1 /* ldlang.h - linker command language support
2    Copyright (C) 1991-2016 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   union etree_union *origin_exp;
59   bfd_vma origin;
60   bfd_size_type length;
61   union etree_union *length_exp;
62   bfd_vma current;
63   union lang_statement_union *last_os;
64   flagword flags;
65   flagword not_flags;
66   bfd_boolean had_full_message;
67 } lang_memory_region_type;
68 
69 enum statement_enum
70 {
71   lang_output_section_statement_enum,
72   lang_assignment_statement_enum,
73   lang_input_statement_enum,
74   lang_address_statement_enum,
75   lang_wild_statement_enum,
76   lang_input_section_enum,
77   lang_object_symbols_statement_enum,
78   lang_fill_statement_enum,
79   lang_data_statement_enum,
80   lang_reloc_statement_enum,
81   lang_target_statement_enum,
82   lang_output_statement_enum,
83   lang_padding_statement_enum,
84   lang_group_statement_enum,
85   lang_insert_statement_enum,
86   lang_constructors_statement_enum
87 };
88 
89 typedef struct lang_statement_header_struct
90 {
91   union lang_statement_union *next;
92   enum statement_enum type;
93 } lang_statement_header_type;
94 
95 typedef struct
96 {
97   lang_statement_header_type header;
98   union etree_union *exp;
99 } lang_assignment_statement_type;
100 
101 typedef struct lang_target_statement_struct
102 {
103   lang_statement_header_type header;
104   const char *target;
105 } lang_target_statement_type;
106 
107 typedef struct lang_output_statement_struct
108 {
109   lang_statement_header_type header;
110   const char *name;
111 } lang_output_statement_type;
112 
113 /* Section types specified in a linker script.  */
114 
115 enum section_type
116 {
117   normal_section,
118   overlay_section,
119   noload_section,
120   noalloc_section
121 };
122 
123 /* This structure holds a list of program headers describing
124    segments in which this section should be placed.  */
125 
126 typedef struct lang_output_section_phdr_list
127 {
128   struct lang_output_section_phdr_list *next;
129   const char *name;
130   bfd_boolean used;
131 } lang_output_section_phdr_list;
132 
133 typedef struct lang_output_section_statement_struct
134 {
135   lang_statement_header_type header;
136   lang_statement_list_type children;
137   struct lang_output_section_statement_struct *next;
138   struct lang_output_section_statement_struct *prev;
139   const char *name;
140   asection *bfd_section;
141   lang_memory_region_type *region;
142   lang_memory_region_type *lma_region;
143   fill_type *fill;
144   union etree_union *addr_tree;
145   union etree_union *load_base;
146 
147   /* If non-null, an expression to evaluate after setting the section's
148      size.  The expression is evaluated inside REGION (above) with '.'
149      set to the end of the section.  Used in the last overlay section
150      to move '.' past all the overlaid sections.  */
151   union etree_union *update_dot_tree;
152 
153   lang_output_section_phdr_list *phdrs;
154 
155   unsigned int block_value;
156   int subsection_alignment;	/* Alignment of components.  */
157   int section_alignment;	/* Alignment of start of section.  */
158   int constraint;
159   flagword flags;
160   enum section_type sectype;
161   unsigned int processed_vma : 1;
162   unsigned int processed_lma : 1;
163   unsigned int all_input_readonly : 1;
164   /* If this section should be ignored.  */
165   unsigned int ignored : 1;
166   /* If this section should update "dot".  Prevents section being ignored.  */
167   unsigned int update_dot : 1;
168   /* If this section uses the alignment of its input sections.  */
169   unsigned int align_lma_with_input : 1;
170 } lang_output_section_statement_type;
171 
172 typedef struct
173 {
174   lang_statement_header_type header;
175 } lang_common_statement_type;
176 
177 typedef struct
178 {
179   lang_statement_header_type header;
180 } lang_object_symbols_statement_type;
181 
182 typedef struct
183 {
184   lang_statement_header_type header;
185   fill_type *fill;
186   int size;
187   asection *output_section;
188 } lang_fill_statement_type;
189 
190 typedef struct
191 {
192   lang_statement_header_type header;
193   unsigned int type;
194   union etree_union *exp;
195   bfd_vma value;
196   asection *output_section;
197   bfd_vma output_offset;
198 } lang_data_statement_type;
199 
200 /* Generate a reloc in the output file.  */
201 
202 typedef struct
203 {
204   lang_statement_header_type header;
205 
206   /* Reloc to generate.  */
207   bfd_reloc_code_real_type reloc;
208 
209   /* Reloc howto structure.  */
210   reloc_howto_type *howto;
211 
212   /* Section to generate reloc against.
213      Exactly one of section and name must be NULL.  */
214   asection *section;
215 
216   /* Name of symbol to generate reloc against.
217      Exactly one of section and name must be NULL.  */
218   const char *name;
219 
220   /* Expression for addend.  */
221   union etree_union *addend_exp;
222 
223   /* Resolved addend.  */
224   bfd_vma addend_value;
225 
226   /* Output section where reloc should be performed.  */
227   asection *output_section;
228 
229   /* Offset within output section.  */
230   bfd_vma output_offset;
231 } lang_reloc_statement_type;
232 
233 struct lang_input_statement_flags
234 {
235   /* 1 means this file was specified in a -l option.  */
236   unsigned int maybe_archive : 1;
237 
238   /* 1 means this file was specified in a -l:namespec option.  */
239   unsigned int full_name_provided : 1;
240 
241   /* 1 means search a set of directories for this file.  */
242   unsigned int search_dirs : 1;
243 
244   /* 1 means this was found when processing a script in the sysroot.  */
245   unsigned int sysrooted : 1;
246 
247   /* 1 means this is base file of incremental load.
248      Do not load this file's text or data.
249      Also default text_start to after this file's bss.  */
250   unsigned int just_syms : 1;
251 
252   /* Whether to search for this entry as a dynamic archive.  */
253   unsigned int dynamic : 1;
254 
255   /* Set if a DT_NEEDED tag should be added not just for the dynamic library
256      explicitly given by this entry but also for any dynamic libraries in
257      this entry's needed list.  */
258   unsigned int add_DT_NEEDED_for_dynamic : 1;
259 
260   /* Set if this entry should cause a DT_NEEDED tag only when some
261      regular file references its symbols (ie. --as-needed is in effect).  */
262   unsigned int add_DT_NEEDED_for_regular : 1;
263 
264   /* Whether to include the entire contents of an archive.  */
265   unsigned int whole_archive : 1;
266 
267   /* Set when bfd opening is successful.  */
268   unsigned int loaded : 1;
269 
270   unsigned int real : 1;
271 
272   /* Set if the file does not exist.  */
273   unsigned int missing_file : 1;
274 
275   /* Set if reloading an archive or --as-needed lib.  */
276   unsigned int reload : 1;
277 
278 #ifdef ENABLE_PLUGINS
279   /* Set if the file was claimed by a plugin.  */
280   unsigned int claimed : 1;
281 
282   /* Set if the file was claimed from an archive.  */
283   unsigned int claim_archive : 1;
284 
285   /* Set if added by the lto plugin add_input_file callback.  */
286   unsigned int lto_output : 1;
287 #endif /* ENABLE_PLUGINS */
288 
289   /* Head of list of pushed flags.  */
290   struct lang_input_statement_flags *pushed;
291 };
292 
293 typedef struct lang_input_statement_struct
294 {
295   lang_statement_header_type header;
296   /* Name of this file.  */
297   const char *filename;
298   /* Name to use for the symbol giving address of text start.
299      Usually the same as filename, but for a file spec'd with
300      -l this is the -l switch itself rather than the filename.  */
301   const char *local_sym_name;
302 
303   bfd *the_bfd;
304 
305   struct flag_info *section_flag_list;
306 
307   /* Point to the next file - whatever it is, wanders up and down
308      archives */
309   union lang_statement_union *next;
310 
311   /* Point to the next file, but skips archive contents.  */
312   union lang_statement_union *next_real_file;
313 
314   const char *target;
315 
316   struct lang_input_statement_flags flags;
317 } lang_input_statement_type;
318 
319 typedef struct
320 {
321   lang_statement_header_type header;
322   asection *section;
323 } lang_input_section_type;
324 
325 struct map_symbol_def {
326   struct bfd_link_hash_entry *entry;
327   struct map_symbol_def *next;
328 };
329 
330 /* For input sections, when writing a map file: head / tail of a linked
331    list of hash table entries for symbols defined in this section.  */
332 typedef struct input_section_userdata_struct
333 {
334   struct map_symbol_def *map_symbol_def_head;
335   struct map_symbol_def **map_symbol_def_tail;
336   unsigned long map_symbol_def_count;
337 } input_section_userdata_type;
338 
339 #define get_userdata(x) ((x)->userdata)
340 
341 
342 typedef struct lang_wild_statement_struct lang_wild_statement_type;
343 
344 typedef void (*callback_t) (lang_wild_statement_type *, struct wildcard_list *,
345 			    asection *, struct flag_info *,
346 			    lang_input_statement_type *, void *);
347 
348 typedef void (*walk_wild_section_handler_t) (lang_wild_statement_type *,
349 					     lang_input_statement_type *,
350 					     callback_t callback,
351 					     void *data);
352 
353 typedef bfd_boolean (*lang_match_sec_type_func) (bfd *, const asection *,
354 						 bfd *, const asection *);
355 
356 /* Binary search tree structure to efficiently sort sections by
357    name.  */
358 typedef struct lang_section_bst
359 {
360   asection *section;
361   struct lang_section_bst *left;
362   struct lang_section_bst *right;
363 } lang_section_bst_type;
364 
365 struct lang_wild_statement_struct
366 {
367   lang_statement_header_type header;
368   const char *filename;
369   bfd_boolean filenames_sorted;
370   struct wildcard_list *section_list;
371   bfd_boolean keep_sections;
372   lang_statement_list_type children;
373 
374   walk_wild_section_handler_t walk_wild_section_handler;
375   struct wildcard_list *handler_data[4];
376   lang_section_bst_type *tree;
377   struct flag_info *section_flag_list;
378 };
379 
380 typedef struct lang_address_statement_struct
381 {
382   lang_statement_header_type header;
383   const char *section_name;
384   union etree_union *address;
385   const segment_type *segment;
386 } lang_address_statement_type;
387 
388 typedef struct
389 {
390   lang_statement_header_type header;
391   bfd_vma output_offset;
392   bfd_size_type size;
393   asection *output_section;
394   fill_type *fill;
395 } lang_padding_statement_type;
396 
397 /* A group statement collects a set of libraries together.  The
398    libraries are searched multiple times, until no new undefined
399    symbols are found.  The effect is to search a group of libraries as
400    though they were a single library.  */
401 
402 typedef struct
403 {
404   lang_statement_header_type header;
405   lang_statement_list_type children;
406 } lang_group_statement_type;
407 
408 typedef struct
409 {
410   lang_statement_header_type header;
411   const char *where;
412   bfd_boolean is_before;
413 } lang_insert_statement_type;
414 
415 typedef union lang_statement_union
416 {
417   lang_statement_header_type header;
418   lang_wild_statement_type wild_statement;
419   lang_data_statement_type data_statement;
420   lang_reloc_statement_type reloc_statement;
421   lang_address_statement_type address_statement;
422   lang_output_section_statement_type output_section_statement;
423   lang_assignment_statement_type assignment_statement;
424   lang_input_statement_type input_statement;
425   lang_target_statement_type target_statement;
426   lang_output_statement_type output_statement;
427   lang_input_section_type input_section;
428   lang_common_statement_type common_statement;
429   lang_object_symbols_statement_type object_symbols_statement;
430   lang_fill_statement_type fill_statement;
431   lang_padding_statement_type padding_statement;
432   lang_group_statement_type group_statement;
433   lang_insert_statement_type insert_statement;
434 } lang_statement_union_type;
435 
436 /* This structure holds information about a program header, from the
437    PHDRS command in the linker script.  */
438 
439 struct lang_phdr
440 {
441   struct lang_phdr *next;
442   const char *name;
443   unsigned long type;
444   bfd_boolean filehdr;
445   bfd_boolean phdrs;
446   etree_type *at;
447   etree_type *flags;
448 };
449 
450 /* This structure is used to hold a list of sections which may not
451    cross reference each other.  */
452 
453 typedef struct lang_nocrossref
454 {
455   struct lang_nocrossref *next;
456   const char *name;
457 } lang_nocrossref_type;
458 
459 /* The list of nocrossref lists.  */
460 
461 struct lang_nocrossrefs
462 {
463   struct lang_nocrossrefs *next;
464   lang_nocrossref_type *list;
465   bfd_boolean onlyfirst;
466 };
467 
468 /* This structure is used to hold a list of input section names which
469    will not match an output section in the linker script.  */
470 
471 struct unique_sections
472 {
473   struct unique_sections *next;
474   const char *name;
475 };
476 
477 /* Used by place_orphan to keep track of orphan sections and statements.  */
478 
479 struct orphan_save
480 {
481   const char *name;
482   flagword flags;
483   lang_output_section_statement_type *os;
484   asection **section;
485   lang_statement_union_type **stmt;
486   lang_output_section_statement_type **os_tail;
487 };
488 
489 struct asneeded_minfo
490 {
491   struct asneeded_minfo *next;
492   const char *soname;
493   bfd *ref;
494   const char *name;
495 };
496 
497 extern struct lang_phdr *lang_phdr_list;
498 extern struct lang_nocrossrefs *nocrossref_list;
499 extern const char *output_target;
500 extern lang_output_section_statement_type *abs_output_section;
501 extern lang_statement_list_type lang_output_section_statement;
502 extern struct lang_input_statement_flags input_flags;
503 extern bfd_boolean lang_has_input_file;
504 extern lang_statement_list_type *stat_ptr;
505 extern bfd_boolean delete_output_file_on_failure;
506 
507 extern struct bfd_sym_chain entry_symbol;
508 extern const char *entry_section;
509 extern bfd_boolean entry_from_cmdline;
510 extern lang_statement_list_type file_chain;
511 extern lang_statement_list_type input_file_chain;
512 
513 extern int lang_statement_iteration;
514 extern struct asneeded_minfo **asneeded_list_tail;
515 
516 extern void (*output_bfd_hash_table_free_fn) (struct bfd_link_hash_table *);
517 
518 extern void lang_init
519   (void);
520 extern void lang_finish
521   (void);
522 extern lang_memory_region_type * lang_memory_region_lookup
523   (const char * const, bfd_boolean);
524 extern void lang_memory_region_alias
525   (const char *, const char *);
526 extern void lang_map
527   (void);
528 extern void lang_set_flags
529   (lang_memory_region_type *, const char *, int);
530 extern void lang_add_output
531   (const char *, int from_script);
532 extern lang_output_section_statement_type *lang_enter_output_section_statement
533   (const char *, etree_type *, enum section_type, etree_type *, etree_type *,
534    etree_type *, int, int);
535 extern void lang_final
536   (void);
537 extern void lang_relax_sections
538   (bfd_boolean);
539 extern void lang_process
540   (void);
541 extern void lang_section_start
542   (const char *, union etree_union *, const segment_type *);
543 extern void lang_add_entry
544   (const char *, bfd_boolean);
545 extern void lang_default_entry
546   (const char *);
547 extern void lang_add_target
548   (const char *);
549 extern void lang_add_wild
550   (struct wildcard_spec *, struct wildcard_list *, bfd_boolean);
551 extern void lang_add_map
552   (const char *);
553 extern void lang_add_fill
554   (fill_type *);
555 extern lang_assignment_statement_type *lang_add_assignment
556   (union etree_union *);
557 extern void lang_add_attribute
558   (enum statement_enum);
559 extern void lang_startup
560   (const char *);
561 extern void lang_float
562   (bfd_boolean);
563 extern void lang_leave_output_section_statement
564   (fill_type *, const char *, lang_output_section_phdr_list *,
565    const char *);
566 extern void lang_abs_symbol_at_end_of
567   (const char *, const char *);
568 extern void lang_abs_symbol_at_beginning_of
569   (const char *, const char *);
570 extern void lang_statement_append
571   (lang_statement_list_type *, lang_statement_union_type *,
572    lang_statement_union_type **);
573 extern void lang_for_each_input_file
574   (void (*dothis) (lang_input_statement_type *));
575 extern void lang_for_each_file
576   (void (*dothis) (lang_input_statement_type *));
577 extern void lang_reset_memory_regions
578   (void);
579 extern void lang_do_assignments
580   (lang_phase_type);
581 
582 #define LANG_FOR_EACH_INPUT_STATEMENT(statement)			\
583   lang_input_statement_type *statement;					\
584   for (statement = (lang_input_statement_type *) file_chain.head;	\
585        statement != (lang_input_statement_type *) NULL;			\
586        statement = (lang_input_statement_type *) statement->next)	\
587 
588 #define lang_output_section_find(NAME) \
589   lang_output_section_statement_lookup (NAME, 0, FALSE)
590 
591 extern void lang_process
592   (void);
593 extern void ldlang_add_file
594   (lang_input_statement_type *);
595 extern lang_output_section_statement_type *lang_output_section_find_by_flags
596   (const asection *, flagword, lang_output_section_statement_type **,
597    lang_match_sec_type_func);
598 extern lang_output_section_statement_type *lang_insert_orphan
599   (asection *, const char *, int, lang_output_section_statement_type *,
600    struct orphan_save *, etree_type *, lang_statement_list_type *);
601 extern lang_input_statement_type *lang_add_input_file
602   (const char *, lang_input_file_enum_type, const char *);
603 extern void lang_add_keepsyms_file
604   (const char *);
605 extern lang_output_section_statement_type *lang_output_section_get
606   (const asection *);
607 extern lang_output_section_statement_type *lang_output_section_statement_lookup
608   (const char *, int, bfd_boolean);
609 extern lang_output_section_statement_type *next_matching_output_section_statement
610   (lang_output_section_statement_type *, int);
611 extern void ldlang_add_undef
612   (const char *const, bfd_boolean);
613 extern void ldlang_add_require_defined
614   (const char *const);
615 extern void lang_add_output_format
616   (const char *, const char *, const char *, int);
617 extern void lang_list_init
618   (lang_statement_list_type *);
619 extern void push_stat_ptr
620   (lang_statement_list_type *);
621 extern void pop_stat_ptr
622   (void);
623 extern void lang_add_data
624   (int type, union etree_union *);
625 extern void lang_add_reloc
626   (bfd_reloc_code_real_type, reloc_howto_type *, asection *, const char *,
627    union etree_union *);
628 extern void lang_for_each_statement
629   (void (*) (lang_statement_union_type *));
630 extern void lang_for_each_statement_worker
631   (void (*) (lang_statement_union_type *), lang_statement_union_type *);
632 extern void *stat_alloc
633   (size_t);
634 extern void strip_excluded_output_sections
635   (void);
636 extern void lang_clear_os_map
637   (void);
638 extern void dprint_statement
639   (lang_statement_union_type *, int);
640 extern void lang_size_sections
641   (bfd_boolean *, bfd_boolean);
642 extern void one_lang_size_sections_pass
643   (bfd_boolean *, bfd_boolean);
644 extern void lang_add_insert
645   (const char *, int);
646 extern void lang_enter_group
647   (void);
648 extern void lang_leave_group
649   (void);
650 extern void lang_add_section
651   (lang_statement_list_type *, asection *,
652    struct flag_info *, lang_output_section_statement_type *);
653 extern void lang_new_phdr
654   (const char *, etree_type *, bfd_boolean, bfd_boolean, etree_type *,
655    etree_type *);
656 extern void lang_add_nocrossref
657   (lang_nocrossref_type *);
658 extern void lang_add_nocrossref_to
659   (lang_nocrossref_type *);
660 extern void lang_enter_overlay
661   (etree_type *, etree_type *);
662 extern void lang_enter_overlay_section
663   (const char *);
664 extern void lang_leave_overlay_section
665   (fill_type *, lang_output_section_phdr_list *);
666 extern void lang_leave_overlay
667   (etree_type *, int, fill_type *, const char *,
668    lang_output_section_phdr_list *, const char *);
669 
670 extern struct bfd_elf_version_expr *lang_new_vers_pattern
671   (struct bfd_elf_version_expr *, const char *, const char *, bfd_boolean);
672 extern struct bfd_elf_version_tree *lang_new_vers_node
673   (struct bfd_elf_version_expr *, struct bfd_elf_version_expr *);
674 extern struct bfd_elf_version_deps *lang_add_vers_depend
675   (struct bfd_elf_version_deps *, const char *);
676 extern void lang_register_vers_node
677   (const char *, struct bfd_elf_version_tree *, struct bfd_elf_version_deps *);
678 extern void lang_append_dynamic_list (struct bfd_elf_version_expr *);
679 extern void lang_append_dynamic_list_cpp_typeinfo (void);
680 extern void lang_append_dynamic_list_cpp_new (void);
681 extern void lang_add_unique
682   (const char *);
683 extern const char *lang_get_output_target
684   (void);
685 extern void add_excluded_libs (const char *);
686 extern bfd_boolean load_symbols
687   (lang_input_statement_type *, lang_statement_list_type *);
688 
689 extern bfd_boolean
690 ldlang_override_segment_assignment
691   (struct bfd_link_info *, bfd *, asection *, asection *, bfd_boolean);
692 
693 extern void
694 lang_ld_feature (char *);
695 
696 extern void
697 lang_print_memory_usage (void);
698 
699 extern void
700 lang_add_gc_name (const char *);
701 
702 #endif
703