[coreboot] printk and side effects

Stefan Reinauer stefan.reinauer at coresystems.de
Sat Apr 17 20:25:05 CEST 2010

On 17.04.2010, at 16:41, Myles Watson <mylesgw at gmail.com> wrote:

> This is a reminder to myself in case it is obvious to everyone else:
> It seems very difficult to guarantee that the removal/insertion of a  
> print statement has no other effects.

Thanks for sharing this kind of information. This is definitely not  
obvious and people need to be aware of it.

I have seen similar side effects with printk too which lead to our  
current printk which evaluates the varargs, even if the maximum log  
level is below the printk's ...

> I printed out the location of a variable, and that changed where it  
> was stored (from a register to being placed on the stack)...
> This might not be a traditional "side effect", but it changed the  
> behavior of the code and surprised me.

In which way was the behavior changed? Anything we can watch out for?


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