sql: add OP_Error opcode in VDBE

This opcode is required to set an error using diag_set() without
halting VDBE. This will allow us to run destructors between error
setting and VDBE halting.

Needed for #4183

src/box/sql/build.c

@@ -1066,14 +1066,21 @@ vdbe_emit_ck_constraint_create(struct Parse *parser,
 		      sqlDbStrDup(db, ck_def->expr_str), P4_DYNAMIC);
 	sqlVdbeAddOp3(v, OP_MakeRecord, ck_constraint_reg, 5,
 		      ck_constraint_reg + 5);
-	const char *error_msg =
+	/* Check that there is no CHECK with such name. */
+	const char *err =
 		tt_sprintf(tnt_errcode_desc(ER_CONSTRAINT_EXISTS),
 					    ck_def->name);
-	if (vdbe_emit_halt_with_presence_test(parser, BOX_CK_CONSTRAINT_ID, 0,
-					      ck_constraint_reg, 2,
-					      ER_CONSTRAINT_EXISTS, error_msg,
-					      false, OP_NoConflict) != 0)
-		return;
+	int cursor = parser->nTab++;
+	vdbe_emit_open_cursor(parser, cursor, 0,
+			      space_by_id(BOX_CK_CONSTRAINT_ID));
+	sqlVdbeChangeP5(v, OPFLAG_SYSTEMSP);
+	sqlVdbeAddOp4Int(v, OP_NoConflict, cursor, v->nOp + 3,
+			 ck_constraint_reg, 2);
+	sqlVdbeAddOp4(v, OP_Error, ER_CONSTRAINT_EXISTS, v->nOp + 1, 0, err,
+		      P4_STATIC);
+	sqlVdbeAddOp1(v, OP_Halt, -1);
+	sqlVdbeAddOp1(v, OP_Close, cursor);
+
 	sqlVdbeAddOp3(v, OP_SInsert, BOX_CK_CONSTRAINT_ID, 0,
 		      ck_constraint_reg + 5);
 	save_record(parser, BOX_CK_CONSTRAINT_ID, ck_constraint_reg, 2,
@@ -1131,14 +1138,19 @@ vdbe_emit_fk_constraint_create(struct Parse *parse_context,
 	 * Lets check that constraint with this name hasn't
 	 * been created before.
 	 */
-	const char *error_msg =
+	const char *err =
 		tt_sprintf(tnt_errcode_desc(ER_CONSTRAINT_EXISTS), name_copy);
-	if (vdbe_emit_halt_with_presence_test(parse_context,
-					      BOX_FK_CONSTRAINT_ID, 0,
-					      constr_tuple_reg, 2,
-					      ER_CONSTRAINT_EXISTS, error_msg,
-					      false, OP_NoConflict) != 0)
-		return;
+	int cursor = parse_context->nTab++;
+	vdbe_emit_open_cursor(parse_context, cursor, 0,
+			      space_by_id(BOX_FK_CONSTRAINT_ID));
+	sqlVdbeChangeP5(vdbe, OPFLAG_SYSTEMSP);
+	sqlVdbeAddOp4Int(vdbe, OP_NoConflict, cursor, vdbe->nOp + 3,
+			 constr_tuple_reg, 2);
+	sqlVdbeAddOp4(vdbe, OP_Error, ER_CONSTRAINT_EXISTS, vdbe->nOp + 1, 0,
+		      err, P4_STATIC);
+	sqlVdbeAddOp1(vdbe, OP_Halt, -1);
+	sqlVdbeAddOp1(vdbe, OP_Close, cursor);
+
 	sqlVdbeAddOp2(vdbe, OP_Bool, fk->is_deferred, constr_tuple_reg + 3);
 	sqlVdbeAddOp4(vdbe, OP_String8, 0, constr_tuple_reg + 4, 0,
 			  fk_constraint_match_strs[fk->match], P4_STATIC);

src/box/sql/vdbe.c

@@ -885,6 +885,18 @@ case OP_Goto: {             /* jump */
 	goto jump_to_p2;
 }
 
+/* Opcode:  Error P1 P2 * P4 *
+ *
+ * Setting an error and an unconditional jump to address P2.
+ *
+ * The P1 parameter is error code of the erroe. The P4 parameter
+ * is a description of the error.
+ */
+case OP_Error: {             /* jump */
+	box_error_set(__FILE__, __LINE__, pOp->p1, pOp->p4.z);
+	goto jump_to_p2;
+}
+
 /* Opcode:  Gosub P1 P2 * * *
  *
  * Write the current address onto register P1