gcc/cgraphbuild.c

   1 /* Callgraph construction.
   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 "predict.h"
  31 #include "hard-reg-set.h"
  32 #include "input.h"
  33 #include "function.h"
  34 #include "dominance.h"
  35 #include "cfg.h"
  36 #include "basic-block.h"
  37 #include "tree-ssa-alias.h"
  38 #include "internal-fn.h"
  39 #include "gimple-fold.h"
  40 #include "gimple-expr.h"
  41 #include "is-a.h"
  42 #include "gimple.h"
  43 #include "gimple-iterator.h"
  44 #include "gimple-walk.h"
  45 #include "langhooks.h"
  46 #include "intl.h"
  47 #include "tree-pass.h"
  48 #include "plugin-api.h"
  49 #include "ipa-ref.h"
  50 #include "cgraph.h"
  51 #include "ipa-utils.h"
  52 #include "except.h"
  53 #include "alloc-pool.h"
  54 #include "symbol-summary.h"
  55 #include "ipa-prop.h"
  56 #include "ipa-inline.h"
  57
  58 /* Context of record_reference.  */
  59 struct record_reference_ctx
  60 {
  61   bool only_vars;
  62   class varpool_node *varpool_node;
  63 };
  64
  65 /* Walk tree and record all calls and references to functions/variables.
  66    Called via walk_tree: TP is pointer to tree to be examined.
  67    When DATA is non-null, record references to callgraph.
  68    */
  69
  70 static tree
  71 record_reference (tree *tp, int *walk_subtrees, void *data)
  72 {
  73   tree t = *tp;
  74   tree decl;
  75   record_reference_ctx *ctx = (record_reference_ctx *)data;
  76
  77   t = canonicalize_constructor_val (t, NULL);
  78   if (!t)
  79     t = *tp;
  80   else if (t != *tp)
  81     *tp = t;
  82
  83   switch (TREE_CODE (t))
  84     {
  85     case VAR_DECL:
  86     case FUNCTION_DECL:
  87       gcc_unreachable ();
  88       break;
  89
  90     case FDESC_EXPR:
  91     case ADDR_EXPR:
  92       /* Record dereferences to the functions.  This makes the
  93          functions reachable unconditionally.  */
  94       decl = get_base_var (*tp);
  95       if (TREE_CODE (decl) == FUNCTION_DECL)
  96         {
  97           cgraph_node *node = cgraph_node::get_create (decl);
  98           if (!ctx->only_vars)
  99             node->mark_address_taken ();
 100           ctx->varpool_node->create_reference (node, IPA_REF_ADDR);
 101         }
 102
 103       if (TREE_CODE (decl) == VAR_DECL)
 104         {
 105           varpool_node *vnode = varpool_node::get_create (decl);
 106           ctx->varpool_node->create_reference (vnode, IPA_REF_ADDR);
 107         }
 108       *walk_subtrees = 0;
 109       break;
 110
 111     default:
 112       /* Save some cycles by not walking types and declaration as we
 113          won't find anything useful there anyway.  */
 114       if (IS_TYPE_OR_DECL_P (*tp))
 115         {
 116           *walk_subtrees = 0;
 117           break;
 118         }
 119       break;
 120     }
 121
 122   return NULL_TREE;
 123 }
 124
 125 /* Record references to typeinfos in the type list LIST.  */
 126
 127 static void
 128 record_type_list (cgraph_node *node, tree list)
 129 {
 130   for (; list; list = TREE_CHAIN (list))
 131     {
 132       tree type = TREE_VALUE (list);
 133
 134       if (TYPE_P (type))
 135         type = lookup_type_for_runtime (type);
 136       STRIP_NOPS (type);
 137       if (TREE_CODE (type) == ADDR_EXPR)
 138         {
 139           type = TREE_OPERAND (type, 0);
 140           if (TREE_CODE (type) == VAR_DECL)
 141             {
 142               varpool_node *vnode = varpool_node::get_create (type);
 143               node->create_reference (vnode, IPA_REF_ADDR);
 144             }
 145         }
 146     }
 147 }
 148
 149 /* Record all references we will introduce by producing EH tables
 150    for NODE.  */
 151
 152 static void
 153 record_eh_tables (cgraph_node *node, function *fun)
 154 {
 155   eh_region i;
 156
 157   if (DECL_FUNCTION_PERSONALITY (node->decl))
 158     {
 159       tree per_decl = DECL_FUNCTION_PERSONALITY (node->decl);
 160       cgraph_node *per_node = cgraph_node::get_create (per_decl);
 161
 162       node->create_reference (per_node, IPA_REF_ADDR);
 163       per_node->mark_address_taken ();
 164     }
 165
 166   i = fun->eh->region_tree;
 167   if (!i)
 168     return;
 169
 170   while (1)
 171     {
 172       switch (i->type)
 173         {
 174         case ERT_CLEANUP:
 175         case ERT_MUST_NOT_THROW:
 176           break;
 177
 178         case ERT_TRY:
 179           {
 180             eh_catch c;
 181             for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
 182               record_type_list (node, c->type_list);
 183           }
 184           break;
 185
 186         case ERT_ALLOWED_EXCEPTIONS:
 187           record_type_list (node, i->u.allowed.type_list);
 188           break;
 189         }
 190       /* If there are sub-regions, process them.  */
 191       if (i->inner)
 192         i = i->inner;
 193       /* If there are peers, process them.  */
 194       else if (i->next_peer)
 195         i = i->next_peer;
 196       /* Otherwise, step back up the tree to the next peer.  */
 197       else
 198         {
 199           do
 200             {
 201               i = i->outer;
 202               if (i == NULL)
 203                 return;
 204             }
 205           while (i->next_peer == NULL);
 206           i = i->next_peer;
 207         }
 208     }
 209 }
 210
 211 /* Computes the frequency of the call statement so that it can be stored in
 212    cgraph_edge.  BB is the basic block of the call statement.  */
 213 int
 214 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 215 {
 216   int entry_freq = ENTRY_BLOCK_PTR_FOR_FN
 217                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 218   int freq = bb->frequency;
 219
 220   if (profile_status_for_fn (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 221     return CGRAPH_FREQ_BASE;
 222
 223   if (!entry_freq)
 224     entry_freq = 1, freq++;
 225
 226   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 227   if (freq > CGRAPH_FREQ_MAX)
 228     freq = CGRAPH_FREQ_MAX;
 229
 230   return freq;
 231 }
 232
 233 /* Mark address taken in STMT.  */
 234
 235 static bool
 236 mark_address (gimple stmt, tree addr, tree, void *data)
 237 {
 238   addr = get_base_address (addr);
 239   if (TREE_CODE (addr) == FUNCTION_DECL)
 240     {
 241       cgraph_node *node = cgraph_node::get_create (addr);
 242       node->mark_address_taken ();
 243       ((symtab_node *)data)->create_reference (node, IPA_REF_ADDR, stmt);
 244     }
 245   else if (addr && TREE_CODE (addr) == VAR_DECL
 246            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 247     {
 248       varpool_node *vnode = varpool_node::get_create (addr);
 249
 250       ((symtab_node *)data)->create_reference (vnode, IPA_REF_ADDR, stmt);
 251     }
 252
 253   return false;
 254 }
 255
 256 /* Mark load of T.  */
 257
 258 static bool
 259 mark_load (gimple stmt, tree t, tree, void *data)
 260 {
 261   t = get_base_address (t);
 262   if (t && TREE_CODE (t) == FUNCTION_DECL)
 263     {
 264       /* ??? This can happen on platforms with descriptors when these are
 265          directly manipulated in the code.  Pretend that it's an address.  */
 266       cgraph_node *node = cgraph_node::get_create (t);
 267       node->mark_address_taken ();
 268       ((symtab_node *)data)->create_reference (node, IPA_REF_ADDR, stmt);
 269     }
 270   else if (t && TREE_CODE (t) == VAR_DECL
 271            && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 272     {
 273       varpool_node *vnode = varpool_node::get_create (t);
 274
 275       ((symtab_node *)data)->create_reference (vnode, IPA_REF_LOAD, stmt);
 276     }
 277   return false;
 278 }
 279
 280 /* Mark store of T.  */
 281
 282 static bool
 283 mark_store (gimple stmt, tree t, tree, void *data)
 284 {
 285   t = get_base_address (t);
 286   if (t && TREE_CODE (t) == VAR_DECL
 287       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 288     {
 289       varpool_node *vnode = varpool_node::get_create (t);
 290
 291       ((symtab_node *)data)->create_reference (vnode, IPA_REF_STORE, stmt);
 292      }
 293   return false;
 294 }
 295
 296 /* Record all references from cgraph_node that are taken in statement STMT.  */
 297
 298 void
 299 cgraph_node::record_stmt_references (gimple stmt)
 300 {
 301   walk_stmt_load_store_addr_ops (stmt, this, mark_load, mark_store,
 302                                  mark_address);
 303 }
 304
 305 /* Create cgraph edges for function calls.
 306    Also look for functions and variables having addresses taken.  */
 307
 308 namespace {
 309
 310 const pass_data pass_data_build_cgraph_edges =
 311 {
 312   GIMPLE_PASS, /* type */
 313   "*build_cgraph_edges", /* name */
 314   OPTGROUP_NONE, /* optinfo_flags */
 315   TV_NONE, /* tv_id */
 316   PROP_cfg, /* properties_required */
 317   0, /* properties_provided */
 318   0, /* properties_destroyed */
 319   0, /* todo_flags_start */
 320   0, /* todo_flags_finish */
 321 };
 322
 323 class pass_build_cgraph_edges : public gimple_opt_pass
 324 {
 325 public:
 326   pass_build_cgraph_edges (gcc::context *ctxt)
 327     : gimple_opt_pass (pass_data_build_cgraph_edges, ctxt)
 328   {}
 329
 330   /* opt_pass methods: */
 331   virtual unsigned int execute (function *);
 332
 333 }; // class pass_build_cgraph_edges
 334
 335 unsigned int
 336 pass_build_cgraph_edges::execute (function *fun)
 337 {
 338   basic_block bb;
 339   cgraph_node *node = cgraph_node::get (current_function_decl);
 340   gimple_stmt_iterator gsi;
 341   tree decl;
 342   unsigned ix;
 343
 344   /* Create the callgraph edges and record the nodes referenced by the function.
 345      body.  */
 346   FOR_EACH_BB_FN (bb, fun)
 347     {
 348       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 349         {
 350           gimple stmt = gsi_stmt (gsi);
 351           tree decl;
 352
 353           if (is_gimple_debug (stmt))
 354             continue;
 355
 356           if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 357             {
 358               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 359                                                          bb);
 360               decl = gimple_call_fndecl (call_stmt);
 361               if (decl)
 362                 node->create_edge (cgraph_node::get_create (decl), call_stmt, bb->count, freq);
 363               else if (gimple_call_internal_p (call_stmt))
 364                 ;
 365               else
 366                 node->create_indirect_edge (call_stmt,
 367                                             gimple_call_flags (call_stmt),
 368                                             bb->count, freq);
 369             }
 370           node->record_stmt_references (stmt);
 371           if (gomp_parallel *omp_par_stmt = dyn_cast <gomp_parallel *> (stmt))
 372             {
 373               tree fn = gimple_omp_parallel_child_fn (omp_par_stmt);
 374               node->create_reference (cgraph_node::get_create (fn),
 375                                       IPA_REF_ADDR, stmt);
 376             }
 377           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 378             {
 379               tree fn = gimple_omp_task_child_fn (stmt);
 380               if (fn)
 381                 node->create_reference (cgraph_node::get_create (fn),
 382                                         IPA_REF_ADDR, stmt);
 383               fn = gimple_omp_task_copy_fn (stmt);
 384               if (fn)
 385                 node->create_reference (cgraph_node::get_create (fn),
 386                                         IPA_REF_ADDR, stmt);
 387             }
 388         }
 389       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 390         node->record_stmt_references (gsi_stmt (gsi));
 391    }
 392
 393   /* Look for initializers of constant variables and private statics.  */
 394   FOR_EACH_LOCAL_DECL (fun, ix, decl)
 395     if (TREE_CODE (decl) == VAR_DECL
 396         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
 397         && !DECL_HAS_VALUE_EXPR_P (decl))
 398       varpool_node::finalize_decl (decl);
 399   record_eh_tables (node, fun);
 400
 401   return 0;
 402 }
 403
 404 } // anon namespace
 405
 406 gimple_opt_pass *
 407 make_pass_build_cgraph_edges (gcc::context *ctxt)
 408 {
 409   return new pass_build_cgraph_edges (ctxt);
 410 }
 411
 412 /* Record references to functions and other variables present in the
 413    initial value of DECL, a variable.
 414    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 415
 416 void
 417 record_references_in_initializer (tree decl, bool only_vars)
 418 {
 419   varpool_node *node = varpool_node::get_create (decl);
 420   hash_set<tree> visited_nodes;
 421   record_reference_ctx ctx = {false, NULL};
 422
 423   ctx.varpool_node = node;
 424   ctx.only_vars = only_vars;
 425   walk_tree (&DECL_INITIAL (decl), record_reference,
 426              &ctx, &visited_nodes);
 427 }
 428
 429 /* Rebuild cgraph edges for current function node.  This needs to be run after
 430    passes that don't update the cgraph.  */
 431
 432 unsigned int
 433 cgraph_edge::rebuild_edges (void)
 434 {
 435   basic_block bb;
 436   cgraph_node *node = cgraph_node::get (current_function_decl);
 437   gimple_stmt_iterator gsi;
 438
 439   node->remove_callees ();
 440   node->remove_all_references ();
 441
 442   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 443
 444   FOR_EACH_BB_FN (bb, cfun)
 445     {
 446       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 447         {
 448           gimple stmt = gsi_stmt (gsi);
 449           tree decl;
 450
 451           if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 452             {
 453               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 454                                                          bb);
 455               decl = gimple_call_fndecl (call_stmt);
 456               if (decl)
 457                 node->create_edge (cgraph_node::get_create (decl), call_stmt,
 458                                    bb->count, freq);
 459               else if (gimple_call_internal_p (call_stmt))
 460                 ;
 461               else
 462                 node->create_indirect_edge (call_stmt,
 463                                             gimple_call_flags (call_stmt),
 464                                             bb->count, freq);
 465             }
 466           node->record_stmt_references (stmt);
 467         }
 468       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 469         node->record_stmt_references (gsi_stmt (gsi));
 470     }
 471   record_eh_tables (node, cfun);
 472   gcc_assert (!node->global.inlined_to);
 473
 474   if (node->instrumented_version
 475       && !node->instrumentation_clone)
 476     node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
 477
 478   return 0;
 479 }
 480
 481 /* Rebuild cgraph references for current function node.  This needs to be run
 482    after passes that don't update the cgraph.  */
 483
 484 void
 485 cgraph_edge::rebuild_references (void)
 486 {
 487   basic_block bb;
 488   cgraph_node *node = cgraph_node::get (current_function_decl);
 489   gimple_stmt_iterator gsi;
 490   ipa_ref *ref = NULL;
 491   int i;
 492
 493   /* Keep speculative references for further cgraph edge expansion.  */
 494   for (i = 0; node->iterate_reference (i, ref);)
 495     if (!ref->speculative)
 496       ref->remove_reference ();
 497     else
 498       i++;
 499
 500   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 501
 502   FOR_EACH_BB_FN (bb, cfun)
 503     {
 504       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 505         node->record_stmt_references (gsi_stmt (gsi));
 506       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 507         node->record_stmt_references (gsi_stmt (gsi));
 508     }
 509   record_eh_tables (node, cfun);
 510
 511   if (node->instrumented_version
 512       && !node->instrumentation_clone)
 513     node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
 514 }
 515
 516 namespace {
 517
 518 const pass_data pass_data_rebuild_cgraph_edges =
 519 {
 520   GIMPLE_PASS, /* type */
 521   "*rebuild_cgraph_edges", /* name */
 522   OPTGROUP_NONE, /* optinfo_flags */
 523   TV_CGRAPH, /* tv_id */
 524   PROP_cfg, /* properties_required */
 525   0, /* properties_provided */
 526   0, /* properties_destroyed */
 527   0, /* todo_flags_start */
 528   0, /* todo_flags_finish */
 529 };
 530
 531 class pass_rebuild_cgraph_edges : public gimple_opt_pass
 532 {
 533 public:
 534   pass_rebuild_cgraph_edges (gcc::context *ctxt)
 535     : gimple_opt_pass (pass_data_rebuild_cgraph_edges, ctxt)
 536   {}
 537
 538   /* opt_pass methods: */
 539   opt_pass * clone () { return new pass_rebuild_cgraph_edges (m_ctxt); }
 540   virtual unsigned int execute (function *)
 541   {
 542     return cgraph_edge::rebuild_edges ();
 543   }
 544
 545 }; // class pass_rebuild_cgraph_edges
 546
 547 } // anon namespace
 548
 549 gimple_opt_pass *
 550 make_pass_rebuild_cgraph_edges (gcc::context *ctxt)
 551 {
 552   return new pass_rebuild_cgraph_edges (ctxt);
 553 }
 554
 555
 556 namespace {
 557
 558 const pass_data pass_data_remove_cgraph_callee_edges =
 559 {
 560   GIMPLE_PASS, /* type */
 561   "*remove_cgraph_callee_edges", /* name */
 562   OPTGROUP_NONE, /* optinfo_flags */
 563   TV_NONE, /* tv_id */
 564   0, /* properties_required */
 565   0, /* properties_provided */
 566   0, /* properties_destroyed */
 567   0, /* todo_flags_start */
 568   0, /* todo_flags_finish */
 569 };
 570
 571 class pass_remove_cgraph_callee_edges : public gimple_opt_pass
 572 {
 573 public:
 574   pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 575     : gimple_opt_pass (pass_data_remove_cgraph_callee_edges, ctxt)
 576   {}
 577
 578   /* opt_pass methods: */
 579   opt_pass * clone () {
 580     return new pass_remove_cgraph_callee_edges (m_ctxt);
 581   }
 582   virtual unsigned int execute (function *);
 583
 584 }; // class pass_remove_cgraph_callee_edges
 585
 586 unsigned int
 587 pass_remove_cgraph_callee_edges::execute (function *)
 588 {
 589   cgraph_node *node = cgraph_node::get (current_function_decl);
 590   node->remove_callees ();
 591   node->remove_all_references ();
 592   return 0;
 593 }
 594
 595 } // anon namespace
 596
 597 gimple_opt_pass *
 598 make_pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 599 {
 600   return new pass_remove_cgraph_callee_edges (ctxt);
 601 }