lisp/emacs-lisp/find-gc.el

   1 ;;; find-gc.el --- detect functions that call the garbage collector
   2
   3 ;; Copyright (C) 1992, 2001, 2002, 2003, 2004, 2005,
   4 ;;   2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
   5
   6 ;; Maintainer: FSF
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; Produce in find-gc-unsafe-list the set of all functions that may invoke GC.
  26 ;; This expects the Emacs sources to live in find-gc-source-directory.
  27 ;; It creates a temporary working directory /tmp/esrc.
  28
  29 ;;; Code:
  30
  31 (defvar find-gc-unsafe-list nil
  32   "The list of unsafe functions is placed here by `find-gc-unsafe'.")
  33
  34 (defvar find-gc-source-directory)
  35
  36 (defvar find-gc-subrs-callers nil
  37   "Alist of users of subrs, from GC testing.
  38 Each entry has the form (FUNCTION . FUNCTIONS-THAT-CALL-IT).")
  39
  40 (defvar find-gc-subrs-called nil
  41   "Alist of subrs called, in GC testing.
  42 Each entry has the form (FUNCTION . FUNCTIONS-IT-CALLS).")
  43
  44
  45 ;;; Functions on this list are safe, even if they appear to be able
  46 ;;; to call the target.
  47
  48 (defvar find-gc-noreturn-list '(Fsignal Fthrow wrong_type_argument))
  49
  50 ;;; This was originally generated directory-files, but there were
  51 ;;; too many files there that were not actually compiled.  The
  52 ;;; list below was created for a HP-UX 7.0 system.
  53
  54 (defvar find-gc-source-files
  55   '("dispnew.c" "scroll.c" "xdisp.c" "window.c"
  56     "term.c" "cm.c" "emacs.c" "keyboard.c" "macros.c"
  57     "keymap.c" "sysdep.c" "buffer.c" "filelock.c"
  58     "insdel.c" "marker.c" "minibuf.c" "fileio.c"
  59     "dired.c" "filemode.c" "cmds.c" "casefiddle.c"
  60     "indent.c" "search.c" "regex.c" "undo.c"
  61     "alloc.c" "data.c" "doc.c" "editfns.c"
  62     "callint.c" "eval.c" "fns.c" "print.c" "lread.c"
  63     "abbrev.c" "syntax.c" "unexec.c"
  64     "bytecode.c" "process.c" "callproc.c" "doprnt.c"
  65     "x11term.c" "x11fns.c"))
  66
  67
  68 (defun find-gc-unsafe ()
  69   "Return a list of unsafe functions--that is, which can call GC.
  70 Also store it in `find-gc-unsafe'."
  71   (trace-call-tree nil)
  72   (trace-use-tree)
  73   (find-unsafe-funcs 'Fgarbage_collect)
  74   (setq find-gc-unsafe-list
  75         (sort find-gc-unsafe-list
  76               (function (lambda (x y)
  77                           (string-lessp (car x) (car y))))))
  78 )
  79
  80 ;;; This does a depth-first search to find all functions that can
  81 ;;; ultimately call the function "target".  The result is an a-list
  82 ;;; in find-gc-unsafe-list; the cars are the unsafe functions, and the cdrs
  83 ;;; are (one of) the unsafe functions that these functions directly
  84 ;;; call.
  85
  86 (defun find-unsafe-funcs (target)
  87   (setq find-gc-unsafe-list (list (list target)))
  88   (trace-unsafe target)
  89 )
  90
  91 (defun trace-unsafe (func)
  92   (let ((used (assq func find-gc-subrs-callers)))
  93     (or used
  94         (error "No find-gc-subrs-callers for %s" (car find-gc-unsafe-list)))
  95     (while (setq used (cdr used))
  96       (or (assq (car used) find-gc-unsafe-list)
  97           (memq (car used) find-gc-noreturn-list)
  98           (progn
  99             (push (cons (car used) func) find-gc-unsafe-list)
 100             (trace-unsafe (car used))))))
 101 )
 102
 103
 104
 105
 106 (defun trace-call-tree (&optional already-setup)
 107   (message "Setting up directories...")
 108   (or already-setup
 109       (progn
 110         ;; Gee, wouldn't a built-in "system" function be handy here.
 111         (call-process "csh" nil nil nil "-c" "rm -rf /tmp/esrc")
 112         (call-process "csh" nil nil nil "-c" "mkdir /tmp/esrc")
 113         (call-process "csh" nil nil nil "-c"
 114                       (format "ln -s %s/*.[ch] /tmp/esrc"
 115                               find-gc-source-directory))))
 116   (with-current-buffer (get-buffer-create "*Trace Call Tree*")
 117     (setq find-gc-subrs-called nil)
 118     (let ((case-fold-search nil)
 119           (files find-gc-source-files)
 120           name entry)
 121       (while files
 122         (message "Compiling %s..." (car files))
 123         (call-process "csh" nil nil nil "-c"
 124                       (format "gcc -dr -c /tmp/esrc/%s -o /dev/null"
 125                               (car files)))
 126         (erase-buffer)
 127         (insert-file-contents (concat "/tmp/esrc/" (car files) ".rtl"))
 128         (while (re-search-forward ";; Function \\|(call_insn " nil t)
 129           (if (= (char-after (- (point) 3)) ?o)
 130               (progn
 131                 (looking-at "[a-zA-Z0-9_]+")
 132                 (setq name (intern (buffer-substring (match-beginning 0)
 133                                                      (match-end 0))))
 134                 (message "%s : %s" (car files) name)
 135                 (setq entry (list name)
 136                       find-gc-subrs-called (cons entry find-gc-subrs-called)))
 137             (if (looking-at ".*\n?.*\"\\([A-Za-z0-9_]+\\)\"")
 138                 (progn
 139                   (setq name (intern (buffer-substring (match-beginning 1)
 140                                                        (match-end 1))))
 141                   (or (memq name (cdr entry))
 142                       (setcdr entry (cons name (cdr entry))))))))
 143         (delete-file (concat "/tmp/esrc/" (car files) ".rtl"))
 144         (setq files (cdr files)))))
 145 )
 146
 147
 148 (defun trace-use-tree ()
 149   (setq find-gc-subrs-callers (mapcar 'list (mapcar 'car find-gc-subrs-called)))
 150   (let ((ptr find-gc-subrs-called)
 151         p2 found)
 152     (while ptr
 153       (setq p2 (car ptr))
 154       (while (setq p2 (cdr p2))
 155         (if (setq found (assq (car p2) find-gc-subrs-callers))
 156             (setcdr found (cons (car (car ptr)) (cdr found)))))
 157       (setq ptr (cdr ptr))))
 158 )
 159
 160 (provide 'find-gc)
 161
 162 ;; arch-tag: 4a26a538-a008-40d9-a1ef-23bb6dbecef4
 163 ;;; find-gc.el ends here