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8283408: Fix a C2 crash when filling arrays with unsafe
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Reviewed-by: roland, thartmann
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Pengfei Li committed Mar 24, 2022
1 parent 1a84d75 commit a6740c0
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Showing 2 changed files with 73 additions and 3 deletions.
13 changes: 10 additions & 3 deletions src/hotspot/share/opto/loopTransform.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -4047,10 +4047,17 @@ bool PhaseIdealLoop::intrinsify_fill(IdealLoopTree* lpt) {
index = new LShiftXNode(index, shift->in(2));
_igvn.register_new_node_with_optimizer(index);
}
index = new AddPNode(base, base, index);
_igvn.register_new_node_with_optimizer(index);
Node* from = new AddPNode(base, index, offset);
Node* from = new AddPNode(base, base, index);
_igvn.register_new_node_with_optimizer(from);
// For normal array fills, C2 uses two AddP nodes for array element
// addressing. But for array fills with Unsafe call, there's only one
// AddP node adding an absolute offset, so we do a NULL check here.
assert(offset != NULL || C->has_unsafe_access(),
"Only array fills with unsafe have no extra offset");
if (offset != NULL) {
from = new AddPNode(base, from, offset);
_igvn.register_new_node_with_optimizer(from);
}
// Compute the number of elements to copy
Node* len = new SubINode(head->limit(), head->init_trip());
_igvn.register_new_node_with_optimizer(len);
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63 changes: 63 additions & 0 deletions test/hotspot/jtreg/compiler/loopopts/FillArrayWithUnsafe.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,63 @@
/*
* Copyright (c) 2022, Arm Limited. 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 8283408
* @summary Fill a byte array with Java Unsafe API
* @run main/othervm -XX:+OptimizeFill compiler.loopopts.FillArrayWithUnsafe
*/

package compiler.loopopts;

import java.lang.reflect.Field;

import sun.misc.Unsafe;

public class FillArrayWithUnsafe {

private static Unsafe unsafe;

public static void main(String[] args) throws Exception {
Class klass = Unsafe.class;
Field field = klass.getDeclaredField("theUnsafe");
field.setAccessible(true);
unsafe = (Unsafe) field.get(null);

byte[] buffer;
// Make sure method newByteArray is compiled by C2
for (int i = 0; i < 50000; i++) {
buffer = newByteArray(100, (byte) 0x80);
}
}

public static byte[] newByteArray(int size, byte val) {
byte[] arr = new byte[size];
int offset = unsafe.arrayBaseOffset(byte[].class);
for (int i = offset; i < offset + size; i++) {
unsafe.putByte(arr, i, val);
}
return arr;
}
}

5 comments on commit a6740c0

@openjdk-notifier
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@TheRealMDoerr
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/backport jdk17u-dev

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@openjdk openjdk bot commented on a6740c0 Mar 29, 2022

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@TheRealMDoerr the backport was successfully created on the branch TheRealMDoerr-backport-a6740c01 in my personal fork of openjdk/jdk17u-dev. To create a pull request with this backport targeting openjdk/jdk17u-dev:master, just click the following link:

➡️ Create pull request

The title of the pull request is automatically filled in correctly and below you find a suggestion for the pull request body:

Hi all,

This pull request contains a backport of commit a6740c01 from the openjdk/jdk repository.

The commit being backported was authored by Pengfei Li on 24 Mar 2022 and was reviewed by Roland Westrelin and Tobias Hartmann.

Thanks!

If you need to update the source branch of the pull then run the following commands in a local clone of your personal fork of openjdk/jdk17u-dev:

$ git fetch https://github.com/openjdk-bots/jdk17u-dev TheRealMDoerr-backport-a6740c01:TheRealMDoerr-backport-a6740c01
$ git checkout TheRealMDoerr-backport-a6740c01
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk17u-dev TheRealMDoerr-backport-a6740c01

@GoeLin
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@GoeLin GoeLin commented on a6740c0 Apr 6, 2022

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/backport jdk11u-dev

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@openjdk openjdk bot commented on a6740c0 Apr 6, 2022

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@GoeLin the backport was successfully created on the branch GoeLin-backport-a6740c01 in my personal fork of openjdk/jdk11u-dev. To create a pull request with this backport targeting openjdk/jdk11u-dev:master, just click the following link:

➡️ Create pull request

The title of the pull request is automatically filled in correctly and below you find a suggestion for the pull request body:

Hi all,

This pull request contains a backport of commit a6740c01 from the openjdk/jdk repository.

The commit being backported was authored by Pengfei Li on 24 Mar 2022 and was reviewed by Roland Westrelin and Tobias Hartmann.

Thanks!

If you need to update the source branch of the pull then run the following commands in a local clone of your personal fork of openjdk/jdk11u-dev:

$ git fetch https://github.com/openjdk-bots/jdk11u-dev GoeLin-backport-a6740c01:GoeLin-backport-a6740c01
$ git checkout GoeLin-backport-a6740c01
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk11u-dev GoeLin-backport-a6740c01

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