86 lines
4.1 KiB
Rust
86 lines
4.1 KiB
Rust
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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use target::Target;
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pub fn target() -> Target {
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let mut base = super::linux_base::opts();
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base.cpu = "x86-64".to_string();
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base.linker = "musl-gcc".to_string();
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base.pre_link_args.push("-m64".to_string());
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// Make sure that the linker/gcc really don't pull in anything, including
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// default objects, libs, etc.
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base.pre_link_args.push("-nostdlib".to_string());
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base.pre_link_args.push("-static".to_string());
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// At least when this was tested, the linker would not add the
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// `GNU_EH_FRAME` program header to executables generated, which is required
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// when unwinding to locate the unwinding information. I'm not sure why this
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// argument is *not* necessary for normal builds, but it can't hurt!
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base.pre_link_args.push("-Wl,--eh-frame-hdr".to_string());
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// There's a whole bunch of circular dependencies when dealing with MUSL
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// unfortunately. To put this in perspective libc is statically linked to
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// liblibc and libunwind is statically linked to libstd:
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//
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// * libcore depends on `fmod` which is in libc (transitively in liblibc).
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// liblibc, however, depends on libcore.
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// * compiler-rt has personality symbols that depend on libunwind, but
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// libunwind is in libstd which depends on compiler-rt.
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//
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// Recall that linkers discard libraries and object files as much as
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// possible, and with all the static linking and archives flying around with
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// MUSL the linker is super aggressively stripping out objects. For example
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// the first case has fmod stripped from liblibc (it's in its own object
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// file) so it's not there when libcore needs it. In the second example all
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// the unused symbols from libunwind are stripped (each is in its own object
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// file in libstd) before we end up linking compiler-rt which depends on
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// those symbols.
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//
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// To deal with these circular dependencies we just force the compiler to
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// link everything as a group, not stripping anything out until everything
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// is processed. The linker will still perform a pass to strip out object
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// files but it won't do so until all objects/archives have been processed.
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base.pre_link_args.push("-Wl,-(".to_string());
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base.post_link_args.push("-Wl,-)".to_string());
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// When generating a statically linked executable there's generally some
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// small setup needed which is listed in these files. These are provided by
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// a musl toolchain and are linked by default by the `musl-gcc` script. Note
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// that `gcc` also does this by default, it just uses some different files.
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//
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// Each target directory for musl has these object files included in it so
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// they'll be included from there.
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base.pre_link_objects.push("crt1.o".to_string());
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base.pre_link_objects.push("crti.o".to_string());
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base.post_link_objects.push("crtn.o".to_string());
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// MUSL support doesn't currently include dynamic linking, so there's no
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// need for dylibs or rpath business. Additionally `-pie` is incompatible
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// with `-static`, so we can't pass `-pie`.
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base.dynamic_linking = false;
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base.has_rpath = false;
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base.position_independent_executables = false;
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Target {
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data_layout: "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-\
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f32:32:32-f64:64:64-v64:64:64-v128:128:128-a:0:64-\
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s0:64:64-f80:128:128-n8:16:32:64-S128".to_string(),
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llvm_target: "x86_64-unknown-linux-musl".to_string(),
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target_endian: "little".to_string(),
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target_pointer_width: "64".to_string(),
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arch: "x86_64".to_string(),
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target_os: "linux".to_string(),
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target_env: "musl".to_string(),
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options: base,
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}
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}
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