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 package jdk.vm.ci.meta;
  24 
  25 import java.util.*;
  26 import java.util.concurrent.*;
  27 
  28 /**
  29  * Manages a list of unique deoptimization reasons.


  30  *


  31  */
  32 public abstract class SpeculationLog {
  33     private volatile Object lastFailed;
  34     private volatile Collection<Object> speculations;
  35     private Set<Object> failedSpeculations;
  36 
  37     public synchronized void collectFailedSpeculations() {
  38         if (lastFailed != null) {
  39             if (failedSpeculations == null) {
  40                 failedSpeculations = new HashSet<>(2);
  41             }
  42             failedSpeculations.add(lastFailed);
  43             lastFailed = null;
  44             speculations = null;
  45         }
  46     }
  47 
  48     public boolean maySpeculate(Object reason) {
  49         if (failedSpeculations != null && failedSpeculations.contains(reason)) {
  50             return false;
  51         }
  52         return true;
  53     }
  54 
  55     protected void addSpeculation(Object reason) {
  56         assert maySpeculate(reason);
  57         if (speculations == null) {
  58             synchronized (this) {
  59                 if (speculations == null) {
  60                     speculations = new ConcurrentLinkedQueue<>();
  61                 }
  62             }
  63         }
  64         speculations.add(reason);
  65     }
  66 
  67     public abstract JavaConstant speculate(Object reason);






  68 }

   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 package jdk.vm.ci.meta;
  24 



  25 /**
  26  * Manages unique deoptimization reasons. Reasons are embedded in compiled code and can be
  27  * invalidated at run time. Subsequent compilations then should not speculate again on such
  28  * invalidated reasons to avoid repeated deoptimization.
  29  *
  30  * All methods of this interface are called by the compiler. There is no need for API to register
  31  * failed speculations during deoptimization, since every VM has different needs there.
  32  */
  33 public interface SpeculationLog {



  34 
  35     /**
  36      * Marker interface for speculation objects that can be added to the speculation log.
  37      */
  38     public interface SpeculationReason {





  39     }
  40 
  41     /**
  42      * Must be called before compilation, i.e., before a compiler calls {@link #maySpeculate}.
  43      */
  44     void collectFailedSpeculations();


  45 
  46     /**
  47      * If this method returns true, the compiler is allowed to {@link #speculate} with the given
  48      * reason.
  49      */
  50     boolean maySpeculate(SpeculationReason reason);






  51 
  52     /**
  53      * Registers a speculation that was performed by the compiler.
  54      *
  55      * @return A compiler constant encapsulating the provided reason. It is usually passed as an
  56      *         argument to the deoptimization function.
  57      */
  58     JavaConstant speculate(SpeculationReason reason);
  59 }