re-roll-forward "[clang] Mark `trivial_abi` types as "trivially relocatable"".""

[devin.jeanpierre]

Summary

This reverts commit b0bc93da926a943cdc2d8b04f8dcbe23a774520c.

Changes: s/_WIN32/_WIN64/g in clang/test/SemaCXX/attr-trivial-abi.cpp.

The calling convention is specific to 64-bit windows. It's even in the name: CCK_MicrosoftWin64.

After this, the test passes with both -triple i686-pc-win32 and -triple x86_64-pc-win32. Phew!

clang/docs/LanguageExtensions.rst

* ``__is_signed`` (C++, Embarcadero):
   types. Note, before Clang 10, returned true for enumeration types if the
   underlying type was signed, and returned false for floating-point types.
 * ``__is_standard_layout`` (C++, GNU, Microsoft, Embarcadero)
 * ``__is_trivial`` (C++, GNU, Microsoft, Embarcadero)
 * ``__is_trivially_assignable`` (C++, GNU, Microsoft)
 * ``__is_trivially_constructible`` (C++, GNU, Microsoft)
 * ``__is_trivially_copyable`` (C++, GNU, Microsoft)
 * ``__is_trivially_destructible`` (C++, MSVC 2013)
+* ``__is_trivially_relocatable`` (Clang): Returns true if moving an object
+  of the given type, and then destroying the source object, is known to be
+  functionally equivalent to copying the underlying bytes and then dropping the
+  source object on the floor. This is true of trivial types and types which
+  were made trivially relocatable via the ``clang::trivial_abi`` attribute.
 * ``__is_union`` (C++, GNU, Microsoft, Embarcadero)
 * ``__is_unsigned`` (C++, Embarcadero):
   Returns false for enumeration types. Note, before Clang 13, returned true for
   enumeration types if the underlying type was unsigned.
 * ``__is_void`` (C++, Embarcadero)
 * ``__is_volatile`` (C++, Embarcadero)
 * ``__reference_binds_to_temporary(T, U)`` (Clang):  Determines whether a
   reference of type ``T`` bound to an expression of type ``U`` would bind to a

clang/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;
 
+  /// Return true if this is a trivially relocatable type.
+  bool isTriviallyRelocatableType(const ASTContext &Context) const;
 
   /// Returns true if it is a class and it might be dynamic.
   bool mayBeDynamicClass() const;
 
   /// Returns true if it is not a class or if the class might not be dynamic.
   bool mayBeNotDynamicClass() const;
 
   // Don't promise in the API that anything besides 'const' can be

clang/include/clang/Basic/AttrDocs.td

.. code-block:: c++
     struct B {
       A a;
     };
 
 If a type is trivial for the purposes of calls, has a non-trivial destructor,
 and is passed as an argument by value, the convention is that the callee will
 destroy the object before returning.
 
+If a type is trivial for the purpose of calls, it is assumed to be trivially
+relocatable for the purpose of ``__is_trivially_relocatable``.
+
 Attribute ``trivial_abi`` has no effect in the following cases:
 
 - The class directly declares a virtual base or virtual methods.
 - Copy constructors and move constructors of the class are all deleted.
 - The class has a base class that is non-trivial for the purposes of calls.
 - The class has a non-static data member whose type is non-trivial for the
   purposes of calls, which includes:
 

clang/include/clang/Basic/TokenKinds.def

 TYPE_TRAIT_N(__is_trivially_constructible, IsTriviallyConstructible, KEYCXX)
 TYPE_TRAIT_1(__is_trivially_copyable, IsTriviallyCopyable, KEYCXX)
 TYPE_TRAIT_1(__is_union, IsUnion, KEYCXX)
 TYPE_TRAIT_1(__has_unique_object_representations,
              HasUniqueObjectRepresentations, KEYCXX)
 KEYWORD(__underlying_type           , KEYCXX)
 
 // Clang-only C++ Type Traits
+TYPE_TRAIT_1(__is_trivially_relocatable, IsTriviallyRelocatable, KEYCXX)
 TYPE_TRAIT_2(__reference_binds_to_temporary, ReferenceBindsToTemporary, KEYCXX)
 
 // Embarcadero Expression Traits
 EXPRESSION_TRAIT(__is_lvalue_expr, IsLValueExpr, KEYCXX)
 EXPRESSION_TRAIT(__is_rvalue_expr, IsRValueExpr, KEYCXX)
 
 // Embarcadero Unary Type Traits
 TYPE_TRAIT_1(__is_arithmetic, IsArithmetic, KEYCXX)

clang/lib/AST/Type.cpp

if (const auto *RT = CanonicalType->getAs<RecordType>()) {
 
     return true;
   }
 
   // No other types can match.
   return false;
 }
 
+bool QualType::isTriviallyRelocatableType(const ASTContext &Context) const {
+  QualType BaseElementType = Context.getBaseElementType(*this);
+
+  if (BaseElementType->isIncompleteType()) {
+    return false;
+  } else if (const auto *RD = BaseElementType->getAsRecordDecl()) {
+    return RD->canPassInRegisters();
+  } else {
+    switch (isNonTrivialToPrimitiveDestructiveMove()) {
+    case PCK_Trivial:
+      return !isDestructedType();
+    case PCK_ARCStrong:
+      return true;
+    default:
+      return false;
+    }
+  }
+}
+
 bool QualType::isNonWeakInMRRWithObjCWeak(const ASTContext &Context) const {
   return !Context.getLangOpts().ObjCAutoRefCount &&
          Context.getLangOpts().ObjCWeak &&
          getObjCLifetime() != Qualifiers::OCL_Weak;
 }
 
 bool QualType::hasNonTrivialToPrimitiveDefaultInitializeCUnion(const RecordDecl *RD) {
   return RD->hasNonTrivialToPrimitiveDefaultInitializeCUnion();

clang/lib/Sema/SemaExprCXX.cpp

 //===--- SemaExprCXX.cpp - Semantic Analysis for Expressions --------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
 /// Implements semantic analysis for C++ expressions.
 ///
 //===----------------------------------------------------------------------===//
 
-#include "clang/Sema/Template.h"
-#include "clang/Sema/SemaInternal.h"
 #include "TreeTransform.h"
 #include "TypeLocBuilder.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/ASTLambda.h"
 #include "clang/AST/CXXInheritance.h"
 #include "clang/AST/CharUnits.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/ExprCXX.h"
 #include "clang/AST/ExprObjC.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/AST/TypeLoc.h"
 #include "clang/Basic/AlignedAllocation.h"
 #include "clang/Basic/PartialDiagnostic.h"
 #include "clang/Basic/TargetInfo.h"
+#include "clang/Basic/TypeTraits.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Sema/DeclSpec.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/ParsedTemplate.h"
 #include "clang/Sema/Scope.h"
 #include "clang/Sema/ScopeInfo.h"
+#include "clang/Sema/SemaInternal.h"
 #include "clang/Sema/SemaLambda.h"
+#include "clang/Sema/Template.h"
 #include "clang/Sema/TemplateDeduction.h"
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/ErrorHandling.h"
 using namespace clang;
 using namespace sema;
 
 /// Handle the result of the special case name lookup for inheriting
static bool CheckUnaryTypeTraitTypeCompleteness(Sema &S, TypeTrait UTT,
   // C++1z [meta.unary.prop]:
   //   remove_all_extents_t<T> shall be a complete type or cv void.
   case UTT_IsAggregate:
   case UTT_IsTrivial:
   case UTT_IsTriviallyCopyable:
   case UTT_IsStandardLayout:
   case UTT_IsPOD:
   case UTT_IsLiteral:
+  // By analogy, is_trivially_relocatable imposes the same constraints.
+  case UTT_IsTriviallyRelocatable:
   // Per the GCC type traits documentation, T shall be a complete type, cv void,
   // or an array of unknown bound. But GCC actually imposes the same constraints
   // as above.
   case UTT_HasNothrowAssign:
   case UTT_HasNothrowMoveAssign:
   case UTT_HasNothrowConstructor:
   case UTT_HasNothrowCopy:
   case UTT_HasTrivialAssign:
case UTT_HasVirtualDestructor:
     //   http://docwiki.embarcadero.com/RADStudio/XE/en/Type_Trait_Functions_(C%2B%2B0x)_Index
   case UTT_IsCompleteType:
     // http://docwiki.embarcadero.com/RADStudio/XE/en/Is_complete_type_(typename_T_):
     //   Returns True if and only if T is a complete type at the point of the
     //   function call.
     return !T->isIncompleteType();
   case UTT_HasUniqueObjectRepresentations:
     return C.hasUniqueObjectRepresentations(T);
+  case UTT_IsTriviallyRelocatable:
+    return T.isTriviallyRelocatableType(C);
   }
 }
 
 static bool EvaluateBinaryTypeTrait(Sema &Self, TypeTrait BTT, QualType LhsT,
                                     QualType RhsT, SourceLocation KeyLoc);
 
 static bool evaluateTypeTrait(Sema &S, TypeTrait Kind, SourceLocation KWLoc,
                               ArrayRef<TypeSourceInfo *> Args,

clang/test/SemaCXX/attr-trivial-abi.cpp

 // RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++11
 
 void __attribute__((trivial_abi)) foo(); // expected-warning {{'trivial_abi' attribute only applies to classes}}
 
 // Should not crash.
 template <class>
 class __attribute__((trivial_abi)) a { a(a &&); };
+#ifdef _WIN64
+// On Windows, to be trivial-for-calls, an object must be trivially copyable.
+// (And it is only trivially relocatable, currently, if it is trivial for calls.)
+// In this case, it is suppressed by an explicitly defined move constructor.
+// Similar concerns apply to later tests that have #ifdef _WIN64.
+static_assert(!__is_trivially_relocatable(a<int>), "");
+#else
+static_assert(__is_trivially_relocatable(a<int>), "");
+#endif
 
 struct [[clang::trivial_abi]] S0 {
   int a;
 };
+static_assert(__is_trivially_relocatable(S0), "");
 
 struct __attribute__((trivial_abi)) S1 {
   int a;
 };
+static_assert(__is_trivially_relocatable(S1), "");
 
 struct __attribute__((trivial_abi)) S3 { // expected-warning {{'trivial_abi' cannot be applied to 'S3'}} expected-note {{is polymorphic}}
   virtual void m();
 };
+static_assert(!__is_trivially_relocatable(S3), "");
 
 struct S3_2 {
   virtual void m();
 } __attribute__((trivial_abi)); // expected-warning {{'trivial_abi' cannot be applied to 'S3_2'}} expected-note {{is polymorphic}}
+static_assert(!__is_trivially_relocatable(S3_2), "");
 
 struct __attribute__((trivial_abi)) S3_3 { // expected-warning {{'trivial_abi' cannot be applied to 'S3_3'}} expected-note {{has a field of a non-trivial class type}}
   S3_3(S3_3 &&);
   S3_2 s32;
 };
+#ifdef __ORBIS__
+// The ClangABI4OrPS4 calling convention kind passes classes in registers if the
+// copy constructor is trivial for calls *or deleted*, while other platforms do
+// not accept deleted constructors.
+static_assert(__is_trivially_relocatable(S3_3), "");
+#else
+static_assert(!__is_trivially_relocatable(S3_3), "");
+#endif
 
 // Diagnose invalid trivial_abi even when the type is templated because it has a non-trivial field.
 template <class T>
 struct __attribute__((trivial_abi)) S3_4 { // expected-warning {{'trivial_abi' cannot be applied to 'S3_4'}} expected-note {{has a field of a non-trivial class type}}
   S3_4(S3_4 &&);
   S3_2 s32;
 };
+static_assert(!__is_trivially_relocatable(S3_4<int>), "");
 
 struct S4 {
   int a;
 };
+static_assert(__is_trivially_relocatable(S4), "");
 
 struct __attribute__((trivial_abi)) S5 : public virtual S4 { // expected-warning {{'trivial_abi' cannot be applied to 'S5'}} expected-note {{has a virtual base}}
 };
+static_assert(!__is_trivially_relocatable(S5), "");
 
 struct __attribute__((trivial_abi)) S9 : public S4 {
 };
+static_assert(__is_trivially_relocatable(S9), "");
 
 struct __attribute__((trivial_abi(1))) S8 { // expected-error {{'trivial_abi' attribute takes no arguments}}
   int a;
 };
 
 // Do not warn about deleted ctors  when 'trivial_abi' is used to annotate a template class.
 template <class T>
 struct __attribute__((trivial_abi)) S10 {
   T p;
 };
 
 S10<int *> p1;
+static_assert(__is_trivially_relocatable(S10<int>), "");
+static_assert(!__is_trivially_relocatable(S10<S3>), "");
 
 template <class T>
 struct S14 {
   T a;
 };
 
 template <class T>
 struct __attribute__((trivial_abi)) S15 : S14<T> {
 };
 
 S15<int> s15;
+static_assert(__is_trivially_relocatable(S15<int>), "");
+static_assert(!__is_trivially_relocatable(S15<S3>), "");
 
 template <class T>
 struct __attribute__((trivial_abi)) S16 {
   S14<T> a;
 };
+static_assert(__is_trivially_relocatable(S16<int>), "");
+static_assert(!__is_trivially_relocatable(S16<S3>), "");
 
 S16<int> s16;
 
 template <class T>
 struct __attribute__((trivial_abi)) S17 {
 };
 
 S17<int> s17;
+static_assert(__is_trivially_relocatable(S17<int>), "");
+static_assert(__is_trivially_relocatable(S17<S3>), "");
 
 namespace deletedCopyMoveConstructor {
 struct __attribute__((trivial_abi)) CopyMoveDeleted { // expected-warning {{'trivial_abi' cannot be applied to 'CopyMoveDeleted'}} expected-note {{copy constructors and move constructors are all deleted}}
   CopyMoveDeleted(const CopyMoveDeleted &) = delete;
   CopyMoveDeleted(CopyMoveDeleted &&) = delete;
 };
+#ifdef __ORBIS__
+static_assert(__is_trivially_relocatable(CopyMoveDeleted), "");
+#else
+static_assert(!__is_trivially_relocatable(CopyMoveDeleted), "");
+#endif
 
 struct __attribute__((trivial_abi)) S18 { // expected-warning {{'trivial_abi' cannot be applied to 'S18'}} expected-note {{copy constructors and move constructors are all deleted}}
   CopyMoveDeleted a;
 };
+#ifdef __ORBIS__
+static_assert(__is_trivially_relocatable(S18), "");
+#else
+static_assert(!__is_trivially_relocatable(S18), "");
+#endif
 
 struct __attribute__((trivial_abi)) CopyDeleted {
   CopyDeleted(const CopyDeleted &) = delete;
   CopyDeleted(CopyDeleted &&) = default;
 };
+#ifdef _WIN64
+static_assert(!__is_trivially_relocatable(CopyDeleted), "");
+#else
+static_assert(__is_trivially_relocatable(CopyDeleted), "");
+#endif
 
 struct __attribute__((trivial_abi)) MoveDeleted {
   MoveDeleted(const MoveDeleted &) = default;
   MoveDeleted(MoveDeleted &&) = delete;
 };
+static_assert(__is_trivially_relocatable(MoveDeleted), "");
 
 struct __attribute__((trivial_abi)) S19 { // expected-warning {{'trivial_abi' cannot be applied to 'S19'}} expected-note {{copy constructors and move constructors are all deleted}}
   CopyDeleted a;
   MoveDeleted b;
 };
+#ifdef __ORBIS__
+static_assert(__is_trivially_relocatable(S19), "");
+#else
+static_assert(!__is_trivially_relocatable(S19), "");
+#endif
 
 // This is fine since the move constructor isn't deleted.
 struct __attribute__((trivial_abi)) S20 {
   int &&a; // a member of rvalue reference type deletes the copy constructor.
 };
+#ifdef _WIN64
+static_assert(!__is_trivially_relocatable(S20), "");
+#else
+static_assert(__is_trivially_relocatable(S20), "");
+#endif
 } // namespace deletedCopyMoveConstructor

clang/test/SemaCXX/type-traits.cpp

 #undef T16
 #undef T64
 #undef T256
 #undef T1024
 #undef T4096
 #undef T16384
 #undef T32768
 } // namespace type_trait_expr_numargs_overflow
+
+namespace is_trivially_relocatable {
+
+static_assert(!__is_trivially_relocatable(void), "");
+static_assert(__is_trivially_relocatable(int), "");
+static_assert(__is_trivially_relocatable(int[]), "");
+
+enum Enum {};
+static_assert(__is_trivially_relocatable(Enum), "");
+static_assert(__is_trivially_relocatable(Enum[]), "");
+
+union Union {int x;};
+static_assert(__is_trivially_relocatable(Union), "");
+static_assert(__is_trivially_relocatable(Union[]), "");
+
+struct Trivial {};
+static_assert(__is_trivially_relocatable(Trivial), "");
+static_assert(__is_trivially_relocatable(Trivial[]), "");
+
+struct Incomplete; // expected-note {{forward declaration of 'is_trivially_relocatable::Incomplete'}}
+bool unused = __is_trivially_relocatable(Incomplete); // expected-error {{incomplete type}}
+
+struct NontrivialDtor {
+  ~NontrivialDtor() {}
+};
+static_assert(!__is_trivially_relocatable(NontrivialDtor), "");
+static_assert(!__is_trivially_relocatable(NontrivialDtor[]), "");
+
+struct NontrivialCopyCtor {
+  NontrivialCopyCtor(const NontrivialCopyCtor&) {}
+};
+static_assert(!__is_trivially_relocatable(NontrivialCopyCtor), "");
+static_assert(!__is_trivially_relocatable(NontrivialCopyCtor[]), "");
+
+struct NontrivialMoveCtor {
+  NontrivialMoveCtor(NontrivialMoveCtor&&) {}
+};
+static_assert(!__is_trivially_relocatable(NontrivialMoveCtor), "");
+static_assert(!__is_trivially_relocatable(NontrivialMoveCtor[]), "");
+
+struct [[clang::trivial_abi]] TrivialAbiNontrivialDtor {
+  ~TrivialAbiNontrivialDtor() {}
+};
+static_assert(__is_trivially_relocatable(TrivialAbiNontrivialDtor), "");
+static_assert(__is_trivially_relocatable(TrivialAbiNontrivialDtor[]), "");
+
+struct [[clang::trivial_abi]] TrivialAbiNontrivialCopyCtor {
+  TrivialAbiNontrivialCopyCtor(const TrivialAbiNontrivialCopyCtor&) {}
+};
+static_assert(__is_trivially_relocatable(TrivialAbiNontrivialCopyCtor), "");
+static_assert(__is_trivially_relocatable(TrivialAbiNontrivialCopyCtor[]), "");
+
+// A more complete set of tests for the behavior of trivial_abi can be found in
+// clang/test/SemaCXX/attr-trivial-abi.cpp
+struct [[clang::trivial_abi]] TrivialAbiNontrivialMoveCtor {
+  TrivialAbiNontrivialMoveCtor(TrivialAbiNontrivialMoveCtor&&) {}
+};
+static_assert(__is_trivially_relocatable(TrivialAbiNontrivialMoveCtor), "");
+static_assert(__is_trivially_relocatable(TrivialAbiNontrivialMoveCtor[]), "");
+
+} // namespace is_trivially_relocatable

clang/test/SemaObjCXX/arc-type-traits.mm

 // RUN: %clang_cc1 -fsyntax-only -fobjc-arc -fobjc-runtime-has-weak -verify -std=c++11 %s
 // expected-no-diagnostics
 
 // Check the results of the various type-trait query functions on
 // lifetime-qualified types in ARC.
 
 #define JOIN3(X,Y) X ## Y
 #define JOIN2(X,Y) JOIN3(X,Y)
 #define JOIN(X,Y) JOIN2(X,Y)
 
 #define TRAIT_IS_TRUE(Trait, Type) char JOIN2(Trait,__LINE__)[Trait(Type)? 1 : -1]
 #define TRAIT_IS_FALSE(Trait, Type) char JOIN2(Trait,__LINE__)[Trait(Type)? -1 : 1]
 #define TRAIT_IS_TRUE_2(Trait, Type1, Type2) char JOIN2(Trait,__LINE__)[Trait(Type1, Type2)? 1 : -1]
 #define TRAIT_IS_FALSE_2(Trait, Type1, Type2) char JOIN2(Trait,__LINE__)[Trait(Type1, Type2)? -1 : 1]
-  
 struct HasStrong { id obj; };
 struct HasWeak { __weak id obj; };
 struct HasUnsafeUnretained { __unsafe_unretained id obj; };
 
 // __has_nothrow_assign
 TRAIT_IS_TRUE(__has_nothrow_assign, __strong id);
 TRAIT_IS_TRUE(__has_nothrow_assign, __weak id);
 TRAIT_IS_TRUE(__has_nothrow_assign, __autoreleasing id);

 
 TRAIT_IS_FALSE_2(__is_trivially_constructible, HasStrong, HasStrong);
 TRAIT_IS_FALSE_2(__is_trivially_constructible, HasStrong, HasStrong&&);
 TRAIT_IS_FALSE_2(__is_trivially_constructible, HasWeak, HasWeak);
 TRAIT_IS_FALSE_2(__is_trivially_constructible, HasWeak, HasWeak&&);
 TRAIT_IS_TRUE_2(__is_trivially_constructible, HasUnsafeUnretained, HasUnsafeUnretained);
 TRAIT_IS_TRUE_2(__is_trivially_constructible, HasUnsafeUnretained, HasUnsafeUnretained&&);
 
+// __is_trivially_relocatable
+TRAIT_IS_TRUE(__is_trivially_relocatable, __strong id);
+TRAIT_IS_FALSE(__is_trivially_relocatable, __weak id);
+TRAIT_IS_TRUE(__is_trivially_relocatable, __autoreleasing id);
+TRAIT_IS_TRUE(__is_trivially_relocatable, __unsafe_unretained id);
+TRAIT_IS_TRUE(__is_trivially_relocatable, HasStrong);
+TRAIT_IS_FALSE(__is_trivially_relocatable, HasWeak);
+TRAIT_IS_TRUE(__is_trivially_relocatable, HasUnsafeUnretained);

clang/test/SemaObjCXX/objc-weak-type-traits.mm

 // RUN: %clang_cc1 -fsyntax-only -fobjc-weak -fobjc-runtime-has-weak -verify -std=c++11 %s
 // expected-no-diagnostics
 
 // Check the results of the various type-trait query functions on
 // lifetime-qualified types in ObjC Weak.
 
 #define TRAIT_IS_TRUE(Trait, Type) static_assert(Trait(Type), "")
 #define TRAIT_IS_FALSE(Trait, Type) static_assert(!Trait(Type), "")
 #define TRAIT_IS_TRUE_2(Trait, Type1, Type2) static_assert(Trait(Type1, Type2), "")
 #define TRAIT_IS_FALSE_2(Trait, Type1, Type2) static_assert(!Trait(Type1, Type2), "")
-  
 struct HasStrong { id obj; };
 struct HasWeak { __weak id obj; };
 struct HasUnsafeUnretained { __unsafe_unretained id obj; };
 
 // __has_nothrow_assign
 TRAIT_IS_TRUE(__has_nothrow_assign, __strong id);
 TRAIT_IS_TRUE(__has_nothrow_assign, __weak id);
 TRAIT_IS_TRUE(__has_nothrow_assign, __autoreleasing id);

 TRAIT_IS_TRUE_2(__is_trivially_constructible, __unsafe_unretained id, __unsafe_unretained id&&);
 
 TRAIT_IS_TRUE_2(__is_trivially_constructible, HasStrong, HasStrong);
 TRAIT_IS_TRUE_2(__is_trivially_constructible, HasStrong, HasStrong&&);
 TRAIT_IS_FALSE_2(__is_trivially_constructible, HasWeak, HasWeak);
 TRAIT_IS_FALSE_2(__is_trivially_constructible, HasWeak, HasWeak&&);
 TRAIT_IS_TRUE_2(__is_trivially_constructible, HasUnsafeUnretained, HasUnsafeUnretained);
 TRAIT_IS_TRUE_2(__is_trivially_constructible, HasUnsafeUnretained, HasUnsafeUnretained&&);
+
+// __is_trivially_relocatable
+TRAIT_IS_TRUE(__is_trivially_relocatable, __strong id);
+TRAIT_IS_FALSE(__is_trivially_relocatable, __weak id);
+TRAIT_IS_TRUE(__is_trivially_relocatable, __autoreleasing id);
+TRAIT_IS_TRUE(__is_trivially_relocatable, __unsafe_unretained id);
+TRAIT_IS_TRUE(__is_trivially_relocatable, HasStrong);
+TRAIT_IS_FALSE(__is_trivially_relocatable, HasWeak);
+TRAIT_IS_TRUE(__is_trivially_relocatable, HasUnsafeUnretained);