Fix problems pointed out by building with clang-cl.

After https://gn-review.googlesource.com/c/gn/+/6442 it's fairly
easy to build with clang-cl (and goma!), so I gave it a try:

set CC=c:\src\goma\goma-win64\gomacc.exe c:\src\chrome\src\third_party\llvm-build\Release+Asserts\bin\clang-cl.exe
set CXX=c:\src\goma\goma-win64\gomacc.exe c:\src\chrome\src\third_party\llvm-build\Release+Asserts\bin\clang-cl.exe
set CFLAGS=-Wno-c++11-narrowing
set LD=c:\src\chrome\src\third_party\llvm-build\Release+Asserts\bin\lld-link.exe
python build\gen.py
ninja -C out -j100

clang-cl caught a few issues, so this fixes them:
- remove a few unused private fields
- remove a few needless std::move() calls that prevent optimizations
- fix a benign -Wformat warning with char16_t
- fix some struct/class mismatches
- make a test actually test what it intended to test
- remove a const on a value type that had no effect
- fix field initialization order warnings in Value ctors

No behavior change.

Bug: none
Change-Id: I816a0382f2ef4f3a42d7945db6db5ce74fa9d5eb
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/6480
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
14 files changed
tree: 4e690db98f59f01397d85c8a2f7d3e2cdec8cd72
  1. .clang-format
  2. .editorconfig
  3. .gitignore
  4. .style.yapf
  5. AUTHORS
  6. LICENSE
  7. OWNERS
  8. README.md
  9. build/
  10. docs/
  11. examples/
  12. infra/
  13. misc/
  14. src/
README.md

GN

GN is a meta-build system that generates build files for Ninja.

Related resources:

Getting a binary

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.

Examples

There is a simple example in examples/simple_build directory that is a good place to get started with the minimal configuration.

For a maximal configuration see the Chromium setup:

and the Fuchsia setup:

Reporting bugs

If you find a bug, you can see if it is known or report it in the bug database.

Sending patches

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’).

Community

You may ask questions and follow along with GN‘s development on Chromium’s gn-dev@ Google Group.