* 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, 11 insertions, 9 deletions

diff --git a/lib.c b/lib.c
index 8e17893c..436a47ee 100644
--- a/lib.c
+++ b/lib.c
@@ -249,13 +249,13 @@ val *car_l(val cons)
 {
   switch (type(cons)) {
   case CONS:
-    return loc(cons->c.car);
+    return &cons->c.car;
   case LCONS:
     if (cons->lc.func) {
       funcall1(cons->lc.func, cons);
       cons->lc.func = nil;
     }
-    return loc(cons->lc.car);
+    return &cons->lc.car;
   default:
     type_mismatch(lit("~s is not a cons"), cons, nao);
   }
@@ -265,13 +265,13 @@ val *cdr_l(val cons)
 {
   switch (type(cons)) {
   case CONS:
-    return loc(cons->c.cdr);
+    return &cons->c.cdr;
   case LCONS:
     if (cons->lc.func) {
       funcall1(cons->lc.func, cons);
       cons->lc.func = nil;
     }
-    return loc(cons->lc.cdr);
+    return &cons->lc.cdr;
   default:
     type_mismatch(lit("~s is not a cons"), cons, nao);
   }
@@ -361,7 +361,9 @@ val pop(val *plist)
 
 val push(val value, val *plist)
 {
-  return *plist = cons(value, *plist);
+  /* TODO: doing set here is suboptimal since
+     it is often used for just a local var. */
+  return set(*plist, cons(value, *plist));
 }
 
 val copy_list(val list)
@@ -2249,7 +2251,7 @@ val intern(val str, val package)
   } else {
     val newsym = make_sym(str);
     newsym->s.package = package;
-    return *place = newsym;
+    return set(*place, newsym);
   }
 }
 
@@ -3096,7 +3098,7 @@ val *vecref_l(val vec, val ind)
   cnum index = c_num(ind);
   cnum len = c_num(length_vec(vec));
   range_bug_unless (index >= 0 && index < len);
-  return loc(vec->v.vec[index]);
+  return vec->v.vec + index;
 }
 
 val vec_push(val vec, val item)
@@ -3618,7 +3620,7 @@ val *acons_new_l(val key, val *new_p, val *list)
     return cdr_l(existing);
   } else {
     val nc = cons(key, nil);
-    *list = cons(nc, *list);
+    set(*list, cons(nc, *list));
     if (new_p)
       *new_p = t;
     return cdr_l(nc);
@@ -3647,7 +3649,7 @@ val *aconsq_new_l(val key, val *new_p, val *list)
     return cdr_l(existing);
   } else {
     val nc = cons(key, nil);
-    *list = cons(nc, *list);
+    set(*list, cons(nc, *list));
     if (new_p)
       *new_p = t;
     return cdr_l(nc);