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 ((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           if (lang_hooks.callgraph.analyze_expr)
  89             lang_hooks.callgraph.analyze_expr (&decl, walk_subtrees);
  90           ipa_record_reference ((symtab_node)ctx->varpool_node,
  91                                 (symtab_node)vnode,
  92                                 IPA_REF_ADDR, NULL);
  93         }
  94       *walk_subtrees = 0;
  95       break;
  96
  97     default:
  98       /* Save some cycles by not walking types and declaration as we
  99          won't find anything useful there anyway.  */
 100       if (IS_TYPE_OR_DECL_P (*tp))
 101         {
 102           *walk_subtrees = 0;
 103           break;
 104         }
 105
 106       if ((unsigned int) TREE_CODE (t) >= LAST_AND_UNUSED_TREE_CODE)
 107         return lang_hooks.callgraph.analyze_expr (tp, walk_subtrees);
 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               struct varpool_node *vnode = varpool_node (type);
 132               ipa_record_reference ((symtab_node)node,
 133                                     (symtab_node)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->symbol.decl))
 149     {
 150       struct cgraph_node *per_node;
 151
 152       per_node = cgraph_get_create_node (DECL_FUNCTION_PERSONALITY (node->symbol.decl));
 153       ipa_record_reference ((symtab_node)node, (symtab_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_FUNCTION
 208                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 209   int freq = bb->frequency;
 210
 211   if (profile_status_for_function (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, 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                             (symtab_node)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       struct varpool_node *vnode = varpool_node (addr);
 242       int walk_subtrees;
 243
 244       if (lang_hooks.callgraph.analyze_expr)
 245         lang_hooks.callgraph.analyze_expr (&addr, &walk_subtrees);
 246       ipa_record_reference ((symtab_node)data,
 247                             (symtab_node)vnode,
 248                             IPA_REF_ADDR, stmt);
 249     }
 250
 251   return false;
 252 }
 253
 254 /* Mark load of T.  */
 255
 256 static bool
 257 mark_load (gimple stmt, tree t, void *data)
 258 {
 259   t = get_base_address (t);
 260   if (t && TREE_CODE (t) == FUNCTION_DECL)
 261     {
 262       /* ??? This can happen on platforms with descriptors when these are
 263          directly manipulated in the code.  Pretend that it's an address.  */
 264       struct cgraph_node *node = cgraph_get_create_node (t);
 265       cgraph_mark_address_taken_node (node);
 266       ipa_record_reference ((symtab_node)data,
 267                             (symtab_node)node,
 268                             IPA_REF_ADDR, stmt);
 269     }
 270   else if (t && TREE_CODE (t) == VAR_DECL
 271            && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 272     {
 273       struct varpool_node *vnode = varpool_node (t);
 274       int walk_subtrees;
 275
 276       if (lang_hooks.callgraph.analyze_expr)
 277         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 278       ipa_record_reference ((symtab_node)data,
 279                             (symtab_node)vnode,
 280                             IPA_REF_LOAD, stmt);
 281     }
 282   return false;
 283 }
 284
 285 /* Mark store of T.  */
 286
 287 static bool
 288 mark_store (gimple stmt, tree t, void *data)
 289 {
 290   t = get_base_address (t);
 291   if (t && TREE_CODE (t) == VAR_DECL
 292       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 293     {
 294       struct varpool_node *vnode = varpool_node (t);
 295       int walk_subtrees;
 296
 297       if (lang_hooks.callgraph.analyze_expr)
 298         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 299       ipa_record_reference ((symtab_node)data,
 300                             (symtab_node)vnode,
 301                             IPA_REF_STORE, stmt);
 302      }
 303   return false;
 304 }
 305
 306 /* Create cgraph edges for function calls.
 307    Also look for functions and variables having addresses taken.  */
 308
 309 static unsigned int
 310 build_cgraph_edges (void)
 311 {
 312   basic_block bb;
 313   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 314   struct pointer_set_t *visited_nodes = pointer_set_create ();
 315   gimple_stmt_iterator gsi;
 316   tree decl;
 317   unsigned ix;
 318
 319   /* Create the callgraph edges and record the nodes referenced by the function.
 320      body.  */
 321   FOR_EACH_BB (bb)
 322     {
 323       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 324         {
 325           gimple stmt = gsi_stmt (gsi);
 326           tree decl;
 327
 328           if (is_gimple_call (stmt))
 329             {
 330               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 331                                                          bb);
 332               decl = gimple_call_fndecl (stmt);
 333               if (decl)
 334                 cgraph_create_edge (node, cgraph_get_create_node (decl),
 335                                     stmt, bb->count, freq);
 336               else
 337                 cgraph_create_indirect_edge (node, stmt,
 338                                              gimple_call_flags (stmt),
 339                                              bb->count, freq);
 340             }
 341           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 342                                          mark_store, mark_address);
 343           if (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
 344               && gimple_omp_parallel_child_fn (stmt))
 345             {
 346               tree fn = gimple_omp_parallel_child_fn (stmt);
 347               ipa_record_reference ((symtab_node)node,
 348                                     (symtab_node)cgraph_get_create_node (fn),
 349                                     IPA_REF_ADDR, stmt);
 350             }
 351           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 352             {
 353               tree fn = gimple_omp_task_child_fn (stmt);
 354               if (fn)
 355                 ipa_record_reference ((symtab_node)node,
 356                                       (symtab_node) cgraph_get_create_node (fn),
 357                                       IPA_REF_ADDR, stmt);
 358               fn = gimple_omp_task_copy_fn (stmt);
 359               if (fn)
 360                 ipa_record_reference ((symtab_node)node,
 361                                       (symtab_node)cgraph_get_create_node (fn),
 362                                       IPA_REF_ADDR, stmt);
 363             }
 364         }
 365       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 366         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 367                                        mark_load, mark_store, mark_address);
 368    }
 369
 370   /* Look for initializers of constant variables and private statics.  */
 371   FOR_EACH_LOCAL_DECL (cfun, ix, decl)
 372     if (TREE_CODE (decl) == VAR_DECL
 373         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl)))
 374       varpool_finalize_decl (decl);
 375   record_eh_tables (node, cfun);
 376
 377   pointer_set_destroy (visited_nodes);
 378   return 0;
 379 }
 380
 381 struct gimple_opt_pass pass_build_cgraph_edges =
 382 {
 383  {
 384   GIMPLE_PASS,
 385   "*build_cgraph_edges",                        /* name */
 386   NULL,                                 /* gate */
 387   build_cgraph_edges,                   /* execute */
 388   NULL,                                 /* sub */
 389   NULL,                                 /* next */
 390   0,                                    /* static_pass_number */
 391   TV_NONE,                              /* tv_id */
 392   PROP_cfg,                             /* properties_required */
 393   0,                                    /* properties_provided */
 394   0,                                    /* properties_destroyed */
 395   0,                                    /* todo_flags_start */
 396   0                                     /* todo_flags_finish */
 397  }
 398 };
 399
 400 /* Record references to functions and other variables present in the
 401    initial value of DECL, a variable.
 402    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 403
 404 void
 405 record_references_in_initializer (tree decl, bool only_vars)
 406 {
 407   struct pointer_set_t *visited_nodes = pointer_set_create ();
 408   struct varpool_node *node = varpool_node (decl);
 409   struct record_reference_ctx ctx = {false, NULL};
 410
 411   ctx.varpool_node = node;
 412   ctx.only_vars = only_vars;
 413   walk_tree (&DECL_INITIAL (decl), record_reference,
 414              &ctx, visited_nodes);
 415   pointer_set_destroy (visited_nodes);
 416 }
 417
 418 /* Rebuild cgraph edges for current function node.  This needs to be run after
 419    passes that don't update the cgraph.  */
 420
 421 unsigned int
 422 rebuild_cgraph_edges (void)
 423 {
 424   basic_block bb;
 425   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 426   gimple_stmt_iterator gsi;
 427
 428   cgraph_node_remove_callees (node);
 429   ipa_remove_all_references (&node->symbol.ref_list);
 430
 431   node->count = ENTRY_BLOCK_PTR->count;
 432
 433   FOR_EACH_BB (bb)
 434     {
 435       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 436         {
 437           gimple stmt = gsi_stmt (gsi);
 438           tree decl;
 439
 440           if (is_gimple_call (stmt))
 441             {
 442               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 443                                                          bb);
 444               decl = gimple_call_fndecl (stmt);
 445               if (decl)
 446                 cgraph_create_edge (node, cgraph_get_create_node (decl), stmt,
 447                                     bb->count, freq);
 448               else
 449                 cgraph_create_indirect_edge (node, stmt,
 450                                              gimple_call_flags (stmt),
 451                                              bb->count, freq);
 452             }
 453           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 454                                          mark_store, mark_address);
 455
 456         }
 457       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 458         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 459                                        mark_load, mark_store, mark_address);
 460     }
 461   record_eh_tables (node, cfun);
 462   gcc_assert (!node->global.inlined_to);
 463
 464   return 0;
 465 }
 466
 467 /* Rebuild cgraph edges for current function node.  This needs to be run after
 468    passes that don't update the cgraph.  */
 469
 470 void
 471 cgraph_rebuild_references (void)
 472 {
 473   basic_block bb;
 474   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 475   gimple_stmt_iterator gsi;
 476
 477   ipa_remove_all_references (&node->symbol.ref_list);
 478
 479   node->count = ENTRY_BLOCK_PTR->count;
 480
 481   FOR_EACH_BB (bb)
 482     {
 483       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 484         {
 485           gimple stmt = gsi_stmt (gsi);
 486
 487           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 488                                          mark_store, mark_address);
 489
 490         }
 491       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 492         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 493                                        mark_load, mark_store, mark_address);
 494     }
 495   record_eh_tables (node, cfun);
 496 }
 497
 498 struct gimple_opt_pass pass_rebuild_cgraph_edges =
 499 {
 500  {
 501   GIMPLE_PASS,
 502   "*rebuild_cgraph_edges",              /* name */
 503   NULL,                                 /* gate */
 504   rebuild_cgraph_edges,                 /* execute */
 505   NULL,                                 /* sub */
 506   NULL,                                 /* next */
 507   0,                                    /* static_pass_number */
 508   TV_CGRAPH,                            /* tv_id */
 509   PROP_cfg,                             /* properties_required */
 510   0,                                    /* properties_provided */
 511   0,                                    /* properties_destroyed */
 512   0,                                    /* todo_flags_start */
 513   0,                                    /* todo_flags_finish */
 514  }
 515 };
 516
 517
 518 static unsigned int
 519 remove_cgraph_callee_edges (void)
 520 {
 521   cgraph_node_remove_callees (cgraph_get_node (current_function_decl));
 522   return 0;
 523 }
 524
 525 struct gimple_opt_pass pass_remove_cgraph_callee_edges =
 526 {
 527  {
 528   GIMPLE_PASS,
 529   "*remove_cgraph_callee_edges",                /* name */
 530   NULL,                                 /* gate */
 531   remove_cgraph_callee_edges,           /* execute */
 532   NULL,                                 /* sub */
 533   NULL,                                 /* next */
 534   0,                                    /* static_pass_number */
 535   TV_NONE,                              /* tv_id */
 536   0,                                    /* properties_required */
 537   0,                                    /* properties_provided */
 538   0,                                    /* properties_destroyed */
 539   0,                                    /* todo_flags_start */
 540   0,                                    /* todo_flags_finish */
 541  }
 542 };