gh-100146: Steal references from stack when building a list #100147
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When executing the BUILD_LIST opcode, steal the references from the stack, in a manner similar to the BUILD_TUPLE opcode. Implement this by offloading the logic to a new private API, _PyList_FromArraySteal(), that works similarly to _PyTuple_FromArraySteal(). This way, instead of performing multiple stack pointer adjustments while the list is being initialized, the stack is adjusted only once and a fast memory copy operation is performed in one fell swoop.
gvanrossum
approved these changes
Dec 10, 2022
gvanrossum
added
the
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If you want to schedule another build, you need to add the " |
bedevere-bot
removed
the
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I've requested a buildbot build to make sure there isn't some dumb issue with refleaks. |
kumaraditya303
reviewed
Dec 10, 2022
| Improve ``BUILD_LIST`` opcode so that it works similarly to the | ||
| ``BUILD_TUPLE`` opcode, by stealing references from the stack rather than | ||
| repeatedly using stack operations to set list elements. Implementation | ||
| details are in a new private API :c:func:`_PyList_FromArraySteal`. |
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Suggested change
| details are in a new private API :c:func:`_PyList_FromArraySteal`. | |
| details are in a new private API :c:func:`!_PyList_FromArraySteal`. |
No need to link to private functions.
kumaraditya303
approved these changes
Dec 10, 2022
iritkatriel
reviewed
Dec 10, 2022
| Improve ``BUILD_LIST`` opcode so that it works similarly to the | ||
| ``BUILD_TUPLE`` opcode, by stealing references from the stack rather than |
There was a problem hiding this comment.
Suggested change
| Improve ``BUILD_LIST`` opcode so that it works similarly to the | |
| ``BUILD_TUPLE`` opcode, by stealing references from the stack rather than | |
| Improve :opcode:`BUILD_LIST` so that it works similarly to | |
| :opcode:`BUILD_TUPLE`, by stealing references from the stack rather than |
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I don't know what's up with the ARM64 Windows buildbot, but it's been failing the same way for at least three days, so no need to worry that this PR could somehow have made it go red. |
markshannon
reviewed
Dec 13, 2022
| PyObject * | ||
| _PyList_FromArraySteal(PyObject *const *src, Py_ssize_t n) | ||
| { | ||
| if (n == 0) { |
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When executing the BUILD_LIST opcode, steal the references from the stack, in a manner similar to the BUILD_TUPLE opcode. Implement this by offloading the logic to a new private API, _PyList_FromArraySteal(), that works similarly to _PyTuple_FromArraySteal().
This way, instead of performing multiple stack pointer adjustments while the list is being initialized, the stack is adjusted only once and a fast memory copy operation is performed in one fell swoop.