[futex] Allow debugger to break in the middle of a futexWait

src/futex-emulation.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/futex-emulation.h"
 
 #include <limits>
 
 #include "src/base/macros.h"
 #include "src/base/platform/time.h"
 #include "src/conversions.h"
+#include "src/debug/debug.h"
 #include "src/handles-inl.h"
 #include "src/isolate.h"
 #include "src/list-inl.h"
 
 namespace v8 {
 namespace internal {
 
 base::LazyMutex FutexEmulation::mutex_ = LAZY_MUTEX_INITIALIZER;
 base::LazyInstance<FutexWaitList>::type FutexEmulation::wait_list_ =
     LAZY_INSTANCE_INITIALIZER;
@@ skipping 112 matching lines @@
     //    interrupted_ will be set to 1. This will be checked below.
     // 2) After interrupted has been checked here, but before mutex_ is
     //    acquired: interrupted is checked again below, with mutex_ locked.
     //    Because the wakeup signal also acquires mutex_, we know it will not
     //    be able to notify until mutex_ is released below, when waiting on the
     //    condition variable.
     // 3) After the mutex is released in the call to WaitFor(): this
     // notification will wake up the condition variable. node->waiting() will
     // be false, so we'll loop and then check interrupts.
     if (interrupted) {
+      EnableBreakInNonDebuggable enabler(isolate->debug(), true);
+
       Object* interrupt_object = isolate->stack_guard()->HandleInterrupts();
       if (interrupt_object->IsException()) {
         result = interrupt_object;
         mutex_.Pointer()->Lock();
         break;
       }
     }
 
     mutex_.Pointer()->Lock();
 
@@ skipping 113 matching lines @@
     }
 
     node = node->next_;
   }
 
   return Smi::FromInt(waiters);
 }
 
 }  // namespace internal
 }  // namespace v8