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      1 //===--- CGExprCXX.cpp - Emit LLVM Code for C++ expressions ---------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This contains code dealing with code generation of C++ expressions
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "CodeGenFunction.h"
     15 #include "CGCUDARuntime.h"
     16 #include "CGCXXABI.h"
     17 #include "CGDebugInfo.h"
     18 #include "CGObjCRuntime.h"
     19 #include "clang/CodeGen/CGFunctionInfo.h"
     20 #include "clang/Frontend/CodeGenOptions.h"
     21 #include "llvm/IR/CallSite.h"
     22 #include "llvm/IR/Intrinsics.h"
     23 
     24 using namespace clang;
     25 using namespace CodeGen;
     26 
     27 RValue CodeGenFunction::EmitCXXMemberCall(const CXXMethodDecl *MD,
     28                                           SourceLocation CallLoc,
     29                                           llvm::Value *Callee,
     30                                           ReturnValueSlot ReturnValue,
     31                                           llvm::Value *This,
     32                                           llvm::Value *ImplicitParam,
     33                                           QualType ImplicitParamTy,
     34                                           CallExpr::const_arg_iterator ArgBeg,
     35                                           CallExpr::const_arg_iterator ArgEnd) {
     36   assert(MD->isInstance() &&
     37          "Trying to emit a member call expr on a static method!");
     38 
     39   // C++11 [class.mfct.non-static]p2:
     40   //   If a non-static member function of a class X is called for an object that
     41   //   is not of type X, or of a type derived from X, the behavior is undefined.
     42   EmitTypeCheck(isa<CXXConstructorDecl>(MD) ? TCK_ConstructorCall
     43                                             : TCK_MemberCall,
     44                 CallLoc, This, getContext().getRecordType(MD->getParent()));
     45 
     46   CallArgList Args;
     47 
     48   // Push the this ptr.
     49   Args.add(RValue::get(This), MD->getThisType(getContext()));
     50 
     51   // If there is an implicit parameter (e.g. VTT), emit it.
     52   if (ImplicitParam) {
     53     Args.add(RValue::get(ImplicitParam), ImplicitParamTy);
     54   }
     55 
     56   const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
     57   RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size());
     58 
     59   // And the rest of the call args.
     60   EmitCallArgs(Args, FPT, ArgBeg, ArgEnd);
     61 
     62   return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required),
     63                   Callee, ReturnValue, Args, MD);
     64 }
     65 
     66 static CXXRecordDecl *getCXXRecord(const Expr *E) {
     67   QualType T = E->getType();
     68   if (const PointerType *PTy = T->getAs<PointerType>())
     69     T = PTy->getPointeeType();
     70   const RecordType *Ty = T->castAs<RecordType>();
     71   return cast<CXXRecordDecl>(Ty->getDecl());
     72 }
     73 
     74 // Note: This function also emit constructor calls to support a MSVC
     75 // extensions allowing explicit constructor function call.
     76 RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE,
     77                                               ReturnValueSlot ReturnValue) {
     78   const Expr *callee = CE->getCallee()->IgnoreParens();
     79 
     80   if (isa<BinaryOperator>(callee))
     81     return EmitCXXMemberPointerCallExpr(CE, ReturnValue);
     82 
     83   const MemberExpr *ME = cast<MemberExpr>(callee);
     84   const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl());
     85 
     86   if (MD->isStatic()) {
     87     // The method is static, emit it as we would a regular call.
     88     llvm::Value *Callee = CGM.GetAddrOfFunction(MD);
     89     return EmitCall(getContext().getPointerType(MD->getType()), Callee,
     90                     CE->getLocStart(), ReturnValue, CE->arg_begin(),
     91                     CE->arg_end());
     92   }
     93 
     94   // Compute the object pointer.
     95   const Expr *Base = ME->getBase();
     96   bool CanUseVirtualCall = MD->isVirtual() && !ME->hasQualifier();
     97 
     98   const CXXMethodDecl *DevirtualizedMethod = nullptr;
     99   if (CanUseVirtualCall && CanDevirtualizeMemberFunctionCall(Base, MD)) {
    100     const CXXRecordDecl *BestDynamicDecl = Base->getBestDynamicClassType();
    101     DevirtualizedMethod = MD->getCorrespondingMethodInClass(BestDynamicDecl);
    102     assert(DevirtualizedMethod);
    103     const CXXRecordDecl *DevirtualizedClass = DevirtualizedMethod->getParent();
    104     const Expr *Inner = Base->ignoreParenBaseCasts();
    105     if (getCXXRecord(Inner) == DevirtualizedClass)
    106       // If the class of the Inner expression is where the dynamic method
    107       // is defined, build the this pointer from it.
    108       Base = Inner;
    109     else if (getCXXRecord(Base) != DevirtualizedClass) {
    110       // If the method is defined in a class that is not the best dynamic
    111       // one or the one of the full expression, we would have to build
    112       // a derived-to-base cast to compute the correct this pointer, but
    113       // we don't have support for that yet, so do a virtual call.
    114       DevirtualizedMethod = nullptr;
    115     }
    116     // If the return types are not the same, this might be a case where more
    117     // code needs to run to compensate for it. For example, the derived
    118     // method might return a type that inherits form from the return
    119     // type of MD and has a prefix.
    120     // For now we just avoid devirtualizing these covariant cases.
    121     if (DevirtualizedMethod &&
    122         DevirtualizedMethod->getReturnType().getCanonicalType() !=
    123             MD->getReturnType().getCanonicalType())
    124       DevirtualizedMethod = nullptr;
    125   }
    126 
    127   llvm::Value *This;
    128   if (ME->isArrow())
    129     This = EmitScalarExpr(Base);
    130   else
    131     This = EmitLValue(Base).getAddress();
    132 
    133 
    134   if (MD->isTrivial()) {
    135     if (isa<CXXDestructorDecl>(MD)) return RValue::get(nullptr);
    136     if (isa<CXXConstructorDecl>(MD) &&
    137         cast<CXXConstructorDecl>(MD)->isDefaultConstructor())
    138       return RValue::get(nullptr);
    139 
    140     if (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) {
    141       // We don't like to generate the trivial copy/move assignment operator
    142       // when it isn't necessary; just produce the proper effect here.
    143       llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress();
    144       EmitAggregateAssign(This, RHS, CE->getType());
    145       return RValue::get(This);
    146     }
    147 
    148     if (isa<CXXConstructorDecl>(MD) &&
    149         cast<CXXConstructorDecl>(MD)->isCopyOrMoveConstructor()) {
    150       // Trivial move and copy ctor are the same.
    151       llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress();
    152       EmitSynthesizedCXXCopyCtorCall(cast<CXXConstructorDecl>(MD), This, RHS,
    153                                      CE->arg_begin(), CE->arg_end());
    154       return RValue::get(This);
    155     }
    156     llvm_unreachable("unknown trivial member function");
    157   }
    158 
    159   // Compute the function type we're calling.
    160   const CXXMethodDecl *CalleeDecl = DevirtualizedMethod ? DevirtualizedMethod : MD;
    161   const CGFunctionInfo *FInfo = nullptr;
    162   if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl))
    163     FInfo = &CGM.getTypes().arrangeCXXDestructor(Dtor,
    164                                                  Dtor_Complete);
    165   else if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(CalleeDecl))
    166     FInfo = &CGM.getTypes().arrangeCXXConstructorDeclaration(Ctor,
    167                                                              Ctor_Complete);
    168   else
    169     FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(CalleeDecl);
    170 
    171   llvm::FunctionType *Ty = CGM.getTypes().GetFunctionType(*FInfo);
    172 
    173   // C++ [class.virtual]p12:
    174   //   Explicit qualification with the scope operator (5.1) suppresses the
    175   //   virtual call mechanism.
    176   //
    177   // We also don't emit a virtual call if the base expression has a record type
    178   // because then we know what the type is.
    179   bool UseVirtualCall = CanUseVirtualCall && !DevirtualizedMethod;
    180   llvm::Value *Callee;
    181 
    182   if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(MD)) {
    183     assert(CE->arg_begin() == CE->arg_end() &&
    184            "Destructor shouldn't have explicit parameters");
    185     assert(ReturnValue.isNull() && "Destructor shouldn't have return value");
    186     if (UseVirtualCall) {
    187       CGM.getCXXABI().EmitVirtualDestructorCall(*this, Dtor, Dtor_Complete,
    188                                                 CE->getExprLoc(), This);
    189     } else {
    190       if (getLangOpts().AppleKext &&
    191           MD->isVirtual() &&
    192           ME->hasQualifier())
    193         Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty);
    194       else if (!DevirtualizedMethod)
    195         Callee = CGM.GetAddrOfCXXDestructor(Dtor, Dtor_Complete, FInfo, Ty);
    196       else {
    197         const CXXDestructorDecl *DDtor =
    198           cast<CXXDestructorDecl>(DevirtualizedMethod);
    199         Callee = CGM.GetAddrOfFunction(GlobalDecl(DDtor, Dtor_Complete), Ty);
    200       }
    201       EmitCXXMemberCall(MD, CE->getExprLoc(), Callee, ReturnValue, This,
    202                         /*ImplicitParam=*/nullptr, QualType(), nullptr,nullptr);
    203     }
    204     return RValue::get(nullptr);
    205   }
    206 
    207   if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
    208     Callee = CGM.GetAddrOfFunction(GlobalDecl(Ctor, Ctor_Complete), Ty);
    209   } else if (UseVirtualCall) {
    210     Callee = CGM.getCXXABI().getVirtualFunctionPointer(*this, MD, This, Ty);
    211   } else {
    212     if (getLangOpts().AppleKext &&
    213         MD->isVirtual() &&
    214         ME->hasQualifier())
    215       Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty);
    216     else if (!DevirtualizedMethod)
    217       Callee = CGM.GetAddrOfFunction(MD, Ty);
    218     else {
    219       Callee = CGM.GetAddrOfFunction(DevirtualizedMethod, Ty);
    220     }
    221   }
    222 
    223   if (MD->isVirtual()) {
    224     This = CGM.getCXXABI().adjustThisArgumentForVirtualFunctionCall(
    225         *this, MD, This, UseVirtualCall);
    226   }
    227 
    228   return EmitCXXMemberCall(MD, CE->getExprLoc(), Callee, ReturnValue, This,
    229                            /*ImplicitParam=*/nullptr, QualType(),
    230                            CE->arg_begin(), CE->arg_end());
    231 }
    232 
    233 RValue
    234 CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E,
    235                                               ReturnValueSlot ReturnValue) {
    236   const BinaryOperator *BO =
    237       cast<BinaryOperator>(E->getCallee()->IgnoreParens());
    238   const Expr *BaseExpr = BO->getLHS();
    239   const Expr *MemFnExpr = BO->getRHS();
    240 
    241   const MemberPointerType *MPT =
    242     MemFnExpr->getType()->castAs<MemberPointerType>();
    243 
    244   const FunctionProtoType *FPT =
    245     MPT->getPointeeType()->castAs<FunctionProtoType>();
    246   const CXXRecordDecl *RD =
    247     cast<CXXRecordDecl>(MPT->getClass()->getAs<RecordType>()->getDecl());
    248 
    249   // Get the member function pointer.
    250   llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr);
    251 
    252   // Emit the 'this' pointer.
    253   llvm::Value *This;
    254 
    255   if (BO->getOpcode() == BO_PtrMemI)
    256     This = EmitScalarExpr(BaseExpr);
    257   else
    258     This = EmitLValue(BaseExpr).getAddress();
    259 
    260   EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This,
    261                 QualType(MPT->getClass(), 0));
    262 
    263   // Ask the ABI to load the callee.  Note that This is modified.
    264   llvm::Value *Callee =
    265     CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This, MemFnPtr, MPT);
    266 
    267   CallArgList Args;
    268 
    269   QualType ThisType =
    270     getContext().getPointerType(getContext().getTagDeclType(RD));
    271 
    272   // Push the this ptr.
    273   Args.add(RValue::get(This), ThisType);
    274 
    275   RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, 1);
    276 
    277   // And the rest of the call args
    278   EmitCallArgs(Args, FPT, E->arg_begin(), E->arg_end());
    279   return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required),
    280                   Callee, ReturnValue, Args);
    281 }
    282 
    283 RValue
    284 CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
    285                                                const CXXMethodDecl *MD,
    286                                                ReturnValueSlot ReturnValue) {
    287   assert(MD->isInstance() &&
    288          "Trying to emit a member call expr on a static method!");
    289   LValue LV = EmitLValue(E->getArg(0));
    290   llvm::Value *This = LV.getAddress();
    291 
    292   if ((MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) &&
    293       MD->isTrivial()) {
    294     llvm::Value *Src = EmitLValue(E->getArg(1)).getAddress();
    295     QualType Ty = E->getType();
    296     EmitAggregateAssign(This, Src, Ty);
    297     return RValue::get(This);
    298   }
    299 
    300   llvm::Value *Callee = EmitCXXOperatorMemberCallee(E, MD, This);
    301   return EmitCXXMemberCall(MD, E->getExprLoc(), Callee, ReturnValue, This,
    302                            /*ImplicitParam=*/nullptr, QualType(),
    303                            E->arg_begin() + 1, E->arg_end());
    304 }
    305 
    306 RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E,
    307                                                ReturnValueSlot ReturnValue) {
    308   return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue);
    309 }
    310 
    311 static void EmitNullBaseClassInitialization(CodeGenFunction &CGF,
    312                                             llvm::Value *DestPtr,
    313                                             const CXXRecordDecl *Base) {
    314   if (Base->isEmpty())
    315     return;
    316 
    317   DestPtr = CGF.EmitCastToVoidPtr(DestPtr);
    318 
    319   const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base);
    320   CharUnits Size = Layout.getNonVirtualSize();
    321   CharUnits Align = Layout.getNonVirtualAlignment();
    322 
    323   llvm::Value *SizeVal = CGF.CGM.getSize(Size);
    324 
    325   // If the type contains a pointer to data member we can't memset it to zero.
    326   // Instead, create a null constant and copy it to the destination.
    327   // TODO: there are other patterns besides zero that we can usefully memset,
    328   // like -1, which happens to be the pattern used by member-pointers.
    329   // TODO: isZeroInitializable can be over-conservative in the case where a
    330   // virtual base contains a member pointer.
    331   if (!CGF.CGM.getTypes().isZeroInitializable(Base)) {
    332     llvm::Constant *NullConstant = CGF.CGM.EmitNullConstantForBase(Base);
    333 
    334     llvm::GlobalVariable *NullVariable =
    335       new llvm::GlobalVariable(CGF.CGM.getModule(), NullConstant->getType(),
    336                                /*isConstant=*/true,
    337                                llvm::GlobalVariable::PrivateLinkage,
    338                                NullConstant, Twine());
    339     NullVariable->setAlignment(Align.getQuantity());
    340     llvm::Value *SrcPtr = CGF.EmitCastToVoidPtr(NullVariable);
    341 
    342     // Get and call the appropriate llvm.memcpy overload.
    343     CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity());
    344     return;
    345   }
    346 
    347   // Otherwise, just memset the whole thing to zero.  This is legal
    348   // because in LLVM, all default initializers (other than the ones we just
    349   // handled above) are guaranteed to have a bit pattern of all zeros.
    350   CGF.Builder.CreateMemSet(DestPtr, CGF.Builder.getInt8(0), SizeVal,
    351                            Align.getQuantity());
    352 }
    353 
    354 void
    355 CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E,
    356                                       AggValueSlot Dest) {
    357   assert(!Dest.isIgnored() && "Must have a destination!");
    358   const CXXConstructorDecl *CD = E->getConstructor();
    359 
    360   // If we require zero initialization before (or instead of) calling the
    361   // constructor, as can be the case with a non-user-provided default
    362   // constructor, emit the zero initialization now, unless destination is
    363   // already zeroed.
    364   if (E->requiresZeroInitialization() && !Dest.isZeroed()) {
    365     switch (E->getConstructionKind()) {
    366     case CXXConstructExpr::CK_Delegating:
    367     case CXXConstructExpr::CK_Complete:
    368       EmitNullInitialization(Dest.getAddr(), E->getType());
    369       break;
    370     case CXXConstructExpr::CK_VirtualBase:
    371     case CXXConstructExpr::CK_NonVirtualBase:
    372       EmitNullBaseClassInitialization(*this, Dest.getAddr(), CD->getParent());
    373       break;
    374     }
    375   }
    376 
    377   // If this is a call to a trivial default constructor, do nothing.
    378   if (CD->isTrivial() && CD->isDefaultConstructor())
    379     return;
    380 
    381   // Elide the constructor if we're constructing from a temporary.
    382   // The temporary check is required because Sema sets this on NRVO
    383   // returns.
    384   if (getLangOpts().ElideConstructors && E->isElidable()) {
    385     assert(getContext().hasSameUnqualifiedType(E->getType(),
    386                                                E->getArg(0)->getType()));
    387     if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) {
    388       EmitAggExpr(E->getArg(0), Dest);
    389       return;
    390     }
    391   }
    392 
    393   if (const ConstantArrayType *arrayType
    394         = getContext().getAsConstantArrayType(E->getType())) {
    395     EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddr(),
    396                                E->arg_begin(), E->arg_end());
    397   } else {
    398     CXXCtorType Type = Ctor_Complete;
    399     bool ForVirtualBase = false;
    400     bool Delegating = false;
    401 
    402     switch (E->getConstructionKind()) {
    403      case CXXConstructExpr::CK_Delegating:
    404       // We should be emitting a constructor; GlobalDecl will assert this
    405       Type = CurGD.getCtorType();
    406       Delegating = true;
    407       break;
    408 
    409      case CXXConstructExpr::CK_Complete:
    410       Type = Ctor_Complete;
    411       break;
    412 
    413      case CXXConstructExpr::CK_VirtualBase:
    414       ForVirtualBase = true;
    415       // fall-through
    416 
    417      case CXXConstructExpr::CK_NonVirtualBase:
    418       Type = Ctor_Base;
    419     }
    420 
    421     // Call the constructor.
    422     EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating, Dest.getAddr(),
    423                            E->arg_begin(), E->arg_end());
    424   }
    425 }
    426 
    427 void
    428 CodeGenFunction::EmitSynthesizedCXXCopyCtor(llvm::Value *Dest,
    429                                             llvm::Value *Src,
    430                                             const Expr *Exp) {
    431   if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp))
    432     Exp = E->getSubExpr();
    433   assert(isa<CXXConstructExpr>(Exp) &&
    434          "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr");
    435   const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp);
    436   const CXXConstructorDecl *CD = E->getConstructor();
    437   RunCleanupsScope Scope(*this);
    438 
    439   // If we require zero initialization before (or instead of) calling the
    440   // constructor, as can be the case with a non-user-provided default
    441   // constructor, emit the zero initialization now.
    442   // FIXME. Do I still need this for a copy ctor synthesis?
    443   if (E->requiresZeroInitialization())
    444     EmitNullInitialization(Dest, E->getType());
    445 
    446   assert(!getContext().getAsConstantArrayType(E->getType())
    447          && "EmitSynthesizedCXXCopyCtor - Copied-in Array");
    448   EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, E->arg_begin(), E->arg_end());
    449 }
    450 
    451 static CharUnits CalculateCookiePadding(CodeGenFunction &CGF,
    452                                         const CXXNewExpr *E) {
    453   if (!E->isArray())
    454     return CharUnits::Zero();
    455 
    456   // No cookie is required if the operator new[] being used is the
    457   // reserved placement operator new[].
    458   if (E->getOperatorNew()->isReservedGlobalPlacementOperator())
    459     return CharUnits::Zero();
    460 
    461   return CGF.CGM.getCXXABI().GetArrayCookieSize(E);
    462 }
    463 
    464 static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF,
    465                                         const CXXNewExpr *e,
    466                                         unsigned minElements,
    467                                         llvm::Value *&numElements,
    468                                         llvm::Value *&sizeWithoutCookie) {
    469   QualType type = e->getAllocatedType();
    470 
    471   if (!e->isArray()) {
    472     CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
    473     sizeWithoutCookie
    474       = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity());
    475     return sizeWithoutCookie;
    476   }
    477 
    478   // The width of size_t.
    479   unsigned sizeWidth = CGF.SizeTy->getBitWidth();
    480 
    481   // Figure out the cookie size.
    482   llvm::APInt cookieSize(sizeWidth,
    483                          CalculateCookiePadding(CGF, e).getQuantity());
    484 
    485   // Emit the array size expression.
    486   // We multiply the size of all dimensions for NumElements.
    487   // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6.
    488   numElements = CGF.EmitScalarExpr(e->getArraySize());
    489   assert(isa<llvm::IntegerType>(numElements->getType()));
    490 
    491   // The number of elements can be have an arbitrary integer type;
    492   // essentially, we need to multiply it by a constant factor, add a
    493   // cookie size, and verify that the result is representable as a
    494   // size_t.  That's just a gloss, though, and it's wrong in one
    495   // important way: if the count is negative, it's an error even if
    496   // the cookie size would bring the total size >= 0.
    497   bool isSigned
    498     = e->getArraySize()->getType()->isSignedIntegerOrEnumerationType();
    499   llvm::IntegerType *numElementsType
    500     = cast<llvm::IntegerType>(numElements->getType());
    501   unsigned numElementsWidth = numElementsType->getBitWidth();
    502 
    503   // Compute the constant factor.
    504   llvm::APInt arraySizeMultiplier(sizeWidth, 1);
    505   while (const ConstantArrayType *CAT
    506              = CGF.getContext().getAsConstantArrayType(type)) {
    507     type = CAT->getElementType();
    508     arraySizeMultiplier *= CAT->getSize();
    509   }
    510 
    511   CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
    512   llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity());
    513   typeSizeMultiplier *= arraySizeMultiplier;
    514 
    515   // This will be a size_t.
    516   llvm::Value *size;
    517 
    518   // If someone is doing 'new int[42]' there is no need to do a dynamic check.
    519   // Don't bloat the -O0 code.
    520   if (llvm::ConstantInt *numElementsC =
    521         dyn_cast<llvm::ConstantInt>(numElements)) {
    522     const llvm::APInt &count = numElementsC->getValue();
    523 
    524     bool hasAnyOverflow = false;
    525 
    526     // If 'count' was a negative number, it's an overflow.
    527     if (isSigned && count.isNegative())
    528       hasAnyOverflow = true;
    529 
    530     // We want to do all this arithmetic in size_t.  If numElements is
    531     // wider than that, check whether it's already too big, and if so,
    532     // overflow.
    533     else if (numElementsWidth > sizeWidth &&
    534              numElementsWidth - sizeWidth > count.countLeadingZeros())
    535       hasAnyOverflow = true;
    536 
    537     // Okay, compute a count at the right width.
    538     llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth);
    539 
    540     // If there is a brace-initializer, we cannot allocate fewer elements than
    541     // there are initializers. If we do, that's treated like an overflow.
    542     if (adjustedCount.ult(minElements))
    543       hasAnyOverflow = true;
    544 
    545     // Scale numElements by that.  This might overflow, but we don't
    546     // care because it only overflows if allocationSize does, too, and
    547     // if that overflows then we shouldn't use this.
    548     numElements = llvm::ConstantInt::get(CGF.SizeTy,
    549                                          adjustedCount * arraySizeMultiplier);
    550 
    551     // Compute the size before cookie, and track whether it overflowed.
    552     bool overflow;
    553     llvm::APInt allocationSize
    554       = adjustedCount.umul_ov(typeSizeMultiplier, overflow);
    555     hasAnyOverflow |= overflow;
    556 
    557     // Add in the cookie, and check whether it's overflowed.
    558     if (cookieSize != 0) {
    559       // Save the current size without a cookie.  This shouldn't be
    560       // used if there was overflow.
    561       sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
    562 
    563       allocationSize = allocationSize.uadd_ov(cookieSize, overflow);
    564       hasAnyOverflow |= overflow;
    565     }
    566 
    567     // On overflow, produce a -1 so operator new will fail.
    568     if (hasAnyOverflow) {
    569       size = llvm::Constant::getAllOnesValue(CGF.SizeTy);
    570     } else {
    571       size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
    572     }
    573 
    574   // Otherwise, we might need to use the overflow intrinsics.
    575   } else {
    576     // There are up to five conditions we need to test for:
    577     // 1) if isSigned, we need to check whether numElements is negative;
    578     // 2) if numElementsWidth > sizeWidth, we need to check whether
    579     //   numElements is larger than something representable in size_t;
    580     // 3) if minElements > 0, we need to check whether numElements is smaller
    581     //    than that.
    582     // 4) we need to compute
    583     //      sizeWithoutCookie := numElements * typeSizeMultiplier
    584     //    and check whether it overflows; and
    585     // 5) if we need a cookie, we need to compute
    586     //      size := sizeWithoutCookie + cookieSize
    587     //    and check whether it overflows.
    588 
    589     llvm::Value *hasOverflow = nullptr;
    590 
    591     // If numElementsWidth > sizeWidth, then one way or another, we're
    592     // going to have to do a comparison for (2), and this happens to
    593     // take care of (1), too.
    594     if (numElementsWidth > sizeWidth) {
    595       llvm::APInt threshold(numElementsWidth, 1);
    596       threshold <<= sizeWidth;
    597 
    598       llvm::Value *thresholdV
    599         = llvm::ConstantInt::get(numElementsType, threshold);
    600 
    601       hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV);
    602       numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy);
    603 
    604     // Otherwise, if we're signed, we want to sext up to size_t.
    605     } else if (isSigned) {
    606       if (numElementsWidth < sizeWidth)
    607         numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy);
    608 
    609       // If there's a non-1 type size multiplier, then we can do the
    610       // signedness check at the same time as we do the multiply
    611       // because a negative number times anything will cause an
    612       // unsigned overflow.  Otherwise, we have to do it here. But at least
    613       // in this case, we can subsume the >= minElements check.
    614       if (typeSizeMultiplier == 1)
    615         hasOverflow = CGF.Builder.CreateICmpSLT(numElements,
    616                               llvm::ConstantInt::get(CGF.SizeTy, minElements));
    617 
    618     // Otherwise, zext up to size_t if necessary.
    619     } else if (numElementsWidth < sizeWidth) {
    620       numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy);
    621     }
    622 
    623     assert(numElements->getType() == CGF.SizeTy);
    624 
    625     if (minElements) {
    626       // Don't allow allocation of fewer elements than we have initializers.
    627       if (!hasOverflow) {
    628         hasOverflow = CGF.Builder.CreateICmpULT(numElements,
    629                               llvm::ConstantInt::get(CGF.SizeTy, minElements));
    630       } else if (numElementsWidth > sizeWidth) {
    631         // The other existing overflow subsumes this check.
    632         // We do an unsigned comparison, since any signed value < -1 is
    633         // taken care of either above or below.
    634         hasOverflow = CGF.Builder.CreateOr(hasOverflow,
    635                           CGF.Builder.CreateICmpULT(numElements,
    636                               llvm::ConstantInt::get(CGF.SizeTy, minElements)));
    637       }
    638     }
    639 
    640     size = numElements;
    641 
    642     // Multiply by the type size if necessary.  This multiplier
    643     // includes all the factors for nested arrays.
    644     //
    645     // This step also causes numElements to be scaled up by the
    646     // nested-array factor if necessary.  Overflow on this computation
    647     // can be ignored because the result shouldn't be used if
    648     // allocation fails.
    649     if (typeSizeMultiplier != 1) {
    650       llvm::Value *umul_with_overflow
    651         = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy);
    652 
    653       llvm::Value *tsmV =
    654         llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier);
    655       llvm::Value *result =
    656         CGF.Builder.CreateCall2(umul_with_overflow, size, tsmV);
    657 
    658       llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
    659       if (hasOverflow)
    660         hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
    661       else
    662         hasOverflow = overflowed;
    663 
    664       size = CGF.Builder.CreateExtractValue(result, 0);
    665 
    666       // Also scale up numElements by the array size multiplier.
    667       if (arraySizeMultiplier != 1) {
    668         // If the base element type size is 1, then we can re-use the
    669         // multiply we just did.
    670         if (typeSize.isOne()) {
    671           assert(arraySizeMultiplier == typeSizeMultiplier);
    672           numElements = size;
    673 
    674         // Otherwise we need a separate multiply.
    675         } else {
    676           llvm::Value *asmV =
    677             llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier);
    678           numElements = CGF.Builder.CreateMul(numElements, asmV);
    679         }
    680       }
    681     } else {
    682       // numElements doesn't need to be scaled.
    683       assert(arraySizeMultiplier == 1);
    684     }
    685 
    686     // Add in the cookie size if necessary.
    687     if (cookieSize != 0) {
    688       sizeWithoutCookie = size;
    689 
    690       llvm::Value *uadd_with_overflow
    691         = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy);
    692 
    693       llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize);
    694       llvm::Value *result =
    695         CGF.Builder.CreateCall2(uadd_with_overflow, size, cookieSizeV);
    696 
    697       llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
    698       if (hasOverflow)
    699         hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
    700       else
    701         hasOverflow = overflowed;
    702 
    703       size = CGF.Builder.CreateExtractValue(result, 0);
    704     }
    705 
    706     // If we had any possibility of dynamic overflow, make a select to
    707     // overwrite 'size' with an all-ones value, which should cause
    708     // operator new to throw.
    709     if (hasOverflow)
    710       size = CGF.Builder.CreateSelect(hasOverflow,
    711                                  llvm::Constant::getAllOnesValue(CGF.SizeTy),
    712                                       size);
    713   }
    714 
    715   if (cookieSize == 0)
    716     sizeWithoutCookie = size;
    717   else
    718     assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?");
    719 
    720   return size;
    721 }
    722 
    723 static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init,
    724                                     QualType AllocType, llvm::Value *NewPtr) {
    725   // FIXME: Refactor with EmitExprAsInit.
    726   CharUnits Alignment = CGF.getContext().getTypeAlignInChars(AllocType);
    727   switch (CGF.getEvaluationKind(AllocType)) {
    728   case TEK_Scalar:
    729     CGF.EmitScalarInit(Init, nullptr, CGF.MakeAddrLValue(NewPtr, AllocType,
    730                                                          Alignment),
    731                        false);
    732     return;
    733   case TEK_Complex:
    734     CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType,
    735                                                            Alignment),
    736                                   /*isInit*/ true);
    737     return;
    738   case TEK_Aggregate: {
    739     AggValueSlot Slot
    740       = AggValueSlot::forAddr(NewPtr, Alignment, AllocType.getQualifiers(),
    741                               AggValueSlot::IsDestructed,
    742                               AggValueSlot::DoesNotNeedGCBarriers,
    743                               AggValueSlot::IsNotAliased);
    744     CGF.EmitAggExpr(Init, Slot);
    745     return;
    746   }
    747   }
    748   llvm_unreachable("bad evaluation kind");
    749 }
    750 
    751 void
    752 CodeGenFunction::EmitNewArrayInitializer(const CXXNewExpr *E,
    753                                          QualType ElementType,
    754                                          llvm::Value *BeginPtr,
    755                                          llvm::Value *NumElements,
    756                                          llvm::Value *AllocSizeWithoutCookie) {
    757   // If we have a type with trivial initialization and no initializer,
    758   // there's nothing to do.
    759   if (!E->hasInitializer())
    760     return;
    761 
    762   llvm::Value *CurPtr = BeginPtr;
    763 
    764   unsigned InitListElements = 0;
    765 
    766   const Expr *Init = E->getInitializer();
    767   llvm::AllocaInst *EndOfInit = nullptr;
    768   QualType::DestructionKind DtorKind = ElementType.isDestructedType();
    769   EHScopeStack::stable_iterator Cleanup;
    770   llvm::Instruction *CleanupDominator = nullptr;
    771 
    772   // If the initializer is an initializer list, first do the explicit elements.
    773   if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
    774     InitListElements = ILE->getNumInits();
    775 
    776     // If this is a multi-dimensional array new, we will initialize multiple
    777     // elements with each init list element.
    778     QualType AllocType = E->getAllocatedType();
    779     if (const ConstantArrayType *CAT = dyn_cast_or_null<ConstantArrayType>(
    780             AllocType->getAsArrayTypeUnsafe())) {
    781       unsigned AS = CurPtr->getType()->getPointerAddressSpace();
    782       llvm::Type *AllocPtrTy = ConvertTypeForMem(AllocType)->getPointerTo(AS);
    783       CurPtr = Builder.CreateBitCast(CurPtr, AllocPtrTy);
    784       InitListElements *= getContext().getConstantArrayElementCount(CAT);
    785     }
    786 
    787     // Enter a partial-destruction Cleanup if necessary.
    788     if (needsEHCleanup(DtorKind)) {
    789       // In principle we could tell the Cleanup where we are more
    790       // directly, but the control flow can get so varied here that it
    791       // would actually be quite complex.  Therefore we go through an
    792       // alloca.
    793       EndOfInit = CreateTempAlloca(BeginPtr->getType(), "array.init.end");
    794       CleanupDominator = Builder.CreateStore(BeginPtr, EndOfInit);
    795       pushIrregularPartialArrayCleanup(BeginPtr, EndOfInit, ElementType,
    796                                        getDestroyer(DtorKind));
    797       Cleanup = EHStack.stable_begin();
    798     }
    799 
    800     for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) {
    801       // Tell the cleanup that it needs to destroy up to this
    802       // element.  TODO: some of these stores can be trivially
    803       // observed to be unnecessary.
    804       if (EndOfInit)
    805         Builder.CreateStore(Builder.CreateBitCast(CurPtr, BeginPtr->getType()),
    806                             EndOfInit);
    807       // FIXME: If the last initializer is an incomplete initializer list for
    808       // an array, and we have an array filler, we can fold together the two
    809       // initialization loops.
    810       StoreAnyExprIntoOneUnit(*this, ILE->getInit(i),
    811                               ILE->getInit(i)->getType(), CurPtr);
    812       CurPtr = Builder.CreateConstInBoundsGEP1_32(CurPtr, 1, "array.exp.next");
    813     }
    814 
    815     // The remaining elements are filled with the array filler expression.
    816     Init = ILE->getArrayFiller();
    817 
    818     // Extract the initializer for the individual array elements by pulling
    819     // out the array filler from all the nested initializer lists. This avoids
    820     // generating a nested loop for the initialization.
    821     while (Init && Init->getType()->isConstantArrayType()) {
    822       auto *SubILE = dyn_cast<InitListExpr>(Init);
    823       if (!SubILE)
    824         break;
    825       assert(SubILE->getNumInits() == 0 && "explicit inits in array filler?");
    826       Init = SubILE->getArrayFiller();
    827     }
    828 
    829     // Switch back to initializing one base element at a time.
    830     CurPtr = Builder.CreateBitCast(CurPtr, BeginPtr->getType());
    831   }
    832 
    833   // Attempt to perform zero-initialization using memset.
    834   auto TryMemsetInitialization = [&]() -> bool {
    835     // FIXME: If the type is a pointer-to-data-member under the Itanium ABI,
    836     // we can initialize with a memset to -1.
    837     if (!CGM.getTypes().isZeroInitializable(ElementType))
    838       return false;
    839 
    840     // Optimization: since zero initialization will just set the memory
    841     // to all zeroes, generate a single memset to do it in one shot.
    842 
    843     // Subtract out the size of any elements we've already initialized.
    844     auto *RemainingSize = AllocSizeWithoutCookie;
    845     if (InitListElements) {
    846       // We know this can't overflow; we check this when doing the allocation.
    847       auto *InitializedSize = llvm::ConstantInt::get(
    848           RemainingSize->getType(),
    849           getContext().getTypeSizeInChars(ElementType).getQuantity() *
    850               InitListElements);
    851       RemainingSize = Builder.CreateSub(RemainingSize, InitializedSize);
    852     }
    853 
    854     // Create the memset.
    855     CharUnits Alignment = getContext().getTypeAlignInChars(ElementType);
    856     Builder.CreateMemSet(CurPtr, Builder.getInt8(0), RemainingSize,
    857                          Alignment.getQuantity(), false);
    858     return true;
    859   };
    860 
    861   // If all elements have already been initialized, skip any further
    862   // initialization.
    863   llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements);
    864   if (ConstNum && ConstNum->getZExtValue() <= InitListElements) {
    865     // If there was a Cleanup, deactivate it.
    866     if (CleanupDominator)
    867       DeactivateCleanupBlock(Cleanup, CleanupDominator);
    868     return;
    869   }
    870 
    871   assert(Init && "have trailing elements to initialize but no initializer");
    872 
    873   // If this is a constructor call, try to optimize it out, and failing that
    874   // emit a single loop to initialize all remaining elements.
    875   if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init)) {
    876     CXXConstructorDecl *Ctor = CCE->getConstructor();
    877     if (Ctor->isTrivial()) {
    878       // If new expression did not specify value-initialization, then there
    879       // is no initialization.
    880       if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty())
    881         return;
    882 
    883       if (TryMemsetInitialization())
    884         return;
    885     }
    886 
    887     // Store the new Cleanup position for irregular Cleanups.
    888     //
    889     // FIXME: Share this cleanup with the constructor call emission rather than
    890     // having it create a cleanup of its own.
    891     if (EndOfInit) Builder.CreateStore(CurPtr, EndOfInit);
    892 
    893     // Emit a constructor call loop to initialize the remaining elements.
    894     if (InitListElements)
    895       NumElements = Builder.CreateSub(
    896           NumElements,
    897           llvm::ConstantInt::get(NumElements->getType(), InitListElements));
    898     EmitCXXAggrConstructorCall(Ctor, NumElements, CurPtr,
    899                                CCE->arg_begin(), CCE->arg_end(),
    900                                CCE->requiresZeroInitialization());
    901     return;
    902   }
    903 
    904   // If this is value-initialization, we can usually use memset.
    905   ImplicitValueInitExpr IVIE(ElementType);
    906   if (isa<ImplicitValueInitExpr>(Init)) {
    907     if (TryMemsetInitialization())
    908       return;
    909 
    910     // Switch to an ImplicitValueInitExpr for the element type. This handles
    911     // only one case: multidimensional array new of pointers to members. In
    912     // all other cases, we already have an initializer for the array element.
    913     Init = &IVIE;
    914   }
    915 
    916   // At this point we should have found an initializer for the individual
    917   // elements of the array.
    918   assert(getContext().hasSameUnqualifiedType(ElementType, Init->getType()) &&
    919          "got wrong type of element to initialize");
    920 
    921   // If we have an empty initializer list, we can usually use memset.
    922   if (auto *ILE = dyn_cast<InitListExpr>(Init))
    923     if (ILE->getNumInits() == 0 && TryMemsetInitialization())
    924       return;
    925 
    926   // Create the loop blocks.
    927   llvm::BasicBlock *EntryBB = Builder.GetInsertBlock();
    928   llvm::BasicBlock *LoopBB = createBasicBlock("new.loop");
    929   llvm::BasicBlock *ContBB = createBasicBlock("new.loop.end");
    930 
    931   // Find the end of the array, hoisted out of the loop.
    932   llvm::Value *EndPtr =
    933     Builder.CreateInBoundsGEP(BeginPtr, NumElements, "array.end");
    934 
    935   // If the number of elements isn't constant, we have to now check if there is
    936   // anything left to initialize.
    937   if (!ConstNum) {
    938     llvm::Value *IsEmpty = Builder.CreateICmpEQ(CurPtr, EndPtr,
    939                                                 "array.isempty");
    940     Builder.CreateCondBr(IsEmpty, ContBB, LoopBB);
    941   }
    942 
    943   // Enter the loop.
    944   EmitBlock(LoopBB);
    945 
    946   // Set up the current-element phi.
    947   llvm::PHINode *CurPtrPhi =
    948     Builder.CreatePHI(CurPtr->getType(), 2, "array.cur");
    949   CurPtrPhi->addIncoming(CurPtr, EntryBB);
    950   CurPtr = CurPtrPhi;
    951 
    952   // Store the new Cleanup position for irregular Cleanups.
    953   if (EndOfInit) Builder.CreateStore(CurPtr, EndOfInit);
    954 
    955   // Enter a partial-destruction Cleanup if necessary.
    956   if (!CleanupDominator && needsEHCleanup(DtorKind)) {
    957     pushRegularPartialArrayCleanup(BeginPtr, CurPtr, ElementType,
    958                                    getDestroyer(DtorKind));
    959     Cleanup = EHStack.stable_begin();
    960     CleanupDominator = Builder.CreateUnreachable();
    961   }
    962 
    963   // Emit the initializer into this element.
    964   StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr);
    965 
    966   // Leave the Cleanup if we entered one.
    967   if (CleanupDominator) {
    968     DeactivateCleanupBlock(Cleanup, CleanupDominator);
    969     CleanupDominator->eraseFromParent();
    970   }
    971 
    972   // Advance to the next element by adjusting the pointer type as necessary.
    973   llvm::Value *NextPtr =
    974       Builder.CreateConstInBoundsGEP1_32(CurPtr, 1, "array.next");
    975 
    976   // Check whether we've gotten to the end of the array and, if so,
    977   // exit the loop.
    978   llvm::Value *IsEnd = Builder.CreateICmpEQ(NextPtr, EndPtr, "array.atend");
    979   Builder.CreateCondBr(IsEnd, ContBB, LoopBB);
    980   CurPtrPhi->addIncoming(NextPtr, Builder.GetInsertBlock());
    981 
    982   EmitBlock(ContBB);
    983 }
    984 
    985 static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E,
    986                                QualType ElementType,
    987                                llvm::Value *NewPtr,
    988                                llvm::Value *NumElements,
    989                                llvm::Value *AllocSizeWithoutCookie) {
    990   if (E->isArray())
    991     CGF.EmitNewArrayInitializer(E, ElementType, NewPtr, NumElements,
    992                                 AllocSizeWithoutCookie);
    993   else if (const Expr *Init = E->getInitializer())
    994     StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr);
    995 }
    996 
    997 /// Emit a call to an operator new or operator delete function, as implicitly
    998 /// created by new-expressions and delete-expressions.
    999 static RValue EmitNewDeleteCall(CodeGenFunction &CGF,
   1000                                 const FunctionDecl *Callee,
   1001                                 const FunctionProtoType *CalleeType,
   1002                                 const CallArgList &Args) {
   1003   llvm::Instruction *CallOrInvoke;
   1004   llvm::Value *CalleeAddr = CGF.CGM.GetAddrOfFunction(Callee);
   1005   RValue RV =
   1006       CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall(Args, CalleeType),
   1007                    CalleeAddr, ReturnValueSlot(), Args,
   1008                    Callee, &CallOrInvoke);
   1009 
   1010   /// C++1y [expr.new]p10:
   1011   ///   [In a new-expression,] an implementation is allowed to omit a call
   1012   ///   to a replaceable global allocation function.
   1013   ///
   1014   /// We model such elidable calls with the 'builtin' attribute.
   1015   llvm::Function *Fn = dyn_cast<llvm::Function>(CalleeAddr);
   1016   if (Callee->isReplaceableGlobalAllocationFunction() &&
   1017       Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) {
   1018     // FIXME: Add addAttribute to CallSite.
   1019     if (llvm::CallInst *CI = dyn_cast<llvm::CallInst>(CallOrInvoke))
   1020       CI->addAttribute(llvm::AttributeSet::FunctionIndex,
   1021                        llvm::Attribute::Builtin);
   1022     else if (llvm::InvokeInst *II = dyn_cast<llvm::InvokeInst>(CallOrInvoke))
   1023       II->addAttribute(llvm::AttributeSet::FunctionIndex,
   1024                        llvm::Attribute::Builtin);
   1025     else
   1026       llvm_unreachable("unexpected kind of call instruction");
   1027   }
   1028 
   1029   return RV;
   1030 }
   1031 
   1032 RValue CodeGenFunction::EmitBuiltinNewDeleteCall(const FunctionProtoType *Type,
   1033                                                  const Expr *Arg,
   1034                                                  bool IsDelete) {
   1035   CallArgList Args;
   1036   const Stmt *ArgS = Arg;
   1037   EmitCallArgs(Args, *Type->param_type_begin(),
   1038                ConstExprIterator(&ArgS), ConstExprIterator(&ArgS + 1));
   1039   // Find the allocation or deallocation function that we're calling.
   1040   ASTContext &Ctx = getContext();
   1041   DeclarationName Name = Ctx.DeclarationNames
   1042       .getCXXOperatorName(IsDelete ? OO_Delete : OO_New);
   1043   for (auto *Decl : Ctx.getTranslationUnitDecl()->lookup(Name))
   1044     if (auto *FD = dyn_cast<FunctionDecl>(Decl))
   1045       if (Ctx.hasSameType(FD->getType(), QualType(Type, 0)))
   1046         return EmitNewDeleteCall(*this, cast<FunctionDecl>(Decl), Type, Args);
   1047   llvm_unreachable("predeclared global operator new/delete is missing");
   1048 }
   1049 
   1050 namespace {
   1051   /// A cleanup to call the given 'operator delete' function upon
   1052   /// abnormal exit from a new expression.
   1053   class CallDeleteDuringNew : public EHScopeStack::Cleanup {
   1054     size_t NumPlacementArgs;
   1055     const FunctionDecl *OperatorDelete;
   1056     llvm::Value *Ptr;
   1057     llvm::Value *AllocSize;
   1058 
   1059     RValue *getPlacementArgs() { return reinterpret_cast<RValue*>(this+1); }
   1060 
   1061   public:
   1062     static size_t getExtraSize(size_t NumPlacementArgs) {
   1063       return NumPlacementArgs * sizeof(RValue);
   1064     }
   1065 
   1066     CallDeleteDuringNew(size_t NumPlacementArgs,
   1067                         const FunctionDecl *OperatorDelete,
   1068                         llvm::Value *Ptr,
   1069                         llvm::Value *AllocSize)
   1070       : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete),
   1071         Ptr(Ptr), AllocSize(AllocSize) {}
   1072 
   1073     void setPlacementArg(unsigned I, RValue Arg) {
   1074       assert(I < NumPlacementArgs && "index out of range");
   1075       getPlacementArgs()[I] = Arg;
   1076     }
   1077 
   1078     void Emit(CodeGenFunction &CGF, Flags flags) override {
   1079       const FunctionProtoType *FPT
   1080         = OperatorDelete->getType()->getAs<FunctionProtoType>();
   1081       assert(FPT->getNumParams() == NumPlacementArgs + 1 ||
   1082              (FPT->getNumParams() == 2 && NumPlacementArgs == 0));
   1083 
   1084       CallArgList DeleteArgs;
   1085 
   1086       // The first argument is always a void*.
   1087       FunctionProtoType::param_type_iterator AI = FPT->param_type_begin();
   1088       DeleteArgs.add(RValue::get(Ptr), *AI++);
   1089 
   1090       // A member 'operator delete' can take an extra 'size_t' argument.
   1091       if (FPT->getNumParams() == NumPlacementArgs + 2)
   1092         DeleteArgs.add(RValue::get(AllocSize), *AI++);
   1093 
   1094       // Pass the rest of the arguments, which must match exactly.
   1095       for (unsigned I = 0; I != NumPlacementArgs; ++I)
   1096         DeleteArgs.add(getPlacementArgs()[I], *AI++);
   1097 
   1098       // Call 'operator delete'.
   1099       EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs);
   1100     }
   1101   };
   1102 
   1103   /// A cleanup to call the given 'operator delete' function upon
   1104   /// abnormal exit from a new expression when the new expression is
   1105   /// conditional.
   1106   class CallDeleteDuringConditionalNew : public EHScopeStack::Cleanup {
   1107     size_t NumPlacementArgs;
   1108     const FunctionDecl *OperatorDelete;
   1109     DominatingValue<RValue>::saved_type Ptr;
   1110     DominatingValue<RValue>::saved_type AllocSize;
   1111 
   1112     DominatingValue<RValue>::saved_type *getPlacementArgs() {
   1113       return reinterpret_cast<DominatingValue<RValue>::saved_type*>(this+1);
   1114     }
   1115 
   1116   public:
   1117     static size_t getExtraSize(size_t NumPlacementArgs) {
   1118       return NumPlacementArgs * sizeof(DominatingValue<RValue>::saved_type);
   1119     }
   1120 
   1121     CallDeleteDuringConditionalNew(size_t NumPlacementArgs,
   1122                                    const FunctionDecl *OperatorDelete,
   1123                                    DominatingValue<RValue>::saved_type Ptr,
   1124                               DominatingValue<RValue>::saved_type AllocSize)
   1125       : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete),
   1126         Ptr(Ptr), AllocSize(AllocSize) {}
   1127 
   1128     void setPlacementArg(unsigned I, DominatingValue<RValue>::saved_type Arg) {
   1129       assert(I < NumPlacementArgs && "index out of range");
   1130       getPlacementArgs()[I] = Arg;
   1131     }
   1132 
   1133     void Emit(CodeGenFunction &CGF, Flags flags) override {
   1134       const FunctionProtoType *FPT
   1135         = OperatorDelete->getType()->getAs<FunctionProtoType>();
   1136       assert(FPT->getNumParams() == NumPlacementArgs + 1 ||
   1137              (FPT->getNumParams() == 2 && NumPlacementArgs == 0));
   1138 
   1139       CallArgList DeleteArgs;
   1140 
   1141       // The first argument is always a void*.
   1142       FunctionProtoType::param_type_iterator AI = FPT->param_type_begin();
   1143       DeleteArgs.add(Ptr.restore(CGF), *AI++);
   1144 
   1145       // A member 'operator delete' can take an extra 'size_t' argument.
   1146       if (FPT->getNumParams() == NumPlacementArgs + 2) {
   1147         RValue RV = AllocSize.restore(CGF);
   1148         DeleteArgs.add(RV, *AI++);
   1149       }
   1150 
   1151       // Pass the rest of the arguments, which must match exactly.
   1152       for (unsigned I = 0; I != NumPlacementArgs; ++I) {
   1153         RValue RV = getPlacementArgs()[I].restore(CGF);
   1154         DeleteArgs.add(RV, *AI++);
   1155       }
   1156 
   1157       // Call 'operator delete'.
   1158       EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs);
   1159     }
   1160   };
   1161 }
   1162 
   1163 /// Enter a cleanup to call 'operator delete' if the initializer in a
   1164 /// new-expression throws.
   1165 static void EnterNewDeleteCleanup(CodeGenFunction &CGF,
   1166                                   const CXXNewExpr *E,
   1167                                   llvm::Value *NewPtr,
   1168                                   llvm::Value *AllocSize,
   1169                                   const CallArgList &NewArgs) {
   1170   // If we're not inside a conditional branch, then the cleanup will
   1171   // dominate and we can do the easier (and more efficient) thing.
   1172   if (!CGF.isInConditionalBranch()) {
   1173     CallDeleteDuringNew *Cleanup = CGF.EHStack
   1174       .pushCleanupWithExtra<CallDeleteDuringNew>(EHCleanup,
   1175                                                  E->getNumPlacementArgs(),
   1176                                                  E->getOperatorDelete(),
   1177                                                  NewPtr, AllocSize);
   1178     for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I)
   1179       Cleanup->setPlacementArg(I, NewArgs[I+1].RV);
   1180 
   1181     return;
   1182   }
   1183 
   1184   // Otherwise, we need to save all this stuff.
   1185   DominatingValue<RValue>::saved_type SavedNewPtr =
   1186     DominatingValue<RValue>::save(CGF, RValue::get(NewPtr));
   1187   DominatingValue<RValue>::saved_type SavedAllocSize =
   1188     DominatingValue<RValue>::save(CGF, RValue::get(AllocSize));
   1189 
   1190   CallDeleteDuringConditionalNew *Cleanup = CGF.EHStack
   1191     .pushCleanupWithExtra<CallDeleteDuringConditionalNew>(EHCleanup,
   1192                                                  E->getNumPlacementArgs(),
   1193                                                  E->getOperatorDelete(),
   1194                                                  SavedNewPtr,
   1195                                                  SavedAllocSize);
   1196   for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I)
   1197     Cleanup->setPlacementArg(I,
   1198                      DominatingValue<RValue>::save(CGF, NewArgs[I+1].RV));
   1199 
   1200   CGF.initFullExprCleanup();
   1201 }
   1202 
   1203 llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) {
   1204   // The element type being allocated.
   1205   QualType allocType = getContext().getBaseElementType(E->getAllocatedType());
   1206 
   1207   // 1. Build a call to the allocation function.
   1208   FunctionDecl *allocator = E->getOperatorNew();
   1209   const FunctionProtoType *allocatorType =
   1210     allocator->getType()->castAs<FunctionProtoType>();
   1211 
   1212   CallArgList allocatorArgs;
   1213 
   1214   // The allocation size is the first argument.
   1215   QualType sizeType = getContext().getSizeType();
   1216 
   1217   // If there is a brace-initializer, cannot allocate fewer elements than inits.
   1218   unsigned minElements = 0;
   1219   if (E->isArray() && E->hasInitializer()) {
   1220     if (const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer()))
   1221       minElements = ILE->getNumInits();
   1222   }
   1223 
   1224   llvm::Value *numElements = nullptr;
   1225   llvm::Value *allocSizeWithoutCookie = nullptr;
   1226   llvm::Value *allocSize =
   1227     EmitCXXNewAllocSize(*this, E, minElements, numElements,
   1228                         allocSizeWithoutCookie);
   1229 
   1230   allocatorArgs.add(RValue::get(allocSize), sizeType);
   1231 
   1232   // We start at 1 here because the first argument (the allocation size)
   1233   // has already been emitted.
   1234   EmitCallArgs(allocatorArgs, allocatorType->isVariadic(),
   1235                allocatorType->param_type_begin() + 1,
   1236                allocatorType->param_type_end(), E->placement_arg_begin(),
   1237                E->placement_arg_end());
   1238 
   1239   // Emit the allocation call.  If the allocator is a global placement
   1240   // operator, just "inline" it directly.
   1241   RValue RV;
   1242   if (allocator->isReservedGlobalPlacementOperator()) {
   1243     assert(allocatorArgs.size() == 2);
   1244     RV = allocatorArgs[1].RV;
   1245     // TODO: kill any unnecessary computations done for the size
   1246     // argument.
   1247   } else {
   1248     RV = EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs);
   1249   }
   1250 
   1251   // Emit a null check on the allocation result if the allocation
   1252   // function is allowed to return null (because it has a non-throwing
   1253   // exception spec; for this part, we inline
   1254   // CXXNewExpr::shouldNullCheckAllocation()) and we have an
   1255   // interesting initializer.
   1256   bool nullCheck = allocatorType->isNothrow(getContext()) &&
   1257     (!allocType.isPODType(getContext()) || E->hasInitializer());
   1258 
   1259   llvm::BasicBlock *nullCheckBB = nullptr;
   1260   llvm::BasicBlock *contBB = nullptr;
   1261 
   1262   llvm::Value *allocation = RV.getScalarVal();
   1263   unsigned AS = allocation->getType()->getPointerAddressSpace();
   1264 
   1265   // The null-check means that the initializer is conditionally
   1266   // evaluated.
   1267   ConditionalEvaluation conditional(*this);
   1268 
   1269   if (nullCheck) {
   1270     conditional.begin(*this);
   1271 
   1272     nullCheckBB = Builder.GetInsertBlock();
   1273     llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull");
   1274     contBB = createBasicBlock("new.cont");
   1275 
   1276     llvm::Value *isNull = Builder.CreateIsNull(allocation, "new.isnull");
   1277     Builder.CreateCondBr(isNull, contBB, notNullBB);
   1278     EmitBlock(notNullBB);
   1279   }
   1280 
   1281   // If there's an operator delete, enter a cleanup to call it if an
   1282   // exception is thrown.
   1283   EHScopeStack::stable_iterator operatorDeleteCleanup;
   1284   llvm::Instruction *cleanupDominator = nullptr;
   1285   if (E->getOperatorDelete() &&
   1286       !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
   1287     EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocatorArgs);
   1288     operatorDeleteCleanup = EHStack.stable_begin();
   1289     cleanupDominator = Builder.CreateUnreachable();
   1290   }
   1291 
   1292   assert((allocSize == allocSizeWithoutCookie) ==
   1293          CalculateCookiePadding(*this, E).isZero());
   1294   if (allocSize != allocSizeWithoutCookie) {
   1295     assert(E->isArray());
   1296     allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation,
   1297                                                        numElements,
   1298                                                        E, allocType);
   1299   }
   1300 
   1301   llvm::Type *elementPtrTy
   1302     = ConvertTypeForMem(allocType)->getPointerTo(AS);
   1303   llvm::Value *result = Builder.CreateBitCast(allocation, elementPtrTy);
   1304 
   1305   EmitNewInitializer(*this, E, allocType, result, numElements,
   1306                      allocSizeWithoutCookie);
   1307   if (E->isArray()) {
   1308     // NewPtr is a pointer to the base element type.  If we're
   1309     // allocating an array of arrays, we'll need to cast back to the
   1310     // array pointer type.
   1311     llvm::Type *resultType = ConvertTypeForMem(E->getType());
   1312     if (result->getType() != resultType)
   1313       result = Builder.CreateBitCast(result, resultType);
   1314   }
   1315 
   1316   // Deactivate the 'operator delete' cleanup if we finished
   1317   // initialization.
   1318   if (operatorDeleteCleanup.isValid()) {
   1319     DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator);
   1320     cleanupDominator->eraseFromParent();
   1321   }
   1322 
   1323   if (nullCheck) {
   1324     conditional.end(*this);
   1325 
   1326     llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
   1327     EmitBlock(contBB);
   1328 
   1329     llvm::PHINode *PHI = Builder.CreatePHI(result->getType(), 2);
   1330     PHI->addIncoming(result, notNullBB);
   1331     PHI->addIncoming(llvm::Constant::getNullValue(result->getType()),
   1332                      nullCheckBB);
   1333 
   1334     result = PHI;
   1335   }
   1336 
   1337   return result;
   1338 }
   1339 
   1340 void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD,
   1341                                      llvm::Value *Ptr,
   1342                                      QualType DeleteTy) {
   1343   assert(DeleteFD->getOverloadedOperator() == OO_Delete);
   1344 
   1345   const FunctionProtoType *DeleteFTy =
   1346     DeleteFD->getType()->getAs<FunctionProtoType>();
   1347 
   1348   CallArgList DeleteArgs;
   1349 
   1350   // Check if we need to pass the size to the delete operator.
   1351   llvm::Value *Size = nullptr;
   1352   QualType SizeTy;
   1353   if (DeleteFTy->getNumParams() == 2) {
   1354     SizeTy = DeleteFTy->getParamType(1);
   1355     CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy);
   1356     Size = llvm::ConstantInt::get(ConvertType(SizeTy),
   1357                                   DeleteTypeSize.getQuantity());
   1358   }
   1359 
   1360   QualType ArgTy = DeleteFTy->getParamType(0);
   1361   llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy));
   1362   DeleteArgs.add(RValue::get(DeletePtr), ArgTy);
   1363 
   1364   if (Size)
   1365     DeleteArgs.add(RValue::get(Size), SizeTy);
   1366 
   1367   // Emit the call to delete.
   1368   EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs);
   1369 }
   1370 
   1371 namespace {
   1372   /// Calls the given 'operator delete' on a single object.
   1373   struct CallObjectDelete : EHScopeStack::Cleanup {
   1374     llvm::Value *Ptr;
   1375     const FunctionDecl *OperatorDelete;
   1376     QualType ElementType;
   1377 
   1378     CallObjectDelete(llvm::Value *Ptr,
   1379                      const FunctionDecl *OperatorDelete,
   1380                      QualType ElementType)
   1381       : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {}
   1382 
   1383     void Emit(CodeGenFunction &CGF, Flags flags) override {
   1384       CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType);
   1385     }
   1386   };
   1387 }
   1388 
   1389 /// Emit the code for deleting a single object.
   1390 static void EmitObjectDelete(CodeGenFunction &CGF,
   1391                              const FunctionDecl *OperatorDelete,
   1392                              llvm::Value *Ptr,
   1393                              QualType ElementType,
   1394                              bool UseGlobalDelete) {
   1395   // Find the destructor for the type, if applicable.  If the
   1396   // destructor is virtual, we'll just emit the vcall and return.
   1397   const CXXDestructorDecl *Dtor = nullptr;
   1398   if (const RecordType *RT = ElementType->getAs<RecordType>()) {
   1399     CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
   1400     if (RD->hasDefinition() && !RD->hasTrivialDestructor()) {
   1401       Dtor = RD->getDestructor();
   1402 
   1403       if (Dtor->isVirtual()) {
   1404         if (UseGlobalDelete) {
   1405           // If we're supposed to call the global delete, make sure we do so
   1406           // even if the destructor throws.
   1407 
   1408           // Derive the complete-object pointer, which is what we need
   1409           // to pass to the deallocation function.
   1410           llvm::Value *completePtr =
   1411             CGF.CGM.getCXXABI().adjustToCompleteObject(CGF, Ptr, ElementType);
   1412 
   1413           CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
   1414                                                     completePtr, OperatorDelete,
   1415                                                     ElementType);
   1416         }
   1417 
   1418         // FIXME: Provide a source location here.
   1419         CXXDtorType DtorType = UseGlobalDelete ? Dtor_Complete : Dtor_Deleting;
   1420         CGF.CGM.getCXXABI().EmitVirtualDestructorCall(CGF, Dtor, DtorType,
   1421                                                       SourceLocation(), Ptr);
   1422 
   1423         if (UseGlobalDelete) {
   1424           CGF.PopCleanupBlock();
   1425         }
   1426 
   1427         return;
   1428       }
   1429     }
   1430   }
   1431 
   1432   // Make sure that we call delete even if the dtor throws.
   1433   // This doesn't have to a conditional cleanup because we're going
   1434   // to pop it off in a second.
   1435   CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
   1436                                             Ptr, OperatorDelete, ElementType);
   1437 
   1438   if (Dtor)
   1439     CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
   1440                               /*ForVirtualBase=*/false,
   1441                               /*Delegating=*/false,
   1442                               Ptr);
   1443   else if (CGF.getLangOpts().ObjCAutoRefCount &&
   1444            ElementType->isObjCLifetimeType()) {
   1445     switch (ElementType.getObjCLifetime()) {
   1446     case Qualifiers::OCL_None:
   1447     case Qualifiers::OCL_ExplicitNone:
   1448     case Qualifiers::OCL_Autoreleasing:
   1449       break;
   1450 
   1451     case Qualifiers::OCL_Strong: {
   1452       // Load the pointer value.
   1453       llvm::Value *PtrValue = CGF.Builder.CreateLoad(Ptr,
   1454                                              ElementType.isVolatileQualified());
   1455 
   1456       CGF.EmitARCRelease(PtrValue, ARCPreciseLifetime);
   1457       break;
   1458     }
   1459 
   1460     case Qualifiers::OCL_Weak:
   1461       CGF.EmitARCDestroyWeak(Ptr);
   1462       break;
   1463     }
   1464   }
   1465 
   1466   CGF.PopCleanupBlock();
   1467 }
   1468 
   1469 namespace {
   1470   /// Calls the given 'operator delete' on an array of objects.
   1471   struct CallArrayDelete : EHScopeStack::Cleanup {
   1472     llvm::Value *Ptr;
   1473     const FunctionDecl *OperatorDelete;
   1474     llvm::Value *NumElements;
   1475     QualType ElementType;
   1476     CharUnits CookieSize;
   1477 
   1478     CallArrayDelete(llvm::Value *Ptr,
   1479                     const FunctionDecl *OperatorDelete,
   1480                     llvm::Value *NumElements,
   1481                     QualType ElementType,
   1482                     CharUnits CookieSize)
   1483       : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements),
   1484         ElementType(ElementType), CookieSize(CookieSize) {}
   1485 
   1486     void Emit(CodeGenFunction &CGF, Flags flags) override {
   1487       const FunctionProtoType *DeleteFTy =
   1488         OperatorDelete->getType()->getAs<FunctionProtoType>();
   1489       assert(DeleteFTy->getNumParams() == 1 || DeleteFTy->getNumParams() == 2);
   1490 
   1491       CallArgList Args;
   1492 
   1493       // Pass the pointer as the first argument.
   1494       QualType VoidPtrTy = DeleteFTy->getParamType(0);
   1495       llvm::Value *DeletePtr
   1496         = CGF.Builder.CreateBitCast(Ptr, CGF.ConvertType(VoidPtrTy));
   1497       Args.add(RValue::get(DeletePtr), VoidPtrTy);
   1498 
   1499       // Pass the original requested size as the second argument.
   1500       if (DeleteFTy->getNumParams() == 2) {
   1501         QualType size_t = DeleteFTy->getParamType(1);
   1502         llvm::IntegerType *SizeTy
   1503           = cast<llvm::IntegerType>(CGF.ConvertType(size_t));
   1504 
   1505         CharUnits ElementTypeSize =
   1506           CGF.CGM.getContext().getTypeSizeInChars(ElementType);
   1507 
   1508         // The size of an element, multiplied by the number of elements.
   1509         llvm::Value *Size
   1510           = llvm::ConstantInt::get(SizeTy, ElementTypeSize.getQuantity());
   1511         Size = CGF.Builder.CreateMul(Size, NumElements);
   1512 
   1513         // Plus the size of the cookie if applicable.
   1514         if (!CookieSize.isZero()) {
   1515           llvm::Value *CookieSizeV
   1516             = llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity());
   1517           Size = CGF.Builder.CreateAdd(Size, CookieSizeV);
   1518         }
   1519 
   1520         Args.add(RValue::get(Size), size_t);
   1521       }
   1522 
   1523       // Emit the call to delete.
   1524       EmitNewDeleteCall(CGF, OperatorDelete, DeleteFTy, Args);
   1525     }
   1526   };
   1527 }
   1528 
   1529 /// Emit the code for deleting an array of objects.
   1530 static void EmitArrayDelete(CodeGenFunction &CGF,
   1531                             const CXXDeleteExpr *E,
   1532                             llvm::Value *deletedPtr,
   1533                             QualType elementType) {
   1534   llvm::Value *numElements = nullptr;
   1535   llvm::Value *allocatedPtr = nullptr;
   1536   CharUnits cookieSize;
   1537   CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType,
   1538                                       numElements, allocatedPtr, cookieSize);
   1539 
   1540   assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer");
   1541 
   1542   // Make sure that we call delete even if one of the dtors throws.
   1543   const FunctionDecl *operatorDelete = E->getOperatorDelete();
   1544   CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup,
   1545                                            allocatedPtr, operatorDelete,
   1546                                            numElements, elementType,
   1547                                            cookieSize);
   1548 
   1549   // Destroy the elements.
   1550   if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) {
   1551     assert(numElements && "no element count for a type with a destructor!");
   1552 
   1553     llvm::Value *arrayEnd =
   1554       CGF.Builder.CreateInBoundsGEP(deletedPtr, numElements, "delete.end");
   1555 
   1556     // Note that it is legal to allocate a zero-length array, and we
   1557     // can never fold the check away because the length should always
   1558     // come from a cookie.
   1559     CGF.emitArrayDestroy(deletedPtr, arrayEnd, elementType,
   1560                          CGF.getDestroyer(dtorKind),
   1561                          /*checkZeroLength*/ true,
   1562                          CGF.needsEHCleanup(dtorKind));
   1563   }
   1564 
   1565   // Pop the cleanup block.
   1566   CGF.PopCleanupBlock();
   1567 }
   1568 
   1569 void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) {
   1570   const Expr *Arg = E->getArgument();
   1571   llvm::Value *Ptr = EmitScalarExpr(Arg);
   1572 
   1573   // Null check the pointer.
   1574   llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull");
   1575   llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end");
   1576 
   1577   llvm::Value *IsNull = Builder.CreateIsNull(Ptr, "isnull");
   1578 
   1579   Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull);
   1580   EmitBlock(DeleteNotNull);
   1581 
   1582   // We might be deleting a pointer to array.  If so, GEP down to the
   1583   // first non-array element.
   1584   // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*)
   1585   QualType DeleteTy = Arg->getType()->getAs<PointerType>()->getPointeeType();
   1586   if (DeleteTy->isConstantArrayType()) {
   1587     llvm::Value *Zero = Builder.getInt32(0);
   1588     SmallVector<llvm::Value*,8> GEP;
   1589 
   1590     GEP.push_back(Zero); // point at the outermost array
   1591 
   1592     // For each layer of array type we're pointing at:
   1593     while (const ConstantArrayType *Arr
   1594              = getContext().getAsConstantArrayType(DeleteTy)) {
   1595       // 1. Unpeel the array type.
   1596       DeleteTy = Arr->getElementType();
   1597 
   1598       // 2. GEP to the first element of the array.
   1599       GEP.push_back(Zero);
   1600     }
   1601 
   1602     Ptr = Builder.CreateInBoundsGEP(Ptr, GEP, "del.first");
   1603   }
   1604 
   1605   assert(ConvertTypeForMem(DeleteTy) ==
   1606          cast<llvm::PointerType>(Ptr->getType())->getElementType());
   1607 
   1608   if (E->isArrayForm()) {
   1609     EmitArrayDelete(*this, E, Ptr, DeleteTy);
   1610   } else {
   1611     EmitObjectDelete(*this, E->getOperatorDelete(), Ptr, DeleteTy,
   1612                      E->isGlobalDelete());
   1613   }
   1614 
   1615   EmitBlock(DeleteEnd);
   1616 }
   1617 
   1618 static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, const Expr *E,
   1619                                          llvm::Type *StdTypeInfoPtrTy) {
   1620   // Get the vtable pointer.
   1621   llvm::Value *ThisPtr = CGF.EmitLValue(E).getAddress();
   1622 
   1623   // C++ [expr.typeid]p2:
   1624   //   If the glvalue expression is obtained by applying the unary * operator to
   1625   //   a pointer and the pointer is a null pointer value, the typeid expression
   1626   //   throws the std::bad_typeid exception.
   1627   bool IsDeref = false;
   1628   if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParens()))
   1629     if (UO->getOpcode() == UO_Deref)
   1630       IsDeref = true;
   1631 
   1632   QualType SrcRecordTy = E->getType();
   1633   if (CGF.CGM.getCXXABI().shouldTypeidBeNullChecked(IsDeref, SrcRecordTy)) {
   1634     llvm::BasicBlock *BadTypeidBlock =
   1635         CGF.createBasicBlock("typeid.bad_typeid");
   1636     llvm::BasicBlock *EndBlock = CGF.createBasicBlock("typeid.end");
   1637 
   1638     llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr);
   1639     CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock);
   1640 
   1641     CGF.EmitBlock(BadTypeidBlock);
   1642     CGF.CGM.getCXXABI().EmitBadTypeidCall(CGF);
   1643     CGF.EmitBlock(EndBlock);
   1644   }
   1645 
   1646   return CGF.CGM.getCXXABI().EmitTypeid(CGF, SrcRecordTy, ThisPtr,
   1647                                         StdTypeInfoPtrTy);
   1648 }
   1649 
   1650 llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) {
   1651   llvm::Type *StdTypeInfoPtrTy =
   1652     ConvertType(E->getType())->getPointerTo();
   1653 
   1654   if (E->isTypeOperand()) {
   1655     llvm::Constant *TypeInfo =
   1656         CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand(getContext()));
   1657     return Builder.CreateBitCast(TypeInfo, StdTypeInfoPtrTy);
   1658   }
   1659 
   1660   // C++ [expr.typeid]p2:
   1661   //   When typeid is applied to a glvalue expression whose type is a
   1662   //   polymorphic class type, the result refers to a std::type_info object
   1663   //   representing the type of the most derived object (that is, the dynamic
   1664   //   type) to which the glvalue refers.
   1665   if (E->isPotentiallyEvaluated())
   1666     return EmitTypeidFromVTable(*this, E->getExprOperand(),
   1667                                 StdTypeInfoPtrTy);
   1668 
   1669   QualType OperandTy = E->getExprOperand()->getType();
   1670   return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy),
   1671                                StdTypeInfoPtrTy);
   1672 }
   1673 
   1674 static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF,
   1675                                           QualType DestTy) {
   1676   llvm::Type *DestLTy = CGF.ConvertType(DestTy);
   1677   if (DestTy->isPointerType())
   1678     return llvm::Constant::getNullValue(DestLTy);
   1679 
   1680   /// C++ [expr.dynamic.cast]p9:
   1681   ///   A failed cast to reference type throws std::bad_cast
   1682   if (!CGF.CGM.getCXXABI().EmitBadCastCall(CGF))
   1683     return nullptr;
   1684 
   1685   CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end"));
   1686   return llvm::UndefValue::get(DestLTy);
   1687 }
   1688 
   1689 llvm::Value *CodeGenFunction::EmitDynamicCast(llvm::Value *Value,
   1690                                               const CXXDynamicCastExpr *DCE) {
   1691   QualType DestTy = DCE->getTypeAsWritten();
   1692 
   1693   if (DCE->isAlwaysNull())
   1694     if (llvm::Value *T = EmitDynamicCastToNull(*this, DestTy))
   1695       return T;
   1696 
   1697   QualType SrcTy = DCE->getSubExpr()->getType();
   1698 
   1699   // C++ [expr.dynamic.cast]p7:
   1700   //   If T is "pointer to cv void," then the result is a pointer to the most
   1701   //   derived object pointed to by v.
   1702   const PointerType *DestPTy = DestTy->getAs<PointerType>();
   1703 
   1704   bool isDynamicCastToVoid;
   1705   QualType SrcRecordTy;
   1706   QualType DestRecordTy;
   1707   if (DestPTy) {
   1708     isDynamicCastToVoid = DestPTy->getPointeeType()->isVoidType();
   1709     SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType();
   1710     DestRecordTy = DestPTy->getPointeeType();
   1711   } else {
   1712     isDynamicCastToVoid = false;
   1713     SrcRecordTy = SrcTy;
   1714     DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType();
   1715   }
   1716 
   1717   assert(SrcRecordTy->isRecordType() && "source type must be a record type!");
   1718 
   1719   // C++ [expr.dynamic.cast]p4:
   1720   //   If the value of v is a null pointer value in the pointer case, the result
   1721   //   is the null pointer value of type T.
   1722   bool ShouldNullCheckSrcValue =
   1723       CGM.getCXXABI().shouldDynamicCastCallBeNullChecked(SrcTy->isPointerType(),
   1724                                                          SrcRecordTy);
   1725 
   1726   llvm::BasicBlock *CastNull = nullptr;
   1727   llvm::BasicBlock *CastNotNull = nullptr;
   1728   llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end");
   1729 
   1730   if (ShouldNullCheckSrcValue) {
   1731     CastNull = createBasicBlock("dynamic_cast.null");
   1732     CastNotNull = createBasicBlock("dynamic_cast.notnull");
   1733 
   1734     llvm::Value *IsNull = Builder.CreateIsNull(Value);
   1735     Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
   1736     EmitBlock(CastNotNull);
   1737   }
   1738 
   1739   if (isDynamicCastToVoid) {
   1740     Value = CGM.getCXXABI().EmitDynamicCastToVoid(*this, Value, SrcRecordTy,
   1741                                                   DestTy);
   1742   } else {
   1743     assert(DestRecordTy->isRecordType() &&
   1744            "destination type must be a record type!");
   1745     Value = CGM.getCXXABI().EmitDynamicCastCall(*this, Value, SrcRecordTy,
   1746                                                 DestTy, DestRecordTy, CastEnd);
   1747   }
   1748 
   1749   if (ShouldNullCheckSrcValue) {
   1750     EmitBranch(CastEnd);
   1751 
   1752     EmitBlock(CastNull);
   1753     EmitBranch(CastEnd);
   1754   }
   1755 
   1756   EmitBlock(CastEnd);
   1757 
   1758   if (ShouldNullCheckSrcValue) {
   1759     llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
   1760     PHI->addIncoming(Value, CastNotNull);
   1761     PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull);
   1762 
   1763     Value = PHI;
   1764   }
   1765 
   1766   return Value;
   1767 }
   1768 
   1769 void CodeGenFunction::EmitLambdaExpr(const LambdaExpr *E, AggValueSlot Slot) {
   1770   RunCleanupsScope Scope(*this);
   1771   LValue SlotLV = MakeAddrLValue(Slot.getAddr(), E->getType(),
   1772                                  Slot.getAlignment());
   1773 
   1774   CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin();
   1775   for (LambdaExpr::capture_init_iterator i = E->capture_init_begin(),
   1776                                          e = E->capture_init_end();
   1777        i != e; ++i, ++CurField) {
   1778     // Emit initialization
   1779 
   1780     LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
   1781     ArrayRef<VarDecl *> ArrayIndexes;
   1782     if (CurField->getType()->isArrayType())
   1783       ArrayIndexes = E->getCaptureInitIndexVars(i);
   1784     EmitInitializerForField(*CurField, LV, *i, ArrayIndexes);
   1785   }
   1786 }
   1787