1 //===--- CGClass.cpp - Emit LLVM Code for C++ classes ---------------------===//
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"
29 using namespace clang;
30 using namespace CodeGen;
32 CharUnits CodeGenModule::computeNonVirtualBaseClassOffset(
33 const CXXRecordDecl *DerivedClass, CastExpr::path_const_iterator Start,
34 CastExpr::path_const_iterator End) {
35 CharUnits Offset = CharUnits::Zero();
37 const ASTContext &Context = getContext();
38 const CXXRecordDecl *RD = DerivedClass;
40 for (CastExpr::path_const_iterator I = Start; I != End; ++I) {
41 const CXXBaseSpecifier *Base = *I;
42 assert(!Base->isVirtual() && "Should not see virtual bases here!");
45 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
47 const CXXRecordDecl *BaseDecl =
48 cast<CXXRecordDecl>(Base->getType()->getAs<RecordType>()->getDecl());
51 Offset += Layout.getBaseClassOffset(BaseDecl);
60 CodeGenModule::GetNonVirtualBaseClassOffset(const CXXRecordDecl *ClassDecl,
61 CastExpr::path_const_iterator PathBegin,
62 CastExpr::path_const_iterator PathEnd) {
63 assert(PathBegin != PathEnd && "Base path should not be empty!");
66 computeNonVirtualBaseClassOffset(ClassDecl, PathBegin, PathEnd);
70 llvm::Type *PtrDiffTy =
71 Types.ConvertType(getContext().getPointerDiffType());
73 return llvm::ConstantInt::get(PtrDiffTy, Offset.getQuantity());
76 /// Gets the address of a direct base class within a complete object.
77 /// This should only be used for (1) non-virtual bases or (2) virtual bases
78 /// when the type is known to be complete (e.g. in complete destructors).
80 /// The object pointed to by 'This' is assumed to be non-null.
82 CodeGenFunction::GetAddressOfDirectBaseInCompleteClass(llvm::Value *This,
83 const CXXRecordDecl *Derived,
84 const CXXRecordDecl *Base,
86 // 'this' must be a pointer (in some address space) to Derived.
87 assert(This->getType()->isPointerTy() &&
88 cast<llvm::PointerType>(This->getType())->getElementType()
89 == ConvertType(Derived));
91 // Compute the offset of the virtual base.
93 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(Derived);
95 Offset = Layout.getVBaseClassOffset(Base);
97 Offset = Layout.getBaseClassOffset(Base);
99 // Shift and cast down to the base type.
100 // TODO: for complete types, this should be possible with a GEP.
101 llvm::Value *V = This;
102 if (Offset.isPositive()) {
103 V = Builder.CreateBitCast(V, Int8PtrTy);
104 V = Builder.CreateConstInBoundsGEP1_64(V, Offset.getQuantity());
106 V = Builder.CreateBitCast(V, ConvertType(Base)->getPointerTo());
112 ApplyNonVirtualAndVirtualOffset(CodeGenFunction &CGF, llvm::Value *ptr,
113 CharUnits nonVirtualOffset,
114 llvm::Value *virtualOffset) {
115 // Assert that we have something to do.
116 assert(!nonVirtualOffset.isZero() || virtualOffset != nullptr);
118 // Compute the offset from the static and dynamic components.
119 llvm::Value *baseOffset;
120 if (!nonVirtualOffset.isZero()) {
121 baseOffset = llvm::ConstantInt::get(CGF.PtrDiffTy,
122 nonVirtualOffset.getQuantity());
124 baseOffset = CGF.Builder.CreateAdd(virtualOffset, baseOffset);
127 baseOffset = virtualOffset;
130 // Apply the base offset.
131 ptr = CGF.Builder.CreateBitCast(ptr, CGF.Int8PtrTy);
132 ptr = CGF.Builder.CreateInBoundsGEP(ptr, baseOffset, "add.ptr");
136 llvm::Value *CodeGenFunction::GetAddressOfBaseClass(
137 llvm::Value *Value, const CXXRecordDecl *Derived,
138 CastExpr::path_const_iterator PathBegin,
139 CastExpr::path_const_iterator PathEnd, bool NullCheckValue,
140 SourceLocation Loc) {
141 assert(PathBegin != PathEnd && "Base path should not be empty!");
143 CastExpr::path_const_iterator Start = PathBegin;
144 const CXXRecordDecl *VBase = nullptr;
146 // Sema has done some convenient canonicalization here: if the
147 // access path involved any virtual steps, the conversion path will
148 // *start* with a step down to the correct virtual base subobject,
149 // and hence will not require any further steps.
150 if ((*Start)->isVirtual()) {
152 cast<CXXRecordDecl>((*Start)->getType()->getAs<RecordType>()->getDecl());
156 // Compute the static offset of the ultimate destination within its
157 // allocating subobject (the virtual base, if there is one, or else
158 // the "complete" object that we see).
159 CharUnits NonVirtualOffset = CGM.computeNonVirtualBaseClassOffset(
160 VBase ? VBase : Derived, Start, PathEnd);
162 // If there's a virtual step, we can sometimes "devirtualize" it.
163 // For now, that's limited to when the derived type is final.
164 // TODO: "devirtualize" this for accesses to known-complete objects.
165 if (VBase && Derived->hasAttr<FinalAttr>()) {
166 const ASTRecordLayout &layout = getContext().getASTRecordLayout(Derived);
167 CharUnits vBaseOffset = layout.getVBaseClassOffset(VBase);
168 NonVirtualOffset += vBaseOffset;
169 VBase = nullptr; // we no longer have a virtual step
172 // Get the base pointer type.
173 llvm::Type *BasePtrTy =
174 ConvertType((PathEnd[-1])->getType())->getPointerTo();
176 QualType DerivedTy = getContext().getRecordType(Derived);
177 CharUnits DerivedAlign = getContext().getTypeAlignInChars(DerivedTy);
179 // If the static offset is zero and we don't have a virtual step,
180 // just do a bitcast; null checks are unnecessary.
181 if (NonVirtualOffset.isZero() && !VBase) {
182 if (sanitizePerformTypeCheck()) {
183 EmitTypeCheck(TCK_Upcast, Loc, Value, DerivedTy, DerivedAlign,
186 return Builder.CreateBitCast(Value, BasePtrTy);
189 llvm::BasicBlock *origBB = nullptr;
190 llvm::BasicBlock *endBB = nullptr;
192 // Skip over the offset (and the vtable load) if we're supposed to
193 // null-check the pointer.
194 if (NullCheckValue) {
195 origBB = Builder.GetInsertBlock();
196 llvm::BasicBlock *notNullBB = createBasicBlock("cast.notnull");
197 endBB = createBasicBlock("cast.end");
199 llvm::Value *isNull = Builder.CreateIsNull(Value);
200 Builder.CreateCondBr(isNull, endBB, notNullBB);
201 EmitBlock(notNullBB);
204 if (sanitizePerformTypeCheck()) {
205 EmitTypeCheck(VBase ? TCK_UpcastToVirtualBase : TCK_Upcast, Loc, Value,
206 DerivedTy, DerivedAlign, true);
209 // Compute the virtual offset.
210 llvm::Value *VirtualOffset = nullptr;
213 CGM.getCXXABI().GetVirtualBaseClassOffset(*this, Value, Derived, VBase);
216 // Apply both offsets.
217 Value = ApplyNonVirtualAndVirtualOffset(*this, Value,
221 // Cast to the destination type.
222 Value = Builder.CreateBitCast(Value, BasePtrTy);
224 // Build a phi if we needed a null check.
225 if (NullCheckValue) {
226 llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
227 Builder.CreateBr(endBB);
230 llvm::PHINode *PHI = Builder.CreatePHI(BasePtrTy, 2, "cast.result");
231 PHI->addIncoming(Value, notNullBB);
232 PHI->addIncoming(llvm::Constant::getNullValue(BasePtrTy), origBB);
240 CodeGenFunction::GetAddressOfDerivedClass(llvm::Value *Value,
241 const CXXRecordDecl *Derived,
242 CastExpr::path_const_iterator PathBegin,
243 CastExpr::path_const_iterator PathEnd,
244 bool NullCheckValue) {
245 assert(PathBegin != PathEnd && "Base path should not be empty!");
248 getContext().getCanonicalType(getContext().getTagDeclType(Derived));
249 llvm::Type *DerivedPtrTy = ConvertType(DerivedTy)->getPointerTo();
251 llvm::Value *NonVirtualOffset =
252 CGM.GetNonVirtualBaseClassOffset(Derived, PathBegin, PathEnd);
254 if (!NonVirtualOffset) {
255 // No offset, we can just cast back.
256 return Builder.CreateBitCast(Value, DerivedPtrTy);
259 llvm::BasicBlock *CastNull = nullptr;
260 llvm::BasicBlock *CastNotNull = nullptr;
261 llvm::BasicBlock *CastEnd = nullptr;
263 if (NullCheckValue) {
264 CastNull = createBasicBlock("cast.null");
265 CastNotNull = createBasicBlock("cast.notnull");
266 CastEnd = createBasicBlock("cast.end");
268 llvm::Value *IsNull = Builder.CreateIsNull(Value);
269 Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
270 EmitBlock(CastNotNull);
274 Value = Builder.CreateBitCast(Value, Int8PtrTy);
275 Value = Builder.CreateGEP(Value, Builder.CreateNeg(NonVirtualOffset),
279 Value = Builder.CreateBitCast(Value, DerivedPtrTy);
281 if (NullCheckValue) {
282 Builder.CreateBr(CastEnd);
284 Builder.CreateBr(CastEnd);
287 llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
288 PHI->addIncoming(Value, CastNotNull);
289 PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()),
297 llvm::Value *CodeGenFunction::GetVTTParameter(GlobalDecl GD,
300 if (!CGM.getCXXABI().NeedsVTTParameter(GD)) {
301 // This constructor/destructor does not need a VTT parameter.
305 const CXXRecordDecl *RD = cast<CXXMethodDecl>(CurCodeDecl)->getParent();
306 const CXXRecordDecl *Base = cast<CXXMethodDecl>(GD.getDecl())->getParent();
310 uint64_t SubVTTIndex;
313 // If this is a delegating constructor call, just load the VTT.
315 } else if (RD == Base) {
316 // If the record matches the base, this is the complete ctor/dtor
317 // variant calling the base variant in a class with virtual bases.
318 assert(!CGM.getCXXABI().NeedsVTTParameter(CurGD) &&
319 "doing no-op VTT offset in base dtor/ctor?");
320 assert(!ForVirtualBase && "Can't have same class as virtual base!");
323 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
324 CharUnits BaseOffset = ForVirtualBase ?
325 Layout.getVBaseClassOffset(Base) :
326 Layout.getBaseClassOffset(Base);
329 CGM.getVTables().getSubVTTIndex(RD, BaseSubobject(Base, BaseOffset));
330 assert(SubVTTIndex != 0 && "Sub-VTT index must be greater than zero!");
333 if (CGM.getCXXABI().NeedsVTTParameter(CurGD)) {
334 // A VTT parameter was passed to the constructor, use it.
336 VTT = Builder.CreateConstInBoundsGEP1_64(VTT, SubVTTIndex);
338 // We're the complete constructor, so get the VTT by name.
339 VTT = CGM.getVTables().GetAddrOfVTT(RD);
340 VTT = Builder.CreateConstInBoundsGEP2_64(VTT, 0, SubVTTIndex);
347 /// Call the destructor for a direct base class.
348 struct CallBaseDtor : EHScopeStack::Cleanup {
349 const CXXRecordDecl *BaseClass;
351 CallBaseDtor(const CXXRecordDecl *Base, bool BaseIsVirtual)
352 : BaseClass(Base), BaseIsVirtual(BaseIsVirtual) {}
354 void Emit(CodeGenFunction &CGF, Flags flags) override {
355 const CXXRecordDecl *DerivedClass =
356 cast<CXXMethodDecl>(CGF.CurCodeDecl)->getParent();
358 const CXXDestructorDecl *D = BaseClass->getDestructor();
360 CGF.GetAddressOfDirectBaseInCompleteClass(CGF.LoadCXXThis(),
361 DerivedClass, BaseClass,
363 CGF.EmitCXXDestructorCall(D, Dtor_Base, BaseIsVirtual,
364 /*Delegating=*/false, Addr);
368 /// A visitor which checks whether an initializer uses 'this' in a
369 /// way which requires the vtable to be properly set.
370 struct DynamicThisUseChecker : ConstEvaluatedExprVisitor<DynamicThisUseChecker> {
371 typedef ConstEvaluatedExprVisitor<DynamicThisUseChecker> super;
375 DynamicThisUseChecker(const ASTContext &C) : super(C), UsesThis(false) {}
377 // Black-list all explicit and implicit references to 'this'.
379 // Do we need to worry about external references to 'this' derived
380 // from arbitrary code? If so, then anything which runs arbitrary
381 // external code might potentially access the vtable.
382 void VisitCXXThisExpr(const CXXThisExpr *E) { UsesThis = true; }
386 static bool BaseInitializerUsesThis(ASTContext &C, const Expr *Init) {
387 DynamicThisUseChecker Checker(C);
389 return Checker.UsesThis;
392 static void EmitBaseInitializer(CodeGenFunction &CGF,
393 const CXXRecordDecl *ClassDecl,
394 CXXCtorInitializer *BaseInit,
395 CXXCtorType CtorType) {
396 assert(BaseInit->isBaseInitializer() &&
397 "Must have base initializer!");
399 llvm::Value *ThisPtr = CGF.LoadCXXThis();
401 const Type *BaseType = BaseInit->getBaseClass();
402 CXXRecordDecl *BaseClassDecl =
403 cast<CXXRecordDecl>(BaseType->getAs<RecordType>()->getDecl());
405 bool isBaseVirtual = BaseInit->isBaseVirtual();
407 // The base constructor doesn't construct virtual bases.
408 if (CtorType == Ctor_Base && isBaseVirtual)
411 // If the initializer for the base (other than the constructor
412 // itself) accesses 'this' in any way, we need to initialize the
414 if (BaseInitializerUsesThis(CGF.getContext(), BaseInit->getInit()))
415 CGF.InitializeVTablePointers(ClassDecl);
417 // We can pretend to be a complete class because it only matters for
418 // virtual bases, and we only do virtual bases for complete ctors.
420 CGF.GetAddressOfDirectBaseInCompleteClass(ThisPtr, ClassDecl,
423 CharUnits Alignment = CGF.getContext().getTypeAlignInChars(BaseType);
424 AggValueSlot AggSlot =
425 AggValueSlot::forAddr(V, Alignment, Qualifiers(),
426 AggValueSlot::IsDestructed,
427 AggValueSlot::DoesNotNeedGCBarriers,
428 AggValueSlot::IsNotAliased);
430 CGF.EmitAggExpr(BaseInit->getInit(), AggSlot);
432 if (CGF.CGM.getLangOpts().Exceptions &&
433 !BaseClassDecl->hasTrivialDestructor())
434 CGF.EHStack.pushCleanup<CallBaseDtor>(EHCleanup, BaseClassDecl,
438 static void EmitAggMemberInitializer(CodeGenFunction &CGF,
441 llvm::Value *ArrayIndexVar,
443 ArrayRef<VarDecl *> ArrayIndexes,
445 if (Index == ArrayIndexes.size()) {
449 // If we have an array index variable, load it and use it as an offset.
450 // Then, increment the value.
451 llvm::Value *Dest = LHS.getAddress();
452 llvm::Value *ArrayIndex = CGF.Builder.CreateLoad(ArrayIndexVar);
453 Dest = CGF.Builder.CreateInBoundsGEP(Dest, ArrayIndex, "destaddress");
454 llvm::Value *Next = llvm::ConstantInt::get(ArrayIndex->getType(), 1);
455 Next = CGF.Builder.CreateAdd(ArrayIndex, Next, "inc");
456 CGF.Builder.CreateStore(Next, ArrayIndexVar);
458 // Update the LValue.
460 CharUnits Align = CGF.getContext().getTypeAlignInChars(T);
461 LV.setAlignment(std::min(Align, LV.getAlignment()));
464 switch (CGF.getEvaluationKind(T)) {
466 CGF.EmitScalarInit(Init, /*decl*/ nullptr, LV, false);
469 CGF.EmitComplexExprIntoLValue(Init, LV, /*isInit*/ true);
471 case TEK_Aggregate: {
473 AggValueSlot::forLValue(LV,
474 AggValueSlot::IsDestructed,
475 AggValueSlot::DoesNotNeedGCBarriers,
476 AggValueSlot::IsNotAliased);
478 CGF.EmitAggExpr(Init, Slot);
486 const ConstantArrayType *Array = CGF.getContext().getAsConstantArrayType(T);
487 assert(Array && "Array initialization without the array type?");
488 llvm::Value *IndexVar
489 = CGF.GetAddrOfLocalVar(ArrayIndexes[Index]);
490 assert(IndexVar && "Array index variable not loaded");
492 // Initialize this index variable to zero.
494 = llvm::Constant::getNullValue(
495 CGF.ConvertType(CGF.getContext().getSizeType()));
496 CGF.Builder.CreateStore(Zero, IndexVar);
498 // Start the loop with a block that tests the condition.
499 llvm::BasicBlock *CondBlock = CGF.createBasicBlock("for.cond");
500 llvm::BasicBlock *AfterFor = CGF.createBasicBlock("for.end");
502 CGF.EmitBlock(CondBlock);
504 llvm::BasicBlock *ForBody = CGF.createBasicBlock("for.body");
505 // Generate: if (loop-index < number-of-elements) fall to the loop body,
506 // otherwise, go to the block after the for-loop.
507 uint64_t NumElements = Array->getSize().getZExtValue();
508 llvm::Value *Counter = CGF.Builder.CreateLoad(IndexVar);
509 llvm::Value *NumElementsPtr =
510 llvm::ConstantInt::get(Counter->getType(), NumElements);
511 llvm::Value *IsLess = CGF.Builder.CreateICmpULT(Counter, NumElementsPtr,
514 // If the condition is true, execute the body.
515 CGF.Builder.CreateCondBr(IsLess, ForBody, AfterFor);
517 CGF.EmitBlock(ForBody);
518 llvm::BasicBlock *ContinueBlock = CGF.createBasicBlock("for.inc");
520 // Inside the loop body recurse to emit the inner loop or, eventually, the
522 EmitAggMemberInitializer(CGF, LHS, Init, ArrayIndexVar,
523 Array->getElementType(), ArrayIndexes, Index + 1);
525 CGF.EmitBlock(ContinueBlock);
527 // Emit the increment of the loop counter.
528 llvm::Value *NextVal = llvm::ConstantInt::get(Counter->getType(), 1);
529 Counter = CGF.Builder.CreateLoad(IndexVar);
530 NextVal = CGF.Builder.CreateAdd(Counter, NextVal, "inc");
531 CGF.Builder.CreateStore(NextVal, IndexVar);
533 // Finally, branch back up to the condition for the next iteration.
534 CGF.EmitBranch(CondBlock);
536 // Emit the fall-through block.
537 CGF.EmitBlock(AfterFor, true);
540 static bool isMemcpyEquivalentSpecialMember(const CXXMethodDecl *D) {
541 auto *CD = dyn_cast<CXXConstructorDecl>(D);
542 if (!(CD && CD->isCopyOrMoveConstructor()) &&
543 !D->isCopyAssignmentOperator() && !D->isMoveAssignmentOperator())
546 // We can emit a memcpy for a trivial copy or move constructor/assignment.
547 if (D->isTrivial() && !D->getParent()->mayInsertExtraPadding())
550 // We *must* emit a memcpy for a defaulted union copy or move op.
551 if (D->getParent()->isUnion() && D->isDefaulted())
557 static void EmitLValueForAnyFieldInitialization(CodeGenFunction &CGF,
558 CXXCtorInitializer *MemberInit,
560 FieldDecl *Field = MemberInit->getAnyMember();
561 if (MemberInit->isIndirectMemberInitializer()) {
562 // If we are initializing an anonymous union field, drill down to the field.
563 IndirectFieldDecl *IndirectField = MemberInit->getIndirectMember();
564 for (const auto *I : IndirectField->chain())
565 LHS = CGF.EmitLValueForFieldInitialization(LHS, cast<FieldDecl>(I));
567 LHS = CGF.EmitLValueForFieldInitialization(LHS, Field);
571 static void EmitMemberInitializer(CodeGenFunction &CGF,
572 const CXXRecordDecl *ClassDecl,
573 CXXCtorInitializer *MemberInit,
574 const CXXConstructorDecl *Constructor,
575 FunctionArgList &Args) {
576 ApplyDebugLocation Loc(CGF, MemberInit->getSourceLocation());
577 assert(MemberInit->isAnyMemberInitializer() &&
578 "Must have member initializer!");
579 assert(MemberInit->getInit() && "Must have initializer!");
581 // non-static data member initializers.
582 FieldDecl *Field = MemberInit->getAnyMember();
583 QualType FieldType = Field->getType();
585 llvm::Value *ThisPtr = CGF.LoadCXXThis();
586 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
587 LValue LHS = CGF.MakeNaturalAlignAddrLValue(ThisPtr, RecordTy);
589 EmitLValueForAnyFieldInitialization(CGF, MemberInit, LHS);
591 // Special case: if we are in a copy or move constructor, and we are copying
592 // an array of PODs or classes with trivial copy constructors, ignore the
593 // AST and perform the copy we know is equivalent.
594 // FIXME: This is hacky at best... if we had a bit more explicit information
595 // in the AST, we could generalize it more easily.
596 const ConstantArrayType *Array
597 = CGF.getContext().getAsConstantArrayType(FieldType);
598 if (Array && Constructor->isDefaulted() &&
599 Constructor->isCopyOrMoveConstructor()) {
600 QualType BaseElementTy = CGF.getContext().getBaseElementType(Array);
601 CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit());
602 if (BaseElementTy.isPODType(CGF.getContext()) ||
603 (CE && isMemcpyEquivalentSpecialMember(CE->getConstructor()))) {
604 unsigned SrcArgIndex =
605 CGF.CGM.getCXXABI().getSrcArgforCopyCtor(Constructor, Args);
607 = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(Args[SrcArgIndex]));
608 LValue ThisRHSLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy);
609 LValue Src = CGF.EmitLValueForFieldInitialization(ThisRHSLV, Field);
611 // Copy the aggregate.
612 CGF.EmitAggregateCopy(LHS.getAddress(), Src.getAddress(), FieldType,
613 LHS.isVolatileQualified());
614 // Ensure that we destroy the objects if an exception is thrown later in
616 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
617 if (CGF.needsEHCleanup(dtorKind))
618 CGF.pushEHDestroy(dtorKind, LHS.getAddress(), FieldType);
623 ArrayRef<VarDecl *> ArrayIndexes;
624 if (MemberInit->getNumArrayIndices())
625 ArrayIndexes = MemberInit->getArrayIndexes();
626 CGF.EmitInitializerForField(Field, LHS, MemberInit->getInit(), ArrayIndexes);
629 void CodeGenFunction::EmitInitializerForField(
630 FieldDecl *Field, LValue LHS, Expr *Init,
631 ArrayRef<VarDecl *> ArrayIndexes) {
632 QualType FieldType = Field->getType();
633 switch (getEvaluationKind(FieldType)) {
635 if (LHS.isSimple()) {
636 EmitExprAsInit(Init, Field, LHS, false);
638 RValue RHS = RValue::get(EmitScalarExpr(Init));
639 EmitStoreThroughLValue(RHS, LHS);
643 EmitComplexExprIntoLValue(Init, LHS, /*isInit*/ true);
645 case TEK_Aggregate: {
646 llvm::Value *ArrayIndexVar = nullptr;
647 if (ArrayIndexes.size()) {
648 llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
650 // The LHS is a pointer to the first object we'll be constructing, as
652 QualType BaseElementTy = getContext().getBaseElementType(FieldType);
653 llvm::Type *BasePtr = ConvertType(BaseElementTy);
654 BasePtr = llvm::PointerType::getUnqual(BasePtr);
655 llvm::Value *BaseAddrPtr = Builder.CreateBitCast(LHS.getAddress(),
657 LHS = MakeAddrLValue(BaseAddrPtr, BaseElementTy);
659 // Create an array index that will be used to walk over all of the
660 // objects we're constructing.
661 ArrayIndexVar = CreateTempAlloca(SizeTy, "object.index");
662 llvm::Value *Zero = llvm::Constant::getNullValue(SizeTy);
663 Builder.CreateStore(Zero, ArrayIndexVar);
666 // Emit the block variables for the array indices, if any.
667 for (unsigned I = 0, N = ArrayIndexes.size(); I != N; ++I)
668 EmitAutoVarDecl(*ArrayIndexes[I]);
671 EmitAggMemberInitializer(*this, LHS, Init, ArrayIndexVar, FieldType,
676 // Ensure that we destroy this object if an exception is thrown
677 // later in the constructor.
678 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
679 if (needsEHCleanup(dtorKind))
680 pushEHDestroy(dtorKind, LHS.getAddress(), FieldType);
683 /// Checks whether the given constructor is a valid subject for the
684 /// complete-to-base constructor delegation optimization, i.e.
685 /// emitting the complete constructor as a simple call to the base
687 static bool IsConstructorDelegationValid(const CXXConstructorDecl *Ctor) {
689 // Currently we disable the optimization for classes with virtual
690 // bases because (1) the addresses of parameter variables need to be
691 // consistent across all initializers but (2) the delegate function
692 // call necessarily creates a second copy of the parameter variable.
694 // The limiting example (purely theoretical AFAIK):
695 // struct A { A(int &c) { c++; } };
696 // struct B : virtual A {
697 // B(int count) : A(count) { printf("%d\n", count); }
699 // ...although even this example could in principle be emitted as a
700 // delegation since the address of the parameter doesn't escape.
701 if (Ctor->getParent()->getNumVBases()) {
702 // TODO: white-list trivial vbase initializers. This case wouldn't
703 // be subject to the restrictions below.
705 // TODO: white-list cases where:
706 // - there are no non-reference parameters to the constructor
707 // - the initializers don't access any non-reference parameters
708 // - the initializers don't take the address of non-reference
711 // If we ever add any of the above cases, remember that:
712 // - function-try-blocks will always blacklist this optimization
713 // - we need to perform the constructor prologue and cleanup in
714 // EmitConstructorBody.
719 // We also disable the optimization for variadic functions because
720 // it's impossible to "re-pass" varargs.
721 if (Ctor->getType()->getAs<FunctionProtoType>()->isVariadic())
724 // FIXME: Decide if we can do a delegation of a delegating constructor.
725 if (Ctor->isDelegatingConstructor())
731 // Emit code in ctor (Prologue==true) or dtor (Prologue==false)
732 // to poison the extra field paddings inserted under
733 // -fsanitize-address-field-padding=1|2.
734 void CodeGenFunction::EmitAsanPrologueOrEpilogue(bool Prologue) {
735 ASTContext &Context = getContext();
736 const CXXRecordDecl *ClassDecl =
737 Prologue ? cast<CXXConstructorDecl>(CurGD.getDecl())->getParent()
738 : cast<CXXDestructorDecl>(CurGD.getDecl())->getParent();
739 if (!ClassDecl->mayInsertExtraPadding()) return;
741 struct SizeAndOffset {
746 unsigned PtrSize = CGM.getDataLayout().getPointerSizeInBits();
747 const ASTRecordLayout &Info = Context.getASTRecordLayout(ClassDecl);
749 // Populate sizes and offsets of fields.
750 SmallVector<SizeAndOffset, 16> SSV(Info.getFieldCount());
751 for (unsigned i = 0, e = Info.getFieldCount(); i != e; ++i)
753 Context.toCharUnitsFromBits(Info.getFieldOffset(i)).getQuantity();
755 size_t NumFields = 0;
756 for (const auto *Field : ClassDecl->fields()) {
757 const FieldDecl *D = Field;
758 std::pair<CharUnits, CharUnits> FieldInfo =
759 Context.getTypeInfoInChars(D->getType());
760 CharUnits FieldSize = FieldInfo.first;
761 assert(NumFields < SSV.size());
762 SSV[NumFields].Size = D->isBitField() ? 0 : FieldSize.getQuantity();
765 assert(NumFields == SSV.size());
766 if (SSV.size() <= 1) return;
768 // We will insert calls to __asan_* run-time functions.
769 // LLVM AddressSanitizer pass may decide to inline them later.
770 llvm::Type *Args[2] = {IntPtrTy, IntPtrTy};
771 llvm::FunctionType *FTy =
772 llvm::FunctionType::get(CGM.VoidTy, Args, false);
773 llvm::Constant *F = CGM.CreateRuntimeFunction(
774 FTy, Prologue ? "__asan_poison_intra_object_redzone"
775 : "__asan_unpoison_intra_object_redzone");
777 llvm::Value *ThisPtr = LoadCXXThis();
778 ThisPtr = Builder.CreatePtrToInt(ThisPtr, IntPtrTy);
779 uint64_t TypeSize = Info.getNonVirtualSize().getQuantity();
780 // For each field check if it has sufficient padding,
781 // if so (un)poison it with a call.
782 for (size_t i = 0; i < SSV.size(); i++) {
783 uint64_t AsanAlignment = 8;
784 uint64_t NextField = i == SSV.size() - 1 ? TypeSize : SSV[i + 1].Offset;
785 uint64_t PoisonSize = NextField - SSV[i].Offset - SSV[i].Size;
786 uint64_t EndOffset = SSV[i].Offset + SSV[i].Size;
787 if (PoisonSize < AsanAlignment || !SSV[i].Size ||
788 (NextField % AsanAlignment) != 0)
791 F, {Builder.CreateAdd(ThisPtr, Builder.getIntN(PtrSize, EndOffset)),
792 Builder.getIntN(PtrSize, PoisonSize)});
796 /// EmitConstructorBody - Emits the body of the current constructor.
797 void CodeGenFunction::EmitConstructorBody(FunctionArgList &Args) {
798 EmitAsanPrologueOrEpilogue(true);
799 const CXXConstructorDecl *Ctor = cast<CXXConstructorDecl>(CurGD.getDecl());
800 CXXCtorType CtorType = CurGD.getCtorType();
802 assert((CGM.getTarget().getCXXABI().hasConstructorVariants() ||
803 CtorType == Ctor_Complete) &&
804 "can only generate complete ctor for this ABI");
806 // Before we go any further, try the complete->base constructor
807 // delegation optimization.
808 if (CtorType == Ctor_Complete && IsConstructorDelegationValid(Ctor) &&
809 CGM.getTarget().getCXXABI().hasConstructorVariants()) {
810 EmitDelegateCXXConstructorCall(Ctor, Ctor_Base, Args, Ctor->getLocEnd());
814 const FunctionDecl *Definition = 0;
815 Stmt *Body = Ctor->getBody(Definition);
816 assert(Definition == Ctor && "emitting wrong constructor body");
818 // Enter the function-try-block before the constructor prologue if
820 bool IsTryBody = (Body && isa<CXXTryStmt>(Body));
822 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
824 incrementProfileCounter(Body);
826 RunCleanupsScope RunCleanups(*this);
828 // TODO: in restricted cases, we can emit the vbase initializers of
829 // a complete ctor and then delegate to the base ctor.
831 // Emit the constructor prologue, i.e. the base and member
833 EmitCtorPrologue(Ctor, CtorType, Args);
835 // Emit the body of the statement.
837 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
841 // Emit any cleanup blocks associated with the member or base
842 // initializers, which includes (along the exceptional path) the
843 // destructors for those members and bases that were fully
845 RunCleanups.ForceCleanup();
848 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
852 /// RAII object to indicate that codegen is copying the value representation
853 /// instead of the object representation. Useful when copying a struct or
854 /// class which has uninitialized members and we're only performing
855 /// lvalue-to-rvalue conversion on the object but not its members.
856 class CopyingValueRepresentation {
858 explicit CopyingValueRepresentation(CodeGenFunction &CGF)
859 : CGF(CGF), OldSanOpts(CGF.SanOpts) {
860 CGF.SanOpts.set(SanitizerKind::Bool, false);
861 CGF.SanOpts.set(SanitizerKind::Enum, false);
863 ~CopyingValueRepresentation() {
864 CGF.SanOpts = OldSanOpts;
867 CodeGenFunction &CGF;
868 SanitizerSet OldSanOpts;
873 class FieldMemcpyizer {
875 FieldMemcpyizer(CodeGenFunction &CGF, const CXXRecordDecl *ClassDecl,
876 const VarDecl *SrcRec)
877 : CGF(CGF), ClassDecl(ClassDecl), SrcRec(SrcRec),
878 RecLayout(CGF.getContext().getASTRecordLayout(ClassDecl)),
879 FirstField(nullptr), LastField(nullptr), FirstFieldOffset(0),
880 LastFieldOffset(0), LastAddedFieldIndex(0) {}
882 bool isMemcpyableField(FieldDecl *F) const {
883 // Never memcpy fields when we are adding poisoned paddings.
884 if (CGF.getContext().getLangOpts().SanitizeAddressFieldPadding)
886 Qualifiers Qual = F->getType().getQualifiers();
887 if (Qual.hasVolatile() || Qual.hasObjCLifetime())
892 void addMemcpyableField(FieldDecl *F) {
899 CharUnits getMemcpySize(uint64_t FirstByteOffset) const {
900 unsigned LastFieldSize =
901 LastField->isBitField() ?
902 LastField->getBitWidthValue(CGF.getContext()) :
903 CGF.getContext().getTypeSize(LastField->getType());
904 uint64_t MemcpySizeBits =
905 LastFieldOffset + LastFieldSize - FirstByteOffset +
906 CGF.getContext().getCharWidth() - 1;
907 CharUnits MemcpySize =
908 CGF.getContext().toCharUnitsFromBits(MemcpySizeBits);
913 // Give the subclass a chance to bail out if it feels the memcpy isn't
914 // worth it (e.g. Hasn't aggregated enough data).
919 uint64_t FirstByteOffset;
920 if (FirstField->isBitField()) {
921 const CGRecordLayout &RL =
922 CGF.getTypes().getCGRecordLayout(FirstField->getParent());
923 const CGBitFieldInfo &BFInfo = RL.getBitFieldInfo(FirstField);
924 // FirstFieldOffset is not appropriate for bitfields,
925 // we need to use the storage offset instead.
926 FirstByteOffset = CGF.getContext().toBits(BFInfo.StorageOffset);
928 FirstByteOffset = FirstFieldOffset;
931 CharUnits MemcpySize = getMemcpySize(FirstByteOffset);
932 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
933 llvm::Value *ThisPtr = CGF.LoadCXXThis();
934 LValue DestLV = CGF.MakeNaturalAlignAddrLValue(ThisPtr, RecordTy);
935 LValue Dest = CGF.EmitLValueForFieldInitialization(DestLV, FirstField);
936 llvm::Value *SrcPtr = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(SrcRec));
937 LValue SrcLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy);
938 LValue Src = CGF.EmitLValueForFieldInitialization(SrcLV, FirstField);
940 CharUnits Offset = CGF.getContext().toCharUnitsFromBits(FirstByteOffset);
941 CharUnits Alignment = DestLV.getAlignment().alignmentAtOffset(Offset);
943 emitMemcpyIR(Dest.isBitField() ? Dest.getBitFieldAddr() : Dest.getAddress(),
944 Src.isBitField() ? Src.getBitFieldAddr() : Src.getAddress(),
945 MemcpySize, Alignment);
950 FirstField = nullptr;
954 CodeGenFunction &CGF;
955 const CXXRecordDecl *ClassDecl;
959 void emitMemcpyIR(llvm::Value *DestPtr, llvm::Value *SrcPtr,
960 CharUnits Size, CharUnits Alignment) {
961 llvm::PointerType *DPT = cast<llvm::PointerType>(DestPtr->getType());
963 llvm::Type::getInt8PtrTy(CGF.getLLVMContext(), DPT->getAddressSpace());
964 DestPtr = CGF.Builder.CreateBitCast(DestPtr, DBP);
966 llvm::PointerType *SPT = cast<llvm::PointerType>(SrcPtr->getType());
968 llvm::Type::getInt8PtrTy(CGF.getLLVMContext(), SPT->getAddressSpace());
969 SrcPtr = CGF.Builder.CreateBitCast(SrcPtr, SBP);
971 CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, Size.getQuantity(),
972 Alignment.getQuantity());
975 void addInitialField(FieldDecl *F) {
978 FirstFieldOffset = RecLayout.getFieldOffset(F->getFieldIndex());
979 LastFieldOffset = FirstFieldOffset;
980 LastAddedFieldIndex = F->getFieldIndex();
984 void addNextField(FieldDecl *F) {
985 // For the most part, the following invariant will hold:
986 // F->getFieldIndex() == LastAddedFieldIndex + 1
987 // The one exception is that Sema won't add a copy-initializer for an
988 // unnamed bitfield, which will show up here as a gap in the sequence.
989 assert(F->getFieldIndex() >= LastAddedFieldIndex + 1 &&
990 "Cannot aggregate fields out of order.");
991 LastAddedFieldIndex = F->getFieldIndex();
993 // The 'first' and 'last' fields are chosen by offset, rather than field
994 // index. This allows the code to support bitfields, as well as regular
996 uint64_t FOffset = RecLayout.getFieldOffset(F->getFieldIndex());
997 if (FOffset < FirstFieldOffset) {
999 FirstFieldOffset = FOffset;
1000 } else if (FOffset > LastFieldOffset) {
1002 LastFieldOffset = FOffset;
1006 const VarDecl *SrcRec;
1007 const ASTRecordLayout &RecLayout;
1008 FieldDecl *FirstField;
1009 FieldDecl *LastField;
1010 uint64_t FirstFieldOffset, LastFieldOffset;
1011 unsigned LastAddedFieldIndex;
1014 class ConstructorMemcpyizer : public FieldMemcpyizer {
1017 /// Get source argument for copy constructor. Returns null if not a copy
1019 static const VarDecl *getTrivialCopySource(CodeGenFunction &CGF,
1020 const CXXConstructorDecl *CD,
1021 FunctionArgList &Args) {
1022 if (CD->isCopyOrMoveConstructor() && CD->isDefaulted())
1023 return Args[CGF.CGM.getCXXABI().getSrcArgforCopyCtor(CD, Args)];
1027 // Returns true if a CXXCtorInitializer represents a member initialization
1028 // that can be rolled into a memcpy.
1029 bool isMemberInitMemcpyable(CXXCtorInitializer *MemberInit) const {
1030 if (!MemcpyableCtor)
1032 FieldDecl *Field = MemberInit->getMember();
1033 assert(Field && "No field for member init.");
1034 QualType FieldType = Field->getType();
1035 CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit());
1037 // Bail out on non-memcpyable, not-trivially-copyable members.
1038 if (!(CE && isMemcpyEquivalentSpecialMember(CE->getConstructor())) &&
1039 !(FieldType.isTriviallyCopyableType(CGF.getContext()) ||
1040 FieldType->isReferenceType()))
1043 // Bail out on volatile fields.
1044 if (!isMemcpyableField(Field))
1047 // Otherwise we're good.
1052 ConstructorMemcpyizer(CodeGenFunction &CGF, const CXXConstructorDecl *CD,
1053 FunctionArgList &Args)
1054 : FieldMemcpyizer(CGF, CD->getParent(), getTrivialCopySource(CGF, CD, Args)),
1055 ConstructorDecl(CD),
1056 MemcpyableCtor(CD->isDefaulted() &&
1057 CD->isCopyOrMoveConstructor() &&
1058 CGF.getLangOpts().getGC() == LangOptions::NonGC),
1061 void addMemberInitializer(CXXCtorInitializer *MemberInit) {
1062 if (isMemberInitMemcpyable(MemberInit)) {
1063 AggregatedInits.push_back(MemberInit);
1064 addMemcpyableField(MemberInit->getMember());
1066 emitAggregatedInits();
1067 EmitMemberInitializer(CGF, ConstructorDecl->getParent(), MemberInit,
1068 ConstructorDecl, Args);
1072 void emitAggregatedInits() {
1073 if (AggregatedInits.size() <= 1) {
1074 // This memcpy is too small to be worthwhile. Fall back on default
1076 if (!AggregatedInits.empty()) {
1077 CopyingValueRepresentation CVR(CGF);
1078 EmitMemberInitializer(CGF, ConstructorDecl->getParent(),
1079 AggregatedInits[0], ConstructorDecl, Args);
1080 AggregatedInits.clear();
1086 pushEHDestructors();
1088 AggregatedInits.clear();
1091 void pushEHDestructors() {
1092 llvm::Value *ThisPtr = CGF.LoadCXXThis();
1093 QualType RecordTy = CGF.getContext().getTypeDeclType(ClassDecl);
1094 LValue LHS = CGF.MakeNaturalAlignAddrLValue(ThisPtr, RecordTy);
1096 for (unsigned i = 0; i < AggregatedInits.size(); ++i) {
1097 CXXCtorInitializer *MemberInit = AggregatedInits[i];
1098 QualType FieldType = MemberInit->getAnyMember()->getType();
1099 QualType::DestructionKind dtorKind = FieldType.isDestructedType();
1100 if (!CGF.needsEHCleanup(dtorKind))
1102 LValue FieldLHS = LHS;
1103 EmitLValueForAnyFieldInitialization(CGF, MemberInit, FieldLHS);
1104 CGF.pushEHDestroy(dtorKind, FieldLHS.getAddress(), FieldType);
1109 emitAggregatedInits();
1113 const CXXConstructorDecl *ConstructorDecl;
1114 bool MemcpyableCtor;
1115 FunctionArgList &Args;
1116 SmallVector<CXXCtorInitializer*, 16> AggregatedInits;
1119 class AssignmentMemcpyizer : public FieldMemcpyizer {
1122 // Returns the memcpyable field copied by the given statement, if one
1123 // exists. Otherwise returns null.
1124 FieldDecl *getMemcpyableField(Stmt *S) {
1125 if (!AssignmentsMemcpyable)
1127 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(S)) {
1128 // Recognise trivial assignments.
1129 if (BO->getOpcode() != BO_Assign)
1131 MemberExpr *ME = dyn_cast<MemberExpr>(BO->getLHS());
1134 FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl());
1135 if (!Field || !isMemcpyableField(Field))
1137 Stmt *RHS = BO->getRHS();
1138 if (ImplicitCastExpr *EC = dyn_cast<ImplicitCastExpr>(RHS))
1139 RHS = EC->getSubExpr();
1142 MemberExpr *ME2 = dyn_cast<MemberExpr>(RHS);
1143 if (dyn_cast<FieldDecl>(ME2->getMemberDecl()) != Field)
1146 } else if (CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(S)) {
1147 CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MCE->getCalleeDecl());
1148 if (!(MD && isMemcpyEquivalentSpecialMember(MD)))
1150 MemberExpr *IOA = dyn_cast<MemberExpr>(MCE->getImplicitObjectArgument());
1153 FieldDecl *Field = dyn_cast<FieldDecl>(IOA->getMemberDecl());
1154 if (!Field || !isMemcpyableField(Field))
1156 MemberExpr *Arg0 = dyn_cast<MemberExpr>(MCE->getArg(0));
1157 if (!Arg0 || Field != dyn_cast<FieldDecl>(Arg0->getMemberDecl()))
1160 } else if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
1161 FunctionDecl *FD = dyn_cast<FunctionDecl>(CE->getCalleeDecl());
1162 if (!FD || FD->getBuiltinID() != Builtin::BI__builtin_memcpy)
1164 Expr *DstPtr = CE->getArg(0);
1165 if (ImplicitCastExpr *DC = dyn_cast<ImplicitCastExpr>(DstPtr))
1166 DstPtr = DC->getSubExpr();
1167 UnaryOperator *DUO = dyn_cast<UnaryOperator>(DstPtr);
1168 if (!DUO || DUO->getOpcode() != UO_AddrOf)
1170 MemberExpr *ME = dyn_cast<MemberExpr>(DUO->getSubExpr());
1173 FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl());
1174 if (!Field || !isMemcpyableField(Field))
1176 Expr *SrcPtr = CE->getArg(1);
1177 if (ImplicitCastExpr *SC = dyn_cast<ImplicitCastExpr>(SrcPtr))
1178 SrcPtr = SC->getSubExpr();
1179 UnaryOperator *SUO = dyn_cast<UnaryOperator>(SrcPtr);
1180 if (!SUO || SUO->getOpcode() != UO_AddrOf)
1182 MemberExpr *ME2 = dyn_cast<MemberExpr>(SUO->getSubExpr());
1183 if (!ME2 || Field != dyn_cast<FieldDecl>(ME2->getMemberDecl()))
1191 bool AssignmentsMemcpyable;
1192 SmallVector<Stmt*, 16> AggregatedStmts;
1196 AssignmentMemcpyizer(CodeGenFunction &CGF, const CXXMethodDecl *AD,
1197 FunctionArgList &Args)
1198 : FieldMemcpyizer(CGF, AD->getParent(), Args[Args.size() - 1]),
1199 AssignmentsMemcpyable(CGF.getLangOpts().getGC() == LangOptions::NonGC) {
1200 assert(Args.size() == 2);
1203 void emitAssignment(Stmt *S) {
1204 FieldDecl *F = getMemcpyableField(S);
1206 addMemcpyableField(F);
1207 AggregatedStmts.push_back(S);
1209 emitAggregatedStmts();
1214 void emitAggregatedStmts() {
1215 if (AggregatedStmts.size() <= 1) {
1216 if (!AggregatedStmts.empty()) {
1217 CopyingValueRepresentation CVR(CGF);
1218 CGF.EmitStmt(AggregatedStmts[0]);
1224 AggregatedStmts.clear();
1228 emitAggregatedStmts();
1234 /// EmitCtorPrologue - This routine generates necessary code to initialize
1235 /// base classes and non-static data members belonging to this constructor.
1236 void CodeGenFunction::EmitCtorPrologue(const CXXConstructorDecl *CD,
1237 CXXCtorType CtorType,
1238 FunctionArgList &Args) {
1239 if (CD->isDelegatingConstructor())
1240 return EmitDelegatingCXXConstructorCall(CD, Args);
1242 const CXXRecordDecl *ClassDecl = CD->getParent();
1244 CXXConstructorDecl::init_const_iterator B = CD->init_begin(),
1247 llvm::BasicBlock *BaseCtorContinueBB = nullptr;
1248 if (ClassDecl->getNumVBases() &&
1249 !CGM.getTarget().getCXXABI().hasConstructorVariants()) {
1250 // The ABIs that don't have constructor variants need to put a branch
1251 // before the virtual base initialization code.
1252 BaseCtorContinueBB =
1253 CGM.getCXXABI().EmitCtorCompleteObjectHandler(*this, ClassDecl);
1254 assert(BaseCtorContinueBB);
1257 // Virtual base initializers first.
1258 for (; B != E && (*B)->isBaseInitializer() && (*B)->isBaseVirtual(); B++) {
1259 EmitBaseInitializer(*this, ClassDecl, *B, CtorType);
1262 if (BaseCtorContinueBB) {
1263 // Complete object handler should continue to the remaining initializers.
1264 Builder.CreateBr(BaseCtorContinueBB);
1265 EmitBlock(BaseCtorContinueBB);
1268 // Then, non-virtual base initializers.
1269 for (; B != E && (*B)->isBaseInitializer(); B++) {
1270 assert(!(*B)->isBaseVirtual());
1271 EmitBaseInitializer(*this, ClassDecl, *B, CtorType);
1274 InitializeVTablePointers(ClassDecl);
1276 // And finally, initialize class members.
1277 FieldConstructionScope FCS(*this, CXXThisValue);
1278 ConstructorMemcpyizer CM(*this, CD, Args);
1279 for (; B != E; B++) {
1280 CXXCtorInitializer *Member = (*B);
1281 assert(!Member->isBaseInitializer());
1282 assert(Member->isAnyMemberInitializer() &&
1283 "Delegating initializer on non-delegating constructor");
1284 CM.addMemberInitializer(Member);
1290 FieldHasTrivialDestructorBody(ASTContext &Context, const FieldDecl *Field);
1293 HasTrivialDestructorBody(ASTContext &Context,
1294 const CXXRecordDecl *BaseClassDecl,
1295 const CXXRecordDecl *MostDerivedClassDecl)
1297 // If the destructor is trivial we don't have to check anything else.
1298 if (BaseClassDecl->hasTrivialDestructor())
1301 if (!BaseClassDecl->getDestructor()->hasTrivialBody())
1305 for (const auto *Field : BaseClassDecl->fields())
1306 if (!FieldHasTrivialDestructorBody(Context, Field))
1309 // Check non-virtual bases.
1310 for (const auto &I : BaseClassDecl->bases()) {
1314 const CXXRecordDecl *NonVirtualBase =
1315 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
1316 if (!HasTrivialDestructorBody(Context, NonVirtualBase,
1317 MostDerivedClassDecl))
1321 if (BaseClassDecl == MostDerivedClassDecl) {
1322 // Check virtual bases.
1323 for (const auto &I : BaseClassDecl->vbases()) {
1324 const CXXRecordDecl *VirtualBase =
1325 cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
1326 if (!HasTrivialDestructorBody(Context, VirtualBase,
1327 MostDerivedClassDecl))
1336 FieldHasTrivialDestructorBody(ASTContext &Context,
1337 const FieldDecl *Field)
1339 QualType FieldBaseElementType = Context.getBaseElementType(Field->getType());
1341 const RecordType *RT = FieldBaseElementType->getAs<RecordType>();
1345 CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
1347 // The destructor for an implicit anonymous union member is never invoked.
1348 if (FieldClassDecl->isUnion() && FieldClassDecl->isAnonymousStructOrUnion())
1351 return HasTrivialDestructorBody(Context, FieldClassDecl, FieldClassDecl);
1354 /// CanSkipVTablePointerInitialization - Check whether we need to initialize
1355 /// any vtable pointers before calling this destructor.
1356 static bool CanSkipVTablePointerInitialization(ASTContext &Context,
1357 const CXXDestructorDecl *Dtor) {
1358 if (!Dtor->hasTrivialBody())
1361 // Check the fields.
1362 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1363 for (const auto *Field : ClassDecl->fields())
1364 if (!FieldHasTrivialDestructorBody(Context, Field))
1370 // Generates function call for handling object poisoning, passing in
1371 // references to 'this' and its size as arguments.
1372 static void EmitDtorSanitizerCallback(CodeGenFunction &CGF,
1373 const CXXDestructorDecl *Dtor) {
1374 const ASTRecordLayout &Layout =
1375 CGF.getContext().getASTRecordLayout(Dtor->getParent());
1377 llvm::Value *Args[] = {
1378 CGF.Builder.CreateBitCast(CGF.LoadCXXThis(), CGF.VoidPtrTy),
1379 llvm::ConstantInt::get(CGF.SizeTy, Layout.getSize().getQuantity())};
1380 llvm::Type *ArgTypes[] = {CGF.VoidPtrTy, CGF.SizeTy};
1382 llvm::FunctionType *FnType =
1383 llvm::FunctionType::get(CGF.VoidTy, ArgTypes, false);
1385 CGF.CGM.CreateRuntimeFunction(FnType, "__sanitizer_dtor_callback");
1386 CGF.EmitNounwindRuntimeCall(Fn, Args);
1389 /// EmitDestructorBody - Emits the body of the current destructor.
1390 void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) {
1391 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CurGD.getDecl());
1392 CXXDtorType DtorType = CurGD.getDtorType();
1394 Stmt *Body = Dtor->getBody();
1396 incrementProfileCounter(Body);
1398 // The call to operator delete in a deleting destructor happens
1399 // outside of the function-try-block, which means it's always
1400 // possible to delegate the destructor body to the complete
1401 // destructor. Do so.
1402 if (DtorType == Dtor_Deleting) {
1403 EnterDtorCleanups(Dtor, Dtor_Deleting);
1404 EmitCXXDestructorCall(Dtor, Dtor_Complete, /*ForVirtualBase=*/false,
1405 /*Delegating=*/false, LoadCXXThis());
1410 // If the body is a function-try-block, enter the try before
1412 bool isTryBody = (Body && isa<CXXTryStmt>(Body));
1414 EnterCXXTryStmt(*cast<CXXTryStmt>(Body), true);
1415 EmitAsanPrologueOrEpilogue(false);
1417 // Enter the epilogue cleanups.
1418 RunCleanupsScope DtorEpilogue(*this);
1420 // If this is the complete variant, just invoke the base variant;
1421 // the epilogue will destruct the virtual bases. But we can't do
1422 // this optimization if the body is a function-try-block, because
1423 // we'd introduce *two* handler blocks. In the Microsoft ABI, we
1424 // always delegate because we might not have a definition in this TU.
1427 llvm_unreachable("not expecting a COMDAT");
1429 case Dtor_Deleting: llvm_unreachable("already handled deleting case");
1432 assert((Body || getTarget().getCXXABI().isMicrosoft()) &&
1433 "can't emit a dtor without a body for non-Microsoft ABIs");
1435 // Enter the cleanup scopes for virtual bases.
1436 EnterDtorCleanups(Dtor, Dtor_Complete);
1439 EmitCXXDestructorCall(Dtor, Dtor_Base, /*ForVirtualBase=*/false,
1440 /*Delegating=*/false, LoadCXXThis());
1443 // Fallthrough: act like we're in the base variant.
1448 // Enter the cleanup scopes for fields and non-virtual bases.
1449 EnterDtorCleanups(Dtor, Dtor_Base);
1451 // Initialize the vtable pointers before entering the body.
1452 if (!CanSkipVTablePointerInitialization(getContext(), Dtor))
1453 InitializeVTablePointers(Dtor->getParent());
1456 EmitStmt(cast<CXXTryStmt>(Body)->getTryBlock());
1460 assert(Dtor->isImplicit() && "bodyless dtor not implicit");
1461 // nothing to do besides what's in the epilogue
1463 // -fapple-kext must inline any call to this dtor into
1464 // the caller's body.
1465 if (getLangOpts().AppleKext)
1466 CurFn->addFnAttr(llvm::Attribute::AlwaysInline);
1470 // Jump out through the epilogue cleanups.
1471 DtorEpilogue.ForceCleanup();
1473 // Exit the try if applicable.
1475 ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
1477 // Insert memory-poisoning instrumentation.
1478 if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor)
1479 EmitDtorSanitizerCallback(*this, Dtor);
1482 void CodeGenFunction::emitImplicitAssignmentOperatorBody(FunctionArgList &Args) {
1483 const CXXMethodDecl *AssignOp = cast<CXXMethodDecl>(CurGD.getDecl());
1484 const Stmt *RootS = AssignOp->getBody();
1485 assert(isa<CompoundStmt>(RootS) &&
1486 "Body of an implicit assignment operator should be compound stmt.");
1487 const CompoundStmt *RootCS = cast<CompoundStmt>(RootS);
1489 LexicalScope Scope(*this, RootCS->getSourceRange());
1491 AssignmentMemcpyizer AM(*this, AssignOp, Args);
1492 for (auto *I : RootCS->body())
1493 AM.emitAssignment(I);
1498 /// Call the operator delete associated with the current destructor.
1499 struct CallDtorDelete : EHScopeStack::Cleanup {
1502 void Emit(CodeGenFunction &CGF, Flags flags) override {
1503 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
1504 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1505 CGF.EmitDeleteCall(Dtor->getOperatorDelete(), CGF.LoadCXXThis(),
1506 CGF.getContext().getTagDeclType(ClassDecl));
1510 struct CallDtorDeleteConditional : EHScopeStack::Cleanup {
1511 llvm::Value *ShouldDeleteCondition;
1513 CallDtorDeleteConditional(llvm::Value *ShouldDeleteCondition)
1514 : ShouldDeleteCondition(ShouldDeleteCondition) {
1515 assert(ShouldDeleteCondition != nullptr);
1518 void Emit(CodeGenFunction &CGF, Flags flags) override {
1519 llvm::BasicBlock *callDeleteBB = CGF.createBasicBlock("dtor.call_delete");
1520 llvm::BasicBlock *continueBB = CGF.createBasicBlock("dtor.continue");
1521 llvm::Value *ShouldCallDelete
1522 = CGF.Builder.CreateIsNull(ShouldDeleteCondition);
1523 CGF.Builder.CreateCondBr(ShouldCallDelete, continueBB, callDeleteBB);
1525 CGF.EmitBlock(callDeleteBB);
1526 const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CGF.CurCodeDecl);
1527 const CXXRecordDecl *ClassDecl = Dtor->getParent();
1528 CGF.EmitDeleteCall(Dtor->getOperatorDelete(), CGF.LoadCXXThis(),
1529 CGF.getContext().getTagDeclType(ClassDecl));
1530 CGF.Builder.CreateBr(continueBB);
1532 CGF.EmitBlock(continueBB);
1536 class DestroyField : public EHScopeStack::Cleanup {
1537 const FieldDecl *field;
1538 CodeGenFunction::Destroyer *destroyer;
1539 bool useEHCleanupForArray;
1542 DestroyField(const FieldDecl *field, CodeGenFunction::Destroyer *destroyer,
1543 bool useEHCleanupForArray)
1544 : field(field), destroyer(destroyer),
1545 useEHCleanupForArray(useEHCleanupForArray) {}
1547 void Emit(CodeGenFunction &CGF, Flags flags) override {
1548 // Find the address of the field.
1549 llvm::Value *thisValue = CGF.LoadCXXThis();
1550 QualType RecordTy = CGF.getContext().getTagDeclType(field->getParent());
1551 LValue ThisLV = CGF.MakeAddrLValue(thisValue, RecordTy);
1552 LValue LV = CGF.EmitLValueForField(ThisLV, field);
1553 assert(LV.isSimple());
1555 CGF.emitDestroy(LV.getAddress(), field->getType(), destroyer,
1556 flags.isForNormalCleanup() && useEHCleanupForArray);
1561 /// \brief Emit all code that comes at the end of class's
1562 /// destructor. This is to call destructors on members and base classes
1563 /// in reverse order of their construction.
1564 void CodeGenFunction::EnterDtorCleanups(const CXXDestructorDecl *DD,
1565 CXXDtorType DtorType) {
1566 assert((!DD->isTrivial() || DD->hasAttr<DLLExportAttr>()) &&
1567 "Should not emit dtor epilogue for non-exported trivial dtor!");
1569 // The deleting-destructor phase just needs to call the appropriate
1570 // operator delete that Sema picked up.
1571 if (DtorType == Dtor_Deleting) {
1572 assert(DD->getOperatorDelete() &&
1573 "operator delete missing - EnterDtorCleanups");
1574 if (CXXStructorImplicitParamValue) {
1575 // If there is an implicit param to the deleting dtor, it's a boolean
1576 // telling whether we should call delete at the end of the dtor.
1577 EHStack.pushCleanup<CallDtorDeleteConditional>(
1578 NormalAndEHCleanup, CXXStructorImplicitParamValue);
1580 EHStack.pushCleanup<CallDtorDelete>(NormalAndEHCleanup);
1585 const CXXRecordDecl *ClassDecl = DD->getParent();
1587 // Unions have no bases and do not call field destructors.
1588 if (ClassDecl->isUnion())
1591 // The complete-destructor phase just destructs all the virtual bases.
1592 if (DtorType == Dtor_Complete) {
1594 // We push them in the forward order so that they'll be popped in
1595 // the reverse order.
1596 for (const auto &Base : ClassDecl->vbases()) {
1597 CXXRecordDecl *BaseClassDecl
1598 = cast<CXXRecordDecl>(Base.getType()->getAs<RecordType>()->getDecl());
1600 // Ignore trivial destructors.
1601 if (BaseClassDecl->hasTrivialDestructor())
1604 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1606 /*BaseIsVirtual*/ true);
1612 assert(DtorType == Dtor_Base);
1614 // Destroy non-virtual bases.
1615 for (const auto &Base : ClassDecl->bases()) {
1616 // Ignore virtual bases.
1617 if (Base.isVirtual())
1620 CXXRecordDecl *BaseClassDecl = Base.getType()->getAsCXXRecordDecl();
1622 // Ignore trivial destructors.
1623 if (BaseClassDecl->hasTrivialDestructor())
1626 EHStack.pushCleanup<CallBaseDtor>(NormalAndEHCleanup,
1628 /*BaseIsVirtual*/ false);
1631 // Destroy direct fields.
1632 for (const auto *Field : ClassDecl->fields()) {
1633 QualType type = Field->getType();
1634 QualType::DestructionKind dtorKind = type.isDestructedType();
1635 if (!dtorKind) continue;
1637 // Anonymous union members do not have their destructors called.
1638 const RecordType *RT = type->getAsUnionType();
1639 if (RT && RT->getDecl()->isAnonymousStructOrUnion()) continue;
1641 CleanupKind cleanupKind = getCleanupKind(dtorKind);
1642 EHStack.pushCleanup<DestroyField>(cleanupKind, Field,
1643 getDestroyer(dtorKind),
1644 cleanupKind & EHCleanup);
1648 /// EmitCXXAggrConstructorCall - Emit a loop to call a particular
1649 /// constructor for each of several members of an array.
1651 /// \param ctor the constructor to call for each element
1652 /// \param arrayType the type of the array to initialize
1653 /// \param arrayBegin an arrayType*
1654 /// \param zeroInitialize true if each element should be
1655 /// zero-initialized before it is constructed
1656 void CodeGenFunction::EmitCXXAggrConstructorCall(
1657 const CXXConstructorDecl *ctor, const ConstantArrayType *arrayType,
1658 llvm::Value *arrayBegin, const CXXConstructExpr *E, bool zeroInitialize) {
1659 QualType elementType;
1660 llvm::Value *numElements =
1661 emitArrayLength(arrayType, elementType, arrayBegin);
1663 EmitCXXAggrConstructorCall(ctor, numElements, arrayBegin, E, zeroInitialize);
1666 /// EmitCXXAggrConstructorCall - Emit a loop to call a particular
1667 /// constructor for each of several members of an array.
1669 /// \param ctor the constructor to call for each element
1670 /// \param numElements the number of elements in the array;
1672 /// \param arrayBegin a T*, where T is the type constructed by ctor
1673 /// \param zeroInitialize true if each element should be
1674 /// zero-initialized before it is constructed
1675 void CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *ctor,
1676 llvm::Value *numElements,
1677 llvm::Value *arrayBegin,
1678 const CXXConstructExpr *E,
1679 bool zeroInitialize) {
1681 // It's legal for numElements to be zero. This can happen both
1682 // dynamically, because x can be zero in 'new A[x]', and statically,
1683 // because of GCC extensions that permit zero-length arrays. There
1684 // are probably legitimate places where we could assume that this
1685 // doesn't happen, but it's not clear that it's worth it.
1686 llvm::BranchInst *zeroCheckBranch = nullptr;
1688 // Optimize for a constant count.
1689 llvm::ConstantInt *constantCount
1690 = dyn_cast<llvm::ConstantInt>(numElements);
1691 if (constantCount) {
1692 // Just skip out if the constant count is zero.
1693 if (constantCount->isZero()) return;
1695 // Otherwise, emit the check.
1697 llvm::BasicBlock *loopBB = createBasicBlock("new.ctorloop");
1698 llvm::Value *iszero = Builder.CreateIsNull(numElements, "isempty");
1699 zeroCheckBranch = Builder.CreateCondBr(iszero, loopBB, loopBB);
1703 // Find the end of the array.
1704 llvm::Value *arrayEnd = Builder.CreateInBoundsGEP(arrayBegin, numElements,
1707 // Enter the loop, setting up a phi for the current location to initialize.
1708 llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
1709 llvm::BasicBlock *loopBB = createBasicBlock("arrayctor.loop");
1711 llvm::PHINode *cur = Builder.CreatePHI(arrayBegin->getType(), 2,
1713 cur->addIncoming(arrayBegin, entryBB);
1715 // Inside the loop body, emit the constructor call on the array element.
1717 QualType type = getContext().getTypeDeclType(ctor->getParent());
1719 // Zero initialize the storage, if requested.
1721 EmitNullInitialization(cur, type);
1723 // C++ [class.temporary]p4:
1724 // There are two contexts in which temporaries are destroyed at a different
1725 // point than the end of the full-expression. The first context is when a
1726 // default constructor is called to initialize an element of an array.
1727 // If the constructor has one or more default arguments, the destruction of
1728 // every temporary created in a default argument expression is sequenced
1729 // before the construction of the next array element, if any.
1732 RunCleanupsScope Scope(*this);
1734 // Evaluate the constructor and its arguments in a regular
1735 // partial-destroy cleanup.
1736 if (getLangOpts().Exceptions &&
1737 !ctor->getParent()->hasTrivialDestructor()) {
1738 Destroyer *destroyer = destroyCXXObject;
1739 pushRegularPartialArrayCleanup(arrayBegin, cur, type, *destroyer);
1742 EmitCXXConstructorCall(ctor, Ctor_Complete, /*ForVirtualBase=*/false,
1743 /*Delegating=*/false, cur, E);
1746 // Go to the next element.
1748 Builder.CreateInBoundsGEP(cur, llvm::ConstantInt::get(SizeTy, 1),
1750 cur->addIncoming(next, Builder.GetInsertBlock());
1752 // Check whether that's the end of the loop.
1753 llvm::Value *done = Builder.CreateICmpEQ(next, arrayEnd, "arrayctor.done");
1754 llvm::BasicBlock *contBB = createBasicBlock("arrayctor.cont");
1755 Builder.CreateCondBr(done, contBB, loopBB);
1757 // Patch the earlier check to skip over the loop.
1758 if (zeroCheckBranch) zeroCheckBranch->setSuccessor(0, contBB);
1763 void CodeGenFunction::destroyCXXObject(CodeGenFunction &CGF,
1766 const RecordType *rtype = type->castAs<RecordType>();
1767 const CXXRecordDecl *record = cast<CXXRecordDecl>(rtype->getDecl());
1768 const CXXDestructorDecl *dtor = record->getDestructor();
1769 assert(!dtor->isTrivial());
1770 CGF.EmitCXXDestructorCall(dtor, Dtor_Complete, /*for vbase*/ false,
1771 /*Delegating=*/false, addr);
1774 void CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
1776 bool ForVirtualBase,
1777 bool Delegating, llvm::Value *This,
1778 const CXXConstructExpr *E) {
1779 // C++11 [class.mfct.non-static]p2:
1780 // If a non-static member function of a class X is called for an object that
1781 // is not of type X, or of a type derived from X, the behavior is undefined.
1782 // FIXME: Provide a source location here.
1783 EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall, SourceLocation(), This,
1784 getContext().getRecordType(D->getParent()));
1786 if (D->isTrivial() && D->isDefaultConstructor()) {
1787 assert(E->getNumArgs() == 0 && "trivial default ctor with args");
1791 // If this is a trivial constructor, just emit what's needed. If this is a
1792 // union copy constructor, we must emit a memcpy, because the AST does not
1794 if (isMemcpyEquivalentSpecialMember(D)) {
1795 assert(E->getNumArgs() == 1 && "unexpected argcount for trivial ctor");
1797 const Expr *Arg = E->getArg(0);
1798 QualType SrcTy = Arg->getType();
1799 llvm::Value *Src = EmitLValue(Arg).getAddress();
1800 QualType DestTy = getContext().getTypeDeclType(D->getParent());
1801 EmitAggregateCopyCtor(This, Src, DestTy, SrcTy);
1807 // Push the this ptr.
1808 Args.add(RValue::get(This), D->getThisType(getContext()));
1810 // Add the rest of the user-supplied arguments.
1811 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1812 EmitCallArgs(Args, FPT, E->arg_begin(), E->arg_end(), E->getConstructor());
1814 // Insert any ABI-specific implicit constructor arguments.
1815 unsigned ExtraArgs = CGM.getCXXABI().addImplicitConstructorArgs(
1816 *this, D, Type, ForVirtualBase, Delegating, Args);
1819 llvm::Value *Callee = CGM.getAddrOfCXXStructor(D, getFromCtorType(Type));
1820 const CGFunctionInfo &Info =
1821 CGM.getTypes().arrangeCXXConstructorCall(Args, D, Type, ExtraArgs);
1822 EmitCall(Info, Callee, ReturnValueSlot(), Args, D);
1826 CodeGenFunction::EmitSynthesizedCXXCopyCtorCall(const CXXConstructorDecl *D,
1827 llvm::Value *This, llvm::Value *Src,
1828 const CXXConstructExpr *E) {
1829 if (isMemcpyEquivalentSpecialMember(D)) {
1830 assert(E->getNumArgs() == 1 && "unexpected argcount for trivial ctor");
1831 assert(D->isCopyOrMoveConstructor() &&
1832 "trivial 1-arg ctor not a copy/move ctor");
1833 EmitAggregateCopyCtor(This, Src,
1834 getContext().getTypeDeclType(D->getParent()),
1835 E->arg_begin()->getType());
1838 llvm::Value *Callee = CGM.getAddrOfCXXStructor(D, StructorType::Complete);
1839 assert(D->isInstance() &&
1840 "Trying to emit a member call expr on a static method!");
1842 const FunctionProtoType *FPT = D->getType()->castAs<FunctionProtoType>();
1846 // Push the this ptr.
1847 Args.add(RValue::get(This), D->getThisType(getContext()));
1849 // Push the src ptr.
1850 QualType QT = *(FPT->param_type_begin());
1851 llvm::Type *t = CGM.getTypes().ConvertType(QT);
1852 Src = Builder.CreateBitCast(Src, t);
1853 Args.add(RValue::get(Src), QT);
1855 // Skip over first argument (Src).
1856 EmitCallArgs(Args, FPT, E->arg_begin() + 1, E->arg_end(), E->getConstructor(),
1857 /*ParamsToSkip*/ 1);
1859 EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, RequiredArgs::All),
1860 Callee, ReturnValueSlot(), Args, D);
1864 CodeGenFunction::EmitDelegateCXXConstructorCall(const CXXConstructorDecl *Ctor,
1865 CXXCtorType CtorType,
1866 const FunctionArgList &Args,
1867 SourceLocation Loc) {
1868 CallArgList DelegateArgs;
1870 FunctionArgList::const_iterator I = Args.begin(), E = Args.end();
1871 assert(I != E && "no parameters to constructor");
1874 DelegateArgs.add(RValue::get(LoadCXXThis()), (*I)->getType());
1878 if (llvm::Value *VTT = GetVTTParameter(GlobalDecl(Ctor, CtorType),
1879 /*ForVirtualBase=*/false,
1880 /*Delegating=*/true)) {
1881 QualType VoidPP = getContext().getPointerType(getContext().VoidPtrTy);
1882 DelegateArgs.add(RValue::get(VTT), VoidPP);
1884 if (CGM.getCXXABI().NeedsVTTParameter(CurGD)) {
1885 assert(I != E && "cannot skip vtt parameter, already done with args");
1886 assert((*I)->getType() == VoidPP && "skipping parameter not of vtt type");
1891 // Explicit arguments.
1892 for (; I != E; ++I) {
1893 const VarDecl *param = *I;
1894 // FIXME: per-argument source location
1895 EmitDelegateCallArg(DelegateArgs, param, Loc);
1898 llvm::Value *Callee =
1899 CGM.getAddrOfCXXStructor(Ctor, getFromCtorType(CtorType));
1900 EmitCall(CGM.getTypes()
1901 .arrangeCXXStructorDeclaration(Ctor, getFromCtorType(CtorType)),
1902 Callee, ReturnValueSlot(), DelegateArgs, Ctor);
1906 struct CallDelegatingCtorDtor : EHScopeStack::Cleanup {
1907 const CXXDestructorDecl *Dtor;
1911 CallDelegatingCtorDtor(const CXXDestructorDecl *D, llvm::Value *Addr,
1913 : Dtor(D), Addr(Addr), Type(Type) {}
1915 void Emit(CodeGenFunction &CGF, Flags flags) override {
1916 CGF.EmitCXXDestructorCall(Dtor, Type, /*ForVirtualBase=*/false,
1917 /*Delegating=*/true, Addr);
1923 CodeGenFunction::EmitDelegatingCXXConstructorCall(const CXXConstructorDecl *Ctor,
1924 const FunctionArgList &Args) {
1925 assert(Ctor->isDelegatingConstructor());
1927 llvm::Value *ThisPtr = LoadCXXThis();
1929 QualType Ty = getContext().getTagDeclType(Ctor->getParent());
1930 CharUnits Alignment = getContext().getTypeAlignInChars(Ty);
1931 AggValueSlot AggSlot =
1932 AggValueSlot::forAddr(ThisPtr, Alignment, Qualifiers(),
1933 AggValueSlot::IsDestructed,
1934 AggValueSlot::DoesNotNeedGCBarriers,
1935 AggValueSlot::IsNotAliased);
1937 EmitAggExpr(Ctor->init_begin()[0]->getInit(), AggSlot);
1939 const CXXRecordDecl *ClassDecl = Ctor->getParent();
1940 if (CGM.getLangOpts().Exceptions && !ClassDecl->hasTrivialDestructor()) {
1942 CurGD.getCtorType() == Ctor_Complete ? Dtor_Complete : Dtor_Base;
1944 EHStack.pushCleanup<CallDelegatingCtorDtor>(EHCleanup,
1945 ClassDecl->getDestructor(),
1950 void CodeGenFunction::EmitCXXDestructorCall(const CXXDestructorDecl *DD,
1952 bool ForVirtualBase,
1954 llvm::Value *This) {
1955 CGM.getCXXABI().EmitDestructorCall(*this, DD, Type, ForVirtualBase,
1960 struct CallLocalDtor : EHScopeStack::Cleanup {
1961 const CXXDestructorDecl *Dtor;
1964 CallLocalDtor(const CXXDestructorDecl *D, llvm::Value *Addr)
1965 : Dtor(D), Addr(Addr) {}
1967 void Emit(CodeGenFunction &CGF, Flags flags) override {
1968 CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
1969 /*ForVirtualBase=*/false,
1970 /*Delegating=*/false, Addr);
1975 void CodeGenFunction::PushDestructorCleanup(const CXXDestructorDecl *D,
1976 llvm::Value *Addr) {
1977 EHStack.pushCleanup<CallLocalDtor>(NormalAndEHCleanup, D, Addr);
1980 void CodeGenFunction::PushDestructorCleanup(QualType T, llvm::Value *Addr) {
1981 CXXRecordDecl *ClassDecl = T->getAsCXXRecordDecl();
1982 if (!ClassDecl) return;
1983 if (ClassDecl->hasTrivialDestructor()) return;
1985 const CXXDestructorDecl *D = ClassDecl->getDestructor();
1986 assert(D && D->isUsed() && "destructor not marked as used!");
1987 PushDestructorCleanup(D, Addr);
1991 CodeGenFunction::InitializeVTablePointer(BaseSubobject Base,
1992 const CXXRecordDecl *NearestVBase,
1993 CharUnits OffsetFromNearestVBase,
1994 const CXXRecordDecl *VTableClass) {
1995 const CXXRecordDecl *RD = Base.getBase();
1997 // Don't initialize the vtable pointer if the class is marked with the
1998 // 'novtable' attribute.
1999 if ((RD == VTableClass || RD == NearestVBase) &&
2000 VTableClass->hasAttr<MSNoVTableAttr>())
2003 // Compute the address point.
2004 bool NeedsVirtualOffset;
2005 llvm::Value *VTableAddressPoint =
2006 CGM.getCXXABI().getVTableAddressPointInStructor(
2007 *this, VTableClass, Base, NearestVBase, NeedsVirtualOffset);
2008 if (!VTableAddressPoint)
2011 // Compute where to store the address point.
2012 llvm::Value *VirtualOffset = nullptr;
2013 CharUnits NonVirtualOffset = CharUnits::Zero();
2015 if (NeedsVirtualOffset) {
2016 // We need to use the virtual base offset offset because the virtual base
2017 // might have a different offset in the most derived class.
2018 VirtualOffset = CGM.getCXXABI().GetVirtualBaseClassOffset(*this,
2022 NonVirtualOffset = OffsetFromNearestVBase;
2024 // We can just use the base offset in the complete class.
2025 NonVirtualOffset = Base.getBaseOffset();
2028 // Apply the offsets.
2029 llvm::Value *VTableField = LoadCXXThis();
2031 if (!NonVirtualOffset.isZero() || VirtualOffset)
2032 VTableField = ApplyNonVirtualAndVirtualOffset(*this, VTableField,
2036 // Finally, store the address point. Use the same LLVM types as the field to
2037 // support optimization.
2038 llvm::Type *VTablePtrTy =
2039 llvm::FunctionType::get(CGM.Int32Ty, /*isVarArg=*/true)
2042 VTableField = Builder.CreateBitCast(VTableField, VTablePtrTy->getPointerTo());
2043 VTableAddressPoint = Builder.CreateBitCast(VTableAddressPoint, VTablePtrTy);
2044 llvm::StoreInst *Store = Builder.CreateStore(VTableAddressPoint, VTableField);
2045 CGM.DecorateInstruction(Store, CGM.getTBAAInfoForVTablePtr());
2049 CodeGenFunction::InitializeVTablePointers(BaseSubobject Base,
2050 const CXXRecordDecl *NearestVBase,
2051 CharUnits OffsetFromNearestVBase,
2052 bool BaseIsNonVirtualPrimaryBase,
2053 const CXXRecordDecl *VTableClass,
2054 VisitedVirtualBasesSetTy& VBases) {
2055 // If this base is a non-virtual primary base the address point has already
2057 if (!BaseIsNonVirtualPrimaryBase) {
2058 // Initialize the vtable pointer for this base.
2059 InitializeVTablePointer(Base, NearestVBase, OffsetFromNearestVBase,
2063 const CXXRecordDecl *RD = Base.getBase();
2066 for (const auto &I : RD->bases()) {
2067 CXXRecordDecl *BaseDecl
2068 = cast<CXXRecordDecl>(I.getType()->getAs<RecordType>()->getDecl());
2070 // Ignore classes without a vtable.
2071 if (!BaseDecl->isDynamicClass())
2074 CharUnits BaseOffset;
2075 CharUnits BaseOffsetFromNearestVBase;
2076 bool BaseDeclIsNonVirtualPrimaryBase;
2078 if (I.isVirtual()) {
2079 // Check if we've visited this virtual base before.
2080 if (!VBases.insert(BaseDecl).second)
2083 const ASTRecordLayout &Layout =
2084 getContext().getASTRecordLayout(VTableClass);
2086 BaseOffset = Layout.getVBaseClassOffset(BaseDecl);
2087 BaseOffsetFromNearestVBase = CharUnits::Zero();
2088 BaseDeclIsNonVirtualPrimaryBase = false;
2090 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
2092 BaseOffset = Base.getBaseOffset() + Layout.getBaseClassOffset(BaseDecl);
2093 BaseOffsetFromNearestVBase =
2094 OffsetFromNearestVBase + Layout.getBaseClassOffset(BaseDecl);
2095 BaseDeclIsNonVirtualPrimaryBase = Layout.getPrimaryBase() == BaseDecl;
2098 InitializeVTablePointers(BaseSubobject(BaseDecl, BaseOffset),
2099 I.isVirtual() ? BaseDecl : NearestVBase,
2100 BaseOffsetFromNearestVBase,
2101 BaseDeclIsNonVirtualPrimaryBase,
2102 VTableClass, VBases);
2106 void CodeGenFunction::InitializeVTablePointers(const CXXRecordDecl *RD) {
2107 // Ignore classes without a vtable.
2108 if (!RD->isDynamicClass())
2111 // Initialize the vtable pointers for this class and all of its bases.
2112 VisitedVirtualBasesSetTy VBases;
2113 InitializeVTablePointers(BaseSubobject(RD, CharUnits::Zero()),
2114 /*NearestVBase=*/nullptr,
2115 /*OffsetFromNearestVBase=*/CharUnits::Zero(),
2116 /*BaseIsNonVirtualPrimaryBase=*/false, RD, VBases);
2118 if (RD->getNumVBases())
2119 CGM.getCXXABI().initializeHiddenVirtualInheritanceMembers(*this, RD);
2122 llvm::Value *CodeGenFunction::GetVTablePtr(llvm::Value *This,
2124 llvm::Value *VTablePtrSrc = Builder.CreateBitCast(This, Ty->getPointerTo());
2125 llvm::Instruction *VTable = Builder.CreateLoad(VTablePtrSrc, "vtable");
2126 CGM.DecorateInstruction(VTable, CGM.getTBAAInfoForVTablePtr());
2130 // If a class has a single non-virtual base and does not introduce or override
2131 // virtual member functions or fields, it will have the same layout as its base.
2132 // This function returns the least derived such class.
2134 // Casting an instance of a base class to such a derived class is technically
2135 // undefined behavior, but it is a relatively common hack for introducing member
2136 // functions on class instances with specific properties (e.g. llvm::Operator)
2137 // that works under most compilers and should not have security implications, so
2138 // we allow it by default. It can be disabled with -fsanitize=cfi-cast-strict.
2139 static const CXXRecordDecl *
2140 LeastDerivedClassWithSameLayout(const CXXRecordDecl *RD) {
2141 if (!RD->field_empty())
2144 if (RD->getNumVBases() != 0)
2147 if (RD->getNumBases() != 1)
2150 for (const CXXMethodDecl *MD : RD->methods()) {
2151 if (MD->isVirtual()) {
2152 // Virtual member functions are only ok if they are implicit destructors
2153 // because the implicit destructor will have the same semantics as the
2154 // base class's destructor if no fields are added.
2155 if (isa<CXXDestructorDecl>(MD) && MD->isImplicit())
2161 return LeastDerivedClassWithSameLayout(
2162 RD->bases_begin()->getType()->getAsCXXRecordDecl());
2165 void CodeGenFunction::EmitVTablePtrCheckForCall(const CXXMethodDecl *MD,
2166 llvm::Value *VTable,
2167 CFITypeCheckKind TCK,
2168 SourceLocation Loc) {
2169 const CXXRecordDecl *ClassDecl = MD->getParent();
2170 if (!SanOpts.has(SanitizerKind::CFICastStrict))
2171 ClassDecl = LeastDerivedClassWithSameLayout(ClassDecl);
2173 EmitVTablePtrCheck(ClassDecl, VTable, TCK, Loc);
2176 void CodeGenFunction::EmitVTablePtrCheckForCast(QualType T,
2177 llvm::Value *Derived,
2179 CFITypeCheckKind TCK,
2180 SourceLocation Loc) {
2181 if (!getLangOpts().CPlusPlus)
2184 auto *ClassTy = T->getAs<RecordType>();
2188 const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(ClassTy->getDecl());
2190 if (!ClassDecl->isCompleteDefinition() || !ClassDecl->isDynamicClass())
2193 SmallString<64> MangledName;
2194 llvm::raw_svector_ostream Out(MangledName);
2195 CGM.getCXXABI().getMangleContext().mangleCXXRTTI(T.getUnqualifiedType(),
2198 // Blacklist based on the mangled type.
2199 if (CGM.getContext().getSanitizerBlacklist().isBlacklistedType(Out.str()))
2202 if (!SanOpts.has(SanitizerKind::CFICastStrict))
2203 ClassDecl = LeastDerivedClassWithSameLayout(ClassDecl);
2205 llvm::BasicBlock *ContBlock = 0;
2208 llvm::Value *DerivedNotNull =
2209 Builder.CreateIsNotNull(Derived, "cast.nonnull");
2211 llvm::BasicBlock *CheckBlock = createBasicBlock("cast.check");
2212 ContBlock = createBasicBlock("cast.cont");
2214 Builder.CreateCondBr(DerivedNotNull, CheckBlock, ContBlock);
2216 EmitBlock(CheckBlock);
2219 llvm::Value *VTable = GetVTablePtr(Derived, Int8PtrTy);
2220 EmitVTablePtrCheck(ClassDecl, VTable, TCK, Loc);
2223 Builder.CreateBr(ContBlock);
2224 EmitBlock(ContBlock);
2228 void CodeGenFunction::EmitVTablePtrCheck(const CXXRecordDecl *RD,
2229 llvm::Value *VTable,
2230 CFITypeCheckKind TCK,
2231 SourceLocation Loc) {
2232 if (CGM.IsCFIBlacklistedRecord(RD))
2235 SanitizerScope SanScope(this);
2237 std::string OutName;
2238 llvm::raw_string_ostream Out(OutName);
2239 CGM.getCXXABI().getMangleContext().mangleCXXVTableBitSet(RD, Out);
2241 llvm::Value *BitSetName = llvm::MetadataAsValue::get(
2242 getLLVMContext(), llvm::MDString::get(getLLVMContext(), Out.str()));
2244 llvm::Value *CastedVTable = Builder.CreateBitCast(VTable, Int8PtrTy);
2245 llvm::Value *BitSetTest =
2246 Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::bitset_test),
2247 {CastedVTable, BitSetName});
2252 M = SanitizerKind::CFIVCall;
2255 M = SanitizerKind::CFINVCall;
2257 case CFITCK_DerivedCast:
2258 M = SanitizerKind::CFIDerivedCast;
2260 case CFITCK_UnrelatedCast:
2261 M = SanitizerKind::CFIUnrelatedCast;
2265 llvm::Constant *StaticData[] = {
2266 EmitCheckSourceLocation(Loc),
2267 EmitCheckTypeDescriptor(QualType(RD->getTypeForDecl(), 0)),
2268 llvm::ConstantInt::get(Int8Ty, TCK),
2270 EmitCheck(std::make_pair(BitSetTest, M), "cfi_bad_type", StaticData,
2274 // FIXME: Ideally Expr::IgnoreParenNoopCasts should do this, but it doesn't do
2275 // quite what we want.
2276 static const Expr *skipNoOpCastsAndParens(const Expr *E) {
2278 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
2279 E = PE->getSubExpr();
2283 if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
2284 if (CE->getCastKind() == CK_NoOp) {
2285 E = CE->getSubExpr();
2289 if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
2290 if (UO->getOpcode() == UO_Extension) {
2291 E = UO->getSubExpr();
2300 CodeGenFunction::CanDevirtualizeMemberFunctionCall(const Expr *Base,
2301 const CXXMethodDecl *MD) {
2302 // When building with -fapple-kext, all calls must go through the vtable since
2303 // the kernel linker can do runtime patching of vtables.
2304 if (getLangOpts().AppleKext)
2307 // If the most derived class is marked final, we know that no subclass can
2308 // override this member function and so we can devirtualize it. For example:
2310 // struct A { virtual void f(); }
2311 // struct B final : A { };
2317 const CXXRecordDecl *MostDerivedClassDecl = Base->getBestDynamicClassType();
2318 if (MostDerivedClassDecl->hasAttr<FinalAttr>())
2321 // If the member function is marked 'final', we know that it can't be
2322 // overridden and can therefore devirtualize it.
2323 if (MD->hasAttr<FinalAttr>())
2326 // Similarly, if the class itself is marked 'final' it can't be overridden
2327 // and we can therefore devirtualize the member function call.
2328 if (MD->getParent()->hasAttr<FinalAttr>())
2331 Base = skipNoOpCastsAndParens(Base);
2332 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) {
2333 if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
2334 // This is a record decl. We know the type and can devirtualize it.
2335 return VD->getType()->isRecordType();
2341 // We can devirtualize calls on an object accessed by a class member access
2342 // expression, since by C++11 [basic.life]p6 we know that it can't refer to
2343 // a derived class object constructed in the same location.
2344 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Base))
2345 if (const ValueDecl *VD = dyn_cast<ValueDecl>(ME->getMemberDecl()))
2346 return VD->getType()->isRecordType();
2348 // We can always devirtualize calls on temporary object expressions.
2349 if (isa<CXXConstructExpr>(Base))
2352 // And calls on bound temporaries.
2353 if (isa<CXXBindTemporaryExpr>(Base))
2356 // Check if this is a call expr that returns a record type.
2357 if (const CallExpr *CE = dyn_cast<CallExpr>(Base))
2358 return CE->getCallReturnType(getContext())->isRecordType();
2360 // We can't devirtualize the call.
2364 void CodeGenFunction::EmitForwardingCallToLambda(
2365 const CXXMethodDecl *callOperator,
2366 CallArgList &callArgs) {
2367 // Get the address of the call operator.
2368 const CGFunctionInfo &calleeFnInfo =
2369 CGM.getTypes().arrangeCXXMethodDeclaration(callOperator);
2370 llvm::Value *callee =
2371 CGM.GetAddrOfFunction(GlobalDecl(callOperator),
2372 CGM.getTypes().GetFunctionType(calleeFnInfo));
2374 // Prepare the return slot.
2375 const FunctionProtoType *FPT =
2376 callOperator->getType()->castAs<FunctionProtoType>();
2377 QualType resultType = FPT->getReturnType();
2378 ReturnValueSlot returnSlot;
2379 if (!resultType->isVoidType() &&
2380 calleeFnInfo.getReturnInfo().getKind() == ABIArgInfo::Indirect &&
2381 !hasScalarEvaluationKind(calleeFnInfo.getReturnType()))
2382 returnSlot = ReturnValueSlot(ReturnValue, resultType.isVolatileQualified());
2384 // We don't need to separately arrange the call arguments because
2385 // the call can't be variadic anyway --- it's impossible to forward
2386 // variadic arguments.
2388 // Now emit our call.
2389 RValue RV = EmitCall(calleeFnInfo, callee, returnSlot,
2390 callArgs, callOperator);
2392 // If necessary, copy the returned value into the slot.
2393 if (!resultType->isVoidType() && returnSlot.isNull())
2394 EmitReturnOfRValue(RV, resultType);
2396 EmitBranchThroughCleanup(ReturnBlock);
2399 void CodeGenFunction::EmitLambdaBlockInvokeBody() {
2400 const BlockDecl *BD = BlockInfo->getBlockDecl();
2401 const VarDecl *variable = BD->capture_begin()->getVariable();
2402 const CXXRecordDecl *Lambda = variable->getType()->getAsCXXRecordDecl();
2404 // Start building arguments for forwarding call
2405 CallArgList CallArgs;
2407 QualType ThisType = getContext().getPointerType(getContext().getRecordType(Lambda));
2408 llvm::Value *ThisPtr = GetAddrOfBlockDecl(variable, false);
2409 CallArgs.add(RValue::get(ThisPtr), ThisType);
2411 // Add the rest of the parameters.
2412 for (auto param : BD->params())
2413 EmitDelegateCallArg(CallArgs, param, param->getLocStart());
2415 assert(!Lambda->isGenericLambda() &&
2416 "generic lambda interconversion to block not implemented");
2417 EmitForwardingCallToLambda(Lambda->getLambdaCallOperator(), CallArgs);
2420 void CodeGenFunction::EmitLambdaToBlockPointerBody(FunctionArgList &Args) {
2421 if (cast<CXXMethodDecl>(CurCodeDecl)->isVariadic()) {
2422 // FIXME: Making this work correctly is nasty because it requires either
2423 // cloning the body of the call operator or making the call operator forward.
2424 CGM.ErrorUnsupported(CurCodeDecl, "lambda conversion to variadic function");
2428 EmitFunctionBody(Args, cast<FunctionDecl>(CurGD.getDecl())->getBody());
2431 void CodeGenFunction::EmitLambdaDelegatingInvokeBody(const CXXMethodDecl *MD) {
2432 const CXXRecordDecl *Lambda = MD->getParent();
2434 // Start building arguments for forwarding call
2435 CallArgList CallArgs;
2437 QualType ThisType = getContext().getPointerType(getContext().getRecordType(Lambda));
2438 llvm::Value *ThisPtr = llvm::UndefValue::get(getTypes().ConvertType(ThisType));
2439 CallArgs.add(RValue::get(ThisPtr), ThisType);
2441 // Add the rest of the parameters.
2442 for (auto Param : MD->params())
2443 EmitDelegateCallArg(CallArgs, Param, Param->getLocStart());
2445 const CXXMethodDecl *CallOp = Lambda->getLambdaCallOperator();
2446 // For a generic lambda, find the corresponding call operator specialization
2447 // to which the call to the static-invoker shall be forwarded.
2448 if (Lambda->isGenericLambda()) {
2449 assert(MD->isFunctionTemplateSpecialization());
2450 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
2451 FunctionTemplateDecl *CallOpTemplate = CallOp->getDescribedFunctionTemplate();
2452 void *InsertPos = nullptr;
2453 FunctionDecl *CorrespondingCallOpSpecialization =
2454 CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos);
2455 assert(CorrespondingCallOpSpecialization);
2456 CallOp = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
2458 EmitForwardingCallToLambda(CallOp, CallArgs);
2461 void CodeGenFunction::EmitLambdaStaticInvokeFunction(const CXXMethodDecl *MD) {
2462 if (MD->isVariadic()) {
2463 // FIXME: Making this work correctly is nasty because it requires either
2464 // cloning the body of the call operator or making the call operator forward.
2465 CGM.ErrorUnsupported(MD, "lambda conversion to variadic function");
2469 EmitLambdaDelegatingInvokeBody(MD);