gh-129068: allow concurrent iteration over range iterators

[tom-pytel]

Before anything, I'm not very familiar with the jit system so what I did to the ITER_RANGE micro-ops is maybe not in line with the master plan (In the sense of removing a uop, jit does run). But this PR does pass the test from: 1533d1d (which has been added here), and succeeds on the script from: #131199. TSAN also doesn't complain on them.

The fast range iterator has been made free-thread safe by reducing the state to a single variable, calculating the length each time it is needed is not horrible. Removed _ITER_JUMP_RANGE because the length guard needs to be atomic in _ITER_NEXT_RANGE, it can always be put back as a noop or extra check.

Removed the _PyObject_IsUniquelyReferenced() checks from FOR_ITER_RANGE opcode as they are no longer needed.

Took consideration of performance concern in: #129068, timings for this case are as follows:

gil old:       0.6393114424998203
gil new:       0.6314519609997660
gil newopt:    0.6323117769998134

nogil old:     0.7528951632993994
nogil new:     0.7935700326001097
nogil newopt:  0.6848774949000471  # opmitized "math"

New gil-enabled build is probably a little faster due to the removal of _ITER_JUMP_RANGE.

Script:

from timeit import timeit

t = timeit('for v in range_it: pass', 'range_it = range(100000)', number=1000)

print(f't: {t}')

Latest pyperformance bench gives 1% IMPROVEMENT for this PR in free-threaded over main (probably just variance).

There are three jit test_capi.test_opt tests which fail now, which looks like due to the changes to the micro-op behavior.

FAIL: test_for_iter_range (test.test_capi.test_opt.TestUops.test_for_iter_range)
AssertionError: '_GUARD_NOT_EXHAUSTED_RANGE' not found in ['_START_EXECUTOR', '_MAKE_WARM', '_SET_IP', '_CHECK_PERIODIC', '_CHECK_VALIDITY', '_ITER_CHECK_RANGE', '_ITER_NEXT_RANGE_TIER_TWO', 

FAIL: test_pop_jump_if_none (test.test_capi.test_opt.TestUops.test_pop_jump_if_none)
AssertionError: '_GUARD_IS_NOT_NONE_POP' unexpectedly found in ['_START_EXECUTOR', '_MAKE_WARM', '_SET_IP', '_CHECK_PERIODIC', '_CHECK_VALIDITY', '_ITER_CHECK_RANGE', 

FAIL: test_int_type_propagate_through_range (test.test_capi.test_opt.TestUopsOptimization.test_int_type_propagate_through_range)
AssertionError: '_GUARD_BOTH_INT' unexpectedly found in ['_START_EXECUTOR', '_MAKE_WARM', '_SET_IP', '_CHECK_PERIODIC', '_CHECK_VALIDITY', '_ITER_CHECK_RANGE', '_ITER_NEXT_RANGE_TIER_TWO', 

P.S. No idea why the "generated files up to date" test fails, I did regen-all.

• Issue: Race in concurrent iteration over range iterators #129068

[tom-pytel]

Ping @colesbury, @Yhg1s. Sorry to bug you guys with two PRs this weekend. Please consider this one an experiment and let me know if it is worth continuing with, and if so what would need to be changed?

[python-cla-bot]

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