Remove unused 'receiver' field from generators

src/runtime/runtime-debug.cc

 // Copyright 2014 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/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/debug/debug-evaluate.h"
 #include "src/debug/debug-frames.h"
 #include "src/debug/debug-scopes.h"
@@ skipping 217 matching lines @@
         factory->NewStringFromAsciiChecked("[[GeneratorStatus]]");
     result->set(0, *generator_status);
     Handle<String> status_str = factory->NewStringFromAsciiChecked(status);
     result->set(1, *status_str);
 
     Handle<String> function =
         factory->NewStringFromAsciiChecked("[[GeneratorFunction]]");
     result->set(2, *function);
     result->set(3, generator->function());
 
-    Handle<String> receiver =
-        factory->NewStringFromAsciiChecked("[[GeneratorReceiver]]");
-    result->set(4, *receiver);
-    result->set(5, generator->receiver());
     return factory->NewJSArrayWithElements(result);
   } else if (Object::IsPromise(object)) {
     Handle<JSObject> promise = Handle<JSObject>::cast(object);
 
     Handle<Object> status_obj =
         DebugGetProperty(promise, isolate->factory()->promise_state_symbol());
     RUNTIME_ASSERT_HANDLIFIED(status_obj->IsSmi(), JSArray);
     const char* status = "rejected";
     int status_val = Handle<Smi>::cast(status_obj)->value();
     switch (status_val) {
@@ skipping 436 matching lines @@
   }
 
   // Add the value being returned.
   if (at_return) {
     details->set(details_index++, *return_value);
   }
 
   // Add the receiver (same as in function frame).
   Handle<Object> receiver(it.frame()->receiver(), isolate);
   DCHECK(!function->shared()->IsBuiltin());
-  DCHECK_IMPLIES(is_sloppy(shared->language_mode()), receiver->IsJSReceiver());
+  DCHECK_IMPLIES(
+      is_sloppy(shared->language_mode()),
+      receiver->IsJSReceiver() ||
+          // If this frame is a resumed generator, the receiver may be the hole,
+          // but
+          // it will not be observed as such due to forced context allocation.
+          (*receiver == isolate->heap()->the_hole_value() &&
+           function->shared()->is_generator()));
   details->set(kFrameDetailsReceiverIndex, *receiver);
 
   DCHECK_EQ(details_size, details_index);
   return *isolate->factory()->NewJSArrayWithElements(details);
 }
 
 
 RUNTIME_FUNCTION(Runtime_GetScopeCount) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
@@ skipping 836 matching lines @@
   return Smi::FromInt(isolate->debug()->is_active());
 }
 
 
 RUNTIME_FUNCTION(Runtime_DebugBreakInOptimizedCode) {
   UNIMPLEMENTED();
   return NULL;
 }
 }  // namespace internal
 }  // namespace v8