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