From 544cfc5ef151bca8d625fbccc581200a77b00bc0 Mon Sep 17 00:00:00 2001 From: Cheng Zhao Date: Mon, 12 Feb 2024 19:39:30 +0900 Subject: [PATCH] doc: document the GN build PR-URL: https://github.com/nodejs/node/pull/51676 Reviewed-By: Marco Ippolito Reviewed-By: Joyee Cheung Reviewed-By: Debadree Chatterjee Reviewed-By: Yagiz Nizipli Reviewed-By: Luigi Pinca --- doc/contributing/gn-build.md | 125 +++++++++++++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 doc/contributing/gn-build.md diff --git a/doc/contributing/gn-build.md b/doc/contributing/gn-build.md new file mode 100644 index 00000000000..0981472805a --- /dev/null +++ b/doc/contributing/gn-build.md @@ -0,0 +1,125 @@ +# GN Build + +Similar to GYP, GN is a build system designed for building Chromium. The +official builds of Node.js are built with GYP, but GN build files are also +provided as an unofficial alternative build system. + +The GN build files only support a subset of the Node.js build configurations. +It's not required for all pull requests to Node.js to support GN builds, and the +CI of Node.js does not currently test GN builds, though Node.js welcomes pull +requests that improve GN support or fix breakages introduced by other pull +requests. + +Currently the GN build is used by: + +1. Electron for building Node.js together with Chromium. +2. V8 for testing the integration of Node.js in CI. + +## Files for GN support + +Node.js contains following GN build files: + +* `node.gni` - Public GN arguments for configuring the build. +* `*/BUILD.gn` - This is the file where GN looks for build rules, in Node.js it + just includes the `unofficial.gni` file to avoid accidental modifications. +* `*/unofficial.gni` - The actual build rules for each component. + +## Build with GN + +Unlike GYP, the GN tool does not include any built-in rules for compiling a +project, which means projects building with GN must provide their own build +configurations for things like how to invoke a C++ compiler. Chromium related +projects like V8 and skia choose to reuse Chromium's build configurations, and +V8's Node.js integration testing repository +([node-ci](https://chromium.googlesource.com/v8/node-ci/)) can be reused for +building Node.js. + +### 1. Install `depot_tools` + +The `depot_tools` is a set of tools used by Chromium related projects for +checking out code and managing dependencies, and since this guide is reusing the +infra of V8, it needs to be installed and added to `PATH`: + +```bash +git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git +export PATH=/path/to/depot_tools:$PATH +``` + +You can also follow the [official tutorial of +`depot_tools`](https://commondatastorage.googleapis.com/chrome-infra-docs/flat/depot_tools/docs/html/depot_tools_tutorial.html). + +### 2. Check out code of Node.js + +To check out the latest main branch of Node.js for building, use the `fetch` +tool from `depot_tools`: + +```bash +mkdir node_gn +cd node_gn +fetch node +``` + +You can choose to save some time by omitting git history: + +```bash +fetch --no-history node +``` + +After syncing is done, you will get a directory structure like this: + +```console +node_gn/ +├── .gclient +├── .gclient_entries +├── ... +└── node + ├── DEPS + ├── ... + ├── build/ + ├── node/ + └── tools/ +``` + +The `node_gn` is a workspace directory, which only contains configurations and +caches of the `gclient` tool from `depot_tools`, and the repository is checked +out at `node_gn/node`. + +The `node_gn/node` directory is not a checkout of Node.js, it is actually +[node-ci](https://chromium.googlesource.com/v8/node-ci/), the repository used by +V8 for testing integration with Node.js. The source code of Node.js is checked +out at `node_gn/node/node`. + +### 3. Build + +GN only supports [`ninja`](https://ninja-build.org) for building, so to build +Node.js with GN, `ninja` build files should be generated first, and then +`ninja` can be invoked to do the building. + +The `node-ci` repository provides a script for calling GN: + +```bash +cd node # Enter `node_gn/node` which contains a node-ci checkout +./tools/gn-gen.py out/Release +``` + +which writes `ninja` build files into the `out/Release` directory under +`node_gn/node`. + +And then you can execute `ninja`: + +```bash +ninja -C out/Release node +``` + +After the build is completed, the compiled Node.js executable can be found in +`out/Release/node`. + +## Status of the GN build + +Currently the GN build of Node.js is not fully functioning. It builds for macOS +and Linux, while the Windows build is still a work in progress. And some tests +are still failing with the GN build. + +There are also efforts on making GN build work without using `depot_tools`, +which is tracked in the issue +[#51689](https://github.com/nodejs/node/issues/51689).