Mercurial > hg > CbC > CbC_gcc
annotate gcc/tracer.c @ 55:77e2b8dfacca gcc-4.4.5
update it from 4.4.3 to 4.5.0
| author | ryoma <e075725@ie.u-ryukyu.ac.jp> |
|---|---|
| date | Fri, 12 Feb 2010 23:39:51 +0900 |
| parents | a06113de4d67 |
| children | 04ced10e8804 |
| rev | line source |
|---|---|
| 0 | 1 /* The tracer pass for the GNU compiler. |
| 2 Contributed by Jan Hubicka, SuSE Labs. | |
| 3 Adapted to work on GIMPLE instead of RTL by Robert Kidd, UIUC. | |
| 4 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 | |
| 5 Free Software Foundation, Inc. | |
| 6 | |
| 7 This file is part of GCC. | |
| 8 | |
| 9 GCC is free software; you can redistribute it and/or modify it | |
| 10 under the terms of the GNU General Public License as published by | |
| 11 the Free Software Foundation; either version 3, or (at your option) | |
| 12 any later version. | |
| 13 | |
| 14 GCC is distributed in the hope that it will be useful, but WITHOUT | |
| 15 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
| 16 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public | |
| 17 License for more details. | |
| 18 | |
| 19 You should have received a copy of the GNU General Public License | |
| 20 along with GCC; see the file COPYING3. If not see | |
| 21 <http://www.gnu.org/licenses/>. */ | |
| 22 | |
| 23 /* This pass performs the tail duplication needed for superblock formation. | |
| 24 For more information see: | |
| 25 | |
| 26 Design and Analysis of Profile-Based Optimization in Compaq's | |
| 27 Compilation Tools for Alpha; Journal of Instruction-Level | |
| 28 Parallelism 3 (2000) 1-25 | |
| 29 | |
| 30 Unlike Compaq's implementation we don't do the loop peeling as most | |
| 31 probably a better job can be done by a special pass and we don't | |
| 32 need to worry too much about the code size implications as the tail | |
| 33 duplicates are crossjumped again if optimizations are not | |
| 34 performed. */ | |
| 35 | |
| 36 | |
| 37 #include "config.h" | |
| 38 #include "system.h" | |
| 39 #include "coretypes.h" | |
| 40 #include "tm.h" | |
| 41 #include "tree.h" | |
| 42 #include "rtl.h" | |
| 43 #include "hard-reg-set.h" | |
| 44 #include "basic-block.h" | |
| 45 #include "output.h" | |
| 46 #include "cfglayout.h" | |
| 47 #include "fibheap.h" | |
| 48 #include "flags.h" | |
| 49 #include "timevar.h" | |
| 50 #include "params.h" | |
| 51 #include "coverage.h" | |
| 52 #include "tree-pass.h" | |
| 53 #include "tree-flow.h" | |
| 54 #include "tree-inline.h" | |
| 55 | |
| 56 static int count_insns (basic_block); | |
| 57 static bool ignore_bb_p (const_basic_block); | |
| 58 static bool better_p (const_edge, const_edge); | |
| 59 static edge find_best_successor (basic_block); | |
| 60 static edge find_best_predecessor (basic_block); | |
| 61 static int find_trace (basic_block, basic_block *); | |
| 62 static void tail_duplicate (void); | |
| 63 | |
| 64 /* Minimal outgoing edge probability considered for superblock formation. */ | |
| 65 static int probability_cutoff; | |
| 66 static int branch_ratio_cutoff; | |
| 67 | |
| 68 /* A bit BB->index is set if BB has already been seen, i.e. it is | |
| 69 connected to some trace already. */ | |
| 70 sbitmap bb_seen; | |
| 71 | |
| 72 static inline void | |
| 73 mark_bb_seen (basic_block bb) | |
| 74 { | |
| 75 unsigned int size = SBITMAP_SIZE_BYTES (bb_seen) * 8; | |
| 76 | |
| 77 if ((unsigned int)bb->index >= size) | |
| 78 bb_seen = sbitmap_resize (bb_seen, size * 2, 0); | |
| 79 | |
| 80 SET_BIT (bb_seen, bb->index); | |
| 81 } | |
| 82 | |
| 83 static inline bool | |
| 84 bb_seen_p (basic_block bb) | |
| 85 { | |
| 86 return TEST_BIT (bb_seen, bb->index); | |
| 87 } | |
| 88 | |
| 89 /* Return true if we should ignore the basic block for purposes of tracing. */ | |
| 90 static bool | |
| 91 ignore_bb_p (const_basic_block bb) | |
| 92 { | |
| 93 if (bb->index < NUM_FIXED_BLOCKS) | |
| 94 return true; | |
| 95 if (optimize_bb_for_size_p (bb)) | |
| 96 return true; | |
| 97 return false; | |
| 98 } | |
| 99 | |
| 100 /* Return number of instructions in the block. */ | |
| 101 | |
| 102 static int | |
| 103 count_insns (basic_block bb) | |
| 104 { | |
| 105 gimple_stmt_iterator gsi; | |
| 106 gimple stmt; | |
| 107 int n = 0; | |
| 108 | |
| 109 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
| 110 { | |
| 111 stmt = gsi_stmt (gsi); | |
| 112 n += estimate_num_insns (stmt, &eni_size_weights); | |
| 113 } | |
| 114 return n; | |
| 115 } | |
| 116 | |
| 117 /* Return true if E1 is more frequent than E2. */ | |
| 118 static bool | |
| 119 better_p (const_edge e1, const_edge e2) | |
| 120 { | |
| 121 if (e1->count != e2->count) | |
| 122 return e1->count > e2->count; | |
| 123 if (e1->src->frequency * e1->probability != | |
| 124 e2->src->frequency * e2->probability) | |
| 125 return (e1->src->frequency * e1->probability | |
| 126 > e2->src->frequency * e2->probability); | |
| 127 /* This is needed to avoid changes in the decision after | |
| 128 CFG is modified. */ | |
| 129 if (e1->src != e2->src) | |
| 130 return e1->src->index > e2->src->index; | |
| 131 return e1->dest->index > e2->dest->index; | |
| 132 } | |
| 133 | |
| 134 /* Return most frequent successor of basic block BB. */ | |
| 135 | |
| 136 static edge | |
| 137 find_best_successor (basic_block bb) | |
| 138 { | |
| 139 edge e; | |
| 140 edge best = NULL; | |
| 141 edge_iterator ei; | |
| 142 | |
| 143 FOR_EACH_EDGE (e, ei, bb->succs) | |
| 144 if (!best || better_p (e, best)) | |
| 145 best = e; | |
| 146 if (!best || ignore_bb_p (best->dest)) | |
| 147 return NULL; | |
| 148 if (best->probability <= probability_cutoff) | |
| 149 return NULL; | |
| 150 return best; | |
| 151 } | |
| 152 | |
| 153 /* Return most frequent predecessor of basic block BB. */ | |
| 154 | |
| 155 static edge | |
| 156 find_best_predecessor (basic_block bb) | |
| 157 { | |
| 158 edge e; | |
| 159 edge best = NULL; | |
| 160 edge_iterator ei; | |
| 161 | |
| 162 FOR_EACH_EDGE (e, ei, bb->preds) | |
| 163 if (!best || better_p (e, best)) | |
| 164 best = e; | |
| 165 if (!best || ignore_bb_p (best->src)) | |
| 166 return NULL; | |
| 167 if (EDGE_FREQUENCY (best) * REG_BR_PROB_BASE | |
| 168 < bb->frequency * branch_ratio_cutoff) | |
| 169 return NULL; | |
| 170 return best; | |
| 171 } | |
| 172 | |
| 173 /* Find the trace using bb and record it in the TRACE array. | |
| 174 Return number of basic blocks recorded. */ | |
| 175 | |
| 176 static int | |
| 177 find_trace (basic_block bb, basic_block *trace) | |
| 178 { | |
| 179 int i = 0; | |
| 180 edge e; | |
| 181 | |
| 182 if (dump_file) | |
| 183 fprintf (dump_file, "Trace seed %i [%i]", bb->index, bb->frequency); | |
| 184 | |
| 185 while ((e = find_best_predecessor (bb)) != NULL) | |
| 186 { | |
| 187 basic_block bb2 = e->src; | |
| 188 if (bb_seen_p (bb2) || (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX)) | |
| 189 || find_best_successor (bb2) != e) | |
| 190 break; | |
| 191 if (dump_file) | |
| 192 fprintf (dump_file, ",%i [%i]", bb->index, bb->frequency); | |
| 193 bb = bb2; | |
| 194 } | |
| 195 if (dump_file) | |
| 196 fprintf (dump_file, " forward %i [%i]", bb->index, bb->frequency); | |
| 197 trace[i++] = bb; | |
| 198 | |
| 199 /* Follow the trace in forward direction. */ | |
| 200 while ((e = find_best_successor (bb)) != NULL) | |
| 201 { | |
| 202 bb = e->dest; | |
| 203 if (bb_seen_p (bb) || (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX)) | |
| 204 || find_best_predecessor (bb) != e) | |
| 205 break; | |
| 206 if (dump_file) | |
| 207 fprintf (dump_file, ",%i [%i]", bb->index, bb->frequency); | |
| 208 trace[i++] = bb; | |
| 209 } | |
| 210 if (dump_file) | |
| 211 fprintf (dump_file, "\n"); | |
| 212 return i; | |
| 213 } | |
| 214 | |
| 215 /* Look for basic blocks in frequency order, construct traces and tail duplicate | |
| 216 if profitable. */ | |
| 217 | |
| 218 static void | |
| 219 tail_duplicate (void) | |
| 220 { | |
| 221 fibnode_t *blocks = XCNEWVEC (fibnode_t, last_basic_block); | |
| 222 basic_block *trace = XNEWVEC (basic_block, n_basic_blocks); | |
| 223 int *counts = XNEWVEC (int, last_basic_block); | |
| 224 int ninsns = 0, nduplicated = 0; | |
| 225 gcov_type weighted_insns = 0, traced_insns = 0; | |
| 226 fibheap_t heap = fibheap_new (); | |
| 227 gcov_type cover_insns; | |
| 228 int max_dup_insns; | |
| 229 basic_block bb; | |
| 230 | |
| 231 /* Create an oversized sbitmap to reduce the chance that we need to | |
| 232 resize it. */ | |
| 233 bb_seen = sbitmap_alloc (last_basic_block * 2); | |
| 234 sbitmap_zero (bb_seen); | |
| 235 initialize_original_copy_tables (); | |
| 236 | |
| 237 if (profile_info && flag_branch_probabilities) | |
| 238 probability_cutoff = PARAM_VALUE (TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK); | |
| 239 else | |
| 240 probability_cutoff = PARAM_VALUE (TRACER_MIN_BRANCH_PROBABILITY); | |
| 241 probability_cutoff = REG_BR_PROB_BASE / 100 * probability_cutoff; | |
| 242 | |
| 243 branch_ratio_cutoff = | |
| 244 (REG_BR_PROB_BASE / 100 * PARAM_VALUE (TRACER_MIN_BRANCH_RATIO)); | |
| 245 | |
| 246 FOR_EACH_BB (bb) | |
| 247 { | |
| 248 int n = count_insns (bb); | |
| 249 if (!ignore_bb_p (bb)) | |
| 250 blocks[bb->index] = fibheap_insert (heap, -bb->frequency, | |
| 251 bb); | |
| 252 | |
| 253 counts [bb->index] = n; | |
| 254 ninsns += n; | |
| 255 weighted_insns += n * bb->frequency; | |
| 256 } | |
| 257 | |
| 258 if (profile_info && flag_branch_probabilities) | |
| 259 cover_insns = PARAM_VALUE (TRACER_DYNAMIC_COVERAGE_FEEDBACK); | |
| 260 else | |
| 261 cover_insns = PARAM_VALUE (TRACER_DYNAMIC_COVERAGE); | |
| 262 cover_insns = (weighted_insns * cover_insns + 50) / 100; | |
| 263 max_dup_insns = (ninsns * PARAM_VALUE (TRACER_MAX_CODE_GROWTH) + 50) / 100; | |
| 264 | |
| 265 while (traced_insns < cover_insns && nduplicated < max_dup_insns | |
| 266 && !fibheap_empty (heap)) | |
| 267 { | |
| 268 basic_block bb = (basic_block) fibheap_extract_min (heap); | |
| 269 int n, pos; | |
| 270 | |
| 271 if (!bb) | |
| 272 break; | |
| 273 | |
| 274 blocks[bb->index] = NULL; | |
| 275 | |
| 276 if (ignore_bb_p (bb)) | |
| 277 continue; | |
| 278 gcc_assert (!bb_seen_p (bb)); | |
| 279 | |
| 280 n = find_trace (bb, trace); | |
| 281 | |
| 282 bb = trace[0]; | |
| 283 traced_insns += bb->frequency * counts [bb->index]; | |
| 284 if (blocks[bb->index]) | |
| 285 { | |
| 286 fibheap_delete_node (heap, blocks[bb->index]); | |
| 287 blocks[bb->index] = NULL; | |
| 288 } | |
| 289 | |
| 290 for (pos = 1; pos < n; pos++) | |
| 291 { | |
| 292 basic_block bb2 = trace[pos]; | |
| 293 | |
| 294 if (blocks[bb2->index]) | |
| 295 { | |
| 296 fibheap_delete_node (heap, blocks[bb2->index]); | |
| 297 blocks[bb2->index] = NULL; | |
| 298 } | |
| 299 traced_insns += bb2->frequency * counts [bb2->index]; | |
| 300 if (EDGE_COUNT (bb2->preds) > 1 | |
| 301 && can_duplicate_block_p (bb2)) | |
| 302 { | |
| 303 edge e; | |
| 304 basic_block copy; | |
| 305 | |
| 306 nduplicated += counts [bb2->index]; | |
| 307 | |
| 308 e = find_edge (bb, bb2); | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
309 |
| 0 | 310 copy = duplicate_block (bb2, e, bb); |
| 311 flush_pending_stmts (e); | |
| 312 | |
| 313 add_phi_args_after_copy (©, 1, NULL); | |
| 314 | |
| 315 /* Reconsider the original copy of block we've duplicated. | |
| 316 Removing the most common predecessor may make it to be | |
| 317 head. */ | |
| 318 blocks[bb2->index] = | |
| 319 fibheap_insert (heap, -bb2->frequency, bb2); | |
| 320 | |
| 321 if (dump_file) | |
| 322 fprintf (dump_file, "Duplicated %i as %i [%i]\n", | |
| 323 bb2->index, copy->index, copy->frequency); | |
| 324 | |
| 325 bb2 = copy; | |
| 326 } | |
| 327 mark_bb_seen (bb2); | |
| 328 bb = bb2; | |
| 329 /* In case the trace became infrequent, stop duplicating. */ | |
| 330 if (ignore_bb_p (bb)) | |
| 331 break; | |
| 332 } | |
| 333 if (dump_file) | |
| 334 fprintf (dump_file, " covered now %.1f\n\n", | |
| 335 traced_insns * 100.0 / weighted_insns); | |
| 336 } | |
| 337 if (dump_file) | |
| 338 fprintf (dump_file, "Duplicated %i insns (%i%%)\n", nduplicated, | |
| 339 nduplicated * 100 / ninsns); | |
| 340 | |
| 341 free_original_copy_tables (); | |
| 342 sbitmap_free (bb_seen); | |
| 343 free (blocks); | |
| 344 free (trace); | |
| 345 free (counts); | |
| 346 fibheap_delete (heap); | |
| 347 } | |
| 348 | |
| 349 /* Main entry point to this file. */ | |
| 350 | |
| 351 static unsigned int | |
| 352 tracer (void) | |
| 353 { | |
| 354 gcc_assert (current_ir_type () == IR_GIMPLE); | |
| 355 | |
| 356 if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1) | |
| 357 return 0; | |
| 358 | |
| 359 mark_dfs_back_edges (); | |
| 360 if (dump_file) | |
| 361 dump_flow_info (dump_file, dump_flags); | |
| 362 | |
| 363 /* Trace formation is done on the fly inside tail_duplicate */ | |
| 364 tail_duplicate (); | |
| 365 | |
| 366 /* FIXME: We really only need to do this when we know tail duplication | |
| 367 has altered the CFG. */ | |
| 368 free_dominance_info (CDI_DOMINATORS); | |
| 369 if (dump_file) | |
| 370 dump_flow_info (dump_file, dump_flags); | |
| 371 | |
| 372 return 0; | |
| 373 } | |
| 374 | |
| 375 static bool | |
| 376 gate_tracer (void) | |
| 377 { | |
| 378 return (optimize > 0 && flag_tracer && flag_reorder_blocks); | |
| 379 } | |
| 380 | |
| 381 struct gimple_opt_pass pass_tracer = | |
| 382 { | |
| 383 { | |
| 384 GIMPLE_PASS, | |
| 385 "tracer", /* name */ | |
| 386 gate_tracer, /* gate */ | |
| 387 tracer, /* execute */ | |
| 388 NULL, /* sub */ | |
| 389 NULL, /* next */ | |
| 390 0, /* static_pass_number */ | |
| 391 TV_TRACER, /* tv_id */ | |
| 392 0, /* properties_required */ | |
| 393 0, /* properties_provided */ | |
| 394 0, /* properties_destroyed */ | |
| 395 0, /* todo_flags_start */ | |
| 396 TODO_dump_func | |
| 397 | TODO_update_ssa | |
| 398 | TODO_verify_ssa /* todo_flags_finish */ | |
| 399 } | |
| 400 }; |