compiler: Add x86_64-unknown-managarm-mlibc target

Co-authored-by: Matt Taylor <mstaveleytaylor@gmail.com>
Co-authored-by: Dennis Bonke <dennis@managarm.org>

Author: 3 people

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

@@ -0,0 +1,35 @@
+use crate::spec::{cvs, Cc, LinkArgs, LinkerFlavor, Lld, RelroLevel, TargetOptions};
+
+pub fn opts() -> TargetOptions {
+    let mut args = LinkArgs::new();
+    args.insert(
+        LinkerFlavor::Gnu(Cc::Yes, Lld::No),
+        vec![
+            // We want to be able to strip as much executable code as possible
+            // from the linker command line, and this flag indicates to the
+            // linker that it can avoid linking in dynamic libraries that don't
+            // actually satisfy any symbols up to that point (as with many other
+            // resolutions the linker does). This option only applies to all
+            // following libraries so we're sure to pass it as one of the first
+            // arguments.
+            "-Wl,--as-needed".to_string().into(),
+            // Always enable NX protection when it is available
+            "-Wl,-z,noexecstack".to_string().into(),
+        ],
+    );
+
+    TargetOptions {
+        os: "managarm".to_string().into(),
+        env: "mlibc".to_string().into(),
+        dynamic_linking: true,
+        executables: true,
+        families: cvs!["unix"],
+        has_rpath: true,
+        pre_link_args: args,
+        position_independent_executables: true,
+        relro_level: RelroLevel::Full,
+        has_thread_local: true,
+        crt_static_respected: true,
+        ..Default::default()
+    }
+}

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

@@ -17,6 +17,7 @@ pub(crate) mod linux_gnu;
 pub(crate) mod linux_musl;
 pub(crate) mod linux_ohos;
 pub(crate) mod linux_uclibc;
+pub(crate) mod managarm_mlibc;
 pub(crate) mod msvc;
 pub(crate) mod netbsd;
 pub(crate) mod nto_qnx;

compiler/rustc_target/src/spec/mod.rs

@@ -1539,6 +1539,8 @@ supported_targets! {
     ("aarch64-unknown-redox", aarch64_unknown_redox),
     ("x86_64-unknown-redox", x86_64_unknown_redox),
 
+    ("x86_64-unknown-managarm-mlibc", x86_64_unknown_managarm_mlibc),
+
     ("i386-apple-ios", i386_apple_ios),
     ("x86_64-apple-ios", x86_64_apple_ios),
     ("aarch64-apple-ios", aarch64_apple_ios),

compiler/rustc_target/src/spec/targets/x86_64_unknown_managarm_mlibc.rs

@@ -0,0 +1,24 @@
+use crate::spec::{base, Cc, LinkerFlavor, Lld, StackProbeType, Target, TargetMetadata};
+
+pub fn target() -> Target {
+    let mut base = base::managarm_mlibc::opts();
+    base.cpu = "x86-64".to_string().into();
+    base.max_atomic_width = Some(64);
+    base.pre_link_args
+        .get_mut(&LinkerFlavor::Gnu(Cc::Yes, Lld::No))
+        .unwrap()
+        .push("-m64".to_string().into());
+    // don't use probe-stack=inline-asm until rust-lang/rust#83139 is resolved.
+    base.stack_probes = StackProbeType::Call;
+
+    Target {
+        llvm_target: "x86_64-unknown-managarm-mlibc".to_string().into(),
+        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"
+            .to_string()
+            .into(),
+        arch: "x86_64".to_string().into(),
+        options: base,
+        metadata: TargetMetadata { std: Some(false), tier: Some(3), ..Default::default() },
+    }
+}

src/tools/build-manifest/src/main.rs

@@ -166,6 +166,7 @@ static TARGETS: &[&str] = &[
     "x86_64-unknown-linux-gnux32",
     "x86_64-unknown-linux-musl",
     "x86_64-unknown-linux-ohos",
+    "x86_64-unknown-managarm-mlibc",
     "x86_64-unknown-netbsd",
     "x86_64-unknown-none",
     "x86_64-unknown-redox",

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

@@ -136,7 +136,7 @@ warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
 LL |     target_env = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_env` are: ``, `gnu`, `msvc`, `musl`, `newlib`, `nto70`, `nto71`, `ohos`, `p2`, `psx`, `relibc`, `sgx`, `uclibc`
+   = note: expected values for `target_env` are: ``, `gnu`, `mlibc`, `msvc`, `musl`, `newlib`, `nto70`, `nto71`, `ohos`, `p2`, `psx`, `relibc`, `sgx`, `uclibc`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
@@ -190,7 +190,7 @@ warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
 LL |     target_os = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = 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`, `zkvm`
+   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `managarm`, `netbsd`, `none`, `nto`, `openbsd`, `psp`, `redox`, `solaris`, `solid_asp3`, `teeos`, `tvos`, `uefi`, `unknown`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, `zkvm`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
@@ -263,7 +263,7 @@ 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`, `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`, `zkvm`
+   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `managarm`, `netbsd`, `none`, `nto`, `openbsd`, `psp`, `redox`, `solaris`, `solid_asp3`, `teeos`, `tvos`, `uefi`, `unknown`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, `zkvm`
    = note: see <https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html> for more information about checking conditional configuration
 
 warning: 27 warnings emitted