commit 524c60670a939e1e814ff232af2d0a4d6b2365ff
author Damien Neil <dneil@google.com> Tue Jan 28 13:32:01 2020 -0800
committer Damien Neil <dneil@google.com> Tue Jan 28 23:33:31 2020 +0000
tree fcefaa3ca2acf6cf751631b40a2d21b1f58aeab3
parent 212b05b8089ca06b9230f97b5d5c117bdfb97868

runtime/protoiface: use more efficient options representation

Change the representation of option flags in protoiface from bools to a
bitfield. This brings the representation of options in protoiface in
sync with that in internal/impl.

This change has several benefits:

1. We will probably find that we need to add more option flags over time.
Converting to the more efficient representation of these flags as high
in the call stack as possible minimizes the performance implication of
the struct growing.

2. On a similar note, this avoids the need to convert from the compact
representation to the larger one when passing from internal/impl to
proto, since the {Marshal,Unmarshal}State methods take the compact form.

3. This removes unused options from protoiface. Instead of documenting
that AllowPartial is always set, we can just not include an AllowPartial
flag in the protoiface options.

4. Conversely, this provides a way to add option flags to protoiface
that we don't want to expose in the proto package.

name                             old time/op    new time/op    delta
EmptyMessage/Wire/Marshal-12       11.1ns ± 7%    10.1ns ± 1%   -9.35%  (p=0.000 n=8+8)
EmptyMessage/Wire/Unmarshal-12     7.07ns ± 0%    6.74ns ± 1%   -4.58%  (p=0.000 n=8+8)
EmptyMessage/Wire/Validate-12      4.30ns ± 1%    3.80ns ± 8%  -11.45%  (p=0.000 n=7+8)
RepeatedInt32/Wire/Marshal-12      1.17µs ± 1%    1.21µs ± 7%   +4.09%  (p=0.000 n=8+8)
RepeatedInt32/Wire/Unmarshal-12     938ns ± 0%     942ns ± 3%     ~     (p=0.178 n=7+8)
RepeatedInt32/Wire/Validate-12      521ns ± 4%     543ns ± 7%     ~     (p=0.157 n=7+8)
Required/Wire/Marshal-12           97.2ns ± 1%    95.3ns ± 1%   -1.98%  (p=0.001 n=7+7)
Required/Wire/Unmarshal-12         41.0ns ± 9%    38.6ns ± 3%   -5.73%  (p=0.048 n=8+8)
Required/Wire/Validate-12          25.4ns ±11%    21.4ns ± 3%  -15.62%  (p=0.000 n=8+7)

Change-Id: I3ac1b00ab36cfdf61316ec087a5dd20d9248e4f6
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/216760
Reviewed-by: Joe Tsai <joetsai@google.com>