bpo-43760: Add PyThreadState_EnterTracing() (GH-28542)

Add PyThreadState_EnterTracing() and PyThreadState_LeaveTracing()
functions to the limited C API to suspend and resume tracing and
profiling.

Add an unit test on the PyThreadState C API to _testcapi.

Add also internal _PyThreadState_DisableTracing() and
_PyThreadState_ResetTracing().

1 files changed, 7 insertions, 10 deletions

diff --git a/Python/ceval.c b/Python/ceval.c
index de71ae5..8986872 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -6187,7 +6187,7 @@ call_trace(Py_tracefunc func, PyObject *obj,
     if (tstate->tracing)
         return 0;
     tstate->tracing++;
-    tstate->cframe->use_tracing = 0;
+    _PyThreadState_DisableTracing(tstate);
     PyFrameObject *f = _PyFrame_GetFrameObject(frame);
     if (f == NULL) {
         return -1;
@@ -6201,8 +6201,7 @@ call_trace(Py_tracefunc func, PyObject *obj,
     }
     result = func(obj, f, what, arg);
     f->f_lineno = 0;
-    tstate->cframe->use_tracing = ((tstate->c_tracefunc != NULL)
-                           || (tstate->c_profilefunc != NULL)) ? 255 : 0;
+    _PyThreadState_ResetTracing(tstate);
     tstate->tracing--;
     return result;
 }
@@ -6216,8 +6215,7 @@ _PyEval_CallTracing(PyObject *func, PyObject *args)
     PyObject *result;
 
     tstate->tracing = 0;
-    tstate->cframe->use_tracing = ((tstate->c_tracefunc != NULL)
-                           || (tstate->c_profilefunc != NULL)) ? 255 : 0;
+    _PyThreadState_ResetTracing(tstate);
     result = PyObject_Call(func, args, NULL);
     tstate->tracing = save_tracing;
     tstate->cframe->use_tracing = save_use_tracing;
@@ -6274,7 +6272,7 @@ _PyEval_SetProfile(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
     tstate->c_profilefunc = NULL;
     tstate->c_profileobj = NULL;
     /* Must make sure that tracing is not ignored if 'profileobj' is freed */
-    tstate->cframe->use_tracing = tstate->c_tracefunc != NULL;
+    _PyThreadState_ResetTracing(tstate);
     Py_XDECREF(profileobj);
 
     Py_XINCREF(arg);
@@ -6282,7 +6280,7 @@ _PyEval_SetProfile(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
     tstate->c_profilefunc = func;
 
     /* Flag that tracing or profiling is turned on */
-    tstate->cframe->use_tracing = (func != NULL) || (tstate->c_tracefunc != NULL) ? 255 : 0;
+    _PyThreadState_ResetTracing(tstate);
     return 0;
 }
 
@@ -6315,7 +6313,7 @@ _PyEval_SetTrace(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
     tstate->c_tracefunc = NULL;
     tstate->c_traceobj = NULL;
     /* Must make sure that profiling is not ignored if 'traceobj' is freed */
-    tstate->cframe->use_tracing = (tstate->c_profilefunc != NULL) ? 255 : 0;
+    _PyThreadState_ResetTracing(tstate);
     Py_XDECREF(traceobj);
 
     Py_XINCREF(arg);
@@ -6323,8 +6321,7 @@ _PyEval_SetTrace(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
     tstate->c_tracefunc = func;
 
     /* Flag that tracing or profiling is turned on */
-    tstate->cframe->use_tracing = ((func != NULL)
-                           || (tstate->c_profilefunc != NULL)) ? 255 : 0;
+    _PyThreadState_ResetTracing(tstate);
 
     return 0;
 }