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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 "clang/Frontend/CodeGenOptions.h"
     15 #include "CodeGenFunction.h"
     16 #include "CGCUDARuntime.h"
     17 #include "CGCXXABI.h"
     18 #include "CGObjCRuntime.h"
     19 #include "CGDebugInfo.h"
     20 #include "llvm/Intrinsics.h"
     21 #include "llvm/Support/CallSite.h"
     22 
     23 using namespace clang;
     24 using namespace CodeGen;
     25 
     26 RValue CodeGenFunction::EmitCXXMemberCall(const CXXMethodDecl *MD,
     27                                           llvm::Value *Callee,
     28                                           ReturnValueSlot ReturnValue,
     29                                           llvm::Value *This,
     30                                           llvm::Value *VTT,
     31                                           CallExpr::const_arg_iterator ArgBeg,
     32                                           CallExpr::const_arg_iterator ArgEnd) {
     33   assert(MD->isInstance() &&
     34          "Trying to emit a member call expr on a static method!");
     35 
     36   CallArgList Args;
     37 
     38   // Push the this ptr.
     39   Args.add(RValue::get(This), MD->getThisType(getContext()));
     40 
     41   // If there is a VTT parameter, emit it.
     42   if (VTT) {
     43     QualType T = getContext().getPointerType(getContext().VoidPtrTy);
     44     Args.add(RValue::get(VTT), T);
     45   }
     46 
     47   const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
     48   RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size());
     49 
     50   // And the rest of the call args.
     51   EmitCallArgs(Args, FPT, ArgBeg, ArgEnd);
     52 
     53   return EmitCall(CGM.getTypes().arrangeFunctionCall(FPT->getResultType(), Args,
     54                                                      FPT->getExtInfo(),
     55                                                      required),
     56                   Callee, ReturnValue, Args, MD);
     57 }
     58 
     59 static const CXXRecordDecl *getMostDerivedClassDecl(const Expr *Base) {
     60   const Expr *E = Base;
     61 
     62   while (true) {
     63     E = E->IgnoreParens();
     64     if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
     65       if (CE->getCastKind() == CK_DerivedToBase ||
     66           CE->getCastKind() == CK_UncheckedDerivedToBase ||
     67           CE->getCastKind() == CK_NoOp) {
     68         E = CE->getSubExpr();
     69         continue;
     70       }
     71     }
     72 
     73     break;
     74   }
     75 
     76   QualType DerivedType = E->getType();
     77   if (const PointerType *PTy = DerivedType->getAs<PointerType>())
     78     DerivedType = PTy->getPointeeType();
     79 
     80   return cast<CXXRecordDecl>(DerivedType->castAs<RecordType>()->getDecl());
     81 }
     82 
     83 // FIXME: Ideally Expr::IgnoreParenNoopCasts should do this, but it doesn't do
     84 // quite what we want.
     85 static const Expr *skipNoOpCastsAndParens(const Expr *E) {
     86   while (true) {
     87     if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
     88       E = PE->getSubExpr();
     89       continue;
     90     }
     91 
     92     if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
     93       if (CE->getCastKind() == CK_NoOp) {
     94         E = CE->getSubExpr();
     95         continue;
     96       }
     97     }
     98     if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
     99       if (UO->getOpcode() == UO_Extension) {
    100         E = UO->getSubExpr();
    101         continue;
    102       }
    103     }
    104     return E;
    105   }
    106 }
    107 
    108 /// canDevirtualizeMemberFunctionCalls - Checks whether virtual calls on given
    109 /// expr can be devirtualized.
    110 static bool canDevirtualizeMemberFunctionCalls(ASTContext &Context,
    111                                                const Expr *Base,
    112                                                const CXXMethodDecl *MD) {
    113 
    114   // When building with -fapple-kext, all calls must go through the vtable since
    115   // the kernel linker can do runtime patching of vtables.
    116   if (Context.getLangOpts().AppleKext)
    117     return false;
    118 
    119   // If the most derived class is marked final, we know that no subclass can
    120   // override this member function and so we can devirtualize it. For example:
    121   //
    122   // struct A { virtual void f(); }
    123   // struct B final : A { };
    124   //
    125   // void f(B *b) {
    126   //   b->f();
    127   // }
    128   //
    129   const CXXRecordDecl *MostDerivedClassDecl = getMostDerivedClassDecl(Base);
    130   if (MostDerivedClassDecl->hasAttr<FinalAttr>())
    131     return true;
    132 
    133   // If the member function is marked 'final', we know that it can't be
    134   // overridden and can therefore devirtualize it.
    135   if (MD->hasAttr<FinalAttr>())
    136     return true;
    137 
    138   // Similarly, if the class itself is marked 'final' it can't be overridden
    139   // and we can therefore devirtualize the member function call.
    140   if (MD->getParent()->hasAttr<FinalAttr>())
    141     return true;
    142 
    143   Base = skipNoOpCastsAndParens(Base);
    144   if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) {
    145     if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
    146       // This is a record decl. We know the type and can devirtualize it.
    147       return VD->getType()->isRecordType();
    148     }
    149 
    150     return false;
    151   }
    152 
    153   // We can always devirtualize calls on temporary object expressions.
    154   if (isa<CXXConstructExpr>(Base))
    155     return true;
    156 
    157   // And calls on bound temporaries.
    158   if (isa<CXXBindTemporaryExpr>(Base))
    159     return true;
    160 
    161   // Check if this is a call expr that returns a record type.
    162   if (const CallExpr *CE = dyn_cast<CallExpr>(Base))
    163     return CE->getCallReturnType()->isRecordType();
    164 
    165   // We can't devirtualize the call.
    166   return false;
    167 }
    168 
    169 // Note: This function also emit constructor calls to support a MSVC
    170 // extensions allowing explicit constructor function call.
    171 RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE,
    172                                               ReturnValueSlot ReturnValue) {
    173   const Expr *callee = CE->getCallee()->IgnoreParens();
    174 
    175   if (isa<BinaryOperator>(callee))
    176     return EmitCXXMemberPointerCallExpr(CE, ReturnValue);
    177 
    178   const MemberExpr *ME = cast<MemberExpr>(callee);
    179   const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl());
    180 
    181   CGDebugInfo *DI = getDebugInfo();
    182   if (DI && CGM.getCodeGenOpts().LimitDebugInfo
    183       && !isa<CallExpr>(ME->getBase())) {
    184     QualType PQTy = ME->getBase()->IgnoreParenImpCasts()->getType();
    185     if (const PointerType * PTy = dyn_cast<PointerType>(PQTy)) {
    186       DI->getOrCreateRecordType(PTy->getPointeeType(),
    187                                 MD->getParent()->getLocation());
    188     }
    189   }
    190 
    191   if (MD->isStatic()) {
    192     // The method is static, emit it as we would a regular call.
    193     llvm::Value *Callee = CGM.GetAddrOfFunction(MD);
    194     return EmitCall(getContext().getPointerType(MD->getType()), Callee,
    195                     ReturnValue, CE->arg_begin(), CE->arg_end());
    196   }
    197 
    198   // Compute the object pointer.
    199   llvm::Value *This;
    200   if (ME->isArrow())
    201     This = EmitScalarExpr(ME->getBase());
    202   else
    203     This = EmitLValue(ME->getBase()).getAddress();
    204 
    205   if (MD->isTrivial()) {
    206     if (isa<CXXDestructorDecl>(MD)) return RValue::get(0);
    207     if (isa<CXXConstructorDecl>(MD) &&
    208         cast<CXXConstructorDecl>(MD)->isDefaultConstructor())
    209       return RValue::get(0);
    210 
    211     if (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) {
    212       // We don't like to generate the trivial copy/move assignment operator
    213       // when it isn't necessary; just produce the proper effect here.
    214       llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress();
    215       EmitAggregateCopy(This, RHS, CE->getType());
    216       return RValue::get(This);
    217     }
    218 
    219     if (isa<CXXConstructorDecl>(MD) &&
    220         cast<CXXConstructorDecl>(MD)->isCopyOrMoveConstructor()) {
    221       // Trivial move and copy ctor are the same.
    222       llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress();
    223       EmitSynthesizedCXXCopyCtorCall(cast<CXXConstructorDecl>(MD), This, RHS,
    224                                      CE->arg_begin(), CE->arg_end());
    225       return RValue::get(This);
    226     }
    227     llvm_unreachable("unknown trivial member function");
    228   }
    229 
    230   // Compute the function type we're calling.
    231   const CGFunctionInfo *FInfo = 0;
    232   if (isa<CXXDestructorDecl>(MD))
    233     FInfo = &CGM.getTypes().arrangeCXXDestructor(cast<CXXDestructorDecl>(MD),
    234                                                  Dtor_Complete);
    235   else if (isa<CXXConstructorDecl>(MD))
    236     FInfo = &CGM.getTypes().arrangeCXXConstructorDeclaration(
    237                                                  cast<CXXConstructorDecl>(MD),
    238                                                  Ctor_Complete);
    239   else
    240     FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(MD);
    241 
    242   llvm::Type *Ty = CGM.getTypes().GetFunctionType(*FInfo);
    243 
    244   // C++ [class.virtual]p12:
    245   //   Explicit qualification with the scope operator (5.1) suppresses the
    246   //   virtual call mechanism.
    247   //
    248   // We also don't emit a virtual call if the base expression has a record type
    249   // because then we know what the type is.
    250   bool UseVirtualCall;
    251   UseVirtualCall = MD->isVirtual() && !ME->hasQualifier()
    252                    && !canDevirtualizeMemberFunctionCalls(getContext(),
    253                                                           ME->getBase(), MD);
    254   llvm::Value *Callee;
    255   if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(MD)) {
    256     if (UseVirtualCall) {
    257       Callee = BuildVirtualCall(Dtor, Dtor_Complete, This, Ty);
    258     } else {
    259       if (getContext().getLangOpts().AppleKext &&
    260           MD->isVirtual() &&
    261           ME->hasQualifier())
    262         Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty);
    263       else
    264         Callee = CGM.GetAddrOfFunction(GlobalDecl(Dtor, Dtor_Complete), Ty);
    265     }
    266   } else if (const CXXConstructorDecl *Ctor =
    267                dyn_cast<CXXConstructorDecl>(MD)) {
    268     Callee = CGM.GetAddrOfFunction(GlobalDecl(Ctor, Ctor_Complete), Ty);
    269   } else if (UseVirtualCall) {
    270       Callee = BuildVirtualCall(MD, This, Ty);
    271   } else {
    272     if (getContext().getLangOpts().AppleKext &&
    273         MD->isVirtual() &&
    274         ME->hasQualifier())
    275       Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty);
    276     else
    277       Callee = CGM.GetAddrOfFunction(MD, Ty);
    278   }
    279 
    280   return EmitCXXMemberCall(MD, Callee, ReturnValue, This, /*VTT=*/0,
    281                            CE->arg_begin(), CE->arg_end());
    282 }
    283 
    284 RValue
    285 CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E,
    286                                               ReturnValueSlot ReturnValue) {
    287   const BinaryOperator *BO =
    288       cast<BinaryOperator>(E->getCallee()->IgnoreParens());
    289   const Expr *BaseExpr = BO->getLHS();
    290   const Expr *MemFnExpr = BO->getRHS();
    291 
    292   const MemberPointerType *MPT =
    293     MemFnExpr->getType()->castAs<MemberPointerType>();
    294 
    295   const FunctionProtoType *FPT =
    296     MPT->getPointeeType()->castAs<FunctionProtoType>();
    297   const CXXRecordDecl *RD =
    298     cast<CXXRecordDecl>(MPT->getClass()->getAs<RecordType>()->getDecl());
    299 
    300   // Get the member function pointer.
    301   llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr);
    302 
    303   // Emit the 'this' pointer.
    304   llvm::Value *This;
    305 
    306   if (BO->getOpcode() == BO_PtrMemI)
    307     This = EmitScalarExpr(BaseExpr);
    308   else
    309     This = EmitLValue(BaseExpr).getAddress();
    310 
    311   // Ask the ABI to load the callee.  Note that This is modified.
    312   llvm::Value *Callee =
    313     CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, This, MemFnPtr, MPT);
    314 
    315   CallArgList Args;
    316 
    317   QualType ThisType =
    318     getContext().getPointerType(getContext().getTagDeclType(RD));
    319 
    320   // Push the this ptr.
    321   Args.add(RValue::get(This), ThisType);
    322 
    323   // And the rest of the call args
    324   EmitCallArgs(Args, FPT, E->arg_begin(), E->arg_end());
    325   return EmitCall(CGM.getTypes().arrangeFunctionCall(Args, FPT), Callee,
    326                   ReturnValue, Args);
    327 }
    328 
    329 RValue
    330 CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
    331                                                const CXXMethodDecl *MD,
    332                                                ReturnValueSlot ReturnValue) {
    333   assert(MD->isInstance() &&
    334          "Trying to emit a member call expr on a static method!");
    335   LValue LV = EmitLValue(E->getArg(0));
    336   llvm::Value *This = LV.getAddress();
    337 
    338   if ((MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) &&
    339       MD->isTrivial()) {
    340     llvm::Value *Src = EmitLValue(E->getArg(1)).getAddress();
    341     QualType Ty = E->getType();
    342     EmitAggregateCopy(This, Src, Ty);
    343     return RValue::get(This);
    344   }
    345 
    346   llvm::Value *Callee = EmitCXXOperatorMemberCallee(E, MD, This);
    347   return EmitCXXMemberCall(MD, Callee, ReturnValue, This, /*VTT=*/0,
    348                            E->arg_begin() + 1, E->arg_end());
    349 }
    350 
    351 RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E,
    352                                                ReturnValueSlot ReturnValue) {
    353   return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue);
    354 }
    355 
    356 static void EmitNullBaseClassInitialization(CodeGenFunction &CGF,
    357                                             llvm::Value *DestPtr,
    358                                             const CXXRecordDecl *Base) {
    359   if (Base->isEmpty())
    360     return;
    361 
    362   DestPtr = CGF.EmitCastToVoidPtr(DestPtr);
    363 
    364   const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base);
    365   CharUnits Size = Layout.getNonVirtualSize();
    366   CharUnits Align = Layout.getNonVirtualAlign();
    367 
    368   llvm::Value *SizeVal = CGF.CGM.getSize(Size);
    369 
    370   // If the type contains a pointer to data member we can't memset it to zero.
    371   // Instead, create a null constant and copy it to the destination.
    372   // TODO: there are other patterns besides zero that we can usefully memset,
    373   // like -1, which happens to be the pattern used by member-pointers.
    374   // TODO: isZeroInitializable can be over-conservative in the case where a
    375   // virtual base contains a member pointer.
    376   if (!CGF.CGM.getTypes().isZeroInitializable(Base)) {
    377     llvm::Constant *NullConstant = CGF.CGM.EmitNullConstantForBase(Base);
    378 
    379     llvm::GlobalVariable *NullVariable =
    380       new llvm::GlobalVariable(CGF.CGM.getModule(), NullConstant->getType(),
    381                                /*isConstant=*/true,
    382                                llvm::GlobalVariable::PrivateLinkage,
    383                                NullConstant, Twine());
    384     NullVariable->setAlignment(Align.getQuantity());
    385     llvm::Value *SrcPtr = CGF.EmitCastToVoidPtr(NullVariable);
    386 
    387     // Get and call the appropriate llvm.memcpy overload.
    388     CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity());
    389     return;
    390   }
    391 
    392   // Otherwise, just memset the whole thing to zero.  This is legal
    393   // because in LLVM, all default initializers (other than the ones we just
    394   // handled above) are guaranteed to have a bit pattern of all zeros.
    395   CGF.Builder.CreateMemSet(DestPtr, CGF.Builder.getInt8(0), SizeVal,
    396                            Align.getQuantity());
    397 }
    398 
    399 void
    400 CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E,
    401                                       AggValueSlot Dest) {
    402   assert(!Dest.isIgnored() && "Must have a destination!");
    403   const CXXConstructorDecl *CD = E->getConstructor();
    404 
    405   // If we require zero initialization before (or instead of) calling the
    406   // constructor, as can be the case with a non-user-provided default
    407   // constructor, emit the zero initialization now, unless destination is
    408   // already zeroed.
    409   if (E->requiresZeroInitialization() && !Dest.isZeroed()) {
    410     switch (E->getConstructionKind()) {
    411     case CXXConstructExpr::CK_Delegating:
    412       assert(0 && "Delegating constructor should not need zeroing");
    413     case CXXConstructExpr::CK_Complete:
    414       EmitNullInitialization(Dest.getAddr(), E->getType());
    415       break;
    416     case CXXConstructExpr::CK_VirtualBase:
    417     case CXXConstructExpr::CK_NonVirtualBase:
    418       EmitNullBaseClassInitialization(*this, Dest.getAddr(), CD->getParent());
    419       break;
    420     }
    421   }
    422 
    423   // If this is a call to a trivial default constructor, do nothing.
    424   if (CD->isTrivial() && CD->isDefaultConstructor())
    425     return;
    426 
    427   // Elide the constructor if we're constructing from a temporary.
    428   // The temporary check is required because Sema sets this on NRVO
    429   // returns.
    430   if (getContext().getLangOpts().ElideConstructors && E->isElidable()) {
    431     assert(getContext().hasSameUnqualifiedType(E->getType(),
    432                                                E->getArg(0)->getType()));
    433     if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) {
    434       EmitAggExpr(E->getArg(0), Dest);
    435       return;
    436     }
    437   }
    438 
    439   if (const ConstantArrayType *arrayType
    440         = getContext().getAsConstantArrayType(E->getType())) {
    441     EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddr(),
    442                                E->arg_begin(), E->arg_end());
    443   } else {
    444     CXXCtorType Type = Ctor_Complete;
    445     bool ForVirtualBase = false;
    446 
    447     switch (E->getConstructionKind()) {
    448      case CXXConstructExpr::CK_Delegating:
    449       // We should be emitting a constructor; GlobalDecl will assert this
    450       Type = CurGD.getCtorType();
    451       break;
    452 
    453      case CXXConstructExpr::CK_Complete:
    454       Type = Ctor_Complete;
    455       break;
    456 
    457      case CXXConstructExpr::CK_VirtualBase:
    458       ForVirtualBase = true;
    459       // fall-through
    460 
    461      case CXXConstructExpr::CK_NonVirtualBase:
    462       Type = Ctor_Base;
    463     }
    464 
    465     // Call the constructor.
    466     EmitCXXConstructorCall(CD, Type, ForVirtualBase, Dest.getAddr(),
    467                            E->arg_begin(), E->arg_end());
    468   }
    469 }
    470 
    471 void
    472 CodeGenFunction::EmitSynthesizedCXXCopyCtor(llvm::Value *Dest,
    473                                             llvm::Value *Src,
    474                                             const Expr *Exp) {
    475   if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp))
    476     Exp = E->getSubExpr();
    477   assert(isa<CXXConstructExpr>(Exp) &&
    478          "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr");
    479   const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp);
    480   const CXXConstructorDecl *CD = E->getConstructor();
    481   RunCleanupsScope Scope(*this);
    482 
    483   // If we require zero initialization before (or instead of) calling the
    484   // constructor, as can be the case with a non-user-provided default
    485   // constructor, emit the zero initialization now.
    486   // FIXME. Do I still need this for a copy ctor synthesis?
    487   if (E->requiresZeroInitialization())
    488     EmitNullInitialization(Dest, E->getType());
    489 
    490   assert(!getContext().getAsConstantArrayType(E->getType())
    491          && "EmitSynthesizedCXXCopyCtor - Copied-in Array");
    492   EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src,
    493                                  E->arg_begin(), E->arg_end());
    494 }
    495 
    496 static CharUnits CalculateCookiePadding(CodeGenFunction &CGF,
    497                                         const CXXNewExpr *E) {
    498   if (!E->isArray())
    499     return CharUnits::Zero();
    500 
    501   // No cookie is required if the operator new[] being used is the
    502   // reserved placement operator new[].
    503   if (E->getOperatorNew()->isReservedGlobalPlacementOperator())
    504     return CharUnits::Zero();
    505 
    506   return CGF.CGM.getCXXABI().GetArrayCookieSize(E);
    507 }
    508 
    509 static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF,
    510                                         const CXXNewExpr *e,
    511                                         unsigned minElements,
    512                                         llvm::Value *&numElements,
    513                                         llvm::Value *&sizeWithoutCookie) {
    514   QualType type = e->getAllocatedType();
    515 
    516   if (!e->isArray()) {
    517     CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
    518     sizeWithoutCookie
    519       = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity());
    520     return sizeWithoutCookie;
    521   }
    522 
    523   // The width of size_t.
    524   unsigned sizeWidth = CGF.SizeTy->getBitWidth();
    525 
    526   // Figure out the cookie size.
    527   llvm::APInt cookieSize(sizeWidth,
    528                          CalculateCookiePadding(CGF, e).getQuantity());
    529 
    530   // Emit the array size expression.
    531   // We multiply the size of all dimensions for NumElements.
    532   // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6.
    533   numElements = CGF.EmitScalarExpr(e->getArraySize());
    534   assert(isa<llvm::IntegerType>(numElements->getType()));
    535 
    536   // The number of elements can be have an arbitrary integer type;
    537   // essentially, we need to multiply it by a constant factor, add a
    538   // cookie size, and verify that the result is representable as a
    539   // size_t.  That's just a gloss, though, and it's wrong in one
    540   // important way: if the count is negative, it's an error even if
    541   // the cookie size would bring the total size >= 0.
    542   bool isSigned
    543     = e->getArraySize()->getType()->isSignedIntegerOrEnumerationType();
    544   llvm::IntegerType *numElementsType
    545     = cast<llvm::IntegerType>(numElements->getType());
    546   unsigned numElementsWidth = numElementsType->getBitWidth();
    547 
    548   // Compute the constant factor.
    549   llvm::APInt arraySizeMultiplier(sizeWidth, 1);
    550   while (const ConstantArrayType *CAT
    551              = CGF.getContext().getAsConstantArrayType(type)) {
    552     type = CAT->getElementType();
    553     arraySizeMultiplier *= CAT->getSize();
    554   }
    555 
    556   CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
    557   llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity());
    558   typeSizeMultiplier *= arraySizeMultiplier;
    559 
    560   // This will be a size_t.
    561   llvm::Value *size;
    562 
    563   // If someone is doing 'new int[42]' there is no need to do a dynamic check.
    564   // Don't bloat the -O0 code.
    565   if (llvm::ConstantInt *numElementsC =
    566         dyn_cast<llvm::ConstantInt>(numElements)) {
    567     const llvm::APInt &count = numElementsC->getValue();
    568 
    569     bool hasAnyOverflow = false;
    570 
    571     // If 'count' was a negative number, it's an overflow.
    572     if (isSigned && count.isNegative())
    573       hasAnyOverflow = true;
    574 
    575     // We want to do all this arithmetic in size_t.  If numElements is
    576     // wider than that, check whether it's already too big, and if so,
    577     // overflow.
    578     else if (numElementsWidth > sizeWidth &&
    579              numElementsWidth - sizeWidth > count.countLeadingZeros())
    580       hasAnyOverflow = true;
    581 
    582     // Okay, compute a count at the right width.
    583     llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth);
    584 
    585     // If there is a brace-initializer, we cannot allocate fewer elements than
    586     // there are initializers. If we do, that's treated like an overflow.
    587     if (adjustedCount.ult(minElements))
    588       hasAnyOverflow = true;
    589 
    590     // Scale numElements by that.  This might overflow, but we don't
    591     // care because it only overflows if allocationSize does, too, and
    592     // if that overflows then we shouldn't use this.
    593     numElements = llvm::ConstantInt::get(CGF.SizeTy,
    594                                          adjustedCount * arraySizeMultiplier);
    595 
    596     // Compute the size before cookie, and track whether it overflowed.
    597     bool overflow;
    598     llvm::APInt allocationSize
    599       = adjustedCount.umul_ov(typeSizeMultiplier, overflow);
    600     hasAnyOverflow |= overflow;
    601 
    602     // Add in the cookie, and check whether it's overflowed.
    603     if (cookieSize != 0) {
    604       // Save the current size without a cookie.  This shouldn't be
    605       // used if there was overflow.
    606       sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
    607 
    608       allocationSize = allocationSize.uadd_ov(cookieSize, overflow);
    609       hasAnyOverflow |= overflow;
    610     }
    611 
    612     // On overflow, produce a -1 so operator new will fail.
    613     if (hasAnyOverflow) {
    614       size = llvm::Constant::getAllOnesValue(CGF.SizeTy);
    615     } else {
    616       size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
    617     }
    618 
    619   // Otherwise, we might need to use the overflow intrinsics.
    620   } else {
    621     // There are up to five conditions we need to test for:
    622     // 1) if isSigned, we need to check whether numElements is negative;
    623     // 2) if numElementsWidth > sizeWidth, we need to check whether
    624     //   numElements is larger than something representable in size_t;
    625     // 3) if minElements > 0, we need to check whether numElements is smaller
    626     //    than that.
    627     // 4) we need to compute
    628     //      sizeWithoutCookie := numElements * typeSizeMultiplier
    629     //    and check whether it overflows; and
    630     // 5) if we need a cookie, we need to compute
    631     //      size := sizeWithoutCookie + cookieSize
    632     //    and check whether it overflows.
    633 
    634     llvm::Value *hasOverflow = 0;
    635 
    636     // If numElementsWidth > sizeWidth, then one way or another, we're
    637     // going to have to do a comparison for (2), and this happens to
    638     // take care of (1), too.
    639     if (numElementsWidth > sizeWidth) {
    640       llvm::APInt threshold(numElementsWidth, 1);
    641       threshold <<= sizeWidth;
    642 
    643       llvm::Value *thresholdV
    644         = llvm::ConstantInt::get(numElementsType, threshold);
    645 
    646       hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV);
    647       numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy);
    648 
    649     // Otherwise, if we're signed, we want to sext up to size_t.
    650     } else if (isSigned) {
    651       if (numElementsWidth < sizeWidth)
    652         numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy);
    653 
    654       // If there's a non-1 type size multiplier, then we can do the
    655       // signedness check at the same time as we do the multiply
    656       // because a negative number times anything will cause an
    657       // unsigned overflow.  Otherwise, we have to do it here. But at least
    658       // in this case, we can subsume the >= minElements check.
    659       if (typeSizeMultiplier == 1)
    660         hasOverflow = CGF.Builder.CreateICmpSLT(numElements,
    661                               llvm::ConstantInt::get(CGF.SizeTy, minElements));
    662 
    663     // Otherwise, zext up to size_t if necessary.
    664     } else if (numElementsWidth < sizeWidth) {
    665       numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy);
    666     }
    667 
    668     assert(numElements->getType() == CGF.SizeTy);
    669 
    670     if (minElements) {
    671       // Don't allow allocation of fewer elements than we have initializers.
    672       if (!hasOverflow) {
    673         hasOverflow = CGF.Builder.CreateICmpULT(numElements,
    674                               llvm::ConstantInt::get(CGF.SizeTy, minElements));
    675       } else if (numElementsWidth > sizeWidth) {
    676         // The other existing overflow subsumes this check.
    677         // We do an unsigned comparison, since any signed value < -1 is
    678         // taken care of either above or below.
    679         hasOverflow = CGF.Builder.CreateOr(hasOverflow,
    680                           CGF.Builder.CreateICmpULT(numElements,
    681                               llvm::ConstantInt::get(CGF.SizeTy, minElements)));
    682       }
    683     }
    684 
    685     size = numElements;
    686 
    687     // Multiply by the type size if necessary.  This multiplier
    688     // includes all the factors for nested arrays.
    689     //
    690     // This step also causes numElements to be scaled up by the
    691     // nested-array factor if necessary.  Overflow on this computation
    692     // can be ignored because the result shouldn't be used if
    693     // allocation fails.
    694     if (typeSizeMultiplier != 1) {
    695       llvm::Value *umul_with_overflow
    696         = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy);
    697 
    698       llvm::Value *tsmV =
    699         llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier);
    700       llvm::Value *result =
    701         CGF.Builder.CreateCall2(umul_with_overflow, size, tsmV);
    702 
    703       llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
    704       if (hasOverflow)
    705         hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
    706       else
    707         hasOverflow = overflowed;
    708 
    709       size = CGF.Builder.CreateExtractValue(result, 0);
    710 
    711       // Also scale up numElements by the array size multiplier.
    712       if (arraySizeMultiplier != 1) {
    713         // If the base element type size is 1, then we can re-use the
    714         // multiply we just did.
    715         if (typeSize.isOne()) {
    716           assert(arraySizeMultiplier == typeSizeMultiplier);
    717           numElements = size;
    718 
    719         // Otherwise we need a separate multiply.
    720         } else {
    721           llvm::Value *asmV =
    722             llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier);
    723           numElements = CGF.Builder.CreateMul(numElements, asmV);
    724         }
    725       }
    726     } else {
    727       // numElements doesn't need to be scaled.
    728       assert(arraySizeMultiplier == 1);
    729     }
    730 
    731     // Add in the cookie size if necessary.
    732     if (cookieSize != 0) {
    733       sizeWithoutCookie = size;
    734 
    735       llvm::Value *uadd_with_overflow
    736         = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy);
    737 
    738       llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize);
    739       llvm::Value *result =
    740         CGF.Builder.CreateCall2(uadd_with_overflow, size, cookieSizeV);
    741 
    742       llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
    743       if (hasOverflow)
    744         hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
    745       else
    746         hasOverflow = overflowed;
    747 
    748       size = CGF.Builder.CreateExtractValue(result, 0);
    749     }
    750 
    751     // If we had any possibility of dynamic overflow, make a select to
    752     // overwrite 'size' with an all-ones value, which should cause
    753     // operator new to throw.
    754     if (hasOverflow)
    755       size = CGF.Builder.CreateSelect(hasOverflow,
    756                                  llvm::Constant::getAllOnesValue(CGF.SizeTy),
    757                                       size);
    758   }
    759 
    760   if (cookieSize == 0)
    761     sizeWithoutCookie = size;
    762   else
    763     assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?");
    764 
    765   return size;
    766 }
    767 
    768 static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init,
    769                                     QualType AllocType, llvm::Value *NewPtr) {
    770 
    771   CharUnits Alignment = CGF.getContext().getTypeAlignInChars(AllocType);
    772   if (!CGF.hasAggregateLLVMType(AllocType))
    773     CGF.EmitScalarInit(Init, 0, CGF.MakeAddrLValue(NewPtr, AllocType,
    774                                                    Alignment),
    775                        false);
    776   else if (AllocType->isAnyComplexType())
    777     CGF.EmitComplexExprIntoAddr(Init, NewPtr,
    778                                 AllocType.isVolatileQualified());
    779   else {
    780     AggValueSlot Slot
    781       = AggValueSlot::forAddr(NewPtr, Alignment, AllocType.getQualifiers(),
    782                               AggValueSlot::IsDestructed,
    783                               AggValueSlot::DoesNotNeedGCBarriers,
    784                               AggValueSlot::IsNotAliased);
    785     CGF.EmitAggExpr(Init, Slot);
    786 
    787     CGF.MaybeEmitStdInitializerListCleanup(NewPtr, Init);
    788   }
    789 }
    790 
    791 void
    792 CodeGenFunction::EmitNewArrayInitializer(const CXXNewExpr *E,
    793                                          QualType elementType,
    794                                          llvm::Value *beginPtr,
    795                                          llvm::Value *numElements) {
    796   if (!E->hasInitializer())
    797     return; // We have a POD type.
    798 
    799   llvm::Value *explicitPtr = beginPtr;
    800   // Find the end of the array, hoisted out of the loop.
    801   llvm::Value *endPtr =
    802     Builder.CreateInBoundsGEP(beginPtr, numElements, "array.end");
    803 
    804   unsigned initializerElements = 0;
    805 
    806   const Expr *Init = E->getInitializer();
    807   llvm::AllocaInst *endOfInit = 0;
    808   QualType::DestructionKind dtorKind = elementType.isDestructedType();
    809   EHScopeStack::stable_iterator cleanup;
    810   llvm::Instruction *cleanupDominator = 0;
    811   // If the initializer is an initializer list, first do the explicit elements.
    812   if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
    813     initializerElements = ILE->getNumInits();
    814 
    815     // Enter a partial-destruction cleanup if necessary.
    816     if (needsEHCleanup(dtorKind)) {
    817       // In principle we could tell the cleanup where we are more
    818       // directly, but the control flow can get so varied here that it
    819       // would actually be quite complex.  Therefore we go through an
    820       // alloca.
    821       endOfInit = CreateTempAlloca(beginPtr->getType(), "array.endOfInit");
    822       cleanupDominator = Builder.CreateStore(beginPtr, endOfInit);
    823       pushIrregularPartialArrayCleanup(beginPtr, endOfInit, elementType,
    824                                        getDestroyer(dtorKind));
    825       cleanup = EHStack.stable_begin();
    826     }
    827 
    828     for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) {
    829       // Tell the cleanup that it needs to destroy up to this
    830       // element.  TODO: some of these stores can be trivially
    831       // observed to be unnecessary.
    832       if (endOfInit) Builder.CreateStore(explicitPtr, endOfInit);
    833       StoreAnyExprIntoOneUnit(*this, ILE->getInit(i), elementType, explicitPtr);
    834       explicitPtr =Builder.CreateConstGEP1_32(explicitPtr, 1, "array.exp.next");
    835     }
    836 
    837     // The remaining elements are filled with the array filler expression.
    838     Init = ILE->getArrayFiller();
    839   }
    840 
    841   // Create the continuation block.
    842   llvm::BasicBlock *contBB = createBasicBlock("new.loop.end");
    843 
    844   // If the number of elements isn't constant, we have to now check if there is
    845   // anything left to initialize.
    846   if (llvm::ConstantInt *constNum = dyn_cast<llvm::ConstantInt>(numElements)) {
    847     // If all elements have already been initialized, skip the whole loop.
    848     if (constNum->getZExtValue() <= initializerElements) {
    849       // If there was a cleanup, deactivate it.
    850       if (cleanupDominator)
    851         DeactivateCleanupBlock(cleanup, cleanupDominator);;
    852       return;
    853     }
    854   } else {
    855     llvm::BasicBlock *nonEmptyBB = createBasicBlock("new.loop.nonempty");
    856     llvm::Value *isEmpty = Builder.CreateICmpEQ(explicitPtr, endPtr,
    857                                                 "array.isempty");
    858     Builder.CreateCondBr(isEmpty, contBB, nonEmptyBB);
    859     EmitBlock(nonEmptyBB);
    860   }
    861 
    862   // Enter the loop.
    863   llvm::BasicBlock *entryBB = Builder.GetInsertBlock();
    864   llvm::BasicBlock *loopBB = createBasicBlock("new.loop");
    865 
    866   EmitBlock(loopBB);
    867 
    868   // Set up the current-element phi.
    869   llvm::PHINode *curPtr =
    870     Builder.CreatePHI(explicitPtr->getType(), 2, "array.cur");
    871   curPtr->addIncoming(explicitPtr, entryBB);
    872 
    873   // Store the new cleanup position for irregular cleanups.
    874   if (endOfInit) Builder.CreateStore(curPtr, endOfInit);
    875 
    876   // Enter a partial-destruction cleanup if necessary.
    877   if (!cleanupDominator && needsEHCleanup(dtorKind)) {
    878     pushRegularPartialArrayCleanup(beginPtr, curPtr, elementType,
    879                                    getDestroyer(dtorKind));
    880     cleanup = EHStack.stable_begin();
    881     cleanupDominator = Builder.CreateUnreachable();
    882   }
    883 
    884   // Emit the initializer into this element.
    885   StoreAnyExprIntoOneUnit(*this, Init, E->getAllocatedType(), curPtr);
    886 
    887   // Leave the cleanup if we entered one.
    888   if (cleanupDominator) {
    889     DeactivateCleanupBlock(cleanup, cleanupDominator);
    890     cleanupDominator->eraseFromParent();
    891   }
    892 
    893   // Advance to the next element.
    894   llvm::Value *nextPtr = Builder.CreateConstGEP1_32(curPtr, 1, "array.next");
    895 
    896   // Check whether we've gotten to the end of the array and, if so,
    897   // exit the loop.
    898   llvm::Value *isEnd = Builder.CreateICmpEQ(nextPtr, endPtr, "array.atend");
    899   Builder.CreateCondBr(isEnd, contBB, loopBB);
    900   curPtr->addIncoming(nextPtr, Builder.GetInsertBlock());
    901 
    902   EmitBlock(contBB);
    903 }
    904 
    905 static void EmitZeroMemSet(CodeGenFunction &CGF, QualType T,
    906                            llvm::Value *NewPtr, llvm::Value *Size) {
    907   CGF.EmitCastToVoidPtr(NewPtr);
    908   CharUnits Alignment = CGF.getContext().getTypeAlignInChars(T);
    909   CGF.Builder.CreateMemSet(NewPtr, CGF.Builder.getInt8(0), Size,
    910                            Alignment.getQuantity(), false);
    911 }
    912 
    913 static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E,
    914                                QualType ElementType,
    915                                llvm::Value *NewPtr,
    916                                llvm::Value *NumElements,
    917                                llvm::Value *AllocSizeWithoutCookie) {
    918   const Expr *Init = E->getInitializer();
    919   if (E->isArray()) {
    920     if (const CXXConstructExpr *CCE = dyn_cast_or_null<CXXConstructExpr>(Init)){
    921       CXXConstructorDecl *Ctor = CCE->getConstructor();
    922       bool RequiresZeroInitialization = false;
    923       if (Ctor->isTrivial()) {
    924         // If new expression did not specify value-initialization, then there
    925         // is no initialization.
    926         if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty())
    927           return;
    928 
    929         if (CGF.CGM.getTypes().isZeroInitializable(ElementType)) {
    930           // Optimization: since zero initialization will just set the memory
    931           // to all zeroes, generate a single memset to do it in one shot.
    932           EmitZeroMemSet(CGF, ElementType, NewPtr, AllocSizeWithoutCookie);
    933           return;
    934         }
    935 
    936         RequiresZeroInitialization = true;
    937       }
    938 
    939       CGF.EmitCXXAggrConstructorCall(Ctor, NumElements, NewPtr,
    940                                      CCE->arg_begin(),  CCE->arg_end(),
    941                                      RequiresZeroInitialization);
    942       return;
    943     } else if (Init && isa<ImplicitValueInitExpr>(Init) &&
    944                CGF.CGM.getTypes().isZeroInitializable(ElementType)) {
    945       // Optimization: since zero initialization will just set the memory
    946       // to all zeroes, generate a single memset to do it in one shot.
    947       EmitZeroMemSet(CGF, ElementType, NewPtr, AllocSizeWithoutCookie);
    948       return;
    949     }
    950     CGF.EmitNewArrayInitializer(E, ElementType, NewPtr, NumElements);
    951     return;
    952   }
    953 
    954   if (!Init)
    955     return;
    956 
    957   StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr);
    958 }
    959 
    960 namespace {
    961   /// A cleanup to call the given 'operator delete' function upon
    962   /// abnormal exit from a new expression.
    963   class CallDeleteDuringNew : public EHScopeStack::Cleanup {
    964     size_t NumPlacementArgs;
    965     const FunctionDecl *OperatorDelete;
    966     llvm::Value *Ptr;
    967     llvm::Value *AllocSize;
    968 
    969     RValue *getPlacementArgs() { return reinterpret_cast<RValue*>(this+1); }
    970 
    971   public:
    972     static size_t getExtraSize(size_t NumPlacementArgs) {
    973       return NumPlacementArgs * sizeof(RValue);
    974     }
    975 
    976     CallDeleteDuringNew(size_t NumPlacementArgs,
    977                         const FunctionDecl *OperatorDelete,
    978                         llvm::Value *Ptr,
    979                         llvm::Value *AllocSize)
    980       : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete),
    981         Ptr(Ptr), AllocSize(AllocSize) {}
    982 
    983     void setPlacementArg(unsigned I, RValue Arg) {
    984       assert(I < NumPlacementArgs && "index out of range");
    985       getPlacementArgs()[I] = Arg;
    986     }
    987 
    988     void Emit(CodeGenFunction &CGF, Flags flags) {
    989       const FunctionProtoType *FPT
    990         = OperatorDelete->getType()->getAs<FunctionProtoType>();
    991       assert(FPT->getNumArgs() == NumPlacementArgs + 1 ||
    992              (FPT->getNumArgs() == 2 && NumPlacementArgs == 0));
    993 
    994       CallArgList DeleteArgs;
    995 
    996       // The first argument is always a void*.
    997       FunctionProtoType::arg_type_iterator AI = FPT->arg_type_begin();
    998       DeleteArgs.add(RValue::get(Ptr), *AI++);
    999 
   1000       // A member 'operator delete' can take an extra 'size_t' argument.
   1001       if (FPT->getNumArgs() == NumPlacementArgs + 2)
   1002         DeleteArgs.add(RValue::get(AllocSize), *AI++);
   1003 
   1004       // Pass the rest of the arguments, which must match exactly.
   1005       for (unsigned I = 0; I != NumPlacementArgs; ++I)
   1006         DeleteArgs.add(getPlacementArgs()[I], *AI++);
   1007 
   1008       // Call 'operator delete'.
   1009       CGF.EmitCall(CGF.CGM.getTypes().arrangeFunctionCall(DeleteArgs, FPT),
   1010                    CGF.CGM.GetAddrOfFunction(OperatorDelete),
   1011                    ReturnValueSlot(), DeleteArgs, OperatorDelete);
   1012     }
   1013   };
   1014 
   1015   /// A cleanup to call the given 'operator delete' function upon
   1016   /// abnormal exit from a new expression when the new expression is
   1017   /// conditional.
   1018   class CallDeleteDuringConditionalNew : public EHScopeStack::Cleanup {
   1019     size_t NumPlacementArgs;
   1020     const FunctionDecl *OperatorDelete;
   1021     DominatingValue<RValue>::saved_type Ptr;
   1022     DominatingValue<RValue>::saved_type AllocSize;
   1023 
   1024     DominatingValue<RValue>::saved_type *getPlacementArgs() {
   1025       return reinterpret_cast<DominatingValue<RValue>::saved_type*>(this+1);
   1026     }
   1027 
   1028   public:
   1029     static size_t getExtraSize(size_t NumPlacementArgs) {
   1030       return NumPlacementArgs * sizeof(DominatingValue<RValue>::saved_type);
   1031     }
   1032 
   1033     CallDeleteDuringConditionalNew(size_t NumPlacementArgs,
   1034                                    const FunctionDecl *OperatorDelete,
   1035                                    DominatingValue<RValue>::saved_type Ptr,
   1036                               DominatingValue<RValue>::saved_type AllocSize)
   1037       : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete),
   1038         Ptr(Ptr), AllocSize(AllocSize) {}
   1039 
   1040     void setPlacementArg(unsigned I, DominatingValue<RValue>::saved_type Arg) {
   1041       assert(I < NumPlacementArgs && "index out of range");
   1042       getPlacementArgs()[I] = Arg;
   1043     }
   1044 
   1045     void Emit(CodeGenFunction &CGF, Flags flags) {
   1046       const FunctionProtoType *FPT
   1047         = OperatorDelete->getType()->getAs<FunctionProtoType>();
   1048       assert(FPT->getNumArgs() == NumPlacementArgs + 1 ||
   1049              (FPT->getNumArgs() == 2 && NumPlacementArgs == 0));
   1050 
   1051       CallArgList DeleteArgs;
   1052 
   1053       // The first argument is always a void*.
   1054       FunctionProtoType::arg_type_iterator AI = FPT->arg_type_begin();
   1055       DeleteArgs.add(Ptr.restore(CGF), *AI++);
   1056 
   1057       // A member 'operator delete' can take an extra 'size_t' argument.
   1058       if (FPT->getNumArgs() == NumPlacementArgs + 2) {
   1059         RValue RV = AllocSize.restore(CGF);
   1060         DeleteArgs.add(RV, *AI++);
   1061       }
   1062 
   1063       // Pass the rest of the arguments, which must match exactly.
   1064       for (unsigned I = 0; I != NumPlacementArgs; ++I) {
   1065         RValue RV = getPlacementArgs()[I].restore(CGF);
   1066         DeleteArgs.add(RV, *AI++);
   1067       }
   1068 
   1069       // Call 'operator delete'.
   1070       CGF.EmitCall(CGF.CGM.getTypes().arrangeFunctionCall(DeleteArgs, FPT),
   1071                    CGF.CGM.GetAddrOfFunction(OperatorDelete),
   1072                    ReturnValueSlot(), DeleteArgs, OperatorDelete);
   1073     }
   1074   };
   1075 }
   1076 
   1077 /// Enter a cleanup to call 'operator delete' if the initializer in a
   1078 /// new-expression throws.
   1079 static void EnterNewDeleteCleanup(CodeGenFunction &CGF,
   1080                                   const CXXNewExpr *E,
   1081                                   llvm::Value *NewPtr,
   1082                                   llvm::Value *AllocSize,
   1083                                   const CallArgList &NewArgs) {
   1084   // If we're not inside a conditional branch, then the cleanup will
   1085   // dominate and we can do the easier (and more efficient) thing.
   1086   if (!CGF.isInConditionalBranch()) {
   1087     CallDeleteDuringNew *Cleanup = CGF.EHStack
   1088       .pushCleanupWithExtra<CallDeleteDuringNew>(EHCleanup,
   1089                                                  E->getNumPlacementArgs(),
   1090                                                  E->getOperatorDelete(),
   1091                                                  NewPtr, AllocSize);
   1092     for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I)
   1093       Cleanup->setPlacementArg(I, NewArgs[I+1].RV);
   1094 
   1095     return;
   1096   }
   1097 
   1098   // Otherwise, we need to save all this stuff.
   1099   DominatingValue<RValue>::saved_type SavedNewPtr =
   1100     DominatingValue<RValue>::save(CGF, RValue::get(NewPtr));
   1101   DominatingValue<RValue>::saved_type SavedAllocSize =
   1102     DominatingValue<RValue>::save(CGF, RValue::get(AllocSize));
   1103 
   1104   CallDeleteDuringConditionalNew *Cleanup = CGF.EHStack
   1105     .pushCleanupWithExtra<CallDeleteDuringConditionalNew>(EHCleanup,
   1106                                                  E->getNumPlacementArgs(),
   1107                                                  E->getOperatorDelete(),
   1108                                                  SavedNewPtr,
   1109                                                  SavedAllocSize);
   1110   for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I)
   1111     Cleanup->setPlacementArg(I,
   1112                      DominatingValue<RValue>::save(CGF, NewArgs[I+1].RV));
   1113 
   1114   CGF.initFullExprCleanup();
   1115 }
   1116 
   1117 llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) {
   1118   // The element type being allocated.
   1119   QualType allocType = getContext().getBaseElementType(E->getAllocatedType());
   1120 
   1121   // 1. Build a call to the allocation function.
   1122   FunctionDecl *allocator = E->getOperatorNew();
   1123   const FunctionProtoType *allocatorType =
   1124     allocator->getType()->castAs<FunctionProtoType>();
   1125 
   1126   CallArgList allocatorArgs;
   1127 
   1128   // The allocation size is the first argument.
   1129   QualType sizeType = getContext().getSizeType();
   1130 
   1131   // If there is a brace-initializer, cannot allocate fewer elements than inits.
   1132   unsigned minElements = 0;
   1133   if (E->isArray() && E->hasInitializer()) {
   1134     if (const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer()))
   1135       minElements = ILE->getNumInits();
   1136   }
   1137 
   1138   llvm::Value *numElements = 0;
   1139   llvm::Value *allocSizeWithoutCookie = 0;
   1140   llvm::Value *allocSize =
   1141     EmitCXXNewAllocSize(*this, E, minElements, numElements,
   1142                         allocSizeWithoutCookie);
   1143 
   1144   allocatorArgs.add(RValue::get(allocSize), sizeType);
   1145 
   1146   // Emit the rest of the arguments.
   1147   // FIXME: Ideally, this should just use EmitCallArgs.
   1148   CXXNewExpr::const_arg_iterator placementArg = E->placement_arg_begin();
   1149 
   1150   // First, use the types from the function type.
   1151   // We start at 1 here because the first argument (the allocation size)
   1152   // has already been emitted.
   1153   for (unsigned i = 1, e = allocatorType->getNumArgs(); i != e;
   1154        ++i, ++placementArg) {
   1155     QualType argType = allocatorType->getArgType(i);
   1156 
   1157     assert(getContext().hasSameUnqualifiedType(argType.getNonReferenceType(),
   1158                                                placementArg->getType()) &&
   1159            "type mismatch in call argument!");
   1160 
   1161     EmitCallArg(allocatorArgs, *placementArg, argType);
   1162   }
   1163 
   1164   // Either we've emitted all the call args, or we have a call to a
   1165   // variadic function.
   1166   assert((placementArg == E->placement_arg_end() ||
   1167           allocatorType->isVariadic()) &&
   1168          "Extra arguments to non-variadic function!");
   1169 
   1170   // If we still have any arguments, emit them using the type of the argument.
   1171   for (CXXNewExpr::const_arg_iterator placementArgsEnd = E->placement_arg_end();
   1172        placementArg != placementArgsEnd; ++placementArg) {
   1173     EmitCallArg(allocatorArgs, *placementArg, placementArg->getType());
   1174   }
   1175 
   1176   // Emit the allocation call.  If the allocator is a global placement
   1177   // operator, just "inline" it directly.
   1178   RValue RV;
   1179   if (allocator->isReservedGlobalPlacementOperator()) {
   1180     assert(allocatorArgs.size() == 2);
   1181     RV = allocatorArgs[1].RV;
   1182     // TODO: kill any unnecessary computations done for the size
   1183     // argument.
   1184   } else {
   1185     RV = EmitCall(CGM.getTypes().arrangeFunctionCall(allocatorArgs,
   1186                                                      allocatorType),
   1187                   CGM.GetAddrOfFunction(allocator), ReturnValueSlot(),
   1188                   allocatorArgs, allocator);
   1189   }
   1190 
   1191   // Emit a null check on the allocation result if the allocation
   1192   // function is allowed to return null (because it has a non-throwing
   1193   // exception spec; for this part, we inline
   1194   // CXXNewExpr::shouldNullCheckAllocation()) and we have an
   1195   // interesting initializer.
   1196   bool nullCheck = allocatorType->isNothrow(getContext()) &&
   1197     (!allocType.isPODType(getContext()) || E->hasInitializer());
   1198 
   1199   llvm::BasicBlock *nullCheckBB = 0;
   1200   llvm::BasicBlock *contBB = 0;
   1201 
   1202   llvm::Value *allocation = RV.getScalarVal();
   1203   unsigned AS =
   1204     cast<llvm::PointerType>(allocation->getType())->getAddressSpace();
   1205 
   1206   // The null-check means that the initializer is conditionally
   1207   // evaluated.
   1208   ConditionalEvaluation conditional(*this);
   1209 
   1210   if (nullCheck) {
   1211     conditional.begin(*this);
   1212 
   1213     nullCheckBB = Builder.GetInsertBlock();
   1214     llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull");
   1215     contBB = createBasicBlock("new.cont");
   1216 
   1217     llvm::Value *isNull = Builder.CreateIsNull(allocation, "new.isnull");
   1218     Builder.CreateCondBr(isNull, contBB, notNullBB);
   1219     EmitBlock(notNullBB);
   1220   }
   1221 
   1222   // If there's an operator delete, enter a cleanup to call it if an
   1223   // exception is thrown.
   1224   EHScopeStack::stable_iterator operatorDeleteCleanup;
   1225   llvm::Instruction *cleanupDominator = 0;
   1226   if (E->getOperatorDelete() &&
   1227       !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
   1228     EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocatorArgs);
   1229     operatorDeleteCleanup = EHStack.stable_begin();
   1230     cleanupDominator = Builder.CreateUnreachable();
   1231   }
   1232 
   1233   assert((allocSize == allocSizeWithoutCookie) ==
   1234          CalculateCookiePadding(*this, E).isZero());
   1235   if (allocSize != allocSizeWithoutCookie) {
   1236     assert(E->isArray());
   1237     allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation,
   1238                                                        numElements,
   1239                                                        E, allocType);
   1240   }
   1241 
   1242   llvm::Type *elementPtrTy
   1243     = ConvertTypeForMem(allocType)->getPointerTo(AS);
   1244   llvm::Value *result = Builder.CreateBitCast(allocation, elementPtrTy);
   1245 
   1246   EmitNewInitializer(*this, E, allocType, result, numElements,
   1247                      allocSizeWithoutCookie);
   1248   if (E->isArray()) {
   1249     // NewPtr is a pointer to the base element type.  If we're
   1250     // allocating an array of arrays, we'll need to cast back to the
   1251     // array pointer type.
   1252     llvm::Type *resultType = ConvertTypeForMem(E->getType());
   1253     if (result->getType() != resultType)
   1254       result = Builder.CreateBitCast(result, resultType);
   1255   }
   1256 
   1257   // Deactivate the 'operator delete' cleanup if we finished
   1258   // initialization.
   1259   if (operatorDeleteCleanup.isValid()) {
   1260     DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator);
   1261     cleanupDominator->eraseFromParent();
   1262   }
   1263 
   1264   if (nullCheck) {
   1265     conditional.end(*this);
   1266 
   1267     llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
   1268     EmitBlock(contBB);
   1269 
   1270     llvm::PHINode *PHI = Builder.CreatePHI(result->getType(), 2);
   1271     PHI->addIncoming(result, notNullBB);
   1272     PHI->addIncoming(llvm::Constant::getNullValue(result->getType()),
   1273                      nullCheckBB);
   1274 
   1275     result = PHI;
   1276   }
   1277 
   1278   return result;
   1279 }
   1280 
   1281 void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD,
   1282                                      llvm::Value *Ptr,
   1283                                      QualType DeleteTy) {
   1284   assert(DeleteFD->getOverloadedOperator() == OO_Delete);
   1285 
   1286   const FunctionProtoType *DeleteFTy =
   1287     DeleteFD->getType()->getAs<FunctionProtoType>();
   1288 
   1289   CallArgList DeleteArgs;
   1290 
   1291   // Check if we need to pass the size to the delete operator.
   1292   llvm::Value *Size = 0;
   1293   QualType SizeTy;
   1294   if (DeleteFTy->getNumArgs() == 2) {
   1295     SizeTy = DeleteFTy->getArgType(1);
   1296     CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy);
   1297     Size = llvm::ConstantInt::get(ConvertType(SizeTy),
   1298                                   DeleteTypeSize.getQuantity());
   1299   }
   1300 
   1301   QualType ArgTy = DeleteFTy->getArgType(0);
   1302   llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy));
   1303   DeleteArgs.add(RValue::get(DeletePtr), ArgTy);
   1304 
   1305   if (Size)
   1306     DeleteArgs.add(RValue::get(Size), SizeTy);
   1307 
   1308   // Emit the call to delete.
   1309   EmitCall(CGM.getTypes().arrangeFunctionCall(DeleteArgs, DeleteFTy),
   1310            CGM.GetAddrOfFunction(DeleteFD), ReturnValueSlot(),
   1311            DeleteArgs, DeleteFD);
   1312 }
   1313 
   1314 namespace {
   1315   /// Calls the given 'operator delete' on a single object.
   1316   struct CallObjectDelete : EHScopeStack::Cleanup {
   1317     llvm::Value *Ptr;
   1318     const FunctionDecl *OperatorDelete;
   1319     QualType ElementType;
   1320 
   1321     CallObjectDelete(llvm::Value *Ptr,
   1322                      const FunctionDecl *OperatorDelete,
   1323                      QualType ElementType)
   1324       : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {}
   1325 
   1326     void Emit(CodeGenFunction &CGF, Flags flags) {
   1327       CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType);
   1328     }
   1329   };
   1330 }
   1331 
   1332 /// Emit the code for deleting a single object.
   1333 static void EmitObjectDelete(CodeGenFunction &CGF,
   1334                              const FunctionDecl *OperatorDelete,
   1335                              llvm::Value *Ptr,
   1336                              QualType ElementType,
   1337                              bool UseGlobalDelete) {
   1338   // Find the destructor for the type, if applicable.  If the
   1339   // destructor is virtual, we'll just emit the vcall and return.
   1340   const CXXDestructorDecl *Dtor = 0;
   1341   if (const RecordType *RT = ElementType->getAs<RecordType>()) {
   1342     CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
   1343     if (RD->hasDefinition() && !RD->hasTrivialDestructor()) {
   1344       Dtor = RD->getDestructor();
   1345 
   1346       if (Dtor->isVirtual()) {
   1347         if (UseGlobalDelete) {
   1348           // If we're supposed to call the global delete, make sure we do so
   1349           // even if the destructor throws.
   1350           CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
   1351                                                     Ptr, OperatorDelete,
   1352                                                     ElementType);
   1353         }
   1354 
   1355         llvm::Type *Ty =
   1356           CGF.getTypes().GetFunctionType(
   1357                          CGF.getTypes().arrangeCXXDestructor(Dtor, Dtor_Complete));
   1358 
   1359         llvm::Value *Callee
   1360           = CGF.BuildVirtualCall(Dtor,
   1361                                  UseGlobalDelete? Dtor_Complete : Dtor_Deleting,
   1362                                  Ptr, Ty);
   1363         CGF.EmitCXXMemberCall(Dtor, Callee, ReturnValueSlot(), Ptr, /*VTT=*/0,
   1364                               0, 0);
   1365 
   1366         if (UseGlobalDelete) {
   1367           CGF.PopCleanupBlock();
   1368         }
   1369 
   1370         return;
   1371       }
   1372     }
   1373   }
   1374 
   1375   // Make sure that we call delete even if the dtor throws.
   1376   // This doesn't have to a conditional cleanup because we're going
   1377   // to pop it off in a second.
   1378   CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
   1379                                             Ptr, OperatorDelete, ElementType);
   1380 
   1381   if (Dtor)
   1382     CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
   1383                               /*ForVirtualBase=*/false, Ptr);
   1384   else if (CGF.getLangOpts().ObjCAutoRefCount &&
   1385            ElementType->isObjCLifetimeType()) {
   1386     switch (ElementType.getObjCLifetime()) {
   1387     case Qualifiers::OCL_None:
   1388     case Qualifiers::OCL_ExplicitNone:
   1389     case Qualifiers::OCL_Autoreleasing:
   1390       break;
   1391 
   1392     case Qualifiers::OCL_Strong: {
   1393       // Load the pointer value.
   1394       llvm::Value *PtrValue = CGF.Builder.CreateLoad(Ptr,
   1395                                              ElementType.isVolatileQualified());
   1396 
   1397       CGF.EmitARCRelease(PtrValue, /*precise*/ true);
   1398       break;
   1399     }
   1400 
   1401     case Qualifiers::OCL_Weak:
   1402       CGF.EmitARCDestroyWeak(Ptr);
   1403       break;
   1404     }
   1405   }
   1406 
   1407   CGF.PopCleanupBlock();
   1408 }
   1409 
   1410 namespace {
   1411   /// Calls the given 'operator delete' on an array of objects.
   1412   struct CallArrayDelete : EHScopeStack::Cleanup {
   1413     llvm::Value *Ptr;
   1414     const FunctionDecl *OperatorDelete;
   1415     llvm::Value *NumElements;
   1416     QualType ElementType;
   1417     CharUnits CookieSize;
   1418 
   1419     CallArrayDelete(llvm::Value *Ptr,
   1420                     const FunctionDecl *OperatorDelete,
   1421                     llvm::Value *NumElements,
   1422                     QualType ElementType,
   1423                     CharUnits CookieSize)
   1424       : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements),
   1425         ElementType(ElementType), CookieSize(CookieSize) {}
   1426 
   1427     void Emit(CodeGenFunction &CGF, Flags flags) {
   1428       const FunctionProtoType *DeleteFTy =
   1429         OperatorDelete->getType()->getAs<FunctionProtoType>();
   1430       assert(DeleteFTy->getNumArgs() == 1 || DeleteFTy->getNumArgs() == 2);
   1431 
   1432       CallArgList Args;
   1433 
   1434       // Pass the pointer as the first argument.
   1435       QualType VoidPtrTy = DeleteFTy->getArgType(0);
   1436       llvm::Value *DeletePtr
   1437         = CGF.Builder.CreateBitCast(Ptr, CGF.ConvertType(VoidPtrTy));
   1438       Args.add(RValue::get(DeletePtr), VoidPtrTy);
   1439 
   1440       // Pass the original requested size as the second argument.
   1441       if (DeleteFTy->getNumArgs() == 2) {
   1442         QualType size_t = DeleteFTy->getArgType(1);
   1443         llvm::IntegerType *SizeTy
   1444           = cast<llvm::IntegerType>(CGF.ConvertType(size_t));
   1445 
   1446         CharUnits ElementTypeSize =
   1447           CGF.CGM.getContext().getTypeSizeInChars(ElementType);
   1448 
   1449         // The size of an element, multiplied by the number of elements.
   1450         llvm::Value *Size
   1451           = llvm::ConstantInt::get(SizeTy, ElementTypeSize.getQuantity());
   1452         Size = CGF.Builder.CreateMul(Size, NumElements);
   1453 
   1454         // Plus the size of the cookie if applicable.
   1455         if (!CookieSize.isZero()) {
   1456           llvm::Value *CookieSizeV
   1457             = llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity());
   1458           Size = CGF.Builder.CreateAdd(Size, CookieSizeV);
   1459         }
   1460 
   1461         Args.add(RValue::get(Size), size_t);
   1462       }
   1463 
   1464       // Emit the call to delete.
   1465       CGF.EmitCall(CGF.getTypes().arrangeFunctionCall(Args, DeleteFTy),
   1466                    CGF.CGM.GetAddrOfFunction(OperatorDelete),
   1467                    ReturnValueSlot(), Args, OperatorDelete);
   1468     }
   1469   };
   1470 }
   1471 
   1472 /// Emit the code for deleting an array of objects.
   1473 static void EmitArrayDelete(CodeGenFunction &CGF,
   1474                             const CXXDeleteExpr *E,
   1475                             llvm::Value *deletedPtr,
   1476                             QualType elementType) {
   1477   llvm::Value *numElements = 0;
   1478   llvm::Value *allocatedPtr = 0;
   1479   CharUnits cookieSize;
   1480   CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType,
   1481                                       numElements, allocatedPtr, cookieSize);
   1482 
   1483   assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer");
   1484 
   1485   // Make sure that we call delete even if one of the dtors throws.
   1486   const FunctionDecl *operatorDelete = E->getOperatorDelete();
   1487   CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup,
   1488                                            allocatedPtr, operatorDelete,
   1489                                            numElements, elementType,
   1490                                            cookieSize);
   1491 
   1492   // Destroy the elements.
   1493   if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) {
   1494     assert(numElements && "no element count for a type with a destructor!");
   1495 
   1496     llvm::Value *arrayEnd =
   1497       CGF.Builder.CreateInBoundsGEP(deletedPtr, numElements, "delete.end");
   1498 
   1499     // Note that it is legal to allocate a zero-length array, and we
   1500     // can never fold the check away because the length should always
   1501     // come from a cookie.
   1502     CGF.emitArrayDestroy(deletedPtr, arrayEnd, elementType,
   1503                          CGF.getDestroyer(dtorKind),
   1504                          /*checkZeroLength*/ true,
   1505                          CGF.needsEHCleanup(dtorKind));
   1506   }
   1507 
   1508   // Pop the cleanup block.
   1509   CGF.PopCleanupBlock();
   1510 }
   1511 
   1512 void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) {
   1513 
   1514   // Get at the argument before we performed the implicit conversion
   1515   // to void*.
   1516   const Expr *Arg = E->getArgument();
   1517   while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) {
   1518     if (ICE->getCastKind() != CK_UserDefinedConversion &&
   1519         ICE->getType()->isVoidPointerType())
   1520       Arg = ICE->getSubExpr();
   1521     else
   1522       break;
   1523   }
   1524 
   1525   llvm::Value *Ptr = EmitScalarExpr(Arg);
   1526 
   1527   // Null check the pointer.
   1528   llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull");
   1529   llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end");
   1530 
   1531   llvm::Value *IsNull = Builder.CreateIsNull(Ptr, "isnull");
   1532 
   1533   Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull);
   1534   EmitBlock(DeleteNotNull);
   1535 
   1536   // We might be deleting a pointer to array.  If so, GEP down to the
   1537   // first non-array element.
   1538   // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*)
   1539   QualType DeleteTy = Arg->getType()->getAs<PointerType>()->getPointeeType();
   1540   if (DeleteTy->isConstantArrayType()) {
   1541     llvm::Value *Zero = Builder.getInt32(0);
   1542     SmallVector<llvm::Value*,8> GEP;
   1543 
   1544     GEP.push_back(Zero); // point at the outermost array
   1545 
   1546     // For each layer of array type we're pointing at:
   1547     while (const ConstantArrayType *Arr
   1548              = getContext().getAsConstantArrayType(DeleteTy)) {
   1549       // 1. Unpeel the array type.
   1550       DeleteTy = Arr->getElementType();
   1551 
   1552       // 2. GEP to the first element of the array.
   1553       GEP.push_back(Zero);
   1554     }
   1555 
   1556     Ptr = Builder.CreateInBoundsGEP(Ptr, GEP, "del.first");
   1557   }
   1558 
   1559   assert(ConvertTypeForMem(DeleteTy) ==
   1560          cast<llvm::PointerType>(Ptr->getType())->getElementType());
   1561 
   1562   if (E->isArrayForm()) {
   1563     EmitArrayDelete(*this, E, Ptr, DeleteTy);
   1564   } else {
   1565     EmitObjectDelete(*this, E->getOperatorDelete(), Ptr, DeleteTy,
   1566                      E->isGlobalDelete());
   1567   }
   1568 
   1569   EmitBlock(DeleteEnd);
   1570 }
   1571 
   1572 static llvm::Constant *getBadTypeidFn(CodeGenFunction &CGF) {
   1573   // void __cxa_bad_typeid();
   1574   llvm::FunctionType *FTy = llvm::FunctionType::get(CGF.VoidTy, false);
   1575 
   1576   return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_typeid");
   1577 }
   1578 
   1579 static void EmitBadTypeidCall(CodeGenFunction &CGF) {
   1580   llvm::Value *Fn = getBadTypeidFn(CGF);
   1581   CGF.EmitCallOrInvoke(Fn).setDoesNotReturn();
   1582   CGF.Builder.CreateUnreachable();
   1583 }
   1584 
   1585 static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF,
   1586                                          const Expr *E,
   1587                                          llvm::Type *StdTypeInfoPtrTy) {
   1588   // Get the vtable pointer.
   1589   llvm::Value *ThisPtr = CGF.EmitLValue(E).getAddress();
   1590 
   1591   // C++ [expr.typeid]p2:
   1592   //   If the glvalue expression is obtained by applying the unary * operator to
   1593   //   a pointer and the pointer is a null pointer value, the typeid expression
   1594   //   throws the std::bad_typeid exception.
   1595   if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParens())) {
   1596     if (UO->getOpcode() == UO_Deref) {
   1597       llvm::BasicBlock *BadTypeidBlock =
   1598         CGF.createBasicBlock("typeid.bad_typeid");
   1599       llvm::BasicBlock *EndBlock =
   1600         CGF.createBasicBlock("typeid.end");
   1601 
   1602       llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr);
   1603       CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock);
   1604 
   1605       CGF.EmitBlock(BadTypeidBlock);
   1606       EmitBadTypeidCall(CGF);
   1607       CGF.EmitBlock(EndBlock);
   1608     }
   1609   }
   1610 
   1611   llvm::Value *Value = CGF.GetVTablePtr(ThisPtr,
   1612                                         StdTypeInfoPtrTy->getPointerTo());
   1613 
   1614   // Load the type info.
   1615   Value = CGF.Builder.CreateConstInBoundsGEP1_64(Value, -1ULL);
   1616   return CGF.Builder.CreateLoad(Value);
   1617 }
   1618 
   1619 llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) {
   1620   llvm::Type *StdTypeInfoPtrTy =
   1621     ConvertType(E->getType())->getPointerTo();
   1622 
   1623   if (E->isTypeOperand()) {
   1624     llvm::Constant *TypeInfo =
   1625       CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand());
   1626     return Builder.CreateBitCast(TypeInfo, StdTypeInfoPtrTy);
   1627   }
   1628 
   1629   // C++ [expr.typeid]p2:
   1630   //   When typeid is applied to a glvalue expression whose type is a
   1631   //   polymorphic class type, the result refers to a std::type_info object
   1632   //   representing the type of the most derived object (that is, the dynamic
   1633   //   type) to which the glvalue refers.
   1634   if (E->getExprOperand()->isGLValue()) {
   1635     if (const RecordType *RT =
   1636           E->getExprOperand()->getType()->getAs<RecordType>()) {
   1637       const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
   1638       if (RD->isPolymorphic())
   1639         return EmitTypeidFromVTable(*this, E->getExprOperand(),
   1640                                     StdTypeInfoPtrTy);
   1641     }
   1642   }
   1643 
   1644   QualType OperandTy = E->getExprOperand()->getType();
   1645   return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy),
   1646                                StdTypeInfoPtrTy);
   1647 }
   1648 
   1649 static llvm::Constant *getDynamicCastFn(CodeGenFunction &CGF) {
   1650   // void *__dynamic_cast(const void *sub,
   1651   //                      const abi::__class_type_info *src,
   1652   //                      const abi::__class_type_info *dst,
   1653   //                      std::ptrdiff_t src2dst_offset);
   1654 
   1655   llvm::Type *Int8PtrTy = CGF.Int8PtrTy;
   1656   llvm::Type *PtrDiffTy =
   1657     CGF.ConvertType(CGF.getContext().getPointerDiffType());
   1658 
   1659   llvm::Type *Args[4] = { Int8PtrTy, Int8PtrTy, Int8PtrTy, PtrDiffTy };
   1660 
   1661   llvm::FunctionType *FTy =
   1662     llvm::FunctionType::get(Int8PtrTy, Args, false);
   1663 
   1664   return CGF.CGM.CreateRuntimeFunction(FTy, "__dynamic_cast");
   1665 }
   1666 
   1667 static llvm::Constant *getBadCastFn(CodeGenFunction &CGF) {
   1668   // void __cxa_bad_cast();
   1669   llvm::FunctionType *FTy = llvm::FunctionType::get(CGF.VoidTy, false);
   1670   return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_bad_cast");
   1671 }
   1672 
   1673 static void EmitBadCastCall(CodeGenFunction &CGF) {
   1674   llvm::Value *Fn = getBadCastFn(CGF);
   1675   CGF.EmitCallOrInvoke(Fn).setDoesNotReturn();
   1676   CGF.Builder.CreateUnreachable();
   1677 }
   1678 
   1679 static llvm::Value *
   1680 EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value,
   1681                     QualType SrcTy, QualType DestTy,
   1682                     llvm::BasicBlock *CastEnd) {
   1683   llvm::Type *PtrDiffLTy =
   1684     CGF.ConvertType(CGF.getContext().getPointerDiffType());
   1685   llvm::Type *DestLTy = CGF.ConvertType(DestTy);
   1686 
   1687   if (const PointerType *PTy = DestTy->getAs<PointerType>()) {
   1688     if (PTy->getPointeeType()->isVoidType()) {
   1689       // C++ [expr.dynamic.cast]p7:
   1690       //   If T is "pointer to cv void," then the result is a pointer to the
   1691       //   most derived object pointed to by v.
   1692 
   1693       // Get the vtable pointer.
   1694       llvm::Value *VTable = CGF.GetVTablePtr(Value, PtrDiffLTy->getPointerTo());
   1695 
   1696       // Get the offset-to-top from the vtable.
   1697       llvm::Value *OffsetToTop =
   1698         CGF.Builder.CreateConstInBoundsGEP1_64(VTable, -2ULL);
   1699       OffsetToTop = CGF.Builder.CreateLoad(OffsetToTop, "offset.to.top");
   1700 
   1701       // Finally, add the offset to the pointer.
   1702       Value = CGF.EmitCastToVoidPtr(Value);
   1703       Value = CGF.Builder.CreateInBoundsGEP(Value, OffsetToTop);
   1704 
   1705       return CGF.Builder.CreateBitCast(Value, DestLTy);
   1706     }
   1707   }
   1708 
   1709   QualType SrcRecordTy;
   1710   QualType DestRecordTy;
   1711 
   1712   if (const PointerType *DestPTy = DestTy->getAs<PointerType>()) {
   1713     SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType();
   1714     DestRecordTy = DestPTy->getPointeeType();
   1715   } else {
   1716     SrcRecordTy = SrcTy;
   1717     DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType();
   1718   }
   1719 
   1720   assert(SrcRecordTy->isRecordType() && "source type must be a record type!");
   1721   assert(DestRecordTy->isRecordType() && "dest type must be a record type!");
   1722 
   1723   llvm::Value *SrcRTTI =
   1724     CGF.CGM.GetAddrOfRTTIDescriptor(SrcRecordTy.getUnqualifiedType());
   1725   llvm::Value *DestRTTI =
   1726     CGF.CGM.GetAddrOfRTTIDescriptor(DestRecordTy.getUnqualifiedType());
   1727 
   1728   // FIXME: Actually compute a hint here.
   1729   llvm::Value *OffsetHint = llvm::ConstantInt::get(PtrDiffLTy, -1ULL);
   1730 
   1731   // Emit the call to __dynamic_cast.
   1732   Value = CGF.EmitCastToVoidPtr(Value);
   1733   Value = CGF.Builder.CreateCall4(getDynamicCastFn(CGF), Value,
   1734                                   SrcRTTI, DestRTTI, OffsetHint);
   1735   Value = CGF.Builder.CreateBitCast(Value, DestLTy);
   1736 
   1737   /// C++ [expr.dynamic.cast]p9:
   1738   ///   A failed cast to reference type throws std::bad_cast
   1739   if (DestTy->isReferenceType()) {
   1740     llvm::BasicBlock *BadCastBlock =
   1741       CGF.createBasicBlock("dynamic_cast.bad_cast");
   1742 
   1743     llvm::Value *IsNull = CGF.Builder.CreateIsNull(Value);
   1744     CGF.Builder.CreateCondBr(IsNull, BadCastBlock, CastEnd);
   1745 
   1746     CGF.EmitBlock(BadCastBlock);
   1747     EmitBadCastCall(CGF);
   1748   }
   1749 
   1750   return Value;
   1751 }
   1752 
   1753 static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF,
   1754                                           QualType DestTy) {
   1755   llvm::Type *DestLTy = CGF.ConvertType(DestTy);
   1756   if (DestTy->isPointerType())
   1757     return llvm::Constant::getNullValue(DestLTy);
   1758 
   1759   /// C++ [expr.dynamic.cast]p9:
   1760   ///   A failed cast to reference type throws std::bad_cast
   1761   EmitBadCastCall(CGF);
   1762 
   1763   CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end"));
   1764   return llvm::UndefValue::get(DestLTy);
   1765 }
   1766 
   1767 llvm::Value *CodeGenFunction::EmitDynamicCast(llvm::Value *Value,
   1768                                               const CXXDynamicCastExpr *DCE) {
   1769   QualType DestTy = DCE->getTypeAsWritten();
   1770 
   1771   if (DCE->isAlwaysNull())
   1772     return EmitDynamicCastToNull(*this, DestTy);
   1773 
   1774   QualType SrcTy = DCE->getSubExpr()->getType();
   1775 
   1776   // C++ [expr.dynamic.cast]p4:
   1777   //   If the value of v is a null pointer value in the pointer case, the result
   1778   //   is the null pointer value of type T.
   1779   bool ShouldNullCheckSrcValue = SrcTy->isPointerType();
   1780 
   1781   llvm::BasicBlock *CastNull = 0;
   1782   llvm::BasicBlock *CastNotNull = 0;
   1783   llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end");
   1784 
   1785   if (ShouldNullCheckSrcValue) {
   1786     CastNull = createBasicBlock("dynamic_cast.null");
   1787     CastNotNull = createBasicBlock("dynamic_cast.notnull");
   1788 
   1789     llvm::Value *IsNull = Builder.CreateIsNull(Value);
   1790     Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
   1791     EmitBlock(CastNotNull);
   1792   }
   1793 
   1794   Value = EmitDynamicCastCall(*this, Value, SrcTy, DestTy, CastEnd);
   1795 
   1796   if (ShouldNullCheckSrcValue) {
   1797     EmitBranch(CastEnd);
   1798 
   1799     EmitBlock(CastNull);
   1800     EmitBranch(CastEnd);
   1801   }
   1802 
   1803   EmitBlock(CastEnd);
   1804 
   1805   if (ShouldNullCheckSrcValue) {
   1806     llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
   1807     PHI->addIncoming(Value, CastNotNull);
   1808     PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull);
   1809 
   1810     Value = PHI;
   1811   }
   1812 
   1813   return Value;
   1814 }
   1815 
   1816 void CodeGenFunction::EmitLambdaExpr(const LambdaExpr *E, AggValueSlot Slot) {
   1817   RunCleanupsScope Scope(*this);
   1818   LValue SlotLV = MakeAddrLValue(Slot.getAddr(), E->getType(),
   1819                                  Slot.getAlignment());
   1820 
   1821   CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin();
   1822   for (LambdaExpr::capture_init_iterator i = E->capture_init_begin(),
   1823                                          e = E->capture_init_end();
   1824        i != e; ++i, ++CurField) {
   1825     // Emit initialization
   1826 
   1827     LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
   1828     ArrayRef<VarDecl *> ArrayIndexes;
   1829     if (CurField->getType()->isArrayType())
   1830       ArrayIndexes = E->getCaptureInitIndexVars(i);
   1831     EmitInitializerForField(*CurField, LV, *i, ArrayIndexes);
   1832   }
   1833 }
   1834