do variable closing operation not in OP_CALL but in OP_RET

include/picrin/proc.h

@@ -20,6 +20,7 @@ struct pic_env {
   pic_value *values;
   int valuec;
   struct pic_env *up;
+  pic_value storage[];
 };
 
 struct pic_proc {

src/codegen.c

@@ -885,7 +885,7 @@ destroy_codegen_state(codegen_state *state)
 static void
 create_cv_table(pic_state *pic, codegen_context *cxt)
 {
-  size_t i;
+  size_t i, n;
   xhash *regs;
   pic_sym *var;
   size_t offset;
@@ -908,7 +908,17 @@ create_cv_table(pic_state *pic, codegen_context *cxt)
   cxt->cv_tbl = pic_calloc(pic, cxt->captures.size, sizeof(unsigned));
   for (i = 0; i < cxt->captures.size; ++i) {
     var = xv_get(&cxt->captures, i);
-    cxt->cv_tbl[i] = xh_get_int(regs, *var)->val;
+    if ((n = xh_get_int(regs, *var)->val) <= cxt->args.size) {
+      /* copy arguments to capture variable area */
+      cxt->code[cxt->clen].insn = OP_LREF;
+      cxt->code[cxt->clen].u.i = n;
+      cxt->clen++;
+    } else {
+      /* otherwise, just extend the stack */
+      cxt->code[cxt->clen].insn = OP_PUSHNONE;
+      cxt->clen++;
+    }
+    cxt->cv_tbl[i] = n;
   }
 
   xh_destroy(regs);
@@ -939,8 +949,6 @@ push_codegen_context(codegen_state *state, pic_value args, pic_value locals, boo
     xv_push(&cxt->captures, &pic_sym(var));
   }
 
-  create_cv_table(pic, cxt);
-
   cxt->code = pic_calloc(pic, PIC_ISEQ_SIZE, sizeof(pic_code));
   cxt->clen = 0;
   cxt->ccapa = PIC_ISEQ_SIZE;
@@ -954,6 +962,8 @@ push_codegen_context(codegen_state *state, pic_value args, pic_value locals, boo
   cxt->pcapa = PIC_POOL_SIZE;
 
   state->cxt = cxt;
+
+  create_cv_table(pic, cxt);
 }
 
 static struct pic_irep *

src/gc.c

@@ -580,7 +580,6 @@ gc_finalize_object(pic_state *pic, struct pic_object *obj)
     break;
   }
   case PIC_TT_ENV: {
-    pic_free(pic, ((struct pic_env *)obj)->values);
     break;
   }
   case PIC_TT_PROC: {

src/vm.c

@@ -424,6 +424,19 @@ pic_defvar(pic_state *pic, const char *name, pic_value init)
   pic_define(pic, name, pic_obj_value(pic_wrap_var(pic, var)));
 }
 
+static void
+vm_tear_off(pic_state *pic)
+{
+  struct pic_env *env;
+  int i;
+
+  env = pic->ci->env;
+  for (i = 0; i < env->valuec; ++i) {
+    env->storage[i] = env->values[i];
+  }
+  env->values = env->storage;
+}
+
 pic_value
 pic_apply_argv(pic_state *pic, struct pic_proc *proc, size_t argc, ...)
 {
@@ -707,13 +720,10 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value argv)
 	}
 
 	/* prepare env */
-        ci->env = (struct pic_env *)pic_obj_alloc(pic, sizeof(struct pic_env), PIC_TT_ENV);
+        ci->env = (struct pic_env *)pic_obj_alloc(pic, offsetof(struct pic_env, storage) + sizeof(pic_value) * irep->capturec, PIC_TT_ENV);
         ci->env->up = proc->env;
         ci->env->valuec = irep->capturec;
-        ci->env->values = pic_calloc(pic, ci->env->valuec, sizeof(pic_value));
+        ci->env->values = ci->fp + irep->argc + irep->localc;
-        for (i = 0; i < ci->env->valuec; ++i) {
-          ci->env->values[i] = ci->fp[irep->cv_tbl[i]];
-        }
 
 	pic->ip = irep->code;
 	pic_gc_arena_restore(pic, ai);
@@ -725,6 +735,8 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value argv)
       pic_value *argv;
       pic_callinfo *ci;
 
+      vm_tear_off(pic);
+
       if (c.u.i == -1) {
         pic->sp += pic->ci[1].retc - 1;
         c.u.i = pic->ci[1].retc + 1;
@@ -753,6 +765,8 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value argv)
 	goto L_STOP;
       }
 
+      vm_tear_off(pic);
+
       pic->ci->retc = c.u.i;
 
     L_RET: