binutils/dwarf-mode.el

   1 ;;; dwarf-mode.el --- Browser for DWARF information. -*-lexical-binding:t-*-
   2
   3 ;; Version: 1.6
   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-zA-Z_]*name\\s *:\\(?:\\s *(.*):\\)?\\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.  It is
 124          ;; included in this search because otherwise following a ref
 125          ;; might lead to a zero-length boolean attribute in the
 126          ;; previous DIE.
 127          (die-rx (concat "^\\s *<[0-9]+><" die ">:"))
 128          (old (point))
 129          (is-ref (button-get button 'die-ref)))
 130     (if is-ref
 131         (progn
 132           (goto-char (point-min))
 133           (if (re-search-forward die-rx nil 'move)
 134               (push-mark old)
 135             (goto-char old)
 136             (error "Could not find DIE <0x%s>" die)))
 137       (dwarf-insert-substructure-button die))))
 138
 139 ;; Button definition.
 140 (define-button-type 'dwarf-die-button
 141   'follow-link t
 142   'action #'dwarf-die-button-action)
 143
 144 ;; Helper regexp to match a DIE reference.
 145 (defconst dwarf-die-reference "\\(<0x\\([0-9a-f]+\\)>\\)")
 146
 147 ;; Helper regexp to match a `...' indicating that there are hidden
 148 ;; children.
 149 (defconst dwarf-die-more "^ <[0-9]+><\\([0-9a-z]+\\)>: \\([.][.][.]\\)")
 150
 151 ;; jit-lock callback function to fontify a region.  This applies the
 152 ;; buttons, since AFAICT there is no good way to apply buttons via
 153 ;; font-lock.
 154 (defun dwarf-fontify-region (start end)
 155   (save-excursion
 156     (let ((beg-line (progn (goto-char start) (line-beginning-position)))
 157           (end-line (progn (goto-char end) (line-end-position))))
 158       (goto-char beg-line)
 159       (while (re-search-forward dwarf-die-reference end-line 'move)
 160         (let ((b-start (match-beginning 1))
 161               (b-end (match-end 1))
 162               (hex (match-string-no-properties 2)))
 163           (make-text-button b-start b-end :type 'dwarf-die-button
 164                             'die hex 'die-ref t)))
 165       ;; This is a bogus approach.  Why can't we make buttons from the
 166       ;; font-lock defaults?
 167       (goto-char beg-line)
 168       (while (re-search-forward dwarf-die-more end-line 'move)
 169         (let ((hex (match-string-no-properties 1))
 170               (b-start (match-beginning 2))
 171               (b-end (match-end 2)))
 172           (make-text-button b-start b-end :type 'dwarf-die-button
 173                             'die hex 'die-ref nil))))))
 174
 175 ;; Run objdump and insert the contents into the buffer.  The arguments
 176 ;; are the way they are because this is also called as a
 177 ;; revert-buffer-function.
 178 (defun dwarf-do-refresh (&rest ignore)
 179   (dwarf--check-running)
 180   (let ((inhibit-read-only t))
 181     (dwarf--invoke (point-min) (point-max)
 182                    dwarf-objdump-program "-Wi" "--dwarf-depth=1"
 183                    (expand-file-name dwarf-file))
 184     (set-buffer-modified-p nil)))
 185
 186 (defvar dwarf-mode-syntax-table
 187   (let ((table (make-syntax-table)))
 188     ;; This at least makes it so mark-sexp on some hex digits inside
 189     ;; <...> does not also copy the ">".
 190     (modify-syntax-entry ?< "(>" table)
 191     (modify-syntax-entry ?> ")<" table)
 192     table)
 193   "Syntax table for dwarf-mode buffers.")
 194
 195 (defvar dwarf-mode-map
 196   (let ((map (make-sparse-keymap)))
 197     (set-keymap-parent map special-mode-map)
 198     (define-key map [(control ?m)] #'dwarf-insert-substructure)
 199     map)
 200   "Keymap for dwarf-mode buffers.")
 201
 202 (define-derived-mode dwarf-mode special-mode "DWARF"
 203   "Major mode for browsing DWARF output.
 204
 205 \\{dwarf-mode-map}"
 206
 207   (set (make-local-variable 'font-lock-defaults) '(dwarf-font-lock-keywords))
 208   ;; FIXME: we could be smarter and check the file time.
 209   (set (make-local-variable 'revert-buffer-function) #'dwarf-do-refresh)
 210   (jit-lock-register #'dwarf-fontify-region))
 211
 212 ;;;###autoload
 213 (defun dwarf-browse (file)
 214   "Invoke `objdump' and put output into a `dwarf-mode' buffer.
 215 This is the main interface to `dwarf-mode'."
 216   (interactive "fFile name: ")
 217   (let* ((base-name (file-name-nondirectory file))
 218          (buffer (generate-new-buffer (concat "*DWARF for " base-name "*"))))
 219     (pop-to-buffer buffer)
 220     (dwarf-mode)
 221     (setq default-directory (file-name-directory file))
 222     (set (make-local-variable 'dwarf-file) file)
 223     (set (make-local-variable 'dwarf--process) nil)
 224     (set (make-local-variable 'dwarf--deletion-region) nil)
 225     (dwarf-do-refresh)))
 226
 227 (provide 'dwarf-mode)
 228
 229 ;;; dwarf-mode.el ends here