bpo-31370: Remove support for threads-less builds (#3385)

* Remove Setup.config
* Always define WITH_THREAD for compatibility.

Modules/_tracemalloc.c

@@ -51,7 +51,7 @@ static struct {
     int use_domain;
 } tracemalloc_config = {TRACEMALLOC_NOT_INITIALIZED, 0, 1, 0};
 
-#if defined(TRACE_RAW_MALLOC) && defined(WITH_THREAD)
+#if defined(TRACE_RAW_MALLOC)
 /* This lock is needed because tracemalloc_free() is called without
    the GIL held from PyMem_RawFree(). It cannot acquire the lock because it
    would introduce a deadlock in PyThreadState_DeleteCurrent(). */
@@ -164,7 +164,7 @@ tracemalloc_error(const char *format, ...)
 #endif
 
 
-#if defined(WITH_THREAD) && defined(TRACE_RAW_MALLOC)
+#if defined(TRACE_RAW_MALLOC)
 #define REENTRANT_THREADLOCAL
 
 /* If your OS does not provide native thread local storage, you can implement
@@ -212,8 +212,7 @@ set_reentrant(int reentrant)
 
 #else
 
-/* WITH_THREAD not defined: Python compiled without threads,
-   or TRACE_RAW_MALLOC not defined: variable protected by the GIL */
+/* TRACE_RAW_MALLOC not defined: variable protected by the GIL */
 static int tracemalloc_reentrant = 0;
 
 static int
@@ -455,11 +454,7 @@ traceback_get_frames(traceback_t *traceback)
     PyThreadState *tstate;
     PyFrameObject *pyframe;
 
-#ifdef WITH_THREAD
     tstate = PyGILState_GetThisThreadState();
-#else
-    tstate = PyThreadState_Get();
-#endif
     if (tstate == NULL) {
 #ifdef TRACE_DEBUG
         tracemalloc_error("failed to get the current thread state");
@@ -483,9 +478,7 @@ traceback_new(void)
     traceback_t *traceback;
     _Py_hashtable_entry_t *entry;
 
-#ifdef WITH_THREAD
     assert(PyGILState_Check());
-#endif
 
     /* get frames */
     traceback = tracemalloc_traceback;
@@ -848,9 +841,7 @@ tracemalloc_realloc_gil(void *ctx, void *ptr, size_t new_size)
 static void*
 tracemalloc_raw_alloc(int use_calloc, void *ctx, size_t nelem, size_t elsize)
 {
-#ifdef WITH_THREAD
     PyGILState_STATE gil_state;
-#endif
     void *ptr;
 
     if (get_reentrant()) {
@@ -866,13 +857,9 @@ tracemalloc_raw_alloc(int use_calloc, void *ctx, size_t nelem, size_t elsize)
        disabled. */
     set_reentrant(1);
 
-#ifdef WITH_THREAD
     gil_state = PyGILState_Ensure();
     ptr = tracemalloc_alloc(use_calloc, ctx, nelem, elsize);
     PyGILState_Release(gil_state);
-#else
-    ptr = tracemalloc_alloc(use_calloc, ctx, nelem, elsize);
-#endif
 
     set_reentrant(0);
     return ptr;
@@ -896,9 +883,7 @@ tracemalloc_raw_calloc(void *ctx, size_t nelem, size_t elsize)
 static void*
 tracemalloc_raw_realloc(void *ctx, void *ptr, size_t new_size)
 {
-#ifdef WITH_THREAD
     PyGILState_STATE gil_state;
-#endif
     void *ptr2;
 
     if (get_reentrant()) {
@@ -920,13 +905,9 @@ tracemalloc_raw_realloc(void *ctx, void *ptr, size_t new_size)
        not disabled. */
     set_reentrant(1);
 
-#ifdef WITH_THREAD
     gil_state = PyGILState_Ensure();
     ptr2 = tracemalloc_realloc(ctx, ptr, new_size);
     PyGILState_Release(gil_state);
-#else
-    ptr2 = tracemalloc_realloc(ctx, ptr, new_size);
-#endif
 
     set_reentrant(0);
     return ptr2;
@@ -962,10 +943,8 @@ traceback_free_traceback(_Py_hashtable_t *ht, _Py_hashtable_entry_t *entry,
 static void
 tracemalloc_clear_traces(void)
 {
-#ifdef WITH_THREAD
     /* The GIL protects variables againt concurrent access */
     assert(PyGILState_Check());
-#endif
 
     TABLES_LOCK();
     _Py_hashtable_clear(tracemalloc_traces);
@@ -1007,7 +986,7 @@ tracemalloc_init(void)
     }
 #endif
 
-#if defined(WITH_THREAD) && defined(TRACE_RAW_MALLOC)
+#if defined(TRACE_RAW_MALLOC)
     if (tables_lock == NULL) {
         tables_lock = PyThread_allocate_lock();
         if (tables_lock == NULL) {
@@ -1074,7 +1053,7 @@ tracemalloc_deinit(void)
     _Py_hashtable_destroy(tracemalloc_filenames);
     _Py_hashtable_destroy(tracemalloc_traces);
 
-#if defined(WITH_THREAD) && defined(TRACE_RAW_MALLOC)
+#if defined(TRACE_RAW_MALLOC)
     if (tables_lock != NULL) {
         PyThread_free_lock(tables_lock);
         tables_lock = NULL;
@@ -1723,9 +1702,7 @@ _PyTraceMalloc_Init(void)
     char *p;
     int nframe;
 
-#ifdef WITH_THREAD
     assert(PyGILState_Check());
-#endif
 
     if ((p = Py_GETENV("PYTHONTRACEMALLOC")) && *p != '\0') {
         char *endptr = p;
@@ -1778,9 +1755,7 @@ _PyTraceMalloc_Init(void)
 void
 _PyTraceMalloc_Fini(void)
 {
-#ifdef WITH_THREAD
     assert(PyGILState_Check());
-#endif
     tracemalloc_deinit();
 }
 
@@ -1789,26 +1764,20 @@ PyTraceMalloc_Track(unsigned int domain, uintptr_t ptr,
                     size_t size)
 {
     int res;
-#ifdef WITH_THREAD
     PyGILState_STATE gil_state;
-#endif
 
     if (!tracemalloc_config.tracing) {
         /* tracemalloc is not tracing: do nothing */
         return -2;
     }
 
-#ifdef WITH_THREAD
     gil_state = PyGILState_Ensure();
-#endif
 
     TABLES_LOCK();
     res = tracemalloc_add_trace(domain, ptr, size);
     TABLES_UNLOCK();
 
-#ifdef WITH_THREAD
     PyGILState_Release(gil_state);
-#endif
     return res;
 }