ZJIT: Fix block_param_proxy_not_iseq_or_ifunc exits

[k0kubun]

On lobsters, block_param_proxy_not_iseq_or_ifunc seems like the 4th (counting both compile_error_register_spill_on_* as 1st) most frequent exits.

We need to:

1. Add stats to break down the types of block params to be supported
   • We need to add zjit_profile = true to getblockparamproxy, and profile block_handler for that instruction.
2. Fix unsupported block params
   • I suspect a lot of them are &nil, which is to be confirmed by (1).

[39bytes]

I went ahead and implemented profiling as mentioned in (1) and indeed a lot of the monomorphic cases are nil.

./run_benchmarks.rb --chruby 'ruby --zjit-stats' lobsters --once --turbo
...
Top-6 getblockparamproxy handler (100.0% of total 579,975):
  polymorphic: 384,798 (66.3%)
          nil: 123,016 (21.2%)
         iseq:  64,044 (11.0%)
  no_profiles:   6,267 ( 1.1%)
         proc:   1,607 ( 0.3%)
        ifunc:     243 ( 0.0%)
...

[k0kubun]

Nice! Thanks for the information.

[tekknolagi]

What should we be doing in the nil case?

[XrXr]

What should we be doing in the nil case?

Guard that it's nil and do the send as if send-without-block.

[39bytes]

Oops, I was working on this but forgot to assign myself, @rwstauner have you started on this already? If not I can put up what I have.
I think I have something working, cuts the side exits from block_param_proxy_not_iseq_or_ifunc by about half by handling the nil case

Master:

Top-20 side exit reasons (100.0% of total 15,338,047):
                   guard_type_failure: 6,889,030 (44.9%)
                  guard_shape_failure: 6,848,896 (44.7%)
  block_param_proxy_not_iseq_or_ifunc: 1,008,525 ( 6.6%)
                   unhandled_hir_insn:   236,975 ( 1.5%)

With fix:

Top-20 side exit reasons (100.0% of total 15,046,847):
                   guard_type_failure: 6,892,133 (45.8%)
                  guard_shape_failure: 6,848,904 (45.5%)
  block_param_proxy_not_iseq_or_ifunc:   549,807 ( 3.7%)
                   unhandled_hir_insn:   236,973 ( 1.6%)

[rwstauner]

I was just starting to take a look at it, but it sounds like you've made good progress so far, feel free to keep going or let me know how I can help