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