Add GNU/Hurd target

The actual support will follow once the stage0 compiler has caught up with
this definition.

Author: sthibaul

compiler/rustc_target/src/spec/hurd_base.rs

@@ -0,0 +1,15 @@
+use crate::spec::{cvs, RelroLevel, TargetOptions};
+
+pub fn opts() -> TargetOptions {
+    TargetOptions {
+        os: "hurd".into(),
+        dynamic_linking: true,
+        families: cvs!["unix"],
+        has_rpath: true,
+        position_independent_executables: true,
+        relro_level: RelroLevel::Full,
+        has_thread_local: true,
+        crt_static_respected: true,
+        ..Default::default()
+    }
+}

compiler/rustc_target/src/spec/hurd_gnu_base.rs

@@ -0,0 +1,5 @@
+use crate::spec::TargetOptions;
+
+pub fn opts() -> TargetOptions {
+    TargetOptions { env: "gnu".into(), ..super::hurd_base::opts() }
+}

compiler/rustc_target/src/spec/i686_unknown_hurd_gnu.rs

@@ -0,0 +1,19 @@
+use crate::spec::{Cc, LinkerFlavor, Lld, StackProbeType, Target};
+
+pub fn target() -> Target {
+    let mut base = super::hurd_gnu_base::opts();
+    base.cpu = "pentiumpro".into();
+    base.max_atomic_width = Some(64);
+    base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m32"]);
+    base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };
+
+    Target {
+        llvm_target: "i686-unknown-hurd-gnu".into(),
+        pointer_width: 32,
+        data_layout: "e-m:e-p:32:32-p270:32:32-p271:32:32-p272:64:64-\
+            f64:32:64-f80:32-n8:16:32-S128"
+            .into(),
+        arch: "x86".into(),
+        options: base,
+    }
+}

compiler/rustc_target/src/spec/mod.rs

@@ -71,6 +71,8 @@ mod freebsd_base;
 mod fuchsia_base;
 mod haiku_base;
 mod hermit_base;
+mod hurd_base;
+mod hurd_gnu_base;
 mod illumos_base;
 mod l4re_base;
 mod linux_base;
@@ -1367,6 +1369,8 @@ supported_targets! {
     ("i686-unknown-haiku", i686_unknown_haiku),
     ("x86_64-unknown-haiku", x86_64_unknown_haiku),
 
+    ("i686-unknown-hurd-gnu", i686_unknown_hurd_gnu),
+
     ("aarch64-apple-darwin", aarch64_apple_darwin),
     ("x86_64-apple-darwin", x86_64_apple_darwin),
     ("x86_64h-apple-darwin", x86_64h_apple_darwin),

src/bootstrap/lib.rs

@@ -133,7 +133,8 @@ const EXTRA_CHECK_CFGS: &[(Option<Mode>, &'static str, Option<&[&'static str]>)]
     // #[cfg(bootstrap)]
     (Some(Mode::Std), "target_vendor", Some(&["unikraft"])),
     (Some(Mode::Std), "target_env", Some(&["libnx"])),
-    (Some(Mode::Std), "target_os", Some(&["teeos"])),
+    // #[cfg(bootstrap)] hurd
+    (Some(Mode::Std), "target_os", Some(&["teeos", "hurd"])),
     // #[cfg(bootstrap)] mips32r6, mips64r6
     (
         Some(Mode::Std),

src/doc/rustc/src/SUMMARY.md

@@ -28,6 +28,7 @@
     - [armv7-unknown-linux-uclibceabihf](platform-support/armv7-unknown-linux-uclibceabihf.md)
     - [\*-android and \*-androideabi](platform-support/android.md)
     - [\*-linux-ohos](platform-support/openharmony.md)
+    - [\*-hurd-gnu](platform-support/hurd.md)
     - [aarch64-unknown-teeos](platform-support/aarch64-unknown-teeos.md)
     - [\*-esp-espidf](platform-support/esp-idf.md)
     - [\*-unknown-fuchsia](platform-support/fuchsia.md)

src/doc/rustc/src/platform-support.md

@@ -268,6 +268,7 @@ target | std | host | notes
 `i686-apple-darwin` | ✓ | ✓ | 32-bit macOS (10.7+, Lion+)
 `i686-pc-windows-msvc` | * |  | 32-bit Windows XP support
 `i686-unknown-haiku` | ✓ | ✓ | 32-bit Haiku
+[`i686-unknown-hurd-gnu`](platform-support/hurd.md) | ✓ | ✓ | 32-bit GNU/Hurd
 [`i686-unknown-netbsd`](platform-support/netbsd.md) | ✓ | ✓ | NetBSD/i386 with SSE2
 [`i686-unknown-openbsd`](platform-support/openbsd.md) | ✓ | ✓ | 32-bit OpenBSD
 `i686-uwp-windows-gnu` | ? |  |

src/doc/rustc/src/platform-support/hurd.md

@@ -0,0 +1,35 @@
+# `i686-unknown-hurd-gnu`
+
+**Tier: 3**
+
+[GNU/Hurd] is the GNU Hurd is the GNU project's replacement for the Unix kernel.
+
+## Target maintainers
+
+- Samuel Thibault, `[email protected]`, https://github.com/sthibaul/
+
+## Requirements
+
+The target supports host tools.
+
+The GNU/Hurd target supports `std` and uses the standard ELF file format.
+
+## Building the target
+
+This target can be built by adding `i686-unknown-hurd-gnu` as target in the rustc list.
+
+## Building Rust programs
+
+Rust does not yet ship pre-compiled artifacts for this target. To compile for
+this target, you will either need to build Rust with the target enabled (see
+"Building the target" above), or build your own copy of `core` by using
+`build-std` or similar.
+
+## Testing
+
+Tests can be run in the same way as a regular binary.
+
+## Cross-compilation toolchains and C code
+
+The target supports C code, the GNU toolchain calls the target
+`i686-unknown-gnu`.

tests/ui/check-cfg/values-target-json.stderr

@@ -6,7 +6,7 @@ LL | #[cfg(target_os = "linuz")]
    |                   |
    |                   help: there is a expected value with a similar name: `"linux"`
    |
-   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `ericos`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `openbsd`, `psp`, `redox`, `solaris`, `solid_asp3`, `teeos`, `tvos`, `uefi`, `unknown`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`
+   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `ericos`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `openbsd`, `psp`, `redox`, `solaris`, `solid_asp3`, `teeos`, `tvos`, `uefi`, `unknown`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`
    = note: `#[warn(unexpected_cfgs)]` on by default
 
 warning: 1 warning emitted

tests/ui/check-cfg/well-known-values.stderr

@@ -6,7 +6,7 @@ LL | #[cfg(target_os = "linuz")]
    |                   |
    |                   help: there is a expected value with a similar name: `"linux"`
    |
-   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `openbsd`, `psp`, `redox`, `solaris`, `solid_asp3`, `teeos`, `tvos`, `uefi`, `unknown`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`
+   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `openbsd`, `psp`, `redox`, `solaris`, `solid_asp3`, `teeos`, `tvos`, `uefi`, `unknown`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`
    = note: `#[warn(unexpected_cfgs)]` on by default
 
 warning: unexpected `cfg` condition value