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1 //===---- CGBuiltin.cpp - Emit LLVM Code for builtins ---------------------===//
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 to emit Objective-C code as LLVM code.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "CGDebugInfo.h"
15 #include "CGObjCRuntime.h"
16 #include "CodeGenFunction.h"
17 #include "CodeGenModule.h"
18 #include "TargetInfo.h"
19 #include "clang/AST/ASTContext.h"
20 #include "clang/AST/DeclObjC.h"
21 #include "clang/AST/StmtObjC.h"
22 #include "clang/Basic/Diagnostic.h"
23 #include "clang/CodeGen/CGFunctionInfo.h"
24 #include "llvm/ADT/STLExtras.h"
25 #include "llvm/IR/CallSite.h"
26 #include "llvm/IR/DataLayout.h"
27 #include "llvm/IR/InlineAsm.h"
28 using namespace clang;
29 using namespace CodeGen;
30 
31 typedef llvm::PointerIntPair<llvm::Value*,1,bool> TryEmitResult;
32 static TryEmitResult
33 tryEmitARCRetainScalarExpr(CodeGenFunction &CGF, const Expr *e);
34 static RValue AdjustObjCObjectType(CodeGenFunction &CGF,
35                                    QualType ET,
36                                    RValue Result);
37 
38 /// Given the address of a variable of pointer type, find the correct
39 /// null to store into it.
getNullForVariable(Address addr)40 static llvm::Constant *getNullForVariable(Address addr) {
41   llvm::Type *type = addr.getElementType();
42   return llvm::ConstantPointerNull::get(cast<llvm::PointerType>(type));
43 }
44 
45 /// Emits an instance of NSConstantString representing the object.
EmitObjCStringLiteral(const ObjCStringLiteral * E)46 llvm::Value *CodeGenFunction::EmitObjCStringLiteral(const ObjCStringLiteral *E)
47 {
48   llvm::Constant *C =
49       CGM.getObjCRuntime().GenerateConstantString(E->getString()).getPointer();
50   // FIXME: This bitcast should just be made an invariant on the Runtime.
51   return llvm::ConstantExpr::getBitCast(C, ConvertType(E->getType()));
52 }
53 
54 /// EmitObjCBoxedExpr - This routine generates code to call
55 /// the appropriate expression boxing method. This will either be
56 /// one of +[NSNumber numberWith<Type>:], or +[NSString stringWithUTF8String:],
57 /// or [NSValue valueWithBytes:objCType:].
58 ///
59 llvm::Value *
EmitObjCBoxedExpr(const ObjCBoxedExpr * E)60 CodeGenFunction::EmitObjCBoxedExpr(const ObjCBoxedExpr *E) {
61   // Generate the correct selector for this literal's concrete type.
62   // Get the method.
63   const ObjCMethodDecl *BoxingMethod = E->getBoxingMethod();
64   const Expr *SubExpr = E->getSubExpr();
65   assert(BoxingMethod && "BoxingMethod is null");
66   assert(BoxingMethod->isClassMethod() && "BoxingMethod must be a class method");
67   Selector Sel = BoxingMethod->getSelector();
68 
69   // Generate a reference to the class pointer, which will be the receiver.
70   // Assumes that the method was introduced in the class that should be
71   // messaged (avoids pulling it out of the result type).
72   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
73   const ObjCInterfaceDecl *ClassDecl = BoxingMethod->getClassInterface();
74   llvm::Value *Receiver = Runtime.GetClass(*this, ClassDecl);
75 
76   CallArgList Args;
77   const ParmVarDecl *ArgDecl = *BoxingMethod->param_begin();
78   QualType ArgQT = ArgDecl->getType().getUnqualifiedType();
79 
80   // ObjCBoxedExpr supports boxing of structs and unions
81   // via [NSValue valueWithBytes:objCType:]
82   const QualType ValueType(SubExpr->getType().getCanonicalType());
83   if (ValueType->isObjCBoxableRecordType()) {
84     // Emit CodeGen for first parameter
85     // and cast value to correct type
86     Address Temporary = CreateMemTemp(SubExpr->getType());
87     EmitAnyExprToMem(SubExpr, Temporary, Qualifiers(), /*isInit*/ true);
88     Address BitCast = Builder.CreateBitCast(Temporary, ConvertType(ArgQT));
89     Args.add(RValue::get(BitCast.getPointer()), ArgQT);
90 
91     // Create char array to store type encoding
92     std::string Str;
93     getContext().getObjCEncodingForType(ValueType, Str);
94     llvm::Constant *GV = CGM.GetAddrOfConstantCString(Str).getPointer();
95 
96     // Cast type encoding to correct type
97     const ParmVarDecl *EncodingDecl = BoxingMethod->parameters()[1];
98     QualType EncodingQT = EncodingDecl->getType().getUnqualifiedType();
99     llvm::Value *Cast = Builder.CreateBitCast(GV, ConvertType(EncodingQT));
100 
101     Args.add(RValue::get(Cast), EncodingQT);
102   } else {
103     Args.add(EmitAnyExpr(SubExpr), ArgQT);
104   }
105 
106   RValue result = Runtime.GenerateMessageSend(
107       *this, ReturnValueSlot(), BoxingMethod->getReturnType(), Sel, Receiver,
108       Args, ClassDecl, BoxingMethod);
109   return Builder.CreateBitCast(result.getScalarVal(),
110                                ConvertType(E->getType()));
111 }
112 
EmitObjCCollectionLiteral(const Expr * E,const ObjCMethodDecl * MethodWithObjects)113 llvm::Value *CodeGenFunction::EmitObjCCollectionLiteral(const Expr *E,
114                                     const ObjCMethodDecl *MethodWithObjects) {
115   ASTContext &Context = CGM.getContext();
116   const ObjCDictionaryLiteral *DLE = nullptr;
117   const ObjCArrayLiteral *ALE = dyn_cast<ObjCArrayLiteral>(E);
118   if (!ALE)
119     DLE = cast<ObjCDictionaryLiteral>(E);
120 
121   // Compute the type of the array we're initializing.
122   uint64_t NumElements =
123     ALE ? ALE->getNumElements() : DLE->getNumElements();
124   llvm::APInt APNumElements(Context.getTypeSize(Context.getSizeType()),
125                             NumElements);
126   QualType ElementType = Context.getObjCIdType().withConst();
127   QualType ElementArrayType
128     = Context.getConstantArrayType(ElementType, APNumElements,
129                                    ArrayType::Normal, /*IndexTypeQuals=*/0);
130 
131   // Allocate the temporary array(s).
132   Address Objects = CreateMemTemp(ElementArrayType, "objects");
133   Address Keys = Address::invalid();
134   if (DLE)
135     Keys = CreateMemTemp(ElementArrayType, "keys");
136 
137   // In ARC, we may need to do extra work to keep all the keys and
138   // values alive until after the call.
139   SmallVector<llvm::Value *, 16> NeededObjects;
140   bool TrackNeededObjects =
141     (getLangOpts().ObjCAutoRefCount &&
142     CGM.getCodeGenOpts().OptimizationLevel != 0);
143 
144   // Perform the actual initialialization of the array(s).
145   for (uint64_t i = 0; i < NumElements; i++) {
146     if (ALE) {
147       // Emit the element and store it to the appropriate array slot.
148       const Expr *Rhs = ALE->getElement(i);
149       LValue LV = MakeAddrLValue(
150           Builder.CreateConstArrayGEP(Objects, i, getPointerSize()),
151           ElementType, AlignmentSource::Decl);
152 
153       llvm::Value *value = EmitScalarExpr(Rhs);
154       EmitStoreThroughLValue(RValue::get(value), LV, true);
155       if (TrackNeededObjects) {
156         NeededObjects.push_back(value);
157       }
158     } else {
159       // Emit the key and store it to the appropriate array slot.
160       const Expr *Key = DLE->getKeyValueElement(i).Key;
161       LValue KeyLV = MakeAddrLValue(
162           Builder.CreateConstArrayGEP(Keys, i, getPointerSize()),
163           ElementType, AlignmentSource::Decl);
164       llvm::Value *keyValue = EmitScalarExpr(Key);
165       EmitStoreThroughLValue(RValue::get(keyValue), KeyLV, /*isInit=*/true);
166 
167       // Emit the value and store it to the appropriate array slot.
168       const Expr *Value = DLE->getKeyValueElement(i).Value;
169       LValue ValueLV = MakeAddrLValue(
170           Builder.CreateConstArrayGEP(Objects, i, getPointerSize()),
171           ElementType, AlignmentSource::Decl);
172       llvm::Value *valueValue = EmitScalarExpr(Value);
173       EmitStoreThroughLValue(RValue::get(valueValue), ValueLV, /*isInit=*/true);
174       if (TrackNeededObjects) {
175         NeededObjects.push_back(keyValue);
176         NeededObjects.push_back(valueValue);
177       }
178     }
179   }
180 
181   // Generate the argument list.
182   CallArgList Args;
183   ObjCMethodDecl::param_const_iterator PI = MethodWithObjects->param_begin();
184   const ParmVarDecl *argDecl = *PI++;
185   QualType ArgQT = argDecl->getType().getUnqualifiedType();
186   Args.add(RValue::get(Objects.getPointer()), ArgQT);
187   if (DLE) {
188     argDecl = *PI++;
189     ArgQT = argDecl->getType().getUnqualifiedType();
190     Args.add(RValue::get(Keys.getPointer()), ArgQT);
191   }
192   argDecl = *PI;
193   ArgQT = argDecl->getType().getUnqualifiedType();
194   llvm::Value *Count =
195     llvm::ConstantInt::get(CGM.getTypes().ConvertType(ArgQT), NumElements);
196   Args.add(RValue::get(Count), ArgQT);
197 
198   // Generate a reference to the class pointer, which will be the receiver.
199   Selector Sel = MethodWithObjects->getSelector();
200   QualType ResultType = E->getType();
201   const ObjCObjectPointerType *InterfacePointerType
202     = ResultType->getAsObjCInterfacePointerType();
203   ObjCInterfaceDecl *Class
204     = InterfacePointerType->getObjectType()->getInterface();
205   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
206   llvm::Value *Receiver = Runtime.GetClass(*this, Class);
207 
208   // Generate the message send.
209   RValue result = Runtime.GenerateMessageSend(
210       *this, ReturnValueSlot(), MethodWithObjects->getReturnType(), Sel,
211       Receiver, Args, Class, MethodWithObjects);
212 
213   // The above message send needs these objects, but in ARC they are
214   // passed in a buffer that is essentially __unsafe_unretained.
215   // Therefore we must prevent the optimizer from releasing them until
216   // after the call.
217   if (TrackNeededObjects) {
218     EmitARCIntrinsicUse(NeededObjects);
219   }
220 
221   return Builder.CreateBitCast(result.getScalarVal(),
222                                ConvertType(E->getType()));
223 }
224 
EmitObjCArrayLiteral(const ObjCArrayLiteral * E)225 llvm::Value *CodeGenFunction::EmitObjCArrayLiteral(const ObjCArrayLiteral *E) {
226   return EmitObjCCollectionLiteral(E, E->getArrayWithObjectsMethod());
227 }
228 
EmitObjCDictionaryLiteral(const ObjCDictionaryLiteral * E)229 llvm::Value *CodeGenFunction::EmitObjCDictionaryLiteral(
230                                             const ObjCDictionaryLiteral *E) {
231   return EmitObjCCollectionLiteral(E, E->getDictWithObjectsMethod());
232 }
233 
234 /// Emit a selector.
EmitObjCSelectorExpr(const ObjCSelectorExpr * E)235 llvm::Value *CodeGenFunction::EmitObjCSelectorExpr(const ObjCSelectorExpr *E) {
236   // Untyped selector.
237   // Note that this implementation allows for non-constant strings to be passed
238   // as arguments to @selector().  Currently, the only thing preventing this
239   // behaviour is the type checking in the front end.
240   return CGM.getObjCRuntime().GetSelector(*this, E->getSelector());
241 }
242 
EmitObjCProtocolExpr(const ObjCProtocolExpr * E)243 llvm::Value *CodeGenFunction::EmitObjCProtocolExpr(const ObjCProtocolExpr *E) {
244   // FIXME: This should pass the Decl not the name.
245   return CGM.getObjCRuntime().GenerateProtocolRef(*this, E->getProtocol());
246 }
247 
248 /// \brief Adjust the type of an Objective-C object that doesn't match up due
249 /// to type erasure at various points, e.g., related result types or the use
250 /// of parameterized classes.
AdjustObjCObjectType(CodeGenFunction & CGF,QualType ExpT,RValue Result)251 static RValue AdjustObjCObjectType(CodeGenFunction &CGF, QualType ExpT,
252                                    RValue Result) {
253   if (!ExpT->isObjCRetainableType())
254     return Result;
255 
256   // If the converted types are the same, we're done.
257   llvm::Type *ExpLLVMTy = CGF.ConvertType(ExpT);
258   if (ExpLLVMTy == Result.getScalarVal()->getType())
259     return Result;
260 
261   // We have applied a substitution. Cast the rvalue appropriately.
262   return RValue::get(CGF.Builder.CreateBitCast(Result.getScalarVal(),
263                                                ExpLLVMTy));
264 }
265 
266 /// Decide whether to extend the lifetime of the receiver of a
267 /// returns-inner-pointer message.
268 static bool
shouldExtendReceiverForInnerPointerMessage(const ObjCMessageExpr * message)269 shouldExtendReceiverForInnerPointerMessage(const ObjCMessageExpr *message) {
270   switch (message->getReceiverKind()) {
271 
272   // For a normal instance message, we should extend unless the
273   // receiver is loaded from a variable with precise lifetime.
274   case ObjCMessageExpr::Instance: {
275     const Expr *receiver = message->getInstanceReceiver();
276 
277     // Look through OVEs.
278     if (auto opaque = dyn_cast<OpaqueValueExpr>(receiver)) {
279       if (opaque->getSourceExpr())
280         receiver = opaque->getSourceExpr()->IgnoreParens();
281     }
282 
283     const ImplicitCastExpr *ice = dyn_cast<ImplicitCastExpr>(receiver);
284     if (!ice || ice->getCastKind() != CK_LValueToRValue) return true;
285     receiver = ice->getSubExpr()->IgnoreParens();
286 
287     // Look through OVEs.
288     if (auto opaque = dyn_cast<OpaqueValueExpr>(receiver)) {
289       if (opaque->getSourceExpr())
290         receiver = opaque->getSourceExpr()->IgnoreParens();
291     }
292 
293     // Only __strong variables.
294     if (receiver->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
295       return true;
296 
297     // All ivars and fields have precise lifetime.
298     if (isa<MemberExpr>(receiver) || isa<ObjCIvarRefExpr>(receiver))
299       return false;
300 
301     // Otherwise, check for variables.
302     const DeclRefExpr *declRef = dyn_cast<DeclRefExpr>(ice->getSubExpr());
303     if (!declRef) return true;
304     const VarDecl *var = dyn_cast<VarDecl>(declRef->getDecl());
305     if (!var) return true;
306 
307     // All variables have precise lifetime except local variables with
308     // automatic storage duration that aren't specially marked.
309     return (var->hasLocalStorage() &&
310             !var->hasAttr<ObjCPreciseLifetimeAttr>());
311   }
312 
313   case ObjCMessageExpr::Class:
314   case ObjCMessageExpr::SuperClass:
315     // It's never necessary for class objects.
316     return false;
317 
318   case ObjCMessageExpr::SuperInstance:
319     // We generally assume that 'self' lives throughout a method call.
320     return false;
321   }
322 
323   llvm_unreachable("invalid receiver kind");
324 }
325 
326 /// Given an expression of ObjC pointer type, check whether it was
327 /// immediately loaded from an ARC __weak l-value.
findWeakLValue(const Expr * E)328 static const Expr *findWeakLValue(const Expr *E) {
329   assert(E->getType()->isObjCRetainableType());
330   E = E->IgnoreParens();
331   if (auto CE = dyn_cast<CastExpr>(E)) {
332     if (CE->getCastKind() == CK_LValueToRValue) {
333       if (CE->getSubExpr()->getType().getObjCLifetime() == Qualifiers::OCL_Weak)
334         return CE->getSubExpr();
335     }
336   }
337 
338   return nullptr;
339 }
340 
EmitObjCMessageExpr(const ObjCMessageExpr * E,ReturnValueSlot Return)341 RValue CodeGenFunction::EmitObjCMessageExpr(const ObjCMessageExpr *E,
342                                             ReturnValueSlot Return) {
343   // Only the lookup mechanism and first two arguments of the method
344   // implementation vary between runtimes.  We can get the receiver and
345   // arguments in generic code.
346 
347   bool isDelegateInit = E->isDelegateInitCall();
348 
349   const ObjCMethodDecl *method = E->getMethodDecl();
350 
351   // If the method is -retain, and the receiver's being loaded from
352   // a __weak variable, peephole the entire operation to objc_loadWeakRetained.
353   if (method && E->getReceiverKind() == ObjCMessageExpr::Instance &&
354       method->getMethodFamily() == OMF_retain) {
355     if (auto lvalueExpr = findWeakLValue(E->getInstanceReceiver())) {
356       LValue lvalue = EmitLValue(lvalueExpr);
357       llvm::Value *result = EmitARCLoadWeakRetained(lvalue.getAddress());
358       return AdjustObjCObjectType(*this, E->getType(), RValue::get(result));
359     }
360   }
361 
362   // We don't retain the receiver in delegate init calls, and this is
363   // safe because the receiver value is always loaded from 'self',
364   // which we zero out.  We don't want to Block_copy block receivers,
365   // though.
366   bool retainSelf =
367     (!isDelegateInit &&
368      CGM.getLangOpts().ObjCAutoRefCount &&
369      method &&
370      method->hasAttr<NSConsumesSelfAttr>());
371 
372   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
373   bool isSuperMessage = false;
374   bool isClassMessage = false;
375   ObjCInterfaceDecl *OID = nullptr;
376   // Find the receiver
377   QualType ReceiverType;
378   llvm::Value *Receiver = nullptr;
379   switch (E->getReceiverKind()) {
380   case ObjCMessageExpr::Instance:
381     ReceiverType = E->getInstanceReceiver()->getType();
382     if (retainSelf) {
383       TryEmitResult ter = tryEmitARCRetainScalarExpr(*this,
384                                                    E->getInstanceReceiver());
385       Receiver = ter.getPointer();
386       if (ter.getInt()) retainSelf = false;
387     } else
388       Receiver = EmitScalarExpr(E->getInstanceReceiver());
389     break;
390 
391   case ObjCMessageExpr::Class: {
392     ReceiverType = E->getClassReceiver();
393     const ObjCObjectType *ObjTy = ReceiverType->getAs<ObjCObjectType>();
394     assert(ObjTy && "Invalid Objective-C class message send");
395     OID = ObjTy->getInterface();
396     assert(OID && "Invalid Objective-C class message send");
397     Receiver = Runtime.GetClass(*this, OID);
398     isClassMessage = true;
399     break;
400   }
401 
402   case ObjCMessageExpr::SuperInstance:
403     ReceiverType = E->getSuperType();
404     Receiver = LoadObjCSelf();
405     isSuperMessage = true;
406     break;
407 
408   case ObjCMessageExpr::SuperClass:
409     ReceiverType = E->getSuperType();
410     Receiver = LoadObjCSelf();
411     isSuperMessage = true;
412     isClassMessage = true;
413     break;
414   }
415 
416   if (retainSelf)
417     Receiver = EmitARCRetainNonBlock(Receiver);
418 
419   // In ARC, we sometimes want to "extend the lifetime"
420   // (i.e. retain+autorelease) of receivers of returns-inner-pointer
421   // messages.
422   if (getLangOpts().ObjCAutoRefCount && method &&
423       method->hasAttr<ObjCReturnsInnerPointerAttr>() &&
424       shouldExtendReceiverForInnerPointerMessage(E))
425     Receiver = EmitARCRetainAutorelease(ReceiverType, Receiver);
426 
427   QualType ResultType = method ? method->getReturnType() : E->getType();
428 
429   CallArgList Args;
430   EmitCallArgs(Args, method, E->arguments());
431 
432   // For delegate init calls in ARC, do an unsafe store of null into
433   // self.  This represents the call taking direct ownership of that
434   // value.  We have to do this after emitting the other call
435   // arguments because they might also reference self, but we don't
436   // have to worry about any of them modifying self because that would
437   // be an undefined read and write of an object in unordered
438   // expressions.
439   if (isDelegateInit) {
440     assert(getLangOpts().ObjCAutoRefCount &&
441            "delegate init calls should only be marked in ARC");
442 
443     // Do an unsafe store of null into self.
444     Address selfAddr =
445       GetAddrOfLocalVar(cast<ObjCMethodDecl>(CurCodeDecl)->getSelfDecl());
446     Builder.CreateStore(getNullForVariable(selfAddr), selfAddr);
447   }
448 
449   RValue result;
450   if (isSuperMessage) {
451     // super is only valid in an Objective-C method
452     const ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(CurFuncDecl);
453     bool isCategoryImpl = isa<ObjCCategoryImplDecl>(OMD->getDeclContext());
454     result = Runtime.GenerateMessageSendSuper(*this, Return, ResultType,
455                                               E->getSelector(),
456                                               OMD->getClassInterface(),
457                                               isCategoryImpl,
458                                               Receiver,
459                                               isClassMessage,
460                                               Args,
461                                               method);
462   } else {
463     result = Runtime.GenerateMessageSend(*this, Return, ResultType,
464                                          E->getSelector(),
465                                          Receiver, Args, OID,
466                                          method);
467   }
468 
469   // For delegate init calls in ARC, implicitly store the result of
470   // the call back into self.  This takes ownership of the value.
471   if (isDelegateInit) {
472     Address selfAddr =
473       GetAddrOfLocalVar(cast<ObjCMethodDecl>(CurCodeDecl)->getSelfDecl());
474     llvm::Value *newSelf = result.getScalarVal();
475 
476     // The delegate return type isn't necessarily a matching type; in
477     // fact, it's quite likely to be 'id'.
478     llvm::Type *selfTy = selfAddr.getElementType();
479     newSelf = Builder.CreateBitCast(newSelf, selfTy);
480 
481     Builder.CreateStore(newSelf, selfAddr);
482   }
483 
484   return AdjustObjCObjectType(*this, E->getType(), result);
485 }
486 
487 namespace {
488 struct FinishARCDealloc final : EHScopeStack::Cleanup {
Emit__anon677e44b40111::FinishARCDealloc489   void Emit(CodeGenFunction &CGF, Flags flags) override {
490     const ObjCMethodDecl *method = cast<ObjCMethodDecl>(CGF.CurCodeDecl);
491 
492     const ObjCImplDecl *impl = cast<ObjCImplDecl>(method->getDeclContext());
493     const ObjCInterfaceDecl *iface = impl->getClassInterface();
494     if (!iface->getSuperClass()) return;
495 
496     bool isCategory = isa<ObjCCategoryImplDecl>(impl);
497 
498     // Call [super dealloc] if we have a superclass.
499     llvm::Value *self = CGF.LoadObjCSelf();
500 
501     CallArgList args;
502     CGF.CGM.getObjCRuntime().GenerateMessageSendSuper(CGF, ReturnValueSlot(),
503                                                       CGF.getContext().VoidTy,
504                                                       method->getSelector(),
505                                                       iface,
506                                                       isCategory,
507                                                       self,
508                                                       /*is class msg*/ false,
509                                                       args,
510                                                       method);
511   }
512 };
513 }
514 
515 /// StartObjCMethod - Begin emission of an ObjCMethod. This generates
516 /// the LLVM function and sets the other context used by
517 /// CodeGenFunction.
StartObjCMethod(const ObjCMethodDecl * OMD,const ObjCContainerDecl * CD)518 void CodeGenFunction::StartObjCMethod(const ObjCMethodDecl *OMD,
519                                       const ObjCContainerDecl *CD) {
520   SourceLocation StartLoc = OMD->getLocStart();
521   FunctionArgList args;
522   // Check if we should generate debug info for this method.
523   if (OMD->hasAttr<NoDebugAttr>())
524     DebugInfo = nullptr; // disable debug info indefinitely for this function
525 
526   llvm::Function *Fn = CGM.getObjCRuntime().GenerateMethod(OMD, CD);
527 
528   const CGFunctionInfo &FI = CGM.getTypes().arrangeObjCMethodDeclaration(OMD);
529   CGM.SetInternalFunctionAttributes(OMD, Fn, FI);
530 
531   args.push_back(OMD->getSelfDecl());
532   args.push_back(OMD->getCmdDecl());
533 
534   args.append(OMD->param_begin(), OMD->param_end());
535 
536   CurGD = OMD;
537   CurEHLocation = OMD->getLocEnd();
538 
539   StartFunction(OMD, OMD->getReturnType(), Fn, FI, args,
540                 OMD->getLocation(), StartLoc);
541 
542   // In ARC, certain methods get an extra cleanup.
543   if (CGM.getLangOpts().ObjCAutoRefCount &&
544       OMD->isInstanceMethod() &&
545       OMD->getSelector().isUnarySelector()) {
546     const IdentifierInfo *ident =
547       OMD->getSelector().getIdentifierInfoForSlot(0);
548     if (ident->isStr("dealloc"))
549       EHStack.pushCleanup<FinishARCDealloc>(getARCCleanupKind());
550   }
551 }
552 
553 static llvm::Value *emitARCRetainLoadOfScalar(CodeGenFunction &CGF,
554                                               LValue lvalue, QualType type);
555 
556 /// Generate an Objective-C method.  An Objective-C method is a C function with
557 /// its pointer, name, and types registered in the class struture.
GenerateObjCMethod(const ObjCMethodDecl * OMD)558 void CodeGenFunction::GenerateObjCMethod(const ObjCMethodDecl *OMD) {
559   StartObjCMethod(OMD, OMD->getClassInterface());
560   PGO.assignRegionCounters(GlobalDecl(OMD), CurFn);
561   assert(isa<CompoundStmt>(OMD->getBody()));
562   incrementProfileCounter(OMD->getBody());
563   EmitCompoundStmtWithoutScope(*cast<CompoundStmt>(OMD->getBody()));
564   FinishFunction(OMD->getBodyRBrace());
565 }
566 
567 /// emitStructGetterCall - Call the runtime function to load a property
568 /// into the return value slot.
emitStructGetterCall(CodeGenFunction & CGF,ObjCIvarDecl * ivar,bool isAtomic,bool hasStrong)569 static void emitStructGetterCall(CodeGenFunction &CGF, ObjCIvarDecl *ivar,
570                                  bool isAtomic, bool hasStrong) {
571   ASTContext &Context = CGF.getContext();
572 
573   Address src =
574     CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), CGF.LoadObjCSelf(), ivar, 0)
575        .getAddress();
576 
577   // objc_copyStruct (ReturnValue, &structIvar,
578   //                  sizeof (Type of Ivar), isAtomic, false);
579   CallArgList args;
580 
581   Address dest = CGF.Builder.CreateBitCast(CGF.ReturnValue, CGF.VoidPtrTy);
582   args.add(RValue::get(dest.getPointer()), Context.VoidPtrTy);
583 
584   src = CGF.Builder.CreateBitCast(src, CGF.VoidPtrTy);
585   args.add(RValue::get(src.getPointer()), Context.VoidPtrTy);
586 
587   CharUnits size = CGF.getContext().getTypeSizeInChars(ivar->getType());
588   args.add(RValue::get(CGF.CGM.getSize(size)), Context.getSizeType());
589   args.add(RValue::get(CGF.Builder.getInt1(isAtomic)), Context.BoolTy);
590   args.add(RValue::get(CGF.Builder.getInt1(hasStrong)), Context.BoolTy);
591 
592   llvm::Value *fn = CGF.CGM.getObjCRuntime().GetGetStructFunction();
593   CGF.EmitCall(CGF.getTypes().arrangeFreeFunctionCall(Context.VoidTy, args,
594                                                       FunctionType::ExtInfo(),
595                                                       RequiredArgs::All),
596                fn, ReturnValueSlot(), args);
597 }
598 
599 /// Determine whether the given architecture supports unaligned atomic
600 /// accesses.  They don't have to be fast, just faster than a function
601 /// call and a mutex.
hasUnalignedAtomics(llvm::Triple::ArchType arch)602 static bool hasUnalignedAtomics(llvm::Triple::ArchType arch) {
603   // FIXME: Allow unaligned atomic load/store on x86.  (It is not
604   // currently supported by the backend.)
605   return 0;
606 }
607 
608 /// Return the maximum size that permits atomic accesses for the given
609 /// architecture.
getMaxAtomicAccessSize(CodeGenModule & CGM,llvm::Triple::ArchType arch)610 static CharUnits getMaxAtomicAccessSize(CodeGenModule &CGM,
611                                         llvm::Triple::ArchType arch) {
612   // ARM has 8-byte atomic accesses, but it's not clear whether we
613   // want to rely on them here.
614 
615   // In the default case, just assume that any size up to a pointer is
616   // fine given adequate alignment.
617   return CharUnits::fromQuantity(CGM.PointerSizeInBytes);
618 }
619 
620 namespace {
621   class PropertyImplStrategy {
622   public:
623     enum StrategyKind {
624       /// The 'native' strategy is to use the architecture's provided
625       /// reads and writes.
626       Native,
627 
628       /// Use objc_setProperty and objc_getProperty.
629       GetSetProperty,
630 
631       /// Use objc_setProperty for the setter, but use expression
632       /// evaluation for the getter.
633       SetPropertyAndExpressionGet,
634 
635       /// Use objc_copyStruct.
636       CopyStruct,
637 
638       /// The 'expression' strategy is to emit normal assignment or
639       /// lvalue-to-rvalue expressions.
640       Expression
641     };
642 
getKind() const643     StrategyKind getKind() const { return StrategyKind(Kind); }
644 
hasStrongMember() const645     bool hasStrongMember() const { return HasStrong; }
isAtomic() const646     bool isAtomic() const { return IsAtomic; }
isCopy() const647     bool isCopy() const { return IsCopy; }
648 
getIvarSize() const649     CharUnits getIvarSize() const { return IvarSize; }
getIvarAlignment() const650     CharUnits getIvarAlignment() const { return IvarAlignment; }
651 
652     PropertyImplStrategy(CodeGenModule &CGM,
653                          const ObjCPropertyImplDecl *propImpl);
654 
655   private:
656     unsigned Kind : 8;
657     unsigned IsAtomic : 1;
658     unsigned IsCopy : 1;
659     unsigned HasStrong : 1;
660 
661     CharUnits IvarSize;
662     CharUnits IvarAlignment;
663   };
664 }
665 
666 /// Pick an implementation strategy for the given property synthesis.
PropertyImplStrategy(CodeGenModule & CGM,const ObjCPropertyImplDecl * propImpl)667 PropertyImplStrategy::PropertyImplStrategy(CodeGenModule &CGM,
668                                      const ObjCPropertyImplDecl *propImpl) {
669   const ObjCPropertyDecl *prop = propImpl->getPropertyDecl();
670   ObjCPropertyDecl::SetterKind setterKind = prop->getSetterKind();
671 
672   IsCopy = (setterKind == ObjCPropertyDecl::Copy);
673   IsAtomic = prop->isAtomic();
674   HasStrong = false; // doesn't matter here.
675 
676   // Evaluate the ivar's size and alignment.
677   ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
678   QualType ivarType = ivar->getType();
679   std::tie(IvarSize, IvarAlignment) =
680       CGM.getContext().getTypeInfoInChars(ivarType);
681 
682   // If we have a copy property, we always have to use getProperty/setProperty.
683   // TODO: we could actually use setProperty and an expression for non-atomics.
684   if (IsCopy) {
685     Kind = GetSetProperty;
686     return;
687   }
688 
689   // Handle retain.
690   if (setterKind == ObjCPropertyDecl::Retain) {
691     // In GC-only, there's nothing special that needs to be done.
692     if (CGM.getLangOpts().getGC() == LangOptions::GCOnly) {
693       // fallthrough
694 
695     // In ARC, if the property is non-atomic, use expression emission,
696     // which translates to objc_storeStrong.  This isn't required, but
697     // it's slightly nicer.
698     } else if (CGM.getLangOpts().ObjCAutoRefCount && !IsAtomic) {
699       // Using standard expression emission for the setter is only
700       // acceptable if the ivar is __strong, which won't be true if
701       // the property is annotated with __attribute__((NSObject)).
702       // TODO: falling all the way back to objc_setProperty here is
703       // just laziness, though;  we could still use objc_storeStrong
704       // if we hacked it right.
705       if (ivarType.getObjCLifetime() == Qualifiers::OCL_Strong)
706         Kind = Expression;
707       else
708         Kind = SetPropertyAndExpressionGet;
709       return;
710 
711     // Otherwise, we need to at least use setProperty.  However, if
712     // the property isn't atomic, we can use normal expression
713     // emission for the getter.
714     } else if (!IsAtomic) {
715       Kind = SetPropertyAndExpressionGet;
716       return;
717 
718     // Otherwise, we have to use both setProperty and getProperty.
719     } else {
720       Kind = GetSetProperty;
721       return;
722     }
723   }
724 
725   // If we're not atomic, just use expression accesses.
726   if (!IsAtomic) {
727     Kind = Expression;
728     return;
729   }
730 
731   // Properties on bitfield ivars need to be emitted using expression
732   // accesses even if they're nominally atomic.
733   if (ivar->isBitField()) {
734     Kind = Expression;
735     return;
736   }
737 
738   // GC-qualified or ARC-qualified ivars need to be emitted as
739   // expressions.  This actually works out to being atomic anyway,
740   // except for ARC __strong, but that should trigger the above code.
741   if (ivarType.hasNonTrivialObjCLifetime() ||
742       (CGM.getLangOpts().getGC() &&
743        CGM.getContext().getObjCGCAttrKind(ivarType))) {
744     Kind = Expression;
745     return;
746   }
747 
748   // Compute whether the ivar has strong members.
749   if (CGM.getLangOpts().getGC())
750     if (const RecordType *recordType = ivarType->getAs<RecordType>())
751       HasStrong = recordType->getDecl()->hasObjectMember();
752 
753   // We can never access structs with object members with a native
754   // access, because we need to use write barriers.  This is what
755   // objc_copyStruct is for.
756   if (HasStrong) {
757     Kind = CopyStruct;
758     return;
759   }
760 
761   // Otherwise, this is target-dependent and based on the size and
762   // alignment of the ivar.
763 
764   // If the size of the ivar is not a power of two, give up.  We don't
765   // want to get into the business of doing compare-and-swaps.
766   if (!IvarSize.isPowerOfTwo()) {
767     Kind = CopyStruct;
768     return;
769   }
770 
771   llvm::Triple::ArchType arch =
772     CGM.getTarget().getTriple().getArch();
773 
774   // Most architectures require memory to fit within a single cache
775   // line, so the alignment has to be at least the size of the access.
776   // Otherwise we have to grab a lock.
777   if (IvarAlignment < IvarSize && !hasUnalignedAtomics(arch)) {
778     Kind = CopyStruct;
779     return;
780   }
781 
782   // If the ivar's size exceeds the architecture's maximum atomic
783   // access size, we have to use CopyStruct.
784   if (IvarSize > getMaxAtomicAccessSize(CGM, arch)) {
785     Kind = CopyStruct;
786     return;
787   }
788 
789   // Otherwise, we can use native loads and stores.
790   Kind = Native;
791 }
792 
793 /// \brief Generate an Objective-C property getter function.
794 ///
795 /// The given Decl must be an ObjCImplementationDecl. \@synthesize
796 /// is illegal within a category.
GenerateObjCGetter(ObjCImplementationDecl * IMP,const ObjCPropertyImplDecl * PID)797 void CodeGenFunction::GenerateObjCGetter(ObjCImplementationDecl *IMP,
798                                          const ObjCPropertyImplDecl *PID) {
799   llvm::Constant *AtomicHelperFn =
800       CodeGenFunction(CGM).GenerateObjCAtomicGetterCopyHelperFunction(PID);
801   const ObjCPropertyDecl *PD = PID->getPropertyDecl();
802   ObjCMethodDecl *OMD = PD->getGetterMethodDecl();
803   assert(OMD && "Invalid call to generate getter (empty method)");
804   StartObjCMethod(OMD, IMP->getClassInterface());
805 
806   generateObjCGetterBody(IMP, PID, OMD, AtomicHelperFn);
807 
808   FinishFunction();
809 }
810 
hasTrivialGetExpr(const ObjCPropertyImplDecl * propImpl)811 static bool hasTrivialGetExpr(const ObjCPropertyImplDecl *propImpl) {
812   const Expr *getter = propImpl->getGetterCXXConstructor();
813   if (!getter) return true;
814 
815   // Sema only makes only of these when the ivar has a C++ class type,
816   // so the form is pretty constrained.
817 
818   // If the property has a reference type, we might just be binding a
819   // reference, in which case the result will be a gl-value.  We should
820   // treat this as a non-trivial operation.
821   if (getter->isGLValue())
822     return false;
823 
824   // If we selected a trivial copy-constructor, we're okay.
825   if (const CXXConstructExpr *construct = dyn_cast<CXXConstructExpr>(getter))
826     return (construct->getConstructor()->isTrivial());
827 
828   // The constructor might require cleanups (in which case it's never
829   // trivial).
830   assert(isa<ExprWithCleanups>(getter));
831   return false;
832 }
833 
834 /// emitCPPObjectAtomicGetterCall - Call the runtime function to
835 /// copy the ivar into the resturn slot.
emitCPPObjectAtomicGetterCall(CodeGenFunction & CGF,llvm::Value * returnAddr,ObjCIvarDecl * ivar,llvm::Constant * AtomicHelperFn)836 static void emitCPPObjectAtomicGetterCall(CodeGenFunction &CGF,
837                                           llvm::Value *returnAddr,
838                                           ObjCIvarDecl *ivar,
839                                           llvm::Constant *AtomicHelperFn) {
840   // objc_copyCppObjectAtomic (&returnSlot, &CppObjectIvar,
841   //                           AtomicHelperFn);
842   CallArgList args;
843 
844   // The 1st argument is the return Slot.
845   args.add(RValue::get(returnAddr), CGF.getContext().VoidPtrTy);
846 
847   // The 2nd argument is the address of the ivar.
848   llvm::Value *ivarAddr =
849     CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(),
850                           CGF.LoadObjCSelf(), ivar, 0).getPointer();
851   ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
852   args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
853 
854   // Third argument is the helper function.
855   args.add(RValue::get(AtomicHelperFn), CGF.getContext().VoidPtrTy);
856 
857   llvm::Value *copyCppAtomicObjectFn =
858     CGF.CGM.getObjCRuntime().GetCppAtomicObjectGetFunction();
859   CGF.EmitCall(CGF.getTypes().arrangeFreeFunctionCall(CGF.getContext().VoidTy,
860                                                       args,
861                                                       FunctionType::ExtInfo(),
862                                                       RequiredArgs::All),
863                copyCppAtomicObjectFn, ReturnValueSlot(), args);
864 }
865 
866 void
generateObjCGetterBody(const ObjCImplementationDecl * classImpl,const ObjCPropertyImplDecl * propImpl,const ObjCMethodDecl * GetterMethodDecl,llvm::Constant * AtomicHelperFn)867 CodeGenFunction::generateObjCGetterBody(const ObjCImplementationDecl *classImpl,
868                                         const ObjCPropertyImplDecl *propImpl,
869                                         const ObjCMethodDecl *GetterMethodDecl,
870                                         llvm::Constant *AtomicHelperFn) {
871   // If there's a non-trivial 'get' expression, we just have to emit that.
872   if (!hasTrivialGetExpr(propImpl)) {
873     if (!AtomicHelperFn) {
874       ReturnStmt ret(SourceLocation(), propImpl->getGetterCXXConstructor(),
875                      /*nrvo*/ nullptr);
876       EmitReturnStmt(ret);
877     }
878     else {
879       ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
880       emitCPPObjectAtomicGetterCall(*this, ReturnValue.getPointer(),
881                                     ivar, AtomicHelperFn);
882     }
883     return;
884   }
885 
886   const ObjCPropertyDecl *prop = propImpl->getPropertyDecl();
887   QualType propType = prop->getType();
888   ObjCMethodDecl *getterMethod = prop->getGetterMethodDecl();
889 
890   ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
891 
892   // Pick an implementation strategy.
893   PropertyImplStrategy strategy(CGM, propImpl);
894   switch (strategy.getKind()) {
895   case PropertyImplStrategy::Native: {
896     // We don't need to do anything for a zero-size struct.
897     if (strategy.getIvarSize().isZero())
898       return;
899 
900     LValue LV = EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, 0);
901 
902     // Currently, all atomic accesses have to be through integer
903     // types, so there's no point in trying to pick a prettier type.
904     llvm::Type *bitcastType =
905       llvm::Type::getIntNTy(getLLVMContext(),
906                             getContext().toBits(strategy.getIvarSize()));
907     bitcastType = bitcastType->getPointerTo(); // addrspace 0 okay
908 
909     // Perform an atomic load.  This does not impose ordering constraints.
910     Address ivarAddr = LV.getAddress();
911     ivarAddr = Builder.CreateBitCast(ivarAddr, bitcastType);
912     llvm::LoadInst *load = Builder.CreateLoad(ivarAddr, "load");
913     load->setAtomic(llvm::Unordered);
914 
915     // Store that value into the return address.  Doing this with a
916     // bitcast is likely to produce some pretty ugly IR, but it's not
917     // the *most* terrible thing in the world.
918     Builder.CreateStore(load, Builder.CreateBitCast(ReturnValue, bitcastType));
919 
920     // Make sure we don't do an autorelease.
921     AutoreleaseResult = false;
922     return;
923   }
924 
925   case PropertyImplStrategy::GetSetProperty: {
926     llvm::Value *getPropertyFn =
927       CGM.getObjCRuntime().GetPropertyGetFunction();
928     if (!getPropertyFn) {
929       CGM.ErrorUnsupported(propImpl, "Obj-C getter requiring atomic copy");
930       return;
931     }
932 
933     // Return (ivar-type) objc_getProperty((id) self, _cmd, offset, true).
934     // FIXME: Can't this be simpler? This might even be worse than the
935     // corresponding gcc code.
936     llvm::Value *cmd =
937       Builder.CreateLoad(GetAddrOfLocalVar(getterMethod->getCmdDecl()), "cmd");
938     llvm::Value *self = Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
939     llvm::Value *ivarOffset =
940       EmitIvarOffset(classImpl->getClassInterface(), ivar);
941 
942     CallArgList args;
943     args.add(RValue::get(self), getContext().getObjCIdType());
944     args.add(RValue::get(cmd), getContext().getObjCSelType());
945     args.add(RValue::get(ivarOffset), getContext().getPointerDiffType());
946     args.add(RValue::get(Builder.getInt1(strategy.isAtomic())),
947              getContext().BoolTy);
948 
949     // FIXME: We shouldn't need to get the function info here, the
950     // runtime already should have computed it to build the function.
951     llvm::Instruction *CallInstruction;
952     RValue RV = EmitCall(
953         getTypes().arrangeFreeFunctionCall(
954             propType, args, FunctionType::ExtInfo(), RequiredArgs::All),
955         getPropertyFn, ReturnValueSlot(), args, CGCalleeInfo(),
956         &CallInstruction);
957     if (llvm::CallInst *call = dyn_cast<llvm::CallInst>(CallInstruction))
958       call->setTailCall();
959 
960     // We need to fix the type here. Ivars with copy & retain are
961     // always objects so we don't need to worry about complex or
962     // aggregates.
963     RV = RValue::get(Builder.CreateBitCast(
964         RV.getScalarVal(),
965         getTypes().ConvertType(getterMethod->getReturnType())));
966 
967     EmitReturnOfRValue(RV, propType);
968 
969     // objc_getProperty does an autorelease, so we should suppress ours.
970     AutoreleaseResult = false;
971 
972     return;
973   }
974 
975   case PropertyImplStrategy::CopyStruct:
976     emitStructGetterCall(*this, ivar, strategy.isAtomic(),
977                          strategy.hasStrongMember());
978     return;
979 
980   case PropertyImplStrategy::Expression:
981   case PropertyImplStrategy::SetPropertyAndExpressionGet: {
982     LValue LV = EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, 0);
983 
984     QualType ivarType = ivar->getType();
985     switch (getEvaluationKind(ivarType)) {
986     case TEK_Complex: {
987       ComplexPairTy pair = EmitLoadOfComplex(LV, SourceLocation());
988       EmitStoreOfComplex(pair, MakeAddrLValue(ReturnValue, ivarType),
989                          /*init*/ true);
990       return;
991     }
992     case TEK_Aggregate:
993       // The return value slot is guaranteed to not be aliased, but
994       // that's not necessarily the same as "on the stack", so
995       // we still potentially need objc_memmove_collectable.
996       EmitAggregateCopy(ReturnValue, LV.getAddress(), ivarType);
997       return;
998     case TEK_Scalar: {
999       llvm::Value *value;
1000       if (propType->isReferenceType()) {
1001         value = LV.getAddress().getPointer();
1002       } else {
1003         // We want to load and autoreleaseReturnValue ARC __weak ivars.
1004         if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak) {
1005           if (getLangOpts().ObjCAutoRefCount) {
1006             value = emitARCRetainLoadOfScalar(*this, LV, ivarType);
1007           } else {
1008             value = EmitARCLoadWeak(LV.getAddress());
1009           }
1010 
1011         // Otherwise we want to do a simple load, suppressing the
1012         // final autorelease.
1013         } else {
1014           value = EmitLoadOfLValue(LV, SourceLocation()).getScalarVal();
1015           AutoreleaseResult = false;
1016         }
1017 
1018         value = Builder.CreateBitCast(value, ConvertType(propType));
1019         value = Builder.CreateBitCast(
1020             value, ConvertType(GetterMethodDecl->getReturnType()));
1021       }
1022 
1023       EmitReturnOfRValue(RValue::get(value), propType);
1024       return;
1025     }
1026     }
1027     llvm_unreachable("bad evaluation kind");
1028   }
1029 
1030   }
1031   llvm_unreachable("bad @property implementation strategy!");
1032 }
1033 
1034 /// emitStructSetterCall - Call the runtime function to store the value
1035 /// from the first formal parameter into the given ivar.
emitStructSetterCall(CodeGenFunction & CGF,ObjCMethodDecl * OMD,ObjCIvarDecl * ivar)1036 static void emitStructSetterCall(CodeGenFunction &CGF, ObjCMethodDecl *OMD,
1037                                  ObjCIvarDecl *ivar) {
1038   // objc_copyStruct (&structIvar, &Arg,
1039   //                  sizeof (struct something), true, false);
1040   CallArgList args;
1041 
1042   // The first argument is the address of the ivar.
1043   llvm::Value *ivarAddr = CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(),
1044                                                 CGF.LoadObjCSelf(), ivar, 0)
1045     .getPointer();
1046   ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
1047   args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
1048 
1049   // The second argument is the address of the parameter variable.
1050   ParmVarDecl *argVar = *OMD->param_begin();
1051   DeclRefExpr argRef(argVar, false, argVar->getType().getNonReferenceType(),
1052                      VK_LValue, SourceLocation());
1053   llvm::Value *argAddr = CGF.EmitLValue(&argRef).getPointer();
1054   argAddr = CGF.Builder.CreateBitCast(argAddr, CGF.Int8PtrTy);
1055   args.add(RValue::get(argAddr), CGF.getContext().VoidPtrTy);
1056 
1057   // The third argument is the sizeof the type.
1058   llvm::Value *size =
1059     CGF.CGM.getSize(CGF.getContext().getTypeSizeInChars(ivar->getType()));
1060   args.add(RValue::get(size), CGF.getContext().getSizeType());
1061 
1062   // The fourth argument is the 'isAtomic' flag.
1063   args.add(RValue::get(CGF.Builder.getTrue()), CGF.getContext().BoolTy);
1064 
1065   // The fifth argument is the 'hasStrong' flag.
1066   // FIXME: should this really always be false?
1067   args.add(RValue::get(CGF.Builder.getFalse()), CGF.getContext().BoolTy);
1068 
1069   llvm::Value *copyStructFn = CGF.CGM.getObjCRuntime().GetSetStructFunction();
1070   CGF.EmitCall(CGF.getTypes().arrangeFreeFunctionCall(CGF.getContext().VoidTy,
1071                                                       args,
1072                                                       FunctionType::ExtInfo(),
1073                                                       RequiredArgs::All),
1074                copyStructFn, ReturnValueSlot(), args);
1075 }
1076 
1077 /// emitCPPObjectAtomicSetterCall - Call the runtime function to store
1078 /// the value from the first formal parameter into the given ivar, using
1079 /// the Cpp API for atomic Cpp objects with non-trivial copy assignment.
emitCPPObjectAtomicSetterCall(CodeGenFunction & CGF,ObjCMethodDecl * OMD,ObjCIvarDecl * ivar,llvm::Constant * AtomicHelperFn)1080 static void emitCPPObjectAtomicSetterCall(CodeGenFunction &CGF,
1081                                           ObjCMethodDecl *OMD,
1082                                           ObjCIvarDecl *ivar,
1083                                           llvm::Constant *AtomicHelperFn) {
1084   // objc_copyCppObjectAtomic (&CppObjectIvar, &Arg,
1085   //                           AtomicHelperFn);
1086   CallArgList args;
1087 
1088   // The first argument is the address of the ivar.
1089   llvm::Value *ivarAddr =
1090     CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(),
1091                           CGF.LoadObjCSelf(), ivar, 0).getPointer();
1092   ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
1093   args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
1094 
1095   // The second argument is the address of the parameter variable.
1096   ParmVarDecl *argVar = *OMD->param_begin();
1097   DeclRefExpr argRef(argVar, false, argVar->getType().getNonReferenceType(),
1098                      VK_LValue, SourceLocation());
1099   llvm::Value *argAddr = CGF.EmitLValue(&argRef).getPointer();
1100   argAddr = CGF.Builder.CreateBitCast(argAddr, CGF.Int8PtrTy);
1101   args.add(RValue::get(argAddr), CGF.getContext().VoidPtrTy);
1102 
1103   // Third argument is the helper function.
1104   args.add(RValue::get(AtomicHelperFn), CGF.getContext().VoidPtrTy);
1105 
1106   llvm::Value *copyCppAtomicObjectFn =
1107     CGF.CGM.getObjCRuntime().GetCppAtomicObjectSetFunction();
1108   CGF.EmitCall(CGF.getTypes().arrangeFreeFunctionCall(CGF.getContext().VoidTy,
1109                                                       args,
1110                                                       FunctionType::ExtInfo(),
1111                                                       RequiredArgs::All),
1112                copyCppAtomicObjectFn, ReturnValueSlot(), args);
1113 }
1114 
1115 
hasTrivialSetExpr(const ObjCPropertyImplDecl * PID)1116 static bool hasTrivialSetExpr(const ObjCPropertyImplDecl *PID) {
1117   Expr *setter = PID->getSetterCXXAssignment();
1118   if (!setter) return true;
1119 
1120   // Sema only makes only of these when the ivar has a C++ class type,
1121   // so the form is pretty constrained.
1122 
1123   // An operator call is trivial if the function it calls is trivial.
1124   // This also implies that there's nothing non-trivial going on with
1125   // the arguments, because operator= can only be trivial if it's a
1126   // synthesized assignment operator and therefore both parameters are
1127   // references.
1128   if (CallExpr *call = dyn_cast<CallExpr>(setter)) {
1129     if (const FunctionDecl *callee
1130           = dyn_cast_or_null<FunctionDecl>(call->getCalleeDecl()))
1131       if (callee->isTrivial())
1132         return true;
1133     return false;
1134   }
1135 
1136   assert(isa<ExprWithCleanups>(setter));
1137   return false;
1138 }
1139 
UseOptimizedSetter(CodeGenModule & CGM)1140 static bool UseOptimizedSetter(CodeGenModule &CGM) {
1141   if (CGM.getLangOpts().getGC() != LangOptions::NonGC)
1142     return false;
1143   return CGM.getLangOpts().ObjCRuntime.hasOptimizedSetter();
1144 }
1145 
1146 void
generateObjCSetterBody(const ObjCImplementationDecl * classImpl,const ObjCPropertyImplDecl * propImpl,llvm::Constant * AtomicHelperFn)1147 CodeGenFunction::generateObjCSetterBody(const ObjCImplementationDecl *classImpl,
1148                                         const ObjCPropertyImplDecl *propImpl,
1149                                         llvm::Constant *AtomicHelperFn) {
1150   const ObjCPropertyDecl *prop = propImpl->getPropertyDecl();
1151   ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
1152   ObjCMethodDecl *setterMethod = prop->getSetterMethodDecl();
1153 
1154   // Just use the setter expression if Sema gave us one and it's
1155   // non-trivial.
1156   if (!hasTrivialSetExpr(propImpl)) {
1157     if (!AtomicHelperFn)
1158       // If non-atomic, assignment is called directly.
1159       EmitStmt(propImpl->getSetterCXXAssignment());
1160     else
1161       // If atomic, assignment is called via a locking api.
1162       emitCPPObjectAtomicSetterCall(*this, setterMethod, ivar,
1163                                     AtomicHelperFn);
1164     return;
1165   }
1166 
1167   PropertyImplStrategy strategy(CGM, propImpl);
1168   switch (strategy.getKind()) {
1169   case PropertyImplStrategy::Native: {
1170     // We don't need to do anything for a zero-size struct.
1171     if (strategy.getIvarSize().isZero())
1172       return;
1173 
1174     Address argAddr = GetAddrOfLocalVar(*setterMethod->param_begin());
1175 
1176     LValue ivarLValue =
1177       EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, /*quals*/ 0);
1178     Address ivarAddr = ivarLValue.getAddress();
1179 
1180     // Currently, all atomic accesses have to be through integer
1181     // types, so there's no point in trying to pick a prettier type.
1182     llvm::Type *bitcastType =
1183       llvm::Type::getIntNTy(getLLVMContext(),
1184                             getContext().toBits(strategy.getIvarSize()));
1185 
1186     // Cast both arguments to the chosen operation type.
1187     argAddr = Builder.CreateElementBitCast(argAddr, bitcastType);
1188     ivarAddr = Builder.CreateElementBitCast(ivarAddr, bitcastType);
1189 
1190     // This bitcast load is likely to cause some nasty IR.
1191     llvm::Value *load = Builder.CreateLoad(argAddr);
1192 
1193     // Perform an atomic store.  There are no memory ordering requirements.
1194     llvm::StoreInst *store = Builder.CreateStore(load, ivarAddr);
1195     store->setAtomic(llvm::Unordered);
1196     return;
1197   }
1198 
1199   case PropertyImplStrategy::GetSetProperty:
1200   case PropertyImplStrategy::SetPropertyAndExpressionGet: {
1201 
1202     llvm::Value *setOptimizedPropertyFn = nullptr;
1203     llvm::Value *setPropertyFn = nullptr;
1204     if (UseOptimizedSetter(CGM)) {
1205       // 10.8 and iOS 6.0 code and GC is off
1206       setOptimizedPropertyFn =
1207         CGM.getObjCRuntime()
1208            .GetOptimizedPropertySetFunction(strategy.isAtomic(),
1209                                             strategy.isCopy());
1210       if (!setOptimizedPropertyFn) {
1211         CGM.ErrorUnsupported(propImpl, "Obj-C optimized setter - NYI");
1212         return;
1213       }
1214     }
1215     else {
1216       setPropertyFn = CGM.getObjCRuntime().GetPropertySetFunction();
1217       if (!setPropertyFn) {
1218         CGM.ErrorUnsupported(propImpl, "Obj-C setter requiring atomic copy");
1219         return;
1220       }
1221     }
1222 
1223     // Emit objc_setProperty((id) self, _cmd, offset, arg,
1224     //                       <is-atomic>, <is-copy>).
1225     llvm::Value *cmd =
1226       Builder.CreateLoad(GetAddrOfLocalVar(setterMethod->getCmdDecl()));
1227     llvm::Value *self =
1228       Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
1229     llvm::Value *ivarOffset =
1230       EmitIvarOffset(classImpl->getClassInterface(), ivar);
1231     Address argAddr = GetAddrOfLocalVar(*setterMethod->param_begin());
1232     llvm::Value *arg = Builder.CreateLoad(argAddr, "arg");
1233     arg = Builder.CreateBitCast(arg, VoidPtrTy);
1234 
1235     CallArgList args;
1236     args.add(RValue::get(self), getContext().getObjCIdType());
1237     args.add(RValue::get(cmd), getContext().getObjCSelType());
1238     if (setOptimizedPropertyFn) {
1239       args.add(RValue::get(arg), getContext().getObjCIdType());
1240       args.add(RValue::get(ivarOffset), getContext().getPointerDiffType());
1241       EmitCall(getTypes().arrangeFreeFunctionCall(getContext().VoidTy, args,
1242                                                   FunctionType::ExtInfo(),
1243                                                   RequiredArgs::All),
1244                setOptimizedPropertyFn, ReturnValueSlot(), args);
1245     } else {
1246       args.add(RValue::get(ivarOffset), getContext().getPointerDiffType());
1247       args.add(RValue::get(arg), getContext().getObjCIdType());
1248       args.add(RValue::get(Builder.getInt1(strategy.isAtomic())),
1249                getContext().BoolTy);
1250       args.add(RValue::get(Builder.getInt1(strategy.isCopy())),
1251                getContext().BoolTy);
1252       // FIXME: We shouldn't need to get the function info here, the runtime
1253       // already should have computed it to build the function.
1254       EmitCall(getTypes().arrangeFreeFunctionCall(getContext().VoidTy, args,
1255                                                   FunctionType::ExtInfo(),
1256                                                   RequiredArgs::All),
1257                setPropertyFn, ReturnValueSlot(), args);
1258     }
1259 
1260     return;
1261   }
1262 
1263   case PropertyImplStrategy::CopyStruct:
1264     emitStructSetterCall(*this, setterMethod, ivar);
1265     return;
1266 
1267   case PropertyImplStrategy::Expression:
1268     break;
1269   }
1270 
1271   // Otherwise, fake up some ASTs and emit a normal assignment.
1272   ValueDecl *selfDecl = setterMethod->getSelfDecl();
1273   DeclRefExpr self(selfDecl, false, selfDecl->getType(),
1274                    VK_LValue, SourceLocation());
1275   ImplicitCastExpr selfLoad(ImplicitCastExpr::OnStack,
1276                             selfDecl->getType(), CK_LValueToRValue, &self,
1277                             VK_RValue);
1278   ObjCIvarRefExpr ivarRef(ivar, ivar->getType().getNonReferenceType(),
1279                           SourceLocation(), SourceLocation(),
1280                           &selfLoad, true, true);
1281 
1282   ParmVarDecl *argDecl = *setterMethod->param_begin();
1283   QualType argType = argDecl->getType().getNonReferenceType();
1284   DeclRefExpr arg(argDecl, false, argType, VK_LValue, SourceLocation());
1285   ImplicitCastExpr argLoad(ImplicitCastExpr::OnStack,
1286                            argType.getUnqualifiedType(), CK_LValueToRValue,
1287                            &arg, VK_RValue);
1288 
1289   // The property type can differ from the ivar type in some situations with
1290   // Objective-C pointer types, we can always bit cast the RHS in these cases.
1291   // The following absurdity is just to ensure well-formed IR.
1292   CastKind argCK = CK_NoOp;
1293   if (ivarRef.getType()->isObjCObjectPointerType()) {
1294     if (argLoad.getType()->isObjCObjectPointerType())
1295       argCK = CK_BitCast;
1296     else if (argLoad.getType()->isBlockPointerType())
1297       argCK = CK_BlockPointerToObjCPointerCast;
1298     else
1299       argCK = CK_CPointerToObjCPointerCast;
1300   } else if (ivarRef.getType()->isBlockPointerType()) {
1301      if (argLoad.getType()->isBlockPointerType())
1302       argCK = CK_BitCast;
1303     else
1304       argCK = CK_AnyPointerToBlockPointerCast;
1305   } else if (ivarRef.getType()->isPointerType()) {
1306     argCK = CK_BitCast;
1307   }
1308   ImplicitCastExpr argCast(ImplicitCastExpr::OnStack,
1309                            ivarRef.getType(), argCK, &argLoad,
1310                            VK_RValue);
1311   Expr *finalArg = &argLoad;
1312   if (!getContext().hasSameUnqualifiedType(ivarRef.getType(),
1313                                            argLoad.getType()))
1314     finalArg = &argCast;
1315 
1316 
1317   BinaryOperator assign(&ivarRef, finalArg, BO_Assign,
1318                         ivarRef.getType(), VK_RValue, OK_Ordinary,
1319                         SourceLocation(), false);
1320   EmitStmt(&assign);
1321 }
1322 
1323 /// \brief Generate an Objective-C property setter function.
1324 ///
1325 /// The given Decl must be an ObjCImplementationDecl. \@synthesize
1326 /// is illegal within a category.
GenerateObjCSetter(ObjCImplementationDecl * IMP,const ObjCPropertyImplDecl * PID)1327 void CodeGenFunction::GenerateObjCSetter(ObjCImplementationDecl *IMP,
1328                                          const ObjCPropertyImplDecl *PID) {
1329   llvm::Constant *AtomicHelperFn =
1330       CodeGenFunction(CGM).GenerateObjCAtomicSetterCopyHelperFunction(PID);
1331   const ObjCPropertyDecl *PD = PID->getPropertyDecl();
1332   ObjCMethodDecl *OMD = PD->getSetterMethodDecl();
1333   assert(OMD && "Invalid call to generate setter (empty method)");
1334   StartObjCMethod(OMD, IMP->getClassInterface());
1335 
1336   generateObjCSetterBody(IMP, PID, AtomicHelperFn);
1337 
1338   FinishFunction();
1339 }
1340 
1341 namespace {
1342   struct DestroyIvar final : EHScopeStack::Cleanup {
1343   private:
1344     llvm::Value *addr;
1345     const ObjCIvarDecl *ivar;
1346     CodeGenFunction::Destroyer *destroyer;
1347     bool useEHCleanupForArray;
1348   public:
DestroyIvar__anon677e44b40311::DestroyIvar1349     DestroyIvar(llvm::Value *addr, const ObjCIvarDecl *ivar,
1350                 CodeGenFunction::Destroyer *destroyer,
1351                 bool useEHCleanupForArray)
1352       : addr(addr), ivar(ivar), destroyer(destroyer),
1353         useEHCleanupForArray(useEHCleanupForArray) {}
1354 
Emit__anon677e44b40311::DestroyIvar1355     void Emit(CodeGenFunction &CGF, Flags flags) override {
1356       LValue lvalue
1357         = CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), addr, ivar, /*CVR*/ 0);
1358       CGF.emitDestroy(lvalue.getAddress(), ivar->getType(), destroyer,
1359                       flags.isForNormalCleanup() && useEHCleanupForArray);
1360     }
1361   };
1362 }
1363 
1364 /// Like CodeGenFunction::destroyARCStrong, but do it with a call.
destroyARCStrongWithStore(CodeGenFunction & CGF,Address addr,QualType type)1365 static void destroyARCStrongWithStore(CodeGenFunction &CGF,
1366                                       Address addr,
1367                                       QualType type) {
1368   llvm::Value *null = getNullForVariable(addr);
1369   CGF.EmitARCStoreStrongCall(addr, null, /*ignored*/ true);
1370 }
1371 
emitCXXDestructMethod(CodeGenFunction & CGF,ObjCImplementationDecl * impl)1372 static void emitCXXDestructMethod(CodeGenFunction &CGF,
1373                                   ObjCImplementationDecl *impl) {
1374   CodeGenFunction::RunCleanupsScope scope(CGF);
1375 
1376   llvm::Value *self = CGF.LoadObjCSelf();
1377 
1378   const ObjCInterfaceDecl *iface = impl->getClassInterface();
1379   for (const ObjCIvarDecl *ivar = iface->all_declared_ivar_begin();
1380        ivar; ivar = ivar->getNextIvar()) {
1381     QualType type = ivar->getType();
1382 
1383     // Check whether the ivar is a destructible type.
1384     QualType::DestructionKind dtorKind = type.isDestructedType();
1385     if (!dtorKind) continue;
1386 
1387     CodeGenFunction::Destroyer *destroyer = nullptr;
1388 
1389     // Use a call to objc_storeStrong to destroy strong ivars, for the
1390     // general benefit of the tools.
1391     if (dtorKind == QualType::DK_objc_strong_lifetime) {
1392       destroyer = destroyARCStrongWithStore;
1393 
1394     // Otherwise use the default for the destruction kind.
1395     } else {
1396       destroyer = CGF.getDestroyer(dtorKind);
1397     }
1398 
1399     CleanupKind cleanupKind = CGF.getCleanupKind(dtorKind);
1400 
1401     CGF.EHStack.pushCleanup<DestroyIvar>(cleanupKind, self, ivar, destroyer,
1402                                          cleanupKind & EHCleanup);
1403   }
1404 
1405   assert(scope.requiresCleanups() && "nothing to do in .cxx_destruct?");
1406 }
1407 
GenerateObjCCtorDtorMethod(ObjCImplementationDecl * IMP,ObjCMethodDecl * MD,bool ctor)1408 void CodeGenFunction::GenerateObjCCtorDtorMethod(ObjCImplementationDecl *IMP,
1409                                                  ObjCMethodDecl *MD,
1410                                                  bool ctor) {
1411   MD->createImplicitParams(CGM.getContext(), IMP->getClassInterface());
1412   StartObjCMethod(MD, IMP->getClassInterface());
1413 
1414   // Emit .cxx_construct.
1415   if (ctor) {
1416     // Suppress the final autorelease in ARC.
1417     AutoreleaseResult = false;
1418 
1419     for (const auto *IvarInit : IMP->inits()) {
1420       FieldDecl *Field = IvarInit->getAnyMember();
1421       ObjCIvarDecl *Ivar = cast<ObjCIvarDecl>(Field);
1422       LValue LV = EmitLValueForIvar(TypeOfSelfObject(),
1423                                     LoadObjCSelf(), Ivar, 0);
1424       EmitAggExpr(IvarInit->getInit(),
1425                   AggValueSlot::forLValue(LV, AggValueSlot::IsDestructed,
1426                                           AggValueSlot::DoesNotNeedGCBarriers,
1427                                           AggValueSlot::IsNotAliased));
1428     }
1429     // constructor returns 'self'.
1430     CodeGenTypes &Types = CGM.getTypes();
1431     QualType IdTy(CGM.getContext().getObjCIdType());
1432     llvm::Value *SelfAsId =
1433       Builder.CreateBitCast(LoadObjCSelf(), Types.ConvertType(IdTy));
1434     EmitReturnOfRValue(RValue::get(SelfAsId), IdTy);
1435 
1436   // Emit .cxx_destruct.
1437   } else {
1438     emitCXXDestructMethod(*this, IMP);
1439   }
1440   FinishFunction();
1441 }
1442 
LoadObjCSelf()1443 llvm::Value *CodeGenFunction::LoadObjCSelf() {
1444   VarDecl *Self = cast<ObjCMethodDecl>(CurFuncDecl)->getSelfDecl();
1445   DeclRefExpr DRE(Self, /*is enclosing local*/ (CurFuncDecl != CurCodeDecl),
1446                   Self->getType(), VK_LValue, SourceLocation());
1447   return EmitLoadOfScalar(EmitDeclRefLValue(&DRE), SourceLocation());
1448 }
1449 
TypeOfSelfObject()1450 QualType CodeGenFunction::TypeOfSelfObject() {
1451   const ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(CurFuncDecl);
1452   ImplicitParamDecl *selfDecl = OMD->getSelfDecl();
1453   const ObjCObjectPointerType *PTy = cast<ObjCObjectPointerType>(
1454     getContext().getCanonicalType(selfDecl->getType()));
1455   return PTy->getPointeeType();
1456 }
1457 
EmitObjCForCollectionStmt(const ObjCForCollectionStmt & S)1458 void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
1459   llvm::Constant *EnumerationMutationFn =
1460     CGM.getObjCRuntime().EnumerationMutationFunction();
1461 
1462   if (!EnumerationMutationFn) {
1463     CGM.ErrorUnsupported(&S, "Obj-C fast enumeration for this runtime");
1464     return;
1465   }
1466 
1467   CGDebugInfo *DI = getDebugInfo();
1468   if (DI)
1469     DI->EmitLexicalBlockStart(Builder, S.getSourceRange().getBegin());
1470 
1471   // The local variable comes into scope immediately.
1472   AutoVarEmission variable = AutoVarEmission::invalid();
1473   if (const DeclStmt *SD = dyn_cast<DeclStmt>(S.getElement()))
1474     variable = EmitAutoVarAlloca(*cast<VarDecl>(SD->getSingleDecl()));
1475 
1476   JumpDest LoopEnd = getJumpDestInCurrentScope("forcoll.end");
1477 
1478   // Fast enumeration state.
1479   QualType StateTy = CGM.getObjCFastEnumerationStateType();
1480   Address StatePtr = CreateMemTemp(StateTy, "state.ptr");
1481   EmitNullInitialization(StatePtr, StateTy);
1482 
1483   // Number of elements in the items array.
1484   static const unsigned NumItems = 16;
1485 
1486   // Fetch the countByEnumeratingWithState:objects:count: selector.
1487   IdentifierInfo *II[] = {
1488     &CGM.getContext().Idents.get("countByEnumeratingWithState"),
1489     &CGM.getContext().Idents.get("objects"),
1490     &CGM.getContext().Idents.get("count")
1491   };
1492   Selector FastEnumSel =
1493     CGM.getContext().Selectors.getSelector(llvm::array_lengthof(II), &II[0]);
1494 
1495   QualType ItemsTy =
1496     getContext().getConstantArrayType(getContext().getObjCIdType(),
1497                                       llvm::APInt(32, NumItems),
1498                                       ArrayType::Normal, 0);
1499   Address ItemsPtr = CreateMemTemp(ItemsTy, "items.ptr");
1500 
1501   // Emit the collection pointer.  In ARC, we do a retain.
1502   llvm::Value *Collection;
1503   if (getLangOpts().ObjCAutoRefCount) {
1504     Collection = EmitARCRetainScalarExpr(S.getCollection());
1505 
1506     // Enter a cleanup to do the release.
1507     EmitObjCConsumeObject(S.getCollection()->getType(), Collection);
1508   } else {
1509     Collection = EmitScalarExpr(S.getCollection());
1510   }
1511 
1512   // The 'continue' label needs to appear within the cleanup for the
1513   // collection object.
1514   JumpDest AfterBody = getJumpDestInCurrentScope("forcoll.next");
1515 
1516   // Send it our message:
1517   CallArgList Args;
1518 
1519   // The first argument is a temporary of the enumeration-state type.
1520   Args.add(RValue::get(StatePtr.getPointer()),
1521            getContext().getPointerType(StateTy));
1522 
1523   // The second argument is a temporary array with space for NumItems
1524   // pointers.  We'll actually be loading elements from the array
1525   // pointer written into the control state; this buffer is so that
1526   // collections that *aren't* backed by arrays can still queue up
1527   // batches of elements.
1528   Args.add(RValue::get(ItemsPtr.getPointer()),
1529            getContext().getPointerType(ItemsTy));
1530 
1531   // The third argument is the capacity of that temporary array.
1532   llvm::Type *UnsignedLongLTy = ConvertType(getContext().UnsignedLongTy);
1533   llvm::Constant *Count = llvm::ConstantInt::get(UnsignedLongLTy, NumItems);
1534   Args.add(RValue::get(Count), getContext().UnsignedLongTy);
1535 
1536   // Start the enumeration.
1537   RValue CountRV =
1538     CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
1539                                              getContext().UnsignedLongTy,
1540                                              FastEnumSel,
1541                                              Collection, Args);
1542 
1543   // The initial number of objects that were returned in the buffer.
1544   llvm::Value *initialBufferLimit = CountRV.getScalarVal();
1545 
1546   llvm::BasicBlock *EmptyBB = createBasicBlock("forcoll.empty");
1547   llvm::BasicBlock *LoopInitBB = createBasicBlock("forcoll.loopinit");
1548 
1549   llvm::Value *zero = llvm::Constant::getNullValue(UnsignedLongLTy);
1550 
1551   // If the limit pointer was zero to begin with, the collection is
1552   // empty; skip all this. Set the branch weight assuming this has the same
1553   // probability of exiting the loop as any other loop exit.
1554   uint64_t EntryCount = getCurrentProfileCount();
1555   Builder.CreateCondBr(
1556       Builder.CreateICmpEQ(initialBufferLimit, zero, "iszero"), EmptyBB,
1557       LoopInitBB,
1558       createProfileWeights(EntryCount, getProfileCount(S.getBody())));
1559 
1560   // Otherwise, initialize the loop.
1561   EmitBlock(LoopInitBB);
1562 
1563   // Save the initial mutations value.  This is the value at an
1564   // address that was written into the state object by
1565   // countByEnumeratingWithState:objects:count:.
1566   Address StateMutationsPtrPtr = Builder.CreateStructGEP(
1567       StatePtr, 2, 2 * getPointerSize(), "mutationsptr.ptr");
1568   llvm::Value *StateMutationsPtr
1569     = Builder.CreateLoad(StateMutationsPtrPtr, "mutationsptr");
1570 
1571   llvm::Value *initialMutations =
1572     Builder.CreateAlignedLoad(StateMutationsPtr, getPointerAlign(),
1573                               "forcoll.initial-mutations");
1574 
1575   // Start looping.  This is the point we return to whenever we have a
1576   // fresh, non-empty batch of objects.
1577   llvm::BasicBlock *LoopBodyBB = createBasicBlock("forcoll.loopbody");
1578   EmitBlock(LoopBodyBB);
1579 
1580   // The current index into the buffer.
1581   llvm::PHINode *index = Builder.CreatePHI(UnsignedLongLTy, 3, "forcoll.index");
1582   index->addIncoming(zero, LoopInitBB);
1583 
1584   // The current buffer size.
1585   llvm::PHINode *count = Builder.CreatePHI(UnsignedLongLTy, 3, "forcoll.count");
1586   count->addIncoming(initialBufferLimit, LoopInitBB);
1587 
1588   incrementProfileCounter(&S);
1589 
1590   // Check whether the mutations value has changed from where it was
1591   // at start.  StateMutationsPtr should actually be invariant between
1592   // refreshes.
1593   StateMutationsPtr = Builder.CreateLoad(StateMutationsPtrPtr, "mutationsptr");
1594   llvm::Value *currentMutations
1595     = Builder.CreateAlignedLoad(StateMutationsPtr, getPointerAlign(),
1596                                 "statemutations");
1597 
1598   llvm::BasicBlock *WasMutatedBB = createBasicBlock("forcoll.mutated");
1599   llvm::BasicBlock *WasNotMutatedBB = createBasicBlock("forcoll.notmutated");
1600 
1601   Builder.CreateCondBr(Builder.CreateICmpEQ(currentMutations, initialMutations),
1602                        WasNotMutatedBB, WasMutatedBB);
1603 
1604   // If so, call the enumeration-mutation function.
1605   EmitBlock(WasMutatedBB);
1606   llvm::Value *V =
1607     Builder.CreateBitCast(Collection,
1608                           ConvertType(getContext().getObjCIdType()));
1609   CallArgList Args2;
1610   Args2.add(RValue::get(V), getContext().getObjCIdType());
1611   // FIXME: We shouldn't need to get the function info here, the runtime already
1612   // should have computed it to build the function.
1613   EmitCall(CGM.getTypes().arrangeFreeFunctionCall(getContext().VoidTy, Args2,
1614                                                   FunctionType::ExtInfo(),
1615                                                   RequiredArgs::All),
1616            EnumerationMutationFn, ReturnValueSlot(), Args2);
1617 
1618   // Otherwise, or if the mutation function returns, just continue.
1619   EmitBlock(WasNotMutatedBB);
1620 
1621   // Initialize the element variable.
1622   RunCleanupsScope elementVariableScope(*this);
1623   bool elementIsVariable;
1624   LValue elementLValue;
1625   QualType elementType;
1626   if (const DeclStmt *SD = dyn_cast<DeclStmt>(S.getElement())) {
1627     // Initialize the variable, in case it's a __block variable or something.
1628     EmitAutoVarInit(variable);
1629 
1630     const VarDecl* D = cast<VarDecl>(SD->getSingleDecl());
1631     DeclRefExpr tempDRE(const_cast<VarDecl*>(D), false, D->getType(),
1632                         VK_LValue, SourceLocation());
1633     elementLValue = EmitLValue(&tempDRE);
1634     elementType = D->getType();
1635     elementIsVariable = true;
1636 
1637     if (D->isARCPseudoStrong())
1638       elementLValue.getQuals().setObjCLifetime(Qualifiers::OCL_ExplicitNone);
1639   } else {
1640     elementLValue = LValue(); // suppress warning
1641     elementType = cast<Expr>(S.getElement())->getType();
1642     elementIsVariable = false;
1643   }
1644   llvm::Type *convertedElementType = ConvertType(elementType);
1645 
1646   // Fetch the buffer out of the enumeration state.
1647   // TODO: this pointer should actually be invariant between
1648   // refreshes, which would help us do certain loop optimizations.
1649   Address StateItemsPtr = Builder.CreateStructGEP(
1650       StatePtr, 1, getPointerSize(), "stateitems.ptr");
1651   llvm::Value *EnumStateItems =
1652     Builder.CreateLoad(StateItemsPtr, "stateitems");
1653 
1654   // Fetch the value at the current index from the buffer.
1655   llvm::Value *CurrentItemPtr =
1656     Builder.CreateGEP(EnumStateItems, index, "currentitem.ptr");
1657   llvm::Value *CurrentItem =
1658     Builder.CreateAlignedLoad(CurrentItemPtr, getPointerAlign());
1659 
1660   // Cast that value to the right type.
1661   CurrentItem = Builder.CreateBitCast(CurrentItem, convertedElementType,
1662                                       "currentitem");
1663 
1664   // Make sure we have an l-value.  Yes, this gets evaluated every
1665   // time through the loop.
1666   if (!elementIsVariable) {
1667     elementLValue = EmitLValue(cast<Expr>(S.getElement()));
1668     EmitStoreThroughLValue(RValue::get(CurrentItem), elementLValue);
1669   } else {
1670     EmitScalarInit(CurrentItem, elementLValue);
1671   }
1672 
1673   // If we do have an element variable, this assignment is the end of
1674   // its initialization.
1675   if (elementIsVariable)
1676     EmitAutoVarCleanups(variable);
1677 
1678   // Perform the loop body, setting up break and continue labels.
1679   BreakContinueStack.push_back(BreakContinue(LoopEnd, AfterBody));
1680   {
1681     RunCleanupsScope Scope(*this);
1682     EmitStmt(S.getBody());
1683   }
1684   BreakContinueStack.pop_back();
1685 
1686   // Destroy the element variable now.
1687   elementVariableScope.ForceCleanup();
1688 
1689   // Check whether there are more elements.
1690   EmitBlock(AfterBody.getBlock());
1691 
1692   llvm::BasicBlock *FetchMoreBB = createBasicBlock("forcoll.refetch");
1693 
1694   // First we check in the local buffer.
1695   llvm::Value *indexPlusOne
1696     = Builder.CreateAdd(index, llvm::ConstantInt::get(UnsignedLongLTy, 1));
1697 
1698   // If we haven't overrun the buffer yet, we can continue.
1699   // Set the branch weights based on the simplifying assumption that this is
1700   // like a while-loop, i.e., ignoring that the false branch fetches more
1701   // elements and then returns to the loop.
1702   Builder.CreateCondBr(
1703       Builder.CreateICmpULT(indexPlusOne, count), LoopBodyBB, FetchMoreBB,
1704       createProfileWeights(getProfileCount(S.getBody()), EntryCount));
1705 
1706   index->addIncoming(indexPlusOne, AfterBody.getBlock());
1707   count->addIncoming(count, AfterBody.getBlock());
1708 
1709   // Otherwise, we have to fetch more elements.
1710   EmitBlock(FetchMoreBB);
1711 
1712   CountRV =
1713     CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
1714                                              getContext().UnsignedLongTy,
1715                                              FastEnumSel,
1716                                              Collection, Args);
1717 
1718   // If we got a zero count, we're done.
1719   llvm::Value *refetchCount = CountRV.getScalarVal();
1720 
1721   // (note that the message send might split FetchMoreBB)
1722   index->addIncoming(zero, Builder.GetInsertBlock());
1723   count->addIncoming(refetchCount, Builder.GetInsertBlock());
1724 
1725   Builder.CreateCondBr(Builder.CreateICmpEQ(refetchCount, zero),
1726                        EmptyBB, LoopBodyBB);
1727 
1728   // No more elements.
1729   EmitBlock(EmptyBB);
1730 
1731   if (!elementIsVariable) {
1732     // If the element was not a declaration, set it to be null.
1733 
1734     llvm::Value *null = llvm::Constant::getNullValue(convertedElementType);
1735     elementLValue = EmitLValue(cast<Expr>(S.getElement()));
1736     EmitStoreThroughLValue(RValue::get(null), elementLValue);
1737   }
1738 
1739   if (DI)
1740     DI->EmitLexicalBlockEnd(Builder, S.getSourceRange().getEnd());
1741 
1742   // Leave the cleanup we entered in ARC.
1743   if (getLangOpts().ObjCAutoRefCount)
1744     PopCleanupBlock();
1745 
1746   EmitBlock(LoopEnd.getBlock());
1747 }
1748 
EmitObjCAtTryStmt(const ObjCAtTryStmt & S)1749 void CodeGenFunction::EmitObjCAtTryStmt(const ObjCAtTryStmt &S) {
1750   CGM.getObjCRuntime().EmitTryStmt(*this, S);
1751 }
1752 
EmitObjCAtThrowStmt(const ObjCAtThrowStmt & S)1753 void CodeGenFunction::EmitObjCAtThrowStmt(const ObjCAtThrowStmt &S) {
1754   CGM.getObjCRuntime().EmitThrowStmt(*this, S);
1755 }
1756 
EmitObjCAtSynchronizedStmt(const ObjCAtSynchronizedStmt & S)1757 void CodeGenFunction::EmitObjCAtSynchronizedStmt(
1758                                               const ObjCAtSynchronizedStmt &S) {
1759   CGM.getObjCRuntime().EmitSynchronizedStmt(*this, S);
1760 }
1761 
1762 namespace {
1763   struct CallObjCRelease final : EHScopeStack::Cleanup {
CallObjCRelease__anon677e44b40411::CallObjCRelease1764     CallObjCRelease(llvm::Value *object) : object(object) {}
1765     llvm::Value *object;
1766 
Emit__anon677e44b40411::CallObjCRelease1767     void Emit(CodeGenFunction &CGF, Flags flags) override {
1768       // Releases at the end of the full-expression are imprecise.
1769       CGF.EmitARCRelease(object, ARCImpreciseLifetime);
1770     }
1771   };
1772 }
1773 
1774 /// Produce the code for a CK_ARCConsumeObject.  Does a primitive
1775 /// release at the end of the full-expression.
EmitObjCConsumeObject(QualType type,llvm::Value * object)1776 llvm::Value *CodeGenFunction::EmitObjCConsumeObject(QualType type,
1777                                                     llvm::Value *object) {
1778   // If we're in a conditional branch, we need to make the cleanup
1779   // conditional.
1780   pushFullExprCleanup<CallObjCRelease>(getARCCleanupKind(), object);
1781   return object;
1782 }
1783 
EmitObjCExtendObjectLifetime(QualType type,llvm::Value * value)1784 llvm::Value *CodeGenFunction::EmitObjCExtendObjectLifetime(QualType type,
1785                                                            llvm::Value *value) {
1786   return EmitARCRetainAutorelease(type, value);
1787 }
1788 
1789 /// Given a number of pointers, inform the optimizer that they're
1790 /// being intrinsically used up until this point in the program.
EmitARCIntrinsicUse(ArrayRef<llvm::Value * > values)1791 void CodeGenFunction::EmitARCIntrinsicUse(ArrayRef<llvm::Value*> values) {
1792   llvm::Constant *&fn = CGM.getObjCEntrypoints().clang_arc_use;
1793   if (!fn) {
1794     llvm::FunctionType *fnType =
1795       llvm::FunctionType::get(CGM.VoidTy, None, true);
1796     fn = CGM.CreateRuntimeFunction(fnType, "clang.arc.use");
1797   }
1798 
1799   // This isn't really a "runtime" function, but as an intrinsic it
1800   // doesn't really matter as long as we align things up.
1801   EmitNounwindRuntimeCall(fn, values);
1802 }
1803 
1804 
createARCRuntimeFunction(CodeGenModule & CGM,llvm::FunctionType * type,StringRef fnName)1805 static llvm::Constant *createARCRuntimeFunction(CodeGenModule &CGM,
1806                                                 llvm::FunctionType *type,
1807                                                 StringRef fnName) {
1808   llvm::Constant *fn = CGM.CreateRuntimeFunction(type, fnName);
1809 
1810   if (llvm::Function *f = dyn_cast<llvm::Function>(fn)) {
1811     // If the target runtime doesn't naturally support ARC, emit weak
1812     // references to the runtime support library.  We don't really
1813     // permit this to fail, but we need a particular relocation style.
1814     if (!CGM.getLangOpts().ObjCRuntime.hasNativeARC()) {
1815       f->setLinkage(llvm::Function::ExternalWeakLinkage);
1816     } else if (fnName == "objc_retain" || fnName  == "objc_release") {
1817       // If we have Native ARC, set nonlazybind attribute for these APIs for
1818       // performance.
1819       f->addFnAttr(llvm::Attribute::NonLazyBind);
1820     }
1821   }
1822 
1823   return fn;
1824 }
1825 
1826 /// Perform an operation having the signature
1827 ///   i8* (i8*)
1828 /// where a null input causes a no-op and returns null.
emitARCValueOperation(CodeGenFunction & CGF,llvm::Value * value,llvm::Constant * & fn,StringRef fnName,bool isTailCall=false)1829 static llvm::Value *emitARCValueOperation(CodeGenFunction &CGF,
1830                                           llvm::Value *value,
1831                                           llvm::Constant *&fn,
1832                                           StringRef fnName,
1833                                           bool isTailCall = false) {
1834   if (isa<llvm::ConstantPointerNull>(value)) return value;
1835 
1836   if (!fn) {
1837     llvm::FunctionType *fnType =
1838       llvm::FunctionType::get(CGF.Int8PtrTy, CGF.Int8PtrTy, false);
1839     fn = createARCRuntimeFunction(CGF.CGM, fnType, fnName);
1840   }
1841 
1842   // Cast the argument to 'id'.
1843   llvm::Type *origType = value->getType();
1844   value = CGF.Builder.CreateBitCast(value, CGF.Int8PtrTy);
1845 
1846   // Call the function.
1847   llvm::CallInst *call = CGF.EmitNounwindRuntimeCall(fn, value);
1848   if (isTailCall)
1849     call->setTailCall();
1850 
1851   // Cast the result back to the original type.
1852   return CGF.Builder.CreateBitCast(call, origType);
1853 }
1854 
1855 /// Perform an operation having the following signature:
1856 ///   i8* (i8**)
emitARCLoadOperation(CodeGenFunction & CGF,Address addr,llvm::Constant * & fn,StringRef fnName)1857 static llvm::Value *emitARCLoadOperation(CodeGenFunction &CGF,
1858                                          Address addr,
1859                                          llvm::Constant *&fn,
1860                                          StringRef fnName) {
1861   if (!fn) {
1862     llvm::FunctionType *fnType =
1863       llvm::FunctionType::get(CGF.Int8PtrTy, CGF.Int8PtrPtrTy, false);
1864     fn = createARCRuntimeFunction(CGF.CGM, fnType, fnName);
1865   }
1866 
1867   // Cast the argument to 'id*'.
1868   llvm::Type *origType = addr.getElementType();
1869   addr = CGF.Builder.CreateBitCast(addr, CGF.Int8PtrPtrTy);
1870 
1871   // Call the function.
1872   llvm::Value *result = CGF.EmitNounwindRuntimeCall(fn, addr.getPointer());
1873 
1874   // Cast the result back to a dereference of the original type.
1875   if (origType != CGF.Int8PtrTy)
1876     result = CGF.Builder.CreateBitCast(result, origType);
1877 
1878   return result;
1879 }
1880 
1881 /// Perform an operation having the following signature:
1882 ///   i8* (i8**, i8*)
emitARCStoreOperation(CodeGenFunction & CGF,Address addr,llvm::Value * value,llvm::Constant * & fn,StringRef fnName,bool ignored)1883 static llvm::Value *emitARCStoreOperation(CodeGenFunction &CGF,
1884                                           Address addr,
1885                                           llvm::Value *value,
1886                                           llvm::Constant *&fn,
1887                                           StringRef fnName,
1888                                           bool ignored) {
1889   assert(addr.getElementType() == value->getType());
1890 
1891   if (!fn) {
1892     llvm::Type *argTypes[] = { CGF.Int8PtrPtrTy, CGF.Int8PtrTy };
1893 
1894     llvm::FunctionType *fnType
1895       = llvm::FunctionType::get(CGF.Int8PtrTy, argTypes, false);
1896     fn = createARCRuntimeFunction(CGF.CGM, fnType, fnName);
1897   }
1898 
1899   llvm::Type *origType = value->getType();
1900 
1901   llvm::Value *args[] = {
1902     CGF.Builder.CreateBitCast(addr.getPointer(), CGF.Int8PtrPtrTy),
1903     CGF.Builder.CreateBitCast(value, CGF.Int8PtrTy)
1904   };
1905   llvm::CallInst *result = CGF.EmitNounwindRuntimeCall(fn, args);
1906 
1907   if (ignored) return nullptr;
1908 
1909   return CGF.Builder.CreateBitCast(result, origType);
1910 }
1911 
1912 /// Perform an operation having the following signature:
1913 ///   void (i8**, i8**)
emitARCCopyOperation(CodeGenFunction & CGF,Address dst,Address src,llvm::Constant * & fn,StringRef fnName)1914 static void emitARCCopyOperation(CodeGenFunction &CGF,
1915                                  Address dst,
1916                                  Address src,
1917                                  llvm::Constant *&fn,
1918                                  StringRef fnName) {
1919   assert(dst.getType() == src.getType());
1920 
1921   if (!fn) {
1922     llvm::Type *argTypes[] = { CGF.Int8PtrPtrTy, CGF.Int8PtrPtrTy };
1923 
1924     llvm::FunctionType *fnType
1925       = llvm::FunctionType::get(CGF.Builder.getVoidTy(), argTypes, false);
1926     fn = createARCRuntimeFunction(CGF.CGM, fnType, fnName);
1927   }
1928 
1929   llvm::Value *args[] = {
1930     CGF.Builder.CreateBitCast(dst.getPointer(), CGF.Int8PtrPtrTy),
1931     CGF.Builder.CreateBitCast(src.getPointer(), CGF.Int8PtrPtrTy)
1932   };
1933   CGF.EmitNounwindRuntimeCall(fn, args);
1934 }
1935 
1936 /// Produce the code to do a retain.  Based on the type, calls one of:
1937 ///   call i8* \@objc_retain(i8* %value)
1938 ///   call i8* \@objc_retainBlock(i8* %value)
EmitARCRetain(QualType type,llvm::Value * value)1939 llvm::Value *CodeGenFunction::EmitARCRetain(QualType type, llvm::Value *value) {
1940   if (type->isBlockPointerType())
1941     return EmitARCRetainBlock(value, /*mandatory*/ false);
1942   else
1943     return EmitARCRetainNonBlock(value);
1944 }
1945 
1946 /// Retain the given object, with normal retain semantics.
1947 ///   call i8* \@objc_retain(i8* %value)
EmitARCRetainNonBlock(llvm::Value * value)1948 llvm::Value *CodeGenFunction::EmitARCRetainNonBlock(llvm::Value *value) {
1949   return emitARCValueOperation(*this, value,
1950                                CGM.getObjCEntrypoints().objc_retain,
1951                                "objc_retain");
1952 }
1953 
1954 /// Retain the given block, with _Block_copy semantics.
1955 ///   call i8* \@objc_retainBlock(i8* %value)
1956 ///
1957 /// \param mandatory - If false, emit the call with metadata
1958 /// indicating that it's okay for the optimizer to eliminate this call
1959 /// if it can prove that the block never escapes except down the stack.
EmitARCRetainBlock(llvm::Value * value,bool mandatory)1960 llvm::Value *CodeGenFunction::EmitARCRetainBlock(llvm::Value *value,
1961                                                  bool mandatory) {
1962   llvm::Value *result
1963     = emitARCValueOperation(*this, value,
1964                             CGM.getObjCEntrypoints().objc_retainBlock,
1965                             "objc_retainBlock");
1966 
1967   // If the copy isn't mandatory, add !clang.arc.copy_on_escape to
1968   // tell the optimizer that it doesn't need to do this copy if the
1969   // block doesn't escape, where being passed as an argument doesn't
1970   // count as escaping.
1971   if (!mandatory && isa<llvm::Instruction>(result)) {
1972     llvm::CallInst *call
1973       = cast<llvm::CallInst>(result->stripPointerCasts());
1974     assert(call->getCalledValue() == CGM.getObjCEntrypoints().objc_retainBlock);
1975 
1976     call->setMetadata("clang.arc.copy_on_escape",
1977                       llvm::MDNode::get(Builder.getContext(), None));
1978   }
1979 
1980   return result;
1981 }
1982 
1983 /// Retain the given object which is the result of a function call.
1984 ///   call i8* \@objc_retainAutoreleasedReturnValue(i8* %value)
1985 ///
1986 /// Yes, this function name is one character away from a different
1987 /// call with completely different semantics.
1988 llvm::Value *
EmitARCRetainAutoreleasedReturnValue(llvm::Value * value)1989 CodeGenFunction::EmitARCRetainAutoreleasedReturnValue(llvm::Value *value) {
1990   // Fetch the void(void) inline asm which marks that we're going to
1991   // retain the autoreleased return value.
1992   llvm::InlineAsm *&marker
1993     = CGM.getObjCEntrypoints().retainAutoreleasedReturnValueMarker;
1994   if (!marker) {
1995     StringRef assembly
1996       = CGM.getTargetCodeGenInfo()
1997            .getARCRetainAutoreleasedReturnValueMarker();
1998 
1999     // If we have an empty assembly string, there's nothing to do.
2000     if (assembly.empty()) {
2001 
2002     // Otherwise, at -O0, build an inline asm that we're going to call
2003     // in a moment.
2004     } else if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
2005       llvm::FunctionType *type =
2006         llvm::FunctionType::get(VoidTy, /*variadic*/false);
2007 
2008       marker = llvm::InlineAsm::get(type, assembly, "", /*sideeffects*/ true);
2009 
2010     // If we're at -O1 and above, we don't want to litter the code
2011     // with this marker yet, so leave a breadcrumb for the ARC
2012     // optimizer to pick up.
2013     } else {
2014       llvm::NamedMDNode *metadata =
2015         CGM.getModule().getOrInsertNamedMetadata(
2016                             "clang.arc.retainAutoreleasedReturnValueMarker");
2017       assert(metadata->getNumOperands() <= 1);
2018       if (metadata->getNumOperands() == 0) {
2019         metadata->addOperand(llvm::MDNode::get(
2020             getLLVMContext(), llvm::MDString::get(getLLVMContext(), assembly)));
2021       }
2022     }
2023   }
2024 
2025   // Call the marker asm if we made one, which we do only at -O0.
2026   if (marker)
2027     Builder.CreateCall(marker);
2028 
2029   return emitARCValueOperation(*this, value,
2030                      CGM.getObjCEntrypoints().objc_retainAutoreleasedReturnValue,
2031                                "objc_retainAutoreleasedReturnValue");
2032 }
2033 
2034 /// Release the given object.
2035 ///   call void \@objc_release(i8* %value)
EmitARCRelease(llvm::Value * value,ARCPreciseLifetime_t precise)2036 void CodeGenFunction::EmitARCRelease(llvm::Value *value,
2037                                      ARCPreciseLifetime_t precise) {
2038   if (isa<llvm::ConstantPointerNull>(value)) return;
2039 
2040   llvm::Constant *&fn = CGM.getObjCEntrypoints().objc_release;
2041   if (!fn) {
2042     llvm::FunctionType *fnType =
2043       llvm::FunctionType::get(Builder.getVoidTy(), Int8PtrTy, false);
2044     fn = createARCRuntimeFunction(CGM, fnType, "objc_release");
2045   }
2046 
2047   // Cast the argument to 'id'.
2048   value = Builder.CreateBitCast(value, Int8PtrTy);
2049 
2050   // Call objc_release.
2051   llvm::CallInst *call = EmitNounwindRuntimeCall(fn, value);
2052 
2053   if (precise == ARCImpreciseLifetime) {
2054     call->setMetadata("clang.imprecise_release",
2055                       llvm::MDNode::get(Builder.getContext(), None));
2056   }
2057 }
2058 
2059 /// Destroy a __strong variable.
2060 ///
2061 /// At -O0, emit a call to store 'null' into the address;
2062 /// instrumenting tools prefer this because the address is exposed,
2063 /// but it's relatively cumbersome to optimize.
2064 ///
2065 /// At -O1 and above, just load and call objc_release.
2066 ///
2067 ///   call void \@objc_storeStrong(i8** %addr, i8* null)
EmitARCDestroyStrong(Address addr,ARCPreciseLifetime_t precise)2068 void CodeGenFunction::EmitARCDestroyStrong(Address addr,
2069                                            ARCPreciseLifetime_t precise) {
2070   if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
2071     llvm::Value *null = getNullForVariable(addr);
2072     EmitARCStoreStrongCall(addr, null, /*ignored*/ true);
2073     return;
2074   }
2075 
2076   llvm::Value *value = Builder.CreateLoad(addr);
2077   EmitARCRelease(value, precise);
2078 }
2079 
2080 /// Store into a strong object.  Always calls this:
2081 ///   call void \@objc_storeStrong(i8** %addr, i8* %value)
EmitARCStoreStrongCall(Address addr,llvm::Value * value,bool ignored)2082 llvm::Value *CodeGenFunction::EmitARCStoreStrongCall(Address addr,
2083                                                      llvm::Value *value,
2084                                                      bool ignored) {
2085   assert(addr.getElementType() == value->getType());
2086 
2087   llvm::Constant *&fn = CGM.getObjCEntrypoints().objc_storeStrong;
2088   if (!fn) {
2089     llvm::Type *argTypes[] = { Int8PtrPtrTy, Int8PtrTy };
2090     llvm::FunctionType *fnType
2091       = llvm::FunctionType::get(Builder.getVoidTy(), argTypes, false);
2092     fn = createARCRuntimeFunction(CGM, fnType, "objc_storeStrong");
2093   }
2094 
2095   llvm::Value *args[] = {
2096     Builder.CreateBitCast(addr.getPointer(), Int8PtrPtrTy),
2097     Builder.CreateBitCast(value, Int8PtrTy)
2098   };
2099   EmitNounwindRuntimeCall(fn, args);
2100 
2101   if (ignored) return nullptr;
2102   return value;
2103 }
2104 
2105 /// Store into a strong object.  Sometimes calls this:
2106 ///   call void \@objc_storeStrong(i8** %addr, i8* %value)
2107 /// Other times, breaks it down into components.
EmitARCStoreStrong(LValue dst,llvm::Value * newValue,bool ignored)2108 llvm::Value *CodeGenFunction::EmitARCStoreStrong(LValue dst,
2109                                                  llvm::Value *newValue,
2110                                                  bool ignored) {
2111   QualType type = dst.getType();
2112   bool isBlock = type->isBlockPointerType();
2113 
2114   // Use a store barrier at -O0 unless this is a block type or the
2115   // lvalue is inadequately aligned.
2116   if (shouldUseFusedARCCalls() &&
2117       !isBlock &&
2118       (dst.getAlignment().isZero() ||
2119        dst.getAlignment() >= CharUnits::fromQuantity(PointerAlignInBytes))) {
2120     return EmitARCStoreStrongCall(dst.getAddress(), newValue, ignored);
2121   }
2122 
2123   // Otherwise, split it out.
2124 
2125   // Retain the new value.
2126   newValue = EmitARCRetain(type, newValue);
2127 
2128   // Read the old value.
2129   llvm::Value *oldValue = EmitLoadOfScalar(dst, SourceLocation());
2130 
2131   // Store.  We do this before the release so that any deallocs won't
2132   // see the old value.
2133   EmitStoreOfScalar(newValue, dst);
2134 
2135   // Finally, release the old value.
2136   EmitARCRelease(oldValue, dst.isARCPreciseLifetime());
2137 
2138   return newValue;
2139 }
2140 
2141 /// Autorelease the given object.
2142 ///   call i8* \@objc_autorelease(i8* %value)
EmitARCAutorelease(llvm::Value * value)2143 llvm::Value *CodeGenFunction::EmitARCAutorelease(llvm::Value *value) {
2144   return emitARCValueOperation(*this, value,
2145                                CGM.getObjCEntrypoints().objc_autorelease,
2146                                "objc_autorelease");
2147 }
2148 
2149 /// Autorelease the given object.
2150 ///   call i8* \@objc_autoreleaseReturnValue(i8* %value)
2151 llvm::Value *
EmitARCAutoreleaseReturnValue(llvm::Value * value)2152 CodeGenFunction::EmitARCAutoreleaseReturnValue(llvm::Value *value) {
2153   return emitARCValueOperation(*this, value,
2154                             CGM.getObjCEntrypoints().objc_autoreleaseReturnValue,
2155                                "objc_autoreleaseReturnValue",
2156                                /*isTailCall*/ true);
2157 }
2158 
2159 /// Do a fused retain/autorelease of the given object.
2160 ///   call i8* \@objc_retainAutoreleaseReturnValue(i8* %value)
2161 llvm::Value *
EmitARCRetainAutoreleaseReturnValue(llvm::Value * value)2162 CodeGenFunction::EmitARCRetainAutoreleaseReturnValue(llvm::Value *value) {
2163   return emitARCValueOperation(*this, value,
2164                      CGM.getObjCEntrypoints().objc_retainAutoreleaseReturnValue,
2165                                "objc_retainAutoreleaseReturnValue",
2166                                /*isTailCall*/ true);
2167 }
2168 
2169 /// Do a fused retain/autorelease of the given object.
2170 ///   call i8* \@objc_retainAutorelease(i8* %value)
2171 /// or
2172 ///   %retain = call i8* \@objc_retainBlock(i8* %value)
2173 ///   call i8* \@objc_autorelease(i8* %retain)
EmitARCRetainAutorelease(QualType type,llvm::Value * value)2174 llvm::Value *CodeGenFunction::EmitARCRetainAutorelease(QualType type,
2175                                                        llvm::Value *value) {
2176   if (!type->isBlockPointerType())
2177     return EmitARCRetainAutoreleaseNonBlock(value);
2178 
2179   if (isa<llvm::ConstantPointerNull>(value)) return value;
2180 
2181   llvm::Type *origType = value->getType();
2182   value = Builder.CreateBitCast(value, Int8PtrTy);
2183   value = EmitARCRetainBlock(value, /*mandatory*/ true);
2184   value = EmitARCAutorelease(value);
2185   return Builder.CreateBitCast(value, origType);
2186 }
2187 
2188 /// Do a fused retain/autorelease of the given object.
2189 ///   call i8* \@objc_retainAutorelease(i8* %value)
2190 llvm::Value *
EmitARCRetainAutoreleaseNonBlock(llvm::Value * value)2191 CodeGenFunction::EmitARCRetainAutoreleaseNonBlock(llvm::Value *value) {
2192   return emitARCValueOperation(*this, value,
2193                                CGM.getObjCEntrypoints().objc_retainAutorelease,
2194                                "objc_retainAutorelease");
2195 }
2196 
2197 /// i8* \@objc_loadWeak(i8** %addr)
2198 /// Essentially objc_autorelease(objc_loadWeakRetained(addr)).
EmitARCLoadWeak(Address addr)2199 llvm::Value *CodeGenFunction::EmitARCLoadWeak(Address addr) {
2200   return emitARCLoadOperation(*this, addr,
2201                               CGM.getObjCEntrypoints().objc_loadWeak,
2202                               "objc_loadWeak");
2203 }
2204 
2205 /// i8* \@objc_loadWeakRetained(i8** %addr)
EmitARCLoadWeakRetained(Address addr)2206 llvm::Value *CodeGenFunction::EmitARCLoadWeakRetained(Address addr) {
2207   return emitARCLoadOperation(*this, addr,
2208                               CGM.getObjCEntrypoints().objc_loadWeakRetained,
2209                               "objc_loadWeakRetained");
2210 }
2211 
2212 /// i8* \@objc_storeWeak(i8** %addr, i8* %value)
2213 /// Returns %value.
EmitARCStoreWeak(Address addr,llvm::Value * value,bool ignored)2214 llvm::Value *CodeGenFunction::EmitARCStoreWeak(Address addr,
2215                                                llvm::Value *value,
2216                                                bool ignored) {
2217   return emitARCStoreOperation(*this, addr, value,
2218                                CGM.getObjCEntrypoints().objc_storeWeak,
2219                                "objc_storeWeak", ignored);
2220 }
2221 
2222 /// i8* \@objc_initWeak(i8** %addr, i8* %value)
2223 /// Returns %value.  %addr is known to not have a current weak entry.
2224 /// Essentially equivalent to:
2225 ///   *addr = nil; objc_storeWeak(addr, value);
EmitARCInitWeak(Address addr,llvm::Value * value)2226 void CodeGenFunction::EmitARCInitWeak(Address addr, llvm::Value *value) {
2227   // If we're initializing to null, just write null to memory; no need
2228   // to get the runtime involved.  But don't do this if optimization
2229   // is enabled, because accounting for this would make the optimizer
2230   // much more complicated.
2231   if (isa<llvm::ConstantPointerNull>(value) &&
2232       CGM.getCodeGenOpts().OptimizationLevel == 0) {
2233     Builder.CreateStore(value, addr);
2234     return;
2235   }
2236 
2237   emitARCStoreOperation(*this, addr, value,
2238                         CGM.getObjCEntrypoints().objc_initWeak,
2239                         "objc_initWeak", /*ignored*/ true);
2240 }
2241 
2242 /// void \@objc_destroyWeak(i8** %addr)
2243 /// Essentially objc_storeWeak(addr, nil).
EmitARCDestroyWeak(Address addr)2244 void CodeGenFunction::EmitARCDestroyWeak(Address addr) {
2245   llvm::Constant *&fn = CGM.getObjCEntrypoints().objc_destroyWeak;
2246   if (!fn) {
2247     llvm::FunctionType *fnType =
2248       llvm::FunctionType::get(Builder.getVoidTy(), Int8PtrPtrTy, false);
2249     fn = createARCRuntimeFunction(CGM, fnType, "objc_destroyWeak");
2250   }
2251 
2252   // Cast the argument to 'id*'.
2253   addr = Builder.CreateBitCast(addr, Int8PtrPtrTy);
2254 
2255   EmitNounwindRuntimeCall(fn, addr.getPointer());
2256 }
2257 
2258 /// void \@objc_moveWeak(i8** %dest, i8** %src)
2259 /// Disregards the current value in %dest.  Leaves %src pointing to nothing.
2260 /// Essentially (objc_copyWeak(dest, src), objc_destroyWeak(src)).
EmitARCMoveWeak(Address dst,Address src)2261 void CodeGenFunction::EmitARCMoveWeak(Address dst, Address src) {
2262   emitARCCopyOperation(*this, dst, src,
2263                        CGM.getObjCEntrypoints().objc_moveWeak,
2264                        "objc_moveWeak");
2265 }
2266 
2267 /// void \@objc_copyWeak(i8** %dest, i8** %src)
2268 /// Disregards the current value in %dest.  Essentially
2269 ///   objc_release(objc_initWeak(dest, objc_readWeakRetained(src)))
EmitARCCopyWeak(Address dst,Address src)2270 void CodeGenFunction::EmitARCCopyWeak(Address dst, Address src) {
2271   emitARCCopyOperation(*this, dst, src,
2272                        CGM.getObjCEntrypoints().objc_copyWeak,
2273                        "objc_copyWeak");
2274 }
2275 
2276 /// Produce the code to do a objc_autoreleasepool_push.
2277 ///   call i8* \@objc_autoreleasePoolPush(void)
EmitObjCAutoreleasePoolPush()2278 llvm::Value *CodeGenFunction::EmitObjCAutoreleasePoolPush() {
2279   llvm::Constant *&fn = CGM.getObjCEntrypoints().objc_autoreleasePoolPush;
2280   if (!fn) {
2281     llvm::FunctionType *fnType =
2282       llvm::FunctionType::get(Int8PtrTy, false);
2283     fn = createARCRuntimeFunction(CGM, fnType, "objc_autoreleasePoolPush");
2284   }
2285 
2286   return EmitNounwindRuntimeCall(fn);
2287 }
2288 
2289 /// Produce the code to do a primitive release.
2290 ///   call void \@objc_autoreleasePoolPop(i8* %ptr)
EmitObjCAutoreleasePoolPop(llvm::Value * value)2291 void CodeGenFunction::EmitObjCAutoreleasePoolPop(llvm::Value *value) {
2292   assert(value->getType() == Int8PtrTy);
2293 
2294   llvm::Constant *&fn = CGM.getObjCEntrypoints().objc_autoreleasePoolPop;
2295   if (!fn) {
2296     llvm::FunctionType *fnType =
2297       llvm::FunctionType::get(Builder.getVoidTy(), Int8PtrTy, false);
2298 
2299     // We don't want to use a weak import here; instead we should not
2300     // fall into this path.
2301     fn = createARCRuntimeFunction(CGM, fnType, "objc_autoreleasePoolPop");
2302   }
2303 
2304   // objc_autoreleasePoolPop can throw.
2305   EmitRuntimeCallOrInvoke(fn, value);
2306 }
2307 
2308 /// Produce the code to do an MRR version objc_autoreleasepool_push.
2309 /// Which is: [[NSAutoreleasePool alloc] init];
2310 /// Where alloc is declared as: + (id) alloc; in NSAutoreleasePool class.
2311 /// init is declared as: - (id) init; in its NSObject super class.
2312 ///
EmitObjCMRRAutoreleasePoolPush()2313 llvm::Value *CodeGenFunction::EmitObjCMRRAutoreleasePoolPush() {
2314   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
2315   llvm::Value *Receiver = Runtime.EmitNSAutoreleasePoolClassRef(*this);
2316   // [NSAutoreleasePool alloc]
2317   IdentifierInfo *II = &CGM.getContext().Idents.get("alloc");
2318   Selector AllocSel = getContext().Selectors.getSelector(0, &II);
2319   CallArgList Args;
2320   RValue AllocRV =
2321     Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
2322                                 getContext().getObjCIdType(),
2323                                 AllocSel, Receiver, Args);
2324 
2325   // [Receiver init]
2326   Receiver = AllocRV.getScalarVal();
2327   II = &CGM.getContext().Idents.get("init");
2328   Selector InitSel = getContext().Selectors.getSelector(0, &II);
2329   RValue InitRV =
2330     Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
2331                                 getContext().getObjCIdType(),
2332                                 InitSel, Receiver, Args);
2333   return InitRV.getScalarVal();
2334 }
2335 
2336 /// Produce the code to do a primitive release.
2337 /// [tmp drain];
EmitObjCMRRAutoreleasePoolPop(llvm::Value * Arg)2338 void CodeGenFunction::EmitObjCMRRAutoreleasePoolPop(llvm::Value *Arg) {
2339   IdentifierInfo *II = &CGM.getContext().Idents.get("drain");
2340   Selector DrainSel = getContext().Selectors.getSelector(0, &II);
2341   CallArgList Args;
2342   CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
2343                               getContext().VoidTy, DrainSel, Arg, Args);
2344 }
2345 
destroyARCStrongPrecise(CodeGenFunction & CGF,Address addr,QualType type)2346 void CodeGenFunction::destroyARCStrongPrecise(CodeGenFunction &CGF,
2347                                               Address addr,
2348                                               QualType type) {
2349   CGF.EmitARCDestroyStrong(addr, ARCPreciseLifetime);
2350 }
2351 
destroyARCStrongImprecise(CodeGenFunction & CGF,Address addr,QualType type)2352 void CodeGenFunction::destroyARCStrongImprecise(CodeGenFunction &CGF,
2353                                                 Address addr,
2354                                                 QualType type) {
2355   CGF.EmitARCDestroyStrong(addr, ARCImpreciseLifetime);
2356 }
2357 
destroyARCWeak(CodeGenFunction & CGF,Address addr,QualType type)2358 void CodeGenFunction::destroyARCWeak(CodeGenFunction &CGF,
2359                                      Address addr,
2360                                      QualType type) {
2361   CGF.EmitARCDestroyWeak(addr);
2362 }
2363 
2364 namespace {
2365   struct CallObjCAutoreleasePoolObject final : EHScopeStack::Cleanup {
2366     llvm::Value *Token;
2367 
CallObjCAutoreleasePoolObject__anon677e44b40511::CallObjCAutoreleasePoolObject2368     CallObjCAutoreleasePoolObject(llvm::Value *token) : Token(token) {}
2369 
Emit__anon677e44b40511::CallObjCAutoreleasePoolObject2370     void Emit(CodeGenFunction &CGF, Flags flags) override {
2371       CGF.EmitObjCAutoreleasePoolPop(Token);
2372     }
2373   };
2374   struct CallObjCMRRAutoreleasePoolObject final : EHScopeStack::Cleanup {
2375     llvm::Value *Token;
2376 
CallObjCMRRAutoreleasePoolObject__anon677e44b40511::CallObjCMRRAutoreleasePoolObject2377     CallObjCMRRAutoreleasePoolObject(llvm::Value *token) : Token(token) {}
2378 
Emit__anon677e44b40511::CallObjCMRRAutoreleasePoolObject2379     void Emit(CodeGenFunction &CGF, Flags flags) override {
2380       CGF.EmitObjCMRRAutoreleasePoolPop(Token);
2381     }
2382   };
2383 }
2384 
EmitObjCAutoreleasePoolCleanup(llvm::Value * Ptr)2385 void CodeGenFunction::EmitObjCAutoreleasePoolCleanup(llvm::Value *Ptr) {
2386   if (CGM.getLangOpts().ObjCAutoRefCount)
2387     EHStack.pushCleanup<CallObjCAutoreleasePoolObject>(NormalCleanup, Ptr);
2388   else
2389     EHStack.pushCleanup<CallObjCMRRAutoreleasePoolObject>(NormalCleanup, Ptr);
2390 }
2391 
tryEmitARCRetainLoadOfScalar(CodeGenFunction & CGF,LValue lvalue,QualType type)2392 static TryEmitResult tryEmitARCRetainLoadOfScalar(CodeGenFunction &CGF,
2393                                                   LValue lvalue,
2394                                                   QualType type) {
2395   switch (type.getObjCLifetime()) {
2396   case Qualifiers::OCL_None:
2397   case Qualifiers::OCL_ExplicitNone:
2398   case Qualifiers::OCL_Strong:
2399   case Qualifiers::OCL_Autoreleasing:
2400     return TryEmitResult(CGF.EmitLoadOfLValue(lvalue,
2401                                               SourceLocation()).getScalarVal(),
2402                          false);
2403 
2404   case Qualifiers::OCL_Weak:
2405     return TryEmitResult(CGF.EmitARCLoadWeakRetained(lvalue.getAddress()),
2406                          true);
2407   }
2408 
2409   llvm_unreachable("impossible lifetime!");
2410 }
2411 
tryEmitARCRetainLoadOfScalar(CodeGenFunction & CGF,const Expr * e)2412 static TryEmitResult tryEmitARCRetainLoadOfScalar(CodeGenFunction &CGF,
2413                                                   const Expr *e) {
2414   e = e->IgnoreParens();
2415   QualType type = e->getType();
2416 
2417   // If we're loading retained from a __strong xvalue, we can avoid
2418   // an extra retain/release pair by zeroing out the source of this
2419   // "move" operation.
2420   if (e->isXValue() &&
2421       !type.isConstQualified() &&
2422       type.getObjCLifetime() == Qualifiers::OCL_Strong) {
2423     // Emit the lvalue.
2424     LValue lv = CGF.EmitLValue(e);
2425 
2426     // Load the object pointer.
2427     llvm::Value *result = CGF.EmitLoadOfLValue(lv,
2428                                                SourceLocation()).getScalarVal();
2429 
2430     // Set the source pointer to NULL.
2431     CGF.EmitStoreOfScalar(getNullForVariable(lv.getAddress()), lv);
2432 
2433     return TryEmitResult(result, true);
2434   }
2435 
2436   // As a very special optimization, in ARC++, if the l-value is the
2437   // result of a non-volatile assignment, do a simple retain of the
2438   // result of the call to objc_storeWeak instead of reloading.
2439   if (CGF.getLangOpts().CPlusPlus &&
2440       !type.isVolatileQualified() &&
2441       type.getObjCLifetime() == Qualifiers::OCL_Weak &&
2442       isa<BinaryOperator>(e) &&
2443       cast<BinaryOperator>(e)->getOpcode() == BO_Assign)
2444     return TryEmitResult(CGF.EmitScalarExpr(e), false);
2445 
2446   return tryEmitARCRetainLoadOfScalar(CGF, CGF.EmitLValue(e), type);
2447 }
2448 
2449 static llvm::Value *emitARCRetainAfterCall(CodeGenFunction &CGF,
2450                                            llvm::Value *value);
2451 
2452 /// Given that the given expression is some sort of call (which does
2453 /// not return retained), emit a retain following it.
emitARCRetainCall(CodeGenFunction & CGF,const Expr * e)2454 static llvm::Value *emitARCRetainCall(CodeGenFunction &CGF, const Expr *e) {
2455   llvm::Value *value = CGF.EmitScalarExpr(e);
2456   return emitARCRetainAfterCall(CGF, value);
2457 }
2458 
emitARCRetainAfterCall(CodeGenFunction & CGF,llvm::Value * value)2459 static llvm::Value *emitARCRetainAfterCall(CodeGenFunction &CGF,
2460                                            llvm::Value *value) {
2461   if (llvm::CallInst *call = dyn_cast<llvm::CallInst>(value)) {
2462     CGBuilderTy::InsertPoint ip = CGF.Builder.saveIP();
2463 
2464     // Place the retain immediately following the call.
2465     CGF.Builder.SetInsertPoint(call->getParent(),
2466                                ++llvm::BasicBlock::iterator(call));
2467     value = CGF.EmitARCRetainAutoreleasedReturnValue(value);
2468 
2469     CGF.Builder.restoreIP(ip);
2470     return value;
2471   } else if (llvm::InvokeInst *invoke = dyn_cast<llvm::InvokeInst>(value)) {
2472     CGBuilderTy::InsertPoint ip = CGF.Builder.saveIP();
2473 
2474     // Place the retain at the beginning of the normal destination block.
2475     llvm::BasicBlock *BB = invoke->getNormalDest();
2476     CGF.Builder.SetInsertPoint(BB, BB->begin());
2477     value = CGF.EmitARCRetainAutoreleasedReturnValue(value);
2478 
2479     CGF.Builder.restoreIP(ip);
2480     return value;
2481 
2482   // Bitcasts can arise because of related-result returns.  Rewrite
2483   // the operand.
2484   } else if (llvm::BitCastInst *bitcast = dyn_cast<llvm::BitCastInst>(value)) {
2485     llvm::Value *operand = bitcast->getOperand(0);
2486     operand = emitARCRetainAfterCall(CGF, operand);
2487     bitcast->setOperand(0, operand);
2488     return bitcast;
2489 
2490   // Generic fall-back case.
2491   } else {
2492     // Retain using the non-block variant: we never need to do a copy
2493     // of a block that's been returned to us.
2494     return CGF.EmitARCRetainNonBlock(value);
2495   }
2496 }
2497 
2498 /// Determine whether it might be important to emit a separate
2499 /// objc_retain_block on the result of the given expression, or
2500 /// whether it's okay to just emit it in a +1 context.
shouldEmitSeparateBlockRetain(const Expr * e)2501 static bool shouldEmitSeparateBlockRetain(const Expr *e) {
2502   assert(e->getType()->isBlockPointerType());
2503   e = e->IgnoreParens();
2504 
2505   // For future goodness, emit block expressions directly in +1
2506   // contexts if we can.
2507   if (isa<BlockExpr>(e))
2508     return false;
2509 
2510   if (const CastExpr *cast = dyn_cast<CastExpr>(e)) {
2511     switch (cast->getCastKind()) {
2512     // Emitting these operations in +1 contexts is goodness.
2513     case CK_LValueToRValue:
2514     case CK_ARCReclaimReturnedObject:
2515     case CK_ARCConsumeObject:
2516     case CK_ARCProduceObject:
2517       return false;
2518 
2519     // These operations preserve a block type.
2520     case CK_NoOp:
2521     case CK_BitCast:
2522       return shouldEmitSeparateBlockRetain(cast->getSubExpr());
2523 
2524     // These operations are known to be bad (or haven't been considered).
2525     case CK_AnyPointerToBlockPointerCast:
2526     default:
2527       return true;
2528     }
2529   }
2530 
2531   return true;
2532 }
2533 
2534 /// Try to emit a PseudoObjectExpr at +1.
2535 ///
2536 /// This massively duplicates emitPseudoObjectRValue.
tryEmitARCRetainPseudoObject(CodeGenFunction & CGF,const PseudoObjectExpr * E)2537 static TryEmitResult tryEmitARCRetainPseudoObject(CodeGenFunction &CGF,
2538                                                   const PseudoObjectExpr *E) {
2539   SmallVector<CodeGenFunction::OpaqueValueMappingData, 4> opaques;
2540 
2541   // Find the result expression.
2542   const Expr *resultExpr = E->getResultExpr();
2543   assert(resultExpr);
2544   TryEmitResult result;
2545 
2546   for (PseudoObjectExpr::const_semantics_iterator
2547          i = E->semantics_begin(), e = E->semantics_end(); i != e; ++i) {
2548     const Expr *semantic = *i;
2549 
2550     // If this semantic expression is an opaque value, bind it
2551     // to the result of its source expression.
2552     if (const OpaqueValueExpr *ov = dyn_cast<OpaqueValueExpr>(semantic)) {
2553       typedef CodeGenFunction::OpaqueValueMappingData OVMA;
2554       OVMA opaqueData;
2555 
2556       // If this semantic is the result of the pseudo-object
2557       // expression, try to evaluate the source as +1.
2558       if (ov == resultExpr) {
2559         assert(!OVMA::shouldBindAsLValue(ov));
2560         result = tryEmitARCRetainScalarExpr(CGF, ov->getSourceExpr());
2561         opaqueData = OVMA::bind(CGF, ov, RValue::get(result.getPointer()));
2562 
2563       // Otherwise, just bind it.
2564       } else {
2565         opaqueData = OVMA::bind(CGF, ov, ov->getSourceExpr());
2566       }
2567       opaques.push_back(opaqueData);
2568 
2569     // Otherwise, if the expression is the result, evaluate it
2570     // and remember the result.
2571     } else if (semantic == resultExpr) {
2572       result = tryEmitARCRetainScalarExpr(CGF, semantic);
2573 
2574     // Otherwise, evaluate the expression in an ignored context.
2575     } else {
2576       CGF.EmitIgnoredExpr(semantic);
2577     }
2578   }
2579 
2580   // Unbind all the opaques now.
2581   for (unsigned i = 0, e = opaques.size(); i != e; ++i)
2582     opaques[i].unbind(CGF);
2583 
2584   return result;
2585 }
2586 
2587 static TryEmitResult
tryEmitARCRetainScalarExpr(CodeGenFunction & CGF,const Expr * e)2588 tryEmitARCRetainScalarExpr(CodeGenFunction &CGF, const Expr *e) {
2589   // We should *never* see a nested full-expression here, because if
2590   // we fail to emit at +1, our caller must not retain after we close
2591   // out the full-expression.
2592   assert(!isa<ExprWithCleanups>(e));
2593 
2594   // The desired result type, if it differs from the type of the
2595   // ultimate opaque expression.
2596   llvm::Type *resultType = nullptr;
2597 
2598   while (true) {
2599     e = e->IgnoreParens();
2600 
2601     // There's a break at the end of this if-chain;  anything
2602     // that wants to keep looping has to explicitly continue.
2603     if (const CastExpr *ce = dyn_cast<CastExpr>(e)) {
2604       switch (ce->getCastKind()) {
2605       // No-op casts don't change the type, so we just ignore them.
2606       case CK_NoOp:
2607         e = ce->getSubExpr();
2608         continue;
2609 
2610       case CK_LValueToRValue: {
2611         TryEmitResult loadResult
2612           = tryEmitARCRetainLoadOfScalar(CGF, ce->getSubExpr());
2613         if (resultType) {
2614           llvm::Value *value = loadResult.getPointer();
2615           value = CGF.Builder.CreateBitCast(value, resultType);
2616           loadResult.setPointer(value);
2617         }
2618         return loadResult;
2619       }
2620 
2621       // These casts can change the type, so remember that and
2622       // soldier on.  We only need to remember the outermost such
2623       // cast, though.
2624       case CK_CPointerToObjCPointerCast:
2625       case CK_BlockPointerToObjCPointerCast:
2626       case CK_AnyPointerToBlockPointerCast:
2627       case CK_BitCast:
2628         if (!resultType)
2629           resultType = CGF.ConvertType(ce->getType());
2630         e = ce->getSubExpr();
2631         assert(e->getType()->hasPointerRepresentation());
2632         continue;
2633 
2634       // For consumptions, just emit the subexpression and thus elide
2635       // the retain/release pair.
2636       case CK_ARCConsumeObject: {
2637         llvm::Value *result = CGF.EmitScalarExpr(ce->getSubExpr());
2638         if (resultType) result = CGF.Builder.CreateBitCast(result, resultType);
2639         return TryEmitResult(result, true);
2640       }
2641 
2642       // Block extends are net +0.  Naively, we could just recurse on
2643       // the subexpression, but actually we need to ensure that the
2644       // value is copied as a block, so there's a little filter here.
2645       case CK_ARCExtendBlockObject: {
2646         llvm::Value *result; // will be a +0 value
2647 
2648         // If we can't safely assume the sub-expression will produce a
2649         // block-copied value, emit the sub-expression at +0.
2650         if (shouldEmitSeparateBlockRetain(ce->getSubExpr())) {
2651           result = CGF.EmitScalarExpr(ce->getSubExpr());
2652 
2653         // Otherwise, try to emit the sub-expression at +1 recursively.
2654         } else {
2655           TryEmitResult subresult
2656             = tryEmitARCRetainScalarExpr(CGF, ce->getSubExpr());
2657           result = subresult.getPointer();
2658 
2659           // If that produced a retained value, just use that,
2660           // possibly casting down.
2661           if (subresult.getInt()) {
2662             if (resultType)
2663               result = CGF.Builder.CreateBitCast(result, resultType);
2664             return TryEmitResult(result, true);
2665           }
2666 
2667           // Otherwise it's +0.
2668         }
2669 
2670         // Retain the object as a block, then cast down.
2671         result = CGF.EmitARCRetainBlock(result, /*mandatory*/ true);
2672         if (resultType) result = CGF.Builder.CreateBitCast(result, resultType);
2673         return TryEmitResult(result, true);
2674       }
2675 
2676       // For reclaims, emit the subexpression as a retained call and
2677       // skip the consumption.
2678       case CK_ARCReclaimReturnedObject: {
2679         llvm::Value *result = emitARCRetainCall(CGF, ce->getSubExpr());
2680         if (resultType) result = CGF.Builder.CreateBitCast(result, resultType);
2681         return TryEmitResult(result, true);
2682       }
2683 
2684       default:
2685         break;
2686       }
2687 
2688     // Skip __extension__.
2689     } else if (const UnaryOperator *op = dyn_cast<UnaryOperator>(e)) {
2690       if (op->getOpcode() == UO_Extension) {
2691         e = op->getSubExpr();
2692         continue;
2693       }
2694 
2695     // For calls and message sends, use the retained-call logic.
2696     // Delegate inits are a special case in that they're the only
2697     // returns-retained expression that *isn't* surrounded by
2698     // a consume.
2699     } else if (isa<CallExpr>(e) ||
2700                (isa<ObjCMessageExpr>(e) &&
2701                 !cast<ObjCMessageExpr>(e)->isDelegateInitCall())) {
2702       llvm::Value *result = emitARCRetainCall(CGF, e);
2703       if (resultType) result = CGF.Builder.CreateBitCast(result, resultType);
2704       return TryEmitResult(result, true);
2705 
2706     // Look through pseudo-object expressions.
2707     } else if (const PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) {
2708       TryEmitResult result
2709         = tryEmitARCRetainPseudoObject(CGF, pseudo);
2710       if (resultType) {
2711         llvm::Value *value = result.getPointer();
2712         value = CGF.Builder.CreateBitCast(value, resultType);
2713         result.setPointer(value);
2714       }
2715       return result;
2716     }
2717 
2718     // Conservatively halt the search at any other expression kind.
2719     break;
2720   }
2721 
2722   // We didn't find an obvious production, so emit what we've got and
2723   // tell the caller that we didn't manage to retain.
2724   llvm::Value *result = CGF.EmitScalarExpr(e);
2725   if (resultType) result = CGF.Builder.CreateBitCast(result, resultType);
2726   return TryEmitResult(result, false);
2727 }
2728 
emitARCRetainLoadOfScalar(CodeGenFunction & CGF,LValue lvalue,QualType type)2729 static llvm::Value *emitARCRetainLoadOfScalar(CodeGenFunction &CGF,
2730                                                 LValue lvalue,
2731                                                 QualType type) {
2732   TryEmitResult result = tryEmitARCRetainLoadOfScalar(CGF, lvalue, type);
2733   llvm::Value *value = result.getPointer();
2734   if (!result.getInt())
2735     value = CGF.EmitARCRetain(type, value);
2736   return value;
2737 }
2738 
2739 /// EmitARCRetainScalarExpr - Semantically equivalent to
2740 /// EmitARCRetainObject(e->getType(), EmitScalarExpr(e)), but making a
2741 /// best-effort attempt to peephole expressions that naturally produce
2742 /// retained objects.
EmitARCRetainScalarExpr(const Expr * e)2743 llvm::Value *CodeGenFunction::EmitARCRetainScalarExpr(const Expr *e) {
2744   // The retain needs to happen within the full-expression.
2745   if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
2746     enterFullExpression(cleanups);
2747     RunCleanupsScope scope(*this);
2748     return EmitARCRetainScalarExpr(cleanups->getSubExpr());
2749   }
2750 
2751   TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e);
2752   llvm::Value *value = result.getPointer();
2753   if (!result.getInt())
2754     value = EmitARCRetain(e->getType(), value);
2755   return value;
2756 }
2757 
2758 llvm::Value *
EmitARCRetainAutoreleaseScalarExpr(const Expr * e)2759 CodeGenFunction::EmitARCRetainAutoreleaseScalarExpr(const Expr *e) {
2760   // The retain needs to happen within the full-expression.
2761   if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
2762     enterFullExpression(cleanups);
2763     RunCleanupsScope scope(*this);
2764     return EmitARCRetainAutoreleaseScalarExpr(cleanups->getSubExpr());
2765   }
2766 
2767   TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e);
2768   llvm::Value *value = result.getPointer();
2769   if (result.getInt())
2770     value = EmitARCAutorelease(value);
2771   else
2772     value = EmitARCRetainAutorelease(e->getType(), value);
2773   return value;
2774 }
2775 
EmitARCExtendBlockObject(const Expr * e)2776 llvm::Value *CodeGenFunction::EmitARCExtendBlockObject(const Expr *e) {
2777   llvm::Value *result;
2778   bool doRetain;
2779 
2780   if (shouldEmitSeparateBlockRetain(e)) {
2781     result = EmitScalarExpr(e);
2782     doRetain = true;
2783   } else {
2784     TryEmitResult subresult = tryEmitARCRetainScalarExpr(*this, e);
2785     result = subresult.getPointer();
2786     doRetain = !subresult.getInt();
2787   }
2788 
2789   if (doRetain)
2790     result = EmitARCRetainBlock(result, /*mandatory*/ true);
2791   return EmitObjCConsumeObject(e->getType(), result);
2792 }
2793 
EmitObjCThrowOperand(const Expr * expr)2794 llvm::Value *CodeGenFunction::EmitObjCThrowOperand(const Expr *expr) {
2795   // In ARC, retain and autorelease the expression.
2796   if (getLangOpts().ObjCAutoRefCount) {
2797     // Do so before running any cleanups for the full-expression.
2798     // EmitARCRetainAutoreleaseScalarExpr does this for us.
2799     return EmitARCRetainAutoreleaseScalarExpr(expr);
2800   }
2801 
2802   // Otherwise, use the normal scalar-expression emission.  The
2803   // exception machinery doesn't do anything special with the
2804   // exception like retaining it, so there's no safety associated with
2805   // only running cleanups after the throw has started, and when it
2806   // matters it tends to be substantially inferior code.
2807   return EmitScalarExpr(expr);
2808 }
2809 
2810 std::pair<LValue,llvm::Value*>
EmitARCStoreStrong(const BinaryOperator * e,bool ignored)2811 CodeGenFunction::EmitARCStoreStrong(const BinaryOperator *e,
2812                                     bool ignored) {
2813   // Evaluate the RHS first.
2814   TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e->getRHS());
2815   llvm::Value *value = result.getPointer();
2816 
2817   bool hasImmediateRetain = result.getInt();
2818 
2819   // If we didn't emit a retained object, and the l-value is of block
2820   // type, then we need to emit the block-retain immediately in case
2821   // it invalidates the l-value.
2822   if (!hasImmediateRetain && e->getType()->isBlockPointerType()) {
2823     value = EmitARCRetainBlock(value, /*mandatory*/ false);
2824     hasImmediateRetain = true;
2825   }
2826 
2827   LValue lvalue = EmitLValue(e->getLHS());
2828 
2829   // If the RHS was emitted retained, expand this.
2830   if (hasImmediateRetain) {
2831     llvm::Value *oldValue = EmitLoadOfScalar(lvalue, SourceLocation());
2832     EmitStoreOfScalar(value, lvalue);
2833     EmitARCRelease(oldValue, lvalue.isARCPreciseLifetime());
2834   } else {
2835     value = EmitARCStoreStrong(lvalue, value, ignored);
2836   }
2837 
2838   return std::pair<LValue,llvm::Value*>(lvalue, value);
2839 }
2840 
2841 std::pair<LValue,llvm::Value*>
EmitARCStoreAutoreleasing(const BinaryOperator * e)2842 CodeGenFunction::EmitARCStoreAutoreleasing(const BinaryOperator *e) {
2843   llvm::Value *value = EmitARCRetainAutoreleaseScalarExpr(e->getRHS());
2844   LValue lvalue = EmitLValue(e->getLHS());
2845 
2846   EmitStoreOfScalar(value, lvalue);
2847 
2848   return std::pair<LValue,llvm::Value*>(lvalue, value);
2849 }
2850 
EmitObjCAutoreleasePoolStmt(const ObjCAutoreleasePoolStmt & ARPS)2851 void CodeGenFunction::EmitObjCAutoreleasePoolStmt(
2852                                           const ObjCAutoreleasePoolStmt &ARPS) {
2853   const Stmt *subStmt = ARPS.getSubStmt();
2854   const CompoundStmt &S = cast<CompoundStmt>(*subStmt);
2855 
2856   CGDebugInfo *DI = getDebugInfo();
2857   if (DI)
2858     DI->EmitLexicalBlockStart(Builder, S.getLBracLoc());
2859 
2860   // Keep track of the current cleanup stack depth.
2861   RunCleanupsScope Scope(*this);
2862   if (CGM.getLangOpts().ObjCRuntime.hasNativeARC()) {
2863     llvm::Value *token = EmitObjCAutoreleasePoolPush();
2864     EHStack.pushCleanup<CallObjCAutoreleasePoolObject>(NormalCleanup, token);
2865   } else {
2866     llvm::Value *token = EmitObjCMRRAutoreleasePoolPush();
2867     EHStack.pushCleanup<CallObjCMRRAutoreleasePoolObject>(NormalCleanup, token);
2868   }
2869 
2870   for (const auto *I : S.body())
2871     EmitStmt(I);
2872 
2873   if (DI)
2874     DI->EmitLexicalBlockEnd(Builder, S.getRBracLoc());
2875 }
2876 
2877 /// EmitExtendGCLifetime - Given a pointer to an Objective-C object,
2878 /// make sure it survives garbage collection until this point.
EmitExtendGCLifetime(llvm::Value * object)2879 void CodeGenFunction::EmitExtendGCLifetime(llvm::Value *object) {
2880   // We just use an inline assembly.
2881   llvm::FunctionType *extenderType
2882     = llvm::FunctionType::get(VoidTy, VoidPtrTy, RequiredArgs::All);
2883   llvm::Value *extender
2884     = llvm::InlineAsm::get(extenderType,
2885                            /* assembly */ "",
2886                            /* constraints */ "r",
2887                            /* side effects */ true);
2888 
2889   object = Builder.CreateBitCast(object, VoidPtrTy);
2890   EmitNounwindRuntimeCall(extender, object);
2891 }
2892 
2893 /// GenerateObjCAtomicSetterCopyHelperFunction - Given a c++ object type with
2894 /// non-trivial copy assignment function, produce following helper function.
2895 /// static void copyHelper(Ty *dest, const Ty *source) { *dest = *source; }
2896 ///
2897 llvm::Constant *
GenerateObjCAtomicSetterCopyHelperFunction(const ObjCPropertyImplDecl * PID)2898 CodeGenFunction::GenerateObjCAtomicSetterCopyHelperFunction(
2899                                         const ObjCPropertyImplDecl *PID) {
2900   if (!getLangOpts().CPlusPlus ||
2901       !getLangOpts().ObjCRuntime.hasAtomicCopyHelper())
2902     return nullptr;
2903   QualType Ty = PID->getPropertyIvarDecl()->getType();
2904   if (!Ty->isRecordType())
2905     return nullptr;
2906   const ObjCPropertyDecl *PD = PID->getPropertyDecl();
2907   if ((!(PD->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_atomic)))
2908     return nullptr;
2909   llvm::Constant *HelperFn = nullptr;
2910   if (hasTrivialSetExpr(PID))
2911     return nullptr;
2912   assert(PID->getSetterCXXAssignment() && "SetterCXXAssignment - null");
2913   if ((HelperFn = CGM.getAtomicSetterHelperFnMap(Ty)))
2914     return HelperFn;
2915 
2916   ASTContext &C = getContext();
2917   IdentifierInfo *II
2918     = &CGM.getContext().Idents.get("__assign_helper_atomic_property_");
2919   FunctionDecl *FD = FunctionDecl::Create(C,
2920                                           C.getTranslationUnitDecl(),
2921                                           SourceLocation(),
2922                                           SourceLocation(), II, C.VoidTy,
2923                                           nullptr, SC_Static,
2924                                           false,
2925                                           false);
2926 
2927   QualType DestTy = C.getPointerType(Ty);
2928   QualType SrcTy = Ty;
2929   SrcTy.addConst();
2930   SrcTy = C.getPointerType(SrcTy);
2931 
2932   FunctionArgList args;
2933   ImplicitParamDecl dstDecl(getContext(), FD, SourceLocation(), nullptr,DestTy);
2934   args.push_back(&dstDecl);
2935   ImplicitParamDecl srcDecl(getContext(), FD, SourceLocation(), nullptr, SrcTy);
2936   args.push_back(&srcDecl);
2937 
2938   const CGFunctionInfo &FI = CGM.getTypes().arrangeFreeFunctionDeclaration(
2939       C.VoidTy, args, FunctionType::ExtInfo(), RequiredArgs::All);
2940 
2941   llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
2942 
2943   llvm::Function *Fn =
2944     llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
2945                            "__assign_helper_atomic_property_",
2946                            &CGM.getModule());
2947 
2948   CGM.SetInternalFunctionAttributes(nullptr, Fn, FI);
2949 
2950   StartFunction(FD, C.VoidTy, Fn, FI, args);
2951 
2952   DeclRefExpr DstExpr(&dstDecl, false, DestTy,
2953                       VK_RValue, SourceLocation());
2954   UnaryOperator DST(&DstExpr, UO_Deref, DestTy->getPointeeType(),
2955                     VK_LValue, OK_Ordinary, SourceLocation());
2956 
2957   DeclRefExpr SrcExpr(&srcDecl, false, SrcTy,
2958                       VK_RValue, SourceLocation());
2959   UnaryOperator SRC(&SrcExpr, UO_Deref, SrcTy->getPointeeType(),
2960                     VK_LValue, OK_Ordinary, SourceLocation());
2961 
2962   Expr *Args[2] = { &DST, &SRC };
2963   CallExpr *CalleeExp = cast<CallExpr>(PID->getSetterCXXAssignment());
2964   CXXOperatorCallExpr TheCall(C, OO_Equal, CalleeExp->getCallee(),
2965                               Args, DestTy->getPointeeType(),
2966                               VK_LValue, SourceLocation(), false);
2967 
2968   EmitStmt(&TheCall);
2969 
2970   FinishFunction();
2971   HelperFn = llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
2972   CGM.setAtomicSetterHelperFnMap(Ty, HelperFn);
2973   return HelperFn;
2974 }
2975 
2976 llvm::Constant *
GenerateObjCAtomicGetterCopyHelperFunction(const ObjCPropertyImplDecl * PID)2977 CodeGenFunction::GenerateObjCAtomicGetterCopyHelperFunction(
2978                                             const ObjCPropertyImplDecl *PID) {
2979   if (!getLangOpts().CPlusPlus ||
2980       !getLangOpts().ObjCRuntime.hasAtomicCopyHelper())
2981     return nullptr;
2982   const ObjCPropertyDecl *PD = PID->getPropertyDecl();
2983   QualType Ty = PD->getType();
2984   if (!Ty->isRecordType())
2985     return nullptr;
2986   if ((!(PD->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_atomic)))
2987     return nullptr;
2988   llvm::Constant *HelperFn = nullptr;
2989 
2990   if (hasTrivialGetExpr(PID))
2991     return nullptr;
2992   assert(PID->getGetterCXXConstructor() && "getGetterCXXConstructor - null");
2993   if ((HelperFn = CGM.getAtomicGetterHelperFnMap(Ty)))
2994     return HelperFn;
2995 
2996 
2997   ASTContext &C = getContext();
2998   IdentifierInfo *II
2999   = &CGM.getContext().Idents.get("__copy_helper_atomic_property_");
3000   FunctionDecl *FD = FunctionDecl::Create(C,
3001                                           C.getTranslationUnitDecl(),
3002                                           SourceLocation(),
3003                                           SourceLocation(), II, C.VoidTy,
3004                                           nullptr, SC_Static,
3005                                           false,
3006                                           false);
3007 
3008   QualType DestTy = C.getPointerType(Ty);
3009   QualType SrcTy = Ty;
3010   SrcTy.addConst();
3011   SrcTy = C.getPointerType(SrcTy);
3012 
3013   FunctionArgList args;
3014   ImplicitParamDecl dstDecl(getContext(), FD, SourceLocation(), nullptr,DestTy);
3015   args.push_back(&dstDecl);
3016   ImplicitParamDecl srcDecl(getContext(), FD, SourceLocation(), nullptr, SrcTy);
3017   args.push_back(&srcDecl);
3018 
3019   const CGFunctionInfo &FI = CGM.getTypes().arrangeFreeFunctionDeclaration(
3020       C.VoidTy, args, FunctionType::ExtInfo(), RequiredArgs::All);
3021 
3022   llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
3023 
3024   llvm::Function *Fn =
3025   llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
3026                          "__copy_helper_atomic_property_", &CGM.getModule());
3027 
3028   CGM.SetInternalFunctionAttributes(nullptr, Fn, FI);
3029 
3030   StartFunction(FD, C.VoidTy, Fn, FI, args);
3031 
3032   DeclRefExpr SrcExpr(&srcDecl, false, SrcTy,
3033                       VK_RValue, SourceLocation());
3034 
3035   UnaryOperator SRC(&SrcExpr, UO_Deref, SrcTy->getPointeeType(),
3036                     VK_LValue, OK_Ordinary, SourceLocation());
3037 
3038   CXXConstructExpr *CXXConstExpr =
3039     cast<CXXConstructExpr>(PID->getGetterCXXConstructor());
3040 
3041   SmallVector<Expr*, 4> ConstructorArgs;
3042   ConstructorArgs.push_back(&SRC);
3043   ConstructorArgs.append(std::next(CXXConstExpr->arg_begin()),
3044                          CXXConstExpr->arg_end());
3045 
3046   CXXConstructExpr *TheCXXConstructExpr =
3047     CXXConstructExpr::Create(C, Ty, SourceLocation(),
3048                              CXXConstExpr->getConstructor(),
3049                              CXXConstExpr->isElidable(),
3050                              ConstructorArgs,
3051                              CXXConstExpr->hadMultipleCandidates(),
3052                              CXXConstExpr->isListInitialization(),
3053                              CXXConstExpr->isStdInitListInitialization(),
3054                              CXXConstExpr->requiresZeroInitialization(),
3055                              CXXConstExpr->getConstructionKind(),
3056                              SourceRange());
3057 
3058   DeclRefExpr DstExpr(&dstDecl, false, DestTy,
3059                       VK_RValue, SourceLocation());
3060 
3061   RValue DV = EmitAnyExpr(&DstExpr);
3062   CharUnits Alignment
3063     = getContext().getTypeAlignInChars(TheCXXConstructExpr->getType());
3064   EmitAggExpr(TheCXXConstructExpr,
3065               AggValueSlot::forAddr(Address(DV.getScalarVal(), Alignment),
3066                                     Qualifiers(),
3067                                     AggValueSlot::IsDestructed,
3068                                     AggValueSlot::DoesNotNeedGCBarriers,
3069                                     AggValueSlot::IsNotAliased));
3070 
3071   FinishFunction();
3072   HelperFn = llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
3073   CGM.setAtomicGetterHelperFnMap(Ty, HelperFn);
3074   return HelperFn;
3075 }
3076 
3077 llvm::Value *
EmitBlockCopyAndAutorelease(llvm::Value * Block,QualType Ty)3078 CodeGenFunction::EmitBlockCopyAndAutorelease(llvm::Value *Block, QualType Ty) {
3079   // Get selectors for retain/autorelease.
3080   IdentifierInfo *CopyID = &getContext().Idents.get("copy");
3081   Selector CopySelector =
3082       getContext().Selectors.getNullarySelector(CopyID);
3083   IdentifierInfo *AutoreleaseID = &getContext().Idents.get("autorelease");
3084   Selector AutoreleaseSelector =
3085       getContext().Selectors.getNullarySelector(AutoreleaseID);
3086 
3087   // Emit calls to retain/autorelease.
3088   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
3089   llvm::Value *Val = Block;
3090   RValue Result;
3091   Result = Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
3092                                        Ty, CopySelector,
3093                                        Val, CallArgList(), nullptr, nullptr);
3094   Val = Result.getScalarVal();
3095   Result = Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
3096                                        Ty, AutoreleaseSelector,
3097                                        Val, CallArgList(), nullptr, nullptr);
3098   Val = Result.getScalarVal();
3099   return Val;
3100 }
3101 
3102 
~CGObjCRuntime()3103 CGObjCRuntime::~CGObjCRuntime() {}
3104