CLEANUP: fd: use a union in fd_rm_from_fd_list() to shut aliasing warnings

Enabling strict aliasing fails in fd.c when using the double-word CAS,
let's get rid of the (void**)(void*)&cur_list junk and use a union
instead. This way the compiler knows they do alias.

diff --git a/src/fd.c b/src/fd.c
index 5f432338ce17da6032a4dd6dc24900531d1b06ff..8eea0f5e9c17367ffae3a02717dd664eb78a1baf 100644 (file)
--- a/src/fd.c
+++ b/src/fd.c
@@ -179,7 +179,11 @@ done:
 void fd_rm_from_fd_list(volatile struct fdlist *list, int fd, int off)
 {
 #if defined(HA_HAVE_CAS_DW) || defined(HA_CAS_IS_8B)
-       volatile struct fdlist_entry cur_list, next_list;
+       volatile union {
+               struct fdlist_entry ent;
+               uint64_t u64;
+               uint32_t u32[2];
+       } cur_list, next_list;
 #endif
        int old;
        int new = -2;
@@ -188,24 +192,24 @@ void fd_rm_from_fd_list(volatile struct fdlist *list, int fd, int off)
        int last;
 lock_self:
 #if (defined(HA_CAS_IS_8B) || defined(HA_HAVE_CAS_DW))
-       next_list.next = next_list.prev = -2;
-       cur_list = *(volatile struct fdlist_entry *)(((char *)&fdtab[fd]) + off);
+       next_list.ent.next = next_list.ent.prev = -2;
+       cur_list.ent = *(volatile struct fdlist_entry *)(((char *)&fdtab[fd]) + off);
        /* First, attempt to lock our own entries */
        do {
                /* The FD is not in the FD cache, give up */
-               if (unlikely(cur_list.next <= -3))
+               if (unlikely(cur_list.ent.next <= -3))
                        return;
-               if (unlikely(cur_list.prev == -2 || cur_list.next == -2))
+               if (unlikely(cur_list.ent.prev == -2 || cur_list.ent.next == -2))
                        goto lock_self;
        } while (
 #ifdef HA_CAS_IS_8B
-           unlikely(!_HA_ATOMIC_CAS(((void **)(void *)&_GET_NEXT(fd, off)), ((void **)(void *)&cur_list), (*(void **)(void *)&next_list))))
+                unlikely(!_HA_ATOMIC_CAS(((uint64_t *)&_GET_NEXT(fd, off)), (uint64_t *)&cur_list.u64, next_list.u64))
 #else
-           unlikely(!_HA_ATOMIC_DWCAS(((void *)&_GET_NEXT(fd, off)), ((void *)&cur_list), ((void *)&next_list))))
+                unlikely(!_HA_ATOMIC_DWCAS(((long *)&_GET_NEXT(fd, off)), (uint32_t *)&cur_list.u32, &next_list.u32))
 #endif
-           ;
-       next = cur_list.next;
-       prev = cur_list.prev;
+           );
+       next = cur_list.ent.next;
+       prev = cur_list.ent.prev;
 
 #else
 lock_self_next: