compiler/rustc_target/src/lib.rs

   1 //! Some stuff used by rustc that doesn't have many dependencies
   2 //!
   3 //! Originally extracted from rustc::back, which was nominally the
   4 //! compiler 'backend', though LLVM is rustc's backend, so rustc_target
   5 //! is really just odds-and-ends relating to code gen and linking.
   6 //! This crate mostly exists to make rustc smaller, so we might put
   7 //! more 'stuff' here in the future. It does not have a dependency on
   8 //! LLVM.
   9
  10 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
  11 #![feature(bool_to_option)]
  12 #![feature(nll)]
  13 #![feature(never_type)]
  14 #![feature(associated_type_bounds)]
  15 #![feature(exhaustive_patterns)]
  16 #![feature(min_specialization)]
  17
  18 use std::path::{Path, PathBuf};
  19
  20 #[macro_use]
  21 extern crate rustc_macros;
  22
  23 #[macro_use]
  24 extern crate tracing;
  25
  26 pub mod abi;
  27 pub mod asm;
  28 pub mod spec;
  29
  30 /// Requirements for a `StableHashingContext` to be used in this crate.
  31 /// This is a hack to allow using the `HashStable_Generic` derive macro
  32 /// instead of implementing everything in `rustc_middle`.
  33 pub trait HashStableContext {}
  34
  35 /// The name of rustc's own place to organize libraries.
  36 ///
  37 /// Used to be `rustc`, now the default is `rustlib`.
  38 const RUST_LIB_DIR: &str = "rustlib";
  39
  40 /// Returns a `rustlib` path for this particular target, relative to the provided sysroot.
  41 ///
  42 /// For example: `target_sysroot_path("/usr", "x86_64-unknown-linux-gnu")` =>
  43 /// `"lib*/rustlib/x86_64-unknown-linux-gnu"`.
  44 pub fn target_rustlib_path(sysroot: &Path, target_triple: &str) -> PathBuf {
  45     let libdir = find_libdir(sysroot);
  46     std::array::IntoIter::new([
  47         Path::new(libdir.as_ref()),
  48         Path::new(RUST_LIB_DIR),
  49         Path::new(target_triple),
  50     ])
  51     .collect::<PathBuf>()
  52 }
  53
  54 /// The name of the directory rustc expects libraries to be located.
  55 fn find_libdir(sysroot: &Path) -> std::borrow::Cow<'static, str> {
  56     // FIXME: This is a quick hack to make the rustc binary able to locate
  57     // Rust libraries in Linux environments where libraries might be installed
  58     // to lib64/lib32. This would be more foolproof by basing the sysroot off
  59     // of the directory where `librustc_driver` is located, rather than
  60     // where the rustc binary is.
  61     // If --libdir is set during configuration to the value other than
  62     // "lib" (i.e., non-default), this value is used (see issue #16552).
  63
  64     #[cfg(target_pointer_width = "64")]
  65     const PRIMARY_LIB_DIR: &str = "lib64";
  66
  67     #[cfg(target_pointer_width = "32")]
  68     const PRIMARY_LIB_DIR: &str = "lib32";
  69
  70     const SECONDARY_LIB_DIR: &str = "lib";
  71
  72     match option_env!("CFG_LIBDIR_RELATIVE") {
  73         None | Some("lib") => {
  74             if sysroot.join(PRIMARY_LIB_DIR).join(RUST_LIB_DIR).exists() {
  75                 PRIMARY_LIB_DIR.into()
  76             } else {
  77                 SECONDARY_LIB_DIR.into()
  78             }
  79         }
  80         Some(libdir) => libdir.into(),
  81     }
  82 }