gcc/cgraphbuild.c

   1 /* Callgraph construction.
   2    Copyright (C) 2003-2021 Free Software Foundation, Inc.
   3    Contributed by Jan Hubicka
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "backend.h"
  25 #include "tree.h"
  26 #include "gimple.h"
  27 #include "tree-pass.h"
  28 #include "cgraph.h"
  29 #include "gimple-fold.h"
  30 #include "gimple-iterator.h"
  31 #include "gimple-walk.h"
  32 #include "ipa-utils.h"
  33 #include "except.h"
  34
  35 /* Context of record_reference.  */
  36 struct record_reference_ctx
  37 {
  38   bool only_vars;
  39   struct varpool_node *varpool_node;
  40 };
  41
  42 /* Walk tree and record all calls and references to functions/variables.
  43    Called via walk_tree: TP is pointer to tree to be examined.
  44    When DATA is non-null, record references to callgraph.
  45    */
  46
  47 static tree
  48 record_reference (tree *tp, int *walk_subtrees, void *data)
  49 {
  50   tree t = *tp;
  51   tree decl;
  52   record_reference_ctx *ctx = (record_reference_ctx *)data;
  53
  54   t = canonicalize_constructor_val (t, NULL);
  55   if (!t)
  56     t = *tp;
  57   else if (t != *tp)
  58     *tp = t;
  59
  60   switch (TREE_CODE (t))
  61     {
  62     case VAR_DECL:
  63     case FUNCTION_DECL:
  64       gcc_unreachable ();
  65       break;
  66
  67     case FDESC_EXPR:
  68     case ADDR_EXPR:
  69       /* Record dereferences to the functions.  This makes the
  70          functions reachable unconditionally.  */
  71       decl = get_base_var (*tp);
  72       if (TREE_CODE (decl) == FUNCTION_DECL)
  73         {
  74           cgraph_node *node = cgraph_node::get_create (decl);
  75           if (!ctx->only_vars)
  76             node->mark_address_taken ();
  77           ctx->varpool_node->create_reference (node, IPA_REF_ADDR);
  78         }
  79
  80       if (VAR_P (decl))
  81         {
  82           varpool_node *vnode = varpool_node::get_create (decl);
  83           ctx->varpool_node->create_reference (vnode, IPA_REF_ADDR);
  84         }
  85       *walk_subtrees = 0;
  86       break;
  87
  88     default:
  89       /* Save some cycles by not walking types and declaration as we
  90          won't find anything useful there anyway.  */
  91       if (IS_TYPE_OR_DECL_P (*tp))
  92         {
  93           *walk_subtrees = 0;
  94           break;
  95         }
  96       break;
  97     }
  98
  99   return NULL_TREE;
 100 }
 101
 102 /* Record references to typeinfos in the type list LIST.  */
 103
 104 static void
 105 record_type_list (cgraph_node *node, tree list)
 106 {
 107   for (; list; list = TREE_CHAIN (list))
 108     {
 109       tree type = TREE_VALUE (list);
 110
 111       if (TYPE_P (type))
 112         type = lookup_type_for_runtime (type);
 113       STRIP_NOPS (type);
 114       if (TREE_CODE (type) == ADDR_EXPR)
 115         {
 116           type = TREE_OPERAND (type, 0);
 117           if (VAR_P (type))
 118             {
 119               varpool_node *vnode = varpool_node::get_create (type);
 120               node->create_reference (vnode, IPA_REF_ADDR);
 121             }
 122         }
 123     }
 124 }
 125
 126 /* Record all references we will introduce by producing EH tables
 127    for NODE.  */
 128
 129 static void
 130 record_eh_tables (cgraph_node *node, function *fun)
 131 {
 132   eh_region i;
 133
 134   if (DECL_FUNCTION_PERSONALITY (node->decl))
 135     {
 136       tree per_decl = DECL_FUNCTION_PERSONALITY (node->decl);
 137       cgraph_node *per_node = cgraph_node::get_create (per_decl);
 138
 139       node->create_reference (per_node, IPA_REF_ADDR);
 140       per_node->mark_address_taken ();
 141     }
 142
 143   i = fun->eh->region_tree;
 144   if (!i)
 145     return;
 146
 147   while (1)
 148     {
 149       switch (i->type)
 150         {
 151         case ERT_CLEANUP:
 152         case ERT_MUST_NOT_THROW:
 153           break;
 154
 155         case ERT_TRY:
 156           {
 157             eh_catch c;
 158             for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
 159               record_type_list (node, c->type_list);
 160           }
 161           break;
 162
 163         case ERT_ALLOWED_EXCEPTIONS:
 164           record_type_list (node, i->u.allowed.type_list);
 165           break;
 166         }
 167       /* If there are sub-regions, process them.  */
 168       if (i->inner)
 169         i = i->inner;
 170       /* If there are peers, process them.  */
 171       else if (i->next_peer)
 172         i = i->next_peer;
 173       /* Otherwise, step back up the tree to the next peer.  */
 174       else
 175         {
 176           do
 177             {
 178               i = i->outer;
 179               if (i == NULL)
 180                 return;
 181             }
 182           while (i->next_peer == NULL);
 183           i = i->next_peer;
 184         }
 185     }
 186 }
 187
 188 /* Computes the frequency of the call statement so that it can be stored in
 189    cgraph_edge.  BB is the basic block of the call statement.  */
 190 int
 191 compute_call_stmt_bb_frequency (tree decl, basic_block bb)
 192 {
 193   return bb->count.to_cgraph_frequency
 194       (ENTRY_BLOCK_PTR_FOR_FN (DECL_STRUCT_FUNCTION (decl))->count);
 195 }
 196
 197 /* Mark address taken in STMT.  */
 198
 199 static bool
 200 mark_address (gimple *stmt, tree addr, tree, void *data)
 201 {
 202   addr = get_base_address (addr);
 203   if (TREE_CODE (addr) == FUNCTION_DECL)
 204     {
 205       cgraph_node *node = cgraph_node::get_create (addr);
 206       node->mark_address_taken ();
 207       ((symtab_node *)data)->create_reference (node, IPA_REF_ADDR, stmt);
 208     }
 209   else if (addr && VAR_P (addr)
 210            && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
 211     {
 212       varpool_node *vnode = varpool_node::get_create (addr);
 213
 214       ((symtab_node *)data)->create_reference (vnode, IPA_REF_ADDR, stmt);
 215     }
 216
 217   return false;
 218 }
 219
 220 /* Mark load of T.  */
 221
 222 static bool
 223 mark_load (gimple *stmt, tree t, tree, void *data)
 224 {
 225   t = get_base_address (t);
 226   if (t && TREE_CODE (t) == FUNCTION_DECL)
 227     {
 228       /* ??? This can happen on platforms with descriptors when these are
 229          directly manipulated in the code.  Pretend that it's an address.  */
 230       cgraph_node *node = cgraph_node::get_create (t);
 231       node->mark_address_taken ();
 232       ((symtab_node *)data)->create_reference (node, IPA_REF_ADDR, stmt);
 233     }
 234   else if (t && VAR_P (t) && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 235     {
 236       varpool_node *vnode = varpool_node::get_create (t);
 237
 238       ((symtab_node *)data)->create_reference (vnode, IPA_REF_LOAD, stmt);
 239     }
 240   return false;
 241 }
 242
 243 /* Mark store of T.  */
 244
 245 static bool
 246 mark_store (gimple *stmt, tree t, tree, void *data)
 247 {
 248   t = get_base_address (t);
 249   if (t && VAR_P (t) && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
 250     {
 251       varpool_node *vnode = varpool_node::get_create (t);
 252
 253       ((symtab_node *)data)->create_reference (vnode, IPA_REF_STORE, stmt);
 254      }
 255   return false;
 256 }
 257
 258 /* Record all references from cgraph_node that are taken in statement STMT.  */
 259
 260 void
 261 cgraph_node::record_stmt_references (gimple *stmt)
 262 {
 263   walk_stmt_load_store_addr_ops (stmt, this, mark_load, mark_store,
 264                                  mark_address);
 265 }
 266
 267 /* Create cgraph edges for function calls.
 268    Also look for functions and variables having addresses taken.  */
 269
 270 namespace {
 271
 272 const pass_data pass_data_build_cgraph_edges =
 273 {
 274   GIMPLE_PASS, /* type */
 275   "*build_cgraph_edges", /* name */
 276   OPTGROUP_NONE, /* optinfo_flags */
 277   TV_NONE, /* tv_id */
 278   PROP_cfg, /* properties_required */
 279   0, /* properties_provided */
 280   0, /* properties_destroyed */
 281   0, /* todo_flags_start */
 282   0, /* todo_flags_finish */
 283 };
 284
 285 class pass_build_cgraph_edges : public gimple_opt_pass
 286 {
 287 public:
 288   pass_build_cgraph_edges (gcc::context *ctxt)
 289     : gimple_opt_pass (pass_data_build_cgraph_edges, ctxt)
 290   {}
 291
 292   /* opt_pass methods: */
 293   virtual unsigned int execute (function *);
 294
 295 }; // class pass_build_cgraph_edges
 296
 297 unsigned int
 298 pass_build_cgraph_edges::execute (function *fun)
 299 {
 300   basic_block bb;
 301   cgraph_node *node = cgraph_node::get (current_function_decl);
 302   gimple_stmt_iterator gsi;
 303   tree decl;
 304   unsigned ix;
 305
 306   /* Create the callgraph edges and record the nodes referenced by the function.
 307      body.  */
 308   FOR_EACH_BB_FN (bb, fun)
 309     {
 310       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 311         {
 312           gimple *stmt = gsi_stmt (gsi);
 313           tree decl;
 314
 315           if (is_gimple_debug (stmt))
 316             continue;
 317
 318           if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 319             {
 320               decl = gimple_call_fndecl (call_stmt);
 321               if (decl)
 322                 node->create_edge (cgraph_node::get_create (decl), call_stmt, bb->count);
 323               else if (gimple_call_internal_p (call_stmt))
 324                 ;
 325               else
 326                 node->create_indirect_edge (call_stmt,
 327                                             gimple_call_flags (call_stmt),
 328                                             bb->count);
 329             }
 330           node->record_stmt_references (stmt);
 331           if (gomp_parallel *omp_par_stmt = dyn_cast <gomp_parallel *> (stmt))
 332             {
 333               tree fn = gimple_omp_parallel_child_fn (omp_par_stmt);
 334               node->create_reference (cgraph_node::get_create (fn),
 335                                       IPA_REF_ADDR, stmt);
 336             }
 337           if (gimple_code (stmt) == GIMPLE_OMP_TASK)
 338             {
 339               tree fn = gimple_omp_task_child_fn (stmt);
 340               if (fn)
 341                 node->create_reference (cgraph_node::get_create (fn),
 342                                         IPA_REF_ADDR, stmt);
 343               fn = gimple_omp_task_copy_fn (stmt);
 344               if (fn)
 345                 node->create_reference (cgraph_node::get_create (fn),
 346                                         IPA_REF_ADDR, stmt);
 347             }
 348         }
 349       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 350         node->record_stmt_references (gsi_stmt (gsi));
 351    }
 352
 353   /* Look for initializers of constant variables and private statics.  */
 354   FOR_EACH_LOCAL_DECL (fun, ix, decl)
 355     if (VAR_P (decl)
 356         && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
 357         && !DECL_HAS_VALUE_EXPR_P (decl)
 358         && TREE_TYPE (decl) != error_mark_node)
 359       varpool_node::finalize_decl (decl);
 360   record_eh_tables (node, fun);
 361
 362   return 0;
 363 }
 364
 365 } // anon namespace
 366
 367 gimple_opt_pass *
 368 make_pass_build_cgraph_edges (gcc::context *ctxt)
 369 {
 370   return new pass_build_cgraph_edges (ctxt);
 371 }
 372
 373 /* Record references to functions and other variables present in the
 374    initial value of DECL, a variable.
 375    When ONLY_VARS is true, we mark needed only variables, not functions.  */
 376
 377 void
 378 record_references_in_initializer (tree decl, bool only_vars)
 379 {
 380   varpool_node *node = varpool_node::get_create (decl);
 381   hash_set<tree> visited_nodes;
 382   record_reference_ctx ctx = {false, NULL};
 383
 384   ctx.varpool_node = node;
 385   ctx.only_vars = only_vars;
 386   walk_tree (&DECL_INITIAL (decl), record_reference,
 387              &ctx, &visited_nodes);
 388 }
 389
 390 /* Rebuild cgraph edges for current function node.  This needs to be run after
 391    passes that don't update the cgraph.  */
 392
 393 unsigned int
 394 cgraph_edge::rebuild_edges (void)
 395 {
 396   basic_block bb;
 397   cgraph_node *node = cgraph_node::get (current_function_decl);
 398   gimple_stmt_iterator gsi;
 399
 400   node->remove_callees ();
 401   node->remove_all_references ();
 402
 403   node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;
 404
 405   FOR_EACH_BB_FN (bb, cfun)
 406     {
 407       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 408         {
 409           gimple *stmt = gsi_stmt (gsi);
 410           tree decl;
 411
 412           if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 413             {
 414               decl = gimple_call_fndecl (call_stmt);
 415               if (decl)
 416                 node->create_edge (cgraph_node::get_create (decl), call_stmt,
 417                                    bb->count);
 418               else if (gimple_call_internal_p (call_stmt))
 419                 ;
 420               else
 421                 node->create_indirect_edge (call_stmt,
 422                                             gimple_call_flags (call_stmt),
 423                                             bb->count);
 424             }
 425           node->record_stmt_references (stmt);
 426         }
 427       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 428         node->record_stmt_references (gsi_stmt (gsi));
 429     }
 430   record_eh_tables (node, cfun);
 431   gcc_assert (!node->inlined_to);
 432   return 0;
 433 }
 434
 435 /* Rebuild cgraph references for current function node.  This needs to be run
 436    after passes that don't update the cgraph.  */
 437
 438 void
 439 cgraph_edge::rebuild_references (void)
 440 {
 441   basic_block bb;
 442   cgraph_node *node = cgraph_node::get (current_function_decl);
 443   gimple_stmt_iterator gsi;
 444   ipa_ref *ref = NULL;
 445   int i;
 446
 447   /* Keep speculative references for further cgraph edge expansion.  */
 448   for (i = 0; node->iterate_reference (i, ref);)
 449     if (!ref->speculative)
 450       ref->remove_reference ();
 451     else
 452       i++;
 453
 454   FOR_EACH_BB_FN (bb, cfun)
 455     {
 456       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 457         node->record_stmt_references (gsi_stmt (gsi));
 458       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 459         node->record_stmt_references (gsi_stmt (gsi));
 460     }
 461   record_eh_tables (node, cfun);
 462 }
 463
 464 namespace {
 465
 466 const pass_data pass_data_rebuild_cgraph_edges =
 467 {
 468   GIMPLE_PASS, /* type */
 469   "*rebuild_cgraph_edges", /* name */
 470   OPTGROUP_NONE, /* optinfo_flags */
 471   TV_CGRAPH, /* tv_id */
 472   PROP_cfg, /* properties_required */
 473   0, /* properties_provided */
 474   0, /* properties_destroyed */
 475   0, /* todo_flags_start */
 476   0, /* todo_flags_finish */
 477 };
 478
 479 class pass_rebuild_cgraph_edges : public gimple_opt_pass
 480 {
 481 public:
 482   pass_rebuild_cgraph_edges (gcc::context *ctxt)
 483     : gimple_opt_pass (pass_data_rebuild_cgraph_edges, ctxt)
 484   {}
 485
 486   /* opt_pass methods: */
 487   opt_pass * clone () { return new pass_rebuild_cgraph_edges (m_ctxt); }
 488   virtual unsigned int execute (function *)
 489   {
 490     return cgraph_edge::rebuild_edges ();
 491   }
 492
 493 }; // class pass_rebuild_cgraph_edges
 494
 495 } // anon namespace
 496
 497 gimple_opt_pass *
 498 make_pass_rebuild_cgraph_edges (gcc::context *ctxt)
 499 {
 500   return new pass_rebuild_cgraph_edges (ctxt);
 501 }
 502
 503
 504 namespace {
 505
 506 const pass_data pass_data_remove_cgraph_callee_edges =
 507 {
 508   GIMPLE_PASS, /* type */
 509   "*remove_cgraph_callee_edges", /* name */
 510   OPTGROUP_NONE, /* optinfo_flags */
 511   TV_NONE, /* tv_id */
 512   0, /* properties_required */
 513   0, /* properties_provided */
 514   0, /* properties_destroyed */
 515   0, /* todo_flags_start */
 516   0, /* todo_flags_finish */
 517 };
 518
 519 class pass_remove_cgraph_callee_edges : public gimple_opt_pass
 520 {
 521 public:
 522   pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 523     : gimple_opt_pass (pass_data_remove_cgraph_callee_edges, ctxt)
 524   {}
 525
 526   /* opt_pass methods: */
 527   opt_pass * clone () {
 528     return new pass_remove_cgraph_callee_edges (m_ctxt);
 529   }
 530   virtual unsigned int execute (function *);
 531
 532 }; // class pass_remove_cgraph_callee_edges
 533
 534 unsigned int
 535 pass_remove_cgraph_callee_edges::execute (function *)
 536 {
 537   cgraph_node *node = cgraph_node::get (current_function_decl);
 538   node->remove_callees ();
 539   node->remove_all_references ();
 540   return 0;
 541 }
 542
 543 } // anon namespace
 544
 545 gimple_opt_pass *
 546 make_pass_remove_cgraph_callee_edges (gcc::context *ctxt)
 547 {
 548   return new pass_remove_cgraph_callee_edges (ctxt);
 549 }