module/language/objcode/spec.scm

   1 ;;; Guile Lowlevel Intermediate Language
   2
   3 ;; Copyright (C) 2001, 2009 Free Software Foundation, Inc.
   4
   5 ;;;; This library is free software; you can redistribute it and/or
   6 ;;;; modify it under the terms of the GNU Lesser General Public
   7 ;;;; License as published by the Free Software Foundation; either
   8 ;;;; version 3 of the License, or (at your option) any later version.
   9 ;;;;
  10 ;;;; This library is distributed in the hope that it will be useful,
  11 ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 ;;;; Lesser General Public License for more details.
  14 ;;;;
  15 ;;;; You should have received a copy of the GNU Lesser General Public
  16 ;;;; License along with this library; if not, write to the Free Software
  17 ;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18
  19 ;;; Code:
  20
  21 (define-module (language objcode spec)
  22   #:use-module (system base language)
  23   #:use-module (system vm objcode)
  24   #:use-module (system vm program)
  25   #:export (objcode make-objcode-env))
  26
  27 (define (make-objcode-env module externals)
  28   (cons module externals))
  29
  30 (define (objcode-env-module env)
  31   (if env (car env) (current-module)))
  32
  33 (define (objcode-env-externals env)
  34   (and env (vector? (cdr env)) (cdr env)))
  35
  36 (define (objcode->value x e opts)
  37   (let ((thunk (make-program x #f (objcode-env-externals e))))
  38     (if e
  39         (save-module-excursion
  40          (lambda ()
  41            (set-current-module (objcode-env-module e))
  42            (values (thunk) #f e)))
  43         (values (thunk) #f e))))
  44
  45 ;; since locals are allocated on the stack and can have limited scope,
  46 ;; in many cases we use one local for more than one lexical variable. so
  47 ;; the returned locals set is a list, where element N of the list is
  48 ;; itself a list of bindings for local variable N.
  49 (define (collapse-locals locs)
  50   (let lp ((ret '()) (locs locs))
  51     (if (null? locs)
  52         (map cdr (sort! ret
  53                         (lambda (x y) (< (car x) (car y)))))
  54         (let ((b (car locs)))
  55           (cond
  56            ((assv-ref ret (binding:index b))
  57             => (lambda (bindings)
  58                  (append! bindings (list b))
  59                  (lp ret (cdr locs))))
  60            (else
  61             (lp (acons (binding:index b) (list b) ret)
  62                 (cdr locs))))))))
  63
  64 (define (decompile-value x env opts)
  65   (cond
  66    ((program? x)
  67     (let ((objs  (program-objects x))
  68           (meta  (program-meta x))
  69           (exts  (program-external x))
  70           (binds (program-bindings x))
  71           (srcs  (program-sources x))
  72           (nargs (arity:nargs (program-arity x))))
  73       (let ((blocs (and binds
  74                         (collapse-locals
  75                          (append (list-head binds nargs)
  76                                  (filter (lambda (x) (not (binding:extp x)))
  77                                          (list-tail binds nargs))))))
  78             (bexts (and binds
  79                         (filter binding:extp binds))))
  80         (values (program-objcode x)
  81                 `((objects . ,objs)
  82                   (meta    . ,(and meta (meta)))
  83                   (exts    . ,exts)
  84                   (blocs   . ,blocs)
  85                   (bexts   . ,bexts)
  86                   (sources . ,srcs))))))
  87    ((objcode? x)
  88     (values x #f))
  89    (else
  90     (error "can't decompile ~A: not a program or objcode" x))))
  91
  92 (define-language objcode
  93   #:title       "Guile Object Code"
  94   #:version     "0.3"
  95   #:reader      #f
  96   #:printer     write-objcode
  97   #:compilers   `((value . ,objcode->value))
  98   #:decompilers `((value . ,decompile-value))
  99   )