1//===- ArchiveWriter.cpp - ar File Format implementation --------*- C++ -*-===//
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 the writeArchive function.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/Object/ArchiveWriter.h"
14#include "llvm/ADT/ArrayRef.h"
15#include "llvm/ADT/StringMap.h"
16#include "llvm/ADT/StringRef.h"
17#include "llvm/BinaryFormat/Magic.h"
18#include "llvm/IR/LLVMContext.h"
19#include "llvm/Object/Archive.h"
20#include "llvm/Object/COFF.h"
21#include "llvm/Object/COFFImportFile.h"
22#include "llvm/Object/Error.h"
23#include "llvm/Object/IRObjectFile.h"
24#include "llvm/Object/MachO.h"
25#include "llvm/Object/ObjectFile.h"
26#include "llvm/Object/SymbolicFile.h"
27#include "llvm/Object/XCOFFObjectFile.h"
28#include "llvm/Support/Alignment.h"
29#include "llvm/Support/EndianStream.h"
30#include "llvm/Support/Errc.h"
31#include "llvm/Support/ErrorHandling.h"
32#include "llvm/Support/Format.h"
33#include "llvm/Support/MathExtras.h"
34#include "llvm/Support/Path.h"
35#include "llvm/Support/SmallVectorMemoryBuffer.h"
36#include "llvm/Support/raw_ostream.h"
37
38#include <cerrno>
39#include <map>
40
41#if !defined(_MSC_VER) && !defined(__MINGW32__)
42#include <unistd.h>
43#else
44#include <io.h>
45#endif
46
47using namespace llvm;
48using namespace llvm::object;
49
50struct SymMap {
51  bool UseECMap;
52  std::map<std::string, uint16_t> Map;
53  std::map<std::string, uint16_t> ECMap;
54};
55
56NewArchiveMember::NewArchiveMember(MemoryBufferRef BufRef)
57    : Buf(MemoryBuffer::getMemBuffer(BufRef, false)),
58      MemberName(BufRef.getBufferIdentifier()) {}
59
60object::Archive::Kind NewArchiveMember::detectKindFromObject() const {
61  auto MemBufferRef = this->Buf->getMemBufferRef();
62  Expected<std::unique_ptr<object::ObjectFile>> OptionalObject =
63      object::ObjectFile::createObjectFile(MemBufferRef);
64
65  if (OptionalObject)
66    return isa<object::MachOObjectFile>(**OptionalObject)
67               ? object::Archive::K_DARWIN
68               : (isa<object::XCOFFObjectFile>(**OptionalObject)
69                      ? object::Archive::K_AIXBIG
70                      : object::Archive::K_GNU);
71
72  // Squelch the error in case we had a non-object file.
73  consumeError(OptionalObject.takeError());
74
75  // If we're adding a bitcode file to the archive, detect the Archive kind
76  // based on the target triple.
77  LLVMContext Context;
78  if (identify_magic(MemBufferRef.getBuffer()) == file_magic::bitcode) {
79    if (auto ObjOrErr = object::SymbolicFile::createSymbolicFile(
80            MemBufferRef, file_magic::bitcode, &Context)) {
81      auto &IRObject = cast<object::IRObjectFile>(**ObjOrErr);
82      auto TargetTriple = Triple(IRObject.getTargetTriple());
83      return TargetTriple.isOSDarwin()
84                 ? object::Archive::K_DARWIN
85                 : (TargetTriple.isOSAIX() ? object::Archive::K_AIXBIG
86                                           : object::Archive::K_GNU);
87    } else {
88      // Squelch the error in case this was not a SymbolicFile.
89      consumeError(ObjOrErr.takeError());
90    }
91  }
92
93  return object::Archive::getDefaultKindForHost();
94}
95
96Expected<NewArchiveMember>
97NewArchiveMember::getOldMember(const object::Archive::Child &OldMember,
98                               bool Deterministic) {
99  Expected<llvm::MemoryBufferRef> BufOrErr = OldMember.getMemoryBufferRef();
100  if (!BufOrErr)
101    return BufOrErr.takeError();
102
103  NewArchiveMember M;
104  M.Buf = MemoryBuffer::getMemBuffer(*BufOrErr, false);
105  M.MemberName = M.Buf->getBufferIdentifier();
106  if (!Deterministic) {
107    auto ModTimeOrErr = OldMember.getLastModified();
108    if (!ModTimeOrErr)
109      return ModTimeOrErr.takeError();
110    M.ModTime = ModTimeOrErr.get();
111    Expected<unsigned> UIDOrErr = OldMember.getUID();
112    if (!UIDOrErr)
113      return UIDOrErr.takeError();
114    M.UID = UIDOrErr.get();
115    Expected<unsigned> GIDOrErr = OldMember.getGID();
116    if (!GIDOrErr)
117      return GIDOrErr.takeError();
118    M.GID = GIDOrErr.get();
119    Expected<sys::fs::perms> AccessModeOrErr = OldMember.getAccessMode();
120    if (!AccessModeOrErr)
121      return AccessModeOrErr.takeError();
122    M.Perms = AccessModeOrErr.get();
123  }
124  return std::move(M);
125}
126
127Expected<NewArchiveMember> NewArchiveMember::getFile(StringRef FileName,
128                                                     bool Deterministic) {
129  sys::fs::file_status Status;
130  auto FDOrErr = sys::fs::openNativeFileForRead(FileName);
131  if (!FDOrErr)
132    return FDOrErr.takeError();
133  sys::fs::file_t FD = *FDOrErr;
134  assert(FD != sys::fs::kInvalidFile);
135
136  if (auto EC = sys::fs::status(FD, Status))
137    return errorCodeToError(EC);
138
139  // Opening a directory doesn't make sense. Let it fail.
140  // Linux cannot open directories with open(2), although
141  // cygwin and *bsd can.
142  if (Status.type() == sys::fs::file_type::directory_file)
143    return errorCodeToError(make_error_code(errc::is_a_directory));
144
145  ErrorOr<std::unique_ptr<MemoryBuffer>> MemberBufferOrErr =
146      MemoryBuffer::getOpenFile(FD, FileName, Status.getSize(), false);
147  if (!MemberBufferOrErr)
148    return errorCodeToError(MemberBufferOrErr.getError());
149
150  if (auto EC = sys::fs::closeFile(FD))
151    return errorCodeToError(EC);
152
153  NewArchiveMember M;
154  M.Buf = std::move(*MemberBufferOrErr);
155  M.MemberName = M.Buf->getBufferIdentifier();
156  if (!Deterministic) {
157    M.ModTime = std::chrono::time_point_cast<std::chrono::seconds>(
158        Status.getLastModificationTime());
159    M.UID = Status.getUser();
160    M.GID = Status.getGroup();
161    M.Perms = Status.permissions();
162  }
163  return std::move(M);
164}
165
166template <typename T>
167static void printWithSpacePadding(raw_ostream &OS, T Data, unsigned Size) {
168  uint64_t OldPos = OS.tell();
169  OS << Data;
170  unsigned SizeSoFar = OS.tell() - OldPos;
171  assert(SizeSoFar <= Size && "Data doesn't fit in Size");
172  OS.indent(Size - SizeSoFar);
173}
174
175static bool isDarwin(object::Archive::Kind Kind) {
176  return Kind == object::Archive::K_DARWIN ||
177         Kind == object::Archive::K_DARWIN64;
178}
179
180static bool isAIXBigArchive(object::Archive::Kind Kind) {
181  return Kind == object::Archive::K_AIXBIG;
182}
183
184static bool isCOFFArchive(object::Archive::Kind Kind) {
185  return Kind == object::Archive::K_COFF;
186}
187
188static bool isBSDLike(object::Archive::Kind Kind) {
189  switch (Kind) {
190  case object::Archive::K_GNU:
191  case object::Archive::K_GNU64:
192  case object::Archive::K_AIXBIG:
193  case object::Archive::K_COFF:
194    return false;
195  case object::Archive::K_BSD:
196  case object::Archive::K_DARWIN:
197  case object::Archive::K_DARWIN64:
198    return true;
199  }
200  llvm_unreachable("not supported for writting");
201}
202
203template <class T>
204static void print(raw_ostream &Out, object::Archive::Kind Kind, T Val) {
205  support::endian::write(Out, Val,
206                         isBSDLike(Kind) ? llvm::endianness::little
207                                         : llvm::endianness::big);
208}
209
210template <class T> static void printLE(raw_ostream &Out, T Val) {
211  support::endian::write(Out, Val, llvm::endianness::little);
212}
213
214static void printRestOfMemberHeader(
215    raw_ostream &Out, const sys::TimePoint<std::chrono::seconds> &ModTime,
216    unsigned UID, unsigned GID, unsigned Perms, uint64_t Size) {
217  printWithSpacePadding(Out, sys::toTimeT(ModTime), 12);
218
219  // The format has only 6 chars for uid and gid. Truncate if the provided
220  // values don't fit.
221  printWithSpacePadding(Out, UID % 1000000, 6);
222  printWithSpacePadding(Out, GID % 1000000, 6);
223
224  printWithSpacePadding(Out, format("%o", Perms), 8);
225  printWithSpacePadding(Out, Size, 10);
226  Out << "`\n";
227}
228
229static void
230printGNUSmallMemberHeader(raw_ostream &Out, StringRef Name,
231                          const sys::TimePoint<std::chrono::seconds> &ModTime,
232                          unsigned UID, unsigned GID, unsigned Perms,
233                          uint64_t Size) {
234  printWithSpacePadding(Out, Twine(Name) + "/", 16);
235  printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
236}
237
238static void
239printBSDMemberHeader(raw_ostream &Out, uint64_t Pos, StringRef Name,
240                     const sys::TimePoint<std::chrono::seconds> &ModTime,
241                     unsigned UID, unsigned GID, unsigned Perms, uint64_t Size) {
242  uint64_t PosAfterHeader = Pos + 60 + Name.size();
243  // Pad so that even 64 bit object files are aligned.
244  unsigned Pad = offsetToAlignment(PosAfterHeader, Align(8));
245  unsigned NameWithPadding = Name.size() + Pad;
246  printWithSpacePadding(Out, Twine("#1/") + Twine(NameWithPadding), 16);
247  printRestOfMemberHeader(Out, ModTime, UID, GID, Perms,
248                          NameWithPadding + Size);
249  Out << Name;
250  while (Pad--)
251    Out.write(uint8_t(0));
252}
253
254static void
255printBigArchiveMemberHeader(raw_ostream &Out, StringRef Name,
256                            const sys::TimePoint<std::chrono::seconds> &ModTime,
257                            unsigned UID, unsigned GID, unsigned Perms,
258                            uint64_t Size, uint64_t PrevOffset,
259                            uint64_t NextOffset) {
260  unsigned NameLen = Name.size();
261
262  printWithSpacePadding(Out, Size, 20);           // File member size
263  printWithSpacePadding(Out, NextOffset, 20);     // Next member header offset
264  printWithSpacePadding(Out, PrevOffset, 20); // Previous member header offset
265  printWithSpacePadding(Out, sys::toTimeT(ModTime), 12); // File member date
266  // The big archive format has 12 chars for uid and gid.
267  printWithSpacePadding(Out, UID % 1000000000000, 12);   // UID
268  printWithSpacePadding(Out, GID % 1000000000000, 12);   // GID
269  printWithSpacePadding(Out, format("%o", Perms), 12);   // Permission
270  printWithSpacePadding(Out, NameLen, 4);                // Name length
271  if (NameLen) {
272    printWithSpacePadding(Out, Name, NameLen); // Name
273    if (NameLen % 2)
274      Out.write(uint8_t(0)); // Null byte padding
275  }
276  Out << "`\n"; // Terminator
277}
278
279static bool useStringTable(bool Thin, StringRef Name) {
280  return Thin || Name.size() >= 16 || Name.contains('/');
281}
282
283static bool is64BitKind(object::Archive::Kind Kind) {
284  switch (Kind) {
285  case object::Archive::K_GNU:
286  case object::Archive::K_BSD:
287  case object::Archive::K_DARWIN:
288  case object::Archive::K_COFF:
289    return false;
290  case object::Archive::K_AIXBIG:
291  case object::Archive::K_DARWIN64:
292  case object::Archive::K_GNU64:
293    return true;
294  }
295  llvm_unreachable("not supported for writting");
296}
297
298static void
299printMemberHeader(raw_ostream &Out, uint64_t Pos, raw_ostream &StringTable,
300                  StringMap<uint64_t> &MemberNames, object::Archive::Kind Kind,
301                  bool Thin, const NewArchiveMember &M,
302                  sys::TimePoint<std::chrono::seconds> ModTime, uint64_t Size) {
303  if (isBSDLike(Kind))
304    return printBSDMemberHeader(Out, Pos, M.MemberName, ModTime, M.UID, M.GID,
305                                M.Perms, Size);
306  if (!useStringTable(Thin, M.MemberName))
307    return printGNUSmallMemberHeader(Out, M.MemberName, ModTime, M.UID, M.GID,
308                                     M.Perms, Size);
309  Out << '/';
310  uint64_t NamePos;
311  if (Thin) {
312    NamePos = StringTable.tell();
313    StringTable << M.MemberName << "/\n";
314  } else {
315    auto Insertion = MemberNames.insert({M.MemberName, uint64_t(0)});
316    if (Insertion.second) {
317      Insertion.first->second = StringTable.tell();
318      StringTable << M.MemberName;
319      if (isCOFFArchive(Kind))
320        StringTable << '\0';
321      else
322        StringTable << "/\n";
323    }
324    NamePos = Insertion.first->second;
325  }
326  printWithSpacePadding(Out, NamePos, 15);
327  printRestOfMemberHeader(Out, ModTime, M.UID, M.GID, M.Perms, Size);
328}
329
330namespace {
331struct MemberData {
332  std::vector<unsigned> Symbols;
333  std::string Header;
334  StringRef Data;
335  StringRef Padding;
336  uint64_t PreHeadPadSize = 0;
337  std::unique_ptr<SymbolicFile> SymFile = nullptr;
338};
339} // namespace
340
341static MemberData computeStringTable(StringRef Names) {
342  unsigned Size = Names.size();
343  unsigned Pad = offsetToAlignment(Size, Align(2));
344  std::string Header;
345  raw_string_ostream Out(Header);
346  printWithSpacePadding(Out, "//", 48);
347  printWithSpacePadding(Out, Size + Pad, 10);
348  Out << "`\n";
349  Out.flush();
350  return {{}, std::move(Header), Names, Pad ? "\n" : ""};
351}
352
353static sys::TimePoint<std::chrono::seconds> now(bool Deterministic) {
354  using namespace std::chrono;
355
356  if (!Deterministic)
357    return time_point_cast<seconds>(system_clock::now());
358  return sys::TimePoint<seconds>();
359}
360
361static bool isArchiveSymbol(const object::BasicSymbolRef &S) {
362  Expected<uint32_t> SymFlagsOrErr = S.getFlags();
363  if (!SymFlagsOrErr)
364    // TODO: Actually report errors helpfully.
365    report_fatal_error(SymFlagsOrErr.takeError());
366  if (*SymFlagsOrErr & object::SymbolRef::SF_FormatSpecific)
367    return false;
368  if (!(*SymFlagsOrErr & object::SymbolRef::SF_Global))
369    return false;
370  if (*SymFlagsOrErr & object::SymbolRef::SF_Undefined)
371    return false;
372  return true;
373}
374
375static void printNBits(raw_ostream &Out, object::Archive::Kind Kind,
376                       uint64_t Val) {
377  if (is64BitKind(Kind))
378    print<uint64_t>(Out, Kind, Val);
379  else
380    print<uint32_t>(Out, Kind, Val);
381}
382
383static uint64_t computeSymbolTableSize(object::Archive::Kind Kind,
384                                       uint64_t NumSyms, uint64_t OffsetSize,
385                                       uint64_t StringTableSize,
386                                       uint32_t *Padding = nullptr) {
387  assert((OffsetSize == 4 || OffsetSize == 8) && "Unsupported OffsetSize");
388  uint64_t Size = OffsetSize; // Number of entries
389  if (isBSDLike(Kind))
390    Size += NumSyms * OffsetSize * 2; // Table
391  else
392    Size += NumSyms * OffsetSize; // Table
393  if (isBSDLike(Kind))
394    Size += OffsetSize; // byte count
395  Size += StringTableSize;
396  // ld64 expects the members to be 8-byte aligned for 64-bit content and at
397  // least 4-byte aligned for 32-bit content.  Opt for the larger encoding
398  // uniformly.
399  // We do this for all bsd formats because it simplifies aligning members.
400  // For the big archive format, the symbol table is the last member, so there
401  // is no need to align.
402  uint32_t Pad = isAIXBigArchive(Kind)
403                     ? 0
404                     : offsetToAlignment(Size, Align(isBSDLike(Kind) ? 8 : 2));
405
406  Size += Pad;
407  if (Padding)
408    *Padding = Pad;
409  return Size;
410}
411
412static uint64_t computeSymbolMapSize(uint64_t NumObj, SymMap &SymMap,
413                                     uint32_t *Padding = nullptr) {
414  uint64_t Size = sizeof(uint32_t) * 2; // Number of symbols and objects entries
415  Size += NumObj * sizeof(uint32_t);    // Offset table
416
417  for (auto S : SymMap.Map)
418    Size += sizeof(uint16_t) + S.first.length() + 1;
419
420  uint32_t Pad = offsetToAlignment(Size, Align(2));
421  Size += Pad;
422  if (Padding)
423    *Padding = Pad;
424  return Size;
425}
426
427static uint64_t computeECSymbolsSize(SymMap &SymMap,
428                                     uint32_t *Padding = nullptr) {
429  uint64_t Size = sizeof(uint32_t); // Number of symbols
430
431  for (auto S : SymMap.ECMap)
432    Size += sizeof(uint16_t) + S.first.length() + 1;
433
434  uint32_t Pad = offsetToAlignment(Size, Align(2));
435  Size += Pad;
436  if (Padding)
437    *Padding = Pad;
438  return Size;
439}
440
441static void writeSymbolTableHeader(raw_ostream &Out, object::Archive::Kind Kind,
442                                   bool Deterministic, uint64_t Size,
443                                   uint64_t PrevMemberOffset = 0,
444                                   uint64_t NextMemberOffset = 0) {
445  if (isBSDLike(Kind)) {
446    const char *Name = is64BitKind(Kind) ? "__.SYMDEF_64" : "__.SYMDEF";
447    printBSDMemberHeader(Out, Out.tell(), Name, now(Deterministic), 0, 0, 0,
448                         Size);
449  } else if (isAIXBigArchive(Kind)) {
450    printBigArchiveMemberHeader(Out, "", now(Deterministic), 0, 0, 0, Size,
451                                PrevMemberOffset, NextMemberOffset);
452  } else {
453    const char *Name = is64BitKind(Kind) ? "/SYM64" : "";
454    printGNUSmallMemberHeader(Out, Name, now(Deterministic), 0, 0, 0, Size);
455  }
456}
457
458static uint64_t computeHeadersSize(object::Archive::Kind Kind,
459                                   uint64_t NumMembers,
460                                   uint64_t StringMemberSize, uint64_t NumSyms,
461                                   uint64_t SymNamesSize, SymMap *SymMap) {
462  uint32_t OffsetSize = is64BitKind(Kind) ? 8 : 4;
463  uint64_t SymtabSize =
464      computeSymbolTableSize(Kind, NumSyms, OffsetSize, SymNamesSize);
465  auto computeSymbolTableHeaderSize = [=] {
466    SmallString<0> TmpBuf;
467    raw_svector_ostream Tmp(TmpBuf);
468    writeSymbolTableHeader(Tmp, Kind, true, SymtabSize);
469    return TmpBuf.size();
470  };
471  uint32_t HeaderSize = computeSymbolTableHeaderSize();
472  uint64_t Size = strlen("!<arch>\n") + HeaderSize + SymtabSize;
473
474  if (SymMap) {
475    Size += HeaderSize + computeSymbolMapSize(NumMembers, *SymMap);
476    if (SymMap->ECMap.size())
477      Size += HeaderSize + computeECSymbolsSize(*SymMap);
478  }
479
480  return Size + StringMemberSize;
481}
482
483static Expected<std::unique_ptr<SymbolicFile>>
484getSymbolicFile(MemoryBufferRef Buf, LLVMContext &Context) {
485  const file_magic Type = identify_magic(Buf.getBuffer());
486  // Don't attempt to read non-symbolic file types.
487  if (!object::SymbolicFile::isSymbolicFile(Type, &Context))
488    return nullptr;
489  if (Type == file_magic::bitcode) {
490    auto ObjOrErr = object::SymbolicFile::createSymbolicFile(
491        Buf, file_magic::bitcode, &Context);
492    if (!ObjOrErr)
493      return ObjOrErr.takeError();
494    return std::move(*ObjOrErr);
495  } else {
496    auto ObjOrErr = object::SymbolicFile::createSymbolicFile(Buf);
497    if (!ObjOrErr)
498      return ObjOrErr.takeError();
499    return std::move(*ObjOrErr);
500  }
501}
502
503static bool is64BitSymbolicFile(const SymbolicFile *SymObj) {
504  return SymObj != nullptr ? SymObj->is64Bit() : false;
505}
506
507// Log2 of PAGESIZE(4096) on an AIX system.
508static const uint32_t Log2OfAIXPageSize = 12;
509
510// In the AIX big archive format, since the data content follows the member file
511// name, if the name ends on an odd byte, an extra byte will be added for
512// padding. This ensures that the data within the member file starts at an even
513// byte.
514static const uint32_t MinBigArchiveMemDataAlign = 2;
515
516template <typename AuxiliaryHeader>
517uint16_t getAuxMaxAlignment(uint16_t AuxHeaderSize, AuxiliaryHeader *AuxHeader,
518                            uint16_t Log2OfMaxAlign) {
519  // If the member doesn't have an auxiliary header, it isn't a loadable object
520  // and so it just needs aligning at the minimum value.
521  if (AuxHeader == nullptr)
522    return MinBigArchiveMemDataAlign;
523
524  // If the auxiliary header does not have both MaxAlignOfData and
525  // MaxAlignOfText field, it is not a loadable shared object file, so align at
526  // the minimum value. The 'ModuleType' member is located right after
527  // 'MaxAlignOfData' in the AuxiliaryHeader.
528  if (AuxHeaderSize < offsetof(AuxiliaryHeader, ModuleType))
529    return MinBigArchiveMemDataAlign;
530
531  // If the XCOFF object file does not have a loader section, it is not
532  // loadable, so align at the minimum value.
533  if (AuxHeader->SecNumOfLoader == 0)
534    return MinBigArchiveMemDataAlign;
535
536  // The content of the loadable member file needs to be aligned at MAX(maximum
537  // alignment of .text, maximum alignment of .data) if there are both fields.
538  // If the desired alignment is > PAGESIZE, 32-bit members are aligned on a
539  // word boundary, while 64-bit members are aligned on a PAGESIZE(2^12=4096)
540  // boundary.
541  uint16_t Log2OfAlign =
542      std::max(AuxHeader->MaxAlignOfText, AuxHeader->MaxAlignOfData);
543  return 1 << (Log2OfAlign > Log2OfAIXPageSize ? Log2OfMaxAlign : Log2OfAlign);
544}
545
546// AIX big archives may contain shared object members. The AIX OS requires these
547// members to be aligned if they are 64-bit and recommends it for 32-bit
548// members. This ensures that when these members are loaded they are aligned in
549// memory.
550static uint32_t getMemberAlignment(SymbolicFile *SymObj) {
551  XCOFFObjectFile *XCOFFObj = dyn_cast_or_null<XCOFFObjectFile>(SymObj);
552  if (!XCOFFObj)
553    return MinBigArchiveMemDataAlign;
554
555  // If the desired alignment is > PAGESIZE, 32-bit members are aligned on a
556  // word boundary, while 64-bit members are aligned on a PAGESIZE boundary.
557  return XCOFFObj->is64Bit()
558             ? getAuxMaxAlignment(XCOFFObj->fileHeader64()->AuxHeaderSize,
559                                  XCOFFObj->auxiliaryHeader64(),
560                                  Log2OfAIXPageSize)
561             : getAuxMaxAlignment(XCOFFObj->fileHeader32()->AuxHeaderSize,
562                                  XCOFFObj->auxiliaryHeader32(), 2);
563}
564
565static void writeSymbolTable(raw_ostream &Out, object::Archive::Kind Kind,
566                             bool Deterministic, ArrayRef<MemberData> Members,
567                             StringRef StringTable, uint64_t MembersOffset,
568                             unsigned NumSyms, uint64_t PrevMemberOffset = 0,
569                             uint64_t NextMemberOffset = 0,
570                             bool Is64Bit = false) {
571  // We don't write a symbol table on an archive with no members -- except on
572  // Darwin, where the linker will abort unless the archive has a symbol table.
573  if (StringTable.empty() && !isDarwin(Kind) && !isCOFFArchive(Kind))
574    return;
575
576  uint64_t OffsetSize = is64BitKind(Kind) ? 8 : 4;
577  uint32_t Pad;
578  uint64_t Size = computeSymbolTableSize(Kind, NumSyms, OffsetSize,
579                                         StringTable.size(), &Pad);
580  writeSymbolTableHeader(Out, Kind, Deterministic, Size, PrevMemberOffset,
581                         NextMemberOffset);
582
583  if (isBSDLike(Kind))
584    printNBits(Out, Kind, NumSyms * 2 * OffsetSize);
585  else
586    printNBits(Out, Kind, NumSyms);
587
588  uint64_t Pos = MembersOffset;
589  for (const MemberData &M : Members) {
590    if (isAIXBigArchive(Kind)) {
591      Pos += M.PreHeadPadSize;
592      if (is64BitSymbolicFile(M.SymFile.get()) != Is64Bit) {
593        Pos += M.Header.size() + M.Data.size() + M.Padding.size();
594        continue;
595      }
596    }
597
598    for (unsigned StringOffset : M.Symbols) {
599      if (isBSDLike(Kind))
600        printNBits(Out, Kind, StringOffset);
601      printNBits(Out, Kind, Pos); // member offset
602    }
603    Pos += M.Header.size() + M.Data.size() + M.Padding.size();
604  }
605
606  if (isBSDLike(Kind))
607    // byte count of the string table
608    printNBits(Out, Kind, StringTable.size());
609  Out << StringTable;
610
611  while (Pad--)
612    Out.write(uint8_t(0));
613}
614
615static void writeSymbolMap(raw_ostream &Out, object::Archive::Kind Kind,
616                           bool Deterministic, ArrayRef<MemberData> Members,
617                           SymMap &SymMap, uint64_t MembersOffset) {
618  uint32_t Pad;
619  uint64_t Size = computeSymbolMapSize(Members.size(), SymMap, &Pad);
620  writeSymbolTableHeader(Out, Kind, Deterministic, Size, 0);
621
622  uint32_t Pos = MembersOffset;
623
624  printLE<uint32_t>(Out, Members.size());
625  for (const MemberData &M : Members) {
626    printLE(Out, Pos); // member offset
627    Pos += M.Header.size() + M.Data.size() + M.Padding.size();
628  }
629
630  printLE<uint32_t>(Out, SymMap.Map.size());
631
632  for (auto S : SymMap.Map)
633    printLE(Out, S.second);
634  for (auto S : SymMap.Map)
635    Out << S.first << '\0';
636
637  while (Pad--)
638    Out.write(uint8_t(0));
639}
640
641static void writeECSymbols(raw_ostream &Out, object::Archive::Kind Kind,
642                           bool Deterministic, ArrayRef<MemberData> Members,
643                           SymMap &SymMap) {
644  uint32_t Pad;
645  uint64_t Size = computeECSymbolsSize(SymMap, &Pad);
646  printGNUSmallMemberHeader(Out, "/<ECSYMBOLS>", now(Deterministic), 0, 0, 0,
647                            Size);
648
649  printLE<uint32_t>(Out, SymMap.ECMap.size());
650
651  for (auto S : SymMap.ECMap)
652    printLE(Out, S.second);
653  for (auto S : SymMap.ECMap)
654    Out << S.first << '\0';
655  while (Pad--)
656    Out.write(uint8_t(0));
657}
658
659static bool isECObject(object::SymbolicFile &Obj) {
660  if (Obj.isCOFF())
661    return cast<llvm::object::COFFObjectFile>(&Obj)->getMachine() !=
662           COFF::IMAGE_FILE_MACHINE_ARM64;
663
664  if (Obj.isCOFFImportFile())
665    return cast<llvm::object::COFFImportFile>(&Obj)->getMachine() !=
666           COFF::IMAGE_FILE_MACHINE_ARM64;
667
668  if (Obj.isIR()) {
669    Expected<std::string> TripleStr =
670        getBitcodeTargetTriple(Obj.getMemoryBufferRef());
671    if (!TripleStr)
672      return false;
673    Triple T(*TripleStr);
674    return T.isWindowsArm64EC() || T.getArch() == Triple::x86_64;
675  }
676
677  return false;
678}
679
680bool isImportDescriptor(StringRef Name) {
681  return Name.starts_with(ImportDescriptorPrefix) ||
682         Name == StringRef{NullImportDescriptorSymbolName} ||
683         (Name.starts_with(NullThunkDataPrefix) &&
684          Name.ends_with(NullThunkDataSuffix));
685}
686
687static Expected<std::vector<unsigned>> getSymbols(SymbolicFile *Obj,
688                                                  uint16_t Index,
689                                                  raw_ostream &SymNames,
690                                                  SymMap *SymMap) {
691  std::vector<unsigned> Ret;
692
693  if (Obj == nullptr)
694    return Ret;
695
696  std::map<std::string, uint16_t> *Map = nullptr;
697  if (SymMap)
698    Map = SymMap->UseECMap && isECObject(*Obj) ? &SymMap->ECMap : &SymMap->Map;
699
700  for (const object::BasicSymbolRef &S : Obj->symbols()) {
701    if (!isArchiveSymbol(S))
702      continue;
703    if (Map) {
704      std::string Name;
705      raw_string_ostream NameStream(Name);
706      if (Error E = S.printName(NameStream))
707        return std::move(E);
708      if (Map->find(Name) != Map->end())
709        continue; // ignore duplicated symbol
710      (*Map)[Name] = Index;
711      if (Map == &SymMap->Map) {
712        Ret.push_back(SymNames.tell());
713        SymNames << Name << '\0';
714        // If EC is enabled, then the import descriptors are NOT put into EC
715        // objects so we need to copy them to the EC map manually.
716        if (SymMap->UseECMap && isImportDescriptor(Name))
717          SymMap->ECMap[Name] = Index;
718      }
719    } else {
720      Ret.push_back(SymNames.tell());
721      if (Error E = S.printName(SymNames))
722        return std::move(E);
723      SymNames << '\0';
724    }
725  }
726  return Ret;
727}
728
729static Expected<std::vector<MemberData>>
730computeMemberData(raw_ostream &StringTable, raw_ostream &SymNames,
731                  object::Archive::Kind Kind, bool Thin, bool Deterministic,
732                  SymtabWritingMode NeedSymbols, SymMap *SymMap,
733                  LLVMContext &Context, ArrayRef<NewArchiveMember> NewMembers) {
734  static char PaddingData[8] = {'\n', '\n', '\n', '\n', '\n', '\n', '\n', '\n'};
735  uint64_t MemHeadPadSize = 0;
736  uint64_t Pos =
737      isAIXBigArchive(Kind) ? sizeof(object::BigArchive::FixLenHdr) : 0;
738
739  std::vector<MemberData> Ret;
740  bool HasObject = false;
741
742  // Deduplicate long member names in the string table and reuse earlier name
743  // offsets. This especially saves space for COFF Import libraries where all
744  // members have the same name.
745  StringMap<uint64_t> MemberNames;
746
747  // UniqueTimestamps is a special case to improve debugging on Darwin:
748  //
749  // The Darwin linker does not link debug info into the final
750  // binary. Instead, it emits entries of type N_OSO in the output
751  // binary's symbol table, containing references to the linked-in
752  // object files. Using that reference, the debugger can read the
753  // debug data directly from the object files. Alternatively, an
754  // invocation of 'dsymutil' will link the debug data from the object
755  // files into a dSYM bundle, which can be loaded by the debugger,
756  // instead of the object files.
757  //
758  // For an object file, the N_OSO entries contain the absolute path
759  // path to the file, and the file's timestamp. For an object
760  // included in an archive, the path is formatted like
761  // "/absolute/path/to/archive.a(member.o)", and the timestamp is the
762  // archive member's timestamp, rather than the archive's timestamp.
763  //
764  // However, this doesn't always uniquely identify an object within
765  // an archive -- an archive file can have multiple entries with the
766  // same filename. (This will happen commonly if the original object
767  // files started in different directories.) The only way they get
768  // distinguished, then, is via the timestamp. But this process is
769  // unable to find the correct object file in the archive when there
770  // are two files of the same name and timestamp.
771  //
772  // Additionally, timestamp==0 is treated specially, and causes the
773  // timestamp to be ignored as a match criteria.
774  //
775  // That will "usually" work out okay when creating an archive not in
776  // deterministic timestamp mode, because the objects will probably
777  // have been created at different timestamps.
778  //
779  // To ameliorate this problem, in deterministic archive mode (which
780  // is the default), on Darwin we will emit a unique non-zero
781  // timestamp for each entry with a duplicated name. This is still
782  // deterministic: the only thing affecting that timestamp is the
783  // order of the files in the resultant archive.
784  //
785  // See also the functions that handle the lookup:
786  // in lldb: ObjectContainerBSDArchive::Archive::FindObject()
787  // in llvm/tools/dsymutil: BinaryHolder::GetArchiveMemberBuffers().
788  bool UniqueTimestamps = Deterministic && isDarwin(Kind);
789  std::map<StringRef, unsigned> FilenameCount;
790  if (UniqueTimestamps) {
791    for (const NewArchiveMember &M : NewMembers)
792      FilenameCount[M.MemberName]++;
793    for (auto &Entry : FilenameCount)
794      Entry.second = Entry.second > 1 ? 1 : 0;
795  }
796
797  // The big archive format needs to know the offset of the previous member
798  // header.
799  uint64_t PrevOffset = 0;
800  uint64_t NextMemHeadPadSize = 0;
801  std::unique_ptr<SymbolicFile> CurSymFile;
802  std::unique_ptr<SymbolicFile> NextSymFile;
803  uint16_t Index = 0;
804
805  for (auto M = NewMembers.begin(); M < NewMembers.end(); ++M) {
806    std::string Header;
807    raw_string_ostream Out(Header);
808
809    MemoryBufferRef Buf = M->Buf->getMemBufferRef();
810    StringRef Data = Thin ? "" : Buf.getBuffer();
811
812    Index++;
813
814    // ld64 expects the members to be 8-byte aligned for 64-bit content and at
815    // least 4-byte aligned for 32-bit content.  Opt for the larger encoding
816    // uniformly.  This matches the behaviour with cctools and ensures that ld64
817    // is happy with archives that we generate.
818    unsigned MemberPadding =
819        isDarwin(Kind) ? offsetToAlignment(Data.size(), Align(8)) : 0;
820    unsigned TailPadding =
821        offsetToAlignment(Data.size() + MemberPadding, Align(2));
822    StringRef Padding = StringRef(PaddingData, MemberPadding + TailPadding);
823
824    sys::TimePoint<std::chrono::seconds> ModTime;
825    if (UniqueTimestamps)
826      // Increment timestamp for each file of a given name.
827      ModTime = sys::toTimePoint(FilenameCount[M->MemberName]++);
828    else
829      ModTime = M->ModTime;
830
831    uint64_t Size = Buf.getBufferSize() + MemberPadding;
832    if (Size > object::Archive::MaxMemberSize) {
833      std::string StringMsg =
834          "File " + M->MemberName.str() + " exceeds size limit";
835      return make_error<object::GenericBinaryError>(
836          std::move(StringMsg), object::object_error::parse_failed);
837    }
838
839    if (NeedSymbols != SymtabWritingMode::NoSymtab || isAIXBigArchive(Kind)) {
840      auto SetNextSymFile = [&NextSymFile,
841                             &Context](MemoryBufferRef Buf,
842                                       StringRef MemberName) -> Error {
843        Expected<std::unique_ptr<SymbolicFile>> SymFileOrErr =
844            getSymbolicFile(Buf, Context);
845        if (!SymFileOrErr)
846          return createFileError(MemberName, SymFileOrErr.takeError());
847        NextSymFile = std::move(*SymFileOrErr);
848        return Error::success();
849      };
850
851      if (M == NewMembers.begin())
852        if (Error Err = SetNextSymFile(Buf, M->MemberName))
853          return std::move(Err);
854
855      CurSymFile = std::move(NextSymFile);
856
857      if ((M + 1) != NewMembers.end())
858        if (Error Err = SetNextSymFile((M + 1)->Buf->getMemBufferRef(),
859                                       (M + 1)->MemberName))
860          return std::move(Err);
861    }
862
863    // In the big archive file format, we need to calculate and include the next
864    // member offset and previous member offset in the file member header.
865    if (isAIXBigArchive(Kind)) {
866      uint64_t OffsetToMemData = Pos + sizeof(object::BigArMemHdrType) +
867                                 alignTo(M->MemberName.size(), 2);
868
869      if (M == NewMembers.begin())
870        NextMemHeadPadSize =
871            alignToPowerOf2(OffsetToMemData,
872                            getMemberAlignment(CurSymFile.get())) -
873            OffsetToMemData;
874
875      MemHeadPadSize = NextMemHeadPadSize;
876      Pos += MemHeadPadSize;
877      uint64_t NextOffset = Pos + sizeof(object::BigArMemHdrType) +
878                            alignTo(M->MemberName.size(), 2) + alignTo(Size, 2);
879
880      // If there is another member file after this, we need to calculate the
881      // padding before the header.
882      if ((M + 1) != NewMembers.end()) {
883        uint64_t OffsetToNextMemData = NextOffset +
884                                       sizeof(object::BigArMemHdrType) +
885                                       alignTo((M + 1)->MemberName.size(), 2);
886        NextMemHeadPadSize =
887            alignToPowerOf2(OffsetToNextMemData,
888                            getMemberAlignment(NextSymFile.get())) -
889            OffsetToNextMemData;
890        NextOffset += NextMemHeadPadSize;
891      }
892      printBigArchiveMemberHeader(Out, M->MemberName, ModTime, M->UID, M->GID,
893                                  M->Perms, Size, PrevOffset, NextOffset);
894      PrevOffset = Pos;
895    } else {
896      printMemberHeader(Out, Pos, StringTable, MemberNames, Kind, Thin, *M,
897                        ModTime, Size);
898    }
899    Out.flush();
900
901    std::vector<unsigned> Symbols;
902    if (NeedSymbols != SymtabWritingMode::NoSymtab) {
903      Expected<std::vector<unsigned>> SymbolsOrErr =
904          getSymbols(CurSymFile.get(), Index, SymNames, SymMap);
905      if (!SymbolsOrErr)
906        return createFileError(M->MemberName, SymbolsOrErr.takeError());
907      Symbols = std::move(*SymbolsOrErr);
908      if (CurSymFile)
909        HasObject = true;
910    }
911
912    Pos += Header.size() + Data.size() + Padding.size();
913    Ret.push_back({std::move(Symbols), std::move(Header), Data, Padding,
914                   MemHeadPadSize, std::move(CurSymFile)});
915  }
916  // If there are no symbols, emit an empty symbol table, to satisfy Solaris
917  // tools, older versions of which expect a symbol table in a non-empty
918  // archive, regardless of whether there are any symbols in it.
919  if (HasObject && SymNames.tell() == 0 && !isCOFFArchive(Kind))
920    SymNames << '\0' << '\0' << '\0';
921  return std::move(Ret);
922}
923
924namespace llvm {
925
926static ErrorOr<SmallString<128>> canonicalizePath(StringRef P) {
927  SmallString<128> Ret = P;
928  std::error_code Err = sys::fs::make_absolute(Ret);
929  if (Err)
930    return Err;
931  sys::path::remove_dots(Ret, /*removedotdot*/ true);
932  return Ret;
933}
934
935// Compute the relative path from From to To.
936Expected<std::string> computeArchiveRelativePath(StringRef From, StringRef To) {
937  ErrorOr<SmallString<128>> PathToOrErr = canonicalizePath(To);
938  ErrorOr<SmallString<128>> DirFromOrErr = canonicalizePath(From);
939  if (!PathToOrErr || !DirFromOrErr)
940    return errorCodeToError(std::error_code(errno, std::generic_category()));
941
942  const SmallString<128> &PathTo = *PathToOrErr;
943  const SmallString<128> &DirFrom = sys::path::parent_path(*DirFromOrErr);
944
945  // Can't construct a relative path between different roots
946  if (sys::path::root_name(PathTo) != sys::path::root_name(DirFrom))
947    return sys::path::convert_to_slash(PathTo);
948
949  // Skip common prefixes
950  auto FromTo =
951      std::mismatch(sys::path::begin(DirFrom), sys::path::end(DirFrom),
952                    sys::path::begin(PathTo));
953  auto FromI = FromTo.first;
954  auto ToI = FromTo.second;
955
956  // Construct relative path
957  SmallString<128> Relative;
958  for (auto FromE = sys::path::end(DirFrom); FromI != FromE; ++FromI)
959    sys::path::append(Relative, sys::path::Style::posix, "..");
960
961  for (auto ToE = sys::path::end(PathTo); ToI != ToE; ++ToI)
962    sys::path::append(Relative, sys::path::Style::posix, *ToI);
963
964  return std::string(Relative);
965}
966
967static Error writeArchiveToStream(raw_ostream &Out,
968                                  ArrayRef<NewArchiveMember> NewMembers,
969                                  SymtabWritingMode WriteSymtab,
970                                  object::Archive::Kind Kind,
971                                  bool Deterministic, bool Thin, bool IsEC) {
972  assert((!Thin || !isBSDLike(Kind)) && "Only the gnu format has a thin mode");
973
974  SmallString<0> SymNamesBuf;
975  raw_svector_ostream SymNames(SymNamesBuf);
976  SmallString<0> StringTableBuf;
977  raw_svector_ostream StringTable(StringTableBuf);
978  SymMap SymMap;
979
980  // COFF symbol map uses 16-bit indexes, so we can't use it if there are too
981  // many members.
982  if (isCOFFArchive(Kind) && NewMembers.size() > 0xfffe)
983    Kind = object::Archive::K_GNU;
984
985  // In the scenario when LLVMContext is populated SymbolicFile will contain a
986  // reference to it, thus SymbolicFile should be destroyed first.
987  LLVMContext Context;
988
989  SymMap.UseECMap = IsEC;
990  Expected<std::vector<MemberData>> DataOrErr = computeMemberData(
991      StringTable, SymNames, Kind, Thin, Deterministic, WriteSymtab,
992      isCOFFArchive(Kind) ? &SymMap : nullptr, Context, NewMembers);
993  if (Error E = DataOrErr.takeError())
994    return E;
995  std::vector<MemberData> &Data = *DataOrErr;
996
997  uint64_t StringTableSize = 0;
998  MemberData StringTableMember;
999  if (!StringTableBuf.empty() && !isAIXBigArchive(Kind)) {
1000    StringTableMember = computeStringTable(StringTableBuf);
1001    StringTableSize = StringTableMember.Header.size() +
1002                      StringTableMember.Data.size() +
1003                      StringTableMember.Padding.size();
1004  }
1005
1006  // We would like to detect if we need to switch to a 64-bit symbol table.
1007  uint64_t LastMemberEndOffset = 0;
1008  uint64_t LastMemberHeaderOffset = 0;
1009  uint64_t NumSyms = 0;
1010  uint64_t NumSyms32 = 0; // Store symbol number of 32-bit member files.
1011  bool ShouldWriteSymtab = WriteSymtab != SymtabWritingMode::NoSymtab;
1012
1013  for (const auto &M : Data) {
1014    // Record the start of the member's offset
1015    LastMemberEndOffset += M.PreHeadPadSize;
1016    LastMemberHeaderOffset = LastMemberEndOffset;
1017    // Account for the size of each part associated with the member.
1018    LastMemberEndOffset += M.Header.size() + M.Data.size() + M.Padding.size();
1019    NumSyms += M.Symbols.size();
1020
1021    // AIX big archive files may contain two global symbol tables. The
1022    // first global symbol table locates 32-bit file members that define global
1023    // symbols; the second global symbol table does the same for 64-bit file
1024    // members. As a big archive can have both 32-bit and 64-bit file members,
1025    // we need to know the number of symbols in each symbol table individually.
1026    if (isAIXBigArchive(Kind) && ShouldWriteSymtab) {
1027        if (!is64BitSymbolicFile(M.SymFile.get()))
1028          NumSyms32 += M.Symbols.size();
1029      }
1030  }
1031
1032  std::optional<uint64_t> HeadersSize;
1033
1034  // The symbol table is put at the end of the big archive file. The symbol
1035  // table is at the start of the archive file for other archive formats.
1036  if (ShouldWriteSymtab && !is64BitKind(Kind)) {
1037    // We assume 32-bit offsets to see if 32-bit symbols are possible or not.
1038    HeadersSize = computeHeadersSize(Kind, Data.size(), StringTableSize,
1039                                     NumSyms, SymNamesBuf.size(),
1040                                     isCOFFArchive(Kind) ? &SymMap : nullptr);
1041
1042    // The SYM64 format is used when an archive's member offsets are larger than
1043    // 32-bits can hold. The need for this shift in format is detected by
1044    // writeArchive. To test this we need to generate a file with a member that
1045    // has an offset larger than 32-bits but this demands a very slow test. To
1046    // speed the test up we use this environment variable to pretend like the
1047    // cutoff happens before 32-bits and instead happens at some much smaller
1048    // value.
1049    uint64_t Sym64Threshold = 1ULL << 32;
1050    const char *Sym64Env = std::getenv("SYM64_THRESHOLD");
1051    if (Sym64Env)
1052      StringRef(Sym64Env).getAsInteger(10, Sym64Threshold);
1053
1054    // If LastMemberHeaderOffset isn't going to fit in a 32-bit varible we need
1055    // to switch to 64-bit. Note that the file can be larger than 4GB as long as
1056    // the last member starts before the 4GB offset.
1057    if (*HeadersSize + LastMemberHeaderOffset >= Sym64Threshold) {
1058      if (Kind == object::Archive::K_DARWIN)
1059        Kind = object::Archive::K_DARWIN64;
1060      else
1061        Kind = object::Archive::K_GNU64;
1062      HeadersSize.reset();
1063    }
1064  }
1065
1066  if (Thin)
1067    Out << "!<thin>\n";
1068  else if (isAIXBigArchive(Kind))
1069    Out << "<bigaf>\n";
1070  else
1071    Out << "!<arch>\n";
1072
1073  if (!isAIXBigArchive(Kind)) {
1074    if (ShouldWriteSymtab) {
1075      if (!HeadersSize)
1076        HeadersSize = computeHeadersSize(
1077            Kind, Data.size(), StringTableSize, NumSyms, SymNamesBuf.size(),
1078            isCOFFArchive(Kind) ? &SymMap : nullptr);
1079      writeSymbolTable(Out, Kind, Deterministic, Data, SymNamesBuf,
1080                       *HeadersSize, NumSyms);
1081
1082      if (isCOFFArchive(Kind))
1083        writeSymbolMap(Out, Kind, Deterministic, Data, SymMap, *HeadersSize);
1084    }
1085
1086    if (StringTableSize)
1087      Out << StringTableMember.Header << StringTableMember.Data
1088          << StringTableMember.Padding;
1089
1090    if (ShouldWriteSymtab && SymMap.ECMap.size())
1091      writeECSymbols(Out, Kind, Deterministic, Data, SymMap);
1092
1093    for (const MemberData &M : Data)
1094      Out << M.Header << M.Data << M.Padding;
1095  } else {
1096    HeadersSize = sizeof(object::BigArchive::FixLenHdr);
1097    LastMemberEndOffset += *HeadersSize;
1098    LastMemberHeaderOffset += *HeadersSize;
1099
1100    // For the big archive (AIX) format, compute a table of member names and
1101    // offsets, used in the member table.
1102    uint64_t MemberTableNameStrTblSize = 0;
1103    std::vector<size_t> MemberOffsets;
1104    std::vector<StringRef> MemberNames;
1105    // Loop across object to find offset and names.
1106    uint64_t MemberEndOffset = sizeof(object::BigArchive::FixLenHdr);
1107    for (size_t I = 0, Size = NewMembers.size(); I != Size; ++I) {
1108      const NewArchiveMember &Member = NewMembers[I];
1109      MemberTableNameStrTblSize += Member.MemberName.size() + 1;
1110      MemberEndOffset += Data[I].PreHeadPadSize;
1111      MemberOffsets.push_back(MemberEndOffset);
1112      MemberNames.push_back(Member.MemberName);
1113      // File member name ended with "`\n". The length is included in
1114      // BigArMemHdrType.
1115      MemberEndOffset += sizeof(object::BigArMemHdrType) +
1116                         alignTo(Data[I].Data.size(), 2) +
1117                         alignTo(Member.MemberName.size(), 2);
1118    }
1119
1120    // AIX member table size.
1121    uint64_t MemberTableSize = 20 + // Number of members field
1122                               20 * MemberOffsets.size() +
1123                               MemberTableNameStrTblSize;
1124
1125    SmallString<0> SymNamesBuf32;
1126    SmallString<0> SymNamesBuf64;
1127    raw_svector_ostream SymNames32(SymNamesBuf32);
1128    raw_svector_ostream SymNames64(SymNamesBuf64);
1129
1130    if (ShouldWriteSymtab && NumSyms)
1131      // Generate the symbol names for the members.
1132      for (const auto &M : Data) {
1133        Expected<std::vector<unsigned>> SymbolsOrErr = getSymbols(
1134            M.SymFile.get(), 0,
1135            is64BitSymbolicFile(M.SymFile.get()) ? SymNames64 : SymNames32,
1136            nullptr);
1137        if (!SymbolsOrErr)
1138          return SymbolsOrErr.takeError();
1139      }
1140
1141    uint64_t MemberTableEndOffset =
1142        LastMemberEndOffset +
1143        alignTo(sizeof(object::BigArMemHdrType) + MemberTableSize, 2);
1144
1145    // In AIX OS, The 'GlobSymOffset' field in the fixed-length header contains
1146    // the offset to the 32-bit global symbol table, and the 'GlobSym64Offset'
1147    // contains the offset to the 64-bit global symbol table.
1148    uint64_t GlobalSymbolOffset =
1149        (ShouldWriteSymtab &&
1150         (WriteSymtab != SymtabWritingMode::BigArchive64) && NumSyms32 > 0)
1151            ? MemberTableEndOffset
1152            : 0;
1153
1154    uint64_t GlobalSymbolOffset64 = 0;
1155    uint64_t NumSyms64 = NumSyms - NumSyms32;
1156    if (ShouldWriteSymtab && (WriteSymtab != SymtabWritingMode::BigArchive32) &&
1157        NumSyms64 > 0) {
1158      if (GlobalSymbolOffset == 0)
1159        GlobalSymbolOffset64 = MemberTableEndOffset;
1160      else
1161        // If there is a global symbol table for 32-bit members,
1162        // the 64-bit global symbol table is after the 32-bit one.
1163        GlobalSymbolOffset64 =
1164            GlobalSymbolOffset + sizeof(object::BigArMemHdrType) +
1165            (NumSyms32 + 1) * 8 + alignTo(SymNamesBuf32.size(), 2);
1166    }
1167
1168    // Fixed Sized Header.
1169    printWithSpacePadding(Out, NewMembers.size() ? LastMemberEndOffset : 0,
1170                          20); // Offset to member table
1171    // If there are no file members in the archive, there will be no global
1172    // symbol table.
1173    printWithSpacePadding(Out, GlobalSymbolOffset, 20);
1174    printWithSpacePadding(Out, GlobalSymbolOffset64, 20);
1175    printWithSpacePadding(Out,
1176                          NewMembers.size()
1177                              ? sizeof(object::BigArchive::FixLenHdr) +
1178                                    Data[0].PreHeadPadSize
1179                              : 0,
1180                          20); // Offset to first archive member
1181    printWithSpacePadding(Out, NewMembers.size() ? LastMemberHeaderOffset : 0,
1182                          20); // Offset to last archive member
1183    printWithSpacePadding(
1184        Out, 0,
1185        20); // Offset to first member of free list - Not supported yet
1186
1187    for (const MemberData &M : Data) {
1188      Out << std::string(M.PreHeadPadSize, '\0');
1189      Out << M.Header << M.Data;
1190      if (M.Data.size() % 2)
1191        Out << '\0';
1192    }
1193
1194    if (NewMembers.size()) {
1195      // Member table.
1196      printBigArchiveMemberHeader(Out, "", sys::toTimePoint(0), 0, 0, 0,
1197                                  MemberTableSize, LastMemberHeaderOffset,
1198                                  GlobalSymbolOffset ? GlobalSymbolOffset
1199                                                     : GlobalSymbolOffset64);
1200      printWithSpacePadding(Out, MemberOffsets.size(), 20); // Number of members
1201      for (uint64_t MemberOffset : MemberOffsets)
1202        printWithSpacePadding(Out, MemberOffset,
1203                              20); // Offset to member file header.
1204      for (StringRef MemberName : MemberNames)
1205        Out << MemberName << '\0'; // Member file name, null byte padding.
1206
1207      if (MemberTableNameStrTblSize % 2)
1208        Out << '\0'; // Name table must be tail padded to an even number of
1209                     // bytes.
1210
1211      if (ShouldWriteSymtab) {
1212        // Write global symbol table for 32-bit file members.
1213        if (GlobalSymbolOffset) {
1214          writeSymbolTable(Out, Kind, Deterministic, Data, SymNamesBuf32,
1215                           *HeadersSize, NumSyms32, LastMemberEndOffset,
1216                           GlobalSymbolOffset64);
1217          // Add padding between the symbol tables, if needed.
1218          if (GlobalSymbolOffset64 && (SymNamesBuf32.size() % 2))
1219            Out << '\0';
1220        }
1221
1222        // Write global symbol table for 64-bit file members.
1223        if (GlobalSymbolOffset64)
1224          writeSymbolTable(Out, Kind, Deterministic, Data, SymNamesBuf64,
1225                           *HeadersSize, NumSyms64,
1226                           GlobalSymbolOffset ? GlobalSymbolOffset
1227                                              : LastMemberEndOffset,
1228                           0, true);
1229      }
1230    }
1231  }
1232  Out.flush();
1233  return Error::success();
1234}
1235
1236Error writeArchive(StringRef ArcName, ArrayRef<NewArchiveMember> NewMembers,
1237                   SymtabWritingMode WriteSymtab, object::Archive::Kind Kind,
1238                   bool Deterministic, bool Thin,
1239                   std::unique_ptr<MemoryBuffer> OldArchiveBuf, bool IsEC) {
1240  Expected<sys::fs::TempFile> Temp =
1241      sys::fs::TempFile::create(ArcName + ".temp-archive-%%%%%%%.a");
1242  if (!Temp)
1243    return Temp.takeError();
1244  raw_fd_ostream Out(Temp->FD, false);
1245
1246  if (Error E = writeArchiveToStream(Out, NewMembers, WriteSymtab, Kind,
1247                                     Deterministic, Thin, IsEC)) {
1248    if (Error DiscardError = Temp->discard())
1249      return joinErrors(std::move(E), std::move(DiscardError));
1250    return E;
1251  }
1252
1253  // At this point, we no longer need whatever backing memory
1254  // was used to generate the NewMembers. On Windows, this buffer
1255  // could be a mapped view of the file we want to replace (if
1256  // we're updating an existing archive, say). In that case, the
1257  // rename would still succeed, but it would leave behind a
1258  // temporary file (actually the original file renamed) because
1259  // a file cannot be deleted while there's a handle open on it,
1260  // only renamed. So by freeing this buffer, this ensures that
1261  // the last open handle on the destination file, if any, is
1262  // closed before we attempt to rename.
1263  OldArchiveBuf.reset();
1264
1265  return Temp->keep(ArcName);
1266}
1267
1268Expected<std::unique_ptr<MemoryBuffer>>
1269writeArchiveToBuffer(ArrayRef<NewArchiveMember> NewMembers,
1270                     SymtabWritingMode WriteSymtab, object::Archive::Kind Kind,
1271                     bool Deterministic, bool Thin) {
1272  SmallVector<char, 0> ArchiveBufferVector;
1273  raw_svector_ostream ArchiveStream(ArchiveBufferVector);
1274
1275  if (Error E = writeArchiveToStream(ArchiveStream, NewMembers, WriteSymtab,
1276                                     Kind, Deterministic, Thin, false))
1277    return std::move(E);
1278
1279  return std::make_unique<SmallVectorMemoryBuffer>(
1280      std::move(ArchiveBufferVector), /*RequiresNullTerminator=*/false);
1281}
1282
1283} // namespace llvm
1284