Generational GC showing signs of working. One test case in

test suite fails.

* gc.c (FRESHQ_SIZE): New preprocessor symbol.
(backptr_oflow, freshq, freshq_head, freshq_tail): New static
variables.
(make_obj): Place newly allocated generation 0 object into
freshq. If freshq becomes full, transfer oldest item into
generation 1.
(mark_obj): If doing only a partial gc, then do not mark
objects which are not generation 0.
(mark_mem_region): Valgrind support: cannot mark t.type field undefined
because it is a bitfield. Just mark the first SIZEOF_PTR bytes
of the object defined.
(mark): Under partial gc, mark the table of back pointers.
(sweep_one): New static function from the prior guts of sweep.
Reachable objects now get promoted to generation 1.
(sweep): Under partial gc, sweep just the freshq which identifies
the generation 0 objects, rather than the entire linked list of all the
heaps.
(gc): Trigger full gc also if the backptr list has overflowed
due to gc having been disabled.
Under generational gc, reset the static variables afterward:
clear the list of backpointers, and the freshq.
(gc_is_reachable): Under partial gc, report any mature object
as reachable.
(gc_set, gc_mutated): Handle backptr array overflow situation
when gc is disabled.
(gc_push): Bugfix: it is the newly pushed cons cell that has to be
marked as a root, not the value being pushed.

* hash.c (sethash): Use set macro for storing value.

* lib.h (set, mut, mpush): Fix wrong-way #if test for these macros.
The trivial versions were being defined uner CONFIG_GEN_GC and vice
versa!

1 files changed, 5 insertions, 4 deletions

diff --git a/lib.h b/lib.h
index 61af0d45..6a3568db 100644
--- a/lib.h
+++ b/lib.h
@@ -229,13 +229,14 @@ union obj {
 };
 
 #if CONFIG_GEN_GC
-#define set(place, val) ((place) = (val))
-#define mut(obj)
-#define mpush(val, place) (push(val, &(place)))
-#else
+val gc_set(val *, val);
 #define set(place, val) (gc_set(&(place), val))
 #define mut(obj) (gc_mutated(obj));
 #define mpush(val, place) (gc_push(val, &(place)))
+#else
+#define set(place, val) ((place) = (val))
+#define mut(obj)
+#define mpush(val, place) (push(val, &(place)))
 #endif
 
 INLINE cnum tag(val obj) { return ((cnum) obj) & TAG_MASK; }