Re: [MLton] Bug report (Ur/Web, ARM)

On Thu, Oct 22, 2015 at 12:46 AM, Jason Pepas <[email protected]> wrote:
> Interesting, ltrace issues an error right away and then hangs the process,
> which is killable only via 'kill -9'.
>
> here's the command:
>
> cell@pogo1$ ltrace /usr/lib/mlton/mlton-compile @MLton ram-slop 0.5 --
> /usr/lib/mlton -ar-script /usr/lib/mlton/static-library -cc gcc
> -cc-opt-quote -I/usr/lib/mlton/include -cc-opt '-O1 -fno-common' -cc-opt
> '-fno-strict-aliasing -fomit-frame-pointer -w' -link-opt '-lm -lgmp'
> -mlb-path-map /usr/lib/mlton/mlb-path-map -target-as-opt amd64 -m64
> -target-as-opt x86 -m32 -target-cc-opt alpha '-mieee -mbwx -mtune=ev6
> -mfp-rounding-mode=d' -target-cc-opt amd64 -m64 -target-cc-opt darwin
> '-I/usr/local/include
>                  -I/opt/local/include
>                  -I/sw/include' -target-cc-opt freebsd -I/usr/local/include
> -target-cc-opt netbsd -I/usr/pkg/include -target-cc-opt openbsd
> -I/usr/local/include -target-cc-opt aix -maix64 -target-cc-opt ia64 '
> -mtune=itanium2' -target-cc-opt sparc '-m32 -mcpu=v8 -Wa,-xarch=v8plusa'
> -target-cc-opt x86 '-m32
>                 -fno-strength-reduce
>                 -fschedule-insns
>                 -fschedule-insns2
>                 -malign-functions=5
>                 -malign-jumps=2
>                 -malign-loops=2' -target-link-opt amd64 -m64
> -target-link-opt alpha '-mieee -mbwx -mtune=ev6 -mfp-rounding-mode=d'
> -target-link-opt darwin ' -L/usr/local/lib' -target-link-opt freebsd
> -L/usr/local/lib/ -target-link-opt aix -maix64 -target-link-opt ia64 ''
> -target-link-opt linux -Wl,-znoexecstack -target-link-opt mingw '-lws2_32
> -lkernel32 -lpsapi -lnetapi32 -lwinmm' -target-link-opt mingw
> -Wl,--enable-stdcall-fixup -target-link-opt netbsd '-Wl,-R/usr/pkg/lib
> -L/usr/pkg/lib/' -target-link-opt openbsd -L/usr/local/lib/ -target-link-opt
> solaris '-lnsl -lsocket -lrt' -target-link-opt x86 -m32 -profile-exclude
> '\$\(SML_LIB\)'
>
>
> and here's the output:
>
> __libc_start_main(0x11a7954, 97, 0xbecc6ff4, 0x11c1970PTRACE_SINGLESTEP:
> Input/output error
> 17636 couldn't continue when handling __libc_start_main (0x9c00) at 0x9c00

Interesting.  I expect that this is just another manifestation of the
same general problem -- ARM is a different enough platform that
although it may still be linux/glibc, some things just don't work the
way they do on x86.

I'm afraid that I don't have any easy suggestions to try next.
Really, we would need to rebuild a version of mlton with debugging
support and then run it under gdb on the target platform.  But, that
would require cross compiling, since we clearly won't be able to
bootstrap on the arm system without a working mlton compiler.

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