Handle stepping requests after isolate interrupt event

runtime/vm/debugger.cc

Index: runtime/vm/debugger.cc
===================================================================
--- runtime/vm/debugger.cc	(revision 32907)
+++ runtime/vm/debugger.cc	(working copy)
@@ -187,20 +187,18 @@
 
 void Debugger::SignalIsolateEvent(EventType type) {
   if (event_handler_ != NULL) {
-    Debugger* debugger = Isolate::Current()->debugger();
-    ASSERT(debugger != NULL);
     DebuggerEvent event(type);
-    event.isolate_id = debugger->GetIsolateId();
+    event.isolate_id = isolate_id_;
     ASSERT(event.isolate_id != ILLEGAL_ISOLATE_ID);
     if (type == kIsolateInterrupted) {
-      DebuggerStackTrace* stack_trace = debugger->CollectStackTrace();
-      ASSERT(stack_trace->Length() > 0);
-      ASSERT(debugger->stack_trace_ == NULL);
-      debugger->stack_trace_ = stack_trace;
-      debugger->Pause(&event);
-      debugger->stack_trace_ = NULL;
-      // TODO(asiva): Need some work here to be able to single step after
-      // an interrupt.
+      DebuggerStackTrace* trace = CollectStackTrace();
+      ASSERT(trace->Length() > 0);
+      ASSERT(stack_trace_ == NULL);
+      stack_trace_ = trace;
+      resume_action_ = kContinue;
+      Pause(&event);
+      HandleSteppingRequest(trace);
+      stack_trace_ = NULL;
     } else {
       (*event_handler_)(&event);
     }
@@ -208,6 +206,15 @@
 }
 
 
+void Debugger::SignalIsolateInterrupted() {
+  if (event_handler_ != NULL) {
+    Debugger* debugger = Isolate::Current()->debugger();
+    ASSERT(debugger != NULL);
+    debugger->SignalIsolateEvent(kIsolateInterrupted);
+  }
+}
+
+
 const char* Debugger::QualifiedFunctionName(const Function& func) {
   const String& func_name = String::Handle(func.name());
   Class& func_class = Class::Handle(func.Owner());
@@ -1926,6 +1933,28 @@
 }
 
 
+void Debugger::HandleSteppingRequest(DebuggerStackTrace* stack_trace) {
+  stepping_fp_ = 0;
+  if (resume_action_ == kSingleStep) {
+    isolate_->set_single_step(true);
+  } else if (resume_action_ == kStepOver) {
+    isolate_->set_single_step(true);
+    ASSERT(stack_trace->Length() > 0);
+    stepping_fp_ = stack_trace->FrameAt(0)->fp();
+  } else if (resume_action_ == kStepOut) {
+    isolate_->set_single_step(true);
+    // Find topmost caller that is debuggable.
+    for (intptr_t i = 1; i < stack_trace->Length(); i++) {
+      ActivationFrame* frame = stack_trace->FrameAt(i);
+      if (frame->IsDebuggable()) {
+        stepping_fp_ = frame->fp();
+        break;
+      }
+    }
+  }
+}
+
+
 bool Debugger::IsDebuggable(const Function& func) {
   if (!IsDebuggableFunctionKind(func)) {
     return false;
@@ -1950,17 +1979,6 @@
 }
 
 
-static uword DebuggableCallerFP(DebuggerStackTrace* stack_trace) {
-  for (intptr_t i = 1; i < stack_trace->Length(); i++) {
-    ActivationFrame* frame = stack_trace->FrameAt(i);
-    if (frame->IsDebuggable()) {
-      return frame->fp();
-    }
-  }
-  return 0;
-}
-
-
 void Debugger::DebuggerStepCallback() {
   ASSERT(isolate_->single_step());
   // We can't get here unless the debugger event handler enabled
@@ -2008,17 +2026,7 @@
   ASSERT(stack_trace_ == NULL);
   stack_trace_ = CollectStackTrace();
   SignalPausedEvent(frame, NULL);
-
-  if (resume_action_ == kSingleStep) {
-    isolate_->set_single_step(true);
-    stepping_fp_ = 0;
-  } else if (resume_action_ == kStepOver) {
-    isolate_->set_single_step(true);
-    stepping_fp_ = frame->fp();
-  } else if (resume_action_ == kStepOut) {
-    isolate_->set_single_step(true);
-    stepping_fp_ = DebuggableCallerFP(stack_trace_);
-  }
+  HandleSteppingRequest(stack_trace_);
   stack_trace_ = NULL;
 }
 
@@ -2050,18 +2058,8 @@
   ASSERT(stack_trace_ == NULL);
   stack_trace_ = stack_trace;
   SignalPausedEvent(top_frame, bpt->src_bpt_);
+  HandleSteppingRequest(stack_trace_);
   stack_trace_ = NULL;
-
-  if (resume_action_ == kSingleStep) {
-    isolate_->set_single_step(true);
-    stepping_fp_ = 0;
-  } else if (resume_action_ == kStepOver) {
-    isolate_->set_single_step(true);
-    stepping_fp_ = top_frame->fp();
-  } else if (resume_action_ == kStepOut) {
-    isolate_->set_single_step(true);
-    stepping_fp_ = DebuggableCallerFP(stack_trace);
-  }
   if (bpt->IsInternal()) {
     RemoveInternalBreakpoints();
   }