rust: Clean up target configs and test some more

See the new docs for details. The difference is vis-a-vis older versions
of this PR, not master.
This commit is contained in:
John Ericson 2020-11-28 19:32:43 +00:00
parent 8ddf5c6907
commit b7650aaa77
3 changed files with 47 additions and 33 deletions

View File

@ -71,14 +71,14 @@ By default, it takes the `stdenv.hostPlatform.config` and replaces components
where they are known to differ. But there are ways to customize the argument:
- To choose a different target by name, define
`stdenv.hostPlatform.rustc.arch.config` as that name (a string), and that
`stdenv.hostPlatform.rustc.config` as that name (a string), and that
name will be used instead.
For example:
```nix
import <nixpkgs> {
crossSystem = (import <nixpkgs/lib>).systems.examples.armhf-embedded // {
rustc.arch.config = "thumbv7em-none-eabi";
rustc.config = "thumbv7em-none-eabi";
};
}
```
@ -88,18 +88,18 @@ where they are known to differ. But there are ways to customize the argument:
```
- To pass a completely custom target, define
`stdenv.hostPlatform.rustc.arch.config` with its name, and
`stdenv.hostPlatform.rustc.arch.custom` with the value. The value will be
`stdenv.hostPlatform.rustc.config` with its name, and
`stdenv.hostPlatform.rustc.platform` with the value. The value will be
serialized to JSON in a file called
`${stdenv.hostPlatform.rustc.arch.config}.json`, and the path of that file
`${stdenv.hostPlatform.rustc.config}.json`, and the path of that file
will be used instead.
For example:
```nix
import <nixpkgs> {
crossSystem = (import <nixpkgs/lib>).systems.examples.armhf-embedded // {
rustc.arch.config = "thumb-crazy";
rustc.arch.custom = { foo = ""; bar = ""; };
rustc.config = "thumb-crazy";
rustc.platform = { foo = ""; bar = ""; };
};
}
will result in:

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@ -27,7 +27,7 @@
# Returns the name of the rust target, even if it is custom. Adjustments are
# because rust has slightly different naming conventions than we do.
toRustTarget = platform: with platform.parsed; let
cpu_ = platform.rustc.arch or {
cpu_ = platform.rustc.platform.arch or {
"armv7a" = "armv7";
"armv7l" = "armv7";
"armv6l" = "arm";
@ -38,8 +38,8 @@
# Returns the name of the rust target if it is standard, or the json file
# containing the custom target spec.
toRustTargetSpec = platform:
if (platform.rustc.arch or {}) ? custom
then builtins.toFile (platform.rustc.config + ".json") (builtins.toJSON platform.rustc.arch.custom)
if (platform.rustc or {}) ? platform
then builtins.toFile (toRustTarget platform + ".json") (builtins.toJSON platform.rustc.platform)
else toRustTarget platform;
# This just contains tools for now. But it would conceivably contain

View File

@ -1,6 +1,7 @@
{ lib, rustPlatform, fetchFromGitHub, writeText }:
{ lib, rust, rustPlatform, fetchFromGitHub }:
rustPlatform.buildRustPackage rec {
let
mkBlogOsTest = target: rustPlatform.buildRustPackage rec {
name = "blog_os-sysroot-test";
src = fetchFromGitHub {
@ -12,27 +13,7 @@ rustPlatform.buildRustPackage rec {
cargoSha256 = "1cbcplgz28yxshyrp2krp1jphbrcqdw6wxx3rry91p7hiqyibd30";
# The book uses rust-lld for linking, but rust-lld is not currently packaged for NixOS.
# The justification in the book for using rust-lld suggests that gcc can still be used for testing:
# > Instead of using the platform's default linker (which might not support Linux targets),
# > we use the cross platform LLD linker that is shipped with Rust for linking our kernel.
# https://github.com/phil-opp/blog_os/blame/7212ffaa8383122b1eb07fe1854814f99d2e1af4/blog/content/second-edition/posts/02-minimal-rust-kernel/index.md#L157
target = writeText "x86_64-blog_os.json" ''
{
"llvm-target": "x86_64-unknown-none",
"data-layout": "e-m:e-i64:64-f80:128-n8:16:32:64-S128",
"arch": "x86_64",
"target-endian": "little",
"target-pointer-width": "64",
"target-c-int-width": "32",
"os": "none",
"executables": true,
"linker-flavor": "gcc",
"panic-strategy": "abort",
"disable-redzone": true,
"features": "-mmx,-sse,+soft-float"
}
'';
inherit target;
RUSTFLAGS = "-C link-arg=-nostartfiles";
@ -42,5 +23,38 @@ rustPlatform.buildRustPackage rec {
meta = with lib; {
description = "Test for using custom sysroots with buildRustPackage";
maintainers = with maintainers; [ aaronjanse ];
platforms = lib.platforms.x86_64;
};
};
# The book uses rust-lld for linking, but rust-lld is not currently packaged for NixOS.
# The justification in the book for using rust-lld suggests that gcc can still be used for testing:
# > Instead of using the platform's default linker (which might not support Linux targets),
# > we use the cross platform LLD linker that is shipped with Rust for linking our kernel.
# https://github.com/phil-opp/blog_os/blame/7212ffaa8383122b1eb07fe1854814f99d2e1af4/blog/content/second-edition/posts/02-minimal-rust-kernel/index.md#L157
targetContents = {
"llvm-target" = "x86_64-unknown-none";
"data-layout" = "e-m:e-i64:64-f80:128-n8:16:32:64-S128";
"arch" = "x86_64";
"target-endian" = "little";
"target-pointer-width" = "64";
"target-c-int-width" = "32";
"os" = "none";
"executables" = true;
"linker-flavor" = "gcc";
"panic-strategy" = "abort";
"disable-redzone" = true;
"features" = "-mmx,-sse,+soft-float";
};
in {
blogOS-targetByFile = mkBlogOsTest (builtins.toFile "x86_64-blog_os.json" (builtins.toJSON targetContents));
blogOS-targetByNix = let
plat = lib.systems.elaborate { config = "x86_64-none"; } // {
rustc = {
config = "x86_64-blog_os";
platform = targetContents;
};
};
in mkBlogOsTest (rust.toRustTargetSpec plat);
}