Use struct for perf callbacks

Include/internal/pycore_ceval.h

@@ -67,28 +67,25 @@ extern PyObject* _PyEval_BuiltinsFromGlobals(
 
 // Trampoline API
 
-typedef void* (*trampoline_state_init)(void);
-typedef void (*trampoline_state_write)(void* state, const void *code_addr,
-                                       unsigned int code_size, PyCodeObject* code);
-typedef int (*trampoline_state_free)(void* state);
-extern int _PyPerfTrampoline_SetCallbacks(
-    trampoline_state_init init_state,
-    trampoline_state_write write_state,
-    trampoline_state_free free_state
-);
-extern void _PyPerfTrampoline_GetCallbacks(
-    trampoline_state_init *init_state,
-    trampoline_state_write *write_state,
-    trampoline_state_free *free_state
-);
+typedef struct {
+    // Callback to initialize the trampoline state
+    void* (*init_state)(void);
+    // Callback to register every trampoline being created
+    void (*write_state)(void* state, const void *code_addr,
+                        unsigned int code_size, PyCodeObject* code);
+    // Callback to free the trampoline state
+    int (*free_state)(void* state);
+} _PyPerf_Callbacks;
+
+extern int _PyPerfTrampoline_SetCallbacks(_PyPerf_Callbacks *);
+extern void _PyPerfTrampoline_GetCallbacks(_PyPerf_Callbacks *);
 extern int _PyPerfTrampoline_Init(int activate);
 extern int _PyPerfTrampoline_Fini(void);
 extern int _PyIsPerfTrampolineActive(void);
 extern PyStatus _PyPerfTrampoline_AfterFork_Child(void);
-
-extern void* _Py_perf_map_get_file(void);
-extern void _Py_perf_map_write_entry(void*, const void*, unsigned int, PyCodeObject*);
-extern int _Py_perf_map_close(void*);
+#ifdef _PY_HAVE_PERF_TRAMPOLINE
+extern _PyPerf_Callbacks _Py_perfmap_callbacks;
+#endif
 
 static inline PyObject*
 _PyEval_EvalFrame(PyThreadState *tstate, struct _PyInterpreterFrame *frame, int throwflag)

Objects/perf_trampoline.c

@@ -176,11 +176,10 @@ struct code_arena_st {
 typedef struct code_arena_st code_arena_t;
 
 struct trampoline_api_st {
-    trampoline_state_init
-        init_state;  // Callback to initialize the trampoline state
-    trampoline_state_write
-        write_state;  // Callback to register every trampoline being created
-    trampoline_state_free free_state;  // Callback to free the trampoline state
+    void* (*init_state)(void);
+    void (*write_state)(void* state, const void *code_addr,
+                        unsigned int code_size, PyCodeObject* code);
+    int (*free_state)(void* state);
     void *state;
 };
 
@@ -192,8 +191,9 @@ static code_arena_t *code_arena;
 static trampoline_api_t trampoline_api;
 
 static FILE *perf_map_file;
-void *
-_Py_perf_map_get_file(void)
+
+static void *
+perf_map_get_file(void)
 {
     if (perf_map_file) {
         return perf_map_file;
@@ -221,8 +221,8 @@ _Py_perf_map_get_file(void)
     return perf_map_file;
 }
 
-int
-_Py_perf_map_close(void *state)
+static int
+perf_map_close(void *state)
 {
     FILE *fp = (FILE *)state;
     int ret = 0;
@@ -234,8 +234,8 @@ _Py_perf_map_close(void *state)
     return ret;
 }
 
-void
-_Py_perf_map_write_entry(void *state, const void *code_addr,
+static void
+perf_map_write_entry(void *state, const void *code_addr,
                          unsigned int code_size, PyCodeObject *co)
 {
     assert(state != NULL);
@@ -257,6 +257,12 @@ _Py_perf_map_write_entry(void *state, const void *code_addr,
     fflush(method_file);
 }
 
+_PyPerf_Callbacks _Py_perfmap_callbacks = {
+    &perf_map_get_file,
+    &perf_map_write_entry,
+    &perf_map_close
+};
+
 static int
 new_code_arena(void)
 {
@@ -393,36 +399,32 @@ _PyIsPerfTrampolineActive(void)
 }
 
 void
-_PyPerfTrampoline_GetCallbacks(trampoline_state_init *init_state,
-                               trampoline_state_write *write_state,
-                               trampoline_state_free *free_state)
+_PyPerfTrampoline_GetCallbacks(_PyPerf_Callbacks *callbacks)
 {
-#ifdef _PY_HAVE_PERF_TRAMPOLINE
-    if (init_state) {
-        *init_state = trampoline_api.init_state;
-    }
-    if (write_state) {
-        *write_state = trampoline_api.write_state;
-    }
-    if (free_state) {
-        *free_state = trampoline_api.free_state;
+    if (callbacks == NULL) {
+        return;
     }
+#ifdef _PY_HAVE_PERF_TRAMPOLINE
+    callbacks->init_state = trampoline_api.init_state;
+    callbacks->write_state = trampoline_api.write_state;
+    callbacks->free_state = trampoline_api.free_state;
 #endif
     return;
 }
 
 int
-_PyPerfTrampoline_SetCallbacks(trampoline_state_init init_state,
-                               trampoline_state_write write_state,
-                               trampoline_state_free free_state)
+_PyPerfTrampoline_SetCallbacks(_PyPerf_Callbacks *callbacks)
 {
+    if (callbacks == NULL) {
+        return -1;
+    }
 #ifdef _PY_HAVE_PERF_TRAMPOLINE
     if (trampoline_api.state) {
         _PyPerfTrampoline_Fini();
     }
-    trampoline_api.init_state = init_state;
-    trampoline_api.write_state = write_state;
-    trampoline_api.free_state = free_state;
+    trampoline_api.init_state = callbacks->init_state;
+    trampoline_api.write_state = callbacks->write_state;
+    trampoline_api.free_state = callbacks->free_state;
     trampoline_api.state = NULL;
     perf_status = PERF_STATUS_OK;
 #endif

Python/pylifecycle.c

@@ -1153,9 +1153,8 @@ init_interp_main(PyThreadState *tstate)
 
 #ifdef _PY_HAVE_PERF_TRAMPOLINE
         if (config->perf_profiling) {
-            if (_PyPerfTrampoline_SetCallbacks(
-                    _Py_perf_map_get_file, _Py_perf_map_write_entry, _Py_perf_map_close
-                ) < 0 || _PyPerfTrampoline_Init(config->perf_profiling) < 0) {
+            if (_PyPerfTrampoline_SetCallbacks(&_Py_perfmap_callbacks) < 0 ||
+                    _PyPerfTrampoline_Init(config->perf_profiling) < 0) {
                 return _PyStatus_ERR("can't initialize the perf trampoline");
             }
         }

Python/sysmodule.c

@@ -2009,14 +2009,10 @@ sys_activate_stack_trampoline_impl(PyObject *module, const char *backend)
 {
     if (strcmp(backend, "perf") == 0) {
 #ifdef _PY_HAVE_PERF_TRAMPOLINE
-        trampoline_state_init init_callback = NULL; 
-        _PyPerfTrampoline_GetCallbacks(&init_callback, NULL, NULL);
-        if (init_callback != _Py_perf_map_get_file) {
-            if ( _PyPerfTrampoline_SetCallbacks(
-                    _Py_perf_map_get_file,
-                    _Py_perf_map_write_entry,
-                    _Py_perf_map_close
-                ) < 0 ) {
+        _PyPerf_Callbacks cur_cb;
+        _PyPerfTrampoline_GetCallbacks(&cur_cb);
+        if (cur_cb.init_state != _Py_perfmap_callbacks.init_state) {
+            if (_PyPerfTrampoline_SetCallbacks(&_Py_perfmap_callbacks) < 0 ) {
                 PyErr_SetString(PyExc_ValueError, "can't activate perf trampoline");
                 return NULL;
             }