lisp/emacs-lisp/find-gc.el

   1 ;;; find-gc.el --- detect functions that call the garbage collector
   2
   3 ;; Copyright (C) 1992, 2001-2014 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 3 of the License, or
  12 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  21
  22 ;;; Commentary:
  23
  24 ;; Produce in find-gc-unsafe-list the set of all functions that may invoke GC.
  25 ;; This expects the Emacs sources to live in find-gc-source-directory.
  26 ;; It creates a temporary working directory /tmp/esrc.
  27
  28 ;;; Code:
  29
  30 (defvar find-gc-unsafe-list nil
  31   "The list of unsafe functions is placed here by `find-gc-unsafe'.")
  32
  33 (defvar find-gc-source-directory)
  34
  35 (defvar find-gc-subrs-callers nil
  36   "Alist of users of subrs, from GC testing.
  37 Each entry has the form (FUNCTION . FUNCTIONS-THAT-CALL-IT).")
  38
  39 (defvar find-gc-subrs-called nil
  40   "Alist of subrs called, in GC testing.
  41 Each entry has the form (FUNCTION . FUNCTIONS-IT-CALLS).")
  42
  43
  44 ;;; Functions on this list are safe, even if they appear to be able
  45 ;;; to call the target.
  46
  47 (defvar find-gc-noreturn-list '(Fsignal Fthrow wrong_type_argument))
  48
  49 ;;; This was originally generated directory-files, but there were
  50 ;;; too many files there that were not actually compiled.  The
  51 ;;; list below was created for a HP-UX 7.0 system.
  52
  53 (defvar find-gc-source-files
  54   '("dispnew.c" "scroll.c" "xdisp.c" "window.c"
  55     "term.c" "cm.c" "emacs.c" "keyboard.c" "macros.c"
  56     "keymap.c" "sysdep.c" "buffer.c" "filelock.c"
  57     "insdel.c" "marker.c" "minibuf.c" "fileio.c"
  58     "dired.c" "cmds.c" "casefiddle.c"
  59     "indent.c" "search.c" "regex.c" "undo.c"
  60     "alloc.c" "data.c" "doc.c" "editfns.c"
  61     "callint.c" "eval.c" "fns.c" "print.c" "lread.c"
  62     "abbrev.c" "syntax.c" "unexcoff.c"
  63     "bytecode.c" "process.c" "callproc.c" "doprnt.c"
  64     "x11term.c" "x11fns.c"))
  65
  66
  67 (defun find-gc-unsafe ()
  68   "Return a list of unsafe functions--that is, which can call GC.
  69 Also store it in `find-gc-unsafe'."
  70   (trace-call-tree nil)
  71   (trace-use-tree)
  72   (find-unsafe-funcs 'Fgarbage_collect)
  73   (setq find-gc-unsafe-list
  74         (sort find-gc-unsafe-list
  75               (function (lambda (x y)
  76                           (string-lessp (car x) (car y))))))
  77 )
  78
  79 ;;; This does a depth-first search to find all functions that can
  80 ;;; ultimately call the function "target".  The result is an a-list
  81 ;;; in find-gc-unsafe-list; the cars are the unsafe functions, and the cdrs
  82 ;;; are (one of) the unsafe functions that these functions directly
  83 ;;; call.
  84
  85 (defun find-unsafe-funcs (target)
  86   (setq find-gc-unsafe-list (list (list target)))
  87   (trace-unsafe target)
  88 )
  89
  90 (defun trace-unsafe (func)
  91   (let ((used (assq func find-gc-subrs-callers)))
  92     (or used
  93         (error "No find-gc-subrs-callers for %s" (car find-gc-unsafe-list)))
  94     (while (setq used (cdr used))
  95       (or (assq (car used) find-gc-unsafe-list)
  96           (memq (car used) find-gc-noreturn-list)
  97           (progn
  98             (push (cons (car used) func) find-gc-unsafe-list)
  99             (trace-unsafe (car used))))))
 100 )
 101
 102
 103
 104
 105 (defun trace-call-tree (&optional already-setup)
 106   (message "Setting up directories...")
 107   (or already-setup
 108       (progn
 109         ;; Gee, wouldn't a built-in "system" function be handy here.
 110         (call-process "csh" nil nil nil "-c" "rm -rf /tmp/esrc")
 111         (call-process "csh" nil nil nil "-c" "mkdir /tmp/esrc")
 112         (call-process "csh" nil nil nil "-c"
 113                       (format "ln -s %s/*.[ch] /tmp/esrc"
 114                               find-gc-source-directory))))
 115   (with-current-buffer (get-buffer-create "*Trace Call Tree*")
 116     (setq find-gc-subrs-called nil)
 117     (let ((case-fold-search nil)
 118           (files find-gc-source-files)
 119           name entry)
 120       (while files
 121         (message "Compiling %s..." (car files))
 122         (call-process "csh" nil nil nil "-c"
 123                       (format "gcc -dr -c /tmp/esrc/%s -o /dev/null"
 124                               (car files)))
 125         (erase-buffer)
 126         (insert-file-contents (concat "/tmp/esrc/" (car files) ".rtl"))
 127         (while (re-search-forward ";; Function \\|(call_insn " nil t)
 128           (if (= (char-after (- (point) 3)) ?o)
 129               (progn
 130                 (looking-at "[a-zA-Z0-9_]+")
 131                 (setq name (intern (buffer-substring (match-beginning 0)
 132                                                      (match-end 0))))
 133                 (message "%s : %s" (car files) name)
 134                 (setq entry (list name)
 135                       find-gc-subrs-called (cons entry find-gc-subrs-called)))
 136             (if (looking-at ".*\n?.*\"\\([A-Za-z0-9_]+\\)\"")
 137                 (progn
 138                   (setq name (intern (buffer-substring (match-beginning 1)
 139                                                        (match-end 1))))
 140                   (or (memq name (cdr entry))
 141                       (setcdr entry (cons name (cdr entry))))))))
 142         (delete-file (concat "/tmp/esrc/" (car files) ".rtl"))
 143         (setq files (cdr files)))))
 144 )
 145
 146
 147 (defun trace-use-tree ()
 148   (setq find-gc-subrs-callers (mapcar 'list (mapcar 'car find-gc-subrs-called)))
 149   (let ((ptr find-gc-subrs-called)
 150         p2 found)
 151     (while ptr
 152       (setq p2 (car ptr))
 153       (while (setq p2 (cdr p2))
 154         (if (setq found (assq (car p2) find-gc-subrs-callers))
 155             (setcdr found (cons (car (car ptr)) (cdr found)))))
 156       (setq ptr (cdr ptr))))
 157 )
 158
 159 (provide 'find-gc)
 160
 161 ;;; find-gc.el ends here