Re: [PATCH] Redudant initilization

Ranier Vilela <ranier.vf@gmail.com>

From: Ranier Vilela <ranier.vf@gmail.com>

To: Tom Lane <tgl@sss.pgh.pa.us>

Cc: Bruce Momjian <bruce@momjian.us>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>

Date: 2020-09-05T16:40:37Z

Lists: pgsql-hackers

Attachments

fix_redudant_initialization_firstmissingnum_heaptuple.patch (application/octet-stream) patch
fix_redudant_initialization_offsetnumber_gistutil.patch (application/octet-stream) patch
fix_redudant_initialization_formatting.patch (application/octet-stream) patch
fix_redudant_initialization_arrayfuncs.patch (application/octet-stream) patch
fix_redudant_initialization_bklno_hash.patch (application/octet-stream) patch
fix_redudant_initialization_parse_utilcmd.patch (application/octet-stream) patch
fix_redudant_initialization_procarray.patch (application/octet-stream) patch
fix_redudant_initialization_status_nbtsearch.patch (application/octet-stream) patch
fix_redudant_initialization_storage.patch (application/octet-stream) patch
fix_redudant_initialization_spell.patch (application/octet-stream) patch
fix_redudant_initialization_syslogger.patch (application/octet-stream) patch
fix_redudant_initialization_to_tsany.patch (application/octet-stream) patch
fix_redudant_initialization_tsrank.patch (application/octet-stream) patch
fix_redudant_initialization_tuplesort.patch (application/octet-stream) patch
fix_redudant_initialization_wparser_def.patch (application/octet-stream) patch
fix_redudant_prefix_spgtextproc.patch (application/octet-stream) patch
fix_redudant_waits_xlog.patch (application/octet-stream) patch

Em sex., 4 de set. de 2020 às 18:20, Ranier Vilela <ranier.vf@gmail.com>
escreveu:

> Em sex., 4 de set. de 2020 às 14:40, Tom Lane <tgl@sss.pgh.pa.us>
> escreveu:
>
>> Bruce Momjian <bruce@momjian.us> writes:
>> > I have to say, I am kind of stumped why compilers do not warn of such
>> > cases, and why we haven't gotten reports about these cases before.
>>
>> I was just experimenting with clang's "scan-build" tool.  It finds
>> all of the cases you just fixed, and several dozen more beside.
>> Quite a few are things that, as a matter of style, we should *not*
>> change, for instance
>>
>> rewriteHandler.c:2807:5: warning: Value stored to 'outer_reloids' is
>> never read
>>                                 outer_reloids =
>> list_delete_last(outer_reloids);
>>                                 ^
>>  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
> There are some like this, in the analyzes that I did.
> Even when it is the last action of the function.
>
>
>> Failing to update the list pointer here would just be asking for bugs.
>> However, I see some that look like genuine oversights; will go fix.
>>
> Thanks for fixing this.
>
>
>> (I'm not sure how much I trust scan-build overall.  It produces a
>> whole bunch of complaints about null pointer dereferences, for instance.
>> If those aren't 99% false positives, we'd be crashing constantly.
>> It's also dog-slow.  But it might be something to try occasionally.)
>>
> I believe it would be very beneficial.
>
> Attached is a patch I made in March/2020, but due to problems,
> it was sent but did not make the list.
> Would you mind taking a look?
> Certainly, if accepted, rebasing would have to be done.
>
Here it is simplified, splitted and rebased.
Some are bogus, others are interesting.

regards,
Ranier Vilela

Commits

Yet more elimination of dead stores and useless initializations.
- a5cc4dab6d1d 14.0 landed
Remove still more useless assignments.
- 9a851039aac6 14.0 landed
Remove some more useless assignments.
- 38a2d703298c 14.0 landed