Fix new space shrinking to reset from-space.

src/spaces.cc

 // Copyright 2011 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 907 matching lines @@
 
 
 void NewSpace::Flip() {
   SemiSpace::Swap(&from_space_, &to_space_);
 }
 
 
 void NewSpace::Grow() {
   ASSERT(Capacity() < MaximumCapacity());
   if (to_space_.Grow()) {
-    // Only grow from space if we managed to grow to space.
+    // Only grow from space if we managed to grow to-space.
     if (!from_space_.Grow()) {
-      // If we managed to grow to space but couldn't grow from space,
-      // attempt to shrink to space.
+      // If we managed to grow to-space but couldn't grow from-space,
+      // attempt to shrink to-space.
       if (!to_space_.ShrinkTo(from_space_.Capacity())) {
         // We are in an inconsistent state because we could not
         // commit/uncommit memory from new space.
         V8::FatalProcessOutOfMemory("Failed to grow new space.");
       }
     }
   }
   ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
 }
 
 
 void NewSpace::Shrink() {
   int new_capacity = Max(InitialCapacity(), 2 * SizeAsInt());
   int rounded_new_capacity =
       RoundUp(new_capacity, static_cast<int>(OS::AllocateAlignment()));
   if (rounded_new_capacity < Capacity() &&
       to_space_.ShrinkTo(rounded_new_capacity))  {
-    // Only shrink from space if we managed to shrink to space.
+    // Only shrink from-space if we managed to shrink to-space.
+    from_space_.Reset();
     if (!from_space_.ShrinkTo(rounded_new_capacity)) {
-      // If we managed to shrink to space but couldn't shrink from
-      // space, attempt to grow to space again.
+      // If we managed to shrink to-space but couldn't shrink from
+      // space, attempt to grow to-space again.
       if (!to_space_.GrowTo(from_space_.Capacity())) {
         // We are in an inconsistent state because we could not
         // commit/uncommit memory from new space.
         V8::FatalProcessOutOfMemory("Failed to shrink new space.");
       }
     }
   }
   allocation_info_.limit = to_space_.page_high();
   ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
 }
@@ skipping 1537 matching lines @@
   for (HeapObject* obj = obj_it.Next(); obj != NULL; obj = obj_it.Next()) {
     if (obj->IsCode()) {
       Code* code = Code::cast(obj);
       isolate->code_kind_statistics()[code->kind()] += code->Size();
     }
   }
 }
 #endif  // DEBUG
 
 } }  // namespace v8::internal