1 //===- yaml2macho - Convert YAML to a Mach object file --------------------===//
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 /// \file
10 /// The Mach component of yaml2obj.
11 ///
12 //===----------------------------------------------------------------------===//
13
14 #include "llvm/BinaryFormat/MachO.h"
15 #include "llvm/ObjectYAML/DWARFEmitter.h"
16 #include "llvm/ObjectYAML/ObjectYAML.h"
17 #include "llvm/ObjectYAML/yaml2obj.h"
18 #include "llvm/Support/Errc.h"
19 #include "llvm/Support/Error.h"
20 #include "llvm/Support/LEB128.h"
21 #include "llvm/Support/YAMLTraits.h"
22 #include "llvm/Support/raw_ostream.h"
23
24 #include "llvm/Support/Format.h"
25
26 using namespace llvm;
27
28 namespace {
29
30 class MachOWriter {
31 public:
MachOWriter(MachOYAML::Object & Obj)32 MachOWriter(MachOYAML::Object &Obj) : Obj(Obj), fileStart(0) {
33 is64Bit = Obj.Header.magic == MachO::MH_MAGIC_64 ||
34 Obj.Header.magic == MachO::MH_CIGAM_64;
35 memset(reinterpret_cast<void *>(&Header), 0, sizeof(MachO::mach_header_64));
36 }
37
38 Error writeMachO(raw_ostream &OS);
39
40 private:
41 void writeHeader(raw_ostream &OS);
42 void writeLoadCommands(raw_ostream &OS);
43 Error writeSectionData(raw_ostream &OS);
44 void writeRelocations(raw_ostream &OS);
45 void writeLinkEditData(raw_ostream &OS);
46
47 void writeBindOpcodes(raw_ostream &OS,
48 std::vector<MachOYAML::BindOpcode> &BindOpcodes);
49 // LinkEdit writers
50 void writeRebaseOpcodes(raw_ostream &OS);
51 void writeBasicBindOpcodes(raw_ostream &OS);
52 void writeWeakBindOpcodes(raw_ostream &OS);
53 void writeLazyBindOpcodes(raw_ostream &OS);
54 void writeNameList(raw_ostream &OS);
55 void writeStringTable(raw_ostream &OS);
56 void writeExportTrie(raw_ostream &OS);
57
58 void dumpExportEntry(raw_ostream &OS, MachOYAML::ExportEntry &Entry);
59 void ZeroToOffset(raw_ostream &OS, size_t offset);
60
61 MachOYAML::Object &Obj;
62 bool is64Bit;
63 uint64_t fileStart;
64 MachO::mach_header_64 Header;
65
66 // Old PPC Object Files didn't have __LINKEDIT segments, the data was just
67 // stuck at the end of the file.
68 bool FoundLinkEditSeg = false;
69 };
70
writeMachO(raw_ostream & OS)71 Error MachOWriter::writeMachO(raw_ostream &OS) {
72 fileStart = OS.tell();
73 writeHeader(OS);
74 writeLoadCommands(OS);
75 if (Error Err = writeSectionData(OS))
76 return Err;
77 writeRelocations(OS);
78 if (!FoundLinkEditSeg)
79 writeLinkEditData(OS);
80 return Error::success();
81 }
82
writeHeader(raw_ostream & OS)83 void MachOWriter::writeHeader(raw_ostream &OS) {
84 Header.magic = Obj.Header.magic;
85 Header.cputype = Obj.Header.cputype;
86 Header.cpusubtype = Obj.Header.cpusubtype;
87 Header.filetype = Obj.Header.filetype;
88 Header.ncmds = Obj.Header.ncmds;
89 Header.sizeofcmds = Obj.Header.sizeofcmds;
90 Header.flags = Obj.Header.flags;
91 Header.reserved = Obj.Header.reserved;
92
93 if (Obj.IsLittleEndian != sys::IsLittleEndianHost)
94 MachO::swapStruct(Header);
95
96 auto header_size =
97 is64Bit ? sizeof(MachO::mach_header_64) : sizeof(MachO::mach_header);
98 OS.write((const char *)&Header, header_size);
99 }
100
101 template <typename SectionType>
constructSection(MachOYAML::Section Sec)102 SectionType constructSection(MachOYAML::Section Sec) {
103 SectionType TempSec;
104 memcpy(reinterpret_cast<void *>(&TempSec.sectname[0]), &Sec.sectname[0], 16);
105 memcpy(reinterpret_cast<void *>(&TempSec.segname[0]), &Sec.segname[0], 16);
106 TempSec.addr = Sec.addr;
107 TempSec.size = Sec.size;
108 TempSec.offset = Sec.offset;
109 TempSec.align = Sec.align;
110 TempSec.reloff = Sec.reloff;
111 TempSec.nreloc = Sec.nreloc;
112 TempSec.flags = Sec.flags;
113 TempSec.reserved1 = Sec.reserved1;
114 TempSec.reserved2 = Sec.reserved2;
115 return TempSec;
116 }
117
118 template <typename StructType>
writeLoadCommandData(MachOYAML::LoadCommand & LC,raw_ostream & OS,bool IsLittleEndian)119 size_t writeLoadCommandData(MachOYAML::LoadCommand &LC, raw_ostream &OS,
120 bool IsLittleEndian) {
121 return 0;
122 }
123
124 template <>
writeLoadCommandData(MachOYAML::LoadCommand & LC,raw_ostream & OS,bool IsLittleEndian)125 size_t writeLoadCommandData<MachO::segment_command>(MachOYAML::LoadCommand &LC,
126 raw_ostream &OS,
127 bool IsLittleEndian) {
128 size_t BytesWritten = 0;
129 for (const auto &Sec : LC.Sections) {
130 auto TempSec = constructSection<MachO::section>(Sec);
131 if (IsLittleEndian != sys::IsLittleEndianHost)
132 MachO::swapStruct(TempSec);
133 OS.write(reinterpret_cast<const char *>(&(TempSec)),
134 sizeof(MachO::section));
135 BytesWritten += sizeof(MachO::section);
136 }
137 return BytesWritten;
138 }
139
140 template <>
writeLoadCommandData(MachOYAML::LoadCommand & LC,raw_ostream & OS,bool IsLittleEndian)141 size_t writeLoadCommandData<MachO::segment_command_64>(
142 MachOYAML::LoadCommand &LC, raw_ostream &OS, bool IsLittleEndian) {
143 size_t BytesWritten = 0;
144 for (const auto &Sec : LC.Sections) {
145 auto TempSec = constructSection<MachO::section_64>(Sec);
146 TempSec.reserved3 = Sec.reserved3;
147 if (IsLittleEndian != sys::IsLittleEndianHost)
148 MachO::swapStruct(TempSec);
149 OS.write(reinterpret_cast<const char *>(&(TempSec)),
150 sizeof(MachO::section_64));
151 BytesWritten += sizeof(MachO::section_64);
152 }
153 return BytesWritten;
154 }
155
writePayloadString(MachOYAML::LoadCommand & LC,raw_ostream & OS)156 size_t writePayloadString(MachOYAML::LoadCommand &LC, raw_ostream &OS) {
157 size_t BytesWritten = 0;
158 if (!LC.Content.empty()) {
159 OS.write(LC.Content.c_str(), LC.Content.length());
160 BytesWritten = LC.Content.length();
161 }
162 return BytesWritten;
163 }
164
165 template <>
writeLoadCommandData(MachOYAML::LoadCommand & LC,raw_ostream & OS,bool IsLittleEndian)166 size_t writeLoadCommandData<MachO::dylib_command>(MachOYAML::LoadCommand &LC,
167 raw_ostream &OS,
168 bool IsLittleEndian) {
169 return writePayloadString(LC, OS);
170 }
171
172 template <>
writeLoadCommandData(MachOYAML::LoadCommand & LC,raw_ostream & OS,bool IsLittleEndian)173 size_t writeLoadCommandData<MachO::dylinker_command>(MachOYAML::LoadCommand &LC,
174 raw_ostream &OS,
175 bool IsLittleEndian) {
176 return writePayloadString(LC, OS);
177 }
178
179 template <>
writeLoadCommandData(MachOYAML::LoadCommand & LC,raw_ostream & OS,bool IsLittleEndian)180 size_t writeLoadCommandData<MachO::rpath_command>(MachOYAML::LoadCommand &LC,
181 raw_ostream &OS,
182 bool IsLittleEndian) {
183 return writePayloadString(LC, OS);
184 }
185
186 template <>
writeLoadCommandData(MachOYAML::LoadCommand & LC,raw_ostream & OS,bool IsLittleEndian)187 size_t writeLoadCommandData<MachO::build_version_command>(
188 MachOYAML::LoadCommand &LC, raw_ostream &OS, bool IsLittleEndian) {
189 size_t BytesWritten = 0;
190 for (const auto &T : LC.Tools) {
191 struct MachO::build_tool_version tool = T;
192 if (IsLittleEndian != sys::IsLittleEndianHost)
193 MachO::swapStruct(tool);
194 OS.write(reinterpret_cast<const char *>(&tool),
195 sizeof(MachO::build_tool_version));
196 BytesWritten += sizeof(MachO::build_tool_version);
197 }
198 return BytesWritten;
199 }
200
ZeroFillBytes(raw_ostream & OS,size_t Size)201 void ZeroFillBytes(raw_ostream &OS, size_t Size) {
202 std::vector<uint8_t> FillData(Size, 0);
203 OS.write(reinterpret_cast<char *>(FillData.data()), Size);
204 }
205
Fill(raw_ostream & OS,size_t Size,uint32_t Data)206 void Fill(raw_ostream &OS, size_t Size, uint32_t Data) {
207 std::vector<uint32_t> FillData((Size / 4) + 1, Data);
208 OS.write(reinterpret_cast<char *>(FillData.data()), Size);
209 }
210
ZeroToOffset(raw_ostream & OS,size_t Offset)211 void MachOWriter::ZeroToOffset(raw_ostream &OS, size_t Offset) {
212 auto currOffset = OS.tell() - fileStart;
213 if (currOffset < Offset)
214 ZeroFillBytes(OS, Offset - currOffset);
215 }
216
writeLoadCommands(raw_ostream & OS)217 void MachOWriter::writeLoadCommands(raw_ostream &OS) {
218 for (auto &LC : Obj.LoadCommands) {
219 size_t BytesWritten = 0;
220 llvm::MachO::macho_load_command Data = LC.Data;
221
222 #define HANDLE_LOAD_COMMAND(LCName, LCValue, LCStruct) \
223 case MachO::LCName: \
224 if (Obj.IsLittleEndian != sys::IsLittleEndianHost) \
225 MachO::swapStruct(Data.LCStruct##_data); \
226 OS.write(reinterpret_cast<const char *>(&(Data.LCStruct##_data)), \
227 sizeof(MachO::LCStruct)); \
228 BytesWritten = sizeof(MachO::LCStruct); \
229 BytesWritten += \
230 writeLoadCommandData<MachO::LCStruct>(LC, OS, Obj.IsLittleEndian); \
231 break;
232
233 switch (LC.Data.load_command_data.cmd) {
234 default:
235 if (Obj.IsLittleEndian != sys::IsLittleEndianHost)
236 MachO::swapStruct(Data.load_command_data);
237 OS.write(reinterpret_cast<const char *>(&(Data.load_command_data)),
238 sizeof(MachO::load_command));
239 BytesWritten = sizeof(MachO::load_command);
240 BytesWritten +=
241 writeLoadCommandData<MachO::load_command>(LC, OS, Obj.IsLittleEndian);
242 break;
243 #include "llvm/BinaryFormat/MachO.def"
244 }
245
246 if (LC.PayloadBytes.size() > 0) {
247 OS.write(reinterpret_cast<const char *>(LC.PayloadBytes.data()),
248 LC.PayloadBytes.size());
249 BytesWritten += LC.PayloadBytes.size();
250 }
251
252 if (LC.ZeroPadBytes > 0) {
253 ZeroFillBytes(OS, LC.ZeroPadBytes);
254 BytesWritten += LC.ZeroPadBytes;
255 }
256
257 // Fill remaining bytes with 0. This will only get hit in partially
258 // specified test cases.
259 auto BytesRemaining = LC.Data.load_command_data.cmdsize - BytesWritten;
260 if (BytesRemaining > 0) {
261 ZeroFillBytes(OS, BytesRemaining);
262 }
263 }
264 }
265
writeSectionData(raw_ostream & OS)266 Error MachOWriter::writeSectionData(raw_ostream &OS) {
267 for (auto &LC : Obj.LoadCommands) {
268 switch (LC.Data.load_command_data.cmd) {
269 case MachO::LC_SEGMENT:
270 case MachO::LC_SEGMENT_64:
271 uint64_t segOff = is64Bit ? LC.Data.segment_command_64_data.fileoff
272 : LC.Data.segment_command_data.fileoff;
273 if (0 ==
274 strncmp(&LC.Data.segment_command_data.segname[0], "__LINKEDIT", 16)) {
275 FoundLinkEditSeg = true;
276 writeLinkEditData(OS);
277 }
278 for (auto &Sec : LC.Sections) {
279 ZeroToOffset(OS, Sec.offset);
280 // Zero Fill any data between the end of the last thing we wrote and the
281 // start of this section.
282 if (OS.tell() - fileStart > Sec.offset && Sec.offset != (uint32_t)0)
283 return createStringError(
284 errc::invalid_argument,
285 "wrote too much data somewhere, section offsets don't line up");
286
287 StringRef SectName(Sec.sectname,
288 strnlen(Sec.sectname, sizeof(Sec.sectname)));
289 // If the section's content is specified in the 'DWARF' entry, we will
290 // emit it regardless of the section's segname.
291 if (Obj.DWARF.getNonEmptySectionNames().count(SectName.substr(2))) {
292 if (Sec.content)
293 return createStringError(errc::invalid_argument,
294 "cannot specify section '" + SectName +
295 "' contents in the 'DWARF' entry and "
296 "the 'content' at the same time");
297 auto EmitFunc = DWARFYAML::getDWARFEmitterByName(SectName.substr(2));
298 if (Error Err = EmitFunc(OS, Obj.DWARF))
299 return Err;
300 continue;
301 }
302
303 // Skip if it's a virtual section.
304 if (MachO::isVirtualSection(Sec.flags & MachO::SECTION_TYPE))
305 continue;
306
307 if (Sec.content) {
308 yaml::BinaryRef Content = *Sec.content;
309 Content.writeAsBinary(OS);
310 ZeroFillBytes(OS, Sec.size - Content.binary_size());
311 } else {
312 // Fill section data with 0xDEADBEEF.
313 Fill(OS, Sec.size, 0xDEADBEEFu);
314 }
315 }
316 uint64_t segSize = is64Bit ? LC.Data.segment_command_64_data.filesize
317 : LC.Data.segment_command_data.filesize;
318 ZeroToOffset(OS, segOff + segSize);
319 break;
320 }
321 }
322
323 return Error::success();
324 }
325
326 // The implementation of makeRelocationInfo and makeScatteredRelocationInfo is
327 // consistent with how libObject parses MachO binary files. For the reference
328 // see getStruct, getRelocation, getPlainRelocationPCRel,
329 // getPlainRelocationLength and related methods in MachOObjectFile.cpp
330 static MachO::any_relocation_info
makeRelocationInfo(const MachOYAML::Relocation & R,bool IsLE)331 makeRelocationInfo(const MachOYAML::Relocation &R, bool IsLE) {
332 assert(!R.is_scattered && "non-scattered relocation expected");
333 MachO::any_relocation_info MRE;
334 MRE.r_word0 = R.address;
335 if (IsLE)
336 MRE.r_word1 = ((unsigned)R.symbolnum << 0) | ((unsigned)R.is_pcrel << 24) |
337 ((unsigned)R.length << 25) | ((unsigned)R.is_extern << 27) |
338 ((unsigned)R.type << 28);
339 else
340 MRE.r_word1 = ((unsigned)R.symbolnum << 8) | ((unsigned)R.is_pcrel << 7) |
341 ((unsigned)R.length << 5) | ((unsigned)R.is_extern << 4) |
342 ((unsigned)R.type << 0);
343 return MRE;
344 }
345
346 static MachO::any_relocation_info
makeScatteredRelocationInfo(const MachOYAML::Relocation & R)347 makeScatteredRelocationInfo(const MachOYAML::Relocation &R) {
348 assert(R.is_scattered && "scattered relocation expected");
349 MachO::any_relocation_info MRE;
350 MRE.r_word0 = (((unsigned)R.address << 0) | ((unsigned)R.type << 24) |
351 ((unsigned)R.length << 28) | ((unsigned)R.is_pcrel << 30) |
352 MachO::R_SCATTERED);
353 MRE.r_word1 = R.value;
354 return MRE;
355 }
356
writeRelocations(raw_ostream & OS)357 void MachOWriter::writeRelocations(raw_ostream &OS) {
358 for (const MachOYAML::LoadCommand &LC : Obj.LoadCommands) {
359 switch (LC.Data.load_command_data.cmd) {
360 case MachO::LC_SEGMENT:
361 case MachO::LC_SEGMENT_64:
362 for (const MachOYAML::Section &Sec : LC.Sections) {
363 if (Sec.relocations.empty())
364 continue;
365 ZeroToOffset(OS, Sec.reloff);
366 for (const MachOYAML::Relocation &R : Sec.relocations) {
367 MachO::any_relocation_info MRE =
368 R.is_scattered ? makeScatteredRelocationInfo(R)
369 : makeRelocationInfo(R, Obj.IsLittleEndian);
370 if (Obj.IsLittleEndian != sys::IsLittleEndianHost)
371 MachO::swapStruct(MRE);
372 OS.write(reinterpret_cast<const char *>(&MRE),
373 sizeof(MachO::any_relocation_info));
374 }
375 }
376 }
377 }
378 }
379
writeBindOpcodes(raw_ostream & OS,std::vector<MachOYAML::BindOpcode> & BindOpcodes)380 void MachOWriter::writeBindOpcodes(
381 raw_ostream &OS, std::vector<MachOYAML::BindOpcode> &BindOpcodes) {
382
383 for (auto Opcode : BindOpcodes) {
384 uint8_t OpByte = Opcode.Opcode | Opcode.Imm;
385 OS.write(reinterpret_cast<char *>(&OpByte), 1);
386 for (auto Data : Opcode.ULEBExtraData) {
387 encodeULEB128(Data, OS);
388 }
389 for (auto Data : Opcode.SLEBExtraData) {
390 encodeSLEB128(Data, OS);
391 }
392 if (!Opcode.Symbol.empty()) {
393 OS.write(Opcode.Symbol.data(), Opcode.Symbol.size());
394 OS.write('\0');
395 }
396 }
397 }
398
dumpExportEntry(raw_ostream & OS,MachOYAML::ExportEntry & Entry)399 void MachOWriter::dumpExportEntry(raw_ostream &OS,
400 MachOYAML::ExportEntry &Entry) {
401 encodeSLEB128(Entry.TerminalSize, OS);
402 if (Entry.TerminalSize > 0) {
403 encodeSLEB128(Entry.Flags, OS);
404 if (Entry.Flags & MachO::EXPORT_SYMBOL_FLAGS_REEXPORT) {
405 encodeSLEB128(Entry.Other, OS);
406 OS << Entry.ImportName;
407 OS.write('\0');
408 } else {
409 encodeSLEB128(Entry.Address, OS);
410 if (Entry.Flags & MachO::EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER)
411 encodeSLEB128(Entry.Other, OS);
412 }
413 }
414 OS.write(static_cast<uint8_t>(Entry.Children.size()));
415 for (auto EE : Entry.Children) {
416 OS << EE.Name;
417 OS.write('\0');
418 encodeSLEB128(EE.NodeOffset, OS);
419 }
420 for (auto EE : Entry.Children)
421 dumpExportEntry(OS, EE);
422 }
423
writeExportTrie(raw_ostream & OS)424 void MachOWriter::writeExportTrie(raw_ostream &OS) {
425 dumpExportEntry(OS, Obj.LinkEdit.ExportTrie);
426 }
427
428 template <typename NListType>
writeNListEntry(MachOYAML::NListEntry & NLE,raw_ostream & OS,bool IsLittleEndian)429 void writeNListEntry(MachOYAML::NListEntry &NLE, raw_ostream &OS,
430 bool IsLittleEndian) {
431 NListType ListEntry;
432 ListEntry.n_strx = NLE.n_strx;
433 ListEntry.n_type = NLE.n_type;
434 ListEntry.n_sect = NLE.n_sect;
435 ListEntry.n_desc = NLE.n_desc;
436 ListEntry.n_value = NLE.n_value;
437
438 if (IsLittleEndian != sys::IsLittleEndianHost)
439 MachO::swapStruct(ListEntry);
440 OS.write(reinterpret_cast<const char *>(&ListEntry), sizeof(NListType));
441 }
442
writeLinkEditData(raw_ostream & OS)443 void MachOWriter::writeLinkEditData(raw_ostream &OS) {
444 typedef void (MachOWriter::*writeHandler)(raw_ostream &);
445 typedef std::pair<uint64_t, writeHandler> writeOperation;
446 std::vector<writeOperation> WriteQueue;
447
448 MachO::dyld_info_command *DyldInfoOnlyCmd = 0;
449 MachO::symtab_command *SymtabCmd = 0;
450 for (auto &LC : Obj.LoadCommands) {
451 switch (LC.Data.load_command_data.cmd) {
452 case MachO::LC_SYMTAB:
453 SymtabCmd = &LC.Data.symtab_command_data;
454 WriteQueue.push_back(
455 std::make_pair(SymtabCmd->symoff, &MachOWriter::writeNameList));
456 WriteQueue.push_back(
457 std::make_pair(SymtabCmd->stroff, &MachOWriter::writeStringTable));
458 break;
459 case MachO::LC_DYLD_INFO_ONLY:
460 DyldInfoOnlyCmd = &LC.Data.dyld_info_command_data;
461 WriteQueue.push_back(std::make_pair(DyldInfoOnlyCmd->rebase_off,
462 &MachOWriter::writeRebaseOpcodes));
463 WriteQueue.push_back(std::make_pair(DyldInfoOnlyCmd->bind_off,
464 &MachOWriter::writeBasicBindOpcodes));
465 WriteQueue.push_back(std::make_pair(DyldInfoOnlyCmd->weak_bind_off,
466 &MachOWriter::writeWeakBindOpcodes));
467 WriteQueue.push_back(std::make_pair(DyldInfoOnlyCmd->lazy_bind_off,
468 &MachOWriter::writeLazyBindOpcodes));
469 WriteQueue.push_back(std::make_pair(DyldInfoOnlyCmd->export_off,
470 &MachOWriter::writeExportTrie));
471 break;
472 }
473 }
474
475 llvm::sort(WriteQueue, [](const writeOperation &a, const writeOperation &b) {
476 return a.first < b.first;
477 });
478
479 for (auto writeOp : WriteQueue) {
480 ZeroToOffset(OS, writeOp.first);
481 (this->*writeOp.second)(OS);
482 }
483 }
484
writeRebaseOpcodes(raw_ostream & OS)485 void MachOWriter::writeRebaseOpcodes(raw_ostream &OS) {
486 MachOYAML::LinkEditData &LinkEdit = Obj.LinkEdit;
487
488 for (auto Opcode : LinkEdit.RebaseOpcodes) {
489 uint8_t OpByte = Opcode.Opcode | Opcode.Imm;
490 OS.write(reinterpret_cast<char *>(&OpByte), 1);
491 for (auto Data : Opcode.ExtraData)
492 encodeULEB128(Data, OS);
493 }
494 }
495
writeBasicBindOpcodes(raw_ostream & OS)496 void MachOWriter::writeBasicBindOpcodes(raw_ostream &OS) {
497 writeBindOpcodes(OS, Obj.LinkEdit.BindOpcodes);
498 }
499
writeWeakBindOpcodes(raw_ostream & OS)500 void MachOWriter::writeWeakBindOpcodes(raw_ostream &OS) {
501 writeBindOpcodes(OS, Obj.LinkEdit.WeakBindOpcodes);
502 }
503
writeLazyBindOpcodes(raw_ostream & OS)504 void MachOWriter::writeLazyBindOpcodes(raw_ostream &OS) {
505 writeBindOpcodes(OS, Obj.LinkEdit.LazyBindOpcodes);
506 }
507
writeNameList(raw_ostream & OS)508 void MachOWriter::writeNameList(raw_ostream &OS) {
509 for (auto NLE : Obj.LinkEdit.NameList) {
510 if (is64Bit)
511 writeNListEntry<MachO::nlist_64>(NLE, OS, Obj.IsLittleEndian);
512 else
513 writeNListEntry<MachO::nlist>(NLE, OS, Obj.IsLittleEndian);
514 }
515 }
516
writeStringTable(raw_ostream & OS)517 void MachOWriter::writeStringTable(raw_ostream &OS) {
518 for (auto Str : Obj.LinkEdit.StringTable) {
519 OS.write(Str.data(), Str.size());
520 OS.write('\0');
521 }
522 }
523
524 class UniversalWriter {
525 public:
UniversalWriter(yaml::YamlObjectFile & ObjectFile)526 UniversalWriter(yaml::YamlObjectFile &ObjectFile)
527 : ObjectFile(ObjectFile), fileStart(0) {}
528
529 Error writeMachO(raw_ostream &OS);
530
531 private:
532 void writeFatHeader(raw_ostream &OS);
533 void writeFatArchs(raw_ostream &OS);
534
535 void ZeroToOffset(raw_ostream &OS, size_t offset);
536
537 yaml::YamlObjectFile &ObjectFile;
538 uint64_t fileStart;
539 };
540
writeMachO(raw_ostream & OS)541 Error UniversalWriter::writeMachO(raw_ostream &OS) {
542 fileStart = OS.tell();
543 if (ObjectFile.MachO) {
544 MachOWriter Writer(*ObjectFile.MachO);
545 return Writer.writeMachO(OS);
546 }
547
548 writeFatHeader(OS);
549 writeFatArchs(OS);
550
551 auto &FatFile = *ObjectFile.FatMachO;
552 if (FatFile.FatArchs.size() < FatFile.Slices.size())
553 return createStringError(
554 errc::invalid_argument,
555 "cannot write 'Slices' if not described in 'FatArches'");
556
557 for (size_t i = 0; i < FatFile.Slices.size(); i++) {
558 ZeroToOffset(OS, FatFile.FatArchs[i].offset);
559 MachOWriter Writer(FatFile.Slices[i]);
560 if (Error Err = Writer.writeMachO(OS))
561 return Err;
562
563 auto SliceEnd = FatFile.FatArchs[i].offset + FatFile.FatArchs[i].size;
564 ZeroToOffset(OS, SliceEnd);
565 }
566
567 return Error::success();
568 }
569
writeFatHeader(raw_ostream & OS)570 void UniversalWriter::writeFatHeader(raw_ostream &OS) {
571 auto &FatFile = *ObjectFile.FatMachO;
572 MachO::fat_header header;
573 header.magic = FatFile.Header.magic;
574 header.nfat_arch = FatFile.Header.nfat_arch;
575 if (sys::IsLittleEndianHost)
576 swapStruct(header);
577 OS.write(reinterpret_cast<const char *>(&header), sizeof(MachO::fat_header));
578 }
579
580 template <typename FatArchType>
constructFatArch(MachOYAML::FatArch & Arch)581 FatArchType constructFatArch(MachOYAML::FatArch &Arch) {
582 FatArchType FatArch;
583 FatArch.cputype = Arch.cputype;
584 FatArch.cpusubtype = Arch.cpusubtype;
585 FatArch.offset = Arch.offset;
586 FatArch.size = Arch.size;
587 FatArch.align = Arch.align;
588 return FatArch;
589 }
590
591 template <typename StructType>
writeFatArch(MachOYAML::FatArch & LC,raw_ostream & OS)592 void writeFatArch(MachOYAML::FatArch &LC, raw_ostream &OS) {}
593
594 template <>
writeFatArch(MachOYAML::FatArch & Arch,raw_ostream & OS)595 void writeFatArch<MachO::fat_arch>(MachOYAML::FatArch &Arch, raw_ostream &OS) {
596 auto FatArch = constructFatArch<MachO::fat_arch>(Arch);
597 if (sys::IsLittleEndianHost)
598 swapStruct(FatArch);
599 OS.write(reinterpret_cast<const char *>(&FatArch), sizeof(MachO::fat_arch));
600 }
601
602 template <>
writeFatArch(MachOYAML::FatArch & Arch,raw_ostream & OS)603 void writeFatArch<MachO::fat_arch_64>(MachOYAML::FatArch &Arch,
604 raw_ostream &OS) {
605 auto FatArch = constructFatArch<MachO::fat_arch_64>(Arch);
606 FatArch.reserved = Arch.reserved;
607 if (sys::IsLittleEndianHost)
608 swapStruct(FatArch);
609 OS.write(reinterpret_cast<const char *>(&FatArch),
610 sizeof(MachO::fat_arch_64));
611 }
612
writeFatArchs(raw_ostream & OS)613 void UniversalWriter::writeFatArchs(raw_ostream &OS) {
614 auto &FatFile = *ObjectFile.FatMachO;
615 bool is64Bit = FatFile.Header.magic == MachO::FAT_MAGIC_64;
616 for (auto Arch : FatFile.FatArchs) {
617 if (is64Bit)
618 writeFatArch<MachO::fat_arch_64>(Arch, OS);
619 else
620 writeFatArch<MachO::fat_arch>(Arch, OS);
621 }
622 }
623
ZeroToOffset(raw_ostream & OS,size_t Offset)624 void UniversalWriter::ZeroToOffset(raw_ostream &OS, size_t Offset) {
625 auto currOffset = OS.tell() - fileStart;
626 if (currOffset < Offset)
627 ZeroFillBytes(OS, Offset - currOffset);
628 }
629
630 } // end anonymous namespace
631
632 namespace llvm {
633 namespace yaml {
634
yaml2macho(YamlObjectFile & Doc,raw_ostream & Out,ErrorHandler EH)635 bool yaml2macho(YamlObjectFile &Doc, raw_ostream &Out, ErrorHandler EH) {
636 UniversalWriter Writer(Doc);
637 if (Error Err = Writer.writeMachO(Out)) {
638 handleAllErrors(std::move(Err),
639 [&](const ErrorInfoBase &Err) { EH(Err.message()); });
640 return false;
641 }
642 return true;
643 }
644
645 } // namespace yaml
646 } // namespace llvm
647