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 #include "ipa-inline.h"
  37
  38 /* Context of record_reference.  */
  39 struct record_reference_ctx
  40 {
  41   bool only_vars;
  42   struct varpool_node *varpool_node;
  43 };
  44
  45 /* Walk tree and record all calls and references to functions/variables.
  46    Called via walk_tree: TP is pointer to tree to be examined.
  47    When DATA is non-null, record references to callgraph.
  48    */
  49
  50 static tree
  51 record_reference (tree *tp, int *walk_subtrees, void *data)
  52 {
  53   tree t = *tp;
  54   tree decl;
  55   struct record_reference_ctx *ctx = (struct record_reference_ctx *)data;
  56
  57   t = canonicalize_constructor_val (t);
  58   if (!t)
  59     t = *tp;
  60   else if (t != *tp)
  61     *tp = t;
  62
  63   switch (TREE_CODE (t))
  64     {
  65     case VAR_DECL:
  66     case FUNCTION_DECL:
  67       gcc_unreachable ();
  68       break;
  69
  70     case FDESC_EXPR:
  71     case ADDR_EXPR:
  72       /* Record dereferences to the functions.  This makes the
  73          functions reachable unconditionally.  */
  74       decl = get_base_var (*tp);
  75       if (TREE_CODE (decl) == FUNCTION_DECL)
  76         {
  77           struct cgraph_node *node = cgraph_get_create_node (decl);
  78           if (!ctx->only_vars)
  79             cgraph_mark_address_taken_node (node);
  80           ipa_record_reference (NULL, ctx->varpool_node, node, NULL,
  81                                 IPA_REF_ADDR, NULL);
  82         }
  83
  84       if (TREE_CODE (decl) == VAR_DECL)
  85         {
  86           struct varpool_node *vnode = varpool_node (decl);
  87           if (lang_hooks.callgraph.analyze_expr)
  88             lang_hooks.callgraph.analyze_expr (&decl, walk_subtrees);
  89           varpool_mark_needed_node (vnode);
  90           if (vnode->alias && vnode->extra_name)
  91             vnode = vnode->extra_name;
  92           ipa_record_reference (NULL, ctx->varpool_node,
  93                                 NULL, vnode,
  94                                 IPA_REF_ADDR, NULL);
  95         }
  96       *walk_subtrees = 0;
  97       break;
  98
  99     default:
 100       /* Save some cycles by not walking types and declaration as we
 101          won't find anything useful there anyway.  */
 102       if (IS_TYPE_OR_DECL_P (*tp))
 103         {
 104           *walk_subtrees = 0;
 105           break;
 106         }
 107
 108       if ((unsigned int) TREE_CODE (t) >= LAST_AND_UNUSED_TREE_CODE)
 109         return lang_hooks.callgraph.analyze_expr (tp, walk_subtrees);
 110       break;
 111     }
 112
 113   return NULL_TREE;
 114 }
 115
 116 /* Record references to typeinfos in the type list LIST.  */
 117
 118 static void
 119 record_type_list (struct cgraph_node *node, tree list)
 120 {
 121   for (; list; list = TREE_CHAIN (list))
 122     {
 123       tree type = TREE_VALUE (list);
 124
 125       if (TYPE_P (type))
 126         type = lookup_type_for_runtime (type);
 127       STRIP_NOPS (type);
 128       if (TREE_CODE (type) == ADDR_EXPR)
 129         {
 130           type = TREE_OPERAND (type, 0);
 131           if (TREE_CODE (type) == VAR_DECL)
 132             {
 133               struct varpool_node *vnode = varpool_node (type);
 134               varpool_mark_needed_node (vnode);
 135               ipa_record_reference (node, NULL,
 136                                     NULL, vnode,
 137                                     IPA_REF_ADDR, NULL);
 138             }
 139         }
 140     }
 141 }
 142
 143 /* Record all references we will introduce by producing EH tables
 144    for NODE.  */
 145
 146 static void
 147 record_eh_tables (struct cgraph_node *node, struct function *fun)
 148 {
 149   eh_region i;
 150
 151   if (DECL_FUNCTION_PERSONALITY (node->decl))
 152     ipa_record_reference (node, NULL,
 153                cgraph_get_create_node (DECL_FUNCTION_PERSONALITY (node->decl)),
 154                NULL, IPA_REF_ADDR, NULL);
 155
 156   i = fun->eh->region_tree;
 157   if (!i)
 158     return;
 159
 160   while (1)
 161     {
 162       switch (i->type)
 163         {
 164         case ERT_CLEANUP:
 165         case ERT_MUST_NOT_THROW:
 166           break;
 167
 168         case ERT_TRY:
 169           {
 170             eh_catch c;
 171             for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
 172               record_type_list (node, c->type_list);
 173           }
 174           break;
 175
 176         case ERT_ALLOWED_EXCEPTIONS:
 177           record_type_list (node, i->u.allowed.type_list);
 178           break;
 179         }
 180       /* If there are sub-regions, process them.  */
 181       if (i->inner)
 182         i = i->inner;
 183       /* If there are peers, process them.  */
 184       else if (i->next_peer)
 185         i = i->next_peer;
 186       /* Otherwise, step back up the tree to the next peer.  */
 187       else
 188         {
 189           do
 190             {
 191               i = i->outer;
 192               if (i == NULL)
 193                 return;
 194             }
 195           while (i->next_peer == NULL);
 196           i = i->next_peer;
 197         }
 198     }
 199 }
 200
 201 /* Reset inlining information of all incoming call edges of NODE.  */
 202
 203 void
 204 reset_inline_failed (struct cgraph_node *node)
 205 {
 206   struct cgraph_edge *e;
 207
 208   for (e = node->callers; e; e = e->next_caller)
 209     {
 210       e->callee->global.inlined_to = NULL;
 211       initialize_inline_failed (e);
 212     }
 213 }
 214
 215 /* Computes the frequency of the call statement so that it can be stored in
 216    cgraph_edge.  BB is the basic block of the call statement.  */
 217 int
 218 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 219 {
 220   int entry_freq = ENTRY_BLOCK_PTR_FOR_FUNCTION
 221                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 222   int freq = bb->frequency;
 223
 224   if (profile_status_for_function (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 225     return CGRAPH_FREQ_BASE;
 226
 227   if (!entry_freq)
 228     entry_freq = 1, freq++;
 229
 230   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 231   if (freq > CGRAPH_FREQ_MAX)
 232     freq = CGRAPH_FREQ_MAX;
 233
 234   return freq;
 235 }
 236
 237 /* Mark address taken in STMT.  */
 238
 239 static bool
 240 mark_address (gimple stmt, tree addr, void *data)
 241 {
 242   addr = get_base_address (addr);
 243   if (TREE_CODE (addr) == FUNCTION_DECL)
 244     {
 245       struct cgraph_node *node = cgraph_get_create_node (addr);
 246       cgraph_mark_address_taken_node (node);
 247       ipa_record_reference ((struct cgraph_node *)data, NULL,
 248                             node, NULL,
 249                             IPA_REF_ADDR, stmt);
 250     }
 251   else if (addr && TREE_CODE (addr) == VAR_DECL
 252            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 253     {
 254       struct varpool_node *vnode = varpool_node (addr);
 255       int walk_subtrees;
 256
 257       if (lang_hooks.callgraph.analyze_expr)
 258         lang_hooks.callgraph.analyze_expr (&addr, &walk_subtrees);
 259       varpool_mark_needed_node (vnode);
 260       if (vnode->alias && vnode->extra_name)
 261         vnode = vnode->extra_name;
 262       ipa_record_reference ((struct cgraph_node *)data, NULL,
 263                             NULL, vnode,
 264                             IPA_REF_ADDR, stmt);
 265     }
 266
 267   return false;
 268 }
 269
 270 /* Mark load of T.  */
 271
 272 static bool
 273 mark_load (gimple stmt, tree t, void *data)
 274 {
 275   t = get_base_address (t);
 276   if (t && TREE_CODE (t) == FUNCTION_DECL)
 277     {
 278       /* ??? This can happen on platforms with descriptors when these are
 279          directly manipulated in the code.  Pretend that it's an address.  */
 280       struct cgraph_node *node = cgraph_get_create_node (t);
 281       cgraph_mark_address_taken_node (node);
 282       ipa_record_reference ((struct cgraph_node *)data, NULL,
 283                             node, NULL,
 284                             IPA_REF_ADDR, stmt);
 285     }
 286   else if (t && TREE_CODE (t) == VAR_DECL
 287            && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 288     {
 289       struct varpool_node *vnode = varpool_node (t);
 290       int walk_subtrees;
 291
 292       if (lang_hooks.callgraph.analyze_expr)
 293         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 294       varpool_mark_needed_node (vnode);
 295       if (vnode->alias && vnode->extra_name)
 296         vnode = vnode->extra_name;
 297       ipa_record_reference ((struct cgraph_node *)data, NULL,
 298                             NULL, vnode,
 299                             IPA_REF_LOAD, stmt);
 300     }
 301   return false;
 302 }
 303
 304 /* Mark store of T.  */
 305
 306 static bool
 307 mark_store (gimple stmt, tree t, void *data)
 308 {
 309   t = get_base_address (t);
 310   if (t && TREE_CODE (t) == VAR_DECL
 311       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 312     {
 313       struct varpool_node *vnode = varpool_node (t);
 314       int walk_subtrees;
 315
 316       if (lang_hooks.callgraph.analyze_expr)
 317         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 318       varpool_mark_needed_node (vnode);
 319       if (vnode->alias && vnode->extra_name)
 320         vnode = vnode->extra_name;
 321       ipa_record_reference ((struct cgraph_node *)data, NULL,
 322                             NULL, vnode,
 323                             IPA_REF_STORE, stmt);
 324      }
 325   return false;
 326 }
 327
 328 /* Create cgraph edges for function calls.
 329    Also look for functions and variables having addresses taken.  */
 330
 331 static unsigned int
 332 build_cgraph_edges (void)
 333 {
 334   basic_block bb;
 335   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 336   struct pointer_set_t *visited_nodes = pointer_set_create ();
 337   gimple_stmt_iterator gsi;
 338   tree decl;
 339   unsigned ix;
 340
 341   /* Create the callgraph edges and record the nodes referenced by the function.
 342      body.  */
 343   FOR_EACH_BB (bb)
 344     {
 345       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 346         {
 347           gimple stmt = gsi_stmt (gsi);
 348           tree decl;
 349
 350           if (is_gimple_call (stmt))
 351             {
 352               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 353                                                          bb);
 354               decl = gimple_call_fndecl (stmt);
 355               if (decl)
 356                 cgraph_create_edge (node, cgraph_get_create_node (decl),
 357                                     stmt, bb->count, freq);
 358               else
 359                 cgraph_create_indirect_edge (node, stmt,
 360                                              gimple_call_flags (stmt),
 361                                              bb->count, freq);
 362             }
 363           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 364                                          mark_store, mark_address);
 365           if (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
 366               && gimple_omp_parallel_child_fn (stmt))
 367             {
 368               tree fn = gimple_omp_parallel_child_fn (stmt);
 369               ipa_record_reference (node, NULL, cgraph_get_create_node (fn),
 370                                     NULL, IPA_REF_ADDR, stmt);
 371             }
 372           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 373             {
 374               tree fn = gimple_omp_task_child_fn (stmt);
 375               if (fn)
 376                 ipa_record_reference (node, NULL, cgraph_get_create_node (fn),
 377                                       NULL, IPA_REF_ADDR, stmt);
 378               fn = gimple_omp_task_copy_fn (stmt);
 379               if (fn)
 380                 ipa_record_reference (node, NULL, cgraph_get_create_node (fn),
 381                                       NULL, IPA_REF_ADDR, stmt);
 382             }
 383         }
 384       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 385         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 386                                        mark_load, mark_store, mark_address);
 387    }
 388
 389   /* Look for initializers of constant variables and private statics.  */
 390   FOR_EACH_LOCAL_DECL (cfun, ix, decl)
 391     if (TREE_CODE (decl) == VAR_DECL
 392         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl)))
 393       varpool_finalize_decl (decl);
 394   record_eh_tables (node, cfun);
 395
 396   pointer_set_destroy (visited_nodes);
 397   return 0;
 398 }
 399
 400 struct gimple_opt_pass pass_build_cgraph_edges =
 401 {
 402  {
 403   GIMPLE_PASS,
 404   "*build_cgraph_edges",                        /* name */
 405   NULL,                                 /* gate */
 406   build_cgraph_edges,                   /* execute */
 407   NULL,                                 /* sub */
 408   NULL,                                 /* next */
 409   0,                                    /* static_pass_number */
 410   TV_NONE,                              /* tv_id */
 411   PROP_cfg,                             /* properties_required */
 412   0,                                    /* properties_provided */
 413   0,                                    /* properties_destroyed */
 414   0,                                    /* todo_flags_start */
 415   0                                     /* todo_flags_finish */
 416  }
 417 };
 418
 419 /* Record references to functions and other variables present in the
 420    initial value of DECL, a variable.
 421    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 422
 423 void
 424 record_references_in_initializer (tree decl, bool only_vars)
 425 {
 426   struct pointer_set_t *visited_nodes = pointer_set_create ();
 427   struct varpool_node *node = varpool_node (decl);
 428   struct record_reference_ctx ctx = {false, NULL};
 429
 430   ctx.varpool_node = node;
 431   ctx.only_vars = only_vars;
 432   walk_tree (&DECL_INITIAL (decl), record_reference,
 433              &ctx, visited_nodes);
 434   pointer_set_destroy (visited_nodes);
 435 }
 436
 437 /* Rebuild cgraph edges for current function node.  This needs to be run after
 438    passes that don't update the cgraph.  */
 439
 440 unsigned int
 441 rebuild_cgraph_edges (void)
 442 {
 443   basic_block bb;
 444   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 445   gimple_stmt_iterator gsi;
 446
 447   cgraph_node_remove_callees (node);
 448   ipa_remove_all_references (&node->ref_list);
 449
 450   node->count = ENTRY_BLOCK_PTR->count;
 451
 452   FOR_EACH_BB (bb)
 453     {
 454       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 455         {
 456           gimple stmt = gsi_stmt (gsi);
 457           tree decl;
 458
 459           if (is_gimple_call (stmt))
 460             {
 461               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 462                                                          bb);
 463               decl = gimple_call_fndecl (stmt);
 464               if (decl)
 465                 cgraph_create_edge (node, cgraph_get_create_node (decl), stmt,
 466                                     bb->count, freq);
 467               else
 468                 cgraph_create_indirect_edge (node, stmt,
 469                                              gimple_call_flags (stmt),
 470                                              bb->count, freq);
 471             }
 472           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 473                                          mark_store, mark_address);
 474
 475         }
 476       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 477         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 478                                        mark_load, mark_store, mark_address);
 479     }
 480   record_eh_tables (node, cfun);
 481   gcc_assert (!node->global.inlined_to);
 482
 483   return 0;
 484 }
 485
 486 /* Rebuild cgraph edges for current function node.  This needs to be run after
 487    passes that don't update the cgraph.  */
 488
 489 void
 490 cgraph_rebuild_references (void)
 491 {
 492   basic_block bb;
 493   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 494   gimple_stmt_iterator gsi;
 495
 496   ipa_remove_all_references (&node->ref_list);
 497
 498   node->count = ENTRY_BLOCK_PTR->count;
 499
 500   FOR_EACH_BB (bb)
 501     {
 502       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 503         {
 504           gimple stmt = gsi_stmt (gsi);
 505
 506           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 507                                          mark_store, mark_address);
 508
 509         }
 510       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 511         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 512                                        mark_load, mark_store, mark_address);
 513     }
 514   record_eh_tables (node, cfun);
 515 }
 516
 517 struct gimple_opt_pass pass_rebuild_cgraph_edges =
 518 {
 519  {
 520   GIMPLE_PASS,
 521   "*rebuild_cgraph_edges",              /* name */
 522   NULL,                                 /* gate */
 523   rebuild_cgraph_edges,                 /* execute */
 524   NULL,                                 /* sub */
 525   NULL,                                 /* next */
 526   0,                                    /* static_pass_number */
 527   TV_CGRAPH,                            /* tv_id */
 528   PROP_cfg,                             /* properties_required */
 529   0,                                    /* properties_provided */
 530   0,                                    /* properties_destroyed */
 531   0,                                    /* todo_flags_start */
 532   0,                                    /* todo_flags_finish */
 533  }
 534 };
 535
 536
 537 static unsigned int
 538 remove_cgraph_callee_edges (void)
 539 {
 540   cgraph_node_remove_callees (cgraph_get_node (current_function_decl));
 541   return 0;
 542 }
 543
 544 struct gimple_opt_pass pass_remove_cgraph_callee_edges =
 545 {
 546  {
 547   GIMPLE_PASS,
 548   "*remove_cgraph_callee_edges",                /* name */
 549   NULL,                                 /* gate */
 550   remove_cgraph_callee_edges,           /* execute */
 551   NULL,                                 /* sub */
 552   NULL,                                 /* next */
 553   0,                                    /* static_pass_number */
 554   TV_NONE,                              /* tv_id */
 555   0,                                    /* properties_required */
 556   0,                                    /* properties_provided */
 557   0,                                    /* properties_destroyed */
 558   0,                                    /* todo_flags_start */
 559   0,                                    /* todo_flags_finish */
 560  }
 561 };