diff options
| -rw-r--r-- | src/db.c | 44 |
1 files changed, 44 insertions, 0 deletions
@@ -825,6 +825,38 @@ int db_syscall_priority(struct db_filter *db, } /** + * Test if the argument filter can be skipped because it's a tautology + * @param arg argument filter + * + * If this argument filter applied to the lower 32 bit can be skipped this + * function returns false. + * + */ +static bool _db_arg_cmp_need_lo(const struct db_api_arg *arg) +{ + if (arg->op == SCMP_CMP_MASKED_EQ && D64_LO(arg->mask) == 0) + return false; + + return true; +} + +/** + * Test if the argument filter can be skipped because it's a tautology + * @param arg argument filter + * + * If this argument filter applied to the upper 32 bit can be skipped this + * function returns false. + * + */ +static bool _db_arg_cmp_need_hi(const struct db_api_arg *arg) +{ + if (arg->op == SCMP_CMP_MASKED_EQ && D64_HI(arg->mask) == 0) + return false; + + return true; +} + +/** * Fixup the node based on the op/mask * @param node the chain node * @@ -873,6 +905,13 @@ static struct db_sys_list *_db_rule_gen_64(const struct arch_def *arch, if (chain[iter].valid == 0) continue; + /* TODO: handle the case were either hi or lo isn't needed */ + + /* skip generating instruction which are no-ops */ + if (!_db_arg_cmp_need_hi(&chain[iter]) && + !_db_arg_cmp_need_lo(&chain[iter])) + continue; + c_iter_hi = malloc(sizeof(*c_iter_hi)); if (c_iter_hi == NULL) goto gen_64_failure; @@ -1005,6 +1044,10 @@ static struct db_sys_list *_db_rule_gen_32(const struct arch_def *arch, if (chain[iter].valid == 0) continue; + /* skip generating instructions which are no-ops */ + if (!_db_arg_cmp_need_lo(&chain[iter])) + continue; + c_iter = malloc(sizeof(*c_iter)); if (c_iter == NULL) goto gen_32_failure; @@ -1013,6 +1056,7 @@ static struct db_sys_list *_db_rule_gen_32(const struct arch_def *arch, c_iter->arg = chain[iter].arg; c_iter->arg_offset = arch_arg_offset(arch, c_iter->arg); c_iter->op = chain[iter].op; + /* implicitly strips off the upper 32 bit */ c_iter->mask = chain[iter].mask; c_iter->datum = chain[iter].datum; |