2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Construct and access dominator tree.
23 * @author Goetz Lindenmaier
27 * This file contains routines to construct and access dominator information.
29 * The dominator information is stored in three fields of block nodes:
30 * - idom: a reference to the block that is the immediate dominator of
32 * - dom_depth: a number giving the depth of the block in the dominator
34 * - pre_num: Number in preorder traversal.
36 #ifndef FIRM_ANA_IRDOM_H
37 #define FIRM_ANA_IRDOM_H
39 #include "firm_types.h"
42 /** Accessing the dominator data structure.
44 * These routines only work properly if the ir_graph is in state
45 * dom_consistent or dom_inconsistent.
47 * If the block is not reachable from Start, returns a Bad node.
49 FIRM_API ir_node *get_Block_idom(const ir_node *bl);
50 FIRM_API void set_Block_idom(ir_node *bl, ir_node *n);
52 FIRM_API int get_Block_dom_depth(const ir_node *bl);
53 FIRM_API void set_Block_dom_depth(ir_node *bl, int depth);
55 FIRM_API int get_Block_dom_pre_num(const ir_node *bl);
56 FIRM_API void set_Block_dom_pre_num(ir_node *bl, int num);
58 /** Accessing the post dominator data structure.
60 * These routines only work properly if the ir_graph is in state
61 * dom_consistent or dom_inconsistent.
63 * If the block is not reachable from End, returns a Bad node.
65 FIRM_API ir_node *get_Block_ipostdom(const ir_node *bl);
66 FIRM_API void set_Block_ipostdom(ir_node *bl, ir_node *n);
68 FIRM_API int get_Block_postdom_depth(const ir_node *bl);
69 FIRM_API void set_Block_postdom_depth(ir_node *bl, int depth);
71 FIRM_API int get_Block_postdom_pre_num(const ir_node *bl);
72 FIRM_API void set_Block_postdom_pre_num(ir_node *bl, int num);
75 * Get the pre-order number of a block resulting from a
76 * Depth-First-Search walkover the dominator tree.
78 * @param bl The block.
79 * @return The pre-order number.
81 FIRM_API unsigned get_Block_dom_tree_pre_num(const ir_node *bl);
82 FIRM_API unsigned get_Block_pdom_tree_pre_num(const ir_node *bl);
85 * Get the largest pre-order number found in the subtree of the
86 * dominator tree rooted at a given block.
87 * @param bl The block.
88 * @return The largest pre-order number of block's dominator subtree.
90 FIRM_API unsigned get_Block_dom_max_subtree_pre_num(const ir_node *bl);
91 FIRM_API unsigned get_Block_pdom_max_subtree_pre_num(const ir_node *bl);
94 * Get the first node in the list of nodes dominated by a given block.
96 * Each node keeps a list of nodes which it immediately dominates. The
97 * nodes are queued using the @c next pointer in the @c dom_info struct.
98 * Each node keeps a head of this list using the pointer @c first in the
101 * @param bl The block for which to get the first node dominated by @c bl.
102 * @return The first node dominated by @p bl.
104 FIRM_API ir_node *get_Block_dominated_first(const ir_node *bl);
105 FIRM_API ir_node *get_Block_postdominated_first(const ir_node *bl);
108 * Get the next node in a list of nodes which are dominated by some
110 * @see get_Block_dominated_first().
111 * @param dom The previous node.
112 * @return The next node in this list or NULL if it was the last.
114 FIRM_API ir_node *get_Block_dominated_next(const ir_node *dom);
115 FIRM_API ir_node *get_Block_postdominated_next(const ir_node *dom);
118 * Iterate over all nodes which are immediately dominated by a given
120 * @param bl The block whose dominated blocks shall be iterated on.
121 * @param curr An iterator variable of type ir_node*
123 #define dominates_for_each(bl,curr) \
124 for(curr = get_Block_dominated_first(bl); curr; \
125 curr = get_Block_dominated_next(curr))
128 * Iterate over all nodes which are immediately post dominated by a given
130 * @param bl The block whose post dominated blocks shall be iterated on.
131 * @param curr An iterator variable of type ir_node*
133 #define postdominates_for_each(bl,curr) \
134 for(curr = get_Block_postdominated_first(bl); curr; \
135 curr = get_Block_postdominated_next(curr))
138 * Check, if a block dominates another block.
140 * @param a The potential dominator block.
141 * @param b The potentially dominated block.
143 * @return 1, if @p a dominates @p b, else 0.
145 FIRM_API int block_dominates(const ir_node *a, const ir_node *b);
148 * Check, if a block strictly dominates another block, i.e. a != b.
150 * @param a The potential dominator block.
151 * @param b The potentially dominated block.
153 * @return 1, if @p a strictly dominates @p b, else 0.
155 FIRM_API int block_strictly_dominates(const ir_node *a, const ir_node *b);
158 * Returns the smallest common dominator block of two nodes.
160 * @param b Another node.
161 * @return The first block dominating @p a and @p b
163 FIRM_API ir_node *node_smallest_common_dominator(ir_node *a, ir_node *b);
166 * Returns the smallest common dominator block of all users of a node
167 * BEWARE: @p irn must not be a block
168 * If on or more users are Phi nodes, one can request special handling
169 * with @p handle_phi = 1. In this case the cfg predecessor block
170 * corresponding to the position of the irn in the argument list of the
171 * Phi is determined and treated as user.
174 * @param handle_phi 1 if Phis should be handled different
175 * @return The first block dominating all users of @p irn
177 FIRM_API ir_node *node_users_smallest_common_dominator(ir_node *irn,
181 * Check, if a block post dominates another block.
183 * @param a The potential post dominator block.
184 * @param b The potentially post dominated block.
186 * @return 1, if @p a post dominates @p b, else 0.
188 FIRM_API int block_postdominates(const ir_node *a, const ir_node *b);
191 * Check, if a block strictly post dominates another block, i.e. a != b.
193 * @param a The potential post dominator block.
194 * @param b The potentially post dominated block.
196 * @return 1, if @p a strictly post dominates @p b, else 0.
198 FIRM_API int block_strictly_postdominates(const ir_node *a, const ir_node *b);
201 * Visit all nodes in the dominator subtree of a given node.
202 * Call a pre-visitor before descending to the children and call a
203 * post-visitor after returning from them.
204 * @param n The node to start walking from.
205 * @param pre The pre-visitor callback.
206 * @param post The post-visitor callback.
207 * @param env Some custom data passed to the visitors.
209 FIRM_API void dom_tree_walk(ir_node *n, irg_walk_func *pre,
210 irg_walk_func *post, void *env);
213 * Visit all nodes in the post dominator subtree of a given node.
214 * Call a pre-visitor before descending to the children and call a
215 * post-visitor after returning from them.
216 * @param n The node to start walking from.
217 * @param pre The pre-visitor callback.
218 * @param post The post-visitor callback.
219 * @param env Some custom data passed to the visitors.
221 FIRM_API void postdom_tree_walk(ir_node *n, irg_walk_func *pre,
222 irg_walk_func *post, void *env);
225 * Walk over the dominator tree of an irg starting at the root.
226 * @param irg The graph.
227 * @param pre A pre-visitor to call.
228 * @param post A post-visitor to call.
229 * @param env Some private data to give to the visitors.
231 FIRM_API void dom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
232 irg_walk_func *post, void *env);
235 * Walk over the post dominator tree of an irg starting at the root.
236 * @param irg The graph.
237 * @param pre A pre-visitor to call.
238 * @param post A post-visitor to call.
239 * @param env Some private data to give to the visitors.
241 FIRM_API void postdom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
242 irg_walk_func *post, void *env);
244 /* ------------ Building and Removing the dominator data structure ----------- */
246 /** Computes the dominator trees.
248 * Sets a flag in irg to "dom_consistent".
249 * If the control flow of the graph is changed this flag must be set to
250 * "dom_inconsistent".
251 * Does not compute dominator information for control dead code. Blocks
252 * not reachable from Start contain the following information:
258 * Also constructs outs information. As this information is correct after
259 * the run does not free the outs information.
261 FIRM_API void compute_doms(ir_graph *irg);
263 /** Computes the dominator trees on demand, @see compute_doms(). */
264 FIRM_API void assure_doms(ir_graph *irg);
266 /** Computes the post dominator trees.
268 * Sets a flag in irg to "dom_consistent".
269 * If the control flow of the graph is changed this flag must be set to
270 * "dom_inconsistent".
271 * Does not compute post dominator information for endless lops. Blocks
272 * not reachable from End contain the following information:
278 * Also constructs outs information. As this information is correct after
279 * the run does not free the outs information.
281 FIRM_API void compute_postdoms(ir_graph *irg);
283 /** Computes the dominator trees on demand */
284 FIRM_API void assure_postdoms(ir_graph *irg);
286 /** Frees the dominator data structures. Sets the flag in irg to "dom_none". */
287 FIRM_API void free_dom(ir_graph *irg);
290 * Frees the post dominator data structures.
291 * Sets the flag in irg to "dom_none".
293 FIRM_API void free_postdom(ir_graph *irg);