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// plugin.h -- plugin manager for gold      -*- C++ -*-

// Copyright 2008, 2009 Free Software Foundation, Inc.

// Written by Cary Coutant <ccoutant@google.com>.

// This file is part of gold.

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

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

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

// (at your option) any later version.

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

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

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

// GNU General Public License for more details.

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

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

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

// MA 02110-1301, USA.

#ifndef GOLD_PLUGIN_H

#define GOLD_PLUGIN_H

#include <list>

#include <string>

#include "object.h"

#include "plugin-api.h"

#include "workqueue.h"

namespace gold

{

class General_options;

class Input_file;

class Input_objects;

class Symbol_table;

class Layout;

class Dirsearch;

class Mapfile;

class Task_token;

class Pluginobj;

// This class represents a single plugin library.

class Plugin

{

 public:

  Plugin(const char* filename)

    : handle_(NULL),

      filename_(filename),

      args_(),

      claim_file_handler_(NULL),

      all_symbols_read_handler_(NULL),

      cleanup_handler_(NULL)

  { }

  ~Plugin()

  { }

  // Load the library and call its entry point.

  void

  load();

  // Call the claim-file handler.

  bool

  claim_file(struct ld_plugin_input_file *plugin_input_file);

  // Call the all-symbols-read handler.

  void

  all_symbols_read();

  // Call the cleanup handler.

  void

  cleanup();

  // Register a claim-file handler.

  void

  set_claim_file_handler(ld_plugin_claim_file_handler handler)

  { this->claim_file_handler_ = handler; }

  // Register an all-symbols-read handler.

  void

  set_all_symbols_read_handler(ld_plugin_all_symbols_read_handler handler)

  { this->all_symbols_read_handler_ = handler; }

  // Register a claim-file handler.

  void

  set_cleanup_handler(ld_plugin_cleanup_handler handler)

  { this->cleanup_handler_ = handler; }

  // Add an argument

  void

  add_option(const char *arg)

  {

    this->args_.push_back(arg);

  }

 private:

  Plugin(const Plugin&);

  Plugin& operator=(const Plugin&);

  // The shared library handle returned by dlopen.

  void* handle_;

  // The argument string given to --plugin.

  std::string filename_;

  // The list of argument string given to --plugin-opt.

  std::vector<std::string> args_;

  // The plugin's event handlers.

  ld_plugin_claim_file_handler claim_file_handler_;

  ld_plugin_all_symbols_read_handler all_symbols_read_handler_;

  ld_plugin_cleanup_handler cleanup_handler_;

};

// A manager class for plugins.

class Plugin_manager

{

 public:

  Plugin_manager(const General_options& options)

    : plugins_(), objects_(), deferred_layout_objects_(), input_file_(NULL),

      plugin_input_file_(), in_replacement_phase_(false), cleanup_done_(false),

      options_(options), workqueue_(NULL), task_(NULL), input_objects_(NULL),

      symtab_(NULL), layout_(NULL), dirpath_(NULL), mapfile_(NULL),

      this_blocker_(NULL)

  { this->current_ = plugins_.end(); }

  ~Plugin_manager();

  // Add a plugin library.

  void

  add_plugin(const char* filename)

  { this->plugins_.push_back(new Plugin(filename)); }

  // Add an argument to the current plugin.

  void

  add_plugin_option(const char* opt)

  {

    Plugin* last = this->plugins_.back();

    last->add_option(opt);

  }

  // Load all plugin libraries.

  void

  load_plugins();

  // Call the plugin claim-file handlers in turn to see if any claim the file.

  Pluginobj*

  claim_file(Input_file *input_file, off_t offset, off_t filesize);

  // Call the all-symbols-read handlers.

  void

  all_symbols_read(Workqueue* workqueue, Task* task,

                   Input_objects* input_objects, Symbol_table* symtab,

                   Layout* layout, Dirsearch* dirpath, Mapfile* mapfile,

                   Task_token** last_blocker);

  // Run deferred layout.

  void

  layout_deferred_objects();

  // Call the cleanup handlers.

  void

  cleanup();

  // Register a claim-file handler.

  void

  set_claim_file_handler(ld_plugin_claim_file_handler handler)

  {

    gold_assert(this->current_ != plugins_.end());

    (*this->current_)->set_claim_file_handler(handler);

  }

  // Register an all-symbols-read handler.

  void

  set_all_symbols_read_handler(ld_plugin_all_symbols_read_handler handler)

  {

    gold_assert(this->current_ != plugins_.end());

    (*this->current_)->set_all_symbols_read_handler(handler);

  }

  // Register a claim-file handler.

  void

  set_cleanup_handler(ld_plugin_cleanup_handler handler)

  {

    gold_assert(this->current_ != plugins_.end());

    (*this->current_)->set_cleanup_handler(handler);

  }

  // Make a new Pluginobj object.  This is called when the plugin calls

  // the add_symbols API.

  Pluginobj*

  make_plugin_object(unsigned int handle);

  // Return the Pluginobj associated with the given HANDLE.

  Pluginobj*

  object(unsigned int handle) const

  {

    if (handle >= this->objects_.size())

      return NULL;

    return this->objects_[handle];

  }

  // Return TRUE if any input files have been claimed by a plugin

  // and we are still in the initial input phase.

  bool

  should_defer_layout() const

  { return !this->objects_.empty() && !this->in_replacement_phase_; }

  // Add a regular object to the deferred layout list.  These are

  // objects whose layout has been deferred until after the

  // replacement files have arrived.

  void

  add_deferred_layout_object(Relobj* obj)

  { this->deferred_layout_objects_.push_back(obj); }

  // Get input file information with an open (possibly re-opened)

  // file descriptor.

  ld_plugin_status

  get_input_file(unsigned int handle, struct ld_plugin_input_file *file);

  // Release an input file.

  ld_plugin_status

  release_input_file(unsigned int handle);

  // Add a new input file.

  ld_plugin_status

  add_input_file(char *pathname, bool is_lib);

  // Return TRUE if we are in the replacement phase.

  bool

  in_replacement_phase() const

  { return this->in_replacement_phase_; }

 private:

  Plugin_manager(const Plugin_manager&);

  Plugin_manager& operator=(const Plugin_manager&);

  typedef std::list<Plugin*> Plugin_list;

  typedef std::vector<Pluginobj*> Object_list;

  typedef std::vector<Relobj*> Deferred_layout_list;

  // The list of plugin libraries.

  Plugin_list plugins_;

  // A pointer to the current plugin.  Used while loading plugins.

  Plugin_list::iterator current_;

  // The list of plugin objects.  The index of an item in this list

  // serves as the "handle" that we pass to the plugins.

  Object_list objects_;

  // The list of regular objects whose layout has been deferred.

  Deferred_layout_list deferred_layout_objects_;

  // The file currently up for claim by the plugins.

  Input_file* input_file_;

  struct ld_plugin_input_file plugin_input_file_;

  // TRUE after the all symbols read event; indicates that we are

  // processing replacement files whose symbols should replace the

  // placeholder symbols from the Pluginobj objects.

  bool in_replacement_phase_;

  // TRUE if the cleanup handlers have been called.

  bool cleanup_done_;

  const General_options& options_;

  Workqueue* workqueue_;

  Task* task_;

  Input_objects* input_objects_;

  Symbol_table* symtab_;

  Layout* layout_;

  Dirsearch* dirpath_;

  Mapfile* mapfile_;

  Task_token* this_blocker_;

};

// An object file claimed by a plugin.  This is an abstract base class.

// The implementation is the template class Sized_pluginobj.

class Pluginobj : public Object

{

 public:

  typedef std::vector<Symbol*> Symbols;

  Pluginobj(const std::string& name, Input_file* input_file, off_t offset,

            off_t filesize);

  // Fill in the symbol resolution status for the given plugin symbols.

  ld_plugin_status

  get_symbol_resolution_info(int nsyms, ld_plugin_symbol* syms) const;

  // Store the incoming symbols from the plugin for later processing.

  void

  store_incoming_symbols(int nsyms, const struct ld_plugin_symbol* syms)

  {

    this->nsyms_ = nsyms;

    this->syms_ = syms;

  }

  // Return TRUE if the comdat group with key COMDAT_KEY from this object

  // should be kept.

  bool

  include_comdat_group(std::string comdat_key, Layout* layout);

  // Return the filename.

  const std::string&

  filename() const

  { return this->input_file()->filename(); }

  // Return the file descriptor.

  int

  descriptor()

  { return this->input_file()->file().descriptor(); }

  // Return the size of the file or archive member.

  off_t

  filesize()

  { return this->filesize_; }

 protected:

  // Return TRUE if this is an object claimed by a plugin.

  virtual Pluginobj*

  do_pluginobj()

  { return this; }

  // The number of symbols provided by the plugin.

  int nsyms_;

  // The symbols provided by the plugin.

  const struct ld_plugin_symbol* syms_;

  // The entries in the symbol table for the external symbols.

  Symbols symbols_;

 private:

  // Size of the file (or archive member).

  off_t filesize_;

  // Map a comdat key symbol to a boolean indicating whether the comdat

  // group in this object with that key should be kept.

  typedef Unordered_map<std::string, bool> Comdat_map;

  Comdat_map comdat_map_;

};

// A plugin object, size-specific version.

template<int size, bool big_endian>

class Sized_pluginobj : public Pluginobj

{

 public:

  Sized_pluginobj(const std::string& name, Input_file* input_file,

                  off_t offset, off_t filesize);

  // Read the symbols.

  void

  do_read_symbols(Read_symbols_data*);

  // Lay out the input sections.

  void

  do_layout(Symbol_table*, Layout*, Read_symbols_data*);

  // Add the symbols to the symbol table.

  void

  do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*);

  // Get the size of a section.

  uint64_t

  do_section_size(unsigned int shndx);

  // Get the name of a section.

  std::string

  do_section_name(unsigned int shndx);

  // Return a view of the contents of a section.

  Object::Location

  do_section_contents(unsigned int shndx);

  // Return section flags.

  uint64_t

  do_section_flags(unsigned int shndx);

  // Return section entsize.

  uint64_t

  do_section_entsize(unsigned int shndx);

  // Return section address.

  uint64_t

  do_section_address(unsigned int shndx);

  // Return section type.

  unsigned int

  do_section_type(unsigned int shndx);

  // Return the section link field.

  unsigned int

  do_section_link(unsigned int shndx);

  // Return the section link field.

  unsigned int

  do_section_info(unsigned int shndx);

  // Return the section alignment.

  uint64_t

  do_section_addralign(unsigned int shndx);

  // Return the Xindex structure to use.

  Xindex*

  do_initialize_xindex();

  // Get symbol counts.

  void

  do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const;

  // Add placeholder symbols from a claimed file.

  ld_plugin_status

  add_symbols_from_plugin(int nsyms, const ld_plugin_symbol* syms);

 protected:

 private:

};

// This Task handles handles the "all symbols read" event hook.

// The plugin may add additional input files at this time, which must

// be queued for reading.

class Plugin_hook : public Task

{

 public:

  Plugin_hook(const General_options& options, Input_objects* input_objects,

              Symbol_table* symtab, Layout* layout, Dirsearch* dirpath,

              Mapfile* mapfile, Task_token* this_blocker,

              Task_token* next_blocker)

    : options_(options), input_objects_(input_objects), symtab_(symtab),

      layout_(layout), dirpath_(dirpath), mapfile_(mapfile),

      this_blocker_(this_blocker), next_blocker_(next_blocker)

  { }

  ~Plugin_hook();

  // The standard Task methods.

  Task_token*

  is_runnable();

  void

  locks(Task_locker*);

  void

  run(Workqueue*);

  std::string

  get_name() const

  { return "Plugin_hook"; }

 private:

  const General_options& options_;

  Input_objects* input_objects_;

  Symbol_table* symtab_;

  Layout* layout_;

  Dirsearch* dirpath_;

  Mapfile* mapfile_;

  Task_token* this_blocker_;

  Task_token* next_blocker_;

};

} // End namespace gold.

#endif // !defined(GOLD_PLUGIN_H)