Revert: bpo-33608: Factor out a private, per-interpreter _Py_AddPendingCall()....

Revert: bpo-33608: Factor out a private, per-interpreter _Py_AddPendingCall(). (GH-11617) (GH-12159)

* Revert "bpo-36097: Use only public C-API in the_xxsubinterpreters module (adding as necessary). (#12003)"

This reverts commit bcfa450f.

* Revert "bpo-33608: Simplify ceval's DISPATCH by hoisting eval_breaker ahead of time. (gh-12062)"

This reverts commit bda918bf.

* Revert "bpo-33608: Use _Py_AddPendingCall() in _PyCrossInterpreterData_Release(). (gh-12024)"

This reverts commit b05b711a.

* Revert "bpo-33608: Factor out a private, per-interpreter _Py_AddPendingCall(). (GH-11617)"

This reverts commit ef4ac967.

Include/ceval.h

@@ -221,7 +221,7 @@ PyAPI_FUNC(Py_ssize_t) _PyEval_RequestCodeExtraIndex(freefunc);
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(int) _PyEval_SliceIndex(PyObject *, Py_ssize_t *);
 PyAPI_FUNC(int) _PyEval_SliceIndexNotNone(PyObject *, Py_ssize_t *);
-PyAPI_FUNC(void) _PyEval_SignalAsyncExc(PyInterpreterState *);
+PyAPI_FUNC(void) _PyEval_SignalAsyncExc(void);
 #endif
 
 /* Masks and values used by FORMAT_VALUE opcode. */

Include/cpython/interpreteridobject.h

-#ifndef Py_CPYTHON_INTERPRETERIDOBJECT_H
-#  error "this header file must not be included directly"
-#endif
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/* Interpreter ID Object */
-
-PyAPI_DATA(PyTypeObject) _PyInterpreterID_Type;
-
-PyAPI_FUNC(PyObject *) _PyInterpreterID_New(int64_t);
-PyAPI_FUNC(PyObject *) _PyInterpreterState_GetIDObject(PyInterpreterState *);
-PyAPI_FUNC(PyInterpreterState *) _PyInterpreterID_LookUp(PyObject *);
-
-PyAPI_FUNC(int64_t) _Py_CoerceID(PyObject *);
-
-#ifdef __cplusplus
-}
-#endif

Include/cpython/pystate.h

@@ -30,13 +30,9 @@ typedef struct {
     (_PyMainInterpreterConfig){.install_signal_handlers = -1}
 /* Note: _PyMainInterpreterConfig_INIT sets other fields to 0/NULL */
 
-PyAPI_FUNC(int) _PyInterpreterState_RequiresIDRef(PyInterpreterState *);
-PyAPI_FUNC(void) _PyInterpreterState_RequireIDRef(PyInterpreterState *, int);
-
 PyAPI_FUNC(_PyCoreConfig *) _PyInterpreterState_GetCoreConfig(PyInterpreterState *);
 PyAPI_FUNC(_PyMainInterpreterConfig *) _PyInterpreterState_GetMainConfig(PyInterpreterState *);
 
-PyAPI_FUNC(PyObject *) _PyInterpreterState_GetMainModule(PyInterpreterState *);
 
 /* State unique per thread */
 
@@ -218,65 +214,6 @@ PyAPI_FUNC(PyThreadState *) PyThreadState_Next(PyThreadState *);
 
 typedef struct _frame *(*PyThreadFrameGetter)(PyThreadState *self_);
 
-/* cross-interpreter data */
-
-struct _xid;
-
-// _PyCrossInterpreterData is similar to Py_buffer as an effectively
-// opaque struct that holds data outside the object machinery.  This
-// is necessary to pass safely between interpreters in the same process.
-typedef struct _xid {
-    // data is the cross-interpreter-safe derivation of a Python object
-    // (see _PyObject_GetCrossInterpreterData).  It will be NULL if the
-    // new_object func (below) encodes the data.
-    void *data;
-    // obj is the Python object from which the data was derived.  This
-    // is non-NULL only if the data remains bound to the object in some
-    // way, such that the object must be "released" (via a decref) when
-    // the data is released.  In that case the code that sets the field,
-    // likely a registered "crossinterpdatafunc", is responsible for
-    // ensuring it owns the reference (i.e. incref).
-    PyObject *obj;
-    // interp is the ID of the owning interpreter of the original
-    // object.  It corresponds to the active interpreter when
-    // _PyObject_GetCrossInterpreterData() was called.  This should only
-    // be set by the cross-interpreter machinery.
-    //
-    // We use the ID rather than the PyInterpreterState to avoid issues
-    // with deleted interpreters.  Note that IDs are never re-used, so
-    // each one will always correspond to a specific interpreter
-    // (whether still alive or not).
-    int64_t interp;
-    // new_object is a function that returns a new object in the current
-    // interpreter given the data.  The resulting object (a new
-    // reference) will be equivalent to the original object.  This field
-    // is required.
-    PyObject *(*new_object)(struct _xid *);
-    // free is called when the data is released.  If it is NULL then
-    // nothing will be done to free the data.  For some types this is
-    // okay (e.g. bytes) and for those types this field should be set
-    // to NULL.  However, for most the data was allocated just for
-    // cross-interpreter use, so it must be freed when
-    // _PyCrossInterpreterData_Release is called or the memory will
-    // leak.  In that case, at the very least this field should be set
-    // to PyMem_RawFree (the default if not explicitly set to NULL).
-    // The call will happen with the original interpreter activated.
-    void (*free)(void *);
-} _PyCrossInterpreterData;
-
-PyAPI_FUNC(int) _PyObject_GetCrossInterpreterData(PyObject *, _PyCrossInterpreterData *);
-PyAPI_FUNC(PyObject *) _PyCrossInterpreterData_NewObject(_PyCrossInterpreterData *);
-PyAPI_FUNC(void) _PyCrossInterpreterData_Release(_PyCrossInterpreterData *);
-
-PyAPI_FUNC(int) _PyObject_CheckCrossInterpreterData(PyObject *);
-
-/* cross-interpreter data registry */
-
-typedef int (*crossinterpdatafunc)(PyObject *, struct _xid *);
-
-PyAPI_FUNC(int) _PyCrossInterpreterData_RegisterClass(PyTypeObject *, crossinterpdatafunc);
-PyAPI_FUNC(crossinterpdatafunc) _PyCrossInterpreterData_Lookup(PyObject *);
-
 #ifdef __cplusplus
 }
 #endif

Include/internal/pycore_atomic.h

@@ -58,10 +58,10 @@ typedef struct _Py_atomic_int {
     atomic_thread_fence(ORDER)
 
 #define _Py_atomic_store_explicit(ATOMIC_VAL, NEW_VAL, ORDER) \
-    atomic_store_explicit(&((ATOMIC_VAL)->_value), NEW_VAL, ORDER)
+    atomic_store_explicit(&(ATOMIC_VAL)->_value, NEW_VAL, ORDER)
 
 #define _Py_atomic_load_explicit(ATOMIC_VAL, ORDER) \
-    atomic_load_explicit(&((ATOMIC_VAL)->_value), ORDER)
+    atomic_load_explicit(&(ATOMIC_VAL)->_value, ORDER)
 
 /* Use builtin atomic operations in GCC >= 4.7 */
 #elif defined(HAVE_BUILTIN_ATOMIC)
@@ -92,14 +92,14 @@ typedef struct _Py_atomic_int {
     (assert((ORDER) == __ATOMIC_RELAXED                       \
             || (ORDER) == __ATOMIC_SEQ_CST                    \
             || (ORDER) == __ATOMIC_RELEASE),                  \
-     __atomic_store_n(&((ATOMIC_VAL)->_value), NEW_VAL, ORDER))
+     __atomic_store_n(&(ATOMIC_VAL)->_value, NEW_VAL, ORDER))
 
 #define _Py_atomic_load_explicit(ATOMIC_VAL, ORDER)           \
     (assert((ORDER) == __ATOMIC_RELAXED                       \
             || (ORDER) == __ATOMIC_SEQ_CST                    \
             || (ORDER) == __ATOMIC_ACQUIRE                    \
             || (ORDER) == __ATOMIC_CONSUME),                  \
-     __atomic_load_n(&((ATOMIC_VAL)->_value), ORDER))
+     __atomic_load_n(&(ATOMIC_VAL)->_value, ORDER))
 
 /* Only support GCC (for expression statements) and x86 (for simple
  * atomic semantics) and MSVC x86/x64/ARM */
@@ -324,7 +324,7 @@ inline intptr_t _Py_atomic_load_64bit(volatile uintptr_t* value, int order) {
 }
 
 #else
-#define _Py_atomic_load_64bit(ATOMIC_VAL, ORDER) *(ATOMIC_VAL)
+#define _Py_atomic_load_64bit(ATOMIC_VAL, ORDER) *ATOMIC_VAL
 #endif
 
 inline int _Py_atomic_load_32bit(volatile int* value, int order) {
@@ -359,15 +359,15 @@ inline int _Py_atomic_load_32bit(volatile int* value, int order) {
 }
 
 #define _Py_atomic_store_explicit(ATOMIC_VAL, NEW_VAL, ORDER) \
-  if (sizeof((ATOMIC_VAL)->_value) == 8) { \
-    _Py_atomic_store_64bit((volatile long long*)&((ATOMIC_VAL)->_value), NEW_VAL, ORDER) } else { \
-    _Py_atomic_store_32bit((volatile long*)&((ATOMIC_VAL)->_value), NEW_VAL, ORDER) }
+  if (sizeof(*ATOMIC_VAL._value) == 8) { \
+    _Py_atomic_store_64bit((volatile long long*)ATOMIC_VAL._value, NEW_VAL, ORDER) } else { \
+    _Py_atomic_store_32bit((volatile long*)ATOMIC_VAL._value, NEW_VAL, ORDER) }
 
 #define _Py_atomic_load_explicit(ATOMIC_VAL, ORDER) \
   ( \
-    sizeof((ATOMIC_VAL)->_value) == 8 ? \
-    _Py_atomic_load_64bit((volatile long long*)&((ATOMIC_VAL)->_value), ORDER) : \
-    _Py_atomic_load_32bit((volatile long*)&((ATOMIC_VAL)->_value), ORDER) \
+    sizeof(*(ATOMIC_VAL._value)) == 8 ? \
+    _Py_atomic_load_64bit((volatile long long*)ATOMIC_VAL._value, ORDER) : \
+    _Py_atomic_load_32bit((volatile long*)ATOMIC_VAL._value, ORDER) \
   )
 #elif defined(_M_ARM) || defined(_M_ARM64)
 typedef enum _Py_memory_order {
@@ -391,13 +391,13 @@ typedef struct _Py_atomic_int {
 #define _Py_atomic_store_64bit(ATOMIC_VAL, NEW_VAL, ORDER) \
     switch (ORDER) { \
     case _Py_memory_order_acquire: \
-      _InterlockedExchange64_acq((__int64 volatile*)&((ATOMIC_VAL)->_value), (__int64)NEW_VAL); \
+      _InterlockedExchange64_acq((__int64 volatile*)ATOMIC_VAL, (__int64)NEW_VAL); \
       break; \
     case _Py_memory_order_release: \
-      _InterlockedExchange64_rel((__int64 volatile*)&((ATOMIC_VAL)->_value), (__int64)NEW_VAL); \
+      _InterlockedExchange64_rel((__int64 volatile*)ATOMIC_VAL, (__int64)NEW_VAL); \
       break; \
     default: \
-      _InterlockedExchange64((__int64 volatile*)&((ATOMIC_VAL)->_value), (__int64)NEW_VAL); \
+      _InterlockedExchange64((__int64 volatile*)ATOMIC_VAL, (__int64)NEW_VAL); \
       break; \
   }
 #else
@@ -407,13 +407,13 @@ typedef struct _Py_atomic_int {
 #define _Py_atomic_store_32bit(ATOMIC_VAL, NEW_VAL, ORDER) \
   switch (ORDER) { \
   case _Py_memory_order_acquire: \
-    _InterlockedExchange_acq((volatile long*)&((ATOMIC_VAL)->_value), (int)NEW_VAL); \
+    _InterlockedExchange_acq((volatile long*)ATOMIC_VAL, (int)NEW_VAL); \
     break; \
   case _Py_memory_order_release: \
-    _InterlockedExchange_rel((volatile long*)&((ATOMIC_VAL)->_value), (int)NEW_VAL); \
+    _InterlockedExchange_rel((volatile long*)ATOMIC_VAL, (int)NEW_VAL); \
     break; \
   default: \
-    _InterlockedExchange((volatile long*)&((ATOMIC_VAL)->_value), (int)NEW_VAL); \
+    _InterlockedExchange((volatile long*)ATOMIC_VAL, (int)NEW_VAL); \
     break; \
   }
 
@@ -454,7 +454,7 @@ inline intptr_t _Py_atomic_load_64bit(volatile uintptr_t* value, int order) {
 }
 
 #else
-#define _Py_atomic_load_64bit(ATOMIC_VAL, ORDER) *(ATOMIC_VAL)
+#define _Py_atomic_load_64bit(ATOMIC_VAL, ORDER) *ATOMIC_VAL
 #endif
 
 inline int _Py_atomic_load_32bit(volatile int* value, int order) {
@@ -489,15 +489,15 @@ inline int _Py_atomic_load_32bit(volatile int* value, int order) {
 }
 
 #define _Py_atomic_store_explicit(ATOMIC_VAL, NEW_VAL, ORDER) \
-  if (sizeof((ATOMIC_VAL)->_value) == 8) { \
-    _Py_atomic_store_64bit(&((ATOMIC_VAL)->_value), NEW_VAL, ORDER) } else { \
-    _Py_atomic_store_32bit(&((ATOMIC_VAL)->_value), NEW_VAL, ORDER) }
+  if (sizeof(*ATOMIC_VAL._value) == 8) { \
+    _Py_atomic_store_64bit(ATOMIC_VAL._value, NEW_VAL, ORDER) } else { \
+    _Py_atomic_store_32bit(ATOMIC_VAL._value, NEW_VAL, ORDER) }
 
 #define _Py_atomic_load_explicit(ATOMIC_VAL, ORDER) \
   ( \
-    sizeof((ATOMIC_VAL)->_value) == 8 ? \
-    _Py_atomic_load_64bit(&((ATOMIC_VAL)->_value), ORDER) : \
-    _Py_atomic_load_32bit(&((ATOMIC_VAL)->_value), ORDER) \
+    sizeof(*(ATOMIC_VAL._value)) == 8 ? \
+    _Py_atomic_load_64bit(ATOMIC_VAL._value, ORDER) : \
+    _Py_atomic_load_32bit(ATOMIC_VAL._value, ORDER) \
   )
 #endif
 #else  /* !gcc x86  !_msc_ver */

Include/internal/pycore_ceval.h

@@ -11,12 +11,8 @@ extern "C" {
 #include "pycore_atomic.h"
 #include "pythread.h"
 
-struct _is;  // See PyInterpreterState in cpython/pystate.h.
-
-PyAPI_FUNC(int) _Py_AddPendingCall(struct _is*, unsigned long, int (*)(void *), void *);
-PyAPI_FUNC(int) _Py_MakePendingCalls(struct _is*);
-
 struct _pending_calls {
+    unsigned long main_thread;
     PyThread_type_lock lock;
     /* Request for running pending calls. */
     _Py_atomic_int calls_to_do;
@@ -26,7 +22,6 @@ struct _pending_calls {
     int async_exc;
 #define NPENDINGCALLS 32
     struct {
-        unsigned long thread_id;
         int (*func)(void *);
         void *arg;
     } calls[NPENDINGCALLS];
@@ -34,13 +29,6 @@ struct _pending_calls {
     int last;
 };
 
-struct _ceval_interpreter_state {
-    /* This single variable consolidates all requests to break out of
-       the fast path in the eval loop. */
-    _Py_atomic_int eval_breaker;
-    struct _pending_calls pending;
-};
-
 #include "pycore_gil.h"
 
 struct _ceval_runtime_state {
@@ -51,8 +39,12 @@ struct _ceval_runtime_state {
        c_tracefunc.  This speeds up the if statement in
        PyEval_EvalFrameEx() after fast_next_opcode. */
     int tracing_possible;
+    /* This single variable consolidates all requests to break out of
+       the fast path in the eval loop. */
+    _Py_atomic_int eval_breaker;
     /* Request for dropping the GIL */
     _Py_atomic_int gil_drop_request;
+    struct _pending_calls pending;
     /* Request for checking signals. */
     _Py_atomic_int signals_pending;
     struct _gil_runtime_state gil;

Include/internal/pycore_pystate.h

@@ -11,7 +11,6 @@ extern "C" {
 #include "pystate.h"
 #include "pythread.h"
 
-#include "pycore_atomic.h"
 #include "pycore_ceval.h"
 #include "pycore_pathconfig.h"
 #include "pycore_pymem.h"
@@ -30,11 +29,8 @@ struct _is {
 
     int64_t id;
     int64_t id_refcount;
-    int requires_idref;
     PyThread_type_lock id_mutex;
 
-    int finalizing;
-
     PyObject *modules;
     PyObject *modules_by_index;
     PyObject *sysdict;
@@ -82,8 +78,6 @@ struct _is {
     PyObject *pyexitmodule;
 
     uint64_t tstate_next_unique_id;
-
-    struct _ceval_interpreter_state ceval;
 };
 
 PyAPI_FUNC(struct _is*) _PyInterpreterState_LookUpID(PY_INT64_T);
@@ -93,12 +87,66 @@ PyAPI_FUNC(void) _PyInterpreterState_IDIncref(struct _is *);
 PyAPI_FUNC(void) _PyInterpreterState_IDDecref(struct _is *);
 
 
+/* cross-interpreter data */
+
+struct _xid;
+
+// _PyCrossInterpreterData is similar to Py_buffer as an effectively
+// opaque struct that holds data outside the object machinery.  This
+// is necessary to pass safely between interpreters in the same process.
+typedef struct _xid {
+    // data is the cross-interpreter-safe derivation of a Python object
+    // (see _PyObject_GetCrossInterpreterData).  It will be NULL if the
+    // new_object func (below) encodes the data.
+    void *data;
+    // obj is the Python object from which the data was derived.  This
+    // is non-NULL only if the data remains bound to the object in some
+    // way, such that the object must be "released" (via a decref) when
+    // the data is released.  In that case the code that sets the field,
+    // likely a registered "crossinterpdatafunc", is responsible for
+    // ensuring it owns the reference (i.e. incref).
+    PyObject *obj;
+    // interp is the ID of the owning interpreter of the original
+    // object.  It corresponds to the active interpreter when
+    // _PyObject_GetCrossInterpreterData() was called.  This should only
+    // be set by the cross-interpreter machinery.
+    //
+    // We use the ID rather than the PyInterpreterState to avoid issues
+    // with deleted interpreters.
+    int64_t interp;
+    // new_object is a function that returns a new object in the current
+    // interpreter given the data.  The resulting object (a new
+    // reference) will be equivalent to the original object.  This field
+    // is required.
+    PyObject *(*new_object)(struct _xid *);
+    // free is called when the data is released.  If it is NULL then
+    // nothing will be done to free the data.  For some types this is
+    // okay (e.g. bytes) and for those types this field should be set
+    // to NULL.  However, for most the data was allocated just for
+    // cross-interpreter use, so it must be freed when
+    // _PyCrossInterpreterData_Release is called or the memory will
+    // leak.  In that case, at the very least this field should be set
+    // to PyMem_RawFree (the default if not explicitly set to NULL).
+    // The call will happen with the original interpreter activated.
+    void (*free)(void *);
+} _PyCrossInterpreterData;
+
+typedef int (*crossinterpdatafunc)(PyObject *, _PyCrossInterpreterData *);
+PyAPI_FUNC(int) _PyObject_CheckCrossInterpreterData(PyObject *);
+
+PyAPI_FUNC(int) _PyObject_GetCrossInterpreterData(PyObject *, _PyCrossInterpreterData *);
+PyAPI_FUNC(PyObject *) _PyCrossInterpreterData_NewObject(_PyCrossInterpreterData *);
+PyAPI_FUNC(void) _PyCrossInterpreterData_Release(_PyCrossInterpreterData *);
+
 /* cross-interpreter data registry */
 
 /* For now we use a global registry of shareable classes.  An
    alternative would be to add a tp_* slot for a class's
    crossinterpdatafunc. It would be simpler and more efficient. */
 
+PyAPI_FUNC(int) _PyCrossInterpreterData_Register_Class(PyTypeObject *, crossinterpdatafunc);
+PyAPI_FUNC(crossinterpdatafunc) _PyCrossInterpreterData_Lookup(PyObject *);
+
 struct _xidregitem;
 
 struct _xidregitem {
@@ -159,8 +207,6 @@ typedef struct pyruntimestate {
         struct _xidregitem *head;
     } xidregistry;
 
-    unsigned long main_thread;
-
 #define NEXITFUNCS 32
     void (*exitfuncs[NEXITFUNCS])(void);
     int nexitfuncs;

Include/interpreteridobject.h

-#ifndef Py_INTERPRETERIDOBJECT_H
-#define Py_INTERPRETERIDOBJECT_H
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#ifndef Py_LIMITED_API
-#  define Py_CPYTHON_INTERPRETERIDOBJECT_H
-#  include  "cpython/interpreteridobject.h"
-#  undef Py_CPYTHON_INTERPRETERIDOBJECT_H
-#endif
-
-#ifdef __cplusplus
-}
-#endif
-#endif /* !Py_INTERPRETERIDOBJECT_H */

Makefile.pre.in

@@ -391,7 +391,6 @@ OBJECT_OBJS=	\
 		Objects/floatobject.o \
 		Objects/frameobject.o \
 		Objects/funcobject.o \
-		Objects/interpreteridobject.o \
 		Objects/iterobject.o \
 		Objects/listobject.o \
 		Objects/longobject.o \
@@ -978,7 +977,6 @@ PYTHON_HEADERS= \
 		$(srcdir)/Include/funcobject.h \
 		$(srcdir)/Include/genobject.h \
 		$(srcdir)/Include/import.h \
-		$(srcdir)/Include/interpreteridobject.h \
 		$(srcdir)/Include/intrcheck.h \
 		$(srcdir)/Include/iterobject.h \
 		$(srcdir)/Include/listobject.h \
@@ -1041,7 +1039,6 @@ PYTHON_HEADERS= \
 		$(srcdir)/Include/cpython/abstract.h \
 		$(srcdir)/Include/cpython/coreconfig.h \
 		$(srcdir)/Include/cpython/dictobject.h \
-		$(srcdir)/Include/cpython/interpreteridobject.h \
 		$(srcdir)/Include/cpython/object.h \
 		$(srcdir)/Include/cpython/objimpl.h \
 		$(srcdir)/Include/cpython/pyerrors.h \

Modules/_testcapimodule.c

@@ -2445,7 +2445,6 @@ pending_threadfunc(PyObject *self, PyObject *arg)
     Py_INCREF(callable);
 
     Py_BEGIN_ALLOW_THREADS
-    /* XXX Use the internal _Py_AddPendingCall(). */
     r = Py_AddPendingCall(&_pending_callback, callable);
     Py_END_ALLOW_THREADS
 

Modules/signalmodule.c

@@ -19,7 +19,6 @@
 #include <process.h>
 #endif
 #endif
-#include "internal/pycore_pystate.h"
 
 #ifdef HAVE_SIGNAL_H
 #include <signal.h>
@@ -296,10 +295,8 @@ trip_signal(int sig_num)
                 {
                     /* Py_AddPendingCall() isn't signal-safe, but we
                        still use it for this exceptional case. */
-                    _Py_AddPendingCall(_PyRuntime.interpreters.main,
-                                       main_thread,
-                                       report_wakeup_send_error,
-                                       (void *)(intptr_t) last_error);
+                    Py_AddPendingCall(report_wakeup_send_error,
+                                      (void *)(intptr_t) last_error);
                 }
             }
         }
@@ -316,10 +313,8 @@ trip_signal(int sig_num)
                 {
                     /* Py_AddPendingCall() isn't signal-safe, but we
                        still use it for this exceptional case. */
-                    _Py_AddPendingCall(_PyRuntime.interpreters.main,
-                                       main_thread,
-                                       report_wakeup_write_error,
-                                       (void *)(intptr_t)errno);
+                    Py_AddPendingCall(report_wakeup_write_error,
+                                      (void *)(intptr_t)errno);
                 }
             }
         }

Objects/interpreteridobject.c

-/* InterpreterID object */
-
-#include "Python.h"
-#include "internal/pycore_pystate.h"
-#include "interpreteridobject.h"
-
-
-int64_t
-_Py_CoerceID(PyObject *orig)
-{
-    PyObject *pyid = PyNumber_Long(orig);
-    if (pyid == NULL) {
-        if (PyErr_ExceptionMatches(PyExc_TypeError)) {
-            PyErr_Format(PyExc_TypeError,
-                         "'id' must be a non-negative int, got %R", orig);
-        }
-        else {
-            PyErr_Format(PyExc_ValueError,
-                         "'id' must be a non-negative int, got %R", orig);
-        }
-        return -1;
-    }
-    int64_t id = PyLong_AsLongLong(pyid);
-    Py_DECREF(pyid);
-    if (id == -1 && PyErr_Occurred() != NULL) {
-        if (!PyErr_ExceptionMatches(PyExc_OverflowError)) {
-            PyErr_Format(PyExc_ValueError,
-                         "'id' must be a non-negative int, got %R", orig);
-        }
-        return -1;
-    }
-    if (id < 0) {
-        PyErr_Format(PyExc_ValueError,
-                     "'id' must be a non-negative int, got %R", orig);
-        return -1;
-    }
-    return id;
-}
-
-typedef struct interpid {
-    PyObject_HEAD
-    int64_t id;
-} interpid;
-
-static interpid *
-newinterpid(PyTypeObject *cls, int64_t id, int force)
-{
-    PyInterpreterState *interp = _PyInterpreterState_LookUpID(id);
-    if (interp == NULL) {
-        if (force) {
-            PyErr_Clear();
-        }
-        else {
-            return NULL;
-        }
-    }
-
-    interpid *self = PyObject_New(interpid, cls);
-    if (self == NULL) {
-        return NULL;
-    }
-    self->id = id;
-
-    if (interp != NULL) {
-        _PyInterpreterState_IDIncref(interp);
-    }
-    return self;
-}
-
-static PyObject *
-interpid_new(PyTypeObject *cls, PyObject *args, PyObject *kwds)
-{
-    static char *kwlist[] = {"id", "force", NULL};
-    PyObject *idobj;
-    int force = 0;
-    if (!PyArg_ParseTupleAndKeywords(args, kwds,
-                                     "O|$p:InterpreterID.__init__", kwlist,
-                                     &idobj, &force)) {
-        return NULL;
-    }
-
-    // Coerce and check the ID.
-    int64_t id;
-    if (PyObject_TypeCheck(idobj, &_PyInterpreterID_Type)) {
-        id = ((interpid *)idobj)->id;
-    }
-    else {
-        id = _Py_CoerceID(idobj);
-        if (id < 0) {
-            return NULL;
-        }
-    }
-
-    return (PyObject *)newinterpid(cls, id, force);
-}
-
-static void
-interpid_dealloc(PyObject *v)
-{
-    int64_t id = ((interpid *)v)->id;
-    PyInterpreterState *interp = _PyInterpreterState_LookUpID(id);
-    if (interp != NULL) {
-        _PyInterpreterState_IDDecref(interp);
-    }
-    else {
-        // already deleted
-        PyErr_Clear();
-    }
-    Py_TYPE(v)->tp_free(v);
-}
-
-static PyObject *
-interpid_repr(PyObject *self)
-{
-    PyTypeObject *type = Py_TYPE(self);
-    const char *name = _PyType_Name(type);
-    interpid *id = (interpid *)self;
-    return PyUnicode_FromFormat("%s(%" PRId64 ")", name, id->id);
-}
-
-static PyObject *
-interpid_str(PyObject *self)
-{
-    interpid *id = (interpid *)self;
-    return PyUnicode_FromFormat("%" PRId64 "", id->id);
-}
-
-static PyObject *
-interpid_int(PyObject *self)
-{
-    interpid *id = (interpid *)self;
-    return PyLong_FromLongLong(id->id);
-}
-
-static PyNumberMethods interpid_as_number = {
-     0,                       /* nb_add */
-     0,                       /* nb_subtract */
-     0,                       /* nb_multiply */
-     0,                       /* nb_remainder */
-     0,                       /* nb_divmod */
-     0,                       /* nb_power */
-     0,                       /* nb_negative */
-     0,                       /* nb_positive */
-     0,                       /* nb_absolute */
-     0,                       /* nb_bool */
-     0,                       /* nb_invert */
-     0,                       /* nb_lshift */
-     0,                       /* nb_rshift */
-     0,                       /* nb_and */
-     0,                       /* nb_xor */
-     0,                       /* nb_or */
-     (unaryfunc)interpid_int, /* nb_int */
-     0,                       /* nb_reserved */
-     0,                       /* nb_float */
-
-     0,                       /* nb_inplace_add */
-     0,                       /* nb_inplace_subtract */
-     0,                       /* nb_inplace_multiply */
-     0,                       /* nb_inplace_remainder */
-     0,                       /* nb_inplace_power */
-     0,                       /* nb_inplace_lshift */
-     0,                       /* nb_inplace_rshift */
-     0,                       /* nb_inplace_and */
-     0,                       /* nb_inplace_xor */
-     0,                       /* nb_inplace_or */
-
-     0,                       /* nb_floor_divide */
-     0,                       /* nb_true_divide */
-     0,                       /* nb_inplace_floor_divide */
-     0,                       /* nb_inplace_true_divide */
-
-     (unaryfunc)interpid_int, /* nb_index */
-};
-
-static Py_hash_t
-interpid_hash(PyObject *self)
-{
-    interpid *id = (interpid *)self;
-    PyObject *obj = PyLong_FromLongLong(id->id);
-    if (obj == NULL) {
-        return -1;
-    }
-    Py_hash_t hash = PyObject_Hash(obj);
-    Py_DECREF(obj);
-    return hash;
-}
-
-static PyObject *
-interpid_richcompare(PyObject *self, PyObject *other, int op)
-{
-    if (op != Py_EQ && op != Py_NE) {
-        Py_RETURN_NOTIMPLEMENTED;
-    }
-
-    if (!PyObject_TypeCheck(self, &_PyInterpreterID_Type)) {
-        Py_RETURN_NOTIMPLEMENTED;
-    }
-
-    interpid *id = (interpid *)self;
-    int equal;
-    if (PyObject_TypeCheck(other, &_PyInterpreterID_Type)) {
-        interpid *otherid = (interpid *)other;
-        equal = (id->id == otherid->id);
-    }
-    else {
-        other = PyNumber_Long(other);
-        if (other == NULL) {
-            PyErr_Clear();
-            Py_RETURN_NOTIMPLEMENTED;
-        }
-        int64_t otherid = PyLong_AsLongLong(other);
-        Py_DECREF(other);
-        if (otherid == -1 && PyErr_Occurred() != NULL) {
-            return NULL;
-        }
-        if (otherid < 0) {
-            equal = 0;
-        }
-        else {
-            equal = (id->id == otherid);
-        }
-    }
-
-    if ((op == Py_EQ && equal) || (op == Py_NE && !equal)) {
-        Py_RETURN_TRUE;
-    }
-    Py_RETURN_FALSE;
-}
-
-PyDoc_STRVAR(interpid_doc,
-"A interpreter ID identifies a interpreter and may be used as an int.");
-
-PyTypeObject _PyInterpreterID_Type = {
-    PyVarObject_HEAD_INIT(&PyType_Type, 0)
-    "InterpreterID",   /* tp_name */
-    sizeof(interpid),               /* tp_basicsize */
-    0,                              /* tp_itemsize */
-    (destructor)interpid_dealloc,   /* tp_dealloc */
-    0,                              /* tp_print */
-    0,                              /* tp_getattr */
-    0,                              /* tp_setattr */
-    0,                              /* tp_as_async */
-    (reprfunc)interpid_repr,        /* tp_repr */
-    &interpid_as_number,            /* tp_as_number */
-    0,                              /* tp_as_sequence */
-    0,                              /* tp_as_mapping */
-    interpid_hash,                  /* tp_hash */
-    0,                              /* tp_call */
-    (reprfunc)interpid_str,         /* tp_str */
-    0,                              /* tp_getattro */
-    0,                              /* tp_setattro */
-    0,                              /* tp_as_buffer */
-    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
-        Py_TPFLAGS_LONG_SUBCLASS,   /* tp_flags */
-    interpid_doc,                   /* tp_doc */
-    0,                              /* tp_traverse */
-    0,                              /* tp_clear */
-    interpid_richcompare,           /* tp_richcompare */
-    0,                              /* tp_weaklistoffset */
-    0,                              /* tp_iter */
-    0,                              /* tp_iternext */
-    0,                              /* tp_methods */
-    0,                              /* tp_members */
-    0,                              /* tp_getset */
-    &PyLong_Type,                   /* tp_base */
-    0,                              /* tp_dict */
-    0,                              /* tp_descr_get */
-    0,                              /* tp_descr_set */
-    0,                              /* tp_dictoffset */
-    0,                              /* tp_init */
-    0,                              /* tp_alloc */
-    interpid_new,                   /* tp_new */
-};
-
-PyObject *_PyInterpreterID_New(int64_t id)
-{
-    return (PyObject *)newinterpid(&_PyInterpreterID_Type, id, 0);
-}
-
-PyObject *
-_PyInterpreterState_GetIDObject(PyInterpreterState *interp)
-{
-    if (_PyInterpreterState_IDInitref(interp) != 0) {
-        return NULL;
-    };
-    PY_INT64_T id = PyInterpreterState_GetID(interp);
-    if (id < 0) {
-        return NULL;
-    }
-    return (PyObject *)newinterpid(&_PyInterpreterID_Type, id, 0);
-}
-
-PyInterpreterState *
-_PyInterpreterID_LookUp(PyObject *requested_id)
-{
-    int64_t id;
-    if (PyObject_TypeCheck(requested_id, &_PyInterpreterID_Type)) {
-        id = ((interpid *)requested_id)->id;
-    }
-    else {
-        id = PyLong_AsLongLong(requested_id);
-        if (id == -1 && PyErr_Occurred() != NULL) {
-            return NULL;
-        }
-        assert(id <= INT64_MAX);
-    }
-    return _PyInterpreterState_LookUpID(id);
-}

Objects/object.c

@@ -5,7 +5,6 @@
 #include "pycore_pystate.h"
 #include "pycore_context.h"
 #include "frameobject.h"
-#include "interpreteridobject.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -1807,7 +1806,6 @@ _PyTypes_Init(void)
     INIT_TYPE(&PySeqIter_Type, "sequence iterator");
     INIT_TYPE(&PyCoro_Type, "coroutine");
     INIT_TYPE(&_PyCoroWrapper_Type, "coroutine wrapper");
-    INIT_TYPE(&_PyInterpreterID_Type, "interpreter ID");
     return _Py_INIT_OK();
 
 #undef INIT_TYPE

PCbuild/pythoncore.vcxproj

@@ -154,7 +154,6 @@
     <ClInclude Include="..\Include\internal\pycore_pystate.h" />
     <ClInclude Include="..\Include\internal\pycore_tupleobject.h" />
     <ClInclude Include="..\Include\internal\pycore_warnings.h" />
-    <ClInclude Include="..\Include\interpreteridobject.h" />
     <ClInclude Include="..\Include\intrcheck.h" />
     <ClInclude Include="..\Include\iterobject.h" />
     <ClInclude Include="..\Include\listobject.h" />
@@ -351,7 +350,6 @@
     <ClCompile Include="..\Objects\frameobject.c" />
     <ClCompile Include="..\Objects\funcobject.c" />
     <ClCompile Include="..\Objects\genobject.c" />
-    <ClCompile Include="..\Objects\interpreteridobject.c" />
     <ClCompile Include="..\Objects\iterobject.c" />
     <ClCompile Include="..\Objects\listobject.c" />
     <ClCompile Include="..\Objects\longobject.c" />

PCbuild/pythoncore.vcxproj.filters

@@ -483,9 +483,6 @@
     <ClInclude Include="..\Include\namespaceobject.h">
       <Filter>Include</Filter>
     </ClInclude>
-    <ClInclude Include="..\Include\interpreteridobject.h">
-      <Filter>Include</Filter>
-    </ClInclude>
     <ClInclude Include="..\Modules\hashtable.h">
       <Filter>Modules</Filter>
     </ClInclude>
@@ -1046,9 +1043,6 @@
     <ClCompile Include="..\Objects\namespaceobject.c">
       <Filter>Objects</Filter>
     </ClCompile>
-    <ClCompile Include="..\Objects\interpreteridobject.c">
-      <Filter>Objects</Filter>
-    </ClCompile>
     <ClCompile Include="..\Modules\_opcode.c">
       <Filter>Modules</Filter>
     </ClCompile>

Python/ceval_gil.h

@@ -176,7 +176,7 @@ static void drop_gil(PyThreadState *tstate)
                     &_PyRuntime.ceval.gil.last_holder)
             ) == tstate)
         {
-        RESET_GIL_DROP_REQUEST(tstate->interp);
+        RESET_GIL_DROP_REQUEST();
             /* NOTE: if COND_WAIT does not atomically start waiting when
                releasing the mutex, another thread can run through, take
                the GIL and drop it again, and reset the condition
@@ -213,7 +213,7 @@ static void take_gil(PyThreadState *tstate)
         if (timed_out &&
             _Py_atomic_load_relaxed(&_PyRuntime.ceval.gil.locked) &&
             _PyRuntime.ceval.gil.switch_number == saved_switchnum) {
-            SET_GIL_DROP_REQUEST(tstate->interp);
+            SET_GIL_DROP_REQUEST();
         }
     }
 _ready:
@@ -239,10 +239,10 @@ _ready:
     MUTEX_UNLOCK(_PyRuntime.ceval.gil.switch_mutex);
 #endif
     if (_Py_atomic_load_relaxed(&_PyRuntime.ceval.gil_drop_request)) {
-        RESET_GIL_DROP_REQUEST(tstate->interp);
+        RESET_GIL_DROP_REQUEST();
     }
     if (tstate->async_exc != NULL) {
-        _PyEval_SignalAsyncExc(tstate->interp);
+        _PyEval_SignalAsyncExc();
     }
 
     MUTEX_UNLOCK(_PyRuntime.ceval.gil.mutex);

Python/pylifecycle.c

@@ -1460,32 +1460,8 @@ Py_EndInterpreter(PyThreadState *tstate)
     if (tstate->frame != NULL)
         Py_FatalError("Py_EndInterpreter: thread still has a frame");
 
-    // Mark as finalizing.
-    if (interp->ceval.pending.lock != NULL) {
-        PyThread_acquire_lock(interp->ceval.pending.lock, 1);
-    }
-    interp->finalizing = 1;
-    if (interp->ceval.pending.lock != NULL) {
-        PyThread_release_lock(interp->ceval.pending.lock);
-    }
-
-    // Wrap up existing threads.
     wait_for_thread_shutdown();
 
-    // Make any pending calls.
-    if (_Py_atomic_load_relaxed(
-                &(interp->ceval.pending.calls_to_do)))
-    {
-        // XXX Ensure that the interpreter is running in the current thread?
-        if (_Py_MakePendingCalls(interp) < 0) {
-            PyObject *exc, *val, *tb;
-            PyErr_Fetch(&exc, &val, &tb);
-            PyErr_BadInternalCall();
-            _PyErr_ChainExceptions(exc, val, tb);
-            PyErr_Print();
-        }
-    }
-
     call_py_exitfuncs(interp);
 
     if (tstate != interp->tstate_head || tstate->next != NULL)

Python/pystate.c

@@ -133,19 +133,28 @@ PyInterpreterState_New(void)
         return NULL;
     }
 
-    memset(interp, 0, sizeof(*interp));
     interp->id_refcount = -1;
+    interp->id_mutex = NULL;
+    interp->modules = NULL;
+    interp->modules_by_index = NULL;
+    interp->sysdict = NULL;
+    interp->builtins = NULL;
+    interp->builtins_copy = NULL;
+    interp->tstate_head = NULL;
     interp->check_interval = 100;
-
-    interp->ceval.pending.lock = PyThread_allocate_lock();
-    if (interp->ceval.pending.lock == NULL) {
-        PyErr_SetString(PyExc_RuntimeError,
-                        "failed to create interpreter ceval pending mutex");
-        return NULL;
-    }
+    interp->num_threads = 0;
+    interp->pythread_stacksize = 0;
+    interp->codec_search_path = NULL;
+    interp->codec_search_cache = NULL;
+    interp->codec_error_registry = NULL;
+    interp->codecs_initialized = 0;
+    interp->fscodec_initialized = 0;
     interp->core_config = _PyCoreConfig_INIT;
     interp->config = _PyMainInterpreterConfig_INIT;
+    interp->importlib = NULL;
+    interp->import_func = NULL;
     interp->eval_frame = _PyEval_EvalFrameDefault;
+    interp->co_extra_user_count = 0;
 #ifdef HAVE_DLOPEN
 #if HAVE_DECL_RTLD_NOW
     interp->dlopenflags = RTLD_NOW;
@@ -153,10 +162,13 @@ PyInterpreterState_New(void)
     interp->dlopenflags = RTLD_LAZY;
 #endif
 #endif
-
-    if (_PyRuntime.main_thread == 0) {
-        _PyRuntime.main_thread = PyThread_get_thread_ident();
-    }
+#ifdef HAVE_FORK
+    interp->before_forkers = NULL;
+    interp->after_forkers_parent = NULL;
+    interp->after_forkers_child = NULL;
+#endif
+    interp->pyexitfunc = NULL;
+    interp->pyexitmodule = NULL;
 
     HEAD_LOCK();
     if (_PyRuntime.interpreters.next_id < 0) {
@@ -211,9 +223,6 @@ PyInterpreterState_Clear(PyInterpreterState *interp)
     Py_CLEAR(interp->after_forkers_parent);
     Py_CLEAR(interp->after_forkers_child);
 #endif
-    // XXX Once we have one allocator per interpreter (i.e.
-    // per-interpreter GC) we must ensure that all of the interpreter's
-    // objects have been cleaned up at the point.
 }
 
 
@@ -254,9 +263,6 @@ PyInterpreterState_Delete(PyInterpreterState *interp)
     if (interp->id_mutex != NULL) {
         PyThread_free_lock(interp->id_mutex);
     }
-    if (interp->ceval.pending.lock != NULL) {
-        PyThread_free_lock(interp->ceval.pending.lock);
-    }
     PyMem_RawFree(interp);
 }
 
@@ -328,37 +334,26 @@ PyInterpreterState_GetID(PyInterpreterState *interp)
 }
 
 
-static PyInterpreterState *
-interp_look_up_id(PY_INT64_T requested_id)
+PyInterpreterState *
+_PyInterpreterState_LookUpID(PY_INT64_T requested_id)
 {
+    if (requested_id < 0)
+        goto error;
+
     PyInterpreterState *interp = PyInterpreterState_Head();
     while (interp != NULL) {
         PY_INT64_T id = PyInterpreterState_GetID(interp);
-        if (id < 0) {
+        if (id < 0)
             return NULL;
-        }
-        if (requested_id == id) {
+        if (requested_id == id)
             return interp;
-        }
         interp = PyInterpreterState_Next(interp);
     }
-    return NULL;
-}
 
-PyInterpreterState *
-_PyInterpreterState_LookUpID(PY_INT64_T requested_id)
-{
-    PyInterpreterState *interp = NULL;
-    if (requested_id >= 0) {
-        HEAD_UNLOCK();
-        interp = interp_look_up_id(requested_id);
-        HEAD_UNLOCK();
-    }
-    if (interp == NULL && !PyErr_Occurred()) {
-        PyErr_Format(PyExc_RuntimeError,
-                     "unrecognized interpreter ID %lld", requested_id);
-    }
-    return interp;
+error:
+    PyErr_Format(PyExc_RuntimeError,
+                 "unrecognized interpreter ID %lld", requested_id);
+    return NULL;
 }
 
 
@@ -403,7 +398,7 @@ _PyInterpreterState_IDDecref(PyInterpreterState *interp)
     int64_t refcount = interp->id_refcount;
     PyThread_release_lock(interp->id_mutex);
 
-    if (refcount == 0 && interp->requires_idref) {
+    if (refcount == 0) {
         // XXX Using the "head" thread isn't strictly correct.
         PyThreadState *tstate = PyInterpreterState_ThreadHead(interp);
         // XXX Possible GILState issues?
@@ -413,18 +408,6 @@ _PyInterpreterState_IDDecref(PyInterpreterState *interp)
     }
 }
 
-int
-_PyInterpreterState_RequiresIDRef(PyInterpreterState *interp)
-{
-    return interp->requires_idref;
-}
-
-void
-_PyInterpreterState_RequireIDRef(PyInterpreterState *interp, int required)
-{
-    interp->requires_idref = required ? 1 : 0;
-}
-
 _PyCoreConfig *
 _PyInterpreterState_GetCoreConfig(PyInterpreterState *interp)
 {
@@ -437,16 +420,6 @@ _PyInterpreterState_GetMainConfig(PyInterpreterState *interp)
     return &interp->config;
 }
 
-PyObject *
-_PyInterpreterState_GetMainModule(PyInterpreterState *interp)
-{
-    if (interp->modules == NULL) {
-        PyErr_SetString(PyExc_RuntimeError, "interpreter not initialized");
-        return NULL;
-    }
-    return PyMapping_GetItemString(interp->modules, "__main__");
-}
-
 /* Default implementation for _PyThreadState_GetFrame */
 static struct _frame *
 threadstate_getframe(PyThreadState *self)
@@ -899,7 +872,7 @@ PyThreadState_SetAsyncExc(unsigned long id, PyObject *exc)
             p->async_exc = exc;
             HEAD_UNLOCK();
             Py_XDECREF(old_exc);
-            _PyEval_SignalAsyncExc(interp);
+            _PyEval_SignalAsyncExc();
             return 1;
         }
     }
@@ -1313,7 +1286,7 @@ _PyObject_GetCrossInterpreterData(PyObject *obj, _PyCrossInterpreterData *data)
     return 0;
 }
 
-static int
+static void
 _release_xidata(void *arg)
 {
     _PyCrossInterpreterData *data = (_PyCrossInterpreterData *)arg;
@@ -1321,8 +1294,30 @@ _release_xidata(void *arg)
         data->free(data->data);
     }
     Py_XDECREF(data->obj);
-    PyMem_Free(data);
-    return 0;
+}
+
+static void
+_call_in_interpreter(PyInterpreterState *interp,
+                     void (*func)(void *), void *arg)
+{
+    /* We would use Py_AddPendingCall() if it weren't specific to the
+     * main interpreter (see bpo-33608).  In the meantime we take a
+     * naive approach.
+     */
+    PyThreadState *save_tstate = NULL;
+    if (interp != _PyInterpreterState_Get()) {
+        // XXX Using the "head" thread isn't strictly correct.
+        PyThreadState *tstate = PyInterpreterState_ThreadHead(interp);
+        // XXX Possible GILState issues?
+        save_tstate = PyThreadState_Swap(tstate);
+    }
+
+    func(arg);
+
+    // Switch back.
+    if (save_tstate != NULL) {
+        PyThreadState_Swap(save_tstate);
+    }
 }
 
 void
@@ -1333,7 +1328,7 @@ _PyCrossInterpreterData_Release(_PyCrossInterpreterData *data)
         return;
     }
 
-    // Get the original interpreter.
+    // Switch to the original interpreter.
     PyInterpreterState *interp = _PyInterpreterState_LookUpID(data->interp);
     if (interp == NULL) {
         // The intepreter was already destroyed.
@@ -1342,24 +1337,9 @@ _PyCrossInterpreterData_Release(_PyCrossInterpreterData *data)
         }
         return;
     }
-    // XXX There's an ever-so-slight race here...
-    if (interp->finalizing) {
-        // XXX Someone leaked some memory...
-        return;
-    }
 
     // "Release" the data and/or the object.
-    _PyCrossInterpreterData *copied = PyMem_Malloc(sizeof(_PyCrossInterpreterData));
-    if (copied == NULL) {
-        PyErr_SetString(PyExc_MemoryError,
-                        "Not enough memory to preserve cross-interpreter data");
-        PyErr_Print();
-        return;
-    }
-    memcpy(copied, data, sizeof(_PyCrossInterpreterData));
-    if (_Py_AddPendingCall(interp, 0, _release_xidata, copied) != 0) {
-        // XXX Queue full or couldn't get lock.  Try again somehow?
-    }
+    _call_in_interpreter(interp, _release_xidata, data);
 }
 
 PyObject *
@@ -1392,7 +1372,7 @@ _register_xidata(PyTypeObject *cls, crossinterpdatafunc getdata)
 static void _register_builtins_for_crossinterpreter_data(void);
 
 int
-_PyCrossInterpreterData_RegisterClass(PyTypeObject *cls,
+_PyCrossInterpreterData_Register_Class(PyTypeObject *cls,
                                        crossinterpdatafunc getdata)
 {
     if (!PyType_Check(cls)) {

setup.py

@@ -784,7 +784,9 @@ class PyBuildExt(build_ext):
         self.add(Extension('syslog', ['syslogmodule.c']))
 
         # Python interface to subinterpreter C-API.
-        self.add(Extension('_xxsubinterpreters', ['_xxsubinterpretersmodule.c']))
+        self.add(Extension('_xxsubinterpreters',
+                           ['_xxsubinterpretersmodule.c'],
+                           define_macros=[('Py_BUILD_CORE', '')]))
 
         #
         # Here ends the simple stuff.  From here on, modules need certain