Rust can be compiled against musl libc without cross-compilation from glibc

[frol]

According to this resolved issue: rust-lang/rust#28667, Rust should be able to be compiled against musl libc on a musl libc-based OS. It seems it is time to build an Alpine package: https://bugs.alpinelinux.org/issues/3949

[antoineco]

Did you find a way to do so? My compilation always fails with

make: compiler-rt
make[1]: Entering directory '/rust-master/src/compiler-rt'
make[1]: *** No rule to make target 'triple-builtins'.  Stop.
make[1]: Leaving directory '/rust-master/src/compiler-rt'
/rust-master/mk/rt.mk:404: recipe for target 'x86_64-unknown-linux-gnu/rt/libcompiler-rt.a' failed
make: *** [x86_64-unknown-linux-gnu/rt/libcompiler-rt.a] Error 2

I used the following Dockerfile for reference:

FROM alpine:3.3

RUN apk add --no-cache curl

# build Rust
RUN curl -LO https://github.com/rust-lang/rust/archive/master.zip \
  && unzip master.zip \
  && rm master.zip \
  && cd rust-master \
  && apk add --no-cache --virtual .build-deps \
      python \
      file \
      make \
      g++ \
      llvm-dev \
      musl-dev \
  && apk add libunwind-dev --no-cache --repository http://dl-3.alpinelinux.org/alpine/edge/testing/ \
  && ./configure \
       --target=x86_64-unknown-linux-musl \
       --musl-root=/usr \
       --llvm-root=/usr \
       --disable-codegen-tests \
       --disable-docs \
  && make

[frol]

Nope, I haven't had time yet to try. May be you ask this question in that issue discussion?

[antoineco]

Sure, I was just curious. It seems like it's still necessary to cross compile using a glibc.

[sanmai-NL]

With some hacks to the Dockerfile, I got a tiny bit further: in the end I ran into rust-lang/rust#28667.

The configure parameters --enable-dist-host-only, --enable-llvm-static-stdcpp that I thought could be relevant seem not to be, the build failure is the same with or without. Using --llvm-root I bumped into rust-lang/rust#27254, so I dropped that.

FROM alpine:3.3

RUN apk add --no-cache 'curl'
# TODO: Verify download.
RUN curl -LOsS 'https://static.rust-lang.org/dist/rustc-1.8.0-src.tar.gz' \
  && tar -xzvf 'rustc-1.8.0-src.tar.gz' \
  && cd 'rustc-1.8.0/' \
  && apk add --no-cache --virtual '.build-deps' \
      'tree' \
      'python' \
      'file' \
      'make' \
      'g++' \
      'llvm-dev' \
      'musl-dev' \
  && apk add 'libunwind-dev' --no-cache --repository 'http://nl.alpinelinux.org/alpine/edge/testing/'
RUN ln -vsf '/bin/true' '/usr/bin/FileCheck' \
  && chmod a+x '/usr/bin/FileCheck'
RUN cd 'rustc-1.8.0/' \
  && ./configure \
       --enable-dist-host-only \
       --enable-llvm-static-stdcpp \
       --target='x86_64-unknown-linux-musl' \
       --musl-root='/usr' \
       --prefix='/usr'
  && make install

make[3]: Entering directory '/rustc-1.8.0/x86_64-unknown-linux-gnu/llvm/lib/Support'
llvm[3]: Compiling APFloat.cpp for Release build
llvm[3]: Compiling APInt.cpp for Release build
llvm[3]: Compiling APSInt.cpp for Release build
llvm[3]: Compiling ARMBuildAttrs.cpp for Release build
llvm[3]: Compiling ARMWinEH.cpp for Release build
llvm[3]: Compiling Allocator.cpp for Release build
llvm[3]: Compiling Atomic.cpp for Release build
llvm[3]: Compiling BlockFrequency.cpp for Release build
llvm[3]: Compiling BranchProbability.cpp for Release build
llvm[3]: Compiling COM.cpp for Release build
llvm[3]: Compiling CommandLine.cpp for Release build
llvm[3]: Compiling Compression.cpp for Release build
llvm[3]: Compiling ConvertUTF.c for Release build
llvm[3]: Compiling ConvertUTFWrapper.cpp for Release build
llvm[3]: Compiling CrashRecoveryContext.cpp for Release build
llvm[3]: Compiling DAGDeltaAlgorithm.cpp for Release build
llvm[3]: Compiling DataExtractor.cpp for Release build
llvm[3]: Compiling DataStream.cpp for Release build
llvm[3]: Compiling Debug.cpp for Release build
llvm[3]: Compiling DeltaAlgorithm.cpp for Release build
llvm[3]: Compiling Dwarf.cpp for Release build
llvm[3]: Compiling DynamicLibrary.cpp for Release build
/rustc-1.8.0/src/llvm/lib/Support/DynamicLibrary.cpp: In static member function 'static void* llvm::sys::DynamicLibrary::SearchForAddressOfSymbol(const char*)':
/rustc-1.8.0/src/llvm/lib/Support/DynamicLibrary.cpp:148:21: error: invalid conversion from 'const void*' to 'void*' [-fpermissive]
     EXPLICIT_SYMBOL(stderr);
                     ^
/rustc-1.8.0/src/llvm/lib/Support/DynamicLibrary.cpp:141:43: note: in definition of macro 'EXPLICIT_SYMBOL'
    if (!strcmp(symbolName, #SYM)) return &SYM
                                           ^
/rustc-1.8.0/src/llvm/lib/Support/DynamicLibrary.cpp:149:21: error: invalid conversion from 'const void*' to 'void*' [-fpermissive]
     EXPLICIT_SYMBOL(stdout);
                     ^
/rustc-1.8.0/src/llvm/lib/Support/DynamicLibrary.cpp:141:43: note: in definition of macro 'EXPLICIT_SYMBOL'
    if (!strcmp(symbolName, #SYM)) return &SYM
                                           ^
/rustc-1.8.0/src/llvm/lib/Support/DynamicLibrary.cpp:150:21: error: invalid conversion from 'const void*' to 'void*' [-fpermissive]
     EXPLICIT_SYMBOL(stdin);
                     ^
/rustc-1.8.0/src/llvm/lib/Support/DynamicLibrary.cpp:141:43: note: in definition of macro 'EXPLICIT_SYMBOL'
    if (!strcmp(symbolName, #SYM)) return &SYM
                                           ^
rm: can't remove '/rustc-1.8.0/x86_64-unknown-linux-gnu/llvm/lib/Support/Release/DynamicLibrary.d.tmp': No such file or directory
/rustc-1.8.0/src/llvm/Makefile.rules:1524: recipe for target '/rustc-1.8.0/x86_64-unknown-linux-gnu/llvm/lib/Support/Release/DynamicLibrary.o' failed
make[3]: Leaving directory '/rustc-1.8.0/x86_64-unknown-linux-gnu/llvm/lib/Support'
make[3]: *** [/rustc-1.8.0/x86_64-unknown-linux-gnu/llvm/lib/Support/Release/DynamicLibrary.o] Error 1
/rustc-1.8.0/src/llvm/Makefile.rules:883: recipe for target 'all' failed
make[2]: Leaving directory '/rustc-1.8.0/x86_64-unknown-linux-gnu/llvm'
make[2]: *** [all] Error 1
make[1]: *** [/rustc-1.8.0/x86_64-unknown-linux-gnu/llvm/Release/bin/llvm-config] Error 2
/rustc-1.8.0/mk/llvm.mk:95: recipe for target '/rustc-1.8.0/x86_64-unknown-linux-gnu/llvm/Release/bin/llvm-config' failed
make[1]: Leaving directory '/rustc-1.8.0'
make: *** [install] Error 2
/rustc-1.8.0/mk/install.mk:22: recipe for target 'install' failed
The command '/bin/sh -c cd 'rustc-1.8.0/'   && ./configure        --enable-dist-host-only        --enable-llvm-static-stdcpp        --target='x86_64-unknown-linux-musl'        --musl-root='/usr'        --prefix='/usr'        --disable-docs        --release-channel='stable'   && make install' returned a non-zero code: 2

[frol]

@sanmai-NL Hmm. Have you read the threads and the follow-up fixes?

rust-lang/rust#28667 was fixed by introduction of codegen-tests configuration flag (in rust-lang/rust#32168), which can be switched off (!), and, in fact, it seems it should be switched off to avoid rust-lang/rust#28667 with musl libc.

Could you try to pass --disable-codegen-tests option to the ./configure?

[sanmai-NL]

That configure parameter --disable-codegen-tests was not available for stable Rust 1.8.0. I switched from master to that channel, just since I knew 1.8.0 builds okay in my personal experience. I then ran into rust-lang/rust#27254. I do not have time anymore currently, but you can try to adapt my and @antoineco's Dockerfiles further.

[frol]

Yeap, that is exactly what I have just discovered. The fix went to the beta and newer branches. 1.8.0 doesn't have it. However, both beta and master fail fast on my attempts to make them:

cfg: version 1.9.0-dev
cfg: build triple x86_64-unknown-linux-gnu
cfg: host triples x86_64-unknown-linux-gnu
cfg: target triples x86_64-unknown-linux-gnu x86_64-unknown-linux-musl
cfg: non-build target triples x86_64-unknown-linux-musl
cfg: host for x86_64-unknown-linux-gnu is x86_64
cfg: host for x86_64-unknown-linux-musl is x86_64
cfg: os for x86_64-unknown-linux-gnu is unknown-linux-gnu
cfg: os for x86_64-unknown-linux-musl is unknown-linux-musl
cfg: have good valgrind for x86_64-unknown-linux-gnu
cfg: no good valgrind for x86_64-unknown-linux-musl
cfg: using CC=gcc (CFG_CC)
cfg: disabling valgrind run-pass tests
cfg: disabling doc build (CFG_DISABLE_DOCS)
fetch: x86_64-unknown-linux-gnu/stage0/bin/rustc
determined most recent snapshot: rust-stage0-2016-03-18-235d774-linux-x86_64-1273b6b6aed421c9e40c59f366d0df6092ec0397.tar.bz2
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 17.1M  100 17.1M    0     0   570k      0  0:00:30  0:00:30 --:--:--  581k
got download with ok hash
opening snapshot dl/rust-stage0-2016-03-18-235d774-linux-x86_64-1273b6b6aed421c9e40c59f366d0df6092ec0397.tar.bz2
extracting rust-stage0/bin/rustc
make: compiler-rt
make[1]: *** No rule to make target 'triple-builtins'.  Stop.
make: *** [x86_64-unknown-linux-gnu/rt/libcompiler-rt.a] Error 2
make[1]: Entering directory '/opt/rust/src/compiler-rt'
make[1]: Leaving directory '/opt/rust/src/compiler-rt'
/opt/rust/mk/rt.mk:404: recipe for target 'x86_64-unknown-linux-gnu/rt/libcompiler-rt.a' failed

P.S. I have tried to combine all configure options from the two provided Dockerfiles and the result is always the same: the mysterious triple-builtins rule cannot be found (and I don't see it in the code either).

[rainbreak]

@frol can you share your build script?

[rainbreak]

Not sure how you're getting your triple-builtins error, but if you configure like this:

./configure --disable-codegen-tests --musl-root=/lib --enable-dist-host-only --enable-llvm-static-stdcpp --llvm-root=/usr

then you get past that and get a different error:

  FINAL-ARCHIVE: triple/builtins: /rustc-beta/x86_64-unknown-linux-gnu/rt/compiler-rt/triple/builtins/libcompiler_rt.a
make[1]: Leaving directory '/rustc-beta/src/compiler-rt'
cp: x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcompiler-rt.a
rustc: x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore
/bin/sh: x86_64-unknown-linux-gnu/stage0/bin/rustc: not found
/rustc-beta/mk/target.mk:187: recipe for target 'x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/lib/stamp.core' failed
make: *** [x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/lib/stamp.core] Error 127
/rustc-beta # ls x86_64-unknown-linux-gnu/stage0/bin/rustc 

This is because the stage 0 compiler is linked against libc:

/rustc-beta # ldd x86_64-unknown-linux-gnu/stage0/bin/rustc 
    /lib64/ld-linux-x86-64.so.2 (0x55b7f98ba000)
    libpthread.so.0 => /lib64/ld-linux-x86-64.so.2 (0x55b7f98ba000)
    librt.so.1 => /lib64/ld-linux-x86-64.so.2 (0x55b7f98ba000)
    libdl.so.2 => /lib64/ld-linux-x86-64.so.2 (0x55b7f98ba000)
    libm.so.6 => /lib64/ld-linux-x86-64.so.2 (0x55b7f98ba000)
    libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x7f78147c6000)
    libc.so.6 => /lib64/ld-linux-x86-64.so.2 (0x55b7f98ba000)
Error loading shared library ld-linux-x86-64.so.2: No such file or directory (needed by x86_64-unknown-linux-gnu/stage0/bin/rustc)
Error relocating x86_64-unknown-linux-gnu/stage0/bin/rustc: mallinfo: symbol not found
Error relocating x86_64-unknown-linux-gnu/stage0/bin/rustc: __rawmemchr: symbol not found
Error relocating x86_64-unknown-linux-gnu/stage0/bin/rustc: __register_atfork: symbol not found

[dyerti]

I got rustc building in alpine with some serious hacks:
https://gist.github.com/dyerti/0afc38e42106b8f7ed5bbff8d7430968

Hoping to use this rustc in place of the bootstrapped stage0.

[andrew-d]

Okay, I have a branch that properly builds rustc using the same hack from @dyerti (using Arch Linux's glibc to run the bootstrapped stage0). The only downside is that it doesn't appear to properly handle --target=x86_64-unknown-linux-musl; you need to pass -l static=gcc_eh to rustc for it to build. Also, the final compiler is itself not static - it's dynamically linking to musl.

I'm going to keep investigating this and see how much more I can get done :-) Another thing I want to try, instead of using Arch Linux's glibc, is this project. Ideally, we'll have the following:

• The ability to run the stage0 compiler using a proper compatibility layer
• A compiler that has both the x86_64-unknown-linux-musl and x86_64-unknown-linux-gnu targets

It would also be nice to have a statically-linked version of rustc itself...

[jirutka]

Related issue: rust-lang/rust#31322.

[frol]

I have just noticed that @jirutka has managed to prepare an Alpine Linux package for Rust: https://github.com/alpinelinux/aports/tree/master/testing/rust

# apk add \
        --no-cache \
        --repository http://dl-cdn.alpinelinux.org/alpine/edge/main \
        --repository http://dl-cdn.alpinelinux.org/alpine/edge/testing \
        rust cargo

At the moment, I have only one issue with it, it cannot build completely static binaries because of the package patch explicitly disabling static linkage:

$ rustc --target=x86_64-unknown-linux-musl ./qq.rs
$ ldd ./qq
        /lib/ld-musl-x86_64.so.1 (0x5623b42bc000)
        libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x7f4036f29000)
        libc.musl-x86_64.so.1 => /lib/ld-musl-x86_64.so.1 (0x5623b42bc000)