Add Fuchsia support

Adds support for the x86_64-unknown-fuchsia target, which covers the
Fuchsia operating system.

src/librustc_back/target/fuchsia_base.rs

@@ -0,0 +1,39 @@
+// Copyright 2014 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.
+
+use target::TargetOptions;
+use std::default::Default;
+
+pub fn opts() -> TargetOptions {
+    TargetOptions {
+        dynamic_linking: true,
+        executables: true,
+        linker_is_gnu: true,
+        has_rpath: true,
+        pre_link_args: 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.
+            // TODO: doesn't seem to be supported by clang toolchain
+            //"-Wl,--as-needed".to_string(),
+
+            // Always enable NX protection when it is available
+            //"-Wl,-z,noexecstack".to_string(),
+        ],
+        position_independent_executables: true,
+        exe_allocation_crate: "alloc_system".to_string(),
+        has_elf_tls: true,
+        .. Default::default()
+    }
+}

src/librustc_back/target/mod.rs

@@ -67,6 +67,7 @@ mod solaris_base;
 mod windows_base;
 mod windows_msvc_base;
 mod thumb_base;
+mod fuchsia_base;
 
 pub type TargetResult = Result<Target, String>;
 
@@ -175,6 +176,8 @@ supported_targets! {
     ("x86_64-apple-darwin", x86_64_apple_darwin),
     ("i686-apple-darwin", i686_apple_darwin),
 
+    ("x86_64-unknown-fuchsia", x86_64_unknown_fuchsia),
+
     ("i386-apple-ios", i386_apple_ios),
     ("x86_64-apple-ios", x86_64_apple_ios),
     ("aarch64-apple-ios", aarch64_apple_ios),

src/librustc_back/target/x86_64_unknown_fuchsia.rs

@@ -0,0 +1,30 @@
+// Copyright 2016 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.
+
+use target::{Target, TargetResult};
+
+pub fn target() -> TargetResult {
+    let mut base = super::fuchsia_base::opts();
+    base.cpu = "x86-64".to_string();
+    base.max_atomic_width = Some(64);
+    base.pre_link_args.push("-m64".to_string());
+
+    Ok(Target {
+        llvm_target: "x86_64-unknown-fuchsia".to_string(),
+        target_endian: "little".to_string(),
+        target_pointer_width: "64".to_string(),
+        data_layout: "e-m:e-i64:64-f80:128-n8:16:32:64-S128".to_string(),
+        arch: "x86_64".to_string(),
+        target_os: "fuchsia".to_string(),
+        target_env: "".to_string(),
+        target_vendor: "unknown".to_string(),
+        options: base,
+    })
+}