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[Guile-commits] GNU Guile branch, master, updated. release_1-9-1-6-g476e


From: Andy Wingo
Subject: [Guile-commits] GNU Guile branch, master, updated. release_1-9-1-6-g476e357
Date: Thu, 23 Jul 2009 15:22:48 +0000

This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU Guile".

http://git.savannah.gnu.org/cgit/guile.git/commit/?id=476e35728136b2d504855f3e2e4922ed72a41101

The branch, master has been updated
       via  476e35728136b2d504855f3e2e4922ed72a41101 (commit)
       via  57ab0671d71bd6e485784f46b6dea4708661082d (commit)
       via  20d47c3915c1b910e683d4b010b91c48047d6251 (commit)
       via  66d3e9a32c2da4eedb3f316e0dcffe92e6631f87 (commit)
       via  8d90b356560b9cf54300ff9eabf4675acb650e03 (commit)
       via  a5cfddd560ca21205c8b0417413253d94f3e9b93 (commit)
      from  3b0b6bc1dd2eb24405ad8e75889df0874f879892 (commit)

Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
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- Log -----------------------------------------------------------------
commit 476e35728136b2d504855f3e2e4922ed72a41101
Author: Andy Wingo <address@hidden>
Date:   Thu Jul 23 16:50:47 2009 +0200

    remove all mentions of "external" from the compiler and related code
    
    With this, GHIL is effectively bitrotten. I need to port the ECMAScript
    compiler to tree-il, then I'll remove it.
    
    * module/language/assembly.scm (byte-length):
    * module/language/assembly/compile-bytecode.scm (write-bytecode):
    * module/language/assembly/decompile-bytecode.scm (decode-load-program):
    * module/language/assembly/disassemble.scm (disassemble-load-program):
      (disassemble-free-vars, code-annotation):
    * module/language/glil.scm (<glil-program>, <glil-local>)
      (<glil-exteral>, parse-glil, unparse-glil):
    * module/language/glil/compile-assembly.scm (make-meta):
      (compile-assembly, glil->assembly):
    * module/language/glil/decompile-assembly.scm (decompile-toplevel):
      (decompile-load-program):
    * module/language/objcode/spec.scm (decompile-value):
    * module/language/tree-il/compile-glil.scm (flatten-lambda):
    * module/system/vm/frame.scm (frame-binding-ref):
      (frame-binding-set!):
    * module/system/vm/program.scm (binding:boxed?):
    * module/system/vm/trace.scm (trace-next):
    * test-suite/tests/asm-to-bytecode.test ("compiler"):
    * test-suite/tests/tree-il.test: Remove all mentions of "external", and
      of <glil-local>. Docs updates will come soon.

commit 57ab0671d71bd6e485784f46b6dea4708661082d
Author: Andy Wingo <address@hidden>
Date:   Thu Jul 23 14:36:22 2009 +0200

    rename "closure-ref" to "free-ref"; s/vars/variables/ in some names
    
    * libguile/programs.h:
    * libguile/programs.c: (SCM_PROGRAM_FREE_VARIABLES): Rename from
      SCM_PROGRAM_FREE_VARS. Callers changed.
    * libguile/programs.c (scm_make_program): Rename arg to
      "free_variables".
      (scm_program_free_variables): Rename from program-free-vars.
    
    * libguile/vm-engine.h:
    * libguile/vm-engine.c (VM_CHECK_FREE_VARIABLES): Rename from
      VM_CHECK_CLOSURE.
      (vm_engine, CACHE_PROGRAM): Rename closure and closure_count to free_vars 
and
      free_vars_vount.
    
    * libguile/vm-i-system.c (FREE_VARIABLE_REF): Rename from CLOSURE_REF.
      (free-ref, free-boxed-ref, free-boxed-set): Rename from closure-ref,
      closure-boxed-ref, closure-boxed-set.
      (make-closure): Renamed from make-closure2.
    
    * module/language/glil/compile-assembly.scm (glil->assembly): Hack to
      never write out the the old "make-closure" instruction. Will fix
      better later. Change to emit free-ref etc instead of closure-ref.
    
    * module/language/tree-il/compile-glil.scm (flatten): Emit make-closure
      instead of make-closure2, now that the old make-closure is gone.
    
    * module/system/vm/program.scm (system): Rename program-free-vars to
      program-free-variables.
    
    * test-suite/tests/tree-il.test ("lambda"): Update for make-closure.

commit 20d47c3915c1b910e683d4b010b91c48047d6251
Author: Andy Wingo <address@hidden>
Date:   Thu Jul 23 17:12:10 2009 +0200

    remove "externals" from the vm
    
    * libguile/frames.c (scm_frame_external_link): Removed.
    * libguile/frames.h: No need to have the "external link" in the stack
      frame -- update macros to take the new situation into account.
    
    * libguile/objcodes.h (struct scm_objcode): Rename the nexts field to
      "unused". In the future we can use it for nlocs, I think.
      (SCM_OBJCODE_NEXTS): removed.
    
    * libguile/programs.h:
    * libguile/programs.c (scm_make_program): Expect the third argument to
      be a vector of free variables, not a list of free variables.
      SCM_BOOL_F indicates no free variables, not SCM_EOL.
      (program_mark): Adapt.
      (scm_program_arity): No more nexts.
      (scm_program_free_vars): Replaces scm_program_externals.
    
    * libguile/vm-engine.c (VM_CHECK_EXTERNAL)
      (vm_engine): No need for the "external" var.
    * libguile/vm-engine.h (CACHE_PROGRAM): Update for SCM_PROGRAM_FREE_VARS
      instead of SCM_PROGRAM_EXTERNALS.
      (NEW_FRAME): Update for new frame size, and no need to cons up
      externals. Yay :)
    
    * libguile/vm-i-loader.c (load-program): Update for scm_make_program.
    
    * libguile/vm-i-system.c (external-ref, external-set): No more.
      (make-closure): No more.
      (goto/args): No need to re-cons externals here. Update for new stack
      frame size.
      (mv-call, return, return/values): Update for new frame size. No need
      to reinstate externals on return.
    
    * libguile/vm.c (really_make_boot_program, scm_load_compiled_with_vm):
      Update for scm_make_program.
    * module/language/objcode/spec.scm (objcode-env-externals): Treat '() as
      #f, for the externals. Need to clean this up later...
    * module/system/vm/program.scm (arity:nexts): Remove. Rename
      program-external to program-free-vars.

commit 66d3e9a32c2da4eedb3f316e0dcffe92e6631f87
Author: Andy Wingo <address@hidden>
Date:   Thu Jul 23 17:00:56 2009 +0200

    compile lexical variable access and closure creation to the new ops
    
    * module/language/glil.scm (<glil>): New GLIL type, <glil-lexical>,
      which will subsume other lexical types.
    * module/language/glil/compile-assembly.scm: Compile <glil-lexical>.
      (make-open-binding): Change the interpretation of the second argument
      -- instead of indicating an "external" var, it now indicates a boxed
      var.
      (open-binding): Adapt to new glil-bind format.
    * module/language/tree-il/analyze.scm: Add a lot more docs.
      (analyze-lexicals): Change the allocation algorithm and output format
      to allow the tree-il->glil compiler to capture free variables
      appropriately and to reference bound variables in boxes if necessary.
      Amply documented.
    
    * module/language/tree-il/compile-glil.scm (compile-glil): Compile
      lexical variable access to <glil-lexical>. Emit variable capture and
      closure creation code here, instead of leaving that task to the
      GLIL->assembly compiler.
    
    * test-suite/tests/tree-il.test: Update expected code emission.

commit 8d90b356560b9cf54300ff9eabf4675acb650e03
Author: Andy Wingo <address@hidden>
Date:   Sun Jul 19 19:48:26 2009 +0200

    vm support for display closures
    
    * libguile/vm-i-system.c (box, empty-box): Boxing values and storing
      them in local variables.
      (local-boxed-ref, local-boxed-set): A combination of local-ref then
      variable-ref/set.
      (make-closure2, closure-ref, closure-boxed-ref, closure-boxed-set):
      New ops. The idea is to migrate Guile over to using flat dispay
      closures. See the paper "Three Implementation Models for Scheme" by
      Kent Dybvig for more details; this is the "stack-based" model.
    
    * libguile/vm-engine.c:
    * libguile/vm-engine.h: Add the necessary infrastructure to keep track
      of a "closure" variable, like our "externals" in semantics, but
      minimal, flat, and O(1) in implementation.

commit a5cfddd560ca21205c8b0417413253d94f3e9b93
Author: Andy Wingo <address@hidden>
Date:   Sun Jul 19 19:02:30 2009 +0200

    renumber vm ops (objcode cookie bumped)
    
    * libguile/objcodes.c (OBJCODE_COOKIE): Bump.
    
    * libguile/vm-i-loader.c:
    * libguile/vm-i-scheme.c:
    * libguile/vm-i-system.c: Renumber instructions, so I can have a bit
      more space to work.

-----------------------------------------------------------------------

Summary of changes:
 libguile/frames.c                               |   12 +-
 libguile/frames.h                               |   17 +-
 libguile/objcodes.c                             |    2 +-
 libguile/objcodes.h                             |    3 +-
 libguile/programs.c                             |   52 +---
 libguile/programs.h                             |    9 +-
 libguile/vm-engine.c                            |   21 +-
 libguile/vm-engine.h                            |   64 ++--
 libguile/vm-i-loader.c                          |   24 +-
 libguile/vm-i-scheme.c                          |  136 ++++----
 libguile/vm-i-system.c                          |  317 +++++++++++---------
 libguile/vm.c                                   |    6 +-
 module/language/assembly.scm                    |    4 +-
 module/language/assembly/compile-bytecode.scm   |    5 +-
 module/language/assembly/decompile-bytecode.scm |    6 +-
 module/language/assembly/disassemble.scm        |   40 +--
 module/language/glil.scm                        |   54 +---
 module/language/glil/compile-assembly.scm       |  142 ++++-----
 module/language/glil/decompile-assembly.scm     |   20 +-
 module/language/objcode/spec.scm                |   17 +-
 module/language/tree-il/analyze.scm             |  382 +++++++++++++----------
 module/language/tree-il/compile-glil.scm        |  164 +++++-----
 module/system/repl/command.scm                  |    1 -
 module/system/vm/frame.scm                      |   47 ++--
 module/system/vm/program.scm                    |   17 +-
 module/system/vm/trace.scm                      |    5 +-
 test-suite/tests/asm-to-bytecode.test           |   12 +-
 test-suite/tests/tree-il.test                   |  202 ++++++------
 28 files changed, 897 insertions(+), 884 deletions(-)

diff --git a/libguile/frames.c b/libguile/frames.c
index 76552f5..e89184d 100644
--- a/libguile/frames.c
+++ b/libguile/frames.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2001 Free Software Foundation, Inc.
+/* Copyright (C) 2001, 2009 Free Software Foundation, Inc.
  * 
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -222,16 +222,6 @@ SCM_DEFINE (scm_vm_frame_dynamic_link, 
"vm-frame-dynamic-link", 1, 0, 0,
 }
 #undef FUNC_NAME
 
-SCM_DEFINE (scm_vm_frame_external_link, "vm-frame-external-link", 1, 0, 0,
-           (SCM frame),
-           "")
-#define FUNC_NAME s_scm_vm_frame_external_link
-{
-  SCM_VALIDATE_VM_FRAME (1, frame);
-  return SCM_FRAME_EXTERNAL_LINK (SCM_VM_FRAME_FP (frame));
-}
-#undef FUNC_NAME
-
 SCM_DEFINE (scm_vm_frame_stack, "vm-frame-stack", 1, 0, 0,
            (SCM frame),
            "")
diff --git a/libguile/frames.h b/libguile/frames.h
index 99623fb..1d8a30f 100644
--- a/libguile/frames.h
+++ b/libguile/frames.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2001 Free Software Foundation, Inc.
+/* Copyright (C) 2001, 2009 Free Software Foundation, Inc.
  * * 
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -30,12 +30,11 @@
 /* VM Frame Layout
    ---------------
 
-   |                  | <- fp + bp->nargs + bp->nlocs + 4
+   |                  | <- fp + bp->nargs + bp->nlocs + 3
    +------------------+    = SCM_FRAME_UPPER_ADDRESS (fp)
    | Return address   |
    | MV return address|
-   | Dynamic link     |
-   | External link    | <- fp + bp->nargs + bp->nlocs
+   | Dynamic link     | <- fp + bp->nargs + bp->blocs
    | Local variable 1 |    = SCM_FRAME_DATA_ADDRESS (fp)
    | Local variable 0 | <- fp + bp->nargs
    | Argument 1       |
@@ -51,21 +50,20 @@
 #define SCM_FRAME_DATA_ADDRESS(fp)                             \
   (fp + SCM_PROGRAM_DATA (SCM_FRAME_PROGRAM (fp))->nargs       \
       + SCM_PROGRAM_DATA (SCM_FRAME_PROGRAM (fp))->nlocs)
-#define SCM_FRAME_UPPER_ADDRESS(fp)    (SCM_FRAME_DATA_ADDRESS (fp) + 4)
+#define SCM_FRAME_UPPER_ADDRESS(fp)    (SCM_FRAME_DATA_ADDRESS (fp) + 3)
 #define SCM_FRAME_LOWER_ADDRESS(fp)    (fp - 1)
 
 #define SCM_FRAME_BYTE_CAST(x)         ((scm_byte_t *) SCM_UNPACK (x))
 #define SCM_FRAME_STACK_CAST(x)                ((SCM *) SCM_UNPACK (x))
 
 #define SCM_FRAME_RETURN_ADDRESS(fp)                           \
-  (SCM_FRAME_BYTE_CAST (SCM_FRAME_DATA_ADDRESS (fp)[3]))
-#define SCM_FRAME_MV_RETURN_ADDRESS(fp)                                \
   (SCM_FRAME_BYTE_CAST (SCM_FRAME_DATA_ADDRESS (fp)[2]))
+#define SCM_FRAME_MV_RETURN_ADDRESS(fp)                                \
+  (SCM_FRAME_BYTE_CAST (SCM_FRAME_DATA_ADDRESS (fp)[1]))
 #define SCM_FRAME_DYNAMIC_LINK(fp)                             \
-  (SCM_FRAME_STACK_CAST (SCM_FRAME_DATA_ADDRESS (fp)[1]))
+  (SCM_FRAME_STACK_CAST (SCM_FRAME_DATA_ADDRESS (fp)[0]))
 #define SCM_FRAME_SET_DYNAMIC_LINK(fp, dl)             \
   ((SCM_FRAME_DATA_ADDRESS (fp)[1])) = (SCM)(dl);
-#define SCM_FRAME_EXTERNAL_LINK(fp)    (SCM_FRAME_DATA_ADDRESS (fp)[0])
 #define SCM_FRAME_VARIABLE(fp,i)       fp[i]
 #define SCM_FRAME_PROGRAM(fp)          fp[-1]
 
@@ -106,7 +104,6 @@ SCM_API SCM scm_vm_frame_local_set_x (SCM frame, SCM index, 
SCM val);
 SCM_API SCM scm_vm_frame_return_address (SCM frame);
 SCM_API SCM scm_vm_frame_mv_return_address (SCM frame);
 SCM_API SCM scm_vm_frame_dynamic_link (SCM frame);
-SCM_API SCM scm_vm_frame_external_link (SCM frame);
 SCM_API SCM scm_vm_frame_stack (SCM frame);
 
 SCM_API SCM scm_c_vm_frame_prev (SCM frame);
diff --git a/libguile/objcodes.c b/libguile/objcodes.c
index a210553..5a43edb 100644
--- a/libguile/objcodes.c
+++ b/libguile/objcodes.c
@@ -50,7 +50,7 @@
 
 /* The objcode magic header.  */
 #define OBJCODE_COOKIE                                         \
-  "GOOF-0.6-" OBJCODE_ENDIANNESS "-" OBJCODE_WORD_SIZE "---"
+  "GOOF-0.7-" OBJCODE_ENDIANNESS "-" OBJCODE_WORD_SIZE "---"
 
 /* The length of the header must be a multiple of 8 bytes.  */
 verify (((sizeof (OBJCODE_COOKIE) - 1) & 7) == 0);
diff --git a/libguile/objcodes.h b/libguile/objcodes.h
index e9b1cdb..6727e23 100644
--- a/libguile/objcodes.h
+++ b/libguile/objcodes.h
@@ -26,7 +26,7 @@ struct scm_objcode {
   scm_t_uint8 nargs;
   scm_t_uint8 nrest;
   scm_t_uint8 nlocs;
-  scm_t_uint8 nexts;
+  scm_t_uint8 unused;
   scm_t_uint32 len;             /* the maximum index of base[] */
   scm_t_uint32 metalen;         /* well, i lie. this many bytes at the end of
                                    base[] for metadata */
@@ -49,7 +49,6 @@ SCM_API scm_t_bits scm_tc16_objcode;
 #define SCM_OBJCODE_NARGS(x)   (SCM_OBJCODE_DATA (x)->nargs)
 #define SCM_OBJCODE_NREST(x)   (SCM_OBJCODE_DATA (x)->nrest)
 #define SCM_OBJCODE_NLOCS(x)   (SCM_OBJCODE_DATA (x)->nlocs)
-#define SCM_OBJCODE_NEXTS(x)   (SCM_OBJCODE_DATA (x)->nexts)
 #define SCM_OBJCODE_BASE(x)    (SCM_OBJCODE_DATA (x)->base)
 
 #define SCM_OBJCODE_IS_MMAP(x) (SCM_SMOB_FLAGS (x) & SCM_F_OBJCODE_IS_MMAP)
diff --git a/libguile/programs.c b/libguile/programs.c
index 892b677..5c43ac5 100644
--- a/libguile/programs.c
+++ b/libguile/programs.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2001 Free Software Foundation, Inc.
+/* Copyright (C) 2001, 2009 Free Software Foundation, Inc.
  * 
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -36,7 +36,7 @@ scm_t_bits scm_tc16_program;
 static SCM write_program = SCM_BOOL_F;
 
 SCM_DEFINE (scm_make_program, "make-program", 1, 2, 0,
-           (SCM objcode, SCM objtable, SCM external),
+           (SCM objcode, SCM objtable, SCM free_variables),
            "")
 #define FUNC_NAME s_scm_make_program
 {
@@ -45,18 +45,12 @@ SCM_DEFINE (scm_make_program, "make-program", 1, 2, 0,
     objtable = SCM_BOOL_F;
   else if (scm_is_true (objtable))
     SCM_VALIDATE_VECTOR (2, objtable);
-  if (SCM_UNLIKELY (SCM_UNBNDP (external)))
-    external = SCM_EOL;
-  else
-    /* FIXME: currently this test is quite expensive (can be 2-3% of total
-       execution time in programs that make many closures). We could remove it,
-       yes, but we'd get much better gains if we used some other method, like
-       just capturing the variables that we need instead of all heap-allocated
-       variables. Dunno. Keeping the check for now, as it's a user-callable
-       function, and inlining the op in the vm's make-closure operation. */
-    SCM_VALIDATE_LIST (3, external);
-
-  SCM_RETURN_NEWSMOB3 (scm_tc16_program, objcode, objtable, external);
+  if (SCM_UNLIKELY (SCM_UNBNDP (free_variables)))
+    free_variables = SCM_BOOL_F;
+  else if (free_variables != SCM_BOOL_F)
+    SCM_VALIDATE_VECTOR (3, free_variables);
+
+  SCM_RETURN_NEWSMOB3 (scm_tc16_program, objcode, objtable, free_variables);
 }
 #undef FUNC_NAME
 
@@ -65,8 +59,8 @@ program_mark (SCM obj)
 {
   if (scm_is_true (SCM_PROGRAM_OBJTABLE (obj)))
     scm_gc_mark (SCM_PROGRAM_OBJTABLE (obj));
-  if (!scm_is_null (SCM_PROGRAM_EXTERNALS (obj)))
-    scm_gc_mark (SCM_PROGRAM_EXTERNALS (obj));
+  if (scm_is_true (SCM_PROGRAM_FREE_VARIABLES (obj)))
+    scm_gc_mark (SCM_PROGRAM_FREE_VARIABLES (obj));
   return SCM_PROGRAM_OBJCODE (obj);
 }
 
@@ -151,10 +145,9 @@ SCM_DEFINE (scm_program_arity, "program-arity", 1, 0, 0,
   SCM_VALIDATE_PROGRAM (1, program);
 
   p = SCM_PROGRAM_DATA (program);
-  return scm_list_4 (SCM_I_MAKINUM (p->nargs),
+  return scm_list_3 (SCM_I_MAKINUM (p->nargs),
                     SCM_I_MAKINUM (p->nrest),
-                    SCM_I_MAKINUM (p->nlocs),
-                    SCM_I_MAKINUM (p->nexts));
+                    SCM_I_MAKINUM (p->nlocs));
 }
 #undef FUNC_NAME
 
@@ -191,7 +184,7 @@ SCM_DEFINE (scm_program_meta, "program-meta", 1, 0, 0,
 
   metaobj = scm_objcode_meta (SCM_PROGRAM_OBJCODE (program));
   if (scm_is_true (metaobj))
-    return scm_make_program (metaobj, SCM_BOOL_F, SCM_EOL);
+    return scm_make_program (metaobj, SCM_BOOL_F, SCM_BOOL_F);
   else
     return SCM_BOOL_F;
 }
@@ -300,26 +293,13 @@ scm_c_program_source (SCM program, size_t ip)
   return source; /* (addr . (filename . (line . column))) */
 }
 
-SCM_DEFINE (scm_program_external, "program-external", 1, 0, 0,
+SCM_DEFINE (scm_program_free_variables, "program-free-variables", 1, 0, 0,
            (SCM program),
            "")
-#define FUNC_NAME s_scm_program_external
-{
-  SCM_VALIDATE_PROGRAM (1, program);
-  return SCM_PROGRAM_EXTERNALS (program);
-}
-#undef FUNC_NAME
-
-SCM_DEFINE (scm_program_external_set_x, "program-external-set!", 2, 0, 0,
-           (SCM program, SCM external),
-           "Modify the list of closure variables of @var{program} (for "
-           "debugging purposes).")
-#define FUNC_NAME s_scm_program_external_set_x
+#define FUNC_NAME s_scm_program_free_variables
 {
   SCM_VALIDATE_PROGRAM (1, program);
-  SCM_VALIDATE_LIST (2, external);
-  SCM_PROGRAM_EXTERNALS (program) = external;
-  return SCM_UNSPECIFIED;
+  return SCM_PROGRAM_FREE_VARIABLES (program);
 }
 #undef FUNC_NAME
 
diff --git a/libguile/programs.h b/libguile/programs.h
index 16a1550..040e8ea 100644
--- a/libguile/programs.h
+++ b/libguile/programs.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2001 Free Software Foundation, Inc.
+/* Copyright (C) 2001, 2009 Free Software Foundation, Inc.
  * 
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -35,12 +35,12 @@ SCM_API scm_t_bits scm_tc16_program;
 #define SCM_PROGRAM_P(x)       (SCM_SMOB_PREDICATE (scm_tc16_program, x))
 #define SCM_PROGRAM_OBJCODE(x) (SCM_SMOB_OBJECT (x))
 #define SCM_PROGRAM_OBJTABLE(x)        (SCM_SMOB_OBJECT_2 (x))
-#define SCM_PROGRAM_EXTERNALS(x) (SCM_SMOB_OBJECT_3 (x))
+#define SCM_PROGRAM_FREE_VARIABLES(x) (SCM_SMOB_OBJECT_3 (x))
 #define SCM_PROGRAM_DATA(x)    (SCM_OBJCODE_DATA (SCM_PROGRAM_OBJCODE (x)))
 #define SCM_VALIDATE_PROGRAM(p,x) SCM_MAKE_VALIDATE (p, x, PROGRAM_P)
 #define SCM_PROGRAM_IS_BOOT(x) (SCM_SMOB_FLAGS (x) & SCM_F_PROGRAM_IS_BOOT)
 
-SCM_API SCM scm_make_program (SCM objcode, SCM objtable, SCM externals);
+SCM_API SCM scm_make_program (SCM objcode, SCM objtable, SCM free_variables);
 
 SCM_API SCM scm_program_p (SCM obj);
 SCM_API SCM scm_program_base (SCM program);
@@ -53,8 +53,7 @@ SCM_API SCM scm_program_properties (SCM program);
 SCM_API SCM scm_program_name (SCM program);
 SCM_API SCM scm_program_objects (SCM program);
 SCM_API SCM scm_program_module (SCM program);
-SCM_API SCM scm_program_external (SCM program);
-SCM_API SCM scm_program_external_set_x (SCM program, SCM external);
+SCM_API SCM scm_program_free_variables (SCM program);
 SCM_API SCM scm_program_objcode (SCM program);
 
 SCM_API SCM scm_c_program_source (SCM program, size_t ip);
diff --git a/libguile/vm-engine.c b/libguile/vm-engine.c
index 90cf697..98a6e49 100644
--- a/libguile/vm-engine.c
+++ b/libguile/vm-engine.c
@@ -21,14 +21,14 @@
 #if (VM_ENGINE == SCM_VM_REGULAR_ENGINE)
 #define VM_USE_HOOKS           0       /* Various hooks */
 #define VM_USE_CLOCK           0       /* Bogoclock */
-#define VM_CHECK_EXTERNAL      1       /* Check external link */
 #define VM_CHECK_OBJECT         1       /* Check object table */
+#define VM_CHECK_FREE_VARIABLES 1       /* Check free variable access */
 #define VM_PUSH_DEBUG_FRAMES    0       /* Push frames onto the evaluator 
debug stack */
 #elif (VM_ENGINE == SCM_VM_DEBUG_ENGINE)
 #define VM_USE_HOOKS           1
 #define VM_USE_CLOCK           1
-#define VM_CHECK_EXTERNAL      1
 #define VM_CHECK_OBJECT         1
+#define VM_CHECK_FREE_VARIABLES 1
 #define VM_PUSH_DEBUG_FRAMES    1
 #else
 #error unknown debug engine VM_ENGINE
@@ -47,7 +47,8 @@ VM_NAME (struct scm_vm *vp, SCM program, SCM *argv, int nargs)
 
   /* Cache variables */
   struct scm_objcode *bp = NULL;       /* program base pointer */
-  SCM external = SCM_EOL;              /* external environment */
+  SCM *free_vars = NULL;                /* free variables */
+  size_t free_vars_count = 0;           /* length of FREE_VARS */
   SCM *objects = NULL;                 /* constant objects */
   size_t object_count = 0;              /* length of OBJECTS */
   SCM *stack_base = vp->stack_base;    /* stack base address */
@@ -226,16 +227,16 @@ VM_NAME (struct scm_vm *vp, SCM program, SCM *argv, int 
nargs)
     goto vm_error;
 #endif
 
-#if VM_CHECK_EXTERNAL
-  vm_error_external:
-    err_msg  = scm_from_locale_string ("VM: Invalid external access");
+#if VM_CHECK_OBJECT
+  vm_error_object:
+    err_msg = scm_from_locale_string ("VM: Invalid object table access");
     finish_args = SCM_EOL;
     goto vm_error;
 #endif
 
-#if VM_CHECK_OBJECT
-  vm_error_object:
-    err_msg = scm_from_locale_string ("VM: Invalid object table access");
+#if VM_CHECK_FREE_VARIABLES
+  vm_error_free_variable:
+    err_msg = scm_from_locale_string ("VM: Invalid free variable access");
     finish_args = SCM_EOL;
     goto vm_error;
 #endif
@@ -252,8 +253,8 @@ VM_NAME (struct scm_vm *vp, SCM program, SCM *argv, int 
nargs)
 
 #undef VM_USE_HOOKS
 #undef VM_USE_CLOCK
-#undef VM_CHECK_EXTERNAL
 #undef VM_CHECK_OBJECT
+#undef VM_CHECK_FREE_VARIABLE
 #undef VM_PUSH_DEBUG_FRAMES
 
 /*
diff --git a/libguile/vm-engine.h b/libguile/vm-engine.h
index d684979..15ebb53 100644
--- a/libguile/vm-engine.h
+++ b/libguile/vm-engine.h
@@ -117,6 +117,16 @@
   vp->fp = fp;                                 \
 }
 
+/* FIXME */
+#define ASSERT_VARIABLE(x)                                              \
+  do { if (!SCM_VARIABLEP (x)) { SYNC_REGISTER (); abort(); }           \
+  } while (0)
+#define ASSERT_BOUND_VARIABLE(x)                                        \
+  do { ASSERT_VARIABLE (x);                                             \
+    if (SCM_VARIABLE_REF (x) == SCM_UNDEFINED)                          \
+      { SYNC_REGISTER (); abort(); }                                    \
+  } while (0)
+
 #ifdef VM_ENABLE_PARANOID_ASSERTIONS
 #define CHECK_IP() \
   do { if (ip < bp->base || ip - bp->base > bp->len) abort (); } while (0)
@@ -128,11 +138,7 @@
 #define ASSERT_BOUND(x)
 #endif
 
-/* Get a local copy of the program's "object table" (i.e. the vector of
-   external bindings that are referenced by the program), initialized by
-   `load-program'.  */
-/* XXX:  We could instead use the "simple vector macros", thus not having to
-   call `scm_vector_writable_elements ()' and the likes.  */
+/* Cache the object table and free variables.  */
 #define CACHE_PROGRAM()                                                        
\
 {                                                                      \
   if (bp != SCM_PROGRAM_DATA (program)) {                               \
@@ -145,6 +151,19 @@
       object_count = 0;                                                 \
     }                                                                   \
   }                                                                     \
+  {                                                                     \
+    SCM c = SCM_PROGRAM_FREE_VARIABLES (program);                       \
+    if (SCM_I_IS_VECTOR (c))                                            \
+      {                                                                 \
+        free_vars = SCM_I_VECTOR_WELTS (c);                             \
+        free_vars_count = SCM_I_VECTOR_LENGTH (c);                      \
+      }                                                                 \
+    else                                                                \
+      {                                                                 \
+        free_vars = NULL;                                               \
+        free_vars_count = 0;                                            \
+      }                                                                 \
+  }                                                                     \
 }
 
 #define SYNC_BEFORE_GC()                       \
@@ -162,14 +181,6 @@
  * Error check
  */
 
-#undef CHECK_EXTERNAL
-#if VM_CHECK_EXTERNAL
-#define CHECK_EXTERNAL(e) \
-  do { if (SCM_UNLIKELY (!SCM_CONSP (e))) goto vm_error_external; } while (0)
-#else
-#define CHECK_EXTERNAL(e)
-#endif
-
 /* Accesses to a program's object table.  */
 #if VM_CHECK_OBJECT
 #define CHECK_OBJECT(_num) \
@@ -178,6 +189,13 @@
 #define CHECK_OBJECT(_num)
 #endif
 
+#if VM_CHECK_FREE_VARIABLES
+#define CHECK_FREE_VARIABLE(_num) \
+  do { if (SCM_UNLIKELY ((_num) >= free_vars_count)) goto 
vm_error_free_variable; } while (0)
+#else
+#define CHECK_FREE_VARIABLE(_num)
+#endif
+
 
 /*
  * Hooks
@@ -376,7 +394,7 @@ do {                                                \
   /* New registers */                           \
   fp = sp - bp->nargs + 1;                      \
   data = SCM_FRAME_DATA_ADDRESS (fp);           \
-  sp = data + 3;                                \
+  sp = data + 2;                                \
   CHECK_OVERFLOW ();                           \
   stack_base = sp;                             \
   ip = bp->base;                               \
@@ -386,23 +404,11 @@ do {                                              \
     data[-i] = SCM_UNDEFINED;                   \
                                                \
   /* Set frame data */                         \
-  data[3] = (SCM)ra;                            \
-  data[2] = 0x0;                                \
-  data[1] = (SCM)dl;                            \
-                                                \
-  /* Postpone initializing external vars,       \
-     because if the CONS causes a GC, we        \
-     want the stack marker to see the data      \
-     array formatted as expected. */            \
-  data[0] = SCM_UNDEFINED;                      \
-  external = SCM_PROGRAM_EXTERNALS (fp[-1]);    \
-  for (i = 0; i < bp->nexts; i++)               \
-    CONS (external, SCM_UNDEFINED, external);   \
-  data[0] = external;                           \
+  data[2] = (SCM)ra;                            \
+  data[1] = 0x0;                                \
+  data[0] = (SCM)dl;                            \
 }
 
-#define CACHE_EXTERNAL() external = fp[bp->nargs + bp->nlocs]
-
 /*
   Local Variables:
   c-file-style: "gnu"
diff --git a/libguile/vm-i-loader.c b/libguile/vm-i-loader.c
index 86d0fc4..9ae49ed 100644
--- a/libguile/vm-i-loader.c
+++ b/libguile/vm-i-loader.c
@@ -20,7 +20,7 @@
 
 /* This file is included in vm_engine.c */
 
-VM_DEFINE_LOADER (59, load_unsigned_integer, "load-unsigned-integer")
+VM_DEFINE_LOADER (80, load_unsigned_integer, "load-unsigned-integer")
 {
   size_t len;
 
@@ -38,7 +38,7 @@ VM_DEFINE_LOADER (59, load_unsigned_integer, 
"load-unsigned-integer")
     SCM_MISC_ERROR ("load-unsigned-integer: not implemented yet", SCM_EOL);
 }
 
-VM_DEFINE_LOADER (60, load_integer, "load-integer")
+VM_DEFINE_LOADER (81, load_integer, "load-integer")
 {
   size_t len;
 
@@ -56,7 +56,7 @@ VM_DEFINE_LOADER (60, load_integer, "load-integer")
     SCM_MISC_ERROR ("load-integer: not implemented yet", SCM_EOL);
 }
 
-VM_DEFINE_LOADER (61, load_number, "load-number")
+VM_DEFINE_LOADER (82, load_number, "load-number")
 {
   size_t len;
 
@@ -69,7 +69,7 @@ VM_DEFINE_LOADER (61, load_number, "load-number")
   NEXT;
 }
 
-VM_DEFINE_LOADER (62, load_string, "load-string")
+VM_DEFINE_LOADER (83, load_string, "load-string")
 {
   size_t len;
   FETCH_LENGTH (len);
@@ -80,7 +80,7 @@ VM_DEFINE_LOADER (62, load_string, "load-string")
   NEXT;
 }
 
-VM_DEFINE_LOADER (63, load_symbol, "load-symbol")
+VM_DEFINE_LOADER (84, load_symbol, "load-symbol")
 {
   size_t len;
   FETCH_LENGTH (len);
@@ -90,7 +90,7 @@ VM_DEFINE_LOADER (63, load_symbol, "load-symbol")
   NEXT;
 }
 
-VM_DEFINE_LOADER (64, load_keyword, "load-keyword")
+VM_DEFINE_LOADER (85, load_keyword, "load-keyword")
 {
   size_t len;
   FETCH_LENGTH (len);
@@ -100,7 +100,7 @@ VM_DEFINE_LOADER (64, load_keyword, "load-keyword")
   NEXT;
 }
 
-VM_DEFINE_LOADER (65, load_program, "load-program")
+VM_DEFINE_LOADER (86, load_program, "load-program")
 {
   scm_t_uint32 len;
   SCM objs, objcode;
@@ -114,14 +114,14 @@ VM_DEFINE_LOADER (65, load_program, "load-program")
   objcode = scm_c_make_objcode_slice (SCM_PROGRAM_OBJCODE (fp[-1]), ip);
   len = sizeof (struct scm_objcode) + SCM_OBJCODE_TOTAL_LEN (objcode);
 
-  PUSH (scm_make_program (objcode, objs, SCM_EOL));
+  PUSH (scm_make_program (objcode, objs, SCM_BOOL_F));
 
   ip += len;
 
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (66, link_now, "link-now", 0, 1, 1)
+VM_DEFINE_INSTRUCTION (87, link_now, "link-now", 0, 1, 1)
 {
   SCM what;
   POP (what);
@@ -130,7 +130,7 @@ VM_DEFINE_INSTRUCTION (66, link_now, "link-now", 0, 1, 1)
   NEXT;
 }
 
-VM_DEFINE_LOADER (67, define, "define")
+VM_DEFINE_LOADER (88, define, "define")
 {
   SCM sym;
   size_t len;
@@ -145,7 +145,7 @@ VM_DEFINE_LOADER (67, define, "define")
   NEXT;
 }
 
-VM_DEFINE_LOADER (68, load_array, "load-array")
+VM_DEFINE_LOADER (89, load_array, "load-array")
 {
   SCM type, shape;
   size_t len;
@@ -163,7 +163,7 @@ VM_DEFINE_LOADER (68, load_array, "load-array")
   "start from top of buffer and renumber 'VM_DEFINE_FOO (\n' sequences"
   (interactive "")
   (save-excursion
-    (let ((counter 59)) (goto-char (point-min))
+    (let ((counter 79)) (goto-char (point-min))
       (while (re-search-forward "^VM_DEFINE_[^ ]+ (\\([^,]+\\)," (point-max) t)
         (replace-match
          (number-to-string (setq counter (1+ counter)))
diff --git a/libguile/vm-i-scheme.c b/libguile/vm-i-scheme.c
index 42f8bac..dce9b5f 100644
--- a/libguile/vm-i-scheme.c
+++ b/libguile/vm-i-scheme.c
@@ -29,43 +29,43 @@
 
 #define RETURN(x)      do { *sp = x; NEXT; } while (0)
 
-VM_DEFINE_FUNCTION (80, not, "not", 1)
+VM_DEFINE_FUNCTION (100, not, "not", 1)
 {
   ARGS1 (x);
   RETURN (SCM_BOOL (SCM_FALSEP (x)));
 }
 
-VM_DEFINE_FUNCTION (81, not_not, "not-not", 1)
+VM_DEFINE_FUNCTION (101, not_not, "not-not", 1)
 {
   ARGS1 (x);
   RETURN (SCM_BOOL (!SCM_FALSEP (x)));
 }
 
-VM_DEFINE_FUNCTION (82, eq, "eq?", 2)
+VM_DEFINE_FUNCTION (102, eq, "eq?", 2)
 {
   ARGS2 (x, y);
   RETURN (SCM_BOOL (SCM_EQ_P (x, y)));
 }
 
-VM_DEFINE_FUNCTION (83, not_eq, "not-eq?", 2)
+VM_DEFINE_FUNCTION (103, not_eq, "not-eq?", 2)
 {
   ARGS2 (x, y);
   RETURN (SCM_BOOL (!SCM_EQ_P (x, y)));
 }
 
-VM_DEFINE_FUNCTION (84, nullp, "null?", 1)
+VM_DEFINE_FUNCTION (104, nullp, "null?", 1)
 {
   ARGS1 (x);
   RETURN (SCM_BOOL (SCM_NULLP (x)));
 }
 
-VM_DEFINE_FUNCTION (85, not_nullp, "not-null?", 1)
+VM_DEFINE_FUNCTION (105, not_nullp, "not-null?", 1)
 {
   ARGS1 (x);
   RETURN (SCM_BOOL (!SCM_NULLP (x)));
 }
 
-VM_DEFINE_FUNCTION (86, eqv, "eqv?", 2)
+VM_DEFINE_FUNCTION (106, eqv, "eqv?", 2)
 {
   ARGS2 (x, y);
   if (SCM_EQ_P (x, y))
@@ -76,7 +76,7 @@ VM_DEFINE_FUNCTION (86, eqv, "eqv?", 2)
   RETURN (scm_eqv_p (x, y));
 }
 
-VM_DEFINE_FUNCTION (87, equal, "equal?", 2)
+VM_DEFINE_FUNCTION (107, equal, "equal?", 2)
 {
   ARGS2 (x, y);
   if (SCM_EQ_P (x, y))
@@ -87,13 +87,13 @@ VM_DEFINE_FUNCTION (87, equal, "equal?", 2)
   RETURN (scm_equal_p (x, y));
 }
 
-VM_DEFINE_FUNCTION (88, pairp, "pair?", 1)
+VM_DEFINE_FUNCTION (108, pairp, "pair?", 1)
 {
   ARGS1 (x);
   RETURN (SCM_BOOL (SCM_CONSP (x)));
 }
 
-VM_DEFINE_FUNCTION (89, listp, "list?", 1)
+VM_DEFINE_FUNCTION (109, listp, "list?", 1)
 {
   ARGS1 (x);
   RETURN (SCM_BOOL (scm_ilength (x) >= 0));
@@ -104,7 +104,7 @@ VM_DEFINE_FUNCTION (89, listp, "list?", 1)
  * Basic data
  */
 
-VM_DEFINE_FUNCTION (90, cons, "cons", 2)
+VM_DEFINE_FUNCTION (110, cons, "cons", 2)
 {
   ARGS2 (x, y);
   CONS (x, x, y);
@@ -117,21 +117,21 @@ VM_DEFINE_FUNCTION (90, cons, "cons", 2)
       goto vm_error_not_a_pair;                 \
     }
   
-VM_DEFINE_FUNCTION (91, car, "car", 1)
+VM_DEFINE_FUNCTION (111, car, "car", 1)
 {
   ARGS1 (x);
   VM_VALIDATE_CONS (x);
   RETURN (SCM_CAR (x));
 }
 
-VM_DEFINE_FUNCTION (92, cdr, "cdr", 1)
+VM_DEFINE_FUNCTION (112, cdr, "cdr", 1)
 {
   ARGS1 (x);
   VM_VALIDATE_CONS (x);
   RETURN (SCM_CDR (x));
 }
 
-VM_DEFINE_INSTRUCTION (93, set_car, "set-car!", 0, 2, 0)
+VM_DEFINE_INSTRUCTION (113, set_car, "set-car!", 0, 2, 0)
 {
   SCM x, y;
   POP (y);
@@ -141,7 +141,7 @@ VM_DEFINE_INSTRUCTION (93, set_car, "set-car!", 0, 2, 0)
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (94, set_cdr, "set-cdr!", 0, 2, 0)
+VM_DEFINE_INSTRUCTION (114, set_cdr, "set-cdr!", 0, 2, 0)
 {
   SCM x, y;
   POP (y);
@@ -166,27 +166,27 @@ VM_DEFINE_INSTRUCTION (94, set_cdr, "set-cdr!", 0, 2, 0)
   RETURN (srel (x, y));                                         \
 }
 
-VM_DEFINE_FUNCTION (95, ee, "ee?", 2)
+VM_DEFINE_FUNCTION (115, ee, "ee?", 2)
 {
   REL (==, scm_num_eq_p);
 }
 
-VM_DEFINE_FUNCTION (96, lt, "lt?", 2)
+VM_DEFINE_FUNCTION (116, lt, "lt?", 2)
 {
   REL (<, scm_less_p);
 }
 
-VM_DEFINE_FUNCTION (97, le, "le?", 2)
+VM_DEFINE_FUNCTION (117, le, "le?", 2)
 {
   REL (<=, scm_leq_p);
 }
 
-VM_DEFINE_FUNCTION (98, gt, "gt?", 2)
+VM_DEFINE_FUNCTION (118, gt, "gt?", 2)
 {
   REL (>, scm_gr_p);
 }
 
-VM_DEFINE_FUNCTION (99, ge, "ge?", 2)
+VM_DEFINE_FUNCTION (119, ge, "ge?", 2)
 {
   REL (>=, scm_geq_p);
 }
@@ -210,45 +210,45 @@ VM_DEFINE_FUNCTION (99, ge, "ge?", 2)
   RETURN (SFUNC (x, y));                               \
 }
 
-VM_DEFINE_FUNCTION (100, add, "add", 2)
+VM_DEFINE_FUNCTION (120, add, "add", 2)
 {
   FUNC2 (+, scm_sum);
 }
 
-VM_DEFINE_FUNCTION (101, sub, "sub", 2)
+VM_DEFINE_FUNCTION (121, sub, "sub", 2)
 {
   FUNC2 (-, scm_difference);
 }
 
-VM_DEFINE_FUNCTION (102, mul, "mul", 2)
+VM_DEFINE_FUNCTION (122, mul, "mul", 2)
 {
   ARGS2 (x, y);
   SYNC_REGISTER ();
   RETURN (scm_product (x, y));
 }
 
-VM_DEFINE_FUNCTION (103, div, "div", 2)
+VM_DEFINE_FUNCTION (123, div, "div", 2)
 {
   ARGS2 (x, y);
   SYNC_REGISTER ();
   RETURN (scm_divide (x, y));
 }
 
-VM_DEFINE_FUNCTION (104, quo, "quo", 2)
+VM_DEFINE_FUNCTION (124, quo, "quo", 2)
 {
   ARGS2 (x, y);
   SYNC_REGISTER ();
   RETURN (scm_quotient (x, y));
 }
 
-VM_DEFINE_FUNCTION (105, rem, "rem", 2)
+VM_DEFINE_FUNCTION (125, rem, "rem", 2)
 {
   ARGS2 (x, y);
   SYNC_REGISTER ();
   RETURN (scm_remainder (x, y));
 }
 
-VM_DEFINE_FUNCTION (106, mod, "mod", 2)
+VM_DEFINE_FUNCTION (126, mod, "mod", 2)
 {
   ARGS2 (x, y);
   SYNC_REGISTER ();
@@ -259,7 +259,7 @@ VM_DEFINE_FUNCTION (106, mod, "mod", 2)
 /*
  * GOOPS support
  */
-VM_DEFINE_FUNCTION (107, slot_ref, "slot-ref", 2)
+VM_DEFINE_FUNCTION (127, slot_ref, "slot-ref", 2)
 {
   size_t slot;
   ARGS2 (instance, idx);
@@ -267,7 +267,7 @@ VM_DEFINE_FUNCTION (107, slot_ref, "slot-ref", 2)
   RETURN (SCM_PACK (SCM_STRUCT_DATA (instance) [slot]));
 }
 
-VM_DEFINE_INSTRUCTION (108, slot_set, "slot-set", 0, 3, 0)
+VM_DEFINE_INSTRUCTION (128, slot_set, "slot-set", 0, 3, 0)
 {
   SCM instance, idx, val;
   size_t slot;
@@ -279,7 +279,7 @@ VM_DEFINE_INSTRUCTION (108, slot_set, "slot-set", 0, 3, 0)
   NEXT;
 }
 
-VM_DEFINE_FUNCTION (109, vector_ref, "vector-ref", 2)
+VM_DEFINE_FUNCTION (129, vector_ref, "vector-ref", 2)
 {
   long i = 0;
   ARGS2 (vect, idx);
@@ -292,7 +292,7 @@ VM_DEFINE_FUNCTION (109, vector_ref, "vector-ref", 2)
     RETURN (scm_vector_ref (vect, idx));
 }
 
-VM_DEFINE_INSTRUCTION (110, vector_set, "vector-set", 0, 3, 0)
+VM_DEFINE_INSTRUCTION (130, vector_set, "vector-set", 0, 3, 0)
 {
   long i = 0;
   SCM vect, idx, val;
@@ -325,21 +325,21 @@ VM_DEFINE_INSTRUCTION (110, vector_set, "vector-set", 0, 
3, 0)
   }                                                                     \
 }
 
-VM_DEFINE_FUNCTION (111, bv_u16_ref, "bv-u16-ref", 3)
+VM_DEFINE_FUNCTION (131, bv_u16_ref, "bv-u16-ref", 3)
 BV_REF_WITH_ENDIANNESS (u16, u16)
-VM_DEFINE_FUNCTION (112, bv_s16_ref, "bv-s16-ref", 3)
+VM_DEFINE_FUNCTION (132, bv_s16_ref, "bv-s16-ref", 3)
 BV_REF_WITH_ENDIANNESS (s16, s16)
-VM_DEFINE_FUNCTION (113, bv_u32_ref, "bv-u32-ref", 3)
+VM_DEFINE_FUNCTION (133, bv_u32_ref, "bv-u32-ref", 3)
 BV_REF_WITH_ENDIANNESS (u32, u32)
-VM_DEFINE_FUNCTION (114, bv_s32_ref, "bv-s32-ref", 3)
+VM_DEFINE_FUNCTION (134, bv_s32_ref, "bv-s32-ref", 3)
 BV_REF_WITH_ENDIANNESS (s32, s32)
-VM_DEFINE_FUNCTION (115, bv_u64_ref, "bv-u64-ref", 3)
+VM_DEFINE_FUNCTION (135, bv_u64_ref, "bv-u64-ref", 3)
 BV_REF_WITH_ENDIANNESS (u64, u64)
-VM_DEFINE_FUNCTION (116, bv_s64_ref, "bv-s64-ref", 3)
+VM_DEFINE_FUNCTION (136, bv_s64_ref, "bv-s64-ref", 3)
 BV_REF_WITH_ENDIANNESS (s64, s64)
-VM_DEFINE_FUNCTION (117, bv_f32_ref, "bv-f32-ref", 3)
+VM_DEFINE_FUNCTION (137, bv_f32_ref, "bv-f32-ref", 3)
 BV_REF_WITH_ENDIANNESS (f32, ieee_single)
-VM_DEFINE_FUNCTION (118, bv_f64_ref, "bv-f64-ref", 3)
+VM_DEFINE_FUNCTION (138, bv_f64_ref, "bv-f64-ref", 3)
 BV_REF_WITH_ENDIANNESS (f64, ieee_double)
 
 #undef BV_REF_WITH_ENDIANNESS
@@ -392,26 +392,26 @@ BV_REF_WITH_ENDIANNESS (f64, ieee_double)
     RETURN (scm_bytevector_##fn_stem##_native_ref (bv, idx));           \
 }
 
-VM_DEFINE_FUNCTION (119, bv_u8_ref, "bv-u8-ref", 2)
+VM_DEFINE_FUNCTION (139, bv_u8_ref, "bv-u8-ref", 2)
 BV_FIXABLE_INT_REF (u8, u8, uint8, 1)
-VM_DEFINE_FUNCTION (120, bv_s8_ref, "bv-s8-ref", 2)
+VM_DEFINE_FUNCTION (140, bv_s8_ref, "bv-s8-ref", 2)
 BV_FIXABLE_INT_REF (s8, s8, int8, 1)
-VM_DEFINE_FUNCTION (121, bv_u16_native_ref, "bv-u16-native-ref", 2)
+VM_DEFINE_FUNCTION (141, bv_u16_native_ref, "bv-u16-native-ref", 2)
 BV_FIXABLE_INT_REF (u16, u16_native, uint16, 2)
-VM_DEFINE_FUNCTION (122, bv_s16_native_ref, "bv-s16-native-ref", 2)
+VM_DEFINE_FUNCTION (142, bv_s16_native_ref, "bv-s16-native-ref", 2)
 BV_FIXABLE_INT_REF (s16, s16_native, int16, 2)
-VM_DEFINE_FUNCTION (123, bv_u32_native_ref, "bv-u32-native-ref", 2)
+VM_DEFINE_FUNCTION (143, bv_u32_native_ref, "bv-u32-native-ref", 2)
 /* FIXME: u32 is always a fixnum on 64-bit builds */
 BV_INT_REF (u32, uint32, 4)
-VM_DEFINE_FUNCTION (124, bv_s32_native_ref, "bv-s32-native-ref", 2)
+VM_DEFINE_FUNCTION (144, bv_s32_native_ref, "bv-s32-native-ref", 2)
 BV_INT_REF (s32, int32, 4)
-VM_DEFINE_FUNCTION (125, bv_u64_native_ref, "bv-u64-native-ref", 2)
+VM_DEFINE_FUNCTION (145, bv_u64_native_ref, "bv-u64-native-ref", 2)
 BV_INT_REF (u64, uint64, 8)
-VM_DEFINE_FUNCTION (126, bv_s64_native_ref, "bv-s64-native-ref", 2)
+VM_DEFINE_FUNCTION (146, bv_s64_native_ref, "bv-s64-native-ref", 2)
 BV_INT_REF (s64, int64, 8)
-VM_DEFINE_FUNCTION (127, bv_f32_native_ref, "bv-f32-native-ref", 2)
+VM_DEFINE_FUNCTION (147, bv_f32_native_ref, "bv-f32-native-ref", 2)
 BV_FLOAT_REF (f32, ieee_single, float, 4)
-VM_DEFINE_FUNCTION (128, bv_f64_native_ref, "bv-f64-native-ref", 2)
+VM_DEFINE_FUNCTION (148, bv_f64_native_ref, "bv-f64-native-ref", 2)
 BV_FLOAT_REF (f64, ieee_double, double, 8)
 
 #undef BV_FIXABLE_INT_REF
@@ -433,21 +433,21 @@ BV_FLOAT_REF (f64, ieee_double, double, 8)
   }                                                                     \
 }
 
-VM_DEFINE_INSTRUCTION (129, bv_u16_set, "bv-u16-set", 0, 4, 0)
+VM_DEFINE_INSTRUCTION (149, bv_u16_set, "bv-u16-set", 0, 4, 0)
 BV_SET_WITH_ENDIANNESS (u16, u16)
-VM_DEFINE_INSTRUCTION (130, bv_s16_set, "bv-s16-set", 0, 4, 0)
+VM_DEFINE_INSTRUCTION (150, bv_s16_set, "bv-s16-set", 0, 4, 0)
 BV_SET_WITH_ENDIANNESS (s16, s16)
-VM_DEFINE_INSTRUCTION (131, bv_u32_set, "bv-u32-set", 0, 4, 0)
+VM_DEFINE_INSTRUCTION (151, bv_u32_set, "bv-u32-set", 0, 4, 0)
 BV_SET_WITH_ENDIANNESS (u32, u32)
-VM_DEFINE_INSTRUCTION (132, bv_s32_set, "bv-s32-set", 0, 4, 0)
+VM_DEFINE_INSTRUCTION (152, bv_s32_set, "bv-s32-set", 0, 4, 0)
 BV_SET_WITH_ENDIANNESS (s32, s32)
-VM_DEFINE_INSTRUCTION (133, bv_u64_set, "bv-u64-set", 0, 4, 0)
+VM_DEFINE_INSTRUCTION (153, bv_u64_set, "bv-u64-set", 0, 4, 0)
 BV_SET_WITH_ENDIANNESS (u64, u64)
-VM_DEFINE_INSTRUCTION (134, bv_s64_set, "bv-s64-set", 0, 4, 0)
+VM_DEFINE_INSTRUCTION (154, bv_s64_set, "bv-s64-set", 0, 4, 0)
 BV_SET_WITH_ENDIANNESS (s64, s64)
-VM_DEFINE_INSTRUCTION (135, bv_f32_set, "bv-f32-set", 0, 4, 0)
+VM_DEFINE_INSTRUCTION (155, bv_f32_set, "bv-f32-set", 0, 4, 0)
 BV_SET_WITH_ENDIANNESS (f32, ieee_single)
-VM_DEFINE_INSTRUCTION (136, bv_f64_set, "bv-f64-set", 0, 4, 0)
+VM_DEFINE_INSTRUCTION (156, bv_f64_set, "bv-f64-set", 0, 4, 0)
 BV_SET_WITH_ENDIANNESS (f64, ieee_double)
 
 #undef BV_SET_WITH_ENDIANNESS
@@ -500,26 +500,26 @@ BV_SET_WITH_ENDIANNESS (f64, ieee_double)
   NEXT;                                                                 \
 }
 
-VM_DEFINE_INSTRUCTION (137, bv_u8_set, "bv-u8-set", 0, 3, 0)
+VM_DEFINE_INSTRUCTION (157, bv_u8_set, "bv-u8-set", 0, 3, 0)
 BV_FIXABLE_INT_SET (u8, u8, uint8, 0, SCM_T_UINT8_MAX, 1)
-VM_DEFINE_INSTRUCTION (138, bv_s8_set, "bv-s8-set", 0, 3, 0)
+VM_DEFINE_INSTRUCTION (158, bv_s8_set, "bv-s8-set", 0, 3, 0)
 BV_FIXABLE_INT_SET (s8, s8, int8, SCM_T_INT8_MIN, SCM_T_INT8_MAX, 1)
-VM_DEFINE_INSTRUCTION (139, bv_u16_native_set, "bv-u16-native-set", 0, 3, 0)
+VM_DEFINE_INSTRUCTION (159, bv_u16_native_set, "bv-u16-native-set", 0, 3, 0)
 BV_FIXABLE_INT_SET (u16, u16_native, uint16, 0, SCM_T_UINT16_MAX, 2)
-VM_DEFINE_INSTRUCTION (140, bv_s16_native_set, "bv-s16-native-set", 0, 3, 0)
+VM_DEFINE_INSTRUCTION (160, bv_s16_native_set, "bv-s16-native-set", 0, 3, 0)
 BV_FIXABLE_INT_SET (s16, s16_native, int16, SCM_T_INT16_MIN, SCM_T_INT16_MAX, 
2)
-VM_DEFINE_INSTRUCTION (141, bv_u32_native_set, "bv-u32-native-set", 0, 3, 0)
+VM_DEFINE_INSTRUCTION (161, bv_u32_native_set, "bv-u32-native-set", 0, 3, 0)
 /* FIXME: u32 is always a fixnum on 64-bit builds */
 BV_INT_SET (u32, uint32, 4)
-VM_DEFINE_INSTRUCTION (142, bv_s32_native_set, "bv-s32-native-set", 0, 3, 0)
+VM_DEFINE_INSTRUCTION (162, bv_s32_native_set, "bv-s32-native-set", 0, 3, 0)
 BV_INT_SET (s32, int32, 4)
-VM_DEFINE_INSTRUCTION (143, bv_u64_native_set, "bv-u64-native-set", 0, 3, 0)
+VM_DEFINE_INSTRUCTION (163, bv_u64_native_set, "bv-u64-native-set", 0, 3, 0)
 BV_INT_SET (u64, uint64, 8)
-VM_DEFINE_INSTRUCTION (144, bv_s64_native_set, "bv-s64-native-set", 0, 3, 0)
+VM_DEFINE_INSTRUCTION (164, bv_s64_native_set, "bv-s64-native-set", 0, 3, 0)
 BV_INT_SET (s64, int64, 8)
-VM_DEFINE_INSTRUCTION (145, bv_f32_native_set, "bv-f32-native-set", 0, 3, 0)
+VM_DEFINE_INSTRUCTION (165, bv_f32_native_set, "bv-f32-native-set", 0, 3, 0)
 BV_FLOAT_SET (f32, ieee_single, float, 4)
-VM_DEFINE_INSTRUCTION (146, bv_f64_native_set, "bv-f64-native-set", 0, 3, 0)
+VM_DEFINE_INSTRUCTION (166, bv_f64_native_set, "bv-f64-native-set", 0, 3, 0)
 BV_FLOAT_SET (f64, ieee_double, double, 8)
 
 #undef BV_FIXABLE_INT_SET
@@ -531,7 +531,7 @@ BV_FLOAT_SET (f64, ieee_double, double, 8)
   "start from top of buffer and renumber 'VM_DEFINE_FOO (\n' sequences"
   (interactive "")
   (save-excursion
-    (let ((counter 79)) (goto-char (point-min))
+    (let ((counter 99)) (goto-char (point-min))
       (while (re-search-forward "^VM_DEFINE_[^ ]+ (\\([^,]+\\)," (point-max) t)
         (replace-match
          (number-to-string (setq counter (1+ counter)))
diff --git a/libguile/vm-i-system.c b/libguile/vm-i-system.c
index d55d6e2..e12217e 100644
--- a/libguile/vm-i-system.c
+++ b/libguile/vm-i-system.c
@@ -139,7 +139,7 @@ VM_DEFINE_INSTRUCTION (13, make_int16, "make-int16", 2, 0, 
1)
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (55, make_int64, "make-int64", 8, 0, 1)
+VM_DEFINE_INSTRUCTION (14, make_int64, "make-int64", 8, 0, 1)
 {
   scm_t_uint64 v = 0;
   v += FETCH ();
@@ -154,7 +154,7 @@ VM_DEFINE_INSTRUCTION (55, make_int64, "make-int64", 8, 0, 
1)
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (56, make_uint64, "make-uint64", 8, 0, 1)
+VM_DEFINE_INSTRUCTION (15, make_uint64, "make-uint64", 8, 0, 1)
 {
   scm_t_uint64 v = 0;
   v += FETCH ();
@@ -169,13 +169,13 @@ VM_DEFINE_INSTRUCTION (56, make_uint64, "make-uint64", 8, 
0, 1)
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (14, make_char8, "make-char8", 1, 0, 1)
+VM_DEFINE_INSTRUCTION (16, make_char8, "make-char8", 1, 0, 1)
 {
   PUSH (SCM_MAKE_CHAR (FETCH ()));
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (15, list, "list", 2, -1, 1)
+VM_DEFINE_INSTRUCTION (17, list, "list", 2, -1, 1)
 {
   unsigned h = FETCH ();
   unsigned l = FETCH ();
@@ -184,7 +184,7 @@ VM_DEFINE_INSTRUCTION (15, list, "list", 2, -1, 1)
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (16, vector, "vector", 2, -1, 1)
+VM_DEFINE_INSTRUCTION (18, vector, "vector", 2, -1, 1)
 {
   unsigned h = FETCH ();
   unsigned l = FETCH ();
@@ -202,19 +202,19 @@ VM_DEFINE_INSTRUCTION (16, vector, "vector", 2, -1, 1)
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (17, list_mark, "list-mark", 0, 0, 0)
+VM_DEFINE_INSTRUCTION (19, list_mark, "list-mark", 0, 0, 0)
 {
   POP_LIST_MARK ();
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (18, cons_mark, "cons-mark", 0, 0, 0)
+VM_DEFINE_INSTRUCTION (20, cons_mark, "cons-mark", 0, 0, 0)
 {
   POP_CONS_MARK ();
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (19, vector_mark, "vector-mark", 0, 0, 0)
+VM_DEFINE_INSTRUCTION (21, vector_mark, "vector-mark", 0, 0, 0)
 {
   POP_LIST_MARK ();
   SYNC_REGISTER ();
@@ -222,7 +222,7 @@ VM_DEFINE_INSTRUCTION (19, vector_mark, "vector-mark", 0, 
0, 0)
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (20, list_break, "list-break", 0, 0, 0)
+VM_DEFINE_INSTRUCTION (22, list_break, "list-break", 0, 0, 0)
 {
   SCM l;
   POP (l);
@@ -248,9 +248,11 @@ VM_DEFINE_INSTRUCTION (20, list_break, "list-break", 0, 0, 
0)
 #define VARIABLE_SET(v,o)      SCM_VARIABLE_SET (v, o)
 #define VARIABLE_BOUNDP(v)      (VARIABLE_REF (v) != SCM_UNDEFINED)
 
+#define FREE_VARIABLE_REF(i)   free_vars[i]
+
 /* ref */
 
-VM_DEFINE_INSTRUCTION (21, object_ref, "object-ref", 1, 0, 1)
+VM_DEFINE_INSTRUCTION (23, object_ref, "object-ref", 1, 0, 1)
 {
   register unsigned objnum = FETCH ();
   CHECK_OBJECT (objnum);
@@ -258,29 +260,25 @@ VM_DEFINE_INSTRUCTION (21, object_ref, "object-ref", 1, 
0, 1)
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (22, local_ref, "local-ref", 1, 0, 1)
+/* FIXME: necessary? elt 255 of the vector could be a vector... */
+VM_DEFINE_INSTRUCTION (24, long_object_ref, "long-object-ref", 2, 0, 1)
 {
-  PUSH (LOCAL_REF (FETCH ()));
-  ASSERT_BOUND (*sp);
+  unsigned int objnum = FETCH ();
+  objnum <<= 8;
+  objnum += FETCH ();
+  CHECK_OBJECT (objnum);
+  PUSH (OBJECT_REF (objnum));
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (23, external_ref, "external-ref", 1, 0, 1)
+VM_DEFINE_INSTRUCTION (25, local_ref, "local-ref", 1, 0, 1)
 {
-  unsigned int i;
-  SCM e = external;
-  for (i = FETCH (); i; i--)
-    {
-      CHECK_EXTERNAL(e);
-      e = SCM_CDR (e);
-    }
-  CHECK_EXTERNAL(e);
-  PUSH (SCM_CAR (e));
+  PUSH (LOCAL_REF (FETCH ()));
   ASSERT_BOUND (*sp);
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (24, variable_ref, "variable-ref", 0, 0, 1)
+VM_DEFINE_INSTRUCTION (27, variable_ref, "variable-ref", 0, 0, 1)
 {
   SCM x = *sp;
 
@@ -299,7 +297,7 @@ VM_DEFINE_INSTRUCTION (24, variable_ref, "variable-ref", 0, 
0, 1)
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (25, toplevel_ref, "toplevel-ref", 1, 0, 1)
+VM_DEFINE_INSTRUCTION (28, toplevel_ref, "toplevel-ref", 1, 0, 1)
 {
   unsigned objnum = FETCH ();
   SCM what;
@@ -322,38 +320,48 @@ VM_DEFINE_INSTRUCTION (25, toplevel_ref, "toplevel-ref", 
1, 0, 1)
   NEXT;
 }
 
-/* set */
-
-VM_DEFINE_INSTRUCTION (26, local_set, "local-set", 1, 1, 0)
+VM_DEFINE_INSTRUCTION (29, long_toplevel_ref, "long-toplevel-ref", 2, 0, 1)
 {
-  LOCAL_SET (FETCH (), *sp);
-  DROP ();
+  SCM what;
+  unsigned int objnum = FETCH ();
+  objnum <<= 8;
+  objnum += FETCH ();
+  CHECK_OBJECT (objnum);
+  what = OBJECT_REF (objnum);
+
+  if (!SCM_VARIABLEP (what)) 
+    {
+      SYNC_REGISTER ();
+      what = resolve_variable (what, scm_program_module (program));
+      if (!VARIABLE_BOUNDP (what))
+        {
+          finish_args = scm_list_1 (what);
+          goto vm_error_unbound;
+        }
+      OBJECT_SET (objnum, what);
+    }
+
+  PUSH (VARIABLE_REF (what));
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (27, external_set, "external-set", 1, 1, 0)
+/* set */
+
+VM_DEFINE_INSTRUCTION (30, local_set, "local-set", 1, 1, 0)
 {
-  unsigned int i;
-  SCM e = external;
-  for (i = FETCH (); i; i--)
-    {
-      CHECK_EXTERNAL(e);
-      e = SCM_CDR (e);
-    }
-  CHECK_EXTERNAL(e);
-  SCM_SETCAR (e, *sp);
+  LOCAL_SET (FETCH (), *sp);
   DROP ();
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (28, variable_set, "variable-set", 0, 1, 0)
+VM_DEFINE_INSTRUCTION (32, variable_set, "variable-set", 0, 1, 0)
 {
   VARIABLE_SET (sp[0], sp[-1]);
   DROPN (2);
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (29, toplevel_set, "toplevel-set", 1, 1, 0)
+VM_DEFINE_INSTRUCTION (33, toplevel_set, "toplevel-set", 1, 1, 0)
 {
   unsigned objnum = FETCH ();
   SCM what;
@@ -372,6 +380,27 @@ VM_DEFINE_INSTRUCTION (29, toplevel_set, "toplevel-set", 
1, 1, 0)
   NEXT;
 }
 
+VM_DEFINE_INSTRUCTION (34, long_toplevel_set, "long-toplevel-set", 2, 1, 0)
+{
+  SCM what;
+  unsigned int objnum = FETCH ();
+  objnum <<= 8;
+  objnum += FETCH ();
+  CHECK_OBJECT (objnum);
+  what = OBJECT_REF (objnum);
+
+  if (!SCM_VARIABLEP (what)) 
+    {
+      SYNC_BEFORE_GC ();
+      what = resolve_variable (what, scm_program_module (program));
+      OBJECT_SET (objnum, what);
+    }
+
+  VARIABLE_SET (what, *sp);
+  DROP ();
+  NEXT;
+}
+
 
 /*
  * branch and jump
@@ -396,7 +425,7 @@ VM_DEFINE_INSTRUCTION (29, toplevel_set, "toplevel-set", 1, 
1, 0)
   NEXT;                                                \
 }
 
-VM_DEFINE_INSTRUCTION (31, br, "br", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (35, br, "br", 2, 0, 0)
 {
   int h = FETCH ();
   int l = FETCH ();
@@ -404,34 +433,34 @@ VM_DEFINE_INSTRUCTION (31, br, "br", 2, 0, 0)
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (32, br_if, "br-if", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (36, br_if, "br-if", 2, 0, 0)
 {
   BR (!SCM_FALSEP (*sp));
 }
 
-VM_DEFINE_INSTRUCTION (33, br_if_not, "br-if-not", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (37, br_if_not, "br-if-not", 2, 0, 0)
 {
   BR (SCM_FALSEP (*sp));
 }
 
-VM_DEFINE_INSTRUCTION (34, br_if_eq, "br-if-eq", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (38, br_if_eq, "br-if-eq", 2, 0, 0)
 {
   sp--; /* underflow? */
   BR (SCM_EQ_P (sp[0], sp[1]));
 }
 
-VM_DEFINE_INSTRUCTION (35, br_if_not_eq, "br-if-not-eq", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (39, br_if_not_eq, "br-if-not-eq", 2, 0, 0)
 {
   sp--; /* underflow? */
   BR (!SCM_EQ_P (sp[0], sp[1]));
 }
 
-VM_DEFINE_INSTRUCTION (36, br_if_null, "br-if-null", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (40, br_if_null, "br-if-null", 2, 0, 0)
 {
   BR (SCM_NULLP (*sp));
 }
 
-VM_DEFINE_INSTRUCTION (37, br_if_not_null, "br-if-not-null", 2, 0, 0)
+VM_DEFINE_INSTRUCTION (41, br_if_not_null, "br-if-not-null", 2, 0, 0)
 {
   BR (!SCM_NULLP (*sp));
 }
@@ -441,15 +470,7 @@ VM_DEFINE_INSTRUCTION (37, br_if_not_null, 
"br-if-not-null", 2, 0, 0)
  * Subprogram call
  */
 
-VM_DEFINE_INSTRUCTION (38, make_closure, "make-closure", 0, 1, 1)
-{
-  SYNC_BEFORE_GC ();
-  SCM_NEWSMOB3 (*sp, scm_tc16_program, SCM_PROGRAM_OBJCODE (*sp),
-                SCM_PROGRAM_OBJTABLE (*sp), external);
-  NEXT;
-}
-
-VM_DEFINE_INSTRUCTION (39, call, "call", 1, -1, 1)
+VM_DEFINE_INSTRUCTION (43, call, "call", 1, -1, 1)
 {
   SCM x;
   nargs = FETCH ();
@@ -570,7 +591,7 @@ VM_DEFINE_INSTRUCTION (39, call, "call", 1, -1, 1)
   goto vm_error_wrong_type_apply;
 }
 
-VM_DEFINE_INSTRUCTION (40, goto_args, "goto/args", 1, -1, 1)
+VM_DEFINE_INSTRUCTION (44, goto_args, "goto/args", 1, -1, 1)
 {
   register SCM x;
   nargs = FETCH ();
@@ -597,12 +618,6 @@ VM_DEFINE_INSTRUCTION (40, goto_args, "goto/args", 1, -1, 
1)
       sp -= 2;
       NULLSTACK (bp->nargs + 1);
 
-      /* Freshen the externals */
-      external = SCM_PROGRAM_EXTERNALS (x);
-      for (i = 0; i < bp->nexts; i++)
-        CONS (external, SCM_UNDEFINED, external);
-      SCM_FRAME_DATA_ADDRESS (fp)[0] = external;
-
       /* Init locals to valid SCM values */
       for (i = 0; i < bp->nlocs; i++)
        LOCAL_SET (i + bp->nargs, SCM_UNDEFINED);
@@ -651,7 +666,7 @@ VM_DEFINE_INSTRUCTION (40, goto_args, "goto/args", 1, -1, 1)
          sure we have space for the locals now */
       data = SCM_FRAME_DATA_ADDRESS (fp);
       ip = bp->base;
-      stack_base = data + 3;
+      stack_base = data + 2;
       sp = stack_base;
       CHECK_OVERFLOW ();
 
@@ -666,17 +681,9 @@ VM_DEFINE_INSTRUCTION (40, goto_args, "goto/args", 1, -1, 
1)
         data[-i] = SCM_UNDEFINED;
       
       /* Set frame data */
-      data[3] = (SCM)ra;
-      data[2] = (SCM)mvra;
-      data[1] = (SCM)dl;
-
-      /* Postpone initializing external vars, because if the CONS causes a GC,
-         we want the stack marker to see the data array formatted as expected. 
*/
-      data[0] = SCM_UNDEFINED;
-      external = SCM_PROGRAM_EXTERNALS (fp[-1]);
-      for (i = 0; i < bp->nexts; i++)
-        CONS (external, SCM_UNDEFINED, external);
-      data[0] = external;
+      data[2] = (SCM)ra;
+      data[1] = (SCM)mvra;
+      data[0] = (SCM)dl;
 
       ENTER_HOOK ();
       APPLY_HOOK ();
@@ -764,7 +771,7 @@ VM_DEFINE_INSTRUCTION (40, goto_args, "goto/args", 1, -1, 1)
   goto vm_error_wrong_type_apply;
 }
 
-VM_DEFINE_INSTRUCTION (41, goto_nargs, "goto/nargs", 0, 0, 1)
+VM_DEFINE_INSTRUCTION (45, goto_nargs, "goto/nargs", 0, 0, 1)
 {
   SCM x;
   POP (x);
@@ -773,7 +780,7 @@ VM_DEFINE_INSTRUCTION (41, goto_nargs, "goto/nargs", 0, 0, 
1)
   goto vm_goto_args;
 }
 
-VM_DEFINE_INSTRUCTION (42, call_nargs, "call/nargs", 0, 0, 1)
+VM_DEFINE_INSTRUCTION (46, call_nargs, "call/nargs", 0, 0, 1)
 {
   SCM x;
   POP (x);
@@ -782,7 +789,7 @@ VM_DEFINE_INSTRUCTION (42, call_nargs, "call/nargs", 0, 0, 
1)
   goto vm_call;
 }
 
-VM_DEFINE_INSTRUCTION (43, mv_call, "mv-call", 3, -1, 1)
+VM_DEFINE_INSTRUCTION (47, mv_call, "mv-call", 3, -1, 1)
 {
   SCM x;
   signed short offset;
@@ -801,7 +808,7 @@ VM_DEFINE_INSTRUCTION (43, mv_call, "mv-call", 3, -1, 1)
       CACHE_PROGRAM ();
       INIT_ARGS ();
       NEW_FRAME ();
-      SCM_FRAME_DATA_ADDRESS (fp)[2] = (SCM)(SCM_FRAME_RETURN_ADDRESS (fp) + 
offset);
+      SCM_FRAME_DATA_ADDRESS (fp)[1] = (SCM)(SCM_FRAME_RETURN_ADDRESS (fp) + 
offset);
       ENTER_HOOK ();
       APPLY_HOOK ();
       NEXT;
@@ -843,7 +850,7 @@ VM_DEFINE_INSTRUCTION (43, mv_call, "mv-call", 3, -1, 1)
   goto vm_error_wrong_type_apply;
 }
 
-VM_DEFINE_INSTRUCTION (44, apply, "apply", 1, -1, 1)
+VM_DEFINE_INSTRUCTION (48, apply, "apply", 1, -1, 1)
 {
   int len;
   SCM ls;
@@ -862,7 +869,7 @@ VM_DEFINE_INSTRUCTION (44, apply, "apply", 1, -1, 1)
   goto vm_call;
 }
 
-VM_DEFINE_INSTRUCTION (45, goto_apply, "goto/apply", 1, -1, 1)
+VM_DEFINE_INSTRUCTION (49, goto_apply, "goto/apply", 1, -1, 1)
 {
   int len;
   SCM ls;
@@ -881,7 +888,7 @@ VM_DEFINE_INSTRUCTION (45, goto_apply, "goto/apply", 1, -1, 
1)
   goto vm_goto_args;
 }
 
-VM_DEFINE_INSTRUCTION (46, call_cc, "call/cc", 0, 1, 1)
+VM_DEFINE_INSTRUCTION (50, call_cc, "call/cc", 0, 1, 1)
 {
   int first;
   SCM proc, cont;
@@ -915,7 +922,7 @@ VM_DEFINE_INSTRUCTION (46, call_cc, "call/cc", 0, 1, 1)
     }
 }
 
-VM_DEFINE_INSTRUCTION (47, goto_cc, "goto/cc", 0, 1, 1)
+VM_DEFINE_INSTRUCTION (51, goto_cc, "goto/cc", 0, 1, 1)
 {
   int first;
   SCM proc, cont;
@@ -947,7 +954,7 @@ VM_DEFINE_INSTRUCTION (47, goto_cc, "goto/cc", 0, 1, 1)
     }
 }
 
-VM_DEFINE_INSTRUCTION (48, return, "return", 0, 1, 1)
+VM_DEFINE_INSTRUCTION (52, return, "return", 0, 1, 1)
 {
  vm_return:
   EXIT_HOOK ();
@@ -960,12 +967,12 @@ VM_DEFINE_INSTRUCTION (48, return, "return", 0, 1, 1)
 
     POP (ret);
     ASSERT (sp == stack_base);
-    ASSERT (stack_base == data + 3);
+    ASSERT (stack_base == data + 2);
 
     /* Restore registers */
     sp = SCM_FRAME_LOWER_ADDRESS (fp);
-    ip = SCM_FRAME_BYTE_CAST (data[3]);
-    fp = SCM_FRAME_STACK_CAST (data[1]);
+    ip = SCM_FRAME_BYTE_CAST (data[2]);
+    fp = SCM_FRAME_STACK_CAST (data[0]);
     {
 #ifdef VM_ENABLE_STACK_NULLING
       int nullcount = stack_base - sp;
@@ -981,12 +988,11 @@ VM_DEFINE_INSTRUCTION (48, return, "return", 0, 1, 1)
   /* Restore the last program */
   program = SCM_FRAME_PROGRAM (fp);
   CACHE_PROGRAM ();
-  CACHE_EXTERNAL ();
   CHECK_IP ();
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (49, return_values, "return/values", 1, -1, -1)
+VM_DEFINE_INSTRUCTION (53, return_values, "return/values", 1, -1, -1)
 {
   /* nvalues declared at top level, because for some reason gcc seems to think
      that perhaps it might be used without declaration. Fooey to that, I say. 
*/
@@ -998,16 +1004,16 @@ VM_DEFINE_INSTRUCTION (49, return_values, 
"return/values", 1, -1, -1)
   RETURN_HOOK ();
 
   data = SCM_FRAME_DATA_ADDRESS (fp);
-  ASSERT (stack_base == data + 3);
+  ASSERT (stack_base == data + 2);
 
-  /* data[2] is the mv return address */
-  if (nvalues != 1 && data[2]) 
+  /* data[1] is the mv return address */
+  if (nvalues != 1 && data[1]) 
     {
       int i;
       /* Restore registers */
       sp = SCM_FRAME_LOWER_ADDRESS (fp) - 1;
-      ip = SCM_FRAME_BYTE_CAST (data[2]); /* multiple value ra */
-      fp = SCM_FRAME_STACK_CAST (data[1]);
+      ip = SCM_FRAME_BYTE_CAST (data[1]); /* multiple value ra */
+      fp = SCM_FRAME_STACK_CAST (data[0]);
         
       /* Push return values, and the number of values */
       for (i = 0; i < nvalues; i++)
@@ -1026,8 +1032,8 @@ VM_DEFINE_INSTRUCTION (49, return_values, 
"return/values", 1, -1, -1)
          continuation.) */
       /* Restore registers */
       sp = SCM_FRAME_LOWER_ADDRESS (fp) - 1;
-      ip = SCM_FRAME_BYTE_CAST (data[3]); /* single value ra */
-      fp = SCM_FRAME_STACK_CAST (data[1]);
+      ip = SCM_FRAME_BYTE_CAST (data[2]); /* single value ra */
+      fp = SCM_FRAME_STACK_CAST (data[0]);
         
       /* Push first value */
       *++sp = stack_base[1];
@@ -1042,12 +1048,11 @@ VM_DEFINE_INSTRUCTION (49, return_values, 
"return/values", 1, -1, -1)
   /* Restore the last program */
   program = SCM_FRAME_PROGRAM (fp);
   CACHE_PROGRAM ();
-  CACHE_EXTERNAL ();
   CHECK_IP ();
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (50, return_values_star, "return/values*", 1, -1, -1)
+VM_DEFINE_INSTRUCTION (54, return_values_star, "return/values*", 1, -1, -1)
 {
   SCM l;
 
@@ -1070,7 +1075,7 @@ VM_DEFINE_INSTRUCTION (50, return_values_star, 
"return/values*", 1, -1, -1)
   goto vm_return_values;
 }
 
-VM_DEFINE_INSTRUCTION (51, truncate_values, "truncate-values", 2, -1, -1)
+VM_DEFINE_INSTRUCTION (55, truncate_values, "truncate-values", 2, -1, -1)
 {
   SCM x;
   int nbinds, rest;
@@ -1093,62 +1098,92 @@ VM_DEFINE_INSTRUCTION (51, truncate_values, 
"truncate-values", 2, -1, -1)
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (52, long_object_ref, "long-object-ref", 2, 0, 1)
+VM_DEFINE_INSTRUCTION (56, box, "box", 1, 1, 0)
 {
-  unsigned int objnum = FETCH ();
-  objnum <<= 8;
-  objnum += FETCH ();
-  CHECK_OBJECT (objnum);
-  PUSH (OBJECT_REF (objnum));
+  SCM val;
+  POP (val);
+  SYNC_BEFORE_GC ();
+  LOCAL_SET (FETCH (), scm_cell (scm_tc7_variable, SCM_UNPACK (val)));
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (53, long_toplevel_ref, "long-toplevel-ref", 2, 0, 1)
+/* for letrec:
+   (let ((a *undef*) (b *undef*) ...)
+     (set! a (lambda () (b ...)))
+     ...)
+ */
+VM_DEFINE_INSTRUCTION (57, empty_box, "empty-box", 1, 0, 0)
 {
-  SCM what;
-  unsigned int objnum = FETCH ();
-  objnum <<= 8;
-  objnum += FETCH ();
-  CHECK_OBJECT (objnum);
-  what = OBJECT_REF (objnum);
+  SYNC_BEFORE_GC ();
+  LOCAL_SET (FETCH (),
+             scm_cell (scm_tc7_variable, SCM_UNPACK (SCM_UNDEFINED)));
+  NEXT;
+}
 
-  if (!SCM_VARIABLEP (what)) 
-    {
-      SYNC_REGISTER ();
-      what = resolve_variable (what, scm_program_module (program));
-      if (!VARIABLE_BOUNDP (what))
-        {
-          finish_args = scm_list_1 (what);
-          goto vm_error_unbound;
-        }
-      OBJECT_SET (objnum, what);
-    }
+VM_DEFINE_INSTRUCTION (58, local_boxed_ref, "local-boxed-ref", 1, 0, 1)
+{
+  SCM v = LOCAL_REF (FETCH ());
+  ASSERT_BOUND_VARIABLE (v);
+  PUSH (VARIABLE_REF (v));
+  NEXT;
+}
 
-  PUSH (VARIABLE_REF (what));
+VM_DEFINE_INSTRUCTION (59, local_boxed_set, "local-boxed-set", 1, 1, 0)
+{
+  SCM v, val;
+  v = LOCAL_REF (FETCH ());
+  POP (val);
+  ASSERT_VARIABLE (v);
+  VARIABLE_SET (v, val);
   NEXT;
 }
 
-VM_DEFINE_INSTRUCTION (54, long_toplevel_set, "long-toplevel-set", 2, 1, 0)
+VM_DEFINE_INSTRUCTION (60, free_ref, "free-ref", 1, 0, 1)
 {
-  SCM what;
-  unsigned int objnum = FETCH ();
-  objnum <<= 8;
-  objnum += FETCH ();
-  CHECK_OBJECT (objnum);
-  what = OBJECT_REF (objnum);
+  scm_t_uint8 idx = FETCH ();
+  
+  CHECK_FREE_VARIABLE (idx);
+  PUSH (FREE_VARIABLE_REF (idx));
+  NEXT;
+}
 
-  if (!SCM_VARIABLEP (what)) 
-    {
-      SYNC_BEFORE_GC ();
-      what = resolve_variable (what, scm_program_module (program));
-      OBJECT_SET (objnum, what);
-    }
+/* no free-set -- if a var is assigned, it should be in a box */
 
-  VARIABLE_SET (what, *sp);
-  DROP ();
+VM_DEFINE_INSTRUCTION (61, free_boxed_ref, "free-boxed-ref", 1, 0, 1)
+{
+  SCM v;
+  scm_t_uint8 idx = FETCH ();
+  CHECK_FREE_VARIABLE (idx);
+  v = FREE_VARIABLE_REF (idx);
+  ASSERT_BOUND_VARIABLE (v);
+  PUSH (VARIABLE_REF (v));
+  NEXT;
+}
+
+VM_DEFINE_INSTRUCTION (62, free_boxed_set, "free-boxed-set", 1, 1, 0)
+{
+  SCM v, val;
+  scm_t_uint8 idx = FETCH ();
+  POP (val);
+  CHECK_FREE_VARIABLE (idx);
+  v = FREE_VARIABLE_REF (idx);
+  ASSERT_BOUND_VARIABLE (v);
+  VARIABLE_SET (v, val);
   NEXT;
 }
 
+VM_DEFINE_INSTRUCTION (63, make_closure, "make-closure", 0, 2, 1)
+{
+  SCM vect;
+  POP (vect);
+  SYNC_BEFORE_GC ();
+  /* fixme underflow */
+  SCM_NEWSMOB3 (*sp, scm_tc16_program, SCM_PROGRAM_OBJCODE (*sp),
+                SCM_PROGRAM_OBJTABLE (*sp), vect);
+  NEXT;
+}
+
+
 /*
 (defun renumber-ops ()
   "start from top of buffer and renumber 'VM_DEFINE_FOO (\n' sequences"
diff --git a/libguile/vm.c b/libguile/vm.c
index f753ea2..957baf6 100644
--- a/libguile/vm.c
+++ b/libguile/vm.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2001 Free Software Foundation, Inc.
+/* Copyright (C) 2001, 2009 Free Software Foundation, Inc.
  * 
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -259,7 +259,7 @@ really_make_boot_program (long nargs)
 
   u8vec = make_u8vector (bytes.bytes, sizeof (bytes.bytes));
   ret = scm_make_program (scm_bytecode_to_objcode (u8vec),
-                          SCM_BOOL_F, SCM_EOL);
+                          SCM_BOOL_F, SCM_BOOL_F);
   SCM_SET_SMOB_FLAGS (ret, SCM_F_PROGRAM_IS_BOOT);
 
   return ret;
@@ -663,7 +663,7 @@ SCM_DEFINE (scm_vm_trace_frame, "vm-trace-frame", 1, 0, 0,
 SCM scm_load_compiled_with_vm (SCM file)
 {
   SCM program = scm_make_program (scm_load_objcode (file),
-                                  SCM_BOOL_F, SCM_EOL);
+                                  SCM_BOOL_F, SCM_BOOL_F);
   
   return scm_c_vm_run (scm_the_vm (), program, NULL, 0);
 }
diff --git a/module/language/assembly.scm b/module/language/assembly.scm
index 3a0b387..0ad94be 100644
--- a/module/language/assembly.scm
+++ b/module/language/assembly.scm
@@ -28,7 +28,7 @@
             assembly-pack assembly-unpack
             object->assembly assembly->object))
 
-;; nargs, nrest, nlocs, nexts, len, metalen
+;; nargs, nrest, nlocs, <unused>, len, metalen
 (define *program-header-len* (+ 1 1 1 1 4 4))
 
 ;; lengths are encoded in 3 bytes
@@ -54,7 +54,7 @@
      (+ 1 *len-len* (bytevector-length bv)))
     ((define ,str)
      (+ 1 *len-len* (string-length str)))
-    ((load-program ,nargs ,nrest ,nlocs ,nexts ,labels ,len ,meta . ,code)
+    ((load-program ,nargs ,nrest ,nlocs ,labels ,len ,meta . ,code)
      (+ 1 *program-header-len* len (if meta (1- (byte-length meta)) 0)))
     ((,inst . _) (guard (>= (instruction-length inst) 0))
      (+ 1 (instruction-length inst)))
diff --git a/module/language/assembly/compile-bytecode.scm 
b/module/language/assembly/compile-bytecode.scm
index 4b9f7b7..0a14898 100644
--- a/module/language/assembly/compile-bytecode.scm
+++ b/module/language/assembly/compile-bytecode.scm
@@ -89,12 +89,11 @@
           (len (instruction-length inst)))
       (write-byte opcode)
       (pmatch asm
-        ((load-program ,nargs ,nrest ,nlocs ,nexts
-                       ,labels ,length ,meta . ,code)
+        ((load-program ,nargs ,nrest ,nlocs ,labels ,length ,meta . ,code)
          (write-byte nargs)
          (write-byte nrest)
          (write-byte nlocs)
-         (write-byte nexts)
+         (write-byte 0) ;; what used to be nexts
          (write-uint32 length)
          (write-uint32 (if meta (1- (byte-length meta)) 0))
          (letrec ((i 0)
diff --git a/module/language/assembly/decompile-bytecode.scm 
b/module/language/assembly/decompile-bytecode.scm
index fdf27ec..56f58f7 100644
--- a/module/language/assembly/decompile-bytecode.scm
+++ b/module/language/assembly/decompile-bytecode.scm
@@ -1,6 +1,6 @@
 ;;; Guile VM code converters
 
-;; Copyright (C) 2001 Free Software Foundation, Inc.
+;; Copyright (C) 2001, 2009 Free Software Foundation, Inc.
 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -49,7 +49,7 @@
         (- x (ash 1 16)))))
 
 (define (decode-load-program pop)
-  (let* ((nargs (pop)) (nrest (pop)) (nlocs (pop)) (nexts (pop))
+  (let* ((nargs (pop)) (nrest (pop)) (nlocs (pop)) (unused (pop))
          (a (pop)) (b (pop)) (c (pop)) (d (pop))
          (e (pop)) (f (pop)) (g (pop)) (h (pop))
          (len (+ a (ash b 8) (ash c 16) (ash d 24)))
@@ -74,7 +74,7 @@
       (cond ((> i len)
              (error "error decoding program -- read too many bytes" out))
             ((= i len)
-             `(load-program ,nargs ,nrest ,nlocs ,nexts
+             `(load-program ,nargs ,nrest ,nlocs 
                             ,(map (lambda (x) (cons (cdr x) (car x)))
                                   (reverse labels))
                             ,len
diff --git a/module/language/assembly/disassemble.scm 
b/module/language/assembly/disassemble.scm
index 0a35050..d41c816 100644
--- a/module/language/assembly/disassemble.scm
+++ b/module/language/assembly/disassemble.scm
@@ -1,6 +1,6 @@
 ;;; Guile VM code converters
 
-;; Copyright (C) 2001 Free Software Foundation, Inc.
+;; Copyright (C) 2001, 2009 Free Software Foundation, Inc.
 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -35,12 +35,11 @@
 
 (define (disassemble-load-program asm env)
   (pmatch asm
-    ((load-program ,nargs ,nrest ,nlocs ,nexts ,labels ,len ,meta . ,code)
+    ((load-program ,nargs ,nrest ,nlocs ,labels ,len ,meta . ,code)
      (let ((objs  (and env (assq-ref env 'objects)))
+           (free-vars (and env (assq-ref env 'free-vars)))
            (meta  (and env (assq-ref env 'meta)))
-           (exts  (and env (assq-ref env 'exts)))
            (blocs (and env (assq-ref env 'blocs)))
-           (bexts (and env (assq-ref env 'bexts)))
            (srcs  (and env (assq-ref env 'sources))))
        (let lp ((pos 0) (code code) (programs '()))
          (cond
@@ -63,13 +62,13 @@
                       (acons sym asm programs))))
                (else
                 (print-info pos asm
-                            (code-annotation end asm objs nargs blocs bexts
+                            (code-annotation end asm objs nargs blocs
                                              labels)
                             (and=> (and srcs (assq end srcs)) source->string))
                 (lp (+ pos (byte-length asm)) (cdr code) programs)))))))
                  
-       (if (pair? exts)
-           (disassemble-externals exts))
+       (if (pair? free-vars)
+           (disassemble-free-vars free-vars))
        (if meta
            (disassemble-meta meta))
 
@@ -92,13 +91,12 @@
        ((= n len) (newline))
       (print-info n (vector-ref objs n) #f #f))))
 
-(define (disassemble-externals exts)
-  (display "Externals:\n\n")
-  (let ((len (length exts)))
-    (do ((n 0 (1+ n))
-        (l exts (cdr l)))
-       ((null? l) (newline))
-      (print-info n (car l) #f #f))))
+(define (disassemble-free-vars free-vars)
+  (display "Free variables:\n\n")
+  (let ((i 0))
+    (cond ((< i (vector-length free-vars))
+           (print-info i (vector-ref free-vars i) #f #f)
+           (lp (1+ i))))))
 
 (define-macro (unless test . body)
   `(if (not ,test) (begin ,@body)))
@@ -122,7 +120,7 @@
 (define (make-int16 byte1 byte2)
   (+ (* byte1 256) byte2))
 
-(define (code-annotation end-addr code objs nargs blocs bexts labels)
+(define (code-annotation end-addr code objs nargs blocs labels)
   (let* ((code (assembly-unpack code))
          (inst (car code))
          (args (cdr code)))
@@ -133,7 +131,7 @@
        (list "-> ~A" (assq-ref labels (car args))))
       ((object-ref)
        (and objs (list "~s" (vector-ref objs (car args)))))
-      ((local-ref local-set)
+      ((local-ref local-boxed-ref local-set local-boxed-set)
        (and blocs
             (let lp ((bindings (list-ref blocs (car args))))
               (and (pair? bindings)
@@ -143,13 +141,9 @@
                          (list "`~a'address@hidden (arg)~]"
                                (binding:name b) (< (binding:index b) nargs))
                          (lp (cdr bindings))))))))
-      ((external-ref external-set)
-       (and bexts
-            (if (< (car args) (length bexts))
-                (let ((b (list-ref bexts (car args))))
-                  (list "`~a'address@hidden (arg)~]"
-                        (binding:name b) (< (binding:index b) nargs)))
-                (list "(closure variable)"))))
+      ((free-ref free-boxed-ref free-boxed-set)
+       ;; FIXME: we can do better than this
+       (list "(closure variable)"))
       ((toplevel-ref toplevel-set)
        (and objs
             (let ((v (vector-ref objs (car args))))
diff --git a/module/language/glil.scm b/module/language/glil.scm
index 38b915f..0777073 100644
--- a/module/language/glil.scm
+++ b/module/language/glil.scm
@@ -1,6 +1,6 @@
 ;;; Guile Low Intermediate Language
 
-;; Copyright (C) 2001 Free Software Foundation, Inc.
+;; Copyright (C) 2001, 2009 Free Software Foundation, Inc.
 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -24,9 +24,9 @@
   #:use-module ((srfi srfi-1) #:select (fold))
   #:export
   (<glil-program> make-glil-program glil-program?
-   glil-program-nargs glil-program-nrest glil-program-nlocs glil-program-nexts
-   glil-program-meta glil-program-body glil-program-closure-level
-
+   glil-program-nargs glil-program-nrest glil-program-nlocs
+   glil-program-meta glil-program-body
+   
    <glil-bind> make-glil-bind glil-bind?
    glil-bind-vars
 
@@ -43,11 +43,8 @@
    <glil-const> make-glil-const glil-const?
    glil-const-obj
 
-   <glil-local> make-glil-local glil-local?
-   glil-local-op glil-local-index
-
-   <glil-external> make-glil-external glil-external?
-   glil-external-op glil-external-depth glil-external-index
+   <glil-lexical> make-glil-lexical glil-lexical?
+   glil-lexical-local? glil-lexical-boxed? glil-lexical-op glil-lexical-index
 
    <glil-toplevel> make-glil-toplevel glil-toplevel?
    glil-toplevel-op glil-toplevel-name
@@ -74,7 +71,7 @@
 
 (define-type (<glil> #:printer print-glil)
   ;; Meta operations
-  (<glil-program> nargs nrest nlocs nexts meta body (closure-level #f))
+  (<glil-program> nargs nrest nlocs meta body)
   (<glil-bind> vars)
   (<glil-mv-bind> vars rest)
   (<glil-unbind>)
@@ -83,8 +80,7 @@
   (<glil-void>)
   (<glil-const> obj)
   ;; Variables
-  (<glil-local> op index)
-  (<glil-external> op depth index)
+  (<glil-lexical> local? boxed? op index)
   (<glil-toplevel> op name)
   (<glil-module> op mod name public?)
   ;; Controls
@@ -93,35 +89,19 @@
   (<glil-call> inst nargs)
   (<glil-mv-call> nargs ra))
 
-(define (compute-closure-level body)
-  (fold (lambda (x ret)
-          (record-case x
-            ((<glil-program> closure-level) (max ret closure-level))
-            ((<glil-external> depth) (max ret depth))
-            (else ret)))
-        0 body))
-
-(define %make-glil-program make-glil-program)
-(define (make-glil-program . args)
-  (let ((prog (apply %make-glil-program args)))
-    (if (not (glil-program-closure-level prog))
-        (set! (glil-program-closure-level prog)
-              (compute-closure-level (glil-program-body prog))))
-    prog))
-
 
+
 (define (parse-glil x)
   (pmatch x
-    ((program ,nargs ,nrest ,nlocs ,nexts ,meta . ,body)
-     (make-glil-program nargs nrest nlocs nexts meta (map parse-glil body)))
+    ((program ,nargs ,nrest ,nlocs ,meta . ,body)
+     (make-glil-program nargs nrest nlocs meta (map parse-glil body)))
     ((bind . ,vars) (make-glil-bind vars))
     ((mv-bind ,vars ,rest) (make-glil-mv-bind vars rest))
     ((unbind) (make-glil-unbind))
     ((source ,props) (make-glil-source props))
     ((void) (make-glil-void))
     ((const ,obj) (make-glil-const obj))
-    ((local ,op ,index) (make-glil-local op index))
-    ((external ,op ,depth ,index) (make-glil-external op depth index))
+    ((lexical ,local? ,boxed? ,op ,index) (make-glil-lexical local? boxed? op 
index))
     ((toplevel ,op ,name) (make-glil-toplevel op name))
     ((module public ,op ,mod ,name) (make-glil-module op mod name #t))
     ((module private ,op ,mod ,name) (make-glil-module op mod name #f))
@@ -134,8 +114,8 @@
 (define (unparse-glil glil)
   (record-case glil
     ;; meta
-    ((<glil-program> nargs nrest nlocs nexts meta body)
-     `(program ,nargs ,nrest ,nlocs ,nexts ,meta ,@(map unparse-glil body)))
+    ((<glil-program> nargs nrest nlocs meta body)
+     `(program ,nargs ,nrest ,nlocs ,meta ,@(map unparse-glil body)))
     ((<glil-bind> vars) `(bind ,@vars))
     ((<glil-mv-bind> vars rest) `(mv-bind ,vars ,rest))
     ((<glil-unbind>) `(unbind))
@@ -144,10 +124,8 @@
     ((<glil-void>) `(void))
     ((<glil-const> obj) `(const ,obj))
     ;; variables
-    ((<glil-local> op index)
-     `(local ,op ,index))
-    ((<glil-external> op depth index)
-     `(external ,op ,depth ,index))
+    ((<glil-lexical> local? boxed? op index)
+     `(lexical ,local? ,boxed? ,op ,index))
     ((<glil-toplevel> op name)
      `(toplevel ,op ,name))
     ((<glil-module> op mod name public?)
diff --git a/module/language/glil/compile-assembly.scm 
b/module/language/glil/compile-assembly.scm
index 0b92a4e..c7e26a8 100644
--- a/module/language/glil/compile-assembly.scm
+++ b/module/language/glil/compile-assembly.scm
@@ -72,14 +72,14 @@
   (if (and (null? bindings) (null? sources) (null? tail))
       #f
       (compile-assembly
-       (make-glil-program 0 0 0 0 '()
+       (make-glil-program 0 0 0 '()
                           (list
                            (make-glil-const `(,bindings ,sources ,@tail))
                            (make-glil-call 'return 1))))))
 
 ;; A functional stack of names of live variables.
-(define (make-open-binding name ext? index)
-  (list name ext? index))
+(define (make-open-binding name boxed? index)
+  (list name boxed? index))
 (define (make-closed-binding open-binding start end)
   (make-binding (car open-binding) (cadr open-binding)
                 (caddr open-binding) start end))
@@ -89,8 +89,8 @@
           (map
            (lambda (v)
              (pmatch v
-               ((,name local ,i) (make-open-binding name #f i))
-               ((,name external ,i) (make-open-binding name #t i))
+               ((,name ,boxed? ,i)
+                (make-open-binding name boxed? i))
                (else (error "unknown binding type" v))))
            vars)
           (car bindings))
@@ -128,13 +128,13 @@
 
 (define (compile-assembly glil)
   (receive (code . _)
-      (glil->assembly glil '() '(()) '() '() #f -1)
+      (glil->assembly glil #t '(()) '() '() #f -1)
     (car code)))
 (define (make-object-table objects)
   (and (not (null? objects))
        (list->vector (cons #f objects))))
 
-(define (glil->assembly glil nexts-stack bindings
+(define (glil->assembly glil toplevel? bindings
                         source-alist label-alist object-alist addr)
   (define (emit-code x)
     (values (map assembly-pack x) bindings source-alist label-alist 
object-alist))
@@ -142,60 +142,56 @@
     (values (map assembly-pack x) bindings source-alist label-alist 
object-alist))
 
   (record-case glil
-    ((<glil-program> nargs nrest nlocs nexts meta body closure-level)
-     (let ((toplevel? (null? nexts-stack)))
-       (define (process-body)
-         (let ((nexts-stack (cons nexts nexts-stack)))
-           (let lp ((body body) (code '()) (bindings '(())) (source-alist '())
-                    (label-alist '()) (object-alist (if toplevel? #f '())) 
(addr 0))
+    ((<glil-program> nargs nrest nlocs meta body)
+     (define (process-body)
+       (let lp ((body body) (code '()) (bindings '(())) (source-alist '())
+                (label-alist '()) (object-alist (if toplevel? #f '())) (addr 
0))
+         (cond
+          ((null? body)
+           (values (reverse code)
+                   (close-all-bindings bindings addr)
+                   (limn-sources (reverse! source-alist))
+                   (reverse label-alist)
+                   (and object-alist (map car (reverse object-alist)))
+                   addr))
+          (else
+           (receive (subcode bindings source-alist label-alist object-alist)
+               (glil->assembly (car body) #f bindings
+                               source-alist label-alist object-alist addr)
+             (lp (cdr body) (append (reverse subcode) code)
+                 bindings source-alist label-alist object-alist
+                 (addr+ addr subcode)))))))
+
+     (receive (code bindings sources labels objects len)
+         (process-body)
+       (let ((prog `(load-program ,nargs ,nrest ,nlocs ,labels
+                                  ,len
+                                  ,(make-meta bindings sources meta)
+                                  . ,code)))
+         (cond
+          (toplevel?
+           ;; toplevel bytecode isn't loaded by the vm, no way to do
+           ;; object table or closure capture (not in the bytecode,
+           ;; anyway)
+           (emit-code (align-program prog addr)))
+          (else
+           (let ((table (dump-object (make-object-table objects) addr)))
              (cond
-              ((null? body)
-               (values (reverse code)
-                       (close-all-bindings bindings addr)
-                       (limn-sources (reverse! source-alist))
-                       (reverse label-alist)
-                       (and object-alist (map car (reverse object-alist)))
-                       addr))
+              (object-alist
+               ;; if we are being compiled from something with an object
+               ;; table, cache the program there
+               (receive (i object-alist)
+                   (object-index-and-alist (make-subprogram table prog)
+                                           object-alist)
+                 (emit-code/object `(,(if (< i 256)
+                                          `(object-ref ,i)
+                                          `(long-object-ref ,(quotient i 256)
+                                                            ,(modulo i 256))))
+                                   object-alist)))
               (else
-               (receive (subcode bindings source-alist label-alist 
object-alist)
-                   (glil->assembly (car body) nexts-stack bindings
-                                   source-alist label-alist object-alist addr)
-                 (lp (cdr body) (append (reverse subcode) code)
-                     bindings source-alist label-alist object-alist
-                     (addr+ addr subcode))))))))
-
-       (receive (code bindings sources labels objects len)
-           (process-body)
-         (let ((prog `(load-program ,nargs ,nrest ,nlocs ,nexts ,labels
-                                    ,len
-                                    ,(make-meta bindings sources meta)
-                                    . ,code)))
-           (cond
-            (toplevel?
-             ;; toplevel bytecode isn't loaded by the vm, no way to do
-             ;; object table or closure capture (not in the bytecode,
-             ;; anyway)
-             (emit-code (align-program prog addr)))
-            (else
-             (let ((table (dump-object (make-object-table objects) addr))
-                   (closure (if (> closure-level 0) '((make-closure)) '())))
-               (cond
-                (object-alist
-                 ;; if we are being compiled from something with an object
-                 ;; table, cache the program there
-                 (receive (i object-alist)
-                     (object-index-and-alist (make-subprogram table prog)
-                                             object-alist)
-                   (emit-code/object `(,(if (< i 256)
-                                            `(object-ref ,i)
-                                            `(long-object-ref ,(quotient i 256)
-                                                              ,(modulo i 256)))
-                                       ,@closure)
-                                     object-alist)))
-                (else
-                 ;; otherwise emit a load directly
-                 (emit-code `(,@table ,@(align-program prog (addr+ addr table))
-                                      ,@closure)))))))))))
+               ;; otherwise emit a load directly
+               (emit-code `(,@table ,@(align-program prog (addr+ addr 
table))))))))))))
+    
     
     ((<glil-bind> vars)
      (values '()
@@ -244,19 +240,21 @@
                                                   ,(modulo i 256))))
                            object-alist)))))
 
-    ((<glil-local> op index)
-     (emit-code (if (eq? op 'ref)
-                    `((local-ref ,index))
-                    `((local-set ,index)))))
-
-    ((<glil-external> op depth index)
-     (emit-code (let lp ((d depth) (n 0) (stack nexts-stack))
-                  (if (> d 0)
-                      (lp (1- d) (+ n (car stack)) (cdr stack))
-                      (if (eq? op 'ref)
-                          `((external-ref ,(+ n index)))
-                          `((external-set ,(+ n index))))))))
-
+    ((<glil-lexical> local? boxed? op index)
+     (emit-code
+      `((,(if local?
+              (case op
+                ((ref) (if boxed? 'local-boxed-ref 'local-ref))
+                ((set) (if boxed? 'local-boxed-set 'local-set))
+                ((box) 'box)
+                ((empty-box) 'empty-box)
+                (else (error "what" op)))
+              (case op
+                ((ref) (if boxed? 'free-boxed-ref 'free-ref))
+                ((set) (if boxed? 'free-boxed-set (error "what." glil)))
+                (else (error "what" op))))
+         ,index))))
+    
     ((<glil-toplevel> op name)
      (case op
        ((ref set)
diff --git a/module/language/glil/decompile-assembly.scm 
b/module/language/glil/decompile-assembly.scm
index 502ef80..3cb887d 100644
--- a/module/language/glil/decompile-assembly.scm
+++ b/module/language/glil/decompile-assembly.scm
@@ -1,6 +1,6 @@
 ;;; Guile VM code converters
 
-;; Copyright (C) 2001 Free Software Foundation, Inc.
+;; Copyright (C) 2001, 2009 Free Software Foundation, Inc.
 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -31,8 +31,8 @@
 
 (define (decompile-toplevel x)
   (pmatch x
-    ((load-program ,nargs ,nrest ,nlocs ,nexts ,labels ,len ,meta . ,body)
-     (decompile-load-program nargs nrest nlocs nexts
+    ((load-program ,nargs ,nrest ,nlocs ,labels ,len ,meta . ,body)
+     (decompile-load-program nargs nrest nlocs
                              (decompile-meta meta)
                              body labels #f))
     (else
@@ -56,7 +56,7 @@
           ((glil-program? (car in)) (lp (cdr in) (cons (car in) out)))
           (else (lp (cdr in) (cons (make-glil-const (car l)) out))))))
 
-(define (decompile-load-program nargs nrest nlocs nexts meta body labels
+(define (decompile-load-program nargs nrest nlocs meta body labels
                                 objects)
   (let ((glil-labels (sort (map (lambda (x)
                                   (cons (cdr x) (make-glil-label (car x))))
@@ -100,19 +100,11 @@
       (cond
        ((null? in)
         (or (null? stack) (error "leftover stack insts" stack body))
-        (make-glil-program nargs nrest nlocs nexts props (reverse out) #f))
+        (make-glil-program nargs nrest nlocs props (reverse out) #f))
        ((pop-bindings! pos)
         => (lambda (bindings)
              (lp in stack
-                 (cons (make-glil-bind
-                        (map (lambda (x)
-                               (let ((name (binding:name x))
-                                     (i (binding:index x)))
-                                 (cond
-                                  ((binding:extp x) `(,name external ,i))
-                                  ((< i nargs) `(,name argument ,i))
-                                  (else `(,name local ,(- i nargs))))))
-                             bindings))
+                 (cons (make-glil-bind bindings)
                        out)
                  pos)))
        ((pop-unbindings! pos)
diff --git a/module/language/objcode/spec.scm b/module/language/objcode/spec.scm
index 76c1cbc..4cb600f 100644
--- a/module/language/objcode/spec.scm
+++ b/module/language/objcode/spec.scm
@@ -1,6 +1,6 @@
 ;;; Guile Lowlevel Intermediate Language
 
-;; Copyright (C) 2001 Free Software Foundation, Inc.
+;; Copyright (C) 2001, 2009 Free Software Foundation, Inc.
 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -31,7 +31,7 @@
   (if env (car env) (current-module)))
 
 (define (objcode-env-externals env)
-  (if env (cdr env) '()))
+  (and env (vector? (cdr env)) (cdr env)))
 
 (define (objcode->value x e opts)
   (let ((thunk (make-program x #f (objcode-env-externals e))))
@@ -66,23 +66,16 @@
    ((program? x)
     (let ((objs  (program-objects x))
           (meta  (program-meta x))
-          (exts  (program-external x))
+          (free-vars  (program-free-variables x))
           (binds (program-bindings x))
           (srcs  (program-sources x))
           (nargs (arity:nargs (program-arity x))))
-      (let ((blocs (and binds
-                        (collapse-locals
-                         (append (list-head binds nargs)
-                                 (filter (lambda (x) (not (binding:extp x)))
-                                         (list-tail binds nargs))))))
-            (bexts (and binds
-                        (filter binding:extp binds))))
+      (let ((blocs (and binds (collapse-locals binds))))
         (values (program-objcode x)
                 `((objects . ,objs)
                   (meta    . ,(and meta (meta)))
-                  (exts    . ,exts)
+                  (free-vars . ,free-vars)
                   (blocs   . ,blocs)
-                  (bexts   . ,bexts)
                   (sources . ,srcs))))))
    ((objcode? x)
     (values x #f))
diff --git a/module/language/tree-il/analyze.scm 
b/module/language/tree-il/analyze.scm
index 9768077..4ed796c 100644
--- a/module/language/tree-il/analyze.scm
+++ b/module/language/tree-il/analyze.scm
@@ -19,14 +19,37 @@
 ;;; Code:
 
 (define-module (language tree-il analyze)
+  #:use-module (srfi srfi-1)
   #:use-module (system base syntax)
   #:use-module (language tree-il)
   #:export (analyze-lexicals))
 
-;; allocation: the process of assigning a type and index to each var
-;; a var is external if it is heaps; assigning index is easy
-;; args are assigned in order
-;; locals are indexed as their linear position in the binding path
+;; Allocation is the process of assigning storage locations for lexical
+;; variables. A lexical variable has a distinct "address", or storage
+;; location, for each procedure in which it is referenced.
+;;
+;; A variable is "local", i.e., allocated on the stack, if it is
+;; referenced from within the procedure that defined it. Otherwise it is
+;; a "closure" variable. For example:
+;;
+;;    (lambda (a) a) ; a will be local
+;; `a' is local to the procedure.
+;;
+;;    (lambda (a) (lambda () a))
+;; `a' is local to the outer procedure, but a closure variable with
+;; respect to the inner procedure.
+;;
+;; If a variable is ever assigned, it needs to be heap-allocated
+;; ("boxed"). This is so that closures and continuations capture the
+;; variable's identity, not just one of the values it may have over the
+;; course of program execution. If the variable is never assigned, there
+;; is no distinction between value and identity, so closing over its
+;; identity (whether through closures or continuations) can make a copy
+;; of its value instead.
+;;
+;; Local variables are stored on the stack within a procedure's call
+;; frame. Their index into the stack is determined from their linear
+;; postion within a procedure's binding path:
 ;; (let (0 1)
 ;;   (let (2 3) ...)
 ;;   (let (2) ...))
@@ -48,49 +71,67 @@
 ;; case. A proper solution would be some sort of liveness analysis, and
 ;; not our linear allocation algorithm.
 ;;
-;; allocation:
-;;  sym -> (local . index) | (heap level . index)
-;;  lambda -> (nlocs . nexts)
+;; Closure variables are captured when a closure is created, and stored
+;; in a vector. Each closure variable has a unique index into that
+;; vector.
+;;
+;;
+;; The return value of `analyze-lexicals' is a hash table, the
+;; "allocation".
+;;
+;; The allocation maps gensyms -- recall that each lexically bound
+;; variable has a unique gensym -- to storage locations ("addresses").
+;; Since one gensym may have many storage locations, if it is referenced
+;; in many procedures, it is a two-level map.
+;;
+;; The allocation also stored information on how many local variables
+;; need to be allocated for each procedure, and information on what free
+;; variables to capture from its lexical parent procedure.
+;;
+;; That is:
+;;
+;;  sym -> {lambda -> address}
+;;  lambda -> (nlocs . free-locs)
+;;
+;; address := (local? boxed? . index)
+;; free-locs ::= ((sym0 . address0) (sym1 . address1) ...)
+;; free variable addresses are relative to parent proc.
+
+(define (make-hashq k v)
+  (let ((res (make-hash-table)))
+    (hashq-set! res k v)
+    res))
 
 (define (analyze-lexicals x)
-  ;; parents: lambda -> parent
-  ;;  useful when we see a closed-over var, so we can calculate its
-  ;;  coordinates (depth and index).
-  ;; bindings: lambda -> (sym ...)
-  ;;  useful for two reasons: one, so we know how much space to allocate
-  ;;  when we go into a lambda; and two, so that we know when to stop,
-  ;;  when looking for closed-over vars.
-  ;; heaps: sym -> lambda
-  ;;  allows us to heapify vars in an O(1) fashion
+  ;; bound-vars: lambda -> (sym ...)
+  ;;  all identifiers bound within a lambda
+  ;; free-vars: lambda -> (sym ...)
+  ;;  all identifiers referenced in a lambda, but not bound
+  ;;  NB, this includes identifiers referenced by contained lambdas
+  ;; assigned: sym -> #t
+  ;;  variables that are assigned
   ;; refcounts: sym -> count
-  ;;  allows us to detect the or-expansion an O(1) time
-
-  (define (find-heap sym parent)
-    ;; fixme: check displaced lexicals here?
-    (if (memq sym (hashq-ref bindings parent))
-        parent
-        (find-heap sym (hashq-ref parents parent))))
-
-  (define (analyze! x parent level)
-    (define (step y) (analyze! y parent level))
-    (define (recur x parent) (analyze! x parent (1+ level)))
+  ;;  allows us to detect the or-expansion in O(1) time
+  
+  ;; returns variables referenced in expr
+  (define (analyze! x proc)
+    (define (step y) (analyze! y proc))
+    (define (recur x new-proc) (analyze! x new-proc))
     (record-case x
       ((<application> proc args)
-       (step proc) (for-each step args))
+       (apply lset-union eq? (step proc) (map step args)))
 
       ((<conditional> test then else)
-       (step test) (step then) (step else))
+       (lset-union eq? (step test) (step then) (step else)))
 
       ((<lexical-ref> name gensym)
        (hashq-set! refcounts gensym (1+ (hashq-ref refcounts gensym 0)))
-       (if (and (not (memq gensym (hashq-ref bindings parent)))
-                (not (hashq-ref heaps gensym)))
-           (hashq-set! heaps gensym (find-heap gensym parent))))
+       (list gensym))
       
       ((<lexical-set> name gensym exp)
-       (step exp)
-       (if (not (hashq-ref heaps gensym))
-           (hashq-set! heaps gensym (find-heap gensym parent))))
+       (hashq-set! refcounts gensym (1+ (hashq-ref refcounts gensym 0)))
+       (hashq-set! assigned gensym #t)
+       (lset-adjoin eq? (step exp) gensym))
       
       ((<module-set> mod name public? exp)
        (step exp))
@@ -102,157 +143,168 @@
        (step exp))
       
       ((<sequence> exps)
-       (for-each step exps))
+       (apply lset-union eq? (map step exps)))
       
       ((<lambda> vars meta body)
-       (hashq-set! parents x parent)
-       (hashq-set! bindings x
-                   (let rev* ((vars vars) (out '()))
-                     (cond ((null? vars) out)
-                           ((pair? vars) (rev* (cdr vars)
-                                               (cons (car vars) out)))
-                           (else (cons vars out)))))
-       (recur body x)
-       (hashq-set! bindings x (reverse! (hashq-ref bindings x))))
-
+       (let ((locally-bound (let rev* ((vars vars) (out '()))
+                              (cond ((null? vars) out)
+                                    ((pair? vars) (rev* (cdr vars)
+                                                        (cons (car vars) out)))
+                                    (else (cons vars out))))))
+         (hashq-set! bound-vars x locally-bound)
+         (let* ((referenced (recur body x))
+                (free (lset-difference eq? referenced locally-bound))
+                (all-bound (reverse! (hashq-ref bound-vars x))))
+           (hashq-set! bound-vars x all-bound)
+           (hashq-set! free-vars x free)
+           free)))
+      
       ((<let> vars vals body)
-       (for-each step vals)
-       (hashq-set! bindings parent
-                   (append (reverse vars) (hashq-ref bindings parent)))
-       (step body))
+       (hashq-set! bound-vars proc
+                   (append (reverse vars) (hashq-ref bound-vars proc)))
+       (lset-difference eq?
+                        (apply lset-union eq? (step body) (map step vals))
+                        vars))
       
       ((<letrec> vars vals body)
-       (hashq-set! bindings parent
-                   (append (reverse vars) (hashq-ref bindings parent)))
-       (for-each step vals)
-       (step body))
-
+       (hashq-set! bound-vars proc
+                   (append (reverse vars) (hashq-ref bound-vars proc)))
+       (for-each (lambda (sym) (hashq-set! assigned sym #t)) vars)
+       (lset-difference eq?
+                        (apply lset-union eq? (step body) (map step vals))
+                        vars))
+      
       ((<let-values> vars exp body)
-       (hashq-set! bindings parent
-                   (let lp ((out (hashq-ref bindings parent)) (in vars))
+       (hashq-set! bound-vars proc
+                   (let lp ((out (hashq-ref bound-vars proc)) (in vars))
                      (if (pair? in)
                          (lp (cons (car in) out) (cdr in))
                          (if (null? in) out (cons in out)))))
-       (step exp)
-       (step body))
-
-      (else #f)))
-
-    (define (allocate-heap! binder)
-      (hashq-set! heap-indexes binder
-                  (1+ (hashq-ref heap-indexes binder -1))))
+       (lset-difference eq?
+                        (lset-union eq? (step exp) (step body))
+                        vars))
+      
+      (else '())))
+  
+  (define (allocate! x proc n)
+    (define (recur y) (allocate! y proc n))
+    (record-case x
+      ((<application> proc args)
+       (apply max (recur proc) (map recur args)))
 
-    (define (allocate! x level n)
-      (define (recur y) (allocate! y level n))
-      (record-case x
-        ((<application> proc args)
-         (apply max (recur proc) (map recur args)))
+      ((<conditional> test then else)
+       (max (recur test) (recur then) (recur else)))
 
-        ((<conditional> test then else)
-         (max (recur test) (recur then) (recur else)))
+      ((<lexical-set> name gensym exp)
+       (recur exp))
+      
+      ((<module-set> mod name public? exp)
+       (recur exp))
+      
+      ((<toplevel-set> name exp)
+       (recur exp))
+      
+      ((<toplevel-define> name exp)
+       (recur exp))
+      
+      ((<sequence> exps)
+       (apply max (map recur exps)))
+      
+      ((<lambda> vars meta body)
+       ;; allocate closure vars in order
+       (let lp ((c (hashq-ref free-vars x)) (n 0))
+         (if (pair? c)
+             (begin
+               (hashq-set! (hashq-ref allocation (car c))
+                           x
+                           `(#f ,(hashq-ref assigned (car c)) . ,n))
+               (lp (cdr c) (1+ n)))))
+      
+       (let ((nlocs
+              (let lp ((vars vars) (n 0))
+                (if (not (null? vars))
+                    ;; allocate args
+                    (let ((v (if (pair? vars) (car vars) vars)))
+                      (hashq-set! allocation v
+                                  (make-hashq
+                                   x `(#t ,(hashq-ref assigned v) . ,n)))
+                      (lp (if (pair? vars) (cdr vars) '()) (1+ n)))
+                    ;; allocate body, return number of additional locals
+                    (- (allocate! body x n) n))))
+             (free-addresses
+              (map (lambda (v)
+                     (hashq-ref (hashq-ref allocation v) proc))
+                   (hashq-ref free-vars x))))
+         ;; set procedure allocations
+         (hashq-set! allocation x (cons nlocs free-addresses)))
+       n)
 
-        ((<lexical-set> name gensym exp)
-         (recur exp))
-        
-        ((<module-set> mod name public? exp)
-         (recur exp))
-        
-        ((<toplevel-set> name exp)
-         (recur exp))
-        
-        ((<toplevel-define> name exp)
-         (recur exp))
-        
-        ((<sequence> exps)
-         (apply max (map recur exps)))
-        
-        ((<lambda> vars meta body)
-         (let lp ((vars vars) (n 0))
-           (if (null? vars)
-               (hashq-set! allocation x
-                           (let ((nlocs (- (allocate! body (1+ level) n) n)))
-                             (cons nlocs (1+ (hashq-ref heap-indexes x -1)))))
-               (let ((v (if (pair? vars) (car vars) vars)))
-                 (let ((binder (hashq-ref heaps v)))
+      ((<let> vars vals body)
+       (let ((nmax (apply max (map recur vals))))
+         (cond
+          ;; the `or' hack
+          ((and (conditional? body)
+                (= (length vars) 1)
+                (let ((v (car vars)))
+                  (and (not (hashq-ref assigned v))
+                       (= (hashq-ref refcounts v 0) 2)
+                       (lexical-ref? (conditional-test body))
+                       (eq? (lexical-ref-gensym (conditional-test body)) v)
+                       (lexical-ref? (conditional-then body))
+                       (eq? (lexical-ref-gensym (conditional-then body)) v))))
+           (hashq-set! allocation (car vars)
+                       (make-hashq proc `(#t #f . ,n)))
+           ;; the 1+ for this var
+           (max nmax (1+ n) (allocate! (conditional-else body) proc n)))
+          (else
+           (let lp ((vars vars) (n n))
+             (if (null? vars)
+                 (max nmax (allocate! body proc n))
+                 (let ((v (car vars)))
                    (hashq-set!
                     allocation v
-                    (if binder
-                        (cons* 'heap (1+ level) (allocate-heap! binder))
-                        (cons 'stack n))))
-                 (lp (if (pair? vars) (cdr vars) '()) (1+ n)))))
-         n)
+                    (make-hashq proc
+                                `(#t ,(hashq-ref assigned v) . ,n)))
+                   (lp (cdr vars) (1+ n)))))))))
+      
+      ((<letrec> vars vals body)
+       (let lp ((vars vars) (n n))
+         (if (null? vars)
+             (let ((nmax (apply max
+                                (map (lambda (x)
+                                       (allocate! x proc n))
+                                     vals))))
+               (max nmax (allocate! body proc n)))
+             (let ((v (car vars)))
+               (hashq-set!
+                allocation v
+                (make-hashq proc
+                            `(#t ,(hashq-ref assigned v) . ,n)))
+               (lp (cdr vars) (1+ n))))))
 
-        ((<let> vars vals body)
-         (let ((nmax (apply max (map recur vals))))
-           (cond
-            ;; the `or' hack
-            ((and (conditional? body)
-                  (= (length vars) 1)
-                  (let ((v (car vars)))
-                    (and (not (hashq-ref heaps v))
-                         (= (hashq-ref refcounts v 0) 2)
-                         (lexical-ref? (conditional-test body))
-                         (eq? (lexical-ref-gensym (conditional-test body)) v)
-                         (lexical-ref? (conditional-then body))
-                         (eq? (lexical-ref-gensym (conditional-then body)) 
v))))
-             (hashq-set! allocation (car vars) (cons 'stack n))
-             ;; the 1+ for this var
-             (max nmax (1+ n) (allocate! (conditional-else body) level n)))
-            (else
-             (let lp ((vars vars) (n n))
-               (if (null? vars)
-                   (max nmax (allocate! body level n))
-                   (let ((v (car vars)))
-                     (let ((binder (hashq-ref heaps v)))
-                       (hashq-set!
-                        allocation v
-                        (if binder
-                            (cons* 'heap level (allocate-heap! binder))
-                            (cons 'stack n)))
-                       (lp (cdr vars) (if binder n (1+ n)))))))))))
-        
-        ((<letrec> vars vals body)
+      ((<let-values> vars exp body)
+       (let ((nmax (recur exp)))
          (let lp ((vars vars) (n n))
            (if (null? vars)
-               (let ((nmax (apply max
-                                  (map (lambda (x)
-                                         (allocate! x level n))
-                                       vals))))
-                 (max nmax (allocate! body level n)))
-               (let ((v (car vars)))
-                 (let ((binder (hashq-ref heaps v)))
+               (max nmax (allocate! body proc n))
+               (let ((v (if (pair? vars) (car vars) vars)))
+                 (let ((v (car vars)))
                    (hashq-set!
                     allocation v
-                    (if binder
-                        (cons* 'heap level (allocate-heap! binder))
-                        (cons 'stack n)))
-                   (lp (cdr vars) (if binder n (1+ n))))))))
-
-        ((<let-values> vars exp body)
-         (let ((nmax (recur exp)))
-           (let lp ((vars vars) (n n))
-             (if (null? vars)
-                 (max nmax (allocate! body level n))
-                 (let ((v (if (pair? vars) (car vars) vars)))
-                   (let ((binder (hashq-ref heaps v)))
-                     (hashq-set!
-                      allocation v
-                      (if binder
-                          (cons* 'heap level (allocate-heap! binder))
-                          (cons 'stack n)))
-                     (lp (if (pair? vars) (cdr vars) '())
-                         (if binder n (1+ n)))))))))
-        
-        (else n)))
+                    (make-hashq proc
+                                `(#t ,(hashq-ref assigned v) . ,n)))
+                   (lp (cdr vars) (1+ n))))))))
+      
+      (else n)))
 
-  (define parents (make-hash-table))
-  (define bindings (make-hash-table))
-  (define heaps (make-hash-table))
+  (define bound-vars (make-hash-table))
+  (define free-vars (make-hash-table))
+  (define assigned (make-hash-table))
   (define refcounts (make-hash-table))
+  
   (define allocation (make-hash-table))
-  (define heap-indexes (make-hash-table))
-
-  (analyze! x #f -1)
-  (allocate! x -1 0)
+  
+  (analyze! x #f)
+  (allocate! x #f 0)
 
   allocation)
diff --git a/module/language/tree-il/compile-glil.scm 
b/module/language/tree-il/compile-glil.scm
index e0df038..f1d86e3 100644
--- a/module/language/tree-il/compile-glil.scm
+++ b/module/language/tree-il/compile-glil.scm
@@ -20,6 +20,7 @@
 
 (define-module (language tree-il compile-glil)
   #:use-module (system base syntax)
+  #:use-module (system base pmatch)
   #:use-module (ice-9 receive)
   #:use-module (language glil)
   #:use-module (system vm instruction)
@@ -34,8 +35,12 @@
 ;; basic degenerate-case reduction
 
 ;; allocation:
-;;  sym -> (local . index) | (heap level . index)
-;;  lambda -> (nlocs . nexts)
+;;  sym -> {lambda -> address}
+;;  lambda -> (nlocs . closure-vars)
+;;
+;; address := (local? boxed? . index)
+;; free-locs ::= ((sym0 . address0) (sym1 . address1) ...)
+;; free variable addresses are relative to parent proc.
 
 (define *comp-module* (make-fluid))
 
@@ -45,7 +50,7 @@
          (allocation (analyze-lexicals x)))
     (with-fluid* *comp-module* (or (and e (car e)) (current-module))
       (lambda ()
-        (values (flatten-lambda x -1 allocation)
+        (values (flatten-lambda x allocation)
                 (and e (cons (car e) (cddr e)))
                 e)))))
 
@@ -131,20 +136,19 @@
 
 (define (make-label) (gensym ":L"))
 
-(define (vars->bind-list ids vars allocation)
+(define (vars->bind-list ids vars allocation proc)
   (map (lambda (id v)
-         (let ((loc (hashq-ref allocation v)))
-           (case (car loc)
-             ((stack) (list id 'local (cdr loc)))
-             ((heap)  (list id 'external (cddr loc)))
-             (else (error "badness" id v loc)))))
+         (pmatch (hashq-ref (hashq-ref allocation v) proc)
+           ((#t ,boxed? . ,n)
+            (list id boxed? n))
+           (,x (error "badness" x))))
        ids
        vars))
 
-(define (emit-bindings src ids vars allocation emit-code)
+(define (emit-bindings src ids vars allocation proc emit-code)
   (if (pair? vars)
       (emit-code src (make-glil-bind
-                      (vars->bind-list ids vars allocation)))))
+                      (vars->bind-list ids vars allocation proc)))))
 
 (define (with-output-to-code proc)
   (let ((out '()))
@@ -155,7 +159,7 @@
     (proc emit-code)
     (reverse out)))
 
-(define (flatten-lambda x level allocation)
+(define (flatten-lambda x allocation)
   (receive (ids vars nargs nrest)
       (let lp ((ids (lambda-names x)) (vars (lambda-vars x))
                (oids '()) (ovars '()) (n 0))
@@ -166,31 +170,27 @@
                 (else (values (reverse (cons ids oids))
                               (reverse (cons vars ovars))
                               (1+ n) 1))))
-    (let ((nlocs (car (hashq-ref allocation x)))
-          (nexts (cdr (hashq-ref allocation x))))
+    (let ((nlocs (car (hashq-ref allocation x))))
       (make-glil-program
-       nargs nrest nlocs nexts (lambda-meta x)
+       nargs nrest nlocs (lambda-meta x)
        (with-output-to-code
         (lambda (emit-code)
           ;; write bindings and source debugging info
-          (emit-bindings #f ids vars allocation emit-code)
+          (emit-bindings #f ids vars allocation x emit-code)
           (if (lambda-src x)
               (emit-code #f (make-glil-source (lambda-src x))))
-
-          ;; copy args to the heap if necessary
-          (let lp ((in vars) (n 0))
-            (if (not (null? in))
-                (let ((loc (hashq-ref allocation (car in))))
-                  (case (car loc)
-                    ((heap)
-                     (emit-code #f (make-glil-local 'ref n))
-                     (emit-code #f (make-glil-external 'set 0 (cddr loc)))))
-                  (lp (cdr in) (1+ n)))))
-
+          ;; box args if necessary
+          (for-each
+           (lambda (v)
+             (pmatch (hashq-ref (hashq-ref allocation v) x)
+               ((#t #t . ,n)
+                (emit-code #f (make-glil-lexical #t #f 'ref n))
+                (emit-code #f (make-glil-lexical #t #t 'box n)))))
+           vars)
           ;; and here, here, dear reader: we compile.
-          (flatten (lambda-body x) (1+ level) allocation emit-code)))))))
+          (flatten (lambda-body x) allocation x emit-code)))))))
 
-(define (flatten x level allocation emit-code)
+(define (flatten x allocation proc emit-code)
   (define (emit-label label)
     (emit-code #f (make-glil-label label)))
   (define (emit-branch src inst label)
@@ -424,27 +424,21 @@
       ((<lexical-ref> src name gensym)
        (case context
          ((push vals tail)
-          (let ((loc (hashq-ref allocation gensym)))
-            (case (car loc)
-              ((stack)
-               (emit-code src (make-glil-local 'ref (cdr loc))))
-              ((heap)
-               (emit-code src (make-glil-external
-                               'ref (- level (cadr loc)) (cddr loc))))
-              (else (error "badness" x loc)))
-            (if (eq? context 'tail)
-                (emit-code #f (make-glil-call 'return 1)))))))
-
+          (pmatch (hashq-ref (hashq-ref allocation gensym) proc)
+            ((,local? ,boxed? . ,index)
+             (emit-code src (make-glil-lexical local? boxed? 'ref index)))
+            (,loc
+             (error "badness" x loc)))))
+       (case context
+         ((tail) (emit-code #f (make-glil-call 'return 1)))))
+      
       ((<lexical-set> src name gensym exp)
        (comp-push exp)
-       (let ((loc (hashq-ref allocation gensym)))
-         (case (car loc)
-           ((stack)
-            (emit-code src (make-glil-local 'set (cdr loc))))
-           ((heap)
-            (emit-code src (make-glil-external
-                            'set (- level (cadr loc)) (cddr loc))))
-           (else (error "badness" x loc))))
+       (pmatch (hashq-ref (hashq-ref allocation gensym) proc)
+         ((,local? ,boxed? . ,index)
+          (emit-code src (make-glil-lexical local? boxed? 'set index)))
+         (,loc
+          (error "badness" x loc)))
        (case context
          ((push vals)
           (emit-code #f (make-glil-void)))
@@ -495,39 +489,52 @@
           (emit-code #f (make-glil-call 'return 1)))))
 
       ((<lambda>)
-       (case context
-         ((push vals)
-          (emit-code #f (flatten-lambda x level allocation)))
-         ((tail)
-          (emit-code #f (flatten-lambda x level allocation))
-          (emit-code #f (make-glil-call 'return 1)))))
-
+       (let ((free-locs (cdr (hashq-ref allocation x))))
+         (case context
+           ((push vals tail)
+            (emit-code #f (flatten-lambda x allocation))
+            (if (not (null? free-locs))
+                (begin
+                  (for-each
+                   (lambda (loc)
+                     (pmatch loc
+                       ((,local? ,boxed? . ,n)
+                        (emit-code #f (make-glil-lexical local? #f 'ref n)))
+                       (else (error "what" x loc))))
+                   free-locs)
+                  (emit-code #f (make-glil-call 'vector (length free-locs)))
+                  (emit-code #f (make-glil-call 'make-closure 2))))
+            (if (eq? context 'tail)
+                (emit-code #f (make-glil-call 'return 1)))))))
+      
       ((<let> src names vars vals body)
        (for-each comp-push vals)
-       (emit-bindings src names vars allocation emit-code)
+       (emit-bindings src names vars allocation proc emit-code)
        (for-each (lambda (v)
-                   (let ((loc (hashq-ref allocation v)))
-                     (case (car loc)
-                       ((stack)
-                        (emit-code src (make-glil-local 'set (cdr loc))))
-                       ((heap)
-                        (emit-code src (make-glil-external 'set 0 (cddr loc))))
-                       (else (error "badness" x loc)))))
+                   (pmatch (hashq-ref (hashq-ref allocation v) proc)
+                     ((#t #f . ,n)
+                      (emit-code src (make-glil-lexical #t #f 'set n)))
+                     ((#t #t . ,n)
+                      (emit-code src (make-glil-lexical #t #t 'box n)))
+                     (,loc (error "badness" x loc))))
                  (reverse vars))
        (comp-tail body)
        (emit-code #f (make-glil-unbind)))
 
       ((<letrec> src names vars vals body)
+       (for-each (lambda (v)
+                   (pmatch (hashq-ref (hashq-ref allocation v) proc)
+                     ((#t #t . ,n)
+                      (emit-code src (make-glil-lexical #t #t 'empty-box n)))
+                     (,loc (error "badness" x loc))))
+                 vars)
        (for-each comp-push vals)
-       (emit-bindings src names vars allocation emit-code)
+       (emit-bindings src names vars allocation proc emit-code)
        (for-each (lambda (v)
-                   (let ((loc (hashq-ref allocation v)))
-                     (case (car loc)
-                       ((stack)
-                        (emit-code src (make-glil-local 'set (cdr loc))))
-                       ((heap)
-                        (emit-code src (make-glil-external 'set 0 (cddr loc))))
-                       (else (error "badness" x loc)))))
+                   (pmatch (hashq-ref (hashq-ref allocation v) proc)
+                     ((#t #t . ,n)
+                      (emit-code src (make-glil-lexical #t #t 'set n)))
+                     (,loc (error "badness" x loc))))
                  (reverse vars))
        (comp-tail body)
        (emit-code #f (make-glil-unbind)))
@@ -548,16 +555,15 @@
              (emit-code #f (make-glil-const 1))
              (emit-label MV)
              (emit-code src (make-glil-mv-bind
-                             (vars->bind-list names vars allocation)
+                             (vars->bind-list names vars allocation proc)
                              rest?))
              (for-each (lambda (v)
-                         (let ((loc (hashq-ref allocation v)))
-                           (case (car loc)
-                             ((stack)
-                              (emit-code src (make-glil-local 'set (cdr loc))))
-                             ((heap)
-                              (emit-code src (make-glil-external 'set 0 (cddr 
loc))))
-                             (else (error "badness" x loc)))))
+                         (pmatch (hashq-ref (hashq-ref allocation v) proc)
+                           ((#t #f . ,n)
+                            (emit-code src (make-glil-lexical #t #f 'set n)))
+                           ((#t #t . ,n)
+                            (emit-code src (make-glil-lexical #t #t 'box n)))
+                           (,loc (error "badness" x loc))))
                        (reverse vars))
              (comp-tail body)
              (emit-code #f (make-glil-unbind))))))))))
diff --git a/module/system/repl/command.scm b/module/system/repl/command.scm
index 6f45bd7..a99e1ba 100644
--- a/module/system/repl/command.scm
+++ b/module/system/repl/command.scm
@@ -386,7 +386,6 @@ Trace execution.
 
   -s    Display stack
   -l    Display local variables
-  -e    Display external variables
   -b    Bytecode level trace"
   (apply vm-trace (repl-vm repl)
          (repl-compile repl (repl-parse repl form))
diff --git a/module/system/vm/frame.scm b/module/system/vm/frame.scm
index 33a1e1b..332cd61 100644
--- a/module/system/vm/frame.scm
+++ b/module/system/vm/frame.scm
@@ -1,6 +1,6 @@
 ;;; Guile VM frame functions
 
-;;; Copyright (C) 2001 Free Software Foundation, Inc.
+;;; Copyright (C) 2001, 2009 Free Software Foundation, Inc.
 ;;; Copyright (C) 2005 Ludovic Court├Ęs  <address@hidden>
 ;;;
 ;;; This program is free software; you can redistribute it and/or modify
@@ -27,20 +27,20 @@
             vm-frame-program
             vm-frame-local-ref vm-frame-local-set!
             vm-frame-return-address vm-frame-mv-return-address
-            vm-frame-dynamic-link vm-frame-external-link
+            vm-frame-dynamic-link
             vm-frame-stack
 
 
             vm-frame-number vm-frame-address
-           make-frame-chain
-           print-frame print-frame-chain-as-backtrace
-           frame-arguments frame-local-variables frame-external-variables
-           frame-environment
-           frame-variable-exists? frame-variable-ref frame-variable-set!
-           frame-object-name
-           frame-local-ref frame-external-link frame-local-set!
-           frame-return-address frame-program
-           frame-dynamic-link heap-frame?))
+            make-frame-chain
+            print-frame print-frame-chain-as-backtrace
+            frame-arguments frame-local-variables
+            frame-environment
+            frame-variable-exists? frame-variable-ref frame-variable-set!
+            frame-object-name
+            frame-local-ref frame-local-set!
+            frame-return-address frame-program
+            frame-dynamic-link heap-frame?))
 
 (load-extension "libguile" "scm_init_frames")
 
@@ -158,24 +158,19 @@
         (l '() (cons (frame-local-ref frame n) l)))
        ((< n 0) l))))
 
-(define (frame-external-variables frame)
-  (frame-external-link frame))
-
-(define (frame-external-ref frame index)
-  (list-ref (frame-external-link frame) index))
-
-(define (frame-external-set! frame index val)
-  (list-set! (frame-external-link frame) index val))
-
 (define (frame-binding-ref frame binding)
-  (if (binding:extp binding)
-    (frame-external-ref frame (binding:index binding))
-    (frame-local-ref frame (binding:index binding))))
+  (let ((x (frame-local-ref frame (binding:index binding))))
+    (if (and (binding:boxed? binding) (variable? x))
+        (variable-ref x)
+        x)))
 
 (define (frame-binding-set! frame binding val)
-  (if (binding:extp binding)
-    (frame-external-set! frame (binding:index binding) val)
-    (frame-local-set! frame (binding:index binding) val)))
+  (if (binding:boxed? binding)
+      (let ((v (frame-local-ref frame binding)))
+        (if (variable? v)
+            (variable-set! v val)
+            (frame-local-set! frame binding (make-variable val))))
+      (frame-local-set! frame binding val)))
 
 ;; FIXME handle #f program-bindings return
 (define (frame-bindings frame addr)
diff --git a/module/system/vm/program.scm b/module/system/vm/program.scm
index 9db4a75..755c606 100644
--- a/module/system/vm/program.scm
+++ b/module/system/vm/program.scm
@@ -1,6 +1,6 @@
 ;;; Guile VM program functions
 
-;;; Copyright (C) 2001 Free Software Foundation, Inc.
+;;; Copyright (C) 2001, 2009 Free Software Foundation, Inc.
 ;;;
 ;;; This library is free software; you can redistribute it and/or
 ;;; modify it under the terms of the GNU Lesser General Public
@@ -21,9 +21,9 @@
 (define-module (system vm program)
   #:export (make-program
 
-            arity:nargs arity:nrest arity:nlocs arity:nexts
+            arity:nargs arity:nrest arity:nlocs
 
-            make-binding binding:name binding:extp binding:index
+            make-binding binding:name binding:boxed? binding:index
             binding:start binding:end
 
             source:addr source:line source:column source:file
@@ -31,21 +31,20 @@
             program-properties program-property program-documentation
             program-name program-arguments
            
-            program-arity program-external-set! program-meta
+            program-arity program-meta
             program-objcode program? program-objects
-            program-module program-base program-external))
+            program-module program-base program-free-variables))
 
 (load-extension "libguile" "scm_init_programs")
 
 (define arity:nargs car)
 (define arity:nrest cadr)
 (define arity:nlocs caddr)
-(define arity:nexts cadddr)
 
-(define (make-binding name extp index start end)
-  (list name extp index start end))
+(define (make-binding name boxed? index start end)
+  (list name boxed? index start end))
 (define (binding:name b) (list-ref b 0))
-(define (binding:extp b) (list-ref b 1))
+(define (binding:boxed? b) (list-ref b 1))
 (define (binding:index b) (list-ref b 2))
 (define (binding:start b) (list-ref b 3))
 (define (binding:end b) (list-ref b 4))
diff --git a/module/system/vm/trace.scm b/module/system/vm/trace.scm
index 6ff09a7..d8165f2 100644
--- a/module/system/vm/trace.scm
+++ b/module/system/vm/trace.scm
@@ -1,6 +1,6 @@
 ;;; Guile VM tracer
 
-;; Copyright (C) 2001 Free Software Foundation, Inc.
+;; Copyright (C) 2001, 2009 Free Software Foundation, Inc.
 
 ;;; This library is free software; you can redistribute it and/or
 ;;; modify it under the terms of the GNU Lesser General Public
@@ -54,8 +54,7 @@
       ((null? opts) (newline))
     (case (car opts)
       ((:s) (puts (truncate! (vm-fetch-stack vm) 3)))
-      ((:l) (puts (vm-fetch-locals vm)))
-      ((:e) (puts (vm-fetch-externals vm))))))
+      ((:l) (puts (vm-fetch-locals vm))))))
 
 (define (trace-apply vm)
   (if (vm-option vm 'trace-first)
diff --git a/test-suite/tests/asm-to-bytecode.test 
b/test-suite/tests/asm-to-bytecode.test
index 01ba846..d819a3b 100644
--- a/test-suite/tests/asm-to-bytecode.test
+++ b/test-suite/tests/asm-to-bytecode.test
@@ -85,28 +85,28 @@
                (vector 'load-keyword 0 0 3 (char->integer #\q) (char->integer 
#\u)
                        (char->integer #\x)))
 
-    (comp-test '(load-program 3 2 1 0 () 3 #f (make-int8 3) (return))
+    (comp-test '(load-program 3 2 1 () 3 #f (make-int8 3) (return))
                (list->vector
                 `(load-program
-                  3 2 1 0            ;; nargs, nrest, nlocs, nexts
+                  3 2 1 0            ;; nargs, nrest, nlocs, unused
                   ,@(u32->u8-list 3) ;; len
                   ,@(u32->u8-list 0) ;; metalen
                   make-int8 3
                   return)))
 
-    (comp-test '(load-program 3 2 1 0 () 3
-                              (load-program 3 2 1 0 () 3
+    (comp-test '(load-program 3 2 1 () 3
+                              (load-program 3 2 1 () 3
                                             #f
                                             (make-int8 3) (return))
                               (make-int8 3) (return))
                (list->vector
                 `(load-program
-                  3 2 1 0                   ;; nargs, nrest, nlocs, nexts
+                  3 2 1 0                   ;; nargs, nrest, nlocs, unused
                   ,@(u32->u8-list 3)        ;; len
                   ,@(u32->u8-list (+ 3 12)) ;; metalen
                   make-int8 3
                   return
-                  3 2 1 0                   ;; nargs, nrest, nlocs, nexts
+                  3 2 1 0                   ;; nargs, nrest, nlocs, unused
                   ,@(u32->u8-list 3)        ;; len
                   ,@(u32->u8-list 0)        ;; metalen
                   make-int8 3
diff --git a/test-suite/tests/tree-il.test b/test-suite/tests/tree-il.test
index ec410b5..6634dcd 100644
--- a/test-suite/tests/tree-il.test
+++ b/test-suite/tests/tree-il.test
@@ -64,21 +64,21 @@
 (with-test-prefix "void"
   (assert-tree-il->glil
    (void)
-   (program 0 0 0 0 () (void) (call return 1)))
+   (program 0 0 0 () (void) (call return 1)))
   (assert-tree-il->glil
    (begin (void) (const 1))
-   (program 0 0 0 0 () (const 1) (call return 1)))
+   (program 0 0 0 () (const 1) (call return 1)))
   (assert-tree-il->glil
    (apply (primitive +) (void) (const 1))
-   (program 0 0 0 0 () (void) (const 1) (call add 2) (call return 1))))
+   (program 0 0 0 () (void) (const 1) (call add 2) (call return 1))))
 
 (with-test-prefix "application"
   (assert-tree-il->glil
    (apply (toplevel foo) (const 1))
-   (program 0 0 0 0 () (toplevel ref foo) (const 1) (call goto/args 1)))
+   (program 0 0 0 () (toplevel ref foo) (const 1) (call goto/args 1)))
   (assert-tree-il->glil/pmatch
    (begin (apply (toplevel foo) (const 1)) (void))
-   (program 0 0 0 0 () (toplevel ref foo) (const 1) (mv-call 1 ,l1)
+   (program 0 0 0 () (toplevel ref foo) (const 1) (mv-call 1 ,l1)
             (call drop 1) (branch br ,l2)
             (label ,l3) (mv-bind () #f) (unbind)
             (label ,l4)
@@ -86,26 +86,26 @@
    (and (eq? l1 l3) (eq? l2 l4)))
   (assert-tree-il->glil
    (apply (toplevel foo) (apply (toplevel bar)))
-   (program 0 0 0 0 () (toplevel ref foo) (toplevel ref bar) (call call 0)
+   (program 0 0 0 () (toplevel ref foo) (toplevel ref bar) (call call 0)
             (call goto/args 1))))
 
 (with-test-prefix "conditional"
   (assert-tree-il->glil/pmatch
    (if (const #t) (const 1) (const 2))
-   (program 0 0 0 0 () (const #t) (branch br-if-not ,l1)
+   (program 0 0 0 () (const #t) (branch br-if-not ,l1)
             (const 1) (call return 1)
             (label ,l2) (const 2) (call return 1))
    (eq? l1 l2))
   
   (assert-tree-il->glil/pmatch
    (begin (if (const #t) (const 1) (const 2)) (const #f))
-   (program 0 0 0 0 () (const #t) (branch br-if-not ,l1) (branch br ,l2)
+   (program 0 0 0 () (const #t) (branch br-if-not ,l1) (branch br ,l2)
             (label ,l3) (label ,l4) (const #f) (call return 1))
    (eq? l1 l3) (eq? l2 l4))
 
   (assert-tree-il->glil/pmatch
    (apply (primitive null?) (if (const #t) (const 1) (const 2)))
-   (program 0 0 0 0 () (const #t) (branch br-if-not ,l1)
+   (program 0 0 0 () (const #t) (branch br-if-not ,l1)
             (const 1) (branch br ,l2)
                     (label ,l3) (const 2) (label ,l4)
                     (call null? 1) (call return 1))
@@ -114,279 +114,281 @@
 (with-test-prefix "primitive-ref"
   (assert-tree-il->glil
    (primitive +)
-   (program 0 0 0 0 () (toplevel ref +) (call return 1)))
+   (program 0 0 0 () (toplevel ref +) (call return 1)))
 
   (assert-tree-il->glil
    (begin (primitive +) (const #f))
-   (program 0 0 0 0 () (const #f) (call return 1)))
+   (program 0 0 0 () (const #f) (call return 1)))
 
   (assert-tree-il->glil
    (apply (primitive null?) (primitive +))
-   (program 0 0 0 0 () (toplevel ref +) (call null? 1)
+   (program 0 0 0 () (toplevel ref +) (call null? 1)
             (call return 1))))
 
 (with-test-prefix "lexical refs"
   (assert-tree-il->glil
    (let (x) (y) ((const 1)) (lexical x y))
-   (program 0 0 1 0 ()
-            (const 1) (bind (x local 0)) (local set 0)
-            (local ref 0) (call return 1)
+   (program 0 0 1 ()
+            (const 1) (bind (x #f 0)) (lexical #t #f set 0)
+            (lexical #t #f ref 0) (call return 1)
             (unbind)))
 
   (assert-tree-il->glil
    (let (x) (y) ((const 1)) (begin (lexical x y) (const #f)))
-   (program 0 0 1 0 ()
-            (const 1) (bind (x local 0)) (local set 0)
+   (program 0 0 1 ()
+            (const 1) (bind (x #f 0)) (lexical #t #f set 0)
             (const #f) (call return 1)
             (unbind)))
 
   (assert-tree-il->glil
    (let (x) (y) ((const 1)) (apply (primitive null?) (lexical x y)))
-   (program 0 0 1 0 ()
-            (const 1) (bind (x local 0)) (local set 0)
-            (local ref 0) (call null? 1) (call return 1)
+   (program 0 0 1 ()
+            (const 1) (bind (x #f 0)) (lexical #t #f set 0)
+            (lexical #t #f ref 0) (call null? 1) (call return 1)
             (unbind))))
 
 (with-test-prefix "lexical sets"
   (assert-tree-il->glil
    (let (x) (y) ((const 1)) (set! (lexical x y) (const 2)))
-   (program 0 0 0 1 ()
-            (const 1) (bind (x external 0)) (external set 0 0)
-            (const 2) (external set 0 0) (void) (call return 1)
+   (program 0 0 1 ()
+            (const 1) (bind (x #t 0)) (lexical #t #t box 0)
+            (const 2) (lexical #t #t set 0) (void) (call return 1)
             (unbind)))
 
   (assert-tree-il->glil
    (let (x) (y) ((const 1)) (begin (set! (lexical x y) (const 2)) (const #f)))
-   (program 0 0 0 1 ()
-            (const 1) (bind (x external 0)) (external set 0 0)
-            (const 2) (external set 0 0) (const #f) (call return 1)
+   (program 0 0 1 ()
+            (const 1) (bind (x #t 0)) (lexical #t #t box 0)
+            (const 2) (lexical #t #t set 0) (const #f) (call return 1)
             (unbind)))
 
   (assert-tree-il->glil
    (let (x) (y) ((const 1))
      (apply (primitive null?) (set! (lexical x y) (const 2))))
-   (program 0 0 0 1 ()
-            (const 1) (bind (x external 0)) (external set 0 0)
-            (const 2) (external set 0 0) (void) (call null? 1) (call return 1)
+   (program 0 0 1 ()
+            (const 1) (bind (x #t 0)) (lexical #t #t box 0)
+            (const 2) (lexical #t #t set 0) (void) (call null? 1) (call return 
1)
             (unbind))))
 
 (with-test-prefix "module refs"
   (assert-tree-il->glil
    (@ (foo) bar)
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (module public ref (foo) bar)
             (call return 1)))
 
   (assert-tree-il->glil
    (begin (@ (foo) bar) (const #f))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (module public ref (foo) bar) (call drop 1)
             (const #f) (call return 1)))
 
   (assert-tree-il->glil
    (apply (primitive null?) (@ (foo) bar))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (module public ref (foo) bar)
             (call null? 1) (call return 1)))
 
   (assert-tree-il->glil
    (@@ (foo) bar)
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (module private ref (foo) bar)
             (call return 1)))
 
   (assert-tree-il->glil
    (begin (@@ (foo) bar) (const #f))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (module private ref (foo) bar) (call drop 1)
             (const #f) (call return 1)))
 
   (assert-tree-il->glil
    (apply (primitive null?) (@@ (foo) bar))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (module private ref (foo) bar)
             (call null? 1) (call return 1))))
 
 (with-test-prefix "module sets"
   (assert-tree-il->glil
    (set! (@ (foo) bar) (const 2))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (module public set (foo) bar)
             (void) (call return 1)))
 
   (assert-tree-il->glil
    (begin (set! (@ (foo) bar) (const 2)) (const #f))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (module public set (foo) bar)
             (const #f) (call return 1)))
 
   (assert-tree-il->glil
    (apply (primitive null?) (set! (@ (foo) bar) (const 2)))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (module public set (foo) bar)
             (void) (call null? 1) (call return 1)))
 
   (assert-tree-il->glil
    (set! (@@ (foo) bar) (const 2))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (module private set (foo) bar)
             (void) (call return 1)))
 
   (assert-tree-il->glil
    (begin (set! (@@ (foo) bar) (const 2)) (const #f))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (module private set (foo) bar)
             (const #f) (call return 1)))
 
   (assert-tree-il->glil
    (apply (primitive null?) (set! (@@ (foo) bar) (const 2)))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (module private set (foo) bar)
             (void) (call null? 1) (call return 1))))
 
 (with-test-prefix "toplevel refs"
   (assert-tree-il->glil
    (toplevel bar)
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (toplevel ref bar)
             (call return 1)))
 
   (assert-tree-il->glil
    (begin (toplevel bar) (const #f))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (toplevel ref bar) (call drop 1)
             (const #f) (call return 1)))
 
   (assert-tree-il->glil
    (apply (primitive null?) (toplevel bar))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (toplevel ref bar)
             (call null? 1) (call return 1))))
 
 (with-test-prefix "toplevel sets"
   (assert-tree-il->glil
    (set! (toplevel bar) (const 2))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (toplevel set bar)
             (void) (call return 1)))
 
   (assert-tree-il->glil
    (begin (set! (toplevel bar) (const 2)) (const #f))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (toplevel set bar)
             (const #f) (call return 1)))
 
   (assert-tree-il->glil
    (apply (primitive null?) (set! (toplevel bar) (const 2)))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (toplevel set bar)
             (void) (call null? 1) (call return 1))))
 
 (with-test-prefix "toplevel defines"
   (assert-tree-il->glil
    (define bar (const 2))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (toplevel define bar)
             (void) (call return 1)))
 
   (assert-tree-il->glil
    (begin (define bar (const 2)) (const #f))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (toplevel define bar)
             (const #f) (call return 1)))
 
   (assert-tree-il->glil
    (apply (primitive null?) (define bar (const 2)))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (toplevel define bar)
             (void) (call null? 1) (call return 1))))
 
 (with-test-prefix "constants"
   (assert-tree-il->glil
    (const 2)
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (call return 1)))
 
   (assert-tree-il->glil
    (begin (const 2) (const #f))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const #f) (call return 1)))
 
   (assert-tree-il->glil
    (apply (primitive null?) (const 2))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (call null? 1) (call return 1))))
 
 (with-test-prefix "lambda"
   (assert-tree-il->glil
    (lambda (x) (y) () (const 2))
-   (program 0 0 0 0 ()
-            (program 1 0 0 0 ()
-                     (bind (x local 0))
+   (program 0 0 0 ()
+            (program 1 0 0 ()
+                     (bind (x #f 0))
                      (const 2) (call return 1))
             (call return 1)))
 
   (assert-tree-il->glil
    (lambda (x x1) (y y1) () (const 2))
-   (program 0 0 0 0 ()
-            (program 2 0 0 0 ()
-                     (bind (x local 0) (x1 local 1))
+   (program 0 0 0 ()
+            (program 2 0 0 ()
+                     (bind (x #f 0) (x1 #f 1))
                      (const 2) (call return 1))
             (call return 1)))
 
   (assert-tree-il->glil
    (lambda x y () (const 2))
-   (program 0 0 0 0 ()
-            (program 1 1 0 0 ()
-                     (bind (x local 0))
+   (program 0 0 0 ()
+            (program 1 1 0 ()
+                     (bind (x #f 0))
                      (const 2) (call return 1))
             (call return 1)))
 
   (assert-tree-il->glil
    (lambda (x . x1) (y . y1) () (const 2))
-   (program 0 0 0 0 ()
-            (program 2 1 0 0 ()
-                     (bind (x local 0) (x1 local 1))
+   (program 0 0 0 ()
+            (program 2 1 0 ()
+                     (bind (x #f 0) (x1 #f 1))
                      (const 2) (call return 1))
             (call return 1)))
 
   (assert-tree-il->glil
    (lambda (x . x1) (y . y1) () (lexical x y))
-   (program 0 0 0 0 ()
-            (program 2 1 0 0 ()
-                     (bind (x local 0) (x1 local 1))
-                     (local ref 0) (call return 1))
+   (program 0 0 0 ()
+            (program 2 1 0 ()
+                     (bind (x #f 0) (x1 #f 1))
+                     (lexical #t #f ref 0) (call return 1))
             (call return 1)))
 
   (assert-tree-il->glil
    (lambda (x . x1) (y . y1) () (lexical x1 y1))
-   (program 0 0 0 0 ()
-            (program 2 1 0 0 ()
-                     (bind (x local 0) (x1 local 1))
-                     (local ref 1) (call return 1))
+   (program 0 0 0 ()
+            (program 2 1 0 ()
+                     (bind (x #f 0) (x1 #f 1))
+                     (lexical #t #f ref 1) (call return 1))
             (call return 1)))
 
   (assert-tree-il->glil
    (lambda (x) (x1) () (lambda (y) (y1) () (lexical x x1)))
-   (program 0 0 0 0 ()
-            (program 1 0 0 1 ()
-                     (bind (x external 0))
-                     (local ref 0) (external set 0 0)
-                     (program 1 0 0 0 ()
-                              (bind (y local 0))
-                              (external ref 1 0) (call return 1))
+   (program 0 0 0 ()
+            (program 1 0 0 ()
+                     (bind (x #f 0))
+                     (program 1 0 0 ()
+                              (bind (y #f 0))
+                              (lexical #f #f ref 0) (call return 1))
+                     (lexical #t #f ref 0)
+                     (call vector 1)
+                     (call make-closure 2)
                      (call return 1))
             (call return 1))))
 
 (with-test-prefix "sequence"
   (assert-tree-il->glil
    (begin (begin (const 2) (const #f)) (const #t))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const #t) (call return 1)))
 
   (assert-tree-il->glil
    (apply (primitive null?) (begin (const #f) (const 2)))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (const 2) (call null? 1) (call return 1))))
 
 ;; FIXME: binding info for or-hacked locals might bork the disassembler,
@@ -398,13 +400,13 @@
             (lexical x y)
             (let (a) (b) ((const 2))
                  (lexical a b))))
-   (program 0 0 1 0 ()
-            (const 1) (bind (x local 0)) (local set 0)
-            (local ref 0) (branch br-if-not ,l1)
-            (local ref 0) (call return 1)
+   (program 0 0 1 ()
+            (const 1) (bind (x #f 0)) (lexical #t #f set 0)
+            (lexical #t #f ref 0) (branch br-if-not ,l1)
+            (lexical #t #f ref 0) (call return 1)
             (label ,l2)
-            (const 2) (bind (a local 0)) (local set 0)
-            (local ref 0) (call return 1)
+            (const 2) (bind (a #f 0)) (lexical #t #f set 0)
+            (lexical #t #f ref 0) (call return 1)
             (unbind)
             (unbind))
    (eq? l1 l2))
@@ -415,13 +417,13 @@
             (lexical x y)
             (let (a) (b) ((const 2))
                  (lexical x y))))
-   (program 0 0 2 0 ()
-            (const 1) (bind (x local 0)) (local set 0)
-            (local ref 0) (branch br-if-not ,l1)
-            (local ref 0) (call return 1)
+   (program 0 0 2 ()
+            (const 1) (bind (x #f 0)) (lexical #t #f set 0)
+            (lexical #t #f ref 0) (branch br-if-not ,l1)
+            (lexical #t #f ref 0) (call return 1)
             (label ,l2)
-            (const 2) (bind (a local 1)) (local set 1)
-            (local ref 0) (call return 1)
+            (const 2) (bind (a #f 1)) (lexical #t #f set 1)
+            (lexical #t #f ref 0) (call return 1)
             (unbind)
             (unbind))
    (eq? l1 l2)))
@@ -429,10 +431,10 @@
 (with-test-prefix "apply"
   (assert-tree-il->glil
    (apply (primitive @apply) (toplevel foo) (toplevel bar))
-   (program 0 0 0 0 () (toplevel ref foo) (toplevel ref bar) (call goto/apply 
2)))
+   (program 0 0 0 () (toplevel ref foo) (toplevel ref bar) (call goto/apply 
2)))
   (assert-tree-il->glil/pmatch
    (begin (apply (primitive @apply) (toplevel foo) (toplevel bar)) (void))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (toplevel ref apply) (toplevel ref foo) (toplevel ref bar) 
(mv-call 2 ,l1)
             (call drop 1) (branch br ,l2) (label ,l3) (mv-bind () #f) (unbind)
             (label ,l4)
@@ -440,7 +442,7 @@
    (and (eq? l1 l3) (eq? l2 l4)))
   (assert-tree-il->glil
    (apply (toplevel foo) (apply (toplevel @apply) (toplevel bar) (toplevel 
baz)))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (toplevel ref foo)
             (toplevel ref bar) (toplevel ref baz) (call apply 2)
             (call goto/args 1))))
@@ -448,10 +450,10 @@
 (with-test-prefix "call/cc"
   (assert-tree-il->glil
    (apply (primitive @call-with-current-continuation) (toplevel foo))
-   (program 0 0 0 0 () (toplevel ref foo) (call goto/cc 1)))
+   (program 0 0 0 () (toplevel ref foo) (call goto/cc 1)))
   (assert-tree-il->glil/pmatch
    (begin (apply (primitive @call-with-current-continuation) (toplevel foo)) 
(void))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (toplevel ref call-with-current-continuation) (toplevel ref foo) 
(mv-call 1 ,l1)
             (call drop 1) (branch br ,l2) (label ,l3) (mv-bind () #f) (unbind)
             (label ,l4)
@@ -460,7 +462,7 @@
   (assert-tree-il->glil
    (apply (toplevel foo)
           (apply (toplevel @call-with-current-continuation) (toplevel bar)))
-   (program 0 0 0 0 ()
+   (program 0 0 0 ()
             (toplevel ref foo)
             (toplevel ref bar) (call call/cc 1)
             (call goto/args 1))))


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