Re: [arm-gnu] Compiling Safety Related Systems?

[Charles Manning <manningc2@xxxxxxxxxxxxx>]

Hi Mark

Thanks for the clarification.

On Wednesday 10 February 2010 12:57:56 Mark Mitchell wrote:
> Charles Manning wrote:
> >> - error/defect information (for a certain build)
> >
> > Perhaps the only real concern.

What I really meant here was that there are so many versions, from so many 
sources, that qualification becomes a headache unless you get the compiler 
from people such as CS who ship you a nailed-down binary that has been 
rigorously tested by people with the motivation and resources to do the 
testing.

For example I've sometimes pulled binaries from various places and sometimes 
built from source and always ended up with something that seems to work fine, 
but that has always been just a step of faith with no qualification. If you 
build a few hundred k lines into a GPS firmware and it boots, tracks 
satellites, spits out correct positions and passes all product QA tests then 
you can be forgiven for saying "it works!"

I know qualification is important in some fields but in reality compiler bugs 
break far fewer products than application/algorithmic bugs.

>
> Every CodeSourcery build (Lite Edition and our commercial products) goes
> through a test process that involves hundreds of thousands, or,
> depending on the configuration, millions of tests.  Our engineers
> examine these results, and investigate causes of failure (which are
> often things like insufficient memory on a target system, or a Linux
> kernel with a defect).  The results are logged with each build that we
> ship so that we can later reexamine test results from a previous build.
>
> Interpreting the test results is not easy, and some of the tests are
> proprietary (to us and/or to third parties), so we do not post this
> information.  But, we do have it and can provide customers with
> information about our processes.
>
> Our compilers certainly do have bugs (as do all versions of GCC, and, I
> expect, all versions of all C/C++ compilers).  However, we work with our
> customers to resolve critical defects as quickly as possible.
>
> As one reference point, I'll mention that Wind River's VxWorks operating
> system, which is routinely used in safety-critical applications, ships
> with versions of GCC built and supported by CodeSourcery.  (These are
> not the same binaries that we provide as commercial products, but they
> are built using substantially similar processes.)

That is indeed good to know and that's clearly a big added value.

-- Charles