Changeset 630Tweet

Timestamp:

May 10, 2011, 8:31:42 PM (11 years ago)

Author:

Sam Hocevar

Message:

lisp: fix a tail recursion bug in the List object collector that caused
excessive stack usage.

File:

• abuse/trunk/src/lisp/lisp_gc.cpp (modified) (3 diffs)

abuse/trunk/src/lisp/lisp_gc.cpp

@@ -55 +55 @@
 LList *LispGC::CollectList(LList *x)
 {
-    LList *last = NULL, *first = NULL;
+    LList *prev = NULL, *first = NULL;
 
     for (; x && item_type(x) == L_CONS_CELL; )
@@ -61 +61 @@
         LList *p = LList::Create();
         LObject *old_car = x->car;
-        LObject *old_cdr = x->cdr;
         LObject *old_x = x;
         x = (LList *)CDR(x);
@@ -68 +67 @@
 
         p->car = CollectObject(old_car);
-        p->cdr = CollectObject(old_cdr);
-
-        if (last)
-            last->cdr = p;
+
+        if (prev)
+            prev->cdr = p;
         else
             first = p;
-        last = p;
+        prev = p;
     }
     if (x)
-        last->cdr = CollectObject(x);
+        prev->cdr = CollectObject(x);
+
     return first; // we already set the collection pointers
 }