llvm dev - Oct 2012 - [LLVMdev] How to represent __attribute__((fastcall)) functions in the IL

On Oct 20, 2012, at 12:58 AM, Duncan Sands <baldrick at free.fr> wrote:
> Hi Rafael,
> 
> On 19/10/12 18:27, Rafael Espíndola wrote:
>>> Don't get me wrong, I don't have any good ideas about how
to do this, I'm
>>> just hoping someone does. End result might allow something like:
>>> 
>>> declare void @foo(double inreg <eax,edx> %x)
>> 
>> Not sure I would go all the way to specifying registers in the IL
>> (although I liked it at some point). What I like most right now is
>> something along the lines of
>> http://llvm.org/pr12193. That makes it explicit if something is on the
>> stack or in registers and that information is correct for both the
>> caller and callee. What is left for codegen is counting the  register
>> arguments and computing stack offsets.
> 
> I'm 100% in favour of having "onstack" as a complement to
"inreg".  I'm
> not so happy about the more funky changes you suggested in the PR, namely
> having the callee no longer match the caller, but "onstack"
itself makes
> a lot of sense to me.
Makes a lot of sense to me too.

-Chris

>>> Not sure I would go all the way to specifying registers in the IL
>>> (although I liked it at some point). What I like most right now is
>>> something along the lines of
>>> http://llvm.org/pr12193. That makes it explicit if something is on
the
>>> stack or in registers and that information is correct for both the
>>> caller and callee. What is left for codegen is counting the 
register
>>> arguments and computing stack offsets.
>>
>> I'm 100% in favour of having "onstack" as a complement to
"inreg".  I'm
>> not so happy about the more funky changes you suggested in the PR,
namely
>> having the callee no longer match the caller, but "onstack"
itself makes
>> a lot of sense to me.
>
> Makes a lot of sense to me too.
It is way too late for a formal for a BOF, but maybe we could meet
during the hacker lab to discuss onstack, explicit regs, and other
ideas regarding how to represent calling conventions?
> -Chris
Cheers,
Rafael

On Oct 21, 2012, at 5:53 PM, Rafael Espíndola <rafael.espindola at
gmail.com> wrote:
>>>> Not sure I would go all the way to specifying registers in the
IL
>>>> (although I liked it at some point). What I like most right now
is
>>>> something along the lines of
>>>> http://llvm.org/pr12193. That makes it explicit if something is
on the
>>>> stack or in registers and that information is correct for both
the
>>>> caller and callee. What is left for codegen is counting the 
register
>>>> arguments and computing stack offsets.
>>> 
>>> I'm 100% in favour of having "onstack" as a
complement to "inreg".  I'm
>>> not so happy about the more funky changes you suggested in the PR,
namely
>>> having the callee no longer match the caller, but
"onstack" itself makes
>>> a lot of sense to me.
>> 
>> Makes a lot of sense to me too.
> 
> It is way too late for a formal for a BOF, but maybe we could meet
> during the hacker lab to discuss onstack, explicit regs, and other
> ideas regarding how to represent calling conventions?
Sure, sounds good.  There is also a rumor that the devmtg may have an
"UnBOF" section, which is specifically for organized-on-demand BOF
like content.  More details to come,

-Chris