How to compile rust in a musl libc based linux system

[uuhan]

Hi, recently I need to compile rust in my musl libc based linux system. I download the rust's source code, configure it and make.

But it failed due to the rust/x86_64-unknown-linux-gnu/stage0/bin/rustc run failed.
It's interpreter is
/lib64/ld-linux-x86-64.so.2
but my system has just the
/lib/ld-musl-x86_64.so.1

I have already the llvm-3.5 installed, It seems to be it just lack of a runable rust stage0 binary for my system.

So, is there a STATICALLY LINKED RUST STAGE0 binary to feed my needs?
Or, how can I compile the proper stage0 rustc binary from stretch ?

[MagaTailor]

Is the musl ld compatible enough with gnu ld (and the two libc's themselves)? If so, symlinking should be sufficient.

[alexcrichton]

Yes unfortunately we only produce glibc snapshots that are dynamically linked. There are currently no statically linked snapshots of the compiler.

[nodakai]

Can you try /lib/ld-musl-x86_64.so.1 /path/to/stage0/rustc ? If successful, the rest is just shell scripting.

My understanding is it's similar to overriding a Shebang line in a shell script by explicitly calling a shell, like /bin/dash /path/to/script.sh

• http://man7.org/linux/man-pages/man8/ld.so.8.html

The .interp section in an ELF exe should serve as a "Shebang line."

[uuhan]

@petevine @nodakai Did not work. Some Symbol not found
__rawmemchr mallinfo __register_atfork

@alexcrichton Get it. : )

[nodakai]

How about referencing a pre-built glibc (eg. https://www.archlinux.org/packages/core/x86_64/glibc/ ) ? It's shipped with a dynamic loader as well.

$ strace -e file ./usr/lib/ld-linux-x86-64.so.2 --inhibit-cache --library-path ./usr/lib /bin/cat /etc/hostname 2>&1 | grep -v ENOENT
execve("./usr/lib/ld-linux-x86-64.so.2", ["./usr/lib/ld-linux-x86-64.so.2", "--inhibit-cache", "--library-path", "./usr/lib", "/bin/cat", "/etc/hostname"], [/* 52 vars */]) = 0
open("/bin/cat", O_RDONLY|O_CLOEXEC)    = 3
open("./usr/lib/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
getcwd("/tmp/myglibc", 128)             = 13
open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
open("/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 3
open("/etc/hostname", O_RDONLY)         = 3
d9+++ exited with 0 +++

(Not sure if strace(8) is reliable under such a hack.)

[jirutka]

@alexcrichton in #34687:
I know I'd personally love to see rustc running on Alpine, I've tried it once or twice in docker and have been sad when it doesn't work!

Well, obviously, because Alpine doesn’t use glibc, but musl libc, that is only partially binary compatible with glibc (musl strictly follows standards, but glibc does not). Therefore you can’t run rustc snapshot compiled against glibc on Alpine and it’s not possible to build rustc without rustc.

@alexcrichton in #34687:
Do you know if there are cross compilers from something like Ubuntu to Alpine Linux?

This is not about distributions, but different libc. So you need something to cross-compile between glibc and musl. It’s very similar to cross-compiling between different architectures.
Yes, there are such a tools, for example musl-cross.

@alexcrichton in #34687:
If we have that then the rest of the implementation should be relatively easy I believe.

I believe that it may be easy for someone skilled in cross compiling, but unfortunately me and other guys from Alpine community, who would like Rust on Alpine, are not. And those few skilled C programmers doesn’t like Rust, because… you know… C programmers…

/cc @japaric

[japaric]

I got a bash script that uses docker to cross compile a rustc for the host x86_64-unknown-linux-musl from a Ubuntu image. The rustc is a fully statically linked binary and doesn't depend on glibc because it was built against musl. The issue is that the resulting rustc segfaults when I try to compile anything ... rustc -V works though. The root of the problem appears to be LLVM but I haven't had to look into it / fix it. I have made my work so far public in the hope that someone might be able to push it to the finish line. See this i.r-l.o thread for the details.

[jirutka]

@japaric Thanks for your effort. I’ve discussed your gist in our IRC channel and skarnet recommends to use richfelker/musl-cross-make instead of GregorR/musl-cross. He said that GregorR’s musl-cross is pretty much obsoleted by richfelker’s (dalias’) musl-cross-make that is more up-to-date.

[japaric]

@jirutka Thanks for tip. I've updated the gist to use musl-cross-make instead of musl-cross. Unfortunately, it didn't magically fix the llvm issue.

[jirutka]

@japaric I’m trying to compile rustc using your script and it always fail in the last phase with:

build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-musl/lib/libunwind-40c0f24bb84d756d.rlib(UnwindLevel1.c.o): unrecognized relocation (0x2a) in section `.text.assert_rtn'
toolchain/bin/../lib/gcc/x86_64-linux-musl/5.2.0/../../../../x86_64-linux-musl/bin/ld: final link failed: Bad value

I’ve tried it with gcc 5.3.0 and 5.2.0, with and without --enable-llvm-static-stdcpp, but with no difference.

Do you have some idea what’s wrong?

[japaric]

@jirutka

I’m trying to compile rustc using your script and it always fail in the last phase with:

While building libunwind-40c0f24bb84d756d.rlib? That looks like a new error to me.

Are you following the gist instructions "to the letter"? In particular, are you using a Ubuntu 15.10 docker image? Because, IIRC, there some was some bug in the Ubuntu 16.04 binutils package that also caused a linker error (don't remember the details). That's why the instructions say: use Ubuntu 15.10.

Or it could be a recent regression in the unwind crate (doesn't seem likely to me though). Perhaps try checking out an older version of rust-lang/rust? My last test of the gist was around 6 days ago

[jupp0r]

Wouldn't it make sense for the stage0 rustc to be statically linked in general?