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/Object/MachO.h"
15 #include "llvm/Support/FileOutputBuffer.h"
16 #include "llvm/Support/SmallVectorMemoryBuffer.h"
17 
18 namespace llvm {
19 namespace objcopy {
20 
21 using namespace llvm::object;
22 
23 Expected<std::vector<NewArchiveMember>>
24 createNewArchiveMembers(const MultiFormatConfig &Config, const Archive &Ar) {
25   std::vector<NewArchiveMember> NewArchiveMembers;
26   Error Err = Error::success();
27   for (const Archive::Child &Child : Ar.children(Err)) {
28     Expected<StringRef> ChildNameOrErr = Child.getName();
29     if (!ChildNameOrErr)
30       return createFileError(Ar.getFileName(), ChildNameOrErr.takeError());
31 
32     Expected<std::unique_ptr<Binary>> ChildOrErr = Child.getAsBinary();
33     if (!ChildOrErr)
34       return createFileError(Ar.getFileName() + "(" + *ChildNameOrErr + ")",
35                              ChildOrErr.takeError());
36 
37     SmallVector<char, 0> Buffer;
38     raw_svector_ostream MemStream(Buffer);
39 
40     if (Error E = executeObjcopyOnBinary(Config, *ChildOrErr->get(), MemStream))
41       return std::move(E);
42 
43     Expected<NewArchiveMember> Member = NewArchiveMember::getOldMember(
44         Child, Config.getCommonConfig().DeterministicArchives);
45     if (!Member)
46       return createFileError(Ar.getFileName(), Member.takeError());
47 
48     Member->Buf = std::make_unique<SmallVectorMemoryBuffer>(
49         std::move(Buffer), ChildNameOrErr.get());
50     Member->MemberName = Member->Buf->getBufferIdentifier();
51     NewArchiveMembers.push_back(std::move(*Member));
52   }
53   if (Err)
54     return createFileError(Config.getCommonConfig().InputFilename,
55                            std::move(Err));
56   return std::move(NewArchiveMembers);
57 }
58 
59 // For regular archives this function simply calls llvm::writeArchive,
60 // For thin archives it writes the archive file itself as well as its members.
61 static Error deepWriteArchive(StringRef ArcName,
62                               ArrayRef<NewArchiveMember> NewMembers,
63                               bool WriteSymtab, object::Archive::Kind Kind,
64                               bool Deterministic, 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(), Ar.kind(),
106                           CommonConfig.DeterministicArchives, Ar.isThin());
107 }
108 
109 } // end namespace objcopy
110 } // end namespace llvm
111