gcc/cgraphbuild.c

   1 /* Callgraph construction.
   2    Copyright (C) 2003-2016 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 (TREE_CODE (decl) == VAR_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 (TREE_CODE (type) == VAR_DECL)
 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 && TREE_CODE (addr) == VAR_DECL
 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 && TREE_CODE (t) == VAR_DECL
 248            && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 249     {
 250       varpool_node *vnode = varpool_node::get_create (t);
 251
 252       ((symtab_node *)data)->create_reference (vnode, IPA_REF_LOAD, stmt);
 253     }
 254   return false;
 255 }
 256
 257 /* Mark store of T.  */
 258
 259 static bool
 260 mark_store (gimple *stmt, tree t, tree, void *data)
 261 {
 262   t = get_base_address (t);
 263   if (t && TREE_CODE (t) == VAR_DECL
 264       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 265     {
 266       varpool_node *vnode = varpool_node::get_create (t);
 267
 268       ((symtab_node *)data)->create_reference (vnode, IPA_REF_STORE, stmt);
 269      }
 270   return false;
 271 }
 272
 273 /* Record all references from cgraph_node that are taken in statement STMT.  */
 274
 275 void
 276 cgraph_node::record_stmt_references (gimple *stmt)
 277 {
 278   walk_stmt_load_store_addr_ops (stmt, this, mark_load, mark_store,
 279                                  mark_address);
 280 }
 281
 282 /* Create cgraph edges for function calls.
 283    Also look for functions and variables having addresses taken.  */
 284
 285 namespace {
 286
 287 const pass_data pass_data_build_cgraph_edges =
 288 {
 289   GIMPLE_PASS, /* type */
 290   "*build_cgraph_edges", /* name */
 291   OPTGROUP_NONE, /* optinfo_flags */
 292   TV_NONE, /* tv_id */
 293   PROP_cfg, /* properties_required */
 294   0, /* properties_provided */
 295   0, /* properties_destroyed */
 296   0, /* todo_flags_start */
 297   0, /* todo_flags_finish */
 298 };
 299
 300 class pass_build_cgraph_edges : public gimple_opt_pass
 301 {
 302 public:
 303   pass_build_cgraph_edges (gcc::context *ctxt)
 304     : gimple_opt_pass (pass_data_build_cgraph_edges, ctxt)
 305   {}
 306
 307   /* opt_pass methods: */
 308   virtual unsigned int execute (function *);
 309
 310 }; // class pass_build_cgraph_edges
 311
 312 unsigned int
 313 pass_build_cgraph_edges::execute (function *fun)
 314 {
 315   basic_block bb;
 316   cgraph_node *node = cgraph_node::get (current_function_decl);
 317   gimple_stmt_iterator gsi;
 318   tree decl;
 319   unsigned ix;
 320
 321   /* Create the callgraph edges and record the nodes referenced by the function.
 322      body.  */
 323   FOR_EACH_BB_FN (bb, fun)
 324     {
 325       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 326         {
 327           gimple *stmt = gsi_stmt (gsi);
 328           tree decl;
 329
 330           if (is_gimple_debug (stmt))
 331             continue;
 332
 333           if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 334             {
 335               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 336                                                          bb);
 337               decl = gimple_call_fndecl (call_stmt);
 338               if (decl)
 339                 node->create_edge (cgraph_node::get_create (decl), call_stmt, bb->count, freq);
 340               else if (gimple_call_internal_p (call_stmt))
 341                 ;
 342               else
 343                 node->create_indirect_edge (call_stmt,
 344                                             gimple_call_flags (call_stmt),
 345                                             bb->count, freq);
 346             }
 347           node->record_stmt_references (stmt);
 348           if (gomp_parallel *omp_par_stmt = dyn_cast <gomp_parallel *> (stmt))
 349             {
 350               tree fn = gimple_omp_parallel_child_fn (omp_par_stmt);
 351               node->create_reference (cgraph_node::get_create (fn),
 352                                       IPA_REF_ADDR, stmt);
 353             }
 354           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 355             {
 356               tree fn = gimple_omp_task_child_fn (stmt);
 357               if (fn)
 358                 node->create_reference (cgraph_node::get_create (fn),
 359                                         IPA_REF_ADDR, stmt);
 360               fn = gimple_omp_task_copy_fn (stmt);
 361               if (fn)
 362                 node->create_reference (cgraph_node::get_create (fn),
 363                                         IPA_REF_ADDR, stmt);
 364             }
 365         }
 366       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 367         node->record_stmt_references (gsi_stmt (gsi));
 368    }
 369
 370   /* Look for initializers of constant variables and private statics.  */
 371   FOR_EACH_LOCAL_DECL (fun, ix, decl)
 372     if (TREE_CODE (decl) == VAR_DECL
 373         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
 374         && !DECL_HAS_VALUE_EXPR_P (decl)
 375         && TREE_TYPE (decl) != error_mark_node)
 376       varpool_node::finalize_decl (decl);
 377   record_eh_tables (node, fun);
 378
 379   return 0;
 380 }
 381
 382 } // anon namespace
 383
 384 gimple_opt_pass *
 385 make_pass_build_cgraph_edges (gcc::context *ctxt)
 386 {
 387   return new pass_build_cgraph_edges (ctxt);
 388 }
 389
 390 /* Record references to functions and other variables present in the
 391    initial value of DECL, a variable.
 392    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 393
 394 void
 395 record_references_in_initializer (tree decl, bool only_vars)
 396 {
 397   varpool_node *node = varpool_node::get_create (decl);
 398   hash_set<tree> visited_nodes;
 399   record_reference_ctx ctx = {false, NULL};
 400
 401   ctx.varpool_node = node;
 402   ctx.only_vars = only_vars;
 403   walk_tree (&DECL_INITIAL (decl), record_reference,
 404              &ctx, &visited_nodes);
 405 }
 406
 407 /* Rebuild cgraph edges for current function node.  This needs to be run after
 408    passes that don't update the cgraph.  */
 409
 410 unsigned int
 411 cgraph_edge::rebuild_edges (void)
 412 {
 413   basic_block bb;
 414   cgraph_node *node = cgraph_node::get (current_function_decl);
 415   gimple_stmt_iterator gsi;
 416
 417   node->remove_callees ();
 418   node->remove_all_references ();
 419
 420   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 421
 422   FOR_EACH_BB_FN (bb, cfun)
 423     {
 424       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 425         {
 426           gimple *stmt = gsi_stmt (gsi);
 427           tree decl;
 428
 429           if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 430             {
 431               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 432                                                          bb);
 433               decl = gimple_call_fndecl (call_stmt);
 434               if (decl)
 435                 node->create_edge (cgraph_node::get_create (decl), call_stmt,
 436                                    bb->count, freq);
 437               else if (gimple_call_internal_p (call_stmt))
 438                 ;
 439               else
 440                 node->create_indirect_edge (call_stmt,
 441                                             gimple_call_flags (call_stmt),
 442                                             bb->count, freq);
 443             }
 444           node->record_stmt_references (stmt);
 445         }
 446       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 447         node->record_stmt_references (gsi_stmt (gsi));
 448     }
 449   record_eh_tables (node, cfun);
 450   gcc_assert (!node->global.inlined_to);
 451
 452   if (node->instrumented_version
 453       && !node->instrumentation_clone)
 454     node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
 455
 456   return 0;
 457 }
 458
 459 /* Rebuild cgraph references for current function node.  This needs to be run
 460    after passes that don't update the cgraph.  */
 461
 462 void
 463 cgraph_edge::rebuild_references (void)
 464 {
 465   basic_block bb;
 466   cgraph_node *node = cgraph_node::get (current_function_decl);
 467   gimple_stmt_iterator gsi;
 468   ipa_ref *ref = NULL;
 469   int i;
 470
 471   /* Keep speculative references for further cgraph edge expansion.  */
 472   for (i = 0; node->iterate_reference (i, ref);)
 473     if (!ref->speculative)
 474       ref->remove_reference ();
 475     else
 476       i++;
 477
 478   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 479
 480   FOR_EACH_BB_FN (bb, cfun)
 481     {
 482       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 483         node->record_stmt_references (gsi_stmt (gsi));
 484       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 485         node->record_stmt_references (gsi_stmt (gsi));
 486     }
 487   record_eh_tables (node, cfun);
 488
 489   if (node->instrumented_version
 490       && !node->instrumentation_clone)
 491     node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
 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 *)
 519   {
 520     return cgraph_edge::rebuild_edges ();
 521   }
 522
 523 }; // class pass_rebuild_cgraph_edges
 524
 525 } // anon namespace
 526
 527 gimple_opt_pass *
 528 make_pass_rebuild_cgraph_edges (gcc::context *ctxt)
 529 {
 530   return new pass_rebuild_cgraph_edges (ctxt);
 531 }
 532
 533
 534 namespace {
 535
 536 const pass_data pass_data_remove_cgraph_callee_edges =
 537 {
 538   GIMPLE_PASS, /* type */
 539   "*remove_cgraph_callee_edges", /* name */
 540   OPTGROUP_NONE, /* optinfo_flags */
 541   TV_NONE, /* tv_id */
 542   0, /* properties_required */
 543   0, /* properties_provided */
 544   0, /* properties_destroyed */
 545   0, /* todo_flags_start */
 546   0, /* todo_flags_finish */
 547 };
 548
 549 class pass_remove_cgraph_callee_edges : public gimple_opt_pass
 550 {
 551 public:
 552   pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 553     : gimple_opt_pass (pass_data_remove_cgraph_callee_edges, ctxt)
 554   {}
 555
 556   /* opt_pass methods: */
 557   opt_pass * clone () {
 558     return new pass_remove_cgraph_callee_edges (m_ctxt);
 559   }
 560   virtual unsigned int execute (function *);
 561
 562 }; // class pass_remove_cgraph_callee_edges
 563
 564 unsigned int
 565 pass_remove_cgraph_callee_edges::execute (function *)
 566 {
 567   cgraph_node *node = cgraph_node::get (current_function_decl);
 568   node->remove_callees ();
 569   node->remove_all_references ();
 570   return 0;
 571 }
 572
 573 } // anon namespace
 574
 575 gimple_opt_pass *
 576 make_pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 577 {
 578   return new pass_remove_cgraph_callee_edges (ctxt);
 579 }