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

   1 /*
   2  * Copyright (C) 1995-2007 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 an estimate of basic block executions.
  23  * @author      Adam M. Szalkowski
  24  * @date        28.05.2006
  25  * @version     $Id$
  26  */
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #undef USE_GSL
  32
  33 #include <stdio.h>
  34 #include <string.h>
  35 #include <limits.h>
  36 #include <math.h>
  37
  38 #ifdef USE_GSL
  39 #include <gsl/gsl_linalg.h>
  40 #include <gsl/gsl_vector.h>
  41 #else
  42 #include "gaussjordan.h"
  43 #endif
  44
  45 #include "firm_common_t.h"
  46 #include "set.h"
  47 #include "hashptr.h"
  48
  49 #include "irprog_t.h"
  50 #include "irgraph_t.h"
  51 #include "irnode_t.h"
  52 #include "irloop.h"
  53 #include "irgwalk.h"
  54 #include "iredges.h"
  55 #include "irprintf.h"
  56 #include "irhooks.h"
  57
  58 #include "execfreq.h"
  59
  60 #define set_foreach(s,i) for((i)=set_first((s)); (i); (i)=set_next((s)))
  61
  62 #define MAX_INT_FREQ 1000000
  63
  64 typedef struct _freq_t {
  65         const ir_node    *irn;
  66         double            freq;
  67 } freq_t;
  68
  69
  70 typedef struct _walkerdata_t {
  71   set    *set;
  72   size_t  idx;
  73 } walkerdata_t;
  74
  75 struct ir_exec_freq {
  76         set *set;
  77         hook_entry_t hook;
  78         double max;
  79         double min_non_zero;
  80         double m, b;
  81         unsigned infeasible : 1;
  82 };
  83
  84 static int
  85 cmp_freq(const void *a, const void *b, size_t size)
  86 {
  87         const freq_t *p = a;
  88         const freq_t *q = b;
  89
  90         return !(p->irn == q->irn);
  91 }
  92
  93 static freq_t *
  94 set_find_freq(set * set, const ir_node * irn)
  95 {
  96         freq_t     query;
  97
  98         query.irn = irn;
  99         return set_find(set, &query, sizeof(query), HASH_PTR(irn));
 100 }
 101
 102 static freq_t *
 103 set_insert_freq(set * set, const ir_node * irn)
 104 {
 105         freq_t query;
 106
 107         query.irn = irn;
 108         query.freq = 0.0;
 109         return set_insert(set, &query, sizeof(query), HASH_PTR(irn));
 110 }
 111
 112 double
 113 get_block_execfreq(const ir_exec_freq *ef, const ir_node * irn)
 114 {
 115         if(!ef->infeasible) {
 116                 set *freqs = ef->set;
 117                 freq_t *freq;
 118                 assert(is_Block(irn));
 119                 freq = set_find_freq(freqs, irn);
 120                 assert(freq);
 121
 122                 assert(freq->freq >= 0);
 123                 return freq->freq;
 124         }
 125
 126         return 1.0;
 127 }
 128
 129 unsigned long
 130 get_block_execfreq_ulong(const ir_exec_freq *ef, const ir_node *bb)
 131 {
 132         double f       = get_block_execfreq(ef, bb);
 133         int res        = (int) (f > ef->min_non_zero ? ef->m * f + ef->b : 1.0);
 134
 135         // printf("%20.6f %10d\n", f, res);
 136         return res;
 137 }
 138
 139 #define EPSILON         0.0001
 140 #define UNDEF(x)    !(x > EPSILON)
 141
 142 static void
 143 block_walker(ir_node * bb, void * data)
 144 {
 145   walkerdata_t  *wd = data;
 146
 147   set_insert_freq(wd->set, bb);
 148   set_irn_link(bb, (void*)wd->idx++);
 149 }
 150
 151 #ifdef USE_GSL
 152 static gsl_vector *
 153 solve_lgs(double * a_data, double * b_data, size_t size)
 154 {
 155   gsl_matrix_view m
 156     = gsl_matrix_view_array (a_data, size, size);
 157
 158   gsl_vector_view b
 159     = gsl_vector_view_array (b_data, size);
 160
 161   gsl_vector *x = gsl_vector_alloc (size);
 162
 163   int s;
 164
 165   gsl_permutation * p = gsl_permutation_alloc (size);
 166
 167   gsl_linalg_LU_decomp (&m.matrix, p, &s);
 168
 169   gsl_linalg_LU_solve (&m.matrix, p, &b.vector, x);
 170
 171   gsl_permutation_free (p);
 172
 173   return x;
 174 }
 175 #else
 176 static double *
 177 solve_lgs(double * A, double * b, size_t size)
 178 {
 179   if(firm_gaussjordansolve(A,b,size) == 0) {
 180     return b;
 181   } else {
 182     return NULL;
 183   }
 184 }
 185 #endif /* USE_GSL */
 186
 187 static double
 188 get_cf_probability(ir_node *bb, int pos, double loop_weight)
 189 {
 190         double  sum = 0.0;
 191         double  cur = 0.0;
 192         const ir_node *pred = get_Block_cfgpred_block(bb, pos);
 193         const ir_loop *pred_loop = get_irn_loop(pred);
 194         int pred_depth = get_loop_depth(pred_loop);
 195         const ir_edge_t *edge;
 196
 197         cur = get_loop_depth(get_irn_loop(bb)) < get_loop_depth(get_irn_loop(pred)) ? 1.0 : loop_weight;
 198
 199         foreach_block_succ(pred, edge) {
 200                 const ir_node *block = get_edge_src_irn(edge);
 201                 const ir_loop *loop = get_irn_loop(block);
 202                 int depth = get_loop_depth(loop);
 203                 sum += depth < pred_depth ? 1.0 : loop_weight;
 204         }
 205
 206         return cur/sum;
 207 }
 208
 209 static void exec_freq_node_info(void *ctx, FILE *f, const ir_node *irn)
 210 {
 211         if(is_Block(irn)) {
 212                 ir_exec_freq *ef = ctx;
 213                 fprintf(f, "execution frequency: %g/%lu\n", get_block_execfreq(ef, irn), get_block_execfreq_ulong(ef, irn));
 214         }
 215 }
 216
 217 ir_exec_freq *create_execfreq(ir_graph *irg)
 218 {
 219         ir_exec_freq *execfreq = xmalloc(sizeof(execfreq[0]));
 220         memset(execfreq, 0, sizeof(execfreq[0]));
 221         execfreq->set = new_set(cmp_freq, 32);
 222
 223         memset(&execfreq->hook, 0, sizeof(execfreq->hook));
 224         execfreq->hook.context = execfreq;
 225         execfreq->hook.hook._hook_node_info = exec_freq_node_info;
 226         register_hook(hook_node_info, &execfreq->hook);
 227
 228         return execfreq;
 229 }
 230
 231 void set_execfreq(ir_exec_freq *execfreq, const ir_node *block, double freq)
 232 {
 233         freq_t *f = set_insert_freq(execfreq->set, block);
 234         f->freq = freq;
 235 }
 236
 237 ir_exec_freq *
 238 compute_execfreq(ir_graph * irg, double loop_weight)
 239 {
 240         size_t        size;
 241         double       *matrix;
 242         double       *rhs;
 243         int           i;
 244         freq_t       *freq;
 245         walkerdata_t  wd;
 246         ir_exec_freq  *ef;
 247         set          *freqs;
 248 #ifdef USE_GSL
 249         gsl_vector   *x;
 250 #else
 251         double       *x;
 252 #endif
 253
 254         ef = xmalloc(sizeof(ef[0]));
 255         memset(ef, 0, sizeof(ef[0]));
 256         ef->min_non_zero = 1e50; /* initialize with a reasonable large number. */
 257         freqs = ef->set = new_set(cmp_freq, 32);
 258
 259         construct_cf_backedges(irg);
 260         edges_assure(irg);
 261
 262         wd.idx = 0;
 263         wd.set = freqs;
 264
 265         irg_block_walk_graph(irg, block_walker, NULL, &wd);
 266
 267         size = set_count(freqs);
 268         matrix = xmalloc(size*size*sizeof(*matrix));
 269         memset(matrix, 0, size*size*sizeof(*matrix));
 270         rhs = xmalloc(size*sizeof(*rhs));
 271         memset(rhs, 0, size*sizeof(*rhs));
 272
 273         set_foreach(freqs, freq) {
 274                 ir_node *bb = (ir_node *)freq->irn;
 275                 size_t  idx = (int)get_irn_link(bb);
 276
 277                 matrix[idx * (size + 1)] = -1.0;
 278
 279                 if (bb == get_irg_start_block(irg)) {
 280                         rhs[(int)get_irn_link(bb)] = -1.0;
 281                         continue;
 282                 }
 283
 284                 for(i = get_Block_n_cfgpreds(bb) - 1; i >= 0; --i) {
 285                         ir_node *pred    = get_Block_cfgpred_block(bb, i);
 286                         size_t  pred_idx = (int)get_irn_link(pred);
 287
 288                         //      matrix[pred_idx + idx*size] += 1.0/(double)get_Block_n_cfg_outs(pred);
 289                         matrix[pred_idx + idx * size] += get_cf_probability(bb, i, loop_weight);
 290                 }
 291         }
 292
 293         x = solve_lgs(matrix, rhs, size);
 294         if (x == NULL) {
 295                 ef->infeasible = 1;
 296         } else {
 297                 ef->max = 0.0;
 298
 299                 set_foreach(freqs, freq) {
 300                         const ir_node *bb = freq->irn;
 301                         size_t        idx = PTR_TO_INT(get_irn_link(bb));
 302
 303 #ifdef USE_GSL
 304                         freq->freq = UNDEF(gsl_vector_get(x, idx)) ? EPSILON : gsl_vector_get(x, idx);
 305 #else
 306                         freq->freq = UNDEF(x[idx]) ? EPSILON : x[idx];
 307 #endif
 308
 309                         /* get the maximum exec freq */
 310                         ef->max = MAX(ef->max, freq->freq);
 311
 312                         /* Get the minimum non-zero execution frequency. */
 313                         if(freq->freq > 0.0)
 314                                 ef->min_non_zero = MIN(ef->min_non_zero, freq->freq);
 315                 }
 316
 317                 /* compute m and b of the transformation used to convert the doubles into scaled ints */
 318                 {
 319                         double smallest_diff = 1.0;
 320
 321                         double l2 = ef->min_non_zero;
 322                         double h2 = ef->max;
 323                         double l1 = 1.0;
 324                         double h1 = MAX_INT_FREQ;
 325
 326                         double *fs = malloc(set_count(freqs) * sizeof(fs[0]));
 327                         int i, j, n = 0;
 328
 329                         set_foreach(freqs, freq)
 330                                 fs[n++] = freq->freq;
 331
 332                         /*
 333                          * find the smallest difference of the execution frequencies
 334                          * we try to ressolve it with 1 integer.
 335                          */
 336                         for(i = 0; i < n; ++i) {
 337                                 if(fs[i] <= 0.0)
 338                                         continue;
 339
 340                                 for(j = i + 1; j < n; ++j) {
 341                                         double diff = fabs(fs[i] - fs[j]);
 342
 343                                         if(!UNDEF(diff))
 344                                                 smallest_diff = MIN(diff, smallest_diff);
 345                                 }
 346                         }
 347
 348                         /* according to that the slope of the translation function is 1.0 / smallest diff */
 349                         ef->m = 1.0 / smallest_diff;
 350
 351                         /* the abscissa is then given by */
 352                         ef->b = l1 - ef->m * l2;
 353
 354                         /*
 355                          * if the slope is so high that the largest integer would be larger than MAX_INT_FREQ
 356                          * set the largest int freq to that upper limit and recompute the translation function
 357                          */
 358                         if(ef->m * h2 + ef->b > MAX_INT_FREQ) {
 359                                 ef->m = (h1 - l1) / (h2 - l2);
 360                                 ef->b = l1 - ef->m * l2;
 361                         }
 362
 363                         // printf("smallest_diff: %g, l1: %f, h1: %f, l2: %f, h2: %f, m: %f, b: %f\n", smallest_diff, l1, h1, l2, h2, ef->m, ef->b);
 364                         free(fs);
 365                 }
 366
 367 #ifdef USE_GSL
 368                 gsl_vector_free(x);
 369 #endif
 370                 memset(&ef->hook, 0, sizeof(ef->hook));
 371                 ef->hook.context = ef;
 372                 ef->hook.hook._hook_node_info = exec_freq_node_info;
 373                 register_hook(hook_node_info, &ef->hook);
 374         }
 375
 376         free(matrix);
 377         free(rhs);
 378
 379         return ef;
 380 }
 381
 382 void
 383 free_execfreq(ir_exec_freq *ef)
 384 {
 385         del_set(ef->set);
 386         unregister_hook(hook_node_info, &ef->hook);
 387         free(ef);
 388 }