gcc/varpool.c

   1 /* Callgraph handling code.
   2    Copyright (C) 2003-2015 Free Software Foundation, Inc.
   3    Contributed by Jan Hubicka
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 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 "hash-set.h"
  26 #include "machmode.h"
  27 #include "vec.h"
  28 #include "double-int.h"
  29 #include "input.h"
  30 #include "alias.h"
  31 #include "symtab.h"
  32 #include "wide-int.h"
  33 #include "inchash.h"
  34 #include "tree.h"
  35 #include "fold-const.h"
  36 #include "varasm.h"
  37 #include "predict.h"
  38 #include "basic-block.h"
  39 #include "hash-map.h"
  40 #include "is-a.h"
  41 #include "plugin-api.h"
  42 #include "hard-reg-set.h"
  43 #include "input.h"
  44 #include "function.h"
  45 #include "ipa-ref.h"
  46 #include "cgraph.h"
  47 #include "langhooks.h"
  48 #include "diagnostic-core.h"
  49 #include "timevar.h"
  50 #include "debug.h"
  51 #include "target.h"
  52 #include "output.h"
  53 #include "gimple-expr.h"
  54 #include "flags.h"
  55 #include "tree-ssa-alias.h"
  56 #include "gimple.h"
  57 #include "lto-streamer.h"
  58 #include "context.h"
  59 #include "omp-low.h"
  60
  61 const char * const tls_model_names[]={"none", "emulated",
  62                                       "global-dynamic", "local-dynamic",
  63                                       "initial-exec", "local-exec"};
  64
  65 /* List of hooks triggered on varpool_node events.  */
  66 struct varpool_node_hook_list {
  67   varpool_node_hook hook;
  68   void *data;
  69   struct varpool_node_hook_list *next;
  70 };
  71
  72 /* Register HOOK to be called with DATA on each removed node.  */
  73 varpool_node_hook_list *
  74 symbol_table::add_varpool_removal_hook (varpool_node_hook hook, void *data)
  75 {
  76   varpool_node_hook_list *entry;
  77   varpool_node_hook_list **ptr = &m_first_varpool_removal_hook;
  78
  79   entry = (varpool_node_hook_list *) xmalloc (sizeof (*entry));
  80   entry->hook = hook;
  81   entry->data = data;
  82   entry->next = NULL;
  83   while (*ptr)
  84     ptr = &(*ptr)->next;
  85   *ptr = entry;
  86   return entry;
  87 }
  88
  89 /* Remove ENTRY from the list of hooks called on removing nodes.  */
  90 void
  91 symbol_table::remove_varpool_removal_hook (varpool_node_hook_list *entry)
  92 {
  93   varpool_node_hook_list **ptr = &m_first_varpool_removal_hook;
  94
  95   while (*ptr != entry)
  96     ptr = &(*ptr)->next;
  97   *ptr = entry->next;
  98   free (entry);
  99 }
 100
 101 /* Call all node removal hooks.  */
 102 void
 103 symbol_table::call_varpool_removal_hooks (varpool_node *node)
 104 {
 105   varpool_node_hook_list *entry = m_first_varpool_removal_hook;
 106   while (entry)
 107   {
 108     entry->hook (node, entry->data);
 109     entry = entry->next;
 110   }
 111 }
 112
 113 /* Register HOOK to be called with DATA on each inserted node.  */
 114 varpool_node_hook_list *
 115 symbol_table::add_varpool_insertion_hook (varpool_node_hook hook, void *data)
 116 {
 117   varpool_node_hook_list *entry;
 118   varpool_node_hook_list **ptr = &m_first_varpool_insertion_hook;
 119
 120   entry = (varpool_node_hook_list *) xmalloc (sizeof (*entry));
 121   entry->hook = hook;
 122   entry->data = data;
 123   entry->next = NULL;
 124   while (*ptr)
 125     ptr = &(*ptr)->next;
 126   *ptr = entry;
 127   return entry;
 128 }
 129
 130 /* Remove ENTRY from the list of hooks called on inserted nodes.  */
 131 void
 132 symbol_table::remove_varpool_insertion_hook (varpool_node_hook_list *entry)
 133 {
 134   varpool_node_hook_list **ptr = &m_first_varpool_insertion_hook;
 135
 136   while (*ptr != entry)
 137     ptr = &(*ptr)->next;
 138   *ptr = entry->next;
 139   free (entry);
 140 }
 141
 142 /* Call all node insertion hooks.  */
 143 void
 144 symbol_table::call_varpool_insertion_hooks (varpool_node *node)
 145 {
 146   varpool_node_hook_list *entry = m_first_varpool_insertion_hook;
 147   while (entry)
 148   {
 149     entry->hook (node, entry->data);
 150     entry = entry->next;
 151   }
 152 }
 153
 154 /* Allocate new callgraph node and insert it into basic data structures.  */
 155
 156 varpool_node *
 157 varpool_node::create_empty (void)
 158 {
 159   varpool_node *node = ggc_cleared_alloc<varpool_node> ();
 160   node->type = SYMTAB_VARIABLE;
 161   return node;
 162 }
 163
 164 /* Return varpool node assigned to DECL.  Create new one when needed.  */
 165 varpool_node *
 166 varpool_node::get_create (tree decl)
 167 {
 168   varpool_node *node = varpool_node::get (decl);
 169   gcc_checking_assert (TREE_CODE (decl) == VAR_DECL);
 170   if (node)
 171     return node;
 172
 173   node = varpool_node::create_empty ();
 174   node->decl = decl;
 175
 176   if ((flag_openacc || flag_openmp)
 177       && lookup_attribute ("omp declare target", DECL_ATTRIBUTES (decl)))
 178     {
 179       node->offloadable = 1;
 180 #ifdef ENABLE_OFFLOADING
 181       g->have_offload = true;
 182       if (!in_lto_p)
 183         vec_safe_push (offload_vars, decl);
 184       node->force_output = 1;
 185 #endif
 186     }
 187
 188   node->register_symbol ();
 189   return node;
 190 }
 191
 192 /* Remove variable from symbol table.  */
 193
 194 void
 195 varpool_node::remove (void)
 196 {
 197   symtab->call_varpool_removal_hooks (this);
 198
 199   /* When streaming we can have multiple nodes associated with decl.  */
 200   if (symtab->state == LTO_STREAMING)
 201     ;
 202   /* Keep constructor when it may be used for folding. We remove
 203      references to external variables before final compilation.  */
 204   else if (DECL_INITIAL (decl) && DECL_INITIAL (decl) != error_mark_node
 205            && !ctor_useable_for_folding_p ())
 206     remove_initializer ();
 207
 208   unregister ();
 209   ggc_free (this);
 210 }
 211
 212 /* Remove node initializer when it is no longer needed.  */
 213 void
 214 varpool_node::remove_initializer (void)
 215 {
 216   if (DECL_INITIAL (decl)
 217       && !DECL_IN_CONSTANT_POOL (decl)
 218       /* Keep vtables for BINFO folding.  */
 219       && !DECL_VIRTUAL_P (decl)
 220       /* FIXME: http://gcc.gnu.org/PR55395 */
 221       && debug_info_level == DINFO_LEVEL_NONE
 222       /* When doing declaration merging we have duplicate
 223          entries for given decl.  Do not attempt to remove
 224          the boides, or we will end up remiving
 225          wrong one.  */
 226       && symtab->state != LTO_STREAMING)
 227     DECL_INITIAL (decl) = error_mark_node;
 228 }
 229
 230 /* Dump given varpool node to F.  */
 231 void
 232 varpool_node::dump (FILE *f)
 233 {
 234   dump_base (f);
 235   fprintf (f, "  Availability: %s\n",
 236            symtab->function_flags_ready
 237            ? cgraph_availability_names[get_availability ()]
 238            : "not-ready");
 239   fprintf (f, "  Varpool flags:");
 240   if (DECL_INITIAL (decl))
 241     fprintf (f, " initialized");
 242   if (output)
 243     fprintf (f, " output");
 244   if (used_by_single_function)
 245     fprintf (f, " used-by-single-function");
 246   if (need_bounds_init)
 247     fprintf (f, " need-bounds-init");
 248   if (TREE_READONLY (decl))
 249     fprintf (f, " read-only");
 250   if (ctor_useable_for_folding_p ())
 251     fprintf (f, " const-value-known");
 252   if (writeonly)
 253     fprintf (f, " write-only");
 254   if (tls_model)
 255     fprintf (f, " tls-%s", tls_model_names [tls_model]);
 256   fprintf (f, "\n");
 257 }
 258
 259
 260 /* Dump given varpool node to stderr.  */
 261 void varpool_node::debug (void)
 262 {
 263   varpool_node::dump (stderr);
 264 }
 265
 266 /* Dump the variable pool to F.  */
 267 void
 268 varpool_node::dump_varpool (FILE *f)
 269 {
 270   varpool_node *node;
 271
 272   fprintf (f, "variable pool:\n\n");
 273   FOR_EACH_VARIABLE (node)
 274     node->dump (f);
 275 }
 276
 277 /* Dump the variable pool to stderr.  */
 278
 279 DEBUG_FUNCTION void
 280 varpool_node::debug_varpool (void)
 281 {
 282   dump_varpool (stderr);
 283 }
 284
 285 /* Given an assembler name, lookup node.  */
 286 varpool_node *
 287 varpool_node::get_for_asmname (tree asmname)
 288 {
 289   if (symtab_node *node = symtab_node::get_for_asmname (asmname))
 290     return dyn_cast <varpool_node *> (node);
 291   else
 292     return NULL;
 293 }
 294
 295 /* When doing LTO, read variable's constructor from disk if
 296    it is not already present.  */
 297
 298 tree
 299 varpool_node::get_constructor (void)
 300 {
 301   lto_file_decl_data *file_data;
 302   const char *data, *name;
 303   size_t len;
 304
 305   if (DECL_INITIAL (decl) != error_mark_node
 306       || !in_lto_p
 307       || !lto_file_data)
 308     return DECL_INITIAL (decl);
 309
 310   timevar_push (TV_IPA_LTO_CTORS_IN);
 311
 312   file_data = lto_file_data;
 313   name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
 314
 315   /* We may have renamed the declaration, e.g., a static function.  */
 316   name = lto_get_decl_name_mapping (file_data, name);
 317
 318   data = lto_get_section_data (file_data, LTO_section_function_body,
 319                                name, &len);
 320   if (!data)
 321     fatal_error (input_location, "%s: section %s is missing",
 322                  file_data->file_name,
 323                  name);
 324
 325   lto_input_variable_constructor (file_data, this, data);
 326   lto_stats.num_function_bodies++;
 327   lto_free_section_data (file_data, LTO_section_function_body, name,
 328                          data, len);
 329   lto_free_function_in_decl_state_for_node (this);
 330   timevar_pop (TV_IPA_LTO_CTORS_IN);
 331   return DECL_INITIAL (decl);
 332 }
 333
 334 /* Return true if variable has constructor that can be used for folding.  */
 335
 336 bool
 337 varpool_node::ctor_useable_for_folding_p (void)
 338 {
 339   varpool_node *real_node = this;
 340
 341   if (real_node->alias && real_node->definition)
 342     real_node = ultimate_alias_target ();
 343
 344   if (TREE_CODE (decl) == CONST_DECL
 345       || DECL_IN_CONSTANT_POOL (decl))
 346     return true;
 347   if (TREE_THIS_VOLATILE (decl))
 348     return false;
 349
 350   /* If we do not have a constructor, we can't use it.  */
 351   if (DECL_INITIAL (real_node->decl) == error_mark_node
 352       && !real_node->lto_file_data)
 353     return false;
 354
 355   /* Avoid attempts to load constructors that was not streamed.  */
 356   if (flag_ltrans && DECL_INITIAL (real_node->decl) == error_mark_node
 357       && real_node->body_removed)
 358     return false;
 359
 360   /* Vtables are defined by their types and must match no matter of interposition
 361      rules.  */
 362   if (DECL_VIRTUAL_P (decl))
 363     {
 364       /* The C++ front end creates VAR_DECLs for vtables of typeinfo
 365          classes not defined in the current TU so that it can refer
 366          to them from typeinfo objects.  Avoid returning NULL_TREE.  */
 367       return DECL_INITIAL (real_node->decl) != NULL;
 368     }
 369
 370   /* Alias of readonly variable is also readonly, since the variable is stored
 371      in readonly memory.  We also accept readonly aliases of non-readonly
 372      locations assuming that user knows what he is asking for.  */
 373   if (!TREE_READONLY (decl) && !TREE_READONLY (real_node->decl))
 374     return false;
 375
 376   /* Variables declared 'const' without an initializer
 377      have zero as the initializer if they may not be
 378      overridden at link or run time.
 379
 380      It is actually requirement for C++ compiler to optimize const variables
 381      consistently. As a GNU extension, do not enfore this rule for user defined
 382      weak variables, so we support interposition on:
 383      static const int dummy = 0;
 384      extern const int foo __attribute__((__weak__, __alias__("dummy")));
 385    */
 386   if ((!DECL_INITIAL (real_node->decl)
 387        || (DECL_WEAK (decl) && !DECL_COMDAT (decl)))
 388       && (DECL_EXTERNAL (decl) || decl_replaceable_p (decl)))
 389     return false;
 390
 391   /* Variables declared `const' with an initializer are considered
 392      to not be overwritable with different initializer by default.
 393
 394      ??? Previously we behaved so for scalar variables but not for array
 395      accesses.  */
 396   return true;
 397 }
 398
 399 /* If DECLARATION is constant variable and its initial value is known
 400    (so we can do constant folding), return its constructor (DECL_INITIAL).
 401    This may be an expression or NULL when DECL is initialized to 0.
 402    Return ERROR_MARK_NODE otherwise.
 403
 404    In LTO this may actually trigger reading the constructor from disk.
 405    For this reason varpool_ctor_useable_for_folding_p should be used when
 406    the actual constructor value is not needed.  */
 407
 408 tree
 409 ctor_for_folding (tree decl)
 410 {
 411   varpool_node *node, *real_node;
 412   tree real_decl;
 413
 414   if (TREE_CODE (decl) != VAR_DECL
 415       && TREE_CODE (decl) != CONST_DECL)
 416     return error_mark_node;
 417
 418   /* Static constant bounds are created to be
 419      used instead of constants and therefore
 420      do not let folding it.  */
 421   if (POINTER_BOUNDS_P (decl))
 422     return error_mark_node;
 423
 424   if (TREE_CODE (decl) == CONST_DECL
 425       || DECL_IN_CONSTANT_POOL (decl))
 426     return DECL_INITIAL (decl);
 427
 428   if (TREE_THIS_VOLATILE (decl))
 429     return error_mark_node;
 430
 431   /* Do not care about automatic variables.  Those are never initialized
 432      anyway, because gimplifier exapnds the code.  */
 433   if (!TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
 434     {
 435       gcc_assert (!TREE_PUBLIC (decl));
 436       return error_mark_node;
 437     }
 438
 439   gcc_assert (TREE_CODE (decl) == VAR_DECL);
 440
 441   real_node = node = varpool_node::get (decl);
 442   if (node)
 443     {
 444       real_node = node->ultimate_alias_target ();
 445       real_decl = real_node->decl;
 446     }
 447   else
 448     real_decl = decl;
 449
 450   /* See if we are dealing with alias.
 451      In most cases alias is just alternative symbol pointing to a given
 452      constructor.  This allows us to use interposition rules of DECL
 453      constructor of REAL_NODE.  However weakrefs are special by being just
 454      alternative name of their target (if defined).  */
 455   if (decl != real_decl)
 456     {
 457       gcc_assert (!DECL_INITIAL (decl)
 458                   || (node->alias && node->get_alias_target () == real_node)
 459                   || DECL_INITIAL (decl) == error_mark_node);
 460       if (node->weakref)
 461         {
 462           node = node->get_alias_target ();
 463           decl = node->decl;
 464         }
 465     }
 466
 467   if ((!DECL_VIRTUAL_P (real_decl)
 468        || DECL_INITIAL (real_decl) == error_mark_node
 469        || !DECL_INITIAL (real_decl))
 470       && (!node || !node->ctor_useable_for_folding_p ()))
 471     return error_mark_node;
 472
 473   /* OK, we can return constructor.  See if we need to fetch it from disk
 474      in LTO mode.  */
 475   if (DECL_INITIAL (real_decl) != error_mark_node
 476       || !in_lto_p)
 477     return DECL_INITIAL (real_decl);
 478   return real_node->get_constructor ();
 479 }
 480
 481 /* Add the variable DECL to the varpool.
 482    Unlike finalize_decl function is intended to be used
 483    by middle end and allows insertion of new variable at arbitrary point
 484    of compilation.  */
 485 void
 486 varpool_node::add (tree decl)
 487 {
 488   varpool_node *node;
 489   varpool_node::finalize_decl (decl);
 490   node = varpool_node::get_create (decl);
 491   symtab->call_varpool_insertion_hooks (node);
 492   if (node->externally_visible_p ())
 493     node->externally_visible = true;
 494   if (lookup_attribute ("no_reorder", DECL_ATTRIBUTES (decl)))
 495     node->no_reorder = 1;
 496 }
 497
 498 /* Return variable availability.  See cgraph.h for description of individual
 499    return values.  */
 500 enum availability
 501 varpool_node::get_availability (void)
 502 {
 503   if (!definition)
 504     return AVAIL_NOT_AVAILABLE;
 505   if (!TREE_PUBLIC (decl))
 506     return AVAIL_AVAILABLE;
 507   if (DECL_IN_CONSTANT_POOL (decl)
 508       || DECL_VIRTUAL_P (decl))
 509     return AVAIL_AVAILABLE;
 510   if (alias && weakref)
 511     {
 512       enum availability avail;
 513
 514       ultimate_alias_target (&avail)->get_availability ();
 515       return avail;
 516     }
 517   /* If the variable can be overwritten, return OVERWRITABLE.  Takes
 518      care of at least one notable extension - the COMDAT variables
 519      used to share template instantiations in C++.  */
 520   if (decl_replaceable_p (decl)
 521       || DECL_EXTERNAL (decl))
 522     return AVAIL_INTERPOSABLE;
 523   return AVAIL_AVAILABLE;
 524 }
 525
 526 void
 527 varpool_node::analyze (void)
 528 {
 529   /* When reading back varpool at LTO time, we re-construct the queue in order
 530      to have "needed" list right by inserting all needed nodes into varpool.
 531      We however don't want to re-analyze already analyzed nodes.  */
 532   if (!analyzed)
 533     {
 534       gcc_assert (!in_lto_p || symtab->function_flags_ready);
 535       /* Compute the alignment early so function body expanders are
 536          already informed about increased alignment.  */
 537       align_variable (decl, 0);
 538     }
 539   if (alias)
 540     resolve_alias (varpool_node::get (alias_target));
 541   else if (DECL_INITIAL (decl))
 542     record_references_in_initializer (decl, analyzed);
 543   analyzed = true;
 544 }
 545
 546 /* Assemble thunks and aliases associated to varpool node.  */
 547
 548 void
 549 varpool_node::assemble_aliases (void)
 550 {
 551   ipa_ref *ref;
 552
 553   FOR_EACH_ALIAS (this, ref)
 554     {
 555       varpool_node *alias = dyn_cast <varpool_node *> (ref->referring);
 556       do_assemble_alias (alias->decl,
 557                          DECL_ASSEMBLER_NAME (decl));
 558       alias->assemble_aliases ();
 559     }
 560 }
 561
 562 /* Output one variable, if necessary.  Return whether we output it.  */
 563
 564 bool
 565 varpool_node::assemble_decl (void)
 566 {
 567   /* Aliases are outout when their target is produced or by
 568      output_weakrefs.  */
 569   if (alias)
 570     return false;
 571
 572   /* Constant pool is output from RTL land when the reference
 573      survive till this level.  */
 574   if (DECL_IN_CONSTANT_POOL (decl) && TREE_ASM_WRITTEN (decl))
 575     return false;
 576
 577   /* Decls with VALUE_EXPR should not be in the varpool at all.  They
 578      are not real variables, but just info for debugging and codegen.
 579      Unfortunately at the moment emutls is not updating varpool correctly
 580      after turning real vars into value_expr vars.  */
 581   if (DECL_HAS_VALUE_EXPR_P (decl)
 582       && !targetm.have_tls)
 583     return false;
 584
 585   /* Hard register vars do not need to be output.  */
 586   if (DECL_HARD_REGISTER (decl))
 587     return false;
 588
 589   gcc_checking_assert (!TREE_ASM_WRITTEN (decl)
 590                        && TREE_CODE (decl) == VAR_DECL
 591                        && !DECL_HAS_VALUE_EXPR_P (decl));
 592
 593   if (!in_other_partition
 594       && !DECL_EXTERNAL (decl))
 595     {
 596       get_constructor ();
 597       assemble_variable (decl, 0, 1, 0);
 598       gcc_assert (TREE_ASM_WRITTEN (decl));
 599       gcc_assert (definition);
 600       assemble_aliases ();
 601       return true;
 602     }
 603
 604   return false;
 605 }
 606
 607 /* Add NODE to queue starting at FIRST.
 608    The queue is linked via AUX pointers and terminated by pointer to 1.  */
 609
 610 static void
 611 enqueue_node (varpool_node *node, varpool_node **first)
 612 {
 613   if (node->aux)
 614     return;
 615   gcc_checking_assert (*first);
 616   node->aux = *first;
 617   *first = node;
 618 }
 619
 620 /* Optimization of function bodies might've rendered some variables as
 621    unnecessary so we want to avoid these from being compiled.  Re-do
 622    reachability starting from variables that are either externally visible
 623    or was referred from the asm output routines.  */
 624
 625 void
 626 symbol_table::remove_unreferenced_decls (void)
 627 {
 628   varpool_node *next, *node;
 629   varpool_node *first = (varpool_node *)(void *)1;
 630   int i;
 631   ipa_ref *ref = NULL;
 632   hash_set<varpool_node *> referenced;
 633
 634   if (seen_error ())
 635     return;
 636
 637   if (dump_file)
 638     fprintf (dump_file, "Trivially needed variables:");
 639   FOR_EACH_DEFINED_VARIABLE (node)
 640     {
 641       if (node->analyzed
 642           && (!node->can_remove_if_no_refs_p ()
 643               /* We just expanded all function bodies.  See if any of
 644                  them needed the variable.  */
 645               || DECL_RTL_SET_P (node->decl)))
 646         {
 647           enqueue_node (node, &first);
 648           if (dump_file)
 649             fprintf (dump_file, " %s", node->asm_name ());
 650         }
 651     }
 652   while (first != (varpool_node *)(void *)1)
 653     {
 654       node = first;
 655       first = (varpool_node *)first->aux;
 656
 657       if (node->same_comdat_group)
 658         {
 659           symtab_node *next;
 660           for (next = node->same_comdat_group;
 661                next != node;
 662                next = next->same_comdat_group)
 663             {
 664               varpool_node *vnext = dyn_cast <varpool_node *> (next);
 665               if (vnext && vnext->analyzed && !next->comdat_local_p ())
 666                 enqueue_node (vnext, &first);
 667             }
 668         }
 669       for (i = 0; node->iterate_reference (i, ref); i++)
 670         {
 671           varpool_node *vnode = dyn_cast <varpool_node *> (ref->referred);
 672           if (vnode
 673               && !vnode->in_other_partition
 674               && (!DECL_EXTERNAL (ref->referred->decl)
 675                   || vnode->alias)
 676               && vnode->analyzed)
 677             enqueue_node (vnode, &first);
 678           else
 679             referenced.add (node);
 680         }
 681     }
 682   if (dump_file)
 683     fprintf (dump_file, "\nRemoving variables:");
 684   for (node = first_defined_variable (); node; node = next)
 685     {
 686       next = next_defined_variable (node);
 687       if (!node->aux && !node->no_reorder)
 688         {
 689           if (dump_file)
 690             fprintf (dump_file, " %s", node->asm_name ());
 691           if (referenced.contains(node))
 692             node->remove_initializer ();
 693           else
 694             node->remove ();
 695         }
 696     }
 697
 698   if (dump_file)
 699     fprintf (dump_file, "\n");
 700 }
 701
 702 /* For variables in named sections make sure get_variable_section
 703    is called before we switch to those sections.  Then section
 704    conflicts between read-only and read-only requiring relocations
 705    sections can be resolved.  */
 706 void
 707 varpool_node::finalize_named_section_flags (void)
 708 {
 709   if (!TREE_ASM_WRITTEN (decl)
 710       && !alias
 711       && !in_other_partition
 712       && !DECL_EXTERNAL (decl)
 713       && TREE_CODE (decl) == VAR_DECL
 714       && !DECL_HAS_VALUE_EXPR_P (decl)
 715       && get_section ())
 716     get_variable_section (decl, false);
 717 }
 718
 719 /* Output all variables enqueued to be assembled.  */
 720 bool
 721 symbol_table::output_variables (void)
 722 {
 723   bool changed = false;
 724   varpool_node *node;
 725
 726   if (seen_error ())
 727     return false;
 728
 729   remove_unreferenced_decls ();
 730
 731   timevar_push (TV_VAROUT);
 732
 733   FOR_EACH_VARIABLE (node)
 734     if (!node->definition)
 735       assemble_undefined_decl (node->decl);
 736   FOR_EACH_DEFINED_VARIABLE (node)
 737     {
 738       /* Handled in output_in_order.  */
 739       if (node->no_reorder)
 740         continue;
 741
 742       node->finalize_named_section_flags ();
 743     }
 744
 745   FOR_EACH_DEFINED_VARIABLE (node)
 746     {
 747       /* Handled in output_in_order.  */
 748       if (node->no_reorder)
 749         continue;
 750       if (node->assemble_decl ())
 751         changed = true;
 752     }
 753   timevar_pop (TV_VAROUT);
 754   return changed;
 755 }
 756
 757 /* Create a new global variable of type TYPE.  */
 758 tree
 759 add_new_static_var (tree type)
 760 {
 761   tree new_decl;
 762   varpool_node *new_node;
 763
 764   new_decl = create_tmp_var_raw (type);
 765   DECL_NAME (new_decl) = create_tmp_var_name (NULL);
 766   TREE_READONLY (new_decl) = 0;
 767   TREE_STATIC (new_decl) = 1;
 768   TREE_USED (new_decl) = 1;
 769   DECL_CONTEXT (new_decl) = NULL_TREE;
 770   DECL_ABSTRACT_P (new_decl) = false;
 771   lang_hooks.dup_lang_specific_decl (new_decl);
 772   new_node = varpool_node::get_create (new_decl);
 773   varpool_node::finalize_decl (new_decl);
 774
 775   return new_node->decl;
 776 }
 777
 778 /* Attempt to mark ALIAS as an alias to DECL.  Return TRUE if successful.
 779    Extra name aliases are output whenever DECL is output.  */
 780
 781 varpool_node *
 782 varpool_node::create_alias (tree alias, tree decl)
 783 {
 784   varpool_node *alias_node;
 785
 786   gcc_assert (TREE_CODE (decl) == VAR_DECL);
 787   gcc_assert (TREE_CODE (alias) == VAR_DECL);
 788   alias_node = varpool_node::get_create (alias);
 789   alias_node->alias = true;
 790   alias_node->definition = true;
 791   alias_node->alias_target = decl;
 792   if (lookup_attribute ("weakref", DECL_ATTRIBUTES (alias)) != NULL)
 793     alias_node->weakref = true;
 794   return alias_node;
 795 }
 796
 797 /* Attempt to mark ALIAS as an alias to DECL.  Return TRUE if successful.
 798    Extra name aliases are output whenever DECL is output.  */
 799
 800 varpool_node *
 801 varpool_node::create_extra_name_alias (tree alias, tree decl)
 802 {
 803   varpool_node *alias_node;
 804
 805 #ifndef ASM_OUTPUT_DEF
 806   /* If aliases aren't supported by the assembler, fail.  */
 807   return NULL;
 808 #endif
 809   alias_node = varpool_node::create_alias (alias, decl);
 810   alias_node->cpp_implicit_alias = true;
 811
 812   /* Extra name alias mechanizm creates aliases really late
 813      via DECL_ASSEMBLER_NAME mechanizm.
 814      This is unfortunate because they are not going through the
 815      standard channels.  Ensure they get output.  */
 816   if (symtab->cpp_implicit_aliases_done)
 817     alias_node->resolve_alias (varpool_node::get_create (decl));
 818   return alias_node;
 819 }
 820
 821 /* Worker for call_for_symbol_and_aliases.  */
 822
 823 bool
 824 varpool_node::call_for_symbol_and_aliases_1 (bool (*callback) (varpool_node *,
 825                                                                void *),
 826                                              void *data,
 827                                              bool include_overwritable)
 828 {
 829   ipa_ref *ref;
 830
 831   FOR_EACH_ALIAS (this, ref)
 832     {
 833       varpool_node *alias = dyn_cast <varpool_node *> (ref->referring);
 834       if (include_overwritable
 835           || alias->get_availability () > AVAIL_INTERPOSABLE)
 836         if (alias->call_for_symbol_and_aliases (callback, data,
 837                                                 include_overwritable))
 838           return true;
 839     }
 840   return false;
 841 }