src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotJVMCIMetaAccessContext.java

rev 54629 : [mq]: 8218700

*** 1,7 ****
  /*
!  * Copyright (c) 2015, 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.
--- 1,7 ----
  /*
!  * Copyright (c) 2015, 2019, 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.
*** 143,177 ****
          } else {
              return new HotSpotResolvedObjectTypeImpl(javaClass, this);
          }
      }
  
!     private final ClassValue<WeakReference<ResolvedJavaType>> resolvedJavaType = new ClassValue<>() {
          @Override
!         protected WeakReference<ResolvedJavaType> computeValue(Class<?> type) {
!             return new WeakReference<>(createClass(type));
          }
      };
  
      /**
       * Gets the JVMCI mirror for a {@link Class} object.
       *
       * @return the {@link ResolvedJavaType} corresponding to {@code javaClass}
       */
      public ResolvedJavaType fromClass(Class<?> javaClass) {
!         ResolvedJavaType javaType = null;
!         while (javaType == null) {
!             WeakReference<ResolvedJavaType> type = resolvedJavaType.get(javaClass);
!             javaType = type.get();
              if (javaType == null) {
                  /*
!                  * If the referent has become null, clear out the current value and let computeValue
!                  * above create a new value. Reload the value in a loop because in theory the
!                  * WeakReference referent can be reclaimed at any point.
                   */
!                 resolvedJavaType.remove(javaClass);
!             }
          }
          return javaType;
      }
  
      /**
--- 143,187 ----
          } else {
              return new HotSpotResolvedObjectTypeImpl(javaClass, this);
          }
      }
  
!     private static class WeakTypeRef {
!         private WeakReference<ResolvedJavaType> ref;
!         WeakTypeRef(ResolvedJavaType value) {
!             set(value);
!         }
!         void set(ResolvedJavaType value) {
!             ref = new WeakReference<ResolvedJavaType>(value);
!         }
!         ResolvedJavaType get() {
!             return ref.get();
!         }
!     };
! 
!     private final ClassValue<WeakTypeRef> resolvedJavaType = new ClassValue<>() {
          @Override
!         protected WeakTypeRef computeValue(Class<?> type) {
!             return new WeakTypeRef(createClass(type));
          }
      };
  
      /**
       * Gets the JVMCI mirror for a {@link Class} object.
       *
       * @return the {@link ResolvedJavaType} corresponding to {@code javaClass}
       */
      public ResolvedJavaType fromClass(Class<?> javaClass) {
!         WeakTypeRef ref = resolvedJavaType.get(javaClass);
!         ResolvedJavaType javaType = ref.get();
          if (javaType == null) {
              /*
!              * If the referent has become null, create a new value and
!              * update cached weak reference.
               */
!             javaType = createClass(javaClass);
!             ref.set(javaType);
          }
          return javaType;
      }
  
      /**