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gh-131525: Cache the result of tuple_hash (#131529)

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* gh-131525: Cache the result of tuple_hash

* Fix debug builds

* Add blurb

* Fix formatting

* Pre-compute empty tuple singleton

* Mostly set the cache within tuple_alloc

* Fixes for TSAN

* Pre-compute empty tuple singleton

* Fix for 32-bit platforms

* Assert that op != NULL in _PyTuple_RESET_HASH_CACHE

* Use FT_ATOMIC_STORE_SSIZE_RELAXED macro

* Update Include/internal/pycore_tuple.h

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>

* Fix alignment

* atomic load

* Update Objects/tupleobject.c

Co-authored-by: Chris Eibl <138194463+chris-eibl@users.noreply.github.com>

---------

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Co-authored-by: Chris Eibl <138194463+chris-eibl@users.noreply.github.com>
This commit is contained in:
Michael Droettboom 2025-03-27 09:57:06 -04:00 • committed by GitHub
parent cf5e438c02
commit 8614f86b71
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102 changed files with 1218 additions and 183 deletions
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37
Include/internal/pycore_tuple.h
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@ -8,6 +8,7 @@ extern "C" {
# error "this header requires Py_BUILD_CORE define"
#endif
#include "pycore_object.h" // _PyObject_GC_IS_TRACKED
#include "pycore_structs.h" // _PyStackRef
extern void _PyTuple_MaybeUntrack(PyObject *);
@ -32,6 +33,42 @@ typedef struct {
PyTupleObject *it_seq; /* Set to NULL when iterator is exhausted */
} _PyTupleIterObject;
#define _PyTuple_RESET_HASH_CACHE(op) \
do { \
assert(op != NULL); \
_PyTuple_CAST(op)->ob_hash = -1; \
} while (0)
/* bpo-42536: If reusing a tuple object, this should be called to re-track it
with the garbage collector and reset its hash cache. */
static inline void
_PyTuple_Recycle(PyObject *op)
{
_PyTuple_RESET_HASH_CACHE(op);
if (!_PyObject_GC_IS_TRACKED(op)) {
_PyObject_GC_TRACK(op);
}
}
/* Below are the official constants from the xxHash specification. Optimizing
compilers should emit a single "rotate" instruction for the
_PyTuple_HASH_XXROTATE() expansion. If that doesn't happen for some important
platform, the macro could be changed to expand to a platform-specific rotate
spelling instead.
*/
#if SIZEOF_PY_UHASH_T > 4
#define _PyTuple_HASH_XXPRIME_1 ((Py_uhash_t)11400714785074694791ULL)
#define _PyTuple_HASH_XXPRIME_2 ((Py_uhash_t)14029467366897019727ULL)
#define _PyTuple_HASH_XXPRIME_5 ((Py_uhash_t)2870177450012600261ULL)
#define _PyTuple_HASH_XXROTATE(x) ((x << 31) | (x >> 33)) /* Rotate left 31 bits */
#else
#define _PyTuple_HASH_XXPRIME_1 ((Py_uhash_t)2654435761UL)
#define _PyTuple_HASH_XXPRIME_2 ((Py_uhash_t)2246822519UL)
#define _PyTuple_HASH_XXPRIME_5 ((Py_uhash_t)374761393UL)
#define _PyTuple_HASH_XXROTATE(x) ((x << 13) | (x >> 19)) /* Rotate left 13 bits */
#endif
#define _PyTuple_HASH_EMPTY (_PyTuple_HASH_XXPRIME_5 + (_PyTuple_HASH_XXPRIME_5 ^ 3527539UL))
#ifdef __cplusplus
}
#endif