Add upstream binutils-2.25 snapshot 4/4 2014

For MIPS -mmsa support

Change-Id: I08c4f002fa7b33dec85ed75956e6ab551bb03c96

1 files changed, 1037 insertions, 0 deletions

diff --git a/binutils-2.25/gold/target.h b/binutils-2.25/gold/target.h
new file mode 100644
index 0000000..415b7ed
--- /dev/null
+++ b/binutils-2.25/gold/target.h
@@ -0,0 +1,1037 @@
+// target.h -- target support for gold   -*- C++ -*-
+
+// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
+// 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.
+
+// The abstract class Target is the interface for target specific
+// support.  It defines abstract methods which each target must
+// implement.  Typically there will be one target per processor, but
+// in some cases it may be necessary to have subclasses.
+
+// For speed and consistency we want to use inline functions to handle
+// relocation processing.  So besides implementations of the abstract
+// methods, each target is expected to define a template
+// specialization of the relocation functions.
+
+#ifndef GOLD_TARGET_H
+#define GOLD_TARGET_H
+
+#include "elfcpp.h"
+#include "options.h"
+#include "parameters.h"
+#include "debug.h"
+
+namespace gold
+{
+
+class Object;
+class Relobj;
+template<int size, bool big_endian>
+class Sized_relobj;
+template<int size, bool big_endian>
+class Sized_relobj_file;
+class Relocatable_relocs;
+template<int size, bool big_endian>
+struct Relocate_info;
+class Reloc_symbol_changes;
+class Symbol;
+template<int size>
+class Sized_symbol;
+class Symbol_table;
+class Output_data;
+class Output_data_got_base;
+class Output_section;
+class Input_objects;
+class Task;
+struct Symbol_location;
+
+// The abstract class for target specific handling.
+
+class Target
+{
+ public:
+  virtual ~Target()
+  { }
+
+  // Return the bit size that this target implements.  This should
+  // return 32 or 64.
+  int
+  get_size() const
+  { return this->pti_->size; }
+
+  // Return whether this target is big-endian.
+  bool
+  is_big_endian() const
+  { return this->pti_->is_big_endian; }
+
+  // Machine code to store in e_machine field of ELF header.
+  elfcpp::EM
+  machine_code() const
+  { return this->pti_->machine_code; }
+
+  // Processor specific flags to store in e_flags field of ELF header.
+  elfcpp::Elf_Word
+  processor_specific_flags() const
+  { return this->processor_specific_flags_; }
+
+  // Whether processor specific flags are set at least once.
+  bool
+  are_processor_specific_flags_set() const
+  { return this->are_processor_specific_flags_set_; }
+
+  // Whether this target has a specific make_symbol function.
+  bool
+  has_make_symbol() const
+  { return this->pti_->has_make_symbol; }
+
+  // Whether this target has a specific resolve function.
+  bool
+  has_resolve() const
+  { return this->pti_->has_resolve; }
+
+  // Whether this target has a specific code fill function.
+  bool
+  has_code_fill() const
+  { return this->pti_->has_code_fill; }
+
+  // Return the default name of the dynamic linker.
+  const char*
+  dynamic_linker() const
+  { return this->pti_->dynamic_linker; }
+
+  // Return the default address to use for the text segment.
+  uint64_t
+  default_text_segment_address() const
+  { return this->pti_->default_text_segment_address; }
+
+  // Return the ABI specified page size.
+  uint64_t
+  abi_pagesize() const
+  {
+    if (parameters->options().max_page_size() > 0)
+      return parameters->options().max_page_size();
+    else
+      return this->pti_->abi_pagesize;
+  }
+
+  // Return the common page size used on actual systems.
+  uint64_t
+  common_pagesize() const
+  {
+    if (parameters->options().common_page_size() > 0)
+      return std::min(parameters->options().common_page_size(),
+		      this->abi_pagesize());
+    else
+      return std::min(this->pti_->common_pagesize,
+		      this->abi_pagesize());
+  }
+
+  // Return whether PF_X segments must contain nothing but the contents of
+  // SHF_EXECINSTR sections (no non-executable data, no headers).
+  bool
+  isolate_execinstr() const
+  { return this->pti_->isolate_execinstr; }
+
+  uint64_t
+  rosegment_gap() const
+  { return this->pti_->rosegment_gap; }
+
+  // If we see some object files with .note.GNU-stack sections, and
+  // some objects files without them, this returns whether we should
+  // consider the object files without them to imply that the stack
+  // should be executable.
+  bool
+  is_default_stack_executable() const
+  { return this->pti_->is_default_stack_executable; }
+
+  // Return a character which may appear as a prefix for a wrap
+  // symbol.  If this character appears, we strip it when checking for
+  // wrapping and add it back when forming the final symbol name.
+  // This should be '\0' if not special prefix is required, which is
+  // the normal case.
+  char
+  wrap_char() const
+  { return this->pti_->wrap_char; }
+
+  // Return the special section index which indicates a small common
+  // symbol.  This will return SHN_UNDEF if there are no small common
+  // symbols.
+  elfcpp::Elf_Half
+  small_common_shndx() const
+  { return this->pti_->small_common_shndx; }
+
+  // Return values to add to the section flags for the section holding
+  // small common symbols.
+  elfcpp::Elf_Xword
+  small_common_section_flags() const
+  {
+    gold_assert(this->pti_->small_common_shndx != elfcpp::SHN_UNDEF);
+    return this->pti_->small_common_section_flags;
+  }
+
+  // Return the special section index which indicates a large common
+  // symbol.  This will return SHN_UNDEF if there are no large common
+  // symbols.
+  elfcpp::Elf_Half
+  large_common_shndx() const
+  { return this->pti_->large_common_shndx; }
+
+  // Return values to add to the section flags for the section holding
+  // large common symbols.
+  elfcpp::Elf_Xword
+  large_common_section_flags() const
+  {
+    gold_assert(this->pti_->large_common_shndx != elfcpp::SHN_UNDEF);
+    return this->pti_->large_common_section_flags;
+  }
+
+  // This hook is called when an output section is created.
+  void
+  new_output_section(Output_section* os) const
+  { this->do_new_output_section(os); }
+
+  // This is called to tell the target to complete any sections it is
+  // handling.  After this all sections must have their final size.
+  void
+  finalize_sections(Layout* layout, const Input_objects* input_objects,
+		    Symbol_table* symtab)
+  { return this->do_finalize_sections(layout, input_objects, symtab); }
+
+  // Return the value to use for a global symbol which needs a special
+  // value in the dynamic symbol table.  This will only be called if
+  // the backend first calls symbol->set_needs_dynsym_value().
+  uint64_t
+  dynsym_value(const Symbol* sym) const
+  { return this->do_dynsym_value(sym); }
+
+  // Return a string to use to fill out a code section.  This is
+  // basically one or more NOPS which must fill out the specified
+  // length in bytes.
+  std::string
+  code_fill(section_size_type length) const
+  { return this->do_code_fill(length); }
+
+  // Return whether SYM is known to be defined by the ABI.  This is
+  // used to avoid inappropriate warnings about undefined symbols.
+  bool
+  is_defined_by_abi(const Symbol* sym) const
+  { return this->do_is_defined_by_abi(sym); }
+
+  // Adjust the output file header before it is written out.  VIEW
+  // points to the header in external form.  LEN is the length.
+  void
+  adjust_elf_header(unsigned char* view, int len)
+  { return this->do_adjust_elf_header(view, len); }
+
+  // Return address and size to plug into eh_frame FDEs associated with a PLT.
+  void
+  plt_fde_location(const Output_data* plt, unsigned char* oview,
+		   uint64_t* address, off_t* len) const
+  { return this->do_plt_fde_location(plt, oview, address, len); }
+
+  // Return whether NAME is a local label name.  This is used to implement the
+  // --discard-locals options.
+  bool
+  is_local_label_name(const char* name) const
+  { return this->do_is_local_label_name(name); }
+
+  // Get the symbol index to use for a target specific reloc.
+  unsigned int
+  reloc_symbol_index(void* arg, unsigned int type) const
+  { return this->do_reloc_symbol_index(arg, type); }
+
+  // Get the addend to use for a target specific reloc.
+  uint64_t
+  reloc_addend(void* arg, unsigned int type, uint64_t addend) const
+  { return this->do_reloc_addend(arg, type, addend); }
+
+  // Return the PLT address to use for a global symbol.
+  uint64_t
+  plt_address_for_global(const Symbol* sym) const
+  { return this->do_plt_address_for_global(sym); }
+
+  // Return the PLT address to use for a local symbol.
+  uint64_t
+  plt_address_for_local(const Relobj* object, unsigned int symndx) const
+  { return this->do_plt_address_for_local(object, symndx); }
+
+  // Return the offset to use for the GOT_INDX'th got entry which is
+  // for a local tls symbol specified by OBJECT, SYMNDX.
+  int64_t
+  tls_offset_for_local(const Relobj* object,
+		       unsigned int symndx,
+		       unsigned int got_indx) const
+  { return do_tls_offset_for_local(object, symndx, got_indx); }
+
+  // Return the offset to use for the GOT_INDX'th got entry which is
+  // for global tls symbol GSYM.
+  int64_t
+  tls_offset_for_global(Symbol* gsym, unsigned int got_indx) const
+  { return do_tls_offset_for_global(gsym, got_indx); }
+
+  // For targets that use function descriptors, if LOC is the location
+  // of a function, modify it to point at the function entry location.
+  void
+  function_location(Symbol_location* loc) const
+  { return do_function_location(loc); }
+
+  // Return whether this target can use relocation types to determine
+  // if a function's address is taken.
+  bool
+  can_check_for_function_pointers() const
+  { return this->do_can_check_for_function_pointers(); }
+
+  // Return whether a relocation to a merged section can be processed
+  // to retrieve the contents.
+  bool
+  can_icf_inline_merge_sections () const
+  { return this->pti_->can_icf_inline_merge_sections; }
+
+  // Whether a section called SECTION_NAME may have function pointers to
+  // sections not eligible for safe ICF folding.
+  virtual bool
+  section_may_have_icf_unsafe_pointers(const char* section_name) const
+  { return this->do_section_may_have_icf_unsafe_pointers(section_name); }
+
+  // Return the base to use for the PC value in an FDE when it is
+  // encoded using DW_EH_PE_datarel.  This does not appear to be
+  // documented anywhere, but it is target specific.  Any use of
+  // DW_EH_PE_datarel in gcc requires defining a special macro
+  // (ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX) to output the value.
+  uint64_t
+  ehframe_datarel_base() const
+  { return this->do_ehframe_datarel_base(); }
+
+  // Return true if a reference to SYM from a reloc of type R_TYPE
+  // means that the current function may call an object compiled
+  // without -fsplit-stack.  SYM is known to be defined in an object
+  // compiled without -fsplit-stack.
+  bool
+  is_call_to_non_split(const Symbol* sym, unsigned int r_type) const
+  { return this->do_is_call_to_non_split(sym, r_type); }
+
+  // A function starts at OFFSET in section SHNDX in OBJECT.  That
+  // function was compiled with -fsplit-stack, but it refers to a
+  // function which was compiled without -fsplit-stack.  VIEW is a
+  // modifiable view of the section; VIEW_SIZE is the size of the
+  // view.  The target has to adjust the function so that it allocates
+  // enough stack.
+  void
+  calls_non_split(Relobj* object, unsigned int shndx,
+		  section_offset_type fnoffset, section_size_type fnsize,
+		  unsigned char* view, section_size_type view_size,
+		  std::string* from, std::string* to) const
+  {
+    this->do_calls_non_split(object, shndx, fnoffset, fnsize, view, view_size,
+			     from, to);
+  }
+
+  // Make an ELF object.
+  template<int size, bool big_endian>
+  Object*
+  make_elf_object(const std::string& name, Input_file* input_file,
+		  off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr)
+  { return this->do_make_elf_object(name, input_file, offset, ehdr); }
+
+  // Make an output section.
+  Output_section*
+  make_output_section(const char* name, elfcpp::Elf_Word type,
+		      elfcpp::Elf_Xword flags)
+  { return this->do_make_output_section(name, type, flags); }
+
+  // Return true if target wants to perform relaxation.
+  bool
+  may_relax() const
+  {
+    // Run the dummy relaxation pass twice if relaxation debugging is enabled.
+    if (is_debugging_enabled(DEBUG_RELAXATION))
+      return true;
+
+     return this->do_may_relax();
+  }
+
+  // Perform a relaxation pass.  Return true if layout may be changed.
+  bool
+  relax(int pass, const Input_objects* input_objects, Symbol_table* symtab,
+	Layout* layout, const Task* task)
+  {
+    // Run the dummy relaxation pass twice if relaxation debugging is enabled.
+    if (is_debugging_enabled(DEBUG_RELAXATION))
+      return pass < 2;
+
+    return this->do_relax(pass, input_objects, symtab, layout, task);
+  }
+
+  // Return the target-specific name of attributes section.  This is
+  // NULL if a target does not use attributes section or if it uses
+  // the default section name ".gnu.attributes".
+  const char*
+  attributes_section() const
+  { return this->pti_->attributes_section; }
+
+  // Return the vendor name of vendor attributes.
+  const char*
+  attributes_vendor() const
+  { return this->pti_->attributes_vendor; }
+
+  // Whether a section called NAME is an attribute section.
+  bool
+  is_attributes_section(const char* name) const
+  {
+    return ((this->pti_->attributes_section != NULL
+	     && strcmp(name, this->pti_->attributes_section) == 0)
+	    || strcmp(name, ".gnu.attributes") == 0);
+  }
+
+  // Return a bit mask of argument types for attribute with TAG.
+  int
+  attribute_arg_type(int tag) const
+  { return this->do_attribute_arg_type(tag); }
+
+  // Return the attribute tag of the position NUM in the list of fixed
+  // attributes.  Normally there is no reordering and
+  // attributes_order(NUM) == NUM.
+  int
+  attributes_order(int num) const
+  { return this->do_attributes_order(num); }
+
+  // When a target is selected as the default target, we call this method,
+  // which may be used for expensive, target-specific initialization.
+  void
+  select_as_default_target()
+  { this->do_select_as_default_target(); }
+
+  // Return the value to store in the EI_OSABI field in the ELF
+  // header.
+  elfcpp::ELFOSABI
+  osabi() const
+  { return this->osabi_; }
+
+  // Set the value to store in the EI_OSABI field in the ELF header.
+  void
+  set_osabi(elfcpp::ELFOSABI osabi)
+  { this->osabi_ = osabi; }
+
+  // Define target-specific standard symbols.
+  void
+  define_standard_symbols(Symbol_table* symtab, Layout* layout)
+  { this->do_define_standard_symbols(symtab, layout); }
+
+  // Return the output section name to use given an input section
+  // name, or NULL if no target specific name mapping is required.
+  // Set *PLEN to the length of the name if returning non-NULL.
+  const char*
+  output_section_name(const Relobj* relobj,
+		      const char* name,
+		      size_t* plen) const
+  { return this->do_output_section_name(relobj, name, plen); }
+
+  // Add any special sections for this symbol to the gc work list.
+  void
+  gc_mark_symbol(Symbol_table* symtab, Symbol* sym) const
+  { this->do_gc_mark_symbol(symtab, sym); }
+
+  // Return the name of the entry point symbol.
+  const char*
+  entry_symbol_name() const
+  { return this->pti_->entry_symbol_name; }
+
+ protected:
+  // This struct holds the constant information for a child class.  We
+  // use a struct to avoid the overhead of virtual function calls for
+  // simple information.
+  struct Target_info
+  {
+    // Address size (32 or 64).
+    int size;
+    // Whether the target is big endian.
+    bool is_big_endian;
+    // The code to store in the e_machine field of the ELF header.
+    elfcpp::EM machine_code;
+    // Whether this target has a specific make_symbol function.
+    bool has_make_symbol;
+    // Whether this target has a specific resolve function.
+    bool has_resolve;
+    // Whether this target has a specific code fill function.
+    bool has_code_fill;
+    // Whether an object file with no .note.GNU-stack sections implies
+    // that the stack should be executable.
+    bool is_default_stack_executable;
+    // Whether a relocation to a merged section can be processed to
+    // retrieve the contents.
+    bool can_icf_inline_merge_sections;
+    // Prefix character to strip when checking for wrapping.
+    char wrap_char;
+    // The default dynamic linker name.
+    const char* dynamic_linker;
+    // The default text segment address.
+    uint64_t default_text_segment_address;
+    // The ABI specified page size.
+    uint64_t abi_pagesize;
+    // The common page size used by actual implementations.
+    uint64_t common_pagesize;
+    // Whether PF_X segments must contain nothing but the contents of
+    // SHF_EXECINSTR sections (no non-executable data, no headers).
+    bool isolate_execinstr;
+    // If nonzero, distance from the text segment to the read-only segment.
+    uint64_t rosegment_gap;
+    // The special section index for small common symbols; SHN_UNDEF
+    // if none.
+    elfcpp::Elf_Half small_common_shndx;
+    // The special section index for large common symbols; SHN_UNDEF
+    // if none.
+    elfcpp::Elf_Half large_common_shndx;
+    // Section flags for small common section.
+    elfcpp::Elf_Xword small_common_section_flags;
+    // Section flags for large common section.
+    elfcpp::Elf_Xword large_common_section_flags;
+    // Name of attributes section if it is not ".gnu.attributes".
+    const char* attributes_section;
+    // Vendor name of vendor attributes.
+    const char* attributes_vendor;
+    // Name of the main entry point to the program.
+    const char* entry_symbol_name;
+  };
+
+  Target(const Target_info* pti)
+    : pti_(pti), processor_specific_flags_(0),
+      are_processor_specific_flags_set_(false), osabi_(elfcpp::ELFOSABI_NONE)
+  { }
+
+  // Virtual function which may be implemented by the child class.
+  virtual void
+  do_new_output_section(Output_section*) const
+  { }
+
+  // Virtual function which may be implemented by the child class.
+  virtual void
+  do_finalize_sections(Layout*, const Input_objects*, Symbol_table*)
+  { }
+
+  // Virtual function which may be implemented by the child class.
+  virtual uint64_t
+  do_dynsym_value(const Symbol*) const
+  { gold_unreachable(); }
+
+  // Virtual function which must be implemented by the child class if
+  // needed.
+  virtual std::string
+  do_code_fill(section_size_type) const
+  { gold_unreachable(); }
+
+  // Virtual function which may be implemented by the child class.
+  virtual bool
+  do_is_defined_by_abi(const Symbol*) const
+  { return false; }
+
+  // Adjust the output file header before it is written out.  VIEW
+  // points to the header in external form.  LEN is the length, and
+  // will be one of the values of elfcpp::Elf_sizes<size>::ehdr_size.
+  // By default, we set the EI_OSABI field if requested (in
+  // Sized_target).
+  virtual void
+  do_adjust_elf_header(unsigned char*, int) = 0;
+
+  // Return address and size to plug into eh_frame FDEs associated with a PLT.
+  virtual void
+  do_plt_fde_location(const Output_data* plt, unsigned char* oview,
+		      uint64_t* address, off_t* len) const;
+
+  // Virtual function which may be overridden by the child class.
+  virtual bool
+  do_is_local_label_name(const char*) const;
+
+  // Virtual function that must be overridden by a target which uses
+  // target specific relocations.
+  virtual unsigned int
+  do_reloc_symbol_index(void*, unsigned int) const
+  { gold_unreachable(); }
+
+  // Virtual function that must be overridden by a target which uses
+  // target specific relocations.
+  virtual uint64_t
+  do_reloc_addend(void*, unsigned int, uint64_t) const
+  { gold_unreachable(); }
+
+  // Virtual functions that must be overridden by a target that uses
+  // STT_GNU_IFUNC symbols.
+  virtual uint64_t
+  do_plt_address_for_global(const Symbol*) const
+  { gold_unreachable(); }
+
+  virtual uint64_t
+  do_plt_address_for_local(const Relobj*, unsigned int) const
+  { gold_unreachable(); }
+
+  virtual int64_t
+  do_tls_offset_for_local(const Relobj*, unsigned int, unsigned int) const
+  { gold_unreachable(); }
+
+  virtual int64_t
+  do_tls_offset_for_global(Symbol*, unsigned int) const
+  { gold_unreachable(); }
+
+  virtual void
+  do_function_location(Symbol_location*) const = 0;
+
+  // Virtual function which may be overriden by the child class.
+  virtual bool
+  do_can_check_for_function_pointers() const
+  { return false; }
+
+  // Virtual function which may be overridden by the child class.  We
+  // recognize some default sections for which we don't care whether
+  // they have function pointers.
+  virtual bool
+  do_section_may_have_icf_unsafe_pointers(const char* section_name) const
+  {
+    // We recognize sections for normal vtables, construction vtables and
+    // EH frames.
+    return (!is_prefix_of(".rodata._ZTV", section_name)
+	    && !is_prefix_of(".data.rel.ro._ZTV", section_name)
+	    && !is_prefix_of(".rodata._ZTC", section_name)
+	    && !is_prefix_of(".data.rel.ro._ZTC", section_name)
+	    && !is_prefix_of(".eh_frame", section_name));
+  }
+
+  virtual uint64_t
+  do_ehframe_datarel_base() const
+  { gold_unreachable(); }
+
+  // Virtual function which may be overridden by the child class.  The
+  // default implementation is that any function not defined by the
+  // ABI is a call to a non-split function.
+  virtual bool
+  do_is_call_to_non_split(const Symbol* sym, unsigned int) const;
+
+  // Virtual function which may be overridden by the child class.
+  virtual void
+  do_calls_non_split(Relobj* object, unsigned int, section_offset_type,
+		     section_size_type, unsigned char*, section_size_type,
+		     std::string*, std::string*) const;
+
+  // make_elf_object hooks.  There are four versions of these for
+  // different address sizes and endianness.
+
+  // Set processor specific flags.
+  void
+  set_processor_specific_flags(elfcpp::Elf_Word flags)
+  {
+    this->processor_specific_flags_ = flags;
+    this->are_processor_specific_flags_set_ = true;
+  }
+
+#ifdef HAVE_TARGET_32_LITTLE
+  // Virtual functions which may be overridden by the child class.
+  virtual Object*
+  do_make_elf_object(const std::string&, Input_file*, off_t,
+		     const elfcpp::Ehdr<32, false>&);
+#endif
+
+#ifdef HAVE_TARGET_32_BIG
+  // Virtual functions which may be overridden by the child class.
+  virtual Object*
+  do_make_elf_object(const std::string&, Input_file*, off_t,
+		     const elfcpp::Ehdr<32, true>&);
+#endif
+
+#ifdef HAVE_TARGET_64_LITTLE
+  // Virtual functions which may be overridden by the child class.
+  virtual Object*
+  do_make_elf_object(const std::string&, Input_file*, off_t,
+		     const elfcpp::Ehdr<64, false>& ehdr);
+#endif
+
+#ifdef HAVE_TARGET_64_BIG
+  // Virtual functions which may be overridden by the child class.
+  virtual Object*
+  do_make_elf_object(const std::string& name, Input_file* input_file,
+		     off_t offset, const elfcpp::Ehdr<64, true>& ehdr);
+#endif
+
+  // Virtual functions which may be overridden by the child class.
+  virtual Output_section*
+  do_make_output_section(const char* name, elfcpp::Elf_Word type,
+			 elfcpp::Elf_Xword flags);
+
+  // Virtual function which may be overridden by the child class.
+  virtual bool
+  do_may_relax() const
+  { return parameters->options().relax(); }
+
+  // Virtual function which may be overridden by the child class.
+  virtual bool
+  do_relax(int, const Input_objects*, Symbol_table*, Layout*, const Task*)
+  { return false; }
+
+  // A function for targets to call.  Return whether BYTES/LEN matches
+  // VIEW/VIEW_SIZE at OFFSET.
+  bool
+  match_view(const unsigned char* view, section_size_type view_size,
+	     section_offset_type offset, const char* bytes, size_t len) const;
+
+  // Set the contents of a VIEW/VIEW_SIZE to nops starting at OFFSET
+  // for LEN bytes.
+  void
+  set_view_to_nop(unsigned char* view, section_size_type view_size,
+		  section_offset_type offset, size_t len) const;
+
+  // This must be overridden by the child class if it has target-specific
+  // attributes subsection in the attribute section.
+  virtual int
+  do_attribute_arg_type(int) const
+  { gold_unreachable(); }
+
+  // This may be overridden by the child class.
+  virtual int
+  do_attributes_order(int num) const
+  { return num; }
+
+  // This may be overridden by the child class.
+  virtual void
+  do_select_as_default_target()
+  { }
+
+  // This may be overridden by the child class.
+  virtual void
+  do_define_standard_symbols(Symbol_table*, Layout*)
+  { }
+
+  // This may be overridden by the child class.
+  virtual const char*
+  do_output_section_name(const Relobj*, const char*, size_t*) const
+  { return NULL; }
+
+  // This may be overridden by the child class.
+  virtual void
+  do_gc_mark_symbol(Symbol_table*, Symbol*) const
+  { }
+
+ private:
+  // The implementations of the four do_make_elf_object virtual functions are
+  // almost identical except for their sizes and endianness.  We use a template.
+  // for their implementations.
+  template<int size, bool big_endian>
+  inline Object*
+  do_make_elf_object_implementation(const std::string&, Input_file*, off_t,
+				    const elfcpp::Ehdr<size, big_endian>&);
+
+  Target(const Target&);
+  Target& operator=(const Target&);
+
+  // The target information.
+  const Target_info* pti_;
+  // Processor-specific flags.
+  elfcpp::Elf_Word processor_specific_flags_;
+  // Whether the processor-specific flags are set at least once.
+  bool are_processor_specific_flags_set_;
+  // If not ELFOSABI_NONE, the value to put in the EI_OSABI field of
+  // the ELF header.  This is handled at this level because it is
+  // OS-specific rather than processor-specific.
+  elfcpp::ELFOSABI osabi_;
+};
+
+// The abstract class for a specific size and endianness of target.
+// Each actual target implementation class should derive from an
+// instantiation of Sized_target.
+
+template<int size, bool big_endian>
+class Sized_target : public Target
+{
+ public:
+  // Make a new symbol table entry for the target.  This should be
+  // overridden by a target which needs additional information in the
+  // symbol table.  This will only be called if has_make_symbol()
+  // returns true.
+  virtual Sized_symbol<size>*
+  make_symbol() const
+  { gold_unreachable(); }
+
+  // Resolve a symbol for the target.  This should be overridden by a
+  // target which needs to take special action.  TO is the
+  // pre-existing symbol.  SYM is the new symbol, seen in OBJECT.
+  // VERSION is the version of SYM.  This will only be called if
+  // has_resolve() returns true.
+  virtual void
+  resolve(Symbol*, const elfcpp::Sym<size, big_endian>&, Object*,
+	  const char*)
+  { gold_unreachable(); }
+
+  // Process the relocs for a section, and record information of the
+  // mapping from source to destination sections. This mapping is later
+  // used to determine unreferenced garbage sections. This procedure is
+  // only called during garbage collection.
+  virtual void
+  gc_process_relocs(Symbol_table* symtab,
+		    Layout* layout,
+		    Sized_relobj_file<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) = 0;
+
+  // Scan the relocs for a section, and record any information
+  // required for the symbol.  SYMTAB is the symbol table.  OBJECT is
+  // the object in which the section appears.  DATA_SHNDX is the
+  // section index that these relocs apply to.  SH_TYPE is the type of
+  // the relocation section, SHT_REL or SHT_RELA.  PRELOCS points to
+  // the relocation data.  RELOC_COUNT is the number of relocs.
+  // LOCAL_SYMBOL_COUNT is the number of local symbols.
+  // OUTPUT_SECTION is the output section.
+  // NEEDS_SPECIAL_OFFSET_HANDLING is true if offsets to the output
+  // sections are not mapped as usual.  PLOCAL_SYMBOLS points to the
+  // local symbol data from OBJECT.  GLOBAL_SYMBOLS is the array of
+  // pointers to the global symbol table from OBJECT.
+  virtual void
+  scan_relocs(Symbol_table* symtab,
+	      Layout* layout,
+	      Sized_relobj_file<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) = 0;
+
+  // Relocate section data.  SH_TYPE is the type of the relocation
+  // section, SHT_REL or SHT_RELA.  PRELOCS points to the relocation
+  // information.  RELOC_COUNT is the number of relocs.
+  // OUTPUT_SECTION is the output section.
+  // NEEDS_SPECIAL_OFFSET_HANDLING is true if offsets must be mapped
+  // to correspond to the output section.  VIEW is a view into the
+  // output file holding the section contents, VIEW_ADDRESS is the
+  // virtual address of the view, and VIEW_SIZE is the size of the
+  // view.  If NEEDS_SPECIAL_OFFSET_HANDLING is true, the VIEW_xx
+  // parameters refer to the complete output section data, not just
+  // the input section data.
+  virtual 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*) = 0;
+
+  // Scan the relocs during a relocatable link.  The parameters are
+  // like scan_relocs, with an additional Relocatable_relocs
+  // parameter, used to record the disposition of the relocs.
+  virtual void
+  scan_relocatable_relocs(Symbol_table* symtab,
+			  Layout* layout,
+			  Sized_relobj_file<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*) = 0;
+
+  // Emit relocations for a section during a relocatable link, and for
+  // --emit-relocs.  The parameters are like relocate_section, with
+  // additional parameters for the view of the output reloc section.
+  virtual void
+  relocate_relocs(const Relocate_info<size, big_endian>*,
+		  unsigned int sh_type,
+		  const unsigned char* prelocs,
+		  size_t reloc_count,
+		  Output_section* output_section,
+		  typename elfcpp::Elf_types<size>::Elf_Off
+                    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) = 0;
+
+  // Perform target-specific processing in a relocatable link.  This is
+  // only used if we use the relocation strategy RELOC_SPECIAL.
+  // RELINFO points to a Relocation_info structure. SH_TYPE is the relocation
+  // section type. PRELOC_IN points to the original relocation.  RELNUM is
+  // the index number of the relocation in the relocation section.
+  // OUTPUT_SECTION is the output section to which the relocation is applied.
+  // OFFSET_IN_OUTPUT_SECTION is the offset of the relocation input section
+  // within the output section.  VIEW points to the output view of the
+  // output section.  VIEW_ADDRESS is output address of the view.  VIEW_SIZE
+  // is the size of the output view and PRELOC_OUT points to the new
+  // relocation in the output object.
+  //
+  // A target only needs to override this if the generic code in
+  // target-reloc.h cannot handle some relocation types.
+
+  virtual void
+  relocate_special_relocatable(const Relocate_info<size, big_endian>*
+				/*relinfo */,
+			       unsigned int /* sh_type */,
+			       const unsigned char* /* preloc_in */,
+			       size_t /* relnum */,
+			       Output_section* /* output_section */,
+			       typename elfcpp::Elf_types<size>::Elf_Off
+                                 /* offset_in_output_section */,
+			       unsigned char* /* view */,
+			       typename elfcpp::Elf_types<size>::Elf_Addr
+				 /* view_address */,
+			       section_size_type /* view_size */,
+			       unsigned char* /* preloc_out*/)
+  { gold_unreachable(); }
+
+  // Return the number of entries in the GOT.  This is only used for
+  // laying out the incremental link info sections.  A target needs
+  // to implement this to support incremental linking.
+
+  virtual unsigned int
+  got_entry_count() const
+  { gold_unreachable(); }
+
+  // Return the number of entries in the PLT.  This is only used for
+  // laying out the incremental link info sections.  A target needs
+  // to implement this to support incremental linking.
+
+  virtual unsigned int
+  plt_entry_count() const
+  { gold_unreachable(); }
+
+  // Return the offset of the first non-reserved PLT entry.  This is
+  // only used for laying out the incremental link info sections.
+  // A target needs to implement this to support incremental linking.
+
+  virtual unsigned int
+  first_plt_entry_offset() const
+  { gold_unreachable(); }
+
+  // Return the size of each PLT entry.  This is only used for
+  // laying out the incremental link info sections.  A target needs
+  // to implement this to support incremental linking.
+
+  virtual unsigned int
+  plt_entry_size() const
+  { gold_unreachable(); }
+
+  // Create the GOT and PLT sections for an incremental update.
+  // A target needs to implement this to support incremental linking.
+
+  virtual Output_data_got_base*
+  init_got_plt_for_update(Symbol_table*,
+			  Layout*,
+			  unsigned int /* got_count */,
+			  unsigned int /* plt_count */)
+  { gold_unreachable(); }
+
+  // Reserve a GOT entry for a local symbol, and regenerate any
+  // necessary dynamic relocations.
+  virtual void
+  reserve_local_got_entry(unsigned int /* got_index */,
+			  Sized_relobj<size, big_endian>* /* obj */,
+			  unsigned int /* r_sym */,
+			  unsigned int /* got_type */)
+  { gold_unreachable(); }
+
+  // Reserve a GOT entry for a global symbol, and regenerate any
+  // necessary dynamic relocations.
+  virtual void
+  reserve_global_got_entry(unsigned int /* got_index */, Symbol* /* gsym */,
+			   unsigned int /* got_type */)
+  { gold_unreachable(); }
+
+  // Register an existing PLT entry for a global symbol.
+  // A target needs to implement this to support incremental linking.
+
+  virtual void
+  register_global_plt_entry(Symbol_table*, Layout*,
+			    unsigned int /* plt_index */,
+			    Symbol*)
+  { gold_unreachable(); }
+
+  // Force a COPY relocation for a given symbol.
+  // A target needs to implement this to support incremental linking.
+
+  virtual void
+  emit_copy_reloc(Symbol_table*, Symbol*, Output_section*, off_t)
+  { gold_unreachable(); }
+
+  // Apply an incremental relocation.
+
+  virtual void
+  apply_relocation(const Relocate_info<size, big_endian>* /* relinfo */,
+		   typename elfcpp::Elf_types<size>::Elf_Addr /* r_offset */,
+		   unsigned int /* r_type */,
+		   typename elfcpp::Elf_types<size>::Elf_Swxword /* r_addend */,
+		   const Symbol* /* gsym */,
+		   unsigned char* /* view */,
+		   typename elfcpp::Elf_types<size>::Elf_Addr /* address */,
+		   section_size_type /* view_size */)
+  { gold_unreachable(); }
+
+  // Handle target specific gc actions when adding a gc reference from
+  // SRC_OBJ, SRC_SHNDX to a location specified by DST_OBJ, DST_SHNDX
+  // and DST_OFF.
+  void
+  gc_add_reference(Symbol_table* symtab,
+		   Object* src_obj,
+		   unsigned int src_shndx,
+		   Object* dst_obj,
+		   unsigned int dst_shndx,
+		   typename elfcpp::Elf_types<size>::Elf_Addr dst_off) const
+  {
+    this->do_gc_add_reference(symtab, src_obj, src_shndx,
+			      dst_obj, dst_shndx, dst_off);
+  }
+
+ protected:
+  Sized_target(const Target::Target_info* pti)
+    : Target(pti)
+  {
+    gold_assert(pti->size == size);
+    gold_assert(pti->is_big_endian ? big_endian : !big_endian);
+  }
+
+  // Set the EI_OSABI field if requested.
+  virtual void
+  do_adjust_elf_header(unsigned char*, int);
+
+  // Handle target specific gc actions when adding a gc reference.
+  virtual void
+  do_gc_add_reference(Symbol_table*, Object*, unsigned int,
+		      Object*, unsigned int,
+		      typename elfcpp::Elf_types<size>::Elf_Addr) const
+  { }
+
+  virtual void
+  do_function_location(Symbol_location*) const
+  { }
+};
+
+} // End namespace gold.
+
+#endif // !defined(GOLD_TARGET_H)