Re: Weird behavior of nested functions

[Marco Gerards]

Jeroen Dekkers <address@hidden> writes:

> On Mon, Nov 10, 2003 at 10:10:52AM +0100, Yoshinori K. Okuji wrote:
> > On Monday 10 November 2003 00:11, Marco Gerards wrote:
> > > Is it possible that some object files for the utils and pupa mix up?
> > 
> > No. The files in utils are compiled without -mrtd or -mregparm, because 
> > otherwise they are incompatible against your C library. So it is necessary 
> > to 
> > compile files in PUPA in per-target basis.
> > 
> > BTW, are you good at reading assembly code generated by GCC? For this kind 
> > of 
> > problem, it is inevitable to take a look at what GCC produced. I myself 
> > will 
> > try your code as soon as possible.
> 
> It's a gcc bug triggered by the combination of -mregparm=3 and nested
> functions. The problem is that it wants to put the address of test in
> %ecx but that register is also used for the third argument with
> -mregparm=3. Below is a copy of the assembly code generated by gcc.

How should this be fixed for PUPA?  I assume not supporting some gcc
versions is no option. ;)

I see two options:

- Not using -mregparm=3 anymore.  This can be made dependent on the
  gcc version with autoconf I assume.

- When using nested functions with more than 3 parameters an attribute
  should be used for this function to disable regparm.  This can also
  be dependent on the gcc version.

To me the second option seems the best.  Does anyone see other options
or does someone have an preference?  If not I'll use option 2.

Thanks,
Marco