diff options
| -rw-r--r-- | storage/maria/trnman.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/storage/maria/trnman.c b/storage/maria/trnman.c index b24203f4535..163305a1fb5 100644 --- a/storage/maria/trnman.c +++ b/storage/maria/trnman.c @@ -519,17 +519,24 @@ my_bool trnman_end_trn(TRN *trn, my_bool commit) */ void trnman_free_trn(TRN *trn) { - TRN *tmp= pool; + /* + union is to solve strict aliasing issue. + without it gcc 3.4.3 doesn't notice that updating *(void **)&tmp + modifies the value of tmp. + */ + union { TRN *trn; void *v; } tmp; + + tmp.trn= pool; my_atomic_rwlock_wrlock(&LOCK_pool); do { /* - without this volatile cast gcc-3.4.4 moved the assignment + without this volatile cast gcc-3.4.4 moves the assignment down after the loop at -O2 */ - *(TRN * volatile *)&(trn->next)= tmp; - } while (!my_atomic_casptr((void **)&pool, (void **)&tmp, trn)); + *(TRN * volatile *)&(trn->next)= tmp.trn; + } while (!my_atomic_casptr((void **)&pool, &tmp.v, trn)); my_atomic_rwlock_wrunlock(&LOCK_pool); } |