1 /* Top-level LTO routines.
2 Copyright (C) 2009-2022 Free Software Foundation, Inc.
3 Contributed by CodeSourcery, Inc.
5 This file is part of GCC.
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
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
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/>. */
23 #include "coretypes.h"
27 #include "basic-block.h"
31 #include "alloc-pool.h"
32 #include "tree-pass.h"
33 #include "tree-streamer.h"
37 #include "stor-layout.h"
38 #include "symbol-summary.h"
43 #include "lto-section-names.h"
44 #include "splay-tree.h"
45 #include "lto-partition.h"
47 #include "pass_manager.h"
48 #include "ipa-fnsummary.h"
49 #include "ipa-utils.h"
50 #include "gomp-constants.h"
51 #include "lto-symtab.h"
52 #include "stringpool.h"
53 #include "fold-const.h"
56 #include "lto-common.h"
59 /* Number of parallel tasks to run, -1 if we want to use GNU Make jobserver. */
60 static int lto_parallelism
;
62 /* Return true when NODE has a clone that is analyzed (i.e. we need
63 to load its body even if the node itself is not needed). */
66 has_analyzed_clone_p (struct cgraph_node
*node
)
68 struct cgraph_node
*orig
= node
;
77 else if (node
->next_sibling_clone
)
78 node
= node
->next_sibling_clone
;
81 while (node
!= orig
&& !node
->next_sibling_clone
)
82 node
= node
->clone_of
;
84 node
= node
->next_sibling_clone
;
90 /* Read the function body for the function associated with NODE. */
93 lto_materialize_function (struct cgraph_node
*node
)
98 /* Read in functions with body (analyzed nodes)
99 and also functions that are needed to produce virtual clones. */
100 if ((node
->has_gimple_body_p () && node
->analyzed
)
101 || node
->used_as_abstract_origin
102 || has_analyzed_clone_p (node
))
104 /* Clones don't need to be read. */
107 if (DECL_FUNCTION_PERSONALITY (decl
) && !first_personality_decl
)
108 first_personality_decl
= DECL_FUNCTION_PERSONALITY (decl
);
109 /* If the file contains a function with a language specific EH
110 personality set or with EH enabled initialize the backend EH
112 if (DECL_FUNCTION_PERSONALITY (decl
)
113 || opt_for_fn (decl
, flag_exceptions
))
117 /* Let the middle end know about the function. */
118 rest_of_decl_compilation (decl
, 1, 0);
121 /* Materialize all the bodies for all the nodes in the callgraph. */
124 materialize_cgraph (void)
126 struct cgraph_node
*node
;
127 timevar_id_t lto_timer
;
131 flag_wpa
? "Materializing decls:" : "Reading function bodies:");
134 FOR_EACH_FUNCTION (node
)
136 if (node
->lto_file_data
)
138 lto_materialize_function (node
);
139 lto_stats
.num_input_cgraph_nodes
++;
144 /* Start the appropriate timer depending on the mode that we are
146 lto_timer
= (flag_wpa
) ? TV_WHOPR_WPA
147 : (flag_ltrans
) ? TV_WHOPR_LTRANS
149 timevar_push (lto_timer
);
151 current_function_decl
= NULL
;
155 fprintf (stderr
, "\n");
157 timevar_pop (lto_timer
);
160 /* Actually stream out ENCODER into TEMP_FILENAME. */
163 stream_out (char *temp_filename
, lto_symtab_encoder_t encoder
, int part
)
165 lto_file
*file
= lto_obj_file_open (temp_filename
, true);
167 fatal_error (input_location
, "%<lto_obj_file_open()%> failed");
168 lto_set_current_out_file (file
);
170 gcc_assert (!dump_file
);
171 streamer_dump_file
= dump_begin (TDI_lto_stream_out
, NULL
, part
);
172 ipa_write_optimization_summaries (encoder
);
174 free (CONST_CAST (char *, file
->filename
));
176 lto_set_current_out_file (NULL
);
177 lto_obj_file_close (file
);
179 if (streamer_dump_file
)
181 dump_end (TDI_lto_stream_out
, streamer_dump_file
);
182 streamer_dump_file
= NULL
;
186 /* Wait for forked process and signal errors. */
187 #ifdef HAVE_WORKING_FORK
197 int w
= waitpid (0, &status
, WUNTRACED
| WCONTINUED
);
199 fatal_error (input_location
, "waitpid failed");
201 if (WIFEXITED (status
) && WEXITSTATUS (status
))
202 fatal_error (input_location
, "streaming subprocess failed");
203 else if (WIFSIGNALED (status
))
204 fatal_error (input_location
,
205 "streaming subprocess was killed by signal");
207 while (!WIFEXITED (status
) && !WIFSIGNALED (status
));
212 stream_out_partitions_1 (char *temp_filename
, int blen
, int min
, int max
)
214 /* Write all the nodes in SET. */
215 for (int p
= min
; p
< max
; p
++)
217 sprintf (temp_filename
+ blen
, "%u.o", p
);
218 stream_out (temp_filename
, ltrans_partitions
[p
]->encoder
, p
);
219 ltrans_partitions
[p
]->encoder
= NULL
;
223 /* Stream out ENCODER into TEMP_FILENAME
224 Fork if that seems to help. */
227 stream_out_partitions (char *temp_filename
, int blen
, int min
, int max
,
228 bool ARG_UNUSED (last
))
230 #ifdef HAVE_WORKING_FORK
233 if (lto_parallelism
<= 1)
235 stream_out_partitions_1 (temp_filename
, blen
, min
, max
);
239 /* Do not run more than LTO_PARALLELISM streamings
240 FIXME: we ignore limits on jobserver. */
241 if (lto_parallelism
> 0 && nruns
>= lto_parallelism
)
246 /* If this is not the last parallel partition, execute new
247 streaming process. */
250 pid_t cpid
= fork ();
254 setproctitle ("lto1-wpa-streaming");
255 stream_out_partitions_1 (temp_filename
, blen
, min
, max
);
258 /* Fork failed; lets do the job ourseleves. */
260 stream_out_partitions_1 (temp_filename
, blen
, min
, max
);
264 /* Last partition; stream it and wait for all children to die. */
268 stream_out_partitions_1 (temp_filename
, blen
, min
, max
);
269 for (i
= 0; i
< nruns
; i
++)
272 asm_nodes_output
= true;
274 stream_out_partitions_1 (temp_filename
, blen
, min
, max
);
278 /* Write all output files in WPA mode and the file with the list of
282 lto_wpa_write_files (void)
285 ltrans_partition part
;
286 FILE *ltrans_output_list_stream
;
288 auto_vec
<char *>temp_filenames
;
289 auto_vec
<int>temp_priority
;
292 /* Open the LTRANS output list. */
293 if (!ltrans_output_list
)
294 fatal_error (input_location
, "no LTRANS output list filename provided");
296 timevar_push (TV_WHOPR_WPA
);
298 FOR_EACH_VEC_ELT (ltrans_partitions
, i
, part
)
299 lto_stats
.num_output_symtab_nodes
300 += lto_symtab_encoder_size (part
->encoder
);
302 timevar_pop (TV_WHOPR_WPA
);
304 timevar_push (TV_WHOPR_WPA_IO
);
307 /* Do body modifications needed for streaming before we fork out
309 FOR_EACH_FUNCTION (node
)
310 if (!node
->clone_of
&& gimple_has_body_p (node
->decl
))
311 lto_prepare_function_for_streaming (node
);
314 report_heap_memory_use ();
316 /* Generate a prefix for the LTRANS unit files. */
317 blen
= strlen (ltrans_output_list
);
318 temp_filename
= (char *) xmalloc (blen
+ sizeof ("2147483648.o"));
319 strcpy (temp_filename
, ltrans_output_list
);
320 if (blen
> sizeof (".out")
321 && strcmp (temp_filename
+ blen
- sizeof (".out") + 1,
323 temp_filename
[blen
- sizeof (".out") + 1] = '\0';
324 blen
= strlen (temp_filename
);
326 n_sets
= ltrans_partitions
.length ();
327 unsigned sets_per_worker
= n_sets
;
328 if (lto_parallelism
> 1)
330 if (lto_parallelism
> (int)n_sets
)
331 lto_parallelism
= n_sets
;
332 sets_per_worker
= (n_sets
+ lto_parallelism
- 1) / lto_parallelism
;
335 for (i
= 0; i
< n_sets
; i
++)
337 ltrans_partition part
= ltrans_partitions
[i
];
339 /* Write all the nodes in SET. */
340 sprintf (temp_filename
+ blen
, "%u.o", i
);
343 fprintf (stderr
, " %s (%s %i insns)", temp_filename
, part
->name
,
345 if (symtab
->dump_file
)
347 lto_symtab_encoder_iterator lsei
;
349 fprintf (symtab
->dump_file
,
350 "Writing partition %s to file %s, %i insns\n",
351 part
->name
, temp_filename
, part
->insns
);
352 fprintf (symtab
->dump_file
, " Symbols in partition: ");
353 for (lsei
= lsei_start_in_partition (part
->encoder
);
355 lsei_next_in_partition (&lsei
))
357 symtab_node
*node
= lsei_node (lsei
);
358 fprintf (symtab
->dump_file
, "%s ", node
->dump_asm_name ());
360 fprintf (symtab
->dump_file
, "\n Symbols in boundary: ");
361 for (lsei
= lsei_start (part
->encoder
); !lsei_end_p (lsei
);
364 symtab_node
*node
= lsei_node (lsei
);
365 if (!lto_symtab_encoder_in_partition_p (part
->encoder
, node
))
367 fprintf (symtab
->dump_file
, "%s ", node
->dump_asm_name ());
368 cgraph_node
*cnode
= dyn_cast
<cgraph_node
*> (node
);
370 && lto_symtab_encoder_encode_body_p (part
->encoder
,
372 fprintf (symtab
->dump_file
, "(body included)");
375 varpool_node
*vnode
= dyn_cast
<varpool_node
*> (node
);
377 && lto_symtab_encoder_encode_initializer_p (part
->encoder
,
379 fprintf (symtab
->dump_file
, "(initializer included)");
383 fprintf (symtab
->dump_file
, "\n");
385 gcc_checking_assert (lto_symtab_encoder_size (part
->encoder
) || !i
);
387 temp_priority
.safe_push (part
->insns
);
388 temp_filenames
.safe_push (xstrdup (temp_filename
));
390 memory_block_pool::trim (0);
392 for (int set
= 0; set
< MAX (lto_parallelism
, 1); set
++)
394 stream_out_partitions (temp_filename
, blen
, set
* sets_per_worker
,
395 MIN ((set
+ 1) * sets_per_worker
, n_sets
),
396 set
== MAX (lto_parallelism
, 1) - 1);
399 ltrans_output_list_stream
= fopen (ltrans_output_list
, "w");
400 if (ltrans_output_list_stream
== NULL
)
401 fatal_error (input_location
,
402 "opening LTRANS output list %s: %m", ltrans_output_list
);
403 for (i
= 0; i
< n_sets
; i
++)
405 unsigned int len
= strlen (temp_filenames
[i
]);
406 if (fprintf (ltrans_output_list_stream
, "%i\n", temp_priority
[i
]) < 0
407 || fwrite (temp_filenames
[i
], 1, len
, ltrans_output_list_stream
) < len
408 || fwrite ("\n", 1, 1, ltrans_output_list_stream
) < 1)
409 fatal_error (input_location
, "writing to LTRANS output list %s: %m",
411 free (temp_filenames
[i
]);
414 lto_stats
.num_output_files
+= n_sets
;
416 /* Close the LTRANS output list. */
417 if (fclose (ltrans_output_list_stream
))
418 fatal_error (input_location
,
419 "closing LTRANS output list %s: %m", ltrans_output_list
);
421 free_ltrans_partitions ();
422 free (temp_filename
);
424 timevar_pop (TV_WHOPR_WPA_IO
);
427 /* Perform whole program analysis (WPA) on the callgraph and write out the
428 optimization plan. */
431 do_whole_program_analysis (void)
437 /* TODO: jobserver communication is not supported, yet. */
438 if (!strcmp (flag_wpa
, "jobserver"))
439 lto_parallelism
= param_max_lto_streaming_parallelism
;
442 lto_parallelism
= atoi (flag_wpa
);
443 if (lto_parallelism
<= 0)
445 if (lto_parallelism
>= param_max_lto_streaming_parallelism
)
446 lto_parallelism
= param_max_lto_streaming_parallelism
;
449 timevar_start (TV_PHASE_OPT_GEN
);
451 /* Note that since we are in WPA mode, materialize_cgraph will not
452 actually read in all the function bodies. It only materializes
453 the decls and cgraph nodes so that analysis can be performed. */
454 materialize_cgraph ();
456 /* Reading in the cgraph uses different timers, start timing WPA now. */
457 timevar_push (TV_WHOPR_WPA
);
459 if (pre_ipa_mem_report
)
460 dump_memory_report ("Memory consumption before IPA");
462 symtab
->function_flags_ready
= true;
464 if (symtab
->dump_file
)
465 symtab
->dump (symtab
->dump_file
);
466 bitmap_obstack_initialize (NULL
);
467 symtab
->state
= IPA_SSA
;
469 execute_ipa_pass_list (g
->get_passes ()->all_regular_ipa_passes
);
471 /* When WPA analysis raises errors, do not bother to output anything. */
475 /* We are about to launch the final LTRANS phase, stop the WPA timer. */
476 timevar_pop (TV_WHOPR_WPA
);
478 /* We are no longer going to stream in anything. Free some memory. */
479 lto_free_file_name_hash ();
482 timevar_push (TV_WHOPR_PARTITIONING
);
484 gcc_assert (!dump_file
);
485 dump_file
= dump_begin (partition_dump_id
, NULL
);
488 symtab
->dump (dump_file
);
490 symtab_node::checking_verify_symtab_nodes ();
491 bitmap_obstack_release (NULL
);
492 if (flag_lto_partition
== LTO_PARTITION_1TO1
)
494 else if (flag_lto_partition
== LTO_PARTITION_MAX
)
496 else if (flag_lto_partition
== LTO_PARTITION_ONE
)
497 lto_balanced_map (1, INT_MAX
);
498 else if (flag_lto_partition
== LTO_PARTITION_BALANCED
)
499 lto_balanced_map (param_lto_partitions
,
500 param_max_partition_size
);
504 /* Size summaries are needed for balanced partitioning. Free them now so
505 the memory can be used for streamer caches. */
506 ipa_free_size_summary ();
508 /* AUX pointers are used by partitioning code to bookkeep number of
509 partitions symbol is in. This is no longer needed. */
510 FOR_EACH_SYMBOL (node
)
513 lto_stats
.num_cgraph_partitions
+= ltrans_partitions
.length ();
515 /* Find out statics that need to be promoted
516 to globals with hidden visibility because they are accessed from multiple
518 lto_promote_cross_file_statics ();
520 dump_end (partition_dump_id
, dump_file
);
522 timevar_pop (TV_WHOPR_PARTITIONING
);
524 timevar_stop (TV_PHASE_OPT_GEN
);
526 /* Collect a last time - in lto_wpa_write_files we may end up forking
527 with the idea that this doesn't increase memory usage. So we
528 absoultely do not want to collect after that. */
531 timevar_start (TV_PHASE_STREAM_OUT
);
534 fprintf (stderr
, "\nStreaming out");
537 lto_wpa_write_files ();
539 fprintf (stderr
, "\n");
540 timevar_stop (TV_PHASE_STREAM_OUT
);
542 if (post_ipa_mem_report
)
543 dump_memory_report ("Memory consumption after IPA");
545 /* Show the LTO report before launching LTRANS. */
546 if (flag_lto_report
|| (flag_wpa
&& flag_lto_report_wpa
))
547 print_lto_report_1 ();
549 dump_memory_report ("Final");
552 /* Create artificial pointers for "omp declare target link" vars. */
555 offload_handle_link_vars (void)
557 #ifdef ACCEL_COMPILER
559 FOR_EACH_VARIABLE (var
)
560 if (lookup_attribute ("omp declare target link",
561 DECL_ATTRIBUTES (var
->decl
)))
563 tree type
= build_pointer_type (TREE_TYPE (var
->decl
));
564 tree link_ptr_var
= build_decl (UNKNOWN_LOCATION
, VAR_DECL
,
565 clone_function_name (var
->decl
,
567 TREE_USED (link_ptr_var
) = 1;
568 TREE_STATIC (link_ptr_var
) = 1;
569 TREE_PUBLIC (link_ptr_var
) = TREE_PUBLIC (var
->decl
);
570 DECL_ARTIFICIAL (link_ptr_var
) = 1;
571 SET_DECL_ASSEMBLER_NAME (link_ptr_var
, DECL_NAME (link_ptr_var
));
572 SET_DECL_VALUE_EXPR (var
->decl
, build_simple_mem_ref (link_ptr_var
));
573 DECL_HAS_VALUE_EXPR_P (var
->decl
) = 1;
579 lto_option_lang_mask (void)
584 /* Main entry point for the GIMPLE front end. This front end has
585 three main personalities:
587 - LTO (-flto). All the object files on the command line are
588 loaded in memory and processed as a single translation unit.
589 This is the traditional link-time optimization behavior.
591 - WPA (-fwpa). Only the callgraph and summary information for
592 files in the command file are loaded. A single callgraph
593 (without function bodies) is instantiated for the whole set of
594 files. IPA passes are only allowed to analyze the call graph
595 and make transformation decisions. The callgraph is
596 partitioned, each partition is written to a new object file
597 together with the transformation decisions.
599 - LTRANS (-fltrans). Similar to -flto but it prevents the IPA
600 summary files from running again. Since WPA computed summary
601 information and decided what transformations to apply, LTRANS
602 simply applies them. */
607 /* LTO is called as a front end, even though it is not a front end.
608 Because it is called as a front end, TV_PHASE_PARSING and
609 TV_PARSE_GLOBAL are active, and we need to turn them off while
610 doing LTO. Later we turn them back on so they are active up in
612 timevar_pop (TV_PARSE_GLOBAL
);
613 timevar_stop (TV_PHASE_PARSING
);
615 timevar_start (TV_PHASE_SETUP
);
617 /* Initialize the LTO front end. */
620 timevar_stop (TV_PHASE_SETUP
);
621 timevar_start (TV_PHASE_STREAM_IN
);
623 /* Read all the symbols and call graph from all the files in the
625 read_cgraph_and_symbols (num_in_fnames
, in_fnames
);
627 timevar_stop (TV_PHASE_STREAM_IN
);
631 offload_handle_link_vars ();
633 /* If WPA is enabled analyze the whole call graph and create an
634 optimization plan. Otherwise, read in all the function
635 bodies and continue with optimization. */
637 do_whole_program_analysis ();
640 timevar_start (TV_PHASE_OPT_GEN
);
642 materialize_cgraph ();
644 lto_promote_statics_nonwpa ();
646 /* Annotate the CU DIE and mark the early debug phase as finished. */
647 debuginfo_early_start ();
648 debug_hooks
->early_finish ("<artificial>");
649 debuginfo_early_stop ();
651 /* Let the middle end know that we have read and merged all of
655 timevar_stop (TV_PHASE_OPT_GEN
);
657 /* FIXME lto, if the processes spawned by WPA fail, we miss
658 the chance to print WPA's report, so WPA will call
659 print_lto_report before launching LTRANS. If LTRANS was
660 launched directly by the driver we would not need to do
662 if (flag_lto_report
|| (flag_wpa
&& flag_lto_report_wpa
))
663 print_lto_report_1 ();
667 /* Here we make LTO pretend to be a parser. */
668 timevar_start (TV_PHASE_PARSING
);
669 timevar_push (TV_PARSE_GLOBAL
);