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/* elfutils::dwarf_ref_tracker -- DWARF reference tracking in -*- C++ -*-
Copyright (C) 2009 Red Hat, Inc.
This file is part of Red Hat elfutils.
Red Hat elfutils 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; version 2 of the License.
Red Hat elfutils 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 Red Hat elfutils; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
In addition, as a special exception, Red Hat, Inc. gives You the
additional right to link the code of Red Hat elfutils with code licensed
under any Open Source Initiative certified open source license
(http://www.opensource.org/licenses/index.php) which requires the
distribution of source code with any binary distribution and to
distribute linked combinations of the two. Non-GPL Code permitted under
this exception must only link to the code of Red Hat elfutils through
those well defined interfaces identified in the file named EXCEPTION
found in the source code files (the "Approved Interfaces"). The files
of Non-GPL Code may instantiate templates or use macros or inline
functions from the Approved Interfaces without causing the resulting
work to be covered by the GNU General Public License. Only Red Hat,
Inc. may make changes or additions to the list of Approved Interfaces.
Red Hat's grant of this exception is conditioned upon your not adding
any new exceptions. If you wish to add a new Approved Interface or
exception, please contact Red Hat. You must obey the GNU General Public
License in all respects for all of the Red Hat elfutils code and other
code used in conjunction with Red Hat elfutils except the Non-GPL Code
covered by this exception. If you modify this file, you may extend this
exception to your version of the file, but you are not obligated to do
so. If you do not wish to provide this exception without modification,
you must delete this exception statement from your version and license
this file solely under the GPL without exception.
Red Hat elfutils is an included package of the Open Invention Network.
An included package of the Open Invention Network is a package for which
Open Invention Network licensees cross-license their patents. No patent
license is granted, either expressly or impliedly, by designation as an
included package. Should you wish to participate in the Open Invention
Network licensing program, please visit www.openinventionnetwork.com
<http://www.openinventionnetwork.com>. */
#ifndef _ELFUTILS_DWARF_TRACKER
#define _ELFUTILS_DWARF_TRACKER 1
#include "dwarf"
#include "dwarf_comparator"
namespace elfutils
{
// Standard tracker.
template<class dwarf1, class dwarf2>
class dwarf_ref_tracker : public dwarf_tracker_base<dwarf1, dwarf2>
{
private:
typedef typename dwarf1::compile_units::const_iterator cu1;
typedef typename dwarf2::compile_units::const_iterator cu2;
typedef typename dwarf1::debug_info_entry::children::const_iterator die1;
typedef typename dwarf2::debug_info_entry::children::const_iterator die2;
/* We maintain the current path down the logical DIE tree from the CU
as a stack of iterators pointing to the DIE at each level. */
template<typename cu, typename die>
struct tracker
{
cu _m_root;
typedef std::list<die> die_path;
die_path _m_path;
/* We record every DIE we have seen here, mapping its .identity ()
to the die_path of parent DIEs taken to reach it. */
typedef std::tr1::unordered_map< ::Dwarf_Off, const die_path> die_map;
die_map _m_seen;
~tracker ()
{
// We should never be left with a partial walk on the books.
assert (_m_path.empty ());
}
inline const die_path &path_to (const die &a)
{
typename die_map::iterator it = _m_seen.find (a->identity ());
if (it == _m_seen.end ())
{
::Dwarf_Off id = a->identity ();
die_path path;
if (!walk_to (*_m_root, id, path))
throw std::runtime_error ("DIE not reachable from CU!");
it = _m_seen.insert (std::make_pair (id, path)).first;
}
return it->second;
}
// Return true if this is the droid we're looking for,
// or recurse on its children.
bool walk_to (const typename die::value_type from, ::Dwarf_Off to,
die_path &path)
{
if (from.identity () == to)
return true;
for (die it = from.children ().begin ();
it != from.children ().end ();
++it)
if (walk_to (it, to, path))
return true;
return false;
}
// Recursing on a child, include FROM in the path if the child matches.
bool walk_to (const die from, ::Dwarf_Off to, die_path &path)
{
if (walk_to (*from, to, path))
{
path.push_front (from);
return true;
}
return false;
}
inline void start_walk (const cu &a)
{
assert (_m_path.empty ());
_m_root = a;
}
inline void finish_walk (const cu &a)
{
assert (_m_path.empty ());
_m_root = cu ();
}
inline void pre_order (const die &a)
{
// Record the path down from the CU to see this DIE.
_m_seen.insert (std::make_pair (a->identity (), _m_path));
// Append this DIE to the path we'll record for its children.
_m_path.push_back (a);
}
inline void post_order (const die &a)
{
_m_path.pop_back ();
}
};
typedef tracker<cu1, die1> tracker1;
typedef tracker<cu2, die2> tracker2;
tracker1 _m_left;
tracker2 _m_right;
/* Predicate for DIEs "equal enough" to match as context for a subtree.
The definition we use is that the DIE has the same tag and all its
attributes are equal, excepting that references in attribute values
are not compared. */
struct equal_enough : public std::binary_function<die1, die2, bool>
{
inline bool operator () (const die1 &a, const die2 &b)
{
return (a->tag () == b->tag ()
&& (dwarf_comparator<dwarf1, dwarf2, true> ()
.equals (a->attributes (), b->attributes ())));
}
};
public:
inline void start_walk (const cu1 &a, const cu2 &b)
{
_m_left.start_walk (a);
_m_right.start_walk (b);
}
inline void finish_walk (const cu1 &a, const cu2 &b)
{
_m_left.finish_walk (a);
_m_right.finish_walk (b);
}
inline void pre_order (const die1 &a, const die2 &b)
{
_m_left.pre_order (a);
_m_right.pre_order (b);
}
inline void post_order (const die1 &a, const die2 &b)
{
_m_left.post_order (a);
_m_right.post_order (b);
}
typedef std::list<die1> left_context_type;
inline const left_context_type &left_context (const die1 &die)
{
return _m_left.path_to (die);
}
typedef std::list<die2> right_context_type;
inline const right_context_type &right_context (const die2 &die)
{
return _m_right.path_to (die);
}
// Very cheap check for an obvious mismatch of contexts.
inline bool context_quick_mismatch (const left_context_type &a,
const right_context_type &b)
{
return a.size () != a.size ();
}
// Full match when context_quick_mismatch has returned false.
inline bool context_match (const left_context_type &a,
const right_context_type &b)
{
return std::equal (a.begin (), a.end (), b.begin (), equal_enough ());
}
};
};
#endif // <elfutils/dwarf_tracker>
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