llvm-ar.cpp

//===-- llvm-ar.cpp - LLVM archive librarian utility ----------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Builds up (relatively) standard unix archive files (.a) containing LLVM
// bitcode or other files.
//
//===----------------------------------------------------------------------===//

#include"llvm/ADT/StringExtras.h"
#include"llvm/ADT/StringSwitch.h"
#include"llvm/ADT/Triple.h"
#include"llvm/IR/LLVMContext.h"
#include"llvm/Object/Archive.h"
#include"llvm/Object/ArchiveWriter.h"
#include"llvm/Object/MachO.h"
#include"llvm/Object/ObjectFile.h"
#include"llvm/Support/Chrono.h"
#include"llvm/Support/CommandLine.h"
#include"llvm/Support/Errc.h"
#include"llvm/Support/FileSystem.h"
#include"llvm/Support/Format.h"
#include"llvm/Support/FormatVariadic.h"
#include"llvm/Support/InitLLVM.h"
#include"llvm/Support/LineIterator.h"
#include"llvm/Support/MemoryBuffer.h"
#include"llvm/Support/Path.h"
#include"llvm/Support/Process.h"
#include"llvm/Support/StringSaver.h"
#include"llvm/Support/TargetSelect.h"
#include"llvm/Support/ToolOutputFile.h"
#include"llvm/Support/WithColor.h"
#include"llvm/Support/raw_ostream.h"
#include"llvm/ToolDrivers/llvm-dlltool/DlltoolDriver.h"
#include"llvm/ToolDrivers/llvm-lib/LibDriver.h"

#if !defined(_MSC_VER) && !defined(__MINGW32__)
#include<unistd.h>
#else
#include<io.h>
#endif

#ifdef _WIN32
#defineWIN32_LEAN_AND_MEAN
#include<windows.h>
#endif

usingnamespacellvm;

// The name this program was invoked as.
static StringRef ToolName;

// The basename of this program.
static StringRef Stem;

constchar RanlibHelp[] = R"(OVERVIEW: LLVM Ranlib (llvm-ranlib)

 This program generates an index to speed access to archives

USAGE: llvm-ranlib <archive-file>

OPTIONS:
 -h --help - Display available options
 -v --version - Display the version of this program
 -D - Use zero for timestamps and uids/gids (default)
 -U - Use actual timestamps and uids/gids
)";

constchar ArHelp[] = R"(OVERVIEW: LLVM Archiver

USAGE: llvm-ar [options] [-]<operation>[modifiers] [relpos] [count] <archive> [files]
 llvm-ar -M [<mri-script]

OPTIONS:
 --format - archive format to create
 =default - default
 =gnu - gnu
 =darwin - darwin
 =bsd - bsd
 --plugin=<string> - ignored for compatibility
 -h --help - display this help and exit
 --version - print the version and exit
 @<file> - read options from <file>

OPERATIONS:
 d - delete [files] from the archive
 m - move [files] in the archive
 p - print [files] found in the archive
 q - quick append [files] to the archive
 r - replace or insert [files] into the archive
 s - act as ranlib
 t - display contents of archive
 x - extract [files] from the archive

MODIFIERS:
 [a] - put [files] after [relpos]
 [b] - put [files] before [relpos] (same as [i])
 [c] - do not warn if archive had to be created
 [D] - use zero for timestamps and uids/gids (default)
 [h] - display this help and exit
 [i] - put [files] before [relpos] (same as [b])
 [l] - ignored for compatibility
 [L] - add archive's contents
 [N] - use instance [count] of name
 [o] - preserve original dates
 [O] - display member offsets
 [P] - use full names when matching (implied for thin archives)
 [s] - create an archive index (cf. ranlib)
 [S] - do not build a symbol table
 [T] - create a thin archive
 [u] - update only [files] newer than archive contents
 [U] - use actual timestamps and uids/gids
 [v] - be verbose about actions taken
 [V] - display the version and exit
)";

voidprintHelpMessage() {
if (Stem.contains_lower("ranlib"))
outs() << RanlibHelp;
elseif (Stem.contains_lower("ar"))
outs() << ArHelp;
}

staticunsigned MRILineNumber;
staticbool ParsingMRIScript;

// Show the error plus the usage message, and exit.
LLVM_ATTRIBUTE_NORETURN staticvoidbadUsage(Twine Error) {
WithColor::error(errs(), ToolName) << Error << "\n";
printHelpMessage();
exit(1);
}

// Show the error message and exit.
LLVM_ATTRIBUTE_NORETURN staticvoidfail(Twine Error) {
if (ParsingMRIScript) {
WithColor::error(errs(), ToolName)
 << "script line " << MRILineNumber << ": " << Error << "\n";
 } else {
WithColor::error(errs(), ToolName) << Error << "\n";
 }
exit(1);
}

staticvoidfailIfError(std::error_code EC, Twine Context = "") {
if (!EC)
return;

 std::string ContextStr = Context.str();
if (ContextStr.empty())
fail(EC.message());
fail(Context + ": " + EC.message());
}

staticvoidfailIfError(Error E, Twine Context = "") {
if (!E)
return;

handleAllErrors(std::move(E), [&](const llvm::ErrorInfoBase &EIB) {
 std::string ContextStr = Context.str();
if (ContextStr.empty())
fail(EIB.message());
fail(Context + ": " + EIB.message());
 });
}

static SmallVector<constchar *, 256> PositionalArgs;

staticbool MRI;

namespace {
enum Format { Default, GNU, BSD, DARWIN, Unknown };
}

static Format FormatType = Default;

static std::string Options;

// This enumeration delineates the kinds of operations on an archive
// that are permitted.
enum ArchiveOperation {
 Print, ///< Print the contents of the archive
 Delete, ///< Delete the specified members
 Move, ///< Move members to end or as given by {a,b,i} modifiers
 QuickAppend, ///< Quickly append to end of archive
 ReplaceOrInsert, ///< Replace or Insert members
 DisplayTable, ///< Display the table of contents
 Extract, ///< Extract files back to file system
 CreateSymTab ///< Create a symbol table in an existing archive
};

// Modifiers to follow operation to vary behavior
staticbool AddAfter = false; ///< 'a' modifier
staticbool AddBefore = false; ///< 'b' modifier
staticbool Create = false; ///< 'c' modifier
staticbool OriginalDates = false; ///< 'o' modifier
staticbool DisplayMemberOffsets = false; ///< 'O' modifier
staticbool CompareFullPath = false; ///< 'P' modifier
staticbool OnlyUpdate = false; ///< 'u' modifier
staticbool Verbose = false; ///< 'v' modifier
staticbool Symtab = true; ///< 's' modifier
staticbool Deterministic = true; ///< 'D' and 'U' modifiers
staticbool Thin = false; ///< 'T' modifier
staticbool AddLibrary = false; ///< 'L' modifier

// Relative Positional Argument (for insert/move). This variable holds
// the name of the archive member to which the 'a', 'b' or 'i' modifier
// refers. Only one of 'a', 'b' or 'i' can be specified so we only need
// one variable.
static std::string RelPos;

// Count parameter for 'N' modifier. This variable specifies which file should
// match for extract/delete operations when there are multiple matches. This is
// 1-indexed. A value of 0 is invalid, and implies 'N' is not used.
staticint CountParam = 0;

// This variable holds the name of the archive file as given on the
// command line.
static std::string ArchiveName;

static std::vector<std::unique_ptr<MemoryBuffer>> ArchiveBuffers;
static std::vector<std::unique_ptr<object::Archive>> Archives;

// This variable holds the list of member files to proecess, as given
// on the command line.
static std::vector<StringRef> Members;

// Static buffer to hold StringRefs.
static BumpPtrAllocator Alloc;

// Extract the member filename from the command line for the [relpos] argument
// associated with a, b, and i modifiers
staticvoidgetRelPos() {
if (PositionalArgs.empty())
fail("expected [relpos] for 'a', 'b', or 'i' modifier");
 RelPos = PositionalArgs[0];
 PositionalArgs.erase(PositionalArgs.begin());
}

// Extract the parameter from the command line for the [count] argument
// associated with the N modifier
staticvoidgetCountParam() {
if (PositionalArgs.empty())
badUsage("expected [count] for 'N' modifier");
auto CountParamArg = StringRef(PositionalArgs[0]);
if (CountParamArg.getAsInteger(10, CountParam))
badUsage("value for [count] must be numeric, got: " + CountParamArg);
if (CountParam < 1)
badUsage("value for [count] must be positive, got: " + CountParamArg);
 PositionalArgs.erase(PositionalArgs.begin());
}

// Get the archive file name from the command line
staticvoidgetArchive() {
if (PositionalArgs.empty())
badUsage("an archive name must be specified");
 ArchiveName = PositionalArgs[0];
 PositionalArgs.erase(PositionalArgs.begin());
}

static object::Archive &readLibrary(const Twine &Library) {
auto BufOrErr = MemoryBuffer::getFile(Library, -1, false);
failIfError(BufOrErr.getError(), "could not open library " + Library);
 ArchiveBuffers.push_back(std::move(*BufOrErr));
auto LibOrErr =
object::Archive::create(ArchiveBuffers.back()->getMemBufferRef());
failIfError(errorToErrorCode(LibOrErr.takeError()),
"could not parse library");
 Archives.push_back(std::move(*LibOrErr));
return *Archives.back();
}

staticvoidrunMRIScript();

// Parse the command line options as presented and return the operation
// specified. Process all modifiers and check to make sure that constraints on
// modifier/operation pairs have not been violated.
static ArchiveOperation parseCommandLine() {
if (MRI) {
if (!PositionalArgs.empty() || !Options.empty())
badUsage("cannot mix -M and other options");
runMRIScript();
 }

// Keep track of number of operations. We can only specify one
// per execution.
unsigned NumOperations = 0;

// Keep track of the number of positional modifiers (a,b,i). Only
// one can be specified.
unsigned NumPositional = 0;

// Keep track of which operation was requested
 ArchiveOperation Operation;

bool MaybeJustCreateSymTab = false;

for (unsigned i = 0; i < Options.size(); ++i) {
switch (Options[i]) {
case'd':
 ++NumOperations;
 Operation = Delete;
break;
case'm':
 ++NumOperations;
 Operation = Move;
break;
case'p':
 ++NumOperations;
 Operation = Print;
break;
case'q':
 ++NumOperations;
 Operation = QuickAppend;
break;
case'r':
 ++NumOperations;
 Operation = ReplaceOrInsert;
break;
case't':
 ++NumOperations;
 Operation = DisplayTable;
break;
case'x':
 ++NumOperations;
 Operation = Extract;
break;
case'c':
 Create = true;
break;
case'l': /* accepted but unused */
break;
case'o':
 OriginalDates = true;
break;
case'O':
 DisplayMemberOffsets = true;
break;
case'P':
 CompareFullPath = true;
break;
case's':
 Symtab = true;
 MaybeJustCreateSymTab = true;
break;
case'S':
 Symtab = false;
break;
case'u':
 OnlyUpdate = true;
break;
case'v':
 Verbose = true;
break;
case'a':
getRelPos();
 AddAfter = true;
 NumPositional++;
break;
case'b':
getRelPos();
 AddBefore = true;
 NumPositional++;
break;
case'i':
getRelPos();
 AddBefore = true;
 NumPositional++;
break;
case'D':
 Deterministic = true;
break;
case'U':
 Deterministic = false;
break;
case'N':
getCountParam();
break;
case'T':
 Thin = true;
// Thin archives store path names, so P should be forced.
 CompareFullPath = true;
break;
case'L':
 AddLibrary = true;
break;
case'V':
cl::PrintVersionMessage();
exit(0);
case'h':
printHelpMessage();
exit(0);
default:
badUsage(std::string("unknown option ") + Options[i]);
 }
 }

// At this point, the next thing on the command line must be
// the archive name.
getArchive();

// Everything on the command line at this point is a member.
 Members.assign(PositionalArgs.begin(), PositionalArgs.end());

if (NumOperations == 0 && MaybeJustCreateSymTab) {
 NumOperations = 1;
 Operation = CreateSymTab;
if (!Members.empty())
badUsage("the 's' operation takes only an archive as argument");
 }

// Perform various checks on the operation/modifier specification
// to make sure we are dealing with a legal request.
if (NumOperations == 0)
badUsage("you must specify at least one of the operations");
if (NumOperations > 1)
badUsage("only one operation may be specified");
if (NumPositional > 1)
badUsage("you may only specify one of 'a', 'b', and 'i' modifiers");
if (AddAfter || AddBefore)
if (Operation != Move && Operation != ReplaceOrInsert)
badUsage("the 'a', 'b' and 'i' modifiers can only be specified with "
"the 'm' or 'r' operations");
if (CountParam)
if (Operation != Extract && Operation != Delete)
badUsage("the 'N' modifier can only be specified with the 'x' or 'd' "
"operations");
if (OriginalDates && Operation != Extract)
badUsage("the 'o' modifier is only applicable to the 'x' operation");
if (OnlyUpdate && Operation != ReplaceOrInsert)
badUsage("the 'u' modifier is only applicable to the 'r' operation");
if (AddLibrary && Operation != QuickAppend)
badUsage("the 'L' modifier is only applicable to the 'q' operation");

// Return the parsed operation to the caller
return Operation;
}

// Implements the 'p' operation. This function traverses the archive
// looking for members that match the path list.
staticvoiddoPrint(StringRef Name, const object::Archive::Child &C) {
if (Verbose)
outs() << "Printing " << Name << "\n";

 Expected<StringRef> DataOrErr = C.getBuffer();
failIfError(DataOrErr.takeError());
 StringRef Data = *DataOrErr;
outs().write(Data.data(), Data.size());
}

// Utility function for printing out the file mode when the 't' operation is in
// verbose mode.
staticvoidprintMode(unsigned mode) {
outs() << ((mode & 004) ? "r" : "-");
outs() << ((mode & 002) ? "w" : "-");
outs() << ((mode & 001) ? "x" : "-");
}

// Implement the 't' operation. This function prints out just
// the file names of each of the members. However, if verbose mode is requested
// ('v' modifier) then the file type, permission mode, user, group, size, and
// modification time are also printed.
staticvoiddoDisplayTable(StringRef Name, const object::Archive::Child &C) {
if (Verbose) {
 Expected<sys::fs::perms> ModeOrErr = C.getAccessMode();
failIfError(ModeOrErr.takeError());
 sys::fs::perms Mode = ModeOrErr.get();
printMode((Mode >> 6) & 007);
printMode((Mode >> 3) & 007);
printMode(Mode & 007);
 Expected<unsigned> UIDOrErr = C.getUID();
failIfError(UIDOrErr.takeError());
outs() << '' << UIDOrErr.get();
 Expected<unsigned> GIDOrErr = C.getGID();
failIfError(GIDOrErr.takeError());
outs() << '/' << GIDOrErr.get();
 Expected<uint64_t> Size = C.getSize();
failIfError(Size.takeError());
outs() << '' << format("%6llu", Size.get());
auto ModTimeOrErr = C.getLastModified();
failIfError(ModTimeOrErr.takeError());
// Note: formatv() only handles the default TimePoint<>, which is in
// nanoseconds.
// TODO: fix format_provider<TimePoint<>> to allow other units.
 sys::TimePoint<> ModTimeInNs = ModTimeOrErr.get();
outs() << '' << formatv("{0:%b %e %H:%M %Y}", ModTimeInNs);
outs() << '';
 }

if (C.getParent()->isThin()) {
if (!sys::path::is_absolute(Name)) {
 StringRef ParentDir = sys::path::parent_path(ArchiveName);
if (!ParentDir.empty())
outs() << sys::path::convert_to_slash(ParentDir) << '/';
 }
outs() << Name;
 } else {
outs() << Name;
if (DisplayMemberOffsets)
outs() << " 0x" << utohexstr(C.getDataOffset(), true);
 }
outs() << '\n';
}

static std::string normalizePath(StringRef Path) {
return CompareFullPath ? sys::path::convert_to_slash(Path)
 : std::string(sys::path::filename(Path));
}

staticboolcomparePaths(StringRef Path1, StringRef Path2) {
// When on Windows this function calls CompareStringOrdinal
// as Windows file paths are case-insensitive. 
// CompareStringOrdinal compares two Unicode strings for
// binary equivalence and allows for case insensitivity.
#ifdef _WIN32
 SmallVector<wchar_t, 128> WPath1, WPath2;
failIfError(sys::path::widenPath(normalizePath(Path1), WPath1));
failIfError(sys::path::widenPath(normalizePath(Path2), WPath2));

returnCompareStringOrdinal(WPath1.data(), WPath1.size(), WPath2.data(),
 WPath2.size(), true) == CSTR_EQUAL;
#else
returnnormalizePath(Path1) == normalizePath(Path2);
#endif
}

// Implement the 'x' operation. This function extracts files back to the file
// system.
staticvoiddoExtract(StringRef Name, const object::Archive::Child &C) {
// Retain the original mode.
 Expected<sys::fs::perms> ModeOrErr = C.getAccessMode();
failIfError(ModeOrErr.takeError());
 sys::fs::perms Mode = ModeOrErr.get();

 llvm::StringRef outputFilePath = sys::path::filename(Name);
if (Verbose)
outs() << "x - " << outputFilePath << '\n';

int FD;
failIfError(sys::fs::openFileForWrite(outputFilePath, FD,
 sys::fs::CD_CreateAlways,
 sys::fs::OF_None, Mode),
 Name);

 {
 raw_fd_ostream file(FD, false);

// Get the data and its length
 Expected<StringRef> BufOrErr = C.getBuffer();
failIfError(BufOrErr.takeError());
 StringRef Data = BufOrErr.get();

// Write the data.
 file.write(Data.data(), Data.size());
 }

// If we're supposed to retain the original modification times, etc. do so
// now.
if (OriginalDates) {
auto ModTimeOrErr = C.getLastModified();
failIfError(ModTimeOrErr.takeError());
failIfError(
sys::fs::setLastAccessAndModificationTime(FD, ModTimeOrErr.get()));
 }

if (close(FD))
fail("Could not close the file");
}

staticboolshouldCreateArchive(ArchiveOperation Op) {
switch (Op) {
case Print:
case Delete:
case Move:
case DisplayTable:
case Extract:
case CreateSymTab:
returnfalse;

case QuickAppend:
case ReplaceOrInsert:
returntrue;
 }

llvm_unreachable("Missing entry in covered switch.");
}

staticvoidperformReadOperation(ArchiveOperation Operation,
 object::Archive *OldArchive) {
if (Operation == Extract && OldArchive->isThin())
fail("extracting from a thin archive is not supported");

bool Filter = !Members.empty();
 StringMap<int> MemberCount;
 {
 Error Err = Error::success();
for (auto &C : OldArchive->children(Err)) {
 Expected<StringRef> NameOrErr = C.getName();
failIfError(NameOrErr.takeError());
 StringRef Name = NameOrErr.get();

if (Filter) {
auto I = find_if(Members, [Name](StringRef Path) {
returncomparePaths(Name, Path);
 });
if (I == Members.end())
continue;
if (CountParam && ++MemberCount[Name] != CountParam)
continue;
 Members.erase(I);
 }

switch (Operation) {
default:
llvm_unreachable("Not a read operation");
case Print:
doPrint(Name, C);
break;
case DisplayTable:
doDisplayTable(Name, C);
break;
case Extract:
doExtract(Name, C);
break;
 }
 }
failIfError(std::move(Err));
 }

if (Members.empty())
return;
for (StringRef Name : Members)
WithColor::error(errs(), ToolName) << "'" << Name << "' was not found\n";
exit(1);
}

staticvoidaddChildMember(std::vector<NewArchiveMember> &Members,
const object::Archive::Child &M,
bool FlattenArchive = false) {
if (Thin && !M.getParent()->isThin())
fail("cannot convert a regular archive to a thin one");
 Expected<NewArchiveMember> NMOrErr =
NewArchiveMember::getOldMember(M, Deterministic);
failIfError(NMOrErr.takeError());
// If the child member we're trying to add is thin, use the path relative to
// the archive it's in, so the file resolves correctly.
if (Thin && FlattenArchive) {
 StringSaver Saver(Alloc);
 Expected<std::string> FileNameOrErr = M.getName();
failIfError(FileNameOrErr.takeError());
if (sys::path::is_absolute(*FileNameOrErr)) {
 NMOrErr->MemberName = Saver.save(sys::path::convert_to_slash(*FileNameOrErr));
 } else {
 FileNameOrErr = M.getFullName();
failIfError(FileNameOrErr.takeError());
 Expected<std::string> PathOrErr =
computeArchiveRelativePath(ArchiveName, *FileNameOrErr);
 NMOrErr->MemberName = Saver.save(
 PathOrErr ? *PathOrErr : sys::path::convert_to_slash(*FileNameOrErr));
 }
 }
if (FlattenArchive &&
identify_magic(NMOrErr->Buf->getBuffer()) == file_magic::archive) {
 Expected<std::string> FileNameOrErr = M.getFullName();
failIfError(FileNameOrErr.takeError());
 object::Archive &Lib = readLibrary(*FileNameOrErr);
// When creating thin archives, only flatten if the member is also thin.
if (!Thin || Lib.isThin()) {
 Error Err = Error::success();
// Only Thin archives are recursively flattened.
for (auto &Child : Lib.children(Err))
addChildMember(Members, Child, /*FlattenArchive=*/Thin);
failIfError(std::move(Err));
return;
 }
 }
 Members.push_back(std::move(*NMOrErr));
}

staticvoidaddMember(std::vector<NewArchiveMember> &Members,
 StringRef FileName, bool FlattenArchive = false) {
 Expected<NewArchiveMember> NMOrErr =
NewArchiveMember::getFile(FileName, Deterministic);
failIfError(NMOrErr.takeError(), FileName);
 StringSaver Saver(Alloc);
// For regular archives, use the basename of the object path for the member
// name. For thin archives, use the full relative paths so the file resolves
// correctly.
if (!Thin) {
 NMOrErr->MemberName = sys::path::filename(NMOrErr->MemberName);
 } else {
if (sys::path::is_absolute(FileName))
 NMOrErr->MemberName = Saver.save(sys::path::convert_to_slash(FileName));
else {
 Expected<std::string> PathOrErr =
computeArchiveRelativePath(ArchiveName, FileName);
 NMOrErr->MemberName = Saver.save(
 PathOrErr ? *PathOrErr : sys::path::convert_to_slash(FileName));
 }
 }

if (FlattenArchive &&
identify_magic(NMOrErr->Buf->getBuffer()) == file_magic::archive) {
 object::Archive &Lib = readLibrary(FileName);
// When creating thin archives, only flatten if the member is also thin.
if (!Thin || Lib.isThin()) {
 Error Err = Error::success();
// Only Thin archives are recursively flattened.
for (auto &Child : Lib.children(Err))
addChildMember(Members, Child, /*FlattenArchive=*/Thin);
failIfError(std::move(Err));
return;
 }
 }
 Members.push_back(std::move(*NMOrErr));
}

enum InsertAction {
 IA_AddOldMember,
 IA_AddNewMember,
 IA_Delete,
 IA_MoveOldMember,
 IA_MoveNewMember
};

static InsertAction computeInsertAction(ArchiveOperation Operation,
const object::Archive::Child &Member,
 StringRef Name,
 std::vector<StringRef>::iterator &Pos,
 StringMap<int> &MemberCount) {
if (Operation == QuickAppend || Members.empty())
return IA_AddOldMember;
auto MI = find_if(
 Members, [Name](StringRef Path) { returncomparePaths(Name, Path); });

if (MI == Members.end())
return IA_AddOldMember;

 Pos = MI;

if (Operation == Delete) {
if (CountParam && ++MemberCount[Name] != CountParam)
return IA_AddOldMember;
return IA_Delete;
 }

if (Operation == Move)
return IA_MoveOldMember;

if (Operation == ReplaceOrInsert) {
if (!OnlyUpdate) {
if (RelPos.empty())
return IA_AddNewMember;
return IA_MoveNewMember;
 }

// We could try to optimize this to a fstat, but it is not a common
// operation.
 sys::fs::file_status Status;
failIfError(sys::fs::status(*MI, Status), *MI);
auto ModTimeOrErr = Member.getLastModified();
failIfError(ModTimeOrErr.takeError());
if (Status.getLastModificationTime() < ModTimeOrErr.get()) {
if (RelPos.empty())
return IA_AddOldMember;
return IA_MoveOldMember;
 }

if (RelPos.empty())
return IA_AddNewMember;
return IA_MoveNewMember;
 }
llvm_unreachable("No such operation");
}

// We have to walk this twice and computing it is not trivial, so creating an
// explicit std::vector is actually fairly efficient.
static std::vector<NewArchiveMember>
computeNewArchiveMembers(ArchiveOperation Operation,
 object::Archive *OldArchive) {
 std::vector<NewArchiveMember> Ret;
 std::vector<NewArchiveMember> Moved;
int InsertPos = -1;
if (OldArchive) {
 Error Err = Error::success();
 StringMap<int> MemberCount;
for (auto &Child : OldArchive->children(Err)) {
int Pos = Ret.size();
 Expected<StringRef> NameOrErr = Child.getName();
failIfError(NameOrErr.takeError());
 std::string Name = NameOrErr.get();
if (comparePaths(Name, RelPos)) {
assert(AddAfter || AddBefore);
if (AddBefore)
 InsertPos = Pos;
else
 InsertPos = Pos + 1;
 }

 std::vector<StringRef>::iterator MemberI = Members.end();
 InsertAction Action =
computeInsertAction(Operation, Child, Name, MemberI, MemberCount);
switch (Action) {
case IA_AddOldMember:
addChildMember(Ret, Child, /*FlattenArchive=*/Thin);
break;
case IA_AddNewMember:
addMember(Ret, *MemberI);
break;
case IA_Delete:
break;
case IA_MoveOldMember:
addChildMember(Moved, Child, /*FlattenArchive=*/Thin);
break;
case IA_MoveNewMember:
addMember(Moved, *MemberI);
break;
 }
// When processing elements with the count param, we need to preserve the
// full members list when iterating over all archive members. For
// instance, "llvm-ar dN 2 archive.a member.o" should delete the second
// file named member.o it sees; we are not done with member.o the first
// time we see it in the archive.
if (MemberI != Members.end() && !CountParam)
 Members.erase(MemberI);
 }
failIfError(std::move(Err));
 }

if (Operation == Delete)
return Ret;

if (!RelPos.empty() && InsertPos == -1)
fail("insertion point not found");

if (RelPos.empty())
 InsertPos = Ret.size();

assert(unsigned(InsertPos) <= Ret.size());
int Pos = InsertPos;
for (auto &M : Moved) {
 Ret.insert(Ret.begin() + Pos, std::move(M));
 ++Pos;
 }

if (AddLibrary) {
assert(Operation == QuickAppend);
for (auto &Member : Members)
addMember(Ret, Member, /*FlattenArchive=*/true);
return Ret;
 }

 std::vector<NewArchiveMember> NewMembers;
for (auto &Member : Members)
addMember(NewMembers, Member, /*FlattenArchive=*/Thin);
 Ret.reserve(Ret.size() + NewMembers.size());
std::move(NewMembers.begin(), NewMembers.end(),
std::inserter(Ret, std::next(Ret.begin(), InsertPos)));

return Ret;
}

static object::Archive::Kind getDefaultForHost() {
returnTriple(sys::getProcessTriple()).isOSDarwin()
 ? object::Archive::K_DARWIN
 : object::Archive::K_GNU;
}

static object::Archive::Kind getKindFromMember(const NewArchiveMember &Member) {
 Expected<std::unique_ptr<object::ObjectFile>> OptionalObject =
object::ObjectFile::createObjectFile(Member.Buf->getMemBufferRef());

if (OptionalObject)
return isa<object::MachOObjectFile>(**OptionalObject)
 ? object::Archive::K_DARWIN
 : object::Archive::K_GNU;

// squelch the error in case we had a non-object file
consumeError(OptionalObject.takeError());
returngetDefaultForHost();
}

staticvoidperformWriteOperation(ArchiveOperation Operation,
 object::Archive *OldArchive,
 std::unique_ptr<MemoryBuffer> OldArchiveBuf,
 std::vector<NewArchiveMember> *NewMembersP) {
 std::vector<NewArchiveMember> NewMembers;
if (!NewMembersP)
 NewMembers = computeNewArchiveMembers(Operation, OldArchive);

 object::Archive::Kind Kind;
switch (FormatType) {
case Default:
if (Thin)
 Kind = object::Archive::K_GNU;
elseif (OldArchive)
 Kind = OldArchive->kind();
elseif (NewMembersP)
 Kind = !NewMembersP->empty() ? getKindFromMember(NewMembersP->front())
 : getDefaultForHost();
else
 Kind = !NewMembers.empty() ? getKindFromMember(NewMembers.front())
 : getDefaultForHost();
break;
case GNU:
 Kind = object::Archive::K_GNU;
break;
case BSD:
if (Thin)
fail("only the gnu format has a thin mode");
 Kind = object::Archive::K_BSD;
break;
case DARWIN:
if (Thin)
fail("only the gnu format has a thin mode");
 Kind = object::Archive::K_DARWIN;
break;
case Unknown:
llvm_unreachable("");
 }

 Error E =
writeArchive(ArchiveName, NewMembersP ? *NewMembersP : NewMembers, Symtab,
 Kind, Deterministic, Thin, std::move(OldArchiveBuf));
failIfError(std::move(E), ArchiveName);
}

staticvoidcreateSymbolTable(object::Archive *OldArchive) {
// When an archive is created or modified, if the s option is given, the
// resulting archive will have a current symbol table. If the S option
// is given, it will have no symbol table.
// In summary, we only need to update the symbol table if we have none.
// This is actually very common because of broken build systems that think
// they have to run ranlib.
if (OldArchive->hasSymbolTable())
return;

performWriteOperation(CreateSymTab, OldArchive, nullptr, nullptr);
}

staticvoidperformOperation(ArchiveOperation Operation,
 object::Archive *OldArchive,
 std::unique_ptr<MemoryBuffer> OldArchiveBuf,
 std::vector<NewArchiveMember> *NewMembers) {
switch (Operation) {
case Print:
case DisplayTable:
case Extract:
performReadOperation(Operation, OldArchive);
return;

case Delete:
case Move:
case QuickAppend:
case ReplaceOrInsert:
performWriteOperation(Operation, OldArchive, std::move(OldArchiveBuf),
 NewMembers);
return;
case CreateSymTab:
createSymbolTable(OldArchive);
return;
 }
llvm_unreachable("Unknown operation.");
}

staticintperformOperation(ArchiveOperation Operation,
 std::vector<NewArchiveMember> *NewMembers) {
// Create or open the archive object.
 ErrorOr<std::unique_ptr<MemoryBuffer>> Buf =
MemoryBuffer::getFile(ArchiveName, -1, false);
 std::error_code EC = Buf.getError();
if (EC && EC != errc::no_such_file_or_directory)
fail("error opening '" + ArchiveName + "': " + EC.message());

if (!EC) {
 Error Err = Error::success();
 object::Archive Archive(Buf.get()->getMemBufferRef(), Err);
failIfError(std::move(Err), "unable to load '" + ArchiveName + "'");
if (Archive.isThin())
 CompareFullPath = true;
performOperation(Operation, &Archive, std::move(Buf.get()), NewMembers);
return0;
 }

assert(EC == errc::no_such_file_or_directory);

if (!shouldCreateArchive(Operation)) {
failIfError(EC, Twine("error loading '") + ArchiveName + "'");
 } else {
if (!Create) {
// Produce a warning if we should and we're creating the archive
WithColor::warning(errs(), ToolName)
 << "creating " << ArchiveName << "\n";
 }
 }