Fallback to first line of function when ex->opline is NULL

This can happen due to missing SAVE_OPLINE() in the VM

Author: arnaud-lb

Zend/zend_execute_API.c

@@ -627,6 +627,10 @@ ZEND_API uint32_t zend_get_executed_lineno(void) /* {{{ */
 		ex = ex->prev_execute_data;
 	}
 	if (ex) {
+		if (!ex->opline) {
+			/* Missing SAVE_OPLINE()? Falling back to first line of function */
+			return ex->func->op_array.opcodes[0].lineno;
+		}
 		if (EG(exception) && ex->opline->opcode == ZEND_HANDLE_EXCEPTION &&
 		    ex->opline->lineno == 0 && EG(opline_before_exception)) {
 			return EG(opline_before_exception)->lineno;