8356255: Add Stable Field Updaters to allow efficient lazy field evaluations

make/test/BuildMicrobenchmark.gmk

@@ -92,6 +92,7 @@ $(eval $(call SetupJavaCompilation, BUILD_JDK_MICROBENCHMARK, \
         --add-exports java.base/jdk.internal.classfile.impl=ALL-UNNAMED \
         --add-exports java.base/jdk.internal.event=ALL-UNNAMED \
         --add-exports java.base/jdk.internal.foreign=ALL-UNNAMED \
+        --add-exports java.base/jdk.internal.lang.stable=ALL-UNNAMED \
         --add-exports java.base/jdk.internal.misc=ALL-UNNAMED \
         --add-exports java.base/jdk.internal.util=ALL-UNNAMED \
         --add-exports java.base/jdk.internal.vm=ALL-UNNAMED \

src/java.base/share/classes/java/lang/reflect/Method.java

@@ -26,6 +26,8 @@
 package java.lang.reflect;
 
 import jdk.internal.access.SharedSecrets;
+import jdk.internal.lang.stable.StableFieldUpdater;
+import jdk.internal.misc.Unsafe;
 import jdk.internal.misc.VM;
 import jdk.internal.reflect.CallerSensitive;
 import jdk.internal.reflect.CallerSensitiveAdapter;
@@ -47,6 +49,7 @@
 import java.lang.annotation.AnnotationFormatError;
 import java.nio.ByteBuffer;
 import java.util.StringJoiner;
+import java.util.function.ToIntFunction;
 
 /**
  * A {@code Method} provides information about, and access to, a single method
@@ -93,7 +96,19 @@ public final class Method extends Executable {
     private Method root;
     private transient volatile MethodRepository genericInfo;
     private @Stable MethodAccessor methodAccessor;
+
+    private static final ToIntFunction<Method> HASH_UPDATER =
+            StableFieldUpdater.Raw.ofInt(Method.class, Unsafe.getUnsafe().objectFieldOffset(Method.class, "hash"), new ToIntFunction<Method>() {
+                @Override
+                public int applyAsInt(Method method) {
+                    return method.getDeclaringClass().getName().hashCode() ^ method.getName()
+                            .hashCode();
+                }
+            }, 0); // The `hashCode()` is specified so, zeroReplacement is 0
     // End shared states
+
+    // Used reflectively via HASH_UPDATER
+    @Stable
     private int hash; // not shared right now, eligible if expensive
 
     // Generics infrastructure
@@ -360,13 +375,7 @@ public boolean equals(Object obj) {
      * method's declaring class name and the method's name.
      */
     public int hashCode() {
-        int hc = hash;
-
-        if (hc == 0) {
-            hc = hash = getDeclaringClass().getName().hashCode() ^ getName()
-                .hashCode();
-        }
-        return hc;
+        return HASH_UPDATER.applyAsInt(this);
     }
 
     /**

src/java.base/share/classes/java/net/URI.java

@@ -40,8 +40,13 @@
 import java.nio.charset.CharacterCodingException;
 import java.nio.file.Path;
 import java.text.Normalizer;
+import java.util.function.ToIntFunction;
+
 import jdk.internal.access.JavaNetUriAccess;
 import jdk.internal.access.SharedSecrets;
+import jdk.internal.lang.stable.StableFieldUpdater;
+import jdk.internal.vm.annotation.ForceInline;
+import jdk.internal.vm.annotation.Stable;
 import sun.nio.cs.UTF_8;
 
 /**
@@ -544,6 +549,13 @@ public final class URI
     // The remaining fields may be computed on demand, which is safe even in
     // the face of multiple threads racing to initialize them
     private transient String schemeSpecificPart;
+
+    private static final ToIntFunction<URI> HASH_UPDATER = StableFieldUpdater.ofInt(
+            URI.class, "hash", new ToIntFunction<>() {
+                @ForceInline @Override public int applyAsInt(URI uri) { return uri.hashCode0(); }}, -1);
+
+    // Used reflectively by HASH_UPDATER
+    @Stable
     private transient int hash;        // Zero ==> undefined
 
     private transient String decodedUserInfo;
@@ -1575,25 +1587,24 @@ public boolean equals(Object ob) {
      * @return  A hash-code value for this URI
      */
     public int hashCode() {
-        int h = hash;
-        if (h == 0) {
-            h = hashIgnoringCase(0, scheme);
-            h = hash(h, fragment);
-            if (isOpaque()) {
-                h = hash(h, schemeSpecificPart);
+        return HASH_UPDATER.applyAsInt(this);
+    }
+
+    private int hashCode0() {
+        int h = 0;
+        h = hashIgnoringCase(0, scheme);
+        h = hash(h, fragment);
+        if (isOpaque()) {
+            h = hash(h, schemeSpecificPart);
+        } else {
+            h = hash(h, path);
+            h = hash(h, query);
+            if (host != null) {
+                h = hash(h, userInfo);
+                h = hashIgnoringCase(h, host);
+                h += 1949 * port;
             } else {
-                h = hash(h, path);
-                h = hash(h, query);
-                if (host != null) {
-                    h = hash(h, userInfo);
-                    h = hashIgnoringCase(h, host);
-                    h += 1949 * port;
-                } else {
-                    h = hash(h, authority);
-                }
-            }
-            if (h != 0) {
-                hash = h;
+                h = hash(h, authority);
             }
         }
         return h;