On 5/2/2021 8:41 AM, Dave Nadler wrote:
> On 4/17/2021 10:34 AM, Dave Nadler wrote:
>> On 4/16/2021 3:24 PM, Dave Nadler wrote:
>>> Perhaps someone here can help...
>>>
>>> I'm doing a presentation on techniques for embedded, especially removing and 
>>> keeping out bugs ;-) Using an example project from last year. A reviewer of 
>>> my first draft suggested many of the bugs surfaced in the project would have 
>>> been caught by static analysis - but I haven't had such great luck in the past.
>>>
>>> Tried CPPcheck, and while it found some less-than-optimal stuff it only 
>>> found one of the real bugs discussed.
>>>
>>> Tried to get an evaluation copy of Coverity, but got a wildly annoying and 
>>> clueless sales person who promises a member of the right team will contact 
>>> me shortly (Real Soon Now).
>>>
>>> Bugs I had to fix and amenable to static analysis included:
>>> - uninitialized variable (only one found by CPPcheck)
>>> - use of magic 0xff index value as subscript off end of array
>>> - C macro with unguarded arguments getting wrong answer
>>> - use of int8 to index 1kb buffer (so only 256 bytes got used)
>>>
>>> Anybody able to recommend a tool they've used successfully?
>>> Thanks in advance,
>>> Best Regards, Dave
>>
>> Thanks all for the comments. I should have explained this project came from 
>> elsewhere; landed in my lap to add a minor feature which resulted in needing 
>> to do lots of debug of existing problems. I even rewrote part of it in C++ 
>> ;-)  Project is proprietary so Coverity scan is not applicable as that's only 
>> for FOSS. Only 5 (maybe 6?) of the top dozen bugs COULD be found by static 
>> analysis but certainly that would have been helpful.
>>
>> If anybody has an hour and would be interested to review the presentation 
>> first draft video PM me - I can always use some constructive comments and 
>> suggestions!
>>
>> Thanks again,
>> Best Regards, Dave
> 
> Further follow-up: Never heard back from Coverity (as expected).
> Tried Perforce Klocworks and got a very perky and slightly less annoying sales 
> person who promised prompt follow-up, and as usual none was forthcoming.
> 
> Any other static analysis tools you folks can suggest?

You're not going to find anything of the same caliber as Klocwork/Coverity
in the "discount/FOSS" aisle.

But, as I said, elsewhere, with enough (machine) "eyes" looking at your code,
you may eke out some insights that would evade a normal review.

Look at PVS Studio.  ConQAT won't necessarily give you the sorts of flags
that you're likely expecting from a static analysis tool; but, can help with
things like clone detection (more "smells" than actual "problems")

[Of course, there are other tools that do similar things]

On 4/17/2021 10:34 AM, Dave Nadler wrote:
> On 4/16/2021 3:24 PM, Dave Nadler wrote:
>> Perhaps someone here can help...
>>
>> I'm doing a presentation on techniques for embedded, especially 
>> removing and keeping out bugs ;-) Using an example project from last 
>> year. A reviewer of my first draft suggested many of the bugs surfaced 
>> in the project would have been caught by static analysis - but I 
>> haven't had such great luck in the past.
>>
>> Tried CPPcheck, and while it found some less-than-optimal stuff it 
>> only found one of the real bugs discussed.
>>
>> Tried to get an evaluation copy of Coverity, but got a wildly annoying 
>> and clueless sales person who promises a member of the right team will 
>> contact me shortly (Real Soon Now).
>>
>> Bugs I had to fix and amenable to static analysis included:
>> - uninitialized variable (only one found by CPPcheck)
>> - use of magic 0xff index value as subscript off end of array
>> - C macro with unguarded arguments getting wrong answer
>> - use of int8 to index 1kb buffer (so only 256 bytes got used)
>>
>> Anybody able to recommend a tool they've used successfully?
>> Thanks in advance,
>> Best Regards, Dave
> 
> Thanks all for the comments. I should have explained this project came 
> from elsewhere; landed in my lap to add a minor feature which resulted 
> in needing to do lots of debug of existing problems. I even rewrote part 
> of it in C++ ;-)&nbsp; Project is proprietary so Coverity scan is not 
> applicable as that's only for FOSS. Only 5 (maybe 6?) of the top dozen 
> bugs COULD be found by static analysis but certainly that would have 
> been helpful.
> 
> If anybody has an hour and would be interested to review the 
> presentation first draft video PM me - I can always use some 
> constructive comments and suggestions!
> 
> Thanks again,
> Best Regards, Dave

Further follow-up: Never heard back from Coverity (as expected).
Tried Perforce Klocworks and got a very perky and slightly less annoying 
sales person who promised prompt follow-up, and as usual none was 
forthcoming.

Any other static analysis tools you folks can suggest?

On 4/16/2021 3:24 PM, Dave Nadler wrote:
> Perhaps someone here can help...
> 
> I'm doing a presentation on techniques for embedded, especially removing 
> and keeping out bugs ;-) Using an example project from last year. A 
> reviewer of my first draft suggested many of the bugs surfaced in the 
> project would have been caught by static analysis - but I haven't had 
> such great luck in the past.
> 
> Tried CPPcheck, and while it found some less-than-optimal stuff it only 
> found one of the real bugs discussed.
> 
> Tried to get an evaluation copy of Coverity, but got a wildly annoying 
> and clueless sales person who promises a member of the right team will 
> contact me shortly (Real Soon Now).
> 
> Bugs I had to fix and amenable to static analysis included:
> - uninitialized variable (only one found by CPPcheck)
> - use of magic 0xff index value as subscript off end of array
> - C macro with unguarded arguments getting wrong answer
> - use of int8 to index 1kb buffer (so only 256 bytes got used)
> 
> Anybody able to recommend a tool they've used successfully?
> Thanks in advance,
> Best Regards, Dave

Thanks all for the comments. I should have explained this project came 
from elsewhere; landed in my lap to add a minor feature which resulted 
in needing to do lots of debug of existing problems. I even rewrote part 
of it in C++ ;-)  Project is proprietary so Coverity scan is not 
applicable as that's only for FOSS. Only 5 (maybe 6?) of the top dozen 
bugs COULD be found by static analysis but certainly that would have 
been helpful.

If anybody has an hour and would be interested to review the 
presentation first draft video PM me - I can always use some 
constructive comments and suggestions!

Thanks again,
Best Regards, Dave

On 16/04/2021 21:24, Dave Nadler wrote:
> Perhaps someone here can help...
> 
> I'm doing a presentation on techniques for embedded, especially removing
> and keeping out bugs ;-) Using an example project from last year. A
> reviewer of my first draft suggested many of the bugs surfaced in the
> project would have been caught by static analysis - but I haven't had
> such great luck in the past.
> 
> Tried CPPcheck, and while it found some less-than-optimal stuff it only
> found one of the real bugs discussed.
> 
> Tried to get an evaluation copy of Coverity, but got a wildly annoying
> and clueless sales person who promises a member of the right team will
> contact me shortly (Real Soon Now).
> 
> Bugs I had to fix and amenable to static analysis included:
> - uninitialized variable (only one found by CPPcheck)
> - use of magic 0xff index value as subscript off end of array
> - C macro with unguarded arguments getting wrong answer
> - use of int8 to index 1kb buffer (so only 256 bytes got used)
> 
> Anybody able to recommend a tool they've used successfully?
> Thanks in advance,
> Best Regards, Dave

Your first step should always be the compiler - a good compiler, with
optimisation enabled (that's essential) and lots of warnings will pick
up many such things.  It won't do everything, but it is certainly a good
start.  gcc in particular has got better and better at this over time -
I have found bugs in code (other people's code, of course :-) ) after
switching to a newer gcc and enabling more warnings.

Actually, that is perhaps the /second/ step.  The first step is to adopt
good coding practices (and perhaps a formal standard) that make it
easier to avoid writing the bugs in the first place, and to spot them
when they are made accidentally.  For example, a strong emphasis on
static inline functions rather than macros means your risk of macro
problems drops dramatically - and a coding standard that insists on
always guarding the arguments means you don't get the macro bug you
mentioned above.

On 16/04/2021 20:24, Dave Nadler wrote:
> Perhaps someone here can help...
> 
> I'm doing a presentation on techniques for embedded, especially removing 
> and keeping out bugs ;-) Using an example project from last year. A 
> reviewer of my first draft suggested many of the bugs surfaced in the 
> project would have been caught by static analysis - but I haven't had 
> such great luck in the past.
> 
> Tried CPPcheck, and while it found some less-than-optimal stuff it only 
> found one of the real bugs discussed.
> 
> Tried to get an evaluation copy of Coverity, but got a wildly annoying 
> and clueless sales person who promises a member of the right team will 
> contact me shortly (Real Soon Now).
> 
> Bugs I had to fix and amenable to static analysis included:
> - uninitialized variable (only one found by CPPcheck)
> - use of magic 0xff index value as subscript off end of array
> - C macro with unguarded arguments getting wrong answer
> - use of int8 to index 1kb buffer (so only 256 bytes got used)
> 
> Anybody able to recommend a tool they've used successfully?
> Thanks in advance,
> Best Regards, Dave

I uses PC_Lint Version 9, not the latest, but Gimple now only sell site 
licenses at rather high cost if you only need 1. It's still a cheapish 
solution.
Ristan Case it nice but has not been updated for years and is not likely 
to be.
Lint + MISRA is a bit like doing a code review with a colleague who 
objects to pretty much everything you do. For me its main virtue is in 
forcing you to think about stuff a little more.
On the current project (where I'm using these tools) it has certainly 
caught a few bugs but a lot more instances of stuff that can (and 
should) be expressed more clearly or simply.
The problem with working in a "MISRA compliant" environment is that 
slavish obedience is required which is often daft. The documentation 
burden of dealing with exceptions can become large.

On balance I think it improves my code. (And since on the current 
project no code reviews ever happen - it's all I've got :-(

All the above applies to C only.

MK

Am 16.04.2021 um 21:24 schrieb Dave Nadler:
> Tried CPPcheck, and while it found some less-than-optimal stuff it only
> found one of the real bugs discussed.
> 
> Tried to get an evaluation copy of Coverity, but got a wildly annoying
> and clueless sales person who promises a member of the right team will
> contact me shortly (Real Soon Now).
> 
> Bugs I had to fix and amenable to static analysis included:
> - uninitialized variable (only one found by CPPcheck)
> - use of magic 0xff index value as subscript off end of array
> - C macro with unguarded arguments getting wrong answer
> - use of int8 to index 1kb buffer (so only 256 bytes got used)
> 
> Anybody able to recommend a tool they've used successfully?

First and foremost: if you've been sloppy for decades, throwing ANY tool
at the existing codebase will bury you in "findings" and therefore not
be useful. So, you WILL have to dumb down the tool to make it usable. If
you're giving out big money for the tool, it'll be hard to predict
whether you'll end up using 90% or 10% of it.

That aside, I consider the free tools good enough. The bang-for-the-buck
ratio is hard to beat:

Recent gcc and clang versions learned to detect a lot of things that
previously only specialized tools would find (e.g. switch/case
fallthrough). Just turn on the bulk for a first test (-O2 -Wall
-Wextra), and turn on even more stuff later. For example, we're using
-Wconversion which can be really annoying but has found/would have found
a few real bugs in our codebase. Of course this will bury you in
warnings if you haven't tried it before.

cppcheck has the advantage of knowing some APIs, i.e. it will find some
file descriptor leaks. On the downside, it has some annoying false
positives (e.g. in C++11, it will flag every other method of a local
class if one method is using std::move on a member).

Now I've also used Klocwork (which would be the same league as
Coverity), but consider its gain minimal. In our codebase, it produces
lots of false positives, some of which lead to sore forehead due to
excessive facepalming. One annoying example is its attempt to implement
the MISRA pseudo-type system, where '1 << 10' is an error because '1'
has type uint8_t for MISRA. Problem is, it considers 'UINT32_C(1)' to
have type uint8_t as well. Another annoying example is that whenever I
call a class method 'open', it expects a call to 'close' somewhere or
flags a resource leak. And sometimes it gets lost inside STL and tells
me that standard class has a leak; at least you won't have that problem
when checking only C :) On the plus side, it has a database to silence
one finding for the future.


  Stefan

Dave Nadler <drn@nadler.com> writes:
> Anybody able to recommend a tool they've used successfully?

I haven't personally used it, but Frama-C is well regarded for this.

This isn't specifically about static analysis, but you might find
it interesting:

   https://dwheeler.com/essays/high-assurance-floss.html

Also, Dawson Engler's site http://web.stanford.edu/~engler has lots of
stuff about static analysis (he is the founder or a co-founder of
Coverity).

Finally, ask yourself why you are still using C in this day and age at
all, if correctness is critical.  Ada, Rust, or even C++ can keep you
out of a lot of trouble.

On 4/16/2021 1:54 PM, Gerhard Hoffmann wrote:
> Am 16.04.21 um 21:56 schrieb Don Y:
> 
>>> Anybody able to recommend a tool they've used successfully?
>>
>> Coverity will require deep pockets/"high visibility" (they're out
>> to make money).
> 
> Friends of mine were quite happy with it verifying our 10 M lines
> of code wafertester control software.

Oh, it's a wonderful tool!  But, for most small organizations,
it's likely seen as an "unnecessary expense".

> IIRC it is free to use on open source software.

They have a cloud-based service that will analyze your codebase.
I'm not sure how willing most firms will be to upload the "family
jewels"...

If you're an *established* open-source project, you'll get
more attention (hence NetBSD).  But, you'll still play on their
terms.

On 4/16/2021 1:47 PM, Don Y wrote:

> I suspect it may be "beyond your charter" but an interesting
> exercise might be to show an "initial implementation", note
> the number of faults found (manually or with tools) in contrast
> with a refactored implementation (though refactored BEFORE the
> analysis was done).  The point being to show how coding styles
> (designs?) can impact the quality of the code.
> 
> "Here's a huge piece of spaghetti code.  Note the number of
> errors...  Now, the same (functionally) code written in a
> better style..."

You can also suggest mechanizing testing -- and the consequences it
has on how you structure the code so that it can be tested in that
way.  This is particularly helpful in embedded design where it's
too easy to write code that *requires* hardware to run properly
(yet, chances are, many of the algorithms could be tested without
that hardware if the hardware dependencies were isolated).

I write most of my OSs and drivers so that I can run them in an
interpreter or simulator.  Catch the obvious bugs where it's easy
to do so (running at DC).