From c9eb61256110df932e56019e46556ca719c8010d Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Sat, 22 Mar 2014 20:03:05 +0900
Subject: [PATCH 1/4] do variable closing operation not in OP_CALL but in
 OP_RET

---
 include/picrin/proc.h |  1 +
 src/codegen.c         | 18 ++++++++++++++----
 src/gc.c              |  1 -
 src/vm.c              | 24 +++++++++++++++++++-----
 4 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/include/picrin/proc.h b/include/picrin/proc.h
index 0b937537..34c12654 100644
--- a/include/picrin/proc.h
+++ b/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 {
diff --git a/src/codegen.c b/src/codegen.c
index 9946fa4b..4de20f75 100644
--- a/src/codegen.c
+++ b/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 *
diff --git a/src/gc.c b/src/gc.c
index ec830474..6681b793 100644
--- a/src/gc.c
+++ b/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: {
diff --git a/src/vm.c b/src/vm.c
index 079b35c0..ca3a11b8 100644
--- a/src/vm.c
+++ b/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));
-        for (i = 0; i < ci->env->valuec; ++i) {
-          ci->env->values[i] = ci->fp[irep->cv_tbl[i]];
-        }
+        ci->env->values = ci->fp + irep->argc + irep->localc;
 
 	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:

From cac31845d03808acf285112c7aadd416bc48f060 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Sat, 22 Mar 2014 20:06:20 +0900
Subject: [PATCH 2/4] cv_tbl is no longer used

---
 include/picrin/irep.h | 5 -----
 src/codegen.c         | 5 -----
 src/gc.c              | 1 -
 3 files changed, 11 deletions(-)

diff --git a/include/picrin/irep.h b/include/picrin/irep.h
index 36607c3a..de0b8e80 100644
--- a/include/picrin/irep.h
+++ b/include/picrin/irep.h
@@ -62,7 +62,6 @@ struct pic_irep {
   PIC_OBJECT_HEADER
   pic_code *code;
   int argc, localc, capturec;
-  unsigned *cv_tbl;
   bool varg;
   struct pic_irep **irep;
   pic_value *pool;
@@ -189,10 +188,6 @@ pic_dump_irep(struct pic_irep *irep)
 
   printf("## irep %p\n", (void *)irep);
   printf("[clen = %zd, argc = %d, localc = %d, capturec = %d]\n", irep->clen, irep->argc, irep->localc, irep->capturec);
-  printf(":: cv_tbl\n");
-  for (i = 0; i < (unsigned)irep->capturec; ++i) {
-    printf(": %d -> %d\n", irep->cv_tbl[i], i);
-  }
   for (i = 0; i < irep->clen; ++i) {
     printf("%02x ", i);
     pic_dump_code(irep->code[i]);
diff --git a/src/codegen.c b/src/codegen.c
index 4de20f75..bc022512 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -817,8 +817,6 @@ typedef struct codegen_context {
   bool varg;
   /* rest args variable is counted as a local */
   xvect args, locals, captures;
-  /* closed variable table */
-  unsigned *cv_tbl;
   /* actual bit code sequence */
   pic_code *code;
   size_t clen, ccapa;
@@ -905,7 +903,6 @@ create_cv_table(pic_state *pic, codegen_context *cxt)
   }
 
   /* closed variables */
-  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);
     if ((n = xh_get_int(regs, *var)->val) <= cxt->args.size) {
@@ -918,7 +915,6 @@ create_cv_table(pic_state *pic, codegen_context *cxt)
       cxt->code[cxt->clen].insn = OP_PUSHNONE;
       cxt->clen++;
     }
-    cxt->cv_tbl[i] = n;
   }
 
   xh_destroy(regs);
@@ -979,7 +975,6 @@ pop_codegen_context(codegen_state *state)
   irep->argc = state->cxt->args.size + 1;
   irep->localc = state->cxt->locals.size;
   irep->capturec = state->cxt->captures.size;
-  irep->cv_tbl = state->cxt->cv_tbl;
   irep->code = pic_realloc(pic, state->cxt->code, sizeof(pic_code) * state->cxt->clen);
   irep->clen = state->cxt->clen;
   irep->irep = pic_realloc(pic, state->cxt->irep, sizeof(struct pic_irep *) * state->cxt->ilen);
diff --git a/src/gc.c b/src/gc.c
index 6681b793..424ea87c 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -634,7 +634,6 @@ gc_finalize_object(pic_state *pic, struct pic_object *obj)
   case PIC_TT_IREP: {
     struct pic_irep *irep = (struct pic_irep *)obj;
     pic_free(pic, irep->code);
-    pic_free(pic, irep->cv_tbl);
     pic_free(pic, irep->irep);
     pic_free(pic, irep->pool);
     break;

From 1b6f1db1c0611e0f6deb1447f9136ba0c42e55a3 Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Sat, 22 Mar 2014 20:36:50 +0900
Subject: [PATCH 3/4] s/create_cv_table/create_activation/g

---
 src/codegen.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/codegen.c b/src/codegen.c
index bc022512..a91c790e 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -881,7 +881,7 @@ destroy_codegen_state(codegen_state *state)
 }
 
 static void
-create_cv_table(pic_state *pic, codegen_context *cxt)
+create_activation(codegen_context *cxt)
 {
   size_t i, n;
   xhash *regs;
@@ -890,7 +890,6 @@ create_cv_table(pic_state *pic, codegen_context *cxt)
 
   regs = xh_new_int();
 
-  /* number local variables */
   offset = 1;
   for (i = 0; i < cxt->args.size; ++i) {
     var = xv_get(&cxt->args, i);
@@ -902,7 +901,6 @@ create_cv_table(pic_state *pic, codegen_context *cxt)
     xh_put_int(regs, *var, i + offset);
   }
 
-  /* closed variables */
   for (i = 0; i < cxt->captures.size; ++i) {
     var = xv_get(&cxt->captures, i);
     if ((n = xh_get_int(regs, *var)->val) <= cxt->args.size) {
@@ -959,7 +957,7 @@ push_codegen_context(codegen_state *state, pic_value args, pic_value locals, boo
 
   state->cxt = cxt;
 
-  create_cv_table(pic, cxt);
+  create_activation(cxt);
 }
 
 static struct pic_irep *

From 4a1809a9c5eb3325bf39fb93fdacfa7862a4b8ae Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Sun, 23 Mar 2014 12:18:41 +0900
Subject: [PATCH 4/4] get access to captured local variables with
 OP_LREF/OP_LSET

---
 src/codegen.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/src/codegen.c b/src/codegen.c
index a91c790e..26b68e2e 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -1053,7 +1053,6 @@ codegen(codegen_state *state, pic_value obj)
     pic_sym name;
     int depth;
 
-  CREF:
     depth = pic_int(pic_list_ref(pic, obj, 1));
     name  = pic_sym(pic_list_ref(pic, obj, 2));
     cxt->code[cxt->clen].insn = OP_CREF;
@@ -1063,11 +1062,14 @@ codegen(codegen_state *state, pic_value obj)
     return;
   } else if (sym == state->sLREF) {
     pic_sym name;
+    int i;
 
     name = pic_sym(pic_list_ref(pic, obj, 1));
-    if (index_capture(state, name, 0) != -1) {
-      obj = pic_list3(pic, pic_sym_value(state->sCREF), pic_int_value(0), pic_sym_value(name));
-      goto CREF;
+    if ((i = index_capture(state, name, 0)) != -1) {
+      cxt->code[cxt->clen].insn = OP_LREF;
+      cxt->code[cxt->clen].u.i = i + cxt->args.size + cxt->locals.size + 1;
+      cxt->clen++;
+      return;
     }
     cxt->code[cxt->clen].insn = OP_LREF;
     cxt->code[cxt->clen].u.i = index_local(state, name);
@@ -1094,7 +1096,6 @@ codegen(codegen_state *state, pic_value obj)
       pic_sym name;
       int depth;
 
-    CSET:
       depth = pic_int(pic_list_ref(pic, var, 1));
       name  = pic_sym(pic_list_ref(pic, var, 2));
       cxt->code[cxt->clen].insn = OP_CSET;
@@ -1107,11 +1108,16 @@ codegen(codegen_state *state, pic_value obj)
     }
     else if (type == state->sLREF) {
       pic_sym name;
+      int i;
 
       name = pic_sym(pic_list_ref(pic, var, 1));
-      if (index_capture(state, name, 0) != -1) {
-        var = pic_list3(pic, pic_sym_value(state->sCREF), pic_int_value(0), pic_sym_value(name));
-        goto CSET;
+      if ((i = index_capture(state, name, 0)) != -1) {
+        cxt->code[cxt->clen].insn = OP_LSET;
+        cxt->code[cxt->clen].u.i = i + cxt->args.size + cxt->locals.size + 1;
+        cxt->clen++;
+        cxt->code[cxt->clen].insn = OP_PUSHNONE;
+        cxt->clen++;
+        return;
       }
       cxt->code[cxt->clen].insn = OP_LSET;
       cxt->code[cxt->clen].u.i = index_local(state, name);