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colesbury
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gh-117139: Add header for tagged pointers (GH-118330)
 --------- Co-authored-by: Sam Gross <655866+colesbury@users.noreply.github.com>
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Diff for: ‎Include/internal/pycore_stackref.h

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,195 @@
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#ifndef Py_INTERNAL_STACKREF_H
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#define Py_INTERNAL_STACKREF_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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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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#include <stddef.h>
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typedef union {
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uintptr_t bits;
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} _PyStackRef;
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static const _PyStackRef Py_STACKREF_NULL = { .bits = 0 };
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#define Py_TAG_DEFERRED (1)
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// Gets a PyObject * from a _PyStackRef
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#if defined(Py_GIL_DISABLED)
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static inline PyObject *
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PyStackRef_Get(_PyStackRef tagged)
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{
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PyObject *cleared = ((PyObject *)((tagged).bits & (~Py_TAG_DEFERRED)));
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return cleared;
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}
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#else
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# define PyStackRef_Get(tagged) ((PyObject *)((tagged).bits))
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#endif
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// Converts a PyObject * to a PyStackRef, stealing the reference.
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#if defined(Py_GIL_DISABLED)
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static inline _PyStackRef
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_PyStackRef_StealRef(PyObject *obj)
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{
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// Make sure we don't take an already tagged value.
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assert(((uintptr_t)obj & Py_TAG_DEFERRED) == 0);
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return ((_PyStackRef){.bits = ((uintptr_t)(obj))});
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}
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# define PyStackRef_StealRef(obj) _PyStackRef_StealRef(_PyObject_CAST(obj))
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#else
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# define PyStackRef_StealRef(obj) ((_PyStackRef){.bits = ((uintptr_t)(obj))})
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#endif
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// Converts a PyObject * to a PyStackRef, with a new reference
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#if defined(Py_GIL_DISABLED)
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static inline _PyStackRef
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_PyStackRef_NewRefDeferred(PyObject *obj)
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{
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// Make sure we don't take an already tagged value.
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assert(((uintptr_t)obj & Py_TAG_DEFERRED) == 0);
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assert(obj != NULL);
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if (_PyObject_HasDeferredRefcount(obj)) {
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return (_PyStackRef){ .bits = (uintptr_t)obj | Py_TAG_DEFERRED };
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}
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else {
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return (_PyStackRef){ .bits = (uintptr_t)Py_NewRef(obj) };
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}
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}
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# define PyStackRef_NewRefDeferred(obj) _PyStackRef_NewRefDeferred(_PyObject_CAST(obj))
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#else
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# define PyStackRef_NewRefDeferred(obj) PyStackRef_NewRef(((_PyStackRef){.bits = ((uintptr_t)(obj))}))
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#endif
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#if defined(Py_GIL_DISABLED)
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static inline _PyStackRef
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_PyStackRef_XNewRefDeferred(PyObject *obj)
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{
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// Make sure we don't take an already tagged value.
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assert(((uintptr_t)obj & Py_TAG_DEFERRED) == 0);
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if (obj == NULL) {
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return Py_STACKREF_NULL;
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}
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return _PyStackRef_NewRefDeferred(obj);
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}
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# define PyStackRef_XNewRefDeferred(obj) _PyStackRef_XNewRefDeferred(_PyObject_CAST(obj))
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#else
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# define PyStackRef_XNewRefDeferred(obj) PyStackRef_XNewRef(((_PyStackRef){.bits = ((uintptr_t)(obj))}))
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#endif
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// Converts a PyStackRef back to a PyObject *.
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#if defined(Py_GIL_DISABLED)
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static inline PyObject *
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PyStackRef_StealObject(_PyStackRef tagged)
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{
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if ((tagged.bits & Py_TAG_DEFERRED) == Py_TAG_DEFERRED) {
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assert(_PyObject_HasDeferredRefcount(PyStackRef_Get(tagged)));
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return Py_NewRef(PyStackRef_Get(tagged));
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}
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return PyStackRef_Get(tagged);
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}
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#else
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# define PyStackRef_StealObject(tagged) PyStackRef_Get(tagged)
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#endif
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static inline void
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_Py_untag_stack_borrowed(PyObject **dst, const _PyStackRef *src, size_t length)
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{
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for (size_t i = 0; i < length; i++) {
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dst[i] = PyStackRef_Get(src[i]);
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}
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}
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static inline void
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_Py_untag_stack_steal(PyObject **dst, const _PyStackRef *src, size_t length)
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{
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for (size_t i = 0; i < length; i++) {
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dst[i] = PyStackRef_StealObject(src[i]);
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}
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}
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#define PyStackRef_XSETREF(dst, src) \
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do { \
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_PyStackRef *_tmp_dst_ptr = &(dst) \
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_PyStackRef _tmp_old_dst = (*_tmp_dst_ptr); \
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*_tmp_dst_ptr = (src); \
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PyStackRef_XDECREF(_tmp_old_dst); \
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} while (0)
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#define PyStackRef_SETREF(dst, src) \
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do { \
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_PyStackRef *_tmp_dst_ptr = &(dst); \
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_PyStackRef _tmp_old_dst = (*_tmp_dst_ptr); \
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*_tmp_dst_ptr = (src); \
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PyStackRef_DECREF(_tmp_old_dst); \
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} while (0)
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#define PyStackRef_CLEAR(op) \
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do { \
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_PyStackRef *_tmp_op_ptr = &(op); \
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_PyStackRef _tmp_old_op = (*_tmp_op_ptr); \
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if (_tmp_old_op.bits != Py_STACKREF_NULL.bits) { \
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*_tmp_op_ptr = Py_STACKREF_NULL; \
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PyStackRef_DECREF(_tmp_old_op); \
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} \
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} while (0)
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#if defined(Py_GIL_DISABLED)
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static inline void
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PyStackRef_DECREF(_PyStackRef tagged)
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{
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if ((tagged.bits & Py_TAG_DEFERRED) == Py_TAG_DEFERRED) {
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return;
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}
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Py_DECREF(PyStackRef_Get(tagged));
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}
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#else
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# define PyStackRef_DECREF(op) Py_DECREF(PyStackRef_Get(op))
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#endif
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#if defined(Py_GIL_DISABLED)
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static inline void
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PyStackRef_INCREF(_PyStackRef tagged)
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{
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if ((tagged.bits & Py_TAG_DEFERRED) == Py_TAG_DEFERRED) {
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assert(_PyObject_HasDeferredRefcount(PyStackRef_Get(tagged)));
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return;
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}
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Py_INCREF(PyStackRef_Get(tagged));
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}
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#else
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# define PyStackRef_INCREF(op) Py_INCREF(PyStackRef_Get(op))
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#endif
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static inline void
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PyStackRef_XDECREF(_PyStackRef op)
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{
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if (op.bits != Py_STACKREF_NULL.bits) {
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PyStackRef_DECREF(op);
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}
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}
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static inline _PyStackRef
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PyStackRef_NewRef(_PyStackRef obj)
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{
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PyStackRef_INCREF(obj);
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return obj;
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}
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static inline _PyStackRef
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PyStackRef_XNewRef(_PyStackRef obj)
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{
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if (obj.bits == Py_STACKREF_NULL.bits) {
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return obj;
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}
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return PyStackRef_NewRef(obj);
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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_STACKREF_H */

Diff for: ‎Makefile.pre.in

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@@ -1225,6 +1225,7 @@ PYTHON_HEADERS= \
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$(srcdir)/Include/internal/pycore_structseq.h \
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$(srcdir)/Include/internal/pycore_symtable.h \
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$(srcdir)/Include/internal/pycore_sysmodule.h \
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$(srcdir)/Include/internal/pycore_stackref.h \
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$(srcdir)/Include/internal/pycore_time.h \
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$(srcdir)/Include/internal/pycore_token.h \
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$(srcdir)/Include/internal/pycore_traceback.h \

Diff for: ‎PCbuild/pythoncore.vcxproj

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@@ -291,6 +291,7 @@
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<ClInclude Include="..\Include\internal\pycore_structseq.h" />
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<ClInclude Include="..\Include\internal\pycore_sysmodule.h" />
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<ClInclude Include="..\Include\internal\pycore_symtable.h" />
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<ClInclude Include="..\Include\internal\pycore_stackref.h" />
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<ClInclude Include="..\Include\internal\pycore_time.h" />
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<ClInclude Include="..\Include\internal\pycore_token.h" />
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<ClInclude Include="..\Include\internal\pycore_traceback.h" />

Diff for: ‎PCbuild/pythoncore.vcxproj.filters

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@@ -789,6 +789,9 @@
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<ClInclude Include="..\Include\internal\pycore_symtable.h">
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<Filter>Include\internal</Filter>
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</ClInclude>
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<ClInclude Include="..\Include\internal\pycore_stackref.h">
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<Filter>Include\internal</Filter>
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</ClInclude>
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<ClInclude Include="..\Include\internal\pycore_time.h">
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<Filter>Include\internal</Filter>
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</ClInclude>

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