/*

 * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

package sun.jvm.hotspot.runtime;

import java.util.*;

import sun.jvm.hotspot.debugger.*;

import sun.jvm.hotspot.types.*;

/** Very minimal port for now to get frames working */

public class StubRoutines {

  private static AddressField      callStubReturnAddressField;

  private static AddressField      callStubCompiledReturnAddressField;

  static {

    VM.registerVMInitializedObserver(new Observer() {

        public void update(Observable o, Object data) {

          initialize(VM.getVM().getTypeDataBase());

        }

      });

  }

  private static synchronized void initialize(TypeDataBase db) {

    Type type = db.lookupType("StubRoutines");

    callStubReturnAddressField = type.getAddressField("_call_stub_return_address");

    // Only some platforms have specific return from compiled to call_stub

    try {

      type = db.lookupType("StubRoutines::x86");

      if (type != null) {

        callStubCompiledReturnAddressField = type.getAddressField("_call_stub_compiled_return");

      }

    } catch (RuntimeException re) {

      callStubCompiledReturnAddressField = null;

    }

    if (callStubCompiledReturnAddressField == null && VM.getVM().getCPU().equals("x86")) {

      throw new InternalError("Missing definition for _call_stub_compiled_return");

    }

  }

  public StubRoutines() {

  }

  public boolean returnsToCallStub(Address returnPC) {

    Address addr = callStubReturnAddressField.getValue();

    boolean result = false;

    if (addr == null) {

      result = (addr == returnPC);

    } else {

      result = addr.equals(returnPC);

    }

    if (result || callStubCompiledReturnAddressField == null ) return result;

    // Could be a return to compiled code return point

    addr = callStubCompiledReturnAddressField.getValue();

    if (addr == null) {

      return (addr == returnPC);

    } else {

      return (addr.equals(returnPC));

    }

  }

}