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
32 //! Projects defining their own targets should use
33 //! `--target=path/to/my-awesome-platform.json` instead of adding to
34 //! `RUST_TARGET_PATH`.
36 //! # Defining a new target
38 //! Targets are defined using [JSON](http://json.org/). The `Target` struct in
39 //! this module defines the format the JSON file should take, though each
40 //! underscore in the field names should be replaced with a hyphen (`-`) in the
41 //! JSON file. Some fields are required in every target specification, such as
42 //! `llvm-target`, `target-endian`, `target-pointer-width`, `data-layout`,
43 //! `arch`, and `os`. In general, options passed to rustc with `-C` override
44 //! the target's settings, though `target-feature` and `link-args` will *add*
45 //! to the list specified by the target, rather than replace.
47 use serialize::json::{Json, ToJson};
48 use std::collections::BTreeMap;
49 use std::default::Default;
51 use std::path::{Path, PathBuf};
52 use std::str::FromStr;
53 use spec::abi::{Abi, lookup as lookup_abi};
72 mod windows_msvc_base;
79 #[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd, Hash,
80 RustcEncodable, RustcDecodable)]
81 pub enum LinkerFlavor {
89 #[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd, Hash,
90 RustcEncodable, RustcDecodable)]
99 fn from_str(s: &str) -> Option<Self> {
101 "darwin" => LldFlavor::Ld64,
102 "gnu" => LldFlavor::Ld,
103 "link" => LldFlavor::Link,
104 "wasm" => LldFlavor::Wasm,
110 impl ToJson for LldFlavor {
111 fn to_json(&self) -> Json {
113 LldFlavor::Ld64 => "darwin",
114 LldFlavor::Ld => "gnu",
115 LldFlavor::Link => "link",
116 LldFlavor::Wasm => "wasm",
121 impl ToJson for LinkerFlavor {
122 fn to_json(&self) -> Json {
123 self.desc().to_json()
126 macro_rules! flavor_mappings {
127 ($((($($flavor:tt)*), $string:expr),)*) => (
129 pub const fn one_of() -> &'static str {
130 concat!("one of: ", $($string, " ",)+)
133 pub fn from_str(s: &str) -> Option<Self> {
135 $($string => $($flavor)*,)+
140 pub fn desc(&self) -> &str {
142 $($($flavor)* => $string,)+
151 ((LinkerFlavor::Em), "em"),
152 ((LinkerFlavor::Gcc), "gcc"),
153 ((LinkerFlavor::Ld), "ld"),
154 ((LinkerFlavor::Msvc), "msvc"),
155 ((LinkerFlavor::Lld(LldFlavor::Wasm)), "wasm-ld"),
156 ((LinkerFlavor::Lld(LldFlavor::Ld64)), "ld64.lld"),
157 ((LinkerFlavor::Lld(LldFlavor::Ld)), "ld.lld"),
158 ((LinkerFlavor::Lld(LldFlavor::Link)), "lld-link"),
161 #[derive(Clone, Copy, Debug, PartialEq, Hash, RustcEncodable, RustcDecodable)]
162 pub enum PanicStrategy {
168 pub fn desc(&self) -> &str {
170 PanicStrategy::Unwind => "unwind",
171 PanicStrategy::Abort => "abort",
176 impl ToJson for PanicStrategy {
177 fn to_json(&self) -> Json {
179 PanicStrategy::Abort => "abort".to_json(),
180 PanicStrategy::Unwind => "unwind".to_json(),
185 #[derive(Clone, Copy, Debug, PartialEq, Hash, RustcEncodable, RustcDecodable)]
186 pub enum RelroLevel {
194 pub fn desc(&self) -> &str {
196 RelroLevel::Full => "full",
197 RelroLevel::Partial => "partial",
198 RelroLevel::Off => "off",
199 RelroLevel::None => "none",
204 impl FromStr for RelroLevel {
207 fn from_str(s: &str) -> Result<RelroLevel, ()> {
209 "full" => Ok(RelroLevel::Full),
210 "partial" => Ok(RelroLevel::Partial),
211 "off" => Ok(RelroLevel::Off),
212 "none" => Ok(RelroLevel::None),
218 impl ToJson for RelroLevel {
219 fn to_json(&self) -> Json {
221 RelroLevel::Full => "full".to_json(),
222 RelroLevel::Partial => "partial".to_json(),
223 RelroLevel::Off => "off".to_json(),
224 RelroLevel::None => "None".to_json(),
229 pub type LinkArgs = BTreeMap<LinkerFlavor, Vec<String>>;
230 pub type TargetResult = Result<Target, String>;
232 macro_rules! supported_targets {
233 ( $(($triple:expr, $module:ident),)+ ) => (
236 /// List of supported targets
237 const TARGETS: &'static [&'static str] = &[$($triple),*];
239 fn load_specific(target: &str) -> TargetResult {
243 let mut t = $module::target()?;
244 t.options.is_builtin = true;
246 // round-trip through the JSON parser to ensure at
247 // run-time that the parser works correctly
248 t = Target::from_json(t.to_json())?;
249 debug!("Got builtin target: {:?}", t);
253 _ => Err(format!("Unable to find target: {}", target))
257 pub fn get_targets() -> Box<dyn Iterator<Item=String>> {
258 Box::new(TARGETS.iter().filter_map(|t| -> Option<String> {
260 .and(Ok(t.to_string()))
266 mod test_json_encode_decode {
267 use serialize::json::ToJson;
269 $(use super::$module;)*
274 // Grab the TargetResult struct. If we successfully retrieved
275 // a Target, then the test JSON encoding/decoding can run for this
276 // Target on this testing platform (i.e., checking the iOS targets
277 // only on a Mac test platform).
278 let _ = $module::target().map(|original| {
279 let as_json = original.to_json();
280 let parsed = Target::from_json(as_json).unwrap();
281 assert_eq!(original, parsed);
290 ("x86_64-unknown-linux-gnu", x86_64_unknown_linux_gnu),
291 ("x86_64-unknown-linux-gnux32", x86_64_unknown_linux_gnux32),
292 ("i686-unknown-linux-gnu", i686_unknown_linux_gnu),
293 ("i586-unknown-linux-gnu", i586_unknown_linux_gnu),
294 ("mips-unknown-linux-gnu", mips_unknown_linux_gnu),
295 ("mips64-unknown-linux-gnuabi64", mips64_unknown_linux_gnuabi64),
296 ("mips64el-unknown-linux-gnuabi64", mips64el_unknown_linux_gnuabi64),
297 ("mipsel-unknown-linux-gnu", mipsel_unknown_linux_gnu),
298 ("powerpc-unknown-linux-gnu", powerpc_unknown_linux_gnu),
299 ("powerpc-unknown-linux-gnuspe", powerpc_unknown_linux_gnuspe),
300 ("powerpc-unknown-linux-musl", powerpc_unknown_linux_musl),
301 ("powerpc64-unknown-linux-gnu", powerpc64_unknown_linux_gnu),
302 ("powerpc64-unknown-linux-musl", powerpc64_unknown_linux_musl),
303 ("powerpc64le-unknown-linux-gnu", powerpc64le_unknown_linux_gnu),
304 ("powerpc64le-unknown-linux-musl", powerpc64le_unknown_linux_musl),
305 ("s390x-unknown-linux-gnu", s390x_unknown_linux_gnu),
306 ("sparc-unknown-linux-gnu", sparc_unknown_linux_gnu),
307 ("sparc64-unknown-linux-gnu", sparc64_unknown_linux_gnu),
308 ("arm-unknown-linux-gnueabi", arm_unknown_linux_gnueabi),
309 ("arm-unknown-linux-gnueabihf", arm_unknown_linux_gnueabihf),
310 ("arm-unknown-linux-musleabi", arm_unknown_linux_musleabi),
311 ("arm-unknown-linux-musleabihf", arm_unknown_linux_musleabihf),
312 ("armv4t-unknown-linux-gnueabi", armv4t_unknown_linux_gnueabi),
313 ("armv5te-unknown-linux-gnueabi", armv5te_unknown_linux_gnueabi),
314 ("armv5te-unknown-linux-musleabi", armv5te_unknown_linux_musleabi),
315 ("armv7-unknown-linux-gnueabihf", armv7_unknown_linux_gnueabihf),
316 ("armv7-unknown-linux-musleabihf", armv7_unknown_linux_musleabihf),
317 ("aarch64-unknown-linux-gnu", aarch64_unknown_linux_gnu),
319 ("aarch64-unknown-linux-musl", aarch64_unknown_linux_musl),
320 ("x86_64-unknown-linux-musl", x86_64_unknown_linux_musl),
321 ("i686-unknown-linux-musl", i686_unknown_linux_musl),
322 ("i586-unknown-linux-musl", i586_unknown_linux_musl),
323 ("mips-unknown-linux-musl", mips_unknown_linux_musl),
324 ("mipsel-unknown-linux-musl", mipsel_unknown_linux_musl),
326 ("mips-unknown-linux-uclibc", mips_unknown_linux_uclibc),
327 ("mipsel-unknown-linux-uclibc", mipsel_unknown_linux_uclibc),
329 ("i686-linux-android", i686_linux_android),
330 ("x86_64-linux-android", x86_64_linux_android),
331 ("arm-linux-androideabi", arm_linux_androideabi),
332 ("armv7-linux-androideabi", armv7_linux_androideabi),
333 ("aarch64-linux-android", aarch64_linux_android),
335 ("aarch64-unknown-freebsd", aarch64_unknown_freebsd),
336 ("i686-unknown-freebsd", i686_unknown_freebsd),
337 ("x86_64-unknown-freebsd", x86_64_unknown_freebsd),
339 ("i686-unknown-dragonfly", i686_unknown_dragonfly),
340 ("x86_64-unknown-dragonfly", x86_64_unknown_dragonfly),
342 ("x86_64-unknown-bitrig", x86_64_unknown_bitrig),
344 ("aarch64-unknown-openbsd", aarch64_unknown_openbsd),
345 ("i686-unknown-openbsd", i686_unknown_openbsd),
346 ("x86_64-unknown-openbsd", x86_64_unknown_openbsd),
348 ("aarch64-unknown-netbsd", aarch64_unknown_netbsd),
349 ("armv6-unknown-netbsd-eabihf", armv6_unknown_netbsd_eabihf),
350 ("armv7-unknown-netbsd-eabihf", armv7_unknown_netbsd_eabihf),
351 ("i686-unknown-netbsd", i686_unknown_netbsd),
352 ("powerpc-unknown-netbsd", powerpc_unknown_netbsd),
353 ("sparc64-unknown-netbsd", sparc64_unknown_netbsd),
354 ("x86_64-unknown-netbsd", x86_64_unknown_netbsd),
355 ("x86_64-rumprun-netbsd", x86_64_rumprun_netbsd),
357 ("i686-unknown-haiku", i686_unknown_haiku),
358 ("x86_64-unknown-haiku", x86_64_unknown_haiku),
360 ("x86_64-apple-darwin", x86_64_apple_darwin),
361 ("i686-apple-darwin", i686_apple_darwin),
363 ("aarch64-fuchsia", aarch64_fuchsia),
364 ("x86_64-fuchsia", x86_64_fuchsia),
366 ("x86_64-unknown-l4re-uclibc", x86_64_unknown_l4re_uclibc),
368 ("x86_64-unknown-redox", x86_64_unknown_redox),
370 ("i386-apple-ios", i386_apple_ios),
371 ("x86_64-apple-ios", x86_64_apple_ios),
372 ("aarch64-apple-ios", aarch64_apple_ios),
373 ("armv7-apple-ios", armv7_apple_ios),
374 ("armv7s-apple-ios", armv7s_apple_ios),
376 ("armebv7r-none-eabi", armebv7r_none_eabi),
377 ("armebv7r-none-eabihf", armebv7r_none_eabihf),
378 ("armv7r-none-eabi", armv7r_none_eabi),
379 ("armv7r-none-eabihf", armv7r_none_eabihf),
381 ("x86_64-sun-solaris", x86_64_sun_solaris),
382 ("sparcv9-sun-solaris", sparcv9_sun_solaris),
384 ("x86_64-pc-windows-gnu", x86_64_pc_windows_gnu),
385 ("i686-pc-windows-gnu", i686_pc_windows_gnu),
387 ("aarch64-pc-windows-msvc", aarch64_pc_windows_msvc),
388 ("x86_64-pc-windows-msvc", x86_64_pc_windows_msvc),
389 ("i686-pc-windows-msvc", i686_pc_windows_msvc),
390 ("i586-pc-windows-msvc", i586_pc_windows_msvc),
391 ("thumbv7a-pc-windows-msvc", thumbv7a_pc_windows_msvc),
393 ("asmjs-unknown-emscripten", asmjs_unknown_emscripten),
394 ("wasm32-unknown-emscripten", wasm32_unknown_emscripten),
395 ("wasm32-unknown-unknown", wasm32_unknown_unknown),
396 ("wasm32-experimental-emscripten", wasm32_experimental_emscripten),
398 ("thumbv6m-none-eabi", thumbv6m_none_eabi),
399 ("thumbv7m-none-eabi", thumbv7m_none_eabi),
400 ("thumbv7em-none-eabi", thumbv7em_none_eabi),
401 ("thumbv7em-none-eabihf", thumbv7em_none_eabihf),
403 ("msp430-none-elf", msp430_none_elf),
405 ("aarch64-unknown-cloudabi", aarch64_unknown_cloudabi),
406 ("armv7-unknown-cloudabi-eabihf", armv7_unknown_cloudabi_eabihf),
407 ("i686-unknown-cloudabi", i686_unknown_cloudabi),
408 ("x86_64-unknown-cloudabi", x86_64_unknown_cloudabi),
410 ("aarch64-unknown-hermit", aarch64_unknown_hermit),
411 ("x86_64-unknown-hermit", x86_64_unknown_hermit),
413 ("riscv32imc-unknown-none-elf", riscv32imc_unknown_none_elf),
414 ("riscv32imac-unknown-none-elf", riscv32imac_unknown_none_elf),
416 ("aarch64-unknown-none", aarch64_unknown_none),
418 ("x86_64-fortanix-unknown-sgx", x86_64_fortanix_unknown_sgx),
421 /// Everything `rustc` knows about how to compile for a specific target.
423 /// Every field here must be specified, and has no default value.
424 #[derive(PartialEq, Clone, Debug)]
426 /// Target triple to pass to LLVM.
427 pub llvm_target: String,
428 /// String to use as the `target_endian` `cfg` variable.
429 pub target_endian: String,
430 /// String to use as the `target_pointer_width` `cfg` variable.
431 pub target_pointer_width: String,
432 /// Width of c_int type
433 pub target_c_int_width: String,
434 /// OS name to use for conditional compilation.
435 pub target_os: String,
436 /// Environment name to use for conditional compilation.
437 pub target_env: String,
438 /// Vendor name to use for conditional compilation.
439 pub target_vendor: String,
440 /// Architecture to use for ABI considerations. Valid options: "x86",
441 /// "x86_64", "arm", "aarch64", "mips", "powerpc", and "powerpc64".
443 /// [Data layout](http://llvm.org/docs/LangRef.html#data-layout) to pass to LLVM.
444 pub data_layout: String,
446 pub linker_flavor: LinkerFlavor,
447 /// Optional settings with defaults.
448 pub options: TargetOptions,
451 pub trait HasTargetSpec {
452 fn target_spec(&self) -> &Target;
455 impl HasTargetSpec for Target {
456 fn target_spec(&self) -> &Target {
461 /// Optional aspects of a target specification.
463 /// This has an implementation of `Default`, see each field for what the default is. In general,
464 /// these try to take "minimal defaults" that don't assume anything about the runtime they run in.
465 #[derive(PartialEq, Clone, Debug)]
466 pub struct TargetOptions {
467 /// Whether the target is built-in or loaded from a custom target specification.
468 pub is_builtin: bool,
471 pub linker: Option<String>,
474 pub lld_flavor: LldFlavor,
476 /// Linker arguments that are passed *before* any user-defined libraries.
477 pub pre_link_args: LinkArgs, // ... unconditionally
478 pub pre_link_args_crt: LinkArgs, // ... when linking with a bundled crt
479 /// Objects to link before all others, always found within the
481 pub pre_link_objects_exe: Vec<String>, // ... when linking an executable, unconditionally
482 pub pre_link_objects_exe_crt: Vec<String>, // ... when linking an executable with a bundled crt
483 pub pre_link_objects_dll: Vec<String>, // ... when linking a dylib
484 /// Linker arguments that are unconditionally passed after any
485 /// user-defined but before post_link_objects. Standard platform
486 /// libraries that should be always be linked to, usually go here.
487 pub late_link_args: LinkArgs,
488 /// Objects to link after all others, always found within the
490 pub post_link_objects: Vec<String>, // ... unconditionally
491 pub post_link_objects_crt: Vec<String>, // ... when linking with a bundled crt
492 /// Linker arguments that are unconditionally passed *after* any
493 /// user-defined libraries.
494 pub post_link_args: LinkArgs,
496 /// Environment variables to be set before invoking the linker.
497 pub link_env: Vec<(String, String)>,
499 /// Extra arguments to pass to the external assembler (when used)
500 pub asm_args: Vec<String>,
502 /// Default CPU to pass to LLVM. Corresponds to `llc -mcpu=$cpu`. Defaults
505 /// Default target features to pass to LLVM. These features will *always* be
506 /// passed, and cannot be disabled even via `-C`. Corresponds to `llc
507 /// -mattr=$features`.
508 pub features: String,
509 /// Whether dynamic linking is available on this target. Defaults to false.
510 pub dynamic_linking: bool,
511 /// If dynamic linking is available, whether only cdylibs are supported.
512 pub only_cdylib: bool,
513 /// Whether executables are available on this target. iOS, for example, only allows static
514 /// libraries. Defaults to false.
515 pub executables: bool,
516 /// Relocation model to use in object file. Corresponds to `llc
517 /// -relocation-model=$relocation_model`. Defaults to "pic".
518 pub relocation_model: String,
519 /// Code model to use. Corresponds to `llc -code-model=$code_model`.
520 pub code_model: Option<String>,
521 /// TLS model to use. Options are "global-dynamic" (default), "local-dynamic", "initial-exec"
522 /// and "local-exec". This is similar to the -ftls-model option in GCC/Clang.
523 pub tls_model: String,
524 /// Do not emit code that uses the "red zone", if the ABI has one. Defaults to false.
525 pub disable_redzone: bool,
526 /// Eliminate frame pointers from stack frames if possible. Defaults to true.
527 pub eliminate_frame_pointer: bool,
528 /// Emit each function in its own section. Defaults to true.
529 pub function_sections: bool,
530 /// String to prepend to the name of every dynamic library. Defaults to "lib".
531 pub dll_prefix: String,
532 /// String to append to the name of every dynamic library. Defaults to ".so".
533 pub dll_suffix: String,
534 /// String to append to the name of every executable.
535 pub exe_suffix: String,
536 /// String to prepend to the name of every static library. Defaults to "lib".
537 pub staticlib_prefix: String,
538 /// String to append to the name of every static library. Defaults to ".a".
539 pub staticlib_suffix: String,
540 /// OS family to use for conditional compilation. Valid options: "unix", "windows".
541 pub target_family: Option<String>,
542 /// Whether the target toolchain's ABI supports returning small structs as an integer.
543 pub abi_return_struct_as_int: bool,
544 /// Whether the target toolchain is like macOS's. Only useful for compiling against iOS/macOS,
545 /// in particular running dsymutil and some other stuff like `-dead_strip`. Defaults to false.
546 pub is_like_osx: bool,
547 /// Whether the target toolchain is like Solaris's.
548 /// Only useful for compiling against Illumos/Solaris,
549 /// as they have a different set of linker flags. Defaults to false.
550 pub is_like_solaris: bool,
551 /// Whether the target toolchain is like Windows'. Only useful for compiling against Windows,
552 /// only really used for figuring out how to find libraries, since Windows uses its own
553 /// library naming convention. Defaults to false.
554 pub is_like_windows: bool,
555 pub is_like_msvc: bool,
556 /// Whether the target toolchain is like Android's. Only useful for compiling against Android.
557 /// Defaults to false.
558 pub is_like_android: bool,
559 /// Whether the target toolchain is like Emscripten's. Only useful for compiling with
560 /// Emscripten toolchain.
561 /// Defaults to false.
562 pub is_like_emscripten: bool,
563 /// Whether the target toolchain is like Fuchsia's.
564 pub is_like_fuchsia: bool,
565 /// Whether the linker support GNU-like arguments such as -O. Defaults to false.
566 pub linker_is_gnu: bool,
567 /// The MinGW toolchain has a known issue that prevents it from correctly
568 /// handling COFF object files with more than 2<sup>15</sup> sections. Since each weak
569 /// symbol needs its own COMDAT section, weak linkage implies a large
570 /// number sections that easily exceeds the given limit for larger
571 /// codebases. Consequently we want a way to disallow weak linkage on some
573 pub allows_weak_linkage: bool,
574 /// Whether the linker support rpaths or not. Defaults to false.
576 /// Whether to disable linking to the default libraries, typically corresponds
577 /// to `-nodefaultlibs`. Defaults to true.
578 pub no_default_libraries: bool,
579 /// Dynamically linked executables can be compiled as position independent
580 /// if the default relocation model of position independent code is not
581 /// changed. This is a requirement to take advantage of ASLR, as otherwise
582 /// the functions in the executable are not randomized and can be used
583 /// during an exploit of a vulnerability in any code.
584 pub position_independent_executables: bool,
585 /// Determines if the target always requires using the PLT for indirect
586 /// library calls or not. This controls the default value of the `-Z plt` flag.
588 /// Either partial, full, or off. Full RELRO makes the dynamic linker
589 /// resolve all symbols at startup and marks the GOT read-only before
590 /// starting the program, preventing overwriting the GOT.
591 pub relro_level: RelroLevel,
592 /// Format that archives should be emitted in. This affects whether we use
593 /// LLVM to assemble an archive or fall back to the system linker, and
594 /// currently only "gnu" is used to fall into LLVM. Unknown strings cause
595 /// the system linker to be used.
596 pub archive_format: String,
597 /// Is asm!() allowed? Defaults to true.
599 /// Whether the target uses a custom unwind resumption routine.
600 /// By default LLVM lowers `resume` instructions into calls to `_Unwind_Resume`
601 /// defined in libgcc. If this option is enabled, the target must provide
602 /// `eh_unwind_resume` lang item.
603 pub custom_unwind_resume: bool,
605 /// Flag indicating whether ELF TLS (e.g. #[thread_local]) is available for
607 pub has_elf_tls: bool,
608 // This is mainly for easy compatibility with emscripten.
609 // If we give emcc .o files that are actually .bc files it
611 pub obj_is_bitcode: bool,
613 // LLVM can't produce object files for this target. Instead, we'll make LLVM
614 // emit assembly and then use `gcc` to turn that assembly into an object
616 pub no_integrated_as: bool,
618 /// Don't use this field; instead use the `.min_atomic_width()` method.
619 pub min_atomic_width: Option<u64>,
621 /// Don't use this field; instead use the `.max_atomic_width()` method.
622 pub max_atomic_width: Option<u64>,
624 /// Whether the target supports atomic CAS operations natively
625 pub atomic_cas: bool,
627 /// Panic strategy: "unwind" or "abort"
628 pub panic_strategy: PanicStrategy,
630 /// A blacklist of ABIs unsupported by the current target. Note that generic
631 /// ABIs are considered to be supported on all platforms and cannot be blacklisted.
632 pub abi_blacklist: Vec<Abi>,
634 /// Whether or not linking dylibs to a static CRT is allowed.
635 pub crt_static_allows_dylibs: bool,
636 /// Whether or not the CRT is statically linked by default.
637 pub crt_static_default: bool,
638 /// Whether or not crt-static is respected by the compiler (or is a no-op).
639 pub crt_static_respected: bool,
641 /// Whether or not stack probes (__rust_probestack) are enabled
642 pub stack_probes: bool,
644 /// The minimum alignment for global symbols.
645 pub min_global_align: Option<u64>,
647 /// Default number of codegen units to use in debug mode
648 pub default_codegen_units: Option<u64>,
650 /// Whether to generate trap instructions in places where optimization would
651 /// otherwise produce control flow that falls through into unrelated memory.
652 pub trap_unreachable: bool,
654 /// This target requires everything to be compiled with LTO to emit a final
655 /// executable, aka there is no native linker for this target.
656 pub requires_lto: bool,
658 /// This target has no support for threads.
659 pub singlethread: bool,
661 /// Whether library functions call lowering/optimization is disabled in LLVM
662 /// for this target unconditionally.
663 pub no_builtins: bool,
665 /// Whether to lower 128-bit operations to compiler_builtins calls. Use if
666 /// your backend only supports 64-bit and smaller math.
667 pub i128_lowering: bool,
669 /// The codegen backend to use for this target, typically "llvm"
670 pub codegen_backend: String,
672 /// The default visibility for symbols in this target should be "hidden"
673 /// rather than "default"
674 pub default_hidden_visibility: bool,
676 /// Whether or not bitcode is embedded in object files
677 pub embed_bitcode: bool,
679 /// Whether a .debug_gdb_scripts section will be added to the output object file
680 pub emit_debug_gdb_scripts: bool,
682 /// Whether or not to unconditionally `uwtable` attributes on functions,
683 /// typically because the platform needs to unwind for things like stack
685 pub requires_uwtable: bool,
687 /// Whether or not SIMD types are passed by reference in the Rust ABI,
688 /// typically required if a target can be compiled with a mixed set of
689 /// target features. This is `true` by default, and `false` for targets like
690 /// wasm32 where the whole program either has simd or not.
691 pub simd_types_indirect: bool,
693 /// If set, have the linker export exactly these symbols, instead of using
694 /// the usual logic to figure this out from the crate itself.
695 pub override_export_symbols: Option<Vec<String>>
698 impl Default for TargetOptions {
699 /// Create a set of "sane defaults" for any target. This is still
700 /// incomplete, and if used for compilation, will certainly not work.
701 fn default() -> TargetOptions {
704 linker: option_env!("CFG_DEFAULT_LINKER").map(|s| s.to_string()),
705 lld_flavor: LldFlavor::Ld,
706 pre_link_args: LinkArgs::new(),
707 pre_link_args_crt: LinkArgs::new(),
708 post_link_args: LinkArgs::new(),
709 asm_args: Vec::new(),
710 cpu: "generic".to_string(),
711 features: String::new(),
712 dynamic_linking: false,
715 relocation_model: "pic".to_string(),
717 tls_model: "global-dynamic".to_string(),
718 disable_redzone: false,
719 eliminate_frame_pointer: true,
720 function_sections: true,
721 dll_prefix: "lib".to_string(),
722 dll_suffix: ".so".to_string(),
723 exe_suffix: String::new(),
724 staticlib_prefix: "lib".to_string(),
725 staticlib_suffix: ".a".to_string(),
727 abi_return_struct_as_int: false,
729 is_like_solaris: false,
730 is_like_windows: false,
731 is_like_android: false,
732 is_like_emscripten: false,
734 is_like_fuchsia: false,
735 linker_is_gnu: false,
736 allows_weak_linkage: true,
738 no_default_libraries: true,
739 position_independent_executables: false,
741 relro_level: RelroLevel::None,
742 pre_link_objects_exe: Vec::new(),
743 pre_link_objects_exe_crt: Vec::new(),
744 pre_link_objects_dll: Vec::new(),
745 post_link_objects: Vec::new(),
746 post_link_objects_crt: Vec::new(),
747 late_link_args: LinkArgs::new(),
748 link_env: Vec::new(),
749 archive_format: "gnu".to_string(),
750 custom_unwind_resume: false,
753 obj_is_bitcode: false,
754 no_integrated_as: false,
755 min_atomic_width: None,
756 max_atomic_width: None,
758 panic_strategy: PanicStrategy::Unwind,
759 abi_blacklist: vec![],
760 crt_static_allows_dylibs: false,
761 crt_static_default: false,
762 crt_static_respected: false,
764 min_global_align: None,
765 default_codegen_units: None,
766 trap_unreachable: true,
770 i128_lowering: false,
771 codegen_backend: "llvm".to_string(),
772 default_hidden_visibility: false,
773 embed_bitcode: false,
774 emit_debug_gdb_scripts: true,
775 requires_uwtable: false,
776 simd_types_indirect: true,
777 override_export_symbols: None,
783 /// Given a function ABI, turn it into the correct ABI for this target.
784 pub fn adjust_abi(&self, abi: Abi) -> Abi {
787 if self.options.is_like_windows && self.arch == "x86" {
793 // These ABI kinds are ignored on non-x86 Windows targets.
794 // See https://docs.microsoft.com/en-us/cpp/cpp/argument-passing-and-naming-conventions
795 // and the individual pages for __stdcall et al.
796 Abi::Stdcall | Abi::Fastcall | Abi::Vectorcall | Abi::Thiscall => {
797 if self.options.is_like_windows && self.arch != "x86" {
807 /// Minimum integer size in bits that this target can perform atomic
809 pub fn min_atomic_width(&self) -> u64 {
810 self.options.min_atomic_width.unwrap_or(8)
813 /// Maximum integer size in bits that this target can perform atomic
815 pub fn max_atomic_width(&self) -> u64 {
816 self.options.max_atomic_width.unwrap_or_else(|| self.target_pointer_width.parse().unwrap())
819 pub fn is_abi_supported(&self, abi: Abi) -> bool {
820 abi.generic() || !self.options.abi_blacklist.contains(&abi)
823 /// Load a target descriptor from a JSON object.
824 pub fn from_json(obj: Json) -> TargetResult {
825 // While ugly, this code must remain this way to retain
826 // compatibility with existing JSON fields and the internal
827 // expected naming of the Target and TargetOptions structs.
828 // To ensure compatibility is retained, the built-in targets
829 // are round-tripped through this code to catch cases where
830 // the JSON parser is not updated to match the structs.
832 let get_req_field = |name: &str| {
834 .map(|s| s.as_string())
835 .and_then(|os| os.map(|s| s.to_string()))
836 .ok_or_else(|| format!("Field {} in target specification is required", name))
839 let get_opt_field = |name: &str, default: &str| {
840 obj.find(name).and_then(|s| s.as_string())
841 .map(|s| s.to_string())
842 .unwrap_or_else(|| default.to_string())
845 let mut base = Target {
846 llvm_target: get_req_field("llvm-target")?,
847 target_endian: get_req_field("target-endian")?,
848 target_pointer_width: get_req_field("target-pointer-width")?,
849 target_c_int_width: get_req_field("target-c-int-width")?,
850 data_layout: get_req_field("data-layout")?,
851 arch: get_req_field("arch")?,
852 target_os: get_req_field("os")?,
853 target_env: get_opt_field("env", ""),
854 target_vendor: get_opt_field("vendor", "unknown"),
855 linker_flavor: LinkerFlavor::from_str(&*get_req_field("linker-flavor")?)
857 format!("linker flavor must be {}", LinkerFlavor::one_of())
859 options: Default::default(),
863 ($key_name:ident) => ( {
864 let name = (stringify!($key_name)).replace("_", "-");
865 obj.find(&name[..]).map(|o| o.as_string()
866 .map(|s| base.options.$key_name = s.to_string()));
868 ($key_name:ident, bool) => ( {
869 let name = (stringify!($key_name)).replace("_", "-");
871 .map(|o| o.as_boolean()
872 .map(|s| base.options.$key_name = s));
874 ($key_name:ident, Option<u64>) => ( {
875 let name = (stringify!($key_name)).replace("_", "-");
878 .map(|s| base.options.$key_name = Some(s)));
880 ($key_name:ident, PanicStrategy) => ( {
881 let name = (stringify!($key_name)).replace("_", "-");
882 obj.find(&name[..]).and_then(|o| o.as_string().and_then(|s| {
884 "unwind" => base.options.$key_name = PanicStrategy::Unwind,
885 "abort" => base.options.$key_name = PanicStrategy::Abort,
886 _ => return Some(Err(format!("'{}' is not a valid value for \
887 panic-strategy. Use 'unwind' or 'abort'.",
891 })).unwrap_or(Ok(()))
893 ($key_name:ident, RelroLevel) => ( {
894 let name = (stringify!($key_name)).replace("_", "-");
895 obj.find(&name[..]).and_then(|o| o.as_string().and_then(|s| {
896 match s.parse::<RelroLevel>() {
897 Ok(level) => base.options.$key_name = level,
898 _ => return Some(Err(format!("'{}' is not a valid value for \
899 relro-level. Use 'full', 'partial, or 'off'.",
903 })).unwrap_or(Ok(()))
905 ($key_name:ident, list) => ( {
906 let name = (stringify!($key_name)).replace("_", "-");
907 obj.find(&name[..]).map(|o| o.as_array()
908 .map(|v| base.options.$key_name = v.iter()
909 .map(|a| a.as_string().unwrap().to_string()).collect()
913 ($key_name:ident, opt_list) => ( {
914 let name = (stringify!($key_name)).replace("_", "-");
915 obj.find(&name[..]).map(|o| o.as_array()
916 .map(|v| base.options.$key_name = Some(v.iter()
917 .map(|a| a.as_string().unwrap().to_string()).collect())
921 ($key_name:ident, optional) => ( {
922 let name = (stringify!($key_name)).replace("_", "-");
923 if let Some(o) = obj.find(&name[..]) {
924 base.options.$key_name = o
926 .map(|s| s.to_string() );
929 ($key_name:ident, LldFlavor) => ( {
930 let name = (stringify!($key_name)).replace("_", "-");
931 obj.find(&name[..]).and_then(|o| o.as_string().and_then(|s| {
932 if let Some(flavor) = LldFlavor::from_str(&s) {
933 base.options.$key_name = flavor;
935 return Some(Err(format!(
936 "'{}' is not a valid value for lld-flavor. \
937 Use 'darwin', 'gnu', 'link' or 'wasm.",
941 })).unwrap_or(Ok(()))
943 ($key_name:ident, LinkerFlavor) => ( {
944 let name = (stringify!($key_name)).replace("_", "-");
945 obj.find(&name[..]).and_then(|o| o.as_string().map(|s| {
946 LinkerFlavor::from_str(&s).ok_or_else(|| {
947 Err(format!("'{}' is not a valid value for linker-flavor. \
948 Use 'em', 'gcc', 'ld' or 'msvc.", s))
950 })).unwrap_or(Ok(()))
952 ($key_name:ident, link_args) => ( {
953 let name = (stringify!($key_name)).replace("_", "-");
954 if let Some(val) = obj.find(&name[..]) {
955 let obj = val.as_object().ok_or_else(|| format!("{}: expected a \
956 JSON object with fields per linker-flavor.", name))?;
957 let mut args = LinkArgs::new();
959 let flavor = LinkerFlavor::from_str(&k).ok_or_else(|| {
960 format!("{}: '{}' is not a valid value for linker-flavor. \
961 Use 'em', 'gcc', 'ld' or 'msvc'", name, k)
964 let v = v.as_array().ok_or_else(||
965 format!("{}.{}: expected a JSON array", name, k)
966 )?.iter().enumerate()
968 let s = s.as_string().ok_or_else(||
969 format!("{}.{}[{}]: expected a JSON string", name, k, i))?;
972 .collect::<Result<Vec<_>, String>>()?;
974 args.insert(flavor, v);
976 base.options.$key_name = args;
979 ($key_name:ident, env) => ( {
980 let name = (stringify!($key_name)).replace("_", "-");
981 if let Some(a) = obj.find(&name[..]).and_then(|o| o.as_array()) {
983 if let Some(s) = o.as_string() {
984 let p = s.split('=').collect::<Vec<_>>();
986 let k = p[0].to_string();
987 let v = p[1].to_string();
988 base.options.$key_name.push((k, v));
996 key!(is_builtin, bool);
997 key!(linker, optional);
998 try!(key!(lld_flavor, LldFlavor));
999 key!(pre_link_args, link_args);
1000 key!(pre_link_args_crt, link_args);
1001 key!(pre_link_objects_exe, list);
1002 key!(pre_link_objects_exe_crt, list);
1003 key!(pre_link_objects_dll, list);
1004 key!(late_link_args, link_args);
1005 key!(post_link_objects, list);
1006 key!(post_link_objects_crt, list);
1007 key!(post_link_args, link_args);
1008 key!(link_env, env);
1009 key!(asm_args, list);
1012 key!(dynamic_linking, bool);
1013 key!(only_cdylib, bool);
1014 key!(executables, bool);
1015 key!(relocation_model);
1016 key!(code_model, optional);
1018 key!(disable_redzone, bool);
1019 key!(eliminate_frame_pointer, bool);
1020 key!(function_sections, bool);
1024 key!(staticlib_prefix);
1025 key!(staticlib_suffix);
1026 key!(target_family, optional);
1027 key!(abi_return_struct_as_int, bool);
1028 key!(is_like_osx, bool);
1029 key!(is_like_solaris, bool);
1030 key!(is_like_windows, bool);
1031 key!(is_like_msvc, bool);
1032 key!(is_like_emscripten, bool);
1033 key!(is_like_android, bool);
1034 key!(is_like_fuchsia, bool);
1035 key!(linker_is_gnu, bool);
1036 key!(allows_weak_linkage, bool);
1037 key!(has_rpath, bool);
1038 key!(no_default_libraries, bool);
1039 key!(position_independent_executables, bool);
1040 key!(needs_plt, bool);
1041 try!(key!(relro_level, RelroLevel));
1042 key!(archive_format);
1043 key!(allow_asm, bool);
1044 key!(custom_unwind_resume, bool);
1045 key!(has_elf_tls, bool);
1046 key!(obj_is_bitcode, bool);
1047 key!(no_integrated_as, bool);
1048 key!(max_atomic_width, Option<u64>);
1049 key!(min_atomic_width, Option<u64>);
1050 key!(atomic_cas, bool);
1051 try!(key!(panic_strategy, PanicStrategy));
1052 key!(crt_static_allows_dylibs, bool);
1053 key!(crt_static_default, bool);
1054 key!(crt_static_respected, bool);
1055 key!(stack_probes, bool);
1056 key!(min_global_align, Option<u64>);
1057 key!(default_codegen_units, Option<u64>);
1058 key!(trap_unreachable, bool);
1059 key!(requires_lto, bool);
1060 key!(singlethread, bool);
1061 key!(no_builtins, bool);
1062 key!(codegen_backend);
1063 key!(default_hidden_visibility, bool);
1064 key!(embed_bitcode, bool);
1065 key!(emit_debug_gdb_scripts, bool);
1066 key!(requires_uwtable, bool);
1067 key!(simd_types_indirect, bool);
1068 key!(override_export_symbols, opt_list);
1070 if let Some(array) = obj.find("abi-blacklist").and_then(Json::as_array) {
1071 for name in array.iter().filter_map(|abi| abi.as_string()) {
1072 match lookup_abi(name) {
1075 return Err(format!("The ABI \"{}\" is considered to be supported on \
1076 all targets and cannot be blacklisted", abi))
1079 base.options.abi_blacklist.push(abi)
1081 None => return Err(format!("Unknown ABI \"{}\" in target specification", name))
1089 /// Search RUST_TARGET_PATH for a JSON file specifying the given target
1090 /// triple. Note that it could also just be a bare filename already, so also
1091 /// check for that. If one of the hardcoded targets we know about, just
1092 /// return it directly.
1094 /// The error string could come from any of the APIs called, including
1095 /// filesystem access and JSON decoding.
1096 pub fn search(target_triple: &TargetTriple) -> Result<Target, String> {
1099 use serialize::json;
1101 fn load_file(path: &Path) -> Result<Target, String> {
1102 let contents = fs::read(path).map_err(|e| e.to_string())?;
1103 let obj = json::from_reader(&mut &contents[..])
1104 .map_err(|e| e.to_string())?;
1105 Target::from_json(obj)
1108 match *target_triple {
1109 TargetTriple::TargetTriple(ref target_triple) => {
1110 // check if triple is in list of supported targets
1111 if let Ok(t) = load_specific(target_triple) {
1115 // search for a file named `target_triple`.json in RUST_TARGET_PATH
1117 let mut target = target_triple.to_string();
1118 target.push_str(".json");
1119 PathBuf::from(target)
1122 let target_path = env::var_os("RUST_TARGET_PATH").unwrap_or_default();
1124 // FIXME 16351: add a sane default search path?
1126 for dir in env::split_paths(&target_path) {
1127 let p = dir.join(&path);
1129 return load_file(&p);
1132 Err(format!("Could not find specification for target {:?}", target_triple))
1134 TargetTriple::TargetPath(ref target_path) => {
1135 if target_path.is_file() {
1136 return load_file(&target_path);
1138 Err(format!("Target path {:?} is not a valid file", target_path))
1144 impl ToJson for Target {
1145 fn to_json(&self) -> Json {
1146 let mut d = BTreeMap::new();
1147 let default: TargetOptions = Default::default();
1149 macro_rules! target_val {
1150 ($attr:ident) => ( {
1151 let name = (stringify!($attr)).replace("_", "-");
1152 d.insert(name, self.$attr.to_json());
1154 ($attr:ident, $key_name:expr) => ( {
1155 let name = $key_name;
1156 d.insert(name.to_string(), self.$attr.to_json());
1160 macro_rules! target_option_val {
1161 ($attr:ident) => ( {
1162 let name = (stringify!($attr)).replace("_", "-");
1163 if default.$attr != self.options.$attr {
1164 d.insert(name, self.options.$attr.to_json());
1167 ($attr:ident, $key_name:expr) => ( {
1168 let name = $key_name;
1169 if default.$attr != self.options.$attr {
1170 d.insert(name.to_string(), self.options.$attr.to_json());
1173 (link_args - $attr:ident) => ( {
1174 let name = (stringify!($attr)).replace("_", "-");
1175 if default.$attr != self.options.$attr {
1176 let obj = self.options.$attr
1178 .map(|(k, v)| (k.desc().to_owned(), v.clone()))
1179 .collect::<BTreeMap<_, _>>();
1180 d.insert(name, obj.to_json());
1183 (env - $attr:ident) => ( {
1184 let name = (stringify!($attr)).replace("_", "-");
1185 if default.$attr != self.options.$attr {
1186 let obj = self.options.$attr
1188 .map(|&(ref k, ref v)| k.clone() + "=" + &v)
1189 .collect::<Vec<_>>();
1190 d.insert(name, obj.to_json());
1196 target_val!(llvm_target);
1197 target_val!(target_endian);
1198 target_val!(target_pointer_width);
1199 target_val!(target_c_int_width);
1201 target_val!(target_os, "os");
1202 target_val!(target_env, "env");
1203 target_val!(target_vendor, "vendor");
1204 target_val!(data_layout);
1205 target_val!(linker_flavor);
1207 target_option_val!(is_builtin);
1208 target_option_val!(linker);
1209 target_option_val!(lld_flavor);
1210 target_option_val!(link_args - pre_link_args);
1211 target_option_val!(link_args - pre_link_args_crt);
1212 target_option_val!(pre_link_objects_exe);
1213 target_option_val!(pre_link_objects_exe_crt);
1214 target_option_val!(pre_link_objects_dll);
1215 target_option_val!(link_args - late_link_args);
1216 target_option_val!(post_link_objects);
1217 target_option_val!(post_link_objects_crt);
1218 target_option_val!(link_args - post_link_args);
1219 target_option_val!(env - link_env);
1220 target_option_val!(asm_args);
1221 target_option_val!(cpu);
1222 target_option_val!(features);
1223 target_option_val!(dynamic_linking);
1224 target_option_val!(only_cdylib);
1225 target_option_val!(executables);
1226 target_option_val!(relocation_model);
1227 target_option_val!(code_model);
1228 target_option_val!(tls_model);
1229 target_option_val!(disable_redzone);
1230 target_option_val!(eliminate_frame_pointer);
1231 target_option_val!(function_sections);
1232 target_option_val!(dll_prefix);
1233 target_option_val!(dll_suffix);
1234 target_option_val!(exe_suffix);
1235 target_option_val!(staticlib_prefix);
1236 target_option_val!(staticlib_suffix);
1237 target_option_val!(target_family);
1238 target_option_val!(abi_return_struct_as_int);
1239 target_option_val!(is_like_osx);
1240 target_option_val!(is_like_solaris);
1241 target_option_val!(is_like_windows);
1242 target_option_val!(is_like_msvc);
1243 target_option_val!(is_like_emscripten);
1244 target_option_val!(is_like_android);
1245 target_option_val!(is_like_fuchsia);
1246 target_option_val!(linker_is_gnu);
1247 target_option_val!(allows_weak_linkage);
1248 target_option_val!(has_rpath);
1249 target_option_val!(no_default_libraries);
1250 target_option_val!(position_independent_executables);
1251 target_option_val!(needs_plt);
1252 target_option_val!(relro_level);
1253 target_option_val!(archive_format);
1254 target_option_val!(allow_asm);
1255 target_option_val!(custom_unwind_resume);
1256 target_option_val!(has_elf_tls);
1257 target_option_val!(obj_is_bitcode);
1258 target_option_val!(no_integrated_as);
1259 target_option_val!(min_atomic_width);
1260 target_option_val!(max_atomic_width);
1261 target_option_val!(atomic_cas);
1262 target_option_val!(panic_strategy);
1263 target_option_val!(crt_static_allows_dylibs);
1264 target_option_val!(crt_static_default);
1265 target_option_val!(crt_static_respected);
1266 target_option_val!(stack_probes);
1267 target_option_val!(min_global_align);
1268 target_option_val!(default_codegen_units);
1269 target_option_val!(trap_unreachable);
1270 target_option_val!(requires_lto);
1271 target_option_val!(singlethread);
1272 target_option_val!(no_builtins);
1273 target_option_val!(codegen_backend);
1274 target_option_val!(default_hidden_visibility);
1275 target_option_val!(embed_bitcode);
1276 target_option_val!(emit_debug_gdb_scripts);
1277 target_option_val!(requires_uwtable);
1278 target_option_val!(simd_types_indirect);
1279 target_option_val!(override_export_symbols);
1281 if default.abi_blacklist != self.options.abi_blacklist {
1282 d.insert("abi-blacklist".to_string(), self.options.abi_blacklist.iter()
1283 .map(|&name| Abi::name(name).to_json())
1284 .collect::<Vec<_>>().to_json());
1291 /// Either a target triple string or a path to a JSON file.
1292 #[derive(PartialEq, Clone, Debug, Hash, RustcEncodable, RustcDecodable)]
1293 pub enum TargetTriple {
1294 TargetTriple(String),
1295 TargetPath(PathBuf),
1299 /// Creates a target triple from the passed target triple string.
1300 pub fn from_triple(triple: &str) -> Self {
1301 TargetTriple::TargetTriple(triple.to_string())
1304 /// Creates a target triple from the passed target path.
1305 pub fn from_path(path: &Path) -> Result<Self, io::Error> {
1306 let canonicalized_path = path.canonicalize()?;
1307 Ok(TargetTriple::TargetPath(canonicalized_path))
1310 /// Returns a string triple for this target.
1312 /// If this target is a path, the file name (without extension) is returned.
1313 pub fn triple(&self) -> &str {
1315 TargetTriple::TargetTriple(ref triple) => triple,
1316 TargetTriple::TargetPath(ref path) => {
1317 path.file_stem().expect("target path must not be empty").to_str()
1318 .expect("target path must be valid unicode")
1323 /// Returns an extended string triple for this target.
1325 /// If this target is a path, a hash of the path is appended to the triple returned
1327 pub fn debug_triple(&self) -> String {
1328 use std::hash::{Hash, Hasher};
1329 use std::collections::hash_map::DefaultHasher;
1331 let triple = self.triple();
1332 if let TargetTriple::TargetPath(ref path) = *self {
1333 let mut hasher = DefaultHasher::new();
1334 path.hash(&mut hasher);
1335 let hash = hasher.finish();
1336 format!("{}-{}", triple, hash)
1343 impl fmt::Display for TargetTriple {
1344 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1345 write!(f, "{}", self.debug_triple())