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llvm-project/llvm/tools/yaml2obj/yaml2coff.cpp

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//===- yaml2coff - Convert YAML to a COFF object file ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief The COFF component of yaml2obj.
///
//===----------------------------------------------------------------------===//
#include "yaml2obj.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Object/COFFYAML.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/raw_ostream.h"
#include <vector>
using namespace llvm;
/// This parses a yaml stream that represents a COFF object file.
/// See docs/yaml2obj for the yaml scheema.
struct COFFParser {
COFFParser(COFFYAML::Object &Obj) : Obj(Obj) {
// A COFF string table always starts with a 4 byte size field. Offsets into
// it include this size, so allocate it now.
StringTable.append(4, char(0));
}
bool parseSections() {
for (std::vector<COFFYAML::Section>::iterator i = Obj.Sections.begin(),
e = Obj.Sections.end(); i != e; ++i) {
COFFYAML::Section &Sec = *i;
// If the name is less than 8 bytes, store it in place, otherwise
// store it in the string table.
StringRef Name = Sec.Name;
if (Name.size() <= COFF::NameSize) {
std::copy(Name.begin(), Name.end(), Sec.Header.Name);
} else {
// Add string to the string table and format the index for output.
unsigned Index = getStringIndex(Name);
std::string str = utostr(Index);
if (str.size() > 7) {
errs() << "String table got too large";
return false;
}
Sec.Header.Name[0] = '/';
std::copy(str.begin(), str.end(), Sec.Header.Name + 1);
}
Sec.Header.Characteristics |= (Log2_32(Sec.Alignment) + 1) << 20;
}
return true;
}
bool parseSymbols() {
for (std::vector<COFFYAML::Symbol>::iterator i = Obj.Symbols.begin(),
e = Obj.Symbols.end(); i != e; ++i) {
COFFYAML::Symbol &Sym = *i;
// If the name is less than 8 bytes, store it in place, otherwise
// store it in the string table.
StringRef Name = Sym.Name;
if (Name.size() <= COFF::NameSize) {
std::copy(Name.begin(), Name.end(), Sym.Header.Name);
} else {
// Add string to the string table and format the index for output.
unsigned Index = getStringIndex(Name);
*reinterpret_cast<support::aligned_ulittle32_t*>(
Sym.Header.Name + 4) = Index;
}
Sym.Header.Type = Sym.SimpleType;
Sym.Header.Type |= Sym.ComplexType << COFF::SCT_COMPLEX_TYPE_SHIFT;
}
return true;
}
bool parse() {
if (!parseSections())
return false;
if (!parseSymbols())
return false;
return true;
}
unsigned getStringIndex(StringRef Str) {
StringMap<unsigned>::iterator i = StringTableMap.find(Str);
if (i == StringTableMap.end()) {
unsigned Index = StringTable.size();
StringTable.append(Str.begin(), Str.end());
StringTable.push_back(0);
StringTableMap[Str] = Index;
return Index;
}
return i->second;
}
COFFYAML::Object &Obj;
StringMap<unsigned> StringTableMap;
std::string StringTable;
};
// Take a CP and assign addresses and sizes to everything. Returns false if the
// layout is not valid to do.
static bool layoutCOFF(COFFParser &CP) {
uint32_t SectionTableStart = 0;
uint32_t SectionTableSize = 0;
// The section table starts immediately after the header, including the
// optional header.
SectionTableStart = sizeof(COFF::header) + CP.Obj.Header.SizeOfOptionalHeader;
SectionTableSize = sizeof(COFF::section) * CP.Obj.Sections.size();
uint32_t CurrentSectionDataOffset = SectionTableStart + SectionTableSize;
// Assign each section data address consecutively.
for (std::vector<COFFYAML::Section>::iterator i = CP.Obj.Sections.begin(),
e = CP.Obj.Sections.end();
i != e; ++i) {
if (i->SectionData.binary_size() > 0) {
i->Header.SizeOfRawData = i->SectionData.binary_size();
i->Header.PointerToRawData = CurrentSectionDataOffset;
CurrentSectionDataOffset += i->Header.SizeOfRawData;
if (!i->Relocations.empty()) {
i->Header.PointerToRelocations = CurrentSectionDataOffset;
i->Header.NumberOfRelocations = i->Relocations.size();
CurrentSectionDataOffset += i->Header.NumberOfRelocations *
COFF::RelocationSize;
}
// TODO: Handle alignment.
} else {
i->Header.SizeOfRawData = 0;
i->Header.PointerToRawData = 0;
}
}
uint32_t SymbolTableStart = CurrentSectionDataOffset;
// Calculate number of symbols.
uint32_t NumberOfSymbols = 0;
for (std::vector<COFFYAML::Symbol>::iterator i = CP.Obj.Symbols.begin(),
e = CP.Obj.Symbols.end();
i != e; ++i) {
uint32_t NumberOfAuxSymbols = 0;
if (i->FunctionDefinition)
NumberOfAuxSymbols += 1;
if (i->bfAndefSymbol)
NumberOfAuxSymbols += 1;
if (i->WeakExternal)
NumberOfAuxSymbols += 1;
if (!i->File.empty())
NumberOfAuxSymbols +=
(i->File.size() + COFF::SymbolSize - 1) / COFF::SymbolSize;
if (i->SectionDefinition)
NumberOfAuxSymbols += 1;
if (i->CLRToken)
NumberOfAuxSymbols += 1;
i->Header.NumberOfAuxSymbols = NumberOfAuxSymbols;
NumberOfSymbols += 1 + NumberOfAuxSymbols;
}
// Store all the allocated start addresses in the header.
CP.Obj.Header.NumberOfSections = CP.Obj.Sections.size();
CP.Obj.Header.NumberOfSymbols = NumberOfSymbols;
CP.Obj.Header.PointerToSymbolTable = SymbolTableStart;
*reinterpret_cast<support::ulittle32_t *>(&CP.StringTable[0])
= CP.StringTable.size();
return true;
}
template <typename value_type>
struct binary_le_impl {
value_type Value;
binary_le_impl(value_type V) : Value(V) {}
};
template <typename value_type>
raw_ostream &operator <<( raw_ostream &OS
, const binary_le_impl<value_type> &BLE) {
char Buffer[sizeof(BLE.Value)];
support::endian::write<value_type, support::little, support::unaligned>(
Buffer, BLE.Value);
OS.write(Buffer, sizeof(BLE.Value));
return OS;
}
template <typename value_type>
binary_le_impl<value_type> binary_le(value_type V) {
return binary_le_impl<value_type>(V);
}
template <size_t NumBytes>
struct zeros_impl {
zeros_impl() {}
};
template <size_t NumBytes>
raw_ostream &operator<<(raw_ostream &OS, const zeros_impl<NumBytes> &) {
char Buffer[NumBytes];
memset(Buffer, 0, sizeof(Buffer));
OS.write(Buffer, sizeof(Buffer));
return OS;
}
template <typename T>
zeros_impl<sizeof(T)> zeros(const T &) {
return zeros_impl<sizeof(T)>();
}
bool writeCOFF(COFFParser &CP, raw_ostream &OS) {
OS << binary_le(CP.Obj.Header.Machine)
<< binary_le(CP.Obj.Header.NumberOfSections)
<< binary_le(CP.Obj.Header.TimeDateStamp)
<< binary_le(CP.Obj.Header.PointerToSymbolTable)
<< binary_le(CP.Obj.Header.NumberOfSymbols)
<< binary_le(CP.Obj.Header.SizeOfOptionalHeader)
<< binary_le(CP.Obj.Header.Characteristics);
// Output section table.
for (std::vector<COFFYAML::Section>::iterator i = CP.Obj.Sections.begin(),
e = CP.Obj.Sections.end();
i != e; ++i) {
OS.write(i->Header.Name, COFF::NameSize);
OS << binary_le(i->Header.VirtualSize)
<< binary_le(i->Header.VirtualAddress)
<< binary_le(i->Header.SizeOfRawData)
<< binary_le(i->Header.PointerToRawData)
<< binary_le(i->Header.PointerToRelocations)
<< binary_le(i->Header.PointerToLineNumbers)
<< binary_le(i->Header.NumberOfRelocations)
<< binary_le(i->Header.NumberOfLineNumbers)
<< binary_le(i->Header.Characteristics);
}
unsigned CurSymbol = 0;
StringMap<unsigned> SymbolTableIndexMap;
for (std::vector<COFFYAML::Symbol>::iterator I = CP.Obj.Symbols.begin(),
E = CP.Obj.Symbols.end();
I != E; ++I) {
SymbolTableIndexMap[I->Name] = CurSymbol;
CurSymbol += 1 + I->Header.NumberOfAuxSymbols;
}
// Output section data.
for (std::vector<COFFYAML::Section>::iterator i = CP.Obj.Sections.begin(),
e = CP.Obj.Sections.end();
i != e; ++i) {
i->SectionData.writeAsBinary(OS);
for (unsigned I2 = 0, E2 = i->Relocations.size(); I2 != E2; ++I2) {
const COFFYAML::Relocation &R = i->Relocations[I2];
uint32_t SymbolTableIndex = SymbolTableIndexMap[R.SymbolName];
OS << binary_le(R.VirtualAddress)
<< binary_le(SymbolTableIndex)
<< binary_le(R.Type);
}
}
// Output symbol table.
for (std::vector<COFFYAML::Symbol>::const_iterator i = CP.Obj.Symbols.begin(),
e = CP.Obj.Symbols.end();
i != e; ++i) {
OS.write(i->Header.Name, COFF::NameSize);
OS << binary_le(i->Header.Value)
<< binary_le(i->Header.SectionNumber)
<< binary_le(i->Header.Type)
<< binary_le(i->Header.StorageClass)
<< binary_le(i->Header.NumberOfAuxSymbols);
if (i->FunctionDefinition)
OS << binary_le(i->FunctionDefinition->TagIndex)
<< binary_le(i->FunctionDefinition->TotalSize)
<< binary_le(i->FunctionDefinition->PointerToLinenumber)
<< binary_le(i->FunctionDefinition->PointerToNextFunction)
<< zeros(i->FunctionDefinition->unused);
if (i->bfAndefSymbol)
OS << zeros(i->bfAndefSymbol->unused1)
<< binary_le(i->bfAndefSymbol->Linenumber)
<< zeros(i->bfAndefSymbol->unused2)
<< binary_le(i->bfAndefSymbol->PointerToNextFunction)
<< zeros(i->bfAndefSymbol->unused3);
if (i->WeakExternal)
OS << binary_le(i->WeakExternal->TagIndex)
<< binary_le(i->WeakExternal->Characteristics)
<< zeros(i->WeakExternal->unused);
if (!i->File.empty()) {
uint32_t NumberOfAuxRecords =
(i->File.size() + COFF::SymbolSize - 1) / COFF::SymbolSize;
uint32_t NumberOfAuxBytes = NumberOfAuxRecords * COFF::SymbolSize;
uint32_t NumZeros = NumberOfAuxBytes - i->File.size();
OS.write(i->File.data(), i->File.size());
for (uint32_t Padding = 0; Padding < NumZeros; ++Padding)
OS.write(0);
}
if (i->SectionDefinition)
OS << binary_le(i->SectionDefinition->Length)
<< binary_le(i->SectionDefinition->NumberOfRelocations)
<< binary_le(i->SectionDefinition->NumberOfLinenumbers)
<< binary_le(i->SectionDefinition->CheckSum)
<< binary_le(i->SectionDefinition->Number)
<< binary_le(i->SectionDefinition->Selection)
<< zeros(i->SectionDefinition->unused);
if (i->CLRToken)
OS << binary_le(i->CLRToken->AuxType)
<< zeros(i->CLRToken->unused1)
<< binary_le(i->CLRToken->SymbolTableIndex)
<< zeros(i->CLRToken->unused2);
}
// Output string table.
OS.write(&CP.StringTable[0], CP.StringTable.size());
return true;
}
int yaml2coff(yaml::Input &YIn, raw_ostream &Out) {
COFFYAML::Object Doc;
YIn >> Doc;
if (YIn.error()) {
errs() << "yaml2obj: Failed to parse YAML file!\n";
return 1;
}
COFFParser CP(Doc);
if (!CP.parse()) {
errs() << "yaml2obj: Failed to parse YAML file!\n";
return 1;
}
if (!layoutCOFF(CP)) {
errs() << "yaml2obj: Failed to layout COFF file!\n";
return 1;
}
if (!writeCOFF(CP, Out)) {
errs() << "yaml2obj: Failed to write COFF file!\n";
return 1;
}
return 0;
}
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