[vm] Remove old async_debugger flag.

Effectively it is true for all environments where
debugger is actually present.

TEST=service tests

Change-Id: I0592e83004271ca32c107f4347f7bd82172b0a62
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/310622
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>

runtime/lib/async.cc

@@ -13,10 +13,10 @@ namespace dart {
 
 DEFINE_NATIVE_ENTRY(AsyncStarMoveNext_debuggerStepCheck, 0, 1) {
 #if !defined(PRODUCT)
-  GET_NON_NULL_NATIVE_ARGUMENT(Closure, async_op, arguments->NativeArgAt(0));
+  GET_NON_NULL_NATIVE_ARGUMENT(Closure, generator, arguments->NativeArgAt(0));
   Debugger* debugger = isolate->debugger();
-  if (debugger != nullptr) {
-    debugger->MaybeAsyncStepInto(async_op);
+  if (debugger != nullptr && debugger->IsSingleStepping()) {
+    debugger->AsyncStepInto(generator);
   }
 #endif
   return Object::null();

runtime/observatory/tests/service/pause_on_unhandled_async_exceptions2_test.dart

@@ -2,8 +2,8 @@
 // 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.
 //
-// VMOptions=--async_debugger
-// VMOptions=--async_debugger --optimization-counter-threshold=90
+// VMOptions=
+// VMOptions=--optimization-counter-threshold=90
 
 import 'package:observatory/service_io.dart';
 import 'package:observatory/models.dart' as M;
@@ -11,7 +11,14 @@ import 'package:test/test.dart';
 import 'test_helper.dart';
 import 'service_test_common.dart';
 
-const LINE_A = 35;
+// AUTOGENERATED START
+//
+// Update these constants by running:
+//
+//     dart runtime/observatory/tests/service/test_helper.dart update-lines
+//
+const int LINE_A = 42;
+// AUTOGENERATED END
 
 class Foo {}
 

runtime/observatory/tests/service/pause_on_unhandled_async_exceptions_test.dart

@@ -1,8 +1,6 @@
 // Copyright (c) 2017, 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.
-//
-// VMOptions=--async_debugger
 
 import 'package:observatory/service_io.dart';
 import 'package:observatory/models.dart' as M;
@@ -10,7 +8,14 @@ import 'package:test/test.dart';
 import 'test_helper.dart';
 import 'service_test_common.dart';
 
-const LINE_A = 36;
+// AUTOGENERATED START
+//
+// Update these constants by running:
+//
+//     dart runtime/observatory/tests/service/test_helper.dart update-lines
+//
+const int LINE_A = 41;
+// AUTOGENERATED END
 
 class Foo {}
 

runtime/observatory_2/tests/service_2/pause_on_unhandled_async_exceptions2_test.dart

@@ -2,8 +2,8 @@
 // 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.
 //
-// VMOptions=--async_debugger
-// VMOptions=--async_debugger --optimization-counter-threshold=90
+// VMOptions=
+// VMOptions=--optimization-counter-threshold=90
 
 import 'package:observatory_2/service_io.dart';
 import 'package:observatory_2/models.dart' as M;
@@ -11,7 +11,14 @@ import 'package:test/test.dart';
 import 'test_helper.dart';
 import 'service_test_common.dart';
 
-const LINE_A = 36;
+// AUTOGENERATED START
+//
+// Update these constants by running:
+//
+//     dart runtime/observatory/tests/service/test_helper.dart update-lines
+//
+const int LINE_A = 43;
+// AUTOGENERATED END
 
 class Foo {}
 

runtime/observatory_2/tests/service_2/pause_on_unhandled_async_exceptions_test.dart

@@ -1,15 +1,20 @@
 // Copyright (c) 2017, 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.
-//
-// VMOptions=--async_debugger
 
 import 'package:observatory_2/service_io.dart';
 import 'package:test/test.dart';
 import 'test_helper.dart';
 import 'service_test_common.dart';
 
-const LINE_A = 35;
+// AUTOGENERATED START
+//
+// Update these constants by running:
+//
+//     dart runtime/observatory/tests/service/test_helper.dart update-lines
+//
+const int LINE_A = 40;
+// AUTOGENERATED END
 
 class Foo {}
 

runtime/vm/debugger.cc

@@ -3098,26 +3098,25 @@ void Debugger::HandleSteppingRequest(DebuggerStackTrace* stack_trace,
       OS::PrintErr("HandleSteppingRequest- kStepOver %" Px "\n", stepping_fp_);
     }
   } else if (resume_action_ == kStepOut) {
-    if (FLAG_async_debugger) {
-      if (stack_trace->FrameAt(0)->function().IsAsyncFunction() ||
-          stack_trace->FrameAt(0)->function().IsAsyncGenerator()) {
-        CallerClosureFinder caller_closure_finder(Thread::Current()->zone());
-        // Request to step out of an async/async* closure.
-        const Object& async_op = Object::Handle(
-            stack_trace->FrameAt(0)->GetAsyncAwaiter(&caller_closure_finder));
-        if (!async_op.IsNull()) {
-          // Step out to the awaiter.
-          ASSERT(async_op.IsClosure());
-          AsyncStepInto(Closure::Cast(async_op));
-          if (FLAG_verbose_debug) {
-            OS::PrintErr("HandleSteppingRequest- kContinue to async_op %s\n",
-                         Function::Handle(Closure::Cast(async_op).function())
-                             .ToFullyQualifiedCString());
-          }
-          return;
+    if (stack_trace->FrameAt(0)->function().IsAsyncFunction() ||
+        stack_trace->FrameAt(0)->function().IsAsyncGenerator()) {
+      CallerClosureFinder caller_closure_finder(Thread::Current()->zone());
+      // Request to step out of an async/async* closure.
+      const Object& async_op = Object::Handle(
+          stack_trace->FrameAt(0)->GetAsyncAwaiter(&caller_closure_finder));
+      if (!async_op.IsNull()) {
+        // Step out to the awaiter.
+        ASSERT(async_op.IsClosure());
+        AsyncStepInto(Closure::Cast(async_op));
+        if (FLAG_verbose_debug) {
+          OS::PrintErr("HandleSteppingRequest- kContinue to async_op %s\n",
+                       Function::Handle(Closure::Cast(async_op).function())
+                           .ToFullyQualifiedCString());
         }
+        return;
       }
     }
+
     // Fall through to synchronous stepping.
     DeoptimizeWorld();
     NotifySingleStepping(true);
@@ -4124,14 +4123,6 @@ Breakpoint* Debugger::GetBreakpointByIdInTheList(intptr_t id,
   return nullptr;
 }
 
-void Debugger::MaybeAsyncStepInto(const Closure& async_op) {
-  if (FLAG_async_debugger && IsSingleStepping()) {
-    // We are single stepping, set a breakpoint on the closure activation
-    // and resume execution so we can hit the breakpoint.
-    AsyncStepInto(async_op);
-  }
-}
-
 void Debugger::AsyncStepInto(const Closure& awaiter) {
   Zone* zone = Thread::Current()->zone();
   CallerClosureFinder caller_closure_finder(zone);

runtime/vm/debugger.h

@@ -696,7 +696,6 @@ class Debugger {
   void RemoveBreakpoint(intptr_t bp_id);
   Breakpoint* GetBreakpointById(intptr_t id);
 
-  void MaybeAsyncStepInto(const Closure& async_op);
   void AsyncStepInto(const Closure& awaiter);
 
   void Continue();

runtime/vm/flag_list.h

@@ -92,8 +92,6 @@ constexpr bool FLAG_support_il_printer = false;
     "Abort if memory allocation fails - use only with --old-gen-heap-size")    \
   P(add_readonly_data_symbols, bool, false,                                    \
     "Add static symbols for objects in snapshot read-only data")               \
-  C(async_debugger, false, false, bool, true,                                  \
-    "Debugger support async functions.")                                       \
   P(background_compilation, bool, kDartUseBackgroundCompilation,               \
     "Run optimizing compilation in background")                                \
   P(check_token_positions, bool, false,                                        \

runtime/vm/object_store.cc

@@ -214,15 +214,6 @@ FunctionPtr ObjectStore::PrivateObjectLookup(const String& name) {
   return result.ptr();
 }
 
-#if !defined(DART_PRECOMPILED_RUNTIME)
-static void DisableDebuggingAndInlining(const Function& function) {
-  if (FLAG_async_debugger) {
-    function.set_is_debuggable(false);
-    function.set_is_inlinable(false);
-  }
-}
-#endif  // DART_PRECOMPILED_RUNTIME
-
 void ObjectStore::InitKnownObjects() {
   Thread* thread = Thread::Current();
   Zone* zone = thread->zone();
@@ -267,18 +258,19 @@ void ObjectStore::InitKnownObjects() {
   ASSERT(!field.IsNull());
   set_async_star_stream_controller_async_star_body(field);
 
-  if (FLAG_async_debugger) {
-    // Disable debugging and inlining of all functions on the
-    // _AsyncStarStreamController class.
-    const Array& functions = Array::Handle(zone, cls.current_functions());
-    for (intptr_t i = 0; i < functions.Length(); i++) {
-      function ^= functions.At(i);
-      if (function.IsNull()) {
-        break;
-      }
-      DisableDebuggingAndInlining(function);
+#if !defined(PRODUCT)
+  // Disable debugging and inlining of all functions on the
+  // _AsyncStarStreamController class.
+  const Array& functions = Array::Handle(zone, cls.current_functions());
+  for (intptr_t i = 0; i < functions.Length(); i++) {
+    function ^= functions.At(i);
+    if (function.IsNull()) {
+      break;
     }
+    function.set_is_debuggable(false);
+    function.set_is_inlinable(false);
   }
+#endif
 
   cls = async_lib.LookupClassAllowPrivate(Symbols::Stream());
   ASSERT(!cls.IsNull());