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22b0de2755
This PR sets up tagged pointers for CPython. The general idea is to create a separate struct _PyStackRef for everything on the evaluation stack to store the bits. This forces the C compiler to warn us if we try to cast things or pull things out of the struct directly. Only for free threading: We tag the low bit if something is deferred - that means we skip incref and decref operations on it. This behavior may change in the future if Mark's plans to defer all objects in the interpreter loop pans out. This implies a strict stack reference discipline is required. ALL incref and decref operations on stackrefs must use the stackref variants. It is unsafe to untag something then do normal incref/decref ops on it. The new incref and decref variants are called dup and close. They mimic a "handle" API operating on these stackrefs. Please read Include/internal/pycore_stackref.h for more information! --------- Co-authored-by: Mark Shannon <9448417+markshannon@users.noreply.github.com>
33 lines
756 B
C
33 lines
756 B
C
#ifndef Py_INTERNAL_OBJECT_DEFERRED_H
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#define Py_INTERNAL_OBJECT_DEFERRED_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include "pycore_gc.h"
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#ifndef Py_BUILD_CORE
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# error "this header requires Py_BUILD_CORE define"
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#endif
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// Mark an object as supporting deferred reference counting. This is a no-op
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// in the default (with GIL) build. Objects that use deferred reference
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// counting should be tracked by the GC so that they are eventually collected.
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extern void _PyObject_SetDeferredRefcount(PyObject *op);
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static inline int
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_PyObject_HasDeferredRefcount(PyObject *op)
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{
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#ifdef Py_GIL_DISABLED
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return _PyObject_HAS_GC_BITS(op, _PyGC_BITS_DEFERRED);
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#else
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return 0;
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#endif
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}
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#ifdef __cplusplus
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}
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#endif
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#endif // !Py_INTERNAL_OBJECT_DEFERRED_H
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