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