use prev_traced_instr instead of prev_instr in line tracing

iritkatriel · Sep 29, 2023 · 6f0fe7b · 6f0fe7b
1 parent b3b55ee
commit 6f0fe7b
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Showing 3 changed files with 18 additions and 13 deletions.
diff --git a/Include/internal/pycore_frame.h b/Include/internal/pycore_frame.h
@@ -63,6 +63,7 @@ typedef struct _PyInterpreterFrame {
     // example, it may be an inline CACHE entry, an instruction we just jumped
     // over, or (in the case of a newly-created frame) a totally invalid value:
     _Py_CODEUNIT *prev_instr;
+    _Py_CODEUNIT *prev_traced_instr;
     /* The instruction that is currently executing (possibly not started yet). */
     _Py_CODEUNIT *instr_ptr;
     int stacktop;  /* Offset of TOS from localsplus  */
@@ -173,6 +174,7 @@ _PyFrame_Initialize(
     frame->f_locals = locals;
     frame->stacktop = code->co_nlocalsplus;
     frame->frame_obj = NULL;
+    frame->prev_traced_instr = NULL;
     frame->prev_instr = _PyCode_CODE(code) - 1;
     frame->instr_ptr = _PyCode_CODE(code);
     frame->return_offset = 0;
@@ -339,6 +341,7 @@ _PyFrame_PushTrampolineUnchecked(PyThreadState *tstate, PyCodeObject *code, int
     frame->f_locals = NULL;
     frame->stacktop = code->co_nlocalsplus + stackdepth;
     frame->frame_obj = NULL;
+    frame->prev_traced_instr = NULL;
     frame->prev_instr = _PyCode_CODE(code) + previous_instr;
     frame->instr_ptr = _PyCode_CODE(code) + previous_instr + 1;
     frame->owner = FRAME_OWNED_BY_THREAD;

diff --git a/Python/ceval.c b/Python/ceval.c
@@ -791,8 +791,9 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
         case INSTRUMENTED_LINE:
 #endif
     {
-        _Py_CODEUNIT *prev = frame->prev_instr;
-        _Py_CODEUNIT *here = frame->instr_ptr = frame->prev_instr = next_instr;
+        DUMP_FRAME("INSTRUMENTED_LINE");
+        _Py_CODEUNIT *prev = frame->prev_traced_instr;
+        _Py_CODEUNIT *here = frame->instr_ptr = frame->prev_instr = frame->prev_traced_instr = next_instr;
         _PyFrame_SetStackPointer(frame, stack_pointer);
         int original_opcode = _Py_call_instrumentation_line(
                 tstate, frame, here, prev);
@@ -801,7 +802,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
             next_instr = here+1;
             goto error;
         }
-        next_instr = frame->prev_instr;
+        next_instr = frame->prev_traced_instr;
         if (next_instr != here) {
             DISPATCH();
         }

diff --git a/Python/instrumentation.c b/Python/instrumentation.c
@@ -1120,7 +1120,6 @@ _Py_Instrumentation_GetLine(PyCodeObject *code, int index)
 int
 _Py_call_instrumentation_line(PyThreadState *tstate, _PyInterpreterFrame* frame, _Py_CODEUNIT *instr, _Py_CODEUNIT *prev)
 {
-    assert(frame->prev_instr == instr);
     PyCodeObject *code = _PyFrame_GetCode(frame);
     assert(is_version_up_to_date(code, tstate->interp));
     assert(instrumentation_cross_checks(tstate->interp, code));
@@ -1135,15 +1134,17 @@ _Py_call_instrumentation_line(PyThreadState *tstate, _PyInterpreterFrame* frame,
     int8_t line_delta = line_data->line_delta;
     int line = compute_line(code, i, line_delta);
     assert(line >= 0);
-    int prev_index = (int)(prev - _PyCode_CODE(code));
-    int prev_line = _Py_Instrumentation_GetLine(code, prev_index);
-    if (prev_line == line) {
-        int prev_opcode = _PyCode_CODE(code)[prev_index].op.code;
-        /* RESUME and INSTRUMENTED_RESUME are needed for the operation of
-         * instrumentation, so must never be hidden by an INSTRUMENTED_LINE.
-         */
-        if (prev_opcode != RESUME && prev_opcode != INSTRUMENTED_RESUME) {
-            goto done;
+    if (prev != NULL) {
+        int prev_index = (int)(prev - _PyCode_CODE(code));
+        int prev_line = _Py_Instrumentation_GetLine(code, prev_index);
+        if (prev_line == line) {
+            int prev_opcode = _PyCode_CODE(code)[prev_index].op.code;
+            /* RESUME and INSTRUMENTED_RESUME are needed for the operation of
+             * instrumentation, so must never be hidden by an INSTRUMENTED_LINE.
+             */
+            if (prev_opcode != RESUME && prev_opcode != INSTRUMENTED_RESUME) {
+                goto done;
+            }
         }
     }
     uint8_t tools = code->_co_monitoring->line_tools != NULL ?