Remove unnecessary array object_classes[] in dependency.c

object_classes[] provided unnecessary indirection between catalog OIDs
and the enum ObjectClass when calling add_object_address().  This array
has been originally introduced in 30ec31604d5 and was useful because not
all relation OIDs were compile-time constants back then, which has not
been the case for a long time now for all the elements of ObjectClass.

This commit removes object_classes[], switching to the catalog OIDs
when calling add_object_address().  This shaves some code while saving
in maintenance because it was necessary to maintain the enum ObjectClass
and the array in sync when adding new object types.

Reported-by: Jeff Davis
Author: Jelte Fennema-Nio
Reviewed-by: Jian He, Michael Paquier
Discussion: https://postgr.es/m/CAGECzQT3caUbcCcszNewCCmMbCuyP7XNAm60J3ybd6PN5kH2Dw@mail.gmail.com

2 files changed, 63 insertions, 122 deletions

diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index df9886efc95..2eb41d537bb 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -144,60 +144,6 @@ typedef struct
 	List	   *rtables;		/* list of rangetables to resolve Vars */
 } find_expr_references_context;
 
-/*
- * This constant table maps ObjectClasses to the corresponding catalog OIDs.
- * See also getObjectClass().
- */
-static const Oid object_classes[] = {
-	RelationRelationId,			/* OCLASS_CLASS */
-	ProcedureRelationId,		/* OCLASS_PROC */
-	TypeRelationId,				/* OCLASS_TYPE */
-	CastRelationId,				/* OCLASS_CAST */
-	CollationRelationId,		/* OCLASS_COLLATION */
-	ConstraintRelationId,		/* OCLASS_CONSTRAINT */
-	ConversionRelationId,		/* OCLASS_CONVERSION */
-	AttrDefaultRelationId,		/* OCLASS_DEFAULT */
-	LanguageRelationId,			/* OCLASS_LANGUAGE */
-	LargeObjectRelationId,		/* OCLASS_LARGEOBJECT */
-	OperatorRelationId,			/* OCLASS_OPERATOR */
-	OperatorClassRelationId,	/* OCLASS_OPCLASS */
-	OperatorFamilyRelationId,	/* OCLASS_OPFAMILY */
-	AccessMethodRelationId,		/* OCLASS_AM */
-	AccessMethodOperatorRelationId, /* OCLASS_AMOP */
-	AccessMethodProcedureRelationId,	/* OCLASS_AMPROC */
-	RewriteRelationId,			/* OCLASS_REWRITE */
-	TriggerRelationId,			/* OCLASS_TRIGGER */
-	NamespaceRelationId,		/* OCLASS_SCHEMA */
-	StatisticExtRelationId,		/* OCLASS_STATISTIC_EXT */
-	TSParserRelationId,			/* OCLASS_TSPARSER */
-	TSDictionaryRelationId,		/* OCLASS_TSDICT */
-	TSTemplateRelationId,		/* OCLASS_TSTEMPLATE */
-	TSConfigRelationId,			/* OCLASS_TSCONFIG */
-	AuthIdRelationId,			/* OCLASS_ROLE */
-	AuthMemRelationId,			/* OCLASS_ROLE_MEMBERSHIP */
-	DatabaseRelationId,			/* OCLASS_DATABASE */
-	TableSpaceRelationId,		/* OCLASS_TBLSPACE */
-	ForeignDataWrapperRelationId,	/* OCLASS_FDW */
-	ForeignServerRelationId,	/* OCLASS_FOREIGN_SERVER */
-	UserMappingRelationId,		/* OCLASS_USER_MAPPING */
-	DefaultAclRelationId,		/* OCLASS_DEFACL */
-	ExtensionRelationId,		/* OCLASS_EXTENSION */
-	EventTriggerRelationId,		/* OCLASS_EVENT_TRIGGER */
-	ParameterAclRelationId,		/* OCLASS_PARAMETER_ACL */
-	PolicyRelationId,			/* OCLASS_POLICY */
-	PublicationNamespaceRelationId, /* OCLASS_PUBLICATION_NAMESPACE */
-	PublicationRelationId,		/* OCLASS_PUBLICATION */
-	PublicationRelRelationId,	/* OCLASS_PUBLICATION_REL */
-	SubscriptionRelationId,		/* OCLASS_SUBSCRIPTION */
-	TransformRelationId			/* OCLASS_TRANSFORM */
-};
-
-/*
- * Make sure object_classes is kept up to date with the ObjectClass enum.
- */
-StaticAssertDecl(lengthof(object_classes) == LAST_OCLASS + 1,
-				 "object_classes[] must cover all ObjectClasses");
-
 
 static void findDependentObjects(const ObjectAddress *object,
 								 int objflags,
@@ -219,7 +165,7 @@ static void process_function_rte_ref(RangeTblEntry *rte, AttrNumber attnum,
 									 find_expr_references_context *context);
 static void eliminate_duplicate_dependencies(ObjectAddresses *addrs);
 static int	object_address_comparator(const void *a, const void *b);
-static void add_object_address(ObjectClass oclass, Oid objectId, int32 subId,
+static void add_object_address(Oid classId, Oid objectId, int32 subId,
 							   ObjectAddresses *addrs);
 static void add_exact_object_address_extra(const ObjectAddress *object,
 										   const ObjectAddressExtra *extra,
@@ -1786,7 +1732,7 @@ find_expr_references_walker(Node *node,
 		if (rte->rtekind == RTE_RELATION)
 		{
 			/* If it's a plain relation, reference this column */
-			add_object_address(OCLASS_CLASS, rte->relid, var->varattno,
+			add_object_address(RelationRelationId, rte->relid, var->varattno,
 							   context->addrs);
 		}
 		else if (rte->rtekind == RTE_FUNCTION)
@@ -1812,7 +1758,7 @@ find_expr_references_walker(Node *node,
 		Oid			objoid;
 
 		/* A constant must depend on the constant's datatype */
-		add_object_address(OCLASS_TYPE, con->consttype, 0,
+		add_object_address(TypeRelationId, con->consttype, 0,
 						   context->addrs);
 
 		/*
@@ -1823,7 +1769,7 @@ find_expr_references_walker(Node *node,
 		 */
 		if (OidIsValid(con->constcollid) &&
 			con->constcollid != DEFAULT_COLLATION_OID)
-			add_object_address(OCLASS_COLLATION, con->constcollid, 0,
+			add_object_address(CollationRelationId, con->constcollid, 0,
 							   context->addrs);
 
 		/*
@@ -1841,7 +1787,7 @@ find_expr_references_walker(Node *node,
 					objoid = DatumGetObjectId(con->constvalue);
 					if (SearchSysCacheExists1(PROCOID,
 											  ObjectIdGetDatum(objoid)))
-						add_object_address(OCLASS_PROC, objoid, 0,
+						add_object_address(ProcedureRelationId, objoid, 0,
 										   context->addrs);
 					break;
 				case REGOPEROID:
@@ -1849,42 +1795,42 @@ find_expr_references_walker(Node *node,
 					objoid = DatumGetObjectId(con->constvalue);
 					if (SearchSysCacheExists1(OPEROID,
 											  ObjectIdGetDatum(objoid)))
-						add_object_address(OCLASS_OPERATOR, objoid, 0,
+						add_object_address(OperatorRelationId, objoid, 0,
 										   context->addrs);
 					break;
 				case REGCLASSOID:
 					objoid = DatumGetObjectId(con->constvalue);
 					if (SearchSysCacheExists1(RELOID,
 											  ObjectIdGetDatum(objoid)))
-						add_object_address(OCLASS_CLASS, objoid, 0,
+						add_object_address(RelationRelationId, objoid, 0,
 										   context->addrs);
 					break;
 				case REGTYPEOID:
 					objoid = DatumGetObjectId(con->constvalue);
 					if (SearchSysCacheExists1(TYPEOID,
 											  ObjectIdGetDatum(objoid)))
-						add_object_address(OCLASS_TYPE, objoid, 0,
+						add_object_address(TypeRelationId, objoid, 0,
 										   context->addrs);
 					break;
 				case REGCOLLATIONOID:
 					objoid = DatumGetObjectId(con->constvalue);
 					if (SearchSysCacheExists1(COLLOID,
 											  ObjectIdGetDatum(objoid)))
-						add_object_address(OCLASS_COLLATION, objoid, 0,
+						add_object_address(CollationRelationId, objoid, 0,
 										   context->addrs);
 					break;
 				case REGCONFIGOID:
 					objoid = DatumGetObjectId(con->constvalue);
 					if (SearchSysCacheExists1(TSCONFIGOID,
 											  ObjectIdGetDatum(objoid)))
-						add_object_address(OCLASS_TSCONFIG, objoid, 0,
+						add_object_address(TSConfigRelationId, objoid, 0,
 										   context->addrs);
 					break;
 				case REGDICTIONARYOID:
 					objoid = DatumGetObjectId(con->constvalue);
 					if (SearchSysCacheExists1(TSDICTOID,
 											  ObjectIdGetDatum(objoid)))
-						add_object_address(OCLASS_TSDICT, objoid, 0,
+						add_object_address(TSDictionaryRelationId, objoid, 0,
 										   context->addrs);
 					break;
 
@@ -1892,7 +1838,7 @@ find_expr_references_walker(Node *node,
 					objoid = DatumGetObjectId(con->constvalue);
 					if (SearchSysCacheExists1(NAMESPACEOID,
 											  ObjectIdGetDatum(objoid)))
-						add_object_address(OCLASS_SCHEMA, objoid, 0,
+						add_object_address(NamespaceRelationId, objoid, 0,
 										   context->addrs);
 					break;
 
@@ -1915,19 +1861,19 @@ find_expr_references_walker(Node *node,
 		Param	   *param = (Param *) node;
 
 		/* A parameter must depend on the parameter's datatype */
-		add_object_address(OCLASS_TYPE, param->paramtype, 0,
+		add_object_address(TypeRelationId, param->paramtype, 0,
 						   context->addrs);
 		/* and its collation, just as for Consts */
 		if (OidIsValid(param->paramcollid) &&
 			param->paramcollid != DEFAULT_COLLATION_OID)
-			add_object_address(OCLASS_COLLATION, param->paramcollid, 0,
+			add_object_address(CollationRelationId, param->paramcollid, 0,
 							   context->addrs);
 	}
 	else if (IsA(node, FuncExpr))
 	{
 		FuncExpr   *funcexpr = (FuncExpr *) node;
 
-		add_object_address(OCLASS_PROC, funcexpr->funcid, 0,
+		add_object_address(ProcedureRelationId, funcexpr->funcid, 0,
 						   context->addrs);
 		/* fall through to examine arguments */
 	}
@@ -1935,7 +1881,7 @@ find_expr_references_walker(Node *node,
 	{
 		OpExpr	   *opexpr = (OpExpr *) node;
 
-		add_object_address(OCLASS_OPERATOR, opexpr->opno, 0,
+		add_object_address(OperatorRelationId, opexpr->opno, 0,
 						   context->addrs);
 		/* fall through to examine arguments */
 	}
@@ -1943,7 +1889,7 @@ find_expr_references_walker(Node *node,
 	{
 		DistinctExpr *distinctexpr = (DistinctExpr *) node;
 
-		add_object_address(OCLASS_OPERATOR, distinctexpr->opno, 0,
+		add_object_address(OperatorRelationId, distinctexpr->opno, 0,
 						   context->addrs);
 		/* fall through to examine arguments */
 	}
@@ -1951,7 +1897,7 @@ find_expr_references_walker(Node *node,
 	{
 		NullIfExpr *nullifexpr = (NullIfExpr *) node;
 
-		add_object_address(OCLASS_OPERATOR, nullifexpr->opno, 0,
+		add_object_address(OperatorRelationId, nullifexpr->opno, 0,
 						   context->addrs);
 		/* fall through to examine arguments */
 	}
@@ -1959,7 +1905,7 @@ find_expr_references_walker(Node *node,
 	{
 		ScalarArrayOpExpr *opexpr = (ScalarArrayOpExpr *) node;
 
-		add_object_address(OCLASS_OPERATOR, opexpr->opno, 0,
+		add_object_address(OperatorRelationId, opexpr->opno, 0,
 						   context->addrs);
 		/* fall through to examine arguments */
 	}
@@ -1967,7 +1913,7 @@ find_expr_references_walker(Node *node,
 	{
 		Aggref	   *aggref = (Aggref *) node;
 
-		add_object_address(OCLASS_PROC, aggref->aggfnoid, 0,
+		add_object_address(ProcedureRelationId, aggref->aggfnoid, 0,
 						   context->addrs);
 		/* fall through to examine arguments */
 	}
@@ -1975,7 +1921,7 @@ find_expr_references_walker(Node *node,
 	{
 		WindowFunc *wfunc = (WindowFunc *) node;
 
-		add_object_address(OCLASS_PROC, wfunc->winfnoid, 0,
+		add_object_address(ProcedureRelationId, wfunc->winfnoid, 0,
 						   context->addrs);
 		/* fall through to examine arguments */
 	}
@@ -1991,7 +1937,7 @@ find_expr_references_walker(Node *node,
 		 */
 		if (sbsref->refrestype != sbsref->refcontainertype &&
 			sbsref->refrestype != sbsref->refelemtype)
-			add_object_address(OCLASS_TYPE, sbsref->refrestype, 0,
+			add_object_address(TypeRelationId, sbsref->refrestype, 0,
 							   context->addrs);
 		/* fall through to examine arguments */
 	}
@@ -2016,15 +1962,15 @@ find_expr_references_walker(Node *node,
 		 * anywhere else in the expression.
 		 */
 		if (OidIsValid(reltype))
-			add_object_address(OCLASS_CLASS, reltype, fselect->fieldnum,
+			add_object_address(RelationRelationId, reltype, fselect->fieldnum,
 							   context->addrs);
 		else
-			add_object_address(OCLASS_TYPE, fselect->resulttype, 0,
+			add_object_address(TypeRelationId, fselect->resulttype, 0,
 							   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(fselect->resultcollid) &&
 			fselect->resultcollid != DEFAULT_COLLATION_OID)
-			add_object_address(OCLASS_COLLATION, fselect->resultcollid, 0,
+			add_object_address(CollationRelationId, fselect->resultcollid, 0,
 							   context->addrs);
 	}
 	else if (IsA(node, FieldStore))
@@ -2038,11 +1984,11 @@ find_expr_references_walker(Node *node,
 			ListCell   *l;
 
 			foreach(l, fstore->fieldnums)
-				add_object_address(OCLASS_CLASS, reltype, lfirst_int(l),
+				add_object_address(RelationRelationId, reltype, lfirst_int(l),
 								   context->addrs);
 		}
 		else
-			add_object_address(OCLASS_TYPE, fstore->resulttype, 0,
+			add_object_address(TypeRelationId, fstore->resulttype, 0,
 							   context->addrs);
 	}
 	else if (IsA(node, RelabelType))
@@ -2050,12 +1996,12 @@ find_expr_references_walker(Node *node,
 		RelabelType *relab = (RelabelType *) node;
 
 		/* since there is no function dependency, need to depend on type */
-		add_object_address(OCLASS_TYPE, relab->resulttype, 0,
+		add_object_address(TypeRelationId, relab->resulttype, 0,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(relab->resultcollid) &&
 			relab->resultcollid != DEFAULT_COLLATION_OID)
-			add_object_address(OCLASS_COLLATION, relab->resultcollid, 0,
+			add_object_address(CollationRelationId, relab->resultcollid, 0,
 							   context->addrs);
 	}
 	else if (IsA(node, CoerceViaIO))
@@ -2063,12 +2009,12 @@ find_expr_references_walker(Node *node,
 		CoerceViaIO *iocoerce = (CoerceViaIO *) node;
 
 		/* since there is no exposed function, need to depend on type */
-		add_object_address(OCLASS_TYPE, iocoerce->resulttype, 0,
+		add_object_address(TypeRelationId, iocoerce->resulttype, 0,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(iocoerce->resultcollid) &&
 			iocoerce->resultcollid != DEFAULT_COLLATION_OID)
-			add_object_address(OCLASS_COLLATION, iocoerce->resultcollid, 0,
+			add_object_address(CollationRelationId, iocoerce->resultcollid, 0,
 							   context->addrs);
 	}
 	else if (IsA(node, ArrayCoerceExpr))
@@ -2076,12 +2022,12 @@ find_expr_references_walker(Node *node,
 		ArrayCoerceExpr *acoerce = (ArrayCoerceExpr *) node;
 
 		/* as above, depend on type */
-		add_object_address(OCLASS_TYPE, acoerce->resulttype, 0,
+		add_object_address(TypeRelationId, acoerce->resulttype, 0,
 						   context->addrs);
 		/* the collation might not be referenced anywhere else, either */
 		if (OidIsValid(acoerce->resultcollid) &&
 			acoerce->resultcollid != DEFAULT_COLLATION_OID)
-			add_object_address(OCLASS_COLLATION, acoerce->resultcollid, 0,
+			add_object_address(CollationRelationId, acoerce->resultcollid, 0,
 							   context->addrs);
 		/* fall through to examine arguments */
 	}
@@ -2090,21 +2036,21 @@ find_expr_references_walker(Node *node,
 		ConvertRowtypeExpr *cvt = (ConvertRowtypeExpr *) node;
 
 		/* since there is no function dependency, need to depend on type */
-		add_object_address(OCLASS_TYPE, cvt->resulttype, 0,
+		add_object_address(TypeRelationId, cvt->resulttype, 0,
 						   context->addrs);
 	}
 	else if (IsA(node, CollateExpr))
 	{
 		CollateExpr *coll = (CollateExpr *) node;
 
-		add_object_address(OCLASS_COLLATION, coll->collOid, 0,
+		add_object_address(CollationRelationId, coll->collOid, 0,
 						   context->addrs);
 	}
 	else if (IsA(node, RowExpr))
 	{
 		RowExpr    *rowexpr = (RowExpr *) node;
 
-		add_object_address(OCLASS_TYPE, rowexpr->row_typeid, 0,
+		add_object_address(TypeRelationId, rowexpr->row_typeid, 0,
 						   context->addrs);
 	}
 	else if (IsA(node, RowCompareExpr))
@@ -2114,12 +2060,12 @@ find_expr_references_walker(Node *node,
 
 		foreach(l, rcexpr->opnos)
 		{
-			add_object_address(OCLASS_OPERATOR, lfirst_oid(l), 0,
+			add_object_address(OperatorRelationId, lfirst_oid(l), 0,
 							   context->addrs);
 		}
 		foreach(l, rcexpr->opfamilies)
 		{
-			add_object_address(OCLASS_OPFAMILY, lfirst_oid(l), 0,
+			add_object_address(OperatorFamilyRelationId, lfirst_oid(l), 0,
 							   context->addrs);
 		}
 		/* fall through to examine arguments */
@@ -2128,14 +2074,14 @@ find_expr_references_walker(Node *node,
 	{
 		CoerceToDomain *cd = (CoerceToDomain *) node;
 
-		add_object_address(OCLASS_TYPE, cd->resulttype, 0,
+		add_object_address(TypeRelationId, cd->resulttype, 0,
 						   context->addrs);
 	}
 	else if (IsA(node, NextValueExpr))
 	{
 		NextValueExpr *nve = (NextValueExpr *) node;
 
-		add_object_address(OCLASS_CLASS, nve->seqid, 0,
+		add_object_address(RelationRelationId, nve->seqid, 0,
 						   context->addrs);
 	}
 	else if (IsA(node, OnConflictExpr))
@@ -2143,7 +2089,7 @@ find_expr_references_walker(Node *node,
 		OnConflictExpr *onconflict = (OnConflictExpr *) node;
 
 		if (OidIsValid(onconflict->constraint))
-			add_object_address(OCLASS_CONSTRAINT, onconflict->constraint, 0,
+			add_object_address(ConstraintRelationId, onconflict->constraint, 0,
 							   context->addrs);
 		/* fall through to examine arguments */
 	}
@@ -2151,10 +2097,10 @@ find_expr_references_walker(Node *node,
 	{
 		SortGroupClause *sgc = (SortGroupClause *) node;
 
-		add_object_address(OCLASS_OPERATOR, sgc->eqop, 0,
+		add_object_address(OperatorRelationId, sgc->eqop, 0,
 						   context->addrs);
 		if (OidIsValid(sgc->sortop))
-			add_object_address(OCLASS_OPERATOR, sgc->sortop, 0,
+			add_object_address(OperatorRelationId, sgc->sortop, 0,
 							   context->addrs);
 		return false;
 	}
@@ -2163,14 +2109,14 @@ find_expr_references_walker(Node *node,
 		WindowClause *wc = (WindowClause *) node;
 
 		if (OidIsValid(wc->startInRangeFunc))
-			add_object_address(OCLASS_PROC, wc->startInRangeFunc, 0,
+			add_object_address(ProcedureRelationId, wc->startInRangeFunc, 0,
 							   context->addrs);
 		if (OidIsValid(wc->endInRangeFunc))
-			add_object_address(OCLASS_PROC, wc->endInRangeFunc, 0,
+			add_object_address(ProcedureRelationId, wc->endInRangeFunc, 0,
 							   context->addrs);
 		if (OidIsValid(wc->inRangeColl) &&
 			wc->inRangeColl != DEFAULT_COLLATION_OID)
-			add_object_address(OCLASS_COLLATION, wc->inRangeColl, 0,
+			add_object_address(CollationRelationId, wc->inRangeColl, 0,
 							   context->addrs);
 		/* fall through to examine substructure */
 	}
@@ -2179,13 +2125,13 @@ find_expr_references_walker(Node *node,
 		CTECycleClause *cc = (CTECycleClause *) node;
 
 		if (OidIsValid(cc->cycle_mark_type))
-			add_object_address(OCLASS_TYPE, cc->cycle_mark_type, 0,
+			add_object_address(TypeRelationId, cc->cycle_mark_type, 0,
 							   context->addrs);
 		if (OidIsValid(cc->cycle_mark_collation))
-			add_object_address(OCLASS_COLLATION, cc->cycle_mark_collation, 0,
+			add_object_address(CollationRelationId, cc->cycle_mark_collation, 0,
 							   context->addrs);
 		if (OidIsValid(cc->cycle_mark_neop))
-			add_object_address(OCLASS_OPERATOR, cc->cycle_mark_neop, 0,
+			add_object_address(OperatorRelationId, cc->cycle_mark_neop, 0,
 							   context->addrs);
 		/* fall through to examine substructure */
 	}
@@ -2219,7 +2165,7 @@ find_expr_references_walker(Node *node,
 			switch (rte->rtekind)
 			{
 				case RTE_RELATION:
-					add_object_address(OCLASS_CLASS, rte->relid, 0,
+					add_object_address(RelationRelationId, rte->relid, 0,
 									   context->addrs);
 					break;
 				case RTE_JOIN:
@@ -2277,7 +2223,7 @@ find_expr_references_walker(Node *node,
 
 					if (tle->resjunk)
 						continue;	/* ignore junk tlist items */
-					add_object_address(OCLASS_CLASS, rte->relid, tle->resno,
+					add_object_address(RelationRelationId, rte->relid, tle->resno,
 									   context->addrs);
 				}
 			}
@@ -2288,7 +2234,7 @@ find_expr_references_walker(Node *node,
 		 */
 		foreach(lc, query->constraintDeps)
 		{
-			add_object_address(OCLASS_CONSTRAINT, lfirst_oid(lc), 0,
+			add_object_address(ConstraintRelationId, lfirst_oid(lc), 0,
 							   context->addrs);
 		}
 
@@ -2322,7 +2268,7 @@ find_expr_references_walker(Node *node,
 		 */
 		foreach(ct, rtfunc->funccoltypes)
 		{
-			add_object_address(OCLASS_TYPE, lfirst_oid(ct), 0,
+			add_object_address(TypeRelationId, lfirst_oid(ct), 0,
 							   context->addrs);
 		}
 		foreach(ct, rtfunc->funccolcollations)
@@ -2330,7 +2276,7 @@ find_expr_references_walker(Node *node,
 			Oid			collid = lfirst_oid(ct);
 
 			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
-				add_object_address(OCLASS_COLLATION, collid, 0,
+				add_object_address(CollationRelationId, collid, 0,
 								   context->addrs);
 		}
 	}
@@ -2344,7 +2290,7 @@ find_expr_references_walker(Node *node,
 		 */
 		foreach(ct, tf->coltypes)
 		{
-			add_object_address(OCLASS_TYPE, lfirst_oid(ct), 0,
+			add_object_address(TypeRelationId, lfirst_oid(ct), 0,
 							   context->addrs);
 		}
 		foreach(ct, tf->colcollations)
@@ -2352,7 +2298,7 @@ find_expr_references_walker(Node *node,
 			Oid			collid = lfirst_oid(ct);
 
 			if (OidIsValid(collid) && collid != DEFAULT_COLLATION_OID)
-				add_object_address(OCLASS_COLLATION, collid, 0,
+				add_object_address(CollationRelationId, collid, 0,
 								   context->addrs);
 		}
 	}
@@ -2360,7 +2306,7 @@ find_expr_references_walker(Node *node,
 	{
 		TableSampleClause *tsc = (TableSampleClause *) node;
 
-		add_object_address(OCLASS_PROC, tsc->tsmhandler, 0,
+		add_object_address(ProcedureRelationId, tsc->tsmhandler, 0,
 						   context->addrs);
 		/* fall through to examine arguments */
 	}
@@ -2406,7 +2352,7 @@ process_function_rte_ref(RangeTblEntry *rte, AttrNumber attnum,
 
 				Assert(attnum - atts_done <= tupdesc->natts);
 				if (OidIsValid(reltype))	/* can this fail? */
-					add_object_address(OCLASS_CLASS, reltype,
+					add_object_address(RelationRelationId, reltype,
 									   attnum - atts_done,
 									   context->addrs);
 				return;
@@ -2553,12 +2499,9 @@ new_object_addresses(void)
 
 /*
  * Add an entry to an ObjectAddresses array.
- *
- * It is convenient to specify the class by ObjectClass rather than directly
- * by catalog OID.
  */
 static void
-add_object_address(ObjectClass oclass, Oid objectId, int32 subId,
+add_object_address(Oid classId, Oid objectId, int32 subId,
 				   ObjectAddresses *addrs)
 {
 	ObjectAddress *item;
@@ -2573,7 +2516,7 @@ add_object_address(ObjectClass oclass, Oid objectId, int32 subId,
 	}
 	/* record this item */
 	item = addrs->refs + addrs->numrefs;
-	item->classId = object_classes[oclass];
+	item->classId = classId;
 	item->objectId = objectId;
 	item->objectSubId = subId;
 	addrs->numrefs++;
@@ -2836,8 +2779,8 @@ free_object_addresses(ObjectAddresses *addrs)
 /*
  * Determine the class of a given object identified by objectAddress.
  *
- * This function is essentially the reverse mapping for the object_classes[]
- * table.  We implement it as a function because the OIDs aren't consecutive.
+ * We implement it as a function instead of an array because the OIDs aren't
+ * consecutive.
  */
 ObjectClass
 getObjectClass(const ObjectAddress *object)
diff --git a/src/include/catalog/dependency.h b/src/include/catalog/dependency.h
index fd588659014..436b081738b 100644
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@@ -83,7 +83,7 @@ typedef struct ObjectAddresses ObjectAddresses;
 
 /*
  * This enum covers all system catalogs whose OIDs can appear in
- * pg_depend.classId or pg_shdepend.classId.  Keep object_classes[] in sync.
+ * pg_depend.classId or pg_shdepend.classId.
  */
 typedef enum ObjectClass
 {
@@ -130,8 +130,6 @@ typedef enum ObjectClass
 	OCLASS_TRANSFORM,			/* pg_transform */
 } ObjectClass;
 
-#define LAST_OCLASS		OCLASS_TRANSFORM
-
 /* flag bits for performDeletion/performMultipleDeletions: */
 #define PERFORM_DELETION_INTERNAL			0x0001	/* internal action */
 #define PERFORM_DELETION_CONCURRENTLY		0x0002	/* concurrent drop */