Add aarch64 architecture for L4Re target

Author: farao

compiler/rustc_target/src/spec/mod.rs

@@ -1559,6 +1559,7 @@ supported_targets! {
 
     ("avr-none", avr_none),
 
+    ("aarch64-unknown-l4re-uclibc", aarch64_unknown_l4re_uclibc),
     ("x86_64-unknown-l4re-uclibc", x86_64_unknown_l4re_uclibc),
 
     ("aarch64-unknown-redox", aarch64_unknown_redox),

compiler/rustc_target/src/spec/targets/aarch64_unknown_l4re_uclibc.rs

@@ -0,0 +1,28 @@
+use crate::spec::{Arch, Cc, LinkerFlavor, Target, TargetOptions, base};
+
+pub(crate) fn target() -> Target {
+    let mut base = base::l4re::opts();
+
+    let extra_link_args = &["-zmax-page-size=0x1000", "-zcommon-page-size=0x1000"];
+    base.add_pre_link_args(LinkerFlavor::Unix(Cc::Yes), extra_link_args);
+    base.add_pre_link_args(LinkerFlavor::Unix(Cc::No), extra_link_args);
+
+    Target {
+        llvm_target: "aarch64-unknown-l4re-uclibc".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: Some("Arm64 L4Re".into()),
+            tier: Some(3),
+            host_tools: Some(false),
+            std: Some(true),
+        },
+        pointer_width: 64,
+        data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
+        arch: Arch::AArch64,
+        options: TargetOptions {
+            features: "+v8a".into(),
+            mcount: "__mcount".into(),
+            max_atomic_width: Some(128),
+            ..base
+        }
+    }
+}

src/bootstrap/src/core/sanity.rs

@@ -38,6 +38,7 @@ pub struct Finder {
 const STAGE0_MISSING_TARGETS: &[&str] = &[
     // just a dummy comment so the list doesn't get onelined
     "riscv64im-unknown-none-elf",
+    "aarch64-unknown-l4re-uclibc",
 ];
 
 /// Minimum version threshold for libstdc++ required when using prebuilt LLVM