commit 9015c75c5921e3fc3f90a506db48537f40ae1cc6
author Benjamin Prosnitz <bprosnitz@google.com> Tue Jul 14 11:33:42 2020 +0000
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> Tue Jul 14 11:33:42 2020 +0000
tree a8107bd1cfc1a0f476ae539db8819f6dd10b0794
parent 301308d034367a22bb48f1fbabdb891cd26a8784

[fidl][rust] Use fidl_struct_copy! macro where possible

fidl_struct_copy! is a new rust macro that directly copies structs when:
- There is no padding
- The struct entirely consists of primitives and structs consisting of
primitives (recursively)

It is potentially possible to extend this to structs containing arrays,
which would be useful for types like MessageHeader but it is not
currently supported by zerocopy.

This reduces binary size by 20480 bytes

Summary of performance change: (others have small percentage difference)
Rust/Decode/MessageHeader/WallTime                                                       faster            0.462-0.471    80.88 +/- 0.12 ns     37.76 +/- 0.30 ns
Rust/Decode/StructField/16/WallTime                                                      faster            0.198-0.203    186.24 +/- 0.13 ns    37.27 +/- 0.46 ns
Rust/Decode/StructField/256/WallTime                                                     faster            0.019-0.021    2813 +/- 12 ns        56.7 +/- 1.8 ns
Rust/Decode/StructTree/Depth8/WallTime                                                   faster            0.010-0.011    5571.7 +/- 7.9 ns     58.3 +/- 1.3 ns
Rust/Encode/MessageHeader/WallTime                                                       faster            0.608-0.617    87.73 +/- 0.38 ns     53.76 +/- 0.17 ns
Rust/Encode/StructField/16/WallTime                                                      faster            0.334-0.338    166.90 +/- 0.33 ns    56.06 +/- 0.26 ns
Rust/Encode/StructField/256/WallTime                                                     faster            0.033-0.034    1908.4 +/- 3.5 ns     63.99 +/- 0.24 ns
Rust/Encode/StructTree/Depth8/WallTime                                                   faster            0.021-0.021    3002.8 +/- 2.9 ns     62.66 +/- 0.29 ns


Test: existing rust conformance tests

Change-Id: I2ca8eb624b36011f0835e09a207fb3d62d626b48
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/403333
Reviewed-by: Tyler Mandry <tmandry@google.com>
Reviewed-by: Mitchell Kember <mkember@google.com>
Commit-Queue: Benjamin Prosnitz <bprosnitz@google.com>
Testability-Review: Mitchell Kember <mkember@google.com>