Index: src/wp-admin/link-parse-opml.php
===================================================================
--- src/wp-admin/link-parse-opml.php	(revision 38613)
+++ src/wp-admin/link-parse-opml.php	(working copy)
@@ -72,19 +72,24 @@
 }
 
 // Create an XML parser
-$xml_parser = xml_parser_create();
+if ( ! function_exists( 'xml_parser_create' ) ) {
+	trigger_error( __( "PHP's XML extension is not available. Please contact your hosting provider to enable PHP's XML extension." ) );
+}
+else {
+	$xml_parser = xml_parser_create();
 
-// Set the functions to handle opening and closing tags
-xml_set_element_handler($xml_parser, "startElement", "endElement");
+	// Set the functions to handle opening and closing tags
+	xml_set_element_handler($xml_parser, "startElement", "endElement");
 
-if ( ! xml_parse( $xml_parser, $opml, true ) ) {
-	printf(
-		/* translators: 1: error message, 2: line number */
-		__( 'XML Error: %1$s at line %2$s' ),
-		xml_error_string( xml_get_error_code( $xml_parser ) ),
-		xml_get_current_line_number( $xml_parser )
-	);
-}
+	if ( ! xml_parse( $xml_parser, $opml, true ) ) {
+		printf(
+			/* translators: 1: error message, 2: line number */
+			__( 'XML Error: %1$s at line %2$s' ),
+			xml_error_string( xml_get_error_code( $xml_parser ) ),
+			xml_get_current_line_number( $xml_parser )
+		);
+	}
 
-// Free up memory used by the XML parser
-xml_parser_free($xml_parser);
+	// Free up memory used by the XML parser
+	xml_parser_free($xml_parser);
+}
Index: src/wp-includes/IXR/class-IXR-message.php
===================================================================
--- src/wp-includes/IXR/class-IXR-message.php	(revision 38613)
+++ src/wp-includes/IXR/class-IXR-message.php	(working copy)
@@ -44,6 +44,11 @@
 
     function parse()
     {
+        if ( ! function_exists( 'xml_parser_create' ) ) { 
+            trigger_error( __( "PHP's XML extension is not available. Please contact your hosting provider to enable PHP's XML" ) ); 
+            return false;
+        }
+
         // first remove the XML declaration
         // merged from WP #10698 - this method avoids the RAM usage of preg_replace on very large messages
         $header = preg_replace( '/<\?xml.*?\?'.'>/s', '', substr( $this->message, 0, 100 ), 1 );
Index: src/wp-includes/atomlib.php
===================================================================
--- src/wp-includes/atomlib.php	(revision 38613)
+++ src/wp-includes/atomlib.php	(working copy)
@@ -121,6 +121,12 @@
 
         array_unshift($this->ns_contexts, array());
 
+        if ( ! function_exists( 'xml_parser_create_ns' ) ) {
+        	trigger_error( __( "PHP's XML extension is not available. Please contact your hosting provider to enable PHP's XML extension." ) );
+
+            return false;
+        }
+
         $parser = xml_parser_create_ns();
         xml_set_object($parser, $this);
         xml_set_element_handler($parser, "start_element", "end_element");
Index: src/wp-includes/feed.php
===================================================================
--- src/wp-includes/feed.php	(revision 38613)
+++ src/wp-includes/feed.php	(working copy)
@@ -538,6 +538,12 @@
 		return array('text', $data);
 	}
 
+	if ( ! function_exists( 'xml_parser_create' ) ) {
+		trigger_error( __( "PHP's XML extension is not available. Please contact your hosting provider to enable PHP's XML extension." ) );
+
+		return array('html', "<![CDATA[$data]]>");
+	}
+
 	$parser = xml_parser_create();
 	xml_parse($parser, '<div>' . $data . '</div>', true);
 	$code = xml_get_error_code($parser);
Index: src/wp-includes/rss.php
===================================================================
--- src/wp-includes/rss.php	(revision 38613)
+++ src/wp-includes/rss.php	(working copy)
@@ -60,15 +60,17 @@
 	 */
 	function __construct( $source ) {
 
-		# if PHP xml isn't compiled in, die
+		# Check if PHP xml isn't compiled
 		#
-		if ( !function_exists('xml_parser_create') )
-			trigger_error( "Failed to load PHP's XML Extension. https://secure.php.net/manual/en/ref.xml.php" );
+		if ( ! function_exists('xml_parser_create') ) {
+			return trigger_error( "Failed to load PHP's XML Extension. https://secure.php.net/manual/en/ref.xml.php" );
+		}
 
 		$parser = @xml_parser_create();
 
-		if ( !is_resource($parser) )
-			trigger_error( "Failed to create an instance of PHP's XML parser. https://secure.php.net/manual/en/ref.xml.php");
+		if ( ! is_resource($parser) ) {
+			return trigger_error( "Failed to create an instance of PHP's XML parser. https://secure.php.net/manual/en/ref.xml.php");
+		}
 
 		$this->parser = $parser;