Re: Compiler warnings

On Tue, Dec 6, 2016 at 3:23 PM, Stephen Frost <sfrost@snowman.net> wrote:
> * Stephen Frost (sfrost@snowman.net) wrote:
>> Not sure if anyone else has been seeing these, but I'm getting a bit
>> tired of them.  Neither is a live bug, but they also seem pretty simple
>> to fix.  The attached patch makes both of these warnings go away.  At
>> least for my common build, these are the only warnings that are thrown.
>>
>> I'm building with:
>>
>> gcc (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
>>
>> .../src/backend/storage/lmgr/lwlock.c: In function ‘LWLockRelease’:
>> .../src/backend/storage/lmgr/lwlock.c:1802:5: warning: ‘mode’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
>>   if (mode == LW_EXCLUSIVE)
>>      ^
>> .../src/backend/utils/cache/plancache.c: In function ‘GetCachedPlan’:
>> .../src/backend/utils/cache/plancache.c:1232:9: warning: ‘plan’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
>>   return plan;
>>          ^
>
> Given the lack of screaming, I'll push the attached in a bit, which just
> initializes the two variables being complained about.  As mentioned,
> there doesn't appear to be any live bugs here, this is just to silence
> the compiler warnings.

In LWLockRelease, why not just move mode = held_lwlocks[i].mode; after
the if (i < 0) elog(...), instead of initializing with a bogus value?

--
Robert Haas
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