[llvm-objcopy] Add ability to copy MachO object files
This diff implements first bits for copying (without modification) MachO object files.
Test plan: make check-all
Differential revision: https://reviews.llvm.org/D54674
llvm-svn: 352944
diff --git a/llvm/tools/llvm-objcopy/MachO/MachOWriter.cpp b/llvm/tools/llvm-objcopy/MachO/MachOWriter.cpp
new file mode 100644
index 0000000..10dce52
--- /dev/null
+++ b/llvm/tools/llvm-objcopy/MachO/MachOWriter.cpp
@@ -0,0 +1,353 @@
+//===- MachOWriter.cpp ------------------------------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MachOWriter.h"
+#include "../llvm-objcopy.h"
+#include "Object.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/BinaryFormat/MachO.h"
+#include "llvm/Object/MachO.h"
+#include <memory>
+
+namespace llvm {
+namespace objcopy {
+namespace macho {
+
+size_t MachOWriter::headerSize() const {
+ return Is64Bit ? sizeof(MachO::mach_header_64) : sizeof(MachO::mach_header);
+}
+
+size_t MachOWriter::loadCommandsSize() const { return O.Header.SizeOfCmds; }
+
+size_t MachOWriter::symTableSize() const {
+ return O.SymTable.NameList.size() *
+ (Is64Bit ? sizeof(MachO::nlist_64) : sizeof(MachO::nlist));
+}
+
+size_t MachOWriter::strTableSize() const {
+ size_t S = 0;
+ for (const auto &Str : O.StrTable.Strings)
+ S += Str.size();
+ S += (O.StrTable.Strings.empty() ? 0 : O.StrTable.Strings.size() - 1);
+ return S;
+}
+
+size_t MachOWriter::totalSize() const {
+ // Going from tail to head and looking for an appropriate "anchor" to
+ // calculate the total size assuming that all the offsets are either valid
+ // ("true") or 0 (0 indicates that the corresponding part is missing).
+
+ SmallVector<size_t, 7> Ends;
+ if (O.SymTabCommandIndex) {
+ const MachO::symtab_command &SymTabCommand =
+ O.LoadCommands[*O.SymTabCommandIndex]
+ .MachOLoadCommand.symtab_command_data;
+ if (SymTabCommand.symoff) {
+ assert((SymTabCommand.nsyms == O.SymTable.NameList.size()) &&
+ "Incorrect number of symbols");
+ Ends.push_back(SymTabCommand.symoff + symTableSize());
+ }
+ if (SymTabCommand.stroff) {
+ assert((SymTabCommand.strsize == strTableSize()) &&
+ "Incorrect string table size");
+ Ends.push_back(SymTabCommand.stroff + SymTabCommand.strsize);
+ }
+ }
+ if (O.DyLdInfoCommandIndex) {
+ const MachO::dyld_info_command &DyLdInfoCommand =
+ O.LoadCommands[*O.DyLdInfoCommandIndex]
+ .MachOLoadCommand.dyld_info_command_data;
+ if (DyLdInfoCommand.rebase_off) {
+ assert((DyLdInfoCommand.rebase_size == O.Rebases.Opcodes.size()) &&
+ "Incorrect rebase opcodes size");
+ Ends.push_back(DyLdInfoCommand.rebase_off + DyLdInfoCommand.rebase_size);
+ }
+ if (DyLdInfoCommand.bind_off) {
+ assert((DyLdInfoCommand.bind_size == O.Binds.Opcodes.size()) &&
+ "Incorrect bind opcodes size");
+ Ends.push_back(DyLdInfoCommand.bind_off + DyLdInfoCommand.bind_size);
+ }
+ if (DyLdInfoCommand.weak_bind_off) {
+ assert((DyLdInfoCommand.weak_bind_size == O.WeakBinds.Opcodes.size()) &&
+ "Incorrect weak bind opcodes size");
+ Ends.push_back(DyLdInfoCommand.weak_bind_off +
+ DyLdInfoCommand.weak_bind_size);
+ }
+ if (DyLdInfoCommand.lazy_bind_off) {
+ assert((DyLdInfoCommand.lazy_bind_size == O.LazyBinds.Opcodes.size()) &&
+ "Incorrect lazy bind opcodes size");
+ Ends.push_back(DyLdInfoCommand.lazy_bind_off +
+ DyLdInfoCommand.lazy_bind_size);
+ }
+ if (DyLdInfoCommand.export_off) {
+ assert((DyLdInfoCommand.export_size == O.Exports.Trie.size()) &&
+ "Incorrect trie size");
+ Ends.push_back(DyLdInfoCommand.export_off + DyLdInfoCommand.export_size);
+ }
+ }
+
+ // Otherwise, use the last section / reloction.
+ for (const auto &LC : O.LoadCommands)
+ for (const auto &S : LC.Sections) {
+ Ends.push_back(S.Offset + S.Size);
+ if (S.RelOff)
+ Ends.push_back(S.RelOff +
+ S.NReloc * sizeof(MachO::any_relocation_info));
+ }
+
+ if (!Ends.empty())
+ return *std::max_element(Ends.begin(), Ends.end());
+
+ // Otherwise, we have only Mach header and load commands.
+ return headerSize() + loadCommandsSize();
+}
+
+void MachOWriter::writeHeader() {
+ MachO::mach_header_64 Header;
+
+ Header.magic = O.Header.Magic;
+ Header.cputype = O.Header.CPUType;
+ Header.cpusubtype = O.Header.CPUSubType;
+ Header.filetype = O.Header.FileType;
+ Header.ncmds = O.Header.NCmds;
+ Header.sizeofcmds = O.Header.SizeOfCmds;
+ Header.flags = O.Header.Flags;
+ Header.reserved = O.Header.Reserved;
+
+ if (IsLittleEndian != sys::IsLittleEndianHost)
+ MachO::swapStruct(Header);
+
+ auto HeaderSize =
+ Is64Bit ? sizeof(MachO::mach_header_64) : sizeof(MachO::mach_header);
+ memcpy(B.getBufferStart(), &Header, HeaderSize);
+}
+
+void MachOWriter::writeLoadCommands() {
+ uint8_t *Begin = B.getBufferStart() + headerSize();
+ MachO::macho_load_command MLC;
+ for (const auto &LC : O.LoadCommands) {
+#define HANDLE_LOAD_COMMAND(LCName, LCValue, LCStruct) \
+ case MachO::LCName: \
+ assert(sizeof(MachO::LCStruct) + LC.Payload.size() == \
+ LC.MachOLoadCommand.load_command_data.cmdsize); \
+ MLC = LC.MachOLoadCommand; \
+ if (IsLittleEndian != sys::IsLittleEndianHost) \
+ MachO::swapStruct(MLC.LCStruct##_data); \
+ memcpy(Begin, &MLC.LCStruct##_data, sizeof(MachO::LCStruct)); \
+ Begin += sizeof(MachO::LCStruct); \
+ memcpy(Begin, LC.Payload.data(), LC.Payload.size()); \
+ Begin += LC.Payload.size(); \
+ break;
+
+ switch (LC.MachOLoadCommand.load_command_data.cmd) {
+ default:
+ assert(sizeof(MachO::load_command) + LC.Payload.size() ==
+ LC.MachOLoadCommand.load_command_data.cmdsize);
+ MLC = LC.MachOLoadCommand;
+ if (IsLittleEndian != sys::IsLittleEndianHost)
+ MachO::swapStruct(MLC.load_command_data);
+ memcpy(Begin, &MLC.load_command_data, sizeof(MachO::load_command));
+ Begin += sizeof(MachO::load_command);
+ memcpy(Begin, LC.Payload.data(), LC.Payload.size());
+ Begin += LC.Payload.size();
+ break;
+#include "llvm/BinaryFormat/MachO.def"
+ }
+ }
+}
+
+void MachOWriter::writeSections() {
+ for (const auto &LC : O.LoadCommands)
+ for (const auto &Sec : LC.Sections) {
+ assert(Sec.Offset && "Section offset can not be zero");
+ assert((Sec.Size == Sec.Content.size()) && "Incorrect section size");
+ memcpy(B.getBufferStart() + Sec.Offset, Sec.Content.data(),
+ Sec.Content.size());
+ for (size_t Index = 0; Index < Sec.Relocations.size(); ++Index) {
+ MachO::any_relocation_info R = Sec.Relocations[Index];
+ if (IsLittleEndian != sys::IsLittleEndianHost)
+ MachO::swapStruct(R);
+ memcpy(B.getBufferStart() + Sec.RelOff +
+ Index * sizeof(MachO::any_relocation_info),
+ &R, sizeof(R));
+ }
+ }
+}
+
+template <typename NListType>
+void writeNListEntry(const NListEntry &NLE, bool IsLittleEndian, char *&Out) {
+ NListType ListEntry;
+ ListEntry.n_strx = NLE.n_strx;
+ ListEntry.n_type = NLE.n_type;
+ ListEntry.n_sect = NLE.n_sect;
+ ListEntry.n_desc = NLE.n_desc;
+ ListEntry.n_value = NLE.n_value;
+
+ if (IsLittleEndian != sys::IsLittleEndianHost)
+ MachO::swapStruct(ListEntry);
+ memcpy(Out, reinterpret_cast<const char *>(&ListEntry), sizeof(NListType));
+ Out += sizeof(NListType);
+}
+
+void MachOWriter::writeSymbolTable() {
+ if (!O.SymTabCommandIndex)
+ return;
+ const MachO::symtab_command &SymTabCommand =
+ O.LoadCommands[*O.SymTabCommandIndex]
+ .MachOLoadCommand.symtab_command_data;
+ assert((SymTabCommand.nsyms == O.SymTable.NameList.size()) &&
+ "Incorrect number of symbols");
+ char *Out = (char *)B.getBufferStart() + SymTabCommand.symoff;
+ for (auto NLE : O.SymTable.NameList) {
+ if (Is64Bit)
+ writeNListEntry<MachO::nlist_64>(NLE, IsLittleEndian, Out);
+ else
+ writeNListEntry<MachO::nlist>(NLE, IsLittleEndian, Out);
+ }
+}
+
+void MachOWriter::writeStringTable() {
+ if (!O.SymTabCommandIndex)
+ return;
+ const MachO::symtab_command &SymTabCommand =
+ O.LoadCommands[*O.SymTabCommandIndex]
+ .MachOLoadCommand.symtab_command_data;
+ char *Out = (char *)B.getBufferStart() + SymTabCommand.stroff;
+ assert((SymTabCommand.strsize == strTableSize()) &&
+ "Incorrect string table size");
+ for (size_t Index = 0; Index < O.StrTable.Strings.size(); ++Index) {
+ memcpy(Out, O.StrTable.Strings[Index].data(),
+ O.StrTable.Strings[Index].size());
+ Out += O.StrTable.Strings[Index].size();
+ if (Index + 1 != O.StrTable.Strings.size()) {
+ memcpy(Out, "\0", 1);
+ Out += 1;
+ }
+ }
+}
+
+void MachOWriter::writeRebaseInfo() {
+ if (!O.DyLdInfoCommandIndex)
+ return;
+ const MachO::dyld_info_command &DyLdInfoCommand =
+ O.LoadCommands[*O.DyLdInfoCommandIndex]
+ .MachOLoadCommand.dyld_info_command_data;
+ char *Out = (char *)B.getBufferStart() + DyLdInfoCommand.rebase_off;
+ assert((DyLdInfoCommand.rebase_size == O.Rebases.Opcodes.size()) &&
+ "Incorrect rebase opcodes size");
+ memcpy(Out, O.Rebases.Opcodes.data(), O.Rebases.Opcodes.size());
+}
+
+void MachOWriter::writeBindInfo() {
+ if (!O.DyLdInfoCommandIndex)
+ return;
+ const MachO::dyld_info_command &DyLdInfoCommand =
+ O.LoadCommands[*O.DyLdInfoCommandIndex]
+ .MachOLoadCommand.dyld_info_command_data;
+ char *Out = (char *)B.getBufferStart() + DyLdInfoCommand.bind_off;
+ assert((DyLdInfoCommand.bind_size == O.Binds.Opcodes.size()) &&
+ "Incorrect bind opcodes size");
+ memcpy(Out, O.Binds.Opcodes.data(), O.Binds.Opcodes.size());
+}
+
+void MachOWriter::writeWeakBindInfo() {
+ if (!O.DyLdInfoCommandIndex)
+ return;
+ const MachO::dyld_info_command &DyLdInfoCommand =
+ O.LoadCommands[*O.DyLdInfoCommandIndex]
+ .MachOLoadCommand.dyld_info_command_data;
+ char *Out = (char *)B.getBufferStart() + DyLdInfoCommand.weak_bind_off;
+ assert((DyLdInfoCommand.weak_bind_size == O.WeakBinds.Opcodes.size()) &&
+ "Incorrect weak bind opcodes size");
+ memcpy(Out, O.WeakBinds.Opcodes.data(), O.WeakBinds.Opcodes.size());
+}
+
+void MachOWriter::writeLazyBindInfo() {
+ if (!O.DyLdInfoCommandIndex)
+ return;
+ const MachO::dyld_info_command &DyLdInfoCommand =
+ O.LoadCommands[*O.DyLdInfoCommandIndex]
+ .MachOLoadCommand.dyld_info_command_data;
+ char *Out = (char *)B.getBufferStart() + DyLdInfoCommand.lazy_bind_off;
+ assert((DyLdInfoCommand.lazy_bind_size == O.LazyBinds.Opcodes.size()) &&
+ "Incorrect lazy bind opcodes size");
+ memcpy(Out, O.LazyBinds.Opcodes.data(), O.LazyBinds.Opcodes.size());
+}
+
+void MachOWriter::writeExportInfo() {
+ if (!O.DyLdInfoCommandIndex)
+ return;
+ const MachO::dyld_info_command &DyLdInfoCommand =
+ O.LoadCommands[*O.DyLdInfoCommandIndex]
+ .MachOLoadCommand.dyld_info_command_data;
+ char *Out = (char *)B.getBufferStart() + DyLdInfoCommand.export_off;
+ assert((DyLdInfoCommand.export_size == O.Exports.Trie.size()) &&
+ "Incorrect export trie size");
+ memcpy(Out, O.Exports.Trie.data(), O.Exports.Trie.size());
+}
+
+void MachOWriter::writeTail() {
+ typedef void (MachOWriter::*WriteHandlerType)(void);
+ typedef std::pair<uint64_t, WriteHandlerType> WriteOperation;
+ SmallVector<WriteOperation, 7> Queue;
+
+ if (O.SymTabCommandIndex) {
+ const MachO::symtab_command &SymTabCommand =
+ O.LoadCommands[*O.SymTabCommandIndex]
+ .MachOLoadCommand.symtab_command_data;
+ if (SymTabCommand.symoff)
+ Queue.push_back({SymTabCommand.symoff, &MachOWriter::writeSymbolTable});
+ if (SymTabCommand.stroff)
+ Queue.push_back({SymTabCommand.stroff, &MachOWriter::writeStringTable});
+ }
+
+ if (O.DyLdInfoCommandIndex) {
+ const MachO::dyld_info_command &DyLdInfoCommand =
+ O.LoadCommands[*O.DyLdInfoCommandIndex]
+ .MachOLoadCommand.dyld_info_command_data;
+ if (DyLdInfoCommand.rebase_off)
+ Queue.push_back(
+ {DyLdInfoCommand.rebase_off, &MachOWriter::writeRebaseInfo});
+ if (DyLdInfoCommand.bind_off)
+ Queue.push_back({DyLdInfoCommand.bind_off, &MachOWriter::writeBindInfo});
+ if (DyLdInfoCommand.weak_bind_off)
+ Queue.push_back(
+ {DyLdInfoCommand.weak_bind_off, &MachOWriter::writeWeakBindInfo});
+ if (DyLdInfoCommand.lazy_bind_off)
+ Queue.push_back(
+ {DyLdInfoCommand.lazy_bind_off, &MachOWriter::writeLazyBindInfo});
+ if (DyLdInfoCommand.export_off)
+ Queue.push_back(
+ {DyLdInfoCommand.export_off, &MachOWriter::writeExportInfo});
+ }
+
+ llvm::sort(Queue, [](const WriteOperation &LHS, const WriteOperation &RHS) {
+ return LHS.first < RHS.first;
+ });
+
+ for (auto WriteOp : Queue)
+ (this->*WriteOp.second)();
+}
+
+Error MachOWriter::write() {
+ if (Error E = B.allocate(totalSize()))
+ return E;
+ memset(B.getBufferStart(), 0, totalSize());
+ writeHeader();
+ writeLoadCommands();
+ writeSections();
+ writeTail();
+ if (auto E = B.commit())
+ return E;
+ return Error::success();
+}
+
+} // end namespace macho
+} // end namespace objcopy
+} // end namespace llvm