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>
5 This file is part of GCC.
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)
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.
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. */
24 #include "coretypes.h"
29 #include "hard-reg-set.h"
30 #include "basic-block.h"
33 #include "diagnostic.h"
34 #include "basic-block.h"
36 #include "tree-flow.h"
37 #include "tree-dump.h"
40 #include "langhooks.h"
44 #include "tree-inline.h"
45 #include "tree-mudflap.h"
46 #include "tree-pass.h"
53 /* Global variables used to communicate with passes. */
55 bitmap vars_to_rename;
58 /* The root of the compilation pass tree, once constructed. */
59 static struct tree_opt_pass *all_passes;
61 /* Pass: dump the gimplified, inlined, functions. */
63 static struct tree_opt_pass pass_gimple =
70 0, /* static_pass_number */
72 0, /* properties_required */
73 PROP_gimple_any, /* properties_provided */
74 0, /* properties_destroyed */
75 0, /* todo_flags_start */
76 TODO_dump_func, /* todo_flags_finish */
80 /* Gate: execute, or not, all of the non-trivial optimizations. */
83 gate_all_optimizations (void)
86 /* Don't bother doing anything if the program has errors. */
87 && !(errorcount || sorrycount));
90 static struct tree_opt_pass pass_all_optimizations =
93 gate_all_optimizations, /* gate */
97 0, /* static_pass_number */
99 0, /* properties_required */
100 0, /* properties_provided */
101 0, /* properties_destroyed */
102 0, /* todo_flags_start */
103 0, /* todo_flags_finish */
107 /* Pass: cleanup the CFG just before expanding trees to RTL.
108 This is just a round of label cleanups and case node grouping
109 because after the tree optimizers have run such cleanups may
113 execute_cleanup_cfg_post_optimizing (void)
116 cleanup_dead_labels ();
117 group_case_labels ();
120 static struct tree_opt_pass pass_cleanup_cfg_post_optimizing =
122 "final_cleanup", /* name */
124 execute_cleanup_cfg_post_optimizing, /* execute */
127 0, /* static_pass_number */
129 PROP_cfg, /* properties_required */
130 0, /* properties_provided */
131 0, /* properties_destroyed */
132 0, /* todo_flags_start */
133 TODO_dump_func, /* todo_flags_finish */
137 /* Pass: do the actions required to finish with tree-ssa optimization
141 execute_free_datastructures (void)
145 /* ??? This isn't the right place for this. Worse, it got computed
146 more or less at random in various passes. */
147 free_dominance_info (CDI_DOMINATORS);
149 /* Emit gotos for implicit jumps. */
150 disband_implicit_edges ();
152 /* Remove the ssa structures. Do it here since this includes statement
153 annotations that need to be intact during disband_implicit_edges. */
156 /* Re-chain the statements from the blocks. */
157 chain = &DECL_SAVED_TREE (current_function_decl);
158 *chain = alloc_stmt_list ();
160 /* And get rid of annotations we no longer need. */
161 delete_tree_cfg_annotations ();
164 static struct tree_opt_pass pass_free_datastructures =
168 execute_free_datastructures, /* execute */
171 0, /* static_pass_number */
173 PROP_cfg, /* properties_required */
174 0, /* properties_provided */
175 0, /* properties_destroyed */
176 0, /* todo_flags_start */
177 0, /* todo_flags_finish */
182 /* Do the actions required to initialize internal data structures used
183 in tree-ssa optimization passes. */
186 execute_init_datastructures (void)
188 /* Allocate hash tables, arrays and other structures. */
192 static struct tree_opt_pass pass_init_datastructures =
196 execute_init_datastructures, /* execute */
199 0, /* static_pass_number */
201 PROP_cfg, /* properties_required */
202 0, /* properties_provided */
203 0, /* properties_destroyed */
204 0, /* todo_flags_start */
205 0, /* todo_flags_finish */
209 /* Iterate over the pass tree allocating dump file numbers. We want
210 to do this depth first, and independent of whether the pass is
214 register_one_dump_file (struct tree_opt_pass *pass, int n)
216 char *dot_name, *flag_name, *glob_name;
219 /* See below in next_pass_1. */
221 if (pass->static_pass_number != -1)
222 sprintf (num, "%d", ((int) pass->static_pass_number < 0
223 ? 1 : pass->static_pass_number));
225 dot_name = concat (".", pass->name, num, NULL);
226 if (pass->properties_provided & PROP_trees)
228 flag_name = concat ("tree-", pass->name, num, NULL);
229 glob_name = concat ("tree-", pass->name, NULL);
230 pass->static_pass_number = dump_register (dot_name, flag_name, glob_name,
231 TDF_TREE, n + TDI_tree_all, 0);
235 flag_name = concat ("rtl-", pass->name, num, NULL);
236 glob_name = concat ("rtl-", pass->name, NULL);
237 pass->static_pass_number = dump_register (dot_name, flag_name, glob_name,
238 TDF_RTL, n, pass->letter);
243 register_dump_files (struct tree_opt_pass *pass, int properties)
251 pass->properties_required = properties;
253 (properties | pass->properties_provided) & ~pass->properties_destroyed;
255 /* Reset the counter when we reach RTL-based passes. */
256 if ((pass->properties_provided ^ pass->properties_required) & PROP_rtl)
264 new_properties = register_dump_files (pass->sub, new_properties);
266 /* If we have a gate, combine the properties that we could have with
267 and without the pass being examined. */
269 properties &= new_properties;
271 properties = new_properties;
273 pass->properties_provided = properties;
275 register_one_dump_file (pass, pass_number);
284 /* Add a pass to the pass list. Duplicate the pass if it's already
287 static struct tree_opt_pass **
288 next_pass_1 (struct tree_opt_pass **list, struct tree_opt_pass *pass)
291 /* A nonzero static_pass_number indicates that the
292 pass is already in the list. */
293 if (pass->static_pass_number)
295 struct tree_opt_pass *new;
297 new = xmalloc (sizeof (*new));
298 memcpy (new, pass, sizeof (*new));
300 /* Indicate to register_dump_files that this pass has duplicates,
301 and so it should rename the dump file. The first instance will
302 be -1, and be number of duplicates = -static_pass_number - 1.
303 Subsequent instances will be > 0 and just the duplicate number. */
306 pass->static_pass_number -= 1;
307 new->static_pass_number = -pass->static_pass_number;
314 pass->static_pass_number = -1;
318 return &(*list)->next;
322 /* Construct the pass tree. */
325 init_tree_optimization_passes (void)
327 struct tree_opt_pass **p;
329 #define NEXT_PASS(PASS) (p = next_pass_1 (p, &PASS))
332 NEXT_PASS (pass_gimple);
333 NEXT_PASS (pass_remove_useless_stmts);
334 NEXT_PASS (pass_mudflap_1);
335 NEXT_PASS (pass_lower_cf);
336 NEXT_PASS (pass_lower_eh);
337 NEXT_PASS (pass_build_cfg);
338 NEXT_PASS (pass_pre_expand);
339 NEXT_PASS (pass_tree_profile);
340 NEXT_PASS (pass_init_datastructures);
341 NEXT_PASS (pass_all_optimizations);
342 NEXT_PASS (pass_warn_function_return);
343 NEXT_PASS (pass_mudflap_2);
344 NEXT_PASS (pass_free_datastructures);
345 NEXT_PASS (pass_expand);
346 NEXT_PASS (pass_rest_of_compilation);
349 p = &pass_all_optimizations.sub;
350 NEXT_PASS (pass_referenced_vars);
351 NEXT_PASS (pass_create_structure_vars);
352 NEXT_PASS (pass_build_ssa);
353 NEXT_PASS (pass_may_alias);
354 NEXT_PASS (pass_rename_ssa_copies);
355 NEXT_PASS (pass_early_warn_uninitialized);
356 NEXT_PASS (pass_dce);
357 NEXT_PASS (pass_dominator);
358 NEXT_PASS (pass_redundant_phi);
359 NEXT_PASS (pass_dce);
360 NEXT_PASS (pass_merge_phi);
361 NEXT_PASS (pass_forwprop);
362 NEXT_PASS (pass_phiopt);
363 NEXT_PASS (pass_may_alias);
364 NEXT_PASS (pass_tail_recursion);
366 NEXT_PASS (pass_profile);
367 NEXT_PASS (pass_sra);
368 /* FIXME: SRA may generate arbitrary gimple code, exposing new
369 aliased and call-clobbered variables. As mentioned below,
370 pass_may_alias should be a TODO item. */
371 NEXT_PASS (pass_may_alias);
372 NEXT_PASS (pass_rename_ssa_copies);
373 NEXT_PASS (pass_dominator);
374 NEXT_PASS (pass_redundant_phi);
375 NEXT_PASS (pass_dce);
376 NEXT_PASS (pass_dse);
377 NEXT_PASS (pass_may_alias);
378 NEXT_PASS (pass_forwprop);
379 NEXT_PASS (pass_phiopt);
380 NEXT_PASS (pass_ccp);
381 NEXT_PASS (pass_redundant_phi);
382 NEXT_PASS (pass_fold_builtins);
383 /* FIXME: May alias should a TODO but for 4.0.0,
384 we add may_alias right after fold builtins
385 which can create arbitrary GIMPLE. */
386 NEXT_PASS (pass_may_alias);
387 NEXT_PASS (pass_split_crit_edges);
388 NEXT_PASS (pass_pre);
389 NEXT_PASS (pass_sink_code);
390 NEXT_PASS (pass_loop);
391 NEXT_PASS (pass_dominator);
392 NEXT_PASS (pass_redundant_phi);
393 /* FIXME: If DCE is not run before checking for uninitialized uses,
394 we may get false warnings (e.g., testsuite/gcc.dg/uninit-5.c).
395 However, this also causes us to misdiagnose cases that should be
396 real warnings (e.g., testsuite/gcc.dg/pr18501.c).
398 To fix the false positives in uninit-5.c, we would have to
399 account for the predicates protecting the set and the use of each
400 variable. Using a representation like Gated Single Assignment
402 NEXT_PASS (pass_late_warn_uninitialized);
403 NEXT_PASS (pass_cd_dce);
404 NEXT_PASS (pass_dse);
405 NEXT_PASS (pass_forwprop);
406 NEXT_PASS (pass_phiopt);
407 NEXT_PASS (pass_tail_calls);
408 NEXT_PASS (pass_rename_ssa_copies);
409 NEXT_PASS (pass_del_ssa);
410 NEXT_PASS (pass_nrv);
411 NEXT_PASS (pass_remove_useless_vars);
412 NEXT_PASS (pass_mark_used_blocks);
413 NEXT_PASS (pass_cleanup_cfg_post_optimizing);
417 NEXT_PASS (pass_loop_init);
418 NEXT_PASS (pass_lim);
419 NEXT_PASS (pass_unswitch);
420 NEXT_PASS (pass_record_bounds);
421 NEXT_PASS (pass_linear_transform);
422 NEXT_PASS (pass_iv_canon);
423 NEXT_PASS (pass_if_conversion);
424 NEXT_PASS (pass_vectorize);
425 NEXT_PASS (pass_complete_unroll);
426 NEXT_PASS (pass_iv_optimize);
427 NEXT_PASS (pass_loop_done);
432 /* Register the passes with the tree dump code. */
433 register_dump_files (all_passes, 0);
436 static void execute_pass_list (struct tree_opt_pass *);
438 static unsigned int last_verified;
441 execute_todo (int properties, unsigned int flags)
443 if (flags & TODO_rename_vars)
445 rewrite_into_ssa (false);
446 bitmap_clear (vars_to_rename);
448 if (flags & TODO_fix_def_def_chains)
450 rewrite_def_def_chains ();
451 bitmap_clear (vars_to_rename);
454 if (flags & TODO_cleanup_cfg)
457 cleanup_tree_cfg_loop ();
462 if ((flags & TODO_dump_func) && dump_file)
464 if (properties & PROP_trees)
465 dump_function_to_file (current_function_decl,
466 dump_file, dump_flags);
467 else if (properties & PROP_cfg)
468 print_rtl_with_bb (dump_file, get_insns ());
470 print_rtl (dump_file, get_insns ());
472 /* Flush the file. If verification fails, we won't be able to
473 close the file before aborting. */
477 if (flags & TODO_ggc_collect)
480 #ifdef ENABLE_CHECKING
481 if (flags & TODO_verify_ssa)
483 if (flags & TODO_verify_flow)
485 if (flags & TODO_verify_stmts)
491 execute_one_pass (struct tree_opt_pass *pass)
495 /* See if we're supposed to run this pass. */
496 if (pass->gate && !pass->gate ())
499 /* Note that the folders should only create gimple expressions.
500 This is a hack until the new folder is ready. */
501 in_gimple_form = (pass->properties_provided & PROP_trees) != 0;
503 /* Run pre-pass verification. */
504 todo = pass->todo_flags_start & ~last_verified;
506 execute_todo (pass->properties_required, todo);
508 /* If a dump file name is present, open it if enabled. */
509 if (pass->static_pass_number != -1)
511 bool initializing_dump = !dump_initialized_p (pass->static_pass_number);
512 dump_file_name = get_dump_file_name (pass->static_pass_number);
513 dump_file = dump_begin (pass->static_pass_number, &dump_flags);
516 const char *dname, *aname;
517 dname = lang_hooks.decl_printable_name (current_function_decl, 2);
518 aname = (IDENTIFIER_POINTER
519 (DECL_ASSEMBLER_NAME (current_function_decl)));
520 fprintf (dump_file, "\n;; Function %s (%s)%s\n\n", dname, aname,
521 cfun->function_frequency == FUNCTION_FREQUENCY_HOT
523 : cfun->function_frequency == FUNCTION_FREQUENCY_UNLIKELY_EXECUTED
524 ? " (unlikely executed)"
528 if (initializing_dump
529 && graph_dump_format != no_graph
530 && (pass->properties_provided & (PROP_cfg | PROP_rtl))
531 == (PROP_cfg | PROP_rtl))
532 clean_graph_dump_file (dump_file_name);
535 /* If a timevar is present, start it. */
537 timevar_push (pass->tv_id);
545 timevar_pop (pass->tv_id);
548 && (pass->properties_provided & (PROP_cfg | PROP_rtl))
549 == (PROP_cfg | PROP_rtl))
550 print_rtl_with_bb (dump_file, get_insns ());
552 /* Run post-pass cleanup and verification. */
553 todo = pass->todo_flags_finish;
554 last_verified = todo & TODO_verify_all;
556 execute_todo (pass->properties_provided, todo);
558 /* Flush and close dump file. */
561 free ((char *) dump_file_name);
562 dump_file_name = NULL;
566 dump_end (pass->static_pass_number, dump_file);
574 execute_pass_list (struct tree_opt_pass *pass)
578 if (execute_one_pass (pass) && pass->sub)
579 execute_pass_list (pass->sub);
586 /* Update recursively all inlined_to pointers of functions
587 inlined into NODE to INLINED_TO. */
589 update_inlined_to_pointers (struct cgraph_node *node,
590 struct cgraph_node *inlined_to)
592 struct cgraph_edge *e;
593 for (e = node->callees; e; e = e->next_callee)
595 if (e->callee->global.inlined_to)
597 e->callee->global.inlined_to = inlined_to;
598 update_inlined_to_pointers (e->callee, inlined_to);
604 /* For functions-as-trees languages, this performs all optimization and
605 compilation for FNDECL. */
608 tree_rest_of_compilation (tree fndecl)
610 location_t saved_loc;
611 struct cgraph_node *saved_node = NULL, *node;
613 timevar_push (TV_EXPAND);
615 gcc_assert (!flag_unit_at_a_time || cgraph_global_info_ready);
617 /* Initialize the RTL code for the function. */
618 current_function_decl = fndecl;
619 saved_loc = input_location;
620 input_location = DECL_SOURCE_LOCATION (fndecl);
621 init_function_start (fndecl);
623 /* Even though we're inside a function body, we still don't want to
624 call expand_expr to calculate the size of a variable-sized array.
625 We haven't necessarily assigned RTL to all variables yet, so it's
626 not safe to try to expand expressions involving them. */
627 cfun->x_dont_save_pending_sizes_p = 1;
629 node = cgraph_node (fndecl);
631 /* We might need the body of this function so that we can expand
632 it inline somewhere else. This means not lowering some constructs
633 such as exception handling. */
634 if (cgraph_preserve_function_body_p (fndecl))
636 if (!flag_unit_at_a_time)
638 struct cgraph_edge *e;
640 saved_node = cgraph_clone_node (node);
641 for (e = saved_node->callees; e; e = e->next_callee)
642 if (!e->inline_failed)
643 cgraph_clone_inlined_nodes (e, true);
645 cfun->saved_static_chain_decl = cfun->static_chain_decl;
646 cfun->saved_tree = save_body (fndecl, &cfun->saved_args,
647 &cfun->saved_static_chain_decl);
650 if (flag_inline_trees)
652 struct cgraph_edge *e;
653 for (e = node->callees; e; e = e->next_callee)
654 if (!e->inline_failed || warn_inline)
658 timevar_push (TV_INTEGRATION);
659 optimize_inline_calls (fndecl);
660 timevar_pop (TV_INTEGRATION);
664 /* We are not going to maintain the cgraph edges up to date.
665 Kill it so it won't confuse us. */
666 cgraph_node_remove_callees (node);
669 /* Initialize the default bitmap obstack. */
670 bitmap_obstack_initialize (NULL);
671 bitmap_obstack_initialize (®_obstack); /* FIXME, only at RTL generation*/
673 vars_to_rename = BITMAP_ALLOC (NULL);
675 /* Perform all tree transforms and optimizations. */
676 execute_pass_list (all_passes);
678 bitmap_obstack_release (®_obstack);
680 /* Release the default bitmap obstack. */
681 bitmap_obstack_release (NULL);
683 /* Restore original body if still needed. */
684 if (cfun->saved_tree)
686 DECL_SAVED_TREE (fndecl) = cfun->saved_tree;
687 DECL_ARGUMENTS (fndecl) = cfun->saved_args;
688 cfun->static_chain_decl = cfun->saved_static_chain_decl;
690 /* When not in unit-at-a-time mode, we must preserve out of line copy
691 representing node before inlining. Restore original outgoing edges
692 using clone we created earlier. */
693 if (!flag_unit_at_a_time)
695 struct cgraph_edge *e;
697 cgraph_node_remove_callees (node);
698 node->callees = saved_node->callees;
699 saved_node->callees = NULL;
700 update_inlined_to_pointers (node, node);
701 for (e = node->callees; e; e = e->next_callee)
703 cgraph_remove_node (saved_node);
707 DECL_SAVED_TREE (fndecl) = NULL;
710 /* If requested, warn about function definitions where the function will
711 return a value (usually of some struct or union type) which itself will
712 take up a lot of stack space. */
713 if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))
715 tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));
717 if (ret_type && TYPE_SIZE_UNIT (ret_type)
718 && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST
719 && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),
722 unsigned int size_as_int
723 = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));
725 if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)
726 warning ("%Jsize of return value of %qD is %u bytes",
727 fndecl, fndecl, size_as_int);
729 warning ("%Jsize of return value of %qD is larger than %wd bytes",
730 fndecl, fndecl, larger_than_size);
734 if (!flag_inline_trees)
736 DECL_SAVED_TREE (fndecl) = NULL;
737 if (DECL_STRUCT_FUNCTION (fndecl) == 0
738 && !cgraph_node (fndecl)->origin)
740 /* Stop pointing to the local nodes about to be freed.
741 But DECL_INITIAL must remain nonzero so we know this
742 was an actual function definition.
743 For a nested function, this is done in c_pop_function_context.
744 If rest_of_compilation set this to 0, leave it 0. */
745 if (DECL_INITIAL (fndecl) != 0)
746 DECL_INITIAL (fndecl) = error_mark_node;
750 input_location = saved_loc;
753 timevar_pop (TV_EXPAND);