gcc/tree-object-size.c

   1 /* __builtin_object_size (ptr, object_size_type) computation
   2    Copyright (C) 2004-2014 Free Software Foundation, Inc.
   3    Contributed by Jakub Jelinek <jakub@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 "tm.h"
  25 #include "tree.h"
  26 #include "tree-object-size.h"
  27 #include "diagnostic-core.h"
  28 #include "gimple-pretty-print.h"
  29 #include "bitmap.h"
  30 #include "basic-block.h"
  31 #include "tree-ssa-alias.h"
  32 #include "internal-fn.h"
  33 #include "gimple-fold.h"
  34 #include "gimple-expr.h"
  35 #include "is-a.h"
  36 #include "gimple.h"
  37 #include "gimple-iterator.h"
  38 #include "gimple-ssa.h"
  39 #include "stringpool.h"
  40 #include "tree-ssanames.h"
  41 #include "tree-pass.h"
  42 #include "tree-ssa-propagate.h"
  43 #include "tree-phinodes.h"
  44 #include "ssa-iterators.h"
  45 #include "builtins.h"
  46
  47 struct object_size_info
  48 {
  49   int object_size_type;
  50   bitmap visited, reexamine;
  51   int pass;
  52   bool changed;
  53   unsigned int *depths;
  54   unsigned int *stack, *tos;
  55 };
  56
  57 static const unsigned HOST_WIDE_INT unknown[4] = { -1, -1, 0, 0 };
  58
  59 static tree compute_object_offset (const_tree, const_tree);
  60 static unsigned HOST_WIDE_INT addr_object_size (struct object_size_info *,
  61                                                 const_tree, int);
  62 static unsigned HOST_WIDE_INT alloc_object_size (const_gimple, int);
  63 static tree pass_through_call (const_gimple);
  64 static void collect_object_sizes_for (struct object_size_info *, tree);
  65 static void expr_object_size (struct object_size_info *, tree, tree);
  66 static bool merge_object_sizes (struct object_size_info *, tree, tree,
  67                                 unsigned HOST_WIDE_INT);
  68 static bool plus_stmt_object_size (struct object_size_info *, tree, gimple);
  69 static bool cond_expr_object_size (struct object_size_info *, tree, gimple);
  70 static void init_offset_limit (void);
  71 static void check_for_plus_in_loops (struct object_size_info *, tree);
  72 static void check_for_plus_in_loops_1 (struct object_size_info *, tree,
  73                                        unsigned int);
  74
  75 /* object_sizes[0] is upper bound for number of bytes till the end of
  76    the object.
  77    object_sizes[1] is upper bound for number of bytes till the end of
  78    the subobject (innermost array or field with address taken).
  79    object_sizes[2] is lower bound for number of bytes till the end of
  80    the object and object_sizes[3] lower bound for subobject.  */
  81 static vec<unsigned HOST_WIDE_INT> object_sizes[4];
  82
  83 /* Bitmaps what object sizes have been computed already.  */
  84 static bitmap computed[4];
  85
  86 /* Maximum value of offset we consider to be addition.  */
  87 static unsigned HOST_WIDE_INT offset_limit;
  88
  89
  90 /* Initialize OFFSET_LIMIT variable.  */
  91 static void
  92 init_offset_limit (void)
  93 {
  94   if (tree_fits_uhwi_p (TYPE_MAX_VALUE (sizetype)))
  95     offset_limit = tree_to_uhwi (TYPE_MAX_VALUE (sizetype));
  96   else
  97     offset_limit = -1;
  98   offset_limit /= 2;
  99 }
 100
 101
 102 /* Compute offset of EXPR within VAR.  Return error_mark_node
 103    if unknown.  */
 104
 105 static tree
 106 compute_object_offset (const_tree expr, const_tree var)
 107 {
 108   enum tree_code code = PLUS_EXPR;
 109   tree base, off, t;
 110
 111   if (expr == var)
 112     return size_zero_node;
 113
 114   switch (TREE_CODE (expr))
 115     {
 116     case COMPONENT_REF:
 117       base = compute_object_offset (TREE_OPERAND (expr, 0), var);
 118       if (base == error_mark_node)
 119         return base;
 120
 121       t = TREE_OPERAND (expr, 1);
 122       off = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (t),
 123                         size_int (tree_to_uhwi (DECL_FIELD_BIT_OFFSET (t))
 124                                   / BITS_PER_UNIT));
 125       break;
 126
 127     case REALPART_EXPR:
 128     CASE_CONVERT:
 129     case VIEW_CONVERT_EXPR:
 130     case NON_LVALUE_EXPR:
 131       return compute_object_offset (TREE_OPERAND (expr, 0), var);
 132
 133     case IMAGPART_EXPR:
 134       base = compute_object_offset (TREE_OPERAND (expr, 0), var);
 135       if (base == error_mark_node)
 136         return base;
 137
 138       off = TYPE_SIZE_UNIT (TREE_TYPE (expr));
 139       break;
 140
 141     case ARRAY_REF:
 142       base = compute_object_offset (TREE_OPERAND (expr, 0), var);
 143       if (base == error_mark_node)
 144         return base;
 145
 146       t = TREE_OPERAND (expr, 1);
 147       if (TREE_CODE (t) == INTEGER_CST && tree_int_cst_sgn (t) < 0)
 148         {
 149           code = MINUS_EXPR;
 150           t = fold_build1 (NEGATE_EXPR, TREE_TYPE (t), t);
 151         }
 152       t = fold_convert (sizetype, t);
 153       off = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (TREE_TYPE (expr)), t);
 154       break;
 155
 156     case MEM_REF:
 157       gcc_assert (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR);
 158       return wide_int_to_tree (sizetype, mem_ref_offset (expr));
 159
 160     default:
 161       return error_mark_node;
 162     }
 163
 164   return size_binop (code, base, off);
 165 }
 166
 167
 168 /* Compute __builtin_object_size for PTR, which is a ADDR_EXPR.
 169    OBJECT_SIZE_TYPE is the second argument from __builtin_object_size.
 170    If unknown, return unknown[object_size_type].  */
 171
 172 static unsigned HOST_WIDE_INT
 173 addr_object_size (struct object_size_info *osi, const_tree ptr,
 174                   int object_size_type)
 175 {
 176   tree pt_var, pt_var_size = NULL_TREE, var_size, bytes;
 177
 178   gcc_assert (TREE_CODE (ptr) == ADDR_EXPR);
 179
 180   pt_var = TREE_OPERAND (ptr, 0);
 181   while (handled_component_p (pt_var))
 182     pt_var = TREE_OPERAND (pt_var, 0);
 183
 184   if (pt_var
 185       && TREE_CODE (pt_var) == MEM_REF)
 186     {
 187       unsigned HOST_WIDE_INT sz;
 188
 189       if (!osi || (object_size_type & 1) != 0
 190           || TREE_CODE (TREE_OPERAND (pt_var, 0)) != SSA_NAME)
 191         {
 192           sz = compute_builtin_object_size (TREE_OPERAND (pt_var, 0),
 193                                             object_size_type & ~1);
 194         }
 195       else
 196         {
 197           tree var = TREE_OPERAND (pt_var, 0);
 198           if (osi->pass == 0)
 199             collect_object_sizes_for (osi, var);
 200           if (bitmap_bit_p (computed[object_size_type],
 201                             SSA_NAME_VERSION (var)))
 202             sz = object_sizes[object_size_type][SSA_NAME_VERSION (var)];
 203           else
 204             sz = unknown[object_size_type];
 205         }
 206       if (sz != unknown[object_size_type])
 207         {
 208           offset_int dsz = wi::sub (sz, mem_ref_offset (pt_var));
 209           if (wi::neg_p (dsz))
 210             sz = 0;
 211           else if (wi::fits_uhwi_p (dsz))
 212             sz = dsz.to_uhwi ();
 213           else
 214             sz = unknown[object_size_type];
 215         }
 216
 217       if (sz != unknown[object_size_type] && sz < offset_limit)
 218         pt_var_size = size_int (sz);
 219     }
 220   else if (pt_var
 221            && DECL_P (pt_var)
 222            && tree_fits_uhwi_p (DECL_SIZE_UNIT (pt_var))
 223            && tree_to_uhwi (DECL_SIZE_UNIT (pt_var)) < offset_limit)
 224     pt_var_size = DECL_SIZE_UNIT (pt_var);
 225   else if (pt_var
 226            && TREE_CODE (pt_var) == STRING_CST
 227            && TYPE_SIZE_UNIT (TREE_TYPE (pt_var))
 228            && tree_fits_uhwi_p (TYPE_SIZE_UNIT (TREE_TYPE (pt_var)))
 229            && tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (pt_var)))
 230               < offset_limit)
 231     pt_var_size = TYPE_SIZE_UNIT (TREE_TYPE (pt_var));
 232   else
 233     return unknown[object_size_type];
 234
 235   if (pt_var != TREE_OPERAND (ptr, 0))
 236     {
 237       tree var;
 238
 239       if (object_size_type & 1)
 240         {
 241           var = TREE_OPERAND (ptr, 0);
 242
 243           while (var != pt_var
 244                  && TREE_CODE (var) != BIT_FIELD_REF
 245                  && TREE_CODE (var) != COMPONENT_REF
 246                  && TREE_CODE (var) != ARRAY_REF
 247                  && TREE_CODE (var) != ARRAY_RANGE_REF
 248                  && TREE_CODE (var) != REALPART_EXPR
 249                  && TREE_CODE (var) != IMAGPART_EXPR)
 250             var = TREE_OPERAND (var, 0);
 251           if (var != pt_var && TREE_CODE (var) == ARRAY_REF)
 252             var = TREE_OPERAND (var, 0);
 253           if (! TYPE_SIZE_UNIT (TREE_TYPE (var))
 254               || ! tree_fits_uhwi_p (TYPE_SIZE_UNIT (TREE_TYPE (var)))
 255               || (pt_var_size
 256                   && tree_int_cst_lt (pt_var_size,
 257                                       TYPE_SIZE_UNIT (TREE_TYPE (var)))))
 258             var = pt_var;
 259           else if (var != pt_var && TREE_CODE (pt_var) == MEM_REF)
 260             {
 261               tree v = var;
 262               /* For &X->fld, compute object size only if fld isn't the last
 263                  field, as struct { int i; char c[1]; } is often used instead
 264                  of flexible array member.  */
 265               while (v && v != pt_var)
 266                 switch (TREE_CODE (v))
 267                   {
 268                   case ARRAY_REF:
 269                     if (TYPE_SIZE_UNIT (TREE_TYPE (TREE_OPERAND (v, 0)))
 270                         && TREE_CODE (TREE_OPERAND (v, 1)) == INTEGER_CST)
 271                       {
 272                         tree domain
 273                           = TYPE_DOMAIN (TREE_TYPE (TREE_OPERAND (v, 0)));
 274                         if (domain
 275                             && TYPE_MAX_VALUE (domain)
 276                             && TREE_CODE (TYPE_MAX_VALUE (domain))
 277                                == INTEGER_CST
 278                             && tree_int_cst_lt (TREE_OPERAND (v, 1),
 279                                                 TYPE_MAX_VALUE (domain)))
 280                           {
 281                             v = NULL_TREE;
 282                             break;
 283                           }
 284                       }
 285                     v = TREE_OPERAND (v, 0);
 286                     break;
 287                   case REALPART_EXPR:
 288                   case IMAGPART_EXPR:
 289                     v = NULL_TREE;
 290                     break;
 291                   case COMPONENT_REF:
 292                     if (TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE)
 293                       {
 294                         v = NULL_TREE;
 295                         break;
 296                       }
 297                     while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
 298                       if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
 299                           != UNION_TYPE
 300                           && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
 301                           != QUAL_UNION_TYPE)
 302                         break;
 303                       else
 304                         v = TREE_OPERAND (v, 0);
 305                     if (TREE_CODE (v) == COMPONENT_REF
 306                         && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
 307                            == RECORD_TYPE)
 308                       {
 309                         tree fld_chain = DECL_CHAIN (TREE_OPERAND (v, 1));
 310                         for (; fld_chain; fld_chain = DECL_CHAIN (fld_chain))
 311                           if (TREE_CODE (fld_chain) == FIELD_DECL)
 312                             break;
 313
 314                         if (fld_chain)
 315                           {
 316                             v = NULL_TREE;
 317                             break;
 318                           }
 319                         v = TREE_OPERAND (v, 0);
 320                       }
 321                     while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
 322                       if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
 323                           != UNION_TYPE
 324                           && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
 325                           != QUAL_UNION_TYPE)
 326                         break;
 327                       else
 328                         v = TREE_OPERAND (v, 0);
 329                     if (v != pt_var)
 330                       v = NULL_TREE;
 331                     else
 332                       v = pt_var;
 333                     break;
 334                   default:
 335                     v = pt_var;
 336                     break;
 337                   }
 338               if (v == pt_var)
 339                 var = pt_var;
 340             }
 341         }
 342       else
 343         var = pt_var;
 344
 345       if (var != pt_var)
 346         var_size = TYPE_SIZE_UNIT (TREE_TYPE (var));
 347       else if (!pt_var_size)
 348         return unknown[object_size_type];
 349       else
 350         var_size = pt_var_size;
 351       bytes = compute_object_offset (TREE_OPERAND (ptr, 0), var);
 352       if (bytes != error_mark_node)
 353         {
 354           if (TREE_CODE (bytes) == INTEGER_CST
 355               && tree_int_cst_lt (var_size, bytes))
 356             bytes = size_zero_node;
 357           else
 358             bytes = size_binop (MINUS_EXPR, var_size, bytes);
 359         }
 360       if (var != pt_var
 361           && pt_var_size
 362           && TREE_CODE (pt_var) == MEM_REF
 363           && bytes != error_mark_node)
 364         {
 365           tree bytes2 = compute_object_offset (TREE_OPERAND (ptr, 0), pt_var);
 366           if (bytes2 != error_mark_node)
 367             {
 368               if (TREE_CODE (bytes2) == INTEGER_CST
 369                   && tree_int_cst_lt (pt_var_size, bytes2))
 370                 bytes2 = size_zero_node;
 371               else
 372                 bytes2 = size_binop (MINUS_EXPR, pt_var_size, bytes2);
 373               bytes = size_binop (MIN_EXPR, bytes, bytes2);
 374             }
 375         }
 376     }
 377   else if (!pt_var_size)
 378     return unknown[object_size_type];
 379   else
 380     bytes = pt_var_size;
 381
 382   if (tree_fits_uhwi_p (bytes))
 383     return tree_to_uhwi (bytes);
 384
 385   return unknown[object_size_type];
 386 }
 387
 388
 389 /* Compute __builtin_object_size for CALL, which is a GIMPLE_CALL.
 390    Handles various allocation calls.  OBJECT_SIZE_TYPE is the second
 391    argument from __builtin_object_size.  If unknown, return
 392    unknown[object_size_type].  */
 393
 394 static unsigned HOST_WIDE_INT
 395 alloc_object_size (const_gimple call, int object_size_type)
 396 {
 397   tree callee, bytes = NULL_TREE;
 398   tree alloc_size;
 399   int arg1 = -1, arg2 = -1;
 400
 401   gcc_assert (is_gimple_call (call));
 402
 403   callee = gimple_call_fndecl (call);
 404   if (!callee)
 405     return unknown[object_size_type];
 406
 407   alloc_size = lookup_attribute ("alloc_size",
 408                                  TYPE_ATTRIBUTES (TREE_TYPE (callee)));
 409   if (alloc_size && TREE_VALUE (alloc_size))
 410     {
 411       tree p = TREE_VALUE (alloc_size);
 412
 413       arg1 = TREE_INT_CST_LOW (TREE_VALUE (p))-1;
 414       if (TREE_CHAIN (p))
 415         arg2 = TREE_INT_CST_LOW (TREE_VALUE (TREE_CHAIN (p)))-1;
 416     }
 417
 418   if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
 419     switch (DECL_FUNCTION_CODE (callee))
 420       {
 421       case BUILT_IN_CALLOC:
 422         arg2 = 1;
 423         /* fall through */
 424       case BUILT_IN_MALLOC:
 425       case BUILT_IN_ALLOCA:
 426       case BUILT_IN_ALLOCA_WITH_ALIGN:
 427         arg1 = 0;
 428       default:
 429         break;
 430       }
 431
 432   if (arg1 < 0 || arg1 >= (int)gimple_call_num_args (call)
 433       || TREE_CODE (gimple_call_arg (call, arg1)) != INTEGER_CST
 434       || (arg2 >= 0
 435           && (arg2 >= (int)gimple_call_num_args (call)
 436               || TREE_CODE (gimple_call_arg (call, arg2)) != INTEGER_CST)))
 437     return unknown[object_size_type];
 438
 439   if (arg2 >= 0)
 440     bytes = size_binop (MULT_EXPR,
 441         fold_convert (sizetype, gimple_call_arg (call, arg1)),
 442         fold_convert (sizetype, gimple_call_arg (call, arg2)));
 443   else if (arg1 >= 0)
 444     bytes = fold_convert (sizetype, gimple_call_arg (call, arg1));
 445
 446   if (bytes && tree_fits_uhwi_p (bytes))
 447     return tree_to_uhwi (bytes);
 448
 449   return unknown[object_size_type];
 450 }
 451
 452
 453 /* If object size is propagated from one of function's arguments directly
 454    to its return value, return that argument for GIMPLE_CALL statement CALL.
 455    Otherwise return NULL.  */
 456
 457 static tree
 458 pass_through_call (const_gimple call)
 459 {
 460   tree callee = gimple_call_fndecl (call);
 461
 462   if (callee
 463       && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
 464     switch (DECL_FUNCTION_CODE (callee))
 465       {
 466       case BUILT_IN_MEMCPY:
 467       case BUILT_IN_MEMMOVE:
 468       case BUILT_IN_MEMSET:
 469       case BUILT_IN_STRCPY:
 470       case BUILT_IN_STRNCPY:
 471       case BUILT_IN_STRCAT:
 472       case BUILT_IN_STRNCAT:
 473       case BUILT_IN_MEMCPY_CHK:
 474       case BUILT_IN_MEMMOVE_CHK:
 475       case BUILT_IN_MEMSET_CHK:
 476       case BUILT_IN_STRCPY_CHK:
 477       case BUILT_IN_STRNCPY_CHK:
 478       case BUILT_IN_STPNCPY_CHK:
 479       case BUILT_IN_STRCAT_CHK:
 480       case BUILT_IN_STRNCAT_CHK:
 481       case BUILT_IN_ASSUME_ALIGNED:
 482         if (gimple_call_num_args (call) >= 1)
 483           return gimple_call_arg (call, 0);
 484         break;
 485       default:
 486         break;
 487       }
 488
 489   return NULL_TREE;
 490 }
 491
 492
 493 /* Compute __builtin_object_size value for PTR.  OBJECT_SIZE_TYPE is the
 494    second argument from __builtin_object_size.  */
 495
 496 unsigned HOST_WIDE_INT
 497 compute_builtin_object_size (tree ptr, int object_size_type)
 498 {
 499   gcc_assert (object_size_type >= 0 && object_size_type <= 3);
 500
 501   if (! offset_limit)
 502     init_offset_limit ();
 503
 504   if (TREE_CODE (ptr) == ADDR_EXPR)
 505     return addr_object_size (NULL, ptr, object_size_type);
 506
 507   if (TREE_CODE (ptr) == SSA_NAME
 508       && POINTER_TYPE_P (TREE_TYPE (ptr))
 509       && computed[object_size_type] != NULL)
 510     {
 511       if (!bitmap_bit_p (computed[object_size_type], SSA_NAME_VERSION (ptr)))
 512         {
 513           struct object_size_info osi;
 514           bitmap_iterator bi;
 515           unsigned int i;
 516
 517           if (num_ssa_names > object_sizes[object_size_type].length ())
 518             object_sizes[object_size_type].safe_grow (num_ssa_names);
 519           if (dump_file)
 520             {
 521               fprintf (dump_file, "Computing %s %sobject size for ",
 522                        (object_size_type & 2) ? "minimum" : "maximum",
 523                        (object_size_type & 1) ? "sub" : "");
 524               print_generic_expr (dump_file, ptr, dump_flags);
 525               fprintf (dump_file, ":\n");
 526             }
 527
 528           osi.visited = BITMAP_ALLOC (NULL);
 529           osi.reexamine = BITMAP_ALLOC (NULL);
 530           osi.object_size_type = object_size_type;
 531           osi.depths = NULL;
 532           osi.stack = NULL;
 533           osi.tos = NULL;
 534
 535           /* First pass: walk UD chains, compute object sizes that
 536              can be computed.  osi.reexamine bitmap at the end will
 537              contain what variables were found in dependency cycles
 538              and therefore need to be reexamined.  */
 539           osi.pass = 0;
 540           osi.changed = false;
 541           collect_object_sizes_for (&osi, ptr);
 542
 543           /* Second pass: keep recomputing object sizes of variables
 544              that need reexamination, until no object sizes are
 545              increased or all object sizes are computed.  */
 546           if (! bitmap_empty_p (osi.reexamine))
 547             {
 548               bitmap reexamine = BITMAP_ALLOC (NULL);
 549
 550               /* If looking for minimum instead of maximum object size,
 551                  detect cases where a pointer is increased in a loop.
 552                  Although even without this detection pass 2 would eventually
 553                  terminate, it could take a long time.  If a pointer is
 554                  increasing this way, we need to assume 0 object size.
 555                  E.g. p = &buf[0]; while (cond) p = p + 4;  */
 556               if (object_size_type & 2)
 557                 {
 558                   osi.depths = XCNEWVEC (unsigned int, num_ssa_names);
 559                   osi.stack = XNEWVEC (unsigned int, num_ssa_names);
 560                   osi.tos = osi.stack;
 561                   osi.pass = 1;
 562                   /* collect_object_sizes_for is changing
 563                      osi.reexamine bitmap, so iterate over a copy.  */
 564                   bitmap_copy (reexamine, osi.reexamine);
 565                   EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi)
 566                     if (bitmap_bit_p (osi.reexamine, i))
 567                       check_for_plus_in_loops (&osi, ssa_name (i));
 568
 569                   free (osi.depths);
 570                   osi.depths = NULL;
 571                   free (osi.stack);
 572                   osi.stack = NULL;
 573                   osi.tos = NULL;
 574                 }
 575
 576               do
 577                 {
 578                   osi.pass = 2;
 579                   osi.changed = false;
 580                   /* collect_object_sizes_for is changing
 581                      osi.reexamine bitmap, so iterate over a copy.  */
 582                   bitmap_copy (reexamine, osi.reexamine);
 583                   EXECUTE_IF_SET_IN_BITMAP (reexamine, 0, i, bi)
 584                     if (bitmap_bit_p (osi.reexamine, i))
 585                       {
 586                         collect_object_sizes_for (&osi, ssa_name (i));
 587                         if (dump_file && (dump_flags & TDF_DETAILS))
 588                           {
 589                             fprintf (dump_file, "Reexamining ");
 590                             print_generic_expr (dump_file, ssa_name (i),
 591                                                 dump_flags);
 592                             fprintf (dump_file, "\n");
 593                           }
 594                       }
 595                 }
 596               while (osi.changed);
 597
 598               BITMAP_FREE (reexamine);
 599             }
 600           EXECUTE_IF_SET_IN_BITMAP (osi.reexamine, 0, i, bi)
 601             bitmap_set_bit (computed[object_size_type], i);
 602
 603           /* Debugging dumps.  */
 604           if (dump_file)
 605             {
 606               EXECUTE_IF_SET_IN_BITMAP (osi.visited, 0, i, bi)
 607                 if (object_sizes[object_size_type][i]
 608                     != unknown[object_size_type])
 609                   {
 610                     print_generic_expr (dump_file, ssa_name (i),
 611                                         dump_flags);
 612                     fprintf (dump_file,
 613                              ": %s %sobject size "
 614                              HOST_WIDE_INT_PRINT_UNSIGNED "\n",
 615                              (object_size_type & 2) ? "minimum" : "maximum",
 616                              (object_size_type & 1) ? "sub" : "",
 617                              object_sizes[object_size_type][i]);
 618                   }
 619             }
 620
 621           BITMAP_FREE (osi.reexamine);
 622           BITMAP_FREE (osi.visited);
 623         }
 624
 625       return object_sizes[object_size_type][SSA_NAME_VERSION (ptr)];
 626     }
 627
 628   return unknown[object_size_type];
 629 }
 630
 631 /* Compute object_sizes for PTR, defined to VALUE, which is not an SSA_NAME.  */
 632
 633 static void
 634 expr_object_size (struct object_size_info *osi, tree ptr, tree value)
 635 {
 636   int object_size_type = osi->object_size_type;
 637   unsigned int varno = SSA_NAME_VERSION (ptr);
 638   unsigned HOST_WIDE_INT bytes;
 639
 640   gcc_assert (object_sizes[object_size_type][varno]
 641               != unknown[object_size_type]);
 642   gcc_assert (osi->pass == 0);
 643
 644   if (TREE_CODE (value) == WITH_SIZE_EXPR)
 645     value = TREE_OPERAND (value, 0);
 646
 647   /* Pointer variables should have been handled by merge_object_sizes.  */
 648   gcc_assert (TREE_CODE (value) != SSA_NAME
 649               || !POINTER_TYPE_P (TREE_TYPE (value)));
 650
 651   if (TREE_CODE (value) == ADDR_EXPR)
 652     bytes = addr_object_size (osi, value, object_size_type);
 653   else
 654     bytes = unknown[object_size_type];
 655
 656   if ((object_size_type & 2) == 0)
 657     {
 658       if (object_sizes[object_size_type][varno] < bytes)
 659         object_sizes[object_size_type][varno] = bytes;
 660     }
 661   else
 662     {
 663       if (object_sizes[object_size_type][varno] > bytes)
 664         object_sizes[object_size_type][varno] = bytes;
 665     }
 666 }
 667
 668
 669 /* Compute object_sizes for PTR, defined to the result of a call.  */
 670
 671 static void
 672 call_object_size (struct object_size_info *osi, tree ptr, gimple call)
 673 {
 674   int object_size_type = osi->object_size_type;
 675   unsigned int varno = SSA_NAME_VERSION (ptr);
 676   unsigned HOST_WIDE_INT bytes;
 677
 678   gcc_assert (is_gimple_call (call));
 679
 680   gcc_assert (object_sizes[object_size_type][varno]
 681               != unknown[object_size_type]);
 682   gcc_assert (osi->pass == 0);
 683
 684   bytes = alloc_object_size (call, object_size_type);
 685
 686   if ((object_size_type & 2) == 0)
 687     {
 688       if (object_sizes[object_size_type][varno] < bytes)
 689         object_sizes[object_size_type][varno] = bytes;
 690     }
 691   else
 692     {
 693       if (object_sizes[object_size_type][varno] > bytes)
 694         object_sizes[object_size_type][varno] = bytes;
 695     }
 696 }
 697
 698
 699 /* Compute object_sizes for PTR, defined to an unknown value.  */
 700
 701 static void
 702 unknown_object_size (struct object_size_info *osi, tree ptr)
 703 {
 704   int object_size_type = osi->object_size_type;
 705   unsigned int varno = SSA_NAME_VERSION (ptr);
 706   unsigned HOST_WIDE_INT bytes;
 707
 708   gcc_assert (object_sizes[object_size_type][varno]
 709               != unknown[object_size_type]);
 710   gcc_assert (osi->pass == 0);
 711
 712   bytes = unknown[object_size_type];
 713
 714   if ((object_size_type & 2) == 0)
 715     {
 716       if (object_sizes[object_size_type][varno] < bytes)
 717         object_sizes[object_size_type][varno] = bytes;
 718     }
 719   else
 720     {
 721       if (object_sizes[object_size_type][varno] > bytes)
 722         object_sizes[object_size_type][varno] = bytes;
 723     }
 724 }
 725
 726
 727 /* Merge object sizes of ORIG + OFFSET into DEST.  Return true if
 728    the object size might need reexamination later.  */
 729
 730 static bool
 731 merge_object_sizes (struct object_size_info *osi, tree dest, tree orig,
 732                     unsigned HOST_WIDE_INT offset)
 733 {
 734   int object_size_type = osi->object_size_type;
 735   unsigned int varno = SSA_NAME_VERSION (dest);
 736   unsigned HOST_WIDE_INT orig_bytes;
 737
 738   if (object_sizes[object_size_type][varno] == unknown[object_size_type])
 739     return false;
 740   if (offset >= offset_limit)
 741     {
 742       object_sizes[object_size_type][varno] = unknown[object_size_type];
 743       return false;
 744     }
 745
 746   if (osi->pass == 0)
 747     collect_object_sizes_for (osi, orig);
 748
 749   orig_bytes = object_sizes[object_size_type][SSA_NAME_VERSION (orig)];
 750   if (orig_bytes != unknown[object_size_type])
 751     orig_bytes = (offset > orig_bytes)
 752                  ? (unsigned HOST_WIDE_INT) 0 : orig_bytes - offset;
 753
 754   if ((object_size_type & 2) == 0)
 755     {
 756       if (object_sizes[object_size_type][varno] < orig_bytes)
 757         {
 758           object_sizes[object_size_type][varno] = orig_bytes;
 759           osi->changed = true;
 760         }
 761     }
 762   else
 763     {
 764       if (object_sizes[object_size_type][varno] > orig_bytes)
 765         {
 766           object_sizes[object_size_type][varno] = orig_bytes;
 767           osi->changed = true;
 768         }
 769     }
 770   return bitmap_bit_p (osi->reexamine, SSA_NAME_VERSION (orig));
 771 }
 772
 773
 774 /* Compute object_sizes for VAR, defined to the result of an assignment
 775    with operator POINTER_PLUS_EXPR.  Return true if the object size might
 776    need reexamination  later.  */
 777
 778 static bool
 779 plus_stmt_object_size (struct object_size_info *osi, tree var, gimple stmt)
 780 {
 781   int object_size_type = osi->object_size_type;
 782   unsigned int varno = SSA_NAME_VERSION (var);
 783   unsigned HOST_WIDE_INT bytes;
 784   tree op0, op1;
 785
 786   if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
 787     {
 788       op0 = gimple_assign_rhs1 (stmt);
 789       op1 = gimple_assign_rhs2 (stmt);
 790     }
 791   else if (gimple_assign_rhs_code (stmt) == ADDR_EXPR)
 792     {
 793       tree rhs = TREE_OPERAND (gimple_assign_rhs1 (stmt), 0);
 794       gcc_assert (TREE_CODE (rhs) == MEM_REF);
 795       op0 = TREE_OPERAND (rhs, 0);
 796       op1 = TREE_OPERAND (rhs, 1);
 797     }
 798   else
 799     gcc_unreachable ();
 800
 801   if (object_sizes[object_size_type][varno] == unknown[object_size_type])
 802     return false;
 803
 804   /* Handle PTR + OFFSET here.  */
 805   if (TREE_CODE (op1) == INTEGER_CST
 806       && (TREE_CODE (op0) == SSA_NAME
 807           || TREE_CODE (op0) == ADDR_EXPR))
 808     {
 809       if (! tree_fits_uhwi_p (op1))
 810         bytes = unknown[object_size_type];
 811       else if (TREE_CODE (op0) == SSA_NAME)
 812         return merge_object_sizes (osi, var, op0, tree_to_uhwi (op1));
 813       else
 814         {
 815           unsigned HOST_WIDE_INT off = tree_to_uhwi (op1);
 816
 817           /* op0 will be ADDR_EXPR here.  */
 818           bytes = addr_object_size (osi, op0, object_size_type);
 819           if (bytes == unknown[object_size_type])
 820             ;
 821           else if (off > offset_limit)
 822             bytes = unknown[object_size_type];
 823           else if (off > bytes)
 824             bytes = 0;
 825           else
 826             bytes -= off;
 827         }
 828     }
 829   else
 830     bytes = unknown[object_size_type];
 831
 832   if ((object_size_type & 2) == 0)
 833     {
 834       if (object_sizes[object_size_type][varno] < bytes)
 835         object_sizes[object_size_type][varno] = bytes;
 836     }
 837   else
 838     {
 839       if (object_sizes[object_size_type][varno] > bytes)
 840         object_sizes[object_size_type][varno] = bytes;
 841     }
 842   return false;
 843 }
 844
 845
 846 /* Compute object_sizes for VAR, defined at STMT, which is
 847    a COND_EXPR.  Return true if the object size might need reexamination
 848    later.  */
 849
 850 static bool
 851 cond_expr_object_size (struct object_size_info *osi, tree var, gimple stmt)
 852 {
 853   tree then_, else_;
 854   int object_size_type = osi->object_size_type;
 855   unsigned int varno = SSA_NAME_VERSION (var);
 856   bool reexamine = false;
 857
 858   gcc_assert (gimple_assign_rhs_code (stmt) == COND_EXPR);
 859
 860   if (object_sizes[object_size_type][varno] == unknown[object_size_type])
 861     return false;
 862
 863   then_ = gimple_assign_rhs2 (stmt);
 864   else_ = gimple_assign_rhs3 (stmt);
 865
 866   if (TREE_CODE (then_) == SSA_NAME)
 867     reexamine |= merge_object_sizes (osi, var, then_, 0);
 868   else
 869     expr_object_size (osi, var, then_);
 870
 871   if (TREE_CODE (else_) == SSA_NAME)
 872     reexamine |= merge_object_sizes (osi, var, else_, 0);
 873   else
 874     expr_object_size (osi, var, else_);
 875
 876   return reexamine;
 877 }
 878
 879 /* Compute object sizes for VAR.
 880    For ADDR_EXPR an object size is the number of remaining bytes
 881    to the end of the object (where what is considered an object depends on
 882    OSI->object_size_type).
 883    For allocation GIMPLE_CALL like malloc or calloc object size is the size
 884    of the allocation.
 885    For POINTER_PLUS_EXPR where second operand is a constant integer,
 886    object size is object size of the first operand minus the constant.
 887    If the constant is bigger than the number of remaining bytes until the
 888    end of the object, object size is 0, but if it is instead a pointer
 889    subtraction, object size is unknown[object_size_type].
 890    To differentiate addition from subtraction, ADDR_EXPR returns
 891    unknown[object_size_type] for all objects bigger than half of the address
 892    space, and constants less than half of the address space are considered
 893    addition, while bigger constants subtraction.
 894    For a memcpy like GIMPLE_CALL that always returns one of its arguments, the
 895    object size is object size of that argument.
 896    Otherwise, object size is the maximum of object sizes of variables
 897    that it might be set to.  */
 898
 899 static void
 900 collect_object_sizes_for (struct object_size_info *osi, tree var)
 901 {
 902   int object_size_type = osi->object_size_type;
 903   unsigned int varno = SSA_NAME_VERSION (var);
 904   gimple stmt;
 905   bool reexamine;
 906
 907   if (bitmap_bit_p (computed[object_size_type], varno))
 908     return;
 909
 910   if (osi->pass == 0)
 911     {
 912       if (bitmap_set_bit (osi->visited, varno))
 913         {
 914           object_sizes[object_size_type][varno]
 915             = (object_size_type & 2) ? -1 : 0;
 916         }
 917       else
 918         {
 919           /* Found a dependency loop.  Mark the variable for later
 920              re-examination.  */
 921           bitmap_set_bit (osi->reexamine, varno);
 922           if (dump_file && (dump_flags & TDF_DETAILS))
 923             {
 924               fprintf (dump_file, "Found a dependency loop at ");
 925               print_generic_expr (dump_file, var, dump_flags);
 926               fprintf (dump_file, "\n");
 927             }
 928           return;
 929         }
 930     }
 931
 932   if (dump_file && (dump_flags & TDF_DETAILS))
 933     {
 934       fprintf (dump_file, "Visiting use-def links for ");
 935       print_generic_expr (dump_file, var, dump_flags);
 936       fprintf (dump_file, "\n");
 937     }
 938
 939   stmt = SSA_NAME_DEF_STMT (var);
 940   reexamine = false;
 941
 942   switch (gimple_code (stmt))
 943     {
 944     case GIMPLE_ASSIGN:
 945       {
 946         tree rhs = gimple_assign_rhs1 (stmt);
 947         if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
 948             || (gimple_assign_rhs_code (stmt) == ADDR_EXPR
 949                 && TREE_CODE (TREE_OPERAND (rhs, 0)) == MEM_REF))
 950           reexamine = plus_stmt_object_size (osi, var, stmt);
 951         else if (gimple_assign_rhs_code (stmt) == COND_EXPR)
 952           reexamine = cond_expr_object_size (osi, var, stmt);
 953         else if (gimple_assign_single_p (stmt)
 954                  || gimple_assign_unary_nop_p (stmt))
 955           {
 956             if (TREE_CODE (rhs) == SSA_NAME
 957                 && POINTER_TYPE_P (TREE_TYPE (rhs)))
 958               reexamine = merge_object_sizes (osi, var, rhs, 0);
 959             else
 960               expr_object_size (osi, var, rhs);
 961           }
 962         else
 963           unknown_object_size (osi, var);
 964         break;
 965       }
 966
 967     case GIMPLE_CALL:
 968       {
 969         tree arg = pass_through_call (stmt);
 970         if (arg)
 971           {
 972             if (TREE_CODE (arg) == SSA_NAME
 973                 && POINTER_TYPE_P (TREE_TYPE (arg)))
 974               reexamine = merge_object_sizes (osi, var, arg, 0);
 975             else
 976               expr_object_size (osi, var, arg);
 977           }
 978         else
 979           call_object_size (osi, var, stmt);
 980         break;
 981       }
 982
 983     case GIMPLE_ASM:
 984       /* Pointers defined by __asm__ statements can point anywhere.  */
 985       object_sizes[object_size_type][varno] = unknown[object_size_type];
 986       break;
 987
 988     case GIMPLE_NOP:
 989       if (SSA_NAME_VAR (var)
 990           && TREE_CODE (SSA_NAME_VAR (var)) == PARM_DECL)
 991         expr_object_size (osi, var, SSA_NAME_VAR (var));
 992       else
 993         /* Uninitialized SSA names point nowhere.  */
 994         object_sizes[object_size_type][varno] = unknown[object_size_type];
 995       break;
 996
 997     case GIMPLE_PHI:
 998       {
 999         unsigned i;
1000
1001         for (i = 0; i < gimple_phi_num_args (stmt); i++)
1002           {
1003             tree rhs = gimple_phi_arg (stmt, i)->def;
1004
1005             if (object_sizes[object_size_type][varno]
1006                 == unknown[object_size_type])
1007               break;
1008
1009             if (TREE_CODE (rhs) == SSA_NAME)
1010               reexamine |= merge_object_sizes (osi, var, rhs, 0);
1011             else if (osi->pass == 0)
1012               expr_object_size (osi, var, rhs);
1013           }
1014         break;
1015       }
1016
1017     default:
1018       gcc_unreachable ();
1019     }
1020
1021   if (! reexamine
1022       || object_sizes[object_size_type][varno] == unknown[object_size_type])
1023     {
1024       bitmap_set_bit (computed[object_size_type], varno);
1025       bitmap_clear_bit (osi->reexamine, varno);
1026     }
1027   else
1028     {
1029       bitmap_set_bit (osi->reexamine, varno);
1030       if (dump_file && (dump_flags & TDF_DETAILS))
1031         {
1032           fprintf (dump_file, "Need to reexamine ");
1033           print_generic_expr (dump_file, var, dump_flags);
1034           fprintf (dump_file, "\n");
1035         }
1036     }
1037 }
1038
1039
1040 /* Helper function for check_for_plus_in_loops.  Called recursively
1041    to detect loops.  */
1042
1043 static void
1044 check_for_plus_in_loops_1 (struct object_size_info *osi, tree var,
1045                            unsigned int depth)
1046 {
1047   gimple stmt = SSA_NAME_DEF_STMT (var);
1048   unsigned int varno = SSA_NAME_VERSION (var);
1049
1050   if (osi->depths[varno])
1051     {
1052       if (osi->depths[varno] != depth)
1053         {
1054           unsigned int *sp;
1055
1056           /* Found a loop involving pointer addition.  */
1057           for (sp = osi->tos; sp > osi->stack; )
1058             {
1059               --sp;
1060               bitmap_clear_bit (osi->reexamine, *sp);
1061               bitmap_set_bit (computed[osi->object_size_type], *sp);
1062               object_sizes[osi->object_size_type][*sp] = 0;
1063               if (*sp == varno)
1064                 break;
1065             }
1066         }
1067       return;
1068     }
1069   else if (! bitmap_bit_p (osi->reexamine, varno))
1070     return;
1071
1072   osi->depths[varno] = depth;
1073   *osi->tos++ = varno;
1074
1075   switch (gimple_code (stmt))
1076     {
1077
1078     case GIMPLE_ASSIGN:
1079       {
1080         if ((gimple_assign_single_p (stmt)
1081              || gimple_assign_unary_nop_p (stmt))
1082             && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME)
1083           {
1084             tree rhs = gimple_assign_rhs1 (stmt);
1085
1086             check_for_plus_in_loops_1 (osi, rhs, depth);
1087           }
1088         else if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
1089           {
1090             tree basevar = gimple_assign_rhs1 (stmt);
1091             tree cst = gimple_assign_rhs2 (stmt);
1092
1093             gcc_assert (TREE_CODE (cst) == INTEGER_CST);
1094
1095             check_for_plus_in_loops_1 (osi, basevar,
1096                                        depth + !integer_zerop (cst));
1097           }
1098         else
1099           gcc_unreachable ();
1100         break;
1101       }
1102
1103     case GIMPLE_CALL:
1104       {
1105         tree arg = pass_through_call (stmt);
1106         if (arg)
1107           {
1108             if (TREE_CODE (arg) == SSA_NAME)
1109               check_for_plus_in_loops_1 (osi, arg, depth);
1110             else
1111               gcc_unreachable ();
1112           }
1113         break;
1114       }
1115
1116     case GIMPLE_PHI:
1117       {
1118         unsigned i;
1119
1120         for (i = 0; i < gimple_phi_num_args (stmt); i++)
1121           {
1122             tree rhs = gimple_phi_arg (stmt, i)->def;
1123
1124             if (TREE_CODE (rhs) == SSA_NAME)
1125               check_for_plus_in_loops_1 (osi, rhs, depth);
1126           }
1127         break;
1128       }
1129
1130     default:
1131       gcc_unreachable ();
1132     }
1133
1134   osi->depths[varno] = 0;
1135   osi->tos--;
1136 }
1137
1138
1139 /* Check if some pointer we are computing object size of is being increased
1140    within a loop.  If yes, assume all the SSA variables participating in
1141    that loop have minimum object sizes 0.  */
1142
1143 static void
1144 check_for_plus_in_loops (struct object_size_info *osi, tree var)
1145 {
1146   gimple stmt = SSA_NAME_DEF_STMT (var);
1147
1148   /* NOTE: In the pre-tuples code, we handled a CALL_EXPR here,
1149      and looked for a POINTER_PLUS_EXPR in the pass-through
1150      argument, if any.  In GIMPLE, however, such an expression
1151      is not a valid call operand.  */
1152
1153   if (is_gimple_assign (stmt)
1154       && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
1155     {
1156       tree basevar = gimple_assign_rhs1 (stmt);
1157       tree cst = gimple_assign_rhs2 (stmt);
1158
1159       gcc_assert (TREE_CODE (cst) == INTEGER_CST);
1160
1161       if (integer_zerop (cst))
1162         return;
1163
1164       osi->depths[SSA_NAME_VERSION (basevar)] = 1;
1165       *osi->tos++ = SSA_NAME_VERSION (basevar);
1166       check_for_plus_in_loops_1 (osi, var, 2);
1167       osi->depths[SSA_NAME_VERSION (basevar)] = 0;
1168       osi->tos--;
1169     }
1170 }
1171
1172
1173 /* Initialize data structures for the object size computation.  */
1174
1175 void
1176 init_object_sizes (void)
1177 {
1178   int object_size_type;
1179
1180   if (computed[0])
1181     return;
1182
1183   for (object_size_type = 0; object_size_type <= 3; object_size_type++)
1184     {
1185       object_sizes[object_size_type].safe_grow (num_ssa_names);
1186       computed[object_size_type] = BITMAP_ALLOC (NULL);
1187     }
1188
1189   init_offset_limit ();
1190 }
1191
1192
1193 /* Destroy data structures after the object size computation.  */
1194
1195 static void
1196 fini_object_sizes (void)
1197 {
1198   int object_size_type;
1199
1200   for (object_size_type = 0; object_size_type <= 3; object_size_type++)
1201     {
1202       object_sizes[object_size_type].release ();
1203       BITMAP_FREE (computed[object_size_type]);
1204     }
1205 }
1206
1207
1208 /* Simple pass to optimize all __builtin_object_size () builtins.  */
1209
1210 namespace {
1211
1212 const pass_data pass_data_object_sizes =
1213 {
1214   GIMPLE_PASS, /* type */
1215   "objsz", /* name */
1216   OPTGROUP_NONE, /* optinfo_flags */
1217   TV_NONE, /* tv_id */
1218   ( PROP_cfg | PROP_ssa ), /* properties_required */
1219   0, /* properties_provided */
1220   0, /* properties_destroyed */
1221   0, /* todo_flags_start */
1222   0, /* todo_flags_finish */
1223 };
1224
1225 class pass_object_sizes : public gimple_opt_pass
1226 {
1227 public:
1228   pass_object_sizes (gcc::context *ctxt)
1229     : gimple_opt_pass (pass_data_object_sizes, ctxt)
1230   {}
1231
1232   /* opt_pass methods: */
1233   opt_pass * clone () { return new pass_object_sizes (m_ctxt); }
1234   virtual unsigned int execute (function *);
1235
1236 }; // class pass_object_sizes
1237
1238 unsigned int
1239 pass_object_sizes::execute (function *fun)
1240 {
1241   basic_block bb;
1242   FOR_EACH_BB_FN (bb, fun)
1243     {
1244       gimple_stmt_iterator i;
1245       for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i))
1246         {
1247           tree result;
1248           gimple call = gsi_stmt (i);
1249           if (!gimple_call_builtin_p (call, BUILT_IN_OBJECT_SIZE))
1250             continue;
1251
1252           init_object_sizes ();
1253           result = fold_call_stmt (call, false);
1254           if (!result)
1255             {
1256               if (gimple_call_num_args (call) == 2
1257                   && POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0))))
1258                 {
1259                   tree ost = gimple_call_arg (call, 1);
1260
1261                   if (tree_fits_uhwi_p (ost))
1262                     {
1263                       unsigned HOST_WIDE_INT object_size_type
1264                         = tree_to_uhwi (ost);
1265
1266                       if (object_size_type < 2)
1267                         result = fold_convert (size_type_node,
1268                                                integer_minus_one_node);
1269                       else if (object_size_type < 4)
1270                         result = build_zero_cst (size_type_node);
1271                     }
1272                 }
1273
1274               if (!result)
1275                 continue;
1276             }
1277
1278           gcc_assert (TREE_CODE (result) == INTEGER_CST);
1279
1280           if (dump_file && (dump_flags & TDF_DETAILS))
1281             {
1282               fprintf (dump_file, "Simplified\n  ");
1283               print_gimple_stmt (dump_file, call, 0, dump_flags);
1284               fprintf (dump_file, " to ");
1285               print_generic_expr (dump_file, result, 0);
1286               fprintf (dump_file, "\n");
1287             }
1288
1289           tree lhs = gimple_call_lhs (call);
1290           if (!lhs)
1291             continue;
1292
1293           /* Propagate into all uses and fold those stmts.  */
1294           gimple use_stmt;
1295           imm_use_iterator iter;
1296           FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
1297             {
1298               use_operand_p use_p;
1299               FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
1300                 SET_USE (use_p, result);
1301               gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
1302               fold_stmt (&gsi);
1303               update_stmt (gsi_stmt (gsi));
1304             }
1305         }
1306     }
1307
1308   fini_object_sizes ();
1309   return 0;
1310 }
1311
1312 } // anon namespace
1313
1314 gimple_opt_pass *
1315 make_pass_object_sizes (gcc::context *ctxt)
1316 {
1317   return new pass_object_sizes (ctxt);
1318 }