// Copyright 2014-2015 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. //! [Flexible target specification.](https://github.com/rust-lang/rfcs/pull/131) //! //! Rust targets a wide variety of usecases, and in the interest of flexibility, //! allows new target triples to be defined in configuration files. Most users //! will not need to care about these, but this is invaluable when porting Rust //! to a new platform, and allows for an unprecedented level of control over how //! the compiler works. //! //! # Using custom targets //! //! A target triple, as passed via `rustc --target=TRIPLE`, will first be //! compared against the list of built-in targets. This is to ease distributing //! rustc (no need for configuration files) and also to hold these built-in //! targets as immutable and sacred. If `TRIPLE` is not one of the built-in //! targets, rustc will check if a file named `TRIPLE` exists. If it does, it //! will be loaded as the target configuration. If the file does not exist, //! rustc will search each directory in the environment variable //! `RUST_TARGET_PATH` for a file named `TRIPLE.json`. The first one found will //! be loaded. If no file is found in any of those directories, a fatal error //! will be given. `RUST_TARGET_PATH` includes `/etc/rustc` as its last entry, //! to be searched by default. //! //! Projects defining their own targets should use //! `--target=path/to/my-awesome-platform.json` instead of adding to //! `RUST_TARGET_PATH`. //! //! # Defining a new target //! //! Targets are defined using [JSON](http://json.org/). The `Target` struct in //! this module defines the format the JSON file should take, though each //! underscore in the field names should be replaced with a hyphen (`-`) in the //! JSON file. Some fields are required in every target specification, such as //! `data-layout`, `llvm-target`, `target-endian`, `target-pointer-width`, and //! `arch`. In general, options passed to rustc with `-C` override the target's //! settings, though `target-feature` and `link-args` will *add* to the list //! specified by the target, rather than replace. use serialize::json::Json; use std::default::Default; use std::io::prelude::*; use syntax::abi; mod android_base; mod apple_base; mod apple_ios_base; mod bitrig_base; mod dragonfly_base; mod freebsd_base; mod linux_base; mod openbsd_base; mod netbsd_base; mod windows_base; mod windows_msvc_base; /// Everything `rustc` knows about how to compile for a specific target. /// /// Every field here must be specified, and has no default value. #[derive(Clone, Debug)] pub struct Target { /// Target triple to pass to LLVM. pub llvm_target: String, /// String to use as the `target_endian` `cfg` variable. pub target_endian: String, /// String to use as the `target_pointer_width` `cfg` variable. pub target_pointer_width: String, /// OS name to use for conditional compilation. pub target_os: String, /// Environment name to use for conditional compilation. pub target_env: String, /// Vendor name to use for conditional compilation. pub target_vendor: String, /// Architecture to use for ABI considerations. Valid options: "x86", "x86_64", "arm", /// "aarch64", "mips", "powerpc", "powerpc64" and "powerpc64le". "mips" includes "mipsel". pub arch: String, /// Optional settings with defaults. pub options: TargetOptions, } /// Optional aspects of a target specification. /// /// This has an implementation of `Default`, see each field for what the default is. In general, /// these try to take "minimal defaults" that don't assume anything about the runtime they run in. #[derive(Clone, Debug)] pub struct TargetOptions { /// [Data layout](http://llvm.org/docs/LangRef.html#data-layout) to pass to LLVM. pub data_layout: Option, /// Linker to invoke. Defaults to "cc". pub linker: String, /// Archive utility to use when managing archives. Defaults to "ar". pub ar: String, /// Linker arguments that are unconditionally passed *before* any /// user-defined libraries. pub pre_link_args: Vec, /// Objects to link before all others, always found within the /// sysroot folder. pub pre_link_objects_exe: Vec, // ... when linking an executable pub pre_link_objects_dll: Vec, // ... when linking a dylib /// Linker arguments that are unconditionally passed after any /// user-defined but before post_link_objects. Standard platform /// libraries that should be always be linked to, usually go here. pub late_link_args: Vec, /// Objects to link after all others, always found within the /// sysroot folder. pub post_link_objects: Vec, /// Linker arguments that are unconditionally passed *after* any /// user-defined libraries. pub post_link_args: Vec, /// Default CPU to pass to LLVM. Corresponds to `llc -mcpu=$cpu`. Defaults /// to "default". pub cpu: String, /// Default target features to pass to LLVM. These features will *always* be /// passed, and cannot be disabled even via `-C`. Corresponds to `llc /// -mattr=$features`. pub features: String, /// Whether dynamic linking is available on this target. Defaults to false. pub dynamic_linking: bool, /// Whether executables are available on this target. iOS, for example, only allows static /// libraries. Defaults to false. pub executables: bool, /// Relocation model to use in object file. Corresponds to `llc /// -relocation-model=$relocation_model`. Defaults to "pic". pub relocation_model: String, /// Code model to use. Corresponds to `llc -code-model=$code_model`. Defaults to "default". pub code_model: String, /// Do not emit code that uses the "red zone", if the ABI has one. Defaults to false. pub disable_redzone: bool, /// Eliminate frame pointers from stack frames if possible. Defaults to true. pub eliminate_frame_pointer: bool, /// Emit each function in its own section. Defaults to true. pub function_sections: bool, /// String to prepend to the name of every dynamic library. Defaults to "lib". pub dll_prefix: String, /// String to append to the name of every dynamic library. Defaults to ".so". pub dll_suffix: String, /// String to append to the name of every executable. pub exe_suffix: String, /// String to prepend to the name of every static library. Defaults to "lib". pub staticlib_prefix: String, /// String to append to the name of every static library. Defaults to ".a". pub staticlib_suffix: String, /// OS family to use for conditional compilation. Valid options: "unix", "windows". pub target_family: Option, /// Whether the target toolchain is like OSX's. Only useful for compiling against iOS/OS X, in /// particular running dsymutil and some other stuff like `-dead_strip`. Defaults to false. pub is_like_osx: bool, /// Whether the target toolchain is like Windows'. Only useful for compiling against Windows, /// only really used for figuring out how to find libraries, since Windows uses its own /// library naming convention. Defaults to false. pub is_like_windows: bool, pub is_like_msvc: bool, /// Whether the target toolchain is like Android's. Only useful for compiling against Android. /// Defaults to false. pub is_like_android: bool, /// Whether the linker support GNU-like arguments such as -O. Defaults to false. pub linker_is_gnu: bool, /// Whether the linker support rpaths or not. Defaults to false. pub has_rpath: bool, /// Whether to disable linking to compiler-rt. Defaults to false, as LLVM /// will emit references to the functions that compiler-rt provides. pub no_compiler_rt: bool, /// Whether to disable linking to the default libraries, typically corresponds /// to `-nodefaultlibs`. Defaults to true. pub no_default_libraries: bool, /// Dynamically linked executables can be compiled as position independent /// if the default relocation model of position independent code is not /// changed. This is a requirement to take advantage of ASLR, as otherwise /// the functions in the executable are not randomized and can be used /// during an exploit of a vulnerability in any code. pub position_independent_executables: bool, /// Format that archives should be emitted in. This affects whether we use /// LLVM to assemble an archive or fall back to the system linker, and /// currently only "gnu" is used to fall into LLVM. Unknown strings cause /// the system linker to be used. pub archive_format: String, /// Is asm!() allowed? Defaults to true. pub allow_asm: bool, /// Whether the target uses a custom unwind resumption routine. /// By default LLVM lowers `resume` instructions into calls to `_Unwind_Resume` /// defined in libgcc. If this option is enabled, the target must provide /// `eh_unwind_resume` lang item. pub custom_unwind_resume: bool, /// Default crate for allocation symbols to link against pub lib_allocation_crate: String, pub exe_allocation_crate: String, /// Flag indicating whether ELF TLS (e.g. #[thread_local]) is available for /// this target. pub has_elf_tls: bool, } impl Default for TargetOptions { /// Create a set of "sane defaults" for any target. This is still /// incomplete, and if used for compilation, will certainly not work. fn default() -> TargetOptions { TargetOptions { data_layout: None, linker: option_env!("CFG_DEFAULT_LINKER").unwrap_or("cc").to_string(), ar: option_env!("CFG_DEFAULT_AR").unwrap_or("ar").to_string(), pre_link_args: Vec::new(), post_link_args: Vec::new(), cpu: "generic".to_string(), features: "".to_string(), dynamic_linking: false, executables: false, relocation_model: "pic".to_string(), code_model: "default".to_string(), disable_redzone: false, eliminate_frame_pointer: true, function_sections: true, dll_prefix: "lib".to_string(), dll_suffix: ".so".to_string(), exe_suffix: "".to_string(), staticlib_prefix: "lib".to_string(), staticlib_suffix: ".a".to_string(), target_family: None, is_like_osx: false, is_like_windows: false, is_like_android: false, is_like_msvc: false, linker_is_gnu: false, has_rpath: false, no_compiler_rt: false, no_default_libraries: true, position_independent_executables: false, pre_link_objects_exe: Vec::new(), pre_link_objects_dll: Vec::new(), post_link_objects: Vec::new(), late_link_args: Vec::new(), archive_format: String::new(), custom_unwind_resume: false, lib_allocation_crate: "alloc_system".to_string(), exe_allocation_crate: "alloc_system".to_string(), allow_asm: true, has_elf_tls: false, } } } impl Target { /// Given a function ABI, turn "System" into the correct ABI for this target. pub fn adjust_abi(&self, abi: abi::Abi) -> abi::Abi { match abi { abi::System => { if self.options.is_like_windows && self.arch == "x86" { abi::Stdcall } else { abi::C } }, abi => abi } } /// Load a target descriptor from a JSON object. pub fn from_json(obj: Json) -> Target { // this is 1. ugly, 2. error prone. let get_req_field = |name: &str| { match obj.find(name) .map(|s| s.as_string()) .and_then(|os| os.map(|s| s.to_string())) { Some(val) => val, None => { panic!("Field {} in target specification is required", name) } } }; let get_opt_field = |name: &str, default: &str| { obj.find(name).and_then(|s| s.as_string()) .map(|s| s.to_string()) .unwrap_or(default.to_string()) }; let mut base = Target { llvm_target: get_req_field("llvm-target"), target_endian: get_req_field("target-endian"), target_pointer_width: get_req_field("target-pointer-width"), arch: get_req_field("arch"), target_os: get_req_field("os"), target_env: get_opt_field("env", ""), target_vendor: get_opt_field("vendor", "unknown"), options: Default::default(), }; macro_rules! key { ($key_name:ident) => ( { let name = (stringify!($key_name)).replace("_", "-"); obj.find(&name[..]).map(|o| o.as_string() .map(|s| base.options.$key_name = s.to_string())); } ); ($key_name:ident, bool) => ( { let name = (stringify!($key_name)).replace("_", "-"); obj.find(&name[..]) .map(|o| o.as_boolean() .map(|s| base.options.$key_name = s)); } ); ($key_name:ident, list) => ( { let name = (stringify!($key_name)).replace("_", "-"); obj.find(&name[..]).map(|o| o.as_array() .map(|v| base.options.$key_name = v.iter() .map(|a| a.as_string().unwrap().to_string()).collect() ) ); } ); ($key_name:ident, optional) => ( { let name = (stringify!($key_name)).replace("_", "-"); if let Some(o) = obj.find(&name[..]) { base.options.$key_name = o .as_string() .map(|s| s.to_string() ); } } ); } key!(cpu); key!(ar); key!(linker); key!(relocation_model); key!(code_model); key!(dll_prefix); key!(dll_suffix); key!(exe_suffix); key!(staticlib_prefix); key!(staticlib_suffix); key!(features); key!(data_layout, optional); key!(dynamic_linking, bool); key!(executables, bool); key!(disable_redzone, bool); key!(eliminate_frame_pointer, bool); key!(function_sections, bool); key!(target_family, optional); key!(is_like_osx, bool); key!(is_like_windows, bool); key!(linker_is_gnu, bool); key!(has_rpath, bool); key!(no_compiler_rt, bool); key!(no_default_libraries, bool); key!(pre_link_args, list); key!(post_link_args, list); key!(archive_format); key!(allow_asm, bool); key!(custom_unwind_resume, bool); base } /// Search RUST_TARGET_PATH for a JSON file specifying the given target /// triple. Note that it could also just be a bare filename already, so also /// check for that. If one of the hardcoded targets we know about, just /// return it directly. /// /// The error string could come from any of the APIs called, including /// filesystem access and JSON decoding. pub fn search(target: &str) -> Result { use std::env; use std::ffi::OsString; use std::fs::File; use std::path::{Path, PathBuf}; use serialize::json; fn load_file(path: &Path) -> Result { let mut f = try!(File::open(path).map_err(|e| e.to_string())); let mut contents = Vec::new(); try!(f.read_to_end(&mut contents).map_err(|e| e.to_string())); let obj = try!(json::from_reader(&mut &contents[..]) .map_err(|e| e.to_string())); Ok(Target::from_json(obj)) } // this would use a match if stringify! were allowed in pattern position macro_rules! load_specific { ( $($name:ident),+ ) => ( { $(mod $name;)* let target = target.replace("-", "_"); if false { } $( else if target == stringify!($name) { let t = $name::target(); debug!("Got builtin target: {:?}", t); return Ok(t); } )* else if target == "x86_64-w64-mingw32" { let t = x86_64_pc_windows_gnu::target(); return Ok(t); } else if target == "i686-w64-mingw32" { let t = i686_pc_windows_gnu::target(); return Ok(t); } } ) } load_specific!( x86_64_unknown_linux_gnu, i686_unknown_linux_gnu, mips_unknown_linux_gnu, mipsel_unknown_linux_gnu, powerpc_unknown_linux_gnu, powerpc64_unknown_linux_gnu, powerpc64le_unknown_linux_gnu, arm_unknown_linux_gnueabi, arm_unknown_linux_gnueabihf, aarch64_unknown_linux_gnu, x86_64_unknown_linux_musl, i686_linux_android, arm_linux_androideabi, aarch64_linux_android, i686_unknown_freebsd, x86_64_unknown_freebsd, i686_unknown_dragonfly, x86_64_unknown_dragonfly, x86_64_unknown_bitrig, x86_64_unknown_openbsd, x86_64_unknown_netbsd, x86_64_rumprun_netbsd, x86_64_apple_darwin, i686_apple_darwin, i386_apple_ios, x86_64_apple_ios, aarch64_apple_ios, armv7_apple_ios, armv7s_apple_ios, x86_64_pc_windows_gnu, i686_pc_windows_gnu, x86_64_pc_windows_msvc, i686_pc_windows_msvc, le32_unknown_nacl ); let path = Path::new(target); if path.is_file() { return load_file(&path); } let path = { let mut target = target.to_string(); target.push_str(".json"); PathBuf::from(target) }; let target_path = env::var_os("RUST_TARGET_PATH") .unwrap_or(OsString::new()); // FIXME 16351: add a sane default search path? for dir in env::split_paths(&target_path) { let p = dir.join(&path); if p.is_file() { return load_file(&p); } } Err(format!("Could not find specification for target {:?}", target)) } } fn maybe_jemalloc() -> String { if cfg!(disable_jemalloc) { "alloc_system".to_string() } else { "alloc_jemalloc".to_string() } }