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8372002: VarHandle for receiver's superclass instance fields fails describeConstable

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Reviewed-by: psandoz, jvernee
This commit is contained in:
Chen Liang 2025-11-18 15:14:49 +00:00
parent b6d83eda6b
commit 1f99cf9424
4 changed files with 51 additions and 15 deletions
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13
src/java.base/share/classes/java/lang/invoke/VarHandles.java
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@ -166,12 +166,15 @@ final class VarHandles {
static Field getFieldFromReceiverAndOffset(Class<?> receiverType,
long offset,
Class<?> fieldType) {
for (Field f : receiverType.getDeclaredFields()) {
if (Modifier.isStatic(f.getModifiers())) continue;
// The receiver may be a referenced class different from the declaring class
for (var declaringClass = receiverType; declaringClass != null; declaringClass = declaringClass.getSuperclass()) {
for (Field f : declaringClass.getDeclaredFields()) {
if (Modifier.isStatic(f.getModifiers())) continue;
if (offset == UNSAFE.objectFieldOffset(f)) {
assert f.getType() == fieldType;
return f;
if (offset == UNSAFE.objectFieldOffset(f)) {
assert f.getType() == fieldType;
return f;
}
}
}
throw new InternalError("Field not found at offset");

45
test/jdk/java/lang/invoke/VarHandles/describeConstable/DescribeConstableTest.java
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2023, 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
@ -21,18 +21,16 @@
* questions.
*/
/**
/*
* @test
* @bug 8302260
* @bug 8302260 8372002
* @build p.C p.D p.I p.q.Q
* @run junit DescribeConstableTest
* @summary Test VarHandle::describeConstable on static fields
*/
import java.lang.constant.ClassDesc;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodHandles.Lookup;
import java.lang.invoke.VarHandle;
import java.lang.invoke.VarHandle.VarHandleDesc;
import java.util.stream.Stream;
@ -43,7 +41,7 @@ import static org.junit.jupiter.api.Assertions.*;
public class DescribeConstableTest {
private static final Lookup LOOKUP = MethodHandles.lookup();
private static Stream<Arguments> testCases() {
private static Stream<Arguments> staticTestCases() {
return Stream.of(
// static field defined in p.C only
Arguments.of(p.C.class, "cString", String.class, p.C.class, "CClass"),
@ -68,8 +66,8 @@ public class DescribeConstableTest {
}
@ParameterizedTest
@MethodSource("testCases")
void test(Class<?> refc, String name, Class<?> type, Class<?> declaringClass, Object value) throws Throwable {
@MethodSource("staticTestCases")
void testStatic(Class<?> refc, String name, Class<?> type, Class<?> declaringClass, Object value) throws Throwable {
var vh = LOOKUP.findStaticVarHandle(refc, name, type);
assertEquals(value, vh.get());
@ -84,6 +82,37 @@ public class DescribeConstableTest {
assertEquals(vhd.toString(), varHandleDescString(declaringClass, name, type, true));
}
private static Arguments[] instanceTestCases() {
return new Arguments[] {
// Basic instance field in p.q.Q
Arguments.of(p.q.Q.class, "instanceIntField", int.class, new p.q.Q(), 42),
// p.C.instanceIntField hides the superclass instanceIntField, but it still exists
Arguments.of(p.C.class, "instanceIntField", int.class, new p.C(), 76),
Arguments.of(p.q.Q.class, "instanceIntField", int.class, new p.C(), 42),
// p.D.instanceIntField points to that of p.q.Q
Arguments.of(p.D.class, "instanceIntField", int.class, new p.D(), 42),
};
}
@ParameterizedTest
@MethodSource("instanceTestCases")
void testInstance(Class<?> refc, String name, Class<?> type, Object instance, Object value) throws Throwable {
var vh = LOOKUP.findVarHandle(refc, name, type).withInvokeBehavior();
assertEquals(value, vh.get(instance));
var refcDesc = refc.describeConstable().orElseThrow();
var typeDesc = type.describeConstable().orElseThrow();
var vhd = vh.describeConstable().orElseThrow();
var vhd2 = VarHandleDesc.ofField(refcDesc, name, typeDesc);
assertEquals(value, vhd.resolveConstantDesc(LOOKUP).get(instance));
assertEquals(value, vhd2.resolveConstantDesc(LOOKUP).get(instance));
// The string does not use the declaring class because
// receiver is restricted on the handle
assertEquals(vhd.toString(), varHandleDescString(refc, name, type, false));
}
static String varHandleDescString(Class<?> declaringClass, String name, Class<?> type, boolean staticField) {
return String.format("VarHandleDesc[%s%s.%s:%s]",
staticField ? "static " : "",

4
test/jdk/java/lang/invoke/VarHandles/describeConstable/p/C.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2023, 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
@ -25,4 +25,6 @@ package p;
public class C extends p.q.Q implements I {
public static String cString = "CClass";
public int instanceIntField = 76; // Hides the field from Q
}

4
test/jdk/java/lang/invoke/VarHandles/describeConstable/p/q/Q.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2023, 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
@ -29,4 +29,6 @@ public class Q {
public static String stringField2 = "QClass2";
public static long longField2 = 102L;
public int instanceIntField = 42;
}