2 Copyright 2009, 2010 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"
24 #include "diagnostic-core.h"
29 #include "plugin-api.h"
30 #include "lto-streamer.h"
32 /* Vector to keep track of external variables we've seen so far. */
33 VEC(tree
,gc
) *lto_global_var_decls
;
35 /* Symbol table entry. */
37 struct GTY(()) lto_symtab_entry_def
39 /* The symbol table entry key, an IDENTIFIER. */
41 /* The symbol table entry, a DECL. */
43 /* The cgraph node if decl is a function decl. Filled in during the
45 struct cgraph_node
*node
;
46 /* The varpool node if decl is a variable decl. Filled in during the
48 struct varpool_node
*vnode
;
49 /* LTO file-data and symbol resolution for this decl. */
50 struct lto_file_decl_data
* GTY((skip (""))) file_data
;
51 enum ld_plugin_symbol_resolution resolution
;
52 /* True when resolution was guessed and not read from the file. */
54 /* Pointer to the next entry with the same key. Before decl merging
55 this links all symbols from the different TUs. After decl merging
56 this links merged but incompatible decls, thus all prevailing ones
58 struct lto_symtab_entry_def
*next
;
60 typedef struct lto_symtab_entry_def
*lto_symtab_entry_t
;
62 /* A poor man's symbol table. This hashes identifier to prevailing DECL
65 static GTY ((if_marked ("lto_symtab_entry_marked_p"),
66 param_is (struct lto_symtab_entry_def
)))
67 htab_t lto_symtab_identifiers
;
69 /* Free symtab hashtable. */
72 lto_symtab_free (void)
74 htab_delete (lto_symtab_identifiers
);
75 lto_symtab_identifiers
= NULL
;
78 /* Return the hash value of an lto_symtab_entry_t object pointed to by P. */
81 lto_symtab_entry_hash (const void *p
)
83 const struct lto_symtab_entry_def
*base
=
84 (const struct lto_symtab_entry_def
*) p
;
85 return IDENTIFIER_HASH_VALUE (base
->id
);
88 /* Return non-zero if P1 and P2 points to lto_symtab_entry_def structs
89 corresponding to the same symbol. */
92 lto_symtab_entry_eq (const void *p1
, const void *p2
)
94 const struct lto_symtab_entry_def
*base1
=
95 (const struct lto_symtab_entry_def
*) p1
;
96 const struct lto_symtab_entry_def
*base2
=
97 (const struct lto_symtab_entry_def
*) p2
;
98 return (base1
->id
== base2
->id
);
101 /* Returns non-zero if P points to an lto_symtab_entry_def struct that needs
102 to be marked for GC. */
105 lto_symtab_entry_marked_p (const void *p
)
107 const struct lto_symtab_entry_def
*base
=
108 (const struct lto_symtab_entry_def
*) p
;
110 /* Keep this only if the common IDENTIFIER_NODE of the symtab chain
111 is marked which it will be if at least one of the DECLs in the
113 return ggc_marked_p (base
->id
);
116 /* Lazily initialize resolution hash tables. */
119 lto_symtab_maybe_init_hash_table (void)
121 if (lto_symtab_identifiers
)
124 lto_symtab_identifiers
=
125 htab_create_ggc (1021, lto_symtab_entry_hash
,
126 lto_symtab_entry_eq
, NULL
);
129 /* Registers DECL with the LTO symbol table as having resolution RESOLUTION
130 and read from FILE_DATA. */
133 lto_symtab_register_decl (tree decl
,
134 ld_plugin_symbol_resolution_t resolution
,
135 struct lto_file_decl_data
*file_data
)
137 lto_symtab_entry_t new_entry
;
140 /* Check that declarations reaching this function do not have
141 properties inconsistent with having external linkage. If any of
142 these asertions fail, then the object file reader has failed to
143 detect these cases and issue appropriate error messages. */
145 && TREE_PUBLIC (decl
)
146 && (TREE_CODE (decl
) == VAR_DECL
147 || TREE_CODE (decl
) == FUNCTION_DECL
)
148 && DECL_ASSEMBLER_NAME_SET_P (decl
));
149 if (TREE_CODE (decl
) == VAR_DECL
150 && DECL_INITIAL (decl
))
151 gcc_assert (!DECL_EXTERNAL (decl
)
152 || (TREE_STATIC (decl
) && TREE_READONLY (decl
)));
153 if (TREE_CODE (decl
) == FUNCTION_DECL
)
154 gcc_assert (!DECL_ABSTRACT (decl
));
156 new_entry
= ggc_alloc_cleared_lto_symtab_entry_def ();
157 new_entry
->id
= (*targetm
.asm_out
.mangle_assembler_name
)
158 (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl
)));
159 new_entry
->decl
= decl
;
160 new_entry
->resolution
= resolution
;
161 new_entry
->file_data
= file_data
;
163 lto_symtab_maybe_init_hash_table ();
164 slot
= htab_find_slot (lto_symtab_identifiers
, new_entry
, INSERT
);
165 new_entry
->next
= (lto_symtab_entry_t
) *slot
;
169 /* Get the lto_symtab_entry_def struct associated with ID
172 static lto_symtab_entry_t
173 lto_symtab_get (tree id
)
175 struct lto_symtab_entry_def temp
;
178 lto_symtab_maybe_init_hash_table ();
180 slot
= htab_find_slot (lto_symtab_identifiers
, &temp
, NO_INSERT
);
181 return slot
? (lto_symtab_entry_t
) *slot
: NULL
;
184 /* Get the linker resolution for DECL. */
186 enum ld_plugin_symbol_resolution
187 lto_symtab_get_resolution (tree decl
)
189 lto_symtab_entry_t e
;
191 gcc_assert (DECL_ASSEMBLER_NAME_SET_P (decl
));
193 e
= lto_symtab_get ((*targetm
.asm_out
.mangle_assembler_name
)
194 (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl
))));
195 while (e
&& e
->decl
!= decl
)
200 return e
->resolution
;
204 /* Replace the cgraph node NODE with PREVAILING_NODE in the cgraph, merging
205 all edges and removing the old node. */
208 lto_cgraph_replace_node (struct cgraph_node
*node
,
209 struct cgraph_node
*prevailing_node
)
211 struct cgraph_edge
*e
, *next
;
214 if (cgraph_dump_file
)
216 fprintf (cgraph_dump_file
, "Replacing cgraph node %s/%i by %s/%i"
218 xstrdup (cgraph_node_name (node
)), node
->uid
,
219 xstrdup (cgraph_node_name (prevailing_node
)),
220 prevailing_node
->uid
,
221 IDENTIFIER_POINTER ((*targetm
.asm_out
.mangle_assembler_name
)
222 (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node
->symbol
.decl
)))));
225 /* Merge node flags. */
226 if (node
->symbol
.force_output
)
227 cgraph_mark_force_output_node (prevailing_node
);
228 if (node
->symbol
.address_taken
)
230 gcc_assert (!prevailing_node
->global
.inlined_to
);
231 cgraph_mark_address_taken_node (prevailing_node
);
234 /* Redirect all incoming edges. */
236 = types_compatible_p (TREE_TYPE (TREE_TYPE (prevailing_node
->symbol
.decl
)),
237 TREE_TYPE (TREE_TYPE (node
->symbol
.decl
)));
238 for (e
= node
->callers
; e
; e
= next
)
240 next
= e
->next_caller
;
241 cgraph_redirect_edge_callee (e
, prevailing_node
);
242 /* If there is a mismatch between the supposed callee return type and
243 the real one do not attempt to inline this function.
244 ??? We really need a way to match function signatures for ABI
245 compatibility and perform related promotions at inlining time. */
247 e
->call_stmt_cannot_inline_p
= 1;
249 /* Redirect incomming references. */
250 ipa_clone_referring ((symtab_node
)prevailing_node
, &node
->symbol
.ref_list
);
252 /* Finally remove the replaced node. */
253 cgraph_remove_node (node
);
256 /* Replace the cgraph node NODE with PREVAILING_NODE in the cgraph, merging
257 all edges and removing the old node. */
260 lto_varpool_replace_node (struct varpool_node
*vnode
,
261 struct varpool_node
*prevailing_node
)
263 gcc_assert (!vnode
->finalized
|| prevailing_node
->finalized
);
264 gcc_assert (!vnode
->analyzed
|| prevailing_node
->analyzed
);
266 ipa_clone_referring ((symtab_node
)prevailing_node
, &vnode
->symbol
.ref_list
);
268 /* Be sure we can garbage collect the initializer. */
269 if (DECL_INITIAL (vnode
->symbol
.decl
))
270 DECL_INITIAL (vnode
->symbol
.decl
) = error_mark_node
;
271 /* Finally remove the replaced node. */
272 varpool_remove_node (vnode
);
275 /* Merge two variable or function symbol table entries PREVAILING and ENTRY.
276 Return false if the symbols are not fully compatible and a diagnostic
277 should be emitted. */
280 lto_symtab_merge (lto_symtab_entry_t prevailing
, lto_symtab_entry_t entry
)
282 tree prevailing_decl
= prevailing
->decl
;
283 tree decl
= entry
->decl
;
284 tree prevailing_type
, type
;
286 /* Merge decl state in both directions, we may still end up using
288 TREE_ADDRESSABLE (prevailing_decl
) |= TREE_ADDRESSABLE (decl
);
289 TREE_ADDRESSABLE (decl
) |= TREE_ADDRESSABLE (prevailing_decl
);
291 /* The linker may ask us to combine two incompatible symbols.
292 Detect this case and notify the caller of required diagnostics. */
294 if (TREE_CODE (decl
) == FUNCTION_DECL
)
296 if (!types_compatible_p (TREE_TYPE (prevailing_decl
),
298 /* If we don't have a merged type yet...sigh. The linker
299 wouldn't complain if the types were mismatched, so we
300 probably shouldn't either. Just use the type from
301 whichever decl appears to be associated with the
302 definition. If for some odd reason neither decl is, the
309 /* Now we exclusively deal with VAR_DECLs. */
311 /* Sharing a global symbol is a strong hint that two types are
312 compatible. We could use this information to complete
313 incomplete pointed-to types more aggressively here, ignoring
314 mismatches in both field and tag names. It's difficult though
315 to guarantee that this does not have side-effects on merging
316 more compatible types from other translation units though. */
318 /* We can tolerate differences in type qualification, the
319 qualification of the prevailing definition will prevail.
320 ??? In principle we might want to only warn for structurally
321 incompatible types here, but unless we have protective measures
322 for TBAA in place that would hide useful information. */
323 prevailing_type
= TYPE_MAIN_VARIANT (TREE_TYPE (prevailing_decl
));
324 type
= TYPE_MAIN_VARIANT (TREE_TYPE (decl
));
326 if (!types_compatible_p (prevailing_type
, type
))
328 if (COMPLETE_TYPE_P (type
))
331 /* If type is incomplete then avoid warnings in the cases
332 that TBAA handles just fine. */
334 if (TREE_CODE (prevailing_type
) != TREE_CODE (type
))
337 if (TREE_CODE (prevailing_type
) == ARRAY_TYPE
)
339 tree tem1
= TREE_TYPE (prevailing_type
);
340 tree tem2
= TREE_TYPE (type
);
341 while (TREE_CODE (tem1
) == ARRAY_TYPE
342 && TREE_CODE (tem2
) == ARRAY_TYPE
)
344 tem1
= TREE_TYPE (tem1
);
345 tem2
= TREE_TYPE (tem2
);
348 if (TREE_CODE (tem1
) != TREE_CODE (tem2
))
351 if (!types_compatible_p (tem1
, tem2
))
355 /* Fallthru. Compatible enough. */
358 /* ??? We might want to emit a warning here if type qualification
359 differences were spotted. Do not do this unconditionally though. */
361 /* There is no point in comparing too many details of the decls here.
362 The type compatibility checks or the completing of types has properly
363 dealt with most issues. */
365 /* The following should all not invoke fatal errors as in non-LTO
366 mode the linker wouldn't complain either. Just emit warnings. */
368 /* Report a warning if user-specified alignments do not match. */
369 if ((DECL_USER_ALIGN (prevailing_decl
) && DECL_USER_ALIGN (decl
))
370 && DECL_ALIGN (prevailing_decl
) < DECL_ALIGN (decl
))
376 /* Return true if the symtab entry E can be replaced by another symtab
380 lto_symtab_resolve_replaceable_p (lto_symtab_entry_t e
)
382 if (DECL_EXTERNAL (e
->decl
)
383 || DECL_COMDAT (e
->decl
)
384 || DECL_ONE_ONLY (e
->decl
)
385 || DECL_WEAK (e
->decl
))
388 if (TREE_CODE (e
->decl
) == VAR_DECL
)
389 return (DECL_COMMON (e
->decl
)
390 || (!flag_no_common
&& !DECL_INITIAL (e
->decl
)));
395 /* Return true if the symtab entry E can be the prevailing one. */
398 lto_symtab_resolve_can_prevail_p (lto_symtab_entry_t e
)
400 /* The C++ frontend ends up neither setting TREE_STATIC nor
401 DECL_EXTERNAL on virtual methods but only TREE_PUBLIC.
402 So do not reject !TREE_STATIC here but only DECL_EXTERNAL. */
403 if (DECL_EXTERNAL (e
->decl
))
406 /* For functions we need a non-discarded body. */
407 if (TREE_CODE (e
->decl
) == FUNCTION_DECL
)
408 return (e
->node
&& e
->node
->analyzed
);
410 else if (TREE_CODE (e
->decl
) == VAR_DECL
)
414 return e
->vnode
->finalized
;
420 /* Resolve the symbol with the candidates in the chain *SLOT and store
421 their resolutions. */
424 lto_symtab_resolve_symbols (void **slot
)
426 lto_symtab_entry_t e
;
427 lto_symtab_entry_t prevailing
= NULL
;
429 /* Always set e->node so that edges are updated to reflect decl merging. */
430 for (e
= (lto_symtab_entry_t
) *slot
; e
; e
= e
->next
)
432 if (TREE_CODE (e
->decl
) == FUNCTION_DECL
)
433 e
->node
= cgraph_get_node (e
->decl
);
434 else if (TREE_CODE (e
->decl
) == VAR_DECL
)
435 e
->vnode
= varpool_get_node (e
->decl
);
436 if (e
->resolution
== LDPR_PREVAILING_DEF_IRONLY
437 || e
->resolution
== LDPR_PREVAILING_DEF_IRONLY_EXP
438 || e
->resolution
== LDPR_PREVAILING_DEF
)
442 /* If the chain is already resolved there is nothing else to do. */
446 /* Find the single non-replaceable prevailing symbol and
447 diagnose ODR violations. */
448 for (e
= (lto_symtab_entry_t
) *slot
; e
; e
= e
->next
)
450 if (!lto_symtab_resolve_can_prevail_p (e
))
452 e
->resolution
= LDPR_RESOLVED_IR
;
457 /* Set a default resolution - the final prevailing one will get
459 e
->resolution
= LDPR_PREEMPTED_IR
;
461 if (!lto_symtab_resolve_replaceable_p (e
))
465 error_at (DECL_SOURCE_LOCATION (e
->decl
),
466 "%qD has already been defined", e
->decl
);
467 inform (DECL_SOURCE_LOCATION (prevailing
->decl
),
468 "previously defined here");
476 /* Do a second round choosing one from the replaceable prevailing decls. */
477 for (e
= (lto_symtab_entry_t
) *slot
; e
; e
= e
->next
)
479 if (e
->resolution
!= LDPR_PREEMPTED_IR
)
482 /* Choose the first function that can prevail as prevailing. */
483 if (TREE_CODE (e
->decl
) == FUNCTION_DECL
)
489 /* From variables that can prevail choose the largest one. */
491 || tree_int_cst_lt (DECL_SIZE (prevailing
->decl
),
492 DECL_SIZE (e
->decl
)))
500 /* If current lto files represent the whole program,
501 it is correct to use LDPR_PREVALING_DEF_IRONLY.
502 If current lto files are part of whole program, internal
503 resolver doesn't know if it is LDPR_PREVAILING_DEF
504 or LDPR_PREVAILING_DEF_IRONLY. Use IRONLY conforms to
505 using -fwhole-program. Otherwise, it doesn't
506 matter using either LDPR_PREVAILING_DEF or
507 LDPR_PREVAILING_DEF_IRONLY
509 FIXME: above workaround due to gold plugin makes some
510 variables IRONLY, which are indeed PREVAILING_DEF in
511 resolution file. These variables still need manual
512 externally_visible attribute. */
513 prevailing
->resolution
= LDPR_PREVAILING_DEF_IRONLY
;
514 prevailing
->guessed
= true;
517 /* Merge all decls in the symbol table chain to the prevailing decl and
518 issue diagnostics about type mismatches. If DIAGNOSED_P is true
519 do not issue further diagnostics.*/
522 lto_symtab_merge_decls_2 (void **slot
, bool diagnosed_p
)
524 lto_symtab_entry_t prevailing
, e
;
525 VEC(tree
, heap
) *mismatches
= NULL
;
529 /* Nothing to do for a single entry. */
530 prevailing
= (lto_symtab_entry_t
) *slot
;
531 if (!prevailing
->next
)
534 /* Try to merge each entry with the prevailing one. */
535 for (e
= prevailing
->next
; e
; e
= e
->next
)
537 if (!lto_symtab_merge (prevailing
, e
)
539 VEC_safe_push (tree
, heap
, mismatches
, e
->decl
);
541 if (VEC_empty (tree
, mismatches
))
544 /* Diagnose all mismatched re-declarations. */
545 FOR_EACH_VEC_ELT (tree
, mismatches
, i
, decl
)
547 if (!types_compatible_p (TREE_TYPE (prevailing
->decl
), TREE_TYPE (decl
)))
548 diagnosed_p
|= warning_at (DECL_SOURCE_LOCATION (decl
), 0,
549 "type of %qD does not match original "
550 "declaration", decl
);
552 else if ((DECL_USER_ALIGN (prevailing
->decl
) && DECL_USER_ALIGN (decl
))
553 && DECL_ALIGN (prevailing
->decl
) < DECL_ALIGN (decl
))
555 diagnosed_p
|= warning_at (DECL_SOURCE_LOCATION (decl
), 0,
556 "alignment of %qD is bigger than "
557 "original declaration", decl
);
561 inform (DECL_SOURCE_LOCATION (prevailing
->decl
),
562 "previously declared here");
564 VEC_free (tree
, heap
, mismatches
);
567 /* Helper to process the decl chain for the symbol table entry *SLOT. */
570 lto_symtab_merge_decls_1 (void **slot
, void *data ATTRIBUTE_UNUSED
)
572 lto_symtab_entry_t e
, prevailing
;
573 bool diagnosed_p
= false;
575 /* Compute the symbol resolutions. This is a no-op when using the
577 lto_symtab_resolve_symbols (slot
);
579 /* Find the prevailing decl. */
580 for (prevailing
= (lto_symtab_entry_t
) *slot
;
582 && prevailing
->resolution
!= LDPR_PREVAILING_DEF_IRONLY
583 && prevailing
->resolution
!= LDPR_PREVAILING_DEF_IRONLY_EXP
584 && prevailing
->resolution
!= LDPR_PREVAILING_DEF
;
585 prevailing
= prevailing
->next
)
588 /* Assert it's the only one. */
590 for (e
= prevailing
->next
; e
; e
= e
->next
)
592 if (e
->resolution
== LDPR_PREVAILING_DEF_IRONLY
593 || e
->resolution
== LDPR_PREVAILING_DEF_IRONLY_EXP
594 || e
->resolution
== LDPR_PREVAILING_DEF
)
595 fatal_error ("multiple prevailing defs for %qE",
596 DECL_NAME (prevailing
->decl
));
599 /* If there's not a prevailing symbol yet it's an external reference.
600 Happens a lot during ltrans. Choose the first symbol with a
601 cgraph or a varpool node. */
604 prevailing
= (lto_symtab_entry_t
) *slot
;
605 /* For functions choose one with a cgraph node. */
606 if (TREE_CODE (prevailing
->decl
) == FUNCTION_DECL
)
607 while (!prevailing
->node
609 prevailing
= prevailing
->next
;
610 /* For variables chose with a priority variant with vnode
611 attached (i.e. from unit where external declaration of
612 variable is actually used).
613 When there are multiple variants, chose one with size.
614 This is needed for C++ typeinfos, for example in
615 lto/20081204-1 there are typeifos in both units, just
616 one of them do have size. */
617 if (TREE_CODE (prevailing
->decl
) == VAR_DECL
)
619 for (e
= prevailing
->next
; e
; e
= e
->next
)
620 if ((!prevailing
->vnode
&& e
->vnode
)
621 || ((prevailing
->vnode
!= NULL
) == (e
->vnode
!= NULL
)
622 && !COMPLETE_TYPE_P (TREE_TYPE (prevailing
->decl
))
623 && COMPLETE_TYPE_P (TREE_TYPE (e
->decl
))))
628 /* Move it first in the list. */
629 if ((lto_symtab_entry_t
) *slot
!= prevailing
)
631 for (e
= (lto_symtab_entry_t
) *slot
; e
->next
!= prevailing
; e
= e
->next
)
633 e
->next
= prevailing
->next
;
634 prevailing
->next
= (lto_symtab_entry_t
) *slot
;
635 *slot
= (void *) prevailing
;
638 /* Record the prevailing variable. */
639 if (TREE_CODE (prevailing
->decl
) == VAR_DECL
)
640 VEC_safe_push (tree
, gc
, lto_global_var_decls
, prevailing
->decl
);
642 /* Diagnose mismatched objects. */
643 for (e
= prevailing
->next
; e
; e
= e
->next
)
645 if (TREE_CODE (prevailing
->decl
) == TREE_CODE (e
->decl
))
648 switch (TREE_CODE (prevailing
->decl
))
651 gcc_assert (TREE_CODE (e
->decl
) == FUNCTION_DECL
);
652 error_at (DECL_SOURCE_LOCATION (e
->decl
),
653 "variable %qD redeclared as function", prevailing
->decl
);
657 gcc_assert (TREE_CODE (e
->decl
) == VAR_DECL
);
658 error_at (DECL_SOURCE_LOCATION (e
->decl
),
659 "function %qD redeclared as variable", prevailing
->decl
);
669 inform (DECL_SOURCE_LOCATION (prevailing
->decl
),
670 "previously declared here");
672 /* Merge the chain to the single prevailing decl and diagnose
674 lto_symtab_merge_decls_2 (slot
, diagnosed_p
);
676 /* Store resolution decision into the callgraph.
677 In LTRANS don't overwrite information we stored into callgraph at
680 Do not bother to store guessed decisions. Generic code knows how
681 to handle UNKNOWN relocation well.
683 The problem with storing guessed decision is whether to use
684 PREVAILING_DEF, PREVAILING_DEF_IRONLY, PREVAILING_DEF_IRONLY_EXP.
685 First one would disable some whole program optimizations, while
686 ther second would imply to many whole program assumptions. */
687 if (prevailing
->node
&& !flag_ltrans
&& !prevailing
->guessed
)
688 prevailing
->node
->symbol
.resolution
= prevailing
->resolution
;
689 else if (prevailing
->vnode
&& !flag_ltrans
&& !prevailing
->guessed
)
690 prevailing
->vnode
->symbol
.resolution
= prevailing
->resolution
;
694 /* Resolve and merge all symbol table chains to a prevailing decl. */
697 lto_symtab_merge_decls (void)
699 lto_symtab_maybe_init_hash_table ();
700 htab_traverse (lto_symtab_identifiers
, lto_symtab_merge_decls_1
, NULL
);
703 /* Helper to process the decl chain for the symbol table entry *SLOT. */
706 lto_symtab_merge_cgraph_nodes_1 (void **slot
, void *data ATTRIBUTE_UNUSED
)
708 lto_symtab_entry_t e
, prevailing
= (lto_symtab_entry_t
) *slot
;
710 if (!prevailing
->next
)
713 /* Replace the cgraph node of each entry with the prevailing one. */
714 for (e
= prevailing
->next
; e
; e
= e
->next
)
718 /* In case we prevail funcion by an alias, we can run into case
719 that the alias has no cgraph node attached, since it was
720 previously unused. Create the node. */
721 if (!prevailing
->node
)
723 prevailing
->node
= cgraph_create_node (prevailing
->decl
);
724 prevailing
->node
->alias
= true;
726 lto_cgraph_replace_node (e
->node
, prevailing
->node
);
728 if (e
->vnode
!= NULL
)
730 if (!prevailing
->vnode
)
732 prevailing
->vnode
= varpool_node (prevailing
->decl
);
733 prevailing
->vnode
->alias
= true;
735 lto_varpool_replace_node (e
->vnode
, prevailing
->vnode
);
739 /* Drop all but the prevailing decl from the symtab. */
740 prevailing
->next
= NULL
;
745 /* Merge cgraph nodes according to the symbol merging done by
746 lto_symtab_merge_decls. */
749 lto_symtab_merge_cgraph_nodes (void)
751 struct cgraph_node
*node
;
752 struct varpool_node
*vnode
;
753 lto_symtab_maybe_init_hash_table ();
754 htab_traverse (lto_symtab_identifiers
, lto_symtab_merge_cgraph_nodes_1
, NULL
);
756 FOR_EACH_FUNCTION (node
)
757 if ((node
->thunk
.thunk_p
|| node
->alias
)
758 && node
->thunk
.alias
)
759 node
->thunk
.alias
= lto_symtab_prevailing_decl (node
->thunk
.alias
);
760 FOR_EACH_VARIABLE (vnode
)
762 vnode
->alias_of
= lto_symtab_prevailing_decl (vnode
->alias_of
);
765 /* Given the decl DECL, return the prevailing decl with the same name. */
768 lto_symtab_prevailing_decl (tree decl
)
770 lto_symtab_entry_t ret
;
772 /* Builtins and local symbols are their own prevailing decl. */
773 if (!TREE_PUBLIC (decl
) || is_builtin_fn (decl
))
776 /* DECL_ABSTRACTs are their own prevailng decl. */
777 if (TREE_CODE (decl
) == FUNCTION_DECL
&& DECL_ABSTRACT (decl
))
780 /* Ensure DECL_ASSEMBLER_NAME will not set assembler name. */
781 gcc_assert (DECL_ASSEMBLER_NAME_SET_P (decl
));
783 /* Walk through the list of candidates and return the one we merged to. */
784 ret
= lto_symtab_get ((*targetm
.asm_out
.mangle_assembler_name
)
785 (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl
))));
792 #include "gt-lto-symtab.h"