From dc6b12d1b2ea26bb0323d932fa7b1a337eaca562 Mon Sep 17 00:00:00 2001 From: Ken Jin Date: Wed, 1 May 2024 04:46:13 +0800 Subject: [PATCH] gh-117139: Add header for tagged pointers (GH-118330) --------- Co-authored-by: Sam Gross <655866+colesbury@users.noreply.github.com> --- Include/internal/pycore_stackref.h | 195 +++++++++++++++++++++++++++++ Makefile.pre.in | 1 + PCbuild/pythoncore.vcxproj | 1 + PCbuild/pythoncore.vcxproj.filters | 3 + 4 files changed, 200 insertions(+) create mode 100644 Include/internal/pycore_stackref.h diff --git a/Include/internal/pycore_stackref.h b/Include/internal/pycore_stackref.h new file mode 100644 index 00000000000000..fd929cd4873a8b --- /dev/null +++ b/Include/internal/pycore_stackref.h @@ -0,0 +1,195 @@ +#ifndef Py_INTERNAL_STACKREF_H +#define Py_INTERNAL_STACKREF_H +#ifdef __cplusplus +extern "C" { +#endif + +#ifndef Py_BUILD_CORE +# error "this header requires Py_BUILD_CORE define" +#endif + +#include + +typedef union { + uintptr_t bits; +} _PyStackRef; + +static const _PyStackRef Py_STACKREF_NULL = { .bits = 0 }; + +#define Py_TAG_DEFERRED (1) + +// Gets a PyObject * from a _PyStackRef +#if defined(Py_GIL_DISABLED) +static inline PyObject * +PyStackRef_Get(_PyStackRef tagged) +{ + PyObject *cleared = ((PyObject *)((tagged).bits & (~Py_TAG_DEFERRED))); + return cleared; +} +#else +# define PyStackRef_Get(tagged) ((PyObject *)((tagged).bits)) +#endif + +// Converts a PyObject * to a PyStackRef, stealing the reference. +#if defined(Py_GIL_DISABLED) +static inline _PyStackRef +_PyStackRef_StealRef(PyObject *obj) +{ + // Make sure we don't take an already tagged value. + assert(((uintptr_t)obj & Py_TAG_DEFERRED) == 0); + return ((_PyStackRef){.bits = ((uintptr_t)(obj))}); +} +# define PyStackRef_StealRef(obj) _PyStackRef_StealRef(_PyObject_CAST(obj)) +#else +# define PyStackRef_StealRef(obj) ((_PyStackRef){.bits = ((uintptr_t)(obj))}) +#endif + +// Converts a PyObject * to a PyStackRef, with a new reference +#if defined(Py_GIL_DISABLED) +static inline _PyStackRef +_PyStackRef_NewRefDeferred(PyObject *obj) +{ + // Make sure we don't take an already tagged value. + assert(((uintptr_t)obj & Py_TAG_DEFERRED) == 0); + assert(obj != NULL); + if (_PyObject_HasDeferredRefcount(obj)) { + return (_PyStackRef){ .bits = (uintptr_t)obj | Py_TAG_DEFERRED }; + } + else { + return (_PyStackRef){ .bits = (uintptr_t)Py_NewRef(obj) }; + } +} +# define PyStackRef_NewRefDeferred(obj) _PyStackRef_NewRefDeferred(_PyObject_CAST(obj)) +#else +# define PyStackRef_NewRefDeferred(obj) PyStackRef_NewRef(((_PyStackRef){.bits = ((uintptr_t)(obj))})) +#endif + +#if defined(Py_GIL_DISABLED) +static inline _PyStackRef +_PyStackRef_XNewRefDeferred(PyObject *obj) +{ + // Make sure we don't take an already tagged value. + assert(((uintptr_t)obj & Py_TAG_DEFERRED) == 0); + if (obj == NULL) { + return Py_STACKREF_NULL; + } + return _PyStackRef_NewRefDeferred(obj); +} +# define PyStackRef_XNewRefDeferred(obj) _PyStackRef_XNewRefDeferred(_PyObject_CAST(obj)) +#else +# define PyStackRef_XNewRefDeferred(obj) PyStackRef_XNewRef(((_PyStackRef){.bits = ((uintptr_t)(obj))})) +#endif + +// Converts a PyStackRef back to a PyObject *. +#if defined(Py_GIL_DISABLED) +static inline PyObject * +PyStackRef_StealObject(_PyStackRef tagged) +{ + if ((tagged.bits & Py_TAG_DEFERRED) == Py_TAG_DEFERRED) { + assert(_PyObject_HasDeferredRefcount(PyStackRef_Get(tagged))); + return Py_NewRef(PyStackRef_Get(tagged)); + } + return PyStackRef_Get(tagged); +} +#else +# define PyStackRef_StealObject(tagged) PyStackRef_Get(tagged) +#endif + +static inline void +_Py_untag_stack_borrowed(PyObject **dst, const _PyStackRef *src, size_t length) +{ + for (size_t i = 0; i < length; i++) { + dst[i] = PyStackRef_Get(src[i]); + } +} + +static inline void +_Py_untag_stack_steal(PyObject **dst, const _PyStackRef *src, size_t length) +{ + for (size_t i = 0; i < length; i++) { + dst[i] = PyStackRef_StealObject(src[i]); + } +} + + +#define PyStackRef_XSETREF(dst, src) \ + do { \ + _PyStackRef *_tmp_dst_ptr = &(dst) \ + _PyStackRef _tmp_old_dst = (*_tmp_dst_ptr); \ + *_tmp_dst_ptr = (src); \ + PyStackRef_XDECREF(_tmp_old_dst); \ + } while (0) + +#define PyStackRef_SETREF(dst, src) \ + do { \ + _PyStackRef *_tmp_dst_ptr = &(dst); \ + _PyStackRef _tmp_old_dst = (*_tmp_dst_ptr); \ + *_tmp_dst_ptr = (src); \ + PyStackRef_DECREF(_tmp_old_dst); \ + } while (0) + +#define PyStackRef_CLEAR(op) \ + do { \ + _PyStackRef *_tmp_op_ptr = &(op); \ + _PyStackRef _tmp_old_op = (*_tmp_op_ptr); \ + if (_tmp_old_op.bits != Py_STACKREF_NULL.bits) { \ + *_tmp_op_ptr = Py_STACKREF_NULL; \ + PyStackRef_DECREF(_tmp_old_op); \ + } \ + } while (0) + +#if defined(Py_GIL_DISABLED) +static inline void +PyStackRef_DECREF(_PyStackRef tagged) +{ + if ((tagged.bits & Py_TAG_DEFERRED) == Py_TAG_DEFERRED) { + return; + } + Py_DECREF(PyStackRef_Get(tagged)); +} +#else +# define PyStackRef_DECREF(op) Py_DECREF(PyStackRef_Get(op)) +#endif + +#if defined(Py_GIL_DISABLED) +static inline void +PyStackRef_INCREF(_PyStackRef tagged) +{ + if ((tagged.bits & Py_TAG_DEFERRED) == Py_TAG_DEFERRED) { + assert(_PyObject_HasDeferredRefcount(PyStackRef_Get(tagged))); + return; + } + Py_INCREF(PyStackRef_Get(tagged)); +} +#else +# define PyStackRef_INCREF(op) Py_INCREF(PyStackRef_Get(op)) +#endif + +static inline void +PyStackRef_XDECREF(_PyStackRef op) +{ + if (op.bits != Py_STACKREF_NULL.bits) { + PyStackRef_DECREF(op); + } +} + +static inline _PyStackRef +PyStackRef_NewRef(_PyStackRef obj) +{ + PyStackRef_INCREF(obj); + return obj; +} + +static inline _PyStackRef +PyStackRef_XNewRef(_PyStackRef obj) +{ + if (obj.bits == Py_STACKREF_NULL.bits) { + return obj; + } + return PyStackRef_NewRef(obj); +} + +#ifdef __cplusplus +} +#endif +#endif /* !Py_INTERNAL_STACKREF_H */ diff --git a/Makefile.pre.in b/Makefile.pre.in index 4e4d01d14ee3cb..e69d1fe6e2dd14 100644 --- a/Makefile.pre.in +++ b/Makefile.pre.in @@ -1225,6 +1225,7 @@ PYTHON_HEADERS= \ $(srcdir)/Include/internal/pycore_structseq.h \ $(srcdir)/Include/internal/pycore_symtable.h \ $(srcdir)/Include/internal/pycore_sysmodule.h \ + $(srcdir)/Include/internal/pycore_stackref.h \ $(srcdir)/Include/internal/pycore_time.h \ $(srcdir)/Include/internal/pycore_token.h \ $(srcdir)/Include/internal/pycore_traceback.h \ diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj index 25d52945c1c330..4cb3e0d3227092 100644 --- a/PCbuild/pythoncore.vcxproj +++ b/PCbuild/pythoncore.vcxproj @@ -291,6 +291,7 @@ + diff --git a/PCbuild/pythoncore.vcxproj.filters b/PCbuild/pythoncore.vcxproj.filters index 4b1f9aa6538562..0b858cf1eb46a8 100644 --- a/PCbuild/pythoncore.vcxproj.filters +++ b/PCbuild/pythoncore.vcxproj.filters @@ -789,6 +789,9 @@ Include\internal + + Include\internal + Include\internal