Mercurial > cpython-lru_cache-weakref

diff Include/code.h @ 54297:dddf424bd669 legacy-trunk

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Issue #6042: lnotab-based tracing is very complicated and isn't documented very well. There were at least 3 comment blocks purporting to document co_lnotab, and none did a very good job. This patch unifies them into Objects/lnotab_notes.txt which tries to completely capture the current state of affairs. I also discovered that we've attached 2 layers of patches to the basic tracing scheme. The first layer avoids jumping to instructions that don't start a line, to avoid problems in if statements and while loops. The second layer discovered that jumps backward do need to trace at instructions that don't start a line, so it added extra lnotab entries for 'while' and 'for' loops, and added a special case for backward jumps within the same line. I replaced these patches by just treating forward and backward jumps differently.
author Jeffrey Yasskin <jyasskin@gmail.com>
date Sat, 23 May 2009 23:23:01 +0000
parents 9ef683d41c9b
children 22f589a8e3ab
line wrap: on
line diff
--- a/Include/code.h	Sat May 23 21:48:06 2009 +0000
+++ b/Include/code.h	Sat May 23 23:23:01 2009 +0000
@@ -23,7 +23,8 @@
     PyObject *co_filename;	/* string (where it was loaded from) */
     PyObject *co_name;		/* string (name, for reference) */
     int co_firstlineno;		/* first source line number */
-    PyObject *co_lnotab;	/* string (encoding addr<->lineno mapping) */
+    PyObject *co_lnotab;	/* string (encoding addr<->lineno mapping) See
+				   Objects/lnotab_notes.txt for details. */
     void *co_zombieframe;     /* for optimization only (see frameobject.c) */
 } PyCodeObject;
 
@@ -90,15 +91,11 @@
         int ap_upper;
 } PyAddrPair;
 
-/* Check whether lasti (an instruction offset) falls outside bounds
-   and whether it is a line number that should be traced.  Returns
-   a line number if it should be traced or -1 if the line should not.
-
-   If lasti is not within bounds, updates bounds.
+/* Update *bounds to describe the first and one-past-the-last instructions in the
+   same line as lasti.  Return the number of that line.
 */
-
-PyAPI_FUNC(int) PyCode_CheckLineNumber(PyCodeObject* co,
-                                       int lasti, PyAddrPair *bounds);
+PyAPI_FUNC(int) _PyCode_CheckLineNumber(PyCodeObject* co,
+                                        int lasti, PyAddrPair *bounds);
 
 PyAPI_FUNC(PyObject*) PyCode_Optimize(PyObject *code, PyObject* consts,
                                       PyObject *names, PyObject *lineno_obj);