tree 8c8d07fd858b1e4a39470800a8db6c868194eae1
parent 0967853d6800d57e704edfb9008fcbef4fef3b46
author David Benjamin <davidben@google.com> 1510191379 -0500
committer Adam Langley <agl@google.com> 1510347210 +0000

Remove custom memcpy and memset from poly1305_vec.

This avoids upsetting the C compiler. UBSan is offended by the alignment
violations in those functions. The business with offset is also
undefined behavior (pointer arithmetic is supposed to stay within a
single object).

There is a small performance cost, however:

Before:
Did 6636000 ChaCha20-Poly1305 (16 bytes) seal operations in 5000475us (1327073.9 ops/sec): 21.2 MB/s
Did 832000 ChaCha20-Poly1305 (1350 bytes) seal operations in 5003481us (166284.2 ops/sec): 224.5 MB/s
Did 155000 ChaCha20-Poly1305 (8192 bytes) seal operations in 5026933us (30833.9 ops/sec): 252.6 MB/s

After:
Did 6508000 ChaCha20-Poly1305 (16 bytes) seal operations in 5000160us (1301558.4 ops/sec): 20.8 MB/s
Did 831000 ChaCha20-Poly1305 (1350 bytes) seal operations in 5002865us (166104.8 ops/sec): 224.2 MB/s
Did 155000 ChaCha20-Poly1305 (8192 bytes) seal operations in 5013204us (30918.4 ops/sec): 253.3 MB/s

(Tested with the no-asm build which disables the custom stitched mode
assembly and ends up using this one.)

Change-Id: I76d74183f1e04ad3726463a8871ee64be04ce674
Reviewed-on: https://boringssl-review.googlesource.com/22784
Reviewed-by: Adam Langley <agl@google.com>