Re: [Qemu-devel] qemu vs gcc4

[Avi Kivity]

Paul Brook wrote:
> On Monday 23 October 2006 09:16, Martin Guy wrote:
>   
> > > Now, gcc4 can produce code with several return instructions (with no
> > > option to turn that of, as far as I understand). You cannot cut them out,
> > > and therefore you cannot chain the simple functions.
> > >       
> > ...unless you also map return instructions within the generated
> > functions into branches to the soon-to-be-dropped final "return"? Not
> > that I know anything about qemu internals mind u...
> >     
>
> That's exactly what my gcc4 hacks do.
>
> It gets complicated because a x86 uses variable length insn encodings so you 
> don't know where insn boundaries are, and a jmp instruction is larger than a 
> ret instruction so it's not always possible to do a straight replacement.
>   

how about

void some_generated_instruction(u32 a1, u32 s2)
{
      // code
      asm volatile ( "" );
}


that will force the code to fall through to the null asm code, avoiding 
premature returns.

if the code uses 'return' explicitly, turn it to a goto just before the 
'asm volatile'.


--
error compiling committee.c: too many arguments to function