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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 
EmitCXXMemberCall(const CXXMethodDecl * MD,SourceLocation CallLoc,llvm::Value * Callee,ReturnValueSlot ReturnValue,llvm::Value * This,llvm::Value * ImplicitParam,QualType ImplicitParamTy,CallExpr::const_arg_iterator ArgBeg,CallExpr::const_arg_iterator ArgEnd)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 
getCXXRecord(const Expr * E)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.
EmitCXXMemberCallExpr(const CXXMemberCallExpr * CE,ReturnValueSlot ReturnValue)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
EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr * E,ReturnValueSlot ReturnValue)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
EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr * E,const CXXMethodDecl * MD,ReturnValueSlot ReturnValue)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 
EmitCUDAKernelCallExpr(const CUDAKernelCallExpr * E,ReturnValueSlot ReturnValue)306 RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E,
307                                                ReturnValueSlot ReturnValue) {
308   return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue);
309 }
310 
EmitNullBaseClassInitialization(CodeGenFunction & CGF,llvm::Value * DestPtr,const CXXRecordDecl * Base)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
EmitCXXConstructExpr(const CXXConstructExpr * E,AggValueSlot Dest)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
EmitSynthesizedCXXCopyCtor(llvm::Value * Dest,llvm::Value * Src,const Expr * Exp)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 
CalculateCookiePadding(CodeGenFunction & CGF,const CXXNewExpr * E)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 
EmitCXXNewAllocSize(CodeGenFunction & CGF,const CXXNewExpr * e,unsigned minElements,llvm::Value * & numElements,llvm::Value * & sizeWithoutCookie)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 
StoreAnyExprIntoOneUnit(CodeGenFunction & CGF,const Expr * Init,QualType AllocType,llvm::Value * NewPtr)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
EmitNewArrayInitializer(const CXXNewExpr * E,QualType ElementType,llvm::Value * BeginPtr,llvm::Value * NumElements,llvm::Value * AllocSizeWithoutCookie)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 
EmitNewInitializer(CodeGenFunction & CGF,const CXXNewExpr * E,QualType ElementType,llvm::Value * NewPtr,llvm::Value * NumElements,llvm::Value * AllocSizeWithoutCookie)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.
EmitNewDeleteCall(CodeGenFunction & CGF,const FunctionDecl * Callee,const FunctionProtoType * CalleeType,const CallArgList & Args)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 
EmitBuiltinNewDeleteCall(const FunctionProtoType * Type,const Expr * Arg,bool IsDelete)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 
getPlacementArgs()1059     RValue *getPlacementArgs() { return reinterpret_cast<RValue*>(this+1); }
1060 
1061   public:
getExtraSize(size_t NumPlacementArgs)1062     static size_t getExtraSize(size_t NumPlacementArgs) {
1063       return NumPlacementArgs * sizeof(RValue);
1064     }
1065 
CallDeleteDuringNew(size_t NumPlacementArgs,const FunctionDecl * OperatorDelete,llvm::Value * Ptr,llvm::Value * AllocSize)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 
setPlacementArg(unsigned I,RValue Arg)1073     void setPlacementArg(unsigned I, RValue Arg) {
1074       assert(I < NumPlacementArgs && "index out of range");
1075       getPlacementArgs()[I] = Arg;
1076     }
1077 
Emit(CodeGenFunction & CGF,Flags flags)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 
getPlacementArgs()1112     DominatingValue<RValue>::saved_type *getPlacementArgs() {
1113       return reinterpret_cast<DominatingValue<RValue>::saved_type*>(this+1);
1114     }
1115 
1116   public:
getExtraSize(size_t NumPlacementArgs)1117     static size_t getExtraSize(size_t NumPlacementArgs) {
1118       return NumPlacementArgs * sizeof(DominatingValue<RValue>::saved_type);
1119     }
1120 
CallDeleteDuringConditionalNew(size_t NumPlacementArgs,const FunctionDecl * OperatorDelete,DominatingValue<RValue>::saved_type Ptr,DominatingValue<RValue>::saved_type AllocSize)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 
setPlacementArg(unsigned I,DominatingValue<RValue>::saved_type Arg)1128     void setPlacementArg(unsigned I, DominatingValue<RValue>::saved_type Arg) {
1129       assert(I < NumPlacementArgs && "index out of range");
1130       getPlacementArgs()[I] = Arg;
1131     }
1132 
Emit(CodeGenFunction & CGF,Flags flags)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.
EnterNewDeleteCleanup(CodeGenFunction & CGF,const CXXNewExpr * E,llvm::Value * NewPtr,llvm::Value * AllocSize,const CallArgList & NewArgs)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 
EmitCXXNewExpr(const CXXNewExpr * E)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 
EmitDeleteCall(const FunctionDecl * DeleteFD,llvm::Value * Ptr,QualType DeleteTy)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 
CallObjectDelete__anonc9a85ca00311::CallObjectDelete1378     CallObjectDelete(llvm::Value *Ptr,
1379                      const FunctionDecl *OperatorDelete,
1380                      QualType ElementType)
1381       : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {}
1382 
Emit__anonc9a85ca00311::CallObjectDelete1383     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.
EmitObjectDelete(CodeGenFunction & CGF,const FunctionDecl * OperatorDelete,llvm::Value * Ptr,QualType ElementType,bool UseGlobalDelete)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 
CallArrayDelete__anonc9a85ca00411::CallArrayDelete1478     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 
Emit__anonc9a85ca00411::CallArrayDelete1486     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.
EmitArrayDelete(CodeGenFunction & CGF,const CXXDeleteExpr * E,llvm::Value * deletedPtr,QualType elementType)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 
EmitCXXDeleteExpr(const CXXDeleteExpr * E)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 
EmitTypeidFromVTable(CodeGenFunction & CGF,const Expr * E,llvm::Type * StdTypeInfoPtrTy)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 
EmitCXXTypeidExpr(const CXXTypeidExpr * E)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 
EmitDynamicCastToNull(CodeGenFunction & CGF,QualType DestTy)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 
EmitDynamicCast(llvm::Value * Value,const CXXDynamicCastExpr * DCE)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 
EmitLambdaExpr(const LambdaExpr * E,AggValueSlot Slot)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