YQ Connector: support managed ClickHouse

Со стороны dqrun можно обратиться к инстансу коннектора, который работает на streaming стенде, и извлечь данные из облачного CH.

1 files changed, 4030 insertions, 0 deletions

diff --git a/contrib/libs/clang14/lib/CodeGen/CGObjC.cpp b/contrib/libs/clang14/lib/CodeGen/CGObjC.cpp
new file mode 100644
index 0000000000..8cc609186f
--- /dev/null
+++ b/contrib/libs/clang14/lib/CodeGen/CGObjC.cpp
@@ -0,0 +1,4030 @@
+//===---- CGObjC.cpp - Emit LLVM Code for Objective-C ---------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code to emit Objective-C code as LLVM code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CGDebugInfo.h"
+#include "CGObjCRuntime.h"
+#include "CodeGenFunction.h"
+#include "CodeGenModule.h"
+#include "ConstantEmitter.h"
+#include "TargetInfo.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Attr.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/StmtObjC.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/CodeGen/CGFunctionInfo.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/ObjCARCUtil.h"
+#include "llvm/BinaryFormat/MachO.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/InlineAsm.h"
+using namespace clang;
+using namespace CodeGen;
+
+typedef llvm::PointerIntPair<llvm::Value*,1,bool> TryEmitResult;
+static TryEmitResult
+tryEmitARCRetainScalarExpr(CodeGenFunction &CGF, const Expr *e);
+static RValue AdjustObjCObjectType(CodeGenFunction &CGF,
+                                   QualType ET,
+                                   RValue Result);
+
+/// Given the address of a variable of pointer type, find the correct
+/// null to store into it.
+static llvm::Constant *getNullForVariable(Address addr) {
+  llvm::Type *type = addr.getElementType();
+  return llvm::ConstantPointerNull::get(cast<llvm::PointerType>(type));
+}
+
+/// Emits an instance of NSConstantString representing the object.
+llvm::Value *CodeGenFunction::EmitObjCStringLiteral(const ObjCStringLiteral *E)
+{
+  llvm::Constant *C =
+      CGM.getObjCRuntime().GenerateConstantString(E->getString()).getPointer();
+  // FIXME: This bitcast should just be made an invariant on the Runtime.
+  return llvm::ConstantExpr::getBitCast(C, ConvertType(E->getType()));
+}
+
+/// EmitObjCBoxedExpr - This routine generates code to call
+/// the appropriate expression boxing method. This will either be
+/// one of +[NSNumber numberWith<Type>:], or +[NSString stringWithUTF8String:],
+/// or [NSValue valueWithBytes:objCType:].
+///
+llvm::Value *
+CodeGenFunction::EmitObjCBoxedExpr(const ObjCBoxedExpr *E) {
+  // Generate the correct selector for this literal's concrete type.
+  // Get the method.
+  const ObjCMethodDecl *BoxingMethod = E->getBoxingMethod();
+  const Expr *SubExpr = E->getSubExpr();
+
+  if (E->isExpressibleAsConstantInitializer()) {
+    ConstantEmitter ConstEmitter(CGM);
+    return ConstEmitter.tryEmitAbstract(E, E->getType());
+  }
+
+  assert(BoxingMethod->isClassMethod() && "BoxingMethod must be a class method");
+  Selector Sel = BoxingMethod->getSelector();
+
+  // Generate a reference to the class pointer, which will be the receiver.
+  // Assumes that the method was introduced in the class that should be
+  // messaged (avoids pulling it out of the result type).
+  CGObjCRuntime &Runtime = CGM.getObjCRuntime();
+  const ObjCInterfaceDecl *ClassDecl = BoxingMethod->getClassInterface();
+  llvm::Value *Receiver = Runtime.GetClass(*this, ClassDecl);
+
+  CallArgList Args;
+  const ParmVarDecl *ArgDecl = *BoxingMethod->param_begin();
+  QualType ArgQT = ArgDecl->getType().getUnqualifiedType();
+
+  // ObjCBoxedExpr supports boxing of structs and unions
+  // via [NSValue valueWithBytes:objCType:]
+  const QualType ValueType(SubExpr->getType().getCanonicalType());
+  if (ValueType->isObjCBoxableRecordType()) {
+    // Emit CodeGen for first parameter
+    // and cast value to correct type
+    Address Temporary = CreateMemTemp(SubExpr->getType());
+    EmitAnyExprToMem(SubExpr, Temporary, Qualifiers(), /*isInit*/ true);
+    Address BitCast = Builder.CreateBitCast(Temporary, ConvertType(ArgQT));
+    Args.add(RValue::get(BitCast.getPointer()), ArgQT);
+
+    // Create char array to store type encoding
+    std::string Str;
+    getContext().getObjCEncodingForType(ValueType, Str);
+    llvm::Constant *GV = CGM.GetAddrOfConstantCString(Str).getPointer();
+
+    // Cast type encoding to correct type
+    const ParmVarDecl *EncodingDecl = BoxingMethod->parameters()[1];
+    QualType EncodingQT = EncodingDecl->getType().getUnqualifiedType();
+    llvm::Value *Cast = Builder.CreateBitCast(GV, ConvertType(EncodingQT));
+
+    Args.add(RValue::get(Cast), EncodingQT);
+  } else {
+    Args.add(EmitAnyExpr(SubExpr), ArgQT);
+  }
+
+  RValue result = Runtime.GenerateMessageSend(
+      *this, ReturnValueSlot(), BoxingMethod->getReturnType(), Sel, Receiver,
+      Args, ClassDecl, BoxingMethod);
+  return Builder.CreateBitCast(result.getScalarVal(),
+                               ConvertType(E->getType()));
+}
+
+llvm::Value *CodeGenFunction::EmitObjCCollectionLiteral(const Expr *E,
+                                    const ObjCMethodDecl *MethodWithObjects) {
+  ASTContext &Context = CGM.getContext();
+  const ObjCDictionaryLiteral *DLE = nullptr;
+  const ObjCArrayLiteral *ALE = dyn_cast<ObjCArrayLiteral>(E);
+  if (!ALE)
+    DLE = cast<ObjCDictionaryLiteral>(E);
+
+  // Optimize empty collections by referencing constants, when available.
+  uint64_t NumElements =
+    ALE ? ALE->getNumElements() : DLE->getNumElements();
+  if (NumElements == 0 && CGM.getLangOpts().ObjCRuntime.hasEmptyCollections()) {
+    StringRef ConstantName = ALE ? "__NSArray0__" : "__NSDictionary0__";
+    QualType IdTy(CGM.getContext().getObjCIdType());
+    llvm::Constant *Constant =
+        CGM.CreateRuntimeVariable(ConvertType(IdTy), ConstantName);
+    LValue LV = MakeNaturalAlignAddrLValue(Constant, IdTy);
+    llvm::Value *Ptr = EmitLoadOfScalar(LV, E->getBeginLoc());
+    cast<llvm::LoadInst>(Ptr)->setMetadata(
+        CGM.getModule().getMDKindID("invariant.load"),
+        llvm::MDNode::get(getLLVMContext(), None));
+    return Builder.CreateBitCast(Ptr, ConvertType(E->getType()));
+  }
+
+  // Compute the type of the array we're initializing.
+  llvm::APInt APNumElements(Context.getTypeSize(Context.getSizeType()),
+                            NumElements);
+  QualType ElementType = Context.getObjCIdType().withConst();
+  QualType ElementArrayType
+    = Context.getConstantArrayType(ElementType, APNumElements, nullptr,
+                                   ArrayType::Normal, /*IndexTypeQuals=*/0);
+
+  // Allocate the temporary array(s).
+  Address Objects = CreateMemTemp(ElementArrayType, "objects");
+  Address Keys = Address::invalid();
+  if (DLE)
+    Keys = CreateMemTemp(ElementArrayType, "keys");
+
+  // In ARC, we may need to do extra work to keep all the keys and
+  // values alive until after the call.
+  SmallVector<llvm::Value *, 16> NeededObjects;
+  bool TrackNeededObjects =
+    (getLangOpts().ObjCAutoRefCount &&
+    CGM.getCodeGenOpts().OptimizationLevel != 0);
+
+  // Perform the actual initialialization of the array(s).
+  for (uint64_t i = 0; i < NumElements; i++) {
+    if (ALE) {
+      // Emit the element and store it to the appropriate array slot.
+      const Expr *Rhs = ALE->getElement(i);
+      LValue LV = MakeAddrLValue(Builder.CreateConstArrayGEP(Objects, i),
+                                 ElementType, AlignmentSource::Decl);
+
+      llvm::Value *value = EmitScalarExpr(Rhs);
+      EmitStoreThroughLValue(RValue::get(value), LV, true);
+      if (TrackNeededObjects) {
+        NeededObjects.push_back(value);
+      }
+    } else {
+      // Emit the key and store it to the appropriate array slot.
+      const Expr *Key = DLE->getKeyValueElement(i).Key;
+      LValue KeyLV = MakeAddrLValue(Builder.CreateConstArrayGEP(Keys, i),
+                                    ElementType, AlignmentSource::Decl);
+      llvm::Value *keyValue = EmitScalarExpr(Key);
+      EmitStoreThroughLValue(RValue::get(keyValue), KeyLV, /*isInit=*/true);
+
+      // Emit the value and store it to the appropriate array slot.
+      const Expr *Value = DLE->getKeyValueElement(i).Value;
+      LValue ValueLV = MakeAddrLValue(Builder.CreateConstArrayGEP(Objects, i),
+                                      ElementType, AlignmentSource::Decl);
+      llvm::Value *valueValue = EmitScalarExpr(Value);
+      EmitStoreThroughLValue(RValue::get(valueValue), ValueLV, /*isInit=*/true);
+      if (TrackNeededObjects) {
+        NeededObjects.push_back(keyValue);
+        NeededObjects.push_back(valueValue);
+      }
+    }
+  }
+
+  // Generate the argument list.
+  CallArgList Args;
+  ObjCMethodDecl::param_const_iterator PI = MethodWithObjects->param_begin();
+  const ParmVarDecl *argDecl = *PI++;
+  QualType ArgQT = argDecl->getType().getUnqualifiedType();
+  Args.add(RValue::get(Objects.getPointer()), ArgQT);
+  if (DLE) {
+    argDecl = *PI++;
+    ArgQT = argDecl->getType().getUnqualifiedType();
+    Args.add(RValue::get(Keys.getPointer()), ArgQT);
+  }
+  argDecl = *PI;
+  ArgQT = argDecl->getType().getUnqualifiedType();
+  llvm::Value *Count =
+    llvm::ConstantInt::get(CGM.getTypes().ConvertType(ArgQT), NumElements);
+  Args.add(RValue::get(Count), ArgQT);
+
+  // Generate a reference to the class pointer, which will be the receiver.
+  Selector Sel = MethodWithObjects->getSelector();
+  QualType ResultType = E->getType();
+  const ObjCObjectPointerType *InterfacePointerType
+    = ResultType->getAsObjCInterfacePointerType();
+  ObjCInterfaceDecl *Class
+    = InterfacePointerType->getObjectType()->getInterface();
+  CGObjCRuntime &Runtime = CGM.getObjCRuntime();
+  llvm::Value *Receiver = Runtime.GetClass(*this, Class);
+
+  // Generate the message send.
+  RValue result = Runtime.GenerateMessageSend(
+      *this, ReturnValueSlot(), MethodWithObjects->getReturnType(), Sel,
+      Receiver, Args, Class, MethodWithObjects);
+
+  // The above message send needs these objects, but in ARC they are
+  // passed in a buffer that is essentially __unsafe_unretained.
+  // Therefore we must prevent the optimizer from releasing them until
+  // after the call.
+  if (TrackNeededObjects) {
+    EmitARCIntrinsicUse(NeededObjects);
+  }
+
+  return Builder.CreateBitCast(result.getScalarVal(),
+                               ConvertType(E->getType()));
+}
+
+llvm::Value *CodeGenFunction::EmitObjCArrayLiteral(const ObjCArrayLiteral *E) {
+  return EmitObjCCollectionLiteral(E, E->getArrayWithObjectsMethod());
+}
+
+llvm::Value *CodeGenFunction::EmitObjCDictionaryLiteral(
+                                            const ObjCDictionaryLiteral *E) {
+  return EmitObjCCollectionLiteral(E, E->getDictWithObjectsMethod());
+}
+
+/// Emit a selector.
+llvm::Value *CodeGenFunction::EmitObjCSelectorExpr(const ObjCSelectorExpr *E) {
+  // Untyped selector.
+  // Note that this implementation allows for non-constant strings to be passed
+  // as arguments to @selector().  Currently, the only thing preventing this
+  // behaviour is the type checking in the front end.
+  return CGM.getObjCRuntime().GetSelector(*this, E->getSelector());
+}
+
+llvm::Value *CodeGenFunction::EmitObjCProtocolExpr(const ObjCProtocolExpr *E) {
+  // FIXME: This should pass the Decl not the name.
+  return CGM.getObjCRuntime().GenerateProtocolRef(*this, E->getProtocol());
+}
+
+/// Adjust the type of an Objective-C object that doesn't match up due
+/// to type erasure at various points, e.g., related result types or the use
+/// of parameterized classes.
+static RValue AdjustObjCObjectType(CodeGenFunction &CGF, QualType ExpT,
+                                   RValue Result) {
+  if (!ExpT->isObjCRetainableType())
+    return Result;
+
+  // If the converted types are the same, we're done.
+  llvm::Type *ExpLLVMTy = CGF.ConvertType(ExpT);
+  if (ExpLLVMTy == Result.getScalarVal()->getType())
+    return Result;
+
+  // We have applied a substitution. Cast the rvalue appropriately.
+  return RValue::get(CGF.Builder.CreateBitCast(Result.getScalarVal(),
+                                               ExpLLVMTy));
+}
+
+/// Decide whether to extend the lifetime of the receiver of a
+/// returns-inner-pointer message.
+static bool
+shouldExtendReceiverForInnerPointerMessage(const ObjCMessageExpr *message) {
+  switch (message->getReceiverKind()) {
+
+  // For a normal instance message, we should extend unless the
+  // receiver is loaded from a variable with precise lifetime.
+  case ObjCMessageExpr::Instance: {
+    const Expr *receiver = message->getInstanceReceiver();
+
+    // Look through OVEs.
+    if (auto opaque = dyn_cast<OpaqueValueExpr>(receiver)) {
+      if (opaque->getSourceExpr())
+        receiver = opaque->getSourceExpr()->IgnoreParens();
+    }
+
+    const ImplicitCastExpr *ice = dyn_cast<ImplicitCastExpr>(receiver);
+    if (!ice || ice->getCastKind() != CK_LValueToRValue) return true;
+    receiver = ice->getSubExpr()->IgnoreParens();
+
+    // Look through OVEs.
+    if (auto opaque = dyn_cast<OpaqueValueExpr>(receiver)) {
+      if (opaque->getSourceExpr())
+        receiver = opaque->getSourceExpr()->IgnoreParens();
+    }
+
+    // Only __strong variables.
+    if (receiver->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
+      return true;
+
+    // All ivars and fields have precise lifetime.
+    if (isa<MemberExpr>(receiver) || isa<ObjCIvarRefExpr>(receiver))
+      return false;
+
+    // Otherwise, check for variables.
+    const DeclRefExpr *declRef = dyn_cast<DeclRefExpr>(ice->getSubExpr());
+    if (!declRef) return true;
+    const VarDecl *var = dyn_cast<VarDecl>(declRef->getDecl());
+    if (!var) return true;
+
+    // All variables have precise lifetime except local variables with
+    // automatic storage duration that aren't specially marked.
+    return (var->hasLocalStorage() &&
+            !var->hasAttr<ObjCPreciseLifetimeAttr>());
+  }
+
+  case ObjCMessageExpr::Class:
+  case ObjCMessageExpr::SuperClass:
+    // It's never necessary for class objects.
+    return false;
+
+  case ObjCMessageExpr::SuperInstance:
+    // We generally assume that 'self' lives throughout a method call.
+    return false;
+  }
+
+  llvm_unreachable("invalid receiver kind");
+}
+
+/// Given an expression of ObjC pointer type, check whether it was
+/// immediately loaded from an ARC __weak l-value.
+static const Expr *findWeakLValue(const Expr *E) {
+  assert(E->getType()->isObjCRetainableType());
+  E = E->IgnoreParens();
+  if (auto CE = dyn_cast<CastExpr>(E)) {
+    if (CE->getCastKind() == CK_LValueToRValue) {
+      if (CE->getSubExpr()->getType().getObjCLifetime() == Qualifiers::OCL_Weak)
+        return CE->getSubExpr();
+    }
+  }
+
+  return nullptr;
+}
+
+/// The ObjC runtime may provide entrypoints that are likely to be faster
+/// than an ordinary message send of the appropriate selector.
+///
+/// The entrypoints are guaranteed to be equivalent to just sending the
+/// corresponding message.  If the entrypoint is implemented naively as just a
+/// message send, using it is a trade-off: it sacrifices a few cycles of
+/// overhead to save a small amount of code.  However, it's possible for
+/// runtimes to detect and special-case classes that use "standard"
+/// behavior; if that's dynamically a large proportion of all objects, using
+/// the entrypoint will also be faster than using a message send.
+///
+/// If the runtime does support a required entrypoint, then this method will
+/// generate a call and return the resulting value.  Otherwise it will return
+/// None and the caller can generate a msgSend instead.
+static Optional<llvm::Value *>
+tryGenerateSpecializedMessageSend(CodeGenFunction &CGF, QualType ResultType,
+                                  llvm::Value *Receiver,
+                                  const CallArgList& Args, Selector Sel,
+                                  const ObjCMethodDecl *method,
+                                  bool isClassMessage) {
+  auto &CGM = CGF.CGM;
+  if (!CGM.getCodeGenOpts().ObjCConvertMessagesToRuntimeCalls)
+    return None;
+
+  auto &Runtime = CGM.getLangOpts().ObjCRuntime;
+  switch (Sel.getMethodFamily()) {
+  case OMF_alloc:
+    if (isClassMessage &&
+        Runtime.shouldUseRuntimeFunctionsForAlloc() &&
+        ResultType->isObjCObjectPointerType()) {
+        // [Foo alloc] -> objc_alloc(Foo) or
+        // [self alloc] -> objc_alloc(self)
+        if (Sel.isUnarySelector() && Sel.getNameForSlot(0) == "alloc")
+          return CGF.EmitObjCAlloc(Receiver, CGF.ConvertType(ResultType));
+        // [Foo allocWithZone:nil] -> objc_allocWithZone(Foo) or
+        // [self allocWithZone:nil] -> objc_allocWithZone(self)
+        if (Sel.isKeywordSelector() && Sel.getNumArgs() == 1 &&
+            Args.size() == 1 && Args.front().getType()->isPointerType() &&
+            Sel.getNameForSlot(0) == "allocWithZone") {
+          const llvm::Value* arg = Args.front().getKnownRValue().getScalarVal();
+          if (isa<llvm::ConstantPointerNull>(arg))
+            return CGF.EmitObjCAllocWithZone(Receiver,
+                                             CGF.ConvertType(ResultType));
+          return None;
+        }
+    }
+    break;
+
+  case OMF_autorelease:
+    if (ResultType->isObjCObjectPointerType() &&
+        CGM.getLangOpts().getGC() == LangOptions::NonGC &&
+        Runtime.shouldUseARCFunctionsForRetainRelease())
+      return CGF.EmitObjCAutorelease(Receiver, CGF.ConvertType(ResultType));
+    break;
+
+  case OMF_retain:
+    if (ResultType->isObjCObjectPointerType() &&
+        CGM.getLangOpts().getGC() == LangOptions::NonGC &&
+        Runtime.shouldUseARCFunctionsForRetainRelease())
+      return CGF.EmitObjCRetainNonBlock(Receiver, CGF.ConvertType(ResultType));
+    break;
+
+  case OMF_release:
+    if (ResultType->isVoidType() &&
+        CGM.getLangOpts().getGC() == LangOptions::NonGC &&
+        Runtime.shouldUseARCFunctionsForRetainRelease()) {
+      CGF.EmitObjCRelease(Receiver, ARCPreciseLifetime);
+      return nullptr;
+    }
+    break;
+
+  default:
+    break;
+  }
+  return None;
+}
+
+CodeGen::RValue CGObjCRuntime::GeneratePossiblySpecializedMessageSend(
+    CodeGenFunction &CGF, ReturnValueSlot Return, QualType ResultType,
+    Selector Sel, llvm::Value *Receiver, const CallArgList &Args,
+    const ObjCInterfaceDecl *OID, const ObjCMethodDecl *Method,
+    bool isClassMessage) {
+  if (Optional<llvm::Value *> SpecializedResult =
+          tryGenerateSpecializedMessageSend(CGF, ResultType, Receiver, Args,
+                                            Sel, Method, isClassMessage)) {
+    return RValue::get(SpecializedResult.getValue());
+  }
+  return GenerateMessageSend(CGF, Return, ResultType, Sel, Receiver, Args, OID,
+                             Method);
+}
+
+static void AppendFirstImpliedRuntimeProtocols(
+    const ObjCProtocolDecl *PD,
+    llvm::UniqueVector<const ObjCProtocolDecl *> &PDs) {
+  if (!PD->isNonRuntimeProtocol()) {
+    const auto *Can = PD->getCanonicalDecl();
+    PDs.insert(Can);
+    return;
+  }
+
+  for (const auto *ParentPD : PD->protocols())
+    AppendFirstImpliedRuntimeProtocols(ParentPD, PDs);
+}
+
+std::vector<const ObjCProtocolDecl *>
+CGObjCRuntime::GetRuntimeProtocolList(ObjCProtocolDecl::protocol_iterator begin,
+                                      ObjCProtocolDecl::protocol_iterator end) {
+  std::vector<const ObjCProtocolDecl *> RuntimePds;
+  llvm::DenseSet<const ObjCProtocolDecl *> NonRuntimePDs;
+
+  for (; begin != end; ++begin) {
+    const auto *It = *begin;
+    const auto *Can = It->getCanonicalDecl();
+    if (Can->isNonRuntimeProtocol())
+      NonRuntimePDs.insert(Can);
+    else
+      RuntimePds.push_back(Can);
+  }
+
+  // If there are no non-runtime protocols then we can just stop now.
+  if (NonRuntimePDs.empty())
+    return RuntimePds;
+
+  // Else we have to search through the non-runtime protocol's inheritancy
+  // hierarchy DAG stopping whenever a branch either finds a runtime protocol or
+  // a non-runtime protocol without any parents. These are the "first-implied"
+  // protocols from a non-runtime protocol.
+  llvm::UniqueVector<const ObjCProtocolDecl *> FirstImpliedProtos;
+  for (const auto *PD : NonRuntimePDs)
+    AppendFirstImpliedRuntimeProtocols(PD, FirstImpliedProtos);
+
+  // Walk the Runtime list to get all protocols implied via the inclusion of
+  // this protocol, e.g. all protocols it inherits from including itself.
+  llvm::DenseSet<const ObjCProtocolDecl *> AllImpliedProtocols;
+  for (const auto *PD : RuntimePds) {
+    const auto *Can = PD->getCanonicalDecl();
+    AllImpliedProtocols.insert(Can);
+    Can->getImpliedProtocols(AllImpliedProtocols);
+  }
+
+  // Similar to above, walk the list of first-implied protocols to find the set
+  // all the protocols implied excluding the listed protocols themselves since
+  // they are not yet a part of the `RuntimePds` list.
+  for (const auto *PD : FirstImpliedProtos) {
+    PD->getImpliedProtocols(AllImpliedProtocols);
+  }
+
+  // From the first-implied list we have to finish building the final protocol
+  // list. If a protocol in the first-implied list was already implied via some
+  // inheritance path through some other protocols then it would be redundant to
+  // add it here and so we skip over it.
+  for (const auto *PD : FirstImpliedProtos) {
+    if (!AllImpliedProtocols.contains(PD)) {
+      RuntimePds.push_back(PD);
+    }
+  }
+
+  return RuntimePds;
+}
+
+/// Instead of '[[MyClass alloc] init]', try to generate
+/// 'objc_alloc_init(MyClass)'. This provides a code size improvement on the
+/// caller side, as well as the optimized objc_alloc.
+static Optional<llvm::Value *>
+tryEmitSpecializedAllocInit(CodeGenFunction &CGF, const ObjCMessageExpr *OME) {
+  auto &Runtime = CGF.getLangOpts().ObjCRuntime;
+  if (!Runtime.shouldUseRuntimeFunctionForCombinedAllocInit())
+    return None;
+
+  // Match the exact pattern '[[MyClass alloc] init]'.
+  Selector Sel = OME->getSelector();
+  if (OME->getReceiverKind() != ObjCMessageExpr::Instance ||
+      !OME->getType()->isObjCObjectPointerType() || !Sel.isUnarySelector() ||
+      Sel.getNameForSlot(0) != "init")
+    return None;
+
+  // Okay, this is '[receiver init]', check if 'receiver' is '[cls alloc]'
+  // with 'cls' a Class.
+  auto *SubOME =
+      dyn_cast<ObjCMessageExpr>(OME->getInstanceReceiver()->IgnoreParenCasts());
+  if (!SubOME)
+    return None;
+  Selector SubSel = SubOME->getSelector();
+
+  if (!SubOME->getType()->isObjCObjectPointerType() ||
+      !SubSel.isUnarySelector() || SubSel.getNameForSlot(0) != "alloc")
+    return None;
+
+  llvm::Value *Receiver = nullptr;
+  switch (SubOME->getReceiverKind()) {
+  case ObjCMessageExpr::Instance:
+    if (!SubOME->getInstanceReceiver()->getType()->isObjCClassType())
+      return None;
+    Receiver = CGF.EmitScalarExpr(SubOME->getInstanceReceiver());
+    break;
+
+  case ObjCMessageExpr::Class: {
+    QualType ReceiverType = SubOME->getClassReceiver();
+    const ObjCObjectType *ObjTy = ReceiverType->castAs<ObjCObjectType>();
+    const ObjCInterfaceDecl *ID = ObjTy->getInterface();
+    assert(ID && "null interface should be impossible here");
+    Receiver = CGF.CGM.getObjCRuntime().GetClass(CGF, ID);
+    break;
+  }
+  case ObjCMessageExpr::SuperInstance:
+  case ObjCMessageExpr::SuperClass:
+    return None;
+  }
+
+  return CGF.EmitObjCAllocInit(Receiver, CGF.ConvertType(OME->getType()));
+}
+
+RValue CodeGenFunction::EmitObjCMessageExpr(const ObjCMessageExpr *E,
+                                            ReturnValueSlot Return) {
+  // Only the lookup mechanism and first two arguments of the method
+  // implementation vary between runtimes.  We can get the receiver and
+  // arguments in generic code.
+
+  bool isDelegateInit = E->isDelegateInitCall();
+
+  const ObjCMethodDecl *method = E->getMethodDecl();
+
+  // If the method is -retain, and the receiver's being loaded from
+  // a __weak variable, peephole the entire operation to objc_loadWeakRetained.
+  if (method && E->getReceiverKind() == ObjCMessageExpr::Instance &&
+      method->getMethodFamily() == OMF_retain) {
+    if (auto lvalueExpr = findWeakLValue(E->getInstanceReceiver())) {
+      LValue lvalue = EmitLValue(lvalueExpr);
+      llvm::Value *result = EmitARCLoadWeakRetained(lvalue.getAddress(*this));
+      return AdjustObjCObjectType(*this, E->getType(), RValue::get(result));
+    }
+  }
+
+  if (Optional<llvm::Value *> Val = tryEmitSpecializedAllocInit(*this, E))
+    return AdjustObjCObjectType(*this, E->getType(), RValue::get(*Val));
+
+  // We don't retain the receiver in delegate init calls, and this is
+  // safe because the receiver value is always loaded from 'self',
+  // which we zero out.  We don't want to Block_copy block receivers,
+  // though.
+  bool retainSelf =
+    (!isDelegateInit &&
+     CGM.getLangOpts().ObjCAutoRefCount &&
+     method &&
+     method->hasAttr<NSConsumesSelfAttr>());
+
+  CGObjCRuntime &Runtime = CGM.getObjCRuntime();
+  bool isSuperMessage = false;
+  bool isClassMessage = false;
+  ObjCInterfaceDecl *OID = nullptr;
+  // Find the receiver
+  QualType ReceiverType;
+  llvm::Value *Receiver = nullptr;
+  switch (E->getReceiverKind()) {
+  case ObjCMessageExpr::Instance:
+    ReceiverType = E->getInstanceReceiver()->getType();
+    isClassMessage = ReceiverType->isObjCClassType();
+    if (retainSelf) {
+      TryEmitResult ter = tryEmitARCRetainScalarExpr(*this,
+                                                   E->getInstanceReceiver());
+      Receiver = ter.getPointer();
+      if (ter.getInt()) retainSelf = false;
+    } else
+      Receiver = EmitScalarExpr(E->getInstanceReceiver());
+    break;
+
+  case ObjCMessageExpr::Class: {
+    ReceiverType = E->getClassReceiver();
+    OID = ReceiverType->castAs<ObjCObjectType>()->getInterface();
+    assert(OID && "Invalid Objective-C class message send");
+    Receiver = Runtime.GetClass(*this, OID);
+    isClassMessage = true;
+    break;
+  }
+
+  case ObjCMessageExpr::SuperInstance:
+    ReceiverType = E->getSuperType();
+    Receiver = LoadObjCSelf();
+    isSuperMessage = true;
+    break;
+
+  case ObjCMessageExpr::SuperClass:
+    ReceiverType = E->getSuperType();
+    Receiver = LoadObjCSelf();
+    isSuperMessage = true;
+    isClassMessage = true;
+    break;
+  }
+
+  if (retainSelf)
+    Receiver = EmitARCRetainNonBlock(Receiver);
+
+  // In ARC, we sometimes want to "extend the lifetime"
+  // (i.e. retain+autorelease) of receivers of returns-inner-pointer
+  // messages.
+  if (getLangOpts().ObjCAutoRefCount && method &&
+      method->hasAttr<ObjCReturnsInnerPointerAttr>() &&
+      shouldExtendReceiverForInnerPointerMessage(E))
+    Receiver = EmitARCRetainAutorelease(ReceiverType, Receiver);
+
+  QualType ResultType = method ? method->getReturnType() : E->getType();
+
+  CallArgList Args;
+  EmitCallArgs(Args, method, E->arguments(), /*AC*/AbstractCallee(method));
+
+  // For delegate init calls in ARC, do an unsafe store of null into
+  // self.  This represents the call taking direct ownership of that
+  // value.  We have to do this after emitting the other call
+  // arguments because they might also reference self, but we don't
+  // have to worry about any of them modifying self because that would
+  // be an undefined read and write of an object in unordered
+  // expressions.
+  if (isDelegateInit) {
+    assert(getLangOpts().ObjCAutoRefCount &&
+           "delegate init calls should only be marked in ARC");
+
+    // Do an unsafe store of null into self.
+    Address selfAddr =
+      GetAddrOfLocalVar(cast<ObjCMethodDecl>(CurCodeDecl)->getSelfDecl());
+    Builder.CreateStore(getNullForVariable(selfAddr), selfAddr);
+  }
+
+  RValue result;
+  if (isSuperMessage) {
+    // super is only valid in an Objective-C method
+    const ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(CurFuncDecl);
+    bool isCategoryImpl = isa<ObjCCategoryImplDecl>(OMD->getDeclContext());
+    result = Runtime.GenerateMessageSendSuper(*this, Return, ResultType,
+                                              E->getSelector(),
+                                              OMD->getClassInterface(),
+                                              isCategoryImpl,
+                                              Receiver,
+                                              isClassMessage,
+                                              Args,
+                                              method);
+  } else {
+    // Call runtime methods directly if we can.
+    result = Runtime.GeneratePossiblySpecializedMessageSend(
+        *this, Return, ResultType, E->getSelector(), Receiver, Args, OID,
+        method, isClassMessage);
+  }
+
+  // For delegate init calls in ARC, implicitly store the result of
+  // the call back into self.  This takes ownership of the value.
+  if (isDelegateInit) {
+    Address selfAddr =
+      GetAddrOfLocalVar(cast<ObjCMethodDecl>(CurCodeDecl)->getSelfDecl());
+    llvm::Value *newSelf = result.getScalarVal();
+
+    // The delegate return type isn't necessarily a matching type; in
+    // fact, it's quite likely to be 'id'.
+    llvm::Type *selfTy = selfAddr.getElementType();
+    newSelf = Builder.CreateBitCast(newSelf, selfTy);
+
+    Builder.CreateStore(newSelf, selfAddr);
+  }
+
+  return AdjustObjCObjectType(*this, E->getType(), result);
+}
+
+namespace {
+struct FinishARCDealloc final : EHScopeStack::Cleanup {
+  void Emit(CodeGenFunction &CGF, Flags flags) override {
+    const ObjCMethodDecl *method = cast<ObjCMethodDecl>(CGF.CurCodeDecl);
+
+    const ObjCImplDecl *impl = cast<ObjCImplDecl>(method->getDeclContext());
+    const ObjCInterfaceDecl *iface = impl->getClassInterface();
+    if (!iface->getSuperClass()) return;
+
+    bool isCategory = isa<ObjCCategoryImplDecl>(impl);
+
+    // Call [super dealloc] if we have a superclass.
+    llvm::Value *self = CGF.LoadObjCSelf();
+
+    CallArgList args;
+    CGF.CGM.getObjCRuntime().GenerateMessageSendSuper(CGF, ReturnValueSlot(),
+                                                      CGF.getContext().VoidTy,
+                                                      method->getSelector(),
+                                                      iface,
+                                                      isCategory,
+                                                      self,
+                                                      /*is class msg*/ false,
+                                                      args,
+                                                      method);
+  }
+};
+}
+
+/// StartObjCMethod - Begin emission of an ObjCMethod. This generates
+/// the LLVM function and sets the other context used by
+/// CodeGenFunction.
+void CodeGenFunction::StartObjCMethod(const ObjCMethodDecl *OMD,
+                                      const ObjCContainerDecl *CD) {
+  SourceLocation StartLoc = OMD->getBeginLoc();
+  FunctionArgList args;
+  // Check if we should generate debug info for this method.
+  if (OMD->hasAttr<NoDebugAttr>())
+    DebugInfo = nullptr; // disable debug info indefinitely for this function
+
+  llvm::Function *Fn = CGM.getObjCRuntime().GenerateMethod(OMD, CD);
+
+  const CGFunctionInfo &FI = CGM.getTypes().arrangeObjCMethodDeclaration(OMD);
+  if (OMD->isDirectMethod()) {
+    Fn->setVisibility(llvm::Function::HiddenVisibility);
+    CGM.SetLLVMFunctionAttributes(OMD, FI, Fn, /*IsThunk=*/false);
+    CGM.SetLLVMFunctionAttributesForDefinition(OMD, Fn);
+  } else {
+    CGM.SetInternalFunctionAttributes(OMD, Fn, FI);
+  }
+
+  args.push_back(OMD->getSelfDecl());
+  args.push_back(OMD->getCmdDecl());
+
+  args.append(OMD->param_begin(), OMD->param_end());
+
+  CurGD = OMD;
+  CurEHLocation = OMD->getEndLoc();
+
+  StartFunction(OMD, OMD->getReturnType(), Fn, FI, args,
+                OMD->getLocation(), StartLoc);
+
+  if (OMD->isDirectMethod()) {
+    // This function is a direct call, it has to implement a nil check
+    // on entry.
+    //
+    // TODO: possibly have several entry points to elide the check
+    CGM.getObjCRuntime().GenerateDirectMethodPrologue(*this, Fn, OMD, CD);
+  }
+
+  // In ARC, certain methods get an extra cleanup.
+  if (CGM.getLangOpts().ObjCAutoRefCount &&
+      OMD->isInstanceMethod() &&
+      OMD->getSelector().isUnarySelector()) {
+    const IdentifierInfo *ident =
+      OMD->getSelector().getIdentifierInfoForSlot(0);
+    if (ident->isStr("dealloc"))
+      EHStack.pushCleanup<FinishARCDealloc>(getARCCleanupKind());
+  }
+}
+
+static llvm::Value *emitARCRetainLoadOfScalar(CodeGenFunction &CGF,
+                                              LValue lvalue, QualType type);
+
+/// Generate an Objective-C method.  An Objective-C method is a C function with
+/// its pointer, name, and types registered in the class structure.
+void CodeGenFunction::GenerateObjCMethod(const ObjCMethodDecl *OMD) {
+  StartObjCMethod(OMD, OMD->getClassInterface());
+  PGO.assignRegionCounters(GlobalDecl(OMD), CurFn);
+  assert(isa<CompoundStmt>(OMD->getBody()));
+  incrementProfileCounter(OMD->getBody());
+  EmitCompoundStmtWithoutScope(*cast<CompoundStmt>(OMD->getBody()));
+  FinishFunction(OMD->getBodyRBrace());
+}
+
+/// emitStructGetterCall - Call the runtime function to load a property
+/// into the return value slot.
+static void emitStructGetterCall(CodeGenFunction &CGF, ObjCIvarDecl *ivar,
+                                 bool isAtomic, bool hasStrong) {
+  ASTContext &Context = CGF.getContext();
+
+  Address src =
+      CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), CGF.LoadObjCSelf(), ivar, 0)
+          .getAddress(CGF);
+
+  // objc_copyStruct (ReturnValue, &structIvar,
+  //                  sizeof (Type of Ivar), isAtomic, false);
+  CallArgList args;
+
+  Address dest = CGF.Builder.CreateBitCast(CGF.ReturnValue, CGF.VoidPtrTy);
+  args.add(RValue::get(dest.getPointer()), Context.VoidPtrTy);
+
+  src = CGF.Builder.CreateBitCast(src, CGF.VoidPtrTy);
+  args.add(RValue::get(src.getPointer()), Context.VoidPtrTy);
+
+  CharUnits size = CGF.getContext().getTypeSizeInChars(ivar->getType());
+  args.add(RValue::get(CGF.CGM.getSize(size)), Context.getSizeType());
+  args.add(RValue::get(CGF.Builder.getInt1(isAtomic)), Context.BoolTy);
+  args.add(RValue::get(CGF.Builder.getInt1(hasStrong)), Context.BoolTy);
+
+  llvm::FunctionCallee fn = CGF.CGM.getObjCRuntime().GetGetStructFunction();
+  CGCallee callee = CGCallee::forDirect(fn);
+  CGF.EmitCall(CGF.getTypes().arrangeBuiltinFunctionCall(Context.VoidTy, args),
+               callee, ReturnValueSlot(), args);
+}
+
+/// Determine whether the given architecture supports unaligned atomic
+/// accesses.  They don't have to be fast, just faster than a function
+/// call and a mutex.
+static bool hasUnalignedAtomics(llvm::Triple::ArchType arch) {
+  // FIXME: Allow unaligned atomic load/store on x86.  (It is not
+  // currently supported by the backend.)
+  return false;
+}
+
+/// Return the maximum size that permits atomic accesses for the given
+/// architecture.
+static CharUnits getMaxAtomicAccessSize(CodeGenModule &CGM,
+                                        llvm::Triple::ArchType arch) {
+  // ARM has 8-byte atomic accesses, but it's not clear whether we
+  // want to rely on them here.
+
+  // In the default case, just assume that any size up to a pointer is
+  // fine given adequate alignment.
+  return CharUnits::fromQuantity(CGM.PointerSizeInBytes);
+}
+
+namespace {
+  class PropertyImplStrategy {
+  public:
+    enum StrategyKind {
+      /// The 'native' strategy is to use the architecture's provided
+      /// reads and writes.
+      Native,
+
+      /// Use objc_setProperty and objc_getProperty.
+      GetSetProperty,
+
+      /// Use objc_setProperty for the setter, but use expression
+      /// evaluation for the getter.
+      SetPropertyAndExpressionGet,
+
+      /// Use objc_copyStruct.
+      CopyStruct,
+
+      /// The 'expression' strategy is to emit normal assignment or
+      /// lvalue-to-rvalue expressions.
+      Expression
+    };
+
+    StrategyKind getKind() const { return StrategyKind(Kind); }
+
+    bool hasStrongMember() const { return HasStrong; }
+    bool isAtomic() const { return IsAtomic; }
+    bool isCopy() const { return IsCopy; }
+
+    CharUnits getIvarSize() const { return IvarSize; }
+    CharUnits getIvarAlignment() const { return IvarAlignment; }
+
+    PropertyImplStrategy(CodeGenModule &CGM,
+                         const ObjCPropertyImplDecl *propImpl);
+
+  private:
+    unsigned Kind : 8;
+    unsigned IsAtomic : 1;
+    unsigned IsCopy : 1;
+    unsigned HasStrong : 1;
+
+    CharUnits IvarSize;
+    CharUnits IvarAlignment;
+  };
+}
+
+/// Pick an implementation strategy for the given property synthesis.
+PropertyImplStrategy::PropertyImplStrategy(CodeGenModule &CGM,
+                                     const ObjCPropertyImplDecl *propImpl) {
+  const ObjCPropertyDecl *prop = propImpl->getPropertyDecl();
+  ObjCPropertyDecl::SetterKind setterKind = prop->getSetterKind();
+
+  IsCopy = (setterKind == ObjCPropertyDecl::Copy);
+  IsAtomic = prop->isAtomic();
+  HasStrong = false; // doesn't matter here.
+
+  // Evaluate the ivar's size and alignment.
+  ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
+  QualType ivarType = ivar->getType();
+  auto TInfo = CGM.getContext().getTypeInfoInChars(ivarType);
+  IvarSize = TInfo.Width;
+  IvarAlignment = TInfo.Align;
+
+  // If we have a copy property, we always have to use setProperty.
+  // If the property is atomic we need to use getProperty, but in
+  // the nonatomic case we can just use expression.
+  if (IsCopy) {
+    Kind = IsAtomic ? GetSetProperty : SetPropertyAndExpressionGet;
+    return;
+  }
+
+  // Handle retain.
+  if (setterKind == ObjCPropertyDecl::Retain) {
+    // In GC-only, there's nothing special that needs to be done.
+    if (CGM.getLangOpts().getGC() == LangOptions::GCOnly) {
+      // fallthrough
+
+    // In ARC, if the property is non-atomic, use expression emission,
+    // which translates to objc_storeStrong.  This isn't required, but
+    // it's slightly nicer.
+    } else if (CGM.getLangOpts().ObjCAutoRefCount && !IsAtomic) {
+      // Using standard expression emission for the setter is only
+      // acceptable if the ivar is __strong, which won't be true if
+      // the property is annotated with __attribute__((NSObject)).
+      // TODO: falling all the way back to objc_setProperty here is
+      // just laziness, though;  we could still use objc_storeStrong
+      // if we hacked it right.
+      if (ivarType.getObjCLifetime() == Qualifiers::OCL_Strong)
+        Kind = Expression;
+      else
+        Kind = SetPropertyAndExpressionGet;
+      return;
+
+    // Otherwise, we need to at least use setProperty.  However, if
+    // the property isn't atomic, we can use normal expression
+    // emission for the getter.
+    } else if (!IsAtomic) {
+      Kind = SetPropertyAndExpressionGet;
+      return;
+
+    // Otherwise, we have to use both setProperty and getProperty.
+    } else {
+      Kind = GetSetProperty;
+      return;
+    }
+  }
+
+  // If we're not atomic, just use expression accesses.
+  if (!IsAtomic) {
+    Kind = Expression;
+    return;
+  }
+
+  // Properties on bitfield ivars need to be emitted using expression
+  // accesses even if they're nominally atomic.
+  if (ivar->isBitField()) {
+    Kind = Expression;
+    return;
+  }
+
+  // GC-qualified or ARC-qualified ivars need to be emitted as
+  // expressions.  This actually works out to being atomic anyway,
+  // except for ARC __strong, but that should trigger the above code.
+  if (ivarType.hasNonTrivialObjCLifetime() ||
+      (CGM.getLangOpts().getGC() &&
+       CGM.getContext().getObjCGCAttrKind(ivarType))) {
+    Kind = Expression;
+    return;
+  }
+
+  // Compute whether the ivar has strong members.
+  if (CGM.getLangOpts().getGC())
+    if (const RecordType *recordType = ivarType->getAs<RecordType>())
+      HasStrong = recordType->getDecl()->hasObjectMember();
+
+  // We can never access structs with object members with a native
+  // access, because we need to use write barriers.  This is what
+  // objc_copyStruct is for.
+  if (HasStrong) {
+    Kind = CopyStruct;
+    return;
+  }
+
+  // Otherwise, this is target-dependent and based on the size and
+  // alignment of the ivar.
+
+  // If the size of the ivar is not a power of two, give up.  We don't
+  // want to get into the business of doing compare-and-swaps.
+  if (!IvarSize.isPowerOfTwo()) {
+    Kind = CopyStruct;
+    return;
+  }
+
+  llvm::Triple::ArchType arch =
+    CGM.getTarget().getTriple().getArch();
+
+  // Most architectures require memory to fit within a single cache
+  // line, so the alignment has to be at least the size of the access.
+  // Otherwise we have to grab a lock.
+  if (IvarAlignment < IvarSize && !hasUnalignedAtomics(arch)) {
+    Kind = CopyStruct;
+    return;
+  }
+
+  // If the ivar's size exceeds the architecture's maximum atomic
+  // access size, we have to use CopyStruct.
+  if (IvarSize > getMaxAtomicAccessSize(CGM, arch)) {
+    Kind = CopyStruct;
+    return;
+  }
+
+  // Otherwise, we can use native loads and stores.
+  Kind = Native;
+}
+
+/// Generate an Objective-C property getter function.
+///
+/// The given Decl must be an ObjCImplementationDecl. \@synthesize
+/// is illegal within a category.
+void CodeGenFunction::GenerateObjCGetter(ObjCImplementationDecl *IMP,
+                                         const ObjCPropertyImplDecl *PID) {
+  llvm::Constant *AtomicHelperFn =
+      CodeGenFunction(CGM).GenerateObjCAtomicGetterCopyHelperFunction(PID);
+  ObjCMethodDecl *OMD = PID->getGetterMethodDecl();
+  assert(OMD && "Invalid call to generate getter (empty method)");
+  StartObjCMethod(OMD, IMP->getClassInterface());
+
+  generateObjCGetterBody(IMP, PID, OMD, AtomicHelperFn);
+
+  FinishFunction(OMD->getEndLoc());
+}
+
+static bool hasTrivialGetExpr(const ObjCPropertyImplDecl *propImpl) {
+  const Expr *getter = propImpl->getGetterCXXConstructor();
+  if (!getter) return true;
+
+  // Sema only makes only of these when the ivar has a C++ class type,
+  // so the form is pretty constrained.
+
+  // If the property has a reference type, we might just be binding a
+  // reference, in which case the result will be a gl-value.  We should
+  // treat this as a non-trivial operation.
+  if (getter->isGLValue())
+    return false;
+
+  // If we selected a trivial copy-constructor, we're okay.
+  if (const CXXConstructExpr *construct = dyn_cast<CXXConstructExpr>(getter))
+    return (construct->getConstructor()->isTrivial());
+
+  // The constructor might require cleanups (in which case it's never
+  // trivial).
+  assert(isa<ExprWithCleanups>(getter));
+  return false;
+}
+
+/// emitCPPObjectAtomicGetterCall - Call the runtime function to
+/// copy the ivar into the resturn slot.
+static void emitCPPObjectAtomicGetterCall(CodeGenFunction &CGF,
+                                          llvm::Value *returnAddr,
+                                          ObjCIvarDecl *ivar,
+                                          llvm::Constant *AtomicHelperFn) {
+  // objc_copyCppObjectAtomic (&returnSlot, &CppObjectIvar,
+  //                           AtomicHelperFn);
+  CallArgList args;
+
+  // The 1st argument is the return Slot.
+  args.add(RValue::get(returnAddr), CGF.getContext().VoidPtrTy);
+
+  // The 2nd argument is the address of the ivar.
+  llvm::Value *ivarAddr =
+      CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), CGF.LoadObjCSelf(), ivar, 0)
+          .getPointer(CGF);
+  ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
+  args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
+
+  // Third argument is the helper function.
+  args.add(RValue::get(AtomicHelperFn), CGF.getContext().VoidPtrTy);
+
+  llvm::FunctionCallee copyCppAtomicObjectFn =
+      CGF.CGM.getObjCRuntime().GetCppAtomicObjectGetFunction();
+  CGCallee callee = CGCallee::forDirect(copyCppAtomicObjectFn);
+  CGF.EmitCall(
+      CGF.getTypes().arrangeBuiltinFunctionCall(CGF.getContext().VoidTy, args),
+               callee, ReturnValueSlot(), args);
+}
+
+void
+CodeGenFunction::generateObjCGetterBody(const ObjCImplementationDecl *classImpl,
+                                        const ObjCPropertyImplDecl *propImpl,
+                                        const ObjCMethodDecl *GetterMethodDecl,
+                                        llvm::Constant *AtomicHelperFn) {
+  // If there's a non-trivial 'get' expression, we just have to emit that.
+  if (!hasTrivialGetExpr(propImpl)) {
+    if (!AtomicHelperFn) {
+      auto *ret = ReturnStmt::Create(getContext(), SourceLocation(),
+                                     propImpl->getGetterCXXConstructor(),
+                                     /* NRVOCandidate=*/nullptr);
+      EmitReturnStmt(*ret);
+    }
+    else {
+      ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
+      emitCPPObjectAtomicGetterCall(*this, ReturnValue.getPointer(),
+                                    ivar, AtomicHelperFn);
+    }
+    return;
+  }
+
+  const ObjCPropertyDecl *prop = propImpl->getPropertyDecl();
+  QualType propType = prop->getType();
+  ObjCMethodDecl *getterMethod = propImpl->getGetterMethodDecl();
+
+  ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
+
+  // Pick an implementation strategy.
+  PropertyImplStrategy strategy(CGM, propImpl);
+  switch (strategy.getKind()) {
+  case PropertyImplStrategy::Native: {
+    // We don't need to do anything for a zero-size struct.
+    if (strategy.getIvarSize().isZero())
+      return;
+
+    LValue LV = EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, 0);
+
+    // Currently, all atomic accesses have to be through integer
+    // types, so there's no point in trying to pick a prettier type.
+    uint64_t ivarSize = getContext().toBits(strategy.getIvarSize());
+    llvm::Type *bitcastType = llvm::Type::getIntNTy(getLLVMContext(), ivarSize);
+    bitcastType = bitcastType->getPointerTo(); // addrspace 0 okay
+
+    // Perform an atomic load.  This does not impose ordering constraints.
+    Address ivarAddr = LV.getAddress(*this);
+    ivarAddr = Builder.CreateBitCast(ivarAddr, bitcastType);
+    llvm::LoadInst *load = Builder.CreateLoad(ivarAddr, "load");
+    load->setAtomic(llvm::AtomicOrdering::Unordered);
+
+    // Store that value into the return address.  Doing this with a
+    // bitcast is likely to produce some pretty ugly IR, but it's not
+    // the *most* terrible thing in the world.
+    llvm::Type *retTy = ConvertType(getterMethod->getReturnType());
+    uint64_t retTySize = CGM.getDataLayout().getTypeSizeInBits(retTy);
+    llvm::Value *ivarVal = load;
+    if (ivarSize > retTySize) {
+      llvm::Type *newTy = llvm::Type::getIntNTy(getLLVMContext(), retTySize);
+      ivarVal = Builder.CreateTrunc(load, newTy);
+      bitcastType = newTy->getPointerTo();
+    }
+    Builder.CreateStore(ivarVal,
+                        Builder.CreateBitCast(ReturnValue, bitcastType));
+
+    // Make sure we don't do an autorelease.
+    AutoreleaseResult = false;
+    return;
+  }
+
+  case PropertyImplStrategy::GetSetProperty: {
+    llvm::FunctionCallee getPropertyFn =
+        CGM.getObjCRuntime().GetPropertyGetFunction();
+    if (!getPropertyFn) {
+      CGM.ErrorUnsupported(propImpl, "Obj-C getter requiring atomic copy");
+      return;
+    }
+    CGCallee callee = CGCallee::forDirect(getPropertyFn);
+
+    // Return (ivar-type) objc_getProperty((id) self, _cmd, offset, true).
+    // FIXME: Can't this be simpler? This might even be worse than the
+    // corresponding gcc code.
+    llvm::Value *cmd =
+      Builder.CreateLoad(GetAddrOfLocalVar(getterMethod->getCmdDecl()), "cmd");
+    llvm::Value *self = Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
+    llvm::Value *ivarOffset =
+      EmitIvarOffset(classImpl->getClassInterface(), ivar);
+
+    CallArgList args;
+    args.add(RValue::get(self), getContext().getObjCIdType());
+    args.add(RValue::get(cmd), getContext().getObjCSelType());
+    args.add(RValue::get(ivarOffset), getContext().getPointerDiffType());
+    args.add(RValue::get(Builder.getInt1(strategy.isAtomic())),
+             getContext().BoolTy);
+
+    // FIXME: We shouldn't need to get the function info here, the
+    // runtime already should have computed it to build the function.
+    llvm::CallBase *CallInstruction;
+    RValue RV = EmitCall(getTypes().arrangeBuiltinFunctionCall(
+                             getContext().getObjCIdType(), args),
+                         callee, ReturnValueSlot(), args, &CallInstruction);
+    if (llvm::CallInst *call = dyn_cast<llvm::CallInst>(CallInstruction))
+      call->setTailCall();
+
+    // We need to fix the type here. Ivars with copy & retain are
+    // always objects so we don't need to worry about complex or
+    // aggregates.
+    RV = RValue::get(Builder.CreateBitCast(
+        RV.getScalarVal(),
+        getTypes().ConvertType(getterMethod->getReturnType())));
+
+    EmitReturnOfRValue(RV, propType);
+
+    // objc_getProperty does an autorelease, so we should suppress ours.
+    AutoreleaseResult = false;
+
+    return;
+  }
+
+  case PropertyImplStrategy::CopyStruct:
+    emitStructGetterCall(*this, ivar, strategy.isAtomic(),
+                         strategy.hasStrongMember());
+    return;
+
+  case PropertyImplStrategy::Expression:
+  case PropertyImplStrategy::SetPropertyAndExpressionGet: {
+    LValue LV = EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, 0);
+
+    QualType ivarType = ivar->getType();
+    switch (getEvaluationKind(ivarType)) {
+    case TEK_Complex: {
+      ComplexPairTy pair = EmitLoadOfComplex(LV, SourceLocation());
+      EmitStoreOfComplex(pair, MakeAddrLValue(ReturnValue, ivarType),
+                         /*init*/ true);
+      return;
+    }
+    case TEK_Aggregate: {
+      // The return value slot is guaranteed to not be aliased, but
+      // that's not necessarily the same as "on the stack", so
+      // we still potentially need objc_memmove_collectable.
+      EmitAggregateCopy(/* Dest= */ MakeAddrLValue(ReturnValue, ivarType),
+                        /* Src= */ LV, ivarType, getOverlapForReturnValue());
+      return;
+    }
+    case TEK_Scalar: {
+      llvm::Value *value;
+      if (propType->isReferenceType()) {
+        value = LV.getAddress(*this).getPointer();
+      } else {
+        // We want to load and autoreleaseReturnValue ARC __weak ivars.
+        if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak) {
+          if (getLangOpts().ObjCAutoRefCount) {
+            value = emitARCRetainLoadOfScalar(*this, LV, ivarType);
+          } else {
+            value = EmitARCLoadWeak(LV.getAddress(*this));
+          }
+
+        // Otherwise we want to do a simple load, suppressing the
+        // final autorelease.
+        } else {
+          value = EmitLoadOfLValue(LV, SourceLocation()).getScalarVal();
+          AutoreleaseResult = false;
+        }
+
+        value = Builder.CreateBitCast(
+            value, ConvertType(GetterMethodDecl->getReturnType()));
+      }
+
+      EmitReturnOfRValue(RValue::get(value), propType);
+      return;
+    }
+    }
+    llvm_unreachable("bad evaluation kind");
+  }
+
+  }
+  llvm_unreachable("bad @property implementation strategy!");
+}
+
+/// emitStructSetterCall - Call the runtime function to store the value
+/// from the first formal parameter into the given ivar.
+static void emitStructSetterCall(CodeGenFunction &CGF, ObjCMethodDecl *OMD,
+                                 ObjCIvarDecl *ivar) {
+  // objc_copyStruct (&structIvar, &Arg,
+  //                  sizeof (struct something), true, false);
+  CallArgList args;
+
+  // The first argument is the address of the ivar.
+  llvm::Value *ivarAddr =
+      CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), CGF.LoadObjCSelf(), ivar, 0)
+          .getPointer(CGF);
+  ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
+  args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
+
+  // The second argument is the address of the parameter variable.
+  ParmVarDecl *argVar = *OMD->param_begin();
+  DeclRefExpr argRef(CGF.getContext(), argVar, false,
+                     argVar->getType().getNonReferenceType(), VK_LValue,
+                     SourceLocation());
+  llvm::Value *argAddr = CGF.EmitLValue(&argRef).getPointer(CGF);
+  argAddr = CGF.Builder.CreateBitCast(argAddr, CGF.Int8PtrTy);
+  args.add(RValue::get(argAddr), CGF.getContext().VoidPtrTy);
+
+  // The third argument is the sizeof the type.
+  llvm::Value *size =
+    CGF.CGM.getSize(CGF.getContext().getTypeSizeInChars(ivar->getType()));
+  args.add(RValue::get(size), CGF.getContext().getSizeType());
+
+  // The fourth argument is the 'isAtomic' flag.
+  args.add(RValue::get(CGF.Builder.getTrue()), CGF.getContext().BoolTy);
+
+  // The fifth argument is the 'hasStrong' flag.
+  // FIXME: should this really always be false?
+  args.add(RValue::get(CGF.Builder.getFalse()), CGF.getContext().BoolTy);
+
+  llvm::FunctionCallee fn = CGF.CGM.getObjCRuntime().GetSetStructFunction();
+  CGCallee callee = CGCallee::forDirect(fn);
+  CGF.EmitCall(
+      CGF.getTypes().arrangeBuiltinFunctionCall(CGF.getContext().VoidTy, args),
+               callee, ReturnValueSlot(), args);
+}
+
+/// emitCPPObjectAtomicSetterCall - Call the runtime function to store
+/// the value from the first formal parameter into the given ivar, using
+/// the Cpp API for atomic Cpp objects with non-trivial copy assignment.
+static void emitCPPObjectAtomicSetterCall(CodeGenFunction &CGF,
+                                          ObjCMethodDecl *OMD,
+                                          ObjCIvarDecl *ivar,
+                                          llvm::Constant *AtomicHelperFn) {
+  // objc_copyCppObjectAtomic (&CppObjectIvar, &Arg,
+  //                           AtomicHelperFn);
+  CallArgList args;
+
+  // The first argument is the address of the ivar.
+  llvm::Value *ivarAddr =
+      CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), CGF.LoadObjCSelf(), ivar, 0)
+          .getPointer(CGF);
+  ivarAddr = CGF.Builder.CreateBitCast(ivarAddr, CGF.Int8PtrTy);
+  args.add(RValue::get(ivarAddr), CGF.getContext().VoidPtrTy);
+
+  // The second argument is the address of the parameter variable.
+  ParmVarDecl *argVar = *OMD->param_begin();
+  DeclRefExpr argRef(CGF.getContext(), argVar, false,
+                     argVar->getType().getNonReferenceType(), VK_LValue,
+                     SourceLocation());
+  llvm::Value *argAddr = CGF.EmitLValue(&argRef).getPointer(CGF);
+  argAddr = CGF.Builder.CreateBitCast(argAddr, CGF.Int8PtrTy);
+  args.add(RValue::get(argAddr), CGF.getContext().VoidPtrTy);
+
+  // Third argument is the helper function.
+  args.add(RValue::get(AtomicHelperFn), CGF.getContext().VoidPtrTy);
+
+  llvm::FunctionCallee fn =
+      CGF.CGM.getObjCRuntime().GetCppAtomicObjectSetFunction();
+  CGCallee callee = CGCallee::forDirect(fn);
+  CGF.EmitCall(
+      CGF.getTypes().arrangeBuiltinFunctionCall(CGF.getContext().VoidTy, args),
+               callee, ReturnValueSlot(), args);
+}
+
+
+static bool hasTrivialSetExpr(const ObjCPropertyImplDecl *PID) {
+  Expr *setter = PID->getSetterCXXAssignment();
+  if (!setter) return true;
+
+  // Sema only makes only of these when the ivar has a C++ class type,
+  // so the form is pretty constrained.
+
+  // An operator call is trivial if the function it calls is trivial.
+  // This also implies that there's nothing non-trivial going on with
+  // the arguments, because operator= can only be trivial if it's a
+  // synthesized assignment operator and therefore both parameters are
+  // references.
+  if (CallExpr *call = dyn_cast<CallExpr>(setter)) {
+    if (const FunctionDecl *callee
+          = dyn_cast_or_null<FunctionDecl>(call->getCalleeDecl()))
+      if (callee->isTrivial())
+        return true;
+    return false;
+  }
+
+  assert(isa<ExprWithCleanups>(setter));
+  return false;
+}
+
+static bool UseOptimizedSetter(CodeGenModule &CGM) {
+  if (CGM.getLangOpts().getGC() != LangOptions::NonGC)
+    return false;
+  return CGM.getLangOpts().ObjCRuntime.hasOptimizedSetter();
+}
+
+void
+CodeGenFunction::generateObjCSetterBody(const ObjCImplementationDecl *classImpl,
+                                        const ObjCPropertyImplDecl *propImpl,
+                                        llvm::Constant *AtomicHelperFn) {
+  ObjCIvarDecl *ivar = propImpl->getPropertyIvarDecl();
+  ObjCMethodDecl *setterMethod = propImpl->getSetterMethodDecl();
+
+  // Just use the setter expression if Sema gave us one and it's
+  // non-trivial.
+  if (!hasTrivialSetExpr(propImpl)) {
+    if (!AtomicHelperFn)
+      // If non-atomic, assignment is called directly.
+      EmitStmt(propImpl->getSetterCXXAssignment());
+    else
+      // If atomic, assignment is called via a locking api.
+      emitCPPObjectAtomicSetterCall(*this, setterMethod, ivar,
+                                    AtomicHelperFn);
+    return;
+  }
+
+  PropertyImplStrategy strategy(CGM, propImpl);
+  switch (strategy.getKind()) {
+  case PropertyImplStrategy::Native: {
+    // We don't need to do anything for a zero-size struct.
+    if (strategy.getIvarSize().isZero())
+      return;
+
+    Address argAddr = GetAddrOfLocalVar(*setterMethod->param_begin());
+
+    LValue ivarLValue =
+      EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, /*quals*/ 0);
+    Address ivarAddr = ivarLValue.getAddress(*this);
+
+    // Currently, all atomic accesses have to be through integer
+    // types, so there's no point in trying to pick a prettier type.
+    llvm::Type *bitcastType =
+      llvm::Type::getIntNTy(getLLVMContext(),
+                            getContext().toBits(strategy.getIvarSize()));
+
+    // Cast both arguments to the chosen operation type.
+    argAddr = Builder.CreateElementBitCast(argAddr, bitcastType);
+    ivarAddr = Builder.CreateElementBitCast(ivarAddr, bitcastType);
+
+    // This bitcast load is likely to cause some nasty IR.
+    llvm::Value *load = Builder.CreateLoad(argAddr);
+
+    // Perform an atomic store.  There are no memory ordering requirements.
+    llvm::StoreInst *store = Builder.CreateStore(load, ivarAddr);
+    store->setAtomic(llvm::AtomicOrdering::Unordered);
+    return;
+  }
+
+  case PropertyImplStrategy::GetSetProperty:
+  case PropertyImplStrategy::SetPropertyAndExpressionGet: {
+
+    llvm::FunctionCallee setOptimizedPropertyFn = nullptr;
+    llvm::FunctionCallee setPropertyFn = nullptr;
+    if (UseOptimizedSetter(CGM)) {
+      // 10.8 and iOS 6.0 code and GC is off
+      setOptimizedPropertyFn =
+          CGM.getObjCRuntime().GetOptimizedPropertySetFunction(
+              strategy.isAtomic(), strategy.isCopy());
+      if (!setOptimizedPropertyFn) {
+        CGM.ErrorUnsupported(propImpl, "Obj-C optimized setter - NYI");
+        return;
+      }
+    }
+    else {
+      setPropertyFn = CGM.getObjCRuntime().GetPropertySetFunction();
+      if (!setPropertyFn) {
+        CGM.ErrorUnsupported(propImpl, "Obj-C setter requiring atomic copy");
+        return;
+      }
+    }
+
+    // Emit objc_setProperty((id) self, _cmd, offset, arg,
+    //                       <is-atomic>, <is-copy>).
+    llvm::Value *cmd =
+      Builder.CreateLoad(GetAddrOfLocalVar(setterMethod->getCmdDecl()));
+    llvm::Value *self =
+      Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
+    llvm::Value *ivarOffset =
+      EmitIvarOffset(classImpl->getClassInterface(), ivar);
+    Address argAddr = GetAddrOfLocalVar(*setterMethod->param_begin());
+    llvm::Value *arg = Builder.CreateLoad(argAddr, "arg");
+    arg = Builder.CreateBitCast(arg, VoidPtrTy);
+
+    CallArgList args;
+    args.add(RValue::get(self), getContext().getObjCIdType());
+    args.add(RValue::get(cmd), getContext().getObjCSelType());
+    if (setOptimizedPropertyFn) {
+      args.add(RValue::get(arg), getContext().getObjCIdType());
+      args.add(RValue::get(ivarOffset), getContext().getPointerDiffType());
+      CGCallee callee = CGCallee::forDirect(setOptimizedPropertyFn);
+      EmitCall(getTypes().arrangeBuiltinFunctionCall(getContext().VoidTy, args),
+               callee, ReturnValueSlot(), args);
+    } else {
+      args.add(RValue::get(ivarOffset), getContext().getPointerDiffType());
+      args.add(RValue::get(arg), getContext().getObjCIdType());
+      args.add(RValue::get(Builder.getInt1(strategy.isAtomic())),
+               getContext().BoolTy);
+      args.add(RValue::get(Builder.getInt1(strategy.isCopy())),
+               getContext().BoolTy);
+      // FIXME: We shouldn't need to get the function info here, the runtime
+      // already should have computed it to build the function.
+      CGCallee callee = CGCallee::forDirect(setPropertyFn);
+      EmitCall(getTypes().arrangeBuiltinFunctionCall(getContext().VoidTy, args),
+               callee, ReturnValueSlot(), args);
+    }
+
+    return;
+  }
+
+  case PropertyImplStrategy::CopyStruct:
+    emitStructSetterCall(*this, setterMethod, ivar);
+    return;
+
+  case PropertyImplStrategy::Expression:
+    break;
+  }
+
+  // Otherwise, fake up some ASTs and emit a normal assignment.
+  ValueDecl *selfDecl = setterMethod->getSelfDecl();
+  DeclRefExpr self(getContext(), selfDecl, false, selfDecl->getType(),
+                   VK_LValue, SourceLocation());
+  ImplicitCastExpr selfLoad(ImplicitCastExpr::OnStack, selfDecl->getType(),
+                            CK_LValueToRValue, &self, VK_PRValue,
+                            FPOptionsOverride());
+  ObjCIvarRefExpr ivarRef(ivar, ivar->getType().getNonReferenceType(),
+                          SourceLocation(), SourceLocation(),
+                          &selfLoad, true, true);
+
+  ParmVarDecl *argDecl = *setterMethod->param_begin();
+  QualType argType = argDecl->getType().getNonReferenceType();
+  DeclRefExpr arg(getContext(), argDecl, false, argType, VK_LValue,
+                  SourceLocation());
+  ImplicitCastExpr argLoad(ImplicitCastExpr::OnStack,
+                           argType.getUnqualifiedType(), CK_LValueToRValue,
+                           &arg, VK_PRValue, FPOptionsOverride());
+
+  // The property type can differ from the ivar type in some situations with
+  // Objective-C pointer types, we can always bit cast the RHS in these cases.
+  // The following absurdity is just to ensure well-formed IR.
+  CastKind argCK = CK_NoOp;
+  if (ivarRef.getType()->isObjCObjectPointerType()) {
+    if (argLoad.getType()->isObjCObjectPointerType())
+      argCK = CK_BitCast;
+    else if (argLoad.getType()->isBlockPointerType())
+      argCK = CK_BlockPointerToObjCPointerCast;
+    else
+      argCK = CK_CPointerToObjCPointerCast;
+  } else if (ivarRef.getType()->isBlockPointerType()) {
+     if (argLoad.getType()->isBlockPointerType())
+      argCK = CK_BitCast;
+    else
+      argCK = CK_AnyPointerToBlockPointerCast;
+  } else if (ivarRef.getType()->isPointerType()) {
+    argCK = CK_BitCast;
+  } else if (argLoad.getType()->isAtomicType() &&
+             !ivarRef.getType()->isAtomicType()) {
+    argCK = CK_AtomicToNonAtomic;
+  } else if (!argLoad.getType()->isAtomicType() &&
+             ivarRef.getType()->isAtomicType()) {
+    argCK = CK_NonAtomicToAtomic;
+  }
+  ImplicitCastExpr argCast(ImplicitCastExpr::OnStack, ivarRef.getType(), argCK,
+                           &argLoad, VK_PRValue, FPOptionsOverride());
+  Expr *finalArg = &argLoad;
+  if (!getContext().hasSameUnqualifiedType(ivarRef.getType(),
+                                           argLoad.getType()))
+    finalArg = &argCast;
+
+  BinaryOperator *assign = BinaryOperator::Create(
+      getContext(), &ivarRef, finalArg, BO_Assign, ivarRef.getType(),
+      VK_PRValue, OK_Ordinary, SourceLocation(), FPOptionsOverride());
+  EmitStmt(assign);
+}
+
+/// Generate an Objective-C property setter function.
+///
+/// The given Decl must be an ObjCImplementationDecl. \@synthesize
+/// is illegal within a category.
+void CodeGenFunction::GenerateObjCSetter(ObjCImplementationDecl *IMP,
+                                         const ObjCPropertyImplDecl *PID) {
+  llvm::Constant *AtomicHelperFn =
+      CodeGenFunction(CGM).GenerateObjCAtomicSetterCopyHelperFunction(PID);
+  ObjCMethodDecl *OMD = PID->getSetterMethodDecl();
+  assert(OMD && "Invalid call to generate setter (empty method)");
+  StartObjCMethod(OMD, IMP->getClassInterface());
+
+  generateObjCSetterBody(IMP, PID, AtomicHelperFn);
+
+  FinishFunction(OMD->getEndLoc());
+}
+
+namespace {
+  struct DestroyIvar final : EHScopeStack::Cleanup {
+  private:
+    llvm::Value *addr;
+    const ObjCIvarDecl *ivar;
+    CodeGenFunction::Destroyer *destroyer;
+    bool useEHCleanupForArray;
+  public:
+    DestroyIvar(llvm::Value *addr, const ObjCIvarDecl *ivar,
+                CodeGenFunction::Destroyer *destroyer,
+                bool useEHCleanupForArray)
+      : addr(addr), ivar(ivar), destroyer(destroyer),
+        useEHCleanupForArray(useEHCleanupForArray) {}
+
+    void Emit(CodeGenFunction &CGF, Flags flags) override {
+      LValue lvalue
+        = CGF.EmitLValueForIvar(CGF.TypeOfSelfObject(), addr, ivar, /*CVR*/ 0);
+      CGF.emitDestroy(lvalue.getAddress(CGF), ivar->getType(), destroyer,
+                      flags.isForNormalCleanup() && useEHCleanupForArray);
+    }
+  };
+}
+
+/// Like CodeGenFunction::destroyARCStrong, but do it with a call.
+static void destroyARCStrongWithStore(CodeGenFunction &CGF,
+                                      Address addr,
+                                      QualType type) {
+  llvm::Value *null = getNullForVariable(addr);
+  CGF.EmitARCStoreStrongCall(addr, null, /*ignored*/ true);
+}
+
+static void emitCXXDestructMethod(CodeGenFunction &CGF,
+                                  ObjCImplementationDecl *impl) {
+  CodeGenFunction::RunCleanupsScope scope(CGF);
+
+  llvm::Value *self = CGF.LoadObjCSelf();
+
+  const ObjCInterfaceDecl *iface = impl->getClassInterface();
+  for (const ObjCIvarDecl *ivar = iface->all_declared_ivar_begin();
+       ivar; ivar = ivar->getNextIvar()) {
+    QualType type = ivar->getType();
+
+    // Check whether the ivar is a destructible type.
+    QualType::DestructionKind dtorKind = type.isDestructedType();
+    if (!dtorKind) continue;
+
+    CodeGenFunction::Destroyer *destroyer = nullptr;
+
+    // Use a call to objc_storeStrong to destroy strong ivars, for the
+    // general benefit of the tools.
+    if (dtorKind == QualType::DK_objc_strong_lifetime) {
+      destroyer = destroyARCStrongWithStore;
+
+    // Otherwise use the default for the destruction kind.
+    } else {
+      destroyer = CGF.getDestroyer(dtorKind);
+    }
+
+    CleanupKind cleanupKind = CGF.getCleanupKind(dtorKind);
+
+    CGF.EHStack.pushCleanup<DestroyIvar>(cleanupKind, self, ivar, destroyer,
+                                         cleanupKind & EHCleanup);
+  }
+
+  assert(scope.requiresCleanups() && "nothing to do in .cxx_destruct?");
+}
+
+void CodeGenFunction::GenerateObjCCtorDtorMethod(ObjCImplementationDecl *IMP,
+                                                 ObjCMethodDecl *MD,
+                                                 bool ctor) {
+  MD->createImplicitParams(CGM.getContext(), IMP->getClassInterface());
+  StartObjCMethod(MD, IMP->getClassInterface());
+
+  // Emit .cxx_construct.
+  if (ctor) {
+    // Suppress the final autorelease in ARC.
+    AutoreleaseResult = false;
+
+    for (const auto *IvarInit : IMP->inits()) {
+      FieldDecl *Field = IvarInit->getAnyMember();
+      ObjCIvarDecl *Ivar = cast<ObjCIvarDecl>(Field);
+      LValue LV = EmitLValueForIvar(TypeOfSelfObject(),
+                                    LoadObjCSelf(), Ivar, 0);
+      EmitAggExpr(IvarInit->getInit(),
+                  AggValueSlot::forLValue(LV, *this, AggValueSlot::IsDestructed,
+                                          AggValueSlot::DoesNotNeedGCBarriers,
+                                          AggValueSlot::IsNotAliased,
+                                          AggValueSlot::DoesNotOverlap));
+    }
+    // constructor returns 'self'.
+    CodeGenTypes &Types = CGM.getTypes();
+    QualType IdTy(CGM.getContext().getObjCIdType());
+    llvm::Value *SelfAsId =
+      Builder.CreateBitCast(LoadObjCSelf(), Types.ConvertType(IdTy));
+    EmitReturnOfRValue(RValue::get(SelfAsId), IdTy);
+
+  // Emit .cxx_destruct.
+  } else {
+    emitCXXDestructMethod(*this, IMP);
+  }
+  FinishFunction();
+}
+
+llvm::Value *CodeGenFunction::LoadObjCSelf() {
+  VarDecl *Self = cast<ObjCMethodDecl>(CurFuncDecl)->getSelfDecl();
+  DeclRefExpr DRE(getContext(), Self,
+                  /*is enclosing local*/ (CurFuncDecl != CurCodeDecl),
+                  Self->getType(), VK_LValue, SourceLocation());
+  return EmitLoadOfScalar(EmitDeclRefLValue(&DRE), SourceLocation());
+}
+
+QualType CodeGenFunction::TypeOfSelfObject() {
+  const ObjCMethodDecl *OMD = cast<ObjCMethodDecl>(CurFuncDecl);
+  ImplicitParamDecl *selfDecl = OMD->getSelfDecl();
+  const ObjCObjectPointerType *PTy = cast<ObjCObjectPointerType>(
+    getContext().getCanonicalType(selfDecl->getType()));
+  return PTy->getPointeeType();
+}
+
+void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
+  llvm::FunctionCallee EnumerationMutationFnPtr =
+      CGM.getObjCRuntime().EnumerationMutationFunction();
+  if (!EnumerationMutationFnPtr) {
+    CGM.ErrorUnsupported(&S, "Obj-C fast enumeration for this runtime");
+    return;
+  }
+  CGCallee EnumerationMutationFn =
+    CGCallee::forDirect(EnumerationMutationFnPtr);
+
+  CGDebugInfo *DI = getDebugInfo();
+  if (DI)
+    DI->EmitLexicalBlockStart(Builder, S.getSourceRange().getBegin());
+
+  RunCleanupsScope ForScope(*this);
+
+  // The local variable comes into scope immediately.
+  AutoVarEmission variable = AutoVarEmission::invalid();
+  if (const DeclStmt *SD = dyn_cast<DeclStmt>(S.getElement()))
+    variable = EmitAutoVarAlloca(*cast<VarDecl>(SD->getSingleDecl()));
+
+  JumpDest LoopEnd = getJumpDestInCurrentScope("forcoll.end");
+
+  // Fast enumeration state.
+  QualType StateTy = CGM.getObjCFastEnumerationStateType();
+  Address StatePtr = CreateMemTemp(StateTy, "state.ptr");
+  EmitNullInitialization(StatePtr, StateTy);
+
+  // Number of elements in the items array.
+  static const unsigned NumItems = 16;
+
+  // Fetch the countByEnumeratingWithState:objects:count: selector.
+  IdentifierInfo *II[] = {
+    &CGM.getContext().Idents.get("countByEnumeratingWithState"),
+    &CGM.getContext().Idents.get("objects"),
+    &CGM.getContext().Idents.get("count")
+  };
+  Selector FastEnumSel =
+    CGM.getContext().Selectors.getSelector(llvm::array_lengthof(II), &II[0]);
+
+  QualType ItemsTy =
+    getContext().getConstantArrayType(getContext().getObjCIdType(),
+                                      llvm::APInt(32, NumItems), nullptr,
+                                      ArrayType::Normal, 0);
+  Address ItemsPtr = CreateMemTemp(ItemsTy, "items.ptr");
+
+  // Emit the collection pointer.  In ARC, we do a retain.
+  llvm::Value *Collection;
+  if (getLangOpts().ObjCAutoRefCount) {
+    Collection = EmitARCRetainScalarExpr(S.getCollection());
+
+    // Enter a cleanup to do the release.
+    EmitObjCConsumeObject(S.getCollection()->getType(), Collection);
+  } else {
+    Collection = EmitScalarExpr(S.getCollection());
+  }
+
+  // The 'continue' label needs to appear within the cleanup for the
+  // collection object.
+  JumpDest AfterBody = getJumpDestInCurrentScope("forcoll.next");
+
+  // Send it our message:
+  CallArgList Args;
+
+  // The first argument is a temporary of the enumeration-state type.
+  Args.add(RValue::get(StatePtr.getPointer()),
+           getContext().getPointerType(StateTy));
+
+  // The second argument is a temporary array with space for NumItems
+  // pointers.  We'll actually be loading elements from the array
+  // pointer written into the control state; this buffer is so that
+  // collections that *aren't* backed by arrays can still queue up
+  // batches of elements.
+  Args.add(RValue::get(ItemsPtr.getPointer()),
+           getContext().getPointerType(ItemsTy));
+
+  // The third argument is the capacity of that temporary array.
+  llvm::Type *NSUIntegerTy = ConvertType(getContext().getNSUIntegerType());
+  llvm::Constant *Count = llvm::ConstantInt::get(NSUIntegerTy, NumItems);
+  Args.add(RValue::get(Count), getContext().getNSUIntegerType());
+
+  // Start the enumeration.
+  RValue CountRV =
+      CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
+                                               getContext().getNSUIntegerType(),
+                                               FastEnumSel, Collection, Args);
+
+  // The initial number of objects that were returned in the buffer.
+  llvm::Value *initialBufferLimit = CountRV.getScalarVal();
+
+  llvm::BasicBlock *EmptyBB = createBasicBlock("forcoll.empty");
+  llvm::BasicBlock *LoopInitBB = createBasicBlock("forcoll.loopinit");
+
+  llvm::Value *zero = llvm::Constant::getNullValue(NSUIntegerTy);
+
+  // If the limit pointer was zero to begin with, the collection is
+  // empty; skip all this. Set the branch weight assuming this has the same
+  // probability of exiting the loop as any other loop exit.
+  uint64_t EntryCount = getCurrentProfileCount();
+  Builder.CreateCondBr(
+      Builder.CreateICmpEQ(initialBufferLimit, zero, "iszero"), EmptyBB,
+      LoopInitBB,
+      createProfileWeights(EntryCount, getProfileCount(S.getBody())));
+
+  // Otherwise, initialize the loop.
+  EmitBlock(LoopInitBB);
+
+  // Save the initial mutations value.  This is the value at an
+  // address that was written into the state object by
+  // countByEnumeratingWithState:objects:count:.
+  Address StateMutationsPtrPtr =
+      Builder.CreateStructGEP(StatePtr, 2, "mutationsptr.ptr");
+  llvm::Value *StateMutationsPtr
+    = Builder.CreateLoad(StateMutationsPtrPtr, "mutationsptr");
+
+  llvm::Type *UnsignedLongTy = ConvertType(getContext().UnsignedLongTy);
+  llvm::Value *initialMutations =
+    Builder.CreateAlignedLoad(UnsignedLongTy, StateMutationsPtr,
+                              getPointerAlign(), "forcoll.initial-mutations");
+
+  // Start looping.  This is the point we return to whenever we have a
+  // fresh, non-empty batch of objects.
+  llvm::BasicBlock *LoopBodyBB = createBasicBlock("forcoll.loopbody");
+  EmitBlock(LoopBodyBB);
+
+  // The current index into the buffer.
+  llvm::PHINode *index = Builder.CreatePHI(NSUIntegerTy, 3, "forcoll.index");
+  index->addIncoming(zero, LoopInitBB);
+
+  // The current buffer size.
+  llvm::PHINode *count = Builder.CreatePHI(NSUIntegerTy, 3, "forcoll.count");
+  count->addIncoming(initialBufferLimit, LoopInitBB);
+
+  incrementProfileCounter(&S);
+
+  // Check whether the mutations value has changed from where it was
+  // at start.  StateMutationsPtr should actually be invariant between
+  // refreshes.
+  StateMutationsPtr = Builder.CreateLoad(StateMutationsPtrPtr, "mutationsptr");
+  llvm::Value *currentMutations
+    = Builder.CreateAlignedLoad(UnsignedLongTy, StateMutationsPtr,
+                                getPointerAlign(), "statemutations");
+
+  llvm::BasicBlock *WasMutatedBB = createBasicBlock("forcoll.mutated");
+  llvm::BasicBlock *WasNotMutatedBB = createBasicBlock("forcoll.notmutated");
+
+  Builder.CreateCondBr(Builder.CreateICmpEQ(currentMutations, initialMutations),
+                       WasNotMutatedBB, WasMutatedBB);
+
+  // If so, call the enumeration-mutation function.
+  EmitBlock(WasMutatedBB);
+  llvm::Type *ObjCIdType = ConvertType(getContext().getObjCIdType());
+  llvm::Value *V =
+    Builder.CreateBitCast(Collection, ObjCIdType);
+  CallArgList Args2;
+  Args2.add(RValue::get(V), getContext().getObjCIdType());
+  // FIXME: We shouldn't need to get the function info here, the runtime already
+  // should have computed it to build the function.
+  EmitCall(
+          CGM.getTypes().arrangeBuiltinFunctionCall(getContext().VoidTy, Args2),
+           EnumerationMutationFn, ReturnValueSlot(), Args2);
+
+  // Otherwise, or if the mutation function returns, just continue.
+  EmitBlock(WasNotMutatedBB);
+
+  // Initialize the element variable.
+  RunCleanupsScope elementVariableScope(*this);
+  bool elementIsVariable;
+  LValue elementLValue;
+  QualType elementType;
+  if (const DeclStmt *SD = dyn_cast<DeclStmt>(S.getElement())) {
+    // Initialize the variable, in case it's a __block variable or something.
+    EmitAutoVarInit(variable);
+
+    const VarDecl *D = cast<VarDecl>(SD->getSingleDecl());
+    DeclRefExpr tempDRE(getContext(), const_cast<VarDecl *>(D), false,
+                        D->getType(), VK_LValue, SourceLocation());
+    elementLValue = EmitLValue(&tempDRE);
+    elementType = D->getType();
+    elementIsVariable = true;
+
+    if (D->isARCPseudoStrong())
+      elementLValue.getQuals().setObjCLifetime(Qualifiers::OCL_ExplicitNone);
+  } else {
+    elementLValue = LValue(); // suppress warning
+    elementType = cast<Expr>(S.getElement())->getType();
+    elementIsVariable = false;
+  }
+  llvm::Type *convertedElementType = ConvertType(elementType);
+
+  // Fetch the buffer out of the enumeration state.
+  // TODO: this pointer should actually be invariant between
+  // refreshes, which would help us do certain loop optimizations.
+  Address StateItemsPtr =
+      Builder.CreateStructGEP(StatePtr, 1, "stateitems.ptr");
+  llvm::Value *EnumStateItems =
+    Builder.CreateLoad(StateItemsPtr, "stateitems");
+
+  // Fetch the value at the current index from the buffer.
+  llvm::Value *CurrentItemPtr = Builder.CreateGEP(
+      EnumStateItems->getType()->getPointerElementType(), EnumStateItems, index,
+      "currentitem.ptr");
+  llvm::Value *CurrentItem =
+    Builder.CreateAlignedLoad(ObjCIdType, CurrentItemPtr, getPointerAlign());
+
+  if (SanOpts.has(SanitizerKind::ObjCCast)) {
+    // Before using an item from the collection, check that the implicit cast
+    // from id to the element type is valid. This is done with instrumentation
+    // roughly corresponding to:
+    //
+    //   if (![item isKindOfClass:expectedCls]) { /* emit diagnostic */ }
+    const ObjCObjectPointerType *ObjPtrTy =
+        elementType->getAsObjCInterfacePointerType();
+    const ObjCInterfaceType *InterfaceTy =
+        ObjPtrTy ? ObjPtrTy->getInterfaceType() : nullptr;
+    if (InterfaceTy) {
+      SanitizerScope SanScope(this);
+      auto &C = CGM.getContext();
+      assert(InterfaceTy->getDecl() && "No decl for ObjC interface type");
+      Selector IsKindOfClassSel = GetUnarySelector("isKindOfClass", C);
+      CallArgList IsKindOfClassArgs;
+      llvm::Value *Cls =
+          CGM.getObjCRuntime().GetClass(*this, InterfaceTy->getDecl());
+      IsKindOfClassArgs.add(RValue::get(Cls), C.getObjCClassType());
+      llvm::Value *IsClass =
+          CGM.getObjCRuntime()
+              .GenerateMessageSend(*this, ReturnValueSlot(), C.BoolTy,
+                                   IsKindOfClassSel, CurrentItem,
+                                   IsKindOfClassArgs)
+              .getScalarVal();
+      llvm::Constant *StaticData[] = {
+          EmitCheckSourceLocation(S.getBeginLoc()),
+          EmitCheckTypeDescriptor(QualType(InterfaceTy, 0))};
+      EmitCheck({{IsClass, SanitizerKind::ObjCCast}},
+                SanitizerHandler::InvalidObjCCast,
+                ArrayRef<llvm::Constant *>(StaticData), CurrentItem);
+    }
+  }
+
+  // Cast that value to the right type.
+  CurrentItem = Builder.CreateBitCast(CurrentItem, convertedElementType,
+                                      "currentitem");
+
+  // Make sure we have an l-value.  Yes, this gets evaluated every
+  // time through the loop.
+  if (!elementIsVariable) {
+    elementLValue = EmitLValue(cast<Expr>(S.getElement()));
+    EmitStoreThroughLValue(RValue::get(CurrentItem), elementLValue);
+  } else {
+    EmitStoreThroughLValue(RValue::get(CurrentItem), elementLValue,
+                           /*isInit*/ true);
+  }
+
+  // If we do have an element variable, this assignment is the end of
+  // its initialization.
+  if (elementIsVariable)
+    EmitAutoVarCleanups(variable);
+
+  // Perform the loop body, setting up break and continue labels.
+  BreakContinueStack.push_back(BreakContinue(LoopEnd, AfterBody));
+  {
+    RunCleanupsScope Scope(*this);
+    EmitStmt(S.getBody());
+  }
+  BreakContinueStack.pop_back();
+
+  // Destroy the element variable now.
+  elementVariableScope.ForceCleanup();
+
+  // Check whether there are more elements.
+  EmitBlock(AfterBody.getBlock());
+
+  llvm::BasicBlock *FetchMoreBB = createBasicBlock("forcoll.refetch");
+
+  // First we check in the local buffer.
+  llvm::Value *indexPlusOne =
+      Builder.CreateAdd(index, llvm::ConstantInt::get(NSUIntegerTy, 1));
+
+  // If we haven't overrun the buffer yet, we can continue.
+  // Set the branch weights based on the simplifying assumption that this is
+  // like a while-loop, i.e., ignoring that the false branch fetches more
+  // elements and then returns to the loop.
+  Builder.CreateCondBr(
+      Builder.CreateICmpULT(indexPlusOne, count), LoopBodyBB, FetchMoreBB,
+      createProfileWeights(getProfileCount(S.getBody()), EntryCount));
+
+  index->addIncoming(indexPlusOne, AfterBody.getBlock());
+  count->addIncoming(count, AfterBody.getBlock());
+
+  // Otherwise, we have to fetch more elements.
+  EmitBlock(FetchMoreBB);
+
+  CountRV =
+      CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
+                                               getContext().getNSUIntegerType(),
+                                               FastEnumSel, Collection, Args);
+
+  // If we got a zero count, we're done.
+  llvm::Value *refetchCount = CountRV.getScalarVal();
+
+  // (note that the message send might split FetchMoreBB)
+  index->addIncoming(zero, Builder.GetInsertBlock());
+  count->addIncoming(refetchCount, Builder.GetInsertBlock());
+
+  Builder.CreateCondBr(Builder.CreateICmpEQ(refetchCount, zero),
+                       EmptyBB, LoopBodyBB);
+
+  // No more elements.
+  EmitBlock(EmptyBB);
+
+  if (!elementIsVariable) {
+    // If the element was not a declaration, set it to be null.
+
+    llvm::Value *null = llvm::Constant::getNullValue(convertedElementType);
+    elementLValue = EmitLValue(cast<Expr>(S.getElement()));
+    EmitStoreThroughLValue(RValue::get(null), elementLValue);
+  }
+
+  if (DI)
+    DI->EmitLexicalBlockEnd(Builder, S.getSourceRange().getEnd());
+
+  ForScope.ForceCleanup();
+  EmitBlock(LoopEnd.getBlock());
+}
+
+void CodeGenFunction::EmitObjCAtTryStmt(const ObjCAtTryStmt &S) {
+  CGM.getObjCRuntime().EmitTryStmt(*this, S);
+}
+
+void CodeGenFunction::EmitObjCAtThrowStmt(const ObjCAtThrowStmt &S) {
+  CGM.getObjCRuntime().EmitThrowStmt(*this, S);
+}
+
+void CodeGenFunction::EmitObjCAtSynchronizedStmt(
+                                              const ObjCAtSynchronizedStmt &S) {
+  CGM.getObjCRuntime().EmitSynchronizedStmt(*this, S);
+}
+
+namespace {
+  struct CallObjCRelease final : EHScopeStack::Cleanup {
+    CallObjCRelease(llvm::Value *object) : object(object) {}
+    llvm::Value *object;
+
+    void Emit(CodeGenFunction &CGF, Flags flags) override {
+      // Releases at the end of the full-expression are imprecise.
+      CGF.EmitARCRelease(object, ARCImpreciseLifetime);
+    }
+  };
+}
+
+/// Produce the code for a CK_ARCConsumeObject.  Does a primitive
+/// release at the end of the full-expression.
+llvm::Value *CodeGenFunction::EmitObjCConsumeObject(QualType type,
+                                                    llvm::Value *object) {
+  // If we're in a conditional branch, we need to make the cleanup
+  // conditional.
+  pushFullExprCleanup<CallObjCRelease>(getARCCleanupKind(), object);
+  return object;
+}
+
+llvm::Value *CodeGenFunction::EmitObjCExtendObjectLifetime(QualType type,
+                                                           llvm::Value *value) {
+  return EmitARCRetainAutorelease(type, value);
+}
+
+/// Given a number of pointers, inform the optimizer that they're
+/// being intrinsically used up until this point in the program.
+void CodeGenFunction::EmitARCIntrinsicUse(ArrayRef<llvm::Value*> values) {
+  llvm::Function *&fn = CGM.getObjCEntrypoints().clang_arc_use;
+  if (!fn)
+    fn = CGM.getIntrinsic(llvm::Intrinsic::objc_clang_arc_use);
+
+  // This isn't really a "runtime" function, but as an intrinsic it
+  // doesn't really matter as long as we align things up.
+  EmitNounwindRuntimeCall(fn, values);
+}
+
+/// Emit a call to "clang.arc.noop.use", which consumes the result of a call
+/// that has operand bundle "clang.arc.attachedcall".
+void CodeGenFunction::EmitARCNoopIntrinsicUse(ArrayRef<llvm::Value *> values) {
+  llvm::Function *&fn = CGM.getObjCEntrypoints().clang_arc_noop_use;
+  if (!fn)
+    fn = CGM.getIntrinsic(llvm::Intrinsic::objc_clang_arc_noop_use);
+  EmitNounwindRuntimeCall(fn, values);
+}
+
+static void setARCRuntimeFunctionLinkage(CodeGenModule &CGM, llvm::Value *RTF) {
+  if (auto *F = dyn_cast<llvm::Function>(RTF)) {
+    // If the target runtime doesn't naturally support ARC, emit weak
+    // references to the runtime support library.  We don't really
+    // permit this to fail, but we need a particular relocation style.
+    if (!CGM.getLangOpts().ObjCRuntime.hasNativeARC() &&
+        !CGM.getTriple().isOSBinFormatCOFF()) {
+      F->setLinkage(llvm::Function::ExternalWeakLinkage);
+    }
+  }
+}
+
+static void setARCRuntimeFunctionLinkage(CodeGenModule &CGM,
+                                         llvm::FunctionCallee RTF) {
+  setARCRuntimeFunctionLinkage(CGM, RTF.getCallee());
+}
+
+static llvm::Function *getARCIntrinsic(llvm::Intrinsic::ID IntID,
+                                       CodeGenModule &CGM) {
+  llvm::Function *fn = CGM.getIntrinsic(IntID);
+  setARCRuntimeFunctionLinkage(CGM, fn);
+  return fn;
+}
+
+/// Perform an operation having the signature
+///   i8* (i8*)
+/// where a null input causes a no-op and returns null.
+static llvm::Value *emitARCValueOperation(
+    CodeGenFunction &CGF, llvm::Value *value, llvm::Type *returnType,
+    llvm::Function *&fn, llvm::Intrinsic::ID IntID,
+    llvm::CallInst::TailCallKind tailKind = llvm::CallInst::TCK_None) {
+  if (isa<llvm::ConstantPointerNull>(value))
+    return value;
+
+  if (!fn)
+    fn = getARCIntrinsic(IntID, CGF.CGM);
+
+  // Cast the argument to 'id'.
+  llvm::Type *origType = returnType ? returnType : value->getType();
+  value = CGF.Builder.CreateBitCast(value, CGF.Int8PtrTy);
+
+  // Call the function.
+  llvm::CallInst *call = CGF.EmitNounwindRuntimeCall(fn, value);
+  call->setTailCallKind(tailKind);
+
+  // Cast the result back to the original type.
+  return CGF.Builder.CreateBitCast(call, origType);
+}
+
+/// Perform an operation having the following signature:
+///   i8* (i8**)
+static llvm::Value *emitARCLoadOperation(CodeGenFunction &CGF, Address addr,
+                                         llvm::Function *&fn,
+                                         llvm::Intrinsic::ID IntID) {
+  if (!fn)
+    fn = getARCIntrinsic(IntID, CGF.CGM);
+
+  // Cast the argument to 'id*'.
+  llvm::Type *origType = addr.getElementType();
+  addr = CGF.Builder.CreateBitCast(addr, CGF.Int8PtrPtrTy);
+
+  // Call the function.
+  llvm::Value *result = CGF.EmitNounwindRuntimeCall(fn, addr.getPointer());
+
+  // Cast the result back to a dereference of the original type.
+  if (origType != CGF.Int8PtrTy)
+    result = CGF.Builder.CreateBitCast(result, origType);
+
+  return result;
+}
+
+/// Perform an operation having the following signature:
+///   i8* (i8**, i8*)
+static llvm::Value *emitARCStoreOperation(CodeGenFunction &CGF, Address addr,
+                                          llvm::Value *value,
+                                          llvm::Function *&fn,
+                                          llvm::Intrinsic::ID IntID,
+                                          bool ignored) {
+  assert(addr.getElementType() == value->getType());
+
+  if (!fn)
+    fn = getARCIntrinsic(IntID, CGF.CGM);
+
+  llvm::Type *origType = value->getType();
+
+  llvm::Value *args[] = {
+    CGF.Builder.CreateBitCast(addr.getPointer(), CGF.Int8PtrPtrTy),
+    CGF.Builder.CreateBitCast(value, CGF.Int8PtrTy)
+  };
+  llvm::CallInst *result = CGF.EmitNounwindRuntimeCall(fn, args);
+
+  if (ignored) return nullptr;
+
+  return CGF.Builder.CreateBitCast(result, origType);
+}
+
+/// Perform an operation having the following signature:
+///   void (i8**, i8**)
+static void emitARCCopyOperation(CodeGenFunction &CGF, Address dst, Address src,
+                                 llvm::Function *&fn,
+                                 llvm::Intrinsic::ID IntID) {
+  assert(dst.getType() == src.getType());
+
+  if (!fn)
+    fn = getARCIntrinsic(IntID, CGF.CGM);
+
+  llvm::Value *args[] = {
+    CGF.Builder.CreateBitCast(dst.getPointer(), CGF.Int8PtrPtrTy),
+    CGF.Builder.CreateBitCast(src.getPointer(), CGF.Int8PtrPtrTy)
+  };
+  CGF.EmitNounwindRuntimeCall(fn, args);
+}
+
+/// Perform an operation having the signature
+///   i8* (i8*)
+/// where a null input causes a no-op and returns null.
+static llvm::Value *emitObjCValueOperation(CodeGenFunction &CGF,
+                                           llvm::Value *value,
+                                           llvm::Type *returnType,
+                                           llvm::FunctionCallee &fn,
+                                           StringRef fnName) {
+  if (isa<llvm::ConstantPointerNull>(value))
+    return value;
+
+  if (!fn) {
+    llvm::FunctionType *fnType =
+      llvm::FunctionType::get(CGF.Int8PtrTy, CGF.Int8PtrTy, false);
+    fn = CGF.CGM.CreateRuntimeFunction(fnType, fnName);
+
+    // We have Native ARC, so set nonlazybind attribute for performance
+    if (llvm::Function *f = dyn_cast<llvm::Function>(fn.getCallee()))
+      if (fnName == "objc_retain")
+        f->addFnAttr(llvm::Attribute::NonLazyBind);
+  }
+
+  // Cast the argument to 'id'.
+  llvm::Type *origType = returnType ? returnType : value->getType();
+  value = CGF.Builder.CreateBitCast(value, CGF.Int8PtrTy);
+
+  // Call the function.
+  llvm::CallBase *Inst = CGF.EmitCallOrInvoke(fn, value);
+
+  // Mark calls to objc_autorelease as tail on the assumption that methods
+  // overriding autorelease do not touch anything on the stack.
+  if (fnName == "objc_autorelease")
+    if (auto *Call = dyn_cast<llvm::CallInst>(Inst))
+      Call->setTailCall();
+
+  // Cast the result back to the original type.
+  return CGF.Builder.CreateBitCast(Inst, origType);
+}
+
+/// Produce the code to do a retain.  Based on the type, calls one of:
+///   call i8* \@objc_retain(i8* %value)
+///   call i8* \@objc_retainBlock(i8* %value)
+llvm::Value *CodeGenFunction::EmitARCRetain(QualType type, llvm::Value *value) {
+  if (type->isBlockPointerType())
+    return EmitARCRetainBlock(value, /*mandatory*/ false);
+  else
+    return EmitARCRetainNonBlock(value);
+}
+
+/// Retain the given object, with normal retain semantics.
+///   call i8* \@objc_retain(i8* %value)
+llvm::Value *CodeGenFunction::EmitARCRetainNonBlock(llvm::Value *value) {
+  return emitARCValueOperation(*this, value, nullptr,
+                               CGM.getObjCEntrypoints().objc_retain,
+                               llvm::Intrinsic::objc_retain);
+}
+
+/// Retain the given block, with _Block_copy semantics.
+///   call i8* \@objc_retainBlock(i8* %value)
+///
+/// \param mandatory - If false, emit the call with metadata
+/// indicating that it's okay for the optimizer to eliminate this call
+/// if it can prove that the block never escapes except down the stack.
+llvm::Value *CodeGenFunction::EmitARCRetainBlock(llvm::Value *value,
+                                                 bool mandatory) {
+  llvm::Value *result
+    = emitARCValueOperation(*this, value, nullptr,
+                            CGM.getObjCEntrypoints().objc_retainBlock,
+                            llvm::Intrinsic::objc_retainBlock);
+
+  // If the copy isn't mandatory, add !clang.arc.copy_on_escape to
+  // tell the optimizer that it doesn't need to do this copy if the
+  // block doesn't escape, where being passed as an argument doesn't
+  // count as escaping.
+  if (!mandatory && isa<llvm::Instruction>(result)) {
+    llvm::CallInst *call
+      = cast<llvm::CallInst>(result->stripPointerCasts());
+    assert(call->getCalledOperand() ==
+           CGM.getObjCEntrypoints().objc_retainBlock);
+
+    call->setMetadata("clang.arc.copy_on_escape",
+                      llvm::MDNode::get(Builder.getContext(), None));
+  }
+
+  return result;
+}
+
+static void emitAutoreleasedReturnValueMarker(CodeGenFunction &CGF) {
+  // Fetch the void(void) inline asm which marks that we're going to
+  // do something with the autoreleased return value.
+  llvm::InlineAsm *&marker
+    = CGF.CGM.getObjCEntrypoints().retainAutoreleasedReturnValueMarker;
+  if (!marker) {
+    StringRef assembly
+      = CGF.CGM.getTargetCodeGenInfo()
+           .getARCRetainAutoreleasedReturnValueMarker();
+
+    // If we have an empty assembly string, there's nothing to do.
+    if (assembly.empty()) {
+
+    // Otherwise, at -O0, build an inline asm that we're going to call
+    // in a moment.
+    } else if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0) {
+      llvm::FunctionType *type =
+        llvm::FunctionType::get(CGF.VoidTy, /*variadic*/false);
+
+      marker = llvm::InlineAsm::get(type, assembly, "", /*sideeffects*/ true);
+
+    // If we're at -O1 and above, we don't want to litter the code
+    // with this marker yet, so leave a breadcrumb for the ARC
+    // optimizer to pick up.
+    } else {
+      const char *retainRVMarkerKey = llvm::objcarc::getRVMarkerModuleFlagStr();
+      if (!CGF.CGM.getModule().getModuleFlag(retainRVMarkerKey)) {
+        auto *str = llvm::MDString::get(CGF.getLLVMContext(), assembly);
+        CGF.CGM.getModule().addModuleFlag(llvm::Module::Error,
+                                          retainRVMarkerKey, str);
+      }
+    }
+  }
+
+  // Call the marker asm if we made one, which we do only at -O0.
+  if (marker)
+    CGF.Builder.CreateCall(marker, None, CGF.getBundlesForFunclet(marker));
+}
+
+static llvm::Value *emitOptimizedARCReturnCall(llvm::Value *value,
+                                               bool IsRetainRV,
+                                               CodeGenFunction &CGF) {
+  emitAutoreleasedReturnValueMarker(CGF);
+
+  // Add operand bundle "clang.arc.attachedcall" to the call instead of emitting
+  // retainRV or claimRV calls in the IR. We currently do this only when the
+  // optimization level isn't -O0 since global-isel, which is currently run at
+  // -O0, doesn't know about the operand bundle.
+  ObjCEntrypoints &EPs = CGF.CGM.getObjCEntrypoints();
+  llvm::Function *&EP = IsRetainRV
+                            ? EPs.objc_retainAutoreleasedReturnValue
+                            : EPs.objc_unsafeClaimAutoreleasedReturnValue;
+  llvm::Intrinsic::ID IID =
+      IsRetainRV ? llvm::Intrinsic::objc_retainAutoreleasedReturnValue
+                 : llvm::Intrinsic::objc_unsafeClaimAutoreleasedReturnValue;
+  EP = getARCIntrinsic(IID, CGF.CGM);
+
+  llvm::Triple::ArchType Arch = CGF.CGM.getTriple().getArch();
+
+  // FIXME: Do this on all targets and at -O0 too. This can be enabled only if
+  // the target backend knows how to handle the operand bundle.
+  if (CGF.CGM.getCodeGenOpts().OptimizationLevel > 0 &&
+      (Arch == llvm::Triple::aarch64 || Arch == llvm::Triple::x86_64)) {
+    llvm::Value *bundleArgs[] = {EP};
+    llvm::OperandBundleDef OB("clang.arc.attachedcall", bundleArgs);
+    auto *oldCall = cast<llvm::CallBase>(value);
+    llvm::CallBase *newCall = llvm::CallBase::addOperandBundle(
+        oldCall, llvm::LLVMContext::OB_clang_arc_attachedcall, OB, oldCall);
+    newCall->copyMetadata(*oldCall);
+    oldCall->replaceAllUsesWith(newCall);
+    oldCall->eraseFromParent();
+    CGF.EmitARCNoopIntrinsicUse(newCall);
+    return newCall;
+  }
+
+  bool isNoTail =
+      CGF.CGM.getTargetCodeGenInfo().markARCOptimizedReturnCallsAsNoTail();
+  llvm::CallInst::TailCallKind tailKind =
+      isNoTail ? llvm::CallInst::TCK_NoTail : llvm::CallInst::TCK_None;
+  return emitARCValueOperation(CGF, value, nullptr, EP, IID, tailKind);
+}
+
+/// Retain the given object which is the result of a function call.
+///   call i8* \@objc_retainAutoreleasedReturnValue(i8* %value)
+///
+/// Yes, this function name is one character away from a different
+/// call with completely different semantics.
+llvm::Value *
+CodeGenFunction::EmitARCRetainAutoreleasedReturnValue(llvm::Value *value) {
+  return emitOptimizedARCReturnCall(value, true, *this);
+}
+
+/// Claim a possibly-autoreleased return value at +0.  This is only
+/// valid to do in contexts which do not rely on the retain to keep
+/// the object valid for all of its uses; for example, when
+/// the value is ignored, or when it is being assigned to an
+/// __unsafe_unretained variable.
+///
+///   call i8* \@objc_unsafeClaimAutoreleasedReturnValue(i8* %value)
+llvm::Value *
+CodeGenFunction::EmitARCUnsafeClaimAutoreleasedReturnValue(llvm::Value *value) {
+  return emitOptimizedARCReturnCall(value, false, *this);
+}
+
+/// Release the given object.
+///   call void \@objc_release(i8* %value)
+void CodeGenFunction::EmitARCRelease(llvm::Value *value,
+                                     ARCPreciseLifetime_t precise) {
+  if (isa<llvm::ConstantPointerNull>(value)) return;
+
+  llvm::Function *&fn = CGM.getObjCEntrypoints().objc_release;
+  if (!fn)
+    fn = getARCIntrinsic(llvm::Intrinsic::objc_release, CGM);
+
+  // Cast the argument to 'id'.
+  value = Builder.CreateBitCast(value, Int8PtrTy);
+
+  // Call objc_release.
+  llvm::CallInst *call = EmitNounwindRuntimeCall(fn, value);
+
+  if (precise == ARCImpreciseLifetime) {
+    call->setMetadata("clang.imprecise_release",
+                      llvm::MDNode::get(Builder.getContext(), None));
+  }
+}
+
+/// Destroy a __strong variable.
+///
+/// At -O0, emit a call to store 'null' into the address;
+/// instrumenting tools prefer this because the address is exposed,
+/// but it's relatively cumbersome to optimize.
+///
+/// At -O1 and above, just load and call objc_release.
+///
+///   call void \@objc_storeStrong(i8** %addr, i8* null)
+void CodeGenFunction::EmitARCDestroyStrong(Address addr,
+                                           ARCPreciseLifetime_t precise) {
+  if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
+    llvm::Value *null = getNullForVariable(addr);
+    EmitARCStoreStrongCall(addr, null, /*ignored*/ true);
+    return;
+  }
+
+  llvm::Value *value = Builder.CreateLoad(addr);
+  EmitARCRelease(value, precise);
+}
+
+/// Store into a strong object.  Always calls this:
+///   call void \@objc_storeStrong(i8** %addr, i8* %value)
+llvm::Value *CodeGenFunction::EmitARCStoreStrongCall(Address addr,
+                                                     llvm::Value *value,
+                                                     bool ignored) {
+  assert(addr.getElementType() == value->getType());
+
+  llvm::Function *&fn = CGM.getObjCEntrypoints().objc_storeStrong;
+  if (!fn)
+    fn = getARCIntrinsic(llvm::Intrinsic::objc_storeStrong, CGM);
+
+  llvm::Value *args[] = {
+    Builder.CreateBitCast(addr.getPointer(), Int8PtrPtrTy),
+    Builder.CreateBitCast(value, Int8PtrTy)
+  };
+  EmitNounwindRuntimeCall(fn, args);
+
+  if (ignored) return nullptr;
+  return value;
+}
+
+/// Store into a strong object.  Sometimes calls this:
+///   call void \@objc_storeStrong(i8** %addr, i8* %value)
+/// Other times, breaks it down into components.
+llvm::Value *CodeGenFunction::EmitARCStoreStrong(LValue dst,
+                                                 llvm::Value *newValue,
+                                                 bool ignored) {
+  QualType type = dst.getType();
+  bool isBlock = type->isBlockPointerType();
+
+  // Use a store barrier at -O0 unless this is a block type or the
+  // lvalue is inadequately aligned.
+  if (shouldUseFusedARCCalls() &&
+      !isBlock &&
+      (dst.getAlignment().isZero() ||
+       dst.getAlignment() >= CharUnits::fromQuantity(PointerAlignInBytes))) {
+    return EmitARCStoreStrongCall(dst.getAddress(*this), newValue, ignored);
+  }
+
+  // Otherwise, split it out.
+
+  // Retain the new value.
+  newValue = EmitARCRetain(type, newValue);
+
+  // Read the old value.
+  llvm::Value *oldValue = EmitLoadOfScalar(dst, SourceLocation());
+
+  // Store.  We do this before the release so that any deallocs won't
+  // see the old value.
+  EmitStoreOfScalar(newValue, dst);
+
+  // Finally, release the old value.
+  EmitARCRelease(oldValue, dst.isARCPreciseLifetime());
+
+  return newValue;
+}
+
+/// Autorelease the given object.
+///   call i8* \@objc_autorelease(i8* %value)
+llvm::Value *CodeGenFunction::EmitARCAutorelease(llvm::Value *value) {
+  return emitARCValueOperation(*this, value, nullptr,
+                               CGM.getObjCEntrypoints().objc_autorelease,
+                               llvm::Intrinsic::objc_autorelease);
+}
+
+/// Autorelease the given object.
+///   call i8* \@objc_autoreleaseReturnValue(i8* %value)
+llvm::Value *
+CodeGenFunction::EmitARCAutoreleaseReturnValue(llvm::Value *value) {
+  return emitARCValueOperation(*this, value, nullptr,
+                            CGM.getObjCEntrypoints().objc_autoreleaseReturnValue,
+                               llvm::Intrinsic::objc_autoreleaseReturnValue,
+                               llvm::CallInst::TCK_Tail);
+}
+
+/// Do a fused retain/autorelease of the given object.
+///   call i8* \@objc_retainAutoreleaseReturnValue(i8* %value)
+llvm::Value *
+CodeGenFunction::EmitARCRetainAutoreleaseReturnValue(llvm::Value *value) {
+  return emitARCValueOperation(*this, value, nullptr,
+                     CGM.getObjCEntrypoints().objc_retainAutoreleaseReturnValue,
+                             llvm::Intrinsic::objc_retainAutoreleaseReturnValue,
+                               llvm::CallInst::TCK_Tail);
+}
+
+/// Do a fused retain/autorelease of the given object.
+///   call i8* \@objc_retainAutorelease(i8* %value)
+/// or
+///   %retain = call i8* \@objc_retainBlock(i8* %value)
+///   call i8* \@objc_autorelease(i8* %retain)
+llvm::Value *CodeGenFunction::EmitARCRetainAutorelease(QualType type,
+                                                       llvm::Value *value) {
+  if (!type->isBlockPointerType())
+    return EmitARCRetainAutoreleaseNonBlock(value);
+
+  if (isa<llvm::ConstantPointerNull>(value)) return value;
+
+  llvm::Type *origType = value->getType();
+  value = Builder.CreateBitCast(value, Int8PtrTy);
+  value = EmitARCRetainBlock(value, /*mandatory*/ true);
+  value = EmitARCAutorelease(value);
+  return Builder.CreateBitCast(value, origType);
+}
+
+/// Do a fused retain/autorelease of the given object.
+///   call i8* \@objc_retainAutorelease(i8* %value)
+llvm::Value *
+CodeGenFunction::EmitARCRetainAutoreleaseNonBlock(llvm::Value *value) {
+  return emitARCValueOperation(*this, value, nullptr,
+                               CGM.getObjCEntrypoints().objc_retainAutorelease,
+                               llvm::Intrinsic::objc_retainAutorelease);
+}
+
+/// i8* \@objc_loadWeak(i8** %addr)
+/// Essentially objc_autorelease(objc_loadWeakRetained(addr)).
+llvm::Value *CodeGenFunction::EmitARCLoadWeak(Address addr) {
+  return emitARCLoadOperation(*this, addr,
+                              CGM.getObjCEntrypoints().objc_loadWeak,
+                              llvm::Intrinsic::objc_loadWeak);
+}
+
+/// i8* \@objc_loadWeakRetained(i8** %addr)
+llvm::Value *CodeGenFunction::EmitARCLoadWeakRetained(Address addr) {
+  return emitARCLoadOperation(*this, addr,
+                              CGM.getObjCEntrypoints().objc_loadWeakRetained,
+                              llvm::Intrinsic::objc_loadWeakRetained);
+}
+
+/// i8* \@objc_storeWeak(i8** %addr, i8* %value)
+/// Returns %value.
+llvm::Value *CodeGenFunction::EmitARCStoreWeak(Address addr,
+                                               llvm::Value *value,
+                                               bool ignored) {
+  return emitARCStoreOperation(*this, addr, value,
+                               CGM.getObjCEntrypoints().objc_storeWeak,
+                               llvm::Intrinsic::objc_storeWeak, ignored);
+}
+
+/// i8* \@objc_initWeak(i8** %addr, i8* %value)
+/// Returns %value.  %addr is known to not have a current weak entry.
+/// Essentially equivalent to:
+///   *addr = nil; objc_storeWeak(addr, value);
+void CodeGenFunction::EmitARCInitWeak(Address addr, llvm::Value *value) {
+  // If we're initializing to null, just write null to memory; no need
+  // to get the runtime involved.  But don't do this if optimization
+  // is enabled, because accounting for this would make the optimizer
+  // much more complicated.
+  if (isa<llvm::ConstantPointerNull>(value) &&
+      CGM.getCodeGenOpts().OptimizationLevel == 0) {
+    Builder.CreateStore(value, addr);
+    return;
+  }
+
+  emitARCStoreOperation(*this, addr, value,
+                        CGM.getObjCEntrypoints().objc_initWeak,
+                        llvm::Intrinsic::objc_initWeak, /*ignored*/ true);
+}
+
+/// void \@objc_destroyWeak(i8** %addr)
+/// Essentially objc_storeWeak(addr, nil).
+void CodeGenFunction::EmitARCDestroyWeak(Address addr) {
+  llvm::Function *&fn = CGM.getObjCEntrypoints().objc_destroyWeak;
+  if (!fn)
+    fn = getARCIntrinsic(llvm::Intrinsic::objc_destroyWeak, CGM);
+
+  // Cast the argument to 'id*'.
+  addr = Builder.CreateBitCast(addr, Int8PtrPtrTy);
+
+  EmitNounwindRuntimeCall(fn, addr.getPointer());
+}
+
+/// void \@objc_moveWeak(i8** %dest, i8** %src)
+/// Disregards the current value in %dest.  Leaves %src pointing to nothing.
+/// Essentially (objc_copyWeak(dest, src), objc_destroyWeak(src)).
+void CodeGenFunction::EmitARCMoveWeak(Address dst, Address src) {
+  emitARCCopyOperation(*this, dst, src,
+                       CGM.getObjCEntrypoints().objc_moveWeak,
+                       llvm::Intrinsic::objc_moveWeak);
+}
+
+/// void \@objc_copyWeak(i8** %dest, i8** %src)
+/// Disregards the current value in %dest.  Essentially
+///   objc_release(objc_initWeak(dest, objc_readWeakRetained(src)))
+void CodeGenFunction::EmitARCCopyWeak(Address dst, Address src) {
+  emitARCCopyOperation(*this, dst, src,
+                       CGM.getObjCEntrypoints().objc_copyWeak,
+                       llvm::Intrinsic::objc_copyWeak);
+}
+
+void CodeGenFunction::emitARCCopyAssignWeak(QualType Ty, Address DstAddr,
+                                            Address SrcAddr) {
+  llvm::Value *Object = EmitARCLoadWeakRetained(SrcAddr);
+  Object = EmitObjCConsumeObject(Ty, Object);
+  EmitARCStoreWeak(DstAddr, Object, false);
+}
+
+void CodeGenFunction::emitARCMoveAssignWeak(QualType Ty, Address DstAddr,
+                                            Address SrcAddr) {
+  llvm::Value *Object = EmitARCLoadWeakRetained(SrcAddr);
+  Object = EmitObjCConsumeObject(Ty, Object);
+  EmitARCStoreWeak(DstAddr, Object, false);
+  EmitARCDestroyWeak(SrcAddr);
+}
+
+/// Produce the code to do a objc_autoreleasepool_push.
+///   call i8* \@objc_autoreleasePoolPush(void)
+llvm::Value *CodeGenFunction::EmitObjCAutoreleasePoolPush() {
+  llvm::Function *&fn = CGM.getObjCEntrypoints().objc_autoreleasePoolPush;
+  if (!fn)
+    fn = getARCIntrinsic(llvm::Intrinsic::objc_autoreleasePoolPush, CGM);
+
+  return EmitNounwindRuntimeCall(fn);
+}
+
+/// Produce the code to do a primitive release.
+///   call void \@objc_autoreleasePoolPop(i8* %ptr)
+void CodeGenFunction::EmitObjCAutoreleasePoolPop(llvm::Value *value) {
+  assert(value->getType() == Int8PtrTy);
+
+  if (getInvokeDest()) {
+    // Call the runtime method not the intrinsic if we are handling exceptions
+    llvm::FunctionCallee &fn =
+        CGM.getObjCEntrypoints().objc_autoreleasePoolPopInvoke;
+    if (!fn) {
+      llvm::FunctionType *fnType =
+        llvm::FunctionType::get(Builder.getVoidTy(), Int8PtrTy, false);
+      fn = CGM.CreateRuntimeFunction(fnType, "objc_autoreleasePoolPop");
+      setARCRuntimeFunctionLinkage(CGM, fn);
+    }
+
+    // objc_autoreleasePoolPop can throw.
+    EmitRuntimeCallOrInvoke(fn, value);
+  } else {
+    llvm::FunctionCallee &fn = CGM.getObjCEntrypoints().objc_autoreleasePoolPop;
+    if (!fn)
+      fn = getARCIntrinsic(llvm::Intrinsic::objc_autoreleasePoolPop, CGM);
+
+    EmitRuntimeCall(fn, value);
+  }
+}
+
+/// Produce the code to do an MRR version objc_autoreleasepool_push.
+/// Which is: [[NSAutoreleasePool alloc] init];
+/// Where alloc is declared as: + (id) alloc; in NSAutoreleasePool class.
+/// init is declared as: - (id) init; in its NSObject super class.
+///
+llvm::Value *CodeGenFunction::EmitObjCMRRAutoreleasePoolPush() {
+  CGObjCRuntime &Runtime = CGM.getObjCRuntime();
+  llvm::Value *Receiver = Runtime.EmitNSAutoreleasePoolClassRef(*this);
+  // [NSAutoreleasePool alloc]
+  IdentifierInfo *II = &CGM.getContext().Idents.get("alloc");
+  Selector AllocSel = getContext().Selectors.getSelector(0, &II);
+  CallArgList Args;
+  RValue AllocRV =
+    Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
+                                getContext().getObjCIdType(),
+                                AllocSel, Receiver, Args);
+
+  // [Receiver init]
+  Receiver = AllocRV.getScalarVal();
+  II = &CGM.getContext().Idents.get("init");
+  Selector InitSel = getContext().Selectors.getSelector(0, &II);
+  RValue InitRV =
+    Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
+                                getContext().getObjCIdType(),
+                                InitSel, Receiver, Args);
+  return InitRV.getScalarVal();
+}
+
+/// Allocate the given objc object.
+///   call i8* \@objc_alloc(i8* %value)
+llvm::Value *CodeGenFunction::EmitObjCAlloc(llvm::Value *value,
+                                            llvm::Type *resultType) {
+  return emitObjCValueOperation(*this, value, resultType,
+                                CGM.getObjCEntrypoints().objc_alloc,
+                                "objc_alloc");
+}
+
+/// Allocate the given objc object.
+///   call i8* \@objc_allocWithZone(i8* %value)
+llvm::Value *CodeGenFunction::EmitObjCAllocWithZone(llvm::Value *value,
+                                                    llvm::Type *resultType) {
+  return emitObjCValueOperation(*this, value, resultType,
+                                CGM.getObjCEntrypoints().objc_allocWithZone,
+                                "objc_allocWithZone");
+}
+
+llvm::Value *CodeGenFunction::EmitObjCAllocInit(llvm::Value *value,
+                                                llvm::Type *resultType) {
+  return emitObjCValueOperation(*this, value, resultType,
+                                CGM.getObjCEntrypoints().objc_alloc_init,
+                                "objc_alloc_init");
+}
+
+/// Produce the code to do a primitive release.
+/// [tmp drain];
+void CodeGenFunction::EmitObjCMRRAutoreleasePoolPop(llvm::Value *Arg) {
+  IdentifierInfo *II = &CGM.getContext().Idents.get("drain");
+  Selector DrainSel = getContext().Selectors.getSelector(0, &II);
+  CallArgList Args;
+  CGM.getObjCRuntime().GenerateMessageSend(*this, ReturnValueSlot(),
+                              getContext().VoidTy, DrainSel, Arg, Args);
+}
+
+void CodeGenFunction::destroyARCStrongPrecise(CodeGenFunction &CGF,
+                                              Address addr,
+                                              QualType type) {
+  CGF.EmitARCDestroyStrong(addr, ARCPreciseLifetime);
+}
+
+void CodeGenFunction::destroyARCStrongImprecise(CodeGenFunction &CGF,
+                                                Address addr,
+                                                QualType type) {
+  CGF.EmitARCDestroyStrong(addr, ARCImpreciseLifetime);
+}
+
+void CodeGenFunction::destroyARCWeak(CodeGenFunction &CGF,
+                                     Address addr,
+                                     QualType type) {
+  CGF.EmitARCDestroyWeak(addr);
+}
+
+void CodeGenFunction::emitARCIntrinsicUse(CodeGenFunction &CGF, Address addr,
+                                          QualType type) {
+  llvm::Value *value = CGF.Builder.CreateLoad(addr);
+  CGF.EmitARCIntrinsicUse(value);
+}
+
+/// Autorelease the given object.
+///   call i8* \@objc_autorelease(i8* %value)
+llvm::Value *CodeGenFunction::EmitObjCAutorelease(llvm::Value *value,
+                                                  llvm::Type *returnType) {
+  return emitObjCValueOperation(
+      *this, value, returnType,
+      CGM.getObjCEntrypoints().objc_autoreleaseRuntimeFunction,
+      "objc_autorelease");
+}
+
+/// Retain the given object, with normal retain semantics.
+///   call i8* \@objc_retain(i8* %value)
+llvm::Value *CodeGenFunction::EmitObjCRetainNonBlock(llvm::Value *value,
+                                                     llvm::Type *returnType) {
+  return emitObjCValueOperation(
+      *this, value, returnType,
+      CGM.getObjCEntrypoints().objc_retainRuntimeFunction, "objc_retain");
+}
+
+/// Release the given object.
+///   call void \@objc_release(i8* %value)
+void CodeGenFunction::EmitObjCRelease(llvm::Value *value,
+                                      ARCPreciseLifetime_t precise) {
+  if (isa<llvm::ConstantPointerNull>(value)) return;
+
+  llvm::FunctionCallee &fn =
+      CGM.getObjCEntrypoints().objc_releaseRuntimeFunction;
+  if (!fn) {
+    llvm::FunctionType *fnType =
+        llvm::FunctionType::get(Builder.getVoidTy(), Int8PtrTy, false);
+    fn = CGM.CreateRuntimeFunction(fnType, "objc_release");
+    setARCRuntimeFunctionLinkage(CGM, fn);
+    // We have Native ARC, so set nonlazybind attribute for performance
+    if (llvm::Function *f = dyn_cast<llvm::Function>(fn.getCallee()))
+      f->addFnAttr(llvm::Attribute::NonLazyBind);
+  }
+
+  // Cast the argument to 'id'.
+  value = Builder.CreateBitCast(value, Int8PtrTy);
+
+  // Call objc_release.
+  llvm::CallBase *call = EmitCallOrInvoke(fn, value);
+
+  if (precise == ARCImpreciseLifetime) {
+    call->setMetadata("clang.imprecise_release",
+                      llvm::MDNode::get(Builder.getContext(), None));
+  }
+}
+
+namespace {
+  struct CallObjCAutoreleasePoolObject final : EHScopeStack::Cleanup {
+    llvm::Value *Token;
+
+    CallObjCAutoreleasePoolObject(llvm::Value *token) : Token(token) {}
+
+    void Emit(CodeGenFunction &CGF, Flags flags) override {
+      CGF.EmitObjCAutoreleasePoolPop(Token);
+    }
+  };
+  struct CallObjCMRRAutoreleasePoolObject final : EHScopeStack::Cleanup {
+    llvm::Value *Token;
+
+    CallObjCMRRAutoreleasePoolObject(llvm::Value *token) : Token(token) {}
+
+    void Emit(CodeGenFunction &CGF, Flags flags) override {
+      CGF.EmitObjCMRRAutoreleasePoolPop(Token);
+    }
+  };
+}
+
+void CodeGenFunction::EmitObjCAutoreleasePoolCleanup(llvm::Value *Ptr) {
+  if (CGM.getLangOpts().ObjCAutoRefCount)
+    EHStack.pushCleanup<CallObjCAutoreleasePoolObject>(NormalCleanup, Ptr);
+  else
+    EHStack.pushCleanup<CallObjCMRRAutoreleasePoolObject>(NormalCleanup, Ptr);
+}
+
+static bool shouldRetainObjCLifetime(Qualifiers::ObjCLifetime lifetime) {
+  switch (lifetime) {
+  case Qualifiers::OCL_None:
+  case Qualifiers::OCL_ExplicitNone:
+  case Qualifiers::OCL_Strong:
+  case Qualifiers::OCL_Autoreleasing:
+    return true;
+
+  case Qualifiers::OCL_Weak:
+    return false;
+  }
+
+  llvm_unreachable("impossible lifetime!");
+}
+
+static TryEmitResult tryEmitARCRetainLoadOfScalar(CodeGenFunction &CGF,
+                                                  LValue lvalue,
+                                                  QualType type) {
+  llvm::Value *result;
+  bool shouldRetain = shouldRetainObjCLifetime(type.getObjCLifetime());
+  if (shouldRetain) {
+    result = CGF.EmitLoadOfLValue(lvalue, SourceLocation()).getScalarVal();
+  } else {
+    assert(type.getObjCLifetime() == Qualifiers::OCL_Weak);
+    result = CGF.EmitARCLoadWeakRetained(lvalue.getAddress(CGF));
+  }
+  return TryEmitResult(result, !shouldRetain);
+}
+
+static TryEmitResult tryEmitARCRetainLoadOfScalar(CodeGenFunction &CGF,
+                                                  const Expr *e) {
+  e = e->IgnoreParens();
+  QualType type = e->getType();
+
+  // If we're loading retained from a __strong xvalue, we can avoid
+  // an extra retain/release pair by zeroing out the source of this
+  // "move" operation.
+  if (e->isXValue() &&
+      !type.isConstQualified() &&
+      type.getObjCLifetime() == Qualifiers::OCL_Strong) {
+    // Emit the lvalue.
+    LValue lv = CGF.EmitLValue(e);
+
+    // Load the object pointer.
+    llvm::Value *result = CGF.EmitLoadOfLValue(lv,
+                                               SourceLocation()).getScalarVal();
+
+    // Set the source pointer to NULL.
+    CGF.EmitStoreOfScalar(getNullForVariable(lv.getAddress(CGF)), lv);
+
+    return TryEmitResult(result, true);
+  }
+
+  // As a very special optimization, in ARC++, if the l-value is the
+  // result of a non-volatile assignment, do a simple retain of the
+  // result of the call to objc_storeWeak instead of reloading.
+  if (CGF.getLangOpts().CPlusPlus &&
+      !type.isVolatileQualified() &&
+      type.getObjCLifetime() == Qualifiers::OCL_Weak &&
+      isa<BinaryOperator>(e) &&
+      cast<BinaryOperator>(e)->getOpcode() == BO_Assign)
+    return TryEmitResult(CGF.EmitScalarExpr(e), false);
+
+  // Try to emit code for scalar constant instead of emitting LValue and
+  // loading it because we are not guaranteed to have an l-value. One of such
+  // cases is DeclRefExpr referencing non-odr-used constant-evaluated variable.
+  if (const auto *decl_expr = dyn_cast<DeclRefExpr>(e)) {
+    auto *DRE = const_cast<DeclRefExpr *>(decl_expr);
+    if (CodeGenFunction::ConstantEmission constant = CGF.tryEmitAsConstant(DRE))
+      return TryEmitResult(CGF.emitScalarConstant(constant, DRE),
+                           !shouldRetainObjCLifetime(type.getObjCLifetime()));
+  }
+
+  return tryEmitARCRetainLoadOfScalar(CGF, CGF.EmitLValue(e), type);
+}
+
+typedef llvm::function_ref<llvm::Value *(CodeGenFunction &CGF,
+                                         llvm::Value *value)>
+  ValueTransform;
+
+/// Insert code immediately after a call.
+
+// FIXME: We should find a way to emit the runtime call immediately
+// after the call is emitted to eliminate the need for this function.
+static llvm::Value *emitARCOperationAfterCall(CodeGenFunction &CGF,
+                                              llvm::Value *value,
+                                              ValueTransform doAfterCall,
+                                              ValueTransform doFallback) {
+  CGBuilderTy::InsertPoint ip = CGF.Builder.saveIP();
+  auto *callBase = dyn_cast<llvm::CallBase>(value);
+
+  if (callBase && llvm::objcarc::hasAttachedCallOpBundle(callBase)) {
+    // Fall back if the call base has operand bundle "clang.arc.attachedcall".
+    value = doFallback(CGF, value);
+  } else if (llvm::CallInst *call = dyn_cast<llvm::CallInst>(value)) {
+    // Place the retain immediately following the call.
+    CGF.Builder.SetInsertPoint(call->getParent(),
+                               ++llvm::BasicBlock::iterator(call));
+    value = doAfterCall(CGF, value);
+  } else if (llvm::InvokeInst *invoke = dyn_cast<llvm::InvokeInst>(value)) {
+    // Place the retain at the beginning of the normal destination block.
+    llvm::BasicBlock *BB = invoke->getNormalDest();
+    CGF.Builder.SetInsertPoint(BB, BB->begin());
+    value = doAfterCall(CGF, value);
+
+  // Bitcasts can arise because of related-result returns.  Rewrite
+  // the operand.
+  } else if (llvm::BitCastInst *bitcast = dyn_cast<llvm::BitCastInst>(value)) {
+    // Change the insert point to avoid emitting the fall-back call after the
+    // bitcast.
+    CGF.Builder.SetInsertPoint(bitcast->getParent(), bitcast->getIterator());
+    llvm::Value *operand = bitcast->getOperand(0);
+    operand = emitARCOperationAfterCall(CGF, operand, doAfterCall, doFallback);
+    bitcast->setOperand(0, operand);
+    value = bitcast;
+  } else {
+    auto *phi = dyn_cast<llvm::PHINode>(value);
+    if (phi && phi->getNumIncomingValues() == 2 &&
+        isa<llvm::ConstantPointerNull>(phi->getIncomingValue(1)) &&
+        isa<llvm::CallBase>(phi->getIncomingValue(0))) {
+      // Handle phi instructions that are generated when it's necessary to check
+      // whether the receiver of a message is null.
+      llvm::Value *inVal = phi->getIncomingValue(0);
+      inVal = emitARCOperationAfterCall(CGF, inVal, doAfterCall, doFallback);
+      phi->setIncomingValue(0, inVal);
+      value = phi;
+    } else {
+      // Generic fall-back case.
+      // Retain using the non-block variant: we never need to do a copy
+      // of a block that's been returned to us.
+      value = doFallback(CGF, value);
+    }
+  }
+
+  CGF.Builder.restoreIP(ip);
+  return value;
+}
+
+/// Given that the given expression is some sort of call (which does
+/// not return retained), emit a retain following it.
+static llvm::Value *emitARCRetainCallResult(CodeGenFunction &CGF,
+                                            const Expr *e) {
+  llvm::Value *value = CGF.EmitScalarExpr(e);
+  return emitARCOperationAfterCall(CGF, value,
+           [](CodeGenFunction &CGF, llvm::Value *value) {
+             return CGF.EmitARCRetainAutoreleasedReturnValue(value);
+           },
+           [](CodeGenFunction &CGF, llvm::Value *value) {
+             return CGF.EmitARCRetainNonBlock(value);
+           });
+}
+
+/// Given that the given expression is some sort of call (which does
+/// not return retained), perform an unsafeClaim following it.
+static llvm::Value *emitARCUnsafeClaimCallResult(CodeGenFunction &CGF,
+                                                 const Expr *e) {
+  llvm::Value *value = CGF.EmitScalarExpr(e);
+  return emitARCOperationAfterCall(CGF, value,
+           [](CodeGenFunction &CGF, llvm::Value *value) {
+             return CGF.EmitARCUnsafeClaimAutoreleasedReturnValue(value);
+           },
+           [](CodeGenFunction &CGF, llvm::Value *value) {
+             return value;
+           });
+}
+
+llvm::Value *CodeGenFunction::EmitARCReclaimReturnedObject(const Expr *E,
+                                                      bool allowUnsafeClaim) {
+  if (allowUnsafeClaim &&
+      CGM.getLangOpts().ObjCRuntime.hasARCUnsafeClaimAutoreleasedReturnValue()) {
+    return emitARCUnsafeClaimCallResult(*this, E);
+  } else {
+    llvm::Value *value = emitARCRetainCallResult(*this, E);
+    return EmitObjCConsumeObject(E->getType(), value);
+  }
+}
+
+/// Determine whether it might be important to emit a separate
+/// objc_retain_block on the result of the given expression, or
+/// whether it's okay to just emit it in a +1 context.
+static bool shouldEmitSeparateBlockRetain(const Expr *e) {
+  assert(e->getType()->isBlockPointerType());
+  e = e->IgnoreParens();
+
+  // For future goodness, emit block expressions directly in +1
+  // contexts if we can.
+  if (isa<BlockExpr>(e))
+    return false;
+
+  if (const CastExpr *cast = dyn_cast<CastExpr>(e)) {
+    switch (cast->getCastKind()) {
+    // Emitting these operations in +1 contexts is goodness.
+    case CK_LValueToRValue:
+    case CK_ARCReclaimReturnedObject:
+    case CK_ARCConsumeObject:
+    case CK_ARCProduceObject:
+      return false;
+
+    // These operations preserve a block type.
+    case CK_NoOp:
+    case CK_BitCast:
+      return shouldEmitSeparateBlockRetain(cast->getSubExpr());
+
+    // These operations are known to be bad (or haven't been considered).
+    case CK_AnyPointerToBlockPointerCast:
+    default:
+      return true;
+    }
+  }
+
+  return true;
+}
+
+namespace {
+/// A CRTP base class for emitting expressions of retainable object
+/// pointer type in ARC.
+template <typename Impl, typename Result> class ARCExprEmitter {
+protected:
+  CodeGenFunction &CGF;
+  Impl &asImpl() { return *static_cast<Impl*>(this); }
+
+  ARCExprEmitter(CodeGenFunction &CGF) : CGF(CGF) {}
+
+public:
+  Result visit(const Expr *e);
+  Result visitCastExpr(const CastExpr *e);
+  Result visitPseudoObjectExpr(const PseudoObjectExpr *e);
+  Result visitBlockExpr(const BlockExpr *e);
+  Result visitBinaryOperator(const BinaryOperator *e);
+  Result visitBinAssign(const BinaryOperator *e);
+  Result visitBinAssignUnsafeUnretained(const BinaryOperator *e);
+  Result visitBinAssignAutoreleasing(const BinaryOperator *e);
+  Result visitBinAssignWeak(const BinaryOperator *e);
+  Result visitBinAssignStrong(const BinaryOperator *e);
+
+  // Minimal implementation:
+  //   Result visitLValueToRValue(const Expr *e)
+  //   Result visitConsumeObject(const Expr *e)
+  //   Result visitExtendBlockObject(const Expr *e)
+  //   Result visitReclaimReturnedObject(const Expr *e)
+  //   Result visitCall(const Expr *e)
+  //   Result visitExpr(const Expr *e)
+  //
+  //   Result emitBitCast(Result result, llvm::Type *resultType)
+  //   llvm::Value *getValueOfResult(Result result)
+};
+}
+
+/// Try to emit a PseudoObjectExpr under special ARC rules.
+///
+/// This massively duplicates emitPseudoObjectRValue.
+template <typename Impl, typename Result>
+Result
+ARCExprEmitter<Impl,Result>::visitPseudoObjectExpr(const PseudoObjectExpr *E) {
+  SmallVector<CodeGenFunction::OpaqueValueMappingData, 4> opaques;
+
+  // Find the result expression.
+  const Expr *resultExpr = E->getResultExpr();
+  assert(resultExpr);
+  Result result;
+
+  for (PseudoObjectExpr::const_semantics_iterator
+         i = E->semantics_begin(), e = E->semantics_end(); i != e; ++i) {
+    const Expr *semantic = *i;
+
+    // If this semantic expression is an opaque value, bind it
+    // to the result of its source expression.
+    if (const OpaqueValueExpr *ov = dyn_cast<OpaqueValueExpr>(semantic)) {
+      typedef CodeGenFunction::OpaqueValueMappingData OVMA;
+      OVMA opaqueData;
+
+      // If this semantic is the result of the pseudo-object
+      // expression, try to evaluate the source as +1.
+      if (ov == resultExpr) {
+        assert(!OVMA::shouldBindAsLValue(ov));
+        result = asImpl().visit(ov->getSourceExpr());
+        opaqueData = OVMA::bind(CGF, ov,
+                            RValue::get(asImpl().getValueOfResult(result)));
+
+      // Otherwise, just bind it.
+      } else {
+        opaqueData = OVMA::bind(CGF, ov, ov->getSourceExpr());
+      }
+      opaques.push_back(opaqueData);
+
+    // Otherwise, if the expression is the result, evaluate it
+    // and remember the result.
+    } else if (semantic == resultExpr) {
+      result = asImpl().visit(semantic);
+
+    // Otherwise, evaluate the expression in an ignored context.
+    } else {
+      CGF.EmitIgnoredExpr(semantic);
+    }
+  }
+
+  // Unbind all the opaques now.
+  for (unsigned i = 0, e = opaques.size(); i != e; ++i)
+    opaques[i].unbind(CGF);
+
+  return result;
+}
+
+template <typename Impl, typename Result>
+Result ARCExprEmitter<Impl, Result>::visitBlockExpr(const BlockExpr *e) {
+  // The default implementation just forwards the expression to visitExpr.
+  return asImpl().visitExpr(e);
+}
+
+template <typename Impl, typename Result>
+Result ARCExprEmitter<Impl,Result>::visitCastExpr(const CastExpr *e) {
+  switch (e->getCastKind()) {
+
+  // No-op casts don't change the type, so we just ignore them.
+  case CK_NoOp:
+    return asImpl().visit(e->getSubExpr());
+
+  // These casts can change the type.
+  case CK_CPointerToObjCPointerCast:
+  case CK_BlockPointerToObjCPointerCast:
+  case CK_AnyPointerToBlockPointerCast:
+  case CK_BitCast: {
+    llvm::Type *resultType = CGF.ConvertType(e->getType());
+    assert(e->getSubExpr()->getType()->hasPointerRepresentation());
+    Result result = asImpl().visit(e->getSubExpr());
+    return asImpl().emitBitCast(result, resultType);
+  }
+
+  // Handle some casts specially.
+  case CK_LValueToRValue:
+    return asImpl().visitLValueToRValue(e->getSubExpr());
+  case CK_ARCConsumeObject:
+    return asImpl().visitConsumeObject(e->getSubExpr());
+  case CK_ARCExtendBlockObject:
+    return asImpl().visitExtendBlockObject(e->getSubExpr());
+  case CK_ARCReclaimReturnedObject:
+    return asImpl().visitReclaimReturnedObject(e->getSubExpr());
+
+  // Otherwise, use the default logic.
+  default:
+    return asImpl().visitExpr(e);
+  }
+}
+
+template <typename Impl, typename Result>
+Result
+ARCExprEmitter<Impl,Result>::visitBinaryOperator(const BinaryOperator *e) {
+  switch (e->getOpcode()) {
+  case BO_Comma:
+    CGF.EmitIgnoredExpr(e->getLHS());
+    CGF.EnsureInsertPoint();
+    return asImpl().visit(e->getRHS());
+
+  case BO_Assign:
+    return asImpl().visitBinAssign(e);
+
+  default:
+    return asImpl().visitExpr(e);
+  }
+}
+
+template <typename Impl, typename Result>
+Result ARCExprEmitter<Impl,Result>::visitBinAssign(const BinaryOperator *e) {
+  switch (e->getLHS()->getType().getObjCLifetime()) {
+  case Qualifiers::OCL_ExplicitNone:
+    return asImpl().visitBinAssignUnsafeUnretained(e);
+
+  case Qualifiers::OCL_Weak:
+    return asImpl().visitBinAssignWeak(e);
+
+  case Qualifiers::OCL_Autoreleasing:
+    return asImpl().visitBinAssignAutoreleasing(e);
+
+  case Qualifiers::OCL_Strong:
+    return asImpl().visitBinAssignStrong(e);
+
+  case Qualifiers::OCL_None:
+    return asImpl().visitExpr(e);
+  }
+  llvm_unreachable("bad ObjC ownership qualifier");
+}
+
+/// The default rule for __unsafe_unretained emits the RHS recursively,
+/// stores into the unsafe variable, and propagates the result outward.
+template <typename Impl, typename Result>
+Result ARCExprEmitter<Impl,Result>::
+                    visitBinAssignUnsafeUnretained(const BinaryOperator *e) {
+  // Recursively emit the RHS.
+  // For __block safety, do this before emitting the LHS.
+  Result result = asImpl().visit(e->getRHS());
+
+  // Perform the store.
+  LValue lvalue =
+    CGF.EmitCheckedLValue(e->getLHS(), CodeGenFunction::TCK_Store);
+  CGF.EmitStoreThroughLValue(RValue::get(asImpl().getValueOfResult(result)),
+                             lvalue);
+
+  return result;
+}
+
+template <typename Impl, typename Result>
+Result
+ARCExprEmitter<Impl,Result>::visitBinAssignAutoreleasing(const BinaryOperator *e) {
+  return asImpl().visitExpr(e);
+}
+
+template <typename Impl, typename Result>
+Result
+ARCExprEmitter<Impl,Result>::visitBinAssignWeak(const BinaryOperator *e) {
+  return asImpl().visitExpr(e);
+}
+
+template <typename Impl, typename Result>
+Result
+ARCExprEmitter<Impl,Result>::visitBinAssignStrong(const BinaryOperator *e) {
+  return asImpl().visitExpr(e);
+}
+
+/// The general expression-emission logic.
+template <typename Impl, typename Result>
+Result ARCExprEmitter<Impl,Result>::visit(const Expr *e) {
+  // We should *never* see a nested full-expression here, because if
+  // we fail to emit at +1, our caller must not retain after we close
+  // out the full-expression.  This isn't as important in the unsafe
+  // emitter.
+  assert(!isa<ExprWithCleanups>(e));
+
+  // Look through parens, __extension__, generic selection, etc.
+  e = e->IgnoreParens();
+
+  // Handle certain kinds of casts.
+  if (const CastExpr *ce = dyn_cast<CastExpr>(e)) {
+    return asImpl().visitCastExpr(ce);
+
+  // Handle the comma operator.
+  } else if (auto op = dyn_cast<BinaryOperator>(e)) {
+    return asImpl().visitBinaryOperator(op);
+
+  // TODO: handle conditional operators here
+
+  // For calls and message sends, use the retained-call logic.
+  // Delegate inits are a special case in that they're the only
+  // returns-retained expression that *isn't* surrounded by
+  // a consume.
+  } else if (isa<CallExpr>(e) ||
+             (isa<ObjCMessageExpr>(e) &&
+              !cast<ObjCMessageExpr>(e)->isDelegateInitCall())) {
+    return asImpl().visitCall(e);
+
+  // Look through pseudo-object expressions.
+  } else if (const PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) {
+    return asImpl().visitPseudoObjectExpr(pseudo);
+  } else if (auto *be = dyn_cast<BlockExpr>(e))
+    return asImpl().visitBlockExpr(be);
+
+  return asImpl().visitExpr(e);
+}
+
+namespace {
+
+/// An emitter for +1 results.
+struct ARCRetainExprEmitter :
+  public ARCExprEmitter<ARCRetainExprEmitter, TryEmitResult> {
+
+  ARCRetainExprEmitter(CodeGenFunction &CGF) : ARCExprEmitter(CGF) {}
+
+  llvm::Value *getValueOfResult(TryEmitResult result) {
+    return result.getPointer();
+  }
+
+  TryEmitResult emitBitCast(TryEmitResult result, llvm::Type *resultType) {
+    llvm::Value *value = result.getPointer();
+    value = CGF.Builder.CreateBitCast(value, resultType);
+    result.setPointer(value);
+    return result;
+  }
+
+  TryEmitResult visitLValueToRValue(const Expr *e) {
+    return tryEmitARCRetainLoadOfScalar(CGF, e);
+  }
+
+  /// For consumptions, just emit the subexpression and thus elide
+  /// the retain/release pair.
+  TryEmitResult visitConsumeObject(const Expr *e) {
+    llvm::Value *result = CGF.EmitScalarExpr(e);
+    return TryEmitResult(result, true);
+  }
+
+  TryEmitResult visitBlockExpr(const BlockExpr *e) {
+    TryEmitResult result = visitExpr(e);
+    // Avoid the block-retain if this is a block literal that doesn't need to be
+    // copied to the heap.
+    if (CGF.CGM.getCodeGenOpts().ObjCAvoidHeapifyLocalBlocks &&
+        e->getBlockDecl()->canAvoidCopyToHeap())
+      result.setInt(true);
+    return result;
+  }
+
+  /// Block extends are net +0.  Naively, we could just recurse on
+  /// the subexpression, but actually we need to ensure that the
+  /// value is copied as a block, so there's a little filter here.
+  TryEmitResult visitExtendBlockObject(const Expr *e) {
+    llvm::Value *result; // will be a +0 value
+
+    // If we can't safely assume the sub-expression will produce a
+    // block-copied value, emit the sub-expression at +0.
+    if (shouldEmitSeparateBlockRetain(e)) {
+      result = CGF.EmitScalarExpr(e);
+
+    // Otherwise, try to emit the sub-expression at +1 recursively.
+    } else {
+      TryEmitResult subresult = asImpl().visit(e);
+
+      // If that produced a retained value, just use that.
+      if (subresult.getInt()) {
+        return subresult;
+      }
+
+      // Otherwise it's +0.
+      result = subresult.getPointer();
+    }
+
+    // Retain the object as a block.
+    result = CGF.EmitARCRetainBlock(result, /*mandatory*/ true);
+    return TryEmitResult(result, true);
+  }
+
+  /// For reclaims, emit the subexpression as a retained call and
+  /// skip the consumption.
+  TryEmitResult visitReclaimReturnedObject(const Expr *e) {
+    llvm::Value *result = emitARCRetainCallResult(CGF, e);
+    return TryEmitResult(result, true);
+  }
+
+  /// When we have an undecorated call, retroactively do a claim.
+  TryEmitResult visitCall(const Expr *e) {
+    llvm::Value *result = emitARCRetainCallResult(CGF, e);
+    return TryEmitResult(result, true);
+  }
+
+  // TODO: maybe special-case visitBinAssignWeak?
+
+  TryEmitResult visitExpr(const Expr *e) {
+    // We didn't find an obvious production, so emit what we've got and
+    // tell the caller that we didn't manage to retain.
+    llvm::Value *result = CGF.EmitScalarExpr(e);
+    return TryEmitResult(result, false);
+  }
+};
+}
+
+static TryEmitResult
+tryEmitARCRetainScalarExpr(CodeGenFunction &CGF, const Expr *e) {
+  return ARCRetainExprEmitter(CGF).visit(e);
+}
+
+static llvm::Value *emitARCRetainLoadOfScalar(CodeGenFunction &CGF,
+                                                LValue lvalue,
+                                                QualType type) {
+  TryEmitResult result = tryEmitARCRetainLoadOfScalar(CGF, lvalue, type);
+  llvm::Value *value = result.getPointer();
+  if (!result.getInt())
+    value = CGF.EmitARCRetain(type, value);
+  return value;
+}
+
+/// EmitARCRetainScalarExpr - Semantically equivalent to
+/// EmitARCRetainObject(e->getType(), EmitScalarExpr(e)), but making a
+/// best-effort attempt to peephole expressions that naturally produce
+/// retained objects.
+llvm::Value *CodeGenFunction::EmitARCRetainScalarExpr(const Expr *e) {
+  // The retain needs to happen within the full-expression.
+  if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
+    RunCleanupsScope scope(*this);
+    return EmitARCRetainScalarExpr(cleanups->getSubExpr());
+  }
+
+  TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e);
+  llvm::Value *value = result.getPointer();
+  if (!result.getInt())
+    value = EmitARCRetain(e->getType(), value);
+  return value;
+}
+
+llvm::Value *
+CodeGenFunction::EmitARCRetainAutoreleaseScalarExpr(const Expr *e) {
+  // The retain needs to happen within the full-expression.
+  if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
+    RunCleanupsScope scope(*this);
+    return EmitARCRetainAutoreleaseScalarExpr(cleanups->getSubExpr());
+  }
+
+  TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e);
+  llvm::Value *value = result.getPointer();
+  if (result.getInt())
+    value = EmitARCAutorelease(value);
+  else
+    value = EmitARCRetainAutorelease(e->getType(), value);
+  return value;
+}
+
+llvm::Value *CodeGenFunction::EmitARCExtendBlockObject(const Expr *e) {
+  llvm::Value *result;
+  bool doRetain;
+
+  if (shouldEmitSeparateBlockRetain(e)) {
+    result = EmitScalarExpr(e);
+    doRetain = true;
+  } else {
+    TryEmitResult subresult = tryEmitARCRetainScalarExpr(*this, e);
+    result = subresult.getPointer();
+    doRetain = !subresult.getInt();
+  }
+
+  if (doRetain)
+    result = EmitARCRetainBlock(result, /*mandatory*/ true);
+  return EmitObjCConsumeObject(e->getType(), result);
+}
+
+llvm::Value *CodeGenFunction::EmitObjCThrowOperand(const Expr *expr) {
+  // In ARC, retain and autorelease the expression.
+  if (getLangOpts().ObjCAutoRefCount) {
+    // Do so before running any cleanups for the full-expression.
+    // EmitARCRetainAutoreleaseScalarExpr does this for us.
+    return EmitARCRetainAutoreleaseScalarExpr(expr);
+  }
+
+  // Otherwise, use the normal scalar-expression emission.  The
+  // exception machinery doesn't do anything special with the
+  // exception like retaining it, so there's no safety associated with
+  // only running cleanups after the throw has started, and when it
+  // matters it tends to be substantially inferior code.
+  return EmitScalarExpr(expr);
+}
+
+namespace {
+
+/// An emitter for assigning into an __unsafe_unretained context.
+struct ARCUnsafeUnretainedExprEmitter :
+  public ARCExprEmitter<ARCUnsafeUnretainedExprEmitter, llvm::Value*> {
+
+  ARCUnsafeUnretainedExprEmitter(CodeGenFunction &CGF) : ARCExprEmitter(CGF) {}
+
+  llvm::Value *getValueOfResult(llvm::Value *value) {
+    return value;
+  }
+
+  llvm::Value *emitBitCast(llvm::Value *value, llvm::Type *resultType) {
+    return CGF.Builder.CreateBitCast(value, resultType);
+  }
+
+  llvm::Value *visitLValueToRValue(const Expr *e) {
+    return CGF.EmitScalarExpr(e);
+  }
+
+  /// For consumptions, just emit the subexpression and perform the
+  /// consumption like normal.
+  llvm::Value *visitConsumeObject(const Expr *e) {
+    llvm::Value *value = CGF.EmitScalarExpr(e);
+    return CGF.EmitObjCConsumeObject(e->getType(), value);
+  }
+
+  /// No special logic for block extensions.  (This probably can't
+  /// actually happen in this emitter, though.)
+  llvm::Value *visitExtendBlockObject(const Expr *e) {
+    return CGF.EmitARCExtendBlockObject(e);
+  }
+
+  /// For reclaims, perform an unsafeClaim if that's enabled.
+  llvm::Value *visitReclaimReturnedObject(const Expr *e) {
+    return CGF.EmitARCReclaimReturnedObject(e, /*unsafe*/ true);
+  }
+
+  /// When we have an undecorated call, just emit it without adding
+  /// the unsafeClaim.
+  llvm::Value *visitCall(const Expr *e) {
+    return CGF.EmitScalarExpr(e);
+  }
+
+  /// Just do normal scalar emission in the default case.
+  llvm::Value *visitExpr(const Expr *e) {
+    return CGF.EmitScalarExpr(e);
+  }
+};
+}
+
+static llvm::Value *emitARCUnsafeUnretainedScalarExpr(CodeGenFunction &CGF,
+                                                      const Expr *e) {
+  return ARCUnsafeUnretainedExprEmitter(CGF).visit(e);
+}
+
+/// EmitARCUnsafeUnretainedScalarExpr - Semantically equivalent to
+/// immediately releasing the resut of EmitARCRetainScalarExpr, but
+/// avoiding any spurious retains, including by performing reclaims
+/// with objc_unsafeClaimAutoreleasedReturnValue.
+llvm::Value *CodeGenFunction::EmitARCUnsafeUnretainedScalarExpr(const Expr *e) {
+  // Look through full-expressions.
+  if (const ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(e)) {
+    RunCleanupsScope scope(*this);
+    return emitARCUnsafeUnretainedScalarExpr(*this, cleanups->getSubExpr());
+  }
+
+  return emitARCUnsafeUnretainedScalarExpr(*this, e);
+}
+
+std::pair<LValue,llvm::Value*>
+CodeGenFunction::EmitARCStoreUnsafeUnretained(const BinaryOperator *e,
+                                              bool ignored) {
+  // Evaluate the RHS first.  If we're ignoring the result, assume
+  // that we can emit at an unsafe +0.
+  llvm::Value *value;
+  if (ignored) {
+    value = EmitARCUnsafeUnretainedScalarExpr(e->getRHS());
+  } else {
+    value = EmitScalarExpr(e->getRHS());
+  }
+
+  // Emit the LHS and perform the store.
+  LValue lvalue = EmitLValue(e->getLHS());
+  EmitStoreOfScalar(value, lvalue);
+
+  return std::pair<LValue,llvm::Value*>(std::move(lvalue), value);
+}
+
+std::pair<LValue,llvm::Value*>
+CodeGenFunction::EmitARCStoreStrong(const BinaryOperator *e,
+                                    bool ignored) {
+  // Evaluate the RHS first.
+  TryEmitResult result = tryEmitARCRetainScalarExpr(*this, e->getRHS());
+  llvm::Value *value = result.getPointer();
+
+  bool hasImmediateRetain = result.getInt();
+
+  // If we didn't emit a retained object, and the l-value is of block
+  // type, then we need to emit the block-retain immediately in case
+  // it invalidates the l-value.
+  if (!hasImmediateRetain && e->getType()->isBlockPointerType()) {
+    value = EmitARCRetainBlock(value, /*mandatory*/ false);
+    hasImmediateRetain = true;
+  }
+
+  LValue lvalue = EmitLValue(e->getLHS());
+
+  // If the RHS was emitted retained, expand this.
+  if (hasImmediateRetain) {
+    llvm::Value *oldValue = EmitLoadOfScalar(lvalue, SourceLocation());
+    EmitStoreOfScalar(value, lvalue);
+    EmitARCRelease(oldValue, lvalue.isARCPreciseLifetime());
+  } else {
+    value = EmitARCStoreStrong(lvalue, value, ignored);
+  }
+
+  return std::pair<LValue,llvm::Value*>(lvalue, value);
+}
+
+std::pair<LValue,llvm::Value*>
+CodeGenFunction::EmitARCStoreAutoreleasing(const BinaryOperator *e) {
+  llvm::Value *value = EmitARCRetainAutoreleaseScalarExpr(e->getRHS());
+  LValue lvalue = EmitLValue(e->getLHS());
+
+  EmitStoreOfScalar(value, lvalue);
+
+  return std::pair<LValue,llvm::Value*>(lvalue, value);
+}
+
+void CodeGenFunction::EmitObjCAutoreleasePoolStmt(
+                                          const ObjCAutoreleasePoolStmt &ARPS) {
+  const Stmt *subStmt = ARPS.getSubStmt();
+  const CompoundStmt &S = cast<CompoundStmt>(*subStmt);
+
+  CGDebugInfo *DI = getDebugInfo();
+  if (DI)
+    DI->EmitLexicalBlockStart(Builder, S.getLBracLoc());
+
+  // Keep track of the current cleanup stack depth.
+  RunCleanupsScope Scope(*this);
+  if (CGM.getLangOpts().ObjCRuntime.hasNativeARC()) {
+    llvm::Value *token = EmitObjCAutoreleasePoolPush();
+    EHStack.pushCleanup<CallObjCAutoreleasePoolObject>(NormalCleanup, token);
+  } else {
+    llvm::Value *token = EmitObjCMRRAutoreleasePoolPush();
+    EHStack.pushCleanup<CallObjCMRRAutoreleasePoolObject>(NormalCleanup, token);
+  }
+
+  for (const auto *I : S.body())
+    EmitStmt(I);
+
+  if (DI)
+    DI->EmitLexicalBlockEnd(Builder, S.getRBracLoc());
+}
+
+/// EmitExtendGCLifetime - Given a pointer to an Objective-C object,
+/// make sure it survives garbage collection until this point.
+void CodeGenFunction::EmitExtendGCLifetime(llvm::Value *object) {
+  // We just use an inline assembly.
+  llvm::FunctionType *extenderType
+    = llvm::FunctionType::get(VoidTy, VoidPtrTy, RequiredArgs::All);
+  llvm::InlineAsm *extender = llvm::InlineAsm::get(extenderType,
+                                                   /* assembly */ "",
+                                                   /* constraints */ "r",
+                                                   /* side effects */ true);
+
+  object = Builder.CreateBitCast(object, VoidPtrTy);
+  EmitNounwindRuntimeCall(extender, object);
+}
+
+/// GenerateObjCAtomicSetterCopyHelperFunction - Given a c++ object type with
+/// non-trivial copy assignment function, produce following helper function.
+/// static void copyHelper(Ty *dest, const Ty *source) { *dest = *source; }
+///
+llvm::Constant *
+CodeGenFunction::GenerateObjCAtomicSetterCopyHelperFunction(
+                                        const ObjCPropertyImplDecl *PID) {
+  if (!getLangOpts().CPlusPlus ||
+      !getLangOpts().ObjCRuntime.hasAtomicCopyHelper())
+    return nullptr;
+  QualType Ty = PID->getPropertyIvarDecl()->getType();
+  if (!Ty->isRecordType())
+    return nullptr;
+  const ObjCPropertyDecl *PD = PID->getPropertyDecl();
+  if ((!(PD->getPropertyAttributes() & ObjCPropertyAttribute::kind_atomic)))
+    return nullptr;
+  llvm::Constant *HelperFn = nullptr;
+  if (hasTrivialSetExpr(PID))
+    return nullptr;
+  assert(PID->getSetterCXXAssignment() && "SetterCXXAssignment - null");
+  if ((HelperFn = CGM.getAtomicSetterHelperFnMap(Ty)))
+    return HelperFn;
+
+  ASTContext &C = getContext();
+  IdentifierInfo *II
+    = &CGM.getContext().Idents.get("__assign_helper_atomic_property_");
+
+  QualType ReturnTy = C.VoidTy;
+  QualType DestTy = C.getPointerType(Ty);
+  QualType SrcTy = Ty;
+  SrcTy.addConst();
+  SrcTy = C.getPointerType(SrcTy);
+
+  SmallVector<QualType, 2> ArgTys;
+  ArgTys.push_back(DestTy);
+  ArgTys.push_back(SrcTy);
+  QualType FunctionTy = C.getFunctionType(ReturnTy, ArgTys, {});
+
+  FunctionDecl *FD = FunctionDecl::Create(
+      C, C.getTranslationUnitDecl(), SourceLocation(), SourceLocation(), II,
+      FunctionTy, nullptr, SC_Static, false, false, false);
+
+  FunctionArgList args;
+  ParmVarDecl *Params[2];
+  ParmVarDecl *DstDecl = ParmVarDecl::Create(
+      C, FD, SourceLocation(), SourceLocation(), nullptr, DestTy,
+      C.getTrivialTypeSourceInfo(DestTy, SourceLocation()), SC_None,
+      /*DefArg=*/nullptr);
+  args.push_back(Params[0] = DstDecl);
+  ParmVarDecl *SrcDecl = ParmVarDecl::Create(
+      C, FD, SourceLocation(), SourceLocation(), nullptr, SrcTy,
+      C.getTrivialTypeSourceInfo(SrcTy, SourceLocation()), SC_None,
+      /*DefArg=*/nullptr);
+  args.push_back(Params[1] = SrcDecl);
+  FD->setParams(Params);
+
+  const CGFunctionInfo &FI =
+      CGM.getTypes().arrangeBuiltinFunctionDeclaration(ReturnTy, args);
+
+  llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
+
+  llvm::Function *Fn =
+    llvm::Function::Create(LTy, llvm::GlobalValue::InternalLinkage,
+                           "__assign_helper_atomic_property_",
+                           &CGM.getModule());
+
+  CGM.SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
+
+  StartFunction(FD, ReturnTy, Fn, FI, args);
+
+  DeclRefExpr DstExpr(C, DstDecl, false, DestTy, VK_PRValue, SourceLocation());
+  UnaryOperator *DST = UnaryOperator::Create(
+      C, &DstExpr, UO_Deref, DestTy->getPointeeType(), VK_LValue, OK_Ordinary,
+      SourceLocation(), false, FPOptionsOverride());
+
+  DeclRefExpr SrcExpr(C, SrcDecl, false, SrcTy, VK_PRValue, SourceLocation());
+  UnaryOperator *SRC = UnaryOperator::Create(
+      C, &SrcExpr, UO_Deref, SrcTy->getPointeeType(), VK_LValue, OK_Ordinary,
+      SourceLocation(), false, FPOptionsOverride());
+
+  Expr *Args[2] = {DST, SRC};
+  CallExpr *CalleeExp = cast<CallExpr>(PID->getSetterCXXAssignment());
+  CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
+      C, OO_Equal, CalleeExp->getCallee(), Args, DestTy->getPointeeType(),
+      VK_LValue, SourceLocation(), FPOptionsOverride());
+
+  EmitStmt(TheCall);
+
+  FinishFunction();
+  HelperFn = llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
+  CGM.setAtomicSetterHelperFnMap(Ty, HelperFn);
+  return HelperFn;
+}
+
+llvm::Constant *
+CodeGenFunction::GenerateObjCAtomicGetterCopyHelperFunction(
+                                            const ObjCPropertyImplDecl *PID) {
+  if (!getLangOpts().CPlusPlus ||
+      !getLangOpts().ObjCRuntime.hasAtomicCopyHelper())
+    return nullptr;
+  const ObjCPropertyDecl *PD = PID->getPropertyDecl();
+  QualType Ty = PD->getType();
+  if (!Ty->isRecordType())
+    return nullptr;
+  if ((!(PD->getPropertyAttributes() & ObjCPropertyAttribute::kind_atomic)))
+    return nullptr;
+  llvm::Constant *HelperFn = nullptr;
+  if (hasTrivialGetExpr(PID))
+    return nullptr;
+  assert(PID->getGetterCXXConstructor() && "getGetterCXXConstructor - null");
+  if ((HelperFn = CGM.getAtomicGetterHelperFnMap(Ty)))
+    return HelperFn;
+
+  ASTContext &C = getContext();
+  IdentifierInfo *II =
+      &CGM.getContext().Idents.get("__copy_helper_atomic_property_");
+
+  QualType ReturnTy = C.VoidTy;
+  QualType DestTy = C.getPointerType(Ty);
+  QualType SrcTy = Ty;
+  SrcTy.addConst();
+  SrcTy = C.getPointerType(SrcTy);
+
+  SmallVector<QualType, 2> ArgTys;
+  ArgTys.push_back(DestTy);
+  ArgTys.push_back(SrcTy);
+  QualType FunctionTy = C.getFunctionType(ReturnTy, ArgTys, {});
+
+  FunctionDecl *FD = FunctionDecl::Create(
+      C, C.getTranslationUnitDecl(), SourceLocation(), SourceLocation(), II,
+      FunctionTy, nullptr, SC_Static, false, false, false);
+
+  FunctionArgList args;
+  ParmVarDecl *Params[2];
+  ParmVarDecl *DstDecl = ParmVarDecl::Create(
+      C, FD, SourceLocation(), SourceLocation(), nullptr, DestTy,
+      C.getTrivialTypeSourceInfo(DestTy, SourceLocation()), SC_None,
+      /*DefArg=*/nullptr);
+  args.push_back(Params[0] = DstDecl);
+  ParmVarDecl *SrcDecl = ParmVarDecl::Create(
+      C, FD, SourceLocation(), SourceLocation(), nullptr, SrcTy,
+      C.getTrivialTypeSourceInfo(SrcTy, SourceLocation()), SC_None,
+      /*DefArg=*/nullptr);
+  args.push_back(Params[1] = SrcDecl);
+  FD->setParams(Params);
+
+  const CGFunctionInfo &FI =
+      CGM.getTypes().arrangeBuiltinFunctionDeclaration(ReturnTy, args);
+
+  llvm::FunctionType *LTy = CGM.getTypes().GetFunctionType(FI);
+
+  llvm::Function *Fn = llvm::Function::Create(
+      LTy, llvm::GlobalValue::InternalLinkage, "__copy_helper_atomic_property_",
+      &CGM.getModule());
+
+  CGM.SetInternalFunctionAttributes(GlobalDecl(), Fn, FI);
+
+  StartFunction(FD, ReturnTy, Fn, FI, args);
+
+  DeclRefExpr SrcExpr(getContext(), SrcDecl, false, SrcTy, VK_PRValue,
+                      SourceLocation());
+
+  UnaryOperator *SRC = UnaryOperator::Create(
+      C, &SrcExpr, UO_Deref, SrcTy->getPointeeType(), VK_LValue, OK_Ordinary,
+      SourceLocation(), false, FPOptionsOverride());
+
+  CXXConstructExpr *CXXConstExpr =
+    cast<CXXConstructExpr>(PID->getGetterCXXConstructor());
+
+  SmallVector<Expr*, 4> ConstructorArgs;
+  ConstructorArgs.push_back(SRC);
+  ConstructorArgs.append(std::next(CXXConstExpr->arg_begin()),
+                         CXXConstExpr->arg_end());
+
+  CXXConstructExpr *TheCXXConstructExpr =
+    CXXConstructExpr::Create(C, Ty, SourceLocation(),
+                             CXXConstExpr->getConstructor(),
+                             CXXConstExpr->isElidable(),
+                             ConstructorArgs,
+                             CXXConstExpr->hadMultipleCandidates(),
+                             CXXConstExpr->isListInitialization(),
+                             CXXConstExpr->isStdInitListInitialization(),
+                             CXXConstExpr->requiresZeroInitialization(),
+                             CXXConstExpr->getConstructionKind(),
+                             SourceRange());
+
+  DeclRefExpr DstExpr(getContext(), DstDecl, false, DestTy, VK_PRValue,
+                      SourceLocation());
+
+  RValue DV = EmitAnyExpr(&DstExpr);
+  CharUnits Alignment
+    = getContext().getTypeAlignInChars(TheCXXConstructExpr->getType());
+  EmitAggExpr(TheCXXConstructExpr,
+              AggValueSlot::forAddr(Address(DV.getScalarVal(), Alignment),
+                                    Qualifiers(),
+                                    AggValueSlot::IsDestructed,
+                                    AggValueSlot::DoesNotNeedGCBarriers,
+                                    AggValueSlot::IsNotAliased,
+                                    AggValueSlot::DoesNotOverlap));
+
+  FinishFunction();
+  HelperFn = llvm::ConstantExpr::getBitCast(Fn, VoidPtrTy);
+  CGM.setAtomicGetterHelperFnMap(Ty, HelperFn);
+  return HelperFn;
+}
+
+llvm::Value *
+CodeGenFunction::EmitBlockCopyAndAutorelease(llvm::Value *Block, QualType Ty) {
+  // Get selectors for retain/autorelease.
+  IdentifierInfo *CopyID = &getContext().Idents.get("copy");
+  Selector CopySelector =
+      getContext().Selectors.getNullarySelector(CopyID);
+  IdentifierInfo *AutoreleaseID = &getContext().Idents.get("autorelease");
+  Selector AutoreleaseSelector =
+      getContext().Selectors.getNullarySelector(AutoreleaseID);
+
+  // Emit calls to retain/autorelease.
+  CGObjCRuntime &Runtime = CGM.getObjCRuntime();
+  llvm::Value *Val = Block;
+  RValue Result;
+  Result = Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
+                                       Ty, CopySelector,
+                                       Val, CallArgList(), nullptr, nullptr);
+  Val = Result.getScalarVal();
+  Result = Runtime.GenerateMessageSend(*this, ReturnValueSlot(),
+                                       Ty, AutoreleaseSelector,
+                                       Val, CallArgList(), nullptr, nullptr);
+  Val = Result.getScalarVal();
+  return Val;
+}
+
+static unsigned getBaseMachOPlatformID(const llvm::Triple &TT) {
+  switch (TT.getOS()) {
+  case llvm::Triple::Darwin:
+  case llvm::Triple::MacOSX:
+    return llvm::MachO::PLATFORM_MACOS;
+  case llvm::Triple::IOS:
+    return llvm::MachO::PLATFORM_IOS;
+  case llvm::Triple::TvOS:
+    return llvm::MachO::PLATFORM_TVOS;
+  case llvm::Triple::WatchOS:
+    return llvm::MachO::PLATFORM_WATCHOS;
+  default:
+    return /*Unknown platform*/ 0;
+  }
+}
+
+static llvm::Value *emitIsPlatformVersionAtLeast(CodeGenFunction &CGF,
+                                                 const VersionTuple &Version) {
+  CodeGenModule &CGM = CGF.CGM;
+  // Note: we intend to support multi-platform version checks, so reserve
+  // the room for a dual platform checking invocation that will be
+  // implemented in the future.
+  llvm::SmallVector<llvm::Value *, 8> Args;
+
+  auto EmitArgs = [&](const VersionTuple &Version, const llvm::Triple &TT) {
+    Optional<unsigned> Min = Version.getMinor(), SMin = Version.getSubminor();
+    Args.push_back(
+        llvm::ConstantInt::get(CGM.Int32Ty, getBaseMachOPlatformID(TT)));
+    Args.push_back(llvm::ConstantInt::get(CGM.Int32Ty, Version.getMajor()));
+    Args.push_back(llvm::ConstantInt::get(CGM.Int32Ty, Min.getValueOr(0)));
+    Args.push_back(llvm::ConstantInt::get(CGM.Int32Ty, SMin.getValueOr(0)));
+  };
+
+  assert(!Version.empty() && "unexpected empty version");
+  EmitArgs(Version, CGM.getTarget().getTriple());
+
+  if (!CGM.IsPlatformVersionAtLeastFn) {
+    llvm::FunctionType *FTy = llvm::FunctionType::get(
+        CGM.Int32Ty, {CGM.Int32Ty, CGM.Int32Ty, CGM.Int32Ty, CGM.Int32Ty},
+        false);
+    CGM.IsPlatformVersionAtLeastFn =
+        CGM.CreateRuntimeFunction(FTy, "__isPlatformVersionAtLeast");
+  }
+
+  llvm::Value *Check =
+      CGF.EmitNounwindRuntimeCall(CGM.IsPlatformVersionAtLeastFn, Args);
+  return CGF.Builder.CreateICmpNE(Check,
+                                  llvm::Constant::getNullValue(CGM.Int32Ty));
+}
+
+llvm::Value *
+CodeGenFunction::EmitBuiltinAvailable(const VersionTuple &Version) {
+  // Darwin uses the new __isPlatformVersionAtLeast family of routines.
+  if (CGM.getTarget().getTriple().isOSDarwin())
+    return emitIsPlatformVersionAtLeast(*this, Version);
+
+  if (!CGM.IsOSVersionAtLeastFn) {
+    llvm::FunctionType *FTy =
+        llvm::FunctionType::get(Int32Ty, {Int32Ty, Int32Ty, Int32Ty}, false);
+    CGM.IsOSVersionAtLeastFn =
+        CGM.CreateRuntimeFunction(FTy, "__isOSVersionAtLeast");
+  }
+
+  Optional<unsigned> Min = Version.getMinor(), SMin = Version.getSubminor();
+  llvm::Value *Args[] = {
+      llvm::ConstantInt::get(CGM.Int32Ty, Version.getMajor()),
+      llvm::ConstantInt::get(CGM.Int32Ty, Min.getValueOr(0)),
+      llvm::ConstantInt::get(CGM.Int32Ty, SMin.getValueOr(0))
+  };
+
+  llvm::Value *CallRes =
+      EmitNounwindRuntimeCall(CGM.IsOSVersionAtLeastFn, Args);
+
+  return Builder.CreateICmpNE(CallRes, llvm::Constant::getNullValue(Int32Ty));
+}
+
+static bool isFoundationNeededForDarwinAvailabilityCheck(
+    const llvm::Triple &TT, const VersionTuple &TargetVersion) {
+  VersionTuple FoundationDroppedInVersion;
+  switch (TT.getOS()) {
+  case llvm::Triple::IOS:
+  case llvm::Triple::TvOS:
+    FoundationDroppedInVersion = VersionTuple(/*Major=*/13);
+    break;
+  case llvm::Triple::WatchOS:
+    FoundationDroppedInVersion = VersionTuple(/*Major=*/6);
+    break;
+  case llvm::Triple::Darwin:
+  case llvm::Triple::MacOSX:
+    FoundationDroppedInVersion = VersionTuple(/*Major=*/10, /*Minor=*/15);
+    break;
+  default:
+    llvm_unreachable("Unexpected OS");
+  }
+  return TargetVersion < FoundationDroppedInVersion;
+}
+
+void CodeGenModule::emitAtAvailableLinkGuard() {
+  if (!IsPlatformVersionAtLeastFn)
+    return;
+  // @available requires CoreFoundation only on Darwin.
+  if (!Target.getTriple().isOSDarwin())
+    return;
+  // @available doesn't need Foundation on macOS 10.15+, iOS/tvOS 13+, or
+  // watchOS 6+.
+  if (!isFoundationNeededForDarwinAvailabilityCheck(
+          Target.getTriple(), Target.getPlatformMinVersion()))
+    return;
+  // Add -framework CoreFoundation to the linker commands. We still want to
+  // emit the core foundation reference down below because otherwise if
+  // CoreFoundation is not used in the code, the linker won't link the
+  // framework.
+  auto &Context = getLLVMContext();
+  llvm::Metadata *Args[2] = {llvm::MDString::get(Context, "-framework"),
+                             llvm::MDString::get(Context, "CoreFoundation")};
+  LinkerOptionsMetadata.push_back(llvm::MDNode::get(Context, Args));
+  // Emit a reference to a symbol from CoreFoundation to ensure that
+  // CoreFoundation is linked into the final binary.
+  llvm::FunctionType *FTy =
+      llvm::FunctionType::get(Int32Ty, {VoidPtrTy}, false);
+  llvm::FunctionCallee CFFunc =
+      CreateRuntimeFunction(FTy, "CFBundleGetVersionNumber");
+
+  llvm::FunctionType *CheckFTy = llvm::FunctionType::get(VoidTy, {}, false);
+  llvm::FunctionCallee CFLinkCheckFuncRef = CreateRuntimeFunction(
+      CheckFTy, "__clang_at_available_requires_core_foundation_framework",
+      llvm::AttributeList(), /*Local=*/true);
+  llvm::Function *CFLinkCheckFunc =
+      cast<llvm::Function>(CFLinkCheckFuncRef.getCallee()->stripPointerCasts());
+  if (CFLinkCheckFunc->empty()) {
+    CFLinkCheckFunc->setLinkage(llvm::GlobalValue::LinkOnceAnyLinkage);
+    CFLinkCheckFunc->setVisibility(llvm::GlobalValue::HiddenVisibility);
+    CodeGenFunction CGF(*this);
+    CGF.Builder.SetInsertPoint(CGF.createBasicBlock("", CFLinkCheckFunc));
+    CGF.EmitNounwindRuntimeCall(CFFunc,
+                                llvm::Constant::getNullValue(VoidPtrTy));
+    CGF.Builder.CreateUnreachable();
+    addCompilerUsedGlobal(CFLinkCheckFunc);
+  }
+}
+
+CGObjCRuntime::~CGObjCRuntime() {}