Bug Summary

File:tools/clang/lib/AST/RecordLayoutBuilder.cpp
Warning:line 1141, 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 -analyzer-config-compatibility-mode=true -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-9/lib/clang/9.0.0 -D CLANG_VENDOR="Debian " -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-9~svn358860/build-llvm/tools/clang/lib/AST -I /build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/AST -I /build/llvm-toolchain-snapshot-9~svn358860/tools/clang/include -I /build/llvm-toolchain-snapshot-9~svn358860/build-llvm/tools/clang/include -I /build/llvm-toolchain-snapshot-9~svn358860/build-llvm/include -I /build/llvm-toolchain-snapshot-9~svn358860/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/9.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-9/lib/clang/9.0.0/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-9~svn358860/build-llvm/tools/clang/lib/AST -fdebug-prefix-map=/build/llvm-toolchain-snapshot-9~svn358860=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -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-2019-04-22-050718-5320-1 -x c++ /build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp -faddrsig
1//=== RecordLayoutBuilder.cpp - Helper class for building record layouts ---==//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "clang/AST/RecordLayout.h"
10#include "clang/AST/ASTContext.h"
11#include "clang/AST/ASTDiagnostic.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 "llvm/ADT/SmallSet.h"
20#include "llvm/Support/Format.h"
21#include "llvm/Support/MathExtras.h"
22
23using namespace clang;
24
25namespace {
26
27/// BaseSubobjectInfo - Represents a single base subobject in a complete class.
28/// For a class hierarchy like
29///
30/// class A { };
31/// class B : A { };
32/// class C : A, B { };
33///
34/// The BaseSubobjectInfo graph for C will have three BaseSubobjectInfo
35/// instances, one for B and two for A.
36///
37/// If a base is virtual, it will only have one BaseSubobjectInfo allocated.
38struct BaseSubobjectInfo {
39 /// Class - The class for this base info.
40 const CXXRecordDecl *Class;
41
42 /// IsVirtual - Whether the BaseInfo represents a virtual base or not.
43 bool IsVirtual;
44
45 /// Bases - Information about the base subobjects.
46 SmallVector<BaseSubobjectInfo*, 4> Bases;
47
48 /// PrimaryVirtualBaseInfo - Holds the base info for the primary virtual base
49 /// of this base info (if one exists).
50 BaseSubobjectInfo *PrimaryVirtualBaseInfo;
51
52 // FIXME: Document.
53 const BaseSubobjectInfo *Derived;
54};
55
56/// Externally provided layout. Typically used when the AST source, such
57/// as DWARF, lacks all the information that was available at compile time, such
58/// as alignment attributes on fields and pragmas in effect.
59struct ExternalLayout {
60 ExternalLayout() : Size(0), Align(0) {}
61
62 /// Overall record size in bits.
63 uint64_t Size;
64
65 /// Overall record alignment in bits.
66 uint64_t Align;
67
68 /// Record field offsets in bits.
69 llvm::DenseMap<const FieldDecl *, uint64_t> FieldOffsets;
70
71 /// Direct, non-virtual base offsets.
72 llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsets;
73
74 /// Virtual base offsets.
75 llvm::DenseMap<const CXXRecordDecl *, CharUnits> VirtualBaseOffsets;
76
77 /// Get the offset of the given field. The external source must provide
78 /// entries for all fields in the record.
79 uint64_t getExternalFieldOffset(const FieldDecl *FD) {
80 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 81, __PRETTY_FUNCTION__))
81 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 81, __PRETTY_FUNCTION__))
;
82 return FieldOffsets[FD];
83 }
84
85 bool getExternalNVBaseOffset(const CXXRecordDecl *RD, CharUnits &BaseOffset) {
86 auto Known = BaseOffsets.find(RD);
87 if (Known == BaseOffsets.end())
88 return false;
89 BaseOffset = Known->second;
90 return true;
91 }
92
93 bool getExternalVBaseOffset(const CXXRecordDecl *RD, CharUnits &BaseOffset) {
94 auto Known = VirtualBaseOffsets.find(RD);
95 if (Known == VirtualBaseOffsets.end())
96 return false;
97 BaseOffset = Known->second;
98 return true;
99 }
100};
101
102/// EmptySubobjectMap - Keeps track of which empty subobjects exist at different
103/// offsets while laying out a C++ class.
104class EmptySubobjectMap {
105 const ASTContext &Context;
106 uint64_t CharWidth;
107
108 /// Class - The class whose empty entries we're keeping track of.
109 const CXXRecordDecl *Class;
110
111 /// EmptyClassOffsets - A map from offsets to empty record decls.
112 typedef llvm::TinyPtrVector<const CXXRecordDecl *> ClassVectorTy;
113 typedef llvm::DenseMap<CharUnits, ClassVectorTy> EmptyClassOffsetsMapTy;
114 EmptyClassOffsetsMapTy EmptyClassOffsets;
115
116 /// MaxEmptyClassOffset - The highest offset known to contain an empty
117 /// base subobject.
118 CharUnits MaxEmptyClassOffset;
119
120 /// ComputeEmptySubobjectSizes - Compute the size of the largest base or
121 /// member subobject that is empty.
122 void ComputeEmptySubobjectSizes();
123
124 void AddSubobjectAtOffset(const CXXRecordDecl *RD, CharUnits Offset);
125
126 void UpdateEmptyBaseSubobjects(const BaseSubobjectInfo *Info,
127 CharUnits Offset, bool PlacingEmptyBase);
128
129 void UpdateEmptyFieldSubobjects(const CXXRecordDecl *RD,
130 const CXXRecordDecl *Class,
131 CharUnits Offset);
132 void UpdateEmptyFieldSubobjects(const FieldDecl *FD, CharUnits Offset);
133
134 /// AnyEmptySubobjectsBeyondOffset - Returns whether there are any empty
135 /// subobjects beyond the given offset.
136 bool AnyEmptySubobjectsBeyondOffset(CharUnits Offset) const {
137 return Offset <= MaxEmptyClassOffset;
138 }
139
140 CharUnits
141 getFieldOffset(const ASTRecordLayout &Layout, unsigned FieldNo) const {
142 uint64_t FieldOffset = Layout.getFieldOffset(FieldNo);
143 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 144, __PRETTY_FUNCTION__))
144 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 144, __PRETTY_FUNCTION__))
;
145
146 return Context.toCharUnitsFromBits(FieldOffset);
147 }
148
149protected:
150 bool CanPlaceSubobjectAtOffset(const CXXRecordDecl *RD,
151 CharUnits Offset) const;
152
153 bool CanPlaceBaseSubobjectAtOffset(const BaseSubobjectInfo *Info,
154 CharUnits Offset);
155
156 bool CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD,
157 const CXXRecordDecl *Class,
158 CharUnits Offset) const;
159 bool CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD,
160 CharUnits Offset) const;
161
162public:
163 /// This holds the size of the largest empty subobject (either a base
164 /// or a member). Will be zero if the record being built doesn't contain
165 /// any empty classes.
166 CharUnits SizeOfLargestEmptySubobject;
167
168 EmptySubobjectMap(const ASTContext &Context, const CXXRecordDecl *Class)
169 : Context(Context), CharWidth(Context.getCharWidth()), Class(Class) {
170 ComputeEmptySubobjectSizes();
171 }
172
173 /// CanPlaceBaseAtOffset - Return whether the given base class can be placed
174 /// at the given offset.
175 /// Returns false if placing the record will result in two components
176 /// (direct or indirect) of the same type having the same offset.
177 bool CanPlaceBaseAtOffset(const BaseSubobjectInfo *Info,
178 CharUnits Offset);
179
180 /// CanPlaceFieldAtOffset - Return whether a field can be placed at the given
181 /// offset.
182 bool CanPlaceFieldAtOffset(const FieldDecl *FD, CharUnits Offset);
183};
184
185void EmptySubobjectMap::ComputeEmptySubobjectSizes() {
186 // Check the bases.
187 for (const CXXBaseSpecifier &Base : Class->bases()) {
188 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
189
190 CharUnits EmptySize;
191 const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
192 if (BaseDecl->isEmpty()) {
193 // If the class decl is empty, get its size.
194 EmptySize = Layout.getSize();
195 } else {
196 // Otherwise, we get the largest empty subobject for the decl.
197 EmptySize = Layout.getSizeOfLargestEmptySubobject();
198 }
199
200 if (EmptySize > SizeOfLargestEmptySubobject)
201 SizeOfLargestEmptySubobject = EmptySize;
202 }
203
204 // Check the fields.
205 for (const FieldDecl *FD : Class->fields()) {
206 const RecordType *RT =
207 Context.getBaseElementType(FD->getType())->getAs<RecordType>();
208
209 // We only care about record types.
210 if (!RT)
211 continue;
212
213 CharUnits EmptySize;
214 const CXXRecordDecl *MemberDecl = RT->getAsCXXRecordDecl();
215 const ASTRecordLayout &Layout = Context.getASTRecordLayout(MemberDecl);
216 if (MemberDecl->isEmpty()) {
217 // If the class decl is empty, get its size.
218 EmptySize = Layout.getSize();
219 } else {
220 // Otherwise, we get the largest empty subobject for the decl.
221 EmptySize = Layout.getSizeOfLargestEmptySubobject();
222 }
223
224 if (EmptySize > SizeOfLargestEmptySubobject)
225 SizeOfLargestEmptySubobject = EmptySize;
226 }
227}
228
229bool
230EmptySubobjectMap::CanPlaceSubobjectAtOffset(const CXXRecordDecl *RD,
231 CharUnits Offset) const {
232 // We only need to check empty bases.
233 if (!RD->isEmpty())
234 return true;
235
236 EmptyClassOffsetsMapTy::const_iterator I = EmptyClassOffsets.find(Offset);
237 if (I == EmptyClassOffsets.end())
238 return true;
239
240 const ClassVectorTy &Classes = I->second;
241 if (llvm::find(Classes, RD) == Classes.end())
242 return true;
243
244 // There is already an empty class of the same type at this offset.
245 return false;
246}
247
248void EmptySubobjectMap::AddSubobjectAtOffset(const CXXRecordDecl *RD,
249 CharUnits Offset) {
250 // We only care about empty bases.
251 if (!RD->isEmpty())
252 return;
253
254 // If we have empty structures inside a union, we can assign both
255 // the same offset. Just avoid pushing them twice in the list.
256 ClassVectorTy &Classes = EmptyClassOffsets[Offset];
257 if (llvm::is_contained(Classes, RD))
258 return;
259
260 Classes.push_back(RD);
261
262 // Update the empty class offset.
263 if (Offset > MaxEmptyClassOffset)
264 MaxEmptyClassOffset = Offset;
265}
266
267bool
268EmptySubobjectMap::CanPlaceBaseSubobjectAtOffset(const BaseSubobjectInfo *Info,
269 CharUnits Offset) {
270 // We don't have to keep looking past the maximum offset that's known to
271 // contain an empty class.
272 if (!AnyEmptySubobjectsBeyondOffset(Offset))
273 return true;
274
275 if (!CanPlaceSubobjectAtOffset(Info->Class, Offset))
276 return false;
277
278 // Traverse all non-virtual bases.
279 const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
280 for (const BaseSubobjectInfo *Base : Info->Bases) {
281 if (Base->IsVirtual)
282 continue;
283
284 CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
285
286 if (!CanPlaceBaseSubobjectAtOffset(Base, BaseOffset))
287 return false;
288 }
289
290 if (Info->PrimaryVirtualBaseInfo) {
291 BaseSubobjectInfo *PrimaryVirtualBaseInfo = Info->PrimaryVirtualBaseInfo;
292
293 if (Info == PrimaryVirtualBaseInfo->Derived) {
294 if (!CanPlaceBaseSubobjectAtOffset(PrimaryVirtualBaseInfo, Offset))
295 return false;
296 }
297 }
298
299 // Traverse all member variables.
300 unsigned FieldNo = 0;
301 for (CXXRecordDecl::field_iterator I = Info->Class->field_begin(),
302 E = Info->Class->field_end(); I != E; ++I, ++FieldNo) {
303 if (I->isBitField())
304 continue;
305
306 CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
307 if (!CanPlaceFieldSubobjectAtOffset(*I, FieldOffset))
308 return false;
309 }
310
311 return true;
312}
313
314void EmptySubobjectMap::UpdateEmptyBaseSubobjects(const BaseSubobjectInfo *Info,
315 CharUnits Offset,
316 bool PlacingEmptyBase) {
317 if (!PlacingEmptyBase && Offset >= SizeOfLargestEmptySubobject) {
318 // We know that the only empty subobjects that can conflict with empty
319 // subobject of non-empty bases, are empty bases that can be placed at
320 // offset zero. Because of this, we only need to keep track of empty base
321 // subobjects with offsets less than the size of the largest empty
322 // subobject for our class.
323 return;
324 }
325
326 AddSubobjectAtOffset(Info->Class, Offset);
327
328 // Traverse all non-virtual bases.
329 const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
330 for (const BaseSubobjectInfo *Base : Info->Bases) {
331 if (Base->IsVirtual)
332 continue;
333
334 CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
335 UpdateEmptyBaseSubobjects(Base, BaseOffset, PlacingEmptyBase);
336 }
337
338 if (Info->PrimaryVirtualBaseInfo) {
339 BaseSubobjectInfo *PrimaryVirtualBaseInfo = Info->PrimaryVirtualBaseInfo;
340
341 if (Info == PrimaryVirtualBaseInfo->Derived)
342 UpdateEmptyBaseSubobjects(PrimaryVirtualBaseInfo, Offset,
343 PlacingEmptyBase);
344 }
345
346 // Traverse all member variables.
347 unsigned FieldNo = 0;
348 for (CXXRecordDecl::field_iterator I = Info->Class->field_begin(),
349 E = Info->Class->field_end(); I != E; ++I, ++FieldNo) {
350 if (I->isBitField())
351 continue;
352
353 CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
354 UpdateEmptyFieldSubobjects(*I, FieldOffset);
355 }
356}
357
358bool EmptySubobjectMap::CanPlaceBaseAtOffset(const BaseSubobjectInfo *Info,
359 CharUnits Offset) {
360 // If we know this class doesn't have any empty subobjects we don't need to
361 // bother checking.
362 if (SizeOfLargestEmptySubobject.isZero())
363 return true;
364
365 if (!CanPlaceBaseSubobjectAtOffset(Info, Offset))
366 return false;
367
368 // We are able to place the base at this offset. Make sure to update the
369 // empty base subobject map.
370 UpdateEmptyBaseSubobjects(Info, Offset, Info->Class->isEmpty());
371 return true;
372}
373
374bool
375EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD,
376 const CXXRecordDecl *Class,
377 CharUnits Offset) const {
378 // We don't have to keep looking past the maximum offset that's known to
379 // contain an empty class.
380 if (!AnyEmptySubobjectsBeyondOffset(Offset))
381 return true;
382
383 if (!CanPlaceSubobjectAtOffset(RD, Offset))
384 return false;
385
386 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
387
388 // Traverse all non-virtual bases.
389 for (const CXXBaseSpecifier &Base : RD->bases()) {
390 if (Base.isVirtual())
391 continue;
392
393 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
394
395 CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(BaseDecl);
396 if (!CanPlaceFieldSubobjectAtOffset(BaseDecl, Class, BaseOffset))
397 return false;
398 }
399
400 if (RD == Class) {
401 // This is the most derived class, traverse virtual bases as well.
402 for (const CXXBaseSpecifier &Base : RD->vbases()) {
403 const CXXRecordDecl *VBaseDecl = Base.getType()->getAsCXXRecordDecl();
404
405 CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBaseDecl);
406 if (!CanPlaceFieldSubobjectAtOffset(VBaseDecl, Class, VBaseOffset))
407 return false;
408 }
409 }
410
411 // Traverse all member variables.
412 unsigned FieldNo = 0;
413 for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
414 I != E; ++I, ++FieldNo) {
415 if (I->isBitField())
416 continue;
417
418 CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
419
420 if (!CanPlaceFieldSubobjectAtOffset(*I, FieldOffset))
421 return false;
422 }
423
424 return true;
425}
426
427bool
428EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD,
429 CharUnits Offset) const {
430 // We don't have to keep looking past the maximum offset that's known to
431 // contain an empty class.
432 if (!AnyEmptySubobjectsBeyondOffset(Offset))
433 return true;
434
435 QualType T = FD->getType();
436 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
437 return CanPlaceFieldSubobjectAtOffset(RD, RD, Offset);
438
439 // If we have an array type we need to look at every element.
440 if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
441 QualType ElemTy = Context.getBaseElementType(AT);
442 const RecordType *RT = ElemTy->getAs<RecordType>();
443 if (!RT)
444 return true;
445
446 const CXXRecordDecl *RD = RT->getAsCXXRecordDecl();
447 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
448
449 uint64_t NumElements = Context.getConstantArrayElementCount(AT);
450 CharUnits ElementOffset = Offset;
451 for (uint64_t I = 0; I != NumElements; ++I) {
452 // We don't have to keep looking past the maximum offset that's known to
453 // contain an empty class.
454 if (!AnyEmptySubobjectsBeyondOffset(ElementOffset))
455 return true;
456
457 if (!CanPlaceFieldSubobjectAtOffset(RD, RD, ElementOffset))
458 return false;
459
460 ElementOffset += Layout.getSize();
461 }
462 }
463
464 return true;
465}
466
467bool
468EmptySubobjectMap::CanPlaceFieldAtOffset(const FieldDecl *FD,
469 CharUnits Offset) {
470 if (!CanPlaceFieldSubobjectAtOffset(FD, Offset))
471 return false;
472
473 // We are able to place the member variable at this offset.
474 // Make sure to update the empty base subobject map.
475 UpdateEmptyFieldSubobjects(FD, Offset);
476 return true;
477}
478
479void EmptySubobjectMap::UpdateEmptyFieldSubobjects(const CXXRecordDecl *RD,
480 const CXXRecordDecl *Class,
481 CharUnits Offset) {
482 // We know that the only empty subobjects that can conflict with empty
483 // field subobjects are subobjects of empty bases that can be placed at offset
484 // zero. Because of this, we only need to keep track of empty field
485 // subobjects with offsets less than the size of the largest empty
486 // subobject for our class.
487 if (Offset >= SizeOfLargestEmptySubobject)
488 return;
489
490 AddSubobjectAtOffset(RD, Offset);
491
492 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
493
494 // Traverse all non-virtual bases.
495 for (const CXXBaseSpecifier &Base : RD->bases()) {
496 if (Base.isVirtual())
497 continue;
498
499 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
500
501 CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(BaseDecl);
502 UpdateEmptyFieldSubobjects(BaseDecl, Class, BaseOffset);
503 }
504
505 if (RD == Class) {
506 // This is the most derived class, traverse virtual bases as well.
507 for (const CXXBaseSpecifier &Base : RD->vbases()) {
508 const CXXRecordDecl *VBaseDecl = Base.getType()->getAsCXXRecordDecl();
509
510 CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBaseDecl);
511 UpdateEmptyFieldSubobjects(VBaseDecl, Class, VBaseOffset);
512 }
513 }
514
515 // Traverse all member variables.
516 unsigned FieldNo = 0;
517 for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
518 I != E; ++I, ++FieldNo) {
519 if (I->isBitField())
520 continue;
521
522 CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
523
524 UpdateEmptyFieldSubobjects(*I, FieldOffset);
525 }
526}
527
528void EmptySubobjectMap::UpdateEmptyFieldSubobjects(const FieldDecl *FD,
529 CharUnits Offset) {
530 QualType T = FD->getType();
531 if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl()) {
532 UpdateEmptyFieldSubobjects(RD, RD, Offset);
533 return;
534 }
535
536 // If we have an array type we need to update every element.
537 if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
538 QualType ElemTy = Context.getBaseElementType(AT);
539 const RecordType *RT = ElemTy->getAs<RecordType>();
540 if (!RT)
541 return;
542
543 const CXXRecordDecl *RD = RT->getAsCXXRecordDecl();
544 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
545
546 uint64_t NumElements = Context.getConstantArrayElementCount(AT);
547 CharUnits ElementOffset = Offset;
548
549 for (uint64_t I = 0; I != NumElements; ++I) {
550 // We know that the only empty subobjects that can conflict with empty
551 // field subobjects are subobjects of empty bases that can be placed at
552 // offset zero. Because of this, we only need to keep track of empty field
553 // subobjects with offsets less than the size of the largest empty
554 // subobject for our class.
555 if (ElementOffset >= SizeOfLargestEmptySubobject)
556 return;
557
558 UpdateEmptyFieldSubobjects(RD, RD, ElementOffset);
559 ElementOffset += Layout.getSize();
560 }
561 }
562}
563
564typedef llvm::SmallPtrSet<const CXXRecordDecl*, 4> ClassSetTy;
565
566class ItaniumRecordLayoutBuilder {
567protected:
568 // FIXME: Remove this and make the appropriate fields public.
569 friend class clang::ASTContext;
570
571 const ASTContext &Context;
572
573 EmptySubobjectMap *EmptySubobjects;
574
575 /// Size - The current size of the record layout.
576 uint64_t Size;
577
578 /// Alignment - The current alignment of the record layout.
579 CharUnits Alignment;
580
581 /// The alignment if attribute packed is not used.
582 CharUnits UnpackedAlignment;
583
584 /// \brief The maximum of the alignments of top-level members.
585 CharUnits UnadjustedAlignment;
586
587 SmallVector<uint64_t, 16> FieldOffsets;
588
589 /// Whether the external AST source has provided a layout for this
590 /// record.
591 unsigned UseExternalLayout : 1;
592
593 /// Whether we need to infer alignment, even when we have an
594 /// externally-provided layout.
595 unsigned InferAlignment : 1;
596
597 /// Packed - Whether the record is packed or not.
598 unsigned Packed : 1;
599
600 unsigned IsUnion : 1;
601
602 unsigned IsMac68kAlign : 1;
603
604 unsigned IsMsStruct : 1;
605
606 /// UnfilledBitsInLastUnit - If the last field laid out was a bitfield,
607 /// this contains the number of bits in the last unit that can be used for
608 /// an adjacent bitfield if necessary. The unit in question is usually
609 /// a byte, but larger units are used if IsMsStruct.
610 unsigned char UnfilledBitsInLastUnit;
611 /// LastBitfieldTypeSize - If IsMsStruct, represents the size of the type
612 /// of the previous field if it was a bitfield.
613 unsigned char LastBitfieldTypeSize;
614
615 /// MaxFieldAlignment - The maximum allowed field alignment. This is set by
616 /// #pragma pack.
617 CharUnits MaxFieldAlignment;
618
619 /// DataSize - The data size of the record being laid out.
620 uint64_t DataSize;
621
622 CharUnits NonVirtualSize;
623 CharUnits NonVirtualAlignment;
624
625 /// PrimaryBase - the primary base class (if one exists) of the class
626 /// we're laying out.
627 const CXXRecordDecl *PrimaryBase;
628
629 /// PrimaryBaseIsVirtual - Whether the primary base of the class we're laying
630 /// out is virtual.
631 bool PrimaryBaseIsVirtual;
632
633 /// HasOwnVFPtr - Whether the class provides its own vtable/vftbl
634 /// pointer, as opposed to inheriting one from a primary base class.
635 bool HasOwnVFPtr;
636
637 /// the flag of field offset changing due to packed attribute.
638 bool HasPackedField;
639
640 typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
641
642 /// Bases - base classes and their offsets in the record.
643 BaseOffsetsMapTy Bases;
644
645 // VBases - virtual base classes and their offsets in the record.
646 ASTRecordLayout::VBaseOffsetsMapTy VBases;
647
648 /// IndirectPrimaryBases - Virtual base classes, direct or indirect, that are
649 /// primary base classes for some other direct or indirect base class.
650 CXXIndirectPrimaryBaseSet IndirectPrimaryBases;
651
652 /// FirstNearlyEmptyVBase - The first nearly empty virtual base class in
653 /// inheritance graph order. Used for determining the primary base class.
654 const CXXRecordDecl *FirstNearlyEmptyVBase;
655
656 /// VisitedVirtualBases - A set of all the visited virtual bases, used to
657 /// avoid visiting virtual bases more than once.
658 llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBases;
659
660 /// Valid if UseExternalLayout is true.
661 ExternalLayout External;
662
663 ItaniumRecordLayoutBuilder(const ASTContext &Context,
664 EmptySubobjectMap *EmptySubobjects)
665 : Context(Context), EmptySubobjects(EmptySubobjects), Size(0),
666 Alignment(CharUnits::One()), UnpackedAlignment(CharUnits::One()),
667 UnadjustedAlignment(CharUnits::One()),
668 UseExternalLayout(false), InferAlignment(false), Packed(false),
669 IsUnion(false), IsMac68kAlign(false), IsMsStruct(false),
670 UnfilledBitsInLastUnit(0), LastBitfieldTypeSize(0),
671 MaxFieldAlignment(CharUnits::Zero()), DataSize(0),
672 NonVirtualSize(CharUnits::Zero()),
673 NonVirtualAlignment(CharUnits::One()), PrimaryBase(nullptr),
674 PrimaryBaseIsVirtual(false), HasOwnVFPtr(false),
675 HasPackedField(false), FirstNearlyEmptyVBase(nullptr) {}
676
677 void Layout(const RecordDecl *D);
678 void Layout(const CXXRecordDecl *D);
679 void Layout(const ObjCInterfaceDecl *D);
680
681 void LayoutFields(const RecordDecl *D);
682 void LayoutField(const FieldDecl *D, bool InsertExtraPadding);
683 void LayoutWideBitField(uint64_t FieldSize, uint64_t TypeSize,
684 bool FieldPacked, const FieldDecl *D);
685 void LayoutBitField(const FieldDecl *D);
686
687 TargetCXXABI getCXXABI() const {
688 return Context.getTargetInfo().getCXXABI();
689 }
690
691 /// BaseSubobjectInfoAllocator - Allocator for BaseSubobjectInfo objects.
692 llvm::SpecificBumpPtrAllocator<BaseSubobjectInfo> BaseSubobjectInfoAllocator;
693
694 typedef llvm::DenseMap<const CXXRecordDecl *, BaseSubobjectInfo *>
695 BaseSubobjectInfoMapTy;
696
697 /// VirtualBaseInfo - Map from all the (direct or indirect) virtual bases
698 /// of the class we're laying out to their base subobject info.
699 BaseSubobjectInfoMapTy VirtualBaseInfo;
700
701 /// NonVirtualBaseInfo - Map from all the direct non-virtual bases of the
702 /// class we're laying out to their base subobject info.
703 BaseSubobjectInfoMapTy NonVirtualBaseInfo;
704
705 /// ComputeBaseSubobjectInfo - Compute the base subobject information for the
706 /// bases of the given class.
707 void ComputeBaseSubobjectInfo(const CXXRecordDecl *RD);
708
709 /// ComputeBaseSubobjectInfo - Compute the base subobject information for a
710 /// single class and all of its base classes.
711 BaseSubobjectInfo *ComputeBaseSubobjectInfo(const CXXRecordDecl *RD,
712 bool IsVirtual,
713 BaseSubobjectInfo *Derived);
714
715 /// DeterminePrimaryBase - Determine the primary base of the given class.
716 void DeterminePrimaryBase(const CXXRecordDecl *RD);
717
718 void SelectPrimaryVBase(const CXXRecordDecl *RD);
719
720 void EnsureVTablePointerAlignment(CharUnits UnpackedBaseAlign);
721
722 /// LayoutNonVirtualBases - Determines the primary base class (if any) and
723 /// lays it out. Will then proceed to lay out all non-virtual base clasess.
724 void LayoutNonVirtualBases(const CXXRecordDecl *RD);
725
726 /// LayoutNonVirtualBase - Lays out a single non-virtual base.
727 void LayoutNonVirtualBase(const BaseSubobjectInfo *Base);
728
729 void AddPrimaryVirtualBaseOffsets(const BaseSubobjectInfo *Info,
730 CharUnits Offset);
731
732 /// LayoutVirtualBases - Lays out all the virtual bases.
733 void LayoutVirtualBases(const CXXRecordDecl *RD,
734 const CXXRecordDecl *MostDerivedClass);
735
736 /// LayoutVirtualBase - Lays out a single virtual base.
737 void LayoutVirtualBase(const BaseSubobjectInfo *Base);
738
739 /// LayoutBase - Will lay out a base and return the offset where it was
740 /// placed, in chars.
741 CharUnits LayoutBase(const BaseSubobjectInfo *Base);
742
743 /// InitializeLayout - Initialize record layout for the given record decl.
744 void InitializeLayout(const Decl *D);
745
746 /// FinishLayout - Finalize record layout. Adjust record size based on the
747 /// alignment.
748 void FinishLayout(const NamedDecl *D);
749
750 void UpdateAlignment(CharUnits NewAlignment, CharUnits UnpackedNewAlignment);
751 void UpdateAlignment(CharUnits NewAlignment) {
752 UpdateAlignment(NewAlignment, NewAlignment);
753 }
754
755 /// Retrieve the externally-supplied field offset for the given
756 /// field.
757 ///
758 /// \param Field The field whose offset is being queried.
759 /// \param ComputedOffset The offset that we've computed for this field.
760 uint64_t updateExternalFieldOffset(const FieldDecl *Field,
761 uint64_t ComputedOffset);
762
763 void CheckFieldPadding(uint64_t Offset, uint64_t UnpaddedOffset,
764 uint64_t UnpackedOffset, unsigned UnpackedAlign,
765 bool isPacked, const FieldDecl *D);
766
767 DiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID);
768
769 CharUnits getSize() const {
770 assert(Size % Context.getCharWidth() == 0)((Size % Context.getCharWidth() == 0) ? static_cast<void>
(0) : __assert_fail ("Size % Context.getCharWidth() == 0", "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 770, __PRETTY_FUNCTION__))
;
771 return Context.toCharUnitsFromBits(Size);
772 }
773 uint64_t getSizeInBits() const { return Size; }
774
775 void setSize(CharUnits NewSize) { Size = Context.toBits(NewSize); }
776 void setSize(uint64_t NewSize) { Size = NewSize; }
777
778 CharUnits getAligment() const { return Alignment; }
779
780 CharUnits getDataSize() const {
781 assert(DataSize % Context.getCharWidth() == 0)((DataSize % Context.getCharWidth() == 0) ? static_cast<void
> (0) : __assert_fail ("DataSize % Context.getCharWidth() == 0"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 781, __PRETTY_FUNCTION__))
;
782 return Context.toCharUnitsFromBits(DataSize);
783 }
784 uint64_t getDataSizeInBits() const { return DataSize; }
785
786 void setDataSize(CharUnits NewSize) { DataSize = Context.toBits(NewSize); }
787 void setDataSize(uint64_t NewSize) { DataSize = NewSize; }
788
789 ItaniumRecordLayoutBuilder(const ItaniumRecordLayoutBuilder &) = delete;
790 void operator=(const ItaniumRecordLayoutBuilder &) = delete;
791};
792} // end anonymous namespace
793
794void ItaniumRecordLayoutBuilder::SelectPrimaryVBase(const CXXRecordDecl *RD) {
795 for (const auto &I : RD->bases()) {
796 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 797, __PRETTY_FUNCTION__))
797 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 797, __PRETTY_FUNCTION__))
;
798
799 const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
800
801 // Check if this is a nearly empty virtual base.
802 if (I.isVirtual() && Context.isNearlyEmpty(Base)) {
803 // If it's not an indirect primary base, then we've found our primary
804 // base.
805 if (!IndirectPrimaryBases.count(Base)) {
806 PrimaryBase = Base;
807 PrimaryBaseIsVirtual = true;
808 return;
809 }
810
811 // Is this the first nearly empty virtual base?
812 if (!FirstNearlyEmptyVBase)
813 FirstNearlyEmptyVBase = Base;
814 }
815
816 SelectPrimaryVBase(Base);
817 if (PrimaryBase)
818 return;
819 }
820}
821
822/// DeterminePrimaryBase - Determine the primary base of the given class.
823void ItaniumRecordLayoutBuilder::DeterminePrimaryBase(const CXXRecordDecl *RD) {
824 // If the class isn't dynamic, it won't have a primary base.
825 if (!RD->isDynamicClass())
826 return;
827
828 // Compute all the primary virtual bases for all of our direct and
829 // indirect bases, and record all their primary virtual base classes.
830 RD->getIndirectPrimaryBases(IndirectPrimaryBases);
831
832 // If the record has a dynamic base class, attempt to choose a primary base
833 // class. It is the first (in direct base class order) non-virtual dynamic
834 // base class, if one exists.
835 for (const auto &I : RD->bases()) {
836 // Ignore virtual bases.
837 if (I.isVirtual())
838 continue;
839
840 const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
841
842 if (Base->isDynamicClass()) {
843 // We found it.
844 PrimaryBase = Base;
845 PrimaryBaseIsVirtual = false;
846 return;
847 }
848 }
849
850 // Under the Itanium ABI, if there is no non-virtual primary base class,
851 // try to compute the primary virtual base. The primary virtual base is
852 // the first nearly empty virtual base that is not an indirect primary
853 // virtual base class, if one exists.
854 if (RD->getNumVBases() != 0) {
855 SelectPrimaryVBase(RD);
856 if (PrimaryBase)
857 return;
858 }
859
860 // Otherwise, it is the first indirect primary base class, if one exists.
861 if (FirstNearlyEmptyVBase) {
862 PrimaryBase = FirstNearlyEmptyVBase;
863 PrimaryBaseIsVirtual = true;
864 return;
865 }
866
867 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 867, __PRETTY_FUNCTION__))
;
868}
869
870BaseSubobjectInfo *ItaniumRecordLayoutBuilder::ComputeBaseSubobjectInfo(
871 const CXXRecordDecl *RD, bool IsVirtual, BaseSubobjectInfo *Derived) {
872 BaseSubobjectInfo *Info;
873
874 if (IsVirtual) {
875 // Check if we already have info about this virtual base.
876 BaseSubobjectInfo *&InfoSlot = VirtualBaseInfo[RD];
877 if (InfoSlot) {
878 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 878, __PRETTY_FUNCTION__))
;
879 return InfoSlot;
880 }
881
882 // We don't, create it.
883 InfoSlot = new (BaseSubobjectInfoAllocator.Allocate()) BaseSubobjectInfo;
884 Info = InfoSlot;
885 } else {
886 Info = new (BaseSubobjectInfoAllocator.Allocate()) BaseSubobjectInfo;
887 }
888
889 Info->Class = RD;
890 Info->IsVirtual = IsVirtual;
891 Info->Derived = nullptr;
892 Info->PrimaryVirtualBaseInfo = nullptr;
893
894 const CXXRecordDecl *PrimaryVirtualBase = nullptr;
895 BaseSubobjectInfo *PrimaryVirtualBaseInfo = nullptr;
896
897 // Check if this base has a primary virtual base.
898 if (RD->getNumVBases()) {
899 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
900 if (Layout.isPrimaryBaseVirtual()) {
901 // This base does have a primary virtual base.
902 PrimaryVirtualBase = Layout.getPrimaryBase();
903 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 903, __PRETTY_FUNCTION__))
;
904
905 // Now check if we have base subobject info about this primary base.
906 PrimaryVirtualBaseInfo = VirtualBaseInfo.lookup(PrimaryVirtualBase);
907
908 if (PrimaryVirtualBaseInfo) {
909 if (PrimaryVirtualBaseInfo->Derived) {
910 // We did have info about this primary base, and it turns out that it
911 // has already been claimed as a primary virtual base for another
912 // base.
913 PrimaryVirtualBase = nullptr;
914 } else {
915 // We can claim this base as our primary base.
916 Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
917 PrimaryVirtualBaseInfo->Derived = Info;
918 }
919 }
920 }
921 }
922
923 // Now go through all direct bases.
924 for (const auto &I : RD->bases()) {
925 bool IsVirtual = I.isVirtual();
926
927 const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
928
929 Info->Bases.push_back(ComputeBaseSubobjectInfo(BaseDecl, IsVirtual, Info));
930 }
931
932 if (PrimaryVirtualBase && !PrimaryVirtualBaseInfo) {
933 // Traversing the bases must have created the base info for our primary
934 // virtual base.
935 PrimaryVirtualBaseInfo = VirtualBaseInfo.lookup(PrimaryVirtualBase);
936 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 937, __PRETTY_FUNCTION__))
937 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 937, __PRETTY_FUNCTION__))
;
938
939 // Claim the primary virtual base as our primary virtual base.
940 Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
941 PrimaryVirtualBaseInfo->Derived = Info;
942 }
943
944 return Info;
945}
946
947void ItaniumRecordLayoutBuilder::ComputeBaseSubobjectInfo(
948 const CXXRecordDecl *RD) {
949 for (const auto &I : RD->bases()) {
950 bool IsVirtual = I.isVirtual();
951
952 const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
953
954 // Compute the base subobject info for this base.
955 BaseSubobjectInfo *Info = ComputeBaseSubobjectInfo(BaseDecl, IsVirtual,
956 nullptr);
957
958 if (IsVirtual) {
959 // ComputeBaseInfo has already added this base for us.
960 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 961, __PRETTY_FUNCTION__))
961 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 961, __PRETTY_FUNCTION__))
;
962 } else {
963 // Add the base info to the map of non-virtual bases.
964 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 965, __PRETTY_FUNCTION__))
965 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 965, __PRETTY_FUNCTION__))
;
966 NonVirtualBaseInfo.insert(std::make_pair(BaseDecl, Info));
967 }
968 }
969}
970
971void ItaniumRecordLayoutBuilder::EnsureVTablePointerAlignment(
972 CharUnits UnpackedBaseAlign) {
973 CharUnits BaseAlign = Packed ? CharUnits::One() : UnpackedBaseAlign;
974
975 // The maximum field alignment overrides base align.
976 if (!MaxFieldAlignment.isZero()) {
977 BaseAlign = std::min(BaseAlign, MaxFieldAlignment);
978 UnpackedBaseAlign = std::min(UnpackedBaseAlign, MaxFieldAlignment);
979 }
980
981 // Round up the current record size to pointer alignment.
982 setSize(getSize().alignTo(BaseAlign));
983 setDataSize(getSize());
984
985 // Update the alignment.
986 UpdateAlignment(BaseAlign, UnpackedBaseAlign);
987}
988
989void ItaniumRecordLayoutBuilder::LayoutNonVirtualBases(
990 const CXXRecordDecl *RD) {
991 // Then, determine the primary base class.
992 DeterminePrimaryBase(RD);
993
994 // Compute base subobject info.
995 ComputeBaseSubobjectInfo(RD);
996
997 // If we have a primary base class, lay it out.
998 if (PrimaryBase) {
999 if (PrimaryBaseIsVirtual) {
1000 // If the primary virtual base was a primary virtual base of some other
1001 // base class we'll have to steal it.
1002 BaseSubobjectInfo *PrimaryBaseInfo = VirtualBaseInfo.lookup(PrimaryBase);
1003 PrimaryBaseInfo->Derived = nullptr;
1004
1005 // We have a virtual primary base, insert it as an indirect primary base.
1006 IndirectPrimaryBases.insert(PrimaryBase);
1007
1008 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1009, __PRETTY_FUNCTION__))
1009 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1009, __PRETTY_FUNCTION__))
;
1010 VisitedVirtualBases.insert(PrimaryBase);
1011
1012 LayoutVirtualBase(PrimaryBaseInfo);
1013 } else {
1014 BaseSubobjectInfo *PrimaryBaseInfo =
1015 NonVirtualBaseInfo.lookup(PrimaryBase);
1016 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1017, __PRETTY_FUNCTION__))
1017 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1017, __PRETTY_FUNCTION__))
;
1018
1019 LayoutNonVirtualBase(PrimaryBaseInfo);
1020 }
1021
1022 // If this class needs a vtable/vf-table and didn't get one from a
1023 // primary base, add it in now.
1024 } else if (RD->isDynamicClass()) {
1025 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1025, __PRETTY_FUNCTION__))
;
1026 CharUnits PtrWidth =
1027 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
1028 CharUnits PtrAlign =
1029 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(0));
1030 EnsureVTablePointerAlignment(PtrAlign);
1031 HasOwnVFPtr = true;
1032 setSize(getSize() + PtrWidth);
1033 setDataSize(getSize());
1034 }
1035
1036 // Now lay out the non-virtual bases.
1037 for (const auto &I : RD->bases()) {
1038
1039 // Ignore virtual bases.
1040 if (I.isVirtual())
1041 continue;
1042
1043 const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();
1044
1045 // Skip the primary base, because we've already laid it out. The
1046 // !PrimaryBaseIsVirtual check is required because we might have a
1047 // non-virtual base of the same type as a primary virtual base.
1048 if (BaseDecl == PrimaryBase && !PrimaryBaseIsVirtual)
1049 continue;
1050
1051 // Lay out the base.
1052 BaseSubobjectInfo *BaseInfo = NonVirtualBaseInfo.lookup(BaseDecl);
1053 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1053, __PRETTY_FUNCTION__))
;
1054
1055 LayoutNonVirtualBase(BaseInfo);
1056 }
1057}
1058
1059void ItaniumRecordLayoutBuilder::LayoutNonVirtualBase(
1060 const BaseSubobjectInfo *Base) {
1061 // Layout the base.
1062 CharUnits Offset = LayoutBase(Base);
1063
1064 // Add its base class offset.
1065 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1065, __PRETTY_FUNCTION__))
;
1066 Bases.insert(std::make_pair(Base->Class, Offset));
1067
1068 AddPrimaryVirtualBaseOffsets(Base, Offset);
1069}
1070
1071void ItaniumRecordLayoutBuilder::AddPrimaryVirtualBaseOffsets(
1072 const BaseSubobjectInfo *Info, CharUnits Offset) {
1073 // This base isn't interesting, it has no virtual bases.
1074 if (!Info->Class->getNumVBases())
1075 return;
1076
1077 // First, check if we have a virtual primary base to add offsets for.
1078 if (Info->PrimaryVirtualBaseInfo) {
1079 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1080, __PRETTY_FUNCTION__))
1080 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1080, __PRETTY_FUNCTION__))
;
1081 if (Info->PrimaryVirtualBaseInfo->Derived == Info) {
1082 // Add the offset.
1083 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1084, __PRETTY_FUNCTION__))
1084 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1084, __PRETTY_FUNCTION__))
;
1085 VBases.insert(std::make_pair(Info->PrimaryVirtualBaseInfo->Class,
1086 ASTRecordLayout::VBaseInfo(Offset, false)));
1087
1088 // Traverse the primary virtual base.
1089 AddPrimaryVirtualBaseOffsets(Info->PrimaryVirtualBaseInfo, Offset);
1090 }
1091 }
1092
1093 // Now go through all direct non-virtual bases.
1094 const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
1095 for (const BaseSubobjectInfo *Base : Info->Bases) {
1096 if (Base->IsVirtual)
1097 continue;
1098
1099 CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
1100 AddPrimaryVirtualBaseOffsets(Base, BaseOffset);
1101 }
1102}
1103
1104void ItaniumRecordLayoutBuilder::LayoutVirtualBases(
1105 const CXXRecordDecl *RD, const CXXRecordDecl *MostDerivedClass) {
1106 const CXXRecordDecl *PrimaryBase;
1107 bool PrimaryBaseIsVirtual;
1108
1109 if (MostDerivedClass == RD) {
17
Taking true branch
1110 PrimaryBase = this->PrimaryBase;
1111 PrimaryBaseIsVirtual = this->PrimaryBaseIsVirtual;
1112 } else {
1113 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
1114 PrimaryBase = Layout.getPrimaryBase();
1115 PrimaryBaseIsVirtual = Layout.isPrimaryBaseVirtual();
1116 }
1117
1118 for (const CXXBaseSpecifier &Base : RD->bases()) {
18
Assuming '__begin1' is not equal to '__end1'
1119 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1120, __PRETTY_FUNCTION__))
19
Assuming the condition is true
20
'?' condition is true
1120 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1120, __PRETTY_FUNCTION__))
;
1121
1122 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
21
'BaseDecl' initialized here
1123
1124 if (Base.isVirtual()) {
22
Assuming the condition is true
23
Taking true branch
1125 if (PrimaryBase != BaseDecl || !PrimaryBaseIsVirtual) {
24
Assuming 'PrimaryBase' is equal to 'BaseDecl'
25
Assuming pointer value is null
26
Assuming 'PrimaryBaseIsVirtual' is not equal to 0
27
Taking false branch
1126 bool IndirectPrimaryBase = IndirectPrimaryBases.count(BaseDecl);
1127
1128 // Only lay out the virtual base if it's not an indirect primary base.
1129 if (!IndirectPrimaryBase) {
1130 // Only visit virtual bases once.
1131 if (!VisitedVirtualBases.insert(BaseDecl).second)
1132 continue;
1133
1134 const BaseSubobjectInfo *BaseInfo = VirtualBaseInfo.lookup(BaseDecl);
1135 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1135, __PRETTY_FUNCTION__))
;
1136 LayoutVirtualBase(BaseInfo);
1137 }
1138 }
1139 }
1140
1141 if (!BaseDecl->getNumVBases()) {
28
Called C++ object pointer is null
1142 // This base isn't interesting since it doesn't have any virtual bases.
1143 continue;
1144 }
1145
1146 LayoutVirtualBases(BaseDecl, MostDerivedClass);
1147 }
1148}
1149
1150void ItaniumRecordLayoutBuilder::LayoutVirtualBase(
1151 const BaseSubobjectInfo *Base) {
1152 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1152, __PRETTY_FUNCTION__))
;
1153
1154 // Layout the base.
1155 CharUnits Offset = LayoutBase(Base);
1156
1157 // Add its base class offset.
1158 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1158, __PRETTY_FUNCTION__))
;
1159 VBases.insert(std::make_pair(Base->Class,
1160 ASTRecordLayout::VBaseInfo(Offset, false)));
1161
1162 AddPrimaryVirtualBaseOffsets(Base, Offset);
1163}
1164
1165CharUnits
1166ItaniumRecordLayoutBuilder::LayoutBase(const BaseSubobjectInfo *Base) {
1167 const ASTRecordLayout &Layout = Context.getASTRecordLayout(Base->Class);
1168
1169
1170 CharUnits Offset;
1171
1172 // Query the external layout to see if it provides an offset.
1173 bool HasExternalLayout = false;
1174 if (UseExternalLayout) {
1175 if (Base->IsVirtual)
1176 HasExternalLayout = External.getExternalNVBaseOffset(Base->Class, Offset);
1177 else
1178 HasExternalLayout = External.getExternalVBaseOffset(Base->Class, Offset);
1179 }
1180
1181 // Clang <= 6 incorrectly applied the 'packed' attribute to base classes.
1182 // Per GCC's documentation, it only applies to non-static data members.
1183 CharUnits UnpackedBaseAlign = Layout.getNonVirtualAlignment();
1184 CharUnits BaseAlign =
1185 (Packed && ((Context.getLangOpts().getClangABICompat() <=
1186 LangOptions::ClangABI::Ver6) ||
1187 Context.getTargetInfo().getTriple().isPS4()))
1188 ? CharUnits::One()
1189 : UnpackedBaseAlign;
1190
1191 // If we have an empty base class, try to place it at offset 0.
1192 if (Base->Class->isEmpty() &&
1193 (!HasExternalLayout || Offset == CharUnits::Zero()) &&
1194 EmptySubobjects->CanPlaceBaseAtOffset(Base, CharUnits::Zero())) {
1195 setSize(std::max(getSize(), Layout.getSize()));
1196 UpdateAlignment(BaseAlign, UnpackedBaseAlign);
1197
1198 return CharUnits::Zero();
1199 }
1200
1201 // The maximum field alignment overrides base align.
1202 if (!MaxFieldAlignment.isZero()) {
1203 BaseAlign = std::min(BaseAlign, MaxFieldAlignment);
1204 UnpackedBaseAlign = std::min(UnpackedBaseAlign, MaxFieldAlignment);
1205 }
1206
1207 if (!HasExternalLayout) {
1208 // Round up the current record size to the base's alignment boundary.
1209 Offset = getDataSize().alignTo(BaseAlign);
1210
1211 // Try to place the base.
1212 while (!EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset))
1213 Offset += BaseAlign;
1214 } else {
1215 bool Allowed = EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset);
1216 (void)Allowed;
1217 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1217, __PRETTY_FUNCTION__))
;
1218
1219 if (InferAlignment && Offset < getDataSize().alignTo(BaseAlign)) {
1220 // The externally-supplied base offset is before the base offset we
1221 // computed. Assume that the structure is packed.
1222 Alignment = CharUnits::One();
1223 InferAlignment = false;
1224 }
1225 }
1226
1227 if (!Base->Class->isEmpty()) {
1228 // Update the data size.
1229 setDataSize(Offset + Layout.getNonVirtualSize());
1230
1231 setSize(std::max(getSize(), getDataSize()));
1232 } else
1233 setSize(std::max(getSize(), Offset + Layout.getSize()));
1234
1235 // Remember max struct/class alignment.
1236 UpdateAlignment(BaseAlign, UnpackedBaseAlign);
1237
1238 return Offset;
1239}
1240
1241void ItaniumRecordLayoutBuilder::InitializeLayout(const Decl *D) {
1242 if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
1243 IsUnion = RD->isUnion();
1244 IsMsStruct = RD->isMsStruct(Context);
1245 }
1246
1247 Packed = D->hasAttr<PackedAttr>();
1248
1249 // Honor the default struct packing maximum alignment flag.
1250 if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct) {
1251 MaxFieldAlignment = CharUnits::fromQuantity(DefaultMaxFieldAlignment);
1252 }
1253
1254 // mac68k alignment supersedes maximum field alignment and attribute aligned,
1255 // and forces all structures to have 2-byte alignment. The IBM docs on it
1256 // allude to additional (more complicated) semantics, especially with regard
1257 // to bit-fields, but gcc appears not to follow that.
1258 if (D->hasAttr<AlignMac68kAttr>()) {
1259 IsMac68kAlign = true;
1260 MaxFieldAlignment = CharUnits::fromQuantity(2);
1261 Alignment = CharUnits::fromQuantity(2);
1262 } else {
1263 if (const MaxFieldAlignmentAttr *MFAA = D->getAttr<MaxFieldAlignmentAttr>())
1264 MaxFieldAlignment = Context.toCharUnitsFromBits(MFAA->getAlignment());
1265
1266 if (unsigned MaxAlign = D->getMaxAlignment())
1267 UpdateAlignment(Context.toCharUnitsFromBits(MaxAlign));
1268 }
1269
1270 // If there is an external AST source, ask it for the various offsets.
1271 if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
1272 if (ExternalASTSource *Source = Context.getExternalSource()) {
1273 UseExternalLayout = Source->layoutRecordType(
1274 RD, External.Size, External.Align, External.FieldOffsets,
1275 External.BaseOffsets, External.VirtualBaseOffsets);
1276
1277 // Update based on external alignment.
1278 if (UseExternalLayout) {
1279 if (External.Align > 0) {
1280 Alignment = Context.toCharUnitsFromBits(External.Align);
1281 } else {
1282 // The external source didn't have alignment information; infer it.
1283 InferAlignment = true;
1284 }
1285 }
1286 }
1287}
1288
1289void ItaniumRecordLayoutBuilder::Layout(const RecordDecl *D) {
1290 InitializeLayout(D);
1291 LayoutFields(D);
1292
1293 // Finally, round the size of the total struct up to the alignment of the
1294 // struct itself.
1295 FinishLayout(D);
1296}
1297
1298void ItaniumRecordLayoutBuilder::Layout(const CXXRecordDecl *RD) {
1299 InitializeLayout(RD);
1300
1301 // Lay out the vtable and the non-virtual bases.
1302 LayoutNonVirtualBases(RD);
1303
1304 LayoutFields(RD);
1305
1306 NonVirtualSize = Context.toCharUnitsFromBits(
1307 llvm::alignTo(getSizeInBits(), Context.getTargetInfo().getCharAlign()));
1308 NonVirtualAlignment = Alignment;
1309
1310 // Lay out the virtual bases and add the primary virtual base offsets.
1311 LayoutVirtualBases(RD, RD);
16
Calling 'ItaniumRecordLayoutBuilder::LayoutVirtualBases'
1312
1313 // Finally, round the size of the total struct up to the alignment
1314 // of the struct itself.
1315 FinishLayout(RD);
1316
1317#ifndef NDEBUG
1318 // Check that we have base offsets for all bases.
1319 for (const CXXBaseSpecifier &Base : RD->bases()) {
1320 if (Base.isVirtual())
1321 continue;
1322
1323 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1324
1325 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1325, __PRETTY_FUNCTION__))
;
1326 }
1327
1328 // And all virtual bases.
1329 for (const CXXBaseSpecifier &Base : RD->vbases()) {
1330 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
1331
1332 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1332, __PRETTY_FUNCTION__))
;
1333 }
1334#endif
1335}
1336
1337void ItaniumRecordLayoutBuilder::Layout(const ObjCInterfaceDecl *D) {
1338 if (ObjCInterfaceDecl *SD = D->getSuperClass()) {
1339 const ASTRecordLayout &SL = Context.getASTObjCInterfaceLayout(SD);
1340
1341 UpdateAlignment(SL.getAlignment());
1342
1343 // We start laying out ivars not at the end of the superclass
1344 // structure, but at the next byte following the last field.
1345 setSize(SL.getDataSize());
1346 setDataSize(getSize());
1347 }
1348
1349 InitializeLayout(D);
1350 // Layout each ivar sequentially.
1351 for (const ObjCIvarDecl *IVD = D->all_declared_ivar_begin(); IVD;
1352 IVD = IVD->getNextIvar())
1353 LayoutField(IVD, false);
1354
1355 // Finally, round the size of the total struct up to the alignment of the
1356 // struct itself.
1357 FinishLayout(D);
1358}
1359
1360void ItaniumRecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
1361 // Layout each field, for now, just sequentially, respecting alignment. In
1362 // the future, this will need to be tweakable by targets.
1363 bool InsertExtraPadding = D->mayInsertExtraPadding(/*EmitRemark=*/true);
1364 bool HasFlexibleArrayMember = D->hasFlexibleArrayMember();
1365 for (auto I = D->field_begin(), End = D->field_end(); I != End; ++I) {
1366 auto Next(I);
1367 ++Next;
1368 LayoutField(*I,
1369 InsertExtraPadding && (Next != End || !HasFlexibleArrayMember));
1370 }
1371}
1372
1373// Rounds the specified size to have it a multiple of the char size.
1374static uint64_t
1375roundUpSizeToCharAlignment(uint64_t Size,
1376 const ASTContext &Context) {
1377 uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
1378 return llvm::alignTo(Size, CharAlignment);
1379}
1380
1381void ItaniumRecordLayoutBuilder::LayoutWideBitField(uint64_t FieldSize,
1382 uint64_t TypeSize,
1383 bool FieldPacked,
1384 const FieldDecl *D) {
1385 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1386, __PRETTY_FUNCTION__))
1386 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1386, __PRETTY_FUNCTION__))
;
1387
1388 // Itanium C++ ABI 2.4:
1389 // If sizeof(T)*8 < n, let T' be the largest integral POD type with
1390 // sizeof(T')*8 <= n.
1391
1392 QualType IntegralPODTypes[] = {
1393 Context.UnsignedCharTy, Context.UnsignedShortTy, Context.UnsignedIntTy,
1394 Context.UnsignedLongTy, Context.UnsignedLongLongTy
1395 };
1396
1397 QualType Type;
1398 for (const QualType &QT : IntegralPODTypes) {
1399 uint64_t Size = Context.getTypeSize(QT);
1400
1401 if (Size > FieldSize)
1402 break;
1403
1404 Type = QT;
1405 }
1406 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1406, __PRETTY_FUNCTION__))
;
1407
1408 CharUnits TypeAlign = Context.getTypeAlignInChars(Type);
1409
1410 // We're not going to use any of the unfilled bits in the last byte.
1411 UnfilledBitsInLastUnit = 0;
1412 LastBitfieldTypeSize = 0;
1413
1414 uint64_t FieldOffset;
1415 uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;
1416
1417 if (IsUnion) {
1418 uint64_t RoundedFieldSize = roundUpSizeToCharAlignment(FieldSize,
1419 Context);
1420 setDataSize(std::max(getDataSizeInBits(), RoundedFieldSize));
1421 FieldOffset = 0;
1422 } else {
1423 // The bitfield is allocated starting at the next offset aligned
1424 // appropriately for T', with length n bits.
1425 FieldOffset = llvm::alignTo(getDataSizeInBits(), Context.toBits(TypeAlign));
1426
1427 uint64_t NewSizeInBits = FieldOffset + FieldSize;
1428
1429 setDataSize(
1430 llvm::alignTo(NewSizeInBits, Context.getTargetInfo().getCharAlign()));
1431 UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;
1432 }
1433
1434 // Place this field at the current location.
1435 FieldOffsets.push_back(FieldOffset);
1436
1437 CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, FieldOffset,
1438 Context.toBits(TypeAlign), FieldPacked, D);
1439
1440 // Update the size.
1441 setSize(std::max(getSizeInBits(), getDataSizeInBits()));
1442
1443 // Remember max struct/class alignment.
1444 UpdateAlignment(TypeAlign);
1445}
1446
1447void ItaniumRecordLayoutBuilder::LayoutBitField(const FieldDecl *D) {
1448 bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
1449 uint64_t FieldSize = D->getBitWidthValue(Context);
1450 TypeInfo FieldInfo = Context.getTypeInfo(D->getType());
1451 uint64_t TypeSize = FieldInfo.Width;
1452 unsigned FieldAlign = FieldInfo.Align;
1453
1454 // UnfilledBitsInLastUnit is the difference between the end of the
1455 // last allocated bitfield (i.e. the first bit offset available for
1456 // bitfields) and the end of the current data size in bits (i.e. the
1457 // first bit offset available for non-bitfields). The current data
1458 // size in bits is always a multiple of the char size; additionally,
1459 // for ms_struct records it's also a multiple of the
1460 // LastBitfieldTypeSize (if set).
1461
1462 // The struct-layout algorithm is dictated by the platform ABI,
1463 // which in principle could use almost any rules it likes. In
1464 // practice, UNIXy targets tend to inherit the algorithm described
1465 // in the System V generic ABI. The basic bitfield layout rule in
1466 // System V is to place bitfields at the next available bit offset
1467 // where the entire bitfield would fit in an aligned storage unit of
1468 // the declared type; it's okay if an earlier or later non-bitfield
1469 // is allocated in the same storage unit. However, some targets
1470 // (those that !useBitFieldTypeAlignment(), e.g. ARM APCS) don't
1471 // require this storage unit to be aligned, and therefore always put
1472 // the bitfield at the next available bit offset.
1473
1474 // ms_struct basically requests a complete replacement of the
1475 // platform ABI's struct-layout algorithm, with the high-level goal
1476 // of duplicating MSVC's layout. For non-bitfields, this follows
1477 // the standard algorithm. The basic bitfield layout rule is to
1478 // allocate an entire unit of the bitfield's declared type
1479 // (e.g. 'unsigned long'), then parcel it up among successive
1480 // bitfields whose declared types have the same size, making a new
1481 // unit as soon as the last can no longer store the whole value.
1482 // Since it completely replaces the platform ABI's algorithm,
1483 // settings like !useBitFieldTypeAlignment() do not apply.
1484
1485 // A zero-width bitfield forces the use of a new storage unit for
1486 // later bitfields. In general, this occurs by rounding up the
1487 // current size of the struct as if the algorithm were about to
1488 // place a non-bitfield of the field's formal type. Usually this
1489 // does not change the alignment of the struct itself, but it does
1490 // on some targets (those that useZeroLengthBitfieldAlignment(),
1491 // e.g. ARM). In ms_struct layout, zero-width bitfields are
1492 // ignored unless they follow a non-zero-width bitfield.
1493
1494 // A field alignment restriction (e.g. from #pragma pack) or
1495 // specification (e.g. from __attribute__((aligned))) changes the
1496 // formal alignment of the field. For System V, this alters the
1497 // required alignment of the notional storage unit that must contain
1498 // the bitfield. For ms_struct, this only affects the placement of
1499 // new storage units. In both cases, the effect of #pragma pack is
1500 // ignored on zero-width bitfields.
1501
1502 // On System V, a packed field (e.g. from #pragma pack or
1503 // __attribute__((packed))) always uses the next available bit
1504 // offset.
1505
1506 // In an ms_struct struct, the alignment of a fundamental type is
1507 // always equal to its size. This is necessary in order to mimic
1508 // the i386 alignment rules on targets which might not fully align
1509 // all types (e.g. Darwin PPC32, where alignof(long long) == 4).
1510
1511 // First, some simple bookkeeping to perform for ms_struct structs.
1512 if (IsMsStruct) {
1513 // The field alignment for integer types is always the size.
1514 FieldAlign = TypeSize;
1515
1516 // If the previous field was not a bitfield, or was a bitfield
1517 // with a different storage unit size, or if this field doesn't fit into
1518 // the current storage unit, we're done with that storage unit.
1519 if (LastBitfieldTypeSize != TypeSize ||
1520 UnfilledBitsInLastUnit < FieldSize) {
1521 // Also, ignore zero-length bitfields after non-bitfields.
1522 if (!LastBitfieldTypeSize && !FieldSize)
1523 FieldAlign = 1;
1524
1525 UnfilledBitsInLastUnit = 0;
1526 LastBitfieldTypeSize = 0;
1527 }
1528 }
1529
1530 // If the field is wider than its declared type, it follows
1531 // different rules in all cases.
1532 if (FieldSize > TypeSize) {
1533 LayoutWideBitField(FieldSize, TypeSize, FieldPacked, D);
1534 return;
1535 }
1536
1537 // Compute the next available bit offset.
1538 uint64_t FieldOffset =
1539 IsUnion ? 0 : (getDataSizeInBits() - UnfilledBitsInLastUnit);
1540
1541 // Handle targets that don't honor bitfield type alignment.
1542 if (!IsMsStruct && !Context.getTargetInfo().useBitFieldTypeAlignment()) {
1543 // Some such targets do honor it on zero-width bitfields.
1544 if (FieldSize == 0 &&
1545 Context.getTargetInfo().useZeroLengthBitfieldAlignment()) {
1546 // The alignment to round up to is the max of the field's natural
1547 // alignment and a target-specific fixed value (sometimes zero).
1548 unsigned ZeroLengthBitfieldBoundary =
1549 Context.getTargetInfo().getZeroLengthBitfieldBoundary();
1550 FieldAlign = std::max(FieldAlign, ZeroLengthBitfieldBoundary);
1551
1552 // If that doesn't apply, just ignore the field alignment.
1553 } else {
1554 FieldAlign = 1;
1555 }
1556 }
1557
1558 // Remember the alignment we would have used if the field were not packed.
1559 unsigned UnpackedFieldAlign = FieldAlign;
1560
1561 // Ignore the field alignment if the field is packed unless it has zero-size.
1562 if (!IsMsStruct && FieldPacked && FieldSize != 0)
1563 FieldAlign = 1;
1564
1565 // But, if there's an 'aligned' attribute on the field, honor that.
1566 unsigned ExplicitFieldAlign = D->getMaxAlignment();
1567 if (ExplicitFieldAlign) {
1568 FieldAlign = std::max(FieldAlign, ExplicitFieldAlign);
1569 UnpackedFieldAlign = std::max(UnpackedFieldAlign, ExplicitFieldAlign);
1570 }
1571
1572 // But, if there's a #pragma pack in play, that takes precedent over
1573 // even the 'aligned' attribute, for non-zero-width bitfields.
1574 unsigned MaxFieldAlignmentInBits = Context.toBits(MaxFieldAlignment);
1575 if (!MaxFieldAlignment.isZero() && FieldSize) {
1576 UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignmentInBits);
1577 if (FieldPacked)
1578 FieldAlign = UnpackedFieldAlign;
1579 else
1580 FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
1581 }
1582
1583 // But, ms_struct just ignores all of that in unions, even explicit
1584 // alignment attributes.
1585 if (IsMsStruct && IsUnion) {
1586 FieldAlign = UnpackedFieldAlign = 1;
1587 }
1588
1589 // For purposes of diagnostics, we're going to simultaneously
1590 // compute the field offsets that we would have used if we weren't
1591 // adding any alignment padding or if the field weren't packed.
1592 uint64_t UnpaddedFieldOffset = FieldOffset;
1593 uint64_t UnpackedFieldOffset = FieldOffset;
1594
1595 // Check if we need to add padding to fit the bitfield within an
1596 // allocation unit with the right size and alignment. The rules are
1597 // somewhat different here for ms_struct structs.
1598 if (IsMsStruct) {
1599 // If it's not a zero-width bitfield, and we can fit the bitfield
1600 // into the active storage unit (and we haven't already decided to
1601 // start a new storage unit), just do so, regardless of any other
1602 // other consideration. Otherwise, round up to the right alignment.
1603 if (FieldSize == 0 || FieldSize > UnfilledBitsInLastUnit) {
1604 FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
1605 UnpackedFieldOffset =
1606 llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
1607 UnfilledBitsInLastUnit = 0;
1608 }
1609
1610 } else {
1611 // #pragma pack, with any value, suppresses the insertion of padding.
1612 bool AllowPadding = MaxFieldAlignment.isZero();
1613
1614 // Compute the real offset.
1615 if (FieldSize == 0 ||
1616 (AllowPadding &&
1617 (FieldOffset & (FieldAlign-1)) + FieldSize > TypeSize)) {
1618 FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
1619 } else if (ExplicitFieldAlign &&
1620 (MaxFieldAlignmentInBits == 0 ||
1621 ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
1622 Context.getTargetInfo().useExplicitBitFieldAlignment()) {
1623 // TODO: figure it out what needs to be done on targets that don't honor
1624 // bit-field type alignment like ARM APCS ABI.
1625 FieldOffset = llvm::alignTo(FieldOffset, ExplicitFieldAlign);
1626 }
1627
1628 // Repeat the computation for diagnostic purposes.
1629 if (FieldSize == 0 ||
1630 (AllowPadding &&
1631 (UnpackedFieldOffset & (UnpackedFieldAlign-1)) + FieldSize > TypeSize))
1632 UnpackedFieldOffset =
1633 llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
1634 else if (ExplicitFieldAlign &&
1635 (MaxFieldAlignmentInBits == 0 ||
1636 ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
1637 Context.getTargetInfo().useExplicitBitFieldAlignment())
1638 UnpackedFieldOffset =
1639 llvm::alignTo(UnpackedFieldOffset, ExplicitFieldAlign);
1640 }
1641
1642 // If we're using external layout, give the external layout a chance
1643 // to override this information.
1644 if (UseExternalLayout)
1645 FieldOffset = updateExternalFieldOffset(D, FieldOffset);
1646
1647 // Okay, place the bitfield at the calculated offset.
1648 FieldOffsets.push_back(FieldOffset);
1649
1650 // Bookkeeping:
1651
1652 // Anonymous members don't affect the overall record alignment,
1653 // except on targets where they do.
1654 if (!IsMsStruct &&
1655 !Context.getTargetInfo().useZeroLengthBitfieldAlignment() &&
1656 !D->getIdentifier())
1657 FieldAlign = UnpackedFieldAlign = 1;
1658
1659 // Diagnose differences in layout due to padding or packing.
1660 if (!UseExternalLayout)
1661 CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, UnpackedFieldOffset,
1662 UnpackedFieldAlign, FieldPacked, D);
1663
1664 // Update DataSize to include the last byte containing (part of) the bitfield.
1665
1666 // For unions, this is just a max operation, as usual.
1667 if (IsUnion) {
1668 // For ms_struct, allocate the entire storage unit --- unless this
1669 // is a zero-width bitfield, in which case just use a size of 1.
1670 uint64_t RoundedFieldSize;
1671 if (IsMsStruct) {
1672 RoundedFieldSize =
1673 (FieldSize ? TypeSize : Context.getTargetInfo().getCharWidth());
1674
1675 // Otherwise, allocate just the number of bytes required to store
1676 // the bitfield.
1677 } else {
1678 RoundedFieldSize = roundUpSizeToCharAlignment(FieldSize, Context);
1679 }
1680 setDataSize(std::max(getDataSizeInBits(), RoundedFieldSize));
1681
1682 // For non-zero-width bitfields in ms_struct structs, allocate a new
1683 // storage unit if necessary.
1684 } else if (IsMsStruct && FieldSize) {
1685 // We should have cleared UnfilledBitsInLastUnit in every case
1686 // where we changed storage units.
1687 if (!UnfilledBitsInLastUnit) {
1688 setDataSize(FieldOffset + TypeSize);
1689 UnfilledBitsInLastUnit = TypeSize;
1690 }
1691 UnfilledBitsInLastUnit -= FieldSize;
1692 LastBitfieldTypeSize = TypeSize;
1693
1694 // Otherwise, bump the data size up to include the bitfield,
1695 // including padding up to char alignment, and then remember how
1696 // bits we didn't use.
1697 } else {
1698 uint64_t NewSizeInBits = FieldOffset + FieldSize;
1699 uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
1700 setDataSize(llvm::alignTo(NewSizeInBits, CharAlignment));
1701 UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;
1702
1703 // The only time we can get here for an ms_struct is if this is a
1704 // zero-width bitfield, which doesn't count as anything for the
1705 // purposes of unfilled bits.
1706 LastBitfieldTypeSize = 0;
1707 }
1708
1709 // Update the size.
1710 setSize(std::max(getSizeInBits(), getDataSizeInBits()));
1711
1712 // Remember max struct/class alignment.
1713 UnadjustedAlignment =
1714 std::max(UnadjustedAlignment, Context.toCharUnitsFromBits(FieldAlign));
1715 UpdateAlignment(Context.toCharUnitsFromBits(FieldAlign),
1716 Context.toCharUnitsFromBits(UnpackedFieldAlign));
1717}
1718
1719void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D,
1720 bool InsertExtraPadding) {
1721 if (D->isBitField()) {
1722 LayoutBitField(D);
1723 return;
1724 }
1725
1726 uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;
1727
1728 // Reset the unfilled bits.
1729 UnfilledBitsInLastUnit = 0;
1730 LastBitfieldTypeSize = 0;
1731
1732 bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
1733 CharUnits FieldOffset =
1734 IsUnion ? CharUnits::Zero() : getDataSize();
1735 CharUnits FieldSize;
1736 CharUnits FieldAlign;
1737
1738 if (D->getType()->isIncompleteArrayType()) {
1739 // This is a flexible array member; we can't directly
1740 // query getTypeInfo about these, so we figure it out here.
1741 // Flexible array members don't have any size, but they
1742 // have to be aligned appropriately for their element type.
1743 FieldSize = CharUnits::Zero();
1744 const ArrayType* ATy = Context.getAsArrayType(D->getType());
1745 FieldAlign = Context.getTypeAlignInChars(ATy->getElementType());
1746 } else if (const ReferenceType *RT = D->getType()->getAs<ReferenceType>()) {
1747 unsigned AS = Context.getTargetAddressSpace(RT->getPointeeType());
1748 FieldSize =
1749 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(AS));
1750 FieldAlign =
1751 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(AS));
1752 } else {
1753 std::pair<CharUnits, CharUnits> FieldInfo =
1754 Context.getTypeInfoInChars(D->getType());
1755 FieldSize = FieldInfo.first;
1756 FieldAlign = FieldInfo.second;
1757
1758 if (IsMsStruct) {
1759 // If MS bitfield layout is required, figure out what type is being
1760 // laid out and align the field to the width of that type.
1761
1762 // Resolve all typedefs down to their base type and round up the field
1763 // alignment if necessary.
1764 QualType T = Context.getBaseElementType(D->getType());
1765 if (const BuiltinType *BTy = T->getAs<BuiltinType>()) {
1766 CharUnits TypeSize = Context.getTypeSizeInChars(BTy);
1767
1768 if (!llvm::isPowerOf2_64(TypeSize.getQuantity())) {
1769 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1771, __PRETTY_FUNCTION__))
1770 !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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1771, __PRETTY_FUNCTION__))
1771 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1771, __PRETTY_FUNCTION__))
;
1772 // Base types with sizes that aren't a power of two don't work
1773 // with the layout rules for MS structs. This isn't an issue in
1774 // MSVC itself since there are no such base data types there.
1775 // On e.g. x86_32 mingw and linux, long double is 12 bytes though.
1776 // Any structs involving that data type obviously can't be ABI
1777 // compatible with MSVC regardless of how it is laid out.
1778
1779 // Since ms_struct can be mass enabled (via a pragma or via the
1780 // -mms-bitfields command line parameter), this can trigger for
1781 // structs that don't actually need MSVC compatibility, so we
1782 // need to be able to sidestep the ms_struct layout for these types.
1783
1784 // Since the combination of -mms-bitfields together with structs
1785 // like max_align_t (which contains a long double) for mingw is
1786 // quite comon (and GCC handles it silently), just handle it
1787 // silently there. For other targets that have ms_struct enabled
1788 // (most probably via a pragma or attribute), trigger a diagnostic
1789 // that defaults to an error.
1790 if (!Context.getTargetInfo().getTriple().isWindowsGNUEnvironment())
1791 Diag(D->getLocation(), diag::warn_npot_ms_struct);
1792 }
1793 if (TypeSize > FieldAlign &&
1794 llvm::isPowerOf2_64(TypeSize.getQuantity()))
1795 FieldAlign = TypeSize;
1796 }
1797 }
1798 }
1799
1800 // The align if the field is not packed. This is to check if the attribute
1801 // was unnecessary (-Wpacked).
1802 CharUnits UnpackedFieldAlign = FieldAlign;
1803 CharUnits UnpackedFieldOffset = FieldOffset;
1804
1805 if (FieldPacked)
1806 FieldAlign = CharUnits::One();
1807 CharUnits MaxAlignmentInChars =
1808 Context.toCharUnitsFromBits(D->getMaxAlignment());
1809 FieldAlign = std::max(FieldAlign, MaxAlignmentInChars);
1810 UnpackedFieldAlign = std::max(UnpackedFieldAlign, MaxAlignmentInChars);
1811
1812 // The maximum field alignment overrides the aligned attribute.
1813 if (!MaxFieldAlignment.isZero()) {
1814 FieldAlign = std::min(FieldAlign, MaxFieldAlignment);
1815 UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignment);
1816 }
1817
1818 // Round up the current record size to the field's alignment boundary.
1819 FieldOffset = FieldOffset.alignTo(FieldAlign);
1820 UnpackedFieldOffset = UnpackedFieldOffset.alignTo(UnpackedFieldAlign);
1821
1822 if (UseExternalLayout) {
1823 FieldOffset = Context.toCharUnitsFromBits(
1824 updateExternalFieldOffset(D, Context.toBits(FieldOffset)));
1825
1826 if (!IsUnion && EmptySubobjects) {
1827 // Record the fact that we're placing a field at this offset.
1828 bool Allowed = EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset);
1829 (void)Allowed;
1830 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1830, __PRETTY_FUNCTION__))
;
1831 }
1832 } else {
1833 if (!IsUnion && EmptySubobjects) {
1834 // Check if we can place the field at this offset.
1835 while (!EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset)) {
1836 // We couldn't place the field at the offset. Try again at a new offset.
1837 FieldOffset += FieldAlign;
1838 }
1839 }
1840 }
1841
1842 // Place this field at the current location.
1843 FieldOffsets.push_back(Context.toBits(FieldOffset));
1844
1845 if (!UseExternalLayout)
1846 CheckFieldPadding(Context.toBits(FieldOffset), UnpaddedFieldOffset,
1847 Context.toBits(UnpackedFieldOffset),
1848 Context.toBits(UnpackedFieldAlign), FieldPacked, D);
1849
1850 if (InsertExtraPadding) {
1851 CharUnits ASanAlignment = CharUnits::fromQuantity(8);
1852 CharUnits ExtraSizeForAsan = ASanAlignment;
1853 if (FieldSize % ASanAlignment)
1854 ExtraSizeForAsan +=
1855 ASanAlignment - CharUnits::fromQuantity(FieldSize % ASanAlignment);
1856 FieldSize += ExtraSizeForAsan;
1857 }
1858
1859 // Reserve space for this field.
1860 uint64_t FieldSizeInBits = Context.toBits(FieldSize);
1861 if (IsUnion)
1862 setDataSize(std::max(getDataSizeInBits(), FieldSizeInBits));
1863 else
1864 setDataSize(FieldOffset + FieldSize);
1865
1866 // Update the size.
1867 setSize(std::max(getSizeInBits(), getDataSizeInBits()));
1868
1869 // Remember max struct/class alignment.
1870 UnadjustedAlignment = std::max(UnadjustedAlignment, FieldAlign);
1871 UpdateAlignment(FieldAlign, UnpackedFieldAlign);
1872}
1873
1874void ItaniumRecordLayoutBuilder::FinishLayout(const NamedDecl *D) {
1875 // In C++, records cannot be of size 0.
1876 if (Context.getLangOpts().CPlusPlus && getSizeInBits() == 0) {
1877 if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
1878 // Compatibility with gcc requires a class (pod or non-pod)
1879 // which is not empty but of size 0; such as having fields of
1880 // array of zero-length, remains of Size 0
1881 if (RD->isEmpty())
1882 setSize(CharUnits::One());
1883 }
1884 else
1885 setSize(CharUnits::One());
1886 }
1887
1888 // Finally, round the size of the record up to the alignment of the
1889 // record itself.
1890 uint64_t UnpaddedSize = getSizeInBits() - UnfilledBitsInLastUnit;
1891 uint64_t UnpackedSizeInBits =
1892 llvm::alignTo(getSizeInBits(), Context.toBits(UnpackedAlignment));
1893 uint64_t RoundedSize =
1894 llvm::alignTo(getSizeInBits(), Context.toBits(Alignment));
1895
1896 if (UseExternalLayout) {
1897 // If we're inferring alignment, and the external size is smaller than
1898 // our size after we've rounded up to alignment, conservatively set the
1899 // alignment to 1.
1900 if (InferAlignment && External.Size < RoundedSize) {
1901 Alignment = CharUnits::One();
1902 InferAlignment = false;
1903 }
1904 setSize(External.Size);
1905 return;
1906 }
1907
1908 // Set the size to the final size.
1909 setSize(RoundedSize);
1910
1911 unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
1912 if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
1913 // Warn if padding was introduced to the struct/class/union.
1914 if (getSizeInBits() > UnpaddedSize) {
1915 unsigned PadSize = getSizeInBits() - UnpaddedSize;
1916 bool InBits = true;
1917 if (PadSize % CharBitNum == 0) {
1918 PadSize = PadSize / CharBitNum;
1919 InBits = false;
1920 }
1921 Diag(RD->getLocation(), diag::warn_padded_struct_size)
1922 << Context.getTypeDeclType(RD)
1923 << PadSize
1924 << (InBits ? 1 : 0); // (byte|bit)
1925 }
1926
1927 // Warn if we packed it unnecessarily, when the unpacked alignment is not
1928 // greater than the one after packing, the size in bits doesn't change and
1929 // the offset of each field is identical.
1930 if (Packed && UnpackedAlignment <= Alignment &&
1931 UnpackedSizeInBits == getSizeInBits() && !HasPackedField)
1932 Diag(D->getLocation(), diag::warn_unnecessary_packed)
1933 << Context.getTypeDeclType(RD);
1934 }
1935}
1936
1937void ItaniumRecordLayoutBuilder::UpdateAlignment(
1938 CharUnits NewAlignment, CharUnits UnpackedNewAlignment) {
1939 // The alignment is not modified when using 'mac68k' alignment or when
1940 // we have an externally-supplied layout that also provides overall alignment.
1941 if (IsMac68kAlign || (UseExternalLayout && !InferAlignment))
1942 return;
1943
1944 if (NewAlignment > Alignment) {
1945 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1946, __PRETTY_FUNCTION__))
1946 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1946, __PRETTY_FUNCTION__))
;
1947 Alignment = NewAlignment;
1948 }
1949
1950 if (UnpackedNewAlignment > UnpackedAlignment) {
1951 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1952, __PRETTY_FUNCTION__))
1952 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1952, __PRETTY_FUNCTION__))
;
1953 UnpackedAlignment = UnpackedNewAlignment;
1954 }
1955}
1956
1957uint64_t
1958ItaniumRecordLayoutBuilder::updateExternalFieldOffset(const FieldDecl *Field,
1959 uint64_t ComputedOffset) {
1960 uint64_t ExternalFieldOffset = External.getExternalFieldOffset(Field);
1961
1962 if (InferAlignment && ExternalFieldOffset < ComputedOffset) {
1963 // The externally-supplied field offset is before the field offset we
1964 // computed. Assume that the structure is packed.
1965 Alignment = CharUnits::One();
1966 InferAlignment = false;
1967 }
1968
1969 // Use the externally-supplied field offset.
1970 return ExternalFieldOffset;
1971}
1972
1973/// Get diagnostic %select index for tag kind for
1974/// field padding diagnostic message.
1975/// WARNING: Indexes apply to particular diagnostics only!
1976///
1977/// \returns diagnostic %select index.
1978static unsigned getPaddingDiagFromTagKind(TagTypeKind Tag) {
1979 switch (Tag) {
1980 case TTK_Struct: return 0;
1981 case TTK_Interface: return 1;
1982 case TTK_Class: return 2;
1983 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1983)
;
1984 }
1985}
1986
1987void ItaniumRecordLayoutBuilder::CheckFieldPadding(
1988 uint64_t Offset, uint64_t UnpaddedOffset, uint64_t UnpackedOffset,
1989 unsigned UnpackedAlign, bool isPacked, const FieldDecl *D) {
1990 // We let objc ivars without warning, objc interfaces generally are not used
1991 // for padding tricks.
1992 if (isa<ObjCIvarDecl>(D))
1993 return;
1994
1995 // Don't warn about structs created without a SourceLocation. This can
1996 // be done by clients of the AST, such as codegen.
1997 if (D->getLocation().isInvalid())
1998 return;
1999
2000 unsigned CharBitNum = Context.getTargetInfo().getCharWidth();
2001
2002 // Warn if padding was introduced to the struct/class.
2003 if (!IsUnion && Offset > UnpaddedOffset) {
2004 unsigned PadSize = Offset - UnpaddedOffset;
2005 bool InBits = true;
2006 if (PadSize % CharBitNum == 0) {
2007 PadSize = PadSize / CharBitNum;
2008 InBits = false;
2009 }
2010 if (D->getIdentifier())
2011 Diag(D->getLocation(), diag::warn_padded_struct_field)
2012 << getPaddingDiagFromTagKind(D->getParent()->getTagKind())
2013 << Context.getTypeDeclType(D->getParent())
2014 << PadSize
2015 << (InBits ? 1 : 0) // (byte|bit)
2016 << D->getIdentifier();
2017 else
2018 Diag(D->getLocation(), diag::warn_padded_struct_anon_field)
2019 << getPaddingDiagFromTagKind(D->getParent()->getTagKind())
2020 << Context.getTypeDeclType(D->getParent())
2021 << PadSize
2022 << (InBits ? 1 : 0); // (byte|bit)
2023 }
2024 if (isPacked && Offset != UnpackedOffset) {
2025 HasPackedField = true;
2026 }
2027}
2028
2029static const CXXMethodDecl *computeKeyFunction(ASTContext &Context,
2030 const CXXRecordDecl *RD) {
2031 // If a class isn't polymorphic it doesn't have a key function.
2032 if (!RD->isPolymorphic())
2033 return nullptr;
2034
2035 // A class that is not externally visible doesn't have a key function. (Or
2036 // at least, there's no point to assigning a key function to such a class;
2037 // this doesn't affect the ABI.)
2038 if (!RD->isExternallyVisible())
2039 return nullptr;
2040
2041 // Template instantiations don't have key functions per Itanium C++ ABI 5.2.6.
2042 // Same behavior as GCC.
2043 TemplateSpecializationKind TSK = RD->getTemplateSpecializationKind();
2044 if (TSK == TSK_ImplicitInstantiation ||
2045 TSK == TSK_ExplicitInstantiationDeclaration ||
2046 TSK == TSK_ExplicitInstantiationDefinition)
2047 return nullptr;
2048
2049 bool allowInlineFunctions =
2050 Context.getTargetInfo().getCXXABI().canKeyFunctionBeInline();
2051
2052 for (const CXXMethodDecl *MD : RD->methods()) {
2053 if (!MD->isVirtual())
2054 continue;
2055
2056 if (MD->isPure())
2057 continue;
2058
2059 // Ignore implicit member functions, they are always marked as inline, but
2060 // they don't have a body until they're defined.
2061 if (MD->isImplicit())
2062 continue;
2063
2064 if (MD->isInlineSpecified())
2065 continue;
2066
2067 if (MD->hasInlineBody())
2068 continue;
2069
2070 // Ignore inline deleted or defaulted functions.
2071 if (!MD->isUserProvided())
2072 continue;
2073
2074 // In certain ABIs, ignore functions with out-of-line inline definitions.
2075 if (!allowInlineFunctions) {
2076 const FunctionDecl *Def;
2077 if (MD->hasBody(Def) && Def->isInlineSpecified())
2078 continue;
2079 }
2080
2081 if (Context.getLangOpts().CUDA) {
2082 // While compiler may see key method in this TU, during CUDA
2083 // compilation we should ignore methods that are not accessible
2084 // on this side of compilation.
2085 if (Context.getLangOpts().CUDAIsDevice) {
2086 // In device mode ignore methods without __device__ attribute.
2087 if (!MD->hasAttr<CUDADeviceAttr>())
2088 continue;
2089 } else {
2090 // In host mode ignore __device__-only methods.
2091 if (!MD->hasAttr<CUDAHostAttr>() && MD->hasAttr<CUDADeviceAttr>())
2092 continue;
2093 }
2094 }
2095
2096 // If the key function is dllimport but the class isn't, then the class has
2097 // no key function. The DLL that exports the key function won't export the
2098 // vtable in this case.
2099 if (MD->hasAttr<DLLImportAttr>() && !RD->hasAttr<DLLImportAttr>())
2100 return nullptr;
2101
2102 // We found it.
2103 return MD;
2104 }
2105
2106 return nullptr;
2107}
2108
2109DiagnosticBuilder ItaniumRecordLayoutBuilder::Diag(SourceLocation Loc,
2110 unsigned DiagID) {
2111 return Context.getDiagnostics().Report(Loc, DiagID);
2112}
2113
2114/// Does the target C++ ABI require us to skip over the tail-padding
2115/// of the given class (considering it as a base class) when allocating
2116/// objects?
2117static bool mustSkipTailPadding(TargetCXXABI ABI, const CXXRecordDecl *RD) {
2118 switch (ABI.getTailPaddingUseRules()) {
2119 case TargetCXXABI::AlwaysUseTailPadding:
2120 return false;
2121
2122 case TargetCXXABI::UseTailPaddingUnlessPOD03:
2123 // FIXME: To the extent that this is meant to cover the Itanium ABI
2124 // rules, we should implement the restrictions about over-sized
2125 // bitfields:
2126 //
2127 // http://itanium-cxx-abi.github.io/cxx-abi/abi.html#POD :
2128 // In general, a type is considered a POD for the purposes of
2129 // layout if it is a POD type (in the sense of ISO C++
2130 // [basic.types]). However, a POD-struct or POD-union (in the
2131 // sense of ISO C++ [class]) with a bitfield member whose
2132 // declared width is wider than the declared type of the
2133 // bitfield is not a POD for the purpose of layout. Similarly,
2134 // an array type is not a POD for the purpose of layout if the
2135 // element type of the array is not a POD for the purpose of
2136 // layout.
2137 //
2138 // Where references to the ISO C++ are made in this paragraph,
2139 // the Technical Corrigendum 1 version of the standard is
2140 // intended.
2141 return RD->isPOD();
2142
2143 case TargetCXXABI::UseTailPaddingUnlessPOD11:
2144 // This is equivalent to RD->getTypeForDecl().isCXX11PODType(),
2145 // but with a lot of abstraction penalty stripped off. This does
2146 // assume that these properties are set correctly even in C++98
2147 // mode; fortunately, that is true because we want to assign
2148 // consistently semantics to the type-traits intrinsics (or at
2149 // least as many of them as possible).
2150 return RD->isTrivial() && RD->isCXX11StandardLayout();
2151 }
2152
2153 llvm_unreachable("bad tail-padding use kind")::llvm::llvm_unreachable_internal("bad tail-padding use kind"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2153)
;
2154}
2155
2156static bool isMsLayout(const ASTContext &Context) {
2157 return Context.getTargetInfo().getCXXABI().isMicrosoft();
2158}
2159
2160// This section contains an implementation of struct layout that is, up to the
2161// included tests, compatible with cl.exe (2013). The layout produced is
2162// significantly different than those produced by the Itanium ABI. Here we note
2163// the most important differences.
2164//
2165// * The alignment of bitfields in unions is ignored when computing the
2166// alignment of the union.
2167// * The existence of zero-width bitfield that occurs after anything other than
2168// a non-zero length bitfield is ignored.
2169// * There is no explicit primary base for the purposes of layout. All bases
2170// with vfptrs are laid out first, followed by all bases without vfptrs.
2171// * The Itanium equivalent vtable pointers are split into a vfptr (virtual
2172// function pointer) and a vbptr (virtual base pointer). They can each be
2173// shared with a, non-virtual bases. These bases need not be the same. vfptrs
2174// always occur at offset 0. vbptrs can occur at an arbitrary offset and are
2175// placed after the lexicographically last non-virtual base. This placement
2176// is always before fields but can be in the middle of the non-virtual bases
2177// due to the two-pass layout scheme for non-virtual-bases.
2178// * Virtual bases sometimes require a 'vtordisp' field that is laid out before
2179// the virtual base and is used in conjunction with virtual overrides during
2180// construction and destruction. This is always a 4 byte value and is used as
2181// an alternative to constructor vtables.
2182// * vtordisps are allocated in a block of memory with size and alignment equal
2183// to the alignment of the completed structure (before applying __declspec(
2184// align())). The vtordisp always occur at the end of the allocation block,
2185// immediately prior to the virtual base.
2186// * vfptrs are injected after all bases and fields have been laid out. In
2187// order to guarantee proper alignment of all fields, the vfptr injection
2188// pushes all bases and fields back by the alignment imposed by those bases
2189// and fields. This can potentially add a significant amount of padding.
2190// vfptrs are always injected at offset 0.
2191// * vbptrs are injected after all bases and fields have been laid out. In
2192// order to guarantee proper alignment of all fields, the vfptr injection
2193// pushes all bases and fields back by the alignment imposed by those bases
2194// and fields. This can potentially add a significant amount of padding.
2195// vbptrs are injected immediately after the last non-virtual base as
2196// lexicographically ordered in the code. If this site isn't pointer aligned
2197// the vbptr is placed at the next properly aligned location. Enough padding
2198// is added to guarantee a fit.
2199// * The last zero sized non-virtual base can be placed at the end of the
2200// struct (potentially aliasing another object), or may alias with the first
2201// field, even if they are of the same type.
2202// * The last zero size virtual base may be placed at the end of the struct
2203// potentially aliasing another object.
2204// * The ABI attempts to avoid aliasing of zero sized bases by adding padding
2205// between bases or vbases with specific properties. The criteria for
2206// additional padding between two bases is that the first base is zero sized
2207// or ends with a zero sized subobject and the second base is zero sized or
2208// trails with a zero sized base or field (sharing of vfptrs can reorder the
2209// layout of the so the leading base is not always the first one declared).
2210// This rule does take into account fields that are not records, so padding
2211// will occur even if the last field is, e.g. an int. The padding added for
2212// bases is 1 byte. The padding added between vbases depends on the alignment
2213// of the object but is at least 4 bytes (in both 32 and 64 bit modes).
2214// * There is no concept of non-virtual alignment, non-virtual alignment and
2215// alignment are always identical.
2216// * There is a distinction between alignment and required alignment.
2217// __declspec(align) changes the required alignment of a struct. This
2218// alignment is _always_ obeyed, even in the presence of #pragma pack. A
2219// record inherits required alignment from all of its fields and bases.
2220// * __declspec(align) on bitfields has the effect of changing the bitfield's
2221// alignment instead of its required alignment. This is the only known way
2222// to make the alignment of a struct bigger than 8. Interestingly enough
2223// this alignment is also immune to the effects of #pragma pack and can be
2224// used to create structures with large alignment under #pragma pack.
2225// However, because it does not impact required alignment, such a structure,
2226// when used as a field or base, will not be aligned if #pragma pack is
2227// still active at the time of use.
2228//
2229// Known incompatibilities:
2230// * all: #pragma pack between fields in a record
2231// * 2010 and back: If the last field in a record is a bitfield, every object
2232// laid out after the record will have extra padding inserted before it. The
2233// extra padding will have size equal to the size of the storage class of the
2234// bitfield. 0 sized bitfields don't exhibit this behavior and the extra
2235// padding can be avoided by adding a 0 sized bitfield after the non-zero-
2236// sized bitfield.
2237// * 2012 and back: In 64-bit mode, if the alignment of a record is 16 or
2238// greater due to __declspec(align()) then a second layout phase occurs after
2239// The locations of the vf and vb pointers are known. This layout phase
2240// suffers from the "last field is a bitfield" bug in 2010 and results in
2241// _every_ field getting padding put in front of it, potentially including the
2242// vfptr, leaving the vfprt at a non-zero location which results in a fault if
2243// anything tries to read the vftbl. The second layout phase also treats
2244// bitfields as separate entities and gives them each storage rather than
2245// packing them. Additionally, because this phase appears to perform a
2246// (an unstable) sort on the members before laying them out and because merged
2247// bitfields have the same address, the bitfields end up in whatever order
2248// the sort left them in, a behavior we could never hope to replicate.
2249
2250namespace {
2251struct MicrosoftRecordLayoutBuilder {
2252 struct ElementInfo {
2253 CharUnits Size;
2254 CharUnits Alignment;
2255 };
2256 typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
2257 MicrosoftRecordLayoutBuilder(const ASTContext &Context) : Context(Context) {}
2258private:
2259 MicrosoftRecordLayoutBuilder(const MicrosoftRecordLayoutBuilder &) = delete;
2260 void operator=(const MicrosoftRecordLayoutBuilder &) = delete;
2261public:
2262 void layout(const RecordDecl *RD);
2263 void cxxLayout(const CXXRecordDecl *RD);
2264 /// Initializes size and alignment and honors some flags.
2265 void initializeLayout(const RecordDecl *RD);
2266 /// Initialized C++ layout, compute alignment and virtual alignment and
2267 /// existence of vfptrs and vbptrs. Alignment is needed before the vfptr is
2268 /// laid out.
2269 void initializeCXXLayout(const CXXRecordDecl *RD);
2270 void layoutNonVirtualBases(const CXXRecordDecl *RD);
2271 void layoutNonVirtualBase(const CXXRecordDecl *RD,
2272 const CXXRecordDecl *BaseDecl,
2273 const ASTRecordLayout &BaseLayout,
2274 const ASTRecordLayout *&PreviousBaseLayout);
2275 void injectVFPtr(const CXXRecordDecl *RD);
2276 void injectVBPtr(const CXXRecordDecl *RD);
2277 /// Lays out the fields of the record. Also rounds size up to
2278 /// alignment.
2279 void layoutFields(const RecordDecl *RD);
2280 void layoutField(const FieldDecl *FD);
2281 void layoutBitField(const FieldDecl *FD);
2282 /// Lays out a single zero-width bit-field in the record and handles
2283 /// special cases associated with zero-width bit-fields.
2284 void layoutZeroWidthBitField(const FieldDecl *FD);
2285 void layoutVirtualBases(const CXXRecordDecl *RD);
2286 void finalizeLayout(const RecordDecl *RD);
2287 /// Gets the size and alignment of a base taking pragma pack and
2288 /// __declspec(align) into account.
2289 ElementInfo getAdjustedElementInfo(const ASTRecordLayout &Layout);
2290 /// Gets the size and alignment of a field taking pragma pack and
2291 /// __declspec(align) into account. It also updates RequiredAlignment as a
2292 /// side effect because it is most convenient to do so here.
2293 ElementInfo getAdjustedElementInfo(const FieldDecl *FD);
2294 /// Places a field at an offset in CharUnits.
2295 void placeFieldAtOffset(CharUnits FieldOffset) {
2296 FieldOffsets.push_back(Context.toBits(FieldOffset));
2297 }
2298 /// Places a bitfield at a bit offset.
2299 void placeFieldAtBitOffset(uint64_t FieldOffset) {
2300 FieldOffsets.push_back(FieldOffset);
2301 }
2302 /// Compute the set of virtual bases for which vtordisps are required.
2303 void computeVtorDispSet(
2304 llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtorDispSet,
2305 const CXXRecordDecl *RD) const;
2306 const ASTContext &Context;
2307 /// The size of the record being laid out.
2308 CharUnits Size;
2309 /// The non-virtual size of the record layout.
2310 CharUnits NonVirtualSize;
2311 /// The data size of the record layout.
2312 CharUnits DataSize;
2313 /// The current alignment of the record layout.
2314 CharUnits Alignment;
2315 /// The maximum allowed field alignment. This is set by #pragma pack.
2316 CharUnits MaxFieldAlignment;
2317 /// The alignment that this record must obey. This is imposed by
2318 /// __declspec(align()) on the record itself or one of its fields or bases.
2319 CharUnits RequiredAlignment;
2320 /// The size of the allocation of the currently active bitfield.
2321 /// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield
2322 /// is true.
2323 CharUnits CurrentBitfieldSize;
2324 /// Offset to the virtual base table pointer (if one exists).
2325 CharUnits VBPtrOffset;
2326 /// Minimum record size possible.
2327 CharUnits MinEmptyStructSize;
2328 /// The size and alignment info of a pointer.
2329 ElementInfo PointerInfo;
2330 /// The primary base class (if one exists).
2331 const CXXRecordDecl *PrimaryBase;
2332 /// The class we share our vb-pointer with.
2333 const CXXRecordDecl *SharedVBPtrBase;
2334 /// The collection of field offsets.
2335 SmallVector<uint64_t, 16> FieldOffsets;
2336 /// Base classes and their offsets in the record.
2337 BaseOffsetsMapTy Bases;
2338 /// virtual base classes and their offsets in the record.
2339 ASTRecordLayout::VBaseOffsetsMapTy VBases;
2340 /// The number of remaining bits in our last bitfield allocation.
2341 /// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield is
2342 /// true.
2343 unsigned RemainingBitsInField;
2344 bool IsUnion : 1;
2345 /// True if the last field laid out was a bitfield and was not 0
2346 /// width.
2347 bool LastFieldIsNonZeroWidthBitfield : 1;
2348 /// True if the class has its own vftable pointer.
2349 bool HasOwnVFPtr : 1;
2350 /// True if the class has a vbtable pointer.
2351 bool HasVBPtr : 1;
2352 /// True if the last sub-object within the type is zero sized or the
2353 /// object itself is zero sized. This *does not* count members that are not
2354 /// records. Only used for MS-ABI.
2355 bool EndsWithZeroSizedObject : 1;
2356 /// True if this class is zero sized or first base is zero sized or
2357 /// has this property. Only used for MS-ABI.
2358 bool LeadsWithZeroSizedBase : 1;
2359
2360 /// True if the external AST source provided a layout for this record.
2361 bool UseExternalLayout : 1;
2362
2363 /// The layout provided by the external AST source. Only active if
2364 /// UseExternalLayout is true.
2365 ExternalLayout External;
2366};
2367} // namespace
2368
2369MicrosoftRecordLayoutBuilder::ElementInfo
2370MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
2371 const ASTRecordLayout &Layout) {
2372 ElementInfo Info;
2373 Info.Alignment = Layout.getAlignment();
2374 // Respect pragma pack.
2375 if (!MaxFieldAlignment.isZero())
2376 Info.Alignment = std::min(Info.Alignment, MaxFieldAlignment);
2377 // Track zero-sized subobjects here where it's already available.
2378 EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
2379 // Respect required alignment, this is necessary because we may have adjusted
2380 // the alignment in the case of pragam pack. Note that the required alignment
2381 // doesn't actually apply to the struct alignment at this point.
2382 Alignment = std::max(Alignment, Info.Alignment);
2383 RequiredAlignment = std::max(RequiredAlignment, Layout.getRequiredAlignment());
2384 Info.Alignment = std::max(Info.Alignment, Layout.getRequiredAlignment());
2385 Info.Size = Layout.getNonVirtualSize();
2386 return Info;
2387}
2388
2389MicrosoftRecordLayoutBuilder::ElementInfo
2390MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
2391 const FieldDecl *FD) {
2392 // Get the alignment of the field type's natural alignment, ignore any
2393 // alignment attributes.
2394 ElementInfo Info;
2395 std::tie(Info.Size, Info.Alignment) =
2396 Context.getTypeInfoInChars(FD->getType()->getUnqualifiedDesugaredType());
2397 // Respect align attributes on the field.
2398 CharUnits FieldRequiredAlignment =
2399 Context.toCharUnitsFromBits(FD->getMaxAlignment());
2400 // Respect align attributes on the type.
2401 if (Context.isAlignmentRequired(FD->getType()))
2402 FieldRequiredAlignment = std::max(
2403 Context.getTypeAlignInChars(FD->getType()), FieldRequiredAlignment);
2404 // Respect attributes applied to subobjects of the field.
2405 if (FD->isBitField())
2406 // For some reason __declspec align impacts alignment rather than required
2407 // alignment when it is applied to bitfields.
2408 Info.Alignment = std::max(Info.Alignment, FieldRequiredAlignment);
2409 else {
2410 if (auto RT =
2411 FD->getType()->getBaseElementTypeUnsafe()->getAs<RecordType>()) {
2412 auto const &Layout = Context.getASTRecordLayout(RT->getDecl());
2413 EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
2414 FieldRequiredAlignment = std::max(FieldRequiredAlignment,
2415 Layout.getRequiredAlignment());
2416 }
2417 // Capture required alignment as a side-effect.
2418 RequiredAlignment = std::max(RequiredAlignment, FieldRequiredAlignment);
2419 }
2420 // Respect pragma pack, attribute pack and declspec align
2421 if (!MaxFieldAlignment.isZero())
2422 Info.Alignment = std::min(Info.Alignment, MaxFieldAlignment);
2423 if (FD->hasAttr<PackedAttr>())
2424 Info.Alignment = CharUnits::One();
2425 Info.Alignment = std::max(Info.Alignment, FieldRequiredAlignment);
2426 return Info;
2427}
2428
2429void MicrosoftRecordLayoutBuilder::layout(const RecordDecl *RD) {
2430 // For C record layout, zero-sized records always have size 4.
2431 MinEmptyStructSize = CharUnits::fromQuantity(4);
2432 initializeLayout(RD);
2433 layoutFields(RD);
2434 DataSize = Size = Size.alignTo(Alignment);
2435 RequiredAlignment = std::max(
2436 RequiredAlignment, Context.toCharUnitsFromBits(RD->getMaxAlignment()));
2437 finalizeLayout(RD);
2438}
2439
2440void MicrosoftRecordLayoutBuilder::cxxLayout(const CXXRecordDecl *RD) {
2441 // The C++ standard says that empty structs have size 1.
2442 MinEmptyStructSize = CharUnits::One();
2443 initializeLayout(RD);
2444 initializeCXXLayout(RD);
2445 layoutNonVirtualBases(RD);
2446 layoutFields(RD);
2447 injectVBPtr(RD);
2448 injectVFPtr(RD);
2449 if (HasOwnVFPtr || (HasVBPtr && !SharedVBPtrBase))
2450 Alignment = std::max(Alignment, PointerInfo.Alignment);
2451 auto RoundingAlignment = Alignment;
2452 if (!MaxFieldAlignment.isZero())
2453 RoundingAlignment = std::min(RoundingAlignment, MaxFieldAlignment);
2454 if (!UseExternalLayout)
2455 Size = Size.alignTo(RoundingAlignment);
2456 NonVirtualSize = Size;
2457 RequiredAlignment = std::max(
2458 RequiredAlignment, Context.toCharUnitsFromBits(RD->getMaxAlignment()));
2459 layoutVirtualBases(RD);
2460 finalizeLayout(RD);
2461}
2462
2463void MicrosoftRecordLayoutBuilder::initializeLayout(const RecordDecl *RD) {
2464 IsUnion = RD->isUnion();
2465 Size = CharUnits::Zero();
2466 Alignment = CharUnits::One();
2467 // In 64-bit mode we always perform an alignment step after laying out vbases.
2468 // In 32-bit mode we do not. The check to see if we need to perform alignment
2469 // checks the RequiredAlignment field and performs alignment if it isn't 0.
2470 RequiredAlignment = Context.getTargetInfo().getTriple().isArch64Bit()
2471 ? CharUnits::One()
2472 : CharUnits::Zero();
2473 // Compute the maximum field alignment.
2474 MaxFieldAlignment = CharUnits::Zero();
2475 // Honor the default struct packing maximum alignment flag.
2476 if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct)
2477 MaxFieldAlignment = CharUnits::fromQuantity(DefaultMaxFieldAlignment);
2478 // Honor the packing attribute. The MS-ABI ignores pragma pack if its larger
2479 // than the pointer size.
2480 if (const MaxFieldAlignmentAttr *MFAA = RD->getAttr<MaxFieldAlignmentAttr>()){
2481 unsigned PackedAlignment = MFAA->getAlignment();
2482 if (PackedAlignment <= Context.getTargetInfo().getPointerWidth(0))
2483 MaxFieldAlignment = Context.toCharUnitsFromBits(PackedAlignment);
2484 }
2485 // Packed attribute forces max field alignment to be 1.
2486 if (RD->hasAttr<PackedAttr>())
2487 MaxFieldAlignment = CharUnits::One();
2488
2489 // Try to respect the external layout if present.
2490 UseExternalLayout = false;
2491 if (ExternalASTSource *Source = Context.getExternalSource())
2492 UseExternalLayout = Source->layoutRecordType(
2493 RD, External.Size, External.Align, External.FieldOffsets,
2494 External.BaseOffsets, External.VirtualBaseOffsets);
2495}
2496
2497void
2498MicrosoftRecordLayoutBuilder::initializeCXXLayout(const CXXRecordDecl *RD) {
2499 EndsWithZeroSizedObject = false;
2500 LeadsWithZeroSizedBase = false;
2501 HasOwnVFPtr = false;
2502 HasVBPtr = false;
2503 PrimaryBase = nullptr;
2504 SharedVBPtrBase = nullptr;
2505 // Calculate pointer size and alignment. These are used for vfptr and vbprt
2506 // injection.
2507 PointerInfo.Size =
2508 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
2509 PointerInfo.Alignment =
2510 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(0));
2511 // Respect pragma pack.
2512 if (!MaxFieldAlignment.isZero())
2513 PointerInfo.Alignment = std::min(PointerInfo.Alignment, MaxFieldAlignment);
2514}
2515
2516void
2517MicrosoftRecordLayoutBuilder::layoutNonVirtualBases(const CXXRecordDecl *RD) {
2518 // The MS-ABI lays out all bases that contain leading vfptrs before it lays
2519 // out any bases that do not contain vfptrs. We implement this as two passes
2520 // over the bases. This approach guarantees that the primary base is laid out
2521 // first. We use these passes to calculate some additional aggregated
2522 // information about the bases, such as required alignment and the presence of
2523 // zero sized members.
2524 const ASTRecordLayout *PreviousBaseLayout = nullptr;
2525 // Iterate through the bases and lay out the non-virtual ones.
2526 for (const CXXBaseSpecifier &Base : RD->bases()) {
2527 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2528 const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2529 // Mark and skip virtual bases.
2530 if (Base.isVirtual()) {
2531 HasVBPtr = true;
2532 continue;
2533 }
2534 // Check for a base to share a VBPtr with.
2535 if (!SharedVBPtrBase && BaseLayout.hasVBPtr()) {
2536 SharedVBPtrBase = BaseDecl;
2537 HasVBPtr = true;
2538 }
2539 // Only lay out bases with extendable VFPtrs on the first pass.
2540 if (!BaseLayout.hasExtendableVFPtr())
2541 continue;
2542 // If we don't have a primary base, this one qualifies.
2543 if (!PrimaryBase) {
2544 PrimaryBase = BaseDecl;
2545 LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
2546 }
2547 // Lay out the base.
2548 layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
2549 }
2550 // Figure out if we need a fresh VFPtr for this class.
2551 if (!PrimaryBase && RD->isDynamicClass())
2552 for (CXXRecordDecl::method_iterator i = RD->method_begin(),
2553 e = RD->method_end();
2554 !HasOwnVFPtr && i != e; ++i)
2555 HasOwnVFPtr = i->isVirtual() && i->size_overridden_methods() == 0;
2556 // If we don't have a primary base then we have a leading object that could
2557 // itself lead with a zero-sized object, something we track.
2558 bool CheckLeadingLayout = !PrimaryBase;
2559 // Iterate through the bases and lay out the non-virtual ones.
2560 for (const CXXBaseSpecifier &Base : RD->bases()) {
2561 if (Base.isVirtual())
2562 continue;
2563 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2564 const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2565 // Only lay out bases without extendable VFPtrs on the second pass.
2566 if (BaseLayout.hasExtendableVFPtr()) {
2567 VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
2568 continue;
2569 }
2570 // If this is the first layout, check to see if it leads with a zero sized
2571 // object. If it does, so do we.
2572 if (CheckLeadingLayout) {
2573 CheckLeadingLayout = false;
2574 LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
2575 }
2576 // Lay out the base.
2577 layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
2578 VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
2579 }
2580 // Set our VBPtroffset if we know it at this point.
2581 if (!HasVBPtr)
2582 VBPtrOffset = CharUnits::fromQuantity(-1);
2583 else if (SharedVBPtrBase) {
2584 const ASTRecordLayout &Layout = Context.getASTRecordLayout(SharedVBPtrBase);
2585 VBPtrOffset = Bases[SharedVBPtrBase] + Layout.getVBPtrOffset();
2586 }
2587}
2588
2589static bool recordUsesEBO(const RecordDecl *RD) {
2590 if (!isa<CXXRecordDecl>(RD))
2591 return false;
2592 if (RD->hasAttr<EmptyBasesAttr>())
2593 return true;
2594 if (auto *LVA = RD->getAttr<LayoutVersionAttr>())
2595 // TODO: Double check with the next version of MSVC.
2596 if (LVA->getVersion() <= LangOptions::MSVC2015)
2597 return false;
2598 // TODO: Some later version of MSVC will change the default behavior of the
2599 // compiler to enable EBO by default. When this happens, we will need an
2600 // additional isCompatibleWithMSVC check.
2601 return false;
2602}
2603
2604void MicrosoftRecordLayoutBuilder::layoutNonVirtualBase(
2605 const CXXRecordDecl *RD,
2606 const CXXRecordDecl *BaseDecl,
2607 const ASTRecordLayout &BaseLayout,
2608 const ASTRecordLayout *&PreviousBaseLayout) {
2609 // Insert padding between two bases if the left first one is zero sized or
2610 // contains a zero sized subobject and the right is zero sized or one leads
2611 // with a zero sized base.
2612 bool MDCUsesEBO = recordUsesEBO(RD);
2613 if (PreviousBaseLayout && PreviousBaseLayout->endsWithZeroSizedObject() &&
2614 BaseLayout.leadsWithZeroSizedBase() && !MDCUsesEBO)
2615 Size++;
2616 ElementInfo Info = getAdjustedElementInfo(BaseLayout);
2617 CharUnits BaseOffset;
2618
2619 // Respect the external AST source base offset, if present.
2620 bool FoundBase = false;
2621 if (UseExternalLayout) {
2622 FoundBase = External.getExternalNVBaseOffset(BaseDecl, BaseOffset);
2623 if (FoundBase) {
2624 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2624, __PRETTY_FUNCTION__))
;
2625 Size = BaseOffset;
2626 }
2627 }
2628
2629 if (!FoundBase) {
2630 if (MDCUsesEBO && BaseDecl->isEmpty()) {
2631 assert(BaseLayout.getNonVirtualSize() == CharUnits::Zero())((BaseLayout.getNonVirtualSize() == CharUnits::Zero()) ? static_cast
<void> (0) : __assert_fail ("BaseLayout.getNonVirtualSize() == CharUnits::Zero()"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2631, __PRETTY_FUNCTION__))
;
2632 BaseOffset = CharUnits::Zero();
2633 } else {
2634 // Otherwise, lay the base out at the end of the MDC.
2635 BaseOffset = Size = Size.alignTo(Info.Alignment);
2636 }
2637 }
2638 Bases.insert(std::make_pair(BaseDecl, BaseOffset));
2639 Size += BaseLayout.getNonVirtualSize();
2640 PreviousBaseLayout = &BaseLayout;
2641}
2642
2643void MicrosoftRecordLayoutBuilder::layoutFields(const RecordDecl *RD) {
2644 LastFieldIsNonZeroWidthBitfield = false;
2645 for (const FieldDecl *Field : RD->fields())
2646 layoutField(Field);
2647}
2648
2649void MicrosoftRecordLayoutBuilder::layoutField(const FieldDecl *FD) {
2650 if (FD->isBitField()) {
2651 layoutBitField(FD);
2652 return;
2653 }
2654 LastFieldIsNonZeroWidthBitfield = false;
2655 ElementInfo Info = getAdjustedElementInfo(FD);
2656 Alignment = std::max(Alignment, Info.Alignment);
2657 CharUnits FieldOffset;
2658 if (UseExternalLayout)
2659 FieldOffset =
2660 Context.toCharUnitsFromBits(External.getExternalFieldOffset(FD));
2661 else if (IsUnion)
2662 FieldOffset = CharUnits::Zero();
2663 else
2664 FieldOffset = Size.alignTo(Info.Alignment);
2665 placeFieldAtOffset(FieldOffset);
2666 Size = std::max(Size, FieldOffset + Info.Size);
2667}
2668
2669void MicrosoftRecordLayoutBuilder::layoutBitField(const FieldDecl *FD) {
2670 unsigned Width = FD->getBitWidthValue(Context);
2671 if (Width == 0) {
2672 layoutZeroWidthBitField(FD);
2673 return;
2674 }
2675 ElementInfo Info = getAdjustedElementInfo(FD);
2676 // Clamp the bitfield to a containable size for the sake of being able
2677 // to lay them out. Sema will throw an error.
2678 if (Width > Context.toBits(Info.Size))
2679 Width = Context.toBits(Info.Size);
2680 // Check to see if this bitfield fits into an existing allocation. Note:
2681 // MSVC refuses to pack bitfields of formal types with different sizes
2682 // into the same allocation.
2683 if (!UseExternalLayout && !IsUnion && LastFieldIsNonZeroWidthBitfield &&
2684 CurrentBitfieldSize == Info.Size && Width <= RemainingBitsInField) {
2685 placeFieldAtBitOffset(Context.toBits(Size) - RemainingBitsInField);
2686 RemainingBitsInField -= Width;
2687 return;
2688 }
2689 LastFieldIsNonZeroWidthBitfield = true;
2690 CurrentBitfieldSize = Info.Size;
2691 if (UseExternalLayout) {
2692 auto FieldBitOffset = External.getExternalFieldOffset(FD);
2693 placeFieldAtBitOffset(FieldBitOffset);
2694 auto NewSize = Context.toCharUnitsFromBits(
2695 llvm::alignDown(FieldBitOffset, Context.toBits(Info.Alignment)) +
2696 Context.toBits(Info.Size));
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 // Determine where the first field should be laid out after the vbptr.
2746 CharUnits FieldStart = VBPtrOffset + PointerInfo.Size;
2747 // Shift everything after the vbptr down, unless we're using an external
2748 // layout.
2749 if (UseExternalLayout) {
2750 // It is possible that there were no fields or bases located after vbptr,
2751 // so the size was not adjusted before.
2752 if (Size < FieldStart)
2753 Size = FieldStart;
2754 return;
2755 }
2756 // Make sure that the amount we push the fields back by is a multiple of the
2757 // alignment.
2758 CharUnits Offset = (FieldStart - InjectionSite)
2759 .alignTo(std::max(RequiredAlignment, Alignment));
2760 Size += Offset;
2761 for (uint64_t &FieldOffset : FieldOffsets)
2762 FieldOffset += Context.toBits(Offset);
2763 for (BaseOffsetsMapTy::value_type &Base : Bases)
2764 if (Base.second >= InjectionSite)
2765 Base.second += Offset;
2766}
2767
2768void MicrosoftRecordLayoutBuilder::injectVFPtr(const CXXRecordDecl *RD) {
2769 if (!HasOwnVFPtr)
2770 return;
2771 // Make sure that the amount we push the struct back by is a multiple of the
2772 // alignment.
2773 CharUnits Offset =
2774 PointerInfo.Size.alignTo(std::max(RequiredAlignment, Alignment));
2775 // Push back the vbptr, but increase the size of the object and push back
2776 // regular fields by the offset only if not using external record layout.
2777 if (HasVBPtr)
2778 VBPtrOffset += Offset;
2779
2780 if (UseExternalLayout) {
2781 // The class may have no bases or fields, but still have a vfptr
2782 // (e.g. it's an interface class). The size was not correctly set before
2783 // in this case.
2784 if (FieldOffsets.empty() && Bases.empty())
2785 Size += Offset;
2786 return;
2787 }
2788
2789 Size += Offset;
2790
2791 // If we're using an external layout, the fields offsets have already
2792 // accounted for this adjustment.
2793 for (uint64_t &FieldOffset : FieldOffsets)
2794 FieldOffset += Context.toBits(Offset);
2795 for (BaseOffsetsMapTy::value_type &Base : Bases)
2796 Base.second += Offset;
2797}
2798
2799void MicrosoftRecordLayoutBuilder::layoutVirtualBases(const CXXRecordDecl *RD) {
2800 if (!HasVBPtr)
2801 return;
2802 // Vtordisps are always 4 bytes (even in 64-bit mode)
2803 CharUnits VtorDispSize = CharUnits::fromQuantity(4);
2804 CharUnits VtorDispAlignment = VtorDispSize;
2805 // vtordisps respect pragma pack.
2806 if (!MaxFieldAlignment.isZero())
2807 VtorDispAlignment = std::min(VtorDispAlignment, MaxFieldAlignment);
2808 // The alignment of the vtordisp is at least the required alignment of the
2809 // entire record. This requirement may be present to support vtordisp
2810 // injection.
2811 for (const CXXBaseSpecifier &VBase : RD->vbases()) {
2812 const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
2813 const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2814 RequiredAlignment =
2815 std::max(RequiredAlignment, BaseLayout.getRequiredAlignment());
2816 }
2817 VtorDispAlignment = std::max(VtorDispAlignment, RequiredAlignment);
2818 // Compute the vtordisp set.
2819 llvm::SmallPtrSet<const CXXRecordDecl *, 2> HasVtorDispSet;
2820 computeVtorDispSet(HasVtorDispSet, RD);
2821 // Iterate through the virtual bases and lay them out.
2822 const ASTRecordLayout *PreviousBaseLayout = nullptr;
2823 for (const CXXBaseSpecifier &VBase : RD->vbases()) {
2824 const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
2825 const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
2826 bool HasVtordisp = HasVtorDispSet.count(BaseDecl) > 0;
2827 // Insert padding between two bases if the left first one is zero sized or
2828 // contains a zero sized subobject and the right is zero sized or one leads
2829 // with a zero sized base. The padding between virtual bases is 4
2830 // bytes (in both 32 and 64 bits modes) and always involves rounding up to
2831 // the required alignment, we don't know why.
2832 if ((PreviousBaseLayout && PreviousBaseLayout->endsWithZeroSizedObject() &&
2833 BaseLayout.leadsWithZeroSizedBase() && !recordUsesEBO(RD)) ||
2834 HasVtordisp) {
2835 Size = Size.alignTo(VtorDispAlignment) + VtorDispSize;
2836 Alignment = std::max(VtorDispAlignment, Alignment);
2837 }
2838 // Insert the virtual base.
2839 ElementInfo Info = getAdjustedElementInfo(BaseLayout);
2840 CharUnits BaseOffset;
2841
2842 // Respect the external AST source base offset, if present.
2843 if (UseExternalLayout) {
2844 if (!External.getExternalVBaseOffset(BaseDecl, BaseOffset))
2845 BaseOffset = Size;
2846 } else
2847 BaseOffset = Size.alignTo(Info.Alignment);
2848
2849 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2849, __PRETTY_FUNCTION__))
;
2850
2851 VBases.insert(std::make_pair(BaseDecl,
2852 ASTRecordLayout::VBaseInfo(BaseOffset, HasVtordisp)));
2853 Size = BaseOffset + BaseLayout.getNonVirtualSize();
2854 PreviousBaseLayout = &BaseLayout;
2855 }
2856}
2857
2858void MicrosoftRecordLayoutBuilder::finalizeLayout(const RecordDecl *RD) {
2859 // Respect required alignment. Note that in 32-bit mode Required alignment
2860 // may be 0 and cause size not to be updated.
2861 DataSize = Size;
2862 if (!RequiredAlignment.isZero()) {
2863 Alignment = std::max(Alignment, RequiredAlignment);
2864 auto RoundingAlignment = Alignment;
2865 if (!MaxFieldAlignment.isZero())
2866 RoundingAlignment = std::min(RoundingAlignment, MaxFieldAlignment);
2867 RoundingAlignment = std::max(RoundingAlignment, RequiredAlignment);
2868 Size = Size.alignTo(RoundingAlignment);
2869 }
2870 if (Size.isZero()) {
2871 if (!recordUsesEBO(RD) || !cast<CXXRecordDecl>(RD)->isEmpty()) {
2872 EndsWithZeroSizedObject = true;
2873 LeadsWithZeroSizedBase = true;
2874 }
2875 // Zero-sized structures have size equal to their alignment if a
2876 // __declspec(align) came into play.
2877 if (RequiredAlignment >= MinEmptyStructSize)
2878 Size = Alignment;
2879 else
2880 Size = MinEmptyStructSize;
2881 }
2882
2883 if (UseExternalLayout) {
2884 Size = Context.toCharUnitsFromBits(External.Size);
2885 if (External.Align)
2886 Alignment = Context.toCharUnitsFromBits(External.Align);
2887 }
2888}
2889
2890// Recursively walks the non-virtual bases of a class and determines if any of
2891// them are in the bases with overridden methods set.
2892static bool
2893RequiresVtordisp(const llvm::SmallPtrSetImpl<const CXXRecordDecl *> &
2894 BasesWithOverriddenMethods,
2895 const CXXRecordDecl *RD) {
2896 if (BasesWithOverriddenMethods.count(RD))
2897 return true;
2898 // If any of a virtual bases non-virtual bases (recursively) requires a
2899 // vtordisp than so does this virtual base.
2900 for (const CXXBaseSpecifier &Base : RD->bases())
2901 if (!Base.isVirtual() &&
2902 RequiresVtordisp(BasesWithOverriddenMethods,
2903 Base.getType()->getAsCXXRecordDecl()))
2904 return true;
2905 return false;
2906}
2907
2908void MicrosoftRecordLayoutBuilder::computeVtorDispSet(
2909 llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtordispSet,
2910 const CXXRecordDecl *RD) const {
2911 // /vd2 or #pragma vtordisp(2): Always use vtordisps for virtual bases with
2912 // vftables.
2913 if (RD->getMSVtorDispMode() == MSVtorDispAttr::ForVFTable) {
2914 for (const CXXBaseSpecifier &Base : RD->vbases()) {
2915 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2916 const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
2917 if (Layout.hasExtendableVFPtr())
2918 HasVtordispSet.insert(BaseDecl);
2919 }
2920 return;
2921 }
2922
2923 // If any of our bases need a vtordisp for this type, so do we. Check our
2924 // direct bases for vtordisp requirements.
2925 for (const CXXBaseSpecifier &Base : RD->bases()) {
2926 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2927 const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
2928 for (const auto &bi : Layout.getVBaseOffsetsMap())
2929 if (bi.second.hasVtorDisp())
2930 HasVtordispSet.insert(bi.first);
2931 }
2932 // We don't introduce any additional vtordisps if either:
2933 // * A user declared constructor or destructor aren't declared.
2934 // * #pragma vtordisp(0) or the /vd0 flag are in use.
2935 if ((!RD->hasUserDeclaredConstructor() && !RD->hasUserDeclaredDestructor()) ||
2936 RD->getMSVtorDispMode() == MSVtorDispAttr::Never)
2937 return;
2938 // /vd1 or #pragma vtordisp(1): Try to guess based on whether we think it's
2939 // possible for a partially constructed object with virtual base overrides to
2940 // escape a non-trivial constructor.
2941 assert(RD->getMSVtorDispMode() == MSVtorDispAttr::ForVBaseOverride)((RD->getMSVtorDispMode() == MSVtorDispAttr::ForVBaseOverride
) ? static_cast<void> (0) : __assert_fail ("RD->getMSVtorDispMode() == MSVtorDispAttr::ForVBaseOverride"
, "/build/llvm-toolchain-snapshot-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2941, __PRETTY_FUNCTION__))
;
2942 // Compute a set of base classes which define methods we override. A virtual
2943 // base in this set will require a vtordisp. A virtual base that transitively
2944 // contains one of these bases as a non-virtual base will also require a
2945 // vtordisp.
2946 llvm::SmallPtrSet<const CXXMethodDecl *, 8> Work;
2947 llvm::SmallPtrSet<const CXXRecordDecl *, 2> BasesWithOverriddenMethods;
2948 // Seed the working set with our non-destructor, non-pure virtual methods.
2949 for (const CXXMethodDecl *MD : RD->methods())
2950 if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD) && !MD->isPure())
2951 Work.insert(MD);
2952 while (!Work.empty()) {
2953 const CXXMethodDecl *MD = *Work.begin();
2954 auto MethodRange = MD->overridden_methods();
2955 // If a virtual method has no-overrides it lives in its parent's vtable.
2956 if (MethodRange.begin() == MethodRange.end())
2957 BasesWithOverriddenMethods.insert(MD->getParent());
2958 else
2959 Work.insert(MethodRange.begin(), MethodRange.end());
2960 // We've finished processing this element, remove it from the working set.
2961 Work.erase(MD);
2962 }
2963 // For each of our virtual bases, check if it is in the set of overridden
2964 // bases or if it transitively contains a non-virtual base that is.
2965 for (const CXXBaseSpecifier &Base : RD->vbases()) {
2966 const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
2967 if (!HasVtordispSet.count(BaseDecl) &&
2968 RequiresVtordisp(BasesWithOverriddenMethods, BaseDecl))
2969 HasVtordispSet.insert(BaseDecl);
2970 }
2971}
2972
2973/// getASTRecordLayout - Get or compute information about the layout of the
2974/// specified record (struct/union/class), which indicates its size and field
2975/// position information.
2976const ASTRecordLayout &
2977ASTContext::getASTRecordLayout(const RecordDecl *D) const {
2978 // These asserts test different things. A record has a definition
2979 // as soon as we begin to parse the definition. That definition is
2980 // not a complete definition (which is what isDefinition() tests)
2981 // until we *finish* parsing the definition.
2982
2983 if (D->hasExternalLexicalStorage() && !D->getDefinition())
5
Assuming the condition is false
2984 getExternalSource()->CompleteType(const_cast<RecordDecl*>(D));
2985
2986 D = D->getDefinition();
2987 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2987, __PRETTY_FUNCTION__))
;
6
'?' condition is true
2988 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2988, __PRETTY_FUNCTION__))
;
7
Assuming the condition is true
8
'?' condition is true
2989 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2989, __PRETTY_FUNCTION__))
;
9
Assuming the condition is true
10
'?' condition is true
2990
2991 // Look up this layout, if already laid out, return what we have.
2992 // Note that we can't save a reference to the entry because this function
2993 // is recursive.
2994 const ASTRecordLayout *Entry = ASTRecordLayouts[D];
2995 if (Entry) return *Entry;
11
Assuming 'Entry' is null
12
Taking false branch
2996
2997 const ASTRecordLayout *NewEntry = nullptr;
2998
2999 if (isMsLayout(*this)) {
13
Taking false branch
3000 MicrosoftRecordLayoutBuilder Builder(*this);
3001 if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
3002 Builder.cxxLayout(RD);
3003 NewEntry = new (*this) ASTRecordLayout(
3004 *this, Builder.Size, Builder.Alignment, Builder.Alignment,
3005 Builder.RequiredAlignment,
3006 Builder.HasOwnVFPtr, Builder.HasOwnVFPtr || Builder.PrimaryBase,
3007 Builder.VBPtrOffset, Builder.DataSize, Builder.FieldOffsets,
3008 Builder.NonVirtualSize, Builder.Alignment, CharUnits::Zero(),
3009 Builder.PrimaryBase, false, Builder.SharedVBPtrBase,
3010 Builder.EndsWithZeroSizedObject, Builder.LeadsWithZeroSizedBase,
3011 Builder.Bases, Builder.VBases);
3012 } else {
3013 Builder.layout(D);
3014 NewEntry = new (*this) ASTRecordLayout(
3015 *this, Builder.Size, Builder.Alignment, Builder.Alignment,
3016 Builder.RequiredAlignment,
3017 Builder.Size, Builder.FieldOffsets);
3018 }
3019 } else {
3020 if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
14
Taking true branch
3021 EmptySubobjectMap EmptySubobjects(*this, RD);
3022 ItaniumRecordLayoutBuilder Builder(*this, &EmptySubobjects);
3023 Builder.Layout(RD);
15
Calling 'ItaniumRecordLayoutBuilder::Layout'
3024
3025 // In certain situations, we are allowed to lay out objects in the
3026 // tail-padding of base classes. This is ABI-dependent.
3027 // FIXME: this should be stored in the record layout.
3028 bool skipTailPadding =
3029 mustSkipTailPadding(getTargetInfo().getCXXABI(), RD);
3030
3031 // FIXME: This should be done in FinalizeLayout.
3032 CharUnits DataSize =
3033 skipTailPadding ? Builder.getSize() : Builder.getDataSize();
3034 CharUnits NonVirtualSize =
3035 skipTailPadding ? DataSize : Builder.NonVirtualSize;
3036 NewEntry = new (*this) ASTRecordLayout(
3037 *this, Builder.getSize(), Builder.Alignment, Builder.UnadjustedAlignment,
3038 /*RequiredAlignment : used by MS-ABI)*/
3039 Builder.Alignment, Builder.HasOwnVFPtr, RD->isDynamicClass(),
3040 CharUnits::fromQuantity(-1), DataSize, Builder.FieldOffsets,
3041 NonVirtualSize, Builder.NonVirtualAlignment,
3042 EmptySubobjects.SizeOfLargestEmptySubobject, Builder.PrimaryBase,
3043 Builder.PrimaryBaseIsVirtual, nullptr, false, false, Builder.Bases,
3044 Builder.VBases);
3045 } else {
3046 ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3047 Builder.Layout(D);
3048
3049 NewEntry = new (*this) ASTRecordLayout(
3050 *this, Builder.getSize(), Builder.Alignment, Builder.UnadjustedAlignment,
3051 /*RequiredAlignment : used by MS-ABI)*/
3052 Builder.Alignment, Builder.getSize(), Builder.FieldOffsets);
3053 }
3054 }
3055
3056 ASTRecordLayouts[D] = NewEntry;
3057
3058 if (getLangOpts().DumpRecordLayouts) {
3059 llvm::outs() << "\n*** Dumping AST Record Layout\n";
3060 DumpRecordLayout(D, llvm::outs(), getLangOpts().DumpRecordLayoutsSimple);
3061 }
3062
3063 return *NewEntry;
3064}
3065
3066const CXXMethodDecl *ASTContext::getCurrentKeyFunction(const CXXRecordDecl *RD) {
3067 if (!getTargetInfo().getCXXABI().hasKeyFunctions())
3068 return nullptr;
3069
3070 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3070, __PRETTY_FUNCTION__))
;
3071 RD = RD->getDefinition();
3072
3073 // Beware:
3074 // 1) computing the key function might trigger deserialization, which might
3075 // invalidate iterators into KeyFunctions
3076 // 2) 'get' on the LazyDeclPtr might also trigger deserialization and
3077 // invalidate the LazyDeclPtr within the map itself
3078 LazyDeclPtr Entry = KeyFunctions[RD];
3079 const Decl *Result =
3080 Entry ? Entry.get(getExternalSource()) : computeKeyFunction(*this, RD);
3081
3082 // Store it back if it changed.
3083 if (Entry.isOffset() || Entry.isValid() != bool(Result))
3084 KeyFunctions[RD] = const_cast<Decl*>(Result);
3085
3086 return cast_or_null<CXXMethodDecl>(Result);
3087}
3088
3089void ASTContext::setNonKeyFunction(const CXXMethodDecl *Method) {
3090 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3091, __PRETTY_FUNCTION__))
3091 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3091, __PRETTY_FUNCTION__))
;
3092
3093 // Look up the cache entry. Since we're working with the first
3094 // declaration, its parent must be the class definition, which is
3095 // the correct key for the KeyFunctions hash.
3096 const auto &Map = KeyFunctions;
3097 auto I = Map.find(Method->getParent());
3098
3099 // If it's not cached, there's nothing to do.
3100 if (I == Map.end()) return;
3101
3102 // If it is cached, check whether it's the target method, and if so,
3103 // remove it from the cache. Note, the call to 'get' might invalidate
3104 // the iterator and the LazyDeclPtr object within the map.
3105 LazyDeclPtr Ptr = I->second;
3106 if (Ptr.get(getExternalSource()) == Method) {
3107 // FIXME: remember that we did this for module / chained PCH state?
3108 KeyFunctions.erase(Method->getParent());
3109 }
3110}
3111
3112static uint64_t getFieldOffset(const ASTContext &C, const FieldDecl *FD) {
3113 const ASTRecordLayout &Layout = C.getASTRecordLayout(FD->getParent());
4
Calling 'ASTContext::getASTRecordLayout'
3114 return Layout.getFieldOffset(FD->getFieldIndex());
3115}
3116
3117uint64_t ASTContext::getFieldOffset(const ValueDecl *VD) const {
3118 uint64_t OffsetInBits;
3119 if (const FieldDecl *FD = dyn_cast<FieldDecl>(VD)) {
1
Taking false branch
3120 OffsetInBits = ::getFieldOffset(*this, FD);
3121 } else {
3122 const IndirectFieldDecl *IFD = cast<IndirectFieldDecl>(VD);
3123
3124 OffsetInBits = 0;
3125 for (const NamedDecl *ND : IFD->chain())
2
Assuming '__begin2' is not equal to '__end2'
3126 OffsetInBits += ::getFieldOffset(*this, cast<FieldDecl>(ND));
3
Calling 'getFieldOffset'
3127 }
3128
3129 return OffsetInBits;
3130}
3131
3132uint64_t ASTContext::lookupFieldBitOffset(const ObjCInterfaceDecl *OID,
3133 const ObjCImplementationDecl *ID,
3134 const ObjCIvarDecl *Ivar) const {
3135 const ObjCInterfaceDecl *Container = Ivar->getContainingInterface();
3136
3137 // FIXME: We should eliminate the need to have ObjCImplementationDecl passed
3138 // in here; it should never be necessary because that should be the lexical
3139 // decl context for the ivar.
3140
3141 // If we know have an implementation (and the ivar is in it) then
3142 // look up in the implementation layout.
3143 const ASTRecordLayout *RL;
3144 if (ID && declaresSameEntity(ID->getClassInterface(), Container))
3145 RL = &getASTObjCImplementationLayout(ID);
3146 else
3147 RL = &getASTObjCInterfaceLayout(Container);
3148
3149 // Compute field index.
3150 //
3151 // FIXME: The index here is closely tied to how ASTContext::getObjCLayout is
3152 // implemented. This should be fixed to get the information from the layout
3153 // directly.
3154 unsigned Index = 0;
3155
3156 for (const ObjCIvarDecl *IVD = Container->all_declared_ivar_begin();
3157 IVD; IVD = IVD->getNextIvar()) {
3158 if (Ivar == IVD)
3159 break;
3160 ++Index;
3161 }
3162 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3162, __PRETTY_FUNCTION__))
;
3163
3164 return RL->getFieldOffset(Index);
3165}
3166
3167/// getObjCLayout - Get or compute information about the layout of the
3168/// given interface.
3169///
3170/// \param Impl - If given, also include the layout of the interface's
3171/// implementation. This may differ by including synthesized ivars.
3172const ASTRecordLayout &
3173ASTContext::getObjCLayout(const ObjCInterfaceDecl *D,
3174 const ObjCImplementationDecl *Impl) const {
3175 // Retrieve the definition
3176 if (D->hasExternalLexicalStorage() && !D->getDefinition())
3177 getExternalSource()->CompleteType(const_cast<ObjCInterfaceDecl*>(D));
3178 D = D->getDefinition();
3179 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3179, __PRETTY_FUNCTION__))
;
3180
3181 // Look up this layout, if already laid out, return what we have.
3182 const ObjCContainerDecl *Key =
3183 Impl ? (const ObjCContainerDecl*) Impl : (const ObjCContainerDecl*) D;
3184 if (const ASTRecordLayout *Entry = ObjCLayouts[Key])
3185 return *Entry;
3186
3187 // Add in synthesized ivar count if laying out an implementation.
3188 if (Impl) {
3189 unsigned SynthCount = CountNonClassIvars(D);
3190 // If there aren't any synthesized ivars then reuse the interface
3191 // entry. Note we can't cache this because we simply free all
3192 // entries later; however we shouldn't look up implementations
3193 // frequently.
3194 if (SynthCount == 0)
3195 return getObjCLayout(D, nullptr);
3196 }
3197
3198 ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
3199 Builder.Layout(D);
3200
3201 const ASTRecordLayout *NewEntry =
3202 new (*this) ASTRecordLayout(*this, Builder.getSize(),
3203 Builder.Alignment,
3204 Builder.UnadjustedAlignment,
3205 /*RequiredAlignment : used by MS-ABI)*/
3206 Builder.Alignment,
3207 Builder.getDataSize(),
3208 Builder.FieldOffsets);
3209
3210 ObjCLayouts[Key] = NewEntry;
3211
3212 return *NewEntry;
3213}
3214
3215static void PrintOffset(raw_ostream &OS,
3216 CharUnits Offset, unsigned IndentLevel) {
3217 OS << llvm::format("%10" PRId64"l" "d" " | ", (int64_t)Offset.getQuantity());
3218 OS.indent(IndentLevel * 2);
3219}
3220
3221static void PrintBitFieldOffset(raw_ostream &OS, CharUnits Offset,
3222 unsigned Begin, unsigned Width,
3223 unsigned IndentLevel) {
3224 llvm::SmallString<10> Buffer;
3225 {
3226 llvm::raw_svector_ostream BufferOS(Buffer);
3227 BufferOS << Offset.getQuantity() << ':';
3228 if (Width == 0) {
3229 BufferOS << '-';
3230 } else {
3231 BufferOS << Begin << '-' << (Begin + Width - 1);
3232 }
3233 }
3234
3235 OS << llvm::right_justify(Buffer, 10) << " | ";
3236 OS.indent(IndentLevel * 2);
3237}
3238
3239static void PrintIndentNoOffset(raw_ostream &OS, unsigned IndentLevel) {
3240 OS << " | ";
3241 OS.indent(IndentLevel * 2);
3242}
3243
3244static void DumpRecordLayout(raw_ostream &OS, const RecordDecl *RD,
3245 const ASTContext &C,
3246 CharUnits Offset,
3247 unsigned IndentLevel,
3248 const char* Description,
3249 bool PrintSizeInfo,
3250 bool IncludeVirtualBases) {
3251 const ASTRecordLayout &Layout = C.getASTRecordLayout(RD);
3252 auto CXXRD = dyn_cast<CXXRecordDecl>(RD);
3253
3254 PrintOffset(OS, Offset, IndentLevel);
3255 OS << C.getTypeDeclType(const_cast<RecordDecl*>(RD)).getAsString();
3256 if (Description)
3257 OS << ' ' << Description;
3258 if (CXXRD && CXXRD->isEmpty())
3259 OS << " (empty)";
3260 OS << '\n';
3261
3262 IndentLevel++;
3263
3264 // Dump bases.
3265 if (CXXRD) {
3266 const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
3267 bool HasOwnVFPtr = Layout.hasOwnVFPtr();
3268 bool HasOwnVBPtr = Layout.hasOwnVBPtr();
3269
3270 // Vtable pointer.
3271 if (CXXRD->isDynamicClass() && !PrimaryBase && !isMsLayout(C)) {
3272 PrintOffset(OS, Offset, IndentLevel);
3273 OS << '(' << *RD << " vtable pointer)\n";
3274 } else if (HasOwnVFPtr) {
3275 PrintOffset(OS, Offset, IndentLevel);
3276 // vfptr (for Microsoft C++ ABI)
3277 OS << '(' << *RD << " vftable pointer)\n";
3278 }
3279
3280 // Collect nvbases.
3281 SmallVector<const CXXRecordDecl *, 4> Bases;
3282 for (const CXXBaseSpecifier &Base : CXXRD->bases()) {
3283 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3284, __PRETTY_FUNCTION__))
3284 "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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3284, __PRETTY_FUNCTION__))
;
3285 if (!Base.isVirtual())
3286 Bases.push_back(Base.getType()->getAsCXXRecordDecl());
3287 }
3288
3289 // Sort nvbases by offset.
3290 std::stable_sort(Bases.begin(), Bases.end(),
3291 [&](const CXXRecordDecl *L, const CXXRecordDecl *R) {
3292 return Layout.getBaseClassOffset(L) < Layout.getBaseClassOffset(R);
3293 });
3294
3295 // Dump (non-virtual) bases
3296 for (const CXXRecordDecl *Base : Bases) {
3297 CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base);
3298 DumpRecordLayout(OS, Base, C, BaseOffset, IndentLevel,
3299 Base == PrimaryBase ? "(primary base)" : "(base)",
3300 /*PrintSizeInfo=*/false,
3301 /*IncludeVirtualBases=*/false);
3302 }
3303
3304 // vbptr (for Microsoft C++ ABI)
3305 if (HasOwnVBPtr) {
3306 PrintOffset(OS, Offset + Layout.getVBPtrOffset(), IndentLevel);
3307 OS << '(' << *RD << " vbtable pointer)\n";
3308 }
3309 }
3310
3311 // Dump fields.
3312 uint64_t FieldNo = 0;
3313 for (RecordDecl::field_iterator I = RD->field_begin(),
3314 E = RD->field_end(); I != E; ++I, ++FieldNo) {
3315 const FieldDecl &Field = **I;
3316 uint64_t LocalFieldOffsetInBits = Layout.getFieldOffset(FieldNo);
3317 CharUnits FieldOffset =
3318 Offset + C.toCharUnitsFromBits(LocalFieldOffsetInBits);
3319
3320 // Recursively dump fields of record type.
3321 if (auto RT = Field.getType()->getAs<RecordType>()) {
3322 DumpRecordLayout(OS, RT->getDecl(), C, FieldOffset, IndentLevel,
3323 Field.getName().data(),
3324 /*PrintSizeInfo=*/false,
3325 /*IncludeVirtualBases=*/true);
3326 continue;
3327 }
3328
3329 if (Field.isBitField()) {
3330 uint64_t LocalFieldByteOffsetInBits = C.toBits(FieldOffset - Offset);
3331 unsigned Begin = LocalFieldOffsetInBits - LocalFieldByteOffsetInBits;
3332 unsigned Width = Field.getBitWidthValue(C);
3333 PrintBitFieldOffset(OS, FieldOffset, Begin, Width, IndentLevel);
3334 } else {
3335 PrintOffset(OS, FieldOffset, IndentLevel);
3336 }
3337 OS << Field.getType().getAsString() << ' ' << Field << '\n';
3338 }
3339
3340 // Dump virtual bases.
3341 if (CXXRD && IncludeVirtualBases) {
3342 const ASTRecordLayout::VBaseOffsetsMapTy &VtorDisps =
3343 Layout.getVBaseOffsetsMap();
3344
3345 for (const CXXBaseSpecifier &Base : CXXRD->vbases()) {
3346 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-9~svn358860/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3346, __PRETTY_FUNCTION__))
;
3347 const CXXRecordDecl *VBase = Base.getType()->getAsCXXRecordDecl();
3348
3349 CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBase);
3350
3351 if (VtorDisps.find(VBase)->second.hasVtorDisp()) {
3352 PrintOffset(OS, VBaseOffset - CharUnits::fromQuantity(4), IndentLevel);
3353 OS << "(vtordisp for vbase " << *VBase << ")\n";
3354 }
3355
3356 DumpRecordLayout(OS, VBase, C, VBaseOffset, IndentLevel,
3357 VBase == Layout.getPrimaryBase() ?
3358 "(primary virtual base)" : "(virtual base)",
3359 /*PrintSizeInfo=*/false,
3360 /*IncludeVirtualBases=*/false);
3361 }
3362 }
3363
3364 if (!PrintSizeInfo) return;
3365
3366 PrintIndentNoOffset(OS, IndentLevel - 1);
3367 OS << "[sizeof=" << Layout.getSize().getQuantity();
3368 if (CXXRD && !isMsLayout(C))
3369 OS << ", dsize=" << Layout.getDataSize().getQuantity();
3370 OS << ", align=" << Layout.getAlignment().getQuantity();
3371
3372 if (CXXRD) {
3373 OS << ",\n";
3374 PrintIndentNoOffset(OS, IndentLevel - 1);
3375 OS << " nvsize=" << Layout.getNonVirtualSize().getQuantity();
3376 OS << ", nvalign=" << Layout.getNonVirtualAlignment().getQuantity();
3377 }
3378 OS << "]\n";
3379}
3380
3381void ASTContext::DumpRecordLayout(const RecordDecl *RD,
3382 raw_ostream &OS,
3383 bool Simple) const {
3384 if (!Simple) {
3385 ::DumpRecordLayout(OS, RD, *this, CharUnits(), 0, nullptr,
3386 /*PrintSizeInfo*/true,
3387 /*IncludeVirtualBases=*/true);
3388 return;
3389 }
3390
3391 // The "simple" format is designed to be parsed by the
3392 // layout-override testing code. There shouldn't be any external
3393 // uses of this format --- when LLDB overrides a layout, it sets up
3394 // the data structures directly --- so feel free to adjust this as
3395 // you like as long as you also update the rudimentary parser for it
3396 // in libFrontend.
3397
3398 const ASTRecordLayout &Info = getASTRecordLayout(RD);
3399 OS << "Type: " << getTypeDeclType(RD).getAsString() << "\n";
3400 OS << "\nLayout: ";
3401 OS << "<ASTRecordLayout\n";
3402 OS << " Size:" << toBits(Info.getSize()) << "\n";
3403 if (!isMsLayout(*this))
3404 OS << " DataSize:" << toBits(Info.getDataSize()) << "\n";
3405 OS << " Alignment:" << toBits(Info.getAlignment()) << "\n";
3406 OS << " FieldOffsets: [";
3407 for (unsigned i = 0, e = Info.getFieldCount(); i != e; ++i) {
3408 if (i) OS << ", ";
3409 OS << Info.getFieldOffset(i);
3410 }
3411 OS << "]>\n";
3412}