RFR: 8248188: Add IntrinsicCandidate and API for Base64 decoding [v8]

[Vladimir Kozlov]

On Wed, 21 Oct 2020 20:43:30 GMT, CoreyAshford <github.com+51754783+CoreyAshford at openjdk.org> wrote:

>> This patch set encompasses the following commits:
>> 
>> - Adds a new HotSpot intrinsic candidate to the java.lang.Base64 class - decodeBlock(), and provides a flexible API for the intrinsic.  The API is similar to the existing encodeBlock intrinsic.
>> - Adds the code in HotSpot to check and martial the new intrinsic's arguments to the arch-specific intrinsic implementation
>> - Adds a Power64LE-specific implementation of the decodeBlock intrinsic.
>> - Adds a JMH microbenchmark for both Base64 encoding and encoding.
>> - Enhances the JTReg hotspot intrinsic "TestBase64.java" regression test to more fully test both decoding and encoding.
>
> CoreyAshford has updated the pull request incrementally with one additional commit since the last revision:
> 
>   TestBase64.java: remove jdk.test.lib.Utils from @build which was causing Tier3 failures.

Tier3 testing clean with updated test.

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Marked as reviewed by kvn (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/293