Remove prototype checks for leaf maps in optimized code.

src/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2351 matching lines @@
   bool parent_is_alive = Marking::MarkBitFrom(parent).Get();
   if (!current_is_alive && parent_is_alive) {
     parent->ClearNonLiveTransitions(heap());
   }
 }
 
 
 void MarkCompactCollector::ClearAndDeoptimizeDependentCodes(Map* map) {
   AssertNoAllocation no_allocation_scope;
   DependentCodes* codes = map->dependent_codes();
-  DependentCodes::GroupStartIndexes starts;
-  codes->ComputeGroupStartIndexes(starts);
-  int number_of_codes = starts[DependentCodes::kGroupCount];
+  DependentCodes::GroupStartIndexes starts(codes);
+  int number_of_codes = starts.at(DependentCodes::kGroupCount);
   if (number_of_codes == 0) return;
   for (int i = 0; i < number_of_codes; i++) {
     Code* code = codes->code_at(i);
     if (IsMarked(code) && !code->marked_for_deoptimization()) {
       code->set_marked_for_deoptimization(true);
     }
     codes->clear_code_at(i);
   }
   map->set_dependent_codes(DependentCodes::cast(heap()->empty_fixed_array()));
 }
 
 
 void MarkCompactCollector::ClearNonLiveDependentCodes(Map* map) {
   AssertNoAllocation no_allocation_scope;
   DependentCodes* codes = map->dependent_codes();
-  DependentCodes::GroupStartIndexes starts;
-  codes->ComputeGroupStartIndexes(starts);
-  int number_of_codes = starts[DependentCodes::kGroupCount];
+  DependentCodes::GroupStartIndexes starts(codes);
+  int number_of_codes = starts.at(DependentCodes::kGroupCount);
   if (number_of_codes == 0) return;
   int new_number_of_codes = 0;
   // Go through all groups, remove dead codes and compact.
   for (int g = 0; g < DependentCodes::kGroupCount; g++) {
     int group_number_of_codes = 0;
-    for (int i = starts[g]; i < starts[g + 1]; i++) {
+    for (int i = starts.at(g); i < starts.at(g + 1); i++) {
       Code* code = codes->code_at(i);
       if (IsMarked(code) && !code->marked_for_deoptimization()) {
         if (new_number_of_codes + group_number_of_codes != i) {
           codes->set_code_at(new_number_of_codes + group_number_of_codes, code);
         }
         Object** slot = codes->code_slot_at(new_number_of_codes +
                                             group_number_of_codes);
         RecordSlot(slot, slot, code);
         group_number_of_codes++;
       }
@@ skipping 1674 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal