1 /*
   2  * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "gc/shared/barrierSet.hpp"
  27 #include "gc/shared/barrierSetAssembler.hpp"
  28 #include "runtime/thread.hpp"
  29 #include "utilities/macros.hpp"
  30 
  31 BarrierSet* BarrierSet::_barrier_set = NULL;
  32 
  33 class SetBarrierSetNonJavaThread : public ThreadClosure {
  34   BarrierSet* _barrier_set;
  35   size_t _count;
  36 
  37 public:
  38   SetBarrierSetNonJavaThread(BarrierSet* barrier_set) :
  39     _barrier_set(barrier_set), _count(0) {}
  40 
  41   virtual void do_thread(Thread* thread) {
  42     _barrier_set->on_thread_create(thread);
  43     ++_count;
  44   }
  45 
  46   size_t count() const { return _count; }
  47 };
  48 
  49 void BarrierSet::set_barrier_set(BarrierSet* barrier_set) {
  50   assert(_barrier_set == NULL, "Already initialized");
  51   _barrier_set = barrier_set;
  52 
  53   // Some threads are created before the barrier set, so the call to
  54   // BarrierSet::on_thread_create had to be deferred for them.  Now that
  55   // we have the barrier set, do those deferred calls.
  56 
  57   // First do any non-JavaThreads.
  58   SetBarrierSetNonJavaThread njt_closure(_barrier_set);
  59   Threads::non_java_threads_do(&njt_closure);
  60 
  61   // Do the current (main) thread.  Ensure it's the one and only
  62   // JavaThread so far.  Also verify that it isn't yet on the thread
  63   // list, else we'd also need to call BarrierSet::on_thread_attach.
  64   assert(Thread::current()->is_Java_thread(),
  65          "Expected main thread to be a JavaThread");
  66   assert((njt_closure.count() + 1) == Threads::threads_before_barrier_set(),
  67          "Unexpected JavaThreads before barrier set initialization: "
  68          "Non-JavaThreads: " SIZE_FORMAT ", all: " SIZE_FORMAT,
  69          njt_closure.count(), Threads::threads_before_barrier_set());
  70   assert(!JavaThread::current()->on_thread_list(),
  71          "Main thread already on thread list.");
  72   _barrier_set->on_thread_create(Thread::current());
  73 }
  74 
  75 // Called from init.cpp
  76 void gc_barrier_stubs_init() {
  77   BarrierSet* bs = BarrierSet::barrier_set();
  78 #ifndef ZERO
  79   BarrierSetAssembler* bs_assembler = bs->barrier_set_assembler();
  80   bs_assembler->barrier_stubs_init();
  81 #endif
  82 }