Added changes for default hit actions for tc backend

[Sosutha]

• Updated tc_may_override hint to be used with default_hit actions

• Added testcases for tc_may_override hint with default_hit action

[Sosutha]

@fruffy Could you approve this PR, PR is reviewed and approved from P4TC contributor. Need approval from a reviewer with merge access to merge the PR

[psivanup]

Looks fine to me

[fruffy]

@fruffy Could you approve this PR, PR is reviewed and approved from P4TC contributor. Need approval from a reviewer with merge access to merge the PR

I have invited komaljai to have write access to approve PRs.

[jafingerhut]

@Sosutha Out of curiosity, is there any public documentation, perhaps planned to be included in https://github.com/p4lang/p4c/blob/main/backends/tc/README.md, or linked to from that README, that explains the meanings and restrictions on use of these p4tc-specific annotations?

• @tc_type
• @tc_may_override
• @default_hit
• @default_hit_const
• @tc_acl
• @nummask

I may have missed some, but from some grep'ing through the test programs in testdata/p4tc_samples, those are the ones that I did not recognize as part of the language spec, nor in any public documentation I have come across so far.

[Sosutha]

@Sosutha Out of curiosity, is there any public documentation, perhaps planned to be included in https://github.com/p4lang/p4c/blob/main/backends/tc/README.md, or linked to from that README, that explains the meanings and restrictions on use of these p4tc-specific annotations?

• @tc_type
• @tc_may_override
• @default_hit
• @default_hit_const
• @tc_acl
• @nummask

I may have missed some, but from some grep'ing through the test programs in testdata/p4tc_samples, those are the ones that I did not recognize as part of the language spec, nor in any public documentation I have come across so far.

Right now, we do not have any public documentation. But we have plan to add one soon