Extend `FOR_ITER` specializations to cover other indexable sequences
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- 主要語言
- Python
- 星號
- 77.2k
- 分支
- 35.9k
- PR 合併指標
- PR 指標待擷取
描述
Currently, we specialize FOR_ITER for both tuple and list. We also handle tuple and lists specially in GET_ITER to support this specialization.
We should extend this specialization of iteration over sequences, using virtual iterators to bytes, str, bytesarray and others.
To do this, we should:
- Add a
tp_getiteritemslots toPyTypeObjectfor sequences that can be efficiently indexed and cannot raise except for out-of-bounds access. - Add a specialization of
FOR_ITERfor these classes. - Specialize
GET_ITERfor:- iterators
- indexable sequences (those classes with a
tp_getiteritemslot)
- Specialize
SENDfor indexable sequences which should also improve JIT coverage, as unspecialized_SENDis currently a major cause of jit optimization failures.
Combined with https://github.com/python/cpython/issues/145667 this will allow effective specialization of a wider range of iterables and allow that specialization not only for for loops, but also for yield from loops.
It will add 3 instructions (4 new, 1 removed) which a reasonable
Linked PRs
- gh-145670
- gh-147967
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研究方向
先閱讀現有的 FOR_ITER 和 GET_ITER 特化,然後檢查 PyTypeObject 和 SEND 特化。當 bytes 和 str 等可索引序列在 for 迴圈和 yield from 迴圈中使用虛擬疊代器,並完成所要求的新指令涵蓋範圍時,這項工作就完成了。
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評估
- 技術堆疊
- python
- 領域
- compilers, performance
- Issue 類型
- 功能
- 難度
- 5/5
- 預估耗時
- 一週以上
- 活躍度
- 停滯
- 描述清晰度
- 需要釐清
- 新手友好度
- 20/100