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 "hash-set.h"
  26 #include "machmode.h"
  27 #include "vec.h"
  28 #include "double-int.h"
  29 #include "input.h"
  30 #include "alias.h"
  31 #include "symtab.h"
  32 #include "wide-int.h"
  33 #include "inchash.h"
  34 #include "tree.h"
  35 #include "fold-const.h"
  36 #include "predict.h"
  37 #include "hard-reg-set.h"
  38 #include "input.h"
  39 #include "function.h"
  40 #include "dominance.h"
  41 #include "cfg.h"
  42 #include "basic-block.h"
  43 #include "tree-ssa-alias.h"
  44 #include "internal-fn.h"
  45 #include "gimple-fold.h"
  46 #include "gimple-expr.h"
  47 #include "is-a.h"
  48 #include "gimple.h"
  49 #include "gimple-iterator.h"
  50 #include "gimple-walk.h"
  51 #include "langhooks.h"
  52 #include "intl.h"
  53 #include "tree-pass.h"
  54 #include "hash-map.h"
  55 #include "plugin-api.h"
  56 #include "ipa-ref.h"
  57 #include "cgraph.h"
  58 #include "ipa-utils.h"
  59 #include "except.h"
  60 #include "alloc-pool.h"
  61 #include "symbol-summary.h"
  62 #include "ipa-prop.h"
  63 #include "ipa-inline.h"
  64
  65 /* Context of record_reference.  */
  66 struct record_reference_ctx
  67 {
  68   bool only_vars;
  69   class varpool_node *varpool_node;
  70 };
  71
  72 /* Walk tree and record all calls and references to functions/variables.
  73    Called via walk_tree: TP is pointer to tree to be examined.
  74    When DATA is non-null, record references to callgraph.
  75    */
  76
  77 static tree
  78 record_reference (tree *tp, int *walk_subtrees, void *data)
  79 {
  80   tree t = *tp;
  81   tree decl;
  82   record_reference_ctx *ctx = (record_reference_ctx *)data;
  83
  84   t = canonicalize_constructor_val (t, NULL);
  85   if (!t)
  86     t = *tp;
  87   else if (t != *tp)
  88     *tp = t;
  89
  90   switch (TREE_CODE (t))
  91     {
  92     case VAR_DECL:
  93     case FUNCTION_DECL:
  94       gcc_unreachable ();
  95       break;
  96
  97     case FDESC_EXPR:
  98     case ADDR_EXPR:
  99       /* Record dereferences to the functions.  This makes the
 100          functions reachable unconditionally.  */
 101       decl = get_base_var (*tp);
 102       if (TREE_CODE (decl) == FUNCTION_DECL)
 103         {
 104           cgraph_node *node = cgraph_node::get_create (decl);
 105           if (!ctx->only_vars)
 106             node->mark_address_taken ();
 107           ctx->varpool_node->create_reference (node, IPA_REF_ADDR);
 108         }
 109
 110       if (TREE_CODE (decl) == VAR_DECL)
 111         {
 112           varpool_node *vnode = varpool_node::get_create (decl);
 113           ctx->varpool_node->create_reference (vnode, IPA_REF_ADDR);
 114         }
 115       *walk_subtrees = 0;
 116       break;
 117
 118     default:
 119       /* Save some cycles by not walking types and declaration as we
 120          won't find anything useful there anyway.  */
 121       if (IS_TYPE_OR_DECL_P (*tp))
 122         {
 123           *walk_subtrees = 0;
 124           break;
 125         }
 126       break;
 127     }
 128
 129   return NULL_TREE;
 130 }
 131
 132 /* Record references to typeinfos in the type list LIST.  */
 133
 134 static void
 135 record_type_list (cgraph_node *node, tree list)
 136 {
 137   for (; list; list = TREE_CHAIN (list))
 138     {
 139       tree type = TREE_VALUE (list);
 140
 141       if (TYPE_P (type))
 142         type = lookup_type_for_runtime (type);
 143       STRIP_NOPS (type);
 144       if (TREE_CODE (type) == ADDR_EXPR)
 145         {
 146           type = TREE_OPERAND (type, 0);
 147           if (TREE_CODE (type) == VAR_DECL)
 148             {
 149               varpool_node *vnode = varpool_node::get_create (type);
 150               node->create_reference (vnode, IPA_REF_ADDR);
 151             }
 152         }
 153     }
 154 }
 155
 156 /* Record all references we will introduce by producing EH tables
 157    for NODE.  */
 158
 159 static void
 160 record_eh_tables (cgraph_node *node, function *fun)
 161 {
 162   eh_region i;
 163
 164   if (DECL_FUNCTION_PERSONALITY (node->decl))
 165     {
 166       tree per_decl = DECL_FUNCTION_PERSONALITY (node->decl);
 167       cgraph_node *per_node = cgraph_node::get_create (per_decl);
 168
 169       node->create_reference (per_node, IPA_REF_ADDR);
 170       per_node->mark_address_taken ();
 171     }
 172
 173   i = fun->eh->region_tree;
 174   if (!i)
 175     return;
 176
 177   while (1)
 178     {
 179       switch (i->type)
 180         {
 181         case ERT_CLEANUP:
 182         case ERT_MUST_NOT_THROW:
 183           break;
 184
 185         case ERT_TRY:
 186           {
 187             eh_catch c;
 188             for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
 189               record_type_list (node, c->type_list);
 190           }
 191           break;
 192
 193         case ERT_ALLOWED_EXCEPTIONS:
 194           record_type_list (node, i->u.allowed.type_list);
 195           break;
 196         }
 197       /* If there are sub-regions, process them.  */
 198       if (i->inner)
 199         i = i->inner;
 200       /* If there are peers, process them.  */
 201       else if (i->next_peer)
 202         i = i->next_peer;
 203       /* Otherwise, step back up the tree to the next peer.  */
 204       else
 205         {
 206           do
 207             {
 208               i = i->outer;
 209               if (i == NULL)
 210                 return;
 211             }
 212           while (i->next_peer == NULL);
 213           i = i->next_peer;
 214         }
 215     }
 216 }
 217
 218 /* Computes the frequency of the call statement so that it can be stored in
 219    cgraph_edge.  BB is the basic block of the call statement.  */
 220 int
 221 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 222 {
 223   int entry_freq = ENTRY_BLOCK_PTR_FOR_FN
 224                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 225   int freq = bb->frequency;
 226
 227   if (profile_status_for_fn (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 228     return CGRAPH_FREQ_BASE;
 229
 230   if (!entry_freq)
 231     entry_freq = 1, freq++;
 232
 233   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 234   if (freq > CGRAPH_FREQ_MAX)
 235     freq = CGRAPH_FREQ_MAX;
 236
 237   return freq;
 238 }
 239
 240 /* Mark address taken in STMT.  */
 241
 242 static bool
 243 mark_address (gimple stmt, tree addr, tree, void *data)
 244 {
 245   addr = get_base_address (addr);
 246   if (TREE_CODE (addr) == FUNCTION_DECL)
 247     {
 248       cgraph_node *node = cgraph_node::get_create (addr);
 249       node->mark_address_taken ();
 250       ((symtab_node *)data)->create_reference (node, IPA_REF_ADDR, stmt);
 251     }
 252   else if (addr && TREE_CODE (addr) == VAR_DECL
 253            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 254     {
 255       varpool_node *vnode = varpool_node::get_create (addr);
 256
 257       ((symtab_node *)data)->create_reference (vnode, IPA_REF_ADDR, stmt);
 258     }
 259
 260   return false;
 261 }
 262
 263 /* Mark load of T.  */
 264
 265 static bool
 266 mark_load (gimple stmt, tree t, tree, void *data)
 267 {
 268   t = get_base_address (t);
 269   if (t && TREE_CODE (t) == FUNCTION_DECL)
 270     {
 271       /* ??? This can happen on platforms with descriptors when these are
 272          directly manipulated in the code.  Pretend that it's an address.  */
 273       cgraph_node *node = cgraph_node::get_create (t);
 274       node->mark_address_taken ();
 275       ((symtab_node *)data)->create_reference (node, IPA_REF_ADDR, stmt);
 276     }
 277   else if (t && TREE_CODE (t) == VAR_DECL
 278            && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 279     {
 280       varpool_node *vnode = varpool_node::get_create (t);
 281
 282       ((symtab_node *)data)->create_reference (vnode, IPA_REF_LOAD, stmt);
 283     }
 284   return false;
 285 }
 286
 287 /* Mark store of T.  */
 288
 289 static bool
 290 mark_store (gimple stmt, tree t, tree, void *data)
 291 {
 292   t = get_base_address (t);
 293   if (t && TREE_CODE (t) == VAR_DECL
 294       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 295     {
 296       varpool_node *vnode = varpool_node::get_create (t);
 297
 298       ((symtab_node *)data)->create_reference (vnode, IPA_REF_STORE, stmt);
 299      }
 300   return false;
 301 }
 302
 303 /* Record all references from cgraph_node that are taken in statement STMT.  */
 304
 305 void
 306 cgraph_node::record_stmt_references (gimple stmt)
 307 {
 308   walk_stmt_load_store_addr_ops (stmt, this, mark_load, mark_store,
 309                                  mark_address);
 310 }
 311
 312 /* Create cgraph edges for function calls.
 313    Also look for functions and variables having addresses taken.  */
 314
 315 namespace {
 316
 317 const pass_data pass_data_build_cgraph_edges =
 318 {
 319   GIMPLE_PASS, /* type */
 320   "*build_cgraph_edges", /* name */
 321   OPTGROUP_NONE, /* optinfo_flags */
 322   TV_NONE, /* tv_id */
 323   PROP_cfg, /* properties_required */
 324   0, /* properties_provided */
 325   0, /* properties_destroyed */
 326   0, /* todo_flags_start */
 327   0, /* todo_flags_finish */
 328 };
 329
 330 class pass_build_cgraph_edges : public gimple_opt_pass
 331 {
 332 public:
 333   pass_build_cgraph_edges (gcc::context *ctxt)
 334     : gimple_opt_pass (pass_data_build_cgraph_edges, ctxt)
 335   {}
 336
 337   /* opt_pass methods: */
 338   virtual unsigned int execute (function *);
 339
 340 }; // class pass_build_cgraph_edges
 341
 342 unsigned int
 343 pass_build_cgraph_edges::execute (function *fun)
 344 {
 345   basic_block bb;
 346   cgraph_node *node = cgraph_node::get (current_function_decl);
 347   gimple_stmt_iterator gsi;
 348   tree decl;
 349   unsigned ix;
 350
 351   /* Create the callgraph edges and record the nodes referenced by the function.
 352      body.  */
 353   FOR_EACH_BB_FN (bb, fun)
 354     {
 355       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 356         {
 357           gimple stmt = gsi_stmt (gsi);
 358           tree decl;
 359
 360           if (is_gimple_debug (stmt))
 361             continue;
 362
 363           if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 364             {
 365               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 366                                                          bb);
 367               decl = gimple_call_fndecl (call_stmt);
 368               if (decl)
 369                 node->create_edge (cgraph_node::get_create (decl), call_stmt, bb->count, freq);
 370               else if (gimple_call_internal_p (call_stmt))
 371                 ;
 372               else
 373                 node->create_indirect_edge (call_stmt,
 374                                             gimple_call_flags (call_stmt),
 375                                             bb->count, freq);
 376             }
 377           node->record_stmt_references (stmt);
 378           if (gomp_parallel *omp_par_stmt = dyn_cast <gomp_parallel *> (stmt))
 379             {
 380               tree fn = gimple_omp_parallel_child_fn (omp_par_stmt);
 381               node->create_reference (cgraph_node::get_create (fn),
 382                                       IPA_REF_ADDR, stmt);
 383             }
 384           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 385             {
 386               tree fn = gimple_omp_task_child_fn (stmt);
 387               if (fn)
 388                 node->create_reference (cgraph_node::get_create (fn),
 389                                         IPA_REF_ADDR, stmt);
 390               fn = gimple_omp_task_copy_fn (stmt);
 391               if (fn)
 392                 node->create_reference (cgraph_node::get_create (fn),
 393                                         IPA_REF_ADDR, stmt);
 394             }
 395         }
 396       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 397         node->record_stmt_references (gsi_stmt (gsi));
 398    }
 399
 400   /* Look for initializers of constant variables and private statics.  */
 401   FOR_EACH_LOCAL_DECL (fun, ix, decl)
 402     if (TREE_CODE (decl) == VAR_DECL
 403         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
 404         && !DECL_HAS_VALUE_EXPR_P (decl))
 405       varpool_node::finalize_decl (decl);
 406   record_eh_tables (node, fun);
 407
 408   return 0;
 409 }
 410
 411 } // anon namespace
 412
 413 gimple_opt_pass *
 414 make_pass_build_cgraph_edges (gcc::context *ctxt)
 415 {
 416   return new pass_build_cgraph_edges (ctxt);
 417 }
 418
 419 /* Record references to functions and other variables present in the
 420    initial value of DECL, a variable.
 421    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 422
 423 void
 424 record_references_in_initializer (tree decl, bool only_vars)
 425 {
 426   varpool_node *node = varpool_node::get_create (decl);
 427   hash_set<tree> visited_nodes;
 428   record_reference_ctx ctx = {false, NULL};
 429
 430   ctx.varpool_node = node;
 431   ctx.only_vars = only_vars;
 432   walk_tree (&DECL_INITIAL (decl), record_reference,
 433              &ctx, &visited_nodes);
 434 }
 435
 436 /* Rebuild cgraph edges for current function node.  This needs to be run after
 437    passes that don't update the cgraph.  */
 438
 439 unsigned int
 440 cgraph_edge::rebuild_edges (void)
 441 {
 442   basic_block bb;
 443   cgraph_node *node = cgraph_node::get (current_function_decl);
 444   gimple_stmt_iterator gsi;
 445
 446   node->remove_callees ();
 447   node->remove_all_references ();
 448
 449   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 450
 451   FOR_EACH_BB_FN (bb, cfun)
 452     {
 453       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 454         {
 455           gimple stmt = gsi_stmt (gsi);
 456           tree decl;
 457
 458           if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 459             {
 460               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 461                                                          bb);
 462               decl = gimple_call_fndecl (call_stmt);
 463               if (decl)
 464                 node->create_edge (cgraph_node::get_create (decl), call_stmt,
 465                                    bb->count, freq);
 466               else if (gimple_call_internal_p (call_stmt))
 467                 ;
 468               else
 469                 node->create_indirect_edge (call_stmt,
 470                                             gimple_call_flags (call_stmt),
 471                                             bb->count, freq);
 472             }
 473           node->record_stmt_references (stmt);
 474         }
 475       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 476         node->record_stmt_references (gsi_stmt (gsi));
 477     }
 478   record_eh_tables (node, cfun);
 479   gcc_assert (!node->global.inlined_to);
 480
 481   if (node->instrumented_version
 482       && !node->instrumentation_clone)
 483     node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
 484
 485   return 0;
 486 }
 487
 488 /* Rebuild cgraph references for current function node.  This needs to be run
 489    after passes that don't update the cgraph.  */
 490
 491 void
 492 cgraph_edge::rebuild_references (void)
 493 {
 494   basic_block bb;
 495   cgraph_node *node = cgraph_node::get (current_function_decl);
 496   gimple_stmt_iterator gsi;
 497   ipa_ref *ref = NULL;
 498   int i;
 499
 500   /* Keep speculative references for further cgraph edge expansion.  */
 501   for (i = 0; node->iterate_reference (i, ref);)
 502     if (!ref->speculative)
 503       ref->remove_reference ();
 504     else
 505       i++;
 506
 507   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 508
 509   FOR_EACH_BB_FN (bb, cfun)
 510     {
 511       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 512         node->record_stmt_references (gsi_stmt (gsi));
 513       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 514         node->record_stmt_references (gsi_stmt (gsi));
 515     }
 516   record_eh_tables (node, cfun);
 517
 518   if (node->instrumented_version
 519       && !node->instrumentation_clone)
 520     node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
 521 }
 522
 523 namespace {
 524
 525 const pass_data pass_data_rebuild_cgraph_edges =
 526 {
 527   GIMPLE_PASS, /* type */
 528   "*rebuild_cgraph_edges", /* name */
 529   OPTGROUP_NONE, /* optinfo_flags */
 530   TV_CGRAPH, /* tv_id */
 531   PROP_cfg, /* properties_required */
 532   0, /* properties_provided */
 533   0, /* properties_destroyed */
 534   0, /* todo_flags_start */
 535   0, /* todo_flags_finish */
 536 };
 537
 538 class pass_rebuild_cgraph_edges : public gimple_opt_pass
 539 {
 540 public:
 541   pass_rebuild_cgraph_edges (gcc::context *ctxt)
 542     : gimple_opt_pass (pass_data_rebuild_cgraph_edges, ctxt)
 543   {}
 544
 545   /* opt_pass methods: */
 546   opt_pass * clone () { return new pass_rebuild_cgraph_edges (m_ctxt); }
 547   virtual unsigned int execute (function *)
 548   {
 549     return cgraph_edge::rebuild_edges ();
 550   }
 551
 552 }; // class pass_rebuild_cgraph_edges
 553
 554 } // anon namespace
 555
 556 gimple_opt_pass *
 557 make_pass_rebuild_cgraph_edges (gcc::context *ctxt)
 558 {
 559   return new pass_rebuild_cgraph_edges (ctxt);
 560 }
 561
 562
 563 namespace {
 564
 565 const pass_data pass_data_remove_cgraph_callee_edges =
 566 {
 567   GIMPLE_PASS, /* type */
 568   "*remove_cgraph_callee_edges", /* name */
 569   OPTGROUP_NONE, /* optinfo_flags */
 570   TV_NONE, /* tv_id */
 571   0, /* properties_required */
 572   0, /* properties_provided */
 573   0, /* properties_destroyed */
 574   0, /* todo_flags_start */
 575   0, /* todo_flags_finish */
 576 };
 577
 578 class pass_remove_cgraph_callee_edges : public gimple_opt_pass
 579 {
 580 public:
 581   pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 582     : gimple_opt_pass (pass_data_remove_cgraph_callee_edges, ctxt)
 583   {}
 584
 585   /* opt_pass methods: */
 586   opt_pass * clone () {
 587     return new pass_remove_cgraph_callee_edges (m_ctxt);
 588   }
 589   virtual unsigned int execute (function *);
 590
 591 }; // class pass_remove_cgraph_callee_edges
 592
 593 unsigned int
 594 pass_remove_cgraph_callee_edges::execute (function *)
 595 {
 596   cgraph_node *node = cgraph_node::get (current_function_decl);
 597   node->remove_callees ();
 598   node->remove_all_references ();
 599   return 0;
 600 }
 601
 602 } // anon namespace
 603
 604 gimple_opt_pass *
 605 make_pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 606 {
 607   return new pass_remove_cgraph_callee_edges (ctxt);
 608 }