| commit | 484245b93ef5cfe49d7ebb5df7046d11b3d48234 | [log] [tgz] |
|---|---|---|
| author | Scott Graham <scottmg@chromium.org> | Tue Aug 11 10:58:50 2020 -0700 |
| committer | Commit Bot <commit-bot@chromium.org> | Fri Aug 21 19:48:33 2020 +0000 |
| tree | 799f65f50f3c8d3bcc0570641e2fbdd821f5f0e4 | |
| parent | b722d8baf1a5ca7f0f5d88081e8378f119396ca8 [diff] |
clang: Fixes to module support
1. -fmodules-embed-all-files is a cc1 flag, and should have been passed
to clang++ via -Xclang.
2. Don't require a .cc in the target to emit the module_deps variables
(this is to be able to compile a target that contains only a
.modulemap, e.g. the C++ std module).
3. Add {{module_deps_no_self}}, which is the same as {{module_deps}}
except that it excludes the flags to include the pcm for the current
target.
That is, for A depending on B, and both using modules, when building
for A, {{module_deps}} will reference both A.pcm and B.pcm, and so
can be used to build .cc files in A. By contrast,
{{module_deps_no_self}} for A will only reference B.pcm, and so can
be used to build A.pcm.
Bug: fuchsia:27276
Change-Id: I239d1c5cd4d5d167251801b1347b02e8d89caeee
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/9680
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>
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
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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.
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You may ask questions and follow along with GN‘s development on Chromium’s gn-dev@ Google Group.