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COFFObjectFile.cpp
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//===- COFFObjectFile.cpp - COFF object file implementation ---------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file declares the COFFObjectFile class.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/Triple.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/Object/Binary.h"
#include "llvm/Object/COFF.h"
#include "llvm/Object/Error.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/BinaryStreamReader.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/MemoryBuffer.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <cstring>
#include <limits>
#include <memory>
#include <system_error>
using namespace llvm;
using namespace object;
using support::ulittle16_t;
using support::ulittle32_t;
using support::ulittle64_t;
using support::little16_t;
// Returns false if size is greater than the buffer size. And sets ec.
static bool checkSize(MemoryBufferRef M, std::error_code &EC, uint64_t Size) {
if (M.getBufferSize() < Size) {
EC = object_error::unexpected_eof;
return false;
}
return true;
}
// Sets Obj unless any bytes in [addr, addr + size) fall outsize of m.
// Returns unexpected_eof if error.
template <typename T>
static std::error_code getObject(const T *&Obj, MemoryBufferRef M,
const void *Ptr,
const uint64_t Size = sizeof(T)) {
uintptr_t Addr = uintptr_t(Ptr);
if (std::error_code EC = Binary::checkOffset(M, Addr, Size))
return EC;
Obj = reinterpret_cast<const T *>(Addr);
return std::error_code();
}
// Decode a string table entry in base 64 (//AAAAAA). Expects \arg Str without
// prefixed slashes.
static bool decodeBase64StringEntry(StringRef Str, uint32_t &Result) {
assert(Str.size() <= 6 && "String too long, possible overflow.");
if (Str.size() > 6)
return true;
uint64_t Value = 0;
while (!Str.empty()) {
unsigned CharVal;
if (Str[0] >= 'A' && Str[0] <= 'Z') // 0..25
CharVal = Str[0] - 'A';
else if (Str[0] >= 'a' && Str[0] <= 'z') // 26..51
CharVal = Str[0] - 'a' + 26;
else if (Str[0] >= '0' && Str[0] <= '9') // 52..61
CharVal = Str[0] - '0' + 52;
else if (Str[0] == '+') // 62
CharVal = 62;
else if (Str[0] == '/') // 63
CharVal = 63;
else
return true;
Value = (Value * 64) + CharVal;
Str = Str.substr(1);
}
if (Value > std::numeric_limits<uint32_t>::max())
return true;
Result = static_cast<uint32_t>(Value);
return false;
}
template <typename coff_symbol_type>
const coff_symbol_type *COFFObjectFile::toSymb(DataRefImpl Ref) const {
const coff_symbol_type *Addr =
reinterpret_cast<const coff_symbol_type *>(Ref.p);
assert(!checkOffset(Data, uintptr_t(Addr), sizeof(*Addr)));
#ifndef NDEBUG
// Verify that the symbol points to a valid entry in the symbol table.
uintptr_t Offset = uintptr_t(Addr) - uintptr_t(base());
assert((Offset - getPointerToSymbolTable()) % sizeof(coff_symbol_type) == 0 &&
"Symbol did not point to the beginning of a symbol");
#endif
return Addr;
}
const coff_section *COFFObjectFile::toSec(DataRefImpl Ref) const {
const coff_section *Addr = reinterpret_cast<const coff_section*>(Ref.p);
#ifndef NDEBUG
// Verify that the section points to a valid entry in the section table.
if (Addr < SectionTable || Addr >= (SectionTable + getNumberOfSections()))
report_fatal_error("Section was outside of section table.");
uintptr_t Offset = uintptr_t(Addr) - uintptr_t(SectionTable);
assert(Offset % sizeof(coff_section) == 0 &&
"Section did not point to the beginning of a section");
#endif
return Addr;
}
void COFFObjectFile::moveSymbolNext(DataRefImpl &Ref) const {
auto End = reinterpret_cast<uintptr_t>(StringTable);
if (SymbolTable16) {
const coff_symbol16 *Symb = toSymb<coff_symbol16>(Ref);
Symb += 1 + Symb->NumberOfAuxSymbols;
Ref.p = std::min(reinterpret_cast<uintptr_t>(Symb), End);
} else if (SymbolTable32) {
const coff_symbol32 *Symb = toSymb<coff_symbol32>(Ref);
Symb += 1 + Symb->NumberOfAuxSymbols;
Ref.p = std::min(reinterpret_cast<uintptr_t>(Symb), End);
} else {
llvm_unreachable("no symbol table pointer!");
}
}
Expected<StringRef> COFFObjectFile::getSymbolName(DataRefImpl Ref) const {
return getSymbolName(getCOFFSymbol(Ref));
}
uint64_t COFFObjectFile::getSymbolValueImpl(DataRefImpl Ref) const {
return getCOFFSymbol(Ref).getValue();
}
uint32_t COFFObjectFile::getSymbolAlignment(DataRefImpl Ref) const {
// MSVC/link.exe seems to align symbols to the next-power-of-2
// up to 32 bytes.
COFFSymbolRef Symb = getCOFFSymbol(Ref);
return std::min(uint64_t(32), PowerOf2Ceil(Symb.getValue()));
}
Expected<uint64_t> COFFObjectFile::getSymbolAddress(DataRefImpl Ref) const {
uint64_t Result = cantFail(getSymbolValue(Ref));
COFFSymbolRef Symb = getCOFFSymbol(Ref);
int32_t SectionNumber = Symb.getSectionNumber();
if (Symb.isAnyUndefined() || Symb.isCommon() ||
COFF::isReservedSectionNumber(SectionNumber))
return Result;
Expected<const coff_section *> Section = getSection(SectionNumber);
if (!Section)
return Section.takeError();
Result += (*Section)->VirtualAddress;
// The section VirtualAddress does not include ImageBase, and we want to
// return virtual addresses.
Result += getImageBase();
return Result;
}
Expected<SymbolRef::Type> COFFObjectFile::getSymbolType(DataRefImpl Ref) const {
COFFSymbolRef Symb = getCOFFSymbol(Ref);
int32_t SectionNumber = Symb.getSectionNumber();
if (Symb.getComplexType() == COFF::IMAGE_SYM_DTYPE_FUNCTION)
return SymbolRef::ST_Function;
if (Symb.isAnyUndefined())
return SymbolRef::ST_Unknown;
if (Symb.isCommon())
return SymbolRef::ST_Data;
if (Symb.isFileRecord())
return SymbolRef::ST_File;
// TODO: perhaps we need a new symbol type ST_Section.
if (SectionNumber == COFF::IMAGE_SYM_DEBUG || Symb.isSectionDefinition())
return SymbolRef::ST_Debug;
if (!COFF::isReservedSectionNumber(SectionNumber))
return SymbolRef::ST_Data;
return SymbolRef::ST_Other;
}
Expected<uint32_t> COFFObjectFile::getSymbolFlags(DataRefImpl Ref) const {
COFFSymbolRef Symb = getCOFFSymbol(Ref);
uint32_t Result = SymbolRef::SF_None;
if (Symb.isExternal() || Symb.isWeakExternal())
Result |= SymbolRef::SF_Global;
if (const coff_aux_weak_external *AWE = Symb.getWeakExternal()) {
Result |= SymbolRef::SF_Weak;
if (AWE->Characteristics != COFF::IMAGE_WEAK_EXTERN_SEARCH_ALIAS)
Result |= SymbolRef::SF_Undefined;
}
if (Symb.getSectionNumber() == COFF::IMAGE_SYM_ABSOLUTE)
Result |= SymbolRef::SF_Absolute;
if (Symb.isFileRecord())
Result |= SymbolRef::SF_FormatSpecific;
if (Symb.isSectionDefinition())
Result |= SymbolRef::SF_FormatSpecific;
if (Symb.isCommon())
Result |= SymbolRef::SF_Common;
if (Symb.isUndefined())
Result |= SymbolRef::SF_Undefined;
return Result;
}
uint64_t COFFObjectFile::getCommonSymbolSizeImpl(DataRefImpl Ref) const {
COFFSymbolRef Symb = getCOFFSymbol(Ref);
return Symb.getValue();
}
Expected<section_iterator>
COFFObjectFile::getSymbolSection(DataRefImpl Ref) const {
COFFSymbolRef Symb = getCOFFSymbol(Ref);
if (COFF::isReservedSectionNumber(Symb.getSectionNumber()))
return section_end();
Expected<const coff_section *> Sec = getSection(Symb.getSectionNumber());
if (!Sec)
return Sec.takeError();
DataRefImpl Ret;
Ret.p = reinterpret_cast<uintptr_t>(*Sec);
return section_iterator(SectionRef(Ret, this));
}
unsigned COFFObjectFile::getSymbolSectionID(SymbolRef Sym) const {
COFFSymbolRef Symb = getCOFFSymbol(Sym.getRawDataRefImpl());
return Symb.getSectionNumber();
}
void COFFObjectFile::moveSectionNext(DataRefImpl &Ref) const {
const coff_section *Sec = toSec(Ref);
Sec += 1;
Ref.p = reinterpret_cast<uintptr_t>(Sec);
}
Expected<StringRef> COFFObjectFile::getSectionName(DataRefImpl Ref) const {
const coff_section *Sec = toSec(Ref);
return getSectionName(Sec);
}
uint64_t COFFObjectFile::getSectionAddress(DataRefImpl Ref) const {
const coff_section *Sec = toSec(Ref);
uint64_t Result = Sec->VirtualAddress;
// The section VirtualAddress does not include ImageBase, and we want to
// return virtual addresses.
Result += getImageBase();
return Result;
}
uint64_t COFFObjectFile::getSectionIndex(DataRefImpl Sec) const {
return toSec(Sec) - SectionTable;
}
uint64_t COFFObjectFile::getSectionSize(DataRefImpl Ref) const {
return getSectionSize(toSec(Ref));
}
Expected<ArrayRef<uint8_t>>
COFFObjectFile::getSectionContents(DataRefImpl Ref) const {
const coff_section *Sec = toSec(Ref);
ArrayRef<uint8_t> Res;
if (Error E = getSectionContents(Sec, Res))
return std::move(E);
return Res;
}
uint64_t COFFObjectFile::getSectionAlignment(DataRefImpl Ref) const {
const coff_section *Sec = toSec(Ref);
return Sec->getAlignment();
}
bool COFFObjectFile::isSectionCompressed(DataRefImpl Sec) const {
return false;
}
bool COFFObjectFile::isSectionText(DataRefImpl Ref) const {
const coff_section *Sec = toSec(Ref);
return Sec->Characteristics & COFF::IMAGE_SCN_CNT_CODE;
}
bool COFFObjectFile::isSectionData(DataRefImpl Ref) const {
const coff_section *Sec = toSec(Ref);
return Sec->Characteristics & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA;
}
bool COFFObjectFile::isSectionBSS(DataRefImpl Ref) const {
const coff_section *Sec = toSec(Ref);
const uint32_t BssFlags = COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_MEM_WRITE;
return (Sec->Characteristics & BssFlags) == BssFlags;
}
// The .debug sections are the only debug sections for COFF
// (\see MCObjectFileInfo.cpp).
bool COFFObjectFile::isDebugSection(StringRef SectionName) const {
return SectionName.startswith(".debug");
}
unsigned COFFObjectFile::getSectionID(SectionRef Sec) const {
uintptr_t Offset =
uintptr_t(Sec.getRawDataRefImpl().p) - uintptr_t(SectionTable);
assert((Offset % sizeof(coff_section)) == 0);
return (Offset / sizeof(coff_section)) + 1;
}
bool COFFObjectFile::isSectionVirtual(DataRefImpl Ref) const {
const coff_section *Sec = toSec(Ref);
// In COFF, a virtual section won't have any in-file
// content, so the file pointer to the content will be zero.
return Sec->PointerToRawData == 0;
}
static uint32_t getNumberOfRelocations(const coff_section *Sec,
MemoryBufferRef M, const uint8_t *base) {
// The field for the number of relocations in COFF section table is only
// 16-bit wide. If a section has more than 65535 relocations, 0xFFFF is set to
// NumberOfRelocations field, and the actual relocation count is stored in the
// VirtualAddress field in the first relocation entry.
if (Sec->hasExtendedRelocations()) {
const coff_relocation *FirstReloc;
if (getObject(FirstReloc, M, reinterpret_cast<const coff_relocation*>(
base + Sec->PointerToRelocations)))
return 0;
// -1 to exclude this first relocation entry.
return FirstReloc->VirtualAddress - 1;
}
return Sec->NumberOfRelocations;
}
static const coff_relocation *
getFirstReloc(const coff_section *Sec, MemoryBufferRef M, const uint8_t *Base) {
uint64_t NumRelocs = getNumberOfRelocations(Sec, M, Base);
if (!NumRelocs)
return nullptr;
auto begin = reinterpret_cast<const coff_relocation *>(
Base + Sec->PointerToRelocations);
if (Sec->hasExtendedRelocations()) {
// Skip the first relocation entry repurposed to store the number of
// relocations.
begin++;
}
if (Binary::checkOffset(M, uintptr_t(begin),
sizeof(coff_relocation) * NumRelocs))
return nullptr;
return begin;
}
relocation_iterator COFFObjectFile::section_rel_begin(DataRefImpl Ref) const {
const coff_section *Sec = toSec(Ref);
const coff_relocation *begin = getFirstReloc(Sec, Data, base());
if (begin && Sec->VirtualAddress != 0)
report_fatal_error("Sections with relocations should have an address of 0");
DataRefImpl Ret;
Ret.p = reinterpret_cast<uintptr_t>(begin);
return relocation_iterator(RelocationRef(Ret, this));
}
relocation_iterator COFFObjectFile::section_rel_end(DataRefImpl Ref) const {
const coff_section *Sec = toSec(Ref);
const coff_relocation *I = getFirstReloc(Sec, Data, base());
if (I)
I += getNumberOfRelocations(Sec, Data, base());
DataRefImpl Ret;
Ret.p = reinterpret_cast<uintptr_t>(I);
return relocation_iterator(RelocationRef(Ret, this));
}
// Initialize the pointer to the symbol table.
std::error_code COFFObjectFile::initSymbolTablePtr() {
if (COFFHeader)
if (std::error_code EC = getObject(
SymbolTable16, Data, base() + getPointerToSymbolTable(),
(uint64_t)getNumberOfSymbols() * getSymbolTableEntrySize()))
return EC;
if (COFFBigObjHeader)
if (std::error_code EC = getObject(
SymbolTable32, Data, base() + getPointerToSymbolTable(),
(uint64_t)getNumberOfSymbols() * getSymbolTableEntrySize()))
return EC;
// Find string table. The first four byte of the string table contains the
// total size of the string table, including the size field itself. If the
// string table is empty, the value of the first four byte would be 4.
uint32_t StringTableOffset = getPointerToSymbolTable() +
getNumberOfSymbols() * getSymbolTableEntrySize();
const uint8_t *StringTableAddr = base() + StringTableOffset;
const ulittle32_t *StringTableSizePtr;
if (std::error_code EC = getObject(StringTableSizePtr, Data, StringTableAddr))
return EC;
StringTableSize = *StringTableSizePtr;
if (std::error_code EC =
getObject(StringTable, Data, StringTableAddr, StringTableSize))
return EC;
// Treat table sizes < 4 as empty because contrary to the PECOFF spec, some
// tools like cvtres write a size of 0 for an empty table instead of 4.
if (StringTableSize < 4)
StringTableSize = 4;
// Check that the string table is null terminated if has any in it.
if (StringTableSize > 4 && StringTable[StringTableSize - 1] != 0)
return object_error::parse_failed;
return std::error_code();
}
uint64_t COFFObjectFile::getImageBase() const {
if (PE32Header)
return PE32Header->ImageBase;
else if (PE32PlusHeader)
return PE32PlusHeader->ImageBase;
// This actually comes up in practice.
return 0;
}
// Returns the file offset for the given VA.
std::error_code COFFObjectFile::getVaPtr(uint64_t Addr, uintptr_t &Res) const {
uint64_t ImageBase = getImageBase();
uint64_t Rva = Addr - ImageBase;
assert(Rva <= UINT32_MAX);
return getRvaPtr((uint32_t)Rva, Res);
}
// Returns the file offset for the given RVA.
std::error_code COFFObjectFile::getRvaPtr(uint32_t Addr, uintptr_t &Res) const {
for (const SectionRef &S : sections()) {
const coff_section *Section = getCOFFSection(S);
uint32_t SectionStart = Section->VirtualAddress;
uint32_t SectionEnd = Section->VirtualAddress + Section->VirtualSize;
if (SectionStart <= Addr && Addr < SectionEnd) {
uint32_t Offset = Addr - SectionStart;
Res = uintptr_t(base()) + Section->PointerToRawData + Offset;
return std::error_code();
}
}
return object_error::parse_failed;
}
std::error_code
COFFObjectFile::getRvaAndSizeAsBytes(uint32_t RVA, uint32_t Size,
ArrayRef<uint8_t> &Contents) const {
for (const SectionRef &S : sections()) {
const coff_section *Section = getCOFFSection(S);
uint32_t SectionStart = Section->VirtualAddress;
// Check if this RVA is within the section bounds. Be careful about integer
// overflow.
uint32_t OffsetIntoSection = RVA - SectionStart;
if (SectionStart <= RVA && OffsetIntoSection < Section->VirtualSize &&
Size <= Section->VirtualSize - OffsetIntoSection) {
uintptr_t Begin =
uintptr_t(base()) + Section->PointerToRawData + OffsetIntoSection;
Contents =
ArrayRef<uint8_t>(reinterpret_cast<const uint8_t *>(Begin), Size);
return std::error_code();
}
}
return object_error::parse_failed;
}
// Returns hint and name fields, assuming \p Rva is pointing to a Hint/Name
// table entry.
std::error_code COFFObjectFile::getHintName(uint32_t Rva, uint16_t &Hint,
StringRef &Name) const {
uintptr_t IntPtr = 0;
if (std::error_code EC = getRvaPtr(Rva, IntPtr))
return EC;
const uint8_t *Ptr = reinterpret_cast<const uint8_t *>(IntPtr);
Hint = *reinterpret_cast<const ulittle16_t *>(Ptr);
Name = StringRef(reinterpret_cast<const char *>(Ptr + 2));
return std::error_code();
}
std::error_code
COFFObjectFile::getDebugPDBInfo(const debug_directory *DebugDir,
const codeview::DebugInfo *&PDBInfo,
StringRef &PDBFileName) const {
ArrayRef<uint8_t> InfoBytes;
if (std::error_code EC = getRvaAndSizeAsBytes(
DebugDir->AddressOfRawData, DebugDir->SizeOfData, InfoBytes))
return EC;
if (InfoBytes.size() < sizeof(*PDBInfo) + 1)
return object_error::parse_failed;
PDBInfo = reinterpret_cast<const codeview::DebugInfo *>(InfoBytes.data());
InfoBytes = InfoBytes.drop_front(sizeof(*PDBInfo));
PDBFileName = StringRef(reinterpret_cast<const char *>(InfoBytes.data()),
InfoBytes.size());
// Truncate the name at the first null byte. Ignore any padding.
PDBFileName = PDBFileName.split('\0').first;
return std::error_code();
}
std::error_code
COFFObjectFile::getDebugPDBInfo(const codeview::DebugInfo *&PDBInfo,
StringRef &PDBFileName) const {
for (const debug_directory &D : debug_directories())
if (D.Type == COFF::IMAGE_DEBUG_TYPE_CODEVIEW)
return getDebugPDBInfo(&D, PDBInfo, PDBFileName);
// If we get here, there is no PDB info to return.
PDBInfo = nullptr;
PDBFileName = StringRef();
return std::error_code();
}
// Find the import table.
std::error_code COFFObjectFile::initImportTablePtr() {
// First, we get the RVA of the import table. If the file lacks a pointer to
// the import table, do nothing.
const data_directory *DataEntry;
if (getDataDirectory(COFF::IMPORT_TABLE, DataEntry))
return std::error_code();
// Do nothing if the pointer to import table is NULL.
if (DataEntry->RelativeVirtualAddress == 0)
return std::error_code();
uint32_t ImportTableRva = DataEntry->RelativeVirtualAddress;
// Find the section that contains the RVA. This is needed because the RVA is
// the import table's memory address which is different from its file offset.
uintptr_t IntPtr = 0;
if (std::error_code EC = getRvaPtr(ImportTableRva, IntPtr))
return EC;
if (std::error_code EC = checkOffset(Data, IntPtr, DataEntry->Size))
return EC;
ImportDirectory = reinterpret_cast<
const coff_import_directory_table_entry *>(IntPtr);
return std::error_code();
}
// Initializes DelayImportDirectory and NumberOfDelayImportDirectory.
std::error_code COFFObjectFile::initDelayImportTablePtr() {
const data_directory *DataEntry;
if (getDataDirectory(COFF::DELAY_IMPORT_DESCRIPTOR, DataEntry))
return std::error_code();
if (DataEntry->RelativeVirtualAddress == 0)
return std::error_code();
uint32_t RVA = DataEntry->RelativeVirtualAddress;
NumberOfDelayImportDirectory = DataEntry->Size /
sizeof(delay_import_directory_table_entry) - 1;
uintptr_t IntPtr = 0;
if (std::error_code EC = getRvaPtr(RVA, IntPtr))
return EC;
DelayImportDirectory = reinterpret_cast<
const delay_import_directory_table_entry *>(IntPtr);
return std::error_code();
}
// Find the export table.
std::error_code COFFObjectFile::initExportTablePtr() {
// First, we get the RVA of the export table. If the file lacks a pointer to
// the export table, do nothing.
const data_directory *DataEntry;
if (getDataDirectory(COFF::EXPORT_TABLE, DataEntry))
return std::error_code();
// Do nothing if the pointer to export table is NULL.
if (DataEntry->RelativeVirtualAddress == 0)
return std::error_code();
uint32_t ExportTableRva = DataEntry->RelativeVirtualAddress;
uintptr_t IntPtr = 0;
if (std::error_code EC = getRvaPtr(ExportTableRva, IntPtr))
return EC;
ExportDirectory =
reinterpret_cast<const export_directory_table_entry *>(IntPtr);
return std::error_code();
}
std::error_code COFFObjectFile::initBaseRelocPtr() {
const data_directory *DataEntry;
if (getDataDirectory(COFF::BASE_RELOCATION_TABLE, DataEntry))
return std::error_code();
if (DataEntry->RelativeVirtualAddress == 0)
return std::error_code();
uintptr_t IntPtr = 0;
if (std::error_code EC = getRvaPtr(DataEntry->RelativeVirtualAddress, IntPtr))
return EC;
BaseRelocHeader = reinterpret_cast<const coff_base_reloc_block_header *>(
IntPtr);
BaseRelocEnd = reinterpret_cast<coff_base_reloc_block_header *>(
IntPtr + DataEntry->Size);
// FIXME: Verify the section containing BaseRelocHeader has at least
// DataEntry->Size bytes after DataEntry->RelativeVirtualAddress.
return std::error_code();
}
std::error_code COFFObjectFile::initDebugDirectoryPtr() {
// Get the RVA of the debug directory. Do nothing if it does not exist.
const data_directory *DataEntry;
if (getDataDirectory(COFF::DEBUG_DIRECTORY, DataEntry))
return std::error_code();
// Do nothing if the RVA is NULL.
if (DataEntry->RelativeVirtualAddress == 0)
return std::error_code();
// Check that the size is a multiple of the entry size.
if (DataEntry->Size % sizeof(debug_directory) != 0)
return object_error::parse_failed;
uintptr_t IntPtr = 0;
if (std::error_code EC = getRvaPtr(DataEntry->RelativeVirtualAddress, IntPtr))
return EC;
DebugDirectoryBegin = reinterpret_cast<const debug_directory *>(IntPtr);
DebugDirectoryEnd = reinterpret_cast<const debug_directory *>(
IntPtr + DataEntry->Size);
// FIXME: Verify the section containing DebugDirectoryBegin has at least
// DataEntry->Size bytes after DataEntry->RelativeVirtualAddress.
return std::error_code();
}
std::error_code COFFObjectFile::initLoadConfigPtr() {
// Get the RVA of the debug directory. Do nothing if it does not exist.
const data_directory *DataEntry;
if (getDataDirectory(COFF::LOAD_CONFIG_TABLE, DataEntry))
return std::error_code();
// Do nothing if the RVA is NULL.
if (DataEntry->RelativeVirtualAddress == 0)
return std::error_code();
uintptr_t IntPtr = 0;
if (std::error_code EC = getRvaPtr(DataEntry->RelativeVirtualAddress, IntPtr))
return EC;
LoadConfig = (const void *)IntPtr;
return std::error_code();
}
Expected<std::unique_ptr<COFFObjectFile>>
COFFObjectFile::create(MemoryBufferRef Object) {
std::unique_ptr<COFFObjectFile> Obj(new COFFObjectFile(std::move(Object)));
if (Error E = Obj->initialize())
return std::move(E);
return std::move(Obj);
}
COFFObjectFile::COFFObjectFile(MemoryBufferRef Object)
: ObjectFile(Binary::ID_COFF, Object), COFFHeader(nullptr),
COFFBigObjHeader(nullptr), PE32Header(nullptr), PE32PlusHeader(nullptr),
DataDirectory(nullptr), SectionTable(nullptr), SymbolTable16(nullptr),
SymbolTable32(nullptr), StringTable(nullptr), StringTableSize(0),
ImportDirectory(nullptr), DelayImportDirectory(nullptr),
NumberOfDelayImportDirectory(0), ExportDirectory(nullptr),
BaseRelocHeader(nullptr), BaseRelocEnd(nullptr),
DebugDirectoryBegin(nullptr), DebugDirectoryEnd(nullptr) {}
Error COFFObjectFile::initialize() {
// Check that we at least have enough room for a header.
std::error_code EC;
if (!checkSize(Data, EC, sizeof(coff_file_header)))
return errorCodeToError(EC);
// The current location in the file where we are looking at.
uint64_t CurPtr = 0;
// PE header is optional and is present only in executables. If it exists,
// it is placed right after COFF header.
bool HasPEHeader = false;
// Check if this is a PE/COFF file.
if (checkSize(Data, EC, sizeof(dos_header) + sizeof(COFF::PEMagic))) {
// PE/COFF, seek through MS-DOS compatibility stub and 4-byte
// PE signature to find 'normal' COFF header.
const auto *DH = reinterpret_cast<const dos_header *>(base());
if (DH->Magic[0] == 'M' && DH->Magic[1] == 'Z') {
CurPtr = DH->AddressOfNewExeHeader;
// Check the PE magic bytes. ("PE\0\0")
if (memcmp(base() + CurPtr, COFF::PEMagic, sizeof(COFF::PEMagic)) != 0) {
return errorCodeToError(object_error::parse_failed);
}
CurPtr += sizeof(COFF::PEMagic); // Skip the PE magic bytes.
HasPEHeader = true;
}
}
if ((EC = getObject(COFFHeader, Data, base() + CurPtr)))
return errorCodeToError(EC);
// It might be a bigobj file, let's check. Note that COFF bigobj and COFF
// import libraries share a common prefix but bigobj is more restrictive.
if (!HasPEHeader && COFFHeader->Machine == COFF::IMAGE_FILE_MACHINE_UNKNOWN &&
COFFHeader->NumberOfSections == uint16_t(0xffff) &&
checkSize(Data, EC, sizeof(coff_bigobj_file_header))) {
if ((EC = getObject(COFFBigObjHeader, Data, base() + CurPtr)))
return errorCodeToError(EC);
// Verify that we are dealing with bigobj.
if (COFFBigObjHeader->Version >= COFF::BigObjHeader::MinBigObjectVersion &&
std::memcmp(COFFBigObjHeader->UUID, COFF::BigObjMagic,
sizeof(COFF::BigObjMagic)) == 0) {
COFFHeader = nullptr;
CurPtr += sizeof(coff_bigobj_file_header);
} else {
// It's not a bigobj.
COFFBigObjHeader = nullptr;
}
}
if (COFFHeader) {
// The prior checkSize call may have failed. This isn't a hard error
// because we were just trying to sniff out bigobj.
EC = std::error_code();
CurPtr += sizeof(coff_file_header);
if (COFFHeader->isImportLibrary())
return errorCodeToError(EC);
}
if (HasPEHeader) {
const pe32_header *Header;
if ((EC = getObject(Header, Data, base() + CurPtr)))
return errorCodeToError(EC);
const uint8_t *DataDirAddr;
uint64_t DataDirSize;
if (Header->Magic == COFF::PE32Header::PE32) {
PE32Header = Header;
DataDirAddr = base() + CurPtr + sizeof(pe32_header);
DataDirSize = sizeof(data_directory) * PE32Header->NumberOfRvaAndSize;
} else if (Header->Magic == COFF::PE32Header::PE32_PLUS) {
PE32PlusHeader = reinterpret_cast<const pe32plus_header *>(Header);
DataDirAddr = base() + CurPtr + sizeof(pe32plus_header);
DataDirSize = sizeof(data_directory) * PE32PlusHeader->NumberOfRvaAndSize;
} else {
// It's neither PE32 nor PE32+.
return errorCodeToError(object_error::parse_failed);
}
if ((EC = getObject(DataDirectory, Data, DataDirAddr, DataDirSize)))
return errorCodeToError(EC);
}
if (COFFHeader)
CurPtr += COFFHeader->SizeOfOptionalHeader;
if ((EC = getObject(SectionTable, Data, base() + CurPtr,
(uint64_t)getNumberOfSections() * sizeof(coff_section))))
return errorCodeToError(EC);
// Initialize the pointer to the symbol table.
if (getPointerToSymbolTable() != 0) {
if ((EC = initSymbolTablePtr())) {
SymbolTable16 = nullptr;
SymbolTable32 = nullptr;
StringTable = nullptr;
StringTableSize = 0;
}
} else {
// We had better not have any symbols if we don't have a symbol table.
if (getNumberOfSymbols() != 0) {
return errorCodeToError(object_error::parse_failed);
}
}
// Initialize the pointer to the beginning of the import table.
if ((EC = initImportTablePtr()))
return errorCodeToError(EC);
if ((EC = initDelayImportTablePtr()))
return errorCodeToError(EC);
// Initialize the pointer to the export table.
if ((EC = initExportTablePtr()))
return errorCodeToError(EC);
// Initialize the pointer to the base relocation table.
if ((EC = initBaseRelocPtr()))
return errorCodeToError(EC);
// Initialize the pointer to the export table.
if ((EC = initDebugDirectoryPtr()))
return errorCodeToError(EC);
if ((EC = initLoadConfigPtr()))
return errorCodeToError(EC);
return Error::success();
}
basic_symbol_iterator COFFObjectFile::symbol_begin() const {
DataRefImpl Ret;
Ret.p = getSymbolTable();
return basic_symbol_iterator(SymbolRef(Ret, this));
}
basic_symbol_iterator COFFObjectFile::symbol_end() const {
// The symbol table ends where the string table begins.
DataRefImpl Ret;
Ret.p = reinterpret_cast<uintptr_t>(StringTable);
return basic_symbol_iterator(SymbolRef(Ret, this));
}
import_directory_iterator COFFObjectFile::import_directory_begin() const {
if (!ImportDirectory)
return import_directory_end();
if (ImportDirectory->isNull())
return import_directory_end();
return import_directory_iterator(
ImportDirectoryEntryRef(ImportDirectory, 0, this));
}
import_directory_iterator COFFObjectFile::import_directory_end() const {
return import_directory_iterator(
ImportDirectoryEntryRef(nullptr, -1, this));
}
delay_import_directory_iterator
COFFObjectFile::delay_import_directory_begin() const {
return delay_import_directory_iterator(
DelayImportDirectoryEntryRef(DelayImportDirectory, 0, this));
}
delay_import_directory_iterator
COFFObjectFile::delay_import_directory_end() const {
return delay_import_directory_iterator(
DelayImportDirectoryEntryRef(
DelayImportDirectory, NumberOfDelayImportDirectory, this));
}
export_directory_iterator COFFObjectFile::export_directory_begin() const {
return export_directory_iterator(
ExportDirectoryEntryRef(ExportDirectory, 0, this));
}
export_directory_iterator COFFObjectFile::export_directory_end() const {
if (!ExportDirectory)
return export_directory_iterator(ExportDirectoryEntryRef(nullptr, 0, this));
ExportDirectoryEntryRef Ref(ExportDirectory,
ExportDirectory->AddressTableEntries, this);
return export_directory_iterator(Ref);
}
section_iterator COFFObjectFile::section_begin() const {
DataRefImpl Ret;
Ret.p = reinterpret_cast<uintptr_t>(SectionTable);
return section_iterator(SectionRef(Ret, this));
}
section_iterator COFFObjectFile::section_end() const {
DataRefImpl Ret;
int NumSections =
COFFHeader && COFFHeader->isImportLibrary() ? 0 : getNumberOfSections();
Ret.p = reinterpret_cast<uintptr_t>(SectionTable + NumSections);
return section_iterator(SectionRef(Ret, this));
}
base_reloc_iterator COFFObjectFile::base_reloc_begin() const {
return base_reloc_iterator(BaseRelocRef(BaseRelocHeader, this));
}
base_reloc_iterator COFFObjectFile::base_reloc_end() const {
return base_reloc_iterator(BaseRelocRef(BaseRelocEnd, this));
}
uint8_t COFFObjectFile::getBytesInAddress() const {
return getArch() == Triple::x86_64 || getArch() == Triple::aarch64 ? 8 : 4;
}
StringRef COFFObjectFile::getFileFormatName() const {
switch(getMachine()) {
case COFF::IMAGE_FILE_MACHINE_I386:
return "COFF-i386";
case COFF::IMAGE_FILE_MACHINE_AMD64:
return "COFF-x86-64";
case COFF::IMAGE_FILE_MACHINE_ARMNT:
return "COFF-ARM";
case COFF::IMAGE_FILE_MACHINE_ARM64:
return "COFF-ARM64";
default:
return "COFF-<unknown arch>";
}
}
Triple::ArchType COFFObjectFile::getArch() const {
switch (getMachine()) {
case COFF::IMAGE_FILE_MACHINE_I386:
return Triple::x86;
case COFF::IMAGE_FILE_MACHINE_AMD64:
return Triple::x86_64;
case COFF::IMAGE_FILE_MACHINE_ARMNT:
return Triple::thumb;
case COFF::IMAGE_FILE_MACHINE_ARM64:
return Triple::aarch64;
default:
return Triple::UnknownArch;
}
}
Expected<uint64_t> COFFObjectFile::getStartAddress() const {
if (PE32Header)
return PE32Header->AddressOfEntryPoint;
return 0;
}
iterator_range<import_directory_iterator>
COFFObjectFile::import_directories() const {
return make_range(import_directory_begin(), import_directory_end());
}
iterator_range<delay_import_directory_iterator>
COFFObjectFile::delay_import_directories() const {
return make_range(delay_import_directory_begin(),
delay_import_directory_end());
}
iterator_range<export_directory_iterator>
COFFObjectFile::export_directories() const {
return make_range(export_directory_begin(), export_directory_end());
}
iterator_range<base_reloc_iterator> COFFObjectFile::base_relocs() const {
return make_range(base_reloc_begin(), base_reloc_end());
}
std::error_code
COFFObjectFile::getDataDirectory(uint32_t Index,
const data_directory *&Res) const {
// Error if there's no data directory or the index is out of range.
if (!DataDirectory) {
Res = nullptr;
return object_error::parse_failed;
}
assert(PE32Header || PE32PlusHeader);
uint32_t NumEnt = PE32Header ? PE32Header->NumberOfRvaAndSize
: PE32PlusHeader->NumberOfRvaAndSize;
if (Index >= NumEnt) {
Res = nullptr;
return object_error::parse_failed;
}
Res = &DataDirectory[Index];
return std::error_code();
}
Expected<const coff_section *> COFFObjectFile::getSection(int32_t Index) const {
// Perhaps getting the section of a reserved section index should be an error,
// but callers rely on this to return null.
if (COFF::isReservedSectionNumber(Index))
return (const coff_section *)nullptr;
if (static_cast<uint32_t>(Index) <= getNumberOfSections()) {
// We already verified the section table data, so no need to check again.
return SectionTable + (Index - 1);
}
return errorCodeToError(object_error::parse_failed);
}
Expected<StringRef> COFFObjectFile::getString(uint32_t Offset) const {
if (StringTableSize <= 4)
// Tried to get a string from an empty string table.
return errorCodeToError(object_error::parse_failed);
if (Offset >= StringTableSize)
return errorCodeToError(object_error::unexpected_eof);
return StringRef(StringTable + Offset);
}
Expected<StringRef> COFFObjectFile::getSymbolName(COFFSymbolRef Symbol) const {
return getSymbolName(Symbol.getGeneric());
}
Expected<StringRef>
COFFObjectFile::getSymbolName(const coff_symbol_generic *Symbol) const {
// Check for string table entry. First 4 bytes are 0.
if (Symbol->Name.Offset.Zeroes == 0)
return getString(Symbol->Name.Offset.Offset);
// Null terminated, let ::strlen figure out the length.