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