Re: [GSoC-2021] Interested in project `Extend the static analysis pass`

[David Malcolm <dmalcolm@redhat.com>]

On Thu, 2021-03-25 at 14:52 +0530, Saloni Garg via Gcc wrote:
> Hi all,
> I am an undergraduate student in AMU, Aligarh. I am interested in the
> project* `Extend the static analysis pass`. *I have followed this(
> https://gcc.gnu.org/pipermail/gcc/2021-March/234941.html) and been
> able to
> successfully build and successfully ran and pass the test suite for C
> and
> C++.
> 
> I found this sub-project `C++ support (new/delete checking,
> exceptions,
> etc)` interesting and may be the conservative code for this can be
> made
> along the lines of malloc/free implementation in C. I found here(
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94355) that some part of
> it
> has already been implemented . I would like to expand it further and
> learn
> about it, maybe start with writing some test cases, please let me
> know.
> 
> Further, I am inclined on this(
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97111). Let me know if
> it is
> still available.
> 
> Looking forward to hearing from you guys.
> Thanks,
> Saloni Garg

Hi!

I'm the author/maintainer of the static analysis pass, and would be the
mentor for any GSoC project(s) involving it.

I've already implemented most of the new/delete checking in GCC 11; the
big missing component there is exception-handling.

Implementing exception-handling in the analyzer could make a good GSoC
project: it's non-trivial, but hopefully doable in one summer.  I see
you've already seen bug 97111, and there are some links in that bug to
resources.  Given that the analyzer runs on the gimple-ssa
representation, by the time it sees the code, much of the exception-
handling has already been translated into calls to various __cxa_-
prefixed functions in the C++ runtime, so part of the work would
involve "teaching" the analyzer about those functions.  One way to make
a start on this would be to create a collection of trivial C++ examples
that use exceptions, and then look at analyzer dumps to see what IR is
being "seen" by the analyzer for the various constructs.   (I actually
started this a long time ago and have a very crude barely-working
prototype, but it was just the start, and I've forgotten almost all of
it...)

Hope this is helpful
Dave