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 AdjustRelatedResultType(CodeGenFunction &CGF,
35                                       QualType ET,
36                                       const ObjCMethodDecl *Method,
37                                       RValue Result);
38 
39 /// Given the address of a variable of pointer type, find the correct
40 /// null to store into it.
getNullForVariable(llvm::Value * addr)41 static llvm::Constant *getNullForVariable(llvm::Value *addr) {
42   llvm::Type *type =
43     cast<llvm::PointerType>(addr->getType())->getElementType();
44   return llvm::ConstantPointerNull::get(cast<llvm::PointerType>(type));
45 }
46 
47 /// Emits an instance of NSConstantString representing the object.
EmitObjCStringLiteral(const ObjCStringLiteral * E)48 llvm::Value *CodeGenFunction::EmitObjCStringLiteral(const ObjCStringLiteral *E)
49 {
50   llvm::Constant *C =
51       CGM.getObjCRuntime().GenerateConstantString(E->getString());
52   // FIXME: This bitcast should just be made an invariant on the Runtime.
53   return llvm::ConstantExpr::getBitCast(C, ConvertType(E->getType()));
54 }
55 
56 /// EmitObjCBoxedExpr - This routine generates code to call
57 /// the appropriate expression boxing method. This will either be
58 /// one of +[NSNumber numberWith<Type>:], or +[NSString stringWithUTF8String:].
59 ///
60 llvm::Value *
EmitObjCBoxedExpr(const ObjCBoxedExpr * E)61 CodeGenFunction::EmitObjCBoxedExpr(const ObjCBoxedExpr *E) {
62   // Generate the correct selector for this literal's concrete type.
63   // Get the method.
64   const ObjCMethodDecl *BoxingMethod = E->getBoxingMethod();
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   EmitCallArgs(Args, BoxingMethod, E->arg_begin(), E->arg_end());
78 
79   RValue result = Runtime.GenerateMessageSend(
80       *this, ReturnValueSlot(), BoxingMethod->getReturnType(), Sel, Receiver,
81       Args, ClassDecl, BoxingMethod);
82   return Builder.CreateBitCast(result.getScalarVal(),
83                                ConvertType(E->getType()));
84 }
85 
EmitObjCCollectionLiteral(const Expr * E,const ObjCMethodDecl * MethodWithObjects)86 llvm::Value *CodeGenFunction::EmitObjCCollectionLiteral(const Expr *E,
87                                     const ObjCMethodDecl *MethodWithObjects) {
88   ASTContext &Context = CGM.getContext();
89   const ObjCDictionaryLiteral *DLE = nullptr;
90   const ObjCArrayLiteral *ALE = dyn_cast<ObjCArrayLiteral>(E);
91   if (!ALE)
92     DLE = cast<ObjCDictionaryLiteral>(E);
93 
94   // Compute the type of the array we're initializing.
95   uint64_t NumElements =
96     ALE ? ALE->getNumElements() : DLE->getNumElements();
97   llvm::APInt APNumElements(Context.getTypeSize(Context.getSizeType()),
98                             NumElements);
99   QualType ElementType = Context.getObjCIdType().withConst();
100   QualType ElementArrayType
101     = Context.getConstantArrayType(ElementType, APNumElements,
102                                    ArrayType::Normal, /*IndexTypeQuals=*/0);
103 
104   // Allocate the temporary array(s).
105   llvm::AllocaInst *Objects = CreateMemTemp(ElementArrayType, "objects");
106   llvm::AllocaInst *Keys = nullptr;
107   if (DLE)
108     Keys = CreateMemTemp(ElementArrayType, "keys");
109 
110   // In ARC, we may need to do extra work to keep all the keys and
111   // values alive until after the call.
112   SmallVector<llvm::Value *, 16> NeededObjects;
113   bool TrackNeededObjects =
114     (getLangOpts().ObjCAutoRefCount &&
115     CGM.getCodeGenOpts().OptimizationLevel != 0);
116 
117   // Perform the actual initialialization of the array(s).
118   for (uint64_t i = 0; i < NumElements; i++) {
119     if (ALE) {
120       // Emit the element and store it to the appropriate array slot.
121       const Expr *Rhs = ALE->getElement(i);
122       LValue LV = LValue::MakeAddr(
123           Builder.CreateStructGEP(Objects->getAllocatedType(), Objects, i),
124           ElementType, Context.getTypeAlignInChars(Rhs->getType()), Context);
125 
126       llvm::Value *value = EmitScalarExpr(Rhs);
127       EmitStoreThroughLValue(RValue::get(value), LV, true);
128       if (TrackNeededObjects) {
129         NeededObjects.push_back(value);
130       }
131     } else {
132       // Emit the key and store it to the appropriate array slot.
133       const Expr *Key = DLE->getKeyValueElement(i).Key;
134       LValue KeyLV = LValue::MakeAddr(
135           Builder.CreateStructGEP(Keys->getAllocatedType(), Keys, i),
136           ElementType, Context.getTypeAlignInChars(Key->getType()), Context);
137       llvm::Value *keyValue = EmitScalarExpr(Key);
138       EmitStoreThroughLValue(RValue::get(keyValue), KeyLV, /*isInit=*/true);
139 
140       // Emit the value and store it to the appropriate array slot.
141       const Expr *Value = DLE->getKeyValueElement(i).Value;
142       LValue ValueLV = LValue::MakeAddr(
143           Builder.CreateStructGEP(Objects->getAllocatedType(), Objects, i),
144           ElementType, Context.getTypeAlignInChars(Value->getType()), Context);
145       llvm::Value *valueValue = EmitScalarExpr(Value);
146       EmitStoreThroughLValue(RValue::get(valueValue), ValueLV, /*isInit=*/true);
147       if (TrackNeededObjects) {
148         NeededObjects.push_back(keyValue);
149         NeededObjects.push_back(valueValue);
150       }
151     }
152   }
153 
154   // Generate the argument list.
155   CallArgList Args;
156   ObjCMethodDecl::param_const_iterator PI = MethodWithObjects->param_begin();
157   const ParmVarDecl *argDecl = *PI++;
158   QualType ArgQT = argDecl->getType().getUnqualifiedType();
159   Args.add(RValue::get(Objects), ArgQT);
160   if (DLE) {
161     argDecl = *PI++;
162     ArgQT = argDecl->getType().getUnqualifiedType();
163     Args.add(RValue::get(Keys), ArgQT);
164   }
165   argDecl = *PI;
166   ArgQT = argDecl->getType().getUnqualifiedType();
167   llvm::Value *Count =
168     llvm::ConstantInt::get(CGM.getTypes().ConvertType(ArgQT), NumElements);
169   Args.add(RValue::get(Count), ArgQT);
170 
171   // Generate a reference to the class pointer, which will be the receiver.
172   Selector Sel = MethodWithObjects->getSelector();
173   QualType ResultType = E->getType();
174   const ObjCObjectPointerType *InterfacePointerType
175     = ResultType->getAsObjCInterfacePointerType();
176   ObjCInterfaceDecl *Class
177     = InterfacePointerType->getObjectType()->getInterface();
178   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
179   llvm::Value *Receiver = Runtime.GetClass(*this, Class);
180 
181   // Generate the message send.
182   RValue result = Runtime.GenerateMessageSend(
183       *this, ReturnValueSlot(), MethodWithObjects->getReturnType(), Sel,
184       Receiver, Args, Class, MethodWithObjects);
185 
186   // The above message send needs these objects, but in ARC they are
187   // passed in a buffer that is essentially __unsafe_unretained.
188   // Therefore we must prevent the optimizer from releasing them until
189   // after the call.
190   if (TrackNeededObjects) {
191     EmitARCIntrinsicUse(NeededObjects);
192   }
193 
194   return Builder.CreateBitCast(result.getScalarVal(),
195                                ConvertType(E->getType()));
196 }
197 
EmitObjCArrayLiteral(const ObjCArrayLiteral * E)198 llvm::Value *CodeGenFunction::EmitObjCArrayLiteral(const ObjCArrayLiteral *E) {
199   return EmitObjCCollectionLiteral(E, E->getArrayWithObjectsMethod());
200 }
201 
EmitObjCDictionaryLiteral(const ObjCDictionaryLiteral * E)202 llvm::Value *CodeGenFunction::EmitObjCDictionaryLiteral(
203                                             const ObjCDictionaryLiteral *E) {
204   return EmitObjCCollectionLiteral(E, E->getDictWithObjectsMethod());
205 }
206 
207 /// Emit a selector.
EmitObjCSelectorExpr(const ObjCSelectorExpr * E)208 llvm::Value *CodeGenFunction::EmitObjCSelectorExpr(const ObjCSelectorExpr *E) {
209   // Untyped selector.
210   // Note that this implementation allows for non-constant strings to be passed
211   // as arguments to @selector().  Currently, the only thing preventing this
212   // behaviour is the type checking in the front end.
213   return CGM.getObjCRuntime().GetSelector(*this, E->getSelector());
214 }
215 
EmitObjCProtocolExpr(const ObjCProtocolExpr * E)216 llvm::Value *CodeGenFunction::EmitObjCProtocolExpr(const ObjCProtocolExpr *E) {
217   // FIXME: This should pass the Decl not the name.
218   return CGM.getObjCRuntime().GenerateProtocolRef(*this, E->getProtocol());
219 }
220 
221 /// \brief Adjust the type of the result of an Objective-C message send
222 /// expression when the method has a related result type.
AdjustRelatedResultType(CodeGenFunction & CGF,QualType ExpT,const ObjCMethodDecl * Method,RValue Result)223 static RValue AdjustRelatedResultType(CodeGenFunction &CGF,
224                                       QualType ExpT,
225                                       const ObjCMethodDecl *Method,
226                                       RValue Result) {
227   if (!Method)
228     return Result;
229 
230   if (!Method->hasRelatedResultType() ||
231       CGF.getContext().hasSameType(ExpT, Method->getReturnType()) ||
232       !Result.isScalar())
233     return Result;
234 
235   // We have applied a related result type. Cast the rvalue appropriately.
236   return RValue::get(CGF.Builder.CreateBitCast(Result.getScalarVal(),
237                                                CGF.ConvertType(ExpT)));
238 }
239 
240 /// Decide whether to extend the lifetime of the receiver of a
241 /// returns-inner-pointer message.
242 static bool
shouldExtendReceiverForInnerPointerMessage(const ObjCMessageExpr * message)243 shouldExtendReceiverForInnerPointerMessage(const ObjCMessageExpr *message) {
244   switch (message->getReceiverKind()) {
245 
246   // For a normal instance message, we should extend unless the
247   // receiver is loaded from a variable with precise lifetime.
248   case ObjCMessageExpr::Instance: {
249     const Expr *receiver = message->getInstanceReceiver();
250     const ImplicitCastExpr *ice = dyn_cast<ImplicitCastExpr>(receiver);
251     if (!ice || ice->getCastKind() != CK_LValueToRValue) return true;
252     receiver = ice->getSubExpr()->IgnoreParens();
253 
254     // Only __strong variables.
255     if (receiver->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
256       return true;
257 
258     // All ivars and fields have precise lifetime.
259     if (isa<MemberExpr>(receiver) || isa<ObjCIvarRefExpr>(receiver))
260       return false;
261 
262     // Otherwise, check for variables.
263     const DeclRefExpr *declRef = dyn_cast<DeclRefExpr>(ice->getSubExpr());
264     if (!declRef) return true;
265     const VarDecl *var = dyn_cast<VarDecl>(declRef->getDecl());
266     if (!var) return true;
267 
268     // All variables have precise lifetime except local variables with
269     // automatic storage duration that aren't specially marked.
270     return (var->hasLocalStorage() &&
271             !var->hasAttr<ObjCPreciseLifetimeAttr>());
272   }
273 
274   case ObjCMessageExpr::Class:
275   case ObjCMessageExpr::SuperClass:
276     // It's never necessary for class objects.
277     return false;
278 
279   case ObjCMessageExpr::SuperInstance:
280     // We generally assume that 'self' lives throughout a method call.
281     return false;
282   }
283 
284   llvm_unreachable("invalid receiver kind");
285 }
286 
EmitObjCMessageExpr(const ObjCMessageExpr * E,ReturnValueSlot Return)287 RValue CodeGenFunction::EmitObjCMessageExpr(const ObjCMessageExpr *E,
288                                             ReturnValueSlot Return) {
289   // Only the lookup mechanism and first two arguments of the method
290   // implementation vary between runtimes.  We can get the receiver and
291   // arguments in generic code.
292 
293   bool isDelegateInit = E->isDelegateInitCall();
294 
295   const ObjCMethodDecl *method = E->getMethodDecl();
296 
297   // We don't retain the receiver in delegate init calls, and this is
298   // safe because the receiver value is always loaded from 'self',
299   // which we zero out.  We don't want to Block_copy block receivers,
300   // though.
301   bool retainSelf =
302     (!isDelegateInit &&
303      CGM.getLangOpts().ObjCAutoRefCount &&
304      method &&
305      method->hasAttr<NSConsumesSelfAttr>());
306 
307   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
308   bool isSuperMessage = false;
309   bool isClassMessage = false;
310   ObjCInterfaceDecl *OID = nullptr;
311   // Find the receiver
312   QualType ReceiverType;
313   llvm::Value *Receiver = nullptr;
314   switch (E->getReceiverKind()) {
315   case ObjCMessageExpr::Instance:
316     ReceiverType = E->getInstanceReceiver()->getType();
317     if (retainSelf) {
318       TryEmitResult ter = tryEmitARCRetainScalarExpr(*this,
319                                                    E->getInstanceReceiver());
320       Receiver = ter.getPointer();
321       if (ter.getInt()) retainSelf = false;
322     } else
323       Receiver = EmitScalarExpr(E->getInstanceReceiver());
324     break;
325 
326   case ObjCMessageExpr::Class: {
327     ReceiverType = E->getClassReceiver();
328     const ObjCObjectType *ObjTy = ReceiverType->getAs<ObjCObjectType>();
329     assert(ObjTy && "Invalid Objective-C class message send");
330     OID = ObjTy->getInterface();
331     assert(OID && "Invalid Objective-C class message send");
332     Receiver = Runtime.GetClass(*this, OID);
333     isClassMessage = true;
334     break;
335   }
336 
337   case ObjCMessageExpr::SuperInstance:
338     ReceiverType = E->getSuperType();
339     Receiver = LoadObjCSelf();
340     isSuperMessage = true;
341     break;
342 
343   case ObjCMessageExpr::SuperClass:
344     ReceiverType = E->getSuperType();
345     Receiver = LoadObjCSelf();
346     isSuperMessage = true;
347     isClassMessage = true;
348     break;
349   }
350 
351   if (retainSelf)
352     Receiver = EmitARCRetainNonBlock(Receiver);
353 
354   // In ARC, we sometimes want to "extend the lifetime"
355   // (i.e. retain+autorelease) of receivers of returns-inner-pointer
356   // messages.
357   if (getLangOpts().ObjCAutoRefCount && method &&
358       method->hasAttr<ObjCReturnsInnerPointerAttr>() &&
359       shouldExtendReceiverForInnerPointerMessage(E))
360     Receiver = EmitARCRetainAutorelease(ReceiverType, Receiver);
361 
362   QualType ResultType = method ? method->getReturnType() : E->getType();
363 
364   CallArgList Args;
365   EmitCallArgs(Args, method, E->arg_begin(), E->arg_end());
366 
367   // For delegate init calls in ARC, do an unsafe store of null into
368   // self.  This represents the call taking direct ownership of that
369   // value.  We have to do this after emitting the other call
370   // arguments because they might also reference self, but we don't
371   // have to worry about any of them modifying self because that would
372   // be an undefined read and write of an object in unordered
373   // expressions.
374   if (isDelegateInit) {
375     assert(getLangOpts().ObjCAutoRefCount &&
376            "delegate init calls should only be marked in ARC");
377 
378     // Do an unsafe store of null into self.
379     llvm::Value *selfAddr =
380       LocalDeclMap[cast<ObjCMethodDecl>(CurCodeDecl)->getSelfDecl()];
381     assert(selfAddr && "no self entry for a delegate init call?");
382 
383     Builder.CreateStore(getNullForVariable(selfAddr), selfAddr);
384   }
385 
386   RValue result;
387   if (isSuperMessage) {
388     // super is only valid in an Objective-C method
389     const ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(CurFuncDecl);
390     bool isCategoryImpl = isa<ObjCCategoryImplDecl>(OMD->getDeclContext());
391     result = Runtime.GenerateMessageSendSuper(*this, Return, ResultType,
392                                               E->getSelector(),
393                                               OMD->getClassInterface(),
394                                               isCategoryImpl,
395                                               Receiver,
396                                               isClassMessage,
397                                               Args,
398                                               method);
399   } else {
400     result = Runtime.GenerateMessageSend(*this, Return, ResultType,
401                                          E->getSelector(),
402                                          Receiver, Args, OID,
403                                          method);
404   }
405 
406   // For delegate init calls in ARC, implicitly store the result of
407   // the call back into self.  This takes ownership of the value.
408   if (isDelegateInit) {
409     llvm::Value *selfAddr =
410       LocalDeclMap[cast<ObjCMethodDecl>(CurCodeDecl)->getSelfDecl()];
411     llvm::Value *newSelf = result.getScalarVal();
412 
413     // The delegate return type isn't necessarily a matching type; in
414     // fact, it's quite likely to be 'id'.
415     llvm::Type *selfTy =
416       cast<llvm::PointerType>(selfAddr->getType())->getElementType();
417     newSelf = Builder.CreateBitCast(newSelf, selfTy);
418 
419     Builder.CreateStore(newSelf, selfAddr);
420   }
421 
422   return AdjustRelatedResultType(*this, E->getType(), method, result);
423 }
424 
425 namespace {
426 struct FinishARCDealloc : EHScopeStack::Cleanup {
Emit__anon2e547c680111::FinishARCDealloc427   void Emit(CodeGenFunction &CGF, Flags flags) override {
428     const ObjCMethodDecl *method = cast<ObjCMethodDecl>(CGF.CurCodeDecl);
429 
430     const ObjCImplDecl *impl = cast<ObjCImplDecl>(method->getDeclContext());
431     const ObjCInterfaceDecl *iface = impl->getClassInterface();
432     if (!iface->getSuperClass()) return;
433 
434     bool isCategory = isa<ObjCCategoryImplDecl>(impl);
435 
436     // Call [super dealloc] if we have a superclass.
437     llvm::Value *self = CGF.LoadObjCSelf();
438 
439     CallArgList args;
440     CGF.CGM.getObjCRuntime().GenerateMessageSendSuper(CGF, ReturnValueSlot(),
441                                                       CGF.getContext().VoidTy,
442                                                       method->getSelector(),
443                                                       iface,
444                                                       isCategory,
445                                                       self,
446                                                       /*is class msg*/ false,
447                                                       args,
448                                                       method);
449   }
450 };
451 }
452 
453 /// StartObjCMethod - Begin emission of an ObjCMethod. This generates
454 /// the LLVM function and sets the other context used by
455 /// CodeGenFunction.
StartObjCMethod(const ObjCMethodDecl * OMD,const ObjCContainerDecl * CD)456 void CodeGenFunction::StartObjCMethod(const ObjCMethodDecl *OMD,
457                                       const ObjCContainerDecl *CD) {
458   SourceLocation StartLoc = OMD->getLocStart();
459   FunctionArgList args;
460   // Check if we should generate debug info for this method.
461   if (OMD->hasAttr<NoDebugAttr>())
462     DebugInfo = nullptr; // disable debug info indefinitely for this function
463 
464   llvm::Function *Fn = CGM.getObjCRuntime().GenerateMethod(OMD, CD);
465 
466   const CGFunctionInfo &FI = CGM.getTypes().arrangeObjCMethodDeclaration(OMD);
467   CGM.SetInternalFunctionAttributes(OMD, Fn, FI);
468 
469   args.push_back(OMD->getSelfDecl());
470   args.push_back(OMD->getCmdDecl());
471 
472   args.append(OMD->param_begin(), OMD->param_end());
473 
474   CurGD = OMD;
475   CurEHLocation = OMD->getLocEnd();
476 
477   StartFunction(OMD, OMD->getReturnType(), Fn, FI, args,
478                 OMD->getLocation(), StartLoc);
479 
480   // In ARC, certain methods get an extra cleanup.
481   if (CGM.getLangOpts().ObjCAutoRefCount &&
482       OMD->isInstanceMethod() &&
483       OMD->getSelector().isUnarySelector()) {
484     const IdentifierInfo *ident =
485       OMD->getSelector().getIdentifierInfoForSlot(0);
486     if (ident->isStr("dealloc"))
487       EHStack.pushCleanup<FinishARCDealloc>(getARCCleanupKind());
488   }
489 }
490 
491 static llvm::Value *emitARCRetainLoadOfScalar(CodeGenFunction &CGF,
492                                               LValue lvalue, QualType type);
493 
494 /// Generate an Objective-C method.  An Objective-C method is a C function with
495 /// its pointer, name, and types registered in the class struture.
GenerateObjCMethod(const ObjCMethodDecl * OMD)496 void CodeGenFunction::GenerateObjCMethod(const ObjCMethodDecl *OMD) {
497   StartObjCMethod(OMD, OMD->getClassInterface());
498   PGO.assignRegionCounters(OMD, CurFn);
499   assert(isa<CompoundStmt>(OMD->getBody()));
500   RegionCounter Cnt = getPGORegionCounter(OMD->getBody());
501   Cnt.beginRegion(Builder);
502   EmitCompoundStmtWithoutScope(*cast<CompoundStmt>(OMD->getBody()));
503   FinishFunction(OMD->getBodyRBrace());
504 }
505 
506 /// emitStructGetterCall - Call the runtime function to load a property
507 /// into the return value slot.
emitStructGetterCall(CodeGenFunction & CGF,ObjCIvarDecl * ivar,bool isAtomic,bool hasStrong)508 static void emitStructGetterCall(CodeGenFunction &CGF, ObjCIvarDecl *ivar,
509                                  bool isAtomic, bool hasStrong) {
510   ASTContext &Context = CGF.getContext();
511 
512   llvm::Value *src =
513     CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), CGF.LoadObjCSelf(),
514                           ivar, 0).getAddress();
515 
516   // objc_copyStruct (ReturnValue, &structIvar,
517   //                  sizeof (Type of Ivar), isAtomic, false);
518   CallArgList args;
519 
520   llvm::Value *dest = CGF.Builder.CreateBitCast(CGF.ReturnValue, CGF.VoidPtrTy);
521   args.add(RValue::get(dest), Context.VoidPtrTy);
522 
523   src = CGF.Builder.CreateBitCast(src, CGF.VoidPtrTy);
524   args.add(RValue::get(src), Context.VoidPtrTy);
525 
526   CharUnits size = CGF.getContext().getTypeSizeInChars(ivar->getType());
527   args.add(RValue::get(CGF.CGM.getSize(size)), Context.getSizeType());
528   args.add(RValue::get(CGF.Builder.getInt1(isAtomic)), Context.BoolTy);
529   args.add(RValue::get(CGF.Builder.getInt1(hasStrong)), Context.BoolTy);
530 
531   llvm::Value *fn = CGF.CGM.getObjCRuntime().GetGetStructFunction();
532   CGF.EmitCall(CGF.getTypes().arrangeFreeFunctionCall(Context.VoidTy, args,
533                                                       FunctionType::ExtInfo(),
534                                                       RequiredArgs::All),
535                fn, ReturnValueSlot(), args);
536 }
537 
538 /// Determine whether the given architecture supports unaligned atomic
539 /// accesses.  They don't have to be fast, just faster than a function
540 /// call and a mutex.
hasUnalignedAtomics(llvm::Triple::ArchType arch)541 static bool hasUnalignedAtomics(llvm::Triple::ArchType arch) {
542   // FIXME: Allow unaligned atomic load/store on x86.  (It is not
543   // currently supported by the backend.)
544   return 0;
545 }
546 
547 /// Return the maximum size that permits atomic accesses for the given
548 /// architecture.
getMaxAtomicAccessSize(CodeGenModule & CGM,llvm::Triple::ArchType arch)549 static CharUnits getMaxAtomicAccessSize(CodeGenModule &CGM,
550                                         llvm::Triple::ArchType arch) {
551   // ARM has 8-byte atomic accesses, but it's not clear whether we
552   // want to rely on them here.
553 
554   // In the default case, just assume that any size up to a pointer is
555   // fine given adequate alignment.
556   return CharUnits::fromQuantity(CGM.PointerSizeInBytes);
557 }
558 
559 namespace {
560   class PropertyImplStrategy {
561   public:
562     enum StrategyKind {
563       /// The 'native' strategy is to use the architecture's provided
564       /// reads and writes.
565       Native,
566 
567       /// Use objc_setProperty and objc_getProperty.
568       GetSetProperty,
569 
570       /// Use objc_setProperty for the setter, but use expression
571       /// evaluation for the getter.
572       SetPropertyAndExpressionGet,
573 
574       /// Use objc_copyStruct.
575       CopyStruct,
576 
577       /// The 'expression' strategy is to emit normal assignment or
578       /// lvalue-to-rvalue expressions.
579       Expression
580     };
581 
getKind() const582     StrategyKind getKind() const { return StrategyKind(Kind); }
583 
hasStrongMember() const584     bool hasStrongMember() const { return HasStrong; }
isAtomic() const585     bool isAtomic() const { return IsAtomic; }
isCopy() const586     bool isCopy() const { return IsCopy; }
587 
getIvarSize() const588     CharUnits getIvarSize() const { return IvarSize; }
getIvarAlignment() const589     CharUnits getIvarAlignment() const { return IvarAlignment; }
590 
591     PropertyImplStrategy(CodeGenModule &CGM,
592                          const ObjCPropertyImplDecl *propImpl);
593 
594   private:
595     unsigned Kind : 8;
596     unsigned IsAtomic : 1;
597     unsigned IsCopy : 1;
598     unsigned HasStrong : 1;
599 
600     CharUnits IvarSize;
601     CharUnits IvarAlignment;
602   };
603 }
604 
605 /// Pick an implementation strategy for the given property synthesis.
PropertyImplStrategy(CodeGenModule & CGM,const ObjCPropertyImplDecl * propImpl)606 PropertyImplStrategy::PropertyImplStrategy(CodeGenModule &CGM,
607                                      const ObjCPropertyImplDecl *propImpl) {
608   const ObjCPropertyDecl *prop = propImpl->getPropertyDecl();
609   ObjCPropertyDecl::SetterKind setterKind = prop->getSetterKind();
610 
611   IsCopy = (setterKind == ObjCPropertyDecl::Copy);
612   IsAtomic = prop->isAtomic();
613   HasStrong = false; // doesn't matter here.
614 
615   // Evaluate the ivar's size and alignment.
616   ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
617   QualType ivarType = ivar->getType();
618   std::tie(IvarSize, IvarAlignment) =
619       CGM.getContext().getTypeInfoInChars(ivarType);
620 
621   // If we have a copy property, we always have to use getProperty/setProperty.
622   // TODO: we could actually use setProperty and an expression for non-atomics.
623   if (IsCopy) {
624     Kind = GetSetProperty;
625     return;
626   }
627 
628   // Handle retain.
629   if (setterKind == ObjCPropertyDecl::Retain) {
630     // In GC-only, there's nothing special that needs to be done.
631     if (CGM.getLangOpts().getGC() == LangOptions::GCOnly) {
632       // fallthrough
633 
634     // In ARC, if the property is non-atomic, use expression emission,
635     // which translates to objc_storeStrong.  This isn't required, but
636     // it's slightly nicer.
637     } else if (CGM.getLangOpts().ObjCAutoRefCount && !IsAtomic) {
638       // Using standard expression emission for the setter is only
639       // acceptable if the ivar is __strong, which won't be true if
640       // the property is annotated with __attribute__((NSObject)).
641       // TODO: falling all the way back to objc_setProperty here is
642       // just laziness, though;  we could still use objc_storeStrong
643       // if we hacked it right.
644       if (ivarType.getObjCLifetime() == Qualifiers::OCL_Strong)
645         Kind = Expression;
646       else
647         Kind = SetPropertyAndExpressionGet;
648       return;
649 
650     // Otherwise, we need to at least use setProperty.  However, if
651     // the property isn't atomic, we can use normal expression
652     // emission for the getter.
653     } else if (!IsAtomic) {
654       Kind = SetPropertyAndExpressionGet;
655       return;
656 
657     // Otherwise, we have to use both setProperty and getProperty.
658     } else {
659       Kind = GetSetProperty;
660       return;
661     }
662   }
663 
664   // If we're not atomic, just use expression accesses.
665   if (!IsAtomic) {
666     Kind = Expression;
667     return;
668   }
669 
670   // Properties on bitfield ivars need to be emitted using expression
671   // accesses even if they're nominally atomic.
672   if (ivar->isBitField()) {
673     Kind = Expression;
674     return;
675   }
676 
677   // GC-qualified or ARC-qualified ivars need to be emitted as
678   // expressions.  This actually works out to being atomic anyway,
679   // except for ARC __strong, but that should trigger the above code.
680   if (ivarType.hasNonTrivialObjCLifetime() ||
681       (CGM.getLangOpts().getGC() &&
682        CGM.getContext().getObjCGCAttrKind(ivarType))) {
683     Kind = Expression;
684     return;
685   }
686 
687   // Compute whether the ivar has strong members.
688   if (CGM.getLangOpts().getGC())
689     if (const RecordType *recordType = ivarType->getAs<RecordType>())
690       HasStrong = recordType->getDecl()->hasObjectMember();
691 
692   // We can never access structs with object members with a native
693   // access, because we need to use write barriers.  This is what
694   // objc_copyStruct is for.
695   if (HasStrong) {
696     Kind = CopyStruct;
697     return;
698   }
699 
700   // Otherwise, this is target-dependent and based on the size and
701   // alignment of the ivar.
702 
703   // If the size of the ivar is not a power of two, give up.  We don't
704   // want to get into the business of doing compare-and-swaps.
705   if (!IvarSize.isPowerOfTwo()) {
706     Kind = CopyStruct;
707     return;
708   }
709 
710   llvm::Triple::ArchType arch =
711     CGM.getTarget().getTriple().getArch();
712 
713   // Most architectures require memory to fit within a single cache
714   // line, so the alignment has to be at least the size of the access.
715   // Otherwise we have to grab a lock.
716   if (IvarAlignment < IvarSize && !hasUnalignedAtomics(arch)) {
717     Kind = CopyStruct;
718     return;
719   }
720 
721   // If the ivar's size exceeds the architecture's maximum atomic
722   // access size, we have to use CopyStruct.
723   if (IvarSize > getMaxAtomicAccessSize(CGM, arch)) {
724     Kind = CopyStruct;
725     return;
726   }
727 
728   // Otherwise, we can use native loads and stores.
729   Kind = Native;
730 }
731 
732 /// \brief Generate an Objective-C property getter function.
733 ///
734 /// The given Decl must be an ObjCImplementationDecl. \@synthesize
735 /// is illegal within a category.
GenerateObjCGetter(ObjCImplementationDecl * IMP,const ObjCPropertyImplDecl * PID)736 void CodeGenFunction::GenerateObjCGetter(ObjCImplementationDecl *IMP,
737                                          const ObjCPropertyImplDecl *PID) {
738   llvm::Constant *AtomicHelperFn =
739       CodeGenFunction(CGM).GenerateObjCAtomicGetterCopyHelperFunction(PID);
740   const ObjCPropertyDecl *PD = PID->getPropertyDecl();
741   ObjCMethodDecl *OMD = PD->getGetterMethodDecl();
742   assert(OMD && "Invalid call to generate getter (empty method)");
743   StartObjCMethod(OMD, IMP->getClassInterface());
744 
745   generateObjCGetterBody(IMP, PID, OMD, AtomicHelperFn);
746 
747   FinishFunction();
748 }
749 
hasTrivialGetExpr(const ObjCPropertyImplDecl * propImpl)750 static bool hasTrivialGetExpr(const ObjCPropertyImplDecl *propImpl) {
751   const Expr *getter = propImpl->getGetterCXXConstructor();
752   if (!getter) return true;
753 
754   // Sema only makes only of these when the ivar has a C++ class type,
755   // so the form is pretty constrained.
756 
757   // If the property has a reference type, we might just be binding a
758   // reference, in which case the result will be a gl-value.  We should
759   // treat this as a non-trivial operation.
760   if (getter->isGLValue())
761     return false;
762 
763   // If we selected a trivial copy-constructor, we're okay.
764   if (const CXXConstructExpr *construct = dyn_cast<CXXConstructExpr>(getter))
765     return (construct->getConstructor()->isTrivial());
766 
767   // The constructor might require cleanups (in which case it's never
768   // trivial).
769   assert(isa<ExprWithCleanups>(getter));
770   return false;
771 }
772 
773 /// emitCPPObjectAtomicGetterCall - Call the runtime function to
774 /// copy the ivar into the resturn slot.
emitCPPObjectAtomicGetterCall(CodeGenFunction & CGF,llvm::Value * returnAddr,ObjCIvarDecl * ivar,llvm::Constant * AtomicHelperFn)775 static void emitCPPObjectAtomicGetterCall(CodeGenFunction &CGF,
776                                           llvm::Value *returnAddr,
777                                           ObjCIvarDecl *ivar,
778                                           llvm::Constant *AtomicHelperFn) {
779   // objc_copyCppObjectAtomic (&returnSlot, &CppObjectIvar,
780   //                           AtomicHelperFn);
781   CallArgList args;
782 
783   // The 1st argument is the return Slot.
784   args.add(RValue::get(returnAddr), CGF.getContext().VoidPtrTy);
785 
786   // The 2nd argument is the address of the ivar.
787   llvm::Value *ivarAddr =
788   CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(),
789                         CGF.LoadObjCSelf(), ivar, 0).getAddress();
790   ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
791   args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
792 
793   // Third argument is the helper function.
794   args.add(RValue::get(AtomicHelperFn), CGF.getContext().VoidPtrTy);
795 
796   llvm::Value *copyCppAtomicObjectFn =
797     CGF.CGM.getObjCRuntime().GetCppAtomicObjectGetFunction();
798   CGF.EmitCall(CGF.getTypes().arrangeFreeFunctionCall(CGF.getContext().VoidTy,
799                                                       args,
800                                                       FunctionType::ExtInfo(),
801                                                       RequiredArgs::All),
802                copyCppAtomicObjectFn, ReturnValueSlot(), args);
803 }
804 
805 void
generateObjCGetterBody(const ObjCImplementationDecl * classImpl,const ObjCPropertyImplDecl * propImpl,const ObjCMethodDecl * GetterMethodDecl,llvm::Constant * AtomicHelperFn)806 CodeGenFunction::generateObjCGetterBody(const ObjCImplementationDecl *classImpl,
807                                         const ObjCPropertyImplDecl *propImpl,
808                                         const ObjCMethodDecl *GetterMethodDecl,
809                                         llvm::Constant *AtomicHelperFn) {
810   // If there's a non-trivial 'get' expression, we just have to emit that.
811   if (!hasTrivialGetExpr(propImpl)) {
812     if (!AtomicHelperFn) {
813       ReturnStmt ret(SourceLocation(), propImpl->getGetterCXXConstructor(),
814                      /*nrvo*/ nullptr);
815       EmitReturnStmt(ret);
816     }
817     else {
818       ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
819       emitCPPObjectAtomicGetterCall(*this, ReturnValue,
820                                     ivar, AtomicHelperFn);
821     }
822     return;
823   }
824 
825   const ObjCPropertyDecl *prop = propImpl->getPropertyDecl();
826   QualType propType = prop->getType();
827   ObjCMethodDecl *getterMethod = prop->getGetterMethodDecl();
828 
829   ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
830 
831   // Pick an implementation strategy.
832   PropertyImplStrategy strategy(CGM, propImpl);
833   switch (strategy.getKind()) {
834   case PropertyImplStrategy::Native: {
835     // We don't need to do anything for a zero-size struct.
836     if (strategy.getIvarSize().isZero())
837       return;
838 
839     LValue LV = EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, 0);
840 
841     // Currently, all atomic accesses have to be through integer
842     // types, so there's no point in trying to pick a prettier type.
843     llvm::Type *bitcastType =
844       llvm::Type::getIntNTy(getLLVMContext(),
845                             getContext().toBits(strategy.getIvarSize()));
846     bitcastType = bitcastType->getPointerTo(); // addrspace 0 okay
847 
848     // Perform an atomic load.  This does not impose ordering constraints.
849     llvm::Value *ivarAddr = LV.getAddress();
850     ivarAddr = Builder.CreateBitCast(ivarAddr, bitcastType);
851     llvm::LoadInst *load = Builder.CreateLoad(ivarAddr, "load");
852     load->setAlignment(strategy.getIvarAlignment().getQuantity());
853     load->setAtomic(llvm::Unordered);
854 
855     // Store that value into the return address.  Doing this with a
856     // bitcast is likely to produce some pretty ugly IR, but it's not
857     // the *most* terrible thing in the world.
858     Builder.CreateStore(load, Builder.CreateBitCast(ReturnValue, bitcastType));
859 
860     // Make sure we don't do an autorelease.
861     AutoreleaseResult = false;
862     return;
863   }
864 
865   case PropertyImplStrategy::GetSetProperty: {
866     llvm::Value *getPropertyFn =
867       CGM.getObjCRuntime().GetPropertyGetFunction();
868     if (!getPropertyFn) {
869       CGM.ErrorUnsupported(propImpl, "Obj-C getter requiring atomic copy");
870       return;
871     }
872 
873     // Return (ivar-type) objc_getProperty((id) self, _cmd, offset, true).
874     // FIXME: Can't this be simpler? This might even be worse than the
875     // corresponding gcc code.
876     llvm::Value *cmd =
877       Builder.CreateLoad(LocalDeclMap[getterMethod->getCmdDecl()], "cmd");
878     llvm::Value *self = Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
879     llvm::Value *ivarOffset =
880       EmitIvarOffset(classImpl->getClassInterface(), ivar);
881 
882     CallArgList args;
883     args.add(RValue::get(self), getContext().getObjCIdType());
884     args.add(RValue::get(cmd), getContext().getObjCSelType());
885     args.add(RValue::get(ivarOffset), getContext().getPointerDiffType());
886     args.add(RValue::get(Builder.getInt1(strategy.isAtomic())),
887              getContext().BoolTy);
888 
889     // FIXME: We shouldn't need to get the function info here, the
890     // runtime already should have computed it to build the function.
891     llvm::Instruction *CallInstruction;
892     RValue RV = EmitCall(getTypes().arrangeFreeFunctionCall(propType, args,
893                                                        FunctionType::ExtInfo(),
894                                                             RequiredArgs::All),
895                          getPropertyFn, ReturnValueSlot(), args, nullptr,
896                          &CallInstruction);
897     if (llvm::CallInst *call = dyn_cast<llvm::CallInst>(CallInstruction))
898       call->setTailCall();
899 
900     // We need to fix the type here. Ivars with copy & retain are
901     // always objects so we don't need to worry about complex or
902     // aggregates.
903     RV = RValue::get(Builder.CreateBitCast(
904         RV.getScalarVal(),
905         getTypes().ConvertType(getterMethod->getReturnType())));
906 
907     EmitReturnOfRValue(RV, propType);
908 
909     // objc_getProperty does an autorelease, so we should suppress ours.
910     AutoreleaseResult = false;
911 
912     return;
913   }
914 
915   case PropertyImplStrategy::CopyStruct:
916     emitStructGetterCall(*this, ivar, strategy.isAtomic(),
917                          strategy.hasStrongMember());
918     return;
919 
920   case PropertyImplStrategy::Expression:
921   case PropertyImplStrategy::SetPropertyAndExpressionGet: {
922     LValue LV = EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, 0);
923 
924     QualType ivarType = ivar->getType();
925     switch (getEvaluationKind(ivarType)) {
926     case TEK_Complex: {
927       ComplexPairTy pair = EmitLoadOfComplex(LV, SourceLocation());
928       EmitStoreOfComplex(pair,
929                          MakeNaturalAlignAddrLValue(ReturnValue, ivarType),
930                          /*init*/ true);
931       return;
932     }
933     case TEK_Aggregate:
934       // The return value slot is guaranteed to not be aliased, but
935       // that's not necessarily the same as "on the stack", so
936       // we still potentially need objc_memmove_collectable.
937       EmitAggregateCopy(ReturnValue, LV.getAddress(), ivarType);
938       return;
939     case TEK_Scalar: {
940       llvm::Value *value;
941       if (propType->isReferenceType()) {
942         value = LV.getAddress();
943       } else {
944         // We want to load and autoreleaseReturnValue ARC __weak ivars.
945         if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak) {
946           value = emitARCRetainLoadOfScalar(*this, LV, ivarType);
947 
948         // Otherwise we want to do a simple load, suppressing the
949         // final autorelease.
950         } else {
951           value = EmitLoadOfLValue(LV, SourceLocation()).getScalarVal();
952           AutoreleaseResult = false;
953         }
954 
955         value = Builder.CreateBitCast(value, ConvertType(propType));
956         value = Builder.CreateBitCast(
957             value, ConvertType(GetterMethodDecl->getReturnType()));
958       }
959 
960       EmitReturnOfRValue(RValue::get(value), propType);
961       return;
962     }
963     }
964     llvm_unreachable("bad evaluation kind");
965   }
966 
967   }
968   llvm_unreachable("bad @property implementation strategy!");
969 }
970 
971 /// emitStructSetterCall - Call the runtime function to store the value
972 /// from the first formal parameter into the given ivar.
emitStructSetterCall(CodeGenFunction & CGF,ObjCMethodDecl * OMD,ObjCIvarDecl * ivar)973 static void emitStructSetterCall(CodeGenFunction &CGF, ObjCMethodDecl *OMD,
974                                  ObjCIvarDecl *ivar) {
975   // objc_copyStruct (&structIvar, &Arg,
976   //                  sizeof (struct something), true, false);
977   CallArgList args;
978 
979   // The first argument is the address of the ivar.
980   llvm::Value *ivarAddr = CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(),
981                                                 CGF.LoadObjCSelf(), ivar, 0)
982     .getAddress();
983   ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
984   args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
985 
986   // The second argument is the address of the parameter variable.
987   ParmVarDecl *argVar = *OMD->param_begin();
988   DeclRefExpr argRef(argVar, false, argVar->getType().getNonReferenceType(),
989                      VK_LValue, SourceLocation());
990   llvm::Value *argAddr = CGF.EmitLValue(&argRef).getAddress();
991   argAddr = CGF.Builder.CreateBitCast(argAddr, CGF.Int8PtrTy);
992   args.add(RValue::get(argAddr), CGF.getContext().VoidPtrTy);
993 
994   // The third argument is the sizeof the type.
995   llvm::Value *size =
996     CGF.CGM.getSize(CGF.getContext().getTypeSizeInChars(ivar->getType()));
997   args.add(RValue::get(size), CGF.getContext().getSizeType());
998 
999   // The fourth argument is the 'isAtomic' flag.
1000   args.add(RValue::get(CGF.Builder.getTrue()), CGF.getContext().BoolTy);
1001 
1002   // The fifth argument is the 'hasStrong' flag.
1003   // FIXME: should this really always be false?
1004   args.add(RValue::get(CGF.Builder.getFalse()), CGF.getContext().BoolTy);
1005 
1006   llvm::Value *copyStructFn = CGF.CGM.getObjCRuntime().GetSetStructFunction();
1007   CGF.EmitCall(CGF.getTypes().arrangeFreeFunctionCall(CGF.getContext().VoidTy,
1008                                                       args,
1009                                                       FunctionType::ExtInfo(),
1010                                                       RequiredArgs::All),
1011                copyStructFn, ReturnValueSlot(), args);
1012 }
1013 
1014 /// emitCPPObjectAtomicSetterCall - Call the runtime function to store
1015 /// the value from the first formal parameter into the given ivar, using
1016 /// the Cpp API for atomic Cpp objects with non-trivial copy assignment.
emitCPPObjectAtomicSetterCall(CodeGenFunction & CGF,ObjCMethodDecl * OMD,ObjCIvarDecl * ivar,llvm::Constant * AtomicHelperFn)1017 static void emitCPPObjectAtomicSetterCall(CodeGenFunction &CGF,
1018                                           ObjCMethodDecl *OMD,
1019                                           ObjCIvarDecl *ivar,
1020                                           llvm::Constant *AtomicHelperFn) {
1021   // objc_copyCppObjectAtomic (&CppObjectIvar, &Arg,
1022   //                           AtomicHelperFn);
1023   CallArgList args;
1024 
1025   // The first argument is the address of the ivar.
1026   llvm::Value *ivarAddr =
1027     CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(),
1028                           CGF.LoadObjCSelf(), ivar, 0).getAddress();
1029   ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
1030   args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
1031 
1032   // The second argument is the address of the parameter variable.
1033   ParmVarDecl *argVar = *OMD->param_begin();
1034   DeclRefExpr argRef(argVar, false, argVar->getType().getNonReferenceType(),
1035                      VK_LValue, SourceLocation());
1036   llvm::Value *argAddr = CGF.EmitLValue(&argRef).getAddress();
1037   argAddr = CGF.Builder.CreateBitCast(argAddr, CGF.Int8PtrTy);
1038   args.add(RValue::get(argAddr), CGF.getContext().VoidPtrTy);
1039 
1040   // Third argument is the helper function.
1041   args.add(RValue::get(AtomicHelperFn), CGF.getContext().VoidPtrTy);
1042 
1043   llvm::Value *copyCppAtomicObjectFn =
1044     CGF.CGM.getObjCRuntime().GetCppAtomicObjectSetFunction();
1045   CGF.EmitCall(CGF.getTypes().arrangeFreeFunctionCall(CGF.getContext().VoidTy,
1046                                                       args,
1047                                                       FunctionType::ExtInfo(),
1048                                                       RequiredArgs::All),
1049                copyCppAtomicObjectFn, ReturnValueSlot(), args);
1050 }
1051 
1052 
hasTrivialSetExpr(const ObjCPropertyImplDecl * PID)1053 static bool hasTrivialSetExpr(const ObjCPropertyImplDecl *PID) {
1054   Expr *setter = PID->getSetterCXXAssignment();
1055   if (!setter) return true;
1056 
1057   // Sema only makes only of these when the ivar has a C++ class type,
1058   // so the form is pretty constrained.
1059 
1060   // An operator call is trivial if the function it calls is trivial.
1061   // This also implies that there's nothing non-trivial going on with
1062   // the arguments, because operator= can only be trivial if it's a
1063   // synthesized assignment operator and therefore both parameters are
1064   // references.
1065   if (CallExpr *call = dyn_cast<CallExpr>(setter)) {
1066     if (const FunctionDecl *callee
1067           = dyn_cast_or_null<FunctionDecl>(call->getCalleeDecl()))
1068       if (callee->isTrivial())
1069         return true;
1070     return false;
1071   }
1072 
1073   assert(isa<ExprWithCleanups>(setter));
1074   return false;
1075 }
1076 
UseOptimizedSetter(CodeGenModule & CGM)1077 static bool UseOptimizedSetter(CodeGenModule &CGM) {
1078   if (CGM.getLangOpts().getGC() != LangOptions::NonGC)
1079     return false;
1080   return CGM.getLangOpts().ObjCRuntime.hasOptimizedSetter();
1081 }
1082 
1083 void
generateObjCSetterBody(const ObjCImplementationDecl * classImpl,const ObjCPropertyImplDecl * propImpl,llvm::Constant * AtomicHelperFn)1084 CodeGenFunction::generateObjCSetterBody(const ObjCImplementationDecl *classImpl,
1085                                         const ObjCPropertyImplDecl *propImpl,
1086                                         llvm::Constant *AtomicHelperFn) {
1087   const ObjCPropertyDecl *prop = propImpl->getPropertyDecl();
1088   ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
1089   ObjCMethodDecl *setterMethod = prop->getSetterMethodDecl();
1090 
1091   // Just use the setter expression if Sema gave us one and it's
1092   // non-trivial.
1093   if (!hasTrivialSetExpr(propImpl)) {
1094     if (!AtomicHelperFn)
1095       // If non-atomic, assignment is called directly.
1096       EmitStmt(propImpl->getSetterCXXAssignment());
1097     else
1098       // If atomic, assignment is called via a locking api.
1099       emitCPPObjectAtomicSetterCall(*this, setterMethod, ivar,
1100                                     AtomicHelperFn);
1101     return;
1102   }
1103 
1104   PropertyImplStrategy strategy(CGM, propImpl);
1105   switch (strategy.getKind()) {
1106   case PropertyImplStrategy::Native: {
1107     // We don't need to do anything for a zero-size struct.
1108     if (strategy.getIvarSize().isZero())
1109       return;
1110 
1111     llvm::Value *argAddr = LocalDeclMap[*setterMethod->param_begin()];
1112 
1113     LValue ivarLValue =
1114       EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, /*quals*/ 0);
1115     llvm::Value *ivarAddr = ivarLValue.getAddress();
1116 
1117     // Currently, all atomic accesses have to be through integer
1118     // types, so there's no point in trying to pick a prettier type.
1119     llvm::Type *bitcastType =
1120       llvm::Type::getIntNTy(getLLVMContext(),
1121                             getContext().toBits(strategy.getIvarSize()));
1122     bitcastType = bitcastType->getPointerTo(); // addrspace 0 okay
1123 
1124     // Cast both arguments to the chosen operation type.
1125     argAddr = Builder.CreateBitCast(argAddr, bitcastType);
1126     ivarAddr = Builder.CreateBitCast(ivarAddr, bitcastType);
1127 
1128     // This bitcast load is likely to cause some nasty IR.
1129     llvm::Value *load = Builder.CreateLoad(argAddr);
1130 
1131     // Perform an atomic store.  There are no memory ordering requirements.
1132     llvm::StoreInst *store = Builder.CreateStore(load, ivarAddr);
1133     store->setAlignment(strategy.getIvarAlignment().getQuantity());
1134     store->setAtomic(llvm::Unordered);
1135     return;
1136   }
1137 
1138   case PropertyImplStrategy::GetSetProperty:
1139   case PropertyImplStrategy::SetPropertyAndExpressionGet: {
1140 
1141     llvm::Value *setOptimizedPropertyFn = nullptr;
1142     llvm::Value *setPropertyFn = nullptr;
1143     if (UseOptimizedSetter(CGM)) {
1144       // 10.8 and iOS 6.0 code and GC is off
1145       setOptimizedPropertyFn =
1146         CGM.getObjCRuntime()
1147            .GetOptimizedPropertySetFunction(strategy.isAtomic(),
1148                                             strategy.isCopy());
1149       if (!setOptimizedPropertyFn) {
1150         CGM.ErrorUnsupported(propImpl, "Obj-C optimized setter - NYI");
1151         return;
1152       }
1153     }
1154     else {
1155       setPropertyFn = CGM.getObjCRuntime().GetPropertySetFunction();
1156       if (!setPropertyFn) {
1157         CGM.ErrorUnsupported(propImpl, "Obj-C setter requiring atomic copy");
1158         return;
1159       }
1160     }
1161 
1162     // Emit objc_setProperty((id) self, _cmd, offset, arg,
1163     //                       <is-atomic>, <is-copy>).
1164     llvm::Value *cmd =
1165       Builder.CreateLoad(LocalDeclMap[setterMethod->getCmdDecl()]);
1166     llvm::Value *self =
1167       Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
1168     llvm::Value *ivarOffset =
1169       EmitIvarOffset(classImpl->getClassInterface(), ivar);
1170     llvm::Value *arg = LocalDeclMap[*setterMethod->param_begin()];
1171     arg = Builder.CreateBitCast(Builder.CreateLoad(arg, "arg"), VoidPtrTy);
1172 
1173     CallArgList args;
1174     args.add(RValue::get(self), getContext().getObjCIdType());
1175     args.add(RValue::get(cmd), getContext().getObjCSelType());
1176     if (setOptimizedPropertyFn) {
1177       args.add(RValue::get(arg), getContext().getObjCIdType());
1178       args.add(RValue::get(ivarOffset), getContext().getPointerDiffType());
1179       EmitCall(getTypes().arrangeFreeFunctionCall(getContext().VoidTy, args,
1180                                                   FunctionType::ExtInfo(),
1181                                                   RequiredArgs::All),
1182                setOptimizedPropertyFn, ReturnValueSlot(), args);
1183     } else {
1184       args.add(RValue::get(ivarOffset), getContext().getPointerDiffType());
1185       args.add(RValue::get(arg), getContext().getObjCIdType());
1186       args.add(RValue::get(Builder.getInt1(strategy.isAtomic())),
1187                getContext().BoolTy);
1188       args.add(RValue::get(Builder.getInt1(strategy.isCopy())),
1189                getContext().BoolTy);
1190       // FIXME: We shouldn't need to get the function info here, the runtime
1191       // already should have computed it to build the function.
1192       EmitCall(getTypes().arrangeFreeFunctionCall(getContext().VoidTy, args,
1193                                                   FunctionType::ExtInfo(),
1194                                                   RequiredArgs::All),
1195                setPropertyFn, ReturnValueSlot(), args);
1196     }
1197 
1198     return;
1199   }
1200 
1201   case PropertyImplStrategy::CopyStruct:
1202     emitStructSetterCall(*this, setterMethod, ivar);
1203     return;
1204 
1205   case PropertyImplStrategy::Expression:
1206     break;
1207   }
1208 
1209   // Otherwise, fake up some ASTs and emit a normal assignment.
1210   ValueDecl *selfDecl = setterMethod->getSelfDecl();
1211   DeclRefExpr self(selfDecl, false, selfDecl->getType(),
1212                    VK_LValue, SourceLocation());
1213   ImplicitCastExpr selfLoad(ImplicitCastExpr::OnStack,
1214                             selfDecl->getType(), CK_LValueToRValue, &self,
1215                             VK_RValue);
1216   ObjCIvarRefExpr ivarRef(ivar, ivar->getType().getNonReferenceType(),
1217                           SourceLocation(), SourceLocation(),
1218                           &selfLoad, true, true);
1219 
1220   ParmVarDecl *argDecl = *setterMethod->param_begin();
1221   QualType argType = argDecl->getType().getNonReferenceType();
1222   DeclRefExpr arg(argDecl, false, argType, VK_LValue, SourceLocation());
1223   ImplicitCastExpr argLoad(ImplicitCastExpr::OnStack,
1224                            argType.getUnqualifiedType(), CK_LValueToRValue,
1225                            &arg, VK_RValue);
1226 
1227   // The property type can differ from the ivar type in some situations with
1228   // Objective-C pointer types, we can always bit cast the RHS in these cases.
1229   // The following absurdity is just to ensure well-formed IR.
1230   CastKind argCK = CK_NoOp;
1231   if (ivarRef.getType()->isObjCObjectPointerType()) {
1232     if (argLoad.getType()->isObjCObjectPointerType())
1233       argCK = CK_BitCast;
1234     else if (argLoad.getType()->isBlockPointerType())
1235       argCK = CK_BlockPointerToObjCPointerCast;
1236     else
1237       argCK = CK_CPointerToObjCPointerCast;
1238   } else if (ivarRef.getType()->isBlockPointerType()) {
1239      if (argLoad.getType()->isBlockPointerType())
1240       argCK = CK_BitCast;
1241     else
1242       argCK = CK_AnyPointerToBlockPointerCast;
1243   } else if (ivarRef.getType()->isPointerType()) {
1244     argCK = CK_BitCast;
1245   }
1246   ImplicitCastExpr argCast(ImplicitCastExpr::OnStack,
1247                            ivarRef.getType(), argCK, &argLoad,
1248                            VK_RValue);
1249   Expr *finalArg = &argLoad;
1250   if (!getContext().hasSameUnqualifiedType(ivarRef.getType(),
1251                                            argLoad.getType()))
1252     finalArg = &argCast;
1253 
1254 
1255   BinaryOperator assign(&ivarRef, finalArg, BO_Assign,
1256                         ivarRef.getType(), VK_RValue, OK_Ordinary,
1257                         SourceLocation(), false);
1258   EmitStmt(&assign);
1259 }
1260 
1261 /// \brief Generate an Objective-C property setter function.
1262 ///
1263 /// The given Decl must be an ObjCImplementationDecl. \@synthesize
1264 /// is illegal within a category.
GenerateObjCSetter(ObjCImplementationDecl * IMP,const ObjCPropertyImplDecl * PID)1265 void CodeGenFunction::GenerateObjCSetter(ObjCImplementationDecl *IMP,
1266                                          const ObjCPropertyImplDecl *PID) {
1267   llvm::Constant *AtomicHelperFn =
1268       CodeGenFunction(CGM).GenerateObjCAtomicSetterCopyHelperFunction(PID);
1269   const ObjCPropertyDecl *PD = PID->getPropertyDecl();
1270   ObjCMethodDecl *OMD = PD->getSetterMethodDecl();
1271   assert(OMD && "Invalid call to generate setter (empty method)");
1272   StartObjCMethod(OMD, IMP->getClassInterface());
1273 
1274   generateObjCSetterBody(IMP, PID, AtomicHelperFn);
1275 
1276   FinishFunction();
1277 }
1278 
1279 namespace {
1280   struct DestroyIvar : EHScopeStack::Cleanup {
1281   private:
1282     llvm::Value *addr;
1283     const ObjCIvarDecl *ivar;
1284     CodeGenFunction::Destroyer *destroyer;
1285     bool useEHCleanupForArray;
1286   public:
DestroyIvar__anon2e547c680311::DestroyIvar1287     DestroyIvar(llvm::Value *addr, const ObjCIvarDecl *ivar,
1288                 CodeGenFunction::Destroyer *destroyer,
1289                 bool useEHCleanupForArray)
1290       : addr(addr), ivar(ivar), destroyer(destroyer),
1291         useEHCleanupForArray(useEHCleanupForArray) {}
1292 
Emit__anon2e547c680311::DestroyIvar1293     void Emit(CodeGenFunction &CGF, Flags flags) override {
1294       LValue lvalue
1295         = CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), addr, ivar, /*CVR*/ 0);
1296       CGF.emitDestroy(lvalue.getAddress(), ivar->getType(), destroyer,
1297                       flags.isForNormalCleanup() && useEHCleanupForArray);
1298     }
1299   };
1300 }
1301 
1302 /// Like CodeGenFunction::destroyARCStrong, but do it with a call.
destroyARCStrongWithStore(CodeGenFunction & CGF,llvm::Value * addr,QualType type)1303 static void destroyARCStrongWithStore(CodeGenFunction &CGF,
1304                                       llvm::Value *addr,
1305                                       QualType type) {
1306   llvm::Value *null = getNullForVariable(addr);
1307   CGF.EmitARCStoreStrongCall(addr, null, /*ignored*/ true);
1308 }
1309 
emitCXXDestructMethod(CodeGenFunction & CGF,ObjCImplementationDecl * impl)1310 static void emitCXXDestructMethod(CodeGenFunction &CGF,
1311                                   ObjCImplementationDecl *impl) {
1312   CodeGenFunction::RunCleanupsScope scope(CGF);
1313 
1314   llvm::Value *self = CGF.LoadObjCSelf();
1315 
1316   const ObjCInterfaceDecl *iface = impl->getClassInterface();
1317   for (const ObjCIvarDecl *ivar = iface->all_declared_ivar_begin();
1318        ivar; ivar = ivar->getNextIvar()) {
1319     QualType type = ivar->getType();
1320 
1321     // Check whether the ivar is a destructible type.
1322     QualType::DestructionKind dtorKind = type.isDestructedType();
1323     if (!dtorKind) continue;
1324 
1325     CodeGenFunction::Destroyer *destroyer = nullptr;
1326 
1327     // Use a call to objc_storeStrong to destroy strong ivars, for the
1328     // general benefit of the tools.
1329     if (dtorKind == QualType::DK_objc_strong_lifetime) {
1330       destroyer = destroyARCStrongWithStore;
1331 
1332     // Otherwise use the default for the destruction kind.
1333     } else {
1334       destroyer = CGF.getDestroyer(dtorKind);
1335     }
1336 
1337     CleanupKind cleanupKind = CGF.getCleanupKind(dtorKind);
1338 
1339     CGF.EHStack.pushCleanup<DestroyIvar>(cleanupKind, self, ivar, destroyer,
1340                                          cleanupKind & EHCleanup);
1341   }
1342 
1343   assert(scope.requiresCleanups() && "nothing to do in .cxx_destruct?");
1344 }
1345 
GenerateObjCCtorDtorMethod(ObjCImplementationDecl * IMP,ObjCMethodDecl * MD,bool ctor)1346 void CodeGenFunction::GenerateObjCCtorDtorMethod(ObjCImplementationDecl *IMP,
1347                                                  ObjCMethodDecl *MD,
1348                                                  bool ctor) {
1349   MD->createImplicitParams(CGM.getContext(), IMP->getClassInterface());
1350   StartObjCMethod(MD, IMP->getClassInterface());
1351 
1352   // Emit .cxx_construct.
1353   if (ctor) {
1354     // Suppress the final autorelease in ARC.
1355     AutoreleaseResult = false;
1356 
1357     for (const auto *IvarInit : IMP->inits()) {
1358       FieldDecl *Field = IvarInit->getAnyMember();
1359       ObjCIvarDecl *Ivar = cast<ObjCIvarDecl>(Field);
1360       LValue LV = EmitLValueForIvar(TypeOfSelfObject(),
1361                                     LoadObjCSelf(), Ivar, 0);
1362       EmitAggExpr(IvarInit->getInit(),
1363                   AggValueSlot::forLValue(LV, AggValueSlot::IsDestructed,
1364                                           AggValueSlot::DoesNotNeedGCBarriers,
1365                                           AggValueSlot::IsNotAliased));
1366     }
1367     // constructor returns 'self'.
1368     CodeGenTypes &Types = CGM.getTypes();
1369     QualType IdTy(CGM.getContext().getObjCIdType());
1370     llvm::Value *SelfAsId =
1371       Builder.CreateBitCast(LoadObjCSelf(), Types.ConvertType(IdTy));
1372     EmitReturnOfRValue(RValue::get(SelfAsId), IdTy);
1373 
1374   // Emit .cxx_destruct.
1375   } else {
1376     emitCXXDestructMethod(*this, IMP);
1377   }
1378   FinishFunction();
1379 }
1380 
IndirectObjCSetterArg(const CGFunctionInfo & FI)1381 bool CodeGenFunction::IndirectObjCSetterArg(const CGFunctionInfo &FI) {
1382   CGFunctionInfo::const_arg_iterator it = FI.arg_begin();
1383   it++; it++;
1384   const ABIArgInfo &AI = it->info;
1385   // FIXME. Is this sufficient check?
1386   return (AI.getKind() == ABIArgInfo::Indirect);
1387 }
1388 
IvarTypeWithAggrGCObjects(QualType Ty)1389 bool CodeGenFunction::IvarTypeWithAggrGCObjects(QualType Ty) {
1390   if (CGM.getLangOpts().getGC() == LangOptions::NonGC)
1391     return false;
1392   if (const RecordType *FDTTy = Ty.getTypePtr()->getAs<RecordType>())
1393     return FDTTy->getDecl()->hasObjectMember();
1394   return false;
1395 }
1396 
LoadObjCSelf()1397 llvm::Value *CodeGenFunction::LoadObjCSelf() {
1398   VarDecl *Self = cast<ObjCMethodDecl>(CurFuncDecl)->getSelfDecl();
1399   DeclRefExpr DRE(Self, /*is enclosing local*/ (CurFuncDecl != CurCodeDecl),
1400                   Self->getType(), VK_LValue, SourceLocation());
1401   return EmitLoadOfScalar(EmitDeclRefLValue(&DRE), SourceLocation());
1402 }
1403 
TypeOfSelfObject()1404 QualType CodeGenFunction::TypeOfSelfObject() {
1405   const ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(CurFuncDecl);
1406   ImplicitParamDecl *selfDecl = OMD->getSelfDecl();
1407   const ObjCObjectPointerType *PTy = cast<ObjCObjectPointerType>(
1408     getContext().getCanonicalType(selfDecl->getType()));
1409   return PTy->getPointeeType();
1410 }
1411 
EmitObjCForCollectionStmt(const ObjCForCollectionStmt & S)1412 void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
1413   llvm::Constant *EnumerationMutationFn =
1414     CGM.getObjCRuntime().EnumerationMutationFunction();
1415 
1416   if (!EnumerationMutationFn) {
1417     CGM.ErrorUnsupported(&S, "Obj-C fast enumeration for this runtime");
1418     return;
1419   }
1420 
1421   CGDebugInfo *DI = getDebugInfo();
1422   if (DI)
1423     DI->EmitLexicalBlockStart(Builder, S.getSourceRange().getBegin());
1424 
1425   // The local variable comes into scope immediately.
1426   AutoVarEmission variable = AutoVarEmission::invalid();
1427   if (const DeclStmt *SD = dyn_cast<DeclStmt>(S.getElement()))
1428     variable = EmitAutoVarAlloca(*cast<VarDecl>(SD->getSingleDecl()));
1429 
1430   JumpDest LoopEnd = getJumpDestInCurrentScope("forcoll.end");
1431 
1432   // Fast enumeration state.
1433   QualType StateTy = CGM.getObjCFastEnumerationStateType();
1434   llvm::AllocaInst *StatePtr = CreateMemTemp(StateTy, "state.ptr");
1435   EmitNullInitialization(StatePtr, StateTy);
1436 
1437   // Number of elements in the items array.
1438   static const unsigned NumItems = 16;
1439 
1440   // Fetch the countByEnumeratingWithState:objects:count: selector.
1441   IdentifierInfo *II[] = {
1442     &CGM.getContext().Idents.get("countByEnumeratingWithState"),
1443     &CGM.getContext().Idents.get("objects"),
1444     &CGM.getContext().Idents.get("count")
1445   };
1446   Selector FastEnumSel =
1447     CGM.getContext().Selectors.getSelector(llvm::array_lengthof(II), &II[0]);
1448 
1449   QualType ItemsTy =
1450     getContext().getConstantArrayType(getContext().getObjCIdType(),
1451                                       llvm::APInt(32, NumItems),
1452                                       ArrayType::Normal, 0);
1453   llvm::Value *ItemsPtr = CreateMemTemp(ItemsTy, "items.ptr");
1454 
1455   // Emit the collection pointer.  In ARC, we do a retain.
1456   llvm::Value *Collection;
1457   if (getLangOpts().ObjCAutoRefCount) {
1458     Collection = EmitARCRetainScalarExpr(S.getCollection());
1459 
1460     // Enter a cleanup to do the release.
1461     EmitObjCConsumeObject(S.getCollection()->getType(), Collection);
1462   } else {
1463     Collection = EmitScalarExpr(S.getCollection());
1464   }
1465 
1466   // The 'continue' label needs to appear within the cleanup for the
1467   // collection object.
1468   JumpDest AfterBody = getJumpDestInCurrentScope("forcoll.next");
1469 
1470   // Send it our message:
1471   CallArgList Args;
1472 
1473   // The first argument is a temporary of the enumeration-state type.
1474   Args.add(RValue::get(StatePtr), getContext().getPointerType(StateTy));
1475 
1476   // The second argument is a temporary array with space for NumItems
1477   // pointers.  We'll actually be loading elements from the array
1478   // pointer written into the control state; this buffer is so that
1479   // collections that *aren't* backed by arrays can still queue up
1480   // batches of elements.
1481   Args.add(RValue::get(ItemsPtr), getContext().getPointerType(ItemsTy));
1482 
1483   // The third argument is the capacity of that temporary array.
1484   llvm::Type *UnsignedLongLTy = ConvertType(getContext().UnsignedLongTy);
1485   llvm::Constant *Count = llvm::ConstantInt::get(UnsignedLongLTy, NumItems);
1486   Args.add(RValue::get(Count), getContext().UnsignedLongTy);
1487 
1488   // Start the enumeration.
1489   RValue CountRV =
1490     CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
1491                                              getContext().UnsignedLongTy,
1492                                              FastEnumSel,
1493                                              Collection, Args);
1494 
1495   // The initial number of objects that were returned in the buffer.
1496   llvm::Value *initialBufferLimit = CountRV.getScalarVal();
1497 
1498   llvm::BasicBlock *EmptyBB = createBasicBlock("forcoll.empty");
1499   llvm::BasicBlock *LoopInitBB = createBasicBlock("forcoll.loopinit");
1500 
1501   llvm::Value *zero = llvm::Constant::getNullValue(UnsignedLongLTy);
1502 
1503   // If the limit pointer was zero to begin with, the collection is
1504   // empty; skip all this. Set the branch weight assuming this has the same
1505   // probability of exiting the loop as any other loop exit.
1506   uint64_t EntryCount = PGO.getCurrentRegionCount();
1507   RegionCounter Cnt = getPGORegionCounter(&S);
1508   Builder.CreateCondBr(Builder.CreateICmpEQ(initialBufferLimit, zero, "iszero"),
1509                        EmptyBB, LoopInitBB,
1510                        PGO.createBranchWeights(EntryCount, Cnt.getCount()));
1511 
1512   // Otherwise, initialize the loop.
1513   EmitBlock(LoopInitBB);
1514 
1515   // Save the initial mutations value.  This is the value at an
1516   // address that was written into the state object by
1517   // countByEnumeratingWithState:objects:count:.
1518   llvm::Value *StateMutationsPtrPtr = Builder.CreateStructGEP(
1519       StatePtr->getAllocatedType(), StatePtr, 2, "mutationsptr.ptr");
1520   llvm::Value *StateMutationsPtr = Builder.CreateLoad(StateMutationsPtrPtr,
1521                                                       "mutationsptr");
1522 
1523   llvm::Value *initialMutations =
1524     Builder.CreateLoad(StateMutationsPtr, "forcoll.initial-mutations");
1525 
1526   // Start looping.  This is the point we return to whenever we have a
1527   // fresh, non-empty batch of objects.
1528   llvm::BasicBlock *LoopBodyBB = createBasicBlock("forcoll.loopbody");
1529   EmitBlock(LoopBodyBB);
1530 
1531   // The current index into the buffer.
1532   llvm::PHINode *index = Builder.CreatePHI(UnsignedLongLTy, 3, "forcoll.index");
1533   index->addIncoming(zero, LoopInitBB);
1534 
1535   // The current buffer size.
1536   llvm::PHINode *count = Builder.CreatePHI(UnsignedLongLTy, 3, "forcoll.count");
1537   count->addIncoming(initialBufferLimit, LoopInitBB);
1538 
1539   Cnt.beginRegion(Builder);
1540 
1541   // Check whether the mutations value has changed from where it was
1542   // at start.  StateMutationsPtr should actually be invariant between
1543   // refreshes.
1544   StateMutationsPtr = Builder.CreateLoad(StateMutationsPtrPtr, "mutationsptr");
1545   llvm::Value *currentMutations
1546     = Builder.CreateLoad(StateMutationsPtr, "statemutations");
1547 
1548   llvm::BasicBlock *WasMutatedBB = createBasicBlock("forcoll.mutated");
1549   llvm::BasicBlock *WasNotMutatedBB = createBasicBlock("forcoll.notmutated");
1550 
1551   Builder.CreateCondBr(Builder.CreateICmpEQ(currentMutations, initialMutations),
1552                        WasNotMutatedBB, WasMutatedBB);
1553 
1554   // If so, call the enumeration-mutation function.
1555   EmitBlock(WasMutatedBB);
1556   llvm::Value *V =
1557     Builder.CreateBitCast(Collection,
1558                           ConvertType(getContext().getObjCIdType()));
1559   CallArgList Args2;
1560   Args2.add(RValue::get(V), getContext().getObjCIdType());
1561   // FIXME: We shouldn't need to get the function info here, the runtime already
1562   // should have computed it to build the function.
1563   EmitCall(CGM.getTypes().arrangeFreeFunctionCall(getContext().VoidTy, Args2,
1564                                                   FunctionType::ExtInfo(),
1565                                                   RequiredArgs::All),
1566            EnumerationMutationFn, ReturnValueSlot(), Args2);
1567 
1568   // Otherwise, or if the mutation function returns, just continue.
1569   EmitBlock(WasNotMutatedBB);
1570 
1571   // Initialize the element variable.
1572   RunCleanupsScope elementVariableScope(*this);
1573   bool elementIsVariable;
1574   LValue elementLValue;
1575   QualType elementType;
1576   if (const DeclStmt *SD = dyn_cast<DeclStmt>(S.getElement())) {
1577     // Initialize the variable, in case it's a __block variable or something.
1578     EmitAutoVarInit(variable);
1579 
1580     const VarDecl* D = cast<VarDecl>(SD->getSingleDecl());
1581     DeclRefExpr tempDRE(const_cast<VarDecl*>(D), false, D->getType(),
1582                         VK_LValue, SourceLocation());
1583     elementLValue = EmitLValue(&tempDRE);
1584     elementType = D->getType();
1585     elementIsVariable = true;
1586 
1587     if (D->isARCPseudoStrong())
1588       elementLValue.getQuals().setObjCLifetime(Qualifiers::OCL_ExplicitNone);
1589   } else {
1590     elementLValue = LValue(); // suppress warning
1591     elementType = cast<Expr>(S.getElement())->getType();
1592     elementIsVariable = false;
1593   }
1594   llvm::Type *convertedElementType = ConvertType(elementType);
1595 
1596   // Fetch the buffer out of the enumeration state.
1597   // TODO: this pointer should actually be invariant between
1598   // refreshes, which would help us do certain loop optimizations.
1599   llvm::Value *StateItemsPtr = Builder.CreateStructGEP(
1600       StatePtr->getAllocatedType(), StatePtr, 1, "stateitems.ptr");
1601   llvm::Value *EnumStateItems =
1602     Builder.CreateLoad(StateItemsPtr, "stateitems");
1603 
1604   // Fetch the value at the current index from the buffer.
1605   llvm::Value *CurrentItemPtr =
1606     Builder.CreateGEP(EnumStateItems, index, "currentitem.ptr");
1607   llvm::Value *CurrentItem = Builder.CreateLoad(CurrentItemPtr);
1608 
1609   // Cast that value to the right type.
1610   CurrentItem = Builder.CreateBitCast(CurrentItem, convertedElementType,
1611                                       "currentitem");
1612 
1613   // Make sure we have an l-value.  Yes, this gets evaluated every
1614   // time through the loop.
1615   if (!elementIsVariable) {
1616     elementLValue = EmitLValue(cast<Expr>(S.getElement()));
1617     EmitStoreThroughLValue(RValue::get(CurrentItem), elementLValue);
1618   } else {
1619     EmitScalarInit(CurrentItem, elementLValue);
1620   }
1621 
1622   // If we do have an element variable, this assignment is the end of
1623   // its initialization.
1624   if (elementIsVariable)
1625     EmitAutoVarCleanups(variable);
1626 
1627   // Perform the loop body, setting up break and continue labels.
1628   BreakContinueStack.push_back(BreakContinue(LoopEnd, AfterBody));
1629   {
1630     RunCleanupsScope Scope(*this);
1631     EmitStmt(S.getBody());
1632   }
1633   BreakContinueStack.pop_back();
1634 
1635   // Destroy the element variable now.
1636   elementVariableScope.ForceCleanup();
1637 
1638   // Check whether there are more elements.
1639   EmitBlock(AfterBody.getBlock());
1640 
1641   llvm::BasicBlock *FetchMoreBB = createBasicBlock("forcoll.refetch");
1642 
1643   // First we check in the local buffer.
1644   llvm::Value *indexPlusOne
1645     = Builder.CreateAdd(index, llvm::ConstantInt::get(UnsignedLongLTy, 1));
1646 
1647   // If we haven't overrun the buffer yet, we can continue.
1648   // Set the branch weights based on the simplifying assumption that this is
1649   // like a while-loop, i.e., ignoring that the false branch fetches more
1650   // elements and then returns to the loop.
1651   Builder.CreateCondBr(Builder.CreateICmpULT(indexPlusOne, count),
1652                        LoopBodyBB, FetchMoreBB,
1653                        PGO.createBranchWeights(Cnt.getCount(), EntryCount));
1654 
1655   index->addIncoming(indexPlusOne, AfterBody.getBlock());
1656   count->addIncoming(count, AfterBody.getBlock());
1657 
1658   // Otherwise, we have to fetch more elements.
1659   EmitBlock(FetchMoreBB);
1660 
1661   CountRV =
1662     CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
1663                                              getContext().UnsignedLongTy,
1664                                              FastEnumSel,
1665                                              Collection, Args);
1666 
1667   // If we got a zero count, we're done.
1668   llvm::Value *refetchCount = CountRV.getScalarVal();
1669 
1670   // (note that the message send might split FetchMoreBB)
1671   index->addIncoming(zero, Builder.GetInsertBlock());
1672   count->addIncoming(refetchCount, Builder.GetInsertBlock());
1673 
1674   Builder.CreateCondBr(Builder.CreateICmpEQ(refetchCount, zero),
1675                        EmptyBB, LoopBodyBB);
1676 
1677   // No more elements.
1678   EmitBlock(EmptyBB);
1679 
1680   if (!elementIsVariable) {
1681     // If the element was not a declaration, set it to be null.
1682 
1683     llvm::Value *null = llvm::Constant::getNullValue(convertedElementType);
1684     elementLValue = EmitLValue(cast<Expr>(S.getElement()));
1685     EmitStoreThroughLValue(RValue::get(null), elementLValue);
1686   }
1687 
1688   if (DI)
1689     DI->EmitLexicalBlockEnd(Builder, S.getSourceRange().getEnd());
1690 
1691   // Leave the cleanup we entered in ARC.
1692   if (getLangOpts().ObjCAutoRefCount)
1693     PopCleanupBlock();
1694 
1695   EmitBlock(LoopEnd.getBlock());
1696 }
1697 
EmitObjCAtTryStmt(const ObjCAtTryStmt & S)1698 void CodeGenFunction::EmitObjCAtTryStmt(const ObjCAtTryStmt &S) {
1699   CGM.getObjCRuntime().EmitTryStmt(*this, S);
1700 }
1701 
EmitObjCAtThrowStmt(const ObjCAtThrowStmt & S)1702 void CodeGenFunction::EmitObjCAtThrowStmt(const ObjCAtThrowStmt &S) {
1703   CGM.getObjCRuntime().EmitThrowStmt(*this, S);
1704 }
1705 
EmitObjCAtSynchronizedStmt(const ObjCAtSynchronizedStmt & S)1706 void CodeGenFunction::EmitObjCAtSynchronizedStmt(
1707                                               const ObjCAtSynchronizedStmt &S) {
1708   CGM.getObjCRuntime().EmitSynchronizedStmt(*this, S);
1709 }
1710 
1711 /// Produce the code for a CK_ARCProduceObject.  Just does a
1712 /// primitive retain.
EmitObjCProduceObject(QualType type,llvm::Value * value)1713 llvm::Value *CodeGenFunction::EmitObjCProduceObject(QualType type,
1714                                                     llvm::Value *value) {
1715   return EmitARCRetain(type, value);
1716 }
1717 
1718 namespace {
1719   struct CallObjCRelease : EHScopeStack::Cleanup {
CallObjCRelease__anon2e547c680411::CallObjCRelease1720     CallObjCRelease(llvm::Value *object) : object(object) {}
1721     llvm::Value *object;
1722 
Emit__anon2e547c680411::CallObjCRelease1723     void Emit(CodeGenFunction &CGF, Flags flags) override {
1724       // Releases at the end of the full-expression are imprecise.
1725       CGF.EmitARCRelease(object, ARCImpreciseLifetime);
1726     }
1727   };
1728 }
1729 
1730 /// Produce the code for a CK_ARCConsumeObject.  Does a primitive
1731 /// release at the end of the full-expression.
EmitObjCConsumeObject(QualType type,llvm::Value * object)1732 llvm::Value *CodeGenFunction::EmitObjCConsumeObject(QualType type,
1733                                                     llvm::Value *object) {
1734   // If we're in a conditional branch, we need to make the cleanup
1735   // conditional.
1736   pushFullExprCleanup<CallObjCRelease>(getARCCleanupKind(), object);
1737   return object;
1738 }
1739 
EmitObjCExtendObjectLifetime(QualType type,llvm::Value * value)1740 llvm::Value *CodeGenFunction::EmitObjCExtendObjectLifetime(QualType type,
1741                                                            llvm::Value *value) {
1742   return EmitARCRetainAutorelease(type, value);
1743 }
1744 
1745 /// Given a number of pointers, inform the optimizer that they're
1746 /// being intrinsically used up until this point in the program.
EmitARCIntrinsicUse(ArrayRef<llvm::Value * > values)1747 void CodeGenFunction::EmitARCIntrinsicUse(ArrayRef<llvm::Value*> values) {
1748   llvm::Constant *&fn = CGM.getARCEntrypoints().clang_arc_use;
1749   if (!fn) {
1750     llvm::FunctionType *fnType =
1751       llvm::FunctionType::get(CGM.VoidTy, None, true);
1752     fn = CGM.CreateRuntimeFunction(fnType, "clang.arc.use");
1753   }
1754 
1755   // This isn't really a "runtime" function, but as an intrinsic it
1756   // doesn't really matter as long as we align things up.
1757   EmitNounwindRuntimeCall(fn, values);
1758 }
1759 
1760 
createARCRuntimeFunction(CodeGenModule & CGM,llvm::FunctionType * type,StringRef fnName)1761 static llvm::Constant *createARCRuntimeFunction(CodeGenModule &CGM,
1762                                                 llvm::FunctionType *type,
1763                                                 StringRef fnName) {
1764   llvm::Constant *fn = CGM.CreateRuntimeFunction(type, fnName);
1765 
1766   if (llvm::Function *f = dyn_cast<llvm::Function>(fn)) {
1767     // If the target runtime doesn't naturally support ARC, emit weak
1768     // references to the runtime support library.  We don't really
1769     // permit this to fail, but we need a particular relocation style.
1770     if (!CGM.getLangOpts().ObjCRuntime.hasNativeARC()) {
1771       f->setLinkage(llvm::Function::ExternalWeakLinkage);
1772     } else if (fnName == "objc_retain" || fnName  == "objc_release") {
1773       // If we have Native ARC, set nonlazybind attribute for these APIs for
1774       // performance.
1775       f->addFnAttr(llvm::Attribute::NonLazyBind);
1776     }
1777   }
1778 
1779   return fn;
1780 }
1781 
1782 /// Perform an operation having the signature
1783 ///   i8* (i8*)
1784 /// 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)1785 static llvm::Value *emitARCValueOperation(CodeGenFunction &CGF,
1786                                           llvm::Value *value,
1787                                           llvm::Constant *&fn,
1788                                           StringRef fnName,
1789                                           bool isTailCall = false) {
1790   if (isa<llvm::ConstantPointerNull>(value)) return value;
1791 
1792   if (!fn) {
1793     llvm::FunctionType *fnType =
1794       llvm::FunctionType::get(CGF.Int8PtrTy, CGF.Int8PtrTy, false);
1795     fn = createARCRuntimeFunction(CGF.CGM, fnType, fnName);
1796   }
1797 
1798   // Cast the argument to 'id'.
1799   llvm::Type *origType = value->getType();
1800   value = CGF.Builder.CreateBitCast(value, CGF.Int8PtrTy);
1801 
1802   // Call the function.
1803   llvm::CallInst *call = CGF.EmitNounwindRuntimeCall(fn, value);
1804   if (isTailCall)
1805     call->setTailCall();
1806 
1807   // Cast the result back to the original type.
1808   return CGF.Builder.CreateBitCast(call, origType);
1809 }
1810 
1811 /// Perform an operation having the following signature:
1812 ///   i8* (i8**)
emitARCLoadOperation(CodeGenFunction & CGF,llvm::Value * addr,llvm::Constant * & fn,StringRef fnName)1813 static llvm::Value *emitARCLoadOperation(CodeGenFunction &CGF,
1814                                          llvm::Value *addr,
1815                                          llvm::Constant *&fn,
1816                                          StringRef fnName) {
1817   if (!fn) {
1818     llvm::FunctionType *fnType =
1819       llvm::FunctionType::get(CGF.Int8PtrTy, CGF.Int8PtrPtrTy, false);
1820     fn = createARCRuntimeFunction(CGF.CGM, fnType, fnName);
1821   }
1822 
1823   // Cast the argument to 'id*'.
1824   llvm::Type *origType = addr->getType();
1825   addr = CGF.Builder.CreateBitCast(addr, CGF.Int8PtrPtrTy);
1826 
1827   // Call the function.
1828   llvm::Value *result = CGF.EmitNounwindRuntimeCall(fn, addr);
1829 
1830   // Cast the result back to a dereference of the original type.
1831   if (origType != CGF.Int8PtrPtrTy)
1832     result = CGF.Builder.CreateBitCast(result,
1833                         cast<llvm::PointerType>(origType)->getElementType());
1834 
1835   return result;
1836 }
1837 
1838 /// Perform an operation having the following signature:
1839 ///   i8* (i8**, i8*)
emitARCStoreOperation(CodeGenFunction & CGF,llvm::Value * addr,llvm::Value * value,llvm::Constant * & fn,StringRef fnName,bool ignored)1840 static llvm::Value *emitARCStoreOperation(CodeGenFunction &CGF,
1841                                           llvm::Value *addr,
1842                                           llvm::Value *value,
1843                                           llvm::Constant *&fn,
1844                                           StringRef fnName,
1845                                           bool ignored) {
1846   assert(cast<llvm::PointerType>(addr->getType())->getElementType()
1847            == value->getType());
1848 
1849   if (!fn) {
1850     llvm::Type *argTypes[] = { CGF.Int8PtrPtrTy, CGF.Int8PtrTy };
1851 
1852     llvm::FunctionType *fnType
1853       = llvm::FunctionType::get(CGF.Int8PtrTy, argTypes, false);
1854     fn = createARCRuntimeFunction(CGF.CGM, fnType, fnName);
1855   }
1856 
1857   llvm::Type *origType = value->getType();
1858 
1859   llvm::Value *args[] = {
1860     CGF.Builder.CreateBitCast(addr, CGF.Int8PtrPtrTy),
1861     CGF.Builder.CreateBitCast(value, CGF.Int8PtrTy)
1862   };
1863   llvm::CallInst *result = CGF.EmitNounwindRuntimeCall(fn, args);
1864 
1865   if (ignored) return nullptr;
1866 
1867   return CGF.Builder.CreateBitCast(result, origType);
1868 }
1869 
1870 /// Perform an operation having the following signature:
1871 ///   void (i8**, i8**)
emitARCCopyOperation(CodeGenFunction & CGF,llvm::Value * dst,llvm::Value * src,llvm::Constant * & fn,StringRef fnName)1872 static void emitARCCopyOperation(CodeGenFunction &CGF,
1873                                  llvm::Value *dst,
1874                                  llvm::Value *src,
1875                                  llvm::Constant *&fn,
1876                                  StringRef fnName) {
1877   assert(dst->getType() == src->getType());
1878 
1879   if (!fn) {
1880     llvm::Type *argTypes[] = { CGF.Int8PtrPtrTy, CGF.Int8PtrPtrTy };
1881 
1882     llvm::FunctionType *fnType
1883       = llvm::FunctionType::get(CGF.Builder.getVoidTy(), argTypes, false);
1884     fn = createARCRuntimeFunction(CGF.CGM, fnType, fnName);
1885   }
1886 
1887   llvm::Value *args[] = {
1888     CGF.Builder.CreateBitCast(dst, CGF.Int8PtrPtrTy),
1889     CGF.Builder.CreateBitCast(src, CGF.Int8PtrPtrTy)
1890   };
1891   CGF.EmitNounwindRuntimeCall(fn, args);
1892 }
1893 
1894 /// Produce the code to do a retain.  Based on the type, calls one of:
1895 ///   call i8* \@objc_retain(i8* %value)
1896 ///   call i8* \@objc_retainBlock(i8* %value)
EmitARCRetain(QualType type,llvm::Value * value)1897 llvm::Value *CodeGenFunction::EmitARCRetain(QualType type, llvm::Value *value) {
1898   if (type->isBlockPointerType())
1899     return EmitARCRetainBlock(value, /*mandatory*/ false);
1900   else
1901     return EmitARCRetainNonBlock(value);
1902 }
1903 
1904 /// Retain the given object, with normal retain semantics.
1905 ///   call i8* \@objc_retain(i8* %value)
EmitARCRetainNonBlock(llvm::Value * value)1906 llvm::Value *CodeGenFunction::EmitARCRetainNonBlock(llvm::Value *value) {
1907   return emitARCValueOperation(*this, value,
1908                                CGM.getARCEntrypoints().objc_retain,
1909                                "objc_retain");
1910 }
1911 
1912 /// Retain the given block, with _Block_copy semantics.
1913 ///   call i8* \@objc_retainBlock(i8* %value)
1914 ///
1915 /// \param mandatory - If false, emit the call with metadata
1916 /// indicating that it's okay for the optimizer to eliminate this call
1917 /// if it can prove that the block never escapes except down the stack.
EmitARCRetainBlock(llvm::Value * value,bool mandatory)1918 llvm::Value *CodeGenFunction::EmitARCRetainBlock(llvm::Value *value,
1919                                                  bool mandatory) {
1920   llvm::Value *result
1921     = emitARCValueOperation(*this, value,
1922                             CGM.getARCEntrypoints().objc_retainBlock,
1923                             "objc_retainBlock");
1924 
1925   // If the copy isn't mandatory, add !clang.arc.copy_on_escape to
1926   // tell the optimizer that it doesn't need to do this copy if the
1927   // block doesn't escape, where being passed as an argument doesn't
1928   // count as escaping.
1929   if (!mandatory && isa<llvm::Instruction>(result)) {
1930     llvm::CallInst *call
1931       = cast<llvm::CallInst>(result->stripPointerCasts());
1932     assert(call->getCalledValue() == CGM.getARCEntrypoints().objc_retainBlock);
1933 
1934     call->setMetadata("clang.arc.copy_on_escape",
1935                       llvm::MDNode::get(Builder.getContext(), None));
1936   }
1937 
1938   return result;
1939 }
1940 
1941 /// Retain the given object which is the result of a function call.
1942 ///   call i8* \@objc_retainAutoreleasedReturnValue(i8* %value)
1943 ///
1944 /// Yes, this function name is one character away from a different
1945 /// call with completely different semantics.
1946 llvm::Value *
EmitARCRetainAutoreleasedReturnValue(llvm::Value * value)1947 CodeGenFunction::EmitARCRetainAutoreleasedReturnValue(llvm::Value *value) {
1948   // Fetch the void(void) inline asm which marks that we're going to
1949   // retain the autoreleased return value.
1950   llvm::InlineAsm *&marker
1951     = CGM.getARCEntrypoints().retainAutoreleasedReturnValueMarker;
1952   if (!marker) {
1953     StringRef assembly
1954       = CGM.getTargetCodeGenInfo()
1955            .getARCRetainAutoreleasedReturnValueMarker();
1956 
1957     // If we have an empty assembly string, there's nothing to do.
1958     if (assembly.empty()) {
1959 
1960     // Otherwise, at -O0, build an inline asm that we're going to call
1961     // in a moment.
1962     } else if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
1963       llvm::FunctionType *type =
1964         llvm::FunctionType::get(VoidTy, /*variadic*/false);
1965 
1966       marker = llvm::InlineAsm::get(type, assembly, "", /*sideeffects*/ true);
1967 
1968     // If we're at -O1 and above, we don't want to litter the code
1969     // with this marker yet, so leave a breadcrumb for the ARC
1970     // optimizer to pick up.
1971     } else {
1972       llvm::NamedMDNode *metadata =
1973         CGM.getModule().getOrInsertNamedMetadata(
1974                             "clang.arc.retainAutoreleasedReturnValueMarker");
1975       assert(metadata->getNumOperands() <= 1);
1976       if (metadata->getNumOperands() == 0) {
1977         metadata->addOperand(llvm::MDNode::get(
1978             getLLVMContext(), llvm::MDString::get(getLLVMContext(), assembly)));
1979       }
1980     }
1981   }
1982 
1983   // Call the marker asm if we made one, which we do only at -O0.
1984   if (marker) Builder.CreateCall(marker);
1985 
1986   return emitARCValueOperation(*this, value,
1987                      CGM.getARCEntrypoints().objc_retainAutoreleasedReturnValue,
1988                                "objc_retainAutoreleasedReturnValue");
1989 }
1990 
1991 /// Release the given object.
1992 ///   call void \@objc_release(i8* %value)
EmitARCRelease(llvm::Value * value,ARCPreciseLifetime_t precise)1993 void CodeGenFunction::EmitARCRelease(llvm::Value *value,
1994                                      ARCPreciseLifetime_t precise) {
1995   if (isa<llvm::ConstantPointerNull>(value)) return;
1996 
1997   llvm::Constant *&fn = CGM.getARCEntrypoints().objc_release;
1998   if (!fn) {
1999     llvm::FunctionType *fnType =
2000       llvm::FunctionType::get(Builder.getVoidTy(), Int8PtrTy, false);
2001     fn = createARCRuntimeFunction(CGM, fnType, "objc_release");
2002   }
2003 
2004   // Cast the argument to 'id'.
2005   value = Builder.CreateBitCast(value, Int8PtrTy);
2006 
2007   // Call objc_release.
2008   llvm::CallInst *call = EmitNounwindRuntimeCall(fn, value);
2009 
2010   if (precise == ARCImpreciseLifetime) {
2011     call->setMetadata("clang.imprecise_release",
2012                       llvm::MDNode::get(Builder.getContext(), None));
2013   }
2014 }
2015 
2016 /// Destroy a __strong variable.
2017 ///
2018 /// At -O0, emit a call to store 'null' into the address;
2019 /// instrumenting tools prefer this because the address is exposed,
2020 /// but it's relatively cumbersome to optimize.
2021 ///
2022 /// At -O1 and above, just load and call objc_release.
2023 ///
2024 ///   call void \@objc_storeStrong(i8** %addr, i8* null)
EmitARCDestroyStrong(llvm::Value * addr,ARCPreciseLifetime_t precise)2025 void CodeGenFunction::EmitARCDestroyStrong(llvm::Value *addr,
2026                                            ARCPreciseLifetime_t precise) {
2027   if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
2028     llvm::PointerType *addrTy = cast<llvm::PointerType>(addr->getType());
2029     llvm::Value *null = llvm::ConstantPointerNull::get(
2030                           cast<llvm::PointerType>(addrTy->getElementType()));
2031     EmitARCStoreStrongCall(addr, null, /*ignored*/ true);
2032     return;
2033   }
2034 
2035   llvm::Value *value = Builder.CreateLoad(addr);
2036   EmitARCRelease(value, precise);
2037 }
2038 
2039 /// Store into a strong object.  Always calls this:
2040 ///   call void \@objc_storeStrong(i8** %addr, i8* %value)
EmitARCStoreStrongCall(llvm::Value * addr,llvm::Value * value,bool ignored)2041 llvm::Value *CodeGenFunction::EmitARCStoreStrongCall(llvm::Value *addr,
2042                                                      llvm::Value *value,
2043                                                      bool ignored) {
2044   assert(cast<llvm::PointerType>(addr->getType())->getElementType()
2045            == value->getType());
2046 
2047   llvm::Constant *&fn = CGM.getARCEntrypoints().objc_storeStrong;
2048   if (!fn) {
2049     llvm::Type *argTypes[] = { Int8PtrPtrTy, Int8PtrTy };
2050     llvm::FunctionType *fnType
2051       = llvm::FunctionType::get(Builder.getVoidTy(), argTypes, false);
2052     fn = createARCRuntimeFunction(CGM, fnType, "objc_storeStrong");
2053   }
2054 
2055   llvm::Value *args[] = {
2056     Builder.CreateBitCast(addr, Int8PtrPtrTy),
2057     Builder.CreateBitCast(value, Int8PtrTy)
2058   };
2059   EmitNounwindRuntimeCall(fn, args);
2060 
2061   if (ignored) return nullptr;
2062   return value;
2063 }
2064 
2065 /// Store into a strong object.  Sometimes calls this:
2066 ///   call void \@objc_storeStrong(i8** %addr, i8* %value)
2067 /// Other times, breaks it down into components.
EmitARCStoreStrong(LValue dst,llvm::Value * newValue,bool ignored)2068 llvm::Value *CodeGenFunction::EmitARCStoreStrong(LValue dst,
2069                                                  llvm::Value *newValue,
2070                                                  bool ignored) {
2071   QualType type = dst.getType();
2072   bool isBlock = type->isBlockPointerType();
2073 
2074   // Use a store barrier at -O0 unless this is a block type or the
2075   // lvalue is inadequately aligned.
2076   if (shouldUseFusedARCCalls() &&
2077       !isBlock &&
2078       (dst.getAlignment().isZero() ||
2079        dst.getAlignment() >= CharUnits::fromQuantity(PointerAlignInBytes))) {
2080     return EmitARCStoreStrongCall(dst.getAddress(), newValue, ignored);
2081   }
2082 
2083   // Otherwise, split it out.
2084 
2085   // Retain the new value.
2086   newValue = EmitARCRetain(type, newValue);
2087 
2088   // Read the old value.
2089   llvm::Value *oldValue = EmitLoadOfScalar(dst, SourceLocation());
2090 
2091   // Store.  We do this before the release so that any deallocs won't
2092   // see the old value.
2093   EmitStoreOfScalar(newValue, dst);
2094 
2095   // Finally, release the old value.
2096   EmitARCRelease(oldValue, dst.isARCPreciseLifetime());
2097 
2098   return newValue;
2099 }
2100 
2101 /// Autorelease the given object.
2102 ///   call i8* \@objc_autorelease(i8* %value)
EmitARCAutorelease(llvm::Value * value)2103 llvm::Value *CodeGenFunction::EmitARCAutorelease(llvm::Value *value) {
2104   return emitARCValueOperation(*this, value,
2105                                CGM.getARCEntrypoints().objc_autorelease,
2106                                "objc_autorelease");
2107 }
2108 
2109 /// Autorelease the given object.
2110 ///   call i8* \@objc_autoreleaseReturnValue(i8* %value)
2111 llvm::Value *
EmitARCAutoreleaseReturnValue(llvm::Value * value)2112 CodeGenFunction::EmitARCAutoreleaseReturnValue(llvm::Value *value) {
2113   return emitARCValueOperation(*this, value,
2114                             CGM.getARCEntrypoints().objc_autoreleaseReturnValue,
2115                                "objc_autoreleaseReturnValue",
2116                                /*isTailCall*/ true);
2117 }
2118 
2119 /// Do a fused retain/autorelease of the given object.
2120 ///   call i8* \@objc_retainAutoreleaseReturnValue(i8* %value)
2121 llvm::Value *
EmitARCRetainAutoreleaseReturnValue(llvm::Value * value)2122 CodeGenFunction::EmitARCRetainAutoreleaseReturnValue(llvm::Value *value) {
2123   return emitARCValueOperation(*this, value,
2124                      CGM.getARCEntrypoints().objc_retainAutoreleaseReturnValue,
2125                                "objc_retainAutoreleaseReturnValue",
2126                                /*isTailCall*/ true);
2127 }
2128 
2129 /// Do a fused retain/autorelease of the given object.
2130 ///   call i8* \@objc_retainAutorelease(i8* %value)
2131 /// or
2132 ///   %retain = call i8* \@objc_retainBlock(i8* %value)
2133 ///   call i8* \@objc_autorelease(i8* %retain)
EmitARCRetainAutorelease(QualType type,llvm::Value * value)2134 llvm::Value *CodeGenFunction::EmitARCRetainAutorelease(QualType type,
2135                                                        llvm::Value *value) {
2136   if (!type->isBlockPointerType())
2137     return EmitARCRetainAutoreleaseNonBlock(value);
2138 
2139   if (isa<llvm::ConstantPointerNull>(value)) return value;
2140 
2141   llvm::Type *origType = value->getType();
2142   value = Builder.CreateBitCast(value, Int8PtrTy);
2143   value = EmitARCRetainBlock(value, /*mandatory*/ true);
2144   value = EmitARCAutorelease(value);
2145   return Builder.CreateBitCast(value, origType);
2146 }
2147 
2148 /// Do a fused retain/autorelease of the given object.
2149 ///   call i8* \@objc_retainAutorelease(i8* %value)
2150 llvm::Value *
EmitARCRetainAutoreleaseNonBlock(llvm::Value * value)2151 CodeGenFunction::EmitARCRetainAutoreleaseNonBlock(llvm::Value *value) {
2152   return emitARCValueOperation(*this, value,
2153                                CGM.getARCEntrypoints().objc_retainAutorelease,
2154                                "objc_retainAutorelease");
2155 }
2156 
2157 /// i8* \@objc_loadWeak(i8** %addr)
2158 /// Essentially objc_autorelease(objc_loadWeakRetained(addr)).
EmitARCLoadWeak(llvm::Value * addr)2159 llvm::Value *CodeGenFunction::EmitARCLoadWeak(llvm::Value *addr) {
2160   return emitARCLoadOperation(*this, addr,
2161                               CGM.getARCEntrypoints().objc_loadWeak,
2162                               "objc_loadWeak");
2163 }
2164 
2165 /// i8* \@objc_loadWeakRetained(i8** %addr)
EmitARCLoadWeakRetained(llvm::Value * addr)2166 llvm::Value *CodeGenFunction::EmitARCLoadWeakRetained(llvm::Value *addr) {
2167   return emitARCLoadOperation(*this, addr,
2168                               CGM.getARCEntrypoints().objc_loadWeakRetained,
2169                               "objc_loadWeakRetained");
2170 }
2171 
2172 /// i8* \@objc_storeWeak(i8** %addr, i8* %value)
2173 /// Returns %value.
EmitARCStoreWeak(llvm::Value * addr,llvm::Value * value,bool ignored)2174 llvm::Value *CodeGenFunction::EmitARCStoreWeak(llvm::Value *addr,
2175                                                llvm::Value *value,
2176                                                bool ignored) {
2177   return emitARCStoreOperation(*this, addr, value,
2178                                CGM.getARCEntrypoints().objc_storeWeak,
2179                                "objc_storeWeak", ignored);
2180 }
2181 
2182 /// i8* \@objc_initWeak(i8** %addr, i8* %value)
2183 /// Returns %value.  %addr is known to not have a current weak entry.
2184 /// Essentially equivalent to:
2185 ///   *addr = nil; objc_storeWeak(addr, value);
EmitARCInitWeak(llvm::Value * addr,llvm::Value * value)2186 void CodeGenFunction::EmitARCInitWeak(llvm::Value *addr, llvm::Value *value) {
2187   // If we're initializing to null, just write null to memory; no need
2188   // to get the runtime involved.  But don't do this if optimization
2189   // is enabled, because accounting for this would make the optimizer
2190   // much more complicated.
2191   if (isa<llvm::ConstantPointerNull>(value) &&
2192       CGM.getCodeGenOpts().OptimizationLevel == 0) {
2193     Builder.CreateStore(value, addr);
2194     return;
2195   }
2196 
2197   emitARCStoreOperation(*this, addr, value,
2198                         CGM.getARCEntrypoints().objc_initWeak,
2199                         "objc_initWeak", /*ignored*/ true);
2200 }
2201 
2202 /// void \@objc_destroyWeak(i8** %addr)
2203 /// Essentially objc_storeWeak(addr, nil).
EmitARCDestroyWeak(llvm::Value * addr)2204 void CodeGenFunction::EmitARCDestroyWeak(llvm::Value *addr) {
2205   llvm::Constant *&fn = CGM.getARCEntrypoints().objc_destroyWeak;
2206   if (!fn) {
2207     llvm::FunctionType *fnType =
2208       llvm::FunctionType::get(Builder.getVoidTy(), Int8PtrPtrTy, false);
2209     fn = createARCRuntimeFunction(CGM, fnType, "objc_destroyWeak");
2210   }
2211 
2212   // Cast the argument to 'id*'.
2213   addr = Builder.CreateBitCast(addr, Int8PtrPtrTy);
2214 
2215   EmitNounwindRuntimeCall(fn, addr);
2216 }
2217 
2218 /// void \@objc_moveWeak(i8** %dest, i8** %src)
2219 /// Disregards the current value in %dest.  Leaves %src pointing to nothing.
2220 /// Essentially (objc_copyWeak(dest, src), objc_destroyWeak(src)).
EmitARCMoveWeak(llvm::Value * dst,llvm::Value * src)2221 void CodeGenFunction::EmitARCMoveWeak(llvm::Value *dst, llvm::Value *src) {
2222   emitARCCopyOperation(*this, dst, src,
2223                        CGM.getARCEntrypoints().objc_moveWeak,
2224                        "objc_moveWeak");
2225 }
2226 
2227 /// void \@objc_copyWeak(i8** %dest, i8** %src)
2228 /// Disregards the current value in %dest.  Essentially
2229 ///   objc_release(objc_initWeak(dest, objc_readWeakRetained(src)))
EmitARCCopyWeak(llvm::Value * dst,llvm::Value * src)2230 void CodeGenFunction::EmitARCCopyWeak(llvm::Value *dst, llvm::Value *src) {
2231   emitARCCopyOperation(*this, dst, src,
2232                        CGM.getARCEntrypoints().objc_copyWeak,
2233                        "objc_copyWeak");
2234 }
2235 
2236 /// Produce the code to do a objc_autoreleasepool_push.
2237 ///   call i8* \@objc_autoreleasePoolPush(void)
EmitObjCAutoreleasePoolPush()2238 llvm::Value *CodeGenFunction::EmitObjCAutoreleasePoolPush() {
2239   llvm::Constant *&fn = CGM.getRREntrypoints().objc_autoreleasePoolPush;
2240   if (!fn) {
2241     llvm::FunctionType *fnType =
2242       llvm::FunctionType::get(Int8PtrTy, false);
2243     fn = createARCRuntimeFunction(CGM, fnType, "objc_autoreleasePoolPush");
2244   }
2245 
2246   return EmitNounwindRuntimeCall(fn);
2247 }
2248 
2249 /// Produce the code to do a primitive release.
2250 ///   call void \@objc_autoreleasePoolPop(i8* %ptr)
EmitObjCAutoreleasePoolPop(llvm::Value * value)2251 void CodeGenFunction::EmitObjCAutoreleasePoolPop(llvm::Value *value) {
2252   assert(value->getType() == Int8PtrTy);
2253 
2254   llvm::Constant *&fn = CGM.getRREntrypoints().objc_autoreleasePoolPop;
2255   if (!fn) {
2256     llvm::FunctionType *fnType =
2257       llvm::FunctionType::get(Builder.getVoidTy(), Int8PtrTy, false);
2258 
2259     // We don't want to use a weak import here; instead we should not
2260     // fall into this path.
2261     fn = createARCRuntimeFunction(CGM, fnType, "objc_autoreleasePoolPop");
2262   }
2263 
2264   // objc_autoreleasePoolPop can throw.
2265   EmitRuntimeCallOrInvoke(fn, value);
2266 }
2267 
2268 /// Produce the code to do an MRR version objc_autoreleasepool_push.
2269 /// Which is: [[NSAutoreleasePool alloc] init];
2270 /// Where alloc is declared as: + (id) alloc; in NSAutoreleasePool class.
2271 /// init is declared as: - (id) init; in its NSObject super class.
2272 ///
EmitObjCMRRAutoreleasePoolPush()2273 llvm::Value *CodeGenFunction::EmitObjCMRRAutoreleasePoolPush() {
2274   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
2275   llvm::Value *Receiver = Runtime.EmitNSAutoreleasePoolClassRef(*this);
2276   // [NSAutoreleasePool alloc]
2277   IdentifierInfo *II = &CGM.getContext().Idents.get("alloc");
2278   Selector AllocSel = getContext().Selectors.getSelector(0, &II);
2279   CallArgList Args;
2280   RValue AllocRV =
2281     Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
2282                                 getContext().getObjCIdType(),
2283                                 AllocSel, Receiver, Args);
2284 
2285   // [Receiver init]
2286   Receiver = AllocRV.getScalarVal();
2287   II = &CGM.getContext().Idents.get("init");
2288   Selector InitSel = getContext().Selectors.getSelector(0, &II);
2289   RValue InitRV =
2290     Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
2291                                 getContext().getObjCIdType(),
2292                                 InitSel, Receiver, Args);
2293   return InitRV.getScalarVal();
2294 }
2295 
2296 /// Produce the code to do a primitive release.
2297 /// [tmp drain];
EmitObjCMRRAutoreleasePoolPop(llvm::Value * Arg)2298 void CodeGenFunction::EmitObjCMRRAutoreleasePoolPop(llvm::Value *Arg) {
2299   IdentifierInfo *II = &CGM.getContext().Idents.get("drain");
2300   Selector DrainSel = getContext().Selectors.getSelector(0, &II);
2301   CallArgList Args;
2302   CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
2303                               getContext().VoidTy, DrainSel, Arg, Args);
2304 }
2305 
destroyARCStrongPrecise(CodeGenFunction & CGF,llvm::Value * addr,QualType type)2306 void CodeGenFunction::destroyARCStrongPrecise(CodeGenFunction &CGF,
2307                                               llvm::Value *addr,
2308                                               QualType type) {
2309   CGF.EmitARCDestroyStrong(addr, ARCPreciseLifetime);
2310 }
2311 
destroyARCStrongImprecise(CodeGenFunction & CGF,llvm::Value * addr,QualType type)2312 void CodeGenFunction::destroyARCStrongImprecise(CodeGenFunction &CGF,
2313                                                 llvm::Value *addr,
2314                                                 QualType type) {
2315   CGF.EmitARCDestroyStrong(addr, ARCImpreciseLifetime);
2316 }
2317 
destroyARCWeak(CodeGenFunction & CGF,llvm::Value * addr,QualType type)2318 void CodeGenFunction::destroyARCWeak(CodeGenFunction &CGF,
2319                                      llvm::Value *addr,
2320                                      QualType type) {
2321   CGF.EmitARCDestroyWeak(addr);
2322 }
2323 
2324 namespace {
2325   struct CallObjCAutoreleasePoolObject : EHScopeStack::Cleanup {
2326     llvm::Value *Token;
2327 
CallObjCAutoreleasePoolObject__anon2e547c680511::CallObjCAutoreleasePoolObject2328     CallObjCAutoreleasePoolObject(llvm::Value *token) : Token(token) {}
2329 
Emit__anon2e547c680511::CallObjCAutoreleasePoolObject2330     void Emit(CodeGenFunction &CGF, Flags flags) override {
2331       CGF.EmitObjCAutoreleasePoolPop(Token);
2332     }
2333   };
2334   struct CallObjCMRRAutoreleasePoolObject : EHScopeStack::Cleanup {
2335     llvm::Value *Token;
2336 
CallObjCMRRAutoreleasePoolObject__anon2e547c680511::CallObjCMRRAutoreleasePoolObject2337     CallObjCMRRAutoreleasePoolObject(llvm::Value *token) : Token(token) {}
2338 
Emit__anon2e547c680511::CallObjCMRRAutoreleasePoolObject2339     void Emit(CodeGenFunction &CGF, Flags flags) override {
2340       CGF.EmitObjCMRRAutoreleasePoolPop(Token);
2341     }
2342   };
2343 }
2344 
EmitObjCAutoreleasePoolCleanup(llvm::Value * Ptr)2345 void CodeGenFunction::EmitObjCAutoreleasePoolCleanup(llvm::Value *Ptr) {
2346   if (CGM.getLangOpts().ObjCAutoRefCount)
2347     EHStack.pushCleanup<CallObjCAutoreleasePoolObject>(NormalCleanup, Ptr);
2348   else
2349     EHStack.pushCleanup<CallObjCMRRAutoreleasePoolObject>(NormalCleanup, Ptr);
2350 }
2351 
tryEmitARCRetainLoadOfScalar(CodeGenFunction & CGF,LValue lvalue,QualType type)2352 static TryEmitResult tryEmitARCRetainLoadOfScalar(CodeGenFunction &CGF,
2353                                                   LValue lvalue,
2354                                                   QualType type) {
2355   switch (type.getObjCLifetime()) {
2356   case Qualifiers::OCL_None:
2357   case Qualifiers::OCL_ExplicitNone:
2358   case Qualifiers::OCL_Strong:
2359   case Qualifiers::OCL_Autoreleasing:
2360     return TryEmitResult(CGF.EmitLoadOfLValue(lvalue,
2361                                               SourceLocation()).getScalarVal(),
2362                          false);
2363 
2364   case Qualifiers::OCL_Weak:
2365     return TryEmitResult(CGF.EmitARCLoadWeakRetained(lvalue.getAddress()),
2366                          true);
2367   }
2368 
2369   llvm_unreachable("impossible lifetime!");
2370 }
2371 
tryEmitARCRetainLoadOfScalar(CodeGenFunction & CGF,const Expr * e)2372 static TryEmitResult tryEmitARCRetainLoadOfScalar(CodeGenFunction &CGF,
2373                                                   const Expr *e) {
2374   e = e->IgnoreParens();
2375   QualType type = e->getType();
2376 
2377   // If we're loading retained from a __strong xvalue, we can avoid
2378   // an extra retain/release pair by zeroing out the source of this
2379   // "move" operation.
2380   if (e->isXValue() &&
2381       !type.isConstQualified() &&
2382       type.getObjCLifetime() == Qualifiers::OCL_Strong) {
2383     // Emit the lvalue.
2384     LValue lv = CGF.EmitLValue(e);
2385 
2386     // Load the object pointer.
2387     llvm::Value *result = CGF.EmitLoadOfLValue(lv,
2388                                                SourceLocation()).getScalarVal();
2389 
2390     // Set the source pointer to NULL.
2391     CGF.EmitStoreOfScalar(getNullForVariable(lv.getAddress()), lv);
2392 
2393     return TryEmitResult(result, true);
2394   }
2395 
2396   // As a very special optimization, in ARC++, if the l-value is the
2397   // result of a non-volatile assignment, do a simple retain of the
2398   // result of the call to objc_storeWeak instead of reloading.
2399   if (CGF.getLangOpts().CPlusPlus &&
2400       !type.isVolatileQualified() &&
2401       type.getObjCLifetime() == Qualifiers::OCL_Weak &&
2402       isa<BinaryOperator>(e) &&
2403       cast<BinaryOperator>(e)->getOpcode() == BO_Assign)
2404     return TryEmitResult(CGF.EmitScalarExpr(e), false);
2405 
2406   return tryEmitARCRetainLoadOfScalar(CGF, CGF.EmitLValue(e), type);
2407 }
2408 
2409 static llvm::Value *emitARCRetainAfterCall(CodeGenFunction &CGF,
2410                                            llvm::Value *value);
2411 
2412 /// Given that the given expression is some sort of call (which does
2413 /// not return retained), emit a retain following it.
emitARCRetainCall(CodeGenFunction & CGF,const Expr * e)2414 static llvm::Value *emitARCRetainCall(CodeGenFunction &CGF, const Expr *e) {
2415   llvm::Value *value = CGF.EmitScalarExpr(e);
2416   return emitARCRetainAfterCall(CGF, value);
2417 }
2418 
emitARCRetainAfterCall(CodeGenFunction & CGF,llvm::Value * value)2419 static llvm::Value *emitARCRetainAfterCall(CodeGenFunction &CGF,
2420                                            llvm::Value *value) {
2421   if (llvm::CallInst *call = dyn_cast<llvm::CallInst>(value)) {
2422     CGBuilderTy::InsertPoint ip = CGF.Builder.saveIP();
2423 
2424     // Place the retain immediately following the call.
2425     CGF.Builder.SetInsertPoint(call->getParent(),
2426                                ++llvm::BasicBlock::iterator(call));
2427     value = CGF.EmitARCRetainAutoreleasedReturnValue(value);
2428 
2429     CGF.Builder.restoreIP(ip);
2430     return value;
2431   } else if (llvm::InvokeInst *invoke = dyn_cast<llvm::InvokeInst>(value)) {
2432     CGBuilderTy::InsertPoint ip = CGF.Builder.saveIP();
2433 
2434     // Place the retain at the beginning of the normal destination block.
2435     llvm::BasicBlock *BB = invoke->getNormalDest();
2436     CGF.Builder.SetInsertPoint(BB, BB->begin());
2437     value = CGF.EmitARCRetainAutoreleasedReturnValue(value);
2438 
2439     CGF.Builder.restoreIP(ip);
2440     return value;
2441 
2442   // Bitcasts can arise because of related-result returns.  Rewrite
2443   // the operand.
2444   } else if (llvm::BitCastInst *bitcast = dyn_cast<llvm::BitCastInst>(value)) {
2445     llvm::Value *operand = bitcast->getOperand(0);
2446     operand = emitARCRetainAfterCall(CGF, operand);
2447     bitcast->setOperand(0, operand);
2448     return bitcast;
2449 
2450   // Generic fall-back case.
2451   } else {
2452     // Retain using the non-block variant: we never need to do a copy
2453     // of a block that's been returned to us.
2454     return CGF.EmitARCRetainNonBlock(value);
2455   }
2456 }
2457 
2458 /// Determine whether it might be important to emit a separate
2459 /// objc_retain_block on the result of the given expression, or
2460 /// whether it's okay to just emit it in a +1 context.
shouldEmitSeparateBlockRetain(const Expr * e)2461 static bool shouldEmitSeparateBlockRetain(const Expr *e) {
2462   assert(e->getType()->isBlockPointerType());
2463   e = e->IgnoreParens();
2464 
2465   // For future goodness, emit block expressions directly in +1
2466   // contexts if we can.
2467   if (isa<BlockExpr>(e))
2468     return false;
2469 
2470   if (const CastExpr *cast = dyn_cast<CastExpr>(e)) {
2471     switch (cast->getCastKind()) {
2472     // Emitting these operations in +1 contexts is goodness.
2473     case CK_LValueToRValue:
2474     case CK_ARCReclaimReturnedObject:
2475     case CK_ARCConsumeObject:
2476     case CK_ARCProduceObject:
2477       return false;
2478 
2479     // These operations preserve a block type.
2480     case CK_NoOp:
2481     case CK_BitCast:
2482       return shouldEmitSeparateBlockRetain(cast->getSubExpr());
2483 
2484     // These operations are known to be bad (or haven't been considered).
2485     case CK_AnyPointerToBlockPointerCast:
2486     default:
2487       return true;
2488     }
2489   }
2490 
2491   return true;
2492 }
2493 
2494 /// Try to emit a PseudoObjectExpr at +1.
2495 ///
2496 /// This massively duplicates emitPseudoObjectRValue.
tryEmitARCRetainPseudoObject(CodeGenFunction & CGF,const PseudoObjectExpr * E)2497 static TryEmitResult tryEmitARCRetainPseudoObject(CodeGenFunction &CGF,
2498                                                   const PseudoObjectExpr *E) {
2499   SmallVector<CodeGenFunction::OpaqueValueMappingData, 4> opaques;
2500 
2501   // Find the result expression.
2502   const Expr *resultExpr = E->getResultExpr();
2503   assert(resultExpr);
2504   TryEmitResult result;
2505 
2506   for (PseudoObjectExpr::const_semantics_iterator
2507          i = E->semantics_begin(), e = E->semantics_end(); i != e; ++i) {
2508     const Expr *semantic = *i;
2509 
2510     // If this semantic expression is an opaque value, bind it
2511     // to the result of its source expression.
2512     if (const OpaqueValueExpr *ov = dyn_cast<OpaqueValueExpr>(semantic)) {
2513       typedef CodeGenFunction::OpaqueValueMappingData OVMA;
2514       OVMA opaqueData;
2515 
2516       // If this semantic is the result of the pseudo-object
2517       // expression, try to evaluate the source as +1.
2518       if (ov == resultExpr) {
2519         assert(!OVMA::shouldBindAsLValue(ov));
2520         result = tryEmitARCRetainScalarExpr(CGF, ov->getSourceExpr());
2521         opaqueData = OVMA::bind(CGF, ov, RValue::get(result.getPointer()));
2522 
2523       // Otherwise, just bind it.
2524       } else {
2525         opaqueData = OVMA::bind(CGF, ov, ov->getSourceExpr());
2526       }
2527       opaques.push_back(opaqueData);
2528 
2529     // Otherwise, if the expression is the result, evaluate it
2530     // and remember the result.
2531     } else if (semantic == resultExpr) {
2532       result = tryEmitARCRetainScalarExpr(CGF, semantic);
2533 
2534     // Otherwise, evaluate the expression in an ignored context.
2535     } else {
2536       CGF.EmitIgnoredExpr(semantic);
2537     }
2538   }
2539 
2540   // Unbind all the opaques now.
2541   for (unsigned i = 0, e = opaques.size(); i != e; ++i)
2542     opaques[i].unbind(CGF);
2543 
2544   return result;
2545 }
2546 
2547 static TryEmitResult
tryEmitARCRetainScalarExpr(CodeGenFunction & CGF,const Expr * e)2548 tryEmitARCRetainScalarExpr(CodeGenFunction &CGF, const Expr *e) {
2549   // We should *never* see a nested full-expression here, because if
2550   // we fail to emit at +1, our caller must not retain after we close
2551   // out the full-expression.
2552   assert(!isa<ExprWithCleanups>(e));
2553 
2554   // The desired result type, if it differs from the type of the
2555   // ultimate opaque expression.
2556   llvm::Type *resultType = nullptr;
2557 
2558   while (true) {
2559     e = e->IgnoreParens();
2560 
2561     // There's a break at the end of this if-chain;  anything
2562     // that wants to keep looping has to explicitly continue.
2563     if (const CastExpr *ce = dyn_cast<CastExpr>(e)) {
2564       switch (ce->getCastKind()) {
2565       // No-op casts don't change the type, so we just ignore them.
2566       case CK_NoOp:
2567         e = ce->getSubExpr();
2568         continue;
2569 
2570       case CK_LValueToRValue: {
2571         TryEmitResult loadResult
2572           = tryEmitARCRetainLoadOfScalar(CGF, ce->getSubExpr());
2573         if (resultType) {
2574           llvm::Value *value = loadResult.getPointer();
2575           value = CGF.Builder.CreateBitCast(value, resultType);
2576           loadResult.setPointer(value);
2577         }
2578         return loadResult;
2579       }
2580 
2581       // These casts can change the type, so remember that and
2582       // soldier on.  We only need to remember the outermost such
2583       // cast, though.
2584       case CK_CPointerToObjCPointerCast:
2585       case CK_BlockPointerToObjCPointerCast:
2586       case CK_AnyPointerToBlockPointerCast:
2587       case CK_BitCast:
2588         if (!resultType)
2589           resultType = CGF.ConvertType(ce->getType());
2590         e = ce->getSubExpr();
2591         assert(e->getType()->hasPointerRepresentation());
2592         continue;
2593 
2594       // For consumptions, just emit the subexpression and thus elide
2595       // the retain/release pair.
2596       case CK_ARCConsumeObject: {
2597         llvm::Value *result = CGF.EmitScalarExpr(ce->getSubExpr());
2598         if (resultType) result = CGF.Builder.CreateBitCast(result, resultType);
2599         return TryEmitResult(result, true);
2600       }
2601 
2602       // Block extends are net +0.  Naively, we could just recurse on
2603       // the subexpression, but actually we need to ensure that the
2604       // value is copied as a block, so there's a little filter here.
2605       case CK_ARCExtendBlockObject: {
2606         llvm::Value *result; // will be a +0 value
2607 
2608         // If we can't safely assume the sub-expression will produce a
2609         // block-copied value, emit the sub-expression at +0.
2610         if (shouldEmitSeparateBlockRetain(ce->getSubExpr())) {
2611           result = CGF.EmitScalarExpr(ce->getSubExpr());
2612 
2613         // Otherwise, try to emit the sub-expression at +1 recursively.
2614         } else {
2615           TryEmitResult subresult
2616             = tryEmitARCRetainScalarExpr(CGF, ce->getSubExpr());
2617           result = subresult.getPointer();
2618 
2619           // If that produced a retained value, just use that,
2620           // possibly casting down.
2621           if (subresult.getInt()) {
2622             if (resultType)
2623               result = CGF.Builder.CreateBitCast(result, resultType);
2624             return TryEmitResult(result, true);
2625           }
2626 
2627           // Otherwise it's +0.
2628         }
2629 
2630         // Retain the object as a block, then cast down.
2631         result = CGF.EmitARCRetainBlock(result, /*mandatory*/ true);
2632         if (resultType) result = CGF.Builder.CreateBitCast(result, resultType);
2633         return TryEmitResult(result, true);
2634       }
2635 
2636       // For reclaims, emit the subexpression as a retained call and
2637       // skip the consumption.
2638       case CK_ARCReclaimReturnedObject: {
2639         llvm::Value *result = emitARCRetainCall(CGF, ce->getSubExpr());
2640         if (resultType) result = CGF.Builder.CreateBitCast(result, resultType);
2641         return TryEmitResult(result, true);
2642       }
2643 
2644       default:
2645         break;
2646       }
2647 
2648     // Skip __extension__.
2649     } else if (const UnaryOperator *op = dyn_cast<UnaryOperator>(e)) {
2650       if (op->getOpcode() == UO_Extension) {
2651         e = op->getSubExpr();
2652         continue;
2653       }
2654 
2655     // For calls and message sends, use the retained-call logic.
2656     // Delegate inits are a special case in that they're the only
2657     // returns-retained expression that *isn't* surrounded by
2658     // a consume.
2659     } else if (isa<CallExpr>(e) ||
2660                (isa<ObjCMessageExpr>(e) &&
2661                 !cast<ObjCMessageExpr>(e)->isDelegateInitCall())) {
2662       llvm::Value *result = emitARCRetainCall(CGF, e);
2663       if (resultType) result = CGF.Builder.CreateBitCast(result, resultType);
2664       return TryEmitResult(result, true);
2665 
2666     // Look through pseudo-object expressions.
2667     } else if (const PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) {
2668       TryEmitResult result
2669         = tryEmitARCRetainPseudoObject(CGF, pseudo);
2670       if (resultType) {
2671         llvm::Value *value = result.getPointer();
2672         value = CGF.Builder.CreateBitCast(value, resultType);
2673         result.setPointer(value);
2674       }
2675       return result;
2676     }
2677 
2678     // Conservatively halt the search at any other expression kind.
2679     break;
2680   }
2681 
2682   // We didn't find an obvious production, so emit what we've got and
2683   // tell the caller that we didn't manage to retain.
2684   llvm::Value *result = CGF.EmitScalarExpr(e);
2685   if (resultType) result = CGF.Builder.CreateBitCast(result, resultType);
2686   return TryEmitResult(result, false);
2687 }
2688 
emitARCRetainLoadOfScalar(CodeGenFunction & CGF,LValue lvalue,QualType type)2689 static llvm::Value *emitARCRetainLoadOfScalar(CodeGenFunction &CGF,
2690                                                 LValue lvalue,
2691                                                 QualType type) {
2692   TryEmitResult result = tryEmitARCRetainLoadOfScalar(CGF, lvalue, type);
2693   llvm::Value *value = result.getPointer();
2694   if (!result.getInt())
2695     value = CGF.EmitARCRetain(type, value);
2696   return value;
2697 }
2698 
2699 /// EmitARCRetainScalarExpr - Semantically equivalent to
2700 /// EmitARCRetainObject(e->getType(), EmitScalarExpr(e)), but making a
2701 /// best-effort attempt to peephole expressions that naturally produce
2702 /// retained objects.
EmitARCRetainScalarExpr(const Expr * e)2703 llvm::Value *CodeGenFunction::EmitARCRetainScalarExpr(const Expr *e) {
2704   // The retain needs to happen within the full-expression.
2705   if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
2706     enterFullExpression(cleanups);
2707     RunCleanupsScope scope(*this);
2708     return EmitARCRetainScalarExpr(cleanups->getSubExpr());
2709   }
2710 
2711   TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e);
2712   llvm::Value *value = result.getPointer();
2713   if (!result.getInt())
2714     value = EmitARCRetain(e->getType(), value);
2715   return value;
2716 }
2717 
2718 llvm::Value *
EmitARCRetainAutoreleaseScalarExpr(const Expr * e)2719 CodeGenFunction::EmitARCRetainAutoreleaseScalarExpr(const Expr *e) {
2720   // The retain needs to happen within the full-expression.
2721   if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
2722     enterFullExpression(cleanups);
2723     RunCleanupsScope scope(*this);
2724     return EmitARCRetainAutoreleaseScalarExpr(cleanups->getSubExpr());
2725   }
2726 
2727   TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e);
2728   llvm::Value *value = result.getPointer();
2729   if (result.getInt())
2730     value = EmitARCAutorelease(value);
2731   else
2732     value = EmitARCRetainAutorelease(e->getType(), value);
2733   return value;
2734 }
2735 
EmitARCExtendBlockObject(const Expr * e)2736 llvm::Value *CodeGenFunction::EmitARCExtendBlockObject(const Expr *e) {
2737   llvm::Value *result;
2738   bool doRetain;
2739 
2740   if (shouldEmitSeparateBlockRetain(e)) {
2741     result = EmitScalarExpr(e);
2742     doRetain = true;
2743   } else {
2744     TryEmitResult subresult = tryEmitARCRetainScalarExpr(*this, e);
2745     result = subresult.getPointer();
2746     doRetain = !subresult.getInt();
2747   }
2748 
2749   if (doRetain)
2750     result = EmitARCRetainBlock(result, /*mandatory*/ true);
2751   return EmitObjCConsumeObject(e->getType(), result);
2752 }
2753 
EmitObjCThrowOperand(const Expr * expr)2754 llvm::Value *CodeGenFunction::EmitObjCThrowOperand(const Expr *expr) {
2755   // In ARC, retain and autorelease the expression.
2756   if (getLangOpts().ObjCAutoRefCount) {
2757     // Do so before running any cleanups for the full-expression.
2758     // EmitARCRetainAutoreleaseScalarExpr does this for us.
2759     return EmitARCRetainAutoreleaseScalarExpr(expr);
2760   }
2761 
2762   // Otherwise, use the normal scalar-expression emission.  The
2763   // exception machinery doesn't do anything special with the
2764   // exception like retaining it, so there's no safety associated with
2765   // only running cleanups after the throw has started, and when it
2766   // matters it tends to be substantially inferior code.
2767   return EmitScalarExpr(expr);
2768 }
2769 
2770 std::pair<LValue,llvm::Value*>
EmitARCStoreStrong(const BinaryOperator * e,bool ignored)2771 CodeGenFunction::EmitARCStoreStrong(const BinaryOperator *e,
2772                                     bool ignored) {
2773   // Evaluate the RHS first.
2774   TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e->getRHS());
2775   llvm::Value *value = result.getPointer();
2776 
2777   bool hasImmediateRetain = result.getInt();
2778 
2779   // If we didn't emit a retained object, and the l-value is of block
2780   // type, then we need to emit the block-retain immediately in case
2781   // it invalidates the l-value.
2782   if (!hasImmediateRetain && e->getType()->isBlockPointerType()) {
2783     value = EmitARCRetainBlock(value, /*mandatory*/ false);
2784     hasImmediateRetain = true;
2785   }
2786 
2787   LValue lvalue = EmitLValue(e->getLHS());
2788 
2789   // If the RHS was emitted retained, expand this.
2790   if (hasImmediateRetain) {
2791     llvm::Value *oldValue = EmitLoadOfScalar(lvalue, SourceLocation());
2792     EmitStoreOfScalar(value, lvalue);
2793     EmitARCRelease(oldValue, lvalue.isARCPreciseLifetime());
2794   } else {
2795     value = EmitARCStoreStrong(lvalue, value, ignored);
2796   }
2797 
2798   return std::pair<LValue,llvm::Value*>(lvalue, value);
2799 }
2800 
2801 std::pair<LValue,llvm::Value*>
EmitARCStoreAutoreleasing(const BinaryOperator * e)2802 CodeGenFunction::EmitARCStoreAutoreleasing(const BinaryOperator *e) {
2803   llvm::Value *value = EmitARCRetainAutoreleaseScalarExpr(e->getRHS());
2804   LValue lvalue = EmitLValue(e->getLHS());
2805 
2806   EmitStoreOfScalar(value, lvalue);
2807 
2808   return std::pair<LValue,llvm::Value*>(lvalue, value);
2809 }
2810 
EmitObjCAutoreleasePoolStmt(const ObjCAutoreleasePoolStmt & ARPS)2811 void CodeGenFunction::EmitObjCAutoreleasePoolStmt(
2812                                           const ObjCAutoreleasePoolStmt &ARPS) {
2813   const Stmt *subStmt = ARPS.getSubStmt();
2814   const CompoundStmt &S = cast<CompoundStmt>(*subStmt);
2815 
2816   CGDebugInfo *DI = getDebugInfo();
2817   if (DI)
2818     DI->EmitLexicalBlockStart(Builder, S.getLBracLoc());
2819 
2820   // Keep track of the current cleanup stack depth.
2821   RunCleanupsScope Scope(*this);
2822   if (CGM.getLangOpts().ObjCRuntime.hasNativeARC()) {
2823     llvm::Value *token = EmitObjCAutoreleasePoolPush();
2824     EHStack.pushCleanup<CallObjCAutoreleasePoolObject>(NormalCleanup, token);
2825   } else {
2826     llvm::Value *token = EmitObjCMRRAutoreleasePoolPush();
2827     EHStack.pushCleanup<CallObjCMRRAutoreleasePoolObject>(NormalCleanup, token);
2828   }
2829 
2830   for (const auto *I : S.body())
2831     EmitStmt(I);
2832 
2833   if (DI)
2834     DI->EmitLexicalBlockEnd(Builder, S.getRBracLoc());
2835 }
2836 
2837 /// EmitExtendGCLifetime - Given a pointer to an Objective-C object,
2838 /// make sure it survives garbage collection until this point.
EmitExtendGCLifetime(llvm::Value * object)2839 void CodeGenFunction::EmitExtendGCLifetime(llvm::Value *object) {
2840   // We just use an inline assembly.
2841   llvm::FunctionType *extenderType
2842     = llvm::FunctionType::get(VoidTy, VoidPtrTy, RequiredArgs::All);
2843   llvm::Value *extender
2844     = llvm::InlineAsm::get(extenderType,
2845                            /* assembly */ "",
2846                            /* constraints */ "r",
2847                            /* side effects */ true);
2848 
2849   object = Builder.CreateBitCast(object, VoidPtrTy);
2850   EmitNounwindRuntimeCall(extender, object);
2851 }
2852 
2853 /// GenerateObjCAtomicSetterCopyHelperFunction - Given a c++ object type with
2854 /// non-trivial copy assignment function, produce following helper function.
2855 /// static void copyHelper(Ty *dest, const Ty *source) { *dest = *source; }
2856 ///
2857 llvm::Constant *
GenerateObjCAtomicSetterCopyHelperFunction(const ObjCPropertyImplDecl * PID)2858 CodeGenFunction::GenerateObjCAtomicSetterCopyHelperFunction(
2859                                         const ObjCPropertyImplDecl *PID) {
2860   if (!getLangOpts().CPlusPlus ||
2861       !getLangOpts().ObjCRuntime.hasAtomicCopyHelper())
2862     return nullptr;
2863   QualType Ty = PID->getPropertyIvarDecl()->getType();
2864   if (!Ty->isRecordType())
2865     return nullptr;
2866   const ObjCPropertyDecl *PD = PID->getPropertyDecl();
2867   if ((!(PD->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_atomic)))
2868     return nullptr;
2869   llvm::Constant *HelperFn = nullptr;
2870   if (hasTrivialSetExpr(PID))
2871     return nullptr;
2872   assert(PID->getSetterCXXAssignment() && "SetterCXXAssignment - null");
2873   if ((HelperFn = CGM.getAtomicSetterHelperFnMap(Ty)))
2874     return HelperFn;
2875 
2876   ASTContext &C = getContext();
2877   IdentifierInfo *II
2878     = &CGM.getContext().Idents.get("__assign_helper_atomic_property_");
2879   FunctionDecl *FD = FunctionDecl::Create(C,
2880                                           C.getTranslationUnitDecl(),
2881                                           SourceLocation(),
2882                                           SourceLocation(), II, C.VoidTy,
2883                                           nullptr, SC_Static,
2884                                           false,
2885                                           false);
2886 
2887   QualType DestTy = C.getPointerType(Ty);
2888   QualType SrcTy = Ty;
2889   SrcTy.addConst();
2890   SrcTy = C.getPointerType(SrcTy);
2891 
2892   FunctionArgList args;
2893   ImplicitParamDecl dstDecl(getContext(), FD, SourceLocation(), nullptr,DestTy);
2894   args.push_back(&dstDecl);
2895   ImplicitParamDecl srcDecl(getContext(), FD, SourceLocation(), nullptr, SrcTy);
2896   args.push_back(&srcDecl);
2897 
2898   const CGFunctionInfo &FI = CGM.getTypes().arrangeFreeFunctionDeclaration(
2899       C.VoidTy, args, FunctionType::ExtInfo(), RequiredArgs::All);
2900 
2901   llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
2902 
2903   llvm::Function *Fn =
2904     llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
2905                            "__assign_helper_atomic_property_",
2906                            &CGM.getModule());
2907 
2908   StartFunction(FD, C.VoidTy, Fn, FI, args);
2909 
2910   DeclRefExpr DstExpr(&dstDecl, false, DestTy,
2911                       VK_RValue, SourceLocation());
2912   UnaryOperator DST(&DstExpr, UO_Deref, DestTy->getPointeeType(),
2913                     VK_LValue, OK_Ordinary, SourceLocation());
2914 
2915   DeclRefExpr SrcExpr(&srcDecl, false, SrcTy,
2916                       VK_RValue, SourceLocation());
2917   UnaryOperator SRC(&SrcExpr, UO_Deref, SrcTy->getPointeeType(),
2918                     VK_LValue, OK_Ordinary, SourceLocation());
2919 
2920   Expr *Args[2] = { &DST, &SRC };
2921   CallExpr *CalleeExp = cast<CallExpr>(PID->getSetterCXXAssignment());
2922   CXXOperatorCallExpr TheCall(C, OO_Equal, CalleeExp->getCallee(),
2923                               Args, DestTy->getPointeeType(),
2924                               VK_LValue, SourceLocation(), false);
2925 
2926   EmitStmt(&TheCall);
2927 
2928   FinishFunction();
2929   HelperFn = llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
2930   CGM.setAtomicSetterHelperFnMap(Ty, HelperFn);
2931   return HelperFn;
2932 }
2933 
2934 llvm::Constant *
GenerateObjCAtomicGetterCopyHelperFunction(const ObjCPropertyImplDecl * PID)2935 CodeGenFunction::GenerateObjCAtomicGetterCopyHelperFunction(
2936                                             const ObjCPropertyImplDecl *PID) {
2937   if (!getLangOpts().CPlusPlus ||
2938       !getLangOpts().ObjCRuntime.hasAtomicCopyHelper())
2939     return nullptr;
2940   const ObjCPropertyDecl *PD = PID->getPropertyDecl();
2941   QualType Ty = PD->getType();
2942   if (!Ty->isRecordType())
2943     return nullptr;
2944   if ((!(PD->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_atomic)))
2945     return nullptr;
2946   llvm::Constant *HelperFn = nullptr;
2947 
2948   if (hasTrivialGetExpr(PID))
2949     return nullptr;
2950   assert(PID->getGetterCXXConstructor() && "getGetterCXXConstructor - null");
2951   if ((HelperFn = CGM.getAtomicGetterHelperFnMap(Ty)))
2952     return HelperFn;
2953 
2954 
2955   ASTContext &C = getContext();
2956   IdentifierInfo *II
2957   = &CGM.getContext().Idents.get("__copy_helper_atomic_property_");
2958   FunctionDecl *FD = FunctionDecl::Create(C,
2959                                           C.getTranslationUnitDecl(),
2960                                           SourceLocation(),
2961                                           SourceLocation(), II, C.VoidTy,
2962                                           nullptr, SC_Static,
2963                                           false,
2964                                           false);
2965 
2966   QualType DestTy = C.getPointerType(Ty);
2967   QualType SrcTy = Ty;
2968   SrcTy.addConst();
2969   SrcTy = C.getPointerType(SrcTy);
2970 
2971   FunctionArgList args;
2972   ImplicitParamDecl dstDecl(getContext(), FD, SourceLocation(), nullptr,DestTy);
2973   args.push_back(&dstDecl);
2974   ImplicitParamDecl srcDecl(getContext(), FD, SourceLocation(), nullptr, SrcTy);
2975   args.push_back(&srcDecl);
2976 
2977   const CGFunctionInfo &FI = CGM.getTypes().arrangeFreeFunctionDeclaration(
2978       C.VoidTy, args, FunctionType::ExtInfo(), RequiredArgs::All);
2979 
2980   llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
2981 
2982   llvm::Function *Fn =
2983   llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
2984                          "__copy_helper_atomic_property_", &CGM.getModule());
2985 
2986   StartFunction(FD, C.VoidTy, Fn, FI, args);
2987 
2988   DeclRefExpr SrcExpr(&srcDecl, false, SrcTy,
2989                       VK_RValue, SourceLocation());
2990 
2991   UnaryOperator SRC(&SrcExpr, UO_Deref, SrcTy->getPointeeType(),
2992                     VK_LValue, OK_Ordinary, SourceLocation());
2993 
2994   CXXConstructExpr *CXXConstExpr =
2995     cast<CXXConstructExpr>(PID->getGetterCXXConstructor());
2996 
2997   SmallVector<Expr*, 4> ConstructorArgs;
2998   ConstructorArgs.push_back(&SRC);
2999   CXXConstructExpr::arg_iterator A = CXXConstExpr->arg_begin();
3000   ++A;
3001 
3002   for (CXXConstructExpr::arg_iterator AEnd = CXXConstExpr->arg_end();
3003        A != AEnd; ++A)
3004     ConstructorArgs.push_back(*A);
3005 
3006   CXXConstructExpr *TheCXXConstructExpr =
3007     CXXConstructExpr::Create(C, Ty, SourceLocation(),
3008                              CXXConstExpr->getConstructor(),
3009                              CXXConstExpr->isElidable(),
3010                              ConstructorArgs,
3011                              CXXConstExpr->hadMultipleCandidates(),
3012                              CXXConstExpr->isListInitialization(),
3013                              CXXConstExpr->isStdInitListInitialization(),
3014                              CXXConstExpr->requiresZeroInitialization(),
3015                              CXXConstExpr->getConstructionKind(),
3016                              SourceRange());
3017 
3018   DeclRefExpr DstExpr(&dstDecl, false, DestTy,
3019                       VK_RValue, SourceLocation());
3020 
3021   RValue DV = EmitAnyExpr(&DstExpr);
3022   CharUnits Alignment
3023     = getContext().getTypeAlignInChars(TheCXXConstructExpr->getType());
3024   EmitAggExpr(TheCXXConstructExpr,
3025               AggValueSlot::forAddr(DV.getScalarVal(), Alignment, Qualifiers(),
3026                                     AggValueSlot::IsDestructed,
3027                                     AggValueSlot::DoesNotNeedGCBarriers,
3028                                     AggValueSlot::IsNotAliased));
3029 
3030   FinishFunction();
3031   HelperFn = llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
3032   CGM.setAtomicGetterHelperFnMap(Ty, HelperFn);
3033   return HelperFn;
3034 }
3035 
3036 llvm::Value *
EmitBlockCopyAndAutorelease(llvm::Value * Block,QualType Ty)3037 CodeGenFunction::EmitBlockCopyAndAutorelease(llvm::Value *Block, QualType Ty) {
3038   // Get selectors for retain/autorelease.
3039   IdentifierInfo *CopyID = &getContext().Idents.get("copy");
3040   Selector CopySelector =
3041       getContext().Selectors.getNullarySelector(CopyID);
3042   IdentifierInfo *AutoreleaseID = &getContext().Idents.get("autorelease");
3043   Selector AutoreleaseSelector =
3044       getContext().Selectors.getNullarySelector(AutoreleaseID);
3045 
3046   // Emit calls to retain/autorelease.
3047   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
3048   llvm::Value *Val = Block;
3049   RValue Result;
3050   Result = Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
3051                                        Ty, CopySelector,
3052                                        Val, CallArgList(), nullptr, nullptr);
3053   Val = Result.getScalarVal();
3054   Result = Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
3055                                        Ty, AutoreleaseSelector,
3056                                        Val, CallArgList(), nullptr, nullptr);
3057   Val = Result.getScalarVal();
3058   return Val;
3059 }
3060 
3061 
~CGObjCRuntime()3062 CGObjCRuntime::~CGObjCRuntime() {}
3063