Add minimal x86_64-lynx-lynxos178 support.

compiler/rustc_target/src/spec/base/lynxos178.rs

@@ -0,0 +1,31 @@
+use std::borrow::Cow;
+
+use crate::spec::{
+    PanicStrategy, RelocModel, RelroLevel, SplitDebuginfo, StackProbeType, TargetOptions, cvs,
+};
+
+pub(crate) fn opts() -> TargetOptions {
+    TargetOptions {
+        os: "lynxos178".into(),
+        dynamic_linking: false,
+        families: cvs!["unix"],
+        position_independent_executables: false,
+        static_position_independent_executables: false,
+        relro_level: RelroLevel::Full,
+        has_thread_local: false,
+        crt_static_respected: true,
+        panic_strategy: PanicStrategy::Abort,
+        linker: Some(Cow::Borrowed("x86_64-lynx-lynxos178-gcc")),
+        no_default_libraries: false,
+        eh_frame_header: false, // GNU ld (GNU Binutils) 2.37.50 does not support --eh-frame-hdr
+        max_atomic_width: Some(64),
+        supported_split_debuginfo: Cow::Borrowed(&[
+            SplitDebuginfo::Packed,
+            SplitDebuginfo::Unpacked,
+            SplitDebuginfo::Off,
+        ]),
+        relocation_model: RelocModel::Static,
+        stack_probes: StackProbeType::Inline,
+        ..Default::default()
+    }
+}

compiler/rustc_target/src/spec/base/mod.rs

@@ -19,6 +19,7 @@ pub(crate) mod linux_musl;
 pub(crate) mod linux_ohos;
 pub(crate) mod linux_uclibc;
 pub(crate) mod linux_wasm;
+pub(crate) mod lynxos178;
 pub(crate) mod msvc;
 pub(crate) mod netbsd;
 pub(crate) mod nto_qnx;

compiler/rustc_target/src/spec/mod.rs

@@ -2077,6 +2077,7 @@ supported_targets! {
     ("riscv32imafc-unknown-nuttx-elf", riscv32imafc_unknown_nuttx_elf),
     ("riscv64imac-unknown-nuttx-elf", riscv64imac_unknown_nuttx_elf),
     ("riscv64gc-unknown-nuttx-elf", riscv64gc_unknown_nuttx_elf),
+    ("x86_64-lynx-lynxos178", x86_64_lynx_lynxos178),
 
     ("x86_64-pc-cygwin", x86_64_pc_cygwin),
 }

compiler/rustc_target/src/spec/targets/x86_64_lynx_lynxos178.rs

@@ -0,0 +1,34 @@
+use crate::spec::{SanitizerSet, StackProbeType, Target, base};
+
+pub(crate) fn target() -> Target {
+    let mut base = base::lynxos178::opts();
+    base.cpu = "x86-64".into();
+    base.plt_by_default = false;
+    base.max_atomic_width = Some(64);
+    base.stack_probes = StackProbeType::Inline;
+    base.static_position_independent_executables = false;
+    base.supported_sanitizers = SanitizerSet::ADDRESS
+        | SanitizerSet::CFI
+        | SanitizerSet::KCFI
+        | SanitizerSet::DATAFLOW
+        | SanitizerSet::LEAK
+        | SanitizerSet::MEMORY
+        | SanitizerSet::SAFESTACK
+        | SanitizerSet::THREAD;
+    base.supports_xray = true;
+
+    Target {
+        llvm_target: "x86_64-unknown-unknown-gnu".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: Some("LynxOS-178".into()),
+            tier: Some(3),
+            host_tools: Some(false),
+            std: Some(false),
+        },
+        pointer_width: 64,
+        data_layout:
+            "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128".into(),
+        arch: "x86_64".into(),
+        options: base,
+    }
+}

src/bootstrap/src/core/sanity.rs

@@ -35,6 +35,7 @@ pub struct Finder {
 const STAGE0_MISSING_TARGETS: &[&str] = &[
     // just a dummy comment so the list doesn't get onelined
     "wasm32-wali-linux-musl",
+    "x86_64-lynx-lynxos178",
 ];
 
 /// Minimum version threshold for libstdc++ required when using prebuilt LLVM

src/doc/rustc/src/SUMMARY.md

@@ -61,6 +61,7 @@
     - [illumos](platform-support/illumos.md)
     - [loongarch\*-unknown-linux-\*](platform-support/loongarch-linux.md)
     - [loongarch\*-unknown-none\*](platform-support/loongarch-none.md)
+    - [\*-lynxos178-\*](platform-support/lynxos178.md)
     - [m68k-unknown-linux-gnu](platform-support/m68k-unknown-linux-gnu.md)
     - [m68k-unknown-none-elf](platform-support/m68k-unknown-none-elf.md)
     - [mips64-openwrt-linux-musl](platform-support/mips64-openwrt-linux-musl.md)

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

@@ -407,6 +407,7 @@ target | std | host | notes
 [`wasm32-wali-linux-musl`](platform-support/wasm32-wali-linux.md) | ? |  | WebAssembly with [WALI](https://github.com/arjunr2/WALI)
 [`x86_64-apple-tvos`](platform-support/apple-tvos.md) | ✓ |  | x86 64-bit tvOS
 [`x86_64-apple-watchos-sim`](platform-support/apple-watchos.md) | ✓ |  | x86 64-bit Apple WatchOS simulator
+[`x86_64-lynx-lynxos178`](platform-support/lynxos178.md) |   |  | x86_64 LynxOS-178
 [`x86_64-pc-cygwin`](platform-support/x86_64-pc-cygwin.md) | ✓ |  | 64-bit x86 Cygwin |
 [`x86_64-pc-nto-qnx710`](platform-support/nto-qnx.md) | ✓ |  | x86 64-bit QNX Neutrino 7.1 RTOS with default network stack (io-pkt) |
 [`x86_64-pc-nto-qnx710_iosock`](platform-support/nto-qnx.md) | ✓ |  | x86 64-bit QNX Neutrino 7.1 RTOS with new network stack (io-sock) |

src/doc/rustc/src/platform-support/lynxos178.md

@@ -0,0 +1,77 @@
+# `*-lynxos178-*`
+
+**Tier: 3**
+
+Targets for the LynxOS-178 operating system.
+
+[LynxOS-178](https://www.lynx.com/products/lynxos-178-do-178c-certified-posix-rtos)
+is a commercial RTOS designed for safety-critical real-time systems.  It is
+developed by Lynx Software Technologies as part of the
+[MOSA.ic](https://www.lynx.com/solutions/safe-and-secure-operating-environment)
+product suite.
+
+Target triples available:
+- `x86_64-lynx-lynxos178`
+
+## Target maintainers
+
+- Tim Newsome, https://github.com/tnewsome-lynx
+
+## Requirements
+
+To build Rust programs for LynxOS-178, you must first have LYNX MOSA.ic
+installed on the build machine.
+
+This target supports only cross-compilation, from the same hosts supported by
+the Lynx CDK.
+
+Currently only `no_std` programs are supported. Work to support `std` is in
+progress.
+
+## Building the target
+
+You can build Rust with support for x86_64-lynx-lynxos178 by adding that
+to the `target` list in `config.toml`, and then running `./x build --target
+x86_64-lynx-lynxos178 compiler`.
+
+## Building Rust programs
+
+Rust does not yet ship pre-compiled artifacts for this target. To compile for
+this target, you will need to build Rust with the target enabled (see "Building
+the target" above).
+
+Before executing `cargo`, you must configure the environment to build LynxOS-178
+binaries by running `source setup.sh` from the los178 directory.
+
+If your program/crates contain procedural macros, Rust must be able to build
+binaries for the host as well. The host gcc is hidden by sourcing setup.sh.  To
+deal with this, add the following to your project's `.cargo/config.toml`:
+```toml
+[target.x86_64-unknown-linux-gnu]
+linker = "lynx-host-gcc"
+```
+(If necessary substitute your host target triple for x86_64-unknown-linux-gnu.)
+
+To point `cargo` at the correct rustc binary, set the RUSTC environment
+variable.
+
+The core library should be usable. You can try by building it as part of your
+project:
+```bash
+cargo +nightly build -Z build-std=core --target x86_64-lynx-lynxos178
+```
+
+## Testing
+
+Binaries built with rust can be provided to a LynxOS-178 instance on its file
+system, where they can be executed. Rust binaries tend to be large, so it may
+be necessary to strip them first.
+
+It is possible to run the Rust testsuite by providing a test runner that takes
+the test binary and executes it under LynxOS-178. Most (all?) tests won't run
+without std support though, which is not yet supported.
+
+## Cross-compilation toolchains and C code
+
+LYNX MOSA.ic comes with all the tools required to cross-compile C code for
+LynxOS-178.

tests/assembly/targets/targets-elf.rs

@@ -571,6 +571,9 @@
 //@ revisions: x86_64_linux_android
 //@ [x86_64_linux_android] compile-flags: --target x86_64-linux-android
 //@ [x86_64_linux_android] needs-llvm-components: x86
+//@ revisions: x86_64_lynx_lynxos178
+//@ [x86_64_lynx_lynxos178] compile-flags: --target x86_64-lynx-lynxos178
+//@ [x86_64_lynx_lynxos178] needs-llvm-components: x86
 //@ revisions: x86_64_pc_nto_qnx710
 //@ [x86_64_pc_nto_qnx710] compile-flags: --target x86_64-pc-nto-qnx710
 //@ [x86_64_pc_nto_qnx710] needs-llvm-components: x86

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

@@ -201,7 +201,7 @@ warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
 LL |     target_os = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_os` are: `aix`, `amdhsa`, `android`, `cuda`, `cygwin`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `nuttx`, `openbsd`, `psp`, `psx`, `redox`, `rtems`, `solaris`, `solid_asp3`, `teeos`, `trusty`, `tvos`, `uefi`, `unknown`, `visionos`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, and `zkvm`
+   = note: expected values for `target_os` are: `aix`, `amdhsa`, `android`, `cuda`, `cygwin`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `lynxos178`, `macos`, `netbsd`, `none`, `nto`, `nuttx`, `openbsd`, `psp`, `psx`, `redox`, `rtems`, `solaris`, `solid_asp3`, `teeos`, `trusty`, `tvos`, `uefi`, `unknown`, `visionos`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, and `zkvm`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
@@ -274,7 +274,7 @@ LL | #[cfg(target_os = "linuz")] // testing that we suggest `linux`
    |                   |
    |                   help: there is a expected value with a similar name: `"linux"`
    |
-   = note: expected values for `target_os` are: `aix`, `amdhsa`, `android`, `cuda`, `cygwin`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `nuttx`, `openbsd`, `psp`, `psx`, `redox`, `rtems`, `solaris`, `solid_asp3`, `teeos`, `trusty`, `tvos`, `uefi`, `unknown`, `visionos`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, and `zkvm`
+   = note: expected values for `target_os` are: `aix`, `amdhsa`, `android`, `cuda`, `cygwin`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `lynxos178`, `macos`, `netbsd`, `none`, `nto`, `nuttx`, `openbsd`, `psp`, `psx`, `redox`, `rtems`, `solaris`, `solid_asp3`, `teeos`, `trusty`, `tvos`, `uefi`, `unknown`, `visionos`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, and `zkvm`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: 28 warnings emitted