Trigger exception debug event for promises at the throw site.

src/debug.h

 // Copyright 2012 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.
 
 #ifndef V8_DEBUG_H_
 #define V8_DEBUG_H_
 
 #include "allocation.h"
 #include "arguments.h"
 #include "assembler.h"
@@ skipping 217 matching lines @@
                               Handle<Object> break_point_object,
                               int* source_position,
                               BreakPositionAlignment alignment);
   void ClearBreakPoint(Handle<Object> break_point_object);
   void ClearAllBreakPoints();
   void FloodWithOneShot(Handle<JSFunction> function);
   void FloodBoundFunctionWithOneShot(Handle<JSFunction> function);
   void FloodHandlerWithOneShot();
   void ChangeBreakOnException(ExceptionBreakType type, bool enable);
   bool IsBreakOnException(ExceptionBreakType type);
+
+  void PromiseHandlePrologue(Handle<JSFunction> promise);

[rossberg, 2014/04/30 12:55:17]

Perhaps name the argument get_promise for clarity.

[Yang, 2014/04/30 13:20:14]

Done.

+  void PromiseHandleEpilogue();
+  // Returns a promise if it does not have a reject handler.
+  Handle<Object> GetPromiseForUncaughtException();
+
   void PrepareStep(StepAction step_action,
                    int step_count,
                    StackFrame::Id frame_id);
   void ClearStepping();
   void ClearStepOut();
   bool IsStepping() { return thread_local_.step_count_ > 0; }
   bool StepNextContinue(BreakLocationIterator* break_location_iterator,
                         JavaScriptFrame* frame);
   static Handle<DebugInfo> GetDebugInfo(Handle<SharedFunctionInfo> shared);
   static bool HasDebugInfo(Handle<SharedFunctionInfo> shared);
@@ skipping 286 matching lines @@
   // Cache of all scripts in the heap.
   ScriptCache* script_cache_;
 
   // List of active debug info objects.
   DebugInfoListNode* debug_info_list_;
 
   bool disable_break_;
   bool break_on_exception_;
   bool break_on_uncaught_exception_;
 
+  // When a promise is being resolved, we may want to trigger a debug event for
+  // the case we catch a throw.  For this purpose we remember the try-catch
+  // handler address that would catch the exception.  We also hold onto a
+  // closure that returns a promise if the exception is considered uncaught.
+  StackHandler* current_promise_catch_handler_;
+  MaybeHandle<JSFunction> current_promise_getter_;
+
   // Per-thread data.
   class ThreadLocal {
    public:
     // Counter for generating next break id.
     int break_count_;
 
     // Current break id.
     int break_id_;
 
     // Frame id for the frame of the current break.
@@ skipping 216 matching lines @@
       Handle<Object> break_points_hit);
   MUST_USE_RESULT MaybeHandle<Object> MakeExceptionEvent(
       Handle<Object> exception,
       bool uncaught,
       Handle<Object> promise);
   MUST_USE_RESULT MaybeHandle<Object> MakeCompileEvent(
       Handle<Script> script, bool before);
   MUST_USE_RESULT MaybeHandle<Object> MakeScriptCollectedEvent(int id);
 
   void OnDebugBreak(Handle<Object> break_points_hit, bool auto_continue);
-  void OnException(Handle<Object> exception,
-                   bool uncaught,
-                   Handle<Object> promise = Handle<Object>::null());
+  void OnException(Handle<Object> exception, bool uncaught);
   void OnBeforeCompile(Handle<Script> script);
 
   enum AfterCompileFlags {
     NO_AFTER_COMPILE_FLAGS,
     SEND_WHEN_DEBUGGING
   };
   void OnAfterCompile(Handle<Script> script,
                       AfterCompileFlags after_compile_flags);
   void OnScriptCollected(int id);
   void ProcessDebugEvent(v8::DebugEvent event,
@@ skipping 243 matching lines @@
   Mutex mutex_;
   bool already_signalled_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageDispatchHelperThread);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_DEBUG_H_