Rollup merge of rust-lang#53233 - andre-richter:master, r=alexcrichton

targets: aarch64: Add bare-metal aarch64 target

A generic AArch64 target that can be used for writing bare-metal code
for 64-bit ARM architectures.

src/librustc_target/spec/aarch64_unknown_none.rs

@@ -0,0 +1,46 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Generic AArch64 target for bare-metal code
+//
+// Can be used in conjunction with the `target-feature` and
+// `target-cpu` compiler flags to opt-in more hardware-specific
+// features.
+//
+// For example, `-C target-cpu=cortex-a53`.
+
+use super::{LldFlavor, LinkerFlavor, Target, TargetOptions, PanicStrategy};
+
+pub fn target() -> Result<Target, String> {
+ let opts = TargetOptions {
+ linker: Some("rust-lld".to_owned()),
+ executables: true,
+ relocation_model: "static".to_string(),
+ disable_redzone: true,
+ linker_is_gnu: true,
+ max_atomic_width: Some(128),
+ panic_strategy: PanicStrategy::Abort,
+ abi_blacklist: super::arm_base::abi_blacklist(),
+ .. Default::default()
+ };
+ Ok(Target {
+ llvm_target: "aarch64-unknown-none".to_string(),
+ target_endian: "little".to_string(),
+ target_pointer_width: "64".to_string(),
+ target_c_int_width: "32".to_string(),
+ target_os: "none".to_string(),
+ target_env: "".to_string(),
+ target_vendor: "".to_string(),
+ data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".to_string(),
+ arch: "aarch64".to_string(),
+ linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
+ options: opts,
+ })
+}

src/librustc_target/spec/mod.rs

@@ -379,6 +379,8 @@ supported_targets! {
  ("x86_64-unknown-hermit", x86_64_unknown_hermit),
 
  ("riscv32imac-unknown-none-elf", riscv32imac_unknown_none_elf),
+
+ ("aarch64-unknown-none", aarch64_unknown_none),
 }
 
 /// Everything `rustc` knows about how to compile for a specific target.