1 // Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! [Flexible target specification.](https://github.com/rust-lang/rfcs/pull/131)
13 //! Rust targets a wide variety of usecases, and in the interest of flexibility,
14 //! allows new target triples to be defined in configuration files. Most users
15 //! will not need to care about these, but this is invaluable when porting Rust
16 //! to a new platform, and allows for an unprecedented level of control over how
17 //! the compiler works.
19 //! # Using custom targets
21 //! A target triple, as passed via `rustc --target=TRIPLE`, will first be
22 //! compared against the list of built-in targets. This is to ease distributing
23 //! rustc (no need for configuration files) and also to hold these built-in
24 //! targets as immutable and sacred. If `TRIPLE` is not one of the built-in
25 //! targets, rustc will check if a file named `TRIPLE` exists. If it does, it
26 //! will be loaded as the target configuration. If the file does not exist,
27 //! rustc will search each directory in the environment variable
28 //! `RUST_TARGET_PATH` for a file named `TRIPLE.json`. The first one found will
29 //! be loaded. If no file is found in any of those directories, a fatal error
30 //! will be given. `RUST_TARGET_PATH` includes `/etc/rustc` as its last entry,
31 //! to be searched by default.
33 //! Projects defining their own targets should use
34 //! `--target=path/to/my-awesome-platform.json` instead of adding to
35 //! `RUST_TARGET_PATH`.
37 //! # Defining a new target
39 //! Targets are defined using [JSON](http://json.org/). The `Target` struct in
40 //! this module defines the format the JSON file should take, though each
41 //! underscore in the field names should be replaced with a hyphen (`-`) in the
42 //! JSON file. Some fields are required in every target specification, such as
43 //! `data-layout`, `llvm-target`, `target-endian`, `target-pointer-width`, and
44 //! `arch`. In general, options passed to rustc with `-C` override the target's
45 //! settings, though `target-feature` and `link-args` will *add* to the list
46 //! specified by the target, rather than replace.
48 use serialize::json::Json;
49 use syntax::{diagnostic, abi};
50 use std::default::Default;
51 use std::old_io::fs::PathExtensions;
65 mod arm_linux_androideabi;
66 mod arm_unknown_linux_gnueabi;
67 mod arm_unknown_linux_gnueabihf;
68 mod aarch64_apple_ios;
69 mod aarch64_linux_android;
70 mod aarch64_unknown_linux_gnu;
71 mod i686_apple_darwin;
72 mod i686_pc_windows_gnu;
73 mod i686_unknown_dragonfly;
74 mod i686_unknown_linux_gnu;
75 mod mips_unknown_linux_gnu;
76 mod mipsel_unknown_linux_gnu;
77 mod powerpc_unknown_linux_gnu;
78 mod x86_64_apple_darwin;
80 mod x86_64_pc_windows_gnu;
81 mod x86_64_unknown_freebsd;
82 mod x86_64_unknown_dragonfly;
83 mod x86_64_unknown_linux_gnu;
84 mod x86_64_unknown_openbsd;
86 /// Everything `rustc` knows about how to compile for a specific target.
88 /// Every field here must be specified, and has no default value.
89 #[derive(Clone, Debug)]
91 /// [Data layout](http://llvm.org/docs/LangRef.html#data-layout) to pass to LLVM.
92 pub data_layout: String,
93 /// Target triple to pass to LLVM.
94 pub llvm_target: String,
95 /// String to use as the `target_endian` `cfg` variable.
96 pub target_endian: String,
97 /// String to use as the `target_pointer_width` `cfg` variable.
98 pub target_pointer_width: String,
99 /// OS name to use for conditional compilation.
100 pub target_os: String,
101 /// Architecture to use for ABI considerations. Valid options: "x86", "x86_64", "arm",
102 /// "aarch64", "mips", and "powerpc". "mips" includes "mipsel".
104 /// Optional settings with defaults.
105 pub options: TargetOptions,
108 /// Optional aspects of a target specification.
110 /// This has an implementation of `Default`, see each field for what the default is. In general,
111 /// these try to take "minimal defaults" that don't assume anything about the runtime they run in.
112 #[derive(Clone, Debug)]
113 pub struct TargetOptions {
114 /// Linker to invoke. Defaults to "cc".
116 /// Linker arguments that are unconditionally passed *before* any user-defined libraries.
117 pub pre_link_args: Vec<String>,
118 /// Linker arguments that are unconditionally passed *after* any user-defined libraries.
119 pub post_link_args: Vec<String>,
120 /// Default CPU to pass to LLVM. Corresponds to `llc -mcpu=$cpu`. Defaults to "default".
122 /// Default target features to pass to LLVM. These features will *always* be passed, and cannot
123 /// be disabled even via `-C`. Corresponds to `llc -mattr=$features`.
124 pub features: String,
125 /// Whether dynamic linking is available on this target. Defaults to false.
126 pub dynamic_linking: bool,
127 /// Whether executables are available on this target. iOS, for example, only allows static
128 /// libraries. Defaults to false.
129 pub executables: bool,
130 /// Whether LLVM's segmented stack prelude is supported by whatever runtime is available.
131 /// Will emit stack checks and calls to __morestack. Defaults to false.
133 /// Relocation model to use in object file. Corresponds to `llc
134 /// -relocation-model=$relocation_model`. Defaults to "pic".
135 pub relocation_model: String,
136 /// Code model to use. Corresponds to `llc -code-model=$code_model`. Defaults to "default".
137 pub code_model: String,
138 /// Do not emit code that uses the "red zone", if the ABI has one. Defaults to false.
139 pub disable_redzone: bool,
140 /// Eliminate frame pointers from stack frames if possible. Defaults to true.
141 pub eliminate_frame_pointer: bool,
142 /// Emit each function in its own section. Defaults to true.
143 pub function_sections: bool,
144 /// String to prepend to the name of every dynamic library. Defaults to "lib".
145 pub dll_prefix: String,
146 /// String to append to the name of every dynamic library. Defaults to ".so".
147 pub dll_suffix: String,
148 /// String to append to the name of every executable.
149 pub exe_suffix: String,
150 /// String to prepend to the name of every static library. Defaults to "lib".
151 pub staticlib_prefix: String,
152 /// String to append to the name of every static library. Defaults to ".a".
153 pub staticlib_suffix: String,
154 /// Whether the target toolchain is like OSX's. Only useful for compiling against iOS/OS X, in
155 /// particular running dsymutil and some other stuff like `-dead_strip`. Defaults to false.
156 pub is_like_osx: bool,
157 /// Whether the target toolchain is like Windows'. Only useful for compiling against Windows,
158 /// only realy used for figuring out how to find libraries, since Windows uses its own
159 /// library naming convention. Defaults to false.
160 pub is_like_windows: bool,
161 /// Whether the target toolchain is like Android's. Only useful for compiling against Android.
162 /// Defaults to false.
163 pub is_like_android: bool,
164 /// Whether the linker support GNU-like arguments such as -O. Defaults to false.
165 pub linker_is_gnu: bool,
166 /// Whether the linker support rpaths or not. Defaults to false.
168 /// Whether to disable linking to compiler-rt. Defaults to false, as LLVM will emit references
169 /// to the functions that compiler-rt provides.
170 pub no_compiler_rt: bool,
171 /// Dynamically linked executables can be compiled as position independent if the default
172 /// relocation model of position independent code is not changed. This is a requirement to take
173 /// advantage of ASLR, as otherwise the functions in the executable are not randomized and can
174 /// be used during an exploit of a vulnerability in any code.
175 pub position_independent_executables: bool,
178 impl Default for TargetOptions {
179 /// Create a set of "sane defaults" for any target. This is still incomplete, and if used for
180 /// compilation, will certainly not work.
181 fn default() -> TargetOptions {
183 linker: "cc".to_string(),
184 pre_link_args: Vec::new(),
185 post_link_args: Vec::new(),
186 cpu: "generic".to_string(),
187 features: "".to_string(),
188 dynamic_linking: false,
191 relocation_model: "pic".to_string(),
192 code_model: "default".to_string(),
193 disable_redzone: false,
194 eliminate_frame_pointer: true,
195 function_sections: true,
196 dll_prefix: "lib".to_string(),
197 dll_suffix: ".so".to_string(),
198 exe_suffix: "".to_string(),
199 staticlib_prefix: "lib".to_string(),
200 staticlib_suffix: ".a".to_string(),
202 is_like_windows: false,
203 is_like_android: false,
204 linker_is_gnu: false,
206 no_compiler_rt: false,
207 position_independent_executables: false,
213 /// Given a function ABI, turn "System" into the correct ABI for this target.
214 pub fn adjust_abi(&self, abi: abi::Abi) -> abi::Abi {
217 if self.options.is_like_windows && self.arch == "x86" {
227 /// Load a target descriptor from a JSON object.
228 pub fn from_json(obj: Json) -> Target {
229 // this is 1. ugly, 2. error prone.
232 let handler = diagnostic::default_handler(diagnostic::Auto, None, true);
234 let get_req_field = |name: &str| {
236 .map(|s| s.as_string())
237 .and_then(|os| os.map(|s| s.to_string())) {
240 handler.fatal(&format!("Field {} in target specification is required", name)[])
244 let mut base = Target {
245 data_layout: get_req_field("data-layout"),
246 llvm_target: get_req_field("llvm-target"),
247 target_endian: get_req_field("target-endian"),
248 target_pointer_width: get_req_field("target-pointer-width"),
249 arch: get_req_field("arch"),
250 target_os: get_req_field("os"),
251 options: Default::default(),
255 ($key_name:ident) => ( {
256 let name = (stringify!($key_name)).replace("_", "-");
257 obj.find(&name[..]).map(|o| o.as_string()
258 .map(|s| base.options.$key_name = s.to_string()));
260 ($key_name:ident, bool) => ( {
261 let name = (stringify!($key_name)).replace("_", "-");
263 .map(|o| o.as_boolean()
264 .map(|s| base.options.$key_name = s));
266 ($key_name:ident, list) => ( {
267 let name = (stringify!($key_name)).replace("_", "-");
268 obj.find(&name[..]).map(|o| o.as_array()
269 .map(|v| base.options.$key_name = v.iter()
270 .map(|a| a.as_string().unwrap().to_string()).collect()
278 key!(relocation_model);
283 key!(staticlib_prefix);
284 key!(staticlib_suffix);
286 key!(dynamic_linking, bool);
287 key!(executables, bool);
288 key!(morestack, bool);
289 key!(disable_redzone, bool);
290 key!(eliminate_frame_pointer, bool);
291 key!(function_sections, bool);
292 key!(is_like_osx, bool);
293 key!(is_like_windows, bool);
294 key!(linker_is_gnu, bool);
295 key!(has_rpath, bool);
296 key!(no_compiler_rt, bool);
297 key!(pre_link_args, list);
298 key!(post_link_args, list);
303 /// Search RUST_TARGET_PATH for a JSON file specifying the given target triple. Note that it
304 /// could also just be a bare filename already, so also check for that. If one of the hardcoded
305 /// targets we know about, just return it directly.
307 /// The error string could come from any of the APIs called, including filesystem access and
309 pub fn search(target: &str) -> Result<Target, String> {
311 use std::ffi::OsString;
312 use std::old_io::File;
313 use std::old_path::Path;
316 fn load_file(path: &Path) -> Result<Target, String> {
317 let mut f = try!(File::open(path).map_err(|e| format!("{:?}", e)));
318 let obj = try!(json::from_reader(&mut f).map_err(|e| format!("{:?}", e)));
319 Ok(Target::from_json(obj))
322 // this would use a match if stringify! were allowed in pattern position
323 macro_rules! load_specific {
324 ( $($name:ident),+ ) => (
326 let target = target.replace("-", "_");
329 else if target == stringify!($name) {
330 let t = $name::target();
331 debug!("Got builtin target: {:?}", t);
335 else if target == "x86_64-w64-mingw32" {
336 let t = x86_64_pc_windows_gnu::target();
338 } else if target == "i686-w64-mingw32" {
339 let t = i686_pc_windows_gnu::target();
347 x86_64_unknown_linux_gnu,
348 i686_unknown_linux_gnu,
349 mips_unknown_linux_gnu,
350 mipsel_unknown_linux_gnu,
351 powerpc_unknown_linux_gnu,
352 arm_unknown_linux_gnueabi,
353 arm_unknown_linux_gnueabihf,
354 aarch64_unknown_linux_gnu,
356 arm_linux_androideabi,
357 aarch64_linux_android,
359 x86_64_unknown_freebsd,
361 i686_unknown_dragonfly,
362 x86_64_unknown_dragonfly,
364 x86_64_unknown_openbsd,
375 x86_64_pc_windows_gnu,
380 let path = Path::new(target);
383 return load_file(&path);
387 let mut target = target.to_string();
388 target.push_str(".json");
392 let target_path = env::var_os("RUST_TARGET_PATH").unwrap_or(OsString::from_str(""));
394 // FIXME 16351: add a sane default search path?
396 for dir in env::split_paths(&target_path) {
397 let p = dir.join(path.clone());
399 return load_file(&p);
403 Err(format!("Could not find specification for target {:?}", target))