gcc/domwalk.h

   1 /* Generic dominator tree walker
   2    Copyright (C) 2003, 2004 Free Software Foundation, Inc.
   3    Contributed by Diego Novillo <dnovillo@redhat.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU 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 COPYING.  If not, write to
  19 the Free Software Foundation, 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22 /* This is the main data structure for the dominator walker.  It provides
  23    the callback hooks as well as a convenient place to hang block local
  24    data and pass-global data.  */
  25
  26 struct dom_walk_data
  27 {
  28   /* This is the direction of the dominator tree we want to walk.  ie,
  29      if it is set to CDI_DOMINATORS, then we walk the dominator tree,
  30      if it is set to CDI_POST_DOMINATORS, then we walk the post
  31      dominator tree.  */
  32   ENUM_BITFIELD (cdi_direction) dom_direction : 2;
  33
  34   /* Nonzero if the statement walker should walk the statements from
  35      last to first within a basic block instead of first to last.
  36
  37      Note this affects both statement walkers.  We haven't yet needed
  38      to use the second statement walker for anything, so it's hard to
  39      predict if we really need the ability to select their direction
  40      independently.  */
  41   BOOL_BITFIELD walk_stmts_backward : 1;
  42
  43   /* Function to initialize block local data.
  44
  45      Note that the dominator walker infrastructure may provide a new
  46      fresh, and zero'd block local data structure, or it may re-use an
  47      existing block local data structure.
  48
  49      If the block local structure has items such as virtual arrays, then
  50      that allows your optimizer to re-use those arrays rather than
  51      creating new ones.  */
  52   void (*initialize_block_local_data) (struct dom_walk_data *,
  53                                        basic_block, bool);
  54
  55   /* Function to call before the statement walk occurring before the
  56      recursive walk of the dominator children.
  57
  58      This typically initializes an block local data and pushes that
  59      data onto BLOCK_DATA_STACK.  */
  60   void (*before_dom_children_before_stmts) (struct dom_walk_data *,
  61                                             basic_block);
  62
  63   /* Function to call to walk statements before the recursive walk
  64      of the dominator children.  */
  65   void (*before_dom_children_walk_stmts) (struct dom_walk_data *,
  66                                           basic_block, block_stmt_iterator);
  67
  68   /* Function to call after the statement walk occurring before the
  69      recursive walk of the dominator children.  */
  70   void (*before_dom_children_after_stmts) (struct dom_walk_data *,
  71                                            basic_block);
  72
  73   /* Function to call before the statement walk occurring after the
  74      recursive walk of the dominator children.  */
  75   void (*after_dom_children_before_stmts) (struct dom_walk_data *,
  76                                            basic_block);
  77
  78   /* Function to call to walk statements after the recursive walk
  79      of the dominator children.  */
  80   void (*after_dom_children_walk_stmts) (struct dom_walk_data *,
  81                                          basic_block, block_stmt_iterator);
  82
  83   /* Function to call after the statement walk occurring after the
  84      recursive walk of the dominator children.
  85
  86      This typically finalizes any block local data and pops
  87      that data from BLOCK_DATA_STACK.  */
  88   void (*after_dom_children_after_stmts) (struct dom_walk_data *,
  89                                           basic_block);
  90
  91   /* Global data for a walk through the dominator tree.  */
  92   void *global_data;
  93
  94   /* Stack of any data we need to keep on a per-block basis.
  95
  96      If you have no local data, then BLOCK_DATA_STACK will be NULL.  */
  97   varray_type block_data_stack;
  98
  99   /* Size of the block local data.   If this is zero, then it is assumed
 100      you have no local data and thus no BLOCK_DATA_STACK as well.  */
 101   size_t block_local_data_size;
 102
 103   /* From here below are private data.  Please do not use this
 104      information/data outside domwalk.c.  */
 105
 106   /* Stack of available block local structures.   */
 107   varray_type free_block_data;
 108 };
 109
 110 void walk_dominator_tree (struct dom_walk_data *, basic_block);
 111 void init_walk_dominator_tree (struct dom_walk_data *);
 112 void fini_walk_dominator_tree (struct dom_walk_data *);