src/toolchain.rs

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