readsyms.h

// readsyms.h -- read input file symbols for gold   -*- C++ -*-

// Copyright (C) 2006-2018 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.

// This file is part of gold.

// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
// MA 02110-1301, USA.

#ifndef GOLD_READSYMS_H
#define GOLD_READSYMS_H

#include <vector>

#include "workqueue.h"
#include "object.h"
#include "incremental.h"

namespace gold
{

class Input_objects;
class Symbol_table;
class Input_group;
class Archive;
class Finish_group;

// This Task is responsible for reading the symbols from an input
// file.  This also includes reading the relocations so that we can
// check for any that require a PLT and/or a GOT.  After the data has
// been read, this queues up another task to actually add the symbols
// to the symbol table.  The tasks are separated because the file
// reading can occur in parallel but adding the symbols must be done
// in the order of the input files.

class Read_symbols : public Task
{
 public:
  // DIRPATH is the list of directories to search for libraries.
  // INPUT is the file to read.  INPUT_GROUP is not NULL if we are in
  // the middle of an input group.  THIS_BLOCKER is used to prevent
  // the associated Add_symbols task from running before the previous
  // one has completed; it will be NULL for the first task.
  // NEXT_BLOCKER is used to block the next input file from adding
  // symbols.
  Read_symbols(Input_objects* input_objects, Symbol_table* symtab,
	       Layout* layout, Dirsearch* dirpath, int dirindex,
	       Mapfile* mapfile, const Input_argument* input_argument,
	       Input_group* input_group, Archive_member* member,
               Task_token* this_blocker, Task_token* next_blocker)
    : input_objects_(input_objects), symtab_(symtab), layout_(layout),
      dirpath_(dirpath), dirindex_(dirindex), mapfile_(mapfile),
      input_argument_(input_argument), input_group_(input_group),
      member_(member), this_blocker_(this_blocker),
      next_blocker_(next_blocker)
  { }

  ~Read_symbols();

  // If appropriate, issue a warning about skipping an incompatible
  // object.
  static void
  incompatible_warning(const Input_argument*, const Input_file*);

  // Requeue a Read_symbols task to search for the next object with
  // the same name.
  static void
  requeue(Workqueue*, Input_objects*, Symbol_table*, Layout*, Dirsearch*,
	  int dirindex, Mapfile*, const Input_argument*, Input_group*,
	  Task_token* next_blocker);

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const;

 private:
  // Handle an archive group.
  void
  do_group(Workqueue*);

  // Handle --start-lib ... --end-lib
  bool
  do_lib_group(Workqueue*);

  // Handle --whole-archive --start-lib ... --end-lib --no-whole-archive
  bool
  do_whole_lib_group(Workqueue*);

  // Open and identify the file.
  bool
  do_read_symbols(Workqueue*);

  Input_objects* input_objects_;
  Symbol_table* symtab_;
  Layout* layout_;
  Dirsearch* dirpath_;
  int dirindex_;
  Mapfile* mapfile_;
  const Input_argument* input_argument_;
  Input_group* input_group_;
  Archive_member* member_;
  Task_token* this_blocker_;
  Task_token* next_blocker_;
};

// This Task handles adding the symbols to the symbol table.  These
// tasks must be run in the same order as the arguments appear on the
// command line.

class Add_symbols : public Task
{
 public:
  // THIS_BLOCKER is used to prevent this task from running before the
  // one for the previous input file.  NEXT_BLOCKER is used to prevent
  // the next task from running.
  Add_symbols(Input_objects* input_objects, Symbol_table* symtab,
	      Layout* layout, Dirsearch* /*dirpath*/, int /*dirindex*/,
	      Mapfile* /*mapfile*/, const Input_argument* input_argument,
	      Object* object, Incremental_library* library,
	      Read_symbols_data* sd, Task_token* this_blocker,
	      Task_token* next_blocker)
    : input_objects_(input_objects), symtab_(symtab), layout_(layout),
      input_argument_(input_argument), object_(object), library_(library),
      sd_(sd), this_blocker_(this_blocker), next_blocker_(next_blocker)
  { }

  ~Add_symbols();

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const
  { return "Add_symbols " + this->object_->name(); }

private:
  Input_objects* input_objects_;
  Symbol_table* symtab_;
  Layout* layout_;
  const Input_argument* input_argument_;
  Object* object_;
  Incremental_library* library_;
  Read_symbols_data* sd_;
  Task_token* this_blocker_;
  Task_token* next_blocker_;
};

// This Task is responsible for reading the symbols from an archive
// member that has changed since the last incremental link.

class Read_member : public Task
{
 public:
  // INPUT is the file to read.  INPUT_GROUP is not NULL if we are in
  // the middle of an input group.  THIS_BLOCKER is used to prevent
  // the associated Add_symbols task from running before the previous
  // one has completed; it will be NULL for the first task.
  // NEXT_BLOCKER is used to block the next input file from adding
  // symbols.
  Read_member(Input_objects* /*input_objects*/, Symbol_table* /*symtab*/,
	      Layout* /*layout*/, Mapfile* /*mapfile*/,
	      const Incremental_binary::Input_reader* input_reader,
              Task_token* this_blocker, Task_token* next_blocker)
    : input_reader_(input_reader),
      this_blocker_(this_blocker), next_blocker_(next_blocker)
  { }

  ~Read_member();

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const
  {
    return (std::string("Read_member ") + this->input_reader_->filename());
  }

 private:
  const Incremental_binary::Input_reader* input_reader_;
  Task_token* this_blocker_;
  Task_token* next_blocker_;
};

// This Task is responsible for processing an input script file that has
// not changed since the last incremental link.

class Check_script : public Task
{
 public:
  Check_script(Layout* layout, Incremental_binary* ibase,
	       unsigned int input_file_index,
	       const Incremental_binary::Input_reader* input_reader,
	       Task_token* this_blocker, Task_token* next_blocker)
    : layout_(layout), ibase_(ibase), input_file_index_(input_file_index),
      input_reader_(input_reader), this_blocker_(this_blocker),
      next_blocker_(next_blocker)
  {
    this->filename_ = std::string(this->input_reader_->filename());
  }

  ~Check_script();

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const
  {
    return (std::string("Check_script ") + this->input_reader_->filename());
  }

 private:
  std::string filename_;
  Layout* layout_;
  Incremental_binary* ibase_;
  unsigned int input_file_index_;
  const Incremental_binary::Input_reader* input_reader_;
  Task_token* this_blocker_;
  Task_token* next_blocker_;
};

// This Task is responsible for processing an archive library that has
// not changed since the last incremental link.

class Check_library : public Task
{
 public:
  Check_library(Symbol_table* /*symtab*/, Layout* layout,
		Incremental_binary* ibase,
		unsigned int input_file_index,
		const Incremental_binary::Input_reader* input_reader,
		Task_token* this_blocker, Task_token* next_blocker)
    : layout_(layout), ibase_(ibase),
      input_file_index_(input_file_index), input_reader_(input_reader),
      this_blocker_(this_blocker), next_blocker_(next_blocker)
  { }

  ~Check_library();

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const
  {
    return (std::string("Check_library ") + this->input_reader_->filename());
  }

 private:
  Layout* layout_;
  Incremental_binary* ibase_;
  unsigned int input_file_index_;
  const Incremental_binary::Input_reader* input_reader_;
  Task_token* this_blocker_;
  Task_token* next_blocker_;
};

// This class is used to track the archives in a group.

class Input_group
{
 public:
  typedef std::vector<Archive*> Archives;
  typedef Archives::const_iterator const_iterator;

  Input_group()
    : archives_()
  { }

  ~Input_group();

  // Add an archive to the group.
  void
  add_archive(Archive* arch)
  { this->archives_.push_back(arch); }

  // Loop over the archives in the group.

  const_iterator
  begin() const
  { return this->archives_.begin(); }

  const_iterator
  end() const
  { return this->archives_.end(); }

 private:
  Archives archives_;
};

// This class starts the handling of a group.  It exists only to pick
// up the number of undefined symbols at that point, so that we only
// run back through the group if we saw a new undefined symbol.

class Start_group : public Task
{
 public:
  Start_group(Symbol_table* symtab, Finish_group* finish_group,
	      Task_token* this_blocker, Task_token* next_blocker)
    : symtab_(symtab), finish_group_(finish_group),
      this_blocker_(this_blocker), next_blocker_(next_blocker)
  { }

  ~Start_group();

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const
  { return "Start_group"; }

 private:
  Symbol_table* symtab_;
  Finish_group* finish_group_;
  Task_token* this_blocker_;
  Task_token* next_blocker_;
};

// This class is used to finish up handling a group.  It is just a
// closure.

class Finish_group : public Task
{
 public:
  Finish_group(Input_objects* input_objects, Symbol_table* symtab,
	       Layout* layout, Mapfile* mapfile, Input_group* input_group,
	       Task_token* next_blocker)
    : input_objects_(input_objects), symtab_(symtab),
      layout_(layout), mapfile_(mapfile), input_group_(input_group),
      saw_undefined_(0), this_blocker_(NULL), next_blocker_(next_blocker)
  { }

  ~Finish_group();

  // Set the number of undefined symbols when we start processing the
  // group.  This is called by the Start_group task.
  void
  set_saw_undefined(size_t saw_undefined)
  { this->saw_undefined_ = saw_undefined; }

  // Set the blocker to use for this task.
  void
  set_blocker(Task_token* this_blocker)
  {
    gold_assert(this->this_blocker_ == NULL);
    this->this_blocker_ = this_blocker;
  }

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const
  { return "Finish_group"; }

 private:
  Input_objects* input_objects_;
  Symbol_table* symtab_;
  Layout* layout_;
  Mapfile* mapfile_;
  Input_group* input_group_;
  size_t saw_undefined_;
  Task_token* this_blocker_;
  Task_token* next_blocker_;
};

// This class is used to read a file which was not recognized as an
// object or archive.  It tries to read it as a linker script, using
// the tokens to serialize with the calls to Add_symbols.

class Read_script : public Task
{
 public:
  Read_script(Symbol_table* symtab, Layout* layout, Dirsearch* dirpath,
	      int dirindex, Input_objects* input_objects, Mapfile* mapfile,
	      Input_group* input_group, const Input_argument* input_argument,
	      Input_file* input_file, Task_token* this_blocker,
	      Task_token* next_blocker)
    : symtab_(symtab), layout_(layout), dirpath_(dirpath), dirindex_(dirindex),
      input_objects_(input_objects), mapfile_(mapfile),
      input_group_(input_group), input_argument_(input_argument),
      input_file_(input_file), this_blocker_(this_blocker),
      next_blocker_(next_blocker)
  { }

  ~Read_script();

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const;

 private:
  Symbol_table* symtab_;
  Layout* layout_;
  Dirsearch* dirpath_;
  int dirindex_;
  Input_objects* input_objects_;
  Mapfile* mapfile_;
  Input_group* input_group_;
  const Input_argument* input_argument_;
  Input_file* input_file_;
  Task_token* this_blocker_;
  Task_token* next_blocker_;
};

} // end namespace gold

#endif // !defined(GOLD_READSYMS_H)