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