aboutsummaryrefslogtreecommitdiff
path: root/include/plugin-api.h
blob: 6ffa4cfa26548c413ad5c23d7c0d5673968399c7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
/* plugin-api.h -- External linker plugin API.  */

/* Copyright (C) 2009-2021 Free Software Foundation, Inc.
   Written by Cary Coutant <ccoutant@google.com>.

   This file is part of binutils.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
   MA 02110-1301, USA.  */

/* This file defines the interface for writing a linker plugin, which is
   described at < http://gcc.gnu.org/wiki/whopr/driver >.  */

#ifndef PLUGIN_API_H
#define PLUGIN_API_H

#ifdef HAVE_STDINT_H
#include <stdint.h>
#elif defined(HAVE_INTTYPES_H)
#include <inttypes.h>
#endif
#include <sys/types.h>
#if !defined(HAVE_STDINT_H) && !defined(HAVE_INTTYPES_H) && \
    !defined(UINT64_MAX) && !defined(uint64_t)
#error cannot find uint64_t type
#endif

/* Detect endianess based on __BYTE_ORDER__ macro.  */
#if defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \
    defined(__ORDER_LITTLE_ENDIAN__) && defined(__ORDER_PDP_ENDIAN__)
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
#define PLUGIN_LITTLE_ENDIAN 1
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define PLUGIN_BIG_ENDIAN 1
#elif __BYTE_ORDER__ == __ORDER_PDP_ENDIAN__
#define PLUGIN_PDP_ENDIAN 1
#endif
#else
/* Older GCC releases (<4.6.0) can make detection from glibc macros.  */
#if defined(__GLIBC__) || defined(__GNU_LIBRARY__) || defined(__ANDROID__)
#include <endian.h>
#ifdef __BYTE_ORDER
#if __BYTE_ORDER == __LITTLE_ENDIAN
#define PLUGIN_LITTLE_ENDIAN 1
#elif __BYTE_ORDER == __BIG_ENDIAN
#define PLUGIN_BIG_ENDIAN 1
#endif
#endif
#endif
/* Include all necessary header files based on target.  */
#if defined(__SVR4) && defined(__sun)
#include <sys/byteorder.h>
#endif
#if defined(__FreeBSD__) || defined(__NetBSD__) || \
    defined(__DragonFly__) || defined(__minix)
#include <sys/endian.h>
#endif
#if defined(__OpenBSD__)
#include <machine/endian.h>
#endif
/* Detect endianess based on _BYTE_ORDER.  */
#ifdef _BYTE_ORDER
#if _BYTE_ORDER == _LITTLE_ENDIAN
#define PLUGIN_LITTLE_ENDIAN 1
#elif _BYTE_ORDER == _BIG_ENDIAN
#define PLUGIN_BIG_ENDIAN 1
#endif
#endif
/* Detect based on _WIN32.  */
#if defined(_WIN32)
#define PLUGIN_LITTLE_ENDIAN 1
#endif
/* Detect based on __BIG_ENDIAN__ and __LITTLE_ENDIAN__ */
#ifdef __LITTLE_ENDIAN__
#define PLUGIN_LITTLE_ENDIAN 1
#endif
#ifdef __BIG_ENDIAN__
#define PLUGIN_BIG_ENDIAN 1
#endif
#endif

#ifdef __cplusplus
extern "C"
{
#endif

/* Status code returned by most API routines.  */

enum ld_plugin_status
{
  LDPS_OK = 0,
  LDPS_NO_SYMS,         /* Attempt to get symbols that haven't been added. */
  LDPS_BAD_HANDLE,      /* No claimed object associated with given handle. */
  LDPS_ERR
  /* Additional Error codes TBD.  */
};

/* The version of the API specification.  */

enum ld_plugin_api_version
{
  LD_PLUGIN_API_VERSION = 1
};

/* The type of output file being generated by the linker.  */

enum ld_plugin_output_file_type
{
  LDPO_REL,
  LDPO_EXEC,
  LDPO_DYN,
  LDPO_PIE
};

/* An input file managed by the plugin library.  */

struct ld_plugin_input_file
{
  const char *name;
  int fd;
  off_t offset;
  off_t filesize;
  void *handle;
};

/* A symbol belonging to an input file managed by the plugin library.  */

struct ld_plugin_symbol
{
  char *name;
  char *version;
  /* This is for compatibility with older ABIs.  The older ABI defined
     only 'def' field.  */
#if PLUGIN_BIG_ENDIAN == 1
  char unused;
  char section_kind;
  char symbol_type;
  char def;
#elif PLUGIN_LITTLE_ENDIAN == 1
  char def;
  char symbol_type;
  char section_kind;
  char unused;
#elif PLUGIN_PDP_ENDIAN == 1
  char symbol_type;
  char def;
  char unused;
  char section_kind;
#else
#error "Could not detect architecture endianess"
#endif
  int visibility;
  uint64_t size;
  char *comdat_key;
  int resolution;
};

/* An object's section.  */

struct ld_plugin_section
{
  const void* handle;
  unsigned int shndx;
};

/* Whether the symbol is a definition, reference, or common, weak or not.  */

enum ld_plugin_symbol_kind
{
  LDPK_DEF,
  LDPK_WEAKDEF,
  LDPK_UNDEF,
  LDPK_WEAKUNDEF,
  LDPK_COMMON
};

/* The visibility of the symbol.  */

enum ld_plugin_symbol_visibility
{
  LDPV_DEFAULT,
  LDPV_PROTECTED,
  LDPV_INTERNAL,
  LDPV_HIDDEN
};

/* The type of the symbol.  */

enum ld_plugin_symbol_type
{
  LDST_UNKNOWN,
  LDST_FUNCTION,
  LDST_VARIABLE
};

enum ld_plugin_symbol_section_kind
{
  LDSSK_DEFAULT,
  LDSSK_BSS
};

/* How a symbol is resolved.  */

enum ld_plugin_symbol_resolution
{
  LDPR_UNKNOWN = 0,

  /* Symbol is still undefined at this point.  */
  LDPR_UNDEF,

  /* This is the prevailing definition of the symbol, with references from
     regular object code.  */
  LDPR_PREVAILING_DEF,

  /* This is the prevailing definition of the symbol, with no
     references from regular objects.  It is only referenced from IR
     code.  */
  LDPR_PREVAILING_DEF_IRONLY,

  /* This definition was pre-empted by a definition in a regular
     object file.  */
  LDPR_PREEMPTED_REG,

  /* This definition was pre-empted by a definition in another IR file.  */
  LDPR_PREEMPTED_IR,

  /* This symbol was resolved by a definition in another IR file.  */
  LDPR_RESOLVED_IR,

  /* This symbol was resolved by a definition in a regular object
     linked into the main executable.  */
  LDPR_RESOLVED_EXEC,

  /* This symbol was resolved by a definition in a shared object.  */
  LDPR_RESOLVED_DYN,

  /* This is the prevailing definition of the symbol, with no
     references from regular objects.  It is only referenced from IR
     code, but the symbol is exported and may be referenced from
     a dynamic object (not seen at link time).  */
  LDPR_PREVAILING_DEF_IRONLY_EXP
};

/* The plugin library's "claim file" handler.  */

typedef
enum ld_plugin_status
(*ld_plugin_claim_file_handler) (
  const struct ld_plugin_input_file *file, int *claimed);

/* The plugin library's "all symbols read" handler.  */

typedef
enum ld_plugin_status
(*ld_plugin_all_symbols_read_handler) (void);

/* The plugin library's cleanup handler.  */

typedef
enum ld_plugin_status
(*ld_plugin_cleanup_handler) (void);

/* The linker's interface for registering the "claim file" handler.  */

typedef
enum ld_plugin_status
(*ld_plugin_register_claim_file) (ld_plugin_claim_file_handler handler);

/* The linker's interface for registering the "all symbols read" handler.  */

typedef
enum ld_plugin_status
(*ld_plugin_register_all_symbols_read) (
  ld_plugin_all_symbols_read_handler handler);

/* The linker's interface for registering the cleanup handler.  */

typedef
enum ld_plugin_status
(*ld_plugin_register_cleanup) (ld_plugin_cleanup_handler handler);

/* The linker's interface for adding symbols from a claimed input file.  */

typedef
enum ld_plugin_status
(*ld_plugin_add_symbols) (void *handle, int nsyms,
                          const struct ld_plugin_symbol *syms);

/* The linker's interface for getting the input file information with
   an open (possibly re-opened) file descriptor.  */

typedef
enum ld_plugin_status
(*ld_plugin_get_input_file) (const void *handle,
                             struct ld_plugin_input_file *file);

typedef
enum ld_plugin_status
(*ld_plugin_get_view) (const void *handle, const void **viewp);

/* The linker's interface for releasing the input file.  */

typedef
enum ld_plugin_status
(*ld_plugin_release_input_file) (const void *handle);

/* The linker's interface for retrieving symbol resolution information.  */

typedef
enum ld_plugin_status
(*ld_plugin_get_symbols) (const void *handle, int nsyms,
                          struct ld_plugin_symbol *syms);

/* The linker's interface for adding a compiled input file.  */

typedef
enum ld_plugin_status
(*ld_plugin_add_input_file) (const char *pathname);

/* The linker's interface for adding a library that should be searched.  */

typedef
enum ld_plugin_status
(*ld_plugin_add_input_library) (const char *libname);

/* The linker's interface for adding a library path that should be searched.  */

typedef
enum ld_plugin_status
(*ld_plugin_set_extra_library_path) (const char *path);

/* The linker's interface for issuing a warning or error message.  */

typedef
enum ld_plugin_status
(*ld_plugin_message) (int level, const char *format, ...);

/* The linker's interface for retrieving the number of sections in an object.
   The handle is obtained in the claim_file handler.  This interface should
   only be invoked in the claim_file handler.   This function sets *COUNT to
   the number of sections in the object.  */

typedef
enum ld_plugin_status
(*ld_plugin_get_input_section_count) (const void* handle, unsigned int *count);

/* The linker's interface for retrieving the section type of a specific
   section in an object.  This interface should only be invoked in the
   claim_file handler.  This function sets *TYPE to an ELF SHT_xxx value.  */

typedef
enum ld_plugin_status
(*ld_plugin_get_input_section_type) (const struct ld_plugin_section section,
                                     unsigned int *type);

/* The linker's interface for retrieving the name of a specific section in
   an object. This interface should only be invoked in the claim_file handler.
   This function sets *SECTION_NAME_PTR to a null-terminated buffer allocated
   by malloc.  The plugin must free *SECTION_NAME_PTR.  */

typedef
enum ld_plugin_status
(*ld_plugin_get_input_section_name) (const struct ld_plugin_section section,
                                     char **section_name_ptr);

/* The linker's interface for retrieving the contents of a specific section
   in an object.  This interface should only be invoked in the claim_file
   handler.  This function sets *SECTION_CONTENTS to point to a buffer that is
   valid until clam_file handler returns.  It sets *LEN to the size of the
   buffer.  */

typedef
enum ld_plugin_status
(*ld_plugin_get_input_section_contents) (const struct ld_plugin_section section,
                                         const unsigned char **section_contents,
                                         size_t* len);

/* The linker's interface for specifying the desired order of sections.
   The sections should be specifed using the array SECTION_LIST in the
   order in which they should appear in the final layout.  NUM_SECTIONS
   specifies the number of entries in each array.  This should be invoked
   in the all_symbols_read handler.  */

typedef
enum ld_plugin_status
(*ld_plugin_update_section_order) (const struct ld_plugin_section *section_list,
				   unsigned int num_sections);

/* The linker's interface for specifying that reordering of sections is
   desired so that the linker can prepare for it.  This should be invoked
   before update_section_order, preferably in the claim_file handler.  */

typedef
enum ld_plugin_status
(*ld_plugin_allow_section_ordering) (void);

/* The linker's interface for specifying that a subset of sections is
   to be mapped to a unique segment.  If the plugin wants to call
   unique_segment_for_sections, it must call this function from a
   claim_file_handler or when it is first loaded.  */

typedef
enum ld_plugin_status
(*ld_plugin_allow_unique_segment_for_sections) (void);

/* The linker's interface for specifying that a specific set of sections
   must be mapped to a unique segment.  ELF segments do not have names
   and the NAME is used as the name of the newly created output section
   that is then placed in the unique PT_LOAD segment.  FLAGS is used to
   specify if any additional segment flags need to be set.  For instance,
   a specific segment flag can be set to identify this segment.  Unsetting
   segment flags that would be set by default is not possible.  The
   parameter SEGMENT_ALIGNMENT when non-zero will override the default.  */

typedef
enum ld_plugin_status
(*ld_plugin_unique_segment_for_sections) (
    const char* segment_name,
    uint64_t segment_flags,
    uint64_t segment_alignment,
    const struct ld_plugin_section * section_list,
    unsigned int num_sections);

/* The linker's interface for retrieving the section alignment requirement
   of a specific section in an object.  This interface should only be invoked in the
   claim_file handler.  This function sets *ADDRALIGN to the ELF sh_addralign
   value of the input section.  */

typedef
enum ld_plugin_status
(*ld_plugin_get_input_section_alignment) (const struct ld_plugin_section section,
                                          unsigned int *addralign);

/* The linker's interface for retrieving the section size of a specific section
   in an object.  This interface should only be invoked in the claim_file handler.
   This function sets *SECSIZE to the ELF sh_size
   value of the input section.  */

typedef
enum ld_plugin_status
(*ld_plugin_get_input_section_size) (const struct ld_plugin_section section,
                                     uint64_t *secsize);

typedef
enum ld_plugin_status
(*ld_plugin_new_input_handler) (const struct ld_plugin_input_file *file);

/* The linker's interface for registering the "new_input" handler. This handler
   will be notified when a new input file has been added after the
   all_symbols_read event, allowing the plugin to, for example, set a unique
   segment for sections in plugin-generated input files. */

typedef
enum ld_plugin_status
(*ld_plugin_register_new_input) (ld_plugin_new_input_handler handler);

/* The linker's interface for getting the list of wrapped symbols using the
   --wrap option. This sets *NUM_SYMBOLS to number of wrapped symbols and
   *WRAP_SYMBOL_LIST to the list of wrapped symbols. */

typedef
enum ld_plugin_status
(*ld_plugin_get_wrap_symbols) (uint64_t *num_symbols,
                               const char ***wrap_symbol_list);

enum ld_plugin_level
{
  LDPL_INFO,
  LDPL_WARNING,
  LDPL_ERROR,
  LDPL_FATAL
};

/* Values for the tv_tag field of the transfer vector.  */

enum ld_plugin_tag
{
  LDPT_NULL = 0,
  LDPT_API_VERSION = 1,
  LDPT_GOLD_VERSION = 2,
  LDPT_LINKER_OUTPUT = 3,
  LDPT_OPTION = 4,
  LDPT_REGISTER_CLAIM_FILE_HOOK = 5,
  LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK = 6,
  LDPT_REGISTER_CLEANUP_HOOK = 7,
  LDPT_ADD_SYMBOLS = 8,
  LDPT_GET_SYMBOLS = 9,
  LDPT_ADD_INPUT_FILE = 10,
  LDPT_MESSAGE = 11,
  LDPT_GET_INPUT_FILE = 12,
  LDPT_RELEASE_INPUT_FILE = 13,
  LDPT_ADD_INPUT_LIBRARY = 14,
  LDPT_OUTPUT_NAME = 15,
  LDPT_SET_EXTRA_LIBRARY_PATH = 16,
  LDPT_GNU_LD_VERSION = 17,
  LDPT_GET_VIEW = 18,
  LDPT_GET_INPUT_SECTION_COUNT = 19,
  LDPT_GET_INPUT_SECTION_TYPE = 20,
  LDPT_GET_INPUT_SECTION_NAME = 21,
  LDPT_GET_INPUT_SECTION_CONTENTS = 22,
  LDPT_UPDATE_SECTION_ORDER = 23,
  LDPT_ALLOW_SECTION_ORDERING = 24,
  LDPT_GET_SYMBOLS_V2 = 25,
  LDPT_ALLOW_UNIQUE_SEGMENT_FOR_SECTIONS = 26,
  LDPT_UNIQUE_SEGMENT_FOR_SECTIONS = 27,
  LDPT_GET_SYMBOLS_V3 = 28,
  LDPT_GET_INPUT_SECTION_ALIGNMENT = 29,
  LDPT_GET_INPUT_SECTION_SIZE = 30,
  LDPT_REGISTER_NEW_INPUT_HOOK = 31,
  LDPT_GET_WRAP_SYMBOLS = 32,
  LDPT_ADD_SYMBOLS_V2 = 33
};

/* The plugin transfer vector.  */

struct ld_plugin_tv
{
  enum ld_plugin_tag tv_tag;
  union
  {
    int tv_val;
    const char *tv_string;
    ld_plugin_register_claim_file tv_register_claim_file;
    ld_plugin_register_all_symbols_read tv_register_all_symbols_read;
    ld_plugin_register_cleanup tv_register_cleanup;
    ld_plugin_add_symbols tv_add_symbols;
    ld_plugin_get_symbols tv_get_symbols;
    ld_plugin_add_input_file tv_add_input_file;
    ld_plugin_message tv_message;
    ld_plugin_get_input_file tv_get_input_file;
    ld_plugin_get_view tv_get_view;
    ld_plugin_release_input_file tv_release_input_file;
    ld_plugin_add_input_library tv_add_input_library;
    ld_plugin_set_extra_library_path tv_set_extra_library_path;
    ld_plugin_get_input_section_count tv_get_input_section_count;
    ld_plugin_get_input_section_type tv_get_input_section_type;
    ld_plugin_get_input_section_name tv_get_input_section_name;
    ld_plugin_get_input_section_contents tv_get_input_section_contents;
    ld_plugin_update_section_order tv_update_section_order;
    ld_plugin_allow_section_ordering tv_allow_section_ordering;
    ld_plugin_allow_unique_segment_for_sections tv_allow_unique_segment_for_sections; 
    ld_plugin_unique_segment_for_sections tv_unique_segment_for_sections;
    ld_plugin_get_input_section_alignment tv_get_input_section_alignment;
    ld_plugin_get_input_section_size tv_get_input_section_size;
    ld_plugin_register_new_input tv_register_new_input;
    ld_plugin_get_wrap_symbols tv_get_wrap_symbols;
  } tv_u;
};

/* The plugin library's "onload" entry point.  */

typedef
enum ld_plugin_status
(*ld_plugin_onload) (struct ld_plugin_tv *tv);

#ifdef __cplusplus
}
#endif

#endif /* !defined(PLUGIN_API_H) */