|author||Honglin Yu <email@example.com>||Sun Oct 11 00:15:15 2020 +1100|
|committer||Commit Bot <firstname.lastname@example.org>||Tue Oct 20 04:53:59 2020 +0000|
Add a command line to define/overwrite "root" in ".gn" The new command line option "--root-target" will tell GN where to find the initial BUILD.gn. This is equivalent to define the "root" variable in ".gn" as before. And after this CL if "root" is also defined in ".gn", this option will overwite the value defined in ".gn". This is to achieve, to some extend, the "partial configuration" ability. For example, if we only want to configure and build the targets in a subfolder of Chromium like "//third_party/icu". We only need to run ``` gn gen out/icu --root-target="//third_party/icu" ``` The motivation of this feature is to make sharing packages between Chrome and CrOS much easier. BUG=chromium:1133101 TEST=It can indeed only configure subfolder of chromium like TEST="third_party/icu" and "third_party/grpc". TEST=It can overwrite the "root" variable in ".gn" correctly. Change-Id: If0742b409a529f34f435c6498de57667fabe7fc1 Reviewed-on: https://gn-review.googlesource.com/c/gn/+/10140 Reviewed-by: Brett Wilson <email@example.com> Commit-Queue: Brett Wilson <firstname.lastname@example.org>
GN is a meta-build system that generates build files for Ninja.
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
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
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.