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_get_create_node (decl);
  83           if (!ctx->only_vars)
  84             cgraph_mark_address_taken_node (node);
  85           ipa_record_reference (ctx->varpool_node,
  86                                 node,
  87                                 IPA_REF_ADDR, NULL);
  88         }
  89
  90       if (TREE_CODE (decl) == VAR_DECL)
  91         {
  92           varpool_node *vnode = varpool_node_for_decl (decl);
  93           ipa_record_reference (ctx->varpool_node,
  94                                 vnode,
  95                                 IPA_REF_ADDR, NULL);
  96         }
  97       *walk_subtrees = 0;
  98       break;
  99
 100     default:
 101       /* Save some cycles by not walking types and declaration as we
 102          won't find anything useful there anyway.  */
 103       if (IS_TYPE_OR_DECL_P (*tp))
 104         {
 105           *walk_subtrees = 0;
 106           break;
 107         }
 108       break;
 109     }
 110
 111   return NULL_TREE;
 112 }
 113
 114 /* Record references to typeinfos in the type list LIST.  */
 115
 116 static void
 117 record_type_list (struct cgraph_node *node, tree list)
 118 {
 119   for (; list; list = TREE_CHAIN (list))
 120     {
 121       tree type = TREE_VALUE (list);
 122
 123       if (TYPE_P (type))
 124         type = lookup_type_for_runtime (type);
 125       STRIP_NOPS (type);
 126       if (TREE_CODE (type) == ADDR_EXPR)
 127         {
 128           type = TREE_OPERAND (type, 0);
 129           if (TREE_CODE (type) == VAR_DECL)
 130             {
 131               varpool_node *vnode = varpool_node_for_decl (type);
 132               ipa_record_reference (node,
 133                                     vnode,
 134                                     IPA_REF_ADDR, NULL);
 135             }
 136         }
 137     }
 138 }
 139
 140 /* Record all references we will introduce by producing EH tables
 141    for NODE.  */
 142
 143 static void
 144 record_eh_tables (struct cgraph_node *node, struct function *fun)
 145 {
 146   eh_region i;
 147
 148   if (DECL_FUNCTION_PERSONALITY (node->decl))
 149     {
 150       tree per_decl = DECL_FUNCTION_PERSONALITY (node->decl);
 151       struct cgraph_node *per_node = cgraph_get_create_node (per_decl);
 152
 153       ipa_record_reference (node, per_node, IPA_REF_ADDR, NULL);
 154       cgraph_mark_address_taken_node (per_node);
 155     }
 156
 157   i = fun->eh->region_tree;
 158   if (!i)
 159     return;
 160
 161   while (1)
 162     {
 163       switch (i->type)
 164         {
 165         case ERT_CLEANUP:
 166         case ERT_MUST_NOT_THROW:
 167           break;
 168
 169         case ERT_TRY:
 170           {
 171             eh_catch c;
 172             for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
 173               record_type_list (node, c->type_list);
 174           }
 175           break;
 176
 177         case ERT_ALLOWED_EXCEPTIONS:
 178           record_type_list (node, i->u.allowed.type_list);
 179           break;
 180         }
 181       /* If there are sub-regions, process them.  */
 182       if (i->inner)
 183         i = i->inner;
 184       /* If there are peers, process them.  */
 185       else if (i->next_peer)
 186         i = i->next_peer;
 187       /* Otherwise, step back up the tree to the next peer.  */
 188       else
 189         {
 190           do
 191             {
 192               i = i->outer;
 193               if (i == NULL)
 194                 return;
 195             }
 196           while (i->next_peer == NULL);
 197           i = i->next_peer;
 198         }
 199     }
 200 }
 201
 202 /* Computes the frequency of the call statement so that it can be stored in
 203    cgraph_edge.  BB is the basic block of the call statement.  */
 204 int
 205 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 206 {
 207   int entry_freq = ENTRY_BLOCK_PTR_FOR_FN
 208                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 209   int freq = bb->frequency;
 210
 211   if (profile_status_for_fn (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 212     return CGRAPH_FREQ_BASE;
 213
 214   if (!entry_freq)
 215     entry_freq = 1, freq++;
 216
 217   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 218   if (freq > CGRAPH_FREQ_MAX)
 219     freq = CGRAPH_FREQ_MAX;
 220
 221   return freq;
 222 }
 223
 224 /* Mark address taken in STMT.  */
 225
 226 static bool
 227 mark_address (gimple stmt, tree addr, tree, void *data)
 228 {
 229   addr = get_base_address (addr);
 230   if (TREE_CODE (addr) == FUNCTION_DECL)
 231     {
 232       struct cgraph_node *node = cgraph_get_create_node (addr);
 233       cgraph_mark_address_taken_node (node);
 234       ipa_record_reference ((symtab_node *)data,
 235                             node,
 236                             IPA_REF_ADDR, stmt);
 237     }
 238   else if (addr && TREE_CODE (addr) == VAR_DECL
 239            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 240     {
 241       varpool_node *vnode = varpool_node_for_decl (addr);
 242
 243       ipa_record_reference ((symtab_node *)data,
 244                             vnode,
 245                             IPA_REF_ADDR, stmt);
 246     }
 247
 248   return false;
 249 }
 250
 251 /* Mark load of T.  */
 252
 253 static bool
 254 mark_load (gimple stmt, tree t, tree, void *data)
 255 {
 256   t = get_base_address (t);
 257   if (t && TREE_CODE (t) == FUNCTION_DECL)
 258     {
 259       /* ??? This can happen on platforms with descriptors when these are
 260          directly manipulated in the code.  Pretend that it's an address.  */
 261       struct cgraph_node *node = cgraph_get_create_node (t);
 262       cgraph_mark_address_taken_node (node);
 263       ipa_record_reference ((symtab_node *)data,
 264                             node,
 265                             IPA_REF_ADDR, stmt);
 266     }
 267   else if (t && TREE_CODE (t) == VAR_DECL
 268            && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 269     {
 270       varpool_node *vnode = varpool_node_for_decl (t);
 271
 272       ipa_record_reference ((symtab_node *)data,
 273                             vnode,
 274                             IPA_REF_LOAD, stmt);
 275     }
 276   return false;
 277 }
 278
 279 /* Mark store of T.  */
 280
 281 static bool
 282 mark_store (gimple stmt, tree t, tree, void *data)
 283 {
 284   t = get_base_address (t);
 285   if (t && TREE_CODE (t) == VAR_DECL
 286       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 287     {
 288       varpool_node *vnode = varpool_node_for_decl (t);
 289
 290       ipa_record_reference ((symtab_node *)data,
 291                             vnode,
 292                             IPA_REF_STORE, stmt);
 293      }
 294   return false;
 295 }
 296
 297 /* Record all references from NODE that are taken in statement STMT.  */
 298 void
 299 ipa_record_stmt_references (struct cgraph_node *node, gimple stmt)
 300 {
 301   walk_stmt_load_store_addr_ops (stmt, node, mark_load, mark_store,
 302                                  mark_address);
 303 }
 304
 305 /* Create cgraph edges for function calls.
 306    Also look for functions and variables having addresses taken.  */
 307
 308 static unsigned int
 309 build_cgraph_edges (void)
 310 {
 311   basic_block bb;
 312   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 313   struct pointer_set_t *visited_nodes = pointer_set_create ();
 314   gimple_stmt_iterator gsi;
 315   tree decl;
 316   unsigned ix;
 317
 318   /* Create the callgraph edges and record the nodes referenced by the function.
 319      body.  */
 320   FOR_EACH_BB_FN (bb, cfun)
 321     {
 322       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 323         {
 324           gimple stmt = gsi_stmt (gsi);
 325           tree decl;
 326
 327           if (is_gimple_debug (stmt))
 328             continue;
 329
 330           if (is_gimple_call (stmt))
 331             {
 332               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 333                                                          bb);
 334               decl = gimple_call_fndecl (stmt);
 335               if (decl)
 336                 cgraph_create_edge (node, cgraph_get_create_node (decl),
 337                                     stmt, bb->count, freq);
 338               else if (gimple_call_internal_p (stmt))
 339                 ;
 340               else
 341                 cgraph_create_indirect_edge (node, stmt,
 342                                              gimple_call_flags (stmt),
 343                                              bb->count, freq);
 344             }
 345           ipa_record_stmt_references (node, stmt);
 346           if (gimple_code (stmt) == GIMPLE_OACC_PARALLEL
 347               && gimple_oacc_parallel_child_fn (stmt))
 348             {
 349               tree fn = gimple_oacc_parallel_child_fn (stmt);
 350               ipa_record_reference (node,
 351                                     cgraph_get_create_node (fn),
 352                                     IPA_REF_ADDR, stmt);
 353             }
 354           else if (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
 355                    && gimple_omp_parallel_child_fn (stmt))
 356             {
 357               tree fn = gimple_omp_parallel_child_fn (stmt);
 358               ipa_record_reference (node,
 359                                     cgraph_get_create_node (fn),
 360                                     IPA_REF_ADDR, stmt);
 361             }
 362           else if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 363             {
 364               tree fn = gimple_omp_task_child_fn (stmt);
 365               if (fn)
 366                 ipa_record_reference (node,
 367                                       cgraph_get_create_node (fn),
 368                                       IPA_REF_ADDR, stmt);
 369               fn = gimple_omp_task_copy_fn (stmt);
 370               if (fn)
 371                 ipa_record_reference (node,
 372                                       cgraph_get_create_node (fn),
 373                                       IPA_REF_ADDR, stmt);
 374             }
 375         }
 376       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 377         ipa_record_stmt_references (node, gsi_stmt (gsi));
 378    }
 379
 380   /* Look for initializers of constant variables and private statics.  */
 381   FOR_EACH_LOCAL_DECL (cfun, ix, decl)
 382     if (TREE_CODE (decl) == VAR_DECL
 383         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
 384         && !DECL_HAS_VALUE_EXPR_P (decl))
 385       varpool_finalize_decl (decl);
 386   record_eh_tables (node, cfun);
 387
 388   pointer_set_destroy (visited_nodes);
 389   return 0;
 390 }
 391
 392 namespace {
 393
 394 const pass_data pass_data_build_cgraph_edges =
 395 {
 396   GIMPLE_PASS, /* type */
 397   "*build_cgraph_edges", /* name */
 398   OPTGROUP_NONE, /* optinfo_flags */
 399   false, /* has_gate */
 400   true, /* has_execute */
 401   TV_NONE, /* tv_id */
 402   PROP_cfg, /* properties_required */
 403   0, /* properties_provided */
 404   0, /* properties_destroyed */
 405   0, /* todo_flags_start */
 406   0, /* todo_flags_finish */
 407 };
 408
 409 class pass_build_cgraph_edges : public gimple_opt_pass
 410 {
 411 public:
 412   pass_build_cgraph_edges (gcc::context *ctxt)
 413     : gimple_opt_pass (pass_data_build_cgraph_edges, ctxt)
 414   {}
 415
 416   /* opt_pass methods: */
 417   unsigned int execute () { return build_cgraph_edges (); }
 418
 419 }; // class pass_build_cgraph_edges
 420
 421 } // anon namespace
 422
 423 gimple_opt_pass *
 424 make_pass_build_cgraph_edges (gcc::context *ctxt)
 425 {
 426   return new pass_build_cgraph_edges (ctxt);
 427 }
 428
 429 /* Record references to functions and other variables present in the
 430    initial value of DECL, a variable.
 431    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 432
 433 void
 434 record_references_in_initializer (tree decl, bool only_vars)
 435 {
 436   struct pointer_set_t *visited_nodes = pointer_set_create ();
 437   varpool_node *node = varpool_node_for_decl (decl);
 438   struct record_reference_ctx ctx = {false, NULL};
 439
 440   ctx.varpool_node = node;
 441   ctx.only_vars = only_vars;
 442   walk_tree (&DECL_INITIAL (decl), record_reference,
 443              &ctx, visited_nodes);
 444   pointer_set_destroy (visited_nodes);
 445 }
 446
 447 /* Rebuild cgraph edges for current function node.  This needs to be run after
 448    passes that don't update the cgraph.  */
 449
 450 unsigned int
 451 rebuild_cgraph_edges (void)
 452 {
 453   basic_block bb;
 454   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 455   gimple_stmt_iterator gsi;
 456
 457   cgraph_node_remove_callees (node);
 458   ipa_remove_all_references (&node->ref_list);
 459
 460   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 461
 462   FOR_EACH_BB_FN (bb, cfun)
 463     {
 464       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 465         {
 466           gimple stmt = gsi_stmt (gsi);
 467           tree decl;
 468
 469           if (is_gimple_call (stmt))
 470             {
 471               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 472                                                          bb);
 473               decl = gimple_call_fndecl (stmt);
 474               if (decl)
 475                 cgraph_create_edge (node, cgraph_get_create_node (decl), stmt,
 476                                     bb->count, freq);
 477               else if (gimple_call_internal_p (stmt))
 478                 ;
 479               else
 480                 cgraph_create_indirect_edge (node, stmt,
 481                                              gimple_call_flags (stmt),
 482                                              bb->count, freq);
 483             }
 484           ipa_record_stmt_references (node, stmt);
 485         }
 486       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 487         ipa_record_stmt_references (node, gsi_stmt (gsi));
 488     }
 489   record_eh_tables (node, cfun);
 490   gcc_assert (!node->global.inlined_to);
 491
 492   return 0;
 493 }
 494
 495 /* Rebuild cgraph edges for current function node.  This needs to be run after
 496    passes that don't update the cgraph.  */
 497
 498 void
 499 cgraph_rebuild_references (void)
 500 {
 501   basic_block bb;
 502   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 503   gimple_stmt_iterator gsi;
 504   struct ipa_ref *ref;
 505   int i;
 506
 507   /* Keep speculative references for further cgraph edge expansion.  */
 508   for (i = 0; ipa_ref_list_reference_iterate (&node->ref_list, i, ref);)
 509     if (!ref->speculative)
 510       ipa_remove_reference (ref);
 511     else
 512       i++;
 513
 514   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 515
 516   FOR_EACH_BB_FN (bb, cfun)
 517     {
 518       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 519         ipa_record_stmt_references (node, gsi_stmt (gsi));
 520       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 521         ipa_record_stmt_references (node, gsi_stmt (gsi));
 522     }
 523   record_eh_tables (node, cfun);
 524 }
 525
 526 namespace {
 527
 528 const pass_data pass_data_rebuild_cgraph_edges =
 529 {
 530   GIMPLE_PASS, /* type */
 531   "*rebuild_cgraph_edges", /* name */
 532   OPTGROUP_NONE, /* optinfo_flags */
 533   false, /* has_gate */
 534   true, /* has_execute */
 535   TV_CGRAPH, /* tv_id */
 536   PROP_cfg, /* properties_required */
 537   0, /* properties_provided */
 538   0, /* properties_destroyed */
 539   0, /* todo_flags_start */
 540   0, /* todo_flags_finish */
 541 };
 542
 543 class pass_rebuild_cgraph_edges : public gimple_opt_pass
 544 {
 545 public:
 546   pass_rebuild_cgraph_edges (gcc::context *ctxt)
 547     : gimple_opt_pass (pass_data_rebuild_cgraph_edges, ctxt)
 548   {}
 549
 550   /* opt_pass methods: */
 551   opt_pass * clone () { return new pass_rebuild_cgraph_edges (m_ctxt); }
 552   unsigned int execute () { return rebuild_cgraph_edges (); }
 553
 554 }; // class pass_rebuild_cgraph_edges
 555
 556 } // anon namespace
 557
 558 gimple_opt_pass *
 559 make_pass_rebuild_cgraph_edges (gcc::context *ctxt)
 560 {
 561   return new pass_rebuild_cgraph_edges (ctxt);
 562 }
 563
 564
 565 static unsigned int
 566 remove_cgraph_callee_edges (void)
 567 {
 568   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 569   cgraph_node_remove_callees (node);
 570   ipa_remove_all_references (&node->ref_list);
 571   return 0;
 572 }
 573
 574 namespace {
 575
 576 const pass_data pass_data_remove_cgraph_callee_edges =
 577 {
 578   GIMPLE_PASS, /* type */
 579   "*remove_cgraph_callee_edges", /* name */
 580   OPTGROUP_NONE, /* optinfo_flags */
 581   false, /* has_gate */
 582   true, /* has_execute */
 583   TV_NONE, /* tv_id */
 584   0, /* properties_required */
 585   0, /* properties_provided */
 586   0, /* properties_destroyed */
 587   0, /* todo_flags_start */
 588   0, /* todo_flags_finish */
 589 };
 590
 591 class pass_remove_cgraph_callee_edges : public gimple_opt_pass
 592 {
 593 public:
 594   pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 595     : gimple_opt_pass (pass_data_remove_cgraph_callee_edges, ctxt)
 596   {}
 597
 598   /* opt_pass methods: */
 599   opt_pass * clone () {
 600     return new pass_remove_cgraph_callee_edges (m_ctxt);
 601   }
 602   unsigned int execute () { return remove_cgraph_callee_edges (); }
 603
 604 }; // class pass_remove_cgraph_callee_edges
 605
 606 } // anon namespace
 607
 608 gimple_opt_pass *
 609 make_pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 610 {
 611   return new pass_remove_cgraph_callee_edges (ctxt);
 612 }