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

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//===- COFFObjectFile.cpp - COFF object file implementation -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the COFFObjectFile class.
//
//===----------------------------------------------------------------------===//
#include "llvm/Object/COFF.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/Triple.h"
using namespace llvm;
using namespace object;
namespace {
using support::ulittle8_t;
using support::ulittle16_t;
using support::ulittle32_t;
using support::little16_t;
}
namespace {
// Returns false if size is greater than the buffer size. And sets ec.
bool checkSize(const MemoryBuffer *m, error_code &ec, uint64_t size) {
if (m->getBufferSize() < size) {
ec = object_error::unexpected_eof;
return false;
}
return true;
}
// Returns false if any bytes in [addr, addr + size) fall outsize of m.
bool checkAddr(const MemoryBuffer *m,
error_code &ec,
uintptr_t addr,
uint64_t size) {
if (addr + size < addr ||
addr + size < size ||
addr + size > uintptr_t(m->getBufferEnd())) {
ec = object_error::unexpected_eof;
return false;
}
return true;
}
}
const coff_symbol *COFFObjectFile::toSymb(DataRefImpl Symb) const {
const coff_symbol *addr = reinterpret_cast<const coff_symbol*>(Symb.p);
# ifndef NDEBUG
// Verify that the symbol points to a valid entry in the symbol table.
uintptr_t offset = uintptr_t(addr) - uintptr_t(base());
if (offset < Header->PointerToSymbolTable
|| offset >= Header->PointerToSymbolTable
+ (Header->NumberOfSymbols * sizeof(coff_symbol)))
report_fatal_error("Symbol was outside of symbol table.");
assert((offset - Header->PointerToSymbolTable) % sizeof(coff_symbol)
== 0 && "Symbol did not point to the beginning of a symbol");
# endif
return addr;
}
const coff_section *COFFObjectFile::toSec(DataRefImpl Sec) const {
const coff_section *addr = reinterpret_cast<const coff_section*>(Sec.p);
# ifndef NDEBUG
// Verify that the section points to a valid entry in the section table.
if (addr < SectionTable
|| addr >= (SectionTable + Header->NumberOfSections))
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;
}
error_code COFFObjectFile::getSymbolNext(DataRefImpl Symb,
SymbolRef &Result) const {
const coff_symbol *symb = toSymb(Symb);
symb += 1 + symb->NumberOfAuxSymbols;
Symb.p = reinterpret_cast<uintptr_t>(symb);
Result = SymbolRef(Symb, this);
return object_error::success;
}
error_code COFFObjectFile::getSymbolName(DataRefImpl Symb,
StringRef &Result) const {
const coff_symbol *symb = toSymb(Symb);
// Check for string table entry. First 4 bytes are 0.
if (symb->Name.Offset.Zeroes == 0) {
uint32_t Offset = symb->Name.Offset.Offset;
if (error_code ec = getString(Offset, Result))
return ec;
return object_error::success;
}
if (symb->Name.ShortName[7] == 0)
// Null terminated, let ::strlen figure out the length.
Result = StringRef(symb->Name.ShortName);
else
// Not null terminated, use all 8 bytes.
Result = StringRef(symb->Name.ShortName, 8);
return object_error::success;
}
error_code COFFObjectFile::getSymbolAddress(DataRefImpl Symb,
uint64_t &Result) const {
const coff_symbol *symb = toSymb(Symb);
const coff_section *Section = NULL;
if (error_code ec = getSection(symb->SectionNumber, Section))
return ec;
char Type;
if (error_code ec = getSymbolNMTypeChar(Symb, Type))
return ec;
if (Type == 'U' || Type == 'w')
Result = UnknownAddressOrSize;
else if (Section)
Result = Section->VirtualAddress + symb->Value;
else
Result = symb->Value;
return object_error::success;
}
error_code COFFObjectFile::getSymbolSize(DataRefImpl Symb,
uint64_t &Result) const {
// FIXME: Return the correct size. This requires looking at all the symbols
// in the same section as this symbol, and looking for either the next
// symbol, or the end of the section.
const coff_symbol *symb = toSymb(Symb);
const coff_section *Section = NULL;
if (error_code ec = getSection(symb->SectionNumber, Section))
return ec;
char Type;
if (error_code ec = getSymbolNMTypeChar(Symb, Type))
return ec;
if (Type == 'U' || Type == 'w')
Result = UnknownAddressOrSize;
else if (Section)
Result = Section->SizeOfRawData - symb->Value;
else
Result = 0;
return object_error::success;
}
error_code COFFObjectFile::getSymbolNMTypeChar(DataRefImpl Symb,
char &Result) const {
const coff_symbol *symb = toSymb(Symb);
StringRef name;
if (error_code ec = getSymbolName(Symb, name))
return ec;
char ret = StringSwitch<char>(name)
.StartsWith(".debug", 'N')
.StartsWith(".sxdata", 'N')
.Default('?');
if (ret != '?') {
Result = ret;
return object_error::success;
}
uint32_t Characteristics = 0;
if (symb->SectionNumber > 0) {
const coff_section *Section = NULL;
if (error_code ec = getSection(symb->SectionNumber, Section))
return ec;
Characteristics = Section->Characteristics;
}
switch (symb->SectionNumber) {
case COFF::IMAGE_SYM_UNDEFINED:
// Check storage classes.
if (symb->StorageClass == COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL) {
Result = 'w';
return object_error::success; // Don't do ::toupper.
} else
ret = 'u';
break;
case COFF::IMAGE_SYM_ABSOLUTE:
ret = 'a';
break;
case COFF::IMAGE_SYM_DEBUG:
ret = 'n';
break;
default:
// Check section type.
if (Characteristics & COFF::IMAGE_SCN_CNT_CODE)
ret = 't';
else if ( Characteristics & COFF::IMAGE_SCN_MEM_READ
&& ~Characteristics & COFF::IMAGE_SCN_MEM_WRITE) // Read only.
ret = 'r';
else if (Characteristics & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
ret = 'd';
else if (Characteristics & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA)
ret = 'b';
else if (Characteristics & COFF::IMAGE_SCN_LNK_INFO)
ret = 'i';
// Check for section symbol.
else if ( symb->StorageClass == COFF::IMAGE_SYM_CLASS_STATIC
&& symb->Value == 0)
ret = 's';
}
if (symb->StorageClass == COFF::IMAGE_SYM_CLASS_EXTERNAL)
ret = ::toupper(ret);
Result = ret;
return object_error::success;
}
error_code COFFObjectFile::isSymbolInternal(DataRefImpl Symb,
bool &Result) const {
Result = false;
return object_error::success;
}
error_code COFFObjectFile::getSectionNext(DataRefImpl Sec,
SectionRef &Result) const {
const coff_section *sec = toSec(Sec);
sec += 1;
Sec.p = reinterpret_cast<uintptr_t>(sec);
Result = SectionRef(Sec, this);
return object_error::success;
}
error_code COFFObjectFile::getSectionName(DataRefImpl Sec,
StringRef &Result) const {
const coff_section *sec = toSec(Sec);
StringRef name;
if (sec->Name[7] == 0)
// Null terminated, let ::strlen figure out the length.
name = sec->Name;
else
// Not null terminated, use all 8 bytes.
name = StringRef(sec->Name, 8);
// Check for string table entry. First byte is '/'.
if (name[0] == '/') {
uint32_t Offset;
name.substr(1).getAsInteger(10, Offset);
if (error_code ec = getString(Offset, name))
return ec;
}
Result = name;
return object_error::success;
}
error_code COFFObjectFile::getSectionAddress(DataRefImpl Sec,
uint64_t &Result) const {
const coff_section *sec = toSec(Sec);
Result = sec->VirtualAddress;
return object_error::success;
}
error_code COFFObjectFile::getSectionSize(DataRefImpl Sec,
uint64_t &Result) const {
const coff_section *sec = toSec(Sec);
Result = sec->SizeOfRawData;
return object_error::success;
}
error_code COFFObjectFile::getSectionContents(DataRefImpl Sec,
StringRef &Result) const {
const coff_section *sec = toSec(Sec);
// The only thing that we need to verify is that the contents is contained
// within the file bounds. We don't need to make sure it doesn't cover other
// data, as there's nothing that says that is not allowed.
uintptr_t con_start = uintptr_t(base()) + sec->PointerToRawData;
uintptr_t con_end = con_start + sec->SizeOfRawData;
if (con_end >= uintptr_t(Data->getBufferEnd()))
return object_error::parse_failed;
Result = StringRef(reinterpret_cast<const char*>(con_start),
sec->SizeOfRawData);
return object_error::success;
}
error_code COFFObjectFile::isSectionText(DataRefImpl Sec,
bool &Result) const {
const coff_section *sec = toSec(Sec);
Result = sec->Characteristics & COFF::IMAGE_SCN_CNT_CODE;
return object_error::success;
}
error_code COFFObjectFile::sectionContainsSymbol(DataRefImpl Sec,
DataRefImpl Symb,
bool &Result) const {
// FIXME: Unimplemented.
Result = false;
return object_error::success;
}
COFFObjectFile::COFFObjectFile(MemoryBuffer *Object, error_code &ec)
: ObjectFile(Binary::isCOFF, Object, ec) {
// Check that we at least have enough room for a header.
if (!checkSize(Data, ec, sizeof(coff_file_header))) return;
// The actual starting location of the COFF header in the file. This can be
// non-zero in PE/COFF files.
uint64_t HeaderStart = 0;
// Check if this is a PE/COFF file.
if (base()[0] == 0x4d && base()[1] == 0x5a) {
// PE/COFF, seek through MS-DOS compatibility stub and 4-byte
// PE signature to find 'normal' COFF header.
if (!checkSize(Data, ec, 0x3c + 8)) return;
HeaderStart += *reinterpret_cast<const ulittle32_t *>(base() + 0x3c);
// Check the PE header. ("PE\0\0")
if (std::memcmp(base() + HeaderStart, "PE\0\0", 4) != 0) {
ec = object_error::parse_failed;
return;
}
HeaderStart += 4; // Skip the PE Header.
}
Header = reinterpret_cast<const coff_file_header *>(base() + HeaderStart);
if (!checkAddr(Data, ec, uintptr_t(Header), sizeof(coff_file_header)))
return;
SectionTable =
reinterpret_cast<const coff_section *>( base()
+ HeaderStart
+ sizeof(coff_file_header)
+ Header->SizeOfOptionalHeader);
if (!checkAddr(Data, ec, uintptr_t(SectionTable),
Header->NumberOfSections * sizeof(coff_section)))
return;
SymbolTable =
reinterpret_cast<const coff_symbol *>(base()
+ Header->PointerToSymbolTable);
if (!checkAddr(Data, ec, uintptr_t(SymbolTable),
Header->NumberOfSymbols * sizeof(coff_symbol)))
return;
// Find string table.
StringTable = reinterpret_cast<const char *>(base())
+ Header->PointerToSymbolTable
+ Header->NumberOfSymbols * sizeof(coff_symbol);
if (!checkAddr(Data, ec, uintptr_t(StringTable), sizeof(ulittle32_t)))
return;
StringTableSize = *reinterpret_cast<const ulittle32_t *>(StringTable);
if (!checkAddr(Data, ec, uintptr_t(StringTable), StringTableSize))
return;
// Check that the string table is null terminated if has any in it.
if (StringTableSize < 4
|| (StringTableSize > 4 && StringTable[StringTableSize - 1] != 0)) {
ec = object_error::parse_failed;
return;
}
ec = object_error::success;
}
ObjectFile::symbol_iterator COFFObjectFile::begin_symbols() const {
DataRefImpl ret;
std::memset(&ret, 0, sizeof(DataRefImpl));
ret.p = reinterpret_cast<intptr_t>(SymbolTable);
return symbol_iterator(SymbolRef(ret, this));
}
ObjectFile::symbol_iterator COFFObjectFile::end_symbols() const {
// The symbol table ends where the string table begins.
DataRefImpl ret;
std::memset(&ret, 0, sizeof(DataRefImpl));
ret.p = reinterpret_cast<intptr_t>(StringTable);
return symbol_iterator(SymbolRef(ret, this));
}
ObjectFile::section_iterator COFFObjectFile::begin_sections() const {
DataRefImpl ret;
std::memset(&ret, 0, sizeof(DataRefImpl));
ret.p = reinterpret_cast<intptr_t>(SectionTable);
return section_iterator(SectionRef(ret, this));
}
ObjectFile::section_iterator COFFObjectFile::end_sections() const {
DataRefImpl ret;
std::memset(&ret, 0, sizeof(DataRefImpl));
ret.p = reinterpret_cast<intptr_t>(SectionTable + Header->NumberOfSections);
return section_iterator(SectionRef(ret, this));
}
uint8_t COFFObjectFile::getBytesInAddress() const {
return getArch() == Triple::x86_64 ? 8 : 4;
}
StringRef COFFObjectFile::getFileFormatName() const {
switch(Header->Machine) {
case COFF::IMAGE_FILE_MACHINE_I386:
return "COFF-i386";
case COFF::IMAGE_FILE_MACHINE_AMD64:
return "COFF-x86-64";
default:
return "COFF-<unknown arch>";
}
}
unsigned COFFObjectFile::getArch() const {
switch(Header->Machine) {
case COFF::IMAGE_FILE_MACHINE_I386:
return Triple::x86;
case COFF::IMAGE_FILE_MACHINE_AMD64:
return Triple::x86_64;
default:
return Triple::UnknownArch;
}
}
error_code COFFObjectFile::getSection(int32_t index,
const coff_section *&Result) const {
// Check for special index values.
if (index == COFF::IMAGE_SYM_UNDEFINED ||
index == COFF::IMAGE_SYM_ABSOLUTE ||
index == COFF::IMAGE_SYM_DEBUG)
Result = NULL;
else if (index > 0 && index <= Header->NumberOfSections)
// We already verified the section table data, so no need to check again.
Result = SectionTable + (index - 1);
else
return object_error::parse_failed;
return object_error::success;
}
error_code COFFObjectFile::getString(uint32_t offset,
StringRef &Result) const {
if (StringTableSize <= 4)
// Tried to get a string from an empty string table.
return object_error::parse_failed;
if (offset >= StringTableSize)
return object_error::unexpected_eof;
Result = StringRef(StringTable + offset);
return object_error::success;
}
namespace llvm {
ObjectFile *ObjectFile::createCOFFObjectFile(MemoryBuffer *Object) {
error_code ec;
return new COFFObjectFile(Object, ec);
}
} // end namespace llvm
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