RFR: 8283122: [AIX, s390] UnsafeCopyMemory 'Mismatched' Tests Fail on Big Endian Systems [v3]

[Roger Riggs]

On Tue, 15 Mar 2022 13:59:31 GMT, Tyler Steele <duke at openjdk.java.net> wrote:

>> This is a testbug present on big endian systems. UnsafeCopyMemory.java contains a few tests with 'mismatched' source and destination size. These tests use Unsafe.copyMemory to copy 4 bytes between longs and ints. The location of the bytes to be copied (if the copy comes from a long), or the offset into which the bytes should be copied (if the copy is into a long) are different on big and little endian systems.
>> 
>> Copying from a long to int on a little endian system, the bytes to be copied are those present at the long's address.
>> 
>> 
>> src: _ _ _ _ | _ _ _ _
>>      ^ ~ ~ ^ LE copy
>> dst: _ _ _ _
>> 
>> 
>> On BE systems, the bytes are offset by 4.
>> 
>> 
>> src: _ _ _ _ | _ _ _ _
>>                ^ ~ ~ ^ BE copy
>> dst: _ _ _ _
>> 
>> 
>> The situation for copying into a long from an int is analogous.
>> 
>> This PR adds the required offset for the 'mismatched copy' tests. With this change, UnsafeCopyMemory.java now passes on AIX and s390.
>
> Tyler Steele has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Removes unneeded bug label

test/hotspot/jtreg/compiler/unsafe/UnsafeCopyMemory.java line 2:

> 1: /*
> 2:  * Copyright (c) 2021, 2022 Oracle and/or its affiliates. All rights reserved.

The copyright is missing a "," after 2022.
Please file a new PR to fix.

-------------

PR: https://git.openjdk.java.net/jdk/pull/7811