gcc/analyzer/sm-file.dot

   1 /* An overview of the state machine from sm-file.cc.
   2    Copyright (C) 2022-2023 Free Software Foundation, Inc.
   3    Contributed by David Malcolm <dmalcolm@redhat.com>.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it
   8 under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful, but
  13 WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 /* Keep this in-sync with sm-file.cc  */
  22
  23 digraph "file" {
  24
  25   /* STATES. */
  26
  27   /* Start state.  */
  28   start;
  29
  30   /* State for a FILE * returned from fopen that hasn't been checked for
  31      NULL.
  32      It could be an open stream, or could be NULL.  */
  33   unchecked;
  34
  35   /* State for a FILE * that's known to be NULL.  */
  36   null;
  37
  38   /* State for a FILE * that's known to be a non-NULL open stream.  */
  39   nonnull;
  40
  41   /* State for a FILE * that's had fclose called on it.  */
  42   closed;
  43
  44   /* Stop state, for a FILE * we don't want to track any more.  */
  45   stop;
  46
  47   /* TRANSITIONS. */
  48
  49   /* On "fopen".  */
  50   start -> unchecked [label="on 'X = fopen(...);'"];
  51
  52   /* On "fclose".  */
  53   start -> closed [label="on 'close(X);'"];
  54   /* TODO: is it safe to call fclose (NULL) ? */
  55   unchecked -> closed [label="on 'close(X);'"];
  56   null -> closed [label="on 'close(X);'"];
  57   nonnull -> closed [label="on 'close(X);'"];
  58   closed -> stop [label="on 'close(X);':\nWarn('double fclose')"];
  59
  60   /* on_condition.  */
  61   unchecked -> nonnull [label="on 'X != 0'"];
  62   unchecked -> null [label="on 'X == 0'"];
  63
  64   /* Leaks.  */
  65   unchecked -> stop [label="on leak:\nWarn('leak')"];
  66   nonnull -> stop [label="on leak:\nWarn('leak')"];
  67 }