1 /* bfdlink.h -- header file for BFD link routines
2    Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
3    2003, 2004, 2005 Free Software Foundation, Inc.
4    Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support.
5 
6    This file is part of BFD, the Binary File Descriptor library.
7 
8    This program is free software; you can redistribute it and/or modify
9    it under the terms of the GNU General Public License as published by
10    the Free Software Foundation; either version 2 of the License, or
11    (at your option) any later version.
12 
13    This program is distributed in the hope that it will be useful,
14    but WITHOUT ANY WARRANTY; without even the implied warranty of
15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16    GNU General Public License for more details.
17 
18    You should have received a copy of the GNU General Public License
19    along with this program; if not, write to the Free Software
20    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
21 
22 #ifndef BFDLINK_H
23 #define BFDLINK_H
24 
25 /* Which symbols to strip during a link.  */
26 enum bfd_link_strip
27 {
28   strip_none,		/* Don't strip any symbols.  */
29   strip_debugger,	/* Strip debugging symbols.  */
30   strip_some,		/* keep_hash is the list of symbols to keep.  */
31   strip_all		/* Strip all symbols.  */
32 };
33 
34 /* Which local symbols to discard during a link.  This is irrelevant
35    if strip_all is used.  */
36 enum bfd_link_discard
37 {
38   discard_sec_merge,	/* Discard local temporary symbols in SEC_MERGE
39 			   sections.  */
40   discard_none,		/* Don't discard any locals.  */
41   discard_l,		/* Discard local temporary symbols.  */
42   discard_all		/* Discard all locals.  */
43 };
44 
45 /* Describes the type of hash table entry structure being used.
46    Different hash table structure have different fields and so
47    support different linking features.  */
48 enum bfd_link_hash_table_type
49   {
50     bfd_link_generic_hash_table,
51     bfd_link_elf_hash_table
52   };
53 
54 /* These are the possible types of an entry in the BFD link hash
55    table.  */
56 
57 enum bfd_link_hash_type
58 {
59   bfd_link_hash_new,		/* Symbol is new.  */
60   bfd_link_hash_undefined,	/* Symbol seen before, but undefined.  */
61   bfd_link_hash_undefweak,	/* Symbol is weak and undefined.  */
62   bfd_link_hash_defined,	/* Symbol is defined.  */
63   bfd_link_hash_defweak,	/* Symbol is weak and defined.  */
64   bfd_link_hash_common,		/* Symbol is common.  */
65   bfd_link_hash_indirect,	/* Symbol is an indirect link.  */
66   bfd_link_hash_warning		/* Like indirect, but warn if referenced.  */
67 };
68 
69 enum bfd_link_common_skip_ar_aymbols
70 {
71   bfd_link_common_skip_none,
72   bfd_link_common_skip_text,
73   bfd_link_common_skip_data,
74   bfd_link_common_skip_all
75 };
76 
77 /* The linking routines use a hash table which uses this structure for
78    its elements.  */
79 
80 struct bfd_link_hash_entry
81 {
82   /* Base hash table entry structure.  */
83   struct bfd_hash_entry root;
84 
85   /* Type of this entry.  */
86   enum bfd_link_hash_type type;
87 
88   /* A union of information depending upon the type.  */
89   union
90     {
91       /* Nothing is kept for bfd_hash_new.  */
92       /* bfd_link_hash_undefined, bfd_link_hash_undefweak.  */
93       struct
94 	{
95 	  /* Undefined and common symbols are kept in a linked list through
96 	     this field.  This field is present in all of the union element
97 	     so that we don't need to remove entries from the list when we
98 	     change their type.  Removing entries would either require the
99 	     list to be doubly linked, which would waste more memory, or
100 	     require a traversal.  When an undefined or common symbol is
101 	     created, it should be added to this list, the head of which is in
102 	     the link hash table itself.  As symbols are defined, they need
103 	     not be removed from the list; anything which reads the list must
104 	     doublecheck the symbol type.
105 
106 	     Weak symbols are not kept on this list.
107 
108 	     Defined and defweak symbols use this field as a reference marker.
109 	     If the field is not NULL, or this structure is the tail of the
110 	     undefined symbol list, the symbol has been referenced.  If the
111 	     symbol is undefined and becomes defined, this field will
112 	     automatically be non-NULL since the symbol will have been on the
113 	     undefined symbol list.  */
114 	  struct bfd_link_hash_entry *next;
115 	  bfd *abfd;		/* BFD symbol was found in.  */
116 	  bfd *weak;		/* BFD weak symbol was found in.  */
117 	} undef;
118       /* bfd_link_hash_defined, bfd_link_hash_defweak.  */
119       struct
120 	{
121 	  struct bfd_link_hash_entry *next;
122 	  asection *section;	/* Symbol section.  */
123 	  bfd_vma value;	/* Symbol value.  */
124 	} def;
125       /* bfd_link_hash_indirect, bfd_link_hash_warning.  */
126       struct
127 	{
128 	  struct bfd_link_hash_entry *next;
129 	  struct bfd_link_hash_entry *link;	/* Real symbol.  */
130 	  const char *warning;	/* Warning (bfd_link_hash_warning only).  */
131 	} i;
132       /* bfd_link_hash_common.  */
133       struct
134 	{
135 	  struct bfd_link_hash_entry *next;
136 	  /* The linker needs to know three things about common
137 	     symbols: the size, the alignment, and the section in
138 	     which the symbol should be placed.  We store the size
139 	     here, and we allocate a small structure to hold the
140 	     section and the alignment.  The alignment is stored as a
141 	     power of two.  We don't store all the information
142 	     directly because we don't want to increase the size of
143 	     the union; this structure is a major space user in the
144 	     linker.  */
145 	  struct bfd_link_hash_common_entry
146 	    {
147 	      unsigned int alignment_power;	/* Alignment.  */
148 	      asection *section;		/* Symbol section.  */
149 	    } *p;
150 	  bfd_size_type size;	/* Common symbol size.  */
151 	} c;
152     } u;
153 };
154 
155 /* This is the link hash table.  It is a derived class of
156    bfd_hash_table.  */
157 
158 struct bfd_link_hash_table
159 {
160   /* The hash table itself.  */
161   struct bfd_hash_table table;
162   /* The back end which created this hash table.  This indicates the
163      type of the entries in the hash table, which is sometimes
164      important information when linking object files of different
165      types together.  */
166   const bfd_target *creator;
167   /* A linked list of undefined and common symbols, linked through the
168      next field in the bfd_link_hash_entry structure.  */
169   struct bfd_link_hash_entry *undefs;
170   /* Entries are added to the tail of the undefs list.  */
171   struct bfd_link_hash_entry *undefs_tail;
172   /* The type of the link hash table.  */
173   enum bfd_link_hash_table_type type;
174 };
175 
176 /* Look up an entry in a link hash table.  If FOLLOW is TRUE, this
177    follows bfd_link_hash_indirect and bfd_link_hash_warning links to
178    the real symbol.  */
179 extern struct bfd_link_hash_entry *bfd_link_hash_lookup
180   (struct bfd_link_hash_table *, const char *, bfd_boolean create,
181    bfd_boolean copy, bfd_boolean follow);
182 
183 /* Look up an entry in the main linker hash table if the symbol might
184    be wrapped.  This should only be used for references to an
185    undefined symbol, not for definitions of a symbol.  */
186 
187 extern struct bfd_link_hash_entry *bfd_wrapped_link_hash_lookup
188   (bfd *, struct bfd_link_info *, const char *, bfd_boolean,
189    bfd_boolean, bfd_boolean);
190 
191 /* Traverse a link hash table.  */
192 extern void bfd_link_hash_traverse
193   (struct bfd_link_hash_table *,
194     bfd_boolean (*) (struct bfd_link_hash_entry *, void *),
195     void *);
196 
197 /* Add an entry to the undefs list.  */
198 extern void bfd_link_add_undef
199   (struct bfd_link_hash_table *, struct bfd_link_hash_entry *);
200 
201 /* Remove symbols from the undefs list that don't belong there.  */
202 extern void bfd_link_repair_undef_list
203   (struct bfd_link_hash_table *table);
204 
205 struct bfd_sym_chain
206 {
207   struct bfd_sym_chain *next;
208   const char *name;
209 };
210 
211 /* How to handle unresolved symbols.
212    There are four possibilities which are enumerated below:  */
213 enum report_method
214 {
215   /* This is the initial value when then link_info structure is created.
216      It allows the various stages of the linker to determine whether they
217      allowed to set the value.  */
218   RM_NOT_YET_SET = 0,
219   RM_IGNORE,
220   RM_GENERATE_WARNING,
221   RM_GENERATE_ERROR
222 };
223 
224 /* This structure holds all the information needed to communicate
225    between BFD and the linker when doing a link.  */
226 
227 struct bfd_link_info
228 {
229   /* TRUE if BFD should generate a relocatable object file.  */
230   unsigned int relocatable: 1;
231 
232   /* TRUE if BFD should generate relocation information in the final
233      executable.  */
234   unsigned int emitrelocations: 1;
235 
236   /* TRUE if BFD should generate a "task linked" object file,
237      similar to relocatable but also with globals converted to
238      statics.  */
239   unsigned int task_link: 1;
240 
241   /* TRUE if BFD should generate a shared object.  */
242   unsigned int shared: 1;
243 
244   /* TRUE if BFD should pre-bind symbols in a shared object.  */
245   unsigned int symbolic: 1;
246 
247   /* TRUE if BFD should export all symbols in the dynamic symbol table
248      of an executable, rather than only those used.  */
249   unsigned int export_dynamic: 1;
250 
251   /* TRUE if shared objects should be linked directly, not shared.  */
252   unsigned int static_link: 1;
253 
254   /* TRUE if the output file should be in a traditional format.  This
255      is equivalent to the setting of the BFD_TRADITIONAL_FORMAT flag
256      on the output file, but may be checked when reading the input
257      files.  */
258   unsigned int traditional_format: 1;
259 
260   /* TRUE if we want to produced optimized output files.  This might
261      need much more time and therefore must be explicitly selected.  */
262   unsigned int optimize: 1;
263 
264   /* TRUE if ok to have multiple definition.  */
265   unsigned int allow_multiple_definition: 1;
266 
267   /* TRUE if output program should be marked to request W^X permission */
268   unsigned int wxneeded: 1;
269 
270   /* TRUE if ok to have version with no definition.  */
271   unsigned int allow_undefined_version: 1;
272 
273   /* TRUE if a default symbol version should be created and used for
274      exported symbols.  */
275   unsigned int create_default_symver: 1;
276 
277   /* TRUE if a default symbol version should be created and used for
278      imported symbols.  */
279   unsigned int default_imported_symver: 1;
280 
281   /* TRUE if symbols should be retained in memory, FALSE if they
282      should be freed and reread.  */
283   unsigned int keep_memory: 1;
284 
285   /* TRUE if every symbol should be reported back via the notice
286      callback.  */
287   unsigned int notice_all: 1;
288 
289   /* TRUE if executable should not contain copy relocs.
290      Setting this true may result in a non-sharable text segment.  */
291   unsigned int nocopyreloc: 1;
292 
293   /* TRUE if the new ELF dynamic tags are enabled. */
294   unsigned int new_dtags: 1;
295 
296   /* TRUE if non-PLT relocs should be merged into one reloc section
297      and sorted so that relocs against the same symbol come together.  */
298   unsigned int combreloc: 1;
299 
300   /* TRUE if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment
301      should be created.  */
302   unsigned int eh_frame_hdr: 1;
303 
304   /* TRUE if global symbols in discarded sections should be stripped.  */
305   unsigned int strip_discarded: 1;
306 
307   /* TRUE if generating a position independent executable.  */
308   unsigned int pie: 1;
309 
310   /* TRUE if generating an executable, position independent or not.  */
311   unsigned int executable : 1;
312 
313   /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W|PF_X
314      flags.  */
315   unsigned int execstack: 1;
316 
317   /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W
318      flags.  */
319   unsigned int noexecstack: 1;
320 
321   /* TRUE if PT_GNU_RELRO segment should be created.  */
322   unsigned int relro: 1;
323 
324   /* TRUE if we should warn when adding a DT_TEXTREL to a shared object.  */
325   unsigned int warn_shared_textrel: 1;
326 
327   /* TRUE if unreferenced sections should be removed.  */
328   unsigned int gc_sections: 1;
329 
330   /* If TRUE reduce memory overheads, at the expense of speed. This will
331      cause map file generation to use an O(N^2) algorithm and disable
332      caching ELF symbol buffer.  */
333   unsigned int reduce_memory_overheads: 1;
334 
335   /* What to do with unresolved symbols in an object file.
336      When producing executables the default is GENERATE_ERROR.
337      When producing shared libraries the default is IGNORE.  The
338      assumption with shared libraries is that the reference will be
339      resolved at load/execution time.  */
340   enum report_method unresolved_syms_in_objects;
341 
342   /* What to do with unresolved symbols in a shared library.
343      The same defaults apply.  */
344   enum report_method unresolved_syms_in_shared_libs;
345 
346   /* Which symbols to strip.  */
347   enum bfd_link_strip strip;
348 
349   /* Which local symbols to discard.  */
350   enum bfd_link_discard discard;
351 
352   /* Criteria for skipping symbols when detemining
353      whether to include an object from an archive. */
354   enum bfd_link_common_skip_ar_aymbols common_skip_ar_aymbols;
355 
356   /* Char that may appear as the first char of a symbol, but should be
357      skipped (like symbol_leading_char) when looking up symbols in
358      wrap_hash.  Used by PowerPC Linux for 'dot' symbols.  */
359   char wrap_char;
360 
361   /* Function callbacks.  */
362   const struct bfd_link_callbacks *callbacks;
363 
364   /* Hash table handled by BFD.  */
365   struct bfd_link_hash_table *hash;
366 
367   /* Hash table of symbols to keep.  This is NULL unless strip is
368      strip_some.  */
369   struct bfd_hash_table *keep_hash;
370 
371   /* Hash table of symbols to report back via the notice callback.  If
372      this is NULL, and notice_all is FALSE, then no symbols are
373      reported back.  */
374   struct bfd_hash_table *notice_hash;
375 
376   /* Hash table of symbols which are being wrapped (the --wrap linker
377      option).  If this is NULL, no symbols are being wrapped.  */
378   struct bfd_hash_table *wrap_hash;
379 
380   /* The list of input BFD's involved in the link.  These are chained
381      together via the link_next field.  */
382   bfd *input_bfds;
383 
384   /* If a symbol should be created for each input BFD, this is section
385      where those symbols should be placed.  It must be a section in
386      the output BFD.  It may be NULL, in which case no such symbols
387      will be created.  This is to support CREATE_OBJECT_SYMBOLS in the
388      linker command language.  */
389   asection *create_object_symbols_section;
390 
391   /* List of global symbol names that are starting points for marking
392      sections against garbage collection.  */
393   struct bfd_sym_chain *gc_sym_list;
394 
395   /* If a base output file is wanted, then this points to it */
396   void *base_file;
397 
398   /* The function to call when the executable or shared object is
399      loaded.  */
400   const char *init_function;
401 
402   /* The function to call when the executable or shared object is
403      unloaded.  */
404   const char *fini_function;
405 
406   /* Number of relaxation passes.  Usually only one relaxation pass
407      is needed.  But a backend can have as many relaxation passes as
408      necessary.  During bfd_relax_section call, it is set to the
409      current pass, starting from 0.  */
410   int relax_pass;
411 
412   /* Non-zero if auto-import thunks for DATA items in pei386 DLLs
413      should be generated/linked against.  Set to 1 if this feature
414      is explicitly requested by the user, -1 if enabled by default.  */
415   int pei386_auto_import;
416 
417   /* Non-zero if runtime relocs for DATA items with non-zero addends
418      in pei386 DLLs should be generated.  Set to 1 if this feature
419      is explicitly requested by the user, -1 if enabled by default.  */
420   int pei386_runtime_pseudo_reloc;
421 
422   /* How many spare .dynamic DT_NULL entries should be added?  */
423   unsigned int spare_dynamic_tags;
424 
425   /* May be used to set DT_FLAGS for ELF. */
426   bfd_vma flags;
427 
428   /* May be used to set DT_FLAGS_1 for ELF. */
429   bfd_vma flags_1;
430 
431   /* Start and end of RELRO region.  */
432   bfd_vma relro_start, relro_end;
433 };
434 
435 /* This structures holds a set of callback functions.  These are
436    called by the BFD linker routines.  Except for einfo, the first
437    argument to each callback function is the bfd_link_info structure
438    being used and each function returns a boolean value.  If the
439    function returns FALSE, then the BFD function which called it should
440    return with a failure indication.  */
441 
442 struct bfd_link_callbacks
443 {
444   /* A function which is called when an object is added from an
445      archive.  ABFD is the archive element being added.  NAME is the
446      name of the symbol which caused the archive element to be pulled
447      in.  */
448   bfd_boolean (*add_archive_element)
449     (struct bfd_link_info *, bfd *abfd, const char *name);
450   /* A function which is called when a symbol is found with multiple
451      definitions.  NAME is the symbol which is defined multiple times.
452      OBFD is the old BFD, OSEC is the old section, OVAL is the old
453      value, NBFD is the new BFD, NSEC is the new section, and NVAL is
454      the new value.  OBFD may be NULL.  OSEC and NSEC may be
455      bfd_com_section or bfd_ind_section.  */
456   bfd_boolean (*multiple_definition)
457     (struct bfd_link_info *, const char *name,
458      bfd *obfd, asection *osec, bfd_vma oval,
459      bfd *nbfd, asection *nsec, bfd_vma nval);
460   /* A function which is called when a common symbol is defined
461      multiple times.  NAME is the symbol appearing multiple times.
462      OBFD is the BFD of the existing symbol; it may be NULL if this is
463      not known.  OTYPE is the type of the existing symbol, which may
464      be bfd_link_hash_defined, bfd_link_hash_defweak,
465      bfd_link_hash_common, or bfd_link_hash_indirect.  If OTYPE is
466      bfd_link_hash_common, OSIZE is the size of the existing symbol.
467      NBFD is the BFD of the new symbol.  NTYPE is the type of the new
468      symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or
469      bfd_link_hash_indirect.  If NTYPE is bfd_link_hash_common, NSIZE
470      is the size of the new symbol.  */
471   bfd_boolean (*multiple_common)
472     (struct bfd_link_info *, const char *name,
473      bfd *obfd, enum bfd_link_hash_type otype, bfd_vma osize,
474      bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize);
475   /* A function which is called to add a symbol to a set.  ENTRY is
476      the link hash table entry for the set itself (e.g.,
477      __CTOR_LIST__).  RELOC is the relocation to use for an entry in
478      the set when generating a relocatable file, and is also used to
479      get the size of the entry when generating an executable file.
480      ABFD, SEC and VALUE identify the value to add to the set.  */
481   bfd_boolean (*add_to_set)
482     (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
483      bfd_reloc_code_real_type reloc, bfd *abfd, asection *sec, bfd_vma value);
484   /* A function which is called when the name of a g++ constructor or
485      destructor is found.  This is only called by some object file
486      formats.  CONSTRUCTOR is TRUE for a constructor, FALSE for a
487      destructor.  This will use BFD_RELOC_CTOR when generating a
488      relocatable file.  NAME is the name of the symbol found.  ABFD,
489      SECTION and VALUE are the value of the symbol.  */
490   bfd_boolean (*constructor)
491     (struct bfd_link_info *, bfd_boolean constructor, const char *name,
492      bfd *abfd, asection *sec, bfd_vma value);
493   /* A function which is called to issue a linker warning.  For
494      example, this is called when there is a reference to a warning
495      symbol.  WARNING is the warning to be issued.  SYMBOL is the name
496      of the symbol which triggered the warning; it may be NULL if
497      there is none.  ABFD, SECTION and ADDRESS identify the location
498      which trigerred the warning; either ABFD or SECTION or both may
499      be NULL if the location is not known.  */
500   bfd_boolean (*warning)
501     (struct bfd_link_info *, const char *warning, const char *symbol,
502      bfd *abfd, asection *section, bfd_vma address);
503   /* A function which is called when a relocation is attempted against
504      an undefined symbol.  NAME is the symbol which is undefined.
505      ABFD, SECTION and ADDRESS identify the location from which the
506      reference is made. FATAL indicates whether an undefined symbol is
507      a fatal error or not. In some cases SECTION may be NULL.  */
508   bfd_boolean (*undefined_symbol)
509     (struct bfd_link_info *, const char *name, bfd *abfd,
510      asection *section, bfd_vma address, bfd_boolean fatal);
511   /* A function which is called when a reloc overflow occurs. ENTRY is
512      the link hash table entry for the symbol the reloc is against.
513      NAME is the name of the local symbol or section the reloc is
514      against, RELOC_NAME is the name of the relocation, and ADDEND is
515      any addend that is used.  ABFD, SECTION and ADDRESS identify the
516      location at which the overflow occurs; if this is the result of a
517      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
518      ABFD will be NULL.  */
519   bfd_boolean (*reloc_overflow)
520     (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
521      const char *name, const char *reloc_name, bfd_vma addend,
522      bfd *abfd, asection *section, bfd_vma address);
523   /* A function which is called when a dangerous reloc is performed.
524      MESSAGE is an appropriate message.
525      ABFD, SECTION and ADDRESS identify the location at which the
526      problem occurred; if this is the result of a
527      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
528      ABFD will be NULL.  */
529   bfd_boolean (*reloc_dangerous)
530     (struct bfd_link_info *, const char *message,
531      bfd *abfd, asection *section, bfd_vma address);
532   /* A function which is called when a reloc is found to be attached
533      to a symbol which is not being written out.  NAME is the name of
534      the symbol.  ABFD, SECTION and ADDRESS identify the location of
535      the reloc; if this is the result of a
536      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
537      ABFD will be NULL.  */
538   bfd_boolean (*unattached_reloc)
539     (struct bfd_link_info *, const char *name,
540      bfd *abfd, asection *section, bfd_vma address);
541   /* A function which is called when a symbol in notice_hash is
542      defined or referenced.  NAME is the symbol.  ABFD, SECTION and
543      ADDRESS are the value of the symbol.  If SECTION is
544      bfd_und_section, this is a reference.  */
545   bfd_boolean (*notice)
546     (struct bfd_link_info *, const char *name,
547      bfd *abfd, asection *section, bfd_vma address);
548   /* General link info message.  */
549   void (*einfo)
550     (const char *fmt, ...);
551 };
552 
553 /* The linker builds link_order structures which tell the code how to
554    include input data in the output file.  */
555 
556 /* These are the types of link_order structures.  */
557 
558 enum bfd_link_order_type
559 {
560   bfd_undefined_link_order,	/* Undefined.  */
561   bfd_indirect_link_order,	/* Built from a section.  */
562   bfd_data_link_order,		/* Set to explicit data.  */
563   bfd_section_reloc_link_order,	/* Relocate against a section.  */
564   bfd_symbol_reloc_link_order	/* Relocate against a symbol.  */
565 };
566 
567 /* This is the link_order structure itself.  These form a chain
568    attached to the output section whose contents they are describing.  */
569 
570 struct bfd_link_order
571 {
572   /* Next link_order in chain.  */
573   struct bfd_link_order *next;
574   /* Type of link_order.  */
575   enum bfd_link_order_type type;
576   /* Offset within output section.  */
577   bfd_vma offset;
578   /* Size within output section.  */
579   bfd_size_type size;
580   /* Type specific information.  */
581   union
582     {
583       struct
584 	{
585 	  /* Section to include.  If this is used, then
586 	     section->output_section must be the section the
587 	     link_order is attached to, section->output_offset must
588 	     equal the link_order offset field, and section->size
589 	     must equal the link_order size field.  Maybe these
590 	     restrictions should be relaxed someday.  */
591 	  asection *section;
592 	} indirect;
593       struct
594 	{
595 	  /* Size of contents, or zero when contents size == size
596 	     within output section.
597 	     A non-zero value allows filling of the output section
598 	     with an arbitrary repeated pattern.  */
599 	  unsigned int size;
600 	  /* Data to put into file.  */
601 	  bfd_byte *contents;
602 	} data;
603       struct
604 	{
605 	  /* Description of reloc to generate.  Used for
606 	     bfd_section_reloc_link_order and
607 	     bfd_symbol_reloc_link_order.  */
608 	  struct bfd_link_order_reloc *p;
609 	} reloc;
610     } u;
611 };
612 
613 /* A linker order of type bfd_section_reloc_link_order or
614    bfd_symbol_reloc_link_order means to create a reloc against a
615    section or symbol, respectively.  This is used to implement -Ur to
616    generate relocs for the constructor tables.  The
617    bfd_link_order_reloc structure describes the reloc that BFD should
618    create.  It is similar to a arelent, but I didn't use arelent
619    because the linker does not know anything about most symbols, and
620    any asymbol structure it creates will be partially meaningless.
621    This information could logically be in the bfd_link_order struct,
622    but I didn't want to waste the space since these types of relocs
623    are relatively rare.  */
624 
625 struct bfd_link_order_reloc
626 {
627   /* Reloc type.  */
628   bfd_reloc_code_real_type reloc;
629 
630   union
631     {
632       /* For type bfd_section_reloc_link_order, this is the section
633 	 the reloc should be against.  This must be a section in the
634 	 output BFD, not any of the input BFDs.  */
635       asection *section;
636       /* For type bfd_symbol_reloc_link_order, this is the name of the
637 	 symbol the reloc should be against.  */
638       const char *name;
639     } u;
640 
641   /* Addend to use.  The object file should contain zero.  The BFD
642      backend is responsible for filling in the contents of the object
643      file correctly.  For some object file formats (e.g., COFF) the
644      addend must be stored into in the object file, and for some
645      (e.g., SPARC a.out) it is kept in the reloc.  */
646   bfd_vma addend;
647 };
648 
649 /* Allocate a new link_order for a section.  */
650 extern struct bfd_link_order *bfd_new_link_order (bfd *, asection *);
651 
652 /* These structures are used to describe version information for the
653    ELF linker.  These structures could be manipulated entirely inside
654    BFD, but it would be a pain.  Instead, the regular linker sets up
655    these structures, and then passes them into BFD.  */
656 
657 /* Glob pattern for a version.  */
658 
659 struct bfd_elf_version_expr
660 {
661   /* Next glob pattern for this version.  */
662   struct bfd_elf_version_expr *next;
663   /* Glob pattern.  */
664   const char *pattern;
665   /* NULL for a glob pattern, otherwise a straight symbol.  */
666   const char *symbol;
667   /* Defined by ".symver".  */
668   unsigned int symver : 1;
669   /* Defined by version script.  */
670   unsigned int script : 1;
671   /* Pattern type.  */
672 #define BFD_ELF_VERSION_C_TYPE		1
673 #define BFD_ELF_VERSION_CXX_TYPE	2
674 #define BFD_ELF_VERSION_JAVA_TYPE	4
675   unsigned int mask : 3;
676 };
677 
678 struct bfd_elf_version_expr_head
679 {
680   /* List of all patterns, both wildcards and non-wildcards.  */
681   struct bfd_elf_version_expr *list;
682   /* Hash table for non-wildcards.  */
683   void *htab;
684   /* Remaining patterns.  */
685   struct bfd_elf_version_expr *remaining;
686   /* What kind of pattern types are present in list (bitmask).  */
687   unsigned int mask;
688 };
689 
690 /* Version dependencies.  */
691 
692 struct bfd_elf_version_deps
693 {
694   /* Next dependency for this version.  */
695   struct bfd_elf_version_deps *next;
696   /* The version which this version depends upon.  */
697   struct bfd_elf_version_tree *version_needed;
698 };
699 
700 /* A node in the version tree.  */
701 
702 struct bfd_elf_version_tree
703 {
704   /* Next version.  */
705   struct bfd_elf_version_tree *next;
706   /* Name of this version.  */
707   const char *name;
708   /* Version number.  */
709   unsigned int vernum;
710   /* Regular expressions for global symbols in this version.  */
711   struct bfd_elf_version_expr_head globals;
712   /* Regular expressions for local symbols in this version.  */
713   struct bfd_elf_version_expr_head locals;
714   /* List of versions which this version depends upon.  */
715   struct bfd_elf_version_deps *deps;
716   /* Index of the version name.  This is used within BFD.  */
717   unsigned int name_indx;
718   /* Whether this version tree was used.  This is used within BFD.  */
719   int used;
720   /* Matching hook.  */
721   struct bfd_elf_version_expr *(*match)
722     (struct bfd_elf_version_expr_head *head,
723      struct bfd_elf_version_expr *prev, const char *sym);
724 };
725 
726 #endif
727