lisp/emacs-lisp/find-gc.el

   1 ;;; find-gc.el --- detect functions that call the garbage collector
   2
   3 ;; Copyright (C) 1992 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: FSF
   6
   7 ;; This file is part of GNU Emacs.
   8
   9 ;; GNU Emacs is free software; you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation; either version 2, or (at your option)
  12 ;; any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  21 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  22 ;; Boston, MA 02110-1301, USA.
  23
  24 ;;; Commentary:
  25
  26 ;; Produce in find-gc-unsafe-list the set of all functions that may invoke GC.
  27 ;; This expects the Emacs sources to live in find-gc-source-directory.
  28 ;; It creates a temporary working directory /tmp/esrc.
  29
  30 ;;; Code:
  31
  32 (defvar find-gc-unsafe-list nil
  33   "The list of unsafe functions is placed here by `find-gc-unsafe'.")
  34
  35 (defvar find-gc-source-directory)
  36
  37 (defvar find-gc-subrs-used nil
  38   "List of subrs used so far in GC testing.")
  39
  40 ;;; Functions on this list are safe, even if they appear to be able
  41 ;;; to call the target.
  42
  43 (defvar find-gc-noreturn-list '(Fsignal Fthrow wrong_type_argument))
  44
  45 ;;; This was originally generated directory-files, but there were
  46 ;;; too many files there that were not actually compiled.  The
  47 ;;; list below was created for a HP-UX 7.0 system.
  48
  49 (defvar find-gc-source-files
  50   '("dispnew.c" "scroll.c" "xdisp.c" "window.c"
  51     "term.c" "cm.c" "emacs.c" "keyboard.c" "macros.c"
  52     "keymap.c" "sysdep.c" "buffer.c" "filelock.c"
  53     "insdel.c" "marker.c" "minibuf.c" "fileio.c"
  54     "dired.c" "filemode.c" "cmds.c" "casefiddle.c"
  55     "indent.c" "search.c" "regex.c" "undo.c"
  56     "alloc.c" "data.c" "doc.c" "editfns.c"
  57     "callint.c" "eval.c" "fns.c" "print.c" "lread.c"
  58     "abbrev.c" "syntax.c" "unexec.c"
  59     "bytecode.c" "process.c" "callproc.c" "doprnt.c"
  60     "x11term.c" "x11fns.c"))
  61
  62
  63 (defun find-gc-unsafe ()
  64   "Return a list of unsafe functions--that is, which can call GC.
  65 Also store it in `find-gc-unsafe'."
  66   (trace-call-tree nil)
  67   (trace-use-tree)
  68   (find-unsafe-funcs 'Fgarbage_collect)
  69   (setq find-gc-unsafe-list
  70         (sort find-gc-unsafe-list
  71               (function (lambda (x y)
  72                           (string-lessp (car x) (car y))))))
  73 )
  74
  75 ;;; This does a depth-first search to find all functions that can
  76 ;;; ultimately call the function "target".  The result is an a-list
  77 ;;; in find-gc-unsafe-list; the cars are the unsafe functions, and the cdrs
  78 ;;; are (one of) the unsafe functions that these functions directly
  79 ;;; call.
  80
  81 (defun find-unsafe-funcs (target)
  82   (setq find-gc-unsafe-list (list (list target)))
  83   (trace-unsafe target)
  84 )
  85
  86 (defun trace-unsafe (func)
  87   (let ((used (assq func find-gc-subrs-used)))
  88     (or used
  89         (error "No find-gc-subrs-used for %s" (car find-gc-unsafe-list)))
  90     (while (setq used (cdr used))
  91       (or (assq (car used) find-gc-unsafe-list)
  92           (memq (car used) find-gc-noreturn-list)
  93           (progn
  94             (push (cons (car used) func) find-gc-unsafe-list)
  95             (trace-unsafe (car used))))))
  96 )
  97
  98
  99
 100 ;;; This produces an a-list of functions in subrs-called.  The cdr of
 101 ;;; each entry is a list of functions which the function in car calls.
 102
 103 (defun trace-call-tree (&optional already-setup)
 104   (message "Setting up directories...")
 105   (or already-setup
 106       (progn
 107         ;; Gee, wouldn't a built-in "system" function be handy here.
 108         (call-process "csh" nil nil nil "-c" "rm -rf /tmp/esrc")
 109         (call-process "csh" nil nil nil "-c" "mkdir /tmp/esrc")
 110         (call-process "csh" nil nil nil "-c"
 111                       (format "ln -s %s/*.[ch] /tmp/esrc"
 112                               find-gc-source-directory))))
 113   (save-excursion
 114     (set-buffer (get-buffer-create "*Trace Call Tree*"))
 115     (setq subrs-called nil)
 116     (let ((case-fold-search nil)
 117           (files find-gc-source-files)
 118           name entry)
 119       (while files
 120         (message "Compiling %s..." (car files))
 121         (call-process "csh" nil nil nil "-c"
 122                       (format "gcc -dr -c /tmp/esrc/%s -o /dev/null"
 123                               (car files)))
 124         (erase-buffer)
 125         (insert-file-contents (concat "/tmp/esrc/" (car files) ".rtl"))
 126         (while (re-search-forward ";; Function \\|(call_insn " nil t)
 127           (if (= (char-after (- (point) 3)) ?o)
 128               (progn
 129                 (looking-at "[a-zA-Z0-9_]+")
 130                 (setq name (intern (buffer-substring (match-beginning 0)
 131                                                      (match-end 0))))
 132                 (message "%s : %s" (car files) name)
 133                 (setq entry (list name)
 134                       subrs-called (cons entry subrs-called)))
 135             (if (looking-at ".*\n?.*\"\\([A-Za-z0-9_]+\\)\"")
 136                 (progn
 137                   (setq name (intern (buffer-substring (match-beginning 1)
 138                                                        (match-end 1))))
 139                   (or (memq name (cdr entry))
 140                       (setcdr entry (cons name (cdr entry))))))))
 141         (delete-file (concat "/tmp/esrc/" (car files) ".rtl"))
 142         (setq files (cdr files)))))
 143 )
 144
 145
 146 ;;; This produces an inverted a-list in find-gc-subrs-used.  The cdr of each
 147 ;;; entry is a list of functions that call the function in car.
 148
 149 (defun trace-use-tree ()
 150   (setq find-gc-subrs-used (mapcar 'list (mapcar 'car subrs-called)))
 151   (let ((ptr subrs-called)
 152         p2 found)
 153     (while ptr
 154       (setq p2 (car ptr))
 155       (while (setq p2 (cdr p2))
 156         (if (setq found (assq (car p2) find-gc-subrs-used))
 157             (setcdr found (cons (car (car ptr)) (cdr found)))))
 158       (setq ptr (cdr ptr))))
 159 )
 160
 161 (provide 'find-gc)
 162
 163 ;;; arch-tag: 4a26a538-a008-40d9-a1ef-23bb6dbecef4
 164 ;;; find-gc.el ends here