Disable concurrent marking/sweeping, and background compilation on ARMv5TE

runtime/vm/gc_marker.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/gc_marker.h"
 
 #include <map>
 #include <utility>
 #include <vector>
 
 #include "vm/allocation.h"
 #include "vm/dart_api_state.h"
 #include "vm/isolate.h"
 #include "vm/log.h"
 #include "vm/pages.h"
 #include "vm/raw_object.h"
 #include "vm/stack_frame.h"
 #include "vm/store_buffer.h"
 #include "vm/thread_barrier.h"
 #include "vm/thread_pool.h"
 #include "vm/thread_registry.h"
 #include "vm/timeline.h"
 #include "vm/visitor.h"
 #include "vm/object_id_ring.h"
 
 namespace dart {
 
-DEFINE_FLAG(int, marker_tasks, 2,
+// Disable concurrent marking by default on armv5te. The relevant
+// implementations are uniprocessors.
+#if defined(TARGET_ARCH_ARM_5TE)
+#define MARKER_TASKS 0
+#else
+#define MARKER_TASKS 2
+#endif
+
+DEFINE_FLAG(int, marker_tasks, MARKER_TASKS,

[Ivan Posva, 2016/05/12 17:19:46]

Can we please move these flags into the flag list?

[zra, 2016/05/12 19:54:21]

Done.

             "The number of tasks to spawn during old gen GC marking (0 means "
             "perform all marking on main thread).");
 DEFINE_FLAG(bool, log_marker_tasks, false,
             "Log debugging information for old gen GC marking tasks.");
 
 class DelaySet {
  private:
   typedef std::multimap<RawObject*, RawWeakProperty*> Map;
   typedef std::pair<RawObject*, RawWeakProperty*> MapEntry;
 
@@ skipping 712 matching lines @@
       barrier.Exit();
     }
     delay_set.ClearReferences();
     ProcessWeakTables(page_space);
     ProcessObjectIdTable(isolate);
   }
   Epilogue(isolate, invoke_api_callbacks);
 }
 
 }  // namespace dart