gcc/cgraphbuild.c

   1 /* Callgraph construction.
   2    Copyright (C) 2003-2013 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 "tree-ssa.h"
  27 #include "langhooks.h"
  28 #include "pointer-set.h"
  29 #include "cgraph.h"
  30 #include "intl.h"
  31 #include "gimple.h"
  32 #include "tree-pass.h"
  33 #include "ipa-utils.h"
  34 #include "except.h"
  35 #include "ipa-inline.h"
  36
  37 /* Context of record_reference.  */
  38 struct record_reference_ctx
  39 {
  40   bool only_vars;
  41   struct varpool_node *varpool_node;
  42 };
  43
  44 /* Walk tree and record all calls and references to functions/variables.
  45    Called via walk_tree: TP is pointer to tree to be examined.
  46    When DATA is non-null, record references to callgraph.
  47    */
  48
  49 static tree
  50 record_reference (tree *tp, int *walk_subtrees, void *data)
  51 {
  52   tree t = *tp;
  53   tree decl;
  54   struct record_reference_ctx *ctx = (struct record_reference_ctx *)data;
  55
  56   t = canonicalize_constructor_val (t, NULL);
  57   if (!t)
  58     t = *tp;
  59   else if (t != *tp)
  60     *tp = t;
  61
  62   switch (TREE_CODE (t))
  63     {
  64     case VAR_DECL:
  65     case FUNCTION_DECL:
  66       gcc_unreachable ();
  67       break;
  68
  69     case FDESC_EXPR:
  70     case ADDR_EXPR:
  71       /* Record dereferences to the functions.  This makes the
  72          functions reachable unconditionally.  */
  73       decl = get_base_var (*tp);
  74       if (TREE_CODE (decl) == FUNCTION_DECL)
  75         {
  76           struct cgraph_node *node = cgraph_get_create_real_symbol_node (decl);
  77           if (!ctx->only_vars)
  78             cgraph_mark_address_taken_node (node);
  79           ipa_record_reference ((symtab_node)ctx->varpool_node,
  80                                 (symtab_node)node,
  81                                 IPA_REF_ADDR, NULL);
  82         }
  83
  84       if (TREE_CODE (decl) == VAR_DECL)
  85         {
  86           struct varpool_node *vnode = varpool_node_for_decl (decl);
  87           ipa_record_reference ((symtab_node)ctx->varpool_node,
  88                                 (symtab_node)vnode,
  89                                 IPA_REF_ADDR, NULL);
  90         }
  91       *walk_subtrees = 0;
  92       break;
  93
  94     default:
  95       /* Save some cycles by not walking types and declaration as we
  96          won't find anything useful there anyway.  */
  97       if (IS_TYPE_OR_DECL_P (*tp))
  98         {
  99           *walk_subtrees = 0;
 100           break;
 101         }
 102       break;
 103     }
 104
 105   return NULL_TREE;
 106 }
 107
 108 /* Record references to typeinfos in the type list LIST.  */
 109
 110 static void
 111 record_type_list (struct cgraph_node *node, tree list)
 112 {
 113   for (; list; list = TREE_CHAIN (list))
 114     {
 115       tree type = TREE_VALUE (list);
 116
 117       if (TYPE_P (type))
 118         type = lookup_type_for_runtime (type);
 119       STRIP_NOPS (type);
 120       if (TREE_CODE (type) == ADDR_EXPR)
 121         {
 122           type = TREE_OPERAND (type, 0);
 123           if (TREE_CODE (type) == VAR_DECL)
 124             {
 125               struct varpool_node *vnode = varpool_node_for_decl (type);
 126               ipa_record_reference ((symtab_node)node,
 127                                     (symtab_node)vnode,
 128                                     IPA_REF_ADDR, NULL);
 129             }
 130         }
 131     }
 132 }
 133
 134 /* Record all references we will introduce by producing EH tables
 135    for NODE.  */
 136
 137 static void
 138 record_eh_tables (struct cgraph_node *node, struct function *fun)
 139 {
 140   eh_region i;
 141
 142   if (DECL_FUNCTION_PERSONALITY (node->symbol.decl))
 143     {
 144       struct cgraph_node *per_node;
 145
 146       per_node = cgraph_get_create_real_symbol_node (DECL_FUNCTION_PERSONALITY (node->symbol.decl));
 147       ipa_record_reference ((symtab_node)node, (symtab_node)per_node, IPA_REF_ADDR, NULL);
 148       cgraph_mark_address_taken_node (per_node);
 149     }
 150
 151   i = fun->eh->region_tree;
 152   if (!i)
 153     return;
 154
 155   while (1)
 156     {
 157       switch (i->type)
 158         {
 159         case ERT_CLEANUP:
 160         case ERT_MUST_NOT_THROW:
 161           break;
 162
 163         case ERT_TRY:
 164           {
 165             eh_catch c;
 166             for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
 167               record_type_list (node, c->type_list);
 168           }
 169           break;
 170
 171         case ERT_ALLOWED_EXCEPTIONS:
 172           record_type_list (node, i->u.allowed.type_list);
 173           break;
 174         }
 175       /* If there are sub-regions, process them.  */
 176       if (i->inner)
 177         i = i->inner;
 178       /* If there are peers, process them.  */
 179       else if (i->next_peer)
 180         i = i->next_peer;
 181       /* Otherwise, step back up the tree to the next peer.  */
 182       else
 183         {
 184           do
 185             {
 186               i = i->outer;
 187               if (i == NULL)
 188                 return;
 189             }
 190           while (i->next_peer == NULL);
 191           i = i->next_peer;
 192         }
 193     }
 194 }
 195
 196 /* Computes the frequency of the call statement so that it can be stored in
 197    cgraph_edge.  BB is the basic block of the call statement.  */
 198 int
 199 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 200 {
 201   int entry_freq = ENTRY_BLOCK_PTR_FOR_FUNCTION
 202                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 203   int freq = bb->frequency;
 204
 205   if (profile_status_for_function (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 206     return CGRAPH_FREQ_BASE;
 207
 208   if (!entry_freq)
 209     entry_freq = 1, freq++;
 210
 211   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 212   if (freq > CGRAPH_FREQ_MAX)
 213     freq = CGRAPH_FREQ_MAX;
 214
 215   return freq;
 216 }
 217
 218 /* Mark address taken in STMT.  */
 219
 220 static bool
 221 mark_address (gimple stmt, tree addr, void *data)
 222 {
 223   addr = get_base_address (addr);
 224   if (TREE_CODE (addr) == FUNCTION_DECL)
 225     {
 226       struct cgraph_node *node = cgraph_get_create_real_symbol_node (addr);
 227       cgraph_mark_address_taken_node (node);
 228       ipa_record_reference ((symtab_node)data,
 229                             (symtab_node)node,
 230                             IPA_REF_ADDR, stmt);
 231     }
 232   else if (addr && TREE_CODE (addr) == VAR_DECL
 233            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 234     {
 235       struct varpool_node *vnode = varpool_node_for_decl (addr);
 236
 237       ipa_record_reference ((symtab_node)data,
 238                             (symtab_node)vnode,
 239                             IPA_REF_ADDR, stmt);
 240     }
 241
 242   return false;
 243 }
 244
 245 /* Mark load of T.  */
 246
 247 static bool
 248 mark_load (gimple stmt, tree t, void *data)
 249 {
 250   t = get_base_address (t);
 251   if (t && TREE_CODE (t) == FUNCTION_DECL)
 252     {
 253       /* ??? This can happen on platforms with descriptors when these are
 254          directly manipulated in the code.  Pretend that it's an address.  */
 255       struct cgraph_node *node = cgraph_get_create_real_symbol_node (t);
 256       cgraph_mark_address_taken_node (node);
 257       ipa_record_reference ((symtab_node)data,
 258                             (symtab_node)node,
 259                             IPA_REF_ADDR, stmt);
 260     }
 261   else if (t && TREE_CODE (t) == VAR_DECL
 262            && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 263     {
 264       struct varpool_node *vnode = varpool_node_for_decl (t);
 265
 266       ipa_record_reference ((symtab_node)data,
 267                             (symtab_node)vnode,
 268                             IPA_REF_LOAD, stmt);
 269     }
 270   return false;
 271 }
 272
 273 /* Mark store of T.  */
 274
 275 static bool
 276 mark_store (gimple stmt, tree t, void *data)
 277 {
 278   t = get_base_address (t);
 279   if (t && TREE_CODE (t) == VAR_DECL
 280       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 281     {
 282       struct varpool_node *vnode = varpool_node_for_decl (t);
 283
 284       ipa_record_reference ((symtab_node)data,
 285                             (symtab_node)vnode,
 286                             IPA_REF_STORE, stmt);
 287      }
 288   return false;
 289 }
 290
 291 /* Record all references from NODE that are taken in statement STMT.  */
 292 void
 293 ipa_record_stmt_references (struct cgraph_node *node, gimple stmt)
 294 {
 295   walk_stmt_load_store_addr_ops (stmt, node, mark_load, mark_store,
 296                                  mark_address);
 297 }
 298
 299 /* Create cgraph edges for function calls.
 300    Also look for functions and variables having addresses taken.  */
 301
 302 static unsigned int
 303 build_cgraph_edges (void)
 304 {
 305   basic_block bb;
 306   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 307   struct pointer_set_t *visited_nodes = pointer_set_create ();
 308   gimple_stmt_iterator gsi;
 309   tree decl;
 310   unsigned ix;
 311
 312   /* Create the callgraph edges and record the nodes referenced by the function.
 313      body.  */
 314   FOR_EACH_BB (bb)
 315     {
 316       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 317         {
 318           gimple stmt = gsi_stmt (gsi);
 319           tree decl;
 320
 321           if (is_gimple_debug (stmt))
 322             continue;
 323
 324           if (is_gimple_call (stmt))
 325             {
 326               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 327                                                          bb);
 328               decl = gimple_call_fndecl (stmt);
 329               if (decl)
 330                 cgraph_create_edge (node, cgraph_get_create_node (decl),
 331                                     stmt, bb->count, freq);
 332               else
 333                 cgraph_create_indirect_edge (node, stmt,
 334                                              gimple_call_flags (stmt),
 335                                              bb->count, freq);
 336             }
 337           ipa_record_stmt_references (node, stmt);
 338           if (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
 339               && gimple_omp_parallel_child_fn (stmt))
 340             {
 341               tree fn = gimple_omp_parallel_child_fn (stmt);
 342               ipa_record_reference ((symtab_node)node,
 343                                     (symtab_node)cgraph_get_create_real_symbol_node (fn),
 344                                     IPA_REF_ADDR, stmt);
 345             }
 346           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 347             {
 348               tree fn = gimple_omp_task_child_fn (stmt);
 349               if (fn)
 350                 ipa_record_reference ((symtab_node)node,
 351                                       (symtab_node) cgraph_get_create_real_symbol_node (fn),
 352                                       IPA_REF_ADDR, stmt);
 353               fn = gimple_omp_task_copy_fn (stmt);
 354               if (fn)
 355                 ipa_record_reference ((symtab_node)node,
 356                                       (symtab_node)cgraph_get_create_real_symbol_node (fn),
 357                                       IPA_REF_ADDR, stmt);
 358             }
 359         }
 360       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 361         ipa_record_stmt_references (node, gsi_stmt (gsi));
 362    }
 363
 364   /* Look for initializers of constant variables and private statics.  */
 365   FOR_EACH_LOCAL_DECL (cfun, ix, decl)
 366     if (TREE_CODE (decl) == VAR_DECL
 367         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
 368         && !DECL_HAS_VALUE_EXPR_P (decl))
 369       varpool_finalize_decl (decl);
 370   record_eh_tables (node, cfun);
 371
 372   pointer_set_destroy (visited_nodes);
 373   return 0;
 374 }
 375
 376 namespace {
 377
 378 const pass_data pass_data_build_cgraph_edges =
 379 {
 380   GIMPLE_PASS, /* type */
 381   "*build_cgraph_edges", /* name */
 382   OPTGROUP_NONE, /* optinfo_flags */
 383   false, /* has_gate */
 384   true, /* has_execute */
 385   TV_NONE, /* tv_id */
 386   PROP_cfg, /* properties_required */
 387   0, /* properties_provided */
 388   0, /* properties_destroyed */
 389   0, /* todo_flags_start */
 390   0, /* todo_flags_finish */
 391 };
 392
 393 class pass_build_cgraph_edges : public gimple_opt_pass
 394 {
 395 public:
 396   pass_build_cgraph_edges(gcc::context *ctxt)
 397     : gimple_opt_pass(pass_data_build_cgraph_edges, ctxt)
 398   {}
 399
 400   /* opt_pass methods: */
 401   unsigned int execute () { return build_cgraph_edges (); }
 402
 403 }; // class pass_build_cgraph_edges
 404
 405 } // anon namespace
 406
 407 gimple_opt_pass *
 408 make_pass_build_cgraph_edges (gcc::context *ctxt)
 409 {
 410   return new pass_build_cgraph_edges (ctxt);
 411 }
 412
 413 /* Record references to functions and other variables present in the
 414    initial value of DECL, a variable.
 415    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 416
 417 void
 418 record_references_in_initializer (tree decl, bool only_vars)
 419 {
 420   struct pointer_set_t *visited_nodes = pointer_set_create ();
 421   struct varpool_node *node = varpool_node_for_decl (decl);
 422   struct record_reference_ctx ctx = {false, NULL};
 423
 424   ctx.varpool_node = node;
 425   ctx.only_vars = only_vars;
 426   walk_tree (&DECL_INITIAL (decl), record_reference,
 427              &ctx, visited_nodes);
 428   pointer_set_destroy (visited_nodes);
 429 }
 430
 431 /* Rebuild cgraph edges for current function node.  This needs to be run after
 432    passes that don't update the cgraph.  */
 433
 434 unsigned int
 435 rebuild_cgraph_edges (void)
 436 {
 437   basic_block bb;
 438   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 439   gimple_stmt_iterator gsi;
 440
 441   cgraph_node_remove_callees (node);
 442   ipa_remove_all_references (&node->symbol.ref_list);
 443
 444   node->count = ENTRY_BLOCK_PTR->count;
 445
 446   FOR_EACH_BB (bb)
 447     {
 448       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 449         {
 450           gimple stmt = gsi_stmt (gsi);
 451           tree decl;
 452
 453           if (is_gimple_call (stmt))
 454             {
 455               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 456                                                          bb);
 457               decl = gimple_call_fndecl (stmt);
 458               if (decl)
 459                 cgraph_create_edge (node, cgraph_get_create_node (decl), stmt,
 460                                     bb->count, freq);
 461               else
 462                 cgraph_create_indirect_edge (node, stmt,
 463                                              gimple_call_flags (stmt),
 464                                              bb->count, freq);
 465             }
 466           ipa_record_stmt_references (node, stmt);
 467         }
 468       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 469         ipa_record_stmt_references (node, gsi_stmt (gsi));
 470     }
 471   record_eh_tables (node, cfun);
 472   gcc_assert (!node->global.inlined_to);
 473
 474   return 0;
 475 }
 476
 477 /* Rebuild cgraph edges for current function node.  This needs to be run after
 478    passes that don't update the cgraph.  */
 479
 480 void
 481 cgraph_rebuild_references (void)
 482 {
 483   basic_block bb;
 484   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 485   gimple_stmt_iterator gsi;
 486   struct ipa_ref *ref;
 487   int i;
 488
 489   /* Keep speculative references for further cgraph edge expansion.  */
 490   for (i = 0; ipa_ref_list_reference_iterate (&node->symbol.ref_list, i, ref);)
 491     if (!ref->speculative)
 492       ipa_remove_reference (ref);
 493     else
 494       i++;
 495
 496   node->count = ENTRY_BLOCK_PTR->count;
 497
 498   FOR_EACH_BB (bb)
 499     {
 500       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 501         ipa_record_stmt_references (node, gsi_stmt (gsi));
 502       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 503         ipa_record_stmt_references (node, gsi_stmt (gsi));
 504     }
 505   record_eh_tables (node, cfun);
 506 }
 507
 508 namespace {
 509
 510 const pass_data pass_data_rebuild_cgraph_edges =
 511 {
 512   GIMPLE_PASS, /* type */
 513   "*rebuild_cgraph_edges", /* name */
 514   OPTGROUP_NONE, /* optinfo_flags */
 515   false, /* has_gate */
 516   true, /* has_execute */
 517   TV_CGRAPH, /* tv_id */
 518   PROP_cfg, /* properties_required */
 519   0, /* properties_provided */
 520   0, /* properties_destroyed */
 521   0, /* todo_flags_start */
 522   0, /* todo_flags_finish */
 523 };
 524
 525 class pass_rebuild_cgraph_edges : public gimple_opt_pass
 526 {
 527 public:
 528   pass_rebuild_cgraph_edges(gcc::context *ctxt)
 529     : gimple_opt_pass(pass_data_rebuild_cgraph_edges, ctxt)
 530   {}
 531
 532   /* opt_pass methods: */
 533   opt_pass * clone () { return new pass_rebuild_cgraph_edges (ctxt_); }
 534   unsigned int execute () { return rebuild_cgraph_edges (); }
 535
 536 }; // class pass_rebuild_cgraph_edges
 537
 538 } // anon namespace
 539
 540 gimple_opt_pass *
 541 make_pass_rebuild_cgraph_edges (gcc::context *ctxt)
 542 {
 543   return new pass_rebuild_cgraph_edges (ctxt);
 544 }
 545
 546
 547 static unsigned int
 548 remove_cgraph_callee_edges (void)
 549 {
 550   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 551   cgraph_node_remove_callees (node);
 552   ipa_remove_all_references (&node->symbol.ref_list);
 553   return 0;
 554 }
 555
 556 namespace {
 557
 558 const pass_data pass_data_remove_cgraph_callee_edges =
 559 {
 560   GIMPLE_PASS, /* type */
 561   "*remove_cgraph_callee_edges", /* name */
 562   OPTGROUP_NONE, /* optinfo_flags */
 563   false, /* has_gate */
 564   true, /* has_execute */
 565   TV_NONE, /* tv_id */
 566   0, /* properties_required */
 567   0, /* properties_provided */
 568   0, /* properties_destroyed */
 569   0, /* todo_flags_start */
 570   0, /* todo_flags_finish */
 571 };
 572
 573 class pass_remove_cgraph_callee_edges : public gimple_opt_pass
 574 {
 575 public:
 576   pass_remove_cgraph_callee_edges(gcc::context *ctxt)
 577     : gimple_opt_pass(pass_data_remove_cgraph_callee_edges, ctxt)
 578   {}
 579
 580   /* opt_pass methods: */
 581   opt_pass * clone () {
 582     return new pass_remove_cgraph_callee_edges (ctxt_);
 583   }
 584   unsigned int execute () { return remove_cgraph_callee_edges (); }
 585
 586 }; // class pass_remove_cgraph_callee_edges
 587
 588 } // anon namespace
 589
 590 gimple_opt_pass *
 591 make_pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 592 {
 593   return new pass_remove_cgraph_callee_edges (ctxt);
 594 }