Index: Python/ceval.c
===================================================================
--- Python/ceval.c	(revision 72417)
+++ Python/ceval.c	(working copy)
@@ -2698,7 +2698,7 @@
 		default:
 			fprintf(stderr,
 				"XXX lineno: %d, opcode: %d\n",
-				PyCode_Addr2Line(f->f_code, f->f_lasti),
+				PyFrame_GetLineNumber(f),
 				opcode);
 			PyErr_SetString(PyExc_SystemError, "unknown opcode");
 			why = WHY_EXCEPTION;
Index: Python/traceback.c
===================================================================
--- Python/traceback.c	(revision 72417)
+++ Python/traceback.c	(working copy)
@@ -96,8 +96,7 @@
 		Py_XINCREF(frame);
 		tb->tb_frame = frame;
 		tb->tb_lasti = frame->f_lasti;
-		tb->tb_lineno = PyCode_Addr2Line(frame->f_code, 
-						 frame->f_lasti);
+		tb->tb_lineno = PyFrame_GetLineNumber(frame);
 		PyObject_GC_Track(tb);
 	}
 	return tb;
Index: Python/_warnings.c
===================================================================
--- Python/_warnings.c	(revision 72417)
+++ Python/_warnings.c	(working copy)
@@ -454,7 +454,7 @@
     }
     else {
         globals = f->f_globals;
-        *lineno = PyCode_Addr2Line(f->f_code, f->f_lasti);
+        *lineno = PyFrame_GetLineNumber(f);
     }
 
     *module = NULL;
Index: Include/code.h
===================================================================
--- Include/code.h	(revision 72417)
+++ Include/code.h	(working copy)
@@ -70,6 +70,10 @@
 	int, int, int, int, PyObject *, PyObject *, PyObject *, PyObject *,
 	PyObject *, PyObject *, PyObject *, PyObject *, int, PyObject *); 
         /* same as struct above */
+
+/* Return the line number associated with the specified bytecode index
+   in this code object.  If you just need the line number of a frame,
+   use PyFrame_GetLineNumber() instead. */
 PyAPI_FUNC(int) PyCode_Addr2Line(PyCodeObject *, int);
 
 /* for internal use only */
Index: Include/frameobject.h
===================================================================
--- Include/frameobject.h	(revision 72417)
+++ Include/frameobject.h	(working copy)
@@ -38,8 +38,11 @@
 
     PyThreadState *f_tstate;
     int f_lasti;		/* Last instruction if called */
-    /* As of 2.3 f_lineno is only valid when tracing is active (i.e. when
-       f_trace is set) -- at other times use PyCode_Addr2Line instead. */
+    /* Call PyFrame_GetLineNumber() instead of reading this field
+       directly.  As of 2.3 f_lineno is only valid when tracing is
+       active (i.e. when f_trace is set).  At other times we use
+       PyCode_Addr2Line to calculate the line from the current
+       bytecode index. */
     int f_lineno;		/* Current line number */
     int f_iblock;		/* index in f_blockstack */
     PyTryBlock f_blockstack[CO_MAXBLOCKS]; /* for try and loop blocks */
@@ -77,6 +80,9 @@
 
 PyAPI_FUNC(int) PyFrame_ClearFreeList(void);
 
+/* Return the line of code the frame is currently executing. */
+PyAPI_FUNC(int) PyFrame_GetLineNumber(PyFrameObject *);
+
 #ifdef __cplusplus
 }
 #endif
Index: Objects/frameobject.c
===================================================================
--- Objects/frameobject.c	(revision 72417)
+++ Objects/frameobject.c	(working copy)
@@ -60,17 +60,19 @@
 	return f->f_locals;
 }
 
-static PyObject *
-frame_getlineno(PyFrameObject *f, void *closure)
+int
+PyFrame_GetLineNumber(PyFrameObject *f)
 {
-	int lineno;
-
 	if (f->f_trace)
-		lineno = f->f_lineno;
+		return f->f_lineno;
 	else
-		lineno = PyCode_Addr2Line(f->f_code, f->f_lasti);
+		return PyCode_Addr2Line(f->f_code, f->f_lasti);
+}
 
-	return PyInt_FromLong(lineno);
+static PyObject *
+frame_getlineno(PyFrameObject *f, void *closure)
+{
+	return PyInt_FromLong(PyFrame_GetLineNumber(f));
 }
 
 /* Setter for f_lineno - you can set f_lineno from within a trace function in
@@ -351,16 +353,14 @@
 static int
 frame_settrace(PyFrameObject *f, PyObject* v, void *closure)
 {
+	PyObject* old_value;
+
 	/* We rely on f_lineno being accurate when f_trace is set. */
+	f->f_lineno = PyFrame_GetLineNumber(f);
 
-	PyObject* old_value = f->f_trace;
-
+	old_value = f->f_trace;
 	Py_XINCREF(v);
 	f->f_trace = v;
-
-	if (v != NULL)
-		f->f_lineno = PyCode_Addr2Line(f->f_code, f->f_lasti);
-
 	Py_XDECREF(old_value);
 
 	return 0;