1 // Copyright 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 //! Shim which is passed to Cargo as "rustc" when running the bootstrap.
13 //! This shim will take care of some various tasks that our build process
14 //! requires that Cargo can't quite do through normal configuration:
16 //! 1. When compiling build scripts and build dependencies, we need a guaranteed
17 //! full standard library available. The only compiler which actually has
18 //! this is the snapshot, so we detect this situation and always compile with
19 //! the snapshot compiler.
20 //! 2. We pass a bunch of `--cfg` and other flags based on what we're compiling
21 //! (and this slightly differs based on a whether we're using a snapshot or
22 //! not), so we do that all here.
24 //! This may one day be replaced by RUSTFLAGS, but the dynamic nature of
25 //! switching compilers for the bootstrap and for build scripts will probably
26 //! never get replaced.
30 extern crate bootstrap;
33 use std::ffi::OsString;
35 use std::io::prelude::*;
36 use std::str::FromStr;
37 use std::path::PathBuf;
38 use std::process::{Command, ExitStatus};
41 let args = env::args_os().skip(1).collect::<Vec<_>>();
42 // Detect whether or not we're a build script depending on whether --target
43 // is passed (a bit janky...)
44 let target = args.windows(2)
45 .find(|w| &*w[0] == "--target")
46 .and_then(|w| w[1].to_str());
47 let version = args.iter().find(|w| &**w == "-vV");
49 let verbose = match env::var("RUSTC_VERBOSE") {
50 Ok(s) => usize::from_str(&s).expect("RUSTC_VERBOSE should be an integer"),
54 // Build scripts always use the snapshot compiler which is guaranteed to be
55 // able to produce an executable, whereas intermediate compilers may not
56 // have the standard library built yet and may not be able to produce an
57 // executable. Otherwise we just use the standard compiler we're
58 // bootstrapping with.
60 // Also note that cargo will detect the version of the compiler to trigger
61 // a rebuild when the compiler changes. If this happens, we want to make
62 // sure to use the actual compiler instead of the snapshot compiler becase
63 // that's the one that's actually changing.
64 let (rustc, libdir) = if target.is_none() && version.is_none() {
65 ("RUSTC_SNAPSHOT", "RUSTC_SNAPSHOT_LIBDIR")
67 ("RUSTC_REAL", "RUSTC_LIBDIR")
69 let stage = env::var("RUSTC_STAGE").expect("RUSTC_STAGE was not set");
70 let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
71 let mut on_fail = env::var_os("RUSTC_ON_FAIL").map(|of| Command::new(of));
73 let rustc = env::var_os(rustc).unwrap_or_else(|| panic!("{:?} was not set", rustc));
74 let libdir = env::var_os(libdir).unwrap_or_else(|| panic!("{:?} was not set", libdir));
75 let mut dylib_path = bootstrap::util::dylib_path();
76 dylib_path.insert(0, PathBuf::from(libdir));
78 let mut cmd = Command::new(rustc);
81 .arg(format!("stage{}", stage))
82 .env(bootstrap::util::dylib_path_var(),
83 env::join_paths(&dylib_path).unwrap());
85 if let Some(target) = target {
86 // The stage0 compiler has a special sysroot distinct from what we
87 // actually downloaded, so we just always pass the `--sysroot` option.
88 cmd.arg("--sysroot").arg(sysroot);
90 // When we build Rust dylibs they're all intended for intermediate
91 // usage, so make sure we pass the -Cprefer-dynamic flag instead of
92 // linking all deps statically into the dylib.
93 if env::var_os("RUSTC_NO_PREFER_DYNAMIC").is_none() {
94 cmd.arg("-Cprefer-dynamic");
97 // Help the libc crate compile by assisting it in finding the MUSL
99 if let Some(s) = env::var_os("MUSL_ROOT") {
100 let mut root = OsString::from("native=");
103 cmd.arg("-L").arg(&root);
106 // Pass down extra flags, commonly used to configure `-Clinker` when
108 if let Ok(s) = env::var("RUSTC_FLAGS") {
109 cmd.args(&s.split(" ").filter(|s| !s.is_empty()).collect::<Vec<_>>());
112 // Pass down incremental directory, if any.
113 if let Ok(dir) = env::var("RUSTC_INCREMENTAL") {
114 cmd.arg(format!("-Zincremental={}", dir));
117 cmd.arg("-Zincremental-info");
121 // If we're compiling specifically the `panic_abort` crate then we pass
122 // the `-C panic=abort` option. Note that we do not do this for any
123 // other crate intentionally as this is the only crate for now that we
124 // ship with panic=abort.
126 // This... is a bit of a hack how we detect this. Ideally this
127 // information should be encoded in the crate I guess? Would likely
128 // require an RFC amendment to RFC 1513, however.
129 let is_panic_abort = args.windows(2)
130 .any(|a| &*a[0] == "--crate-name" && &*a[1] == "panic_abort");
132 cmd.arg("-C").arg("panic=abort");
135 // Set various options from config.toml to configure how we're building
137 if env::var("RUSTC_DEBUGINFO") == Ok("true".to_string()) {
139 } else if env::var("RUSTC_DEBUGINFO_LINES") == Ok("true".to_string()) {
140 cmd.arg("-Cdebuginfo=1");
142 let debug_assertions = match env::var("RUSTC_DEBUG_ASSERTIONS") {
143 Ok(s) => if s == "true" { "y" } else { "n" },
146 cmd.arg("-C").arg(format!("debug-assertions={}", debug_assertions));
147 if let Ok(s) = env::var("RUSTC_CODEGEN_UNITS") {
148 cmd.arg("-C").arg(format!("codegen-units={}", s));
151 // Emit save-analysis info.
152 if env::var("RUSTC_SAVE_ANALYSIS") == Ok("api".to_string()) {
153 cmd.arg("-Zsave-analysis-api");
156 // Dealing with rpath here is a little special, so let's go into some
157 // detail. First off, `-rpath` is a linker option on Unix platforms
158 // which adds to the runtime dynamic loader path when looking for
159 // dynamic libraries. We use this by default on Unix platforms to ensure
160 // that our nightlies behave the same on Windows, that is they work out
161 // of the box. This can be disabled, of course, but basically that's why
162 // we're gated on RUSTC_RPATH here.
164 // Ok, so the astute might be wondering "why isn't `-C rpath` used
165 // here?" and that is indeed a good question to task. This codegen
166 // option is the compiler's current interface to generating an rpath.
167 // Unfortunately it doesn't quite suffice for us. The flag currently
168 // takes no value as an argument, so the compiler calculates what it
169 // should pass to the linker as `-rpath`. This unfortunately is based on
170 // the **compile time** directory structure which when building with
171 // Cargo will be very different than the runtime directory structure.
173 // All that's a really long winded way of saying that if we use
174 // `-Crpath` then the executables generated have the wrong rpath of
175 // something like `$ORIGIN/deps` when in fact the way we distribute
176 // rustc requires the rpath to be `$ORIGIN/../lib`.
178 // So, all in all, to set up the correct rpath we pass the linker
179 // argument manually via `-C link-args=-Wl,-rpath,...`. Plus isn't it
180 // fun to pass a flag to a tool to pass a flag to pass a flag to a tool
181 // to change a flag in a binary?
182 if env::var("RUSTC_RPATH") == Ok("true".to_string()) {
183 let rpath = if target.contains("apple") {
185 // Note that we need to take one extra step on OSX to also pass
186 // `-Wl,-instal_name,@rpath/...` to get things to work right. To
187 // do that we pass a weird flag to the compiler to get it to do
188 // so. Note that this is definitely a hack, and we should likely
189 // flesh out rpath support more fully in the future.
191 cmd.arg("-Z").arg("osx-rpath-install-name");
193 Some("-Wl,-rpath,@loader_path/../lib")
194 } else if !target.contains("windows") {
195 Some("-Wl,-rpath,$ORIGIN/../lib")
199 if let Some(rpath) = rpath {
200 cmd.arg("-C").arg(format!("link-args={}", rpath));
203 if let Ok(s) = env::var("RUSTFLAGS") {
204 for flag in s.split_whitespace() {
210 if target.contains("pc-windows-msvc") {
211 cmd.arg("-Z").arg("unstable-options");
212 cmd.arg("-C").arg("target-feature=+crt-static");
217 writeln!(&mut io::stderr(), "rustc command: {:?}", cmd).unwrap();
220 // Actually run the compiler!
221 std::process::exit(if let Some(ref mut on_fail) = on_fail {
223 Ok(s) if s.success() => 0,
225 println!("\nDid not run successfully:\n{:?}\n-------------", cmd);
226 exec_cmd(on_fail).expect("could not run the backup command");
231 std::process::exit(match exec_cmd(&mut cmd) {
232 Ok(s) => s.code().unwrap_or(0xfe),
233 Err(e) => panic!("\n\nfailed to run {:?}: {}\n\n", cmd, e),
239 fn exec_cmd(cmd: &mut Command) -> ::std::io::Result<ExitStatus> {
240 use std::os::unix::process::CommandExt;
245 fn exec_cmd(cmd: &mut Command) -> ::std::io::Result<ExitStatus> {