* configure: Support a gen-gc configuration variable which

causes CONFIG_GEN_GC to be defined as 1 in config.h.

* eval.c (op_defvar, dwim_loc, op_modplace, transform_op): Handle
mutating assignments via set macro.
(op_dohash): Inform gc about mutated variables. TODO here.

* filter.c (trie_add, trie_compress): Handle mutating assignments
via set macro.

* gc.c (BACKPTR_VEC_SIZE, FULL_GC_INTERVAL): New preprocessor symbols.
(backptr, backptr_idx, partial_gc_count, full): New static variables.
(make_obj): Initialize generation to zero.
(gc): Added logic for deciding between full and partial gc.
(gc_set, gc_mutated): New functions.

* gc.h (gc_set, gc_mutated): Declared.

* hash.c (hash_mark): Changed useless use of vecref_l to vecref.
(gethash_f): Use set when assigning through *found since it
is a possible mutation.

* lib.c (car_l, cdr_l, vecref_l): Got rid of loc macro uses. Using the
value properly is going to be the caller's responsibility.
(push): push may be a mutation, so use set.
(intern): Uset set to mutate a hash entry.
(acons_new_l, aconsq_new_l): Use set when replacing *list.

* lib.h (PTR_BIT): New preprocessor symbol.
(obj_common): New macro for defining common object fields.
type_t is split into two bitfields, half a pointer wide,
allowing for generation to be represented.
(struct any, struct cons, struct string, struct sym, struct package,
struct func, struct vec, struct lazy_cons, struct cobj, struct env,
struct bignum, struct flonum): Use obj_common macro to defined
common fields.
(loc): Macro removed.
(set, mut): Macros conditionally defined for real functionality.
(list_collect, list_collect_nconc, list_collect_append): Replace
mutating operations with set.

* match.c (dest_set, v_cat, v_output, v_filter): Replace
mutating operations with set.

* stream.c (string_in_get_line, string_in_get_char,
strlist_out_put_string, strlist_out_put_char): Replace mutating
operations with set.

* unwind.c (uw_register_subtype): Replace mutating operation with set.

1 files changed, 50 insertions, 0 deletions

diff --git a/gc.c b/gc.c
index 7df908c6..a644be3a 100644
--- a/gc.c
+++ b/gc.c
@@ -44,6 +44,8 @@
 
 #define PROT_STACK_SIZE         1024
 #define HEAP_SIZE               16384
+#define BACKPTR_VEC_SIZE        4096
+#define FULL_GC_INTERVAL        10
 
 typedef struct heap {
   struct heap *next;
@@ -72,6 +74,13 @@ static val heap_min_bound, heap_max_bound;
 
 int gc_enabled = 1;
 
+#if CONFIG_GEN_GC
+static val backptr[BACKPTR_VEC_SIZE];
+static int backptr_idx;
+static int partial_gc_count;
+static int full;
+#endif
+
 #if EXTRA_DEBUGGING
 static val break_obj;
 #endif
@@ -165,6 +174,9 @@ val make_obj(void)
       if (opt_vg_debug)
         VALGRIND_MAKE_MEM_UNDEFINED(ret, sizeof *ret);
 #endif
+#if CONFIG_GEN_GC
+      ret->t.gen = 0;
+#endif
       return ret;
     }
 
@@ -472,6 +484,16 @@ void gc(void)
 {
   val gc_stack_top = nil;
 
+#if CONFIG_GEN_GC
+  if (backptr_idx && ++partial_gc_count == FULL_GC_INTERVAL) {
+    full = 1;
+    partial_gc_count = 0;
+    backptr_idx = 0;
+  } else {
+    full = 0;
+  }
+#endif
+
   if (gc_enabled) {
     mach_context_t mc;
     save_context(mc);
@@ -513,6 +535,34 @@ int gc_is_reachable(val obj)
   return (t & REACHABLE) != 0;
 }
 
+#if CONFIG_GEN_GC
+
+val gc_set(val *ptr, val val)
+{
+  if (!is_ptr(val))
+    goto out;
+  if (val->t.gen != 0)
+    goto out;
+
+  backptr[backptr_idx++] = val;
+out:
+  *ptr = val;
+
+  if (backptr_idx == BACKPTR_VEC_SIZE)
+    gc();
+
+  return val;
+}
+
+void gc_mutated(val obj)
+{
+  backptr[backptr_idx++] = obj;
+  if (backptr_idx == BACKPTR_VEC_SIZE)
+    gc();
+}
+
+#endif
+
 /*
  * Useful functions for gdb'ing.
  */