llvm/lib/ObjCopy/Archive.cpp

   1 //===- Archive.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 #include "Archive.h"
  10 #include "llvm/ObjCopy/CommonConfig.h"
  11 #include "llvm/ObjCopy/MultiFormatConfig.h"
  12 #include "llvm/ObjCopy/ObjCopy.h"
  13 #include "llvm/Object/Error.h"
  14 #include "llvm/Support/FileOutputBuffer.h"
  15 #include "llvm/Support/SmallVectorMemoryBuffer.h"
  16
  17 namespace llvm {
  18 namespace objcopy {
  19
  20 using namespace llvm::object;
  21
  22 Expected<std::vector<NewArchiveMember>>
  23 createNewArchiveMembers(const MultiFormatConfig &Config, const Archive &Ar) {
  24   std::vector<NewArchiveMember> NewArchiveMembers;
  25   Error Err = Error::success();
  26   for (const Archive::Child &Child : Ar.children(Err)) {
  27     Expected<StringRef> ChildNameOrErr = Child.getName();
  28     if (!ChildNameOrErr)
  29       return createFileError(Ar.getFileName(), ChildNameOrErr.takeError());
  30
  31     Expected<std::unique_ptr<Binary>> ChildOrErr = Child.getAsBinary();
  32     if (!ChildOrErr)
  33       return createFileError(Ar.getFileName() + "(" + *ChildNameOrErr + ")",
  34                              ChildOrErr.takeError());
  35
  36     SmallVector<char, 0> Buffer;
  37     raw_svector_ostream MemStream(Buffer);
  38
  39     if (Error E = executeObjcopyOnBinary(Config, *ChildOrErr->get(), MemStream))
  40       return std::move(E);
  41
  42     Expected<NewArchiveMember> Member = NewArchiveMember::getOldMember(
  43         Child, Config.getCommonConfig().DeterministicArchives);
  44     if (!Member)
  45       return createFileError(Ar.getFileName(), Member.takeError());
  46
  47     Member->Buf = std::make_unique<SmallVectorMemoryBuffer>(
  48         std::move(Buffer), ChildNameOrErr.get());
  49     Member->MemberName = Member->Buf->getBufferIdentifier();
  50     NewArchiveMembers.push_back(std::move(*Member));
  51   }
  52   if (Err)
  53     return createFileError(Config.getCommonConfig().InputFilename,
  54                            std::move(Err));
  55   return std::move(NewArchiveMembers);
  56 }
  57
  58 // For regular archives this function simply calls llvm::writeArchive,
  59 // For thin archives it writes the archive file itself as well as its members.
  60 static Error deepWriteArchive(StringRef ArcName,
  61                               ArrayRef<NewArchiveMember> NewMembers,
  62                               SymtabWritingMode WriteSymtab,
  63                               object::Archive::Kind Kind, bool Deterministic,
  64                               bool Thin) {
  65   if (Kind == object::Archive::K_BSD && !NewMembers.empty() &&
  66       NewMembers.front().detectKindFromObject() == object::Archive::K_DARWIN)
  67     Kind = object::Archive::K_DARWIN;
  68
  69   if (Error E = writeArchive(ArcName, NewMembers, WriteSymtab, Kind,
  70                              Deterministic, Thin))
  71     return createFileError(ArcName, std::move(E));
  72
  73   if (!Thin)
  74     return Error::success();
  75
  76   for (const NewArchiveMember &Member : NewMembers) {
  77     // For regular files (as is the case for deepWriteArchive),
  78     // FileOutputBuffer::create will return OnDiskBuffer.
  79     // OnDiskBuffer uses a temporary file and then renames it. So in reality
  80     // there is no inefficiency / duplicated in-memory buffers in this case. For
  81     // now in-memory buffers can not be completely avoided since
  82     // NewArchiveMember still requires them even though writeArchive does not
  83     // write them on disk.
  84     Expected<std::unique_ptr<FileOutputBuffer>> FB =
  85         FileOutputBuffer::create(Member.MemberName, Member.Buf->getBufferSize(),
  86                                  FileOutputBuffer::F_executable);
  87     if (!FB)
  88       return FB.takeError();
  89     std::copy(Member.Buf->getBufferStart(), Member.Buf->getBufferEnd(),
  90               (*FB)->getBufferStart());
  91     if (Error E = (*FB)->commit())
  92       return E;
  93   }
  94   return Error::success();
  95 }
  96
  97 Error executeObjcopyOnArchive(const MultiFormatConfig &Config,
  98                               const object::Archive &Ar) {
  99   Expected<std::vector<NewArchiveMember>> NewArchiveMembersOrErr =
 100       createNewArchiveMembers(Config, Ar);
 101   if (!NewArchiveMembersOrErr)
 102     return NewArchiveMembersOrErr.takeError();
 103   const CommonConfig &CommonConfig = Config.getCommonConfig();
 104   return deepWriteArchive(CommonConfig.OutputFilename, *NewArchiveMembersOrErr,
 105                           Ar.hasSymbolTable() ? SymtabWritingMode::NormalSymtab
 106                                               : SymtabWritingMode::NoSymtab,
 107                           Ar.kind(), CommonConfig.DeterministicArchives,
 108                           Ar.isThin());
 109 }
 110
 111 } // end namespace objcopy
 112 } // end namespace llvm