Auto merge of rust-lang#33359 - tamird:consolidate-musl, r=alexcrichton

rustc_back: use a common musl base

extracted from rust-lang#33327.

cc rust-lang#33189.

r? @alexcrichton

Author: bors

src/librustc_back/target/i686_unknown_linux_musl.rs

@@ -8,31 +8,14 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// See x86_64_unknown_linux_musl for explanation of arguments
-
 use target::Target;
 
 pub fn target() -> Target {
-    let mut base = super::linux_base::opts();
+    let mut base = super::linux_musl_base::opts();
     base.cpu = "pentium4".to_string();
     base.pre_link_args.push("-m32".to_string());
     base.pre_link_args.push("-Wl,-melf_i386".to_string());
 
-    base.pre_link_args.push("-nostdlib".to_string());
-    base.pre_link_args.push("-static".to_string());
-    base.pre_link_args.push("-Wl,--eh-frame-hdr".to_string());
-
-    base.pre_link_args.push("-Wl,-(".to_string());
-    base.post_link_args.push("-Wl,-)".to_string());
-
-    base.pre_link_objects_exe.push("crt1.o".to_string());
-    base.pre_link_objects_exe.push("crti.o".to_string());
-    base.post_link_objects.push("crtn.o".to_string());
-
-    base.dynamic_linking = false;
-    base.has_rpath = false;
-    base.position_independent_executables = false;
-
     Target {
         llvm_target: "i686-unknown-linux-musl".to_string(),
         target_endian: "little".to_string(),

src/librustc_back/target/linux_musl_base.rs

@@ -0,0 +1,71 @@
+// Copyright 2016 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;
+
+pub fn opts() -> TargetOptions {
+    let mut base = super::linux_base::opts();
+
+    // 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_exe.push("crt1.o".to_string());
+    base.pre_link_objects_exe.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;
+
+    base
+}

src/librustc_back/target/mod.rs

@@ -56,6 +56,7 @@ mod bitrig_base;
 mod dragonfly_base;
 mod freebsd_base;
 mod linux_base;
+mod linux_musl_base;
 mod openbsd_base;
 mod netbsd_base;
 mod solaris_base;

src/librustc_back/target/x86_64_unknown_linux_musl.rs

@@ -11,64 +11,10 @@
 use target::Target;
 
 pub fn target() -> Target {
-    let mut base = super::linux_base::opts();
+    let mut base = super::linux_musl_base::opts();
     base.cpu = "x86-64".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_exe.push("crt1.o".to_string());
-    base.pre_link_objects_exe.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 {
         llvm_target: "x86_64-unknown-linux-musl".to_string(),
         target_endian: "little".to_string(),