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1 /* ldlang.h - linker command language support
2    Copyright (C) 1991-2014 Free Software Foundation, Inc.
3 
4    This file is part of the GNU Binutils.
5 
6    This program is free software; you can redistribute it and/or modify
7    it under the terms of the GNU General Public License as published by
8    the Free Software Foundation; either version 3 of the License, or
9    (at your option) any later version.
10 
11    This program is distributed in the hope that it will be useful,
12    but WITHOUT ANY WARRANTY; without even the implied warranty of
13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14    GNU General Public License for more details.
15 
16    You should have received a copy of the GNU General Public License
17    along with this program; if not, write to the Free Software
18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
19    MA 02110-1301, USA.  */
20 
21 #ifndef LDLANG_H
22 #define LDLANG_H
23 
24 #define DEFAULT_MEMORY_REGION   "*default*"
25 
26 typedef enum
27 {
28   lang_input_file_is_l_enum,
29   lang_input_file_is_symbols_only_enum,
30   lang_input_file_is_marker_enum,
31   lang_input_file_is_fake_enum,
32   lang_input_file_is_search_file_enum,
33   lang_input_file_is_file_enum
34 } lang_input_file_enum_type;
35 
36 struct _fill_type
37 {
38   size_t size;
39   unsigned char data[1];
40 };
41 
42 typedef struct statement_list
43 {
44   union lang_statement_union *  head;
45   union lang_statement_union ** tail;
46 } lang_statement_list_type;
47 
48 typedef struct memory_region_name_struct
49 {
50   const char * name;
51   struct memory_region_name_struct * next;
52 } lang_memory_region_name;
53 
54 typedef struct memory_region_struct
55 {
56   lang_memory_region_name name_list;
57   struct memory_region_struct *next;
58   bfd_vma origin;
59   bfd_size_type length;
60   bfd_vma current;
61   union lang_statement_union *last_os;
62   flagword flags;
63   flagword not_flags;
64   bfd_boolean had_full_message;
65 } lang_memory_region_type;
66 
67 enum statement_enum
68 {
69   lang_output_section_statement_enum,
70   lang_assignment_statement_enum,
71   lang_input_statement_enum,
72   lang_address_statement_enum,
73   lang_wild_statement_enum,
74   lang_input_section_enum,
75   lang_object_symbols_statement_enum,
76   lang_fill_statement_enum,
77   lang_data_statement_enum,
78   lang_reloc_statement_enum,
79   lang_target_statement_enum,
80   lang_output_statement_enum,
81   lang_padding_statement_enum,
82   lang_group_statement_enum,
83   lang_insert_statement_enum,
84   lang_constructors_statement_enum
85 };
86 
87 typedef struct lang_statement_header_struct
88 {
89   union lang_statement_union *next;
90   enum statement_enum type;
91 } lang_statement_header_type;
92 
93 typedef struct
94 {
95   lang_statement_header_type header;
96   union etree_union *exp;
97 } lang_assignment_statement_type;
98 
99 typedef struct lang_target_statement_struct
100 {
101   lang_statement_header_type header;
102   const char *target;
103 } lang_target_statement_type;
104 
105 typedef struct lang_output_statement_struct
106 {
107   lang_statement_header_type header;
108   const char *name;
109 } lang_output_statement_type;
110 
111 /* Section types specified in a linker script.  */
112 
113 enum section_type
114 {
115   normal_section,
116   overlay_section,
117   noload_section,
118   noalloc_section
119 };
120 
121 /* This structure holds a list of program headers describing
122    segments in which this section should be placed.  */
123 
124 typedef struct lang_output_section_phdr_list
125 {
126   struct lang_output_section_phdr_list *next;
127   const char *name;
128   bfd_boolean used;
129 } lang_output_section_phdr_list;
130 
131 typedef struct lang_output_section_statement_struct
132 {
133   lang_statement_header_type header;
134   lang_statement_list_type children;
135   struct lang_output_section_statement_struct *next;
136   struct lang_output_section_statement_struct *prev;
137   const char *name;
138   asection *bfd_section;
139   lang_memory_region_type *region;
140   lang_memory_region_type *lma_region;
141   fill_type *fill;
142   union etree_union *addr_tree;
143   union etree_union *load_base;
144 
145   /* If non-null, an expression to evaluate after setting the section's
146      size.  The expression is evaluated inside REGION (above) with '.'
147      set to the end of the section.  Used in the last overlay section
148      to move '.' past all the overlaid sections.  */
149   union etree_union *update_dot_tree;
150 
151   lang_output_section_phdr_list *phdrs;
152 
153   unsigned int block_value;
154   int subsection_alignment;	/* Alignment of components.  */
155   int section_alignment;	/* Alignment of start of section.  */
156   int constraint;
157   flagword flags;
158   enum section_type sectype;
159   unsigned int processed_vma : 1;
160   unsigned int processed_lma : 1;
161   unsigned int all_input_readonly : 1;
162   /* If this section should be ignored.  */
163   unsigned int ignored : 1;
164   /* If this section should update "dot".  Prevents section being ignored.  */
165   unsigned int update_dot : 1;
166   /* If this section uses the alignment of its input sections.  */
167   unsigned int align_lma_with_input : 1;
168 } lang_output_section_statement_type;
169 
170 typedef struct
171 {
172   lang_statement_header_type header;
173 } lang_common_statement_type;
174 
175 typedef struct
176 {
177   lang_statement_header_type header;
178 } lang_object_symbols_statement_type;
179 
180 typedef struct
181 {
182   lang_statement_header_type header;
183   fill_type *fill;
184   int size;
185   asection *output_section;
186 } lang_fill_statement_type;
187 
188 typedef struct
189 {
190   lang_statement_header_type header;
191   unsigned int type;
192   union etree_union *exp;
193   bfd_vma value;
194   asection *output_section;
195   bfd_vma output_offset;
196 } lang_data_statement_type;
197 
198 /* Generate a reloc in the output file.  */
199 
200 typedef struct
201 {
202   lang_statement_header_type header;
203 
204   /* Reloc to generate.  */
205   bfd_reloc_code_real_type reloc;
206 
207   /* Reloc howto structure.  */
208   reloc_howto_type *howto;
209 
210   /* Section to generate reloc against.
211      Exactly one of section and name must be NULL.  */
212   asection *section;
213 
214   /* Name of symbol to generate reloc against.
215      Exactly one of section and name must be NULL.  */
216   const char *name;
217 
218   /* Expression for addend.  */
219   union etree_union *addend_exp;
220 
221   /* Resolved addend.  */
222   bfd_vma addend_value;
223 
224   /* Output section where reloc should be performed.  */
225   asection *output_section;
226 
227   /* Offset within output section.  */
228   bfd_vma output_offset;
229 } lang_reloc_statement_type;
230 
231 struct lang_input_statement_flags
232 {
233   /* 1 means this file was specified in a -l option.  */
234   unsigned int maybe_archive : 1;
235 
236   /* 1 means this file was specified in a -l:namespec option.  */
237   unsigned int full_name_provided : 1;
238 
239   /* 1 means search a set of directories for this file.  */
240   unsigned int search_dirs : 1;
241 
242   /* 1 means this was found when processing a script in the sysroot.  */
243   unsigned int sysrooted : 1;
244 
245   /* 1 means this is base file of incremental load.
246      Do not load this file's text or data.
247      Also default text_start to after this file's bss.  */
248   unsigned int just_syms : 1;
249 
250   /* Whether to search for this entry as a dynamic archive.  */
251   unsigned int dynamic : 1;
252 
253   /* Set if a DT_NEEDED tag should be added not just for the dynamic library
254      explicitly given by this entry but also for any dynamic libraries in
255      this entry's needed list.  */
256   unsigned int add_DT_NEEDED_for_dynamic : 1;
257 
258   /* Set if this entry should cause a DT_NEEDED tag only when some
259      regular file references its symbols (ie. --as-needed is in effect).  */
260   unsigned int add_DT_NEEDED_for_regular : 1;
261 
262   /* Whether to include the entire contents of an archive.  */
263   unsigned int whole_archive : 1;
264 
265   /* Set when bfd opening is successful.  */
266   unsigned int loaded : 1;
267 
268   unsigned int real : 1;
269 
270   /* Set if the file does not exist.  */
271   unsigned int missing_file : 1;
272 
273   /* Set if reloading an archive or --as-needed lib.  */
274   unsigned int reload : 1;
275 
276 #ifdef ENABLE_PLUGINS
277   /* Set if the file was claimed by a plugin.  */
278   unsigned int claimed : 1;
279 
280   /* Set if the file was claimed from an archive.  */
281   unsigned int claim_archive : 1;
282 #endif /* ENABLE_PLUGINS */
283 
284   /* Head of list of pushed flags.  */
285   struct lang_input_statement_flags *pushed;
286 };
287 
288 typedef struct lang_input_statement_struct
289 {
290   lang_statement_header_type header;
291   /* Name of this file.  */
292   const char *filename;
293   /* Name to use for the symbol giving address of text start.
294      Usually the same as filename, but for a file spec'd with
295      -l this is the -l switch itself rather than the filename.  */
296   const char *local_sym_name;
297 
298   bfd *the_bfd;
299 
300   struct flag_info *section_flag_list;
301 
302   /* Point to the next file - whatever it is, wanders up and down
303      archives */
304   union lang_statement_union *next;
305 
306   /* Point to the next file, but skips archive contents.  */
307   union lang_statement_union *next_real_file;
308 
309   const char *target;
310 
311   struct lang_input_statement_flags flags;
312 } lang_input_statement_type;
313 
314 typedef struct
315 {
316   lang_statement_header_type header;
317   asection *section;
318 } lang_input_section_type;
319 
320 struct map_symbol_def {
321   struct bfd_link_hash_entry *entry;
322   struct map_symbol_def *next;
323 };
324 
325 /* For input sections, when writing a map file: head / tail of a linked
326    list of hash table entries for symbols defined in this section.  */
327 typedef struct input_section_userdata_struct
328 {
329   struct map_symbol_def *map_symbol_def_head;
330   struct map_symbol_def **map_symbol_def_tail;
331   unsigned long map_symbol_def_count;
332 } input_section_userdata_type;
333 
334 #define get_userdata(x) ((x)->userdata)
335 
336 
337 typedef struct lang_wild_statement_struct lang_wild_statement_type;
338 
339 typedef void (*callback_t) (lang_wild_statement_type *, struct wildcard_list *,
340 			    asection *, struct flag_info *,
341 			    lang_input_statement_type *, void *);
342 
343 typedef void (*walk_wild_section_handler_t) (lang_wild_statement_type *,
344 					     lang_input_statement_type *,
345 					     callback_t callback,
346 					     void *data);
347 
348 typedef bfd_boolean (*lang_match_sec_type_func) (bfd *, const asection *,
349 						 bfd *, const asection *);
350 
351 /* Binary search tree structure to efficiently sort sections by
352    name.  */
353 typedef struct lang_section_bst
354 {
355   asection *section;
356   struct lang_section_bst *left;
357   struct lang_section_bst *right;
358 } lang_section_bst_type;
359 
360 struct lang_wild_statement_struct
361 {
362   lang_statement_header_type header;
363   const char *filename;
364   bfd_boolean filenames_sorted;
365   struct wildcard_list *section_list;
366   bfd_boolean keep_sections;
367   lang_statement_list_type children;
368 
369   walk_wild_section_handler_t walk_wild_section_handler;
370   struct wildcard_list *handler_data[4];
371   lang_section_bst_type *tree;
372   struct flag_info *section_flag_list;
373 };
374 
375 typedef struct lang_address_statement_struct
376 {
377   lang_statement_header_type header;
378   const char *section_name;
379   union etree_union *address;
380   const segment_type *segment;
381 } lang_address_statement_type;
382 
383 typedef struct
384 {
385   lang_statement_header_type header;
386   bfd_vma output_offset;
387   bfd_size_type size;
388   asection *output_section;
389   fill_type *fill;
390 } lang_padding_statement_type;
391 
392 /* A group statement collects a set of libraries together.  The
393    libraries are searched multiple times, until no new undefined
394    symbols are found.  The effect is to search a group of libraries as
395    though they were a single library.  */
396 
397 typedef struct
398 {
399   lang_statement_header_type header;
400   lang_statement_list_type children;
401 } lang_group_statement_type;
402 
403 typedef struct
404 {
405   lang_statement_header_type header;
406   const char *where;
407   bfd_boolean is_before;
408 } lang_insert_statement_type;
409 
410 typedef union lang_statement_union
411 {
412   lang_statement_header_type header;
413   lang_wild_statement_type wild_statement;
414   lang_data_statement_type data_statement;
415   lang_reloc_statement_type reloc_statement;
416   lang_address_statement_type address_statement;
417   lang_output_section_statement_type output_section_statement;
418   lang_assignment_statement_type assignment_statement;
419   lang_input_statement_type input_statement;
420   lang_target_statement_type target_statement;
421   lang_output_statement_type output_statement;
422   lang_input_section_type input_section;
423   lang_common_statement_type common_statement;
424   lang_object_symbols_statement_type object_symbols_statement;
425   lang_fill_statement_type fill_statement;
426   lang_padding_statement_type padding_statement;
427   lang_group_statement_type group_statement;
428   lang_insert_statement_type insert_statement;
429 } lang_statement_union_type;
430 
431 /* This structure holds information about a program header, from the
432    PHDRS command in the linker script.  */
433 
434 struct lang_phdr
435 {
436   struct lang_phdr *next;
437   const char *name;
438   unsigned long type;
439   bfd_boolean filehdr;
440   bfd_boolean phdrs;
441   etree_type *at;
442   etree_type *flags;
443 };
444 
445 /* This structure is used to hold a list of sections which may not
446    cross reference each other.  */
447 
448 typedef struct lang_nocrossref
449 {
450   struct lang_nocrossref *next;
451   const char *name;
452 } lang_nocrossref_type;
453 
454 /* The list of nocrossref lists.  */
455 
456 struct lang_nocrossrefs
457 {
458   struct lang_nocrossrefs *next;
459   lang_nocrossref_type *list;
460 };
461 
462 /* This structure is used to hold a list of input section names which
463    will not match an output section in the linker script.  */
464 
465 struct unique_sections
466 {
467   struct unique_sections *next;
468   const char *name;
469 };
470 
471 /* This structure records symbols for which we need to keep track of
472    definedness for use in the DEFINED () test.  */
473 
474 struct lang_definedness_hash_entry
475 {
476   struct bfd_hash_entry root;
477   unsigned int by_object : 1;
478   unsigned int by_script : 1;
479   unsigned int iteration : 1;
480 };
481 
482 /* Used by place_orphan to keep track of orphan sections and statements.  */
483 
484 struct orphan_save
485 {
486   const char *name;
487   flagword flags;
488   lang_output_section_statement_type *os;
489   asection **section;
490   lang_statement_union_type **stmt;
491   lang_output_section_statement_type **os_tail;
492 };
493 
494 struct asneeded_minfo
495 {
496   struct asneeded_minfo *next;
497   const char *soname;
498   bfd *ref;
499   const char *name;
500 };
501 
502 extern struct lang_phdr *lang_phdr_list;
503 extern struct lang_nocrossrefs *nocrossref_list;
504 extern const char *output_target;
505 extern lang_output_section_statement_type *abs_output_section;
506 extern lang_statement_list_type lang_output_section_statement;
507 extern struct lang_input_statement_flags input_flags;
508 extern bfd_boolean lang_has_input_file;
509 extern lang_statement_list_type *stat_ptr;
510 extern bfd_boolean delete_output_file_on_failure;
511 
512 extern struct bfd_sym_chain entry_symbol;
513 extern const char *entry_section;
514 extern bfd_boolean entry_from_cmdline;
515 extern lang_statement_list_type file_chain;
516 extern lang_statement_list_type input_file_chain;
517 
518 extern int lang_statement_iteration;
519 extern struct asneeded_minfo **asneeded_list_tail;
520 
521 extern void (*output_bfd_hash_table_free_fn) (struct bfd_link_hash_table *);
522 
523 extern void lang_init
524   (void);
525 extern void lang_finish
526   (void);
527 extern lang_memory_region_type * lang_memory_region_lookup
528   (const char * const, bfd_boolean);
529 extern void lang_memory_region_alias
530   (const char *, const char *);
531 extern void lang_map
532   (void);
533 extern void lang_set_flags
534   (lang_memory_region_type *, const char *, int);
535 extern void lang_add_output
536   (const char *, int from_script);
537 extern lang_output_section_statement_type *lang_enter_output_section_statement
538   (const char *, etree_type *, enum section_type, etree_type *, etree_type *,
539    etree_type *, int, int);
540 extern void lang_final
541   (void);
542 extern void lang_relax_sections
543   (bfd_boolean);
544 extern void lang_process
545   (void);
546 extern void lang_section_start
547   (const char *, union etree_union *, const segment_type *);
548 extern void lang_add_entry
549   (const char *, bfd_boolean);
550 extern void lang_default_entry
551   (const char *);
552 extern void lang_add_target
553   (const char *);
554 extern void lang_add_wild
555   (struct wildcard_spec *, struct wildcard_list *, bfd_boolean);
556 extern void lang_add_map
557   (const char *);
558 extern void lang_add_fill
559   (fill_type *);
560 extern lang_assignment_statement_type *lang_add_assignment
561   (union etree_union *);
562 extern void lang_add_attribute
563   (enum statement_enum);
564 extern void lang_startup
565   (const char *);
566 extern void lang_float
567   (bfd_boolean);
568 extern void lang_leave_output_section_statement
569   (fill_type *, const char *, lang_output_section_phdr_list *,
570    const char *);
571 extern void lang_abs_symbol_at_end_of
572   (const char *, const char *);
573 extern void lang_abs_symbol_at_beginning_of
574   (const char *, const char *);
575 extern void lang_statement_append
576   (lang_statement_list_type *, lang_statement_union_type *,
577    lang_statement_union_type **);
578 extern void lang_for_each_input_file
579   (void (*dothis) (lang_input_statement_type *));
580 extern void lang_for_each_file
581   (void (*dothis) (lang_input_statement_type *));
582 extern void lang_reset_memory_regions
583   (void);
584 extern void lang_do_assignments
585   (lang_phase_type);
586 
587 #define LANG_FOR_EACH_INPUT_STATEMENT(statement)			\
588   lang_input_statement_type *statement;					\
589   for (statement = (lang_input_statement_type *) file_chain.head;	\
590        statement != (lang_input_statement_type *) NULL;			\
591        statement = (lang_input_statement_type *) statement->next)	\
592 
593 #define lang_output_section_find(NAME) \
594   lang_output_section_statement_lookup (NAME, 0, FALSE)
595 
596 extern void lang_process
597   (void);
598 extern void ldlang_add_file
599   (lang_input_statement_type *);
600 extern lang_output_section_statement_type *lang_output_section_find_by_flags
601   (const asection *, lang_output_section_statement_type **,
602    lang_match_sec_type_func);
603 extern lang_output_section_statement_type *lang_insert_orphan
604   (asection *, const char *, int, lang_output_section_statement_type *,
605    struct orphan_save *, etree_type *, lang_statement_list_type *);
606 extern lang_input_statement_type *lang_add_input_file
607   (const char *, lang_input_file_enum_type, const char *);
608 extern void lang_add_keepsyms_file
609   (const char *);
610 extern lang_output_section_statement_type *lang_output_section_get
611   (const asection *);
612 extern lang_output_section_statement_type *lang_output_section_statement_lookup
613   (const char *, int, bfd_boolean);
614 extern lang_output_section_statement_type *next_matching_output_section_statement
615   (lang_output_section_statement_type *, int);
616 extern void ldlang_add_undef
617   (const char *const, bfd_boolean);
618 extern void lang_add_output_format
619   (const char *, const char *, const char *, int);
620 extern void lang_list_init
621   (lang_statement_list_type *);
622 extern void push_stat_ptr
623   (lang_statement_list_type *);
624 extern void pop_stat_ptr
625   (void);
626 extern void lang_add_data
627   (int type, union etree_union *);
628 extern void lang_add_reloc
629   (bfd_reloc_code_real_type, reloc_howto_type *, asection *, const char *,
630    union etree_union *);
631 extern void lang_for_each_statement
632   (void (*) (lang_statement_union_type *));
633 extern void lang_for_each_statement_worker
634   (void (*) (lang_statement_union_type *), lang_statement_union_type *);
635 extern void *stat_alloc
636   (size_t);
637 extern void strip_excluded_output_sections
638   (void);
639 extern void lang_clear_os_map
640   (void);
641 extern void dprint_statement
642   (lang_statement_union_type *, int);
643 extern void lang_size_sections
644   (bfd_boolean *, bfd_boolean);
645 extern void one_lang_size_sections_pass
646   (bfd_boolean *, bfd_boolean);
647 extern void lang_add_insert
648   (const char *, int);
649 extern void lang_enter_group
650   (void);
651 extern void lang_leave_group
652   (void);
653 extern void lang_add_section
654   (lang_statement_list_type *, asection *,
655    struct flag_info *, lang_output_section_statement_type *);
656 extern void lang_new_phdr
657   (const char *, etree_type *, bfd_boolean, bfd_boolean, etree_type *,
658    etree_type *);
659 extern void lang_add_nocrossref
660   (lang_nocrossref_type *);
661 extern void lang_enter_overlay
662   (etree_type *, etree_type *);
663 extern void lang_enter_overlay_section
664   (const char *);
665 extern void lang_leave_overlay_section
666   (fill_type *, lang_output_section_phdr_list *);
667 extern void lang_leave_overlay
668   (etree_type *, int, fill_type *, const char *,
669    lang_output_section_phdr_list *, const char *);
670 
671 extern struct bfd_elf_version_expr *lang_new_vers_pattern
672   (struct bfd_elf_version_expr *, const char *, const char *, bfd_boolean);
673 extern struct bfd_elf_version_tree *lang_new_vers_node
674   (struct bfd_elf_version_expr *, struct bfd_elf_version_expr *);
675 extern struct bfd_elf_version_deps *lang_add_vers_depend
676   (struct bfd_elf_version_deps *, const char *);
677 extern void lang_register_vers_node
678   (const char *, struct bfd_elf_version_tree *, struct bfd_elf_version_deps *);
679 extern void lang_append_dynamic_list (struct bfd_elf_version_expr *);
680 extern void lang_append_dynamic_list_cpp_typeinfo (void);
681 extern void lang_append_dynamic_list_cpp_new (void);
682 extern void lang_add_unique
683   (const char *);
684 extern const char *lang_get_output_target
685   (void);
686 extern struct lang_definedness_hash_entry *lang_symbol_defined (const char *);
687 extern void lang_update_definedness
688   (const char *, struct bfd_link_hash_entry *);
689 
690 extern void add_excluded_libs (const char *);
691 extern bfd_boolean load_symbols
692   (lang_input_statement_type *, lang_statement_list_type *);
693 
694 extern bfd_boolean
695 ldlang_override_segment_assignment
696   (struct bfd_link_info *, bfd *, asection *, asection *, bfd_boolean);
697 
698 extern void
699 lang_ld_feature (char *);
700 
701 #endif
702