gh-102192: Replace PyErr_Fetch/Restore etc by more efficient alternatives (#102816)

Python/bytecodes.c

@@ -778,9 +778,7 @@ dummy_func(
             }
             assert(exc && PyExceptionInstance_Check(exc));
             Py_INCREF(exc);
-            PyObject *typ = Py_NewRef(PyExceptionInstance_Class(exc));
+            _PyErr_SetRaisedException(tstate, exc);
-            PyObject *tb = PyException_GetTraceback(exc);
-            _PyErr_Restore(tstate, typ, exc, tb);
             goto exception_unwind;
         }
 
@@ -791,9 +789,7 @@ dummy_func(
             }
             else {
                 Py_INCREF(exc);
-                PyObject *typ = Py_NewRef(PyExceptionInstance_Class(exc));
+                _PyErr_SetRaisedException(tstate, exc);
-                PyObject *tb = PyException_GetTraceback(exc);
-                _PyErr_Restore(tstate, typ, exc, tb);
                 goto exception_unwind;
             }
         }

Python/import.c

@@ -389,8 +389,7 @@ PyImport_AddModule(const char *name)
 static void
 remove_module(PyThreadState *tstate, PyObject *name)
 {
-    PyObject *type, *value, *traceback;
+    PyObject *exc = _PyErr_GetRaisedException(tstate);
-    _PyErr_Fetch(tstate, &type, &value, &traceback);
 
     PyObject *modules = MODULES(tstate->interp);
     if (PyDict_CheckExact(modules)) {
@@ -403,7 +402,7 @@ remove_module(PyThreadState *tstate, PyObject *name)
         }
     }
 
-    _PyErr_ChainExceptions(type, value, traceback);
+    _PyErr_ChainExceptions1(exc);
 }
 
 
@@ -2324,32 +2323,34 @@ remove_importlib_frames(PyThreadState *tstate)
     const char *remove_frames = "_call_with_frames_removed";
     int always_trim = 0;
     int in_importlib = 0;
-    PyObject *exception, *value, *base_tb, *tb;
     PyObject **prev_link, **outer_link = NULL;
+    PyObject *base_tb = NULL;
 
     /* Synopsis: if it's an ImportError, we trim all importlib chunks
        from the traceback. We always trim chunks
        which end with a call to "_call_with_frames_removed". */
 
-    _PyErr_Fetch(tstate, &exception, &value, &base_tb);
+    PyObject *exc = _PyErr_GetRaisedException(tstate);
-    if (!exception || _PyInterpreterState_GetConfig(tstate->interp)->verbose) {
+    if (exc == NULL || _PyInterpreterState_GetConfig(tstate->interp)->verbose) {
         goto done;
     }
 
-    if (PyType_IsSubtype((PyTypeObject *) exception,
+    if (PyType_IsSubtype(Py_TYPE(exc), (PyTypeObject *) PyExc_ImportError)) {
-                         (PyTypeObject *) PyExc_ImportError))
         always_trim = 1;
+    }
 
+    assert(PyExceptionInstance_Check(exc));
+    base_tb = PyException_GetTraceback(exc);
     prev_link = &base_tb;
-    tb = base_tb;
+    PyObject *tb = base_tb;
     while (tb != NULL) {
+        assert(PyTraceBack_Check(tb));
         PyTracebackObject *traceback = (PyTracebackObject *)tb;
         PyObject *next = (PyObject *) traceback->tb_next;
         PyFrameObject *frame = traceback->tb_frame;
         PyCodeObject *code = PyFrame_GetCode(frame);
         int now_in_importlib;
 
-        assert(PyTraceBack_Check(tb));
         now_in_importlib = _PyUnicode_EqualToASCIIString(code->co_filename, importlib_filename) ||
                            _PyUnicode_EqualToASCIIString(code->co_filename, external_filename);
         if (now_in_importlib && !in_importlib) {
@@ -2370,15 +2371,14 @@ remove_importlib_frames(PyThreadState *tstate)
         Py_DECREF(code);
         tb = next;
     }
-    assert(PyExceptionInstance_Check(value));
-    assert((PyObject *)Py_TYPE(value) == exception);
     if (base_tb == NULL) {
         base_tb = Py_None;
         Py_INCREF(Py_None);
     }
-    PyException_SetTraceback(value, base_tb);
+    PyException_SetTraceback(exc, base_tb);
 done:
-    _PyErr_Restore(tstate, exception, value, base_tb);
+    Py_XDECREF(base_tb);
+    _PyErr_SetRaisedException(tstate, exc);
 }
 
 

Python/pythonrun.c

@@ -18,7 +18,7 @@
 #include "pycore_interp.h"        // PyInterpreterState.importlib
 #include "pycore_object.h"        // _PyDebug_PrintTotalRefs()
 #include "pycore_parser.h"        // _PyParser_ASTFromString()
-#include "pycore_pyerrors.h"      // _PyErr_Fetch, _Py_Offer_Suggestions
+#include "pycore_pyerrors.h"      // _PyErr_GetRaisedException, _Py_Offer_Suggestions
 #include "pycore_pylifecycle.h"   // _Py_UnhandledKeyboardInterrupt
 #include "pycore_pystate.h"       // _PyInterpreterState_GET()
 #include "pycore_sysmodule.h"     // _PySys_Audit()