llvm dev - Dec 2016 - Strange clang behavior when compiled against musl

I have managed to compile llvm and clang against musl, but it behaves really
strange:

At first I tried to launch the compiler with musl dynamic loader:

    $ LD_LIBRARY_PATH=/path/to/musl/lib /path/to/musl/lib/ld-musl-x86_64.so.1
/path/to/llvm/bin/clang -v
    clang version 4.0.0 (https://github.com/llvm-mirror/clang
40adebeca0f99006d407508653c2cbd270a1a51c) (https://github.com/llvm-mirror/llvm
943496ffc4e7cb9d7dd6f5119325a7583e2cc31f)
    Target: x86_64-pc-linux-musl
    Thread model: posix
    InstalledDir: /path/to/llvm/bin

It worked, but couldn't compile binaries:

    $ LD_LIBRARY_PATH=/path/to/musl/lib /path/to/musl/lib/ld-musl-x86_64.so.1
/path/to/llvm/bin/clang -v -c hello.c
    clang version 4.0.0 (https://github.com/llvm-mirror/clang
40adebeca0f99006d407508653c2cbd270a1a51c) (https://github.com/llvm-mirror/llvm
943496ffc4e7cb9d7dd6f5119325a7583e2cc31f)
    Target: x86_64-pc-linux-musl
    Thread model: posix
    InstalledDir: /path/to/llvm/bin
     "/path/to/musl/lib/ld-musl-x86_64.so.1" -cc1 -triple
x86_64-pc-linux-musl -emit-obj -mrelax-all -disable-free -disable-llvm-verifier
-discard-value-names -main-file-name hello.c -mrelocation-model static
-mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose
-mconstructor-aliases -munwind-tables -target-cpu x86-64 -v -dwarf-column-info
-debugger-tuning=gdb -coverage-notes-file /path/to/hello/hello.gcno
-resource-dir /path/to/musl/lib/clang/4.0.0 -isysroot /path/to/musl
-internal-isystem /path/to/musl/usr/local/include -internal-isystem
/path/to/musl/lib/clang/4.0.0/include -internal-externc-isystem
/path/to/musl/include -internal-externc-isystem /path/to/musl/usr/include
-fdebug-compilation-dir /path/to/hello -ferror-limit 19 -fmessage-length 80
-fobjc-runtime=gcc -fdiagnostics-show-option -o hello.o -x c hello.c
    /path/to/musl/lib/ld-musl-x86_64.so.1: cannot load -cc1: No such file or
directory

As you can see it is trying to execute a compilation command with omitted clang
binary path.

So I thought that it would work in chroot with nothing but musl and clang in it.
So I chrooted to a newly created directory, put musl and clang in it, and it
still didn't work:

    (chroot)$ clang -v -I/include -c hello.c
    clang version 4.0.0 (https://github.com/llvm-mirror/clang
40adebeca0f99006d407508653c2cbd270a1a51c) (https://github.com/llvm-mirror/llvm
943496ffc4e7cb9d7dd6f5119325a7583e2cc31f)
    Target: x86_64-pc-linux-musl
    Thread model: posix
    InstalledDir: /bin
     "" -cc1 -triple x86_64-pc-linux-musl -emit-obj -mrelax-all
-disable-free -disable-llvm-verifier -discard-value-names -main-file-name
hello.c -mrelocation-model static -mthread-model posix -mdisable-fp-elim
-fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -target-cpu
x86-64 -v -dwarf-column-info -debugger-tuning=gdb -coverage-notes-file
/hello/hello.gcno -resource-dir ../lib/clang/4.0.0 -I /include -isysroot
/path/to/musl -internal-isystem /path/to/musl/usr/local/include
-internal-isystem ../lib/clang/4.0.0/include -internal-externc-isystem
/path/to/musl/include -internal-externc-isystem /path/to/musl/usr/include
-fdebug-compilation-dir /hello -ferror-limit 19 -fmessage-length 139
-fobjc-runtime=gcc -fdiagnostics-show-option -o hello.o -x c hello.c
    error: unable to execute command: Executable "" doesn't exist!

So it still doesn't launch clang as it should. But if I just copy and paste
the produced line replacing `""` with `clang` it works and produces
fine object file.

What else can I try to make it work? Does clang have public bugzilla?

Where can I send my musl support patches?

Clang uses this logic in llvm/lib/Support/Unix/Path.inc to find itself (
https://github.com/llvm-mirror/llvm/blob/84d1e9104a43f9940a76467d58156ade4b1c8d52/lib/Support/Unix/Path.inc#L170
):

...
#elif defined(__linux__) || defined(__CYGWIN__)
  char exe_path[MAXPATHLEN];
  StringRef aPath("/proc/self/exe");
  if (sys::fs::exists(aPath)) {
      // /proc is not always mounted under Linux (chroot for example).
      ssize_t len = readlink(aPath.str().c_str(), exe_path,
sizeof(exe_path));
      if (len >= 0)
          return std::string(exe_path, len);
  } else {
      // Fall back to the classical detection.
      if (getprogpath(exe_path, argv0))
        return exe_path;
  }
#elif defined(HAVE_DLFCN_H)
...

Presumably we are hitting the else, which would explain the bad behavior in
the first example, where clang uses the musl loader for the -cc1 action. I
don't know what went wrong in the chroot.

You can send patches to llvm-commits at lists.llvm.org and file bugs at
http://llvm.org/bugs.

Thanks for looking into this!

On Fri, Dec 9, 2016 at 1:42 AM, Dmitry Golovin via cfe-dev <
cfe-dev at lists.llvm.org> wrote:
> I have managed to compile llvm and clang against musl, but it behaves
> really strange:
>
> At first I tried to launch the compiler with musl dynamic loader:
>
>     $ LD_LIBRARY_PATH=/path/to/musl/lib
/path/to/musl/lib/ld-musl-x86_64.so.1
> /path/to/llvm/bin/clang -v
>     clang version 4.0.0 (https://github.com/llvm-mirror/clang
> 40adebeca0f99006d407508653c2cbd270a1a51c) (https://github.com/llvm-
> mirror/llvm 943496ffc4e7cb9d7dd6f5119325a7583e2cc31f)
>     Target: x86_64-pc-linux-musl
>     Thread model: posix
>     InstalledDir: /path/to/llvm/bin
>
> It worked, but couldn't compile binaries:
>
>     $ LD_LIBRARY_PATH=/path/to/musl/lib
/path/to/musl/lib/ld-musl-x86_64.so.1
> /path/to/llvm/bin/clang -v -c hello.c
>     clang version 4.0.0 (https://github.com/llvm-mirror/clang
> 40adebeca0f99006d407508653c2cbd270a1a51c) (https://github.com/llvm-
> mirror/llvm 943496ffc4e7cb9d7dd6f5119325a7583e2cc31f)
>     Target: x86_64-pc-linux-musl
>     Thread model: posix
>     InstalledDir: /path/to/llvm/bin
>      "/path/to/musl/lib/ld-musl-x86_64.so.1" -cc1 -triple
> x86_64-pc-linux-musl -emit-obj -mrelax-all -disable-free
> -disable-llvm-verifier -discard-value-names -main-file-name hello.c
> -mrelocation-model static -mthread-model posix -mdisable-fp-elim
> -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables
> -target-cpu x86-64 -v -dwarf-column-info -debugger-tuning=gdb
> -coverage-notes-file /path/to/hello/hello.gcno -resource-dir
> /path/to/musl/lib/clang/4.0.0 -isysroot /path/to/musl -internal-isystem
> /path/to/musl/usr/local/include -internal-isystem
> /path/to/musl/lib/clang/4.0.0/include -internal-externc-isystem
> /path/to/musl/include -internal-externc-isystem /path/to/musl/usr/include
> -fdebug-compilation-dir /path/to/hello -ferror-limit 19 -fmessage-length 80
> -fobjc-runtime=gcc -fdiagnostics-show-option -o hello.o -x c hello.c
>     /path/to/musl/lib/ld-musl-x86_64.so.1: cannot load -cc1: No such file
> or directory
>
> As you can see it is trying to execute a compilation command with omitted
> clang binary path.
>
> So I thought that it would work in chroot with nothing but musl and clang
> in it. So I chrooted to a newly created directory, put musl and clang in
> it, and it still didn't work:
>
>     (chroot)$ clang -v -I/include -c hello.c
>     clang version 4.0.0 (https://github.com/llvm-mirror/clang
> 40adebeca0f99006d407508653c2cbd270a1a51c) (https://github.com/llvm-
> mirror/llvm 943496ffc4e7cb9d7dd6f5119325a7583e2cc31f)
>     Target: x86_64-pc-linux-musl
>     Thread model: posix
>     InstalledDir: /bin
>      "" -cc1 -triple x86_64-pc-linux-musl -emit-obj -mrelax-all
> -disable-free -disable-llvm-verifier -discard-value-names -main-file-name
> hello.c -mrelocation-model static -mthread-model posix -mdisable-fp-elim
> -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables
> -target-cpu x86-64 -v -dwarf-column-info -debugger-tuning=gdb
> -coverage-notes-file /hello/hello.gcno -resource-dir ../lib/clang/4.0.0 -I
> /include -isysroot /path/to/musl -internal-isystem
/path/to/musl/usr/local/include
> -internal-isystem ../lib/clang/4.0.0/include -internal-externc-isystem
> /path/to/musl/include -internal-externc-isystem /path/to/musl/usr/include
> -fdebug-compilation-dir /hello -ferror-limit 19 -fmessage-length 139
> -fobjc-runtime=gcc -fdiagnostics-show-option -o hello.o -x c hello.c
>     error: unable to execute command: Executable "" doesn't
exist!
>
> So it still doesn't launch clang as it should. But if I just copy and
> paste the produced line replacing `""` with `clang` it works and
produces
> fine object file.
>
> What else can I try to make it work? Does clang have public bugzilla?
>
> Where can I send my musl support patches?
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>
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Try removing "/path/to/musl/lib/ld-musl-x86_64.so.1" from the
invocation
and see if that helps:

$ LD_LIBRARY_PATH=/path/to/musl/lib /path/to/musl/lib/ld-musl-x86_64.so.1
/path/to/llvm/bin/clang -v

because the shell thinks you want to run
""/path/to/musl/lib/ld-musl-x86_64.so.1"
not "/path/to/llvm/bin/clang"

hth...
don



On Fri, Dec 9, 2016 at 1:42 AM, Dmitry Golovin via cfe-dev <
cfe-dev at lists.llvm.org> wrote:
> I have managed to compile llvm and clang against musl, but it behaves
> really strange:
>
> At first I tried to launch the compiler with musl dynamic loader:
>
>     $ LD_LIBRARY_PATH=/path/to/musl/lib
/path/to/musl/lib/ld-musl-x86_64.so.1
> /path/to/llvm/bin/clang -v
>     clang version 4.0.0 (https://github.com/llvm-mirror/clang
> 40adebeca0f99006d407508653c2cbd270a1a51c) (https://github.com/llvm-
> mirror/llvm 943496ffc4e7cb9d7dd6f5119325a7583e2cc31f)
>     Target: x86_64-pc-linux-musl
>     Thread model: posix
>     InstalledDir: /path/to/llvm/bin
>
> It worked, but couldn't compile binaries:
>
>     $ LD_LIBRARY_PATH=/path/to/musl/lib
/path/to/musl/lib/ld-musl-x86_64.so.1
> /path/to/llvm/bin/clang -v -c hello.c
>     clang version 4.0.0 (https://github.com/llvm-mirror/clang
> 40adebeca0f99006d407508653c2cbd270a1a51c) (https://github.com/llvm-
> mirror/llvm 943496ffc4e7cb9d7dd6f5119325a7583e2cc31f)
>     Target: x86_64-pc-linux-musl
>     Thread model: posix
>     InstalledDir: /path/to/llvm/bin
>      "/path/to/musl/lib/ld-musl-x86_64.so.1" -cc1 -triple
> x86_64-pc-linux-musl -emit-obj -mrelax-all -disable-free
> -disable-llvm-verifier -discard-value-names -main-file-name hello.c
> -mrelocation-model static -mthread-model posix -mdisable-fp-elim
> -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables
> -target-cpu x86-64 -v -dwarf-column-info -debugger-tuning=gdb
> -coverage-notes-file /path/to/hello/hello.gcno -resource-dir
> /path/to/musl/lib/clang/4.0.0 -isysroot /path/to/musl -internal-isystem
> /path/to/musl/usr/local/include -internal-isystem
> /path/to/musl/lib/clang/4.0.0/include -internal-externc-isystem
> /path/to/musl/include -internal-externc-isystem /path/to/musl/usr/include
> -fdebug-compilation-dir /path/to/hello -ferror-limit 19 -fmessage-length 80
> -fobjc-runtime=gcc -fdiagnostics-show-option -o hello.o -x c hello.c
>     /path/to/musl/lib/ld-musl-x86_64.so.1: cannot load -cc1: No such file
> or directory
>
> As you can see it is trying to execute a compilation command with omitted
> clang binary path.
>
> So I thought that it would work in chroot with nothing but musl and clang
> in it. So I chrooted to a newly created directory, put musl and clang in
> it, and it still didn't work:
>
>     (chroot)$ clang -v -I/include -c hello.c
>     clang version 4.0.0 (https://github.com/llvm-mirror/clang
> 40adebeca0f99006d407508653c2cbd270a1a51c) (https://github.com/llvm-
> mirror/llvm 943496ffc4e7cb9d7dd6f5119325a7583e2cc31f)
>     Target: x86_64-pc-linux-musl
>     Thread model: posix
>     InstalledDir: /bin
>      "" -cc1 -triple x86_64-pc-linux-musl -emit-obj -mrelax-all
> -disable-free -disable-llvm-verifier -discard-value-names -main-file-name
> hello.c -mrelocation-model static -mthread-model posix -mdisable-fp-elim
> -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables
> -target-cpu x86-64 -v -dwarf-column-info -debugger-tuning=gdb
> -coverage-notes-file /hello/hello.gcno -resource-dir ../lib/clang/4.0.0 -I
> /include -isysroot /path/to/musl -internal-isystem
/path/to/musl/usr/local/include
> -internal-isystem ../lib/clang/4.0.0/include -internal-externc-isystem
> /path/to/musl/include -internal-externc-isystem /path/to/musl/usr/include
> -fdebug-compilation-dir /hello -ferror-limit 19 -fmessage-length 139
> -fobjc-runtime=gcc -fdiagnostics-show-option -o hello.o -x c hello.c
>     error: unable to execute command: Executable "" doesn't
exist!
>
> So it still doesn't launch clang as it should. But if I just copy and
> paste the produced line replacing `""` with `clang` it works and
produces
> fine object file.
>
> What else can I try to make it work? Does clang have public bugzilla?
>
> Where can I send my musl support patches?
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>
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Actually, the problem is the *if* part. If you invoke the loader as the
binary name, /proc/self/exe returns the path to the loader, not the path to
clang.

E.g.:

$ /bin/ls -l /proc/self/exe
lrwxrwxrwx 1 jyknight eng 0 Dec  9 12:49 /proc/self/exe -> /bin/ls

$ /lib64/ld-linux-x86-64.so.2 /bin/ls -l /proc/self/exe
lrwxrwxrwx 1 jyknight eng 0 Dec  9 12:49 /proc/self/exe ->
/lib/x86_64-linux-gnu/ld-2.19.so

Further, even if it *DID* return the path to the clang binary, you'd still
be in trouble, since the exec would then bypass your loader choice when
invoking the subprocess.

I'd suggest running patchelf to change the interpreter embedded in the
binary, if that's what you need to do, instead of running the loader
manually.


On Fri, Dec 9, 2016 at 11:32 AM, Reid Kleckner via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Clang uses this logic in llvm/lib/Support/Unix/Path.inc to find itself (
> https://github.com/llvm-mirror/llvm/blob/84d1e9104a43f9940a76467d58156a
> de4b1c8d52/lib/Support/Unix/Path.inc#L170):
>
> ...
> #elif defined(__linux__) || defined(__CYGWIN__)
>   char exe_path[MAXPATHLEN];
>   StringRef aPath("/proc/self/exe");
>   if (sys::fs::exists(aPath)) {
>       // /proc is not always mounted under Linux (chroot for example).
>       ssize_t len = readlink(aPath.str().c_str(), exe_path,
> sizeof(exe_path));
>       if (len >= 0)
>           return std::string(exe_path, len);
>   } else {
>       // Fall back to the classical detection.
>       if (getprogpath(exe_path, argv0))
>         return exe_path;
>   }
> #elif defined(HAVE_DLFCN_H)
> ...
>
> Presumably we are hitting the else, which would explain the bad behavior
> in the first example, where clang uses the musl loader for the -cc1 action.
> I don't know what went wrong in the chroot.
>
> You can send patches to llvm-commits at lists.llvm.org and file bugs at
> http://llvm.org/bugs.
>
> Thanks for looking into this!
>
> On Fri, Dec 9, 2016 at 1:42 AM, Dmitry Golovin via cfe-dev <
> cfe-dev at lists.llvm.org> wrote:
>
>> I have managed to compile llvm and clang against musl, but it behaves
>> really strange:
>>
>> At first I tried to launch the compiler with musl dynamic loader:
>>
>>     $ LD_LIBRARY_PATH=/path/to/musl/lib
/path/to/musl/lib/ld-musl-x86_64.so.1
>> /path/to/llvm/bin/clang -v
>>     clang version 4.0.0 (https://github.com/llvm-mirror/clang
>> 40adebeca0f99006d407508653c2cbd270a1a51c)
(https://github.com/llvm-mirro
>> r/llvm 943496ffc4e7cb9d7dd6f5119325a7583e2cc31f)
>>     Target: x86_64-pc-linux-musl
>>     Thread model: posix
>>     InstalledDir: /path/to/llvm/bin
>>
>> It worked, but couldn't compile binaries:
>>
>>     $ LD_LIBRARY_PATH=/path/to/musl/lib
/path/to/musl/lib/ld-musl-x86_64.so.1
>> /path/to/llvm/bin/clang -v -c hello.c
>>     clang version 4.0.0 (https://github.com/llvm-mirror/clang
>> 40adebeca0f99006d407508653c2cbd270a1a51c)
(https://github.com/llvm-mirro
>> r/llvm 943496ffc4e7cb9d7dd6f5119325a7583e2cc31f)
>>     Target: x86_64-pc-linux-musl
>>     Thread model: posix
>>     InstalledDir: /path/to/llvm/bin
>>      "/path/to/musl/lib/ld-musl-x86_64.so.1" -cc1 -triple
>> x86_64-pc-linux-musl -emit-obj -mrelax-all -disable-free
>> -disable-llvm-verifier -discard-value-names -main-file-name hello.c
>> -mrelocation-model static -mthread-model posix -mdisable-fp-elim
>> -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables
>> -target-cpu x86-64 -v -dwarf-column-info -debugger-tuning=gdb
>> -coverage-notes-file /path/to/hello/hello.gcno -resource-dir
>> /path/to/musl/lib/clang/4.0.0 -isysroot /path/to/musl -internal-isystem
>> /path/to/musl/usr/local/include -internal-isystem
>> /path/to/musl/lib/clang/4.0.0/include -internal-externc-isystem
>> /path/to/musl/include -internal-externc-isystem
/path/to/musl/usr/include
>> -fdebug-compilation-dir /path/to/hello -ferror-limit 19
-fmessage-length 80
>> -fobjc-runtime=gcc -fdiagnostics-show-option -o hello.o -x c hello.c
>>     /path/to/musl/lib/ld-musl-x86_64.so.1: cannot load -cc1: No such
>> file or directory
>>
>> As you can see it is trying to execute a compilation command with
omitted
>> clang binary path.
>>
>> So I thought that it would work in chroot with nothing but musl and
clang
>> in it. So I chrooted to a newly created directory, put musl and clang
in
>> it, and it still didn't work:
>>
>>     (chroot)$ clang -v -I/include -c hello.c
>>     clang version 4.0.0 (https://github.com/llvm-mirror/clang
>> 40adebeca0f99006d407508653c2cbd270a1a51c)
(https://github.com/llvm-mirro
>> r/llvm 943496ffc4e7cb9d7dd6f5119325a7583e2cc31f)
>>     Target: x86_64-pc-linux-musl
>>     Thread model: posix
>>     InstalledDir: /bin
>>      "" -cc1 -triple x86_64-pc-linux-musl -emit-obj
-mrelax-all
>> -disable-free -disable-llvm-verifier -discard-value-names
-main-file-name
>> hello.c -mrelocation-model static -mthread-model posix
-mdisable-fp-elim
>> -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables
>> -target-cpu x86-64 -v -dwarf-column-info -debugger-tuning=gdb
>> -coverage-notes-file /hello/hello.gcno -resource-dir ../lib/clang/4.0.0
-I
>> /include -isysroot /path/to/musl -internal-isystem
>> /path/to/musl/usr/local/include -internal-isystem
>> ../lib/clang/4.0.0/include -internal-externc-isystem
/path/to/musl/include
>> -internal-externc-isystem /path/to/musl/usr/include
-fdebug-compilation-dir
>> /hello -ferror-limit 19 -fmessage-length 139 -fobjc-runtime=gcc
>> -fdiagnostics-show-option -o hello.o -x c hello.c
>>     error: unable to execute command: Executable ""
doesn't exist!
>>
>> So it still doesn't launch clang as it should. But if I just copy
and
>> paste the produced line replacing `""` with `clang` it works
and produces
>> fine object file.
>>
>> What else can I try to make it work? Does clang have public bugzilla?
>>
>> Where can I send my musl support patches?
>> _______________________________________________
>> cfe-dev mailing list
>> cfe-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>
>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
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<div>No, it doesn't help. It was my first thought as well, so tried to
invoke clang inside chroot environment (I described it in the second part of my
original message), but all I got
was:</div><div> </div><div>error: unable to execute
command: Executable "" doesn't
exist!</div><div> </div><div>Regards,</div><div>Dmitry</div><div><br
/></div><div><br /></div><div>09.12.2016,
19:45, "don hinton"
<hintonda@gmail.com>:</div><blockquote
type="cite"><div dir="ltr"><div><span
style="font-size:12.8px;">Try removing "</span><span
style="font-size:12.8px;">/path/to/musl/lib/ld-musl-x86_</span><wbr
style="font-size:12.8px;" /><span
style="font-size:12.8px;">64.so.1" from the invocation and see
if that helps:</span></div><span
style="font-size:12.8px;"><div><span
style="font-size:12.8px;"><br /></span></div>$
LD_LIBRARY_PATH=/path/to/musl/</span><wbr
style="font-size:12.8px;" /><span
style="font-size:12.8px;">lib
/path/to/musl/lib/ld-musl-x86_</span><wbr
style="font-size:12.8px;" /><span
style="font-size:12.8px;">64.so.1 /path/to/llvm/bin/clang
-v</span><br /><div><span
style="font-size:12.8px;"><br
/></span></div><div><span
style="font-size:12.8px;">because the shell thinks you want to run
"</span><span
style="font-size:12.8px;">"</span><span
style="font-size:12.8px;">/path/to/musl/lib/ld-musl-x86_</span><wbr
style="font-size:12.8px;" /><span
style="font-size:12.8px;">64.so.1" not
"</span><span
style="font-size:12.8px;">/path/to/llvm/bin/clang"</span></div><div><span
style="font-size:12.8px;"><br
/></span></div><div><span
style="font-size:12.8px;">hth...</span></div><div><span
style="font-size:12.8px;">don</span></div><div><span
style="font-size:12.8px;"><br
/></span></div><div><span
style="font-size:12.8px;"><br
/></span></div></div><div><br /><div>On
Fri, Dec 9, 2016 at 1:42 AM, Dmitry Golovin via cfe-dev <span
dir="ltr"><<a href="mailto:cfe-dev@lists.llvm.org"
target="_blank">cfe-dev@lists.llvm.org</a>></span>
wrote:<br /><blockquote style="margin:0 0 0 0.8ex;border-left:1px
#ccc solid;padding-left:1ex;">I have managed to compile llvm and clang
against musl, but it behaves really strange:<br />
<br />
At first I tried to launch the compiler with musl dynamic loader:<br />
<br />
    $ LD_LIBRARY_PATH=/path/to/musl/<wbr />lib
/path/to/musl/lib/ld-musl-x86_<wbr />64.so.1 /path/to/llvm/bin/clang
-v<br />
    clang version 4.0.0 (<a
href="https://github.com/llvm-mirror/clang" rel="noreferrer"
target="_blank">https://github.com/llvm-<wbr
/>mirror/clang</a>
40adebeca0f99006d<span>407508653</span>c2cb<wbr />d270a1a51c)
(<a href="https://github.com/llvm-mirror/llvm"
rel="noreferrer"
target="_blank">https://github.com/llvm-<wbr
/>mirror/llvm</a>
943496ffc4e7cb9d7dd6f<span>5119325</span>a7<wbr
/>583e2cc31f)<br />
    Target: x86_64-pc-linux-musl<br />
    Thread model: posix<br />
    InstalledDir: /path/to/llvm/bin<br />
<br />
It worked, but couldn't compile binaries:<br />
<br />
    $ LD_LIBRARY_PATH=/path/to/musl/<wbr />lib
/path/to/musl/lib/ld-musl-x86_<wbr />64.so.1 /path/to/llvm/bin/clang -v -c
hello.c<br />
    clang version 4.0.0 (<a
href="https://github.com/llvm-mirror/clang" rel="noreferrer"
target="_blank">https://github.com/llvm-<wbr
/>mirror/clang</a>
40adebeca0f99006d<span>407508653</span>c2cb<wbr />d270a1a51c)
(<a href="https://github.com/llvm-mirror/llvm"
rel="noreferrer"
target="_blank">https://github.com/llvm-<wbr
/>mirror/llvm</a>
943496ffc4e7cb9d7dd6f<span>5119325</span>a7<wbr
/>583e2cc31f)<br />
    Target: x86_64-pc-linux-musl<br />
    Thread model: posix<br />
    InstalledDir: /path/to/llvm/bin<br />
     "/path/to/musl/lib/ld-musl-<wbr />x86_64.so.1" -cc1 -triple
x86_64-pc-linux-musl -emit-obj -mrelax-all -disable-free -disable-llvm-verifier
-discard-value-names -main-file-name hello.c -mrelocation-model static
-mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose
-mconstructor-aliases -munwind-tables -target-cpu x86-64 -v -dwarf-column-info
-debugger-tuning=gdb -coverage-notes-file /path/to/hello/hello.gcno
-resource-dir /path/to/musl/lib/clang/4.0.0 -isysroot /path/to/musl
-internal-isystem /path/to/musl/usr/local/<wbr />include -internal-isystem
/path/to/musl/lib/clang/4.0.0/<wbr />include -internal-externc-isystem
/path/to/musl/include -internal-externc-isystem /path/to/musl/usr/include
-fdebug-compilation-dir /path/to/hello -ferror-limit 19 -fmessage-length 80
-fobjc-runtime=gcc -fdiagnostics-show-option -o hello.o -x c hello.c<br />
    /path/to/musl/lib/ld-musl-x86_<wbr />64.so.1: cannot load -cc1: No
such file or directory<br />
<br />
As you can see it is trying to execute a compilation command with omitted clang
binary path.<br />
<br />
So I thought that it would work in chroot with nothing but musl and clang in it.
So I chrooted to a newly created directory, put musl and clang in it, and it
still didn't work:<br />
<br />
    (chroot)$ clang -v -I/include -c hello.c<br />
    clang version 4.0.0 (<a
href="https://github.com/llvm-mirror/clang" rel="noreferrer"
target="_blank">https://github.com/llvm-<wbr
/>mirror/clang</a>
40adebeca0f99006d<span>407508653</span>c2cb<wbr />d270a1a51c)
(<a href="https://github.com/llvm-mirror/llvm"
rel="noreferrer"
target="_blank">https://github.com/llvm-<wbr
/>mirror/llvm</a>
943496ffc4e7cb9d7dd6f<span>5119325</span>a7<wbr
/>583e2cc31f)<br />
    Target: x86_64-pc-linux-musl<br />
    Thread model: posix<br />
    InstalledDir: /bin<br />
     "" -cc1 -triple x86_64-pc-linux-musl -emit-obj -mrelax-all
-disable-free -disable-llvm-verifier -discard-value-names -main-file-name
hello.c -mrelocation-model static -mthread-model posix -mdisable-fp-elim
-fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -target-cpu
x86-64 -v -dwarf-column-info -debugger-tuning=gdb -coverage-notes-file
/hello/hello.gcno -resource-dir ../lib/clang/4.0.0 -I /include -isysroot
/path/to/musl -internal-isystem /path/to/musl/usr/local/<wbr />include
-internal-isystem ../lib/clang/4.0.0/include -internal-externc-isystem
/path/to/musl/include -internal-externc-isystem /path/to/musl/usr/include
-fdebug-compilation-dir /hello -ferror-limit 19 -fmessage-length 139
-fobjc-runtime=gcc -fdiagnostics-show-option -o hello.o -x c hello.c<br />
    error: unable to execute command: Executable "" doesn't
exist!<br />
<br />
So it still doesn't launch clang as it should. But if I just copy and paste
the produced line replacing `""` with `clang` it works and produces
fine object file.<br />
<br />
What else can I try to make it work? Does clang have public bugzilla?<br
/>
<br />
Where can I send my musl support patches?<br />
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</blockquote></div><br /></div>
</blockquote>