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 std::default::Default;
50 use std::io::prelude::*;
64 mod windows_msvc_base;
66 /// Everything `rustc` knows about how to compile for a specific target.
68 /// Every field here must be specified, and has no default value.
69 #[derive(Clone, Debug)]
71 /// Target triple to pass to LLVM.
72 pub llvm_target: String,
73 /// String to use as the `target_endian` `cfg` variable.
74 pub target_endian: String,
75 /// String to use as the `target_pointer_width` `cfg` variable.
76 pub target_pointer_width: String,
77 /// OS name to use for conditional compilation.
78 pub target_os: String,
79 /// Environment name to use for conditional compilation.
80 pub target_env: String,
81 /// Vendor name to use for conditional compilation.
82 pub target_vendor: String,
83 /// Architecture to use for ABI considerations. Valid options: "x86",
84 /// "x86_64", "arm", "aarch64", "mips", "powerpc", and "powerpc64".
86 /// Optional settings with defaults.
87 pub options: TargetOptions,
90 /// Optional aspects of a target specification.
92 /// This has an implementation of `Default`, see each field for what the default is. In general,
93 /// these try to take "minimal defaults" that don't assume anything about the runtime they run in.
94 #[derive(Clone, Debug)]
95 pub struct TargetOptions {
96 /// [Data layout](http://llvm.org/docs/LangRef.html#data-layout) to pass to LLVM.
97 pub data_layout: Option<String>,
98 /// Linker to invoke. Defaults to "cc".
100 /// Archive utility to use when managing archives. Defaults to "ar".
103 /// Linker arguments that are unconditionally passed *before* any
104 /// user-defined libraries.
105 pub pre_link_args: Vec<String>,
106 /// Objects to link before all others, always found within the
108 pub pre_link_objects_exe: Vec<String>, // ... when linking an executable
109 pub pre_link_objects_dll: Vec<String>, // ... when linking a dylib
110 /// Linker arguments that are unconditionally passed after any
111 /// user-defined but before post_link_objects. Standard platform
112 /// libraries that should be always be linked to, usually go here.
113 pub late_link_args: Vec<String>,
114 /// Objects to link after all others, always found within the
116 pub post_link_objects: Vec<String>,
117 /// Linker arguments that are unconditionally passed *after* any
118 /// user-defined libraries.
119 pub post_link_args: Vec<String>,
121 /// Default CPU to pass to LLVM. Corresponds to `llc -mcpu=$cpu`. Defaults
124 /// Default target features to pass to LLVM. These features will *always* be
125 /// passed, and cannot be disabled even via `-C`. Corresponds to `llc
126 /// -mattr=$features`.
127 pub features: String,
128 /// Whether dynamic linking is available on this target. Defaults to false.
129 pub dynamic_linking: bool,
130 /// Whether executables are available on this target. iOS, for example, only allows static
131 /// libraries. Defaults to false.
132 pub executables: bool,
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 /// OS family to use for conditional compilation. Valid options: "unix", "windows".
155 pub target_family: Option<String>,
156 /// Whether the target toolchain is like OSX's. Only useful for compiling against iOS/OS X, in
157 /// particular running dsymutil and some other stuff like `-dead_strip`. Defaults to false.
158 pub is_like_osx: bool,
159 /// Whether the target toolchain is like Solaris's.
160 /// Only useful for compiling against Illumos/Solaris,
161 /// as they have a different set of linker flags. Defaults to false.
162 pub is_like_solaris: bool,
163 /// Whether the target toolchain is like Windows'. Only useful for compiling against Windows,
164 /// only really used for figuring out how to find libraries, since Windows uses its own
165 /// library naming convention. Defaults to false.
166 pub is_like_windows: bool,
167 pub is_like_msvc: bool,
168 /// Whether the target toolchain is like Android's. Only useful for compiling against Android.
169 /// Defaults to false.
170 pub is_like_android: bool,
171 /// Whether the linker support GNU-like arguments such as -O. Defaults to false.
172 pub linker_is_gnu: bool,
173 /// Whether the linker support rpaths or not. Defaults to false.
175 /// Whether to disable linking to compiler-rt. Defaults to false, as LLVM
176 /// will emit references to the functions that compiler-rt provides.
177 pub no_compiler_rt: bool,
178 /// Whether to disable linking to the default libraries, typically corresponds
179 /// to `-nodefaultlibs`. Defaults to true.
180 pub no_default_libraries: bool,
181 /// Dynamically linked executables can be compiled as position independent
182 /// if the default relocation model of position independent code is not
183 /// changed. This is a requirement to take advantage of ASLR, as otherwise
184 /// the functions in the executable are not randomized and can be used
185 /// during an exploit of a vulnerability in any code.
186 pub position_independent_executables: bool,
187 /// Format that archives should be emitted in. This affects whether we use
188 /// LLVM to assemble an archive or fall back to the system linker, and
189 /// currently only "gnu" is used to fall into LLVM. Unknown strings cause
190 /// the system linker to be used.
191 pub archive_format: String,
192 /// Is asm!() allowed? Defaults to true.
194 /// Whether the target uses a custom unwind resumption routine.
195 /// By default LLVM lowers `resume` instructions into calls to `_Unwind_Resume`
196 /// defined in libgcc. If this option is enabled, the target must provide
197 /// `eh_unwind_resume` lang item.
198 pub custom_unwind_resume: bool,
200 /// Default crate for allocation symbols to link against
201 pub lib_allocation_crate: String,
202 pub exe_allocation_crate: String,
204 /// Flag indicating whether ELF TLS (e.g. #[thread_local]) is available for
206 pub has_elf_tls: bool,
207 // This is mainly for easy compatibility with emscripten.
208 // If we give emcc .o files that are actually .bc files it
210 pub obj_is_bitcode: bool,
213 impl Default for TargetOptions {
214 /// Create a set of "sane defaults" for any target. This is still
215 /// incomplete, and if used for compilation, will certainly not work.
216 fn default() -> TargetOptions {
219 linker: option_env!("CFG_DEFAULT_LINKER").unwrap_or("cc").to_string(),
220 ar: option_env!("CFG_DEFAULT_AR").unwrap_or("ar").to_string(),
221 pre_link_args: Vec::new(),
222 post_link_args: Vec::new(),
223 cpu: "generic".to_string(),
224 features: "".to_string(),
225 dynamic_linking: false,
227 relocation_model: "pic".to_string(),
228 code_model: "default".to_string(),
229 disable_redzone: false,
230 eliminate_frame_pointer: true,
231 function_sections: true,
232 dll_prefix: "lib".to_string(),
233 dll_suffix: ".so".to_string(),
234 exe_suffix: "".to_string(),
235 staticlib_prefix: "lib".to_string(),
236 staticlib_suffix: ".a".to_string(),
239 is_like_solaris: false,
240 is_like_windows: false,
241 is_like_android: false,
243 linker_is_gnu: false,
245 no_compiler_rt: false,
246 no_default_libraries: true,
247 position_independent_executables: false,
248 pre_link_objects_exe: Vec::new(),
249 pre_link_objects_dll: Vec::new(),
250 post_link_objects: Vec::new(),
251 late_link_args: Vec::new(),
252 archive_format: "gnu".to_string(),
253 custom_unwind_resume: false,
254 lib_allocation_crate: "alloc_system".to_string(),
255 exe_allocation_crate: "alloc_system".to_string(),
258 obj_is_bitcode: false,
264 /// Given a function ABI, turn "System" into the correct ABI for this target.
265 pub fn adjust_abi(&self, abi: Abi) -> Abi {
268 if self.options.is_like_windows && self.arch == "x86" {
278 /// Load a target descriptor from a JSON object.
279 pub fn from_json(obj: Json) -> Target {
280 // this is 1. ugly, 2. error prone.
282 let get_req_field = |name: &str| {
284 .map(|s| s.as_string())
285 .and_then(|os| os.map(|s| s.to_string())) {
288 panic!("Field {} in target specification is required", name)
293 let get_opt_field = |name: &str, default: &str| {
294 obj.find(name).and_then(|s| s.as_string())
295 .map(|s| s.to_string())
296 .unwrap_or(default.to_string())
299 let mut base = Target {
300 llvm_target: get_req_field("llvm-target"),
301 target_endian: get_req_field("target-endian"),
302 target_pointer_width: get_req_field("target-pointer-width"),
303 arch: get_req_field("arch"),
304 target_os: get_req_field("os"),
305 target_env: get_opt_field("env", ""),
306 target_vendor: get_opt_field("vendor", "unknown"),
307 options: Default::default(),
311 ($key_name:ident) => ( {
312 let name = (stringify!($key_name)).replace("_", "-");
313 obj.find(&name[..]).map(|o| o.as_string()
314 .map(|s| base.options.$key_name = s.to_string()));
316 ($key_name:ident, bool) => ( {
317 let name = (stringify!($key_name)).replace("_", "-");
319 .map(|o| o.as_boolean()
320 .map(|s| base.options.$key_name = s));
322 ($key_name:ident, list) => ( {
323 let name = (stringify!($key_name)).replace("_", "-");
324 obj.find(&name[..]).map(|o| o.as_array()
325 .map(|v| base.options.$key_name = v.iter()
326 .map(|a| a.as_string().unwrap().to_string()).collect()
330 ($key_name:ident, optional) => ( {
331 let name = (stringify!($key_name)).replace("_", "-");
332 if let Some(o) = obj.find(&name[..]) {
333 base.options.$key_name = o
335 .map(|s| s.to_string() );
343 key!(relocation_model);
348 key!(staticlib_prefix);
349 key!(staticlib_suffix);
351 key!(data_layout, optional);
352 key!(dynamic_linking, bool);
353 key!(executables, bool);
354 key!(disable_redzone, bool);
355 key!(eliminate_frame_pointer, bool);
356 key!(function_sections, bool);
357 key!(target_family, optional);
358 key!(is_like_osx, bool);
359 key!(is_like_windows, bool);
360 key!(linker_is_gnu, bool);
361 key!(has_rpath, bool);
362 key!(no_compiler_rt, bool);
363 key!(no_default_libraries, bool);
364 key!(pre_link_args, list);
365 key!(post_link_args, list);
366 key!(archive_format);
367 key!(allow_asm, bool);
368 key!(custom_unwind_resume, bool);
373 /// Search RUST_TARGET_PATH for a JSON file specifying the given target
374 /// triple. Note that it could also just be a bare filename already, so also
375 /// check for that. If one of the hardcoded targets we know about, just
376 /// return it directly.
378 /// The error string could come from any of the APIs called, including
379 /// filesystem access and JSON decoding.
380 pub fn search(target: &str) -> Result<Target, String> {
382 use std::ffi::OsString;
384 use std::path::{Path, PathBuf};
387 fn load_file(path: &Path) -> Result<Target, String> {
388 let mut f = try!(File::open(path).map_err(|e| e.to_string()));
389 let mut contents = Vec::new();
390 try!(f.read_to_end(&mut contents).map_err(|e| e.to_string()));
391 let obj = try!(json::from_reader(&mut &contents[..])
392 .map_err(|e| e.to_string()));
393 Ok(Target::from_json(obj))
396 // this would use a match if stringify! were allowed in pattern position
397 macro_rules! load_specific {
398 ( $($name:ident),+ ) => (
401 let target = target.replace("-", "_");
404 else if target == stringify!($name) {
405 let t = $name::target();
406 debug!("Got builtin target: {:?}", t);
410 else if target == "x86_64-w64-mingw32" {
411 let t = x86_64_pc_windows_gnu::target();
413 } else if target == "i686-w64-mingw32" {
414 let t = i686_pc_windows_gnu::target();
422 x86_64_unknown_linux_gnu,
423 i686_unknown_linux_gnu,
424 mips_unknown_linux_gnu,
425 mipsel_unknown_linux_gnu,
426 powerpc_unknown_linux_gnu,
427 powerpc64_unknown_linux_gnu,
428 powerpc64le_unknown_linux_gnu,
429 arm_unknown_linux_gnueabi,
430 arm_unknown_linux_gnueabihf,
431 armv7_unknown_linux_gnueabihf,
432 aarch64_unknown_linux_gnu,
433 x86_64_unknown_linux_musl,
434 i686_unknown_linux_musl,
435 mips_unknown_linux_musl,
436 mipsel_unknown_linux_musl,
439 arm_linux_androideabi,
440 aarch64_linux_android,
442 i686_unknown_freebsd,
443 x86_64_unknown_freebsd,
445 i686_unknown_dragonfly,
446 x86_64_unknown_dragonfly,
448 x86_64_unknown_bitrig,
449 x86_64_unknown_openbsd,
450 x86_64_unknown_netbsd,
451 x86_64_rumprun_netbsd,
464 x86_64_pc_windows_gnu,
467 x86_64_pc_windows_msvc,
468 i686_pc_windows_msvc,
471 asmjs_unknown_emscripten
475 let path = Path::new(target);
478 return load_file(&path);
482 let mut target = target.to_string();
483 target.push_str(".json");
484 PathBuf::from(target)
487 let target_path = env::var_os("RUST_TARGET_PATH")
488 .unwrap_or(OsString::new());
490 // FIXME 16351: add a sane default search path?
492 for dir in env::split_paths(&target_path) {
493 let p = dir.join(&path);
495 return load_file(&p);
499 Err(format!("Could not find specification for target {:?}", target))
503 fn maybe_jemalloc() -> String {
504 if cfg!(disable_jemalloc) {
505 "alloc_system".to_string()
507 "alloc_jemalloc".to_string()