Fix some correctness issues with the store buffer shown up by...

src/store-buffer-inl.h

 // 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 34 matching lines @@
   Heap::public_set_store_buffer_top(top);
   if ((reinterpret_cast<uintptr_t>(top) & kStoreBufferOverflowBit) != 0) {
     ASSERT(top == limit_);
     Compact();
   } else {
     ASSERT(top < limit_);
   }
 }
 
 
+void StoreBuffer::set_store_buffer_mode(StoreBuffer::StoreBufferMode mode) {
+  if (FLAG_trace_gc) {
+    if (mode != store_buffer_mode_) {
+      if (mode == kStoreBufferDisabled) {
+        PrintF("Store buffer overflowed.\n");
+      } else if (mode == kStoreBufferBeingRebuilt) {
+        PrintF("Store buffer being rebuilt.\n");
+      } else if (mode == kStoreBufferFunctional) {
+        PrintF("Store buffer reenabled.\n");
+      }
+    }
+  }
+  store_buffer_mode_ = mode;
+}
+
+
 void StoreBuffer::EnterDirectlyIntoStoreBuffer(Address addr) {
   if (store_buffer_rebuilding_enabled_) {
     Address* top = old_top_;
     *top++ = addr;
     old_top_ = top;
     if (top >= old_limit_) {
       Counters::store_buffer_overflows.Increment();
-      store_buffer_mode_ = kStoreBufferDisabled;
+      set_store_buffer_mode(kStoreBufferDisabled);
       old_top_ = old_start_;
     }
+    old_buffer_is_sorted_ = false;
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_WRITE_BARRIER_INL_H_