Does current table_executor consider default action reachability?

[RabbitWhite1]

The current implementation of table_executor adds reachability for each action here. But the expression actionHitCondition is constructed with new IR::LAnd(hitCondition, actionChoice), where hitCondition is for key matching and actionChoice is for action name.

But for default actions, shall we add something like "if none of the actions matched, the default action will be reached"?

The reason I am thinking of this is that I noticed the removing for tna_operations.p4 looks incorrect. For example, if a packet misses on table forward, it should be dropped by executing default action miss. But since forward.apply() is removed, it won't be dropped.

[fruffy]

This is a bug in the dead code eliminator, less so in the analysis. It used to be the case that only NoAction was removed, but we should instead substitute the apply call with the default action instead if a table is removed.

[RabbitWhite1]

I see. I found that defaultonly actions are filtered out in the dead code eliminator. Can we simply transform the apply call to the default action call right before here if the default action for this table is specified?

[fruffy]

Yes, we basically retrieve the default action from the table. We can check whether the body is empty, too.

[RabbitWhite1]

Great. I will submit a pr to fix this.

[RabbitWhite1]

Fixed by #56. Also updated reference files. PTAL @fruffy