Re: [RFC] asm goto

[Paolo Bonzini <bonzini at gnu dot org>]

> > It *does* support arbitrary numbers of edges. You can put
> > any number of labels in that section.

I'm curious however: from reading the patch, I didn't find anything 
adding a default fallthrough edge.  Does it do that?

> > > and it needs a means to specify the exit block/exceptions.
> >
> > Hmm?
>
> What if I want to say that the asm might throw an exception? That
> requires an edge to the exit block.

You can add a label and throw there, like:

#define JO	_JO(__COUNTER__)

#define_JO(N) \
{ \
  register char *foo asm("%rax"); \
  if (1) \
    asm goto ("mov %0, %%rax; jo %l0" : : "a" ("overflow") : : \
             throw##N); \
  else throw##N: throw overflow_exception(foo); \
}

Paolo