Debugger support for step-into async and async* functions.

runtime/lib/stacktrace.cc

 // Copyright (c) 2013, 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.
 
 #include "lib/stacktrace.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/debugger.h"
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
 #include "vm/object_store.h"
@@ skipping 92 matching lines @@
   Thread* thread = Thread::Current();
   return CurrentStackTrace(thread, false, 0);
 }
 
 
 DEFINE_NATIVE_ENTRY(StackTrace_current, 0) {
   return CurrentStackTrace(thread, false);
 }
 
 
-DEFINE_NATIVE_ENTRY(StackTrace_asyncStackTraceHelper, 0) {
+DEFINE_NATIVE_ENTRY(StackTrace_asyncStackTraceHelper, 1) {
+  GET_NON_NULL_NATIVE_ARGUMENT(Closure, async_op, arguments->NativeArgAt(0));
+  if (FLAG_support_debugger) {
+    Debugger* debugger = isolate->debugger();
+    if (debugger != NULL) {
+      debugger->MaybeAsyncStepInto(async_op);
+    }
+  }
   return CurrentStackTrace(thread, true);
 }
 
 
 DEFINE_NATIVE_ENTRY(StackTrace_clearAsyncThreadStackTrace, 0) {
   thread->clear_async_stack_trace();
   return Object::null();
 }
 
 
@@ skipping 62 matching lines @@
 void _printCurrentStackTraceNoSafepoint() {
   StackFrameIterator frames(StackFrameIterator::kDontValidateFrames);
   StackFrame* frame = frames.NextFrame();
   while (frame != NULL) {
     OS::PrintErr("%s\n", frame->ToCString());
     frame = frames.NextFrame();
   }
 }
 
 }  // namespace dart