gcc/cgraphbuild.c

   1 /* Callgraph construction.
   2    Copyright (C) 2003-2017 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 "backend.h"
  25 #include "tree.h"
  26 #include "gimple.h"
  27 #include "tree-pass.h"
  28 #include "cgraph.h"
  29 #include "gimple-fold.h"
  30 #include "gimple-iterator.h"
  31 #include "gimple-walk.h"
  32 #include "ipa-utils.h"
  33 #include "except.h"
  34
  35 /* Context of record_reference.  */
  36 struct record_reference_ctx
  37 {
  38   bool only_vars;
  39   class 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   record_reference_ctx *ctx = (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           cgraph_node *node = cgraph_node::get_create (decl);
  75           if (!ctx->only_vars)
  76             node->mark_address_taken ();
  77           ctx->varpool_node->create_reference (node, IPA_REF_ADDR);
  78         }
  79
  80       if (VAR_P (decl))
  81         {
  82           varpool_node *vnode = varpool_node::get_create (decl);
  83           ctx->varpool_node->create_reference (vnode, IPA_REF_ADDR);
  84         }
  85       *walk_subtrees = 0;
  86       break;
  87
  88     default:
  89       /* Save some cycles by not walking types and declaration as we
  90          won't find anything useful there anyway.  */
  91       if (IS_TYPE_OR_DECL_P (*tp))
  92         {
  93           *walk_subtrees = 0;
  94           break;
  95         }
  96       break;
  97     }
  98
  99   return NULL_TREE;
 100 }
 101
 102 /* Record references to typeinfos in the type list LIST.  */
 103
 104 static void
 105 record_type_list (cgraph_node *node, tree list)
 106 {
 107   for (; list; list = TREE_CHAIN (list))
 108     {
 109       tree type = TREE_VALUE (list);
 110
 111       if (TYPE_P (type))
 112         type = lookup_type_for_runtime (type);
 113       STRIP_NOPS (type);
 114       if (TREE_CODE (type) == ADDR_EXPR)
 115         {
 116           type = TREE_OPERAND (type, 0);
 117           if (VAR_P (type))
 118             {
 119               varpool_node *vnode = varpool_node::get_create (type);
 120               node->create_reference (vnode, IPA_REF_ADDR);
 121             }
 122         }
 123     }
 124 }
 125
 126 /* Record all references we will introduce by producing EH tables
 127    for NODE.  */
 128
 129 static void
 130 record_eh_tables (cgraph_node *node, function *fun)
 131 {
 132   eh_region i;
 133
 134   if (DECL_FUNCTION_PERSONALITY (node->decl))
 135     {
 136       tree per_decl = DECL_FUNCTION_PERSONALITY (node->decl);
 137       cgraph_node *per_node = cgraph_node::get_create (per_decl);
 138
 139       node->create_reference (per_node, IPA_REF_ADDR);
 140       per_node->mark_address_taken ();
 141     }
 142
 143   i = fun->eh->region_tree;
 144   if (!i)
 145     return;
 146
 147   while (1)
 148     {
 149       switch (i->type)
 150         {
 151         case ERT_CLEANUP:
 152         case ERT_MUST_NOT_THROW:
 153           break;
 154
 155         case ERT_TRY:
 156           {
 157             eh_catch c;
 158             for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
 159               record_type_list (node, c->type_list);
 160           }
 161           break;
 162
 163         case ERT_ALLOWED_EXCEPTIONS:
 164           record_type_list (node, i->u.allowed.type_list);
 165           break;
 166         }
 167       /* If there are sub-regions, process them.  */
 168       if (i->inner)
 169         i = i->inner;
 170       /* If there are peers, process them.  */
 171       else if (i->next_peer)
 172         i = i->next_peer;
 173       /* Otherwise, step back up the tree to the next peer.  */
 174       else
 175         {
 176           do
 177             {
 178               i = i->outer;
 179               if (i == NULL)
 180                 return;
 181             }
 182           while (i->next_peer == NULL);
 183           i = i->next_peer;
 184         }
 185     }
 186 }
 187
 188 /* Computes the frequency of the call statement so that it can be stored in
 189    cgraph_edge.  BB is the basic block of the call statement.  */
 190 int
 191 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 192 {
 193   int entry_freq = ENTRY_BLOCK_PTR_FOR_FN
 194                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 195   int freq = bb->frequency;
 196
 197   if (profile_status_for_fn (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 198     return CGRAPH_FREQ_BASE;
 199
 200   if (!entry_freq)
 201     entry_freq = 1, freq++;
 202
 203   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 204   if (freq > CGRAPH_FREQ_MAX)
 205     freq = CGRAPH_FREQ_MAX;
 206
 207   return freq;
 208 }
 209
 210 /* Mark address taken in STMT.  */
 211
 212 static bool
 213 mark_address (gimple *stmt, tree addr, tree, void *data)
 214 {
 215   addr = get_base_address (addr);
 216   if (TREE_CODE (addr) == FUNCTION_DECL)
 217     {
 218       cgraph_node *node = cgraph_node::get_create (addr);
 219       node->mark_address_taken ();
 220       ((symtab_node *)data)->create_reference (node, IPA_REF_ADDR, stmt);
 221     }
 222   else if (addr && VAR_P (addr)
 223            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 224     {
 225       varpool_node *vnode = varpool_node::get_create (addr);
 226
 227       ((symtab_node *)data)->create_reference (vnode, IPA_REF_ADDR, stmt);
 228     }
 229
 230   return false;
 231 }
 232
 233 /* Mark load of T.  */
 234
 235 static bool
 236 mark_load (gimple *stmt, tree t, tree, void *data)
 237 {
 238   t = get_base_address (t);
 239   if (t && TREE_CODE (t) == FUNCTION_DECL)
 240     {
 241       /* ??? This can happen on platforms with descriptors when these are
 242          directly manipulated in the code.  Pretend that it's an address.  */
 243       cgraph_node *node = cgraph_node::get_create (t);
 244       node->mark_address_taken ();
 245       ((symtab_node *)data)->create_reference (node, IPA_REF_ADDR, stmt);
 246     }
 247   else if (t && VAR_P (t) && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 248     {
 249       varpool_node *vnode = varpool_node::get_create (t);
 250
 251       ((symtab_node *)data)->create_reference (vnode, IPA_REF_LOAD, stmt);
 252     }
 253   return false;
 254 }
 255
 256 /* Mark store of T.  */
 257
 258 static bool
 259 mark_store (gimple *stmt, tree t, tree, void *data)
 260 {
 261   t = get_base_address (t);
 262   if (t && VAR_P (t) && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 263     {
 264       varpool_node *vnode = varpool_node::get_create (t);
 265
 266       ((symtab_node *)data)->create_reference (vnode, IPA_REF_STORE, stmt);
 267      }
 268   return false;
 269 }
 270
 271 /* Record all references from cgraph_node that are taken in statement STMT.  */
 272
 273 void
 274 cgraph_node::record_stmt_references (gimple *stmt)
 275 {
 276   walk_stmt_load_store_addr_ops (stmt, this, mark_load, mark_store,
 277                                  mark_address);
 278 }
 279
 280 /* Create cgraph edges for function calls.
 281    Also look for functions and variables having addresses taken.  */
 282
 283 namespace {
 284
 285 const pass_data pass_data_build_cgraph_edges =
 286 {
 287   GIMPLE_PASS, /* type */
 288   "*build_cgraph_edges", /* name */
 289   OPTGROUP_NONE, /* optinfo_flags */
 290   TV_NONE, /* tv_id */
 291   PROP_cfg, /* properties_required */
 292   0, /* properties_provided */
 293   0, /* properties_destroyed */
 294   0, /* todo_flags_start */
 295   0, /* todo_flags_finish */
 296 };
 297
 298 class pass_build_cgraph_edges : public gimple_opt_pass
 299 {
 300 public:
 301   pass_build_cgraph_edges (gcc::context *ctxt)
 302     : gimple_opt_pass (pass_data_build_cgraph_edges, ctxt)
 303   {}
 304
 305   /* opt_pass methods: */
 306   virtual unsigned int execute (function *);
 307
 308 }; // class pass_build_cgraph_edges
 309
 310 unsigned int
 311 pass_build_cgraph_edges::execute (function *fun)
 312 {
 313   basic_block bb;
 314   cgraph_node *node = cgraph_node::get (current_function_decl);
 315   gimple_stmt_iterator gsi;
 316   tree decl;
 317   unsigned ix;
 318
 319   /* Create the callgraph edges and record the nodes referenced by the function.
 320      body.  */
 321   FOR_EACH_BB_FN (bb, fun)
 322     {
 323       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 324         {
 325           gimple *stmt = gsi_stmt (gsi);
 326           tree decl;
 327
 328           if (is_gimple_debug (stmt))
 329             continue;
 330
 331           if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 332             {
 333               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 334                                                          bb);
 335               decl = gimple_call_fndecl (call_stmt);
 336               if (decl)
 337                 node->create_edge (cgraph_node::get_create (decl), call_stmt, bb->count, freq);
 338               else if (gimple_call_internal_p (call_stmt))
 339                 ;
 340               else
 341                 node->create_indirect_edge (call_stmt,
 342                                             gimple_call_flags (call_stmt),
 343                                             bb->count, freq);
 344             }
 345           node->record_stmt_references (stmt);
 346           if (gomp_parallel *omp_par_stmt = dyn_cast <gomp_parallel *> (stmt))
 347             {
 348               tree fn = gimple_omp_parallel_child_fn (omp_par_stmt);
 349               node->create_reference (cgraph_node::get_create (fn),
 350                                       IPA_REF_ADDR, stmt);
 351             }
 352           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 353             {
 354               tree fn = gimple_omp_task_child_fn (stmt);
 355               if (fn)
 356                 node->create_reference (cgraph_node::get_create (fn),
 357                                         IPA_REF_ADDR, stmt);
 358               fn = gimple_omp_task_copy_fn (stmt);
 359               if (fn)
 360                 node->create_reference (cgraph_node::get_create (fn),
 361                                         IPA_REF_ADDR, stmt);
 362             }
 363         }
 364       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 365         node->record_stmt_references (gsi_stmt (gsi));
 366    }
 367
 368   /* Look for initializers of constant variables and private statics.  */
 369   FOR_EACH_LOCAL_DECL (fun, ix, decl)
 370     if (VAR_P (decl)
 371         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
 372         && !DECL_HAS_VALUE_EXPR_P (decl)
 373         && TREE_TYPE (decl) != error_mark_node)
 374       varpool_node::finalize_decl (decl);
 375   record_eh_tables (node, fun);
 376
 377   return 0;
 378 }
 379
 380 } // anon namespace
 381
 382 gimple_opt_pass *
 383 make_pass_build_cgraph_edges (gcc::context *ctxt)
 384 {
 385   return new pass_build_cgraph_edges (ctxt);
 386 }
 387
 388 /* Record references to functions and other variables present in the
 389    initial value of DECL, a variable.
 390    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 391
 392 void
 393 record_references_in_initializer (tree decl, bool only_vars)
 394 {
 395   varpool_node *node = varpool_node::get_create (decl);
 396   hash_set<tree> visited_nodes;
 397   record_reference_ctx ctx = {false, NULL};
 398
 399   ctx.varpool_node = node;
 400   ctx.only_vars = only_vars;
 401   walk_tree (&DECL_INITIAL (decl), record_reference,
 402              &ctx, &visited_nodes);
 403 }
 404
 405 /* Rebuild cgraph edges for current function node.  This needs to be run after
 406    passes that don't update the cgraph.  */
 407
 408 unsigned int
 409 cgraph_edge::rebuild_edges (void)
 410 {
 411   basic_block bb;
 412   cgraph_node *node = cgraph_node::get (current_function_decl);
 413   gimple_stmt_iterator gsi;
 414
 415   node->remove_callees ();
 416   node->remove_all_references ();
 417
 418   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 419
 420   FOR_EACH_BB_FN (bb, cfun)
 421     {
 422       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 423         {
 424           gimple *stmt = gsi_stmt (gsi);
 425           tree decl;
 426
 427           if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 428             {
 429               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 430                                                          bb);
 431               decl = gimple_call_fndecl (call_stmt);
 432               if (decl)
 433                 node->create_edge (cgraph_node::get_create (decl), call_stmt,
 434                                    bb->count, freq);
 435               else if (gimple_call_internal_p (call_stmt))
 436                 ;
 437               else
 438                 node->create_indirect_edge (call_stmt,
 439                                             gimple_call_flags (call_stmt),
 440                                             bb->count, freq);
 441             }
 442           node->record_stmt_references (stmt);
 443         }
 444       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 445         node->record_stmt_references (gsi_stmt (gsi));
 446     }
 447   record_eh_tables (node, cfun);
 448   gcc_assert (!node->global.inlined_to);
 449
 450   if (node->instrumented_version
 451       && !node->instrumentation_clone)
 452     node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
 453
 454   return 0;
 455 }
 456
 457 /* Rebuild cgraph references for current function node.  This needs to be run
 458    after passes that don't update the cgraph.  */
 459
 460 void
 461 cgraph_edge::rebuild_references (void)
 462 {
 463   basic_block bb;
 464   cgraph_node *node = cgraph_node::get (current_function_decl);
 465   gimple_stmt_iterator gsi;
 466   ipa_ref *ref = NULL;
 467   int i;
 468
 469   /* Keep speculative references for further cgraph edge expansion.  */
 470   for (i = 0; node->iterate_reference (i, ref);)
 471     if (!ref->speculative)
 472       ref->remove_reference ();
 473     else
 474       i++;
 475
 476   FOR_EACH_BB_FN (bb, cfun)
 477     {
 478       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 479         node->record_stmt_references (gsi_stmt (gsi));
 480       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 481         node->record_stmt_references (gsi_stmt (gsi));
 482     }
 483   record_eh_tables (node, cfun);
 484
 485   if (node->instrumented_version
 486       && !node->instrumentation_clone)
 487     node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
 488 }
 489
 490 namespace {
 491
 492 const pass_data pass_data_rebuild_cgraph_edges =
 493 {
 494   GIMPLE_PASS, /* type */
 495   "*rebuild_cgraph_edges", /* name */
 496   OPTGROUP_NONE, /* optinfo_flags */
 497   TV_CGRAPH, /* tv_id */
 498   PROP_cfg, /* properties_required */
 499   0, /* properties_provided */
 500   0, /* properties_destroyed */
 501   0, /* todo_flags_start */
 502   0, /* todo_flags_finish */
 503 };
 504
 505 class pass_rebuild_cgraph_edges : public gimple_opt_pass
 506 {
 507 public:
 508   pass_rebuild_cgraph_edges (gcc::context *ctxt)
 509     : gimple_opt_pass (pass_data_rebuild_cgraph_edges, ctxt)
 510   {}
 511
 512   /* opt_pass methods: */
 513   opt_pass * clone () { return new pass_rebuild_cgraph_edges (m_ctxt); }
 514   virtual unsigned int execute (function *)
 515   {
 516     return cgraph_edge::rebuild_edges ();
 517   }
 518
 519 }; // class pass_rebuild_cgraph_edges
 520
 521 } // anon namespace
 522
 523 gimple_opt_pass *
 524 make_pass_rebuild_cgraph_edges (gcc::context *ctxt)
 525 {
 526   return new pass_rebuild_cgraph_edges (ctxt);
 527 }
 528
 529
 530 namespace {
 531
 532 const pass_data pass_data_remove_cgraph_callee_edges =
 533 {
 534   GIMPLE_PASS, /* type */
 535   "*remove_cgraph_callee_edges", /* name */
 536   OPTGROUP_NONE, /* optinfo_flags */
 537   TV_NONE, /* tv_id */
 538   0, /* properties_required */
 539   0, /* properties_provided */
 540   0, /* properties_destroyed */
 541   0, /* todo_flags_start */
 542   0, /* todo_flags_finish */
 543 };
 544
 545 class pass_remove_cgraph_callee_edges : public gimple_opt_pass
 546 {
 547 public:
 548   pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 549     : gimple_opt_pass (pass_data_remove_cgraph_callee_edges, ctxt)
 550   {}
 551
 552   /* opt_pass methods: */
 553   opt_pass * clone () {
 554     return new pass_remove_cgraph_callee_edges (m_ctxt);
 555   }
 556   virtual unsigned int execute (function *);
 557
 558 }; // class pass_remove_cgraph_callee_edges
 559
 560 unsigned int
 561 pass_remove_cgraph_callee_edges::execute (function *)
 562 {
 563   cgraph_node *node = cgraph_node::get (current_function_decl);
 564   node->remove_callees ();
 565   node->remove_all_references ();
 566   return 0;
 567 }
 568
 569 } // anon namespace
 570
 571 gimple_opt_pass *
 572 make_pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 573 {
 574   return new pass_remove_cgraph_callee_edges (ctxt);
 575 }