<?
function getBreadcrumbs( $post, $arr ) {

    array_push( $arr, ['title' => $post->post_title, 'id' => $post->ID] );

    if ( $post->post_parent !== 0 ) {
        $child_post = $post->post_parent;

        return getBreadcrumbs( get_post( $child_post ), $arr );
    }

    return array_reverse( $arr );
}

?>

<? $breadcrumbs = getBreadcrumbs( $post, [] ); ?>

<? foreach ( $breadcrumbs as $index => $breadcrumb ) : ?>

    <a href="<?= get_permalink( $breadcrumb['id'] ); ?>">
    <?= $breadcrumb['title']; ?>
        <? if ( $index < count( $breadcrumbs ) - 1 ): ?>
            <span class="o-breadcrumbs__arrow">&raquo;</span>
        <? endif; ?>
    </a>
<? endforeach; ?>