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llvm-project/llvm/lib/Object/MachOUniversalWriter.cpp

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//===- MachOUniversalWriter.cpp - MachO universal binary writer---*- C++-*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Defines the Slice class and writeUniversalBinary function for writing a MachO
// universal binary file.
//
//===----------------------------------------------------------------------===//
#include "llvm/Object/MachOUniversalWriter.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Object/Archive.h"
#include "llvm/Object/Binary.h"
#include "llvm/Object/Error.h"
#include "llvm/Object/IRObjectFile.h"
#include "llvm/Object/MachO.h"
#include "llvm/Object/MachOUniversal.h"
#include "llvm/Support/FileOutputBuffer.h"
using namespace llvm;
using namespace object;
// For compatibility with cctools lipo, a file's alignment is calculated as the
// minimum aligment of all segments. For object files, the file's alignment is
// the maximum alignment of its sections.
static uint32_t calculateFileAlignment(const MachOObjectFile &O) {
uint32_t P2CurrentAlignment;
uint32_t P2MinAlignment = MachOUniversalBinary::MaxSectionAlignment;
const bool Is64Bit = O.is64Bit();
for (const auto &LC : O.load_commands()) {
if (LC.C.cmd != (Is64Bit ? MachO::LC_SEGMENT_64 : MachO::LC_SEGMENT))
continue;
if (O.getHeader().filetype == MachO::MH_OBJECT) {
unsigned NumberOfSections =
(Is64Bit ? O.getSegment64LoadCommand(LC).nsects
: O.getSegmentLoadCommand(LC).nsects);
P2CurrentAlignment = NumberOfSections ? 2 : P2MinAlignment;
for (unsigned SI = 0; SI < NumberOfSections; ++SI) {
P2CurrentAlignment = std::max(P2CurrentAlignment,
(Is64Bit ? O.getSection64(LC, SI).align
: O.getSection(LC, SI).align));
}
} else {
P2CurrentAlignment =
countTrailingZeros(Is64Bit ? O.getSegment64LoadCommand(LC).vmaddr
: O.getSegmentLoadCommand(LC).vmaddr);
}
P2MinAlignment = std::min(P2MinAlignment, P2CurrentAlignment);
}
// return a value >= 4 byte aligned, and less than MachO MaxSectionAlignment
return std::max(
static_cast<uint32_t>(2),
std::min(P2MinAlignment, static_cast<uint32_t>(
MachOUniversalBinary::MaxSectionAlignment)));
}
static uint32_t calculateAlignment(const MachOObjectFile &ObjectFile) {
switch (ObjectFile.getHeader().cputype) {
case MachO::CPU_TYPE_I386:
case MachO::CPU_TYPE_X86_64:
case MachO::CPU_TYPE_POWERPC:
case MachO::CPU_TYPE_POWERPC64:
return 12; // log2 value of page size(4k) for x86 and PPC
case MachO::CPU_TYPE_ARM:
case MachO::CPU_TYPE_ARM64:
case MachO::CPU_TYPE_ARM64_32:
return 14; // log2 value of page size(16k) for Darwin ARM
default:
return calculateFileAlignment(ObjectFile);
}
}
Slice::Slice(const MachOObjectFile &O, uint32_t Align)
: B(&O), CPUType(O.getHeader().cputype),
CPUSubType(O.getHeader().cpusubtype),
ArchName(std::string(O.getArchTriple().getArchName())),
P2Alignment(Align) {}
Slice::Slice(const IRObjectFile *IRO, uint32_t CPUType, uint32_t CPUSubType,
std::string ArchName, uint32_t Align)
: B(IRO), CPUType(CPUType), CPUSubType(CPUSubType),
ArchName(std::move(ArchName)), P2Alignment(Align) {}
Slice::Slice(const MachOObjectFile &O) : Slice(O, calculateAlignment(O)) {}
using MachoCPUTy = std::pair<unsigned, unsigned>;
static Expected<MachoCPUTy> getMachoCPUFromTriple(Triple TT) {
auto CPU = std::make_pair(MachO::getCPUType(TT), MachO::getCPUSubType(TT));
if (!CPU.first) {
return CPU.first.takeError();
}
if (!CPU.second) {
return CPU.second.takeError();
}
return std::make_pair(*CPU.first, *CPU.second);
}
static Expected<MachoCPUTy> getMachoCPUFromTriple(StringRef TT) {
return getMachoCPUFromTriple(Triple{TT});
}
Expected<Slice> Slice::create(const Archive *A, LLVMContext *LLVMCtx) {
Error Err = Error::success();
std::unique_ptr<MachOObjectFile> MFO = nullptr;
std::unique_ptr<IRObjectFile> IRFO = nullptr;
for (const Archive::Child &Child : A->children(Err)) {
Expected<std::unique_ptr<Binary>> ChildOrErr = Child.getAsBinary(LLVMCtx);
if (!ChildOrErr)
return createFileError(A->getFileName(), ChildOrErr.takeError());
Binary *Bin = ChildOrErr.get().get();
if (Bin->isMachOUniversalBinary())
return createStringError(std::errc::invalid_argument,
("archive member " + Bin->getFileName() +
" is a fat file (not allowed in an archive)")
.str()
.c_str());
if (Bin->isMachO()) {
MachOObjectFile *O = cast<MachOObjectFile>(Bin);
if (IRFO) {
return createStringError(
std::errc::invalid_argument,
"archive member %s is a MachO, while previous archive member "
"%s was an IR LLVM object",
O->getFileName().str().c_str(), IRFO->getFileName().str().c_str());
}
if (MFO &&
std::tie(MFO->getHeader().cputype, MFO->getHeader().cpusubtype) !=
std::tie(O->getHeader().cputype, O->getHeader().cpusubtype)) {
return createStringError(
std::errc::invalid_argument,
("archive member " + O->getFileName() + " cputype (" +
Twine(O->getHeader().cputype) + ") and cpusubtype(" +
Twine(O->getHeader().cpusubtype) +
") does not match previous archive members cputype (" +
Twine(MFO->getHeader().cputype) + ") and cpusubtype(" +
Twine(MFO->getHeader().cpusubtype) +
") (all members must match) " + MFO->getFileName())
.str()
.c_str());
}
if (!MFO) {
ChildOrErr.get().release();
MFO.reset(O);
}
} else if (Bin->isIR()) {
IRObjectFile *O = cast<IRObjectFile>(Bin);
if (MFO) {
return createStringError(std::errc::invalid_argument,
"archive member '%s' is an LLVM IR object, "
"while previous archive member "
"'%s' was a MachO",
O->getFileName().str().c_str(),
MFO->getFileName().str().c_str());
}
if (IRFO) {
Expected<MachoCPUTy> CPUO = getMachoCPUFromTriple(O->getTargetTriple());
Expected<MachoCPUTy> CPUFO =
getMachoCPUFromTriple(IRFO->getTargetTriple());
if (!CPUO)
return CPUO.takeError();
if (!CPUFO)
return CPUFO.takeError();
if (*CPUO != *CPUFO) {
return createStringError(
std::errc::invalid_argument,
("archive member " + O->getFileName() + " cputype (" +
Twine(CPUO->first) + ") and cpusubtype(" + Twine(CPUO->second) +
") does not match previous archive members cputype (" +
Twine(CPUFO->first) + ") and cpusubtype(" +
Twine(CPUFO->second) + ") (all members must match) " +
IRFO->getFileName())
.str()
.c_str());
}
} else {
ChildOrErr.get().release();
IRFO.reset(O);
}
} else
return createStringError(std::errc::invalid_argument,
("archive member " + Bin->getFileName() +
" is neither a MachO file or an LLVM IR file "
"(not allowed in an archive)")
.str()
.c_str());
}
if (Err)
return createFileError(A->getFileName(), std::move(Err));
if (!MFO && !IRFO)
return createStringError(
std::errc::invalid_argument,
("empty archive with no architecture specification: " +
A->getFileName() + " (can't determine architecture for it)")
.str()
.c_str());
if (MFO) {
Slice ArchiveSlice(*(MFO.get()), MFO->is64Bit() ? 3 : 2);
ArchiveSlice.B = A;
return ArchiveSlice;
}
// For IR objects
Expected<Slice> ArchiveSliceOrErr = Slice::create(IRFO.get(), 0);
if (!ArchiveSliceOrErr)
return createFileError(A->getFileName(), ArchiveSliceOrErr.takeError());
auto &ArchiveSlice = ArchiveSliceOrErr.get();
ArchiveSlice.B = A;
return Slice{std::move(ArchiveSlice)};
}
Expected<Slice> Slice::create(const IRObjectFile *IRO, uint32_t Align) {
Expected<MachoCPUTy> CPUOrErr = getMachoCPUFromTriple(IRO->getTargetTriple());
if (!CPUOrErr)
return CPUOrErr.takeError();
unsigned CPUType, CPUSubType;
std::tie(CPUType, CPUSubType) = CPUOrErr.get();
// We don't directly use the architecture name of the target triple T, as,
// for instance, thumb is treated as ARM by the MachOUniversal object.
std::string ArchName(
MachOObjectFile::getArchTriple(CPUType, CPUSubType).getArchName());
return Slice{IRO, CPUType, CPUSubType, std::move(ArchName), Align};
}
static Expected<SmallVector<MachO::fat_arch, 2>>
buildFatArchList(ArrayRef<Slice> Slices) {
SmallVector<MachO::fat_arch, 2> FatArchList;
uint64_t Offset =
sizeof(MachO::fat_header) + Slices.size() * sizeof(MachO::fat_arch);
for (const auto &S : Slices) {
Offset = alignTo(Offset, 1ull << S.getP2Alignment());
if (Offset > UINT32_MAX)
return createStringError(
std::errc::invalid_argument,
("fat file too large to be created because the offset "
"field in struct fat_arch is only 32-bits and the offset " +
Twine(Offset) + " for " + S.getBinary()->getFileName() +
" for architecture " + S.getArchString() + "exceeds that.")
.str()
.c_str());
MachO::fat_arch FatArch;
FatArch.cputype = S.getCPUType();
FatArch.cpusubtype = S.getCPUSubType();
FatArch.offset = Offset;
FatArch.size = S.getBinary()->getMemoryBufferRef().getBufferSize();
FatArch.align = S.getP2Alignment();
Offset += FatArch.size;
FatArchList.push_back(FatArch);
}
return FatArchList;
}
Error object::writeUniversalBinary(ArrayRef<Slice> Slices,
StringRef OutputFileName) {
MachO::fat_header FatHeader;
FatHeader.magic = MachO::FAT_MAGIC;
FatHeader.nfat_arch = Slices.size();
Expected<SmallVector<MachO::fat_arch, 2>> FatArchListOrErr =
buildFatArchList(Slices);
if (!FatArchListOrErr)
return FatArchListOrErr.takeError();
SmallVector<MachO::fat_arch, 2> FatArchList = *FatArchListOrErr;
const bool IsExecutable = any_of(Slices, [](Slice S) {
return sys::fs::can_execute(S.getBinary()->getFileName());
});
const uint64_t OutputFileSize =
static_cast<uint64_t>(FatArchList.back().offset) +
FatArchList.back().size;
Expected<std::unique_ptr<FileOutputBuffer>> OutFileOrError =
FileOutputBuffer::create(OutputFileName, OutputFileSize,
IsExecutable ? FileOutputBuffer::F_executable
: 0);
if (!OutFileOrError)
return createFileError(OutputFileName, OutFileOrError.takeError());
std::unique_ptr<FileOutputBuffer> OutFile = std::move(OutFileOrError.get());
std::memset(OutFile->getBufferStart(), 0, OutputFileSize);
if (sys::IsLittleEndianHost)
MachO::swapStruct(FatHeader);
std::memcpy(OutFile->getBufferStart(), &FatHeader, sizeof(MachO::fat_header));
for (size_t Index = 0, Size = Slices.size(); Index < Size; ++Index) {
MemoryBufferRef BufferRef = Slices[Index].getBinary()->getMemoryBufferRef();
std::copy(BufferRef.getBufferStart(), BufferRef.getBufferEnd(),
OutFile->getBufferStart() + FatArchList[Index].offset);
}
// FatArchs written after Slices in order to reduce the number of swaps for
// the LittleEndian case
if (sys::IsLittleEndianHost)
for (MachO::fat_arch &FA : FatArchList)
MachO::swapStruct(FA);
std::memcpy(OutFile->getBufferStart() + sizeof(MachO::fat_header),
FatArchList.begin(),
sizeof(MachO::fat_arch) * FatArchList.size());
if (Error E = OutFile->commit())
return createFileError(OutputFileName, std::move(E));
return Error::success();
}
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