commit | 09c2e2dd0bb19bf72364438d64ce1989f458aacc | [log] [tgz] |
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author | Shoaib Meenai <smeenai@fb.com> | Fri Nov 12 15:33:21 2021 -0800 |
committer | Copybara-Service <copybara-worker@google.com> | Tue Nov 16 16:36:13 2021 -0800 |
tree | d1cd671feb8e7ef41d2720555712f5d76a40564c | |
parent | 0fe05b5545761378cc0f11894baefd57096fd15f [diff] |
[MachO] Reduce size of Symbol and Defined We can lay out Symbol more optimally to reduce its size from 56 bytes to 48 bytes by eliminating unnecessary padding, and we can lay out Defined such that its bitfield members are placed in the tail padding of Symbol (on ABIs which support this), to reduce it from 96 bytes to 80 bytes (8 bytes from the Symbol reduction, and 8 bytes from the tail padding reuse). This is perf-neutral for an internal app (results from two different machines): ``` smol-syms baseline difference (95% CI) sys_time 7.430 ± 0.202 7.440 ± 0.193 [ -2.6% .. +2.9%] user_time 21.443 ± 0.513 21.206 ± 0.396 [ -3.3% .. +1.1%] wall_time 20.453 ± 0.534 20.222 ± 0.488 [ -3.7% .. +1.5%] samples 9 8 smol-syms baseline difference (95% CI) sys_time 3.011 ± 0.050 3.040 ± 0.052 [ -0.4% .. +2.3%] user_time 10.416 ± 0.075 10.496 ± 0.091 [ +0.1% .. +1.4%] wall_time 12.229 ± 0.144 12.354 ± 0.192 [ -0.1% .. +2.1%] samples 14 13 ``` However, on the first machine, it reduces maximum resident set size by 65.9 MB (0.8%, from 7.92 GB to 7.85 GB). On the second machine, it reduces it by 92 MB (1.4%, from 6.40 GB to 6.31 GB). Reviewed By: #lld-macho, int3 Differential Revision: https://reviews.llvm.org/D113813 GitOrigin-RevId: 31952978970dcc3a2b91a0ac240d9ab06c06c856
This directory and its subdirectories contain source code for the LLVM Linker, a modular cross platform linker which is built as part of the LLVM compiler infrastructure project.
lld is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt.
In order to make sure various developers can evaluate patches over the same tests, we create a collection of self contained programs.
It is hosted at https://s3-us-west-2.amazonaws.com/linker-tests/lld-speed-test.tar.xz
The current sha256 is 10eec685463d5a8bbf08d77f4ca96282161d396c65bd97dc99dbde644a31610f
.