Re: [musl] Compile gcc-12 with musl and report errors

["alice" <alice@ayaya.dev>]

On Mon Feb 13, 2023 at 1:17 PM CET, 花静云 wrote:
> Hi：
> I installed the Alpine Linux system on the x86_64 platform, and exposed a
> problem when compiling gcc 12 using musl (master branch) in this system：
> ​/usr/lib/gcc/x86_64-alpine-linux-musl/12.2.1/../../../../x86_64-alpine-linux-musl/bin/ld: d/common-outbuffer.o: in function `_D3dmd6common4file__T11FileMappingThZQq6__ctorMFNbNcxPaZSQCdQCcQBy__TQBwThZQCc':
> outbuffer.d:(.text+0x29f): undefined reference to `mmap64'
>  
> I uploaded more detailed logs to gcc_ build_ Error.log file，and other information is as follows：
> 1、linux-lts（kernel）version：6.1.10-r0
> 2、gcc version：12.2.1_git20220924-r9
> 3、binutils version：binutils-2.40-r4
> 4、musl：master branch and commit is f47a8cdd250d9163fcfb39bf4e9d813957c0b187
>
> I suspect that the error is caused by the difference of the musl code，When
> I checked musl source, I found that there was a big difference between the
> master branch code and the v1.2.3 version code. For example, a large number of
> weaks_alias were removed during the 246f1c811448f37a44b41cd8df8d0ef9736d95f4
> commit，include “weak_alias(mmap, mmap64);” in src/mman/mmap.c.

yes, as that commit says, this was intentional. code is _not_ meant to call
these *64 functions that were removed- code should unconditionally call `mmap`
and use -D_FILE_OFFSET_BITS=64 (for C) . so, gcc (the D frontend here) needs fixing.

specifically, it's libphobos/libdruntime/core/sys/posix/sys/mman.d ,

where:

 else version (CRuntime_Musl)
 {
     static if (__USE_LARGEFILE64) void* mmap64(void*, size_t, int, int, int, off_t);
     static if (__USE_FILE_OFFSET64)
         alias mmap = mmap64;
     else
         void* mmap(void*, size_t, int, int, int, off_t);
     int munmap(void*, size_t);
 }

probably does something like expose the mmap64 symbol (no idea what this code means).
maybe __USE_LARGEFILE64 has to be unset for it?

>
> I want to compile gcc 12 based on musl (master branch). and I try to apply
> the old code to the latest branch, but this seems to be not a wise choice.
> so I share this error and look forward to some suggestions from the community
> experts.
>
> I'm Looking forward to your reply,thanks.
>
> Jingyun Hua
>
>
>
>
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