gh-141510: Update specializer to support frozendict with BINARY_SUBSCR

[corona10]

We need to register frozendict for support in the specializer.

Since frozendict is only introduced in Python 3.15, it is not yet widely used. However, it is thread safe for many operations, including CALL_LEN and BINARY_OP_SUBSCR. It could also be optimized more aggressively in the JIT using KNOWN_CLASS optimizations in the pipeline.

This is just part of a draft PR. I am also happy to make _BINARY_OP_SUBSCR_FROZEN_DICT part of _BINARY_OP_SUBSCR_DICT, depending on what the JIT team prefers.

Without this PR, frozendict would be at a performance disadvantage, even though it is intended to be a first-class citizen alongside dict.

• Issue: PEP 814: Add built-in frozendict type #141510

[Sacul0457]

Would it be good if _GUARD_NOS_FROZEN_DICT was added to optimizer_bytecodes.c so that it could be removed by the optimizer if the type is known?

[Fidget-Spinner]

I think it's better to focus on getting the specializer correct in this PR for now. We can leave the JIT for another PR.

[corona10]

@Sacul0457 I think that we have to, I will update the PR or handle it at the seperate PR, but it needs feedback from JIT team first :)

[Fidget-Spinner]

This needs tests in test_opcache for the specialization success and failure case.

[corona10]

Once the PR is merged, I am also going to work on CONTAINS_OP_FROZENDICT too.

[corona10]

@Fidget-Spinner Now whole unit tests are passed.

[vstinner]

LGTM

[markshannon]

Do you have any evidence that this will improve performance?

Opcodes are a limited resource, and since no one is using frozen dicts yet, this is just going to slow down the interpreter by adding bulk.

Relaxing the guard in BINARY_OP_SUBSCR_DICT to check for any dict, and removing the redundant check in PyDict_GetItemRef would achieve your goal without lots of extra code or any slow down.

[corona10]

Relaxing the guard in BINARY_OP_SUBSCR_DICT to check for any dict, and removing the redundant check in PyDict_GetItemRef would achieve your goal without lots of extra code or any slow down.

I like that option too.

[vstinner]

@corona10 wrote #144949 to modify existing CONTAINS_OP_DICT and BINARY_OP_SUBSCR_DICT opcodes for frozendict. I close this PR.