RFR: 8260337: Optimize ImageReader lookup, used by Class.getResource [v2]

[Jim Laskey]

On Mon, 25 Jan 2021 16:09:01 GMT, Claes Redestad <redestad at openjdk.org> wrote:

>> This patch optimizes the code paths exercised by `String.class.getResource("String.class")` by:
>> 
>> - Adding an ASCII fast-path to methods verifying strings in the jimage, which can then be done allocation-free
>> - Avoiding the allocation of the `long[8]` attributes when verifying only for the purpose of verifying a path exists
>> - Using the `JNUA.create` fast-path in `SystemModuleReader` (which should be OK since we just verified the given name is a JRT path)
>> - Remove a redundant check in `Class::resolveName` and fitting the `StringBuilder` to size
>
> Claes Redestad has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Copyrights and rename containsLocation

Nice clean up. LGTM

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Marked as reviewed by jlaskey (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/2212