| commit | 24411bec62d0d848e466e5ab9d5e61dd6d9f88d4 | [log] [tgz] |
|---|---|---|
| author | Takuto Ikuta <tikuta@google.com> | Wed Mar 20 07:50:39 2019 +0900 |
| committer | Commit Bot <commit-bot@chromium.org> | Tue Mar 19 23:04:42 2019 +0000 |
| tree | 5eb069afe085b5856220a563195deeff7bcb2486 | |
| parent | 3941394b9943eb5c095e7d71febbe6764295ca77 [diff] |
Make gn check faster
This CL skip re-calculation of unreachable check by caching unreachable
result.
In chromium, unreachable targets are sometimes there if an included
header file is listed in sources of several targets.
e.g.
```
source_set("x") {
sources = [ "x.cc", "y.cc" ] # both x.cc and y.cc have #include "a.h"
deps = [ ":a" ]
}
source_set("a") {
sources = [ "a.h" ]
}
source_set("a2") {
sources = [ "a.h" ]
}
source_set("a3") {
sources = [ "a.h" ]
}
```
In above example, dependency checker tries to find dependency path from
"x" to "a", "a2" and "a3". If "a" is not checked first, checker does
unreachable check for "a2" or "a3". And checker does such unreachable
check for "a.h" found in both x.cc and y.cc.
That seems the main reason of duplicate check in chromium.
e.g. gfx_export.h listed in sources of multiple targets.
https://cs.chromium.org/search/?q=gfx_export.h+file:gn&sq=package:chromium&type=cs
With this CL, `gn gen --check` for chromium on Z840 Win10 improved from
53.2s to 24.5s
I hope this makes 'generate_build_files' step faster on win7-rel
builder.
e.g. tooks nearly 3mins in
https://ci.chromium.org/p/chromium/builders/try/win7-rel/42250
Bug: chromium:941946
Change-Id: I7b797c8739a899b3a8519a81a1b1629e5affa659
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/4240
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Brett Wilson <brettw@chromium.org>
GN is a meta-build system that generates build files for Ninja. There is documentation in docs/ and a presentation on it.
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.
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 cl upload --gerrit
When revising a change, use:
git commit --amend git cl upload --gerrit
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 w/ GN‘s development on Chromium’s gn-dev@ Google Group.