Index: sys/sys/queue.h
===================================================================
RCS file: /cvsroot/src/sys/sys/queue.h,v
retrieving revision 1.55
diff -p -r1.55 queue.h
*** sys/sys/queue.h	17 Jul 2013 15:50:59 -0000	1.55
--- sys/sys/queue.h	16 Nov 2013 00:42:39 -0000
*************** struct {								\
*** 602,619 ****
  /*
   * Circular queue definitions.
   */
  #if defined(_KERNEL) && defined(QUEUEDEBUG)
  #define QUEUEDEBUG_CIRCLEQ_HEAD(head, field)				\
! 	if ((head)->cqh_first != (void *)(head) &&			\
! 	    (head)->cqh_first->field.cqe_prev != (void *)(head))	\
  		panic("CIRCLEQ head forw %p %s:%d", (head),		\
  		      __FILE__, __LINE__);				\
! 	if ((head)->cqh_last != (void *)(head) &&			\
! 	    (head)->cqh_last->field.cqe_next != (void *)(head))		\
  		panic("CIRCLEQ head back %p %s:%d", (head),		\
  		      __FILE__, __LINE__);
  #define QUEUEDEBUG_CIRCLEQ_ELM(head, elm, field)			\
! 	if ((elm)->field.cqe_next == (void *)(head)) {			\
  		if ((head)->cqh_last != (elm))				\
  			panic("CIRCLEQ elm last %p %s:%d", (elm),	\
  			      __FILE__, __LINE__);			\
--- 602,638 ----
  /*
   * Circular queue definitions.
   */
+ 
+ /*
+  * We use this ugly hack to work around the fact that the CIRCLEQ
+  * macros violate the C aliasing rules by comparing 'struct name *'
+  * and 'struct type *' (see CIRCLEQ_HEAD() below).  Modern compilers
+  * (such as GCC 4.8) declare this to be always false and this makes
+  * most of the macros below not function correctly.
+  *
+  * This hack is only to be used for comparisons and thus can be
+  * fully const.  Do not use for assignment.
+  */
+ static inline const void * __launder_type(const void *x);
+ static inline const void *
+ __launder_type(const void *x)
+ {
+ 	__asm volatile("" : "+r" (x));
+ 	return x;
+ }
+ 
  #if defined(_KERNEL) && defined(QUEUEDEBUG)
  #define QUEUEDEBUG_CIRCLEQ_HEAD(head, field)				\
! 	if ((head)->cqh_first != __launder_type(head) &&		\
! 	    (head)->cqh_first->field.cqe_prev != __launder_type(head))	\
  		panic("CIRCLEQ head forw %p %s:%d", (head),		\
  		      __FILE__, __LINE__);				\
! 	if ((head)->cqh_last != __launder_type(head) &&			\
! 	    (head)->cqh_last->field.cqe_next != __launder_type(head))	\
  		panic("CIRCLEQ head back %p %s:%d", (head),		\
  		      __FILE__, __LINE__);
  #define QUEUEDEBUG_CIRCLEQ_ELM(head, elm, field)			\
! 	if ((elm)->field.cqe_next == __launder_type(head)) {		\
  		if ((head)->cqh_last != (elm))				\
  			panic("CIRCLEQ elm last %p %s:%d", (elm),	\
  			      __FILE__, __LINE__);			\
*************** struct {								\
*** 622,628 ****
  			panic("CIRCLEQ elm forw %p %s:%d", (elm),	\
  			      __FILE__, __LINE__);			\
  	}								\
! 	if ((elm)->field.cqe_prev == (void *)(head)) {			\
  		if ((head)->cqh_first != (elm))				\
  			panic("CIRCLEQ elm first %p %s:%d", (elm),	\
  			      __FILE__, __LINE__);			\
--- 641,647 ----
  			panic("CIRCLEQ elm forw %p %s:%d", (elm),	\
  			      __FILE__, __LINE__);			\
  	}								\
! 	if ((elm)->field.cqe_prev == __launder_type(head)) {		\
  		if ((head)->cqh_first != (elm))				\
  			panic("CIRCLEQ elm first %p %s:%d", (elm),	\
  			      __FILE__, __LINE__);			\
*************** struct {								\
*** 668,674 ****
  	QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), field)		\
  	(elm)->field.cqe_next = (listelm)->field.cqe_next;		\
  	(elm)->field.cqe_prev = (listelm);				\
! 	if ((listelm)->field.cqe_next == (void *)(head))		\
  		(head)->cqh_last = (elm);				\
  	else								\
  		(listelm)->field.cqe_next->field.cqe_prev = (elm);	\
--- 687,693 ----
  	QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), field)		\
  	(elm)->field.cqe_next = (listelm)->field.cqe_next;		\
  	(elm)->field.cqe_prev = (listelm);				\
! 	if ((listelm)->field.cqe_next == __launder_type(head))		\
  		(head)->cqh_last = (elm);				\
  	else								\
  		(listelm)->field.cqe_next->field.cqe_prev = (elm);	\
*************** struct {								\
*** 680,686 ****
  	QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), field)		\
  	(elm)->field.cqe_next = (listelm);				\
  	(elm)->field.cqe_prev = (listelm)->field.cqe_prev;		\
! 	if ((listelm)->field.cqe_prev == (void *)(head))		\
  		(head)->cqh_first = (elm);				\
  	else								\
  		(listelm)->field.cqe_prev->field.cqe_next = (elm);	\
--- 699,705 ----
  	QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), field)		\
  	(elm)->field.cqe_next = (listelm);				\
  	(elm)->field.cqe_prev = (listelm)->field.cqe_prev;		\
! 	if ((listelm)->field.cqe_prev == __launder_type(head))		\
  		(head)->cqh_first = (elm);				\
  	else								\
  		(listelm)->field.cqe_prev->field.cqe_next = (elm);	\
*************** struct {								\
*** 690,697 ****
  #define	CIRCLEQ_INSERT_HEAD(head, elm, field) do {			\
  	QUEUEDEBUG_CIRCLEQ_HEAD((head), field)				\
  	(elm)->field.cqe_next = (head)->cqh_first;			\
! 	(elm)->field.cqe_prev = (void *)(head);				\
! 	if ((head)->cqh_last == (void *)(head))				\
  		(head)->cqh_last = (elm);				\
  	else								\
  		(head)->cqh_first->field.cqe_prev = (elm);		\
--- 709,716 ----
  #define	CIRCLEQ_INSERT_HEAD(head, elm, field) do {			\
  	QUEUEDEBUG_CIRCLEQ_HEAD((head), field)				\
  	(elm)->field.cqe_next = (head)->cqh_first;			\
! 	(elm)->field.cqe_prev = (void *)head;				\
! 	if ((head)->cqh_last == __launder_type(head))			\
  		(head)->cqh_last = (elm);				\
  	else								\
  		(head)->cqh_first->field.cqe_prev = (elm);		\
*************** struct {								\
*** 700,708 ****
  
  #define	CIRCLEQ_INSERT_TAIL(head, elm, field) do {			\
  	QUEUEDEBUG_CIRCLEQ_HEAD((head), field)				\
! 	(elm)->field.cqe_next = (void *)(head);				\
  	(elm)->field.cqe_prev = (head)->cqh_last;			\
! 	if ((head)->cqh_first == (void *)(head))			\
  		(head)->cqh_first = (elm);				\
  	else								\
  		(head)->cqh_last->field.cqe_next = (elm);		\
--- 719,727 ----
  
  #define	CIRCLEQ_INSERT_TAIL(head, elm, field) do {			\
  	QUEUEDEBUG_CIRCLEQ_HEAD((head), field)				\
! 	(elm)->field.cqe_next = (void *)head;				\
  	(elm)->field.cqe_prev = (head)->cqh_last;			\
! 	if ((head)->cqh_first == __launder_type(head))			\
  		(head)->cqh_first = (elm);				\
  	else								\
  		(head)->cqh_last->field.cqe_next = (elm);		\
*************** struct {								\
*** 712,723 ****
  #define	CIRCLEQ_REMOVE(head, elm, field) do {				\
  	QUEUEDEBUG_CIRCLEQ_HEAD((head), field)				\
  	QUEUEDEBUG_CIRCLEQ_ELM((head), (elm), field)			\
! 	if ((elm)->field.cqe_next == (void *)(head))			\
  		(head)->cqh_last = (elm)->field.cqe_prev;		\
  	else								\
  		(elm)->field.cqe_next->field.cqe_prev =			\
  		    (elm)->field.cqe_prev;				\
! 	if ((elm)->field.cqe_prev == (void *)(head))			\
  		(head)->cqh_first = (elm)->field.cqe_next;		\
  	else								\
  		(elm)->field.cqe_prev->field.cqe_next =			\
--- 731,742 ----
  #define	CIRCLEQ_REMOVE(head, elm, field) do {				\
  	QUEUEDEBUG_CIRCLEQ_HEAD((head), field)				\
  	QUEUEDEBUG_CIRCLEQ_ELM((head), (elm), field)			\
! 	if ((elm)->field.cqe_next == __launder_type(head))		\
  		(head)->cqh_last = (elm)->field.cqe_prev;		\
  	else								\
  		(elm)->field.cqe_next->field.cqe_prev =			\
  		    (elm)->field.cqe_prev;				\
! 	if ((elm)->field.cqe_prev == __launder_type(head))		\
  		(head)->cqh_first = (elm)->field.cqe_next;		\
  	else								\
  		(elm)->field.cqe_prev->field.cqe_next =			\
*************** struct {								\
*** 727,755 ****
  
  #define	CIRCLEQ_FOREACH(var, head, field)				\
  	for ((var) = ((head)->cqh_first);				\
! 		(var) != (const void *)(head);				\
  		(var) = ((var)->field.cqe_next))
  
  #define	CIRCLEQ_FOREACH_REVERSE(var, head, field)			\
  	for ((var) = ((head)->cqh_last);				\
! 		(var) != (const void *)(head);				\
  		(var) = ((var)->field.cqe_prev))
  
  /*
   * Circular queue access methods.
   */
! #define	CIRCLEQ_EMPTY(head)		((head)->cqh_first == (void *)(head))
  #define	CIRCLEQ_FIRST(head)		((head)->cqh_first)
  #define	CIRCLEQ_LAST(head)		((head)->cqh_last)
  #define	CIRCLEQ_NEXT(elm, field)	((elm)->field.cqe_next)
  #define	CIRCLEQ_PREV(elm, field)	((elm)->field.cqe_prev)
  
  #define CIRCLEQ_LOOP_NEXT(head, elm, field)				\
! 	(((elm)->field.cqe_next == (void *)(head))			\
  	    ? ((head)->cqh_first)					\
  	    : (elm->field.cqe_next))
  #define CIRCLEQ_LOOP_PREV(head, elm, field)				\
! 	(((elm)->field.cqe_prev == (void *)(head))			\
  	    ? ((head)->cqh_last)					\
  	    : (elm->field.cqe_prev))
  
--- 746,774 ----
  
  #define	CIRCLEQ_FOREACH(var, head, field)				\
  	for ((var) = ((head)->cqh_first);				\
! 		(var) != (const void *)__launder_type(head);		\
  		(var) = ((var)->field.cqe_next))
  
  #define	CIRCLEQ_FOREACH_REVERSE(var, head, field)			\
  	for ((var) = ((head)->cqh_last);				\
! 		(var) != (const void *)__launder_type(head);		\
  		(var) = ((var)->field.cqe_prev))
  
  /*
   * Circular queue access methods.
   */
! #define	CIRCLEQ_EMPTY(head)		((head)->cqh_first == __launder_type(head))
  #define	CIRCLEQ_FIRST(head)		((head)->cqh_first)
  #define	CIRCLEQ_LAST(head)		((head)->cqh_last)
  #define	CIRCLEQ_NEXT(elm, field)	((elm)->field.cqe_next)
  #define	CIRCLEQ_PREV(elm, field)	((elm)->field.cqe_prev)
  
  #define CIRCLEQ_LOOP_NEXT(head, elm, field)				\
! 	(((elm)->field.cqe_next == __launder_type(head))			\
  	    ? ((head)->cqh_first)					\
  	    : (elm->field.cqe_next))
  #define CIRCLEQ_LOOP_PREV(head, elm, field)				\
! 	(((elm)->field.cqe_prev == __launder_type(head))			\
  	    ? ((head)->cqh_last)					\
  	    : (elm->field.cqe_prev))