Add support for attribute 'trivial_abi'.

The 'trivial_abi' attribute can be applied to a C++ class, struct, or
union. It makes special functions of the annotated class (the destructor
and copy/move constructors) to be trivial for the purpose of calls and,
as a result, enables the annotated class or containing classes to be
passed or returned using the C ABI for the underlying type.

When a type that is considered trivial for the purpose of calls despite
having a non-trivial destructor (which happens only when the class type
or one of its subobjects is a 'trivial_abi' class) is passed to a
function, the callee is responsible for destroying the object.

For more background, see the discussions that took place on the mailing
list:

http://lists.llvm.org/pipermail/cfe-dev/2017-November/055955.html
http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20180101/thread.html#214043

rdar://problem/35204524

Differential Revision: https://reviews.llvm.org/D41039

llvm-svn: 324269

4 files changed, 438 insertions, 1 deletions

diff --git a/clang/test/CodeGenCXX/trivial_abi.cpp b/clang/test/CodeGenCXX/trivial_abi.cpp
new file mode 100644
index 00000000000..2cf07b22581
--- /dev/null
+++ b/clang/test/CodeGenCXX/trivial_abi.cpp
@@ -0,0 +1,239 @@
+// RUN: %clang_cc1 -triple arm64-apple-ios11 -std=c++11 -fcxx-exceptions -fexceptions -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple arm64-apple-ios11 -std=c++11 -fcxx-exceptions -fexceptions -fclang-abi-compat=4.0 -emit-llvm -o - %s | FileCheck %s
+
+// CHECK: %[[STRUCT_SMALL:.*]] = type { i32* }
+// CHECK: %[[STRUCT_LARGE:.*]] = type { i32*, [128 x i32] }
+// CHECK: %[[STRUCT_TRIVIAL:.*]] = type { i32 }
+// CHECK: %[[STRUCT_NONTRIVIAL:.*]] = type { i32 }
+
+struct __attribute__((trivial_abi)) Small {
+  int *p;
+  Small();
+  ~Small();
+  Small(const Small &) noexcept;
+  Small &operator=(const Small &);
+};
+
+struct __attribute__((trivial_abi)) Large {
+  int *p;
+  int a[128];
+  Large();
+  ~Large();
+  Large(const Large &) noexcept;
+  Large &operator=(const Large &);
+};
+
+struct Trivial {
+  int a;
+};
+
+struct NonTrivial {
+  NonTrivial();
+  ~NonTrivial();
+  int a;
+};
+
+struct HasTrivial {
+  Small s;
+  Trivial m;
+};
+
+struct HasNonTrivial {
+  Small s;
+  NonTrivial m;
+};
+
+// CHECK: define void @_Z14testParamSmall5Small(i64 %[[A_COERCE:.*]])
+// CHECK: %[[A:.*]] = alloca %[[STRUCT_SMALL]], align 8
+// CHECK: %[[COERCE_DIVE:.*]] = getelementptr inbounds %[[STRUCT_SMALL]], %[[STRUCT_SMALL]]* %[[A]], i32 0, i32 0
+// CHECK: %[[COERCE_VAL_IP:.*]] = inttoptr i64 %[[A_COERCE]] to i32*
+// CHECK: store i32* %[[COERCE_VAL_IP]], i32** %[[COERCE_DIVE]], align 8
+// CHECK: %[[CALL:.*]] = call %[[STRUCT_SMALL]]* @_ZN5SmallD1Ev(%[[STRUCT_SMALL]]* %[[A]])
+// CHECK: ret void
+// CHECK: }
+
+void testParamSmall(Small a) noexcept {
+}
+
+// CHECK: define i64 @_Z15testReturnSmallv()
+// CHECK: %[[RETVAL:.*]] = alloca %[[STRUCT_SMALL:.*]], align 8
+// CHECK: %[[CALL:.*]] = call %[[STRUCT_SMALL]]* @_ZN5SmallC1Ev(%[[STRUCT_SMALL]]* %[[RETVAL]])
+// CHECK: %[[COERCE_DIVE:.*]] = getelementptr inbounds %[[STRUCT_SMALL]], %[[STRUCT_SMALL]]* %[[RETVAL]], i32 0, i32 0
+// CHECK: %[[V0:.*]] = load i32*, i32** %[[COERCE_DIVE]], align 8
+// CHECK: %[[COERCE_VAL_PI:.*]] = ptrtoint i32* %[[V0]] to i64
+// CHECK: ret i64 %[[COERCE_VAL_PI]]
+// CHECK: }
+
+Small testReturnSmall() {
+  Small t;
+  return t;
+}
+
+// CHECK: define void @_Z14testCallSmall0v()
+// CHECK: %[[T:.*]] = alloca %[[STRUCT_SMALL:.*]], align 8
+// CHECK: %[[AGG_TMP:.*]] = alloca %[[STRUCT_SMALL]], align 8
+// CHECK: %[[CALL:.*]] = call %[[STRUCT_SMALL]]* @_ZN5SmallC1Ev(%[[STRUCT_SMALL]]* %[[T]])
+// CHECK: %[[CALL1:.*]] = call %[[STRUCT_SMALL]]* @_ZN5SmallC1ERKS_(%[[STRUCT_SMALL]]* %[[AGG_TMP]], %[[STRUCT_SMALL]]* dereferenceable(8) %[[T]])
+// CHECK: %[[COERCE_DIVE:.*]] = getelementptr inbounds %[[STRUCT_SMALL]], %[[STRUCT_SMALL]]* %[[AGG_TMP]], i32 0, i32 0
+// CHECK: %[[V0:.*]] = load i32*, i32** %[[COERCE_DIVE]], align 8
+// CHECK: %[[COERCE_VAL_PI:.*]] = ptrtoint i32* %[[V0]] to i64
+// CHECK: call void @_Z14testParamSmall5Small(i64 %[[COERCE_VAL_PI]])
+// CHECK: %[[CALL2:.*]] = call %[[STRUCT_SMALL]]* @_ZN5SmallD1Ev(%[[STRUCT_SMALL]]* %[[T]])
+// CHECK: ret void
+// CHECK: }
+
+void testCallSmall0() {
+  Small t;
+  testParamSmall(t);
+}
+
+// CHECK: define void @_Z14testCallSmall1v()
+// CHECK: %[[AGG_TMP:.*]] = alloca %[[STRUCT_SMALL:.*]], align 8
+// CHECK: %[[CALL:.*]] = call i64 @_Z15testReturnSmallv()
+// CHECK: %[[COERCE_DIVE:.*]] = getelementptr inbounds %[[STRUCT_SMALL]], %[[STRUCT_SMALL]]* %[[AGG_TMP]], i32 0, i32 0
+// CHECK: %[[COERCE_VAL_IP:.*]] = inttoptr i64 %[[CALL]] to i32*
+// CHECK: store i32* %[[COERCE_VAL_IP]], i32** %[[COERCE_DIVE]], align 8
+// CHECK: %[[COERCE_DIVE1:.*]] = getelementptr inbounds %[[STRUCT_SMALL]], %[[STRUCT_SMALL]]* %[[AGG_TMP]], i32 0, i32 0
+// CHECK: %[[V0:.*]] = load i32*, i32** %[[COERCE_DIVE1]], align 8
+// CHECK: %[[COERCE_VAL_PI:.*]] = ptrtoint i32* %[[V0]] to i64
+// CHECK: call void @_Z14testParamSmall5Small(i64 %[[COERCE_VAL_PI]])
+// CHECK: ret void
+// CHECK: }
+
+void testCallSmall1() {
+  testParamSmall(testReturnSmall());
+}
+
+// CHECK: define void @_Z16testIgnoredSmallv()
+// CHECK: %[[AGG_TMP_ENSURED:.*]] = alloca %[[STRUCT_SMALL:.*]], align 8
+// CHECK: %[[CALL:.*]] = call i64 @_Z15testReturnSmallv()
+// CHECK: %[[COERCE_DIVE:.*]] = getelementptr inbounds %[[STRUCT_SMALL]], %[[STRUCT_SMALL]]* %[[AGG_TMP_ENSURED]], i32 0, i32 0
+// CHECK: %[[COERCE_VAL_IP:.*]] = inttoptr i64 %[[CALL]] to i32*
+// CHECK: store i32* %[[COERCE_VAL_IP]], i32** %[[COERCE_DIVE]], align 8
+// CHECK: %[[CALL1:.*]] = call %[[STRUCT_SMALL]]* @_ZN5SmallD1Ev(%[[STRUCT_SMALL]]* %[[AGG_TMP_ENSURED]])
+// CHECK: ret void
+// CHECK: }
+
+void testIgnoredSmall() {
+  testReturnSmall();
+}
+
+// CHECK: define void @_Z14testParamLarge5Large(%[[STRUCT_LARGE:.*]]* %[[A:.*]])
+// CHECK: %[[CALL:.*]] = call %[[STRUCT_LARGE]]* @_ZN5LargeD1Ev(%[[STRUCT_LARGE]]* %[[A]])
+// CHECK: ret void
+// CHECK: }
+
+void testParamLarge(Large a) noexcept {
+}
+
+// CHECK: define void @_Z15testReturnLargev(%[[STRUCT_LARGE:.*]]* noalias sret %[[AGG_RESULT:.*]])
+// CHECK: %[[CALL:.*]] = call %[[STRUCT_LARGE]]* @_ZN5LargeC1Ev(%[[STRUCT_LARGE]]* %[[AGG_RESULT]])
+// CHECK: ret void
+// CHECK: }
+
+Large testReturnLarge() {
+  Large t;
+  return t;
+}
+
+// CHECK: define void @_Z14testCallLarge0v()
+// CHECK: %[[T:.*]] = alloca %[[STRUCT_LARGE:.*]], align 8
+// CHECK: %[[AGG_TMP:.*]] = alloca %[[STRUCT_LARGE]], align 8
+// CHECK: %[[CALL:.*]] = call %[[STRUCT_LARGE]]* @_ZN5LargeC1Ev(%[[STRUCT_LARGE]]* %[[T]])
+// CHECK: %[[CALL1:.*]] = call %[[STRUCT_LARGE]]* @_ZN5LargeC1ERKS_(%[[STRUCT_LARGE]]* %[[AGG_TMP]], %[[STRUCT_LARGE]]* dereferenceable(520) %[[T]])
+// CHECK: call void @_Z14testParamLarge5Large(%[[STRUCT_LARGE]]* %[[AGG_TMP]])
+// CHECK: %[[CALL2:.*]] = call %[[STRUCT_LARGE]]* @_ZN5LargeD1Ev(%[[STRUCT_LARGE]]* %[[T]])
+// CHECK: ret void
+// CHECK: }
+
+void testCallLarge0() {
+  Large t;
+  testParamLarge(t);
+}
+
+// CHECK: define void @_Z14testCallLarge1v()
+// CHECK: %[[AGG_TMP:.*]] = alloca %[[STRUCT_LARGE:.*]], align 8
+// CHECK: call void @_Z15testReturnLargev(%[[STRUCT_LARGE]]* sret %[[AGG_TMP]])
+// CHECK: call void @_Z14testParamLarge5Large(%[[STRUCT_LARGE]]* %[[AGG_TMP]])
+// CHECK: ret void
+// CHECK: }
+
+void testCallLarge1() {
+  testParamLarge(testReturnLarge());
+}
+
+// CHECK: define void @_Z16testIgnoredLargev()
+// CHECK: %[[AGG_TMP_ENSURED:.*]] = alloca %[[STRUCT_LARGE:.*]], align 8
+// CHECK: call void @_Z15testReturnLargev(%[[STRUCT_LARGE]]* sret %[[AGG_TMP_ENSURED]])
+// CHECK: %[[CALL:.*]] = call %[[STRUCT_LARGE]]* @_ZN5LargeD1Ev(%[[STRUCT_LARGE]]* %[[AGG_TMP_ENSURED]])
+// CHECK: ret void
+// CHECK: }
+
+void testIgnoredLarge() {
+  testReturnLarge();
+}
+
+// CHECK: define i64 @_Z20testReturnHasTrivialv()
+// CHECK: %[[RETVAL:.*]] = alloca %[[STRUCT_TRIVIAL:.*]], align 4
+// CHECK: %[[COERCE_DIVE:.*]] = getelementptr inbounds %[[STRUCT_TRIVIAL]], %[[STRUCT_TRIVIAL]]* %[[RETVAL]], i32 0, i32 0
+// CHECK: %[[V0:.*]] = load i32, i32* %[[COERCE_DIVE]], align 4
+// CHECK: %[[COERCE_VAL_II:.*]] = zext i32 %[[V0]] to i64
+// CHECK: ret i64 %[[COERCE_VAL_II]]
+// CHECK: }
+
+Trivial testReturnHasTrivial() {
+  Trivial t;
+  return t;
+}
+
+// CHECK: define void @_Z23testReturnHasNonTrivialv(%[[STRUCT_NONTRIVIAL:.*]]* noalias sret %[[AGG_RESULT:.*]])
+// CHECK: %[[CALL:.*]] = call %[[STRUCT_NONTRIVIAL]]* @_ZN10NonTrivialC1Ev(%[[STRUCT_NONTRIVIAL]]* %[[AGG_RESULT]])
+// CHECK: ret void
+// CHECK: }
+
+NonTrivial testReturnHasNonTrivial() {
+  NonTrivial t;
+  return t;
+}
+
+// CHECK: define void @_Z18testExceptionSmallv()
+// CHECK: %[[AGG_TMP:.*]] = alloca %[[STRUCT_SMALL]], align 8
+// CHECK: %[[AGG_TMP1:.*]] = alloca %[[STRUCT_SMALL]], align 8
+// CHECK: call %[[STRUCT_SMALL]]* @_ZN5SmallC1Ev(%[[STRUCT_SMALL]]* %[[AGG_TMP]])
+// CHECK: invoke %[[STRUCT_SMALL]]* @_ZN5SmallC1Ev(%[[STRUCT_SMALL]]* %[[AGG_TMP1]])
+
+// CHECK: call void @_Z20calleeExceptionSmall5SmallS_(i64 %{{.*}}, i64 %{{.*}})
+// CHECK-NEXT: ret void
+
+// CHECK: landingpad { i8*, i32 }
+// CHECK: call %[[STRUCT_SMALL]]* @_ZN5SmallD1Ev(%[[STRUCT_SMALL]]* %[[AGG_TMP]])
+// CHECK: br
+
+// CHECK: resume { i8*, i32 }
+
+void calleeExceptionSmall(Small, Small);
+
+void testExceptionSmall() {
+  calleeExceptionSmall(Small(), Small());
+}
+
+// CHECK: define void @_Z18testExceptionLargev()
+// CHECK: %[[AGG_TMP:.*]] = alloca %[[STRUCT_LARGE]], align 8
+// CHECK: %[[AGG_TMP1:.*]] = alloca %[[STRUCT_LARGE]], align 8
+// CHECK: call %[[STRUCT_LARGE]]* @_ZN5LargeC1Ev(%[[STRUCT_LARGE]]* %[[AGG_TMP]])
+// CHECK: invoke %[[STRUCT_LARGE]]* @_ZN5LargeC1Ev(%[[STRUCT_LARGE]]* %[[AGG_TMP1]])
+
+// CHECK: call void @_Z20calleeExceptionLarge5LargeS_(%[[STRUCT_LARGE]]* %[[AGG_TMP]], %[[STRUCT_LARGE]]* %[[AGG_TMP1]])
+// CHECK-NEXT: ret void
+
+// CHECK: landingpad { i8*, i32 }
+// CHECK: call %[[STRUCT_LARGE]]* @_ZN5LargeD1Ev(%[[STRUCT_LARGE]]* %[[AGG_TMP]])
+// CHECK: br
+
+// CHECK: resume { i8*, i32 }
+
+void calleeExceptionLarge(Large, Large);
+
+void testExceptionLarge() {
+  calleeExceptionLarge(Large(), Large());
+}
diff --git a/clang/test/CodeGenObjCXX/trivial_abi.mm b/clang/test/CodeGenObjCXX/trivial_abi.mm
new file mode 100644
index 00000000000..7d84338a4b0
--- /dev/null
+++ b/clang/test/CodeGenObjCXX/trivial_abi.mm
@@ -0,0 +1,104 @@
+// 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
+
+// CHECK: %[[STRUCT_STRONGWEAK:.*]] = type { i8*, i8* }
+// CHECK: %[[STRUCT_STRONG:.*]] = type { i8* }
+// CHECK: %[[STRUCT_S:.*]] = type { i8* }
+
+struct __attribute__((trivial_abi)) StrongWeak {
+  id fstrong;
+  __weak id fweak;
+};
+
+struct __attribute__((trivial_abi)) Strong {
+  id fstrong;
+};
+
+template<class T>
+struct __attribute__((trivial_abi)) S {
+  T a;
+};
+
+// CHECK: define void @_Z19testParamStrongWeak10StrongWeak(%[[STRUCT_STRONGWEAK]]* %{{.*}})
+// CHECK-NOT: call
+// CHECK: 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: 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: 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_RESULT]], %[[STRUCT_STRONGWEAK]]* dereferenceable(16) %[[V0]])
+// CHECK: ret void
+
+StrongWeak testReturnStrongWeak(StrongWeak *a) {
+  return *a;
+}
+
+// CHECK: define void @_Z15testParamStrong6Strong(i64 %[[A_COERCE:.*]])
+// CHECK: %[[A:.*]] = alloca %[[STRUCT_STRONG]], align 8
+// CHECK: %[[COERCE_DIVE:.*]] = getelementptr inbounds %[[STRUCT_STRONG]], %[[STRUCT_STRONG]]* %[[A]], i32 0, i32 0
+// CHECK: %[[COERCE_VAL_IP:.*]] = inttoptr i64 %[[A_COERCE]] to i8*
+// CHECK: store i8* %[[COERCE_VAL_IP]], i8** %[[COERCE_DIVE]], align 8
+// CHECK: %[[CALL:.*]] = call %[[STRUCT_STRONG]]* @_ZN6StrongD1Ev(%[[STRUCT_STRONG]]* %[[A]])
+// CHECK: ret void
+
+// CHECK: define linkonce_odr %[[STRUCT_STRONG]]* @_ZN6StrongD1Ev(
+
+void testParamStrong(Strong a) {
+}
+
+// CHECK: define void @_Z14testCallStrongP6Strong(%[[STRUCT_STRONG]]* %[[A:.*]])
+// CHECK: %[[A_ADDR:.*]] = alloca %[[STRUCT_STRONG]]*, align 8
+// CHECK: %[[AGG_TMP:.*]] = alloca %[[STRUCT_STRONG]], align 8
+// CHECK: store %[[STRUCT_STRONG]]* %[[A]], %[[STRUCT_STRONG]]** %[[A_ADDR]], align 8
+// CHECK: %[[V0:.*]] = load %[[STRUCT_STRONG]]*, %[[STRUCT_STRONG]]** %[[A_ADDR]], align 8
+// CHECK: %[[CALL:.*]] = call %[[STRUCT_STRONG]]* @_ZN6StrongC1ERKS_(%[[STRUCT_STRONG]]* %[[AGG_TMP]], %[[STRUCT_STRONG]]* dereferenceable(8) %[[V0]])
+// CHECK: %[[COERCE_DIVE:.*]] = getelementptr inbounds %[[STRUCT_STRONG]], %[[STRUCT_STRONG]]* %[[AGG_TMP]], i32 0, i32 0
+// CHECK: %[[V1:.*]] = load i8*, i8** %[[COERCE_DIVE]], align 8
+// CHECK: %[[COERCE_VAL_PI:.*]] = ptrtoint i8* %[[V1]] to i64
+// CHECK: call void @_Z15testParamStrong6Strong(i64 %[[COERCE_VAL_PI]])
+// CHECK: ret void
+
+void testCallStrong(Strong *a) {
+  testParamStrong(*a);
+}
+
+// CHECK: define i64 @_Z16testReturnStrongP6Strong(%[[STRUCT_STRONG]]* %[[A:.*]])
+// CHECK: entry:
+// CHECK: %[[RETVAL:.*]] = alloca %[[STRUCT_STRONG]], align 8
+// CHECK: %[[A_ADDR:.*]] = alloca %[[STRUCT_STRONG]]*, align 8
+// CHECK: store %[[STRUCT_STRONG]]* %[[A]], %[[STRUCT_STRONG]]** %[[A_ADDR]], align 8
+// CHECK: %[[V0:.*]] = load %[[STRUCT_STRONG]]*, %[[STRUCT_STRONG]]** %[[A_ADDR]], align 8
+// CHECK: %[[CALL:.*]] = call %[[STRUCT_STRONG]]* @_ZN6StrongC1ERKS_(%[[STRUCT_STRONG]]* %[[RETVAL]], %[[STRUCT_STRONG]]* dereferenceable(8) %[[V0]])
+// CHECK: %[[COERCE_DIVE:.*]] = getelementptr inbounds %[[STRUCT_STRONG]], %[[STRUCT_STRONG]]* %[[RETVAL]], i32 0, i32 0
+// CHECK: %[[V1:.*]] = load i8*, i8** %[[COERCE_DIVE]], 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-NOT: call
+// CHECK: ret void
+
+void testParamWeakTemplate(S<__weak id> a) {
+}
diff --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
index 1171a2d3709..1004459e9a1 100644
--- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -2,7 +2,7 @@
 
 // The number of supported attributes should never go down!
 
-// CHECK: #pragma clang attribute supports 66 attributes:
+// CHECK: #pragma clang attribute supports 67 attributes:
 // CHECK-NEXT: AMDGPUFlatWorkGroupSize (SubjectMatchRule_function)
 // CHECK-NEXT: AMDGPUNumSGPR (SubjectMatchRule_function)
 // CHECK-NEXT: AMDGPUNumVGPR (SubjectMatchRule_function)
@@ -66,6 +66,7 @@
 // CHECK-NEXT: TLSModel (SubjectMatchRule_variable_is_thread_local)
 // CHECK-NEXT: Target (SubjectMatchRule_function)
 // CHECK-NEXT: TestTypestate (SubjectMatchRule_function_is_member)
+// CHECK-NEXT: TrivialABI (SubjectMatchRule_record)
 // CHECK-NEXT: WarnUnusedResult (SubjectMatchRule_objc_method, SubjectMatchRule_enum, SubjectMatchRule_record, SubjectMatchRule_hasType_functionType)
 // CHECK-NEXT: XRayInstrument (SubjectMatchRule_function, SubjectMatchRule_objc_method)
 // CHECK-NEXT: XRayLogArgs (SubjectMatchRule_function, SubjectMatchRule_objc_method)
diff --git a/clang/test/SemaObjCXX/attr-trivial-abi.mm b/clang/test/SemaObjCXX/attr-trivial-abi.mm
new file mode 100644
index 00000000000..c83a94dcd98
--- /dev/null
+++ b/clang/test/SemaObjCXX/attr-trivial-abi.mm
@@ -0,0 +1,93 @@
+// RUN: %clang_cc1 -std=c++11 -fobjc-runtime-has-weak -fobjc-weak -fobjc-arc -fsyntax-only -verify %s
+
+void __attribute__((trivial_abi)) foo(); // expected-warning {{'trivial_abi' attribute only applies to classes}}
+
+struct [[clang::trivial_abi]] S0 {
+  int a;
+};
+
+struct __attribute__((trivial_abi)) S1 {
+  int a;
+};
+
+struct __attribute__((trivial_abi)) S2 { // expected-warning {{'trivial_abi' cannot be applied to 'S2'}}
+  __weak id a;
+};
+
+struct __attribute__((trivial_abi)) S3 { // expected-warning {{'trivial_abi' cannot be applied to 'S3'}}
+  virtual void m();
+};
+
+struct S4 {
+  int a;
+};
+
+struct __attribute__((trivial_abi)) S5 : public virtual S4 { // expected-warning {{'trivial_abi' cannot be applied to 'S5'}}
+};
+
+struct __attribute__((trivial_abi)) S9 : public S4 {
+};
+
+struct S6 {
+  __weak id a;
+};
+
+struct __attribute__((trivial_abi)) S12 { // expected-warning {{'trivial_abi' cannot be applied to 'S12'}}
+  __weak id a;
+};
+
+struct __attribute__((trivial_abi)) S13 { // expected-warning {{'trivial_abi' cannot be applied to 'S13'}}
+  __weak id a[2];
+};
+
+struct __attribute__((trivial_abi)) S7 { // expected-warning {{'trivial_abi' cannot be applied to 'S7'}}
+  S6 a;
+};
+
+struct __attribute__((trivial_abi)) S11 { // expected-warning {{'trivial_abi' cannot be applied to 'S11'}}
+  S6 a[2];
+};
+
+struct __attribute__((trivial_abi(1))) S8 { // expected-error {{'trivial_abi' attribute takes no arguments}}
+  int a;
+};
+
+// Do not warn when 'trivial_abi' is used to annotate a template class.
+template<class T>
+struct __attribute__((trivial_abi)) S10 {
+  T p;
+};
+
+S10<int *> p1;
+S10<__weak id> p2;
+
+template<>
+struct __attribute__((trivial_abi)) S10<id> { // expected-warning {{'trivial_abi' cannot be applied to 'S10<id>'}}
+  __weak id a;
+};
+
+template<class T>
+struct S14 {
+  T a;
+  __weak id b;
+};
+
+template<class T>
+struct __attribute__((trivial_abi)) S15 : S14<T> {
+};
+
+S15<int> s15;
+
+template<class T>
+struct __attribute__((trivial_abi)) S16 {
+  S14<T> a;
+};
+
+S16<int> s16;
+
+template<class T>
+struct __attribute__((trivial_abi)) S17 { // expected-warning {{'trivial_abi' cannot be applied to 'S17'}}
+  __weak id a;
+};
+
+S17<int> s17;