Merged revisions 70546 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r70546 | antoine.pitrou | 2009-03-23 19:41:45 +0100 (lun., 23 mars 2009) | 9 lines

  Issue #4688: Add a heuristic so that tuples and dicts containing only
  untrackable objects are not tracked by the garbage collector. This can
  reduce the size of collections and therefore the garbage collection overhead
  on long-running programs, depending on their particular use of datatypes.

  (trivia: this makes the "binary_trees" benchmark from the Computer Language
  Shootout 40% faster)
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1 files changed, 11 insertions, 0 deletions

diff --git a/Include/objimpl.h b/Include/objimpl.h
index 20d9c241a8..5a27382537 100644
--- a/Include/objimpl.h
+++ b/Include/objimpl.h
@@ -282,6 +282,17 @@ extern PyGC_Head *_PyGC_generation0;
 	g->gc.gc_next = NULL; \
     } while (0);
 
+/* True if the object is currently tracked by the GC. */
+#define _PyObject_GC_IS_TRACKED(o) \
+	((_Py_AS_GC(o))->gc.gc_refs != _PyGC_REFS_UNTRACKED)
+ 
+/* True if the object may be tracked by the GC in the future, or already is.
+   This can be useful to implement some optimizations. */
+#define _PyObject_GC_MAY_BE_TRACKED(obj) \
+	(PyObject_IS_GC(obj) && \
+		(!PyTuple_CheckExact(obj) || _PyObject_GC_IS_TRACKED(obj)))
+
+
 PyAPI_FUNC(PyObject *) _PyObject_GC_Malloc(size_t);
 PyAPI_FUNC(PyObject *) _PyObject_GC_New(PyTypeObject *);
 PyAPI_FUNC(PyVarObject *) _PyObject_GC_NewVar(PyTypeObject *, Py_ssize_t);