Re: New GCC, new option required?

[Bill Meier <wmeier () newsguy com>]

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).


___________________________________________________________________________
Sent via:    Wireshark-dev mailing list <wireshark-dev () wireshark org>
Archives:    http://www.wireshark.org/lists/wireshark-dev
Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev
            mailto:wireshark-dev-request () wireshark org?subject=unsubscribe