gcc/lto-streamer.c

   1 /* Miscellaneous utilities for GIMPLE streaming.  Things that are used
   2    in both input and output are here.
   3
   4    Copyright 2009, 2010 Free Software Foundation, Inc.
   5    Contributed by Doug Kwan <dougkwan@google.com>
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify it under
  10 the terms of the GNU General Public License as published by the Free
  11 Software Foundation; either version 3, or (at your option) any later
  12 version.
  13
  14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17 for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING3.  If not see
  21 <http://www.gnu.org/licenses/>.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "tm.h"
  27 #include "toplev.h"
  28 #include "flags.h"
  29 #include "tree.h"
  30 #include "gimple.h"
  31 #include "tree-flow.h"
  32 #include "diagnostic-core.h"
  33 #include "bitmap.h"
  34 #include "vec.h"
  35 #include "lto-streamer.h"
  36
  37 /* Statistics gathered during LTO, WPA and LTRANS.  */
  38 struct lto_stats_d lto_stats;
  39
  40 /* LTO uses bitmaps with different life-times.  So use a seperate
  41    obstack for all LTO bitmaps.  */
  42 static bitmap_obstack lto_obstack;
  43 static bool lto_obstack_initialized;
  44
  45
  46 /* Return a string representing LTO tag TAG.  */
  47
  48 const char *
  49 lto_tag_name (enum LTO_tags tag)
  50 {
  51   if (lto_tag_is_tree_code_p (tag))
  52     {
  53       /* For tags representing tree nodes, return the name of the
  54          associated tree code.  */
  55       return tree_code_name[lto_tag_to_tree_code (tag)];
  56     }
  57
  58   if (lto_tag_is_gimple_code_p (tag))
  59     {
  60       /* For tags representing gimple statements, return the name of
  61          the associated gimple code.  */
  62       return gimple_code_name[lto_tag_to_gimple_code (tag)];
  63     }
  64
  65   switch (tag)
  66     {
  67     case LTO_null:
  68       return "LTO_null";
  69     case LTO_bb0:
  70       return "LTO_bb0";
  71     case LTO_bb1:
  72       return "LTO_bb1";
  73     case LTO_eh_region:
  74       return "LTO_eh_region";
  75     case LTO_function:
  76       return "LTO_function";
  77     case LTO_eh_table:
  78       return "LTO_eh_table";
  79     case LTO_ert_cleanup:
  80       return "LTO_ert_cleanup";
  81     case LTO_ert_try:
  82       return "LTO_ert_try";
  83     case LTO_ert_allowed_exceptions:
  84       return "LTO_ert_allowed_exceptions";
  85     case LTO_ert_must_not_throw:
  86       return "LTO_ert_must_not_throw";
  87     case LTO_tree_pickle_reference:
  88       return "LTO_tree_pickle_reference";
  89     case LTO_field_decl_ref:
  90       return "LTO_field_decl_ref";
  91     case LTO_function_decl_ref:
  92       return "LTO_function_decl_ref";
  93     case LTO_label_decl_ref:
  94       return "LTO_label_decl_ref";
  95     case LTO_namespace_decl_ref:
  96       return "LTO_namespace_decl_ref";
  97     case LTO_result_decl_ref:
  98       return "LTO_result_decl_ref";
  99     case LTO_ssa_name_ref:
 100       return "LTO_ssa_name_ref";
 101     case LTO_type_decl_ref:
 102       return "LTO_type_decl_ref";
 103     case LTO_type_ref:
 104       return "LTO_type_ref";
 105     case LTO_global_decl_ref:
 106       return "LTO_global_decl_ref";
 107     default:
 108       return "LTO_UNKNOWN";
 109     }
 110 }
 111
 112
 113 /* Allocate a bitmap from heap.  Initializes the LTO obstack if necessary.  */
 114
 115 bitmap
 116 lto_bitmap_alloc (void)
 117 {
 118   if (!lto_obstack_initialized)
 119     {
 120       bitmap_obstack_initialize (&lto_obstack);
 121       lto_obstack_initialized = true;
 122     }
 123   return BITMAP_ALLOC (&lto_obstack);
 124 }
 125
 126 /* Free bitmap B.  */
 127
 128 void
 129 lto_bitmap_free (bitmap b)
 130 {
 131   BITMAP_FREE (b);
 132 }
 133
 134
 135 /* Get a section name for a particular type or name.  The NAME field
 136    is only used if SECTION_TYPE is LTO_section_function_body. For all
 137    others it is ignored.  The callee of this function is responsible
 138    to free the returned name.  */
 139
 140 char *
 141 lto_get_section_name (int section_type, const char *name, struct lto_file_decl_data *f)
 142 {
 143   const char *add;
 144   char post[32];
 145   const char *sep;
 146
 147   if (section_type == LTO_section_function_body)
 148     {
 149       gcc_assert (name != NULL);
 150       if (name[0] == '*')
 151         name++;
 152       add = name;
 153       sep = "";
 154     }
 155   else if (section_type < LTO_N_SECTION_TYPES)
 156     {
 157       add = lto_section_name[section_type];
 158       sep = ".";
 159     }
 160   else
 161     internal_error ("bytecode stream: unexpected LTO section %s", name);
 162
 163   /* Make the section name unique so that ld -r combining sections
 164      doesn't confuse the reader with merged sections.
 165
 166      For options don't add a ID, the option reader cannot deal with them
 167      and merging should be ok here.
 168
 169      XXX: use crc64 to minimize collisions? */
 170   if (section_type == LTO_section_opts)
 171     strcpy (post, "");
 172   else
 173     sprintf (post, ".%x", f ? f->id : crc32_string(0, get_random_seed (false)));
 174   return concat (LTO_SECTION_NAME_PREFIX, sep, add, post, NULL);
 175 }
 176
 177
 178 /* Show various memory usage statistics related to LTO.  */
 179
 180 void
 181 print_lto_report (void)
 182 {
 183   const char *s = (flag_lto) ? "LTO" : (flag_wpa) ? "WPA" : "LTRANS";
 184   unsigned i;
 185
 186   fprintf (stderr, "%s statistics\n", s);
 187   fprintf (stderr, "[%s] # of input files: "
 188            HOST_WIDE_INT_PRINT_UNSIGNED "\n", s, lto_stats.num_input_files);
 189
 190   fprintf (stderr, "[%s] # of input cgraph nodes: "
 191            HOST_WIDE_INT_PRINT_UNSIGNED "\n", s,
 192            lto_stats.num_input_cgraph_nodes);
 193
 194   fprintf (stderr, "[%s] # of function bodies: "
 195            HOST_WIDE_INT_PRINT_UNSIGNED "\n", s,
 196            lto_stats.num_function_bodies);
 197
 198   fprintf (stderr, "[%s] ", s);
 199   print_gimple_types_stats ();
 200
 201   for (i = 0; i < NUM_TREE_CODES; i++)
 202     if (lto_stats.num_trees[i])
 203       fprintf (stderr, "[%s] # of '%s' objects read: "
 204                HOST_WIDE_INT_PRINT_UNSIGNED "\n", s,
 205                tree_code_name[i], lto_stats.num_trees[i]);
 206
 207   if (flag_lto)
 208     {
 209       fprintf (stderr, "[%s] Compression: "
 210                HOST_WIDE_INT_PRINT_UNSIGNED " output bytes, "
 211                HOST_WIDE_INT_PRINT_UNSIGNED " compressed bytes", s,
 212                lto_stats.num_output_il_bytes,
 213                lto_stats.num_compressed_il_bytes);
 214       if (lto_stats.num_output_il_bytes > 0)
 215         {
 216           const float dividend = (float) lto_stats.num_compressed_il_bytes;
 217           const float divisor = (float) lto_stats.num_output_il_bytes;
 218           fprintf (stderr, " (ratio: %f)", dividend / divisor);
 219         }
 220       fprintf (stderr, "\n");
 221     }
 222
 223   if (flag_wpa)
 224     {
 225       fprintf (stderr, "[%s] # of output files: "
 226                HOST_WIDE_INT_PRINT_UNSIGNED "\n", s,
 227                lto_stats.num_output_files);
 228
 229       fprintf (stderr, "[%s] # of output cgraph nodes: "
 230                HOST_WIDE_INT_PRINT_UNSIGNED "\n", s,
 231                lto_stats.num_output_cgraph_nodes);
 232
 233       fprintf (stderr, "[%s] # callgraph partitions: "
 234                HOST_WIDE_INT_PRINT_UNSIGNED "\n", s,
 235                lto_stats.num_cgraph_partitions);
 236
 237       fprintf (stderr, "[%s] Compression: "
 238                HOST_WIDE_INT_PRINT_UNSIGNED " input bytes, "
 239                HOST_WIDE_INT_PRINT_UNSIGNED " uncompressed bytes", s,
 240                lto_stats.num_input_il_bytes,
 241                lto_stats.num_uncompressed_il_bytes);
 242       if (lto_stats.num_input_il_bytes > 0)
 243         {
 244           const float dividend = (float) lto_stats.num_uncompressed_il_bytes;
 245           const float divisor = (float) lto_stats.num_input_il_bytes;
 246           fprintf (stderr, " (ratio: %f)", dividend / divisor);
 247         }
 248       fprintf (stderr, "\n");
 249     }
 250
 251   for (i = 0; i < LTO_N_SECTION_TYPES; i++)
 252     fprintf (stderr, "[%s] Size of mmap'd section %s: "
 253              HOST_WIDE_INT_PRINT_UNSIGNED " bytes\n", s,
 254              lto_section_name[i], lto_stats.section_size[i]);
 255 }
 256
 257
 258 /* Check that all the TS_* structures handled by the lto_output_* and
 259    lto_input_* routines are exactly ALL the structures defined in
 260    treestruct.def.  */
 261
 262 static void
 263 check_handled_ts_structures (void)
 264 {
 265   bool handled_p[LAST_TS_ENUM];
 266   unsigned i;
 267
 268   memset (&handled_p, 0, sizeof (handled_p));
 269
 270   /* These are the TS_* structures that are either handled or
 271      explicitly ignored by the streamer routines.  */
 272   handled_p[TS_BASE] = true;
 273   handled_p[TS_COMMON] = true;
 274   handled_p[TS_INT_CST] = true;
 275   handled_p[TS_REAL_CST] = true;
 276   handled_p[TS_FIXED_CST] = true;
 277   handled_p[TS_VECTOR] = true;
 278   handled_p[TS_STRING] = true;
 279   handled_p[TS_COMPLEX] = true;
 280   handled_p[TS_IDENTIFIER] = true;
 281   handled_p[TS_DECL_MINIMAL] = true;
 282   handled_p[TS_DECL_COMMON] = true;
 283   handled_p[TS_DECL_WRTL] = true;
 284   handled_p[TS_DECL_NON_COMMON] = true;
 285   handled_p[TS_DECL_WITH_VIS] = true;
 286   handled_p[TS_FIELD_DECL] = true;
 287   handled_p[TS_VAR_DECL] = true;
 288   handled_p[TS_PARM_DECL] = true;
 289   handled_p[TS_LABEL_DECL] = true;
 290   handled_p[TS_RESULT_DECL] = true;
 291   handled_p[TS_CONST_DECL] = true;
 292   handled_p[TS_TYPE_DECL] = true;
 293   handled_p[TS_FUNCTION_DECL] = true;
 294   handled_p[TS_TYPE] = true;
 295   handled_p[TS_LIST] = true;
 296   handled_p[TS_VEC] = true;
 297   handled_p[TS_EXP] = true;
 298   handled_p[TS_SSA_NAME] = true;
 299   handled_p[TS_BLOCK] = true;
 300   handled_p[TS_BINFO] = true;
 301   handled_p[TS_STATEMENT_LIST] = true;
 302   handled_p[TS_CONSTRUCTOR] = true;
 303   handled_p[TS_OMP_CLAUSE] = true;
 304   handled_p[TS_OPTIMIZATION] = true;
 305   handled_p[TS_TARGET_OPTION] = true;
 306   handled_p[TS_TRANSLATION_UNIT_DECL] = true;
 307
 308   /* Anything not marked above will trigger the following assertion.
 309      If this assertion triggers, it means that there is a new TS_*
 310      structure that should be handled by the streamer.  */
 311   for (i = 0; i < LAST_TS_ENUM; i++)
 312     gcc_assert (handled_p[i]);
 313 }
 314
 315
 316 /* Helper for lto_streamer_cache_insert_1.  Add T to CACHE->NODES at
 317    slot IX.  Add OFFSET to CACHE->OFFSETS at slot IX.  */
 318
 319 static void
 320 lto_streamer_cache_add_to_node_array (struct lto_streamer_cache_d *cache,
 321                                       int ix, tree t, unsigned offset)
 322 {
 323   gcc_assert (ix >= 0);
 324
 325   /* Grow the array of nodes and offsets to accomodate T at IX.  */
 326   if (ix >= (int) VEC_length (tree, cache->nodes))
 327     {
 328       size_t sz = ix + (20 + ix) / 4;
 329       VEC_safe_grow_cleared (tree, heap, cache->nodes, sz);
 330       VEC_safe_grow_cleared (unsigned, heap, cache->offsets, sz);
 331     }
 332
 333   VEC_replace (tree, cache->nodes, ix, t);
 334   VEC_replace (unsigned, cache->offsets, ix, offset);
 335 }
 336
 337
 338 /* Helper for lto_streamer_cache_insert and lto_streamer_cache_insert_at.
 339    CACHE, T, IX_P and OFFSET_P are as in lto_streamer_cache_insert.
 340
 341    If INSERT_AT_NEXT_SLOT_P is true, T is inserted at the next available
 342    slot in the cache.  Otherwise, T is inserted at the position indicated
 343    in *IX_P.
 344
 345    If T already existed in CACHE, return true.  Otherwise,
 346    return false.  */
 347
 348 static bool
 349 lto_streamer_cache_insert_1 (struct lto_streamer_cache_d *cache,
 350                              tree t, int *ix_p, unsigned *offset_p,
 351                              bool insert_at_next_slot_p)
 352 {
 353   void **slot;
 354   struct tree_int_map d_entry, *entry;
 355   int ix;
 356   unsigned offset;
 357   bool existed_p;
 358
 359   gcc_assert (t);
 360
 361   d_entry.base.from = t;
 362   slot = htab_find_slot (cache->node_map, &d_entry, INSERT);
 363   if (*slot == NULL)
 364     {
 365       /* Determine the next slot to use in the cache.  */
 366       if (insert_at_next_slot_p)
 367         ix = cache->next_slot++;
 368       else
 369         ix = *ix_p;
 370
 371       entry = (struct tree_int_map *)pool_alloc (cache->node_map_entries);
 372       entry->base.from = t;
 373       entry->to = (unsigned) ix;
 374       *slot = entry;
 375
 376       /* If no offset was given, store the invalid offset -1.  */
 377       offset = (offset_p) ? *offset_p : (unsigned) -1;
 378
 379       lto_streamer_cache_add_to_node_array (cache, ix, t, offset);
 380
 381       /* Indicate that the item was not present in the cache.  */
 382       existed_p = false;
 383     }
 384   else
 385     {
 386       entry = (struct tree_int_map *) *slot;
 387       ix = (int) entry->to;
 388       offset = VEC_index (unsigned, cache->offsets, ix);
 389
 390       if (!insert_at_next_slot_p && ix != *ix_p)
 391         {
 392           /* If the caller wants to insert T at a specific slot
 393              location, and ENTRY->TO does not match *IX_P, add T to
 394              the requested location slot.  This situation arises when
 395              streaming builtin functions.
 396
 397              For instance, on the writer side we could have two
 398              FUNCTION_DECLS T1 and T2 that are represented by the same
 399              builtin function.  The reader will only instantiate the
 400              canonical builtin, but since T1 and T2 had been
 401              originally stored in different cache slots (S1 and S2),
 402              the reader must be able to find the canonical builtin
 403              function at slots S1 and S2.  */
 404           gcc_assert (lto_stream_as_builtin_p (t));
 405           ix = *ix_p;
 406
 407           /* Since we are storing a builtin, the offset into the
 408              stream is not necessary as we will not need to read
 409              forward in the stream.  */
 410           lto_streamer_cache_add_to_node_array (cache, ix, t, -1);
 411         }
 412
 413       /* Indicate that T was already in the cache.  */
 414       existed_p = true;
 415     }
 416
 417   if (ix_p)
 418     *ix_p = ix;
 419
 420   if (offset_p)
 421     *offset_p = offset;
 422
 423   return existed_p;
 424 }
 425
 426
 427 /* Insert tree node T in CACHE.  If T already existed in the cache
 428    return true.  Otherwise, return false.
 429
 430    If IX_P is non-null, update it with the index into the cache where
 431    T has been stored.
 432
 433    *OFFSET_P represents the offset in the stream where T is physically
 434    written out.  The first time T is added to the cache, *OFFSET_P is
 435    recorded in the cache together with T.  But if T already existed
 436    in the cache, *OFFSET_P is updated with the value that was recorded
 437    the first time T was added to the cache.
 438
 439    If OFFSET_P is NULL, it is ignored.  */
 440
 441 bool
 442 lto_streamer_cache_insert (struct lto_streamer_cache_d *cache, tree t,
 443                            int *ix_p, unsigned *offset_p)
 444 {
 445   return lto_streamer_cache_insert_1 (cache, t, ix_p, offset_p, true);
 446 }
 447
 448
 449 /* Insert tree node T in CACHE at slot IX.  If T already
 450    existed in the cache return true.  Otherwise, return false.  */
 451
 452 bool
 453 lto_streamer_cache_insert_at (struct lto_streamer_cache_d *cache,
 454                               tree t, int ix)
 455 {
 456   return lto_streamer_cache_insert_1 (cache, t, &ix, NULL, false);
 457 }
 458
 459
 460 /* Return true if tree node T exists in CACHE.  If IX_P is
 461    not NULL, write to *IX_P the index into the cache where T is stored
 462    (-1 if T is not found).  */
 463
 464 bool
 465 lto_streamer_cache_lookup (struct lto_streamer_cache_d *cache, tree t,
 466                            int *ix_p)
 467 {
 468   void **slot;
 469   struct tree_int_map d_slot;
 470   bool retval;
 471   int ix;
 472
 473   gcc_assert (t);
 474
 475   d_slot.base.from = t;
 476   slot = htab_find_slot (cache->node_map, &d_slot, NO_INSERT);
 477   if (slot == NULL)
 478     {
 479       retval = false;
 480       ix = -1;
 481     }
 482   else
 483     {
 484       retval = true;
 485       ix = (int) ((struct tree_int_map *) *slot)->to;
 486     }
 487
 488   if (ix_p)
 489     *ix_p = ix;
 490
 491   return retval;
 492 }
 493
 494
 495 /* Return the tree node at slot IX in CACHE.  */
 496
 497 tree
 498 lto_streamer_cache_get (struct lto_streamer_cache_d *cache, int ix)
 499 {
 500   gcc_assert (cache);
 501
 502   /* If the reader is requesting an index beyond the length of the
 503      cache, it will need to read ahead.  Return NULL_TREE to indicate
 504      that.  */
 505   if ((unsigned) ix >= VEC_length (tree, cache->nodes))
 506     return NULL_TREE;
 507
 508   return VEC_index (tree, cache->nodes, (unsigned) ix);
 509 }
 510
 511
 512 /* Record NODE in COMMON_NODES if it is not NULL and is not already in
 513    SEEN_NODES.  */
 514
 515 static void
 516 lto_record_common_node (tree *nodep, VEC(tree, heap) **common_nodes,
 517                         struct pointer_set_t *seen_nodes)
 518 {
 519   tree node = *nodep;
 520
 521   if (node == NULL_TREE)
 522     return;
 523
 524   if (TYPE_P (node))
 525     {
 526       /* Type merging will get confused by the canonical types as they
 527          are set by the middle-end.  */
 528       if (in_lto_p)
 529         TYPE_CANONICAL (node) = NULL_TREE;
 530       *nodep = node = gimple_register_type (node);
 531     }
 532
 533   /* Return if node is already seen.  */
 534   if (pointer_set_insert (seen_nodes, node))
 535     return;
 536
 537   VEC_safe_push (tree, heap, *common_nodes, node);
 538
 539   if (tree_node_can_be_shared (node))
 540     {
 541       if (POINTER_TYPE_P (node)
 542           || TREE_CODE (node) == COMPLEX_TYPE
 543           || TREE_CODE (node) == ARRAY_TYPE)
 544         lto_record_common_node (&TREE_TYPE (node), common_nodes, seen_nodes);
 545     }
 546 }
 547
 548
 549 /* Generate a vector of common nodes and make sure they are merged
 550    properly according to the the gimple type table.  */
 551
 552 static VEC(tree,heap) *
 553 lto_get_common_nodes (void)
 554 {
 555   unsigned i;
 556   VEC(tree,heap) *common_nodes = NULL;
 557   struct pointer_set_t *seen_nodes;
 558
 559   /* The MAIN_IDENTIFIER_NODE is normally set up by the front-end, but the
 560      LTO back-end must agree. Currently, the only languages that set this
 561      use the name "main".  */
 562   if (main_identifier_node)
 563     {
 564       const char *main_name = IDENTIFIER_POINTER (main_identifier_node);
 565       gcc_assert (strcmp (main_name, "main") == 0);
 566     }
 567   else
 568     main_identifier_node = get_identifier ("main");
 569
 570   gcc_assert (ptrdiff_type_node == integer_type_node);
 571
 572   /* FIXME lto.  In the C++ front-end, fileptr_type_node is defined as a
 573      variant copy of of ptr_type_node, rather than ptr_node itself.  The
 574      distinction should only be relevant to the front-end, so we always
 575      use the C definition here in lto1.
 576
 577      These should be assured in pass_ipa_free_lang_data.  */
 578   gcc_assert (fileptr_type_node == ptr_type_node);
 579   gcc_assert (TYPE_MAIN_VARIANT (fileptr_type_node) == ptr_type_node);
 580
 581   seen_nodes = pointer_set_create ();
 582
 583   /* Skip itk_char.  char_type_node is shared with the appropriately
 584      signed variant.  */
 585   for (i = itk_signed_char; i < itk_none; i++)
 586     lto_record_common_node (&integer_types[i], &common_nodes, seen_nodes);
 587
 588   for (i = 0; i < TYPE_KIND_LAST; i++)
 589     lto_record_common_node (&sizetype_tab[i], &common_nodes, seen_nodes);
 590
 591   for (i = 0; i < TI_MAX; i++)
 592     lto_record_common_node (&global_trees[i], &common_nodes, seen_nodes);
 593
 594   pointer_set_destroy (seen_nodes);
 595
 596   return common_nodes;
 597 }
 598
 599
 600 /* Assign an index to tree node T and enter it in the streamer cache
 601    CACHE.  */
 602
 603 static void
 604 preload_common_node (struct lto_streamer_cache_d *cache, tree t)
 605 {
 606   gcc_assert (t);
 607
 608   lto_streamer_cache_insert (cache, t, NULL, NULL);
 609
 610  /* The FIELD_DECLs of structures should be shared, so that every
 611     COMPONENT_REF uses the same tree node when referencing a field.
 612     Pointer equality between FIELD_DECLs is used by the alias
 613     machinery to compute overlapping memory references (See
 614     nonoverlapping_component_refs_p).  */
 615  if (TREE_CODE (t) == RECORD_TYPE)
 616    {
 617      tree f;
 618
 619      for (f = TYPE_FIELDS (t); f; f = TREE_CHAIN (f))
 620        preload_common_node (cache, f);
 621    }
 622 }
 623
 624
 625 /* Create a cache of pickled nodes.  */
 626
 627 struct lto_streamer_cache_d *
 628 lto_streamer_cache_create (void)
 629 {
 630   struct lto_streamer_cache_d *cache;
 631   VEC(tree, heap) *common_nodes;
 632   unsigned i;
 633   tree node;
 634
 635   cache = XCNEW (struct lto_streamer_cache_d);
 636
 637   cache->node_map = htab_create (101, tree_int_map_hash, tree_int_map_eq, NULL);
 638
 639   cache->node_map_entries = create_alloc_pool ("node map",
 640                                                sizeof (struct tree_int_map),
 641                                                100);
 642
 643   /* Load all the well-known tree nodes that are always created by
 644      the compiler on startup.  This prevents writing them out
 645      unnecessarily.  */
 646   common_nodes = lto_get_common_nodes ();
 647
 648   FOR_EACH_VEC_ELT (tree, common_nodes, i, node)
 649     preload_common_node (cache, node);
 650
 651   VEC_free(tree, heap, common_nodes);
 652
 653   return cache;
 654 }
 655
 656
 657 /* Delete the streamer cache C.  */
 658
 659 void
 660 lto_streamer_cache_delete (struct lto_streamer_cache_d *c)
 661 {
 662   if (c == NULL)
 663     return;
 664
 665   htab_delete (c->node_map);
 666   free_alloc_pool (c->node_map_entries);
 667   VEC_free (tree, heap, c->nodes);
 668   VEC_free (unsigned, heap, c->offsets);
 669   free (c);
 670 }
 671
 672
 673 #ifdef LTO_STREAMER_DEBUG
 674 static htab_t tree_htab;
 675
 676 struct tree_hash_entry
 677 {
 678   tree key;
 679   intptr_t value;
 680 };
 681
 682 static hashval_t
 683 hash_tree (const void *p)
 684 {
 685   const struct tree_hash_entry *e = (const struct tree_hash_entry *) p;
 686   return htab_hash_pointer (e->key);
 687 }
 688
 689 static int
 690 eq_tree (const void *p1, const void *p2)
 691 {
 692   const struct tree_hash_entry *e1 = (const struct tree_hash_entry *) p1;
 693   const struct tree_hash_entry *e2 = (const struct tree_hash_entry *) p2;
 694   return (e1->key == e2->key);
 695 }
 696 #endif
 697
 698 /* Initialization common to the LTO reader and writer.  */
 699
 700 void
 701 lto_streamer_init (void)
 702 {
 703   /* Check that all the TS_* handled by the reader and writer routines
 704      match exactly the structures defined in treestruct.def.  When a
 705      new TS_* astructure is added, the streamer should be updated to
 706      handle it.  */
 707   check_handled_ts_structures ();
 708
 709 #ifdef LTO_STREAMER_DEBUG
 710   tree_htab = htab_create (31, hash_tree, eq_tree, NULL);
 711 #endif
 712 }
 713
 714
 715 /* Gate function for all LTO streaming passes.  */
 716
 717 bool
 718 gate_lto_out (void)
 719 {
 720   return ((flag_generate_lto || in_lto_p)
 721           /* Don't bother doing anything if the program has errors.  */
 722           && !seen_error ());
 723 }
 724
 725
 726 #ifdef LTO_STREAMER_DEBUG
 727 /* Add a mapping between T and ORIG_T, which is the numeric value of
 728    the original address of T as it was seen by the LTO writer.  This
 729    mapping is useful when debugging streaming problems.  A debugging
 730    session can be started on both reader and writer using ORIG_T
 731    as a breakpoint value in both sessions.
 732
 733    Note that this mapping is transient and only valid while T is
 734    being reconstructed.  Once T is fully built, the mapping is
 735    removed.  */
 736
 737 void
 738 lto_orig_address_map (tree t, intptr_t orig_t)
 739 {
 740   struct tree_hash_entry ent;
 741   struct tree_hash_entry **slot;
 742
 743   ent.key = t;
 744   ent.value = orig_t;
 745   slot
 746     = (struct tree_hash_entry **) htab_find_slot (tree_htab, &ent, INSERT);
 747   gcc_assert (!*slot);
 748   *slot = XNEW (struct tree_hash_entry);
 749   **slot = ent;
 750 }
 751
 752
 753 /* Get the original address of T as it was seen by the writer.  This
 754    is only valid while T is being reconstructed.  */
 755
 756 intptr_t
 757 lto_orig_address_get (tree t)
 758 {
 759   struct tree_hash_entry ent;
 760   struct tree_hash_entry **slot;
 761
 762   ent.key = t;
 763   slot
 764     = (struct tree_hash_entry **) htab_find_slot (tree_htab, &ent, NO_INSERT);
 765   return (slot ? (*slot)->value : 0);
 766 }
 767
 768
 769 /* Clear the mapping of T to its original address.  */
 770
 771 void
 772 lto_orig_address_remove (tree t)
 773 {
 774   struct tree_hash_entry ent;
 775   struct tree_hash_entry **slot;
 776
 777   ent.key = t;
 778   slot
 779     = (struct tree_hash_entry **) htab_find_slot (tree_htab, &ent, NO_INSERT);
 780   gcc_assert (slot);
 781   free (*slot);
 782   htab_clear_slot (tree_htab, (PTR *)slot);
 783 }
 784 #endif
 785
 786
 787 /* Check that the version MAJOR.MINOR is the correct version number.  */
 788
 789 void
 790 lto_check_version (int major, int minor)
 791 {
 792   if (major != LTO_major_version || minor != LTO_minor_version)
 793     fatal_error ("bytecode stream generated with LTO version %d.%d instead "
 794                  "of the expected %d.%d",
 795                  major, minor,
 796                  LTO_major_version, LTO_minor_version);
 797 }