1//===- DLL.cpp ------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines various types of chunks for the DLL import or export
10// descriptor tables. They are inherently Windows-specific.
11// You need to read Microsoft PE/COFF spec to understand details
12// about the data structures.
13//
14// If you are not particularly interested in linking against Windows
15// DLL, you can skip this file, and you should still be able to
16// understand the rest of the linker.
17//
18//===----------------------------------------------------------------------===//
19
20#include "DLL.h"
21#include "COFFLinkerContext.h"
22#include "Chunks.h"
23#include "SymbolTable.h"
24#include "llvm/ADT/STLExtras.h"
25#include "llvm/Object/COFF.h"
26#include "llvm/Support/Endian.h"
27#include "llvm/Support/Path.h"
28
29using namespace llvm;
30using namespace llvm::object;
31using namespace llvm::support::endian;
32using namespace llvm::COFF;
33
34namespace lld::coff {
35namespace {
36
37// Import table
38
39// A chunk for the import descriptor table.
40class HintNameChunk : public NonSectionChunk {
41public:
42 HintNameChunk(StringRef n, uint16_t h) : name(n), hint(h) {}
43
44 size_t getSize() const override {
45 // Starts with 2 byte Hint field, followed by a null-terminated string,
46 // ends with 0 or 1 byte padding.
47 return alignTo(Value: name.size() + 3, Align: 2);
48 }
49
50 void writeTo(uint8_t *buf) const override {
51 memset(s: buf, c: 0, n: getSize());
52 write16le(P: buf, V: hint);
53 memcpy(dest: buf + 2, src: name.data(), n: name.size());
54 }
55
56private:
57 StringRef name;
58 uint16_t hint;
59};
60
61// A chunk for the import descriptor table.
62class LookupChunk : public NonSectionChunk {
63public:
64 explicit LookupChunk(COFFLinkerContext &ctx, Chunk *c)
65 : hintName(c), ctx(ctx) {
66 setAlignment(ctx.config.wordsize);
67 }
68 size_t getSize() const override { return ctx.config.wordsize; }
69
70 void writeTo(uint8_t *buf) const override {
71 if (ctx.config.is64())
72 write64le(P: buf, V: hintName->getRVA());
73 else
74 write32le(P: buf, V: hintName->getRVA());
75 }
76
77 Chunk *hintName;
78
79private:
80 COFFLinkerContext &ctx;
81};
82
83// A chunk for the import descriptor table.
84// This chunk represent import-by-ordinal symbols.
85// See Microsoft PE/COFF spec 7.1. Import Header for details.
86class OrdinalOnlyChunk : public NonSectionChunk {
87public:
88 explicit OrdinalOnlyChunk(COFFLinkerContext &c, uint16_t v)
89 : ordinal(v), ctx(c) {
90 setAlignment(ctx.config.wordsize);
91 }
92 size_t getSize() const override { return ctx.config.wordsize; }
93
94 void writeTo(uint8_t *buf) const override {
95 // An import-by-ordinal slot has MSB 1 to indicate that
96 // this is import-by-ordinal (and not import-by-name).
97 if (ctx.config.is64()) {
98 write64le(P: buf, V: (1ULL << 63) | ordinal);
99 } else {
100 write32le(P: buf, V: (1ULL << 31) | ordinal);
101 }
102 }
103
104 uint16_t ordinal;
105
106private:
107 COFFLinkerContext &ctx;
108};
109
110// A chunk for the import descriptor table.
111class ImportDirectoryChunk : public NonSectionChunk {
112public:
113 explicit ImportDirectoryChunk(Chunk *n) : dllName(n) { setAlignment(4); }
114 size_t getSize() const override { return sizeof(ImportDirectoryTableEntry); }
115
116 void writeTo(uint8_t *buf) const override {
117 memset(s: buf, c: 0, n: getSize());
118
119 auto *e = (coff_import_directory_table_entry *)(buf);
120 e->ImportLookupTableRVA = lookupTab->getRVA();
121 e->NameRVA = dllName->getRVA();
122 e->ImportAddressTableRVA = addressTab->getRVA();
123 }
124
125 Chunk *dllName;
126 Chunk *lookupTab;
127 Chunk *addressTab;
128};
129
130// A chunk representing null terminator in the import table.
131// Contents of this chunk is always null bytes.
132class NullChunk : public NonSectionChunk {
133public:
134 explicit NullChunk(size_t n) : size(n) { hasData = false; }
135 size_t getSize() const override { return size; }
136
137 void writeTo(uint8_t *buf) const override {
138 memset(s: buf, c: 0, n: size);
139 }
140
141private:
142 size_t size;
143};
144
145static std::vector<std::vector<DefinedImportData *>>
146binImports(COFFLinkerContext &ctx,
147 const std::vector<DefinedImportData *> &imports) {
148 // Group DLL-imported symbols by DLL name because that's how
149 // symbols are laid out in the import descriptor table.
150 auto less = [&ctx](const std::string &a, const std::string &b) {
151 return ctx.config.dllOrder[a] < ctx.config.dllOrder[b];
152 };
153 std::map<std::string, std::vector<DefinedImportData *>, decltype(less)> m(
154 less);
155 for (DefinedImportData *sym : imports)
156 m[sym->getDLLName().lower()].push_back(x: sym);
157
158 std::vector<std::vector<DefinedImportData *>> v;
159 for (auto &kv : m) {
160 // Sort symbols by name for each group.
161 std::vector<DefinedImportData *> &syms = kv.second;
162 llvm::sort(C&: syms, Comp: [](DefinedImportData *a, DefinedImportData *b) {
163 return a->getName() < b->getName();
164 });
165 v.push_back(x: std::move(syms));
166 }
167 return v;
168}
169
170// See Microsoft PE/COFF spec 4.3 for details.
171
172// A chunk for the delay import descriptor table etnry.
173class DelayDirectoryChunk : public NonSectionChunk {
174public:
175 explicit DelayDirectoryChunk(Chunk *n) : dllName(n) { setAlignment(4); }
176
177 size_t getSize() const override {
178 return sizeof(delay_import_directory_table_entry);
179 }
180
181 void writeTo(uint8_t *buf) const override {
182 memset(s: buf, c: 0, n: getSize());
183
184 auto *e = (delay_import_directory_table_entry *)(buf);
185 e->Attributes = 1;
186 e->Name = dllName->getRVA();
187 e->ModuleHandle = moduleHandle->getRVA();
188 e->DelayImportAddressTable = addressTab->getRVA();
189 e->DelayImportNameTable = nameTab->getRVA();
190 }
191
192 Chunk *dllName;
193 Chunk *moduleHandle;
194 Chunk *addressTab;
195 Chunk *nameTab;
196};
197
198// Initial contents for delay-loaded functions.
199// This code calls __delayLoadHelper2 function to resolve a symbol
200// which then overwrites its jump table slot with the result
201// for subsequent function calls.
202static const uint8_t thunkX64[] = {
203 0x48, 0x8D, 0x05, 0, 0, 0, 0, // lea rax, [__imp_<FUNCNAME>]
204 0xE9, 0, 0, 0, 0, // jmp __tailMerge_<lib>
205};
206
207static const uint8_t tailMergeX64[] = {
208 0x51, // push rcx
209 0x52, // push rdx
210 0x41, 0x50, // push r8
211 0x41, 0x51, // push r9
212 0x48, 0x83, 0xEC, 0x48, // sub rsp, 48h
213 0x66, 0x0F, 0x7F, 0x04, 0x24, // movdqa xmmword ptr [rsp], xmm0
214 0x66, 0x0F, 0x7F, 0x4C, 0x24, 0x10, // movdqa xmmword ptr [rsp+10h], xmm1
215 0x66, 0x0F, 0x7F, 0x54, 0x24, 0x20, // movdqa xmmword ptr [rsp+20h], xmm2
216 0x66, 0x0F, 0x7F, 0x5C, 0x24, 0x30, // movdqa xmmword ptr [rsp+30h], xmm3
217 0x48, 0x8B, 0xD0, // mov rdx, rax
218 0x48, 0x8D, 0x0D, 0, 0, 0, 0, // lea rcx, [___DELAY_IMPORT_...]
219 0xE8, 0, 0, 0, 0, // call __delayLoadHelper2
220 0x66, 0x0F, 0x6F, 0x04, 0x24, // movdqa xmm0, xmmword ptr [rsp]
221 0x66, 0x0F, 0x6F, 0x4C, 0x24, 0x10, // movdqa xmm1, xmmword ptr [rsp+10h]
222 0x66, 0x0F, 0x6F, 0x54, 0x24, 0x20, // movdqa xmm2, xmmword ptr [rsp+20h]
223 0x66, 0x0F, 0x6F, 0x5C, 0x24, 0x30, // movdqa xmm3, xmmword ptr [rsp+30h]
224 0x48, 0x83, 0xC4, 0x48, // add rsp, 48h
225 0x41, 0x59, // pop r9
226 0x41, 0x58, // pop r8
227 0x5A, // pop rdx
228 0x59, // pop rcx
229 0xFF, 0xE0, // jmp rax
230};
231
232static const uint8_t tailMergeUnwindInfoX64[] = {
233 0x01, // Version=1, Flags=UNW_FLAG_NHANDLER
234 0x0a, // Size of prolog
235 0x05, // Count of unwind codes
236 0x00, // No frame register
237 0x0a, 0x82, // Offset 0xa: UWOP_ALLOC_SMALL(0x48)
238 0x06, 0x02, // Offset 6: UWOP_ALLOC_SMALL(8)
239 0x04, 0x02, // Offset 4: UWOP_ALLOC_SMALL(8)
240 0x02, 0x02, // Offset 2: UWOP_ALLOC_SMALL(8)
241 0x01, 0x02, // Offset 1: UWOP_ALLOC_SMALL(8)
242 0x00, 0x00 // Padding to align on 32-bits
243};
244
245static const uint8_t thunkX86[] = {
246 0xB8, 0, 0, 0, 0, // mov eax, offset ___imp__<FUNCNAME>
247 0xE9, 0, 0, 0, 0, // jmp __tailMerge_<lib>
248};
249
250static const uint8_t tailMergeX86[] = {
251 0x51, // push ecx
252 0x52, // push edx
253 0x50, // push eax
254 0x68, 0, 0, 0, 0, // push offset ___DELAY_IMPORT_DESCRIPTOR_<DLLNAME>_dll
255 0xE8, 0, 0, 0, 0, // call ___delayLoadHelper2@8
256 0x5A, // pop edx
257 0x59, // pop ecx
258 0xFF, 0xE0, // jmp eax
259};
260
261static const uint8_t thunkARM[] = {
262 0x40, 0xf2, 0x00, 0x0c, // mov.w ip, #0 __imp_<FUNCNAME>
263 0xc0, 0xf2, 0x00, 0x0c, // mov.t ip, #0 __imp_<FUNCNAME>
264 0x00, 0xf0, 0x00, 0xb8, // b.w __tailMerge_<lib>
265};
266
267static const uint8_t tailMergeARM[] = {
268 0x2d, 0xe9, 0x0f, 0x48, // push.w {r0, r1, r2, r3, r11, lr}
269 0x0d, 0xf2, 0x10, 0x0b, // addw r11, sp, #16
270 0x2d, 0xed, 0x10, 0x0b, // vpush {d0, d1, d2, d3, d4, d5, d6, d7}
271 0x61, 0x46, // mov r1, ip
272 0x40, 0xf2, 0x00, 0x00, // mov.w r0, #0 DELAY_IMPORT_DESCRIPTOR
273 0xc0, 0xf2, 0x00, 0x00, // mov.t r0, #0 DELAY_IMPORT_DESCRIPTOR
274 0x00, 0xf0, 0x00, 0xd0, // bl #0 __delayLoadHelper2
275 0x84, 0x46, // mov ip, r0
276 0xbd, 0xec, 0x10, 0x0b, // vpop {d0, d1, d2, d3, d4, d5, d6, d7}
277 0xbd, 0xe8, 0x0f, 0x48, // pop.w {r0, r1, r2, r3, r11, lr}
278 0x60, 0x47, // bx ip
279};
280
281static const uint8_t thunkARM64[] = {
282 0x11, 0x00, 0x00, 0x90, // adrp x17, #0 __imp_<FUNCNAME>
283 0x31, 0x02, 0x00, 0x91, // add x17, x17, #0 :lo12:__imp_<FUNCNAME>
284 0x00, 0x00, 0x00, 0x14, // b __tailMerge_<lib>
285};
286
287static const uint8_t tailMergeARM64[] = {
288 0xfd, 0x7b, 0xb3, 0xa9, // stp x29, x30, [sp, #-208]!
289 0xfd, 0x03, 0x00, 0x91, // mov x29, sp
290 0xe0, 0x07, 0x01, 0xa9, // stp x0, x1, [sp, #16]
291 0xe2, 0x0f, 0x02, 0xa9, // stp x2, x3, [sp, #32]
292 0xe4, 0x17, 0x03, 0xa9, // stp x4, x5, [sp, #48]
293 0xe6, 0x1f, 0x04, 0xa9, // stp x6, x7, [sp, #64]
294 0xe0, 0x87, 0x02, 0xad, // stp q0, q1, [sp, #80]
295 0xe2, 0x8f, 0x03, 0xad, // stp q2, q3, [sp, #112]
296 0xe4, 0x97, 0x04, 0xad, // stp q4, q5, [sp, #144]
297 0xe6, 0x9f, 0x05, 0xad, // stp q6, q7, [sp, #176]
298 0xe1, 0x03, 0x11, 0xaa, // mov x1, x17
299 0x00, 0x00, 0x00, 0x90, // adrp x0, #0 DELAY_IMPORT_DESCRIPTOR
300 0x00, 0x00, 0x00, 0x91, // add x0, x0, #0 :lo12:DELAY_IMPORT_DESCRIPTOR
301 0x00, 0x00, 0x00, 0x94, // bl #0 __delayLoadHelper2
302 0xf0, 0x03, 0x00, 0xaa, // mov x16, x0
303 0xe6, 0x9f, 0x45, 0xad, // ldp q6, q7, [sp, #176]
304 0xe4, 0x97, 0x44, 0xad, // ldp q4, q5, [sp, #144]
305 0xe2, 0x8f, 0x43, 0xad, // ldp q2, q3, [sp, #112]
306 0xe0, 0x87, 0x42, 0xad, // ldp q0, q1, [sp, #80]
307 0xe6, 0x1f, 0x44, 0xa9, // ldp x6, x7, [sp, #64]
308 0xe4, 0x17, 0x43, 0xa9, // ldp x4, x5, [sp, #48]
309 0xe2, 0x0f, 0x42, 0xa9, // ldp x2, x3, [sp, #32]
310 0xe0, 0x07, 0x41, 0xa9, // ldp x0, x1, [sp, #16]
311 0xfd, 0x7b, 0xcd, 0xa8, // ldp x29, x30, [sp], #208
312 0x00, 0x02, 0x1f, 0xd6, // br x16
313};
314
315// A chunk for the delay import thunk.
316class ThunkChunkX64 : public NonSectionCodeChunk {
317public:
318 ThunkChunkX64(Defined *i, Chunk *tm) : imp(i), tailMerge(tm) {}
319
320 size_t getSize() const override { return sizeof(thunkX64); }
321 MachineTypes getMachine() const override { return AMD64; }
322
323 void writeTo(uint8_t *buf) const override {
324 memcpy(dest: buf, src: thunkX64, n: sizeof(thunkX64));
325 write32le(P: buf + 3, V: imp->getRVA() - rva - 7);
326 write32le(P: buf + 8, V: tailMerge->getRVA() - rva - 12);
327 }
328
329 Defined *imp = nullptr;
330 Chunk *tailMerge = nullptr;
331};
332
333class TailMergeChunkX64 : public NonSectionCodeChunk {
334public:
335 TailMergeChunkX64(Chunk *d, Defined *h) : desc(d), helper(h) {}
336
337 size_t getSize() const override { return sizeof(tailMergeX64); }
338 MachineTypes getMachine() const override { return AMD64; }
339
340 void writeTo(uint8_t *buf) const override {
341 memcpy(dest: buf, src: tailMergeX64, n: sizeof(tailMergeX64));
342 write32le(P: buf + 39, V: desc->getRVA() - rva - 43);
343 write32le(P: buf + 44, V: helper->getRVA() - rva - 48);
344 }
345
346 Chunk *desc = nullptr;
347 Defined *helper = nullptr;
348};
349
350class TailMergePDataChunkX64 : public NonSectionChunk {
351public:
352 TailMergePDataChunkX64(Chunk *tm, Chunk *unwind) : tm(tm), unwind(unwind) {
353 // See
354 // https://learn.microsoft.com/en-us/cpp/build/exception-handling-x64#struct-runtime_function
355 setAlignment(4);
356 }
357
358 size_t getSize() const override { return 3 * sizeof(uint32_t); }
359
360 void writeTo(uint8_t *buf) const override {
361 write32le(P: buf + 0, V: tm->getRVA()); // TailMergeChunk start RVA
362 write32le(P: buf + 4, V: tm->getRVA() + tm->getSize()); // TailMergeChunk stop RVA
363 write32le(P: buf + 8, V: unwind->getRVA()); // UnwindInfo RVA
364 }
365
366 Chunk *tm = nullptr;
367 Chunk *unwind = nullptr;
368};
369
370class TailMergeUnwindInfoX64 : public NonSectionChunk {
371public:
372 TailMergeUnwindInfoX64() {
373 // See
374 // https://learn.microsoft.com/en-us/cpp/build/exception-handling-x64#struct-unwind_info
375 setAlignment(4);
376 }
377
378 size_t getSize() const override { return sizeof(tailMergeUnwindInfoX64); }
379
380 void writeTo(uint8_t *buf) const override {
381 memcpy(dest: buf, src: tailMergeUnwindInfoX64, n: sizeof(tailMergeUnwindInfoX64));
382 }
383};
384
385class ThunkChunkX86 : public NonSectionCodeChunk {
386public:
387 ThunkChunkX86(COFFLinkerContext &ctx, Defined *i, Chunk *tm)
388 : imp(i), tailMerge(tm), ctx(ctx) {}
389
390 size_t getSize() const override { return sizeof(thunkX86); }
391 MachineTypes getMachine() const override { return I386; }
392
393 void writeTo(uint8_t *buf) const override {
394 memcpy(dest: buf, src: thunkX86, n: sizeof(thunkX86));
395 write32le(P: buf + 1, V: imp->getRVA() + ctx.config.imageBase);
396 write32le(P: buf + 6, V: tailMerge->getRVA() - rva - 10);
397 }
398
399 void getBaserels(std::vector<Baserel> *res) override {
400 res->emplace_back(args: rva + 1, args: ctx.config.machine);
401 }
402
403 Defined *imp = nullptr;
404 Chunk *tailMerge = nullptr;
405
406private:
407 const COFFLinkerContext &ctx;
408};
409
410class TailMergeChunkX86 : public NonSectionCodeChunk {
411public:
412 TailMergeChunkX86(COFFLinkerContext &ctx, Chunk *d, Defined *h)
413 : desc(d), helper(h), ctx(ctx) {}
414
415 size_t getSize() const override { return sizeof(tailMergeX86); }
416 MachineTypes getMachine() const override { return I386; }
417
418 void writeTo(uint8_t *buf) const override {
419 memcpy(dest: buf, src: tailMergeX86, n: sizeof(tailMergeX86));
420 write32le(P: buf + 4, V: desc->getRVA() + ctx.config.imageBase);
421 write32le(P: buf + 9, V: helper->getRVA() - rva - 13);
422 }
423
424 void getBaserels(std::vector<Baserel> *res) override {
425 res->emplace_back(args: rva + 4, args: ctx.config.machine);
426 }
427
428 Chunk *desc = nullptr;
429 Defined *helper = nullptr;
430
431private:
432 const COFFLinkerContext &ctx;
433};
434
435class ThunkChunkARM : public NonSectionCodeChunk {
436public:
437 ThunkChunkARM(COFFLinkerContext &ctx, Defined *i, Chunk *tm)
438 : imp(i), tailMerge(tm), ctx(ctx) {
439 setAlignment(2);
440 }
441
442 size_t getSize() const override { return sizeof(thunkARM); }
443 MachineTypes getMachine() const override { return ARMNT; }
444
445 void writeTo(uint8_t *buf) const override {
446 memcpy(dest: buf, src: thunkARM, n: sizeof(thunkARM));
447 applyMOV32T(off: buf + 0, v: imp->getRVA() + ctx.config.imageBase);
448 applyBranch24T(off: buf + 8, v: tailMerge->getRVA() - rva - 12);
449 }
450
451 void getBaserels(std::vector<Baserel> *res) override {
452 res->emplace_back(args: rva + 0, args: IMAGE_REL_BASED_ARM_MOV32T);
453 }
454
455 Defined *imp = nullptr;
456 Chunk *tailMerge = nullptr;
457
458private:
459 const COFFLinkerContext &ctx;
460};
461
462class TailMergeChunkARM : public NonSectionCodeChunk {
463public:
464 TailMergeChunkARM(COFFLinkerContext &ctx, Chunk *d, Defined *h)
465 : desc(d), helper(h), ctx(ctx) {
466 setAlignment(2);
467 }
468
469 size_t getSize() const override { return sizeof(tailMergeARM); }
470 MachineTypes getMachine() const override { return ARMNT; }
471
472 void writeTo(uint8_t *buf) const override {
473 memcpy(dest: buf, src: tailMergeARM, n: sizeof(tailMergeARM));
474 applyMOV32T(off: buf + 14, v: desc->getRVA() + ctx.config.imageBase);
475 applyBranch24T(off: buf + 22, v: helper->getRVA() - rva - 26);
476 }
477
478 void getBaserels(std::vector<Baserel> *res) override {
479 res->emplace_back(args: rva + 14, args: IMAGE_REL_BASED_ARM_MOV32T);
480 }
481
482 Chunk *desc = nullptr;
483 Defined *helper = nullptr;
484
485private:
486 const COFFLinkerContext &ctx;
487};
488
489class ThunkChunkARM64 : public NonSectionCodeChunk {
490public:
491 ThunkChunkARM64(Defined *i, Chunk *tm) : imp(i), tailMerge(tm) {
492 setAlignment(4);
493 }
494
495 size_t getSize() const override { return sizeof(thunkARM64); }
496 MachineTypes getMachine() const override { return ARM64; }
497
498 void writeTo(uint8_t *buf) const override {
499 memcpy(dest: buf, src: thunkARM64, n: sizeof(thunkARM64));
500 applyArm64Addr(off: buf + 0, s: imp->getRVA(), p: rva + 0, shift: 12);
501 applyArm64Imm(off: buf + 4, imm: imp->getRVA() & 0xfff, rangeLimit: 0);
502 applyArm64Branch26(off: buf + 8, v: tailMerge->getRVA() - rva - 8);
503 }
504
505 Defined *imp = nullptr;
506 Chunk *tailMerge = nullptr;
507};
508
509class TailMergeChunkARM64 : public NonSectionCodeChunk {
510public:
511 TailMergeChunkARM64(Chunk *d, Defined *h) : desc(d), helper(h) {
512 setAlignment(4);
513 }
514
515 size_t getSize() const override { return sizeof(tailMergeARM64); }
516 MachineTypes getMachine() const override { return ARM64; }
517
518 void writeTo(uint8_t *buf) const override {
519 memcpy(dest: buf, src: tailMergeARM64, n: sizeof(tailMergeARM64));
520 applyArm64Addr(off: buf + 44, s: desc->getRVA(), p: rva + 44, shift: 12);
521 applyArm64Imm(off: buf + 48, imm: desc->getRVA() & 0xfff, rangeLimit: 0);
522 applyArm64Branch26(off: buf + 52, v: helper->getRVA() - rva - 52);
523 }
524
525 Chunk *desc = nullptr;
526 Defined *helper = nullptr;
527};
528
529// A chunk for the import descriptor table.
530class DelayAddressChunk : public NonSectionChunk {
531public:
532 explicit DelayAddressChunk(COFFLinkerContext &ctx, Chunk *c)
533 : thunk(c), ctx(ctx) {
534 setAlignment(ctx.config.wordsize);
535 }
536 size_t getSize() const override { return ctx.config.wordsize; }
537
538 void writeTo(uint8_t *buf) const override {
539 if (ctx.config.is64()) {
540 write64le(P: buf, V: thunk->getRVA() + ctx.config.imageBase);
541 } else {
542 uint32_t bit = 0;
543 // Pointer to thumb code must have the LSB set, so adjust it.
544 if (ctx.config.machine == ARMNT)
545 bit = 1;
546 write32le(P: buf, V: (thunk->getRVA() + ctx.config.imageBase) | bit);
547 }
548 }
549
550 void getBaserels(std::vector<Baserel> *res) override {
551 res->emplace_back(args&: rva, args: ctx.config.machine);
552 }
553
554 Chunk *thunk;
555
556private:
557 const COFFLinkerContext &ctx;
558};
559
560// Export table
561// Read Microsoft PE/COFF spec 5.3 for details.
562
563// A chunk for the export descriptor table.
564class ExportDirectoryChunk : public NonSectionChunk {
565public:
566 ExportDirectoryChunk(int baseOrdinal, int maxOrdinal, int nameTabSize,
567 Chunk *d, Chunk *a, Chunk *n, Chunk *o)
568 : baseOrdinal(baseOrdinal), maxOrdinal(maxOrdinal),
569 nameTabSize(nameTabSize), dllName(d), addressTab(a), nameTab(n),
570 ordinalTab(o) {}
571
572 size_t getSize() const override {
573 return sizeof(export_directory_table_entry);
574 }
575
576 void writeTo(uint8_t *buf) const override {
577 memset(s: buf, c: 0, n: getSize());
578
579 auto *e = (export_directory_table_entry *)(buf);
580 e->NameRVA = dllName->getRVA();
581 e->OrdinalBase = baseOrdinal;
582 e->AddressTableEntries = (maxOrdinal - baseOrdinal) + 1;
583 e->NumberOfNamePointers = nameTabSize;
584 e->ExportAddressTableRVA = addressTab->getRVA();
585 e->NamePointerRVA = nameTab->getRVA();
586 e->OrdinalTableRVA = ordinalTab->getRVA();
587 }
588
589 uint16_t baseOrdinal;
590 uint16_t maxOrdinal;
591 uint16_t nameTabSize;
592 Chunk *dllName;
593 Chunk *addressTab;
594 Chunk *nameTab;
595 Chunk *ordinalTab;
596};
597
598class AddressTableChunk : public NonSectionChunk {
599public:
600 explicit AddressTableChunk(COFFLinkerContext &ctx, size_t baseOrdinal,
601 size_t maxOrdinal)
602 : baseOrdinal(baseOrdinal), size((maxOrdinal - baseOrdinal) + 1),
603 ctx(ctx) {}
604 size_t getSize() const override { return size * 4; }
605
606 void writeTo(uint8_t *buf) const override {
607 memset(s: buf, c: 0, n: getSize());
608
609 for (const Export &e : ctx.config.exports) {
610 assert(e.ordinal >= baseOrdinal && "Export symbol has invalid ordinal");
611 // Subtract the OrdinalBase to get the index.
612 uint8_t *p = buf + (e.ordinal - baseOrdinal) * 4;
613 uint32_t bit = 0;
614 // Pointer to thumb code must have the LSB set, so adjust it.
615 if (ctx.config.machine == ARMNT && !e.data)
616 bit = 1;
617 if (e.forwardChunk) {
618 write32le(P: p, V: e.forwardChunk->getRVA() | bit);
619 } else {
620 assert(cast<Defined>(e.sym)->getRVA() != 0 &&
621 "Exported symbol unmapped");
622 write32le(P: p, V: cast<Defined>(Val: e.sym)->getRVA() | bit);
623 }
624 }
625 }
626
627private:
628 size_t baseOrdinal;
629 size_t size;
630 const COFFLinkerContext &ctx;
631};
632
633class NamePointersChunk : public NonSectionChunk {
634public:
635 explicit NamePointersChunk(std::vector<Chunk *> &v) : chunks(v) {}
636 size_t getSize() const override { return chunks.size() * 4; }
637
638 void writeTo(uint8_t *buf) const override {
639 for (Chunk *c : chunks) {
640 write32le(P: buf, V: c->getRVA());
641 buf += 4;
642 }
643 }
644
645private:
646 std::vector<Chunk *> chunks;
647};
648
649class ExportOrdinalChunk : public NonSectionChunk {
650public:
651 explicit ExportOrdinalChunk(const COFFLinkerContext &ctx, size_t baseOrdinal,
652 size_t tableSize)
653 : baseOrdinal(baseOrdinal), size(tableSize), ctx(ctx) {}
654 size_t getSize() const override { return size * 2; }
655
656 void writeTo(uint8_t *buf) const override {
657 for (const Export &e : ctx.config.exports) {
658 if (e.noname)
659 continue;
660 assert(e.ordinal >= baseOrdinal && "Export symbol has invalid ordinal");
661 // This table stores unbiased indices, so subtract OrdinalBase.
662 write16le(P: buf, V: e.ordinal - baseOrdinal);
663 buf += 2;
664 }
665 }
666
667private:
668 size_t baseOrdinal;
669 size_t size;
670 const COFFLinkerContext &ctx;
671};
672
673} // anonymous namespace
674
675void IdataContents::create(COFFLinkerContext &ctx) {
676 std::vector<std::vector<DefinedImportData *>> v = binImports(ctx, imports);
677
678 // Create .idata contents for each DLL.
679 for (std::vector<DefinedImportData *> &syms : v) {
680 // Create lookup and address tables. If they have external names,
681 // we need to create hintName chunks to store the names.
682 // If they don't (if they are import-by-ordinals), we store only
683 // ordinal values to the table.
684 size_t base = lookups.size();
685 for (DefinedImportData *s : syms) {
686 uint16_t ord = s->getOrdinal();
687 if (s->getExternalName().empty()) {
688 lookups.push_back(x: make<OrdinalOnlyChunk>(args&: ctx, args&: ord));
689 addresses.push_back(x: make<OrdinalOnlyChunk>(args&: ctx, args&: ord));
690 continue;
691 }
692 auto *c = make<HintNameChunk>(args: s->getExternalName(), args&: ord);
693 lookups.push_back(x: make<LookupChunk>(args&: ctx, args&: c));
694 addresses.push_back(x: make<LookupChunk>(args&: ctx, args&: c));
695 hints.push_back(x: c);
696 }
697 // Terminate with null values.
698 lookups.push_back(x: make<NullChunk>(args&: ctx.config.wordsize));
699 addresses.push_back(x: make<NullChunk>(args&: ctx.config.wordsize));
700
701 for (int i = 0, e = syms.size(); i < e; ++i)
702 syms[i]->setLocation(addresses[base + i]);
703
704 // Create the import table header.
705 dllNames.push_back(x: make<StringChunk>(args: syms[0]->getDLLName()));
706 auto *dir = make<ImportDirectoryChunk>(args&: dllNames.back());
707 dir->lookupTab = lookups[base];
708 dir->addressTab = addresses[base];
709 dirs.push_back(x: dir);
710 }
711 // Add null terminator.
712 dirs.push_back(x: make<NullChunk>(args: sizeof(ImportDirectoryTableEntry)));
713}
714
715std::vector<Chunk *> DelayLoadContents::getChunks() {
716 std::vector<Chunk *> v;
717 v.insert(position: v.end(), first: dirs.begin(), last: dirs.end());
718 v.insert(position: v.end(), first: names.begin(), last: names.end());
719 v.insert(position: v.end(), first: hintNames.begin(), last: hintNames.end());
720 v.insert(position: v.end(), first: dllNames.begin(), last: dllNames.end());
721 return v;
722}
723
724std::vector<Chunk *> DelayLoadContents::getDataChunks() {
725 std::vector<Chunk *> v;
726 v.insert(position: v.end(), first: moduleHandles.begin(), last: moduleHandles.end());
727 v.insert(position: v.end(), first: addresses.begin(), last: addresses.end());
728 return v;
729}
730
731uint64_t DelayLoadContents::getDirSize() {
732 return dirs.size() * sizeof(delay_import_directory_table_entry);
733}
734
735void DelayLoadContents::create(Defined *h) {
736 helper = h;
737 std::vector<std::vector<DefinedImportData *>> v = binImports(ctx, imports);
738
739 Chunk *unwind = newTailMergeUnwindInfoChunk();
740
741 // Create .didat contents for each DLL.
742 for (std::vector<DefinedImportData *> &syms : v) {
743 // Create the delay import table header.
744 dllNames.push_back(x: make<StringChunk>(args: syms[0]->getDLLName()));
745 auto *dir = make<DelayDirectoryChunk>(args&: dllNames.back());
746
747 size_t base = addresses.size();
748 Chunk *tm = newTailMergeChunk(dir);
749 Chunk *pdataChunk = unwind ? newTailMergePDataChunk(tm, unwind) : nullptr;
750 for (DefinedImportData *s : syms) {
751 Chunk *t = newThunkChunk(s, tailMerge: tm);
752 auto *a = make<DelayAddressChunk>(args&: ctx, args&: t);
753 addresses.push_back(x: a);
754 thunks.push_back(x: t);
755 StringRef extName = s->getExternalName();
756 if (extName.empty()) {
757 names.push_back(x: make<OrdinalOnlyChunk>(args&: ctx, args: s->getOrdinal()));
758 } else {
759 auto *c = make<HintNameChunk>(args&: extName, args: 0);
760 names.push_back(x: make<LookupChunk>(args&: ctx, args&: c));
761 hintNames.push_back(x: c);
762 // Add a synthetic symbol for this load thunk, using the "__imp___load"
763 // prefix, in case this thunk needs to be added to the list of valid
764 // call targets for Control Flow Guard.
765 StringRef symName = saver().save(S: "__imp___load_" + extName);
766 s->loadThunkSym =
767 cast<DefinedSynthetic>(Val: ctx.symtab.addSynthetic(n: symName, c: t));
768 }
769 }
770 thunks.push_back(x: tm);
771 if (pdataChunk)
772 pdata.push_back(x: pdataChunk);
773 StringRef tmName =
774 saver().save(S: "__tailMerge_" + syms[0]->getDLLName().lower());
775 ctx.symtab.addSynthetic(n: tmName, c: tm);
776 // Terminate with null values.
777 addresses.push_back(x: make<NullChunk>(args: 8));
778 names.push_back(x: make<NullChunk>(args: 8));
779
780 for (int i = 0, e = syms.size(); i < e; ++i)
781 syms[i]->setLocation(addresses[base + i]);
782 auto *mh = make<NullChunk>(args: 8);
783 mh->setAlignment(8);
784 moduleHandles.push_back(x: mh);
785
786 // Fill the delay import table header fields.
787 dir->moduleHandle = mh;
788 dir->addressTab = addresses[base];
789 dir->nameTab = names[base];
790 dirs.push_back(x: dir);
791 }
792
793 if (unwind)
794 unwindinfo.push_back(x: unwind);
795 // Add null terminator.
796 dirs.push_back(x: make<NullChunk>(args: sizeof(delay_import_directory_table_entry)));
797}
798
799Chunk *DelayLoadContents::newTailMergeChunk(Chunk *dir) {
800 switch (ctx.config.machine) {
801 case AMD64:
802 return make<TailMergeChunkX64>(args&: dir, args&: helper);
803 case I386:
804 return make<TailMergeChunkX86>(args&: ctx, args&: dir, args&: helper);
805 case ARMNT:
806 return make<TailMergeChunkARM>(args&: ctx, args&: dir, args&: helper);
807 case ARM64:
808 return make<TailMergeChunkARM64>(args&: dir, args&: helper);
809 default:
810 llvm_unreachable("unsupported machine type");
811 }
812}
813
814Chunk *DelayLoadContents::newTailMergeUnwindInfoChunk() {
815 switch (ctx.config.machine) {
816 case AMD64:
817 return make<TailMergeUnwindInfoX64>();
818 // FIXME: Add support for other architectures.
819 default:
820 return nullptr; // Just don't generate unwind info.
821 }
822}
823Chunk *DelayLoadContents::newTailMergePDataChunk(Chunk *tm, Chunk *unwind) {
824 switch (ctx.config.machine) {
825 case AMD64:
826 return make<TailMergePDataChunkX64>(args&: tm, args&: unwind);
827 // FIXME: Add support for other architectures.
828 default:
829 return nullptr; // Just don't generate unwind info.
830 }
831}
832
833Chunk *DelayLoadContents::newThunkChunk(DefinedImportData *s,
834 Chunk *tailMerge) {
835 switch (ctx.config.machine) {
836 case AMD64:
837 return make<ThunkChunkX64>(args&: s, args&: tailMerge);
838 case I386:
839 return make<ThunkChunkX86>(args&: ctx, args&: s, args&: tailMerge);
840 case ARMNT:
841 return make<ThunkChunkARM>(args&: ctx, args&: s, args&: tailMerge);
842 case ARM64:
843 return make<ThunkChunkARM64>(args&: s, args&: tailMerge);
844 default:
845 llvm_unreachable("unsupported machine type");
846 }
847}
848
849EdataContents::EdataContents(COFFLinkerContext &ctx) : ctx(ctx) {
850 unsigned baseOrdinal = 1 << 16, maxOrdinal = 0;
851 for (Export &e : ctx.config.exports) {
852 baseOrdinal = std::min(a: baseOrdinal, b: (unsigned)e.ordinal);
853 maxOrdinal = std::max(a: maxOrdinal, b: (unsigned)e.ordinal);
854 }
855 // Ordinals must start at 1 as suggested in:
856 // https://learn.microsoft.com/en-us/cpp/build/reference/export-exports-a-function?view=msvc-170
857 assert(baseOrdinal >= 1);
858
859 auto *dllName = make<StringChunk>(args: sys::path::filename(path: ctx.config.outputFile));
860 auto *addressTab = make<AddressTableChunk>(args&: ctx, args&: baseOrdinal, args&: maxOrdinal);
861 std::vector<Chunk *> names;
862 for (Export &e : ctx.config.exports)
863 if (!e.noname)
864 names.push_back(x: make<StringChunk>(args&: e.exportName));
865
866 std::vector<Chunk *> forwards;
867 for (Export &e : ctx.config.exports) {
868 if (e.forwardTo.empty())
869 continue;
870 e.forwardChunk = make<StringChunk>(args&: e.forwardTo);
871 forwards.push_back(x: e.forwardChunk);
872 }
873
874 auto *nameTab = make<NamePointersChunk>(args&: names);
875 auto *ordinalTab = make<ExportOrdinalChunk>(args&: ctx, args&: baseOrdinal, args: names.size());
876 auto *dir =
877 make<ExportDirectoryChunk>(args&: baseOrdinal, args&: maxOrdinal, args: names.size(), args&: dllName,
878 args&: addressTab, args&: nameTab, args&: ordinalTab);
879 chunks.push_back(x: dir);
880 chunks.push_back(x: dllName);
881 chunks.push_back(x: addressTab);
882 chunks.push_back(x: nameTab);
883 chunks.push_back(x: ordinalTab);
884 chunks.insert(position: chunks.end(), first: names.begin(), last: names.end());
885 chunks.insert(position: chunks.end(), first: forwards.begin(), last: forwards.end());
886}
887
888} // namespace lld::coff
889

source code of lld/COFF/DLL.cpp