bpo-30860: Consolidate stateful runtime globals. (#2594)

* group the (stateful) runtime globals into various topical structs
* consolidate the topical structs under a single top-level _PyRuntimeState struct
* add a check-c-globals.py script that helps identify runtime globals

Other globals are excluded (see globals.txt and check-c-globals.py).

Include/Python.h

@@ -133,4 +133,8 @@
 #include "fileutils.h"
 #include "pyfpe.h"
 
+#ifdef Py_BUILD_CORE
+#include "internal/_Python.h"
+#endif
+
 #endif /* !Py_PYTHON_H */

Include/ceval.h

@@ -93,7 +93,12 @@ PyAPI_FUNC(int) Py_GetRecursionLimit(void);
       PyThreadState_GET()->overflowed = 0;  \
     } while(0)
 PyAPI_FUNC(int) _Py_CheckRecursiveCall(const char *where);
-PyAPI_DATA(int) _Py_CheckRecursionLimit;
+#ifdef Py_BUILD_CORE
+#define _Py_CheckRecursionLimit _PyRuntime.ceval.check_recursion_limit
+#else
+PyAPI_FUNC(int) _PyEval_CheckRecursionLimit(void);
+#define _Py_CheckRecursionLimit _PyEval_CheckRecursionLimit()
+#endif
 
 #ifdef USE_STACKCHECK
 /* With USE_STACKCHECK, we artificially decrement the recursion limit in order

Include/internal/_Python.h

+#ifndef _Py_PYTHON_H
+#define _Py_PYTHON_H
+/* Since this is a "meta-include" file, no #ifdef __cplusplus / extern "C" { */
+
+/* Include all internal Python header files */
+
+#ifndef Py_BUILD_CORE
+#error "Internal headers are not available externally."
+#endif
+
+#include "_mem.h"
+#include "_ceval.h"
+#include "_warnings.h"
+#include "_pystate.h"
+
+#endif /* !_Py_PYTHON_H */

Include/internal/_ceval.h

+#ifndef _Py_CEVAL_H
+#define _Py_CEVAL_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "ceval.h"
+#include "compile.h"
+#include "pyatomic.h"
+
+#ifdef WITH_THREAD
+#include "pythread.h"
+#endif
+
+struct _pending_calls {
+    unsigned long main_thread;
+#ifdef WITH_THREAD
+    PyThread_type_lock lock;
+    /* Request for running pending calls. */
+    _Py_atomic_int calls_to_do;
+    /* Request for looking at the `async_exc` field of the current
+       thread state.
+       Guarded by the GIL. */
+    int async_exc;
+#define NPENDINGCALLS 32
+    struct {
+        int (*func)(void *);
+        void *arg;
+    } calls[NPENDINGCALLS];
+    int first;
+    int last;
+#else /* ! WITH_THREAD */
+    _Py_atomic_int calls_to_do;
+#define NPENDINGCALLS 32
+    struct {
+        int (*func)(void *);
+        void *arg;
+    } calls[NPENDINGCALLS];
+    volatile int first;
+    volatile int last;
+#endif /* WITH_THREAD */
+};
+
+#include "_gil.h"
+
+struct _ceval_runtime_state {
+    int recursion_limit;
+    int check_recursion_limit;
+    /* Records whether tracing is on for any thread.  Counts the number
+       of threads for which tstate->c_tracefunc is non-NULL, so if the
+       value is 0, we know we don't have to check this thread's
+       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;
+#ifdef WITH_THREAD
+    /* Request for dropping the GIL */
+    _Py_atomic_int gil_drop_request;
+#endif
+    struct _pending_calls pending;
+    struct _gil_runtime_state gil;
+};
+
+PyAPI_FUNC(void) _PyEval_Initialize(struct _ceval_runtime_state *);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !_Py_CEVAL_H */

Include/internal/_condvar.h

+#ifndef _CONDVAR_H_
+#define _CONDVAR_H_
+
+#ifndef _POSIX_THREADS
+/* This means pthreads are not implemented in libc headers, hence the macro
+   not present in unistd.h. But they still can be implemented as an external
+   library (e.g. gnu pth in pthread emulation) */
+# ifdef HAVE_PTHREAD_H
+#  include <pthread.h> /* _POSIX_THREADS */
+# endif
+#endif
+
+#ifdef _POSIX_THREADS
+/*
+ * POSIX support
+ */
+#define Py_HAVE_CONDVAR
+
+#include <pthread.h>
+
+#define PyMUTEX_T pthread_mutex_t
+#define PyCOND_T pthread_cond_t
+
+#elif defined(NT_THREADS)
+/*
+ * Windows (XP, 2003 server and later, as well as (hopefully) CE) support
+ *
+ * Emulated condition variables ones that work with XP and later, plus
+ * example native support on VISTA and onwards.
+ */
+#define Py_HAVE_CONDVAR
+
+/* include windows if it hasn't been done before */
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+
+/* options */
+/* non-emulated condition variables are provided for those that want
+ * to target Windows Vista.  Modify this macro to enable them.
+ */
+#ifndef _PY_EMULATED_WIN_CV
+#define _PY_EMULATED_WIN_CV 1  /* use emulated condition variables */
+#endif
+
+/* fall back to emulation if not targeting Vista */
+#if !defined NTDDI_VISTA || NTDDI_VERSION < NTDDI_VISTA
+#undef _PY_EMULATED_WIN_CV
+#define _PY_EMULATED_WIN_CV 1
+#endif
+
+#if _PY_EMULATED_WIN_CV
+
+typedef CRITICAL_SECTION PyMUTEX_T;
+
+/* The ConditionVariable object.  From XP onwards it is easily emulated
+   with a Semaphore.
+   Semaphores are available on Windows XP (2003 server) and later.
+   We use a Semaphore rather than an auto-reset event, because although
+   an auto-resent event might appear to solve the lost-wakeup bug (race
+   condition between releasing the outer lock and waiting) because it
+   maintains state even though a wait hasn't happened, there is still
+   a lost wakeup problem if more than one thread are interrupted in the
+   critical place.  A semaphore solves that, because its state is
+   counted, not Boolean.
+   Because it is ok to signal a condition variable with no one
+   waiting, we need to keep track of the number of
+   waiting threads.  Otherwise, the semaphore's state could rise
+   without bound.  This also helps reduce the number of "spurious wakeups"
+   that would otherwise happen.
+ */
+
+typedef struct _PyCOND_T
+{
+    HANDLE sem;
+    int waiting; /* to allow PyCOND_SIGNAL to be a no-op */
+} PyCOND_T;
+
+#else /* !_PY_EMULATED_WIN_CV */
+
+/* Use native Win7 primitives if build target is Win7 or higher */
+
+/* SRWLOCK is faster and better than CriticalSection */
+typedef SRWLOCK PyMUTEX_T;
+
+typedef CONDITION_VARIABLE  PyCOND_T;
+
+#endif /* _PY_EMULATED_WIN_CV */
+
+#endif /* _POSIX_THREADS, NT_THREADS */
+
+#endif /* _CONDVAR_H_ */

Include/internal/_gil.h

+#ifndef _Py_GIL_H
+#define _Py_GIL_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "pyatomic.h"
+
+#include "internal/_condvar.h"
+#ifndef Py_HAVE_CONDVAR
+#error You need either a POSIX-compatible or a Windows system!
+#endif
+
+/* Enable if you want to force the switching of threads at least
+   every `interval`. */
+#undef FORCE_SWITCHING
+#define FORCE_SWITCHING
+
+struct _gil_runtime_state {
+    /* microseconds (the Python API uses seconds, though) */
+    unsigned long interval;
+    /* Last PyThreadState holding / having held the GIL. This helps us
+       know whether anyone else was scheduled after we dropped the GIL. */
+    _Py_atomic_address last_holder;
+    /* Whether the GIL is already taken (-1 if uninitialized). This is
+       atomic because it can be read without any lock taken in ceval.c. */
+    _Py_atomic_int locked;
+    /* Number of GIL switches since the beginning. */
+    unsigned long switch_number;
+#ifdef WITH_THREAD
+    /* This condition variable allows one or several threads to wait
+       until the GIL is released. In addition, the mutex also protects
+       the above variables. */
+    PyCOND_T cond;
+    PyMUTEX_T mutex;
+#ifdef FORCE_SWITCHING
+    /* This condition variable helps the GIL-releasing thread wait for
+       a GIL-awaiting thread to be scheduled and take the GIL. */
+    PyCOND_T switch_cond;
+    PyMUTEX_T switch_mutex;
+#endif
+#endif /* WITH_THREAD */
+};
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !_Py_GIL_H */

Include/internal/_mem.h

+#ifndef _Py_MEM_H
+#define _Py_MEM_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "objimpl.h"
+#include "pymem.h"
+
+#ifdef WITH_PYMALLOC
+#include "_pymalloc.h"
+#endif
+
+/* Low-level memory runtime state */
+
+struct _pymem_runtime_state {
+    struct _allocator_runtime_state {
+        PyMemAllocatorEx mem;
+        PyMemAllocatorEx obj;
+        PyMemAllocatorEx raw;
+    } allocators;
+#ifdef WITH_PYMALLOC
+    /* Array of objects used to track chunks of memory (arenas). */
+    struct arena_object* arenas;
+    /* The head of the singly-linked, NULL-terminated list of available
+       arena_objects. */
+    struct arena_object* unused_arena_objects;
+    /* The head of the doubly-linked, NULL-terminated at each end,
+       list of arena_objects associated with arenas that have pools
+       available. */
+    struct arena_object* usable_arenas;
+    /* Number of slots currently allocated in the `arenas` vector. */
+    unsigned int maxarenas;
+    /* Number of arenas allocated that haven't been free()'d. */
+    size_t narenas_currently_allocated;
+    /* High water mark (max value ever seen) for
+     * narenas_currently_allocated. */
+    size_t narenas_highwater;
+    /* Total number of times malloc() called to allocate an arena. */
+    size_t ntimes_arena_allocated;
+    poolp usedpools[MAX_POOLS];
+    Py_ssize_t num_allocated_blocks;
+    size_t serialno;     /* incremented on each debug {m,re}alloc */
+#endif /* WITH_PYMALLOC */
+};
+
+PyAPI_FUNC(void) _PyMem_Initialize(struct _pymem_runtime_state *);
+
+
+/* High-level memory runtime state */
+
+struct _pyobj_runtime_state {
+    PyObjectArenaAllocator allocator_arenas;
+};
+
+PyAPI_FUNC(void) _PyObject_Initialize(struct _pyobj_runtime_state *);
+
+
+/* GC runtime state */
+
+/* If we change this, we need to change the default value in the
+   signature of gc.collect. */
+#define NUM_GENERATIONS 3
+
+/*
+   NOTE: about the counting of long-lived objects.
+
+   To limit the cost of garbage collection, there are two strategies;
+     - make each collection faster, e.g. by scanning fewer objects
+     - do less collections
+   This heuristic is about the latter strategy.
+
+   In addition to the various configurable thresholds, we only trigger a
+   full collection if the ratio
+    long_lived_pending / long_lived_total
+   is above a given value (hardwired to 25%).
+
+   The reason is that, while "non-full" collections (i.e., collections of
+   the young and middle generations) will always examine roughly the same
+   number of objects -- determined by the aforementioned thresholds --,
+   the cost of a full collection is proportional to the total number of
+   long-lived objects, which is virtually unbounded.
+
+   Indeed, it has been remarked that doing a full collection every
+   <constant number> of object creations entails a dramatic performance
+   degradation in workloads which consist in creating and storing lots of
+   long-lived objects (e.g. building a large list of GC-tracked objects would
+   show quadratic performance, instead of linear as expected: see issue #4074).
+
+   Using the above ratio, instead, yields amortized linear performance in
+   the total number of objects (the effect of which can be summarized
+   thusly: "each full garbage collection is more and more costly as the
+   number of objects grows, but we do fewer and fewer of them").
+
+   This heuristic was suggested by Martin von Löwis on python-dev in
+   June 2008. His original analysis and proposal can be found at:
+    http://mail.python.org/pipermail/python-dev/2008-June/080579.html
+*/
+
+/*
+   NOTE: about untracking of mutable objects.
+
+   Certain types of container cannot participate in a reference cycle, and
+   so do not need to be tracked by the garbage collector. Untracking these
+   objects reduces the cost of garbage collections. However, determining
+   which objects may be untracked is not free, and the costs must be
+   weighed against the benefits for garbage collection.
+
+   There are two possible strategies for when to untrack a container:
+
+   i) When the container is created.
+   ii) When the container is examined by the garbage collector.
+
+   Tuples containing only immutable objects (integers, strings etc, and
+   recursively, tuples of immutable objects) do not need to be tracked.
+   The interpreter creates a large number of tuples, many of which will
+   not survive until garbage collection. It is therefore not worthwhile
+   to untrack eligible tuples at creation time.
+
+   Instead, all tuples except the empty tuple are tracked when created.
+   During garbage collection it is determined whether any surviving tuples
+   can be untracked. A tuple can be untracked if all of its contents are
+   already not tracked. Tuples are examined for untracking in all garbage
+   collection cycles. It may take more than one cycle to untrack a tuple.
+
+   Dictionaries containing only immutable objects also do not need to be
+   tracked. Dictionaries are untracked when created. If a tracked item is
+   inserted into a dictionary (either as a key or value), the dictionary
+   becomes tracked. During a full garbage collection (all generations),
+   the collector will untrack any dictionaries whose contents are not
+   tracked.
+
+   The module provides the python function is_tracked(obj), which returns
+   the CURRENT tracking status of the object. Subsequent garbage
+   collections may change the tracking status of the object.
+
+   Untracking of certain containers was introduced in issue #4688, and
+   the algorithm was refined in response to issue #14775.
+*/
+
+struct gc_generation {
+    PyGC_Head head;
+    int threshold; /* collection threshold */
+    int count; /* count of allocations or collections of younger
+                  generations */
+};
+
+/* Running stats per generation */
+struct gc_generation_stats {
+    /* total number of collections */
+    Py_ssize_t collections;
+    /* total number of collected objects */
+    Py_ssize_t collected;
+    /* total number of uncollectable objects (put into gc.garbage) */
+    Py_ssize_t uncollectable;
+};
+
+struct _gc_runtime_state {
+    /* List of objects that still need to be cleaned up, singly linked
+     * via their gc headers' gc_prev pointers.  */
+    PyObject *trash_delete_later;
+    /* Current call-stack depth of tp_dealloc calls. */
+    int trash_delete_nesting;
+
+    int enabled;
+    int debug;
+    /* linked lists of container objects */
+    struct gc_generation generations[NUM_GENERATIONS];
+    PyGC_Head *generation0;
+    struct gc_generation_stats generation_stats[NUM_GENERATIONS];
+    /* true if we are currently running the collector */
+    int collecting;
+    /* list of uncollectable objects */
+    PyObject *garbage;
+    /* a list of callbacks to be invoked when collection is performed */
+    PyObject *callbacks;
+    /* This is the number of objects that survived the last full
+       collection. It approximates the number of long lived objects
+       tracked by the GC.
+
+       (by "full collection", we mean a collection of the oldest
+       generation). */
+    Py_ssize_t long_lived_total;
+    /* This is the number of objects that survived all "non-full"
+       collections, and are awaiting to undergo a full collection for
+       the first time. */
+    Py_ssize_t long_lived_pending;
+};
+
+PyAPI_FUNC(void) _PyGC_Initialize(struct _gc_runtime_state *);
+
+#define _PyGC_generation0 _PyRuntime.gc.generation0
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !_Py_MEM_H */

Include/internal/_pystate.h

+#ifndef _Py_PYSTATE_H
+#define _Py_PYSTATE_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "pystate.h"
+#include "pyatomic.h"
+
+#ifdef WITH_THREAD
+#include "pythread.h"
+#endif
+
+#include "_mem.h"
+#include "_ceval.h"
+#include "_warnings.h"
+
+
+/* GIL state */
+
+struct _gilstate_runtime_state {
+    int check_enabled;
+    /* Assuming the current thread holds the GIL, this is the
+       PyThreadState for the current thread. */
+    _Py_atomic_address tstate_current;
+    PyThreadFrameGetter getframe;
+#ifdef WITH_THREAD
+    /* The single PyInterpreterState used by this process'
+       GILState implementation
+    */
+    /* TODO: Given interp_main, it may be possible to kill this ref */
+    PyInterpreterState *autoInterpreterState;
+    int autoTLSkey;
+#endif /* WITH_THREAD */
+};
+
+/* hook for PyEval_GetFrame(), requested for Psyco */
+#define _PyThreadState_GetFrame _PyRuntime.gilstate.getframe
+
+/* Issue #26558: Flag to disable PyGILState_Check().
+   If set to non-zero, PyGILState_Check() always return 1. */
+#define _PyGILState_check_enabled _PyRuntime.gilstate.check_enabled
+
+
+/* Full Python runtime state */
+
+typedef struct pyruntimestate {
+    int initialized;
+    int core_initialized;
+    PyThreadState *finalizing;
+
+    struct pyinterpreters {
+#ifdef WITH_THREAD
+        PyThread_type_lock mutex;
+#endif
+        PyInterpreterState *head;
+        PyInterpreterState *main;
+        /* _next_interp_id is an auto-numbered sequence of small
+           integers.  It gets initialized in _PyInterpreterState_Init(),
+           which is called in Py_Initialize(), and used in
+           PyInterpreterState_New().  A negative interpreter ID
+           indicates an error occurred.  The main interpreter will
+           always have an ID of 0.  Overflow results in a RuntimeError.
+           If that becomes a problem later then we can adjust, e.g. by
+           using a Python int. */
+        int64_t next_id;
+    } interpreters;
+
+#define NEXITFUNCS 32
+    void (*exitfuncs[NEXITFUNCS])(void);
+    int nexitfuncs;
+    void (*pyexitfunc)(void);
+
+    struct _pyobj_runtime_state obj;
+    struct _gc_runtime_state gc;
+    struct _pymem_runtime_state mem;
+    struct _warnings_runtime_state warnings;
+    struct _ceval_runtime_state ceval;
+    struct _gilstate_runtime_state gilstate;
+
+    // XXX Consolidate globals found via the check-c-globals script.
+} _PyRuntimeState;
+
+PyAPI_DATA(_PyRuntimeState) _PyRuntime;
+PyAPI_FUNC(void) _PyRuntimeState_Init(_PyRuntimeState *);
+PyAPI_FUNC(void) _PyRuntimeState_Fini(_PyRuntimeState *);
+
+PyAPI_FUNC(void) _PyInterpreterState_Enable(_PyRuntimeState *);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !_Py_PYSTATE_H */

Include/internal/_warnings.h

+#ifndef _Py_WARNINGS_H
+#define _Py_WARNINGS_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "object.h"
+
+struct _warnings_runtime_state {
+    /* Both 'filters' and 'onceregistry' can be set in warnings.py;
+       get_warnings_attr() will reset these variables accordingly. */
+    PyObject *filters;  /* List */
+    PyObject *once_registry;  /* Dict */
+    PyObject *default_action; /* String */
+    long filters_version;
+};
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !_Py_WARNINGS_H */

Include/object.h

@@ -1038,8 +1038,6 @@ with the call stack never exceeding a depth of PyTrash_UNWIND_LEVEL.
    Kept for binary compatibility of extensions using the stable ABI. */
 PyAPI_FUNC(void) _PyTrash_deposit_object(PyObject*);
 PyAPI_FUNC(void) _PyTrash_destroy_chain(void);
-PyAPI_DATA(int) _PyTrash_delete_nesting;
-PyAPI_DATA(PyObject *) _PyTrash_delete_later;
 #endif /* !Py_LIMITED_API */
 
 /* The new thread-safe private API, invoked by the macros below. */

Include/pylifecycle.h

@@ -119,7 +119,10 @@ PyAPI_FUNC(void) _PyType_Fini(void);
 PyAPI_FUNC(void) _Py_HashRandomization_Fini(void);
 PyAPI_FUNC(void) PyAsyncGen_Fini(void);
 
-PyAPI_DATA(PyThreadState *) _Py_Finalizing;
+#define _Py_IS_FINALIZING() \
+    (_PyRuntime.finalizing != NULL)
+#define _Py_CURRENTLY_FINALIZING(tstate) \
+    (_PyRuntime.finalizing == tstate)
 #endif
 
 /* Signals */

Include/pystate.h

@@ -29,9 +29,10 @@ typedef struct {
     int use_hash_seed;
     unsigned long hash_seed;
     int _disable_importlib; /* Needed by freeze_importlib */
+    char *allocator;
 } _PyCoreConfig;
 
-#define _PyCoreConfig_INIT {0, -1, 0, 0}
+#define _PyCoreConfig_INIT {0, -1, 0, 0, NULL}
 
 /* Placeholders while working on the new configuration API
  *
@@ -57,6 +58,19 @@ typedef struct _is {
     PyObject *builtins;
     PyObject *importlib;
 
+    /* Used in Python/sysmodule.c. */
+    int check_interval;
+    PyObject *warnoptions;
+    PyObject *xoptions;
+
+    /* Used in Modules/_threadmodule.c. */
+    long num_threads;
+    /* Support for runtime thread stack size tuning.
+       A value of 0 means using the platform's default stack size
+       or the size specified by the THREAD_STACK_SIZE macro. */
+    /* Used in Python/thread.c. */
+    size_t pythread_stacksize;
+
     PyObject *codec_search_path;
     PyObject *codec_search_cache;
     PyObject *codec_error_registry;
@@ -185,9 +199,6 @@ typedef struct _ts {
 #endif
 
 
-#ifndef Py_LIMITED_API
-PyAPI_FUNC(void) _PyInterpreterState_Init(void);
-#endif /* !Py_LIMITED_API */
 PyAPI_FUNC(PyInterpreterState *) PyInterpreterState_New(void);
 PyAPI_FUNC(void) PyInterpreterState_Clear(PyInterpreterState *);
 PyAPI_FUNC(void) PyInterpreterState_Delete(PyInterpreterState *);
@@ -246,7 +257,7 @@ PyAPI_FUNC(int) PyThreadState_SetAsyncExc(unsigned long, PyObject *);
 /* Assuming the current thread holds the GIL, this is the
    PyThreadState for the current thread. */
 #ifdef Py_BUILD_CORE
-PyAPI_DATA(_Py_atomic_address) _PyThreadState_Current;
+#  define _PyThreadState_Current _PyRuntime.gilstate.tstate_current
 #  define PyThreadState_GET() \
              ((PyThreadState*)_Py_atomic_load_relaxed(&_PyThreadState_Current))
 #else
@@ -301,10 +312,6 @@ PyAPI_FUNC(void) PyGILState_Release(PyGILState_STATE);
 PyAPI_FUNC(PyThreadState *) PyGILState_GetThisThreadState(void);
 
 #ifndef Py_LIMITED_API
-/* Issue #26558: Flag to disable PyGILState_Check().
-   If set to non-zero, PyGILState_Check() always return 1. */
-PyAPI_DATA(int) _PyGILState_check_enabled;
-
 /* Helper/diagnostic function - return 1 if the current thread
    currently holds the GIL, 0 otherwise.
 
@@ -340,11 +347,6 @@ PyAPI_FUNC(PyThreadState *) PyThreadState_Next(PyThreadState *);
 typedef struct _frame *(*PyThreadFrameGetter)(PyThreadState *self_);
 #endif
 
-/* hook for PyEval_GetFrame(), requested for Psyco */
-#ifndef Py_LIMITED_API
-PyAPI_DATA(PyThreadFrameGetter) _PyThreadState_GetFrame;
-#endif
-
 #ifdef __cplusplus
 }
 #endif

Makefile.pre.in

@@ -987,6 +987,13 @@ PYTHON_HEADERS= \
 		pyconfig.h \
 		$(PARSER_HEADERS) \
 		$(srcdir)/Include/Python-ast.h \
+		$(srcdir)/Include/internal/_Python.h \
+		$(srcdir)/Include/internal/_ceval.h \
+		$(srcdir)/Include/internal/_gil.h \
+		$(srcdir)/Include/internal/_mem.h \
+		$(srcdir)/Include/internal/_pymalloc.h \
+		$(srcdir)/Include/internal/_pystate.h \
+		$(srcdir)/Include/internal/_warnings.h \
 		$(DTRACE_HEADERS)
 
 $(LIBRARY_OBJS) $(MODOBJS) Programs/python.o: $(PYTHON_HEADERS)

Misc/NEWS.d/next/Core and Builtins/2017-09-05-13-47-49.bpo-30860.MROpZw.rst

+Consolidate CPython's global runtime state under a single struct.  This
+improves discoverability of the runtime state.

Modules/_io/bufferedio.c

@@ -279,7 +279,7 @@ _enter_buffered_busy(buffered *self)
                      "reentrant call inside %R", self);
         return 0;
     }
-    relax_locking = (_Py_Finalizing != NULL);
+    relax_locking = _Py_IS_FINALIZING();
     Py_BEGIN_ALLOW_THREADS
     if (!relax_locking)
         st = PyThread_acquire_lock(self->lock, 1);

Modules/_threadmodule.c

@@ -14,7 +14,6 @@
 #include "pythread.h"
 
 static PyObject *ThreadError;
-static long nb_threads = 0;
 static PyObject *str_dict;
 
 _Py_IDENTIFIER(stderr);
@@ -993,7 +992,7 @@ t_bootstrap(void *boot_raw)
     tstate->thread_id = PyThread_get_thread_ident();
     _PyThreadState_Init(tstate);
     PyEval_AcquireThread(tstate);
-    nb_threads++;
+    tstate->interp->num_threads++;
     res = PyObject_Call(boot->func, boot->args, boot->keyw);
     if (res == NULL) {
         if (PyErr_ExceptionMatches(PyExc_SystemExit))
@@ -1020,7 +1019,7 @@ t_bootstrap(void *boot_raw)
     Py_DECREF(boot->args);
     Py_XDECREF(boot->keyw);
     PyMem_DEL(boot_raw);
-    nb_threads--;
+    tstate->interp->num_threads--;
     PyThreadState_Clear(tstate);
     PyThreadState_DeleteCurrent();
     PyThread_exit_thread();
@@ -1159,7 +1158,8 @@ A thread's identity may be reused for another thread after it exits.");
 static PyObject *
 thread__count(PyObject *self)
 {
-    return PyLong_FromLong(nb_threads);
+    PyThreadState *tstate = PyThreadState_Get();
+    return PyLong_FromLong(tstate->interp->num_threads);
 }
 
 PyDoc_STRVAR(_count_doc,
@@ -1352,6 +1352,7 @@ PyInit__thread(void)
     PyObject *m, *d, *v;
     double time_max;
     double timeout_max;
+    PyThreadState *tstate = PyThreadState_Get();
 
     /* Initialize types: */
     if (PyType_Ready(&localdummytype) < 0)
@@ -1396,7 +1397,7 @@ PyInit__thread(void)
     if (PyModule_AddObject(m, "_local", (PyObject *)&localtype) < 0)
         return NULL;
 
-    nb_threads = 0;
+    tstate->interp->num_threads = 0;
 
     str_dict = PyUnicode_InternFromString("__dict__");
     if (str_dict == NULL)

Modules/_winapi.c

@@ -114,7 +114,7 @@ overlapped_dealloc(OverlappedObject *self)
         {
             /* The operation is no longer pending -- nothing to do. */
         }
-        else if (_Py_Finalizing == NULL)
+        else if _Py_IS_FINALIZING()
         {
             /* The operation is still pending -- give a warning.  This
                will probably only happen on Windows XP. */

Modules/main.c

@@ -598,16 +598,10 @@ Py_Main(int argc, wchar_t **argv)
         }
     }
 
-    char *pymalloc = Py_GETENV("PYTHONMALLOC");
-    if (_PyMem_SetupAllocators(pymalloc) < 0) {
-        fprintf(stderr,
-            "Error in PYTHONMALLOC: unknown allocator \"%s\"!\n", pymalloc);
-        exit(1);
-    }
-
     /* Initialize the core language runtime */
     Py_IgnoreEnvironmentFlag = core_config.ignore_environment;
     core_config._disable_importlib = 0;
+    core_config.allocator = Py_GETENV("PYTHONMALLOC");
     _Py_InitializeCore(&core_config);
 
     /* Reprocess the command line with the language runtime available */

Objects/object.c

@@ -2028,14 +2028,6 @@ finally:
 
 /* Trashcan support. */
 
-/* Current call-stack depth of tp_dealloc calls. */
-int _PyTrash_delete_nesting = 0;
-
-/* List of objects that still need to be cleaned up, singly linked via their
- * gc headers' gc_prev pointers.
- */
-PyObject *_PyTrash_delete_later = NULL;
-
 /* Add op to the _PyTrash_delete_later list.  Called when the current
  * call-stack depth gets large.  op must be a currently untracked gc'ed
  * object, with refcount 0.  Py_DECREF must already have been called on it.
@@ -2046,8 +2038,8 @@ _PyTrash_deposit_object(PyObject *op)
     assert(PyObject_IS_GC(op));
     assert(_PyGC_REFS(op) == _PyGC_REFS_UNTRACKED);
     assert(op->ob_refcnt == 0);
-    _Py_AS_GC(op)->gc.gc_prev = (PyGC_Head *)_PyTrash_delete_later;
-    _PyTrash_delete_later = op;
+    _Py_AS_GC(op)->gc.gc_prev = (PyGC_Head *)_PyRuntime.gc.trash_delete_later;
+    _PyRuntime.gc.trash_delete_later = op;
 }
 
 /* The equivalent API, using per-thread state recursion info */
@@ -2068,11 +2060,11 @@ _PyTrash_thread_deposit_object(PyObject *op)
 void
 _PyTrash_destroy_chain(void)
 {
-    while (_PyTrash_delete_later) {
-        PyObject *op = _PyTrash_delete_later;
+    while (_PyRuntime.gc.trash_delete_later) {
+        PyObject *op = _PyRuntime.gc.trash_delete_later;
         destructor dealloc = Py_TYPE(op)->tp_dealloc;
 
-        _PyTrash_delete_later =
+        _PyRuntime.gc.trash_delete_later =
             (PyObject*) _Py_AS_GC(op)->gc.gc_prev;
 
         /* Call the deallocator directly.  This used to try to
@@ -2082,9 +2074,9 @@ _PyTrash_destroy_chain(void)
          * up distorting allocation statistics.
          */
         assert(op->ob_refcnt == 0);
-        ++_PyTrash_delete_nesting;
+        ++_PyRuntime.gc.trash_delete_nesting;
         (*dealloc)(op);
-        --_PyTrash_delete_nesting;
+        --_PyRuntime.gc.trash_delete_nesting;
     }
 }
 

Objects/setobject.c

@@ -1115,6 +1115,7 @@ frozenset_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     }
     /* The empty frozenset is a singleton */
     if (emptyfrozenset == NULL)
+        /* There is a possible (relatively harmless) race here. */
         emptyfrozenset = make_new_set(type, NULL);
     Py_XINCREF(emptyfrozenset);
     return emptyfrozenset;

Objects/typeobject.c

@@ -1157,10 +1157,10 @@ subtype_dealloc(PyObject *self)
     /* UnTrack and re-Track around the trashcan macro, alas */
     /* See explanation at end of function for full disclosure */
     PyObject_GC_UnTrack(self);
-    ++_PyTrash_delete_nesting;
+    ++_PyRuntime.gc.trash_delete_nesting;
     ++ tstate->trash_delete_nesting;
     Py_TRASHCAN_SAFE_BEGIN(self);
-    --_PyTrash_delete_nesting;
+    --_PyRuntime.gc.trash_delete_nesting;
     -- tstate->trash_delete_nesting;
 
     /* Find the nearest base with a different tp_dealloc */
@@ -1254,10 +1254,10 @@ subtype_dealloc(PyObject *self)
       Py_DECREF(type);
 
   endlabel:
-    ++_PyTrash_delete_nesting;
+    ++_PyRuntime.gc.trash_delete_nesting;
     ++ tstate->trash_delete_nesting;
     Py_TRASHCAN_SAFE_END(self);
-    --_PyTrash_delete_nesting;
+    --_PyRuntime.gc.trash_delete_nesting;
     -- tstate->trash_delete_nesting;
 
     /* Explanation of the weirdness around the trashcan macros:
@@ -1297,7 +1297,7 @@ subtype_dealloc(PyObject *self)
           a subtle disaster.
 
        Q. Why the bizarre (net-zero) manipulation of
-          _PyTrash_delete_nesting around the trashcan macros?
+          _PyRuntime.trash_delete_nesting around the trashcan macros?
 
        A. Some base classes (e.g. list) also use the trashcan mechanism.
           The following scenario used to be possible:

PCbuild/pythoncore.vcxproj

@@ -106,6 +106,14 @@
     <ClInclude Include="..\Include\graminit.h" />
     <ClInclude Include="..\Include\grammar.h" />
     <ClInclude Include="..\Include\import.h" />
+    <ClInclude Include="..\Include\internal\_Python.h" />
+    <ClInclude Include="..\Include\internal\_ceval.h" />
+    <ClInclude Include="..\Include\internal\_condvar.h" />
+    <ClInclude Include="..\Include\internal\_gil.h" />
+    <ClInclude Include="..\Include\internal\_mem.h" />
+    <ClInclude Include="..\Include\internal\_pymalloc.h" />
+    <ClInclude Include="..\Include\internal\_pystate.h" />
+    <ClInclude Include="..\Include\internal\_warnings.h" />
     <ClInclude Include="..\Include\intrcheck.h" />
     <ClInclude Include="..\Include\iterobject.h" />
     <ClInclude Include="..\Include\listobject.h" />

PCbuild/pythoncore.vcxproj.filters

@@ -129,6 +129,30 @@
     <ClInclude Include="..\Include\import.h">
       <Filter>Include</Filter>
     </ClInclude>
+    <ClInclude Include="..\Include\internal\_Python.h">
+      <Filter>Include</Filter>
+    </ClInclude>
+    <ClInclude Include="..\Include\internal\_ceval.h">
+      <Filter>Include</Filter>
+    </ClInclude>
+    <ClInclude Include="..\Include\internal\_condvar.h">
+      <Filter>Include</Filter>
+    </ClInclude>
+    <ClInclude Include="..\Include\internal\_gil.h">
+      <Filter>Include</Filter>
+    </ClInclude>
+    <ClInclude Include="..\Include\internal\_mem.h">
+      <Filter>Include</Filter>
+    </ClInclude>
+    <ClInclude Include="..\Include\internal\_pymalloc.h">
+      <Filter>Include</Filter>
+    </ClInclude>
+    <ClInclude Include="..\Include\internal\_pystate.h">
+      <Filter>Include</Filter>
+    </ClInclude>
+    <ClInclude Include="..\Include\internal\_warnings.h">
+      <Filter>Include</Filter>
+    </ClInclude>
     <ClInclude Include="..\Include\intrcheck.h">
       <Filter>Include</Filter>
     </ClInclude>

Parser/pgenmain.c

@@ -21,10 +21,12 @@
 #include "node.h"
 #include "parsetok.h"
 #include "pgen.h"
+#include "internal/_mem.h"
 
 int Py_DebugFlag;
 int Py_VerboseFlag;
 int Py_IgnoreEnvironmentFlag;
+struct pyruntimestate _PyRuntime = {};
 
 /* Forward */
 grammar *getgrammar(const char *filename);
@@ -61,6 +63,8 @@ main(int argc, char **argv)
     filename = argv[1];
     graminit_h = argv[2];
     graminit_c = argv[3];
+    _PyObject_Initialize(&_PyRuntime.obj);
+    _PyMem_Initialize(&_PyRuntime.mem);
     g = getgrammar(filename);
     fp = fopen(graminit_c, "w");
     if (fp == NULL) {

Python/_warnings.c

@@ -8,13 +8,6 @@ PyDoc_STRVAR(warnings__doc__,
 MODULE_NAME " provides basic warning filtering support.\n"
 "It is a helper module to speed up interpreter start-up.");
 
-/* Both 'filters' and 'onceregistry' can be set in warnings.py;
-   get_warnings_attr() will reset these variables accordingly. */
-static PyObject *_filters;  /* List */
-static PyObject *_once_registry;  /* Dict */
-static PyObject *_default_action; /* String */
-static long _filters_version;
-
 _Py_IDENTIFIER(argv);
 _Py_IDENTIFIER(stderr);
 
@@ -53,7 +46,7 @@ get_warnings_attr(const char *attr, int try_import)
     }
 
     /* don't try to import after the start of the Python finallization */
-    if (try_import && _Py_Finalizing == NULL) {
+    if (try_import && !_Py_IS_FINALIZING()) {
         warnings_module = PyImport_Import(warnings_str);
         if (warnings_module == NULL) {
             /* Fallback to the C implementation if we cannot get
@@ -90,10 +83,10 @@ get_once_registry(void)
     if (registry == NULL) {
         if (PyErr_Occurred())
             return NULL;
-        return _once_registry;
+        return _PyRuntime.warnings.once_registry;
     }
-    Py_DECREF(_once_registry);
-    _once_registry = registry;
+    Py_DECREF(_PyRuntime.warnings.once_registry);
+    _PyRuntime.warnings.once_registry = registry;
     return registry;
 }
 
@@ -108,11 +101,11 @@ get_default_action(void)
         if (PyErr_Occurred()) {
             return NULL;
         }
-        return _default_action;
+        return _PyRuntime.warnings.default_action;
     }
 
-    Py_DECREF(_default_action);
-    _default_action = default_action;
+    Py_DECREF(_PyRuntime.warnings.default_action);
+    _PyRuntime.warnings.default_action = default_action;
     return default_action;
 }
 
@@ -132,23 +125,24 @@ get_filter(PyObject *category, PyObject *text, Py_ssize_t lineno,
             return NULL;
     }
     else {
-        Py_DECREF(_filters);
-        _filters = warnings_filters;
+        Py_DECREF(_PyRuntime.warnings.filters);
+        _PyRuntime.warnings.filters = warnings_filters;
     }
 
-    if (_filters == NULL || !PyList_Check(_filters)) {
+    PyObject *filters = _PyRuntime.warnings.filters;
+    if (filters == NULL || !PyList_Check(filters)) {
         PyErr_SetString(PyExc_ValueError,
                         MODULE_NAME ".filters must be a list");
         return NULL;
     }
 
-    /* _filters could change while we are iterating over it. */
-    for (i = 0; i < PyList_GET_SIZE(_filters); i++) {
+    /* _PyRuntime.warnings.filters could change while we are iterating over it. */
+    for (i = 0; i < PyList_GET_SIZE(filters); i++) {
         PyObject *tmp_item, *action, *msg, *cat, *mod, *ln_obj;
         Py_ssize_t ln;
         int is_subclass, good_msg, good_mod;
 
-        tmp_item = PyList_GET_ITEM(_filters, i);
+        tmp_item = PyList_GET_ITEM(filters, i);
         if (!PyTuple_Check(tmp_item) || PyTuple_GET_SIZE(tmp_item) != 5) {
             PyErr_Format(PyExc_ValueError,
                          MODULE_NAME ".filters item %zd isn't a 5-tuple", i);
@@ -220,9 +214,9 @@ already_warned(PyObject *registry, PyObject *key, int should_set)
     version_obj = _PyDict_GetItemId(registry, &PyId_version);
     if (version_obj == NULL
         || !PyLong_CheckExact(version_obj)
-        || PyLong_AsLong(version_obj) != _filters_version) {
+        || PyLong_AsLong(version_obj) != _PyRuntime.warnings.filters_version) {
         PyDict_Clear(registry);
-        version_obj = PyLong_FromLong(_filters_version);
+        version_obj = PyLong_FromLong(_PyRuntime.warnings.filters_version);
         if (version_obj == NULL)
             return -1;
         if (_PyDict_SetItemId(registry, &PyId_version, version_obj) < 0) {
@@ -520,7 +514,7 @@ warn_explicit(PyObject *category, PyObject *message,
                 if (registry == NULL)
                     goto cleanup;
             }
-            /* _once_registry[(text, category)] = 1 */
+            /* _PyRuntime.warnings.once_registry[(text, category)] = 1 */
             rc = update_registry(registry, text, category, 0);
         }
         else if (_PyUnicode_EqualToASCIIString(action, "module")) {
@@ -910,7 +904,7 @@ warnings_warn_explicit(PyObject *self, PyObject *args, PyObject *kwds)
 static PyObject *
 warnings_filters_mutated(PyObject *self, PyObject *args)
 {
-    _filters_version++;
+    _PyRuntime.warnings.filters_version++;
     Py_RETURN_NONE;
 }
 
@@ -1160,7 +1154,8 @@ create_filter(PyObject *category, const char *action)
     }
 
     /* This assumes the line number is zero for now. */
-    return PyTuple_Pack(5, action_obj, Py_None, category, Py_None, _PyLong_Zero);
+    return PyTuple_Pack(5, action_obj, Py_None,
+                        category, Py_None, _PyLong_Zero);
 }
 
 static PyObject *
@@ -1228,33 +1223,35 @@ _PyWarnings_Init(void)
     if (m == NULL)
         return NULL;
 
-    if (_filters == NULL) {
-        _filters = init_filters();
-        if (_filters == NULL)
+    if (_PyRuntime.warnings.filters == NULL) {
+        _PyRuntime.warnings.filters = init_filters();
+        if (_PyRuntime.warnings.filters == NULL)
             return NULL;
     }
-    Py_INCREF(_filters);
-    if (PyModule_AddObject(m, "filters", _filters) < 0)
+    Py_INCREF(_PyRuntime.warnings.filters);
+    if (PyModule_AddObject(m, "filters", _PyRuntime.warnings.filters) < 0)
         return NULL;
 
-    if (_once_registry == NULL) {
-        _once_registry = PyDict_New();
-        if (_once_registry == NULL)
+    if (_PyRuntime.warnings.once_registry == NULL) {
+        _PyRuntime.warnings.once_registry = PyDict_New();
+        if (_PyRuntime.warnings.once_registry == NULL)
             return NULL;
     }
-    Py_INCREF(_once_registry);
-    if (PyModule_AddObject(m, "_onceregistry", _once_registry) < 0)
+    Py_INCREF(_PyRuntime.warnings.once_registry);
+    if (PyModule_AddObject(m, "_onceregistry",
+                           _PyRuntime.warnings.once_registry) < 0)
         return NULL;
 
-    if (_default_action == NULL) {
-        _default_action = PyUnicode_FromString("default");
-        if (_default_action == NULL)
+    if (_PyRuntime.warnings.default_action == NULL) {
+        _PyRuntime.warnings.default_action = PyUnicode_FromString("default");
+        if (_PyRuntime.warnings.default_action == NULL)
             return NULL;
     }
-    Py_INCREF(_default_action);
-    if (PyModule_AddObject(m, "_defaultaction", _default_action) < 0)
+    Py_INCREF(_PyRuntime.warnings.default_action);
+    if (PyModule_AddObject(m, "_defaultaction",
+                           _PyRuntime.warnings.default_action) < 0)
         return NULL;
 
-    _filters_version = 0;
+    _PyRuntime.warnings.filters_version = 0;
     return m;
 }

Python/condvar.h

@@ -37,27 +37,16 @@
  *    Condition Variable.
  */
 
-#ifndef _CONDVAR_H_
-#define _CONDVAR_H_
+#ifndef _CONDVAR_IMPL_H_
+#define _CONDVAR_IMPL_H_
 
 #include "Python.h"
-
-#ifndef _POSIX_THREADS
-/* This means pthreads are not implemented in libc headers, hence the macro
-   not present in unistd.h. But they still can be implemented as an external
-   library (e.g. gnu pth in pthread emulation) */
-# ifdef HAVE_PTHREAD_H
-#  include <pthread.h> /* _POSIX_THREADS */
-# endif
-#endif
+#include "internal/_condvar.h"
 
 #ifdef _POSIX_THREADS
 /*
  * POSIX support
  */
-#define Py_HAVE_CONDVAR
-
-#include <pthread.h>
 
 #define PyCOND_ADD_MICROSECONDS(tv, interval) \
 do { /* TODO: add overflow and truncation checks */ \
@@ -74,13 +63,11 @@ do { /* TODO: add overflow and truncation checks */ \
 #endif
 
 /* The following functions return 0 on success, nonzero on error */
-#define PyMUTEX_T pthread_mutex_t
 #define PyMUTEX_INIT(mut)       pthread_mutex_init((mut), NULL)
 #define PyMUTEX_FINI(mut)       pthread_mutex_destroy(mut)
 #define PyMUTEX_LOCK(mut)       pthread_mutex_lock(mut)
 #define PyMUTEX_UNLOCK(mut)     pthread_mutex_unlock(mut)
 
-#define PyCOND_T pthread_cond_t
 #define PyCOND_INIT(cond)       pthread_cond_init((cond), NULL)
 #define PyCOND_FINI(cond)       pthread_cond_destroy(cond)
 #define PyCOND_SIGNAL(cond)     pthread_cond_signal(cond)
@@ -116,45 +103,11 @@ PyCOND_TIMEDWAIT(PyCOND_T *cond, PyMUTEX_T *mut, long long us)
  * Emulated condition variables ones that work with XP and later, plus
  * example native support on VISTA and onwards.
  */
-#define Py_HAVE_CONDVAR
-
-
-/* include windows if it hasn't been done before */
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-
-/* options */
-/* non-emulated condition variables are provided for those that want
- * to target Windows Vista.  Modify this macro to enable them.
- */
-#ifndef _PY_EMULATED_WIN_CV
-#define _PY_EMULATED_WIN_CV 1  /* use emulated condition variables */
-#endif
-
-/* fall back to emulation if not targeting Vista */
-#if !defined NTDDI_VISTA || NTDDI_VERSION < NTDDI_VISTA
-#undef _PY_EMULATED_WIN_CV
-#define _PY_EMULATED_WIN_CV 1
-#endif
-
 
 #if _PY_EMULATED_WIN_CV
 
 /* The mutex is a CriticalSection object and
    The condition variables is emulated with the help of a semaphore.
-   Semaphores are available on Windows XP (2003 server) and later.
-   We use a Semaphore rather than an auto-reset event, because although
-   an auto-resent event might appear to solve the lost-wakeup bug (race
-   condition between releasing the outer lock and waiting) because it
-   maintains state even though a wait hasn't happened, there is still
-   a lost wakeup problem if more than one thread are interrupted in the
-   critical place.  A semaphore solves that, because its state is counted,
-   not Boolean.
-   Because it is ok to signal a condition variable with no one
-   waiting, we need to keep track of the number of
-   waiting threads.  Otherwise, the semaphore's state could rise
-   without bound.  This also helps reduce the number of "spurious wakeups"
-   that would otherwise happen.
 
    This implementation still has the problem that the threads woken
    with a "signal" aren't necessarily those that are already
@@ -168,8 +121,6 @@ PyCOND_TIMEDWAIT(PyCOND_T *cond, PyMUTEX_T *mut, long long us)
    http://www.cse.wustl.edu/~schmidt/win32-cv-1.html
 */
 
-typedef CRITICAL_SECTION PyMUTEX_T;
-
 Py_LOCAL_INLINE(int)
 PyMUTEX_INIT(PyMUTEX_T *cs)
 {
@@ -198,15 +149,6 @@ PyMUTEX_UNLOCK(PyMUTEX_T *cs)
     return 0;
 }
 
-/* The ConditionVariable object.  From XP onwards it is easily emulated with
- * a Semaphore
- */
-
-typedef struct _PyCOND_T
-{
-    HANDLE sem;
-    int waiting; /* to allow PyCOND_SIGNAL to be a no-op */
-} PyCOND_T;
 
 Py_LOCAL_INLINE(int)
 PyCOND_INIT(PyCOND_T *cv)
@@ -304,12 +246,7 @@ PyCOND_BROADCAST(PyCOND_T *cv)
     return 0;
 }
 
-#else
-
-/* Use native Win7 primitives if build target is Win7 or higher */
-
-/* SRWLOCK is faster and better than CriticalSection */
-typedef SRWLOCK PyMUTEX_T;
+#else /* !_PY_EMULATED_WIN_CV */
 
 Py_LOCAL_INLINE(int)
 PyMUTEX_INIT(PyMUTEX_T *cs)
@@ -339,8 +276,6 @@ PyMUTEX_UNLOCK(PyMUTEX_T *cs)
 }
 
 
-typedef CONDITION_VARIABLE  PyCOND_T;
-
 Py_LOCAL_INLINE(int)
 PyCOND_INIT(PyCOND_T *cv)
 {
@@ -387,4 +322,4 @@ PyCOND_BROADCAST(PyCOND_T *cv)
 
 #endif /* _POSIX_THREADS, NT_THREADS */
 
-#endif /* _CONDVAR_H_ */
+#endif /* _CONDVAR_IMPL_H_ */

Python/pylifecycle.c

@@ -77,6 +77,30 @@ extern void _PyGILState_Init(PyInterpreterState *, PyThreadState *);
 extern void _PyGILState_Fini(void);
 #endif /* WITH_THREAD */
 
+_PyRuntimeState _PyRuntime = {};
+
+void
+_PyRuntime_Initialize(void)
+{
+    /* XXX We only initialize once in the process, which aligns with
+       the static initialization of the former globals now found in
+       _PyRuntime.  However, _PyRuntime *should* be initialized with
+       every Py_Initialize() call, but doing so breaks the runtime.
+       This is because the runtime state is not properly finalized
+       currently. */
+    static int initialized = 0;
+    if (initialized)
+        return;
+    initialized = 1;
+    _PyRuntimeState_Init(&_PyRuntime);
+}
+
+void
+_PyRuntime_Finalize(void)
+{
+    _PyRuntimeState_Fini(&_PyRuntime);
+}
+
 /* Global configuration variable declarations are in pydebug.h */
 /* XXX (ncoghlan): move those declarations to pylifecycle.h? */
 int Py_DebugFlag; /* Needed by parser.c */
@@ -100,8 +124,6 @@ int Py_LegacyWindowsFSEncodingFlag = 0; /* Uses mbcs instead of utf-8 */
 int Py_LegacyWindowsStdioFlag = 0; /* Uses FileIO instead of WindowsConsoleIO */
 #endif
 
-PyThreadState *_Py_Finalizing = NULL;
-
 /* Hack to force loading of object files */
 int (*_PyOS_mystrnicmp_hack)(const char *, const char *, Py_ssize_t) = \
     PyOS_mystrnicmp; /* Python/pystrcmp.o */
@@ -119,19 +141,17 @@ PyModule_GetWarningsModule(void)
  *
  * Can be called prior to Py_Initialize.
  */
-int _Py_CoreInitialized = 0;
-int _Py_Initialized = 0;
 
 int
 _Py_IsCoreInitialized(void)
 {
-    return _Py_CoreInitialized;
+    return _PyRuntime.core_initialized;
 }
 
 int
 Py_IsInitialized(void)
 {
-    return _Py_Initialized;
+    return _PyRuntime.initialized;
 }
 
 /* Helper to allow an embedding application to override the normal
@@ -544,14 +564,16 @@ void _Py_InitializeCore(const _PyCoreConfig *config)
     _PyCoreConfig core_config = _PyCoreConfig_INIT;
     _PyMainInterpreterConfig preinit_config = _PyMainInterpreterConfig_INIT;
 
+    _PyRuntime_Initialize();
+
     if (config != NULL) {
         core_config = *config;
     }
 
-    if (_Py_Initialized) {
+    if (_PyRuntime.initialized) {
         Py_FatalError("Py_InitializeCore: main interpreter already initialized");
     }
-    if (_Py_CoreInitialized) {
+    if (_PyRuntime.core_initialized) {
         Py_FatalError("Py_InitializeCore: runtime core already initialized");
     }
 
@@ -564,7 +586,14 @@ void _Py_InitializeCore(const _PyCoreConfig *config)
      * threads still hanging around from a previous Py_Initialize/Finalize
      * pair :(
      */
-    _Py_Finalizing = NULL;
+    _PyRuntime.finalizing = NULL;
+
+    if (_PyMem_SetupAllocators(core_config.allocator) < 0) {
+        fprintf(stderr,
+            "Error in PYTHONMALLOC: unknown allocator \"%s\"!\n",
+            core_config.allocator);
+        exit(1);
+    }
 
 #ifdef __ANDROID__
     /* Passing "" to setlocale() on Android requests the C locale rather
@@ -606,7 +635,7 @@ void _Py_InitializeCore(const _PyCoreConfig *config)
         Py_HashRandomizationFlag = 1;
     }
 
-    _PyInterpreterState_Init();
+    _PyInterpreterState_Enable(&_PyRuntime);
     interp = PyInterpreterState_New();
     if (interp == NULL)
         Py_FatalError("Py_InitializeCore: can't make main interpreter");
@@ -698,7 +727,7 @@ void _Py_InitializeCore(const _PyCoreConfig *config)
     }
 
     /* Only when we get here is the runtime core fully initialized */
-    _Py_CoreInitialized = 1;
+    _PyRuntime.core_initialized = 1;
 }
 
 /* Read configuration settings from standard locations
@@ -739,10 +768,10 @@ int _Py_InitializeMainInterpreter(const _PyMainInterpreterConfig *config)
     PyInterpreterState *interp;
     PyThreadState *tstate;
 
-    if (!_Py_CoreInitialized) {
+    if (!_PyRuntime.core_initialized) {
         Py_FatalError("Py_InitializeMainInterpreter: runtime core not initialized");
     }
-    if (_Py_Initialized) {
+    if (_PyRuntime.initialized) {
         Py_FatalError("Py_InitializeMainInterpreter: main interpreter already initialized");
     }
 
@@ -763,7 +792,7 @@ int _Py_InitializeMainInterpreter(const _PyMainInterpreterConfig *config)
          * This means anything which needs support from extension modules
          * or pure Python code in the standard library won't work.
          */
-        _Py_Initialized = 1;
+        _PyRuntime.initialized = 1;
         return 0;
     }
     /* TODO: Report exceptions rather than fatal errors below here */
@@ -808,7 +837,7 @@ int _Py_InitializeMainInterpreter(const _PyMainInterpreterConfig *config)
         Py_XDECREF(warnings_module);
     }
 
-    _Py_Initialized = 1;
+    _PyRuntime.initialized = 1;
 
     if (!Py_NoSiteFlag)
         initsite(); /* Module site */
@@ -924,7 +953,7 @@ Py_FinalizeEx(void)
     PyThreadState *tstate;
     int status = 0;
 
-    if (!_Py_Initialized)
+    if (!_PyRuntime.initialized)
         return status;
 
     wait_for_thread_shutdown();
@@ -946,9 +975,9 @@ Py_FinalizeEx(void)
 
     /* Remaining threads (e.g. daemon threads) will automatically exit
        after taking the GIL (in PyEval_RestoreThread()). */
-    _Py_Finalizing = tstate;
-    _Py_Initialized = 0;
-    _Py_CoreInitialized = 0;
+    _PyRuntime.finalizing = tstate;
+    _PyRuntime.initialized = 0;
+    _PyRuntime.core_initialized = 0;
 
     /* Flush sys.stdout and sys.stderr */
     if (flush_std_files() < 0) {
@@ -1110,6 +1139,7 @@ Py_FinalizeEx(void)
 #endif
 
     call_ll_exitfuncs();
+    _PyRuntime_Finalize();
     return status;
 }
 
@@ -1139,7 +1169,7 @@ Py_NewInterpreter(void)
     PyThreadState *tstate, *save_tstate;
     PyObject *bimod, *sysmod;
 
-    if (!_Py_Initialized)
+    if (!_PyRuntime.initialized)
         Py_FatalError("Py_NewInterpreter: call Py_Initialize first");
 
 #ifdef WITH_THREAD
@@ -1854,20 +1884,19 @@ exit:
 #  include "pythread.h"
 #endif
 
-static void (*pyexitfunc)(void) = NULL;
 /* For the atexit module. */
 void _Py_PyAtExit(void (*func)(void))
 {
-    pyexitfunc = func;
+    _PyRuntime.pyexitfunc = func;
 }
 
 static void
 call_py_exitfuncs(void)
 {
-    if (pyexitfunc == NULL)
+    if (_PyRuntime.pyexitfunc == NULL)
         return;
 
-    (*pyexitfunc)();
+    (*_PyRuntime.pyexitfunc)();
     PyErr_Clear();
 }
 
@@ -1900,22 +1929,19 @@ wait_for_thread_shutdown(void)
 }
 
 #define NEXITFUNCS 32
-static void (*exitfuncs[NEXITFUNCS])(void);
-static int nexitfuncs = 0;
-
 int Py_AtExit(void (*func)(void))
 {
-    if (nexitfuncs >= NEXITFUNCS)
+    if (_PyRuntime.nexitfuncs >= NEXITFUNCS)
         return -1;
-    exitfuncs[nexitfuncs++] = func;
+    _PyRuntime.exitfuncs[_PyRuntime.nexitfuncs++] = func;
     return 0;
 }
 
 static void
 call_ll_exitfuncs(void)
 {
-    while (nexitfuncs > 0)
-        (*exitfuncs[--nexitfuncs])();
+    while (_PyRuntime.nexitfuncs > 0)
+        (*_PyRuntime.exitfuncs[--_PyRuntime.nexitfuncs])();
 
     fflush(stdout);
     fflush(stderr);

Python/sysmodule.c

@@ -519,8 +519,6 @@ Return the profiling function set with sys.setprofile.\n\
 See the profiler chapter in the library manual."
 );
 
-static int _check_interval = 100;
-
 static PyObject *
 sys_setcheckinterval(PyObject *self, PyObject *args)
 {
@@ -529,7 +527,8 @@ sys_setcheckinterval(PyObject *self, PyObject *args)
                      "are deprecated.  Use sys.setswitchinterval() "
                      "instead.", 1) < 0)
         return NULL;
-    if (!PyArg_ParseTuple(args, "i:setcheckinterval", &_check_interval))
+    PyInterpreterState *interp = PyThreadState_GET()->interp;
+    if (!PyArg_ParseTuple(args, "i:setcheckinterval", &interp->check_interval))
         return NULL;
     Py_RETURN_NONE;
 }
@@ -549,7 +548,8 @@ sys_getcheckinterval(PyObject *self, PyObject *args)
                      "are deprecated.  Use sys.getswitchinterval() "
                      "instead.", 1) < 0)
         return NULL;
-    return PyLong_FromLong(_check_interval);
+    PyInterpreterState *interp = PyThreadState_GET()->interp;
+    return PyLong_FromLong(interp->check_interval);
 }
 
 PyDoc_STRVAR(getcheckinterval_doc,
@@ -1339,7 +1339,7 @@ Clear the internal type lookup cache.");
 static PyObject *
 sys_is_finalizing(PyObject* self, PyObject* args)
 {
-    return PyBool_FromLong(_Py_Finalizing != NULL);
+    return PyBool_FromLong(_Py_IS_FINALIZING());
 }
 
 PyDoc_STRVAR(is_finalizing_doc,
@@ -1479,11 +1479,24 @@ list_builtin_module_names(void)
     return list;
 }
 
-static PyObject *warnoptions = NULL;
+static PyObject *
+get_warnoptions(void)
+{
+    PyObject *warnoptions = PyThreadState_GET()->interp->warnoptions;
+    if (warnoptions == NULL || !PyList_Check(warnoptions)) {
+        Py_XDECREF(warnoptions);
+        warnoptions = PyList_New(0);
+        if (warnoptions == NULL)
+            return NULL;
+        PyThreadState_GET()->interp->warnoptions = warnoptions;
+    }
+    return warnoptions;
+}
 
 void
 PySys_ResetWarnOptions(void)
 {
+    PyObject *warnoptions = PyThreadState_GET()->interp->warnoptions;
     if (warnoptions == NULL || !PyList_Check(warnoptions))
         return;
     PyList_SetSlice(warnoptions, 0, PyList_GET_SIZE(warnoptions), NULL);
@@ -1492,12 +1505,9 @@ PySys_ResetWarnOptions(void)
 void
 PySys_AddWarnOptionUnicode(PyObject *unicode)
 {
-    if (warnoptions == NULL || !PyList_Check(warnoptions)) {
-        Py_XDECREF(warnoptions);
-        warnoptions = PyList_New(0);
-        if (warnoptions == NULL)
-            return;
-    }
+    PyObject *warnoptions = get_warnoptions();
+    if (warnoptions == NULL)
+        return;
     PyList_Append(warnoptions, unicode);
 }
 
@@ -1515,17 +1525,20 @@ PySys_AddWarnOption(const wchar_t *s)
 int
 PySys_HasWarnOptions(void)
 {
+    PyObject *warnoptions = PyThreadState_GET()->interp->warnoptions;
     return (warnoptions != NULL && (PyList_Size(warnoptions) > 0)) ? 1 : 0;
 }
 
-static PyObject *xoptions = NULL;
-
 static PyObject *
 get_xoptions(void)
 {
+    PyObject *xoptions = PyThreadState_GET()->interp->xoptions;
     if (xoptions == NULL || !PyDict_Check(xoptions)) {
         Py_XDECREF(xoptions);
         xoptions = PyDict_New();
+        if (xoptions == NULL)
+            return NULL;
+        PyThreadState_GET()->interp->xoptions = xoptions;
     }
     return xoptions;
 }
@@ -2130,17 +2143,15 @@ _PySys_EndInit(PyObject *sysdict)
     SET_SYS_FROM_STRING_INT_RESULT("base_exec_prefix",
                         PyUnicode_FromWideChar(Py_GetExecPrefix(), -1));
 
-    if (warnoptions == NULL) {
-        warnoptions = PyList_New(0);
-        if (warnoptions == NULL)
-            return -1;
-    }
-
-    SET_SYS_FROM_STRING_INT_RESULT("warnoptions",
-                                   PyList_GetSlice(warnoptions,
-                                                   0, Py_SIZE(warnoptions)));
+    PyObject *warnoptions = get_warnoptions();
+    if (warnoptions == NULL)
+        return -1;
+    SET_SYS_FROM_STRING_BORROW_INT_RESULT("warnoptions", warnoptions);
 
-    SET_SYS_FROM_STRING_BORROW_INT_RESULT("_xoptions", get_xoptions());
+    PyObject *xoptions = get_xoptions();
+    if (xoptions == NULL)
+        return -1;
+    SET_SYS_FROM_STRING_BORROW_INT_RESULT("_xoptions", xoptions);
 
     if (PyErr_Occurred())
         return -1;

Python/thread.c

@@ -76,11 +76,6 @@ PyThread_init_thread(void)
     PyThread__init_thread();
 }
 
-/* Support for runtime thread stack size tuning.
-   A value of 0 means using the platform's default stack size
-   or the size specified by the THREAD_STACK_SIZE macro. */
-static size_t _pythread_stacksize = 0;
-
 #if defined(_POSIX_THREADS)
 #   define PYTHREAD_NAME "pthread"
 #   include "thread_pthread.h"
@@ -96,7 +91,7 @@ static size_t _pythread_stacksize = 0;
 size_t
 PyThread_get_stacksize(void)
 {
-    return _pythread_stacksize;
+    return PyThreadState_GET()->interp->pythread_stacksize;
 }
 
 /* Only platforms defining a THREAD_SET_STACKSIZE() macro

Python/thread_nt.h

@@ -189,9 +189,10 @@ PyThread_start_new_thread(void (*func)(void *), void *arg)
         return PYTHREAD_INVALID_THREAD_ID;
     obj->func = func;
     obj->arg = arg;
+    PyThreadState *tstate = PyThreadState_GET();
+    size_t stacksize = tstate ? tstate->interp->pythread_stacksize : 0;
     hThread = (HANDLE)_beginthreadex(0,
-                      Py_SAFE_DOWNCAST(_pythread_stacksize,
-                                       Py_ssize_t, unsigned int),
+                      Py_SAFE_DOWNCAST(stacksize, Py_ssize_t, unsigned int),
                       bootstrap, obj,
                       0, &threadID);
     if (hThread == 0) {
@@ -332,13 +333,13 @@ _pythread_nt_set_stacksize(size_t size)
 {
     /* set to default */
     if (size == 0) {
-        _pythread_stacksize = 0;
+        PyThreadState_GET()->interp->pythread_stacksize = 0;
         return 0;
     }
 
     /* valid range? */
     if (size >= THREAD_MIN_STACKSIZE && size < THREAD_MAX_STACKSIZE) {
-        _pythread_stacksize = size;
+        PyThreadState_GET()->interp->pythread_stacksize = size;
         return 0;
     }
 

Python/thread_pthread.h

@@ -205,8 +205,9 @@ PyThread_start_new_thread(void (*func)(void *), void *arg)
         return PYTHREAD_INVALID_THREAD_ID;
 #endif
 #if defined(THREAD_STACK_SIZE)
-    tss = (_pythread_stacksize != 0) ? _pythread_stacksize
-                                     : THREAD_STACK_SIZE;
+    PyThreadState *tstate = PyThreadState_GET();
+    size_t stacksize = tstate ? tstate->interp->pythread_stacksize : 0;
+    tss = (stacksize != 0) ? stacksize : THREAD_STACK_SIZE;
     if (tss != 0) {
         if (pthread_attr_setstacksize(&attrs, tss) != 0) {
             pthread_attr_destroy(&attrs);
@@ -578,7 +579,7 @@ _pythread_pthread_set_stacksize(size_t size)
 
     /* set to default */
     if (size == 0) {
-        _pythread_stacksize = 0;
+        PyThreadState_GET()->interp->pythread_stacksize = 0;
         return 0;
     }
 
@@ -595,7 +596,7 @@ _pythread_pthread_set_stacksize(size_t size)
             rc = pthread_attr_setstacksize(&attrs, size);
             pthread_attr_destroy(&attrs);
             if (rc == 0) {
-                _pythread_stacksize = size;
+                PyThreadState_GET()->interp->pythread_stacksize = size;
                 return 0;
             }
         }

Tools/c-globals/README

+#######################################
+# C Globals and CPython Runtime State.
+
+CPython's C code makes extensive use of global variables.  Each global
+falls into one of several categories:
+
+* (effectively) constants (incl. static types)
+* globals used exclusively in main or in the REPL
+* freelists, caches, and counters
+* process-global state
+* module state
+* Python runtime state
+
+The ignored-globals.txt file is organized similarly.  Of the different
+categories, the last two are problematic and generally should not exist
+in the codebase.
+
+Globals that hold module state (i.e. in Modules/*.c) cause problems
+when multiple interpreters are in use.  For more info, see PEP 3121,
+which addresses the situation for extension modules in general.
+
+Globals in the last category should be avoided as well.  The problem
+isn't with the Python runtime having state.  Rather, the problem is with
+that state being spread thoughout the codebase in dozens of individual
+globals.  Unlike the other globals, the runtime state represents a set
+of values that are constantly shifting in a complex way.  When they are
+spread out it's harder to get a clear picture of what the runtime
+involves.  Furthermore, when they are spread out it complicates efforts
+that change the runtime.
+
+Consequently, the globals for Python's runtime state have been
+consolidated under a single top-level _PyRuntime global. No new globals
+should be added for runtime state.  Instead, they should be added to
+_PyRuntimeState or one of its sub-structs.  The check-c-globals script
+should be run to ensure that no new globals have been added:
+
+  python3 Tools/c-globals/check-c-globals.py
+
+If it reports any globals then they should be resolved.  If the globals
+are runtime state then they should be folded into _PyRuntimeState.
+Otherwise they should be added to ignored-globals.txt.