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           if (vnode->alias && vnode->extra_name)
  91             vnode = vnode->extra_name;
  92           ipa_record_reference (NULL, ctx->varpool_node,
  93                                 NULL, vnode,
  94                                 IPA_REF_ADDR, NULL);
  95         }
  96       *walk_subtrees = 0;
  97       break;
  98
  99     default:
 100       /* Save some cycles by not walking types and declaration as we
 101          won't find anything useful there anyway.  */
 102       if (IS_TYPE_OR_DECL_P (*tp))
 103         {
 104           *walk_subtrees = 0;
 105           break;
 106         }
 107
 108       if ((unsigned int) TREE_CODE (t) >= LAST_AND_UNUSED_TREE_CODE)
 109         return lang_hooks.callgraph.analyze_expr (tp, walk_subtrees);
 110       break;
 111     }
 112
 113   return NULL_TREE;
 114 }
 115
 116 /* Record references to typeinfos in the type list LIST.  */
 117
 118 static void
 119 record_type_list (struct cgraph_node *node, tree list)
 120 {
 121   for (; list; list = TREE_CHAIN (list))
 122     {
 123       tree type = TREE_VALUE (list);
 124
 125       if (TYPE_P (type))
 126         type = lookup_type_for_runtime (type);
 127       STRIP_NOPS (type);
 128       if (TREE_CODE (type) == ADDR_EXPR)
 129         {
 130           type = TREE_OPERAND (type, 0);
 131           if (TREE_CODE (type) == VAR_DECL)
 132             {
 133               struct varpool_node *vnode = varpool_node (type);
 134               varpool_mark_needed_node (vnode);
 135               ipa_record_reference (node, NULL,
 136                                     NULL, vnode,
 137                                     IPA_REF_ADDR, NULL);
 138             }
 139         }
 140     }
 141 }
 142
 143 /* Record all references we will introduce by producing EH tables
 144    for NODE.  */
 145
 146 static void
 147 record_eh_tables (struct cgraph_node *node, struct function *fun)
 148 {
 149   eh_region i;
 150
 151   if (DECL_FUNCTION_PERSONALITY (node->decl))
 152     {
 153       struct cgraph_node *per_node;
 154
 155       per_node = cgraph_get_create_node (DECL_FUNCTION_PERSONALITY (node->decl));
 156       ipa_record_reference (node, NULL, per_node, NULL, IPA_REF_ADDR, NULL);
 157       cgraph_mark_address_taken_node (per_node);
 158     }
 159
 160   i = fun->eh->region_tree;
 161   if (!i)
 162     return;
 163
 164   while (1)
 165     {
 166       switch (i->type)
 167         {
 168         case ERT_CLEANUP:
 169         case ERT_MUST_NOT_THROW:
 170           break;
 171
 172         case ERT_TRY:
 173           {
 174             eh_catch c;
 175             for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
 176               record_type_list (node, c->type_list);
 177           }
 178           break;
 179
 180         case ERT_ALLOWED_EXCEPTIONS:
 181           record_type_list (node, i->u.allowed.type_list);
 182           break;
 183         }
 184       /* If there are sub-regions, process them.  */
 185       if (i->inner)
 186         i = i->inner;
 187       /* If there are peers, process them.  */
 188       else if (i->next_peer)
 189         i = i->next_peer;
 190       /* Otherwise, step back up the tree to the next peer.  */
 191       else
 192         {
 193           do
 194             {
 195               i = i->outer;
 196               if (i == NULL)
 197                 return;
 198             }
 199           while (i->next_peer == NULL);
 200           i = i->next_peer;
 201         }
 202     }
 203 }
 204
 205 /* Reset inlining information of all incoming call edges of NODE.  */
 206
 207 void
 208 reset_inline_failed (struct cgraph_node *node)
 209 {
 210   struct cgraph_edge *e;
 211
 212   for (e = node->callers; e; e = e->next_caller)
 213     {
 214       e->callee->global.inlined_to = NULL;
 215       initialize_inline_failed (e);
 216     }
 217 }
 218
 219 /* Computes the frequency of the call statement so that it can be stored in
 220    cgraph_edge.  BB is the basic block of the call statement.  */
 221 int
 222 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 223 {
 224   int entry_freq = ENTRY_BLOCK_PTR_FOR_FUNCTION
 225                      (DECL_STRUCT_FUNCTION (decl))->frequency;
 226   int freq = bb->frequency;
 227
 228   if (profile_status_for_function (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
 229     return CGRAPH_FREQ_BASE;
 230
 231   if (!entry_freq)
 232     entry_freq = 1, freq++;
 233
 234   freq = freq * CGRAPH_FREQ_BASE / entry_freq;
 235   if (freq > CGRAPH_FREQ_MAX)
 236     freq = CGRAPH_FREQ_MAX;
 237
 238   return freq;
 239 }
 240
 241 /* Mark address taken in STMT.  */
 242
 243 static bool
 244 mark_address (gimple stmt, tree addr, void *data)
 245 {
 246   addr = get_base_address (addr);
 247   if (TREE_CODE (addr) == FUNCTION_DECL)
 248     {
 249       struct cgraph_node *node = cgraph_get_create_node (addr);
 250       cgraph_mark_address_taken_node (node);
 251       ipa_record_reference ((struct cgraph_node *)data, NULL,
 252                             node, NULL,
 253                             IPA_REF_ADDR, stmt);
 254     }
 255   else if (addr && TREE_CODE (addr) == VAR_DECL
 256            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 257     {
 258       struct varpool_node *vnode = varpool_node (addr);
 259       int walk_subtrees;
 260
 261       if (lang_hooks.callgraph.analyze_expr)
 262         lang_hooks.callgraph.analyze_expr (&addr, &walk_subtrees);
 263       varpool_mark_needed_node (vnode);
 264       if (vnode->alias && vnode->extra_name)
 265         vnode = vnode->extra_name;
 266       ipa_record_reference ((struct cgraph_node *)data, NULL,
 267                             NULL, vnode,
 268                             IPA_REF_ADDR, stmt);
 269     }
 270
 271   return false;
 272 }
 273
 274 /* Mark load of T.  */
 275
 276 static bool
 277 mark_load (gimple stmt, tree t, void *data)
 278 {
 279   t = get_base_address (t);
 280   if (t && TREE_CODE (t) == FUNCTION_DECL)
 281     {
 282       /* ??? This can happen on platforms with descriptors when these are
 283          directly manipulated in the code.  Pretend that it's an address.  */
 284       struct cgraph_node *node = cgraph_get_create_node (t);
 285       cgraph_mark_address_taken_node (node);
 286       ipa_record_reference ((struct cgraph_node *)data, NULL,
 287                             node, NULL,
 288                             IPA_REF_ADDR, stmt);
 289     }
 290   else if (t && TREE_CODE (t) == VAR_DECL
 291            && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 292     {
 293       struct varpool_node *vnode = varpool_node (t);
 294       int walk_subtrees;
 295
 296       if (lang_hooks.callgraph.analyze_expr)
 297         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 298       varpool_mark_needed_node (vnode);
 299       if (vnode->alias && vnode->extra_name)
 300         vnode = vnode->extra_name;
 301       ipa_record_reference ((struct cgraph_node *)data, NULL,
 302                             NULL, vnode,
 303                             IPA_REF_LOAD, stmt);
 304     }
 305   return false;
 306 }
 307
 308 /* Mark store of T.  */
 309
 310 static bool
 311 mark_store (gimple stmt, tree t, void *data)
 312 {
 313   t = get_base_address (t);
 314   if (t && TREE_CODE (t) == VAR_DECL
 315       && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 316     {
 317       struct varpool_node *vnode = varpool_node (t);
 318       int walk_subtrees;
 319
 320       if (lang_hooks.callgraph.analyze_expr)
 321         lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
 322       varpool_mark_needed_node (vnode);
 323       if (vnode->alias && vnode->extra_name)
 324         vnode = vnode->extra_name;
 325       ipa_record_reference ((struct cgraph_node *)data, NULL,
 326                             NULL, vnode,
 327                             IPA_REF_STORE, stmt);
 328      }
 329   return false;
 330 }
 331
 332 /* Create cgraph edges for function calls.
 333    Also look for functions and variables having addresses taken.  */
 334
 335 static unsigned int
 336 build_cgraph_edges (void)
 337 {
 338   basic_block bb;
 339   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 340   struct pointer_set_t *visited_nodes = pointer_set_create ();
 341   gimple_stmt_iterator gsi;
 342   tree decl;
 343   unsigned ix;
 344
 345   /* Create the callgraph edges and record the nodes referenced by the function.
 346      body.  */
 347   FOR_EACH_BB (bb)
 348     {
 349       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 350         {
 351           gimple stmt = gsi_stmt (gsi);
 352           tree decl;
 353
 354           if (is_gimple_call (stmt))
 355             {
 356               int freq = compute_call_stmt_bb_frequency (current_function_decl,
 357                                                          bb);
 358               decl = gimple_call_fndecl (stmt);
 359               if (decl)
 360                 cgraph_create_edge (node, cgraph_get_create_node (decl),
 361                                     stmt, bb->count, freq);
 362               else
 363                 cgraph_create_indirect_edge (node, stmt,
 364                                              gimple_call_flags (stmt),
 365                                              bb->count, freq);
 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_get_create_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_get_create_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_get_create_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_get_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_get_create_node (decl), stmt,
 470                                     bb->count, freq);
 471               else
 472                 cgraph_create_indirect_edge (node, stmt,
 473                                              gimple_call_flags (stmt),
 474                                              bb->count, freq);
 475             }
 476           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 477                                          mark_store, mark_address);
 478
 479         }
 480       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 481         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 482                                        mark_load, mark_store, mark_address);
 483     }
 484   record_eh_tables (node, cfun);
 485   gcc_assert (!node->global.inlined_to);
 486
 487   return 0;
 488 }
 489
 490 /* Rebuild cgraph edges for current function node.  This needs to be run after
 491    passes that don't update the cgraph.  */
 492
 493 void
 494 cgraph_rebuild_references (void)
 495 {
 496   basic_block bb;
 497   struct cgraph_node *node = cgraph_get_node (current_function_decl);
 498   gimple_stmt_iterator gsi;
 499
 500   ipa_remove_all_references (&node->ref_list);
 501
 502   node->count = ENTRY_BLOCK_PTR->count;
 503
 504   FOR_EACH_BB (bb)
 505     {
 506       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 507         {
 508           gimple stmt = gsi_stmt (gsi);
 509
 510           walk_stmt_load_store_addr_ops (stmt, node, mark_load,
 511                                          mark_store, mark_address);
 512
 513         }
 514       for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
 515         walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
 516                                        mark_load, mark_store, mark_address);
 517     }
 518   record_eh_tables (node, cfun);
 519 }
 520
 521 struct gimple_opt_pass pass_rebuild_cgraph_edges =
 522 {
 523  {
 524   GIMPLE_PASS,
 525   "*rebuild_cgraph_edges",              /* name */
 526   NULL,                                 /* gate */
 527   rebuild_cgraph_edges,                 /* execute */
 528   NULL,                                 /* sub */
 529   NULL,                                 /* next */
 530   0,                                    /* static_pass_number */
 531   TV_CGRAPH,                            /* tv_id */
 532   PROP_cfg,                             /* properties_required */
 533   0,                                    /* properties_provided */
 534   0,                                    /* properties_destroyed */
 535   0,                                    /* todo_flags_start */
 536   0,                                    /* todo_flags_finish */
 537  }
 538 };
 539
 540
 541 static unsigned int
 542 remove_cgraph_callee_edges (void)
 543 {
 544   cgraph_node_remove_callees (cgraph_get_node (current_function_decl));
 545   return 0;
 546 }
 547
 548 struct gimple_opt_pass pass_remove_cgraph_callee_edges =
 549 {
 550  {
 551   GIMPLE_PASS,
 552   "*remove_cgraph_callee_edges",                /* name */
 553   NULL,                                 /* gate */
 554   remove_cgraph_callee_edges,           /* execute */
 555   NULL,                                 /* sub */
 556   NULL,                                 /* next */
 557   0,                                    /* static_pass_number */
 558   TV_NONE,                              /* tv_id */
 559   0,                                    /* properties_required */
 560   0,                                    /* properties_provided */
 561   0,                                    /* properties_destroyed */
 562   0,                                    /* todo_flags_start */
 563   0,                                    /* todo_flags_finish */
 564  }
 565 };