2 * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
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9 * packaging of this file.
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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 ir_node *get_Block_idom(const ir_node *bl);
50 void set_Block_idom(ir_node *bl, ir_node *n);
52 int get_Block_dom_depth(const ir_node *bl);
53 void set_Block_dom_depth(ir_node *bl, int depth);
55 int get_Block_dom_pre_num(const ir_node *bl);
56 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 ir_node *get_Block_ipostdom(const ir_node *bl);
66 void set_Block_ipostdom(ir_node *bl, ir_node *n);
68 int get_Block_postdom_depth(const ir_node *bl);
69 void set_Block_postdom_depth(ir_node *bl, int depth);
71 int get_Block_postdom_pre_num(const ir_node *bl);
72 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 unsigned get_Block_dom_tree_pre_num(const ir_node *bl);
84 * Get the largest pre-order number found in the subtree of the
85 * dominator tree rooted at a given block.
86 * @param bl The block.
87 * @return The largest pre-order number of block's dominator subtree.
89 unsigned get_Block_dom_max_subtree_pre_num(const ir_node *bl);
92 * Get the first node in the list of nodes dominated by a given block.
94 * Each node keeps a list of nodes which it immediately dominates. The
95 * nodes are queued using the @c next pointer in the @c dom_info struct.
96 * Each node keeps a head of this list using the pointer @c first in the
99 * @param bl The block for which to get the first node dominated by @c bl.
100 * @return The first node dominated by @p bl.
102 ir_node *get_Block_dominated_first(const ir_node *bl);
105 * Get the next node in a list of nodes which are dominated by some
107 * @see get_Block_dominated_first().
108 * @param dom The previous node.
109 * @return The next node in this list or NULL if it was the last.
111 ir_node *get_Block_dominated_next(const ir_node *dom);
114 * Iterate over all nodes which are immediately dominated by a given
116 * @param bl The block whose dominated blocks shall be iterated on.
117 * @param curr An iterator variable of type ir_node*
119 #define dominates_for_each(bl,curr) \
120 for(curr = get_Block_dominated_first(bl); curr; \
121 curr = get_Block_dominated_next(curr))
124 * Iterate over all nodes which are immediately post dominated by a given
126 * @param bl The block whose post dominated blocks shall be iterated on.
127 * @param curr An iterator variable of type ir_node*
129 #define postdominates_for_each(bl,curr) \
130 for(curr = get_Block_postdominated_first(bl); curr; \
131 curr = get_Block_postdominated_next(curr))
134 * Check, if a block dominates another block.
136 * @param a The potential dominator block.
137 * @param b The potentially dominated block.
139 * @return 1, if @p a dominates @p b, else 0.
141 int block_dominates(const ir_node *a, const ir_node *b);
144 * Check, if a block strictly dominates another block, i.e. a != b.
146 * @param a The potential dominator block.
147 * @param b The potentially dominated block.
149 * @return 1, if @p a strictly dominates @p b, else 0.
151 int block_strictly_dominates(const ir_node *a, const ir_node *b);
154 * Returns the smallest common dominator block of two nodes.
156 * @param b Another node.
157 * @return The first block dominating @p a and @p b
159 ir_node *node_smallest_common_dominator(ir_node *a, ir_node *b);
162 * Returns the smallest common dominator block of all users of a node
163 * BEWARE: @p irn must not be a block
164 * If on or more users are Phi nodes, one can request special handling
165 * with @p handle_phi = 1. In this case the cfg predecessor block
166 * corresponding to the position of the irn in the argument list of the
167 * Phi is determined and treated as user.
170 * @param handle_phi 1 if Phis should be handled different
171 * @return The first block dominating all users of @irn
173 ir_node *node_users_smallest_common_dominator(ir_node *irn, int handle_phi);
176 * Check, if a block post dominates another block.
178 * @param a The potential post dominator block.
179 * @param b The potentially post dominated block.
181 * @return 1, if @p a post dominates @p b, else 0.
183 int block_postdominates(const ir_node *a, const ir_node *b);
186 * Check, if a block strictly post dominates another block, i.e. a != b.
188 * @param a The potential post dominator block.
189 * @param b The potentially post dominated block.
191 * @return 1, if @p a strictly post dominates @p b, else 0.
193 int block_strictly_postdominates(const ir_node *a, const ir_node *b);
196 * Visit all nodes in the dominator subtree of a given node.
197 * Call a pre-visitor before descending to the children and call a
198 * post-visitor after returning from them.
199 * @param n The node to start walking from.
200 * @param pre The pre-visitor callback.
201 * @param post The post-visitor callback.
202 * @param env Some custom data passed to the visitors.
204 void dom_tree_walk(ir_node *n, irg_walk_func *pre,
205 irg_walk_func *post, void *env);
208 * Visit all nodes in the post dominator subtree of a given node.
209 * Call a pre-visitor before descending to the children and call a
210 * post-visitor after returning from them.
211 * @param n The node to start walking from.
212 * @param pre The pre-visitor callback.
213 * @param post The post-visitor callback.
214 * @param env Some custom data passed to the visitors.
216 void postdom_tree_walk(ir_node *n, irg_walk_func *pre,
217 irg_walk_func *post, void *env);
220 * Walk over the dominator tree of an irg starting at the root.
221 * @param irg The graph.
222 * @param pre A pre-visitor to call.
223 * @param post A post-visitor to call.
224 * @param env Some private data to give to the visitors.
226 void dom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
227 irg_walk_func *post, void *env);
230 * Walk over the post dominator tree of an irg starting at the root.
231 * @param irg The graph.
232 * @param pre A pre-visitor to call.
233 * @param post A post-visitor to call.
234 * @param env Some private data to give to the visitors.
236 void postdom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
237 irg_walk_func *post, void *env);
239 /* ------------ Building and Removing the dominator data structure ----------- */
241 /** Computes the dominator trees.
243 * Sets a flag in irg to "dom_consistent".
244 * If the control flow of the graph is changed this flag must be set to
245 * "dom_inconsistent".
246 * Does not compute dominator information for control dead code. Blocks
247 * not reachable from Start contain the following information:
253 * Also constructs outs information. As this information is correct after
254 * the run does not free the outs information.
256 void compute_doms(ir_graph *irg);
258 /** Computes the dominator trees on demand */
259 void assure_doms(ir_graph *irg);
261 /** Computes the post dominator trees.
263 * Sets a flag in irg to "dom_consistent".
264 * If the control flow of the graph is changed this flag must be set to
265 * "dom_inconsistent".
266 * Does not compute post dominator information for endless lops. Blocks
267 * not reachable from End contain the following information:
273 * Also constructs outs information. As this information is correct after
274 * the run does not free the outs information.
276 void compute_postdoms(ir_graph *irg);
278 /** Computes the dominator trees on demand */
279 void assure_postdoms(ir_graph *irg);
281 /** Frees the dominator data structures. Sets the flag in irg to "dom_none". */
282 void free_dom(ir_graph *irg);
284 /** Frees the post dominator data structures. Sets the flag in irg to "dom_none". */
285 void free_postdom(ir_graph *irg);