GH-103082: Implementation of PEP 669: Low Impact Monitoring for CPython (GH-103083)

* The majority of the monitoring code is in instrumentation.c

* The new instrumentation bytecodes are in bytecodes.c

* legacy_tracing.c adapts the new API to the old sys.setrace and sys.setprofile APIs

1 files changed, 98 insertions, 537 deletions

diff --git a/Python/ceval.c b/Python/ceval.c
index 7d60cf9..a38c9ec 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -10,6 +10,7 @@
 #include "pycore_function.h"
 #include "pycore_intrinsics.h"
 #include "pycore_long.h"          // _PyLong_GetZero()
+#include "pycore_instruments.h"
 #include "pycore_object.h"        // _PyObject_GC_TRACK()
 #include "pycore_moduleobject.h"  // PyModuleObject
 #include "pycore_opcode.h"        // EXTRA_CASES
@@ -92,13 +93,6 @@
 #define _Py_atomic_load_relaxed_int32(ATOMIC_VAL) _Py_atomic_load_relaxed(ATOMIC_VAL)
 #endif
 
-/* Forward declarations */
-static PyObject *trace_call_function(
-    PyThreadState *tstate, PyObject *callable, PyObject **stack,
-    Py_ssize_t oparg, PyObject *kwnames);
-static PyObject * do_call_core(
-    PyThreadState *tstate, PyObject *func,
-    PyObject *callargs, PyObject *kwdict, int use_tracing);
 
 #ifdef LLTRACE
 static void
@@ -179,19 +173,22 @@ lltrace_resume_frame(_PyInterpreterFrame *frame)
     PyErr_SetRaisedException(exc);
 }
 #endif
-static int call_trace(Py_tracefunc, PyObject *,
-                      PyThreadState *, _PyInterpreterFrame *,
-                      int, PyObject *);
-static int call_trace_protected(Py_tracefunc, PyObject *,
-                                PyThreadState *, _PyInterpreterFrame *,
-                                int, PyObject *);
-static void call_exc_trace(Py_tracefunc, PyObject *,
-                           PyThreadState *, _PyInterpreterFrame *);
-static int maybe_call_line_trace(Py_tracefunc, PyObject *,
-                                 PyThreadState *, _PyInterpreterFrame *, int);
-static void maybe_dtrace_line(_PyInterpreterFrame *, PyTraceInfo *, int);
-static void dtrace_function_entry(_PyInterpreterFrame *);
-static void dtrace_function_return(_PyInterpreterFrame *);
+
+static void monitor_raise(PyThreadState *tstate,
+                 _PyInterpreterFrame *frame,
+                 _Py_CODEUNIT *instr);
+static int monitor_stop_iteration(PyThreadState *tstate,
+                 _PyInterpreterFrame *frame,
+                 _Py_CODEUNIT *instr);
+static void monitor_unwind(PyThreadState *tstate,
+                 _PyInterpreterFrame *frame,
+                 _Py_CODEUNIT *instr);
+static void monitor_handled(PyThreadState *tstate,
+                 _PyInterpreterFrame *frame,
+                 _Py_CODEUNIT *instr, PyObject *exc);
+static void monitor_throw(PyThreadState *tstate,
+                 _PyInterpreterFrame *frame,
+                 _Py_CODEUNIT *instr);
 
 static PyObject * import_name(PyThreadState *, _PyInterpreterFrame *,
                               PyObject *, PyObject *, PyObject *);
@@ -217,21 +214,6 @@ _PyEvalFrameClearAndPop(PyThreadState *tstate, _PyInterpreterFrame *frame);
     "cannot access free variable '%s' where it is not associated with a" \
     " value in enclosing scope"
 
-#ifndef NDEBUG
-/* Ensure that tstate is valid: sanity check for PyEval_AcquireThread() and
-   PyEval_RestoreThread(). Detect if tstate memory was freed. It can happen
-   when a thread continues to run after Python finalization, especially
-   daemon threads. */
-static int
-is_tstate_valid(PyThreadState *tstate)
-{
-    assert(!_PyMem_IsPtrFreed(tstate));
-    assert(!_PyMem_IsPtrFreed(tstate->interp));
-    return 1;
-}
-#endif
-
-
 #ifdef HAVE_ERRNO_H
 #include <errno.h>
 #endif
@@ -596,63 +578,6 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
 
 #include "ceval_macros.h"
 
-static int
-trace_function_entry(PyThreadState *tstate, _PyInterpreterFrame *frame)
-{
-    if (tstate->c_tracefunc != NULL) {
-        /* tstate->c_tracefunc, if defined, is a
-            function that will be called on *every* entry
-            to a code block.  Its return value, if not
-            None, is a function that will be called at
-            the start of each executed line of code.
-            (Actually, the function must return itself
-            in order to continue tracing.)  The trace
-            functions are called with three arguments:
-            a pointer to the current frame, a string
-            indicating why the function is called, and
-            an argument which depends on the situation.
-            The global trace function is also called
-            whenever an exception is detected. */
-        if (call_trace_protected(tstate->c_tracefunc,
-                                    tstate->c_traceobj,
-                                    tstate, frame,
-                                    PyTrace_CALL, Py_None)) {
-            /* Trace function raised an error */
-            return -1;
-        }
-    }
-    if (tstate->c_profilefunc != NULL) {
-        /* Similar for c_profilefunc, except it needn't
-            return itself and isn't called for "line" events */
-        if (call_trace_protected(tstate->c_profilefunc,
-                                    tstate->c_profileobj,
-                                    tstate, frame,
-                                    PyTrace_CALL, Py_None)) {
-            /* Profile function raised an error */
-            return -1;
-        }
-    }
-    return 0;
-}
-
-static int
-trace_function_exit(PyThreadState *tstate, _PyInterpreterFrame *frame, PyObject *retval)
-{
-    if (tstate->c_tracefunc) {
-        if (call_trace_protected(tstate->c_tracefunc, tstate->c_traceobj,
-                                    tstate, frame, PyTrace_RETURN, retval)) {
-            return -1;
-        }
-    }
-    if (tstate->c_profilefunc) {
-        if (call_trace_protected(tstate->c_profilefunc, tstate->c_profileobj,
-                                    tstate, frame, PyTrace_RETURN, retval)) {
-            return -1;
-        }
-    }
-    return 0;
-}
-
 
 int _Py_CheckRecursiveCallPy(
     PyThreadState *tstate)
@@ -730,7 +655,6 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
      * strict stack discipline must be maintained.
      */
     _PyCFrame *prev_cframe = tstate->cframe;
-    cframe.use_tracing = prev_cframe->use_tracing;
     cframe.previous = prev_cframe;
     tstate->cframe = &cframe;
 
@@ -765,8 +689,11 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
         if (_Py_EnterRecursivePy(tstate)) {
             goto exit_unwind;
         }
-        TRACE_FUNCTION_THROW_ENTRY();
-        DTRACE_FUNCTION_ENTRY();
+        /* Because this avoids the RESUME,
+         * we need to update instrumentation */
+        _Py_Instrument(frame->f_code, tstate->interp);
+        monitor_throw(tstate, frame, frame->prev_instr);
+        /* TO DO -- Monitor throw entry. */
         goto resume_with_error;
     }
 
@@ -781,15 +708,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
     assert(_PyInterpreterFrame_LASTI(frame) >= -1); \
     /* Jump back to the last instruction executed... */ \
     next_instr = frame->prev_instr + 1; \
-    stack_pointer = _PyFrame_GetStackPointer(frame); \
-    /* Set stackdepth to -1. \
-        Update when returning or calling trace function. \
-        Having stackdepth <= 0 ensures that invalid \
-        values are not visible to the cycle GC. \
-        We choose -1 rather than 0 to assist debugging. \
-        */ \
-    frame->stacktop = -1;
-
+    stack_pointer = _PyFrame_GetStackPointer(frame);
 
 start_frame:
     if (_Py_EnterRecursivePy(tstate)) {
@@ -846,91 +765,6 @@ handle_eval_breaker:
 #include "generated_cases.c.h"
 
 #if USE_COMPUTED_GOTOS
-        TARGET_DO_TRACING:
-#else
-        case DO_TRACING:
-#endif
-    {
-        assert(cframe.use_tracing);
-        assert(tstate->tracing == 0);
-        if (INSTR_OFFSET() >= frame->f_code->_co_firsttraceable) {
-            int instr_prev = _PyInterpreterFrame_LASTI(frame);
-            frame->prev_instr = next_instr;
-            NEXTOPARG();
-            // No _PyOpcode_Deopt here, since RESUME has no optimized forms:
-            if (opcode == RESUME) {
-                if (oparg < 2) {
-                    CHECK_EVAL_BREAKER();
-                }
-                /* Call tracing */
-                TRACE_FUNCTION_ENTRY();
-                DTRACE_FUNCTION_ENTRY();
-            }
-            else {
-                /* line-by-line tracing support */
-                if (PyDTrace_LINE_ENABLED()) {
-                    maybe_dtrace_line(frame, &tstate->trace_info, instr_prev);
-                }
-
-                if (cframe.use_tracing &&
-                    tstate->c_tracefunc != NULL && !tstate->tracing) {
-                    int err;
-                    /* see maybe_call_line_trace()
-                    for expository comments */
-                    _PyFrame_SetStackPointer(frame, stack_pointer);
-
-                    err = maybe_call_line_trace(tstate->c_tracefunc,
-                                                tstate->c_traceobj,
-                                                tstate, frame, instr_prev);
-                    // Reload possibly changed frame fields:
-                    stack_pointer = _PyFrame_GetStackPointer(frame);
-                    frame->stacktop = -1;
-                    // next_instr is only reloaded if tracing *does not* raise.
-                    // This is consistent with the behavior of older Python
-                    // versions. If a trace function sets a new f_lineno and
-                    // *then* raises, we use the *old* location when searching
-                    // for an exception handler, displaying the traceback, and
-                    // so on:
-                    if (err) {
-                        // next_instr wasn't incremented at the start of this
-                        // instruction. Increment it before handling the error,
-                        // so that it looks the same as a "normal" instruction:
-                        next_instr++;
-                        goto error;
-                    }
-                    // Reload next_instr. Don't increment it, though, since
-                    // we're going to re-dispatch to the "true" instruction now:
-                    next_instr = frame->prev_instr;
-                }
-            }
-        }
-        NEXTOPARG();
-        PRE_DISPATCH_GOTO();
-        // No _PyOpcode_Deopt here, since EXTENDED_ARG has no optimized forms:
-        while (opcode == EXTENDED_ARG) {
-            // CPython hasn't ever traced the instruction after an EXTENDED_ARG.
-            // Inline the EXTENDED_ARG here, so we can avoid branching there:
-            INSTRUCTION_START(EXTENDED_ARG);
-            opcode = next_instr->op.code;
-            oparg = oparg << 8 | next_instr->op.arg;
-            // Make sure the next instruction isn't a RESUME, since that needs
-            // to trace properly (and shouldn't have an EXTENDED_ARG, anyways):
-            assert(opcode != RESUME);
-            PRE_DISPATCH_GOTO();
-        }
-        opcode = _PyOpcode_Deopt[opcode];
-        if (_PyOpcode_Caches[opcode]) {
-            uint16_t *counter = &next_instr[1].cache;
-            // The instruction is going to decrement the counter, so we need to
-            // increment it here to make sure it doesn't try to specialize:
-            if (!ADAPTIVE_COUNTER_IS_MAX(*counter)) {
-                INCREMENT_ADAPTIVE_COUNTER(*counter);
-            }
-        }
-        DISPATCH_GOTO();
-    }
-
-#if USE_COMPUTED_GOTOS
         _unknown_opcode:
 #else
         EXTRA_CASES  // From opcode.h, a 'case' for each unused opcode
@@ -988,12 +822,7 @@ error:
                 PyTraceBack_Here(f);
             }
         }
-
-        if (tstate->c_tracefunc != NULL) {
-            /* Make sure state is set to FRAME_UNWINDING for tracing */
-            call_exc_trace(tstate->c_tracefunc, tstate->c_traceobj,
-                           tstate, frame);
-        }
+        monitor_raise(tstate, frame, next_instr-1);
 
 exception_unwind:
         {
@@ -1012,8 +841,7 @@ exception_unwind:
                 }
                 assert(STACK_LEVEL() == 0);
                 _PyFrame_SetStackPointer(frame, stack_pointer);
-                TRACE_FUNCTION_UNWIND();
-                DTRACE_FUNCTION_EXIT();
+                monitor_unwind(tstate, frame, next_instr-1);
                 goto exit_unwind;
             }
 
@@ -1036,8 +864,10 @@ exception_unwind:
                 available to the handler,
                 so a program can emulate the
                 Python main loop. */
-            PUSH(_PyErr_GetRaisedException(tstate));
+            PyObject *exc = _PyErr_GetRaisedException(tstate);
+            PUSH(exc);
             JUMPTO(handler);
+            monitor_handled(tstate, frame, next_instr, exc);
             /* Resume normal execution */
             DISPATCH();
         }
@@ -1054,7 +884,6 @@ exit_unwind:
     if (frame == &entry_frame) {
         /* Restore previous cframe and exit */
         tstate->cframe = cframe.previous;
-        tstate->cframe->use_tracing = cframe.use_tracing;
         assert(tstate->cframe->current_frame == frame->previous);
         _Py_LeaveRecursiveCallTstate(tstate);
         return NULL;
@@ -2020,105 +1849,108 @@ Error:
     return 0;
 }
 
-static void
-call_exc_trace(Py_tracefunc func, PyObject *self,
-               PyThreadState *tstate,
-               _PyInterpreterFrame *f)
+static int
+do_monitor_exc(PyThreadState *tstate, _PyInterpreterFrame *frame,
+               _Py_CODEUNIT *instr, int event)
 {
-    PyObject *exc = _PyErr_GetRaisedException(tstate);
-    assert(exc && PyExceptionInstance_Check(exc));
-    PyObject *type = PyExceptionInstance_Class(exc);
-    PyObject *traceback = PyException_GetTraceback(exc);
-    if (traceback == NULL) {
-        traceback = Py_NewRef(Py_None);
+    assert(event < PY_MONITORING_UNGROUPED_EVENTS);
+    PyObject *exc = PyErr_GetRaisedException();
+    assert(exc != NULL);
+    int err = _Py_call_instrumentation_arg(tstate, event, frame, instr, exc);
+    if (err == 0) {
+        PyErr_SetRaisedException(exc);
     }
-    PyObject *arg = PyTuple_Pack(3, type, exc, traceback);
-    Py_XDECREF(traceback);
-
-    if (arg == NULL) {
-        _PyErr_SetRaisedException(tstate, exc);
-        return;
+    else {
+        Py_DECREF(exc);
     }
-    int err = call_trace(func, self, tstate, f, PyTrace_EXCEPTION, arg);
-    Py_DECREF(arg);
-    if (err == 0) {
-        _PyErr_SetRaisedException(tstate, exc);
+    return err;
+}
+
+static inline int
+no_tools_for_event(PyThreadState *tstate, _PyInterpreterFrame *frame, int event)
+{
+    _PyCoMonitoringData *data = frame->f_code->_co_monitoring;
+    if (data) {
+        if (data->active_monitors.tools[event] == 0) {
+            return 1;
+        }
     }
     else {
-        Py_XDECREF(exc);
+        if (tstate->interp->monitors.tools[event] == 0) {
+            return 1;
+        }
+    }
+    return 0;
+}
+
+static void
+monitor_raise(PyThreadState *tstate, _PyInterpreterFrame *frame,
+              _Py_CODEUNIT *instr)
+{
+    if (no_tools_for_event(tstate, frame, PY_MONITORING_EVENT_RAISE)) {
+        return;
     }
+    do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_RAISE);
 }
 
 static int
-call_trace_protected(Py_tracefunc func, PyObject *obj,
-                     PyThreadState *tstate, _PyInterpreterFrame *frame,
-                     int what, PyObject *arg)
+monitor_stop_iteration(PyThreadState *tstate, _PyInterpreterFrame *frame,
+                       _Py_CODEUNIT *instr)
 {
-    PyObject *exc = _PyErr_GetRaisedException(tstate);
-    int err = call_trace(func, obj, tstate, frame, what, arg);
-    if (err == 0)
-    {
-        _PyErr_SetRaisedException(tstate, exc);
+    if (no_tools_for_event(tstate, frame, PY_MONITORING_EVENT_STOP_ITERATION)) {
         return 0;
     }
-    else {
-        Py_XDECREF(exc);
-        return -1;
+    return do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_STOP_ITERATION);
+}
+
+static void
+monitor_unwind(PyThreadState *tstate,
+               _PyInterpreterFrame *frame,
+               _Py_CODEUNIT *instr)
+{
+    if (no_tools_for_event(tstate, frame, PY_MONITORING_EVENT_PY_UNWIND)) {
+        return;
     }
+    _Py_call_instrumentation_exc0(tstate, PY_MONITORING_EVENT_PY_UNWIND, frame, instr);
 }
 
+
 static void
-initialize_trace_info(PyTraceInfo *trace_info, _PyInterpreterFrame *frame)
+monitor_handled(PyThreadState *tstate,
+                _PyInterpreterFrame *frame,
+                _Py_CODEUNIT *instr, PyObject *exc)
 {
-    PyCodeObject *code = frame->f_code;
-    if (trace_info->code != code) {
-        trace_info->code = code;
-        _PyCode_InitAddressRange(code, &trace_info->bounds);
+    if (no_tools_for_event(tstate, frame, PY_MONITORING_EVENT_EXCEPTION_HANDLED)) {
+        return;
     }
+    _Py_call_instrumentation_arg(tstate, PY_MONITORING_EVENT_EXCEPTION_HANDLED, frame, instr, exc);
+}
+
+static void
+monitor_throw(PyThreadState *tstate,
+              _PyInterpreterFrame *frame,
+              _Py_CODEUNIT *instr)
+{
+    if (no_tools_for_event(tstate, frame, PY_MONITORING_EVENT_PY_THROW)) {
+        return;
+    }
+    _Py_call_instrumentation_exc0(tstate, PY_MONITORING_EVENT_PY_THROW, frame, instr);
 }
 
 void
 PyThreadState_EnterTracing(PyThreadState *tstate)
 {
+    assert(tstate->tracing >= 0);
     tstate->tracing++;
-    tstate->cframe->use_tracing = 0;
 }
 
 void
 PyThreadState_LeaveTracing(PyThreadState *tstate)
 {
-    assert(tstate->tracing > 0 && tstate->cframe->use_tracing == 0);
+    assert(tstate->tracing > 0);
     tstate->tracing--;
-    _PyThreadState_UpdateTracingState(tstate);
 }
 
-static int
-call_trace(Py_tracefunc func, PyObject *obj,
-           PyThreadState *tstate, _PyInterpreterFrame *frame,
-           int what, PyObject *arg)
-{
-    int result;
-    if (tstate->tracing) {
-        return 0;
-    }
-    PyFrameObject *f = _PyFrame_GetFrameObject(frame);
-    if (f == NULL) {
-        return -1;
-    }
-    int old_what = tstate->tracing_what;
-    tstate->tracing_what = what;
-    PyThreadState_EnterTracing(tstate);
-    assert(_PyInterpreterFrame_LASTI(frame) >= 0);
-    if (_PyCode_InitLineArray(frame->f_code)) {
-        return -1;
-    }
-    f->f_lineno = _PyCode_LineNumberFromArray(frame->f_code, _PyInterpreterFrame_LASTI(frame));
-    result = func(obj, f, what, arg);
-    f->f_lineno = 0;
-    PyThreadState_LeaveTracing(tstate);
-    tstate->tracing_what = old_what;
-    return result;
-}
 
 PyObject*
 _PyEval_CallTracing(PyObject *func, PyObject *args)
@@ -2126,7 +1958,6 @@ _PyEval_CallTracing(PyObject *func, PyObject *args)
     // Save and disable tracing
     PyThreadState *tstate = _PyThreadState_GET();
     int save_tracing = tstate->tracing;
-    int save_use_tracing = tstate->cframe->use_tracing;
     tstate->tracing = 0;
 
     // Call the tracing function
@@ -2134,81 +1965,9 @@ _PyEval_CallTracing(PyObject *func, PyObject *args)
 
     // Restore tracing
     tstate->tracing = save_tracing;
-    tstate->cframe->use_tracing = save_use_tracing;
     return result;
 }
 
-/* See Objects/lnotab_notes.txt for a description of how tracing works. */
-static int
-maybe_call_line_trace(Py_tracefunc func, PyObject *obj,
-                      PyThreadState *tstate, _PyInterpreterFrame *frame, int instr_prev)
-{
-    int result = 0;
-
-    /* If the last instruction falls at the start of a line or if it
-       represents a jump backwards, update the frame's line number and
-       then call the trace function if we're tracing source lines.
-    */
-    if (_PyCode_InitLineArray(frame->f_code)) {
-        return -1;
-    }
-    int lastline;
-    if (instr_prev <= frame->f_code->_co_firsttraceable) {
-        lastline = -1;
-    }
-    else {
-        lastline = _PyCode_LineNumberFromArray(frame->f_code, instr_prev);
-    }
-    int line = _PyCode_LineNumberFromArray(frame->f_code, _PyInterpreterFrame_LASTI(frame));
-    PyFrameObject *f = _PyFrame_GetFrameObject(frame);
-    if (f == NULL) {
-        return -1;
-    }
-    if (line != -1 && f->f_trace_lines) {
-        /* Trace backward edges (except in 'yield from') or if line number has changed */
-        int trace = line != lastline ||
-            (_PyInterpreterFrame_LASTI(frame) < instr_prev &&
-             // SEND has no quickened forms, so no need to use _PyOpcode_Deopt
-             // here:
-             frame->prev_instr->op.code != SEND);
-        if (trace) {
-            result = call_trace(func, obj, tstate, frame, PyTrace_LINE, Py_None);
-        }
-    }
-    /* Always emit an opcode event if we're tracing all opcodes. */
-    if (f->f_trace_opcodes && result == 0) {
-        result = call_trace(func, obj, tstate, frame, PyTrace_OPCODE, Py_None);
-    }
-    return result;
-}
-
-int
-_PyEval_SetProfile(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
-{
-    assert(is_tstate_valid(tstate));
-    /* The caller must hold the GIL */
-    assert(PyGILState_Check());
-
-    /* Call _PySys_Audit() in the context of the current thread state,
-       even if tstate is not the current thread state. */
-    PyThreadState *current_tstate = _PyThreadState_GET();
-    if (_PySys_Audit(current_tstate, "sys.setprofile", NULL) < 0) {
-        return -1;
-    }
-
-    tstate->c_profilefunc = func;
-    PyObject *old_profileobj = tstate->c_profileobj;
-    tstate->c_profileobj = Py_XNewRef(arg);
-    /* Flag that tracing or profiling is turned on */
-    _PyThreadState_UpdateTracingState(tstate);
-
-    // gh-98257: Only call Py_XDECREF() once the new profile function is fully
-    // set, so it's safe to call sys.setprofile() again (reentrant call).
-    Py_XDECREF(old_profileobj);
-
-    return 0;
-}
-
 void
 PyEval_SetProfile(Py_tracefunc func, PyObject *arg)
 {
@@ -2240,33 +1999,6 @@ PyEval_SetProfileAllThreads(Py_tracefunc func, PyObject *arg)
     }
 }
 
-int
-_PyEval_SetTrace(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
-{
-    assert(is_tstate_valid(tstate));
-    /* The caller must hold the GIL */
-    assert(PyGILState_Check());
-
-    /* Call _PySys_Audit() in the context of the current thread state,
-       even if tstate is not the current thread state. */
-    PyThreadState *current_tstate = _PyThreadState_GET();
-    if (_PySys_Audit(current_tstate, "sys.settrace", NULL) < 0) {
-        return -1;
-    }
-
-    tstate->c_tracefunc = func;
-    PyObject *old_traceobj = tstate->c_traceobj;
-    tstate->c_traceobj = Py_XNewRef(arg);
-    /* Flag that tracing or profiling is turned on */
-    _PyThreadState_UpdateTracingState(tstate);
-
-    // gh-98257: Only call Py_XDECREF() once the new trace function is fully
-    // set, so it's safe to call sys.settrace() again (reentrant call).
-    Py_XDECREF(old_traceobj);
-
-    return 0;
-}
-
 void
 PyEval_SetTrace(Py_tracefunc func, PyObject *arg)
 {
@@ -2492,114 +2224,6 @@ PyEval_GetFuncDesc(PyObject *func)
         return " object";
 }
 
-#define C_TRACE(x, call) \
-if (use_tracing && tstate->c_profilefunc) { \
-    if (call_trace(tstate->c_profilefunc, tstate->c_profileobj, \
-        tstate, tstate->cframe->current_frame, \
-        PyTrace_C_CALL, func)) { \
-        x = NULL; \
-    } \
-    else { \
-        x = call; \
-        if (tstate->c_profilefunc != NULL) { \
-            if (x == NULL) { \
-                call_trace_protected(tstate->c_profilefunc, \
-                    tstate->c_profileobj, \
-                    tstate, tstate->cframe->current_frame, \
-                    PyTrace_C_EXCEPTION, func); \
-                /* XXX should pass (type, value, tb) */ \
-            } else { \
-                if (call_trace(tstate->c_profilefunc, \
-                    tstate->c_profileobj, \
-                    tstate, tstate->cframe->current_frame, \
-                    PyTrace_C_RETURN, func)) { \
-                    Py_DECREF(x); \
-                    x = NULL; \
-                } \
-            } \
-        } \
-    } \
-} else { \
-    x = call; \
-    }
-
-
-static PyObject *
-trace_call_function(PyThreadState *tstate,
-                    PyObject *func,
-                    PyObject **args, Py_ssize_t nargs,
-                    PyObject *kwnames)
-{
-    int use_tracing = 1;
-    PyObject *x;
-    if (PyCFunction_CheckExact(func) || PyCMethod_CheckExact(func)) {
-        C_TRACE(x, PyObject_Vectorcall(func, args, nargs, kwnames));
-        return x;
-    }
-    else if (Py_IS_TYPE(func, &PyMethodDescr_Type) && nargs > 0) {
-        /* We need to create a temporary bound method as argument
-           for profiling.
-
-           If nargs == 0, then this cannot work because we have no
-           "self". In any case, the call itself would raise
-           TypeError (foo needs an argument), so we just skip
-           profiling. */
-        PyObject *self = args[0];
-        func = Py_TYPE(func)->tp_descr_get(func, self, (PyObject*)Py_TYPE(self));
-        if (func == NULL) {
-            return NULL;
-        }
-        C_TRACE(x, PyObject_Vectorcall(func,
-                                        args+1, nargs-1,
-                                        kwnames));
-        Py_DECREF(func);
-        return x;
-    }
-    return PyObject_Vectorcall(func, args, nargs | PY_VECTORCALL_ARGUMENTS_OFFSET, kwnames);
-}
-
-static PyObject *
-do_call_core(PyThreadState *tstate,
-             PyObject *func,
-             PyObject *callargs,
-             PyObject *kwdict,
-             int use_tracing
-            )
-{
-    PyObject *result;
-    if (PyCFunction_CheckExact(func) || PyCMethod_CheckExact(func)) {
-        C_TRACE(result, PyObject_Call(func, callargs, kwdict));
-        return result;
-    }
-    else if (Py_IS_TYPE(func, &PyMethodDescr_Type)) {
-        Py_ssize_t nargs = PyTuple_GET_SIZE(callargs);
-        if (nargs > 0 && use_tracing) {
-            /* We need to create a temporary bound method as argument
-               for profiling.
-
-               If nargs == 0, then this cannot work because we have no
-               "self". In any case, the call itself would raise
-               TypeError (foo needs an argument), so we just skip
-               profiling. */
-            PyObject *self = PyTuple_GET_ITEM(callargs, 0);
-            func = Py_TYPE(func)->tp_descr_get(func, self, (PyObject*)Py_TYPE(self));
-            if (func == NULL) {
-                return NULL;
-            }
-
-            C_TRACE(result, _PyObject_FastCallDictTstate(
-                                    tstate, func,
-                                    &_PyTuple_ITEMS(callargs)[1],
-                                    nargs - 1,
-                                    kwdict));
-            Py_DECREF(func);
-            return result;
-        }
-    }
-    EVAL_CALL_STAT_INC_IF_FUNCTION(EVAL_CALL_FUNCTION_EX, func);
-    return PyObject_Call(func, callargs, kwdict);
-}
-
 /* Extract a slice index from a PyLong or an object with the
    nb_index slot defined, and store in *pi.
    Silently reduce values larger than PY_SSIZE_T_MAX to PY_SSIZE_T_MAX,
@@ -2973,69 +2597,6 @@ PyUnstable_Eval_RequestCodeExtraIndex(freefunc free)
     return new_index;
 }
 
-static void
-dtrace_function_entry(_PyInterpreterFrame *frame)
-{
-    const char *filename;
-    const char *funcname;
-    int lineno;
-
-    PyCodeObject *code = frame->f_code;
-    filename = PyUnicode_AsUTF8(code->co_filename);
-    funcname = PyUnicode_AsUTF8(code->co_name);
-    lineno = _PyInterpreterFrame_GetLine(frame);
-
-    PyDTrace_FUNCTION_ENTRY(filename, funcname, lineno);
-}
-
-static void
-dtrace_function_return(_PyInterpreterFrame *frame)
-{
-    const char *filename;
-    const char *funcname;
-    int lineno;
-
-    PyCodeObject *code = frame->f_code;
-    filename = PyUnicode_AsUTF8(code->co_filename);
-    funcname = PyUnicode_AsUTF8(code->co_name);
-    lineno = _PyInterpreterFrame_GetLine(frame);
-
-    PyDTrace_FUNCTION_RETURN(filename, funcname, lineno);
-}
-
-/* DTrace equivalent of maybe_call_line_trace. */
-static void
-maybe_dtrace_line(_PyInterpreterFrame *frame,
-                  PyTraceInfo *trace_info,
-                  int instr_prev)
-{
-    const char *co_filename, *co_name;
-
-    /* If the last instruction executed isn't in the current
-       instruction window, reset the window.
-    */
-    initialize_trace_info(trace_info, frame);
-    int lastline = _PyCode_CheckLineNumber(instr_prev*sizeof(_Py_CODEUNIT), &trace_info->bounds);
-    int addr = _PyInterpreterFrame_LASTI(frame) * sizeof(_Py_CODEUNIT);
-    int line = _PyCode_CheckLineNumber(addr, &trace_info->bounds);
-    if (line != -1) {
-        /* Trace backward edges or first instruction of a new line */
-        if (_PyInterpreterFrame_LASTI(frame) < instr_prev ||
-            (line != lastline && addr == trace_info->bounds.ar_start))
-        {
-            co_filename = PyUnicode_AsUTF8(frame->f_code->co_filename);
-            if (!co_filename) {
-                co_filename = "?";
-            }
-            co_name = PyUnicode_AsUTF8(frame->f_code->co_name);
-            if (!co_name) {
-                co_name = "?";
-            }
-            PyDTrace_LINE(co_filename, co_name, line);
-        }
-    }
-}
-
 /* Implement Py_EnterRecursiveCall() and Py_LeaveRecursiveCall() as functions
    for the limited API. */