Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  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
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
//===- DLL.cpp ------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines various types of chunks for the DLL import or export
// descriptor tables. They are inherently Windows-specific.
// You need to read Microsoft PE/COFF spec to understand details
// about the data structures.
//
// If you are not particularly interested in linking against Windows
// DLL, you can skip this file, and you should still be able to
// understand the rest of the linker.
//
//===----------------------------------------------------------------------===//

#include "DLL.h"
#include "Chunks.h"
#include "llvm/Object/COFF.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Path.h"

using namespace llvm;
using namespace llvm::object;
using namespace llvm::support::endian;
using namespace llvm::COFF;

namespace lld {
namespace coff {
namespace {

// Import table

// A chunk for the import descriptor table.
class HintNameChunk : public NonSectionChunk {
public:
  HintNameChunk(StringRef n, uint16_t h) : name(n), hint(h) {}

  size_t getSize() const override {
    // Starts with 2 byte Hint field, followed by a null-terminated string,
    // ends with 0 or 1 byte padding.
    return alignTo(name.size() + 3, 2);
  }

  void writeTo(uint8_t *buf) const override {
    memset(buf, 0, getSize());
    write16le(buf, hint);
    memcpy(buf + 2, name.data(), name.size());
  }

private:
  StringRef name;
  uint16_t hint;
};

// A chunk for the import descriptor table.
class LookupChunk : public NonSectionChunk {
public:
  explicit LookupChunk(Chunk *c) : hintName(c) {
    setAlignment(config->wordsize);
  }
  size_t getSize() const override { return config->wordsize; }

  void writeTo(uint8_t *buf) const override {
    if (config->is64())
      write64le(buf, hintName->getRVA());
    else
      write32le(buf, hintName->getRVA());
  }

  Chunk *hintName;
};

// A chunk for the import descriptor table.
// This chunk represent import-by-ordinal symbols.
// See Microsoft PE/COFF spec 7.1. Import Header for details.
class OrdinalOnlyChunk : public NonSectionChunk {
public:
  explicit OrdinalOnlyChunk(uint16_t v) : ordinal(v) {
    setAlignment(config->wordsize);
  }
  size_t getSize() const override { return config->wordsize; }

  void writeTo(uint8_t *buf) const override {
    // An import-by-ordinal slot has MSB 1 to indicate that
    // this is import-by-ordinal (and not import-by-name).
    if (config->is64()) {
      write64le(buf, (1ULL << 63) | ordinal);
    } else {
      write32le(buf, (1ULL << 31) | ordinal);
    }
  }

  uint16_t ordinal;
};

// A chunk for the import descriptor table.
class ImportDirectoryChunk : public NonSectionChunk {
public:
  explicit ImportDirectoryChunk(Chunk *n) : dllName(n) {}
  size_t getSize() const override { return sizeof(ImportDirectoryTableEntry); }

  void writeTo(uint8_t *buf) const override {
    memset(buf, 0, getSize());

    auto *e = (coff_import_directory_table_entry *)(buf);
    e->ImportLookupTableRVA = lookupTab->getRVA();
    e->NameRVA = dllName->getRVA();
    e->ImportAddressTableRVA = addressTab->getRVA();
  }

  Chunk *dllName;
  Chunk *lookupTab;
  Chunk *addressTab;
};

// A chunk representing null terminator in the import table.
// Contents of this chunk is always null bytes.
class NullChunk : public NonSectionChunk {
public:
  explicit NullChunk(size_t n) : size(n) { hasData = false; }
  size_t getSize() const override { return size; }

  void writeTo(uint8_t *buf) const override {
    memset(buf, 0, size);
  }

private:
  size_t size;
};

static std::vector<std::vector<DefinedImportData *>>
binImports(const std::vector<DefinedImportData *> &imports) {
  // Group DLL-imported symbols by DLL name because that's how
  // symbols are laid out in the import descriptor table.
  auto less = [](const std::string &a, const std::string &b) {
    return config->dllOrder[a] < config->dllOrder[b];
  };
  std::map<std::string, std::vector<DefinedImportData *>,
           bool(*)(const std::string &, const std::string &)> m(less);
  for (DefinedImportData *sym : imports)
    m[sym->getDLLName().lower()].push_back(sym);

  std::vector<std::vector<DefinedImportData *>> v;
  for (auto &kv : m) {
    // Sort symbols by name for each group.
    std::vector<DefinedImportData *> &syms = kv.second;
    std::sort(syms.begin(), syms.end(),
              [](DefinedImportData *a, DefinedImportData *b) {
                return a->getName() < b->getName();
              });
    v.push_back(std::move(syms));
  }
  return v;
}

// Export table
// See Microsoft PE/COFF spec 4.3 for details.

// A chunk for the delay import descriptor table etnry.
class DelayDirectoryChunk : public NonSectionChunk {
public:
  explicit DelayDirectoryChunk(Chunk *n) : dllName(n) {}

  size_t getSize() const override {
    return sizeof(delay_import_directory_table_entry);
  }

  void writeTo(uint8_t *buf) const override {
    memset(buf, 0, getSize());

    auto *e = (delay_import_directory_table_entry *)(buf);
    e->Attributes = 1;
    e->Name = dllName->getRVA();
    e->ModuleHandle = moduleHandle->getRVA();
    e->DelayImportAddressTable = addressTab->getRVA();
    e->DelayImportNameTable = nameTab->getRVA();
  }

  Chunk *dllName;
  Chunk *moduleHandle;
  Chunk *addressTab;
  Chunk *nameTab;
};

// Initial contents for delay-loaded functions.
// This code calls __delayLoadHelper2 function to resolve a symbol
// which then overwrites its jump table slot with the result
// for subsequent function calls.
static const uint8_t thunkX64[] = {
    0x48, 0x8D, 0x05, 0, 0, 0, 0,       // lea     rax, [__imp_<FUNCNAME>]
    0xE9, 0, 0, 0, 0,                   // jmp     __tailMerge_<lib>
};

static const uint8_t tailMergeX64[] = {
    0x51,                               // push    rcx
    0x52,                               // push    rdx
    0x41, 0x50,                         // push    r8
    0x41, 0x51,                         // push    r9
    0x48, 0x83, 0xEC, 0x48,             // sub     rsp, 48h
    0x66, 0x0F, 0x7F, 0x04, 0x24,       // movdqa  xmmword ptr [rsp], xmm0
    0x66, 0x0F, 0x7F, 0x4C, 0x24, 0x10, // movdqa  xmmword ptr [rsp+10h], xmm1
    0x66, 0x0F, 0x7F, 0x54, 0x24, 0x20, // movdqa  xmmword ptr [rsp+20h], xmm2
    0x66, 0x0F, 0x7F, 0x5C, 0x24, 0x30, // movdqa  xmmword ptr [rsp+30h], xmm3
    0x48, 0x8B, 0xD0,                   // mov     rdx, rax
    0x48, 0x8D, 0x0D, 0, 0, 0, 0,       // lea     rcx, [___DELAY_IMPORT_...]
    0xE8, 0, 0, 0, 0,                   // call    __delayLoadHelper2
    0x66, 0x0F, 0x6F, 0x04, 0x24,       // movdqa  xmm0, xmmword ptr [rsp]
    0x66, 0x0F, 0x6F, 0x4C, 0x24, 0x10, // movdqa  xmm1, xmmword ptr [rsp+10h]
    0x66, 0x0F, 0x6F, 0x54, 0x24, 0x20, // movdqa  xmm2, xmmword ptr [rsp+20h]
    0x66, 0x0F, 0x6F, 0x5C, 0x24, 0x30, // movdqa  xmm3, xmmword ptr [rsp+30h]
    0x48, 0x83, 0xC4, 0x48,             // add     rsp, 48h
    0x41, 0x59,                         // pop     r9
    0x41, 0x58,                         // pop     r8
    0x5A,                               // pop     rdx
    0x59,                               // pop     rcx
    0xFF, 0xE0,                         // jmp     rax
};

static const uint8_t thunkX86[] = {
    0xB8, 0, 0, 0, 0,  // mov   eax, offset ___imp__<FUNCNAME>
    0xE9, 0, 0, 0, 0,  // jmp   __tailMerge_<lib>
};

static const uint8_t tailMergeX86[] = {
    0x51,              // push  ecx
    0x52,              // push  edx
    0x50,              // push  eax
    0x68, 0, 0, 0, 0,  // push  offset ___DELAY_IMPORT_DESCRIPTOR_<DLLNAME>_dll
    0xE8, 0, 0, 0, 0,  // call  ___delayLoadHelper2@8
    0x5A,              // pop   edx
    0x59,              // pop   ecx
    0xFF, 0xE0,        // jmp   eax
};

static const uint8_t thunkARM[] = {
    0x40, 0xf2, 0x00, 0x0c, // mov.w   ip, #0 __imp_<FUNCNAME>
    0xc0, 0xf2, 0x00, 0x0c, // mov.t   ip, #0 __imp_<FUNCNAME>
    0x00, 0xf0, 0x00, 0xb8, // b.w     __tailMerge_<lib>
};

static const uint8_t tailMergeARM[] = {
    0x2d, 0xe9, 0x0f, 0x48, // push.w  {r0, r1, r2, r3, r11, lr}
    0x0d, 0xf2, 0x10, 0x0b, // addw    r11, sp, #16
    0x2d, 0xed, 0x10, 0x0b, // vpush   {d0, d1, d2, d3, d4, d5, d6, d7}
    0x61, 0x46,             // mov     r1, ip
    0x40, 0xf2, 0x00, 0x00, // mov.w   r0, #0 DELAY_IMPORT_DESCRIPTOR
    0xc0, 0xf2, 0x00, 0x00, // mov.t   r0, #0 DELAY_IMPORT_DESCRIPTOR
    0x00, 0xf0, 0x00, 0xd0, // bl      #0 __delayLoadHelper2
    0x84, 0x46,             // mov     ip, r0
    0xbd, 0xec, 0x10, 0x0b, // vpop    {d0, d1, d2, d3, d4, d5, d6, d7}
    0xbd, 0xe8, 0x0f, 0x48, // pop.w   {r0, r1, r2, r3, r11, lr}
    0x60, 0x47,             // bx      ip
};

static const uint8_t thunkARM64[] = {
    0x11, 0x00, 0x00, 0x90, // adrp    x17, #0      __imp_<FUNCNAME>
    0x31, 0x02, 0x00, 0x91, // add     x17, x17, #0 :lo12:__imp_<FUNCNAME>
    0x00, 0x00, 0x00, 0x14, // b       __tailMerge_<lib>
};

static const uint8_t tailMergeARM64[] = {
    0xfd, 0x7b, 0xb3, 0xa9, // stp     x29, x30, [sp, #-208]!
    0xfd, 0x03, 0x00, 0x91, // mov     x29, sp
    0xe0, 0x07, 0x01, 0xa9, // stp     x0, x1, [sp, #16]
    0xe2, 0x0f, 0x02, 0xa9, // stp     x2, x3, [sp, #32]
    0xe4, 0x17, 0x03, 0xa9, // stp     x4, x5, [sp, #48]
    0xe6, 0x1f, 0x04, 0xa9, // stp     x6, x7, [sp, #64]
    0xe0, 0x87, 0x02, 0xad, // stp     q0, q1, [sp, #80]
    0xe2, 0x8f, 0x03, 0xad, // stp     q2, q3, [sp, #112]
    0xe4, 0x97, 0x04, 0xad, // stp     q4, q5, [sp, #144]
    0xe6, 0x9f, 0x05, 0xad, // stp     q6, q7, [sp, #176]
    0xe1, 0x03, 0x11, 0xaa, // mov     x1, x17
    0x00, 0x00, 0x00, 0x90, // adrp    x0, #0     DELAY_IMPORT_DESCRIPTOR
    0x00, 0x00, 0x00, 0x91, // add     x0, x0, #0 :lo12:DELAY_IMPORT_DESCRIPTOR
    0x00, 0x00, 0x00, 0x94, // bl      #0 __delayLoadHelper2
    0xf0, 0x03, 0x00, 0xaa, // mov     x16, x0
    0xe6, 0x9f, 0x45, 0xad, // ldp     q6, q7, [sp, #176]
    0xe4, 0x97, 0x44, 0xad, // ldp     q4, q5, [sp, #144]
    0xe2, 0x8f, 0x43, 0xad, // ldp     q2, q3, [sp, #112]
    0xe0, 0x87, 0x42, 0xad, // ldp     q0, q1, [sp, #80]
    0xe6, 0x1f, 0x44, 0xa9, // ldp     x6, x7, [sp, #64]
    0xe4, 0x17, 0x43, 0xa9, // ldp     x4, x5, [sp, #48]
    0xe2, 0x0f, 0x42, 0xa9, // ldp     x2, x3, [sp, #32]
    0xe0, 0x07, 0x41, 0xa9, // ldp     x0, x1, [sp, #16]
    0xfd, 0x7b, 0xcd, 0xa8, // ldp     x29, x30, [sp], #208
    0x00, 0x02, 0x1f, 0xd6, // br      x16
};

// A chunk for the delay import thunk.
class ThunkChunkX64 : public NonSectionChunk {
public:
  ThunkChunkX64(Defined *i, Chunk *tm) : imp(i), tailMerge(tm) {}

  size_t getSize() const override { return sizeof(thunkX64); }

  void writeTo(uint8_t *buf) const override {
    memcpy(buf, thunkX64, sizeof(thunkX64));
    write32le(buf + 3, imp->getRVA() - rva - 7);
    write32le(buf + 8, tailMerge->getRVA() - rva - 12);
  }

  Defined *imp = nullptr;
  Chunk *tailMerge = nullptr;
};

class TailMergeChunkX64 : public NonSectionChunk {
public:
  TailMergeChunkX64(Chunk *d, Defined *h) : desc(d), helper(h) {}

  size_t getSize() const override { return sizeof(tailMergeX64); }

  void writeTo(uint8_t *buf) const override {
    memcpy(buf, tailMergeX64, sizeof(tailMergeX64));
    write32le(buf + 39, desc->getRVA() - rva - 43);
    write32le(buf + 44, helper->getRVA() - rva - 48);
  }

  Chunk *desc = nullptr;
  Defined *helper = nullptr;
};

class ThunkChunkX86 : public NonSectionChunk {
public:
  ThunkChunkX86(Defined *i, Chunk *tm) : imp(i), tailMerge(tm) {}

  size_t getSize() const override { return sizeof(thunkX86); }

  void writeTo(uint8_t *buf) const override {
    memcpy(buf, thunkX86, sizeof(thunkX86));
    write32le(buf + 1, imp->getRVA() + config->imageBase);
    write32le(buf + 6, tailMerge->getRVA() - rva - 10);
  }

  void getBaserels(std::vector<Baserel> *res) override {
    res->emplace_back(rva + 1);
  }

  Defined *imp = nullptr;
  Chunk *tailMerge = nullptr;
};

class TailMergeChunkX86 : public NonSectionChunk {
public:
  TailMergeChunkX86(Chunk *d, Defined *h) : desc(d), helper(h) {}

  size_t getSize() const override { return sizeof(tailMergeX86); }

  void writeTo(uint8_t *buf) const override {
    memcpy(buf, tailMergeX86, sizeof(tailMergeX86));
    write32le(buf + 4, desc->getRVA() + config->imageBase);
    write32le(buf + 9, helper->getRVA() - rva - 13);
  }

  void getBaserels(std::vector<Baserel> *res) override {
    res->emplace_back(rva + 4);
  }

  Chunk *desc = nullptr;
  Defined *helper = nullptr;
};

class ThunkChunkARM : public NonSectionChunk {
public:
  ThunkChunkARM(Defined *i, Chunk *tm) : imp(i), tailMerge(tm) {
    setAlignment(2);
  }

  size_t getSize() const override { return sizeof(thunkARM); }

  void writeTo(uint8_t *buf) const override {
    memcpy(buf, thunkARM, sizeof(thunkARM));
    applyMOV32T(buf + 0, imp->getRVA() + config->imageBase);
    applyBranch24T(buf + 8, tailMerge->getRVA() - rva - 12);
  }

  void getBaserels(std::vector<Baserel> *res) override {
    res->emplace_back(rva + 0, IMAGE_REL_BASED_ARM_MOV32T);
  }

  Defined *imp = nullptr;
  Chunk *tailMerge = nullptr;
};

class TailMergeChunkARM : public NonSectionChunk {
public:
  TailMergeChunkARM(Chunk *d, Defined *h) : desc(d), helper(h) {
    setAlignment(2);
  }

  size_t getSize() const override { return sizeof(tailMergeARM); }

  void writeTo(uint8_t *buf) const override {
    memcpy(buf, tailMergeARM, sizeof(tailMergeARM));
    applyMOV32T(buf + 14, desc->getRVA() + config->imageBase);
    applyBranch24T(buf + 22, helper->getRVA() - rva - 26);
  }

  void getBaserels(std::vector<Baserel> *res) override {
    res->emplace_back(rva + 14, IMAGE_REL_BASED_ARM_MOV32T);
  }

  Chunk *desc = nullptr;
  Defined *helper = nullptr;
};

class ThunkChunkARM64 : public NonSectionChunk {
public:
  ThunkChunkARM64(Defined *i, Chunk *tm) : imp(i), tailMerge(tm) {
    setAlignment(4);
  }

  size_t getSize() const override { return sizeof(thunkARM64); }

  void writeTo(uint8_t *buf) const override {
    memcpy(buf, thunkARM64, sizeof(thunkARM64));
    applyArm64Addr(buf + 0, imp->getRVA(), rva + 0, 12);
    applyArm64Imm(buf + 4, imp->getRVA() & 0xfff, 0);
    applyArm64Branch26(buf + 8, tailMerge->getRVA() - rva - 8);
  }

  Defined *imp = nullptr;
  Chunk *tailMerge = nullptr;
};

class TailMergeChunkARM64 : public NonSectionChunk {
public:
  TailMergeChunkARM64(Chunk *d, Defined *h) : desc(d), helper(h) {
    setAlignment(4);
  }

  size_t getSize() const override { return sizeof(tailMergeARM64); }

  void writeTo(uint8_t *buf) const override {
    memcpy(buf, tailMergeARM64, sizeof(tailMergeARM64));
    applyArm64Addr(buf + 44, desc->getRVA(), rva + 44, 12);
    applyArm64Imm(buf + 48, desc->getRVA() & 0xfff, 0);
    applyArm64Branch26(buf + 52, helper->getRVA() - rva - 52);
  }

  Chunk *desc = nullptr;
  Defined *helper = nullptr;
};

// A chunk for the import descriptor table.
class DelayAddressChunk : public NonSectionChunk {
public:
  explicit DelayAddressChunk(Chunk *c) : thunk(c) {
    setAlignment(config->wordsize);
  }
  size_t getSize() const override { return config->wordsize; }

  void writeTo(uint8_t *buf) const override {
    if (config->is64()) {
      write64le(buf, thunk->getRVA() + config->imageBase);
    } else {
      uint32_t bit = 0;
      // Pointer to thumb code must have the LSB set, so adjust it.
      if (config->machine == ARMNT)
        bit = 1;
      write32le(buf, (thunk->getRVA() + config->imageBase) | bit);
    }
  }

  void getBaserels(std::vector<Baserel> *res) override {
    res->emplace_back(rva);
  }

  Chunk *thunk;
};

// Export table
// Read Microsoft PE/COFF spec 5.3 for details.

// A chunk for the export descriptor table.
class ExportDirectoryChunk : public NonSectionChunk {
public:
  ExportDirectoryChunk(int i, int j, Chunk *d, Chunk *a, Chunk *n, Chunk *o)
      : maxOrdinal(i), nameTabSize(j), dllName(d), addressTab(a), nameTab(n),
        ordinalTab(o) {}

  size_t getSize() const override {
    return sizeof(export_directory_table_entry);
  }

  void writeTo(uint8_t *buf) const override {
    memset(buf, 0, getSize());

    auto *e = (export_directory_table_entry *)(buf);
    e->NameRVA = dllName->getRVA();
    e->OrdinalBase = 0;
    e->AddressTableEntries = maxOrdinal + 1;
    e->NumberOfNamePointers = nameTabSize;
    e->ExportAddressTableRVA = addressTab->getRVA();
    e->NamePointerRVA = nameTab->getRVA();
    e->OrdinalTableRVA = ordinalTab->getRVA();
  }

  uint16_t maxOrdinal;
  uint16_t nameTabSize;
  Chunk *dllName;
  Chunk *addressTab;
  Chunk *nameTab;
  Chunk *ordinalTab;
};

class AddressTableChunk : public NonSectionChunk {
public:
  explicit AddressTableChunk(size_t maxOrdinal) : size(maxOrdinal + 1) {}
  size_t getSize() const override { return size * 4; }

  void writeTo(uint8_t *buf) const override {
    memset(buf, 0, getSize());

    for (const Export &e : config->exports) {
      uint8_t *p = buf + e.ordinal * 4;
      uint32_t bit = 0;
      // Pointer to thumb code must have the LSB set, so adjust it.
      if (config->machine == ARMNT && !e.data)
        bit = 1;
      if (e.forwardChunk) {
        write32le(p, e.forwardChunk->getRVA() | bit);
      } else {
        write32le(p, cast<Defined>(e.sym)->getRVA() | bit);
      }
    }
  }

private:
  size_t size;
};

class NamePointersChunk : public NonSectionChunk {
public:
  explicit NamePointersChunk(std::vector<Chunk *> &v) : chunks(v) {}
  size_t getSize() const override { return chunks.size() * 4; }

  void writeTo(uint8_t *buf) const override {
    for (Chunk *c : chunks) {
      write32le(buf, c->getRVA());
      buf += 4;
    }
  }

private:
  std::vector<Chunk *> chunks;
};

class ExportOrdinalChunk : public NonSectionChunk {
public:
  explicit ExportOrdinalChunk(size_t i) : size(i) {}
  size_t getSize() const override { return size * 2; }

  void writeTo(uint8_t *buf) const override {
    for (Export &e : config->exports) {
      if (e.noname)
        continue;
      write16le(buf, e.ordinal);
      buf += 2;
    }
  }

private:
  size_t size;
};

} // anonymous namespace

void IdataContents::create() {
  std::vector<std::vector<DefinedImportData *>> v = binImports(imports);

  // Create .idata contents for each DLL.
  for (std::vector<DefinedImportData *> &syms : v) {
    // Create lookup and address tables. If they have external names,
    // we need to create hintName chunks to store the names.
    // If they don't (if they are import-by-ordinals), we store only
    // ordinal values to the table.
    size_t base = lookups.size();
    for (DefinedImportData *s : syms) {
      uint16_t ord = s->getOrdinal();
      if (s->getExternalName().empty()) {
        lookups.push_back(make<OrdinalOnlyChunk>(ord));
        addresses.push_back(make<OrdinalOnlyChunk>(ord));
        continue;
      }
      auto *c = make<HintNameChunk>(s->getExternalName(), ord);
      lookups.push_back(make<LookupChunk>(c));
      addresses.push_back(make<LookupChunk>(c));
      hints.push_back(c);
    }
    // Terminate with null values.
    lookups.push_back(make<NullChunk>(config->wordsize));
    addresses.push_back(make<NullChunk>(config->wordsize));

    for (int i = 0, e = syms.size(); i < e; ++i)
      syms[i]->setLocation(addresses[base + i]);

    // Create the import table header.
    dllNames.push_back(make<StringChunk>(syms[0]->getDLLName()));
    auto *dir = make<ImportDirectoryChunk>(dllNames.back());
    dir->lookupTab = lookups[base];
    dir->addressTab = addresses[base];
    dirs.push_back(dir);
  }
  // Add null terminator.
  dirs.push_back(make<NullChunk>(sizeof(ImportDirectoryTableEntry)));
}

std::vector<Chunk *> DelayLoadContents::getChunks() {
  std::vector<Chunk *> v;
  v.insert(v.end(), dirs.begin(), dirs.end());
  v.insert(v.end(), names.begin(), names.end());
  v.insert(v.end(), hintNames.begin(), hintNames.end());
  v.insert(v.end(), dllNames.begin(), dllNames.end());
  return v;
}

std::vector<Chunk *> DelayLoadContents::getDataChunks() {
  std::vector<Chunk *> v;
  v.insert(v.end(), moduleHandles.begin(), moduleHandles.end());
  v.insert(v.end(), addresses.begin(), addresses.end());
  return v;
}

uint64_t DelayLoadContents::getDirSize() {
  return dirs.size() * sizeof(delay_import_directory_table_entry);
}

void DelayLoadContents::create(Defined *h) {
  helper = h;
  std::vector<std::vector<DefinedImportData *>> v = binImports(imports);

  // Create .didat contents for each DLL.
  for (std::vector<DefinedImportData *> &syms : v) {
    // Create the delay import table header.
    dllNames.push_back(make<StringChunk>(syms[0]->getDLLName()));
    auto *dir = make<DelayDirectoryChunk>(dllNames.back());

    size_t base = addresses.size();
    Chunk *tm = newTailMergeChunk(dir);
    for (DefinedImportData *s : syms) {
      Chunk *t = newThunkChunk(s, tm);
      auto *a = make<DelayAddressChunk>(t);
      addresses.push_back(a);
      thunks.push_back(t);
      StringRef extName = s->getExternalName();
      if (extName.empty()) {
        names.push_back(make<OrdinalOnlyChunk>(s->getOrdinal()));
      } else {
        auto *c = make<HintNameChunk>(extName, 0);
        names.push_back(make<LookupChunk>(c));
        hintNames.push_back(c);
      }
    }
    thunks.push_back(tm);
    // Terminate with null values.
    addresses.push_back(make<NullChunk>(8));
    names.push_back(make<NullChunk>(8));

    for (int i = 0, e = syms.size(); i < e; ++i)
      syms[i]->setLocation(addresses[base + i]);
    auto *mh = make<NullChunk>(8);
    mh->setAlignment(8);
    moduleHandles.push_back(mh);

    // Fill the delay import table header fields.
    dir->moduleHandle = mh;
    dir->addressTab = addresses[base];
    dir->nameTab = names[base];
    dirs.push_back(dir);
  }
  // Add null terminator.
  dirs.push_back(make<NullChunk>(sizeof(delay_import_directory_table_entry)));
}

Chunk *DelayLoadContents::newTailMergeChunk(Chunk *dir) {
  switch (config->machine) {
  case AMD64:
    return make<TailMergeChunkX64>(dir, helper);
  case I386:
    return make<TailMergeChunkX86>(dir, helper);
  case ARMNT:
    return make<TailMergeChunkARM>(dir, helper);
  case ARM64:
    return make<TailMergeChunkARM64>(dir, helper);
  default:
    llvm_unreachable("unsupported machine type");
  }
}

Chunk *DelayLoadContents::newThunkChunk(DefinedImportData *s,
                                        Chunk *tailMerge) {
  switch (config->machine) {
  case AMD64:
    return make<ThunkChunkX64>(s, tailMerge);
  case I386:
    return make<ThunkChunkX86>(s, tailMerge);
  case ARMNT:
    return make<ThunkChunkARM>(s, tailMerge);
  case ARM64:
    return make<ThunkChunkARM64>(s, tailMerge);
  default:
    llvm_unreachable("unsupported machine type");
  }
}

EdataContents::EdataContents() {
  uint16_t maxOrdinal = 0;
  for (Export &e : config->exports)
    maxOrdinal = std::max(maxOrdinal, e.ordinal);

  auto *dllName = make<StringChunk>(sys::path::filename(config->outputFile));
  auto *addressTab = make<AddressTableChunk>(maxOrdinal);
  std::vector<Chunk *> names;
  for (Export &e : config->exports)
    if (!e.noname)
      names.push_back(make<StringChunk>(e.exportName));

  std::vector<Chunk *> forwards;
  for (Export &e : config->exports) {
    if (e.forwardTo.empty())
      continue;
    e.forwardChunk = make<StringChunk>(e.forwardTo);
    forwards.push_back(e.forwardChunk);
  }

  auto *nameTab = make<NamePointersChunk>(names);
  auto *ordinalTab = make<ExportOrdinalChunk>(names.size());
  auto *dir = make<ExportDirectoryChunk>(maxOrdinal, names.size(), dllName,
                                         addressTab, nameTab, ordinalTab);
  chunks.push_back(dir);
  chunks.push_back(dllName);
  chunks.push_back(addressTab);
  chunks.push_back(nameTab);
  chunks.push_back(ordinalTab);
  chunks.insert(chunks.end(), names.begin(), names.end());
  chunks.insert(chunks.end(), forwards.begin(), forwards.end());
}

} // namespace coff
} // namespace lld