RFR: 8297379: Enable the ByteBuffer path of Poly1305 optimizations

[Jatin Bhateja]

On Wed, 23 Nov 2022 23:33:32 GMT, Volodymyr Paprotski <duke at openjdk.org> wrote:

> Regarding mainline:
> - I decided not to 'unroll' the top while loop (i.e. `engineUpdate(byte[] input, int offset, int len)` is unrolled)
>    - It is debatable which version is easier to understand. If this version is 'too complex', I can unroll the top while loop. 
> - I do think this version is incremental (i.e. easier to review?):
>    - Move `remaining -= bytesToWrite;` into each `if` branch
>    - Change first `if` case to process multiple blocks instead of one
> 
> This `while` loop has a lot of cases to remember; Very roughly:
> 
> 1. process from previous call
> 2. process current data
> 3. store overflow
> 
> Interesting situations:
> - `blockOffset` might be non-`0`
> - `remaining+blockOffset` might not be enough to fill a single block. Or just enough for one block and to leave an overflow again..
> - etc.
> 
> Regarding testing
> - Correctness of intrinsic was already tested in https://github.com/openjdk/jdk/pull/10582 so not adding any tests there (i.e. no KAT)
> - In principle, fuzz test should also be sufficient to test bytebuffer (did increase repetitions)

Please add a JMH micro showcasing gains, with heap allocated and native byte buffer (once you support it).

src/java.base/share/classes/com/sun/crypto/provider/Poly1305.java line 268:

> 266:         } else {
> 267:             while (blockMultipleLength > 0) {
> 268:                 processBlock(buf, BLOCK_LENGTH);

For native byte buffers, you can pass the buffer address and base.

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PR: https://git.openjdk.org/jdk/pull/11338