| // Copyright 2014 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. |
| |
| use target::TargetOptions; |
| use std::default::Default; |
| |
| pub fn opts() -> TargetOptions { |
| TargetOptions { |
| // FIXME(#13846) this should be enabled for windows |
| function_sections: false, |
| linker: "gcc".to_string(), |
| dynamic_linking: true, |
| executables: true, |
| dll_prefix: "".to_string(), |
| dll_suffix: ".dll".to_string(), |
| exe_suffix: ".exe".to_string(), |
| staticlib_prefix: "".to_string(), |
| staticlib_suffix: ".lib".to_string(), |
| no_default_libraries: true, |
| is_like_windows: true, |
| pre_link_args: vec!( |
| // And here, we see obscure linker flags #45. On windows, it has been |
| // found to be necessary to have this flag to compile liblibc. |
| // |
| // First a bit of background. On Windows, the file format is not ELF, |
| // but COFF (at least according to LLVM). COFF doesn't officially allow |
| // for section names over 8 characters, apparently. Our metadata |
| // section, ".note.rustc", you'll note is over 8 characters. |
| // |
| // On more recent versions of gcc on mingw, apparently the section name |
| // is *not* truncated, but rather stored elsewhere in a separate lookup |
| // table. On older versions of gcc, they apparently always truncated th |
| // section names (at least in some cases). Truncating the section name |
| // actually creates "invalid" objects [1] [2], but only for some |
| // introspection tools, not in terms of whether it can be loaded. |
| // |
| // Long story short, passing this flag forces the linker to *not* |
| // truncate section names (so we can find the metadata section after |
| // it's compiled). The real kicker is that rust compiled just fine on |
| // windows for quite a long time *without* this flag, so I have no idea |
| // why it suddenly started failing for liblibc. Regardless, we |
| // definitely don't want section name truncation, so we're keeping this |
| // flag for windows. |
| // |
| // [1] - https://sourceware.org/bugzilla/show_bug.cgi?id=13130 |
| // [2] - https://code.google.com/p/go/issues/detail?id=2139 |
| "-Wl,--enable-long-section-names".to_string(), |
| |
| // Tell GCC to avoid linker plugins, because we are not bundling |
| // them with Windows installer, and Rust does its own LTO anyways. |
| "-fno-use-linker-plugin".to_string(), |
| |
| // Always enable DEP (NX bit) when it is available |
| "-Wl,--nxcompat".to_string(), |
| |
| // Do not use the standard system startup files or libraries when linking |
| "-nostdlib".to_string(), |
| ), |
| pre_link_objects_exe: vec!( |
| "crt2.o".to_string(), // mingw C runtime initialization for executables |
| "rsbegin.o".to_string(), // Rust compiler runtime initialization, see rsbegin.rs |
| ), |
| pre_link_objects_dll: vec!( |
| "dllcrt2.o".to_string(), // mingw C runtime initialization for dlls |
| "rsbegin.o".to_string(), |
| ), |
| late_link_args: vec!( |
| "-lmingwex".to_string(), |
| "-lmingw32".to_string(), |
| "-lgcc".to_string(), // alas, mingw* libraries above depend on libgcc |
| "-lmsvcrt".to_string(), |
| "-luser32".to_string(), |
| "-lkernel32".to_string(), |
| ), |
| post_link_objects: vec!( |
| "rsend.o".to_string() |
| ), |
| custom_unwind_resume: true, |
| |
| .. Default::default() |
| } |
| } |
