Refactor isolate interrupts to use OOB messages instead of interrupt bits.

runtime/vm/debugger.cc

 // Copyright (c) 2012, 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 "vm/debugger.h"
 
 #include "include/dart_api.h"
 
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 24 matching lines @@
             "Show invisible frames in debugger stack traces");
 DEFINE_FLAG(bool, trace_debugger_stacktrace, false,
             "Trace debugger stacktrace collection");
 DEFINE_FLAG(bool, verbose_debug, false, "Verbose debugger messages");
 DEFINE_FLAG(bool, steal_breakpoints, false,
             "Intercept breakpoints and other pause events before they "
             "are sent to the embedder and use a generic VM breakpoint "
             "handler instead.  This handler dispatches breakpoints to "
             "the VM service.");
 
+DECLARE_FLAG(bool, trace_isolates);
+
 
 Debugger::EventHandler* Debugger::event_handler_ = NULL;
 
 
 class RemoteObjectCache : public ZoneAllocated {
  public:
   explicit RemoteObjectCache(intptr_t initial_size);
   intptr_t AddObject(const Object& obj);
   RawObject* GetObj(intptr_t obj_id) const;
   bool IsValidId(intptr_t obj_id) const {
@@ skipping 257 matching lines @@
   }
 }
 
 
 void Debugger::SignalIsolateEvent(DebuggerEvent::EventType type) {
   if (HasEventHandler()) {
     DebuggerEvent event(isolate_, type);
     ASSERT(event.isolate_id() != ILLEGAL_ISOLATE_ID);
     if (type == DebuggerEvent::kIsolateInterrupted) {
       DebuggerStackTrace* trace = CollectStackTrace();
-      ASSERT(trace->Length() > 0);
-      event.set_top_frame(trace->FrameAt(0));
+      if (trace->Length() > 0) {
+        event.set_top_frame(trace->FrameAt(0));
+      }
       ASSERT(stack_trace_ == NULL);
       stack_trace_ = trace;
       resume_action_ = kContinue;
       Pause(&event);
       HandleSteppingRequest(trace);
       stack_trace_ = NULL;
     } else {
       InvokeEventHandler(&event);
     }
   }
 }
 
 
-void Debugger::SignalIsolateInterrupted() {
+RawError* Debugger::SignalIsolateInterrupted() {
   if (HasEventHandler()) {
-    Debugger* debugger = Isolate::Current()->debugger();
-    debugger->SignalIsolateEvent(DebuggerEvent::kIsolateInterrupted);
+    SignalIsolateEvent(DebuggerEvent::kIsolateInterrupted);
   }
+  Dart_IsolateInterruptCallback callback = isolate_->InterruptCallback();
+  if (callback) {
+    if (!(*callback)()) {
+      if (FLAG_trace_isolates) {
+        OS::Print("[!] Embedder api: terminating isolate:\n"
+                  "\tisolate:    %s\n", isolate_->name());
+      }
+      const String& msg = String::Handle(String::New("isolate terminated"));
+      return UnwindError::New(msg);
+    }
+  }
+
+  // If any error occurred while in the debug message loop, return it here.

[turnidge, 2015/09/15 22:14:10]

This could happen, for example, if the isolate receives a kill message while in
the debugger message loop.

+  const Error& error =
+      Error::Handle(isolate_, isolate_->object_store()->sticky_error());
+  isolate_->object_store()->clear_sticky_error();
+  return error.raw();
 }
 
 
 // The vm service handles breakpoint notifications in a different way
 // than the regular debugger breakpoint notifications.
 static void SendServiceBreakpointEvent(ServiceEvent::EventKind kind,
                                        Breakpoint* bpt) {
   if (Service::debug_stream.enabled()) {
     ServiceEvent service_event(Isolate::Current(), kind);
     service_event.set_breakpoint(bpt);
@@ skipping 2191 matching lines @@
     if ((iter.CurrentTokenKind() == Token::kIDENT) &&
         ((iter.CurrentLiteral() == Symbols::Await().raw()) ||
          (iter.CurrentLiteral() == Symbols::YieldKw().raw()))) {
       event.set_at_async_jump(true);
     }
   }
   Pause(&event);
 }
 
 
-void Debugger::DebuggerStepCallback() {
+RawError* Debugger::DebuggerStepCallback() {
   ASSERT(isolate_->single_step());
   // We can't get here unless the debugger event handler enabled
   // single stepping.
   ASSERT(HasEventHandler());
   // Don't pause recursively.
-  if (IsPaused()) return;
+  if (IsPaused()) {
+    return Error::null();
+  }
 
   // Check whether we are in a Dart function that the user is
   // interested in. If we saved the frame pointer of a stack frame
   // the user is interested in, we ignore the single step if we are
   // in a callee of that frame. Note that we assume that the stack
   // grows towards lower addresses.
   ActivationFrame* frame = TopDartFrame();
   ASSERT(frame != NULL);
 
   if (stepping_fp_ != 0) {
     // There is an "interesting frame" set. Only pause at appropriate
     // locations in this frame.
     if (stepping_fp_ > frame->fp()) {
       // We are in a callee of the frame we're interested in.
       // Ignore this stepping break.
-      return;
+      return Error::null();
     } else if (frame->fp() > stepping_fp_) {
       // We returned from the "interesting frame", there can be no more
       // stepping breaks for it. Pause at the next appropriate location
       // and let the user set the "interesting" frame again.
       stepping_fp_ = 0;
     }
   }
 
   if (!frame->IsDebuggable()) {
-    return;
+    return Error::null();
   }
   if (frame->TokenPos() == Scanner::kNoSourcePos) {
-    return;
+    return Error::null();
   }
 
   // Don't pause for a single step if there is a breakpoint set
   // at this location.
   if (HasActiveBreakpoint(frame->pc())) {
-    return;
+    return Error::null();
   }
 
   if (FLAG_verbose_debug) {
     OS::Print(">>> single step break at %s:%" Pd " (func %s token %" Pd ")\n",
               String::Handle(frame->SourceUrl()).ToCString(),
               frame->LineNumber(),
               String::Handle(frame->QualifiedFunctionName()).ToCString(),
               frame->TokenPos());
   }
 
   ASSERT(stack_trace_ == NULL);
   stack_trace_ = CollectStackTrace();
   SignalPausedEvent(frame, NULL);
   HandleSteppingRequest(stack_trace_);
   stack_trace_ = NULL;
+
+  // If any error occurred while in the debug message loop, return it here.
+  const Error& error =
+      Error::Handle(isolate_, isolate_->object_store()->sticky_error());
+  isolate_->object_store()->clear_sticky_error();
+  return error.raw();
 }
 
 
-void Debugger::SignalBpReached() {
+RawError* Debugger::SignalBpReached() {
   // We ignore this breakpoint when the VM is executing code invoked
   // by the debugger to evaluate variables values, or when we see a nested
   // breakpoint or exception event.
   if (ignore_breakpoints_ || IsPaused() || !HasEventHandler()) {
-    return;
+    return Error::null();
   }
   DebuggerStackTrace* stack_trace = CollectStackTrace();
   ASSERT(stack_trace->Length() > 0);
   ActivationFrame* top_frame = stack_trace->FrameAt(0);
   ASSERT(top_frame != NULL);
   CodeBreakpoint* cbpt = GetCodeBreakpoint(top_frame->pc());
   ASSERT(cbpt != NULL);
 
   BreakpointLocation* bpt_location = cbpt->bpt_location_;
   Breakpoint* bpt_hit = NULL;
@@ skipping 33 matching lines @@
         if (bpt->IsRepeated()) {
           bpt_hit = bpt;
           break;
         }
         bpt = bpt->next();
       }
     }
   }
 
   if (bpt_hit == NULL) {
-    return;
+    return Error::null();
   }
 
   if (FLAG_verbose_debug) {
     OS::Print(">>> hit %s breakpoint at %s:%" Pd " "
               "(token %" Pd ") (address %#" Px ")\n",
               cbpt->IsInternal() ? "internal" : "user",
               String::Handle(cbpt->SourceUrl()).ToCString(),
               cbpt->LineNumber(),
               cbpt->token_pos(),
               top_frame->pc());
   }
 
   ASSERT(stack_trace_ == NULL);
   stack_trace_ = stack_trace;
   SignalPausedEvent(top_frame, bpt_hit);
   HandleSteppingRequest(stack_trace_);
   stack_trace_ = NULL;
   if (cbpt->IsInternal()) {
     RemoveInternalBreakpoints();
   }
+
+  // If any error occurred while in the debug message loop, return it here.
+  const Error& error =
+      Error::Handle(isolate_, isolate_->object_store()->sticky_error());
+  isolate_->object_store()->clear_sticky_error();
+  return error.raw();
 }
 
 
 void Debugger::BreakHere(const String& msg) {
   // We ignore this breakpoint when the VM is executing code invoked
   // by the debugger to evaluate variables values, or when we see a nested
   // breakpoint or exception event.
   if (ignore_breakpoints_ || IsPaused() || !HasEventHandler()) {
     return;
   }
@@ skipping 469 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart