[ObjC] Allow declaring __weak pointer fields in C structs in ObjC-ARC

[ahatanak]

Summary

This patch makes changes that are needed to allow __weak fields in C structs when ARC is enabled.

[rjmccall]

include/clang/AST/Decl.h

3631 ↗

(On Diff #137009)

I feel like this flag should be set by Sema for C++ types that have to be passed indirectly as well; it can then become the single point of truth for that information.

lib/CodeGen/CGNonTrivialStruct.cpp

764 ↗

(On Diff #137009)

I guess this is the most reasonable thing to do, given that we don't have an entrypoint for it. Please ask the ObjC runtime team to consider giving us one, though. We could pretty easily peephole assignments into __weak variables where the source is loaded from a __weak l-value / x-value, and Swift would probably be able to take advantage of it, too.

You might want to go ahead and add emitARCCopyAssignWeak / emitARCMoveAssignWeak methods on CGF that do these operations and which can be optimized to use those entrypoints if/when they're added.

lib/CodeGen/TargetInfo.cpp

1326 ↗

(On Diff #137009)

Can we combine this into a single function that covers both the C++ case and this new one? Otherwise it seems likely that individual targets over time will only add one or the other.

[ahatanak]

Address review comments.

[ahatanak]

include/clang/AST/Decl.h

3631 ↗

(On Diff #137009)

I moved CXXRecordDecl::CanPassInRegisters to RecordDecl along with its setter and getter functions.

lib/CodeGen/CGNonTrivialStruct.cpp

764 ↗

(On Diff #137009)

Do you mean we should ask for the following objc runtime functions and use them in visitARCWeak?

// dst and src are either null or registered as __weak objects.
void objc_copyAssignWeak(id *dst, id *src)
void objc_moveAssignWeak(id *dst, id *src)
`

lib/CodeGen/TargetInfo.cpp

1326 ↗

(On Diff #137009)

I added another definition of classifyReturnType and taught getRecordArgABI to detect non-trivial C structs. Currently, x86, arm, and arm64 are the only targets that use the new overload of classifyReturnType. I can modify the other targets to use it too if that is desirable.

[rjmccall]

LGTM, thanks.

lib/CodeGen/CGNonTrivialStruct.cpp

764 ↗

(On Diff #137009)

I meant that we should implement emitARCCopyAssignWeak and emitARCMoveAssignWeak by calling those functions if they're available, yes.

(Obviously that would be a follow-up patch, even assuming the ObjC runtime agrees to add them.)

Those functions would be specified as leaving the source in a zeroed state, which is as good as uninitialized, so they could be used for true-destructive moves as well.

[ahatanak]

This was reverted in r327294 because it caused module-enabled builders to fail after I moved CXXRecordDecl::CanPassInRegisters to RecordDecl. I'm recommitting this patch with fixes to ASTDeclReader and ASTWriter.

cfe/trunk/include/clang/AST/Decl.h

class RecordDecl : public TagDecl {
   /// when needed.
   mutable bool LoadedFieldsFromExternalStorage : 1;
 
   /// Basic properties of non-trivial C structs.
   bool NonTrivialToPrimitiveDefaultInitialize : 1;
   bool NonTrivialToPrimitiveCopy : 1;
   bool NonTrivialToPrimitiveDestroy : 1;
 
+  /// True if this class can be passed in a non-address-preserving fashion
+  /// (such as in registers).
+  /// This does not imply anything about how the ABI in use will actually
+  /// pass an object of this class.
+  bool CanPassInRegisters : 1;
+
 protected:
   RecordDecl(Kind DK, TagKind TK, const ASTContext &C, DeclContext *DC,
              SourceLocation StartLoc, SourceLocation IdLoc,
              IdentifierInfo *Id, RecordDecl *PrevDecl);
 
 public:
   static RecordDecl *Create(const ASTContext &C, TagKind TK, DeclContext *DC,
                             SourceLocation StartLoc, SourceLocation IdLoc,
public:
   bool isNonTrivialToPrimitiveDestroy() const {
     return NonTrivialToPrimitiveDestroy;
   }
 
   void setNonTrivialToPrimitiveDestroy() {
     NonTrivialToPrimitiveDestroy = true;
   }
 
+  /// Determine whether this class can be passed in registers. In C++ mode,
+  /// it must have at least one trivial, non-deleted copy or move constructor.
+  /// FIXME: This should be set as part of completeDefinition.
+  bool canPassInRegisters() const {
+    return CanPassInRegisters;
+  }
+
+  /// Set that we can pass this RecordDecl in registers.
+  void setCanPassInRegisters(bool CanPass) {
+    CanPassInRegisters = CanPass;
+  }
+
   /// \brief Determines whether this declaration represents the
   /// injected class name.
   ///
   /// The injected class name in C++ is the name of the class that
   /// appears inside the class itself. For example:
   ///
   /// \code
   /// struct C {

cfe/trunk/include/clang/AST/DeclCXX.h

struct DefinitionData {
     /// \brief True when this class has at least one user-declared constexpr
     /// constructor which is neither the copy nor move constructor.
     unsigned HasConstexprNonCopyMoveConstructor : 1;
 
     /// \brief True if this class has a (possibly implicit) defaulted default
     /// constructor.
     unsigned HasDefaultedDefaultConstructor : 1;
 
-    /// \brief True if this class can be passed in a non-address-preserving
-    /// fashion (such as in registers) according to the C++ language rules.
-    /// This does not imply anything about how the ABI in use will actually
-    /// pass an object of this class.
-    unsigned CanPassInRegisters : 1;
-
     /// \brief True if a defaulted default constructor for this class would
     /// be constexpr.
     unsigned DefaultedDefaultConstructorIsConstexpr : 1;
 
     /// \brief True if this class has a constexpr default constructor.
     ///
     /// This is true for either a user-declared constexpr default constructor
     /// or an implicitly declared constexpr default constructor.
public:
   /// semantic effect.
   ///
   /// Any such destructor will be trivial, public, defaulted and not deleted,
   /// and will call only irrelevant destructors.
   bool hasIrrelevantDestructor() const {
     return data().HasIrrelevantDestructor;
   }
 
-  /// \brief Determine whether this class has at least one trivial, non-deleted
-  /// copy or move constructor.
-  bool canPassInRegisters() const {
-    return data().CanPassInRegisters;
-  }
-
-  /// \brief Set that we can pass this RecordDecl in registers.
-  // FIXME: This should be set as part of completeDefinition.
-  void setCanPassInRegisters(bool CanPass) {
-    data().CanPassInRegisters = CanPass;
-  }
-
   /// Determine whether the triviality for the purpose of calls for this class
   /// is overridden to be trivial because this class or the type of one of its
   /// subobjects has attribute "trivial_abi".
   bool hasTrivialABIOverride() const {
     return canPassInRegisters() && hasNonTrivialDestructor();
   }
 
   /// \brief Determine whether this class has a non-literal or/ volatile type

cfe/trunk/include/clang/AST/Type.h

enum PrimitiveDefaultInitializeKind {
     /// this case is zero-valued so that values of this enum can be used as a
     /// boolean condition for non-triviality.
     PDIK_Trivial,
 
     /// The type is an Objective-C retainable pointer type that is qualified
     /// with the ARC __strong qualifier.
     PDIK_ARCStrong,
 
+    /// The type is an Objective-C retainable pointer type that is qualified
+    /// with the ARC __weak qualifier.
+    PDIK_ARCWeak,
+
     /// The type is a struct containing a field whose type is not PCK_Trivial.
     PDIK_Struct
   };
 
   /// Functions to query basic properties of non-trivial C struct types.
 
   /// Check if this is a non-trivial type that would cause a C struct
   /// transitively containing this type to be non-trivial to default initialize
enum PrimitiveCopyKind {
     /// that fall into one of the other non-trivial cases may additionally be
     /// volatile-qualified.
     PCK_VolatileTrivial,
 
     /// The type is an Objective-C retainable pointer type that is qualified
     /// with the ARC __strong qualifier.
     PCK_ARCStrong,
 
+    /// The type is an Objective-C retainable pointer type that is qualified
+    /// with the ARC __weak qualifier.
+    PCK_ARCWeak,
+
     /// The type is a struct containing a field whose type is neither
     /// PCK_Trivial nor PCK_VolatileTrivial.
     /// Note that a C++ struct type does not necessarily match this; C++ copying
     /// semantics are too complex to express here, in part because they depend
     /// on the exact constructor or assignment operator that is chosen by
     /// overload resolution to do the copy.
     PCK_Struct
   };
 
   /// Check if this is a non-trivial type that would cause a C struct
   /// transitively containing this type to be non-trivial to copy and return the
   /// kind.
   PrimitiveCopyKind isNonTrivialToPrimitiveCopy() const;
 
   /// Check if this is a non-trivial type that would cause a C struct
   /// transitively containing this type to be non-trivial to destructively
   /// move and return the kind. Destructive move in this context is a C++-style
   /// move in which the source object is placed in a valid but unspecified state
   /// after it is moved, as opposed to a truly destructive move in which the
   /// source object is placed in an uninitialized state.
   PrimitiveCopyKind isNonTrivialToPrimitiveDestructiveMove() const;
 
+  bool canPassInRegisters() const;
+
   enum DestructionKind {
     DK_none,
     DK_cxx_destructor,
     DK_objc_strong_lifetime,
     DK_objc_weak_lifetime,
     DK_nontrivial_c_struct
   };
 

cfe/trunk/lib/AST/ASTImporter.cpp

ToData.DefaultedMoveAssignmentIsDeleted
       = FromData.DefaultedMoveAssignmentIsDeleted;
     ToData.DefaultedDestructorIsDeleted = FromData.DefaultedDestructorIsDeleted;
     ToData.HasTrivialSpecialMembers = FromData.HasTrivialSpecialMembers;
     ToData.HasIrrelevantDestructor = FromData.HasIrrelevantDestructor;
     ToData.HasConstexprNonCopyMoveConstructor
       = FromData.HasConstexprNonCopyMoveConstructor;
     ToData.HasDefaultedDefaultConstructor
       = FromData.HasDefaultedDefaultConstructor;
-    ToData.CanPassInRegisters = FromData.CanPassInRegisters;
     ToData.DefaultedDefaultConstructorIsConstexpr
       = FromData.DefaultedDefaultConstructorIsConstexpr;
     ToData.HasConstexprDefaultConstructor
       = FromData.HasConstexprDefaultConstructor;
     ToData.HasNonLiteralTypeFieldsOrBases
       = FromData.HasNonLiteralTypeFieldsOrBases;
     // ComputedVisibleConversions not imported.
     ToData.UserProvidedDefaultConstructor

cfe/trunk/lib/AST/Decl.cpp

RecordDecl::RecordDecl(Kind DK, TagKind TK, const ASTContext &C,
                        DeclContext *DC, SourceLocation StartLoc,
                        SourceLocation IdLoc, IdentifierInfo *Id,
                        RecordDecl *PrevDecl)
     : TagDecl(DK, TK, C, DC, IdLoc, Id, PrevDecl, StartLoc),
       HasFlexibleArrayMember(false), AnonymousStructOrUnion(false),
       HasObjectMember(false), HasVolatileMember(false),
       LoadedFieldsFromExternalStorage(false),
       NonTrivialToPrimitiveDefaultInitialize(false),
-      NonTrivialToPrimitiveCopy(false), NonTrivialToPrimitiveDestroy(false) {
+      NonTrivialToPrimitiveCopy(false), NonTrivialToPrimitiveDestroy(false),
+      CanPassInRegisters(true) {
   assert(classof(static_cast<Decl*>(this)) && "Invalid Kind!");
 }
 
 RecordDecl *RecordDecl::Create(const ASTContext &C, TagKind TK, DeclContext *DC,
                                SourceLocation StartLoc, SourceLocation IdLoc,
                                IdentifierInfo *Id, RecordDecl* PrevDecl) {
   RecordDecl *R = new (C, DC) RecordDecl(Record, TK, C, DC,
                                          StartLoc, IdLoc, Id, PrevDecl);

cfe/trunk/lib/AST/DeclCXX.cpp

: UserDeclaredConstructor(false), UserDeclaredSpecialMembers(0),
       DefaultedMoveConstructorIsDeleted(false),
       DefaultedMoveAssignmentIsDeleted(false),
       DefaultedDestructorIsDeleted(false), HasTrivialSpecialMembers(SMF_All),
       HasTrivialSpecialMembersForCall(SMF_All),
       DeclaredNonTrivialSpecialMembers(0),
       DeclaredNonTrivialSpecialMembersForCall(0), HasIrrelevantDestructor(true),
       HasConstexprNonCopyMoveConstructor(false),
       HasDefaultedDefaultConstructor(false),
-      CanPassInRegisters(true),
       DefaultedDefaultConstructorIsConstexpr(true),
       HasConstexprDefaultConstructor(false),
       HasNonLiteralTypeFieldsOrBases(false), ComputedVisibleConversions(false),
       UserProvidedDefaultConstructor(false), DeclaredSpecialMembers(0),
       ImplicitCopyConstructorCanHaveConstParamForVBase(true),
       ImplicitCopyConstructorCanHaveConstParamForNonVBase(true),
       ImplicitCopyAssignmentHasConstParam(true),
       HasDeclaredCopyConstructorWithConstParam(false),

cfe/trunk/lib/AST/Type.cpp

 
 QualType::PrimitiveDefaultInitializeKind
 QualType::isNonTrivialToPrimitiveDefaultInitialize() const {
   if (const auto *RT =
           getTypePtr()->getBaseElementTypeUnsafe()->getAs<RecordType>())
     if (RT->getDecl()->isNonTrivialToPrimitiveDefaultInitialize())
       return PDIK_Struct;
 
-  Qualifiers::ObjCLifetime Lifetime = getQualifiers().getObjCLifetime();
-  if (Lifetime == Qualifiers::OCL_Strong)
+  switch (getQualifiers().getObjCLifetime()) {
+  case Qualifiers::OCL_Strong:
     return PDIK_ARCStrong;
-
+  case Qualifiers::OCL_Weak:
+    return PDIK_ARCWeak;
+  default:
     return PDIK_Trivial;
   }
+}
 
 QualType::PrimitiveCopyKind QualType::isNonTrivialToPrimitiveCopy() const {
   if (const auto *RT =
           getTypePtr()->getBaseElementTypeUnsafe()->getAs<RecordType>())
     if (RT->getDecl()->isNonTrivialToPrimitiveCopy())
       return PCK_Struct;
 
   Qualifiers Qs = getQualifiers();
-  if (Qs.getObjCLifetime() == Qualifiers::OCL_Strong)
+  switch (Qs.getObjCLifetime()) {
+  case Qualifiers::OCL_Strong:
     return PCK_ARCStrong;
-
+  case Qualifiers::OCL_Weak:
+    return PCK_ARCWeak;
+  default:
     return Qs.hasVolatile() ? PCK_VolatileTrivial : PCK_Trivial;
   }
+}
 
 QualType::PrimitiveCopyKind
 QualType::isNonTrivialToPrimitiveDestructiveMove() const {
   return isNonTrivialToPrimitiveCopy();
 }
 
+bool QualType::canPassInRegisters() const {
+  if (const auto *RT =
+          getTypePtr()->getBaseElementTypeUnsafe()->getAs<RecordType>())
+    return RT->getDecl()->canPassInRegisters();
+
+  if (getQualifiers().getObjCLifetime() == Qualifiers::OCL_Weak)
+    return false;
+
+  return true;
+}
+
 bool Type::isLiteralType(const ASTContext &Ctx) const {
   if (isDependentType())
     return false;
 
   // C++1y [basic.types]p10:
   //   A type is a literal type if it is:
   //   -- cv void; or
   if (Ctx.getLangOpts().CPlusPlus14 && isVoidType())

cfe/trunk/lib/CodeGen/CGBlocks.cpp

computeCopyInfoForBlockCapture(const BlockDecl::Capture &CI, QualType T,
   bool isBlockPointer = T->isBlockPointerType();
   if (isBlockPointer)
     Flags = BLOCK_FIELD_IS_BLOCK;
 
   switch (T.isNonTrivialToPrimitiveCopy()) {
   case QualType::PCK_Struct:
     return std::make_pair(BlockCaptureEntityKind::NonTrivialCStruct,
                           BlockFieldFlags());
+  case QualType::PCK_ARCWeak:
+    // We need to register __weak direct captures with the runtime.
+    return std::make_pair(BlockCaptureEntityKind::ARCWeak, Flags);
   case QualType::PCK_ARCStrong:
     // We need to retain the copied value for __strong direct captures.
     // If it's a block pointer, we have to copy the block and assign that to
     // the destination pointer, so we might as well use _Block_object_assign.
     // Otherwise we can avoid that.
     return std::make_pair(!isBlockPointer ? BlockCaptureEntityKind::ARCStrong
                                           : BlockCaptureEntityKind::BlockObject,
                           Flags);
   case QualType::PCK_Trivial:
   case QualType::PCK_VolatileTrivial: {
     if (!T->isObjCRetainableType())
       // For all other types, the memcpy is fine.
       return std::make_pair(BlockCaptureEntityKind::None, BlockFieldFlags());
 
     // Special rules for ARC captures:
     Qualifiers QS = T.getQualifiers();
 
-    // We need to register __weak direct captures with the runtime.
-    if (QS.getObjCLifetime() == Qualifiers::OCL_Weak)
-      return std::make_pair(BlockCaptureEntityKind::ARCWeak, Flags);
-
     // Non-ARC captures of retainable pointers are strong and
     // therefore require a call to _Block_object_assign.
     if (!QS.getObjCLifetime() && !LangOpts.ObjCAutoRefCount)
       return std::make_pair(BlockCaptureEntityKind::BlockObject, Flags);
 
     // Otherwise the memcpy is fine.
     return std::make_pair(BlockCaptureEntityKind::None, BlockFieldFlags());
   }

cfe/trunk/lib/CodeGen/CGNonTrivialStruct.cpp

struct DefaultInitializedTypeVisitor {
   RetTy visit(QualType::PrimitiveDefaultInitializeKind PDIK, QualType FT,
               Ts &&... Args) {
     if (asDerived().getContext().getAsArrayType(FT))
       return asDerived().visitArray(PDIK, FT, std::forward<Ts>(Args)...);
 
     switch (PDIK) {
     case QualType::PDIK_ARCStrong:
       return asDerived().visitARCStrong(FT, std::forward<Ts>(Args)...);
+    case QualType::PDIK_ARCWeak:
+      return asDerived().visitARCWeak(FT, std::forward<Ts>(Args)...);
     case QualType::PDIK_Struct:
       return asDerived().visitStruct(FT, std::forward<Ts>(Args)...);
     case QualType::PDIK_Trivial:
       return asDerived().visitTrivial(FT, std::forward<Ts>(Args)...);
     }
 
     llvm_unreachable("unknown default-initialize kind");
   }
RetTy visit(QualType::PrimitiveCopyKind PCK, QualType FT, Ts &&... Args) {
     asDerived().preVisit(PCK, FT, std::forward<Ts>(Args)...);
 
     if (asDerived().getContext().getAsArrayType(FT))
       return asDerived().visitArray(PCK, FT, std::forward<Ts>(Args)...);
 
     switch (PCK) {
     case QualType::PCK_ARCStrong:
       return asDerived().visitARCStrong(FT, std::forward<Ts>(Args)...);
+    case QualType::PCK_ARCWeak:
+      return asDerived().visitARCWeak(FT, std::forward<Ts>(Args)...);
     case QualType::PCK_Struct:
       return asDerived().visitStruct(FT, std::forward<Ts>(Args)...);
     case QualType::PCK_Trivial:
       return asDerived().visitTrivial(FT, std::forward<Ts>(Args)...);
     case QualType::PCK_VolatileTrivial:
       return asDerived().visitVolatileTrivial(FT, std::forward<Ts>(Args)...);
     }
 
for (const FieldDecl *FD : RD->fields()) {
       asDerived().visit(FT, FD, CurStructOffset, Args...);
     }
 
     asDerived().flushTrivialFields(Args...);
   }
 
   template <class... Ts> void visitTrivial(Ts... Args) {}
 
-  template <class... Ts> void visitARCWeak(Ts... Args) {
-    // FIXME: remove this when visitARCWeak is implemented in the subclasses.
-    llvm_unreachable("weak field is not expected");
-  }
-
   template <class... Ts> void visitCXXDestructor(Ts... Args) {
     llvm_unreachable("field of a C++ struct type is not expected");
   }
 
   template <class... Ts> void flushTrivialFields(Ts... Args) {}
 
   uint64_t getFieldOffsetInBits(const FieldDecl *FD) {
     return FD ? Ctx.getASTRecordLayout(FD->getParent())
void visitARCStrong(QualType FT, const FieldDecl *FD,
                       CharUnits CurStructOffset) {
     appendStr("_s");
     if (FT->isBlockPointerType())
       appendStr("b");
     CharUnits FieldOffset = CurStructOffset + asDerived().getFieldOffset(FD);
     appendStr(getVolatileOffsetStr(FT.isVolatileQualified(), FieldOffset));
   }
 
+  void visitARCWeak(QualType FT, const FieldDecl *FD,
+                    CharUnits CurStructOffset) {
+    appendStr("_w");
+    CharUnits FieldOffset = CurStructOffset + asDerived().getFieldOffset(FD);
+    appendStr(getVolatileOffsetStr(FT.isVolatileQualified(), FieldOffset));
+  }
+
   void visitStruct(QualType QT, const FieldDecl *FD,
                    CharUnits CurStructOffset) {
     CharUnits FieldOffset = CurStructOffset + asDerived().getFieldOffset(FD);
     asDerived().visitStructFields(QT, FieldOffset);
   }
 
   template <class FieldKind>
   void visitArray(FieldKind FK, QualType QT, const FieldDecl *FD,
struct GenDestructor : StructVisitor<GenDestructor>,
                        DestructedTypeVisitor<GenDestructor> {
   GenDestructor(ASTContext &Ctx) : StructVisitor<GenDestructor>(Ctx) {}
   void visitARCStrong(QualType QT, const FieldDecl *FD,
                       CharUnits CurStackOffset, std::array<Address, 1> Addrs) {
     CGF->destroyARCStrongImprecise(
         *CGF, getAddrWithOffset(Addrs[DstIdx], CurStackOffset, FD), QT);
   }
 
+  void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStackOffset,
+                    std::array<Address, 1> Addrs) {
+    CGF->destroyARCWeak(
+        *CGF, getAddrWithOffset(Addrs[DstIdx], CurStackOffset, FD), QT);
+  }
+
   void callSpecialFunction(QualType FT, CharUnits Offset,
                            std::array<Address, 1> Addrs) {
     CGF->callCStructDestructor(
         CGF->MakeAddrLValue(getAddrWithOffset(Addrs[DstIdx], Offset), FT));
   }
 };
 
 struct GenDefaultInitialize
     : StructVisitor<GenDefaultInitialize>,
       GenFuncBase<GenDefaultInitialize>,
       DefaultInitializedTypeVisitor<GenDefaultInitialize> {
   typedef GenFuncBase<GenDefaultInitialize> GenFuncBaseTy;
   GenDefaultInitialize(ASTContext &Ctx)
       : StructVisitor<GenDefaultInitialize>(Ctx) {}
 
   void visitARCStrong(QualType QT, const FieldDecl *FD,
                       CharUnits CurStackOffset, std::array<Address, 1> Addrs) {
     CGF->EmitNullInitialization(
         getAddrWithOffset(Addrs[DstIdx], CurStackOffset, FD), QT);
   }
 
+  void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStackOffset,
+                    std::array<Address, 1> Addrs) {
+    CGF->EmitNullInitialization(
+        getAddrWithOffset(Addrs[DstIdx], CurStackOffset, FD), QT);
+  }
+
   template <class FieldKind, size_t... Is>
   void visitArray(FieldKind FK, QualType QT, const FieldDecl *FD,
                   CharUnits CurStackOffset, std::array<Address, 1> Addrs) {
     if (!FK)
       return visitTrivial(QT, FD, CurStackOffset, Addrs);
 
     ASTContext &Ctx = getContext();
     CharUnits Size = Ctx.getTypeSizeInChars(QT);
void visitARCStrong(QualType QT, const FieldDecl *FD,
                       CharUnits CurStackOffset, std::array<Address, 2> Addrs) {
     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStackOffset, FD);
     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStackOffset, FD);
     llvm::Value *SrcVal = CGF->EmitLoadOfScalar(
         Addrs[SrcIdx], QT.isVolatileQualified(), QT, SourceLocation());
     llvm::Value *Val = CGF->EmitARCRetain(QT, SrcVal);
     CGF->EmitStoreOfScalar(Val, CGF->MakeAddrLValue(Addrs[DstIdx], QT), true);
   }
+
+  void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStackOffset,
+                    std::array<Address, 2> Addrs) {
+    Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStackOffset, FD);
+    Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStackOffset, FD);
+    CGF->EmitARCCopyWeak(Addrs[DstIdx], Addrs[SrcIdx]);
+  }
+
   void callSpecialFunction(QualType FT, CharUnits Offset,
                            std::array<Address, 2> Addrs) {
     CGF->callCStructCopyConstructor(CGF->MakeAddrLValue(Addrs[DstIdx], FT),
                                     CGF->MakeAddrLValue(Addrs[SrcIdx], FT));
   }
 };
 
 struct GenMoveConstructor : GenBinaryFunc<GenMoveConstructor, true> {
   GenMoveConstructor(ASTContext &Ctx)
       : GenBinaryFunc<GenMoveConstructor, true>(Ctx) {}
 
   void visitARCStrong(QualType QT, const FieldDecl *FD,
                       CharUnits CurStackOffset, std::array<Address, 2> Addrs) {
     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStackOffset, FD);
     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStackOffset, FD);
     LValue SrcLV = CGF->MakeAddrLValue(Addrs[SrcIdx], QT);
     llvm::Value *SrcVal =
         CGF->EmitLoadOfLValue(SrcLV, SourceLocation()).getScalarVal();
     CGF->EmitStoreOfScalar(getNullForVariable(SrcLV.getAddress()), SrcLV);
     CGF->EmitStoreOfScalar(SrcVal, CGF->MakeAddrLValue(Addrs[DstIdx], QT),
                            /* isInitialization */ true);
   }
+
+  void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStackOffset,
+                    std::array<Address, 2> Addrs) {
+    Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStackOffset, FD);
+    Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStackOffset, FD);
+    CGF->EmitARCMoveWeak(Addrs[DstIdx], Addrs[SrcIdx]);
+  }
+
   void callSpecialFunction(QualType FT, CharUnits Offset,
                            std::array<Address, 2> Addrs) {
     CGF->callCStructMoveConstructor(CGF->MakeAddrLValue(Addrs[DstIdx], FT),
                                     CGF->MakeAddrLValue(Addrs[SrcIdx], FT));
   }
 };
 
 struct GenCopyAssignment : GenBinaryFunc<GenCopyAssignment, false> {
   GenCopyAssignment(ASTContext &Ctx)
       : GenBinaryFunc<GenCopyAssignment, false>(Ctx) {}
 
   void visitARCStrong(QualType QT, const FieldDecl *FD,
                       CharUnits CurStackOffset, std::array<Address, 2> Addrs) {
     Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStackOffset, FD);
     Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStackOffset, FD);
     llvm::Value *SrcVal = CGF->EmitLoadOfScalar(
         Addrs[SrcIdx], QT.isVolatileQualified(), QT, SourceLocation());
     CGF->EmitARCStoreStrong(CGF->MakeAddrLValue(Addrs[DstIdx], QT), SrcVal,
                             false);
   }
+
+  void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStackOffset,
+                    std::array<Address, 2> Addrs) {
+    Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStackOffset, FD);
+    Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStackOffset, FD);
+    CGF->emitARCCopyAssignWeak(QT, Addrs[DstIdx], Addrs[SrcIdx]);
+  }
+
   void callSpecialFunction(QualType FT, CharUnits Offset,
                            std::array<Address, 2> Addrs) {
     CGF->callCStructCopyAssignmentOperator(
         CGF->MakeAddrLValue(Addrs[DstIdx], FT),
         CGF->MakeAddrLValue(Addrs[SrcIdx], FT));
   }
 };
 
void visitARCStrong(QualType QT, const FieldDecl *FD,
     CGF->EmitStoreOfScalar(getNullForVariable(SrcLV.getAddress()), SrcLV);
     LValue DstLV = CGF->MakeAddrLValue(Addrs[DstIdx], QT);
     llvm::Value *DstVal =
         CGF->EmitLoadOfLValue(DstLV, SourceLocation()).getScalarVal();
     CGF->EmitStoreOfScalar(SrcVal, DstLV);
     CGF->EmitARCRelease(DstVal, ARCImpreciseLifetime);
   }
 
+  void visitARCWeak(QualType QT, const FieldDecl *FD, CharUnits CurStackOffset,
+                    std::array<Address, 2> Addrs) {
+    Addrs[DstIdx] = getAddrWithOffset(Addrs[DstIdx], CurStackOffset, FD);
+    Addrs[SrcIdx] = getAddrWithOffset(Addrs[SrcIdx], CurStackOffset, FD);
+    CGF->emitARCMoveAssignWeak(QT, Addrs[DstIdx], Addrs[SrcIdx]);
+  }
+
   void callSpecialFunction(QualType FT, CharUnits Offset,
                            std::array<Address, 2> Addrs) {
     CGF->callCStructMoveAssignmentOperator(
         CGF->MakeAddrLValue(Addrs[DstIdx], FT),
         CGF->MakeAddrLValue(Addrs[SrcIdx], FT));
   }
 };
 

cfe/trunk/lib/CodeGen/CGObjC.cpp

 /// 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,
                        "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::Constant *&fn = CGM.getObjCEntrypoints().objc_autoreleasePoolPush;
   if (!fn) {
     llvm::FunctionType *fnType =
       llvm::FunctionType::get(Int8PtrTy, false);
     fn = createARCRuntimeFunction(CGM, fnType, "objc_autoreleasePoolPush");

cfe/trunk/lib/CodeGen/CodeGenFunction.h

public:
   }
 
   // ARC primitives.
   void EmitARCInitWeak(Address addr, llvm::Value *value);
   void EmitARCDestroyWeak(Address addr);
   llvm::Value *EmitARCLoadWeak(Address addr);
   llvm::Value *EmitARCLoadWeakRetained(Address addr);
   llvm::Value *EmitARCStoreWeak(Address addr, llvm::Value *value, bool ignored);
+  void emitARCCopyAssignWeak(QualType Ty, Address DstAddr, Address SrcAddr);
+  void emitARCMoveAssignWeak(QualType Ty, Address DstAddr, Address SrcAddr);
   void EmitARCCopyWeak(Address dst, Address src);
   void EmitARCMoveWeak(Address dst, Address src);
   llvm::Value *EmitARCRetainAutorelease(QualType type, llvm::Value *value);
   llvm::Value *EmitARCRetainAutoreleaseNonBlock(llvm::Value *value);
   llvm::Value *EmitARCStoreStrong(LValue lvalue, llvm::Value *value,
                                   bool resultIgnored);
   llvm::Value *EmitARCStoreStrongCall(Address addr, llvm::Value *value,
                                       bool resultIgnored);

cfe/trunk/lib/CodeGen/TargetInfo.cpp

bool SwiftABIInfo::isLegalVectorTypeForSwift(CharUnits vectorSize,
   // The default implementation of this assumes that the target guarantees
   // 128-bit SIMD support but nothing more.
   return (vectorSize.getQuantity() > 8 && vectorSize.getQuantity() <= 16);
 }
 
 static CGCXXABI::RecordArgABI getRecordArgABI(const RecordType *RT,
                                               CGCXXABI &CXXABI) {
   const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
-  if (!RD)
+  if (!RD) {
+    if (!RT->getDecl()->canPassInRegisters())
+      return CGCXXABI::RAA_Indirect;
     return CGCXXABI::RAA_Default;
+  }
   return CXXABI.getRecordArgABI(RD);
 }
 
 static CGCXXABI::RecordArgABI getRecordArgABI(QualType T,
                                               CGCXXABI &CXXABI) {
   const RecordType *RT = T->getAs<RecordType>();
   if (!RT)
     return CGCXXABI::RAA_Default;
   return getRecordArgABI(RT, CXXABI);
 }
 
+static bool classifyReturnType(const CGCXXABI &CXXABI, CGFunctionInfo &FI,
+                               const ABIInfo &Info) {
+  QualType Ty = FI.getReturnType();
+
+  if (const auto *RT = Ty->getAs<RecordType>())
+    if (!isa<CXXRecordDecl>(RT->getDecl()) &&
+        !RT->getDecl()->canPassInRegisters()) {
+      FI.getReturnInfo() = Info.getNaturalAlignIndirect(Ty);
+      return true;
+    }
+
+  return CXXABI.classifyReturnType(FI);
+}
+
 /// Pass transparent unions as if they were the type of the first element. Sema
 /// should ensure that all elements of the union have the same "machine type".
 static QualType useFirstFieldIfTransparentUnion(QualType Ty) {
   if (const RecordType *UT = Ty->getAsUnionType()) {
     const RecordDecl *UD = UT->getDecl();
     if (UD->hasAttr<TransparentUnionAttr>()) {
       assert(!UD->field_empty() && "sema created an empty transparent union");
       return UD->field_begin()->getType();
void X86_32ABIInfo::computeInfo(CGFunctionInfo &FI) const {
   } else if (FI.getHasRegParm())
     State.FreeRegs = FI.getRegParm();
   else if (State.CC == llvm::CallingConv::X86_RegCall) {
     State.FreeRegs = 5;
     State.FreeSSERegs = 8;
   } else
     State.FreeRegs = DefaultNumRegisterParameters;
 
-  if (!getCXXABI().classifyReturnType(FI)) {
+  if (!::classifyReturnType(getCXXABI(), FI, *this)) {
     FI.getReturnInfo() = classifyReturnType(FI.getReturnType(), State);
   } else if (FI.getReturnInfo().isIndirect()) {
     // The C++ ABI is not aware of register usage, so we have to check if the
     // return value was sret and put it in a register ourselves if appropriate.
     if (State.FreeRegs) {
       --State.FreeRegs;  // The sret parameter consumes a register.
       if (!IsMCUABI)
         FI.getReturnInfo().setInReg(true);
void X86_64ABIInfo::computeInfo(CGFunctionInfo &FI) const {
 
   bool IsRegCall = CallingConv == llvm::CallingConv::X86_RegCall;
 
   // Keep track of the number of assigned registers.
   unsigned FreeIntRegs = IsRegCall ? 11 : 6;
   unsigned FreeSSERegs = IsRegCall ? 16 : 8;
   unsigned NeededInt, NeededSSE;
 
-  if (!getCXXABI().classifyReturnType(FI)) {
+  if (!::classifyReturnType(getCXXABI(), FI, *this)) {
     if (IsRegCall && FI.getReturnType()->getTypePtr()->isRecordType() &&
         !FI.getReturnType()->getTypePtr()->isUnionType()) {
       FI.getReturnInfo() =
           classifyRegCallStructType(FI.getReturnType(), NeededInt, NeededSSE);
       if (FreeIntRegs >= NeededInt && FreeSSERegs >= NeededSSE) {
         FreeIntRegs -= NeededInt;
         FreeSSERegs -= NeededSSE;
       } else {
private:
   ABIArgInfo classifyArgumentType(QualType RetTy) const;
   bool isHomogeneousAggregateBaseType(QualType Ty) const override;
   bool isHomogeneousAggregateSmallEnough(const Type *Ty,
                                          uint64_t Members) const override;
 
   bool isIllegalVectorType(QualType Ty) const;
 
   void computeInfo(CGFunctionInfo &FI) const override {
-    if (!getCXXABI().classifyReturnType(FI))
+    if (!::classifyReturnType(getCXXABI(), FI, *this))
       FI.getReturnInfo() = classifyReturnType(FI.getReturnType());
 
     for (auto &it : FI.arguments())
       it.info = classifyArgumentType(it.type);
   }
 
   Address EmitDarwinVAArg(Address VAListAddr, QualType Ty,
                           CodeGenFunction &CGF) const;
void WindowsARMTargetCodeGenInfo::setTargetAttributes(
   ARMTargetCodeGenInfo::setTargetAttributes(D, GV, CGM);
   if (GV->isDeclaration())
     return;
   addStackProbeTargetAttributes(D, GV, CGM);
 }
 }
 
 void ARMABIInfo::computeInfo(CGFunctionInfo &FI) const {
-  if (!getCXXABI().classifyReturnType(FI))
+  if (!::classifyReturnType(getCXXABI(), FI, *this))
     FI.getReturnInfo() =
         classifyReturnType(FI.getReturnType(), FI.isVariadic());
 
   for (auto &I : FI.arguments())
     I.info = classifyArgumentType(I.type, FI.isVariadic());
 
   // Always honor user-specified calling convention.
   if (FI.getCallingConvention() != llvm::CallingConv::C)

cfe/trunk/lib/Sema/SemaDecl.cpp

void Sema::ActOnFields(Scope *S, SourceLocation RecLoc, Decl *EnclosingDecl,
 
   bool ObjCFieldLifetimeErrReported = false;
   for (ArrayRef<Decl *>::iterator i = Fields.begin(), end = Fields.end();
        i != end; ++i) {
     FieldDecl *FD = cast<FieldDecl>(*i);
 
     // Get the type for the field.
     const Type *FDTy = FD->getType().getTypePtr();
-    Qualifiers QS = FD->getType().getQualifiers();
 
     if (!FD->isAnonymousStructOrUnion()) {
       // Remember all fields written by the user.
       RecFields.push_back(FD);
     }
 
     // If the field is already invalid for some reason, don't emit more
     // diagnostics about it.
if (FDTy->isFunctionType()) {
         Record->setHasVolatileMember(true);
     } else if (FDTy->isObjCObjectType()) {
       /// A field cannot be an Objective-c object
       Diag(FD->getLocation(), diag::err_statically_allocated_object)
         << FixItHint::CreateInsertion(FD->getLocation(), "*");
       QualType T = Context.getObjCObjectPointerType(FD->getType());
       FD->setType(T);
     } else if (getLangOpts().allowsNonTrivialObjCLifetimeQualifiers() &&
-               Record && !ObjCFieldLifetimeErrReported &&
-               ((!getLangOpts().CPlusPlus &&
-                 QS.getObjCLifetime() == Qualifiers::OCL_Weak) ||
-                Record->isUnion())) {
+               Record && !ObjCFieldLifetimeErrReported && Record->isUnion()) {
       // It's an error in ARC or Weak if a field has lifetime.
       // We don't want to report this in a system header, though,
       // so we just make the field unavailable.
       // FIXME: that's really not sufficient; we need to make the type
       // itself invalid to, say, initialize or copy.
       QualType T = FD->getType();
       if (T.hasNonTrivialObjCLifetime()) {
         SourceLocation loc = FD->getLocation();
if (Record && !getLangOpts().CPlusPlus) {
       QualType FT = FD->getType();
       if (FT.isNonTrivialToPrimitiveDefaultInitialize())
         Record->setNonTrivialToPrimitiveDefaultInitialize();
       QualType::PrimitiveCopyKind PCK = FT.isNonTrivialToPrimitiveCopy();
       if (PCK != QualType::PCK_Trivial && PCK != QualType::PCK_VolatileTrivial)
         Record->setNonTrivialToPrimitiveCopy();
       if (FT.isDestructedType())
         Record->setNonTrivialToPrimitiveDestroy();
+      if (!FT.canPassInRegisters())
+        Record->setCanPassInRegisters(false);
     }
 
     if (Record && FD->getType().isVolatileQualified())
       Record->setHasVolatileMember(true);
     // Keep track of the number of named members.
     if (FD->getIdentifier())
       ++NumNamedMembers;
   }

cfe/trunk/lib/Serialization/ASTReaderDecl.cpp

 
 ASTDeclReader::RedeclarableResult
 ASTDeclReader::VisitRecordDeclImpl(RecordDecl *RD) {
   RedeclarableResult Redecl = VisitTagDecl(RD);
   RD->setHasFlexibleArrayMember(Record.readInt());
   RD->setAnonymousStructOrUnion(Record.readInt());
   RD->setHasObjectMember(Record.readInt());
   RD->setHasVolatileMember(Record.readInt());
+  RD->setCanPassInRegisters(Record.readInt());
   return Redecl;
 }
 
 void ASTDeclReader::VisitValueDecl(ValueDecl *VD) {
   VisitNamedDecl(VD);
   VD->setType(Record.readType());
 }
 
void ASTDeclReader::ReadCXXDefinitionData(
   Data.DefaultedDestructorIsDeleted = Record.readInt();
   Data.HasTrivialSpecialMembers = Record.readInt();
   Data.HasTrivialSpecialMembersForCall = Record.readInt();
   Data.DeclaredNonTrivialSpecialMembers = Record.readInt();
   Data.DeclaredNonTrivialSpecialMembersForCall = Record.readInt();
   Data.HasIrrelevantDestructor = Record.readInt();
   Data.HasConstexprNonCopyMoveConstructor = Record.readInt();
   Data.HasDefaultedDefaultConstructor = Record.readInt();
-  Data.CanPassInRegisters = Record.readInt();
   Data.DefaultedDefaultConstructorIsConstexpr = Record.readInt();
   Data.HasConstexprDefaultConstructor = Record.readInt();
   Data.HasNonLiteralTypeFieldsOrBases = Record.readInt();
   Data.ComputedVisibleConversions = Record.readInt();
   Data.UserProvidedDefaultConstructor = Record.readInt();
   Data.DeclaredSpecialMembers = Record.readInt();
   Data.ImplicitCopyConstructorCanHaveConstParamForVBase = Record.readInt();
   Data.ImplicitCopyConstructorCanHaveConstParamForNonVBase = Record.readInt();
#define MATCH_FIELD(Field) \
   MATCH_FIELD(DefaultedDestructorIsDeleted)
   OR_FIELD(HasTrivialSpecialMembers)
   OR_FIELD(HasTrivialSpecialMembersForCall)
   OR_FIELD(DeclaredNonTrivialSpecialMembers)
   OR_FIELD(DeclaredNonTrivialSpecialMembersForCall)
   MATCH_FIELD(HasIrrelevantDestructor)
   OR_FIELD(HasConstexprNonCopyMoveConstructor)
   OR_FIELD(HasDefaultedDefaultConstructor)
-  MATCH_FIELD(CanPassInRegisters)
   MATCH_FIELD(DefaultedDefaultConstructorIsConstexpr)
   OR_FIELD(HasConstexprDefaultConstructor)
   MATCH_FIELD(HasNonLiteralTypeFieldsOrBases)
   // ComputedVisibleConversions is handled below.
   MATCH_FIELD(UserProvidedDefaultConstructor)
   OR_FIELD(DeclaredSpecialMembers)
   MATCH_FIELD(ImplicitCopyConstructorCanHaveConstParamForVBase)
   MATCH_FIELD(ImplicitCopyConstructorCanHaveConstParamForNonVBase)

cfe/trunk/lib/Serialization/ASTWriter.cpp

void ASTRecordWriter::AddCXXDefinitionData(const CXXRecordDecl *D) {
   Record->push_back(Data.DefaultedDestructorIsDeleted);
   Record->push_back(Data.HasTrivialSpecialMembers);
   Record->push_back(Data.HasTrivialSpecialMembersForCall);
   Record->push_back(Data.DeclaredNonTrivialSpecialMembers);
   Record->push_back(Data.DeclaredNonTrivialSpecialMembersForCall);
   Record->push_back(Data.HasIrrelevantDestructor);
   Record->push_back(Data.HasConstexprNonCopyMoveConstructor);
   Record->push_back(Data.HasDefaultedDefaultConstructor);
-  Record->push_back(Data.CanPassInRegisters);
   Record->push_back(Data.DefaultedDefaultConstructorIsConstexpr);
   Record->push_back(Data.HasConstexprDefaultConstructor);
   Record->push_back(Data.HasNonLiteralTypeFieldsOrBases);
   Record->push_back(Data.ComputedVisibleConversions);
   Record->push_back(Data.UserProvidedDefaultConstructor);
   Record->push_back(Data.DeclaredSpecialMembers);
   Record->push_back(Data.ImplicitCopyConstructorCanHaveConstParamForVBase);
   Record->push_back(Data.ImplicitCopyConstructorCanHaveConstParamForNonVBase);

cfe/trunk/lib/Serialization/ASTWriterDecl.cpp

 }
 
 void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
   VisitTagDecl(D);
   Record.push_back(D->hasFlexibleArrayMember());
   Record.push_back(D->isAnonymousStructOrUnion());
   Record.push_back(D->hasObjectMember());
   Record.push_back(D->hasVolatileMember());
+  Record.push_back(D->canPassInRegisters());
 
   if (D->getDeclContext() == D->getLexicalDeclContext() &&
       !D->hasAttrs() &&
       !D->isImplicit() &&
       !D->isUsed(false) &&
       !D->hasExtInfo() &&
       !D->getTypedefNameForAnonDecl() &&
       D->getFirstDecl() == D->getMostRecentDecl() &&
void ASTWriter::WriteDeclAbbrevs() {
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // SourceLocation
   Abv->Add(BitCodeAbbrevOp(0));                         // ExtInfoKind
   // RecordDecl
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // FlexibleArrayMember
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // AnonymousStructUnion
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasObjectMember
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // hasVolatileMember
+  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // canPassInRegisters
   // DC
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // LexicalOffset
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // VisibleOffset
   DeclRecordAbbrev = Stream.EmitAbbrev(std::move(Abv));
 
   // Abbreviation for DECL_PARM_VAR
   Abv = std::make_shared<BitCodeAbbrev>();
   Abv->Add(BitCodeAbbrevOp(serialization::DECL_PARM_VAR));

cfe/trunk/test/CodeGenObjC/nontrivial-c-struct-exception.m

-// RUN: %clang_cc1 -triple arm64-apple-ios11 -fobjc-arc -fblocks -fobjc-runtime=ios-11.0 -fobjc-exceptions -fexceptions -fobjc-arc-exceptions -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple arm64-apple-ios11 -fobjc-arc -fblocks -fobjc-runtime=ios-11.0 -fobjc-exceptions -fexceptions -emit-llvm -o - %s | FileCheck %s
 
 // CHECK: %[[STRUCT_STRONG:.*]] = type { i32, i8* }
+// CHECK: %[[STRUCT_WEAK:.*]] = type { i32, i8* }
 
 typedef struct {
   int i;
   id f1;
 } Strong;
 
+typedef struct {
+  int i;
+  __weak id f1;
+} Weak;
+
 // CHECK: define void @testStrongException()
 // CHECK: %[[AGG_TMP:.*]] = alloca %[[STRUCT_STRONG]], align 8
 // CHECK: %[[AGG_TMP1:.*]] = alloca %[[STRUCT_STRONG]], align 8
 // CHECK: %[[CALL:.*]] = call [2 x i64] @genStrong()
 // CHECK: %[[V0:.*]] = bitcast %[[STRUCT_STRONG]]* %[[AGG_TMP]] to [2 x i64]*
 // CHECK: store [2 x i64] %[[CALL]], [2 x i64]* %[[V0]], align 8
 // CHECK: invoke [2 x i64] @genStrong()
 
 // CHECK: call void @calleeStrong([2 x i64] %{{.*}}, [2 x i64] %{{.*}})
 // CHECK-NEXT: ret void
 
 // CHECK: landingpad { i8*, i32 }
 // CHECK: %[[V9:.*]] = bitcast %[[STRUCT_STRONG]]* %[[AGG_TMP]] to i8**
 // CHECK: call void @__destructor_8_s8(i8** %[[V9]])
 // CHECK: br label
 
 // CHECK: resume
 
 Strong genStrong(void);
 void calleeStrong(Strong, Strong);
 
 void testStrongException(void) {
   calleeStrong(genStrong(), genStrong());
 }
+
+// CHECK: define void @testWeakException()
+// CHECK: %[[AGG_TMP:.*]] = alloca %[[STRUCT_WEAK]], align 8
+// CHECK: %[[AGG_TMP1:.*]] = alloca %[[STRUCT_WEAK]], align 8
+// CHECK: call void @genWeak(%[[STRUCT_WEAK]]* sret %[[AGG_TMP]])
+// CHECK: invoke void @genWeak(%[[STRUCT_WEAK]]* sret %[[AGG_TMP1]])
+
+// CHECK: call void @calleeWeak(%[[STRUCT_WEAK]]* %[[AGG_TMP]], %[[STRUCT_WEAK]]* %[[AGG_TMP1]])
+// CHECK: ret void
+
+// CHECK: landingpad { i8*, i32 }
+// CHECK: %[[V3:.*]] = bitcast %[[STRUCT_WEAK]]* %[[AGG_TMP]] to i8**
+// CHECK: call void @__destructor_8_w8(i8** %[[V3]])
+// CHECK: br label
+
+// CHECK: resume
+
+Weak genWeak(void);
+void calleeWeak(Weak, Weak);
+
+void testWeakException(void) {
+  calleeWeak(genWeak(), genWeak());
+}

cfe/trunk/test/CodeGenObjC/weak-in-c-struct.m

+// RUN: %clang_cc1 -triple arm64-apple-ios11 -fobjc-arc -fblocks -fobjc-runtime=ios-11.0 -emit-llvm -o - %s | FileCheck -check-prefix=ARM64 -check-prefix=COMMON %s
+// RUN: %clang_cc1 -triple thumbv7-apple-ios10 -fobjc-arc -fblocks -fobjc-runtime=ios-10.0 -emit-llvm -o - %s | FileCheck -check-prefix=COMMON %s
+// RUN: %clang_cc1 -triple x86_64-apple-macosx10.13 -fobjc-arc -fblocks -fobjc-runtime=macosx-10.13.0 -emit-llvm -o - %s | FileCheck -check-prefix=COMMON %s
+// RUN: %clang_cc1 -triple i386-apple-macosx10.13.0 -fobjc-arc -fblocks -fobjc-runtime=macosx-fragile-10.13.0 -emit-llvm -o - %s | FileCheck -check-prefix=COMMON %s
+
+typedef void (^BlockTy)(void);
+
+// COMMON: %[[STRUCT_WEAK:.*]] = type { i32, i8* }
+
+typedef struct {
+  int f0;
+  __weak id f1;
+} Weak;
+
+Weak getWeak(void);
+void calleeWeak(Weak);
+
+// ARM64: define void @test_constructor_destructor_Weak()
+// ARM64: %[[T:.*]] = alloca %[[STRUCT_WEAK]], align 8
+// ARM64: %[[V0:.*]] = bitcast %[[STRUCT_WEAK]]* %[[T]] to i8**
+// ARM64: call void @__default_constructor_8_w8(i8** %[[V0]])
+// ARM64: %[[V1:.*]] = bitcast %[[STRUCT_WEAK]]* %[[T]] to i8**
+// ARM64: call void @__destructor_8_w8(i8** %[[V1]])
+// ARM64: ret void
+
+// ARM64: define linkonce_odr hidden void @__default_constructor_8_w8(i8** %[[DST:.*]])
+// ARM64: %[[DST_ADDR:.*]] = alloca i8**, align 8
+// ARM64: store i8** %[[DST]], i8*** %[[DST_ADDR]], align 8
+// ARM64: %[[V0:.*]] = load i8**, i8*** %[[DST_ADDR]], align 8
+// ARM64: %[[V1]] = bitcast i8** %[[V0]] to i8*
+// ARM64: %[[V2:.*]] = getelementptr inbounds i8, i8* %[[V1]], i64 8
+// ARM64: %[[V3:.*]] = bitcast i8* %[[V2]] to i8**
+// ARM64: %[[V4:.*]] = bitcast i8** %[[V3]] to i8*
+// ARM64: call void @llvm.memset.p0i8.i64(i8* align 8 %[[V4]], i8 0, i64 8, i1 false)
+
+// ARM64: define linkonce_odr hidden void @__destructor_8_w8(i8** %[[DST:.*]])
+// ARM64: %[[DST_ADDR:.*]] = alloca i8**, align 8
+// ARM64: store i8** %[[DST]], i8*** %[[DST_ADDR]], align 8
+// ARM64: %[[V0:.*]] = load i8**, i8*** %[[DST_ADDR]], align 8
+// ARM64: %[[V1:.*]] = bitcast i8** %[[V0]] to i8*
+// ARM64: %[[V2:.*]] = getelementptr inbounds i8, i8* %[[V1]], i64 8
+// ARM64: %[[V3:.*]] = bitcast i8* %[[V2]] to i8**
+// ARM64: call void @objc_destroyWeak(i8** %[[V3]])
+
+void test_constructor_destructor_Weak(void) {
+  Weak t;
+}
+
+// ARM64: define void @test_copy_constructor_Weak(%[[STRUCT_WEAK]]* %{{.*}})
+// ARM64: call void @__copy_constructor_8_8_t0w4_w8(i8** %{{.*}}, i8** %{{.*}})
+// ARM64: call void @__destructor_8_w8(i8** %{{.*}})
+
+// ARM64: define linkonce_odr hidden void @__copy_constructor_8_8_t0w4_w8(i8** %[[DST:.*]], i8** %[[SRC:.*]])
+// ARM64: %[[DST_ADDR:.*]] = alloca i8**, align 8
+// ARM64: %[[SRC_ADDR:.*]] = alloca i8**, align 8
+// ARM64: store i8** %[[DST]], i8*** %[[DST_ADDR]], align 8
+// ARM64: store i8** %[[SRC]], i8*** %[[SRC_ADDR]], align 8
+// ARM64: %[[V0:.*]] = load i8**, i8*** %[[DST_ADDR]], align 8
+// ARM64: %[[V1:.*]] = load i8**, i8*** %[[SRC_ADDR]], align 8
+// ARM64: %[[V2:.*]] = bitcast i8** %[[V0]] to i32*
+// ARM64: %[[V3:.*]] = bitcast i8** %[[V1]] to i32*
+// ARM64: %[[V4:.*]] = load i32, i32* %[[V3]], align 8
+// ARM64: store i32 %[[V4]], i32* %[[V2]], align 8
+// ARM64: %[[V5:.*]] = bitcast i8** %[[V0]] to i8*
+// ARM64: %[[V6:.*]] = getelementptr inbounds i8, i8* %[[V5]], i64 8
+// ARM64: %[[V7:.*]] = bitcast i8* %[[V6]] to i8**
+// ARM64: %[[V8:.*]] = bitcast i8** %[[V1]] to i8*
+// ARM64: %[[V9:.*]] = getelementptr inbounds i8, i8* %[[V8]], i64 8
+// ARM64: %[[V10:.*]] = bitcast i8* %[[V9]] to i8**
+// ARM64: call void @objc_copyWeak(i8** %[[V7]], i8** %[[V10]])
+
+void test_copy_constructor_Weak(Weak *s) {
+  Weak t = *s;
+}
+
+// ARM64: define void @test_copy_assignment_Weak(%[[STRUCT_WEAK]]* %{{.*}}, %[[STRUCT_WEAK]]* %{{.*}})
+// ARM64: call void @__copy_assignment_8_8_t0w4_w8(i8** %{{.*}}, i8** %{{.*}})
+
+// ARM64: define linkonce_odr hidden void @__copy_assignment_8_8_t0w4_w8(i8** %[[DST:.*]], i8** %[[SRC:.*]])
+// ARM64: %[[DST_ADDR:.*]] = alloca i8**, align 8
+// ARM64: %[[SRC_ADDR:.*]] = alloca i8**, align 8
+// ARM64: store i8** %[[DST]], i8*** %[[DST_ADDR]], align 8
+// ARM64: store i8** %[[SRC]], i8*** %[[SRC_ADDR]], align 8
+// ARM64: %[[V0:.*]] = load i8**, i8*** %[[DST_ADDR]], align 8
+// ARM64: %[[V1:.*]] = load i8**, i8*** %[[SRC_ADDR]], align 8
+// ARM64: %[[V2:.*]] = bitcast i8** %[[V0]] to i32*
+// ARM64: %[[V3:.*]] = bitcast i8** %[[V1]] to i32*
+// ARM64: %[[V4:.*]] = load i32, i32* %[[V3]], align 8
+// ARM64: store i32 %[[V4]], i32* %[[V2]], align 8
+// ARM64: %[[V5:.*]] = bitcast i8** %[[V0]] to i8*
+// ARM64: %[[V6:.*]] = getelementptr inbounds i8, i8* %[[V5]], i64 8
+// ARM64: %[[V7:.*]] = bitcast i8* %[[V6]] to i8**
+// ARM64: %[[V8:.*]] = bitcast i8** %[[V1]] to i8*
+// ARM64: %[[V9:.*]] = getelementptr inbounds i8, i8* %[[V8]], i64 8
+// ARM64: %[[V10:.*]] = bitcast i8* %[[V9]] to i8**
+// ARM64: %[[V11:.*]] = call i8* @objc_loadWeakRetained(i8** %[[V10]])
+// ARM64: %[[V12:.*]] = call i8* @objc_storeWeak(i8** %[[V7]], i8* %[[V11]])
+// ARM64: call void @objc_release(i8* %[[V11]])
+
+void test_copy_assignment_Weak(Weak *d, Weak *s) {
+  *d = *s;
+}
+
+// ARM64: define internal void @__Block_byref_object_copy_(i8*, i8*)
+// ARM64: call void @__move_constructor_8_8_t0w4_w8(i8** %{{.*}}, i8** %{{.*}})
+
+// ARM64: define linkonce_odr hidden void @__move_constructor_8_8_t0w4_w8(i8** %[[DST:.*]], i8** %[[SRC:.*]])
+// ARM64: %[[DST_ADDR:.*]] = alloca i8**, align 8
+// ARM64: %[[SRC_ADDR:.*]] = alloca i8**, align 8
+// ARM64: store i8** %[[DST]], i8*** %[[DST_ADDR]], align 8
+// ARM64: store i8** %[[SRC]], i8*** %[[SRC_ADDR]], align 8
+// ARM64: %[[V0:.*]] = load i8**, i8*** %[[DST_ADDR]], align 8
+// ARM64: %[[V1:.*]] = load i8**, i8*** %[[SRC_ADDR]], align 8
+// ARM64: %[[V2:.*]] = bitcast i8** %[[V0]] to i32*
+// ARM64: %[[V3:.*]] = bitcast i8** %[[V1]] to i32*
+// ARM64: %[[V4:.*]] = load i32, i32* %[[V3]], align 8
+// ARM64: store i32 %[[V4]], i32* %[[V2]], align 8
+// ARM64: %[[V5:.*]] = bitcast i8** %[[V0]] to i8*
+// ARM64: %[[V6:.*]] = getelementptr inbounds i8, i8* %[[V5]], i64 8
+// ARM64: %[[V7:.*]] = bitcast i8* %[[V6]] to i8**
+// ARM64: %[[V8:.*]] = bitcast i8** %[[V1]] to i8*
+// ARM64: %[[V9:.*]] = getelementptr inbounds i8, i8* %[[V8]], i64 8
+// ARM64: %[[V10:.*]] = bitcast i8* %[[V9]] to i8**
+// ARM64: call void @objc_moveWeak(i8** %[[V7]], i8** %[[V10]])
+
+void test_move_constructor_Weak(void) {
+  __block Weak t;
+  BlockTy b = ^{ (void)t; };
+}
+
+// ARM64: define void @test_move_assignment_Weak(%[[STRUCT_WEAK]]* %{{.*}})
+// ARM64: call void @__move_assignment_8_8_t0w4_w8(i8** %{{.*}}, i8** %{{.*}})
+
+// ARM64: define linkonce_odr hidden void @__move_assignment_8_8_t0w4_w8(i8** %[[DST:.*]], i8** %[[SRC:.*]])
+// ARM64: %[[DST_ADDR:.*]] = alloca i8**, align 8
+// ARM64: %[[SRC_ADDR:.*]] = alloca i8**, align 8
+// ARM64: store i8** %[[DST]], i8*** %[[DST_ADDR]], align 8
+// ARM64: store i8** %[[SRC]], i8*** %[[SRC_ADDR]], align 8
+// ARM64: %[[V0:.*]] = load i8**, i8*** %[[DST_ADDR]], align 8
+// ARM64: %[[V1:.*]] = load i8**, i8*** %[[SRC_ADDR]], align 8
+// ARM64: %[[V2:.*]] = bitcast i8** %[[V0]] to i32*
+// ARM64: %[[V3:.*]] = bitcast i8** %[[V1]] to i32*
+// ARM64: %[[V4:.*]] = load i32, i32* %[[V3]], align 8
+// ARM64: store i32 %[[V4]], i32* %[[V2]], align 8
+// ARM64: %[[V5:.*]] = bitcast i8** %[[V0]] to i8*
+// ARM64: %[[V6:.*]] = getelementptr inbounds i8, i8* %[[V5]], i64 8
+// ARM64: %[[V7:.*]] = bitcast i8* %[[V6]] to i8**
+// ARM64: %[[V8:.*]] = bitcast i8** %[[V1]] to i8*
+// ARM64: %[[V9:.*]] = getelementptr inbounds i8, i8* %[[V8]], i64 8
+// ARM64: %[[V10:.*]] = bitcast i8* %[[V9]] to i8**
+// ARM64: %[[V11:.*]] = call i8* @objc_loadWeakRetained(i8** %[[V10]])
+// ARM64: %[[V12:.*]] = call i8* @objc_storeWeak(i8** %[[V7]], i8* %[[V11]])
+// ARM64: call void @objc_destroyWeak(i8** %[[V10]])
+// ARM64: call void @objc_release(i8* %[[V11]])
+
+void test_move_assignment_Weak(Weak *p) {
+  *p = getWeak();
+}
+
+// COMMON: define void @test_parameter_Weak(%[[STRUCT_WEAK]]* %[[A:.*]])
+// COMMON: %[[V0:.*]] = bitcast %[[STRUCT_WEAK]]* %[[A]] to i8**
+// COMMON: call void @__destructor_{{.*}}(i8** %[[V0]])
+
+void test_parameter_Weak(Weak a) {
+}
+
+// COMMON: define void @test_argument_Weak(%[[STRUCT_WEAK]]* %[[A:.*]])
+// COMMON: %[[A_ADDR:.*]] = alloca %[[STRUCT_WEAK]]*
+// COMMON: %[[AGG_TMP:.*]] = alloca %[[STRUCT_WEAK]]
+// COMMON: store %[[STRUCT_WEAK]]* %[[A]], %[[STRUCT_WEAK]]** %[[A_ADDR]]
+// COMMON: %[[V0:.*]] = load %[[STRUCT_WEAK]]*, %[[STRUCT_WEAK]]** %[[A_ADDR]]
+// COMMON: %[[V1:.*]] = bitcast %[[STRUCT_WEAK]]* %[[AGG_TMP]] to i8**
+// COMMON: %[[V2:.*]] = bitcast %[[STRUCT_WEAK]]* %[[V0]] to i8**
+// COMMON: call void @__copy_constructor_{{.*}}(i8** %[[V1]], i8** %[[V2]])
+// COMMON: call void @calleeWeak(%[[STRUCT_WEAK]]* %[[AGG_TMP]])
+// COMMON-NEXT: ret
+
+void test_argument_Weak(Weak *a) {
+  calleeWeak(*a);
+}
+
+// COMMON: define void @test_return_Weak(%[[STRUCT_WEAK]]* noalias sret %[[AGG_RESULT:.*]], %[[STRUCT_WEAK]]* %[[A:.*]])
+// COMMON: %[[A_ADDR:.*]] = alloca %[[STRUCT_WEAK]]*
+// COMMON: store %[[STRUCT_WEAK]]* %[[A]], %[[STRUCT_WEAK]]** %[[A_ADDR]]
+// COMMON: %[[V0:.*]] = load %[[STRUCT_WEAK]]*, %[[STRUCT_WEAK]]** %[[A_ADDR]]
+// COMMON: %[[V1:.*]] = bitcast %[[STRUCT_WEAK]]* %[[AGG_RESULT]] to i8**
+// COMMON: %[[V2:.*]] = bitcast %[[STRUCT_WEAK]]* %[[V0]] to i8**
+// COMMON: call void @__copy_constructor_{{.*}}(i8** %[[V1]], i8** %[[V2]])
+// COMMON: ret void
+
+Weak test_return_Weak(Weak *a) {
+  return *a;
+}