1 ;;; disass.el --- disassembler for compiled Emacs Lisp code
3 ;;; Copyright (C) 1986, 1991 Free Software Foundation, Inc.
5 ;; Author: Doug Cutting <doug@csli.stanford.edu>
6 ;; Jamie Zawinski <jwz@lucid.com>
7 ;; Maintainer: Jamie Zawinski <jwz@lucid.com>
10 ;; This file is part of GNU Emacs.
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)
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.
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.
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.
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.
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")
44 (defvar disassemble-column-1-indent 8 "*")
45 (defvar disassemble-column-2-indent 10 "*")
47 (defvar disassemble-recursive-indent 3 "*")
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: "
59 (if (eq (car-safe object) 'byte-code)
60 (setq object (list 'lambda () object)))
61 (or indent (setq indent 0)) ;Default indent to zero
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)))
68 (disassemble-internal object indent nil)))
72 (defun disassemble-internal (obj indent interactive-p)
79 obj (symbol-function obj)))
81 (error "Can't disassemble #<subr %s>" name))
82 (if (and (listp obj) (eq (car obj) 'autoload))
85 (setq obj (symbol-function name))))
86 (if (eq (car-safe obj) 'macro) ;handle macros
89 (if (and (listp obj) (eq (car obj) 'byte-code))
90 (setq obj (list 'lambda nil obj)))
91 (if (and (listp obj) (not (eq (car obj) 'lambda)))
92 (error "not a function"))
94 (if (assq 'byte-code obj)
96 (if interactive-p (message (if name
97 "Compiling %s's definition..."
98 "Compiling definition...")
100 (setq obj (byte-compile obj))
101 (if interactive-p (message "Done compiling. Disassembling..."))))
103 (setq obj (cdr obj)) ;throw lambda away
104 (setq args (car obj)) ;save arg list
105 (setq obj (cdr obj)))
107 (setq args (aref obj 0))))
108 (if (zerop indent) ; not a nested function
111 (insert (format "byte code%s%s%s:\n"
112 (if (or macro name) " for" "")
113 (if macro " macro" "")
114 (if name (format " %s" name) "")))))
115 (let ((doc (if (consp obj)
116 (and (stringp (car obj)) (car obj))
117 ;; Use documentation to get lazy-loaded doc string
118 (documentation obj t))))
119 (if (and doc (stringp doc))
120 (progn (and (consp obj) (setq obj (cdr obj)))
122 (princ " doc: " (current-buffer))
123 (if (string-match "\n" doc)
124 (setq doc (concat (substring doc 0 (match-beginning 0))
129 (prin1 args (current-buffer))
131 (let ((interactive (cond ((consp obj)
132 (assq 'interactive obj))
134 (list 'interactive (aref obj 5))))))
137 (setq interactive (nth 1 interactive))
138 (if (eq (car-safe (car-safe obj)) 'interactive)
139 (setq obj (cdr obj)))
141 (insert " interactive: ")
142 (if (eq (car-safe interactive) 'byte-code)
145 (disassemble-1 interactive
146 (+ indent disassemble-recursive-indent)))
147 (let ((print-escape-newlines t))
148 (prin1 interactive (current-buffer))))
150 (cond ((and (consp obj) (assq 'byte-code obj))
151 (disassemble-1 (assq 'byte-code obj) indent))
152 ((byte-code-function-p obj)
153 (disassemble-1 obj indent))
155 (insert "Uncompiled body: ")
156 (let ((print-escape-newlines t))
157 (prin1 (if (cdr obj) (cons 'progn obj) (car obj))
158 (current-buffer))))))
163 (defun disassemble-1 (obj indent)
164 "Prints the byte-code call OBJ in the current buffer.
165 OBJ should be a call to BYTE-CODE generated by the byte compiler."
166 (let (bytes constvec)
168 (setq bytes (car (cdr obj)) ;the byte code
169 constvec (car (cdr (cdr obj)))) ;constant vector
170 ;; If it is lazy-loaded, load it now
172 (setq bytes (aref obj 1)
173 constvec (aref obj 2)))
174 (let ((lap (byte-decompile-bytecode bytes constvec))
175 op arg opname pc-value)
179 (while (setq tmp (assq 'TAG lap))
180 (setcar (cdr tmp) (setq tagno (1+ tagno)))
181 (setq lap (cdr (memq tmp lap)))))
183 ;; Take off the pc value of the next thing
184 ;; and put it in pc-value.
186 (if (numberp (car lap))
187 (setq pc-value (car lap)
189 ;; Fetch the next op and its arg.
190 (setq op (car (car lap))
196 ;; We have a label. Display it, but first its pc value.
198 (insert (format "%d:" pc-value)))
199 (insert (int-to-string (car arg))))
200 ;; We have an instruction. Display its pc value first.
202 (insert (format "%d" pc-value)))
203 (indent-to (+ indent disassemble-column-1-indent))
205 (string-match "^byte-" (setq opname (symbol-name op))))
206 (setq opname (substring opname 5))
207 (setq opname "<not-an-opcode>"))
208 (if (eq op 'byte-constant2)
209 (insert " #### shouldn't have seen constant2 here!\n "))
211 (indent-to (+ indent disassemble-column-1-indent
212 disassemble-column-2-indent
215 (cond ((memq op byte-goto-ops)
216 (insert (int-to-string (nth 1 arg))))
217 ((memq op '(byte-call byte-unbind
218 byte-listN byte-concatN byte-insertN))
219 (insert (int-to-string arg)))
220 ((memq op '(byte-varref byte-varset byte-varbind))
221 (prin1 (car arg) (current-buffer)))
222 ((memq op '(byte-constant byte-constant2))
225 ;; but if the value of the constant is compiled code, then
226 ;; recursively disassemble it.
227 (cond ((or (byte-code-function-p arg)
228 (and (eq (car-safe arg) 'lambda)
229 (assq 'byte-code arg))
230 (and (eq (car-safe arg) 'macro)
231 (or (byte-code-function-p (cdr arg))
232 (and (eq (car-safe (cdr arg)) 'lambda)
233 (assq 'byte-code (cdr arg))))))
234 (cond ((byte-code-function-p arg)
235 (insert "<compiled-function>\n"))
236 ((eq (car-safe arg) 'lambda)
237 (insert "<compiled lambda>"))
238 (t (insert "<compiled macro>\n")))
239 (disassemble-internal
241 (+ indent disassemble-recursive-indent 1)
243 ((eq (car-safe arg) 'byte-code)
244 (insert "<byte code>\n")
245 (disassemble-1 ;recurse on byte-code object
247 (+ indent disassemble-recursive-indent)))
248 ((eq (car-safe (car-safe arg)) 'byte-code)
249 (insert "(<byte code>...)\n")
250 (mapcar ;recurse on list of byte-code objects
254 (+ indent disassemble-recursive-indent)))
257 ;; really just a constant
258 (let ((print-escape-newlines t))
259 (prin1 arg (current-buffer))))))
264 ;;; disass.el ends here