1 /* LTO partitioning logic routines.
2 Copyright (C) 2009-2015 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
27 #include "double-int.h"
35 #include "fold-const.h"
38 #include "hard-reg-set.h"
41 #include "basic-block.h"
42 #include "tree-ssa-alias.h"
43 #include "internal-fn.h"
44 #include "gimple-expr.h"
48 #include "plugin-api.h"
51 #include "lto-streamer.h"
54 #include "alloc-pool.h"
55 #include "symbol-summary.h"
57 #include "ipa-inline.h"
58 #include "ipa-utils.h"
59 #include "lto-partition.h"
60 #include "stringpool.h"
62 vec<ltrans_partition> ltrans_partitions;
64 static void add_symbol_to_partition (ltrans_partition part, symtab_node *node);
67 /* Create new partition with name NAME. */
69 static ltrans_partition
70 new_partition (const char *name)
72 ltrans_partition part = XCNEW (struct ltrans_partition_def);
73 part->encoder = lto_symtab_encoder_new (false);
76 ltrans_partitions.safe_push (part);
80 /* Free memory used by ltrans datastructures. */
83 free_ltrans_partitions (void)
86 ltrans_partition part;
87 for (idx = 0; ltrans_partitions.iterate (idx, &part); idx++)
89 if (part->initializers_visited)
90 delete part->initializers_visited;
91 /* Symtab encoder is freed after streaming. */
94 ltrans_partitions.release ();
97 /* Return true if symbol is already in some partition. */
100 symbol_partitioned_p (symtab_node *node)
105 /* Add references into the partition. */
107 add_references_to_partition (ltrans_partition part, symtab_node *node)
110 struct ipa_ref *ref = NULL;
112 /* Add all duplicated references to the partition. */
113 for (i = 0; node->iterate_reference (i, ref); i++)
114 if (ref->referred->get_partitioning_class () == SYMBOL_DUPLICATE)
115 add_symbol_to_partition (part, ref->referred);
116 /* References to a readonly variable may be constant foled into its value.
117 Recursively look into the initializers of the constant variable and add
119 else if (is_a <varpool_node *> (ref->referred)
120 && (dyn_cast <varpool_node *> (ref->referred)
121 ->ctor_useable_for_folding_p ()
122 || POINTER_BOUNDS_P (ref->referred->decl))
123 && !lto_symtab_encoder_in_partition_p (part->encoder, ref->referred))
125 if (!part->initializers_visited)
126 part->initializers_visited = new hash_set<symtab_node *>;
127 if (!part->initializers_visited->add (ref->referred))
128 add_references_to_partition (part, ref->referred);
132 /* Helper function for add_symbol_to_partition doing the actual dirty work
133 of adding NODE to PART. */
136 add_symbol_to_partition_1 (ltrans_partition part, symtab_node *node)
138 enum symbol_partitioning_class c = node->get_partitioning_class ();
142 /* If NODE is already there, we have nothing to do. */
143 if (lto_symtab_encoder_in_partition_p (part->encoder, node))
146 /* non-duplicated aliases or tunks of a duplicated symbol needs to be output
149 Be lax about comdats; they may or may not be duplicated and we may
150 end up in need to duplicate keyed comdat because it has unkeyed alias. */
151 if (c == SYMBOL_PARTITION && !DECL_COMDAT (node->decl)
152 && symbol_partitioned_p (node))
155 /* Be sure that we never try to duplicate partitioned symbol
156 or add external symbol. */
157 gcc_assert (c != SYMBOL_EXTERNAL
158 && (c == SYMBOL_DUPLICATE || !symbol_partitioned_p (node)));
160 lto_set_symtab_encoder_in_partition (part->encoder, node);
162 if (symbol_partitioned_p (node))
164 node->in_other_partition = 1;
165 if (symtab->dump_file)
166 fprintf (symtab->dump_file,
167 "Symbol node %s now used in multiple partitions\n",
170 node->aux = (void *)((size_t)node->aux + 1);
172 if (cgraph_node *cnode = dyn_cast <cgraph_node *> (node))
174 struct cgraph_edge *e;
176 part->insns += inline_summaries->get (cnode)->self_size;
178 /* Add all inline clones and callees that are duplicated. */
179 for (e = cnode->callees; e; e = e->next_callee)
180 if (!e->inline_failed)
181 add_symbol_to_partition_1 (part, e->callee);
182 else if (e->callee->get_partitioning_class () == SYMBOL_DUPLICATE)
183 add_symbol_to_partition (part, e->callee);
185 /* Add all thunks associated with the function. */
186 for (e = cnode->callers; e; e = e->next_caller)
187 if (e->caller->thunk.thunk_p)
188 add_symbol_to_partition_1 (part, e->caller);
190 /* Instrumented version is actually the same function.
191 Therefore put it into the same partition. */
192 if (cnode->instrumented_version)
193 add_symbol_to_partition_1 (part, cnode->instrumented_version);
196 add_references_to_partition (part, node);
198 /* Add all aliases associated with the symbol. */
200 FOR_EACH_ALIAS (node, ref)
202 add_symbol_to_partition_1 (part, ref->referring);
204 /* Ensure that SAME_COMDAT_GROUP lists all allways added in a group. */
205 if (node->same_comdat_group)
206 for (node1 = node->same_comdat_group;
207 node1 != node; node1 = node1->same_comdat_group)
210 bool added = add_symbol_to_partition_1 (part, node1);
216 /* If symbol NODE is really part of other symbol's definition (i.e. it is
217 internal label, thunk, alias or so), return the outer symbol.
218 When add_symbol_to_partition_1 is called on the outer symbol it must
219 eventually add NODE, too. */
221 contained_in_symbol (symtab_node *node)
223 /* Weakrefs are never contained in anything. */
226 if (cgraph_node *cnode = dyn_cast <cgraph_node *> (node))
228 cnode = cnode->function_symbol ();
229 if (cnode->global.inlined_to)
230 cnode = cnode->global.inlined_to;
233 else if (varpool_node *vnode = dyn_cast <varpool_node *> (node))
234 return vnode->ultimate_alias_target ();
238 /* Add symbol NODE to partition. When definition of NODE is part
239 of other symbol definition, add the other symbol, too. */
242 add_symbol_to_partition (ltrans_partition part, symtab_node *node)
246 /* Verify that we do not try to duplicate something that can not be. */
247 gcc_checking_assert (node->get_partitioning_class () == SYMBOL_DUPLICATE
248 || !symbol_partitioned_p (node));
250 while ((node1 = contained_in_symbol (node)) != node)
253 /* If we have duplicated symbol contained in something we can not duplicate,
254 we are very badly screwed. The other way is possible, so we do not
255 assert this in add_symbol_to_partition_1.
257 Be lax about comdats; they may or may not be duplicated and we may
258 end up in need to duplicate keyed comdat because it has unkeyed alias. */
260 gcc_assert (node->get_partitioning_class () == SYMBOL_DUPLICATE
261 || DECL_COMDAT (node->decl)
262 || !symbol_partitioned_p (node));
264 add_symbol_to_partition_1 (part, node);
267 /* Undo all additions until number of cgraph nodes in PARITION is N_CGRAPH_NODES
268 and number of varpool nodes is N_VARPOOL_NODES. */
271 undo_partition (ltrans_partition partition, unsigned int n_nodes)
273 while (lto_symtab_encoder_size (partition->encoder) > (int)n_nodes)
275 symtab_node *node = lto_symtab_encoder_deref (partition->encoder,
279 /* After UNDO we no longer know what was visited. */
280 if (partition->initializers_visited)
281 delete partition->initializers_visited;
282 partition->initializers_visited = NULL;
284 if (!node->alias && (cnode = dyn_cast <cgraph_node *> (node)))
285 partition->insns -= inline_summaries->get (cnode)->self_size;
286 lto_symtab_encoder_delete_node (partition->encoder, node);
287 node->aux = (void *)((size_t)node->aux - 1);
291 /* Group cgrah nodes by input files. This is used mainly for testing
295 lto_1_to_1_map (void)
298 struct lto_file_decl_data *file_data;
299 hash_map<lto_file_decl_data *, ltrans_partition> pmap;
300 ltrans_partition partition;
303 FOR_EACH_SYMBOL (node)
305 if (node->get_partitioning_class () != SYMBOL_PARTITION
306 || symbol_partitioned_p (node))
309 file_data = node->lto_file_data;
313 ltrans_partition *slot = &pmap.get_or_insert (file_data);
318 partition = new_partition (file_data->file_name);
323 else if (!file_data && ltrans_partitions.length ())
324 partition = ltrans_partitions[0];
327 partition = new_partition ("");
328 pmap.put (NULL, partition);
332 add_symbol_to_partition (partition, node);
335 /* If the cgraph is empty, create one cgraph node set so that there is still
336 an output file for any variables that need to be exported in a DSO. */
338 new_partition ("empty");
342 /* Maximal partitioning. Put every new symbol into new partition if possible. */
348 ltrans_partition partition;
351 FOR_EACH_SYMBOL (node)
353 if (node->get_partitioning_class () != SYMBOL_PARTITION
354 || symbol_partitioned_p (node))
356 partition = new_partition (node->asm_name ());
357 add_symbol_to_partition (partition, node);
361 new_partition ("empty");
364 /* Helper function for qsort; sort nodes by order. noreorder functions must have
365 been removed earlier. */
367 node_cmp (const void *pa, const void *pb)
369 const struct cgraph_node *a = *(const struct cgraph_node * const *) pa;
370 const struct cgraph_node *b = *(const struct cgraph_node * const *) pb;
372 /* Profile reorder flag enables function reordering based on first execution
373 of a function. All functions with profile are placed in ascending
374 order at the beginning. */
376 if (flag_profile_reorder_functions)
378 /* Functions with time profile are sorted in ascending order. */
379 if (a->tp_first_run && b->tp_first_run)
380 return a->tp_first_run != b->tp_first_run
381 ? a->tp_first_run - b->tp_first_run
382 : a->order - b->order;
384 /* Functions with time profile are sorted before the functions
385 that do not have the profile. */
386 if (a->tp_first_run || b->tp_first_run)
387 return b->tp_first_run - a->tp_first_run;
390 return b->order - a->order;
393 /* Helper function for qsort; sort nodes by order. */
395 varpool_node_cmp (const void *pa, const void *pb)
397 const symtab_node *a = *static_cast<const symtab_node * const *> (pa);
398 const symtab_node *b = *static_cast<const symtab_node * const *> (pb);
399 return b->order - a->order;
402 /* Add all symtab nodes from NEXT_NODE to PARTITION in order. */
405 add_sorted_nodes (vec<symtab_node *> &next_nodes, ltrans_partition partition)
410 next_nodes.qsort (varpool_node_cmp);
411 FOR_EACH_VEC_ELT (next_nodes, i, node)
412 if (!symbol_partitioned_p (node))
413 add_symbol_to_partition (partition, node);
417 /* Group cgraph nodes into equally-sized partitions.
419 The partitioning algorithm is simple: nodes are taken in predefined order.
420 The order corresponds to the order we want functions to have in the final
421 output. In the future this will be given by function reordering pass, but
422 at the moment we use the topological order, which is a good approximation.
424 The goal is to partition this linear order into intervals (partitions) so
425 that all the partitions have approximately the same size and the number of
426 callgraph or IPA reference edges crossing boundaries is minimal.
428 This is a lot faster (O(n) in size of callgraph) than algorithms doing
429 priority-based graph clustering that are generally O(n^2) and, since
430 WHOPR is designed to make things go well across partitions, it leads
433 We compute the expected size of a partition as:
435 max (total_size / lto_partitions, min_partition_size)
437 We use dynamic expected size of partition so small programs are partitioned
438 into enough partitions to allow use of multiple CPUs, while large programs
439 are not partitioned too much. Creating too many partitions significantly
440 increases the streaming overhead.
442 In the future, we would like to bound the maximal size of partitions so as
443 to prevent the LTRANS stage from consuming too much memory. At the moment,
444 however, the WPA stage is the most memory intensive for large benchmarks,
445 since too many types and declarations are read into memory.
447 The function implements a simple greedy algorithm. Nodes are being added
448 to the current partition until after 3/4 of the expected partition size is
449 reached. Past this threshold, we keep track of boundary size (number of
450 edges going to other partitions) and continue adding functions until after
451 the current partition has grown to twice the expected partition size. Then
452 the process is undone to the point where the minimal ratio of boundary size
453 and in-partition calls was reached. */
456 lto_balanced_map (int n_lto_partitions)
459 int n_varpool_nodes = 0, varpool_pos = 0, best_varpool_pos = 0;
460 struct cgraph_node **order = XNEWVEC (cgraph_node *, symtab->cgraph_max_uid);
461 auto_vec<cgraph_node *> noreorder;
462 auto_vec<varpool_node *> varpool_order;
464 struct cgraph_node *node;
465 int total_size = 0, best_total_size = 0;
467 ltrans_partition partition;
468 int last_visited_node = 0;
470 int cost = 0, internal = 0;
471 int best_n_nodes = 0, best_i = 0, best_cost =
472 INT_MAX, best_internal = 0;
474 int current_order = -1;
475 int noreorder_pos = 0;
477 FOR_EACH_VARIABLE (vnode)
478 gcc_assert (!vnode->aux);
480 FOR_EACH_DEFINED_FUNCTION (node)
481 if (node->get_partitioning_class () == SYMBOL_PARTITION)
483 if (node->no_reorder)
484 noreorder.safe_push (node);
486 order[n_nodes++] = node;
488 total_size += inline_summaries->get (node)->size;
491 /* Streaming works best when the source units do not cross partition
492 boundaries much. This is because importing function from a source
493 unit tends to import a lot of global trees defined there. We should
494 get better about minimizing the function bounday, but until that
495 things works smoother if we order in source order. */
496 qsort (order, n_nodes, sizeof (struct cgraph_node *), node_cmp);
497 noreorder.qsort (node_cmp);
499 if (symtab->dump_file)
501 for(i = 0; i < n_nodes; i++)
502 fprintf (symtab->dump_file, "Balanced map symbol order:%s:%u\n",
503 order[i]->name (), order[i]->tp_first_run);
504 for(i = 0; i < (int)noreorder.length(); i++)
505 fprintf (symtab->dump_file, "Balanced map symbol no_reorder:%s:%u\n",
506 noreorder[i]->name (), noreorder[i]->tp_first_run);
509 /* Collect all variables that should not be reordered. */
510 FOR_EACH_VARIABLE (vnode)
511 if (vnode->get_partitioning_class () == SYMBOL_PARTITION
512 && (!flag_toplevel_reorder || vnode->no_reorder))
513 varpool_order.safe_push (vnode);
514 n_varpool_nodes = varpool_order.length ();
515 varpool_order.qsort (varpool_node_cmp);
517 /* Compute partition size and create the first partition. */
518 partition_size = total_size / n_lto_partitions;
519 if (partition_size < PARAM_VALUE (MIN_PARTITION_SIZE))
520 partition_size = PARAM_VALUE (MIN_PARTITION_SIZE);
522 partition = new_partition ("");
523 if (symtab->dump_file)
524 fprintf (symtab->dump_file, "Total unit size: %i, partition size: %i\n",
525 total_size, partition_size);
527 auto_vec<symtab_node *> next_nodes;
529 for (i = 0; i < n_nodes; i++)
531 if (symbol_partitioned_p (order[i]))
534 current_order = order[i]->order;
536 /* Output noreorder and varpool in program order first. */
537 next_nodes.truncate (0);
538 while (varpool_pos < n_varpool_nodes
539 && varpool_order[varpool_pos]->order < current_order)
540 next_nodes.safe_push (varpool_order[varpool_pos++]);
541 while (noreorder_pos < (int)noreorder.length ()
542 && noreorder[noreorder_pos]->order < current_order)
544 if (!noreorder[noreorder_pos]->alias)
545 total_size -= inline_summaries->get (noreorder[noreorder_pos])->size;
546 next_nodes.safe_push (noreorder[noreorder_pos++]);
548 add_sorted_nodes (next_nodes, partition);
550 add_symbol_to_partition (partition, order[i]);
551 if (!order[i]->alias)
552 total_size -= inline_summaries->get (order[i])->size;
555 /* Once we added a new node to the partition, we also want to add
556 all referenced variables unless they was already added into some
558 add_symbol_to_partition adds possibly multiple nodes and
559 variables that are needed to satisfy needs of ORDER[i].
560 We remember last visited cgraph and varpool node from last iteration
561 of outer loop that allows us to process every new addition.
563 At the same time we compute size of the boundary into COST. Every
564 callgraph or IPA reference edge leaving the partition contributes into
565 COST. Every edge inside partition was earlier computed as one leaving
566 it and thus we need to subtract it from COST. */
567 while (last_visited_node < lto_symtab_encoder_size (partition->encoder))
569 symtab_node *refs_node;
571 struct ipa_ref *ref = NULL;
572 symtab_node *snode = lto_symtab_encoder_deref (partition->encoder,
575 if (cgraph_node *node = dyn_cast <cgraph_node *> (snode))
577 struct cgraph_edge *edge;
583 gcc_assert (node->definition || node->weakref);
585 /* Compute boundary cost of callgraph edges. */
586 for (edge = node->callees; edge; edge = edge->next_callee)
587 if (edge->callee->definition)
589 int edge_cost = edge->frequency;
594 gcc_assert (edge_cost > 0);
595 index = lto_symtab_encoder_lookup (partition->encoder,
597 if (index != LCC_NOT_FOUND
598 && index < last_visited_node - 1)
599 cost -= edge_cost, internal += edge_cost;
603 for (edge = node->callers; edge; edge = edge->next_caller)
605 int edge_cost = edge->frequency;
608 gcc_assert (edge->caller->definition);
611 gcc_assert (edge_cost > 0);
612 index = lto_symtab_encoder_lookup (partition->encoder,
614 if (index != LCC_NOT_FOUND
615 && index < last_visited_node - 1)
627 /* Compute boundary cost of IPA REF edges and at the same time look into
628 variables referenced from current partition and try to add them. */
629 for (j = 0; refs_node->iterate_reference (j, ref); j++)
630 if (is_a <varpool_node *> (ref->referred))
634 vnode = dyn_cast <varpool_node *> (ref->referred);
635 if (!vnode->definition)
637 if (!symbol_partitioned_p (vnode) && flag_toplevel_reorder
638 && !vnode->no_reorder
639 && vnode->get_partitioning_class () == SYMBOL_PARTITION)
640 add_symbol_to_partition (partition, vnode);
641 index = lto_symtab_encoder_lookup (partition->encoder,
643 if (index != LCC_NOT_FOUND
644 && index < last_visited_node - 1)
653 node = dyn_cast <cgraph_node *> (ref->referred);
654 if (!node->definition)
656 index = lto_symtab_encoder_lookup (partition->encoder,
658 if (index != LCC_NOT_FOUND
659 && index < last_visited_node - 1)
664 for (j = 0; refs_node->iterate_referring (j, ref); j++)
665 if (is_a <varpool_node *> (ref->referring))
669 vnode = dyn_cast <varpool_node *> (ref->referring);
670 gcc_assert (vnode->definition);
671 /* It is better to couple variables with their users, because it allows them
672 to be removed. Coupling with objects they refer to only helps to reduce
673 number of symbols promoted to hidden. */
674 if (!symbol_partitioned_p (vnode) && flag_toplevel_reorder
675 && !vnode->no_reorder
676 && !vnode->can_remove_if_no_refs_p ()
677 && vnode->get_partitioning_class () == SYMBOL_PARTITION)
678 add_symbol_to_partition (partition, vnode);
679 index = lto_symtab_encoder_lookup (partition->encoder,
681 if (index != LCC_NOT_FOUND
682 && index < last_visited_node - 1)
691 node = dyn_cast <cgraph_node *> (ref->referring);
692 gcc_assert (node->definition);
693 index = lto_symtab_encoder_lookup (partition->encoder,
695 if (index != LCC_NOT_FOUND
696 && index < last_visited_node - 1)
703 /* If the partition is large enough, start looking for smallest boundary cost. */
704 if (partition->insns < partition_size * 3 / 4
705 || best_cost == INT_MAX
707 || (best_internal * (HOST_WIDE_INT) cost
708 > (internal * (HOST_WIDE_INT)best_cost)))
709 && partition->insns < partition_size * 5 / 4))
712 best_internal = internal;
714 best_n_nodes = lto_symtab_encoder_size (partition->encoder);
715 best_total_size = total_size;
716 best_varpool_pos = varpool_pos;
718 if (symtab->dump_file)
719 fprintf (symtab->dump_file, "Step %i: added %s/%i, size %i, cost %i/%i "
720 "best %i/%i, step %i\n", i,
721 order[i]->name (), order[i]->order,
722 partition->insns, cost, internal,
723 best_cost, best_internal, best_i);
724 /* Partition is too large, unwind into step when best cost was reached and
725 start new partition. */
726 if (partition->insns > 2 * partition_size)
730 if (symtab->dump_file)
731 fprintf (symtab->dump_file, "Unwinding %i insertions to step %i\n",
733 undo_partition (partition, best_n_nodes);
734 varpool_pos = best_varpool_pos;
737 /* When we are finished, avoid creating empty partition. */
738 while (i < n_nodes - 1 && symbol_partitioned_p (order[i + 1]))
740 if (i == n_nodes - 1)
742 partition = new_partition ("");
743 last_visited_node = 0;
744 total_size = best_total_size;
747 if (symtab->dump_file)
748 fprintf (symtab->dump_file, "New partition\n");
752 /* Since the size of partitions is just approximate, update the size after
753 we finished current one. */
754 if (npartitions < n_lto_partitions)
755 partition_size = total_size / (n_lto_partitions - npartitions);
757 partition_size = INT_MAX;
759 if (partition_size < PARAM_VALUE (MIN_PARTITION_SIZE))
760 partition_size = PARAM_VALUE (MIN_PARTITION_SIZE);
765 next_nodes.truncate (0);
767 /* Varables that are not reachable from the code go into last partition. */
768 if (flag_toplevel_reorder)
770 FOR_EACH_VARIABLE (vnode)
771 if (vnode->get_partitioning_class () == SYMBOL_PARTITION
772 && !symbol_partitioned_p (vnode)
773 && !vnode->no_reorder)
774 next_nodes.safe_push (vnode);
777 /* Output remaining ordered symbols. */
778 while (varpool_pos < n_varpool_nodes)
779 next_nodes.safe_push (varpool_order[varpool_pos++]);
780 while (noreorder_pos < (int)noreorder.length ())
781 next_nodes.safe_push (noreorder[noreorder_pos++]);
782 add_sorted_nodes (next_nodes, partition);
787 /* Return true if we must not change the name of the NODE. The name as
788 extracted from the corresponding decl should be passed in NAME. */
791 must_not_rename (symtab_node *node, const char *name)
793 /* Our renaming machinery do not handle more than one change of assembler name.
794 We should not need more than one anyway. */
795 if (node->lto_file_data
796 && lto_get_decl_name_mapping (node->lto_file_data, name) != name)
798 if (symtab->dump_file)
799 fprintf (symtab->dump_file,
800 "Not privatizing symbol name: %s. It privatized already.\n",
804 /* Avoid mangling of already mangled clones.
805 ??? should have a flag whether a symbol has a 'private' name already,
806 since we produce some symbols like that i.e. for global constructors
807 that are not really clones. */
808 if (node->unique_name)
810 if (symtab->dump_file)
811 fprintf (symtab->dump_file,
812 "Not privatizing symbol name: %s. Has unique name.\n",
819 /* If we are an offload compiler, we may have to rewrite symbols to be
820 valid on this target. Return either PTR or a modified version of it. */
823 maybe_rewrite_identifier (const char *ptr)
825 #if defined ACCEL_COMPILER && (defined NO_DOT_IN_LABEL || defined NO_DOLLAR_IN_LABEL)
826 #ifndef NO_DOT_IN_LABEL
828 const char reject[] = "$";
829 #elif !defined NO_DOLLAR_IN_LABEL
831 const char reject[] = ".";
834 const char reject[] = ".$";
838 const char *match = ptr;
841 size_t off = strcspn (match, reject);
842 if (match[off] == '\0')
846 copy = xstrdup (ptr);
857 /* Ensure that the symbol in NODE is valid for the target, and if not,
861 validize_symbol_for_target (symtab_node *node)
863 tree decl = node->decl;
864 const char *name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
866 if (must_not_rename (node, name))
869 const char *name2 = maybe_rewrite_identifier (name);
872 symtab->change_decl_assembler_name (decl, get_identifier (name2));
873 if (node->lto_file_data)
874 lto_record_renamed_decl (node->lto_file_data, name,
876 (DECL_ASSEMBLER_NAME (decl)));
880 /* Mangle NODE symbol name into a local name.
881 This is necessary to do
882 1) if two or more static vars of same assembler name
883 are merged into single ltrans unit.
884 2) if previously static var was promoted hidden to avoid possible conflict
885 with symbols defined out of the LTO world. */
888 privatize_symbol_name (symtab_node *node)
890 tree decl = node->decl;
892 cgraph_node *cnode = dyn_cast <cgraph_node *> (node);
894 /* If we want to privatize instrumentation clone
895 then we need to change original function name
896 which is used via transparent alias chain. */
897 if (cnode && cnode->instrumentation_clone)
898 decl = cnode->orig_decl;
900 name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
902 if (must_not_rename (node, name))
905 name = maybe_rewrite_identifier (name);
906 symtab->change_decl_assembler_name (decl,
907 clone_function_name_1 (name,
909 if (node->lto_file_data)
910 lto_record_renamed_decl (node->lto_file_data, name,
912 (DECL_ASSEMBLER_NAME (decl)));
913 /* We could change name which is a target of transparent alias
914 chain of instrumented function name. Fix alias chain if so .*/
917 tree iname = NULL_TREE;
918 if (cnode->instrumentation_clone)
919 iname = DECL_ASSEMBLER_NAME (cnode->decl);
920 else if (cnode->instrumented_version
921 && cnode->instrumented_version->orig_decl == decl)
922 iname = DECL_ASSEMBLER_NAME (cnode->instrumented_version->decl);
926 gcc_assert (IDENTIFIER_TRANSPARENT_ALIAS (iname));
927 TREE_CHAIN (iname) = DECL_ASSEMBLER_NAME (decl);
930 if (symtab->dump_file)
931 fprintf (symtab->dump_file,
932 "Privatizing symbol name: %s -> %s\n",
933 name, IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)));
937 /* Promote variable VNODE to be static. */
940 promote_symbol (symtab_node *node)
942 /* We already promoted ... */
943 if (DECL_VISIBILITY (node->decl) == VISIBILITY_HIDDEN
944 && DECL_VISIBILITY_SPECIFIED (node->decl)
945 && TREE_PUBLIC (node->decl))
947 validize_symbol_for_target (node);
951 gcc_checking_assert (!TREE_PUBLIC (node->decl)
952 && !DECL_EXTERNAL (node->decl));
953 /* Be sure that newly public symbol does not conflict with anything already
954 defined by the non-LTO part. */
955 privatize_symbol_name (node);
956 TREE_PUBLIC (node->decl) = 1;
957 DECL_VISIBILITY (node->decl) = VISIBILITY_HIDDEN;
958 DECL_VISIBILITY_SPECIFIED (node->decl) = true;
959 if (symtab->dump_file)
960 fprintf (symtab->dump_file,
961 "Promoting as hidden: %s\n", node->name ());
964 /* Return true if NODE needs named section even if it won't land in the partition
966 FIXME: we should really not use named sections for inline clones and master clones. */
969 may_need_named_section_p (lto_symtab_encoder_t encoder, symtab_node *node)
971 struct cgraph_node *cnode = dyn_cast <cgraph_node *> (node);
974 if (node->real_symbol_p ())
977 || (lto_symtab_encoder_lookup (encoder, node) != LCC_NOT_FOUND
978 && lto_symtab_encoder_encode_body_p (encoder,
982 /* If NODE represents a static variable. See if there are other variables
983 of the same name in partition ENCODER (or in whole compilation unit if
984 ENCODER is NULL) and if so, mangle the statics. Always mangle all
985 conflicting statics, so we reduce changes of silently miscompiling
986 asm statements referring to them by symbol name. */
989 rename_statics (lto_symtab_encoder_t encoder, symtab_node *node)
991 tree decl = node->decl;
993 tree name = DECL_ASSEMBLER_NAME (decl);
995 /* See if this is static symbol. */
996 if ((node->externally_visible
997 /* FIXME: externally_visible is somewhat illogically not set for
998 external symbols (i.e. those not defined). Remove this test
999 once this is fixed. */
1000 || DECL_EXTERNAL (node->decl)
1001 || !node->real_symbol_p ())
1002 && !may_need_named_section_p (encoder, node))
1005 /* Now walk symbols sharing the same name and see if there are any conflicts.
1006 (all types of symbols counts here, since we can not have static of the
1007 same name as external or public symbol.) */
1008 for (s = symtab_node::get_for_asmname (name);
1009 s; s = s->next_sharing_asm_name)
1010 if ((s->real_symbol_p () || may_need_named_section_p (encoder, s))
1011 && s->decl != node->decl
1013 || lto_symtab_encoder_lookup (encoder, s) != LCC_NOT_FOUND))
1016 /* OK, no confict, so we have nothing to do. */
1020 if (symtab->dump_file)
1021 fprintf (symtab->dump_file,
1022 "Renaming statics with asm name: %s\n", node->name ());
1024 /* Assign every symbol in the set that shares the same ASM name an unique
1026 for (s = symtab_node::get_for_asmname (name); s;)
1027 if (!s->externally_visible
1028 && ((s->real_symbol_p ()
1029 && !DECL_EXTERNAL (node->decl)
1030 && !TREE_PUBLIC (node->decl))
1031 || may_need_named_section_p (encoder, s))
1033 || lto_symtab_encoder_lookup (encoder, s) != LCC_NOT_FOUND))
1035 if (privatize_symbol_name (s))
1036 /* Re-start from beginning since we do not know how many symbols changed a name. */
1037 s = symtab_node::get_for_asmname (name);
1038 else s = s->next_sharing_asm_name;
1040 else s = s->next_sharing_asm_name;
1043 /* Find out all static decls that need to be promoted to global because
1044 of cross file sharing. This function must be run in the WPA mode after
1045 all inlinees are added. */
1048 lto_promote_cross_file_statics (void)
1052 gcc_assert (flag_wpa);
1054 lto_stream_offload_p = false;
1055 select_what_to_stream ();
1057 /* First compute boundaries. */
1058 n_sets = ltrans_partitions.length ();
1059 for (i = 0; i < n_sets; i++)
1061 ltrans_partition part
1062 = ltrans_partitions[i];
1063 part->encoder = compute_ltrans_boundary (part->encoder);
1066 /* Look at boundaries and promote symbols as needed. */
1067 for (i = 0; i < n_sets; i++)
1069 lto_symtab_encoder_iterator lsei;
1070 lto_symtab_encoder_t encoder = ltrans_partitions[i]->encoder;
1072 for (lsei = lsei_start (encoder); !lsei_end_p (lsei);
1075 symtab_node *node = lsei_node (lsei);
1077 /* If symbol is static, rename it if its assembler name clash with
1078 anything else in this unit. */
1079 rename_statics (encoder, node);
1081 /* No need to promote if symbol already is externally visible ... */
1082 if (node->externally_visible
1083 /* ... or if it is part of current partition ... */
1084 || lto_symtab_encoder_in_partition_p (encoder, node)
1085 /* ... or if we do not partition it. This mean that it will
1086 appear in every partition refernecing it. */
1087 || node->get_partitioning_class () != SYMBOL_PARTITION)
1089 validize_symbol_for_target (node);
1093 promote_symbol (node);
1098 /* Rename statics in the whole unit in the case that
1099 we do -flto-partition=none. */
1102 lto_promote_statics_nonwpa (void)
1105 FOR_EACH_SYMBOL (node)
1107 rename_statics (NULL, node);
1108 validize_symbol_for_target (node);