Add new Tier-3 target: loongarch64-unknown-linux-musl

MCP: https://github.com/rust-lang/compiler-team/issues/518

compiler/rustc_target/src/spec/mod.rs

@@ -1404,6 +1404,7 @@ fn $module() {
     ("i686-unknown-linux-gnu", i686_unknown_linux_gnu),
     ("i586-unknown-linux-gnu", i586_unknown_linux_gnu),
     ("loongarch64-unknown-linux-gnu", loongarch64_unknown_linux_gnu),
+    ("loongarch64-unknown-linux-musl", loongarch64_unknown_linux_musl),
     ("m68k-unknown-linux-gnu", m68k_unknown_linux_gnu),
     ("csky-unknown-linux-gnuabiv2", csky_unknown_linux_gnuabiv2),
     ("csky-unknown-linux-gnuabiv2hf", csky_unknown_linux_gnuabiv2hf),

compiler/rustc_target/src/spec/targets/loongarch64_unknown_linux_musl.rs

@@ -0,0 +1,19 @@
+use crate::spec::{base, Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "loongarch64-unknown-linux-musl".into(),
+        description: None,
+        pointer_width: 64,
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n64-S128".into(),
+        arch: "loongarch64".into(),
+        options: TargetOptions {
+            cpu: "generic".into(),
+            features: "+f,+d".into(),
+            llvm_abiname: "lp64d".into(),
+            max_atomic_width: Some(64),
+            crt_static_default: false,
+            ..base::linux_musl::opts()
+        },
+    }
+}

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

@@ -169,6 +169,7 @@ target | std | notes
 `i686-unknown-freebsd` | ✓ | 32-bit FreeBSD [^x86_32-floats-return-ABI]
 `i686-unknown-linux-musl` | ✓ | 32-bit Linux with musl 1.2.3 [^x86_32-floats-return-ABI]
 [`i686-unknown-uefi`](platform-support/unknown-uefi.md) | * | 32-bit UEFI
+[`loongarch64-unknown-linux-musl`](platform-support/loongarch-linux.md) | ? |  | LoongArch64 Linux (LP64D ABI)
 [`loongarch64-unknown-none`](platform-support/loongarch-none.md) | * |  | LoongArch64 Bare-metal (LP64D ABI)
 [`loongarch64-unknown-none-softfloat`](platform-support/loongarch-none.md) | * |  | LoongArch64 Bare-metal (LP64S ABI)
 [`nvptx64-nvidia-cuda`](platform-support/nvptx64-nvidia-cuda.md) | * | --emit=asm generates PTX code that [runs on NVIDIA GPUs]