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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 
EmitCXXMemberCall(const CXXMethodDecl * MD,llvm::Value * Callee,ReturnValueSlot ReturnValue,llvm::Value * This,llvm::Value * VTT,CallExpr::const_arg_iterator ArgBeg,CallExpr::const_arg_iterator ArgEnd)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 
getMostDerivedClassDecl(const Expr * Base)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.
skipNoOpCastsAndParens(const Expr * E)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.
canDevirtualizeMemberFunctionCalls(ASTContext & Context,const Expr * Base,const CXXMethodDecl * MD)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.
EmitCXXMemberCallExpr(const CXXMemberCallExpr * CE,ReturnValueSlot ReturnValue)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
EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr * E,ReturnValueSlot ReturnValue)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
EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr * E,const CXXMethodDecl * MD,ReturnValueSlot ReturnValue)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 
EmitCUDAKernelCallExpr(const CUDAKernelCallExpr * E,ReturnValueSlot ReturnValue)351 RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E,
352                                                ReturnValueSlot ReturnValue) {
353   return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue);
354 }
355 
EmitNullBaseClassInitialization(CodeGenFunction & CGF,llvm::Value * DestPtr,const CXXRecordDecl * Base)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
EmitCXXConstructExpr(const CXXConstructExpr * E,AggValueSlot Dest)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
EmitSynthesizedCXXCopyCtor(llvm::Value * Dest,llvm::Value * Src,const Expr * Exp)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 
CalculateCookiePadding(CodeGenFunction & CGF,const CXXNewExpr * E)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 
EmitCXXNewAllocSize(CodeGenFunction & CGF,const CXXNewExpr * e,unsigned minElements,llvm::Value * & numElements,llvm::Value * & sizeWithoutCookie)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 
StoreAnyExprIntoOneUnit(CodeGenFunction & CGF,const Expr * Init,QualType AllocType,llvm::Value * NewPtr)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
EmitNewArrayInitializer(const CXXNewExpr * E,QualType elementType,llvm::Value * beginPtr,llvm::Value * numElements)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 
EmitZeroMemSet(CodeGenFunction & CGF,QualType T,llvm::Value * NewPtr,llvm::Value * Size)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 
EmitNewInitializer(CodeGenFunction & CGF,const CXXNewExpr * E,QualType ElementType,llvm::Value * NewPtr,llvm::Value * NumElements,llvm::Value * AllocSizeWithoutCookie)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 
getPlacementArgs()969     RValue *getPlacementArgs() { return reinterpret_cast<RValue*>(this+1); }
970 
971   public:
getExtraSize(size_t NumPlacementArgs)972     static size_t getExtraSize(size_t NumPlacementArgs) {
973       return NumPlacementArgs * sizeof(RValue);
974     }
975 
CallDeleteDuringNew(size_t NumPlacementArgs,const FunctionDecl * OperatorDelete,llvm::Value * Ptr,llvm::Value * AllocSize)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 
setPlacementArg(unsigned I,RValue Arg)983     void setPlacementArg(unsigned I, RValue Arg) {
984       assert(I < NumPlacementArgs && "index out of range");
985       getPlacementArgs()[I] = Arg;
986     }
987 
Emit(CodeGenFunction & CGF,Flags flags)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 
getPlacementArgs()1024     DominatingValue<RValue>::saved_type *getPlacementArgs() {
1025       return reinterpret_cast<DominatingValue<RValue>::saved_type*>(this+1);
1026     }
1027 
1028   public:
getExtraSize(size_t NumPlacementArgs)1029     static size_t getExtraSize(size_t NumPlacementArgs) {
1030       return NumPlacementArgs * sizeof(DominatingValue<RValue>::saved_type);
1031     }
1032 
CallDeleteDuringConditionalNew(size_t NumPlacementArgs,const FunctionDecl * OperatorDelete,DominatingValue<RValue>::saved_type Ptr,DominatingValue<RValue>::saved_type AllocSize)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 
setPlacementArg(unsigned I,DominatingValue<RValue>::saved_type Arg)1040     void setPlacementArg(unsigned I, DominatingValue<RValue>::saved_type Arg) {
1041       assert(I < NumPlacementArgs && "index out of range");
1042       getPlacementArgs()[I] = Arg;
1043     }
1044 
Emit(CodeGenFunction & CGF,Flags flags)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.
EnterNewDeleteCleanup(CodeGenFunction & CGF,const CXXNewExpr * E,llvm::Value * NewPtr,llvm::Value * AllocSize,const CallArgList & NewArgs)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 
EmitCXXNewExpr(const CXXNewExpr * E)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 
EmitDeleteCall(const FunctionDecl * DeleteFD,llvm::Value * Ptr,QualType DeleteTy)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 
CallObjectDelete__anon7f54e8600211::CallObjectDelete1321     CallObjectDelete(llvm::Value *Ptr,
1322                      const FunctionDecl *OperatorDelete,
1323                      QualType ElementType)
1324       : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {}
1325 
Emit__anon7f54e8600211::CallObjectDelete1326     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.
EmitObjectDelete(CodeGenFunction & CGF,const FunctionDecl * OperatorDelete,llvm::Value * Ptr,QualType ElementType,bool UseGlobalDelete)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 
CallArrayDelete__anon7f54e8600311::CallArrayDelete1419     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 
Emit__anon7f54e8600311::CallArrayDelete1427     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.
EmitArrayDelete(CodeGenFunction & CGF,const CXXDeleteExpr * E,llvm::Value * deletedPtr,QualType elementType)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 
EmitCXXDeleteExpr(const CXXDeleteExpr * E)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 
getBadTypeidFn(CodeGenFunction & CGF)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 
EmitBadTypeidCall(CodeGenFunction & CGF)1579 static void EmitBadTypeidCall(CodeGenFunction &CGF) {
1580   llvm::Value *Fn = getBadTypeidFn(CGF);
1581   CGF.EmitCallOrInvoke(Fn).setDoesNotReturn();
1582   CGF.Builder.CreateUnreachable();
1583 }
1584 
EmitTypeidFromVTable(CodeGenFunction & CGF,const Expr * E,llvm::Type * StdTypeInfoPtrTy)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 
EmitCXXTypeidExpr(const CXXTypeidExpr * E)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 
getDynamicCastFn(CodeGenFunction & CGF)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 
getBadCastFn(CodeGenFunction & CGF)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 
EmitBadCastCall(CodeGenFunction & CGF)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 *
EmitDynamicCastCall(CodeGenFunction & CGF,llvm::Value * Value,QualType SrcTy,QualType DestTy,llvm::BasicBlock * CastEnd)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 
EmitDynamicCastToNull(CodeGenFunction & CGF,QualType DestTy)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 
EmitDynamicCast(llvm::Value * Value,const CXXDynamicCastExpr * DCE)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 
EmitLambdaExpr(const LambdaExpr * E,AggValueSlot Slot)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