gcc/tree-dfa.c

   1 /* Data flow functions for trees.
   2    Copyright (C) 2001-2017 Free Software Foundation, Inc.
   3    Contributed by Diego Novillo <dnovillo@redhat.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "backend.h"
  25 #include "rtl.h"
  26 #include "tree.h"
  27 #include "gimple.h"
  28 #include "tree-pass.h"
  29 #include "ssa.h"
  30 #include "tree-pretty-print.h"
  31 #include "fold-const.h"
  32 #include "stor-layout.h"
  33 #include "langhooks.h"
  34 #include "gimple-iterator.h"
  35 #include "gimple-walk.h"
  36 #include "tree-dfa.h"
  37
  38 /* Build and maintain data flow information for trees.  */
  39
  40 /* Counters used to display DFA and SSA statistics.  */
  41 struct dfa_stats_d
  42 {
  43   long num_defs;
  44   long num_uses;
  45   long num_phis;
  46   long num_phi_args;
  47   size_t max_num_phi_args;
  48   long num_vdefs;
  49   long num_vuses;
  50 };
  51
  52
  53 /* Local functions.  */
  54 static void collect_dfa_stats (struct dfa_stats_d *);
  55
  56
  57 /*---------------------------------------------------------------------------
  58                         Dataflow analysis (DFA) routines
  59 ---------------------------------------------------------------------------*/
  60
  61 /* Renumber all of the gimple stmt uids.  */
  62
  63 void
  64 renumber_gimple_stmt_uids (void)
  65 {
  66   basic_block bb;
  67
  68   set_gimple_stmt_max_uid (cfun, 0);
  69   FOR_ALL_BB_FN (bb, cfun)
  70     {
  71       gimple_stmt_iterator bsi;
  72       for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
  73         {
  74           gimple *stmt = gsi_stmt (bsi);
  75           gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
  76         }
  77       for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
  78         {
  79           gimple *stmt = gsi_stmt (bsi);
  80           gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
  81         }
  82     }
  83 }
  84
  85 /* Like renumber_gimple_stmt_uids, but only do work on the basic blocks
  86    in BLOCKS, of which there are N_BLOCKS.  Also renumbers PHIs.  */
  87
  88 void
  89 renumber_gimple_stmt_uids_in_blocks (basic_block *blocks, int n_blocks)
  90 {
  91   int i;
  92
  93   set_gimple_stmt_max_uid (cfun, 0);
  94   for (i = 0; i < n_blocks; i++)
  95     {
  96       basic_block bb = blocks[i];
  97       gimple_stmt_iterator bsi;
  98       for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
  99         {
 100           gimple *stmt = gsi_stmt (bsi);
 101           gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
 102         }
 103       for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
 104         {
 105           gimple *stmt = gsi_stmt (bsi);
 106           gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
 107         }
 108     }
 109 }
 110
 111
 112
 113 /*---------------------------------------------------------------------------
 114                               Debugging functions
 115 ---------------------------------------------------------------------------*/
 116
 117 /* Dump variable VAR and its may-aliases to FILE.  */
 118
 119 void
 120 dump_variable (FILE *file, tree var)
 121 {
 122   if (TREE_CODE (var) == SSA_NAME)
 123     {
 124       if (POINTER_TYPE_P (TREE_TYPE (var)))
 125         dump_points_to_info_for (file, var);
 126       var = SSA_NAME_VAR (var);
 127     }
 128
 129   if (var == NULL_TREE)
 130     {
 131       fprintf (file, "<nil>");
 132       return;
 133     }
 134
 135   print_generic_expr (file, var, dump_flags);
 136
 137   fprintf (file, ", UID D.%u", (unsigned) DECL_UID (var));
 138   if (DECL_PT_UID (var) != DECL_UID (var))
 139     fprintf (file, ", PT-UID D.%u", (unsigned) DECL_PT_UID (var));
 140
 141   fprintf (file, ", ");
 142   print_generic_expr (file, TREE_TYPE (var), dump_flags);
 143
 144   if (TREE_ADDRESSABLE (var))
 145     fprintf (file, ", is addressable");
 146
 147   if (is_global_var (var))
 148     fprintf (file, ", is global");
 149
 150   if (TREE_THIS_VOLATILE (var))
 151     fprintf (file, ", is volatile");
 152
 153   if (cfun && ssa_default_def (cfun, var))
 154     {
 155       fprintf (file, ", default def: ");
 156       print_generic_expr (file, ssa_default_def (cfun, var), dump_flags);
 157     }
 158
 159   if (DECL_INITIAL (var))
 160     {
 161       fprintf (file, ", initial: ");
 162       print_generic_expr (file, DECL_INITIAL (var), dump_flags);
 163     }
 164
 165   fprintf (file, "\n");
 166 }
 167
 168
 169 /* Dump variable VAR and its may-aliases to stderr.  */
 170
 171 DEBUG_FUNCTION void
 172 debug_variable (tree var)
 173 {
 174   dump_variable (stderr, var);
 175 }
 176
 177
 178 /* Dump various DFA statistics to FILE.  */
 179
 180 void
 181 dump_dfa_stats (FILE *file)
 182 {
 183   struct dfa_stats_d dfa_stats;
 184
 185   unsigned long size, total = 0;
 186   const char * const fmt_str   = "%-30s%-13s%12s\n";
 187   const char * const fmt_str_1 = "%-30s%13lu%11lu%c\n";
 188   const char * const fmt_str_3 = "%-43s%11lu%c\n";
 189   const char *funcname
 190     = lang_hooks.decl_printable_name (current_function_decl, 2);
 191
 192   collect_dfa_stats (&dfa_stats);
 193
 194   fprintf (file, "\nDFA Statistics for %s\n\n", funcname);
 195
 196   fprintf (file, "---------------------------------------------------------\n");
 197   fprintf (file, fmt_str, "", "  Number of  ", "Memory");
 198   fprintf (file, fmt_str, "", "  instances  ", "used ");
 199   fprintf (file, "---------------------------------------------------------\n");
 200
 201   size = dfa_stats.num_uses * sizeof (tree *);
 202   total += size;
 203   fprintf (file, fmt_str_1, "USE operands", dfa_stats.num_uses,
 204            SCALE (size), LABEL (size));
 205
 206   size = dfa_stats.num_defs * sizeof (tree *);
 207   total += size;
 208   fprintf (file, fmt_str_1, "DEF operands", dfa_stats.num_defs,
 209            SCALE (size), LABEL (size));
 210
 211   size = dfa_stats.num_vuses * sizeof (tree *);
 212   total += size;
 213   fprintf (file, fmt_str_1, "VUSE operands", dfa_stats.num_vuses,
 214            SCALE (size), LABEL (size));
 215
 216   size = dfa_stats.num_vdefs * sizeof (tree *);
 217   total += size;
 218   fprintf (file, fmt_str_1, "VDEF operands", dfa_stats.num_vdefs,
 219            SCALE (size), LABEL (size));
 220
 221   size = dfa_stats.num_phis * sizeof (struct gphi);
 222   total += size;
 223   fprintf (file, fmt_str_1, "PHI nodes", dfa_stats.num_phis,
 224            SCALE (size), LABEL (size));
 225
 226   size = dfa_stats.num_phi_args * sizeof (struct phi_arg_d);
 227   total += size;
 228   fprintf (file, fmt_str_1, "PHI arguments", dfa_stats.num_phi_args,
 229            SCALE (size), LABEL (size));
 230
 231   fprintf (file, "---------------------------------------------------------\n");
 232   fprintf (file, fmt_str_3, "Total memory used by DFA/SSA data", SCALE (total),
 233            LABEL (total));
 234   fprintf (file, "---------------------------------------------------------\n");
 235   fprintf (file, "\n");
 236
 237   if (dfa_stats.num_phis)
 238     fprintf (file, "Average number of arguments per PHI node: %.1f (max: %ld)\n",
 239              (float) dfa_stats.num_phi_args / (float) dfa_stats.num_phis,
 240              (long) dfa_stats.max_num_phi_args);
 241
 242   fprintf (file, "\n");
 243 }
 244
 245
 246 /* Dump DFA statistics on stderr.  */
 247
 248 DEBUG_FUNCTION void
 249 debug_dfa_stats (void)
 250 {
 251   dump_dfa_stats (stderr);
 252 }
 253
 254
 255 /* Collect DFA statistics and store them in the structure pointed to by
 256    DFA_STATS_P.  */
 257
 258 static void
 259 collect_dfa_stats (struct dfa_stats_d *dfa_stats_p ATTRIBUTE_UNUSED)
 260 {
 261   basic_block bb;
 262
 263   gcc_assert (dfa_stats_p);
 264
 265   memset ((void *)dfa_stats_p, 0, sizeof (struct dfa_stats_d));
 266
 267   /* Walk all the statements in the function counting references.  */
 268   FOR_EACH_BB_FN (bb, cfun)
 269     {
 270       for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si);
 271            gsi_next (&si))
 272         {
 273           gphi *phi = si.phi ();
 274           dfa_stats_p->num_phis++;
 275           dfa_stats_p->num_phi_args += gimple_phi_num_args (phi);
 276           if (gimple_phi_num_args (phi) > dfa_stats_p->max_num_phi_args)
 277             dfa_stats_p->max_num_phi_args = gimple_phi_num_args (phi);
 278         }
 279
 280       for (gimple_stmt_iterator si = gsi_start_bb (bb); !gsi_end_p (si);
 281            gsi_next (&si))
 282         {
 283           gimple *stmt = gsi_stmt (si);
 284           dfa_stats_p->num_defs += NUM_SSA_OPERANDS (stmt, SSA_OP_DEF);
 285           dfa_stats_p->num_uses += NUM_SSA_OPERANDS (stmt, SSA_OP_USE);
 286           dfa_stats_p->num_vdefs += gimple_vdef (stmt) ? 1 : 0;
 287           dfa_stats_p->num_vuses += gimple_vuse (stmt) ? 1 : 0;
 288         }
 289     }
 290 }
 291
 292
 293 /*---------------------------------------------------------------------------
 294                              Miscellaneous helpers
 295 ---------------------------------------------------------------------------*/
 296
 297 /* Lookup VAR UID in the default_defs hashtable and return the associated
 298    variable.  */
 299
 300 tree
 301 ssa_default_def (struct function *fn, tree var)
 302 {
 303   struct tree_decl_minimal ind;
 304   struct tree_ssa_name in;
 305   gcc_assert (VAR_P (var)
 306               || TREE_CODE (var) == PARM_DECL
 307               || TREE_CODE (var) == RESULT_DECL);
 308
 309   /* Always NULL_TREE for rtl function dumps.  */
 310   if (!fn->gimple_df)
 311     return NULL_TREE;
 312
 313   in.var = (tree)&ind;
 314   ind.uid = DECL_UID (var);
 315   return DEFAULT_DEFS (fn)->find_with_hash ((tree)&in, DECL_UID (var));
 316 }
 317
 318 /* Insert the pair VAR's UID, DEF into the default_defs hashtable
 319    of function FN.  */
 320
 321 void
 322 set_ssa_default_def (struct function *fn, tree var, tree def)
 323 {
 324   struct tree_decl_minimal ind;
 325   struct tree_ssa_name in;
 326
 327   gcc_assert (VAR_P (var)
 328               || TREE_CODE (var) == PARM_DECL
 329               || TREE_CODE (var) == RESULT_DECL);
 330   in.var = (tree)&ind;
 331   ind.uid = DECL_UID (var);
 332   if (!def)
 333     {
 334       tree *loc = DEFAULT_DEFS (fn)->find_slot_with_hash ((tree)&in,
 335                                                           DECL_UID (var),
 336                                                           NO_INSERT);
 337       if (loc)
 338         {
 339           SSA_NAME_IS_DEFAULT_DEF (*(tree *)loc) = false;
 340           DEFAULT_DEFS (fn)->clear_slot (loc);
 341         }
 342       return;
 343     }
 344   gcc_assert (TREE_CODE (def) == SSA_NAME && SSA_NAME_VAR (def) == var);
 345   tree *loc = DEFAULT_DEFS (fn)->find_slot_with_hash ((tree)&in,
 346                                                       DECL_UID (var), INSERT);
 347
 348   /* Default definition might be changed by tail call optimization.  */
 349   if (*loc)
 350     SSA_NAME_IS_DEFAULT_DEF (*loc) = false;
 351
 352    /* Mark DEF as the default definition for VAR.  */
 353   *loc = def;
 354   SSA_NAME_IS_DEFAULT_DEF (def) = true;
 355 }
 356
 357 /* Retrieve or create a default definition for VAR.  */
 358
 359 tree
 360 get_or_create_ssa_default_def (struct function *fn, tree var)
 361 {
 362   tree ddef = ssa_default_def (fn, var);
 363   if (ddef == NULL_TREE)
 364     {
 365       ddef = make_ssa_name_fn (fn, var, gimple_build_nop ());
 366       set_ssa_default_def (fn, var, ddef);
 367     }
 368   return ddef;
 369 }
 370
 371
 372 /* If EXP is a handled component reference for a structure, return the
 373    base variable.  The access range is delimited by bit positions *POFFSET and
 374    *POFFSET + *PMAX_SIZE.  The access size is *PSIZE bits.  If either
 375    *PSIZE or *PMAX_SIZE is -1, they could not be determined.  If *PSIZE
 376    and *PMAX_SIZE are equal, the access is non-variable.  If *PREVERSE is
 377    true, the storage order of the reference is reversed.  */
 378
 379 tree
 380 get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset,
 381                          HOST_WIDE_INT *psize,
 382                          HOST_WIDE_INT *pmax_size,
 383                          bool *preverse)
 384 {
 385   offset_int bitsize = -1;
 386   offset_int maxsize;
 387   tree size_tree = NULL_TREE;
 388   offset_int bit_offset = 0;
 389   bool seen_variable_array_ref = false;
 390
 391   /* First get the final access size and the storage order from just the
 392      outermost expression.  */
 393   if (TREE_CODE (exp) == COMPONENT_REF)
 394     size_tree = DECL_SIZE (TREE_OPERAND (exp, 1));
 395   else if (TREE_CODE (exp) == BIT_FIELD_REF)
 396     size_tree = TREE_OPERAND (exp, 1);
 397   else if (!VOID_TYPE_P (TREE_TYPE (exp)))
 398     {
 399       machine_mode mode = TYPE_MODE (TREE_TYPE (exp));
 400       if (mode == BLKmode)
 401         size_tree = TYPE_SIZE (TREE_TYPE (exp));
 402       else
 403         bitsize = int (GET_MODE_BITSIZE (mode));
 404     }
 405   if (size_tree != NULL_TREE
 406       && TREE_CODE (size_tree) == INTEGER_CST)
 407     bitsize = wi::to_offset (size_tree);
 408
 409   *preverse = reverse_storage_order_for_component_p (exp);
 410
 411   /* Initially, maxsize is the same as the accessed element size.
 412      In the following it will only grow (or become -1).  */
 413   maxsize = bitsize;
 414
 415   /* Compute cumulative bit-offset for nested component-refs and array-refs,
 416      and find the ultimate containing object.  */
 417   while (1)
 418     {
 419       switch (TREE_CODE (exp))
 420         {
 421         case BIT_FIELD_REF:
 422           bit_offset += wi::to_offset (TREE_OPERAND (exp, 2));
 423           break;
 424
 425         case COMPONENT_REF:
 426           {
 427             tree field = TREE_OPERAND (exp, 1);
 428             tree this_offset = component_ref_field_offset (exp);
 429
 430             if (this_offset && TREE_CODE (this_offset) == INTEGER_CST)
 431               {
 432                 offset_int woffset = (wi::to_offset (this_offset)
 433                                       << LOG2_BITS_PER_UNIT);
 434                 woffset += wi::to_offset (DECL_FIELD_BIT_OFFSET (field));
 435                 bit_offset += woffset;
 436
 437                 /* If we had seen a variable array ref already and we just
 438                    referenced the last field of a struct or a union member
 439                    then we have to adjust maxsize by the padding at the end
 440                    of our field.  */
 441                 if (seen_variable_array_ref && maxsize != -1)
 442                   {
 443                     tree stype = TREE_TYPE (TREE_OPERAND (exp, 0));
 444                     tree next = DECL_CHAIN (field);
 445                     while (next && TREE_CODE (next) != FIELD_DECL)
 446                       next = DECL_CHAIN (next);
 447                     if (!next
 448                         || TREE_CODE (stype) != RECORD_TYPE)
 449                       {
 450                         tree fsize = DECL_SIZE_UNIT (field);
 451                         tree ssize = TYPE_SIZE_UNIT (stype);
 452                         if (fsize == NULL
 453                             || TREE_CODE (fsize) != INTEGER_CST
 454                             || ssize == NULL
 455                             || TREE_CODE (ssize) != INTEGER_CST)
 456                           maxsize = -1;
 457                         else
 458                           {
 459                             offset_int tem = (wi::to_offset (ssize)
 460                                               - wi::to_offset (fsize));
 461                             tem <<= LOG2_BITS_PER_UNIT;
 462                             tem -= woffset;
 463                             maxsize += tem;
 464                           }
 465                       }
 466                   }
 467               }
 468             else
 469               {
 470                 tree csize = TYPE_SIZE (TREE_TYPE (TREE_OPERAND (exp, 0)));
 471                 /* We need to adjust maxsize to the whole structure bitsize.
 472                    But we can subtract any constant offset seen so far,
 473                    because that would get us out of the structure otherwise.  */
 474                 if (maxsize != -1
 475                     && csize
 476                     && TREE_CODE (csize) == INTEGER_CST)
 477                   maxsize = wi::to_offset (csize) - bit_offset;
 478                 else
 479                   maxsize = -1;
 480               }
 481           }
 482           break;
 483
 484         case ARRAY_REF:
 485         case ARRAY_RANGE_REF:
 486           {
 487             tree index = TREE_OPERAND (exp, 1);
 488             tree low_bound, unit_size;
 489
 490             /* If the resulting bit-offset is constant, track it.  */
 491             if (TREE_CODE (index) == INTEGER_CST
 492                 && (low_bound = array_ref_low_bound (exp),
 493                     TREE_CODE (low_bound) == INTEGER_CST)
 494                 && (unit_size = array_ref_element_size (exp),
 495                     TREE_CODE (unit_size) == INTEGER_CST))
 496               {
 497                 offset_int woffset
 498                   = wi::sext (wi::to_offset (index) - wi::to_offset (low_bound),
 499                               TYPE_PRECISION (TREE_TYPE (index)));
 500                 woffset *= wi::to_offset (unit_size);
 501                 woffset <<= LOG2_BITS_PER_UNIT;
 502                 bit_offset += woffset;
 503
 504                 /* An array ref with a constant index up in the structure
 505                    hierarchy will constrain the size of any variable array ref
 506                    lower in the access hierarchy.  */
 507                 seen_variable_array_ref = false;
 508               }
 509             else
 510               {
 511                 tree asize = TYPE_SIZE (TREE_TYPE (TREE_OPERAND (exp, 0)));
 512                 /* We need to adjust maxsize to the whole array bitsize.
 513                    But we can subtract any constant offset seen so far,
 514                    because that would get us outside of the array otherwise.  */
 515                 if (maxsize != -1
 516                     && asize
 517                     && TREE_CODE (asize) == INTEGER_CST)
 518                   maxsize = wi::to_offset (asize) - bit_offset;
 519                 else
 520                   maxsize = -1;
 521
 522                 /* Remember that we have seen an array ref with a variable
 523                    index.  */
 524                 seen_variable_array_ref = true;
 525               }
 526           }
 527           break;
 528
 529         case REALPART_EXPR:
 530           break;
 531
 532         case IMAGPART_EXPR:
 533           bit_offset += bitsize;
 534           break;
 535
 536         case VIEW_CONVERT_EXPR:
 537           break;
 538
 539         case TARGET_MEM_REF:
 540           /* Via the variable index or index2 we can reach the
 541              whole object.  Still hand back the decl here.  */
 542           if (TREE_CODE (TMR_BASE (exp)) == ADDR_EXPR
 543               && (TMR_INDEX (exp) || TMR_INDEX2 (exp)))
 544             {
 545               exp = TREE_OPERAND (TMR_BASE (exp), 0);
 546               bit_offset = 0;
 547               maxsize = -1;
 548               goto done;
 549             }
 550           /* Fallthru.  */
 551         case MEM_REF:
 552           /* We need to deal with variable arrays ending structures such as
 553              struct { int length; int a[1]; } x;           x.a[d]
 554              struct { struct { int a; int b; } a[1]; } x;  x.a[d].a
 555              struct { struct { int a[1]; } a[1]; } x;      x.a[0][d], x.a[d][0]
 556              struct { int len; union { int a[1]; struct X x; } u; } x; x.u.a[d]
 557              where we do not know maxsize for variable index accesses to
 558              the array.  The simplest way to conservatively deal with this
 559              is to punt in the case that offset + maxsize reaches the
 560              base type boundary.  This needs to include possible trailing
 561              padding that is there for alignment purposes.  */
 562           if (seen_variable_array_ref
 563               && maxsize != -1
 564               && (TYPE_SIZE (TREE_TYPE (exp)) == NULL_TREE
 565                   || TREE_CODE (TYPE_SIZE (TREE_TYPE (exp))) != INTEGER_CST
 566                   || (bit_offset + maxsize
 567                       == wi::to_offset (TYPE_SIZE (TREE_TYPE (exp))))))
 568             maxsize = -1;
 569
 570           /* Hand back the decl for MEM[&decl, off].  */
 571           if (TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR)
 572             {
 573               if (integer_zerop (TREE_OPERAND (exp, 1)))
 574                 exp = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
 575               else
 576                 {
 577                   offset_int off = mem_ref_offset (exp);
 578                   off <<= LOG2_BITS_PER_UNIT;
 579                   off += bit_offset;
 580                   if (wi::fits_shwi_p (off))
 581                     {
 582                       bit_offset = off;
 583                       exp = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
 584                     }
 585                 }
 586             }
 587           goto done;
 588
 589         default:
 590           goto done;
 591         }
 592
 593       exp = TREE_OPERAND (exp, 0);
 594     }
 595
 596  done:
 597   if (!wi::fits_shwi_p (bitsize) || wi::neg_p (bitsize))
 598     {
 599       *poffset = 0;
 600       *psize = -1;
 601       *pmax_size = -1;
 602
 603       return exp;
 604     }
 605
 606   *psize = bitsize.to_shwi ();
 607
 608   if (!wi::fits_shwi_p (bit_offset))
 609     {
 610       *poffset = 0;
 611       *pmax_size = -1;
 612
 613       return exp;
 614     }
 615
 616   /* In case of a decl or constant base object we can do better.  */
 617
 618   if (DECL_P (exp))
 619     {
 620       if (flag_unconstrained_commons && VAR_P (exp) && DECL_COMMON (exp))
 621         {
 622           tree sz_tree = TYPE_SIZE (TREE_TYPE (exp));
 623           /* If size is unknown, or we have read to the end, assume there
 624              may be more to the structure than we are told.  */
 625           if (TREE_CODE (TREE_TYPE (exp)) == ARRAY_TYPE
 626               || (seen_variable_array_ref
 627                   && (sz_tree == NULL_TREE
 628                       || TREE_CODE (sz_tree) != INTEGER_CST
 629                       || (bit_offset + maxsize == wi::to_offset (sz_tree)))))
 630             maxsize = -1;
 631         }
 632       /* If maxsize is unknown adjust it according to the size of the
 633          base decl.  */
 634       else if (maxsize == -1
 635           && DECL_SIZE (exp)
 636           && TREE_CODE (DECL_SIZE (exp)) == INTEGER_CST)
 637         maxsize = wi::to_offset (DECL_SIZE (exp)) - bit_offset;
 638     }
 639   else if (CONSTANT_CLASS_P (exp))
 640     {
 641       /* If maxsize is unknown adjust it according to the size of the
 642          base type constant.  */
 643       if (maxsize == -1
 644           && TYPE_SIZE (TREE_TYPE (exp))
 645           && TREE_CODE (TYPE_SIZE (TREE_TYPE (exp))) == INTEGER_CST)
 646         maxsize = (wi::to_offset (TYPE_SIZE (TREE_TYPE (exp)))
 647                    - bit_offset);
 648     }
 649
 650   /* ???  Due to negative offsets in ARRAY_REF we can end up with
 651      negative bit_offset here.  We might want to store a zero offset
 652      in this case.  */
 653   *poffset = bit_offset.to_shwi ();
 654   if (!wi::fits_shwi_p (maxsize) || wi::neg_p (maxsize))
 655     *pmax_size = -1;
 656   else
 657     {
 658       *pmax_size = maxsize.to_shwi ();
 659       if (*poffset > HOST_WIDE_INT_MAX - *pmax_size)
 660         *pmax_size = -1;
 661     }
 662
 663   /* Punt if *POFFSET + *PSIZE overflows in HOST_WIDE_INT, the callers don't
 664      check for such overflows individually and assume it works.  */
 665   if (*psize != -1 && *poffset > HOST_WIDE_INT_MAX - *psize)
 666     {
 667       *poffset = 0;
 668       *psize = -1;
 669       *pmax_size = -1;
 670
 671       return exp;
 672     }
 673
 674   return exp;
 675 }
 676
 677 /* Returns the base object and a constant BITS_PER_UNIT offset in *POFFSET that
 678    denotes the starting address of the memory access EXP.
 679    Returns NULL_TREE if the offset is not constant or any component
 680    is not BITS_PER_UNIT-aligned.
 681    VALUEIZE if non-NULL is used to valueize SSA names.  It should return
 682    its argument or a constant if the argument is known to be constant.  */
 683
 684 tree
 685 get_addr_base_and_unit_offset_1 (tree exp, HOST_WIDE_INT *poffset,
 686                                  tree (*valueize) (tree))
 687 {
 688   HOST_WIDE_INT byte_offset = 0;
 689
 690   /* Compute cumulative byte-offset for nested component-refs and array-refs,
 691      and find the ultimate containing object.  */
 692   while (1)
 693     {
 694       switch (TREE_CODE (exp))
 695         {
 696         case BIT_FIELD_REF:
 697           {
 698             HOST_WIDE_INT this_off = TREE_INT_CST_LOW (TREE_OPERAND (exp, 2));
 699             if (this_off % BITS_PER_UNIT)
 700               return NULL_TREE;
 701             byte_offset += this_off / BITS_PER_UNIT;
 702           }
 703           break;
 704
 705         case COMPONENT_REF:
 706           {
 707             tree field = TREE_OPERAND (exp, 1);
 708             tree this_offset = component_ref_field_offset (exp);
 709             HOST_WIDE_INT hthis_offset;
 710
 711             if (!this_offset
 712                 || TREE_CODE (this_offset) != INTEGER_CST
 713                 || (TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field))
 714                     % BITS_PER_UNIT))
 715               return NULL_TREE;
 716
 717             hthis_offset = TREE_INT_CST_LOW (this_offset);
 718             hthis_offset += (TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field))
 719                              / BITS_PER_UNIT);
 720             byte_offset += hthis_offset;
 721           }
 722           break;
 723
 724         case ARRAY_REF:
 725         case ARRAY_RANGE_REF:
 726           {
 727             tree index = TREE_OPERAND (exp, 1);
 728             tree low_bound, unit_size;
 729
 730             if (valueize
 731                 && TREE_CODE (index) == SSA_NAME)
 732               index = (*valueize) (index);
 733
 734             /* If the resulting bit-offset is constant, track it.  */
 735             if (TREE_CODE (index) == INTEGER_CST
 736                 && (low_bound = array_ref_low_bound (exp),
 737                     TREE_CODE (low_bound) == INTEGER_CST)
 738                 && (unit_size = array_ref_element_size (exp),
 739                     TREE_CODE (unit_size) == INTEGER_CST))
 740               {
 741                 offset_int woffset
 742                   = wi::sext (wi::to_offset (index) - wi::to_offset (low_bound),
 743                               TYPE_PRECISION (TREE_TYPE (index)));
 744                 woffset *= wi::to_offset (unit_size);
 745                 byte_offset += woffset.to_shwi ();
 746               }
 747             else
 748               return NULL_TREE;
 749           }
 750           break;
 751
 752         case REALPART_EXPR:
 753           break;
 754
 755         case IMAGPART_EXPR:
 756           byte_offset += TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (exp)));
 757           break;
 758
 759         case VIEW_CONVERT_EXPR:
 760           break;
 761
 762         case MEM_REF:
 763           {
 764             tree base = TREE_OPERAND (exp, 0);
 765             if (valueize
 766                 && TREE_CODE (base) == SSA_NAME)
 767               base = (*valueize) (base);
 768
 769             /* Hand back the decl for MEM[&decl, off].  */
 770             if (TREE_CODE (base) == ADDR_EXPR)
 771               {
 772                 if (!integer_zerop (TREE_OPERAND (exp, 1)))
 773                   {
 774                     offset_int off = mem_ref_offset (exp);
 775                     byte_offset += off.to_short_addr ();
 776                   }
 777                 exp = TREE_OPERAND (base, 0);
 778               }
 779             goto done;
 780           }
 781
 782         case TARGET_MEM_REF:
 783           {
 784             tree base = TREE_OPERAND (exp, 0);
 785             if (valueize
 786                 && TREE_CODE (base) == SSA_NAME)
 787               base = (*valueize) (base);
 788
 789             /* Hand back the decl for MEM[&decl, off].  */
 790             if (TREE_CODE (base) == ADDR_EXPR)
 791               {
 792                 if (TMR_INDEX (exp) || TMR_INDEX2 (exp))
 793                   return NULL_TREE;
 794                 if (!integer_zerop (TMR_OFFSET (exp)))
 795                   {
 796                     offset_int off = mem_ref_offset (exp);
 797                     byte_offset += off.to_short_addr ();
 798                   }
 799                 exp = TREE_OPERAND (base, 0);
 800               }
 801             goto done;
 802           }
 803
 804         default:
 805           goto done;
 806         }
 807
 808       exp = TREE_OPERAND (exp, 0);
 809     }
 810 done:
 811
 812   *poffset = byte_offset;
 813   return exp;
 814 }
 815
 816 /* Returns the base object and a constant BITS_PER_UNIT offset in *POFFSET that
 817    denotes the starting address of the memory access EXP.
 818    Returns NULL_TREE if the offset is not constant or any component
 819    is not BITS_PER_UNIT-aligned.  */
 820
 821 tree
 822 get_addr_base_and_unit_offset (tree exp, HOST_WIDE_INT *poffset)
 823 {
 824   return get_addr_base_and_unit_offset_1 (exp, poffset, NULL);
 825 }
 826
 827 /* Returns true if STMT references an SSA_NAME that has
 828    SSA_NAME_OCCURS_IN_ABNORMAL_PHI set, otherwise false.  */
 829
 830 bool
 831 stmt_references_abnormal_ssa_name (gimple *stmt)
 832 {
 833   ssa_op_iter oi;
 834   use_operand_p use_p;
 835
 836   FOR_EACH_SSA_USE_OPERAND (use_p, stmt, oi, SSA_OP_USE)
 837     {
 838       if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (use_p)))
 839         return true;
 840     }
 841
 842   return false;
 843 }
 844
 845 /* If STMT takes any abnormal PHI values as input, replace them with
 846    local copies.  */
 847
 848 void
 849 replace_abnormal_ssa_names (gimple *stmt)
 850 {
 851   ssa_op_iter oi;
 852   use_operand_p use_p;
 853
 854   FOR_EACH_SSA_USE_OPERAND (use_p, stmt, oi, SSA_OP_USE)
 855     {
 856       tree op = USE_FROM_PTR (use_p);
 857       if (TREE_CODE (op) == SSA_NAME && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
 858         {
 859           gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
 860           tree new_name = make_ssa_name (TREE_TYPE (op));
 861           gassign *assign = gimple_build_assign (new_name, op);
 862           gsi_insert_before (&gsi, assign, GSI_SAME_STMT);
 863           SET_USE (use_p, new_name);
 864         }
 865     }
 866 }
 867
 868 /* Pair of tree and a sorting index, for dump_enumerated_decls.  */
 869 struct GTY(()) numbered_tree
 870 {
 871   tree t;
 872   int num;
 873 };
 874
 875
 876 /* Compare two declarations references by their DECL_UID / sequence number.
 877    Called via qsort.  */
 878
 879 static int
 880 compare_decls_by_uid (const void *pa, const void *pb)
 881 {
 882   const numbered_tree *nt_a = ((const numbered_tree *)pa);
 883   const numbered_tree *nt_b = ((const numbered_tree *)pb);
 884
 885   if (DECL_UID (nt_a->t) != DECL_UID (nt_b->t))
 886     return  DECL_UID (nt_a->t) - DECL_UID (nt_b->t);
 887   return nt_a->num - nt_b->num;
 888 }
 889
 890 /* Called via walk_gimple_stmt / walk_gimple_op by dump_enumerated_decls.  */
 891 static tree
 892 dump_enumerated_decls_push (tree *tp, int *walk_subtrees, void *data)
 893 {
 894   struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
 895   vec<numbered_tree> *list = (vec<numbered_tree> *) wi->info;
 896   numbered_tree nt;
 897
 898   if (!DECL_P (*tp))
 899     return NULL_TREE;
 900   nt.t = *tp;
 901   nt.num = list->length ();
 902   list->safe_push (nt);
 903   *walk_subtrees = 0;
 904   return NULL_TREE;
 905 }
 906
 907 /* Find all the declarations used by the current function, sort them by uid,
 908    and emit the sorted list.  Each declaration is tagged with a sequence
 909    number indicating when it was found during statement / tree walking,
 910    so that TDF_NOUID comparisons of anonymous declarations are still
 911    meaningful.  Where a declaration was encountered more than once, we
 912    emit only the sequence number of the first encounter.
 913    FILE is the dump file where to output the list and FLAGS is as in
 914    print_generic_expr.  */
 915 void
 916 dump_enumerated_decls (FILE *file, dump_flags_t flags)
 917 {
 918   basic_block bb;
 919   struct walk_stmt_info wi;
 920   auto_vec<numbered_tree, 40> decl_list;
 921
 922   memset (&wi, '\0', sizeof (wi));
 923   wi.info = (void *) &decl_list;
 924   FOR_EACH_BB_FN (bb, cfun)
 925     {
 926       gimple_stmt_iterator gsi;
 927
 928       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 929         if (!is_gimple_debug (gsi_stmt (gsi)))
 930           walk_gimple_stmt (&gsi, NULL, dump_enumerated_decls_push, &wi);
 931     }
 932   decl_list.qsort (compare_decls_by_uid);
 933   if (decl_list.length ())
 934     {
 935       unsigned ix;
 936       numbered_tree *ntp;
 937       tree last = NULL_TREE;
 938
 939       fprintf (file, "Declarations used by %s, sorted by DECL_UID:\n",
 940                current_function_name ());
 941       FOR_EACH_VEC_ELT (decl_list, ix, ntp)
 942         {
 943           if (ntp->t == last)
 944             continue;
 945           fprintf (file, "%d: ", ntp->num);
 946           print_generic_decl (file, ntp->t, flags);
 947           fprintf (file, "\n");
 948           last = ntp->t;
 949         }
 950     }
 951 }