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