binutils/dwarf-mode.el

   1 ;;; dwarf-mode.el --- Browser for DWARF information. -*-lexical-binding:t-*-
   2
   3 ;; Version: 1.5
   4
   5 ;; Copyright (C) 2012-2020 Free Software Foundation, Inc.
   6
   7 ;; This file is not part of GNU Emacs, but is distributed under the
   8 ;; same terms:
   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 ;;; Code:
  24
  25 (defvar dwarf-objdump-program "objdump")
  26
  27 (defconst dwarf-font-lock-keywords
  28   '(
  29     ;; Name and linkage name.
  30     ("DW_AT_[a-z_]*name\\s *: .*:\\(.*\\)\\s *$"
  31      (1 font-lock-function-name-face))
  32
  33     ("Compilation Unit @ offset 0x[0-9a-f]+"
  34      (0 font-lock-string-face))
  35     ))
  36
  37 (defvar dwarf-file nil
  38   "Buffer-local variable holding the file name passed to objdump.")
  39
  40 (defvar dwarf--process nil
  41   "Running objdump process, or nil.")
  42
  43 (defvar dwarf--deletion-region nil
  44   "Region to delete before inserting text in `dwarf--filter'.")
  45
  46 (defun dwarf--check-running ()
  47   "Throw an exception if an objdump process is already running."
  48   (when dwarf--process
  49     (error "An objdump process is still running in this buffer")))
  50
  51 (defun dwarf--filter (proc string)
  52   "Filter function for objdump processes."
  53   (when (buffer-live-p (process-buffer proc))
  54     (with-current-buffer (process-buffer proc)
  55       (save-excursion
  56         (let ((inhibit-read-only t))
  57           (when dwarf--deletion-region
  58             (apply #'delete-region dwarf--deletion-region)
  59             (setq dwarf--deletion-region nil))
  60           (goto-char (process-mark proc))
  61           (insert string)
  62           (set-marker (process-mark proc) (point))
  63           (set-buffer-modified-p nil))))))
  64
  65 (defun dwarf--sentinel (_proc _status)
  66   (setq mode-line-process nil)
  67   (setq dwarf--process nil))
  68
  69 (defun dwarf--invoke (start end &rest command)
  70   "Invoke a command and arrange to insert output into the current buffer."
  71   (setq mode-line-process "[Running]")
  72   (setq dwarf--deletion-region (list start end))
  73   (setq dwarf--process (make-process :name "objdump"
  74                                      :buffer (current-buffer)
  75                                      :command command
  76                                      :connection-type 'pipe
  77                                      :noquery t
  78                                      :filter #'dwarf--filter
  79                                      :sentinel #'dwarf--sentinel))
  80   (set-marker (process-mark dwarf--process) (point)))
  81
  82 ;; Expand a "..." to show all the child DIES.  NEW-DEPTH controls how
  83 ;; deep to display the new dies; `nil' means display all of them.
  84 (defun dwarf-do-insert-substructure (new-depth die)
  85   (dwarf--check-running)
  86   (let ((inhibit-read-only t))
  87     (beginning-of-line)
  88     (apply #'dwarf--invoke
  89            (point) (save-excursion
  90                      (end-of-line)
  91                      (forward-char)
  92                      (point))
  93            dwarf-objdump-program "-Wi" (concat "--dwarf-start=0x" die)
  94            (expand-file-name dwarf-file)
  95            (if new-depth (list (concat "--dwarf-depth="
  96                                        (int-to-string new-depth)))))
  97     (set-buffer-modified-p nil)))
  98
  99 (defun dwarf-insert-substructure-button (die)
 100   (beginning-of-line)
 101   (unless (looking-at "^ <\\([0-9]+\\)>")
 102     (error "Unrecognized line."))
 103   (let ((new-depth (1+ (string-to-number (match-string 1)))))
 104     (dwarf-do-insert-substructure new-depth die)))
 105
 106 (defun dwarf-insert-substructure (arg)
 107   "Expand a `...' to show children of the current DIE.
 108 By default, expands just one level of children.
 109 A prefix argument means expand all children."
 110   (interactive "P")
 111   (beginning-of-line)
 112   (unless (looking-at "^ <\\([0-9]+\\)><\\([0-9a-f]+\\)>")
 113     (error "Unrecognized line."))
 114   (let ((die (match-string 2)))
 115     (if arg
 116         (dwarf-do-insert-substructure nil die)
 117       (dwarf-insert-substructure-button die))))
 118
 119 ;; Called when a button is pressed.
 120 ;; Either follows a DIE reference, or expands a "...".
 121 (defun dwarf-die-button-action (button)
 122   (let* ((die (button-get button 'die))
 123          ;; Note that the first number can only be decimal.
 124          (die-rx (concat "^\\s *\\(<[0-9]+>\\)?<"
 125                          die ">[^<]"))
 126          (old (point))
 127          (is-ref (button-get button 'die-ref)))
 128     (if is-ref
 129         (progn
 130           (goto-char (point-min))
 131           (if (re-search-forward die-rx nil 'move)
 132               (push-mark old)
 133             (goto-char old)
 134             (error "Could not find DIE <0x%s>" die)))
 135       (dwarf-insert-substructure-button die))))
 136
 137 ;; Button definition.
 138 (define-button-type 'dwarf-die-button
 139   'follow-link t
 140   'action #'dwarf-die-button-action)
 141
 142 ;; Helper regexp to match a DIE reference.
 143 (defconst dwarf-die-reference "\\(<0x\\([0-9a-f]+\\)>\\)")
 144
 145 ;; Helper regexp to match a `...' indicating that there are hidden
 146 ;; children.
 147 (defconst dwarf-die-more "^ <[0-9]+><\\([0-9a-z]+\\)>: \\([.][.][.]\\)")
 148
 149 ;; jit-lock callback function to fontify a region.  This applies the
 150 ;; buttons, since AFAICT there is no good way to apply buttons via
 151 ;; font-lock.
 152 (defun dwarf-fontify-region (start end)
 153   (save-excursion
 154     (let ((beg-line (progn (goto-char start) (line-beginning-position)))
 155           (end-line (progn (goto-char end) (line-end-position))))
 156       (goto-char beg-line)
 157       (while (re-search-forward dwarf-die-reference end-line 'move)
 158         (let ((b-start (match-beginning 1))
 159               (b-end (match-end 1))
 160               (hex (match-string-no-properties 2)))
 161           (make-text-button b-start b-end :type 'dwarf-die-button
 162                             'die hex 'die-ref t)))
 163       ;; This is a bogus approach.  Why can't we make buttons from the
 164       ;; font-lock defaults?
 165       (goto-char beg-line)
 166       (while (re-search-forward dwarf-die-more end-line 'move)
 167         (let ((hex (match-string-no-properties 1))
 168               (b-start (match-beginning 2))
 169               (b-end (match-end 2)))
 170           (make-text-button b-start b-end :type 'dwarf-die-button
 171                             'die hex 'die-ref nil))))))
 172
 173 ;; Run objdump and insert the contents into the buffer.  The arguments
 174 ;; are the way they are because this is also called as a
 175 ;; revert-buffer-function.
 176 (defun dwarf-do-refresh (&rest ignore)
 177   (dwarf--check-running)
 178   (let ((inhibit-read-only t))
 179     (dwarf--invoke (point-min) (point-max)
 180                    dwarf-objdump-program "-Wi" "--dwarf-depth=1"
 181                    (expand-file-name dwarf-file))
 182     (set-buffer-modified-p nil)))
 183
 184 (defvar dwarf-mode-syntax-table
 185   (let ((table (make-syntax-table)))
 186     ;; This at least makes it so mark-sexp on some hex digits inside
 187     ;; <...> does not also copy the ">".
 188     (modify-syntax-entry ?< "(>" table)
 189     (modify-syntax-entry ?> ")<" table)
 190     table)
 191   "Syntax table for dwarf-mode buffers.")
 192
 193 (defvar dwarf-mode-map
 194   (let ((map (make-sparse-keymap)))
 195     (set-keymap-parent map special-mode-map)
 196     (define-key map [(control ?m)] #'dwarf-insert-substructure)
 197     map)
 198   "Keymap for dwarf-mode buffers.")
 199
 200 (define-derived-mode dwarf-mode special-mode "DWARF"
 201   "Major mode for browsing DWARF output.
 202
 203 \\{dwarf-mode-map}"
 204
 205   (set (make-local-variable 'font-lock-defaults) '(dwarf-font-lock-keywords))
 206   ;; FIXME: we could be smarter and check the file time.
 207   (set (make-local-variable 'revert-buffer-function) #'dwarf-do-refresh)
 208   (jit-lock-register #'dwarf-fontify-region))
 209
 210 ;;;###autoload
 211 (defun dwarf-browse (file)
 212   "Invoke `objdump' and put output into a `dwarf-mode' buffer.
 213 This is the main interface to `dwarf-mode'."
 214   (interactive "fFile name: ")
 215   (let* ((base-name (file-name-nondirectory file))
 216          (buffer (generate-new-buffer (concat "*DWARF for " base-name "*"))))
 217     (pop-to-buffer buffer)
 218     (dwarf-mode)
 219     (setq default-directory (file-name-directory file))
 220     (set (make-local-variable 'dwarf-file) file)
 221     (set (make-local-variable 'dwarf--process) nil)
 222     (set (make-local-variable 'dwarf--deletion-region) nil)
 223     (dwarf-do-refresh)))
 224
 225 (provide 'dwarf-mode)
 226
 227 ;;; dwarf-mode.el ends here