1 /* Top-level control of tree optimizations.
2 Copyright 2001, 2002, 2003, 2004 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"
47 #include "tree-alias-common.h"
52 /* Global variables used to communicate with passes. */
54 bitmap vars_to_rename;
57 /* The root of the compilation pass tree, once constructed. */
58 static struct tree_opt_pass *all_passes;
60 /* Pass: dump the gimplified, inlined, functions. */
62 static struct tree_opt_pass pass_gimple =
69 0, /* static_pass_number */
71 0, /* properties_required */
72 PROP_gimple_any, /* properties_provided */
73 0, /* properties_destroyed */
74 0, /* todo_flags_start */
75 TODO_dump_func /* todo_flags_finish */
78 /* Gate: execute, or not, all of the non-trivial optimizations. */
81 gate_all_optimizations (void)
84 /* Don't bother doing anything if the program has errors. */
85 && !(errorcount || sorrycount));
88 static struct tree_opt_pass pass_all_optimizations =
91 gate_all_optimizations, /* gate */
95 0, /* static_pass_number */
97 0, /* properties_required */
98 0, /* properties_provided */
99 0, /* properties_destroyed */
100 0, /* todo_flags_start */
101 0 /* todo_flags_finish */
104 /* Pass: cleanup the CFG just before expanding trees to RTL.
105 This is just a round of label cleanups and case node grouping
106 because after the tree optimizers have run such cleanups may
110 execute_cleanup_cfg_post_optimizing (void)
113 cleanup_dead_labels ();
114 group_case_labels ();
117 static struct tree_opt_pass pass_cleanup_cfg_post_optimizing =
121 execute_cleanup_cfg_post_optimizing, /* execute */
124 0, /* static_pass_number */
126 PROP_cfg, /* properties_required */
127 0, /* properties_provided */
128 0, /* properties_destroyed */
129 0, /* todo_flags_start */
130 0 /* todo_flags_finish */
133 /* Pass: do the actions required to finish with tree-ssa optimization
137 execute_free_datastructures (void)
141 /* ??? This isn't the right place for this. Worse, it got computed
142 more or less at random in various passes. */
143 free_dominance_info (CDI_DOMINATORS);
145 /* Emit gotos for implicit jumps. */
146 disband_implicit_edges ();
148 /* Remove the ssa structures. Do it here since this includes statement
149 annotations that need to be intact during disband_implicit_edges. */
152 /* Re-chain the statements from the blocks. */
153 chain = &DECL_SAVED_TREE (current_function_decl);
154 *chain = alloc_stmt_list ();
156 /* And get rid of annotations we no longer need. */
157 delete_tree_cfg_annotations ();
160 static struct tree_opt_pass pass_free_datastructures =
164 execute_free_datastructures, /* execute */
167 0, /* static_pass_number */
169 PROP_cfg, /* properties_required */
170 0, /* properties_provided */
171 0, /* properties_destroyed */
172 0, /* todo_flags_start */
173 0 /* todo_flags_finish */
177 /* Do the actions required to initialize internal data structures used
178 in tree-ssa optimization passes. */
181 execute_init_datastructures (void)
183 /* Allocate hash tables, arrays and other structures. */
187 static struct tree_opt_pass pass_init_datastructures =
191 execute_init_datastructures, /* execute */
194 0, /* static_pass_number */
196 PROP_cfg, /* properties_required */
197 0, /* properties_provided */
198 0, /* properties_destroyed */
199 0, /* todo_flags_start */
200 0 /* todo_flags_finish */
203 /* Iterate over the pass tree allocating dump file numbers. We want
204 to do this depth first, and independent of whether the pass is
208 register_one_dump_file (struct tree_opt_pass *pass)
210 char *dot_name, *flag_name;
216 /* See below in dup_pass_1. */
218 if (pass->static_pass_number)
219 sprintf (num, "%d", ((int) pass->static_pass_number < 0
220 ? 1 : pass->static_pass_number));
222 dot_name = concat (".", pass->name, num, NULL);
223 flag_name = concat ("tree-", pass->name, num, NULL);
225 pass->static_pass_number = dump_register (dot_name, flag_name);
229 register_dump_files (struct tree_opt_pass *pass, int properties)
233 /* Verify that all required properties are present. */
234 if (pass->properties_required & ~properties)
237 if (pass->properties_destroyed & pass->properties_provided)
240 pass->properties_required = properties;
241 pass->properties_provided = properties =
242 (properties | pass->properties_provided) & ~pass->properties_destroyed;
244 if (properties & PROP_trees)
245 register_one_dump_file (pass);
247 properties = register_dump_files (pass->sub, properties);
255 /* Duplicate a pass that's to be run more than once. */
257 static struct tree_opt_pass *
258 dup_pass_1 (struct tree_opt_pass *pass)
260 struct tree_opt_pass *new;
262 new = xmalloc (sizeof (*new));
263 memcpy (new, pass, sizeof (*new));
265 /* Indicate to register_dump_files that this pass has duplicates,
266 and so it should rename the dump file. The first instance will
267 be < 0, and be number of duplicates = -static_pass_number + 1.
268 Subsequent instances will be > 0 and just the duplicate number. */
271 int n, p = pass->static_pass_number;
278 pass->static_pass_number = p;
279 new->static_pass_number = n;
285 /* Construct the pass tree. */
288 init_tree_optimization_passes (void)
290 struct tree_opt_pass **p;
292 #define NEXT_PASS(PASS) (*p = &PASS, p = &(*p)->next)
293 #define DUP_PASS(PASS) (*dup_pass_1 (&PASS))
296 NEXT_PASS (pass_gimple);
297 NEXT_PASS (pass_remove_useless_stmts);
298 NEXT_PASS (pass_mudflap_1);
299 NEXT_PASS (pass_lower_cf);
300 NEXT_PASS (pass_lower_eh);
301 NEXT_PASS (pass_build_cfg);
302 NEXT_PASS (pass_tree_profile);
303 NEXT_PASS (pass_init_datastructures);
304 NEXT_PASS (pass_all_optimizations);
305 NEXT_PASS (pass_warn_function_return);
306 NEXT_PASS (pass_mudflap_2);
307 NEXT_PASS (pass_free_datastructures);
308 NEXT_PASS (pass_expand);
309 NEXT_PASS (pass_rest_of_compilation);
312 p = &pass_all_optimizations.sub;
313 NEXT_PASS (pass_referenced_vars);
314 NEXT_PASS (pass_build_pta);
315 NEXT_PASS (pass_build_ssa);
316 NEXT_PASS (pass_rename_ssa_copies);
317 NEXT_PASS (pass_early_warn_uninitialized);
318 NEXT_PASS (pass_dce);
319 NEXT_PASS (pass_dominator);
320 NEXT_PASS (pass_redundant_phi);
321 NEXT_PASS (DUP_PASS (pass_dce));
322 NEXT_PASS (pass_forwprop);
323 NEXT_PASS (pass_phiopt);
324 NEXT_PASS (pass_may_alias);
325 NEXT_PASS (pass_tail_recursion);
327 NEXT_PASS (pass_profile);
328 NEXT_PASS (pass_lower_complex);
329 NEXT_PASS (pass_sra);
330 NEXT_PASS (DUP_PASS (pass_rename_ssa_copies));
331 NEXT_PASS (DUP_PASS (pass_dominator));
332 NEXT_PASS (DUP_PASS (pass_redundant_phi));
333 NEXT_PASS (DUP_PASS (pass_dce));
334 NEXT_PASS (pass_dse);
335 NEXT_PASS (DUP_PASS (pass_may_alias));
336 NEXT_PASS (DUP_PASS (pass_forwprop));
337 NEXT_PASS (DUP_PASS (pass_phiopt));
338 NEXT_PASS (pass_ccp);
339 NEXT_PASS (DUP_PASS (pass_redundant_phi));
340 NEXT_PASS (pass_fold_builtins);
341 NEXT_PASS (pass_split_crit_edges);
342 NEXT_PASS (pass_pre);
343 NEXT_PASS (pass_loop);
344 NEXT_PASS (DUP_PASS (pass_dominator));
345 NEXT_PASS (DUP_PASS (pass_redundant_phi));
346 NEXT_PASS (pass_cd_dce);
347 NEXT_PASS (DUP_PASS (pass_dse));
348 NEXT_PASS (DUP_PASS (pass_forwprop));
349 NEXT_PASS (DUP_PASS (pass_phiopt));
350 NEXT_PASS (pass_tail_calls);
351 NEXT_PASS (pass_late_warn_uninitialized);
352 NEXT_PASS (pass_del_pta);
353 NEXT_PASS (pass_del_ssa);
354 NEXT_PASS (pass_nrv);
355 NEXT_PASS (pass_remove_useless_vars);
356 NEXT_PASS (pass_cleanup_cfg_post_optimizing);
360 NEXT_PASS (pass_loop_init);
361 NEXT_PASS (pass_lim);
362 NEXT_PASS (pass_loop_done);
368 /* Register the passes with the tree dump code. */
369 register_dump_files (all_passes, 0);
372 static void execute_pass_list (struct tree_opt_pass *);
374 static unsigned int last_verified;
377 execute_todo (unsigned int flags)
379 if (flags & TODO_rename_vars)
381 rewrite_into_ssa (false);
382 bitmap_clear (vars_to_rename);
385 if ((flags & TODO_dump_func) && dump_file)
387 dump_function_to_file (current_function_decl,
388 dump_file, dump_flags);
390 /* Flush the file. If verification fails, we won't be able to
391 close the file before aborting. */
395 if (flags & TODO_ggc_collect)
398 #ifdef ENABLE_CHECKING
399 if (flags & TODO_verify_ssa)
401 if (flags & TODO_verify_flow)
403 if (flags & TODO_verify_stmts)
409 execute_one_pass (struct tree_opt_pass *pass)
413 /* See if we're supposed to run this pass. */
414 if (pass->gate && !pass->gate ())
417 /* Note that the folders should only create gimple expressions.
418 This is a hack until the new folder is ready. */
419 in_gimple_form = (pass->properties_provided & PROP_trees) != 0;
421 /* Run pre-pass verification. */
422 todo = pass->todo_flags_start & ~last_verified;
426 /* If a dump file name is present, open it if enabled. */
427 if (pass->static_pass_number)
429 dump_file = dump_begin (pass->static_pass_number, &dump_flags);
432 const char *dname, *aname;
433 dname = lang_hooks.decl_printable_name (current_function_decl, 2);
434 aname = (IDENTIFIER_POINTER
435 (DECL_ASSEMBLER_NAME (current_function_decl)));
436 fprintf (dump_file, "\n;; Function %s (%s)\n\n", dname, aname);
440 /* If a timevar is present, start it. */
442 timevar_push (pass->tv_id);
448 /* Run post-pass cleanup and verification. */
449 todo = pass->todo_flags_finish;
450 last_verified = todo & TODO_verify_all;
454 /* Close down timevar and dump file. */
456 timevar_pop (pass->tv_id);
459 dump_end (pass->static_pass_number, dump_file);
467 execute_pass_list (struct tree_opt_pass *pass)
471 if (execute_one_pass (pass) && pass->sub)
472 execute_pass_list (pass->sub);
479 /* For functions-as-trees languages, this performs all optimization and
480 compilation for FNDECL. */
483 tree_rest_of_compilation (tree fndecl, bool nested_p)
485 location_t saved_loc;
486 struct cgraph_node *saved_node = NULL, *node;
488 timevar_push (TV_EXPAND);
490 if (flag_unit_at_a_time && !cgraph_global_info_ready)
493 /* Initialize the RTL code for the function. */
494 current_function_decl = fndecl;
495 saved_loc = input_location;
496 input_location = DECL_SOURCE_LOCATION (fndecl);
497 init_function_start (fndecl);
499 /* Even though we're inside a function body, we still don't want to
500 call expand_expr to calculate the size of a variable-sized array.
501 We haven't necessarily assigned RTL to all variables yet, so it's
502 not safe to try to expand expressions involving them. */
503 cfun->x_dont_save_pending_sizes_p = 1;
505 node = cgraph_node (fndecl);
507 /* We might need the body of this function so that we can expand
508 it inline somewhere else. This means not lowering some constructs
509 such as exception handling. */
510 if (cgraph_preserve_function_body_p (fndecl))
512 if (!flag_unit_at_a_time)
514 struct cgraph_edge *e;
516 saved_node = cgraph_clone_node (node);
517 for (e = saved_node->callees; e; e = e->next_callee)
518 if (!e->inline_failed)
519 cgraph_clone_inlined_nodes (e, true);
521 cfun->saved_tree = save_body (fndecl, &cfun->saved_args);
524 if (flag_inline_trees)
526 struct cgraph_edge *e;
527 for (e = node->callees; e; e = e->next_callee)
528 if (!e->inline_failed || warn_inline)
532 timevar_push (TV_INTEGRATION);
533 optimize_inline_calls (fndecl);
534 timevar_pop (TV_INTEGRATION);
539 vars_to_rename = BITMAP_XMALLOC ();
541 /* If this is a nested function, protect the local variables in the stack
542 above us from being collected while we're compiling this function. */
546 /* Perform all tree transforms and optimizations. */
547 execute_pass_list (all_passes);
549 /* Restore original body if still needed. */
550 if (cfun->saved_tree)
552 DECL_SAVED_TREE (fndecl) = cfun->saved_tree;
553 DECL_ARGUMENTS (fndecl) = cfun->saved_args;
555 /* When not in unit-at-a-time mode, we must preserve out of line copy
556 representing node before inlining. Restore original outgoing edges
557 using clone we created earlier. */
558 if (!flag_unit_at_a_time)
560 struct cgraph_edge *e;
561 while (node->callees)
562 cgraph_remove_edge (node->callees);
563 node->callees = saved_node->callees;
564 saved_node->callees = NULL;
565 for (e = saved_node->callees; e; e = e->next_callee)
567 cgraph_remove_node (saved_node);
571 DECL_SAVED_TREE (fndecl) = NULL;
574 /* If requested, warn about function definitions where the function will
575 return a value (usually of some struct or union type) which itself will
576 take up a lot of stack space. */
577 if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))
579 tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));
581 if (ret_type && TYPE_SIZE_UNIT (ret_type)
582 && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST
583 && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),
586 unsigned int size_as_int
587 = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));
589 if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)
590 warning ("%Jsize of return value of '%D' is %u bytes",
591 fndecl, fndecl, size_as_int);
593 warning ("%Jsize of return value of '%D' is larger than %wd bytes",
594 fndecl, fndecl, larger_than_size);
598 if (!nested_p && !flag_inline_trees)
600 DECL_SAVED_TREE (fndecl) = NULL;
601 if (DECL_STRUCT_FUNCTION (fndecl) == 0
602 && !cgraph_node (fndecl)->origin)
604 /* Stop pointing to the local nodes about to be freed.
605 But DECL_INITIAL must remain nonzero so we know this
606 was an actual function definition.
607 For a nested function, this is done in c_pop_function_context.
608 If rest_of_compilation set this to 0, leave it 0. */
609 if (DECL_INITIAL (fndecl) != 0)
610 DECL_INITIAL (fndecl) = error_mark_node;
614 input_location = saved_loc;
618 /* Undo the GC context switch. */
621 timevar_pop (TV_EXPAND);