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// reloc.h -- relocate input files for gold   -*- C++ -*-

// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.

// Written by Ian Lance Taylor <iant@google.com>.

// This file is part of gold.

// This program is free software; you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation; either version 3 of the License, or

// (at your option) any later version.

// This program is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License

// along with this program; if not, write to the Free Software

// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,

// MA 02110-1301, USA.

#ifndef GOLD_RELOC_H

#define GOLD_RELOC_H

#include <vector>

#include <byteswap.h>

#include "elfcpp.h"

#include "workqueue.h"

namespace gold

{

class General_options;

class Object;

class Relobj;

class Read_relocs_data;

class Symbol;

class Layout;

class Output_data;

class Output_section;

template<int size>

class Sized_symbol;

template<int size, bool big_endian>

class Sized_relobj;

template<int size>

class Symbol_value;

template<int sh_type, bool dynamic, int size, bool big_endian>

class Output_data_reloc;

// A class to read the relocations for an object file, and then queue

// up a task to see if they require any GOT/PLT/COPY relocations in

// the symbol table.

class Read_relocs : public Task

{

 public:

  // SYMTAB_LOCK is used to lock the symbol table.  BLOCKER should be

  // unblocked when the Scan_relocs task completes.

  Read_relocs(const General_options& options, Symbol_table* symtab,

              Layout* layout, Relobj* object, Task_token* symtab_lock,

              Task_token* blocker)

    : options_(options), symtab_(symtab), layout_(layout), object_(object),

      symtab_lock_(symtab_lock), blocker_(blocker)

  { }

  // The standard Task methods.

  Task_token*

  is_runnable();

  void

  locks(Task_locker*);

  void

  run(Workqueue*);

  std::string

  get_name() const;

 private:

  const General_options& options_;

  Symbol_table* symtab_;

  Layout* layout_;

  Relobj* object_;

  Task_token* symtab_lock_;

  Task_token* blocker_;

};

// Scan the relocations for an object to see if they require any

// GOT/PLT/COPY relocations.

class Scan_relocs : public Task

{

 public:

  // SYMTAB_LOCK is used to lock the symbol table.  BLOCKER should be

  // unblocked when the task completes.

  Scan_relocs(const General_options& options, Symbol_table* symtab,

              Layout* layout, Relobj* object, Read_relocs_data* rd,

              Task_token* symtab_lock, Task_token* blocker)

    : options_(options), symtab_(symtab), layout_(layout), object_(object),

      rd_(rd), symtab_lock_(symtab_lock), blocker_(blocker)

  { }

  // The standard Task methods.

  Task_token*

  is_runnable();

  void

  locks(Task_locker*);

  void

  run(Workqueue*);

  std::string

  get_name() const;

 private:

  const General_options& options_;

  Symbol_table* symtab_;

  Layout* layout_;

  Relobj* object_;

  Read_relocs_data* rd_;

  Task_token* symtab_lock_;

  Task_token* blocker_;

};

// A class to perform all the relocations for an object file.

class Relocate_task : public Task

{

 public:

  Relocate_task(const General_options& options, const Symbol_table* symtab,

                const Layout* layout, Relobj* object, Output_file* of,

                Task_token* input_sections_blocker,

                Task_token* output_sections_blocker, Task_token* final_blocker)

    : options_(options), symtab_(symtab), layout_(layout), object_(object),

      of_(of), input_sections_blocker_(input_sections_blocker),

      output_sections_blocker_(output_sections_blocker),

      final_blocker_(final_blocker)

  { }

  // The standard Task methods.

  Task_token*

  is_runnable();

  void

  locks(Task_locker*);

  void

  run(Workqueue*);

  std::string

  get_name() const;

 private:

  const General_options& options_;

  const Symbol_table* symtab_;

  const Layout* layout_;

  Relobj* object_;

  Output_file* of_;

  Task_token* input_sections_blocker_;

  Task_token* output_sections_blocker_;

  Task_token* final_blocker_;

};

// During a relocatable link, this class records how relocations

// should be handled for a single input reloc section.  An instance of

// this class is created while scanning relocs, and it is used while

// processing relocs.

class Relocatable_relocs

{

 public:

  // We use a vector of unsigned char to indicate how the input relocs

  // should be handled.  Each element is one of the following values.

  // We create this vector when we initially scan the relocations.

  enum Reloc_strategy

  {

    // Copy the input reloc.  Don't modify it other than updating the

    // r_offset field and the r_sym part of the r_info field.

    RELOC_COPY,

    // Copy the input reloc which is against an STT_SECTION symbol.

    // Update the r_offset and r_sym part of the r_info field.  Adjust

    // the addend by subtracting the value of the old local symbol and

    // adding the value of the new local symbol.  The addend is in the

    // SHT_RELA reloc and the contents of the data section do not need

    // to be changed.

    RELOC_ADJUST_FOR_SECTION_RELA,

    // Like RELOC_ADJUST_FOR_SECTION_RELA but the addend should not be

    // adjusted.

    RELOC_ADJUST_FOR_SECTION_0,

    // Like RELOC_ADJUST_FOR_SECTION_RELA but the contents of the

    // section need to be changed.  The number indicates the number of

    // bytes in the addend in the section contents.

    RELOC_ADJUST_FOR_SECTION_1,

    RELOC_ADJUST_FOR_SECTION_2,

    RELOC_ADJUST_FOR_SECTION_4,

    RELOC_ADJUST_FOR_SECTION_8,

    // Discard the input reloc--process it completely when relocating

    // the data section contents.

    RELOC_DISCARD,

    // An input reloc which is not discarded, but which requires

    // target specific processing in order to update it.

    RELOC_SPECIAL

  };

  Relocatable_relocs()

    : reloc_strategies_(), output_reloc_count_(0), posd_(NULL)

  { }

  // Record the number of relocs.

  void

  set_reloc_count(size_t reloc_count)

  { this->reloc_strategies_.reserve(reloc_count); }

  // Record what to do for the next reloc.

  void

  set_next_reloc_strategy(Reloc_strategy strategy)

  {

    this->reloc_strategies_.push_back(static_cast<unsigned char>(strategy));

    if (strategy != RELOC_DISCARD)

      ++this->output_reloc_count_;

  }

  // Record the Output_data associated with this reloc section.

  void

  set_output_data(Output_data* posd)

  {

    gold_assert(this->posd_ == NULL);

    this->posd_ = posd;

  }

  // Return the Output_data associated with this reloc section.

  Output_data*

  output_data() const

  { return this->posd_; }

  // Return what to do for reloc I.

  Reloc_strategy

  strategy(unsigned int i) const

  {

    gold_assert(i < this->reloc_strategies_.size());

    return static_cast<Reloc_strategy>(this->reloc_strategies_[i]);

  }

  // Return the number of relocations to create in the output file.

  size_t

  output_reloc_count() const

  { return this->output_reloc_count_; }

 private:

  typedef std::vector<unsigned char> Reloc_strategies;

  // The strategies for the input reloc.  There is one entry in this

  // vector for each relocation in the input section.

  Reloc_strategies reloc_strategies_;

  // The number of relocations to be created in the output file.

  size_t output_reloc_count_;

  // The output data structure associated with this relocation.

  Output_data* posd_;

};

// Standard relocation routines which are used on many targets.  Here

// SIZE and BIG_ENDIAN refer to the target, not the relocation type.

template<int size, bool big_endian>

class Relocate_functions

{

private:

  // Do a simple relocation with the addend in the section contents.

  // VALSIZE is the size of the value.

  template<int valsize>

  static inline void

  rel(unsigned char* view,

      typename elfcpp::Swap<valsize, big_endian>::Valtype value)

  {

    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;

    Valtype* wv = reinterpret_cast<Valtype*>(view);

    Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);

    elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value);

  }

  // Do a simple relocation using a Symbol_value with the addend in

  // the section contents.  VALSIZE is the size of the value to

  // relocate.

  template<int valsize>

  static inline void

  rel(unsigned char* view,

      const Sized_relobj<size, big_endian>* object,

      const Symbol_value<size>* psymval)

  {

    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;

    Valtype* wv = reinterpret_cast<Valtype*>(view);

    Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);

    x = psymval->value(object, x);

    elfcpp::Swap<valsize, big_endian>::writeval(wv, x);

  }

  // Do a simple relocation with the addend in the relocation.

  // VALSIZE is the size of the value.

  template<int valsize>

  static inline void

  rela(unsigned char* view,

       typename elfcpp::Swap<valsize, big_endian>::Valtype value,

       typename elfcpp::Swap<valsize, big_endian>::Valtype addend)

  {

    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;

    Valtype* wv = reinterpret_cast<Valtype*>(view);

    elfcpp::Swap<valsize, big_endian>::writeval(wv, value + addend);

  }

  // Do a simple relocation using a symbol value with the addend in

  // the relocation.  VALSIZE is the size of the value.

  template<int valsize>

  static inline void

  rela(unsigned char* view,

       const Sized_relobj<size, big_endian>* object,

       const Symbol_value<size>* psymval,

       typename elfcpp::Swap<valsize, big_endian>::Valtype addend)

  {

    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;

    Valtype* wv = reinterpret_cast<Valtype*>(view);

    Valtype x = psymval->value(object, addend);

    elfcpp::Swap<valsize, big_endian>::writeval(wv, x);

  }

  // Do a simple PC relative relocation with the addend in the section

  // contents.  VALSIZE is the size of the value.

  template<int valsize>

  static inline void

  pcrel(unsigned char* view,

        typename elfcpp::Swap<valsize, big_endian>::Valtype value,

        typename elfcpp::Elf_types<size>::Elf_Addr address)

  {

    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;

    Valtype* wv = reinterpret_cast<Valtype*>(view);

    Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);

    elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value - address);

  }

  // Do a simple PC relative relocation with a Symbol_value with the

  // addend in the section contents.  VALSIZE is the size of the

  // value.

  template<int valsize>

  static inline void

  pcrel(unsigned char* view,

        const Sized_relobj<size, big_endian>* object,

        const Symbol_value<size>* psymval,

        typename elfcpp::Elf_types<size>::Elf_Addr address)

  {

    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;

    Valtype* wv = reinterpret_cast<Valtype*>(view);

    Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);

    x = psymval->value(object, x);

    elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address);

  }

  // Do a simple PC relative relocation with the addend in the

  // relocation.  VALSIZE is the size of the value.

  template<int valsize>

  static inline void

  pcrela(unsigned char* view,

         typename elfcpp::Swap<valsize, big_endian>::Valtype value,

         typename elfcpp::Swap<valsize, big_endian>::Valtype addend,

         typename elfcpp::Elf_types<size>::Elf_Addr address)

  {

    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;

    Valtype* wv = reinterpret_cast<Valtype*>(view);

    elfcpp::Swap<valsize, big_endian>::writeval(wv, value + addend - address);

  }

  // Do a simple PC relative relocation with a Symbol_value with the

  // addend in the relocation.  VALSIZE is the size of the value.

  template<int valsize>

  static inline void

  pcrela(unsigned char* view,

         const Sized_relobj<size, big_endian>* object,

         const Symbol_value<size>* psymval,

         typename elfcpp::Swap<valsize, big_endian>::Valtype addend,

         typename elfcpp::Elf_types<size>::Elf_Addr address)

  {

    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;

    Valtype* wv = reinterpret_cast<Valtype*>(view);

    Valtype x = psymval->value(object, addend);

    elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address);

  }

  typedef Relocate_functions<size, big_endian> This;

public:

  // Do a simple 8-bit REL relocation with the addend in the section

  // contents.

  static inline void

  rel8(unsigned char* view, unsigned char value)

  { This::template rel<8>(view, value); }

  static inline void

  rel8(unsigned char* view,

       const Sized_relobj<size, big_endian>* object,

       const Symbol_value<size>* psymval)

  { This::template rel<8>(view, object, psymval); }

  // Do an 8-bit RELA relocation with the addend in the relocation.

  static inline void

  rela8(unsigned char* view, unsigned char value, unsigned char addend)

  { This::template rela<8>(view, value, addend); }

  static inline void

  rela8(unsigned char* view,

        const Sized_relobj<size, big_endian>* object,

        const Symbol_value<size>* psymval,

        unsigned char addend)

  { This::template rela<8>(view, object, psymval, addend); }

  // Do a simple 8-bit PC relative relocation with the addend in the

  // section contents.

  static inline void

  pcrel8(unsigned char* view, unsigned char value,

         typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrel<8>(view, value, address); }

  static inline void

  pcrel8(unsigned char* view,

         const Sized_relobj<size, big_endian>* object,

         const Symbol_value<size>* psymval,

         typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrel<8>(view, object, psymval, address); }

  // Do a simple 8-bit PC relative RELA relocation with the addend in

  // the reloc.

  static inline void

  pcrela8(unsigned char* view, unsigned char value, unsigned char addend,

          typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrela<8>(view, value, addend, address); }

  static inline void

  pcrela8(unsigned char* view,

          const Sized_relobj<size, big_endian>* object,

          const Symbol_value<size>* psymval,

          unsigned char addend,

          typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrela<8>(view, object, psymval, addend, address); }

  // Do a simple 16-bit REL relocation with the addend in the section

  // contents.

  static inline void

  rel16(unsigned char* view, elfcpp::Elf_Half value)

  { This::template rel<16>(view, value); }

  static inline void

  rel16(unsigned char* view,

        const Sized_relobj<size, big_endian>* object,

        const Symbol_value<size>* psymval)

  { This::template rel<16>(view, object, psymval); }

  // Do an 16-bit RELA relocation with the addend in the relocation.

  static inline void

  rela16(unsigned char* view, elfcpp::Elf_Half value, elfcpp::Elf_Half addend)

  { This::template rela<16>(view, value, addend); }

  static inline void

  rela16(unsigned char* view,

         const Sized_relobj<size, big_endian>* object,

         const Symbol_value<size>* psymval,

         elfcpp::Elf_Half addend)

  { This::template rela<16>(view, object, psymval, addend); }

  // Do a simple 16-bit PC relative REL relocation with the addend in

  // the section contents.

  static inline void

  pcrel16(unsigned char* view, elfcpp::Elf_Half value,

          typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrel<16>(view, value, address); }

  static inline void

  pcrel16(unsigned char* view,

          const Sized_relobj<size, big_endian>* object,

          const Symbol_value<size>* psymval,

          typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrel<16>(view, object, psymval, address); }

  // Do a simple 16-bit PC relative RELA relocation with the addend in

  // the reloc.

  static inline void

  pcrela16(unsigned char* view, elfcpp::Elf_Half value,

           elfcpp::Elf_Half addend,

           typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrela<16>(view, value, addend, address); }

  static inline void

  pcrela16(unsigned char* view,

           const Sized_relobj<size, big_endian>* object,

           const Symbol_value<size>* psymval,

           elfcpp::Elf_Half addend,

           typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrela<16>(view, object, psymval, addend, address); }

  // Do a simple 32-bit REL relocation with the addend in the section

  // contents.

  static inline void

  rel32(unsigned char* view, elfcpp::Elf_Word value)

  { This::template rel<32>(view, value); }

  static inline void

  rel32(unsigned char* view,

        const Sized_relobj<size, big_endian>* object,

        const Symbol_value<size>* psymval)

  { This::template rel<32>(view, object, psymval); }

  // Do an 32-bit RELA relocation with the addend in the relocation.

  static inline void

  rela32(unsigned char* view, elfcpp::Elf_Word value, elfcpp::Elf_Word addend)

  { This::template rela<32>(view, value, addend); }

  static inline void

  rela32(unsigned char* view,

         const Sized_relobj<size, big_endian>* object,

         const Symbol_value<size>* psymval,

         elfcpp::Elf_Word addend)

  { This::template rela<32>(view, object, psymval, addend); }

  // Do a simple 32-bit PC relative REL relocation with the addend in

  // the section contents.

  static inline void

  pcrel32(unsigned char* view, elfcpp::Elf_Word value,

          typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrel<32>(view, value, address); }

  static inline void

  pcrel32(unsigned char* view,

          const Sized_relobj<size, big_endian>* object,

          const Symbol_value<size>* psymval,

          typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrel<32>(view, object, psymval, address); }

  // Do a simple 32-bit PC relative RELA relocation with the addend in

  // the relocation.

  static inline void

  pcrela32(unsigned char* view, elfcpp::Elf_Word value,

           elfcpp::Elf_Word addend,

           typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrela<32>(view, value, addend, address); }

  static inline void

  pcrela32(unsigned char* view,

           const Sized_relobj<size, big_endian>* object,

           const Symbol_value<size>* psymval,

           elfcpp::Elf_Word addend,

           typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrela<32>(view, object, psymval, addend, address); }

  // Do a simple 64-bit REL relocation with the addend in the section

  // contents.

  static inline void

  rel64(unsigned char* view, elfcpp::Elf_Xword value)

  { This::template rel<64>(view, value); }

  static inline void

  rel64(unsigned char* view,

        const Sized_relobj<size, big_endian>* object,

        const Symbol_value<size>* psymval)

  { This::template rel<64>(view, object, psymval); }

  // Do a 64-bit RELA relocation with the addend in the relocation.

  static inline void

  rela64(unsigned char* view, elfcpp::Elf_Xword value,

         elfcpp::Elf_Xword addend)

  { This::template rela<64>(view, value, addend); }

  static inline void

  rela64(unsigned char* view,

         const Sized_relobj<size, big_endian>* object,

         const Symbol_value<size>* psymval,

         elfcpp::Elf_Xword addend)

  { This::template rela<64>(view, object, psymval, addend); }

  // Do a simple 64-bit PC relative REL relocation with the addend in

  // the section contents.

  static inline void

  pcrel64(unsigned char* view, elfcpp::Elf_Xword value,

          typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrel<64>(view, value, address); }

  static inline void

  pcrel64(unsigned char* view,

          const Sized_relobj<size, big_endian>* object,

          const Symbol_value<size>* psymval,

          typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrel<64>(view, object, psymval, address); }

  // Do a simple 64-bit PC relative RELA relocation with the addend in

  // the relocation.

  static inline void

  pcrela64(unsigned char* view, elfcpp::Elf_Xword value,

           elfcpp::Elf_Xword addend,

           typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrela<64>(view, value, addend, address); }

  static inline void

  pcrela64(unsigned char* view,

           const Sized_relobj<size, big_endian>* object,

           const Symbol_value<size>* psymval,

           elfcpp::Elf_Xword addend,

           typename elfcpp::Elf_types<size>::Elf_Addr address)

  { This::template pcrela<64>(view, object, psymval, addend, address); }

};

// Track relocations while reading a section.  This lets you ask for

// the relocation at a certain offset, and see how relocs occur

// between points of interest.

template<int size, bool big_endian>

class Track_relocs

{

 public:

  Track_relocs()

    : prelocs_(NULL), len_(0), pos_(0), reloc_size_(0)

  { }

  // Initialize the Track_relocs object.  OBJECT is the object holding

  // the reloc section, RELOC_SHNDX is the section index of the reloc

  // section, and RELOC_TYPE is the type of the reloc section

  // (elfcpp::SHT_REL or elfcpp::SHT_RELA).  This returns false if

  // something went wrong.

  bool

  initialize(Object* object, unsigned int reloc_shndx,

             unsigned int reloc_type);

  // Return the offset in the data section to which the next reloc

  // applies.  THis returns -1 if there is no next reloc.

  off_t

  next_offset() const;

  // Return the symbol index of the next reloc.  This returns -1U if

  // there is no next reloc.

  unsigned int

  next_symndx() const;