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

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 553 matching lines @@
   RUNTIME_ASSERT(function->shared()->IsSubjectToDebugging());
   Handle<SharedFunctionInfo> shared(function->shared());
   Handle<ScopeInfo> scope_info(shared->scope_info());
   DCHECK(*scope_info != ScopeInfo::Empty(isolate));
 
   // Get the locals names and values into a temporary array.
   int local_count = scope_info->LocalCount();
   for (int slot = 0; slot < scope_info->LocalCount(); ++slot) {
     // Hide compiler-introduced temporary variables, whether on the stack or on
     // the context.
-    if (scope_info->LocalIsSynthetic(slot)) local_count--;
+    if (ScopeInfo::VariableIsSynthetic(scope_info->LocalName(slot))) {
+      local_count--;
+    }
   }
 
   Handle<FixedArray> locals =
       isolate->factory()->NewFixedArray(local_count * 2);
 
   // Fill in the values of the locals.
   int local = 0;
   int i = 0;
   for (; i < scope_info->StackLocalCount(); ++i) {
     // Use the value from the stack.
-    if (scope_info->LocalIsSynthetic(i)) continue;
+    if (ScopeInfo::VariableIsSynthetic(scope_info->LocalName(i))) continue;
     locals->set(local * 2, scope_info->LocalName(i));
     Handle<Object> value = frame_inspector.GetExpression(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->IsOptimizedOut()) value = isolate->factory()->undefined_value();
     locals->set(local * 2 + 1, *value);
     local++;
   }
   if (local < local_count) {
     // Get the context containing declarations.
     Handle<Context> context(
         Handle<Context>::cast(frame_inspector.GetContext())->closure_context());
     for (; i < scope_info->LocalCount(); ++i) {
-      if (scope_info->LocalIsSynthetic(i)) continue;
       Handle<String> name(scope_info->LocalName(i));
+      if (ScopeInfo::VariableIsSynthetic(*name)) continue;
       VariableMode mode;
       InitializationFlag init_flag;
       MaybeAssignedFlag maybe_assigned_flag;
       locals->set(local * 2, *name);
       int context_slot_index = ScopeInfo::ContextSlotIndex(
           scope_info, name, &mode, &init_flag, &maybe_assigned_flag);
       Object* value = context->get(context_slot_index);
       locals->set(local * 2 + 1, value);
       local++;
     }
@@ skipping 1032 matching lines @@
   return Smi::FromInt(isolate->debug()->is_active());
 }
 
 
 RUNTIME_FUNCTION(Runtime_DebugBreakInOptimizedCode) {
   UNIMPLEMENTED();
   return NULL;
 }
 }  // namespace internal
 }  // namespace v8