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//===- yaml2macho - Convert YAML to a Mach object file --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief The Mach component of yaml2obj.
///
//===----------------------------------------------------------------------===//
#include "yaml2obj.h"
#include "llvm/ObjectYAML/MachOYAML.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/MachO.h"
#include "llvm/Support/YAMLTraits.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
namespace {
class MachOWriter {
public:
MachOWriter(MachOYAML::Object &Obj) : Obj(Obj) {
is64Bit = Obj.Header.magic == MachO::MH_MAGIC_64 ||
Obj.Header.magic == MachO::MH_CIGAM_64;
memset(reinterpret_cast<void *>(&Header64), 0,
sizeof(MachO::mach_header_64));
assert((is64Bit || Obj.Header.reserved == 0xDEADBEEFu) &&
"32-bit MachO has reserved in header");
assert((!is64Bit || Obj.Header.reserved != 0xDEADBEEFu) &&
"64-bit MachO has missing reserved in header");
}
Error writeMachO(raw_ostream &OS);
private:
Error writeHeader(raw_ostream &OS);
Error writeLoadCommands(raw_ostream &OS);
MachOYAML::Object &Obj;
bool is64Bit;
union {
MachO::mach_header_64 Header64;
MachO::mach_header Header;
};
};
Error MachOWriter::writeMachO(raw_ostream &OS) {
if (auto Err = writeHeader(OS))
return Err;
if (auto Err = writeLoadCommands(OS))
return Err;
return Error::success();
}
Error MachOWriter::writeHeader(raw_ostream &OS) {
Header.magic = Obj.Header.magic;
Header.cputype = Obj.Header.cputype;
Header.cpusubtype = Obj.Header.cpusubtype;
Header.filetype = Obj.Header.filetype;
Header.ncmds = Obj.Header.ncmds;
Header.sizeofcmds = Obj.Header.sizeofcmds;
Header.flags = Obj.Header.flags;
Header64.reserved = Obj.Header.reserved;
if (is64Bit)
OS.write((const char *)&Header64, sizeof(MachO::mach_header_64));
else
OS.write((const char *)&Header, sizeof(MachO::mach_header));
return Error::success();
}
template <typename SectionType>
SectionType constructSection(MachOYAML::Section Sec) {
SectionType TempSec;
memcpy(reinterpret_cast<void *>(&TempSec.sectname[0]), &Sec.sectname[0], 16);
memcpy(reinterpret_cast<void *>(&TempSec.segname[0]), &Sec.segname[0], 16);
TempSec.addr = Sec.addr;
TempSec.size = Sec.size;
TempSec.offset = Sec.offset;
TempSec.align = Sec.align;
TempSec.reloff = Sec.reloff;
TempSec.nreloc = Sec.nreloc;
TempSec.flags = Sec.flags;
TempSec.reserved1 = Sec.reserved1;
TempSec.reserved2 = Sec.reserved2;
return TempSec;
}
Error MachOWriter::writeLoadCommands(raw_ostream &OS) {
for (auto &LC : Obj.LoadCommands) {
size_t BytesWritten = 0;
#define HANDLE_LOAD_COMMAND(LCName, LCValue, LCStruct) \
case MachO::LCName: \
OS.write(reinterpret_cast<const char *>(&(LC.Data.LCStruct##_data)), \
sizeof(MachO::LCStruct)); \
BytesWritten = sizeof(MachO::LCStruct); \
break;
switch (LC.Data.load_command_data.cmd) {
default:
OS.write(reinterpret_cast<const char *>(&(LC.Data.load_command_data)),
sizeof(MachO::load_command));
BytesWritten = sizeof(MachO::load_command);
break;
#include "llvm/Support/MachO.def"
}
if(LC.Data.load_command_data.cmd == MachO::LC_SEGMENT) {
for(auto Sec : LC.Sections) {
auto TempSec = constructSection<MachO::section>(Sec);
OS.write(reinterpret_cast<const char *>(&(TempSec)), sizeof(MachO::section));
BytesWritten += sizeof(MachO::section);
}
} else if(LC.Data.load_command_data.cmd == MachO::LC_SEGMENT_64) {
for(auto Sec : LC.Sections) {
auto TempSec = constructSection<MachO::section_64>(Sec);
TempSec.reserved3 = Sec.reserved3;
OS.write(reinterpret_cast<const char *>(&(TempSec)), sizeof(MachO::section_64));
BytesWritten += sizeof(MachO::section_64);
}
}
auto BytesRemaining =
LC.Data.load_command_data.cmdsize - BytesWritten;
if (BytesRemaining > 0) {
// TODO: Replace all this once the load command data is present in yaml.
// For now I fill with 0xDEADBEEF because it is easy to spot on a hex
// viewer.
std::vector<uint32_t> FillData;
FillData.insert(FillData.begin(), BytesRemaining / 4 + 1, 0xDEADBEEFu);
OS.write(reinterpret_cast<char *>(FillData.data()), BytesRemaining);
}
}
return Error::success();
}
} // end anonymous namespace
int yaml2macho(yaml::Input &YIn, raw_ostream &Out) {
MachOYAML::Object Doc;
YIn >> Doc;
if (YIn.error()) {
errs() << "yaml2obj: Failed to parse YAML file!\n";
return 1;
}
MachOWriter Writer(Doc);
if (auto Err = Writer.writeMachO(Out)) {
errs() << toString(std::move(Err));
return 1;
}
return 0;
}
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