[coreboot] unexpected exception errors loading vga rom

[Stefan Reinauer]

On 22.04.2009 23:26 Uhr, Peter Stuge wrote:
> Joseph Smith wrote:
>   
>> Wow looks like there are alot of bugs in romcc.c !
>>     
>
> I only looked at the very first ones:
>
> API  Argument with 'nonnull' attribute passed null  romcc.c:10780
>
> The thing to note here is that there are conditions to the error.
> Code can very well be making sure that those conditions are in fact
> never met, and I don't think scanbuild does a complex enough analysis
> to know for sure. (Quite understandably!)
>
> I agree it would be nice to have perfect analysis, and/or code more
> suitable for analysis, but just want to point out that there can be
> false positives depending on the coding style.
>   

Absolutely agreed. Not all findings by scan-build make sense (for us).
There are cases where it will find an access to memory which is not
backed by a C variable to be undefined.
(something like *(u8 *)0xdeadbeef) ... Makes a lot of sense in (most)
user space applications, but we need to be careful. I tried to fix a
couple of findings, even if they were not strictly required (such as
attribute((noreturn)) in a userspace function calling exit() ... the
attribute is not inherited in scan-build as they don't do
interprocedural checks yet) to improve the overall results.

There are far better ways of doing static code analysis, most of them
involve a lot of time and money. That said, if someone with a PolySpace
license (Carl-Daniel?) and a few couple of days of time reads this,
please help us verify our code! Same for QA-C et al.

Stefan


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