Add x86_64-unknown-linux-none target

compiler/rustc_target/src/spec/mod.rs

@@ -1774,6 +1774,9 @@ supported_targets! {
     ("aarch64-unknown-linux-ohos", aarch64_unknown_linux_ohos),
     ("armv7-unknown-linux-ohos", armv7_unknown_linux_ohos),
     ("x86_64-unknown-linux-ohos", x86_64_unknown_linux_ohos),
+
+    ("x86_64-unknown-linux-none", x86_64_unknown_linux_none),
+
 }
 
 /// Cow-Vec-Str: Cow<'static, [Cow<'static, str>]>

compiler/rustc_target/src/spec/targets/x86_64_unknown_linux_none.rs

@@ -0,0 +1,25 @@
+use crate::spec::{base, Cc, LinkerFlavor, Lld, StackProbeType, Target};
+
+pub fn target() -> Target {
+    let mut base = base::linux::opts();
+    base.cpu = "x86-64".into();
+    base.max_atomic_width = Some(64);
+    base.stack_probes = StackProbeType::Inline;
+    base.linker_flavor = LinkerFlavor::Gnu(Cc::No, Lld::Yes);
+    base.linker = Some("rust-lld".into());
+
+    Target {
+        llvm_target: "x86_64-unknown-linux-none".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: None,
+            tier: None,
+            host_tools: None,
+            std: None,
+        },
+        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/doc/rustc/src/SUMMARY.md

@@ -74,6 +74,7 @@
     - [wasm64-unknown-unknown](platform-support/wasm64-unknown-unknown.md)
     - [\*-win7-windows-msvc](platform-support/win7-windows-msvc.md)
     - [x86_64-fortanix-unknown-sgx](platform-support/x86_64-fortanix-unknown-sgx.md)
+    - [x86_64-unknown-linux-none.md](platform-support/x86_64-unknown-linux-none.md)
     - [x86_64-unknown-none](platform-support/x86_64-unknown-none.md)
     - [x86_64h-apple-darwin](platform-support/x86_64h-apple-darwin.md)
 - [Targets](targets/index.md)

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

@@ -382,5 +382,6 @@ target | std | host | notes
 [`x86_64-win7-windows-msvc`](platform-support/win7-windows-msvc.md) | ✓ |   | 64-bit Windows 7 support
 `x86_64-wrs-vxworks` | ? |  |
 [`x86_64h-apple-darwin`](platform-support/x86_64h-apple-darwin.md) | ✓ | ✓ | macOS with late-gen Intel (at least Haswell)
+[`x86_64-unknown-linux-none`](platform-support/x86_64-unknown-linux-none.md) | * |  | 64-bit Linux with no libc
 
 [runs on NVIDIA GPUs]: https://github.com/japaric-archived/nvptx#targets

src/doc/rustc/src/platform-support/x86_64-unknown-linux-none.md

@@ -0,0 +1,40 @@
+# `x86_64-unknown-linux-none`
+
+**Tier: 3**
+
+Freestanding x86-64 linux binary with no dependency on libc.
+
+## Target maintainers
+
+- [morr0ne](https://github.com/morr0ne/)
+
+## Requirements
+
+This target is cross compiled and can be built from any host.
+
+This target has no support for host tools, std and alloc.
+
+## Building the target
+
+The target can be built by enabling it for a `rustc` build:
+
+```toml
+[build]
+build-stage = 1
+target = ["x86_64-unknown-linux-none"]
+```
+
+## 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
+
+Created binaries will run on linux without any external requirements
+
+## Cross-compilation toolchains and C code
+
+Support for C code is currently untested

tests/assembly/targets/targets-elf.rs

@@ -555,6 +555,9 @@
 //@ revisions: x86_64_unknown_linux_ohos
 //@ [x86_64_unknown_linux_ohos] compile-flags: --target x86_64-unknown-linux-ohos
 //@ [x86_64_unknown_linux_ohos] needs-llvm-components: x86
+//@ revisions: x86_64_unknown_linux_none
+//@ [x86_64_unknown_linux_none] compile-flags: --target x86_64-unknown-linux-none
+//@ [x86_64_unknown_linux_none] needs-llvm-components: x86
 //@ revisions: x86_64_unknown_netbsd
 //@ [x86_64_unknown_netbsd] compile-flags: --target x86_64-unknown-netbsd
 //@ [x86_64_unknown_netbsd] needs-llvm-components: x86