X server failing on PowerPC

X server failing on PowerPC

[Gary Thomas]

When built from a recent OE-core using GCC 4.7.x, the X server
fails on PowerPC targets.  Filed as Poky/Yocto bug #2460, it boils down
to a sequence of code like this:

    void *ptr;
    switch(XX) {
       case a:
          define_some_structure A;
          ptr = &A;
          break;
       case b:
          define_some_structure B;
          ptr = &B;
          break;
    }
    call_some_function(ptr);

I didn't explore how this messes up, just that it does when compiled
on PowerPC with GCC 4.7.x.  Note that it works fine on ARM (and I assume
x86 as well)

Is this even legal C?  even if it works [has worked] for 20+ years?

Should I propose my patch? I'm only interested in xserver-kdrive_1.7.99.2,
but I think this probably affects all X server instances.

-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------

Re: X server failing on PowerPC

[Phil Blundell]

On Wed, 2012-05-16 at 05:50 -0600, Gary Thomas wrote:
>     void *ptr;
>     switch(XX) {
>        case a:
>           define_some_structure A;
>           ptr = &A;
>           break;
>        case b:
>           define_some_structure B;
>           ptr = &B;
>           break;
>     }
>     call_some_function(ptr);
> 
>[...]
>
> Is this even legal C?  

No. 

p.