code.delx.au - gnu-emacs/blob - lisp/emacs-lisp/disass.el

   1 ;;; disass.el --- disassembler for compiled Emacs Lisp code
   2
   3 ;;; Copyright (C) 1986, 1991 Free Software Foundation, Inc.
   4
   5 ;; Author: Doug Cutting <doug@csli.stanford.edu>
   6 ;;      Jamie Zawinski <jwz@lucid.com>
   7 ;; Maintainer: Jamie Zawinski <jwz@lucid.com>
   8 ;; Keywords: internal
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software; you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation; either version 2, or (at your option)
  15 ;; any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  24 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; The single entry point, `disassemble', disassembles a code object generated
  29 ;; by the Emacs Lisp byte-compiler.  This doesn't invert the compilation
  30 ;; operation, not by a long shot, but it's useful for debugging.
  31
  32 ;;
  33 ;; Original version by Doug Cutting (doug@csli.stanford.edu)
  34 ;; Substantially modified by Jamie Zawinski <jwz@lucid.com> for
  35 ;; the new lapcode-based byte compiler.
  36
  37 ;;; Code:
  38
  39 ;;; The variable byte-code-vector is defined by the new bytecomp.el.
  40 ;;; The function byte-decompile-lapcode is defined in byte-opt.el.
  41 ;;; Since we don't use byte-decompile-lapcode, let's try not loading byte-opt.
  42 (require 'byte-compile "bytecomp")
  43
  44 (defvar disassemble-column-1-indent 5 "*")
  45 (defvar disassemble-column-2-indent 10 "*")
  46
  47 (defvar disassemble-recursive-indent 3 "*")
  48
  49 ;;;###autoload
  50 (defun disassemble (object &optional buffer indent interactive-p)
  51   "Print disassembled code for OBJECT in (optional) BUFFER.
  52 OBJECT can be a symbol defined as a function, or a function itself
  53 \(a lambda expression or a compiled-function object).
  54 If OBJECT is not already compiled, we compile it, but do not
  55 redefine OBJECT if it is a symbol."
  56   (interactive (list (intern (completing-read "Disassemble function: "
  57                                               obarray 'fboundp t))
  58                      nil 0 t))
  59   (if (eq (car-safe object) 'byte-code)
  60       (setq object (list 'lambda () object)))
  61   (or indent (setq indent 0))           ;Default indent to zero
  62   (save-excursion
  63     (if (or interactive-p (null buffer))
  64         (with-output-to-temp-buffer "*Disassemble*"
  65           (set-buffer "*Disassemble*")
  66           (disassemble-internal object indent (not interactive-p)))
  67       (set-buffer buffer)
  68       (disassemble-internal object indent nil)))
  69   nil)
  70
  71
  72 (defun disassemble-internal (obj indent interactive-p)
  73   (let ((macro 'nil)
  74         (name 'nil)
  75         (doc 'nil)
  76         args)
  77     (while (symbolp obj)
  78       (setq name obj
  79             obj (symbol-function obj)))
  80     (if (subrp obj)
  81         (error "Can't disassemble #<subr %s>" name))
  82     (if (eq (car-safe obj) 'macro)      ;handle macros
  83         (setq macro t
  84               obj (cdr obj)))
  85     (if (and (listp obj) (not (eq (car obj) 'lambda)))
  86         (error "not a function"))
  87     (if (consp obj)
  88         (if (assq 'byte-code obj)
  89             nil
  90           (if interactive-p (message (if name
  91                                          "Compiling %s's definition..."
  92                                        "Compiling definition...")
  93                                      name))
  94           (setq obj (byte-compile obj))
  95           (if interactive-p (message "Done compiling.  Disassembling..."))))
  96     (cond ((consp obj)
  97            (setq obj (cdr obj))         ;throw lambda away
  98            (setq args (car obj))        ;save arg list
  99            (setq obj (cdr obj)))
 100           (t
 101            (setq args (aref obj 0))))
 102     (if (zerop indent) ; not a nested function
 103         (progn
 104           (indent-to indent)
 105           (insert (format "byte code%s%s%s:\n"
 106                           (if (or macro name) " for" "")
 107                           (if macro " macro" "")
 108                           (if name (format " %s" name) "")))))
 109     (let ((doc (if (consp obj)
 110                    (and (stringp (car obj)) (car obj))
 111                  (and (> (length obj) 4) (aref obj 4)))))
 112       (if (and doc (stringp doc))
 113           (progn (and (consp obj) (setq obj (cdr obj)))
 114                  (indent-to indent)
 115                  (princ "  doc:  " (current-buffer))
 116                  (if (string-match "\n" doc)
 117                      (setq doc (concat (substring doc 0 (match-beginning 0))
 118                                        " ...")))
 119                  (insert doc "\n"))))
 120     (indent-to indent)
 121     (insert "  args: ")
 122     (prin1 args (current-buffer))
 123     (insert "\n")
 124     (let ((interactive (cond ((consp obj)
 125                               (assq 'interactive obj))
 126                              ((> (length obj) 5)
 127                               (list 'interactive (aref obj 5))))))
 128       (if interactive
 129           (progn
 130             (setq interactive (nth 1 interactive))
 131             (if (eq (car-safe (car-safe obj)) 'interactive)
 132                 (setq obj (cdr obj)))
 133             (indent-to indent)
 134             (insert " interactive: ")
 135             (if (eq (car-safe interactive) 'byte-code)
 136                 (progn
 137                   (insert "\n")
 138                   (disassemble-1 interactive
 139                                  (+ indent disassemble-recursive-indent)))
 140               (let ((print-escape-newlines t))
 141                 (prin1 interactive (current-buffer))))
 142             (insert "\n"))))
 143     (cond ((and (consp obj) (assq 'byte-code obj))
 144            (disassemble-1 (assq 'byte-code obj) indent))
 145           ((byte-code-function-p obj)
 146            (disassemble-1 obj indent))
 147           (t
 148            (insert "Uncompiled body:  ")
 149            (let ((print-escape-newlines t))
 150              (prin1 (if (cdr obj) (cons 'progn obj) (car obj))
 151                     (current-buffer))))))
 152   (if interactive-p
 153       (message "")))
 154
 155
 156 (defun disassemble-1 (obj indent)
 157   "Prints the byte-code call OBJ in the current buffer.
 158 OBJ should be a call to BYTE-CODE generated by the byte compiler."
 159   (let (bytes constvec)
 160     (if (consp obj)
 161         (setq bytes (car (cdr obj))             ;the byte code
 162               constvec (car (cdr (cdr obj))))   ;constant vector
 163       (setq bytes (aref obj 1)
 164             constvec (aref obj 2)))
 165     (let ((lap (byte-decompile-bytecode bytes constvec))
 166           op arg opname)
 167       (let ((tagno 0)
 168             tmp
 169             (lap lap))
 170         (while (setq tmp (assq 'TAG lap))
 171           (setcar (cdr tmp) (setq tagno (1+ tagno)))
 172           (setq lap (cdr (memq tmp lap)))))
 173       (while lap
 174         (setq op (car (car lap))
 175               arg (cdr (car lap)))
 176         (indent-to indent)
 177         (if (eq 'TAG op)
 178             (insert (int-to-string (car arg)) ":")
 179
 180           (indent-to (+ indent disassemble-column-1-indent))
 181           (if (and op
 182                    (string-match "^byte-" (setq opname (symbol-name op))))
 183               (setq opname (substring opname 5))
 184             (setq opname "<not-an-opcode>"))
 185           (if (eq op 'byte-constant2)
 186               (insert " #### shouldn't have seen constant2 here!\n  "))
 187           (insert opname)
 188           (indent-to (+ indent disassemble-column-1-indent
 189                         disassemble-column-2-indent
 190                         -1))
 191           (insert " ")
 192           (cond ((memq op byte-goto-ops)
 193                  (insert (int-to-string (nth 1 arg))))
 194                 ((memq op '(byte-call byte-unbind
 195                             byte-listN byte-concatN byte-insertN))
 196                  (insert (int-to-string arg)))
 197                 ((memq op '(byte-varref byte-varset byte-varbind))
 198                  (prin1 (car arg) (current-buffer)))
 199                 ((memq op '(byte-constant byte-constant2))
 200                  ;; it's a constant
 201                  (setq arg (car arg))
 202                  ;; but if the value of the constant is compiled code, then
 203                  ;; recursively disassemble it.
 204                  (cond ((or (byte-code-function-p arg)
 205                             (and (eq (car-safe arg) 'lambda)
 206                                  (assq 'byte-code arg))
 207                             (and (eq (car-safe arg) 'macro)
 208                                  (or (byte-code-function-p (cdr arg))
 209                                      (and (eq (car-safe (cdr arg)) 'lambda)
 210                                           (assq 'byte-code (cdr arg))))))
 211                         (cond ((byte-code-function-p arg)
 212                                (insert "<compiled-function>\n"))
 213                               ((eq (car-safe arg) 'lambda)
 214                                (insert "<compiled lambda>"))
 215                               (t (insert "<compiled macro>\n")))
 216                         (disassemble-internal
 217                          arg
 218                          (+ indent disassemble-recursive-indent 1)
 219                          nil))
 220                        ((eq (car-safe arg) 'byte-code)
 221                         (insert "<byte code>\n")
 222                         (disassemble-1  ;recurse on byte-code object
 223                          arg
 224                          (+ indent disassemble-recursive-indent)))
 225                        ((eq (car-safe (car-safe arg)) 'byte-code)
 226                         (insert "(<byte code>...)\n")
 227                         (mapcar ;recurse on list of byte-code objects
 228                          '(lambda (obj)
 229                             (disassemble-1
 230                              obj
 231                              (+ indent disassemble-recursive-indent)))
 232                          arg))
 233                        (t
 234                         ;; really just a constant
 235                         (let ((print-escape-newlines t))
 236                           (prin1 arg (current-buffer))))))
 237                 )
 238           (insert "\n"))
 239         (setq lap (cdr lap)))))
 240   nil)
 241
 242 ;;; disass.el ends here