nsz Git - libfirm/blob - ir/ana/heights.c

   1 /*
   2  * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   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.
  10  *
  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.
  14  *
  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
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  22  * @brief    Compute heights of nodes inside basic blocks
  23  * @author   Sebastian Hack
  24  * @date     19.04.2006
  25  * @version  $Id$
  26  */
  27 #include "config.h"
  28
  29 #include "heights.h"
  30
  31 #include <stdlib.h>
  32 #include <stdio.h>
  33 #include <stdbool.h>
  34
  35 #include "irdump.h"
  36 #include "irgwalk.h"
  37 #include "irnodemap.h"
  38 #include "iredges_t.h"
  39 #include "list.h"
  40 #include "util.h"
  41
  42 struct ir_heights_t {
  43         ir_nodemap      data;
  44         unsigned        visited;
  45         void           *dump_handle;
  46         struct obstack  obst;
  47 };
  48
  49 typedef struct {
  50         unsigned height;
  51         unsigned visited;
  52 } irn_height_t;
  53
  54 static irn_height_t *maybe_get_height_data(const ir_heights_t *heights,
  55                                            const ir_node *node)
  56 {
  57         irn_height_t *height = (irn_height_t*)ir_nodemap_get(&heights->data, node);
  58         return height;
  59 }
  60
  61 static irn_height_t *get_height_data(ir_heights_t *heights, const ir_node *node)
  62 {
  63         irn_height_t *height = (irn_height_t*)ir_nodemap_get(&heights->data, node);
  64         if (height == NULL) {
  65                 height = obstack_alloc(&heights->obst, sizeof(*height));
  66                 memset(height, 0, sizeof(*height));
  67                 ir_nodemap_insert(&heights->data, node, height);
  68         }
  69         return height;
  70 }
  71
  72 static void height_dump_cb(void *data, FILE *f, const ir_node *irn)
  73 {
  74         const ir_heights_t *heights = (const ir_heights_t*) data;
  75         const irn_height_t *h       = maybe_get_height_data(heights, irn);
  76         if (h != NULL)
  77                 fprintf(f, "height: %u\n", h->height);
  78 }
  79
  80 /**
  81  * Check, if we can reach a target node from a given node inside one basic block.
  82  * @param h    The heights object.
  83  * @param curr The current node from which we tried to reach the other one.
  84  * @param tgt  The node we try to reach.
  85  * @return     1, one of tgt can be reached from curr, 0 else.
  86  */
  87 static bool search(ir_heights_t *h, const ir_node *curr, const ir_node *tgt)
  88 {
  89         irn_height_t *h_curr;
  90         irn_height_t *h_tgt;
  91         int i, n;
  92
  93         /* if the current node is the one we were looking for, we're done. */
  94         if (curr == tgt)
  95                 return true;
  96
  97         /* If we are in another block or at a phi we won't find our target. */
  98         if (get_nodes_block(curr) != get_nodes_block(tgt))
  99                 return false;
 100         if (is_Phi(curr))
 101                 return false;
 102
 103         /* Check, if we have already been here. Coming more often won't help :-) */
 104         h_curr = get_height_data(h, curr);
 105         if (h_curr->visited >= h->visited)
 106                 return false;
 107
 108         /* If we are too deep into the DAG we won't find the target either. */
 109         h_tgt = get_height_data(h, tgt);
 110         if (h_curr->height > h_tgt->height)
 111                 return false;
 112
 113         /* Mark this place as visited. */
 114         h_curr->visited = h->visited;
 115
 116         /* Start a search from this node. */
 117         for (i = 0, n = get_irn_ins_or_deps(curr); i < n; ++i) {
 118                 ir_node *op = get_irn_in_or_dep(curr, i);
 119                 if (search(h, op, tgt))
 120                         return true;
 121         }
 122
 123         return false;
 124 }
 125
 126 /**
 127  * Check, if one node can be reached from another one, according to data
 128  * dependence.
 129  */
 130 int heights_reachable_in_block(ir_heights_t *h, const ir_node *n,
 131                                const ir_node *m)
 132 {
 133         int res          = 0;
 134         irn_height_t *hn = get_height_data(h, n);
 135         irn_height_t *hm = get_height_data(h, m);
 136
 137         assert(get_nodes_block(n) == get_nodes_block(m));
 138         assert(hn != NULL && hm != NULL);
 139
 140         if (hn->height <= hm->height) {
 141                 h->visited++;
 142                 res = search(h, n, m);
 143         }
 144
 145         return res;
 146 }
 147
 148 /**
 149  * Compute the height of a node in a block.
 150  * @param h   The heights object.
 151  * @param irn The node.
 152  * @param bl  The block.
 153  */
 154 static unsigned compute_height(ir_heights_t *h, ir_node *irn, const ir_node *bl)
 155 {
 156         irn_height_t *ih = get_height_data(h, irn);
 157
 158         const ir_edge_t *edge;
 159
 160         /* bail out if we already visited that node. */
 161         if (ih->visited >= h->visited)
 162                 return ih->height;
 163
 164         ih->visited = h->visited;
 165         ih->height  = 0;
 166
 167         foreach_out_edge(irn, edge) {
 168                 ir_node *dep = get_edge_src_irn(edge);
 169
 170                 if (!is_Block(dep) && !is_Phi(dep) && get_nodes_block(dep) == bl) {
 171                         unsigned dep_height = compute_height(h, dep, bl);
 172                         ih->height          = MAX(ih->height, dep_height);
 173                 }
 174
 175                 ih->height++;
 176         }
 177
 178         foreach_out_edge_kind(irn, edge, EDGE_KIND_DEP) {
 179                 ir_node *dep = get_edge_src_irn(edge);
 180
 181                 assert(!is_Phi(dep));
 182                 if (!is_Block(dep) && get_nodes_block(dep) == bl) {
 183                         unsigned dep_height = compute_height(h, dep, bl);
 184                         ih->height          = MAX(ih->height, dep_height);
 185                 }
 186
 187                 ih->height++;
 188         }
 189
 190         return ih->height;
 191 }
 192
 193 static unsigned compute_heights_in_block(ir_node *bl, ir_heights_t *h)
 194 {
 195         int             max_height = -1;
 196         const ir_edge_t *edge;
 197
 198         h->visited++;
 199
 200         foreach_out_edge(bl, edge) {
 201                 ir_node *dep = get_edge_src_irn(edge);
 202                 int     curh = compute_height(h, dep, bl);
 203
 204                 max_height = MAX(curh, max_height);
 205         }
 206
 207         foreach_out_edge_kind(bl, edge, EDGE_KIND_DEP) {
 208                 ir_node *dep = get_edge_src_irn(edge);
 209                 int     curh = compute_height(h, dep, bl);
 210
 211                 max_height = MAX(curh, max_height);
 212         }
 213
 214         return max_height;
 215 }
 216
 217 static void compute_heights_in_block_walker(ir_node *block, void *data)
 218 {
 219         ir_heights_t *h = (ir_heights_t*) data;
 220         compute_heights_in_block(block, h);
 221 }
 222
 223 unsigned get_irn_height(const ir_heights_t *heights, const ir_node *irn)
 224 {
 225         const irn_height_t *height = maybe_get_height_data(heights, irn);
 226         assert(height != NULL && "No height information for node");
 227         return height->height;
 228 }
 229
 230 unsigned heights_recompute_block(ir_heights_t *h, ir_node *block)
 231 {
 232         ir_graph *irg = get_irn_irg(block);
 233         const ir_edge_t *edge;
 234
 235         edges_assure(irg);
 236
 237         /* reset phase data for all nodes in the block */
 238         foreach_out_edge(block, edge) {
 239                 ir_node      *irn = get_edge_src_irn(edge);
 240                 irn_height_t *ih  = get_height_data(h, irn);
 241                 memset(ih, 0, sizeof(*ih));
 242         }
 243
 244         h->visited = 0;
 245         return compute_heights_in_block(block, h);
 246 }
 247
 248 ir_heights_t *heights_new(ir_graph *irg)
 249 {
 250         ir_heights_t *res = XMALLOC(ir_heights_t);
 251         ir_nodemap_init(&res->data, irg);
 252         obstack_init(&res->obst);
 253         res->dump_handle = dump_add_node_info_callback(height_dump_cb, res);
 254
 255         edges_assure(irg);
 256         irg_block_walk_graph(irg, compute_heights_in_block_walker, NULL, res);
 257
 258         return res;
 259 }
 260
 261 void heights_free(ir_heights_t *h)
 262 {
 263         dump_remove_node_info_callback(h->dump_handle);
 264         obstack_free(&h->obst, NULL);
 265         ir_nodemap_destroy(&h->data);
 266         xfree(h);
 267 }