[jdk8u-dev] RFR: 6899049: G1: Clean up code in ptrQueue.[ch]pp and ptrQueue.inline.hpp [v4]

[Paul Hohensee]

On Wed, 27 Sep 2023 14:06:30 GMT, Sun Jianye <jianyesun at openjdk.org> wrote:

>> Hi all,
>> 
>> This pull request contains a backport of commit [b256989eb34a32c8f03be448c0645baeb5192a01](https://github.com/openjdk/jdk11u-dev/commit/b256989eb34a32c8f03be448c0645baeb5192a01) from the [openjdk/jdk11u-dev](https://github.com/openjdk/jdk11u-dev) repository.
>> 
>> As reported by issue :  https://bugs.openjdk.org/browse/JDK-8316278 .  We found  the indexing method of PtrQueue's buf  is not  correct  when  converting an integer of type size_t to type int, then calling the method PtrQueue::byte_index_to_index . 
>> The key problem is this way of using: 
>> 
>> size_t i=0;    _buf[byte_index_to_index((int)i)] = NULL;  
>> 
>> The variable i of size_t type  cannot be converted directly to an int type . Other than that, the return value of the function byte_index_to_index is the index of the array _buf, and it should be non-negative. So it  should be a type of size_t. 
>> Currently we have found 2 issues related to this problem,  https://bugs.openjdk.org/browse/JDK-8308169 and  https://bugs.openjdk.org/browse/JDK-8303961.  They are all triggered by a special  size number of buf, like '-XX:G1UpdateBufferSize=512M'  or  '-XX:G1SATBBufferSize=500m'
>> We also added a test case.
>> Please review this PR. Thanks.
>
> Sun Jianye has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - fix the return type
>  - remove extra spaces

White space mismatch in dirtyCardQueue.cpp, lines 209 and 210. dirtyCardQueue.hpp ine 72 also doesn't match, but Andrew allowed it so I will too. Other than that, lgtm.

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Changes requested by phh (Reviewer).

PR Review: https://git.openjdk.org/jdk8u-dev/pull/374#pullrequestreview-1688675128