xref: /freebsd/contrib/llvm-project/clang/lib/CodeGen/CGObjC.cpp (revision 517e52b6c21ccff22c46df0dcd15c19baee3d86c)
1 //===---- CGObjC.cpp - Emit LLVM Code for Objective-C ---------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This contains code to emit Objective-C code as LLVM code.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "CGDebugInfo.h"
14 #include "CGObjCRuntime.h"
15 #include "CodeGenFunction.h"
16 #include "CodeGenModule.h"
17 #include "ConstantEmitter.h"
18 #include "TargetInfo.h"
19 #include "clang/AST/ASTContext.h"
20 #include "clang/AST/Attr.h"
21 #include "clang/AST/DeclObjC.h"
22 #include "clang/AST/StmtObjC.h"
23 #include "clang/Basic/Diagnostic.h"
24 #include "clang/CodeGen/CGFunctionInfo.h"
25 #include "llvm/ADT/STLExtras.h"
26 #include "llvm/BinaryFormat/MachO.h"
27 #include "llvm/IR/DataLayout.h"
28 #include "llvm/IR/InlineAsm.h"
29 using namespace clang;
30 using namespace CodeGen;
31 
32 typedef llvm::PointerIntPair<llvm::Value*,1,bool> TryEmitResult;
33 static TryEmitResult
34 tryEmitARCRetainScalarExpr(CodeGenFunction &CGF, const Expr *e);
35 static RValue AdjustObjCObjectType(CodeGenFunction &CGF,
36                                    QualType ET,
37                                    RValue Result);
38 
39 /// Given the address of a variable of pointer type, find the correct
40 /// null to store into it.
41 static llvm::Constant *getNullForVariable(Address addr) {
42   llvm::Type *type = addr.getElementType();
43   return llvm::ConstantPointerNull::get(cast<llvm::PointerType>(type));
44 }
45 
46 /// Emits an instance of NSConstantString representing the object.
47 llvm::Value *CodeGenFunction::EmitObjCStringLiteral(const ObjCStringLiteral *E)
48 {
49   llvm::Constant *C =
50       CGM.getObjCRuntime().GenerateConstantString(E->getString()).getPointer();
51   // FIXME: This bitcast should just be made an invariant on the Runtime.
52   return llvm::ConstantExpr::getBitCast(C, ConvertType(E->getType()));
53 }
54 
55 /// EmitObjCBoxedExpr - This routine generates code to call
56 /// the appropriate expression boxing method. This will either be
57 /// one of +[NSNumber numberWith<Type>:], or +[NSString stringWithUTF8String:],
58 /// or [NSValue valueWithBytes:objCType:].
59 ///
60 llvm::Value *
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   const Expr *SubExpr = E->getSubExpr();
66 
67   if (E->isExpressibleAsConstantInitializer()) {
68     ConstantEmitter ConstEmitter(CGM);
69     return ConstEmitter.tryEmitAbstract(E, E->getType());
70   }
71 
72   assert(BoxingMethod->isClassMethod() && "BoxingMethod must be a class method");
73   Selector Sel = BoxingMethod->getSelector();
74 
75   // Generate a reference to the class pointer, which will be the receiver.
76   // Assumes that the method was introduced in the class that should be
77   // messaged (avoids pulling it out of the result type).
78   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
79   const ObjCInterfaceDecl *ClassDecl = BoxingMethod->getClassInterface();
80   llvm::Value *Receiver = Runtime.GetClass(*this, ClassDecl);
81 
82   CallArgList Args;
83   const ParmVarDecl *ArgDecl = *BoxingMethod->param_begin();
84   QualType ArgQT = ArgDecl->getType().getUnqualifiedType();
85 
86   // ObjCBoxedExpr supports boxing of structs and unions
87   // via [NSValue valueWithBytes:objCType:]
88   const QualType ValueType(SubExpr->getType().getCanonicalType());
89   if (ValueType->isObjCBoxableRecordType()) {
90     // Emit CodeGen for first parameter
91     // and cast value to correct type
92     Address Temporary = CreateMemTemp(SubExpr->getType());
93     EmitAnyExprToMem(SubExpr, Temporary, Qualifiers(), /*isInit*/ true);
94     Address BitCast = Builder.CreateBitCast(Temporary, ConvertType(ArgQT));
95     Args.add(RValue::get(BitCast.getPointer()), ArgQT);
96 
97     // Create char array to store type encoding
98     std::string Str;
99     getContext().getObjCEncodingForType(ValueType, Str);
100     llvm::Constant *GV = CGM.GetAddrOfConstantCString(Str).getPointer();
101 
102     // Cast type encoding to correct type
103     const ParmVarDecl *EncodingDecl = BoxingMethod->parameters()[1];
104     QualType EncodingQT = EncodingDecl->getType().getUnqualifiedType();
105     llvm::Value *Cast = Builder.CreateBitCast(GV, ConvertType(EncodingQT));
106 
107     Args.add(RValue::get(Cast), EncodingQT);
108   } else {
109     Args.add(EmitAnyExpr(SubExpr), ArgQT);
110   }
111 
112   RValue result = Runtime.GenerateMessageSend(
113       *this, ReturnValueSlot(), BoxingMethod->getReturnType(), Sel, Receiver,
114       Args, ClassDecl, BoxingMethod);
115   return Builder.CreateBitCast(result.getScalarVal(),
116                                ConvertType(E->getType()));
117 }
118 
119 llvm::Value *CodeGenFunction::EmitObjCCollectionLiteral(const Expr *E,
120                                     const ObjCMethodDecl *MethodWithObjects) {
121   ASTContext &Context = CGM.getContext();
122   const ObjCDictionaryLiteral *DLE = nullptr;
123   const ObjCArrayLiteral *ALE = dyn_cast<ObjCArrayLiteral>(E);
124   if (!ALE)
125     DLE = cast<ObjCDictionaryLiteral>(E);
126 
127   // Optimize empty collections by referencing constants, when available.
128   uint64_t NumElements =
129     ALE ? ALE->getNumElements() : DLE->getNumElements();
130   if (NumElements == 0 && CGM.getLangOpts().ObjCRuntime.hasEmptyCollections()) {
131     StringRef ConstantName = ALE ? "__NSArray0__" : "__NSDictionary0__";
132     QualType IdTy(CGM.getContext().getObjCIdType());
133     llvm::Constant *Constant =
134         CGM.CreateRuntimeVariable(ConvertType(IdTy), ConstantName);
135     LValue LV = MakeNaturalAlignAddrLValue(Constant, IdTy);
136     llvm::Value *Ptr = EmitLoadOfScalar(LV, E->getBeginLoc());
137     cast<llvm::LoadInst>(Ptr)->setMetadata(
138         CGM.getModule().getMDKindID("invariant.load"),
139         llvm::MDNode::get(getLLVMContext(), None));
140     return Builder.CreateBitCast(Ptr, ConvertType(E->getType()));
141   }
142 
143   // Compute the type of the array we're initializing.
144   llvm::APInt APNumElements(Context.getTypeSize(Context.getSizeType()),
145                             NumElements);
146   QualType ElementType = Context.getObjCIdType().withConst();
147   QualType ElementArrayType
148     = Context.getConstantArrayType(ElementType, APNumElements, nullptr,
149                                    ArrayType::Normal, /*IndexTypeQuals=*/0);
150 
151   // Allocate the temporary array(s).
152   Address Objects = CreateMemTemp(ElementArrayType, "objects");
153   Address Keys = Address::invalid();
154   if (DLE)
155     Keys = CreateMemTemp(ElementArrayType, "keys");
156 
157   // In ARC, we may need to do extra work to keep all the keys and
158   // values alive until after the call.
159   SmallVector<llvm::Value *, 16> NeededObjects;
160   bool TrackNeededObjects =
161     (getLangOpts().ObjCAutoRefCount &&
162     CGM.getCodeGenOpts().OptimizationLevel != 0);
163 
164   // Perform the actual initialialization of the array(s).
165   for (uint64_t i = 0; i < NumElements; i++) {
166     if (ALE) {
167       // Emit the element and store it to the appropriate array slot.
168       const Expr *Rhs = ALE->getElement(i);
169       LValue LV = MakeAddrLValue(Builder.CreateConstArrayGEP(Objects, i),
170                                  ElementType, AlignmentSource::Decl);
171 
172       llvm::Value *value = EmitScalarExpr(Rhs);
173       EmitStoreThroughLValue(RValue::get(value), LV, true);
174       if (TrackNeededObjects) {
175         NeededObjects.push_back(value);
176       }
177     } else {
178       // Emit the key and store it to the appropriate array slot.
179       const Expr *Key = DLE->getKeyValueElement(i).Key;
180       LValue KeyLV = MakeAddrLValue(Builder.CreateConstArrayGEP(Keys, i),
181                                     ElementType, AlignmentSource::Decl);
182       llvm::Value *keyValue = EmitScalarExpr(Key);
183       EmitStoreThroughLValue(RValue::get(keyValue), KeyLV, /*isInit=*/true);
184 
185       // Emit the value and store it to the appropriate array slot.
186       const Expr *Value = DLE->getKeyValueElement(i).Value;
187       LValue ValueLV = MakeAddrLValue(Builder.CreateConstArrayGEP(Objects, i),
188                                       ElementType, AlignmentSource::Decl);
189       llvm::Value *valueValue = EmitScalarExpr(Value);
190       EmitStoreThroughLValue(RValue::get(valueValue), ValueLV, /*isInit=*/true);
191       if (TrackNeededObjects) {
192         NeededObjects.push_back(keyValue);
193         NeededObjects.push_back(valueValue);
194       }
195     }
196   }
197 
198   // Generate the argument list.
199   CallArgList Args;
200   ObjCMethodDecl::param_const_iterator PI = MethodWithObjects->param_begin();
201   const ParmVarDecl *argDecl = *PI++;
202   QualType ArgQT = argDecl->getType().getUnqualifiedType();
203   Args.add(RValue::get(Objects.getPointer()), ArgQT);
204   if (DLE) {
205     argDecl = *PI++;
206     ArgQT = argDecl->getType().getUnqualifiedType();
207     Args.add(RValue::get(Keys.getPointer()), ArgQT);
208   }
209   argDecl = *PI;
210   ArgQT = argDecl->getType().getUnqualifiedType();
211   llvm::Value *Count =
212     llvm::ConstantInt::get(CGM.getTypes().ConvertType(ArgQT), NumElements);
213   Args.add(RValue::get(Count), ArgQT);
214 
215   // Generate a reference to the class pointer, which will be the receiver.
216   Selector Sel = MethodWithObjects->getSelector();
217   QualType ResultType = E->getType();
218   const ObjCObjectPointerType *InterfacePointerType
219     = ResultType->getAsObjCInterfacePointerType();
220   ObjCInterfaceDecl *Class
221     = InterfacePointerType->getObjectType()->getInterface();
222   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
223   llvm::Value *Receiver = Runtime.GetClass(*this, Class);
224 
225   // Generate the message send.
226   RValue result = Runtime.GenerateMessageSend(
227       *this, ReturnValueSlot(), MethodWithObjects->getReturnType(), Sel,
228       Receiver, Args, Class, MethodWithObjects);
229 
230   // The above message send needs these objects, but in ARC they are
231   // passed in a buffer that is essentially __unsafe_unretained.
232   // Therefore we must prevent the optimizer from releasing them until
233   // after the call.
234   if (TrackNeededObjects) {
235     EmitARCIntrinsicUse(NeededObjects);
236   }
237 
238   return Builder.CreateBitCast(result.getScalarVal(),
239                                ConvertType(E->getType()));
240 }
241 
242 llvm::Value *CodeGenFunction::EmitObjCArrayLiteral(const ObjCArrayLiteral *E) {
243   return EmitObjCCollectionLiteral(E, E->getArrayWithObjectsMethod());
244 }
245 
246 llvm::Value *CodeGenFunction::EmitObjCDictionaryLiteral(
247                                             const ObjCDictionaryLiteral *E) {
248   return EmitObjCCollectionLiteral(E, E->getDictWithObjectsMethod());
249 }
250 
251 /// Emit a selector.
252 llvm::Value *CodeGenFunction::EmitObjCSelectorExpr(const ObjCSelectorExpr *E) {
253   // Untyped selector.
254   // Note that this implementation allows for non-constant strings to be passed
255   // as arguments to @selector().  Currently, the only thing preventing this
256   // behaviour is the type checking in the front end.
257   return CGM.getObjCRuntime().GetSelector(*this, E->getSelector());
258 }
259 
260 llvm::Value *CodeGenFunction::EmitObjCProtocolExpr(const ObjCProtocolExpr *E) {
261   // FIXME: This should pass the Decl not the name.
262   return CGM.getObjCRuntime().GenerateProtocolRef(*this, E->getProtocol());
263 }
264 
265 /// Adjust the type of an Objective-C object that doesn't match up due
266 /// to type erasure at various points, e.g., related result types or the use
267 /// of parameterized classes.
268 static RValue AdjustObjCObjectType(CodeGenFunction &CGF, QualType ExpT,
269                                    RValue Result) {
270   if (!ExpT->isObjCRetainableType())
271     return Result;
272 
273   // If the converted types are the same, we're done.
274   llvm::Type *ExpLLVMTy = CGF.ConvertType(ExpT);
275   if (ExpLLVMTy == Result.getScalarVal()->getType())
276     return Result;
277 
278   // We have applied a substitution. Cast the rvalue appropriately.
279   return RValue::get(CGF.Builder.CreateBitCast(Result.getScalarVal(),
280                                                ExpLLVMTy));
281 }
282 
283 /// Decide whether to extend the lifetime of the receiver of a
284 /// returns-inner-pointer message.
285 static bool
286 shouldExtendReceiverForInnerPointerMessage(const ObjCMessageExpr *message) {
287   switch (message->getReceiverKind()) {
288 
289   // For a normal instance message, we should extend unless the
290   // receiver is loaded from a variable with precise lifetime.
291   case ObjCMessageExpr::Instance: {
292     const Expr *receiver = message->getInstanceReceiver();
293 
294     // Look through OVEs.
295     if (auto opaque = dyn_cast<OpaqueValueExpr>(receiver)) {
296       if (opaque->getSourceExpr())
297         receiver = opaque->getSourceExpr()->IgnoreParens();
298     }
299 
300     const ImplicitCastExpr *ice = dyn_cast<ImplicitCastExpr>(receiver);
301     if (!ice || ice->getCastKind() != CK_LValueToRValue) return true;
302     receiver = ice->getSubExpr()->IgnoreParens();
303 
304     // Look through OVEs.
305     if (auto opaque = dyn_cast<OpaqueValueExpr>(receiver)) {
306       if (opaque->getSourceExpr())
307         receiver = opaque->getSourceExpr()->IgnoreParens();
308     }
309 
310     // Only __strong variables.
311     if (receiver->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
312       return true;
313 
314     // All ivars and fields have precise lifetime.
315     if (isa<MemberExpr>(receiver) || isa<ObjCIvarRefExpr>(receiver))
316       return false;
317 
318     // Otherwise, check for variables.
319     const DeclRefExpr *declRef = dyn_cast<DeclRefExpr>(ice->getSubExpr());
320     if (!declRef) return true;
321     const VarDecl *var = dyn_cast<VarDecl>(declRef->getDecl());
322     if (!var) return true;
323 
324     // All variables have precise lifetime except local variables with
325     // automatic storage duration that aren't specially marked.
326     return (var->hasLocalStorage() &&
327             !var->hasAttr<ObjCPreciseLifetimeAttr>());
328   }
329 
330   case ObjCMessageExpr::Class:
331   case ObjCMessageExpr::SuperClass:
332     // It's never necessary for class objects.
333     return false;
334 
335   case ObjCMessageExpr::SuperInstance:
336     // We generally assume that 'self' lives throughout a method call.
337     return false;
338   }
339 
340   llvm_unreachable("invalid receiver kind");
341 }
342 
343 /// Given an expression of ObjC pointer type, check whether it was
344 /// immediately loaded from an ARC __weak l-value.
345 static const Expr *findWeakLValue(const Expr *E) {
346   assert(E->getType()->isObjCRetainableType());
347   E = E->IgnoreParens();
348   if (auto CE = dyn_cast<CastExpr>(E)) {
349     if (CE->getCastKind() == CK_LValueToRValue) {
350       if (CE->getSubExpr()->getType().getObjCLifetime() == Qualifiers::OCL_Weak)
351         return CE->getSubExpr();
352     }
353   }
354 
355   return nullptr;
356 }
357 
358 /// The ObjC runtime may provide entrypoints that are likely to be faster
359 /// than an ordinary message send of the appropriate selector.
360 ///
361 /// The entrypoints are guaranteed to be equivalent to just sending the
362 /// corresponding message.  If the entrypoint is implemented naively as just a
363 /// message send, using it is a trade-off: it sacrifices a few cycles of
364 /// overhead to save a small amount of code.  However, it's possible for
365 /// runtimes to detect and special-case classes that use "standard"
366 /// behavior; if that's dynamically a large proportion of all objects, using
367 /// the entrypoint will also be faster than using a message send.
368 ///
369 /// If the runtime does support a required entrypoint, then this method will
370 /// generate a call and return the resulting value.  Otherwise it will return
371 /// None and the caller can generate a msgSend instead.
372 static Optional<llvm::Value *>
373 tryGenerateSpecializedMessageSend(CodeGenFunction &CGF, QualType ResultType,
374                                   llvm::Value *Receiver,
375                                   const CallArgList& Args, Selector Sel,
376                                   const ObjCMethodDecl *method,
377                                   bool isClassMessage) {
378   auto &CGM = CGF.CGM;
379   if (!CGM.getCodeGenOpts().ObjCConvertMessagesToRuntimeCalls)
380     return None;
381 
382   auto &Runtime = CGM.getLangOpts().ObjCRuntime;
383   switch (Sel.getMethodFamily()) {
384   case OMF_alloc:
385     if (isClassMessage &&
386         Runtime.shouldUseRuntimeFunctionsForAlloc() &&
387         ResultType->isObjCObjectPointerType()) {
388         // [Foo alloc] -> objc_alloc(Foo) or
389         // [self alloc] -> objc_alloc(self)
390         if (Sel.isUnarySelector() && Sel.getNameForSlot(0) == "alloc")
391           return CGF.EmitObjCAlloc(Receiver, CGF.ConvertType(ResultType));
392         // [Foo allocWithZone:nil] -> objc_allocWithZone(Foo) or
393         // [self allocWithZone:nil] -> objc_allocWithZone(self)
394         if (Sel.isKeywordSelector() && Sel.getNumArgs() == 1 &&
395             Args.size() == 1 && Args.front().getType()->isPointerType() &&
396             Sel.getNameForSlot(0) == "allocWithZone") {
397           const llvm::Value* arg = Args.front().getKnownRValue().getScalarVal();
398           if (isa<llvm::ConstantPointerNull>(arg))
399             return CGF.EmitObjCAllocWithZone(Receiver,
400                                              CGF.ConvertType(ResultType));
401           return None;
402         }
403     }
404     break;
405 
406   case OMF_autorelease:
407     if (ResultType->isObjCObjectPointerType() &&
408         CGM.getLangOpts().getGC() == LangOptions::NonGC &&
409         Runtime.shouldUseARCFunctionsForRetainRelease())
410       return CGF.EmitObjCAutorelease(Receiver, CGF.ConvertType(ResultType));
411     break;
412 
413   case OMF_retain:
414     if (ResultType->isObjCObjectPointerType() &&
415         CGM.getLangOpts().getGC() == LangOptions::NonGC &&
416         Runtime.shouldUseARCFunctionsForRetainRelease())
417       return CGF.EmitObjCRetainNonBlock(Receiver, CGF.ConvertType(ResultType));
418     break;
419 
420   case OMF_release:
421     if (ResultType->isVoidType() &&
422         CGM.getLangOpts().getGC() == LangOptions::NonGC &&
423         Runtime.shouldUseARCFunctionsForRetainRelease()) {
424       CGF.EmitObjCRelease(Receiver, ARCPreciseLifetime);
425       return nullptr;
426     }
427     break;
428 
429   default:
430     break;
431   }
432   return None;
433 }
434 
435 CodeGen::RValue CGObjCRuntime::GeneratePossiblySpecializedMessageSend(
436     CodeGenFunction &CGF, ReturnValueSlot Return, QualType ResultType,
437     Selector Sel, llvm::Value *Receiver, const CallArgList &Args,
438     const ObjCInterfaceDecl *OID, const ObjCMethodDecl *Method,
439     bool isClassMessage) {
440   if (Optional<llvm::Value *> SpecializedResult =
441           tryGenerateSpecializedMessageSend(CGF, ResultType, Receiver, Args,
442                                             Sel, Method, isClassMessage)) {
443     return RValue::get(SpecializedResult.getValue());
444   }
445   return GenerateMessageSend(CGF, Return, ResultType, Sel, Receiver, Args, OID,
446                              Method);
447 }
448 
449 static void AppendFirstImpliedRuntimeProtocols(
450     const ObjCProtocolDecl *PD,
451     llvm::UniqueVector<const ObjCProtocolDecl *> &PDs) {
452   if (!PD->isNonRuntimeProtocol()) {
453     const auto *Can = PD->getCanonicalDecl();
454     PDs.insert(Can);
455     return;
456   }
457 
458   for (const auto *ParentPD : PD->protocols())
459     AppendFirstImpliedRuntimeProtocols(ParentPD, PDs);
460 }
461 
462 std::vector<const ObjCProtocolDecl *>
463 CGObjCRuntime::GetRuntimeProtocolList(ObjCProtocolDecl::protocol_iterator begin,
464                                       ObjCProtocolDecl::protocol_iterator end) {
465   std::vector<const ObjCProtocolDecl *> RuntimePds;
466   llvm::DenseSet<const ObjCProtocolDecl *> NonRuntimePDs;
467 
468   for (; begin != end; ++begin) {
469     const auto *It = *begin;
470     const auto *Can = It->getCanonicalDecl();
471     if (Can->isNonRuntimeProtocol())
472       NonRuntimePDs.insert(Can);
473     else
474       RuntimePds.push_back(Can);
475   }
476 
477   // If there are no non-runtime protocols then we can just stop now.
478   if (NonRuntimePDs.empty())
479     return RuntimePds;
480 
481   // Else we have to search through the non-runtime protocol's inheritancy
482   // hierarchy DAG stopping whenever a branch either finds a runtime protocol or
483   // a non-runtime protocol without any parents. These are the "first-implied"
484   // protocols from a non-runtime protocol.
485   llvm::UniqueVector<const ObjCProtocolDecl *> FirstImpliedProtos;
486   for (const auto *PD : NonRuntimePDs)
487     AppendFirstImpliedRuntimeProtocols(PD, FirstImpliedProtos);
488 
489   // Walk the Runtime list to get all protocols implied via the inclusion of
490   // this protocol, e.g. all protocols it inherits from including itself.
491   llvm::DenseSet<const ObjCProtocolDecl *> AllImpliedProtocols;
492   for (const auto *PD : RuntimePds) {
493     const auto *Can = PD->getCanonicalDecl();
494     AllImpliedProtocols.insert(Can);
495     Can->getImpliedProtocols(AllImpliedProtocols);
496   }
497 
498   // Similar to above, walk the list of first-implied protocols to find the set
499   // all the protocols implied excluding the listed protocols themselves since
500   // they are not yet a part of the `RuntimePds` list.
501   for (const auto *PD : FirstImpliedProtos) {
502     PD->getImpliedProtocols(AllImpliedProtocols);
503   }
504 
505   // From the first-implied list we have to finish building the final protocol
506   // list. If a protocol in the first-implied list was already implied via some
507   // inheritance path through some other protocols then it would be redundant to
508   // add it here and so we skip over it.
509   for (const auto *PD : FirstImpliedProtos) {
510     if (!AllImpliedProtocols.contains(PD)) {
511       RuntimePds.push_back(PD);
512     }
513   }
514 
515   return RuntimePds;
516 }
517 
518 /// Instead of '[[MyClass alloc] init]', try to generate
519 /// 'objc_alloc_init(MyClass)'. This provides a code size improvement on the
520 /// caller side, as well as the optimized objc_alloc.
521 static Optional<llvm::Value *>
522 tryEmitSpecializedAllocInit(CodeGenFunction &CGF, const ObjCMessageExpr *OME) {
523   auto &Runtime = CGF.getLangOpts().ObjCRuntime;
524   if (!Runtime.shouldUseRuntimeFunctionForCombinedAllocInit())
525     return None;
526 
527   // Match the exact pattern '[[MyClass alloc] init]'.
528   Selector Sel = OME->getSelector();
529   if (OME->getReceiverKind() != ObjCMessageExpr::Instance ||
530       !OME->getType()->isObjCObjectPointerType() || !Sel.isUnarySelector() ||
531       Sel.getNameForSlot(0) != "init")
532     return None;
533 
534   // Okay, this is '[receiver init]', check if 'receiver' is '[cls alloc]'
535   // with 'cls' a Class.
536   auto *SubOME =
537       dyn_cast<ObjCMessageExpr>(OME->getInstanceReceiver()->IgnoreParenCasts());
538   if (!SubOME)
539     return None;
540   Selector SubSel = SubOME->getSelector();
541 
542   if (!SubOME->getType()->isObjCObjectPointerType() ||
543       !SubSel.isUnarySelector() || SubSel.getNameForSlot(0) != "alloc")
544     return None;
545 
546   llvm::Value *Receiver = nullptr;
547   switch (SubOME->getReceiverKind()) {
548   case ObjCMessageExpr::Instance:
549     if (!SubOME->getInstanceReceiver()->getType()->isObjCClassType())
550       return None;
551     Receiver = CGF.EmitScalarExpr(SubOME->getInstanceReceiver());
552     break;
553 
554   case ObjCMessageExpr::Class: {
555     QualType ReceiverType = SubOME->getClassReceiver();
556     const ObjCObjectType *ObjTy = ReceiverType->castAs<ObjCObjectType>();
557     const ObjCInterfaceDecl *ID = ObjTy->getInterface();
558     assert(ID && "null interface should be impossible here");
559     Receiver = CGF.CGM.getObjCRuntime().GetClass(CGF, ID);
560     break;
561   }
562   case ObjCMessageExpr::SuperInstance:
563   case ObjCMessageExpr::SuperClass:
564     return None;
565   }
566 
567   return CGF.EmitObjCAllocInit(Receiver, CGF.ConvertType(OME->getType()));
568 }
569 
570 RValue CodeGenFunction::EmitObjCMessageExpr(const ObjCMessageExpr *E,
571                                             ReturnValueSlot Return) {
572   // Only the lookup mechanism and first two arguments of the method
573   // implementation vary between runtimes.  We can get the receiver and
574   // arguments in generic code.
575 
576   bool isDelegateInit = E->isDelegateInitCall();
577 
578   const ObjCMethodDecl *method = E->getMethodDecl();
579 
580   // If the method is -retain, and the receiver's being loaded from
581   // a __weak variable, peephole the entire operation to objc_loadWeakRetained.
582   if (method && E->getReceiverKind() == ObjCMessageExpr::Instance &&
583       method->getMethodFamily() == OMF_retain) {
584     if (auto lvalueExpr = findWeakLValue(E->getInstanceReceiver())) {
585       LValue lvalue = EmitLValue(lvalueExpr);
586       llvm::Value *result = EmitARCLoadWeakRetained(lvalue.getAddress(*this));
587       return AdjustObjCObjectType(*this, E->getType(), RValue::get(result));
588     }
589   }
590 
591   if (Optional<llvm::Value *> Val = tryEmitSpecializedAllocInit(*this, E))
592     return AdjustObjCObjectType(*this, E->getType(), RValue::get(*Val));
593 
594   // We don't retain the receiver in delegate init calls, and this is
595   // safe because the receiver value is always loaded from 'self',
596   // which we zero out.  We don't want to Block_copy block receivers,
597   // though.
598   bool retainSelf =
599     (!isDelegateInit &&
600      CGM.getLangOpts().ObjCAutoRefCount &&
601      method &&
602      method->hasAttr<NSConsumesSelfAttr>());
603 
604   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
605   bool isSuperMessage = false;
606   bool isClassMessage = false;
607   ObjCInterfaceDecl *OID = nullptr;
608   // Find the receiver
609   QualType ReceiverType;
610   llvm::Value *Receiver = nullptr;
611   switch (E->getReceiverKind()) {
612   case ObjCMessageExpr::Instance:
613     ReceiverType = E->getInstanceReceiver()->getType();
614     isClassMessage = ReceiverType->isObjCClassType();
615     if (retainSelf) {
616       TryEmitResult ter = tryEmitARCRetainScalarExpr(*this,
617                                                    E->getInstanceReceiver());
618       Receiver = ter.getPointer();
619       if (ter.getInt()) retainSelf = false;
620     } else
621       Receiver = EmitScalarExpr(E->getInstanceReceiver());
622     break;
623 
624   case ObjCMessageExpr::Class: {
625     ReceiverType = E->getClassReceiver();
626     OID = ReceiverType->castAs<ObjCObjectType>()->getInterface();
627     assert(OID && "Invalid Objective-C class message send");
628     Receiver = Runtime.GetClass(*this, OID);
629     isClassMessage = true;
630     break;
631   }
632 
633   case ObjCMessageExpr::SuperInstance:
634     ReceiverType = E->getSuperType();
635     Receiver = LoadObjCSelf();
636     isSuperMessage = true;
637     break;
638 
639   case ObjCMessageExpr::SuperClass:
640     ReceiverType = E->getSuperType();
641     Receiver = LoadObjCSelf();
642     isSuperMessage = true;
643     isClassMessage = true;
644     break;
645   }
646 
647   if (retainSelf)
648     Receiver = EmitARCRetainNonBlock(Receiver);
649 
650   // In ARC, we sometimes want to "extend the lifetime"
651   // (i.e. retain+autorelease) of receivers of returns-inner-pointer
652   // messages.
653   if (getLangOpts().ObjCAutoRefCount && method &&
654       method->hasAttr<ObjCReturnsInnerPointerAttr>() &&
655       shouldExtendReceiverForInnerPointerMessage(E))
656     Receiver = EmitARCRetainAutorelease(ReceiverType, Receiver);
657 
658   QualType ResultType = method ? method->getReturnType() : E->getType();
659 
660   CallArgList Args;
661   EmitCallArgs(Args, method, E->arguments(), /*AC*/AbstractCallee(method));
662 
663   // For delegate init calls in ARC, do an unsafe store of null into
664   // self.  This represents the call taking direct ownership of that
665   // value.  We have to do this after emitting the other call
666   // arguments because they might also reference self, but we don't
667   // have to worry about any of them modifying self because that would
668   // be an undefined read and write of an object in unordered
669   // expressions.
670   if (isDelegateInit) {
671     assert(getLangOpts().ObjCAutoRefCount &&
672            "delegate init calls should only be marked in ARC");
673 
674     // Do an unsafe store of null into self.
675     Address selfAddr =
676       GetAddrOfLocalVar(cast<ObjCMethodDecl>(CurCodeDecl)->getSelfDecl());
677     Builder.CreateStore(getNullForVariable(selfAddr), selfAddr);
678   }
679 
680   RValue result;
681   if (isSuperMessage) {
682     // super is only valid in an Objective-C method
683     const ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(CurFuncDecl);
684     bool isCategoryImpl = isa<ObjCCategoryImplDecl>(OMD->getDeclContext());
685     result = Runtime.GenerateMessageSendSuper(*this, Return, ResultType,
686                                               E->getSelector(),
687                                               OMD->getClassInterface(),
688                                               isCategoryImpl,
689                                               Receiver,
690                                               isClassMessage,
691                                               Args,
692                                               method);
693   } else {
694     // Call runtime methods directly if we can.
695     result = Runtime.GeneratePossiblySpecializedMessageSend(
696         *this, Return, ResultType, E->getSelector(), Receiver, Args, OID,
697         method, isClassMessage);
698   }
699 
700   // For delegate init calls in ARC, implicitly store the result of
701   // the call back into self.  This takes ownership of the value.
702   if (isDelegateInit) {
703     Address selfAddr =
704       GetAddrOfLocalVar(cast<ObjCMethodDecl>(CurCodeDecl)->getSelfDecl());
705     llvm::Value *newSelf = result.getScalarVal();
706 
707     // The delegate return type isn't necessarily a matching type; in
708     // fact, it's quite likely to be 'id'.
709     llvm::Type *selfTy = selfAddr.getElementType();
710     newSelf = Builder.CreateBitCast(newSelf, selfTy);
711 
712     Builder.CreateStore(newSelf, selfAddr);
713   }
714 
715   return AdjustObjCObjectType(*this, E->getType(), result);
716 }
717 
718 namespace {
719 struct FinishARCDealloc final : EHScopeStack::Cleanup {
720   void Emit(CodeGenFunction &CGF, Flags flags) override {
721     const ObjCMethodDecl *method = cast<ObjCMethodDecl>(CGF.CurCodeDecl);
722 
723     const ObjCImplDecl *impl = cast<ObjCImplDecl>(method->getDeclContext());
724     const ObjCInterfaceDecl *iface = impl->getClassInterface();
725     if (!iface->getSuperClass()) return;
726 
727     bool isCategory = isa<ObjCCategoryImplDecl>(impl);
728 
729     // Call [super dealloc] if we have a superclass.
730     llvm::Value *self = CGF.LoadObjCSelf();
731 
732     CallArgList args;
733     CGF.CGM.getObjCRuntime().GenerateMessageSendSuper(CGF, ReturnValueSlot(),
734                                                       CGF.getContext().VoidTy,
735                                                       method->getSelector(),
736                                                       iface,
737                                                       isCategory,
738                                                       self,
739                                                       /*is class msg*/ false,
740                                                       args,
741                                                       method);
742   }
743 };
744 }
745 
746 /// StartObjCMethod - Begin emission of an ObjCMethod. This generates
747 /// the LLVM function and sets the other context used by
748 /// CodeGenFunction.
749 void CodeGenFunction::StartObjCMethod(const ObjCMethodDecl *OMD,
750                                       const ObjCContainerDecl *CD) {
751   SourceLocation StartLoc = OMD->getBeginLoc();
752   FunctionArgList args;
753   // Check if we should generate debug info for this method.
754   if (OMD->hasAttr<NoDebugAttr>())
755     DebugInfo = nullptr; // disable debug info indefinitely for this function
756 
757   llvm::Function *Fn = CGM.getObjCRuntime().GenerateMethod(OMD, CD);
758 
759   const CGFunctionInfo &FI = CGM.getTypes().arrangeObjCMethodDeclaration(OMD);
760   if (OMD->isDirectMethod()) {
761     Fn->setVisibility(llvm::Function::HiddenVisibility);
762     CGM.SetLLVMFunctionAttributes(OMD, FI, Fn);
763     CGM.SetLLVMFunctionAttributesForDefinition(OMD, Fn);
764   } else {
765     CGM.SetInternalFunctionAttributes(OMD, Fn, FI);
766   }
767 
768   args.push_back(OMD->getSelfDecl());
769   args.push_back(OMD->getCmdDecl());
770 
771   args.append(OMD->param_begin(), OMD->param_end());
772 
773   CurGD = OMD;
774   CurEHLocation = OMD->getEndLoc();
775 
776   StartFunction(OMD, OMD->getReturnType(), Fn, FI, args,
777                 OMD->getLocation(), StartLoc);
778 
779   if (OMD->isDirectMethod()) {
780     // This function is a direct call, it has to implement a nil check
781     // on entry.
782     //
783     // TODO: possibly have several entry points to elide the check
784     CGM.getObjCRuntime().GenerateDirectMethodPrologue(*this, Fn, OMD, CD);
785   }
786 
787   // In ARC, certain methods get an extra cleanup.
788   if (CGM.getLangOpts().ObjCAutoRefCount &&
789       OMD->isInstanceMethod() &&
790       OMD->getSelector().isUnarySelector()) {
791     const IdentifierInfo *ident =
792       OMD->getSelector().getIdentifierInfoForSlot(0);
793     if (ident->isStr("dealloc"))
794       EHStack.pushCleanup<FinishARCDealloc>(getARCCleanupKind());
795   }
796 }
797 
798 static llvm::Value *emitARCRetainLoadOfScalar(CodeGenFunction &CGF,
799                                               LValue lvalue, QualType type);
800 
801 /// Generate an Objective-C method.  An Objective-C method is a C function with
802 /// its pointer, name, and types registered in the class structure.
803 void CodeGenFunction::GenerateObjCMethod(const ObjCMethodDecl *OMD) {
804   StartObjCMethod(OMD, OMD->getClassInterface());
805   PGO.assignRegionCounters(GlobalDecl(OMD), CurFn);
806   assert(isa<CompoundStmt>(OMD->getBody()));
807   incrementProfileCounter(OMD->getBody());
808   EmitCompoundStmtWithoutScope(*cast<CompoundStmt>(OMD->getBody()));
809   FinishFunction(OMD->getBodyRBrace());
810 }
811 
812 /// emitStructGetterCall - Call the runtime function to load a property
813 /// into the return value slot.
814 static void emitStructGetterCall(CodeGenFunction &CGF, ObjCIvarDecl *ivar,
815                                  bool isAtomic, bool hasStrong) {
816   ASTContext &Context = CGF.getContext();
817 
818   Address src =
819       CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), CGF.LoadObjCSelf(), ivar, 0)
820           .getAddress(CGF);
821 
822   // objc_copyStruct (ReturnValue, &structIvar,
823   //                  sizeof (Type of Ivar), isAtomic, false);
824   CallArgList args;
825 
826   Address dest = CGF.Builder.CreateBitCast(CGF.ReturnValue, CGF.VoidPtrTy);
827   args.add(RValue::get(dest.getPointer()), Context.VoidPtrTy);
828 
829   src = CGF.Builder.CreateBitCast(src, CGF.VoidPtrTy);
830   args.add(RValue::get(src.getPointer()), Context.VoidPtrTy);
831 
832   CharUnits size = CGF.getContext().getTypeSizeInChars(ivar->getType());
833   args.add(RValue::get(CGF.CGM.getSize(size)), Context.getSizeType());
834   args.add(RValue::get(CGF.Builder.getInt1(isAtomic)), Context.BoolTy);
835   args.add(RValue::get(CGF.Builder.getInt1(hasStrong)), Context.BoolTy);
836 
837   llvm::FunctionCallee fn = CGF.CGM.getObjCRuntime().GetGetStructFunction();
838   CGCallee callee = CGCallee::forDirect(fn);
839   CGF.EmitCall(CGF.getTypes().arrangeBuiltinFunctionCall(Context.VoidTy, args),
840                callee, ReturnValueSlot(), args);
841 }
842 
843 /// Determine whether the given architecture supports unaligned atomic
844 /// accesses.  They don't have to be fast, just faster than a function
845 /// call and a mutex.
846 static bool hasUnalignedAtomics(llvm::Triple::ArchType arch) {
847   // FIXME: Allow unaligned atomic load/store on x86.  (It is not
848   // currently supported by the backend.)
849   return 0;
850 }
851 
852 /// Return the maximum size that permits atomic accesses for the given
853 /// architecture.
854 static CharUnits getMaxAtomicAccessSize(CodeGenModule &CGM,
855                                         llvm::Triple::ArchType arch) {
856   // ARM has 8-byte atomic accesses, but it's not clear whether we
857   // want to rely on them here.
858 
859   // In the default case, just assume that any size up to a pointer is
860   // fine given adequate alignment.
861   return CharUnits::fromQuantity(CGM.PointerSizeInBytes);
862 }
863 
864 namespace {
865   class PropertyImplStrategy {
866   public:
867     enum StrategyKind {
868       /// The 'native' strategy is to use the architecture's provided
869       /// reads and writes.
870       Native,
871 
872       /// Use objc_setProperty and objc_getProperty.
873       GetSetProperty,
874 
875       /// Use objc_setProperty for the setter, but use expression
876       /// evaluation for the getter.
877       SetPropertyAndExpressionGet,
878 
879       /// Use objc_copyStruct.
880       CopyStruct,
881 
882       /// The 'expression' strategy is to emit normal assignment or
883       /// lvalue-to-rvalue expressions.
884       Expression
885     };
886 
887     StrategyKind getKind() const { return StrategyKind(Kind); }
888 
889     bool hasStrongMember() const { return HasStrong; }
890     bool isAtomic() const { return IsAtomic; }
891     bool isCopy() const { return IsCopy; }
892 
893     CharUnits getIvarSize() const { return IvarSize; }
894     CharUnits getIvarAlignment() const { return IvarAlignment; }
895 
896     PropertyImplStrategy(CodeGenModule &CGM,
897                          const ObjCPropertyImplDecl *propImpl);
898 
899   private:
900     unsigned Kind : 8;
901     unsigned IsAtomic : 1;
902     unsigned IsCopy : 1;
903     unsigned HasStrong : 1;
904 
905     CharUnits IvarSize;
906     CharUnits IvarAlignment;
907   };
908 }
909 
910 /// Pick an implementation strategy for the given property synthesis.
911 PropertyImplStrategy::PropertyImplStrategy(CodeGenModule &CGM,
912                                      const ObjCPropertyImplDecl *propImpl) {
913   const ObjCPropertyDecl *prop = propImpl->getPropertyDecl();
914   ObjCPropertyDecl::SetterKind setterKind = prop->getSetterKind();
915 
916   IsCopy = (setterKind == ObjCPropertyDecl::Copy);
917   IsAtomic = prop->isAtomic();
918   HasStrong = false; // doesn't matter here.
919 
920   // Evaluate the ivar's size and alignment.
921   ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
922   QualType ivarType = ivar->getType();
923   auto TInfo = CGM.getContext().getTypeInfoInChars(ivarType);
924   IvarSize = TInfo.Width;
925   IvarAlignment = TInfo.Align;
926 
927   // If we have a copy property, we always have to use getProperty/setProperty.
928   // TODO: we could actually use setProperty and an expression for non-atomics.
929   if (IsCopy) {
930     Kind = GetSetProperty;
931     return;
932   }
933 
934   // Handle retain.
935   if (setterKind == ObjCPropertyDecl::Retain) {
936     // In GC-only, there's nothing special that needs to be done.
937     if (CGM.getLangOpts().getGC() == LangOptions::GCOnly) {
938       // fallthrough
939 
940     // In ARC, if the property is non-atomic, use expression emission,
941     // which translates to objc_storeStrong.  This isn't required, but
942     // it's slightly nicer.
943     } else if (CGM.getLangOpts().ObjCAutoRefCount && !IsAtomic) {
944       // Using standard expression emission for the setter is only
945       // acceptable if the ivar is __strong, which won't be true if
946       // the property is annotated with __attribute__((NSObject)).
947       // TODO: falling all the way back to objc_setProperty here is
948       // just laziness, though;  we could still use objc_storeStrong
949       // if we hacked it right.
950       if (ivarType.getObjCLifetime() == Qualifiers::OCL_Strong)
951         Kind = Expression;
952       else
953         Kind = SetPropertyAndExpressionGet;
954       return;
955 
956     // Otherwise, we need to at least use setProperty.  However, if
957     // the property isn't atomic, we can use normal expression
958     // emission for the getter.
959     } else if (!IsAtomic) {
960       Kind = SetPropertyAndExpressionGet;
961       return;
962 
963     // Otherwise, we have to use both setProperty and getProperty.
964     } else {
965       Kind = GetSetProperty;
966       return;
967     }
968   }
969 
970   // If we're not atomic, just use expression accesses.
971   if (!IsAtomic) {
972     Kind = Expression;
973     return;
974   }
975 
976   // Properties on bitfield ivars need to be emitted using expression
977   // accesses even if they're nominally atomic.
978   if (ivar->isBitField()) {
979     Kind = Expression;
980     return;
981   }
982 
983   // GC-qualified or ARC-qualified ivars need to be emitted as
984   // expressions.  This actually works out to being atomic anyway,
985   // except for ARC __strong, but that should trigger the above code.
986   if (ivarType.hasNonTrivialObjCLifetime() ||
987       (CGM.getLangOpts().getGC() &&
988        CGM.getContext().getObjCGCAttrKind(ivarType))) {
989     Kind = Expression;
990     return;
991   }
992 
993   // Compute whether the ivar has strong members.
994   if (CGM.getLangOpts().getGC())
995     if (const RecordType *recordType = ivarType->getAs<RecordType>())
996       HasStrong = recordType->getDecl()->hasObjectMember();
997 
998   // We can never access structs with object members with a native
999   // access, because we need to use write barriers.  This is what
1000   // objc_copyStruct is for.
1001   if (HasStrong) {
1002     Kind = CopyStruct;
1003     return;
1004   }
1005 
1006   // Otherwise, this is target-dependent and based on the size and
1007   // alignment of the ivar.
1008 
1009   // If the size of the ivar is not a power of two, give up.  We don't
1010   // want to get into the business of doing compare-and-swaps.
1011   if (!IvarSize.isPowerOfTwo()) {
1012     Kind = CopyStruct;
1013     return;
1014   }
1015 
1016   llvm::Triple::ArchType arch =
1017     CGM.getTarget().getTriple().getArch();
1018 
1019   // Most architectures require memory to fit within a single cache
1020   // line, so the alignment has to be at least the size of the access.
1021   // Otherwise we have to grab a lock.
1022   if (IvarAlignment < IvarSize && !hasUnalignedAtomics(arch)) {
1023     Kind = CopyStruct;
1024     return;
1025   }
1026 
1027   // If the ivar's size exceeds the architecture's maximum atomic
1028   // access size, we have to use CopyStruct.
1029   if (IvarSize > getMaxAtomicAccessSize(CGM, arch)) {
1030     Kind = CopyStruct;
1031     return;
1032   }
1033 
1034   // Otherwise, we can use native loads and stores.
1035   Kind = Native;
1036 }
1037 
1038 /// Generate an Objective-C property getter function.
1039 ///
1040 /// The given Decl must be an ObjCImplementationDecl. \@synthesize
1041 /// is illegal within a category.
1042 void CodeGenFunction::GenerateObjCGetter(ObjCImplementationDecl *IMP,
1043                                          const ObjCPropertyImplDecl *PID) {
1044   llvm::Constant *AtomicHelperFn =
1045       CodeGenFunction(CGM).GenerateObjCAtomicGetterCopyHelperFunction(PID);
1046   ObjCMethodDecl *OMD = PID->getGetterMethodDecl();
1047   assert(OMD && "Invalid call to generate getter (empty method)");
1048   StartObjCMethod(OMD, IMP->getClassInterface());
1049 
1050   generateObjCGetterBody(IMP, PID, OMD, AtomicHelperFn);
1051 
1052   FinishFunction(OMD->getEndLoc());
1053 }
1054 
1055 static bool hasTrivialGetExpr(const ObjCPropertyImplDecl *propImpl) {
1056   const Expr *getter = propImpl->getGetterCXXConstructor();
1057   if (!getter) return true;
1058 
1059   // Sema only makes only of these when the ivar has a C++ class type,
1060   // so the form is pretty constrained.
1061 
1062   // If the property has a reference type, we might just be binding a
1063   // reference, in which case the result will be a gl-value.  We should
1064   // treat this as a non-trivial operation.
1065   if (getter->isGLValue())
1066     return false;
1067 
1068   // If we selected a trivial copy-constructor, we're okay.
1069   if (const CXXConstructExpr *construct = dyn_cast<CXXConstructExpr>(getter))
1070     return (construct->getConstructor()->isTrivial());
1071 
1072   // The constructor might require cleanups (in which case it's never
1073   // trivial).
1074   assert(isa<ExprWithCleanups>(getter));
1075   return false;
1076 }
1077 
1078 /// emitCPPObjectAtomicGetterCall - Call the runtime function to
1079 /// copy the ivar into the resturn slot.
1080 static void emitCPPObjectAtomicGetterCall(CodeGenFunction &CGF,
1081                                           llvm::Value *returnAddr,
1082                                           ObjCIvarDecl *ivar,
1083                                           llvm::Constant *AtomicHelperFn) {
1084   // objc_copyCppObjectAtomic (&returnSlot, &CppObjectIvar,
1085   //                           AtomicHelperFn);
1086   CallArgList args;
1087 
1088   // The 1st argument is the return Slot.
1089   args.add(RValue::get(returnAddr), CGF.getContext().VoidPtrTy);
1090 
1091   // The 2nd argument is the address of the ivar.
1092   llvm::Value *ivarAddr =
1093       CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), CGF.LoadObjCSelf(), ivar, 0)
1094           .getPointer(CGF);
1095   ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
1096   args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
1097 
1098   // Third argument is the helper function.
1099   args.add(RValue::get(AtomicHelperFn), CGF.getContext().VoidPtrTy);
1100 
1101   llvm::FunctionCallee copyCppAtomicObjectFn =
1102       CGF.CGM.getObjCRuntime().GetCppAtomicObjectGetFunction();
1103   CGCallee callee = CGCallee::forDirect(copyCppAtomicObjectFn);
1104   CGF.EmitCall(
1105       CGF.getTypes().arrangeBuiltinFunctionCall(CGF.getContext().VoidTy, args),
1106                callee, ReturnValueSlot(), args);
1107 }
1108 
1109 void
1110 CodeGenFunction::generateObjCGetterBody(const ObjCImplementationDecl *classImpl,
1111                                         const ObjCPropertyImplDecl *propImpl,
1112                                         const ObjCMethodDecl *GetterMethodDecl,
1113                                         llvm::Constant *AtomicHelperFn) {
1114   // If there's a non-trivial 'get' expression, we just have to emit that.
1115   if (!hasTrivialGetExpr(propImpl)) {
1116     if (!AtomicHelperFn) {
1117       auto *ret = ReturnStmt::Create(getContext(), SourceLocation(),
1118                                      propImpl->getGetterCXXConstructor(),
1119                                      /* NRVOCandidate=*/nullptr);
1120       EmitReturnStmt(*ret);
1121     }
1122     else {
1123       ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
1124       emitCPPObjectAtomicGetterCall(*this, ReturnValue.getPointer(),
1125                                     ivar, AtomicHelperFn);
1126     }
1127     return;
1128   }
1129 
1130   const ObjCPropertyDecl *prop = propImpl->getPropertyDecl();
1131   QualType propType = prop->getType();
1132   ObjCMethodDecl *getterMethod = propImpl->getGetterMethodDecl();
1133 
1134   ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
1135 
1136   // Pick an implementation strategy.
1137   PropertyImplStrategy strategy(CGM, propImpl);
1138   switch (strategy.getKind()) {
1139   case PropertyImplStrategy::Native: {
1140     // We don't need to do anything for a zero-size struct.
1141     if (strategy.getIvarSize().isZero())
1142       return;
1143 
1144     LValue LV = EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, 0);
1145 
1146     // Currently, all atomic accesses have to be through integer
1147     // types, so there's no point in trying to pick a prettier type.
1148     uint64_t ivarSize = getContext().toBits(strategy.getIvarSize());
1149     llvm::Type *bitcastType = llvm::Type::getIntNTy(getLLVMContext(), ivarSize);
1150     bitcastType = bitcastType->getPointerTo(); // addrspace 0 okay
1151 
1152     // Perform an atomic load.  This does not impose ordering constraints.
1153     Address ivarAddr = LV.getAddress(*this);
1154     ivarAddr = Builder.CreateBitCast(ivarAddr, bitcastType);
1155     llvm::LoadInst *load = Builder.CreateLoad(ivarAddr, "load");
1156     load->setAtomic(llvm::AtomicOrdering::Unordered);
1157 
1158     // Store that value into the return address.  Doing this with a
1159     // bitcast is likely to produce some pretty ugly IR, but it's not
1160     // the *most* terrible thing in the world.
1161     llvm::Type *retTy = ConvertType(getterMethod->getReturnType());
1162     uint64_t retTySize = CGM.getDataLayout().getTypeSizeInBits(retTy);
1163     llvm::Value *ivarVal = load;
1164     if (ivarSize > retTySize) {
1165       llvm::Type *newTy = llvm::Type::getIntNTy(getLLVMContext(), retTySize);
1166       ivarVal = Builder.CreateTrunc(load, newTy);
1167       bitcastType = newTy->getPointerTo();
1168     }
1169     Builder.CreateStore(ivarVal,
1170                         Builder.CreateBitCast(ReturnValue, bitcastType));
1171 
1172     // Make sure we don't do an autorelease.
1173     AutoreleaseResult = false;
1174     return;
1175   }
1176 
1177   case PropertyImplStrategy::GetSetProperty: {
1178     llvm::FunctionCallee getPropertyFn =
1179         CGM.getObjCRuntime().GetPropertyGetFunction();
1180     if (!getPropertyFn) {
1181       CGM.ErrorUnsupported(propImpl, "Obj-C getter requiring atomic copy");
1182       return;
1183     }
1184     CGCallee callee = CGCallee::forDirect(getPropertyFn);
1185 
1186     // Return (ivar-type) objc_getProperty((id) self, _cmd, offset, true).
1187     // FIXME: Can't this be simpler? This might even be worse than the
1188     // corresponding gcc code.
1189     llvm::Value *cmd =
1190       Builder.CreateLoad(GetAddrOfLocalVar(getterMethod->getCmdDecl()), "cmd");
1191     llvm::Value *self = Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
1192     llvm::Value *ivarOffset =
1193       EmitIvarOffset(classImpl->getClassInterface(), ivar);
1194 
1195     CallArgList args;
1196     args.add(RValue::get(self), getContext().getObjCIdType());
1197     args.add(RValue::get(cmd), getContext().getObjCSelType());
1198     args.add(RValue::get(ivarOffset), getContext().getPointerDiffType());
1199     args.add(RValue::get(Builder.getInt1(strategy.isAtomic())),
1200              getContext().BoolTy);
1201 
1202     // FIXME: We shouldn't need to get the function info here, the
1203     // runtime already should have computed it to build the function.
1204     llvm::CallBase *CallInstruction;
1205     RValue RV = EmitCall(getTypes().arrangeBuiltinFunctionCall(
1206                              getContext().getObjCIdType(), args),
1207                          callee, ReturnValueSlot(), args, &CallInstruction);
1208     if (llvm::CallInst *call = dyn_cast<llvm::CallInst>(CallInstruction))
1209       call->setTailCall();
1210 
1211     // We need to fix the type here. Ivars with copy & retain are
1212     // always objects so we don't need to worry about complex or
1213     // aggregates.
1214     RV = RValue::get(Builder.CreateBitCast(
1215         RV.getScalarVal(),
1216         getTypes().ConvertType(getterMethod->getReturnType())));
1217 
1218     EmitReturnOfRValue(RV, propType);
1219 
1220     // objc_getProperty does an autorelease, so we should suppress ours.
1221     AutoreleaseResult = false;
1222 
1223     return;
1224   }
1225 
1226   case PropertyImplStrategy::CopyStruct:
1227     emitStructGetterCall(*this, ivar, strategy.isAtomic(),
1228                          strategy.hasStrongMember());
1229     return;
1230 
1231   case PropertyImplStrategy::Expression:
1232   case PropertyImplStrategy::SetPropertyAndExpressionGet: {
1233     LValue LV = EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, 0);
1234 
1235     QualType ivarType = ivar->getType();
1236     switch (getEvaluationKind(ivarType)) {
1237     case TEK_Complex: {
1238       ComplexPairTy pair = EmitLoadOfComplex(LV, SourceLocation());
1239       EmitStoreOfComplex(pair, MakeAddrLValue(ReturnValue, ivarType),
1240                          /*init*/ true);
1241       return;
1242     }
1243     case TEK_Aggregate: {
1244       // The return value slot is guaranteed to not be aliased, but
1245       // that's not necessarily the same as "on the stack", so
1246       // we still potentially need objc_memmove_collectable.
1247       EmitAggregateCopy(/* Dest= */ MakeAddrLValue(ReturnValue, ivarType),
1248                         /* Src= */ LV, ivarType, getOverlapForReturnValue());
1249       return;
1250     }
1251     case TEK_Scalar: {
1252       llvm::Value *value;
1253       if (propType->isReferenceType()) {
1254         value = LV.getAddress(*this).getPointer();
1255       } else {
1256         // We want to load and autoreleaseReturnValue ARC __weak ivars.
1257         if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak) {
1258           if (getLangOpts().ObjCAutoRefCount) {
1259             value = emitARCRetainLoadOfScalar(*this, LV, ivarType);
1260           } else {
1261             value = EmitARCLoadWeak(LV.getAddress(*this));
1262           }
1263 
1264         // Otherwise we want to do a simple load, suppressing the
1265         // final autorelease.
1266         } else {
1267           value = EmitLoadOfLValue(LV, SourceLocation()).getScalarVal();
1268           AutoreleaseResult = false;
1269         }
1270 
1271         value = Builder.CreateBitCast(
1272             value, ConvertType(GetterMethodDecl->getReturnType()));
1273       }
1274 
1275       EmitReturnOfRValue(RValue::get(value), propType);
1276       return;
1277     }
1278     }
1279     llvm_unreachable("bad evaluation kind");
1280   }
1281 
1282   }
1283   llvm_unreachable("bad @property implementation strategy!");
1284 }
1285 
1286 /// emitStructSetterCall - Call the runtime function to store the value
1287 /// from the first formal parameter into the given ivar.
1288 static void emitStructSetterCall(CodeGenFunction &CGF, ObjCMethodDecl *OMD,
1289                                  ObjCIvarDecl *ivar) {
1290   // objc_copyStruct (&structIvar, &Arg,
1291   //                  sizeof (struct something), true, false);
1292   CallArgList args;
1293 
1294   // The first argument is the address of the ivar.
1295   llvm::Value *ivarAddr =
1296       CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), CGF.LoadObjCSelf(), ivar, 0)
1297           .getPointer(CGF);
1298   ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
1299   args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
1300 
1301   // The second argument is the address of the parameter variable.
1302   ParmVarDecl *argVar = *OMD->param_begin();
1303   DeclRefExpr argRef(CGF.getContext(), argVar, false,
1304                      argVar->getType().getNonReferenceType(), VK_LValue,
1305                      SourceLocation());
1306   llvm::Value *argAddr = CGF.EmitLValue(&argRef).getPointer(CGF);
1307   argAddr = CGF.Builder.CreateBitCast(argAddr, CGF.Int8PtrTy);
1308   args.add(RValue::get(argAddr), CGF.getContext().VoidPtrTy);
1309 
1310   // The third argument is the sizeof the type.
1311   llvm::Value *size =
1312     CGF.CGM.getSize(CGF.getContext().getTypeSizeInChars(ivar->getType()));
1313   args.add(RValue::get(size), CGF.getContext().getSizeType());
1314 
1315   // The fourth argument is the 'isAtomic' flag.
1316   args.add(RValue::get(CGF.Builder.getTrue()), CGF.getContext().BoolTy);
1317 
1318   // The fifth argument is the 'hasStrong' flag.
1319   // FIXME: should this really always be false?
1320   args.add(RValue::get(CGF.Builder.getFalse()), CGF.getContext().BoolTy);
1321 
1322   llvm::FunctionCallee fn = CGF.CGM.getObjCRuntime().GetSetStructFunction();
1323   CGCallee callee = CGCallee::forDirect(fn);
1324   CGF.EmitCall(
1325       CGF.getTypes().arrangeBuiltinFunctionCall(CGF.getContext().VoidTy, args),
1326                callee, ReturnValueSlot(), args);
1327 }
1328 
1329 /// emitCPPObjectAtomicSetterCall - Call the runtime function to store
1330 /// the value from the first formal parameter into the given ivar, using
1331 /// the Cpp API for atomic Cpp objects with non-trivial copy assignment.
1332 static void emitCPPObjectAtomicSetterCall(CodeGenFunction &CGF,
1333                                           ObjCMethodDecl *OMD,
1334                                           ObjCIvarDecl *ivar,
1335                                           llvm::Constant *AtomicHelperFn) {
1336   // objc_copyCppObjectAtomic (&CppObjectIvar, &Arg,
1337   //                           AtomicHelperFn);
1338   CallArgList args;
1339 
1340   // The first argument is the address of the ivar.
1341   llvm::Value *ivarAddr =
1342       CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), CGF.LoadObjCSelf(), ivar, 0)
1343           .getPointer(CGF);
1344   ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
1345   args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
1346 
1347   // The second argument is the address of the parameter variable.
1348   ParmVarDecl *argVar = *OMD->param_begin();
1349   DeclRefExpr argRef(CGF.getContext(), argVar, false,
1350                      argVar->getType().getNonReferenceType(), VK_LValue,
1351                      SourceLocation());
1352   llvm::Value *argAddr = CGF.EmitLValue(&argRef).getPointer(CGF);
1353   argAddr = CGF.Builder.CreateBitCast(argAddr, CGF.Int8PtrTy);
1354   args.add(RValue::get(argAddr), CGF.getContext().VoidPtrTy);
1355 
1356   // Third argument is the helper function.
1357   args.add(RValue::get(AtomicHelperFn), CGF.getContext().VoidPtrTy);
1358 
1359   llvm::FunctionCallee fn =
1360       CGF.CGM.getObjCRuntime().GetCppAtomicObjectSetFunction();
1361   CGCallee callee = CGCallee::forDirect(fn);
1362   CGF.EmitCall(
1363       CGF.getTypes().arrangeBuiltinFunctionCall(CGF.getContext().VoidTy, args),
1364                callee, ReturnValueSlot(), args);
1365 }
1366 
1367 
1368 static bool hasTrivialSetExpr(const ObjCPropertyImplDecl *PID) {
1369   Expr *setter = PID->getSetterCXXAssignment();
1370   if (!setter) return true;
1371 
1372   // Sema only makes only of these when the ivar has a C++ class type,
1373   // so the form is pretty constrained.
1374 
1375   // An operator call is trivial if the function it calls is trivial.
1376   // This also implies that there's nothing non-trivial going on with
1377   // the arguments, because operator= can only be trivial if it's a
1378   // synthesized assignment operator and therefore both parameters are
1379   // references.
1380   if (CallExpr *call = dyn_cast<CallExpr>(setter)) {
1381     if (const FunctionDecl *callee
1382           = dyn_cast_or_null<FunctionDecl>(call->getCalleeDecl()))
1383       if (callee->isTrivial())
1384         return true;
1385     return false;
1386   }
1387 
1388   assert(isa<ExprWithCleanups>(setter));
1389   return false;
1390 }
1391 
1392 static bool UseOptimizedSetter(CodeGenModule &CGM) {
1393   if (CGM.getLangOpts().getGC() != LangOptions::NonGC)
1394     return false;
1395   return CGM.getLangOpts().ObjCRuntime.hasOptimizedSetter();
1396 }
1397 
1398 void
1399 CodeGenFunction::generateObjCSetterBody(const ObjCImplementationDecl *classImpl,
1400                                         const ObjCPropertyImplDecl *propImpl,
1401                                         llvm::Constant *AtomicHelperFn) {
1402   ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
1403   ObjCMethodDecl *setterMethod = propImpl->getSetterMethodDecl();
1404 
1405   // Just use the setter expression if Sema gave us one and it's
1406   // non-trivial.
1407   if (!hasTrivialSetExpr(propImpl)) {
1408     if (!AtomicHelperFn)
1409       // If non-atomic, assignment is called directly.
1410       EmitStmt(propImpl->getSetterCXXAssignment());
1411     else
1412       // If atomic, assignment is called via a locking api.
1413       emitCPPObjectAtomicSetterCall(*this, setterMethod, ivar,
1414                                     AtomicHelperFn);
1415     return;
1416   }
1417 
1418   PropertyImplStrategy strategy(CGM, propImpl);
1419   switch (strategy.getKind()) {
1420   case PropertyImplStrategy::Native: {
1421     // We don't need to do anything for a zero-size struct.
1422     if (strategy.getIvarSize().isZero())
1423       return;
1424 
1425     Address argAddr = GetAddrOfLocalVar(*setterMethod->param_begin());
1426 
1427     LValue ivarLValue =
1428       EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, /*quals*/ 0);
1429     Address ivarAddr = ivarLValue.getAddress(*this);
1430 
1431     // Currently, all atomic accesses have to be through integer
1432     // types, so there's no point in trying to pick a prettier type.
1433     llvm::Type *bitcastType =
1434       llvm::Type::getIntNTy(getLLVMContext(),
1435                             getContext().toBits(strategy.getIvarSize()));
1436 
1437     // Cast both arguments to the chosen operation type.
1438     argAddr = Builder.CreateElementBitCast(argAddr, bitcastType);
1439     ivarAddr = Builder.CreateElementBitCast(ivarAddr, bitcastType);
1440 
1441     // This bitcast load is likely to cause some nasty IR.
1442     llvm::Value *load = Builder.CreateLoad(argAddr);
1443 
1444     // Perform an atomic store.  There are no memory ordering requirements.
1445     llvm::StoreInst *store = Builder.CreateStore(load, ivarAddr);
1446     store->setAtomic(llvm::AtomicOrdering::Unordered);
1447     return;
1448   }
1449 
1450   case PropertyImplStrategy::GetSetProperty:
1451   case PropertyImplStrategy::SetPropertyAndExpressionGet: {
1452 
1453     llvm::FunctionCallee setOptimizedPropertyFn = nullptr;
1454     llvm::FunctionCallee setPropertyFn = nullptr;
1455     if (UseOptimizedSetter(CGM)) {
1456       // 10.8 and iOS 6.0 code and GC is off
1457       setOptimizedPropertyFn =
1458           CGM.getObjCRuntime().GetOptimizedPropertySetFunction(
1459               strategy.isAtomic(), strategy.isCopy());
1460       if (!setOptimizedPropertyFn) {
1461         CGM.ErrorUnsupported(propImpl, "Obj-C optimized setter - NYI");
1462         return;
1463       }
1464     }
1465     else {
1466       setPropertyFn = CGM.getObjCRuntime().GetPropertySetFunction();
1467       if (!setPropertyFn) {
1468         CGM.ErrorUnsupported(propImpl, "Obj-C setter requiring atomic copy");
1469         return;
1470       }
1471     }
1472 
1473     // Emit objc_setProperty((id) self, _cmd, offset, arg,
1474     //                       <is-atomic>, <is-copy>).
1475     llvm::Value *cmd =
1476       Builder.CreateLoad(GetAddrOfLocalVar(setterMethod->getCmdDecl()));
1477     llvm::Value *self =
1478       Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
1479     llvm::Value *ivarOffset =
1480       EmitIvarOffset(classImpl->getClassInterface(), ivar);
1481     Address argAddr = GetAddrOfLocalVar(*setterMethod->param_begin());
1482     llvm::Value *arg = Builder.CreateLoad(argAddr, "arg");
1483     arg = Builder.CreateBitCast(arg, VoidPtrTy);
1484 
1485     CallArgList args;
1486     args.add(RValue::get(self), getContext().getObjCIdType());
1487     args.add(RValue::get(cmd), getContext().getObjCSelType());
1488     if (setOptimizedPropertyFn) {
1489       args.add(RValue::get(arg), getContext().getObjCIdType());
1490       args.add(RValue::get(ivarOffset), getContext().getPointerDiffType());
1491       CGCallee callee = CGCallee::forDirect(setOptimizedPropertyFn);
1492       EmitCall(getTypes().arrangeBuiltinFunctionCall(getContext().VoidTy, args),
1493                callee, ReturnValueSlot(), args);
1494     } else {
1495       args.add(RValue::get(ivarOffset), getContext().getPointerDiffType());
1496       args.add(RValue::get(arg), getContext().getObjCIdType());
1497       args.add(RValue::get(Builder.getInt1(strategy.isAtomic())),
1498                getContext().BoolTy);
1499       args.add(RValue::get(Builder.getInt1(strategy.isCopy())),
1500                getContext().BoolTy);
1501       // FIXME: We shouldn't need to get the function info here, the runtime
1502       // already should have computed it to build the function.
1503       CGCallee callee = CGCallee::forDirect(setPropertyFn);
1504       EmitCall(getTypes().arrangeBuiltinFunctionCall(getContext().VoidTy, args),
1505                callee, ReturnValueSlot(), args);
1506     }
1507 
1508     return;
1509   }
1510 
1511   case PropertyImplStrategy::CopyStruct:
1512     emitStructSetterCall(*this, setterMethod, ivar);
1513     return;
1514 
1515   case PropertyImplStrategy::Expression:
1516     break;
1517   }
1518 
1519   // Otherwise, fake up some ASTs and emit a normal assignment.
1520   ValueDecl *selfDecl = setterMethod->getSelfDecl();
1521   DeclRefExpr self(getContext(), selfDecl, false, selfDecl->getType(),
1522                    VK_LValue, SourceLocation());
1523   ImplicitCastExpr selfLoad(ImplicitCastExpr::OnStack, selfDecl->getType(),
1524                             CK_LValueToRValue, &self, VK_RValue,
1525                             FPOptionsOverride());
1526   ObjCIvarRefExpr ivarRef(ivar, ivar->getType().getNonReferenceType(),
1527                           SourceLocation(), SourceLocation(),
1528                           &selfLoad, true, true);
1529 
1530   ParmVarDecl *argDecl = *setterMethod->param_begin();
1531   QualType argType = argDecl->getType().getNonReferenceType();
1532   DeclRefExpr arg(getContext(), argDecl, false, argType, VK_LValue,
1533                   SourceLocation());
1534   ImplicitCastExpr argLoad(ImplicitCastExpr::OnStack,
1535                            argType.getUnqualifiedType(), CK_LValueToRValue,
1536                            &arg, VK_RValue, FPOptionsOverride());
1537 
1538   // The property type can differ from the ivar type in some situations with
1539   // Objective-C pointer types, we can always bit cast the RHS in these cases.
1540   // The following absurdity is just to ensure well-formed IR.
1541   CastKind argCK = CK_NoOp;
1542   if (ivarRef.getType()->isObjCObjectPointerType()) {
1543     if (argLoad.getType()->isObjCObjectPointerType())
1544       argCK = CK_BitCast;
1545     else if (argLoad.getType()->isBlockPointerType())
1546       argCK = CK_BlockPointerToObjCPointerCast;
1547     else
1548       argCK = CK_CPointerToObjCPointerCast;
1549   } else if (ivarRef.getType()->isBlockPointerType()) {
1550      if (argLoad.getType()->isBlockPointerType())
1551       argCK = CK_BitCast;
1552     else
1553       argCK = CK_AnyPointerToBlockPointerCast;
1554   } else if (ivarRef.getType()->isPointerType()) {
1555     argCK = CK_BitCast;
1556   }
1557   ImplicitCastExpr argCast(ImplicitCastExpr::OnStack, ivarRef.getType(), argCK,
1558                            &argLoad, VK_RValue, FPOptionsOverride());
1559   Expr *finalArg = &argLoad;
1560   if (!getContext().hasSameUnqualifiedType(ivarRef.getType(),
1561                                            argLoad.getType()))
1562     finalArg = &argCast;
1563 
1564   BinaryOperator *assign = BinaryOperator::Create(
1565       getContext(), &ivarRef, finalArg, BO_Assign, ivarRef.getType(), VK_RValue,
1566       OK_Ordinary, SourceLocation(), FPOptionsOverride());
1567   EmitStmt(assign);
1568 }
1569 
1570 /// Generate an Objective-C property setter function.
1571 ///
1572 /// The given Decl must be an ObjCImplementationDecl. \@synthesize
1573 /// is illegal within a category.
1574 void CodeGenFunction::GenerateObjCSetter(ObjCImplementationDecl *IMP,
1575                                          const ObjCPropertyImplDecl *PID) {
1576   llvm::Constant *AtomicHelperFn =
1577       CodeGenFunction(CGM).GenerateObjCAtomicSetterCopyHelperFunction(PID);
1578   ObjCMethodDecl *OMD = PID->getSetterMethodDecl();
1579   assert(OMD && "Invalid call to generate setter (empty method)");
1580   StartObjCMethod(OMD, IMP->getClassInterface());
1581 
1582   generateObjCSetterBody(IMP, PID, AtomicHelperFn);
1583 
1584   FinishFunction(OMD->getEndLoc());
1585 }
1586 
1587 namespace {
1588   struct DestroyIvar final : EHScopeStack::Cleanup {
1589   private:
1590     llvm::Value *addr;
1591     const ObjCIvarDecl *ivar;
1592     CodeGenFunction::Destroyer *destroyer;
1593     bool useEHCleanupForArray;
1594   public:
1595     DestroyIvar(llvm::Value *addr, const ObjCIvarDecl *ivar,
1596                 CodeGenFunction::Destroyer *destroyer,
1597                 bool useEHCleanupForArray)
1598       : addr(addr), ivar(ivar), destroyer(destroyer),
1599         useEHCleanupForArray(useEHCleanupForArray) {}
1600 
1601     void Emit(CodeGenFunction &CGF, Flags flags) override {
1602       LValue lvalue
1603         = CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), addr, ivar, /*CVR*/ 0);
1604       CGF.emitDestroy(lvalue.getAddress(CGF), ivar->getType(), destroyer,
1605                       flags.isForNormalCleanup() && useEHCleanupForArray);
1606     }
1607   };
1608 }
1609 
1610 /// Like CodeGenFunction::destroyARCStrong, but do it with a call.
1611 static void destroyARCStrongWithStore(CodeGenFunction &CGF,
1612                                       Address addr,
1613                                       QualType type) {
1614   llvm::Value *null = getNullForVariable(addr);
1615   CGF.EmitARCStoreStrongCall(addr, null, /*ignored*/ true);
1616 }
1617 
1618 static void emitCXXDestructMethod(CodeGenFunction &CGF,
1619                                   ObjCImplementationDecl *impl) {
1620   CodeGenFunction::RunCleanupsScope scope(CGF);
1621 
1622   llvm::Value *self = CGF.LoadObjCSelf();
1623 
1624   const ObjCInterfaceDecl *iface = impl->getClassInterface();
1625   for (const ObjCIvarDecl *ivar = iface->all_declared_ivar_begin();
1626        ivar; ivar = ivar->getNextIvar()) {
1627     QualType type = ivar->getType();
1628 
1629     // Check whether the ivar is a destructible type.
1630     QualType::DestructionKind dtorKind = type.isDestructedType();
1631     if (!dtorKind) continue;
1632 
1633     CodeGenFunction::Destroyer *destroyer = nullptr;
1634 
1635     // Use a call to objc_storeStrong to destroy strong ivars, for the
1636     // general benefit of the tools.
1637     if (dtorKind == QualType::DK_objc_strong_lifetime) {
1638       destroyer = destroyARCStrongWithStore;
1639 
1640     // Otherwise use the default for the destruction kind.
1641     } else {
1642       destroyer = CGF.getDestroyer(dtorKind);
1643     }
1644 
1645     CleanupKind cleanupKind = CGF.getCleanupKind(dtorKind);
1646 
1647     CGF.EHStack.pushCleanup<DestroyIvar>(cleanupKind, self, ivar, destroyer,
1648                                          cleanupKind & EHCleanup);
1649   }
1650 
1651   assert(scope.requiresCleanups() && "nothing to do in .cxx_destruct?");
1652 }
1653 
1654 void CodeGenFunction::GenerateObjCCtorDtorMethod(ObjCImplementationDecl *IMP,
1655                                                  ObjCMethodDecl *MD,
1656                                                  bool ctor) {
1657   MD->createImplicitParams(CGM.getContext(), IMP->getClassInterface());
1658   StartObjCMethod(MD, IMP->getClassInterface());
1659 
1660   // Emit .cxx_construct.
1661   if (ctor) {
1662     // Suppress the final autorelease in ARC.
1663     AutoreleaseResult = false;
1664 
1665     for (const auto *IvarInit : IMP->inits()) {
1666       FieldDecl *Field = IvarInit->getAnyMember();
1667       ObjCIvarDecl *Ivar = cast<ObjCIvarDecl>(Field);
1668       LValue LV = EmitLValueForIvar(TypeOfSelfObject(),
1669                                     LoadObjCSelf(), Ivar, 0);
1670       EmitAggExpr(IvarInit->getInit(),
1671                   AggValueSlot::forLValue(LV, *this, AggValueSlot::IsDestructed,
1672                                           AggValueSlot::DoesNotNeedGCBarriers,
1673                                           AggValueSlot::IsNotAliased,
1674                                           AggValueSlot::DoesNotOverlap));
1675     }
1676     // constructor returns 'self'.
1677     CodeGenTypes &Types = CGM.getTypes();
1678     QualType IdTy(CGM.getContext().getObjCIdType());
1679     llvm::Value *SelfAsId =
1680       Builder.CreateBitCast(LoadObjCSelf(), Types.ConvertType(IdTy));
1681     EmitReturnOfRValue(RValue::get(SelfAsId), IdTy);
1682 
1683   // Emit .cxx_destruct.
1684   } else {
1685     emitCXXDestructMethod(*this, IMP);
1686   }
1687   FinishFunction();
1688 }
1689 
1690 llvm::Value *CodeGenFunction::LoadObjCSelf() {
1691   VarDecl *Self = cast<ObjCMethodDecl>(CurFuncDecl)->getSelfDecl();
1692   DeclRefExpr DRE(getContext(), Self,
1693                   /*is enclosing local*/ (CurFuncDecl != CurCodeDecl),
1694                   Self->getType(), VK_LValue, SourceLocation());
1695   return EmitLoadOfScalar(EmitDeclRefLValue(&DRE), SourceLocation());
1696 }
1697 
1698 QualType CodeGenFunction::TypeOfSelfObject() {
1699   const ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(CurFuncDecl);
1700   ImplicitParamDecl *selfDecl = OMD->getSelfDecl();
1701   const ObjCObjectPointerType *PTy = cast<ObjCObjectPointerType>(
1702     getContext().getCanonicalType(selfDecl->getType()));
1703   return PTy->getPointeeType();
1704 }
1705 
1706 void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
1707   llvm::FunctionCallee EnumerationMutationFnPtr =
1708       CGM.getObjCRuntime().EnumerationMutationFunction();
1709   if (!EnumerationMutationFnPtr) {
1710     CGM.ErrorUnsupported(&S, "Obj-C fast enumeration for this runtime");
1711     return;
1712   }
1713   CGCallee EnumerationMutationFn =
1714     CGCallee::forDirect(EnumerationMutationFnPtr);
1715 
1716   CGDebugInfo *DI = getDebugInfo();
1717   if (DI)
1718     DI->EmitLexicalBlockStart(Builder, S.getSourceRange().getBegin());
1719 
1720   RunCleanupsScope ForScope(*this);
1721 
1722   // The local variable comes into scope immediately.
1723   AutoVarEmission variable = AutoVarEmission::invalid();
1724   if (const DeclStmt *SD = dyn_cast<DeclStmt>(S.getElement()))
1725     variable = EmitAutoVarAlloca(*cast<VarDecl>(SD->getSingleDecl()));
1726 
1727   JumpDest LoopEnd = getJumpDestInCurrentScope("forcoll.end");
1728 
1729   // Fast enumeration state.
1730   QualType StateTy = CGM.getObjCFastEnumerationStateType();
1731   Address StatePtr = CreateMemTemp(StateTy, "state.ptr");
1732   EmitNullInitialization(StatePtr, StateTy);
1733 
1734   // Number of elements in the items array.
1735   static const unsigned NumItems = 16;
1736 
1737   // Fetch the countByEnumeratingWithState:objects:count: selector.
1738   IdentifierInfo *II[] = {
1739     &CGM.getContext().Idents.get("countByEnumeratingWithState"),
1740     &CGM.getContext().Idents.get("objects"),
1741     &CGM.getContext().Idents.get("count")
1742   };
1743   Selector FastEnumSel =
1744     CGM.getContext().Selectors.getSelector(llvm::array_lengthof(II), &II[0]);
1745 
1746   QualType ItemsTy =
1747     getContext().getConstantArrayType(getContext().getObjCIdType(),
1748                                       llvm::APInt(32, NumItems), nullptr,
1749                                       ArrayType::Normal, 0);
1750   Address ItemsPtr = CreateMemTemp(ItemsTy, "items.ptr");
1751 
1752   // Emit the collection pointer.  In ARC, we do a retain.
1753   llvm::Value *Collection;
1754   if (getLangOpts().ObjCAutoRefCount) {
1755     Collection = EmitARCRetainScalarExpr(S.getCollection());
1756 
1757     // Enter a cleanup to do the release.
1758     EmitObjCConsumeObject(S.getCollection()->getType(), Collection);
1759   } else {
1760     Collection = EmitScalarExpr(S.getCollection());
1761   }
1762 
1763   // The 'continue' label needs to appear within the cleanup for the
1764   // collection object.
1765   JumpDest AfterBody = getJumpDestInCurrentScope("forcoll.next");
1766 
1767   // Send it our message:
1768   CallArgList Args;
1769 
1770   // The first argument is a temporary of the enumeration-state type.
1771   Args.add(RValue::get(StatePtr.getPointer()),
1772            getContext().getPointerType(StateTy));
1773 
1774   // The second argument is a temporary array with space for NumItems
1775   // pointers.  We'll actually be loading elements from the array
1776   // pointer written into the control state; this buffer is so that
1777   // collections that *aren't* backed by arrays can still queue up
1778   // batches of elements.
1779   Args.add(RValue::get(ItemsPtr.getPointer()),
1780            getContext().getPointerType(ItemsTy));
1781 
1782   // The third argument is the capacity of that temporary array.
1783   llvm::Type *NSUIntegerTy = ConvertType(getContext().getNSUIntegerType());
1784   llvm::Constant *Count = llvm::ConstantInt::get(NSUIntegerTy, NumItems);
1785   Args.add(RValue::get(Count), getContext().getNSUIntegerType());
1786 
1787   // Start the enumeration.
1788   RValue CountRV =
1789       CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
1790                                                getContext().getNSUIntegerType(),
1791                                                FastEnumSel, Collection, Args);
1792 
1793   // The initial number of objects that were returned in the buffer.
1794   llvm::Value *initialBufferLimit = CountRV.getScalarVal();
1795 
1796   llvm::BasicBlock *EmptyBB = createBasicBlock("forcoll.empty");
1797   llvm::BasicBlock *LoopInitBB = createBasicBlock("forcoll.loopinit");
1798 
1799   llvm::Value *zero = llvm::Constant::getNullValue(NSUIntegerTy);
1800 
1801   // If the limit pointer was zero to begin with, the collection is
1802   // empty; skip all this. Set the branch weight assuming this has the same
1803   // probability of exiting the loop as any other loop exit.
1804   uint64_t EntryCount = getCurrentProfileCount();
1805   Builder.CreateCondBr(
1806       Builder.CreateICmpEQ(initialBufferLimit, zero, "iszero"), EmptyBB,
1807       LoopInitBB,
1808       createProfileWeights(EntryCount, getProfileCount(S.getBody())));
1809 
1810   // Otherwise, initialize the loop.
1811   EmitBlock(LoopInitBB);
1812 
1813   // Save the initial mutations value.  This is the value at an
1814   // address that was written into the state object by
1815   // countByEnumeratingWithState:objects:count:.
1816   Address StateMutationsPtrPtr =
1817       Builder.CreateStructGEP(StatePtr, 2, "mutationsptr.ptr");
1818   llvm::Value *StateMutationsPtr
1819     = Builder.CreateLoad(StateMutationsPtrPtr, "mutationsptr");
1820 
1821   llvm::Value *initialMutations =
1822     Builder.CreateAlignedLoad(StateMutationsPtr, getPointerAlign(),
1823                               "forcoll.initial-mutations");
1824 
1825   // Start looping.  This is the point we return to whenever we have a
1826   // fresh, non-empty batch of objects.
1827   llvm::BasicBlock *LoopBodyBB = createBasicBlock("forcoll.loopbody");
1828   EmitBlock(LoopBodyBB);
1829 
1830   // The current index into the buffer.
1831   llvm::PHINode *index = Builder.CreatePHI(NSUIntegerTy, 3, "forcoll.index");
1832   index->addIncoming(zero, LoopInitBB);
1833 
1834   // The current buffer size.
1835   llvm::PHINode *count = Builder.CreatePHI(NSUIntegerTy, 3, "forcoll.count");
1836   count->addIncoming(initialBufferLimit, LoopInitBB);
1837 
1838   incrementProfileCounter(&S);
1839 
1840   // Check whether the mutations value has changed from where it was
1841   // at start.  StateMutationsPtr should actually be invariant between
1842   // refreshes.
1843   StateMutationsPtr = Builder.CreateLoad(StateMutationsPtrPtr, "mutationsptr");
1844   llvm::Value *currentMutations
1845     = Builder.CreateAlignedLoad(StateMutationsPtr, getPointerAlign(),
1846                                 "statemutations");
1847 
1848   llvm::BasicBlock *WasMutatedBB = createBasicBlock("forcoll.mutated");
1849   llvm::BasicBlock *WasNotMutatedBB = createBasicBlock("forcoll.notmutated");
1850 
1851   Builder.CreateCondBr(Builder.CreateICmpEQ(currentMutations, initialMutations),
1852                        WasNotMutatedBB, WasMutatedBB);
1853 
1854   // If so, call the enumeration-mutation function.
1855   EmitBlock(WasMutatedBB);
1856   llvm::Value *V =
1857     Builder.CreateBitCast(Collection,
1858                           ConvertType(getContext().getObjCIdType()));
1859   CallArgList Args2;
1860   Args2.add(RValue::get(V), getContext().getObjCIdType());
1861   // FIXME: We shouldn't need to get the function info here, the runtime already
1862   // should have computed it to build the function.
1863   EmitCall(
1864           CGM.getTypes().arrangeBuiltinFunctionCall(getContext().VoidTy, Args2),
1865            EnumerationMutationFn, ReturnValueSlot(), Args2);
1866 
1867   // Otherwise, or if the mutation function returns, just continue.
1868   EmitBlock(WasNotMutatedBB);
1869 
1870   // Initialize the element variable.
1871   RunCleanupsScope elementVariableScope(*this);
1872   bool elementIsVariable;
1873   LValue elementLValue;
1874   QualType elementType;
1875   if (const DeclStmt *SD = dyn_cast<DeclStmt>(S.getElement())) {
1876     // Initialize the variable, in case it's a __block variable or something.
1877     EmitAutoVarInit(variable);
1878 
1879     const VarDecl *D = cast<VarDecl>(SD->getSingleDecl());
1880     DeclRefExpr tempDRE(getContext(), const_cast<VarDecl *>(D), false,
1881                         D->getType(), VK_LValue, SourceLocation());
1882     elementLValue = EmitLValue(&tempDRE);
1883     elementType = D->getType();
1884     elementIsVariable = true;
1885 
1886     if (D->isARCPseudoStrong())
1887       elementLValue.getQuals().setObjCLifetime(Qualifiers::OCL_ExplicitNone);
1888   } else {
1889     elementLValue = LValue(); // suppress warning
1890     elementType = cast<Expr>(S.getElement())->getType();
1891     elementIsVariable = false;
1892   }
1893   llvm::Type *convertedElementType = ConvertType(elementType);
1894 
1895   // Fetch the buffer out of the enumeration state.
1896   // TODO: this pointer should actually be invariant between
1897   // refreshes, which would help us do certain loop optimizations.
1898   Address StateItemsPtr =
1899       Builder.CreateStructGEP(StatePtr, 1, "stateitems.ptr");
1900   llvm::Value *EnumStateItems =
1901     Builder.CreateLoad(StateItemsPtr, "stateitems");
1902 
1903   // Fetch the value at the current index from the buffer.
1904   llvm::Value *CurrentItemPtr =
1905     Builder.CreateGEP(EnumStateItems, index, "currentitem.ptr");
1906   llvm::Value *CurrentItem =
1907     Builder.CreateAlignedLoad(CurrentItemPtr, getPointerAlign());
1908 
1909   if (SanOpts.has(SanitizerKind::ObjCCast)) {
1910     // Before using an item from the collection, check that the implicit cast
1911     // from id to the element type is valid. This is done with instrumentation
1912     // roughly corresponding to:
1913     //
1914     //   if (![item isKindOfClass:expectedCls]) { /* emit diagnostic */ }
1915     const ObjCObjectPointerType *ObjPtrTy =
1916         elementType->getAsObjCInterfacePointerType();
1917     const ObjCInterfaceType *InterfaceTy =
1918         ObjPtrTy ? ObjPtrTy->getInterfaceType() : nullptr;
1919     if (InterfaceTy) {
1920       SanitizerScope SanScope(this);
1921       auto &C = CGM.getContext();
1922       assert(InterfaceTy->getDecl() && "No decl for ObjC interface type");
1923       Selector IsKindOfClassSel = GetUnarySelector("isKindOfClass", C);
1924       CallArgList IsKindOfClassArgs;
1925       llvm::Value *Cls =
1926           CGM.getObjCRuntime().GetClass(*this, InterfaceTy->getDecl());
1927       IsKindOfClassArgs.add(RValue::get(Cls), C.getObjCClassType());
1928       llvm::Value *IsClass =
1929           CGM.getObjCRuntime()
1930               .GenerateMessageSend(*this, ReturnValueSlot(), C.BoolTy,
1931                                    IsKindOfClassSel, CurrentItem,
1932                                    IsKindOfClassArgs)
1933               .getScalarVal();
1934       llvm::Constant *StaticData[] = {
1935           EmitCheckSourceLocation(S.getBeginLoc()),
1936           EmitCheckTypeDescriptor(QualType(InterfaceTy, 0))};
1937       EmitCheck({{IsClass, SanitizerKind::ObjCCast}},
1938                 SanitizerHandler::InvalidObjCCast,
1939                 ArrayRef<llvm::Constant *>(StaticData), CurrentItem);
1940     }
1941   }
1942 
1943   // Cast that value to the right type.
1944   CurrentItem = Builder.CreateBitCast(CurrentItem, convertedElementType,
1945                                       "currentitem");
1946 
1947   // Make sure we have an l-value.  Yes, this gets evaluated every
1948   // time through the loop.
1949   if (!elementIsVariable) {
1950     elementLValue = EmitLValue(cast<Expr>(S.getElement()));
1951     EmitStoreThroughLValue(RValue::get(CurrentItem), elementLValue);
1952   } else {
1953     EmitStoreThroughLValue(RValue::get(CurrentItem), elementLValue,
1954                            /*isInit*/ true);
1955   }
1956 
1957   // If we do have an element variable, this assignment is the end of
1958   // its initialization.
1959   if (elementIsVariable)
1960     EmitAutoVarCleanups(variable);
1961 
1962   // Perform the loop body, setting up break and continue labels.
1963   BreakContinueStack.push_back(BreakContinue(LoopEnd, AfterBody));
1964   {
1965     RunCleanupsScope Scope(*this);
1966     EmitStmt(S.getBody());
1967   }
1968   BreakContinueStack.pop_back();
1969 
1970   // Destroy the element variable now.
1971   elementVariableScope.ForceCleanup();
1972 
1973   // Check whether there are more elements.
1974   EmitBlock(AfterBody.getBlock());
1975 
1976   llvm::BasicBlock *FetchMoreBB = createBasicBlock("forcoll.refetch");
1977 
1978   // First we check in the local buffer.
1979   llvm::Value *indexPlusOne =
1980       Builder.CreateAdd(index, llvm::ConstantInt::get(NSUIntegerTy, 1));
1981 
1982   // If we haven't overrun the buffer yet, we can continue.
1983   // Set the branch weights based on the simplifying assumption that this is
1984   // like a while-loop, i.e., ignoring that the false branch fetches more
1985   // elements and then returns to the loop.
1986   Builder.CreateCondBr(
1987       Builder.CreateICmpULT(indexPlusOne, count), LoopBodyBB, FetchMoreBB,
1988       createProfileWeights(getProfileCount(S.getBody()), EntryCount));
1989 
1990   index->addIncoming(indexPlusOne, AfterBody.getBlock());
1991   count->addIncoming(count, AfterBody.getBlock());
1992 
1993   // Otherwise, we have to fetch more elements.
1994   EmitBlock(FetchMoreBB);
1995 
1996   CountRV =
1997       CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
1998                                                getContext().getNSUIntegerType(),
1999                                                FastEnumSel, Collection, Args);
2000 
2001   // If we got a zero count, we're done.
2002   llvm::Value *refetchCount = CountRV.getScalarVal();
2003 
2004   // (note that the message send might split FetchMoreBB)
2005   index->addIncoming(zero, Builder.GetInsertBlock());
2006   count->addIncoming(refetchCount, Builder.GetInsertBlock());
2007 
2008   Builder.CreateCondBr(Builder.CreateICmpEQ(refetchCount, zero),
2009                        EmptyBB, LoopBodyBB);
2010 
2011   // No more elements.
2012   EmitBlock(EmptyBB);
2013 
2014   if (!elementIsVariable) {
2015     // If the element was not a declaration, set it to be null.
2016 
2017     llvm::Value *null = llvm::Constant::getNullValue(convertedElementType);
2018     elementLValue = EmitLValue(cast<Expr>(S.getElement()));
2019     EmitStoreThroughLValue(RValue::get(null), elementLValue);
2020   }
2021 
2022   if (DI)
2023     DI->EmitLexicalBlockEnd(Builder, S.getSourceRange().getEnd());
2024 
2025   ForScope.ForceCleanup();
2026   EmitBlock(LoopEnd.getBlock());
2027 }
2028 
2029 void CodeGenFunction::EmitObjCAtTryStmt(const ObjCAtTryStmt &S) {
2030   CGM.getObjCRuntime().EmitTryStmt(*this, S);
2031 }
2032 
2033 void CodeGenFunction::EmitObjCAtThrowStmt(const ObjCAtThrowStmt &S) {
2034   CGM.getObjCRuntime().EmitThrowStmt(*this, S);
2035 }
2036 
2037 void CodeGenFunction::EmitObjCAtSynchronizedStmt(
2038                                               const ObjCAtSynchronizedStmt &S) {
2039   CGM.getObjCRuntime().EmitSynchronizedStmt(*this, S);
2040 }
2041 
2042 namespace {
2043   struct CallObjCRelease final : EHScopeStack::Cleanup {
2044     CallObjCRelease(llvm::Value *object) : object(object) {}
2045     llvm::Value *object;
2046 
2047     void Emit(CodeGenFunction &CGF, Flags flags) override {
2048       // Releases at the end of the full-expression are imprecise.
2049       CGF.EmitARCRelease(object, ARCImpreciseLifetime);
2050     }
2051   };
2052 }
2053 
2054 /// Produce the code for a CK_ARCConsumeObject.  Does a primitive
2055 /// release at the end of the full-expression.
2056 llvm::Value *CodeGenFunction::EmitObjCConsumeObject(QualType type,
2057                                                     llvm::Value *object) {
2058   // If we're in a conditional branch, we need to make the cleanup
2059   // conditional.
2060   pushFullExprCleanup<CallObjCRelease>(getARCCleanupKind(), object);
2061   return object;
2062 }
2063 
2064 llvm::Value *CodeGenFunction::EmitObjCExtendObjectLifetime(QualType type,
2065                                                            llvm::Value *value) {
2066   return EmitARCRetainAutorelease(type, value);
2067 }
2068 
2069 /// Given a number of pointers, inform the optimizer that they're
2070 /// being intrinsically used up until this point in the program.
2071 void CodeGenFunction::EmitARCIntrinsicUse(ArrayRef<llvm::Value*> values) {
2072   llvm::Function *&fn = CGM.getObjCEntrypoints().clang_arc_use;
2073   if (!fn)
2074     fn = CGM.getIntrinsic(llvm::Intrinsic::objc_clang_arc_use);
2075 
2076   // This isn't really a "runtime" function, but as an intrinsic it
2077   // doesn't really matter as long as we align things up.
2078   EmitNounwindRuntimeCall(fn, values);
2079 }
2080 
2081 static void setARCRuntimeFunctionLinkage(CodeGenModule &CGM, llvm::Value *RTF) {
2082   if (auto *F = dyn_cast<llvm::Function>(RTF)) {
2083     // If the target runtime doesn't naturally support ARC, emit weak
2084     // references to the runtime support library.  We don't really
2085     // permit this to fail, but we need a particular relocation style.
2086     if (!CGM.getLangOpts().ObjCRuntime.hasNativeARC() &&
2087         !CGM.getTriple().isOSBinFormatCOFF()) {
2088       F->setLinkage(llvm::Function::ExternalWeakLinkage);
2089     }
2090   }
2091 }
2092 
2093 static void setARCRuntimeFunctionLinkage(CodeGenModule &CGM,
2094                                          llvm::FunctionCallee RTF) {
2095   setARCRuntimeFunctionLinkage(CGM, RTF.getCallee());
2096 }
2097 
2098 /// Perform an operation having the signature
2099 ///   i8* (i8*)
2100 /// where a null input causes a no-op and returns null.
2101 static llvm::Value *emitARCValueOperation(
2102     CodeGenFunction &CGF, llvm::Value *value, llvm::Type *returnType,
2103     llvm::Function *&fn, llvm::Intrinsic::ID IntID,
2104     llvm::CallInst::TailCallKind tailKind = llvm::CallInst::TCK_None) {
2105   if (isa<llvm::ConstantPointerNull>(value))
2106     return value;
2107 
2108   if (!fn) {
2109     fn = CGF.CGM.getIntrinsic(IntID);
2110     setARCRuntimeFunctionLinkage(CGF.CGM, fn);
2111   }
2112 
2113   // Cast the argument to 'id'.
2114   llvm::Type *origType = returnType ? returnType : value->getType();
2115   value = CGF.Builder.CreateBitCast(value, CGF.Int8PtrTy);
2116 
2117   // Call the function.
2118   llvm::CallInst *call = CGF.EmitNounwindRuntimeCall(fn, value);
2119   call->setTailCallKind(tailKind);
2120 
2121   // Cast the result back to the original type.
2122   return CGF.Builder.CreateBitCast(call, origType);
2123 }
2124 
2125 /// Perform an operation having the following signature:
2126 ///   i8* (i8**)
2127 static llvm::Value *emitARCLoadOperation(CodeGenFunction &CGF, Address addr,
2128                                          llvm::Function *&fn,
2129                                          llvm::Intrinsic::ID IntID) {
2130   if (!fn) {
2131     fn = CGF.CGM.getIntrinsic(IntID);
2132     setARCRuntimeFunctionLinkage(CGF.CGM, fn);
2133   }
2134 
2135   // Cast the argument to 'id*'.
2136   llvm::Type *origType = addr.getElementType();
2137   addr = CGF.Builder.CreateBitCast(addr, CGF.Int8PtrPtrTy);
2138 
2139   // Call the function.
2140   llvm::Value *result = CGF.EmitNounwindRuntimeCall(fn, addr.getPointer());
2141 
2142   // Cast the result back to a dereference of the original type.
2143   if (origType != CGF.Int8PtrTy)
2144     result = CGF.Builder.CreateBitCast(result, origType);
2145 
2146   return result;
2147 }
2148 
2149 /// Perform an operation having the following signature:
2150 ///   i8* (i8**, i8*)
2151 static llvm::Value *emitARCStoreOperation(CodeGenFunction &CGF, Address addr,
2152                                           llvm::Value *value,
2153                                           llvm::Function *&fn,
2154                                           llvm::Intrinsic::ID IntID,
2155                                           bool ignored) {
2156   assert(addr.getElementType() == value->getType());
2157 
2158   if (!fn) {
2159     fn = CGF.CGM.getIntrinsic(IntID);
2160     setARCRuntimeFunctionLinkage(CGF.CGM, fn);
2161   }
2162 
2163   llvm::Type *origType = value->getType();
2164 
2165   llvm::Value *args[] = {
2166     CGF.Builder.CreateBitCast(addr.getPointer(), CGF.Int8PtrPtrTy),
2167     CGF.Builder.CreateBitCast(value, CGF.Int8PtrTy)
2168   };
2169   llvm::CallInst *result = CGF.EmitNounwindRuntimeCall(fn, args);
2170 
2171   if (ignored) return nullptr;
2172 
2173   return CGF.Builder.CreateBitCast(result, origType);
2174 }
2175 
2176 /// Perform an operation having the following signature:
2177 ///   void (i8**, i8**)
2178 static void emitARCCopyOperation(CodeGenFunction &CGF, Address dst, Address src,
2179                                  llvm::Function *&fn,
2180                                  llvm::Intrinsic::ID IntID) {
2181   assert(dst.getType() == src.getType());
2182 
2183   if (!fn) {
2184     fn = CGF.CGM.getIntrinsic(IntID);
2185     setARCRuntimeFunctionLinkage(CGF.CGM, fn);
2186   }
2187 
2188   llvm::Value *args[] = {
2189     CGF.Builder.CreateBitCast(dst.getPointer(), CGF.Int8PtrPtrTy),
2190     CGF.Builder.CreateBitCast(src.getPointer(), CGF.Int8PtrPtrTy)
2191   };
2192   CGF.EmitNounwindRuntimeCall(fn, args);
2193 }
2194 
2195 /// Perform an operation having the signature
2196 ///   i8* (i8*)
2197 /// where a null input causes a no-op and returns null.
2198 static llvm::Value *emitObjCValueOperation(CodeGenFunction &CGF,
2199                                            llvm::Value *value,
2200                                            llvm::Type *returnType,
2201                                            llvm::FunctionCallee &fn,
2202                                            StringRef fnName) {
2203   if (isa<llvm::ConstantPointerNull>(value))
2204     return value;
2205 
2206   if (!fn) {
2207     llvm::FunctionType *fnType =
2208       llvm::FunctionType::get(CGF.Int8PtrTy, CGF.Int8PtrTy, false);
2209     fn = CGF.CGM.CreateRuntimeFunction(fnType, fnName);
2210 
2211     // We have Native ARC, so set nonlazybind attribute for performance
2212     if (llvm::Function *f = dyn_cast<llvm::Function>(fn.getCallee()))
2213       if (fnName == "objc_retain")
2214         f->addFnAttr(llvm::Attribute::NonLazyBind);
2215   }
2216 
2217   // Cast the argument to 'id'.
2218   llvm::Type *origType = returnType ? returnType : value->getType();
2219   value = CGF.Builder.CreateBitCast(value, CGF.Int8PtrTy);
2220 
2221   // Call the function.
2222   llvm::CallBase *Inst = CGF.EmitCallOrInvoke(fn, value);
2223 
2224   // Mark calls to objc_autorelease as tail on the assumption that methods
2225   // overriding autorelease do not touch anything on the stack.
2226   if (fnName == "objc_autorelease")
2227     if (auto *Call = dyn_cast<llvm::CallInst>(Inst))
2228       Call->setTailCall();
2229 
2230   // Cast the result back to the original type.
2231   return CGF.Builder.CreateBitCast(Inst, origType);
2232 }
2233 
2234 /// Produce the code to do a retain.  Based on the type, calls one of:
2235 ///   call i8* \@objc_retain(i8* %value)
2236 ///   call i8* \@objc_retainBlock(i8* %value)
2237 llvm::Value *CodeGenFunction::EmitARCRetain(QualType type, llvm::Value *value) {
2238   if (type->isBlockPointerType())
2239     return EmitARCRetainBlock(value, /*mandatory*/ false);
2240   else
2241     return EmitARCRetainNonBlock(value);
2242 }
2243 
2244 /// Retain the given object, with normal retain semantics.
2245 ///   call i8* \@objc_retain(i8* %value)
2246 llvm::Value *CodeGenFunction::EmitARCRetainNonBlock(llvm::Value *value) {
2247   return emitARCValueOperation(*this, value, nullptr,
2248                                CGM.getObjCEntrypoints().objc_retain,
2249                                llvm::Intrinsic::objc_retain);
2250 }
2251 
2252 /// Retain the given block, with _Block_copy semantics.
2253 ///   call i8* \@objc_retainBlock(i8* %value)
2254 ///
2255 /// \param mandatory - If false, emit the call with metadata
2256 /// indicating that it's okay for the optimizer to eliminate this call
2257 /// if it can prove that the block never escapes except down the stack.
2258 llvm::Value *CodeGenFunction::EmitARCRetainBlock(llvm::Value *value,
2259                                                  bool mandatory) {
2260   llvm::Value *result
2261     = emitARCValueOperation(*this, value, nullptr,
2262                             CGM.getObjCEntrypoints().objc_retainBlock,
2263                             llvm::Intrinsic::objc_retainBlock);
2264 
2265   // If the copy isn't mandatory, add !clang.arc.copy_on_escape to
2266   // tell the optimizer that it doesn't need to do this copy if the
2267   // block doesn't escape, where being passed as an argument doesn't
2268   // count as escaping.
2269   if (!mandatory && isa<llvm::Instruction>(result)) {
2270     llvm::CallInst *call
2271       = cast<llvm::CallInst>(result->stripPointerCasts());
2272     assert(call->getCalledOperand() ==
2273            CGM.getObjCEntrypoints().objc_retainBlock);
2274 
2275     call->setMetadata("clang.arc.copy_on_escape",
2276                       llvm::MDNode::get(Builder.getContext(), None));
2277   }
2278 
2279   return result;
2280 }
2281 
2282 static void emitAutoreleasedReturnValueMarker(CodeGenFunction &CGF) {
2283   // Fetch the void(void) inline asm which marks that we're going to
2284   // do something with the autoreleased return value.
2285   llvm::InlineAsm *&marker
2286     = CGF.CGM.getObjCEntrypoints().retainAutoreleasedReturnValueMarker;
2287   if (!marker) {
2288     StringRef assembly
2289       = CGF.CGM.getTargetCodeGenInfo()
2290            .getARCRetainAutoreleasedReturnValueMarker();
2291 
2292     // If we have an empty assembly string, there's nothing to do.
2293     if (assembly.empty()) {
2294 
2295     // Otherwise, at -O0, build an inline asm that we're going to call
2296     // in a moment.
2297     } else if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0) {
2298       llvm::FunctionType *type =
2299         llvm::FunctionType::get(CGF.VoidTy, /*variadic*/false);
2300 
2301       marker = llvm::InlineAsm::get(type, assembly, "", /*sideeffects*/ true);
2302 
2303     // If we're at -O1 and above, we don't want to litter the code
2304     // with this marker yet, so leave a breadcrumb for the ARC
2305     // optimizer to pick up.
2306     } else {
2307       const char *markerKey = "clang.arc.retainAutoreleasedReturnValueMarker";
2308       if (!CGF.CGM.getModule().getModuleFlag(markerKey)) {
2309         auto *str = llvm::MDString::get(CGF.getLLVMContext(), assembly);
2310         CGF.CGM.getModule().addModuleFlag(llvm::Module::Error, markerKey, str);
2311       }
2312     }
2313   }
2314 
2315   // Call the marker asm if we made one, which we do only at -O0.
2316   if (marker)
2317     CGF.Builder.CreateCall(marker, None, CGF.getBundlesForFunclet(marker));
2318 }
2319 
2320 /// Retain the given object which is the result of a function call.
2321 ///   call i8* \@objc_retainAutoreleasedReturnValue(i8* %value)
2322 ///
2323 /// Yes, this function name is one character away from a different
2324 /// call with completely different semantics.
2325 llvm::Value *
2326 CodeGenFunction::EmitARCRetainAutoreleasedReturnValue(llvm::Value *value) {
2327   emitAutoreleasedReturnValueMarker(*this);
2328   llvm::CallInst::TailCallKind tailKind =
2329       CGM.getTargetCodeGenInfo().markARCOptimizedReturnCallsAsNoTail()
2330           ? llvm::CallInst::TCK_NoTail
2331           : llvm::CallInst::TCK_None;
2332   return emitARCValueOperation(
2333       *this, value, nullptr,
2334       CGM.getObjCEntrypoints().objc_retainAutoreleasedReturnValue,
2335       llvm::Intrinsic::objc_retainAutoreleasedReturnValue, tailKind);
2336 }
2337 
2338 /// Claim a possibly-autoreleased return value at +0.  This is only
2339 /// valid to do in contexts which do not rely on the retain to keep
2340 /// the object valid for all of its uses; for example, when
2341 /// the value is ignored, or when it is being assigned to an
2342 /// __unsafe_unretained variable.
2343 ///
2344 ///   call i8* \@objc_unsafeClaimAutoreleasedReturnValue(i8* %value)
2345 llvm::Value *
2346 CodeGenFunction::EmitARCUnsafeClaimAutoreleasedReturnValue(llvm::Value *value) {
2347   emitAutoreleasedReturnValueMarker(*this);
2348   llvm::CallInst::TailCallKind tailKind =
2349       CGM.getTargetCodeGenInfo().markARCOptimizedReturnCallsAsNoTail()
2350           ? llvm::CallInst::TCK_NoTail
2351           : llvm::CallInst::TCK_None;
2352   return emitARCValueOperation(
2353       *this, value, nullptr,
2354       CGM.getObjCEntrypoints().objc_unsafeClaimAutoreleasedReturnValue,
2355       llvm::Intrinsic::objc_unsafeClaimAutoreleasedReturnValue, tailKind);
2356 }
2357 
2358 /// Release the given object.
2359 ///   call void \@objc_release(i8* %value)
2360 void CodeGenFunction::EmitARCRelease(llvm::Value *value,
2361                                      ARCPreciseLifetime_t precise) {
2362   if (isa<llvm::ConstantPointerNull>(value)) return;
2363 
2364   llvm::Function *&fn = CGM.getObjCEntrypoints().objc_release;
2365   if (!fn) {
2366     fn = CGM.getIntrinsic(llvm::Intrinsic::objc_release);
2367     setARCRuntimeFunctionLinkage(CGM, fn);
2368   }
2369 
2370   // Cast the argument to 'id'.
2371   value = Builder.CreateBitCast(value, Int8PtrTy);
2372 
2373   // Call objc_release.
2374   llvm::CallInst *call = EmitNounwindRuntimeCall(fn, value);
2375 
2376   if (precise == ARCImpreciseLifetime) {
2377     call->setMetadata("clang.imprecise_release",
2378                       llvm::MDNode::get(Builder.getContext(), None));
2379   }
2380 }
2381 
2382 /// Destroy a __strong variable.
2383 ///
2384 /// At -O0, emit a call to store 'null' into the address;
2385 /// instrumenting tools prefer this because the address is exposed,
2386 /// but it's relatively cumbersome to optimize.
2387 ///
2388 /// At -O1 and above, just load and call objc_release.
2389 ///
2390 ///   call void \@objc_storeStrong(i8** %addr, i8* null)
2391 void CodeGenFunction::EmitARCDestroyStrong(Address addr,
2392                                            ARCPreciseLifetime_t precise) {
2393   if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
2394     llvm::Value *null = getNullForVariable(addr);
2395     EmitARCStoreStrongCall(addr, null, /*ignored*/ true);
2396     return;
2397   }
2398 
2399   llvm::Value *value = Builder.CreateLoad(addr);
2400   EmitARCRelease(value, precise);
2401 }
2402 
2403 /// Store into a strong object.  Always calls this:
2404 ///   call void \@objc_storeStrong(i8** %addr, i8* %value)
2405 llvm::Value *CodeGenFunction::EmitARCStoreStrongCall(Address addr,
2406                                                      llvm::Value *value,
2407                                                      bool ignored) {
2408   assert(addr.getElementType() == value->getType());
2409 
2410   llvm::Function *&fn = CGM.getObjCEntrypoints().objc_storeStrong;
2411   if (!fn) {
2412     fn = CGM.getIntrinsic(llvm::Intrinsic::objc_storeStrong);
2413     setARCRuntimeFunctionLinkage(CGM, fn);
2414   }
2415 
2416   llvm::Value *args[] = {
2417     Builder.CreateBitCast(addr.getPointer(), Int8PtrPtrTy),
2418     Builder.CreateBitCast(value, Int8PtrTy)
2419   };
2420   EmitNounwindRuntimeCall(fn, args);
2421 
2422   if (ignored) return nullptr;
2423   return value;
2424 }
2425 
2426 /// Store into a strong object.  Sometimes calls this:
2427 ///   call void \@objc_storeStrong(i8** %addr, i8* %value)
2428 /// Other times, breaks it down into components.
2429 llvm::Value *CodeGenFunction::EmitARCStoreStrong(LValue dst,
2430                                                  llvm::Value *newValue,
2431                                                  bool ignored) {
2432   QualType type = dst.getType();
2433   bool isBlock = type->isBlockPointerType();
2434 
2435   // Use a store barrier at -O0 unless this is a block type or the
2436   // lvalue is inadequately aligned.
2437   if (shouldUseFusedARCCalls() &&
2438       !isBlock &&
2439       (dst.getAlignment().isZero() ||
2440        dst.getAlignment() >= CharUnits::fromQuantity(PointerAlignInBytes))) {
2441     return EmitARCStoreStrongCall(dst.getAddress(*this), newValue, ignored);
2442   }
2443 
2444   // Otherwise, split it out.
2445 
2446   // Retain the new value.
2447   newValue = EmitARCRetain(type, newValue);
2448 
2449   // Read the old value.
2450   llvm::Value *oldValue = EmitLoadOfScalar(dst, SourceLocation());
2451 
2452   // Store.  We do this before the release so that any deallocs won't
2453   // see the old value.
2454   EmitStoreOfScalar(newValue, dst);
2455 
2456   // Finally, release the old value.
2457   EmitARCRelease(oldValue, dst.isARCPreciseLifetime());
2458 
2459   return newValue;
2460 }
2461 
2462 /// Autorelease the given object.
2463 ///   call i8* \@objc_autorelease(i8* %value)
2464 llvm::Value *CodeGenFunction::EmitARCAutorelease(llvm::Value *value) {
2465   return emitARCValueOperation(*this, value, nullptr,
2466                                CGM.getObjCEntrypoints().objc_autorelease,
2467                                llvm::Intrinsic::objc_autorelease);
2468 }
2469 
2470 /// Autorelease the given object.
2471 ///   call i8* \@objc_autoreleaseReturnValue(i8* %value)
2472 llvm::Value *
2473 CodeGenFunction::EmitARCAutoreleaseReturnValue(llvm::Value *value) {
2474   return emitARCValueOperation(*this, value, nullptr,
2475                             CGM.getObjCEntrypoints().objc_autoreleaseReturnValue,
2476                                llvm::Intrinsic::objc_autoreleaseReturnValue,
2477                                llvm::CallInst::TCK_Tail);
2478 }
2479 
2480 /// Do a fused retain/autorelease of the given object.
2481 ///   call i8* \@objc_retainAutoreleaseReturnValue(i8* %value)
2482 llvm::Value *
2483 CodeGenFunction::EmitARCRetainAutoreleaseReturnValue(llvm::Value *value) {
2484   return emitARCValueOperation(*this, value, nullptr,
2485                      CGM.getObjCEntrypoints().objc_retainAutoreleaseReturnValue,
2486                              llvm::Intrinsic::objc_retainAutoreleaseReturnValue,
2487                                llvm::CallInst::TCK_Tail);
2488 }
2489 
2490 /// Do a fused retain/autorelease of the given object.
2491 ///   call i8* \@objc_retainAutorelease(i8* %value)
2492 /// or
2493 ///   %retain = call i8* \@objc_retainBlock(i8* %value)
2494 ///   call i8* \@objc_autorelease(i8* %retain)
2495 llvm::Value *CodeGenFunction::EmitARCRetainAutorelease(QualType type,
2496                                                        llvm::Value *value) {
2497   if (!type->isBlockPointerType())
2498     return EmitARCRetainAutoreleaseNonBlock(value);
2499 
2500   if (isa<llvm::ConstantPointerNull>(value)) return value;
2501 
2502   llvm::Type *origType = value->getType();
2503   value = Builder.CreateBitCast(value, Int8PtrTy);
2504   value = EmitARCRetainBlock(value, /*mandatory*/ true);
2505   value = EmitARCAutorelease(value);
2506   return Builder.CreateBitCast(value, origType);
2507 }
2508 
2509 /// Do a fused retain/autorelease of the given object.
2510 ///   call i8* \@objc_retainAutorelease(i8* %value)
2511 llvm::Value *
2512 CodeGenFunction::EmitARCRetainAutoreleaseNonBlock(llvm::Value *value) {
2513   return emitARCValueOperation(*this, value, nullptr,
2514                                CGM.getObjCEntrypoints().objc_retainAutorelease,
2515                                llvm::Intrinsic::objc_retainAutorelease);
2516 }
2517 
2518 /// i8* \@objc_loadWeak(i8** %addr)
2519 /// Essentially objc_autorelease(objc_loadWeakRetained(addr)).
2520 llvm::Value *CodeGenFunction::EmitARCLoadWeak(Address addr) {
2521   return emitARCLoadOperation(*this, addr,
2522                               CGM.getObjCEntrypoints().objc_loadWeak,
2523                               llvm::Intrinsic::objc_loadWeak);
2524 }
2525 
2526 /// i8* \@objc_loadWeakRetained(i8** %addr)
2527 llvm::Value *CodeGenFunction::EmitARCLoadWeakRetained(Address addr) {
2528   return emitARCLoadOperation(*this, addr,
2529                               CGM.getObjCEntrypoints().objc_loadWeakRetained,
2530                               llvm::Intrinsic::objc_loadWeakRetained);
2531 }
2532 
2533 /// i8* \@objc_storeWeak(i8** %addr, i8* %value)
2534 /// Returns %value.
2535 llvm::Value *CodeGenFunction::EmitARCStoreWeak(Address addr,
2536                                                llvm::Value *value,
2537                                                bool ignored) {
2538   return emitARCStoreOperation(*this, addr, value,
2539                                CGM.getObjCEntrypoints().objc_storeWeak,
2540                                llvm::Intrinsic::objc_storeWeak, ignored);
2541 }
2542 
2543 /// i8* \@objc_initWeak(i8** %addr, i8* %value)
2544 /// Returns %value.  %addr is known to not have a current weak entry.
2545 /// Essentially equivalent to:
2546 ///   *addr = nil; objc_storeWeak(addr, value);
2547 void CodeGenFunction::EmitARCInitWeak(Address addr, llvm::Value *value) {
2548   // If we're initializing to null, just write null to memory; no need
2549   // to get the runtime involved.  But don't do this if optimization
2550   // is enabled, because accounting for this would make the optimizer
2551   // much more complicated.
2552   if (isa<llvm::ConstantPointerNull>(value) &&
2553       CGM.getCodeGenOpts().OptimizationLevel == 0) {
2554     Builder.CreateStore(value, addr);
2555     return;
2556   }
2557 
2558   emitARCStoreOperation(*this, addr, value,
2559                         CGM.getObjCEntrypoints().objc_initWeak,
2560                         llvm::Intrinsic::objc_initWeak, /*ignored*/ true);
2561 }
2562 
2563 /// void \@objc_destroyWeak(i8** %addr)
2564 /// Essentially objc_storeWeak(addr, nil).
2565 void CodeGenFunction::EmitARCDestroyWeak(Address addr) {
2566   llvm::Function *&fn = CGM.getObjCEntrypoints().objc_destroyWeak;
2567   if (!fn) {
2568     fn = CGM.getIntrinsic(llvm::Intrinsic::objc_destroyWeak);
2569     setARCRuntimeFunctionLinkage(CGM, fn);
2570   }
2571 
2572   // Cast the argument to 'id*'.
2573   addr = Builder.CreateBitCast(addr, Int8PtrPtrTy);
2574 
2575   EmitNounwindRuntimeCall(fn, addr.getPointer());
2576 }
2577 
2578 /// void \@objc_moveWeak(i8** %dest, i8** %src)
2579 /// Disregards the current value in %dest.  Leaves %src pointing to nothing.
2580 /// Essentially (objc_copyWeak(dest, src), objc_destroyWeak(src)).
2581 void CodeGenFunction::EmitARCMoveWeak(Address dst, Address src) {
2582   emitARCCopyOperation(*this, dst, src,
2583                        CGM.getObjCEntrypoints().objc_moveWeak,
2584                        llvm::Intrinsic::objc_moveWeak);
2585 }
2586 
2587 /// void \@objc_copyWeak(i8** %dest, i8** %src)
2588 /// Disregards the current value in %dest.  Essentially
2589 ///   objc_release(objc_initWeak(dest, objc_readWeakRetained(src)))
2590 void CodeGenFunction::EmitARCCopyWeak(Address dst, Address src) {
2591   emitARCCopyOperation(*this, dst, src,
2592                        CGM.getObjCEntrypoints().objc_copyWeak,
2593                        llvm::Intrinsic::objc_copyWeak);
2594 }
2595 
2596 void CodeGenFunction::emitARCCopyAssignWeak(QualType Ty, Address DstAddr,
2597                                             Address SrcAddr) {
2598   llvm::Value *Object = EmitARCLoadWeakRetained(SrcAddr);
2599   Object = EmitObjCConsumeObject(Ty, Object);
2600   EmitARCStoreWeak(DstAddr, Object, false);
2601 }
2602 
2603 void CodeGenFunction::emitARCMoveAssignWeak(QualType Ty, Address DstAddr,
2604                                             Address SrcAddr) {
2605   llvm::Value *Object = EmitARCLoadWeakRetained(SrcAddr);
2606   Object = EmitObjCConsumeObject(Ty, Object);
2607   EmitARCStoreWeak(DstAddr, Object, false);
2608   EmitARCDestroyWeak(SrcAddr);
2609 }
2610 
2611 /// Produce the code to do a objc_autoreleasepool_push.
2612 ///   call i8* \@objc_autoreleasePoolPush(void)
2613 llvm::Value *CodeGenFunction::EmitObjCAutoreleasePoolPush() {
2614   llvm::Function *&fn = CGM.getObjCEntrypoints().objc_autoreleasePoolPush;
2615   if (!fn) {
2616     fn = CGM.getIntrinsic(llvm::Intrinsic::objc_autoreleasePoolPush);
2617     setARCRuntimeFunctionLinkage(CGM, fn);
2618   }
2619 
2620   return EmitNounwindRuntimeCall(fn);
2621 }
2622 
2623 /// Produce the code to do a primitive release.
2624 ///   call void \@objc_autoreleasePoolPop(i8* %ptr)
2625 void CodeGenFunction::EmitObjCAutoreleasePoolPop(llvm::Value *value) {
2626   assert(value->getType() == Int8PtrTy);
2627 
2628   if (getInvokeDest()) {
2629     // Call the runtime method not the intrinsic if we are handling exceptions
2630     llvm::FunctionCallee &fn =
2631         CGM.getObjCEntrypoints().objc_autoreleasePoolPopInvoke;
2632     if (!fn) {
2633       llvm::FunctionType *fnType =
2634         llvm::FunctionType::get(Builder.getVoidTy(), Int8PtrTy, false);
2635       fn = CGM.CreateRuntimeFunction(fnType, "objc_autoreleasePoolPop");
2636       setARCRuntimeFunctionLinkage(CGM, fn);
2637     }
2638 
2639     // objc_autoreleasePoolPop can throw.
2640     EmitRuntimeCallOrInvoke(fn, value);
2641   } else {
2642     llvm::FunctionCallee &fn = CGM.getObjCEntrypoints().objc_autoreleasePoolPop;
2643     if (!fn) {
2644       fn = CGM.getIntrinsic(llvm::Intrinsic::objc_autoreleasePoolPop);
2645       setARCRuntimeFunctionLinkage(CGM, fn);
2646     }
2647 
2648     EmitRuntimeCall(fn, value);
2649   }
2650 }
2651 
2652 /// Produce the code to do an MRR version objc_autoreleasepool_push.
2653 /// Which is: [[NSAutoreleasePool alloc] init];
2654 /// Where alloc is declared as: + (id) alloc; in NSAutoreleasePool class.
2655 /// init is declared as: - (id) init; in its NSObject super class.
2656 ///
2657 llvm::Value *CodeGenFunction::EmitObjCMRRAutoreleasePoolPush() {
2658   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
2659   llvm::Value *Receiver = Runtime.EmitNSAutoreleasePoolClassRef(*this);
2660   // [NSAutoreleasePool alloc]
2661   IdentifierInfo *II = &CGM.getContext().Idents.get("alloc");
2662   Selector AllocSel = getContext().Selectors.getSelector(0, &II);
2663   CallArgList Args;
2664   RValue AllocRV =
2665     Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
2666                                 getContext().getObjCIdType(),
2667                                 AllocSel, Receiver, Args);
2668 
2669   // [Receiver init]
2670   Receiver = AllocRV.getScalarVal();
2671   II = &CGM.getContext().Idents.get("init");
2672   Selector InitSel = getContext().Selectors.getSelector(0, &II);
2673   RValue InitRV =
2674     Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
2675                                 getContext().getObjCIdType(),
2676                                 InitSel, Receiver, Args);
2677   return InitRV.getScalarVal();
2678 }
2679 
2680 /// Allocate the given objc object.
2681 ///   call i8* \@objc_alloc(i8* %value)
2682 llvm::Value *CodeGenFunction::EmitObjCAlloc(llvm::Value *value,
2683                                             llvm::Type *resultType) {
2684   return emitObjCValueOperation(*this, value, resultType,
2685                                 CGM.getObjCEntrypoints().objc_alloc,
2686                                 "objc_alloc");
2687 }
2688 
2689 /// Allocate the given objc object.
2690 ///   call i8* \@objc_allocWithZone(i8* %value)
2691 llvm::Value *CodeGenFunction::EmitObjCAllocWithZone(llvm::Value *value,
2692                                                     llvm::Type *resultType) {
2693   return emitObjCValueOperation(*this, value, resultType,
2694                                 CGM.getObjCEntrypoints().objc_allocWithZone,
2695                                 "objc_allocWithZone");
2696 }
2697 
2698 llvm::Value *CodeGenFunction::EmitObjCAllocInit(llvm::Value *value,
2699                                                 llvm::Type *resultType) {
2700   return emitObjCValueOperation(*this, value, resultType,
2701                                 CGM.getObjCEntrypoints().objc_alloc_init,
2702                                 "objc_alloc_init");
2703 }
2704 
2705 /// Produce the code to do a primitive release.
2706 /// [tmp drain];
2707 void CodeGenFunction::EmitObjCMRRAutoreleasePoolPop(llvm::Value *Arg) {
2708   IdentifierInfo *II = &CGM.getContext().Idents.get("drain");
2709   Selector DrainSel = getContext().Selectors.getSelector(0, &II);
2710   CallArgList Args;
2711   CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
2712                               getContext().VoidTy, DrainSel, Arg, Args);
2713 }
2714 
2715 void CodeGenFunction::destroyARCStrongPrecise(CodeGenFunction &CGF,
2716                                               Address addr,
2717                                               QualType type) {
2718   CGF.EmitARCDestroyStrong(addr, ARCPreciseLifetime);
2719 }
2720 
2721 void CodeGenFunction::destroyARCStrongImprecise(CodeGenFunction &CGF,
2722                                                 Address addr,
2723                                                 QualType type) {
2724   CGF.EmitARCDestroyStrong(addr, ARCImpreciseLifetime);
2725 }
2726 
2727 void CodeGenFunction::destroyARCWeak(CodeGenFunction &CGF,
2728                                      Address addr,
2729                                      QualType type) {
2730   CGF.EmitARCDestroyWeak(addr);
2731 }
2732 
2733 void CodeGenFunction::emitARCIntrinsicUse(CodeGenFunction &CGF, Address addr,
2734                                           QualType type) {
2735   llvm::Value *value = CGF.Builder.CreateLoad(addr);
2736   CGF.EmitARCIntrinsicUse(value);
2737 }
2738 
2739 /// Autorelease the given object.
2740 ///   call i8* \@objc_autorelease(i8* %value)
2741 llvm::Value *CodeGenFunction::EmitObjCAutorelease(llvm::Value *value,
2742                                                   llvm::Type *returnType) {
2743   return emitObjCValueOperation(
2744       *this, value, returnType,
2745       CGM.getObjCEntrypoints().objc_autoreleaseRuntimeFunction,
2746       "objc_autorelease");
2747 }
2748 
2749 /// Retain the given object, with normal retain semantics.
2750 ///   call i8* \@objc_retain(i8* %value)
2751 llvm::Value *CodeGenFunction::EmitObjCRetainNonBlock(llvm::Value *value,
2752                                                      llvm::Type *returnType) {
2753   return emitObjCValueOperation(
2754       *this, value, returnType,
2755       CGM.getObjCEntrypoints().objc_retainRuntimeFunction, "objc_retain");
2756 }
2757 
2758 /// Release the given object.
2759 ///   call void \@objc_release(i8* %value)
2760 void CodeGenFunction::EmitObjCRelease(llvm::Value *value,
2761                                       ARCPreciseLifetime_t precise) {
2762   if (isa<llvm::ConstantPointerNull>(value)) return;
2763 
2764   llvm::FunctionCallee &fn =
2765       CGM.getObjCEntrypoints().objc_releaseRuntimeFunction;
2766   if (!fn) {
2767     llvm::FunctionType *fnType =
2768         llvm::FunctionType::get(Builder.getVoidTy(), Int8PtrTy, false);
2769     fn = CGM.CreateRuntimeFunction(fnType, "objc_release");
2770     setARCRuntimeFunctionLinkage(CGM, fn);
2771     // We have Native ARC, so set nonlazybind attribute for performance
2772     if (llvm::Function *f = dyn_cast<llvm::Function>(fn.getCallee()))
2773       f->addFnAttr(llvm::Attribute::NonLazyBind);
2774   }
2775 
2776   // Cast the argument to 'id'.
2777   value = Builder.CreateBitCast(value, Int8PtrTy);
2778 
2779   // Call objc_release.
2780   llvm::CallBase *call = EmitCallOrInvoke(fn, value);
2781 
2782   if (precise == ARCImpreciseLifetime) {
2783     call->setMetadata("clang.imprecise_release",
2784                       llvm::MDNode::get(Builder.getContext(), None));
2785   }
2786 }
2787 
2788 namespace {
2789   struct CallObjCAutoreleasePoolObject final : EHScopeStack::Cleanup {
2790     llvm::Value *Token;
2791 
2792     CallObjCAutoreleasePoolObject(llvm::Value *token) : Token(token) {}
2793 
2794     void Emit(CodeGenFunction &CGF, Flags flags) override {
2795       CGF.EmitObjCAutoreleasePoolPop(Token);
2796     }
2797   };
2798   struct CallObjCMRRAutoreleasePoolObject final : EHScopeStack::Cleanup {
2799     llvm::Value *Token;
2800 
2801     CallObjCMRRAutoreleasePoolObject(llvm::Value *token) : Token(token) {}
2802 
2803     void Emit(CodeGenFunction &CGF, Flags flags) override {
2804       CGF.EmitObjCMRRAutoreleasePoolPop(Token);
2805     }
2806   };
2807 }
2808 
2809 void CodeGenFunction::EmitObjCAutoreleasePoolCleanup(llvm::Value *Ptr) {
2810   if (CGM.getLangOpts().ObjCAutoRefCount)
2811     EHStack.pushCleanup<CallObjCAutoreleasePoolObject>(NormalCleanup, Ptr);
2812   else
2813     EHStack.pushCleanup<CallObjCMRRAutoreleasePoolObject>(NormalCleanup, Ptr);
2814 }
2815 
2816 static bool shouldRetainObjCLifetime(Qualifiers::ObjCLifetime lifetime) {
2817   switch (lifetime) {
2818   case Qualifiers::OCL_None:
2819   case Qualifiers::OCL_ExplicitNone:
2820   case Qualifiers::OCL_Strong:
2821   case Qualifiers::OCL_Autoreleasing:
2822     return true;
2823 
2824   case Qualifiers::OCL_Weak:
2825     return false;
2826   }
2827 
2828   llvm_unreachable("impossible lifetime!");
2829 }
2830 
2831 static TryEmitResult tryEmitARCRetainLoadOfScalar(CodeGenFunction &CGF,
2832                                                   LValue lvalue,
2833                                                   QualType type) {
2834   llvm::Value *result;
2835   bool shouldRetain = shouldRetainObjCLifetime(type.getObjCLifetime());
2836   if (shouldRetain) {
2837     result = CGF.EmitLoadOfLValue(lvalue, SourceLocation()).getScalarVal();
2838   } else {
2839     assert(type.getObjCLifetime() == Qualifiers::OCL_Weak);
2840     result = CGF.EmitARCLoadWeakRetained(lvalue.getAddress(CGF));
2841   }
2842   return TryEmitResult(result, !shouldRetain);
2843 }
2844 
2845 static TryEmitResult tryEmitARCRetainLoadOfScalar(CodeGenFunction &CGF,
2846                                                   const Expr *e) {
2847   e = e->IgnoreParens();
2848   QualType type = e->getType();
2849 
2850   // If we're loading retained from a __strong xvalue, we can avoid
2851   // an extra retain/release pair by zeroing out the source of this
2852   // "move" operation.
2853   if (e->isXValue() &&
2854       !type.isConstQualified() &&
2855       type.getObjCLifetime() == Qualifiers::OCL_Strong) {
2856     // Emit the lvalue.
2857     LValue lv = CGF.EmitLValue(e);
2858 
2859     // Load the object pointer.
2860     llvm::Value *result = CGF.EmitLoadOfLValue(lv,
2861                                                SourceLocation()).getScalarVal();
2862 
2863     // Set the source pointer to NULL.
2864     CGF.EmitStoreOfScalar(getNullForVariable(lv.getAddress(CGF)), lv);
2865 
2866     return TryEmitResult(result, true);
2867   }
2868 
2869   // As a very special optimization, in ARC++, if the l-value is the
2870   // result of a non-volatile assignment, do a simple retain of the
2871   // result of the call to objc_storeWeak instead of reloading.
2872   if (CGF.getLangOpts().CPlusPlus &&
2873       !type.isVolatileQualified() &&
2874       type.getObjCLifetime() == Qualifiers::OCL_Weak &&
2875       isa<BinaryOperator>(e) &&
2876       cast<BinaryOperator>(e)->getOpcode() == BO_Assign)
2877     return TryEmitResult(CGF.EmitScalarExpr(e), false);
2878 
2879   // Try to emit code for scalar constant instead of emitting LValue and
2880   // loading it because we are not guaranteed to have an l-value. One of such
2881   // cases is DeclRefExpr referencing non-odr-used constant-evaluated variable.
2882   if (const auto *decl_expr = dyn_cast<DeclRefExpr>(e)) {
2883     auto *DRE = const_cast<DeclRefExpr *>(decl_expr);
2884     if (CodeGenFunction::ConstantEmission constant = CGF.tryEmitAsConstant(DRE))
2885       return TryEmitResult(CGF.emitScalarConstant(constant, DRE),
2886                            !shouldRetainObjCLifetime(type.getObjCLifetime()));
2887   }
2888 
2889   return tryEmitARCRetainLoadOfScalar(CGF, CGF.EmitLValue(e), type);
2890 }
2891 
2892 typedef llvm::function_ref<llvm::Value *(CodeGenFunction &CGF,
2893                                          llvm::Value *value)>
2894   ValueTransform;
2895 
2896 /// Insert code immediately after a call.
2897 
2898 // FIXME: We should find a way to emit the runtime call immediately
2899 // after the call is emitted to eliminate the need for this function.
2900 static llvm::Value *emitARCOperationAfterCall(CodeGenFunction &CGF,
2901                                               llvm::Value *value,
2902                                               ValueTransform doAfterCall,
2903                                               ValueTransform doFallback) {
2904   CGBuilderTy::InsertPoint ip = CGF.Builder.saveIP();
2905 
2906   if (llvm::CallInst *call = dyn_cast<llvm::CallInst>(value)) {
2907     // Place the retain immediately following the call.
2908     CGF.Builder.SetInsertPoint(call->getParent(),
2909                                ++llvm::BasicBlock::iterator(call));
2910     value = doAfterCall(CGF, value);
2911   } else if (llvm::InvokeInst *invoke = dyn_cast<llvm::InvokeInst>(value)) {
2912     // Place the retain at the beginning of the normal destination block.
2913     llvm::BasicBlock *BB = invoke->getNormalDest();
2914     CGF.Builder.SetInsertPoint(BB, BB->begin());
2915     value = doAfterCall(CGF, value);
2916 
2917   // Bitcasts can arise because of related-result returns.  Rewrite
2918   // the operand.
2919   } else if (llvm::BitCastInst *bitcast = dyn_cast<llvm::BitCastInst>(value)) {
2920     // Change the insert point to avoid emitting the fall-back call after the
2921     // bitcast.
2922     CGF.Builder.SetInsertPoint(bitcast->getParent(), bitcast->getIterator());
2923     llvm::Value *operand = bitcast->getOperand(0);
2924     operand = emitARCOperationAfterCall(CGF, operand, doAfterCall, doFallback);
2925     bitcast->setOperand(0, operand);
2926     value = bitcast;
2927   } else {
2928     auto *phi = dyn_cast<llvm::PHINode>(value);
2929     if (phi && phi->getNumIncomingValues() == 2 &&
2930         isa<llvm::ConstantPointerNull>(phi->getIncomingValue(1)) &&
2931         isa<llvm::CallBase>(phi->getIncomingValue(0))) {
2932       // Handle phi instructions that are generated when it's necessary to check
2933       // whether the receiver of a message is null.
2934       llvm::Value *inVal = phi->getIncomingValue(0);
2935       inVal = emitARCOperationAfterCall(CGF, inVal, doAfterCall, doFallback);
2936       phi->setIncomingValue(0, inVal);
2937       value = phi;
2938     } else {
2939       // Generic fall-back case.
2940       // Retain using the non-block variant: we never need to do a copy
2941       // of a block that's been returned to us.
2942       value = doFallback(CGF, value);
2943     }
2944   }
2945 
2946   CGF.Builder.restoreIP(ip);
2947   return value;
2948 }
2949 
2950 /// Given that the given expression is some sort of call (which does
2951 /// not return retained), emit a retain following it.
2952 static llvm::Value *emitARCRetainCallResult(CodeGenFunction &CGF,
2953                                             const Expr *e) {
2954   llvm::Value *value = CGF.EmitScalarExpr(e);
2955   return emitARCOperationAfterCall(CGF, value,
2956            [](CodeGenFunction &CGF, llvm::Value *value) {
2957              return CGF.EmitARCRetainAutoreleasedReturnValue(value);
2958            },
2959            [](CodeGenFunction &CGF, llvm::Value *value) {
2960              return CGF.EmitARCRetainNonBlock(value);
2961            });
2962 }
2963 
2964 /// Given that the given expression is some sort of call (which does
2965 /// not return retained), perform an unsafeClaim following it.
2966 static llvm::Value *emitARCUnsafeClaimCallResult(CodeGenFunction &CGF,
2967                                                  const Expr *e) {
2968   llvm::Value *value = CGF.EmitScalarExpr(e);
2969   return emitARCOperationAfterCall(CGF, value,
2970            [](CodeGenFunction &CGF, llvm::Value *value) {
2971              return CGF.EmitARCUnsafeClaimAutoreleasedReturnValue(value);
2972            },
2973            [](CodeGenFunction &CGF, llvm::Value *value) {
2974              return value;
2975            });
2976 }
2977 
2978 llvm::Value *CodeGenFunction::EmitARCReclaimReturnedObject(const Expr *E,
2979                                                       bool allowUnsafeClaim) {
2980   if (allowUnsafeClaim &&
2981       CGM.getLangOpts().ObjCRuntime.hasARCUnsafeClaimAutoreleasedReturnValue()) {
2982     return emitARCUnsafeClaimCallResult(*this, E);
2983   } else {
2984     llvm::Value *value = emitARCRetainCallResult(*this, E);
2985     return EmitObjCConsumeObject(E->getType(), value);
2986   }
2987 }
2988 
2989 /// Determine whether it might be important to emit a separate
2990 /// objc_retain_block on the result of the given expression, or
2991 /// whether it's okay to just emit it in a +1 context.
2992 static bool shouldEmitSeparateBlockRetain(const Expr *e) {
2993   assert(e->getType()->isBlockPointerType());
2994   e = e->IgnoreParens();
2995 
2996   // For future goodness, emit block expressions directly in +1
2997   // contexts if we can.
2998   if (isa<BlockExpr>(e))
2999     return false;
3000 
3001   if (const CastExpr *cast = dyn_cast<CastExpr>(e)) {
3002     switch (cast->getCastKind()) {
3003     // Emitting these operations in +1 contexts is goodness.
3004     case CK_LValueToRValue:
3005     case CK_ARCReclaimReturnedObject:
3006     case CK_ARCConsumeObject:
3007     case CK_ARCProduceObject:
3008       return false;
3009 
3010     // These operations preserve a block type.
3011     case CK_NoOp:
3012     case CK_BitCast:
3013       return shouldEmitSeparateBlockRetain(cast->getSubExpr());
3014 
3015     // These operations are known to be bad (or haven't been considered).
3016     case CK_AnyPointerToBlockPointerCast:
3017     default:
3018       return true;
3019     }
3020   }
3021 
3022   return true;
3023 }
3024 
3025 namespace {
3026 /// A CRTP base class for emitting expressions of retainable object
3027 /// pointer type in ARC.
3028 template <typename Impl, typename Result> class ARCExprEmitter {
3029 protected:
3030   CodeGenFunction &CGF;
3031   Impl &asImpl() { return *static_cast<Impl*>(this); }
3032 
3033   ARCExprEmitter(CodeGenFunction &CGF) : CGF(CGF) {}
3034 
3035 public:
3036   Result visit(const Expr *e);
3037   Result visitCastExpr(const CastExpr *e);
3038   Result visitPseudoObjectExpr(const PseudoObjectExpr *e);
3039   Result visitBlockExpr(const BlockExpr *e);
3040   Result visitBinaryOperator(const BinaryOperator *e);
3041   Result visitBinAssign(const BinaryOperator *e);
3042   Result visitBinAssignUnsafeUnretained(const BinaryOperator *e);
3043   Result visitBinAssignAutoreleasing(const BinaryOperator *e);
3044   Result visitBinAssignWeak(const BinaryOperator *e);
3045   Result visitBinAssignStrong(const BinaryOperator *e);
3046 
3047   // Minimal implementation:
3048   //   Result visitLValueToRValue(const Expr *e)
3049   //   Result visitConsumeObject(const Expr *e)
3050   //   Result visitExtendBlockObject(const Expr *e)
3051   //   Result visitReclaimReturnedObject(const Expr *e)
3052   //   Result visitCall(const Expr *e)
3053   //   Result visitExpr(const Expr *e)
3054   //
3055   //   Result emitBitCast(Result result, llvm::Type *resultType)
3056   //   llvm::Value *getValueOfResult(Result result)
3057 };
3058 }
3059 
3060 /// Try to emit a PseudoObjectExpr under special ARC rules.
3061 ///
3062 /// This massively duplicates emitPseudoObjectRValue.
3063 template <typename Impl, typename Result>
3064 Result
3065 ARCExprEmitter<Impl,Result>::visitPseudoObjectExpr(const PseudoObjectExpr *E) {
3066   SmallVector<CodeGenFunction::OpaqueValueMappingData, 4> opaques;
3067 
3068   // Find the result expression.
3069   const Expr *resultExpr = E->getResultExpr();
3070   assert(resultExpr);
3071   Result result;
3072 
3073   for (PseudoObjectExpr::const_semantics_iterator
3074          i = E->semantics_begin(), e = E->semantics_end(); i != e; ++i) {
3075     const Expr *semantic = *i;
3076 
3077     // If this semantic expression is an opaque value, bind it
3078     // to the result of its source expression.
3079     if (const OpaqueValueExpr *ov = dyn_cast<OpaqueValueExpr>(semantic)) {
3080       typedef CodeGenFunction::OpaqueValueMappingData OVMA;
3081       OVMA opaqueData;
3082 
3083       // If this semantic is the result of the pseudo-object
3084       // expression, try to evaluate the source as +1.
3085       if (ov == resultExpr) {
3086         assert(!OVMA::shouldBindAsLValue(ov));
3087         result = asImpl().visit(ov->getSourceExpr());
3088         opaqueData = OVMA::bind(CGF, ov,
3089                             RValue::get(asImpl().getValueOfResult(result)));
3090 
3091       // Otherwise, just bind it.
3092       } else {
3093         opaqueData = OVMA::bind(CGF, ov, ov->getSourceExpr());
3094       }
3095       opaques.push_back(opaqueData);
3096 
3097     // Otherwise, if the expression is the result, evaluate it
3098     // and remember the result.
3099     } else if (semantic == resultExpr) {
3100       result = asImpl().visit(semantic);
3101 
3102     // Otherwise, evaluate the expression in an ignored context.
3103     } else {
3104       CGF.EmitIgnoredExpr(semantic);
3105     }
3106   }
3107 
3108   // Unbind all the opaques now.
3109   for (unsigned i = 0, e = opaques.size(); i != e; ++i)
3110     opaques[i].unbind(CGF);
3111 
3112   return result;
3113 }
3114 
3115 template <typename Impl, typename Result>
3116 Result ARCExprEmitter<Impl, Result>::visitBlockExpr(const BlockExpr *e) {
3117   // The default implementation just forwards the expression to visitExpr.
3118   return asImpl().visitExpr(e);
3119 }
3120 
3121 template <typename Impl, typename Result>
3122 Result ARCExprEmitter<Impl,Result>::visitCastExpr(const CastExpr *e) {
3123   switch (e->getCastKind()) {
3124 
3125   // No-op casts don't change the type, so we just ignore them.
3126   case CK_NoOp:
3127     return asImpl().visit(e->getSubExpr());
3128 
3129   // These casts can change the type.
3130   case CK_CPointerToObjCPointerCast:
3131   case CK_BlockPointerToObjCPointerCast:
3132   case CK_AnyPointerToBlockPointerCast:
3133   case CK_BitCast: {
3134     llvm::Type *resultType = CGF.ConvertType(e->getType());
3135     assert(e->getSubExpr()->getType()->hasPointerRepresentation());
3136     Result result = asImpl().visit(e->getSubExpr());
3137     return asImpl().emitBitCast(result, resultType);
3138   }
3139 
3140   // Handle some casts specially.
3141   case CK_LValueToRValue:
3142     return asImpl().visitLValueToRValue(e->getSubExpr());
3143   case CK_ARCConsumeObject:
3144     return asImpl().visitConsumeObject(e->getSubExpr());
3145   case CK_ARCExtendBlockObject:
3146     return asImpl().visitExtendBlockObject(e->getSubExpr());
3147   case CK_ARCReclaimReturnedObject:
3148     return asImpl().visitReclaimReturnedObject(e->getSubExpr());
3149 
3150   // Otherwise, use the default logic.
3151   default:
3152     return asImpl().visitExpr(e);
3153   }
3154 }
3155 
3156 template <typename Impl, typename Result>
3157 Result
3158 ARCExprEmitter<Impl,Result>::visitBinaryOperator(const BinaryOperator *e) {
3159   switch (e->getOpcode()) {
3160   case BO_Comma:
3161     CGF.EmitIgnoredExpr(e->getLHS());
3162     CGF.EnsureInsertPoint();
3163     return asImpl().visit(e->getRHS());
3164 
3165   case BO_Assign:
3166     return asImpl().visitBinAssign(e);
3167 
3168   default:
3169     return asImpl().visitExpr(e);
3170   }
3171 }
3172 
3173 template <typename Impl, typename Result>
3174 Result ARCExprEmitter<Impl,Result>::visitBinAssign(const BinaryOperator *e) {
3175   switch (e->getLHS()->getType().getObjCLifetime()) {
3176   case Qualifiers::OCL_ExplicitNone:
3177     return asImpl().visitBinAssignUnsafeUnretained(e);
3178 
3179   case Qualifiers::OCL_Weak:
3180     return asImpl().visitBinAssignWeak(e);
3181 
3182   case Qualifiers::OCL_Autoreleasing:
3183     return asImpl().visitBinAssignAutoreleasing(e);
3184 
3185   case Qualifiers::OCL_Strong:
3186     return asImpl().visitBinAssignStrong(e);
3187 
3188   case Qualifiers::OCL_None:
3189     return asImpl().visitExpr(e);
3190   }
3191   llvm_unreachable("bad ObjC ownership qualifier");
3192 }
3193 
3194 /// The default rule for __unsafe_unretained emits the RHS recursively,
3195 /// stores into the unsafe variable, and propagates the result outward.
3196 template <typename Impl, typename Result>
3197 Result ARCExprEmitter<Impl,Result>::
3198                     visitBinAssignUnsafeUnretained(const BinaryOperator *e) {
3199   // Recursively emit the RHS.
3200   // For __block safety, do this before emitting the LHS.
3201   Result result = asImpl().visit(e->getRHS());
3202 
3203   // Perform the store.
3204   LValue lvalue =
3205     CGF.EmitCheckedLValue(e->getLHS(), CodeGenFunction::TCK_Store);
3206   CGF.EmitStoreThroughLValue(RValue::get(asImpl().getValueOfResult(result)),
3207                              lvalue);
3208 
3209   return result;
3210 }
3211 
3212 template <typename Impl, typename Result>
3213 Result
3214 ARCExprEmitter<Impl,Result>::visitBinAssignAutoreleasing(const BinaryOperator *e) {
3215   return asImpl().visitExpr(e);
3216 }
3217 
3218 template <typename Impl, typename Result>
3219 Result
3220 ARCExprEmitter<Impl,Result>::visitBinAssignWeak(const BinaryOperator *e) {
3221   return asImpl().visitExpr(e);
3222 }
3223 
3224 template <typename Impl, typename Result>
3225 Result
3226 ARCExprEmitter<Impl,Result>::visitBinAssignStrong(const BinaryOperator *e) {
3227   return asImpl().visitExpr(e);
3228 }
3229 
3230 /// The general expression-emission logic.
3231 template <typename Impl, typename Result>
3232 Result ARCExprEmitter<Impl,Result>::visit(const Expr *e) {
3233   // We should *never* see a nested full-expression here, because if
3234   // we fail to emit at +1, our caller must not retain after we close
3235   // out the full-expression.  This isn't as important in the unsafe
3236   // emitter.
3237   assert(!isa<ExprWithCleanups>(e));
3238 
3239   // Look through parens, __extension__, generic selection, etc.
3240   e = e->IgnoreParens();
3241 
3242   // Handle certain kinds of casts.
3243   if (const CastExpr *ce = dyn_cast<CastExpr>(e)) {
3244     return asImpl().visitCastExpr(ce);
3245 
3246   // Handle the comma operator.
3247   } else if (auto op = dyn_cast<BinaryOperator>(e)) {
3248     return asImpl().visitBinaryOperator(op);
3249 
3250   // TODO: handle conditional operators here
3251 
3252   // For calls and message sends, use the retained-call logic.
3253   // Delegate inits are a special case in that they're the only
3254   // returns-retained expression that *isn't* surrounded by
3255   // a consume.
3256   } else if (isa<CallExpr>(e) ||
3257              (isa<ObjCMessageExpr>(e) &&
3258               !cast<ObjCMessageExpr>(e)->isDelegateInitCall())) {
3259     return asImpl().visitCall(e);
3260 
3261   // Look through pseudo-object expressions.
3262   } else if (const PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) {
3263     return asImpl().visitPseudoObjectExpr(pseudo);
3264   } else if (auto *be = dyn_cast<BlockExpr>(e))
3265     return asImpl().visitBlockExpr(be);
3266 
3267   return asImpl().visitExpr(e);
3268 }
3269 
3270 namespace {
3271 
3272 /// An emitter for +1 results.
3273 struct ARCRetainExprEmitter :
3274   public ARCExprEmitter<ARCRetainExprEmitter, TryEmitResult> {
3275 
3276   ARCRetainExprEmitter(CodeGenFunction &CGF) : ARCExprEmitter(CGF) {}
3277 
3278   llvm::Value *getValueOfResult(TryEmitResult result) {
3279     return result.getPointer();
3280   }
3281 
3282   TryEmitResult emitBitCast(TryEmitResult result, llvm::Type *resultType) {
3283     llvm::Value *value = result.getPointer();
3284     value = CGF.Builder.CreateBitCast(value, resultType);
3285     result.setPointer(value);
3286     return result;
3287   }
3288 
3289   TryEmitResult visitLValueToRValue(const Expr *e) {
3290     return tryEmitARCRetainLoadOfScalar(CGF, e);
3291   }
3292 
3293   /// For consumptions, just emit the subexpression and thus elide
3294   /// the retain/release pair.
3295   TryEmitResult visitConsumeObject(const Expr *e) {
3296     llvm::Value *result = CGF.EmitScalarExpr(e);
3297     return TryEmitResult(result, true);
3298   }
3299 
3300   TryEmitResult visitBlockExpr(const BlockExpr *e) {
3301     TryEmitResult result = visitExpr(e);
3302     // Avoid the block-retain if this is a block literal that doesn't need to be
3303     // copied to the heap.
3304     if (e->getBlockDecl()->canAvoidCopyToHeap())
3305       result.setInt(true);
3306     return result;
3307   }
3308 
3309   /// Block extends are net +0.  Naively, we could just recurse on
3310   /// the subexpression, but actually we need to ensure that the
3311   /// value is copied as a block, so there's a little filter here.
3312   TryEmitResult visitExtendBlockObject(const Expr *e) {
3313     llvm::Value *result; // will be a +0 value
3314 
3315     // If we can't safely assume the sub-expression will produce a
3316     // block-copied value, emit the sub-expression at +0.
3317     if (shouldEmitSeparateBlockRetain(e)) {
3318       result = CGF.EmitScalarExpr(e);
3319 
3320     // Otherwise, try to emit the sub-expression at +1 recursively.
3321     } else {
3322       TryEmitResult subresult = asImpl().visit(e);
3323 
3324       // If that produced a retained value, just use that.
3325       if (subresult.getInt()) {
3326         return subresult;
3327       }
3328 
3329       // Otherwise it's +0.
3330       result = subresult.getPointer();
3331     }
3332 
3333     // Retain the object as a block.
3334     result = CGF.EmitARCRetainBlock(result, /*mandatory*/ true);
3335     return TryEmitResult(result, true);
3336   }
3337 
3338   /// For reclaims, emit the subexpression as a retained call and
3339   /// skip the consumption.
3340   TryEmitResult visitReclaimReturnedObject(const Expr *e) {
3341     llvm::Value *result = emitARCRetainCallResult(CGF, e);
3342     return TryEmitResult(result, true);
3343   }
3344 
3345   /// When we have an undecorated call, retroactively do a claim.
3346   TryEmitResult visitCall(const Expr *e) {
3347     llvm::Value *result = emitARCRetainCallResult(CGF, e);
3348     return TryEmitResult(result, true);
3349   }
3350 
3351   // TODO: maybe special-case visitBinAssignWeak?
3352 
3353   TryEmitResult visitExpr(const Expr *e) {
3354     // We didn't find an obvious production, so emit what we've got and
3355     // tell the caller that we didn't manage to retain.
3356     llvm::Value *result = CGF.EmitScalarExpr(e);
3357     return TryEmitResult(result, false);
3358   }
3359 };
3360 }
3361 
3362 static TryEmitResult
3363 tryEmitARCRetainScalarExpr(CodeGenFunction &CGF, const Expr *e) {
3364   return ARCRetainExprEmitter(CGF).visit(e);
3365 }
3366 
3367 static llvm::Value *emitARCRetainLoadOfScalar(CodeGenFunction &CGF,
3368                                                 LValue lvalue,
3369                                                 QualType type) {
3370   TryEmitResult result = tryEmitARCRetainLoadOfScalar(CGF, lvalue, type);
3371   llvm::Value *value = result.getPointer();
3372   if (!result.getInt())
3373     value = CGF.EmitARCRetain(type, value);
3374   return value;
3375 }
3376 
3377 /// EmitARCRetainScalarExpr - Semantically equivalent to
3378 /// EmitARCRetainObject(e->getType(), EmitScalarExpr(e)), but making a
3379 /// best-effort attempt to peephole expressions that naturally produce
3380 /// retained objects.
3381 llvm::Value *CodeGenFunction::EmitARCRetainScalarExpr(const Expr *e) {
3382   // The retain needs to happen within the full-expression.
3383   if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
3384     RunCleanupsScope scope(*this);
3385     return EmitARCRetainScalarExpr(cleanups->getSubExpr());
3386   }
3387 
3388   TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e);
3389   llvm::Value *value = result.getPointer();
3390   if (!result.getInt())
3391     value = EmitARCRetain(e->getType(), value);
3392   return value;
3393 }
3394 
3395 llvm::Value *
3396 CodeGenFunction::EmitARCRetainAutoreleaseScalarExpr(const Expr *e) {
3397   // The retain needs to happen within the full-expression.
3398   if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
3399     RunCleanupsScope scope(*this);
3400     return EmitARCRetainAutoreleaseScalarExpr(cleanups->getSubExpr());
3401   }
3402 
3403   TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e);
3404   llvm::Value *value = result.getPointer();
3405   if (result.getInt())
3406     value = EmitARCAutorelease(value);
3407   else
3408     value = EmitARCRetainAutorelease(e->getType(), value);
3409   return value;
3410 }
3411 
3412 llvm::Value *CodeGenFunction::EmitARCExtendBlockObject(const Expr *e) {
3413   llvm::Value *result;
3414   bool doRetain;
3415 
3416   if (shouldEmitSeparateBlockRetain(e)) {
3417     result = EmitScalarExpr(e);
3418     doRetain = true;
3419   } else {
3420     TryEmitResult subresult = tryEmitARCRetainScalarExpr(*this, e);
3421     result = subresult.getPointer();
3422     doRetain = !subresult.getInt();
3423   }
3424 
3425   if (doRetain)
3426     result = EmitARCRetainBlock(result, /*mandatory*/ true);
3427   return EmitObjCConsumeObject(e->getType(), result);
3428 }
3429 
3430 llvm::Value *CodeGenFunction::EmitObjCThrowOperand(const Expr *expr) {
3431   // In ARC, retain and autorelease the expression.
3432   if (getLangOpts().ObjCAutoRefCount) {
3433     // Do so before running any cleanups for the full-expression.
3434     // EmitARCRetainAutoreleaseScalarExpr does this for us.
3435     return EmitARCRetainAutoreleaseScalarExpr(expr);
3436   }
3437 
3438   // Otherwise, use the normal scalar-expression emission.  The
3439   // exception machinery doesn't do anything special with the
3440   // exception like retaining it, so there's no safety associated with
3441   // only running cleanups after the throw has started, and when it
3442   // matters it tends to be substantially inferior code.
3443   return EmitScalarExpr(expr);
3444 }
3445 
3446 namespace {
3447 
3448 /// An emitter for assigning into an __unsafe_unretained context.
3449 struct ARCUnsafeUnretainedExprEmitter :
3450   public ARCExprEmitter<ARCUnsafeUnretainedExprEmitter, llvm::Value*> {
3451 
3452   ARCUnsafeUnretainedExprEmitter(CodeGenFunction &CGF) : ARCExprEmitter(CGF) {}
3453 
3454   llvm::Value *getValueOfResult(llvm::Value *value) {
3455     return value;
3456   }
3457 
3458   llvm::Value *emitBitCast(llvm::Value *value, llvm::Type *resultType) {
3459     return CGF.Builder.CreateBitCast(value, resultType);
3460   }
3461 
3462   llvm::Value *visitLValueToRValue(const Expr *e) {
3463     return CGF.EmitScalarExpr(e);
3464   }
3465 
3466   /// For consumptions, just emit the subexpression and perform the
3467   /// consumption like normal.
3468   llvm::Value *visitConsumeObject(const Expr *e) {
3469     llvm::Value *value = CGF.EmitScalarExpr(e);
3470     return CGF.EmitObjCConsumeObject(e->getType(), value);
3471   }
3472 
3473   /// No special logic for block extensions.  (This probably can't
3474   /// actually happen in this emitter, though.)
3475   llvm::Value *visitExtendBlockObject(const Expr *e) {
3476     return CGF.EmitARCExtendBlockObject(e);
3477   }
3478 
3479   /// For reclaims, perform an unsafeClaim if that's enabled.
3480   llvm::Value *visitReclaimReturnedObject(const Expr *e) {
3481     return CGF.EmitARCReclaimReturnedObject(e, /*unsafe*/ true);
3482   }
3483 
3484   /// When we have an undecorated call, just emit it without adding
3485   /// the unsafeClaim.
3486   llvm::Value *visitCall(const Expr *e) {
3487     return CGF.EmitScalarExpr(e);
3488   }
3489 
3490   /// Just do normal scalar emission in the default case.
3491   llvm::Value *visitExpr(const Expr *e) {
3492     return CGF.EmitScalarExpr(e);
3493   }
3494 };
3495 }
3496 
3497 static llvm::Value *emitARCUnsafeUnretainedScalarExpr(CodeGenFunction &CGF,
3498                                                       const Expr *e) {
3499   return ARCUnsafeUnretainedExprEmitter(CGF).visit(e);
3500 }
3501 
3502 /// EmitARCUnsafeUnretainedScalarExpr - Semantically equivalent to
3503 /// immediately releasing the resut of EmitARCRetainScalarExpr, but
3504 /// avoiding any spurious retains, including by performing reclaims
3505 /// with objc_unsafeClaimAutoreleasedReturnValue.
3506 llvm::Value *CodeGenFunction::EmitARCUnsafeUnretainedScalarExpr(const Expr *e) {
3507   // Look through full-expressions.
3508   if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
3509     RunCleanupsScope scope(*this);
3510     return emitARCUnsafeUnretainedScalarExpr(*this, cleanups->getSubExpr());
3511   }
3512 
3513   return emitARCUnsafeUnretainedScalarExpr(*this, e);
3514 }
3515 
3516 std::pair<LValue,llvm::Value*>
3517 CodeGenFunction::EmitARCStoreUnsafeUnretained(const BinaryOperator *e,
3518                                               bool ignored) {
3519   // Evaluate the RHS first.  If we're ignoring the result, assume
3520   // that we can emit at an unsafe +0.
3521   llvm::Value *value;
3522   if (ignored) {
3523     value = EmitARCUnsafeUnretainedScalarExpr(e->getRHS());
3524   } else {
3525     value = EmitScalarExpr(e->getRHS());
3526   }
3527 
3528   // Emit the LHS and perform the store.
3529   LValue lvalue = EmitLValue(e->getLHS());
3530   EmitStoreOfScalar(value, lvalue);
3531 
3532   return std::pair<LValue,llvm::Value*>(std::move(lvalue), value);
3533 }
3534 
3535 std::pair<LValue,llvm::Value*>
3536 CodeGenFunction::EmitARCStoreStrong(const BinaryOperator *e,
3537                                     bool ignored) {
3538   // Evaluate the RHS first.
3539   TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e->getRHS());
3540   llvm::Value *value = result.getPointer();
3541 
3542   bool hasImmediateRetain = result.getInt();
3543 
3544   // If we didn't emit a retained object, and the l-value is of block
3545   // type, then we need to emit the block-retain immediately in case
3546   // it invalidates the l-value.
3547   if (!hasImmediateRetain && e->getType()->isBlockPointerType()) {
3548     value = EmitARCRetainBlock(value, /*mandatory*/ false);
3549     hasImmediateRetain = true;
3550   }
3551 
3552   LValue lvalue = EmitLValue(e->getLHS());
3553 
3554   // If the RHS was emitted retained, expand this.
3555   if (hasImmediateRetain) {
3556     llvm::Value *oldValue = EmitLoadOfScalar(lvalue, SourceLocation());
3557     EmitStoreOfScalar(value, lvalue);
3558     EmitARCRelease(oldValue, lvalue.isARCPreciseLifetime());
3559   } else {
3560     value = EmitARCStoreStrong(lvalue, value, ignored);
3561   }
3562 
3563   return std::pair<LValue,llvm::Value*>(lvalue, value);
3564 }
3565 
3566 std::pair<LValue,llvm::Value*>
3567 CodeGenFunction::EmitARCStoreAutoreleasing(const BinaryOperator *e) {
3568   llvm::Value *value = EmitARCRetainAutoreleaseScalarExpr(e->getRHS());
3569   LValue lvalue = EmitLValue(e->getLHS());
3570 
3571   EmitStoreOfScalar(value, lvalue);
3572 
3573   return std::pair<LValue,llvm::Value*>(lvalue, value);
3574 }
3575 
3576 void CodeGenFunction::EmitObjCAutoreleasePoolStmt(
3577                                           const ObjCAutoreleasePoolStmt &ARPS) {
3578   const Stmt *subStmt = ARPS.getSubStmt();
3579   const CompoundStmt &S = cast<CompoundStmt>(*subStmt);
3580 
3581   CGDebugInfo *DI = getDebugInfo();
3582   if (DI)
3583     DI->EmitLexicalBlockStart(Builder, S.getLBracLoc());
3584 
3585   // Keep track of the current cleanup stack depth.
3586   RunCleanupsScope Scope(*this);
3587   if (CGM.getLangOpts().ObjCRuntime.hasNativeARC()) {
3588     llvm::Value *token = EmitObjCAutoreleasePoolPush();
3589     EHStack.pushCleanup<CallObjCAutoreleasePoolObject>(NormalCleanup, token);
3590   } else {
3591     llvm::Value *token = EmitObjCMRRAutoreleasePoolPush();
3592     EHStack.pushCleanup<CallObjCMRRAutoreleasePoolObject>(NormalCleanup, token);
3593   }
3594 
3595   for (const auto *I : S.body())
3596     EmitStmt(I);
3597 
3598   if (DI)
3599     DI->EmitLexicalBlockEnd(Builder, S.getRBracLoc());
3600 }
3601 
3602 /// EmitExtendGCLifetime - Given a pointer to an Objective-C object,
3603 /// make sure it survives garbage collection until this point.
3604 void CodeGenFunction::EmitExtendGCLifetime(llvm::Value *object) {
3605   // We just use an inline assembly.
3606   llvm::FunctionType *extenderType
3607     = llvm::FunctionType::get(VoidTy, VoidPtrTy, RequiredArgs::All);
3608   llvm::InlineAsm *extender = llvm::InlineAsm::get(extenderType,
3609                                                    /* assembly */ "",
3610                                                    /* constraints */ "r",
3611                                                    /* side effects */ true);
3612 
3613   object = Builder.CreateBitCast(object, VoidPtrTy);
3614   EmitNounwindRuntimeCall(extender, object);
3615 }
3616 
3617 /// GenerateObjCAtomicSetterCopyHelperFunction - Given a c++ object type with
3618 /// non-trivial copy assignment function, produce following helper function.
3619 /// static void copyHelper(Ty *dest, const Ty *source) { *dest = *source; }
3620 ///
3621 llvm::Constant *
3622 CodeGenFunction::GenerateObjCAtomicSetterCopyHelperFunction(
3623                                         const ObjCPropertyImplDecl *PID) {
3624   if (!getLangOpts().CPlusPlus ||
3625       !getLangOpts().ObjCRuntime.hasAtomicCopyHelper())
3626     return nullptr;
3627   QualType Ty = PID->getPropertyIvarDecl()->getType();
3628   if (!Ty->isRecordType())
3629     return nullptr;
3630   const ObjCPropertyDecl *PD = PID->getPropertyDecl();
3631   if ((!(PD->getPropertyAttributes() & ObjCPropertyAttribute::kind_atomic)))
3632     return nullptr;
3633   llvm::Constant *HelperFn = nullptr;
3634   if (hasTrivialSetExpr(PID))
3635     return nullptr;
3636   assert(PID->getSetterCXXAssignment() && "SetterCXXAssignment - null");
3637   if ((HelperFn = CGM.getAtomicSetterHelperFnMap(Ty)))
3638     return HelperFn;
3639 
3640   ASTContext &C = getContext();
3641   IdentifierInfo *II
3642     = &CGM.getContext().Idents.get("__assign_helper_atomic_property_");
3643 
3644   QualType ReturnTy = C.VoidTy;
3645   QualType DestTy = C.getPointerType(Ty);
3646   QualType SrcTy = Ty;
3647   SrcTy.addConst();
3648   SrcTy = C.getPointerType(SrcTy);
3649 
3650   SmallVector<QualType, 2> ArgTys;
3651   ArgTys.push_back(DestTy);
3652   ArgTys.push_back(SrcTy);
3653   QualType FunctionTy = C.getFunctionType(ReturnTy, ArgTys, {});
3654 
3655   FunctionDecl *FD = FunctionDecl::Create(
3656       C, C.getTranslationUnitDecl(), SourceLocation(), SourceLocation(), II,
3657       FunctionTy, nullptr, SC_Static, false, false);
3658 
3659   FunctionArgList args;
3660   ImplicitParamDecl DstDecl(C, FD, SourceLocation(), /*Id=*/nullptr, DestTy,
3661                             ImplicitParamDecl::Other);
3662   args.push_back(&DstDecl);
3663   ImplicitParamDecl SrcDecl(C, FD, SourceLocation(), /*Id=*/nullptr, SrcTy,
3664                             ImplicitParamDecl::Other);
3665   args.push_back(&SrcDecl);
3666 
3667   const CGFunctionInfo &FI =
3668       CGM.getTypes().arrangeBuiltinFunctionDeclaration(ReturnTy, args);
3669 
3670   llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
3671 
3672   llvm::Function *Fn =
3673     llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
3674                            "__assign_helper_atomic_property_",
3675                            &CGM.getModule());
3676 
3677   CGM.SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
3678 
3679   StartFunction(FD, ReturnTy, Fn, FI, args);
3680 
3681   DeclRefExpr DstExpr(C, &DstDecl, false, DestTy, VK_RValue, SourceLocation());
3682   UnaryOperator *DST = UnaryOperator::Create(
3683       C, &DstExpr, UO_Deref, DestTy->getPointeeType(), VK_LValue, OK_Ordinary,
3684       SourceLocation(), false, FPOptionsOverride());
3685 
3686   DeclRefExpr SrcExpr(C, &SrcDecl, false, SrcTy, VK_RValue, SourceLocation());
3687   UnaryOperator *SRC = UnaryOperator::Create(
3688       C, &SrcExpr, UO_Deref, SrcTy->getPointeeType(), VK_LValue, OK_Ordinary,
3689       SourceLocation(), false, FPOptionsOverride());
3690 
3691   Expr *Args[2] = {DST, SRC};
3692   CallExpr *CalleeExp = cast<CallExpr>(PID->getSetterCXXAssignment());
3693   CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
3694       C, OO_Equal, CalleeExp->getCallee(), Args, DestTy->getPointeeType(),
3695       VK_LValue, SourceLocation(), FPOptionsOverride());
3696 
3697   EmitStmt(TheCall);
3698 
3699   FinishFunction();
3700   HelperFn = llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
3701   CGM.setAtomicSetterHelperFnMap(Ty, HelperFn);
3702   return HelperFn;
3703 }
3704 
3705 llvm::Constant *
3706 CodeGenFunction::GenerateObjCAtomicGetterCopyHelperFunction(
3707                                             const ObjCPropertyImplDecl *PID) {
3708   if (!getLangOpts().CPlusPlus ||
3709       !getLangOpts().ObjCRuntime.hasAtomicCopyHelper())
3710     return nullptr;
3711   const ObjCPropertyDecl *PD = PID->getPropertyDecl();
3712   QualType Ty = PD->getType();
3713   if (!Ty->isRecordType())
3714     return nullptr;
3715   if ((!(PD->getPropertyAttributes() & ObjCPropertyAttribute::kind_atomic)))
3716     return nullptr;
3717   llvm::Constant *HelperFn = nullptr;
3718   if (hasTrivialGetExpr(PID))
3719     return nullptr;
3720   assert(PID->getGetterCXXConstructor() && "getGetterCXXConstructor - null");
3721   if ((HelperFn = CGM.getAtomicGetterHelperFnMap(Ty)))
3722     return HelperFn;
3723 
3724   ASTContext &C = getContext();
3725   IdentifierInfo *II =
3726       &CGM.getContext().Idents.get("__copy_helper_atomic_property_");
3727 
3728   QualType ReturnTy = C.VoidTy;
3729   QualType DestTy = C.getPointerType(Ty);
3730   QualType SrcTy = Ty;
3731   SrcTy.addConst();
3732   SrcTy = C.getPointerType(SrcTy);
3733 
3734   SmallVector<QualType, 2> ArgTys;
3735   ArgTys.push_back(DestTy);
3736   ArgTys.push_back(SrcTy);
3737   QualType FunctionTy = C.getFunctionType(ReturnTy, ArgTys, {});
3738 
3739   FunctionDecl *FD = FunctionDecl::Create(
3740       C, C.getTranslationUnitDecl(), SourceLocation(), SourceLocation(), II,
3741       FunctionTy, nullptr, SC_Static, false, false);
3742 
3743   FunctionArgList args;
3744   ImplicitParamDecl DstDecl(C, FD, SourceLocation(), /*Id=*/nullptr, DestTy,
3745                             ImplicitParamDecl::Other);
3746   args.push_back(&DstDecl);
3747   ImplicitParamDecl SrcDecl(C, FD, SourceLocation(), /*Id=*/nullptr, SrcTy,
3748                             ImplicitParamDecl::Other);
3749   args.push_back(&SrcDecl);
3750 
3751   const CGFunctionInfo &FI =
3752       CGM.getTypes().arrangeBuiltinFunctionDeclaration(ReturnTy, args);
3753 
3754   llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
3755 
3756   llvm::Function *Fn = llvm::Function::Create(
3757       LTy, llvm::GlobalValue::InternalLinkage, "__copy_helper_atomic_property_",
3758       &CGM.getModule());
3759 
3760   CGM.SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
3761 
3762   StartFunction(FD, ReturnTy, Fn, FI, args);
3763 
3764   DeclRefExpr SrcExpr(getContext(), &SrcDecl, false, SrcTy, VK_RValue,
3765                       SourceLocation());
3766 
3767   UnaryOperator *SRC = UnaryOperator::Create(
3768       C, &SrcExpr, UO_Deref, SrcTy->getPointeeType(), VK_LValue, OK_Ordinary,
3769       SourceLocation(), false, FPOptionsOverride());
3770 
3771   CXXConstructExpr *CXXConstExpr =
3772     cast<CXXConstructExpr>(PID->getGetterCXXConstructor());
3773 
3774   SmallVector<Expr*, 4> ConstructorArgs;
3775   ConstructorArgs.push_back(SRC);
3776   ConstructorArgs.append(std::next(CXXConstExpr->arg_begin()),
3777                          CXXConstExpr->arg_end());
3778 
3779   CXXConstructExpr *TheCXXConstructExpr =
3780     CXXConstructExpr::Create(C, Ty, SourceLocation(),
3781                              CXXConstExpr->getConstructor(),
3782                              CXXConstExpr->isElidable(),
3783                              ConstructorArgs,
3784                              CXXConstExpr->hadMultipleCandidates(),
3785                              CXXConstExpr->isListInitialization(),
3786                              CXXConstExpr->isStdInitListInitialization(),
3787                              CXXConstExpr->requiresZeroInitialization(),
3788                              CXXConstExpr->getConstructionKind(),
3789                              SourceRange());
3790 
3791   DeclRefExpr DstExpr(getContext(), &DstDecl, false, DestTy, VK_RValue,
3792                       SourceLocation());
3793 
3794   RValue DV = EmitAnyExpr(&DstExpr);
3795   CharUnits Alignment
3796     = getContext().getTypeAlignInChars(TheCXXConstructExpr->getType());
3797   EmitAggExpr(TheCXXConstructExpr,
3798               AggValueSlot::forAddr(Address(DV.getScalarVal(), Alignment),
3799                                     Qualifiers(),
3800                                     AggValueSlot::IsDestructed,
3801                                     AggValueSlot::DoesNotNeedGCBarriers,
3802                                     AggValueSlot::IsNotAliased,
3803                                     AggValueSlot::DoesNotOverlap));
3804 
3805   FinishFunction();
3806   HelperFn = llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
3807   CGM.setAtomicGetterHelperFnMap(Ty, HelperFn);
3808   return HelperFn;
3809 }
3810 
3811 llvm::Value *
3812 CodeGenFunction::EmitBlockCopyAndAutorelease(llvm::Value *Block, QualType Ty) {
3813   // Get selectors for retain/autorelease.
3814   IdentifierInfo *CopyID = &getContext().Idents.get("copy");
3815   Selector CopySelector =
3816       getContext().Selectors.getNullarySelector(CopyID);
3817   IdentifierInfo *AutoreleaseID = &getContext().Idents.get("autorelease");
3818   Selector AutoreleaseSelector =
3819       getContext().Selectors.getNullarySelector(AutoreleaseID);
3820 
3821   // Emit calls to retain/autorelease.
3822   CGObjCRuntime &Runtime = CGM.getObjCRuntime();
3823   llvm::Value *Val = Block;
3824   RValue Result;
3825   Result = Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
3826                                        Ty, CopySelector,
3827                                        Val, CallArgList(), nullptr, nullptr);
3828   Val = Result.getScalarVal();
3829   Result = Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
3830                                        Ty, AutoreleaseSelector,
3831                                        Val, CallArgList(), nullptr, nullptr);
3832   Val = Result.getScalarVal();
3833   return Val;
3834 }
3835 
3836 static unsigned getBaseMachOPlatformID(const llvm::Triple &TT) {
3837   switch (TT.getOS()) {
3838   case llvm::Triple::Darwin:
3839   case llvm::Triple::MacOSX:
3840     return llvm::MachO::PLATFORM_MACOS;
3841   case llvm::Triple::IOS:
3842     return llvm::MachO::PLATFORM_IOS;
3843   case llvm::Triple::TvOS:
3844     return llvm::MachO::PLATFORM_TVOS;
3845   case llvm::Triple::WatchOS:
3846     return llvm::MachO::PLATFORM_WATCHOS;
3847   default:
3848     return /*Unknown platform*/ 0;
3849   }
3850 }
3851 
3852 static llvm::Value *emitIsPlatformVersionAtLeast(CodeGenFunction &CGF,
3853                                                  const VersionTuple &Version) {
3854   CodeGenModule &CGM = CGF.CGM;
3855   // Note: we intend to support multi-platform version checks, so reserve
3856   // the room for a dual platform checking invocation that will be
3857   // implemented in the future.
3858   llvm::SmallVector<llvm::Value *, 8> Args;
3859 
3860   auto EmitArgs = [&](const VersionTuple &Version, const llvm::Triple &TT) {
3861     Optional<unsigned> Min = Version.getMinor(), SMin = Version.getSubminor();
3862     Args.push_back(
3863         llvm::ConstantInt::get(CGM.Int32Ty, getBaseMachOPlatformID(TT)));
3864     Args.push_back(llvm::ConstantInt::get(CGM.Int32Ty, Version.getMajor()));
3865     Args.push_back(llvm::ConstantInt::get(CGM.Int32Ty, Min ? *Min : 0));
3866     Args.push_back(llvm::ConstantInt::get(CGM.Int32Ty, SMin ? *SMin : 0));
3867   };
3868 
3869   assert(!Version.empty() && "unexpected empty version");
3870   EmitArgs(Version, CGM.getTarget().getTriple());
3871 
3872   if (!CGM.IsPlatformVersionAtLeastFn) {
3873     llvm::FunctionType *FTy = llvm::FunctionType::get(
3874         CGM.Int32Ty, {CGM.Int32Ty, CGM.Int32Ty, CGM.Int32Ty, CGM.Int32Ty},
3875         false);
3876     CGM.IsPlatformVersionAtLeastFn =
3877         CGM.CreateRuntimeFunction(FTy, "__isPlatformVersionAtLeast");
3878   }
3879 
3880   llvm::Value *Check =
3881       CGF.EmitNounwindRuntimeCall(CGM.IsPlatformVersionAtLeastFn, Args);
3882   return CGF.Builder.CreateICmpNE(Check,
3883                                   llvm::Constant::getNullValue(CGM.Int32Ty));
3884 }
3885 
3886 llvm::Value *
3887 CodeGenFunction::EmitBuiltinAvailable(const VersionTuple &Version) {
3888   // Darwin uses the new __isPlatformVersionAtLeast family of routines.
3889   if (CGM.getTarget().getTriple().isOSDarwin())
3890     return emitIsPlatformVersionAtLeast(*this, Version);
3891 
3892   if (!CGM.IsOSVersionAtLeastFn) {
3893     llvm::FunctionType *FTy =
3894         llvm::FunctionType::get(Int32Ty, {Int32Ty, Int32Ty, Int32Ty}, false);
3895     CGM.IsOSVersionAtLeastFn =
3896         CGM.CreateRuntimeFunction(FTy, "__isOSVersionAtLeast");
3897   }
3898 
3899   Optional<unsigned> Min = Version.getMinor(), SMin = Version.getSubminor();
3900   llvm::Value *Args[] = {
3901       llvm::ConstantInt::get(CGM.Int32Ty, Version.getMajor()),
3902       llvm::ConstantInt::get(CGM.Int32Ty, Min ? *Min : 0),
3903       llvm::ConstantInt::get(CGM.Int32Ty, SMin ? *SMin : 0),
3904   };
3905 
3906   llvm::Value *CallRes =
3907       EmitNounwindRuntimeCall(CGM.IsOSVersionAtLeastFn, Args);
3908 
3909   return Builder.CreateICmpNE(CallRes, llvm::Constant::getNullValue(Int32Ty));
3910 }
3911 
3912 static bool isFoundationNeededForDarwinAvailabilityCheck(
3913     const llvm::Triple &TT, const VersionTuple &TargetVersion) {
3914   VersionTuple FoundationDroppedInVersion;
3915   switch (TT.getOS()) {
3916   case llvm::Triple::IOS:
3917   case llvm::Triple::TvOS:
3918     FoundationDroppedInVersion = VersionTuple(/*Major=*/13);
3919     break;
3920   case llvm::Triple::WatchOS:
3921     FoundationDroppedInVersion = VersionTuple(/*Major=*/6);
3922     break;
3923   case llvm::Triple::Darwin:
3924   case llvm::Triple::MacOSX:
3925     FoundationDroppedInVersion = VersionTuple(/*Major=*/10, /*Minor=*/15);
3926     break;
3927   default:
3928     llvm_unreachable("Unexpected OS");
3929   }
3930   return TargetVersion < FoundationDroppedInVersion;
3931 }
3932 
3933 void CodeGenModule::emitAtAvailableLinkGuard() {
3934   if (!IsPlatformVersionAtLeastFn)
3935     return;
3936   // @available requires CoreFoundation only on Darwin.
3937   if (!Target.getTriple().isOSDarwin())
3938     return;
3939   // @available doesn't need Foundation on macOS 10.15+, iOS/tvOS 13+, or
3940   // watchOS 6+.
3941   if (!isFoundationNeededForDarwinAvailabilityCheck(
3942           Target.getTriple(), Target.getPlatformMinVersion()))
3943     return;
3944   // Add -framework CoreFoundation to the linker commands. We still want to
3945   // emit the core foundation reference down below because otherwise if
3946   // CoreFoundation is not used in the code, the linker won't link the
3947   // framework.
3948   auto &Context = getLLVMContext();
3949   llvm::Metadata *Args[2] = {llvm::MDString::get(Context, "-framework"),
3950                              llvm::MDString::get(Context, "CoreFoundation")};
3951   LinkerOptionsMetadata.push_back(llvm::MDNode::get(Context, Args));
3952   // Emit a reference to a symbol from CoreFoundation to ensure that
3953   // CoreFoundation is linked into the final binary.
3954   llvm::FunctionType *FTy =
3955       llvm::FunctionType::get(Int32Ty, {VoidPtrTy}, false);
3956   llvm::FunctionCallee CFFunc =
3957       CreateRuntimeFunction(FTy, "CFBundleGetVersionNumber");
3958 
3959   llvm::FunctionType *CheckFTy = llvm::FunctionType::get(VoidTy, {}, false);
3960   llvm::FunctionCallee CFLinkCheckFuncRef = CreateRuntimeFunction(
3961       CheckFTy, "__clang_at_available_requires_core_foundation_framework",
3962       llvm::AttributeList(), /*Local=*/true);
3963   llvm::Function *CFLinkCheckFunc =
3964       cast<llvm::Function>(CFLinkCheckFuncRef.getCallee()->stripPointerCasts());
3965   if (CFLinkCheckFunc->empty()) {
3966     CFLinkCheckFunc->setLinkage(llvm::GlobalValue::LinkOnceAnyLinkage);
3967     CFLinkCheckFunc->setVisibility(llvm::GlobalValue::HiddenVisibility);
3968     CodeGenFunction CGF(*this);
3969     CGF.Builder.SetInsertPoint(CGF.createBasicBlock("", CFLinkCheckFunc));
3970     CGF.EmitNounwindRuntimeCall(CFFunc,
3971                                 llvm::Constant::getNullValue(VoidPtrTy));
3972     CGF.Builder.CreateUnreachable();
3973     addCompilerUsedGlobal(CFLinkCheckFunc);
3974   }
3975 }
3976 
3977 CGObjCRuntime::~CGObjCRuntime() {}
3978