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feature/stackanalysis
revng-revng/tools/revng-lift/BinaryFile.cpp
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Antonio Frighetto 9595894bcf BinaryFile: add architecture-dependent fields 
Add return address register and minimal final stack offset in Arch.
2021-12-10 12:30:11 +01:00

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/// \file BinaryFile.cpp
/// \brief
//
// This file is distributed under the MIT License. See LICENSE.md for details.
//
#include <memory>
#include <string>
#include <tuple>
#include <utility>
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/Object/COFF.h"
#include "llvm/Object/ELF.h"
#include "llvm/Object/MachO.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/LEB128.h"
#include "revng/Support/CommandLine.h"
#include "revng/Support/Debug.h"
#include "BinaryFile.h"
// using directives
using namespace llvm;
using std::make_pair;
using LabelList = BinaryFile::LabelList;
static Logger<> EhFrameLog("ehframe");
static Logger<> LabelsLog("labels");
const unsigned char R_MIPS_IMPLICIT_RELATIVE = 255;
namespace nooverflow {
template<typename T, typename U>
auto add(T LHS, U RHS) -> Optional<decltype(LHS + RHS)> {
using V = decltype(LHS + RHS);
V Result = LHS + RHS;
if (Result < LHS)
return {};
return Result;
}
} // namespace nooverflow
template<typename T>
static void logAddress(T &Logger, const char *Name, MetaAddress Address) {
if (Logger.isEnabled()) {
Logger << Name;
Address.dump(Logger);
Logger << DoLog;
}
}
template<typename T>
bool contains(const ArrayRef<T> &Container, const ArrayRef<T> &Contained) {
return (Container.begin() <= Contained.begin()
and Container.end() >= Contained.end());
}
template<typename R>
static void swapBytes(R &Value) {
swapStruct(Value);
}
template<>
void swapBytes<uint32_t>(uint32_t &Value) {
sys::swapByteOrder(Value);
}
template<typename T>
class ArrayRefReader {
private:
ArrayRef<T> Array;
const T *Cursor;
bool Swap;
public:
ArrayRefReader(ArrayRef<T> Array, bool Swap) :
Array(Array), Cursor(Array.begin()), Swap(Swap) {}
bool eof() const { return Cursor == Array.end(); }
template<typename R>
R read() {
revng_check(Cursor + sizeof(R) > Cursor);
revng_check(Cursor + sizeof(R) <= Array.end());
R Result;
memcpy(&Result, Cursor, sizeof(R));
if (Swap)
swapBytes<R>(Result);
Cursor += sizeof(R);
return Result;
}
};
static MetaAddress
getInitialPC(Triple::ArchType Arch, bool Swap, ArrayRef<uint8_t> Command) {
using namespace llvm::MachO;
ArrayRefReader<uint8_t> Reader(Command, Swap);
uint32_t Flavor = Reader.read<uint32_t>();
uint32_t Count = Reader.read<uint32_t>();
Optional<uint64_t> PC;
switch (Arch) {
case Triple::x86: {
switch (Flavor) {
case MachO::x86_THREAD_STATE32:
revng_check(Count == MachO::x86_THREAD_STATE32_COUNT);
PC = Reader.read<x86_thread_state32_t>().eip;
break;
case MachO::x86_THREAD_STATE:
revng_check(Count == MachO::x86_THREAD_STATE_COUNT);
PC = Reader.read<x86_thread_state_t>().uts.ts32.eip;
break;
default:
revng_abort();
}
revng_check(Reader.eof());
} break;
case Triple::x86_64: {
switch (Flavor) {
case MachO::x86_THREAD_STATE64:
revng_check(Count == MachO::x86_THREAD_STATE64_COUNT);
PC = Reader.read<x86_thread_state64_t>().rip;
break;
case MachO::x86_THREAD_STATE:
revng_check(Count == MachO::x86_THREAD_STATE_COUNT);
PC = Reader.read<x86_thread_state_t>().uts.ts64.rip;
break;
default:
revng_abort();
}
} break;
case Triple::arm: {
switch (Flavor) {
case MachO::ARM_THREAD_STATE:
revng_check(Count == MachO::ARM_THREAD_STATE_COUNT);
PC = Reader.read<arm_thread_state_t>().uts.ts32.pc;
break;
default:
revng_abort();
}
} break;
case Triple::aarch64: {
switch (Flavor) {
case MachO::ARM_THREAD_STATE64:
revng_check(Count == MachO::ARM_THREAD_STATE64_COUNT);
PC = Reader.read<arm_thread_state64_t>().pc;
break;
default:
revng_abort();
}
} break;
default:
revng_abort("Unexpected architecture for Mach-O");
break;
}
revng_check(Reader.eof());
if (PC)
return MetaAddress::fromPC(Arch, *PC);
else
return MetaAddress::invalid();
}
BinaryFile::BinaryFile(std::string FilePath, uint64_t PreferedBaseAddress) :
EntryPoint(MetaAddress::invalid()), BaseAddress(0) {
auto BinaryOrErr = object::createBinary(FilePath);
revng_check(BinaryOrErr, "Couldn't open the input file");
BinaryHandle = std::move(BinaryOrErr.get());
auto *TheBinary = cast<object::ObjectFile>(BinaryHandle.getBinary());
// TODO: QEMU should provide this information
uint32_t InstructionAlignment = 0;
StringRef SyscallHelper = "";
StringRef SyscallNumberRegister = "";
StringRef StackPointerRegister = "";
StringRef ReturnAddressRegister = "";
int64_t MinimalFinalStackOffset = 0;
ArrayRef<uint64_t> NoReturnSyscalls = {};
SmallVector<ABIRegister, 20> ABIRegisters;
uint32_t DelaySlotSize = 0;
unsigned PCMContextIndex = ABIRegister::NotInMContext;
llvm::StringRef WriteRegisterAsm = "";
llvm::StringRef ReadRegisterAsm = "";
llvm::StringRef JumpAsm = "";
bool HasRelocationAddend;
llvm::ArrayRef<const char> BasicBlockEndingPattern;
using RD = RelocationDescription;
using namespace llvm::ELF;
using namespace model::Register;
Architecture::RelocationTypesMap RelocationTypes;
model::abi::Values DefaultABI = model::abi::Invalid;
auto Arch = TheBinary->getArch();
switch (Arch) {
case Triple::x86:
InstructionAlignment = 1;
SyscallHelper = "helper_raise_interrupt";
SyscallNumberRegister = "eax";
StackPointerRegister = "esp";
MinimalFinalStackOffset = 4;
NoReturnSyscalls = {
0xfc, // exit_group
0x01, // exit
0x0b // execve
};
HasRelocationAddend = false;
RelocationTypes[R_386_RELATIVE] = RD(RD::BaseRelative, RD::TargetValue);
RelocationTypes[R_386_JUMP_SLOT] = RD(RD::SymbolRelative);
RelocationTypes[R_386_GLOB_DAT] = RD(RD::SymbolRelative);
RelocationTypes[R_386_32] = RD(RD::SymbolRelative, RD::TargetValue);
RelocationTypes[R_386_COPY] = RD(RD::LabelOnly, RD::TargetValue);
ABIRegisters = { { eax_x86 }, { ebx_x86 }, { ecx_x86 }, { edx_x86 },
{ esi_x86 }, { edi_x86 }, { ebp_x86 }, { esp_x86 } };
BasicBlockEndingPattern = "\xcc";
break;
case Triple::x86_64:
InstructionAlignment = 1;
SyscallHelper = "helper_syscall";
SyscallNumberRegister = "rax";
StackPointerRegister = "rsp";
MinimalFinalStackOffset = 8;
NoReturnSyscalls = {
0xe7, // exit_group
0x3c, // exit
0x3b // execve
};
PCMContextIndex = 0x10;
// The offsets associated to the registers have been obtained running the
// following command:
//
// scripts/compile-time-constants.py gcc ucontext.c
//
// where `ucontext.c` is:
//
// #define _GNU_SOURCE
// #include <sys/ucontext.h>
// #include <stdint.h>
//
// static ucontext_t UContext;
//
// #define REGISTER_OFFSET(reg) const int MContextIndex ## reg = REG_ ## reg
//
// REGISTER_OFFSET(R8);
// REGISTER_OFFSET(R9);
// REGISTER_OFFSET(R10);
// REGISTER_OFFSET(R11);
// REGISTER_OFFSET(R12);
// REGISTER_OFFSET(R13);
// REGISTER_OFFSET(R14);
// REGISTER_OFFSET(R15);
// REGISTER_OFFSET(RDI);
// REGISTER_OFFSET(RSI);
// REGISTER_OFFSET(RBP);
// REGISTER_OFFSET(RBX);
// REGISTER_OFFSET(RDX);
// REGISTER_OFFSET(RAX);
// REGISTER_OFFSET(RCX);
// REGISTER_OFFSET(RSP);
// REGISTER_OFFSET(RIP);
// TODO: here we're hardcoding the offsets in the QEMU struct
ABIRegisters = {
{ rax_x86_64, 0xD }, { rbx_x86_64, 0xB }, { rcx_x86_64, 0xE },
{ rdx_x86_64, 0xC }, { rbp_x86_64, 0xA }, { rsp_x86_64, 0xF },
{ rsi_x86_64, 0x9 }, { rdi_x86_64, 0x8 }, { r8_x86_64, 0x0 },
{ r9_x86_64, 0x1 }, { r10_x86_64, 0x2 }, { r11_x86_64, 0x3 },
{ r12_x86_64, 0x4 }, { r13_x86_64, 0x5 }, { r14_x86_64, 0x6 },
{ r15_x86_64, 0x7 }, { xmm0_x86_64 }, { xmm1_x86_64 },
{ xmm2_x86_64 }, { xmm3_x86_64 }, { xmm4_x86_64 },
{ xmm5_x86_64 }, { xmm6_x86_64 }, { xmm7_x86_64 }
};
WriteRegisterAsm = "movq $0, %REGISTER";
ReadRegisterAsm = "movq %REGISTER, $0";
JumpAsm = "jmpq *$0";
HasRelocationAddend = true;
RelocationTypes[R_X86_64_RELATIVE] = RD(RD::BaseRelative, RD::Addend);
RelocationTypes[R_X86_64_JUMP_SLOT] = RD(RD::SymbolRelative);
RelocationTypes[R_X86_64_GLOB_DAT] = RD(RD::SymbolRelative);
RelocationTypes[R_X86_64_COPY] = RD(RD::LabelOnly, RD::TargetValue);
// TODO: encode relocation size
RelocationTypes[R_X86_64_32] = RD(RD::SymbolRelative, RD::Addend);
RelocationTypes[R_X86_64_64] = RD(RD::SymbolRelative, RD::Addend);
BasicBlockEndingPattern = "\xcc";
DefaultABI = model::abi::SystemV_x86_64;
break;
case Triple::arm:
InstructionAlignment = 4;
SyscallHelper = "helper_exception_with_syndrome";
SyscallNumberRegister = "r7";
StackPointerRegister = "r13";
ReturnAddressRegister = "r14";
NoReturnSyscalls = {
0xf8, // exit_group
0x1, // exit
0xb // execve
};
ABIRegisters = { { r0_arm }, { r1_arm }, { r2_arm }, { r3_arm },
{ r4_arm }, { r5_arm }, { r6_arm }, { r7_arm },
{ r8_arm }, { r9_arm }, { r10_arm }, { r11_arm },
{ r12_arm }, { r13_arm }, { r14_arm } };
PCMContextIndex = 18;
HasRelocationAddend = false;
RelocationTypes[R_ARM_RELATIVE] = RD(RD::BaseRelative, RD::TargetValue);
RelocationTypes[R_ARM_JUMP_SLOT] = RD(RD::SymbolRelative);
RelocationTypes[R_ARM_GLOB_DAT] = RD(RD::SymbolRelative);
RelocationTypes[R_ARM_COPY] = RD(RD::LabelOnly, RD::TargetValue);
// bx lr
BasicBlockEndingPattern = "\x1e\xff\x2f\xe1";
break;
case Triple::aarch64:
HasRelocationAddend = false;
InstructionAlignment = 4;
SyscallHelper = "helper_exception_with_syndrome";
SyscallNumberRegister = "x8";
StackPointerRegister = "sp";
ReturnAddressRegister = "lr";
NoReturnSyscalls = {
0x5e, // exit_group
0x5d, // exit
0xdd // execve
};
ABIRegisters = {
{ x0_aarch64 }, { x1_aarch64 }, { x2_aarch64 }, { x3_aarch64 },
{ x4_aarch64 }, { x5_aarch64 }, { x6_aarch64 }, { x7_aarch64 },
{ x8_aarch64 }, { x9_aarch64 }, { x10_aarch64 }, { x11_aarch64 },
{ x12_aarch64 }, { x13_aarch64 }, { x14_aarch64 }, { x15_aarch64 },
{ x16_aarch64 }, { x17_aarch64 }, { x18_aarch64 }, { x19_aarch64 },
{ x20_aarch64 }, { x21_aarch64 }, { x22_aarch64 }, { x23_aarch64 },
{ x24_aarch64 }, { x25_aarch64 }, { x26_aarch64 }, { x27_aarch64 },
{ x28_aarch64 }, { x29_aarch64 }, { lr_aarch64 }, { sp_aarch64 }
};
HasRelocationAddend = false;
// ret
BasicBlockEndingPattern = "\xc0\x03\x5f\xd6";
break;
case Triple::mips:
case Triple::mipsel:
InstructionAlignment = 4;
SyscallHelper = "helper_raise_exception";
SyscallNumberRegister = "v0";
StackPointerRegister = "sp";
ReturnAddressRegister = "ra";
NoReturnSyscalls = {
0x1096, // exit_group
0xfa1, // exit
0xfab // execve
};
DelaySlotSize = 1;
ABIRegisters = { { v0_mips }, { v1_mips }, { a0_mips }, { a1_mips },
{ a2_mips }, { a3_mips }, { s0_mips }, { s1_mips },
{ s2_mips }, { s3_mips }, { s4_mips }, { s5_mips },
{ s6_mips }, { s7_mips }, { gp_mips }, { sp_mips },
{ fp_mips }, { ra_mips } };
HasRelocationAddend = false;
// R_MIPS_RELATIVE does not exist since the GOT has implicit base-relative
// relocations
RelocationTypes[R_MIPS_IMPLICIT_RELATIVE] = RD(RD::BaseRelative,
RD::TargetValue);
RelocationTypes[R_MIPS_JUMP_SLOT] = RD(RD::SymbolRelative);
RelocationTypes[R_MIPS_GLOB_DAT] = RD(RD::SymbolRelative);
RelocationTypes[R_MIPS_COPY] = RD(RD::LabelOnly, RD::TargetValue);
// jr ra
BasicBlockEndingPattern = ((Arch == Triple::mips) ? "\x08\x00\xe0\x03" :
"\x03\xe0\x00\x08");
break;
case Triple::systemz:
SyscallHelper = "helper_exception";
SyscallNumberRegister = "r1";
StackPointerRegister = "r15";
ReturnAddressRegister = "r14";
InstructionAlignment = 2;
NoReturnSyscalls = {
0xf8, // exit_group
0x1, // exit
0xb, // execve
};
HasRelocationAddend = true;
// TODO: investigate (R_390_RELATIVE does not exist)
RelocationTypes[R_390_GLOB_DAT] = RD(RD::SymbolRelative);
RelocationTypes[R_390_COPY] = RD(RD::LabelOnly, RD::TargetValue);
ABIRegisters = {
{ r0_systemz }, { r1_systemz }, { r2_systemz }, { r3_systemz },
{ r4_systemz }, { r5_systemz }, { r6_systemz }, { r7_systemz },
{ r8_systemz }, { r9_systemz }, { r10_systemz }, { r11_systemz },
{ r12_systemz }, { r13_systemz }, { r14_systemz }, { r15_systemz },
{ f0_systemz }, { f1_systemz }, { f2_systemz }, { f3_systemz },
{ f4_systemz }, { f5_systemz }, { f6_systemz }, { f7_systemz },
{ f8_systemz }, { f9_systemz }, { f10_systemz }, { f11_systemz },
{ f12_systemz }, { f13_systemz }, { f14_systemz }, { f15_systemz }
};
break;
default:
revng_abort();
}
TheArchitecture = Architecture(TheBinary->getArch(),
InstructionAlignment,
1,
TheBinary->isLittleEndian(),
TheBinary->getBytesInAddress() * 8,
SyscallHelper,
SyscallNumberRegister,
NoReturnSyscalls,
DelaySlotSize,
StackPointerRegister,
ReturnAddressRegister,
MinimalFinalStackOffset,
ABIRegisters,
PCMContextIndex,
WriteRegisterAsm,
ReadRegisterAsm,
JumpAsm,
HasRelocationAddend,
std::move(RelocationTypes),
BasicBlockEndingPattern,
DefaultABI);
if (TheBinary->isELF()) {
if (TheArchitecture.pointerSize() == 32) {
if (TheArchitecture.isLittleEndian()) {
if (TheArchitecture.hasRelocationAddend()) {
parseELF<object::ELF32LE, true>(TheBinary, PreferedBaseAddress);
} else {
parseELF<object::ELF32LE, false>(TheBinary, PreferedBaseAddress);
}
} else {
if (TheArchitecture.hasRelocationAddend()) {
parseELF<object::ELF32BE, true>(TheBinary, PreferedBaseAddress);
} else {
parseELF<object::ELF32BE, false>(TheBinary, PreferedBaseAddress);
}
}
} else if (TheArchitecture.pointerSize() == 64) {
if (TheArchitecture.isLittleEndian()) {
if (TheArchitecture.hasRelocationAddend()) {
parseELF<object::ELF64LE, true>(TheBinary, PreferedBaseAddress);
} else {
parseELF<object::ELF64LE, false>(TheBinary, PreferedBaseAddress);
}
} else {
if (TheArchitecture.hasRelocationAddend()) {
parseELF<object::ELF64BE, true>(TheBinary, PreferedBaseAddress);
} else {
parseELF<object::ELF64BE, false>(TheBinary, PreferedBaseAddress);
}
}
} else {
revng_assert("Unexpect address size");
}
} else if (TheBinary->isCOFF()) {
revng_assert(TheArchitecture.pointerSize() == 32
|| TheArchitecture.pointerSize() == 64,
"Only 32/64-bit COFF files are supported");
revng_assert(TheArchitecture.isLittleEndian() == true,
"Only Little-Endian COFF files are supported");
// TODO handle relocations
parseCOFF(TheBinary, PreferedBaseAddress);
} else if (auto *MachO = dyn_cast<object::MachOObjectFile>(TheBinary)) {
using namespace llvm::MachO;
using namespace llvm::object;
using LoadCommandInfo = MachOObjectFile::LoadCommandInfo;
Triple::ArchType Arch = TheBinary->getArch();
StringRef StringDataRef = TheBinary->getData();
auto RawDataRef = ArrayRef<uint8_t>(StringDataRef.bytes_begin(),
StringDataRef.size());
bool MustSwap = TheArchitecture.isLittleEndian() != sys::IsLittleEndianHost;
bool EntryPointFound = false;
Optional<uint64_t> EntryPointOffset;
for (const LoadCommandInfo &LCI : MachO->load_commands()) {
switch (LCI.C.cmd) {
case LC_SEGMENT:
parseMachOSegment(RawDataRef, MachO->getSegmentLoadCommand(LCI));
break;
case LC_SEGMENT_64:
parseMachOSegment(RawDataRef, MachO->getSegment64LoadCommand(LCI));
break;
case LC_UNIXTHREAD: {
revng_check(not EntryPointFound);
EntryPointFound = true;
const uint8_t *Pointer = reinterpret_cast<const uint8_t *>(LCI.Ptr);
ArrayRef<uint8_t> CommandBuffer(Pointer + sizeof(thread_command),
LCI.C.cmdsize - sizeof(thread_command));
revng_check(contains(RawDataRef, CommandBuffer));
EntryPoint = getInitialPC(Arch, MustSwap, CommandBuffer);
} break;
case LC_MAIN:
revng_check(not EntryPointFound);
EntryPointFound = true;
// This is an offset, delay translation to code for later
EntryPointOffset = MachO->getEntryPointCommand(LCI).entryoff;
break;
case LC_FUNCTION_STARTS:
case LC_DATA_IN_CODE:
case LC_SYMTAB:
case LC_DYSYMTAB:
// TODO: very interesting
break;
}
}
if (EntryPointOffset)
EntryPoint = virtualAddressFromOffset(*EntryPointOffset).toPC(Arch);
const uint64_t PointerSize = TheArchitecture.pointerSize() / 8;
Error TheError = Error::success();
for (const MachOBindEntry &U : MachO->bindTable(TheError))
registerBindEntry(&U, PointerSize);
revng_check(not TheError);
for (const MachOBindEntry &U : MachO->lazyBindTable(TheError))
registerBindEntry(&U, PointerSize);
revng_check(not TheError);
// TODO: we should handle weak symbols
for (const MachOBindEntry &U : MachO->weakBindTable(TheError))
registerBindEntry(&U, PointerSize);
revng_check(not TheError);
} else {
revng_assert("Unsupported file format.");
}
rebuildLabelsMap();
}
void BinaryFile::registerBindEntry(const object::MachOBindEntry *Entry,
uint64_t PointerSize) {
using namespace llvm::MachO;
using namespace llvm::object;
const auto Origin = LabelOrigin::DynamicRelocation;
MetaAddress Target = MetaAddress::invalid();
uint64_t Addend = static_cast<uint64_t>(Entry->addend());
uint64_t Size = 0;
switch (Entry->type()) {
case BIND_TYPE_INVALID:
case BIND_TYPE_POINTER:
Target = fromGeneric(Entry->address());
Size = PointerSize;
break;
case BIND_TYPE_TEXT_ABSOLUTE32:
Target = fromPC(Entry->address());
Size = 32 / 8;
break;
case BIND_TYPE_TEXT_PCREL32:
Target = fromPC(Entry->address());
Size = 32 / 8;
Addend -= Target.address();
break;
default:
revng_abort();
}
registerLabel(Label::createSymbolRelativeValue(Origin,
Target,
Size,
Entry->symbolName(),
SymbolType::Unknown,
Addend));
}
class FilePortion {
private:
bool HasAddress;
bool HasSize;
uint64_t Size;
MetaAddress Address;
public:
FilePortion() :
HasAddress(false),
HasSize(false),
Size(0),
Address(MetaAddress::invalid()) {}
public:
void setAddress(MetaAddress Address) {
HasAddress = true;
this->Address = Address;
}
void setSize(uint64_t Size) {
HasSize = true;
this->Size = Size;
}
MetaAddress addressAtOffset(uint64_t Offset) {
revng_assert(HasAddress and HasSize);
revng_assert(Offset <= Size);
return Address + Offset;
}
template<typename T>
MetaAddress addressAtIndex(uint64_t Index) {
revng_assert(HasAddress and HasSize);
uint64_t Offset = Index * sizeof(T);
revng_assert(Offset <= Size);
return Address + Offset;
}
bool isAvailable() const { return HasAddress; }
bool isExact() const {
revng_assert(HasAddress);
return HasSize;
}
StringRef extractString(const std::vector<SegmentInfo> &Segments) const {
ArrayRef<uint8_t> Data = extractData(Segments);
const char *AsChar = reinterpret_cast<const char *>(Data.data());
return StringRef(AsChar, Data.size());
}
template<typename T>
ArrayRef<T> extractAs(const std::vector<SegmentInfo> &Segments) const {
ArrayRef<uint8_t> Data = extractData(Segments);
const size_t TypeSize = sizeof(T);
revng_assert(Data.size() % TypeSize == 0);
return ArrayRef<T>(reinterpret_cast<const T *>(Data.data()),
Data.size() / TypeSize);
}
ArrayRef<uint8_t>
extractData(const std::vector<SegmentInfo> &Segments) const {
revng_assert(HasAddress);
for (const SegmentInfo &Segment : Segments) {
if (Segment.contains(Address)) {
uint64_t Offset = Address - Segment.StartVirtualAddress;
uint64_t AvailableSize = Segment.size() - Offset;
uint64_t TheSize = AvailableSize;
if (HasSize) {
revng_assert(AvailableSize >= Size);
TheSize = Size;
}
return { ArrayRef<uint8_t>(Segment.Data.data() + Offset, TheSize) };
}
}
revng_abort();
}
};
template<typename T, bool HasAddend>
struct RelocationHelper {
static uint64_t getAddend(llvm::object::Elf_Rel_Impl<T, HasAddend>);
};
template<typename T>
struct RelocationHelper<T, true> {
static uint64_t getAddend(llvm::object::Elf_Rel_Impl<T, true> Relocation) {
return Relocation.r_addend;
}
};
template<typename T>
struct RelocationHelper<T, false> {
static uint64_t getAddend(llvm::object::Elf_Rel_Impl<T, false>) { return 0; }
};
static bool shouldIgnoreSymbol(StringRef Name) {
return Name == "$a" or Name == "$d";
}
static uint64_t u64(uint64_t Value) {
return Value;
}
void BinaryFile::parseCOFF(object::ObjectFile *TheBinary, uint64_t) {
using object::COFFObjectFile;
auto TheCOFFOrErr = COFFObjectFile::create(TheBinary->getMemoryBufferRef());
if (not TheCOFFOrErr) {
logAllUnhandledErrors(TheCOFFOrErr.takeError(), errs(), "");
revng_abort();
}
COFFObjectFile &TheCOFF = *TheCOFFOrErr.get();
const object::pe32_header *PE32Header = TheCOFF.getPE32Header();
MetaAddress ImageBase = MetaAddress::invalid();
if (PE32Header) {
// TODO: ImageBase should aligned to 4kb pages, should we check that?
ImageBase = fromPC(PE32Header->ImageBase);
EntryPoint = ImageBase + u64(PE32Header->AddressOfEntryPoint);
ProgramHeaders.Count = PE32Header->NumberOfRvaAndSize;
ProgramHeaders.Size = PE32Header->SizeOfHeaders;
} else {
const object::pe32plus_header *PE32PlusHeader = TheCOFF.getPE32PlusHeader();
if (!PE32PlusHeader) {
revng_assert("Invalid PE Header.\n");
return;
}
// PE32+ Header
ImageBase = fromPC(PE32PlusHeader->ImageBase);
EntryPoint = ImageBase + u64(PE32PlusHeader->AddressOfEntryPoint);
ProgramHeaders.Count = PE32PlusHeader->NumberOfRvaAndSize;
ProgramHeaders.Size = PE32PlusHeader->SizeOfHeaders;
}
// Read sections
for (const llvm::object::SectionRef &SecRef : TheCOFF.sections()) {
unsigned Id = TheCOFF.getSectionID(SecRef);
Expected<const object::coff_section *> SecOrErr = TheCOFF.getSection(Id);
if (not SecOrErr) {
logAllUnhandledErrors(SecOrErr.takeError(), errs(), "");
revng_abort();
}
const object::coff_section *CoffRef = *SecOrErr;
// VirtualSize might be larger than SizeOfRawData (extra data at the end of
// the section) or viceversa (data mapped in memory but not present in
// memory, e.g., .bss)
uint64_t SegmentSize = std::min(CoffRef->VirtualSize,
CoffRef->SizeOfRawData);
using namespace nooverflow;
SegmentInfo Segment;
Segment.StartVirtualAddress = ImageBase + u64(CoffRef->VirtualAddress);
Segment.EndVirtualAddress = Segment.StartVirtualAddress
+ u64(CoffRef->VirtualSize);
Segment.StartFileOffset = CoffRef->PointerToRawData;
Segment.EndFileOffset = Segment.StartFileOffset + SegmentSize;
Segment.IsExecutable = CoffRef->Characteristics
& COFF::IMAGE_SCN_MEM_EXECUTE;
Segment.IsReadable = CoffRef->Characteristics & COFF::IMAGE_SCN_MEM_READ;
Segment.IsWriteable = CoffRef->Characteristics & COFF::IMAGE_SCN_MEM_WRITE;
StringRef StringDataRef = SecRef.getObject()->getData();
auto RawDataRef = ArrayRef<uint8_t>(StringDataRef.bytes_begin(),
StringDataRef.size());
Segment.Data = ArrayRef<uint8_t>(*add(RawDataRef.begin(),
CoffRef->PointerToRawData),
SegmentSize);
revng_assert(contains(RawDataRef, Segment.Data));
Segments.push_back(Segment);
}
}
template<typename T>
void BinaryFile::parseMachOSegment(ArrayRef<uint8_t> RawDataRef,
const T &SegmentCommand) {
using namespace llvm::MachO;
using namespace llvm::object;
using namespace nooverflow;
SegmentInfo Segment;
Segment.StartVirtualAddress = fromGeneric(SegmentCommand.vmaddr);
Segment.EndVirtualAddress = fromGeneric(SegmentCommand.vmaddr)
+ SegmentCommand.vmsize;
Segment.StartFileOffset = SegmentCommand.fileoff;
Segment.EndFileOffset = *add(SegmentCommand.fileoff, SegmentCommand.filesize);
Segment.IsExecutable = SegmentCommand.initprot & VM_PROT_EXECUTE;
Segment.IsReadable = SegmentCommand.initprot & VM_PROT_READ;
Segment.IsWriteable = SegmentCommand.initprot & VM_PROT_WRITE;
Segment.Data = ArrayRef<uint8_t>(*add(RawDataRef.begin(),
SegmentCommand.fileoff),
SegmentCommand.filesize);
revng_assert(contains(RawDataRef, Segment.Data));
Segments.push_back(Segment);
}
template<typename T, bool HasAddend>
void BinaryFile::parseELF(object::ObjectFile *TheBinary,
uint64_t PreferedBaseAddress) {
// Parse the ELF file
auto TheELFOrErr = object::ELFFile<T>::create(TheBinary->getData());
if (not TheELFOrErr) {
logAllUnhandledErrors(TheELFOrErr.takeError(), errs(), "");
revng_abort();
}
object::ELFFile<T> &TheELF = *TheELFOrErr;
// BaseAddress makes sense only for shared (relocatable, PIC) objects
auto Type = TheELF.getHeader().e_type;
if (Type == ELF::ET_DYN) {
BaseAddress = PreferedBaseAddress;
}
revng_assert(Type == ELF::ET_DYN or Type == ELF::ET_EXEC,
"rev.ng currently handles executables and "
"dynamic libraries only.");
// Look for static or dynamic symbols and relocations
using ConstElf_ShdrPtr = const typename object::ELFFile<T>::Elf_Shdr *;
using Elf_PhdrPtr = const typename object::ELFFile<T>::Elf_Phdr *;
ConstElf_ShdrPtr SymtabShdr = nullptr;
Elf_PhdrPtr DynamicPhdr = nullptr;
Optional<MetaAddress> DynamicAddress;
Optional<MetaAddress> EHFrameAddress;
Optional<uint64_t> EHFrameSize;
Optional<MetaAddress> EHFrameHdrAddress;
auto Sections = TheELF.sections();
if (not Sections) {
logAllUnhandledErrors(std::move(Sections.takeError()), errs(), "");
} else {
for (auto &Section : *Sections) {
auto NameOrErr = TheELF.getSectionName(Section);
if (NameOrErr) {
auto &Name = *NameOrErr;
if (Name == ".symtab") {
// TODO: check dedicated field in section header
revng_assert(SymtabShdr == nullptr, "Duplicate .symtab");
SymtabShdr = &Section;
} else if (Name == ".eh_frame") {
revng_assert(not EHFrameAddress, "Duplicate .eh_frame");
EHFrameAddress = relocate(fromGeneric(Section.sh_addr));
EHFrameSize = static_cast<uint64_t>(Section.sh_size);
} else if (Name == ".dynamic") {
revng_assert(not DynamicAddress, "Duplicate .dynamic");
DynamicAddress = relocate(fromGeneric(Section.sh_addr));
}
}
}
}
// If we found a symbol table
if (SymtabShdr != nullptr && SymtabShdr->sh_link != 0) {
// Obtain a reference to the string table
auto Strtab = TheELF.getSection(SymtabShdr->sh_link);
if (not Strtab) {
logAllUnhandledErrors(std::move(Strtab.takeError()), errs(), "");
revng_abort();
}
auto StrtabArray = TheELF.getSectionContents(**Strtab);
if (not StrtabArray) {
logAllUnhandledErrors(std::move(StrtabArray.takeError()), errs(), "");
revng_abort();
}
StringRef StrtabContent(reinterpret_cast<const char *>(StrtabArray->data()),
StrtabArray->size());
// Collect symbol names
auto ELFSymbols = TheELF.symbols(SymtabShdr);
if (not ELFSymbols) {
logAllUnhandledErrors(std::move(ELFSymbols.takeError()), errs(), "");
revng_abort();
}
for (auto &Symbol : *ELFSymbols) {
auto Name = Symbol.getName(StrtabContent);
if (not Name) {
logAllUnhandledErrors(std::move(Name.takeError()), errs(), "");
revng_abort();
}
auto SymbolType = SymbolType::fromELF(Symbol.getType());
if (shouldIgnoreSymbol(*Name) or Symbol.st_shndx == ELF::SHN_UNDEF)
continue;
MetaAddress Address = MetaAddress::invalid();
if (SymbolType == SymbolType::Code)
Address = relocate(fromPC(Symbol.st_value));
else
Address = relocate(fromGeneric(Symbol.st_value));
registerLabel(Label::createSymbol(LabelOrigin::StaticSymbol,
Address,
Symbol.st_size,
*Name,
SymbolType));
}
}
const auto &ElfHeader = TheELF.getHeader();
EntryPoint = relocate(fromPC(ElfHeader.e_entry));
ProgramHeaders.Count = ElfHeader.e_phnum;
ProgramHeaders.Size = ElfHeader.e_phentsize;
// Loop over the program headers looking for PT_LOAD segments, read them out
// and create a global variable for each one of them (writable or read-only),
// assign them a section and output information about them in the linking info
// CSV
using Elf_Phdr = const typename object::ELFFile<T>::Elf_Phdr;
using Elf_Dyn = const typename object::ELFFile<T>::Elf_Dyn;
using Elf_Addr = const typename object::ELFFile<T>::Elf_Addr;
auto ProgHeaders = TheELF.program_headers();
if (not ProgHeaders) {
logAllUnhandledErrors(std::move(ProgHeaders.takeError()), errs(), "");
revng_abort();
}
auto RawDataRef = ArrayRef<uint8_t>(TheELF.base(), TheELF.getBufSize());
for (Elf_Phdr &ProgramHeader : *ProgHeaders) {
switch (ProgramHeader.p_type) {
case ELF::PT_LOAD: {
using namespace nooverflow;
SegmentInfo Segment;
auto Start = relocate(fromGeneric(ProgramHeader.p_vaddr));
Segment.StartVirtualAddress = Start;
Segment.EndVirtualAddress = Start + u64(ProgramHeader.p_memsz);
Segment.StartFileOffset = ProgramHeader.p_offset;
Segment.EndFileOffset = *add(ProgramHeader.p_offset,
ProgramHeader.p_filesz);
Segment.IsReadable = ProgramHeader.p_flags & ELF::PF_R;
Segment.IsWriteable = ProgramHeader.p_flags & ELF::PF_W;
Segment.IsExecutable = ProgramHeader.p_flags & ELF::PF_X;
Segment.Data = ArrayRef<uint8_t>(*add(RawDataRef.begin(),
ProgramHeader.p_offset),
ProgramHeader.p_filesz);
revng_assert(contains(RawDataRef, Segment.Data));
// If it's an executable segment, and we've been asked so, register
// which sections actually contain code
if (Sections and not IgnoreDebugSymbols and Segment.IsExecutable) {
using Elf_Shdr = const typename object::ELFFile<T>::Elf_Shdr;
auto Inserter = std::back_inserter(Segment.ExecutableSections);
for (Elf_Shdr &SectionHeader : *Sections) {
if (SectionHeader.sh_flags & ELF::SHF_EXECINSTR) {
auto SectionStart = relocate(fromGeneric(SectionHeader.sh_addr));
auto SectionEnd = SectionStart + u64(SectionHeader.sh_size);
Inserter = make_pair(SectionStart, SectionEnd);
}
}
}
Segments.push_back(Segment);
// Check if it's the segment containing the program headers
auto ProgramHeaderStart = ProgramHeader.p_offset;
auto ProgramHeaderEnd = ProgramHeader.p_offset
+ u64(ProgramHeader.p_filesz);
if (ProgramHeaderStart <= ElfHeader.e_phoff
&& ElfHeader.e_phoff < ProgramHeaderEnd) {
MetaAddress PhdrAddress = (relocate(fromGeneric(ProgramHeader.p_vaddr))
+ u64(ElfHeader.e_phoff)
- u64(ProgramHeader.p_offset));
ProgramHeaders.Address = PhdrAddress;
}
} break;
case ELF::PT_GNU_EH_FRAME:
revng_assert(!EHFrameHdrAddress);
EHFrameHdrAddress = relocate(fromGeneric(ProgramHeader.p_vaddr));
break;
case ELF::PT_DYNAMIC:
revng_assert(DynamicPhdr == nullptr, "Duplicate .dynamic program header");
DynamicPhdr = &ProgramHeader;
MetaAddress DynamicPhdrMA = relocate(fromGeneric(DynamicPhdr->p_vaddr));
revng_assert(not DynamicAddress or DynamicPhdrMA == *DynamicAddress,
".dynamic and PT_DYNAMIC have different addresses");
DynamicAddress = relocate(DynamicPhdrMA);
break;
}
}
revng_assert((DynamicPhdr != nullptr) == (DynamicAddress.hasValue()));
Optional<uint64_t> FDEsCount;
if (EHFrameHdrAddress) {
MetaAddress Address = MetaAddress::invalid();
std::tie(Address, FDEsCount) = ehFrameFromEhFrameHdr<T>(*EHFrameHdrAddress);
if (EHFrameAddress) {
revng_assert(*EHFrameAddress == Address);
}
EHFrameAddress = Address;
}
if (EHFrameAddress)
parseEHFrame<T>(*EHFrameAddress, FDEsCount, EHFrameSize);
// Parse the .dynamic table
if (DynamicPhdr != nullptr) {
SmallVector<uint64_t, 10> NeededLibraryNameOffsets;
FilePortion DynstrPortion;
FilePortion DynsymPortion;
FilePortion ReldynPortion;
FilePortion RelpltPortion;
FilePortion GotPortion;
Optional<uint64_t> SymbolsCount;
Optional<uint64_t> MIPSFirstGotSymbol;
Optional<uint64_t> MIPSLocalGotEntries;
bool IsMIPS = (TheArchitecture.type() == Triple::mips
or TheArchitecture.type() == Triple::mipsel);
auto DynamicEntries = TheELF.dynamicEntries();
if (not DynamicEntries) {
logAllUnhandledErrors(std::move(DynamicEntries.takeError()), errs(), "");
revng_abort();
}
for (Elf_Dyn &DynamicTag : *DynamicEntries) {
auto TheTag = DynamicTag.getTag();
MetaAddress Relocated = relocate(fromGeneric(DynamicTag.getPtr()));
switch (TheTag) {
case ELF::DT_NEEDED:
NeededLibraryNameOffsets.push_back(DynamicTag.getVal());
break;
case ELF::DT_STRTAB:
DynstrPortion.setAddress(Relocated);
break;
case ELF::DT_STRSZ:
DynstrPortion.setSize(DynamicTag.getVal());
break;
case ELF::DT_SYMTAB:
DynsymPortion.setAddress(Relocated);
break;
case ELF::DT_JMPREL:
RelpltPortion.setAddress(Relocated);
break;
case ELF::DT_PLTRELSZ:
RelpltPortion.setSize(DynamicTag.getVal());
break;
case ELF::DT_REL:
case ELF::DT_RELA:
revng_assert(TheTag == (HasAddend ? ELF::DT_RELA : ELF::DT_REL));
ReldynPortion.setAddress(Relocated);
break;
case ELF::DT_RELSZ:
case ELF::DT_RELASZ:
revng_assert(TheTag == (HasAddend ? ELF::DT_RELASZ : ELF::DT_RELSZ));
ReldynPortion.setSize(DynamicTag.getVal());
break;
case ELF::DT_PLTGOT:
GotPortion.setAddress(Relocated);
// Obtaint the canonical value of the global pointer in MIPS
if (IsMIPS)
CanonicalValues["gp"] = (Relocated + 0x7ff0).address();
break;
case ELF::DT_MIPS_SYMTABNO:
if (IsMIPS)
SymbolsCount = DynamicTag.getVal();
break;
case ELF::DT_MIPS_GOTSYM:
if (IsMIPS)
MIPSFirstGotSymbol = DynamicTag.getVal();
break;
case ELF::DT_MIPS_LOCAL_GOTNO:
if (IsMIPS)
MIPSLocalGotEntries = DynamicTag.getVal();
break;
}
}
if (NeededLibraryNames.size() > 0)
revng_assert(DynstrPortion.isAvailable());
// In MIPS the GOT has one entry per symbol
if (IsMIPS and SymbolsCount and MIPSFirstGotSymbol
and MIPSLocalGotEntries) {
uint32_t GotEntries = (*MIPSLocalGotEntries
+ (*SymbolsCount - *MIPSFirstGotSymbol));
GotPortion.setSize(GotEntries * sizeof(Elf_Addr));
}
StringRef Dynstr;
if (DynstrPortion.isAvailable()) {
Dynstr = DynstrPortion.extractString(Segments);
for (auto Offset : NeededLibraryNameOffsets) {
StringRef LibraryName = Dynstr.slice(Offset, Dynstr.size());
NeededLibraryNames.push_back(LibraryName.data());
}
}
// Collect symbols count and code pointers in image base-relative
// relocations
if (not SymbolsCount) {
SymbolsCount = std::max(symbolsCount<T, HasAddend>(ReldynPortion),
symbolsCount<T, HasAddend>(RelpltPortion));
}
// Collect function addresses contained in dynamic symbols
if (SymbolsCount and *SymbolsCount > 0 and DynsymPortion.isAvailable()) {
using Elf_Sym = llvm::object::Elf_Sym_Impl<T>;
DynsymPortion.setSize(*SymbolsCount * sizeof(Elf_Sym));
ArrayRef<Elf_Sym> Symbols = DynsymPortion.extractAs<Elf_Sym>(Segments);
for (Elf_Sym Symbol : Symbols) {
auto Name = Symbol.getName(Dynstr);
if (not Name) {
logAllUnhandledErrors(std::move(Name.takeError()), errs(), "");
revng_abort();
}
auto SymbolType = SymbolType::fromELF(Symbol.getType());
if (shouldIgnoreSymbol(*Name) or Symbol.st_shndx == ELF::SHN_UNDEF)
continue;
MetaAddress Address = MetaAddress::invalid();
if (SymbolType == SymbolType::Code)
Address = relocate(fromPC(Symbol.st_value));
else
Address = relocate(fromGeneric(Symbol.st_value));
registerLabel(Label::createSymbol(LabelOrigin::DynamicSymbol,
Address,
Symbol.st_size,
*Name,
SymbolType));
}
using Elf_Rel = llvm::object::Elf_Rel_Impl<T, HasAddend>;
if (ReldynPortion.isAvailable()) {
auto Relocations = ReldynPortion.extractAs<Elf_Rel>(Segments);
registerRelocations<T, HasAddend>(Relocations,
DynsymPortion,
DynstrPortion);
}
if (RelpltPortion.isAvailable()) {
auto Relocations = RelpltPortion.extractAs<Elf_Rel>(Segments);
registerRelocations<T, HasAddend>(Relocations,
DynsymPortion,
DynstrPortion);
}
if (IsMIPS and GotPortion.isAvailable()) {
std::vector<Elf_Rel> MIPSImplicitRelocations;
uint32_t GotIndex = 0;
// Perform local relocations on GOT
if (MIPSLocalGotEntries) {
for (; GotIndex < *MIPSLocalGotEntries; GotIndex++) {
auto Address = GotPortion.addressAtIndex<Elf_Addr>(GotIndex);
Elf_Rel NewRelocation;
NewRelocation.r_offset = Address.address();
NewRelocation.setSymbolAndType(0, R_MIPS_IMPLICIT_RELATIVE, false);
MIPSImplicitRelocations.push_back(NewRelocation);
}
}
// Relocate the remaining entries of the GOT with global symbols
if (MIPSFirstGotSymbol and SymbolsCount and DynstrPortion.isAvailable()
and DynsymPortion.isAvailable()) {
for (uint32_t SymbolIndex = *MIPSFirstGotSymbol;
SymbolIndex < *SymbolsCount;
SymbolIndex++, GotIndex++) {
auto Address = GotPortion.addressAtIndex<Elf_Addr>(GotIndex);
Elf_Rel NewRelocation;
NewRelocation.r_offset = Address.address();
NewRelocation.setSymbolAndType(SymbolIndex,
llvm::ELF::R_MIPS_JUMP_SLOT,
false);
MIPSImplicitRelocations.push_back(NewRelocation);
}
}
auto Relocations = ArrayRef<Elf_Rel>(MIPSImplicitRelocations);
registerRelocations<T, HasAddend>(Relocations,
DynsymPortion,
DynstrPortion);
}
}
}
for (Label &L : Labels) {
MetaAddress MA = MetaAddress::invalid();
if (L.isSymbol() and L.isCode())
MA = relocate(L.address());
else if (L.isBaseRelativeValue())
MA = relocate(fromPC(L.value()));
if (MA.isValid())
CodePointers.insert(MA);
}
}
template<typename T, bool HasAddend>
uint64_t BinaryFile::symbolsCount(const FilePortion &Relocations) {
using Elf_Rel = llvm::object::Elf_Rel_Impl<T, HasAddend>;
if (not Relocations.isAvailable())
return 0;
uint32_t SymbolsCount = 0;
revng_assert(Relocations.isExact());
for (Elf_Rel Relocation : Relocations.extractAs<Elf_Rel>(Segments))
SymbolsCount = std::max(SymbolsCount, Relocation.getSymbol(false) + 1);
return SymbolsCount;
}
Optional<uint64_t> BinaryFile::readRawValue(MetaAddress Address,
unsigned Size,
Endianess E) const {
bool IsLittleEndian = ((E == OriginalEndianess) ?
architecture().isLittleEndian() :
E == LittleEndian);
for (auto &Segment : segments()) {
// Note: we also consider writeable memory areas because, despite being
// modifiable, can contain useful information
if (Segment.contains(Address, Size) && Segment.IsReadable) {
uint64_t Offset = Address - Segment.StartVirtualAddress;
// Handle the [p_filesz, p_memsz] portion of the segment
if (Offset > Segment.Data.size())
return 0;
const unsigned char *Start = Segment.Data.data() + Offset;
char Buffer[8] = { 0 };
memcpy(&Buffer,
Start,
std::min(static_cast<size_t>(Size), Segment.Data.size() - Offset));
using support::endianness;
using support::endian::read;
switch (Size) {
case 1:
return read<uint8_t, endianness::little, 1>(&Buffer);
case 2:
if (IsLittleEndian)
return read<uint16_t, endianness::little, 1>(&Buffer);
else
return read<uint16_t, endianness::big, 1>(&Buffer);
case 4:
if (IsLittleEndian)
return read<uint32_t, endianness::little, 1>(&Buffer);
else
return read<uint32_t, endianness::big, 1>(&Buffer);
case 8:
if (IsLittleEndian)
return read<uint64_t, endianness::little, 1>(&Buffer);
else
return read<uint64_t, endianness::big, 1>(&Buffer);
default:
revng_abort("Unexpected read size");
}
}
}
return Optional<uint64_t>();
}
Label BinaryFile::parseRelocation(unsigned char RelocationType,
MetaAddress Target,
uint64_t Addend,
StringRef SymbolName,
uint64_t SymbolSize,
SymbolType::Values SymbolType) {
const auto &RelocationTypes = TheArchitecture.relocationTypes();
auto It = RelocationTypes.find(RelocationType);
if (It == RelocationTypes.end()) {
dbg << "Warning: unhandled relocation type "
<< static_cast<int>(RelocationType) << "\n";
return Label::createInvalid();
}
uint64_t Offset;
using RD = RelocationDescription;
const RD &Description = It->second;
uint64_t PointerSize = TheArchitecture.pointerSize() / 8;
switch (Description.Offset) {
case RD::None:
Offset = 0;
break;
case RD::Addend:
Offset = Addend;
break;
case RD::TargetValue:
Optional<uint64_t> ReadResult = readRawValue(Target, PointerSize);
if (not ReadResult)
return Label::createInvalid();
Offset = *ReadResult;
break;
}
const auto Origin = LabelOrigin::DynamicRelocation;
switch (Description.Type) {
case RD::BaseRelative:
return Label::createBaseRelativeValue(Origin, Target, PointerSize, Offset);
case RD::LabelOnly:
if (shouldIgnoreSymbol(SymbolName))
return Label::createInvalid();
return Label::createSymbol(Origin,
Target,
SymbolSize,
SymbolName,
SymbolType);
case RD::SymbolRelative:
if (shouldIgnoreSymbol(SymbolName))
return Label::createInvalid();
return Label::createSymbolRelativeValue(Origin,
Target,
PointerSize,
SymbolName,
SymbolType,
Offset);
case RD::Invalid:
revng_abort("Invalid relocation type");
break;
}
revng_abort();
}
template<typename T, bool HasAddend>
void BinaryFile::registerRelocations(Elf_Rel_Array<T, HasAddend> Relocations,
const FilePortion &Dynsym,
const FilePortion &Dynstr) {
using Elf_Rel = llvm::object::Elf_Rel_Impl<T, HasAddend>;
using Elf_Sym = llvm::object::Elf_Sym_Impl<T>;
ArrayRef<Elf_Sym> Symbols;
if (Dynsym.isAvailable())
Symbols = Dynsym.extractAs<Elf_Sym>(Segments);
for (Elf_Rel Relocation : Relocations) {
auto Type = static_cast<unsigned char>(Relocation.getType(false));
uint64_t Addend = RelocationHelper<T, HasAddend>::getAddend(Relocation);
MetaAddress Address = relocate(fromGeneric(Relocation.r_offset));
StringRef SymbolName;
uint64_t SymbolSize = 0;
unsigned char SymbolType = llvm::ELF::STT_NOTYPE;
if (Dynsym.isAvailable() and Dynstr.isAvailable()) {
uint32_t SymbolIndex = Relocation.getSymbol(false);
revng_check(SymbolIndex < Symbols.size());
const Elf_Sym &Symbol = Symbols[SymbolIndex];
auto Result = Symbol.getName(Dynstr.extractString(Segments));
if (Result)
SymbolName = *Result;
SymbolSize = Symbol.st_size;
SymbolType = Symbol.getType();
}
registerLabel(parseRelocation(Type,
Address,
Addend,
SymbolName,
SymbolSize,
SymbolType::fromELF(SymbolType)));
}
}
static LabelList &operator+=(LabelList &This, const LabelList &Other) {
This.insert(std::end(This), std::begin(Other), std::end(Other));
return This;
}
void BinaryFile::rebuildLabelsMap() {
using Interval = boost::icl::interval<MetaAddress, compareAddress>;
// Clear the map
LabelsMap.clear();
// Identify all the 0-sized labels
std::vector<Label *> ZeroSizedLabels;
for (Label &L : Labels)
if (L.isSymbol() and L.size() == 0)
ZeroSizedLabels.push_back(&L);
// Sort the 0-sized labels
auto Compare = [](Label *This, Label *Other) {
return This->address().addressLowerThan(Other->address());
};
std::sort(ZeroSizedLabels.begin(), ZeroSizedLabels.end(), Compare);
// Create virtual terminator label
revng_assert(Segments.size() > 0);
MetaAddress HighestAddress = Segments[0].EndVirtualAddress;
for (const SegmentInfo &Segment : skip(1, Segments))
if (Segment.EndVirtualAddress.addressGreaterThan(HighestAddress))
HighestAddress = Segment.EndVirtualAddress;
Label EndLabel = Label::createSymbol(LabelOrigin::Unknown,
HighestAddress,
0,
"",
SymbolType::Unknown);
ZeroSizedLabels.push_back(&EndLabel);
// Insert the 0-sized labels in the map
for (unsigned I = 0; I < ZeroSizedLabels.size() - 1; I++) {
MetaAddress Start = ZeroSizedLabels[I]->address();
const SegmentInfo *Segment = findSegment(Start);
if (Segment == nullptr)
continue;
// Limit the symbol to the end of the segment containing it
MetaAddress End;
MetaAddress NextAddress = ZeroSizedLabels[I + 1]->address();
MetaAddress LastAddress = Segment->EndVirtualAddress;
if (NextAddress.addressLowerThan(LastAddress)) {
End = NextAddress;
} else {
End = LastAddress;
}
revng_assert(Start.addressLowerThanOrEqual(End));
// Register virtual size
ZeroSizedLabels[I]->setVirtualSize(End - Start);
}
// Insert all the other labels in the map
for (Label &L : Labels) {
MetaAddress Start = L.address();
MetaAddress End = L.address() + L.size();
LabelsMap += make_pair(Interval::right_open(Start, End), LabelList{ &L });
}
// Dump the map out
if (LabelsLog.isEnabled()) {
for (auto &P : LabelsMap) {
dbg << "[";
P.first.lower().dump(dbg);
dbg << ",";
P.first.upper().dump(dbg);
dbg << "]\n";
for (const Label *L : P.second) {
dbg << " ";
L->dump(dbg);
dbg << "\n";
}
dbg << "\n";
}
}
}
//
// .eh_frame-related functions
//
template<typename E>
class DwarfReader {
public:
DwarfReader(Triple::ArchType Architecture,
ArrayRef<uint8_t> Buffer,
MetaAddress Address) :
Architecture(Architecture),
Address(Address),
Start(Buffer.data()),
Cursor(Buffer.data()),
End(Buffer.data() + Buffer.size()) {}
uint8_t readNextU8() { return readNext<uint8_t>(); }
uint16_t readNextU16() { return readNext<uint16_t>(); }
uint32_t readNextU32() { return readNext<uint32_t>(); }
uint64_t readNextU64() { return readNext<uint64_t>(); }
uint64_t readNextU() {
if (is64())
return readNextU64();
else
return readNextU32();
}
uint64_t readULEB128() {
unsigned Length;
uint64_t Result = decodeULEB128(Cursor, &Length);
Cursor += Length;
revng_assert(Cursor <= End);
return Result;
}
int64_t readSLEB128() {
unsigned Length;
int64_t Result = decodeSLEB128(Cursor, &Length);
Cursor += Length;
revng_assert(Cursor <= End);
return Result;
}
int64_t readSignedValue(unsigned Encoding) {
return static_cast<int64_t>(readValue(Encoding));
}
uint64_t readUnsignedValue(unsigned Encoding) {
return static_cast<uint64_t>(readValue(Encoding));
}
Pointer
readPointer(unsigned Encoding, MetaAddress Base = MetaAddress::invalid()) {
revng_assert((Encoding & ~(0x70 | 0x0F | dwarf::DW_EH_PE_indirect)) == 0);
// Handle PC-relative values
revng_assert(Cursor >= Start);
if ((Encoding & 0x70) == dwarf::DW_EH_PE_pcrel) {
revng_assert(Base.isInvalid());
Base = Address + (Cursor - Start);
}
if (isSigned(Encoding & 0x0F)) {
return readPointerInternal(readSignedValue(Encoding), Encoding, Base);
} else {
return readPointerInternal(readUnsignedValue(Encoding), Encoding, Base);
}
}
void moveTo(uint64_t Offset) {
const uint8_t *NewCursor = Start + Offset;
revng_assert(NewCursor >= Cursor && NewCursor <= End);
Cursor = NewCursor;
}
bool eof() const { return Cursor >= End; }
uint64_t offset() const { return Cursor - Start; }
private:
template<typename T>
std::conditional_t<std::numeric_limits<T>::is_signed, int64_t, uint64_t>
readNext() {
constexpr bool IsSigned = std::numeric_limits<T>::is_signed;
using ReturnType = std::conditional_t<IsSigned, int64_t, uint64_t>;
revng_assert(Cursor + sizeof(T) <= End);
auto Result = static_cast<T>(Endianess<T, E>::read(Cursor));
Cursor += sizeof(T);
return static_cast<ReturnType>(Result);
}
static bool isSigned(unsigned Format) {
switch (Format) {
case dwarf::DW_EH_PE_sleb128:
case dwarf::DW_EH_PE_signed:
case dwarf::DW_EH_PE_sdata2:
case dwarf::DW_EH_PE_sdata4:
case dwarf::DW_EH_PE_sdata8:
return true;
case dwarf::DW_EH_PE_absptr:
case dwarf::DW_EH_PE_uleb128:
case dwarf::DW_EH_PE_udata2:
case dwarf::DW_EH_PE_udata4:
case dwarf::DW_EH_PE_udata8:
return false;
default:
revng_abort("Unknown Encoding");
}
}
uint64_t readValue(unsigned Encoding) {
revng_assert((Encoding & ~(0x70 | 0x0F | dwarf::DW_EH_PE_indirect)) == 0);
// Extract the format
unsigned Format = Encoding & 0x0F;
switch (Format) {
case dwarf::DW_EH_PE_uleb128:
return readULEB128();
case dwarf::DW_EH_PE_sleb128:
return readSLEB128();
case dwarf::DW_EH_PE_absptr:
if (is64())
return readNext<uint64_t>();
else
return readNext<uint32_t>();
case dwarf::DW_EH_PE_signed:
if (is64())
return readNext<int64_t>();
else
return readNext<int32_t>();
case dwarf::DW_EH_PE_udata2:
return readNext<uint16_t>();
case dwarf::DW_EH_PE_sdata2:
return readNext<int16_t>();
case dwarf::DW_EH_PE_udata4:
return readNext<uint32_t>();
case dwarf::DW_EH_PE_sdata4:
return readNext<int32_t>();
case dwarf::DW_EH_PE_udata8:
return readNext<uint64_t>();
case dwarf::DW_EH_PE_sdata8:
return readNext<int64_t>();
default:
revng_unreachable("Unknown Encoding");
}
}
template<typename T>
Pointer readPointerInternal(T Value, unsigned Encoding, MetaAddress Base) {
bool IsIndirect = Encoding & dwarf::DW_EH_PE_indirect;
if (Base.isInvalid()) {
return Pointer(IsIndirect, MetaAddress::fromGeneric(Architecture, Value));
} else {
unsigned EncodingRelative = Encoding & 0x70;
revng_assert(EncodingRelative == 0 || EncodingRelative == 0x10);
return Pointer(IsIndirect, Base + Value);
}
}
bool is64() const;
private:
Triple::ArchType Architecture;
MetaAddress Address;
const uint8_t *Start;
const uint8_t *Cursor;
const uint8_t *End;
};
template<>
bool DwarfReader<object::ELF32BE>::is64() const {
return false;
}
template<>
bool DwarfReader<object::ELF32LE>::is64() const {
return false;
}
template<>
bool DwarfReader<object::ELF64BE>::is64() const {
return true;
}
template<>
bool DwarfReader<object::ELF64LE>::is64() const {
return true;
}
template<typename T>
std::pair<MetaAddress, uint64_t>
BinaryFile::ehFrameFromEhFrameHdr(MetaAddress EHFrameHdrAddress) {
auto R = getAddressData(EHFrameHdrAddress);
revng_assert(R, ".eh_frame_hdr section not available in any segment");
llvm::ArrayRef<uint8_t> EHFrameHdr = *R;
DwarfReader<T> EHFrameHdrReader(TheArchitecture.type(),
EHFrameHdr,
EHFrameHdrAddress);
uint64_t VersionNumber = EHFrameHdrReader.readNextU8();
revng_assert(VersionNumber == 1);
// ExceptionFrameEncoding
uint64_t ExceptionFrameEncoding = EHFrameHdrReader.readNextU8();
// FDEsCountEncoding
unsigned FDEsCountEncoding = EHFrameHdrReader.readNextU8();
// LookupTableEncoding
EHFrameHdrReader.readNextU8();
Pointer EHFramePointer = EHFrameHdrReader.readPointer(ExceptionFrameEncoding);
uint64_t FDEsCount = EHFrameHdrReader.readUnsignedValue(FDEsCountEncoding);
return { getGenericPointer<T>(EHFramePointer), FDEsCount };
}
template<typename T>
void BinaryFile::parseEHFrame(MetaAddress EHFrameAddress,
Optional<uint64_t> FDEsCount,
Optional<uint64_t> EHFrameSize) {
revng_assert(FDEsCount || EHFrameSize);
auto R = getAddressData(EHFrameAddress);
// Sometimes the .eh_frame section is present but not mapped in memory. This
// means it cannot be used at runtime, therefore we can ignore it.
if (!R)
return;
llvm::ArrayRef<uint8_t> EHFrame = *R;
DwarfReader<T> EHFrameReader(TheArchitecture.type(), EHFrame, EHFrameAddress);
// A few fields of the CIE are used when decoding the FDE's. This struct
// will cache those fields we need so that we don't have to decode it
// repeatedly for each FDE that references it.
struct DecodedCIE {
Optional<uint32_t> FDEPointerEncoding;
Optional<uint32_t> LSDAPointerEncoding;
bool hasAugmentationLength;
};
// Map from the start offset of the CIE to the cached data for that CIE.
DenseMap<uint64_t, DecodedCIE> CachedCIEs;
unsigned FDEIndex = 0;
while (!EHFrameReader.eof()
&& ((FDEsCount && FDEIndex < *FDEsCount)
|| (EHFrameSize && EHFrameReader.offset() < *EHFrameSize))) {
uint64_t StartOffset = EHFrameReader.offset();
// Read the length of the entry
uint64_t Length = EHFrameReader.readNextU32();
if (Length == 0xffffffff)
Length = EHFrameReader.readNextU64();
// Compute the end offset of the entry
uint64_t OffsetAfterLength = EHFrameReader.offset();
uint64_t EndOffset = OffsetAfterLength + Length;
// Zero-sized entry, skip it
if (Length == 0) {
revng_assert(EHFrameReader.offset() == EndOffset);
continue;
}
// Get the entry ID, 0 means it's a CIE, otherwise it's a FDE
uint32_t ID = EHFrameReader.readNextU32();
if (ID == 0) {
// This is a CIE
revng_log(EhFrameLog, "New CIE");
// Ensure the version is the one we expect
uint32_t Version = EHFrameReader.readNextU8();
revng_assert(Version == 1);
// Parse a null terminated augmentation string
SmallString<8> AugmentationString;
for (uint8_t Char = EHFrameReader.readNextU8(); Char != 0;
Char = EHFrameReader.readNextU8())
AugmentationString.push_back(Char);
// Optionally parse the EH data if the augmentation string says it's
// there
if (StringRef(AugmentationString).count("eh") != 0)
EHFrameReader.readNextU();
// CodeAlignmentFactor
EHFrameReader.readULEB128();
// DataAlignmentFactor
EHFrameReader.readULEB128();
// ReturnAddressRegister
EHFrameReader.readNextU8();
Optional<uint64_t> AugmentationLength;
Optional<uint32_t> LSDAPointerEncoding;
Optional<uint32_t> PersonalityEncoding;
Optional<uint32_t> FDEPointerEncoding;
if (!AugmentationString.empty() && AugmentationString.front() == 'z') {
AugmentationLength = EHFrameReader.readULEB128();
// Walk the augmentation string to get all the augmentation data.
for (unsigned I = 1, e = AugmentationString.size(); I != e; ++I) {
char Char = AugmentationString[I];
switch (Char) {
case 'e':
revng_assert((I + 1) != e && AugmentationString[I + 1] == 'h',
"Expected 'eh' in augmentation string");
break;
case 'L':
// This is the only information we really care about, all the rest
// is processed just so we can get here
revng_assert(!LSDAPointerEncoding, "Duplicate LSDA encoding");
LSDAPointerEncoding = EHFrameReader.readNextU8();
break;
case 'P': {
revng_assert(!PersonalityEncoding, "Duplicate personality");
PersonalityEncoding = EHFrameReader.readNextU8();
// Personality
Pointer Personality;
Personality = EHFrameReader.readPointer(*PersonalityEncoding);
auto PersonalityPtr = getCodePointer<T>(Personality);
logAddress(EhFrameLog, "Personality function: ", PersonalityPtr);
// TODO: technically this is not a landing pad
LandingPads.insert(PersonalityPtr);
break;
}
case 'R':
revng_assert(!FDEPointerEncoding, "Duplicate FDE encoding");
FDEPointerEncoding = EHFrameReader.readNextU8();
break;
case 'z':
revng_unreachable("'z' must be first in the augmentation string");
}
}
}
// Cache this entry
CachedCIEs[StartOffset] = { FDEPointerEncoding,
LSDAPointerEncoding,
AugmentationLength.hasValue() };
} else {
// This is an FDE
FDEIndex++;
// The CIE pointer for an FDE is the same location as the ID which we
// already read
uint64_t CIEOffset = OffsetAfterLength - ID;
// Ensure we already met this CIE
auto CIEIt = CachedCIEs.find(CIEOffset);
revng_assert(CIEIt != CachedCIEs.end(),
"Couldn't find CIE at offset in to __eh_frame section");
// Ensure we have at least the pointer encoding
const DecodedCIE &CIE = CIEIt->getSecond();
revng_assert(CIE.FDEPointerEncoding,
"FDE references CIE which did not set pointer encoding");
// PCBegin
auto PCBeginPointer = EHFrameReader.readPointer(*CIE.FDEPointerEncoding);
MetaAddress PCBegin = getGenericPointer<T>(PCBeginPointer);
logAddress(EhFrameLog, "PCBegin: ", PCBegin);
// PCRange
EHFrameReader.readPointer(*CIE.FDEPointerEncoding);
if (CIE.hasAugmentationLength)
EHFrameReader.readULEB128();
// Decode the LSDA if the CIE augmentation string said we should.
if (CIE.LSDAPointerEncoding) {
auto LSDAPointer = EHFrameReader.readPointer(*CIE.LSDAPointerEncoding);
parseLSDA<T>(PCBegin, getGenericPointer<T>(LSDAPointer));
}
}
// Skip all the remaining parts
EHFrameReader.moveTo(EndOffset);
}
}
template<typename T>
void BinaryFile::parseLSDA(MetaAddress FDEStart, MetaAddress LSDAAddress) {
logAddress(EhFrameLog, "LSDAAddress: ", LSDAAddress);
auto R = getAddressData(LSDAAddress);
revng_assert(R, "LSDA not available in any segment");
llvm::ArrayRef<uint8_t> LSDA = *R;
DwarfReader<T> LSDAReader(TheArchitecture.type(), LSDA, LSDAAddress);
uint32_t LandingPadBaseEncoding = LSDAReader.readNextU8();
MetaAddress LandingPadBase = MetaAddress::invalid();
if (LandingPadBaseEncoding != dwarf::DW_EH_PE_omit) {
auto LandingPadBasePointer = LSDAReader.readPointer(LandingPadBaseEncoding);
LandingPadBase = getGenericPointer<T>(LandingPadBasePointer);
} else {
LandingPadBase = FDEStart;
}
logAddress(EhFrameLog, "LandingPadBase: ", LandingPadBase);
uint32_t TypeTableEncoding = LSDAReader.readNextU8();
if (TypeTableEncoding != dwarf::DW_EH_PE_omit)
LSDAReader.readULEB128();
uint32_t CallSiteTableEncoding = LSDAReader.readNextU8();
uint64_t CallSiteTableLength = LSDAReader.readULEB128();
uint64_t CallSiteTableEnd = LSDAReader.offset() + CallSiteTableLength;
while (LSDAReader.offset() < CallSiteTableEnd) {
// InstructionStart
LSDAReader.readPointer(CallSiteTableEncoding);
// InstructionEnd
LSDAReader.readPointer(CallSiteTableEncoding);
// LandingPad
Pointer LandingPadPointer = LSDAReader.readPointer(CallSiteTableEncoding,
LandingPadBase);
MetaAddress LandingPad = getCodePointer<T>(LandingPadPointer);
// Action
LSDAReader.readULEB128();
if (LandingPad.isValid()) {
if (LandingPads.count(LandingPad) == 0)
logAddress(EhFrameLog, "New landing pad found: ", LandingPad);
LandingPads.insert(LandingPad);
}
}
}
static bool isBetterThan(const Label *NewCandidate, const Label *OldCandidate) {
if (OldCandidate == nullptr)
return true;
if (NewCandidate->address().addressGreaterThan(OldCandidate->address()))
return true;
if (NewCandidate->address() == OldCandidate->address()) {
StringRef OldName = OldCandidate->symbolName();
if (OldName.size() == 0)
return true;
}
return false;
}
std::string
BinaryFile::nameForAddress(MetaAddress Address, uint64_t Size) const {
using interval = boost::icl::interval<MetaAddress, compareAddress>;
std::stringstream Result;
const auto &SymbolMap = labelsMap();
auto End = Address.toGeneric() + Size;
revng_assert(Address.isValid() and End.isValid());
auto It = SymbolMap.find(interval::right_open(Address, End));
if (It != SymbolMap.end()) {
// We have to look for (in order):
//
// * Exact match
// * Contained (non 0-sized)
// * Contained (0-sized)
const Label *ExactMatch = nullptr;
const Label *ContainedNonZeroSized = nullptr;
const Label *ContainedZeroSized = nullptr;
for (const Label *L : It->second) {
// Consider symbols only
if (not L->isSymbol())
continue;
if (L->matches(Address, Size)) {
// It's an exact match
ExactMatch = L;
break;
} else if (not L->isSizeVirtual() and L->contains(Address, Size)) {
// It's contained in a not 0-sized symbol
if (isBetterThan(L, ContainedNonZeroSized))
ContainedNonZeroSized = L;
} else if (L->isSizeVirtual() and L->contains(Address, 0)) {
// It's contained in a 0-sized symbol
if (isBetterThan(L, ContainedZeroSized))
ContainedZeroSized = L;
}
}
const Label *Chosen = nullptr;
if (ExactMatch != nullptr)
Chosen = ExactMatch;
else if (ContainedNonZeroSized != nullptr)
Chosen = ContainedNonZeroSized;
else if (ContainedZeroSized != nullptr)
Chosen = ContainedZeroSized;
if (Chosen != nullptr and Chosen->symbolName().size() != 0) {
auto Arch = architecture().type();
Address.dumpRelativeTo(Result,
Chosen->address().toPC(Arch),
Chosen->symbolName());
return Result.str();
}
}
// We don't have a symbol to use, just return the address
Address.dump(Result);
return Result.str();
}
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