| commit | 207400cee176a4f71c3b595ae880dc62cd632c06 | [log] [tgz] |
|---|---|---|
| author | David 'Digit' Turner <digit@google.com> | Thu May 07 01:33:04 2020 +0200 |
| committer | Commit Bot <commit-bot@chromium.org> | Fri May 08 18:06:39 2020 +0000 |
| tree | 0c9be7d4c33e08ca97c6cf4e4599e4fa5b4bec28 | |
| parent | 16ab9cab9f4768ad84b9afb2c6e24dd76e3e2c56 [diff] |
build/gen.py: Add --link-lib=LINK_LIB option.
This adds one new command-line option to the build/gen.py
script to allow linking the final executable(s) with one or
more extra libraries.
This is mostly useful to link a custom malloc implementation
or a cpu profiling library, like libtcmalloc.a or libprofiler.a
provided by the the gperftools project [1].
For the record, using:
build/gen.py --use-icf --use-lto --link-lib=/path/to/libtcmalloc.a
Results in a noticeably faster GN executable for both Chromium
(21% faster) and the Fuchsia build (43% faster!)
It is also possible to link against a more recent release of TCMalloc
from [2], but measurements show no noticeable performance difference
with the older release for GN workloads.
Chromium:
BEFORE: Done. Made 13124 targets from 2289 files in 3593ms
AFTER: Done. Made 13124 targets from 2289 files in 4358ms
Fuchsia:
BEFORE: [...] Done. Made 47263 targets from 3819 files in 14263ms
AFTER: [...] Done. Made 47263 targets from 3819 files in 9923ms
[1] https://github.com/gperftools/gperftools
[2] https://github.com/google/tcmalloc
Change-Id: If21911f13a886eeae09797099a078ed1d4f789dd
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/8360
Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: David Turner <digit@google.com>
GN is a meta-build system that generates build files for Ninja.
Related resources:
You can download the latest version of GN binary for Linux, macOS and Windows.
Alternatively, you can build GN from source:
git clone https://gn.googlesource.com/gn cd gn python build/gen.py ninja -C out # To run tests: out/gn_unittests
On Windows, it is expected that cl.exe, link.exe, and lib.exe can be found in PATH, so you'll want to run from a Visual Studio command prompt, or similar.
On Linux and Mac, the default compiler is clang++, a recent version is expected to be found in PATH. This can be overridden by setting CC, CXX, and AR.
There is a simple example in examples/simple_build directory that is a good place to get started with the minimal configuration.
To build and run the simple example with the default gcc compiler:
cd examples/simple_build ../../out/gn gen -C out ninja -C out ./out/hello
For a maximal configuration see the Chromium setup:
and the Fuchsia setup:
If you find a bug, you can see if it is known or report it in the bug database.
GN uses Gerrit for code review. The short version of how to patch is:
Register at https://gn-review.googlesource.com. ... edit code ... ninja -C out && out/gn_unittests
Then, to upload a change for review:
git commit git push origin HEAD:refs/for/master
The first time you do this you'll get an error from the server about a missing change-ID. Follow the directions in the error message to install the change-ID hook and run git commit --amend to apply the hook to the current commit.
When revising a change, use:
git commit --amend git push origin HEAD:refs/for/master
which will add the new changes to the existing code review, rather than creating a new one.
We ask that all contributors sign Google's Contributor License Agreement (either individual or corporate as appropriate, select ‘any other Google project’).
You may ask questions and follow along with GN‘s development on Chromium’s gn-dev@ Google Group.