8210498: nmethod entry barriers

Reviewed-by: kvn, pliden

src/hotspot/share/gc/shared/barrierSetNMethod.hpp

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_CODE_NMETHOD_BARRIER_HPP
+#define SHARE_CODE_NMETHOD_BARRIER_HPP
+
+#include "memory/allocation.hpp"
+#include "utilities/globalDefinitions.hpp"
+#include "utilities/sizes.hpp"
+
+class nmethod;
+
+class BarrierSetNMethod: public CHeapObj<mtGC> {
+  bool supports_entry_barrier(nmethod* nm);
+  void deoptimize(nmethod* nm, address* return_addr_ptr);
+
+protected:
+  virtual int disarmed_value() const;
+  virtual bool nmethod_entry_barrier(nmethod* nm) = 0;
+
+public:
+  virtual ByteSize thread_disarmed_offset() const = 0;
+
+  static int nmethod_stub_entry_barrier(address* return_address_ptr);
+  bool nmethod_osr_entry_barrier(nmethod* nm);
+  bool is_armed(nmethod* nm);
+  void disarm(nmethod* nm);
+};
+
+
+#endif // SHARE_CODE_NMETHOD_BARRIER_HPP