[debugger] do not expose temporary variables introduced by the parser.

src/debug/debug-frames.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/debug/debug-frames.h"
 
 #include "src/frames-inl.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 98 matching lines @@
 // frame.
 void FrameInspector::MaterializeStackLocals(Handle<JSObject> target,
                                             Handle<ScopeInfo> scope_info) {
   HandleScope scope(isolate_);
   // First fill all parameters.
   for (int i = 0; i < scope_info->ParameterCount(); ++i) {
     // Do not materialize the parameter if it is shadowed by a context local.
     // TODO(yangguo): check whether this is necessary, now that we materialize
     //                context locals as well.
     Handle<String> name(scope_info->ParameterName(i));
+    if (ScopeInfo::VariableIsSynthetic(*name)) continue;
     if (ParameterIsShadowedByContextLocal(scope_info, name)) continue;
 
     Handle<Object> value =
         i < GetParametersCount()
             ? GetParameter(i)
             : Handle<Object>::cast(isolate_->factory()->undefined_value());
     DCHECK(!value->IsTheHole());
 
     JSObject::SetOwnPropertyIgnoreAttributes(target, name, value, NONE).Check();
   }
 
   // Second fill all stack locals.
   for (int i = 0; i < scope_info->StackLocalCount(); ++i) {
-    if (scope_info->LocalIsSynthetic(i)) continue;
     Handle<String> name(scope_info->StackLocalName(i));
+    if (ScopeInfo::VariableIsSynthetic(*name)) continue;
     Handle<Object> value = GetExpression(scope_info->StackLocalIndex(i));
     // TODO(yangguo): We convert optimized out values to {undefined} when they
     // are passed to the debugger. Eventually we should handle them somehow.
     if (value->IsTheHole()) value = isolate_->factory()->undefined_value();
     if (value->IsOptimizedOut()) value = isolate_->factory()->undefined_value();
     JSObject::SetOwnPropertyIgnoreAttributes(target, name, value, NONE).Check();
   }
 }
 
 
@@ skipping 11 matching lines @@
     // Optimized frames are not supported. Simply give up.
     return;
   }
 
   HandleScope scope(isolate_);
 
   // Parameters.
   for (int i = 0; i < scope_info->ParameterCount(); ++i) {
     // Shadowed parameters were not materialized.
     Handle<String> name(scope_info->ParameterName(i));
+    if (ScopeInfo::VariableIsSynthetic(*name)) continue;
     if (ParameterIsShadowedByContextLocal(scope_info, name)) continue;
 
     DCHECK(!frame_->GetParameter(i)->IsTheHole());
     Handle<Object> value =
         Object::GetPropertyOrElement(target, name).ToHandleChecked();
     frame_->SetParameterValue(i, *value);
   }
 
   // Stack locals.
   for (int i = 0; i < scope_info->StackLocalCount(); ++i) {
-    if (scope_info->LocalIsSynthetic(i)) continue;
+    Handle<String> name(scope_info->StackLocalName(i));
+    if (ScopeInfo::VariableIsSynthetic(*name)) continue;
     int index = scope_info->StackLocalIndex(i);
     if (frame_->GetExpression(index)->IsTheHole()) continue;
     Handle<Object> value =
-        Object::GetPropertyOrElement(
-            target, handle(scope_info->StackLocalName(i), isolate_))
-            .ToHandleChecked();
+        Object::GetPropertyOrElement(target, name).ToHandleChecked();
     frame_->SetExpression(index, *value);
   }
 }
 
 
 bool FrameInspector::ParameterIsShadowedByContextLocal(
     Handle<ScopeInfo> info, Handle<String> parameter_name) {
   VariableMode mode;
   InitializationFlag init_flag;
   MaybeAssignedFlag maybe_assigned_flag;
@@ skipping 24 matching lines @@
       if (!frames[i].function()->shared()->IsSubjectToDebugging()) continue;
       if (++count == index) return i;
     }
   }
   return -1;
 }
 
 
 }  // namespace internal
 }  // namespace v8