src/librustc_back/target/windows_msvc_base.rs

   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.
   4 //
   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.
  10
  11 use target::TargetOptions;
  12 use std::default::Default;
  13
  14 pub fn opts() -> TargetOptions {
  15     TargetOptions {
  16         function_sections: true,
  17         linker: "link.exe".to_string(),
  18         // When taking a look at the value of this `ar` field, one might expect
  19         // `lib.exe` to be the value here! The `lib.exe` program is the default
  20         // tool for managing `.lib` archives on Windows, but unfortunately the
  21         // compiler cannot use it.
  22         //
  23         // To recap, we use `ar` here to manage rlibs (which are just archives).
  24         // LLVM does not expose bindings for modifying archives so we have to
  25         // invoke this utility for write operations (e.g. deleting files, adding
  26         // files, etc). Normally archives only have object files within them,
  27         // but the compiler also uses archives for storing metadata and
  28         // compressed bytecode, so we don't exactly fall within "normal use
  29         // cases".
  30         //
  31         // MSVC's `lib.exe` tool by default will choke when adding a non-object
  32         // file to an archive, which we do on a regular basis, making it
  33         // inoperable for us. Luckily, however, LLVM has already rewritten `ar`
  34         // in the form of `llvm-ar` which is built by default when we build
  35         // LLVM. This tool, unlike `lib.exe`, works just fine with non-object
  36         // files, so we use it instead.
  37         //
  38         // Note that there's a few caveats associated with this:
  39         //
  40         // * This still requires that the *linker* (the consumer of rlibs) will
  41         //   ignore non-object files. Thankfully `link.exe` on Windows does
  42         //   indeed ignore non-object files in archives.
  43         // * This requires `llvm-ar.exe` to be distributed with the compiler
  44         //   itself, but we already make sure of this elsewhere.
  45         //
  46         // Perhaps one day we won't even need this tool at all and we'll just be
  47         // able to make library calls into LLVM!
  48         ar: "llvm-ar.exe".to_string(),
  49         dynamic_linking: true,
  50         executables: true,
  51         dll_prefix: "".to_string(),
  52         dll_suffix: ".dll".to_string(),
  53         exe_suffix: ".exe".to_string(),
  54         staticlib_prefix: "".to_string(),
  55         staticlib_suffix: ".lib".to_string(),
  56         morestack: false,
  57         is_like_windows: true,
  58         is_like_msvc: true,
  59         pre_link_args: vec![
  60             "/NOLOGO".to_string(),
  61             "/NXCOMPAT".to_string(),
  62         ],
  63
  64         .. Default::default()
  65     }
  66 }