gold/cref.cc

// cref.cc -- cross reference for gold

// Copyright (C) 2008-2021 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.

#include "gold.h"

#include <cerrno>
#include <cstdio>
#include <cstring>
#include <map>
#include <string>
#include <vector>

#include "object.h"
#include "archive.h"
#include "symtab.h"
#include "cref.h"

namespace gold
{

// Class Cref_inputs.  This is used to hold the list of input files
// for cross referencing.

class Cref_inputs
{
 public:
  Cref_inputs()
    : objects_(), archives_(), current_(&this->objects_)
  { }

  // Add an input object file.
  void
  add_object(Object* object);

  // Start adding an archive.  We support nested archives for future
  // flexibility.
  void
  add_archive_start(Archive*);

  // Finish adding an archive.
  void
  add_archive_stop(Archive*);

  // Report symbol counts.
  void
  print_symbol_counts(const Symbol_table*, FILE*) const;

  // Print a cross reference table.
  void
  print_cref(const Symbol_table*, FILE*) const;

 private:
  // A list of input objects.
  typedef std::vector<Object*> Objects;

  // Information we record for an archive.
  struct Archive_info
  {
    // Archive name.
    std::string name;
    // List of objects included from the archive.
    Objects* objects;
    // Number of archive members.
    size_t member_count;
  };

  // A mapping from the name of an archive to the list of objects in
  // that archive.
  typedef std::map<std::string, Archive_info> Archives;

  // For --cref, we build a cross reference table which maps from
  // symbols to lists of objects.  The symbols are sorted
  // alphabetically.

  class Cref_table_compare
  {
  public:
    bool
    operator()(const Symbol*, const Symbol*) const;
  };

  typedef std::map<const Symbol*, Objects*, Cref_table_compare> Cref_table;

  // Report symbol counts for a list of Objects.
  void
  print_objects_symbol_counts(const Symbol_table*, FILE*, const Objects*) const;

  // Report symbol counts for an object.
  void
  print_object_symbol_counts(const Symbol_table*, FILE*, const Object*) const;

  // Gather cross reference information.
  void
  gather_cref(const Objects*, Cref_table*) const;

  // List of input objects.
  Objects objects_;
  // List of input archives.  This is a mapping from the archive file
  // name to the list of objects.
  Archives archives_;
  // The list to which we are currently adding objects.
  Objects* current_;
};

// Add an object.

void
Cref_inputs::add_object(Object* object)
{
  this->current_->push_back(object);
}

// Start adding an archive.

void
Cref_inputs::add_archive_start(Archive* archive)
{
  gold_assert(this->current_ == &this->objects_);
  if (this->archives_.find(archive->name()) == this->archives_.end())
    {
      Archive_info* pai = &this->archives_[archive->name()];
      pai->name = archive->filename();
      pai->objects = new Objects();
      pai->member_count = archive->count_members();
    }
  this->current_ = this->archives_[archive->name()].objects;
}

// Stop adding an archive.

void
Cref_inputs::add_archive_stop(Archive*)
{
  gold_assert(this->current_ != &this->objects_);
  this->current_ = &this->objects_;
}

// Report symbol counts for an object.

void
Cref_inputs::print_object_symbol_counts(const Symbol_table* symtab,
					FILE* f,
					const Object* object) const
{
  size_t defined, used;
  object->get_global_symbol_counts(symtab, &defined, &used);
  fprintf(f, "symbols %s %zu %zu\n", object->name().c_str(), defined, used);
}

// Report symbol counts for a list of inputs.

void
Cref_inputs::print_objects_symbol_counts(const Symbol_table* symtab,
					 FILE* f,
					 const Objects* objects) const
{
  for (Objects::const_iterator p = objects->begin();
       p != objects->end();
       ++p)
    this->print_object_symbol_counts(symtab, f, *p);
}

// Print symbol counts.  This implements --print-symbol-counts.  This
// is intended to be easily read by a program.  This outputs a series
// of lines.  There are two different types of lines.

// The first is "symbols FILENAME DEFINED USED".  FILENAME is the name
// of an object file included in the link; for an archive, this will
// be ARCHIVEFILENAME(MEMBERNAME).  DEFINED is the number of symbols
// which the object file defines.  USED is the number of symbols which
// are used in the final output; this is the number of symbols which
// appear in the final output table as having been defined by this
// object.  These numbers will be different when weak symbols are
// used, and they will be different for dynamic objects.

// The second is "archives FILENAME MEMBERS USED".  FILENAME is the
// name of an archive file included in the link.  MEMBERS is the
// number of members of the archive.  USED is the number of archive
// members included in the link.

void
Cref_inputs::print_symbol_counts(const Symbol_table* symtab, FILE* f) const
{
  this->print_objects_symbol_counts(symtab, f, &this->objects_);
  for (Archives::const_iterator p = this->archives_.begin();
       p != this->archives_.end();
       ++p)
    {
      fprintf(f, "archive %s %zu %zu\n", p->second.name.c_str(),
	     p->second.member_count, p->second.objects->size());
      this->print_objects_symbol_counts(symtab, f, p->second.objects);
    }
}

// Sort symbols for the cross reference table.

bool
Cref_inputs::Cref_table_compare::operator()(const Symbol* s1,
					    const Symbol* s2) const
{
  int i = strcmp(s1->name(), s2->name());
  if (i != 0)
    return i < 0;

  if (s1->version() == NULL)
    {
      if (s2->version() != NULL)
	return true;
    }
  else if (s2->version() == NULL)
    return false;
  else
    {
      i = strcmp(s1->version(), s2->version());
      if (i != 0)
	return i < 0;
    }

  // We should never have two different symbols with the same name and
  // version, where one doesn't forward to the other.
  if (s1 == s2)
    return false;
  if (s1->is_forwarder() && !s2->is_forwarder())
    return true;
  if (!s1->is_forwarder() && s2->is_forwarder())
    return false;
  gold_unreachable();
}

// Gather cross reference information from a list of inputs.

void
Cref_inputs::gather_cref(const Objects* objects, Cref_table* table) const
{
  for (Objects::const_iterator po = objects->begin();
       po != objects->end();
       ++po)
    {
      const Object::Symbols* symbols = (*po)->get_global_symbols();
      if (symbols == NULL)
	continue;
      for (Object::Symbols::const_iterator ps = symbols->begin();
	   ps != symbols->end();
	   ++ps)
	{
	  const Symbol* sym = *ps;
	  if (sym == NULL)
	    continue;
	  Objects* const onull = NULL;
	  std::pair<Cref_table::iterator, bool> ins =
	    table->insert(std::make_pair(sym, onull));
	  Cref_table::iterator pc = ins.first;
	  if (ins.second)
	    pc->second = new Objects();
	  if (sym->source() == Symbol::FROM_OBJECT
	      && sym->object() == *po
	      && sym->is_defined())
	    pc->second->insert(pc->second->begin(), *po);
	  else
	    pc->second->push_back(*po);
	}
    }
}

// The column where the file name starts in a cross reference table.

static const size_t filecol = 50;

// Print a cross reference table.

void
Cref_inputs::print_cref(const Symbol_table*, FILE* f) const
{
  Cref_table table;
  this->gather_cref(&this->objects_, &table);
  for (Archives::const_iterator p = this->archives_.begin();
       p != this->archives_.end();
       ++p)
    this->gather_cref(p->second.objects, &table);

  for (Cref_table::const_iterator pc = table.begin();
       pc != table.end();
       ++pc)
    {
      // If all the objects are dynamic, skip this symbol.
      const Symbol* sym = pc->first;
      const Objects* objects = pc->second;
      Objects::const_iterator po;
      for (po = objects->begin(); po != objects->end(); ++po)
	if (!(*po)->is_dynamic())
	  break;
      if (po == objects->end())
	continue;

      std::string s = sym->demangled_name();
      if (sym->version() != NULL)
	{
	  s += '@';
	  if (sym->is_default())
	    s += '@';
	  s += sym->version();
	}

      fputs(s.c_str(), f);

      size_t len = s.length();

      for (po = objects->begin(); po != objects->end(); ++po)
	{
	  int n = len < filecol ? filecol - len : 1;
	  fprintf(f, "%*c%s\n", n, ' ', (*po)->name().c_str());
	  len = 0;
	}
    }
}

// Class Cref.

// Make sure the Cref_inputs object has been created.

void
Cref::need_inputs()
{
  if (this->inputs_ == NULL)
    this->inputs_ = new Cref_inputs();
}

// Add an input object file.

void
Cref::add_object(Object* object)
{
  this->need_inputs();
  this->inputs_->add_object(object);
}

// Start adding an archive.

void
Cref::add_archive_start(Archive* archive)
{
  this->need_inputs();
  this->inputs_->add_archive_start(archive);
}

// Stop adding an archive.

void
Cref::add_archive_stop(Archive* archive)
{
  this->inputs_->add_archive_stop(archive);
}

// Print symbol counts.

void
Cref::print_symbol_counts(const Symbol_table* symtab) const
{
  if (parameters->options().user_set_print_symbol_counts()
      && this->inputs_ != NULL)
    {
      FILE* f;
      if (strcmp(parameters->options().print_symbol_counts(), "-") == 0)
	f = stdout;
      else
	{
	  f = fopen(parameters->options().print_symbol_counts(), "w");
	  if (f == NULL)
	    gold_error(_("cannot open symbol count file %s: %s"),
		       parameters->options().print_symbol_counts(),
		       strerror(errno));
	}
      if (f != NULL)
	this->inputs_->print_symbol_counts(symtab, f);
    }
}

// Print a cross reference table.

void
Cref::print_cref(const Symbol_table* symtab, FILE* f) const
{
  fprintf(f, _("\nCross Reference Table\n\n"));
  const char* msg = _("Symbol");
  int len = filecol - strlen(msg);
  fprintf(f, "%s%*c%s\n", msg, len, ' ', _("File"));

  if (parameters->options().cref() && this->inputs_ != NULL)
    this->inputs_->print_cref(symtab, f);
}

} // End namespace gold.