8318626: GetClassFields does not filter out ConstantPool.constantPoolOop field

src/hotspot/share/runtime/reflectionUtils.hpp

@@ -214,20 +214,26 @@ class FilteredFieldStream : public FieldStream {
  private:
   int  _filtered_fields_count;
   bool has_filtered_field() { return (_filtered_fields_count > 0); }
+  void skip_filtered_fields() {
+    if (has_filtered_field()) {
+      while (_index >= 0 && FilteredFieldsMap::is_filtered_field((Klass*)_klass, offset())) {
+        _index -= 1;
+      }
+    }
+  }
 
  public:
   FilteredFieldStream(InstanceKlass* klass, bool local_only, bool classes_only)
     : FieldStream(klass, local_only, classes_only) {
     _filtered_fields_count = FilteredFieldsMap::filtered_fields_count(klass, local_only);
+    // skip filtered fields at the end
+    skip_filtered_fields();
+
   }
   int field_count();
   void next() {
     _index -= 1;
-    if (has_filtered_field()) {
-      while (_index >=0 && FilteredFieldsMap::is_filtered_field((Klass*)_klass, offset())) {
-        _index -= 1;
-      }
-    }
+    skip_filtered_fields();
   }
 };
 

test/hotspot/jtreg/serviceability/jvmti/GetClassFields/FilteredFields/FilteredFieldsTest.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2023, 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.
+ *
+ * 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.
+ */
+
+/*
+ * @test
+ * @bug 8318626
+ * @summary Verifies JVMTI GetClassFields function filters out fields
+ *          the same way Class.getDeclaredFields() does.
+ *
+ * @run main/othervm/native -agentlib:FilteredFieldsTest FilteredFieldsTest
+ */
+
+import java.lang.reflect.Field;
+
+public class FilteredFieldsTest {
+
+    static {
+        System.loadLibrary("FilteredFieldsTest");
+    }
+
+    private native static int getJVMTIFieldCount(Class cls);
+
+    private static int getDeclaredFieldsCount(Class cls) {
+        Field[] declaredFields = cls.getDeclaredFields();
+        System.out.println("Class.getDeclaredFields reported " + declaredFields.length + " fields:");
+        for (int i = 0; i < declaredFields.length; i++) {
+            System.out.println("  [" + i + "] : " + declaredFields[i]);
+        }
+        return declaredFields.length;
+    }
+
+    public static void main(String args[]) throws Exception {
+        Class cls = Class.forName("jdk.internal.reflect.ConstantPool");
+        int declaredCount = getDeclaredFieldsCount(cls);
+        int jvmtiCount = getJVMTIFieldCount(cls);
+        if (declaredCount != jvmtiCount) {
+            throw new Exception("declaredCount != jvmtiCount: " + declaredCount + " != " + jvmtiCount);
+        }
+    }
+}

test/hotspot/jtreg/serviceability/jvmti/GetClassFields/FilteredFields/libFilteredFieldsTest.cpp

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2023, 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.
+ *
+ * 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.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include "jvmti.h"
+#include "jvmti_common.h"
+
+extern "C" {
+
+static jvmtiEnv *jvmti = NULL;
+
+
+jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
+    jint res = jvm->GetEnv((void **)&jvmti, JVMTI_VERSION_1_1);
+    if (res != JNI_OK || jvmti == NULL) {
+        printf("Wrong result of a valid call to GetEnv!\n");
+        fflush(0);
+        return JNI_ERR;
+    }
+    return JNI_OK;
+}
+
+JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
+    return Agent_Initialize(jvm, options, reserved);
+}
+JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM *jvm, char *options, void *reserved) {
+    return Agent_Initialize(jvm, options, reserved);
+}
+
+
+JNIEXPORT jint JNICALL
+Java_FilteredFieldsTest_getJVMTIFieldCount(JNIEnv *env, jclass cls, jclass clazz) {
+    if (jvmti == NULL) {
+        env->FatalError("JVMTI agent was not properly loaded");
+    }
+
+    jint fcount = 0;
+    jfieldID *fields = nullptr;
+
+    check_jvmti_status(env, jvmti->GetClassFields(clazz, &fcount, &fields), "GetClassFields failed");
+
+    printf("GetClassFields returned %d fields:\n", (int)fcount);
+    for (int i = 0; i < fcount; i++) {
+        char *name;
+        jvmtiError err = jvmti->GetFieldName(clazz, fields[i], &name, nullptr, nullptr);
+        if (err != JVMTI_ERROR_NONE) {
+            printf("GetFieldName(%d) returned error: %s (%d)\n",
+                   i, TranslateError(err), err);
+            continue;
+        }
+        printf("  [%d]: %s\n", i, name);
+        jvmti->Deallocate((unsigned char *)name);
+    }
+    fflush(0);
+    return fcount;
+}
+
+}