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