[LLVMdev] How to represent __attribute__((fastcall)) functions in the IL

Chris Lattner clattner at apple.com
Sat Oct 20 08:14:29 PDT 2012

On Oct 20, 2012, at 12:58 AM, Duncan Sands <baldrick at free.fr> wrote:

> Hi Rafael,
> On 19/10/12 18:27, Rafael EspĂ­ndola 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.


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