398 lines
13 KiB
C++
398 lines
13 KiB
C++
//===- MachOObject.cpp - Mach-O Object File Wrapper -----------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Object/MachOObject.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Support/DataExtractor.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/Host.h"
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#include "llvm/Support/MemoryBuffer.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Support/SwapByteOrder.h"
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using namespace llvm;
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using namespace llvm::object;
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/* Translation Utilities */
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template<typename T>
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static void SwapValue(T &Value) {
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Value = sys::SwapByteOrder(Value);
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}
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template<typename T>
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static void SwapStruct(T &Value);
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template<typename T>
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static void ReadInMemoryStruct(const MachOObject &MOO,
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StringRef Buffer, uint64_t Base,
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InMemoryStruct<T> &Res) {
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typedef T struct_type;
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uint64_t Size = sizeof(struct_type);
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// Check that the buffer contains the expected data.
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if (Base + Size > Buffer.size()) {
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Res = 0;
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return;
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}
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// Check whether we can return a direct pointer.
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struct_type *Ptr = (struct_type *) (Buffer.data() + Base);
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if (!MOO.isSwappedEndian()) {
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Res = Ptr;
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return;
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}
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// Otherwise, copy the struct and translate the values.
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Res = *Ptr;
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SwapStruct(*Res);
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}
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/* *** */
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MachOObject::MachOObject(MemoryBuffer *Buffer_, bool IsLittleEndian_,
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bool Is64Bit_)
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: Buffer(Buffer_), IsLittleEndian(IsLittleEndian_), Is64Bit(Is64Bit_),
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IsSwappedEndian(IsLittleEndian != sys::isLittleEndianHost()),
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HasStringTable(false), LoadCommands(0), NumLoadedCommands(0) {
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// Load the common header.
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memcpy(&Header, Buffer->getBuffer().data(), sizeof(Header));
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if (IsSwappedEndian) {
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SwapValue(Header.Magic);
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SwapValue(Header.CPUType);
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SwapValue(Header.CPUSubtype);
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SwapValue(Header.FileType);
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SwapValue(Header.NumLoadCommands);
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SwapValue(Header.SizeOfLoadCommands);
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SwapValue(Header.Flags);
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}
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if (is64Bit()) {
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memcpy(&Header64Ext, Buffer->getBuffer().data() + sizeof(Header),
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sizeof(Header64Ext));
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if (IsSwappedEndian) {
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SwapValue(Header64Ext.Reserved);
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}
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}
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// Create the load command array if sane.
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if (getHeader().NumLoadCommands < (1 << 20))
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LoadCommands = new LoadCommandInfo[getHeader().NumLoadCommands];
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}
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MachOObject::~MachOObject() {
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delete [] LoadCommands;
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}
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MachOObject *MachOObject::LoadFromBuffer(MemoryBuffer *Buffer,
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std::string *ErrorStr) {
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// First, check the magic value and initialize the basic object info.
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bool IsLittleEndian = false, Is64Bit = false;
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StringRef Magic = Buffer->getBuffer().slice(0, 4);
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if (Magic == "\xFE\xED\xFA\xCE") {
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} else if (Magic == "\xCE\xFA\xED\xFE") {
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IsLittleEndian = true;
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} else if (Magic == "\xFE\xED\xFA\xCF") {
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Is64Bit = true;
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} else if (Magic == "\xCF\xFA\xED\xFE") {
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IsLittleEndian = true;
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Is64Bit = true;
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} else {
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if (ErrorStr) *ErrorStr = "not a Mach object file (invalid magic)";
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return 0;
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}
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// Ensure that the at least the full header is present.
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unsigned HeaderSize = Is64Bit ? macho::Header64Size : macho::Header32Size;
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if (Buffer->getBufferSize() < HeaderSize) {
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if (ErrorStr) *ErrorStr = "not a Mach object file (invalid header)";
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return 0;
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}
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OwningPtr<MachOObject> Object(new MachOObject(Buffer, IsLittleEndian,
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Is64Bit));
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// Check for bogus number of load commands.
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if (Object->getHeader().NumLoadCommands >= (1 << 20)) {
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if (ErrorStr) *ErrorStr = "not a Mach object file (unreasonable header)";
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return 0;
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}
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if (ErrorStr) *ErrorStr = "";
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return Object.take();
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}
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StringRef MachOObject::getData(size_t Offset, size_t Size) const {
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return Buffer->getBuffer().substr(Offset,Size);
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}
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void MachOObject::RegisterStringTable(macho::SymtabLoadCommand &SLC) {
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HasStringTable = true;
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StringTable = Buffer->getBuffer().substr(SLC.StringTableOffset,
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SLC.StringTableSize);
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}
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const MachOObject::LoadCommandInfo &
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MachOObject::getLoadCommandInfo(unsigned Index) const {
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assert(Index < getHeader().NumLoadCommands && "Invalid index!");
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// Load the command, if necessary.
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if (Index >= NumLoadedCommands) {
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uint64_t Offset;
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if (Index == 0) {
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Offset = getHeaderSize();
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} else {
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const LoadCommandInfo &Prev = getLoadCommandInfo(Index - 1);
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Offset = Prev.Offset + Prev.Command.Size;
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}
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LoadCommandInfo &Info = LoadCommands[Index];
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memcpy(&Info.Command, Buffer->getBuffer().data() + Offset,
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sizeof(macho::LoadCommand));
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if (IsSwappedEndian) {
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SwapValue(Info.Command.Type);
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SwapValue(Info.Command.Size);
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}
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Info.Offset = Offset;
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NumLoadedCommands = Index + 1;
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}
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return LoadCommands[Index];
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}
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template<>
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void SwapStruct(macho::SegmentLoadCommand &Value) {
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SwapValue(Value.Type);
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SwapValue(Value.Size);
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SwapValue(Value.VMAddress);
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SwapValue(Value.VMSize);
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SwapValue(Value.FileOffset);
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SwapValue(Value.FileSize);
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SwapValue(Value.MaxVMProtection);
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SwapValue(Value.InitialVMProtection);
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SwapValue(Value.NumSections);
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SwapValue(Value.Flags);
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}
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void MachOObject::ReadSegmentLoadCommand(const LoadCommandInfo &LCI,
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InMemoryStruct<macho::SegmentLoadCommand> &Res) const {
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ReadInMemoryStruct(*this, Buffer->getBuffer(), LCI.Offset, Res);
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}
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template<>
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void SwapStruct(macho::Segment64LoadCommand &Value) {
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SwapValue(Value.Type);
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SwapValue(Value.Size);
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SwapValue(Value.VMAddress);
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SwapValue(Value.VMSize);
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SwapValue(Value.FileOffset);
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SwapValue(Value.FileSize);
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SwapValue(Value.MaxVMProtection);
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SwapValue(Value.InitialVMProtection);
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SwapValue(Value.NumSections);
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SwapValue(Value.Flags);
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}
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void MachOObject::ReadSegment64LoadCommand(const LoadCommandInfo &LCI,
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InMemoryStruct<macho::Segment64LoadCommand> &Res) const {
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ReadInMemoryStruct(*this, Buffer->getBuffer(), LCI.Offset, Res);
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}
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template<>
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void SwapStruct(macho::SymtabLoadCommand &Value) {
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SwapValue(Value.Type);
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SwapValue(Value.Size);
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SwapValue(Value.SymbolTableOffset);
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SwapValue(Value.NumSymbolTableEntries);
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SwapValue(Value.StringTableOffset);
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SwapValue(Value.StringTableSize);
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}
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void MachOObject::ReadSymtabLoadCommand(const LoadCommandInfo &LCI,
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InMemoryStruct<macho::SymtabLoadCommand> &Res) const {
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ReadInMemoryStruct(*this, Buffer->getBuffer(), LCI.Offset, Res);
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}
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template<>
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void SwapStruct(macho::DysymtabLoadCommand &Value) {
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SwapValue(Value.Type);
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SwapValue(Value.Size);
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SwapValue(Value.LocalSymbolsIndex);
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SwapValue(Value.NumLocalSymbols);
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SwapValue(Value.ExternalSymbolsIndex);
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SwapValue(Value.NumExternalSymbols);
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SwapValue(Value.UndefinedSymbolsIndex);
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SwapValue(Value.NumUndefinedSymbols);
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SwapValue(Value.TOCOffset);
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SwapValue(Value.NumTOCEntries);
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SwapValue(Value.ModuleTableOffset);
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SwapValue(Value.NumModuleTableEntries);
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SwapValue(Value.ReferenceSymbolTableOffset);
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SwapValue(Value.NumReferencedSymbolTableEntries);
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SwapValue(Value.IndirectSymbolTableOffset);
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SwapValue(Value.NumIndirectSymbolTableEntries);
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SwapValue(Value.ExternalRelocationTableOffset);
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SwapValue(Value.NumExternalRelocationTableEntries);
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SwapValue(Value.LocalRelocationTableOffset);
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SwapValue(Value.NumLocalRelocationTableEntries);
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}
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void MachOObject::ReadDysymtabLoadCommand(const LoadCommandInfo &LCI,
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InMemoryStruct<macho::DysymtabLoadCommand> &Res) const {
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ReadInMemoryStruct(*this, Buffer->getBuffer(), LCI.Offset, Res);
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}
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template<>
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void SwapStruct(macho::LinkeditDataLoadCommand &Value) {
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SwapValue(Value.Type);
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SwapValue(Value.Size);
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SwapValue(Value.DataOffset);
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SwapValue(Value.DataSize);
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}
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void MachOObject::ReadLinkeditDataLoadCommand(const LoadCommandInfo &LCI,
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InMemoryStruct<macho::LinkeditDataLoadCommand> &Res) const {
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ReadInMemoryStruct(*this, Buffer->getBuffer(), LCI.Offset, Res);
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}
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template<>
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void SwapStruct(macho::IndirectSymbolTableEntry &Value) {
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SwapValue(Value.Index);
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}
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void
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MachOObject::ReadIndirectSymbolTableEntry(const macho::DysymtabLoadCommand &DLC,
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unsigned Index,
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InMemoryStruct<macho::IndirectSymbolTableEntry> &Res) const {
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uint64_t Offset = (DLC.IndirectSymbolTableOffset +
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Index * sizeof(macho::IndirectSymbolTableEntry));
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ReadInMemoryStruct(*this, Buffer->getBuffer(), Offset, Res);
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}
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template<>
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void SwapStruct(macho::Section &Value) {
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SwapValue(Value.Address);
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SwapValue(Value.Size);
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SwapValue(Value.Offset);
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SwapValue(Value.Align);
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SwapValue(Value.RelocationTableOffset);
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SwapValue(Value.NumRelocationTableEntries);
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SwapValue(Value.Flags);
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SwapValue(Value.Reserved1);
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SwapValue(Value.Reserved2);
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}
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void MachOObject::ReadSection(const LoadCommandInfo &LCI,
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unsigned Index,
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InMemoryStruct<macho::Section> &Res) const {
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assert(LCI.Command.Type == macho::LCT_Segment &&
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"Unexpected load command info!");
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uint64_t Offset = (LCI.Offset + sizeof(macho::SegmentLoadCommand) +
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Index * sizeof(macho::Section));
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ReadInMemoryStruct(*this, Buffer->getBuffer(), Offset, Res);
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}
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template<>
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void SwapStruct(macho::Section64 &Value) {
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SwapValue(Value.Address);
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SwapValue(Value.Size);
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SwapValue(Value.Offset);
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SwapValue(Value.Align);
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SwapValue(Value.RelocationTableOffset);
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SwapValue(Value.NumRelocationTableEntries);
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SwapValue(Value.Flags);
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SwapValue(Value.Reserved1);
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SwapValue(Value.Reserved2);
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SwapValue(Value.Reserved3);
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}
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void MachOObject::ReadSection64(const LoadCommandInfo &LCI,
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unsigned Index,
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InMemoryStruct<macho::Section64> &Res) const {
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assert(LCI.Command.Type == macho::LCT_Segment64 &&
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"Unexpected load command info!");
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uint64_t Offset = (LCI.Offset + sizeof(macho::Segment64LoadCommand) +
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Index * sizeof(macho::Section64));
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ReadInMemoryStruct(*this, Buffer->getBuffer(), Offset, Res);
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}
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template<>
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void SwapStruct(macho::RelocationEntry &Value) {
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SwapValue(Value.Word0);
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SwapValue(Value.Word1);
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}
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void MachOObject::ReadRelocationEntry(uint64_t RelocationTableOffset,
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unsigned Index,
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InMemoryStruct<macho::RelocationEntry> &Res) const {
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uint64_t Offset = (RelocationTableOffset +
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Index * sizeof(macho::RelocationEntry));
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ReadInMemoryStruct(*this, Buffer->getBuffer(), Offset, Res);
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}
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template<>
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void SwapStruct(macho::SymbolTableEntry &Value) {
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SwapValue(Value.StringIndex);
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SwapValue(Value.Flags);
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SwapValue(Value.Value);
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}
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void MachOObject::ReadSymbolTableEntry(uint64_t SymbolTableOffset,
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unsigned Index,
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InMemoryStruct<macho::SymbolTableEntry> &Res) const {
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uint64_t Offset = (SymbolTableOffset +
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Index * sizeof(macho::SymbolTableEntry));
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ReadInMemoryStruct(*this, Buffer->getBuffer(), Offset, Res);
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}
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template<>
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void SwapStruct(macho::Symbol64TableEntry &Value) {
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SwapValue(Value.StringIndex);
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SwapValue(Value.Flags);
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SwapValue(Value.Value);
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}
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void MachOObject::ReadSymbol64TableEntry(uint64_t SymbolTableOffset,
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unsigned Index,
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InMemoryStruct<macho::Symbol64TableEntry> &Res) const {
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uint64_t Offset = (SymbolTableOffset +
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Index * sizeof(macho::Symbol64TableEntry));
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ReadInMemoryStruct(*this, Buffer->getBuffer(), Offset, Res);
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}
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void MachOObject::ReadULEB128s(uint64_t Index,
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SmallVectorImpl<uint64_t> &Out) const {
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DataExtractor extractor(Buffer->getBuffer(), true, 0);
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uint32_t offset = Index;
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uint64_t data = 0;
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while (uint64_t delta = extractor.getULEB128(&offset)) {
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data += delta;
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Out.push_back(data);
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}
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}
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/* ** */
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// Object Dumping Facilities
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void MachOObject::dump() const { print(dbgs()); dbgs() << '\n'; }
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void MachOObject::dumpHeader() const { printHeader(dbgs()); dbgs() << '\n'; }
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void MachOObject::printHeader(raw_ostream &O) const {
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O << "('cputype', " << Header.CPUType << ")\n";
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O << "('cpusubtype', " << Header.CPUSubtype << ")\n";
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O << "('filetype', " << Header.FileType << ")\n";
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O << "('num_load_commands', " << Header.NumLoadCommands << ")\n";
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O << "('load_commands_size', " << Header.SizeOfLoadCommands << ")\n";
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O << "('flag', " << Header.Flags << ")\n";
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// Print extended header if 64-bit.
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if (is64Bit())
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O << "('reserved', " << Header64Ext.Reserved << ")\n";
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}
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void MachOObject::print(raw_ostream &O) const {
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O << "Header:\n";
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printHeader(O);
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O << "Load Commands:\n";
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O << "Buffer:\n";
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}
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