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