gh-148571: [JIT] Preserve family-head recorder layouts for specialized opcode families#148730
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cocolato wants to merge 5 commits intopython:mainfrom
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gh-148571: [JIT] Preserve family-head recorder layouts for specialized opcode families#148730cocolato wants to merge 5 commits intopython:mainfrom
cocolato wants to merge 5 commits intopython:mainfrom
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cocolato
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Fidget-Spinner,
markshannon,
savannahostrowski and
tomasr8
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NekoAsakura
reviewed
Apr 18, 2026
| family_head = analysis.instructions[inst.family.name] | ||
| if family_head.properties.records_value: | ||
| source_inst = family_head | ||
| is_family_override = family_head is not inst |
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I think marking it as an override only when the member's recording differs from the head's is better than forcing GET_ITER through a redundant transformation.
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Yes, but more changes are needed. We might need to add a metadata mapping table for the family slot later on, which would also help us handle multi-record operations. Let’s wait for others to review this.
| uint8_t indices[MAX_RECORDED_VALUES]; | ||
| } _PyOpcodeRecordEntry; | ||
| PyAPI_DATA(const _PyOpcodeRecordEntry) _PyOpcode_RecordEntries[256]; | ||
| PyAPI_DATA(const uint8_t) _PyOpcode_RecordIsFamilyOverride[256]; |
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Refer: #148571 (comment)
TRACE_RECORDcaptures snapshot values before execution, but the bytecode subsequently translated into the trace may have been transformed into specialized ops within the same family.So if this specialized op inherits the recorder layout from the family head but actually requires a derived value—such as a type object, generator function, or bound method payload—a mismatch arises between the recorder layout and the consumption semantics.
The fix implemented in this change is as follows:
Have the base opcode of each affected family uniformly record the widest raw/base value required by the entire family, while leaving the semantics of existing
_RECORD_*uops unchanged. If a specialized family member still requires a derived view, the optimizer projects the raw recorded value into the form it actually needs to consume on-demand during the trace translation phase.Some related issues: #148716 #148618
recorded_valuesleak when specialized op deopts #148571