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     *pmax_size = maxsize.to_shwi ();
 658
 659   return exp;
 660 }
 661
 662 /* Returns the base object and a constant BITS_PER_UNIT offset in *POFFSET that
 663    denotes the starting address of the memory access EXP.
 664    Returns NULL_TREE if the offset is not constant or any component
 665    is not BITS_PER_UNIT-aligned.
 666    VALUEIZE if non-NULL is used to valueize SSA names.  It should return
 667    its argument or a constant if the argument is known to be constant.  */
 668
 669 tree
 670 get_addr_base_and_unit_offset_1 (tree exp, HOST_WIDE_INT *poffset,
 671                                  tree (*valueize) (tree))
 672 {
 673   HOST_WIDE_INT byte_offset = 0;
 674
 675   /* Compute cumulative byte-offset for nested component-refs and array-refs,
 676      and find the ultimate containing object.  */
 677   while (1)
 678     {
 679       switch (TREE_CODE (exp))
 680         {
 681         case BIT_FIELD_REF:
 682           {
 683             HOST_WIDE_INT this_off = TREE_INT_CST_LOW (TREE_OPERAND (exp, 2));
 684             if (this_off % BITS_PER_UNIT)
 685               return NULL_TREE;
 686             byte_offset += this_off / BITS_PER_UNIT;
 687           }
 688           break;
 689
 690         case COMPONENT_REF:
 691           {
 692             tree field = TREE_OPERAND (exp, 1);
 693             tree this_offset = component_ref_field_offset (exp);
 694             HOST_WIDE_INT hthis_offset;
 695
 696             if (!this_offset
 697                 || TREE_CODE (this_offset) != INTEGER_CST
 698                 || (TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field))
 699                     % BITS_PER_UNIT))
 700               return NULL_TREE;
 701
 702             hthis_offset = TREE_INT_CST_LOW (this_offset);
 703             hthis_offset += (TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field))
 704                              / BITS_PER_UNIT);
 705             byte_offset += hthis_offset;
 706           }
 707           break;
 708
 709         case ARRAY_REF:
 710         case ARRAY_RANGE_REF:
 711           {
 712             tree index = TREE_OPERAND (exp, 1);
 713             tree low_bound, unit_size;
 714
 715             if (valueize
 716                 && TREE_CODE (index) == SSA_NAME)
 717               index = (*valueize) (index);
 718
 719             /* If the resulting bit-offset is constant, track it.  */
 720             if (TREE_CODE (index) == INTEGER_CST
 721                 && (low_bound = array_ref_low_bound (exp),
 722                     TREE_CODE (low_bound) == INTEGER_CST)
 723                 && (unit_size = array_ref_element_size (exp),
 724                     TREE_CODE (unit_size) == INTEGER_CST))
 725               {
 726                 offset_int woffset
 727                   = wi::sext (wi::to_offset (index) - wi::to_offset (low_bound),
 728                               TYPE_PRECISION (TREE_TYPE (index)));
 729                 woffset *= wi::to_offset (unit_size);
 730                 byte_offset += woffset.to_shwi ();
 731               }
 732             else
 733               return NULL_TREE;
 734           }
 735           break;
 736
 737         case REALPART_EXPR:
 738           break;
 739
 740         case IMAGPART_EXPR:
 741           byte_offset += TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (exp)));
 742           break;
 743
 744         case VIEW_CONVERT_EXPR:
 745           break;
 746
 747         case MEM_REF:
 748           {
 749             tree base = TREE_OPERAND (exp, 0);
 750             if (valueize
 751                 && TREE_CODE (base) == SSA_NAME)
 752               base = (*valueize) (base);
 753
 754             /* Hand back the decl for MEM[&decl, off].  */
 755             if (TREE_CODE (base) == ADDR_EXPR)
 756               {
 757                 if (!integer_zerop (TREE_OPERAND (exp, 1)))
 758                   {
 759                     offset_int off = mem_ref_offset (exp);
 760                     byte_offset += off.to_short_addr ();
 761                   }
 762                 exp = TREE_OPERAND (base, 0);
 763               }
 764             goto done;
 765           }
 766
 767         case TARGET_MEM_REF:
 768           {
 769             tree base = TREE_OPERAND (exp, 0);
 770             if (valueize
 771                 && TREE_CODE (base) == SSA_NAME)
 772               base = (*valueize) (base);
 773
 774             /* Hand back the decl for MEM[&decl, off].  */
 775             if (TREE_CODE (base) == ADDR_EXPR)
 776               {
 777                 if (TMR_INDEX (exp) || TMR_INDEX2 (exp))
 778                   return NULL_TREE;
 779                 if (!integer_zerop (TMR_OFFSET (exp)))
 780                   {
 781                     offset_int off = mem_ref_offset (exp);
 782                     byte_offset += off.to_short_addr ();
 783                   }
 784                 exp = TREE_OPERAND (base, 0);
 785               }
 786             goto done;
 787           }
 788
 789         default:
 790           goto done;
 791         }
 792
 793       exp = TREE_OPERAND (exp, 0);
 794     }
 795 done:
 796
 797   *poffset = byte_offset;
 798   return exp;
 799 }
 800
 801 /* Returns the base object and a constant BITS_PER_UNIT offset in *POFFSET that
 802    denotes the starting address of the memory access EXP.
 803    Returns NULL_TREE if the offset is not constant or any component
 804    is not BITS_PER_UNIT-aligned.  */
 805
 806 tree
 807 get_addr_base_and_unit_offset (tree exp, HOST_WIDE_INT *poffset)
 808 {
 809   return get_addr_base_and_unit_offset_1 (exp, poffset, NULL);
 810 }
 811
 812 /* Returns true if STMT references an SSA_NAME that has
 813    SSA_NAME_OCCURS_IN_ABNORMAL_PHI set, otherwise false.  */
 814
 815 bool
 816 stmt_references_abnormal_ssa_name (gimple *stmt)
 817 {
 818   ssa_op_iter oi;
 819   use_operand_p use_p;
 820
 821   FOR_EACH_SSA_USE_OPERAND (use_p, stmt, oi, SSA_OP_USE)
 822     {
 823       if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (use_p)))
 824         return true;
 825     }
 826
 827   return false;
 828 }
 829
 830 /* If STMT takes any abnormal PHI values as input, replace them with
 831    local copies.  */
 832
 833 void
 834 replace_abnormal_ssa_names (gimple *stmt)
 835 {
 836   ssa_op_iter oi;
 837   use_operand_p use_p;
 838
 839   FOR_EACH_SSA_USE_OPERAND (use_p, stmt, oi, SSA_OP_USE)
 840     {
 841       tree op = USE_FROM_PTR (use_p);
 842       if (TREE_CODE (op) == SSA_NAME && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
 843         {
 844           gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
 845           tree new_name = make_ssa_name (TREE_TYPE (op));
 846           gassign *assign = gimple_build_assign (new_name, op);
 847           gsi_insert_before (&gsi, assign, GSI_SAME_STMT);
 848           SET_USE (use_p, new_name);
 849         }
 850     }
 851 }
 852
 853 /* Pair of tree and a sorting index, for dump_enumerated_decls.  */
 854 struct GTY(()) numbered_tree
 855 {
 856   tree t;
 857   int num;
 858 };
 859
 860
 861 /* Compare two declarations references by their DECL_UID / sequence number.
 862    Called via qsort.  */
 863
 864 static int
 865 compare_decls_by_uid (const void *pa, const void *pb)
 866 {
 867   const numbered_tree *nt_a = ((const numbered_tree *)pa);
 868   const numbered_tree *nt_b = ((const numbered_tree *)pb);
 869
 870   if (DECL_UID (nt_a->t) != DECL_UID (nt_b->t))
 871     return  DECL_UID (nt_a->t) - DECL_UID (nt_b->t);
 872   return nt_a->num - nt_b->num;
 873 }
 874
 875 /* Called via walk_gimple_stmt / walk_gimple_op by dump_enumerated_decls.  */
 876 static tree
 877 dump_enumerated_decls_push (tree *tp, int *walk_subtrees, void *data)
 878 {
 879   struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
 880   vec<numbered_tree> *list = (vec<numbered_tree> *) wi->info;
 881   numbered_tree nt;
 882
 883   if (!DECL_P (*tp))
 884     return NULL_TREE;
 885   nt.t = *tp;
 886   nt.num = list->length ();
 887   list->safe_push (nt);
 888   *walk_subtrees = 0;
 889   return NULL_TREE;
 890 }
 891
 892 /* Find all the declarations used by the current function, sort them by uid,
 893    and emit the sorted list.  Each declaration is tagged with a sequence
 894    number indicating when it was found during statement / tree walking,
 895    so that TDF_NOUID comparisons of anonymous declarations are still
 896    meaningful.  Where a declaration was encountered more than once, we
 897    emit only the sequence number of the first encounter.
 898    FILE is the dump file where to output the list and FLAGS is as in
 899    print_generic_expr.  */
 900 void
 901 dump_enumerated_decls (FILE *file, dump_flags_t flags)
 902 {
 903   basic_block bb;
 904   struct walk_stmt_info wi;
 905   auto_vec<numbered_tree, 40> decl_list;
 906
 907   memset (&wi, '\0', sizeof (wi));
 908   wi.info = (void *) &decl_list;
 909   FOR_EACH_BB_FN (bb, cfun)
 910     {
 911       gimple_stmt_iterator gsi;
 912
 913       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 914         if (!is_gimple_debug (gsi_stmt (gsi)))
 915           walk_gimple_stmt (&gsi, NULL, dump_enumerated_decls_push, &wi);
 916     }
 917   decl_list.qsort (compare_decls_by_uid);
 918   if (decl_list.length ())
 919     {
 920       unsigned ix;
 921       numbered_tree *ntp;
 922       tree last = NULL_TREE;
 923
 924       fprintf (file, "Declarations used by %s, sorted by DECL_UID:\n",
 925                current_function_name ());
 926       FOR_EACH_VEC_ELT (decl_list, ix, ntp)
 927         {
 928           if (ntp->t == last)
 929             continue;
 930           fprintf (file, "%d: ", ntp->num);
 931           print_generic_decl (file, ntp->t, flags);
 932           fprintf (file, "\n");
 933           last = ntp->t;
 934         }
 935     }
 936 }