gcc/tree-optimize.c

   1 /* Top-level control of tree optimizations.
   2    Copyright 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
   3    Contributed by Diego Novillo <dnovillo@redhat.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "tree.h"
  27 #include "rtl.h"
  28 #include "tm_p.h"
  29 #include "hard-reg-set.h"
  30 #include "basic-block.h"
  31 #include "output.h"
  32 #include "expr.h"
  33 #include "diagnostic.h"
  34 #include "basic-block.h"
  35 #include "flags.h"
  36 #include "tree-flow.h"
  37 #include "tree-dump.h"
  38 #include "timevar.h"
  39 #include "function.h"
  40 #include "langhooks.h"
  41 #include "toplev.h"
  42 #include "flags.h"
  43 #include "cgraph.h"
  44 #include "tree-inline.h"
  45 #include "tree-mudflap.h"
  46 #include "tree-pass.h"
  47 #include "ggc.h"
  48 #include "cgraph.h"
  49 #include "graph.h"
  50 #include "cfgloop.h"
  51 #include "except.h"
  52
  53
  54 /* Global variables used to communicate with passes.  */
  55 int dump_flags;
  56 bool in_gimple_form;
  57
  58 /* The root of the compilation pass tree, once constructed.  */
  59 static struct tree_opt_pass *all_passes, *all_ipa_passes, * all_lowering_passes;
  60
  61 /* Gate: execute, or not, all of the non-trivial optimizations.  */
  62
  63 static bool
  64 gate_all_optimizations (void)
  65 {
  66   return (optimize >= 1
  67           /* Don't bother doing anything if the program has errors.  */
  68           && !(errorcount || sorrycount));
  69 }
  70
  71 static struct tree_opt_pass pass_all_optimizations =
  72 {
  73   NULL,                                 /* name */
  74   gate_all_optimizations,               /* gate */
  75   NULL,                                 /* execute */
  76   NULL,                                 /* sub */
  77   NULL,                                 /* next */
  78   0,                                    /* static_pass_number */
  79   0,                                    /* tv_id */
  80   0,                                    /* properties_required */
  81   0,                                    /* properties_provided */
  82   0,                                    /* properties_destroyed */
  83   0,                                    /* todo_flags_start */
  84   0,                                    /* todo_flags_finish */
  85   0                                     /* letter */
  86 };
  87
  88 /* Pass: cleanup the CFG just before expanding trees to RTL.
  89    This is just a round of label cleanups and case node grouping
  90    because after the tree optimizers have run such cleanups may
  91    be necessary.  */
  92
  93 static void
  94 execute_cleanup_cfg_post_optimizing (void)
  95 {
  96   cleanup_tree_cfg ();
  97   cleanup_dead_labels ();
  98   group_case_labels ();
  99 }
 100
 101 static struct tree_opt_pass pass_cleanup_cfg_post_optimizing =
 102 {
 103   "final_cleanup",                      /* name */
 104   NULL,                                 /* gate */
 105   execute_cleanup_cfg_post_optimizing,  /* execute */
 106   NULL,                                 /* sub */
 107   NULL,                                 /* next */
 108   0,                                    /* static_pass_number */
 109   0,                                    /* tv_id */
 110   PROP_cfg,                             /* properties_required */
 111   0,                                    /* properties_provided */
 112   0,                                    /* properties_destroyed */
 113   0,                                    /* todo_flags_start */
 114   TODO_dump_func,                                       /* todo_flags_finish */
 115   0                                     /* letter */
 116 };
 117
 118 /* Pass: do the actions required to finish with tree-ssa optimization
 119    passes.  */
 120
 121 static void
 122 execute_free_datastructures (void)
 123 {
 124   tree *chain;
 125
 126   /* ??? This isn't the right place for this.  Worse, it got computed
 127      more or less at random in various passes.  */
 128   free_dominance_info (CDI_DOMINATORS);
 129
 130   /* Emit gotos for implicit jumps.  */
 131   disband_implicit_edges ();
 132
 133   /* Remove the ssa structures.  Do it here since this includes statement
 134      annotations that need to be intact during disband_implicit_edges.  */
 135   delete_tree_ssa ();
 136
 137   /* Re-chain the statements from the blocks.  */
 138   chain = &DECL_SAVED_TREE (current_function_decl);
 139   *chain = alloc_stmt_list ();
 140
 141   /* And get rid of annotations we no longer need.  */
 142   delete_tree_cfg_annotations ();
 143 }
 144
 145 static struct tree_opt_pass pass_free_datastructures =
 146 {
 147   NULL,                                 /* name */
 148   NULL,                                 /* gate */
 149   execute_free_datastructures,                  /* execute */
 150   NULL,                                 /* sub */
 151   NULL,                                 /* next */
 152   0,                                    /* static_pass_number */
 153   0,                                    /* tv_id */
 154   PROP_cfg,                             /* properties_required */
 155   0,                                    /* properties_provided */
 156   0,                                    /* properties_destroyed */
 157   0,                                    /* todo_flags_start */
 158   0,                                    /* todo_flags_finish */
 159   0                                     /* letter */
 160 };
 161
 162 /* Pass: fixup_cfg - IPA passes or compilation of earlier functions might've
 163    changed some properties - such as marked functions nothrow.  Remove now
 164    redundant edges and basic blocks.  */
 165
 166 static void
 167 execute_fixup_cfg (void)
 168 {
 169   basic_block bb;
 170   block_stmt_iterator bsi;
 171
 172   if (cfun->eh)
 173     FOR_EACH_BB (bb)
 174       {
 175         for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
 176           {
 177             tree stmt = bsi_stmt (bsi);
 178             tree call = get_call_expr_in (stmt);
 179
 180             if (call && call_expr_flags (call) & (ECF_CONST | ECF_PURE))
 181               TREE_SIDE_EFFECTS (call) = 0;
 182             if (!tree_could_throw_p (stmt) && lookup_stmt_eh_region (stmt))
 183               remove_stmt_from_eh_region (stmt);
 184           }
 185         tree_purge_dead_eh_edges (bb);
 186       }
 187
 188   cleanup_tree_cfg ();
 189 }
 190
 191 static struct tree_opt_pass pass_fixup_cfg =
 192 {
 193   NULL,                                 /* name */
 194   NULL,                                 /* gate */
 195   execute_fixup_cfg,                    /* execute */
 196   NULL,                                 /* sub */
 197   NULL,                                 /* next */
 198   0,                                    /* static_pass_number */
 199   0,                                    /* tv_id */
 200   PROP_cfg,                             /* properties_required */
 201   0,                                    /* properties_provided */
 202   0,                                    /* properties_destroyed */
 203   0,                                    /* todo_flags_start */
 204   0,                                    /* todo_flags_finish */
 205   0                                     /* letter */
 206 };
 207
 208 /* Do the actions required to initialize internal data structures used
 209    in tree-ssa optimization passes.  */
 210
 211 static void
 212 execute_init_datastructures (void)
 213 {
 214   /* Allocate hash tables, arrays and other structures.  */
 215   init_tree_ssa ();
 216 }
 217
 218 static struct tree_opt_pass pass_init_datastructures =
 219 {
 220   NULL,                                 /* name */
 221   NULL,                                 /* gate */
 222   execute_init_datastructures,          /* execute */
 223   NULL,                                 /* sub */
 224   NULL,                                 /* next */
 225   0,                                    /* static_pass_number */
 226   0,                                    /* tv_id */
 227   PROP_cfg,                             /* properties_required */
 228   0,                                    /* properties_provided */
 229   0,                                    /* properties_destroyed */
 230   0,                                    /* todo_flags_start */
 231   0,                                    /* todo_flags_finish */
 232   0                                     /* letter */
 233 };
 234
 235 /* Iterate over the pass tree allocating dump file numbers.  We want
 236    to do this depth first, and independent of whether the pass is
 237    enabled or not.  */
 238
 239 static void
 240 register_one_dump_file (struct tree_opt_pass *pass, bool ipa, int n)
 241 {
 242   char *dot_name, *flag_name, *glob_name;
 243   char num[10];
 244
 245   /* See below in next_pass_1.  */
 246   num[0] = '\0';
 247   if (pass->static_pass_number != -1)
 248     sprintf (num, "%d", ((int) pass->static_pass_number < 0
 249                          ? 1 : pass->static_pass_number));
 250
 251   dot_name = concat (".", pass->name, num, NULL);
 252   if (ipa)
 253     {
 254       flag_name = concat ("ipa-", pass->name, num, NULL);
 255       glob_name = concat ("ipa-", pass->name, NULL);
 256       /* First IPA dump is cgraph that is dumped via separate channels.  */
 257       pass->static_pass_number = dump_register (dot_name, flag_name, glob_name,
 258                                                 TDF_IPA, n + 1, 0);
 259     }
 260   else if (pass->properties_provided & PROP_trees)
 261     {
 262       flag_name = concat ("tree-", pass->name, num, NULL);
 263       glob_name = concat ("tree-", pass->name, NULL);
 264       pass->static_pass_number = dump_register (dot_name, flag_name, glob_name,
 265                                                 TDF_TREE, n + TDI_tree_all, 0);
 266     }
 267   else
 268     {
 269       flag_name = concat ("rtl-", pass->name, num, NULL);
 270       glob_name = concat ("rtl-", pass->name, NULL);
 271       pass->static_pass_number = dump_register (dot_name, flag_name, glob_name,
 272                                                 TDF_RTL, n, pass->letter);
 273     }
 274 }
 275
 276 static int
 277 register_dump_files (struct tree_opt_pass *pass, bool ipa, int properties)
 278 {
 279   static int n = 0;
 280   do
 281     {
 282       int new_properties;
 283       int pass_number;
 284
 285       pass->properties_required = properties;
 286       new_properties =
 287         (properties | pass->properties_provided) & ~pass->properties_destroyed;
 288
 289       /* Reset the counter when we reach RTL-based passes.  */
 290       if ((pass->properties_provided ^ pass->properties_required) & PROP_rtl)
 291         n = 0;
 292
 293       pass_number = n;
 294       if (pass->name)
 295         n++;
 296
 297       if (pass->sub)
 298         new_properties = register_dump_files (pass->sub, ipa, new_properties);
 299
 300       /* If we have a gate, combine the properties that we could have with
 301          and without the pass being examined.  */
 302       if (pass->gate)
 303         properties &= new_properties;
 304       else
 305         properties = new_properties;
 306
 307       pass->properties_provided = properties;
 308       if (pass->name)
 309         register_one_dump_file (pass, ipa, pass_number);
 310
 311       pass = pass->next;
 312     }
 313   while (pass);
 314
 315   return properties;
 316 }
 317
 318 /* Add a pass to the pass list. Duplicate the pass if it's already
 319    in the list.  */
 320
 321 static struct tree_opt_pass **
 322 next_pass_1 (struct tree_opt_pass **list, struct tree_opt_pass *pass)
 323 {
 324
 325   /* A nonzero static_pass_number indicates that the
 326      pass is already in the list.  */
 327   if (pass->static_pass_number)
 328     {
 329       struct tree_opt_pass *new;
 330
 331       new = xmalloc (sizeof (*new));
 332       memcpy (new, pass, sizeof (*new));
 333
 334       /* Indicate to register_dump_files that this pass has duplicates,
 335          and so it should rename the dump file.  The first instance will
 336          be -1, and be number of duplicates = -static_pass_number - 1.
 337          Subsequent instances will be > 0 and just the duplicate number.  */
 338       if (pass->name)
 339         {
 340           pass->static_pass_number -= 1;
 341           new->static_pass_number = -pass->static_pass_number;
 342         }
 343
 344       *list = new;
 345     }
 346   else
 347     {
 348       pass->static_pass_number = -1;
 349       *list = pass;
 350     }
 351
 352   return &(*list)->next;
 353
 354 }
 355
 356 /* Construct the pass tree.  */
 357
 358 void
 359 init_tree_optimization_passes (void)
 360 {
 361   struct tree_opt_pass **p;
 362
 363 #define NEXT_PASS(PASS)  (p = next_pass_1 (p, &PASS))
 364   /* Intraprocedural optimization passes.  */
 365   p = &all_ipa_passes;
 366   NEXT_PASS (pass_ipa_inline);
 367   *p = NULL;
 368
 369   /* All passes needed to lower the function into shape optimizers can operate
 370      on.  These passes are performed before interprocedural passes, unlike rest
 371      of local passes (all_passes).  */
 372   p = &all_lowering_passes;
 373   NEXT_PASS (pass_remove_useless_stmts);
 374   NEXT_PASS (pass_mudflap_1);
 375   NEXT_PASS (pass_lower_cf);
 376   NEXT_PASS (pass_lower_eh);
 377   NEXT_PASS (pass_build_cfg);
 378   NEXT_PASS (pass_pre_expand);
 379   NEXT_PASS (pass_warn_function_return);
 380   *p = NULL;
 381
 382   p = &all_passes;
 383   NEXT_PASS (pass_fixup_cfg);
 384   NEXT_PASS (pass_tree_profile);
 385   NEXT_PASS (pass_init_datastructures);
 386   NEXT_PASS (pass_all_optimizations);
 387   NEXT_PASS (pass_warn_function_noreturn);
 388   NEXT_PASS (pass_mudflap_2);
 389   NEXT_PASS (pass_free_datastructures);
 390   NEXT_PASS (pass_expand);
 391   NEXT_PASS (pass_rest_of_compilation);
 392   *p = NULL;
 393
 394   p = &pass_all_optimizations.sub;
 395   NEXT_PASS (pass_referenced_vars);
 396   NEXT_PASS (pass_create_structure_vars);
 397   NEXT_PASS (pass_build_ssa);
 398   NEXT_PASS (pass_may_alias);
 399   NEXT_PASS (pass_rename_ssa_copies);
 400   NEXT_PASS (pass_early_warn_uninitialized);
 401
 402   /* Initial scalar cleanups.  */
 403   NEXT_PASS (pass_ccp);
 404   NEXT_PASS (pass_fre);
 405   NEXT_PASS (pass_dce);
 406   NEXT_PASS (pass_forwprop);
 407   NEXT_PASS (pass_vrp);
 408   NEXT_PASS (pass_copy_prop);
 409   NEXT_PASS (pass_dce);
 410   NEXT_PASS (pass_merge_phi);
 411   NEXT_PASS (pass_dominator);
 412
 413   NEXT_PASS (pass_phiopt);
 414   NEXT_PASS (pass_may_alias);
 415   NEXT_PASS (pass_tail_recursion);
 416   NEXT_PASS (pass_profile);
 417   NEXT_PASS (pass_ch);
 418   NEXT_PASS (pass_stdarg);
 419   NEXT_PASS (pass_sra);
 420   /* FIXME: SRA may generate arbitrary gimple code, exposing new
 421      aliased and call-clobbered variables.  As mentioned below,
 422      pass_may_alias should be a TODO item.  */
 423   NEXT_PASS (pass_may_alias);
 424   NEXT_PASS (pass_rename_ssa_copies);
 425   NEXT_PASS (pass_dominator);
 426   NEXT_PASS (pass_copy_prop);
 427   NEXT_PASS (pass_dce);
 428   NEXT_PASS (pass_dse);
 429   NEXT_PASS (pass_may_alias);
 430   NEXT_PASS (pass_forwprop);
 431   NEXT_PASS (pass_phiopt);
 432   NEXT_PASS (pass_store_ccp);
 433   NEXT_PASS (pass_store_copy_prop);
 434   NEXT_PASS (pass_fold_builtins);
 435   /* FIXME: May alias should a TODO but for 4.0.0,
 436      we add may_alias right after fold builtins
 437      which can create arbitrary GIMPLE.  */
 438   NEXT_PASS (pass_may_alias);
 439   NEXT_PASS (pass_cse_reciprocals);
 440   NEXT_PASS (pass_split_crit_edges);
 441   NEXT_PASS (pass_pre);
 442   NEXT_PASS (pass_sink_code);
 443   NEXT_PASS (pass_loop);
 444   NEXT_PASS (pass_dominator);
 445   NEXT_PASS (pass_copy_prop);
 446   NEXT_PASS (pass_cd_dce);
 447   /* FIXME: If DCE is not run before checking for uninitialized uses,
 448      we may get false warnings (e.g., testsuite/gcc.dg/uninit-5.c).
 449      However, this also causes us to misdiagnose cases that should be
 450      real warnings (e.g., testsuite/gcc.dg/pr18501.c).
 451
 452      To fix the false positives in uninit-5.c, we would have to
 453      account for the predicates protecting the set and the use of each
 454      variable.  Using a representation like Gated Single Assignment
 455      may help.  */
 456   NEXT_PASS (pass_late_warn_uninitialized);
 457   NEXT_PASS (pass_dse);
 458   NEXT_PASS (pass_forwprop);
 459   NEXT_PASS (pass_phiopt);
 460   NEXT_PASS (pass_tail_calls);
 461   NEXT_PASS (pass_rename_ssa_copies);
 462   NEXT_PASS (pass_uncprop);
 463   NEXT_PASS (pass_del_ssa);
 464   NEXT_PASS (pass_nrv);
 465   NEXT_PASS (pass_remove_useless_vars);
 466   NEXT_PASS (pass_mark_used_blocks);
 467   NEXT_PASS (pass_cleanup_cfg_post_optimizing);
 468   *p = NULL;
 469
 470   p = &pass_loop.sub;
 471   NEXT_PASS (pass_loop_init);
 472   NEXT_PASS (pass_copy_prop);
 473   NEXT_PASS (pass_lim);
 474   NEXT_PASS (pass_unswitch);
 475   NEXT_PASS (pass_scev_cprop);
 476   NEXT_PASS (pass_record_bounds);
 477   NEXT_PASS (pass_linear_transform);
 478   NEXT_PASS (pass_iv_canon);
 479   NEXT_PASS (pass_if_conversion);
 480   NEXT_PASS (pass_vectorize);
 481   NEXT_PASS (pass_lower_vector_ssa);
 482   NEXT_PASS (pass_complete_unroll);
 483   NEXT_PASS (pass_iv_optimize);
 484   NEXT_PASS (pass_loop_done);
 485   *p = NULL;
 486
 487 #undef NEXT_PASS
 488
 489   register_dump_files (all_lowering_passes, false, PROP_gimple_any);
 490   register_dump_files (all_passes, false, PROP_gimple_any
 491                                           | PROP_gimple_lcf
 492                                           | PROP_gimple_leh
 493                                           | PROP_cfg);
 494   register_dump_files (all_ipa_passes, true, PROP_gimple_any
 495                                              | PROP_gimple_lcf
 496                                              | PROP_gimple_leh
 497                                              | PROP_cfg);
 498 }
 499
 500 static unsigned int last_verified;
 501
 502 static void
 503 execute_todo (struct tree_opt_pass *pass, unsigned int flags, bool use_required)
 504 {
 505   int properties
 506     = use_required ? pass->properties_required : pass->properties_provided;
 507
 508 #if defined ENABLE_CHECKING
 509   if (need_ssa_update_p ())
 510     gcc_assert (flags & TODO_update_ssa_any);
 511 #endif
 512
 513   if (flags & TODO_update_ssa_any)
 514     {
 515       unsigned update_flags = flags & TODO_update_ssa_any;
 516       update_ssa (update_flags);
 517     }
 518
 519   if (flags & TODO_cleanup_cfg)
 520     {
 521       if (current_loops)
 522         cleanup_tree_cfg_loop ();
 523       else
 524         cleanup_tree_cfg ();
 525     }
 526
 527   if ((flags & TODO_dump_func)
 528       && dump_file && current_function_decl)
 529     {
 530       if (properties & PROP_trees)
 531         dump_function_to_file (current_function_decl,
 532                                dump_file, dump_flags);
 533       else if (properties & PROP_cfg)
 534         print_rtl_with_bb (dump_file, get_insns ());
 535       else
 536         print_rtl (dump_file, get_insns ());
 537
 538       /* Flush the file.  If verification fails, we won't be able to
 539          close the file before dieing.  */
 540       fflush (dump_file);
 541     }
 542   if ((flags & TODO_dump_cgraph)
 543       && dump_file && !current_function_decl)
 544     {
 545       dump_cgraph (dump_file);
 546       /* Flush the file.  If verification fails, we won't be able to
 547          close the file before aborting.  */
 548       fflush (dump_file);
 549     }
 550
 551   if (flags & TODO_ggc_collect)
 552     {
 553       ggc_collect ();
 554     }
 555
 556 #if defined ENABLE_CHECKING
 557   if ((pass->properties_required & PROP_ssa)
 558       && !(pass->properties_destroyed & PROP_ssa))
 559     verify_ssa (true);
 560   if (flags & TODO_verify_flow)
 561     verify_flow_info ();
 562   if (flags & TODO_verify_stmts)
 563     verify_stmts ();
 564   if (flags & TODO_verify_loops)
 565     verify_loop_closed_ssa ();
 566 #endif
 567 }
 568
 569 static bool
 570 execute_one_pass (struct tree_opt_pass *pass)
 571 {
 572   unsigned int todo;
 573
 574   /* See if we're supposed to run this pass.  */
 575   if (pass->gate && !pass->gate ())
 576     return false;
 577
 578   /* Note that the folders should only create gimple expressions.
 579      This is a hack until the new folder is ready.  */
 580   in_gimple_form = (pass->properties_provided & PROP_trees) != 0;
 581
 582   /* Run pre-pass verification.  */
 583   todo = pass->todo_flags_start & ~last_verified;
 584   if (todo)
 585     execute_todo (pass, todo, true);
 586
 587   /* If a dump file name is present, open it if enabled.  */
 588   if (pass->static_pass_number != -1)
 589     {
 590       bool initializing_dump = !dump_initialized_p (pass->static_pass_number);
 591       dump_file_name = get_dump_file_name (pass->static_pass_number);
 592       dump_file = dump_begin (pass->static_pass_number, &dump_flags);
 593       if (dump_file && current_function_decl)
 594         {
 595           const char *dname, *aname;
 596           dname = lang_hooks.decl_printable_name (current_function_decl, 2);
 597           aname = (IDENTIFIER_POINTER
 598                    (DECL_ASSEMBLER_NAME (current_function_decl)));
 599           fprintf (dump_file, "\n;; Function %s (%s)%s\n\n", dname, aname,
 600              cfun->function_frequency == FUNCTION_FREQUENCY_HOT
 601              ? " (hot)"
 602              : cfun->function_frequency == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED
 603              ? " (unlikely executed)"
 604              : "");
 605         }
 606
 607       if (initializing_dump
 608           && graph_dump_format != no_graph
 609           && (pass->properties_provided & (PROP_cfg | PROP_rtl))
 610               == (PROP_cfg | PROP_rtl))
 611         clean_graph_dump_file (dump_file_name);
 612     }
 613
 614   /* If a timevar is present, start it.  */
 615   if (pass->tv_id)
 616     timevar_push (pass->tv_id);
 617
 618   /* Do it!  */
 619   if (pass->execute)
 620     pass->execute ();
 621
 622   /* Stop timevar.  */
 623   if (pass->tv_id)
 624     timevar_pop (pass->tv_id);
 625
 626   if (dump_file
 627       && (pass->properties_provided & (PROP_cfg | PROP_rtl))
 628           == (PROP_cfg | PROP_rtl))
 629     print_rtl_with_bb (dump_file, get_insns ());
 630
 631   /* Run post-pass cleanup and verification.  */
 632   todo = pass->todo_flags_finish;
 633   last_verified = todo & TODO_verify_all;
 634   if (todo)
 635     execute_todo (pass, todo, false);
 636
 637   /* Flush and close dump file.  */
 638   if (dump_file_name)
 639     {
 640       free ((char *) dump_file_name);
 641       dump_file_name = NULL;
 642     }
 643   if (dump_file)
 644     {
 645       dump_end (pass->static_pass_number, dump_file);
 646       dump_file = NULL;
 647     }
 648
 649   return true;
 650 }
 651
 652 static void
 653 execute_pass_list (struct tree_opt_pass *pass)
 654 {
 655   do
 656     {
 657       if (execute_one_pass (pass) && pass->sub)
 658         execute_pass_list (pass->sub);
 659       pass = pass->next;
 660     }
 661   while (pass);
 662 }
 663
 664 void
 665 tree_lowering_passes (tree fn)
 666 {
 667   tree saved_current_function_decl = current_function_decl;
 668
 669   current_function_decl = fn;
 670   push_cfun (DECL_STRUCT_FUNCTION (fn));
 671   tree_register_cfg_hooks ();
 672   bitmap_obstack_initialize (NULL);
 673   execute_pass_list (all_lowering_passes);
 674   free_dominance_info (CDI_POST_DOMINATORS);
 675   compact_blocks ();
 676   current_function_decl = saved_current_function_decl;
 677   bitmap_obstack_release (NULL);
 678   pop_cfun ();
 679 }
 680
 681 /* Execute all IPA passes.  */
 682 void
 683 ipa_passes (void)
 684 {
 685    execute_pass_list (all_ipa_passes);
 686 }
 687 \f
 688
 689 /* Update recursively all inlined_to pointers of functions
 690    inlined into NODE to INLINED_TO.  */
 691 static void
 692 update_inlined_to_pointers (struct cgraph_node *node,
 693                             struct cgraph_node *inlined_to)
 694 {
 695   struct cgraph_edge *e;
 696   for (e = node->callees; e; e = e->next_callee)
 697     {
 698       if (e->callee->global.inlined_to)
 699         {
 700           e->callee->global.inlined_to = inlined_to;
 701           update_inlined_to_pointers (e->callee, inlined_to);
 702         }
 703     }
 704 }
 705
 706 \f
 707 /* For functions-as-trees languages, this performs all optimization and
 708    compilation for FNDECL.  */
 709
 710 void
 711 tree_rest_of_compilation (tree fndecl)
 712 {
 713   location_t saved_loc;
 714   struct cgraph_node *saved_node = NULL, *node;
 715
 716   timevar_push (TV_EXPAND);
 717
 718   gcc_assert (!flag_unit_at_a_time || cgraph_global_info_ready);
 719
 720   /* Initialize the RTL code for the function.  */
 721   current_function_decl = fndecl;
 722   saved_loc = input_location;
 723   input_location = DECL_SOURCE_LOCATION (fndecl);
 724   init_function_start (fndecl);
 725
 726   /* Even though we're inside a function body, we still don't want to
 727      call expand_expr to calculate the size of a variable-sized array.
 728      We haven't necessarily assigned RTL to all variables yet, so it's
 729      not safe to try to expand expressions involving them.  */
 730   cfun->x_dont_save_pending_sizes_p = 1;
 731   cfun->after_inlining = true;
 732
 733   node = cgraph_node (fndecl);
 734
 735   /* We might need the body of this function so that we can expand
 736      it inline somewhere else.  This means not lowering some constructs
 737      such as exception handling.  */
 738   if (cgraph_preserve_function_body_p (fndecl))
 739     {
 740       if (!flag_unit_at_a_time)
 741         {
 742           struct cgraph_edge *e;
 743
 744           saved_node = cgraph_clone_node (node, node->count, 1);
 745           for (e = saved_node->callees; e; e = e->next_callee)
 746             if (!e->inline_failed)
 747               cgraph_clone_inlined_nodes (e, true);
 748         }
 749       cfun->saved_static_chain_decl = cfun->static_chain_decl;
 750       save_body (fndecl, &cfun->saved_args, &cfun->saved_static_chain_decl);
 751     }
 752
 753   if (flag_inline_trees)
 754     {
 755       struct cgraph_edge *e;
 756       for (e = node->callees; e; e = e->next_callee)
 757         if (!e->inline_failed || warn_inline)
 758           break;
 759       if (e)
 760         {
 761           timevar_push (TV_INTEGRATION);
 762           optimize_inline_calls (fndecl);
 763           timevar_pop (TV_INTEGRATION);
 764         }
 765     }
 766   /* We are not going to maintain the cgraph edges up to date.
 767      Kill it so it won't confuse us.  */
 768   while (node->callees)
 769     {
 770       /* In non-unit-at-a-time we must mark all referenced functions as needed.
 771          */
 772       if (node->callees->callee->analyzed && !flag_unit_at_a_time)
 773         cgraph_mark_needed_node (node->callees->callee);
 774       cgraph_remove_edge (node->callees);
 775     }
 776
 777   /* We are not going to maintain the cgraph edges up to date.
 778      Kill it so it won't confuse us.  */
 779   cgraph_node_remove_callees (node);
 780
 781
 782   /* Initialize the default bitmap obstack.  */
 783   bitmap_obstack_initialize (NULL);
 784   bitmap_obstack_initialize (&reg_obstack); /* FIXME, only at RTL generation*/
 785
 786   tree_register_cfg_hooks ();
 787   /* Perform all tree transforms and optimizations.  */
 788   execute_pass_list (all_passes);
 789
 790   bitmap_obstack_release (&reg_obstack);
 791
 792   /* Release the default bitmap obstack.  */
 793   bitmap_obstack_release (NULL);
 794
 795   /* Restore original body if still needed.  */
 796   if (cfun->saved_cfg)
 797     {
 798       DECL_ARGUMENTS (fndecl) = cfun->saved_args;
 799       cfun->cfg = cfun->saved_cfg;
 800       cfun->eh = cfun->saved_eh;
 801       cfun->saved_cfg = NULL;
 802       cfun->saved_eh = NULL;
 803       cfun->saved_args = NULL_TREE;
 804       cfun->static_chain_decl = cfun->saved_static_chain_decl;
 805       cfun->saved_static_chain_decl = NULL;
 806       /* When not in unit-at-a-time mode, we must preserve out of line copy
 807          representing node before inlining.  Restore original outgoing edges
 808          using clone we created earlier.  */
 809       if (!flag_unit_at_a_time)
 810         {
 811           struct cgraph_edge *e;
 812
 813           node = cgraph_node (current_function_decl);
 814           cgraph_node_remove_callees (node);
 815           node->callees = saved_node->callees;
 816           saved_node->callees = NULL;
 817           update_inlined_to_pointers (node, node);
 818           for (e = node->callees; e; e = e->next_callee)
 819             e->caller = node;
 820           cgraph_remove_node (saved_node);
 821         }
 822     }
 823   else
 824     DECL_SAVED_TREE (fndecl) = NULL;
 825   cfun = 0;
 826
 827   /* If requested, warn about function definitions where the function will
 828      return a value (usually of some struct or union type) which itself will
 829      take up a lot of stack space.  */
 830   if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))
 831     {
 832       tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));
 833
 834       if (ret_type && TYPE_SIZE_UNIT (ret_type)
 835           && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST
 836           && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),
 837                                    larger_than_size))
 838         {
 839           unsigned int size_as_int
 840             = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));
 841
 842           if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)
 843             warning (0, "%Jsize of return value of %qD is %u bytes",
 844                      fndecl, fndecl, size_as_int);
 845           else
 846             warning (0, "%Jsize of return value of %qD is larger than %wd bytes",
 847                      fndecl, fndecl, larger_than_size);
 848         }
 849     }
 850
 851   if (!flag_inline_trees)
 852     {
 853       DECL_SAVED_TREE (fndecl) = NULL;
 854       if (DECL_STRUCT_FUNCTION (fndecl) == 0
 855           && !cgraph_node (fndecl)->origin)
 856         {
 857           /* Stop pointing to the local nodes about to be freed.
 858              But DECL_INITIAL must remain nonzero so we know this
 859              was an actual function definition.
 860              For a nested function, this is done in c_pop_function_context.
 861              If rest_of_compilation set this to 0, leave it 0.  */
 862           if (DECL_INITIAL (fndecl) != 0)
 863             DECL_INITIAL (fndecl) = error_mark_node;
 864         }
 865     }
 866
 867   input_location = saved_loc;
 868
 869   ggc_collect ();
 870   timevar_pop (TV_EXPAND);
 871 }