Suppress compiler warnings from commit ee895a6.

tglsfdc · tglsfdc · commit 7292fd8f1c78 · 2021-01-26T13:58:18.000-05:00
For obscure reasons, some buildfarm members are now generating complaints about plpgsql_call_handler's "retval" variable possibly being used uninitialized. It seems no less safe than it was before that commit, but these complaints are (mostly?) new. I trust that initializing the variable where it's declared will be enough to shut that up. I also notice that some compilers are warning about setjmp clobber of the same variable, which is maybe a bit more defensible. Mark it volatile to silence that. Also, rearrange the logic to give procedure_resowner a single point of initialization, in hopes of silencing some setjmp-clobber warnings about that. (Marking it volatile would serve too, but its sibling variables are depending on single assignment, so let's stick with that method.) Discussion: https://postgr.es/m/E1l4F1z-0000cN-Lx@gemulon.postgresql.org
diff --git a/src/pl/plpgsql/src/pl_handler.c b/src/pl/plpgsql/src/pl_handler.c
@@ -224,8 +224,8 @@ plpgsql_call_handler(PG_FUNCTION_ARGS)
 	bool		nonatomic;
 	PLpgSQL_function *func;
 	PLpgSQL_execstate *save_cur_estate;
-	ResourceOwner procedure_resowner = NULL;
-	Datum		retval;
+	ResourceOwner procedure_resowner;
+	volatile Datum retval = (Datum) 0;
 	int			rc;
 
 	nonatomic = fcinfo->context &&
@@ -254,9 +254,9 @@ plpgsql_call_handler(PG_FUNCTION_ARGS)
 	 * Therefore, be very wary of adding any code between here and the PG_TRY
 	 * block.
 	 */
-	if (nonatomic && func->requires_procedure_resowner)
-		procedure_resowner =
-			ResourceOwnerCreate(NULL, "PL/pgSQL procedure resources");
+	procedure_resowner =
+		(nonatomic && func->requires_procedure_resowner) ?
+		ResourceOwnerCreate(NULL, "PL/pgSQL procedure resources") : NULL;
 
 	PG_TRY();
 	{
@@ -271,7 +271,7 @@ plpgsql_call_handler(PG_FUNCTION_ARGS)
 		{
 			plpgsql_exec_event_trigger(func,
 									   (EventTriggerData *) fcinfo->context);
-			retval = (Datum) 0;
+			/* there's no return value in this case */
 		}
 		else
 			retval = plpgsql_exec_function(func, fcinfo,
