gcc/cgraphbuild.c

   1 /* Callgraph construction.
   2    Copyright (C) 2003-2014 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 "tree.h"
  26 #include "predict.h"
  27 #include "vec.h"
  28 #include "hashtab.h"
  29 #include "hash-set.h"
  30 #include "machmode.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 "hash-map.h"
  49 #include "plugin-api.h"
  50 #include "ipa-ref.h"
  51 #include "cgraph.h"
  52 #include "ipa-utils.h"
  53 #include "except.h"
  54 #include "alloc-pool.h"
  55 #include "symbol-summary.h"
  56 #include "ipa-prop.h"
  57 #include "ipa-inline.h"
  58
  59 /* Context of record_reference.  */
  60 struct record_reference_ctx
  61 {
  62   bool only_vars;
  63   class varpool_node *varpool_node;
  64 };
  65
  66 /* Walk tree and record all calls and references to functions/variables.
  67    Called via walk_tree: TP is pointer to tree to be examined.
  68    When DATA is non-null, record references to callgraph.
  69    */
  70
  71 static tree
  72 record_reference (tree *tp, int *walk_subtrees, void *data)
  73 {
  74   tree t = *tp;
  75   tree decl;
  76   record_reference_ctx *ctx = (record_reference_ctx *)data;
  77
  78   t = canonicalize_constructor_val (t, NULL);
  79   if (!t)
  80     t = *tp;
  81   else if (t != *tp)
  82     *tp = t;
  83
  84   switch (TREE_CODE (t))
  85     {
  86     case VAR_DECL:
  87     case FUNCTION_DECL:
  88       gcc_unreachable ();
  89       break;
  90
  91     case FDESC_EXPR:
  92     case ADDR_EXPR:
  93       /* Record dereferences to the functions.  This makes the
  94          functions reachable unconditionally.  */
  95       decl = get_base_var (*tp);
  96       if (TREE_CODE (decl) == FUNCTION_DECL)
  97         {
  98           cgraph_node *node = cgraph_node::get_create (decl);
  99           if (!ctx->only_vars)
 100             node->mark_address_taken ();
 101           ctx->varpool_node->create_reference (node, IPA_REF_ADDR);
 102         }
 103
 104       if (TREE_CODE (decl) == VAR_DECL)
 105         {
 106           varpool_node *vnode = varpool_node::get_create (decl);
 107           ctx->varpool_node->create_reference (vnode, IPA_REF_ADDR);
 108         }
 109       *walk_subtrees = 0;
 110       break;
 111
 112     default:
 113       /* Save some cycles by not walking types and declaration as we
 114          won't find anything useful there anyway.  */
 115       if (IS_TYPE_OR_DECL_P (*tp))
 116         {
 117           *walk_subtrees = 0;
 118           break;
 119         }
 120       break;
 121     }
 122
 123   return NULL_TREE;
 124 }
 125
 126 /* Record references to typeinfos in the type list LIST.  */
 127
 128 static void
 129 record_type_list (cgraph_node *node, tree list)
 130 {
 131   for (; list; list = TREE_CHAIN (list))
 132     {
 133       tree type = TREE_VALUE (list);
 134
 135       if (TYPE_P (type))
 136         type = lookup_type_for_runtime (type);
 137       STRIP_NOPS (type);
 138       if (TREE_CODE (type) == ADDR_EXPR)
 139         {
 140           type = TREE_OPERAND (type, 0);
 141           if (TREE_CODE (type) == VAR_DECL)
 142             {
 143               varpool_node *vnode = varpool_node::get_create (type);
 144               node->create_reference (vnode, IPA_REF_ADDR);
 145             }
 146         }
 147     }
 148 }
 149
 150 /* Record all references we will introduce by producing EH tables
 151    for NODE.  */
 152
 153 static void
 154 record_eh_tables (cgraph_node *node, function *fun)
 155 {
 156   eh_region i;
 157
 158   if (DECL_FUNCTION_PERSONALITY (node->decl))
 159     {
 160       tree per_decl = DECL_FUNCTION_PERSONALITY (node->decl);
 161       cgraph_node *per_node = cgraph_node::get_create (per_decl);
 162
 163       node->create_reference (per_node, IPA_REF_ADDR);
 164       per_node->mark_address_taken ();
 165     }
 166
 167   i = fun->eh->region_tree;
 168   if (!i)
 169     return;
 170
 171   while (1)
 172     {
 173       switch (i->type)
 174         {
 175         case ERT_CLEANUP:
 176         case ERT_MUST_NOT_THROW:
 177           break;
 178
 179         case ERT_TRY:
 180           {
 181             eh_catch c;
 182             for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
 183               record_type_list (node, c->type_list);
 184           }
 185           break;
 186
 187         case ERT_ALLOWED_EXCEPTIONS:
 188           record_type_list (node, i->u.allowed.type_list);
 189           break;
 190         }
 191       /* If there are sub-regions, process them.  */
 192       if (i->inner)
 193         i = i->inner;
 194       /* If there are peers, process them.  */
 195       else if (i->next_peer)
 196         i = i->next_peer;
 197       /* Otherwise, step back up the tree to the next peer.  */
 198       else
 199         {
 200           do
 201             {
 202               i = i->outer;
 203               if (i == NULL)
 204                 return;
 205             }
 206           while (i->next_peer == NULL);
 207           i = i->next_peer;
 208         }
 209     }
 210 }
 211
 212 /* Computes the frequency of the call statement so that it can be stored in
 213    cgraph_edge.  BB is the basic block of the call statement.  */
 214 int
 215 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 216 {
 217   int entry_freq = ENTRY_BLOCK_PTR_FOR_FN
 218                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 219   int freq = bb->frequency;
 220
 221   if (profile_status_for_fn (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 222     return CGRAPH_FREQ_BASE;
 223
 224   if (!entry_freq)
 225     entry_freq = 1, freq++;
 226
 227   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 228   if (freq > CGRAPH_FREQ_MAX)
 229     freq = CGRAPH_FREQ_MAX;
 230
 231   return freq;
 232 }
 233
 234 /* Mark address taken in STMT.  */
 235
 236 static bool
 237 mark_address (gimple stmt, tree addr, tree, void *data)
 238 {
 239   addr = get_base_address (addr);
 240   if (TREE_CODE (addr) == FUNCTION_DECL)
 241     {
 242       cgraph_node *node = cgraph_node::get_create (addr);
 243       node->mark_address_taken ();
 244       ((symtab_node *)data)->create_reference (node, IPA_REF_ADDR, stmt);
 245     }
 246   else if (addr && TREE_CODE (addr) == VAR_DECL
 247            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 248     {
 249       varpool_node *vnode = varpool_node::get_create (addr);
 250
 251       ((symtab_node *)data)->create_reference (vnode, IPA_REF_ADDR, stmt);
 252     }
 253
 254   return false;
 255 }
 256
 257 /* Mark load of T.  */
 258
 259 static bool
 260 mark_load (gimple stmt, tree t, tree, void *data)
 261 {
 262   t = get_base_address (t);
 263   if (t && TREE_CODE (t) == FUNCTION_DECL)
 264     {
 265       /* ??? This can happen on platforms with descriptors when these are
 266          directly manipulated in the code.  Pretend that it's an address.  */
 267       cgraph_node *node = cgraph_node::get_create (t);
 268       node->mark_address_taken ();
 269       ((symtab_node *)data)->create_reference (node, IPA_REF_ADDR, stmt);
 270     }
 271   else if (t && TREE_CODE (t) == VAR_DECL
 272            && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 273     {
 274       varpool_node *vnode = varpool_node::get_create (t);
 275
 276       ((symtab_node *)data)->create_reference (vnode, IPA_REF_LOAD, stmt);
 277     }
 278   return false;
 279 }
 280
 281 /* Mark store of T.  */
 282
 283 static bool
 284 mark_store (gimple stmt, tree t, tree, void *data)
 285 {
 286   t = get_base_address (t);
 287   if (t && TREE_CODE (t) == VAR_DECL
 288       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 289     {
 290       varpool_node *vnode = varpool_node::get_create (t);
 291
 292       ((symtab_node *)data)->create_reference (vnode, IPA_REF_STORE, stmt);
 293      }
 294   return false;
 295 }
 296
 297 /* Record all references from cgraph_node that are taken in statement STMT.  */
 298
 299 void
 300 cgraph_node::record_stmt_references (gimple stmt)
 301 {
 302   walk_stmt_load_store_addr_ops (stmt, this, mark_load, mark_store,
 303                                  mark_address);
 304 }
 305
 306 /* Create cgraph edges for function calls.
 307    Also look for functions and variables having addresses taken.  */
 308
 309 namespace {
 310
 311 const pass_data pass_data_build_cgraph_edges =
 312 {
 313   GIMPLE_PASS, /* type */
 314   "*build_cgraph_edges", /* name */
 315   OPTGROUP_NONE, /* optinfo_flags */
 316   TV_NONE, /* tv_id */
 317   PROP_cfg, /* properties_required */
 318   0, /* properties_provided */
 319   0, /* properties_destroyed */
 320   0, /* todo_flags_start */
 321   0, /* todo_flags_finish */
 322 };
 323
 324 class pass_build_cgraph_edges : public gimple_opt_pass
 325 {
 326 public:
 327   pass_build_cgraph_edges (gcc::context *ctxt)
 328     : gimple_opt_pass (pass_data_build_cgraph_edges, ctxt)
 329   {}
 330
 331   /* opt_pass methods: */
 332   virtual unsigned int execute (function *);
 333
 334 }; // class pass_build_cgraph_edges
 335
 336 unsigned int
 337 pass_build_cgraph_edges::execute (function *fun)
 338 {
 339   basic_block bb;
 340   cgraph_node *node = cgraph_node::get (current_function_decl);
 341   gimple_stmt_iterator gsi;
 342   tree decl;
 343   unsigned ix;
 344
 345   /* Create the callgraph edges and record the nodes referenced by the function.
 346      body.  */
 347   FOR_EACH_BB_FN (bb, fun)
 348     {
 349       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 350         {
 351           gimple stmt = gsi_stmt (gsi);
 352           tree decl;
 353
 354           if (is_gimple_debug (stmt))
 355             continue;
 356
 357           if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 358             {
 359               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 360                                                          bb);
 361               decl = gimple_call_fndecl (call_stmt);
 362               if (decl)
 363                 node->create_edge (cgraph_node::get_create (decl), call_stmt, bb->count, freq);
 364               else if (gimple_call_internal_p (call_stmt))
 365                 ;
 366               else
 367                 node->create_indirect_edge (call_stmt,
 368                                             gimple_call_flags (call_stmt),
 369                                             bb->count, freq);
 370             }
 371           node->record_stmt_references (stmt);
 372           if (gomp_parallel *omp_par_stmt = dyn_cast <gomp_parallel *> (stmt))
 373             {
 374               tree fn = gimple_omp_parallel_child_fn (omp_par_stmt);
 375               node->create_reference (cgraph_node::get_create (fn),
 376                                       IPA_REF_ADDR, stmt);
 377             }
 378           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 379             {
 380               tree fn = gimple_omp_task_child_fn (stmt);
 381               if (fn)
 382                 node->create_reference (cgraph_node::get_create (fn),
 383                                         IPA_REF_ADDR, stmt);
 384               fn = gimple_omp_task_copy_fn (stmt);
 385               if (fn)
 386                 node->create_reference (cgraph_node::get_create (fn),
 387                                         IPA_REF_ADDR, stmt);
 388             }
 389         }
 390       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 391         node->record_stmt_references (gsi_stmt (gsi));
 392    }
 393
 394   /* Look for initializers of constant variables and private statics.  */
 395   FOR_EACH_LOCAL_DECL (fun, ix, decl)
 396     if (TREE_CODE (decl) == VAR_DECL
 397         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
 398         && !DECL_HAS_VALUE_EXPR_P (decl))
 399       varpool_node::finalize_decl (decl);
 400   record_eh_tables (node, fun);
 401
 402   return 0;
 403 }
 404
 405 } // anon namespace
 406
 407 gimple_opt_pass *
 408 make_pass_build_cgraph_edges (gcc::context *ctxt)
 409 {
 410   return new pass_build_cgraph_edges (ctxt);
 411 }
 412
 413 /* Record references to functions and other variables present in the
 414    initial value of DECL, a variable.
 415    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 416
 417 void
 418 record_references_in_initializer (tree decl, bool only_vars)
 419 {
 420   varpool_node *node = varpool_node::get_create (decl);
 421   hash_set<tree> visited_nodes;
 422   record_reference_ctx ctx = {false, NULL};
 423
 424   ctx.varpool_node = node;
 425   ctx.only_vars = only_vars;
 426   walk_tree (&DECL_INITIAL (decl), record_reference,
 427              &ctx, &visited_nodes);
 428 }
 429
 430 /* Rebuild cgraph edges for current function node.  This needs to be run after
 431    passes that don't update the cgraph.  */
 432
 433 unsigned int
 434 cgraph_edge::rebuild_edges (void)
 435 {
 436   basic_block bb;
 437   cgraph_node *node = cgraph_node::get (current_function_decl);
 438   gimple_stmt_iterator gsi;
 439
 440   node->remove_callees ();
 441   node->remove_all_references ();
 442
 443   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 444
 445   FOR_EACH_BB_FN (bb, cfun)
 446     {
 447       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 448         {
 449           gimple stmt = gsi_stmt (gsi);
 450           tree decl;
 451
 452           if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 453             {
 454               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 455                                                          bb);
 456               decl = gimple_call_fndecl (call_stmt);
 457               if (decl)
 458                 node->create_edge (cgraph_node::get_create (decl), call_stmt,
 459                                    bb->count, freq);
 460               else if (gimple_call_internal_p (call_stmt))
 461                 ;
 462               else
 463                 node->create_indirect_edge (call_stmt,
 464                                             gimple_call_flags (call_stmt),
 465                                             bb->count, freq);
 466             }
 467           node->record_stmt_references (stmt);
 468         }
 469       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 470         node->record_stmt_references (gsi_stmt (gsi));
 471     }
 472   record_eh_tables (node, cfun);
 473   gcc_assert (!node->global.inlined_to);
 474
 475   if (node->instrumented_version
 476       && !node->instrumentation_clone)
 477     node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
 478
 479   return 0;
 480 }
 481
 482 /* Rebuild cgraph references for current function node.  This needs to be run
 483    after passes that don't update the cgraph.  */
 484
 485 void
 486 cgraph_edge::rebuild_references (void)
 487 {
 488   basic_block bb;
 489   cgraph_node *node = cgraph_node::get (current_function_decl);
 490   gimple_stmt_iterator gsi;
 491   ipa_ref *ref = NULL;
 492   int i;
 493
 494   /* Keep speculative references for further cgraph edge expansion.  */
 495   for (i = 0; node->iterate_reference (i, ref);)
 496     if (!ref->speculative)
 497       ref->remove_reference ();
 498     else
 499       i++;
 500
 501   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 502
 503   FOR_EACH_BB_FN (bb, cfun)
 504     {
 505       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 506         node->record_stmt_references (gsi_stmt (gsi));
 507       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 508         node->record_stmt_references (gsi_stmt (gsi));
 509     }
 510   record_eh_tables (node, cfun);
 511
 512   if (node->instrumented_version
 513       && !node->instrumentation_clone)
 514     node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
 515 }
 516
 517 namespace {
 518
 519 const pass_data pass_data_rebuild_cgraph_edges =
 520 {
 521   GIMPLE_PASS, /* type */
 522   "*rebuild_cgraph_edges", /* name */
 523   OPTGROUP_NONE, /* optinfo_flags */
 524   TV_CGRAPH, /* tv_id */
 525   PROP_cfg, /* properties_required */
 526   0, /* properties_provided */
 527   0, /* properties_destroyed */
 528   0, /* todo_flags_start */
 529   0, /* todo_flags_finish */
 530 };
 531
 532 class pass_rebuild_cgraph_edges : public gimple_opt_pass
 533 {
 534 public:
 535   pass_rebuild_cgraph_edges (gcc::context *ctxt)
 536     : gimple_opt_pass (pass_data_rebuild_cgraph_edges, ctxt)
 537   {}
 538
 539   /* opt_pass methods: */
 540   opt_pass * clone () { return new pass_rebuild_cgraph_edges (m_ctxt); }
 541   virtual unsigned int execute (function *)
 542   {
 543     return cgraph_edge::rebuild_edges ();
 544   }
 545
 546 }; // class pass_rebuild_cgraph_edges
 547
 548 } // anon namespace
 549
 550 gimple_opt_pass *
 551 make_pass_rebuild_cgraph_edges (gcc::context *ctxt)
 552 {
 553   return new pass_rebuild_cgraph_edges (ctxt);
 554 }
 555
 556
 557 namespace {
 558
 559 const pass_data pass_data_remove_cgraph_callee_edges =
 560 {
 561   GIMPLE_PASS, /* type */
 562   "*remove_cgraph_callee_edges", /* name */
 563   OPTGROUP_NONE, /* optinfo_flags */
 564   TV_NONE, /* tv_id */
 565   0, /* properties_required */
 566   0, /* properties_provided */
 567   0, /* properties_destroyed */
 568   0, /* todo_flags_start */
 569   0, /* todo_flags_finish */
 570 };
 571
 572 class pass_remove_cgraph_callee_edges : public gimple_opt_pass
 573 {
 574 public:
 575   pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 576     : gimple_opt_pass (pass_data_remove_cgraph_callee_edges, ctxt)
 577   {}
 578
 579   /* opt_pass methods: */
 580   opt_pass * clone () {
 581     return new pass_remove_cgraph_callee_edges (m_ctxt);
 582   }
 583   virtual unsigned int execute (function *);
 584
 585 }; // class pass_remove_cgraph_callee_edges
 586
 587 unsigned int
 588 pass_remove_cgraph_callee_edges::execute (function *)
 589 {
 590   cgraph_node *node = cgraph_node::get (current_function_decl);
 591   node->remove_callees ();
 592   node->remove_all_references ();
 593   return 0;
 594 }
 595
 596 } // anon namespace
 597
 598 gimple_opt_pass *
 599 make_pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 600 {
 601   return new pass_remove_cgraph_callee_edges (ctxt);
 602 }