gh-109693: Use pyatomic.h for signal module (gh-110480)

Include/internal/pycore_signal.h

@@ -10,7 +10,6 @@ extern "C" {
 #  error "this header requires Py_BUILD_CORE define"
 #endif
 
-#include "pycore_atomic.h"        // _Py_atomic_address
 #include <signal.h>               // NSIG
 
 
@@ -38,12 +37,10 @@ PyAPI_FUNC(void) _Py_RestoreSignals(void);
 #define INVALID_FD (-1)
 
 struct _signals_runtime_state {
-    volatile struct {
+    struct {
-        _Py_atomic_int tripped;
+        // tripped and func should be accessed using atomic ops.
-        /* func is atomic to ensure that PyErr_SetInterrupt is async-signal-safe
+        int tripped;
-         * (even though it would probably be otherwise, anyway).
+        PyObject* func;
-         */
-        _Py_atomic_address func;
     } handlers[Py_NSIG];
 
     volatile struct {
@@ -63,8 +60,9 @@ struct _signals_runtime_state {
 #endif
     } wakeup;
 
-    /* Speed up sigcheck() when none tripped */
+    /* Speed up sigcheck() when none tripped.
-    _Py_atomic_int is_tripped;
+       is_tripped should be accessed using atomic ops. */
+    int is_tripped;
 
     /* These objects necessarily belong to the main interpreter. */
     PyObject *default_handler;

Modules/signalmodule.c

@@ -4,7 +4,6 @@
 /* XXX Signals should be recorded per thread, now we have thread state. */
 
 #include "Python.h"
-#include "pycore_atomic.h"        // _Py_atomic_int
 #include "pycore_call.h"          // _PyObject_Call()
 #include "pycore_ceval.h"         // _PyEval_SignalReceived()
 #include "pycore_emscripten_signal.h"  // _Py_CHECK_EMSCRIPTEN_SIGNALS
@@ -124,13 +123,15 @@ typedef struct {
 Py_LOCAL_INLINE(PyObject *)
 get_handler(int i)
 {
-    return (PyObject *)_Py_atomic_load(&Handlers[i].func);
+    return (PyObject *)_Py_atomic_load_ptr(&Handlers[i].func);
 }
 
 Py_LOCAL_INLINE(void)
 set_handler(int i, PyObject* func)
 {
-    _Py_atomic_store(&Handlers[i].func, (uintptr_t)func);
+    /* Store func with atomic operation to ensure
+       that PyErr_SetInterrupt is async-signal-safe. */
+    _Py_atomic_store_ptr(&Handlers[i].func, func);
 }
 
 
@@ -267,11 +268,11 @@ report_wakeup_send_error(void* data)
 static void
 trip_signal(int sig_num)
 {
-    _Py_atomic_store_relaxed(&Handlers[sig_num].tripped, 1);
+    _Py_atomic_store_int(&Handlers[sig_num].tripped, 1);
 
     /* Set is_tripped after setting .tripped, as it gets
        cleared in PyErr_CheckSignals() before .tripped. */
-    _Py_atomic_store(&is_tripped, 1);
+    _Py_atomic_store_int(&is_tripped, 1);
 
     /* Signals are always handled by the main interpreter */
     PyInterpreterState *interp = _PyInterpreterState_Main();
@@ -1731,7 +1732,7 @@ _PySignal_Fini(void)
     // Restore default signals and clear handlers
     for (int signum = 1; signum < Py_NSIG; signum++) {
         PyObject *func = get_handler(signum);
-        _Py_atomic_store_relaxed(&Handlers[signum].tripped, 0);
+        _Py_atomic_store_int_relaxed(&Handlers[signum].tripped, 0);
         set_handler(signum, NULL);
         if (func != NULL
             && func != Py_None
@@ -1785,7 +1786,7 @@ int
 _PyErr_CheckSignalsTstate(PyThreadState *tstate)
 {
     _Py_CHECK_EMSCRIPTEN_SIGNALS();
-    if (!_Py_atomic_load(&is_tripped)) {
+    if (!_Py_atomic_load_int(&is_tripped)) {
         return 0;
     }
 
@@ -1803,15 +1804,15 @@ _PyErr_CheckSignalsTstate(PyThreadState *tstate)
      *       we receive a signal i after we zero is_tripped and before we
      *       check Handlers[i].tripped.
      */
-    _Py_atomic_store(&is_tripped, 0);
+    _Py_atomic_store_int(&is_tripped, 0);
 
     _PyInterpreterFrame *frame = _PyThreadState_GetFrame(tstate);
     signal_state_t *state = &signal_global_state;
     for (int i = 1; i < Py_NSIG; i++) {
-        if (!_Py_atomic_load_relaxed(&Handlers[i].tripped)) {
+        if (!_Py_atomic_load_int_relaxed(&Handlers[i].tripped)) {
             continue;
         }
-        _Py_atomic_store_relaxed(&Handlers[i].tripped, 0);
+        _Py_atomic_store_int_relaxed(&Handlers[i].tripped, 0);
 
         /* Signal handlers can be modified while a signal is received,
          * and therefore the fact that trip_signal() or PyErr_SetInterrupt()
@@ -1857,7 +1858,7 @@ _PyErr_CheckSignalsTstate(PyThreadState *tstate)
         }
         if (!result) {
             /* On error, re-schedule a call to _PyErr_CheckSignalsTstate() */
-            _Py_atomic_store(&is_tripped, 1);
+            _Py_atomic_store_int(&is_tripped, 1);
             return -1;
         }
 
@@ -1975,7 +1976,7 @@ _PySignal_Init(int install_signal_handlers)
 #endif
 
     for (int signum = 1; signum < Py_NSIG; signum++) {
-        _Py_atomic_store_relaxed(&Handlers[signum].tripped, 0);
+        _Py_atomic_store_int_relaxed(&Handlers[signum].tripped, 0);
     }
 
     if (install_signal_handlers) {
@@ -1997,11 +1998,11 @@ _PyOS_InterruptOccurred(PyThreadState *tstate)
         return 0;
     }
 
-    if (!_Py_atomic_load_relaxed(&Handlers[SIGINT].tripped)) {
+    if (!_Py_atomic_load_int_relaxed(&Handlers[SIGINT].tripped)) {
         return 0;
     }
 
-    _Py_atomic_store_relaxed(&Handlers[SIGINT].tripped, 0);
+    _Py_atomic_store_int_relaxed(&Handlers[SIGINT].tripped, 0);
     return 1;
 }
 
@@ -2019,13 +2020,13 @@ PyOS_InterruptOccurred(void)
 static void
 _clear_pending_signals(void)
 {
-    if (!_Py_atomic_load(&is_tripped)) {
+    if (!_Py_atomic_load_int(&is_tripped)) {
         return;
     }
 
-    _Py_atomic_store(&is_tripped, 0);
+    _Py_atomic_store_int(&is_tripped, 0);
     for (int i = 1; i < Py_NSIG; ++i) {
-        _Py_atomic_store_relaxed(&Handlers[i].tripped, 0);
+        _Py_atomic_store_int_relaxed(&Handlers[i].tripped, 0);
     }
 }
 

Python/ceval_gil.c

@@ -76,7 +76,7 @@ update_eval_breaker_from_thread(PyInterpreterState *interp, PyThreadState *tstat
             _Py_set_eval_breaker_bit(interp, _PY_CALLS_TO_DO_BIT, 1);
         }
         if (_Py_ThreadCanHandleSignals(interp)) {
-            if (_Py_atomic_load(&_PyRuntime.signals.is_tripped)) {
+            if (_Py_atomic_load_int(&_PyRuntime.signals.is_tripped)) {
                 _Py_set_eval_breaker_bit(interp, _PY_SIGNALS_PENDING_BIT, 1);
             }
         }