| // Copyright 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 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| //! Shim which is passed to Cargo as "rustc" when running the bootstrap. |
| //! |
| //! This shim will take care of some various tasks that our build process |
| //! requires that Cargo can't quite do through normal configuration: |
| //! |
| //! 1. When compiling build scripts and build dependencies, we need a guaranteed |
| //! full standard library available. The only compiler which actually has |
| //! this is the snapshot, so we detect this situation and always compile with |
| //! the snapshot compiler. |
| //! 2. We pass a bunch of `--cfg` and other flags based on what we're compiling |
| //! (and this slightly differs based on a whether we're using a snapshot or |
| //! not), so we do that all here. |
| //! |
| //! This may one day be replaced by RUSTFLAGS, but the dynamic nature of |
| //! switching compilers for the bootstrap and for build scripts will probably |
| //! never get replaced. |
| |
| extern crate bootstrap; |
| |
| use std::env; |
| use std::ffi::OsString; |
| use std::path::PathBuf; |
| use std::process::Command; |
| |
| fn main() { |
| let args = env::args_os().skip(1).collect::<Vec<_>>(); |
| // Detect whether or not we're a build script depending on whether --target |
| // is passed (a bit janky...) |
| let target = args.windows(2).find(|w| &*w[0] == "--target") |
| .and_then(|w| w[1].to_str()); |
| |
| // Build scripts always use the snapshot compiler which is guaranteed to be |
| // able to produce an executable, whereas intermediate compilers may not |
| // have the standard library built yet and may not be able to produce an |
| // executable. Otherwise we just use the standard compiler we're |
| // bootstrapping with. |
| let (rustc, libdir) = if target.is_none() { |
| ("RUSTC_SNAPSHOT", "RUSTC_SNAPSHOT_LIBDIR") |
| } else { |
| ("RUSTC_REAL", "RUSTC_LIBDIR") |
| }; |
| let stage = env::var("RUSTC_STAGE").unwrap(); |
| |
| let rustc = env::var_os(rustc).unwrap(); |
| let libdir = env::var_os(libdir).unwrap(); |
| let mut dylib_path = bootstrap::util::dylib_path(); |
| dylib_path.insert(0, PathBuf::from(libdir)); |
| |
| let mut cmd = Command::new(rustc); |
| cmd.args(&args) |
| .arg("--cfg").arg(format!("stage{}", stage)) |
| .env(bootstrap::util::dylib_path_var(), |
| env::join_paths(&dylib_path).unwrap()); |
| |
| if let Some(target) = target { |
| // The stage0 compiler has a special sysroot distinct from what we |
| // actually downloaded, so we just always pass the `--sysroot` option. |
| cmd.arg("--sysroot").arg(env::var_os("RUSTC_SYSROOT").unwrap()); |
| |
| // When we build Rust dylibs they're all intended for intermediate |
| // usage, so make sure we pass the -Cprefer-dynamic flag instead of |
| // linking all deps statically into the dylib. |
| cmd.arg("-Cprefer-dynamic"); |
| |
| // Help the libc crate compile by assisting it in finding the MUSL |
| // native libraries. |
| if let Some(s) = env::var_os("MUSL_ROOT") { |
| let mut root = OsString::from("native="); |
| root.push(&s); |
| root.push("/lib"); |
| cmd.arg("-L").arg(&root); |
| } |
| |
| // Pass down extra flags, commonly used to configure `-Clinker` when |
| // cross compiling. |
| if let Ok(s) = env::var("RUSTC_FLAGS") { |
| cmd.args(&s.split(" ").filter(|s| !s.is_empty()).collect::<Vec<_>>()); |
| } |
| |
| // If we're compiling specifically the `panic_abort` crate then we pass |
| // the `-C panic=abort` option. Note that we do not do this for any |
| // other crate intentionally as this is the only crate for now that we |
| // ship with panic=abort. |
| // |
| // This... is a bit of a hack how we detect this. Ideally this |
| // information should be encoded in the crate I guess? Would likely |
| // require an RFC amendment to RFC 1513, however. |
| let is_panic_abort = args.windows(2).any(|a| { |
| &*a[0] == "--crate-name" && &*a[1] == "panic_abort" |
| }); |
| // FIXME(stage0): remove this `stage != "0"` condition |
| if is_panic_abort && stage != "0" { |
| cmd.arg("-C").arg("panic=abort"); |
| } |
| |
| // Set various options from config.toml to configure how we're building |
| // code. |
| if env::var("RUSTC_DEBUGINFO") == Ok("true".to_string()) { |
| cmd.arg("-g"); |
| } |
| let debug_assertions = match env::var("RUSTC_DEBUG_ASSERTIONS") { |
| Ok(s) => if s == "true" {"y"} else {"n"}, |
| Err(..) => "n", |
| }; |
| cmd.arg("-C").arg(format!("debug-assertions={}", debug_assertions)); |
| if let Ok(s) = env::var("RUSTC_CODEGEN_UNITS") { |
| cmd.arg("-C").arg(format!("codegen-units={}", s)); |
| } |
| |
| // Dealing with rpath here is a little special, so let's go into some |
| // detail. First off, `-rpath` is a linker option on Unix platforms |
| // which adds to the runtime dynamic loader path when looking for |
| // dynamic libraries. We use this by default on Unix platforms to ensure |
| // that our nightlies behave the same on Windows, that is they work out |
| // of the box. This can be disabled, of course, but basically that's why |
| // we're gated on RUSTC_RPATH here. |
| // |
| // Ok, so the astute might be wondering "why isn't `-C rpath` used |
| // here?" and that is indeed a good question to task. This codegen |
| // option is the compiler's current interface to generating an rpath. |
| // Unfortunately it doesn't quite suffice for us. The flag currently |
| // takes no value as an argument, so the compiler calculates what it |
| // should pass to the linker as `-rpath`. This unfortunately is based on |
| // the **compile time** directory structure which when building with |
| // Cargo will be very different than the runtime directory structure. |
| // |
| // All that's a really long winded way of saying that if we use |
| // `-Crpath` then the executables generated have the wrong rpath of |
| // something like `$ORIGIN/deps` when in fact the way we distribute |
| // rustc requires the rpath to be `$ORIGIN/../lib`. |
| // |
| // So, all in all, to set up the correct rpath we pass the linker |
| // argument manually via `-C link-args=-Wl,-rpath,...`. Plus isn't it |
| // fun to pass a flag to a tool to pass a flag to pass a flag to a tool |
| // to change a flag in a binary? |
| if env::var("RUSTC_RPATH") == Ok("true".to_string()) { |
| let rpath = if target.contains("apple") { |
| Some("-Wl,-rpath,@loader_path/../lib") |
| } else if !target.contains("windows") { |
| Some("-Wl,-rpath,$ORIGIN/../lib") |
| } else { |
| None |
| }; |
| if let Some(rpath) = rpath { |
| cmd.arg("-C").arg(format!("link-args={}", rpath)); |
| } |
| } |
| } |
| |
| // Actually run the compiler! |
| std::process::exit(match cmd.status() { |
| Ok(s) => s.code().unwrap_or(1), |
| Err(e) => panic!("\n\nfailed to run {:?}: {}\n\n", cmd, e), |
| }) |
| } |
