- Add and enable concurrent sweeper.

runtime/vm/scavenger.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/scavenger.h"
 
 #include <algorithm>
 #include <map>
 #include <utility>
 
@@ skipping 34 matching lines @@
   return bits == kForwarded;
 }
 
 
 static inline uword ForwardedAddr(uword header) {
   ASSERT(IsForwarding(header));
   return header & ~kForwardingMask;
 }
 
 
-static inline void ForwardTo(uword orignal, uword target) {
+static inline void ForwardTo(uword original, uword target) {
   // Make sure forwarding can be encoded.
   ASSERT((target & kForwardingMask) == 0);
-  *reinterpret_cast<uword*>(orignal) = target | kForwarded;
+  *reinterpret_cast<uword*>(original) = target | kForwarded;
 }
 
 
 class BoolScope : public ValueObject {
  public:
   BoolScope(bool* addr, bool value) : _addr(addr), _value(*addr) {
     *_addr = value;
   }
   ~BoolScope() {
     *_addr = _value;
@@ skipping 406 matching lines @@
   if (avg_frac < (FLAG_early_tenuring_threshold / 100.0)) {
     // Remember the limit to which objects have been copied.
     survivor_end_ = top_;
   } else {
     // Move survivor end to the end of the to_ space, making all surviving
     // objects candidates for promotion next time.
     survivor_end_ = end_;
   }
 
 #if defined(DEBUG)
-  VerifyStoreBufferPointerVisitor verify_store_buffer_visitor(isolate, to_);
-  heap_->IterateOldPointers(&verify_store_buffer_visitor);
+  // We can only safely verify the store buffers from old space if there is no
+  // concurrent old space task. At the same time we prevent new tasks from
+  // being spawned.
+  {
+    PageSpace* page_space = heap_->old_space();
+    MonitorLocker ml(page_space->tasks_lock());
+    if (page_space->tasks() == 0) {
+      VerifyStoreBufferPointerVisitor verify_store_buffer_visitor(isolate, to_);
+      heap_->IterateOldPointers(&verify_store_buffer_visitor);
+    }
+  }
 #endif  // defined(DEBUG)
   from_->Delete();
   from_ = NULL;
   if (invoke_api_callbacks && (isolate->gc_epilogue_callback() != NULL)) {
     (isolate->gc_epilogue_callback())();
   }
 }
 
 
 void Scavenger::IterateStoreBuffers(Isolate* isolate,
@@ skipping 376 matching lines @@
 }
 
 
 void Scavenger::FreeExternal(intptr_t size) {
   ASSERT(size >= 0);
   external_size_ -= size;
   ASSERT(external_size_ >= 0);
 }
 
 }  // namespace dart