gcc/cgraphbuild.c

   1 /* Callgraph construction.
   2    Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4    Contributed by Jan Hubicka
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "tree.h"
  27 #include "tree-flow.h"
  28 #include "langhooks.h"
  29 #include "pointer-set.h"
  30 #include "cgraph.h"
  31 #include "intl.h"
  32 #include "gimple.h"
  33 #include "tree-pass.h"
  34 #include "ipa-utils.h"
  35 #include "except.h"
  36
  37 /* Context of record_reference.  */
  38 struct record_reference_ctx
  39 {
  40   bool only_vars;
  41   struct varpool_node *varpool_node;
  42 };
  43
  44 /* Walk tree and record all calls and references to functions/variables.
  45    Called via walk_tree: TP is pointer to tree to be examined.
  46    When DATA is non-null, record references to callgraph.
  47    */
  48
  49 static tree
  50 record_reference (tree *tp, int *walk_subtrees, void *data)
  51 {
  52   tree t = *tp;
  53   tree decl;
  54   struct record_reference_ctx *ctx = (struct record_reference_ctx *)data;
  55
  56   switch (TREE_CODE (t))
  57     {
  58     case VAR_DECL:
  59     case FUNCTION_DECL:
  60       gcc_unreachable ();
  61       break;
  62
  63     case FDESC_EXPR:
  64     case ADDR_EXPR:
  65       /* Record dereferences to the functions.  This makes the
  66          functions reachable unconditionally.  */
  67       decl = get_base_var (*tp);
  68       if (TREE_CODE (decl) == FUNCTION_DECL)
  69         {
  70           if (!ctx->only_vars)
  71           cgraph_mark_address_taken_node (cgraph_node (decl));
  72           ipa_record_reference (NULL, ctx->varpool_node,
  73                                 cgraph_node (decl), NULL,
  74                                 IPA_REF_ADDR, NULL);
  75         }
  76
  77       if (TREE_CODE (decl) == VAR_DECL)
  78         {
  79           struct varpool_node *vnode = varpool_node (decl);
  80           if (lang_hooks.callgraph.analyze_expr)
  81             lang_hooks.callgraph.analyze_expr (&decl, walk_subtrees);
  82           varpool_mark_needed_node (vnode);
  83           if (vnode->alias && vnode->extra_name)
  84             vnode = vnode->extra_name;
  85           ipa_record_reference (NULL, ctx->varpool_node,
  86                                 NULL, vnode,
  87                                 IPA_REF_ADDR, NULL);
  88         }
  89       *walk_subtrees = 0;
  90       break;
  91
  92     default:
  93       /* Save some cycles by not walking types and declaration as we
  94          won't find anything useful there anyway.  */
  95       if (IS_TYPE_OR_DECL_P (*tp))
  96         {
  97           *walk_subtrees = 0;
  98           break;
  99         }
 100
 101       if ((unsigned int) TREE_CODE (t) >= LAST_AND_UNUSED_TREE_CODE)
 102         return lang_hooks.callgraph.analyze_expr (tp, walk_subtrees);
 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               struct varpool_node *vnode = varpool_node (type);
 127               varpool_mark_needed_node (vnode);
 128               ipa_record_reference (node, NULL,
 129                                     NULL, vnode,
 130                                     IPA_REF_ADDR, NULL);
 131             }
 132         }
 133     }
 134 }
 135
 136 /* Record all references we will introduce by producing EH tables
 137    for NODE.  */
 138
 139 static void
 140 record_eh_tables (struct cgraph_node *node, struct function *fun)
 141 {
 142   eh_region i;
 143
 144   i = fun->eh->region_tree;
 145   if (!i)
 146     return;
 147
 148   while (1)
 149     {
 150       switch (i->type)
 151         {
 152         case ERT_CLEANUP:
 153         case ERT_MUST_NOT_THROW:
 154           break;
 155
 156         case ERT_TRY:
 157           {
 158             eh_catch c;
 159             for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
 160               record_type_list (node, c->type_list);
 161           }
 162           break;
 163
 164         case ERT_ALLOWED_EXCEPTIONS:
 165           record_type_list (node, i->u.allowed.type_list);
 166           break;
 167         }
 168       /* If there are sub-regions, process them.  */
 169       if (i->inner)
 170         i = i->inner;
 171       /* If there are peers, process them.  */
 172       else if (i->next_peer)
 173         i = i->next_peer;
 174       /* Otherwise, step back up the tree to the next peer.  */
 175       else
 176         {
 177           do
 178             {
 179               i = i->outer;
 180               if (i == NULL)
 181                 return;
 182             }
 183           while (i->next_peer == NULL);
 184           i = i->next_peer;
 185         }
 186     }
 187 }
 188
 189 /* Reset inlining information of all incoming call edges of NODE.  */
 190
 191 void
 192 reset_inline_failed (struct cgraph_node *node)
 193 {
 194   struct cgraph_edge *e;
 195
 196   for (e = node->callers; e; e = e->next_caller)
 197     {
 198       e->callee->global.inlined_to = NULL;
 199       if (!node->analyzed)
 200         e->inline_failed = CIF_BODY_NOT_AVAILABLE;
 201       else if (node->local.redefined_extern_inline)
 202         e->inline_failed = CIF_REDEFINED_EXTERN_INLINE;
 203       else if (!node->local.inlinable)
 204         e->inline_failed = CIF_FUNCTION_NOT_INLINABLE;
 205       else if (e->call_stmt_cannot_inline_p)
 206         e->inline_failed = CIF_MISMATCHED_ARGUMENTS;
 207       else
 208         e->inline_failed = CIF_FUNCTION_NOT_CONSIDERED;
 209     }
 210 }
 211
 212 /* Computes the frequency of the call statement so that it can be stored in
 213    cgraph_edge.  BB is the basic block of the call statement.  */
 214 int
 215 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 216 {
 217   int entry_freq = ENTRY_BLOCK_PTR_FOR_FUNCTION
 218                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 219   int freq = bb->frequency;
 220
 221   if (profile_status_for_function (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 222     return CGRAPH_FREQ_BASE;
 223
 224   if (!entry_freq)
 225     entry_freq = 1, freq++;
 226
 227   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 228   if (freq > CGRAPH_FREQ_MAX)
 229     freq = CGRAPH_FREQ_MAX;
 230
 231   return freq;
 232 }
 233
 234 /* Mark address taken in STMT.  */
 235
 236 static bool
 237 mark_address (gimple stmt, tree addr, void *data)
 238 {
 239   addr = get_base_address (addr);
 240   if (TREE_CODE (addr) == FUNCTION_DECL)
 241     {
 242       struct cgraph_node *node = cgraph_node (addr);
 243       cgraph_mark_address_taken_node (node);
 244       ipa_record_reference ((struct cgraph_node *)data, NULL,
 245                             node, NULL,
 246                             IPA_REF_ADDR, stmt);
 247     }
 248   else if (addr && TREE_CODE (addr) == VAR_DECL
 249            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 250     {
 251       struct varpool_node *vnode = varpool_node (addr);
 252       int walk_subtrees;
 253
 254       if (lang_hooks.callgraph.analyze_expr)
 255         lang_hooks.callgraph.analyze_expr (&addr, &walk_subtrees);
 256       varpool_mark_needed_node (vnode);
 257       if (vnode->alias && vnode->extra_name)
 258         vnode = vnode->extra_name;
 259       ipa_record_reference ((struct cgraph_node *)data, NULL,
 260                             NULL, vnode,
 261                             IPA_REF_ADDR, stmt);
 262     }
 263
 264   return false;
 265 }
 266
 267 /* Mark load of T.  */
 268
 269 static bool
 270 mark_load (gimple stmt, tree t, void *data)
 271 {
 272   t = get_base_address (t);
 273   if (t && TREE_CODE (t) == FUNCTION_DECL)
 274     {
 275       /* ??? This can happen on platforms with descriptors when these are
 276          directly manipulated in the code.  Pretend that it's an address.  */
 277       struct cgraph_node *node = cgraph_node (t);
 278       cgraph_mark_address_taken_node (node);
 279       ipa_record_reference ((struct cgraph_node *)data, NULL,
 280                             node, NULL,
 281                             IPA_REF_ADDR, stmt);
 282     }
 283   else if (t && TREE_CODE (t) == VAR_DECL
 284            && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 285     {
 286       struct varpool_node *vnode = varpool_node (t);
 287       int walk_subtrees;
 288
 289       if (lang_hooks.callgraph.analyze_expr)
 290         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 291       varpool_mark_needed_node (vnode);
 292       if (vnode->alias && vnode->extra_name)
 293         vnode = vnode->extra_name;
 294       ipa_record_reference ((struct cgraph_node *)data, NULL,
 295                             NULL, vnode,
 296                             IPA_REF_LOAD, stmt);
 297     }
 298   return false;
 299 }
 300
 301 /* Mark store of T.  */
 302
 303 static bool
 304 mark_store (gimple stmt, tree t, void *data)
 305 {
 306   t = get_base_address (t);
 307   if (t && TREE_CODE (t) == VAR_DECL
 308       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 309     {
 310       struct varpool_node *vnode = varpool_node (t);
 311       int walk_subtrees;
 312
 313       if (lang_hooks.callgraph.analyze_expr)
 314         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 315       varpool_mark_needed_node (vnode);
 316       if (vnode->alias && vnode->extra_name)
 317         vnode = vnode->extra_name;
 318       ipa_record_reference ((struct cgraph_node *)data, NULL,
 319                             NULL, vnode,
 320                             IPA_REF_STORE, stmt);
 321      }
 322   return false;
 323 }
 324
 325 /* Create cgraph edges for function calls.
 326    Also look for functions and variables having addresses taken.  */
 327
 328 static unsigned int
 329 build_cgraph_edges (void)
 330 {
 331   basic_block bb;
 332   struct cgraph_node *node = cgraph_node (current_function_decl);
 333   struct pointer_set_t *visited_nodes = pointer_set_create ();
 334   gimple_stmt_iterator gsi;
 335   tree decl;
 336   unsigned ix;
 337
 338   /* Create the callgraph edges and record the nodes referenced by the function.
 339      body.  */
 340   FOR_EACH_BB (bb)
 341     {
 342       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 343         {
 344           gimple stmt = gsi_stmt (gsi);
 345           tree decl;
 346
 347           if (is_gimple_call (stmt))
 348             {
 349               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 350                                                          bb);
 351               decl = gimple_call_fndecl (stmt);
 352               if (decl)
 353                 cgraph_create_edge (node, cgraph_node (decl), stmt,
 354                                     bb->count, freq,
 355                                     bb->loop_depth);
 356               else
 357                 cgraph_create_indirect_edge (node, stmt,
 358                                              gimple_call_flags (stmt),
 359                                              bb->count, freq,
 360                                              bb->loop_depth);
 361             }
 362           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 363                                          mark_store, mark_address);
 364           if (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
 365               && gimple_omp_parallel_child_fn (stmt))
 366             {
 367               tree fn = gimple_omp_parallel_child_fn (stmt);
 368               ipa_record_reference (node, NULL, cgraph_node (fn),
 369                                     NULL, IPA_REF_ADDR, stmt);
 370             }
 371           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 372             {
 373               tree fn = gimple_omp_task_child_fn (stmt);
 374               if (fn)
 375                 ipa_record_reference (node, NULL, cgraph_node (fn),
 376                                       NULL, IPA_REF_ADDR, stmt);
 377               fn = gimple_omp_task_copy_fn (stmt);
 378               if (fn)
 379                 ipa_record_reference (node, NULL, cgraph_node (fn),
 380                                       NULL, IPA_REF_ADDR, stmt);
 381             }
 382         }
 383       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 384         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 385                                        mark_load, mark_store, mark_address);
 386    }
 387
 388   /* Look for initializers of constant variables and private statics.  */
 389   FOR_EACH_LOCAL_DECL (cfun, ix, decl)
 390     if (TREE_CODE (decl) == VAR_DECL
 391         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl)))
 392       varpool_finalize_decl (decl);
 393   record_eh_tables (node, cfun);
 394
 395   pointer_set_destroy (visited_nodes);
 396   return 0;
 397 }
 398
 399 struct gimple_opt_pass pass_build_cgraph_edges =
 400 {
 401  {
 402   GIMPLE_PASS,
 403   "*build_cgraph_edges",                        /* name */
 404   NULL,                                 /* gate */
 405   build_cgraph_edges,                   /* execute */
 406   NULL,                                 /* sub */
 407   NULL,                                 /* next */
 408   0,                                    /* static_pass_number */
 409   TV_NONE,                              /* tv_id */
 410   PROP_cfg,                             /* properties_required */
 411   0,                                    /* properties_provided */
 412   0,                                    /* properties_destroyed */
 413   0,                                    /* todo_flags_start */
 414   0                                     /* todo_flags_finish */
 415  }
 416 };
 417
 418 /* Record references to functions and other variables present in the
 419    initial value of DECL, a variable.
 420    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 421
 422 void
 423 record_references_in_initializer (tree decl, bool only_vars)
 424 {
 425   struct pointer_set_t *visited_nodes = pointer_set_create ();
 426   struct varpool_node *node = varpool_node (decl);
 427   struct record_reference_ctx ctx = {false, NULL};
 428
 429   ctx.varpool_node = node;
 430   ctx.only_vars = only_vars;
 431   walk_tree (&DECL_INITIAL (decl), record_reference,
 432              &ctx, visited_nodes);
 433   pointer_set_destroy (visited_nodes);
 434 }
 435
 436 /* Rebuild cgraph edges for current function node.  This needs to be run after
 437    passes that don't update the cgraph.  */
 438
 439 unsigned int
 440 rebuild_cgraph_edges (void)
 441 {
 442   basic_block bb;
 443   struct cgraph_node *node = cgraph_node (current_function_decl);
 444   gimple_stmt_iterator gsi;
 445
 446   cgraph_node_remove_callees (node);
 447   ipa_remove_all_references (&node->ref_list);
 448
 449   node->count = ENTRY_BLOCK_PTR->count;
 450
 451   FOR_EACH_BB (bb)
 452     {
 453       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 454         {
 455           gimple stmt = gsi_stmt (gsi);
 456           tree decl;
 457
 458           if (is_gimple_call (stmt))
 459             {
 460               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 461                                                          bb);
 462               decl = gimple_call_fndecl (stmt);
 463               if (decl)
 464                 cgraph_create_edge (node, cgraph_node (decl), stmt,
 465                                     bb->count, freq,
 466                                     bb->loop_depth);
 467               else
 468                 cgraph_create_indirect_edge (node, stmt,
 469                                              gimple_call_flags (stmt),
 470                                              bb->count, freq,
 471                                              bb->loop_depth);
 472             }
 473           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 474                                          mark_store, mark_address);
 475
 476         }
 477       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 478         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 479                                        mark_load, mark_store, mark_address);
 480     }
 481   record_eh_tables (node, cfun);
 482   gcc_assert (!node->global.inlined_to);
 483
 484   return 0;
 485 }
 486
 487 /* Rebuild cgraph edges for current function node.  This needs to be run after
 488    passes that don't update the cgraph.  */
 489
 490 void
 491 cgraph_rebuild_references (void)
 492 {
 493   basic_block bb;
 494   struct cgraph_node *node = cgraph_node (current_function_decl);
 495   gimple_stmt_iterator gsi;
 496
 497   ipa_remove_all_references (&node->ref_list);
 498
 499   node->count = ENTRY_BLOCK_PTR->count;
 500
 501   FOR_EACH_BB (bb)
 502     {
 503       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 504         {
 505           gimple stmt = gsi_stmt (gsi);
 506
 507           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 508                                          mark_store, mark_address);
 509
 510         }
 511       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 512         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 513                                        mark_load, mark_store, mark_address);
 514     }
 515   record_eh_tables (node, cfun);
 516 }
 517
 518 struct gimple_opt_pass pass_rebuild_cgraph_edges =
 519 {
 520  {
 521   GIMPLE_PASS,
 522   "*rebuild_cgraph_edges",              /* name */
 523   NULL,                                 /* gate */
 524   rebuild_cgraph_edges,                 /* execute */
 525   NULL,                                 /* sub */
 526   NULL,                                 /* next */
 527   0,                                    /* static_pass_number */
 528   TV_CGRAPH,                            /* tv_id */
 529   PROP_cfg,                             /* properties_required */
 530   0,                                    /* properties_provided */
 531   0,                                    /* properties_destroyed */
 532   0,                                    /* todo_flags_start */
 533   0,                                    /* todo_flags_finish */
 534  }
 535 };
 536
 537
 538 static unsigned int
 539 remove_cgraph_callee_edges (void)
 540 {
 541   cgraph_node_remove_callees (cgraph_node (current_function_decl));
 542   return 0;
 543 }
 544
 545 struct gimple_opt_pass pass_remove_cgraph_callee_edges =
 546 {
 547  {
 548   GIMPLE_PASS,
 549   "*remove_cgraph_callee_edges",                /* name */
 550   NULL,                                 /* gate */
 551   remove_cgraph_callee_edges,           /* execute */
 552   NULL,                                 /* sub */
 553   NULL,                                 /* next */
 554   0,                                    /* static_pass_number */
 555   TV_NONE,                              /* tv_id */
 556   0,                                    /* properties_required */
 557   0,                                    /* properties_provided */
 558   0,                                    /* properties_destroyed */
 559   0,                                    /* todo_flags_start */
 560   0,                                    /* todo_flags_finish */
 561  }
 562 };