1//===--- CGClass.cpp - Emit LLVM Code for C++ classes -----------*- C++ -*-===//
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// This contains code dealing with C++ code generation of classes
10//
11//===----------------------------------------------------------------------===//
12
13#include "CGBlocks.h"
14#include "CGCXXABI.h"
15#include "CGDebugInfo.h"
16#include "CGRecordLayout.h"
17#include "CodeGenFunction.h"
18#include "TargetInfo.h"
19#include "clang/AST/Attr.h"
20#include "clang/AST/CXXInheritance.h"
21#include "clang/AST/CharUnits.h"
22#include "clang/AST/DeclTemplate.h"
23#include "clang/AST/EvaluatedExprVisitor.h"
24#include "clang/AST/RecordLayout.h"
25#include "clang/AST/StmtCXX.h"
26#include "clang/Basic/CodeGenOptions.h"
27#include "clang/Basic/TargetBuiltins.h"
28#include "clang/CodeGen/CGFunctionInfo.h"
29#include "llvm/IR/Intrinsics.h"
30#include "llvm/IR/Metadata.h"
31#include "llvm/Transforms/Utils/SanitizerStats.h"
32
33using namespace clang;
34using namespace CodeGen;
35
36/// Return the best known alignment for an unknown pointer to a
37/// particular class.
38CharUnits CodeGenModule::getClassPointerAlignment(const CXXRecordDecl *RD) {
39 if (!RD->hasDefinition())
40 return CharUnits::One(); // Hopefully won't be used anywhere.
41
42 auto &layout = getContext().getASTRecordLayout(RD);
43
44 // If the class is final, then we know that the pointer points to an
45 // object of that type and can use the full alignment.
46 if (RD->isEffectivelyFinal())
47 return layout.getAlignment();
48
49 // Otherwise, we have to assume it could be a subclass.
50 return layout.getNonVirtualAlignment();
51}
52
53/// Return the smallest possible amount of storage that might be allocated
54/// starting from the beginning of an object of a particular class.
55///
56/// This may be smaller than sizeof(RD) if RD has virtual base classes.
57CharUnits CodeGenModule::getMinimumClassObjectSize(const CXXRecordDecl *RD) {
58 if (!RD->hasDefinition())
59 return CharUnits::One();
60
61 auto &layout = getContext().getASTRecordLayout(RD);
62
63 // If the class is final, then we know that the pointer points to an
64 // object of that type and can use the full alignment.
65 if (RD->isEffectivelyFinal())
66 return layout.getSize();
67
68 // Otherwise, we have to assume it could be a subclass.
69 return std::max(layout.getNonVirtualSize(), CharUnits::One());
70}
71
72/// Return the best known alignment for a pointer to a virtual base,
73/// given the alignment of a pointer to the derived class.
74CharUnits CodeGenModule::getVBaseAlignment(CharUnits actualDerivedAlign,
75 const CXXRecordDecl *derivedClass,
76 const CXXRecordDecl *vbaseClass) {
77 // The basic idea here is that an underaligned derived pointer might
78 // indicate an underaligned base pointer.
79
80 assert(vbaseClass->isCompleteDefinition());
81 auto &baseLayout = getContext().getASTRecordLayout(vbaseClass);
82 CharUnits expectedVBaseAlign = baseLayout.getNonVirtualAlignment();
83
84 return getDynamicOffsetAlignment(actualDerivedAlign, derivedClass,
85 expectedVBaseAlign);
86}
87
88CharUnits
89CodeGenModule::getDynamicOffsetAlignment(CharUnits actualBaseAlign,
90 const CXXRecordDecl *baseDecl,
91 CharUnits expectedTargetAlign) {
92 // If the base is an incomplete type (which is, alas, possible with
93 // member pointers), be pessimistic.
94 if (!baseDecl->isCompleteDefinition())
95 return std::min(actualBaseAlign, expectedTargetAlign);
96
97 auto &baseLayout = getContext().getASTRecordLayout(baseDecl);
98 CharUnits expectedBaseAlign = baseLayout.getNonVirtualAlignment();
99
100 // If the class is properly aligned, assume the target offset is, too.
101 //
102 // This actually isn't necessarily the right thing to do --- if the
103 // class is a complete object, but it's only properly aligned for a
104 // base subobject, then the alignments of things relative to it are
105 // probably off as well. (Note that this requires the alignment of
106 // the target to be greater than the NV alignment of the derived
107 // class.)
108 //
109 // However, our approach to this kind of under-alignment can only
110 // ever be best effort; after all, we're never going to propagate
111 // alignments through variables or parameters. Note, in particular,
112 // that constructing a polymorphic type in an address that's less
113 // than pointer-aligned will generally trap in the constructor,
114 // unless we someday add some sort of attribute to change the
115 // assumed alignment of 'this'. So our goal here is pretty much
116 // just to allow the user to explicitly say that a pointer is
117 // under-aligned and then safely access its fields and vtables.
118 if (actualBaseAlign >= expectedBaseAlign) {
119 return expectedTargetAlign;
120 }
121
122 // Otherwise, we might be offset by an arbitrary multiple of the
123 // actual alignment. The correct adjustment is to take the min of
124 // the two alignments.
125 return std::min(actualBaseAlign, expectedTargetAlign);
126}
127
128Address CodeGenFunction::LoadCXXThisAddress() {
129 assert(CurFuncDecl && "loading 'this' without a func declaration?");
130 assert(isa<CXXMethodDecl>(CurFuncDecl));
131
132 // Lazily compute CXXThisAlignment.
133 if (CXXThisAlignment.isZero()) {
134 // Just use the best known alignment for the parent.
135 // TODO: if we're currently emitting a complete-object ctor/dtor,
136 // we can always use the complete-object alignment.
137 auto RD = cast<CXXMethodDecl>(CurFuncDecl)->getParent();
138 CXXThisAlignment = CGM.getClassPointerAlignment(RD);
139 }
140
141 return Address(LoadCXXThis(), CXXThisAlignment);
142}
143
144/// Emit the address of a field using a member data pointer.
145///
146/// \param E Only used for emergency diagnostics
147Address
148CodeGenFunction::EmitCXXMemberDataPointerAddress(const Expr *E, Address base,
149 llvm::Value *memberPtr,
150 const MemberPointerType *memberPtrType,
151 LValueBaseInfo *BaseInfo,
152 TBAAAccessInfo *TBAAInfo) {
153 // Ask the ABI to compute the actual address.
154 llvm::Value *ptr =
155 CGM.getCXXABI().EmitMemberDataPointerAddress(*this, E, base,
156 memberPtr, memberPtrType);
157
158 QualType memberType = memberPtrType->getPointeeType();
159 CharUnits memberAlign =
160 CGM.getNaturalTypeAlignment(memberType, BaseInfo, TBAAInfo);
161 memberAlign =
162 CGM.getDynamicOffsetAlignment(base.getAlignment(),
163 memberPtrType->getClass()->getAsCXXRecordDecl(),
164 memberAlign);
165 return Address(ptr, memberAlign);
166}
167
168CharUnits CodeGenModule::computeNonVirtualBaseClassOffset(
169 const CXXRecordDecl *DerivedClass, CastExpr::path_const_iterator Start,
170 CastExpr::path_const_iterator End) {
171 CharUnits Offset = CharUnits::Zero();
172
173 const ASTContext &Context = getContext();
174 const CXXRecordDecl *RD = DerivedClass;
175
176 for (CastExpr::path_const_iterator I = Start; I != End; ++I) {
177 const CXXBaseSpecifier *Base = *I;
178 assert(!Base->isVirtual() && "Should not see virtual bases here!");
179
180 // Get the layout.
181 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
182
183 const auto *BaseDecl =
184 cast<CXXRecordDecl>(Base->getType()->castAs<RecordType>()->getDecl());
185
186 // Add the offset.
187 Offset += Layout.getBaseClassOffset(BaseDecl);
188
189 RD = BaseDecl;
190 }
191
192 return Offset;
193}
194
195llvm::Constant *
196CodeGenModule::GetNonVirtualBaseClassOffset(const CXXRecordDecl *ClassDecl,
197 CastExpr::path_const_iterator PathBegin,
198 CastExpr::path_const_iterator PathEnd) {
199 assert(PathBegin != PathEnd && "Base path should not be empty!");
200
201 CharUnits Offset =
202 computeNonVirtualBaseClassOffset(ClassDecl, PathBegin, PathEnd);
203 if (Offset.isZero())
204 return nullptr;
205
206 llvm::Type *PtrDiffTy =
207 Types.ConvertType(getContext().getPointerDiffType());
208
209 return llvm::ConstantInt::get(PtrDiffTy, Offset.getQuantity());
210}
211
212/// Gets the address of a direct base class within a complete object.
213/// This should only be used for (1) non-virtual bases or (2) virtual bases
214/// when the type is known to be complete (e.g. in complete destructors).
215///
216/// The object pointed to by 'This' is assumed to be non-null.
217Address
218CodeGenFunction::GetAddressOfDirectBaseInCompleteClass(Address This,
219 const CXXRecordDecl *Derived,
220 const CXXRecordDecl *Base,
221 bool BaseIsVirtual) {
222 // 'this' must be a pointer (in some address space) to Derived.
223 assert(This.getElementType() == ConvertType(Derived));
224
225 // Compute the offset of the virtual base.
226 CharUnits Offset;
227 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(Derived);
228 if (BaseIsVirtual)
229 Offset = Layout.getVBaseClassOffset(Base);
230 else
231 Offset = Layout.getBaseClassOffset(Base);
232
233 // Shift and cast down to the base type.
234 // TODO: for complete types, this should be possible with a GEP.
235 Address V = This;
236 if (!Offset.isZero()) {
237 V = Builder.CreateElementBitCast(V, Int8Ty);
238 V = Builder.CreateConstInBoundsByteGEP(V, Offset);
239 }
240 V = Builder.CreateElementBitCast(V, ConvertType(Base));
241
242 return V;
243}
244
245static Address
246ApplyNonVirtualAndVirtualOffset(CodeGenFunction &CGF, Address addr,
247 CharUnits nonVirtualOffset,
248 llvm::Value *virtualOffset,
249 const CXXRecordDecl *derivedClass,
250 const CXXRecordDecl *nearestVBase) {
251 // Assert that we have something to do.
252 assert(!nonVirtualOffset.isZero() || virtualOffset != nullptr);
253
254 // Compute the offset from the static and dynamic components.
255 llvm::Value *baseOffset;
256 if (!nonVirtualOffset.isZero()) {
257 llvm::Type *OffsetType =
258 (CGF.CGM.getTarget().getCXXABI().isItaniumFamily() &&
259 CGF.CGM.getItaniumVTableContext().isRelativeLayout())
260 ? CGF.Int32Ty
261 : CGF.PtrDiffTy;
262 baseOffset =
263 llvm::ConstantInt::get(OffsetType, nonVirtualOffset.getQuantity());
264 if (virtualOffset) {
265 baseOffset = CGF.Builder.CreateAdd(virtualOffset, baseOffset);
266 }
267 } else {
268 baseOffset = virtualOffset;
269 }
270
271 // Apply the base offset.
272 llvm::Value *ptr = addr.getPointer();
273 unsigned AddrSpace = ptr->getType()->getPointerAddressSpace();
274 ptr = CGF.Builder.CreateBitCast(ptr, CGF.Int8Ty->getPointerTo(AddrSpace));
275 ptr = CGF.Builder.CreateInBoundsGEP(CGF.Int8Ty, ptr, baseOffset, "add.ptr");
276
277 // If we have a virtual component, the alignment of the result will
278 // be relative only to the known alignment of that vbase.
279 CharUnits alignment;
280 if (virtualOffset) {
281 assert(nearestVBase && "virtual offset without vbase?");
282 alignment = CGF.CGM.getVBaseAlignment(addr.getAlignment(),
283 derivedClass, nearestVBase);
284 } else {
285 alignment = addr.getAlignment();
286 }
287 alignment = alignment.alignmentAtOffset(nonVirtualOffset);
288
289 return Address(ptr, alignment);
290}
291
292Address CodeGenFunction::GetAddressOfBaseClass(
293 Address Value, const CXXRecordDecl *Derived,
294 CastExpr::path_const_iterator PathBegin,
295 CastExpr::path_const_iterator PathEnd, bool NullCheckValue,
296 SourceLocation Loc) {
297 assert(PathBegin != PathEnd && "Base path should not be empty!");
298
299 CastExpr::path_const_iterator Start = PathBegin;
300 const CXXRecordDecl *VBase = nullptr;
301
302 // Sema has done some convenient canonicalization here: if the
303 // access path involved any virtual steps, the conversion path will
304 // *start* with a step down to the correct virtual base subobject,
305 // and hence will not require any further steps.
306 if ((*Start)->isVirtual()) {
307 VBase = cast<CXXRecordDecl>(
308 (*Start)->getType()->castAs<RecordType>()->getDecl());
309 ++Start;
310 }
311
312 // Compute the static offset of the ultimate destination within its
313 // allocating subobject (the virtual base, if there is one, or else
314 // the "complete" object that we see).
315 CharUnits NonVirtualOffset = CGM.computeNonVirtualBaseClassOffset(
316 VBase ? VBase : Derived, Start, PathEnd);
317
318 // If there's a virtual step, we can sometimes "devirtualize" it.
319 // For now, that's limited to when the derived type is final.
320 // TODO: "devirtualize" this for accesses to known-complete objects.
321 if (VBase && Derived->hasAttr<FinalAttr>()) {
322 const ASTRecordLayout &layout = getContext().getASTRecordLayout(Derived);
323 CharUnits vBaseOffset = layout.getVBaseClassOffset(VBase);
324 NonVirtualOffset += vBaseOffset;
325 VBase = nullptr; // we no longer have a virtual step
326 }
327
328 // Get the base pointer type.
329 llvm::Type *BasePtrTy =
330 ConvertType((PathEnd[-1])->getType())
331 ->getPointerTo(Value.getType()->getPointerAddressSpace());
332
333 QualType DerivedTy = getContext().getRecordType(Derived);
334 CharUnits DerivedAlign = CGM.getClassPointerAlignment(Derived);
335
336 // If the static offset is zero and we don't have a virtual step,
337 // just do a bitcast; null checks are unnecessary.
338 if (NonVirtualOffset.isZero() && !VBase) {
339 if (sanitizePerformTypeCheck()) {
340 SanitizerSet SkippedChecks;
341 SkippedChecks.set(SanitizerKind::Null, !NullCheckValue);
342 EmitTypeCheck(TCK_Upcast, Loc, Value.getPointer(),
343 DerivedTy, DerivedAlign, SkippedChecks);
344 }
345 return Builder.CreateBitCast(Value, BasePtrTy);
346 }
347
348 llvm::BasicBlock *origBB = nullptr;
349 llvm::BasicBlock *endBB = nullptr;
350
351 // Skip over the offset (and the vtable load) if we're supposed to
352 // null-check the pointer.
353 if (NullCheckValue) {
354 origBB = Builder.GetInsertBlock();
355 llvm::BasicBlock *notNullBB = createBasicBlock("cast.notnull");
356 endBB = createBasicBlock("cast.end");
357
358 llvm::Value *isNull = Builder.CreateIsNull(Value.getPointer());
359 Builder.CreateCondBr(isNull, endBB, notNullBB);
360 EmitBlock(notNullBB);
361 }
362
363 if (sanitizePerformTypeCheck()) {
364 SanitizerSet SkippedChecks;
365 SkippedChecks.set(SanitizerKind::Null, true);
366 EmitTypeCheck(VBase ? TCK_UpcastToVirtualBase : TCK_Upcast, Loc,
367 Value.getPointer(), DerivedTy, DerivedAlign, SkippedChecks);
368 }
369
370 // Compute the virtual offset.
371 llvm::Value *VirtualOffset = nullptr;
372 if (VBase) {
373 VirtualOffset =
374 CGM.getCXXABI().GetVirtualBaseClassOffset(*this, Value, Derived, VBase);
375 }
376
377 // Apply both offsets.
378 Value = ApplyNonVirtualAndVirtualOffset(*this, Value, NonVirtualOffset,
379 VirtualOffset, Derived, VBase);
380
381 // Cast to the destination type.
382 Value = Builder.CreateBitCast(Value, BasePtrTy);
383
384 // Build a phi if we needed a null check.
385 if (NullCheckValue) {
386 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
387 Builder.CreateBr(endBB);
388 EmitBlock(endBB);
389
390 llvm::PHINode *PHI = Builder.CreatePHI(BasePtrTy, 2, "cast.result");
391 PHI->addIncoming(Value.getPointer(), notNullBB);
392 PHI->addIncoming(llvm::Constant::getNullValue(BasePtrTy), origBB);
393 Value = Address(PHI, Value.getAlignment());
394 }
395
396 return Value;
397}
398
399Address
400CodeGenFunction::GetAddressOfDerivedClass(Address BaseAddr,
401 const CXXRecordDecl *Derived,
402 CastExpr::path_const_iterator PathBegin,
403 CastExpr::path_const_iterator PathEnd,
404 bool NullCheckValue) {
405 assert(PathBegin != PathEnd && "Base path should not be empty!");
406
407 QualType DerivedTy =
408 getContext().getCanonicalType(getContext().getTagDeclType(Derived));
409 unsigned AddrSpace =
410 BaseAddr.getPointer()->getType()->getPointerAddressSpace();
411 llvm::Type *DerivedPtrTy = ConvertType(DerivedTy)->getPointerTo(AddrSpace);
412
413 llvm::Value *NonVirtualOffset =
414 CGM.GetNonVirtualBaseClassOffset(Derived, PathBegin, PathEnd);
415
416 if (!NonVirtualOffset) {
417 // No offset, we can just cast back.
418 return Builder.CreateBitCast(BaseAddr, DerivedPtrTy);
419 }
420
421 llvm::BasicBlock *CastNull = nullptr;
422 llvm::BasicBlock *CastNotNull = nullptr;
423 llvm::BasicBlock *CastEnd = nullptr;
424
425 if (NullCheckValue) {
426 CastNull = createBasicBlock("cast.null");
427 CastNotNull = createBasicBlock("cast.notnull");
428 CastEnd = createBasicBlock("cast.end");
429
430 llvm::Value *IsNull = Builder.CreateIsNull(BaseAddr.getPointer());
431 Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
432 EmitBlock(CastNotNull);
433 }
434
435 // Apply the offset.
436 llvm::Value *Value = Builder.CreateBitCast(BaseAddr.getPointer(), Int8PtrTy);
437 Value = Builder.CreateInBoundsGEP(
438 Int8Ty, Value, Builder.CreateNeg(NonVirtualOffset), "sub.ptr");
439
440 // Just cast.
441 Value = Builder.CreateBitCast(Value, DerivedPtrTy);
442
443 // Produce a PHI if we had a null-check.
444 if (NullCheckValue) {
445 Builder.CreateBr(CastEnd);
446 EmitBlock(CastNull);
447 Builder.CreateBr(CastEnd);
448 EmitBlock(CastEnd);
449
450 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
451 PHI->addIncoming(Value, CastNotNull);
452 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull);
453 Value = PHI;
454 }
455
456 return Address(Value, CGM.getClassPointerAlignment(Derived));
457}
458
459llvm::Value *CodeGenFunction::GetVTTParameter(GlobalDecl GD,
460 bool ForVirtualBase,
461 bool Delegating) {
462 if (!CGM.getCXXABI().NeedsVTTParameter(GD)) {
463 // This constructor/destructor does not need a VTT parameter.
464 return nullptr;
465 }
466
467 const CXXRecordDecl *RD = cast<CXXMethodDecl>(CurCodeDecl)->getParent();
468 const CXXRecordDecl *Base = cast<CXXMethodDecl>(GD.getDecl())->getParent();
469
470 llvm::Value *VTT;
471
472 uint64_t SubVTTIndex;
473
474 if (Delegating) {
475 // If this is a delegating constructor call, just load the VTT.
476 return LoadCXXVTT();
477 } else if (RD == Base) {
478 // If the record matches the base, this is the complete ctor/dtor
479 // variant calling the base variant in a class with virtual bases.
480 assert(!CGM.getCXXABI().NeedsVTTParameter(CurGD) &&
481 "doing no-op VTT offset in base dtor/ctor?");
482 assert(!ForVirtualBase && "Can't have same class as virtual base!");
483 SubVTTIndex = 0;
484 } else {
485 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
486 CharUnits BaseOffset = ForVirtualBase ?
487 Layout.getVBaseClassOffset(Base) :
488 Layout.getBaseClassOffset(Base);
489
490 SubVTTIndex =
491 CGM.getVTables().getSubVTTIndex(RD, BaseSubobject(Base, BaseOffset));
492 assert(SubVTTIndex != 0 && "Sub-VTT index must be greater than zero!");
493 }
494
495 if (CGM.getCXXABI().NeedsVTTParameter(CurGD)) {
496 // A VTT parameter was passed to the constructor, use it.
497 VTT = LoadCXXVTT();
498 VTT = Builder.CreateConstInBoundsGEP1_64(VTT, SubVTTIndex);
499 } else {
500 // We're the complete constructor, so get the VTT by name.
501 VTT = CGM.getVTables().GetAddrOfVTT(RD);
502 VTT = Builder.CreateConstInBoundsGEP2_64(VTT, 0, SubVTTIndex);
503 }
504
505 return VTT;
506}
507
508namespace {
509 /// Call the destructor for a direct base class.
510 struct CallBaseDtor final : EHScopeStack::Cleanup {
511 const CXXRecordDecl *BaseClass;
512 bool BaseIsVirtual;
513 CallBaseDtor(const CXXRecordDecl *Base, bool BaseIsVirtual)
514 : BaseClass(Base), BaseIsVirtual(BaseIsVirtual) {}
515
516 void Emit(CodeGenFunction &CGF, Flags flags) override {
517 const CXXRecordDecl *DerivedClass =
518 cast<CXXMethodDecl>(CGF.CurCodeDecl)->getParent();
519
520 const CXXDestructorDecl *D = BaseClass->getDestructor();
521 // We are already inside a destructor, so presumably the object being
522 // destroyed should have the expected type.
523 QualType ThisTy = D->getThisObjectType();
524 Address Addr =
525 CGF.GetAddressOfDirectBaseInCompleteClass(CGF.LoadCXXThisAddress(),
526 DerivedClass, BaseClass,
527 BaseIsVirtual);
528 CGF.EmitCXXDestructorCall(D, Dtor_Base, BaseIsVirtual,
529 /*Delegating=*/false, Addr, ThisTy);
530 }
531 };
532
533 /// A visitor which checks whether an initializer uses 'this' in a
534 /// way which requires the vtable to be properly set.
535 struct DynamicThisUseChecker : ConstEvaluatedExprVisitor<DynamicThisUseChecker> {
536 typedef ConstEvaluatedExprVisitor<DynamicThisUseChecker> super;
537
538 bool UsesThis;
539
540 DynamicThisUseChecker(const ASTContext &C) : super(C), UsesThis(false) {}
541
542 // Black-list all explicit and implicit references to 'this'.
543 //
544 // Do we need to worry about external references to 'this' derived
545 // from arbitrary code? If so, then anything which runs arbitrary
546 // external code might potentially access the vtable.
547 void VisitCXXThisExpr(const CXXThisExpr *E) { UsesThis = true; }
548 };
549} // end anonymous namespace
550
551static bool BaseInitializerUsesThis(ASTContext &C, const Expr *Init) {
552 DynamicThisUseChecker Checker(C);
553 Checker.Visit(Init);
554 return Checker.UsesThis;
555}
556
557static void EmitBaseInitializer(CodeGenFunction &CGF,
558 const CXXRecordDecl *ClassDecl,
559 CXXCtorInitializer *BaseInit) {
560 assert(BaseInit->isBaseInitializer() &&
561 "Must have base initializer!");
562
563 Address ThisPtr = CGF.LoadCXXThisAddress();
564
565 const Type *BaseType = BaseInit->getBaseClass();
566 const auto *BaseClassDecl =
567 cast<CXXRecordDecl>(BaseType->castAs<RecordType>()->getDecl());
568
569 bool isBaseVirtual = BaseInit->isBaseVirtual();
570
571 // If the initializer for the base (other than the constructor
572 // itself) accesses 'this' in any way, we need to initialize the
573 // vtables.
574 if (BaseInitializerUsesThis(CGF.getContext(), BaseInit->getInit()))
575 CGF.InitializeVTablePointers(ClassDecl);
576
577 // We can pretend to be a complete class because it only matters for
578 // virtual bases, and we only do virtual bases for complete ctors.
579 Address V =
580 CGF.GetAddressOfDirectBaseInCompleteClass(ThisPtr, ClassDecl,
581 BaseClassDecl,
582 isBaseVirtual);
583 AggValueSlot AggSlot =
584 AggValueSlot::forAddr(
585 V, Qualifiers(),
586 AggValueSlot::IsDestructed,
587 AggValueSlot::DoesNotNeedGCBarriers,
588 AggValueSlot::IsNotAliased,
589 CGF.getOverlapForBaseInit(ClassDecl, BaseClassDecl, isBaseVirtual));
590
591 CGF.EmitAggExpr(BaseInit->getInit(), AggSlot);
592
593 if (CGF.CGM.getLangOpts().Exceptions &&
594 !BaseClassDecl->hasTrivialDestructor())
595 CGF.EHStack.pushCleanup<CallBaseDtor>(EHCleanup, BaseClassDecl,
596 isBaseVirtual);
597}
598
599static bool isMemcpyEquivalentSpecialMember(const CXXMethodDecl *D) {
600 auto *CD = dyn_cast<CXXConstructorDecl>(D);
601 if (!(CD && CD->isCopyOrMoveConstructor()) &&
602 !D->isCopyAssignmentOperator() && !D->isMoveAssignmentOperator())
603 return false;
604
605 // We can emit a memcpy for a trivial copy or move constructor/assignment.
606 if (D->isTrivial() && !D->getParent()->mayInsertExtraPadding())
607 return true;
608
609 // We *must* emit a memcpy for a defaulted union copy or move op.
610 if (D->getParent()->isUnion() && D->isDefaulted())
611 return true;
612
613 return false;
614}
615
616static void EmitLValueForAnyFieldInitialization(CodeGenFunction &CGF,
617 CXXCtorInitializer *MemberInit,
618 LValue &LHS) {
619 FieldDecl *Field = MemberInit->getAnyMember();
620 if (MemberInit->isIndirectMemberInitializer()) {
621 // If we are initializing an anonymous union field, drill down to the field.
622 IndirectFieldDecl *IndirectField = MemberInit->getIndirectMember();
623 for (const auto *I : IndirectField->chain())
624 LHS = CGF.EmitLValueForFieldInitialization(LHS, cast<FieldDecl>(I));
625 } else {
626 LHS = CGF.EmitLValueForFieldInitialization(LHS, Field);
627 }
628}
629
630static void EmitMemberInitializer(CodeGenFunction &CGF,
631 const CXXRecordDecl *ClassDecl,
632 CXXCtorInitializer *MemberInit,
633 const CXXConstructorDecl *Constructor,
634 FunctionArgList &Args) {
635 ApplyDebugLocation Loc(CGF, MemberInit->getSourceLocation());
636 assert(MemberInit->isAnyMemberInitializer() &&
637 "Must have member initializer!");
638 assert(MemberInit->getInit() && "Must have initializer!");
639
640 // non-static data member initializers.
641 FieldDecl *Field = MemberInit->getAnyMember();
642 QualType FieldType = Field->getType();
643
644 llvm::Value *ThisPtr = CGF.LoadCXXThis();
645 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
646 LValue LHS;
647
648 // If a base constructor is being emitted, create an LValue that has the
649 // non-virtual alignment.
650 if (CGF.CurGD.getCtorType() == Ctor_Base)
651 LHS = CGF.MakeNaturalAlignPointeeAddrLValue(ThisPtr, RecordTy);
652 else
653 LHS = CGF.MakeNaturalAlignAddrLValue(ThisPtr, RecordTy);
654
655 EmitLValueForAnyFieldInitialization(CGF, MemberInit, LHS);
656
657 // Special case: if we are in a copy or move constructor, and we are copying
658 // an array of PODs or classes with trivial copy constructors, ignore the
659 // AST and perform the copy we know is equivalent.
660 // FIXME: This is hacky at best... if we had a bit more explicit information
661 // in the AST, we could generalize it more easily.
662 const ConstantArrayType *Array
663 = CGF.getContext().getAsConstantArrayType(FieldType);
664 if (Array && Constructor->isDefaulted() &&
665 Constructor->isCopyOrMoveConstructor()) {
666 QualType BaseElementTy = CGF.getContext().getBaseElementType(Array);
667 CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit());
668 if (BaseElementTy.isPODType(CGF.getContext()) ||
669 (CE && isMemcpyEquivalentSpecialMember(CE->getConstructor()))) {
670 unsigned SrcArgIndex =
671 CGF.CGM.getCXXABI().getSrcArgforCopyCtor(Constructor, Args);
672 llvm::Value *SrcPtr
673 = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(Args[SrcArgIndex]));
674 LValue ThisRHSLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy);
675 LValue Src = CGF.EmitLValueForFieldInitialization(ThisRHSLV, Field);
676
677 // Copy the aggregate.
678 CGF.EmitAggregateCopy(LHS, Src, FieldType, CGF.getOverlapForFieldInit(Field),
679 LHS.isVolatileQualified());
680 // Ensure that we destroy the objects if an exception is thrown later in
681 // the constructor.
682 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
683 if (CGF.needsEHCleanup(dtorKind))
684 CGF.pushEHDestroy(dtorKind, LHS.getAddress(CGF), FieldType);
685 return;
686 }
687 }
688
689 CGF.EmitInitializerForField(Field, LHS, MemberInit->getInit());
690}
691
692void CodeGenFunction::EmitInitializerForField(FieldDecl *Field, LValue LHS,
693 Expr *Init) {
694 QualType FieldType = Field->getType();
695 switch (getEvaluationKind(FieldType)) {
696 case TEK_Scalar:
697 if (LHS.isSimple()) {
698 EmitExprAsInit(Init, Field, LHS, false);
699 } else {
700 RValue RHS = RValue::get(EmitScalarExpr(Init));
701 EmitStoreThroughLValue(RHS, LHS);
702 }
703 break;
704 case TEK_Complex:
705 EmitComplexExprIntoLValue(Init, LHS, /*isInit*/ true);
706 break;
707 case TEK_Aggregate: {
708 AggValueSlot Slot = AggValueSlot::forLValue(
709 LHS, *this, AggValueSlot::IsDestructed,
710 AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased,
711 getOverlapForFieldInit(Field), AggValueSlot::IsNotZeroed,
712 // Checks are made by the code that calls constructor.
713 AggValueSlot::IsSanitizerChecked);
714 EmitAggExpr(Init, Slot);
715 break;
716 }
717 }
718
719 // Ensure that we destroy this object if an exception is thrown
720 // later in the constructor.
721 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
722 if (needsEHCleanup(dtorKind))
723 pushEHDestroy(dtorKind, LHS.getAddress(*this), FieldType);
724}
725
726/// Checks whether the given constructor is a valid subject for the
727/// complete-to-base constructor delegation optimization, i.e.
728/// emitting the complete constructor as a simple call to the base
729/// constructor.
730bool CodeGenFunction::IsConstructorDelegationValid(
731 const CXXConstructorDecl *Ctor) {
732
733 // Currently we disable the optimization for classes with virtual
734 // bases because (1) the addresses of parameter variables need to be
735 // consistent across all initializers but (2) the delegate function
736 // call necessarily creates a second copy of the parameter variable.
737 //
738 // The limiting example (purely theoretical AFAIK):
739 // struct A { A(int &c) { c++; } };
740 // struct B : virtual A {
741 // B(int count) : A(count) { printf("%d\n", count); }
742 // };
743 // ...although even this example could in principle be emitted as a
744 // delegation since the address of the parameter doesn't escape.
745 if (Ctor->getParent()->getNumVBases()) {
746 // TODO: white-list trivial vbase initializers. This case wouldn't
747 // be subject to the restrictions below.
748
749 // TODO: white-list cases where:
750 // - there are no non-reference parameters to the constructor
751 // - the initializers don't access any non-reference parameters
752 // - the initializers don't take the address of non-reference
753 // parameters
754 // - etc.
755 // If we ever add any of the above cases, remember that:
756 // - function-try-blocks will always exclude this optimization
757 // - we need to perform the constructor prologue and cleanup in
758 // EmitConstructorBody.
759
760 return false;
761 }
762
763 // We also disable the optimization for variadic functions because
764 // it's impossible to "re-pass" varargs.
765 if (Ctor->getType()->castAs<FunctionProtoType>()->isVariadic())
766 return false;
767
768 // FIXME: Decide if we can do a delegation of a delegating constructor.
769 if (Ctor->isDelegatingConstructor())
770 return false;
771
772 return true;
773}
774
775// Emit code in ctor (Prologue==true) or dtor (Prologue==false)
776// to poison the extra field paddings inserted under
777// -fsanitize-address-field-padding=1|2.
778void CodeGenFunction::EmitAsanPrologueOrEpilogue(bool Prologue) {
779 ASTContext &Context = getContext();
780 const CXXRecordDecl *ClassDecl =
781 Prologue ? cast<CXXConstructorDecl>(CurGD.getDecl())->getParent()
782 : cast<CXXDestructorDecl>(CurGD.getDecl())->getParent();
783 if (!ClassDecl->mayInsertExtraPadding()) return;
784
785 struct SizeAndOffset {
786 uint64_t Size;
787 uint64_t Offset;
788 };
789
790 unsigned PtrSize = CGM.getDataLayout().getPointerSizeInBits();
791 const ASTRecordLayout &Info = Context.getASTRecordLayout(ClassDecl);
792
793 // Populate sizes and offsets of fields.
794 SmallVector<SizeAndOffset, 16> SSV(Info.getFieldCount());
795 for (unsigned i = 0, e = Info.getFieldCount(); i != e; ++i)
796 SSV[i].Offset =
797 Context.toCharUnitsFromBits(Info.getFieldOffset(i)).getQuantity();
798
799 size_t NumFields = 0;
800 for (const auto *Field : ClassDecl->fields()) {
801 const FieldDecl *D = Field;
802 auto FieldInfo = Context.getTypeInfoInChars(D->getType());
803 CharUnits FieldSize = FieldInfo.Width;
804 assert(NumFields < SSV.size());
805 SSV[NumFields].Size = D->isBitField() ? 0 : FieldSize.getQuantity();
806 NumFields++;
807 }
808 assert(NumFields == SSV.size());
809 if (SSV.size() <= 1) return;
810
811 // We will insert calls to __asan_* run-time functions.
812 // LLVM AddressSanitizer pass may decide to inline them later.
813 llvm::Type *Args[2] = {IntPtrTy, IntPtrTy};
814 llvm::FunctionType *FTy =
815 llvm::FunctionType::get(CGM.VoidTy, Args, false);
816 llvm::FunctionCallee F = CGM.CreateRuntimeFunction(
817 FTy, Prologue ? "__asan_poison_intra_object_redzone"
818 : "__asan_unpoison_intra_object_redzone");
819
820 llvm::Value *ThisPtr = LoadCXXThis();
821 ThisPtr = Builder.CreatePtrToInt(ThisPtr, IntPtrTy);
822 uint64_t TypeSize = Info.getNonVirtualSize().getQuantity();
823 // For each field check if it has sufficient padding,
824 // if so (un)poison it with a call.
825 for (size_t i = 0; i < SSV.size(); i++) {
826 uint64_t AsanAlignment = 8;
827 uint64_t NextField = i == SSV.size() - 1 ? TypeSize : SSV[i + 1].Offset;
828 uint64_t PoisonSize = NextField - SSV[i].Offset - SSV[i].Size;
829 uint64_t EndOffset = SSV[i].Offset + SSV[i].Size;
830 if (PoisonSize < AsanAlignment || !SSV[i].Size ||
831 (NextField % AsanAlignment) != 0)
832 continue;
833 Builder.CreateCall(
834 F, {Builder.CreateAdd(ThisPtr, Builder.getIntN(PtrSize, EndOffset)),
835 Builder.getIntN(PtrSize, PoisonSize)});
836 }
837}
838
839/// EmitConstructorBody - Emits the body of the current constructor.
840void CodeGenFunction::EmitConstructorBody(FunctionArgList &Args) {
841 EmitAsanPrologueOrEpilogue(true);
842 const CXXConstructorDecl *Ctor = cast<CXXConstructorDecl>(CurGD.getDecl());
843 CXXCtorType CtorType = CurGD.getCtorType();
844
845 assert((CGM.getTarget().getCXXABI().hasConstructorVariants() ||
846 CtorType == Ctor_Complete) &&
847 "can only generate complete ctor for this ABI");
848
849 // Before we go any further, try the complete->base constructor
850 // delegation optimization.
851 if (CtorType == Ctor_Complete && IsConstructorDelegationValid(Ctor) &&
852 CGM.getTarget().getCXXABI().hasConstructorVariants()) {
853 EmitDelegateCXXConstructorCall(Ctor, Ctor_Base, Args, Ctor->getEndLoc());
854 return;
855 }
856
857 const FunctionDecl *Definition = nullptr;
858 Stmt *Body = Ctor->getBody(Definition);
859 assert(Definition == Ctor && "emitting wrong constructor body");
860
861 // Enter the function-try-block before the constructor prologue if
862 // applicable.
863 bool IsTryBody = (Body && isa<CXXTryStmt>(Body));
864 if (IsTryBody)
865 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
866
867 incrementProfileCounter(Body);
868
869 RunCleanupsScope RunCleanups(*this);
870
871 // TODO: in restricted cases, we can emit the vbase initializers of
872 // a complete ctor and then delegate to the base ctor.
873
874 // Emit the constructor prologue, i.e. the base and member
875 // initializers.
876 EmitCtorPrologue(Ctor, CtorType, Args);
877
878 // Emit the body of the statement.
879 if (IsTryBody)
880 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
881 else if (Body)
882 EmitStmt(Body);
883
884 // Emit any cleanup blocks associated with the member or base
885 // initializers, which includes (along the exceptional path) the
886 // destructors for those members and bases that were fully
887 // constructed.
888 RunCleanups.ForceCleanup();
889
890 if (IsTryBody)
891 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
892}
893
894namespace {
895 /// RAII object to indicate that codegen is copying the value representation
896 /// instead of the object representation. Useful when copying a struct or
897 /// class which has uninitialized members and we're only performing
898 /// lvalue-to-rvalue conversion on the object but not its members.
899 class CopyingValueRepresentation {
900 public:
901 explicit CopyingValueRepresentation(CodeGenFunction &CGF)
902 : CGF(CGF), OldSanOpts(CGF.SanOpts) {
903 CGF.SanOpts.set(SanitizerKind::Bool, false);
904 CGF.SanOpts.set(SanitizerKind::Enum, false);
905 }
906 ~CopyingValueRepresentation() {
907 CGF.SanOpts = OldSanOpts;
908 }
909 private:
910 CodeGenFunction &CGF;
911 SanitizerSet OldSanOpts;
912 };
913} // end anonymous namespace
914
915namespace {
916 class FieldMemcpyizer {
917 public:
918 FieldMemcpyizer(CodeGenFunction &CGF, const CXXRecordDecl *ClassDecl,
919 const VarDecl *SrcRec)
920 : CGF(CGF), ClassDecl(ClassDecl), SrcRec(SrcRec),
921 RecLayout(CGF.getContext().getASTRecordLayout(ClassDecl)),
922 FirstField(nullptr), LastField(nullptr), FirstFieldOffset(0),
923 LastFieldOffset(0), LastAddedFieldIndex(0) {}
924
925 bool isMemcpyableField(FieldDecl *F) const {
926 // Never memcpy fields when we are adding poisoned paddings.
927 if (CGF.getContext().getLangOpts().SanitizeAddressFieldPadding)
928 return false;
929 Qualifiers Qual = F->getType().getQualifiers();
930 if (Qual.hasVolatile() || Qual.hasObjCLifetime())
931 return false;
932 return true;
933 }
934
935 void addMemcpyableField(FieldDecl *F) {
936 if (F->isZeroSize(CGF.getContext()))
937 return;
938 if (!FirstField)
939 addInitialField(F);
940 else
941 addNextField(F);
942 }
943
944 CharUnits getMemcpySize(uint64_t FirstByteOffset) const {
945 ASTContext &Ctx = CGF.getContext();
946 unsigned LastFieldSize =
947 LastField->isBitField()
948 ? LastField->getBitWidthValue(Ctx)
949 : Ctx.toBits(
950 Ctx.getTypeInfoDataSizeInChars(LastField->getType()).Width);
951 uint64_t MemcpySizeBits = LastFieldOffset + LastFieldSize -
952 FirstByteOffset + Ctx.getCharWidth() - 1;
953 CharUnits MemcpySize = Ctx.toCharUnitsFromBits(MemcpySizeBits);
954 return MemcpySize;
955 }
956
957 void emitMemcpy() {
958 // Give the subclass a chance to bail out if it feels the memcpy isn't
959 // worth it (e.g. Hasn't aggregated enough data).
960 if (!FirstField) {
961 return;
962 }
963
964 uint64_t FirstByteOffset;
965 if (FirstField->isBitField()) {
966 const CGRecordLayout &RL =
967 CGF.getTypes().getCGRecordLayout(FirstField->getParent());
968 const CGBitFieldInfo &BFInfo = RL.getBitFieldInfo(FirstField);
969 // FirstFieldOffset is not appropriate for bitfields,
970 // we need to use the storage offset instead.
971 FirstByteOffset = CGF.getContext().toBits(BFInfo.StorageOffset);
972 } else {
973 FirstByteOffset = FirstFieldOffset;
974 }
975
976 CharUnits MemcpySize = getMemcpySize(FirstByteOffset);
977 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
978 Address ThisPtr = CGF.LoadCXXThisAddress();
979 LValue DestLV = CGF.MakeAddrLValue(ThisPtr, RecordTy);
980 LValue Dest = CGF.EmitLValueForFieldInitialization(DestLV, FirstField);
981 llvm::Value *SrcPtr = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(SrcRec));
982 LValue SrcLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy);
983 LValue Src = CGF.EmitLValueForFieldInitialization(SrcLV, FirstField);
984
985 emitMemcpyIR(
986 Dest.isBitField() ? Dest.getBitFieldAddress() : Dest.getAddress(CGF),
987 Src.isBitField() ? Src.getBitFieldAddress() : Src.getAddress(CGF),
988 MemcpySize);
989 reset();
990 }
991
992 void reset() {
993 FirstField = nullptr;
994 }
995
996 protected:
997 CodeGenFunction &CGF;
998 const CXXRecordDecl *ClassDecl;
999
1000 private:
1001 void emitMemcpyIR(Address DestPtr, Address SrcPtr, CharUnits Size) {
1002 llvm::PointerType *DPT = DestPtr.getType();
1003 llvm::Type *DBP =
1004 llvm::Type::getInt8PtrTy(CGF.getLLVMContext(), DPT->getAddressSpace());
1005 DestPtr = CGF.Builder.CreateBitCast(DestPtr, DBP);
1006
1007 llvm::PointerType *SPT = SrcPtr.getType();
1008 llvm::Type *SBP =
1009 llvm::Type::getInt8PtrTy(CGF.getLLVMContext(), SPT->getAddressSpace());
1010 SrcPtr = CGF.Builder.CreateBitCast(SrcPtr, SBP);
1011
1012 CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, Size.getQuantity());
1013 }
1014
1015 void addInitialField(FieldDecl *F) {
1016 FirstField = F;
1017 LastField = F;
1018 FirstFieldOffset = RecLayout.getFieldOffset(F->getFieldIndex());
1019 LastFieldOffset = FirstFieldOffset;
1020 LastAddedFieldIndex = F->getFieldIndex();
1021 }
1022
1023 void addNextField(FieldDecl *F) {
1024 // For the most part, the following invariant will hold:
1025 // F->getFieldIndex() == LastAddedFieldIndex + 1
1026 // The one exception is that Sema won't add a copy-initializer for an
1027 // unnamed bitfield, which will show up here as a gap in the sequence.
1028 assert(F->getFieldIndex() >= LastAddedFieldIndex + 1 &&
1029 "Cannot aggregate fields out of order.");
1030 LastAddedFieldIndex = F->getFieldIndex();
1031
1032 // The 'first' and 'last' fields are chosen by offset, rather than field
1033 // index. This allows the code to support bitfields, as well as regular
1034 // fields.
1035 uint64_t FOffset = RecLayout.getFieldOffset(F->getFieldIndex());
1036 if (FOffset < FirstFieldOffset) {
1037 FirstField = F;
1038 FirstFieldOffset = FOffset;
1039 } else if (FOffset >= LastFieldOffset) {
1040 LastField = F;
1041 LastFieldOffset = FOffset;
1042 }
1043 }
1044
1045 const VarDecl *SrcRec;
1046 const ASTRecordLayout &RecLayout;
1047 FieldDecl *FirstField;
1048 FieldDecl *LastField;
1049 uint64_t FirstFieldOffset, LastFieldOffset;
1050 unsigned LastAddedFieldIndex;
1051 };
1052
1053 class ConstructorMemcpyizer : public FieldMemcpyizer {
1054 private:
1055 /// Get source argument for copy constructor. Returns null if not a copy
1056 /// constructor.
1057 static const VarDecl *getTrivialCopySource(CodeGenFunction &CGF,
1058 const CXXConstructorDecl *CD,
1059 FunctionArgList &Args) {
1060 if (CD->isCopyOrMoveConstructor() && CD->isDefaulted())
1061 return Args[CGF.CGM.getCXXABI().getSrcArgforCopyCtor(CD, Args)];
1062 return nullptr;
1063 }
1064
1065 // Returns true if a CXXCtorInitializer represents a member initialization
1066 // that can be rolled into a memcpy.
1067 bool isMemberInitMemcpyable(CXXCtorInitializer *MemberInit) const {
1068 if (!MemcpyableCtor)
1069 return false;
1070 FieldDecl *Field = MemberInit->getMember();
1071 assert(Field && "No field for member init.");
1072 QualType FieldType = Field->getType();
1073 CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit());
1074
1075 // Bail out on non-memcpyable, not-trivially-copyable members.
1076 if (!(CE && isMemcpyEquivalentSpecialMember(CE->getConstructor())) &&
1077 !(FieldType.isTriviallyCopyableType(CGF.getContext()) ||
1078 FieldType->isReferenceType()))
1079 return false;
1080
1081 // Bail out on volatile fields.
1082 if (!isMemcpyableField(Field))
1083 return false;
1084
1085 // Otherwise we're good.
1086 return true;
1087 }
1088
1089 public:
1090 ConstructorMemcpyizer(CodeGenFunction &CGF, const CXXConstructorDecl *CD,
1091 FunctionArgList &Args)
1092 : FieldMemcpyizer(CGF, CD->getParent(), getTrivialCopySource(CGF, CD, Args)),
1093 ConstructorDecl(CD),
1094 MemcpyableCtor(CD->isDefaulted() &&
1095 CD->isCopyOrMoveConstructor() &&
1096 CGF.getLangOpts().getGC() == LangOptions::NonGC),
1097 Args(Args) { }
1098
1099 void addMemberInitializer(CXXCtorInitializer *MemberInit) {
1100 if (isMemberInitMemcpyable(MemberInit)) {
1101 AggregatedInits.push_back(MemberInit);
1102 addMemcpyableField(MemberInit->getMember());
1103 } else {
1104 emitAggregatedInits();
1105 EmitMemberInitializer(CGF, ConstructorDecl->getParent(), MemberInit,
1106 ConstructorDecl, Args);
1107 }
1108 }
1109
1110 void emitAggregatedInits() {
1111 if (AggregatedInits.size() <= 1) {
1112 // This memcpy is too small to be worthwhile. Fall back on default
1113 // codegen.
1114 if (!AggregatedInits.empty()) {
1115 CopyingValueRepresentation CVR(CGF);
1116 EmitMemberInitializer(CGF, ConstructorDecl->getParent(),
1117 AggregatedInits[0], ConstructorDecl, Args);
1118 AggregatedInits.clear();
1119 }
1120 reset();
1121 return;
1122 }
1123
1124 pushEHDestructors();
1125 emitMemcpy();
1126 AggregatedInits.clear();
1127 }
1128
1129 void pushEHDestructors() {
1130 Address ThisPtr = CGF.LoadCXXThisAddress();
1131 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
1132 LValue LHS = CGF.MakeAddrLValue(ThisPtr, RecordTy);
1133
1134 for (unsigned i = 0; i < AggregatedInits.size(); ++i) {
1135 CXXCtorInitializer *MemberInit = AggregatedInits[i];
1136 QualType FieldType = MemberInit->getAnyMember()->getType();
1137 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
1138 if (!CGF.needsEHCleanup(dtorKind))
1139 continue;
1140 LValue FieldLHS = LHS;
1141 EmitLValueForAnyFieldInitialization(CGF, MemberInit, FieldLHS);
1142 CGF.pushEHDestroy(dtorKind, FieldLHS.getAddress(CGF), FieldType);
1143 }
1144 }
1145
1146 void finish() {
1147 emitAggregatedInits();
1148 }
1149
1150 private:
1151 const CXXConstructorDecl *ConstructorDecl;
1152 bool MemcpyableCtor;
1153 FunctionArgList &Args;
1154 SmallVector<CXXCtorInitializer*, 16> AggregatedInits;
1155 };
1156
1157 class AssignmentMemcpyizer : public FieldMemcpyizer {
1158 private:
1159 // Returns the memcpyable field copied by the given statement, if one
1160 // exists. Otherwise returns null.
1161 FieldDecl *getMemcpyableField(Stmt *S) {
1162 if (!AssignmentsMemcpyable)
1163 return nullptr;
1164 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(S)) {
1165 // Recognise trivial assignments.
1166 if (BO->getOpcode() != BO_Assign)
1167 return nullptr;
1168 MemberExpr *ME = dyn_cast<MemberExpr>(BO->getLHS());
1169 if (!ME)
1170 return nullptr;
1171 FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl());
1172 if (!Field || !isMemcpyableField(Field))
1173 return nullptr;
1174 Stmt *RHS = BO->getRHS();
1175 if (ImplicitCastExpr *EC = dyn_cast<ImplicitCastExpr>(RHS))
1176 RHS = EC->getSubExpr();
1177 if (!RHS)
1178 return nullptr;
1179 if (MemberExpr *ME2 = dyn_cast<MemberExpr>(RHS)) {
1180 if (ME2->getMemberDecl() == Field)
1181 return Field;
1182 }
1183 return nullptr;
1184 } else if (CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(S)) {
1185 CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MCE->getCalleeDecl());
1186 if (!(MD && isMemcpyEquivalentSpecialMember(MD)))
1187 return nullptr;
1188 MemberExpr *IOA = dyn_cast<MemberExpr>(MCE->getImplicitObjectArgument());
1189 if (!IOA)
1190 return nullptr;
1191 FieldDecl *Field = dyn_cast<FieldDecl>(IOA->getMemberDecl());
1192 if (!Field || !isMemcpyableField(Field))
1193 return nullptr;
1194 MemberExpr *Arg0 = dyn_cast<MemberExpr>(MCE->getArg(0));
1195 if (!Arg0 || Field != dyn_cast<FieldDecl>(Arg0->getMemberDecl()))
1196 return nullptr;
1197 return Field;
1198 } else if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
1199 FunctionDecl *FD = dyn_cast<FunctionDecl>(CE->getCalleeDecl());
1200 if (!FD || FD->getBuiltinID() != Builtin::BI__builtin_memcpy)
1201 return nullptr;
1202 Expr *DstPtr = CE->getArg(0);
1203 if (ImplicitCastExpr *DC = dyn_cast<ImplicitCastExpr>(DstPtr))
1204 DstPtr = DC->getSubExpr();
1205 UnaryOperator *DUO = dyn_cast<UnaryOperator>(DstPtr);
1206 if (!DUO || DUO->getOpcode() != UO_AddrOf)
1207 return nullptr;
1208 MemberExpr *ME = dyn_cast<MemberExpr>(DUO->getSubExpr());
1209 if (!ME)
1210 return nullptr;
1211 FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl());
1212 if (!Field || !isMemcpyableField(Field))
1213 return nullptr;
1214 Expr *SrcPtr = CE->getArg(1);
1215 if (ImplicitCastExpr *SC = dyn_cast<ImplicitCastExpr>(SrcPtr))
1216 SrcPtr = SC->getSubExpr();
1217 UnaryOperator *SUO = dyn_cast<UnaryOperator>(SrcPtr);
1218 if (!SUO || SUO->getOpcode() != UO_AddrOf)
1219 return nullptr;
1220 MemberExpr *ME2 = dyn_cast<MemberExpr>(SUO->getSubExpr());
1221 if (!ME2 || Field != dyn_cast<FieldDecl>(ME2->getMemberDecl()))
1222 return nullptr;
1223 return Field;
1224 }
1225
1226 return nullptr;
1227 }
1228
1229 bool AssignmentsMemcpyable;
1230 SmallVector<Stmt*, 16> AggregatedStmts;
1231
1232 public:
1233 AssignmentMemcpyizer(CodeGenFunction &CGF, const CXXMethodDecl *AD,
1234 FunctionArgList &Args)
1235 : FieldMemcpyizer(CGF, AD->getParent(), Args[Args.size() - 1]),
1236 AssignmentsMemcpyable(CGF.getLangOpts().getGC() == LangOptions::NonGC) {
1237 assert(Args.size() == 2);
1238 }
1239
1240 void emitAssignment(Stmt *S) {
1241 FieldDecl *F = getMemcpyableField(S);
1242 if (F) {
1243 addMemcpyableField(F);
1244 AggregatedStmts.push_back(S);
1245 } else {
1246 emitAggregatedStmts();
1247 CGF.EmitStmt(S);
1248 }
1249 }
1250
1251 void emitAggregatedStmts() {
1252 if (AggregatedStmts.size() <= 1) {
1253 if (!AggregatedStmts.empty()) {
1254 CopyingValueRepresentation CVR(CGF);
1255 CGF.EmitStmt(AggregatedStmts[0]);
1256 }
1257 reset();
1258 }
1259
1260 emitMemcpy();
1261 AggregatedStmts.clear();
1262 }
1263
1264 void finish() {
1265 emitAggregatedStmts();
1266 }
1267 };
1268} // end anonymous namespace
1269
1270static bool isInitializerOfDynamicClass(const CXXCtorInitializer *BaseInit) {
1271 const Type *BaseType = BaseInit->getBaseClass();
1272 const auto *BaseClassDecl =
1273 cast<CXXRecordDecl>(BaseType->castAs<RecordType>()->getDecl());
1274 return BaseClassDecl->isDynamicClass();
1275}
1276
1277/// EmitCtorPrologue - This routine generates necessary code to initialize
1278/// base classes and non-static data members belonging to this constructor.
1279void CodeGenFunction::EmitCtorPrologue(const CXXConstructorDecl *CD,
1280 CXXCtorType CtorType,
1281 FunctionArgList &Args) {
1282 if (CD->isDelegatingConstructor())
1283 return EmitDelegatingCXXConstructorCall(CD, Args);
1284
1285 const CXXRecordDecl *ClassDecl = CD->getParent();
1286
1287 CXXConstructorDecl::init_const_iterator B = CD->init_begin(),
1288 E = CD->init_end();
1289
1290 // Virtual base initializers first, if any. They aren't needed if:
1291 // - This is a base ctor variant
1292 // - There are no vbases
1293 // - The class is abstract, so a complete object of it cannot be constructed
1294 //
1295 // The check for an abstract class is necessary because sema may not have
1296 // marked virtual base destructors referenced.
1297 bool ConstructVBases = CtorType != Ctor_Base &&
1298 ClassDecl->getNumVBases() != 0 &&
1299 !ClassDecl->isAbstract();
1300
1301 // In the Microsoft C++ ABI, there are no constructor variants. Instead, the
1302 // constructor of a class with virtual bases takes an additional parameter to
1303 // conditionally construct the virtual bases. Emit that check here.
1304 llvm::BasicBlock *BaseCtorContinueBB = nullptr;
1305 if (ConstructVBases &&
1306 !CGM.getTarget().getCXXABI().hasConstructorVariants()) {
1307 BaseCtorContinueBB =
1308 CGM.getCXXABI().EmitCtorCompleteObjectHandler(*this, ClassDecl);
1309 assert(BaseCtorContinueBB);
1310 }
1311
1312 llvm::Value *const OldThis = CXXThisValue;
1313 for (; B != E && (*B)->isBaseInitializer() && (*B)->isBaseVirtual(); B++) {
1314 if (!ConstructVBases)
1315 continue;
1316 if (CGM.getCodeGenOpts().StrictVTablePointers &&
1317 CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1318 isInitializerOfDynamicClass(*B))
1319 CXXThisValue = Builder.CreateLaunderInvariantGroup(LoadCXXThis());
1320 EmitBaseInitializer(*this, ClassDecl, *B);
1321 }
1322
1323 if (BaseCtorContinueBB) {
1324 // Complete object handler should continue to the remaining initializers.
1325 Builder.CreateBr(BaseCtorContinueBB);
1326 EmitBlock(BaseCtorContinueBB);
1327 }
1328
1329 // Then, non-virtual base initializers.
1330 for (; B != E && (*B)->isBaseInitializer(); B++) {
1331 assert(!(*B)->isBaseVirtual());
1332
1333 if (CGM.getCodeGenOpts().StrictVTablePointers &&
1334 CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1335 isInitializerOfDynamicClass(*B))
1336 CXXThisValue = Builder.CreateLaunderInvariantGroup(LoadCXXThis());
1337 EmitBaseInitializer(*this, ClassDecl, *B);
1338 }
1339
1340 CXXThisValue = OldThis;
1341
1342 InitializeVTablePointers(ClassDecl);
1343
1344 // And finally, initialize class members.
1345 FieldConstructionScope FCS(*this, LoadCXXThisAddress());
1346 ConstructorMemcpyizer CM(*this, CD, Args);
1347 for (; B != E; B++) {
1348 CXXCtorInitializer *Member = (*B);
1349 assert(!Member->isBaseInitializer());
1350 assert(Member->isAnyMemberInitializer() &&
1351 "Delegating initializer on non-delegating constructor");
1352 CM.addMemberInitializer(Member);
1353 }
1354 CM.finish();
1355}
1356
1357static bool
1358FieldHasTrivialDestructorBody(ASTContext &Context, const FieldDecl *Field);
1359
1360static bool
1361HasTrivialDestructorBody(ASTContext &Context,
1362 const CXXRecordDecl *BaseClassDecl,
1363 const CXXRecordDecl *MostDerivedClassDecl)
1364{
1365 // If the destructor is trivial we don't have to check anything else.
1366 if (BaseClassDecl->hasTrivialDestructor())
1367 return true;
1368
1369 if (!BaseClassDecl->getDestructor()->hasTrivialBody())
1370 return false;
1371
1372 // Check fields.
1373 for (const auto *Field : BaseClassDecl->fields())
1374 if (!FieldHasTrivialDestructorBody(Context, Field))
1375 return false;
1376
1377 // Check non-virtual bases.
1378 for (const auto &I : BaseClassDecl->bases()) {
1379 if (I.isVirtual())
1380 continue;
1381
1382 const CXXRecordDecl *NonVirtualBase =
1383 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
1384 if (!HasTrivialDestructorBody(Context, NonVirtualBase,
1385 MostDerivedClassDecl))
1386 return false;
1387 }
1388
1389 if (BaseClassDecl == MostDerivedClassDecl) {
1390 // Check virtual bases.
1391 for (const auto &I : BaseClassDecl->vbases()) {
1392 const CXXRecordDecl *VirtualBase =
1393 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
1394 if (!HasTrivialDestructorBody(Context, VirtualBase,
1395 MostDerivedClassDecl))
1396 return false;
1397 }
1398 }
1399
1400 return true;
1401}
1402
1403static bool
1404FieldHasTrivialDestructorBody(ASTContext &Context,
1405 const FieldDecl *Field)
1406{
1407 QualType FieldBaseElementType = Context.getBaseElementType(Field->getType());
1408
1409 const RecordType *RT = FieldBaseElementType->getAs<RecordType>();
1410 if (!RT)
1411 return true;
1412
1413 CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
1414
1415 // The destructor for an implicit anonymous union member is never invoked.
1416 if (FieldClassDecl->isUnion() && FieldClassDecl->isAnonymousStructOrUnion())
1417 return false;
1418
1419 return HasTrivialDestructorBody(Context, FieldClassDecl, FieldClassDecl);
1420}
1421
1422/// CanSkipVTablePointerInitialization - Check whether we need to initialize
1423/// any vtable pointers before calling this destructor.
1424static bool CanSkipVTablePointerInitialization(CodeGenFunction &CGF,
1425 const CXXDestructorDecl *Dtor) {
1426 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1427 if (!ClassDecl->isDynamicClass())
1428 return true;
1429
1430 if (!Dtor->hasTrivialBody())
1431 return false;
1432
1433 // Check the fields.
1434 for (const auto *Field : ClassDecl->fields())
1435 if (!FieldHasTrivialDestructorBody(CGF.getContext(), Field))
1436 return false;
1437
1438 return true;
1439}
1440
1441/// EmitDestructorBody - Emits the body of the current destructor.
1442void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) {
1443 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CurGD.getDecl());
1444 CXXDtorType DtorType = CurGD.getDtorType();
1445
1446 // For an abstract class, non-base destructors are never used (and can't
1447 // be emitted in general, because vbase dtors may not have been validated
1448 // by Sema), but the Itanium ABI doesn't make them optional and Clang may
1449 // in fact emit references to them from other compilations, so emit them
1450 // as functions containing a trap instruction.
1451 if (DtorType != Dtor_Base && Dtor->getParent()->isAbstract()) {
1452 llvm::CallInst *TrapCall = EmitTrapCall(llvm::Intrinsic::trap);
1453 TrapCall->setDoesNotReturn();
1454 TrapCall->setDoesNotThrow();
1455 Builder.CreateUnreachable();
1456 Builder.ClearInsertionPoint();
1457 return;
1458 }
1459
1460 Stmt *Body = Dtor->getBody();
1461 if (Body)
1462 incrementProfileCounter(Body);
1463
1464 // The call to operator delete in a deleting destructor happens
1465 // outside of the function-try-block, which means it's always
1466 // possible to delegate the destructor body to the complete
1467 // destructor. Do so.
1468 if (DtorType == Dtor_Deleting) {
1469 RunCleanupsScope DtorEpilogue(*this);
1470 EnterDtorCleanups(Dtor, Dtor_Deleting);
1471 if (HaveInsertPoint()) {
1472 QualType ThisTy = Dtor->getThisObjectType();
1473 EmitCXXDestructorCall(Dtor, Dtor_Complete, /*ForVirtualBase=*/false,
1474 /*Delegating=*/false, LoadCXXThisAddress(), ThisTy);
1475 }
1476 return;
1477 }
1478
1479 // If the body is a function-try-block, enter the try before
1480 // anything else.
1481 bool isTryBody = (Body && isa<CXXTryStmt>(Body));
1482 if (isTryBody)
1483 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
1484 EmitAsanPrologueOrEpilogue(false);
1485
1486 // Enter the epilogue cleanups.
1487 RunCleanupsScope DtorEpilogue(*this);
1488
1489 // If this is the complete variant, just invoke the base variant;
1490 // the epilogue will destruct the virtual bases. But we can't do
1491 // this optimization if the body is a function-try-block, because
1492 // we'd introduce *two* handler blocks. In the Microsoft ABI, we
1493 // always delegate because we might not have a definition in this TU.
1494 switch (DtorType) {
1495 case Dtor_Comdat: llvm_unreachable("not expecting a COMDAT");
1496 case Dtor_Deleting: llvm_unreachable("already handled deleting case");
1497
1498 case Dtor_Complete:
1499 assert((Body || getTarget().getCXXABI().isMicrosoft()) &&
1500 "can't emit a dtor without a body for non-Microsoft ABIs");
1501
1502 // Enter the cleanup scopes for virtual bases.
1503 EnterDtorCleanups(Dtor, Dtor_Complete);
1504
1505 if (!isTryBody) {
1506 QualType ThisTy = Dtor->getThisObjectType();
1507 EmitCXXDestructorCall(Dtor, Dtor_Base, /*ForVirtualBase=*/false,
1508 /*Delegating=*/false, LoadCXXThisAddress(), ThisTy);
1509 break;
1510 }
1511
1512 // Fallthrough: act like we're in the base variant.
1513 LLVM_FALLTHROUGH;
1514
1515 case Dtor_Base:
1516 assert(Body);
1517
1518 // Enter the cleanup scopes for fields and non-virtual bases.
1519 EnterDtorCleanups(Dtor, Dtor_Base);
1520
1521 // Initialize the vtable pointers before entering the body.
1522 if (!CanSkipVTablePointerInitialization(*this, Dtor)) {
1523 // Insert the llvm.launder.invariant.group intrinsic before initializing
1524 // the vptrs to cancel any previous assumptions we might have made.
1525 if (CGM.getCodeGenOpts().StrictVTablePointers &&
1526 CGM.getCodeGenOpts().OptimizationLevel > 0)
1527 CXXThisValue = Builder.CreateLaunderInvariantGroup(LoadCXXThis());
1528 InitializeVTablePointers(Dtor->getParent());
1529 }
1530
1531 if (isTryBody)
1532 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
1533 else if (Body)
1534 EmitStmt(Body);
1535 else {
1536 assert(Dtor->isImplicit() && "bodyless dtor not implicit");
1537 // nothing to do besides what's in the epilogue
1538 }
1539 // -fapple-kext must inline any call to this dtor into
1540 // the caller's body.
1541 if (getLangOpts().AppleKext)
1542 CurFn->addFnAttr(llvm::Attribute::AlwaysInline);
1543
1544 break;
1545 }
1546
1547 // Jump out through the epilogue cleanups.
1548 DtorEpilogue.ForceCleanup();
1549
1550 // Exit the try if applicable.
1551 if (isTryBody)
1552 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
1553}
1554
1555void CodeGenFunction::emitImplicitAssignmentOperatorBody(FunctionArgList &Args) {
1556 const CXXMethodDecl *AssignOp = cast<CXXMethodDecl>(CurGD.getDecl());
1557 const Stmt *RootS = AssignOp->getBody();
1558 assert(isa<CompoundStmt>(RootS) &&
1559 "Body of an implicit assignment operator should be compound stmt.");
1560 const CompoundStmt *RootCS = cast<CompoundStmt>(RootS);
1561
1562 LexicalScope Scope(*this, RootCS->getSourceRange());
1563
1564 incrementProfileCounter(RootCS);
1565 AssignmentMemcpyizer AM(*this, AssignOp, Args);
1566 for (auto *I : RootCS->body())
1567 AM.emitAssignment(I);
1568 AM.finish();
1569}
1570
1571namespace {
1572 llvm::Value *LoadThisForDtorDelete(CodeGenFunction &CGF,
1573 const CXXDestructorDecl *DD) {
1574 if (Expr *ThisArg = DD->getOperatorDeleteThisArg())
1575 return CGF.EmitScalarExpr(ThisArg);
1576 return CGF.LoadCXXThis();
1577 }
1578
1579 /// Call the operator delete associated with the current destructor.
1580 struct CallDtorDelete final : EHScopeStack::Cleanup {
1581 CallDtorDelete() {}
1582
1583 void Emit(CodeGenFunction &CGF, Flags flags) override {
1584 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
1585 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1586 CGF.EmitDeleteCall(Dtor->getOperatorDelete(),
1587 LoadThisForDtorDelete(CGF, Dtor),
1588 CGF.getContext().getTagDeclType(ClassDecl));
1589 }
1590 };
1591
1592 void EmitConditionalDtorDeleteCall(CodeGenFunction &CGF,
1593 llvm::Value *ShouldDeleteCondition,
1594 bool ReturnAfterDelete) {
1595 llvm::BasicBlock *callDeleteBB = CGF.createBasicBlock("dtor.call_delete");
1596 llvm::BasicBlock *continueBB = CGF.createBasicBlock("dtor.continue");
1597 llvm::Value *ShouldCallDelete
1598 = CGF.Builder.CreateIsNull(ShouldDeleteCondition);
1599 CGF.Builder.CreateCondBr(ShouldCallDelete, continueBB, callDeleteBB);
1600
1601 CGF.EmitBlock(callDeleteBB);
1602 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
1603 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1604 CGF.EmitDeleteCall(Dtor->getOperatorDelete(),
1605 LoadThisForDtorDelete(CGF, Dtor),
1606 CGF.getContext().getTagDeclType(ClassDecl));
1607 assert(Dtor->getOperatorDelete()->isDestroyingOperatorDelete() ==
1608 ReturnAfterDelete &&
1609 "unexpected value for ReturnAfterDelete");
1610 if (ReturnAfterDelete)
1611 CGF.EmitBranchThroughCleanup(CGF.ReturnBlock);
1612 else
1613 CGF.Builder.CreateBr(continueBB);
1614
1615 CGF.EmitBlock(continueBB);
1616 }
1617
1618 struct CallDtorDeleteConditional final : EHScopeStack::Cleanup {
1619 llvm::Value *ShouldDeleteCondition;
1620
1621 public:
1622 CallDtorDeleteConditional(llvm::Value *ShouldDeleteCondition)
1623 : ShouldDeleteCondition(ShouldDeleteCondition) {
1624 assert(ShouldDeleteCondition != nullptr);
1625 }
1626
1627 void Emit(CodeGenFunction &CGF, Flags flags) override {
1628 EmitConditionalDtorDeleteCall(CGF, ShouldDeleteCondition,
1629 /*ReturnAfterDelete*/false);
1630 }
1631 };
1632
1633 class DestroyField final : public EHScopeStack::Cleanup {
1634 const FieldDecl *field;
1635 CodeGenFunction::Destroyer *destroyer;
1636 bool useEHCleanupForArray;
1637
1638 public:
1639 DestroyField(const FieldDecl *field, CodeGenFunction::Destroyer *destroyer,
1640 bool useEHCleanupForArray)
1641 : field(field), destroyer(destroyer),
1642 useEHCleanupForArray(useEHCleanupForArray) {}
1643
1644 void Emit(CodeGenFunction &CGF, Flags flags) override {
1645 // Find the address of the field.
1646 Address thisValue = CGF.LoadCXXThisAddress();
1647 QualType RecordTy = CGF.getContext().getTagDeclType(field->getParent());
1648 LValue ThisLV = CGF.MakeAddrLValue(thisValue, RecordTy);
1649 LValue LV = CGF.EmitLValueForField(ThisLV, field);
1650 assert(LV.isSimple());
1651
1652 CGF.emitDestroy(LV.getAddress(CGF), field->getType(), destroyer,
1653 flags.isForNormalCleanup() && useEHCleanupForArray);
1654 }
1655 };
1656
1657 static void EmitSanitizerDtorCallback(CodeGenFunction &CGF, llvm::Value *Ptr,
1658 CharUnits::QuantityType PoisonSize) {
1659 CodeGenFunction::SanitizerScope SanScope(&CGF);
1660 // Pass in void pointer and size of region as arguments to runtime
1661 // function
1662 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(Ptr, CGF.VoidPtrTy),
1663 llvm::ConstantInt::get(CGF.SizeTy, PoisonSize)};
1664
1665 llvm::Type *ArgTypes[] = {CGF.VoidPtrTy, CGF.SizeTy};
1666
1667 llvm::FunctionType *FnType =
1668 llvm::FunctionType::get(CGF.VoidTy, ArgTypes, false);
1669 llvm::FunctionCallee Fn =
1670 CGF.CGM.CreateRuntimeFunction(FnType, "__sanitizer_dtor_callback");
1671 CGF.EmitNounwindRuntimeCall(Fn, Args);
1672 }
1673
1674 class SanitizeDtorMembers final : public EHScopeStack::Cleanup {
1675 const CXXDestructorDecl *Dtor;
1676
1677 public:
1678 SanitizeDtorMembers(const CXXDestructorDecl *Dtor) : Dtor(Dtor) {}
1679
1680 // Generate function call for handling object poisoning.
1681 // Disables tail call elimination, to prevent the current stack frame
1682 // from disappearing from the stack trace.
1683 void Emit(CodeGenFunction &CGF, Flags flags) override {
1684 const ASTRecordLayout &Layout =
1685 CGF.getContext().getASTRecordLayout(Dtor->getParent());
1686
1687 // Nothing to poison.
1688 if (Layout.getFieldCount() == 0)
1689 return;
1690
1691 // Prevent the current stack frame from disappearing from the stack trace.
1692 CGF.CurFn->addFnAttr("disable-tail-calls", "true");
1693
1694 // Construct pointer to region to begin poisoning, and calculate poison
1695 // size, so that only members declared in this class are poisoned.
1696 ASTContext &Context = CGF.getContext();
1697
1698 const RecordDecl *Decl = Dtor->getParent();
1699 auto Fields = Decl->fields();
1700 auto IsTrivial = [&](const FieldDecl *F) {
1701 return FieldHasTrivialDestructorBody(Context, F);
1702 };
1703
1704 auto IsZeroSize = [&](const FieldDecl *F) {
1705 return F->isZeroSize(Context);
1706 };
1707
1708 // Poison blocks of fields with trivial destructors making sure that block
1709 // begin and end do not point to zero-sized fields. They don't have
1710 // correct offsets so can't be used to calculate poisoning range.
1711 for (auto It = Fields.begin(); It != Fields.end();) {
1712 It = std::find_if(It, Fields.end(), [&](const FieldDecl *F) {
1713 return IsTrivial(F) && !IsZeroSize(F);
1714 });
1715 if (It == Fields.end())
1716 break;
1717 auto Start = It++;
1718 It = std::find_if(It, Fields.end(), [&](const FieldDecl *F) {
1719 return !IsTrivial(F) && !IsZeroSize(F);
1720 });
1721
1722 PoisonMembers(CGF, (*Start)->getFieldIndex(),
1723 It == Fields.end() ? -1 : (*It)->getFieldIndex());
1724 }
1725 }
1726
1727 private:
1728 /// \param layoutStartOffset index of the ASTRecordLayout field to
1729 /// start poisoning (inclusive)
1730 /// \param layoutEndOffset index of the ASTRecordLayout field to
1731 /// end poisoning (exclusive)
1732 void PoisonMembers(CodeGenFunction &CGF, unsigned layoutStartOffset,
1733 unsigned layoutEndOffset) {
1734 ASTContext &Context = CGF.getContext();
1735 const ASTRecordLayout &Layout =
1736 Context.getASTRecordLayout(Dtor->getParent());
1737
1738 // It's a first trivia field so it should be at the begining of char,
1739 // still round up start offset just in case.
1740 CharUnits PoisonStart =
1741 Context.toCharUnitsFromBits(Layout.getFieldOffset(layoutStartOffset) +
1742 Context.getCharWidth() - 1);
1743 llvm::ConstantInt *OffsetSizePtr =
1744 llvm::ConstantInt::get(CGF.SizeTy, PoisonStart.getQuantity());
1745
1746 llvm::Value *OffsetPtr = CGF.Builder.CreateGEP(
1747 CGF.Builder.CreateBitCast(CGF.LoadCXXThis(), CGF.Int8PtrTy),
1748 OffsetSizePtr);
1749
1750 CharUnits PoisonEnd;
1751 if (layoutEndOffset >= Layout.getFieldCount()) {
1752 PoisonEnd = Layout.getNonVirtualSize();
1753 } else {
1754 PoisonEnd =
1755 Context.toCharUnitsFromBits(Layout.getFieldOffset(layoutEndOffset));
1756 }
1757 CharUnits PoisonSize = PoisonEnd - PoisonStart;
1758 if (!PoisonSize.isPositive())
1759 return;
1760
1761 EmitSanitizerDtorCallback(CGF, OffsetPtr, PoisonSize.getQuantity());
1762 }
1763 };
1764
1765 class SanitizeDtorVTable final : public EHScopeStack::Cleanup {
1766 const CXXDestructorDecl *Dtor;
1767
1768 public:
1769 SanitizeDtorVTable(const CXXDestructorDecl *Dtor) : Dtor(Dtor) {}
1770
1771 // Generate function call for handling vtable pointer poisoning.
1772 void Emit(CodeGenFunction &CGF, Flags flags) override {
1773 assert(Dtor->getParent()->isDynamicClass());
1774 (void)Dtor;
1775 ASTContext &Context = CGF.getContext();
1776 // Poison vtable and vtable ptr if they exist for this class.
1777 llvm::Value *VTablePtr = CGF.LoadCXXThis();
1778
1779 CharUnits::QuantityType PoisonSize =
1780 Context.toCharUnitsFromBits(CGF.PointerWidthInBits).getQuantity();
1781 // Pass in void pointer and size of region as arguments to runtime
1782 // function
1783 EmitSanitizerDtorCallback(CGF, VTablePtr, PoisonSize);
1784 }
1785 };
1786} // end anonymous namespace
1787
1788/// Emit all code that comes at the end of class's
1789/// destructor. This is to call destructors on members and base classes
1790/// in reverse order of their construction.
1791///
1792/// For a deleting destructor, this also handles the case where a destroying
1793/// operator delete completely overrides the definition.
1794void CodeGenFunction::EnterDtorCleanups(const CXXDestructorDecl *DD,
1795 CXXDtorType DtorType) {
1796 assert((!DD->isTrivial() || DD->hasAttr<DLLExportAttr>()) &&
1797 "Should not emit dtor epilogue for non-exported trivial dtor!");
1798
1799 // The deleting-destructor phase just needs to call the appropriate
1800 // operator delete that Sema picked up.
1801 if (DtorType == Dtor_Deleting) {
1802 assert(DD->getOperatorDelete() &&
1803 "operator delete missing - EnterDtorCleanups");
1804 if (CXXStructorImplicitParamValue) {
1805 // If there is an implicit param to the deleting dtor, it's a boolean
1806 // telling whether this is a deleting destructor.
1807 if (DD->getOperatorDelete()->isDestroyingOperatorDelete())
1808 EmitConditionalDtorDeleteCall(*this, CXXStructorImplicitParamValue,
1809 /*ReturnAfterDelete*/true);
1810 else
1811 EHStack.pushCleanup<CallDtorDeleteConditional>(
1812 NormalAndEHCleanup, CXXStructorImplicitParamValue);
1813 } else {
1814 if (DD->getOperatorDelete()->isDestroyingOperatorDelete()) {
1815 const CXXRecordDecl *ClassDecl = DD->getParent();
1816 EmitDeleteCall(DD->getOperatorDelete(),
1817 LoadThisForDtorDelete(*this, DD),
1818 getContext().getTagDeclType(ClassDecl));
1819 EmitBranchThroughCleanup(ReturnBlock);
1820 } else {
1821 EHStack.pushCleanup<CallDtorDelete>(NormalAndEHCleanup);
1822 }
1823 }
1824 return;
1825 }
1826
1827 const CXXRecordDecl *ClassDecl = DD->getParent();
1828
1829 // Unions have no bases and do not call field destructors.
1830 if (ClassDecl->isUnion())
1831 return;
1832
1833 // The complete-destructor phase just destructs all the virtual bases.
1834 if (DtorType == Dtor_Complete) {
1835 // Poison the vtable pointer such that access after the base
1836 // and member destructors are invoked is invalid.
1837 if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor &&
1838 SanOpts.has(SanitizerKind::Memory) && ClassDecl->getNumVBases() &&
1839 ClassDecl->isPolymorphic())
1840 EHStack.pushCleanup<SanitizeDtorVTable>(NormalAndEHCleanup, DD);
1841
1842 // We push them in the forward order so that they'll be popped in
1843 // the reverse order.
1844 for (const auto &Base : ClassDecl->vbases()) {
1845 auto *BaseClassDecl =
1846 cast<CXXRecordDecl>(Base.getType()->castAs<RecordType>()->getDecl());
1847
1848 // Ignore trivial destructors.
1849 if (BaseClassDecl->hasTrivialDestructor())
1850 continue;
1851
1852 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1853 BaseClassDecl,
1854 /*BaseIsVirtual*/ true);
1855 }
1856
1857 return;
1858 }
1859
1860 assert(DtorType == Dtor_Base);
1861 // Poison the vtable pointer if it has no virtual bases, but inherits
1862 // virtual functions.
1863 if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor &&
1864 SanOpts.has(SanitizerKind::Memory) && !ClassDecl->getNumVBases() &&
1865 ClassDecl->isPolymorphic())
1866 EHStack.pushCleanup<SanitizeDtorVTable>(NormalAndEHCleanup, DD);
1867
1868 // Destroy non-virtual bases.
1869 for (const auto &Base : ClassDecl->bases()) {
1870 // Ignore virtual bases.
1871 if (Base.isVirtual())
1872 continue;
1873
1874 CXXRecordDecl *BaseClassDecl = Base.getType()->getAsCXXRecordDecl();
1875
1876 // Ignore trivial destructors.
1877 if (BaseClassDecl->hasTrivialDestructor())
1878 continue;
1879
1880 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1881 BaseClassDecl,
1882 /*BaseIsVirtual*/ false);
1883 }
1884
1885 // Poison fields such that access after their destructors are
1886 // invoked, and before the base class destructor runs, is invalid.
1887 if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor &&
1888 SanOpts.has(SanitizerKind::Memory))
1889 EHStack.pushCleanup<SanitizeDtorMembers>(NormalAndEHCleanup, DD);
1890
1891 // Destroy direct fields.
1892 for (const auto *Field : ClassDecl->fields()) {
1893 QualType type = Field->getType();
1894 QualType::DestructionKind dtorKind = type.isDestructedType();
1895 if (!dtorKind) continue;
1896
1897 // Anonymous union members do not have their destructors called.
1898 const RecordType *RT = type->getAsUnionType();
1899 if (RT && RT->getDecl()->isAnonymousStructOrUnion()) continue;
1900
1901 CleanupKind cleanupKind = getCleanupKind(dtorKind);
1902 EHStack.pushCleanup<DestroyField>(cleanupKind, Field,
1903 getDestroyer(dtorKind),
1904 cleanupKind & EHCleanup);
1905 }
1906}
1907
1908/// EmitCXXAggrConstructorCall - Emit a loop to call a particular
1909/// constructor for each of several members of an array.
1910///
1911/// \param ctor the constructor to call for each element
1912/// \param arrayType the type of the array to initialize
1913/// \param arrayBegin an arrayType*
1914/// \param zeroInitialize true if each element should be
1915/// zero-initialized before it is constructed
1916void CodeGenFunction::EmitCXXAggrConstructorCall(
1917 const CXXConstructorDecl *ctor, const ArrayType *arrayType,
1918 Address arrayBegin, const CXXConstructExpr *E, bool NewPointerIsChecked,
1919 bool zeroInitialize) {
1920 QualType elementType;
1921 llvm::Value *numElements =
1922 emitArrayLength(arrayType, elementType, arrayBegin);
1923
1924 EmitCXXAggrConstructorCall(ctor, numElements, arrayBegin, E,
1925 NewPointerIsChecked, zeroInitialize);
1926}
1927
1928/// EmitCXXAggrConstructorCall - Emit a loop to call a particular
1929/// constructor for each of several members of an array.
1930///
1931/// \param ctor the constructor to call for each element
1932/// \param numElements the number of elements in the array;
1933/// may be zero
1934/// \param arrayBase a T*, where T is the type constructed by ctor
1935/// \param zeroInitialize true if each element should be
1936/// zero-initialized before it is constructed
1937void CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor,
1938 llvm::Value *numElements,
1939 Address arrayBase,
1940 const CXXConstructExpr *E,
1941 bool NewPointerIsChecked,
1942 bool zeroInitialize) {
1943 // It's legal for numElements to be zero. This can happen both
1944 // dynamically, because x can be zero in 'new A[x]', and statically,
1945 // because of GCC extensions that permit zero-length arrays. There
1946 // are probably legitimate places where we could assume that this
1947 // doesn't happen, but it's not clear that it's worth it.
1948 llvm::BranchInst *zeroCheckBranch = nullptr;
1949
1950 // Optimize for a constant count.
1951 llvm::ConstantInt *constantCount
1952 = dyn_cast<llvm::ConstantInt>(numElements);
1953 if (constantCount) {
1954 // Just skip out if the constant count is zero.
1955 if (constantCount->isZero()) return;
1956
1957 // Otherwise, emit the check.
1958 } else {
1959 llvm::BasicBlock *loopBB = createBasicBlock("new.ctorloop");
1960 llvm::Value *iszero = Builder.CreateIsNull(numElements, "isempty");
1961 zeroCheckBranch = Builder.CreateCondBr(iszero, loopBB, loopBB);
1962 EmitBlock(loopBB);
1963 }
1964
1965 // Find the end of the array.
1966 llvm::Type *elementType = arrayBase.getElementType();
1967 llvm::Value *arrayBegin = arrayBase.getPointer();
1968 llvm::Value *arrayEnd = Builder.CreateInBoundsGEP(
1969 elementType, arrayBegin, numElements, "arrayctor.end");
1970
1971 // Enter the loop, setting up a phi for the current location to initialize.
1972 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1973 llvm::BasicBlock *loopBB = createBasicBlock("arrayctor.loop");
1974 EmitBlock(loopBB);
1975 llvm::PHINode *cur = Builder.CreatePHI(arrayBegin->getType(), 2,
1976 "arrayctor.cur");
1977 cur->addIncoming(arrayBegin, entryBB);
1978
1979 // Inside the loop body, emit the constructor call on the array element.
1980
1981 // The alignment of the base, adjusted by the size of a single element,
1982 // provides a conservative estimate of the alignment of every element.
1983 // (This assumes we never start tracking offsetted alignments.)
1984 //
1985 // Note that these are complete objects and so we don't need to
1986 // use the non-virtual size or alignment.
1987 QualType type = getContext().getTypeDeclType(ctor->getParent());
1988 CharUnits eltAlignment =
1989 arrayBase.getAlignment()
1990 .alignmentOfArrayElement(getContext().getTypeSizeInChars(type));
1991 Address curAddr = Address(cur, eltAlignment);
1992
1993 // Zero initialize the storage, if requested.
1994 if (zeroInitialize)
1995 EmitNullInitialization(curAddr, type);
1996
1997 // C++ [class.temporary]p4:
1998 // There are two contexts in which temporaries are destroyed at a different
1999 // point than the end of the full-expression. The first context is when a
2000 // default constructor is called to initialize an element of an array.
2001 // If the constructor has one or more default arguments, the destruction of
2002 // every temporary created in a default argument expression is sequenced
2003 // before the construction of the next array element, if any.
2004
2005 {
2006 RunCleanupsScope Scope(*this);
2007
2008 // Evaluate the constructor and its arguments in a regular
2009 // partial-destroy cleanup.
2010 if (getLangOpts().Exceptions &&
2011 !ctor->getParent()->hasTrivialDestructor()) {
2012 Destroyer *destroyer = destroyCXXObject;
2013 pushRegularPartialArrayCleanup(arrayBegin, cur, type, eltAlignment,
2014 *destroyer);
2015 }
2016 auto currAVS = AggValueSlot::forAddr(
2017 curAddr, type.getQualifiers(), AggValueSlot::IsDestructed,
2018 AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased,
2019 AggValueSlot::DoesNotOverlap, AggValueSlot::IsNotZeroed,
2020 NewPointerIsChecked ? AggValueSlot::IsSanitizerChecked
2021 : AggValueSlot::IsNotSanitizerChecked);
2022 EmitCXXConstructorCall(ctor, Ctor_Complete, /*ForVirtualBase=*/false,
2023 /*Delegating=*/false, currAVS, E);
2024 }
2025
2026 // Go to the next element.
2027 llvm::Value *next = Builder.CreateInBoundsGEP(
2028 elementType, cur, llvm::ConstantInt::get(SizeTy, 1), "arrayctor.next");
2029 cur->addIncoming(next, Builder.GetInsertBlock());
2030
2031 // Check whether that's the end of the loop.
2032 llvm::Value *done = Builder.CreateICmpEQ(next, arrayEnd, "arrayctor.done");
2033 llvm::BasicBlock *contBB = createBasicBlock("arrayctor.cont");
2034 Builder.CreateCondBr(done, contBB, loopBB);
2035
2036 // Patch the earlier check to skip over the loop.
2037 if (zeroCheckBranch) zeroCheckBranch->setSuccessor(0, contBB);
2038
2039 EmitBlock(contBB);
2040}
2041
2042void CodeGenFunction::destroyCXXObject(CodeGenFunction &CGF,
2043 Address addr,
2044 QualType type) {
2045 const RecordType *rtype = type->castAs<RecordType>();
2046 const CXXRecordDecl *record = cast<CXXRecordDecl>(rtype->getDecl());
2047 const CXXDestructorDecl *dtor = record->getDestructor();
2048 assert(!dtor->isTrivial());
2049 CGF.EmitCXXDestructorCall(dtor, Dtor_Complete, /*for vbase*/ false,
2050 /*Delegating=*/false, addr, type);
2051}
2052
2053void CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
2054 CXXCtorType Type,
2055 bool ForVirtualBase,
2056 bool Delegating,
2057 AggValueSlot ThisAVS,
2058 const CXXConstructExpr *E) {
2059 CallArgList Args;
2060 Address This = ThisAVS.getAddress();
2061 LangAS SlotAS = ThisAVS.getQualifiers().getAddressSpace();
2062 QualType ThisType = D->getThisType();
2063 LangAS ThisAS = ThisType.getTypePtr()->getPointeeType().getAddressSpace();
2064 llvm::Value *ThisPtr = This.getPointer();
2065
2066 if (SlotAS != ThisAS) {
2067 unsigned TargetThisAS = getContext().getTargetAddressSpace(ThisAS);
2068 llvm::Type *NewType =
2069 ThisPtr->getType()->getPointerElementType()->getPointerTo(TargetThisAS);
2070 ThisPtr = getTargetHooks().performAddrSpaceCast(*this, This.getPointer(),
2071 ThisAS, SlotAS, NewType);
2072 }
2073
2074 // Push the this ptr.
2075 Args.add(RValue::get(ThisPtr), D->getThisType());
2076
2077 // If this is a trivial constructor, emit a memcpy now before we lose
2078 // the alignment information on the argument.
2079 // FIXME: It would be better to preserve alignment information into CallArg.
2080 if (isMemcpyEquivalentSpecialMember(D)) {
2081 assert(E->getNumArgs() == 1 && "unexpected argcount for trivial ctor");
2082
2083 const Expr *Arg = E->getArg(0);
2084 LValue Src = EmitLValue(Arg);
2085 QualType DestTy = getContext().getTypeDeclType(D->getParent());
2086 LValue Dest = MakeAddrLValue(This, DestTy);
2087 EmitAggregateCopyCtor(Dest, Src, ThisAVS.mayOverlap());
2088 return;
2089 }
2090
2091 // Add the rest of the user-supplied arguments.
2092 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
2093 EvaluationOrder Order = E->isListInitialization()
2094 ? EvaluationOrder::ForceLeftToRight
2095 : EvaluationOrder::Default;
2096 EmitCallArgs(Args, FPT, E->arguments(), E->getConstructor(),
2097 /*ParamsToSkip*/ 0, Order);
2098
2099 EmitCXXConstructorCall(D, Type, ForVirtualBase, Delegating, This, Args,
2100 ThisAVS.mayOverlap(), E->getExprLoc(),
2101 ThisAVS.isSanitizerChecked());
2102}
2103
2104static bool canEmitDelegateCallArgs(CodeGenFunction &CGF,
2105 const CXXConstructorDecl *Ctor,
2106 CXXCtorType Type, CallArgList &Args) {
2107 // We can't forward a variadic call.
2108 if (Ctor->isVariadic())
2109 return false;
2110
2111 if (CGF.getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) {
2112 // If the parameters are callee-cleanup, it's not safe to forward.
2113 for (auto *P : Ctor->parameters())
2114 if (P->needsDestruction(CGF.getContext()))
2115 return false;
2116
2117 // Likewise if they're inalloca.
2118 const CGFunctionInfo &Info =
2119 CGF.CGM.getTypes().arrangeCXXConstructorCall(Args, Ctor, Type, 0, 0);
2120 if (Info.usesInAlloca())
2121 return false;
2122 }
2123
2124 // Anything else should be OK.
2125 return true;
2126}
2127
2128void CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
2129 CXXCtorType Type,
2130 bool ForVirtualBase,
2131 bool Delegating,
2132 Address This,
2133 CallArgList &Args,
2134 AggValueSlot::Overlap_t Overlap,
2135 SourceLocation Loc,
2136 bool NewPointerIsChecked) {
2137 const CXXRecordDecl *ClassDecl = D->getParent();
2138
2139 if (!NewPointerIsChecked)
2140 EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall, Loc, This.getPointer(),
2141 getContext().getRecordType(ClassDecl), CharUnits::Zero());
2142
2143 if (D->isTrivial() && D->isDefaultConstructor()) {
2144 assert(Args.size() == 1 && "trivial default ctor with args");
2145 return;
2146 }
2147
2148 // If this is a trivial constructor, just emit what's needed. If this is a
2149 // union copy constructor, we must emit a memcpy, because the AST does not
2150 // model that copy.
2151 if (isMemcpyEquivalentSpecialMember(D)) {
2152 assert(Args.size() == 2 && "unexpected argcount for trivial ctor");
2153
2154 QualType SrcTy = D->getParamDecl(0)->getType().getNonReferenceType();
2155 Address Src(Args[1].getRValue(*this).getScalarVal(),
2156 CGM.getNaturalTypeAlignment(SrcTy));
2157 LValue SrcLVal = MakeAddrLValue(Src, SrcTy);
2158 QualType DestTy = getContext().getTypeDeclType(ClassDecl);
2159 LValue DestLVal = MakeAddrLValue(This, DestTy);
2160 EmitAggregateCopyCtor(DestLVal, SrcLVal, Overlap);
2161 return;
2162 }
2163
2164 bool PassPrototypeArgs = true;
2165 // Check whether we can actually emit the constructor before trying to do so.
2166 if (auto Inherited = D->getInheritedConstructor()) {
2167 PassPrototypeArgs = getTypes().inheritingCtorHasParams(Inherited, Type);
2168 if (PassPrototypeArgs && !canEmitDelegateCallArgs(*this, D, Type, Args)) {
2169 EmitInlinedInheritingCXXConstructorCall(D, Type, ForVirtualBase,
2170 Delegating, Args);
2171 return;
2172 }
2173 }
2174
2175 // Insert any ABI-specific implicit constructor arguments.
2176 CGCXXABI::AddedStructorArgCounts ExtraArgs =
2177 CGM.getCXXABI().addImplicitConstructorArgs(*this, D, Type, ForVirtualBase,
2178 Delegating, Args);
2179
2180 // Emit the call.
2181 llvm::Constant *CalleePtr = CGM.getAddrOfCXXStructor(GlobalDecl(D, Type));
2182 const CGFunctionInfo &Info = CGM.getTypes().arrangeCXXConstructorCall(
2183 Args, D, Type, ExtraArgs.Prefix, ExtraArgs.Suffix, PassPrototypeArgs);
2184 CGCallee Callee = CGCallee::forDirect(CalleePtr, GlobalDecl(D, Type));
2185