diff options
| -rw-r--r-- | src/librustc_back/target/linux_base.rs | 14 | ||||
| -rw-r--r-- | src/librustc_back/target/mod.rs | 28 | ||||
| -rw-r--r-- | src/librustc_back/target/x86_64_unknown_linux_musl.rs | 85 |
3 files changed, 96 insertions, 31 deletions
diff --git a/src/librustc_back/target/linux_base.rs b/src/librustc_back/target/linux_base.rs index d267bc77e49..823a4a81fa4 100644 --- a/src/librustc_back/target/linux_base.rs +++ b/src/librustc_back/target/linux_base.rs @@ -19,12 +19,16 @@ pub fn opts() -> TargetOptions { morestack: true, linker_is_gnu: true, has_rpath: true, - pre_link_args: vec!( - // GNU-style linkers will use this to omit linking to libraries which - // don't actually fulfill any relocations, but only for libraries which - // follow this flag. Thus, use it before specifying libraries to link to. + pre_link_args: vec![ + // We want to be able to strip as much executable code as possible + // from the linker command line, and this flag indicates to the + // linker that it can avoid linking in dynamic libraries that don't + // actually satisfy any symbols up to that point (as with many other + // resolutions the linker does). This option only applies to all + // following libraries so we're sure to pass it as one of the first + // arguments. "-Wl,--as-needed".to_string(), - ), + ], position_independent_executables: true, .. Default::default() } diff --git a/src/librustc_back/target/mod.rs b/src/librustc_back/target/mod.rs index cf7499a337d..c32eacda2a2 100644 --- a/src/librustc_back/target/mod.rs +++ b/src/librustc_back/target/mod.rs @@ -59,32 +59,6 @@ mod dragonfly_base; mod bitrig_base; mod openbsd_base; -mod armv7_apple_ios; -mod armv7s_apple_ios; -mod i386_apple_ios; - -mod arm_linux_androideabi; -mod arm_unknown_linux_gnueabi; -mod arm_unknown_linux_gnueabihf; -mod aarch64_apple_ios; -mod aarch64_linux_android; -mod aarch64_unknown_linux_gnu; -mod i686_apple_darwin; -mod i686_pc_windows_gnu; -mod i686_unknown_dragonfly; -mod i686_unknown_linux_gnu; -mod mips_unknown_linux_gnu; -mod mipsel_unknown_linux_gnu; -mod powerpc_unknown_linux_gnu; -mod x86_64_apple_darwin; -mod x86_64_apple_ios; -mod x86_64_pc_windows_gnu; -mod x86_64_unknown_freebsd; -mod x86_64_unknown_dragonfly; -mod x86_64_unknown_bitrig; -mod x86_64_unknown_linux_gnu; -mod x86_64_unknown_openbsd; - /// Everything `rustc` knows about how to compile for a specific target. /// /// Every field here must be specified, and has no default value. @@ -333,6 +307,7 @@ impl Target { macro_rules! load_specific { ( $($name:ident),+ ) => ( { + $(mod $name;)* let target = target.replace("-", "_"); if false { } $( @@ -362,6 +337,7 @@ impl Target { arm_unknown_linux_gnueabi, arm_unknown_linux_gnueabihf, aarch64_unknown_linux_gnu, + x86_64_unknown_linux_musl, arm_linux_androideabi, aarch64_linux_android, diff --git a/src/librustc_back/target/x86_64_unknown_linux_musl.rs b/src/librustc_back/target/x86_64_unknown_linux_musl.rs new file mode 100644 index 00000000000..74d61e90f67 --- /dev/null +++ b/src/librustc_back/target/x86_64_unknown_linux_musl.rs @@ -0,0 +1,85 @@ +// 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::Target; + +pub fn target() -> Target { + let mut base = super::linux_base::opts(); + base.cpu = "x86-64".to_string(); + base.linker = "musl-gcc".to_string(); + base.pre_link_args.push("-m64".to_string()); + + // Make sure that the linker/gcc really don't pull in anything, including + // default objects, libs, etc. + base.pre_link_args.push("-nostdlib".to_string()); + base.pre_link_args.push("-static".to_string()); + + // At least when this was tested, the linker would not add the + // `GNU_EH_FRAME` program header to executables generated, which is required + // when unwinding to locate the unwinding information. I'm not sure why this + // argument is *not* necessary for normal builds, but it can't hurt! + base.pre_link_args.push("-Wl,--eh-frame-hdr".to_string()); + + // There's a whole bunch of circular dependencies when dealing with MUSL + // unfortunately. To put this in perspective libc is statically linked to + // liblibc and libunwind is statically linked to libstd: + // + // * libcore depends on `fmod` which is in libc (transitively in liblibc). + // liblibc, however, depends on libcore. + // * compiler-rt has personality symbols that depend on libunwind, but + // libunwind is in libstd which depends on compiler-rt. + // + // Recall that linkers discard libraries and object files as much as + // possible, and with all the static linking and archives flying around with + // MUSL the linker is super aggressively stripping out objects. For example + // the first case has fmod stripped from liblibc (it's in its own object + // file) so it's not there when libcore needs it. In the second example all + // the unused symbols from libunwind are stripped (each is in its own object + // file in libstd) before we end up linking compiler-rt which depends on + // those symbols. + // + // To deal with these circular dependencies we just force the compiler to + // link everything as a group, not stripping anything out until everything + // is processed. The linker will still perform a pass to strip out object + // files but it won't do so until all objects/archives have been processed. + base.pre_link_args.push("-Wl,-(".to_string()); + base.post_link_args.push("-Wl,-)".to_string()); + + // When generating a statically linked executable there's generally some + // small setup needed which is listed in these files. These are provided by + // a musl toolchain and are linked by default by the `musl-gcc` script. Note + // that `gcc` also does this by default, it just uses some different files. + // + // Each target directory for musl has these object files included in it so + // they'll be included from there. + base.pre_link_objects.push("crt1.o".to_string()); + base.pre_link_objects.push("crti.o".to_string()); + base.post_link_objects.push("crtn.o".to_string()); + + // MUSL support doesn't currently include dynamic linking, so there's no + // need for dylibs or rpath business. Additionally `-pie` is incompatible + // with `-static`, so we can't pass `-pie`. + base.dynamic_linking = false; + base.has_rpath = false; + base.position_independent_executables = false; + + Target { + data_layout: "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-\ + f32:32:32-f64:64:64-v64:64:64-v128:128:128-a:0:64-\ + s0:64:64-f80:128:128-n8:16:32:64-S128".to_string(), + llvm_target: "x86_64-unknown-linux-musl".to_string(), + target_endian: "little".to_string(), + target_pointer_width: "64".to_string(), + arch: "x86_64".to_string(), + target_os: "linux".to_string(), + target_env: "musl".to_string(), + options: base, + } +} |