path: root/lib/MC/WinCOFFObjectWriter.cpp

//===-- llvm/MC/WinCOFFObjectWriter.cpp -------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains an implementation of a Win32 COFF object file writer.
//
//===----------------------------------------------------------------------===//

#define DEBUG_TYPE "WinCOFFObjectWriter"

#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCValue.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCWinCOFFObjectWriter.h"

#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"

#include "llvm/Support/COFF.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"

#include "llvm/Support/TimeValue.h"

#include <cstdio>

using namespace llvm;

namespace {
typedef llvm::SmallString<COFF::NameSize> name;

enum AuxiliaryType {
  ATFunctionDefinition,
  ATbfAndefSymbol,
  ATWeakExternal,
  ATFile,
  ATSectionDefinition
};

struct AuxSymbol {
  AuxiliaryType   AuxType;
  COFF::Auxiliary Aux;
};

class COFFSymbol;
class COFFSection;

class COFFSymbol {
public:
  COFF::symbol Data;

  typedef llvm::SmallVector<AuxSymbol, 1> AuxiliarySymbols;

  name             Name;
  int              Index;
  AuxiliarySymbols Aux;
  COFFSymbol      *Other;
  COFFSection     *Section;
  int              Relocations;

  MCSymbolData const *MCData;

  COFFSymbol(llvm::StringRef name);
  size_t size() const;
  void set_name_offset(uint32_t Offset);

  bool should_keep() const;
};

// This class contains staging data for a COFF relocation entry.
struct COFFRelocation {
  COFF::relocation Data;
  COFFSymbol          *Symb;

  COFFRelocation() : Symb(NULL) {}
  static size_t size() { return COFF::RelocationSize; }
};

typedef std::vector<COFFRelocation> relocations;

class COFFSection {
public:
  COFF::section Header;

  std::string          Name;
  int                  Number;
  MCSectionData const *MCData;
  COFFSymbol          *Symbol;
  relocations          Relocations;

  COFFSection(llvm::StringRef name);
  static size_t size();
};

// This class holds the COFF string table.
class StringTable {
  typedef llvm::StringMap<size_t> map;
  map Map;

  void update_length();
public:
  std::vector<char> Data;

  StringTable();
  size_t size() const;
  size_t insert(llvm::StringRef String);
};

class WinCOFFObjectWriter : public MCObjectWriter {
public:

  typedef std::vector<COFFSymbol*>  symbols;
  typedef std::vector<COFFSection*> sections;

  typedef DenseMap<MCSymbol  const *, COFFSymbol *>   symbol_map;
  typedef DenseMap<MCSection const *, COFFSection *> section_map;

  llvm::OwningPtr<MCWinCOFFObjectTargetWriter> TargetObjectWriter;

  // Root level file contents.
  COFF::header Header;
  sections     Sections;
  symbols      Symbols;
  StringTable  Strings;

  // Maps used during object file creation.
  section_map SectionMap;
  symbol_map  SymbolMap;

  WinCOFFObjectWriter(MCWinCOFFObjectTargetWriter *MOTW, raw_ostream &OS);
  ~WinCOFFObjectWriter();

  COFFSymbol *createSymbol(StringRef Name);
  COFFSymbol *GetOrCreateCOFFSymbol(const MCSymbol * Symbol);
  COFFSection *createSection(StringRef Name);

  template <typename object_t, typename list_t>
  object_t *createCOFFEntity(llvm::StringRef Name, list_t &List);

  void DefineSection(MCSectionData const &SectionData);
  void DefineSymbol(MCSymbolData const &SymbolData, MCAssembler &Assembler);

  void MakeSymbolReal(COFFSymbol &S, size_t Index);
  void MakeSectionReal(COFFSection &S, size_t Number);

  bool ExportSection(COFFSection const *S);
  bool ExportSymbol(MCSymbolData const &SymbolData, MCAssembler &Asm);

  bool IsPhysicalSection(COFFSection *S);

  // Entity writing methods.

  void WriteFileHeader(const COFF::header &Header);
  void WriteSymbol(const COFFSymbol *S);
  void WriteAuxiliarySymbols(const COFFSymbol::AuxiliarySymbols &S);
  void WriteSectionHeader(const COFF::section &S);
  void WriteRelocation(const COFF::relocation &R);

  // MCObjectWriter interface implementation.

  void ExecutePostLayoutBinding(MCAssembler &Asm, const MCAsmLayout &Layout);

  void RecordRelocation(const MCAssembler &Asm,
                        const MCAsmLayout &Layout,
                        const MCFragment *Fragment,
                        const MCFixup &Fixup