[ObjC++] Make parameter passing and function return compatible with ObjC

[ahatanak]

Summary

r326307 and r327870 made changes that enable strong and weak fields to be declared in C structs. This patch changes the ObjC++ ABI so that structs with strong or weak pointers can be passed to or returned from functions compiled in C mode.

ObjC and ObjC++ are currently incompatible because of the differences in the way structs are passed and destructed.

For example:

typedef struct {
  id f0;
  __weak id f1;
} S;

// this code is compiled in c++.
extern “C” {
  void foo(S s);
}

void caller(S a) {
  foo(a); // clang currently passes 'a' indirectly and the caller destructs 'a'.
}

// this function is compiled in c.
void foo(S a) {  // 'a' is passed directly and is destructed in the callee.
}

This patch fixes the incompatibility by passing and returning structs with strong or weak fields using the C ABI in C++ mode: strong and weak fields in a struct do not cause the struct to be destructed in the caller and __strong fields do not make the struct to be passed indirectly.

Also, this patch fixes the microsoft ABI bug mentioned here:

https://reviews.llvm.org/D41039?id=128767#inline-364710

[ahatanak]

I tried to move the code in MicrosoftCXXABI::getRecordArgABI and ItaniumCXXABI::passClassIndirect that determine whether a struct is passed indirectly to Sema::CheckCompletedCXXClass, but couldn't do so since getClangABICompat() is a method of CodeGenOpts, which Sema doesn't have access to. This would allow removing ForcePassIndirectly.

[rjmccall]

I think it's reasonable to pull that into LangOpts. It would need to be in LangOpts anyway if we e.g. fixed an ABI bug in struct layout and needed a compatibility handling to preserve the old behavior.

[ahatanak]

Make ClangABICompat a LangOption and remove ForcePassIndirectly. Move the logic in CodeGen that decides whether a parameter should be passed indirectly to Sema.

[rjmccall]

LGTM.

include/clang/AST/Decl.h

class RecordDecl : public TagDecl {
   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;
 
+  /// Indicates whether this struct is destroyed in the callee. This flag is
+  /// meaningless when Microsoft ABI is used since parameters are always
+  /// destroyed in the callee.
+  bool ParamDestroyedInCallee : 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,
bool canPassInRegisters() const {
     return CanPassInRegisters;
   }
 
   /// Set that we can pass this RecordDecl in registers.
   void setCanPassInRegisters(bool CanPass) {
     CanPassInRegisters = CanPass;
   }
 
+  bool isParamDestroyedInCallee() const {
+    return ParamDestroyedInCallee;
+  }
+
+  void setParamDestroyedInCallee(bool V) {
+    ParamDestroyedInCallee = V;
+  }
+
   /// \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 {

include/clang/AST/DeclCXX.h

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;
   }
 
-  /// 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
   /// non-static data member or base class.
   bool hasNonLiteralTypeFieldsOrBases() const {
     return data().HasNonLiteralTypeFieldsOrBases;
   }
 
   /// \brief Determine whether this class has a using-declaration that names
   /// a user-declared base class constructor.

include/clang/AST/Type.h

public:
   bool isCXX11PODType(const ASTContext &Context) const;
 
   /// Return true if this is a trivial type per (C++0x [basic.types]p9)
   bool isTrivialType(const ASTContext &Context) const;
 
   /// Return true if this is a trivially copyable type (C++0x [basic.types]p9)
   bool isTriviallyCopyableType(const ASTContext &Context) const;
 
-  /// Determine whether this is a class whose triviality for the purpose of
-  /// calls is overridden to be trivial because the class or the type of one of
-  /// its subobjects has attribute "trivial_abi".
-  bool hasTrivialABIOverride() const;
-
   // Don't promise in the API that anything besides 'const' can be
   // easily added.
 
   /// Add the `const` type qualifier to this QualType.
   void addConst() {
     addFastQualifiers(Qualifiers::Const);
   }
   QualType withConst() const {

include/clang/Basic/LangOptions.h

public:
 
   enum MSVCMajorVersion {
     MSVC2010 = 16,
     MSVC2012 = 17,
     MSVC2013 = 18,
     MSVC2015 = 19
   };
 
+  /// Clang versions with different platform ABI conformance.
+  enum class ClangABI {
+    /// Attempt to be ABI-compatible with code generated by Clang 3.8.x
+    /// (SVN r257626). This causes <1 x long long> to be passed in an
+    /// integer register instead of an SSE register on x64_64.
+    Ver3_8,
+
+    /// Attempt to be ABI-compatible with code generated by Clang 4.0.x
+    /// (SVN r291814). This causes move operations to be ignored when
+    /// determining whether a class type can be passed or returned directly.
+    Ver4,
+
+    /// Conform to the underlying platform's C and C++ ABIs as closely
+    /// as we can.
+    Latest
+  };
+
   enum FPContractModeKind {
     // Form fused FP ops only where result will not be affected.
     FPC_Off,
 
     // Form fused FP ops according to FP_CONTRACT rules.
     FPC_On,
 
     // Aggressively fuse FP ops (E.g. FMA).

include/clang/Basic/LangOptions.def

 LANGOPT(XRayInstrument, 1, 0, "controls whether to do XRay instrumentation")
 LANGOPT(XRayAlwaysEmitCustomEvents, 1, 0,
         "controls whether to always emit intrinsic calls to "
         "__xray_customevent(...) builtin.")
 
 BENIGN_LANGOPT(AllowEditorPlaceholders, 1, 0,
                "allow editor placeholders in source")
 
+ENUM_LANGOPT(ClangABICompat, ClangABI, 4, ClangABI::Latest,
+             "version of Clang that we should attempt to be ABI-compatible "
+             "with")
+
 #undef LANGOPT
 #undef COMPATIBLE_LANGOPT
 #undef BENIGN_LANGOPT
 #undef ENUM_LANGOPT
 #undef COMPATIBLE_ENUM_LANGOPT
 #undef BENIGN_ENUM_LANGOPT
 #undef VALUE_LANGOPT
 #undef COMPATIBLE_VALUE_LANGOPT
 #undef BENIGN_VALUE_LANGOPT
 

include/clang/Basic/TargetInfo.h

virtual CallingConvCheckResult checkCallingConvention(CallingConv CC) const {
     switch (CC) {
       default:
         return CCCR_Warning;
       case CC_C:
         return CCCR_OK;
     }
   }
 
+  enum CallingConvKind {
+    CCK_Default,
+    CCK_ClangABI4OrPS4,
+    CCK_MicrosoftX86_64
+  };
+
+  virtual CallingConvKind getCallingConvKind(bool ClangABICompat4) const;
+
   /// Controls if __builtin_longjmp / __builtin_setjmp can be lowered to
   /// llvm.eh.sjlj.longjmp / llvm.eh.sjlj.setjmp.
   virtual bool hasSjLjLowering() const {
     return false;
   }
 
   /// Check if the target supports CFProtection branch.
   virtual bool

include/clang/Frontend/CodeGenOptions.def

 CODEGENOPT(CorrectlyRoundedDivSqrt, 1, 0) ///< -cl-fp32-correctly-rounded-divide-sqrt
 CODEGENOPT(UniformWGSize     , 1, 0) ///< -cl-uniform-work-group-size
 CODEGENOPT(NoZeroInitializedInBSS , 1, 0) ///< -fno-zero-initialized-in-bss.
 /// \brief Method of Objective-C dispatch to use.
 ENUM_CODEGENOPT(ObjCDispatchMethod, ObjCDispatchMethodKind, 2, Legacy)
 CODEGENOPT(OmitLeafFramePointer , 1, 0) ///< Set when -momit-leaf-frame-pointer is
                                         ///< enabled.
 
-/// A version of Clang that we should attempt to be ABI-compatible with.
-ENUM_CODEGENOPT(ClangABICompat, ClangABI, 4, ClangABI::Latest)
-
 VALUE_CODEGENOPT(OptimizationLevel, 2, 0) ///< The -O[0-3] option specified.
 VALUE_CODEGENOPT(OptimizeSize, 2, 0) ///< If -Os (==1) or -Oz (==2) is specified.
 
 /// \brief Choose profile instrumenation kind or no instrumentation.
 ENUM_CODEGENOPT(ProfileInstr, ProfileInstrKind, 2, ProfileNone)
 /// \brief Choose profile kind for PGO use compilation.
 ENUM_CODEGENOPT(ProfileUse, ProfileInstrKind, 2, ProfileNone)
 CODEGENOPT(CoverageMapping , 1, 0) ///< Generate coverage mapping regions to

lib/AST/ASTContext.cpp

if (TypeSourceInfo *TSInfo = FD->getTypeSourceInfo()) {
     assert(TypeLoc::getFullDataSizeForType(Updated) ==
                TypeLoc::getFullDataSizeForType(TSInfo->getType()) &&
            "TypeLoc size mismatch from updating exception specification");
     TSInfo->overrideType(Updated);
   }
 }
 
 bool ASTContext::isParamDestroyedInCallee(QualType T) const {
-  return getTargetInfo().getCXXABI().areArgsDestroyedLeftToRightInCallee() ||
-         T.hasTrivialABIOverride() ||
-         T.isDestructedType() == QualType::DK_nontrivial_c_struct;
+  if (getTargetInfo().getCXXABI().areArgsDestroyedLeftToRightInCallee())
+    return true;
+  if (const auto *RT = T->getBaseElementTypeUnsafe()->getAs<RecordType>())
+    return RT->getDecl()->isParamDestroyedInCallee();
+  return false;
 }
 
 /// getComplexType - Return the uniqued reference to the type for a complex
 /// number with the specified element type.
 QualType ASTContext::getComplexType(QualType T) const {
   // Unique pointers, to guarantee there is only one pointer of a particular
   // structure.
   llvm::FoldingSetNodeID ID;

lib/AST/Decl.cpp

RecordDecl::RecordDecl(Kind DK, TagKind TK, const ASTContext &C,
                        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),
-      CanPassInRegisters(true) {
+      CanPassInRegisters(true), ParamDestroyedInCallee(false) {
   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);

lib/AST/DeclCXX.cpp

if (T->isObjCRetainableType() || T.isObjCGCStrong()) {
         //   type (or array thereof), it is a non-POD type and its
         //   default constructor (if any), copy constructor, move constructor,
         //   copy assignment operator, move assignment operator, and destructor are
         //   non-trivial.
         setHasObjectMember(true);
         struct DefinitionData &Data = data();
         Data.PlainOldData = false;
         Data.HasTrivialSpecialMembers = 0;
-        Data.HasTrivialSpecialMembersForCall = 0;
+
+        // __strong or __weak fields do not make special functions non-trivial
+        // for the purpose of calls.
+        Qualifiers::ObjCLifetime LT = T.getQualifiers().getObjCLifetime();
+        if (LT != Qualifiers::OCL_Strong && LT != Qualifiers::OCL_Weak)
+          data().HasTrivialSpecialMembersForCall = 0;
+
+        // Structs with __weak fields should never be passed directly.
+        if (LT == Qualifiers::OCL_Weak)
+          setCanPassInRegisters(false);
+
         Data.HasIrrelevantDestructor = false;
       } else if (!Context.getLangOpts().ObjCAutoRefCount) {
         setHasObjectMember(true);
       }
     } else if (!T.isCXX98PODType(Context))
       data().PlainOldData = false;
     
     if (T->isReferenceType()) {

lib/AST/Type.cpp

if (const RecordType *RT = CanonicalType->getAs<RecordType>()) {
 
     return true;
   }
 
   // No other types can match.
   return false;
 }
 
-bool QualType::hasTrivialABIOverride() const {
-  if (const auto *RD = getTypePtr()->getAsCXXRecordDecl())
-    return RD->hasTrivialABIOverride();
-  return false;
-}
-
 bool QualType::isNonWeakInMRRWithObjCWeak(const ASTContext &Context) const {
   return !Context.getLangOpts().ObjCAutoRefCount &&
          Context.getLangOpts().ObjCWeak &&
          getObjCLifetime() != Qualifiers::OCL_Weak;
 }
 
 QualType::PrimitiveDefaultInitializeKind
 QualType::isNonTrivialToPrimitiveDefaultInitialize() const {

lib/Basic/TargetInfo.cpp

for (const auto &F : FeatureVec) {
     StringRef Name = F;
     // Apply the feature via the target.
     bool Enabled = Name[0] == '+';
     setFeatureEnabled(Features, Name.substr(1), Enabled);
   }
   return true;
 }
 
+TargetInfo::CallingConvKind
+TargetInfo::getCallingConvKind(bool ClangABICompat4) const {
+  if (getCXXABI() != TargetCXXABI::Microsoft &&
+      (ClangABICompat4 || getTriple().getOS() == llvm::Triple::PS4))
+    return CCK_ClangABI4OrPS4;
+  return CCK_Default;
+}
+
 LangAS TargetInfo::getOpenCLTypeAddrSpace(OpenCLTypeKind TK) const {
   switch (TK) {
   case OCLTK_Image:
   case OCLTK_Pipe:
     return LangAS::opencl_global;
 
   case OCLTK_Sampler:
     return LangAS::opencl_constant;

lib/Basic/Targets/X86.h

public:
 
   void getTargetDefines(const LangOptions &Opts,
                         MacroBuilder &Builder) const override {
     WindowsX86_64TargetInfo::getTargetDefines(Opts, Builder);
     WindowsX86_64TargetInfo::getVisualStudioDefines(Opts, Builder);
     Builder.defineMacro("_M_X64", "100");
     Builder.defineMacro("_M_AMD64", "100");
   }
+
+  TargetInfo::CallingConvKind
+  getCallingConvKind(bool ClangABICompat4) const override {
+    return CCK_MicrosoftX86_64;
+  }
 };
 
 // x86-64 MinGW target
 class LLVM_LIBRARY_VISIBILITY MinGWX86_64TargetInfo
     : public WindowsX86_64TargetInfo {
 public:
   MinGWX86_64TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : WindowsX86_64TargetInfo(Triple, Opts) {

lib/CodeGen/CGCall.cpp

if (HasAggregateEvalKind && getContext().isParamDestroyedInCallee(type)) {
     // If we're using inalloca, use the argument memory.  Otherwise, use a
     // temporary.
     AggValueSlot Slot;
     if (args.isUsingInAlloca())
       Slot = createPlaceholderSlot(*this, type);
     else
       Slot = CreateAggTemp(type, "agg.tmp");
 
-    bool DestroyedInCallee = true, NeedsEHCleanup = true;
-    if (const auto *RD = type->getAsCXXRecordDecl()) {
-      DestroyedInCallee =
-          RD && RD->hasNonTrivialDestructor() &&
-          (CGM.getCXXABI().getRecordArgABI(RD) != CGCXXABI::RAA_Default ||
-           RD->hasTrivialABIOverride());
-    } else {
-      NeedsEHCleanup = needsEHCleanup(type.isDestructedType());
-    }
-
-    if (DestroyedInCallee)
-      Slot.setExternallyDestructed();
 
     EmitAggExpr(E, Slot);
     RValue RV = Slot.asRValue();
     args.add(RV, type);
 
-    if (DestroyedInCallee && NeedsEHCleanup) {
+    if (type->getAsCXXRecordDecl() || needsEHCleanup(type.isDestructedType())) {
       // Create a no-op GEP between the placeholder and the cleanup so we can
       // RAUW it successfully.  It also serves as a marker of the first
       // instruction where the cleanup is active.
       pushFullExprCleanup<DestroyUnpassedArg>(EHCleanup, Slot.getAddress(),
                                               type);
       // This unreachable is a temporary marker which will be removed later.
       llvm::Instruction *IsActive = Builder.CreateUnreachable();
       args.addArgCleanupDeactivation(EHStack.getInnermostEHScope(), IsActive);

lib/CodeGen/ItaniumCXXABI.cpp

ItaniumCXXABI(CodeGen::CodeGenModule &CGM,
                 bool UseARMGuardVarABI = false) :
     CGCXXABI(CGM), UseARMMethodPtrABI(UseARMMethodPtrABI),
     UseARMGuardVarABI(UseARMGuardVarABI),
     Use32BitVTableOffsetABI(false) { }
 
   bool classifyReturnType(CGFunctionInfo &FI) const override;
 
   bool passClassIndirect(const CXXRecordDecl *RD) const {
-    // Clang <= 4 used the pre-C++11 rule, which ignores move operations.
-    // The PS4 platform ABI follows the behavior of Clang 3.2.
-    if (CGM.getCodeGenOpts().getClangABICompat() <=
-            CodeGenOptions::ClangABI::Ver4 ||
-        CGM.getTriple().getOS() == llvm::Triple::PS4)
-      return RD->hasNonTrivialDestructorForCall() ||
-             RD->hasNonTrivialCopyConstructorForCall();
     return !canCopyArgument(RD);
   }
 
   RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const override {
     // If C++ prohibits us from making a copy, pass by address.
     if (passClassIndirect(RD))
       return RAA_Indirect;
     return RAA_Default;

lib/CodeGen/MicrosoftCXXABI.cpp

case llvm::Triple::x86:
     if (!canCopyArgument(RD))
       return RAA_DirectInMemory;
 
     // Otherwise, construct the argument into a temporary and copy the bytes
     // into the outgoing argument memory.
     return RAA_Default;
 
   case llvm::Triple::x86_64:
-    bool CopyCtorIsTrivial = false, CopyCtorIsTrivialForCall = false;
-    bool DtorIsTrivialForCall = false;
-
-    // If a class has at least one non-deleted, trivial copy constructor, it
-    // is passed according to the C ABI. Otherwise, it is passed indirectly.
-    //
-    // Note: This permits classes with non-trivial copy or move ctors to be
-    // passed in registers, so long as they *also* have a trivial copy ctor,
-    // which is non-conforming.
-    if (RD->needsImplicitCopyConstructor()) {
-      if (!RD->defaultedCopyConstructorIsDeleted()) {
-        if (RD->hasTrivialCopyConstructor())
-          CopyCtorIsTrivial = true;
-        if (RD->hasTrivialCopyConstructorForCall())
-          CopyCtorIsTrivialForCall = true;
-      }
-    } else {
-      for (const CXXConstructorDecl *CD : RD->ctors()) {
-        if (CD->isCopyConstructor() && !CD->isDeleted()) {
-          if (CD->isTrivial())
-            CopyCtorIsTrivial = true;
-          if (CD->isTrivialForCall())
-            CopyCtorIsTrivialForCall = true;
-        }
-      }
-    }
-
-    if (RD->needsImplicitDestructor()) {
-      if (!RD->defaultedDestructorIsDeleted() &&
-          RD->hasTrivialDestructorForCall())
-        DtorIsTrivialForCall = true;
-    } else if (const auto *D = RD->getDestructor()) {
-      if (!D->isDeleted() && D->isTrivialForCall())
-        DtorIsTrivialForCall = true;
-    }
-
-    // If the copy ctor and dtor are both trivial-for-calls, pass direct.
-    if (CopyCtorIsTrivialForCall && DtorIsTrivialForCall)
-      return RAA_Default;
-
-    // If a class has a destructor, we'd really like to pass it indirectly
-    // because it allows us to elide copies.  Unfortunately, MSVC makes that
-    // impossible for small types, which it will pass in a single register or
-    // stack slot. Most objects with dtors are large-ish, so handle that early.
-    // We can't call out all large objects as being indirect because there are
-    // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
-    // how we pass large POD types.
-
-    // Note: This permits small classes with nontrivial destructors to be
-    // passed in registers, which is non-conforming.
-    if (CopyCtorIsTrivial &&
-        getContext().getTypeSize(RD->getTypeForDecl()) <= 64)
-      return RAA_Default;
-    return RAA_Indirect;
+    return !canCopyArgument(RD) ? RAA_Indirect : RAA_Default;
   }
 
   llvm_unreachable("invalid enum");
 }
 
 void MicrosoftCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
                                               const CXXDeleteExpr *DE,
                                               Address Ptr,

lib/CodeGen/TargetInfo.cpp

class X86_64ABIInfo : public SwiftABIInfo {
   bool honorsRevision0_98() const {
     return !getTarget().getTriple().isOSDarwin();
   }
 
   /// GCC classifies <1 x long long> as SSE but some platform ABIs choose to
   /// classify it as INTEGER (for compatibility with older clang compilers).
   bool classifyIntegerMMXAsSSE() const {
     // Clang <= 3.8 did not do this.
-    if (getCodeGenOpts().getClangABICompat() <=
-        CodeGenOptions::ClangABI::Ver3_8)
+    if (getContext().getLangOpts().getClangABICompat() <=
+        LangOptions::ClangABI::Ver3_8)
       return false;
 
     const llvm::Triple &Triple = getTarget().getTriple();
     if (Triple.isOSDarwin() || Triple.getOS() == llvm::Triple::PS4)
       return false;
     if (Triple.isOSFreeBSD() && Triple.getOSMajorVersion() >= 10)
       return false;
     return true;

lib/Frontend/CompilerInvocation.cpp

static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   setPGOInstrumentor(Opts, Args, Diags);
   Opts.InstrProfileOutput =
       Args.getLastArgValue(OPT_fprofile_instrument_path_EQ);
   Opts.ProfileInstrumentUsePath =
       Args.getLastArgValue(OPT_fprofile_instrument_use_path_EQ);
   if (!Opts.ProfileInstrumentUsePath.empty())
     setPGOUseInstrumentor(Opts, Opts.ProfileInstrumentUsePath);
 
-  if (Arg *A = Args.getLastArg(OPT_fclang_abi_compat_EQ)) {
-    Opts.setClangABICompat(CodeGenOptions::ClangABI::Latest);
-
-    StringRef Ver = A->getValue();
-    std::pair<StringRef, StringRef> VerParts = Ver.split('.');
-    unsigned Major, Minor = 0;
-
-    // Check the version number is valid: either 3.x (0 <= x <= 9) or
-    // y or y.0 (4 <= y <= current version).
-    if (!VerParts.first.startswith("0") &&
-        !VerParts.first.getAsInteger(10, Major) &&
-        3 <= Major && Major <= CLANG_VERSION_MAJOR &&
-        (Major == 3 ? VerParts.second.size() == 1 &&
-                      !VerParts.second.getAsInteger(10, Minor)
-                    : VerParts.first.size() == Ver.size() ||
-                      VerParts.second == "0")) {
-      // Got a valid version number.
-      if (Major == 3 && Minor <= 8)
-        Opts.setClangABICompat(CodeGenOptions::ClangABI::Ver3_8);
-      else if (Major <= 4)
-        Opts.setClangABICompat(CodeGenOptions::ClangABI::Ver4);
-    } else if (Ver != "latest") {
-      Diags.Report(diag::err_drv_invalid_value)
-          << A->getAsString(Args) << A->getValue();
-    }
-  }
-
   Opts.CoverageMapping =
       Args.hasFlag(OPT_fcoverage_mapping, OPT_fno_coverage_mapping, false);
   Opts.DumpCoverageMapping = Args.hasArg(OPT_dump_coverage_mapping);
   Opts.AsmVerbose = Args.hasArg(OPT_masm_verbose);
   Opts.PreserveAsmComments = !Args.hasArg(OPT_fno_preserve_as_comments);
   Opts.AssumeSaneOperatorNew = !Args.hasArg(OPT_fno_assume_sane_operator_new);
   Opts.ObjCAutoRefCountExceptions = Args.hasArg(OPT_fobjc_arc_exceptions);
   Opts.CXAAtExit = !Args.hasArg(OPT_fno_use_cxa_atexit);
#include "clang/Frontend/LangStandards.def"
   // -fxray-{always,never}-instrument= filenames.
   Opts.XRayAlwaysInstrumentFiles =
       Args.getAllArgValues(OPT_fxray_always_instrument);
   Opts.XRayNeverInstrumentFiles =
       Args.getAllArgValues(OPT_fxray_never_instrument);
 
   // -fallow-editor-placeholders
   Opts.AllowEditorPlaceholders = Args.hasArg(OPT_fallow_editor_placeholders);
+
+  if (Arg *A = Args.getLastArg(OPT_fclang_abi_compat_EQ)) {
+    Opts.setClangABICompat(LangOptions::ClangABI::Latest);
+
+    StringRef Ver = A->getValue();
+    std::pair<StringRef, StringRef> VerParts = Ver.split('.');
+    unsigned Major, Minor = 0;
+
+    // Check the version number is valid: either 3.x (0 <= x <= 9) or
+    // y or y.0 (4 <= y <= current version).
+    if (!VerParts.first.startswith("0") &&
+        !VerParts.first.getAsInteger(10, Major) &&
+        3 <= Major && Major <= CLANG_VERSION_MAJOR &&
+        (Major == 3 ? VerParts.second.size() == 1 &&
+                      !VerParts.second.getAsInteger(10, Minor)
+                    : VerParts.first.size() == Ver.size() ||
+                      VerParts.second == "0")) {
+      // Got a valid version number.
+      if (Major == 3 && Minor <= 8)
+        Opts.setClangABICompat(LangOptions::ClangABI::Ver3_8);
+      else if (Major <= 4)
+        Opts.setClangABICompat(LangOptions::ClangABI::Ver4);
+    } else if (Ver != "latest") {
+      Diags.Report(diag::err_drv_invalid_value)
+          << A->getAsString(Args) << A->getValue();
+    }
+  }
 }
 
 static bool isStrictlyPreprocessorAction(frontend::ActionKind Action) {
   switch (Action) {
   case frontend::ASTDeclList:
   case frontend::ASTDump:
   case frontend::ASTPrint:
   case frontend::ASTView:

lib/Sema/SemaDecl.cpp

for (ArrayRef<Decl *>::iterator i = Fields.begin(), end = Fields.end();
 
     if (Record && !getLangOpts().CPlusPlus && !FD->hasAttr<UnavailableAttr>()) {
       QualType FT = FD->getType();
       if (FT.isNonTrivialToPrimitiveDefaultInitialize())
         Record->setNonTrivialToPrimitiveDefaultInitialize(true);
       QualType::PrimitiveCopyKind PCK = FT.isNonTrivialToPrimitiveCopy();
       if (PCK != QualType::PCK_Trivial && PCK != QualType::PCK_VolatileTrivial)
         Record->setNonTrivialToPrimitiveCopy(true);
-      if (FT.isDestructedType())
+      if (FT.isDestructedType()) {
         Record->setNonTrivialToPrimitiveDestroy(true);
+        Record->setParamDestroyedInCallee(true);
+      }
       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())

lib/Sema/SemaDeclCXX.cpp

static void DefineImplicitSpecialMember(Sema &S, CXXMethodDecl *MD,
   case Sema::CXXMoveAssignment:
     S.DefineImplicitMoveAssignment(DefaultLoc, MD);
     break;
   case Sema::CXXInvalid:
     llvm_unreachable("Invalid special member.");
   }
 }
 
-/// Determine whether a type is permitted to be passed or returned in
-/// registers, per C++ [class.temporary]p3.
-static bool computeCanPassInRegisters(Sema &S, CXXRecordDecl *D) {
+/// Determine whether a type would be destructed in the callee if it had a
+/// non-trivial destructor. The rules here are based on C++ [class.temporary]p3,
+/// which determines whether a struct can be passed to or returned from
+/// functions in registers.
+static bool paramCanBeDestroyedInCallee(Sema &S, CXXRecordDecl *D,
+                                        TargetInfo::CallingConvKind CCK) {
   if (D->isDependentType() || D->isInvalidDecl())
     return false;
 
+  // Clang <= 4 used the pre-C++11 rule, which ignores move operations.
+  // The PS4 platform ABI follows the behavior of Clang 3.2.
+  if (CCK == TargetInfo::CCK_ClangABI4OrPS4)
+    return !D->hasNonTrivialDestructorForCall() &&
+           !D->hasNonTrivialCopyConstructorForCall();
+
   // Per C++ [class.temporary]p3, the relevant condition is:
   //   each copy constructor, move constructor, and destructor of X is
   //   either trivial or deleted, and X has at least one non-deleted copy
   //   or move constructor
   bool HasNonDeletedCopyOrMove = false;
 
   if (D->needsImplicitCopyConstructor() &&
       !D->defaultedCopyConstructorIsDeleted()) {
for (const CXXMethodDecl *MD : D->methods()) {
 
     if (!MD->isTrivialForCall())
       return false;
   }
 
   return HasNonDeletedCopyOrMove;
 }
 
+static bool computeCanPassInRegister(bool DestroyedInCallee,
+                                     const CXXRecordDecl *RD,
+                                     TargetInfo::CallingConvKind CCK,
+                                     Sema &S) {
+  if (RD->isDependentType() || RD->isInvalidDecl())
+    return true;
+
+  // The param cannot be passed in registers if CanPassInRegisters is already
+  // set to false.
+  if (!RD->canPassInRegisters())
+    return false;
+
+  if (CCK != TargetInfo::CCK_MicrosoftX86_64)
+    return DestroyedInCallee;
+
+  bool CopyCtorIsTrivial = false, CopyCtorIsTrivialForCall = false;
+  bool DtorIsTrivialForCall = false;
+
+  // If a class has at least one non-deleted, trivial copy constructor, it
+  // is passed according to the C ABI. Otherwise, it is passed indirectly.
+  //
+  // Note: This permits classes with non-trivial copy or move ctors to be
+  // passed in registers, so long as they *also* have a trivial copy ctor,
+  // which is non-conforming.
+  if (RD->needsImplicitCopyConstructor()) {
+    if (!RD->defaultedCopyConstructorIsDeleted()) {
+      if (RD->hasTrivialCopyConstructor())
+        CopyCtorIsTrivial = true;
+      if (RD->hasTrivialCopyConstructorForCall())
+        CopyCtorIsTrivialForCall = true;
+    }
+  } else {
+    for (const CXXConstructorDecl *CD : RD->ctors()) {
+      if (CD->isCopyConstructor() && !CD->isDeleted()) {
+        if (CD->isTrivial())
+          CopyCtorIsTrivial = true;
+        if (CD->isTrivialForCall())
+          CopyCtorIsTrivialForCall = true;
+      }
+    }
+  }
+
+  if (RD->needsImplicitDestructor()) {
+    if (!RD->defaultedDestructorIsDeleted() &&
+        RD->hasTrivialDestructorForCall())
+      DtorIsTrivialForCall = true;
+  } else if (const auto *D = RD->getDestructor()) {
+    if (!D->isDeleted() && D->isTrivialForCall())
+      DtorIsTrivialForCall = true;
+  }
+
+  // If the copy ctor and dtor are both trivial-for-calls, pass direct.
+  if (CopyCtorIsTrivialForCall && DtorIsTrivialForCall)
+    return true;
+
+  // If a class has a destructor, we'd really like to pass it indirectly
+  // because it allows us to elide copies.  Unfortunately, MSVC makes that
+  // impossible for small types, which it will pass in a single register or
+  // stack slot. Most objects with dtors are large-ish, so handle that early.
+  // We can't call out all large objects as being indirect because there are
+  // multiple x64 calling conventions and the C++ ABI code shouldn't dictate
+  // how we pass large POD types.
+
+  // Note: This permits small classes with nontrivial destructors to be
+  // passed in registers, which is non-conforming.
+  if (CopyCtorIsTrivial &&
+      S.getASTContext().getTypeSize(RD->getTypeForDecl()) <= 64)
+    return true;
+  return false;
+}
+
 /// \brief Perform semantic checks on a class definition that has been
 /// completing, introducing implicitly-declared members, checking for
 /// abstract types, etc.
 void Sema::CheckCompletedCXXClass(CXXRecordDecl *Record) {
   if (!Record)
     return;
 
   if (Record->isAbstract() && !Record->isInvalidDecl()) {
void Sema::CheckCompletedCXXClass(CXXRecordDecl *Record) {
   // support "ms_struct except for C++ stuff" as a secondary ABI.
   if (Record->isMsStruct(Context) &&
       (Record->isPolymorphic() || Record->getNumBases())) {
     Diag(Record->getLocation(), diag::warn_cxx_ms_struct);
   }
 
   checkClassLevelDLLAttribute(Record);
 
-  Record->setCanPassInRegisters(computeCanPassInRegisters(*this, Record));
+  bool ClangABICompat4 =
+      Context.getLangOpts().getClangABICompat() <= LangOptions::ClangABI::Ver4;
+  TargetInfo::CallingConvKind CCK =
+      Context.getTargetInfo().getCallingConvKind(ClangABICompat4);
+  bool DestroyedInCallee = paramCanBeDestroyedInCallee(*this, Record, CCK);
+
+  if (Record->hasNonTrivialDestructor())
+    Record->setParamDestroyedInCallee(DestroyedInCallee);
+
+  Record->setCanPassInRegisters(
+      computeCanPassInRegister(DestroyedInCallee, Record, CCK, *this));
 }
 
 /// Look up the special member function that would be called by a special
 /// member function for a subobject of class type.
 ///
 /// \param Class The class type of the subobject.
 /// \param CSM The kind of special member function.
 /// \param FieldQuals If the subobject is a field, its cv-qualifiers.

lib/Serialization/ASTReaderDecl.cpp

ASTDeclReader::VisitRecordDeclImpl(RecordDecl *RD) {
   RD->setHasFlexibleArrayMember(Record.readInt());
   RD->setAnonymousStructOrUnion(Record.readInt());
   RD->setHasObjectMember(Record.readInt());
   RD->setHasVolatileMember(Record.readInt());
   RD->setNonTrivialToPrimitiveDefaultInitialize(Record.readInt());
   RD->setNonTrivialToPrimitiveCopy(Record.readInt());
   RD->setNonTrivialToPrimitiveDestroy(Record.readInt());
   RD->setCanPassInRegisters(Record.readInt());
+  RD->setParamDestroyedInCallee(Record.readInt());
   return Redecl;
 }
 
 void ASTDeclReader::VisitValueDecl(ValueDecl *VD) {
   VisitNamedDecl(VD);
   VD->setType(Record.readType());
 }
 
while (Record.getIdx() < Record.size()) {
 
     case UPD_CXX_INSTANTIATED_CLASS_DEFINITION: {
       auto *RD = cast<CXXRecordDecl>(D);
       auto *OldDD = RD->getCanonicalDecl()->DefinitionData;
       bool HadRealDefinition =
           OldDD && (OldDD->Definition != RD ||
                     !Reader.PendingFakeDefinitionData.count(OldDD));
       RD->setCanPassInRegisters(Record.readInt());
+      RD->setParamDestroyedInCallee(Record.readInt());
       ReadCXXRecordDefinition(RD, /*Update*/true);
 
       // Visible update is handled separately.
       uint64_t LexicalOffset = ReadLocalOffset();
       if (!HadRealDefinition && LexicalOffset) {
         Record.readLexicalDeclContextStorage(LexicalOffset, RD);
         Reader.PendingFakeDefinitionData.erase(OldDD);
       }

lib/Serialization/ASTWriter.cpp

for (auto &Update : DeclUpdate.second) {
         Record.AddStmt(
             cast<FieldDecl>(Update.getDecl())->getInClassInitializer());
         break;
 
       case UPD_CXX_INSTANTIATED_CLASS_DEFINITION: {
         auto *RD = cast<CXXRecordDecl>(D);
         UpdatedDeclContexts.insert(RD->getPrimaryContext());
         Record.push_back(RD->canPassInRegisters());
+        Record.push_back(RD->isParamDestroyedInCallee());
         Record.AddCXXDefinitionData(RD);
         Record.AddOffset(WriteDeclContextLexicalBlock(
             *Context, const_cast<CXXRecordDecl *>(RD)));
 
         // This state is sometimes updated by template instantiation, when we
         // switch from the specialization referring to the template declaration
         // to it referring to the template definition.
         if (auto *MSInfo = RD->getMemberSpecializationInfo()) {

lib/Serialization/ASTWriterDecl.cpp

void ASTDeclWriter::VisitRecordDecl(RecordDecl *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->isNonTrivialToPrimitiveDefaultInitialize());
   Record.push_back(D->isNonTrivialToPrimitiveCopy());
   Record.push_back(D->isNonTrivialToPrimitiveDestroy());
   Record.push_back(D->canPassInRegisters());
+  Record.push_back(D->isParamDestroyedInCallee());
 
   if (D->getDeclContext() == D->getLexicalDeclContext() &&
       !D->hasAttrs() &&
       !D->isImplicit() &&
       !D->isUsed(false) &&
       !D->hasExtInfo() &&
       !D->getTypedefNameForAnonDecl() &&
       D->getFirstDecl() == D->getMostRecentDecl() &&
void ASTWriter::WriteDeclAbbrevs() {
 
   // isNonTrivialToPrimitiveDefaultInitialize
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
   // isNonTrivialToPrimitiveCopy
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
   // isNonTrivialToPrimitiveDestroy
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // canPassInRegisters
+  // isParamDestroyedInCallee
+  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
 
   // 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>();

test/CodeGenCXX/microsoft-abi-sret-and-byval.cpp

 // FIXME: MSVC incompatible!
 // WOA: define dso_local arm_aapcs_vfpcc void @"?small_arg_with_dtor@@YAXUSmallWithDtor@@@Z"(%struct.SmallWithDtor* %s) {{.*}} {
 // WOA:   call arm_aapcs_vfpcc void @"??1SmallWithDtor@@QAA@XZ"(%struct.SmallWithDtor* %s)
 // WOA: }
 
 void call_small_arg_with_dtor() {
   small_arg_with_dtor(SmallWithDtor());
 }
-// The temporary is copied, so it's destroyed in the caller as well as the
-// callee.
 // WIN64-LABEL: define dso_local void @"?call_small_arg_with_dtor@@YAXXZ"()
 // WIN64:   call %struct.SmallWithDtor* @"??0SmallWithDtor@@QEAA@XZ"
 // WIN64:   call void @"?small_arg_with_dtor@@YAXUSmallWithDtor@@@Z"(i32 %{{.*}})
-// WIN64:   call void @"??1SmallWithDtor@@QEAA@XZ"
 // WIN64:   ret void
 
 // Test that references aren't destroyed in the callee.
 void ref_small_arg_with_dtor(const SmallWithDtor &s) { }
 // WIN32: define dso_local void @"?ref_small_arg_with_dtor@@YAXABUSmallWithDtor@@@Z"(%struct.SmallWithDtor* dereferenceable({{[0-9]+}}) %s) {{.*}} {
 // WIN32-NOT:   call x86_thiscallcc void @"??1SmallWithDtor@@QAE@XZ"
 // WIN32: }
 // WIN64-LABEL: define dso_local void @"?ref_small_arg_with_dtor@@YAXAEBUSmallWithDtor@@@Z"(%struct.SmallWithDtor* dereferenceable({{[0-9]+}}) %s)

test/CodeGenObjCXX/arc-special-member-functions.mm

void test_ObjCMember_copy_construct_destruct(ObjCMember m1) {
   ObjCMember m2 = m1;
   // CHECK: ret void
 }
 
 // CHECK-LABEL: define void @_Z27test_ObjCMember_copy_assign10ObjCMemberS_
 void test_ObjCMember_copy_assign(ObjCMember m1, ObjCMember m2) {
   // CHECK: {{call.*_ZN10ObjCMemberaSERKS_}}
   m1 = m2;
+  // CHECK-NEXT: call void @_ZN10ObjCMemberD1Ev(
+  // CHECK-NEXT: call void @_ZN10ObjCMemberD1Ev(
   // CHECK-NEXT: ret void
 }
 
 // Implicitly-generated copy assignment operator for ObjCMember
 // CHECK:    {{define linkonce_odr.*@_ZN10ObjCMemberaSERKS_}}
 // CHECK:      call void @objc_storeStrong
 // CHECK:      ret
 
void test_ObjCArrayMember_copy_construct_destruct(ObjCArrayMember m1) {
   ObjCArrayMember m2 = m1;
   // CHECK: call void @_ZN15ObjCArrayMemberD1Ev
   // CHECK: ret void
 }
 
 void test_ObjCArrayMember_copy_assign(ObjCArrayMember m1, ObjCArrayMember m2) {
   // CHECK: {{call.*@_ZN15ObjCArrayMemberaSERKS_}}
   m1 = m2;
+  // CHECK-NEXT: call void @_ZN15ObjCArrayMemberD1Ev(
+  // CHECK-NEXT: call void @_ZN15ObjCArrayMemberD1Ev(
   // CHECK-NEXT: ret void
 }
 
 // Implicitly-generated copy assignment operator for ObjCArrayMember
 // CHECK: {{define linkonce_odr.*@_ZN15ObjCArrayMemberaSERKS_}}
 // CHECK:      call void @objc_storeStrong
 // CHECK-NEXT: br label
 // CHECK: ret
 
 // CHECK-LABEL: define void @_Z47test_ObjCBlockMember_default_construct_destructv
 void test_ObjCBlockMember_default_construct_destruct() {
   // CHECK: call void @_ZN15ObjCBlockMemberC1Ev
   ObjCBlockMember m;
   // CHECK-NEXT: call void @_ZN15ObjCBlockMemberD1Ev
   // CHECK-NEXT: ret void
 }
 
 // CHECK-LABEL: define void @_Z44test_ObjCBlockMember_copy_construct_destruct15ObjCBlockMember
 void test_ObjCBlockMember_copy_construct_destruct(ObjCBlockMember m1) {
   // CHECK: call void @_ZN15ObjCBlockMemberC1ERKS_
   ObjCBlockMember m2 = m1;
-  // CHECK-NEXT: call void @_ZN15ObjCBlockMemberD1Ev
+  // CHECK-NEXT: call void @_ZN15ObjCBlockMemberD1Ev(
+  // CHECK-NEXT: call void @_ZN15ObjCBlockMemberD1Ev(
   // CHECK-NEXT: ret void
 }
 
 // CHECK-LABEL: define void @_Z32test_ObjCBlockMember_copy_assign15ObjCBlockMemberS_
 void test_ObjCBlockMember_copy_assign(ObjCBlockMember m1, ObjCBlockMember m2) {
   // CHECK: {{call.*_ZN15ObjCBlockMemberaSERKS_}}
   m1 = m2;
+  // CHECK-NEXT: call void @_ZN15ObjCBlockMemberD1Ev(
+  // CHECK-NEXT: call void @_ZN15ObjCBlockMemberD1Ev(
   // CHECK-NEXT: ret void
 }
 
 // Implicitly-generated copy assignment operator for ObjCBlockMember
 // CHECK:    define linkonce_odr dereferenceable({{[0-9]+}}) {{%.*}}* @_ZN15ObjCBlockMemberaSERKS_(
 // CHECK:      [[T0:%.*]] = getelementptr inbounds [[T:%.*]], [[T:%.*]]* {{%.*}}, i32 0, i32 0
 // CHECK-NEXT: [[T1:%.*]] = load i32 (i32)*, i32 (i32)** [[T0]], align 8
 // CHECK-NEXT: [[T2:%.*]] = bitcast i32 (i32)* [[T1]] to i8*

test/CodeGenObjCXX/objc-struct-cxx-abi.mm

 // RUN: %clang_cc1 -triple arm64-apple-ios11 -std=c++11 -fobjc-arc  -fobjc-weak -fobjc-runtime-has-weak -emit-llvm -o - %s | FileCheck %s
 // RUN: %clang_cc1 -triple arm64-apple-ios11 -std=c++11 -fobjc-arc  -fobjc-weak -fobjc-runtime-has-weak -fclang-abi-compat=4.0 -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple arm64-apple-ios11 -std=c++11 -fobjc-arc  -fobjc-weak -fobjc-runtime-has-weak -emit-llvm -o - -DTRIVIALABI %s | FileCheck %s
+// RUN: %clang_cc1 -triple arm64-apple-ios11 -std=c++11 -fobjc-arc  -fobjc-weak -fobjc-runtime-has-weak -fclang-abi-compat=4.0 -emit-llvm -o - -DTRIVIALABI %s | FileCheck %s
+
+// Check that structs consisting solely of __strong or __weak pointer fields are
+// destructed in the callee function and structs consisting solely of __strong
+// pointer fields are passed directly.
 
 // CHECK: %[[STRUCT_STRONGWEAK:.*]] = type { i8*, i8* }
 // CHECK: %[[STRUCT_STRONG:.*]] = type { i8* }
 // CHECK: %[[STRUCT_S:.*]] = type { i8* }
+// CHECK: %[[STRUCT_CONTAINSNONTRIVIAL:.*]] = type { %{{.*}}, i8* }
 
+#ifdef TRIVIALABI
 struct __attribute__((trivial_abi)) StrongWeak {
+#else
+struct StrongWeak {
+#endif
   id fstrong;
   __weak id fweak;
 };
 
+#ifdef TRIVIALABI
 struct __attribute__((trivial_abi)) Strong {
+#else
+struct Strong {
+#endif
   id fstrong;
 };
 
 template<class T>
+#ifdef TRIVIALABI
 struct __attribute__((trivial_abi)) S {
+#else
+struct S {
+#endif
   T a;
 };
 
+struct NonTrivial {
+  NonTrivial();
+  NonTrivial(const NonTrivial &);
+  ~NonTrivial();
+  int *a;
+};
+
+// This struct is not passed directly nor destructed in the callee because f0
+// has type NonTrivial.
+struct ContainsNonTrivial {
+  NonTrivial f0;
+  id f1;
+};
+
 // CHECK: define void @_Z19testParamStrongWeak10StrongWeak(%[[STRUCT_STRONGWEAK]]* %{{.*}})
-// CHECK-NOT: call
-// CHECK: ret void
+// CHECK: call %struct.StrongWeak* @_ZN10StrongWeakD1Ev(
+// CHECK-NEXT: ret void
 
 void testParamStrongWeak(StrongWeak a) {
 }
 
 // CHECK: define void @_Z18testCallStrongWeakP10StrongWeak(%[[STRUCT_STRONGWEAK]]* %[[A:.*]])
 // CHECK: %[[A_ADDR:.*]] = alloca %[[STRUCT_STRONGWEAK]]*, align 8
 // CHECK: %[[AGG_TMP:.*]] = alloca %[[STRUCT_STRONGWEAK]], align 8
 // CHECK: store %[[STRUCT_STRONGWEAK]]* %[[A]], %[[STRUCT_STRONGWEAK]]** %[[A_ADDR]], align 8
 // CHECK: %[[V0:.*]] = load %[[STRUCT_STRONGWEAK]]*, %[[STRUCT_STRONGWEAK]]** %[[A_ADDR]], align 8
 // CHECK: %[[CALL:.*]] = call %[[STRUCT_STRONGWEAK]]* @_ZN10StrongWeakC1ERKS_(%[[STRUCT_STRONGWEAK]]* %[[AGG_TMP]], %[[STRUCT_STRONGWEAK]]* dereferenceable(16) %[[V0]])
 // CHECK: call void @_Z19testParamStrongWeak10StrongWeak(%[[STRUCT_STRONGWEAK]]* %[[AGG_TMP]])
-// CHECK: %[[CALL1:.*]] = call %[[STRUCT_STRONGWEAK]]* @_ZN10StrongWeakD1Ev(%[[STRUCT_STRONGWEAK]]* %[[AGG_TMP]])
+// CHECK-NOT: call
 // CHECK: ret void
 
 void testCallStrongWeak(StrongWeak *a) {
   testParamStrongWeak(*a);
 }
 
 // CHECK: define void @_Z20testReturnStrongWeakP10StrongWeak(%[[STRUCT_STRONGWEAK:.*]]* noalias sret %[[AGG_RESULT:.*]], %[[STRUCT_STRONGWEAK]]* %[[A:.*]])
 // CHECK: %[[A_ADDR:.*]] = alloca %[[STRUCT_STRONGWEAK]]*, align 8

 // CHECK: %[[COERCE_VAL_PI:.*]] = ptrtoint i8* %[[V1]] to i64
 // CHECK: ret i64 %[[COERCE_VAL_PI]]
 
 Strong testReturnStrong(Strong *a) {
   return *a;
 }
 
 // CHECK: define void @_Z21testParamWeakTemplate1SIU6__weakP11objc_objectE(%[[STRUCT_S]]* %{{.*}})
+// CHECK: call %struct.S* @_ZN1SIU6__weakP11objc_objectED1Ev(
+// CHECK-NEXT: ret void
+
+void testParamWeakTemplate(S<__weak id> a) {
+}
+
+// CHECK: define void @_Z27testParamContainsNonTrivial18ContainsNonTrivial(%[[STRUCT_CONTAINSNONTRIVIAL]]* %{{.*}})
 // CHECK-NOT: call
 // CHECK: ret void
 
-void testParamWeakTemplate(S<__weak id> a) {
+void testParamContainsNonTrivial(ContainsNonTrivial a) {
+}
+
+// CHECK: define void @_Z26testCallContainsNonTrivialP18ContainsNonTrivial(
+// CHECK: call void @_Z27testParamContainsNonTrivial18ContainsNonTrivial(%[[STRUCT_CONTAINSNONTRIVIAL]]* %{{.*}})
+// CHECK: call %struct.ContainsNonTrivial* @_ZN18ContainsNonTrivialD1Ev(%[[STRUCT_CONTAINSNONTRIVIAL]]* %{{.*}})
+
+void testCallContainsNonTrivial(ContainsNonTrivial *a) {
+  testParamContainsNonTrivial(*a);
 }

test/CodeGenObjCXX/property-dot-copy-elision.mm

 // RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -std=c++1z -fobjc-arc -o - %s | FileCheck %s
 
 struct S0 {
+  ~S0();
   id f;
 };
 
 struct S1 {
   S1();
+  ~S1();
   S1(S0);
   id f;
 };
 
 @interface C
 @property S1 f;
 @end
 @implementation C