src/toolchain.rs

   1 //! Locating various executables part of a C toolchain.
   2
   3 use std::path::PathBuf;
   4
   5 use rustc_middle::bug;
   6 use rustc_session::Session;
   7 use rustc_target::spec::LinkerFlavor;
   8
   9 /// Tries to infer the path of a binary for the target toolchain from the linker name.
  10 pub(crate) fn get_toolchain_binary(sess: &Session, tool: &str) -> PathBuf {
  11     let (mut linker, _linker_flavor) = linker_and_flavor(sess);
  12     let linker_file_name = linker
  13         .file_name()
  14         .and_then(|name| name.to_str())
  15         .unwrap_or_else(|| sess.fatal("couldn't extract file name from specified linker"));
  16
  17     if linker_file_name == "ld.lld" {
  18         if tool != "ld" {
  19             linker.set_file_name(tool)
  20         }
  21     } else {
  22         let tool_file_name = linker_file_name
  23             .replace("ld", tool)
  24             .replace("gcc", tool)
  25             .replace("clang", tool)
  26             .replace("cc", tool);
  27
  28         linker.set_file_name(tool_file_name)
  29     }
  30
  31     linker
  32 }
  33
  34 // Adapted from https://github.com/rust-lang/rust/blob/5db778affee7c6600c8e7a177c48282dab3f6292/src/librustc_codegen_ssa/back/link.rs#L848-L931
  35 fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) {
  36     fn infer_from(
  37         sess: &Session,
  38         linker: Option<PathBuf>,
  39         flavor: Option<LinkerFlavor>,
  40     ) -> Option<(PathBuf, LinkerFlavor)> {
  41         match (linker, flavor) {
  42             (Some(linker), Some(flavor)) => Some((linker, flavor)),
  43             // only the linker flavor is known; use the default linker for the selected flavor
  44             (None, Some(flavor)) => Some((
  45                 PathBuf::from(match flavor {
  46                     LinkerFlavor::Em => {
  47                         if cfg!(windows) {
  48                             "emcc.bat"
  49                         } else {
  50                             "emcc"
  51                         }
  52                     }
  53                     LinkerFlavor::Gcc => {
  54                         if cfg!(any(target_os = "solaris", target_os = "illumos")) {
  55                             // On historical Solaris systems, "cc" may have
  56                             // been Sun Studio, which is not flag-compatible
  57                             // with "gcc".  This history casts a long shadow,
  58                             // and many modern illumos distributions today
  59                             // ship GCC as "gcc" without also making it
  60                             // available as "cc".
  61                             "gcc"
  62                         } else {
  63                             "cc"
  64                         }
  65                     }
  66                     LinkerFlavor::Ld => "ld",
  67                     LinkerFlavor::Msvc => "link.exe",
  68                     LinkerFlavor::Lld(_) => "lld",
  69                     LinkerFlavor::PtxLinker => "rust-ptx-linker",
  70                 }),
  71                 flavor,
  72             )),
  73             (Some(linker), None) => {
  74                 let stem = linker.file_stem().and_then(|stem| stem.to_str()).unwrap_or_else(|| {
  75                     sess.fatal("couldn't extract file stem from specified linker")
  76                 });
  77
  78                 let flavor = if stem == "emcc" {
  79                     LinkerFlavor::Em
  80                 } else if stem == "gcc"
  81                     || stem.ends_with("-gcc")
  82                     || stem == "clang"
  83                     || stem.ends_with("-clang")
  84                 {
  85                     LinkerFlavor::Gcc
  86                 } else if stem == "ld" || stem == "ld.lld" || stem.ends_with("-ld") {
  87                     LinkerFlavor::Ld
  88                 } else if stem == "link" || stem == "lld-link" {
  89                     LinkerFlavor::Msvc
  90                 } else if stem == "lld" || stem == "rust-lld" {
  91                     LinkerFlavor::Lld(sess.target.lld_flavor)
  92                 } else {
  93                     // fall back to the value in the target spec
  94                     sess.target.linker_flavor
  95                 };
  96
  97                 Some((linker, flavor))
  98             }
  99             (None, None) => None,
 100         }
 101     }
 102
 103     // linker and linker flavor specified via command line have precedence over what the target
 104     // specification specifies
 105     if let Some(ret) = infer_from(sess, sess.opts.cg.linker.clone(), sess.opts.cg.linker_flavor) {
 106         return ret;
 107     }
 108
 109     if let Some(ret) = infer_from(
 110         sess,
 111         sess.target.linker.clone().map(PathBuf::from),
 112         Some(sess.target.linker_flavor),
 113     ) {
 114         return ret;
 115     }
 116
 117     bug!("Not enough information provided to determine how to invoke the linker");
 118 }