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| -rw-r--r-- | configure.ac | 8 | ||||
| -rw-r--r-- | doc/manual/src/contributing/hacking.md | 63 |
2 files changed, 51 insertions, 20 deletions
diff --git a/configure.ac b/configure.ac index cc7009859..6d78237f0 100644 --- a/configure.ac +++ b/configure.ac @@ -7,12 +7,12 @@ AC_PROG_SED # Construct a Nix system name (like "i686-linux"): # https://www.gnu.org/software/autoconf/manual/html_node/Canonicalizing.html#index-AC_005fCANONICAL_005fHOST-1 -# The inital value is produced by the `config.guess` script: -# https://git.savannah.gnu.org/cgit/config.git/tree/config.guess +# The inital value is produced by the `config/config.guess` script: +# upstream: https://git.savannah.gnu.org/cgit/config.git/tree/config.guess # It has the following form, which is not documented anywhere: # <cpu>-<vendor>-<os>[<version>][-<abi>] -# If `./configure` is passed any of the `--host`, `--build`, `--target` options, the value comes from `config.sub` instead: -# https://git.savannah.gnu.org/cgit/config.git/tree/config.sub +# If `./configure` is passed any of the `--host`, `--build`, `--target` options, the value comes from `config/config.sub` instead: +# upstream: https://git.savannah.gnu.org/cgit/config.git/tree/config.sub AC_CANONICAL_HOST AC_MSG_CHECKING([for the canonical Nix system name]) diff --git a/doc/manual/src/contributing/hacking.md b/doc/manual/src/contributing/hacking.md index 7b2440971..c7cb0d980 100644 --- a/doc/manual/src/contributing/hacking.md +++ b/doc/manual/src/contributing/hacking.md @@ -110,41 +110,72 @@ You can also build Nix for one of the [supported platforms](#platforms). ## Platforms -As specified in [`flake.nix`], Nix can be built for various platforms: - -- `aarch64-linux` -- `i686-linux` -- `x86_64-darwin` -- `x86_64-linux` +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` + In order to build Nix for a different platform than the one you're currently -on, you need to have some way for your system Nix to build code for that -platform. Common solutions include [remote builders] and [binfmt emulation] +on, you need a way for your current Nix installation to build code for that +platform. Common solutions include [remote builders] and [binary format emulation] (only supported on NixOS). [remote builders]: ../advanced-topics/distributed-builds.md [binfmt emulation]: https://nixos.org/manual/nixos/stable/options.html#opt-boot.binfmt.emulatedSystems -These solutions let Nix perform builds as if you're on the native platform, so -executing the build is as simple as +Given such a setup, executing the build only requires selecting the respective output attribute. +For example, to compile for `aarch64-linux`: ```console -$ nix build .#packages.aarch64-linux.default +$ nix-build --attr packages.aarch64-linux.default ``` -for flake-enabled Nix, or +or for Nix with the [`flakes`] and [`nix-command`] experimental features enabled: ```console -$ nix-build --attr packages.aarch64-linux.default +$ nix build .#packages.aarch64-linux.default ``` -for classic Nix. +Cross-compiled builds are available for ARMv6 (`armv6l-linux`) and ARMv7 (`armv7l-linux`). +Add more [system types](#system-type) to `crossSystems` in `flake.nix` to bootstrap Nix on unsupported platforms. + +## System type + +Nix uses a string with he 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> +``` -You can use any of the other supported platforms in place of `aarch64-linux`. +For historic reasons and backward-compatibility, some CPU and OS identifiers are transformed as follows in [`configure.ac`](https://github.com/nixos/nix/blob/master/config/config.sub): -Cross-compiled builds are available for ARMv6 and ARMv7, and Nix on unsupported platforms can be bootstrapped by adding more `crossSystems` in `flake.nix`. +| `config.guess` | Nix | +|----------------------------|---------------------| +| `amd64` | `x86_64` | +| `i*86` | `i686` | +| `arm6` | `arm6l` | +| `arm7` | `arm7l` | +| `linux-gnu*` | `linux` | +| `linux-musl*` | `linux` | ## Compilation environments |