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Re: [RFC] Introducing MIPS O32 ABI Extension for FR0 and FR1 Interlinking

Matthew Fortune <> writes:
>> > Sorry, forgot about that.  In that case maybe program headers would be
>> > best, like you say.  I.e. we could use a combination of GNU attributes
>> > and a new program header, with the program header hopefully being more
>> > general than for just this case.  I suppose this comes back to the
>> > thread from binutils@ last year about how to manage the dwindling
>> > number of free flags:
>> >
>> >
>> >  to
>> >
> There are a couple of issues to resolve in order to use gnu attributes
> to record FP requirements at the module level. As it currently stands
> gnu attributes are controlled via the .gnu_attribute directive and these
> are emitted explicitly by the compiler. I think it is important that a
> more meaningful directive is available but it will need to interact
> nicely with the .gnu_attribute as well.
> The first problem is that there will be new ways to influence whether a
> gnu attribute is emitted or not. i.e. the command line options -mfp32,
> -mfpxx, -mfp64 will infer the relevant attribute Tag_GNU_MIPS_ABI_FP and
> if the .module directive is present then that would override it. Will
> there be any problems with a new ways to generate a gnu attribute?

I think we should just give an error if any .gnu_attributes are inconsistent
with the module-level setting (whether that comes from .module or command-line

> The second problem is that in order to support relaxing a mode
> requirement then any up-front directive/command line option that sets a
> specific fp32/fp64 requirement needs to be updated to fpxx. With gnu
> attributes this would mean updating an existing Tag_GNU_MIPS_ABI_FP
> setting to be modeless.

Not sure what you mean here, sorry.


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