Index: includes/bootstrap.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/bootstrap.inc,v
retrieving revision 1.330
diff -u -p -r1.330 bootstrap.inc
--- includes/bootstrap.inc	22 Nov 2009 08:20:51 -0000	1.330
+++ includes/bootstrap.inc	28 Nov 2009 21:12:04 -0000
@@ -2156,16 +2156,33 @@ function registry_rebuild() {
  * function is called many times (100+) during a single page request, so
  * every microsecond of execution time that can be removed from the function
  * counts. These functions can use a more cumbersome, but faster variant of
- * calling drupal_static(). For benchmarks and background on this variant,
- * please see http://drupal.org/node/619666.
+ * calling drupal_static(). It works by storing the reference returned by
+ * drupal_static() in the calling function's own static variable, thereby
+ * removing the need to call drupal_static() for each iteration of the function.
+ * Conceptually, it replaces:
+ * @code
+ * $foo = &drupal_static(__FUNCTION__);
+ * @endcode
+ * with:
+ * @code
+ * // Unfortunately, this does not work.
+ * static $foo = &drupal_static(__FUNCTION__);
+ * @endcode
+ * However, the above line of code does not work, because PHP only allows static
+ * variables to be initializied by literal values, and does not allow static
+ * variables to be assigned to references.
+ * - http://php.net/manual/en/language.variables.scope.php#language.variables.scope.static
+ * - http://php.net/manual/en/language.variables.scope.php#language.variables.scope.references
+ * The example below shows the syntax needed to work around both limitations.
+ * For benchmarks and more information, @see http://drupal.org/node/619666.
  *
  * Example:
  * @code
  * function user_access($string, $account = NULL) {
  *   // Use the advanced drupal_static() pattern, since this is called very often.
- *   static $drupal_static = array();
- *   isset($drupal_static[__FUNCTION__]) || ($drupal_static[__FUNCTION__] = &drupal_static(__FUNCTION__));
- *   $perm = &$drupal_static[__FUNCTION__];
+ *   static $drupal_static;
+ *   isset($drupal_static) || ($drupal_static[0] = &drupal_static(__FUNCTION__));
+ *   $perm = &$drupal_static[0];
  *   ...
  * }
  * @endcode
Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.1052
diff -u -p -r1.1052 common.inc
--- includes/common.inc	26 Nov 2009 05:54:48 -0000	1.1052
+++ includes/common.inc	28 Nov 2009 21:12:04 -0000
@@ -2276,9 +2276,9 @@ function format_interval($timestamp, $gr
  */
 function format_date($timestamp, $type = 'medium', $format = '', $timezone = NULL, $langcode = NULL) {
   // Use the advanced drupal_static() pattern, since this is called very often.
-  static $drupal_static = array();
-  isset($drupal_static[__FUNCTION__]) || ($drupal_static[__FUNCTION__] = &drupal_static(__FUNCTION__));
-  $timezones = &$drupal_static[__FUNCTION__];
+  static $drupal_static;
+  isset($drupal_static) || ($drupal_static[0] = &drupal_static(__FUNCTION__));
+  $timezones = &$drupal_static[0];
 
   if (!isset($timezone)) {
     global $user;
@@ -2517,9 +2517,9 @@ function url($path = NULL, array $option
 
   global $base_url, $base_secure_url, $base_insecure_url;
   // Use the advanced drupal_static() pattern, since this is called very often.
-  static $drupal_static = array();
-  isset($drupal_static[__FUNCTION__]) || ($drupal_static[__FUNCTION__] = &drupal_static(__FUNCTION__));
-  $script = &$drupal_static[__FUNCTION__];
+  static $drupal_static;
+  isset($drupal_static) || ($drupal_static[0] = &drupal_static(__FUNCTION__));
+  $script = &$drupal_static[0];
 
   if (!isset($script)) {
     // On some web servers, such as IIS, we can't omit "index.php". So, we
@@ -4748,9 +4748,9 @@ function drupal_system_listing($mask, $d
  */
 function drupal_alter($type, &$data, &$context1 = NULL, &$context2 = NULL) {
   // Use the advanced drupal_static() pattern, since this is called very often.
-  static $drupal_static = array();
-  isset($drupal_static[__FUNCTION__]) || ($drupal_static[__FUNCTION__] = &drupal_static(__FUNCTION__));
-  $functions = &$drupal_static[__FUNCTION__];
+  static $drupal_static;
+  isset($drupal_static) || ($drupal_static[0] = &drupal_static(__FUNCTION__));
+  $functions = &$drupal_static[0];
 
   // Some alter hooks are invoked many times per page request, so statically
   // cache the list of functions to call, and on subsequent calls, iterate
@@ -6237,9 +6237,9 @@ function drupal_check_incompatibility($v
  */
 function entity_get_info($entity_type = NULL) {
   // Use the advanced drupal_static() pattern, since this is called very often.
-  static $drupal_static = array();
-  isset($drupal_static[__FUNCTION__]) || ($drupal_static[__FUNCTION__] = &drupal_static(__FUNCTION__));
-  $entity_info = &$drupal_static[__FUNCTION__];
+  static $drupal_static;
+  isset($drupal_static) || ($drupal_static[0] = &drupal_static(__FUNCTION__));
+  $entity_info = &$drupal_static[0];
 
   if (empty($entity_info)) {
     if ($cache = cache_get('entity_info')) {
Index: includes/module.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/module.inc,v
retrieving revision 1.175
diff -u -p -r1.175 module.inc
--- includes/module.inc	26 Nov 2009 18:57:16 -0000	1.175
+++ includes/module.inc	28 Nov 2009 21:12:04 -0000
@@ -450,9 +450,9 @@ function module_hook($module, $hook) {
  */
 function module_implements($hook, $sort = FALSE, $reset = FALSE) {
   // Use the advanced drupal_static() pattern, since this is called very often.
-  static $drupal_static = array();
-  isset($drupal_static[__FUNCTION__]) || ($drupal_static[__FUNCTION__] = &drupal_static(__FUNCTION__));
-  $implementations = &$drupal_static[__FUNCTION__];
+  static $drupal_static;
+  isset($drupal_static) || ($drupal_static[0] = &drupal_static(__FUNCTION__));
+  $implementations = &$drupal_static[0];
 
   // We maintain a persistent cache of hook implementations in addition to the
   // static cache to avoid looping through every module and every hook on each
Index: includes/path.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/path.inc,v
retrieving revision 1.48
diff -u -p -r1.48 path.inc
--- includes/path.inc	20 Nov 2009 06:12:45 -0000	1.48
+++ includes/path.inc	28 Nov 2009 21:12:04 -0000
@@ -46,9 +46,9 @@ function drupal_path_initialize() {
 function drupal_lookup_path($action, $path = '', $path_language = '') {
   global $language;
   // Use the advanced drupal_static() pattern, since this is called very often.
-  static $drupal_static = array();
-  isset($drupal_static[__FUNCTION__]) || ($drupal_static[__FUNCTION__] = &drupal_static(__FUNCTION__));
-  $cache = &$drupal_static[__FUNCTION__];
+  static $drupal_static;
+  isset($drupal_static) || ($drupal_static[0] = &drupal_static(__FUNCTION__));
+  $cache = &$drupal_static[0];
 
   if (!isset($cache)) {
     $cache = array(
@@ -257,9 +257,9 @@ function arg($index = NULL, $path = NULL
   // information), it should be resettable anyway in case a module needs to
   // free up the memory used by it.
   // Use the advanced drupal_static() pattern, since this is called very often.
-  static $drupal_static = array();
-  isset($drupal_static[__FUNCTION__]) || ($drupal_static[__FUNCTION__] = &drupal_static(__FUNCTION__));
-  $arguments = &$drupal_static[__FUNCTION__];
+  static $drupal_static;
+  isset($drupal_static) || ($drupal_static[0] = &drupal_static(__FUNCTION__));
+  $arguments = &$drupal_static[0];
 
   if (!isset($path)) {
     $path = $_GET['q'];
@@ -325,9 +325,9 @@ function drupal_set_title($title = NULL,
  */
 function drupal_is_front_page() {
   // Use the advanced drupal_static() pattern, since this is called very often.
-  static $drupal_static = array();
-  isset($drupal_static[__FUNCTION__]) || ($drupal_static[__FUNCTION__] = &drupal_static(__FUNCTION__));
-  $is_front_page = &$drupal_static[__FUNCTION__];
+  static $drupal_static;
+  isset($drupal_static) || ($drupal_static[0] = &drupal_static(__FUNCTION__));
+  $is_front_page = &$drupal_static[0];
 
   if (!isset($is_front_page)) {
     // As drupal_path_initialize updates $_GET['q'] with the 'site_frontpage' path,
Index: modules/user/user.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/user/user.module,v
retrieving revision 1.1084
diff -u -p -r1.1084 user.module
--- modules/user/user.module	22 Nov 2009 04:22:54 -0000	1.1084
+++ modules/user/user.module	28 Nov 2009 21:12:05 -0000
@@ -692,9 +692,9 @@ function user_access($string, $account =
   // To reduce the number of SQL queries, we cache the user's permissions
   // in a static variable.
   // Use the advanced drupal_static() pattern, since this is called very often.
-  static $drupal_static = array();
-  isset($drupal_static[__FUNCTION__]) || ($drupal_static[__FUNCTION__] = &drupal_static(__FUNCTION__));
-  $perm = &$drupal_static[__FUNCTION__];
+  static $drupal_static;
+  isset($drupal_static) || ($drupal_static[0] = &drupal_static(__FUNCTION__));
+  $perm = &$drupal_static[0];
   if (!isset($perm[$account->uid])) {
     $role_permissions = user_role_permissions($account->roles);