Deal with situation when GC is disabled and the freshobj array runs out

of room.  This could happen when parsing a really large TXR program,
since gc is disabled during parsing. Currently it asserts, which
is not acceptable.

* gc.c (make_obj): If after gc, the freshobj array has not been
emptied (obviously because gc is disabled), do not assert.
Rather, set the full_gc flag to request a full garbage collection
when gc is re-enabled.  Furthermore, only place newly allocated objects
into freshobj if full_gc has not been set. Thus, if we exhaust the
freshobj array while gc is off, the full_gc flag is set, and we
discontinue use of that array. When gc is re-enabled, we will do a full
gc pass. A full gc pass ignores freshobj array, so it doesn't matter
that its use was discontinued.

2 files changed, 22 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index edfef9ac..2f1e3b68 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,22 @@
 2014-10-18  Kaz Kylheku  <kaz@kylheku.com>
 
+	Deal with situation when GC is disabled and the freshobj array runs out
+	of room.  This could happen when parsing a really large TXR program,
+	since gc is disabled during parsing. Currently it asserts, which
+	is not acceptable.
+
+	* gc.c (make_obj): If after gc, the freshobj array has not been
+	emptied (obviously because gc is disabled), do not assert.
+	Rather, set the full_gc flag to request a full garbage collection
+	when gc is re-enabled.  Furthermore, only place newly allocated objects
+	into freshobj if full_gc has not been set. Thus, if we exhaust the
+	freshobj array while gc is off, the full_gc flag is set, and we
+	discontinue use of that array. When gc is re-enabled, we will do a full
+	gc pass. A full gc pass ignores freshobj array, so it doesn't matter
+	that its use was discontinued.
+
+2014-10-18  Kaz Kylheku  <kaz@kylheku.com>
+
 	* match.c (mf_all): Drop data_lineno parameter. Initialize
 	the corresponding member based on whether or not data is nil.
 	(do_match_line, mf_from_ml, match_filter, match_fun, extract):
diff --git a/gc.c b/gc.c
index 850605c5..d3dd1f3c 100644
--- a/gc.c
+++ b/gc.c
@@ -165,7 +165,8 @@ val make_obj(void)
       malloc_delta >= opt_gc_delta)
   {
     gc();
-    assert (freshobj_idx < FRESHOBJ_VEC_SIZE);
+    if (freshobj_idx >= FRESHOBJ_VEC_SIZE)
+      full_gc = 1;
     prev_malloc_bytes = malloc_bytes;
   }
 #else
@@ -189,7 +190,8 @@ val make_obj(void)
 #endif
 #if CONFIG_GEN_GC
       ret->t.gen = 0;
-      freshobj[freshobj_idx++] = ret;
+      if (!full_gc)
+        freshobj[freshobj_idx++] = ret;
 #endif
       gc_bytes += sizeof (obj_t);
       return ret;
@@ -208,7 +210,7 @@ val make_obj(void)
     }
   }
 
-  return 0;
+  abort();
 }
 
 static void finalize(val obj)