3 * File name: ir/ana/irdom.h
4 * Purpose: Construct and access dominator tree.
5 * Author: Goetz Lindenmaier
9 * Copyright: (c) 2002-2003 Universität Karlsruhe
10 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
16 * This file contains routines to construct and access dominator information.
18 * The dominator information is stored in three fields of block nodes:
19 * - idom: a reference to the block that is the immediate dominator of
21 * - dom_depth: a number giving the depth of the block in the dominator
23 * - pre_num: Number in preorder traversal.
25 * @author Goetz Lindenmaier
37 /** Accessing the dominator data structure.
39 * These routines only work properly if the ir_graph is in state
40 * dom_consistent or dom_inconsistent.
42 * If the block is not reachable from Start, returns a Bad node.
44 ir_node *get_Block_idom(const ir_node *bl);
45 void set_Block_idom(ir_node *bl, ir_node *n);
47 int get_Block_dom_depth(const ir_node *bl);
48 void set_Block_dom_depth(ir_node *bl, int depth);
50 int get_Block_pre_num(const ir_node *bl);
51 void set_Block_pre_num(ir_node *bl, int num);
54 * Get the pre-order number of a block resulting from a
55 * Depth-First-Search walkover the dominator tree.
57 * @param bl The block.
58 * @return The pre-order number.
60 unsigned get_Block_dom_tree_pre_num(const ir_node *bl);
63 * Get the largest pre-order number found in the subtree of the
64 * dominator tree rooted at a given block.
65 * @param bl The block.
66 * @return The largest pre-order number of block's dominator subtree.
68 unsigned get_Block_dom_max_subtree_pre_num(const ir_node *bl);
71 * Get the first node in the list of nodes dominated by a given block.
73 * Each node keeps a list of nodes which it immediately dominates. The
74 * nodes are queued using the @c next pointer in the @c dom_info struct.
75 * Each node keeps a head of this list using the pointer @c first in the
78 * @param bl The block for which to get the first node dominated by @c bl.
79 * @return The first node dominated by @p bl.
81 ir_node *get_Block_dominated_first(const ir_node *bl);
84 * Get the next node in a list of nodes which are dominated by some
86 * @see get_Block_dominated_first().
87 * @param dom The previous node.
88 * @return The next node in this list or NULL if it was the last.
90 ir_node *get_Block_dominated_next(const ir_node *dom);
93 * Iterate over all nodes which are immediately dominated by a given
95 * @param bl The block whose dominated blocks shall be iterated on.
96 * @param curr An iterator variable of type ir_node*
98 #define dominates_for_each(bl,curr) \
99 for(curr = get_Block_dominated_first(bl); curr; \
100 curr = get_Block_dominated_next(curr))
103 * Check, if a block dominates another block.
104 * @param a The first block.
105 * @param b The second block.
106 * @return 1, if @p a dominates @p b, else 0.
108 int block_dominates(const ir_node *a, const ir_node *b);
111 * Visit all nodes in the dominator subtree of a given node.
112 * Call a pre-visitor before descending to the children and call a
113 * post-visitor after returning from them.
114 * @param n The node to start walking from.
115 * @param pre The pre-visitor callback.
116 * @param post The post-visitor callback.
117 * @param env Some custom data passed to the visitors.
119 void dom_tree_walk(ir_node *n, irg_walk_func *pre,
120 irg_walk_func *post, void *env);
124 * Walk over the dominator tree of an irg starting at the root.
125 * @param irg The graph.
126 * @param pre A pre-visitor to call.
127 * @param post A post-visitor to call.
128 * @param env Some private data to give to the visitors.
130 void dom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
131 irg_walk_func *post, void *env);
133 /* ------------ Building and Removing the dominator data structure ----------- */
135 /** Computes the dominator trees.
137 * Sets a flag in irg to "dom_consistent".
138 * If the control flow of the graph is changed this flag must be set to
139 * "dom_inconsistent".
140 * Does not compute dominator information for control dead code. Blocks
141 * not reachable from Start contain the following information:
147 * Also constructs outs information. As this information is correct after
148 * the run does not free the outs information.
150 void compute_doms(ir_graph *irg);
152 /** Frees the dominator data structures. Sets the flag in irg to "dom_none". */
153 void free_dom_and_peace(ir_graph *irg);
155 #endif /* _IRDOM_H_ */