|author||RJ Ascani <firstname.lastname@example.org>||Mon Aug 24 18:52:23 2020 -0700|
|committer||Commit Bot <email@example.com>||Mon Sep 28 20:06:45 2020 +0000|
Switch source_set stamp targets to phony targets GN uses stamp files for a variety of output types as a mechanism for completing a group of dependencies. Ninja's phony targets can be used in the same manner. Semantically, stamp and phony only differ in one way: if a phony target has no dependencies, then it is treated as always dirty and is run every time. The source_set output type always generates a stamp file in the target ninja file. This CL replaces the source_set's stamp target with a phony target. In the case where the source_set's new phony target does not have any inputs, no targets will depend on it. An example of where that might happen is a header only source_set. There are no object files to generate, but targets that depend on the header only source_set will generate dependencies on those headers through depfiles. Bug: 187 Change-Id: I159f2f39a988eea189e4df9f5d9207fda6db5c58 Reviewed-on: https://gn-review.googlesource.com/c/gn/+/9820 Reviewed-by: Brett Wilson <firstname.lastname@example.org> Commit-Queue: Brett Wilson <email@example.com>
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.