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 static unsigned int
 309 build_cgraph_edges (void)
 310 {
 311   basic_block bb;
 312   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 313   struct pointer_set_t *visited_nodes = pointer_set_create ();
 314   gimple_stmt_iterator gsi;
 315   tree decl;
 316   unsigned ix;
 317
 318   /* Create the callgraph edges and record the nodes referenced by the function.
 319      body.  */
 320   FOR_EACH_BB_FN (bb, cfun)
 321     {
 322       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 323         {
 324           gimple stmt = gsi_stmt (gsi);
 325           tree decl;
 326
 327           if (is_gimple_debug (stmt))
 328             continue;
 329
 330           if (is_gimple_call (stmt))
 331             {
 332               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 333                                                          bb);
 334               decl = gimple_call_fndecl (stmt);
 335               if (decl)
 336                 cgraph_create_edge (node, cgraph_get_create_node (decl),
 337                                     stmt, bb->count, freq);
 338               else if (gimple_call_internal_p (stmt))
 339                 ;
 340               else
 341                 cgraph_create_indirect_edge (node, stmt,
 342                                              gimple_call_flags (stmt),
 343                                              bb->count, freq);
 344             }
 345           ipa_record_stmt_references (node, stmt);
 346           if (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
 347               && gimple_omp_parallel_child_fn (stmt))
 348             {
 349               tree fn = gimple_omp_parallel_child_fn (stmt);
 350               ipa_record_reference (node,
 351                                     cgraph_get_create_node (fn),
 352                                     IPA_REF_ADDR, stmt);
 353             }
 354           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 355             {
 356               tree fn = gimple_omp_task_child_fn (stmt);
 357               if (fn)
 358                 ipa_record_reference (node,
 359                                       cgraph_get_create_node (fn),
 360                                       IPA_REF_ADDR, stmt);
 361               fn = gimple_omp_task_copy_fn (stmt);
 362               if (fn)
 363                 ipa_record_reference (node,
 364                                       cgraph_get_create_node (fn),
 365                                       IPA_REF_ADDR, stmt);
 366             }
 367         }
 368       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 369         ipa_record_stmt_references (node, gsi_stmt (gsi));
 370    }
 371
 372   /* Look for initializers of constant variables and private statics.  */
 373   FOR_EACH_LOCAL_DECL (cfun, ix, decl)
 374     if (TREE_CODE (decl) == VAR_DECL
 375         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
 376         && !DECL_HAS_VALUE_EXPR_P (decl))
 377       varpool_finalize_decl (decl);
 378   record_eh_tables (node, cfun);
 379
 380   pointer_set_destroy (visited_nodes);
 381   return 0;
 382 }
 383
 384 namespace {
 385
 386 const pass_data pass_data_build_cgraph_edges =
 387 {
 388   GIMPLE_PASS, /* type */
 389   "*build_cgraph_edges", /* name */
 390   OPTGROUP_NONE, /* optinfo_flags */
 391   false, /* has_gate */
 392   true, /* has_execute */
 393   TV_NONE, /* tv_id */
 394   PROP_cfg, /* properties_required */
 395   0, /* properties_provided */
 396   0, /* properties_destroyed */
 397   0, /* todo_flags_start */
 398   0, /* todo_flags_finish */
 399 };
 400
 401 class pass_build_cgraph_edges : public gimple_opt_pass
 402 {
 403 public:
 404   pass_build_cgraph_edges (gcc::context *ctxt)
 405     : gimple_opt_pass (pass_data_build_cgraph_edges, ctxt)
 406   {}
 407
 408   /* opt_pass methods: */
 409   unsigned int execute () { return build_cgraph_edges (); }
 410
 411 }; // class pass_build_cgraph_edges
 412
 413 } // anon namespace
 414
 415 gimple_opt_pass *
 416 make_pass_build_cgraph_edges (gcc::context *ctxt)
 417 {
 418   return new pass_build_cgraph_edges (ctxt);
 419 }
 420
 421 /* Record references to functions and other variables present in the
 422    initial value of DECL, a variable.
 423    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 424
 425 void
 426 record_references_in_initializer (tree decl, bool only_vars)
 427 {
 428   struct pointer_set_t *visited_nodes = pointer_set_create ();
 429   varpool_node *node = varpool_node_for_decl (decl);
 430   struct record_reference_ctx ctx = {false, NULL};
 431
 432   ctx.varpool_node = node;
 433   ctx.only_vars = only_vars;
 434   walk_tree (&DECL_INITIAL (decl), record_reference,
 435              &ctx, visited_nodes);
 436   pointer_set_destroy (visited_nodes);
 437 }
 438
 439 /* Rebuild cgraph edges for current function node.  This needs to be run after
 440    passes that don't update the cgraph.  */
 441
 442 unsigned int
 443 rebuild_cgraph_edges (void)
 444 {
 445   basic_block bb;
 446   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 447   gimple_stmt_iterator gsi;
 448
 449   cgraph_node_remove_callees (node);
 450   ipa_remove_all_references (&node->ref_list);
 451
 452   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 453
 454   FOR_EACH_BB_FN (bb, cfun)
 455     {
 456       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 457         {
 458           gimple stmt = gsi_stmt (gsi);
 459           tree decl;
 460
 461           if (is_gimple_call (stmt))
 462             {
 463               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 464                                                          bb);
 465               decl = gimple_call_fndecl (stmt);
 466               if (decl)
 467                 cgraph_create_edge (node, cgraph_get_create_node (decl), stmt,
 468                                     bb->count, freq);
 469               else if (gimple_call_internal_p (stmt))
 470                 ;
 471               else
 472                 cgraph_create_indirect_edge (node, stmt,
 473                                              gimple_call_flags (stmt),
 474                                              bb->count, freq);
 475             }
 476           ipa_record_stmt_references (node, stmt);
 477         }
 478       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 479         ipa_record_stmt_references (node, gsi_stmt (gsi));
 480     }
 481   record_eh_tables (node, cfun);
 482   gcc_assert (!node->global.inlined_to);
 483
 484   return 0;
 485 }
 486
 487 /* Rebuild cgraph edges for current function node.  This needs to be run after
 488    passes that don't update the cgraph.  */
 489
 490 void
 491 cgraph_rebuild_references (void)
 492 {
 493   basic_block bb;
 494   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 495   gimple_stmt_iterator gsi;
 496   struct ipa_ref *ref;
 497   int i;
 498
 499   /* Keep speculative references for further cgraph edge expansion.  */
 500   for (i = 0; ipa_ref_list_reference_iterate (&node->ref_list, i, ref);)
 501     if (!ref->speculative)
 502       ipa_remove_reference (ref);
 503     else
 504       i++;
 505
 506   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 507
 508   FOR_EACH_BB_FN (bb, cfun)
 509     {
 510       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 511         ipa_record_stmt_references (node, gsi_stmt (gsi));
 512       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 513         ipa_record_stmt_references (node, gsi_stmt (gsi));
 514     }
 515   record_eh_tables (node, cfun);
 516 }
 517
 518 namespace {
 519
 520 const pass_data pass_data_rebuild_cgraph_edges =
 521 {
 522   GIMPLE_PASS, /* type */
 523   "*rebuild_cgraph_edges", /* name */
 524   OPTGROUP_NONE, /* optinfo_flags */
 525   false, /* has_gate */
 526   true, /* has_execute */
 527   TV_CGRAPH, /* tv_id */
 528   PROP_cfg, /* properties_required */
 529   0, /* properties_provided */
 530   0, /* properties_destroyed */
 531   0, /* todo_flags_start */
 532   0, /* todo_flags_finish */
 533 };
 534
 535 class pass_rebuild_cgraph_edges : public gimple_opt_pass
 536 {
 537 public:
 538   pass_rebuild_cgraph_edges (gcc::context *ctxt)
 539     : gimple_opt_pass (pass_data_rebuild_cgraph_edges, ctxt)
 540   {}
 541
 542   /* opt_pass methods: */
 543   opt_pass * clone () { return new pass_rebuild_cgraph_edges (m_ctxt); }
 544   unsigned int execute () { return rebuild_cgraph_edges (); }
 545
 546 }; // class pass_rebuild_cgraph_edges
 547
 548 } // anon namespace
 549
 550 gimple_opt_pass *
 551 make_pass_rebuild_cgraph_edges (gcc::context *ctxt)
 552 {
 553   return new pass_rebuild_cgraph_edges (ctxt);
 554 }
 555
 556
 557 static unsigned int
 558 remove_cgraph_callee_edges (void)
 559 {
 560   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 561   cgraph_node_remove_callees (node);
 562   ipa_remove_all_references (&node->ref_list);
 563   return 0;
 564 }
 565
 566 namespace {
 567
 568 const pass_data pass_data_remove_cgraph_callee_edges =
 569 {
 570   GIMPLE_PASS, /* type */
 571   "*remove_cgraph_callee_edges", /* name */
 572   OPTGROUP_NONE, /* optinfo_flags */
 573   false, /* has_gate */
 574   true, /* has_execute */
 575   TV_NONE, /* tv_id */
 576   0, /* properties_required */
 577   0, /* properties_provided */
 578   0, /* properties_destroyed */
 579   0, /* todo_flags_start */
 580   0, /* todo_flags_finish */
 581 };
 582
 583 class pass_remove_cgraph_callee_edges : public gimple_opt_pass
 584 {
 585 public:
 586   pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 587     : gimple_opt_pass (pass_data_remove_cgraph_callee_edges, ctxt)
 588   {}
 589
 590   /* opt_pass methods: */
 591   opt_pass * clone () {
 592     return new pass_remove_cgraph_callee_edges (m_ctxt);
 593   }
 594   unsigned int execute () { return remove_cgraph_callee_edges (); }
 595
 596 }; // class pass_remove_cgraph_callee_edges
 597
 598 } // anon namespace
 599
 600 gimple_opt_pass *
 601 make_pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 602 {
 603   return new pass_remove_cgraph_callee_edges (ctxt);
 604 }