Clean up compiler warnings from unused variables with asserts disabled

For those variables only used when asserts are enabled, use a new
macro PG_USED_FOR_ASSERTS_ONLY, which expands to
__attribute__((unused)) when asserts are not enabled.

src/backend/access/hash/hashovfl.c

@@ -391,7 +391,7 @@ _hash_freeovflpage(Relation rel, Buffer ovflbuf,
 	uint32		ovflbitno;
 	int32		bitmappage,
 				bitmapbit;
-	Bucket		bucket;
+	Bucket		bucket PG_USED_FOR_ASSERTS_ONLY;
 
 	/* Get information from the doomed page */
 	_hash_checkpage(rel, ovflbuf, LH_OVERFLOW_PAGE);

src/backend/executor/execCurrent.c

@@ -151,7 +151,7 @@ execCurrentOf(CurrentOfExpr *cexpr,
 	{
 		ScanState  *scanstate;
 		bool		lisnull;
-		Oid			tuple_tableoid;
+		Oid			tuple_tableoid PG_USED_FOR_ASSERTS_ONLY;
 		ItemPointer tuple_tid;
 
 		/*

src/backend/executor/nodeMaterial.c

@@ -66,7 +66,7 @@ ExecMaterial(MaterialState *node)
 			 * Allocate a second read pointer to serve as the mark. We know it
 			 * must have index 1, so needn't store that.
 			 */
-			int			ptrno;
+			int			ptrno PG_USED_FOR_ASSERTS_ONLY;
 
 			ptrno = tuplestore_alloc_read_pointer(tuplestorestate,
 												  node->eflags);

src/backend/executor/nodeSetOp.c

@@ -344,7 +344,7 @@ setop_fill_hash_table(SetOpState *setopstate)
 	SetOp	   *node = (SetOp *) setopstate->ps.plan;
 	PlanState  *outerPlan;
 	int			firstFlag;
-	bool		in_first_rel;
+	bool		in_first_rel PG_USED_FOR_ASSERTS_ONLY;
 
 	/*
 	 * get state info from node

src/backend/executor/nodeWorktablescan.c

@@ -30,7 +30,6 @@ static TupleTableSlot *
 WorkTableScanNext(WorkTableScanState *node)
 {
 	TupleTableSlot *slot;
-	EState	   *estate;
 	Tuplestorestate *tuplestorestate;
 
 	/*
@@ -48,8 +47,7 @@ WorkTableScanNext(WorkTableScanState *node)
 	 * worktable.  Therefore, we don't need a private read pointer for the
 	 * tuplestore, nor do we need to tell tuplestore_gettupleslot to copy.
 	 */
-	estate = node->ss.ps.state;
-	Assert(ScanDirectionIsForward(estate->es_direction));
+	Assert(ScanDirectionIsForward(node->ss.ps.state->es_direction));
 
 	tuplestorestate = node->rustate->working_table;
 

src/backend/libpq/be-fsstubs.c

@@ -378,7 +378,7 @@ lo_import_internal(text *filename, Oid lobjOid)
 {
 	File		fd;
 	int			nbytes,
-				tmp;
+				tmp PG_USED_FOR_ASSERTS_ONLY;
 	char		buf[BUFSIZE];
 	char		fnamebuf[MAXPGPATH];
 	LargeObjectDesc *lobj;

src/backend/libpq/pqcomm.c

@@ -1373,7 +1373,7 @@ fail:
 void
 pq_putmessage_noblock(char msgtype, const char *s, size_t len)
 {
-	int			res;
+	int			res PG_USED_FOR_ASSERTS_ONLY;
 	int			required;
 
 	/*

src/backend/optimizer/path/costsize.c

@@ -3583,7 +3583,7 @@ void
 set_subquery_size_estimates(PlannerInfo *root, RelOptInfo *rel)
 {
 	PlannerInfo *subroot = rel->subroot;
-	RangeTblEntry *rte;
+	RangeTblEntry *rte PG_USED_FOR_ASSERTS_ONLY;
 	ListCell   *lc;
 
 	/* Should only be applied to base relations that are subqueries */

src/backend/parser/analyze.c

@@ -1588,7 +1588,7 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt,
 		/* Process leaf SELECT */
 		Query	   *selectQuery;
 		char		selectName[32];
-		RangeTblEntry *rte;
+		RangeTblEntry *rte PG_USED_FOR_ASSERTS_ONLY;
 		RangeTblRef *rtr;
 		ListCell   *tl;
 

src/backend/storage/file/fd.c

@@ -685,7 +685,7 @@ LruInsert(File file)
 		/* seek to the right position */
 		if (vfdP->seekPos != (off_t) 0)
 		{
-			off_t		returnValue;
+			off_t		returnValue PG_USED_FOR_ASSERTS_ONLY;
 
 			returnValue = lseek(vfdP->fd, vfdP->seekPos, SEEK_SET);
 			Assert(returnValue != (off_t) -1);

src/backend/storage/lmgr/predicate.c

@@ -2013,7 +2013,7 @@ RestoreScratchTarget(bool lockheld)
 static void
 RemoveTargetIfNoLongerUsed(PREDICATELOCKTARGET *target, uint32 targettaghash)
 {
-	PREDICATELOCKTARGET *rmtarget;
+	PREDICATELOCKTARGET *rmtarget PG_USED_FOR_ASSERTS_ONLY;
 
 	Assert(LWLockHeldByMe(SerializablePredicateLockListLock));
 
@@ -2074,7 +2074,7 @@ DeleteChildTargetLocks(const PREDICATELOCKTARGETTAG *newtargettag)
 		{
 			uint32		oldtargettaghash;
 			LWLockId	partitionLock;
-			PREDICATELOCK *rmpredlock;
+			PREDICATELOCK *rmpredlock PG_USED_FOR_ASSERTS_ONLY;
 
 			oldtargettaghash = PredicateLockTargetTagHashCode(&oldtargettag);
 			partitionLock = PredicateLockHashPartitionLock(oldtargettaghash);
@@ -2227,7 +2227,7 @@ DecrementParentLocks(const PREDICATELOCKTARGETTAG *targettag)
 	{
 		uint32		targettaghash;
 		LOCALPREDICATELOCK *parentlock,
-				   *rmlock;
+				   *rmlock PG_USED_FOR_ASSERTS_ONLY;
 
 		parenttag = nexttag;
 		targettaghash = PredicateLockTargetTagHashCode(&parenttag);

src/backend/storage/lmgr/proc.c

@@ -808,7 +808,7 @@ static void
 AuxiliaryProcKill(int code, Datum arg)
 {
 	int			proctype = DatumGetInt32(arg);
-	PGPROC	   *auxproc;
+	PGPROC	   *auxproc PG_USED_FOR_ASSERTS_ONLY;
 
 	Assert(proctype >= 0 && proctype < NUM_AUXILIARY_PROCS);
 

src/backend/utils/adt/selfuncs.c

@@ -3874,7 +3874,7 @@ convert_string_datum(Datum value, Oid typid)
 	{
 		char	   *xfrmstr;
 		size_t		xfrmlen;
-		size_t		xfrmlen2;
+		size_t		xfrmlen2 PG_USED_FOR_ASSERTS_ONLY;
 
 		/*
 		 * Note: originally we guessed at a suitable output buffer size, and
@@ -6408,7 +6408,7 @@ btcostestimate(PG_FUNCTION_ARGS)
 		RestrictInfo *rinfo = (RestrictInfo *) lfirst(lcc);
 		Expr	   *clause;
 		Node	   *leftop,
-				   *rightop;
+				   *rightop PG_USED_FOR_ASSERTS_ONLY;
 		Oid			clause_op;
 		int			op_strategy;
 		bool		is_null_op = false;

src/bin/psql/psqlscan.l

@@ -1474,7 +1474,7 @@ psql_scan_slash_option(PsqlScanState state,
 					   bool semicolon)
 {
 	PQExpBufferData mybuf;
-	int			lexresult;
+	int			lexresult PG_USED_FOR_ASSERTS_ONLY;
 	char		local_quote;
 
 	/* Must be scanning already */

src/include/c.h

@@ -710,6 +710,18 @@ typedef NameData *Name;
 #define STATUS_WAITING			(2)
 
 
+/*
+ * Append PG_USED_FOR_ASSERTS_ONLY to definitions of variables that are only
+ * used in assert-enabled builds, to avoid compiler warnings about unused
+ * variables in assert-disabled builds.
+ */
+#ifdef USE_ASSERT_CHECKING
+#define PG_USED_FOR_ASSERTS_ONLY
+#else
+#define PG_USED_FOR_ASSERTS_ONLY __attribute__((unused))
+#endif
+
+
 /* gettext domain name mangling */
 
 /*