1 //===--- CGClass.cpp - Emit LLVM Code for C++ classes -----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This contains code dealing with C++ code generation of classes
12 //===----------------------------------------------------------------------===//
16 #include "CGDebugInfo.h"
17 #include "CGRecordLayout.h"
18 #include "CodeGenFunction.h"
19 #include "clang/AST/CXXInheritance.h"
20 #include "clang/AST/DeclTemplate.h"
21 #include "clang/AST/EvaluatedExprVisitor.h"
22 #include "clang/AST/RecordLayout.h"
23 #include "clang/AST/StmtCXX.h"
24 #include "clang/Basic/TargetBuiltins.h"
25 #include "clang/CodeGen/CGFunctionInfo.h"
26 #include "clang/Frontend/CodeGenOptions.h"
27 #include "llvm/IR/Intrinsics.h"
28 #include "llvm/IR/Metadata.h"
29 #include "llvm/Transforms/Utils/SanitizerStats.h"
31 using namespace clang;
32 using namespace CodeGen;
34 /// Return the best known alignment for an unknown pointer to a
36 CharUnits CodeGenModule::getClassPointerAlignment(const CXXRecordDecl *RD) {
37 if (!RD->isCompleteDefinition())
38 return CharUnits::One(); // Hopefully won't be used anywhere.
40 auto &layout = getContext().getASTRecordLayout(RD);
42 // If the class is final, then we know that the pointer points to an
43 // object of that type and can use the full alignment.
44 if (RD->hasAttr<FinalAttr>()) {
45 return layout.getAlignment();
47 // Otherwise, we have to assume it could be a subclass.
49 return layout.getNonVirtualAlignment();
53 /// Return the best known alignment for a pointer to a virtual base,
54 /// given the alignment of a pointer to the derived class.
55 CharUnits CodeGenModule::getVBaseAlignment(CharUnits actualDerivedAlign,
56 const CXXRecordDecl *derivedClass,
57 const CXXRecordDecl *vbaseClass) {
58 // The basic idea here is that an underaligned derived pointer might
59 // indicate an underaligned base pointer.
61 assert(vbaseClass->isCompleteDefinition());
62 auto &baseLayout = getContext().getASTRecordLayout(vbaseClass);
63 CharUnits expectedVBaseAlign = baseLayout.getNonVirtualAlignment();
65 return getDynamicOffsetAlignment(actualDerivedAlign, derivedClass,
70 CodeGenModule::getDynamicOffsetAlignment(CharUnits actualBaseAlign,
71 const CXXRecordDecl *baseDecl,
72 CharUnits expectedTargetAlign) {
73 // If the base is an incomplete type (which is, alas, possible with
74 // member pointers), be pessimistic.
75 if (!baseDecl->isCompleteDefinition())
76 return std::min(actualBaseAlign, expectedTargetAlign);
78 auto &baseLayout = getContext().getASTRecordLayout(baseDecl);
79 CharUnits expectedBaseAlign = baseLayout.getNonVirtualAlignment();
81 // If the class is properly aligned, assume the target offset is, too.
83 // This actually isn't necessarily the right thing to do --- if the
84 // class is a complete object, but it's only properly aligned for a
85 // base subobject, then the alignments of things relative to it are
86 // probably off as well. (Note that this requires the alignment of
87 // the target to be greater than the NV alignment of the derived
90 // However, our approach to this kind of under-alignment can only
91 // ever be best effort; after all, we're never going to propagate
92 // alignments through variables or parameters. Note, in particular,
93 // that constructing a polymorphic type in an address that's less
94 // than pointer-aligned will generally trap in the constructor,
95 // unless we someday add some sort of attribute to change the
96 // assumed alignment of 'this'. So our goal here is pretty much
97 // just to allow the user to explicitly say that a pointer is
98 // under-aligned and then safely access its fields and vtables.
99 if (actualBaseAlign >= expectedBaseAlign) {
100 return expectedTargetAlign;
103 // Otherwise, we might be offset by an arbitrary multiple of the
104 // actual alignment. The correct adjustment is to take the min of
105 // the two alignments.
106 return std::min(actualBaseAlign, expectedTargetAlign);
109 Address CodeGenFunction::LoadCXXThisAddress() {
110 assert(CurFuncDecl && "loading 'this' without a func declaration?");
111 assert(isa<CXXMethodDecl>(CurFuncDecl));
113 // Lazily compute CXXThisAlignment.
114 if (CXXThisAlignment.isZero()) {
115 // Just use the best known alignment for the parent.
116 // TODO: if we're currently emitting a complete-object ctor/dtor,
117 // we can always use the complete-object alignment.
118 auto RD = cast<CXXMethodDecl>(CurFuncDecl)->getParent();
119 CXXThisAlignment = CGM.getClassPointerAlignment(RD);
122 return Address(LoadCXXThis(), CXXThisAlignment);
125 /// Emit the address of a field using a member data pointer.
127 /// \param E Only used for emergency diagnostics
129 CodeGenFunction::EmitCXXMemberDataPointerAddress(const Expr *E, Address base,
130 llvm::Value *memberPtr,
131 const MemberPointerType *memberPtrType,
132 LValueBaseInfo *BaseInfo) {
133 // Ask the ABI to compute the actual address.
135 CGM.getCXXABI().EmitMemberDataPointerAddress(*this, E, base,
136 memberPtr, memberPtrType);
138 QualType memberType = memberPtrType->getPointeeType();
139 CharUnits memberAlign = getNaturalTypeAlignment(memberType, BaseInfo);
141 CGM.getDynamicOffsetAlignment(base.getAlignment(),
142 memberPtrType->getClass()->getAsCXXRecordDecl(),
144 return Address(ptr, memberAlign);
147 CharUnits CodeGenModule::computeNonVirtualBaseClassOffset(
148 const CXXRecordDecl *DerivedClass, CastExpr::path_const_iterator Start,
149 CastExpr::path_const_iterator End) {
150 CharUnits Offset = CharUnits::Zero();
152 const ASTContext &Context = getContext();
153 const CXXRecordDecl *RD = DerivedClass;
155 for (CastExpr::path_const_iterator I = Start; I != End; ++I) {
156 const CXXBaseSpecifier *Base = *I;
157 assert(!Base->isVirtual() && "Should not see virtual bases here!");
160 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
162 const CXXRecordDecl *BaseDecl =
163 cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
166 Offset += Layout.getBaseClassOffset(BaseDecl);
175 CodeGenModule::GetNonVirtualBaseClassOffset(const CXXRecordDecl *ClassDecl,
176 CastExpr::path_const_iterator PathBegin,
177 CastExpr::path_const_iterator PathEnd) {
178 assert(PathBegin != PathEnd && "Base path should not be empty!");
181 computeNonVirtualBaseClassOffset(ClassDecl, PathBegin, PathEnd);
185 llvm::Type *PtrDiffTy =
186 Types.ConvertType(getContext().getPointerDiffType());
188 return llvm::ConstantInt::get(PtrDiffTy, Offset.getQuantity());
191 /// Gets the address of a direct base class within a complete object.
192 /// This should only be used for (1) non-virtual bases or (2) virtual bases
193 /// when the type is known to be complete (e.g. in complete destructors).
195 /// The object pointed to by 'This' is assumed to be non-null.
197 CodeGenFunction::GetAddressOfDirectBaseInCompleteClass(Address This,
198 const CXXRecordDecl *Derived,
199 const CXXRecordDecl *Base,
200 bool BaseIsVirtual) {
201 // 'this' must be a pointer (in some address space) to Derived.
202 assert(This.getElementType() == ConvertType(Derived));
204 // Compute the offset of the virtual base.
206 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(Derived);
208 Offset = Layout.getVBaseClassOffset(Base);
210 Offset = Layout.getBaseClassOffset(Base);
212 // Shift and cast down to the base type.
213 // TODO: for complete types, this should be possible with a GEP.
215 if (!Offset.isZero()) {
216 V = Builder.CreateElementBitCast(V, Int8Ty);
217 V = Builder.CreateConstInBoundsByteGEP(V, Offset);
219 V = Builder.CreateElementBitCast(V, ConvertType(Base));
225 ApplyNonVirtualAndVirtualOffset(CodeGenFunction &CGF, Address addr,
226 CharUnits nonVirtualOffset,
227 llvm::Value *virtualOffset,
228 const CXXRecordDecl *derivedClass,
229 const CXXRecordDecl *nearestVBase) {
230 // Assert that we have something to do.
231 assert(!nonVirtualOffset.isZero() || virtualOffset != nullptr);
233 // Compute the offset from the static and dynamic components.
234 llvm::Value *baseOffset;
235 if (!nonVirtualOffset.isZero()) {
236 baseOffset = llvm::ConstantInt::get(CGF.PtrDiffTy,
237 nonVirtualOffset.getQuantity());
239 baseOffset = CGF.Builder.CreateAdd(virtualOffset, baseOffset);
242 baseOffset = virtualOffset;
245 // Apply the base offset.
246 llvm::Value *ptr = addr.getPointer();
247 ptr = CGF.Builder.CreateBitCast(ptr, CGF.Int8PtrTy);
248 ptr = CGF.Builder.CreateInBoundsGEP(ptr, baseOffset, "add.ptr");
250 // If we have a virtual component, the alignment of the result will
251 // be relative only to the known alignment of that vbase.
254 assert(nearestVBase && "virtual offset without vbase?");
255 alignment = CGF.CGM.getVBaseAlignment(addr.getAlignment(),
256 derivedClass, nearestVBase);
258 alignment = addr.getAlignment();
260 alignment = alignment.alignmentAtOffset(nonVirtualOffset);
262 return Address(ptr, alignment);
265 Address CodeGenFunction::GetAddressOfBaseClass(
266 Address Value, const CXXRecordDecl *Derived,
267 CastExpr::path_const_iterator PathBegin,
268 CastExpr::path_const_iterator PathEnd, bool NullCheckValue,
269 SourceLocation Loc) {
270 assert(PathBegin != PathEnd && "Base path should not be empty!");
272 CastExpr::path_const_iterator Start = PathBegin;
273 const CXXRecordDecl *VBase = nullptr;
275 // Sema has done some convenient canonicalization here: if the
276 // access path involved any virtual steps, the conversion path will
277 // *start* with a step down to the correct virtual base subobject,
278 // and hence will not require any further steps.
279 if ((*Start)->isVirtual()) {
281 cast<CXXRecordDecl>((*Start)->getType()->getAs<RecordType>()->getDecl());
285 // Compute the static offset of the ultimate destination within its
286 // allocating subobject (the virtual base, if there is one, or else
287 // the "complete" object that we see).
288 CharUnits NonVirtualOffset = CGM.computeNonVirtualBaseClassOffset(
289 VBase ? VBase : Derived, Start, PathEnd);
291 // If there's a virtual step, we can sometimes "devirtualize" it.
292 // For now, that's limited to when the derived type is final.
293 // TODO: "devirtualize" this for accesses to known-complete objects.
294 if (VBase && Derived->hasAttr<FinalAttr>()) {
295 const ASTRecordLayout &layout = getContext().getASTRecordLayout(Derived);
296 CharUnits vBaseOffset = layout.getVBaseClassOffset(VBase);
297 NonVirtualOffset += vBaseOffset;
298 VBase = nullptr; // we no longer have a virtual step
301 // Get the base pointer type.
302 llvm::Type *BasePtrTy =
303 ConvertType((PathEnd[-1])->getType())->getPointerTo();
305 QualType DerivedTy = getContext().getRecordType(Derived);
306 CharUnits DerivedAlign = CGM.getClassPointerAlignment(Derived);
308 // If the static offset is zero and we don't have a virtual step,
309 // just do a bitcast; null checks are unnecessary.
310 if (NonVirtualOffset.isZero() && !VBase) {
311 if (sanitizePerformTypeCheck()) {
312 SanitizerSet SkippedChecks;
313 SkippedChecks.set(SanitizerKind::Null, !NullCheckValue);
314 EmitTypeCheck(TCK_Upcast, Loc, Value.getPointer(),
315 DerivedTy, DerivedAlign, SkippedChecks);
317 return Builder.CreateBitCast(Value, BasePtrTy);
320 llvm::BasicBlock *origBB = nullptr;
321 llvm::BasicBlock *endBB = nullptr;
323 // Skip over the offset (and the vtable load) if we're supposed to
324 // null-check the pointer.
325 if (NullCheckValue) {
326 origBB = Builder.GetInsertBlock();
327 llvm::BasicBlock *notNullBB = createBasicBlock("cast.notnull");
328 endBB = createBasicBlock("cast.end");
330 llvm::Value *isNull = Builder.CreateIsNull(Value.getPointer());
331 Builder.CreateCondBr(isNull, endBB, notNullBB);
332 EmitBlock(notNullBB);
335 if (sanitizePerformTypeCheck()) {
336 SanitizerSet SkippedChecks;
337 SkippedChecks.set(SanitizerKind::Null, true);
338 EmitTypeCheck(VBase ? TCK_UpcastToVirtualBase : TCK_Upcast, Loc,
339 Value.getPointer(), DerivedTy, DerivedAlign, SkippedChecks);
342 // Compute the virtual offset.
343 llvm::Value *VirtualOffset = nullptr;
346 CGM.getCXXABI().GetVirtualBaseClassOffset(*this, Value, Derived, VBase);
349 // Apply both offsets.
350 Value = ApplyNonVirtualAndVirtualOffset(*this, Value, NonVirtualOffset,
351 VirtualOffset, Derived, VBase);
353 // Cast to the destination type.
354 Value = Builder.CreateBitCast(Value, BasePtrTy);
356 // Build a phi if we needed a null check.
357 if (NullCheckValue) {
358 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
359 Builder.CreateBr(endBB);
362 llvm::PHINode *PHI = Builder.CreatePHI(BasePtrTy, 2, "cast.result");
363 PHI->addIncoming(Value.getPointer(), notNullBB);
364 PHI->addIncoming(llvm::Constant::getNullValue(BasePtrTy), origBB);
365 Value = Address(PHI, Value.getAlignment());
372 CodeGenFunction::GetAddressOfDerivedClass(Address BaseAddr,
373 const CXXRecordDecl *Derived,
374 CastExpr::path_const_iterator PathBegin,
375 CastExpr::path_const_iterator PathEnd,
376 bool NullCheckValue) {
377 assert(PathBegin != PathEnd && "Base path should not be empty!");
380 getContext().getCanonicalType(getContext().getTagDeclType(Derived));
381 llvm::Type *DerivedPtrTy = ConvertType(DerivedTy)->getPointerTo();
383 llvm::Value *NonVirtualOffset =
384 CGM.GetNonVirtualBaseClassOffset(Derived, PathBegin, PathEnd);
386 if (!NonVirtualOffset) {
387 // No offset, we can just cast back.
388 return Builder.CreateBitCast(BaseAddr, DerivedPtrTy);
391 llvm::BasicBlock *CastNull = nullptr;
392 llvm::BasicBlock *CastNotNull = nullptr;
393 llvm::BasicBlock *CastEnd = nullptr;
395 if (NullCheckValue) {
396 CastNull = createBasicBlock("cast.null");
397 CastNotNull = createBasicBlock("cast.notnull");
398 CastEnd = createBasicBlock("cast.end");
400 llvm::Value *IsNull = Builder.CreateIsNull(BaseAddr.getPointer());
401 Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
402 EmitBlock(CastNotNull);
406 llvm::Value *Value = Builder.CreateBitCast(BaseAddr.getPointer(), Int8PtrTy);
407 Value = Builder.CreateGEP(Value, Builder.CreateNeg(NonVirtualOffset),
411 Value = Builder.CreateBitCast(Value, DerivedPtrTy);
413 // Produce a PHI if we had a null-check.
414 if (NullCheckValue) {
415 Builder.CreateBr(CastEnd);
417 Builder.CreateBr(CastEnd);
420 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
421 PHI->addIncoming(Value, CastNotNull);
422 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull);
426 return Address(Value, CGM.getClassPointerAlignment(Derived));
429 llvm::Value *CodeGenFunction::GetVTTParameter(GlobalDecl GD,
432 if (!CGM.getCXXABI().NeedsVTTParameter(GD)) {
433 // This constructor/destructor does not need a VTT parameter.
437 const CXXRecordDecl *RD = cast<CXXMethodDecl>(CurCodeDecl)->getParent();
438 const CXXRecordDecl *Base = cast<CXXMethodDecl>(GD.getDecl())->getParent();
442 uint64_t SubVTTIndex;
445 // If this is a delegating constructor call, just load the VTT.
447 } else if (RD == Base) {
448 // If the record matches the base, this is the complete ctor/dtor
449 // variant calling the base variant in a class with virtual bases.
450 assert(!CGM.getCXXABI().NeedsVTTParameter(CurGD) &&
451 "doing no-op VTT offset in base dtor/ctor?");
452 assert(!ForVirtualBase && "Can't have same class as virtual base!");
455 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
456 CharUnits BaseOffset = ForVirtualBase ?
457 Layout.getVBaseClassOffset(Base) :
458 Layout.getBaseClassOffset(Base);
461 CGM.getVTables().getSubVTTIndex(RD, BaseSubobject(Base, BaseOffset));
462 assert(SubVTTIndex != 0 && "Sub-VTT index must be greater than zero!");
465 if (CGM.getCXXABI().NeedsVTTParameter(CurGD)) {
466 // A VTT parameter was passed to the constructor, use it.
468 VTT = Builder.CreateConstInBoundsGEP1_64(VTT, SubVTTIndex);
470 // We're the complete constructor, so get the VTT by name.
471 VTT = CGM.getVTables().GetAddrOfVTT(RD);
472 VTT = Builder.CreateConstInBoundsGEP2_64(VTT, 0, SubVTTIndex);
479 /// Call the destructor for a direct base class.
480 struct CallBaseDtor final : EHScopeStack::Cleanup {
481 const CXXRecordDecl *BaseClass;
483 CallBaseDtor(const CXXRecordDecl *Base, bool BaseIsVirtual)
484 : BaseClass(Base), BaseIsVirtual(BaseIsVirtual) {}
486 void Emit(CodeGenFunction &CGF, Flags flags) override {
487 const CXXRecordDecl *DerivedClass =
488 cast<CXXMethodDecl>(CGF.CurCodeDecl)->getParent();
490 const CXXDestructorDecl *D = BaseClass->getDestructor();
492 CGF.GetAddressOfDirectBaseInCompleteClass(CGF.LoadCXXThisAddress(),
493 DerivedClass, BaseClass,
495 CGF.EmitCXXDestructorCall(D, Dtor_Base, BaseIsVirtual,
496 /*Delegating=*/false, Addr);
500 /// A visitor which checks whether an initializer uses 'this' in a
501 /// way which requires the vtable to be properly set.
502 struct DynamicThisUseChecker : ConstEvaluatedExprVisitor<DynamicThisUseChecker> {
503 typedef ConstEvaluatedExprVisitor<DynamicThisUseChecker> super;
507 DynamicThisUseChecker(const ASTContext &C) : super(C), UsesThis(false) {}
509 // Black-list all explicit and implicit references to 'this'.
511 // Do we need to worry about external references to 'this' derived
512 // from arbitrary code? If so, then anything which runs arbitrary
513 // external code might potentially access the vtable.
514 void VisitCXXThisExpr(const CXXThisExpr *E) { UsesThis = true; }
516 } // end anonymous namespace
518 static bool BaseInitializerUsesThis(ASTContext &C, const Expr *Init) {
519 DynamicThisUseChecker Checker(C);
521 return Checker.UsesThis;
524 static void EmitBaseInitializer(CodeGenFunction &CGF,
525 const CXXRecordDecl *ClassDecl,
526 CXXCtorInitializer *BaseInit,
527 CXXCtorType CtorType) {
528 assert(BaseInit->isBaseInitializer() &&
529 "Must have base initializer!");
531 Address ThisPtr = CGF.LoadCXXThisAddress();
533 const Type *BaseType = BaseInit->getBaseClass();
534 CXXRecordDecl *BaseClassDecl =
535 cast<CXXRecordDecl>(BaseType->getAs<RecordType>()->getDecl());
537 bool isBaseVirtual = BaseInit->isBaseVirtual();
539 // The base constructor doesn't construct virtual bases.
540 if (CtorType == Ctor_Base && isBaseVirtual)
543 // If the initializer for the base (other than the constructor
544 // itself) accesses 'this' in any way, we need to initialize the
546 if (BaseInitializerUsesThis(CGF.getContext(), BaseInit->getInit()))
547 CGF.InitializeVTablePointers(ClassDecl);
549 // We can pretend to be a complete class because it only matters for
550 // virtual bases, and we only do virtual bases for complete ctors.
552 CGF.GetAddressOfDirectBaseInCompleteClass(ThisPtr, ClassDecl,
555 AggValueSlot AggSlot =
556 AggValueSlot::forAddr(V, Qualifiers(),
557 AggValueSlot::IsDestructed,
558 AggValueSlot::DoesNotNeedGCBarriers,
559 AggValueSlot::IsNotAliased);
561 CGF.EmitAggExpr(BaseInit->getInit(), AggSlot);
563 if (CGF.CGM.getLangOpts().Exceptions &&
564 !BaseClassDecl->hasTrivialDestructor())
565 CGF.EHStack.pushCleanup<CallBaseDtor>(EHCleanup, BaseClassDecl,
569 static bool isMemcpyEquivalentSpecialMember(const CXXMethodDecl *D) {
570 auto *CD = dyn_cast<CXXConstructorDecl>(D);
571 if (!(CD && CD->isCopyOrMoveConstructor()) &&
572 !D->isCopyAssignmentOperator() && !D->isMoveAssignmentOperator())
575 // We can emit a memcpy for a trivial copy or move constructor/assignment.
576 if (D->isTrivial() && !D->getParent()->mayInsertExtraPadding())
579 // We *must* emit a memcpy for a defaulted union copy or move op.
580 if (D->getParent()->isUnion() && D->isDefaulted())
586 static void EmitLValueForAnyFieldInitialization(CodeGenFunction &CGF,
587 CXXCtorInitializer *MemberInit,
589 FieldDecl *Field = MemberInit->getAnyMember();
590 if (MemberInit->isIndirectMemberInitializer()) {
591 // If we are initializing an anonymous union field, drill down to the field.
592 IndirectFieldDecl *IndirectField = MemberInit->getIndirectMember();
593 for (const auto *I : IndirectField->chain())
594 LHS = CGF.EmitLValueForFieldInitialization(LHS, cast<FieldDecl>(I));
596 LHS = CGF.EmitLValueForFieldInitialization(LHS, Field);
600 static void EmitMemberInitializer(CodeGenFunction &CGF,
601 const CXXRecordDecl *ClassDecl,
602 CXXCtorInitializer *MemberInit,
603 const CXXConstructorDecl *Constructor,
604 FunctionArgList &Args) {
605 ApplyDebugLocation Loc(CGF, MemberInit->getSourceLocation());
606 assert(MemberInit->isAnyMemberInitializer() &&
607 "Must have member initializer!");
608 assert(MemberInit->getInit() && "Must have initializer!");
610 // non-static data member initializers.
611 FieldDecl *Field = MemberInit->getAnyMember();
612 QualType FieldType = Field->getType();
614 llvm::Value *ThisPtr = CGF.LoadCXXThis();
615 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
616 LValue LHS = CGF.MakeNaturalAlignAddrLValue(ThisPtr, RecordTy);
618 EmitLValueForAnyFieldInitialization(CGF, MemberInit, LHS);
620 // Special case: if we are in a copy or move constructor, and we are copying
621 // an array of PODs or classes with trivial copy constructors, ignore the
622 // AST and perform the copy we know is equivalent.
623 // FIXME: This is hacky at best... if we had a bit more explicit information
624 // in the AST, we could generalize it more easily.
625 const ConstantArrayType *Array
626 = CGF.getContext().getAsConstantArrayType(FieldType);
627 if (Array && Constructor->isDefaulted() &&
628 Constructor->isCopyOrMoveConstructor()) {
629 QualType BaseElementTy = CGF.getContext().getBaseElementType(Array);
630 CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit());
631 if (BaseElementTy.isPODType(CGF.getContext()) ||
632 (CE && isMemcpyEquivalentSpecialMember(CE->getConstructor()))) {
633 unsigned SrcArgIndex =
634 CGF.CGM.getCXXABI().getSrcArgforCopyCtor(Constructor, Args);
636 = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(Args[SrcArgIndex]));
637 LValue ThisRHSLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy);
638 LValue Src = CGF.EmitLValueForFieldInitialization(ThisRHSLV, Field);
640 // Copy the aggregate.
641 CGF.EmitAggregateCopy(LHS.getAddress(), Src.getAddress(), FieldType,
642 LHS.isVolatileQualified());
643 // Ensure that we destroy the objects if an exception is thrown later in
645 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
646 if (CGF.needsEHCleanup(dtorKind))
647 CGF.pushEHDestroy(dtorKind, LHS.getAddress(), FieldType);
652 CGF.EmitInitializerForField(Field, LHS, MemberInit->getInit());
655 void CodeGenFunction::EmitInitializerForField(FieldDecl *Field, LValue LHS,
657 QualType FieldType = Field->getType();
658 switch (getEvaluationKind(FieldType)) {
660 if (LHS.isSimple()) {
661 EmitExprAsInit(Init, Field, LHS, false);
663 RValue RHS = RValue::get(EmitScalarExpr(Init));
664 EmitStoreThroughLValue(RHS, LHS);
668 EmitComplexExprIntoLValue(Init, LHS, /*isInit*/ true);
670 case TEK_Aggregate: {
672 AggValueSlot::forLValue(LHS,
673 AggValueSlot::IsDestructed,
674 AggValueSlot::DoesNotNeedGCBarriers,
675 AggValueSlot::IsNotAliased);
676 EmitAggExpr(Init, Slot);
681 // Ensure that we destroy this object if an exception is thrown
682 // later in the constructor.
683 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
684 if (needsEHCleanup(dtorKind))
685 pushEHDestroy(dtorKind, LHS.getAddress(), FieldType);
688 /// Checks whether the given constructor is a valid subject for the
689 /// complete-to-base constructor delegation optimization, i.e.
690 /// emitting the complete constructor as a simple call to the base
692 bool CodeGenFunction::IsConstructorDelegationValid(
693 const CXXConstructorDecl *Ctor) {
695 // Currently we disable the optimization for classes with virtual
696 // bases because (1) the addresses of parameter variables need to be
697 // consistent across all initializers but (2) the delegate function
698 // call necessarily creates a second copy of the parameter variable.
700 // The limiting example (purely theoretical AFAIK):
701 // struct A { A(int &c) { c++; } };
702 // struct B : virtual A {
703 // B(int count) : A(count) { printf("%d\n", count); }
705 // ...although even this example could in principle be emitted as a
706 // delegation since the address of the parameter doesn't escape.
707 if (Ctor->getParent()->getNumVBases()) {
708 // TODO: white-list trivial vbase initializers. This case wouldn't
709 // be subject to the restrictions below.
711 // TODO: white-list cases where:
712 // - there are no non-reference parameters to the constructor
713 // - the initializers don't access any non-reference parameters
714 // - the initializers don't take the address of non-reference
717 // If we ever add any of the above cases, remember that:
718 // - function-try-blocks will always blacklist this optimization
719 // - we need to perform the constructor prologue and cleanup in
720 // EmitConstructorBody.
725 // We also disable the optimization for variadic functions because
726 // it's impossible to "re-pass" varargs.
727 if (Ctor->getType()->getAs<FunctionProtoType>()->isVariadic())
730 // FIXME: Decide if we can do a delegation of a delegating constructor.
731 if (Ctor->isDelegatingConstructor())
737 // Emit code in ctor (Prologue==true) or dtor (Prologue==false)
738 // to poison the extra field paddings inserted under
739 // -fsanitize-address-field-padding=1|2.
740 void CodeGenFunction::EmitAsanPrologueOrEpilogue(bool Prologue) {
741 ASTContext &Context = getContext();
742 const CXXRecordDecl *ClassDecl =
743 Prologue ? cast<CXXConstructorDecl>(CurGD.getDecl())->getParent()
744 : cast<CXXDestructorDecl>(CurGD.getDecl())->getParent();
745 if (!ClassDecl->mayInsertExtraPadding()) return;
747 struct SizeAndOffset {
752 unsigned PtrSize = CGM.getDataLayout().getPointerSizeInBits();
753 const ASTRecordLayout &Info = Context.getASTRecordLayout(ClassDecl);
755 // Populate sizes and offsets of fields.
756 SmallVector<SizeAndOffset, 16> SSV(Info.getFieldCount());
757 for (unsigned i = 0, e = Info.getFieldCount(); i != e; ++i)
759 Context.toCharUnitsFromBits(Info.getFieldOffset(i)).getQuantity();
761 size_t NumFields = 0;
762 for (const auto *Field : ClassDecl->fields()) {
763 const FieldDecl *D = Field;
764 std::pair<CharUnits, CharUnits> FieldInfo =
765 Context.getTypeInfoInChars(D->getType());
766 CharUnits FieldSize = FieldInfo.first;
767 assert(NumFields < SSV.size());
768 SSV[NumFields].Size = D->isBitField() ? 0 : FieldSize.getQuantity();
771 assert(NumFields == SSV.size());
772 if (SSV.size() <= 1) return;
774 // We will insert calls to __asan_* run-time functions.
775 // LLVM AddressSanitizer pass may decide to inline them later.
776 llvm::Type *Args[2] = {IntPtrTy, IntPtrTy};
777 llvm::FunctionType *FTy =
778 llvm::FunctionType::get(CGM.VoidTy, Args, false);
779 llvm::Constant *F = CGM.CreateRuntimeFunction(
780 FTy, Prologue ? "__asan_poison_intra_object_redzone"
781 : "__asan_unpoison_intra_object_redzone");
783 llvm::Value *ThisPtr = LoadCXXThis();
784 ThisPtr = Builder.CreatePtrToInt(ThisPtr, IntPtrTy);
785 uint64_t TypeSize = Info.getNonVirtualSize().getQuantity();
786 // For each field check if it has sufficient padding,
787 // if so (un)poison it with a call.
788 for (size_t i = 0; i < SSV.size(); i++) {
789 uint64_t AsanAlignment = 8;
790 uint64_t NextField = i == SSV.size() - 1 ? TypeSize : SSV[i + 1].Offset;
791 uint64_t PoisonSize = NextField - SSV[i].Offset - SSV[i].Size;
792 uint64_t EndOffset = SSV[i].Offset + SSV[i].Size;
793 if (PoisonSize < AsanAlignment || !SSV[i].Size ||
794 (NextField % AsanAlignment) != 0)
797 F, {Builder.CreateAdd(ThisPtr, Builder.getIntN(PtrSize, EndOffset)),
798 Builder.getIntN(PtrSize, PoisonSize)});
802 /// EmitConstructorBody - Emits the body of the current constructor.
803 void CodeGenFunction::EmitConstructorBody(FunctionArgList &Args) {
804 EmitAsanPrologueOrEpilogue(true);
805 const CXXConstructorDecl *Ctor = cast<CXXConstructorDecl>(CurGD.getDecl());
806 CXXCtorType CtorType = CurGD.getCtorType();
808 assert((CGM.getTarget().getCXXABI().hasConstructorVariants() ||
809 CtorType == Ctor_Complete) &&
810 "can only generate complete ctor for this ABI");
812 // Before we go any further, try the complete->base constructor
813 // delegation optimization.
814 if (CtorType == Ctor_Complete && IsConstructorDelegationValid(Ctor) &&
815 CGM.getTarget().getCXXABI().hasConstructorVariants()) {
816 EmitDelegateCXXConstructorCall(Ctor, Ctor_Base, Args, Ctor->getLocEnd());
820 const FunctionDecl *Definition = nullptr;
821 Stmt *Body = Ctor->getBody(Definition);
822 assert(Definition == Ctor && "emitting wrong constructor body");
824 // Enter the function-try-block before the constructor prologue if
826 bool IsTryBody = (Body && isa<CXXTryStmt>(Body));
828 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
830 incrementProfileCounter(Body);
832 RunCleanupsScope RunCleanups(*this);
834 // TODO: in restricted cases, we can emit the vbase initializers of
835 // a complete ctor and then delegate to the base ctor.
837 // Emit the constructor prologue, i.e. the base and member
839 EmitCtorPrologue(Ctor, CtorType, Args);
841 // Emit the body of the statement.
843 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
847 // Emit any cleanup blocks associated with the member or base
848 // initializers, which includes (along the exceptional path) the
849 // destructors for those members and bases that were fully
851 RunCleanups.ForceCleanup();
854 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
858 /// RAII object to indicate that codegen is copying the value representation
859 /// instead of the object representation. Useful when copying a struct or
860 /// class which has uninitialized members and we're only performing
861 /// lvalue-to-rvalue conversion on the object but not its members.
862 class CopyingValueRepresentation {
864 explicit CopyingValueRepresentation(CodeGenFunction &CGF)
865 : CGF(CGF), OldSanOpts(CGF.SanOpts) {
866 CGF.SanOpts.set(SanitizerKind::Bool, false);
867 CGF.SanOpts.set(SanitizerKind::Enum, false);
869 ~CopyingValueRepresentation() {
870 CGF.SanOpts = OldSanOpts;
873 CodeGenFunction &CGF;
874 SanitizerSet OldSanOpts;
876 } // end anonymous namespace
879 class FieldMemcpyizer {
881 FieldMemcpyizer(CodeGenFunction &CGF, const CXXRecordDecl *ClassDecl,
882 const VarDecl *SrcRec)
883 : CGF(CGF), ClassDecl(ClassDecl), SrcRec(SrcRec),
884 RecLayout(CGF.getContext().getASTRecordLayout(ClassDecl)),
885 FirstField(nullptr), LastField(nullptr), FirstFieldOffset(0),
886 LastFieldOffset(0), LastAddedFieldIndex(0) {}
888 bool isMemcpyableField(FieldDecl *F) const {
889 // Never memcpy fields when we are adding poisoned paddings.
890 if (CGF.getContext().getLangOpts().SanitizeAddressFieldPadding)
892 Qualifiers Qual = F->getType().getQualifiers();
893 if (Qual.hasVolatile() || Qual.hasObjCLifetime())
898 void addMemcpyableField(FieldDecl *F) {
905 CharUnits getMemcpySize(uint64_t FirstByteOffset) const {
906 unsigned LastFieldSize =
907 LastField->isBitField() ?
908 LastField->getBitWidthValue(CGF.getContext()) :
909 CGF.getContext().getTypeSize(LastField->getType());
910 uint64_t MemcpySizeBits =
911 LastFieldOffset + LastFieldSize - FirstByteOffset +
912 CGF.getContext().getCharWidth() - 1;
913 CharUnits MemcpySize =
914 CGF.getContext().toCharUnitsFromBits(MemcpySizeBits);
919 // Give the subclass a chance to bail out if it feels the memcpy isn't
920 // worth it (e.g. Hasn't aggregated enough data).
925 uint64_t FirstByteOffset;
926 if (FirstField->isBitField()) {
927 const CGRecordLayout &RL =
928 CGF.getTypes().getCGRecordLayout(FirstField->getParent());
929 const CGBitFieldInfo &BFInfo = RL.getBitFieldInfo(FirstField);
930 // FirstFieldOffset is not appropriate for bitfields,
931 // we need to use the storage offset instead.
932 FirstByteOffset = CGF.getContext().toBits(BFInfo.StorageOffset);
934 FirstByteOffset = FirstFieldOffset;
937 CharUnits MemcpySize = getMemcpySize(FirstByteOffset);
938 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
939 Address ThisPtr = CGF.LoadCXXThisAddress();
940 LValue DestLV = CGF.MakeAddrLValue(ThisPtr, RecordTy);
941 LValue Dest = CGF.EmitLValueForFieldInitialization(DestLV, FirstField);
942 llvm::Value *SrcPtr = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(SrcRec));
943 LValue SrcLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy);
944 LValue Src = CGF.EmitLValueForFieldInitialization(SrcLV, FirstField);
946 emitMemcpyIR(Dest.isBitField() ? Dest.getBitFieldAddress() : Dest.getAddress(),
947 Src.isBitField() ? Src.getBitFieldAddress() : Src.getAddress(),
953 FirstField = nullptr;
957 CodeGenFunction &CGF;
958 const CXXRecordDecl *ClassDecl;
961 void emitMemcpyIR(Address DestPtr, Address SrcPtr, CharUnits Size) {
962 llvm::PointerType *DPT = DestPtr.getType();
964 llvm::Type::getInt8PtrTy(CGF.getLLVMContext(), DPT->getAddressSpace());
965 DestPtr = CGF.Builder.CreateBitCast(DestPtr, DBP);
967 llvm::PointerType *SPT = SrcPtr.getType();
969 llvm::Type::getInt8PtrTy(CGF.getLLVMContext(), SPT->getAddressSpace());
970 SrcPtr = CGF.Builder.CreateBitCast(SrcPtr, SBP);
972 CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, Size.getQuantity());
975 void addInitialField(FieldDecl *F) {
978 FirstFieldOffset = RecLayout.getFieldOffset(F->getFieldIndex());
979 LastFieldOffset = FirstFieldOffset;
980 LastAddedFieldIndex = F->getFieldIndex();
983 void addNextField(FieldDecl *F) {
984 // For the most part, the following invariant will hold:
985 // F->getFieldIndex() == LastAddedFieldIndex + 1
986 // The one exception is that Sema won't add a copy-initializer for an
987 // unnamed bitfield, which will show up here as a gap in the sequence.
988 assert(F->getFieldIndex() >= LastAddedFieldIndex + 1 &&
989 "Cannot aggregate fields out of order.");
990 LastAddedFieldIndex = F->getFieldIndex();
992 // The 'first' and 'last' fields are chosen by offset, rather than field
993 // index. This allows the code to support bitfields, as well as regular
995 uint64_t FOffset = RecLayout.getFieldOffset(F->getFieldIndex());
996 if (FOffset < FirstFieldOffset) {
998 FirstFieldOffset = FOffset;
999 } else if (FOffset > LastFieldOffset) {
1001 LastFieldOffset = FOffset;
1005 const VarDecl *SrcRec;
1006 const ASTRecordLayout &RecLayout;
1007 FieldDecl *FirstField;
1008 FieldDecl *LastField;
1009 uint64_t FirstFieldOffset, LastFieldOffset;
1010 unsigned LastAddedFieldIndex;
1013 class ConstructorMemcpyizer : public FieldMemcpyizer {
1015 /// Get source argument for copy constructor. Returns null if not a copy
1017 static const VarDecl *getTrivialCopySource(CodeGenFunction &CGF,
1018 const CXXConstructorDecl *CD,
1019 FunctionArgList &Args) {
1020 if (CD->isCopyOrMoveConstructor() && CD->isDefaulted())
1021 return Args[CGF.CGM.getCXXABI().getSrcArgforCopyCtor(CD, Args)];
1025 // Returns true if a CXXCtorInitializer represents a member initialization
1026 // that can be rolled into a memcpy.
1027 bool isMemberInitMemcpyable(CXXCtorInitializer *MemberInit) const {
1028 if (!MemcpyableCtor)
1030 FieldDecl *Field = MemberInit->getMember();
1031 assert(Field && "No field for member init.");
1032 QualType FieldType = Field->getType();
1033 CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit());
1035 // Bail out on non-memcpyable, not-trivially-copyable members.
1036 if (!(CE && isMemcpyEquivalentSpecialMember(CE->getConstructor())) &&
1037 !(FieldType.isTriviallyCopyableType(CGF.getContext()) ||
1038 FieldType->isReferenceType()))
1041 // Bail out on volatile fields.
1042 if (!isMemcpyableField(Field))
1045 // Otherwise we're good.
1050 ConstructorMemcpyizer(CodeGenFunction &CGF, const CXXConstructorDecl *CD,
1051 FunctionArgList &Args)
1052 : FieldMemcpyizer(CGF, CD->getParent(), getTrivialCopySource(CGF, CD, Args)),
1053 ConstructorDecl(CD),
1054 MemcpyableCtor(CD->isDefaulted() &&
1055 CD->isCopyOrMoveConstructor() &&
1056 CGF.getLangOpts().getGC() == LangOptions::NonGC),
1059 void addMemberInitializer(CXXCtorInitializer *MemberInit) {
1060 if (isMemberInitMemcpyable(MemberInit)) {
1061 AggregatedInits.push_back(MemberInit);
1062 addMemcpyableField(MemberInit->getMember());
1064 emitAggregatedInits();
1065 EmitMemberInitializer(CGF, ConstructorDecl->getParent(), MemberInit,
1066 ConstructorDecl, Args);
1070 void emitAggregatedInits() {
1071 if (AggregatedInits.size() <= 1) {
1072 // This memcpy is too small to be worthwhile. Fall back on default
1074 if (!AggregatedInits.empty()) {
1075 CopyingValueRepresentation CVR(CGF);
1076 EmitMemberInitializer(CGF, ConstructorDecl->getParent(),
1077 AggregatedInits[0], ConstructorDecl, Args);
1078 AggregatedInits.clear();
1084 pushEHDestructors();
1086 AggregatedInits.clear();
1089 void pushEHDestructors() {
1090 Address ThisPtr = CGF.LoadCXXThisAddress();
1091 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
1092 LValue LHS = CGF.MakeAddrLValue(ThisPtr, RecordTy);
1094 for (unsigned i = 0; i < AggregatedInits.size(); ++i) {
1095 CXXCtorInitializer *MemberInit = AggregatedInits[i];
1096 QualType FieldType = MemberInit->getAnyMember()->getType();
1097 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
1098 if (!CGF.needsEHCleanup(dtorKind))
1100 LValue FieldLHS = LHS;
1101 EmitLValueForAnyFieldInitialization(CGF, MemberInit, FieldLHS);
1102 CGF.pushEHDestroy(dtorKind, FieldLHS.getAddress(), FieldType);
1107 emitAggregatedInits();
1111 const CXXConstructorDecl *ConstructorDecl;
1112 bool MemcpyableCtor;
1113 FunctionArgList &Args;
1114 SmallVector<CXXCtorInitializer*, 16> AggregatedInits;
1117 class AssignmentMemcpyizer : public FieldMemcpyizer {
1119 // Returns the memcpyable field copied by the given statement, if one
1120 // exists. Otherwise returns null.
1121 FieldDecl *getMemcpyableField(Stmt *S) {
1122 if (!AssignmentsMemcpyable)
1124 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(S)) {
1125 // Recognise trivial assignments.
1126 if (BO->getOpcode() != BO_Assign)
1128 MemberExpr *ME = dyn_cast<MemberExpr>(BO->getLHS());
1131 FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl());
1132 if (!Field || !isMemcpyableField(Field))
1134 Stmt *RHS = BO->getRHS();
1135 if (ImplicitCastExpr *EC = dyn_cast<ImplicitCastExpr>(RHS))
1136 RHS = EC->getSubExpr();
1139 if (MemberExpr *ME2 = dyn_cast<MemberExpr>(RHS)) {
1140 if (ME2->getMemberDecl() == Field)
1144 } else if (CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(S)) {
1145 CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MCE->getCalleeDecl());
1146 if (!(MD && isMemcpyEquivalentSpecialMember(MD)))
1148 MemberExpr *IOA = dyn_cast<MemberExpr>(MCE->getImplicitObjectArgument());
1151 FieldDecl *Field = dyn_cast<FieldDecl>(IOA->getMemberDecl());
1152 if (!Field || !isMemcpyableField(Field))
1154 MemberExpr *Arg0 = dyn_cast<MemberExpr>(MCE->getArg(0));
1155 if (!Arg0 || Field != dyn_cast<FieldDecl>(Arg0->getMemberDecl()))
1158 } else if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
1159 FunctionDecl *FD = dyn_cast<FunctionDecl>(CE->getCalleeDecl());
1160 if (!FD || FD->getBuiltinID() != Builtin::BI__builtin_memcpy)
1162 Expr *DstPtr = CE->getArg(0);
1163 if (ImplicitCastExpr *DC = dyn_cast<ImplicitCastExpr>(DstPtr))
1164 DstPtr = DC->getSubExpr();
1165 UnaryOperator *DUO = dyn_cast<UnaryOperator>(DstPtr);
1166 if (!DUO || DUO->getOpcode() != UO_AddrOf)
1168 MemberExpr *ME = dyn_cast<MemberExpr>(DUO->getSubExpr());
1171 FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl());
1172 if (!Field || !isMemcpyableField(Field))
1174 Expr *SrcPtr = CE->getArg(1);
1175 if (ImplicitCastExpr *SC = dyn_cast<ImplicitCastExpr>(SrcPtr))
1176 SrcPtr = SC->getSubExpr();
1177 UnaryOperator *SUO = dyn_cast<UnaryOperator>(SrcPtr);
1178 if (!SUO || SUO->getOpcode() != UO_AddrOf)
1180 MemberExpr *ME2 = dyn_cast<MemberExpr>(SUO->getSubExpr());
1181 if (!ME2 || Field != dyn_cast<FieldDecl>(ME2->getMemberDecl()))
1189 bool AssignmentsMemcpyable;
1190 SmallVector<Stmt*, 16> AggregatedStmts;
1193 AssignmentMemcpyizer(CodeGenFunction &CGF, const CXXMethodDecl *AD,
1194 FunctionArgList &Args)
1195 : FieldMemcpyizer(CGF, AD->getParent(), Args[Args.size() - 1]),
1196 AssignmentsMemcpyable(CGF.getLangOpts().getGC() == LangOptions::NonGC) {
1197 assert(Args.size() == 2);
1200 void emitAssignment(Stmt *S) {
1201 FieldDecl *F = getMemcpyableField(S);
1203 addMemcpyableField(F);
1204 AggregatedStmts.push_back(S);
1206 emitAggregatedStmts();
1211 void emitAggregatedStmts() {
1212 if (AggregatedStmts.size() <= 1) {
1213 if (!AggregatedStmts.empty()) {
1214 CopyingValueRepresentation CVR(CGF);
1215 CGF.EmitStmt(AggregatedStmts[0]);
1221 AggregatedStmts.clear();
1225 emitAggregatedStmts();
1228 } // end anonymous namespace
1230 static bool isInitializerOfDynamicClass(const CXXCtorInitializer *BaseInit) {
1231 const Type *BaseType = BaseInit->getBaseClass();
1232 const auto *BaseClassDecl =
1233 cast<CXXRecordDecl>(BaseType->getAs<RecordType>()->getDecl());
1234 return BaseClassDecl->isDynamicClass();
1237 /// EmitCtorPrologue - This routine generates necessary code to initialize
1238 /// base classes and non-static data members belonging to this constructor.
1239 void CodeGenFunction::EmitCtorPrologue(const CXXConstructorDecl *CD,
1240 CXXCtorType CtorType,
1241 FunctionArgList &Args) {
1242 if (CD->isDelegatingConstructor())
1243 return EmitDelegatingCXXConstructorCall(CD, Args);
1245 const CXXRecordDecl *ClassDecl = CD->getParent();
1247 CXXConstructorDecl::init_const_iterator B = CD->init_begin(),
1250 llvm::BasicBlock *BaseCtorContinueBB = nullptr;
1251 if (ClassDecl->getNumVBases() &&
1252 !CGM.getTarget().getCXXABI().hasConstructorVariants()) {
1253 // The ABIs that don't have constructor variants need to put a branch
1254 // before the virtual base initialization code.
1255 BaseCtorContinueBB =
1256 CGM.getCXXABI().EmitCtorCompleteObjectHandler(*this, ClassDecl);
1257 assert(BaseCtorContinueBB);
1260 llvm::Value *const OldThis = CXXThisValue;
1261 // Virtual base initializers first.
1262 for (; B != E && (*B)->isBaseInitializer() && (*B)->isBaseVirtual(); B++) {
1263 if (CGM.getCodeGenOpts().StrictVTablePointers &&
1264 CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1265 isInitializerOfDynamicClass(*B))
1266 CXXThisValue = Builder.CreateInvariantGroupBarrier(LoadCXXThis());
1267 EmitBaseInitializer(*this, ClassDecl, *B, CtorType);
1270 if (BaseCtorContinueBB) {
1271 // Complete object handler should continue to the remaining initializers.
1272 Builder.CreateBr(BaseCtorContinueBB);
1273 EmitBlock(BaseCtorContinueBB);
1276 // Then, non-virtual base initializers.
1277 for (; B != E && (*B)->isBaseInitializer(); B++) {
1278 assert(!(*B)->isBaseVirtual());
1280 if (CGM.getCodeGenOpts().StrictVTablePointers &&
1281 CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1282 isInitializerOfDynamicClass(*B))
1283 CXXThisValue = Builder.CreateInvariantGroupBarrier(LoadCXXThis());
1284 EmitBaseInitializer(*this, ClassDecl, *B, CtorType);
1287 CXXThisValue = OldThis;
1289 InitializeVTablePointers(ClassDecl);
1291 // And finally, initialize class members.
1292 FieldConstructionScope FCS(*this, LoadCXXThisAddress());
1293 ConstructorMemcpyizer CM(*this, CD, Args);
1294 for (; B != E; B++) {
1295 CXXCtorInitializer *Member = (*B);
1296 assert(!Member->isBaseInitializer());
1297 assert(Member->isAnyMemberInitializer() &&
1298 "Delegating initializer on non-delegating constructor");
1299 CM.addMemberInitializer(Member);
1305 FieldHasTrivialDestructorBody(ASTContext &Context, const FieldDecl *Field);
1308 HasTrivialDestructorBody(ASTContext &Context,
1309 const CXXRecordDecl *BaseClassDecl,
1310 const CXXRecordDecl *MostDerivedClassDecl)
1312 // If the destructor is trivial we don't have to check anything else.
1313 if (BaseClassDecl->hasTrivialDestructor())
1316 if (!BaseClassDecl->getDestructor()->hasTrivialBody())
1320 for (const auto *Field : BaseClassDecl->fields())
1321 if (!FieldHasTrivialDestructorBody(Context, Field))
1324 // Check non-virtual bases.
1325 for (const auto &I : BaseClassDecl->bases()) {
1329 const CXXRecordDecl *NonVirtualBase =
1330 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
1331 if (!HasTrivialDestructorBody(Context, NonVirtualBase,
1332 MostDerivedClassDecl))
1336 if (BaseClassDecl == MostDerivedClassDecl) {
1337 // Check virtual bases.
1338 for (const auto &I : BaseClassDecl->vbases()) {
1339 const CXXRecordDecl *VirtualBase =
1340 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
1341 if (!HasTrivialDestructorBody(Context, VirtualBase,
1342 MostDerivedClassDecl))
1351 FieldHasTrivialDestructorBody(ASTContext &Context,
1352 const FieldDecl *Field)
1354 QualType FieldBaseElementType = Context.getBaseElementType(Field->getType());
1356 const RecordType *RT = FieldBaseElementType->getAs<RecordType>();
1360 CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
1362 // The destructor for an implicit anonymous union member is never invoked.
1363 if (FieldClassDecl->isUnion() && FieldClassDecl->isAnonymousStructOrUnion())
1366 return HasTrivialDestructorBody(Context, FieldClassDecl, FieldClassDecl);
1369 /// CanSkipVTablePointerInitialization - Check whether we need to initialize
1370 /// any vtable pointers before calling this destructor.
1371 static bool CanSkipVTablePointerInitialization(CodeGenFunction &CGF,
1372 const CXXDestructorDecl *Dtor) {
1373 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1374 if (!ClassDecl->isDynamicClass())
1377 if (!Dtor->hasTrivialBody())
1380 // Check the fields.
1381 for (const auto *Field : ClassDecl->fields())
1382 if (!FieldHasTrivialDestructorBody(CGF.getContext(), Field))
1388 /// EmitDestructorBody - Emits the body of the current destructor.
1389 void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) {
1390 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CurGD.getDecl());
1391 CXXDtorType DtorType = CurGD.getDtorType();
1393 // For an abstract class, non-base destructors are never used (and can't
1394 // be emitted in general, because vbase dtors may not have been validated
1395 // by Sema), but the Itanium ABI doesn't make them optional and Clang may
1396 // in fact emit references to them from other compilations, so emit them
1397 // as functions containing a trap instruction.
1398 if (DtorType != Dtor_Base && Dtor->getParent()->isAbstract()) {
1399 llvm::CallInst *TrapCall = EmitTrapCall(llvm::Intrinsic::trap);
1400 TrapCall->setDoesNotReturn();
1401 TrapCall->setDoesNotThrow();
1402 Builder.CreateUnreachable();
1403 Builder.ClearInsertionPoint();
1407 Stmt *Body = Dtor->getBody();
1409 incrementProfileCounter(Body);
1411 // The call to operator delete in a deleting destructor happens
1412 // outside of the function-try-block, which means it's always
1413 // possible to delegate the destructor body to the complete
1414 // destructor. Do so.
1415 if (DtorType == Dtor_Deleting) {
1416 EnterDtorCleanups(Dtor, Dtor_Deleting);
1417 EmitCXXDestructorCall(Dtor, Dtor_Complete, /*ForVirtualBase=*/false,
1418 /*Delegating=*/false, LoadCXXThisAddress());
1423 // If the body is a function-try-block, enter the try before
1425 bool isTryBody = (Body && isa<CXXTryStmt>(Body));
1427 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
1428 EmitAsanPrologueOrEpilogue(false);
1430 // Enter the epilogue cleanups.
1431 RunCleanupsScope DtorEpilogue(*this);
1433 // If this is the complete variant, just invoke the base variant;
1434 // the epilogue will destruct the virtual bases. But we can't do
1435 // this optimization if the body is a function-try-block, because
1436 // we'd introduce *two* handler blocks. In the Microsoft ABI, we
1437 // always delegate because we might not have a definition in this TU.
1439 case Dtor_Comdat: llvm_unreachable("not expecting a COMDAT");
1440 case Dtor_Deleting: llvm_unreachable("already handled deleting case");
1443 assert((Body || getTarget().getCXXABI().isMicrosoft()) &&
1444 "can't emit a dtor without a body for non-Microsoft ABIs");
1446 // Enter the cleanup scopes for virtual bases.
1447 EnterDtorCleanups(Dtor, Dtor_Complete);
1450 EmitCXXDestructorCall(Dtor, Dtor_Base, /*ForVirtualBase=*/false,
1451 /*Delegating=*/false, LoadCXXThisAddress());
1455 // Fallthrough: act like we're in the base variant.
1461 // Enter the cleanup scopes for fields and non-virtual bases.
1462 EnterDtorCleanups(Dtor, Dtor_Base);
1464 // Initialize the vtable pointers before entering the body.
1465 if (!CanSkipVTablePointerInitialization(*this, Dtor)) {
1466 // Insert the llvm.invariant.group.barrier intrinsic before initializing
1467 // the vptrs to cancel any previous assumptions we might have made.
1468 if (CGM.getCodeGenOpts().StrictVTablePointers &&
1469 CGM.getCodeGenOpts().OptimizationLevel > 0)
1470 CXXThisValue = Builder.CreateInvariantGroupBarrier(LoadCXXThis());
1471 InitializeVTablePointers(Dtor->getParent());
1475 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
1479 assert(Dtor->isImplicit() && "bodyless dtor not implicit");
1480 // nothing to do besides what's in the epilogue
1482 // -fapple-kext must inline any call to this dtor into
1483 // the caller's body.
1484 if (getLangOpts().AppleKext)
1485 CurFn->addFnAttr(llvm::Attribute::AlwaysInline);
1490 // Jump out through the epilogue cleanups.
1491 DtorEpilogue.ForceCleanup();
1493 // Exit the try if applicable.
1495 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
1498 void CodeGenFunction::emitImplicitAssignmentOperatorBody(FunctionArgList &Args) {
1499 const CXXMethodDecl *AssignOp = cast<CXXMethodDecl>(CurGD.getDecl());
1500 const Stmt *RootS = AssignOp->getBody();
1501 assert(isa<CompoundStmt>(RootS) &&
1502 "Body of an implicit assignment operator should be compound stmt.");
1503 const CompoundStmt *RootCS = cast<CompoundStmt>(RootS);
1505 LexicalScope Scope(*this, RootCS->getSourceRange());
1507 incrementProfileCounter(RootCS);
1508 AssignmentMemcpyizer AM(*this, AssignOp, Args);
1509 for (auto *I : RootCS->body())
1510 AM.emitAssignment(I);
1515 /// Call the operator delete associated with the current destructor.
1516 struct CallDtorDelete final : EHScopeStack::Cleanup {
1519 void Emit(CodeGenFunction &CGF, Flags flags) override {
1520 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
1521 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1522 CGF.EmitDeleteCall(Dtor->getOperatorDelete(), CGF.LoadCXXThis(),
1523 CGF.getContext().getTagDeclType(ClassDecl));
1527 struct CallDtorDeleteConditional final : EHScopeStack::Cleanup {
1528 llvm::Value *ShouldDeleteCondition;
1531 CallDtorDeleteConditional(llvm::Value *ShouldDeleteCondition)
1532 : ShouldDeleteCondition(ShouldDeleteCondition) {
1533 assert(ShouldDeleteCondition != nullptr);
1536 void Emit(CodeGenFunction &CGF, Flags flags) override {
1537 llvm::BasicBlock *callDeleteBB = CGF.createBasicBlock("dtor.call_delete");
1538 llvm::BasicBlock *continueBB = CGF.createBasicBlock("dtor.continue");
1539 llvm::Value *ShouldCallDelete
1540 = CGF.Builder.CreateIsNull(ShouldDeleteCondition);
1541 CGF.Builder.CreateCondBr(ShouldCallDelete, continueBB, callDeleteBB);
1543 CGF.EmitBlock(callDeleteBB);
1544 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
1545 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1546 CGF.EmitDeleteCall(Dtor->getOperatorDelete(), CGF.LoadCXXThis(),
1547 CGF.getContext().getTagDeclType(ClassDecl));
1548 CGF.Builder.CreateBr(continueBB);
1550 CGF.EmitBlock(continueBB);
1554 class DestroyField final : public EHScopeStack::Cleanup {
1555 const FieldDecl *field;
1556 CodeGenFunction::Destroyer *destroyer;
1557 bool useEHCleanupForArray;
1560 DestroyField(const FieldDecl *field, CodeGenFunction::Destroyer *destroyer,
1561 bool useEHCleanupForArray)
1562 : field(field), destroyer(destroyer),
1563 useEHCleanupForArray(useEHCleanupForArray) {}
1565 void Emit(CodeGenFunction &CGF, Flags flags) override {
1566 // Find the address of the field.
1567 Address thisValue = CGF.LoadCXXThisAddress();
1568 QualType RecordTy = CGF.getContext().getTagDeclType(field->getParent());
1569 LValue ThisLV = CGF.MakeAddrLValue(thisValue, RecordTy);
1570 LValue LV = CGF.EmitLValueForField(ThisLV, field);
1571 assert(LV.isSimple());
1573 CGF.emitDestroy(LV.getAddress(), field->getType(), destroyer,
1574 flags.isForNormalCleanup() && useEHCleanupForArray);
1578 static void EmitSanitizerDtorCallback(CodeGenFunction &CGF, llvm::Value *Ptr,
1579 CharUnits::QuantityType PoisonSize) {
1580 // Pass in void pointer and size of region as arguments to runtime
1582 llvm::Value *Args[] = {CGF.Builder.CreateBitCast(Ptr, CGF.VoidPtrTy),
1583 llvm::ConstantInt::get(CGF.SizeTy, PoisonSize)};
1585 llvm::Type *ArgTypes[] = {CGF.VoidPtrTy, CGF.SizeTy};
1587 llvm::FunctionType *FnType =
1588 llvm::FunctionType::get(CGF.VoidTy, ArgTypes, false);
1590 CGF.CGM.CreateRuntimeFunction(FnType, "__sanitizer_dtor_callback");
1591 CGF.EmitNounwindRuntimeCall(Fn, Args);
1594 class SanitizeDtorMembers final : public EHScopeStack::Cleanup {
1595 const CXXDestructorDecl *Dtor;
1598 SanitizeDtorMembers(const CXXDestructorDecl *Dtor) : Dtor(Dtor) {}
1600 // Generate function call for handling object poisoning.
1601 // Disables tail call elimination, to prevent the current stack frame
1602 // from disappearing from the stack trace.
1603 void Emit(CodeGenFunction &CGF, Flags flags) override {
1604 const ASTRecordLayout &Layout =
1605 CGF.getContext().getASTRecordLayout(Dtor->getParent());
1607 // Nothing to poison.
1608 if (Layout.getFieldCount() == 0)
1611 // Prevent the current stack frame from disappearing from the stack trace.
1612 CGF.CurFn->addFnAttr("disable-tail-calls", "true");
1614 // Construct pointer to region to begin poisoning, and calculate poison
1615 // size, so that only members declared in this class are poisoned.
1616 ASTContext &Context = CGF.getContext();
1617 unsigned fieldIndex = 0;
1618 int startIndex = -1;
1619 // RecordDecl::field_iterator Field;
1620 for (const FieldDecl *Field : Dtor->getParent()->fields()) {
1621 // Poison field if it is trivial
1622 if (FieldHasTrivialDestructorBody(Context, Field)) {
1623 // Start sanitizing at this field
1625 startIndex = fieldIndex;
1627 // Currently on the last field, and it must be poisoned with the
1629 if (fieldIndex == Layout.getFieldCount() - 1) {
1630 PoisonMembers(CGF, startIndex, Layout.getFieldCount());
1632 } else if (startIndex >= 0) {
1633 // No longer within a block of memory to poison, so poison the block
1634 PoisonMembers(CGF, startIndex, fieldIndex);
1635 // Re-set the start index
1643 /// \param layoutStartOffset index of the ASTRecordLayout field to
1644 /// start poisoning (inclusive)
1645 /// \param layoutEndOffset index of the ASTRecordLayout field to
1646 /// end poisoning (exclusive)
1647 void PoisonMembers(CodeGenFunction &CGF, unsigned layoutStartOffset,
1648 unsigned layoutEndOffset) {
1649 ASTContext &Context = CGF.getContext();
1650 const ASTRecordLayout &Layout =
1651 Context.getASTRecordLayout(Dtor->getParent());
1653 llvm::ConstantInt *OffsetSizePtr = llvm::ConstantInt::get(
1655 Context.toCharUnitsFromBits(Layout.getFieldOffset(layoutStartOffset))
1658 llvm::Value *OffsetPtr = CGF.Builder.CreateGEP(
1659 CGF.Builder.CreateBitCast(CGF.LoadCXXThis(), CGF.Int8PtrTy),
1662 CharUnits::QuantityType PoisonSize;
1663 if (layoutEndOffset >= Layout.getFieldCount()) {
1664 PoisonSize = Layout.getNonVirtualSize().getQuantity() -
1665 Context.toCharUnitsFromBits(
1666 Layout.getFieldOffset(layoutStartOffset))
1669 PoisonSize = Context.toCharUnitsFromBits(
1670 Layout.getFieldOffset(layoutEndOffset) -
1671 Layout.getFieldOffset(layoutStartOffset))
1675 if (PoisonSize == 0)
1678 EmitSanitizerDtorCallback(CGF, OffsetPtr, PoisonSize);
1682 class SanitizeDtorVTable final : public EHScopeStack::Cleanup {
1683 const CXXDestructorDecl *Dtor;
1686 SanitizeDtorVTable(const CXXDestructorDecl *Dtor) : Dtor(Dtor) {}
1688 // Generate function call for handling vtable pointer poisoning.
1689 void Emit(CodeGenFunction &CGF, Flags flags) override {
1690 assert(Dtor->getParent()->isDynamicClass());
1692 ASTContext &Context = CGF.getContext();
1693 // Poison vtable and vtable ptr if they exist for this class.
1694 llvm::Value *VTablePtr = CGF.LoadCXXThis();
1696 CharUnits::QuantityType PoisonSize =
1697 Context.toCharUnitsFromBits(CGF.PointerWidthInBits).getQuantity();
1698 // Pass in void pointer and size of region as arguments to runtime
1700 EmitSanitizerDtorCallback(CGF, VTablePtr, PoisonSize);
1703 } // end anonymous namespace
1705 /// \brief Emit all code that comes at the end of class's
1706 /// destructor. This is to call destructors on members and base classes
1707 /// in reverse order of their construction.
1708 void CodeGenFunction::EnterDtorCleanups(const CXXDestructorDecl *DD,
1709 CXXDtorType DtorType) {
1710 assert((!DD->isTrivial() || DD->hasAttr<DLLExportAttr>()) &&
1711 "Should not emit dtor epilogue for non-exported trivial dtor!");
1713 // The deleting-destructor phase just needs to call the appropriate
1714 // operator delete that Sema picked up.
1715 if (DtorType == Dtor_Deleting) {
1716 assert(DD->getOperatorDelete() &&
1717 "operator delete missing - EnterDtorCleanups");
1718 if (CXXStructorImplicitParamValue) {
1719 // If there is an implicit param to the deleting dtor, it's a boolean
1720 // telling whether we should call delete at the end of the dtor.
1721 EHStack.pushCleanup<CallDtorDeleteConditional>(
1722 NormalAndEHCleanup, CXXStructorImplicitParamValue);
1724 EHStack.pushCleanup<CallDtorDelete>(NormalAndEHCleanup);
1729 const CXXRecordDecl *ClassDecl = DD->getParent();
1731 // Unions have no bases and do not call field destructors.
1732 if (ClassDecl->isUnion())
1735 // The complete-destructor phase just destructs all the virtual bases.
1736 if (DtorType == Dtor_Complete) {
1737 // Poison the vtable pointer such that access after the base
1738 // and member destructors are invoked is invalid.
1739 if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor &&
1740 SanOpts.has(SanitizerKind::Memory) && ClassDecl->getNumVBases() &&
1741 ClassDecl->isPolymorphic())
1742 EHStack.pushCleanup<SanitizeDtorVTable>(NormalAndEHCleanup, DD);
1744 // We push them in the forward order so that they'll be popped in
1745 // the reverse order.
1746 for (const auto &Base : ClassDecl->vbases()) {
1747 CXXRecordDecl *BaseClassDecl
1748 = cast<CXXRecordDecl>(Base.getType()->getAs<RecordType>()->getDecl());
1750 // Ignore trivial destructors.
1751 if (BaseClassDecl->hasTrivialDestructor())
1754 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1756 /*BaseIsVirtual*/ true);
1762 assert(DtorType == Dtor_Base);
1763 // Poison the vtable pointer if it has no virtual bases, but inherits
1764 // virtual functions.
1765 if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor &&
1766 SanOpts.has(SanitizerKind::Memory) && !ClassDecl->getNumVBases() &&
1767 ClassDecl->isPolymorphic())
1768 EHStack.pushCleanup<SanitizeDtorVTable>(NormalAndEHCleanup, DD);
1770 // Destroy non-virtual bases.
1771 for (const auto &Base : ClassDecl->bases()) {
1772 // Ignore virtual bases.
1773 if (Base.isVirtual())
1776 CXXRecordDecl *BaseClassDecl = Base.getType()->getAsCXXRecordDecl();
1778 // Ignore trivial destructors.
1779 if (BaseClassDecl->hasTrivialDestructor())
1782 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1784 /*BaseIsVirtual*/ false);
1787 // Poison fields such that access after their destructors are
1788 // invoked, and before the base class destructor runs, is invalid.
1789 if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor &&
1790 SanOpts.has(SanitizerKind::Memory))
1791 EHStack.pushCleanup<SanitizeDtorMembers>(NormalAndEHCleanup, DD);
1793 // Destroy direct fields.
1794 for (const auto *Field : ClassDecl->fields()) {
1795 QualType type = Field->getType();
1796 QualType::DestructionKind dtorKind = type.isDestructedType();
1797 if (!dtorKind) continue;
1799 // Anonymous union members do not have their destructors called.
1800 const RecordType *RT = type->getAsUnionType();
1801 if (RT && RT->getDecl()->isAnonymousStructOrUnion()) continue;
1803 CleanupKind cleanupKind = getCleanupKind(dtorKind);
1804 EHStack.pushCleanup<DestroyField>(cleanupKind, Field,
1805 getDestroyer(dtorKind),
1806 cleanupKind & EHCleanup);
1810 /// EmitCXXAggrConstructorCall - Emit a loop to call a particular
1811 /// constructor for each of several members of an array.
1813 /// \param ctor the constructor to call for each element
1814 /// \param arrayType the type of the array to initialize
1815 /// \param arrayBegin an arrayType*
1816 /// \param zeroInitialize true if each element should be
1817 /// zero-initialized before it is constructed
1818 void CodeGenFunction::EmitCXXAggrConstructorCall(
1819 const CXXConstructorDecl *ctor, const ArrayType *arrayType,
1820 Address arrayBegin, const CXXConstructExpr *E, bool zeroInitialize) {
1821 QualType elementType;
1822 llvm::Value *numElements =
1823 emitArrayLength(arrayType, elementType, arrayBegin);
1825 EmitCXXAggrConstructorCall(ctor, numElements, arrayBegin, E, zeroInitialize);
1828 /// EmitCXXAggrConstructorCall - Emit a loop to call a particular
1829 /// constructor for each of several members of an array.
1831 /// \param ctor the constructor to call for each element
1832 /// \param numElements the number of elements in the array;
1834 /// \param arrayBase a T*, where T is the type constructed by ctor
1835 /// \param zeroInitialize true if each element should be
1836 /// zero-initialized before it is constructed
1837 void CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor,
1838 llvm::Value *numElements,
1840 const CXXConstructExpr *E,
1841 bool zeroInitialize) {
1842 // It's legal for numElements to be zero. This can happen both
1843 // dynamically, because x can be zero in 'new A[x]', and statically,
1844 // because of GCC extensions that permit zero-length arrays. There
1845 // are probably legitimate places where we could assume that this
1846 // doesn't happen, but it's not clear that it's worth it.
1847 llvm::BranchInst *zeroCheckBranch = nullptr;
1849 // Optimize for a constant count.
1850 llvm::ConstantInt *constantCount
1851 = dyn_cast<llvm::ConstantInt>(numElements);
1852 if (constantCount) {
1853 // Just skip out if the constant count is zero.
1854 if (constantCount->isZero()) return;
1856 // Otherwise, emit the check.
1858 llvm::BasicBlock *loopBB = createBasicBlock("new.ctorloop");
1859 llvm::Value *iszero = Builder.CreateIsNull(numElements, "isempty");
1860 zeroCheckBranch = Builder.CreateCondBr(iszero, loopBB, loopBB);
1864 // Find the end of the array.
1865 llvm::Value *arrayBegin = arrayBase.getPointer();
1866 llvm::Value *arrayEnd = Builder.CreateInBoundsGEP(arrayBegin, numElements,
1869 // Enter the loop, setting up a phi for the current location to initialize.
1870 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1871 llvm::BasicBlock *loopBB = createBasicBlock("arrayctor.loop");
1873 llvm::PHINode *cur = Builder.CreatePHI(arrayBegin->getType(), 2,
1875 cur->addIncoming(arrayBegin, entryBB);
1877 // Inside the loop body, emit the constructor call on the array element.
1879 // The alignment of the base, adjusted by the size of a single element,
1880 // provides a conservative estimate of the alignment of every element.
1881 // (This assumes we never start tracking offsetted alignments.)
1883 // Note that these are complete objects and so we don't need to
1884 // use the non-virtual size or alignment.
1885 QualType type = getContext().getTypeDeclType(ctor->getParent());
1886 CharUnits eltAlignment =
1887 arrayBase.getAlignment()
1888 .alignmentOfArrayElement(getContext().getTypeSizeInChars(type));
1889 Address curAddr = Address(cur, eltAlignment);
1891 // Zero initialize the storage, if requested.
1893 EmitNullInitialization(curAddr, type);
1895 // C++ [class.temporary]p4:
1896 // There are two contexts in which temporaries are destroyed at a different
1897 // point than the end of the full-expression. The first context is when a
1898 // default constructor is called to initialize an element of an array.
1899 // If the constructor has one or more default arguments, the destruction of
1900 // every temporary created in a default argument expression is sequenced
1901 // before the construction of the next array element, if any.
1904 RunCleanupsScope Scope(*this);
1906 // Evaluate the constructor and its arguments in a regular
1907 // partial-destroy cleanup.
1908 if (getLangOpts().Exceptions &&
1909 !ctor->getParent()->hasTrivialDestructor()) {
1910 Destroyer *destroyer = destroyCXXObject;
1911 pushRegularPartialArrayCleanup(arrayBegin, cur, type, eltAlignment,
1915 EmitCXXConstructorCall(ctor, Ctor_Complete, /*ForVirtualBase=*/false,
1916 /*Delegating=*/false, curAddr, E);
1919 // Go to the next element.
1921 Builder.CreateInBoundsGEP(cur, llvm::ConstantInt::get(SizeTy, 1),
1923 cur->addIncoming(next, Builder.GetInsertBlock());
1925 // Check whether that's the end of the loop.
1926 llvm::Value *done = Builder.CreateICmpEQ(next, arrayEnd, "arrayctor.done");
1927 llvm::BasicBlock *contBB = createBasicBlock("arrayctor.cont");
1928 Builder.CreateCondBr(done, contBB, loopBB);
1930 // Patch the earlier check to skip over the loop.
1931 if (zeroCheckBranch) zeroCheckBranch->setSuccessor(0, contBB);
1936 void CodeGenFunction::destroyCXXObject(CodeGenFunction &CGF,
1939 const RecordType *rtype = type->castAs<RecordType>();
1940 const CXXRecordDecl *record = cast<CXXRecordDecl>(rtype->getDecl());
1941 const CXXDestructorDecl *dtor = record->getDestructor();
1942 assert(!dtor->isTrivial());
1943 CGF.EmitCXXDestructorCall(dtor, Dtor_Complete, /*for vbase*/ false,
1944 /*Delegating=*/false, addr);
1947 void CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
1949 bool ForVirtualBase,
1950 bool Delegating, Address This,
1951 const CXXConstructExpr *E) {
1954 // Push the this ptr.
1955 Args.add(RValue::get(This.getPointer()), D->getThisType(getContext()));
1957 // If this is a trivial constructor, emit a memcpy now before we lose
1958 // the alignment information on the argument.
1959 // FIXME: It would be better to preserve alignment information into CallArg.
1960 if (isMemcpyEquivalentSpecialMember(D)) {
1961 assert(E->getNumArgs() == 1 && "unexpected argcount for trivial ctor");
1963 const Expr *Arg = E->getArg(0);
1964 QualType SrcTy = Arg->getType();
1965 Address Src = EmitLValue(Arg).getAddress();
1966 QualType DestTy = getContext().getTypeDeclType(D->getParent());
1967 EmitAggregateCopyCtor(This, Src, DestTy, SrcTy);
1971 // Add the rest of the user-supplied arguments.
1972 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1973 EvaluationOrder Order = E->isListInitialization()
1974 ? EvaluationOrder::ForceLeftToRight
1975 : EvaluationOrder::Default;
1976 EmitCallArgs(Args, FPT, E->arguments(), E->getConstructor(),
1977 /*ParamsToSkip*/ 0, Order);
1979 EmitCXXConstructorCall(D, Type, ForVirtualBase, Delegating, This, Args);
1982 static bool canEmitDelegateCallArgs(CodeGenFunction &CGF,
1983 const CXXConstructorDecl *Ctor,
1984 CXXCtorType Type, CallArgList &Args) {
1985 // We can't forward a variadic call.
1986 if (Ctor->isVariadic())
1989 if (CGF.getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) {
1990 // If the parameters are callee-cleanup, it's not safe to forward.
1991 for (auto *P : Ctor->parameters())
1992 if (P->getType().isDestructedType())
1995 // Likewise if they're inalloca.
1996 const CGFunctionInfo &Info =
1997 CGF.CGM.getTypes().arrangeCXXConstructorCall(Args, Ctor, Type, 0, 0);
1998 if (Info.usesInAlloca())
2002 // Anything else should be OK.
2006 void CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
2008 bool ForVirtualBase,
2011 CallArgList &Args) {
2012 const CXXRecordDecl *ClassDecl = D->getParent();
2014 // C++11 [class.mfct.non-static]p2:
2015 // If a non-static member function of a class X is called for an object that
2016 // is not of type X, or of a type derived from X, the behavior is undefined.
2017 // FIXME: Provide a source location here.
2018 EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall, SourceLocation(),
2019 This.getPointer(), getContext().getRecordType(ClassDecl));
2021 if (D->isTrivial() && D->isDefaultConstructor()) {
2022 assert(Args.size() == 1 && "trivial default ctor with args");
2026 // If this is a trivial constructor, just emit what's needed. If this is a
2027 // union copy constructor, we must emit a memcpy, because the AST does not
2029 if (isMemcpyEquivalentSpecialMember(D)) {
2030 assert(Args.size() == 2 && "unexpected argcount for trivial ctor");
2032 QualType SrcTy = D->getParamDecl(0)->getType().getNonReferenceType();
2033 Address Src(Args[1].RV.getScalarVal(), getNaturalTypeAlignment(SrcTy));
2034 QualType DestTy = getContext().getTypeDeclType(ClassDecl);
2035 EmitAggregateCopyCtor(This, Src, DestTy, SrcTy);
2039 bool PassPrototypeArgs = true;
2040 // Check whether we can actually emit the constructor before trying to do so.
2041 if (auto Inherited = D->getInheritedConstructor()) {
2042 PassPrototypeArgs = getTypes().inheritingCtorHasParams(Inherited, Type);
2043 if (PassPrototypeArgs && !canEmitDelegateCallArgs(*this, D, Type, Args)) {
2044 EmitInlinedInheritingCXXConstructorCall(D, Type, ForVirtualBase,
2050 // Insert any ABI-specific implicit constructor arguments.
2051 CGCXXABI::AddedStructorArgs ExtraArgs =
2052 CGM.getCXXABI().addImplicitConstructorArgs(*this, D, Type, ForVirtualBase,
2056 llvm::Constant *CalleePtr =
2057 CGM.getAddrOfCXXStructor(D, getFromCtorType(Type));
2058 const CGFunctionInfo &Info = CGM.getTypes().arrangeCXXConstructorCall(
2059 Args, D, Type, ExtraArgs.Prefix, ExtraArgs.Suffix, PassPrototypeArgs);
2060 CGCallee Callee = CGCallee::forDirect(CalleePtr, D);
2061 EmitCall(Info, Callee, ReturnValueSlot(), Args);
2063 // Generate vtable assumptions if we're constructing a complete object
2064 // with a vtable. We don't do this for base subobjects for two reasons:
2065 // first, it's incorrect for classes with virtual bases, and second, we're
2066 // about to overwrite the vptrs anyway.
2067 // We also have to make sure if we can refer to vtable:
2068 // - Otherwise we can refer to vtable if it's safe to speculatively emit.
2069 // FIXME: If vtable is used by ctor/dtor, or if vtable is external and we are
2070 // sure that definition of vtable is not hidden,
2071 // then we are always safe to refer to it.
2072 // FIXME: It looks like InstCombine is very inefficient on dealing with
2073 // assumes. Make assumption loads require -fstrict-vtable-pointers temporarily.
2074 if (CGM.getCodeGenOpts().OptimizationLevel > 0 &&
2075 ClassDecl->isDynamicClass() && Type != Ctor_Base &&
2076 CGM.getCXXABI().canSpeculativelyEmitVTable(ClassDecl) &&
2077 CGM.getCodeGenOpts().StrictVTablePointers)
2078 EmitVTableAssumptionLoads(ClassDecl, This);
2081 void CodeGenFunction::EmitInheritedCXXConstructorCall(
2082 const CXXConstructorDecl *D, bool ForVirtualBase, Address This,
2083 bool InheritedFromVBase, const CXXInheritedCtorInitExpr *E) {
2085 CallArg ThisArg(RValue::get(This.getPointer()), D->getThisType(getContext()),
2086 /*NeedsCopy=*/false);
2088 // Forward the parameters.
2089 if (InheritedFromVBase &&
2090 CGM.getTarget().getCXXABI().hasConstructorVariants()) {
2091 // Nothing to do; this construction is not responsible for constructing
2092 // the base class containing the inherited constructor.
2093 // FIXME: Can we just pass undef's for the remaining arguments if we don't
2094 // have constructor variants?
2095 Args.push_back(ThisArg);
2096 } else if (!CXXInheritedCtorInitExprArgs.empty()) {
2097 // The inheriting constructor was inlined; just inject its arguments.
2098 assert(CXXInheritedCtorInitExprArgs.size() >= D->getNumParams() &&
2099 "wrong number of parameters for inherited constructor call");
2100 Args = CXXInheritedCtorInitExprArgs;
2103 // The inheriting constructor was not inlined. Emit delegating arguments.
2104 Args.push_back(ThisArg);
2105 const auto *OuterCtor = cast<CXXConstructorDecl>(CurCodeDecl);
2106 assert(OuterCtor->getNumParams() == D->getNumParams());
2107 assert(!OuterCtor->isVariadic() && "should have been inlined");
2109 for (const auto *Param : OuterCtor->parameters()) {
2110 assert(getContext().hasSameUnqualifiedType(
2111 OuterCtor->getParamDecl(Param->getFunctionScopeIndex())->getType(),
2113 EmitDelegateCallArg(Args, Param, E->getLocation());
2115 // Forward __attribute__(pass_object_size).
2116 if (Param->hasAttr<PassObjectSizeAttr>()) {
2117 auto *POSParam = SizeArguments[Param];
2118 assert(POSParam && "missing pass_object_size value for forwarding");
2119 EmitDelegateCallArg(Args, POSParam, E->getLocation());
2124 EmitCXXConstructorCall(D, Ctor_Base, ForVirtualBase, /*Delegating*/false,
2128 void CodeGenFunction::EmitInlinedInheritingCXXConstructorCall(
2129 const CXXConstructorDecl *Ctor, CXXCtorType CtorType, bool ForVirtualBase,
2130 bool Delegating, CallArgList &Args) {
2131 GlobalDecl GD(Ctor, CtorType);
2132 InlinedInheritingConstructorScope Scope(*this, GD);
2133 ApplyInlineDebugLocation DebugScope(*this, GD);
2135 // Save the arguments to be passed to the inherited constructor.
2136 CXXInheritedCtorInitExprArgs = Args;
2138 FunctionArgList Params;
2139 QualType RetType = BuildFunctionArgList(CurGD, Params);
2142 // Insert any ABI-specific implicit constructor arguments.
2143 CGM.getCXXABI().addImplicitConstructorArgs(*this, Ctor, CtorType,
2144 ForVirtualBase, Delegating, Args);
2146 // Emit a simplified prolog. We only need to emit the implicit params.
2147 assert(Args.size() >= Params.size() && "too few arguments for call");
2148 for (unsigned I = 0, N = Args.size(); I != N; ++I) {
2149 if (I < Params.size() && isa<ImplicitParamDecl>(Params[I])) {
2150 const RValue &RV = Args[I].RV;
2151 assert(!RV.isComplex() && "complex indirect params not supported");
2152 ParamValue Val = RV.isScalar()
2153 ? ParamValue::forDirect(RV.getScalarVal())
2154 : ParamValue::forIndirect(RV.getAggregateAddress());
2155 EmitParmDecl(*Params[I], Val, I + 1);
2159 // Create a return value slot if the ABI implementation wants one.
2160 // FIXME: This is dumb, we should ask the ABI not to try to set the return
2162 if (!RetType->isVoidType())
2163 ReturnValue = CreateIRTemp(RetType, "retval.inhctor");
2165 CGM.getCXXABI().EmitInstanceFunctionProlog(*this);
2166 CXXThisValue = CXXABIThisValue;
2168 // Directly emit the constructor initializers.
2169 EmitCtorPrologue(Ctor, CtorType, Params);
2172 void CodeGenFunction::EmitVTableAssumptionLoad(const VPtr &Vptr, Address This) {
2173 llvm::Value *VTableGlobal =
2174 CGM.getCXXABI().getVTableAddressPoint(Vptr.Base, Vptr.VTableClass);
2178 // We can just use the base offset in the complete class.
2179 CharUnits NonVirtualOffset = Vptr.Base.getBaseOffset();
2181 if (!NonVirtualOffset.isZero())
2183 ApplyNonVirtualAndVirtualOffset(*this, This, NonVirtualOffset, nullptr,
2184 Vptr.VTableClass, Vptr.NearestVBase);
2186 llvm::Value *VPtrValue =
2187 GetVTablePtr(This, VTableGlobal->getType(), Vptr.VTableClass);
2189 Builder.CreateICmpEQ(VPtrValue, VTableGlobal, "cmp.vtables");
2190 Builder.CreateAssumption(Cmp);
2193 void CodeGenFunction::EmitVTableAssumptionLoads(const CXXRecordDecl *ClassDecl,
2195 if (CGM.getCXXABI().doStructorsInitializeVPtrs(ClassDecl))
2196 for (const VPtr &Vptr : getVTablePointers(ClassDecl))
2197 EmitVTableAssumptionLoad(Vptr, This);
2201 CodeGenFunction::EmitSynthesizedCXXCopyCtorCall(const CXXConstructorDecl *D,
2202 Address This, Address Src,
2203 const CXXConstructExpr *E) {
2204 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
2208 // Push the this ptr.
2209 Args.add(RValue::get(This.getPointer()), D->getThisType(getContext()));
2211 // Push the src ptr.
2212 QualType QT = *(FPT->param_type_begin());
2213 llvm::Type *t = CGM.getTypes().ConvertType(QT);
2214 Src = Builder.CreateBitCast(Src, t);
2215 Args.add(RValue::get(Src.getPointer()), QT);
2217 // Skip over first argument (Src).
2218 EmitCallArgs(Args, FPT, drop_begin(E->arguments(), 1), E->getConstructor(),
2219 /*ParamsToSkip*/ 1);
2221 EmitCXXConstructorCall(D, Ctor_Complete, false, false, This, Args);
2225 CodeGenFunction::EmitDelegateCXXConstructorCall(const CXXConstructorDecl *Ctor,
2226 CXXCtorType CtorType,
2227 const FunctionArgList &Args,
2228 SourceLocation Loc) {
2229 CallArgList DelegateArgs;
2231 FunctionArgList::const_iterator I = Args.begin(), E = Args.end();
2232 assert(I != E && "no parameters to constructor");
2235 Address This = LoadCXXThisAddress();
2236 DelegateArgs.add(RValue::get(This.getPointer()), (*I)->getType());
2239 // FIXME: The location of the VTT parameter in the parameter list is
2240 // specific to the Itanium ABI and shouldn't be hardcoded here.
2241 if (CGM.getCXXABI().NeedsVTTParameter(CurGD)) {
2242 assert(I != E && "cannot skip vtt parameter, already done with args");
2243 assert((*I)->getType()->isPointerType() &&
2244 "skipping parameter not of vtt type");
2248 // Explicit arguments.
2249 for (; I != E; ++I) {
2250 const VarDecl *param = *I;
2251 // FIXME: per-argument source location
2252 EmitDelegateCallArg(DelegateArgs, param, Loc);
2255 EmitCXXConstructorCall(Ctor, CtorType, /*ForVirtualBase=*/false,
2256 /*Delegating=*/true, This, DelegateArgs);
2260 struct CallDelegatingCtorDtor final : EHScopeStack::Cleanup {
2261 const CXXDestructorDecl *Dtor;
2265 CallDelegatingCtorDtor(const CXXDestructorDecl *D, Address Addr,
2267 : Dtor(D), Addr(Addr), Type(Type) {}
2269 void Emit(CodeGenFunction &CGF, Flags flags) override {
2270 CGF.EmitCXXDestructorCall(Dtor, Type, /*ForVirtualBase=*/false,
2271 /*Delegating=*/true, Addr);
2274 } // end anonymous namespace
2277 CodeGenFunction::EmitDelegatingCXXConstructorCall(const CXXConstructorDecl *Ctor,
2278 const FunctionArgList &Args) {
2279 assert(Ctor->isDelegatingConstructor());
2281 Address ThisPtr = LoadCXXThisAddress();
2283 AggValueSlot AggSlot =
2284 AggValueSlot::forAddr(ThisPtr, Qualifiers(),
2285 AggValueSlot::IsDestructed,
2286 AggValueSlot::DoesNotNeedGCBarriers,
2287 AggValueSlot::IsNotAliased);
2289 EmitAggExpr(Ctor->init_begin()[0]->getInit(), AggSlot);
2291 const CXXRecordDecl *ClassDecl = Ctor->getParent();
2292 if (CGM.getLangOpts().Exceptions && !ClassDecl->hasTrivialDestructor()) {
2294 CurGD.getCtorType() == Ctor_Complete ? Dtor_Complete : Dtor_Base;
2296 EHStack.pushCleanup<CallDelegatingCtorDtor>(EHCleanup,
2297 ClassDecl->getDestructor(),
2302 void CodeGenFunction::EmitCXXDestructorCall(const CXXDestructorDecl *DD,
2304 bool ForVirtualBase,
2307 CGM.getCXXABI().EmitDestructorCall(*this, DD, Type, ForVirtualBase,
2312 struct CallLocalDtor final : EHScopeStack::Cleanup {
2313 const CXXDestructorDecl *Dtor;
2316 CallLocalDtor(const CXXDestructorDecl *D, Address Addr)
2317 : Dtor(D), Addr(Addr) {}
2319 void Emit(CodeGenFunction &CGF, Flags flags) override {
2320 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
2321 /*ForVirtualBase=*/false,
2322 /*Delegating=*/false, Addr);
2325 } // end anonymous namespace
2327 void CodeGenFunction::PushDestructorCleanup(const CXXDestructorDecl *D,
2329 EHStack.pushCleanup<CallLocalDtor>(NormalAndEHCleanup, D, Addr);
2332 void CodeGenFunction::PushDestructorCleanup(QualType T, Address Addr) {
2333 CXXRecordDecl *ClassDecl = T->getAsCXXRecordDecl();
2334 if (!ClassDecl) return;
2335 if (ClassDecl->hasTrivialDestructor()) return;
2337 const CXXDestructorDecl *D = ClassDecl->getDestructor();
2338 assert(D && D->isUsed() && "destructor not marked as used!");
2339 PushDestructorCleanup(D, Addr);
2342 void CodeGenFunction::InitializeVTablePointer(const VPtr &Vptr) {
2343 // Compute the address point.
2344 llvm::Value *VTableAddressPoint =
2345 CGM.getCXXABI().getVTableAddressPointInStructor(
2346 *this, Vptr.VTableClass, Vptr.Base, Vptr.NearestVBase);
2348 if (!VTableAddressPoint)
2351 // Compute where to store the address point.
2352 llvm::Value *VirtualOffset = nullptr;
2353 CharUnits NonVirtualOffset = CharUnits::Zero();
2355 if (CGM.getCXXABI().isVirtualOffsetNeededForVTableField(*this, Vptr)) {
2356 // We need to use the virtual base offset offset because the virtual base
2357 // might have a different offset in the most derived class.
2359 VirtualOffset = CGM.getCXXABI().GetVirtualBaseClassOffset(
2360 *this, LoadCXXThisAddress(), Vptr.VTableClass, Vptr.NearestVBase);
2361 NonVirtualOffset = Vptr.OffsetFromNearestVBase;
2363 // We can just use the base offset in the complete class.
2364 NonVirtualOffset = Vptr.Base.getBaseOffset();
2367 // Apply the offsets.
2368 Address VTableField = LoadCXXThisAddress();
2370 if (!NonVirtualOffset.isZero() || VirtualOffset)
2371 VTableField = ApplyNonVirtualAndVirtualOffset(
2372 *this, VTableField, NonVirtualOffset, VirtualOffset, Vptr.VTableClass,
2375 // Finally, store the address point. Use the same LLVM types as the field to
2376 // support optimization.
2377 llvm::Type *VTablePtrTy =
2378 llvm::FunctionType::get(CGM.Int32Ty, /*isVarArg=*/true)
2381 VTableField = Builder.CreateBitCast(VTableField, VTablePtrTy->getPointerTo());
2382 VTableAddressPoint = Builder.CreateBitCast(VTableAddressPoint, VTablePtrTy);
2384 llvm::StoreInst *Store = Builder.CreateStore(VTableAddressPoint, VTableField);
2385 CGM.DecorateInstructionWithTBAA(Store, CGM.getTBAAInfoForVTablePtr());
2386 if (CGM.getCodeGenOpts().OptimizationLevel > 0 &&
2387 CGM.getCodeGenOpts().StrictVTablePointers)
2388 CGM.DecorateInstructionWithInvariantGroup(Store, Vptr.VTableClass);
2391 CodeGenFunction::VPtrsVector
2392 CodeGenFunction::getVTablePointers(const CXXRecordDecl *VTableClass) {
2393 CodeGenFunction::VPtrsVector VPtrsResult;
2394 VisitedVirtualBasesSetTy VBases;
2395 getVTablePointers(BaseSubobject(VTableClass, CharUnits::Zero()),
2396 /*NearestVBase=*/nullptr,
2397 /*OffsetFromNearestVBase=*/CharUnits::Zero(),
2398 /*BaseIsNonVirtualPrimaryBase=*/false, VTableClass, VBases,
2403 void CodeGenFunction::getVTablePointers(BaseSubobject Base,
2404 const CXXRecordDecl *NearestVBase,
2405 CharUnits OffsetFromNearestVBase,
2406 bool BaseIsNonVirtualPrimaryBase,
2407 const CXXRecordDecl *VTableClass,
2408 VisitedVirtualBasesSetTy &VBases,
2409 VPtrsVector &Vptrs) {
2410 // If this base is a non-virtual primary base the address point has already
2412 if (!BaseIsNonVirtualPrimaryBase) {
2413 // Initialize the vtable pointer for this base.
2414 VPtr Vptr = {Base, NearestVBase, OffsetFromNearestVBase, VTableClass};
2415 Vptrs.push_back(Vptr);
2418 const CXXRecordDecl *RD = Base.getBase();
2421 for (const auto &I : RD->bases()) {
2422 CXXRecordDecl *BaseDecl
2423 = cast<CXXRecordDecl>(I.getType()->getAs<RecordType>()->getDecl());
2425 // Ignore classes without a vtable.
2426 if (!BaseDecl->isDynamicClass())
2429 CharUnits BaseOffset;
2430 CharUnits BaseOffsetFromNearestVBase;
2431 bool BaseDeclIsNonVirtualPrimaryBase;
2433 if (I.isVirtual()) {
2434 // Check if we've visited this virtual base before.
2435 if (!VBases.insert(BaseDecl).second)
2438 const ASTRecordLayout &Layout =
2439 getContext().getASTRecordLayout(VTableClass);
2441 BaseOffset = Layout.getVBaseClassOffset(BaseDecl);
2442 BaseOffsetFromNearestVBase = CharUnits::Zero();
2443 BaseDeclIsNonVirtualPrimaryBase = false;
2445 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
2447 BaseOffset = Base.getBaseOffset() + Layout.getBaseClassOffset(BaseDecl);
2448 BaseOffsetFromNearestVBase =
2449 OffsetFromNearestVBase + Layout.getBaseClassOffset(BaseDecl);
2450 BaseDeclIsNonVirtualPrimaryBase = Layout.getPrimaryBase() == BaseDecl;
2454 BaseSubobject(BaseDecl, BaseOffset),
2455 I.isVirtual() ? BaseDecl : NearestVBase, BaseOffsetFromNearestVBase,
2456 BaseDeclIsNonVirtualPrimaryBase, VTableClass, VBases, Vptrs);
2460 void CodeGenFunction::InitializeVTablePointers(const CXXRecordDecl *RD) {
2461 // Ignore classes without a vtable.
2462 if (!RD->isDynamicClass())
2465 // Initialize the vtable pointers for this class and all of its bases.
2466 if (CGM.getCXXABI().doStructorsInitializeVPtrs(RD))
2467 for (const VPtr &Vptr : getVTablePointers(RD))
2468 InitializeVTablePointer(Vptr);
2470 if (RD->getNumVBases())
2471 CGM.getCXXABI().initializeHiddenVirtualInheritanceMembers(*this, RD);
2474 llvm::Value *CodeGenFunction::GetVTablePtr(Address This,
2475 llvm::Type *VTableTy,
2476 const CXXRecordDecl *RD) {
2477 Address VTablePtrSrc = Builder.CreateElementBitCast(This, VTableTy);
2478 llvm::Instruction *VTable = Builder.CreateLoad(VTablePtrSrc, "vtable");
2479 CGM.DecorateInstructionWithTBAA(VTable, CGM.getTBAAInfoForVTablePtr());
2481 if (CGM.getCodeGenOpts().OptimizationLevel > 0 &&
2482 CGM.getCodeGenOpts().StrictVTablePointers)
2483 CGM.DecorateInstructionWithInvariantGroup(VTable, RD);
2488 // If a class has a single non-virtual base and does not introduce or override
2489 // virtual member functions or fields, it will have the same layout as its base.
2490 // This function returns the least derived such class.
2492 // Casting an instance of a base class to such a derived class is technically
2493 // undefined behavior, but it is a relatively common hack for introducing member
2494 // functions on class instances with specific properties (e.g. llvm::Operator)
2495 // that works under most compilers and should not have security implications, so
2496 // we allow it by default. It can be disabled with -fsanitize=cfi-cast-strict.
2497 static const CXXRecordDecl *
2498 LeastDerivedClassWithSameLayout(const CXXRecordDecl *RD) {
2499 if (!RD->field_empty())
2502 if (RD->getNumVBases() != 0)
2505 if (RD->getNumBases() != 1)
2508 for (const CXXMethodDecl *MD : RD->methods()) {
2509 if (MD->isVirtual()) {
2510 // Virtual member functions are only ok if they are implicit destructors
2511 // because the implicit destructor will have the same semantics as the
2512 // base class's destructor if no fields are added.
2513 if (isa<CXXDestructorDecl>(MD) && MD->isImplicit())
2519 return LeastDerivedClassWithSameLayout(
2520 RD->bases_begin()->getType()->getAsCXXRecordDecl());
2523 void CodeGenFunction::EmitTypeMetadataCodeForVCall(const CXXRecordDecl *RD,
2524 llvm::Value *VTable,
2525 SourceLocation Loc) {
2526 if (CGM.getCodeGenOpts().WholeProgramVTables &&
2527 CGM.HasHiddenLTOVisibility(RD)) {
2528 llvm::Metadata *MD =
2529 CGM.CreateMetadataIdentifierForType(QualType(RD->getTypeForDecl(), 0));
2530 llvm::Value *TypeId =
2531 llvm::MetadataAsValue::get(CGM.getLLVMContext(), MD);
2533 llvm::Value *CastedVTable = Builder.CreateBitCast(VTable, Int8PtrTy);
2534 llvm::Value *TypeTest =
2535 Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::type_test),
2536 {CastedVTable, TypeId});
2537 Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::assume), TypeTest);
2540 if (SanOpts.has(SanitizerKind::CFIVCall))
2541 EmitVTablePtrCheckForCall(RD, VTable, CodeGenFunction::CFITCK_VCall, Loc);
2544 void CodeGenFunction::EmitVTablePtrCheckForCall(const CXXRecordDecl *RD,
2545 llvm::Value *VTable,
2546 CFITypeCheckKind TCK,
2547 SourceLocation Loc) {
2548 if (!SanOpts.has(SanitizerKind::CFICastStrict))
2549 RD = LeastDerivedClassWithSameLayout(RD);
2551 EmitVTablePtrCheck(RD, VTable, TCK, Loc);
2554 void CodeGenFunction::EmitVTablePtrCheckForCast(QualType T,
2555 llvm::Value *Derived,
2557 CFITypeCheckKind TCK,
2558 SourceLocation Loc) {
2559 if (!getLangOpts().CPlusPlus)
2562 auto *ClassTy = T->getAs<RecordType>();
2566 const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(ClassTy->getDecl());
2568 if (!ClassDecl->isCompleteDefinition() || !ClassDecl->isDynamicClass())
2571 if (!SanOpts.has(SanitizerKind::CFICastStrict))
2572 ClassDecl = LeastDerivedClassWithSameLayout(ClassDecl);
2574 llvm::BasicBlock *ContBlock = nullptr;
2577 llvm::Value *DerivedNotNull =
2578 Builder.CreateIsNotNull(Derived, "cast.nonnull");
2580 llvm::BasicBlock *CheckBlock = createBasicBlock("cast.check");
2581 ContBlock = createBasicBlock("cast.cont");
2583 Builder.CreateCondBr(DerivedNotNull, CheckBlock, ContBlock);
2585 EmitBlock(CheckBlock);
2588 llvm::Value *VTable =
2589 GetVTablePtr(Address(Derived, getPointerAlign()), Int8PtrTy, ClassDecl);
2591 EmitVTablePtrCheck(ClassDecl, VTable, TCK, Loc);
2594 Builder.CreateBr(ContBlock);
2595 EmitBlock(ContBlock);
2599 void CodeGenFunction::EmitVTablePtrCheck(const CXXRecordDecl *RD,
2600 llvm::Value *VTable,
2601 CFITypeCheckKind TCK,
2602 SourceLocation Loc) {
2603 if (!CGM.getCodeGenOpts().SanitizeCfiCrossDso &&
2604 !CGM.HasHiddenLTOVisibility(RD))
2607 std::string TypeName = RD->getQualifiedNameAsString();
2608 if (getContext().getSanitizerBlacklist().isBlacklistedType(TypeName))
2611 SanitizerScope SanScope(this);
2612 llvm::SanitizerStatKind SSK;
2615 SSK = llvm::SanStat_CFI_VCall;
2618 SSK = llvm::SanStat_CFI_NVCall;
2620 case CFITCK_DerivedCast:
2621 SSK = llvm::SanStat_CFI_DerivedCast;
2623 case CFITCK_UnrelatedCast:
2624 SSK = llvm::SanStat_CFI_UnrelatedCast;
2627 llvm_unreachable("not expecting CFITCK_ICall");
2629 EmitSanitizerStatReport(SSK);
2631 llvm::Metadata *MD =
2632 CGM.CreateMetadataIdentifierForType(QualType(RD->getTypeForDecl(), 0));
2633 llvm::Value *TypeId = llvm::MetadataAsValue::get(getLLVMContext(), MD);
2635 llvm::Value *CastedVTable = Builder.CreateBitCast(VTable, Int8PtrTy);
2636 llvm::Value *TypeTest = Builder.CreateCall(
2637 CGM.getIntrinsic(llvm::Intrinsic::type_test), {CastedVTable, TypeId});
2642 M = SanitizerKind::CFIVCall;
2645 M = SanitizerKind::CFINVCall;
2647 case CFITCK_DerivedCast:
2648 M = SanitizerKind::CFIDerivedCast;
2650 case CFITCK_UnrelatedCast:
2651 M = SanitizerKind::CFIUnrelatedCast;
2654 llvm_unreachable("not expecting CFITCK_ICall");
2657 llvm::Constant *StaticData[] = {
2658 llvm::ConstantInt::get(Int8Ty, TCK),
2659 EmitCheckSourceLocation(Loc),
2660 EmitCheckTypeDescriptor(QualType(RD->getTypeForDecl(), 0)),
2663 auto CrossDsoTypeId = CGM.CreateCrossDsoCfiTypeId(MD);
2664 if (CGM.getCodeGenOpts().SanitizeCfiCrossDso && CrossDsoTypeId) {
2665 EmitCfiSlowPathCheck(M, TypeTest, CrossDsoTypeId, CastedVTable, StaticData);
2669 if (CGM.getCodeGenOpts().SanitizeTrap.has(M)) {
2670 EmitTrapCheck(TypeTest);
2674 llvm::Value *AllVtables = llvm::MetadataAsValue::get(
2675 CGM.getLLVMContext(),
2676 llvm::MDString::get(CGM.getLLVMContext(), "all-vtables"));
2677 llvm::Value *ValidVtable = Builder.CreateCall(
2678 CGM.getIntrinsic(llvm::Intrinsic::type_test), {CastedVTable, AllVtables});
2679 EmitCheck(std::make_pair(TypeTest, M), SanitizerHandler::CFICheckFail,
2680 StaticData, {CastedVTable, ValidVtable});
2683 bool CodeGenFunction::ShouldEmitVTableTypeCheckedLoad(const CXXRecordDecl *RD) {
2684 if (!CGM.getCodeGenOpts().WholeProgramVTables ||
2685 !SanOpts.has(SanitizerKind::CFIVCall) ||
2686 !CGM.getCodeGenOpts().SanitizeTrap.has(SanitizerKind::CFIVCall) ||
2687 !CGM.HasHiddenLTOVisibility(RD))
2690 std::string TypeName = RD->getQualifiedNameAsString();
2691 return !getContext().getSanitizerBlacklist().isBlacklistedType(TypeName);
2694 llvm::Value *CodeGenFunction::EmitVTableTypeCheckedLoad(
2695 const CXXRecordDecl *RD, llvm::Value *VTable, uint64_t VTableByteOffset) {
2696 SanitizerScope SanScope(this);
2698 EmitSanitizerStatReport(llvm::SanStat_CFI_VCall);
2700 llvm::Metadata *MD =
2701 CGM.CreateMetadataIdentifierForType(QualType(RD->getTypeForDecl(), 0));
2702 llvm::Value *TypeId = llvm::MetadataAsValue::get(CGM.getLLVMContext(), MD);
2704 llvm::Value *CastedVTable = Builder.CreateBitCast(VTable, Int8PtrTy);
2705 llvm::Value *CheckedLoad = Builder.CreateCall(
2706 CGM.getIntrinsic(llvm::Intrinsic::type_checked_load),
2707 {CastedVTable, llvm::ConstantInt::get(Int32Ty, VTableByteOffset),
2709 llvm::Value *CheckResult = Builder.CreateExtractValue(CheckedLoad, 1);
2711 EmitCheck(std::make_pair(CheckResult, SanitizerKind::CFIVCall),
2712 SanitizerHandler::CFICheckFail, nullptr, nullptr);
2714 return Builder.CreateBitCast(
2715 Builder.CreateExtractValue(CheckedLoad, 0),
2716 cast<llvm::PointerType>(VTable->getType())->getElementType());
2719 void CodeGenFunction::EmitForwardingCallToLambda(
2720 const CXXMethodDecl *callOperator,
2721 CallArgList &callArgs) {
2722 // Get the address of the call operator.
2723 const CGFunctionInfo &calleeFnInfo =
2724 CGM.getTypes().arrangeCXXMethodDeclaration(callOperator);
2725 llvm::Constant *calleePtr =
2726 CGM.GetAddrOfFunction(GlobalDecl(callOperator),
2727 CGM.getTypes().GetFunctionType(calleeFnInfo));
2729 // Prepare the return slot.
2730 const FunctionProtoType *FPT =
2731 callOperator->getType()->castAs<FunctionProtoType>();
2732 QualType resultType = FPT->getReturnType();
2733 ReturnValueSlot returnSlot;
2734 if (!resultType->isVoidType() &&
2735 calleeFnInfo.getReturnInfo().getKind() == ABIArgInfo::Indirect &&
2736 !hasScalarEvaluationKind(calleeFnInfo.getReturnType()))
2737 returnSlot = ReturnValueSlot(ReturnValue, resultType.isVolatileQualified());
2739 // We don't need to separately arrange the call arguments because
2740 // the call can't be variadic anyway --- it's impossible to forward
2741 // variadic arguments.
2743 // Now emit our call.
2744 auto callee = CGCallee::forDirect(calleePtr, callOperator);
2745 RValue RV = EmitCall(calleeFnInfo, callee, returnSlot, callArgs);
2747 // If necessary, copy the returned value into the slot.
2748 if (!resultType->isVoidType() && returnSlot.isNull())
2749 EmitReturnOfRValue(RV, resultType);
2751 EmitBranchThroughCleanup(ReturnBlock);
2754 void CodeGenFunction::EmitLambdaBlockInvokeBody() {
2755 const BlockDecl *BD = BlockInfo->getBlockDecl();
2756 const VarDecl *variable = BD->capture_begin()->getVariable();
2757 const CXXRecordDecl *Lambda = variable->getType()->getAsCXXRecordDecl();
2759 // Start building arguments for forwarding call
2760 CallArgList CallArgs;
2762 QualType ThisType = getContext().getPointerType(getContext().getRecordType(Lambda));
2763 Address ThisPtr = GetAddrOfBlockDecl(variable, false);
2764 CallArgs.add(RValue::get(ThisPtr.getPointer()), ThisType);
2766 // Add the rest of the parameters.
2767 for (auto param : BD->parameters())
2768 EmitDelegateCallArg(CallArgs, param, param->getLocStart());
2770 assert(!Lambda->isGenericLambda() &&
2771 "generic lambda interconversion to block not implemented");
2772 EmitForwardingCallToLambda(Lambda->getLambdaCallOperator(), CallArgs);
2775 void CodeGenFunction::EmitLambdaToBlockPointerBody(FunctionArgList &Args) {
2776 if (cast<CXXMethodDecl>(CurCodeDecl)->isVariadic()) {
2777 // FIXME: Making this work correctly is nasty because it requires either
2778 // cloning the body of the call operator or making the call operator forward.
2779 CGM.ErrorUnsupported(CurCodeDecl, "lambda conversion to variadic function");
2783 EmitFunctionBody(Args, cast<FunctionDecl>(CurGD.getDecl())->getBody());
2786 void CodeGenFunction::EmitLambdaDelegatingInvokeBody(const CXXMethodDecl *MD) {
2787 const CXXRecordDecl *Lambda = MD->getParent();
2789 // Start building arguments for forwarding call
2790 CallArgList CallArgs;
2792 QualType ThisType = getContext().getPointerType(getContext().getRecordType(Lambda));
2793 llvm::Value *ThisPtr = llvm::UndefValue::get(getTypes().ConvertType(ThisType));
2794 CallArgs.add(RValue::get(ThisPtr), ThisType);
2796 // Add the rest of the parameters.
2797 for (auto Param : MD->parameters())
2798 EmitDelegateCallArg(CallArgs, Param, Param->getLocStart());
2800 const CXXMethodDecl *CallOp = Lambda->getLambdaCallOperator();
2801 // For a generic lambda, find the corresponding call operator specialization
2802 // to which the call to the static-invoker shall be forwarded.
2803 if (Lambda->isGenericLambda()) {
2804 assert(MD->isFunctionTemplateSpecialization());
2805 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
2806 FunctionTemplateDecl *CallOpTemplate = CallOp->getDescribedFunctionTemplate();
2807 void *InsertPos = nullptr;
2808 FunctionDecl *CorrespondingCallOpSpecialization =
2809 CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos);
2810 assert(CorrespondingCallOpSpecialization);
2811 CallOp = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
2813 EmitForwardingCallToLambda(CallOp, CallArgs);
2816 void CodeGenFunction::EmitLambdaStaticInvokeFunction(const CXXMethodDecl *MD) {
2817 if (MD->isVariadic()) {
2818 // FIXME: Making this work correctly is nasty because it requires either
2819 // cloning the body of the call operator or making the call operator forward.
2820 CGM.ErrorUnsupported(MD, "lambda conversion to variadic function");
2824 EmitLambdaDelegatingInvokeBody(MD);