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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * accompanied this code).

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 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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/**

 * @test

 * @bug 6880034

 * @summary SIGBUS during deoptimisation at a safepoint on 64bit-SPARC

 *

 * @run main/othervm -Xcomp -Xbatch

 *    -XX:+PrintCompilation

 *    -XX:CompileCommand=compileonly,compiler.c2.Test6880034::deopt_compiledframe_at_safepoint

 *    compiler.c2.Test6880034

 */

package compiler.c2;

// This test provokes a deoptimisation at a safepoint.

//

// It achieves this by compiling the method 'deopt_compiledframe_at_safepoint'

// before its first usage at a point in time when a call to the virtual method

// A::doSomething() from within 'deopt_compiledframe_at_safepoint' can be

// optimised to a static call because class A has no descendants.

//

// Later, when deopt_compiledframe_at_safepoint() is running, class B which

// extends A and overrides the virtual method "doSomething()", is loaded

// asynchronously in another thread.  This makes the compiled code of

// 'deopt_compiledframe_at_safepoint' invalid and triggers a deoptimisation of

// the frame where 'deopt_compiledframe_at_safepoint' is running in a

// loop.

//

// The deoptimisation leads to a SIGBUS on 64-bit server VMs on SPARC and to

// an incorrect result on 32-bit server VMs on SPARC due to a regression

// introduced by the change: "6420645: Create a vm that uses compressed oops

// for up to 32gb heapsizes"

// (http://hg.openjdk.java.net/jdk7/jdk7/hotspot/rev/ba764ed4b6f2).  Further

// investigation showed that change 6420645 is not really the root cause of

// this error but only reveals a problem with the float register encodings in

// sparc.ad which was hidden until now.

//

// Notice that for this test to fail in jtreg it is crucial that

// deopt_compiledframe_at_safepoint() runs in the main thread. Otherwise a

// crash in deopt_compiledframe_at_safepoint() will not be detected as a test

// failure by jtreg.

//

// Author: Volker H. Simonis

public class Test6880034 {

  static class A {

    public int doSomething() {

      return 0;

    }

  }

  static class B extends A {

    public B() {}

    // override 'A::doSomething()'

    public int doSomething() {

      return 1;

    }

  }

  static class G {

    public static volatile A a = new A();

    // Change 'a' to point to a 'B' object

    public static void setAtoB() {

      try {

        a =  (A) ClassLoader.

                getSystemClassLoader().

                loadClass("B").

                getConstructor(new Class[] {}).

                newInstance(new Object[] {});

      }

      catch (Exception e) {

        System.out.println(e);

      }

    }

  }

  public static volatile boolean is_in_loop = false;

  public static volatile boolean stop_while_loop = false;

  public static double deopt_compiledframe_at_safepoint() {

    // This will be an optimised static call to A::doSomething() until we load "B"

    int i = G.a.doSomething();

    // Need more than 16 'double' locals in this frame

    double local1 = 1;

    double local2 = 2;

    double local3 = 3;

    double local4 = 4;

    double local5 = 5;

    double local6 = 6;

    double local7 = 7;

    double local8 = 8;

    long k = 0;

    // Once we load "B", this method will be made 'not entrant' and deoptimised

    // at the safepoint which is at the end of this loop.

    while (!stop_while_loop) {

      if (k ==  1) local1 += i;

      if (k ==  2) local2 += i;

      if (k ==  3) local3 += i;

      if (k ==  4) local4 += i;

      if (k ==  5) local5 += i;

      if (k ==  6) local6 += i;

      if (k ==  7) local7 += i;

      if (k ==  8) local8 += i;

      // Tell the world that we're now running wild in the loop

      if (k++ == 20000) is_in_loop = true;

    }

    return

      local1 + local2 + local3 + local4 +

      local5 + local6 + local7 + local8 + i;

  }

  public static void main(String[] args) {

    // Just to resolve G before we compile deopt_compiledframe_at_safepoint()

    G g = new G();

    // Asynchronous thread which will eventually invalidate the code for

    // deopt_compiledframe_at_safepoint() and therefore triggering a

    // deoptimisation of that method.

    new Thread() {

      public void run() {

        while (!is_in_loop) {

          // Wait until the loop is running

        }

        // Load class 'B' asynchronously..

        G.setAtoB();

        // ..and stop the loop

        stop_while_loop = true;

      }

    }.start();

    // Run the loop in deopt_compiledframe_at_safepoint()

    double retVal = deopt_compiledframe_at_safepoint();

    System.out.println(retVal == 36 ? "OK" : "ERROR : " + retVal);

    if (retVal != 36) throw new RuntimeException();

  }

}