disass.el 8.82 KB
Newer Older
Eric S. Raymond's avatar
Eric S. Raymond committed
1 2
;;; disass.el --- disassembler for compiled Emacs Lisp code

Erik Naggum's avatar
Erik Naggum committed
3
;; Copyright (C) 1986, 1991 Free Software Foundation, Inc.
Eric S. Raymond's avatar
Eric S. Raymond committed
4

Eric S. Raymond's avatar
Eric S. Raymond committed
5 6 7
;; Author: Doug Cutting <doug@csli.stanford.edu>
;;	Jamie Zawinski <jwz@lucid.com>
;; Maintainer: Jamie Zawinski <jwz@lucid.com>
Eric S. Raymond's avatar
Eric S. Raymond committed
8
;; Keywords: internal
Eric S. Raymond's avatar
Eric S. Raymond committed
9

Jim Blandy's avatar
Jim Blandy committed
10 11 12 13
;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
Jim Blandy's avatar
Jim Blandy committed
14
;; the Free Software Foundation; either version 2, or (at your option)
Jim Blandy's avatar
Jim Blandy committed
15 16 17 18 19 20 21 22
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
Erik Naggum's avatar
Erik Naggum committed
23 24 25
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
Jim Blandy's avatar
Jim Blandy committed
26

Eric S. Raymond's avatar
Eric S. Raymond committed
27 28
;;; Commentary:

29 30 31 32 33 34 35 36
;; The single entry point, `disassemble', disassembles a code object generated
;; by the Emacs Lisp byte-compiler.  This doesn't invert the compilation
;; operation, not by a long shot, but it's useful for debugging.

;;
;; Original version by Doug Cutting (doug@csli.stanford.edu)
;; Substantially modified by Jamie Zawinski <jwz@lucid.com> for
;; the new lapcode-based byte compiler.
Eric S. Raymond's avatar
Eric S. Raymond committed
37 38

;;; Code:
Jim Blandy's avatar
Jim Blandy committed
39 40

;;; The variable byte-code-vector is defined by the new bytecomp.el.
Jim Blandy's avatar
Jim Blandy committed
41 42
;;; The function byte-decompile-lapcode is defined in byte-opt.el.
;;; Since we don't use byte-decompile-lapcode, let's try not loading byte-opt.
43
(require 'byte-compile "bytecomp")
Jim Blandy's avatar
Jim Blandy committed
44

45
(defvar disassemble-column-1-indent 8 "*")
Jim Blandy's avatar
Jim Blandy committed
46 47 48 49
(defvar disassemble-column-2-indent 10 "*")

(defvar disassemble-recursive-indent 3 "*")

Jim Blandy's avatar
Jim Blandy committed
50
;;;###autoload
Jim Blandy's avatar
Jim Blandy committed
51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82
(defun disassemble (object &optional buffer indent interactive-p)
  "Print disassembled code for OBJECT in (optional) BUFFER.
OBJECT can be a symbol defined as a function, or a function itself
\(a lambda expression or a compiled-function object).
If OBJECT is not already compiled, we compile it, but do not
redefine OBJECT if it is a symbol."
  (interactive (list (intern (completing-read "Disassemble function: "
					      obarray 'fboundp t))
		     nil 0 t))
  (if (eq (car-safe object) 'byte-code)
      (setq object (list 'lambda () object)))
  (or indent (setq indent 0))		;Default indent to zero
  (save-excursion
    (if (or interactive-p (null buffer))
	(with-output-to-temp-buffer "*Disassemble*"
	  (set-buffer "*Disassemble*")
	  (disassemble-internal object indent (not interactive-p)))
      (set-buffer buffer)
      (disassemble-internal object indent nil)))
  nil)


(defun disassemble-internal (obj indent interactive-p)
  (let ((macro 'nil)
	(name 'nil)
	(doc 'nil)
	args)
    (while (symbolp obj)
      (setq name obj
	    obj (symbol-function obj)))
    (if (subrp obj)
	(error "Can't disassemble #<subr %s>" name))
83 84 85 86
    (if (and (listp obj) (eq (car obj) 'autoload))
	(progn
	  (load (nth 1 obj))
	  (setq obj (symbol-function name))))
Jim Blandy's avatar
Jim Blandy committed
87 88 89
    (if (eq (car-safe obj) 'macro)	;handle macros
	(setq macro t
	      obj (cdr obj)))
90 91
    (if (and (listp obj) (eq (car obj) 'byte-code))
	(setq obj (list 'lambda nil obj)))	
Jim Blandy's avatar
Jim Blandy committed
92 93 94 95 96 97 98 99 100 101 102 103 104 105 106
    (if (and (listp obj) (not (eq (car obj) 'lambda)))
	(error "not a function"))
    (if (consp obj)
	(if (assq 'byte-code obj)
	    nil
	  (if interactive-p (message (if name
					 "Compiling %s's definition..."
				       "Compiling definition...")
				     name))
	  (setq obj (byte-compile obj))
	  (if interactive-p (message "Done compiling.  Disassembling..."))))
    (cond ((consp obj)
	   (setq obj (cdr obj))		;throw lambda away
	   (setq args (car obj))	;save arg list
	   (setq obj (cdr obj)))
107 108 109
	  ((byte-code-function-p obj)
	   (setq args (aref obj 0)))
          (t (error "Compilation failed")))
Jim Blandy's avatar
Jim Blandy committed
110 111 112 113 114 115 116 117 118
    (if (zerop indent) ; not a nested function
	(progn
	  (indent-to indent)
	  (insert (format "byte code%s%s%s:\n"
			  (if (or macro name) " for" "")
			  (if macro " macro" "")
			  (if name (format " %s" name) "")))))
    (let ((doc (if (consp obj)
		   (and (stringp (car obj)) (car obj))
119 120
		 ;; Use documentation to get lazy-loaded doc string
		 (documentation obj t))))
Jim Blandy's avatar
Jim Blandy committed
121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153
      (if (and doc (stringp doc))
	  (progn (and (consp obj) (setq obj (cdr obj)))
		 (indent-to indent)
		 (princ "  doc:  " (current-buffer))
		 (if (string-match "\n" doc)
		     (setq doc (concat (substring doc 0 (match-beginning 0))
				       " ...")))
		 (insert doc "\n"))))
    (indent-to indent)
    (insert "  args: ")
    (prin1 args (current-buffer))
    (insert "\n")
    (let ((interactive (cond ((consp obj)
			      (assq 'interactive obj))
			     ((> (length obj) 5)
			      (list 'interactive (aref obj 5))))))
      (if interactive
	  (progn
	    (setq interactive (nth 1 interactive))
	    (if (eq (car-safe (car-safe obj)) 'interactive)
		(setq obj (cdr obj)))
	    (indent-to indent)
	    (insert " interactive: ")
	    (if (eq (car-safe interactive) 'byte-code)
		(progn
		  (insert "\n")
		  (disassemble-1 interactive
				 (+ indent disassemble-recursive-indent)))
	      (let ((print-escape-newlines t))
		(prin1 interactive (current-buffer))))
	    (insert "\n"))))
    (cond ((and (consp obj) (assq 'byte-code obj))
	   (disassemble-1 (assq 'byte-code obj) indent))
Jim Blandy's avatar
Jim Blandy committed
154
	  ((byte-code-function-p obj)
Jim Blandy's avatar
Jim Blandy committed
155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171
	   (disassemble-1 obj indent))
	  (t
	   (insert "Uncompiled body:  ")
	   (let ((print-escape-newlines t))
	     (prin1 (if (cdr obj) (cons 'progn obj) (car obj))
		    (current-buffer))))))
  (if interactive-p
      (message "")))


(defun disassemble-1 (obj indent)
  "Prints the byte-code call OBJ in the current buffer.
OBJ should be a call to BYTE-CODE generated by the byte compiler."
  (let (bytes constvec)
    (if (consp obj)
	(setq bytes (car (cdr obj))		;the byte code
	      constvec (car (cdr (cdr obj))))	;constant vector
172 173
      ;; If it is lazy-loaded, load it now
      (fetch-bytecode obj)
174
      (setq bytes (aref obj 1)
Jim Blandy's avatar
Jim Blandy committed
175
	    constvec (aref obj 2)))
176
    (let ((lap (byte-decompile-bytecode (string-as-unibyte bytes) constvec))
177
	  op arg opname pc-value)
Jim Blandy's avatar
Jim Blandy committed
178 179 180 181 182 183 184
      (let ((tagno 0)
	    tmp
	    (lap lap))
	(while (setq tmp (assq 'TAG lap))
	  (setcar (cdr tmp) (setq tagno (1+ tagno)))
	  (setq lap (cdr (memq tmp lap)))))
      (while lap
185 186 187 188 189 190 191
	;; Take off the pc value of the next thing
	;; and put it in pc-value.
	(setq pc-value nil)
	(if (numberp (car lap))
	    (setq pc-value (car lap)
		  lap (cdr lap)))
	;; Fetch the next op and its arg.
Jim Blandy's avatar
Jim Blandy committed
192 193
	(setq op (car (car lap))
	      arg (cdr (car lap)))
194
	(setq lap (cdr lap))
Jim Blandy's avatar
Jim Blandy committed
195 196
	(indent-to indent)
	(if (eq 'TAG op)
197 198 199 200 201 202 203 204
	    (progn
	      ;; We have a label.  Display it, but first its pc value.
	      (if pc-value
		  (insert (format "%d:" pc-value)))
	      (insert (int-to-string (car arg))))
	  ;; We have an instruction.  Display its pc value first.
	  (if pc-value
	      (insert (format "%d" pc-value)))
Jim Blandy's avatar
Jim Blandy committed
205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228
	  (indent-to (+ indent disassemble-column-1-indent))
	  (if (and op
		   (string-match "^byte-" (setq opname (symbol-name op))))
	      (setq opname (substring opname 5))
	    (setq opname "<not-an-opcode>"))
	  (if (eq op 'byte-constant2)
	      (insert " #### shouldn't have seen constant2 here!\n  "))
	  (insert opname)
	  (indent-to (+ indent disassemble-column-1-indent
			disassemble-column-2-indent
			-1))
	  (insert " ")
	  (cond ((memq op byte-goto-ops)
		 (insert (int-to-string (nth 1 arg))))
		((memq op '(byte-call byte-unbind
			    byte-listN byte-concatN byte-insertN))
		 (insert (int-to-string arg)))
		((memq op '(byte-varref byte-varset byte-varbind))
		 (prin1 (car arg) (current-buffer)))
		((memq op '(byte-constant byte-constant2))
		 ;; it's a constant
		 (setq arg (car arg))
		 ;; but if the value of the constant is compiled code, then
		 ;; recursively disassemble it.
Jim Blandy's avatar
Jim Blandy committed
229
		 (cond ((or (byte-code-function-p arg)
Jim Blandy's avatar
Jim Blandy committed
230 231 232
			    (and (eq (car-safe arg) 'lambda)
				 (assq 'byte-code arg))
			    (and (eq (car-safe arg) 'macro)
Jim Blandy's avatar
Jim Blandy committed
233
				 (or (byte-code-function-p (cdr arg))
Jim Blandy's avatar
Jim Blandy committed
234 235
				     (and (eq (car-safe (cdr arg)) 'lambda)
					  (assq 'byte-code (cdr arg))))))
Jim Blandy's avatar
Jim Blandy committed
236
			(cond ((byte-code-function-p arg)
Jim Blandy's avatar
Jim Blandy committed
237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262
			       (insert "<compiled-function>\n"))
			      ((eq (car-safe arg) 'lambda)
			       (insert "<compiled lambda>"))
			      (t (insert "<compiled macro>\n")))
			(disassemble-internal
			 arg
			 (+ indent disassemble-recursive-indent 1)
			 nil))
		       ((eq (car-safe arg) 'byte-code)
			(insert "<byte code>\n")
			(disassemble-1	;recurse on byte-code object
			 arg
			 (+ indent disassemble-recursive-indent)))
		       ((eq (car-safe (car-safe arg)) 'byte-code)
			(insert "(<byte code>...)\n")
			(mapcar ;recurse on list of byte-code objects
			 '(lambda (obj)
			    (disassemble-1
			     obj
			     (+ indent disassemble-recursive-indent)))
			 arg))
		       (t
			;; really just a constant
			(let ((print-escape-newlines t))
			  (prin1 arg (current-buffer))))))
		)
263
	  (insert "\n")))))
Jim Blandy's avatar
Jim Blandy committed
264
  nil)
Eric S. Raymond's avatar
Eric S. Raymond committed
265

Richard M. Stallman's avatar
Richard M. Stallman committed
266 267
(provide 'disass)

Eric S. Raymond's avatar
Eric S. Raymond committed
268
;;; disass.el ends here