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 Implementation of cdep
38 typedef struct cdep_info {
39 pmap *cdep_map; /**< A map to find the list of all control dependence nodes for a block. */
40 struct obstack obst; /**< An obstack where all cdep data lives on. */
43 static cdep_info *cdep_data;
45 /* Return a list of all control dependences of a block. */
46 ir_cdep *find_cdep(const ir_node *block) {
47 return pmap_get(cdep_data->cdep_map, (void *)block);
50 /* Replace the control dependence info of old by the info of nw. */
51 void exchange_cdep(ir_node *old, const ir_node *nw) {
52 ir_cdep *cdep = find_cdep(nw);
53 pmap_insert(cdep_data->cdep_map, old, cdep);
57 * Adds a control dependence from node to dep_on.
59 static void add_cdep(ir_node *node, ir_node *dep_on) {
60 ir_cdep *dep = find_cdep(node);
62 ir_fprintf(stderr, "Adding cdep of %+F on %+F\n", node, dep_on);
66 ir_cdep *newdep = obstack_alloc(&cdep_data->obst, sizeof(*newdep));
68 newdep->node = dep_on;
70 pmap_insert(cdep_data->cdep_map, node, newdep);
75 if (dep->node == dep_on) return;
76 if (dep->next == NULL) break;
79 newdep = obstack_alloc(&cdep_data->obst, sizeof(*newdep));
80 newdep->node = dep_on;
86 typedef struct cdep_env {
92 * Pre-block-walker: calculate the control dependence
94 static void cdep_pre(ir_node *node, void *ctx) {
100 * start and end block have no control dependency
102 if (node == env->start_block) return;
103 if (node == env->end_block) return;
105 n = get_Block_n_cfgpreds(node);
106 for (i = 0; i < n; i++) {
107 ir_node *pred = get_Block_cfgpred_block(node, i);
111 if (is_Bad(pred)) continue;
113 pdom = get_Block_ipostdom(pred);
114 for (dependee = node; dependee != pdom; dependee = get_Block_ipostdom(dependee)) {
115 assert(!is_Bad(pdom));
116 add_cdep(dependee, pred);
123 * A block edge hook: add all cdep edges of block.
125 static int cdep_edge_hook(FILE *F, ir_node *block)
130 ir_node *pdom = get_Block_ipostdom(block);
134 "edge:{sourcename:\"n%ld\" targetname:\"n%ld\" color:gold}\n",
135 get_irn_node_nr(pdom), get_irn_node_nr(block)
140 for (cd = find_cdep(block); cd != NULL; cd = cd->next) {
143 "edge:{sourcename:\"n%ld\" targetname:\"n%ld\" "
144 "linestyle:dashed color:gold}\n",
145 get_irn_node_nr(block), get_irn_node_nr(cd->node)
152 /* Compute the control dependence graph for a graph. */
153 void compute_cdep(ir_graph *irg) {
154 ir_node *start_block, *rem;
158 cdep_data = xmalloc(sizeof(*cdep_data));
159 obstack_init(&cdep_data->obst);
161 cdep_data->cdep_map = pmap_create();
163 assure_postdoms(irg);
165 /* we must temporary change the post dominator relation:
166 the ipdom of the startblock is the end block.
167 Firm does NOT add the phantom edge from Start to End.
169 start_block = get_irg_start_block(irg);
170 rem = get_Block_ipostdom(start_block);
171 set_Block_ipostdom(start_block, get_irg_end_block(irg));
173 env.start_block = get_irg_start_block(irg);
174 env.end_block = get_irg_end_block(irg);
175 irg_block_walk_graph(irg, cdep_pre, NULL, &env);
178 set_dump_block_edge_hook(cdep_edge_hook);
179 dump_ir_block_graph(irg, "_cdep");
180 set_dump_block_edge_hook(NULL);
182 (void) cdep_edge_hook;
185 /* restore the post dominator relation */
186 set_Block_ipostdom(start_block, rem);
189 /* Free the control dependence info. */
190 void free_cdep(ir_graph *irg) {
192 if (cdep_data != NULL) {
193 pmap_destroy(cdep_data->cdep_map);
194 obstack_free(&cdep_data->obst, NULL);
200 /* Check whether dependee is (directly) control dependent on candidate. */
201 int is_cdep_on(const ir_node *dependee, const ir_node *candidate) {
204 for (dep = find_cdep(dependee); dep != NULL; dep = dep->next) {
205 if (dep->node == candidate) return 1;
210 /* Check whether dependee is (possible iterated) control dependent on candidate. */
211 int is_iterated_cdep_on(ir_node *dependee, ir_node *candidate) {
214 while ((dep = find_cdep(dependee)) != NULL) {
215 if (dep->next != NULL) return 0;
216 if (dep->node == candidate) return 1;
217 dependee = dep->node;
222 /* If block is control dependent on exactly one node, return this node, else NULL. */
223 ir_node *get_unique_cdep(const ir_node *block) {
224 ir_cdep *cdep = find_cdep(block);
226 return cdep != NULL && cdep->next == NULL ? cdep->node : NULL;
229 /* Check if the given block is control dependent of more than one node. */
230 int has_multiple_cdep(const ir_node *block) {
231 ir_cdep *cdep = find_cdep(block);
233 return cdep != NULL && cdep->next != NULL;