llvm/lib/Object/COFFObjectFile.cpp
Nick Lewycky 71f234ba6a Remove dead variable pointed out by GCC 4.6 warnings, and reflow this a little
to scope a variable more tightly per llvm coding style. No functional change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130684 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-02 05:05:29 +00:00

389 lines
12 KiB
C++

//===- 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/ADT/StringSwitch.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/COFF.h"
#include "llvm/Support/Endian.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 {
struct coff_file_header {
ulittle16_t Machine;
ulittle16_t NumberOfSections;
ulittle32_t TimeDateStamp;
ulittle32_t PointerToSymbolTable;
ulittle32_t NumberOfSymbols;
ulittle16_t SizeOfOptionalHeader;
ulittle16_t Characteristics;
};
}
extern char coff_file_header_layout_static_assert
[sizeof(coff_file_header) == 20 ? 1 : -1];
namespace {
struct coff_symbol {
struct StringTableOffset {
ulittle32_t Zeroes;
ulittle32_t Offset;
};
union {
char ShortName[8];
StringTableOffset Offset;
} Name;
ulittle32_t Value;
little16_t SectionNumber;
struct {
ulittle8_t BaseType;
ulittle8_t ComplexType;
} Type;
ulittle8_t StorageClass;
ulittle8_t NumberOfAuxSymbols;
};
}
extern char coff_coff_symbol_layout_static_assert
[sizeof(coff_symbol) == 18 ? 1 : -1];
namespace {
struct coff_section {
char Name[8];
ulittle32_t VirtualSize;
ulittle32_t VirtualAddress;
ulittle32_t SizeOfRawData;
ulittle32_t PointerToRawData;
ulittle32_t PointerToRelocations;
ulittle32_t PointerToLinenumbers;
ulittle16_t NumberOfRelocations;
ulittle16_t NumberOfLinenumbers;
ulittle32_t Characteristics;
};
}
extern char coff_coff_section_layout_static_assert
[sizeof(coff_section) == 40 ? 1 : -1];
namespace {
class COFFObjectFile : public ObjectFile {
private:
uint64_t HeaderOff;
const coff_file_header *Header;
const coff_section *SectionTable;
const coff_symbol *SymbolTable;
const char *StringTable;
const coff_section *getSection(std::size_t index) const;
const char *getString(std::size_t offset) const;
protected:
virtual SymbolRef getSymbolNext(DataRefImpl Symb) const;
virtual StringRef getSymbolName(DataRefImpl Symb) const;
virtual uint64_t getSymbolAddress(DataRefImpl Symb) const;
virtual uint64_t getSymbolSize(DataRefImpl Symb) const;
virtual char getSymbolNMTypeChar(DataRefImpl Symb) const;
virtual bool isSymbolInternal(DataRefImpl Symb) const;
virtual SectionRef getSectionNext(DataRefImpl Sec) const;
virtual StringRef getSectionName(DataRefImpl Sec) const;
virtual uint64_t getSectionAddress(DataRefImpl Sec) const;
virtual uint64_t getSectionSize(DataRefImpl Sec) const;
virtual StringRef getSectionContents(DataRefImpl Sec) const;
virtual bool isSectionText(DataRefImpl Sec) const;
public:
COFFObjectFile(MemoryBuffer *Object);
virtual symbol_iterator begin_symbols() const;
virtual symbol_iterator end_symbols() const;
virtual section_iterator begin_sections() const;
virtual section_iterator end_sections() const;
virtual uint8_t getBytesInAddress() const;
virtual StringRef getFileFormatName() const;
virtual unsigned getArch() const;
};
} // end namespace
SymbolRef COFFObjectFile::getSymbolNext(DataRefImpl Symb) const {
const coff_symbol *symb = reinterpret_cast<const coff_symbol*>(Symb.p);
symb += 1 + symb->NumberOfAuxSymbols;
Symb.p = reinterpret_cast<intptr_t>(symb);
return SymbolRef(Symb, this);
}
StringRef COFFObjectFile::getSymbolName(DataRefImpl Symb) const {
const coff_symbol *symb = reinterpret_cast<const coff_symbol*>(Symb.p);
// Check for string table entry. First 4 bytes are 0.
if (symb->Name.Offset.Zeroes == 0) {
uint32_t Offset = symb->Name.Offset.Offset;
return StringRef(getString(Offset));
}
if (symb->Name.ShortName[7] == 0)
// Null terminated, let ::strlen figure out the length.
return StringRef(symb->Name.ShortName);
// Not null terminated, use all 8 bytes.
return StringRef(symb->Name.ShortName, 8);
}
uint64_t COFFObjectFile::getSymbolAddress(DataRefImpl Symb) const {
const coff_symbol *symb = reinterpret_cast<const coff_symbol*>(Symb.p);
const coff_section *Section = getSection(symb->SectionNumber);
char Type = getSymbolNMTypeChar(Symb);
if (Type == 'U' || Type == 'w')
return UnknownAddressOrSize;
if (Section)
return Section->VirtualAddress + symb->Value;
return symb->Value;
}
uint64_t COFFObjectFile::getSymbolSize(DataRefImpl Symb) 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 = reinterpret_cast<const coff_symbol*>(Symb.p);
const coff_section *Section = getSection(symb->SectionNumber);
char Type = getSymbolNMTypeChar(Symb);
if (Type == 'U' || Type == 'w')
return UnknownAddressOrSize;
if (Section)
return Section->SizeOfRawData - symb->Value;
return 0;
}
char COFFObjectFile::getSymbolNMTypeChar(DataRefImpl Symb) const {
const coff_symbol *symb = reinterpret_cast<const coff_symbol*>(Symb.p);
char ret = StringSwitch<char>(getSymbolName(Symb))
.StartsWith(".debug", 'N')
.StartsWith(".sxdata", 'N')
.Default('?');
if (ret != '?')
return ret;
uint32_t Characteristics = 0;
if (const coff_section *Section = getSection(symb->SectionNumber)) {
Characteristics = Section->Characteristics;
}
switch (symb->SectionNumber) {
case COFF::IMAGE_SYM_UNDEFINED:
// Check storage classes.
if (symb->StorageClass == COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL)
return 'w'; // 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);
return ret;
}
bool COFFObjectFile::isSymbolInternal(DataRefImpl Symb) const {
return false;
}
SectionRef COFFObjectFile::getSectionNext(DataRefImpl Sec) const {
const coff_section *sec = reinterpret_cast<const coff_section*>(Sec.p);
sec += 1;
Sec.p = reinterpret_cast<intptr_t>(sec);
return SectionRef(Sec, this);
}
StringRef COFFObjectFile::getSectionName(DataRefImpl Sec) const {
const coff_section *sec = reinterpret_cast<const coff_section*>(Sec.p);
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);
return StringRef(getString(Offset));
}
// It's just a normal name.
return name;
}
uint64_t COFFObjectFile::getSectionAddress(DataRefImpl Sec) const {
const coff_section *sec = reinterpret_cast<const coff_section*>(Sec.p);
return sec->VirtualAddress;
}
uint64_t COFFObjectFile::getSectionSize(DataRefImpl Sec) const {
const coff_section *sec = reinterpret_cast<const coff_section*>(Sec.p);
return sec->SizeOfRawData;
}
StringRef COFFObjectFile::getSectionContents(DataRefImpl Sec) const {
const coff_section *sec = reinterpret_cast<const coff_section*>(Sec.p);
return StringRef(reinterpret_cast<const char *>(base + sec->PointerToRawData),
sec->SizeOfRawData);
}
bool COFFObjectFile::isSectionText(DataRefImpl Sec) const {
const coff_section *sec = reinterpret_cast<const coff_section*>(Sec.p);
return sec->Characteristics & COFF::IMAGE_SCN_CNT_CODE;
}
COFFObjectFile::COFFObjectFile(MemoryBuffer *Object)
: ObjectFile(Object) {
HeaderOff = 0;
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.
HeaderOff += *reinterpret_cast<const ulittle32_t *>(base + 0x3c);
HeaderOff += 4;
}
Header = reinterpret_cast<const coff_file_header *>(base + HeaderOff);
SectionTable =
reinterpret_cast<const coff_section *>( base
+ HeaderOff
+ sizeof(coff_file_header)
+ Header->SizeOfOptionalHeader);
SymbolTable =
reinterpret_cast<const coff_symbol *>(base + Header->PointerToSymbolTable);
// Find string table.
StringTable = reinterpret_cast<const char *>(base)
+ Header->PointerToSymbolTable
+ Header->NumberOfSymbols * 18;
}
ObjectFile::symbol_iterator COFFObjectFile::begin_symbols() const {
DataRefImpl ret;
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;
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;
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;
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;
}
}
const coff_section *COFFObjectFile::getSection(std::size_t index) const {
if (index > 0 && index <= Header->NumberOfSections)
return SectionTable + (index - 1);
return 0;
}
const char *COFFObjectFile::getString(std::size_t offset) const {
const ulittle32_t *StringTableSize =
reinterpret_cast<const ulittle32_t *>(StringTable);
if (offset < *StringTableSize)
return StringTable + offset;
return 0;
}
namespace llvm {
ObjectFile *ObjectFile::createCOFFObjectFile(MemoryBuffer *Object) {
return new COFFObjectFile(Object);
}
} // end namespace llvm