1277
1278 // Update based on external alignment.
1279 if (UseExternalLayout) {
1280 if (External.Align > 0) {
1281 Alignment = Context.toCharUnitsFromBits(External.Align);
1282 } else {
1283 // The external source didn't have alignment information; infer it.
1284 InferAlignment = true;
1285 }
1286 }
1287 }
1288}
1289
1290void ItaniumRecordLayoutBuilder::Layout(const RecordDecl *D) {
1291 InitializeLayout(D);
1292 LayoutFields(D);
1293
1294 // Finally, round the size of the total struct up to the alignment of the
1295 // struct itself.
1296 FinishLayout(D);
1297}
1298
1299void ItaniumRecordLayoutBuilder::Layout(const CXXRecordDecl *RD) {
1300 InitializeLayout(RD);
1301
1302 // Lay out the vtable and the non-virtual bases.
1303 LayoutNonVirtualBases(RD);
1304
1305 LayoutFields(RD);
1306
1307 NonVirtualSize = Context.toCharUnitsFromBits(
1308 llvm::alignTo(getSizeInBits(), Context.getTargetInfo().getCharAlign()));
1309 NonVirtualAlignment = Alignment;
1310
1311 // Lay out the virtual bases and add the primary virtual base offsets.
1312 LayoutVirtualBases(RD, RD);
11
Calling 'ItaniumRecordLayoutBuilder::LayoutVirtualBases'
1313
1314 // Finally, round the size of the total struct up to the alignment
1315 // of the struct itself.
1316 FinishLayout(RD);
1317
1318#ifndef NDEBUG
1319 // Check that we have base offsets for all bases.
1320 for (const CXXBaseSpecifier &Base : RD->bases()) {
1321 if (Base.isVirtual())
1322 continue;
1323
1324 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1325
1326 assert(Bases.count(BaseDecl) && "Did not find base offset!")((Bases.count(BaseDecl) && "Did not find base offset!"
) ? static_cast<void> (0) : __assert_fail ("Bases.count(BaseDecl) && \"Did not find base offset!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1326, __PRETTY_FUNCTION__))
;
1327 }
1328
1329 // And all virtual bases.
1330 for (const CXXBaseSpecifier &Base : RD->vbases()) {
1331 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1332
1333 assert(VBases.count(BaseDecl) && "Did not find base offset!")((VBases.count(BaseDecl) && "Did not find base offset!"
) ? static_cast<void> (0) : __assert_fail ("VBases.count(BaseDecl) && \"Did not find base offset!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1333, __PRETTY_FUNCTION__))
;
1334 }
1335#endif
1336}
1337
1338void ItaniumRecordLayoutBuilder::Layout(const ObjCInterfaceDecl *D) {
1339 if (ObjCInterfaceDecl *SD = D->getSuperClass()) {
1340 const ASTRecordLayout &SL = Context.getASTObjCInterfaceLayout(SD);
1341
1342 UpdateAlignment(SL.getAlignment());
1343
1344 // We start laying out ivars not at the end of the superclass
1345 // structure, but at the next byte following the last field.
1346 setSize(SL.getDataSize());
1347 setDataSize(getSize());
1348 }
1349
1350 InitializeLayout(D);
1351 // Layout each ivar sequentially.
1352 for (const ObjCIvarDecl *IVD = D->all_declared_ivar_begin(); IVD;
1353 IVD = IVD->getNextIvar())
1354 LayoutField(IVD, false);
1355
1356 // Finally, round the size of the total struct up to the alignment of the
1357 // struct itself.
1358 FinishLayout(D);
1359}
1360
1361void ItaniumRecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
1362 // Layout each field, for now, just sequentially, respecting alignment. In
1363 // the future, this will need to be tweakable by targets.
1364 bool InsertExtraPadding = D->mayInsertExtraPadding(/*EmitRemark=*/true);
1365 bool HasFlexibleArrayMember = D->hasFlexibleArrayMember();
1366 for (auto I = D->field_begin(), End = D->field_end(); I != End; ++I) {
1367 auto Next(I);
1368 ++Next;
1369 LayoutField(*I,
1370 InsertExtraPadding && (Next != End || !HasFlexibleArrayMember));
1371 }
1372}
1373
1374// Rounds the specified size to have it a multiple of the char size.
1375static uint64_t
1376roundUpSizeToCharAlignment(uint64_t Size,
1377 const ASTContext &Context) {
1378 uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
1379 return llvm::alignTo(Size, CharAlignment);
1380}
1381
1382void ItaniumRecordLayoutBuilder::LayoutWideBitField(uint64_t FieldSize,
1383 uint64_t TypeSize,
1384 bool FieldPacked,
1385 const FieldDecl *D) {
1386 assert(Context.getLangOpts().CPlusPlus &&((Context.getLangOpts().CPlusPlus && "Can only have wide bit-fields in C++!"
) ? static_cast<void> (0) : __assert_fail ("Context.getLangOpts().CPlusPlus && \"Can only have wide bit-fields in C++!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1387, __PRETTY_FUNCTION__))
1387 "Can only have wide bit-fields in C++!")((Context.getLangOpts().CPlusPlus && "Can only have wide bit-fields in C++!"
) ? static_cast<void> (0) : __assert_fail ("Context.getLangOpts().CPlusPlus && \"Can only have wide bit-fields in C++!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1387, __PRETTY_FUNCTION__))
;
1388
1389 // Itanium C++ ABI 2.4:
1390 // If sizeof(T)*8 < n, let T' be the largest integral POD type with
1391 // sizeof(T')*8 <= n.
1392
1393 QualType IntegralPODTypes[] = {
1394 Context.UnsignedCharTy, Context.UnsignedShortTy, Context.UnsignedIntTy,
1395 Context.UnsignedLongTy, Context.UnsignedLongLongTy
1396 };
1397
1398 QualType Type;
1399 for (const QualType &QT : IntegralPODTypes) {
1400 uint64_t Size = Context.getTypeSize(QT);
1401
1402 if (Size > FieldSize)
1403 break;
1404
1405 Type = QT;
1406 }
1407 assert(!Type.isNull() && "Did not find a type!")((!Type.isNull() && "Did not find a type!") ? static_cast
<void> (0) : __assert_fail ("!Type.isNull() && \"Did not find a type!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1407, __PRETTY_FUNCTION__))
;
1408
1409 CharUnits TypeAlign = Context.getTypeAlignInChars(Type);
1410
1411 // We're not going to use any of the unfilled bits in the last byte.
1412 UnfilledBitsInLastUnit = 0;
1413 LastBitfieldTypeSize = 0;
1414
1415 uint64_t FieldOffset;
1416 uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;
1417
1418 if (IsUnion) {
1419 uint64_t RoundedFieldSize = roundUpSizeToCharAlignment(FieldSize,
1420 Context);
1421 setDataSize(std::max(getDataSizeInBits(), RoundedFieldSize));
1422 FieldOffset = 0;
1423 } else {
1424 // The bitfield is allocated starting at the next offset aligned
1425 // appropriately for T', with length n bits.
1426 FieldOffset = llvm::alignTo(getDataSizeInBits(), Context.toBits(TypeAlign));
1427
1428 uint64_t NewSizeInBits = FieldOffset + FieldSize;
1429
1430 setDataSize(
1431 llvm::alignTo(NewSizeInBits, Context.getTargetInfo().getCharAlign()));
1432 UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;
1433 }
1434
1435 // Place this field at the current location.
1436 FieldOffsets.push_back(FieldOffset);
1437
1438 CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, FieldOffset,
1439 Context.toBits(TypeAlign), FieldPacked, D);
1440
1441 // Update the size.
1442 setSize(std::max(getSizeInBits(), getDataSizeInBits()));
1443
1444 // Remember max struct/class alignment.
1445 UpdateAlignment(TypeAlign);
1446}
1447
1448void ItaniumRecordLayoutBuilder::LayoutBitField(const FieldDecl *D) {
1449 bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
1450 uint64_t FieldSize = D->getBitWidthValue(Context);
1451 TypeInfo FieldInfo = Context.getTypeInfo(D->getType());
1452 uint64_t TypeSize = FieldInfo.Width;
1453 unsigned FieldAlign = FieldInfo.Align;
1454
1455 // UnfilledBitsInLastUnit is the difference between the end of the
1456 // last allocated bitfield (i.e. the first bit offset available for
1457 // bitfields) and the end of the current data size in bits (i.e. the
1458 // first bit offset available for non-bitfields). The current data
1459 // size in bits is always a multiple of the char size; additionally,
1460 // for ms_struct records it's also a multiple of the
1461 // LastBitfieldTypeSize (if set).
1462
1463 // The struct-layout algorithm is dictated by the platform ABI,
1464 // which in principle could use almost any rules it likes. In
1465 // practice, UNIXy targets tend to inherit the algorithm described
1466 // in the System V generic ABI. The basic bitfield layout rule in
1467 // System V is to place bitfields at the next available bit offset
1468 // where the entire bitfield would fit in an aligned storage unit of
1469 // the declared type; it's okay if an earlier or later non-bitfield
1470 // is allocated in the same storage unit. However, some targets
1471 // (those that !useBitFieldTypeAlignment(), e.g. ARM APCS) don't
1472 // require this storage unit to be aligned, and therefore always put
1473 // the bitfield at the next available bit offset.
1474
1475 // ms_struct basically requests a complete replacement of the
1476 // platform ABI's struct-layout algorithm, with the high-level goal
1477 // of duplicating MSVC's layout. For non-bitfields, this follows
1478 // the standard algorithm. The basic bitfield layout rule is to
1479 // allocate an entire unit of the bitfield's declared type
1480 // (e.g. 'unsigned long'), then parcel it up among successive
1481 // bitfields whose declared types have the same size, making a new
1482 // unit as soon as the last can no longer store the whole value.
1483 // Since it completely replaces the platform ABI's algorithm,
1484 // settings like !useBitFieldTypeAlignment() do not apply.
1485
1486 // A zero-width bitfield forces the use of a new storage unit for
1487 // later bitfields. In general, this occurs by rounding up the
1488 // current size of the struct as if the algorithm were about to
1489 // place a non-bitfield of the field's formal type. Usually this
1490 // does not change the alignment of the struct itself, but it does
1491 // on some targets (those that useZeroLengthBitfieldAlignment(),
1492 // e.g. ARM). In ms_struct layout, zero-width bitfields are
1493 // ignored unless they follow a non-zero-width bitfield.
1494
1495 // A field alignment restriction (e.g. from #pragma pack) or
1496 // specification (e.g. from __attribute__((aligned))) changes the
1497 // formal alignment of the field. For System V, this alters the
1498 // required alignment of the notional storage unit that must contain
1499 // the bitfield. For ms_struct, this only affects the placement of
1500 // new storage units. In both cases, the effect of #pragma pack is
1501 // ignored on zero-width bitfields.
1502
1503 // On System V, a packed field (e.g. from #pragma pack or
1504 // __attribute__((packed))) always uses the next available bit
1505 // offset.
1506
1507 // In an ms_struct struct, the alignment of a fundamental type is
1508 // always equal to its size. This is necessary in order to mimic
1509 // the i386 alignment rules on targets which might not fully align
1510 // all types (e.g. Darwin PPC32, where alignof(long long) == 4).
1511
1512 // First, some simple bookkeeping to perform for ms_struct structs.
1513 if (IsMsStruct) {
1514 // The field alignment for integer types is always the size.
1515 FieldAlign = TypeSize;
1516
1517 // If the previous field was not a bitfield, or was a bitfield
1518 // with a different storage unit size, or if this field doesn't fit into
1519 // the current storage unit, we're done with that storage unit.
1520 if (LastBitfieldTypeSize != TypeSize ||
1521 UnfilledBitsInLastUnit < FieldSize) {
1522 // Also, ignore zero-length bitfields after non-bitfields.
1523 if (!LastBitfieldTypeSize && !FieldSize)
1524 FieldAlign = 1;
1525
1526 UnfilledBitsInLastUnit = 0;
1527 LastBitfieldTypeSize = 0;
1528 }
1529 }
1530
1531 // If the field is wider than its declared type, it follows
1532 // different rules in all cases.
1533 if (FieldSize > TypeSize) {
1534 LayoutWideBitField(FieldSize, TypeSize, FieldPacked, D);
1535 return;
1536 }
1537
1538 // Compute the next available bit offset.
1539 uint64_t FieldOffset =
1540 IsUnion ? 0 : (getDataSizeInBits() - UnfilledBitsInLastUnit);
1541
1542 // Handle targets that don't honor bitfield type alignment.
1543 if (!IsMsStruct && !Context.getTargetInfo().useBitFieldTypeAlignment()) {
1544 // Some such targets do honor it on zero-width bitfields.
1545 if (FieldSize == 0 &&
1546 Context.getTargetInfo().useZeroLengthBitfieldAlignment()) {
1547 // The alignment to round up to is the max of the field's natural
1548 // alignment and a target-specific fixed value (sometimes zero).
1549 unsigned ZeroLengthBitfieldBoundary =
1550 Context.getTargetInfo().getZeroLengthBitfieldBoundary();
1551 FieldAlign = std::max(FieldAlign, ZeroLengthBitfieldBoundary);
1552
1553 // If that doesn't apply, just ignore the field alignment.
1554 } else {
1555 FieldAlign = 1;
1556 }
1557 }
1558
1559 // Remember the alignment we would have used if the field were not packed.
1560 unsigned UnpackedFieldAlign = FieldAlign;
1561
1562 // Ignore the field alignment if the field is packed unless it has zero-size.
1563 if (!IsMsStruct && FieldPacked && FieldSize != 0)
1564 FieldAlign = 1;
1565
1566 // But, if there's an 'aligned' attribute on the field, honor that.
1567 unsigned ExplicitFieldAlign = D->getMaxAlignment();
1568 if (ExplicitFieldAlign) {
1569 FieldAlign = std::max(FieldAlign, ExplicitFieldAlign);
1570 UnpackedFieldAlign = std::max(UnpackedFieldAlign, ExplicitFieldAlign);
1571 }
1572
1573 // But, if there's a #pragma pack in play, that takes precedent over
1574 // even the 'aligned' attribute, for non-zero-width bitfields.
1575 unsigned MaxFieldAlignmentInBits = Context.toBits(MaxFieldAlignment);
1576 if (!MaxFieldAlignment.isZero() && FieldSize) {
1577 UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignmentInBits);
1578 if (FieldPacked)
1579 FieldAlign = UnpackedFieldAlign;
1580 else
1581 FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
1582 }
1583
1584 // But, ms_struct just ignores all of that in unions, even explicit
1585 // alignment attributes.
1586 if (IsMsStruct && IsUnion) {
1587 FieldAlign = UnpackedFieldAlign = 1;
1588 }
1589
1590 // For purposes of diagnostics, we're going to simultaneously
1591 // compute the field offsets that we would have used if we weren't
1592 // adding any alignment padding or if the field weren't packed.
1593 uint64_t UnpaddedFieldOffset = FieldOffset;
1594 uint64_t UnpackedFieldOffset = FieldOffset;
1595
1596 // Check if we need to add padding to fit the bitfield within an
1597 // allocation unit with the right size and alignment. The rules are
1598 // somewhat different here for ms_struct structs.
1599 if (IsMsStruct) {
1600 // If it's not a zero-width bitfield, and we can fit the bitfield
1601 // into the active storage unit (and we haven't already decided to
1602 // start a new storage unit), just do so, regardless of any other
1603 // other consideration. Otherwise, round up to the right alignment.
1604 if (FieldSize == 0 || FieldSize > UnfilledBitsInLastUnit) {
1605 FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
1606 UnpackedFieldOffset =
1607 llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
1608 UnfilledBitsInLastUnit = 0;
1609 }
1610
1611 } else {
1612 // #pragma pack, with any value, suppresses the insertion of padding.
1613 bool AllowPadding = MaxFieldAlignment.isZero();
1614
1615 // Compute the real offset.
1616 if (FieldSize == 0 ||
1617 (AllowPadding &&
1618 (FieldOffset & (FieldAlign-1)) + FieldSize > TypeSize)) {
1619 FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
1620 } else if (ExplicitFieldAlign &&
1621 (MaxFieldAlignmentInBits == 0 ||
1622 ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
1623 Context.getTargetInfo().useExplicitBitFieldAlignment()) {
1624 // TODO: figure it out what needs to be done on targets that don't honor
1625 // bit-field type alignment like ARM APCS ABI.
1626 FieldOffset = llvm::alignTo(FieldOffset, ExplicitFieldAlign);
1627 }
1628
1629 // Repeat the computation for diagnostic purposes.
1630 if (FieldSize == 0 ||
1631 (AllowPadding &&
1632 (UnpackedFieldOffset & (UnpackedFieldAlign-1)) + FieldSize > TypeSize))
1633 UnpackedFieldOffset =
1634 llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
1635 else if (ExplicitFieldAlign &&
1636 (MaxFieldAlignmentInBits == 0 ||
1637 ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
1638 Context.getTargetInfo().useExplicitBitFieldAlignment())
1639 UnpackedFieldOffset =
1640 llvm::alignTo(UnpackedFieldOffset, ExplicitFieldAlign);
1641 }
1642
1643 // If we're using external layout, give the external layout a chance
1644 // to override this information.
1645 if (UseExternalLayout)
1646 FieldOffset = updateExternalFieldOffset(D, FieldOffset);
1647
1648 // Okay, place the bitfield at the calculated offset.
1649 FieldOffsets.push_back(FieldOffset);
1650
1651 // Bookkeeping:
1652
1653 // Anonymous members don't affect the overall record alignment,
1654 // except on targets where they do.
1655 if (!IsMsStruct &&
1656 !Context.getTargetInfo().useZeroLengthBitfieldAlignment() &&
1657 !D->getIdentifier())
1658 FieldAlign = UnpackedFieldAlign = 1;
1659
1660 // Diagnose differences in layout due to padding or packing.
1661 if (!UseExternalLayout)
1662 CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, UnpackedFieldOffset,
1663 UnpackedFieldAlign, FieldPacked, D);
1664
1665 // Update DataSize to include the last byte containing (part of) the bitfield.
1666
1667 // For unions, this is just a max operation, as usual.
1668 if (IsUnion) {
1669 // For ms_struct, allocate the entire storage unit --- unless this
1670 // is a zero-width bitfield, in which case just use a size of 1.
1671 uint64_t RoundedFieldSize;
1672 if (IsMsStruct) {
1673 RoundedFieldSize =
1674 (FieldSize ? TypeSize : Context.getTargetInfo().getCharWidth());
1675
1676 // Otherwise, allocate just the number of bytes required to store
1677 // the bitfield.
1678 } else {
1679 RoundedFieldSize = roundUpSizeToCharAlignment(FieldSize, Context);
1680 }
1681 setDataSize(std::max(getDataSizeInBits(), RoundedFieldSize));
1682
1683 // For non-zero-width bitfields in ms_struct structs, allocate a new
1684 // storage unit if necessary.
1685 } else if (IsMsStruct && FieldSize) {
1686 // We should have cleared UnfilledBitsInLastUnit in every case
1687 // where we changed storage units.
1688 if (!UnfilledBitsInLastUnit) {
1689 setDataSize(FieldOffset + TypeSize);
1690 UnfilledBitsInLastUnit = TypeSize;
1691 }
1692 UnfilledBitsInLastUnit -= FieldSize;
1693 LastBitfieldTypeSize = TypeSize;
1694
1695 // Otherwise, bump the data size up to include the bitfield,
1696 // including padding up to char alignment, and then remember how
1697 // bits we didn't use.
1698 } else {
1699 uint64_t NewSizeInBits = FieldOffset + FieldSize;
1700 uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
1701 setDataSize(llvm::alignTo(NewSizeInBits, CharAlignment));
1702 UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;
1703
1704 // The only time we can get here for an ms_struct is if this is a
1705 // zero-width bitfield, which doesn't count as anything for the
1706 // purposes of unfilled bits.
1707 LastBitfieldTypeSize = 0;
1708 }
1709
1710 // Update the size.
1711 setSize(std::max(getSizeInBits(), getDataSizeInBits()));
1712
1713 // Remember max struct/class alignment.
1714 UnadjustedAlignment =
1715 std::max(UnadjustedAlignment, Context.toCharUnitsFromBits(FieldAlign));
1716 UpdateAlignment(Context.toCharUnitsFromBits(FieldAlign),
1717 Context.toCharUnitsFromBits(UnpackedFieldAlign));
1718}
1719
1720void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D,
1721 bool InsertExtraPadding) {
1722 if (D->isBitField()) {
1723 LayoutBitField(D);
1724 return;
1725 }
1726
1727 uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;
1728
1729 // Reset the unfilled bits.
1730 UnfilledBitsInLastUnit = 0;
1731 LastBitfieldTypeSize = 0;
1732
1733 bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
1734 CharUnits FieldOffset =
1735 IsUnion ? CharUnits::Zero() : getDataSize();
1736 CharUnits FieldSize;
1737 CharUnits FieldAlign;
1738
1739 if (D->getType()->isIncompleteArrayType()) {
1740 // This is a flexible array member; we can't directly
1741 // query getTypeInfo about these, so we figure it out here.
1742 // Flexible array members don't have any size, but they
1743 // have to be aligned appropriately for their element type.
1744 FieldSize = CharUnits::Zero();
1745 const ArrayType* ATy = Context.getAsArrayType(D->getType());
1746 FieldAlign = Context.getTypeAlignInChars(ATy->getElementType());
1747 } else if (const ReferenceType *RT = D->getType()->getAs<ReferenceType>()) {
1748 unsigned AS = Context.getTargetAddressSpace(RT->getPointeeType());
1749 FieldSize =
1750 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(AS));
1751 FieldAlign =
1752 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(AS));
1753 } else {
1754 std::pair<CharUnits, CharUnits> FieldInfo =
1755 Context.getTypeInfoInChars(D->getType());
1756 FieldSize = FieldInfo.first;
1757 FieldAlign = FieldInfo.second;
1758
1759 if (IsMsStruct) {
1760 // If MS bitfield layout is required, figure out what type is being
1761 // laid out and align the field to the width of that type.
1762
1763 // Resolve all typedefs down to their base type and round up the field
1764 // alignment if necessary.
1765 QualType T = Context.getBaseElementType(D->getType());
1766 if (const BuiltinType *BTy = T->getAs<BuiltinType>()) {
1767 CharUnits TypeSize = Context.getTypeSizeInChars(BTy);
1768
1769 if (!llvm::isPowerOf2_64(TypeSize.getQuantity())) {
1770 assert(((!Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment
() && "Non PowerOf2 size in MSVC mode") ? static_cast
<void> (0) : __assert_fail ("!Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() && \"Non PowerOf2 size in MSVC mode\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1772, __PRETTY_FUNCTION__))
1771 !Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() &&((!Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment
() && "Non PowerOf2 size in MSVC mode") ? static_cast
<void> (0) : __assert_fail ("!Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() && \"Non PowerOf2 size in MSVC mode\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1772, __PRETTY_FUNCTION__))
1772 "Non PowerOf2 size in MSVC mode")((!Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment
() && "Non PowerOf2 size in MSVC mode") ? static_cast
<void> (0) : __assert_fail ("!Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() && \"Non PowerOf2 size in MSVC mode\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1772, __PRETTY_FUNCTION__))
;
1773 // Base types with sizes that aren't a power of two don't work
1774 // with the layout rules for MS structs. This isn't an issue in
1775 // MSVC itself since there are no such base data types there.
1776 // On e.g. x86_32 mingw and linux, long double is 12 bytes though.
1777 // Any structs involving that data type obviously can't be ABI
1778 // compatible with MSVC regardless of how it is laid out.
1779
1780 // Since ms_struct can be mass enabled (via a pragma or via the
1781 // -mms-bitfields command line parameter), this can trigger for
1782 // structs that don't actually need MSVC compatibility, so we
1783 // need to be able to sidestep the ms_struct layout for these types.
1784
1785 // Since the combination of -mms-bitfields together with structs
1786 // like max_align_t (which contains a long double) for mingw is
1787 // quite comon (and GCC handles it silently), just handle it
1788 // silently there. For other targets that have ms_struct enabled
1789 // (most probably via a pragma or attribute), trigger a diagnostic
1790 // that defaults to an error.
1791 if (!Context.getTargetInfo().getTriple().isWindowsGNUEnvironment())
1792 Diag(D->getLocation(), diag::warn_npot_ms_struct);
1793 }
1794 if (TypeSize > FieldAlign &&
1795 llvm::isPowerOf2_64(TypeSize.getQuantity()))
1796 FieldAlign = TypeSize;
1797 }
1798 }
1799 }
1800
1801 // The align if the field is not packed. This is to check if the attribute
1802 // was unnecessary (-Wpacked).
1803 CharUnits UnpackedFieldAlign = FieldAlign;
1804 CharUnits UnpackedFieldOffset = FieldOffset;
1805
1806 if (FieldPacked)
1807 FieldAlign = CharUnits::One();
1808 CharUnits MaxAlignmentInChars =
1809 Context.toCharUnitsFromBits(D->getMaxAlignment());
1810 FieldAlign = std::max(FieldAlign, MaxAlignmentInChars);
1811 UnpackedFieldAlign = std::max(UnpackedFieldAlign, MaxAlignmentInChars);
1812
1813 // The maximum field alignment overrides the aligned attribute.
1814 if (!MaxFieldAlignment.isZero()) {
1815 FieldAlign = std::min(FieldAlign, MaxFieldAlignment);
1816 UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignment);
1817 }
1818
1819 // Round up the current record size to the field's alignment boundary.
1820 FieldOffset = FieldOffset.alignTo(FieldAlign);
1821 UnpackedFieldOffset = UnpackedFieldOffset.alignTo(UnpackedFieldAlign);
1822
1823 if (UseExternalLayout) {
1824 FieldOffset = Context.toCharUnitsFromBits(
1825 updateExternalFieldOffset(D, Context.toBits(FieldOffset)));
1826
1827 if (!IsUnion && EmptySubobjects) {
1828 // Record the fact that we're placing a field at this offset.
1829 bool Allowed = EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset);
1830 (void)Allowed;
1831 assert(Allowed && "Externally-placed field cannot be placed here")((Allowed && "Externally-placed field cannot be placed here"
) ? static_cast<void> (0) : __assert_fail ("Allowed && \"Externally-placed field cannot be placed here\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1831, __PRETTY_FUNCTION__))
;
1832 }
1833 } else {
1834 if (!IsUnion && EmptySubobjects) {
1835 // Check if we can place the field at this offset.
1836 while (!EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset)) {
1837 // We couldn't place the field at the offset. Try again at a new offset.
1838 FieldOffset += FieldAlign;
1839 }
1840 }
1841 }
1842
1843 // Place this field at the current location.
1844 FieldOffsets.push_back(Context.toBits(FieldOffset));
1845
1846 if (!UseExternalLayout)
1847 CheckFieldPadding(Context.toBits(FieldOffset), UnpaddedFieldOffset,
1848 Context.toBits(UnpackedFieldOffset),
1849 Context.toBits(UnpackedFieldAlign), FieldPacked, D);
1850
1851 if (InsertExtraPadding) {
1852 CharUnits ASanAlignment = CharUnits::fromQuantity(8);
1853 CharUnits ExtraSizeForAsan = ASanAlignment;
1854 if (FieldSize % ASanAlignment)
1855 ExtraSizeForAsan +=
1856 ASanAlignment - CharUnits::fromQuantity(FieldSize % ASanAlignment);
1857 FieldSize += ExtraSizeForAsan;
1858 }
1859
1860 // Reserve space for this field.
1861 uint64_t FieldSizeInBits = Context.toBits(FieldSize);
1862 if (IsUnion)
1863 setDataSize(std::max(getDataSizeInBits(), FieldSizeInBits));
1864 else
1865 setDataSize(FieldOffset + FieldSize);
1866
1867 // Update the size.
1868 setSize(std::max(getSizeInBits(), getDataSizeInBits()));
1869
1870 // Remember max struct/class alignment.
1871 UnadjustedAlignment = std::max(UnadjustedAlignment, FieldAlign);
1872 UpdateAlignment(FieldAlign, UnpackedFieldAlign);
1873}
1874
1875void ItaniumRecordLayoutBuilder::FinishLayout(const NamedDecl *D) {
1876 // In C++, records cannot be of size 0.
1877 if (Context.getLangOpts().CPlusPlus && getSizeInBits() == 0) {
1878 if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
1879 // Compatibility with gcc requires a class (pod or non-pod)
1880 // which is not empty but of size 0; such as having fields of
1881 // array of zero-length, remains of Size 0
1882 if (RD->isEmpty())
1883 setSize(CharUnits::One());
1884 }
1885 else
1886 setSize(CharUnits::One());
1887 }
1888
1889 // Finally, round the size of the record up to the alignment of the
1890 // record itself.
1891 uint64_t UnpaddedSize = getSizeInBits() - UnfilledBitsInLastUnit;
1892 uint64_t UnpackedSizeInBits =
1893 llvm::alignTo(getSizeInBits(), Context.toBits(UnpackedAlignment));
1894 uint64_t RoundedSize =
1895 llvm::alignTo(getSizeInBits(), Context.toBits(Alignment));
1896
1897 if (UseExternalLayout) {
1898 // If we're inferring alignment, and the external size is smaller than
1899 // our size after we've rounded up to alignment, conservatively set the
1900 // alignment to 1.
1901 if (InferAlignment && External.Size < RoundedSize) {
1902 Alignment = CharUnits::One();
1903 InferAlignment = false;
1904 }
1905 setSize(External.Size);
1906 return;
1907 }
1908
1909 // Set the size to the final size.
1910 setSize(RoundedSize);
1911
1912 unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
1913 if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
1914 // Warn if padding was introduced to the struct/class/union.
1915 if (getSizeInBits() > UnpaddedSize) {
1916 unsigned PadSize = getSizeInBits() - UnpaddedSize;
1917 bool InBits = true;
1918 if (PadSize % CharBitNum == 0) {
1919 PadSize = PadSize / CharBitNum;
1920 InBits = false;
1921 }
1922 Diag(RD->getLocation(), diag::warn_padded_struct_size)
1923 << Context.getTypeDeclType(RD)
1924 << PadSize
1925 << (InBits ? 1 : 0); // (byte|bit)
1926 }
1927
1928 // Warn if we packed it unnecessarily, when the unpacked alignment is not
1929 // greater than the one after packing, the size in bits doesn't change and
1930 // the offset of each field is identical.
1931 if (Packed && UnpackedAlignment <= Alignment &&
1932 UnpackedSizeInBits == getSizeInBits() && !HasPackedField)
1933 Diag(D->getLocation(), diag::warn_unnecessary_packed)
1934 << Context.getTypeDeclType(RD);
1935 }
1936}
1937
1938void ItaniumRecordLayoutBuilder::UpdateAlignment(
1939 CharUnits NewAlignment, CharUnits UnpackedNewAlignment) {
1940 // The alignment is not modified when using 'mac68k' alignment or when
1941 // we have an externally-supplied layout that also provides overall alignment.
1942 if (IsMac68kAlign || (UseExternalLayout && !InferAlignment))
1943 return;
1944
1945 if (NewAlignment > Alignment) {
1946 assert(llvm::isPowerOf2_64(NewAlignment.getQuantity()) &&((llvm::isPowerOf2_64(NewAlignment.getQuantity()) && "Alignment not a power of 2"
) ? static_cast<void> (0) : __assert_fail ("llvm::isPowerOf2_64(NewAlignment.getQuantity()) && \"Alignment not a power of 2\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1947, __PRETTY_FUNCTION__))
1947 "Alignment not a power of 2")((llvm::isPowerOf2_64(NewAlignment.getQuantity()) && "Alignment not a power of 2"
) ? static_cast<void> (0) : __assert_fail ("llvm::isPowerOf2_64(NewAlignment.getQuantity()) && \"Alignment not a power of 2\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1947, __PRETTY_FUNCTION__))
;
1948 Alignment = NewAlignment;
1949 }
1950
1951 if (UnpackedNewAlignment > UnpackedAlignment) {
1952 assert(llvm::isPowerOf2_64(UnpackedNewAlignment.getQuantity()) &&((llvm::isPowerOf2_64(UnpackedNewAlignment.getQuantity()) &&
"Alignment not a power of 2") ? static_cast<void> (0) :
__assert_fail ("llvm::isPowerOf2_64(UnpackedNewAlignment.getQuantity()) && \"Alignment not a power of 2\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1953, __PRETTY_FUNCTION__))
1953 "Alignment not a power of 2")((llvm::isPowerOf2_64(UnpackedNewAlignment.getQuantity()) &&
"Alignment not a power of 2") ? static_cast<void> (0) :
__assert_fail ("llvm::isPowerOf2_64(UnpackedNewAlignment.getQuantity()) && \"Alignment not a power of 2\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1953, __PRETTY_FUNCTION__))
;
1954 UnpackedAlignment = UnpackedNewAlignment;
1955 }
1956}
1957
1958uint64_t
1959ItaniumRecordLayoutBuilder::updateExternalFieldOffset(const FieldDecl *Field,
1960 uint64_t ComputedOffset) {
1961 uint64_t ExternalFieldOffset = External.getExternalFieldOffset(Field);
1962
1963 if (InferAlignment && ExternalFieldOffset < ComputedOffset) {
1964 // The externally-supplied field offset is before the field offset we
1965 // computed. Assume that the structure is packed.
1966 Alignment = CharUnits::One();
1967 InferAlignment = false;
1968 }
1969
1970 // Use the externally-supplied field offset.
1971 return ExternalFieldOffset;
1972}
1973
1974/// Get diagnostic %select index for tag kind for
1975/// field padding diagnostic message.
1976/// WARNING: Indexes apply to particular diagnostics only!
1977///
1978/// \returns diagnostic %select index.
1979static unsigned getPaddingDiagFromTagKind(TagTypeKind Tag) {
1980 switch (Tag) {
1981 case TTK_Struct: return 0;
1982 case TTK_Interface: return 1;
1983 case TTK_Class: return 2;
1984 default: llvm_unreachable("Invalid tag kind for field padding diagnostic!")::llvm::llvm_unreachable_internal("Invalid tag kind for field padding diagnostic!"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1984)
;
1985 }
1986}
1987
1988void ItaniumRecordLayoutBuilder::CheckFieldPadding(
1989 uint64_t Offset, uint64_t UnpaddedOffset, uint64_t UnpackedOffset,
1990 unsigned UnpackedAlign, bool isPacked, const FieldDecl *D) {
1991 // We let objc ivars without warning, objc interfaces generally are not used
1992 // for padding tricks.
1993 if (isa<ObjCIvarDecl>(D))
1994 return;
1995
1996 // Don't warn about structs created without a SourceLocation. This can
1997 // be done by clients of the AST, such as codegen.
1998 if (D->getLocation().isInvalid())
1999 return;
2000
2001 unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
2002
2003 // Warn if padding was introduced to the struct/class.
2004 if (!IsUnion && Offset > UnpaddedOffset) {
2005 unsigned PadSize = Offset - UnpaddedOffset;
2006 bool InBits = true;
2007 if (PadSize % CharBitNum == 0) {
2008 PadSize = PadSize / CharBitNum;
2009 InBits = false;
2010 }
2011 if (D->getIdentifier())
2012 Diag(D->getLocation(), diag::warn_padded_struct_field)
2013 << getPaddingDiagFromTagKind(D->getParent()->getTagKind())
2014 << Context.getTypeDeclType(D->getParent())
2015 << PadSize
2016 << (InBits ? 1 : 0) // (byte|bit)
2017 << D->getIdentifier();
2018 else
2019 Diag(D->getLocation(), diag::warn_padded_struct_anon_field)
2020 << getPaddingDiagFromTagKind(D->getParent()->getTagKind())
2021 << Context.getTypeDeclType(D->getParent())
2022 << PadSize
2023 << (InBits ? 1 : 0); // (byte|bit)
2024 }
2025 if (isPacked && Offset != UnpackedOffset) {
2026 HasPackedField = true;
2027 }
2028}
2029
2030static const CXXMethodDecl *computeKeyFunction(ASTContext &Context,
2031 const CXXRecordDecl *RD) {
2032 // If a class isn't polymorphic it doesn't have a key function.
2033 if (!RD->isPolymorphic())
2034 return nullptr;
2035
2036 // A class that is not externally visible doesn't have a key function. (Or
2037 // at least, there's no point to assigning a key function to such a class;
2038 // this doesn't affect the ABI.)
2039 if (!RD->isExternallyVisible())
2040 return nullptr;
2041
2042 // Template instantiations don't have key functions per Itanium C++ ABI 5.2.6.
2043 // Same behavior as GCC.
2044 TemplateSpecializationKind TSK = RD->getTemplateSpecializationKind();
2045 if (TSK == TSK_ImplicitInstantiation ||
2046 TSK == TSK_ExplicitInstantiationDeclaration ||
2047 TSK == TSK_ExplicitInstantiationDefinition)
2048 return nullptr;
2049
2050 bool allowInlineFunctions =
2051 Context.getTargetInfo().getCXXABI().canKeyFunctionBeInline();
2052
2053 for (const CXXMethodDecl *MD : RD->methods()) {
2054 if (!MD->isVirtual())
2055 continue;
2056
2057 if (MD->isPure())
2058 continue;
2059
2060 // Ignore implicit member functions, they are always marked as inline, but
2061 // they don't have a body until they're defined.
2062 if (MD->isImplicit())
2063 continue;
2064
2065 if (MD->isInlineSpecified())
2066 continue;
2067
2068 if (MD->hasInlineBody())
2069 continue;
2070
2071 // Ignore inline deleted or defaulted functions.
2072 if (!MD->isUserProvided())
2073 continue;
2074
2075 // In certain ABIs, ignore functions with out-of-line inline definitions.
2076 if (!allowInlineFunctions) {
2077 const FunctionDecl *Def;
2078 if (MD->hasBody(Def) && Def->isInlineSpecified())
2079 continue;
2080 }
2081
2082 if (Context.getLangOpts().CUDA) {
2083 // While compiler may see key method in this TU, during CUDA
2084 // compilation we should ignore methods that are not accessible
2085 // on this side of compilation.
2086 if (Context.getLangOpts().CUDAIsDevice) {
2087 // In device mode ignore methods without __device__ attribute.
2088 if (!MD->hasAttr<CUDADeviceAttr>())
2089 continue;
2090 } else {
2091 // In host mode ignore __device__-only methods.
2092 if (!MD->hasAttr<CUDAHostAttr>() && MD->hasAttr<CUDADeviceAttr>())
2093 continue;
2094 }
2095 }
2096
2097 // If the key function is dllimport but the class isn't, then the class has
2098 // no key function. The DLL that exports the key function won't export the
2099 // vtable in this case.
2100 if (MD->hasAttr<DLLImportAttr>() && !RD->hasAttr<DLLImportAttr>())
2101 return nullptr;
2102
2103 // We found it.
2104 return MD;
2105 }
2106
2107 return nullptr;
2108}
2109
2110DiagnosticBuilder ItaniumRecordLayoutBuilder::Diag(SourceLocation Loc,
2111 unsigned DiagID) {
2112 return Context.getDiagnostics().Report(Loc, DiagID);
2113}
2114
2115/// Does the target C++ ABI require us to skip over the tail-padding
2116/// of the given class (considering it as a base class) when allocating
2117/// objects?
2118static bool mustSkipTailPadding(TargetCXXABI ABI, const CXXRecordDecl *RD) {
2119 switch (ABI.getTailPaddingUseRules()) {
2120 case TargetCXXABI::AlwaysUseTailPadding:
2121 return false;
2122
2123 case TargetCXXABI::UseTailPaddingUnlessPOD03:
2124 // FIXME: To the extent that this is meant to cover the Itanium ABI
2125 // rules, we should implement the restrictions about over-sized
2126 // bitfields:
2127 //
2128 // http://itanium-cxx-abi.github.io/cxx-abi/abi.html#POD :
2129 // In general, a type is considered a POD for the purposes of
2130 // layout if it is a POD type (in the sense of ISO C++
2131 // [basic.types]). However, a POD-struct or POD-union (in the
2132 // sense of ISO C++ [class]) with a bitfield member whose
2133 // declared width is wider than the declared type of the
2134 // bitfield is not a POD for the purpose of layout. Similarly,
2135 // an array type is not a POD for the purpose of layout if the
2136 // element type of the array is not a POD for the purpose of
2137 // layout.
2138 //
2139 // Where references to the ISO C++ are made in this paragraph,
2140 // the Technical Corrigendum 1 version of the standard is
2141 // intended.
2142 return RD->isPOD();
2143
2144 case TargetCXXABI::UseTailPaddingUnlessPOD11:
2145 // This is equivalent to RD->getTypeForDecl().isCXX11PODType(),
2146 // but with a lot of abstraction penalty stripped off. This does
2147 // assume that these properties are set correctly even in C++98
2148 // mode; fortunately, that is true because we want to assign
2149 // consistently semantics to the type-traits intrinsics (or at
2150 // least as many of them as possible).
2151 return RD->isTrivial() && RD->isCXX11StandardLayout();
2152 }
2153
2154 llvm_unreachable("bad tail-padding use kind")::llvm::llvm_unreachable_internal("bad tail-padding use kind"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2154)
;
2155}
2156
2157static bool isMsLayout(const ASTContext &Context) {
2158 return Context.getTargetInfo().getCXXABI().isMicrosoft();
2159}
2160
2161// This section contains an implementation of struct layout that is, up to the
2162// included tests, compatible with cl.exe (2013). The layout produced is
2163// significantly different than those produced by the Itanium ABI. Here we note
2164// the most important differences.
2165//
2166// * The alignment of bitfields in unions is ignored when computing the
2167// alignment of the union.
2168// * The existence of zero-width bitfield that occurs after anything other than
2169// a non-zero length bitfield is ignored.
2170// * There is no explicit primary base for the purposes of layout. All bases
2171// with vfptrs are laid out first, followed by all bases without vfptrs.
2172// * The Itanium equivalent vtable pointers are split into a vfptr (virtual
2173// function pointer) and a vbptr (virtual base pointer). They can each be
2174// shared with a, non-virtual bases. These bases need not be the same. vfptrs
2175// always occur at offset 0. vbptrs can occur at an arbitrary offset and are
2176// placed after the lexicographically last non-virtual base. This placement
2177// is always before fields but can be in the middle of the non-virtual bases
2178// due to the two-pass layout scheme for non-virtual-bases.
2179// * Virtual bases sometimes require a 'vtordisp' field that is laid out before
2180// the virtual base and is used in conjunction with virtual overrides during
2181// construction and destruction. This is always a 4 byte value and is used as
2182// an alternative to constructor vtables.
2183// * vtordisps are allocated in a block of memory with size and alignment equal
2184// to the alignment of the completed structure (before applying __declspec(
2185// align())). The vtordisp always occur at the end of the allocation block,
2186// immediately prior to the virtual base.
2187// * vfptrs are injected after all bases and fields have been laid out. In
2188// order to guarantee proper alignment of all fields, the vfptr injection
2189// pushes all bases and fields back by the alignment imposed by those bases
2190// and fields. This can potentially add a significant amount of padding.
2191// vfptrs are always injected at offset 0.
2192// * vbptrs are injected after all bases and fields have been laid out. In
2193// order to guarantee proper alignment of all fields, the vfptr injection
2194// pushes all bases and fields back by the alignment imposed by those bases
2195// and fields. This can potentially add a significant amount of padding.
2196// vbptrs are injected immediately after the last non-virtual base as
2197// lexicographically ordered in the code. If this site isn't pointer aligned
2198// the vbptr is placed at the next properly aligned location. Enough padding
2199// is added to guarantee a fit.
2200// * The last zero sized non-virtual base can be placed at the end of the
2201// struct (potentially aliasing another object), or may alias with the first
2202// field, even if they are of the same type.
2203// * The last zero size virtual base may be placed at the end of the struct
2204// potentially aliasing another object.
2205// * The ABI attempts to avoid aliasing of zero sized bases by adding padding
2206// between bases or vbases with specific properties. The criteria for
2207// additional padding between two bases is that the first base is zero sized
2208// or ends with a zero sized subobject and the second base is zero sized or
2209// trails with a zero sized base or field (sharing of vfptrs can reorder the
2210// layout of the so the leading base is not always the first one declared).
2211// This rule does take into account fields that are not records, so padding
2212// will occur even if the last field is, e.g. an int. The padding added for
2213// bases is 1 byte. The padding added between vbases depends on the alignment
2214// of the object but is at least 4 bytes (in both 32 and 64 bit modes).
2215// * There is no concept of non-virtual alignment, non-virtual alignment and
2216// alignment are always identical.
2217// * There is a distinction between alignment and required alignment.
2218// __declspec(align) changes the required alignment of a struct. This
2219// alignment is _always_ obeyed, even in the presence of #pragma pack. A
2220// record inherits required alignment from all of its fields and bases.
2221// * __declspec(align) on bitfields has the effect of changing the bitfield's
2222// alignment instead of its required alignment. This is the only known way
2223// to make the alignment of a struct bigger than 8. Interestingly enough
2224// this alignment is also immune to the effects of #pragma pack and can be
2225// used to create structures with large alignment under #pragma pack.
2226// However, because it does not impact required alignment, such a structure,
2227// when used as a field or base, will not be aligned if #pragma pack is
2228// still active at the time of use.
2229//
2230// Known incompatibilities:
2231// * all: #pragma pack between fields in a record
2232// * 2010 and back: If the last field in a record is a bitfield, every object
2233// laid out after the record will have extra padding inserted before it. The
2234// extra padding will have size equal to the size of the storage class of the
2235// bitfield. 0 sized bitfields don't exhibit this behavior and the extra
2236// padding can be avoided by adding a 0 sized bitfield after the non-zero-
2237// sized bitfield.
2238// * 2012 and back: In 64-bit mode, if the alignment of a record is 16 or
2239// greater due to __declspec(align()) then a second layout phase occurs after
2240// The locations of the vf and vb pointers are known. This layout phase
2241// suffers from the "last field is a bitfield" bug in 2010 and results in
2242// _every_ field getting padding put in front of it, potentially including the
2243// vfptr, leaving the vfprt at a non-zero location which results in a fault if
2244// anything tries to read the vftbl. The second layout phase also treats
2245// bitfields as separate entities and gives them each storage rather than
2246// packing them. Additionally, because this phase appears to perform a
2247// (an unstable) sort on the members before laying them out and because merged
2248// bitfields have the same address, the bitfields end up in whatever order
2249// the sort left them in, a behavior we could never hope to replicate.
2250
2251namespace {
2252struct MicrosoftRecordLayoutBuilder {
2253 struct ElementInfo {
2254 CharUnits Size;
2255 CharUnits Alignment;
2256 };
2257 typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
2258 MicrosoftRecordLayoutBuilder(const ASTContext &Context) : Context(Context) {}
2259private:
2260 MicrosoftRecordLayoutBuilder(const MicrosoftRecordLayoutBuilder &) = delete;
2261 void operator=(const MicrosoftRecordLayoutBuilder &) = delete;
2262public:
2263 void layout(const RecordDecl *RD);
2264 void cxxLayout(const CXXRecordDecl *RD);
2265 /// Initializes size and alignment and honors some flags.
2266 void initializeLayout(const RecordDecl *RD);
2267 /// Initialized C++ layout, compute alignment and virtual alignment and
2268 /// existence of vfptrs and vbptrs. Alignment is needed before the vfptr is
2269 /// laid out.
2270 void initializeCXXLayout(const CXXRecordDecl *RD);
2271 void layoutNonVirtualBases(const CXXRecordDecl *RD);
2272 void layoutNonVirtualBase(const CXXRecordDecl *RD,
2273 const CXXRecordDecl *BaseDecl,
2274 const ASTRecordLayout &BaseLayout,
2275 const ASTRecordLayout *&PreviousBaseLayout);
2276 void injectVFPtr(const CXXRecordDecl *RD);
2277 void injectVBPtr(const CXXRecordDecl *RD);
2278 /// Lays out the fields of the record. Also rounds size up to
2279 /// alignment.
2280 void layoutFields(const RecordDecl *RD);
2281 void layoutField(const FieldDecl *FD);
2282 void layoutBitField(const FieldDecl *FD);
2283 /// Lays out a single zero-width bit-field in the record and handles
2284 /// special cases associated with zero-width bit-fields.
2285 void layoutZeroWidthBitField(const FieldDecl *FD);
2286 void layoutVirtualBases(const CXXRecordDecl *RD);
2287 void finalizeLayout(const RecordDecl *RD);
2288 /// Gets the size and alignment of a base taking pragma pack and
2289 /// __declspec(align) into account.
2290 ElementInfo getAdjustedElementInfo(const ASTRecordLayout &Layout);
2291 /// Gets the size and alignment of a field taking pragma pack and
2292 /// __declspec(align) into account. It also updates RequiredAlignment as a
2293 /// side effect because it is most convenient to do so here.
2294 ElementInfo getAdjustedElementInfo(const FieldDecl *FD);
2295 /// Places a field at an offset in CharUnits.
2296 void placeFieldAtOffset(CharUnits FieldOffset) {
2297 FieldOffsets.push_back(Context.toBits(FieldOffset));
2298 }
2299 /// Places a bitfield at a bit offset.
2300 void placeFieldAtBitOffset(uint64_t FieldOffset) {
2301 FieldOffsets.push_back(FieldOffset);
2302 }
2303 /// Compute the set of virtual bases for which vtordisps are required.
2304 void computeVtorDispSet(
2305 llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtorDispSet,
2306 const CXXRecordDecl *RD) const;
2307 const ASTContext &Context;
2308 /// The size of the record being laid out.
2309 CharUnits Size;
2310 /// The non-virtual size of the record layout.
2311 CharUnits NonVirtualSize;
2312 /// The data size of the record layout.
2313 CharUnits DataSize;
2314 /// The current alignment of the record layout.
2315 CharUnits Alignment;
2316 /// The maximum allowed field alignment. This is set by #pragma pack.
2317 CharUnits MaxFieldAlignment;
2318 /// The alignment that this record must obey. This is imposed by
2319 /// __declspec(align()) on the record itself or one of its fields or bases.
2320 CharUnits RequiredAlignment;
2321 /// The size of the allocation of the currently active bitfield.
2322 /// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield
2323 /// is true.
2324 CharUnits CurrentBitfieldSize;
2325 /// Offset to the virtual base table pointer (if one exists).
2326 CharUnits VBPtrOffset;
2327 /// Minimum record size possible.
2328 CharUnits MinEmptyStructSize;
2329 /// The size and alignment info of a pointer.
2330 ElementInfo PointerInfo;
2331 /// The primary base class (if one exists).
2332 const CXXRecordDecl *PrimaryBase;
2333 /// The class we share our vb-pointer with.
2334 const CXXRecordDecl *SharedVBPtrBase;
2335 /// The collection of field offsets.
2336 SmallVector<uint64_t, 16> FieldOffsets;
2337 /// Base classes and their offsets in the record.
2338 BaseOffsetsMapTy Bases;
2339 /// virtual base classes and their offsets in the record.
2340 ASTRecordLayout::VBaseOffsetsMapTy VBases;
2341 /// The number of remaining bits in our last bitfield allocation.
2342 /// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield is
2343 /// true.
2344 unsigned RemainingBitsInField;
2345 bool IsUnion : 1;
2346 /// True if the last field laid out was a bitfield and was not 0
2347 /// width.
2348 bool LastFieldIsNonZeroWidthBitfield : 1;
2349 /// True if the class has its own vftable pointer.
2350 bool HasOwnVFPtr : 1;
2351 /// True if the class has a vbtable pointer.
2352 bool HasVBPtr : 1;
2353 /// True if the last sub-object within the type is zero sized or the
2354 /// object itself is zero sized. This *does not* count members that are not
2355 /// records. Only used for MS-ABI.
2356 bool EndsWithZeroSizedObject : 1;
2357 /// True if this class is zero sized or first base is zero sized or
2358 /// has this property. Only used for MS-ABI.
2359 bool LeadsWithZeroSizedBase : 1;
2360
2361 /// True if the external AST source provided a layout for this record.
2362 bool UseExternalLayout : 1;
2363
2364 /// The layout provided by the external AST source. Only active if
2365 /// UseExternalLayout is true.
2366 ExternalLayout External;
2367};
2368} // namespace
2369
2370MicrosoftRecordLayoutBuilder::ElementInfo
2371MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
2372 const ASTRecordLayout &Layout) {
2373 ElementInfo Info;
2374 Info.Alignment = Layout.getAlignment();
2375 // Respect pragma pack.
2376 if (!MaxFieldAlignment.isZero())
2377 Info.Alignment = std::min(Info.Alignment, MaxFieldAlignment);
2378 // Track zero-sized subobjects here where it's already available.
2379 EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
2380 // Respect required alignment, this is necessary because we may have adjusted
2381 // the alignment in the case of pragam pack. Note that the required alignment
2382 // doesn't actually apply to the struct alignment at this point.
2383 Alignment = std::max(Alignment, Info.Alignment);
2384 RequiredAlignment = std::max(RequiredAlignment, Layout.getRequiredAlignment());
2385 Info.Alignment = std::max(Info.Alignment, Layout.getRequiredAlignment());
2386 Info.Size = Layout.getNonVirtualSize();
2387 return Info;
2388}
2389
2390MicrosoftRecordLayoutBuilder::ElementInfo
2391MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
2392 const FieldDecl *FD) {
2393 // Get the alignment of the field type's natural alignment, ignore any
2394 // alignment attributes.
2395 ElementInfo Info;
2396 std::tie(Info.Size, Info.Alignment) =
2397 Context.getTypeInfoInChars(FD->getType()->getUnqualifiedDesugaredType());
2398 // Respect align attributes on the field.
2399 CharUnits FieldRequiredAlignment =
2400 Context.toCharUnitsFromBits(FD->getMaxAlignment());
2401 // Respect align attributes on the type.
2402 if (Context.isAlignmentRequired(FD->getType()))
2403 FieldRequiredAlignment = std::max(
2404 Context.getTypeAlignInChars(FD->getType()), FieldRequiredAlignment);
2405 // Respect attributes applied to subobjects of the field.
2406 if (FD->isBitField())
2407 // For some reason __declspec align impacts alignment rather than required
2408 // alignment when it is applied to bitfields.
2409 Info.Alignment = std::max(Info.Alignment, FieldRequiredAlignment);
2410 else {
2411 if (auto RT =
2412 FD->getType()->getBaseElementTypeUnsafe()->getAs<RecordType>()) {
2413 auto const &Layout = Context.getASTRecordLayout(RT->getDecl());
2414 EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
2415 FieldRequiredAlignment = std::max(FieldRequiredAlignment,
2416 Layout.getRequiredAlignment());
2417 }
2418 // Capture required alignment as a side-effect.
2419 RequiredAlignment = std::max(RequiredAlignment, FieldRequiredAlignment);
2420 }
2421 // Respect pragma pack, attribute pack and declspec align
2422 if (!MaxFieldAlignment.isZero())
2423 Info.Alignment = std::min(Info.Alignment, MaxFieldAlignment);
2424 if (FD->hasAttr<PackedAttr>())
2425 Info.Alignment = CharUnits::One();
2426 Info.Alignment = std::max(Info.Alignment, FieldRequiredAlignment);
2427 return Info;
2428}
2429
2430void MicrosoftRecordLayoutBuilder::layout(const RecordDecl *RD) {
2431 // For C record layout, zero-sized records always have size 4.
2432 MinEmptyStructSize = CharUnits::fromQuantity(4);
2433 initializeLayout(RD);
2434 layoutFields(RD);
2435 DataSize = Size = Size.alignTo(Alignment);
2436 RequiredAlignment = std::max(
2437 RequiredAlignment, Context.toCharUnitsFromBits(RD->getMaxAlignment()));
2438 finalizeLayout(RD);
2439}
2440
2441void MicrosoftRecordLayoutBuilder::cxxLayout(const CXXRecordDecl *RD) {
2442 // The C++ standard says that empty structs have size 1.
2443 MinEmptyStructSize = CharUnits::One();
2444 initializeLayout(RD);
2445 initializeCXXLayout(RD);
2446 layoutNonVirtualBases(RD);
2447 layoutFields(RD);
2448 injectVBPtr(RD);
2449 injectVFPtr(RD);
2450 if (HasOwnVFPtr || (HasVBPtr && !SharedVBPtrBase))
2451 Alignment = std::max(Alignment, PointerInfo.Alignment);
2452 auto RoundingAlignment = Alignment;
2453 if (!MaxFieldAlignment.isZero())
2454 RoundingAlignment = std::min(RoundingAlignment, MaxFieldAlignment);
2455 if (!UseExternalLayout)
2456 Size = Size.alignTo(RoundingAlignment);
2457 NonVirtualSize = Size;
2458 RequiredAlignment = std::max(
2459 RequiredAlignment, Context.toCharUnitsFromBits(RD->getMaxAlignment()));
2460 layoutVirtualBases(RD);
2461 finalizeLayout(RD);
2462}
2463
2464void MicrosoftRecordLayoutBuilder::initializeLayout(const RecordDecl *RD) {
2465 IsUnion = RD->isUnion();
2466 Size = CharUnits::Zero();
2467 Alignment = CharUnits::One();
2468 // In 64-bit mode we always perform an alignment step after laying out vbases.
2469 // In 32-bit mode we do not. The check to see if we need to perform alignment
2470 // checks the RequiredAlignment field and performs alignment if it isn't 0.
2471 RequiredAlignment = Context.getTargetInfo().getTriple().isArch64Bit()
2472 ? CharUnits::One()
2473 : CharUnits::Zero();
2474 // Compute the maximum field alignment.
2475 MaxFieldAlignment = CharUnits::Zero();
2476 // Honor the default struct packing maximum alignment flag.
2477 if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct)
2478 MaxFieldAlignment = CharUnits::fromQuantity(DefaultMaxFieldAlignment);
2479 // Honor the packing attribute. The MS-ABI ignores pragma pack if its larger
2480 // than the pointer size.
2481 if (const MaxFieldAlignmentAttr *MFAA = RD->getAttr<MaxFieldAlignmentAttr>()){
2482 unsigned PackedAlignment = MFAA->getAlignment();
2483 if (PackedAlignment <= Context.getTargetInfo().getPointerWidth(0))
2484 MaxFieldAlignment = Context.toCharUnitsFromBits(PackedAlignment);
2485 }
2486 // Packed attribute forces max field alignment to be 1.
2487 if (RD->hasAttr<PackedAttr>())
2488 MaxFieldAlignment = CharUnits::One();
2489
2490 // Try to respect the external layout if present.
2491 UseExternalLayout = false;
2492 if (ExternalASTSource *Source = Context.getExternalSource())
2493 UseExternalLayout = Source->layoutRecordType(
2494 RD, External.Size, External.Align, External.FieldOffsets,
2495 External.BaseOffsets, External.VirtualBaseOffsets);
2496}
2497
2498void
2499MicrosoftRecordLayoutBuilder::initializeCXXLayout(const CXXRecordDecl *RD) {
2500 EndsWithZeroSizedObject = false;
2501 LeadsWithZeroSizedBase = false;
2502 HasOwnVFPtr = false;
2503 HasVBPtr = false;
2504 PrimaryBase = nullptr;
2505 SharedVBPtrBase = nullptr;
2506 // Calculate pointer size and alignment. These are used for vfptr and vbprt
2507 // injection.
2508 PointerInfo.Size =
2509 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
2510 PointerInfo.Alignment =
2511 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(0));
2512 // Respect pragma pack.
2513 if (!MaxFieldAlignment.isZero())
2514 PointerInfo.Alignment = std::min(PointerInfo.Alignment, MaxFieldAlignment);
2515}
2516
2517void
2518MicrosoftRecordLayoutBuilder::layoutNonVirtualBases(const CXXRecordDecl *RD) {
2519 // The MS-ABI lays out all bases that contain leading vfptrs before it lays
2520 // out any bases that do not contain vfptrs. We implement this as two passes
2521 // over the bases. This approach guarantees that the primary base is laid out
2522 // first. We use these passes to calculate some additional aggregated
2523 // information about the bases, such as required alignment and the presence of
2524 // zero sized members.
2525 const ASTRecordLayout *PreviousBaseLayout = nullptr;
2526 // Iterate through the bases and lay out the non-virtual ones.
2527 for (const CXXBaseSpecifier &Base : RD->bases()) {
2528 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2529 const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2530 // Mark and skip virtual bases.
2531 if (Base.isVirtual()) {
2532 HasVBPtr = true;
2533 continue;
2534 }
2535 // Check for a base to share a VBPtr with.
2536 if (!SharedVBPtrBase && BaseLayout.hasVBPtr()) {
2537 SharedVBPtrBase = BaseDecl;
2538 HasVBPtr = true;
2539 }
2540 // Only lay out bases with extendable VFPtrs on the first pass.
2541 if (!BaseLayout.hasExtendableVFPtr())
2542 continue;
2543 // If we don't have a primary base, this one qualifies.
2544 if (!PrimaryBase) {
2545 PrimaryBase = BaseDecl;
2546 LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
2547 }
2548 // Lay out the base.
2549 layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
2550 }
2551 // Figure out if we need a fresh VFPtr for this class.
2552 if (!PrimaryBase && RD->isDynamicClass())
2553 for (CXXRecordDecl::method_iterator i = RD->method_begin(),
2554 e = RD->method_end();
2555 !HasOwnVFPtr && i != e; ++i)
2556 HasOwnVFPtr = i->isVirtual() && i->size_overridden_methods() == 0;
2557 // If we don't have a primary base then we have a leading object that could
2558 // itself lead with a zero-sized object, something we track.
2559 bool CheckLeadingLayout = !PrimaryBase;
2560 // Iterate through the bases and lay out the non-virtual ones.
2561 for (const CXXBaseSpecifier &Base : RD->bases()) {
2562 if (Base.isVirtual())
2563 continue;
2564 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2565 const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2566 // Only lay out bases without extendable VFPtrs on the second pass.
2567 if (BaseLayout.hasExtendableVFPtr()) {
2568 VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
2569 continue;
2570 }
2571 // If this is the first layout, check to see if it leads with a zero sized
2572 // object. If it does, so do we.
2573 if (CheckLeadingLayout) {
2574 CheckLeadingLayout = false;
2575 LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
2576 }
2577 // Lay out the base.
2578 layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
2579 VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
2580 }
2581 // Set our VBPtroffset if we know it at this point.
2582 if (!HasVBPtr)
2583 VBPtrOffset = CharUnits::fromQuantity(-1);
2584 else if (SharedVBPtrBase) {
2585 const ASTRecordLayout &Layout = Context.getASTRecordLayout(SharedVBPtrBase);
2586 VBPtrOffset = Bases[SharedVBPtrBase] + Layout.getVBPtrOffset();
2587 }
2588}
2589
2590static bool recordUsesEBO(const RecordDecl *RD) {
2591 if (!isa<CXXRecordDecl>(RD))
2592 return false;
2593 if (RD->hasAttr<EmptyBasesAttr>())
2594 return true;
2595 if (auto *LVA = RD->getAttr<LayoutVersionAttr>())
2596 // TODO: Double check with the next version of MSVC.
2597 if (LVA->getVersion() <= LangOptions::MSVC2015)
2598 return false;
2599 // TODO: Some later version of MSVC will change the default behavior of the
2600 // compiler to enable EBO by default. When this happens, we will need an
2601 // additional isCompatibleWithMSVC check.
2602 return false;
2603}
2604
2605void MicrosoftRecordLayoutBuilder::layoutNonVirtualBase(
2606 const CXXRecordDecl *RD,
2607 const CXXRecordDecl *BaseDecl,
2608 const ASTRecordLayout &BaseLayout,
2609 const ASTRecordLayout *&PreviousBaseLayout) {
2610 // Insert padding between two bases if the left first one is zero sized or
2611 // contains a zero sized subobject and the right is zero sized or one leads
2612 // with a zero sized base.
2613 bool MDCUsesEBO = recordUsesEBO(RD);
2614 if (PreviousBaseLayout && PreviousBaseLayout->endsWithZeroSizedObject() &&
2615 BaseLayout.leadsWithZeroSizedBase() && !MDCUsesEBO)
2616 Size++;
2617 ElementInfo Info = getAdjustedElementInfo(BaseLayout);
2618 CharUnits BaseOffset;
2619
2620 // Respect the external AST source base offset, if present.
2621 bool FoundBase = false;
2622 if (UseExternalLayout) {
2623 FoundBase = External.getExternalNVBaseOffset(BaseDecl, BaseOffset);
2624 if (FoundBase) {
2625 assert(BaseOffset >= Size && "base offset already allocated")((BaseOffset >= Size && "base offset already allocated"
) ? static_cast<void> (0) : __assert_fail ("BaseOffset >= Size && \"base offset already allocated\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2625, __PRETTY_FUNCTION__))
;
2626 Size = BaseOffset;
2627 }
2628 }
2629
2630 if (!FoundBase) {
2631 if (MDCUsesEBO && BaseDecl->isEmpty()) {
2632 assert(BaseLayout.getNonVirtualSize() == CharUnits::Zero())((BaseLayout.getNonVirtualSize() == CharUnits::Zero()) ? static_cast
<void> (0) : __assert_fail ("BaseLayout.getNonVirtualSize() == CharUnits::Zero()"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2632, __PRETTY_FUNCTION__))
;
2633 BaseOffset = CharUnits::Zero();
2634 } else {
2635 // Otherwise, lay the base out at the end of the MDC.
2636 BaseOffset = Size = Size.alignTo(Info.Alignment);
2637 }
2638 }
2639 Bases.insert(std::make_pair(BaseDecl, BaseOffset));
2640 Size += BaseLayout.getNonVirtualSize();
2641 PreviousBaseLayout = &BaseLayout;
2642}
2643
2644void MicrosoftRecordLayoutBuilder::layoutFields(const RecordDecl *RD) {
2645 LastFieldIsNonZeroWidthBitfield = false;
2646 for (const FieldDecl *Field : RD->fields())
2647 layoutField(Field);
2648}
2649
2650void MicrosoftRecordLayoutBuilder::layoutField(const FieldDecl *FD) {
2651 if (FD->isBitField()) {
2652 layoutBitField(FD);
2653 return;
2654 }
2655 LastFieldIsNonZeroWidthBitfield = false;
2656 ElementInfo Info = getAdjustedElementInfo(FD);
2657 Alignment = std::max(Alignment, Info.Alignment);
2658 CharUnits FieldOffset;
2659 if (UseExternalLayout)
2660 FieldOffset =
2661 Context.toCharUnitsFromBits(External.getExternalFieldOffset(FD));
2662 else if (IsUnion)
2663 FieldOffset = CharUnits::Zero();
2664 else
2665 FieldOffset = Size.alignTo(Info.Alignment);
2666 placeFieldAtOffset(FieldOffset);
2667 Size = std::max(Size, FieldOffset + Info.Size);
2668}
2669
2670void MicrosoftRecordLayoutBuilder::layoutBitField(const FieldDecl *FD) {
2671 unsigned Width = FD->getBitWidthValue(Context);
2672 if (Width == 0) {
2673 layoutZeroWidthBitField(FD);
2674 return;
2675 }
2676 ElementInfo Info = getAdjustedElementInfo(FD);
2677 // Clamp the bitfield to a containable size for the sake of being able
2678 // to lay them out. Sema will throw an error.
2679 if (Width > Context.toBits(Info.Size))
2680 Width = Context.toBits(Info.Size);
2681 // Check to see if this bitfield fits into an existing allocation. Note:
2682 // MSVC refuses to pack bitfields of formal types with different sizes
2683 // into the same allocation.
2684 if (!UseExternalLayout && !IsUnion && LastFieldIsNonZeroWidthBitfield &&
2685 CurrentBitfieldSize == Info.Size && Width <= RemainingBitsInField) {
2686 placeFieldAtBitOffset(Context.toBits(Size) - RemainingBitsInField);
2687 RemainingBitsInField -= Width;
2688 return;
2689 }
2690 LastFieldIsNonZeroWidthBitfield = true;
2691 CurrentBitfieldSize = Info.Size;
2692 if (UseExternalLayout) {
2693 auto FieldBitOffset = External.getExternalFieldOffset(FD);
2694 placeFieldAtBitOffset(FieldBitOffset);
2695 auto NewSize = Context.toCharUnitsFromBits(
2696 llvm::alignTo(FieldBitOffset + Width, Context.getCharWidth()));
2697 Size = std::max(Size, NewSize);
2698 Alignment = std::max(Alignment, Info.Alignment);
2699 } else if (IsUnion) {
2700 placeFieldAtOffset(CharUnits::Zero());
2701 Size = std::max(Size, Info.Size);
2702 // TODO: Add a Sema warning that MS ignores bitfield alignment in unions.
2703 } else {
2704 // Allocate a new block of memory and place the bitfield in it.
2705 CharUnits FieldOffset = Size.alignTo(Info.Alignment);
2706 placeFieldAtOffset(FieldOffset);
2707 Size = FieldOffset + Info.Size;
2708 Alignment = std::max(Alignment, Info.Alignment);
2709 RemainingBitsInField = Context.toBits(Info.Size) - Width;
2710 }
2711}
2712
2713void
2714MicrosoftRecordLayoutBuilder::layoutZeroWidthBitField(const FieldDecl *FD) {
2715 // Zero-width bitfields are ignored unless they follow a non-zero-width
2716 // bitfield.
2717 if (!LastFieldIsNonZeroWidthBitfield) {
2718 placeFieldAtOffset(IsUnion ? CharUnits::Zero() : Size);
2719 // TODO: Add a Sema warning that MS ignores alignment for zero
2720 // sized bitfields that occur after zero-size bitfields or non-bitfields.
2721 return;
2722 }
2723 LastFieldIsNonZeroWidthBitfield = false;
2724 ElementInfo Info = getAdjustedElementInfo(FD);
2725 if (IsUnion) {
2726 placeFieldAtOffset(CharUnits::Zero());
2727 Size = std::max(Size, Info.Size);
2728 // TODO: Add a Sema warning that MS ignores bitfield alignment in unions.
2729 } else {
2730 // Round up the current record size to the field's alignment boundary.
2731 CharUnits FieldOffset = Size.alignTo(Info.Alignment);
2732 placeFieldAtOffset(FieldOffset);
2733 Size = FieldOffset;
2734 Alignment = std::max(Alignment, Info.Alignment);
2735 }
2736}
2737
2738void MicrosoftRecordLayoutBuilder::injectVBPtr(const CXXRecordDecl *RD) {
2739 if (!HasVBPtr || SharedVBPtrBase)
2740 return;
2741 // Inject the VBPointer at the injection site.
2742 CharUnits InjectionSite = VBPtrOffset;
2743 // But before we do, make sure it's properly aligned.
2744 VBPtrOffset = VBPtrOffset.alignTo(PointerInfo.Alignment);
2745 // Shift everything after the vbptr down, unless we're using an external
2746 // layout.
2747 if (UseExternalLayout)
2748 return;
2749 // Determine where the first field should be laid out after the vbptr.
2750 CharUnits FieldStart = VBPtrOffset + PointerInfo.Size;
2751 // Make sure that the amount we push the fields back by is a multiple of the
2752 // alignment.
2753 CharUnits Offset = (FieldStart - InjectionSite)
2754 .alignTo(std::max(RequiredAlignment, Alignment));
2755 Size += Offset;
2756 for (uint64_t &FieldOffset : FieldOffsets)
2757 FieldOffset += Context.toBits(Offset);
2758 for (BaseOffsetsMapTy::value_type &Base : Bases)
2759 if (Base.second >= InjectionSite)
2760 Base.second += Offset;
2761}
2762
2763void MicrosoftRecordLayoutBuilder::injectVFPtr(const CXXRecordDecl *RD) {
2764 if (!HasOwnVFPtr)
2765 return;
2766 // Make sure that the amount we push the struct back by is a multiple of the
2767 // alignment.
2768 CharUnits Offset =
2769 PointerInfo.Size.alignTo(std::max(RequiredAlignment, Alignment));
2770 // Push back the vbptr, but increase the size of the object and push back
2771 // regular fields by the offset only if not using external record layout.
2772 if (HasVBPtr)
2773 VBPtrOffset += Offset;
2774
2775 if (UseExternalLayout)
2776 return;
2777
2778 Size += Offset;
2779
2780 // If we're using an external layout, the fields offsets have already
2781 // accounted for this adjustment.
2782 for (uint64_t &FieldOffset : FieldOffsets)
2783 FieldOffset += Context.toBits(Offset);
2784 for (BaseOffsetsMapTy::value_type &Base : Bases)
2785 Base.second += Offset;
2786}
2787
2788void MicrosoftRecordLayoutBuilder::layoutVirtualBases(const CXXRecordDecl *RD) {
2789 if (!HasVBPtr)
2790 return;
2791 // Vtordisps are always 4 bytes (even in 64-bit mode)
2792 CharUnits VtorDispSize = CharUnits::fromQuantity(4);
2793 CharUnits VtorDispAlignment = VtorDispSize;
2794 // vtordisps respect pragma pack.
2795 if (!MaxFieldAlignment.isZero())
2796 VtorDispAlignment = std::min(VtorDispAlignment, MaxFieldAlignment);
2797 // The alignment of the vtordisp is at least the required alignment of the
2798 // entire record. This requirement may be present to support vtordisp
2799 // injection.
2800 for (const CXXBaseSpecifier &VBase : RD->vbases()) {
2801 const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
2802 const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2803 RequiredAlignment =
2804 std::max(RequiredAlignment, BaseLayout.getRequiredAlignment());
2805 }
2806 VtorDispAlignment = std::max(VtorDispAlignment, RequiredAlignment);
2807 // Compute the vtordisp set.
2808 llvm::SmallPtrSet<const CXXRecordDecl *, 2> HasVtorDispSet;
2809 computeVtorDispSet(HasVtorDispSet, RD);
2810 // Iterate through the virtual bases and lay them out.
2811 const ASTRecordLayout *PreviousBaseLayout = nullptr;
2812 for (const CXXBaseSpecifier &VBase : RD->vbases()) {
2813 const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
2814 const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2815 bool HasVtordisp = HasVtorDispSet.count(BaseDecl) > 0;
2816 // Insert padding between two bases if the left first one is zero sized or
2817 // contains a zero sized subobject and the right is zero sized or one leads
2818 // with a zero sized base. The padding between virtual bases is 4
2819 // bytes (in both 32 and 64 bits modes) and always involves rounding up to
2820 // the required alignment, we don't know why.
2821 if ((PreviousBaseLayout && PreviousBaseLayout->endsWithZeroSizedObject() &&
2822 BaseLayout.leadsWithZeroSizedBase() && !recordUsesEBO(RD)) ||
2823 HasVtordisp) {
2824 Size = Size.alignTo(VtorDispAlignment) + VtorDispSize;
2825 Alignment = std::max(VtorDispAlignment, Alignment);
2826 }
2827 // Insert the virtual base.
2828 ElementInfo Info = getAdjustedElementInfo(BaseLayout);
2829 CharUnits BaseOffset;
2830
2831 // Respect the external AST source base offset, if present.
2832 if (UseExternalLayout) {
2833 if (!External.getExternalVBaseOffset(BaseDecl, BaseOffset))
2834 BaseOffset = Size;
2835 } else
2836 BaseOffset = Size.alignTo(Info.Alignment);
2837
2838 assert(BaseOffset >= Size && "base offset already allocated")((BaseOffset >= Size && "base offset already allocated"
) ? static_cast<void> (0) : __assert_fail ("BaseOffset >= Size && \"base offset already allocated\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2838, __PRETTY_FUNCTION__))
;
2839
2840 VBases.insert(std::make_pair(BaseDecl,
2841 ASTRecordLayout::VBaseInfo(BaseOffset, HasVtordisp)));
2842 Size = BaseOffset + BaseLayout.getNonVirtualSize();
2843 PreviousBaseLayout = &BaseLayout;
2844 }
2845}
2846
2847void MicrosoftRecordLayoutBuilder::finalizeLayout(const RecordDecl *RD) {
2848 // Respect required alignment. Note that in 32-bit mode Required alignment
2849 // may be 0 and cause size not to be updated.
2850 DataSize = Size;
2851 if (!RequiredAlignment.isZero()) {
2852 Alignment = std::max(Alignment, RequiredAlignment);
2853 auto RoundingAlignment = Alignment;
2854 if (!MaxFieldAlignment.isZero())
2855 RoundingAlignment = std::min(RoundingAlignment, MaxFieldAlignment);
2856 RoundingAlignment = std::max(RoundingAlignment, RequiredAlignment);
2857 Size = Size.alignTo(RoundingAlignment);
2858 }
2859 if (Size.isZero()) {
2860 if (!recordUsesEBO(RD) || !cast<CXXRecordDecl>(RD)->isEmpty()) {
2861 EndsWithZeroSizedObject = true;
2862 LeadsWithZeroSizedBase = true;
2863 }
2864 // Zero-sized structures have size equal to their alignment if a
2865 // __declspec(align) came into play.
2866 if (RequiredAlignment >= MinEmptyStructSize)
2867 Size = Alignment;
2868 else
2869 Size = MinEmptyStructSize;
2870 }
2871
2872 if (UseExternalLayout) {
2873 Size = Context.toCharUnitsFromBits(External.Size);
2874 if (External.Align)
2875 Alignment = Context.toCharUnitsFromBits(External.Align);
2876 }
2877}
2878
2879// Recursively walks the non-virtual bases of a class and determines if any of
2880// them are in the bases with overridden methods set.
2881static bool
2882RequiresVtordisp(const llvm::SmallPtrSetImpl<const CXXRecordDecl *> &
2883 BasesWithOverriddenMethods,
2884 const CXXRecordDecl *RD) {
2885 if (BasesWithOverriddenMethods.count(RD))
2886 return true;
2887 // If any of a virtual bases non-virtual bases (recursively) requires a
2888 // vtordisp than so does this virtual base.
2889 for (const CXXBaseSpecifier &Base : RD->bases())
2890 if (!Base.isVirtual() &&
2891 RequiresVtordisp(BasesWithOverriddenMethods,
2892 Base.getType()->getAsCXXRecordDecl()))
2893 return true;
2894 return false;
2895}
2896
2897void MicrosoftRecordLayoutBuilder::computeVtorDispSet(
2898 llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtordispSet,
2899 const CXXRecordDecl *RD) const {
2900 // /vd2 or #pragma vtordisp(2): Always use vtordisps for virtual bases with
2901 // vftables.
2902 if (RD->getMSVtorDispMode() == MSVtorDispAttr::ForVFTable) {
2903 for (const CXXBaseSpecifier &Base : RD->vbases()) {
2904 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2905 const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
2906 if (Layout.hasExtendableVFPtr())
2907 HasVtordispSet.insert(BaseDecl);
2908 }
2909 return;
2910 }
2911
2912 // If any of our bases need a vtordisp for this type, so do we. Check our
2913 // direct bases for vtordisp requirements.
2914 for (const CXXBaseSpecifier &Base : RD->bases()) {
2915 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2916 const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
2917 for (const auto &bi : Layout.getVBaseOffsetsMap())
2918 if (bi.second.hasVtorDisp())
2919 HasVtordispSet.insert(bi.first);
2920 }
2921 // We don't introduce any additional vtordisps if either:
2922 // * A user declared constructor or destructor aren't declared.
2923 // * #pragma vtordisp(0) or the /vd0 flag are in use.
2924 if ((!RD->hasUserDeclaredConstructor() && !RD->hasUserDeclaredDestructor()) ||
2925 RD->getMSVtorDispMode() == MSVtorDispAttr::Never)
2926 return;
2927 // /vd1 or #pragma vtordisp(1): Try to guess based on whether we think it's
2928 // possible for a partially constructed object with virtual base overrides to
2929 // escape a non-trivial constructor.
2930 assert(RD->getMSVtorDispMode() == MSVtorDispAttr::ForVBaseOverride)((RD->getMSVtorDispMode() == MSVtorDispAttr::ForVBaseOverride
) ? static_cast<void> (0) : __assert_fail ("RD->getMSVtorDispMode() == MSVtorDispAttr::ForVBaseOverride"
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2930, __PRETTY_FUNCTION__))
;
2931 // Compute a set of base classes which define methods we override. A virtual
2932 // base in this set will require a vtordisp. A virtual base that transitively
2933 // contains one of these bases as a non-virtual base will also require a
2934 // vtordisp.
2935 llvm::SmallPtrSet<const CXXMethodDecl *, 8> Work;
2936 llvm::SmallPtrSet<const CXXRecordDecl *, 2> BasesWithOverriddenMethods;
2937 // Seed the working set with our non-destructor, non-pure virtual methods.
2938 for (const CXXMethodDecl *MD : RD->methods())
2939 if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD) && !MD->isPure())
2940 Work.insert(MD);
2941 while (!Work.empty()) {
2942 const CXXMethodDecl *MD = *Work.begin();
2943 auto MethodRange = MD->overridden_methods();
2944 // If a virtual method has no-overrides it lives in its parent's vtable.
2945 if (MethodRange.begin() == MethodRange.end())
2946 BasesWithOverriddenMethods.insert(MD->getParent());
2947 else
2948 Work.insert(MethodRange.begin(), MethodRange.end());
2949 // We've finished processing this element, remove it from the working set.
2950 Work.erase(MD);
2951 }
2952 // For each of our virtual bases, check if it is in the set of overridden
2953 // bases or if it transitively contains a non-virtual base that is.
2954 for (const CXXBaseSpecifier &Base : RD->vbases()) {
2955 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2956 if (!HasVtordispSet.count(BaseDecl) &&
2957 RequiresVtordisp(BasesWithOverriddenMethods, BaseDecl))
2958 HasVtordispSet.insert(BaseDecl);
2959 }
2960}
2961
2962/// getASTRecordLayout - Get or compute information about the layout of the
2963/// specified record (struct/union/class), which indicates its size and field
2964/// position information.
2965const ASTRecordLayout &
2966ASTContext::getASTRecordLayout(const RecordDecl *D) const {
2967 // These asserts test different things. A record has a definition
2968 // as soon as we begin to parse the definition. That definition is
2969 // not a complete definition (which is what isDefinition() tests)
2970 // until we *finish* parsing the definition.
2971
2972 if (D->hasExternalLexicalStorage() && !D->getDefinition())
5
Assuming the condition is false
2973 getExternalSource()->CompleteType(const_cast<RecordDecl*>(D));
2974
2975 D = D->getDefinition();
2976 assert(D && "Cannot get layout of forward declarations!")((D && "Cannot get layout of forward declarations!") ?
static_cast<void> (0) : __assert_fail ("D && \"Cannot get layout of forward declarations!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2976, __PRETTY_FUNCTION__))
;
2977 assert(!D->isInvalidDecl() && "Cannot get layout of invalid decl!")((!D->isInvalidDecl() && "Cannot get layout of invalid decl!"
) ? static_cast<void> (0) : __assert_fail ("!D->isInvalidDecl() && \"Cannot get layout of invalid decl!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2977, __PRETTY_FUNCTION__))
;
2978 assert(D->isCompleteDefinition() && "Cannot layout type before complete!")((D->isCompleteDefinition() && "Cannot layout type before complete!"
) ? static_cast<void> (0) : __assert_fail ("D->isCompleteDefinition() && \"Cannot layout type before complete!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2978, __PRETTY_FUNCTION__))
;
2979
2980 // Look up this layout, if already laid out, return what we have.
2981 // Note that we can't save a reference to the entry because this function
2982 // is recursive.
2983 const ASTRecordLayout *Entry = ASTRecordLayouts[D];
2984 if (Entry) return *Entry;
6
Assuming 'Entry' is null
7
Taking false branch
2985
2986 const ASTRecordLayout *NewEntry = nullptr;
2987
2988 if (isMsLayout(*this)) {
8
Taking false branch
2989 MicrosoftRecordLayoutBuilder Builder(*this);
2990 if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
2991 Builder.cxxLayout(RD);
2992 NewEntry = new (*this) ASTRecordLayout(
2993 *this, Builder.Size, Builder.Alignment, Builder.Alignment,
2994 Builder.RequiredAlignment,
2995 Builder.HasOwnVFPtr, Builder.HasOwnVFPtr || Builder.PrimaryBase,
2996 Builder.VBPtrOffset, Builder.DataSize, Builder.FieldOffsets,
2997 Builder.NonVirtualSize, Builder.Alignment, CharUnits::Zero(),
2998 Builder.PrimaryBase, false, Builder.SharedVBPtrBase,
2999 Builder.EndsWithZeroSizedObject, Builder.LeadsWithZeroSizedBase,
3000 Builder.Bases, Builder.VBases);
3001 } else {
3002 Builder.layout(D);
3003 NewEntry = new (*this) ASTRecordLayout(
3004 *this, Builder.Size, Builder.Alignment, Builder.Alignment,
3005 Builder.RequiredAlignment,
3006 Builder.Size, Builder.FieldOffsets);
3007 }
3008 } else {
3009 if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
9
Taking true branch
3010 EmptySubobjectMap EmptySubobjects(*this, RD);
3011 ItaniumRecordLayoutBuilder Builder(*this, &EmptySubobjects);
3012 Builder.Layout(RD);
10
Calling 'ItaniumRecordLayoutBuilder::Layout'
3013
3014 // In certain situations, we are allowed to lay out objects in the
3015 // tail-padding of base classes. This is ABI-dependent.
3016 // FIXME: this should be stored in the record layout.
3017 bool skipTailPadding =
3018 mustSkipTailPadding(getTargetInfo().getCXXABI(), RD);
3019
3020 // FIXME: This should be done in FinalizeLayout.
3021 CharUnits DataSize =
3022 skipTailPadding ? Builder.getSize() : Builder.getDataSize();
3023 CharUnits NonVirtualSize =
3024 skipTailPadding ? DataSize : Builder.NonVirtualSize;
3025 NewEntry = new (*this) ASTRecordLayout(
3026 *this, Builder.getSize(), Builder.Alignment, Builder.UnadjustedAlignment,
3027 /*RequiredAlignment : used by MS-ABI)*/
3028 Builder.Alignment, Builder.HasOwnVFPtr, RD->isDynamicClass(),
3029 CharUnits::fromQuantity(-1), DataSize, Builder.FieldOffsets,
3030 NonVirtualSize, Builder.NonVirtualAlignment,
3031 EmptySubobjects.SizeOfLargestEmptySubobject, Builder.PrimaryBase,
3032 Builder.PrimaryBaseIsVirtual, nullptr, false, false, Builder.Bases,
3033 Builder.VBases);
3034 } else {
3035 ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3036 Builder.Layout(D);
3037
3038 NewEntry = new (*this) ASTRecordLayout(
3039 *this, Builder.getSize(), Builder.Alignment, Builder.UnadjustedAlignment,
3040 /*RequiredAlignment : used by MS-ABI)*/
3041 Builder.Alignment, Builder.getSize(), Builder.FieldOffsets);
3042 }
3043 }
3044
3045 ASTRecordLayouts[D] = NewEntry;
3046
3047 if (getLangOpts().DumpRecordLayouts) {
3048 llvm::outs() << "\n*** Dumping AST Record Layout\n";
3049 DumpRecordLayout(D, llvm::outs(), getLangOpts().DumpRecordLayoutsSimple);
3050 }
3051
3052 return *NewEntry;
3053}
3054
3055const CXXMethodDecl *ASTContext::getCurrentKeyFunction(const CXXRecordDecl *RD) {
3056 if (!getTargetInfo().getCXXABI().hasKeyFunctions())
3057 return nullptr;
3058
3059 assert(RD->getDefinition() && "Cannot get key function for forward decl!")((RD->getDefinition() && "Cannot get key function for forward decl!"
) ? static_cast<void> (0) : __assert_fail ("RD->getDefinition() && \"Cannot get key function for forward decl!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3059, __PRETTY_FUNCTION__))
;
3060 RD = RD->getDefinition();
3061
3062 // Beware:
3063 // 1) computing the key function might trigger deserialization, which might
3064 // invalidate iterators into KeyFunctions
3065 // 2) 'get' on the LazyDeclPtr might also trigger deserialization and
3066 // invalidate the LazyDeclPtr within the map itself
3067 LazyDeclPtr Entry = KeyFunctions[RD];
3068 const Decl *Result =
3069 Entry ? Entry.get(getExternalSource()) : computeKeyFunction(*this, RD);
3070
3071 // Store it back if it changed.
3072 if (Entry.isOffset() || Entry.isValid() != bool(Result))
3073 KeyFunctions[RD] = const_cast<Decl*>(Result);
3074
3075 return cast_or_null<CXXMethodDecl>(Result);
3076}
3077
3078void ASTContext::setNonKeyFunction(const CXXMethodDecl *Method) {
3079 assert(Method == Method->getFirstDecl() &&((Method == Method->getFirstDecl() && "not working with method declaration from class definition"
) ? static_cast<void> (0) : __assert_fail ("Method == Method->getFirstDecl() && \"not working with method declaration from class definition\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3080, __PRETTY_FUNCTION__))
3080 "not working with method declaration from class definition")((Method == Method->getFirstDecl() && "not working with method declaration from class definition"
) ? static_cast<void> (0) : __assert_fail ("Method == Method->getFirstDecl() && \"not working with method declaration from class definition\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3080, __PRETTY_FUNCTION__))
;
3081
3082 // Look up the cache entry. Since we're working with the first
3083 // declaration, its parent must be the class definition, which is
3084 // the correct key for the KeyFunctions hash.
3085 const auto &Map = KeyFunctions;
3086 auto I = Map.find(Method->getParent());
3087
3088 // If it's not cached, there's nothing to do.
3089 if (I == Map.end()) return;
3090
3091 // If it is cached, check whether it's the target method, and if so,
3092 // remove it from the cache. Note, the call to 'get' might invalidate
3093 // the iterator and the LazyDeclPtr object within the map.
3094 LazyDeclPtr Ptr = I->second;
3095 if (Ptr.get(getExternalSource()) == Method) {
3096 // FIXME: remember that we did this for module / chained PCH state?
3097 KeyFunctions.erase(Method->getParent());
3098 }
3099}
3100
3101static uint64_t getFieldOffset(const ASTContext &C, const FieldDecl *FD) {
3102 const ASTRecordLayout &Layout = C.getASTRecordLayout(FD->getParent());
4
Calling 'ASTContext::getASTRecordLayout'
3103 return Layout.getFieldOffset(FD->getFieldIndex());
3104}
3105
3106uint64_t ASTContext::getFieldOffset(const ValueDecl *VD) const {
3107 uint64_t OffsetInBits;
3108 if (const FieldDecl *FD = dyn_cast<FieldDecl>(VD)) {
1
Taking false branch
3109 OffsetInBits = ::getFieldOffset(*this, FD);
3110 } else {
3111 const IndirectFieldDecl *IFD = cast<IndirectFieldDecl>(VD);
3112
3113 OffsetInBits = 0;
3114 for (const NamedDecl *ND : IFD->chain())
2
Assuming '__begin2' is not equal to '__end2'
3115 OffsetInBits += ::getFieldOffset(*this, cast<FieldDecl>(ND));
3
Calling 'getFieldOffset'
3116 }
3117
3118 return OffsetInBits;
3119}
3120
3121uint64_t ASTContext::lookupFieldBitOffset(const ObjCInterfaceDecl *OID,
3122 const ObjCImplementationDecl *ID,
3123 const ObjCIvarDecl *Ivar) const {
3124 const ObjCInterfaceDecl *Container = Ivar->getContainingInterface();
3125
3126 // FIXME: We should eliminate the need to have ObjCImplementationDecl passed
3127 // in here; it should never be necessary because that should be the lexical
3128 // decl context for the ivar.
3129
3130 // If we know have an implementation (and the ivar is in it) then
3131 // look up in the implementation layout.
3132 const ASTRecordLayout *RL;
3133 if (ID && declaresSameEntity(ID->getClassInterface(), Container))
3134 RL = &getASTObjCImplementationLayout(ID);
3135 else
3136 RL = &getASTObjCInterfaceLayout(Container);
3137
3138 // Compute field index.
3139 //
3140 // FIXME: The index here is closely tied to how ASTContext::getObjCLayout is
3141 // implemented. This should be fixed to get the information from the layout
3142 // directly.
3143 unsigned Index = 0;
3144
3145 for (const ObjCIvarDecl *IVD = Container->all_declared_ivar_begin();
3146 IVD; IVD = IVD->getNextIvar()) {
3147 if (Ivar == IVD)
3148 break;
3149 ++Index;
3150 }
3151 assert(Index < RL->getFieldCount() && "Ivar is not inside record layout!")((Index < RL->getFieldCount() && "Ivar is not inside record layout!"
) ? static_cast<void> (0) : __assert_fail ("Index < RL->getFieldCount() && \"Ivar is not inside record layout!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3151, __PRETTY_FUNCTION__))
;
3152
3153 return RL->getFieldOffset(Index);
3154}
3155
3156/// getObjCLayout - Get or compute information about the layout of the
3157/// given interface.
3158///
3159/// \param Impl - If given, also include the layout of the interface's
3160/// implementation. This may differ by including synthesized ivars.
3161const ASTRecordLayout &
3162ASTContext::getObjCLayout(const ObjCInterfaceDecl *D,
3163 const ObjCImplementationDecl *Impl) const {
3164 // Retrieve the definition
3165 if (D->hasExternalLexicalStorage() && !D->getDefinition())
3166 getExternalSource()->CompleteType(const_cast<ObjCInterfaceDecl*>(D));
3167 D = D->getDefinition();
3168 assert(D && D->isThisDeclarationADefinition() && "Invalid interface decl!")((D && D->isThisDeclarationADefinition() &&
"Invalid interface decl!") ? static_cast<void> (0) : __assert_fail
("D && D->isThisDeclarationADefinition() && \"Invalid interface decl!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3168, __PRETTY_FUNCTION__))
;
3169
3170 // Look up this layout, if already laid out, return what we have.
3171 const ObjCContainerDecl *Key =
3172 Impl ? (const ObjCContainerDecl*) Impl : (const ObjCContainerDecl*) D;
3173 if (const ASTRecordLayout *Entry = ObjCLayouts[Key])
3174 return *Entry;
3175
3176 // Add in synthesized ivar count if laying out an implementation.
3177 if (Impl) {
3178 unsigned SynthCount = CountNonClassIvars(D);
3179 // If there aren't any synthesized ivars then reuse the interface
3180 // entry. Note we can't cache this because we simply free all
3181 // entries later; however we shouldn't look up implementations
3182 // frequently.
3183 if (SynthCount == 0)
3184 return getObjCLayout(D, nullptr);
3185 }
3186
3187 ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3188 Builder.Layout(D);
3189
3190 const ASTRecordLayout *NewEntry =
3191 new (*this) ASTRecordLayout(*this, Builder.getSize(),
3192 Builder.Alignment,
3193 Builder.UnadjustedAlignment,
3194 /*RequiredAlignment : used by MS-ABI)*/
3195 Builder.Alignment,
3196 Builder.getDataSize(),
3197 Builder.FieldOffsets);
3198
3199 ObjCLayouts[Key] = NewEntry;
3200
3201 return *NewEntry;
3202}
3203
3204static void PrintOffset(raw_ostream &OS,
3205 CharUnits Offset, unsigned IndentLevel) {
3206 OS << llvm::format("%10" PRId64"l" "d" " | ", (int64_t)Offset.getQuantity());
3207 OS.indent(IndentLevel * 2);
3208}
3209
3210static void PrintBitFieldOffset(raw_ostream &OS, CharUnits Offset,
3211 unsigned Begin, unsigned Width,
3212 unsigned IndentLevel) {
3213 llvm::SmallString<10> Buffer;
3214 {
3215 llvm::raw_svector_ostream BufferOS(Buffer);
3216 BufferOS << Offset.getQuantity() << ':';
3217 if (Width == 0) {
3218 BufferOS << '-';
3219 } else {
3220 BufferOS << Begin << '-' << (Begin + Width - 1);
3221 }
3222 }
3223
3224 OS << llvm::right_justify(Buffer, 10) << " | ";
3225 OS.indent(IndentLevel * 2);
3226}
3227
3228static void PrintIndentNoOffset(raw_ostream &OS, unsigned IndentLevel) {
3229 OS << " | ";
3230 OS.indent(IndentLevel * 2);
3231}
3232
3233static void DumpRecordLayout(raw_ostream &OS, const RecordDecl *RD,
3234 const ASTContext &C,
3235 CharUnits Offset,
3236 unsigned IndentLevel,
3237 const char* Description,
3238 bool PrintSizeInfo,
3239 bool IncludeVirtualBases) {
3240 const ASTRecordLayout &Layout = C.getASTRecordLayout(RD);
3241 auto CXXRD = dyn_cast<CXXRecordDecl>(RD);
3242
3243 PrintOffset(OS, Offset, IndentLevel);
3244 OS << C.getTypeDeclType(const_cast<RecordDecl*>(RD)).getAsString();
3245 if (Description)
3246 OS << ' ' << Description;
3247 if (CXXRD && CXXRD->isEmpty())
3248 OS << " (empty)";
3249 OS << '\n';
3250
3251 IndentLevel++;
3252
3253 // Dump bases.
3254 if (CXXRD) {
3255 const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
3256 bool HasOwnVFPtr = Layout.hasOwnVFPtr();
3257 bool HasOwnVBPtr = Layout.hasOwnVBPtr();
3258
3259 // Vtable pointer.
3260 if (CXXRD->isDynamicClass() && !PrimaryBase && !isMsLayout(C)) {
3261 PrintOffset(OS, Offset, IndentLevel);
3262 OS << '(' << *RD << " vtable pointer)\n";
3263 } else if (HasOwnVFPtr) {
3264 PrintOffset(OS, Offset, IndentLevel);
3265 // vfptr (for Microsoft C++ ABI)
3266 OS << '(' << *RD << " vftable pointer)\n";
3267 }
3268
3269 // Collect nvbases.
3270 SmallVector<const CXXRecordDecl *, 4> Bases;
3271 for (const CXXBaseSpecifier &Base : CXXRD->bases()) {
3272 assert(!Base.getType()->isDependentType() &&((!Base.getType()->isDependentType() && "Cannot layout class with dependent bases."
) ? static_cast<void> (0) : __assert_fail ("!Base.getType()->isDependentType() && \"Cannot layout class with dependent bases.\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3273, __PRETTY_FUNCTION__))
3273 "Cannot layout class with dependent bases.")((!Base.getType()->isDependentType() && "Cannot layout class with dependent bases."
) ? static_cast<void> (0) : __assert_fail ("!Base.getType()->isDependentType() && \"Cannot layout class with dependent bases.\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3273, __PRETTY_FUNCTION__))
;
3274 if (!Base.isVirtual())
3275 Bases.push_back(Base.getType()->getAsCXXRecordDecl());
3276 }
3277
3278 // Sort nvbases by offset.
3279 std::stable_sort(Bases.begin(), Bases.end(),
3280 [&](const CXXRecordDecl *L, const CXXRecordDecl *R) {
3281 return Layout.getBaseClassOffset(L) < Layout.getBaseClassOffset(R);
3282 });
3283
3284 // Dump (non-virtual) bases
3285 for (const CXXRecordDecl *Base : Bases) {
3286 CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base);
3287 DumpRecordLayout(OS, Base, C, BaseOffset, IndentLevel,
3288 Base == PrimaryBase ? "(primary base)" : "(base)",
3289 /*PrintSizeInfo=*/false,
3290 /*IncludeVirtualBases=*/false);
3291 }
3292
3293 // vbptr (for Microsoft C++ ABI)
3294 if (HasOwnVBPtr) {
3295 PrintOffset(OS, Offset + Layout.getVBPtrOffset(), IndentLevel);
3296 OS << '(' << *RD << " vbtable pointer)\n";
3297 }
3298 }
3299
3300 // Dump fields.
3301 uint64_t FieldNo = 0;
3302 for (RecordDecl::field_iterator I = RD->field_begin(),
3303 E = RD->field_end(); I != E; ++I, ++FieldNo) {
3304 const FieldDecl &Field = **I;
3305 uint64_t LocalFieldOffsetInBits = Layout.getFieldOffset(FieldNo);
3306 CharUnits FieldOffset =
3307 Offset + C.toCharUnitsFromBits(LocalFieldOffsetInBits);
3308
3309 // Recursively dump fields of record type.
3310 if (auto RT = Field.getType()->getAs<RecordType>()) {
3311 DumpRecordLayout(OS, RT->getDecl(), C, FieldOffset, IndentLevel,
3312 Field.getName().data(),
3313 /*PrintSizeInfo=*/false,
3314 /*IncludeVirtualBases=*/true);
3315 continue;
3316 }
3317
3318 if (Field.isBitField()) {
3319 uint64_t LocalFieldByteOffsetInBits = C.toBits(FieldOffset - Offset);
3320 unsigned Begin = LocalFieldOffsetInBits - LocalFieldByteOffsetInBits;
3321 unsigned Width = Field.getBitWidthValue(C);
3322 PrintBitFieldOffset(OS, FieldOffset, Begin, Width, IndentLevel);
3323 } else {
3324 PrintOffset(OS, FieldOffset, IndentLevel);
3325 }
3326 OS << Field.getType().getAsString() << ' ' << Field << '\n';
3327 }
3328
3329 // Dump virtual bases.
3330 if (CXXRD && IncludeVirtualBases) {
3331 const ASTRecordLayout::VBaseOffsetsMapTy &VtorDisps =
3332 Layout.getVBaseOffsetsMap();
3333
3334 for (const CXXBaseSpecifier &Base : CXXRD->vbases()) {
3335 assert(Base.isVirtual() && "Found non-virtual class!")((Base.isVirtual() && "Found non-virtual class!") ? static_cast
<void> (0) : __assert_fail ("Base.isVirtual() && \"Found non-virtual class!\""
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3335, __PRETTY_FUNCTION__))
;
3336 const CXXRecordDecl *VBase = Base.getType()->getAsCXXRecordDecl();
3337
3338 CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBase);
3339
3340 if (VtorDisps.find(VBase)->second.hasVtorDisp()) {
3341 PrintOffset(OS, VBaseOffset - CharUnits::fromQuantity(4), IndentLevel);
3342 OS << "(vtordisp for vbase " << *VBase << ")\n";
3343 }
3344
3345 DumpRecordLayout(OS, VBase, C, VBaseOffset, IndentLevel,
3346 VBase == Layout.getPrimaryBase() ?
3347 "(primary virtual base)" : "(virtual base)",
3348 /*PrintSizeInfo=*/false,
3349 /*IncludeVirtualBases=*/false);
3350 }
3351 }
3352
3353 if (!PrintSizeInfo) return;
3354
3355 PrintIndentNoOffset(OS, IndentLevel - 1);
3356 OS << "[sizeof=" << Layout.getSize().getQuantity();
3357 if (CXXRD && !isMsLayout(C))
3358 OS << ", dsize=" << Layout.getDataSize().getQuantity();
3359 OS << ", align=" << Layout.getAlignment().getQuantity();
3360
3361 if (CXXRD) {
3362 OS << ",\n";
3363 PrintIndentNoOffset(OS, IndentLevel - 1);
3364 OS << " nvsize=" << Layout.getNonVirtualSize().getQuantity();
3365 OS << ", nvalign=" << Layout.getNonVirtualAlignment().getQuantity();
3366 }
3367 OS << "]\n";
3368}
3369
3370void ASTContext::DumpRecordLayout(const RecordDecl *RD,
3371 raw_ostream &OS,
3372 bool Simple) const {
3373 if (!Simple) {
3374 ::DumpRecordLayout(OS, RD, *this, CharUnits(), 0, nullptr,
3375 /*PrintSizeInfo*/true,
3376 /*IncludeVirtualBases=*/true);
3377 return;
3378 }
3379
3380 // The "simple" format is designed to be parsed by the
3381 // layout-override testing code. There shouldn't be any external
3382 // uses of this format --- when LLDB overrides a layout, it sets up
3383 // the data structures directly --- so feel free to adjust this as
3384 // you like as long as you also update the rudimentary parser for it
3385 // in libFrontend.
3386
3387 const ASTRecordLayout &Info = getASTRecordLayout(RD);
3388 OS << "Type: " << getTypeDeclType(RD).getAsString() << "\n";
3389 OS << "\nLayout: ";
3390 OS << "<ASTRecordLayout\n";
3391 OS << " Size:" << toBits(Info.getSize()) << "\n";
3392 if (!isMsLayout(*this))
3393 OS << " DataSize:" << toBits(Info.getDataSize()) << "\n";
3394 OS << " Alignment:" << toBits(Info.getAlignment()) << "\n";
3395 OS << " FieldOffsets: [";
3396 for (unsigned i = 0, e = Info.getFieldCount(); i != e; ++i) {
3397 if (i) OS << ", ";
3398 OS << Info.getFieldOffset(i);
3399 }
3400 OS << "]>\n";
3401}