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           ipa_record_reference (NULL, ctx->varpool_node,
  91                                 NULL, 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               varpool_mark_needed_node (vnode);
 133               ipa_record_reference (node, NULL,
 134                                     NULL, vnode,
 135                                     IPA_REF_ADDR, NULL);
 136             }
 137         }
 138     }
 139 }
 140
 141 /* Record all references we will introduce by producing EH tables
 142    for NODE.  */
 143
 144 static void
 145 record_eh_tables (struct cgraph_node *node, struct function *fun)
 146 {
 147   eh_region i;
 148
 149   if (DECL_FUNCTION_PERSONALITY (node->decl))
 150     {
 151       struct cgraph_node *per_node;
 152
 153       per_node = cgraph_get_create_node (DECL_FUNCTION_PERSONALITY (node->decl));
 154       ipa_record_reference (node, NULL, per_node, NULL, IPA_REF_ADDR, NULL);
 155       cgraph_mark_address_taken_node (per_node);
 156     }
 157
 158   i = fun->eh->region_tree;
 159   if (!i)
 160     return;
 161
 162   while (1)
 163     {
 164       switch (i->type)
 165         {
 166         case ERT_CLEANUP:
 167         case ERT_MUST_NOT_THROW:
 168           break;
 169
 170         case ERT_TRY:
 171           {
 172             eh_catch c;
 173             for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
 174               record_type_list (node, c->type_list);
 175           }
 176           break;
 177
 178         case ERT_ALLOWED_EXCEPTIONS:
 179           record_type_list (node, i->u.allowed.type_list);
 180           break;
 181         }
 182       /* If there are sub-regions, process them.  */
 183       if (i->inner)
 184         i = i->inner;
 185       /* If there are peers, process them.  */
 186       else if (i->next_peer)
 187         i = i->next_peer;
 188       /* Otherwise, step back up the tree to the next peer.  */
 189       else
 190         {
 191           do
 192             {
 193               i = i->outer;
 194               if (i == NULL)
 195                 return;
 196             }
 197           while (i->next_peer == NULL);
 198           i = i->next_peer;
 199         }
 200     }
 201 }
 202
 203 /* Reset inlining information of all incoming call edges of NODE.  */
 204
 205 void
 206 reset_inline_failed (struct cgraph_node *node)
 207 {
 208   struct cgraph_edge *e;
 209
 210   for (e = node->callers; e; e = e->next_caller)
 211     {
 212       e->callee->global.inlined_to = NULL;
 213       initialize_inline_failed (e);
 214     }
 215 }
 216
 217 /* Computes the frequency of the call statement so that it can be stored in
 218    cgraph_edge.  BB is the basic block of the call statement.  */
 219 int
 220 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 221 {
 222   int entry_freq = ENTRY_BLOCK_PTR_FOR_FUNCTION
 223                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 224   int freq = bb->frequency;
 225
 226   if (profile_status_for_function (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 227     return CGRAPH_FREQ_BASE;
 228
 229   if (!entry_freq)
 230     entry_freq = 1, freq++;
 231
 232   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 233   if (freq > CGRAPH_FREQ_MAX)
 234     freq = CGRAPH_FREQ_MAX;
 235
 236   return freq;
 237 }
 238
 239 /* Mark address taken in STMT.  */
 240
 241 static bool
 242 mark_address (gimple stmt, tree addr, void *data)
 243 {
 244   addr = get_base_address (addr);
 245   if (TREE_CODE (addr) == FUNCTION_DECL)
 246     {
 247       struct cgraph_node *node = cgraph_get_create_node (addr);
 248       cgraph_mark_address_taken_node (node);
 249       ipa_record_reference ((struct cgraph_node *)data, NULL,
 250                             node, NULL,
 251                             IPA_REF_ADDR, stmt);
 252     }
 253   else if (addr && TREE_CODE (addr) == VAR_DECL
 254            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 255     {
 256       struct varpool_node *vnode = varpool_node (addr);
 257       int walk_subtrees;
 258
 259       if (lang_hooks.callgraph.analyze_expr)
 260         lang_hooks.callgraph.analyze_expr (&addr, &walk_subtrees);
 261       varpool_mark_needed_node (vnode);
 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       ipa_record_reference ((struct cgraph_node *)data, NULL,
 296                             NULL, vnode,
 297                             IPA_REF_LOAD, stmt);
 298     }
 299   return false;
 300 }
 301
 302 /* Mark store of T.  */
 303
 304 static bool
 305 mark_store (gimple stmt, tree t, void *data)
 306 {
 307   t = get_base_address (t);
 308   if (t && TREE_CODE (t) == VAR_DECL
 309       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 310     {
 311       struct varpool_node *vnode = varpool_node (t);
 312       int walk_subtrees;
 313
 314       if (lang_hooks.callgraph.analyze_expr)
 315         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 316       varpool_mark_needed_node (vnode);
 317       ipa_record_reference ((struct cgraph_node *)data, NULL,
 318                             NULL, vnode,
 319                             IPA_REF_STORE, stmt);
 320      }
 321   return false;
 322 }
 323
 324 /* Create cgraph edges for function calls.
 325    Also look for functions and variables having addresses taken.  */
 326
 327 static unsigned int
 328 build_cgraph_edges (void)
 329 {
 330   basic_block bb;
 331   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 332   struct pointer_set_t *visited_nodes = pointer_set_create ();
 333   gimple_stmt_iterator gsi;
 334   tree decl;
 335   unsigned ix;
 336
 337   /* Create the callgraph edges and record the nodes referenced by the function.
 338      body.  */
 339   FOR_EACH_BB (bb)
 340     {
 341       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 342         {
 343           gimple stmt = gsi_stmt (gsi);
 344           tree decl;
 345
 346           if (is_gimple_call (stmt))
 347             {
 348               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 349                                                          bb);
 350               decl = gimple_call_fndecl (stmt);
 351               if (decl)
 352                 cgraph_create_edge (node, cgraph_get_create_node (decl),
 353                                     stmt, bb->count, freq);
 354               else
 355                 cgraph_create_indirect_edge (node, stmt,
 356                                              gimple_call_flags (stmt),
 357                                              bb->count, freq);
 358             }
 359           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 360                                          mark_store, mark_address);
 361           if (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
 362               && gimple_omp_parallel_child_fn (stmt))
 363             {
 364               tree fn = gimple_omp_parallel_child_fn (stmt);
 365               ipa_record_reference (node, NULL, cgraph_get_create_node (fn),
 366                                     NULL, IPA_REF_ADDR, stmt);
 367             }
 368           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 369             {
 370               tree fn = gimple_omp_task_child_fn (stmt);
 371               if (fn)
 372                 ipa_record_reference (node, NULL, cgraph_get_create_node (fn),
 373                                       NULL, IPA_REF_ADDR, stmt);
 374               fn = gimple_omp_task_copy_fn (stmt);
 375               if (fn)
 376                 ipa_record_reference (node, NULL, cgraph_get_create_node (fn),
 377                                       NULL, IPA_REF_ADDR, stmt);
 378             }
 379         }
 380       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 381         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 382                                        mark_load, mark_store, mark_address);
 383    }
 384
 385   /* Look for initializers of constant variables and private statics.  */
 386   FOR_EACH_LOCAL_DECL (cfun, ix, decl)
 387     if (TREE_CODE (decl) == VAR_DECL
 388         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl)))
 389       varpool_finalize_decl (decl);
 390   record_eh_tables (node, cfun);
 391
 392   pointer_set_destroy (visited_nodes);
 393   return 0;
 394 }
 395
 396 struct gimple_opt_pass pass_build_cgraph_edges =
 397 {
 398  {
 399   GIMPLE_PASS,
 400   "*build_cgraph_edges",                        /* name */
 401   NULL,                                 /* gate */
 402   build_cgraph_edges,                   /* execute */
 403   NULL,                                 /* sub */
 404   NULL,                                 /* next */
 405   0,                                    /* static_pass_number */
 406   TV_NONE,                              /* tv_id */
 407   PROP_cfg,                             /* properties_required */
 408   0,                                    /* properties_provided */
 409   0,                                    /* properties_destroyed */
 410   0,                                    /* todo_flags_start */
 411   0                                     /* todo_flags_finish */
 412  }
 413 };
 414
 415 /* Record references to functions and other variables present in the
 416    initial value of DECL, a variable.
 417    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 418
 419 void
 420 record_references_in_initializer (tree decl, bool only_vars)
 421 {
 422   struct pointer_set_t *visited_nodes = pointer_set_create ();
 423   struct varpool_node *node = varpool_node (decl);
 424   struct record_reference_ctx ctx = {false, NULL};
 425
 426   ctx.varpool_node = node;
 427   ctx.only_vars = only_vars;
 428   walk_tree (&DECL_INITIAL (decl), record_reference,
 429              &ctx, visited_nodes);
 430   pointer_set_destroy (visited_nodes);
 431 }
 432
 433 /* Rebuild cgraph edges for current function node.  This needs to be run after
 434    passes that don't update the cgraph.  */
 435
 436 unsigned int
 437 rebuild_cgraph_edges (void)
 438 {
 439   basic_block bb;
 440   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 441   gimple_stmt_iterator gsi;
 442
 443   cgraph_node_remove_callees (node);
 444   ipa_remove_all_references (&node->ref_list);
 445
 446   node->count = ENTRY_BLOCK_PTR->count;
 447
 448   FOR_EACH_BB (bb)
 449     {
 450       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 451         {
 452           gimple stmt = gsi_stmt (gsi);
 453           tree decl;
 454
 455           if (is_gimple_call (stmt))
 456             {
 457               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 458                                                          bb);
 459               decl = gimple_call_fndecl (stmt);
 460               if (decl)
 461                 cgraph_create_edge (node, cgraph_get_create_node (decl), stmt,
 462                                     bb->count, freq);
 463               else
 464                 cgraph_create_indirect_edge (node, stmt,
 465                                              gimple_call_flags (stmt),
 466                                              bb->count, freq);
 467             }
 468           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 469                                          mark_store, mark_address);
 470
 471         }
 472       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 473         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 474                                        mark_load, mark_store, mark_address);
 475     }
 476   record_eh_tables (node, cfun);
 477   gcc_assert (!node->global.inlined_to);
 478
 479   return 0;
 480 }
 481
 482 /* Rebuild cgraph edges for current function node.  This needs to be run after
 483    passes that don't update the cgraph.  */
 484
 485 void
 486 cgraph_rebuild_references (void)
 487 {
 488   basic_block bb;
 489   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 490   gimple_stmt_iterator gsi;
 491
 492   ipa_remove_all_references (&node->ref_list);
 493
 494   node->count = ENTRY_BLOCK_PTR->count;
 495
 496   FOR_EACH_BB (bb)
 497     {
 498       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 499         {
 500           gimple stmt = gsi_stmt (gsi);
 501
 502           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 503                                          mark_store, mark_address);
 504
 505         }
 506       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 507         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 508                                        mark_load, mark_store, mark_address);
 509     }
 510   record_eh_tables (node, cfun);
 511 }
 512
 513 struct gimple_opt_pass pass_rebuild_cgraph_edges =
 514 {
 515  {
 516   GIMPLE_PASS,
 517   "*rebuild_cgraph_edges",              /* name */
 518   NULL,                                 /* gate */
 519   rebuild_cgraph_edges,                 /* execute */
 520   NULL,                                 /* sub */
 521   NULL,                                 /* next */
 522   0,                                    /* static_pass_number */
 523   TV_CGRAPH,                            /* tv_id */
 524   PROP_cfg,                             /* properties_required */
 525   0,                                    /* properties_provided */
 526   0,                                    /* properties_destroyed */
 527   0,                                    /* todo_flags_start */
 528   0,                                    /* todo_flags_finish */
 529  }
 530 };
 531
 532
 533 static unsigned int
 534 remove_cgraph_callee_edges (void)
 535 {
 536   cgraph_node_remove_callees (cgraph_get_node (current_function_decl));
 537   return 0;
 538 }
 539
 540 struct gimple_opt_pass pass_remove_cgraph_callee_edges =
 541 {
 542  {
 543   GIMPLE_PASS,
 544   "*remove_cgraph_callee_edges",                /* name */
 545   NULL,                                 /* gate */
 546   remove_cgraph_callee_edges,           /* execute */
 547   NULL,                                 /* sub */
 548   NULL,                                 /* next */
 549   0,                                    /* static_pass_number */
 550   TV_NONE,                              /* tv_id */
 551   0,                                    /* properties_required */
 552   0,                                    /* properties_provided */
 553   0,                                    /* properties_destroyed */
 554   0,                                    /* todo_flags_start */
 555   0,                                    /* todo_flags_finish */
 556  }
 557 };