[vm/compiler] Fix handling of captured try_finally_return_value variable
In async/async* methods synthetic :try_finally_return_value variable
(which is used to hold return value across finally) could be
captured, so flow graph builder needs to have correct context_depth_
in order to access it using LoadLocal(finally_return_variable)
when building flow graph for return statement.
Previously, flow graph builder left context in an unspecified state
and depth after TranslateFinallyFinalizers(NULL, -1), which caused
incorrect code being generated for LoadLocal(finally_return_variable).
This change fixes this problem by
* passing correct target_context_depth to TranslateFinallyFinalizers
so context is adjusted to a known depth regardless of context
depth which is used by finally;
* setting context_depth_ for LoadLocal(finally_return_variable)
and then restoring it (to be able to continue building flow graph
for the enclosing AST nodes).
TEST=tests/language/async_star/regression_47610_test.dart
Fixes https://github.com/dart-lang/sdk/issues/47610
Change-Id: Id15ea719ddda892eaff0b06f6450b1a8de36e8da
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/219283
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
diff --git a/runtime/vm/compiler/frontend/kernel_binary_flowgraph.cc b/runtime/vm/compiler/frontend/kernel_binary_flowgraph.cc
index 798174d..6bf2d87 100644
--- a/runtime/vm/compiler/frontend/kernel_binary_flowgraph.cc
+++ b/runtime/vm/compiler/frontend/kernel_binary_flowgraph.cc
@@ -4869,17 +4869,28 @@
if (instructions.is_open()) {
if (inside_try_finally) {
- ASSERT(scopes()->finally_return_variable != NULL);
+ LocalVariable* const finally_return_variable =
+ scopes()->finally_return_variable;
+ ASSERT(finally_return_variable != nullptr);
const Function& function = parsed_function()->function();
if (NeedsDebugStepCheck(function, position)) {
instructions += DebugStepCheck(position);
}
- instructions += StoreLocal(position, scopes()->finally_return_variable);
+ instructions += StoreLocal(position, finally_return_variable);
instructions += Drop();
- instructions += TranslateFinallyFinalizers(NULL, -1);
+ const intptr_t target_context_depth =
+ finally_return_variable->is_captured()
+ ? finally_return_variable->owner()->context_level()
+ : -1;
+ instructions += TranslateFinallyFinalizers(nullptr, target_context_depth);
if (instructions.is_open()) {
- instructions += LoadLocal(scopes()->finally_return_variable);
+ const intptr_t saved_context_depth = B->context_depth_;
+ if (finally_return_variable->is_captured()) {
+ B->context_depth_ = target_context_depth;
+ }
+ instructions += LoadLocal(finally_return_variable);
instructions += Return(TokenPosition::kNoSource);
+ B->context_depth_ = saved_context_depth;
}
} else {
instructions += Return(position);
diff --git a/tests/language/async_star/regression_47610_test.dart b/tests/language/async_star/regression_47610_test.dart
new file mode 100644
index 0000000..9bb4ce2
--- /dev/null
+++ b/tests/language/async_star/regression_47610_test.dart
@@ -0,0 +1,32 @@
+// Copyright (c) 2021, 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.
+
+// Regression test for https://github.com/dart-lang/sdk/issues/47610.
+// Tests returning value from a deep context depth along with
+// breaking from 'await for'.
+
+import "dart:async";
+import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
+
+Stream<int> foo() async* {
+ for (int i = 0; i < 2; ++i) {
+ for (int j = 0; j < 2; ++j) {
+ for (int k = 0; k < 2; ++k) {
+ yield i + j + k;
+ }
+ }
+ }
+}
+
+void test() async {
+ await for (var x in foo()) {
+ Expect.equals(0, x);
+ break;
+ }
+}
+
+void main() {
+ asyncTest(test);
+}
diff --git a/tests/language_2/async_star/regression_47610_test.dart b/tests/language_2/async_star/regression_47610_test.dart
new file mode 100644
index 0000000..4fd7815
--- /dev/null
+++ b/tests/language_2/async_star/regression_47610_test.dart
@@ -0,0 +1,34 @@
+// Copyright (c) 2021, 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.
+
+// @dart = 2.9
+
+// Regression test for https://github.com/dart-lang/sdk/issues/47610.
+// Tests returning value from a deep context depth along with
+// breaking from 'await for'.
+
+import "dart:async";
+import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
+
+Stream<int> foo() async* {
+ for (int i = 0; i < 2; ++i) {
+ for (int j = 0; j < 2; ++j) {
+ for (int k = 0; k < 2; ++k) {
+ yield i + j + k;
+ }
+ }
+ }
+}
+
+void test() async {
+ await for (var x in foo()) {
+ Expect.equals(0, x);
+ break;
+ }
+}
+
+void main() {
+ asyncTest(test);
+}
