Re: New GCC, new option required?

[Kaul <mykaul () gmail com>]

- I've also tried to provide fixes for some (until I got both tired and
unable to fix those that result from the ASN.1 definitions) in
https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=5858.
- CLANG static analyzer was also quite helpful in finding issues. It just
takes hours to compile wireshark with it.
- First time I've heard of ptvcursors. Nice.

Y.


On Thu, Jul 14, 2011 at 5:51 AM, Bill Meier <wmeier () newsguy com> wrote:

> On 7/13/2011 7:38 PM, Guy Harris wrote:
>
> > Haven't you (and maybe others) been fixing the same issues already,
> > as  a result of Coverity warnings about the same thing?
> >
> > And how many of those are
> >
> > static void
> > dissect_whatever(...)
> > {
> >
> >                ...
> >
> >        proto_tree_add_item(tree, hf_foo, tvb, offset, len_foo, encoding);
> >        offset += len_foo;
> >        proto_tree_add_item(tree, hf_bar, tvb, offset, len_bar, encoding);
> >        offset += len_bar;
> > }
> >
> > and how many of those ultimately represent dissectors that should be
> > converted to use ptvcursors, in which case the "offset +=" stuff will
> > disappear into the ptvcursor code and not get whined about by dataflow
> > analyzers?
>
> I'd have to go back and look but I guess that some of the "Coverity
> [unused]" defects for the dissectors were related to the pattern as shown
> above:
> {
>    ...
>    offset += ...;
> }
>
>
>
> However, ISTR that many more were related to the following pattern:
> {
>        ...
>        foo = proto_tree_add_item(...);
>        offset += ...;
>        foo = proto_tree_add_item(...);
>        ...
> }
>
> Others were real bugs (such doing 'foo=proto_item_add_subtree()' and then
> failing to use the returned value in following 'proto_tree_add_item()'
> calls.
>
> At some point I stopped fixing "Coverity [unused]" even though ISTR that
> were (at least a few) more "unused" defects yet to be fixed.
>
> Some time later I started working on the GCC 4.6 "set-but-unused" warnings.
>
> I now see (after doing a little research) that it appears that the "unused"
> defects found by Coverity were only a subset of the "unused-but-set" cases
> found by GCC 4.6.
>
> I don't know what the pattern is for things not found by Coverity but I do
> note that many cases like the following weren't found by Coverity:
>
> {
>    ...
>    int foo;
>    ...
>    foo = ...;
>    ...
> }
>
>
> In any case: Since much of the "Coverity [unused"" dissector cases have
> already been fixed, much of the remaining (non-generated) dissector
> "set-but-not-used" cases seem to be for stuff not found by "Coverity
> [unused]".
>
> (See SVN #37716 for many examples of this type of fix).
>
>
>
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