PATCH: mips16 function attributes, version N+1

Nigel Stephens nigel@mips.com
Mon Sep 3 10:28:00 GMT 2007



Richard Sandiford wrote:
>> I tried this, and yes, it does cause about half a dozen of the tls tests 
>> to fail with -mflip-mips16.  Rather than trying to mess with 
>> conditionalizing those, how about if I just leave the sorry message in, 
>> and document that this is one of the things that doesn't work yet?  In 
>> extend.texi I've already written:
>>
>>    Mixed MIPS16 and non-MIPS16 code may interact badly with some GCC
>>    extensions such as @code{__builtin_apply} (@pxref{Constructing
>>    Calls}).
>>
>> so I could just add:
>>
>>    and thread-local variables (@pxref{Thread-Local}).
>>     
>
> My understanding is that __builtin_apply is only going to be troublesome
> for calls between non-MIPS16 and MIPS16 hard-float code.  Each side is
> abiding by the correct ABI for its own mode, but the linker's stubs
> support can't help us.  Although it is of course a solvable problem,
> it's not a particularly worrying one, since __builtin_apply is one of
> those things we keep meaning to get rid of...
>
> TLS is different because emultls is not supposed to be used for MIPS
> at all.  

Although it shouldn't be required for Linux configurations, I imagine 
that it could be useful to support emutls for bare-iron /RTOS 
configurations. But it's a new feature for SDE and not yet on the 
required feature list, so this is something that we can revisit at a 
later date.


Nigel



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