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_node::get_create (decl);
  83           if (!ctx->only_vars)
  84             node->mark_address_taken ();
  85           ctx->varpool_node->add_reference (node, IPA_REF_ADDR);
  86         }
  87
  88       if (TREE_CODE (decl) == VAR_DECL)
  89         {
  90           varpool_node *vnode = varpool_node_for_decl (decl);
  91           ctx->varpool_node->add_reference (vnode, IPA_REF_ADDR);
  92         }
  93       *walk_subtrees = 0;
  94       break;
  95
  96     default:
  97       /* Save some cycles by not walking types and declaration as we
  98          won't find anything useful there anyway.  */
  99       if (IS_TYPE_OR_DECL_P (*tp))
 100         {
 101           *walk_subtrees = 0;
 102           break;
 103         }
 104       break;
 105     }
 106
 107   return NULL_TREE;
 108 }
 109
 110 /* Record references to typeinfos in the type list LIST.  */
 111
 112 static void
 113 record_type_list (struct cgraph_node *node, tree list)
 114 {
 115   for (; list; list = TREE_CHAIN (list))
 116     {
 117       tree type = TREE_VALUE (list);
 118
 119       if (TYPE_P (type))
 120         type = lookup_type_for_runtime (type);
 121       STRIP_NOPS (type);
 122       if (TREE_CODE (type) == ADDR_EXPR)
 123         {
 124           type = TREE_OPERAND (type, 0);
 125           if (TREE_CODE (type) == VAR_DECL)
 126             {
 127               varpool_node *vnode = varpool_node_for_decl (type);
 128               node->add_reference (vnode, IPA_REF_ADDR);
 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->decl))
 143     {
 144       tree per_decl = DECL_FUNCTION_PERSONALITY (node->decl);
 145       struct cgraph_node *per_node = cgraph_node::get_create (per_decl);
 146
 147       node->add_reference (per_node, IPA_REF_ADDR);
 148       per_node->mark_address_taken ();
 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_FN
 202                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 203   int freq = bb->frequency;
 204
 205   if (profile_status_for_fn (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, tree, void *data)
 222 {
 223   addr = get_base_address (addr);
 224   if (TREE_CODE (addr) == FUNCTION_DECL)
 225     {
 226       struct cgraph_node *node = cgraph_node::get_create (addr);
 227       node->mark_address_taken ();
 228       ((symtab_node *)data)->add_reference (node, IPA_REF_ADDR, stmt);
 229     }
 230   else if (addr && TREE_CODE (addr) == VAR_DECL
 231            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 232     {
 233       varpool_node *vnode = varpool_node_for_decl (addr);
 234
 235       ((symtab_node *)data)->add_reference (vnode, IPA_REF_ADDR, stmt);
 236     }
 237
 238   return false;
 239 }
 240
 241 /* Mark load of T.  */
 242
 243 static bool
 244 mark_load (gimple stmt, tree t, tree, void *data)
 245 {
 246   t = get_base_address (t);
 247   if (t && TREE_CODE (t) == FUNCTION_DECL)
 248     {
 249       /* ??? This can happen on platforms with descriptors when these are
 250          directly manipulated in the code.  Pretend that it's an address.  */
 251       struct cgraph_node *node = cgraph_node::get_create (t);
 252       node->mark_address_taken ();
 253       ((symtab_node *)data)->add_reference (node, IPA_REF_ADDR, stmt);
 254     }
 255   else if (t && TREE_CODE (t) == VAR_DECL
 256            && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 257     {
 258       varpool_node *vnode = varpool_node_for_decl (t);
 259
 260       ((symtab_node *)data)->add_reference (vnode, IPA_REF_LOAD, stmt);
 261     }
 262   return false;
 263 }
 264
 265 /* Mark store of T.  */
 266
 267 static bool
 268 mark_store (gimple stmt, tree t, tree, void *data)
 269 {
 270   t = get_base_address (t);
 271   if (t && TREE_CODE (t) == VAR_DECL
 272       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 273     {
 274       varpool_node *vnode = varpool_node_for_decl (t);
 275
 276       ((symtab_node *)data)->add_reference (vnode, IPA_REF_STORE, stmt);
 277      }
 278   return false;
 279 }
 280
 281 /* Record all references from cgraph_node that are taken in statement STMT.  */
 282
 283 void
 284 cgraph_node::record_stmt_references (gimple stmt)
 285 {
 286   walk_stmt_load_store_addr_ops (stmt, this, mark_load, mark_store,
 287                                  mark_address);
 288 }
 289
 290 /* Create cgraph edges for function calls.
 291    Also look for functions and variables having addresses taken.  */
 292
 293 namespace {
 294
 295 const pass_data pass_data_build_cgraph_edges =
 296 {
 297   GIMPLE_PASS, /* type */
 298   "*build_cgraph_edges", /* name */
 299   OPTGROUP_NONE, /* optinfo_flags */
 300   TV_NONE, /* tv_id */
 301   PROP_cfg, /* properties_required */
 302   0, /* properties_provided */
 303   0, /* properties_destroyed */
 304   0, /* todo_flags_start */
 305   0, /* todo_flags_finish */
 306 };
 307
 308 class pass_build_cgraph_edges : public gimple_opt_pass
 309 {
 310 public:
 311   pass_build_cgraph_edges (gcc::context *ctxt)
 312     : gimple_opt_pass (pass_data_build_cgraph_edges, ctxt)
 313   {}
 314
 315   /* opt_pass methods: */
 316   virtual unsigned int execute (function *);
 317
 318 }; // class pass_build_cgraph_edges
 319
 320 unsigned int
 321 pass_build_cgraph_edges::execute (function *fun)
 322 {
 323   basic_block bb;
 324   struct cgraph_node *node = cgraph_node::get (current_function_decl);
 325   struct pointer_set_t *visited_nodes = pointer_set_create ();
 326   gimple_stmt_iterator gsi;
 327   tree decl;
 328   unsigned ix;
 329
 330   /* Create the callgraph edges and record the nodes referenced by the function.
 331      body.  */
 332   FOR_EACH_BB_FN (bb, fun)
 333     {
 334       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 335         {
 336           gimple stmt = gsi_stmt (gsi);
 337           tree decl;
 338
 339           if (is_gimple_debug (stmt))
 340             continue;
 341
 342           if (is_gimple_call (stmt))
 343             {
 344               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 345                                                          bb);
 346               decl = gimple_call_fndecl (stmt);
 347               if (decl)
 348                 node->create_edge (cgraph_node::get_create (decl),
 349                                    stmt, bb->count, freq);
 350               else if (gimple_call_internal_p (stmt))
 351                 ;
 352               else
 353                 node->create_indirect_edge (stmt,
 354                                             gimple_call_flags (stmt),
 355                                             bb->count, freq);
 356             }
 357           node->record_stmt_references (stmt);
 358           if (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
 359               && gimple_omp_parallel_child_fn (stmt))
 360             {
 361               tree fn = gimple_omp_parallel_child_fn (stmt);
 362               node->add_reference (cgraph_node::get_create (fn),
 363                                       IPA_REF_ADDR, stmt);
 364             }
 365           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 366             {
 367               tree fn = gimple_omp_task_child_fn (stmt);
 368               if (fn)
 369                 node->add_reference (cgraph_node::get_create (fn),
 370                                         IPA_REF_ADDR, stmt);
 371               fn = gimple_omp_task_copy_fn (stmt);
 372               if (fn)
 373                 node->add_reference (cgraph_node::get_create (fn),
 374                                         IPA_REF_ADDR, stmt);
 375             }
 376         }
 377       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 378         node->record_stmt_references (gsi_stmt (gsi));
 379    }
 380
 381   /* Look for initializers of constant variables and private statics.  */
 382   FOR_EACH_LOCAL_DECL (fun, ix, decl)
 383     if (TREE_CODE (decl) == VAR_DECL
 384         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
 385         && !DECL_HAS_VALUE_EXPR_P (decl))
 386       varpool_finalize_decl (decl);
 387   record_eh_tables (node, fun);
 388
 389   pointer_set_destroy (visited_nodes);
 390   return 0;
 391 }
 392
 393 } // anon namespace
 394
 395 gimple_opt_pass *
 396 make_pass_build_cgraph_edges (gcc::context *ctxt)
 397 {
 398   return new pass_build_cgraph_edges (ctxt);
 399 }
 400
 401 /* Record references to functions and other variables present in the
 402    initial value of DECL, a variable.
 403    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 404
 405 void
 406 record_references_in_initializer (tree decl, bool only_vars)
 407 {
 408   struct pointer_set_t *visited_nodes = pointer_set_create ();
 409   varpool_node *node = varpool_node_for_decl (decl);
 410   struct record_reference_ctx ctx = {false, NULL};
 411
 412   ctx.varpool_node = node;
 413   ctx.only_vars = only_vars;
 414   walk_tree (&DECL_INITIAL (decl), record_reference,
 415              &ctx, visited_nodes);
 416   pointer_set_destroy (visited_nodes);
 417 }
 418
 419 /* Rebuild cgraph edges for current function node.  This needs to be run after
 420    passes that don't update the cgraph.  */
 421
 422 unsigned int
 423 rebuild_cgraph_edges (void)
 424 {
 425   basic_block bb;
 426   struct cgraph_node *node = cgraph_node::get (current_function_decl);
 427   gimple_stmt_iterator gsi;
 428
 429   node->remove_callees ();
 430   node->remove_all_references ();
 431
 432   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 433
 434   FOR_EACH_BB_FN (bb, cfun)
 435     {
 436       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 437         {
 438           gimple stmt = gsi_stmt (gsi);
 439           tree decl;
 440
 441           if (is_gimple_call (stmt))
 442             {
 443               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 444                                                          bb);
 445               decl = gimple_call_fndecl (stmt);
 446               if (decl)
 447                 node->create_edge (cgraph_node::get_create (decl), stmt,
 448                                    bb->count, freq);
 449               else if (gimple_call_internal_p (stmt))
 450                 ;
 451               else
 452                 node->create_indirect_edge (stmt,
 453                                             gimple_call_flags (stmt),
 454                                             bb->count, freq);
 455             }
 456           node->record_stmt_references (stmt);
 457         }
 458       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 459         node->record_stmt_references (gsi_stmt (gsi));
 460     }
 461   record_eh_tables (node, cfun);
 462   gcc_assert (!node->global.inlined_to);
 463
 464   return 0;
 465 }
 466
 467 /* Rebuild cgraph edges for current function node.  This needs to be run after
 468    passes that don't update the cgraph.  */
 469
 470 void
 471 cgraph_rebuild_references (void)
 472 {
 473   basic_block bb;
 474   struct cgraph_node *node = cgraph_node::get (current_function_decl);
 475   gimple_stmt_iterator gsi;
 476   struct ipa_ref *ref = NULL;
 477   int i;
 478
 479   /* Keep speculative references for further cgraph edge expansion.  */
 480   for (i = 0; node->iterate_reference (i, ref);)
 481     if (!ref->speculative)
 482       ref->remove_reference ();
 483     else
 484       i++;
 485
 486   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 487
 488   FOR_EACH_BB_FN (bb, cfun)
 489     {
 490       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 491         node->record_stmt_references (gsi_stmt (gsi));
 492       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 493         node->record_stmt_references (gsi_stmt (gsi));
 494     }
 495   record_eh_tables (node, cfun);
 496 }
 497
 498 namespace {
 499
 500 const pass_data pass_data_rebuild_cgraph_edges =
 501 {
 502   GIMPLE_PASS, /* type */
 503   "*rebuild_cgraph_edges", /* name */
 504   OPTGROUP_NONE, /* optinfo_flags */
 505   TV_CGRAPH, /* tv_id */
 506   PROP_cfg, /* properties_required */
 507   0, /* properties_provided */
 508   0, /* properties_destroyed */
 509   0, /* todo_flags_start */
 510   0, /* todo_flags_finish */
 511 };
 512
 513 class pass_rebuild_cgraph_edges : public gimple_opt_pass
 514 {
 515 public:
 516   pass_rebuild_cgraph_edges (gcc::context *ctxt)
 517     : gimple_opt_pass (pass_data_rebuild_cgraph_edges, ctxt)
 518   {}
 519
 520   /* opt_pass methods: */
 521   opt_pass * clone () { return new pass_rebuild_cgraph_edges (m_ctxt); }
 522   virtual unsigned int execute (function *) { return rebuild_cgraph_edges (); }
 523
 524 }; // class pass_rebuild_cgraph_edges
 525
 526 } // anon namespace
 527
 528 gimple_opt_pass *
 529 make_pass_rebuild_cgraph_edges (gcc::context *ctxt)
 530 {
 531   return new pass_rebuild_cgraph_edges (ctxt);
 532 }
 533
 534
 535 namespace {
 536
 537 const pass_data pass_data_remove_cgraph_callee_edges =
 538 {
 539   GIMPLE_PASS, /* type */
 540   "*remove_cgraph_callee_edges", /* name */
 541   OPTGROUP_NONE, /* optinfo_flags */
 542   TV_NONE, /* tv_id */
 543   0, /* properties_required */
 544   0, /* properties_provided */
 545   0, /* properties_destroyed */
 546   0, /* todo_flags_start */
 547   0, /* todo_flags_finish */
 548 };
 549
 550 class pass_remove_cgraph_callee_edges : public gimple_opt_pass
 551 {
 552 public:
 553   pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 554     : gimple_opt_pass (pass_data_remove_cgraph_callee_edges, ctxt)
 555   {}
 556
 557   /* opt_pass methods: */
 558   opt_pass * clone () {
 559     return new pass_remove_cgraph_callee_edges (m_ctxt);
 560   }
 561   virtual unsigned int execute (function *);
 562
 563 }; // class pass_remove_cgraph_callee_edges
 564
 565 unsigned int
 566 pass_remove_cgraph_callee_edges::execute (function *)
 567 {
 568   struct cgraph_node *node = cgraph_node::get (current_function_decl);
 569   node->remove_callees ();
 570   node->remove_all_references ();
 571   return 0;
 572 }
 573
 574 } // anon namespace
 575
 576 gimple_opt_pass *
 577 make_pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 578 {
 579   return new pass_remove_cgraph_callee_edges (ctxt);
 580 }