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8389234: [lworld] Bad cast for delayed access through abstract value class

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Reviewed-by: chagedorn, qamai
This commit is contained in:
Tobias Hartmann 2026-08-03 06:56:06 +00:00
parent d5da754c6e
commit 66259730f3
2 changed files with 82 additions and 4 deletions
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15
src/hotspot/share/c1/c1_GraphBuilder.cpp
View File

@ -1092,12 +1092,15 @@ void GraphBuilder::load_indexed(BasicType type) {
bool is_null_free = array_klass->is_elem_null_free();
bool will_link;
ciField* next_field = s.get_field(will_link);
bool next_needs_patching = !next_field->holder()->is_initialized() ||
ciInstanceKlass* next_holder = next_field->holder();
bool next_needs_patching = !next_holder->is_initialized() ||
!next_field->will_link(method(), Bytecodes::_getfield) ||
PatchALot;
bool needs_atomic_access = array_klass->is_elem_atomic();
// Offset adjustment for delayed reads requires a concrete inline holder
bool next_holder_is_inlinetype = next_holder->is_inlinetype();
can_delay_access = is_null_free && C1UseDelayedFlattenedFieldReads &&
!next_needs_patching && !needs_atomic_access;
!next_needs_patching && !needs_atomic_access && next_holder_is_inlinetype;
}
if (can_delay_access) {
// potentially optimizable array access, storing information for delayed decision
@ -1998,12 +2001,16 @@ void GraphBuilder::access_field(Bytecodes::Code code) {
s.next();
if (s.cur_bc() == Bytecodes::_getfield && !needs_patching) {
ciField* next_field = s.get_field(will_link);
bool next_needs_patching = !next_field->holder()->is_loaded() ||
ciInstanceKlass* next_holder = next_field->holder();
bool next_needs_patching = !next_holder->is_loaded() ||
!next_field->will_link(method(), Bytecodes::_getfield) ||
PatchALot;
// We can't update the offset for atomic accesses
bool next_needs_atomic_access = next_field->is_flat() && next_field->is_atomic();
can_delay_access = C1UseDelayedFlattenedFieldReads && !next_needs_patching && !next_needs_atomic_access && next_field->is_null_free();
// Offset adjustment for delayed reads requires a concrete inline holder
bool next_holder_is_inlinetype = next_holder->is_inlinetype();
can_delay_access = C1UseDelayedFlattenedFieldReads && !next_needs_patching && !next_needs_atomic_access &&
next_field->is_null_free() && next_holder_is_inlinetype;
}
}

71
test/hotspot/jtreg/compiler/valhalla/inlinetypes/TestAbstractDelayedAccess.java Normal file
View File

@ -0,0 +1,71 @@
/*
* Copyright (c) 2026, 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.
*/
package compiler.valhalla.inlinetypes;
import jdk.internal.vm.annotation.NullRestricted;
import jdk.test.lib.Asserts;
/*
* @test
* @bug 8389234
* @summary Test C1 delayed access with a field declared in an abstract value class.
* @library /test/lib
* @enablePreview
* @modules java.base/jdk.internal.vm.annotation
* @run main ${test.main.class}
* @run main/othervm -Xbatch -XX:TieredStopAtLevel=1
* ${test.main.class}
*/
public class TestAbstractDelayedAccess {
static abstract value class AbstractValue {
@NullRestricted
Integer i = 42;
}
static value class ConcreteValue extends AbstractValue { }
static class Holder {
@NullRestricted
ConcreteValue value;
Holder() {
value = new ConcreteValue();
super();
}
}
// Loading h.value starts a delayed flat field access. Resolving AbstractValue.i
// while it is pending must not cast the AbstractValue holder to ciInlineKlass.
static int test(Holder h) {
return h.value.i;
}
public static void main(String[] args) {
Holder h = new Holder();
for (int i = 0; i < 20_000; i++) {
Asserts.assertEQ(test(h), 42);
}
}
}