[MLton] Intel Mac version of MLton

[Matthew Fluet]

Thanks for the explaination.  We'll probably go with a statically-linked 
wrapper function in C, since that is what we use for many other functions. 
It's a little unfortunate to pay the two levels of indirection.

On Fri, 13 Oct 2006, John Reppy wrote:

> Looking at the assembler code, I think that I know what the problem is.  Mac 
> OS uses
> a different linking scheme for libraries, which support dynamic linking the 
> first
> time a function is called.  Basically, calling a library function like tanh 
> requires
> going through a stub function.  If you look at what gcc generates, you would 
> see
> something like:
>
>        call    L_tanh$stub
>
> ...
>
>        .section __IMPORT,__jump_table,symbol_stubs,self_modifying_code 
> +pure_instructions,5
> L_tanh$stub:
>        .indirect_symbol _tanh
>        hlt ; hlt ; hlt ; hlt ; hlt
>
> whereas mlton is just generating
>
> 	call _tanh
>
> The simple workaround is to create statically-linked wrapper functions in C 
> or you can bite the
> bullet and implement the Mach-O calling convention for external functions.
>
> 	- John
>
> On Oct 12, 2006, at 10:07 AM, Matthew Fluet wrote:
>
>> 
>>> I would guess that it is in the assembly code that you produce.  The rules 
>>> for MACH-O files are different in places than those for ELF and COFF.
>> 
>> I can believe that MACH-O is different than ELF or COFF, but I guess I 
>> would have hoped that the assembler would complain, rather than producing 
>> an object file that doesn't link.
>> 
>>> Will the flags you suggest save the asm code?
>> 
>> Yes; '-keep g' is "keep code-Generated files".
>> 
>>>> Well, its obviously a linker issue.  You could try compiling 
>>>> regression/math.sml with the options '-keep g -keep o -verbose 1'
>>>> which will save the intermediate files and print out the command line 
>>>> passed to gcc.  I would also try '-codegen c -verbose 1' to see whether 
>>>> it is a general linker problem or specific to the native codegen.
>>>> I googled for the error message, and there are a number of pages/posts 
>>>> where people report seeing the error, but I haven't found an explaination 
>>>> or a solution.
>>>> On Wed, 11 Oct 2006, John Reppy wrote:
>>>>> I did a bin/regression and got a failure (see below).
>>>>> 	- John
>>>>> <jhr at frogbat> bin/regression
>>>>> MLton MLTONVERSION (built Mon Oct 09 23:08:56 2006 on frogbat.local)
>>>>> flags = -type-check true
>>>>> testing 1
>>>>> ...
>>>>> testing math
>>>>> /usr/bin/ld: /tmp/file1D7oqw.o has external relocation entries in non- 
>>>>> writable section (__TEXT,__text) for symbols:
>>>>> _tanh
>>>>> _cosh
>>>>> _sinh
>>>>> _pow
>>>>> collect2: ld returned 1 exit status
>>>>> call to system failed with exit status 1:
>>>>> gcc -o math /tmp/filen4F46H.o /tmp/file1D7oqw.o -L/Users/jhr/Work/ 
>>>>> mlton/mlton/build/lib/self -lmlton -L/sw/lib -lgmp -lgdtoa -lm
>>>>> _______________________________________________
>>>>> MLton mailing list
>>>>> MLton at mlton.org
>>>>> http://mlton.org/mailman/listinfo/mlton
>>> 
>> 
>
>
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