1 //===--- CGExprCXX.cpp - Emit LLVM Code for C++ expressions ---------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This contains code dealing with code generation of C++ expressions
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "CGCUDARuntime.h"
14 #include "CGCXXABI.h"
15 #include "CGDebugInfo.h"
16 #include "CGObjCRuntime.h"
17 #include "CodeGenFunction.h"
18 #include "ConstantEmitter.h"
19 #include "TargetInfo.h"
20 #include "clang/Basic/CodeGenOptions.h"
21 #include "clang/CodeGen/CGFunctionInfo.h"
22 #include "llvm/IR/Intrinsics.h"
23 
24 using namespace clang;
25 using namespace CodeGen;
26 
27 namespace {
28 struct MemberCallInfo {
29   RequiredArgs ReqArgs;
30   // Number of prefix arguments for the call. Ignores the `this` pointer.
31   unsigned PrefixSize;
32 };
33 }
34 
35 static MemberCallInfo
36 commonEmitCXXMemberOrOperatorCall(CodeGenFunction &CGF, const CXXMethodDecl *MD,
37                                   llvm::Value *This, llvm::Value *ImplicitParam,
38                                   QualType ImplicitParamTy, const CallExpr *CE,
39                                   CallArgList &Args, CallArgList *RtlArgs) {
40   assert(CE == nullptr || isa<CXXMemberCallExpr>(CE) ||
41          isa<CXXOperatorCallExpr>(CE));
42   assert(MD->isInstance() &&
43          "Trying to emit a member or operator call expr on a static method!");
44 
45   // Push the this ptr.
46   const CXXRecordDecl *RD =
47       CGF.CGM.getCXXABI().getThisArgumentTypeForMethod(MD);
48   Args.add(RValue::get(This), CGF.getTypes().DeriveThisType(RD, MD));
49 
50   // If there is an implicit parameter (e.g. VTT), emit it.
51   if (ImplicitParam) {
52     Args.add(RValue::get(ImplicitParam), ImplicitParamTy);
53   }
54 
55   const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
56   RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size());
57   unsigned PrefixSize = Args.size() - 1;
58 
59   // And the rest of the call args.
60   if (RtlArgs) {
61     // Special case: if the caller emitted the arguments right-to-left already
62     // (prior to emitting the *this argument), we're done. This happens for
63     // assignment operators.
64     Args.addFrom(*RtlArgs);
65   } else if (CE) {
66     // Special case: skip first argument of CXXOperatorCall (it is "this").
67     unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0;
68     CGF.EmitCallArgs(Args, FPT, drop_begin(CE->arguments(), ArgsToSkip),
69                      CE->getDirectCallee());
70   } else {
71     assert(
72         FPT->getNumParams() == 0 &&
73         "No CallExpr specified for function with non-zero number of arguments");
74   }
75   return {required, PrefixSize};
76 }
77 
78 RValue CodeGenFunction::EmitCXXMemberOrOperatorCall(
79     const CXXMethodDecl *MD, const CGCallee &Callee,
80     ReturnValueSlot ReturnValue,
81     llvm::Value *This, llvm::Value *ImplicitParam, QualType ImplicitParamTy,
82     const CallExpr *CE, CallArgList *RtlArgs) {
83   const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
84   CallArgList Args;
85   MemberCallInfo CallInfo = commonEmitCXXMemberOrOperatorCall(
86       *this, MD, This, ImplicitParam, ImplicitParamTy, CE, Args, RtlArgs);
87   auto &FnInfo = CGM.getTypes().arrangeCXXMethodCall(
88       Args, FPT, CallInfo.ReqArgs, CallInfo.PrefixSize);
89   return EmitCall(FnInfo, Callee, ReturnValue, Args, nullptr,
90                   CE && CE == MustTailCall,
91                   CE ? CE->getExprLoc() : SourceLocation());
92 }
93 
94 RValue CodeGenFunction::EmitCXXDestructorCall(
95     GlobalDecl Dtor, const CGCallee &Callee, llvm::Value *This, QualType ThisTy,
96     llvm::Value *ImplicitParam, QualType ImplicitParamTy, const CallExpr *CE) {
97   const CXXMethodDecl *DtorDecl = cast<CXXMethodDecl>(Dtor.getDecl());
98 
99   assert(!ThisTy.isNull());
100   assert(ThisTy->getAsCXXRecordDecl() == DtorDecl->getParent() &&
101          "Pointer/Object mixup");
102 
103   LangAS SrcAS = ThisTy.getAddressSpace();
104   LangAS DstAS = DtorDecl->getMethodQualifiers().getAddressSpace();
105   if (SrcAS != DstAS) {
106     QualType DstTy = DtorDecl->getThisType();
107     llvm::Type *NewType = CGM.getTypes().ConvertType(DstTy);
108     This = getTargetHooks().performAddrSpaceCast(*this, This, SrcAS, DstAS,
109                                                  NewType);
110   }
111 
112   CallArgList Args;
113   commonEmitCXXMemberOrOperatorCall(*this, DtorDecl, This, ImplicitParam,
114                                     ImplicitParamTy, CE, Args, nullptr);
115   return EmitCall(CGM.getTypes().arrangeCXXStructorDeclaration(Dtor), Callee,
116                   ReturnValueSlot(), Args, nullptr, CE && CE == MustTailCall,
117                   CE ? CE->getExprLoc() : SourceLocation{});
118 }
119 
120 RValue CodeGenFunction::EmitCXXPseudoDestructorExpr(
121                                             const CXXPseudoDestructorExpr *E) {
122   QualType DestroyedType = E->getDestroyedType();
123   if (DestroyedType.hasStrongOrWeakObjCLifetime()) {
124     // Automatic Reference Counting:
125     //   If the pseudo-expression names a retainable object with weak or
126     //   strong lifetime, the object shall be released.
127     Expr *BaseExpr = E->getBase();
128     Address BaseValue = Address::invalid();
129     Qualifiers BaseQuals;
130 
131     // If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar.
132     if (E->isArrow()) {
133       BaseValue = EmitPointerWithAlignment(BaseExpr);
134       const auto *PTy = BaseExpr->getType()->castAs<PointerType>();
135       BaseQuals = PTy->getPointeeType().getQualifiers();
136     } else {
137       LValue BaseLV = EmitLValue(BaseExpr);
138       BaseValue = BaseLV.getAddress(*this);
139       QualType BaseTy = BaseExpr->getType();
140       BaseQuals = BaseTy.getQualifiers();
141     }
142 
143     switch (DestroyedType.getObjCLifetime()) {
144     case Qualifiers::OCL_None:
145     case Qualifiers::OCL_ExplicitNone:
146     case Qualifiers::OCL_Autoreleasing:
147       break;
148 
149     case Qualifiers::OCL_Strong:
150       EmitARCRelease(Builder.CreateLoad(BaseValue,
151                         DestroyedType.isVolatileQualified()),
152                      ARCPreciseLifetime);
153       break;
154 
155     case Qualifiers::OCL_Weak:
156       EmitARCDestroyWeak(BaseValue);
157       break;
158     }
159   } else {
160     // C++ [expr.pseudo]p1:
161     //   The result shall only be used as the operand for the function call
162     //   operator (), and the result of such a call has type void. The only
163     //   effect is the evaluation of the postfix-expression before the dot or
164     //   arrow.
165     EmitIgnoredExpr(E->getBase());
166   }
167 
168   return RValue::get(nullptr);
169 }
170 
171 static CXXRecordDecl *getCXXRecord(const Expr *E) {
172   QualType T = E->getType();
173   if (const PointerType *PTy = T->getAs<PointerType>())
174     T = PTy->getPointeeType();
175   const RecordType *Ty = T->castAs<RecordType>();
176   return cast<CXXRecordDecl>(Ty->getDecl());
177 }
178 
179 // Note: This function also emit constructor calls to support a MSVC
180 // extensions allowing explicit constructor function call.
181 RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE,
182                                               ReturnValueSlot ReturnValue) {
183   const Expr *callee = CE->getCallee()->IgnoreParens();
184 
185   if (isa<BinaryOperator>(callee))
186     return EmitCXXMemberPointerCallExpr(CE, ReturnValue);
187 
188   const MemberExpr *ME = cast<MemberExpr>(callee);
189   const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl());
190 
191   if (MD->isStatic()) {
192     // The method is static, emit it as we would a regular call.
193     CGCallee callee =
194         CGCallee::forDirect(CGM.GetAddrOfFunction(MD), GlobalDecl(MD));
195     return EmitCall(getContext().getPointerType(MD->getType()), callee, CE,
196                     ReturnValue);
197   }
198 
199   bool HasQualifier = ME->hasQualifier();
200   NestedNameSpecifier *Qualifier = HasQualifier ? ME->getQualifier() : nullptr;
201   bool IsArrow = ME->isArrow();
202   const Expr *Base = ME->getBase();
203 
204   return EmitCXXMemberOrOperatorMemberCallExpr(
205       CE, MD, ReturnValue, HasQualifier, Qualifier, IsArrow, Base);
206 }
207 
208 RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
209     const CallExpr *CE, const CXXMethodDecl *MD, ReturnValueSlot ReturnValue,
210     bool HasQualifier, NestedNameSpecifier *Qualifier, bool IsArrow,
211     const Expr *Base) {
212   assert(isa<CXXMemberCallExpr>(CE) || isa<CXXOperatorCallExpr>(CE));
213 
214   // Compute the object pointer.
215   bool CanUseVirtualCall = MD->isVirtual() && !HasQualifier;
216 
217   const CXXMethodDecl *DevirtualizedMethod = nullptr;
218   if (CanUseVirtualCall &&
219       MD->getDevirtualizedMethod(Base, getLangOpts().AppleKext)) {
220     const CXXRecordDecl *BestDynamicDecl = Base->getBestDynamicClassType();
221     DevirtualizedMethod = MD->getCorrespondingMethodInClass(BestDynamicDecl);
222     assert(DevirtualizedMethod);
223     const CXXRecordDecl *DevirtualizedClass = DevirtualizedMethod->getParent();
224     const Expr *Inner = Base->IgnoreParenBaseCasts();
225     if (DevirtualizedMethod->getReturnType().getCanonicalType() !=
226         MD->getReturnType().getCanonicalType())
227       // If the return types are not the same, this might be a case where more
228       // code needs to run to compensate for it. For example, the derived
229       // method might return a type that inherits form from the return
230       // type of MD and has a prefix.
231       // For now we just avoid devirtualizing these covariant cases.
232       DevirtualizedMethod = nullptr;
233     else if (getCXXRecord(Inner) == DevirtualizedClass)
234       // If the class of the Inner expression is where the dynamic method
235       // is defined, build the this pointer from it.
236       Base = Inner;
237     else if (getCXXRecord(Base) != DevirtualizedClass) {
238       // If the method is defined in a class that is not the best dynamic
239       // one or the one of the full expression, we would have to build
240       // a derived-to-base cast to compute the correct this pointer, but
241       // we don't have support for that yet, so do a virtual call.
242       DevirtualizedMethod = nullptr;
243     }
244   }
245 
246   bool TrivialForCodegen =
247       MD->isTrivial() || (MD->isDefaulted() && MD->getParent()->isUnion());
248   bool TrivialAssignment =
249       TrivialForCodegen &&
250       (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) &&
251       !MD->getParent()->mayInsertExtraPadding();
252 
253   // C++17 demands that we evaluate the RHS of a (possibly-compound) assignment
254   // operator before the LHS.
255   CallArgList RtlArgStorage;
256   CallArgList *RtlArgs = nullptr;
257   LValue TrivialAssignmentRHS;
258   if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(CE)) {
259     if (OCE->isAssignmentOp()) {
260       if (TrivialAssignment) {
261         TrivialAssignmentRHS = EmitLValue(CE->getArg(1));
262       } else {
263         RtlArgs = &RtlArgStorage;
264         EmitCallArgs(*RtlArgs, MD->getType()->castAs<FunctionProtoType>(),
265                      drop_begin(CE->arguments(), 1), CE->getDirectCallee(),
266                      /*ParamsToSkip*/0, EvaluationOrder::ForceRightToLeft);
267       }
268     }
269   }
270 
271   LValue This;
272   if (IsArrow) {
273     LValueBaseInfo BaseInfo;
274     TBAAAccessInfo TBAAInfo;
275     Address ThisValue = EmitPointerWithAlignment(Base, &BaseInfo, &TBAAInfo);
276     This = MakeAddrLValue(ThisValue, Base->getType(), BaseInfo, TBAAInfo);
277   } else {
278     This = EmitLValue(Base);
279   }
280 
281   if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
282     // This is the MSVC p->Ctor::Ctor(...) extension. We assume that's
283     // constructing a new complete object of type Ctor.
284     assert(!RtlArgs);
285     assert(ReturnValue.isNull() && "Constructor shouldn't have return value");
286     CallArgList Args;
287     commonEmitCXXMemberOrOperatorCall(
288         *this, Ctor, This.getPointer(*this), /*ImplicitParam=*/nullptr,
289         /*ImplicitParamTy=*/QualType(), CE, Args, nullptr);
290 
291     EmitCXXConstructorCall(Ctor, Ctor_Complete, /*ForVirtualBase=*/false,
292                            /*Delegating=*/false, This.getAddress(*this), Args,
293                            AggValueSlot::DoesNotOverlap, CE->getExprLoc(),
294                            /*NewPointerIsChecked=*/false);
295     return RValue::get(nullptr);
296   }
297 
298   if (TrivialForCodegen) {
299     if (isa<CXXDestructorDecl>(MD))
300       return RValue::get(nullptr);
301 
302     if (TrivialAssignment) {
303       // We don't like to generate the trivial copy/move assignment operator
304       // when it isn't necessary; just produce the proper effect here.
305       // It's important that we use the result of EmitLValue here rather than
306       // emitting call arguments, in order to preserve TBAA information from
307       // the RHS.
308       LValue RHS = isa<CXXOperatorCallExpr>(CE)
309                        ? TrivialAssignmentRHS
310                        : EmitLValue(*CE->arg_begin());
311       EmitAggregateAssign(This, RHS, CE->getType());
312       return RValue::get(This.getPointer(*this));
313     }
314 
315     assert(MD->getParent()->mayInsertExtraPadding() &&
316            "unknown trivial member function");
317   }
318 
319   // Compute the function type we're calling.
320   const CXXMethodDecl *CalleeDecl =
321       DevirtualizedMethod ? DevirtualizedMethod : MD;
322   const CGFunctionInfo *FInfo = nullptr;
323   if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl))
324     FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
325         GlobalDecl(Dtor, Dtor_Complete));
326   else
327     FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(CalleeDecl);
328 
329   llvm::FunctionType *Ty = CGM.getTypes().GetFunctionType(*FInfo);
330 
331   // C++11 [class.mfct.non-static]p2:
332   //   If a non-static member function of a class X is called for an object that
333   //   is not of type X, or of a type derived from X, the behavior is undefined.
334   SourceLocation CallLoc;
335   ASTContext &C = getContext();
336   if (CE)
337     CallLoc = CE->getExprLoc();
338 
339   SanitizerSet SkippedChecks;
340   if (const auto *CMCE = dyn_cast<CXXMemberCallExpr>(CE)) {
341     auto *IOA = CMCE->getImplicitObjectArgument();
342     bool IsImplicitObjectCXXThis = IsWrappedCXXThis(IOA);
343     if (IsImplicitObjectCXXThis)
344       SkippedChecks.set(SanitizerKind::Alignment, true);
345     if (IsImplicitObjectCXXThis || isa<DeclRefExpr>(IOA))
346       SkippedChecks.set(SanitizerKind::Null, true);
347   }
348   EmitTypeCheck(CodeGenFunction::TCK_MemberCall, CallLoc,
349                 This.getPointer(*this),
350                 C.getRecordType(CalleeDecl->getParent()),
351                 /*Alignment=*/CharUnits::Zero(), SkippedChecks);
352 
353   // C++ [class.virtual]p12:
354   //   Explicit qualification with the scope operator (5.1) suppresses the
355   //   virtual call mechanism.
356   //
357   // We also don't emit a virtual call if the base expression has a record type
358   // because then we know what the type is.
359   bool UseVirtualCall = CanUseVirtualCall && !DevirtualizedMethod;
360 
361   if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl)) {
362     assert(CE->arg_begin() == CE->arg_end() &&
363            "Destructor shouldn't have explicit parameters");
364     assert(ReturnValue.isNull() && "Destructor shouldn't have return value");
365     if (UseVirtualCall) {
366       CGM.getCXXABI().EmitVirtualDestructorCall(*this, Dtor, Dtor_Complete,
367                                                 This.getAddress(*this),
368                                                 cast<CXXMemberCallExpr>(CE));
369     } else {
370       GlobalDecl GD(Dtor, Dtor_Complete);
371       CGCallee Callee;
372       if (getLangOpts().AppleKext && Dtor->isVirtual() && HasQualifier)
373         Callee = BuildAppleKextVirtualCall(Dtor, Qualifier, Ty);
374       else if (!DevirtualizedMethod)
375         Callee =
376             CGCallee::forDirect(CGM.getAddrOfCXXStructor(GD, FInfo, Ty), GD);
377       else {
378         Callee = CGCallee::forDirect(CGM.GetAddrOfFunction(GD, Ty), GD);
379       }
380 
381       QualType ThisTy =
382           IsArrow ? Base->getType()->getPointeeType() : Base->getType();
383       EmitCXXDestructorCall(GD, Callee, This.getPointer(*this), ThisTy,
384                             /*ImplicitParam=*/nullptr,
385                             /*ImplicitParamTy=*/QualType(), CE);
386     }
387     return RValue::get(nullptr);
388   }
389 
390   // FIXME: Uses of 'MD' past this point need to be audited. We may need to use
391   // 'CalleeDecl' instead.
392 
393   CGCallee Callee;
394   if (UseVirtualCall) {
395     Callee = CGCallee::forVirtual(CE, MD, This.getAddress(*this), Ty);
396   } else {
397     if (SanOpts.has(SanitizerKind::CFINVCall) &&
398         MD->getParent()->isDynamicClass()) {
399       llvm::Value *VTable;
400       const CXXRecordDecl *RD;
401       std::tie(VTable, RD) = CGM.getCXXABI().LoadVTablePtr(
402           *this, This.getAddress(*this), CalleeDecl->getParent());
403       EmitVTablePtrCheckForCall(RD, VTable, CFITCK_NVCall, CE->getBeginLoc());
404     }
405 
406     if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier)
407       Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty);
408     else if (!DevirtualizedMethod)
409       Callee =
410           CGCallee::forDirect(CGM.GetAddrOfFunction(MD, Ty), GlobalDecl(MD));
411     else {
412       Callee =
413           CGCallee::forDirect(CGM.GetAddrOfFunction(DevirtualizedMethod, Ty),
414                               GlobalDecl(DevirtualizedMethod));
415     }
416   }
417 
418   if (MD->isVirtual()) {
419     Address NewThisAddr =
420         CGM.getCXXABI().adjustThisArgumentForVirtualFunctionCall(
421             *this, CalleeDecl, This.getAddress(*this), UseVirtualCall);
422     This.setAddress(NewThisAddr);
423   }
424 
425   return EmitCXXMemberOrOperatorCall(
426       CalleeDecl, Callee, ReturnValue, This.getPointer(*this),
427       /*ImplicitParam=*/nullptr, QualType(), CE, RtlArgs);
428 }
429 
430 RValue
431 CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E,
432                                               ReturnValueSlot ReturnValue) {
433   const BinaryOperator *BO =
434       cast<BinaryOperator>(E->getCallee()->IgnoreParens());
435   const Expr *BaseExpr = BO->getLHS();
436   const Expr *MemFnExpr = BO->getRHS();
437 
438   const auto *MPT = MemFnExpr->getType()->castAs<MemberPointerType>();
439   const auto *FPT = MPT->getPointeeType()->castAs<FunctionProtoType>();
440   const auto *RD =
441       cast<CXXRecordDecl>(MPT->getClass()->castAs<RecordType>()->getDecl());
442 
443   // Emit the 'this' pointer.
444   Address This = Address::invalid();
445   if (BO->getOpcode() == BO_PtrMemI)
446     This = EmitPointerWithAlignment(BaseExpr);
447   else
448     This = EmitLValue(BaseExpr).getAddress(*this);
449 
450   EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This.getPointer(),
451                 QualType(MPT->getClass(), 0));
452 
453   // Get the member function pointer.
454   llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr);
455 
456   // Ask the ABI to load the callee.  Note that This is modified.
457   llvm::Value *ThisPtrForCall = nullptr;
458   CGCallee Callee =
459     CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This,
460                                              ThisPtrForCall, MemFnPtr, MPT);
461 
462   CallArgList Args;
463 
464   QualType ThisType =
465     getContext().getPointerType(getContext().getTagDeclType(RD));
466 
467   // Push the this ptr.
468   Args.add(RValue::get(ThisPtrForCall), ThisType);
469 
470   RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, 1);
471 
472   // And the rest of the call args
473   EmitCallArgs(Args, FPT, E->arguments());
474   return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required,
475                                                       /*PrefixSize=*/0),
476                   Callee, ReturnValue, Args, nullptr, E == MustTailCall,
477                   E->getExprLoc());
478 }
479 
480 RValue
481 CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
482                                                const CXXMethodDecl *MD,
483                                                ReturnValueSlot ReturnValue) {
484   assert(MD->isInstance() &&
485          "Trying to emit a member call expr on a static method!");
486   return EmitCXXMemberOrOperatorMemberCallExpr(
487       E, MD, ReturnValue, /*HasQualifier=*/false, /*Qualifier=*/nullptr,
488       /*IsArrow=*/false, E->getArg(0));
489 }
490 
491 RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E,
492                                                ReturnValueSlot ReturnValue) {
493   return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue);
494 }
495 
496 static void EmitNullBaseClassInitialization(CodeGenFunction &CGF,
497                                             Address DestPtr,
498                                             const CXXRecordDecl *Base) {
499   if (Base->isEmpty())
500     return;
501 
502   DestPtr = CGF.Builder.CreateElementBitCast(DestPtr, CGF.Int8Ty);
503 
504   const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base);
505   CharUnits NVSize = Layout.getNonVirtualSize();
506 
507   // We cannot simply zero-initialize the entire base sub-object if vbptrs are
508   // present, they are initialized by the most derived class before calling the
509   // constructor.
510   SmallVector<std::pair<CharUnits, CharUnits>, 1> Stores;
511   Stores.emplace_back(CharUnits::Zero(), NVSize);
512 
513   // Each store is split by the existence of a vbptr.
514   CharUnits VBPtrWidth = CGF.getPointerSize();
515   std::vector<CharUnits> VBPtrOffsets =
516       CGF.CGM.getCXXABI().getVBPtrOffsets(Base);
517   for (CharUnits VBPtrOffset : VBPtrOffsets) {
518     // Stop before we hit any virtual base pointers located in virtual bases.
519     if (VBPtrOffset >= NVSize)
520       break;
521     std::pair<CharUnits, CharUnits> LastStore = Stores.pop_back_val();
522     CharUnits LastStoreOffset = LastStore.first;
523     CharUnits LastStoreSize = LastStore.second;
524 
525     CharUnits SplitBeforeOffset = LastStoreOffset;
526     CharUnits SplitBeforeSize = VBPtrOffset - SplitBeforeOffset;
527     assert(!SplitBeforeSize.isNegative() && "negative store size!");
528     if (!SplitBeforeSize.isZero())
529       Stores.emplace_back(SplitBeforeOffset, SplitBeforeSize);
530 
531     CharUnits SplitAfterOffset = VBPtrOffset + VBPtrWidth;
532     CharUnits SplitAfterSize = LastStoreSize - SplitAfterOffset;
533     assert(!SplitAfterSize.isNegative() && "negative store size!");
534     if (!SplitAfterSize.isZero())
535       Stores.emplace_back(SplitAfterOffset, SplitAfterSize);
536   }
537 
538   // If the type contains a pointer to data member we can't memset it to zero.
539   // Instead, create a null constant and copy it to the destination.
540   // TODO: there are other patterns besides zero that we can usefully memset,
541   // like -1, which happens to be the pattern used by member-pointers.
542   // TODO: isZeroInitializable can be over-conservative in the case where a
543   // virtual base contains a member pointer.
544   llvm::Constant *NullConstantForBase = CGF.CGM.EmitNullConstantForBase(Base);
545   if (!NullConstantForBase->isNullValue()) {
546     llvm::GlobalVariable *NullVariable = new llvm::GlobalVariable(
547         CGF.CGM.getModule(), NullConstantForBase->getType(),
548         /*isConstant=*/true, llvm::GlobalVariable::PrivateLinkage,
549         NullConstantForBase, Twine());
550 
551     CharUnits Align = std::max(Layout.getNonVirtualAlignment(),
552                                DestPtr.getAlignment());
553     NullVariable->setAlignment(Align.getAsAlign());
554 
555     Address SrcPtr = Address(CGF.EmitCastToVoidPtr(NullVariable), Align);
556 
557     // Get and call the appropriate llvm.memcpy overload.
558     for (std::pair<CharUnits, CharUnits> Store : Stores) {
559       CharUnits StoreOffset = Store.first;
560       CharUnits StoreSize = Store.second;
561       llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize);
562       CGF.Builder.CreateMemCpy(
563           CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset),
564           CGF.Builder.CreateConstInBoundsByteGEP(SrcPtr, StoreOffset),
565           StoreSizeVal);
566     }
567 
568   // Otherwise, just memset the whole thing to zero.  This is legal
569   // because in LLVM, all default initializers (other than the ones we just
570   // handled above) are guaranteed to have a bit pattern of all zeros.
571   } else {
572     for (std::pair<CharUnits, CharUnits> Store : Stores) {
573       CharUnits StoreOffset = Store.first;
574       CharUnits StoreSize = Store.second;
575       llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize);
576       CGF.Builder.CreateMemSet(
577           CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset),
578           CGF.Builder.getInt8(0), StoreSizeVal);
579     }
580   }
581 }
582 
583 void
584 CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E,
585                                       AggValueSlot Dest) {
586   assert(!Dest.isIgnored() && "Must have a destination!");
587   const CXXConstructorDecl *CD = E->getConstructor();
588 
589   // If we require zero initialization before (or instead of) calling the
590   // constructor, as can be the case with a non-user-provided default
591   // constructor, emit the zero initialization now, unless destination is
592   // already zeroed.
593   if (E->requiresZeroInitialization() && !Dest.isZeroed()) {
594     switch (E->getConstructionKind()) {
595     case CXXConstructExpr::CK_Delegating:
596     case CXXConstructExpr::CK_Complete:
597       EmitNullInitialization(Dest.getAddress(), E->getType());
598       break;
599     case CXXConstructExpr::CK_VirtualBase:
600     case CXXConstructExpr::CK_NonVirtualBase:
601       EmitNullBaseClassInitialization(*this, Dest.getAddress(),
602                                       CD->getParent());
603       break;
604     }
605   }
606 
607   // If this is a call to a trivial default constructor, do nothing.
608   if (CD->isTrivial() && CD->isDefaultConstructor())
609     return;
610 
611   // Elide the constructor if we're constructing from a temporary.
612   if (getLangOpts().ElideConstructors && E->isElidable()) {
613     // FIXME: This only handles the simplest case, where the source object
614     //        is passed directly as the first argument to the constructor.
615     //        This should also handle stepping though implicit casts and
616     //        conversion sequences which involve two steps, with a
617     //        conversion operator followed by a converting constructor.
618     const Expr *SrcObj = E->getArg(0);
619     assert(SrcObj->isTemporaryObject(getContext(), CD->getParent()));
620     assert(
621         getContext().hasSameUnqualifiedType(E->getType(), SrcObj->getType()));
622     EmitAggExpr(SrcObj, Dest);
623     return;
624   }
625 
626   if (const ArrayType *arrayType
627         = getContext().getAsArrayType(E->getType())) {
628     EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddress(), E,
629                                Dest.isSanitizerChecked());
630   } else {
631     CXXCtorType Type = Ctor_Complete;
632     bool ForVirtualBase = false;
633     bool Delegating = false;
634 
635     switch (E->getConstructionKind()) {
636      case CXXConstructExpr::CK_Delegating:
637       // We should be emitting a constructor; GlobalDecl will assert this
638       Type = CurGD.getCtorType();
639       Delegating = true;
640       break;
641 
642      case CXXConstructExpr::CK_Complete:
643       Type = Ctor_Complete;
644       break;
645 
646      case CXXConstructExpr::CK_VirtualBase:
647       ForVirtualBase = true;
648       LLVM_FALLTHROUGH;
649 
650      case CXXConstructExpr::CK_NonVirtualBase:
651       Type = Ctor_Base;
652      }
653 
654      // Call the constructor.
655      EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating, Dest, E);
656   }
657 }
658 
659 void CodeGenFunction::EmitSynthesizedCXXCopyCtor(Address Dest, Address Src,
660                                                  const Expr *Exp) {
661   if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp))
662     Exp = E->getSubExpr();
663   assert(isa<CXXConstructExpr>(Exp) &&
664          "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr");
665   const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp);
666   const CXXConstructorDecl *CD = E->getConstructor();
667   RunCleanupsScope Scope(*this);
668 
669   // If we require zero initialization before (or instead of) calling the
670   // constructor, as can be the case with a non-user-provided default
671   // constructor, emit the zero initialization now.
672   // FIXME. Do I still need this for a copy ctor synthesis?
673   if (E->requiresZeroInitialization())
674     EmitNullInitialization(Dest, E->getType());
675 
676   assert(!getContext().getAsConstantArrayType(E->getType())
677          && "EmitSynthesizedCXXCopyCtor - Copied-in Array");
678   EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, E);
679 }
680 
681 static CharUnits CalculateCookiePadding(CodeGenFunction &CGF,
682                                         const CXXNewExpr *E) {
683   if (!E->isArray())
684     return CharUnits::Zero();
685 
686   // No cookie is required if the operator new[] being used is the
687   // reserved placement operator new[].
688   if (E->getOperatorNew()->isReservedGlobalPlacementOperator())
689     return CharUnits::Zero();
690 
691   return CGF.CGM.getCXXABI().GetArrayCookieSize(E);
692 }
693 
694 static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF,
695                                         const CXXNewExpr *e,
696                                         unsigned minElements,
697                                         llvm::Value *&numElements,
698                                         llvm::Value *&sizeWithoutCookie) {
699   QualType type = e->getAllocatedType();
700 
701   if (!e->isArray()) {
702     CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
703     sizeWithoutCookie
704       = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity());
705     return sizeWithoutCookie;
706   }
707 
708   // The width of size_t.
709   unsigned sizeWidth = CGF.SizeTy->getBitWidth();
710 
711   // Figure out the cookie size.
712   llvm::APInt cookieSize(sizeWidth,
713                          CalculateCookiePadding(CGF, e).getQuantity());
714 
715   // Emit the array size expression.
716   // We multiply the size of all dimensions for NumElements.
717   // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6.
718   numElements =
719     ConstantEmitter(CGF).tryEmitAbstract(*e->getArraySize(), e->getType());
720   if (!numElements)
721     numElements = CGF.EmitScalarExpr(*e->getArraySize());
722   assert(isa<llvm::IntegerType>(numElements->getType()));
723 
724   // The number of elements can be have an arbitrary integer type;
725   // essentially, we need to multiply it by a constant factor, add a
726   // cookie size, and verify that the result is representable as a
727   // size_t.  That's just a gloss, though, and it's wrong in one
728   // important way: if the count is negative, it's an error even if
729   // the cookie size would bring the total size >= 0.
730   bool isSigned
731     = (*e->getArraySize())->getType()->isSignedIntegerOrEnumerationType();
732   llvm::IntegerType *numElementsType
733     = cast<llvm::IntegerType>(numElements->getType());
734   unsigned numElementsWidth = numElementsType->getBitWidth();
735 
736   // Compute the constant factor.
737   llvm::APInt arraySizeMultiplier(sizeWidth, 1);
738   while (const ConstantArrayType *CAT
739              = CGF.getContext().getAsConstantArrayType(type)) {
740     type = CAT->getElementType();
741     arraySizeMultiplier *= CAT->getSize();
742   }
743 
744   CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
745   llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity());
746   typeSizeMultiplier *= arraySizeMultiplier;
747 
748   // This will be a size_t.
749   llvm::Value *size;
750 
751   // If someone is doing 'new int[42]' there is no need to do a dynamic check.
752   // Don't bloat the -O0 code.
753   if (llvm::ConstantInt *numElementsC =
754         dyn_cast<llvm::ConstantInt>(numElements)) {
755     const llvm::APInt &count = numElementsC->getValue();
756 
757     bool hasAnyOverflow = false;
758 
759     // If 'count' was a negative number, it's an overflow.
760     if (isSigned && count.isNegative())
761       hasAnyOverflow = true;
762 
763     // We want to do all this arithmetic in size_t.  If numElements is
764     // wider than that, check whether it's already too big, and if so,
765     // overflow.
766     else if (numElementsWidth > sizeWidth &&
767              numElementsWidth - sizeWidth > count.countLeadingZeros())
768       hasAnyOverflow = true;
769 
770     // Okay, compute a count at the right width.
771     llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth);
772 
773     // If there is a brace-initializer, we cannot allocate fewer elements than
774     // there are initializers. If we do, that's treated like an overflow.
775     if (adjustedCount.ult(minElements))
776       hasAnyOverflow = true;
777 
778     // Scale numElements by that.  This might overflow, but we don't
779     // care because it only overflows if allocationSize does, too, and
780     // if that overflows then we shouldn't use this.
781     numElements = llvm::ConstantInt::get(CGF.SizeTy,
782                                          adjustedCount * arraySizeMultiplier);
783 
784     // Compute the size before cookie, and track whether it overflowed.
785     bool overflow;
786     llvm::APInt allocationSize
787       = adjustedCount.umul_ov(typeSizeMultiplier, overflow);
788     hasAnyOverflow |= overflow;
789 
790     // Add in the cookie, and check whether it's overflowed.
791     if (cookieSize != 0) {
792       // Save the current size without a cookie.  This shouldn't be
793       // used if there was overflow.
794       sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
795 
796       allocationSize = allocationSize.uadd_ov(cookieSize, overflow);
797       hasAnyOverflow |= overflow;
798     }
799 
800     // On overflow, produce a -1 so operator new will fail.
801     if (hasAnyOverflow) {
802       size = llvm::Constant::getAllOnesValue(CGF.SizeTy);
803     } else {
804       size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
805     }
806 
807   // Otherwise, we might need to use the overflow intrinsics.
808   } else {
809     // There are up to five conditions we need to test for:
810     // 1) if isSigned, we need to check whether numElements is negative;
811     // 2) if numElementsWidth > sizeWidth, we need to check whether
812     //   numElements is larger than something representable in size_t;
813     // 3) if minElements > 0, we need to check whether numElements is smaller
814     //    than that.
815     // 4) we need to compute
816     //      sizeWithoutCookie := numElements * typeSizeMultiplier
817     //    and check whether it overflows; and
818     // 5) if we need a cookie, we need to compute
819     //      size := sizeWithoutCookie + cookieSize
820     //    and check whether it overflows.
821 
822     llvm::Value *hasOverflow = nullptr;
823 
824     // If numElementsWidth > sizeWidth, then one way or another, we're
825     // going to have to do a comparison for (2), and this happens to
826     // take care of (1), too.
827     if (numElementsWidth > sizeWidth) {
828       llvm::APInt threshold(numElementsWidth, 1);
829       threshold <<= sizeWidth;
830 
831       llvm::Value *thresholdV
832         = llvm::ConstantInt::get(numElementsType, threshold);
833 
834       hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV);
835       numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy);
836 
837     // Otherwise, if we're signed, we want to sext up to size_t.
838     } else if (isSigned) {
839       if (numElementsWidth < sizeWidth)
840         numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy);
841 
842       // If there's a non-1 type size multiplier, then we can do the
843       // signedness check at the same time as we do the multiply
844       // because a negative number times anything will cause an
845       // unsigned overflow.  Otherwise, we have to do it here. But at least
846       // in this case, we can subsume the >= minElements check.
847       if (typeSizeMultiplier == 1)
848         hasOverflow = CGF.Builder.CreateICmpSLT(numElements,
849                               llvm::ConstantInt::get(CGF.SizeTy, minElements));
850 
851     // Otherwise, zext up to size_t if necessary.
852     } else if (numElementsWidth < sizeWidth) {
853       numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy);
854     }
855 
856     assert(numElements->getType() == CGF.SizeTy);
857 
858     if (minElements) {
859       // Don't allow allocation of fewer elements than we have initializers.
860       if (!hasOverflow) {
861         hasOverflow = CGF.Builder.CreateICmpULT(numElements,
862                               llvm::ConstantInt::get(CGF.SizeTy, minElements));
863       } else if (numElementsWidth > sizeWidth) {
864         // The other existing overflow subsumes this check.
865         // We do an unsigned comparison, since any signed value < -1 is
866         // taken care of either above or below.
867         hasOverflow = CGF.Builder.CreateOr(hasOverflow,
868                           CGF.Builder.CreateICmpULT(numElements,
869                               llvm::ConstantInt::get(CGF.SizeTy, minElements)));
870       }
871     }
872 
873     size = numElements;
874 
875     // Multiply by the type size if necessary.  This multiplier
876     // includes all the factors for nested arrays.
877     //
878     // This step also causes numElements to be scaled up by the
879     // nested-array factor if necessary.  Overflow on this computation
880     // can be ignored because the result shouldn't be used if
881     // allocation fails.
882     if (typeSizeMultiplier != 1) {
883       llvm::Function *umul_with_overflow
884         = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy);
885 
886       llvm::Value *tsmV =
887         llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier);
888       llvm::Value *result =
889           CGF.Builder.CreateCall(umul_with_overflow, {size, tsmV});
890 
891       llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
892       if (hasOverflow)
893         hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
894       else
895         hasOverflow = overflowed;
896 
897       size = CGF.Builder.CreateExtractValue(result, 0);
898 
899       // Also scale up numElements by the array size multiplier.
900       if (arraySizeMultiplier != 1) {
901         // If the base element type size is 1, then we can re-use the
902         // multiply we just did.
903         if (typeSize.isOne()) {
904           assert(arraySizeMultiplier == typeSizeMultiplier);
905           numElements = size;
906 
907         // Otherwise we need a separate multiply.
908         } else {
909           llvm::Value *asmV =
910             llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier);
911           numElements = CGF.Builder.CreateMul(numElements, asmV);
912         }
913       }
914     } else {
915       // numElements doesn't need to be scaled.
916       assert(arraySizeMultiplier == 1);
917     }
918 
919     // Add in the cookie size if necessary.
920     if (cookieSize != 0) {
921       sizeWithoutCookie = size;
922 
923       llvm::Function *uadd_with_overflow
924         = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy);
925 
926       llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize);
927       llvm::Value *result =
928           CGF.Builder.CreateCall(uadd_with_overflow, {size, cookieSizeV});
929 
930       llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
931       if (hasOverflow)
932         hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
933       else
934         hasOverflow = overflowed;
935 
936       size = CGF.Builder.CreateExtractValue(result, 0);
937     }
938 
939     // If we had any possibility of dynamic overflow, make a select to
940     // overwrite 'size' with an all-ones value, which should cause
941     // operator new to throw.
942     if (hasOverflow)
943       size = CGF.Builder.CreateSelect(hasOverflow,
944                                  llvm::Constant::getAllOnesValue(CGF.SizeTy),
945                                       size);
946   }
947 
948   if (cookieSize == 0)
949     sizeWithoutCookie = size;
950   else
951     assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?");
952 
953   return size;
954 }
955 
956 static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init,
957                                     QualType AllocType, Address NewPtr,
958                                     AggValueSlot::Overlap_t MayOverlap) {
959   // FIXME: Refactor with EmitExprAsInit.
960   switch (CGF.getEvaluationKind(AllocType)) {
961   case TEK_Scalar:
962     CGF.EmitScalarInit(Init, nullptr,
963                        CGF.MakeAddrLValue(NewPtr, AllocType), false);
964     return;
965   case TEK_Complex:
966     CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType),
967                                   /*isInit*/ true);
968     return;
969   case TEK_Aggregate: {
970     AggValueSlot Slot
971       = AggValueSlot::forAddr(NewPtr, AllocType.getQualifiers(),
972                               AggValueSlot::IsDestructed,
973                               AggValueSlot::DoesNotNeedGCBarriers,
974                               AggValueSlot::IsNotAliased,
975                               MayOverlap, AggValueSlot::IsNotZeroed,
976                               AggValueSlot::IsSanitizerChecked);
977     CGF.EmitAggExpr(Init, Slot);
978     return;
979   }
980   }
981   llvm_unreachable("bad evaluation kind");
982 }
983 
984 void CodeGenFunction::EmitNewArrayInitializer(
985     const CXXNewExpr *E, QualType ElementType, llvm::Type *ElementTy,
986     Address BeginPtr, llvm::Value *NumElements,
987     llvm::Value *AllocSizeWithoutCookie) {
988   // If we have a type with trivial initialization and no initializer,
989   // there's nothing to do.
990   if (!E->hasInitializer())
991     return;
992 
993   Address CurPtr = BeginPtr;
994 
995   unsigned InitListElements = 0;
996 
997   const Expr *Init = E->getInitializer();
998   Address EndOfInit = Address::invalid();
999   QualType::DestructionKind DtorKind = ElementType.isDestructedType();
1000   EHScopeStack::stable_iterator Cleanup;
1001   llvm::Instruction *CleanupDominator = nullptr;
1002 
1003   CharUnits ElementSize = getContext().getTypeSizeInChars(ElementType);
1004   CharUnits ElementAlign =
1005     BeginPtr.getAlignment().alignmentOfArrayElement(ElementSize);
1006 
1007   // Attempt to perform zero-initialization using memset.
1008   auto TryMemsetInitialization = [&]() -> bool {
1009     // FIXME: If the type is a pointer-to-data-member under the Itanium ABI,
1010     // we can initialize with a memset to -1.
1011     if (!CGM.getTypes().isZeroInitializable(ElementType))
1012       return false;
1013 
1014     // Optimization: since zero initialization will just set the memory
1015     // to all zeroes, generate a single memset to do it in one shot.
1016 
1017     // Subtract out the size of any elements we've already initialized.
1018     auto *RemainingSize = AllocSizeWithoutCookie;
1019     if (InitListElements) {
1020       // We know this can't overflow; we check this when doing the allocation.
1021       auto *InitializedSize = llvm::ConstantInt::get(
1022           RemainingSize->getType(),
1023           getContext().getTypeSizeInChars(ElementType).getQuantity() *
1024               InitListElements);
1025       RemainingSize = Builder.CreateSub(RemainingSize, InitializedSize);
1026     }
1027 
1028     // Create the memset.
1029     Builder.CreateMemSet(CurPtr, Builder.getInt8(0), RemainingSize, false);
1030     return true;
1031   };
1032 
1033   // If the initializer is an initializer list, first do the explicit elements.
1034   if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
1035     // Initializing from a (braced) string literal is a special case; the init
1036     // list element does not initialize a (single) array element.
1037     if (ILE->isStringLiteralInit()) {
1038       // Initialize the initial portion of length equal to that of the string
1039       // literal. The allocation must be for at least this much; we emitted a
1040       // check for that earlier.
1041       AggValueSlot Slot =
1042           AggValueSlot::forAddr(CurPtr, ElementType.getQualifiers(),
1043                                 AggValueSlot::IsDestructed,
1044                                 AggValueSlot::DoesNotNeedGCBarriers,
1045                                 AggValueSlot::IsNotAliased,
1046                                 AggValueSlot::DoesNotOverlap,
1047                                 AggValueSlot::IsNotZeroed,
1048                                 AggValueSlot::IsSanitizerChecked);
1049       EmitAggExpr(ILE->getInit(0), Slot);
1050 
1051       // Move past these elements.
1052       InitListElements =
1053           cast<ConstantArrayType>(ILE->getType()->getAsArrayTypeUnsafe())
1054               ->getSize().getZExtValue();
1055       CurPtr =
1056           Address(Builder.CreateInBoundsGEP(CurPtr.getElementType(),
1057                                             CurPtr.getPointer(),
1058                                             Builder.getSize(InitListElements),
1059                                             "string.init.end"),
1060                   CurPtr.getAlignment().alignmentAtOffset(InitListElements *
1061                                                           ElementSize));
1062 
1063       // Zero out the rest, if any remain.
1064       llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements);
1065       if (!ConstNum || !ConstNum->equalsInt(InitListElements)) {
1066         bool OK = TryMemsetInitialization();
1067         (void)OK;
1068         assert(OK && "couldn't memset character type?");
1069       }
1070       return;
1071     }
1072 
1073     InitListElements = ILE->getNumInits();
1074 
1075     // If this is a multi-dimensional array new, we will initialize multiple
1076     // elements with each init list element.
1077     QualType AllocType = E->getAllocatedType();
1078     if (const ConstantArrayType *CAT = dyn_cast_or_null<ConstantArrayType>(
1079             AllocType->getAsArrayTypeUnsafe())) {
1080       ElementTy = ConvertTypeForMem(AllocType);
1081       CurPtr = Builder.CreateElementBitCast(CurPtr, ElementTy);
1082       InitListElements *= getContext().getConstantArrayElementCount(CAT);
1083     }
1084 
1085     // Enter a partial-destruction Cleanup if necessary.
1086     if (needsEHCleanup(DtorKind)) {
1087       // In principle we could tell the Cleanup where we are more
1088       // directly, but the control flow can get so varied here that it
1089       // would actually be quite complex.  Therefore we go through an
1090       // alloca.
1091       EndOfInit = CreateTempAlloca(BeginPtr.getType(), getPointerAlign(),
1092                                    "array.init.end");
1093       CleanupDominator = Builder.CreateStore(BeginPtr.getPointer(), EndOfInit);
1094       pushIrregularPartialArrayCleanup(BeginPtr.getPointer(), EndOfInit,
1095                                        ElementType, ElementAlign,
1096                                        getDestroyer(DtorKind));
1097       Cleanup = EHStack.stable_begin();
1098     }
1099 
1100     CharUnits StartAlign = CurPtr.getAlignment();
1101     for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) {
1102       // Tell the cleanup that it needs to destroy up to this
1103       // element.  TODO: some of these stores can be trivially
1104       // observed to be unnecessary.
1105       if (EndOfInit.isValid()) {
1106         auto FinishedPtr =
1107           Builder.CreateBitCast(CurPtr.getPointer(), BeginPtr.getType());
1108         Builder.CreateStore(FinishedPtr, EndOfInit);
1109       }
1110       // FIXME: If the last initializer is an incomplete initializer list for
1111       // an array, and we have an array filler, we can fold together the two
1112       // initialization loops.
1113       StoreAnyExprIntoOneUnit(*this, ILE->getInit(i),
1114                               ILE->getInit(i)->getType(), CurPtr,
1115                               AggValueSlot::DoesNotOverlap);
1116       CurPtr = Address(Builder.CreateInBoundsGEP(CurPtr.getElementType(),
1117                                                  CurPtr.getPointer(),
1118                                                  Builder.getSize(1),
1119                                                  "array.exp.next"),
1120                        StartAlign.alignmentAtOffset((i + 1) * ElementSize));
1121     }
1122 
1123     // The remaining elements are filled with the array filler expression.
1124     Init = ILE->getArrayFiller();
1125 
1126     // Extract the initializer for the individual array elements by pulling
1127     // out the array filler from all the nested initializer lists. This avoids
1128     // generating a nested loop for the initialization.
1129     while (Init && Init->getType()->isConstantArrayType()) {
1130       auto *SubILE = dyn_cast<InitListExpr>(Init);
1131       if (!SubILE)
1132         break;
1133       assert(SubILE->getNumInits() == 0 && "explicit inits in array filler?");
1134       Init = SubILE->getArrayFiller();
1135     }
1136 
1137     // Switch back to initializing one base element at a time.
1138     CurPtr = Builder.CreateBitCast(CurPtr, BeginPtr.getType());
1139   }
1140 
1141   // If all elements have already been initialized, skip any further
1142   // initialization.
1143   llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements);
1144   if (ConstNum && ConstNum->getZExtValue() <= InitListElements) {
1145     // If there was a Cleanup, deactivate it.
1146     if (CleanupDominator)
1147       DeactivateCleanupBlock(Cleanup, CleanupDominator);
1148     return;
1149   }
1150 
1151   assert(Init && "have trailing elements to initialize but no initializer");
1152 
1153   // If this is a constructor call, try to optimize it out, and failing that
1154   // emit a single loop to initialize all remaining elements.
1155   if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init)) {
1156     CXXConstructorDecl *Ctor = CCE->getConstructor();
1157     if (Ctor->isTrivial()) {
1158       // If new expression did not specify value-initialization, then there
1159       // is no initialization.
1160       if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty())
1161         return;
1162 
1163       if (TryMemsetInitialization())
1164         return;
1165     }
1166 
1167     // Store the new Cleanup position for irregular Cleanups.
1168     //
1169     // FIXME: Share this cleanup with the constructor call emission rather than
1170     // having it create a cleanup of its own.
1171     if (EndOfInit.isValid())
1172       Builder.CreateStore(CurPtr.getPointer(), EndOfInit);
1173 
1174     // Emit a constructor call loop to initialize the remaining elements.
1175     if (InitListElements)
1176       NumElements = Builder.CreateSub(
1177           NumElements,
1178           llvm::ConstantInt::get(NumElements->getType(), InitListElements));
1179     EmitCXXAggrConstructorCall(Ctor, NumElements, CurPtr, CCE,
1180                                /*NewPointerIsChecked*/true,
1181                                CCE->requiresZeroInitialization());
1182     return;
1183   }
1184 
1185   // If this is value-initialization, we can usually use memset.
1186   ImplicitValueInitExpr IVIE(ElementType);
1187   if (isa<ImplicitValueInitExpr>(Init)) {
1188     if (TryMemsetInitialization())
1189       return;
1190 
1191     // Switch to an ImplicitValueInitExpr for the element type. This handles
1192     // only one case: multidimensional array new of pointers to members. In
1193     // all other cases, we already have an initializer for the array element.
1194     Init = &IVIE;
1195   }
1196 
1197   // At this point we should have found an initializer for the individual
1198   // elements of the array.
1199   assert(getContext().hasSameUnqualifiedType(ElementType, Init->getType()) &&
1200          "got wrong type of element to initialize");
1201 
1202   // If we have an empty initializer list, we can usually use memset.
1203   if (auto *ILE = dyn_cast<InitListExpr>(Init))
1204     if (ILE->getNumInits() == 0 && TryMemsetInitialization())
1205       return;
1206 
1207   // If we have a struct whose every field is value-initialized, we can
1208   // usually use memset.
1209   if (auto *ILE = dyn_cast<InitListExpr>(Init)) {
1210     if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
1211       if (RType->getDecl()->isStruct()) {
1212         unsigned NumElements = 0;
1213         if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RType->getDecl()))
1214           NumElements = CXXRD->getNumBases();
1215         for (auto *Field : RType->getDecl()->fields())
1216           if (!Field->isUnnamedBitfield())
1217             ++NumElements;
1218         // FIXME: Recurse into nested InitListExprs.
1219         if (ILE->getNumInits() == NumElements)
1220           for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
1221             if (!isa<ImplicitValueInitExpr>(ILE->getInit(i)))
1222               --NumElements;
1223         if (ILE->getNumInits() == NumElements && TryMemsetInitialization())
1224           return;
1225       }
1226     }
1227   }
1228 
1229   // Create the loop blocks.
1230   llvm::BasicBlock *EntryBB = Builder.GetInsertBlock();
1231   llvm::BasicBlock *LoopBB = createBasicBlock("new.loop");
1232   llvm::BasicBlock *ContBB = createBasicBlock("new.loop.end");
1233 
1234   // Find the end of the array, hoisted out of the loop.
1235   llvm::Value *EndPtr =
1236     Builder.CreateInBoundsGEP(BeginPtr.getElementType(), BeginPtr.getPointer(),
1237                               NumElements, "array.end");
1238 
1239   // If the number of elements isn't constant, we have to now check if there is
1240   // anything left to initialize.
1241   if (!ConstNum) {
1242     llvm::Value *IsEmpty =
1243       Builder.CreateICmpEQ(CurPtr.getPointer(), EndPtr, "array.isempty");
1244     Builder.CreateCondBr(IsEmpty, ContBB, LoopBB);
1245   }
1246 
1247   // Enter the loop.
1248   EmitBlock(LoopBB);
1249 
1250   // Set up the current-element phi.
1251   llvm::PHINode *CurPtrPhi =
1252     Builder.CreatePHI(CurPtr.getType(), 2, "array.cur");
1253   CurPtrPhi->addIncoming(CurPtr.getPointer(), EntryBB);
1254 
1255   CurPtr = Address(CurPtrPhi, ElementAlign);
1256 
1257   // Store the new Cleanup position for irregular Cleanups.
1258   if (EndOfInit.isValid())
1259     Builder.CreateStore(CurPtr.getPointer(), EndOfInit);
1260 
1261   // Enter a partial-destruction Cleanup if necessary.
1262   if (!CleanupDominator && needsEHCleanup(DtorKind)) {
1263     pushRegularPartialArrayCleanup(BeginPtr.getPointer(), CurPtr.getPointer(),
1264                                    ElementType, ElementAlign,
1265                                    getDestroyer(DtorKind));
1266     Cleanup = EHStack.stable_begin();
1267     CleanupDominator = Builder.CreateUnreachable();
1268   }
1269 
1270   // Emit the initializer into this element.
1271   StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr,
1272                           AggValueSlot::DoesNotOverlap);
1273 
1274   // Leave the Cleanup if we entered one.
1275   if (CleanupDominator) {
1276     DeactivateCleanupBlock(Cleanup, CleanupDominator);
1277     CleanupDominator->eraseFromParent();
1278   }
1279 
1280   // Advance to the next element by adjusting the pointer type as necessary.
1281   llvm::Value *NextPtr =
1282     Builder.CreateConstInBoundsGEP1_32(ElementTy, CurPtr.getPointer(), 1,
1283                                        "array.next");
1284 
1285   // Check whether we've gotten to the end of the array and, if so,
1286   // exit the loop.
1287   llvm::Value *IsEnd = Builder.CreateICmpEQ(NextPtr, EndPtr, "array.atend");
1288   Builder.CreateCondBr(IsEnd, ContBB, LoopBB);
1289   CurPtrPhi->addIncoming(NextPtr, Builder.GetInsertBlock());
1290 
1291   EmitBlock(ContBB);
1292 }
1293 
1294 static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E,
1295                                QualType ElementType, llvm::Type *ElementTy,
1296                                Address NewPtr, llvm::Value *NumElements,
1297                                llvm::Value *AllocSizeWithoutCookie) {
1298   ApplyDebugLocation DL(CGF, E);
1299   if (E->isArray())
1300     CGF.EmitNewArrayInitializer(E, ElementType, ElementTy, NewPtr, NumElements,
1301                                 AllocSizeWithoutCookie);
1302   else if (const Expr *Init = E->getInitializer())
1303     StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr,
1304                             AggValueSlot::DoesNotOverlap);
1305 }
1306 
1307 /// Emit a call to an operator new or operator delete function, as implicitly
1308 /// created by new-expressions and delete-expressions.
1309 static RValue EmitNewDeleteCall(CodeGenFunction &CGF,
1310                                 const FunctionDecl *CalleeDecl,
1311                                 const FunctionProtoType *CalleeType,
1312                                 const CallArgList &Args) {
1313   llvm::CallBase *CallOrInvoke;
1314   llvm::Constant *CalleePtr = CGF.CGM.GetAddrOfFunction(CalleeDecl);
1315   CGCallee Callee = CGCallee::forDirect(CalleePtr, GlobalDecl(CalleeDecl));
1316   RValue RV =
1317       CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall(
1318                        Args, CalleeType, /*ChainCall=*/false),
1319                    Callee, ReturnValueSlot(), Args, &CallOrInvoke);
1320 
1321   /// C++1y [expr.new]p10:
1322   ///   [In a new-expression,] an implementation is allowed to omit a call
1323   ///   to a replaceable global allocation function.
1324   ///
1325   /// We model such elidable calls with the 'builtin' attribute.
1326   llvm::Function *Fn = dyn_cast<llvm::Function>(CalleePtr);
1327   if (CalleeDecl->isReplaceableGlobalAllocationFunction() &&
1328       Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) {
1329     CallOrInvoke->addAttribute(llvm::AttributeList::FunctionIndex,
1330                                llvm::Attribute::Builtin);
1331   }
1332 
1333   return RV;
1334 }
1335 
1336 RValue CodeGenFunction::EmitBuiltinNewDeleteCall(const FunctionProtoType *Type,
1337                                                  const CallExpr *TheCall,
1338                                                  bool IsDelete) {
1339   CallArgList Args;
1340   EmitCallArgs(Args, Type, TheCall->arguments());
1341   // Find the allocation or deallocation function that we're calling.
1342   ASTContext &Ctx = getContext();
1343   DeclarationName Name = Ctx.DeclarationNames
1344       .getCXXOperatorName(IsDelete ? OO_Delete : OO_New);
1345 
1346   for (auto *Decl : Ctx.getTranslationUnitDecl()->lookup(Name))
1347     if (auto *FD = dyn_cast<FunctionDecl>(Decl))
1348       if (Ctx.hasSameType(FD->getType(), QualType(Type, 0)))
1349         return EmitNewDeleteCall(*this, FD, Type, Args);
1350   llvm_unreachable("predeclared global operator new/delete is missing");
1351 }
1352 
1353 namespace {
1354 /// The parameters to pass to a usual operator delete.
1355 struct UsualDeleteParams {
1356   bool DestroyingDelete = false;
1357   bool Size = false;
1358   bool Alignment = false;
1359 };
1360 }
1361 
1362 static UsualDeleteParams getUsualDeleteParams(const FunctionDecl *FD) {
1363   UsualDeleteParams Params;
1364 
1365   const FunctionProtoType *FPT = FD->getType()->castAs<FunctionProtoType>();
1366   auto AI = FPT->param_type_begin(), AE = FPT->param_type_end();
1367 
1368   // The first argument is always a void*.
1369   ++AI;
1370 
1371   // The next parameter may be a std::destroying_delete_t.
1372   if (FD->isDestroyingOperatorDelete()) {
1373     Params.DestroyingDelete = true;
1374     assert(AI != AE);
1375     ++AI;
1376   }
1377 
1378   // Figure out what other parameters we should be implicitly passing.
1379   if (AI != AE && (*AI)->isIntegerType()) {
1380     Params.Size = true;
1381     ++AI;
1382   }
1383 
1384   if (AI != AE && (*AI)->isAlignValT()) {
1385     Params.Alignment = true;
1386     ++AI;
1387   }
1388 
1389   assert(AI == AE && "unexpected usual deallocation function parameter");
1390   return Params;
1391 }
1392 
1393 namespace {
1394   /// A cleanup to call the given 'operator delete' function upon abnormal
1395   /// exit from a new expression. Templated on a traits type that deals with
1396   /// ensuring that the arguments dominate the cleanup if necessary.
1397   template<typename Traits>
1398   class CallDeleteDuringNew final : public EHScopeStack::Cleanup {
1399     /// Type used to hold llvm::Value*s.
1400     typedef typename Traits::ValueTy ValueTy;
1401     /// Type used to hold RValues.
1402     typedef typename Traits::RValueTy RValueTy;
1403     struct PlacementArg {
1404       RValueTy ArgValue;
1405       QualType ArgType;
1406     };
1407 
1408     unsigned NumPlacementArgs : 31;
1409     unsigned PassAlignmentToPlacementDelete : 1;
1410     const FunctionDecl *OperatorDelete;
1411     ValueTy Ptr;
1412     ValueTy AllocSize;
1413     CharUnits AllocAlign;
1414 
1415     PlacementArg *getPlacementArgs() {
1416       return reinterpret_cast<PlacementArg *>(this + 1);
1417     }
1418 
1419   public:
1420     static size_t getExtraSize(size_t NumPlacementArgs) {
1421       return NumPlacementArgs * sizeof(PlacementArg);
1422     }
1423 
1424     CallDeleteDuringNew(size_t NumPlacementArgs,
1425                         const FunctionDecl *OperatorDelete, ValueTy Ptr,
1426                         ValueTy AllocSize, bool PassAlignmentToPlacementDelete,
1427                         CharUnits AllocAlign)
1428       : NumPlacementArgs(NumPlacementArgs),
1429         PassAlignmentToPlacementDelete(PassAlignmentToPlacementDelete),
1430         OperatorDelete(OperatorDelete), Ptr(Ptr), AllocSize(AllocSize),
1431         AllocAlign(AllocAlign) {}
1432 
1433     void setPlacementArg(unsigned I, RValueTy Arg, QualType Type) {
1434       assert(I < NumPlacementArgs && "index out of range");
1435       getPlacementArgs()[I] = {Arg, Type};
1436     }
1437 
1438     void Emit(CodeGenFunction &CGF, Flags flags) override {
1439       const auto *FPT = OperatorDelete->getType()->castAs<FunctionProtoType>();
1440       CallArgList DeleteArgs;
1441 
1442       // The first argument is always a void* (or C* for a destroying operator
1443       // delete for class type C).
1444       DeleteArgs.add(Traits::get(CGF, Ptr), FPT->getParamType(0));
1445 
1446       // Figure out what other parameters we should be implicitly passing.
1447       UsualDeleteParams Params;
1448       if (NumPlacementArgs) {
1449         // A placement deallocation function is implicitly passed an alignment
1450         // if the placement allocation function was, but is never passed a size.
1451         Params.Alignment = PassAlignmentToPlacementDelete;
1452       } else {
1453         // For a non-placement new-expression, 'operator delete' can take a
1454         // size and/or an alignment if it has the right parameters.
1455         Params = getUsualDeleteParams(OperatorDelete);
1456       }
1457 
1458       assert(!Params.DestroyingDelete &&
1459              "should not call destroying delete in a new-expression");
1460 
1461       // The second argument can be a std::size_t (for non-placement delete).
1462       if (Params.Size)
1463         DeleteArgs.add(Traits::get(CGF, AllocSize),
1464                        CGF.getContext().getSizeType());
1465 
1466       // The next (second or third) argument can be a std::align_val_t, which
1467       // is an enum whose underlying type is std::size_t.
1468       // FIXME: Use the right type as the parameter type. Note that in a call
1469       // to operator delete(size_t, ...), we may not have it available.
1470       if (Params.Alignment)
1471         DeleteArgs.add(RValue::get(llvm::ConstantInt::get(
1472                            CGF.SizeTy, AllocAlign.getQuantity())),
1473                        CGF.getContext().getSizeType());
1474 
1475       // Pass the rest of the arguments, which must match exactly.
1476       for (unsigned I = 0; I != NumPlacementArgs; ++I) {
1477         auto Arg = getPlacementArgs()[I];
1478         DeleteArgs.add(Traits::get(CGF, Arg.ArgValue), Arg.ArgType);
1479       }
1480 
1481       // Call 'operator delete'.
1482       EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs);
1483     }
1484   };
1485 }
1486 
1487 /// Enter a cleanup to call 'operator delete' if the initializer in a
1488 /// new-expression throws.
1489 static void EnterNewDeleteCleanup(CodeGenFunction &CGF,
1490                                   const CXXNewExpr *E,
1491                                   Address NewPtr,
1492                                   llvm::Value *AllocSize,
1493                                   CharUnits AllocAlign,
1494                                   const CallArgList &NewArgs) {
1495   unsigned NumNonPlacementArgs = E->passAlignment() ? 2 : 1;
1496 
1497   // If we're not inside a conditional branch, then the cleanup will
1498   // dominate and we can do the easier (and more efficient) thing.
1499   if (!CGF.isInConditionalBranch()) {
1500     struct DirectCleanupTraits {
1501       typedef llvm::Value *ValueTy;
1502       typedef RValue RValueTy;
1503       static RValue get(CodeGenFunction &, ValueTy V) { return RValue::get(V); }
1504       static RValue get(CodeGenFunction &, RValueTy V) { return V; }
1505     };
1506 
1507     typedef CallDeleteDuringNew<DirectCleanupTraits> DirectCleanup;
1508 
1509     DirectCleanup *Cleanup = CGF.EHStack
1510       .pushCleanupWithExtra<DirectCleanup>(EHCleanup,
1511                                            E->getNumPlacementArgs(),
1512                                            E->getOperatorDelete(),
1513                                            NewPtr.getPointer(),
1514                                            AllocSize,
1515                                            E->passAlignment(),
1516                                            AllocAlign);
1517     for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) {
1518       auto &Arg = NewArgs[I + NumNonPlacementArgs];
1519       Cleanup->setPlacementArg(I, Arg.getRValue(CGF), Arg.Ty);
1520     }
1521 
1522     return;
1523   }
1524 
1525   // Otherwise, we need to save all this stuff.
1526   DominatingValue<RValue>::saved_type SavedNewPtr =
1527     DominatingValue<RValue>::save(CGF, RValue::get(NewPtr.getPointer()));
1528   DominatingValue<RValue>::saved_type SavedAllocSize =
1529     DominatingValue<RValue>::save(CGF, RValue::get(AllocSize));
1530 
1531   struct ConditionalCleanupTraits {
1532     typedef DominatingValue<RValue>::saved_type ValueTy;
1533     typedef DominatingValue<RValue>::saved_type RValueTy;
1534     static RValue get(CodeGenFunction &CGF, ValueTy V) {
1535       return V.restore(CGF);
1536     }
1537   };
1538   typedef CallDeleteDuringNew<ConditionalCleanupTraits> ConditionalCleanup;
1539 
1540   ConditionalCleanup *Cleanup = CGF.EHStack
1541     .pushCleanupWithExtra<ConditionalCleanup>(EHCleanup,
1542                                               E->getNumPlacementArgs(),
1543                                               E->getOperatorDelete(),
1544                                               SavedNewPtr,
1545                                               SavedAllocSize,
1546                                               E->passAlignment(),
1547                                               AllocAlign);
1548   for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) {
1549     auto &Arg = NewArgs[I + NumNonPlacementArgs];
1550     Cleanup->setPlacementArg(
1551         I, DominatingValue<RValue>::save(CGF, Arg.getRValue(CGF)), Arg.Ty);
1552   }
1553 
1554   CGF.initFullExprCleanup();
1555 }
1556 
1557 llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) {
1558   // The element type being allocated.
1559   QualType allocType = getContext().getBaseElementType(E->getAllocatedType());
1560 
1561   // 1. Build a call to the allocation function.
1562   FunctionDecl *allocator = E->getOperatorNew();
1563 
1564   // If there is a brace-initializer, cannot allocate fewer elements than inits.
1565   unsigned minElements = 0;
1566   if (E->isArray() && E->hasInitializer()) {
1567     const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer());
1568     if (ILE && ILE->isStringLiteralInit())
1569       minElements =
1570           cast<ConstantArrayType>(ILE->getType()->getAsArrayTypeUnsafe())
1571               ->getSize().getZExtValue();
1572     else if (ILE)
1573       minElements = ILE->getNumInits();
1574   }
1575 
1576   llvm::Value *numElements = nullptr;
1577   llvm::Value *allocSizeWithoutCookie = nullptr;
1578   llvm::Value *allocSize =
1579     EmitCXXNewAllocSize(*this, E, minElements, numElements,
1580                         allocSizeWithoutCookie);
1581   CharUnits allocAlign = getContext().getPreferredTypeAlignInChars(allocType);
1582 
1583   // Emit the allocation call.  If the allocator is a global placement
1584   // operator, just "inline" it directly.
1585   Address allocation = Address::invalid();
1586   CallArgList allocatorArgs;
1587   if (allocator->isReservedGlobalPlacementOperator()) {
1588     assert(E->getNumPlacementArgs() == 1);
1589     const Expr *arg = *E->placement_arguments().begin();
1590 
1591     LValueBaseInfo BaseInfo;
1592     allocation = EmitPointerWithAlignment(arg, &BaseInfo);
1593 
1594     // The pointer expression will, in many cases, be an opaque void*.
1595     // In these cases, discard the computed alignment and use the
1596     // formal alignment of the allocated type.
1597     if (BaseInfo.getAlignmentSource() != AlignmentSource::Decl)
1598       allocation = Address(allocation.getPointer(), allocAlign);
1599 
1600     // Set up allocatorArgs for the call to operator delete if it's not
1601     // the reserved global operator.
1602     if (E->getOperatorDelete() &&
1603         !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
1604       allocatorArgs.add(RValue::get(allocSize), getContext().getSizeType());
1605       allocatorArgs.add(RValue::get(allocation.getPointer()), arg->getType());
1606     }
1607 
1608   } else {
1609     const FunctionProtoType *allocatorType =
1610       allocator->getType()->castAs<FunctionProtoType>();
1611     unsigned ParamsToSkip = 0;
1612 
1613     // The allocation size is the first argument.
1614     QualType sizeType = getContext().getSizeType();
1615     allocatorArgs.add(RValue::get(allocSize), sizeType);
1616     ++ParamsToSkip;
1617 
1618     if (allocSize != allocSizeWithoutCookie) {
1619       CharUnits cookieAlign = getSizeAlign(); // FIXME: Ask the ABI.
1620       allocAlign = std::max(allocAlign, cookieAlign);
1621     }
1622 
1623     // The allocation alignment may be passed as the second argument.
1624     if (E->passAlignment()) {
1625       QualType AlignValT = sizeType;
1626       if (allocatorType->getNumParams() > 1) {
1627         AlignValT = allocatorType->getParamType(1);
1628         assert(getContext().hasSameUnqualifiedType(
1629                    AlignValT->castAs<EnumType>()->getDecl()->getIntegerType(),
1630                    sizeType) &&
1631                "wrong type for alignment parameter");
1632         ++ParamsToSkip;
1633       } else {
1634         // Corner case, passing alignment to 'operator new(size_t, ...)'.
1635         assert(allocator->isVariadic() && "can't pass alignment to allocator");
1636       }
1637       allocatorArgs.add(
1638           RValue::get(llvm::ConstantInt::get(SizeTy, allocAlign.getQuantity())),
1639           AlignValT);
1640     }
1641 
1642     // FIXME: Why do we not pass a CalleeDecl here?
1643     EmitCallArgs(allocatorArgs, allocatorType, E->placement_arguments(),
1644                  /*AC*/AbstractCallee(), /*ParamsToSkip*/ParamsToSkip);
1645 
1646     RValue RV =
1647       EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs);
1648 
1649     // Set !heapallocsite metadata on the call to operator new.
1650     if (getDebugInfo())
1651       if (auto *newCall = dyn_cast<llvm::CallBase>(RV.getScalarVal()))
1652         getDebugInfo()->addHeapAllocSiteMetadata(newCall, allocType,
1653                                                  E->getExprLoc());
1654 
1655     // If this was a call to a global replaceable allocation function that does
1656     // not take an alignment argument, the allocator is known to produce
1657     // storage that's suitably aligned for any object that fits, up to a known
1658     // threshold. Otherwise assume it's suitably aligned for the allocated type.
1659     CharUnits allocationAlign = allocAlign;
1660     if (!E->passAlignment() &&
1661         allocator->isReplaceableGlobalAllocationFunction()) {
1662       unsigned AllocatorAlign = llvm::PowerOf2Floor(std::min<uint64_t>(
1663           Target.getNewAlign(), getContext().getTypeSize(allocType)));
1664       allocationAlign = std::max(
1665           allocationAlign, getContext().toCharUnitsFromBits(AllocatorAlign));
1666     }
1667 
1668     allocation = Address(RV.getScalarVal(), allocationAlign);
1669   }
1670 
1671   // Emit a null check on the allocation result if the allocation
1672   // function is allowed to return null (because it has a non-throwing
1673   // exception spec or is the reserved placement new) and we have an
1674   // interesting initializer will be running sanitizers on the initialization.
1675   bool nullCheck = E->shouldNullCheckAllocation() &&
1676                    (!allocType.isPODType(getContext()) || E->hasInitializer() ||
1677                     sanitizePerformTypeCheck());
1678 
1679   llvm::BasicBlock *nullCheckBB = nullptr;
1680   llvm::BasicBlock *contBB = nullptr;
1681 
1682   // The null-check means that the initializer is conditionally
1683   // evaluated.
1684   ConditionalEvaluation conditional(*this);
1685 
1686   if (nullCheck) {
1687     conditional.begin(*this);
1688 
1689     nullCheckBB = Builder.GetInsertBlock();
1690     llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull");
1691     contBB = createBasicBlock("new.cont");
1692 
1693     llvm::Value *isNull =
1694       Builder.CreateIsNull(allocation.getPointer(), "new.isnull");
1695     Builder.CreateCondBr(isNull, contBB, notNullBB);
1696     EmitBlock(notNullBB);
1697   }
1698 
1699   // If there's an operator delete, enter a cleanup to call it if an
1700   // exception is thrown.
1701   EHScopeStack::stable_iterator operatorDeleteCleanup;
1702   llvm::Instruction *cleanupDominator = nullptr;
1703   if (E->getOperatorDelete() &&
1704       !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
1705     EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocAlign,
1706                           allocatorArgs);
1707     operatorDeleteCleanup = EHStack.stable_begin();
1708     cleanupDominator = Builder.CreateUnreachable();
1709   }
1710 
1711   assert((allocSize == allocSizeWithoutCookie) ==
1712          CalculateCookiePadding(*this, E).isZero());
1713   if (allocSize != allocSizeWithoutCookie) {
1714     assert(E->isArray());
1715     allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation,
1716                                                        numElements,
1717                                                        E, allocType);
1718   }
1719 
1720   llvm::Type *elementTy = ConvertTypeForMem(allocType);
1721   Address result = Builder.CreateElementBitCast(allocation, elementTy);
1722 
1723   // Passing pointer through launder.invariant.group to avoid propagation of
1724   // vptrs information which may be included in previous type.
1725   // To not break LTO with different optimizations levels, we do it regardless
1726   // of optimization level.
1727   if (CGM.getCodeGenOpts().StrictVTablePointers &&
1728       allocator->isReservedGlobalPlacementOperator())
1729     result = Address(Builder.CreateLaunderInvariantGroup(result.getPointer()),
1730                      result.getAlignment());
1731 
1732   // Emit sanitizer checks for pointer value now, so that in the case of an
1733   // array it was checked only once and not at each constructor call. We may
1734   // have already checked that the pointer is non-null.
1735   // FIXME: If we have an array cookie and a potentially-throwing allocator,
1736   // we'll null check the wrong pointer here.
1737   SanitizerSet SkippedChecks;
1738   SkippedChecks.set(SanitizerKind::Null, nullCheck);
1739   EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall,
1740                 E->getAllocatedTypeSourceInfo()->getTypeLoc().getBeginLoc(),
1741                 result.getPointer(), allocType, result.getAlignment(),
1742                 SkippedChecks, numElements);
1743 
1744   EmitNewInitializer(*this, E, allocType, elementTy, result, numElements,
1745                      allocSizeWithoutCookie);
1746   if (E->isArray()) {
1747     // NewPtr is a pointer to the base element type.  If we're
1748     // allocating an array of arrays, we'll need to cast back to the
1749     // array pointer type.
1750     llvm::Type *resultType = ConvertTypeForMem(E->getType());
1751     if (result.getType() != resultType)
1752       result = Builder.CreateBitCast(result, resultType);
1753   }
1754 
1755   // Deactivate the 'operator delete' cleanup if we finished
1756   // initialization.
1757   if (operatorDeleteCleanup.isValid()) {
1758     DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator);
1759     cleanupDominator->eraseFromParent();
1760   }
1761 
1762   llvm::Value *resultPtr = result.getPointer();
1763   if (nullCheck) {
1764     conditional.end(*this);
1765 
1766     llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
1767     EmitBlock(contBB);
1768 
1769     llvm::PHINode *PHI = Builder.CreatePHI(resultPtr->getType(), 2);
1770     PHI->addIncoming(resultPtr, notNullBB);
1771     PHI->addIncoming(llvm::Constant::getNullValue(resultPtr->getType()),
1772                      nullCheckBB);
1773 
1774     resultPtr = PHI;
1775   }
1776 
1777   return resultPtr;
1778 }
1779 
1780 void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD,
1781                                      llvm::Value *Ptr, QualType DeleteTy,
1782                                      llvm::Value *NumElements,
1783                                      CharUnits CookieSize) {
1784   assert((!NumElements && CookieSize.isZero()) ||
1785          DeleteFD->getOverloadedOperator() == OO_Array_Delete);
1786 
1787   const auto *DeleteFTy = DeleteFD->getType()->castAs<FunctionProtoType>();
1788   CallArgList DeleteArgs;
1789 
1790   auto Params = getUsualDeleteParams(DeleteFD);
1791   auto ParamTypeIt = DeleteFTy->param_type_begin();
1792 
1793   // Pass the pointer itself.
1794   QualType ArgTy = *ParamTypeIt++;
1795   llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy));
1796   DeleteArgs.add(RValue::get(DeletePtr), ArgTy);
1797 
1798   // Pass the std::destroying_delete tag if present.
1799   llvm::AllocaInst *DestroyingDeleteTag = nullptr;
1800   if (Params.DestroyingDelete) {
1801     QualType DDTag = *ParamTypeIt++;
1802     llvm::Type *Ty = getTypes().ConvertType(DDTag);
1803     CharUnits Align = CGM.getNaturalTypeAlignment(DDTag);
1804     DestroyingDeleteTag = CreateTempAlloca(Ty, "destroying.delete.tag");
1805     DestroyingDeleteTag->setAlignment(Align.getAsAlign());
1806     DeleteArgs.add(RValue::getAggregate(Address(DestroyingDeleteTag, Align)), DDTag);
1807   }
1808 
1809   // Pass the size if the delete function has a size_t parameter.
1810   if (Params.Size) {
1811     QualType SizeType = *ParamTypeIt++;
1812     CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy);
1813     llvm::Value *Size = llvm::ConstantInt::get(ConvertType(SizeType),
1814                                                DeleteTypeSize.getQuantity());
1815 
1816     // For array new, multiply by the number of elements.
1817     if (NumElements)
1818       Size = Builder.CreateMul(Size, NumElements);
1819 
1820     // If there is a cookie, add the cookie size.
1821     if (!CookieSize.isZero())
1822       Size = Builder.CreateAdd(
1823           Size, llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity()));
1824 
1825     DeleteArgs.add(RValue::get(Size), SizeType);
1826   }
1827 
1828   // Pass the alignment if the delete function has an align_val_t parameter.
1829   if (Params.Alignment) {
1830     QualType AlignValType = *ParamTypeIt++;
1831     CharUnits DeleteTypeAlign =
1832         getContext().toCharUnitsFromBits(getContext().getTypeAlignIfKnown(
1833             DeleteTy, true /* NeedsPreferredAlignment */));
1834     llvm::Value *Align = llvm::ConstantInt::get(ConvertType(AlignValType),
1835                                                 DeleteTypeAlign.getQuantity());
1836     DeleteArgs.add(RValue::get(Align), AlignValType);
1837   }
1838 
1839   assert(ParamTypeIt == DeleteFTy->param_type_end() &&
1840          "unknown parameter to usual delete function");
1841 
1842   // Emit the call to delete.
1843   EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs);
1844 
1845   // If call argument lowering didn't use the destroying_delete_t alloca,
1846   // remove it again.
1847   if (DestroyingDeleteTag && DestroyingDeleteTag->use_empty())
1848     DestroyingDeleteTag->eraseFromParent();
1849 }
1850 
1851 namespace {
1852   /// Calls the given 'operator delete' on a single object.
1853   struct CallObjectDelete final : EHScopeStack::Cleanup {
1854     llvm::Value *Ptr;
1855     const FunctionDecl *OperatorDelete;
1856     QualType ElementType;
1857 
1858     CallObjectDelete(llvm::Value *Ptr,
1859                      const FunctionDecl *OperatorDelete,
1860                      QualType ElementType)
1861       : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {}
1862 
1863     void Emit(CodeGenFunction &CGF, Flags flags) override {
1864       CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType);
1865     }
1866   };
1867 }
1868 
1869 void
1870 CodeGenFunction::pushCallObjectDeleteCleanup(const FunctionDecl *OperatorDelete,
1871                                              llvm::Value *CompletePtr,
1872                                              QualType ElementType) {
1873   EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, CompletePtr,
1874                                         OperatorDelete, ElementType);
1875 }
1876 
1877 /// Emit the code for deleting a single object with a destroying operator
1878 /// delete. If the element type has a non-virtual destructor, Ptr has already
1879 /// been converted to the type of the parameter of 'operator delete'. Otherwise
1880 /// Ptr points to an object of the static type.
1881 static void EmitDestroyingObjectDelete(CodeGenFunction &CGF,
1882                                        const CXXDeleteExpr *DE, Address Ptr,
1883                                        QualType ElementType) {
1884   auto *Dtor = ElementType->getAsCXXRecordDecl()->getDestructor();
1885   if (Dtor && Dtor->isVirtual())
1886     CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
1887                                                 Dtor);
1888   else
1889     CGF.EmitDeleteCall(DE->getOperatorDelete(), Ptr.getPointer(), ElementType);
1890 }
1891 
1892 /// Emit the code for deleting a single object.
1893 /// \return \c true if we started emitting UnconditionalDeleteBlock, \c false
1894 /// if not.
1895 static bool EmitObjectDelete(CodeGenFunction &CGF,
1896                              const CXXDeleteExpr *DE,
1897                              Address Ptr,
1898                              QualType ElementType,
1899                              llvm::BasicBlock *UnconditionalDeleteBlock) {
1900   // C++11 [expr.delete]p3:
1901   //   If the static type of the object to be deleted is different from its
1902   //   dynamic type, the static type shall be a base class of the dynamic type
1903   //   of the object to be deleted and the static type shall have a virtual
1904   //   destructor or the behavior is undefined.
1905   CGF.EmitTypeCheck(CodeGenFunction::TCK_MemberCall,
1906                     DE->getExprLoc(), Ptr.getPointer(),
1907                     ElementType);
1908 
1909   const FunctionDecl *OperatorDelete = DE->getOperatorDelete();
1910   assert(!OperatorDelete->isDestroyingOperatorDelete());
1911 
1912   // Find the destructor for the type, if applicable.  If the
1913   // destructor is virtual, we'll just emit the vcall and return.
1914   const CXXDestructorDecl *Dtor = nullptr;
1915   if (const RecordType *RT = ElementType->getAs<RecordType>()) {
1916     CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1917     if (RD->hasDefinition() && !RD->hasTrivialDestructor()) {
1918       Dtor = RD->getDestructor();
1919 
1920       if (Dtor->isVirtual()) {
1921         bool UseVirtualCall = true;
1922         const Expr *Base = DE->getArgument();
1923         if (auto *DevirtualizedDtor =
1924                 dyn_cast_or_null<const CXXDestructorDecl>(
1925                     Dtor->getDevirtualizedMethod(
1926                         Base, CGF.CGM.getLangOpts().AppleKext))) {
1927           UseVirtualCall = false;
1928           const CXXRecordDecl *DevirtualizedClass =
1929               DevirtualizedDtor->getParent();
1930           if (declaresSameEntity(getCXXRecord(Base), DevirtualizedClass)) {
1931             // Devirtualized to the class of the base type (the type of the
1932             // whole expression).
1933             Dtor = DevirtualizedDtor;
1934           } else {
1935             // Devirtualized to some other type. Would need to cast the this
1936             // pointer to that type but we don't have support for that yet, so
1937             // do a virtual call. FIXME: handle the case where it is
1938             // devirtualized to the derived type (the type of the inner
1939             // expression) as in EmitCXXMemberOrOperatorMemberCallExpr.
1940             UseVirtualCall = true;
1941           }
1942         }
1943         if (UseVirtualCall) {
1944           CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
1945                                                       Dtor);
1946           return false;
1947         }
1948       }
1949     }
1950   }
1951 
1952   // Make sure that we call delete even if the dtor throws.
1953   // This doesn't have to a conditional cleanup because we're going
1954   // to pop it off in a second.
1955   CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
1956                                             Ptr.getPointer(),
1957                                             OperatorDelete, ElementType);
1958 
1959   if (Dtor)
1960     CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
1961                               /*ForVirtualBase=*/false,
1962                               /*Delegating=*/false,
1963                               Ptr, ElementType);
1964   else if (auto Lifetime = ElementType.getObjCLifetime()) {
1965     switch (Lifetime) {
1966     case Qualifiers::OCL_None:
1967     case Qualifiers::OCL_ExplicitNone:
1968     case Qualifiers::OCL_Autoreleasing:
1969       break;
1970 
1971     case Qualifiers::OCL_Strong:
1972       CGF.EmitARCDestroyStrong(Ptr, ARCPreciseLifetime);
1973       break;
1974 
1975     case Qualifiers::OCL_Weak:
1976       CGF.EmitARCDestroyWeak(Ptr);
1977       break;
1978     }
1979   }
1980 
1981   // When optimizing for size, call 'operator delete' unconditionally.
1982   if (CGF.CGM.getCodeGenOpts().OptimizeSize > 1) {
1983     CGF.EmitBlock(UnconditionalDeleteBlock);
1984     CGF.PopCleanupBlock();
1985     return true;
1986   }
1987 
1988   CGF.PopCleanupBlock();
1989   return false;
1990 }
1991 
1992 namespace {
1993   /// Calls the given 'operator delete' on an array of objects.
1994   struct CallArrayDelete final : EHScopeStack::Cleanup {
1995     llvm::Value *Ptr;
1996     const FunctionDecl *OperatorDelete;
1997     llvm::Value *NumElements;
1998     QualType ElementType;
1999     CharUnits CookieSize;
2000 
2001     CallArrayDelete(llvm::Value *Ptr,
2002                     const FunctionDecl *OperatorDelete,
2003                     llvm::Value *NumElements,
2004                     QualType ElementType,
2005                     CharUnits CookieSize)
2006       : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements),
2007         ElementType(ElementType), CookieSize(CookieSize) {}
2008 
2009     void Emit(CodeGenFunction &CGF, Flags flags) override {
2010       CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType, NumElements,
2011                          CookieSize);
2012     }
2013   };
2014 }
2015 
2016 /// Emit the code for deleting an array of objects.
2017 static void EmitArrayDelete(CodeGenFunction &CGF,
2018                             const CXXDeleteExpr *E,
2019                             Address deletedPtr,
2020                             QualType elementType) {
2021   llvm::Value *numElements = nullptr;
2022   llvm::Value *allocatedPtr = nullptr;
2023   CharUnits cookieSize;
2024   CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType,
2025                                       numElements, allocatedPtr, cookieSize);
2026 
2027   assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer");
2028 
2029   // Make sure that we call delete even if one of the dtors throws.
2030   const FunctionDecl *operatorDelete = E->getOperatorDelete();
2031   CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup,
2032                                            allocatedPtr, operatorDelete,
2033                                            numElements, elementType,
2034                                            cookieSize);
2035 
2036   // Destroy the elements.
2037   if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) {
2038     assert(numElements && "no element count for a type with a destructor!");
2039 
2040     CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
2041     CharUnits elementAlign =
2042       deletedPtr.getAlignment().alignmentOfArrayElement(elementSize);
2043 
2044     llvm::Value *arrayBegin = deletedPtr.getPointer();
2045     llvm::Value *arrayEnd = CGF.Builder.CreateInBoundsGEP(
2046       deletedPtr.getElementType(), arrayBegin, numElements, "delete.end");
2047 
2048     // Note that it is legal to allocate a zero-length array, and we
2049     // can never fold the check away because the length should always
2050     // come from a cookie.
2051     CGF.emitArrayDestroy(arrayBegin, arrayEnd, elementType, elementAlign,
2052                          CGF.getDestroyer(dtorKind),
2053                          /*checkZeroLength*/ true,
2054                          CGF.needsEHCleanup(dtorKind));
2055   }
2056 
2057   // Pop the cleanup block.
2058   CGF.PopCleanupBlock();
2059 }
2060 
2061 void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) {
2062   const Expr *Arg = E->getArgument();
2063   Address Ptr = EmitPointerWithAlignment(Arg);
2064 
2065   // Null check the pointer.
2066   //
2067   // We could avoid this null check if we can determine that the object
2068   // destruction is trivial and doesn't require an array cookie; we can
2069   // unconditionally perform the operator delete call in that case. For now, we
2070   // assume that deleted pointers are null rarely enough that it's better to
2071   // keep the branch. This might be worth revisiting for a -O0 code size win.
2072   llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull");
2073   llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end");
2074 
2075   llvm::Value *IsNull = Builder.CreateIsNull(Ptr.getPointer(), "isnull");
2076 
2077   Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull);
2078   EmitBlock(DeleteNotNull);
2079 
2080   QualType DeleteTy = E->getDestroyedType();
2081 
2082   // A destroying operator delete overrides the entire operation of the
2083   // delete expression.
2084   if (E->getOperatorDelete()->isDestroyingOperatorDelete()) {
2085     EmitDestroyingObjectDelete(*this, E, Ptr, DeleteTy);
2086     EmitBlock(DeleteEnd);
2087     return;
2088   }
2089 
2090   // We might be deleting a pointer to array.  If so, GEP down to the
2091   // first non-array element.
2092   // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*)
2093   if (DeleteTy->isConstantArrayType()) {
2094     llvm::Value *Zero = Builder.getInt32(0);
2095     SmallVector<llvm::Value*,8> GEP;
2096 
2097     GEP.push_back(Zero); // point at the outermost array
2098 
2099     // For each layer of array type we're pointing at:
2100     while (const ConstantArrayType *Arr
2101              = getContext().getAsConstantArrayType(DeleteTy)) {
2102       // 1. Unpeel the array type.
2103       DeleteTy = Arr->getElementType();
2104 
2105       // 2. GEP to the first element of the array.
2106       GEP.push_back(Zero);
2107     }
2108 
2109     Ptr = Address(Builder.CreateInBoundsGEP(Ptr.getElementType(),
2110                                             Ptr.getPointer(), GEP, "del.first"),
2111                   Ptr.getAlignment());
2112   }
2113 
2114   assert(ConvertTypeForMem(DeleteTy) == Ptr.getElementType());
2115 
2116   if (E->isArrayForm()) {
2117     EmitArrayDelete(*this, E, Ptr, DeleteTy);
2118     EmitBlock(DeleteEnd);
2119   } else {
2120     if (!EmitObjectDelete(*this, E, Ptr, DeleteTy, DeleteEnd))
2121       EmitBlock(DeleteEnd);
2122   }
2123 }
2124 
2125 static bool isGLValueFromPointerDeref(const Expr *E) {
2126   E = E->IgnoreParens();
2127 
2128   if (const auto *CE = dyn_cast<CastExpr>(E)) {
2129     if (!CE->getSubExpr()->isGLValue())
2130       return false;
2131     return isGLValueFromPointerDeref(CE->getSubExpr());
2132   }
2133 
2134   if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E))
2135     return isGLValueFromPointerDeref(OVE->getSourceExpr());
2136 
2137   if (const auto *BO = dyn_cast<BinaryOperator>(E))
2138     if (BO->getOpcode() == BO_Comma)
2139       return isGLValueFromPointerDeref(BO->getRHS());
2140 
2141   if (const auto *ACO = dyn_cast<AbstractConditionalOperator>(E))
2142     return isGLValueFromPointerDeref(ACO->getTrueExpr()) ||
2143            isGLValueFromPointerDeref(ACO->getFalseExpr());
2144 
2145   // C++11 [expr.sub]p1:
2146   //   The expression E1[E2] is identical (by definition) to *((E1)+(E2))
2147   if (isa<ArraySubscriptExpr>(E))
2148     return true;
2149 
2150   if (const auto *UO = dyn_cast<UnaryOperator>(E))
2151     if (UO->getOpcode() == UO_Deref)
2152       return true;
2153 
2154   return false;
2155 }
2156 
2157 static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, const Expr *E,
2158                                          llvm::Type *StdTypeInfoPtrTy) {
2159   // Get the vtable pointer.
2160   Address ThisPtr = CGF.EmitLValue(E).getAddress(CGF);
2161 
2162   QualType SrcRecordTy = E->getType();
2163 
2164   // C++ [class.cdtor]p4:
2165   //   If the operand of typeid refers to the object under construction or
2166   //   destruction and the static type of the operand is neither the constructor
2167   //   or destructor’s class nor one of its bases, the behavior is undefined.
2168   CGF.EmitTypeCheck(CodeGenFunction::TCK_DynamicOperation, E->getExprLoc(),
2169                     ThisPtr.getPointer(), SrcRecordTy);
2170 
2171   // C++ [expr.typeid]p2:
2172   //   If the glvalue expression is obtained by applying the unary * operator to
2173   //   a pointer and the pointer is a null pointer value, the typeid expression
2174   //   throws the std::bad_typeid exception.
2175   //
2176   // However, this paragraph's intent is not clear.  We choose a very generous
2177   // interpretation which implores us to consider comma operators, conditional
2178   // operators, parentheses and other such constructs.
2179   if (CGF.CGM.getCXXABI().shouldTypeidBeNullChecked(
2180           isGLValueFromPointerDeref(E), SrcRecordTy)) {
2181     llvm::BasicBlock *BadTypeidBlock =
2182         CGF.createBasicBlock("typeid.bad_typeid");
2183     llvm::BasicBlock *EndBlock = CGF.createBasicBlock("typeid.end");
2184 
2185     llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr.getPointer());
2186     CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock);
2187 
2188     CGF.EmitBlock(BadTypeidBlock);
2189     CGF.CGM.getCXXABI().EmitBadTypeidCall(CGF);
2190     CGF.EmitBlock(EndBlock);
2191   }
2192 
2193   return CGF.CGM.getCXXABI().EmitTypeid(CGF, SrcRecordTy, ThisPtr,
2194                                         StdTypeInfoPtrTy);
2195 }
2196 
2197 llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) {
2198   llvm::Type *StdTypeInfoPtrTy =
2199     ConvertType(E->getType())->getPointerTo();
2200 
2201   if (E->isTypeOperand()) {
2202     llvm::Constant *TypeInfo =
2203         CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand(getContext()));
2204     return Builder.CreateBitCast(TypeInfo, StdTypeInfoPtrTy);
2205   }
2206 
2207   // C++ [expr.typeid]p2:
2208   //   When typeid is applied to a glvalue expression whose type is a
2209   //   polymorphic class type, the result refers to a std::type_info object
2210   //   representing the type of the most derived object (that is, the dynamic
2211   //   type) to which the glvalue refers.
2212   // If the operand is already most derived object, no need to look up vtable.
2213   if (E->isPotentiallyEvaluated() && !E->isMostDerived(getContext()))
2214     return EmitTypeidFromVTable(*this, E->getExprOperand(),
2215                                 StdTypeInfoPtrTy);
2216 
2217   QualType OperandTy = E->getExprOperand()->getType();
2218   return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy),
2219                                StdTypeInfoPtrTy);
2220 }
2221 
2222 static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF,
2223                                           QualType DestTy) {
2224   llvm::Type *DestLTy = CGF.ConvertType(DestTy);
2225   if (DestTy->isPointerType())
2226     return llvm::Constant::getNullValue(DestLTy);
2227 
2228   /// C++ [expr.dynamic.cast]p9:
2229   ///   A failed cast to reference type throws std::bad_cast
2230   if (!CGF.CGM.getCXXABI().EmitBadCastCall(CGF))
2231     return nullptr;
2232 
2233   CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end"));
2234   return llvm::UndefValue::get(DestLTy);
2235 }
2236 
2237 llvm::Value *CodeGenFunction::EmitDynamicCast(Address ThisAddr,
2238                                               const CXXDynamicCastExpr *DCE) {
2239   CGM.EmitExplicitCastExprType(DCE, this);
2240   QualType DestTy = DCE->getTypeAsWritten();
2241 
2242   QualType SrcTy = DCE->getSubExpr()->getType();
2243 
2244   // C++ [expr.dynamic.cast]p7:
2245   //   If T is "pointer to cv void," then the result is a pointer to the most
2246   //   derived object pointed to by v.
2247   const PointerType *DestPTy = DestTy->getAs<PointerType>();
2248 
2249   bool isDynamicCastToVoid;
2250   QualType SrcRecordTy;
2251   QualType DestRecordTy;
2252   if (DestPTy) {
2253     isDynamicCastToVoid = DestPTy->getPointeeType()->isVoidType();
2254     SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType();
2255     DestRecordTy = DestPTy->getPointeeType();
2256   } else {
2257     isDynamicCastToVoid = false;
2258     SrcRecordTy = SrcTy;
2259     DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType();
2260   }
2261 
2262   // C++ [class.cdtor]p5:
2263   //   If the operand of the dynamic_cast refers to the object under
2264   //   construction or destruction and the static type of the operand is not a
2265   //   pointer to or object of the constructor or destructor’s own class or one
2266   //   of its bases, the dynamic_cast results in undefined behavior.
2267   EmitTypeCheck(TCK_DynamicOperation, DCE->getExprLoc(), ThisAddr.getPointer(),
2268                 SrcRecordTy);
2269 
2270   if (DCE->isAlwaysNull())
2271     if (llvm::Value *T = EmitDynamicCastToNull(*this, DestTy))
2272       return T;
2273 
2274   assert(SrcRecordTy->isRecordType() && "source type must be a record type!");
2275 
2276   // C++ [expr.dynamic.cast]p4:
2277   //   If the value of v is a null pointer value in the pointer case, the result
2278   //   is the null pointer value of type T.
2279   bool ShouldNullCheckSrcValue =
2280       CGM.getCXXABI().shouldDynamicCastCallBeNullChecked(SrcTy->isPointerType(),
2281                                                          SrcRecordTy);
2282 
2283   llvm::BasicBlock *CastNull = nullptr;
2284   llvm::BasicBlock *CastNotNull = nullptr;
2285   llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end");
2286 
2287   if (ShouldNullCheckSrcValue) {
2288     CastNull = createBasicBlock("dynamic_cast.null");
2289     CastNotNull = createBasicBlock("dynamic_cast.notnull");
2290 
2291     llvm::Value *IsNull = Builder.CreateIsNull(ThisAddr.getPointer());
2292     Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
2293     EmitBlock(CastNotNull);
2294   }
2295 
2296   llvm::Value *Value;
2297   if (isDynamicCastToVoid) {
2298     Value = CGM.getCXXABI().EmitDynamicCastToVoid(*this, ThisAddr, SrcRecordTy,
2299                                                   DestTy);
2300   } else {
2301     assert(DestRecordTy->isRecordType() &&
2302            "destination type must be a record type!");
2303     Value = CGM.getCXXABI().EmitDynamicCastCall(*this, ThisAddr, SrcRecordTy,
2304                                                 DestTy, DestRecordTy, CastEnd);
2305     CastNotNull = Builder.GetInsertBlock();
2306   }
2307 
2308   if (ShouldNullCheckSrcValue) {
2309     EmitBranch(CastEnd);
2310 
2311     EmitBlock(CastNull);
2312     EmitBranch(CastEnd);
2313   }
2314 
2315   EmitBlock(CastEnd);
2316 
2317   if (ShouldNullCheckSrcValue) {
2318     llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
2319     PHI->addIncoming(Value, CastNotNull);
2320     PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull);
2321 
2322     Value = PHI;
2323   }
2324 
2325   return Value;
2326 }
2327