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