mirror of
https://github.com/privatevoid-net/nix-super.git
synced 2024-11-15 18:56:16 +02:00
eb7d7780b1
This is needed to avoid this https://github.com/mesonbuild/meson/issues/13774 when we go back to making our subproject directory `src`.
293 lines
9.4 KiB
Markdown
293 lines
9.4 KiB
Markdown
# Building Nix
|
|
|
|
This section provides some notes on how to start hacking on Nix.
|
|
To get the latest version of Nix from GitHub:
|
|
|
|
```console
|
|
$ git clone https://github.com/NixOS/nix.git
|
|
$ cd nix
|
|
```
|
|
|
|
> **Note**
|
|
>
|
|
> The following instructions assume you already have some version of Nix installed locally, so that you can use it to set up the development environment.
|
|
> If you don't have it installed, follow the [installation instructions](../installation/index.md).
|
|
|
|
|
|
To build all dependencies and start a shell in which all environment variables are set up so that those dependencies can be found:
|
|
|
|
```console
|
|
$ nix-shell
|
|
```
|
|
|
|
To get a shell with one of the other [supported compilation environments](#compilation-environments):
|
|
|
|
```console
|
|
$ nix-shell --attr devShells.x86_64-linux.native-clangStdenvPackages
|
|
```
|
|
|
|
> **Note**
|
|
>
|
|
> You can use `native-ccacheStdenvPackages` to drastically improve rebuild time.
|
|
> By default, [ccache](https://ccache.dev) keeps artifacts in `~/.cache/ccache/`.
|
|
|
|
To build Nix itself in this shell:
|
|
|
|
```console
|
|
[nix-shell]$ mesonFlags+=" --prefix=$(pwd)/outputs/out"
|
|
[nix-shell]$ dontAddPrefix=1 mesonConfigurePhase
|
|
[nix-shell]$ ninjaBuildPhase
|
|
```
|
|
|
|
To test it:
|
|
|
|
```console
|
|
[nix-shell]$ mesonCheckPhase
|
|
```
|
|
|
|
To install it in `$(pwd)/outputs`:
|
|
|
|
```console
|
|
[nix-shell]$ ninjaInstallPhase
|
|
[nix-shell]$ ./outputs/out/bin/nix --version
|
|
nix (Nix) 2.12
|
|
```
|
|
|
|
To build a release version of Nix for the current operating system and CPU architecture:
|
|
|
|
```console
|
|
$ nix-build
|
|
```
|
|
|
|
You can also build Nix for one of the [supported platforms](#platforms).
|
|
|
|
## Building Nix with flakes
|
|
|
|
This section assumes you are using Nix with the [`flakes`] and [`nix-command`] experimental features enabled.
|
|
|
|
[`flakes`]: @docroot@/development/experimental-features.md#xp-feature-flakes
|
|
[`nix-command`]: @docroot@/development/experimental-features.md#xp-nix-command
|
|
|
|
To build all dependencies and start a shell in which all environment variables are set up so that those dependencies can be found:
|
|
|
|
```console
|
|
$ nix develop
|
|
```
|
|
|
|
This shell also adds `./outputs/bin/nix` to your `$PATH` so you can run `nix` immediately after building it.
|
|
|
|
To get a shell with one of the other [supported compilation environments](#compilation-environments):
|
|
|
|
```console
|
|
$ nix develop .#native-clangStdenvPackages
|
|
```
|
|
|
|
> **Note**
|
|
>
|
|
> Use `ccacheStdenv` to drastically improve rebuild time.
|
|
> By default, [ccache](https://ccache.dev) keeps artifacts in `~/.cache/ccache/`.
|
|
|
|
To build Nix itself in this shell:
|
|
|
|
```console
|
|
[nix-shell]$ mesonConfigurePhase
|
|
[nix-shell]$ ninjaBuildPhase
|
|
```
|
|
|
|
To test it:
|
|
|
|
```console
|
|
[nix-shell]$ mesonCheckPhase
|
|
```
|
|
|
|
To install it in `$(pwd)/outputs`:
|
|
|
|
```console
|
|
[nix-shell]$ ninjaInstallPhase
|
|
[nix-shell]$ nix --version
|
|
nix (Nix) 2.12
|
|
```
|
|
|
|
For more information on running and filtering tests, see
|
|
[`testing.md`](./testing.md).
|
|
|
|
To build a release version of Nix for the current operating system and CPU architecture:
|
|
|
|
```console
|
|
$ nix build
|
|
```
|
|
|
|
You can also build Nix for one of the [supported platforms](#platforms).
|
|
|
|
## Platforms
|
|
|
|
Nix can be built for various platforms, as specified in [`flake.nix`]:
|
|
|
|
[`flake.nix`]: https://github.com/nixos/nix/blob/master/flake.nix
|
|
|
|
- `x86_64-linux`
|
|
- `x86_64-darwin`
|
|
- `i686-linux`
|
|
- `aarch64-linux`
|
|
- `aarch64-darwin`
|
|
- `armv6l-linux`
|
|
- `armv7l-linux`
|
|
- `riscv64-linux`
|
|
|
|
In order to build Nix for a different platform than the one you're currently
|
|
on, you need a way for your current Nix installation to build code for that
|
|
platform. Common solutions include [remote build machines] and [binary format emulation]
|
|
(only supported on NixOS).
|
|
|
|
[remote builders]: @docroot@/language/derivations.md#attr-builder
|
|
[binary format emulation]: https://nixos.org/manual/nixos/stable/options.html#opt-boot.binfmt.emulatedSystems
|
|
|
|
Given such a setup, executing the build only requires selecting the respective attribute.
|
|
For example, to compile for `aarch64-linux`:
|
|
|
|
```console
|
|
$ nix-build --attr packages.aarch64-linux.default
|
|
```
|
|
|
|
or for Nix with the [`flakes`] and [`nix-command`] experimental features enabled:
|
|
|
|
```console
|
|
$ nix build .#packages.aarch64-linux.default
|
|
```
|
|
|
|
Cross-compiled builds are available for:
|
|
- `armv6l-linux`
|
|
- `armv7l-linux`
|
|
- `riscv64-linux`
|
|
Add more [system types](#system-type) to `crossSystems` in `flake.nix` to bootstrap Nix on unsupported platforms.
|
|
|
|
### Building for multiple platforms at once
|
|
|
|
It is useful to perform multiple cross and native builds on the same source tree,
|
|
for example to ensure that better support for one platform doesn't break the build for another.
|
|
Meson thankfully makes this very easy by confining all build products to the build directory --- one simple shares the source directory between multiple build directories, each of which contains the build for Nix to a different platform.
|
|
|
|
Nixpkgs's `mesonConfigurePhase` always chooses `build` in the current directory as the name and location of the build.
|
|
This makes having multiple build directories slightly more inconvenient.
|
|
The good news is that Meson/Ninja seem to cope well with relocating the build directory after it is created.
|
|
|
|
Here's how to do that
|
|
|
|
1. Configure as usual
|
|
|
|
```bash
|
|
mesonConfigurePhase
|
|
```
|
|
|
|
2. Rename the build directory
|
|
|
|
```bash
|
|
cd .. # since `mesonConfigurePhase` cd'd inside
|
|
mv build build-linux # or whatever name we want
|
|
cd build-linux
|
|
```
|
|
|
|
3. Build as usual
|
|
|
|
```bash
|
|
ninjaBuildPhase
|
|
```
|
|
|
|
> **N.B.**
|
|
> [`nixpkgs#335818`](https://github.com/NixOS/nixpkgs/issues/335818) tracks giving `mesonConfigurePhase` proper support for custom build directories.
|
|
> When it is fixed, we can simplify these instructions and then remove this notice.
|
|
|
|
## System type
|
|
|
|
Nix uses a string with the following format to identify the *system type* or *platform* it runs on:
|
|
|
|
```
|
|
<cpu>-<os>[-<abi>]
|
|
```
|
|
|
|
It is set when Nix is compiled for the given system, and based on the output of [`config.guess`](https://github.com/nixos/nix/blob/master/config/config.guess) ([upstream](https://git.savannah.gnu.org/cgit/config.git/tree/config.guess)):
|
|
|
|
```
|
|
<cpu>-<vendor>-<os>[<version>][-<abi>]
|
|
```
|
|
|
|
When Nix is built such that `./configure` is passed any of the `--host`, `--build`, `--target` options, the value is based on the output of [`config.sub`](https://github.com/nixos/nix/blob/master/config/config.sub) ([upstream](https://git.savannah.gnu.org/cgit/config.git/tree/config.sub)):
|
|
|
|
```
|
|
<cpu>-<vendor>[-<kernel>]-<os>
|
|
```
|
|
|
|
For historic reasons and backward-compatibility, some CPU and OS identifiers are translated from the GNU Autotools naming convention in [`configure.ac`](https://github.com/nixos/nix/blob/master/configure.ac) as follows:
|
|
|
|
| `config.guess` | Nix |
|
|
|----------------------------|---------------------|
|
|
| `amd64` | `x86_64` |
|
|
| `i*86` | `i686` |
|
|
| `arm6` | `arm6l` |
|
|
| `arm7` | `arm7l` |
|
|
| `linux-gnu*` | `linux` |
|
|
| `linux-musl*` | `linux` |
|
|
|
|
## Compilation environments
|
|
|
|
Nix can be compiled using multiple environments:
|
|
|
|
- `stdenv`: default;
|
|
- `gccStdenv`: force the use of `gcc` compiler;
|
|
- `clangStdenv`: force the use of `clang` compiler;
|
|
- `ccacheStdenv`: enable [ccache], a compiler cache to speed up compilation.
|
|
|
|
To build with one of those environments, you can use
|
|
|
|
```console
|
|
$ nix build .#nix-ccacheStdenv
|
|
```
|
|
|
|
for flake-enabled Nix, or
|
|
|
|
```console
|
|
$ nix-build --attr nix-ccacheStdenv
|
|
```
|
|
|
|
for classic Nix.
|
|
|
|
You can use any of the other supported environments in place of `nix-ccacheStdenv`.
|
|
|
|
## Editor integration
|
|
|
|
The `clangd` LSP server is installed by default on the `clang`-based `devShell`s.
|
|
See [supported compilation environments](#compilation-environments) and instructions how to set up a shell [with flakes](#nix-with-flakes) or in [classic Nix](#classic-nix).
|
|
|
|
To use the LSP with your editor, you will want a `compile_commands.json` file telling `clangd` how we are compiling the code.
|
|
Meson's configure always produces this inside the build directory.
|
|
|
|
Configure your editor to use the `clangd` from the `.#native-clangStdenvPackages` shell. You can do that either by running it inside the development shell, or by using [nix-direnv](https://github.com/nix-community/nix-direnv) and [the appropriate editor plugin](https://github.com/direnv/direnv/wiki#editor-integration).
|
|
|
|
> **Note**
|
|
>
|
|
> For some editors (e.g. Visual Studio Code), you may need to install a [special extension](https://open-vsx.org/extension/llvm-vs-code-extensions/vscode-clangd) for the editor to interact with `clangd`.
|
|
> Some other editors (e.g. Emacs, Vim) need a plugin to support LSP servers in general (e.g. [lsp-mode](https://github.com/emacs-lsp/lsp-mode) for Emacs and [vim-lsp](https://github.com/prabirshrestha/vim-lsp) for vim).
|
|
> Editor-specific setup is typically opinionated, so we will not cover it here in more detail.
|
|
|
|
## Formatting and pre-commit hooks
|
|
|
|
You may run the formatters as a one-off using:
|
|
|
|
```console
|
|
./maintainers/format.sh
|
|
```
|
|
|
|
If you'd like to run the formatters before every commit, install the hooks:
|
|
|
|
```
|
|
pre-commit-hooks-install
|
|
```
|
|
|
|
This installs [pre-commit](https://pre-commit.com) using [cachix/git-hooks.nix](https://github.com/cachix/git-hooks.nix).
|
|
|
|
When making a commit, pay attention to the console output.
|
|
If it fails, run `git add --patch` to approve the suggestions _and commit again_.
|
|
|
|
To refresh pre-commit hook's config file, do the following:
|
|
1. Exit the development shell and start it again by running `nix develop`.
|
|
2. If you also use the pre-commit hook, also run `pre-commit-hooks-install` again.
|