domwalk.h revision 169690 
1/* Generic dominator tree walker
2   Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
3   Contributed by Diego Novillo <dnovillo@redhat.com>
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify
8it under the terms of the GNU General Public License as published by
9the Free Software Foundation; either version 2, or (at your option)
10any later version.
11
12GCC is distributed in the hope that it will be useful,
13but WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15GNU General Public License for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING.  If not, write to
19the Free Software Foundation, 51 Franklin Street, Fifth Floor,
20Boston, MA 02110-1301, USA.  */
21
22typedef void *void_p;
23DEF_VEC_P(void_p);
24DEF_VEC_ALLOC_P(void_p,heap);
25
26/* This is the main data structure for the dominator walker.  It provides
27   the callback hooks as well as a convenient place to hang block local
28   data and pass-global data.  */
29
30struct dom_walk_data
31{
32  /* This is the direction of the dominator tree we want to walk.  i.e.,
33     if it is set to CDI_DOMINATORS, then we walk the dominator tree,
34     if it is set to CDI_POST_DOMINATORS, then we walk the post
35     dominator tree.  */
36  ENUM_BITFIELD (cdi_direction) dom_direction : 2;
37
38  /* Nonzero if the statement walker should walk the statements from
39     last to first within a basic block instead of first to last.
40
41     Note this affects both statement walkers.  We haven't yet needed
42     to use the second statement walker for anything, so it's hard to
43     predict if we really need the ability to select their direction
44     independently.  */
45  BOOL_BITFIELD walk_stmts_backward : 1;
46
47  /* Function to initialize block local data.
48
49     Note that the dominator walker infrastructure may provide a new
50     fresh, and zero'd block local data structure, or it may re-use an
51     existing block local data structure.
52
53     If the block local structure has items such as virtual arrays, then
54     that allows your optimizer to re-use those arrays rather than
55     creating new ones.  */
56  void (*initialize_block_local_data) (struct dom_walk_data *,
57				       basic_block, bool);
58
59  /* Function to call before the statement walk occurring before the
60     recursive walk of the dominator children.
61
62     This typically initializes a block local data and pushes that
63     data onto BLOCK_DATA_STACK.  */
64  void (*before_dom_children_before_stmts) (struct dom_walk_data *,
65					    basic_block);
66
67  /* Function to call to walk statements before the recursive walk
68     of the dominator children.  */
69  void (*before_dom_children_walk_stmts) (struct dom_walk_data *,
70					  basic_block, block_stmt_iterator);
71
72  /* Function to call after the statement walk occurring before the
73     recursive walk of the dominator children.  */
74  void (*before_dom_children_after_stmts) (struct dom_walk_data *,
75					   basic_block);
76
77  /* Function to call before the statement walk occurring after the
78     recursive walk of the dominator children.  */
79  void (*after_dom_children_before_stmts) (struct dom_walk_data *,
80					   basic_block);
81
82  /* Function to call to walk statements after the recursive walk
83     of the dominator children.  */
84  void (*after_dom_children_walk_stmts) (struct dom_walk_data *,
85					 basic_block, block_stmt_iterator);
86
87  /* Function to call after the statement walk occurring after the
88     recursive walk of the dominator children.
89
90     This typically finalizes any block local data and pops
91     that data from BLOCK_DATA_STACK.  */
92  void (*after_dom_children_after_stmts) (struct dom_walk_data *,
93					  basic_block);
94
95  /* Global data for a walk through the dominator tree.  */
96  void *global_data;
97
98  /* Stack of any data we need to keep on a per-block basis.
99
100     If you have no local data, then BLOCK_DATA_STACK will be NULL.  */
101  VEC(void_p,heap) *block_data_stack;
102
103  /* Size of the block local data.   If this is zero, then it is assumed
104     you have no local data and thus no BLOCK_DATA_STACK as well.  */
105  size_t block_local_data_size;
106
107  /* From here below are private data.  Please do not use this
108     information/data outside domwalk.c.  */
109
110  /* Stack of available block local structures.  */
111  VEC(void_p,heap) *free_block_data;
112
113  /* Interesting blocks to process.  If this field is not NULL, this
114     set is used to determine which blocks to walk.  If we encounter
115     block I in the dominator traversal, but block I is not present in
116     INTERESTING_BLOCKS, then none of the callback functions are
117     invoked on it.  This is useful when a particular traversal wants
118     to filter out non-interesting blocks from the dominator tree.  */
119  sbitmap interesting_blocks;
120};
121
122void walk_dominator_tree (struct dom_walk_data *, basic_block);
123void init_walk_dominator_tree (struct dom_walk_data *);
124void fini_walk_dominator_tree (struct dom_walk_data *);
125