[cfe/ffi] Test _nativeEffect for @Natives

In a follow up, we will remove the transform from `@Native` to
`_asFunctionInternal`. However, we need to ensure that we keep
emitting `_nativeEffect` for struct return values classes if
`@Native`s are the only place instances are created.

The follow up CL will change the expect files.

TEST=pkg/vm/test/transformations/ffi_test

Bug: #47625
Change-Id: I1685683f48f1d16d6d10606f541f13e17d8583fe
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/332800
Reviewed-by: Alexander Markov <[email protected]>
Commit-Queue: Alexander Markov <[email protected]>
Commit-Queue: Daco Harkes <[email protected]>
Auto-Submit: Daco Harkes <[email protected]>

Author: dcharkes

pkg/vm/testcases/transformations/ffi/ffinative_compound_return.dart

@@ -0,0 +1,24 @@
+// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// The Struct1ByteInt code should not be shaken out if the only place instances
+// of this class are created is FFI call return values.
+
+import 'dart:ffi';
+
+void main() {
+  final result = returnStruct1ByteIntNative(-1);
+  print("result = $result");
+}
+
+// ignore: sdk_version_since
+@Native<Struct1ByteInt Function(Int8)>(symbol: 'ReturnStruct1ByteInt')
+external Struct1ByteInt returnStruct1ByteIntNative(int a0);
+
+final class Struct1ByteInt extends Struct {
+  @Int8()
+  external int a0;
+
+  String toString() => "(${a0})";
+}

pkg/vm/testcases/transformations/ffi/ffinative_compound_return.dart.aot.expect

@@ -0,0 +1,41 @@
+library #lib;
+import self as self;
+import "dart:core" as core;
+import "dart:ffi" as ffi;
+import "dart:_internal" as _in;
+import "dart:typed_data" as typ;
+
+import "dart:ffi";
+
+@#C6
+final class Struct1ByteInt extends ffi::Struct {
+  constructor #fromTypedDataBase([@vm.inferred-arg-type.metadata=dart.typed_data::_Uint8List] synthesized core::Object #typedDataBase) → self::Struct1ByteInt
+    : super ffi::Struct::_fromTypedDataBase(#typedDataBase)
+    ;
+[@vm.procedure-attributes.metadata=methodOrSetterCalledDynamically:false,getterCalledDynamically:false,hasThisUses:false,hasNonThisUses:false,hasTearOffUses:false,getterSelectorId:1] [@vm.unboxing-info.metadata=()->i]  get a0() → core::int
+    return [@vm.inferred-type.metadata=int] ffi::_loadInt8([@vm.direct-call.metadata=dart.ffi::_Compound._typedDataBase] [@vm.inferred-type.metadata=dart.typed_data::_Uint8List] this.{ffi::_Compound::_typedDataBase}{core::Object}, #C8.{core::List::[]}(ffi::_abi()){(core::int) → core::int*});
+[@vm.procedure-attributes.metadata=methodOrSetterCalledDynamically:false,getterCalledDynamically:false,hasThisUses:false,hasTearOffUses:false,methodOrSetterSelectorId:2,getterSelectorId:3]  method toString() → core::String
+    return "(${[@vm.direct-call.metadata=#lib::Struct1ByteInt.a0] this.{self::Struct1ByteInt::a0}{core::int}})";
+}
+[@vm.inferred-type.metadata=dart.core::_Closure]static final field (core::int) → self::Struct1ByteInt _returnStruct1ByteIntNative$Method$FfiNative$Ptr = block {
+  _in::_nativeEffect(new self::Struct1ByteInt::#fromTypedDataBase([@vm.inferred-type.metadata=dart.typed_data::_Uint8List] typ::Uint8List::•(#C9)));
+} =>[@vm.inferred-type.metadata=dart.core::_Closure] ffi::_asFunctionInternal<(core::int) → self::Struct1ByteInt, (ffi::Int8) → self::Struct1ByteInt>([@vm.inferred-type.metadata=dart.ffi::Pointer] ffi::_fromAddress<ffi::NativeFunction<(ffi::Int8) → self::Struct1ByteInt>*>(ffi::_ffi_resolver(#C10, #C11, #C9){(core::Object, core::Object, core::int) → core::int}), false)/*isLegacy*/;
+static method main() → void {
+  final self::Struct1ByteInt result = self::returnStruct1ByteIntNative([@vm.direct-call.metadata=dart.core::_IntegerImplementation.unary-] [@vm.inferred-type.metadata=int (skip check)] 1.{core::int::unary-}(){() → core::int});
+  core::print("result = ${result}");
+}
+[@vm.unboxing-info.metadata=(i)->b]static method returnStruct1ByteIntNative([@vm.inferred-arg-type.metadata=int] core::int a0) → self::Struct1ByteInt
+  return self::_returnStruct1ByteIntNative$Method$FfiNative$Ptr(a0){(core::int) → self::Struct1ByteInt};
+constants  {
+  #C1 = "vm:ffi:struct-fields"
+  #C2 = TypeLiteralConstant(ffi::Int8)
+  #C3 = <core::Type>[#C2]
+  #C4 = null
+  #C5 = ffi::_FfiStructLayout {fieldTypes:#C3, packing:#C4}
+  #C6 = core::pragma {name:#C1, options:#C5}
+  #C7 = 0
+  #C8 = <core::int*>[#C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7, #C7]
+  #C9 = 1
+  #C10 = "#lib"
+  #C11 = "ReturnStruct1ByteInt"
+}

pkg/vm/testcases/transformations/ffi/ffinative_compound_return.dart.expect

@@ -0,0 +1,55 @@
+library #lib;
+import self as self;
+import "dart:core" as core;
+import "dart:ffi" as ffi;
+import "dart:_internal" as _in;
+import "dart:typed_data" as typ;
+
+import "dart:ffi";
+
+@#C6
+final class Struct1ByteInt extends ffi::Struct {
+  synthetic constructor •() → self::Struct1ByteInt
+    : super ffi::Struct::•()
+    ;
+  constructor #fromTypedDataBase(synthesized core::Object #typedDataBase) → self::Struct1ByteInt
+    : super ffi::Struct::_fromTypedDataBase(#typedDataBase)
+    ;
+  @#C7
+  get a0() → core::int
+    return ffi::_loadInt8(this.{ffi::_Compound::_typedDataBase}{core::Object}, #C9.{core::List::[]}(ffi::_abi()){(core::int) → core::int*});
+  @#C7
+  set a0(core::int #externalFieldValue) → void
+    return ffi::_storeInt8(this.{ffi::_Compound::_typedDataBase}{core::Object}, #C9.{core::List::[]}(ffi::_abi()){(core::int) → core::int*}, #externalFieldValue);
+  method toString() → core::String
+    return "(${this.{self::Struct1ByteInt::a0}{core::int}})";
+  @#C11
+  static get #sizeOf() → core::int*
+    return #C13.{core::List::[]}(ffi::_abi()){(core::int) → core::int*};
+}
+static final field (core::int) → self::Struct1ByteInt _returnStruct1ByteIntNative$Method$FfiNative$Ptr = block {
+  _in::_nativeEffect(new self::Struct1ByteInt::#fromTypedDataBase(typ::Uint8List::•(#C12)));
+} =>ffi::_asFunctionInternal<(core::int) → self::Struct1ByteInt, (ffi::Int8) → self::Struct1ByteInt>(ffi::_fromAddress<ffi::NativeFunction<(ffi::Int8) → self::Struct1ByteInt>*>(ffi::_ffi_resolver(#C14, #C15, #C12){(core::Object, core::Object, core::int) → core::int}), false)/*isLegacy*/;
+static method main() → void {
+  final self::Struct1ByteInt result = self::returnStruct1ByteIntNative(1.{core::int::unary-}(){() → core::int});
+  core::print("result = ${result}");
+}
+static method returnStruct1ByteIntNative(core::int a0) → self::Struct1ByteInt
+  return self::_returnStruct1ByteIntNative$Method$FfiNative$Ptr(a0){(core::int) → self::Struct1ByteInt};
+constants  {
+  #C1 = "vm:ffi:struct-fields"
+  #C2 = TypeLiteralConstant(ffi::Int8)
+  #C3 = <core::Type>[#C2]
+  #C4 = null
+  #C5 = ffi::_FfiStructLayout {fieldTypes:#C3, packing:#C4}
+  #C6 = core::pragma {name:#C1, options:#C5}
+  #C7 = ffi::Int8 {}
+  #C8 = 0
+  #C9 = <core::int*>[#C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8, #C8]
+  #C10 = "vm:prefer-inline"
+  #C11 = core::pragma {name:#C10, options:#C4}
+  #C12 = 1
+  #C13 = <core::int*>[#C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12, #C12]
+  #C14 = "#lib"
+  #C15 = "ReturnStruct1ByteInt"
+}