Add new target armv7-unknown-linux-uclibceabihf

Co-authored-by: Jonah Petri <jonah@petri.us>

compiler/rustc_codegen_llvm/src/callee.rs

@@ -176,6 +176,7 @@ pub fn get_fn(cx: &CodegenCx<'ll, 'tcx>, instance: Instance<'tcx>) -> &'ll Value
             if cx.use_dll_storage_attrs
                 && tcx.is_dllimport_foreign_item(instance_def_id)
                 && tcx.sess.target.env != "gnu"
+                && tcx.sess.target.env != "uclibc"
             {
                 llvm::LLVMSetDLLStorageClass(llfn, llvm::DLLStorageClass::DllImport);
             }

compiler/rustc_middle/src/ty/layout.rs

@@ -3009,7 +3009,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
         };
 
         let target = &self.tcx.sess.target;
-        let target_env_gnu_like = matches!(&target.env[..], "gnu" | "musl");
+        let target_env_gnu_like = matches!(&target.env[..], "gnu" | "musl" | "uclibc");
         let win_x64_gnu = target.os == "windows" && target.arch == "x86_64" && target.env == "gnu";
         let linux_s390x_gnu_like =
             target.os == "linux" && target.arch == "s390x" && target_env_gnu_like;
@@ -3107,7 +3107,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
             if arg.layout.is_zst() {
                 // For some forsaken reason, x86_64-pc-windows-gnu
                 // doesn't ignore zero-sized struct arguments.
-                // The same is true for {s390x,sparc64,powerpc}-unknown-linux-{gnu,musl}.
+                // The same is true for {s390x,sparc64,powerpc}-unknown-linux-{gnu,musl,uclibc}.
                 if is_return
                     || rust_abi
                     || (!win_x64_gnu

compiler/rustc_target/src/spec/armv7_unknown_linux_uclibceabihf.rs

@@ -0,0 +1,23 @@
+use crate::spec::{Target, TargetOptions};
+
+// This target is for uclibc Linux on ARMv7 without NEON or
+// thumb-mode. See the thumbv7neon variant for enabling both.
+
+pub fn target() -> Target {
+    let base = super::linux_uclibc_base::opts();
+    Target {
+        llvm_target: "armv7-unknown-linux-gnueabihf".to_string(),
+        pointer_width: 32,
+        data_layout: "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64".to_string(),
+        arch: "arm".to_string(),
+
+        options: TargetOptions {
+            // Info about features at https://wiki.debian.org/ArmHardFloatPort
+            features: "+v7,+vfp3,-d32,+thumb2,-neon".to_string(),
+            cpu: "generic".to_string(),
+            max_atomic_width: Some(64),
+            mcount: "_mcount".to_string(),
+            ..base
+        },
+    }
+}

compiler/rustc_target/src/spec/mod.rs

@@ -952,6 +952,8 @@ supported_targets! {
     ("bpfel-unknown-none", bpfel_unknown_none),
 
     ("armv6k-nintendo-3ds", armv6k_nintendo_3ds),
+
+    ("armv7-unknown-linux-uclibceabihf", armv7_unknown_linux_uclibceabihf),
 }
 
 /// Warnings encountered when parsing the target `json`.

library/std/src/sys/unix/mod.rs

@@ -307,6 +307,9 @@ cfg_if::cfg_if! {
         #[link(name = "zircon")]
         #[link(name = "fdio")]
         extern "C" {}
+    } else if #[cfg(all(target_os = "linux", target_env = "uclibc"))] {
+        #[link(name = "dl")]
+        extern "C" {}
     }
 }
 

library/std/src/sys/unix/process/process_unix.rs

@@ -419,7 +419,7 @@ impl Command {
         }
 
         // Only glibc 2.24+ posix_spawn() supports returning ENOENT directly.
-        #[cfg(all(target_os = "linux", target_env = "gnu"))]
+        #[cfg(all(target_os = "linux", any(target_env = "gnu", target_env = "uclibc")))]
         {
             if let Some(version) = sys::os::glibc_version() {
                 if version < (2, 24) {

library/std/src/sys/unix/thread.rs

@@ -594,7 +594,8 @@ pub mod guard {
                 Some(stackaddr - guardsize..stackaddr)
             } else if cfg!(all(target_os = "linux", target_env = "musl")) {
                 Some(stackaddr - guardsize..stackaddr)
-            } else if cfg!(all(target_os = "linux", target_env = "gnu")) {
+            } else if cfg!(all(target_os = "linux", any(target_env = "gnu", target_env = "uclibc")))
+            {
                 // glibc used to include the guard area within the stack, as noted in the BUGS
                 // section of `man pthread_attr_getguardsize`.  This has been corrected starting
                 // with glibc 2.27, and in some distro backports, so the guard is now placed at the

library/unwind/src/lib.rs

@@ -63,7 +63,7 @@ cfg_if::cfg_if! {
 // don't want to duplicate it here.
 #[cfg(all(
     target_os = "linux",
-    target_env = "gnu",
+    any(target_env = "gnu", target_env = "uclibc"),
     not(feature = "llvm-libunwind"),
     not(feature = "system-llvm-libunwind")
 ))]
@@ -72,7 +72,7 @@ extern "C" {}
 
 #[cfg(all(
     target_os = "linux",
-    target_env = "gnu",
+    any(target_env = "gnu", target_env = "uclibc"),
     not(feature = "llvm-libunwind"),
     feature = "system-llvm-libunwind"
 ))]

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

@@ -220,6 +220,7 @@ target | std | host | notes
 `armv6-unknown-netbsd-eabihf` | ? |  |
 `armv6k-nintendo-3ds` | * |  | ARMv6K Nintendo 3DS, Horizon (Requires devkitARM toolchain)
 `armv7-apple-ios` | ✓ |  | ARMv7 iOS, Cortex-a8
+`armv7-unknown-linux-uclibceabihf` | ✓ | ? | ARMv7 Linux uClibc
 `armv7-unknown-freebsd` | ✓ | ✓ | ARMv7 FreeBSD
 `armv7-unknown-netbsd-eabihf` | ✓ | ✓ |
 `armv7-wrs-vxworks-eabihf` | ? |  |