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   t = canonicalize_constructor_val (t);
  57   if (!t)
  58     t = *tp;
  59   else if (t != *tp)
  60     *tp = t;
  61
  62   switch (TREE_CODE (t))
  63     {
  64     case VAR_DECL:
  65     case FUNCTION_DECL:
  66       gcc_unreachable ();
  67       break;
  68
  69     case FDESC_EXPR:
  70     case ADDR_EXPR:
  71       /* Record dereferences to the functions.  This makes the
  72          functions reachable unconditionally.  */
  73       decl = get_base_var (*tp);
  74       if (TREE_CODE (decl) == FUNCTION_DECL)
  75         {
  76           if (!ctx->only_vars)
  77           cgraph_mark_address_taken_node (cgraph_node (decl));
  78           ipa_record_reference (NULL, ctx->varpool_node,
  79                                 cgraph_node (decl), NULL,
  80                                 IPA_REF_ADDR, NULL);
  81         }
  82
  83       if (TREE_CODE (decl) == VAR_DECL)
  84         {
  85           struct varpool_node *vnode = varpool_node (decl);
  86           if (lang_hooks.callgraph.analyze_expr)
  87             lang_hooks.callgraph.analyze_expr (&decl, walk_subtrees);
  88           varpool_mark_needed_node (vnode);
  89           if (vnode->alias && vnode->extra_name)
  90             vnode = vnode->extra_name;
  91           ipa_record_reference (NULL, ctx->varpool_node,
  92                                 NULL, vnode,
  93                                 IPA_REF_ADDR, NULL);
  94         }
  95       *walk_subtrees = 0;
  96       break;
  97
  98     default:
  99       /* Save some cycles by not walking types and declaration as we
 100          won't find anything useful there anyway.  */
 101       if (IS_TYPE_OR_DECL_P (*tp))
 102         {
 103           *walk_subtrees = 0;
 104           break;
 105         }
 106
 107       if ((unsigned int) TREE_CODE (t) >= LAST_AND_UNUSED_TREE_CODE)
 108         return lang_hooks.callgraph.analyze_expr (tp, walk_subtrees);
 109       break;
 110     }
 111
 112   return NULL_TREE;
 113 }
 114
 115 /* Record references to typeinfos in the type list LIST.  */
 116
 117 static void
 118 record_type_list (struct cgraph_node *node, tree list)
 119 {
 120   for (; list; list = TREE_CHAIN (list))
 121     {
 122       tree type = TREE_VALUE (list);
 123
 124       if (TYPE_P (type))
 125         type = lookup_type_for_runtime (type);
 126       STRIP_NOPS (type);
 127       if (TREE_CODE (type) == ADDR_EXPR)
 128         {
 129           type = TREE_OPERAND (type, 0);
 130           if (TREE_CODE (type) == VAR_DECL)
 131             {
 132               struct varpool_node *vnode = varpool_node (type);
 133               varpool_mark_needed_node (vnode);
 134               ipa_record_reference (node, NULL,
 135                                     NULL, vnode,
 136                                     IPA_REF_ADDR, NULL);
 137             }
 138         }
 139     }
 140 }
 141
 142 /* Record all references we will introduce by producing EH tables
 143    for NODE.  */
 144
 145 static void
 146 record_eh_tables (struct cgraph_node *node, struct function *fun)
 147 {
 148   eh_region i;
 149
 150   if (DECL_FUNCTION_PERSONALITY (node->decl))
 151     ipa_record_reference (node, NULL,
 152                           cgraph_node (DECL_FUNCTION_PERSONALITY (node->decl)),
 153                           NULL, IPA_REF_ADDR, NULL);
 154
 155   i = fun->eh->region_tree;
 156   if (!i)
 157     return;
 158
 159   while (1)
 160     {
 161       switch (i->type)
 162         {
 163         case ERT_CLEANUP:
 164         case ERT_MUST_NOT_THROW:
 165           break;
 166
 167         case ERT_TRY:
 168           {
 169             eh_catch c;
 170             for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
 171               record_type_list (node, c->type_list);
 172           }
 173           break;
 174
 175         case ERT_ALLOWED_EXCEPTIONS:
 176           record_type_list (node, i->u.allowed.type_list);
 177           break;
 178         }
 179       /* If there are sub-regions, process them.  */
 180       if (i->inner)
 181         i = i->inner;
 182       /* If there are peers, process them.  */
 183       else if (i->next_peer)
 184         i = i->next_peer;
 185       /* Otherwise, step back up the tree to the next peer.  */
 186       else
 187         {
 188           do
 189             {
 190               i = i->outer;
 191               if (i == NULL)
 192                 return;
 193             }
 194           while (i->next_peer == NULL);
 195           i = i->next_peer;
 196         }
 197     }
 198 }
 199
 200 /* Reset inlining information of all incoming call edges of NODE.  */
 201
 202 void
 203 reset_inline_failed (struct cgraph_node *node)
 204 {
 205   struct cgraph_edge *e;
 206
 207   for (e = node->callers; e; e = e->next_caller)
 208     {
 209       e->callee->global.inlined_to = NULL;
 210       if (!node->analyzed)
 211         e->inline_failed = CIF_BODY_NOT_AVAILABLE;
 212       else if (node->local.redefined_extern_inline)
 213         e->inline_failed = CIF_REDEFINED_EXTERN_INLINE;
 214       else if (!node->local.inlinable)
 215         e->inline_failed = CIF_FUNCTION_NOT_INLINABLE;
 216       else if (e->call_stmt_cannot_inline_p)
 217         e->inline_failed = CIF_MISMATCHED_ARGUMENTS;
 218       else
 219         e->inline_failed = CIF_FUNCTION_NOT_CONSIDERED;
 220     }
 221 }
 222
 223 /* Computes the frequency of the call statement so that it can be stored in
 224    cgraph_edge.  BB is the basic block of the call statement.  */
 225 int
 226 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 227 {
 228   int entry_freq = ENTRY_BLOCK_PTR_FOR_FUNCTION
 229                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 230   int freq = bb->frequency;
 231
 232   if (profile_status_for_function (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 233     return CGRAPH_FREQ_BASE;
 234
 235   if (!entry_freq)
 236     entry_freq = 1, freq++;
 237
 238   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 239   if (freq > CGRAPH_FREQ_MAX)
 240     freq = CGRAPH_FREQ_MAX;
 241
 242   return freq;
 243 }
 244
 245 /* Mark address taken in STMT.  */
 246
 247 static bool
 248 mark_address (gimple stmt, tree addr, void *data)
 249 {
 250   addr = get_base_address (addr);
 251   if (TREE_CODE (addr) == FUNCTION_DECL)
 252     {
 253       struct cgraph_node *node = cgraph_node (addr);
 254       cgraph_mark_address_taken_node (node);
 255       ipa_record_reference ((struct cgraph_node *)data, NULL,
 256                             node, NULL,
 257                             IPA_REF_ADDR, stmt);
 258     }
 259   else if (addr && TREE_CODE (addr) == VAR_DECL
 260            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 261     {
 262       struct varpool_node *vnode = varpool_node (addr);
 263       int walk_subtrees;
 264
 265       if (lang_hooks.callgraph.analyze_expr)
 266         lang_hooks.callgraph.analyze_expr (&addr, &walk_subtrees);
 267       varpool_mark_needed_node (vnode);
 268       if (vnode->alias && vnode->extra_name)
 269         vnode = vnode->extra_name;
 270       ipa_record_reference ((struct cgraph_node *)data, NULL,
 271                             NULL, vnode,
 272                             IPA_REF_ADDR, stmt);
 273     }
 274
 275   return false;
 276 }
 277
 278 /* Mark load of T.  */
 279
 280 static bool
 281 mark_load (gimple stmt, tree t, void *data)
 282 {
 283   t = get_base_address (t);
 284   if (t && TREE_CODE (t) == FUNCTION_DECL)
 285     {
 286       /* ??? This can happen on platforms with descriptors when these are
 287          directly manipulated in the code.  Pretend that it's an address.  */
 288       struct cgraph_node *node = cgraph_node (t);
 289       cgraph_mark_address_taken_node (node);
 290       ipa_record_reference ((struct cgraph_node *)data, NULL,
 291                             node, NULL,
 292                             IPA_REF_ADDR, stmt);
 293     }
 294   else if (t && TREE_CODE (t) == VAR_DECL
 295            && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 296     {
 297       struct varpool_node *vnode = varpool_node (t);
 298       int walk_subtrees;
 299
 300       if (lang_hooks.callgraph.analyze_expr)
 301         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 302       varpool_mark_needed_node (vnode);
 303       if (vnode->alias && vnode->extra_name)
 304         vnode = vnode->extra_name;
 305       ipa_record_reference ((struct cgraph_node *)data, NULL,
 306                             NULL, vnode,
 307                             IPA_REF_LOAD, stmt);
 308     }
 309   return false;
 310 }
 311
 312 /* Mark store of T.  */
 313
 314 static bool
 315 mark_store (gimple stmt, tree t, void *data)
 316 {
 317   t = get_base_address (t);
 318   if (t && TREE_CODE (t) == VAR_DECL
 319       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 320     {
 321       struct varpool_node *vnode = varpool_node (t);
 322       int walk_subtrees;
 323
 324       if (lang_hooks.callgraph.analyze_expr)
 325         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 326       varpool_mark_needed_node (vnode);
 327       if (vnode->alias && vnode->extra_name)
 328         vnode = vnode->extra_name;
 329       ipa_record_reference ((struct cgraph_node *)data, NULL,
 330                             NULL, vnode,
 331                             IPA_REF_STORE, stmt);
 332      }
 333   return false;
 334 }
 335
 336 /* Create cgraph edges for function calls.
 337    Also look for functions and variables having addresses taken.  */
 338
 339 static unsigned int
 340 build_cgraph_edges (void)
 341 {
 342   basic_block bb;
 343   struct cgraph_node *node = cgraph_node (current_function_decl);
 344   struct pointer_set_t *visited_nodes = pointer_set_create ();
 345   gimple_stmt_iterator gsi;
 346   tree decl;
 347   unsigned ix;
 348
 349   /* Create the callgraph edges and record the nodes referenced by the function.
 350      body.  */
 351   FOR_EACH_BB (bb)
 352     {
 353       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 354         {
 355           gimple stmt = gsi_stmt (gsi);
 356           tree decl;
 357
 358           if (is_gimple_call (stmt))
 359             {
 360               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 361                                                          bb);
 362               decl = gimple_call_fndecl (stmt);
 363               if (decl)
 364                 cgraph_create_edge (node, cgraph_node (decl), stmt,
 365                                     bb->count, freq,
 366                                     bb->loop_depth);
 367               else
 368                 cgraph_create_indirect_edge (node, stmt,
 369                                              gimple_call_flags (stmt),
 370                                              bb->count, freq,
 371                                              bb->loop_depth);
 372             }
 373           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 374                                          mark_store, mark_address);
 375           if (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
 376               && gimple_omp_parallel_child_fn (stmt))
 377             {
 378               tree fn = gimple_omp_parallel_child_fn (stmt);
 379               ipa_record_reference (node, NULL, cgraph_node (fn),
 380                                     NULL, IPA_REF_ADDR, stmt);
 381             }
 382           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 383             {
 384               tree fn = gimple_omp_task_child_fn (stmt);
 385               if (fn)
 386                 ipa_record_reference (node, NULL, cgraph_node (fn),
 387                                       NULL, IPA_REF_ADDR, stmt);
 388               fn = gimple_omp_task_copy_fn (stmt);
 389               if (fn)
 390                 ipa_record_reference (node, NULL, cgraph_node (fn),
 391                                       NULL, IPA_REF_ADDR, stmt);
 392             }
 393         }
 394       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 395         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 396                                        mark_load, mark_store, mark_address);
 397    }
 398
 399   /* Look for initializers of constant variables and private statics.  */
 400   FOR_EACH_LOCAL_DECL (cfun, ix, decl)
 401     if (TREE_CODE (decl) == VAR_DECL
 402         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl)))
 403       varpool_finalize_decl (decl);
 404   record_eh_tables (node, cfun);
 405
 406   pointer_set_destroy (visited_nodes);
 407   return 0;
 408 }
 409
 410 struct gimple_opt_pass pass_build_cgraph_edges =
 411 {
 412  {
 413   GIMPLE_PASS,
 414   "*build_cgraph_edges",                        /* name */
 415   NULL,                                 /* gate */
 416   build_cgraph_edges,                   /* execute */
 417   NULL,                                 /* sub */
 418   NULL,                                 /* next */
 419   0,                                    /* static_pass_number */
 420   TV_NONE,                              /* tv_id */
 421   PROP_cfg,                             /* properties_required */
 422   0,                                    /* properties_provided */
 423   0,                                    /* properties_destroyed */
 424   0,                                    /* todo_flags_start */
 425   0                                     /* todo_flags_finish */
 426  }
 427 };
 428
 429 /* Record references to functions and other variables present in the
 430    initial value of DECL, a variable.
 431    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 432
 433 void
 434 record_references_in_initializer (tree decl, bool only_vars)
 435 {
 436   struct pointer_set_t *visited_nodes = pointer_set_create ();
 437   struct varpool_node *node = varpool_node (decl);
 438   struct record_reference_ctx ctx = {false, NULL};
 439
 440   ctx.varpool_node = node;
 441   ctx.only_vars = only_vars;
 442   walk_tree (&DECL_INITIAL (decl), record_reference,
 443              &ctx, visited_nodes);
 444   pointer_set_destroy (visited_nodes);
 445 }
 446
 447 /* Rebuild cgraph edges for current function node.  This needs to be run after
 448    passes that don't update the cgraph.  */
 449
 450 unsigned int
 451 rebuild_cgraph_edges (void)
 452 {
 453   basic_block bb;
 454   struct cgraph_node *node = cgraph_node (current_function_decl);
 455   gimple_stmt_iterator gsi;
 456
 457   cgraph_node_remove_callees (node);
 458   ipa_remove_all_references (&node->ref_list);
 459
 460   node->count = ENTRY_BLOCK_PTR->count;
 461
 462   FOR_EACH_BB (bb)
 463     {
 464       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 465         {
 466           gimple stmt = gsi_stmt (gsi);
 467           tree decl;
 468
 469           if (is_gimple_call (stmt))
 470             {
 471               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 472                                                          bb);
 473               decl = gimple_call_fndecl (stmt);
 474               if (decl)
 475                 cgraph_create_edge (node, cgraph_node (decl), stmt,
 476                                     bb->count, freq,
 477                                     bb->loop_depth);
 478               else
 479                 cgraph_create_indirect_edge (node, stmt,
 480                                              gimple_call_flags (stmt),
 481                                              bb->count, freq,
 482                                              bb->loop_depth);
 483             }
 484           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 485                                          mark_store, mark_address);
 486
 487         }
 488       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 489         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 490                                        mark_load, mark_store, mark_address);
 491     }
 492   record_eh_tables (node, cfun);
 493   gcc_assert (!node->global.inlined_to);
 494
 495   return 0;
 496 }
 497
 498 /* Rebuild cgraph edges for current function node.  This needs to be run after
 499    passes that don't update the cgraph.  */
 500
 501 void
 502 cgraph_rebuild_references (void)
 503 {
 504   basic_block bb;
 505   struct cgraph_node *node = cgraph_node (current_function_decl);
 506   gimple_stmt_iterator gsi;
 507
 508   ipa_remove_all_references (&node->ref_list);
 509
 510   node->count = ENTRY_BLOCK_PTR->count;
 511
 512   FOR_EACH_BB (bb)
 513     {
 514       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 515         {
 516           gimple stmt = gsi_stmt (gsi);
 517
 518           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 519                                          mark_store, mark_address);
 520
 521         }
 522       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 523         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 524                                        mark_load, mark_store, mark_address);
 525     }
 526   record_eh_tables (node, cfun);
 527 }
 528
 529 struct gimple_opt_pass pass_rebuild_cgraph_edges =
 530 {
 531  {
 532   GIMPLE_PASS,
 533   "*rebuild_cgraph_edges",              /* name */
 534   NULL,                                 /* gate */
 535   rebuild_cgraph_edges,                 /* execute */
 536   NULL,                                 /* sub */
 537   NULL,                                 /* next */
 538   0,                                    /* static_pass_number */
 539   TV_CGRAPH,                            /* tv_id */
 540   PROP_cfg,                             /* properties_required */
 541   0,                                    /* properties_provided */
 542   0,                                    /* properties_destroyed */
 543   0,                                    /* todo_flags_start */
 544   0,                                    /* todo_flags_finish */
 545  }
 546 };
 547
 548
 549 static unsigned int
 550 remove_cgraph_callee_edges (void)
 551 {
 552   cgraph_node_remove_callees (cgraph_node (current_function_decl));
 553   return 0;
 554 }
 555
 556 struct gimple_opt_pass pass_remove_cgraph_callee_edges =
 557 {
 558  {
 559   GIMPLE_PASS,
 560   "*remove_cgraph_callee_edges",                /* name */
 561   NULL,                                 /* gate */
 562   remove_cgraph_callee_edges,           /* execute */
 563   NULL,                                 /* sub */
 564   NULL,                                 /* next */
 565   0,                                    /* static_pass_number */
 566   TV_NONE,                              /* tv_id */
 567   0,                                    /* properties_required */
 568   0,                                    /* properties_provided */
 569   0,                                    /* properties_destroyed */
 570   0,                                    /* todo_flags_start */
 571   0,                                    /* todo_flags_finish */
 572  }
 573 };