svm: adopt "JDK-8351594: JFR: Rate-limited sampling of Java events"

Author: zapster

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/truffle/KnownTruffleTypes.java

@@ -221,7 +221,7 @@ private static ResolvedJavaField getThrowableJFRTracingField(MetaAccessProvider
         ResolvedJavaType throwableType = metaAccess.lookupJavaType(Throwable.class);
         for (ResolvedJavaField staticField : throwableType.getStaticFields()) {
             if (staticField.getName().equals("jfrTracing") &&
-                            staticField.getType().equals(metaAccess.lookupJavaType(boolean.class)) && staticField.isVolatile()) {
+                            staticField.getType().equals(metaAccess.lookupJavaType(boolean.class))) {
                 return staticField;
             }
         }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jfr/Target_jdk_jfr_internal_settings_Throttler.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2025, 2025, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.svm.core.jfr;
+
+import java.util.Random;
+
+import com.oracle.svm.core.annotate.Alias;
+import com.oracle.svm.core.annotate.InjectAccessors;
+import com.oracle.svm.core.annotate.TargetClass;
+
+@TargetClass(className = "jdk.jfr.internal.settings.Throttler")
+public final class Target_jdk_jfr_internal_settings_Throttler {
+    @Alias //
+    @InjectAccessors(ThrottlerRandomAccessor.class) //
+    private Random randomGenerator;
+}
+
+final class ThrottlerRandomAccessor {
+    private static Random cachedRandom;
+
+    @SuppressWarnings("unused")
+    static Random get(Target_jdk_jfr_internal_settings_Throttler receiver) {
+        if (cachedRandom != null) {
+            return cachedRandom;
+        }
+        return initializeRandom();
+    }
+
+    private static synchronized Random initializeRandom() {
+        if (cachedRandom != null) {
+            return cachedRandom;
+        }
+
+        cachedRandom = new Random();
+        return cachedRandom;
+    }
+
+    @SuppressWarnings("unused")
+    static synchronized void set(Target_jdk_jfr_internal_settings_Throttler receiver, Random value) {
+        throw new RuntimeException("The field jdk.jfr.internal.settings.Throttler.randomGenerator cannot be set");
+    }
+}