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