[deliverable/binutils-gdb.git] / gold / powerpc.cc

// powerpc.cc -- powerpc target support for gold.

// Copyright 2008, 2009 Free Software Foundation, Inc.
// Written by David S. Miller <davem@davemloft.net>
//        and David Edelsohn <edelsohn@gnu.org>

// 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.

#include "gold.h"

#include "elfcpp.h"
#include "parameters.h"
#include "reloc.h"
#include "powerpc.h"
#include "object.h"
#include "symtab.h"
#include "layout.h"
#include "output.h"
#include "copy-relocs.h"
#include "target.h"
#include "target-reloc.h"
#include "target-select.h"
#include "tls.h"
#include "errors.h"
#include "gc.h"

namespace
{

using namespace gold;

template<int size, bool big_endian>
class Output_data_plt_powerpc;

template<int size, bool big_endian>
class Target_powerpc : public Sized_target<size, big_endian>
{
 public:
  typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, big_endian> Reloc_section;

  Target_powerpc()
    : Sized_target<size, big_endian>(&powerpc_info),
      got_(NULL), got2_(NULL), toc_(NULL),
      plt_(NULL), rela_dyn_(NULL),
      copy_relocs_(elfcpp::R_POWERPC_COPY),
      dynbss_(NULL), got_mod_index_offset_(-1U)
  {
  }

  // Process the relocations to determine unreferenced sections for 
  // garbage collection.
  void
  gc_process_relocs(Symbol_table* symtab,
                    Layout* layout,
                    Sized_relobj<size, big_endian>* object,
                    unsigned int data_shndx,
                    unsigned int sh_type,
                    const unsigned char* prelocs,
                    size_t reloc_count,
                    Output_section* output_section,
                    bool needs_special_offset_handling,
                    size_t local_symbol_count,
                    const unsigned char* plocal_symbols);

  // Scan the relocations to look for symbol adjustments.
  void
  scan_relocs(Symbol_table* symtab,
              Layout* layout,
              Sized_relobj<size, big_endian>* object,
              unsigned int data_shndx,
              unsigned int sh_type,
              const unsigned char* prelocs,
              size_t reloc_count,
              Output_section* output_section,
              bool needs_special_offset_handling,
              size_t local_symbol_count,
              const unsigned char* plocal_symbols);
  // Finalize the sections.
  void
  do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);

  // Return the value to use for a dynamic which requires special
  // treatment.
  uint64_t
  do_dynsym_value(const Symbol*) const;

  // Relocate a section.
  void
  relocate_section(const Relocate_info<size, big_endian>*,
                   unsigned int sh_type,
                   const unsigned char* prelocs,
                   size_t reloc_count,
                   Output_section* output_section,
                   bool needs_special_offset_handling,
                   unsigned char* view,
                   typename elfcpp::Elf_types<size>::Elf_Addr view_address,
                   section_size_type view_size,
                   const Reloc_symbol_changes*);

  // Scan the relocs during a relocatable link.
  void
  scan_relocatable_relocs(Symbol_table* symtab,
                          Layout* layout,
                          Sized_relobj<size, big_endian>* object,
                          unsigned int data_shndx,
                          unsigned int sh_type,
                          const unsigned char* prelocs,
                          size_t reloc_count,
                          Output_section* output_section,
                          bool needs_special_offset_handling,
                          size_t local_symbol_count,
                          const unsigned char* plocal_symbols,
                          Relocatable_relocs*);

  // Relocate a section during a relocatable link.
  void
  relocate_for_relocatable(const Relocate_info<size, big_endian>*,
                           unsigned int sh_type,
                           const unsigned char* prelocs,
                           size_t reloc_count,
                           Output_section* output_section,
                           off_t offset_in_output_section,
                           const Relocatable_relocs*,
                           unsigned char* view,
                           typename elfcpp::Elf_types<size>::Elf_Addr view_address,
                           section_size_type view_size,
                           unsigned char* reloc_view,
                           section_size_type reloc_view_size);

  // Return whether SYM is defined by the ABI.
  bool
  do_is_defined_by_abi(const Symbol* sym) const
  {
    return strcmp(sym->name(), "___tls_get_addr") == 0;
  }

  // Return the size of the GOT section.
  section_size_type
  got_size()
  {
    gold_assert(this->got_ != NULL);
    return this->got_->data_size();
  }

 private:

  // The class which scans relocations.
  class Scan
  {
  public:
    Scan()
      : issued_non_pic_error_(false)
    { }

    inline void
    local(Symbol_table* symtab, Layout* layout, Target_powerpc* target,
          Sized_relobj<size, big_endian>* object,
          unsigned int data_shndx,
          Output_section* output_section,
          const elfcpp::Rela<size, big_endian>& reloc, unsigned int r_type,
          const elfcpp::Sym<size, big_endian>& lsym);

    inline void
    global(Symbol_table* symtab, Layout* layout, Target_powerpc* target,
           Sized_relobj<size, big_endian>* object,
           unsigned int data_shndx,
           Output_section* output_section,
           const elfcpp::Rela<size, big_endian>& reloc, unsigned int r_type,
           Symbol* gsym);

  private:
    static void
    unsupported_reloc_local(Sized_relobj<size, big_endian>*,
                            unsigned int r_type);

    static void
    unsupported_reloc_global(Sized_relobj<size, big_endian>*,
                             unsigned int r_type, Symbol*);

    static void
    generate_tls_call(Symbol_table* symtab, Layout* layout,
                      Target_powerpc* target);

    void
    check_non_pic(Relobj*, unsigned int r_type);

    // Whether we have issued an error about a non-PIC compilation.
    bool issued_non_pic_error_;
  };

  // The class which implements relocation.
  class Relocate
  {
   public:
    // Do a relocation.  Return false if the caller should not issue
    // any warnings about this relocation.
    inline bool
    relocate(const Relocate_info<size, big_endian>*, Target_powerpc*,
             Output_section*, size_t relnum,
             const elfcpp::Rela<size, big_endian>&,
             unsigned int r_type, const Sized_symbol<size>*,
             const Symbol_value<size>*,
             unsigned char*,
             typename elfcpp::Elf_types<size>::Elf_Addr,
             section_size_type);

   private:
    // Do a TLS relocation.
    inline void
    relocate_tls(const Relocate_info<size, big_endian>*,
                 Target_powerpc* target,
                 size_t relnum, const elfcpp::Rela<size, big_endian>&,
                 unsigned int r_type, const Sized_symbol<size>*,
                 const Symbol_value<size>*,
                 unsigned char*,
                 typename elfcpp::Elf_types<size>::Elf_Addr,
                 section_size_type);
  };

  // A class which returns the size required for a relocation type,
  // used while scanning relocs during a relocatable link.
  class Relocatable_size_for_reloc
  {
   public:
    unsigned int
    get_size_for_reloc(unsigned int, Relobj*);
  };

  // Get the GOT section, creating it if necessary.
  Output_data_got<size, big_endian>*
  got_section(Symbol_table*, Layout*);

  Output_data_space*
  got2_section() const
  {
    gold_assert (this->got2_ != NULL);
    return this->got2_;
  }

  // Get the TOC section.
  Output_data_space*
  toc_section() const
  {
    gold_assert (this->toc_ != NULL);
    return this->toc_;
  }

  // Create a PLT entry for a global symbol.
  void
  make_plt_entry(Symbol_table*, Layout*, Symbol*);

  // Create a GOT entry for the TLS module index.
  unsigned int
  got_mod_index_entry(Symbol_table* symtab, Layout* layout,
                      Sized_relobj<size, big_endian>* object);

  // Get the PLT section.
  const Output_data_plt_powerpc<size, big_endian>*
  plt_section() const
  {
    gold_assert(this->plt_ != NULL);
    return this->plt_;
  }

  // Get the dynamic reloc section, creating it if necessary.
  Reloc_section*
  rela_dyn_section(Layout*);

  // Copy a relocation against a global symbol.
  void
  copy_reloc(Symbol_table* symtab, Layout* layout,
             Sized_relobj<size, big_endian>* object,
             unsigned int shndx, Output_section* output_section,
             Symbol* sym, const elfcpp::Rela<size, big_endian>& reloc)
  {
    this->copy_relocs_.copy_reloc(symtab, layout,
                                  symtab->get_sized_symbol<size>(sym),
                                  object, shndx, output_section,
                                  reloc, this->rela_dyn_section(layout));
  }

  // Information about this specific target which we pass to the
  // general Target structure.
  static Target::Target_info powerpc_info;

  // The types of GOT entries needed for this platform.
  enum Got_type
  {
    GOT_TYPE_STANDARD = 0,      // GOT entry for a regular symbol
    GOT_TYPE_TLS_OFFSET = 1,    // GOT entry for TLS offset
    GOT_TYPE_TLS_PAIR = 2,      // GOT entry for TLS module/offset pair
  };

  // The GOT section.
  Output_data_got<size, big_endian>* got_;
  // The GOT2 section.
  Output_data_space* got2_;
  // The TOC section.
  Output_data_space* toc_;
  // The PLT section.
  Output_data_plt_powerpc<size, big_endian>* plt_;
  // The dynamic reloc section.
  Reloc_section* rela_dyn_;
  // Relocs saved to avoid a COPY reloc.
  Copy_relocs<elfcpp::SHT_RELA, size, big_endian> copy_relocs_;
  // Space for variables copied with a COPY reloc.
  Output_data_space* dynbss_;
  // Offset of the GOT entry for the TLS module index;
  unsigned int got_mod_index_offset_;
};

template<>
Target::Target_info Target_powerpc<32, true>::powerpc_info =
{
  32,                   // size
  true,                 // is_big_endian
  elfcpp::EM_PPC,       // machine_code
  false,                // has_make_symbol
  false,                // has_resolve
  false,                // has_code_fill
  true,                 // is_default_stack_executable
  '\0',                 // wrap_char
  "/usr/lib/ld.so.1",   // dynamic_linker
  0x10000000,           // default_text_segment_address
  64 * 1024,            // abi_pagesize (overridable by -z max-page-size)
  4 * 1024,             // common_pagesize (overridable by -z common-page-size)
  elfcpp::SHN_UNDEF,    // small_common_shndx
  elfcpp::SHN_UNDEF,    // large_common_shndx
  0,                    // small_common_section_flags
  0,                    // large_common_section_flags
  NULL,                 // attributes_section
  NULL                  // attributes_vendor
};

template<>
Target::Target_info Target_powerpc<32, false>::powerpc_info =
{
  32,                   // size
  false,                // is_big_endian
  elfcpp::EM_PPC,       // machine_code
  false,                // has_make_symbol
  false,                // has_resolve
  false,                // has_code_fill
  true,                 // is_default_stack_executable
  '\0',                 // wrap_char
  "/usr/lib/ld.so.1",   // dynamic_linker
  0x10000000,           // default_text_segment_address
  64 * 1024,            // abi_pagesize (overridable by -z max-page-size)
  4 * 1024,             // common_pagesize (overridable by -z common-page-size)
  elfcpp::SHN_UNDEF,    // small_common_shndx
  elfcpp::SHN_UNDEF,    // large_common_shndx
  0,                    // small_common_section_flags
  0,                    // large_common_section_flags
  NULL,                 // attributes_section
  NULL                  // attributes_vendor
};

template<>
Target::Target_info Target_powerpc<64, true>::powerpc_info =
{
  64,                   // size
  true,                 // is_big_endian
  elfcpp::EM_PPC64,     // machine_code
  false,                // has_make_symbol
  false,                // has_resolve
  false,                // has_code_fill
  true,                 // is_default_stack_executable
  '\0',                 // wrap_char
  "/usr/lib/ld.so.1",   // dynamic_linker
  0x10000000,           // default_text_segment_address
  64 * 1024,            // abi_pagesize (overridable by -z max-page-size)
  8 * 1024,             // common_pagesize (overridable by -z common-page-size)
  elfcpp::SHN_UNDEF,    // small_common_shndx
  elfcpp::SHN_UNDEF,    // large_common_shndx
  0,                    // small_common_section_flags
  0,                    // large_common_section_flags
  NULL,                 // attributes_section
  NULL                  // attributes_vendor
};

template<>
Target::Target_info Target_powerpc<64, false>::powerpc_info =
{
  64,                   // size
  false,                // is_big_endian
  elfcpp::EM_PPC64,     // machine_code
  false,                // has_make_symbol
  false,                // has_resolve
  false,                // has_code_fill
  true,                 // is_default_stack_executable
  '\0',                 // wrap_char
  "/usr/lib/ld.so.1",   // dynamic_linker
  0x10000000,           // default_text_segment_address
  64 * 1024,            // abi_pagesize (overridable by -z max-page-size)
  8 * 1024,             // common_pagesize (overridable by -z common-page-size)
  elfcpp::SHN_UNDEF,    // small_common_shndx
  elfcpp::SHN_UNDEF,    // large_common_shndx
  0,                    // small_common_section_flags
  0,                    // large_common_section_flags
  NULL,                 // attributes_section
  NULL                  // attributes_vendor
};

template<int size, bool big_endian>
class Powerpc_relocate_functions
{
private:
  // Do a simple relocation with the addend in the relocation.
  template<int valsize>
  static inline void
  rela(unsigned char* view,
       unsigned int right_shift,
       elfcpp::Elf_Xword dst_mask,
       typename elfcpp::Swap<size, big_endian>::Valtype value,
       typename elfcpp::Swap<size, big_endian>::Valtype addend)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    Valtype val = elfcpp::Swap<valsize, big_endian>::readval(wv);
    Valtype reloc = ((value + addend) >> right_shift);

    val &= ~dst_mask;
    reloc &= dst_mask;

    elfcpp::Swap<valsize, big_endian>::writeval(wv, val | reloc);
  }

  // Do a simple relocation using a symbol value with the addend in
  // the relocation.
  template<int valsize>
  static inline void
  rela(unsigned char* view,
       unsigned int right_shift,
       elfcpp::Elf_Xword dst_mask,
       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 val = elfcpp::Swap<valsize, big_endian>::readval(wv);
    Valtype reloc = (psymval->value(object, addend) >> right_shift);

    val &= ~dst_mask;
    reloc &= dst_mask;

    elfcpp::Swap<valsize, big_endian>::writeval(wv, val | reloc);
  }

  // Do a simple relocation using a symbol value with the addend in
  // the relocation, unaligned.
  template<int valsize>
  static inline void
  rela_ua(unsigned char* view, unsigned int right_shift,
          elfcpp::Elf_Xword dst_mask,
          const Sized_relobj<size, big_endian>* object,
          const Symbol_value<size>* psymval,
          typename elfcpp::Swap<size, big_endian>::Valtype addend)
  {
    typedef typename elfcpp::Swap_unaligned<valsize,
            big_endian>::Valtype Valtype;
    unsigned char* wv = view;
    Valtype val = elfcpp::Swap_unaligned<valsize, big_endian>::readval(wv);
    Valtype reloc = (psymval->value(object, addend) >> right_shift);

    val &= ~dst_mask;
    reloc &= dst_mask;

    elfcpp::Swap_unaligned<valsize, big_endian>::writeval(wv, val | reloc);
  }

  // Do a simple PC relative relocation with a Symbol_value with the
  // addend in the relocation.
  template<int valsize>
  static inline void
  pcrela(unsigned char* view, unsigned int right_shift,
         elfcpp::Elf_Xword dst_mask,
         const Sized_relobj<size, big_endian>* object,
         const Symbol_value<size>* psymval,
         typename elfcpp::Swap<size, 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 val = elfcpp::Swap<valsize, big_endian>::readval(wv);
    Valtype reloc = ((psymval->value(object, addend) - address)
                     >> right_shift);

    val &= ~dst_mask;
    reloc &= dst_mask;

    elfcpp::Swap<valsize, big_endian>::writeval(wv, val | reloc);
  }

  template<int valsize>
  static inline void
  pcrela_unaligned(unsigned char* view,
                   const Sized_relobj<size, big_endian>* object,
                   const Symbol_value<size>* psymval,
                   typename elfcpp::Swap<size, big_endian>::Valtype addend,
                   typename elfcpp::Elf_types<size>::Elf_Addr address)
  {
    typedef typename elfcpp::Swap_unaligned<valsize,
            big_endian>::Valtype Valtype;
    unsigned char* wv = view;
    Valtype reloc = (psymval->value(object, addend) - address);

    elfcpp::Swap_unaligned<valsize, big_endian>::writeval(wv, reloc);
  }

  typedef Powerpc_relocate_functions<size, big_endian> This;
  typedef Relocate_functions<size, big_endian> This_reloc;
public:
  // R_POWERPC_REL32: (Symbol + Addend - Address)
  static inline void
  rel32(unsigned char* view,
        const Sized_relobj<size, big_endian>* object,
        const Symbol_value<size>* psymval,
        typename elfcpp::Elf_types<size>::Elf_Addr addend,
        typename elfcpp::Elf_types<size>::Elf_Addr address)
  { This_reloc::pcrela32(view, object, psymval, addend, address); }

  // R_POWERPC_REL24: (Symbol + Addend - Address) & 0x3fffffc
  static inline void
  rel24(unsigned char* view,
        const Sized_relobj<size, big_endian>* object,
        const Symbol_value<size>* psymval,
        typename elfcpp::Elf_types<size>::Elf_Addr addend,
        typename elfcpp::Elf_types<size>::Elf_Addr address)
  {
    This::template pcrela<32>(view, 0, 0x03fffffc, object,
                              psymval, addend, address);
  }

  // R_POWERPC_REL14: (Symbol + Addend - Address) & 0xfffc
  static inline void
  rel14(unsigned char* view,
        const Sized_relobj<size, big_endian>* object,
        const Symbol_value<size>* psymval,
        typename elfcpp::Elf_types<size>::Elf_Addr addend,
        typename elfcpp::Elf_types<size>::Elf_Addr address)
  {
    This::template pcrela<32>(view, 0, 0x0000fffc, object,
                              psymval, addend, address);
  }

  // R_POWERPC_ADDR16: (Symbol + Addend) & 0xffff
  static inline void
  addr16(unsigned char* view,
         typename elfcpp::Elf_types<size>::Elf_Addr value,
         typename elfcpp::Elf_types<size>::Elf_Addr addend)
  { This_reloc::rela16(view, value, addend); }

  static inline void
  addr16(unsigned char* view,
         const Sized_relobj<size, big_endian>* object,
         const Symbol_value<size>* psymval,
         typename elfcpp::Elf_types<size>::Elf_Addr addend)
  { This_reloc::rela16(view, object, psymval, addend); }

  // R_POWERPC_ADDR16_DS: (Symbol + Addend) & 0xfffc
  static inline void
  addr16_ds(unsigned char* view,
            typename elfcpp::Elf_types<size>::Elf_Addr value,
            typename elfcpp::Elf_types<size>::Elf_Addr addend)
  {
    This::template rela<16>(view, 0, 0xfffc, value, addend);
  }

  // R_POWERPC_ADDR16_LO: (Symbol + Addend) & 0xffff
  static inline void
  addr16_lo(unsigned char* view,
         typename elfcpp::Elf_types<size>::Elf_Addr value,
         typename elfcpp::Elf_types<size>::Elf_Addr addend)
  { This_reloc::rela16(view, value, addend); }

  static inline void
  addr16_lo(unsigned char* view,
            const Sized_relobj<size, big_endian>* object,
            const Symbol_value<size>* psymval,
            typename elfcpp::Elf_types<size>::Elf_Addr addend)
  { This_reloc::rela16(view, object, psymval, addend); }

  // R_POWERPC_ADDR16_HI: ((Symbol + Addend) >> 16) & 0xffff
  static inline void
  addr16_hi(unsigned char* view,
            typename elfcpp::Elf_types<size>::Elf_Addr value,
            typename elfcpp::Elf_types<size>::Elf_Addr addend)
  {
    This::template rela<16>(view, 16, 0xffff, value, addend);
  }

  static inline void
  addr16_hi(unsigned char* view,
            const Sized_relobj<size, big_endian>* object,
            const Symbol_value<size>* psymval,
            typename elfcpp::Elf_types<size>::Elf_Addr addend)
  {
    This::template rela<16>(view, 16, 0xffff, object, psymval, addend);
  }

  // R_POWERPC_ADDR16_HA: Same as R_POWERPC_ADDR16_HI except that if the
  //                      final value of the low 16 bits of the
  //                      relocation is negative, add one.
  static inline void
  addr16_ha(unsigned char* view,
            typename elfcpp::Elf_types<size>::Elf_Addr value,
            typename elfcpp::Elf_types<size>::Elf_Addr addend)
  {
    typename elfcpp::Elf_types<size>::Elf_Addr reloc;

    reloc = value + addend;

    if (reloc & 0x8000)
      reloc += 0x10000;
    reloc >>= 16;

    elfcpp::Swap<16, big_endian>::writeval(view, reloc);
  }

  static inline void
  addr16_ha(unsigned char* view,
            const Sized_relobj<size, big_endian>* object,
            const Symbol_value<size>* psymval,
            typename elfcpp::Elf_types<size>::Elf_Addr addend)
  {
    typename elfcpp::Elf_types<size>::Elf_Addr reloc;

    reloc = psymval->value(object, addend);

    if (reloc & 0x8000)
      reloc += 0x10000;
    reloc >>= 16;

    elfcpp::Swap<16, big_endian>::writeval(view, reloc);
  }

  // R_PPC_REL16: (Symbol + Addend - Address) & 0xffff
  static inline void
  rel16(unsigned char* view,
        const Sized_relobj<size, big_endian>* object,
        const Symbol_value<size>* psymval,
        typename elfcpp::Elf_types<size>::Elf_Addr addend,
        typename elfcpp::Elf_types<size>::Elf_Addr address)
  { This_reloc::pcrela16(view, object, psymval, addend, address); }

  // R_PPC_REL16_LO: (Symbol + Addend - Address) & 0xffff
  static inline void
  rel16_lo(unsigned char* view,
           const Sized_relobj<size, big_endian>* object,
           const Symbol_value<size>* psymval,
           typename elfcpp::Elf_types<size>::Elf_Addr addend,
           typename elfcpp::Elf_types<size>::Elf_Addr address)
  { This_reloc::pcrela16(view, object, psymval, addend, address); }

  // R_PPC_REL16_HI: ((Symbol + Addend - Address) >> 16) & 0xffff
  static inline void
  rel16_hi(unsigned char* view,
           const Sized_relobj<size, big_endian>* object,
           const Symbol_value<size>* psymval,
           typename elfcpp::Elf_types<size>::Elf_Addr addend,
           typename elfcpp::Elf_types<size>::Elf_Addr address)
  {
    This::template pcrela<16>(view, 16, 0xffff, object,
                              psymval, addend, address);
  }

  // R_PPC_REL16_HA: Same as R_PPC_REL16_HI except that if the
  //                 final value of the low 16 bits of the
  //                 relocation is negative, add one.
  static inline void
  rel16_ha(unsigned char* view,
           const Sized_relobj<size, big_endian>* object,
           const Symbol_value<size>* psymval,
           typename elfcpp::Elf_types<size>::Elf_Addr addend,
           typename elfcpp::Elf_types<size>::Elf_Addr address)
  {
    typename elfcpp::Elf_types<size>::Elf_Addr reloc;

    reloc = (psymval->value(object, addend) - address);
    if (reloc & 0x8000)
      reloc += 0x10000;
    reloc >>= 16;

    elfcpp::Swap<16, big_endian>::writeval(view, reloc);
  }
};

// Get the GOT section, creating it if necessary.

template<int size, bool big_endian>
Output_data_got<size, big_endian>*
Target_powerpc<size, big_endian>::got_section(Symbol_table* symtab,
                                              Layout* layout)
{
  if (this->got_ == NULL)
    {
      gold_assert(symtab != NULL && layout != NULL);

      this->got_ = new Output_data_got<size, big_endian>();

      layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
                                      elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
                                      this->got_, false);

      // Create the GOT2 or TOC in the .got section.
      if (size == 32)
        {
          this->got2_ = new Output_data_space(4, "** GOT2");
          layout->add_output_section_data(".got2", elfcpp::SHT_PROGBITS,
                                          elfcpp::SHF_ALLOC
                                          | elfcpp::SHF_WRITE,
                                          this->got2_, false);
        }
      else
        {
          this->toc_ = new Output_data_space(8, "** TOC");
          layout->add_output_section_data(".toc", elfcpp::SHT_PROGBITS,
                                          elfcpp::SHF_ALLOC
                                          | elfcpp::SHF_WRITE,
                                          this->toc_, false);
        }

      // Define _GLOBAL_OFFSET_TABLE_ at the start of the .got section.
      symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
                                    Symbol_table::PREDEFINED,
                                    this->got_,
                                    0, 0, elfcpp::STT_OBJECT,
                                    elfcpp::STB_LOCAL,
                                    elfcpp::STV_HIDDEN, 0,
                                    false, false);
    }

  return this->got_;
}

// Get the dynamic reloc section, creating it if necessary.

template<int size, bool big_endian>
typename Target_powerpc<size, big_endian>::Reloc_section*
Target_powerpc<size, big_endian>::rela_dyn_section(Layout* layout)
{
  if (this->rela_dyn_ == NULL)
    {
      gold_assert(layout != NULL);
      this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
      layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
                                      elfcpp::SHF_ALLOC, this->rela_dyn_, true);
    }
  return this->rela_dyn_;
}

// A class to handle the PLT data.

template<int size, bool big_endian>
class Output_data_plt_powerpc : public Output_section_data
{
 public:
  typedef Output_data_reloc<elfcpp::SHT_RELA, true,
                            size, big_endian> Reloc_section;

  Output_data_plt_powerpc(Layout*);

  // Add an entry to the PLT.
  void add_entry(Symbol* gsym);

  // Return the .rela.plt section data.
  const Reloc_section* rel_plt() const
 {
    return this->rel_;
  }

 protected:
  void do_adjust_output_section(Output_section* os);

 private:
  // The size of an entry in the PLT.
  static const int base_plt_entry_size = (size == 32 ? 16 : 24);

  // Set the final size.
  void
  set_final_data_size()
  {
    unsigned int full_count = this->count_ + 4;

    this->set_data_size(full_count * base_plt_entry_size);
  }

  // Write out the PLT data.
  void
  do_write(Output_file*);

  // The reloc section.
  Reloc_section* rel_;
  // The number of PLT entries.
  unsigned int count_;
};

// Create the PLT section.  The ordinary .got section is an argument,
// since we need to refer to the start.

template<int size, bool big_endian>
Output_data_plt_powerpc<size, big_endian>::Output_data_plt_powerpc(Layout* layout)
  : Output_section_data(size == 32 ? 4 : 8), count_(0)
{
  this->rel_ = new Reloc_section(false);
  layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
                                  elfcpp::SHF_ALLOC, this->rel_, true);
}

template<int size, bool big_endian>
void
Output_data_plt_powerpc<size, big_endian>::do_adjust_output_section(Output_section* os)
{
  os->set_entsize(0);
}

// Add an entry to the PLT.

template<int size, bool big_endian>
void
Output_data_plt_powerpc<size, big_endian>::add_entry(Symbol* gsym)
{
  gold_assert(!gsym->has_plt_offset());
  unsigned int index = this->count_+ + 4;
  section_offset_type plt_offset;

  if (index < 8192)
    plt_offset = index * base_plt_entry_size;
  else
    gold_unreachable();

  gsym->set_plt_offset(plt_offset);

  ++this->count_;

  gsym->set_needs_dynsym_entry();
  this->rel_->add_global(gsym, elfcpp::R_POWERPC_JMP_SLOT, this,
                         plt_offset, 0);
}

static const unsigned int addis_11_11     = 0x3d6b0000;
static const unsigned int addis_11_30     = 0x3d7e0000;
static const unsigned int addis_12_12     = 0x3d8c0000;
static const unsigned int addi_11_11      = 0x396b0000;
static const unsigned int add_0_11_11     = 0x7c0b5a14;
static const unsigned int add_11_0_11     = 0x7d605a14;
static const unsigned int b               = 0x48000000;
static const unsigned int bcl_20_31       = 0x429f0005;
static const unsigned int bctr            = 0x4e800420;
static const unsigned int lis_11          = 0x3d600000;
static const unsigned int lis_12          = 0x3d800000;
static const unsigned int lwzu_0_12       = 0x840c0000;
static const unsigned int lwz_0_12        = 0x800c0000;
static const unsigned int lwz_11_11       = 0x816b0000;
static const unsigned int lwz_11_30       = 0x817e0000;
static const unsigned int lwz_12_12       = 0x818c0000;
static const unsigned int mflr_0          = 0x7c0802a6;
static const unsigned int mflr_12         = 0x7d8802a6;
static const unsigned int mtctr_0         = 0x7c0903a6;
static const unsigned int mtctr_11        = 0x7d6903a6;
static const unsigned int mtlr_0          = 0x7c0803a6;
static const unsigned int nop             = 0x60000000;
static const unsigned int sub_11_11_12    = 0x7d6c5850;

static const unsigned int addis_r12_r2    = 0x3d820000;  /* addis %r12,%r2,xxx@ha     */
static const unsigned int std_r2_40r1     = 0xf8410028;  /* std   %r2,40(%r1)         */
static const unsigned int ld_r11_0r12     = 0xe96c0000;  /* ld    %r11,xxx+0@l(%r12)  */
static const unsigned int ld_r2_0r12      = 0xe84c0000;  /* ld    %r2,xxx+8@l(%r12)   */
                                                         /* ld    %r11,xxx+16@l(%r12) */


// Write out the PLT.

template<int size, bool big_endian>
void
Output_data_plt_powerpc<size, big_endian>::do_write(Output_file* of)
{
  const off_t offset = this->offset();
  const section_size_type oview_size =
    convert_to_section_size_type(this->data_size());
  unsigned char* const oview = of->get_output_view(offset, oview_size);
  unsigned char* pov = oview;

  memset(pov, 0, base_plt_entry_size * 4);
  pov += base_plt_entry_size * 4;

  unsigned int plt_offset = base_plt_entry_size * 4;
  const unsigned int count = this->count_;

  if (size == 64)
    {
      for (unsigned int i = 0; i < count; i++)
        {
        }
    }
  else
    {
      for (unsigned int i = 0; i < count; i++)
        {
          elfcpp::Swap<32, true>::writeval(pov + 0x00,
                                           lwz_11_30 + plt_offset);
          elfcpp::Swap<32, true>::writeval(pov + 0x04, mtctr_11);
          elfcpp::Swap<32, true>::writeval(pov + 0x08, bctr);
          elfcpp::Swap<32, true>::writeval(pov + 0x0c, nop);
          pov += base_plt_entry_size;
          plt_offset += base_plt_entry_size;
        }
    }

  gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);

  of->write_output_view(offset, oview_size, oview);
}

// Create a PLT entry for a global symbol.

template<int size, bool big_endian>
void
Target_powerpc<size, big_endian>::make_plt_entry(Symbol_table* symtab,
                                                 Layout* layout,
                                                 Symbol* gsym)
{
  if (gsym->has_plt_offset())
    return;

  if (this->plt_ == NULL)
    {
      // Create the GOT section first.
      this->got_section(symtab, layout);

      this->plt_ = new Output_data_plt_powerpc<size, big_endian>(layout);
      layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
                                      (elfcpp::SHF_ALLOC
                                       | elfcpp::SHF_EXECINSTR
                                       | elfcpp::SHF_WRITE),
                                      this->plt_, false);

      // Define _PROCEDURE_LINKAGE_TABLE_ at the start of the .plt section.
      symtab->define_in_output_data("_PROCEDURE_LINKAGE_TABLE_", NULL,
                                    Symbol_table::PREDEFINED,
                                    this->plt_,
                                    0, 0, elfcpp::STT_OBJECT,
                                    elfcpp::STB_LOCAL,
                                    elfcpp::STV_HIDDEN, 0,
                                    false, false);
    }

  this->plt_->add_entry(gsym);
}

// Create a GOT entry for the TLS module index.

template<int size, bool big_endian>
unsigned int
Target_powerpc<size, big_endian>::got_mod_index_entry(Symbol_table* symtab,
                                                      Layout* layout,
                                                      Sized_relobj<size, big_endian>* object)
{
  if (this->got_mod_index_offset_ == -1U)
    {
      gold_assert(symtab != NULL && layout != NULL && object != NULL);
      Reloc_section* rela_dyn = this->rela_dyn_section(layout);
      Output_data_got<size, big_endian>* got;
      unsigned int got_offset;

      got = this->got_section(symtab, layout);
      got_offset = got->add_constant(0);
      rela_dyn->add_local(object, 0, elfcpp::R_POWERPC_DTPMOD, got,
                          got_offset, 0);
      got->add_constant(0);
      this->got_mod_index_offset_ = got_offset;
    }
  return this->got_mod_index_offset_;
}

// Optimize the TLS relocation type based on what we know about the
// symbol.  IS_FINAL is true if the final address of this symbol is
// known at link time.

static tls::Tls_optimization
optimize_tls_reloc(bool /* is_final */, int r_type)
{
  // If we are generating a shared library, then we can't do anything
  // in the linker.
  if (parameters->options().shared())
    return tls::TLSOPT_NONE;
  switch (r_type)
    {
      // XXX
    default:
      gold_unreachable();
    }
}

// Report an unsupported relocation against a local symbol.

template<int size, bool big_endian>
void
Target_powerpc<size, big_endian>::Scan::unsupported_reloc_local(
                        Sized_relobj<size, big_endian>* object,
                        unsigned int r_type)
{
  gold_error(_("%s: unsupported reloc %u against local symbol"),
             object->name().c_str(), r_type);
}

// We are about to emit a dynamic relocation of type R_TYPE.  If the
// dynamic linker does not support it, issue an error.

template<int size, bool big_endian>
void
Target_powerpc<size, big_endian>::Scan::check_non_pic(Relobj* object,
                                                      unsigned int r_type)
{
  gold_assert(r_type != elfcpp::R_POWERPC_NONE);

  // These are the relocation types supported by glibc for both 32-bit
  // and 64-bit powerpc.
  switch (r_type)
    {
    case elfcpp::R_POWERPC_RELATIVE:
    case elfcpp::R_POWERPC_GLOB_DAT:
    case elfcpp::R_POWERPC_DTPMOD:
    case elfcpp::R_POWERPC_DTPREL:
    case elfcpp::R_POWERPC_TPREL:
    case elfcpp::R_POWERPC_JMP_SLOT:
    case elfcpp::R_POWERPC_COPY:
    case elfcpp::R_POWERPC_ADDR32:
    case elfcpp::R_POWERPC_ADDR24:
    case elfcpp::R_POWERPC_REL24:
      return;

    default:
      break;
    }

  if (size == 64)
    {
      switch (r_type)
        {
          // These are the relocation types supported only on 64-bit.
        case elfcpp::R_PPC64_ADDR64:
        case elfcpp::R_PPC64_TPREL16_LO_DS:
        case elfcpp::R_PPC64_TPREL16_DS:
        case elfcpp::R_POWERPC_TPREL16:
        case elfcpp::R_POWERPC_TPREL16_LO:
        case elfcpp::R_POWERPC_TPREL16_HI:
        case elfcpp::R_POWERPC_TPREL16_HA:
        case elfcpp::R_PPC64_TPREL16_HIGHER:
        case elfcpp::R_PPC64_TPREL16_HIGHEST:
        case elfcpp::R_PPC64_TPREL16_HIGHERA:
        case elfcpp::R_PPC64_TPREL16_HIGHESTA:
        case elfcpp::R_PPC64_ADDR16_LO_DS:
        case elfcpp::R_POWERPC_ADDR16_LO:
        case elfcpp::R_POWERPC_ADDR16_HI:
        case elfcpp::R_POWERPC_ADDR16_HA:
        case elfcpp::R_POWERPC_ADDR30:
        case elfcpp::R_PPC64_UADDR64:
        case elfcpp::R_POWERPC_UADDR32:
        case elfcpp::R_POWERPC_ADDR16:
        case elfcpp::R_POWERPC_UADDR16:
        case elfcpp::R_PPC64_ADDR16_DS:
        case elfcpp::R_PPC64_ADDR16_HIGHER:
        case elfcpp::R_PPC64_ADDR16_HIGHEST:
        case elfcpp::R_PPC64_ADDR16_HIGHERA:
        case elfcpp::R_PPC64_ADDR16_HIGHESTA:
        case elfcpp::R_POWERPC_ADDR14_BRTAKEN:
        case elfcpp::R_POWERPC_ADDR14_BRNTAKEN:
        case elfcpp::R_POWERPC_REL32:
        case elfcpp::R_PPC64_REL64:
          return;

        default:
          break;
        }
    }
  else
    {
      switch (r_type)
        {
          // These are the relocation types supported only on 32-bit.

        default:
          break;
        }
    }

  // This prevents us from issuing more than one error per reloc
  // section.  But we can still wind up issuing more than one
  // error per object file.
  if (this->issued_non_pic_error_)
    return;
  gold_assert(parameters->options().output_is_position_independent());
  object->error(_("requires unsupported dynamic reloc; "
                  "recompile with -fPIC"));
  this->issued_non_pic_error_ = true;
  return;
}

// Scan a relocation for a local symbol.

template<int size, bool big_endian>
inline void
Target_powerpc<size, big_endian>::Scan::local(
                        Symbol_table* symtab,
                        Layout* layout,
                        Target_powerpc<size, big_endian>* target,
                        Sized_relobj<size, big_endian>* object,
                        unsigned int data_shndx,
                        Output_section* output_section,
                        const elfcpp::Rela<size, big_endian>& reloc,
                        unsigned int r_type,
                        const elfcpp::Sym<size, big_endian>& lsym)
{
  switch (r_type)
    {
    case elfcpp::R_POWERPC_NONE:
    case elfcpp::R_POWERPC_GNU_VTINHERIT:
    case elfcpp::R_POWERPC_GNU_VTENTRY:
      break;

    case elfcpp::R_PPC64_ADDR64:
    case elfcpp::R_POWERPC_ADDR32:
    case elfcpp::R_POWERPC_ADDR16_HA:
    case elfcpp::R_POWERPC_ADDR16_LO:
      // If building a shared library (or a position-independent
      // executable), we need to create a dynamic relocation for
      // this location.
      if (parameters->options().output_is_position_independent())
        {
          Reloc_section* rela_dyn = target->rela_dyn_section(layout);

          check_non_pic(object, r_type);
          if (lsym.get_st_type() != elfcpp::STT_SECTION)
            {
              unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
              rela_dyn->add_local(object, r_sym, r_type, output_section,
                                  data_shndx, reloc.get_r_offset(),
                                  reloc.get_r_addend());
            }
          else
            {
              unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
              gold_assert(lsym.get_st_value() == 0);
              rela_dyn->add_local_relative(object, r_sym, r_type,
                                           output_section, data_shndx,
                                           reloc.get_r_offset(),
                                           reloc.get_r_addend());
            }
        }
      break;

    case elfcpp::R_POWERPC_REL24:
    case elfcpp::R_PPC_LOCAL24PC:
    case elfcpp::R_POWERPC_REL32:
    case elfcpp::R_PPC_REL16_LO:
    case elfcpp::R_PPC_REL16_HA:
      break;

    case elfcpp::R_POWERPC_GOT16:
    case elfcpp::R_POWERPC_GOT16_LO:
    case elfcpp::R_POWERPC_GOT16_HI:
    case elfcpp::R_POWERPC_GOT16_HA:
    case elfcpp::R_PPC64_TOC16:
    case elfcpp::R_PPC64_TOC16_LO:
    case elfcpp::R_PPC64_TOC16_HI:
    case elfcpp::R_PPC64_TOC16_HA:
    case elfcpp::R_PPC64_TOC16_DS:
    case elfcpp::R_PPC64_TOC16_LO_DS:
      {
        // The symbol requires a GOT entry.
        Output_data_got<size, big_endian>* got;
        unsigned int r_sym;

        got = target->got_section(symtab, layout);
        r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());

        // If we are generating a shared object, we need to add a
        // dynamic relocation for this symbol's GOT entry.
        if (parameters->options().output_is_position_independent())
          {
            if (!object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD))
              {
                Reloc_section* rela_dyn = target->rela_dyn_section(layout);
                unsigned int off;

                off = got->add_constant(0);
                object->set_local_got_offset(r_sym, GOT_TYPE_STANDARD, off);
                rela_dyn->add_local_relative(object, r_sym,
                                             elfcpp::R_POWERPC_RELATIVE,
                                             got, off, 0);
              }
          }
        else
          got->add_local(object, r_sym, GOT_TYPE_STANDARD);
      }
      break;

    case elfcpp::R_PPC64_TOC:
      // We need a GOT section.
      target->got_section(symtab, layout);
      break;

      // These are relocations which should only be seen by the
      // dynamic linker, and should never be seen here.
    case elfcpp::R_POWERPC_COPY:
    case elfcpp::R_POWERPC_GLOB_DAT:
    case elfcpp::R_POWERPC_JMP_SLOT:
    case elfcpp::R_POWERPC_RELATIVE:
    case elfcpp::R_POWERPC_DTPMOD:
      gold_error(_("%s: unexpected reloc %u in object file"),
                 object->name().c_str(), r_type);
      break;

    default:
      unsupported_reloc_local(object, r_type);
      break;
    }
}

// Report an unsupported relocation against a global symbol.

template<int size, bool big_endian>
void
Target_powerpc<size, big_endian>::Scan::unsupported_reloc_global(
                        Sized_relobj<size, big_endian>* object,
                        unsigned int r_type,
                        Symbol* gsym)
{
  gold_error(_("%s: unsupported reloc %u against global symbol %s"),
             object->name().c_str(), r_type, gsym->demangled_name().c_str());
}

// Scan a relocation for a global symbol.

template<int size, bool big_endian>
inline void
Target_powerpc<size, big_endian>::Scan::global(
                                Symbol_table* symtab,
                                Layout* layout,
                                Target_powerpc<size, big_endian>* target,
                                Sized_relobj<size, big_endian>* object,
                                unsigned int data_shndx,
                                Output_section* output_section,
                                const elfcpp::Rela<size, big_endian>& reloc,
                                unsigned int r_type,
                                Symbol* gsym)
{
  switch (r_type)
    {
    case elfcpp::R_POWERPC_NONE:
    case elfcpp::R_POWERPC_GNU_VTINHERIT:
    case elfcpp::R_POWERPC_GNU_VTENTRY:
      break;

    case elfcpp::R_PPC_PLTREL24:
      // If the symbol is fully resolved, this is just a PC32 reloc.
      // Otherwise we need a PLT entry.
      if (gsym->final_value_is_known())
        break;
      // If building a shared library, we can also skip the PLT entry
      // if the symbol is defined in the output file and is protected
      // or hidden.
      if (gsym->is_defined()
          && !gsym->is_from_dynobj()
          && !gsym->is_preemptible())
        break;
      target->make_plt_entry(symtab, layout, gsym);
      break;

    case elfcpp::R_POWERPC_ADDR16:
    case elfcpp::R_POWERPC_ADDR16_LO:
    case elfcpp::R_POWERPC_ADDR16_HI:
    case elfcpp::R_POWERPC_ADDR16_HA:
    case elfcpp::R_POWERPC_ADDR32:
    case elfcpp::R_PPC64_ADDR64:
      {
        // Make a PLT entry if necessary.
        if (gsym->needs_plt_entry())
          {
            target->make_plt_entry(symtab, layout, gsym);
            // Since this is not a PC-relative relocation, we may be
            // taking the address of a function. In that case we need to
            // set the entry in the dynamic symbol table to the address of
            // the PLT entry.
            if (gsym->is_from_dynobj() && !parameters->options().shared())
              gsym->set_needs_dynsym_value();
          }
        // Make a dynamic relocation if necessary.
        if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
          {
            if (gsym->may_need_copy_reloc())
              {
                target->copy_reloc(symtab, layout, object,
                                   data_shndx, output_section, gsym, reloc);
              }
            else if ((r_type == elfcpp::R_POWERPC_ADDR32
                      || r_type == elfcpp::R_PPC64_ADDR64)
                     && gsym->can_use_relative_reloc(false))
              {
                Reloc_section* rela_dyn = target->rela_dyn_section(layout);
                rela_dyn->add_global_relative(gsym, elfcpp::R_POWERPC_RELATIVE,
                                              output_section, object,
                                              data_shndx, reloc.get_r_offset(),
                                              reloc.get_r_addend());
              }
            else
              {
                Reloc_section* rela_dyn = target->rela_dyn_section(layout);

                check_non_pic(object, r_type);
                if (gsym->is_from_dynobj()
                    || gsym->is_undefined()
                    || gsym->is_preemptible())
                  rela_dyn->add_global(gsym, r_type, output_section,
                                       object, data_shndx,
                                       reloc.get_r_offset(),
                                       reloc.get_r_addend());
                else
                  rela_dyn->add_global_relative(gsym, r_type,
                                                output_section, object,
                                                data_shndx,
                                                reloc.get_r_offset(),
                                                reloc.get_r_addend());
              }
          }
      }
      break;

    case elfcpp::R_POWERPC_REL24:
    case elfcpp::R_PPC_LOCAL24PC:
    case elfcpp::R_PPC_REL16:
    case elfcpp::R_PPC_REL16_LO:
    case elfcpp::R_PPC_REL16_HI:
    case elfcpp::R_PPC_REL16_HA:
      {
        if (gsym->needs_plt_entry())
          target->make_plt_entry(symtab, layout, gsym);
        // Make a dynamic relocation if necessary.
        int flags = Symbol::NON_PIC_REF;
        if (gsym->type() == elfcpp::STT_FUNC)
          flags |= Symbol::FUNCTION_CALL;
        if (gsym->needs_dynamic_reloc(flags))
          {
            if (gsym->may_need_copy_reloc())
              {
                target->copy_reloc(symtab, layout, object,
                                   data_shndx, output_section, gsym,
                                   reloc);
              }
            else
              {
                Reloc_section* rela_dyn = target->rela_dyn_section(layout);
                check_non_pic(object, r_type);
                rela_dyn->add_global(gsym, r_type, output_section, object,
                                     data_shndx, reloc.get_r_offset(),
                                     reloc.get_r_addend());
              }
          }
      }
      break;

    case elfcpp::R_POWERPC_GOT16:
    case elfcpp::R_POWERPC_GOT16_LO:
    case elfcpp::R_POWERPC_GOT16_HI:
    case elfcpp::R_POWERPC_GOT16_HA:
    case elfcpp::R_PPC64_TOC16:
    case elfcpp::R_PPC64_TOC16_LO:
    case elfcpp::R_PPC64_TOC16_HI:
    case elfcpp::R_PPC64_TOC16_HA:
    case elfcpp::R_PPC64_TOC16_DS:
    case elfcpp::R_PPC64_TOC16_LO_DS:
      {
        // The symbol requires a GOT entry.
        Output_data_got<size, big_endian>* got;

        got = target->got_section(symtab, layout);
        if (gsym->final_value_is_known())
          got->add_global(gsym, GOT_TYPE_STANDARD);
        else
          {
            // If this symbol is not fully resolved, we need to add a
            // dynamic relocation for it.
            Reloc_section* rela_dyn = target->rela_dyn_section(layout);
            if (gsym->is_from_dynobj()
                || gsym->is_undefined()
                || gsym->is_preemptible())
              got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
                                        elfcpp::R_POWERPC_GLOB_DAT);
            else if (!gsym->has_got_offset(GOT_TYPE_STANDARD))
              {
                unsigned int off = got->add_constant(0);

                gsym->set_got_offset(GOT_TYPE_STANDARD, off);
                rela_dyn->add_global_relative(gsym, elfcpp::R_POWERPC_RELATIVE,
                                              got, off, 0);
              }
          }
      }
      break;

    case elfcpp::R_PPC64_TOC:
      // We need a GOT section.
      target->got_section(symtab, layout);
      break;

    case elfcpp::R_POWERPC_GOT_TPREL16:
    case elfcpp::R_POWERPC_TLS:
      // XXX TLS
      break;

      // These are relocations which should only be seen by the
      // dynamic linker, and should never be seen here.
    case elfcpp::R_POWERPC_COPY:
    case elfcpp::R_POWERPC_GLOB_DAT:
    case elfcpp::R_POWERPC_JMP_SLOT:
    case elfcpp::R_POWERPC_RELATIVE:
    case elfcpp::R_POWERPC_DTPMOD:
      gold_error(_("%s: unexpected reloc %u in object file"),
                 object->name().c_str(), r_type);
      break;

    default:
      unsupported_reloc_global(object, r_type, gsym);
      break;
    }
}

// Process relocations for gc.

template<int size, bool big_endian>
void
Target_powerpc<size, big_endian>::gc_process_relocs(
                        Symbol_table* symtab,
                        Layout* layout,
                        Sized_relobj<size, big_endian>* object,
                        unsigned int data_shndx,
                        unsigned int,
                        const unsigned char* prelocs,
                        size_t reloc_count,
                        Output_section* output_section,
                        bool needs_special_offset_handling,
                        size_t local_symbol_count,
                        const unsigned char* plocal_symbols)
{
  typedef Target_powerpc<size, big_endian> Powerpc;
  typedef typename Target_powerpc<size, big_endian>::Scan Scan;

  gold::gc_process_relocs<size, big_endian, Powerpc, elfcpp::SHT_RELA, Scan>(
    symtab,
    layout,
    this,
    object,
    data_shndx,
    prelocs,
    reloc_count,
    output_section,
    needs_special_offset_handling,
    local_symbol_count,
    plocal_symbols);
}

// Scan relocations for a section.

template<int size, bool big_endian>
void
Target_powerpc<size, big_endian>::scan_relocs(
                        Symbol_table* symtab,
                        Layout* layout,
                        Sized_relobj<size, big_endian>* object,
                        unsigned int data_shndx,
                        unsigned int sh_type,
                        const unsigned char* prelocs,
                        size_t reloc_count,
                        Output_section* output_section,
                        bool needs_special_offset_handling,
                        size_t local_symbol_count,
                        const unsigned char* plocal_symbols)
{
  typedef Target_powerpc<size, big_endian> Powerpc;
  typedef typename Target_powerpc<size, big_endian>::Scan Scan;
  static Output_data_space* sdata;

  if (sh_type == elfcpp::SHT_REL)
    {
      gold_error(_("%s: unsupported REL reloc section"),
                 object->name().c_str());
      return;
    }

  // Define _SDA_BASE_ at the start of the .sdata section.
  if (sdata == NULL)
  {
    // layout->find_output_section(".sdata") == NULL
    sdata = new Output_data_space(4, "** sdata");
    Output_section* os = layout->add_output_section_data(".sdata", 0,
                                                         elfcpp::SHF_ALLOC
                                                         | elfcpp::SHF_WRITE,
                                                         sdata, false);
    symtab->define_in_output_data("_SDA_BASE_", NULL,
                                  Symbol_table::PREDEFINED,
                                  os,
                                  32768, 0,
                                  elfcpp::STT_OBJECT,
                                  elfcpp::STB_LOCAL,
                                  elfcpp::STV_HIDDEN, 0,
                                  false, false);
  }

  gold::scan_relocs<size, big_endian, Powerpc, elfcpp::SHT_RELA, Scan>(
    symtab,
    layout,
    this,
    object,
    data_shndx,
    prelocs,
    reloc_count,
    output_section,
    needs_special_offset_handling,
    local_symbol_count,
    plocal_symbols);
}

// Finalize the sections.

template<int size, bool big_endian>
void
Target_powerpc<size, big_endian>::do_finalize_sections(
    Layout* layout,
    const Input_objects*,
    Symbol_table*)
{
  // Fill in some more dynamic tags.
  Output_data_dynamic* const odyn = layout->dynamic_data();
  if (odyn != NULL)
    {
      if (this->plt_ != NULL
          && this->plt_->output_section() != NULL)
        {
          const Output_data* od = this->plt_->rel_plt();
          odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
          odyn->add_section_address(elfcpp::DT_JMPREL, od);
          odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_RELA);

          odyn->add_section_address(elfcpp::DT_PLTGOT, this->plt_);
        }

      if (this->rela_dyn_ != NULL
          && this->rela_dyn_->output_section() != NULL)
        {
          const Output_data* od = this->rela_dyn_;
          odyn->add_section_address(elfcpp::DT_RELA, od);
          odyn->add_section_size(elfcpp::DT_RELASZ, od);
          odyn->add_constant(elfcpp::DT_RELAENT,
                             elfcpp::Elf_sizes<size>::rela_size);
        }

      if (!parameters->options().shared())
        {
          // The value of the DT_DEBUG tag is filled in by the dynamic
          // linker at run time, and used by the debugger.
          odyn->add_constant(elfcpp::DT_DEBUG, 0);
        }
    }

  // Emit any relocs we saved in an attempt to avoid generating COPY
  // relocs.
  if (this->copy_relocs_.any_saved_relocs())
    this->copy_relocs_.emit(this->rela_dyn_section(layout));
}

// Perform a relocation.

template<int size, bool big_endian>
inline bool
Target_powerpc<size, big_endian>::Relocate::relocate(
                        const Relocate_info<size, big_endian>* relinfo,
                        Target_powerpc* target,
                        Output_section*,
                        size_t relnum,
                        const elfcpp::Rela<size, big_endian>& rela,
                        unsigned int r_type,
                        const Sized_symbol<size>* gsym,
                        const Symbol_value<size>* psymval,
                        unsigned char* view,
                        typename elfcpp::Elf_types<size>::Elf_Addr address,
                        section_size_type /* view_size */)
{
  const unsigned int toc_base_offset = 0x8000;
  typedef Powerpc_relocate_functions<size, big_endian> Reloc;

  // Pick the value to use for symbols defined in shared objects.
  Symbol_value<size> symval;
  if (gsym != NULL
      && gsym->use_plt_offset(r_type == elfcpp::R_POWERPC_REL24
                              || r_type == elfcpp::R_PPC_LOCAL24PC
                              || r_type == elfcpp::R_PPC_REL16
                              || r_type == elfcpp::R_PPC_REL16_LO
                              || r_type == elfcpp::R_PPC_REL16_HI
                              || r_type == elfcpp::R_PPC_REL16_HA))
    {
      elfcpp::Elf_Xword value;

      value = target->plt_section()->address() + gsym->plt_offset();

      symval.set_output_value(value);

      psymval = &symval;
    }

  const Sized_relobj<size, big_endian>* object = relinfo->object;
  elfcpp::Elf_Xword addend = rela.get_r_addend();

  // Get the GOT offset if needed.  Unlike i386 and x86_64, our GOT
  // pointer points to the beginning, not the end, of the table.
  // So we just use the plain offset.
  bool have_got_offset = false;
  unsigned int got_offset = 0;
  unsigned int got2_offset = 0;
  switch (r_type)
    {
    case elfcpp::R_PPC64_TOC16:
    case elfcpp::R_PPC64_TOC16_LO:
    case elfcpp::R_PPC64_TOC16_HI:
    case elfcpp::R_PPC64_TOC16_HA:
    case elfcpp::R_PPC64_TOC16_DS:
    case elfcpp::R_PPC64_TOC16_LO_DS:
        // Subtract the TOC base address.
        addend -= target->toc_section()->address() + toc_base_offset;
        /* FALLTHRU */

    case elfcpp::R_POWERPC_GOT16:
    case elfcpp::R_POWERPC_GOT16_LO:
    case elfcpp::R_POWERPC_GOT16_HI:
    case elfcpp::R_POWERPC_GOT16_HA:
    case elfcpp::R_PPC64_GOT16_DS:
    case elfcpp::R_PPC64_GOT16_LO_DS:
      if (gsym != NULL)
        {
          gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
          got_offset = gsym->got_offset(GOT_TYPE_STANDARD);
        }
      else
        {
          unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
          gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
          got_offset = object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
        }
      have_got_offset = true;
      break;

      // R_PPC_PLTREL24 is rather special.  If non-zero,
      // the addend specifies the GOT pointer offset within .got2.  
    case elfcpp::R_PPC_PLTREL24:
      if (addend >= 32768)
        {
          Output_data_space* got2;
          got2 = target->got2_section();
          got2_offset = got2->offset();
          addend += got2_offset;
        }
      have_got_offset = true;
      break;

    default:
      break;
    }

  switch (r_type)
    {
    case elfcpp::R_POWERPC_NONE:
    case elfcpp::R_POWERPC_GNU_VTINHERIT:
    case elfcpp::R_POWERPC_GNU_VTENTRY:
      break;

    case elfcpp::R_POWERPC_REL32:
      Reloc::rel32(view, object, psymval, addend, address);
      break;

    case elfcpp::R_POWERPC_REL24:
      Reloc::rel24(view, object, psymval, addend, address);
      break;

    case elfcpp::R_POWERPC_REL14:
      Reloc::rel14(view, object, psymval, addend, address);
      break;

    case elfcpp::R_PPC_PLTREL24:
      Reloc::rel24(view, object, psymval, addend, address);
      break;

    case elfcpp::R_PPC_LOCAL24PC:
      Reloc::rel24(view, object, psymval, addend, address);
      break;

    case elfcpp::R_PPC64_ADDR64:
      if (!parameters->options().output_is_position_independent())
        Relocate_functions<size, big_endian>::rela64(view, object,
                                                     psymval, addend);
      break;

    case elfcpp::R_POWERPC_ADDR32:
      if (!parameters->options().output_is_position_independent())
        Relocate_functions<size, big_endian>::rela32(view, object,
                                                     psymval, addend);
      break;

    case elfcpp::R_POWERPC_ADDR16_LO:
      Reloc::addr16_lo(view, object, psymval, addend);
      break;

    case elfcpp::R_POWERPC_ADDR16_HI:
      Reloc::addr16_hi(view, object, psymval, addend);
      break;

    case elfcpp::R_POWERPC_ADDR16_HA:
      Reloc::addr16_ha(view, object, psymval, addend);
      break;

    case elfcpp::R_PPC_REL16_LO:
      Reloc::rel16_lo(view, object, psymval, addend, address);
      break;

    case elfcpp::R_PPC_REL16_HI:
      Reloc::rel16_lo(view, object, psymval, addend, address);
      break;

    case elfcpp::R_PPC_REL16_HA:
      Reloc::rel16_ha(view, object, psymval, addend, address);
      break;

    case elfcpp::R_POWERPC_GOT16:
      Reloc::addr16(view, got_offset, addend);
      break;

    case elfcpp::R_POWERPC_GOT16_LO:
      Reloc::addr16_lo(view, got_offset, addend);
      break;

    case elfcpp::R_POWERPC_GOT16_HI:
      Reloc::addr16_hi(view, got_offset, addend);
      break;

    case elfcpp::R_POWERPC_GOT16_HA:
      Reloc::addr16_ha(view, got_offset, addend);
      break;

    case elfcpp::R_PPC64_TOC16:
      Reloc::addr16(view, got_offset, addend);
      break;

    case elfcpp::R_PPC64_TOC16_LO:
      Reloc::addr16_lo(view, got_offset, addend);
      break;

    case elfcpp::R_PPC64_TOC16_HI:
      Reloc::addr16_hi(view, got_offset, addend);
      break;

    case elfcpp::R_PPC64_TOC16_HA:
      Reloc::addr16_ha(view, got_offset, addend);
      break;

    case elfcpp::R_PPC64_TOC16_DS:
    case elfcpp::R_PPC64_TOC16_LO_DS:
      Reloc::addr16_ds(view, got_offset, addend);
      break;

    case elfcpp::R_PPC64_TOC:
      {
        elfcpp::Elf_types<64>::Elf_Addr value;
        value = target->toc_section()->address() + toc_base_offset;
        Relocate_functions<64, false>::rela64(view, value, addend);
      }
      break;

    case elfcpp::R_POWERPC_COPY:
    case elfcpp::R_POWERPC_GLOB_DAT:
    case elfcpp::R_POWERPC_JMP_SLOT:
    case elfcpp::R_POWERPC_RELATIVE:
      // This is an outstanding tls reloc, which is unexpected when
      // linking.
    case elfcpp::R_POWERPC_DTPMOD:
      gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
                             _("unexpected reloc %u in object file"),
                             r_type);
      break;

    default:
      gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
                             _("unsupported reloc %u"),
                             r_type);
      break;
    }

  return true;
}

// Perform a TLS relocation.

template<int size, bool big_endian>
inline void
Target_powerpc<size, big_endian>::Relocate::relocate_tls(
                        const Relocate_info<size, big_endian>* relinfo,
                        Target_powerpc<size, big_endian>* target,
                        size_t relnum,
                        const elfcpp::Rela<size, big_endian>& rela,
                        unsigned int r_type,
                        const Sized_symbol<size>* gsym,
                        const Symbol_value<size>* psymval,
                        unsigned char* view,
                        typename elfcpp::Elf_types<size>::Elf_Addr address,
                        section_size_type)
{
  Output_segment* tls_segment = relinfo->layout->tls_segment();
  typedef Powerpc_relocate_functions<size, big_endian> Reloc;
  const Sized_relobj<size, big_endian>* object = relinfo->object;

  const elfcpp::Elf_Xword addend = rela.get_r_addend();
  typename elfcpp::Elf_types<size>::Elf_Addr value = psymval->value(object, 0);

  const bool is_final =
    (gsym == NULL
     ? !parameters->options().output_is_position_independent()
     : gsym->final_value_is_known());
  const tls::Tls_optimization optimized_type
      = optimize_tls_reloc(is_final, r_type);

  switch (r_type)
    {
      // XXX
    }
}

// Relocate section data.

template<int size, bool big_endian>
void
Target_powerpc<size, big_endian>::relocate_section(
                        const Relocate_info<size, big_endian>* relinfo,
                        unsigned int sh_type,
                        const unsigned char* prelocs,
                        size_t reloc_count,
                        Output_section* output_section,
                        bool needs_special_offset_handling,
                        unsigned char* view,
                        typename elfcpp::Elf_types<size>::Elf_Addr address,
                        section_size_type view_size,
                        const Reloc_symbol_changes* reloc_symbol_changes)
{
  typedef Target_powerpc<size, big_endian> Powerpc;
  typedef typename Target_powerpc<size, big_endian>::Relocate Powerpc_relocate;

  gold_assert(sh_type == elfcpp::SHT_RELA);

  gold::relocate_section<size, big_endian, Powerpc, elfcpp::SHT_RELA,
    Powerpc_relocate>(
    relinfo,
    this,
    prelocs,
    reloc_count,
    output_section,
    needs_special_offset_handling,
    view,
    address,
    view_size,
    reloc_symbol_changes);
}

// Return the size of a relocation while scanning during a relocatable
// link.

template<int size, bool big_endian>
unsigned int
Target_powerpc<size, big_endian>::Relocatable_size_for_reloc::get_size_for_reloc(
    unsigned int,
    Relobj*)
{
  // We are always SHT_RELA, so we should never get here.
  gold_unreachable();
  return 0;
}

// Scan the relocs during a relocatable link.

template<int size, bool big_endian>
void
Target_powerpc<size, big_endian>::scan_relocatable_relocs(
                        Symbol_table* symtab,
                        Layout* layout,
                        Sized_relobj<size, big_endian>* object,
                        unsigned int data_shndx,
                        unsigned int sh_type,
                        const unsigned char* prelocs,
                        size_t reloc_count,
                        Output_section* output_section,
                        bool needs_special_offset_handling,
                        size_t local_symbol_count,
                        const unsigned char* plocal_symbols,
                        Relocatable_relocs* rr)
{
  gold_assert(sh_type == elfcpp::SHT_RELA);

  typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
    Relocatable_size_for_reloc> Scan_relocatable_relocs;

  gold::scan_relocatable_relocs<size, big_endian, elfcpp::SHT_RELA,
      Scan_relocatable_relocs>(
    symtab,
    layout,
    object,
    data_shndx,
    prelocs,
    reloc_count,
    output_section,
    needs_special_offset_handling,
    local_symbol_count,
    plocal_symbols,
    rr);
}

// Relocate a section during a relocatable link.

template<int size, bool big_endian>
void
Target_powerpc<size, big_endian>::relocate_for_relocatable(
    const Relocate_info<size, big_endian>* relinfo,
    unsigned int sh_type,
    const unsigned char* prelocs,
    size_t reloc_count,
    Output_section* output_section,
    off_t offset_in_output_section,
    const Relocatable_relocs* rr,
    unsigned char* view,
    typename elfcpp::Elf_types<size>::Elf_Addr view_address,
    section_size_type view_size,
    unsigned char* reloc_view,
    section_size_type reloc_view_size)
{
  gold_assert(sh_type == elfcpp::SHT_RELA);

  gold::relocate_for_relocatable<size, big_endian, elfcpp::SHT_RELA>(
    relinfo,
    prelocs,
    reloc_count,
    output_section,
    offset_in_output_section,
    rr,
    view,
    view_address,
    view_size,
    reloc_view,
    reloc_view_size);
}

// Return the value to use for a dynamic which requires special
// treatment.  This is how we support equality comparisons of function
// pointers across shared library boundaries, as described in the
// processor specific ABI supplement.

template<int size, bool big_endian>
uint64_t
Target_powerpc<size, big_endian>::do_dynsym_value(const Symbol* gsym) const
{
  gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
  return this->plt_section()->address() + gsym->plt_offset();
}

// The selector for powerpc object files.

template<int size, bool big_endian>
class Target_selector_powerpc : public Target_selector
{
public:
  Target_selector_powerpc()
    : Target_selector(elfcpp::EM_NONE, size, big_endian,
                      (size == 64 ?
                       (big_endian ? "elf64-powerpc" : "elf64-powerpcle") :
                       (big_endian ? "elf32-powerpc" : "elf32-powerpcle")))
  { }

  Target* do_recognize(int machine, int, int)
  {
    switch (size)
      {
      case 64:
        if (machine != elfcpp::EM_PPC64)
          return NULL;
        break;

      case 32:
        if (machine != elfcpp::EM_PPC)
          return NULL;
        break;

      default:
        return NULL;
      }

    return this->instantiate_target();
  }

  Target* do_instantiate_target()
  { return new Target_powerpc<size, big_endian>(); }
};

Target_selector_powerpc<32, true> target_selector_ppc32;
Target_selector_powerpc<32, false> target_selector_ppc32le;
Target_selector_powerpc<64, true> target_selector_ppc64;
Target_selector_powerpc<64, false> target_selector_ppc64le;

} // End anonymous namespace.