Update Python from 3.11.8 to 3.12.2

1 files changed, 1089 insertions, 0 deletions

diff --git a/contrib/tools/python3/src/Python/ceval_gil.c b/contrib/tools/python3/src/Python/ceval_gil.c
new file mode 100644
index 0000000000..c1ab588356
--- /dev/null
+++ b/contrib/tools/python3/src/Python/ceval_gil.c
@@ -0,0 +1,1089 @@
+
+#include "Python.h"
+#include "pycore_atomic.h"        // _Py_atomic_int
+#include "pycore_ceval.h"         // _PyEval_SignalReceived()
+#include "pycore_pyerrors.h"      // _PyErr_GetRaisedException()
+#include "pycore_pylifecycle.h"   // _PyErr_Print()
+#include "pycore_initconfig.h"    // _PyStatus_OK()
+#include "pycore_interp.h"        // _Py_RunGC()
+#include "pycore_pymem.h"         // _PyMem_IsPtrFreed()
+
+/*
+   Notes about the implementation:
+
+   - The GIL is just a boolean variable (locked) whose access is protected
+     by a mutex (gil_mutex), and whose changes are signalled by a condition
+     variable (gil_cond). gil_mutex is taken for short periods of time,
+     and therefore mostly uncontended.
+
+   - In the GIL-holding thread, the main loop (PyEval_EvalFrameEx) must be
+     able to release the GIL on demand by another thread. A volatile boolean
+     variable (gil_drop_request) is used for that purpose, which is checked
+     at every turn of the eval loop. That variable is set after a wait of
+     `interval` microseconds on `gil_cond` has timed out.
+
+      [Actually, another volatile boolean variable (eval_breaker) is used
+       which ORs several conditions into one. Volatile booleans are
+       sufficient as inter-thread signalling means since Python is run
+       on cache-coherent architectures only.]
+
+   - A thread wanting to take the GIL will first let pass a given amount of
+     time (`interval` microseconds) before setting gil_drop_request. This
+     encourages a defined switching period, but doesn't enforce it since
+     opcodes can take an arbitrary time to execute.
+
+     The `interval` value is available for the user to read and modify
+     using the Python API `sys.{get,set}switchinterval()`.
+
+   - When a thread releases the GIL and gil_drop_request is set, that thread
+     ensures that another GIL-awaiting thread gets scheduled.
+     It does so by waiting on a condition variable (switch_cond) until
+     the value of last_holder is changed to something else than its
+     own thread state pointer, indicating that another thread was able to
+     take the GIL.
+
+     This is meant to prohibit the latency-adverse behaviour on multi-core
+     machines where one thread would speculatively release the GIL, but still
+     run and end up being the first to re-acquire it, making the "timeslices"
+     much longer than expected.
+     (Note: this mechanism is enabled with FORCE_SWITCHING above)
+*/
+
+// GH-89279: Force inlining by using a macro.
+#if defined(_MSC_VER) && SIZEOF_INT == 4
+#define _Py_atomic_load_relaxed_int32(ATOMIC_VAL) (assert(sizeof((ATOMIC_VAL)->_value) == 4), *((volatile int*)&((ATOMIC_VAL)->_value)))
+#else
+#define _Py_atomic_load_relaxed_int32(ATOMIC_VAL) _Py_atomic_load_relaxed(ATOMIC_VAL)
+#endif
+
+/* This can set eval_breaker to 0 even though gil_drop_request became
+   1.  We believe this is all right because the eval loop will release
+   the GIL eventually anyway. */
+static inline void
+COMPUTE_EVAL_BREAKER(PyInterpreterState *interp,
+                     struct _ceval_runtime_state *ceval,
+                     struct _ceval_state *ceval2)
+{
+    _Py_atomic_store_relaxed(&ceval2->eval_breaker,
+        _Py_atomic_load_relaxed_int32(&ceval2->gil_drop_request)
+        | (_Py_atomic_load_relaxed_int32(&ceval->signals_pending)
+           && _Py_ThreadCanHandleSignals(interp))
+        | (_Py_atomic_load_relaxed_int32(&ceval2->pending.calls_to_do))
+        | (_Py_IsMainThread() && _Py_IsMainInterpreter(interp)
+           &&_Py_atomic_load_relaxed_int32(&ceval->pending_mainthread.calls_to_do))
+        | ceval2->pending.async_exc
+        | _Py_atomic_load_relaxed_int32(&ceval2->gc_scheduled));
+}
+
+
+static inline void
+SET_GIL_DROP_REQUEST(PyInterpreterState *interp)
+{
+    struct _ceval_state *ceval2 = &interp->ceval;
+    _Py_atomic_store_relaxed(&ceval2->gil_drop_request, 1);
+    _Py_atomic_store_relaxed(&ceval2->eval_breaker, 1);
+}
+
+
+static inline void
+RESET_GIL_DROP_REQUEST(PyInterpreterState *interp)
+{
+    struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
+    struct _ceval_state *ceval2 = &interp->ceval;
+    _Py_atomic_store_relaxed(&ceval2->gil_drop_request, 0);
+    COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
+}
+
+
+static inline void
+SIGNAL_PENDING_CALLS(struct _pending_calls *pending, PyInterpreterState *interp)
+{
+    struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
+    struct _ceval_state *ceval2 = &interp->ceval;
+    _Py_atomic_store_relaxed(&pending->calls_to_do, 1);
+    COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
+}
+
+
+static inline void
+UNSIGNAL_PENDING_CALLS(PyInterpreterState *interp)
+{
+    struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
+    struct _ceval_state *ceval2 = &interp->ceval;
+    if (_Py_IsMainThread() && _Py_IsMainInterpreter(interp)) {
+        _Py_atomic_store_relaxed(&ceval->pending_mainthread.calls_to_do, 0);
+    }
+    _Py_atomic_store_relaxed(&ceval2->pending.calls_to_do, 0);
+    COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
+}
+
+
+static inline void
+SIGNAL_PENDING_SIGNALS(PyInterpreterState *interp, int force)
+{
+    struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
+    struct _ceval_state *ceval2 = &interp->ceval;
+    _Py_atomic_store_relaxed(&ceval->signals_pending, 1);
+    if (force) {
+        _Py_atomic_store_relaxed(&ceval2->eval_breaker, 1);
+    }
+    else {
+        /* eval_breaker is not set to 1 if thread_can_handle_signals() is false */
+        COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
+    }
+}
+
+
+static inline void
+UNSIGNAL_PENDING_SIGNALS(PyInterpreterState *interp)
+{
+    struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
+    struct _ceval_state *ceval2 = &interp->ceval;
+    _Py_atomic_store_relaxed(&ceval->signals_pending, 0);
+    COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
+}
+
+
+static inline void
+SIGNAL_ASYNC_EXC(PyInterpreterState *interp)
+{
+    struct _ceval_state *ceval2 = &interp->ceval;
+    ceval2->pending.async_exc = 1;
+    _Py_atomic_store_relaxed(&ceval2->eval_breaker, 1);
+}
+
+
+static inline void
+UNSIGNAL_ASYNC_EXC(PyInterpreterState *interp)
+{
+    struct _ceval_runtime_state *ceval = &interp->runtime->ceval;
+    struct _ceval_state *ceval2 = &interp->ceval;
+    ceval2->pending.async_exc = 0;
+    COMPUTE_EVAL_BREAKER(interp, ceval, ceval2);
+}
+
+
+/*
+ * Implementation of the Global Interpreter Lock (GIL).
+ */
+
+#include <stdlib.h>
+#include <errno.h>
+
+#include "pycore_atomic.h"
+
+
+#include "condvar.h"
+
+#define MUTEX_INIT(mut) \
+    if (PyMUTEX_INIT(&(mut))) { \
+        Py_FatalError("PyMUTEX_INIT(" #mut ") failed"); };
+#define MUTEX_FINI(mut) \
+    if (PyMUTEX_FINI(&(mut))) { \
+        Py_FatalError("PyMUTEX_FINI(" #mut ") failed"); };
+#define MUTEX_LOCK(mut) \
+    if (PyMUTEX_LOCK(&(mut))) { \
+        Py_FatalError("PyMUTEX_LOCK(" #mut ") failed"); };
+#define MUTEX_UNLOCK(mut) \
+    if (PyMUTEX_UNLOCK(&(mut))) { \
+        Py_FatalError("PyMUTEX_UNLOCK(" #mut ") failed"); };
+
+#define COND_INIT(cond) \
+    if (PyCOND_INIT(&(cond))) { \
+        Py_FatalError("PyCOND_INIT(" #cond ") failed"); };
+#define COND_FINI(cond) \
+    if (PyCOND_FINI(&(cond))) { \
+        Py_FatalError("PyCOND_FINI(" #cond ") failed"); };
+#define COND_SIGNAL(cond) \
+    if (PyCOND_SIGNAL(&(cond))) { \
+        Py_FatalError("PyCOND_SIGNAL(" #cond ") failed"); };
+#define COND_WAIT(cond, mut) \
+    if (PyCOND_WAIT(&(cond), &(mut))) { \
+        Py_FatalError("PyCOND_WAIT(" #cond ") failed"); };
+#define COND_TIMED_WAIT(cond, mut, microseconds, timeout_result) \
+    { \
+        int r = PyCOND_TIMEDWAIT(&(cond), &(mut), (microseconds)); \
+        if (r < 0) \
+            Py_FatalError("PyCOND_WAIT(" #cond ") failed"); \
+        if (r) /* 1 == timeout, 2 == impl. can't say, so assume timeout */ \
+            timeout_result = 1; \
+        else \
+            timeout_result = 0; \
+    } \
+
+
+#define DEFAULT_INTERVAL 5000
+
+static void _gil_initialize(struct _gil_runtime_state *gil)
+{
+    _Py_atomic_int uninitialized = {-1};
+    gil->locked = uninitialized;
+    gil->interval = DEFAULT_INTERVAL;
+}
+
+static int gil_created(struct _gil_runtime_state *gil)
+{
+    if (gil == NULL) {
+        return 0;
+    }
+    return (_Py_atomic_load_explicit(&gil->locked, _Py_memory_order_acquire) >= 0);
+}
+
+static void create_gil(struct _gil_runtime_state *gil)
+{
+    MUTEX_INIT(gil->mutex);
+#ifdef FORCE_SWITCHING
+    MUTEX_INIT(gil->switch_mutex);
+#endif
+    COND_INIT(gil->cond);
+#ifdef FORCE_SWITCHING
+    COND_INIT(gil->switch_cond);
+#endif
+    _Py_atomic_store_relaxed(&gil->last_holder, 0);
+    _Py_ANNOTATE_RWLOCK_CREATE(&gil->locked);
+    _Py_atomic_store_explicit(&gil->locked, 0, _Py_memory_order_release);
+}
+
+static void destroy_gil(struct _gil_runtime_state *gil)
+{
+    /* some pthread-like implementations tie the mutex to the cond
+     * and must have the cond destroyed first.
+     */
+    COND_FINI(gil->cond);
+    MUTEX_FINI(gil->mutex);
+#ifdef FORCE_SWITCHING
+    COND_FINI(gil->switch_cond);
+    MUTEX_FINI(gil->switch_mutex);
+#endif
+    _Py_atomic_store_explicit(&gil->locked, -1,
+                              _Py_memory_order_release);
+    _Py_ANNOTATE_RWLOCK_DESTROY(&gil->locked);
+}
+
+#ifdef HAVE_FORK
+static void recreate_gil(struct _gil_runtime_state *gil)
+{
+    _Py_ANNOTATE_RWLOCK_DESTROY(&gil->locked);
+    /* XXX should we destroy the old OS resources here? */
+    create_gil(gil);
+}
+#endif
+
+static void
+drop_gil(struct _ceval_state *ceval, PyThreadState *tstate)
+{
+    /* If tstate is NULL, the caller is indicating that we're releasing
+       the GIL for the last time in this thread.  This is particularly
+       relevant when the current thread state is finalizing or its
+       interpreter is finalizing (either may be in an inconsistent
+       state).  In that case the current thread will definitely
+       never try to acquire the GIL again. */
+    // XXX It may be more correct to check tstate->_status.finalizing.
+    // XXX assert(tstate == NULL || !tstate->_status.cleared);
+
+    struct _gil_runtime_state *gil = ceval->gil;
+    if (!_Py_atomic_load_relaxed(&gil->locked)) {
+        Py_FatalError("drop_gil: GIL is not locked");
+    }
+
+    /* tstate is allowed to be NULL (early interpreter init) */
+    if (tstate != NULL) {
+        /* Sub-interpreter support: threads might have been switched
+           under our feet using PyThreadState_Swap(). Fix the GIL last
+           holder variable so that our heuristics work. */
+        _Py_atomic_store_relaxed(&gil->last_holder, (uintptr_t)tstate);
+    }
+
+    MUTEX_LOCK(gil->mutex);
+    _Py_ANNOTATE_RWLOCK_RELEASED(&gil->locked, /*is_write=*/1);
+    _Py_atomic_store_relaxed(&gil->locked, 0);
+    COND_SIGNAL(gil->cond);
+    MUTEX_UNLOCK(gil->mutex);
+
+#ifdef FORCE_SWITCHING
+    /* We check tstate first in case we might be releasing the GIL for
+       the last time in this thread.  In that case there's a possible
+       race with tstate->interp getting deleted after gil->mutex is
+       unlocked and before the following code runs, leading to a crash.
+       We can use (tstate == NULL) to indicate the thread is done with
+       the GIL, and that's the only time we might delete the
+       interpreter, so checking tstate first prevents the crash.
+       See https://github.com/python/cpython/issues/104341. */
+    if (tstate != NULL && _Py_atomic_load_relaxed(&ceval->gil_drop_request)) {
+        MUTEX_LOCK(gil->switch_mutex);
+        /* Not switched yet => wait */
+        if (((PyThreadState*)_Py_atomic_load_relaxed(&gil->last_holder)) == tstate)
+        {
+            assert(_PyThreadState_CheckConsistency(tstate));
+            RESET_GIL_DROP_REQUEST(tstate->interp);
+            /* 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
+               before we even had a chance to wait for it. */
+            COND_WAIT(gil->switch_cond, gil->switch_mutex);
+        }
+        MUTEX_UNLOCK(gil->switch_mutex);
+    }
+#endif
+}
+
+
+/* Take the GIL.
+
+   The function saves errno at entry and restores its value at exit.
+
+   tstate must be non-NULL. */
+static void
+take_gil(PyThreadState *tstate)
+{
+    int err = errno;
+
+    assert(tstate != NULL);
+    /* We shouldn't be using a thread state that isn't viable any more. */
+    // XXX It may be more correct to check tstate->_status.finalizing.
+    // XXX assert(!tstate->_status.cleared);
+
+    if (_PyThreadState_MustExit(tstate)) {
+        /* bpo-39877: If Py_Finalize() has been called and tstate is not the
+           thread which called Py_Finalize(), exit immediately the thread.
+
+           This code path can be reached by a daemon thread after Py_Finalize()
+           completes. In this case, tstate is a dangling pointer: points to
+           PyThreadState freed memory. */
+        PyThread_exit_thread();
+    }
+
+    assert(_PyThreadState_CheckConsistency(tstate));
+    PyInterpreterState *interp = tstate->interp;
+    struct _ceval_state *ceval = &interp->ceval;
+    struct _gil_runtime_state *gil = ceval->gil;
+
+    /* Check that _PyEval_InitThreads() was called to create the lock */
+    assert(gil_created(gil));
+
+    MUTEX_LOCK(gil->mutex);
+
+    if (!_Py_atomic_load_relaxed(&gil->locked)) {
+        goto _ready;
+    }
+
+    int drop_requested = 0;
+    while (_Py_atomic_load_relaxed(&gil->locked)) {
+        unsigned long saved_switchnum = gil->switch_number;
+
+        unsigned long interval = (gil->interval >= 1 ? gil->interval : 1);
+        int timed_out = 0;
+        COND_TIMED_WAIT(gil->cond, gil->mutex, interval, timed_out);
+
+        /* If we timed out and no switch occurred in the meantime, it is time
+           to ask the GIL-holding thread to drop it. */
+        if (timed_out &&
+            _Py_atomic_load_relaxed(&gil->locked) &&
+            gil->switch_number == saved_switchnum)
+        {
+            if (_PyThreadState_MustExit(tstate)) {
+                MUTEX_UNLOCK(gil->mutex);
+                // gh-96387: If the loop requested a drop request in a previous
+                // iteration, reset the request. Otherwise, drop_gil() can
+                // block forever waiting for the thread which exited. Drop
+                // requests made by other threads are also reset: these threads
+                // may have to request again a drop request (iterate one more
+                // time).
+                if (drop_requested) {
+                    RESET_GIL_DROP_REQUEST(interp);
+                }
+                PyThread_exit_thread();
+            }
+            assert(_PyThreadState_CheckConsistency(tstate));
+
+            SET_GIL_DROP_REQUEST(interp);
+            drop_requested = 1;
+        }
+    }
+
+_ready:
+#ifdef FORCE_SWITCHING
+    /* This mutex must be taken before modifying gil->last_holder:
+       see drop_gil(). */
+    MUTEX_LOCK(gil->switch_mutex);
+#endif
+    /* We now hold the GIL */
+    _Py_atomic_store_relaxed(&gil->locked, 1);
+    _Py_ANNOTATE_RWLOCK_ACQUIRED(&gil->locked, /*is_write=*/1);
+
+    if (tstate != (PyThreadState*)_Py_atomic_load_relaxed(&gil->last_holder)) {
+        _Py_atomic_store_relaxed(&gil->last_holder, (uintptr_t)tstate);
+        ++gil->switch_number;
+    }
+
+#ifdef FORCE_SWITCHING
+    COND_SIGNAL(gil->switch_cond);
+    MUTEX_UNLOCK(gil->switch_mutex);
+#endif
+
+    if (_PyThreadState_MustExit(tstate)) {
+        /* bpo-36475: If Py_Finalize() has been called and tstate is not
+           the thread which called Py_Finalize(), exit immediately the
+           thread.
+
+           This code path can be reached by a daemon thread which was waiting
+           in take_gil() while the main thread called
+           wait_for_thread_shutdown() from Py_Finalize(). */
+        MUTEX_UNLOCK(gil->mutex);
+        drop_gil(ceval, tstate);
+        PyThread_exit_thread();
+    }
+    assert(_PyThreadState_CheckConsistency(tstate));
+
+    if (_Py_atomic_load_relaxed(&ceval->gil_drop_request)) {
+        RESET_GIL_DROP_REQUEST(interp);
+    }
+    else {
+        /* bpo-40010: eval_breaker should be recomputed to be set to 1 if there
+           is a pending signal: signal received by another thread which cannot
+           handle signals.
+
+           Note: RESET_GIL_DROP_REQUEST() calls COMPUTE_EVAL_BREAKER(). */
+        COMPUTE_EVAL_BREAKER(interp, &_PyRuntime.ceval, ceval);
+    }
+
+    /* Don't access tstate if the thread must exit */
+    if (tstate->async_exc != NULL) {
+        _PyEval_SignalAsyncExc(tstate->interp);
+    }
+
+    MUTEX_UNLOCK(gil->mutex);
+
+    errno = err;
+}
+
+void _PyEval_SetSwitchInterval(unsigned long microseconds)
+{
+    PyInterpreterState *interp = _PyInterpreterState_Get();
+    struct _gil_runtime_state *gil = interp->ceval.gil;
+    assert(gil != NULL);
+    gil->interval = microseconds;
+}
+
+unsigned long _PyEval_GetSwitchInterval(void)
+{
+    PyInterpreterState *interp = _PyInterpreterState_Get();
+    struct _gil_runtime_state *gil = interp->ceval.gil;
+    assert(gil != NULL);
+    return gil->interval;
+}
+
+
+int
+_PyEval_ThreadsInitialized(void)
+{
+    /* XXX This is only needed for an assert in PyGILState_Ensure(),
+     * which currently does not work with subinterpreters.
+     * Thus we only use the main interpreter. */
+    PyInterpreterState *interp = _PyInterpreterState_Main();
+    if (interp == NULL) {
+        return 0;
+    }
+    struct _gil_runtime_state *gil = interp->ceval.gil;
+    return gil_created(gil);
+}
+
+int
+PyEval_ThreadsInitialized(void)
+{
+    return _PyEval_ThreadsInitialized();
+}
+
+static inline int
+current_thread_holds_gil(struct _gil_runtime_state *gil, PyThreadState *tstate)
+{
+    if (((PyThreadState*)_Py_atomic_load_relaxed(&gil->last_holder)) != tstate) {
+        return 0;
+    }
+    return _Py_atomic_load_relaxed(&gil->locked);
+}
+
+static void
+init_shared_gil(PyInterpreterState *interp, struct _gil_runtime_state *gil)
+{
+    assert(gil_created(gil));
+    interp->ceval.gil = gil;
+    interp->ceval.own_gil = 0;
+}
+
+static void
+init_own_gil(PyInterpreterState *interp, struct _gil_runtime_state *gil)
+{
+    assert(!gil_created(gil));
+    create_gil(gil);
+    assert(gil_created(gil));
+    interp->ceval.gil = gil;
+    interp->ceval.own_gil = 1;
+}
+
+PyStatus
+_PyEval_InitGIL(PyThreadState *tstate, int own_gil)
+{
+    assert(tstate->interp->ceval.gil == NULL);
+    int locked;
+    if (!own_gil) {
+        /* The interpreter will share the main interpreter's instead. */
+        PyInterpreterState *main_interp = _PyInterpreterState_Main();
+        assert(tstate->interp != main_interp);
+        struct _gil_runtime_state *gil = main_interp->ceval.gil;
+        init_shared_gil(tstate->interp, gil);
+        locked = current_thread_holds_gil(gil, tstate);
+    }
+    else {
+        PyThread_init_thread();
+        init_own_gil(tstate->interp, &tstate->interp->_gil);
+        locked = 0;
+    }
+    if (!locked) {
+        take_gil(tstate);
+    }
+
+    return _PyStatus_OK();
+}
+
+void
+_PyEval_FiniGIL(PyInterpreterState *interp)
+{
+    struct _gil_runtime_state *gil = interp->ceval.gil;
+    if (gil == NULL) {
+        /* It was already finalized (or hasn't been initialized yet). */
+        assert(!interp->ceval.own_gil);
+        return;
+    }
+    else if (!interp->ceval.own_gil) {
+#ifdef Py_DEBUG
+        PyInterpreterState *main_interp = _PyInterpreterState_Main();
+        assert(main_interp != NULL && interp != main_interp);
+        assert(interp->ceval.gil == main_interp->ceval.gil);
+#endif
+        interp->ceval.gil = NULL;
+        return;
+    }
+
+    if (!gil_created(gil)) {
+        /* First Py_InitializeFromConfig() call: the GIL doesn't exist
+           yet: do nothing. */
+        return;
+    }
+
+    destroy_gil(gil);
+    assert(!gil_created(gil));
+    interp->ceval.gil = NULL;
+}
+
+void
+PyEval_InitThreads(void)
+{
+    /* Do nothing: kept for backward compatibility */
+}
+
+void
+_PyEval_Fini(void)
+{
+#ifdef Py_STATS
+    _Py_PrintSpecializationStats(1);
+#endif
+}
+void
+PyEval_AcquireLock(void)
+{
+    PyThreadState *tstate = _PyThreadState_GET();
+    _Py_EnsureTstateNotNULL(tstate);
+
+    take_gil(tstate);
+}
+
+void
+PyEval_ReleaseLock(void)
+{
+    PyThreadState *tstate = _PyThreadState_GET();
+    /* This function must succeed when the current thread state is NULL.
+       We therefore avoid PyThreadState_Get() which dumps a fatal error
+       in debug mode. */
+    struct _ceval_state *ceval = &tstate->interp->ceval;
+    drop_gil(ceval, tstate);
+}
+
+void
+_PyEval_AcquireLock(PyThreadState *tstate)
+{
+    _Py_EnsureTstateNotNULL(tstate);
+    take_gil(tstate);
+}
+
+void
+_PyEval_ReleaseLock(PyInterpreterState *interp, PyThreadState *tstate)
+{
+    /* If tstate is NULL then we do not expect the current thread
+       to acquire the GIL ever again. */
+    assert(tstate == NULL || tstate->interp == interp);
+    struct _ceval_state *ceval = &interp->ceval;
+    drop_gil(ceval, tstate);
+}
+
+void
+PyEval_AcquireThread(PyThreadState *tstate)
+{
+    _Py_EnsureTstateNotNULL(tstate);
+
+    take_gil(tstate);
+
+    if (_PyThreadState_SwapNoGIL(tstate) != NULL) {
+        Py_FatalError("non-NULL old thread state");
+    }
+}
+
+void
+PyEval_ReleaseThread(PyThreadState *tstate)
+{
+    assert(_PyThreadState_CheckConsistency(tstate));
+
+    PyThreadState *new_tstate = _PyThreadState_SwapNoGIL(NULL);
+    if (new_tstate != tstate) {
+        Py_FatalError("wrong thread state");
+    }
+    struct _ceval_state *ceval = &tstate->interp->ceval;
+    drop_gil(ceval, tstate);
+}
+
+#ifdef HAVE_FORK
+/* This function is called from PyOS_AfterFork_Child to destroy all threads
+   which are not running in the child process, and clear internal locks
+   which might be held by those threads. */
+PyStatus
+_PyEval_ReInitThreads(PyThreadState *tstate)
+{
+    assert(tstate->interp == _PyInterpreterState_Main());
+
+    struct _gil_runtime_state *gil = tstate->interp->ceval.gil;
+    if (!gil_created(gil)) {
+        return _PyStatus_OK();
+    }
+    recreate_gil(gil);
+
+    take_gil(tstate);
+
+    struct _pending_calls *pending = &tstate->interp->ceval.pending;
+    if (_PyThread_at_fork_reinit(&pending->lock) < 0) {
+        return _PyStatus_ERR("Can't reinitialize pending calls lock");
+    }
+
+    /* Destroy all threads except the current one */
+    _PyThreadState_DeleteExcept(tstate);
+    return _PyStatus_OK();
+}
+#endif
+
+/* This function is used to signal that async exceptions are waiting to be
+   raised. */
+
+void
+_PyEval_SignalAsyncExc(PyInterpreterState *interp)
+{
+    SIGNAL_ASYNC_EXC(interp);
+}
+
+PyThreadState *
+PyEval_SaveThread(void)
+{
+    PyThreadState *tstate = _PyThreadState_SwapNoGIL(NULL);
+    _Py_EnsureTstateNotNULL(tstate);
+
+    struct _ceval_state *ceval = &tstate->interp->ceval;
+    assert(gil_created(ceval->gil));
+    drop_gil(ceval, tstate);
+    return tstate;
+}
+
+void
+PyEval_RestoreThread(PyThreadState *tstate)
+{
+    _Py_EnsureTstateNotNULL(tstate);
+
+    take_gil(tstate);
+
+    _PyThreadState_SwapNoGIL(tstate);
+}
+
+
+/* Mechanism whereby asynchronously executing callbacks (e.g. UNIX
+   signal handlers or Mac I/O completion routines) can schedule calls
+   to a function to be called synchronously.
+   The synchronous function is called with one void* argument.
+   It should return 0 for success or -1 for failure -- failure should
+   be accompanied by an exception.
+
+   If registry succeeds, the registry function returns 0; if it fails
+   (e.g. due to too many pending calls) it returns -1 (without setting
+   an exception condition).
+
+   Note that because registry may occur from within signal handlers,
+   or other asynchronous events, calling malloc() is unsafe!
+
+   Any thread can schedule pending calls, but only the main thread
+   will execute them.
+   There is no facility to schedule calls to a particular thread, but
+   that should be easy to change, should that ever be required.  In
+   that case, the static variables here should go into the python
+   threadstate.
+*/
+
+void
+_PyEval_SignalReceived(PyInterpreterState *interp)
+{
+#ifdef MS_WINDOWS
+    // bpo-42296: On Windows, _PyEval_SignalReceived() is called from a signal
+    // handler which can run in a thread different than the Python thread, in
+    // which case _Py_ThreadCanHandleSignals() is wrong. Ignore
+    // _Py_ThreadCanHandleSignals() and always set eval_breaker to 1.
+    //
+    // The next eval_frame_handle_pending() call will call
+    // _Py_ThreadCanHandleSignals() to recompute eval_breaker.
+    int force = 1;
+#else
+    int force = 0;
+#endif
+    /* bpo-30703: Function called when the C signal handler of Python gets a
+       signal. We cannot queue a callback using _PyEval_AddPendingCall() since
+       that function is not async-signal-safe. */
+    SIGNAL_PENDING_SIGNALS(interp, force);
+}
+
+/* Push one item onto the queue while holding the lock. */
+static int
+_push_pending_call(struct _pending_calls *pending,
+                   int (*func)(void *), void *arg)
+{
+    int i = pending->last;
+    int j = (i + 1) % NPENDINGCALLS;
+    if (j == pending->first) {
+        return -1; /* Queue full */
+    }
+    pending->calls[i].func = func;
+    pending->calls[i].arg = arg;
+    pending->last = j;
+    return 0;
+}
+
+static int
+_next_pending_call(struct _pending_calls *pending,
+                   int (**func)(void *), void **arg)
+{
+    int i = pending->first;
+    if (i == pending->last) {
+        /* Queue empty */
+        assert(pending->calls[i].func == NULL);
+        return -1;
+    }
+    *func = pending->calls[i].func;
+    *arg = pending->calls[i].arg;
+    return i;
+}
+
+/* Pop one item off the queue while holding the lock. */
+static void
+_pop_pending_call(struct _pending_calls *pending,
+                  int (**func)(void *), void **arg)
+{
+    int i = _next_pending_call(pending, func, arg);
+    if (i >= 0) {
+        pending->calls[i] = (struct _pending_call){0};
+        pending->first = (i + 1) % NPENDINGCALLS;
+    }
+}
+
+/* This implementation is thread-safe.  It allows
+   scheduling to be made from any thread, and even from an executing
+   callback.
+ */
+
+int
+_PyEval_AddPendingCall(PyInterpreterState *interp,
+                       int (*func)(void *), void *arg,
+                       int mainthreadonly)
+{
+    assert(!mainthreadonly || _Py_IsMainInterpreter(interp));
+    struct _pending_calls *pending = &interp->ceval.pending;
+    if (mainthreadonly) {
+        /* The main thread only exists in the main interpreter. */
+        assert(_Py_IsMainInterpreter(interp));
+        pending = &_PyRuntime.ceval.pending_mainthread;
+    }
+    /* Ensure that _PyEval_InitState() was called
+       and that _PyEval_FiniState() is not called yet. */
+    assert(pending->lock != NULL);
+
+    PyThread_acquire_lock(pending->lock, WAIT_LOCK);
+    int result = _push_pending_call(pending, func, arg);
+    PyThread_release_lock(pending->lock);
+
+    /* signal main loop */
+    SIGNAL_PENDING_CALLS(pending, interp);
+    return result;
+}
+
+int
+Py_AddPendingCall(int (*func)(void *), void *arg)
+{
+    /* Legacy users of this API will continue to target the main thread
+       (of the main interpreter). */
+    PyInterpreterState *interp = _PyInterpreterState_Main();
+    return _PyEval_AddPendingCall(interp, func, arg, 1);
+}
+
+static int
+handle_signals(PyThreadState *tstate)
+{
+    assert(_PyThreadState_CheckConsistency(tstate));
+    if (!_Py_ThreadCanHandleSignals(tstate->interp)) {
+        return 0;
+    }
+
+    UNSIGNAL_PENDING_SIGNALS(tstate->interp);
+    if (_PyErr_CheckSignalsTstate(tstate) < 0) {
+        /* On failure, re-schedule a call to handle_signals(). */
+        SIGNAL_PENDING_SIGNALS(tstate->interp, 0);
+        return -1;
+    }
+    return 0;
+}
+
+static inline int
+maybe_has_pending_calls(PyInterpreterState *interp)
+{
+    struct _pending_calls *pending = &interp->ceval.pending;
+    if (_Py_atomic_load_relaxed_int32(&pending->calls_to_do)) {
+        return 1;
+    }
+    if (!_Py_IsMainThread() || !_Py_IsMainInterpreter(interp)) {
+        return 0;
+    }
+    pending = &_PyRuntime.ceval.pending_mainthread;
+    return _Py_atomic_load_relaxed_int32(&pending->calls_to_do);
+}
+
+static int
+_make_pending_calls(struct _pending_calls *pending)
+{
+    /* perform a bounded number of calls, in case of recursion */
+    for (int i=0; i<NPENDINGCALLS; i++) {
+        int (*func)(void *) = NULL;
+        void *arg = NULL;
+
+        /* pop one item off the queue while holding the lock */
+        PyThread_acquire_lock(pending->lock, WAIT_LOCK);
+        _pop_pending_call(pending, &func, &arg);
+        PyThread_release_lock(pending->lock);
+
+        /* having released the lock, perform the callback */
+        if (func == NULL) {
+            break;
+        }
+        if (func(arg) != 0) {
+            return -1;
+        }
+    }
+    return 0;
+}
+
+static int
+make_pending_calls(PyInterpreterState *interp)
+{
+    struct _pending_calls *pending = &interp->ceval.pending;
+    struct _pending_calls *pending_main = &_PyRuntime.ceval.pending_mainthread;
+
+    /* Only one thread (per interpreter) may run the pending calls
+       at once.  In the same way, we don't do recursive pending calls. */
+    PyThread_acquire_lock(pending->lock, WAIT_LOCK);
+    if (pending->busy) {
+        /* A pending call was added after another thread was already
+           handling the pending calls (and had already "unsignaled").
+           Once that thread is done, it may have taken care of all the
+           pending calls, or there might be some still waiting.
+           Regardless, this interpreter's pending calls will stay
+           "signaled" until that first thread has finished.  At that
+           point the next thread to trip the eval breaker will take
+           care of any remaining pending calls.  Until then, though,
+           all the interpreter's threads will be tripping the eval
+           breaker every time it's checked. */
+        PyThread_release_lock(pending->lock);
+        return 0;
+    }
+    pending->busy = 1;
+    PyThread_release_lock(pending->lock);
+
+    /* unsignal before starting to call callbacks, so that any callback
+       added in-between re-signals */
+    UNSIGNAL_PENDING_CALLS(interp);
+
+    if (_make_pending_calls(pending) != 0) {
+        pending->busy = 0;
+        /* There might not be more calls to make, but we play it safe. */
+        SIGNAL_PENDING_CALLS(pending, interp);
+        return -1;
+    }
+
+    if (_Py_IsMainThread() && _Py_IsMainInterpreter(interp)) {
+        if (_make_pending_calls(pending_main) != 0) {
+            pending->busy = 0;
+            /* There might not be more calls to make, but we play it safe. */
+            SIGNAL_PENDING_CALLS(pending_main, interp);
+            return -1;
+        }
+    }
+
+    pending->busy = 0;
+    return 0;
+}
+
+void
+_Py_FinishPendingCalls(PyThreadState *tstate)
+{
+    assert(PyGILState_Check());
+    assert(_PyThreadState_CheckConsistency(tstate));
+
+    if (make_pending_calls(tstate->interp) < 0) {
+        PyObject *exc = _PyErr_GetRaisedException(tstate);
+        PyErr_BadInternalCall();
+        _PyErr_ChainExceptions1(exc);
+        _PyErr_Print(tstate);
+    }
+}
+
+int
+_PyEval_MakePendingCalls(PyThreadState *tstate)
+{
+    int res;
+
+    if (_Py_IsMainThread() && _Py_IsMainInterpreter(tstate->interp)) {
+        /* Python signal handler doesn't really queue a callback:
+           it only signals that a signal was received,
+           see _PyEval_SignalReceived(). */
+        res = handle_signals(tstate);
+        if (res != 0) {
+            return res;
+        }
+    }
+
+    res = make_pending_calls(tstate->interp);
+    if (res != 0) {
+        return res;
+    }
+
+    return 0;
+}
+
+/* Py_MakePendingCalls() is a simple wrapper for the sake
+   of backward-compatibility. */
+int
+Py_MakePendingCalls(void)
+{
+    assert(PyGILState_Check());
+
+    PyThreadState *tstate = _PyThreadState_GET();
+    assert(_PyThreadState_CheckConsistency(tstate));
+
+    /* Only execute pending calls on the main thread. */
+    if (!_Py_IsMainThread() || !_Py_IsMainInterpreter(tstate->interp)) {
+        return 0;
+    }
+    return _PyEval_MakePendingCalls(tstate);
+}
+
+void
+_PyEval_InitState(PyInterpreterState *interp, PyThread_type_lock pending_lock)
+{
+    _gil_initialize(&interp->_gil);
+
+    struct _pending_calls *pending = &interp->ceval.pending;
+    assert(pending->lock == NULL);
+    pending->lock = pending_lock;
+}
+
+void
+_PyEval_FiniState(struct _ceval_state *ceval)
+{
+    struct _pending_calls *pending = &ceval->pending;
+    if (pending->lock != NULL) {
+        PyThread_free_lock(pending->lock);
+        pending->lock = NULL;
+    }
+}
+
+/* Handle signals, pending calls, GIL drop request
+   and asynchronous exception */
+int
+_Py_HandlePending(PyThreadState *tstate)
+{
+    _PyRuntimeState * const runtime = &_PyRuntime;
+    struct _ceval_runtime_state *ceval = &runtime->ceval;
+    struct _ceval_state *interp_ceval_state = &tstate->interp->ceval;
+
+    /* Pending signals */
+    if (_Py_atomic_load_relaxed_int32(&ceval->signals_pending)) {
+        if (handle_signals(tstate) != 0) {
+            return -1;
+        }
+    }
+
+    /* Pending calls */
+    if (maybe_has_pending_calls(tstate->interp)) {
+        if (make_pending_calls(tstate->interp) != 0) {
+            return -1;
+        }
+    }
+
+    /* GC scheduled to run */
+    if (_Py_atomic_load_relaxed_int32(&interp_ceval_state->gc_scheduled)) {
+        _Py_atomic_store_relaxed(&interp_ceval_state->gc_scheduled, 0);
+        COMPUTE_EVAL_BREAKER(tstate->interp, ceval, interp_ceval_state);
+        _Py_RunGC(tstate);
+    }
+
+    /* GIL drop request */
+    if (_Py_atomic_load_relaxed_int32(&interp_ceval_state->gil_drop_request)) {
+        /* Give another thread a chance */
+        if (_PyThreadState_SwapNoGIL(NULL) != tstate) {
+            Py_FatalError("tstate mix-up");
+        }
+        drop_gil(interp_ceval_state, tstate);
+
+        /* Other threads may run now */
+
+        take_gil(tstate);
+
+        if (_PyThreadState_SwapNoGIL(tstate) != NULL) {
+            Py_FatalError("orphan tstate");
+        }
+    }
+
+    /* Check for asynchronous exception. */
+    if (tstate->async_exc != NULL) {
+        PyObject *exc = tstate->async_exc;
+        tstate->async_exc = NULL;
+        UNSIGNAL_ASYNC_EXC(tstate->interp);
+        _PyErr_SetNone(tstate, exc);
+        Py_DECREF(exc);
+        return -1;
+    }
+
+
+    // It is possible that some of the conditions that trigger the eval breaker
+    // are called in a different thread than the Python thread. An example of
+    // this is bpo-42296: On Windows, _PyEval_SignalReceived() can be called in
+    // a different thread than the Python thread, in which case
+    // _Py_ThreadCanHandleSignals() is wrong. Recompute eval_breaker in the
+    // current Python thread with the correct _Py_ThreadCanHandleSignals()
+    // value. It prevents to interrupt the eval loop at every instruction if
+    // the current Python thread cannot handle signals (if
+    // _Py_ThreadCanHandleSignals() is false).
+    COMPUTE_EVAL_BREAKER(tstate->interp, ceval, interp_ceval_state);
+
+    return 0;
+}
+