2 * Copyright (C) 1995-2007 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 Compute heights of nodes inside basic blocks
23 * @author Sebastian Hack
39 #include "irphase_t.h"
40 #include "iredges_t.h"
42 typedef struct _heights_t heights_t;
55 static void *irn_height_init(ir_phase *ph, ir_node *irn, void *data)
57 irn_height_t *h = data ? data : phase_alloc(ph, sizeof(h[0]));
58 memset(h, 0, sizeof(h[0]));
62 static void height_dump_cb(void *data, FILE *f, const ir_node *irn)
64 heights_t *heights = data;
65 irn_height_t *h = phase_get_irn_data(&heights->ph, irn);
68 fprintf(f, "height: %u\n", h->height);
72 * Check, if we can reach a target node from a given node inside one basic block.
73 * @param h The heights object.
74 * @param curr The current node from which we tried to reach the other one.
75 * @param tgt The node we try to reach.
76 * @return 1, one of tgt can be reached from curr, 0 else.
78 static int search(heights_t *h, const ir_node *curr, const ir_node *tgt)
84 /* if the current node is the one we were looking for, we're done. */
88 /* If we are in another block or at a phi we won't find our target. */
89 if(get_nodes_block(curr) != get_nodes_block(tgt))
94 /* Check, if we have already been here. Coming more often won't help :-) */
95 h_curr = phase_get_irn_data(&h->ph, curr);
96 if(h_curr->visited >= h->visited)
99 /* If we are too deep into the DAG we won't find the target either. */
100 h_tgt = phase_get_irn_data(&h->ph, tgt);
101 if(h_curr->height > h_tgt->height)
104 /* Mark this place as visited. */
105 h_curr->visited = h->visited;
107 /* Start a search from this node. */
108 for(i = 0, n = get_irn_ins_or_deps(curr); i < n; ++i) {
109 ir_node *op = get_irn_in_or_dep(curr, i);
110 if(search(h, op, tgt))
118 * Check, if one node can be reached from another one, according to data dependence.
120 int heights_reachable_in_block(heights_t *h, const ir_node *n, const ir_node *m)
123 irn_height_t *hn = phase_get_irn_data(&h->ph, n);
124 irn_height_t *hm = phase_get_irn_data(&h->ph, m);
126 assert(get_nodes_block(n) == get_nodes_block(m));
127 assert(hn != NULL && hm != NULL);
129 if(hn->height <= hm->height) {
131 res = search(h, n, m);
138 * Compute the height of a node in a block.
139 * @param h The heights object.
140 * @param irn The node.
141 * @param bl The block.
143 static unsigned compute_height(heights_t *h, ir_node *irn, const ir_node *bl)
145 irn_height_t *ih = phase_get_or_set_irn_data(&h->ph, irn);
147 const ir_edge_t *edge;
149 /* bail out if we already visited that node. */
150 if(ih->visited >= h->visited)
153 ih->visited = h->visited;
156 foreach_out_edge(irn, edge) {
157 ir_node *dep = get_edge_src_irn(edge);
159 if(!is_Block(dep) && !is_Phi(dep) && get_nodes_block(dep) == bl) {
160 unsigned dep_height = compute_height(h, dep, bl);
161 ih->height = MAX(ih->height, dep_height);
167 foreach_out_edge_kind(irn, edge, EDGE_KIND_DEP) {
168 ir_node *dep = get_edge_src_irn(edge);
170 assert(!is_Phi(dep));
171 if(!is_Block(dep) && get_nodes_block(dep) == bl) {
172 unsigned dep_height = compute_height(h, dep, bl);
173 ih->height = MAX(ih->height, dep_height);
182 static unsigned compute_heights_in_block(ir_node *bl, heights_t *h)
185 const ir_edge_t *edge;
189 foreach_out_edge(bl, edge) {
190 ir_node *dep = get_edge_src_irn(edge);
191 int curh = compute_height(h, dep, bl);
193 max_height = MAX(curh, max_height);
196 foreach_out_edge_kind(bl, edge, EDGE_KIND_DEP) {
197 ir_node *dep = get_edge_src_irn(edge);
198 int curh = compute_height(h, dep, bl);
200 max_height = MAX(curh, max_height);
206 static void compute_heights_in_block_walker(ir_node *block, void *data)
209 compute_heights_in_block(block, h);
212 unsigned get_irn_height(heights_t *heights, const ir_node *irn)
214 irn_height_t *h = phase_get_irn_data(&heights->ph, irn);
215 assert(h && "No height information for node");
219 unsigned heights_recompute_block(heights_t *h, ir_node *block)
221 const ir_edge_t *edge;
223 edges_assure(phase_get_irg(&h->ph));
225 /* reset phase data for all nodes in the block */
226 foreach_out_edge(block, edge) {
227 ir_node *irn = get_edge_src_irn(edge);
228 irn_height_t *ih = phase_get_irn_data(&h->ph, irn);
230 irn_height_init(&h->ph, irn, ih);
234 return compute_heights_in_block(block, h);
237 void heights_recompute(heights_t *h)
239 edges_assure(phase_get_irg(&h->ph));
240 phase_reinit_irn_data(&h->ph);
242 irg_block_walk_graph(phase_get_irg(&h->ph), compute_heights_in_block_walker, NULL, h);
245 heights_t *heights_new(ir_graph *irg)
247 heights_t *res = xmalloc(sizeof(res[0]));
248 phase_init(&res->ph, "heights", irg, PHASE_DEFAULT_GROWTH, irn_height_init, NULL);
249 res->dump_handle = dump_add_node_info_callback(height_dump_cb, res);
250 heights_recompute(res);
255 void heights_free(heights_t *h)
258 dump_remv_node_info_callback(h->dump_handle);