1 /* Generic routines for manipulating SSA_NAME expressions 2 Copyright (C) 2003-2018 Free Software Foundation, Inc. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 GCC is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GCC; see the file COPYING3. If not see 18 <http://www.gnu.org/licenses/>. */ 19 20 #include "config.h" 21 #include "system.h" 22 #include "coretypes.h" 23 #include "backend.h" 24 #include "tree.h" 25 #include "gimple.h" 26 #include "tree-pass.h" 27 #include "ssa.h" 28 #include "gimple-iterator.h" 29 #include "stor-layout.h" 30 #include "tree-into-ssa.h" 31 #include "tree-ssa.h" 32 #include "cfgloop.h" 33 #include "tree-scalar-evolution.h" 34 35 /* Rewriting a function into SSA form can create a huge number of SSA_NAMEs, 36 many of which may be thrown away shortly after their creation if jumps 37 were threaded through PHI nodes. 38 39 While our garbage collection mechanisms will handle this situation, it 40 is extremely wasteful to create nodes and throw them away, especially 41 when the nodes can be reused. 42 43 For PR 8361, we can significantly reduce the number of nodes allocated 44 and thus the total amount of memory allocated by managing SSA_NAMEs a 45 little. This additionally helps reduce the amount of work done by the 46 garbage collector. Similar results have been seen on a wider variety 47 of tests (such as the compiler itself). 48 49 Right now we maintain our free list on a per-function basis. It may 50 or may not make sense to maintain the free list for the duration of 51 a compilation unit. 52 53 External code should rely solely upon HIGHEST_SSA_VERSION and the 54 externally defined functions. External code should not know about 55 the details of the free list management. 56 57 External code should also not assume the version number on nodes is 58 monotonically increasing. We reuse the version number when we 59 reuse an SSA_NAME expression. This helps keep arrays and bitmaps 60 more compact. */ 61 62 63 /* Version numbers with special meanings. We start allocating new version 64 numbers after the special ones. */ 65 #define UNUSED_NAME_VERSION 0 66 67 unsigned int ssa_name_nodes_reused; 68 unsigned int ssa_name_nodes_created; 69 70 #define FREE_SSANAMES(fun) (fun)->gimple_df->free_ssanames 71 #define FREE_SSANAMES_QUEUE(fun) (fun)->gimple_df->free_ssanames_queue 72 73 74 /* Initialize management of SSA_NAMEs to default SIZE. If SIZE is 75 zero use default. */ 76 77 void 78 init_ssanames (struct function *fn, int size) 79 { 80 if (size < 50) 81 size = 50; 82 83 vec_alloc (SSANAMES (fn), size); 84 85 /* Version 0 is special, so reserve the first slot in the table. Though 86 currently unused, we may use version 0 in alias analysis as part of 87 the heuristics used to group aliases when the alias sets are too 88 large. 89 90 We use vec::quick_push here because we know that SSA_NAMES has at 91 least 50 elements reserved in it. */ 92 SSANAMES (fn)->quick_push (NULL_TREE); 93 FREE_SSANAMES (fn) = NULL; 94 FREE_SSANAMES_QUEUE (fn) = NULL; 95 96 fn->gimple_df->ssa_renaming_needed = 0; 97 fn->gimple_df->rename_vops = 0; 98 } 99 100 /* Finalize management of SSA_NAMEs. */ 101 102 void 103 fini_ssanames (struct function *fn) 104 { 105 vec_free (SSANAMES (fn)); 106 vec_free (FREE_SSANAMES (fn)); 107 vec_free (FREE_SSANAMES_QUEUE (fn)); 108 } 109 110 /* Dump some simple statistics regarding the re-use of SSA_NAME nodes. */ 111 112 void 113 ssanames_print_statistics (void) 114 { 115 fprintf (stderr, "SSA_NAME nodes allocated: %u\n", ssa_name_nodes_created); 116 fprintf (stderr, "SSA_NAME nodes reused: %u\n", ssa_name_nodes_reused); 117 } 118 119 /* Verify the state of the SSA_NAME lists. 120 121 There must be no duplicates on the free list. 122 Every name on the free list must be marked as on the free list. 123 Any name on the free list must not appear in the IL. 124 No names can be leaked. */ 125 126 DEBUG_FUNCTION void 127 verify_ssaname_freelists (struct function *fun) 128 { 129 if (!gimple_in_ssa_p (fun)) 130 return; 131 132 auto_bitmap names_in_il; 133 134 /* Walk the entire IL noting every SSA_NAME we see. */ 135 basic_block bb; 136 FOR_EACH_BB_FN (bb, fun) 137 { 138 tree t; 139 /* First note the result and arguments of PHI nodes. */ 140 for (gphi_iterator gsi = gsi_start_phis (bb); 141 !gsi_end_p (gsi); 142 gsi_next (&gsi)) 143 { 144 gphi *phi = gsi.phi (); 145 t = gimple_phi_result (phi); 146 bitmap_set_bit (names_in_il, SSA_NAME_VERSION (t)); 147 148 for (unsigned int i = 0; i < gimple_phi_num_args (phi); i++) 149 { 150 t = gimple_phi_arg_def (phi, i); 151 if (TREE_CODE (t) == SSA_NAME) 152 bitmap_set_bit (names_in_il, SSA_NAME_VERSION (t)); 153 } 154 } 155 156 /* Then note the operands of each statement. */ 157 for (gimple_stmt_iterator gsi = gsi_start_bb (bb); 158 !gsi_end_p (gsi); 159 gsi_next (&gsi)) 160 { 161 ssa_op_iter iter; 162 gimple *stmt = gsi_stmt (gsi); 163 FOR_EACH_SSA_TREE_OPERAND (t, stmt, iter, SSA_OP_ALL_OPERANDS) 164 bitmap_set_bit (names_in_il, SSA_NAME_VERSION (t)); 165 } 166 } 167 168 /* Now walk the free list noting what we find there and verifying 169 there are no duplicates. */ 170 auto_bitmap names_in_freelists; 171 if (FREE_SSANAMES (fun)) 172 { 173 for (unsigned int i = 0; i < FREE_SSANAMES (fun)->length (); i++) 174 { 175 tree t = (*FREE_SSANAMES (fun))[i]; 176 177 /* Verify that the name is marked as being in the free list. */ 178 gcc_assert (SSA_NAME_IN_FREE_LIST (t)); 179 180 /* Verify the name has not already appeared in the free list and 181 note it in the list of names found in the free list. */ 182 gcc_assert (!bitmap_bit_p (names_in_freelists, SSA_NAME_VERSION (t))); 183 bitmap_set_bit (names_in_freelists, SSA_NAME_VERSION (t)); 184 } 185 } 186 187 /* Similarly for the names in the pending free list. */ 188 if (FREE_SSANAMES_QUEUE (fun)) 189 { 190 for (unsigned int i = 0; i < FREE_SSANAMES_QUEUE (fun)->length (); i++) 191 { 192 tree t = (*FREE_SSANAMES_QUEUE (fun))[i]; 193 194 /* Verify that the name is marked as being in the free list. */ 195 gcc_assert (SSA_NAME_IN_FREE_LIST (t)); 196 197 /* Verify the name has not already appeared in the free list and 198 note it in the list of names found in the free list. */ 199 gcc_assert (!bitmap_bit_p (names_in_freelists, SSA_NAME_VERSION (t))); 200 bitmap_set_bit (names_in_freelists, SSA_NAME_VERSION (t)); 201 } 202 } 203 204 /* If any name appears in both the IL and the freelists, then 205 something horrible has happened. */ 206 bool intersect_p = bitmap_intersect_p (names_in_il, names_in_freelists); 207 gcc_assert (!intersect_p); 208 209 /* Names can be queued up for release if there is an ssa update 210 pending. Pretend we saw them in the IL. */ 211 if (names_to_release) 212 bitmap_ior_into (names_in_il, names_to_release); 213 214 /* Function splitting can "lose" SSA_NAMEs in an effort to ensure that 215 debug/non-debug compilations have the same SSA_NAMEs. So for each 216 lost SSA_NAME, see if it's likely one from that wart. These will always 217 be marked as default definitions. So we loosely assume that anything 218 marked as a default definition isn't leaked by pretending they are 219 in the IL. */ 220 for (unsigned int i = UNUSED_NAME_VERSION + 1; i < num_ssa_names; i++) 221 if (ssa_name (i) && SSA_NAME_IS_DEFAULT_DEF (ssa_name (i))) 222 bitmap_set_bit (names_in_il, i); 223 224 unsigned int i; 225 bitmap_iterator bi; 226 auto_bitmap all_names; 227 bitmap_set_range (all_names, UNUSED_NAME_VERSION + 1, num_ssa_names - 1); 228 bitmap_ior_into (names_in_il, names_in_freelists); 229 230 /* Any name not mentioned in the IL and not in the feelists 231 has been leaked. */ 232 EXECUTE_IF_AND_COMPL_IN_BITMAP(all_names, names_in_il, 233 UNUSED_NAME_VERSION + 1, i, bi) 234 gcc_assert (!ssa_name (i)); 235 } 236 237 /* Move all SSA_NAMEs from FREE_SSA_NAMES_QUEUE to FREE_SSA_NAMES. 238 239 We do not, but should have a mode to verify the state of the SSA_NAMEs 240 lists. In particular at this point every name must be in the IL, 241 on the free list or in the queue. Anything else is an error. */ 242 243 void 244 flush_ssaname_freelist (void) 245 { 246 /* If there were any SSA names released reset the SCEV cache. */ 247 if (! vec_safe_is_empty (FREE_SSANAMES_QUEUE (cfun))) 248 scev_reset_htab (); 249 vec_safe_splice (FREE_SSANAMES (cfun), FREE_SSANAMES_QUEUE (cfun)); 250 vec_safe_truncate (FREE_SSANAMES_QUEUE (cfun), 0); 251 } 252 253 /* Return an SSA_NAME node for variable VAR defined in statement STMT 254 in function FN. STMT may be an empty statement for artificial 255 references (e.g., default definitions created when a variable is 256 used without a preceding definition). If VERISON is not zero then 257 allocate the SSA name with that version. */ 258 259 tree 260 make_ssa_name_fn (struct function *fn, tree var, gimple *stmt, 261 unsigned int version) 262 { 263 tree t; 264 use_operand_p imm; 265 266 gcc_assert (VAR_P (var) 267 || TREE_CODE (var) == PARM_DECL 268 || TREE_CODE (var) == RESULT_DECL 269 || (TYPE_P (var) && is_gimple_reg_type (var))); 270 271 /* Get the specified SSA name version. */ 272 if (version != 0) 273 { 274 t = make_node (SSA_NAME); 275 SSA_NAME_VERSION (t) = version; 276 if (version >= SSANAMES (fn)->length ()) 277 vec_safe_grow_cleared (SSANAMES (fn), version + 1); 278 gcc_assert ((*SSANAMES (fn))[version] == NULL); 279 (*SSANAMES (fn))[version] = t; 280 ssa_name_nodes_created++; 281 } 282 /* If our free list has an element, then use it. */ 283 else if (!vec_safe_is_empty (FREE_SSANAMES (fn))) 284 { 285 t = FREE_SSANAMES (fn)->pop (); 286 ssa_name_nodes_reused++; 287 288 /* The node was cleared out when we put it on the free list, so 289 there is no need to do so again here. */ 290 gcc_assert ((*SSANAMES (fn))[SSA_NAME_VERSION (t)] == NULL); 291 (*SSANAMES (fn))[SSA_NAME_VERSION (t)] = t; 292 } 293 else 294 { 295 t = make_node (SSA_NAME); 296 SSA_NAME_VERSION (t) = SSANAMES (fn)->length (); 297 vec_safe_push (SSANAMES (fn), t); 298 ssa_name_nodes_created++; 299 } 300 301 if (TYPE_P (var)) 302 { 303 TREE_TYPE (t) = TYPE_MAIN_VARIANT (var); 304 SET_SSA_NAME_VAR_OR_IDENTIFIER (t, NULL_TREE); 305 } 306 else 307 { 308 TREE_TYPE (t) = TREE_TYPE (var); 309 SET_SSA_NAME_VAR_OR_IDENTIFIER (t, var); 310 } 311 SSA_NAME_DEF_STMT (t) = stmt; 312 if (POINTER_TYPE_P (TREE_TYPE (t))) 313 SSA_NAME_PTR_INFO (t) = NULL; 314 else 315 SSA_NAME_RANGE_INFO (t) = NULL; 316 317 SSA_NAME_IN_FREE_LIST (t) = 0; 318 SSA_NAME_IS_DEFAULT_DEF (t) = 0; 319 imm = &(SSA_NAME_IMM_USE_NODE (t)); 320 imm->use = NULL; 321 imm->prev = imm; 322 imm->next = imm; 323 imm->loc.ssa_name = t; 324 325 return t; 326 } 327 328 /* Helper function for set_range_info. 329 330 Store range information RANGE_TYPE, MIN, and MAX to tree ssa_name 331 NAME. */ 332 333 void 334 set_range_info_raw (tree name, enum value_range_type range_type, 335 const wide_int_ref &min, const wide_int_ref &max) 336 { 337 gcc_assert (!POINTER_TYPE_P (TREE_TYPE (name))); 338 gcc_assert (range_type == VR_RANGE || range_type == VR_ANTI_RANGE); 339 range_info_def *ri = SSA_NAME_RANGE_INFO (name); 340 unsigned int precision = TYPE_PRECISION (TREE_TYPE (name)); 341 342 /* Allocate if not available. */ 343 if (ri == NULL) 344 { 345 size_t size = (sizeof (range_info_def) 346 + trailing_wide_ints <3>::extra_size (precision)); 347 ri = static_cast<range_info_def *> (ggc_internal_alloc (size)); 348 ri->ints.set_precision (precision); 349 SSA_NAME_RANGE_INFO (name) = ri; 350 ri->set_nonzero_bits (wi::shwi (-1, precision)); 351 } 352 353 /* Record the range type. */ 354 if (SSA_NAME_RANGE_TYPE (name) != range_type) 355 SSA_NAME_ANTI_RANGE_P (name) = (range_type == VR_ANTI_RANGE); 356 357 /* Set the values. */ 358 ri->set_min (min); 359 ri->set_max (max); 360 361 /* If it is a range, try to improve nonzero_bits from the min/max. */ 362 if (range_type == VR_RANGE) 363 { 364 wide_int xorv = ri->get_min () ^ ri->get_max (); 365 if (xorv != 0) 366 xorv = wi::mask (precision - wi::clz (xorv), false, precision); 367 ri->set_nonzero_bits (ri->get_nonzero_bits () & (ri->get_min () | xorv)); 368 } 369 } 370 371 /* Store range information RANGE_TYPE, MIN, and MAX to tree ssa_name 372 NAME while making sure we don't store useless range info. */ 373 374 void 375 set_range_info (tree name, enum value_range_type range_type, 376 const wide_int_ref &min, const wide_int_ref &max) 377 { 378 gcc_assert (!POINTER_TYPE_P (TREE_TYPE (name))); 379 380 /* A range of the entire domain is really no range at all. */ 381 tree type = TREE_TYPE (name); 382 if (min == wi::min_value (TYPE_PRECISION (type), TYPE_SIGN (type)) 383 && max == wi::max_value (TYPE_PRECISION (type), TYPE_SIGN (type))) 384 { 385 range_info_def *ri = SSA_NAME_RANGE_INFO (name); 386 if (ri == NULL) 387 return; 388 if (ri->get_nonzero_bits () == -1) 389 { 390 ggc_free (ri); 391 SSA_NAME_RANGE_INFO (name) = NULL; 392 return; 393 } 394 } 395 396 set_range_info_raw (name, range_type, min, max); 397 } 398 399 400 /* Gets range information MIN, MAX and returns enum value_range_type 401 corresponding to tree ssa_name NAME. enum value_range_type returned 402 is used to determine if MIN and MAX are valid values. */ 403 404 enum value_range_type 405 get_range_info (const_tree name, wide_int *min, wide_int *max) 406 { 407 gcc_assert (!POINTER_TYPE_P (TREE_TYPE (name))); 408 gcc_assert (min && max); 409 range_info_def *ri = SSA_NAME_RANGE_INFO (name); 410 411 /* Return VR_VARYING for SSA_NAMEs with NULL RANGE_INFO or SSA_NAMEs 412 with integral types width > 2 * HOST_BITS_PER_WIDE_INT precision. */ 413 if (!ri || (GET_MODE_PRECISION (SCALAR_INT_TYPE_MODE (TREE_TYPE (name))) 414 > 2 * HOST_BITS_PER_WIDE_INT)) 415 return VR_VARYING; 416 417 *min = ri->get_min (); 418 *max = ri->get_max (); 419 return SSA_NAME_RANGE_TYPE (name); 420 } 421 422 /* Set nonnull attribute to pointer NAME. */ 423 424 void 425 set_ptr_nonnull (tree name) 426 { 427 gcc_assert (POINTER_TYPE_P (TREE_TYPE (name))); 428 struct ptr_info_def *pi = get_ptr_info (name); 429 pi->pt.null = 0; 430 } 431 432 /* Return nonnull attribute of pointer NAME. */ 433 bool 434 get_ptr_nonnull (const_tree name) 435 { 436 gcc_assert (POINTER_TYPE_P (TREE_TYPE (name))); 437 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (name); 438 if (pi == NULL) 439 return false; 440 /* TODO Now pt->null is conservatively set to true in PTA 441 analysis. vrp is the only pass (including ipa-vrp) 442 that clears pt.null via set_ptr_nonull when it knows 443 for sure. PTA will preserves the pt.null value set by VRP. 444 445 When PTA analysis is improved, pt.anything, pt.nonlocal 446 and pt.escaped may also has to be considered before 447 deciding that pointer cannot point to NULL. */ 448 return !pi->pt.null; 449 } 450 451 /* Change non-zero bits bitmask of NAME. */ 452 453 void 454 set_nonzero_bits (tree name, const wide_int_ref &mask) 455 { 456 gcc_assert (!POINTER_TYPE_P (TREE_TYPE (name))); 457 if (SSA_NAME_RANGE_INFO (name) == NULL) 458 { 459 if (mask == -1) 460 return; 461 set_range_info_raw (name, VR_RANGE, 462 wi::to_wide (TYPE_MIN_VALUE (TREE_TYPE (name))), 463 wi::to_wide (TYPE_MAX_VALUE (TREE_TYPE (name)))); 464 } 465 range_info_def *ri = SSA_NAME_RANGE_INFO (name); 466 ri->set_nonzero_bits (mask); 467 } 468 469 /* Return a widest_int with potentially non-zero bits in SSA_NAME 470 NAME, the constant for INTEGER_CST, or -1 if unknown. */ 471 472 wide_int 473 get_nonzero_bits (const_tree name) 474 { 475 if (TREE_CODE (name) == INTEGER_CST) 476 return wi::to_wide (name); 477 478 /* Use element_precision instead of TYPE_PRECISION so complex and 479 vector types get a non-zero precision. */ 480 unsigned int precision = element_precision (TREE_TYPE (name)); 481 if (POINTER_TYPE_P (TREE_TYPE (name))) 482 { 483 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (name); 484 if (pi && pi->align) 485 return wi::shwi (-(HOST_WIDE_INT) pi->align 486 | (HOST_WIDE_INT) pi->misalign, precision); 487 return wi::shwi (-1, precision); 488 } 489 490 range_info_def *ri = SSA_NAME_RANGE_INFO (name); 491 if (!ri) 492 return wi::shwi (-1, precision); 493 494 return ri->get_nonzero_bits (); 495 } 496 497 /* Return TRUE is OP, an SSA_NAME has a range of values [0..1], false 498 otherwise. 499 500 This can be because it is a boolean type, any unsigned integral 501 type with a single bit of precision, or has known range of [0..1] 502 via VRP analysis. */ 503 504 bool 505 ssa_name_has_boolean_range (tree op) 506 { 507 gcc_assert (TREE_CODE (op) == SSA_NAME); 508 509 /* Boolean types always have a range [0..1]. */ 510 if (TREE_CODE (TREE_TYPE (op)) == BOOLEAN_TYPE) 511 return true; 512 513 /* An integral type with a single bit of precision. */ 514 if (INTEGRAL_TYPE_P (TREE_TYPE (op)) 515 && TYPE_UNSIGNED (TREE_TYPE (op)) 516 && TYPE_PRECISION (TREE_TYPE (op)) == 1) 517 return true; 518 519 /* An integral type with more precision, but the object 520 only takes on values [0..1] as determined by VRP 521 analysis. */ 522 if (INTEGRAL_TYPE_P (TREE_TYPE (op)) 523 && (TYPE_PRECISION (TREE_TYPE (op)) > 1) 524 && wi::eq_p (get_nonzero_bits (op), 1)) 525 return true; 526 527 return false; 528 } 529 530 /* We no longer need the SSA_NAME expression VAR, release it so that 531 it may be reused. 532 533 Note it is assumed that no calls to make_ssa_name will be made 534 until all uses of the ssa name are released and that the only 535 use of the SSA_NAME expression is to check its SSA_NAME_VAR. All 536 other fields must be assumed clobbered. */ 537 538 void 539 release_ssa_name_fn (struct function *fn, tree var) 540 { 541 if (!var) 542 return; 543 544 /* Never release the default definition for a symbol. It's a 545 special SSA name that should always exist once it's created. */ 546 if (SSA_NAME_IS_DEFAULT_DEF (var)) 547 return; 548 549 /* If VAR has been registered for SSA updating, don't remove it. 550 After update_ssa has run, the name will be released. */ 551 if (name_registered_for_update_p (var)) 552 { 553 release_ssa_name_after_update_ssa (var); 554 return; 555 } 556 557 /* release_ssa_name can be called multiple times on a single SSA_NAME. 558 However, it should only end up on our free list one time. We 559 keep a status bit in the SSA_NAME node itself to indicate it has 560 been put on the free list. 561 562 Note that once on the freelist you can not reference the SSA_NAME's 563 defining statement. */ 564 if (! SSA_NAME_IN_FREE_LIST (var)) 565 { 566 tree saved_ssa_name_var = SSA_NAME_VAR (var); 567 int saved_ssa_name_version = SSA_NAME_VERSION (var); 568 use_operand_p imm = &(SSA_NAME_IMM_USE_NODE (var)); 569 570 if (MAY_HAVE_DEBUG_BIND_STMTS) 571 insert_debug_temp_for_var_def (NULL, var); 572 573 if (flag_checking) 574 verify_imm_links (stderr, var); 575 while (imm->next != imm) 576 delink_imm_use (imm->next); 577 578 (*SSANAMES (fn))[SSA_NAME_VERSION (var)] = NULL_TREE; 579 memset (var, 0, tree_size (var)); 580 581 imm->prev = imm; 582 imm->next = imm; 583 imm->loc.ssa_name = var; 584 585 /* First put back the right tree node so that the tree checking 586 macros do not complain. */ 587 TREE_SET_CODE (var, SSA_NAME); 588 589 /* Restore the version number. */ 590 SSA_NAME_VERSION (var) = saved_ssa_name_version; 591 592 /* Hopefully this can go away once we have the new incremental 593 SSA updating code installed. */ 594 SET_SSA_NAME_VAR_OR_IDENTIFIER (var, saved_ssa_name_var); 595 596 /* Note this SSA_NAME is now in the first list. */ 597 SSA_NAME_IN_FREE_LIST (var) = 1; 598 599 /* And finally queue it so that it will be put on the free list. */ 600 vec_safe_push (FREE_SSANAMES_QUEUE (fn), var); 601 } 602 } 603 604 /* If the alignment of the pointer described by PI is known, return true and 605 store the alignment and the deviation from it into *ALIGNP and *MISALIGNP 606 respectively. Otherwise return false. */ 607 608 bool 609 get_ptr_info_alignment (struct ptr_info_def *pi, unsigned int *alignp, 610 unsigned int *misalignp) 611 { 612 if (pi->align) 613 { 614 *alignp = pi->align; 615 *misalignp = pi->misalign; 616 return true; 617 } 618 else 619 return false; 620 } 621 622 /* State that the pointer described by PI has unknown alignment. */ 623 624 void 625 mark_ptr_info_alignment_unknown (struct ptr_info_def *pi) 626 { 627 pi->align = 0; 628 pi->misalign = 0; 629 } 630 631 /* Store the power-of-two byte alignment and the deviation from that 632 alignment of pointer described by PI to ALIOGN and MISALIGN 633 respectively. */ 634 635 void 636 set_ptr_info_alignment (struct ptr_info_def *pi, unsigned int align, 637 unsigned int misalign) 638 { 639 gcc_checking_assert (align != 0); 640 gcc_assert ((align & (align - 1)) == 0); 641 gcc_assert ((misalign & ~(align - 1)) == 0); 642 643 pi->align = align; 644 pi->misalign = misalign; 645 } 646 647 /* If pointer described by PI has known alignment, increase its known 648 misalignment by INCREMENT modulo its current alignment. */ 649 650 void 651 adjust_ptr_info_misalignment (struct ptr_info_def *pi, poly_uint64 increment) 652 { 653 if (pi->align != 0) 654 { 655 increment += pi->misalign; 656 if (!known_misalignment (increment, pi->align, &pi->misalign)) 657 { 658 pi->align = known_alignment (increment); 659 pi->misalign = 0; 660 } 661 } 662 } 663 664 /* Return the alias information associated with pointer T. It creates a 665 new instance if none existed. */ 666 667 struct ptr_info_def * 668 get_ptr_info (tree t) 669 { 670 struct ptr_info_def *pi; 671 672 gcc_assert (POINTER_TYPE_P (TREE_TYPE (t))); 673 674 pi = SSA_NAME_PTR_INFO (t); 675 if (pi == NULL) 676 { 677 pi = ggc_cleared_alloc<ptr_info_def> (); 678 pt_solution_reset (&pi->pt); 679 mark_ptr_info_alignment_unknown (pi); 680 SSA_NAME_PTR_INFO (t) = pi; 681 } 682 683 return pi; 684 } 685 686 687 /* Creates a new SSA name using the template NAME tobe defined by 688 statement STMT in function FN. */ 689 690 tree 691 copy_ssa_name_fn (struct function *fn, tree name, gimple *stmt) 692 { 693 tree new_name; 694 695 if (SSA_NAME_VAR (name)) 696 new_name = make_ssa_name_fn (fn, SSA_NAME_VAR (name), stmt); 697 else 698 { 699 new_name = make_ssa_name_fn (fn, TREE_TYPE (name), stmt); 700 SET_SSA_NAME_VAR_OR_IDENTIFIER (new_name, SSA_NAME_IDENTIFIER (name)); 701 } 702 703 return new_name; 704 } 705 706 707 /* Creates a duplicate of the ptr_info_def at PTR_INFO for use by 708 the SSA name NAME. */ 709 710 void 711 duplicate_ssa_name_ptr_info (tree name, struct ptr_info_def *ptr_info) 712 { 713 struct ptr_info_def *new_ptr_info; 714 715 gcc_assert (POINTER_TYPE_P (TREE_TYPE (name))); 716 gcc_assert (!SSA_NAME_PTR_INFO (name)); 717 718 if (!ptr_info) 719 return; 720 721 new_ptr_info = ggc_alloc<ptr_info_def> (); 722 *new_ptr_info = *ptr_info; 723 724 SSA_NAME_PTR_INFO (name) = new_ptr_info; 725 } 726 727 /* Creates a duplicate of the range_info_def at RANGE_INFO of type 728 RANGE_TYPE for use by the SSA name NAME. */ 729 void 730 duplicate_ssa_name_range_info (tree name, enum value_range_type range_type, 731 struct range_info_def *range_info) 732 { 733 struct range_info_def *new_range_info; 734 735 gcc_assert (!POINTER_TYPE_P (TREE_TYPE (name))); 736 gcc_assert (!SSA_NAME_RANGE_INFO (name)); 737 738 if (!range_info) 739 return; 740 741 unsigned int precision = TYPE_PRECISION (TREE_TYPE (name)); 742 size_t size = (sizeof (range_info_def) 743 + trailing_wide_ints <3>::extra_size (precision)); 744 new_range_info = static_cast<range_info_def *> (ggc_internal_alloc (size)); 745 memcpy (new_range_info, range_info, size); 746 747 gcc_assert (range_type == VR_RANGE || range_type == VR_ANTI_RANGE); 748 SSA_NAME_ANTI_RANGE_P (name) = (range_type == VR_ANTI_RANGE); 749 SSA_NAME_RANGE_INFO (name) = new_range_info; 750 } 751 752 753 754 /* Creates a duplicate of a ssa name NAME tobe defined by statement STMT 755 in function FN. */ 756 757 tree 758 duplicate_ssa_name_fn (struct function *fn, tree name, gimple *stmt) 759 { 760 tree new_name = copy_ssa_name_fn (fn, name, stmt); 761 if (POINTER_TYPE_P (TREE_TYPE (name))) 762 { 763 struct ptr_info_def *old_ptr_info = SSA_NAME_PTR_INFO (name); 764 765 if (old_ptr_info) 766 duplicate_ssa_name_ptr_info (new_name, old_ptr_info); 767 } 768 else 769 { 770 struct range_info_def *old_range_info = SSA_NAME_RANGE_INFO (name); 771 772 if (old_range_info) 773 duplicate_ssa_name_range_info (new_name, SSA_NAME_RANGE_TYPE (name), 774 old_range_info); 775 } 776 777 return new_name; 778 } 779 780 781 /* Reset all flow sensitive data on NAME such as range-info, nonzero 782 bits and alignment. */ 783 784 void 785 reset_flow_sensitive_info (tree name) 786 { 787 if (POINTER_TYPE_P (TREE_TYPE (name))) 788 { 789 /* points-to info is not flow-sensitive. */ 790 if (SSA_NAME_PTR_INFO (name)) 791 mark_ptr_info_alignment_unknown (SSA_NAME_PTR_INFO (name)); 792 } 793 else 794 SSA_NAME_RANGE_INFO (name) = NULL; 795 } 796 797 /* Clear all flow sensitive data from all statements and PHI definitions 798 in BB. */ 799 800 void 801 reset_flow_sensitive_info_in_bb (basic_block bb) 802 { 803 for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); 804 gsi_next (&gsi)) 805 { 806 gimple *stmt = gsi_stmt (gsi); 807 ssa_op_iter i; 808 tree op; 809 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_DEF) 810 reset_flow_sensitive_info (op); 811 } 812 813 for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); 814 gsi_next (&gsi)) 815 { 816 tree phi_def = gimple_phi_result (gsi.phi ()); 817 reset_flow_sensitive_info (phi_def); 818 } 819 } 820 821 /* Release all the SSA_NAMEs created by STMT. */ 822 823 void 824 release_defs (gimple *stmt) 825 { 826 tree def; 827 ssa_op_iter iter; 828 829 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) 830 if (TREE_CODE (def) == SSA_NAME) 831 release_ssa_name (def); 832 } 833 834 835 /* Replace the symbol associated with SSA_NAME with SYM. */ 836 837 void 838 replace_ssa_name_symbol (tree ssa_name, tree sym) 839 { 840 SET_SSA_NAME_VAR_OR_IDENTIFIER (ssa_name, sym); 841 TREE_TYPE (ssa_name) = TREE_TYPE (sym); 842 } 843 844 /* Release the vector of free SSA_NAMEs and compact the vector of SSA_NAMEs 845 that are live. */ 846 847 static void 848 release_free_names_and_compact_live_names (function *fun) 849 { 850 unsigned i, j; 851 int n = vec_safe_length (FREE_SSANAMES (fun)); 852 853 /* Now release the freelist. */ 854 vec_free (FREE_SSANAMES (fun)); 855 856 /* And compact the SSA number space. We make sure to not change the 857 relative order of SSA versions. */ 858 for (i = 1, j = 1; i < fun->gimple_df->ssa_names->length (); ++i) 859 { 860 tree name = ssa_name (i); 861 if (name) 862 { 863 if (i != j) 864 { 865 SSA_NAME_VERSION (name) = j; 866 (*fun->gimple_df->ssa_names)[j] = name; 867 } 868 j++; 869 } 870 } 871 fun->gimple_df->ssa_names->truncate (j); 872 873 statistics_counter_event (fun, "SSA names released", n); 874 statistics_counter_event (fun, "SSA name holes removed", i - j); 875 if (dump_file) 876 fprintf (dump_file, "Released %i names, %.2f%%, removed %i holes\n", 877 n, n * 100.0 / num_ssa_names, i - j); 878 } 879 880 /* Return SSA names that are unused to GGC memory and compact the SSA 881 version namespace. This is used to keep footprint of compiler during 882 interprocedural optimization. */ 883 884 namespace { 885 886 const pass_data pass_data_release_ssa_names = 887 { 888 GIMPLE_PASS, /* type */ 889 "release_ssa", /* name */ 890 OPTGROUP_NONE, /* optinfo_flags */ 891 TV_TREE_SSA_OTHER, /* tv_id */ 892 PROP_ssa, /* properties_required */ 893 0, /* properties_provided */ 894 0, /* properties_destroyed */ 895 TODO_remove_unused_locals, /* todo_flags_start */ 896 0, /* todo_flags_finish */ 897 }; 898 899 class pass_release_ssa_names : public gimple_opt_pass 900 { 901 public: 902 pass_release_ssa_names (gcc::context *ctxt) 903 : gimple_opt_pass (pass_data_release_ssa_names, ctxt) 904 {} 905 906 /* opt_pass methods: */ 907 virtual unsigned int execute (function *); 908 909 }; // class pass_release_ssa_names 910 911 unsigned int 912 pass_release_ssa_names::execute (function *fun) 913 { 914 release_free_names_and_compact_live_names (fun); 915 return 0; 916 } 917 918 } // anon namespace 919 920 gimple_opt_pass * 921 make_pass_release_ssa_names (gcc::context *ctxt) 922 { 923 return new pass_release_ssa_names (ctxt); 924 } 925