Date: Tue, 6 Dec 2016 15:23:05 -0500
From: Stephen Frost <sfrost@snowman.net>
To: pgsql-hackers@postgresql.org
Subject: Re: Compiler warnings
Message-ID: <20161206202305.GQ23417@tamriel.snowman.net>
References: <20161129152102.GR13284@tamriel.snowman.net>
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All,

* 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.
>=20
> I'm building with:
>=20
> gcc (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
>=20
> .../src/backend/storage/lmgr/lwlock.c: In function =E2=80=98LWLockRelease=
=E2=80=99:
> .../src/backend/storage/lmgr/lwlock.c:1802:5: warning: =E2=80=98mode=E2=
=80=99 may be used uninitialized in this function [-Wmaybe-uninitialized]
>   if (mode =3D=3D LW_EXCLUSIVE)
>      ^
> .../src/backend/utils/cache/plancache.c: In function =E2=80=98GetCachedPl=
an=E2=80=99:
> .../src/backend/utils/cache/plancache.c:1232:9: warning: =E2=80=98plan=E2=
=80=99 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.

Thanks!

Stephen

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=46rom afe53a0fa8a53c080b77a7334531ff3a5dc976d4 Mon Sep 17 00:00:00 2001
=46rom: Stephen Frost <sfrost@snowman.net>
Date: Tue, 6 Dec 2016 15:19:09 -0500
Subject: [PATCH] Silence compiler warnings

Initialize a couple of variables to silence compiler warnings.  There
aren't any cases where these variables could actually end up being used
while uninitialized, but at least gcc 5.4.0-6ubuntu1~16.04.4 doesn't
quite have the smarts to realize that.

Discussion: https://www.postgresql.org/message-id/20161129152102.GR13284%40=
tamriel.snowman.net
---
 src/backend/storage/lmgr/lwlock.c   | 2 +-
 src/backend/utils/cache/plancache.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/l=
wlock.c
index 9c6862f..909ff45 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -1770,7 +1770,7 @@ LWLockUpdateVar(LWLock *lock, uint64 *valptr, uint64 =
val)
 void
 LWLockRelease(LWLock *lock)
 {
-	LWLockMode	mode;
+	LWLockMode	mode =3D LW_EXCLUSIVE;
 	uint32		oldstate;
 	bool		check_waiters;
 	int			i;
diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/=
plancache.c
index 884cdab..a37074b 100644
--- a/src/backend/utils/cache/plancache.c
+++ b/src/backend/utils/cache/plancache.c
@@ -1128,7 +1128,7 @@ CachedPlan *
 GetCachedPlan(CachedPlanSource *plansource, ParamListInfo boundParams,
 			  bool useResOwner)
 {
-	CachedPlan *plan;
+	CachedPlan *plan =3D NULL;
 	List	   *qlist;
 	bool		customplan;
=20
--=20
2.7.4


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