3 * File name: ir/ana/height.c
4 * Purpose: Compute heights of nodes inside basic blocks
5 * Author: Sebastian Hack
9 * Copyright: (c) 2006 Universität Karlsruhe
10 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
25 #include "irphase_t.h"
26 #include "iredges_t.h"
28 typedef struct _heights_t heights_t;
41 static void *irn_height_init(phase_t *ph, ir_node *irn, void *data)
43 irn_height_t *h = data ? data : phase_alloc(ph, sizeof(h[0]));
44 memset(h, 0, sizeof(h[0]));
48 static void height_dump_cb(void *data, FILE *f, const ir_node *irn)
50 heights_t *heights = data;
51 irn_height_t *h = phase_get_irn_data(&heights->ph, irn);
54 fprintf(f, "height: %u\n", h->height);
58 * Check, if we can reach a target node from a given node inside one basic block.
59 * @param h The heights object.
60 * @param curr The current node from which we tried to reach the other one.
61 * @param tgt The node we try to reach.
62 * @return 1, one of tgt can be reached from curr, 0 else.
64 static int search(heights_t *h, const ir_node *curr, const ir_node *tgt)
70 /* if the current node is the one we were looking for, we're done. */
74 /* If we are in another block we won't find our target. */
75 if(get_nodes_block(curr) != get_nodes_block(tgt))
78 /* Check, if we have already been here. Coming more often won't help :-) */
79 h_curr = phase_get_irn_data(&h->ph, curr);
80 if(h_curr->visited >= h->visited)
83 /* If we are too deep into the DAG we won't find the target either. */
84 h_tgt = phase_get_irn_data(&h->ph, tgt);
85 if(h_curr->height > h_tgt->height)
88 /* Mark this place as visited. */
89 h_curr->visited = h->visited;
91 /* Start a search from this node. */
92 for(i = 0, n = get_irn_ins_or_deps(curr); i < n; ++i) {
93 ir_node *op = get_irn_in_or_dep(curr, i);
94 if(search(h, op, tgt))
102 * Check, if one node can be reached from another one, according to data dependence.
104 int heights_reachable_in_block(heights_t *h, const ir_node *n, const ir_node *m)
107 irn_height_t *hn = phase_get_irn_data(&h->ph, n);
108 irn_height_t *hm = phase_get_irn_data(&h->ph, m);
110 assert(get_nodes_block(n) == get_nodes_block(m));
111 assert(hn != NULL && hm != NULL);
113 if(hn->height <= hm->height) {
115 res = search(h, n, m);
122 * Compute the height of a node in a block.
123 * @param h The heights object.
124 * @param irn The node.
125 * @param bl The block.
127 static unsigned compute_height(heights_t *h, ir_node *irn, const ir_node *bl)
129 irn_height_t *ih = phase_get_or_set_irn_data(&h->ph, irn);
131 const ir_edge_t *edge;
133 /* bail out if we already visited that node. */
134 if(ih->visited >= h->visited)
137 ih->visited = h->visited;
140 foreach_out_edge(irn, edge) {
141 ir_node *dep = get_edge_src_irn(edge);
143 if(!is_Block(dep) && get_nodes_block(dep) == bl) {
144 unsigned dep_height = compute_height(h, dep, bl);
145 ih->height = MAX(ih->height, dep_height);
151 foreach_out_edge_kind(irn, edge, EDGE_KIND_DEP) {
152 ir_node *dep = get_edge_src_irn(edge);
154 if(!is_Block(dep) && get_nodes_block(dep) == bl) {
155 unsigned dep_height = compute_height(h, dep, bl);
156 ih->height = MAX(ih->height, dep_height);
165 static unsigned compute_heights_in_block(ir_node *bl, heights_t *h)
168 const ir_edge_t *edge;
172 foreach_out_edge(bl, edge) {
173 ir_node *dep = get_edge_src_irn(edge);
174 int curh = compute_height(h, dep, bl);
176 max_height = MAX(curh, max_height);
179 foreach_out_edge_kind(bl, edge, EDGE_KIND_DEP) {
180 ir_node *dep = get_edge_src_irn(edge);
181 int curh = compute_height(h, dep, bl);
183 max_height = MAX(curh, max_height);
189 static void compute_heights_in_block_walker(ir_node *block, void *data)
192 compute_heights_in_block(block, h);
195 unsigned get_irn_height(heights_t *heights, const ir_node *irn)
197 irn_height_t *h = phase_get_irn_data(&heights->ph, irn);
198 assert(h && "No height information for node");
202 unsigned heights_recompute_block(heights_t *h, ir_node *block)
204 const ir_edge_t *edge;
206 edges_assure(phase_get_irg(&h->ph));
208 /* reset phase data for all nodes in the block */
209 foreach_out_edge(block, edge) {
210 ir_node *irn = get_edge_src_irn(edge);
211 irn_height_t *ih = phase_get_irn_data(&h->ph, irn);
213 irn_height_init(&h->ph, irn, ih);
217 return compute_heights_in_block(block, h);
220 void heights_recompute(heights_t *h)
222 edges_assure(phase_get_irg(&h->ph));
223 phase_reinit_irn_data(&h->ph);
225 irg_block_walk_graph(phase_get_irg(&h->ph), compute_heights_in_block_walker, NULL, h);
228 heights_t *heights_new(ir_graph *irg)
230 heights_t *res = xmalloc(sizeof(res[0]));
231 phase_init(&res->ph, "heights", irg, PHASE_DEFAULT_GROWTH, irn_height_init);
232 res->dump_handle = dump_add_node_info_callback(height_dump_cb, res);
233 heights_recompute(res);
238 void heights_free(heights_t *h)
241 dump_remv_node_info_callback(h->dump_handle);