freebsd-dev/contrib/elftoolchain
Justin Hibbits d9a48fc632 Add missing powerpc64 relocation support to libdwarf
Summary:
Due to missing relocation support in libdwarf for powerpc64, handling of dwarf
info on unlinked objects was bogus.

Examining raw dwarf data on objects compiled on ppc64 with a modern compiler
(in-tree gcc tends to hide the issue, since it only rarely generates relocations
in .debug_info and uses DW_FORM_str instead of DW_FORM_strp for everything), you
will find that the dwarf data appears corrupt, with repeated references to the
compiler version where things like types and function names should appear.

This happens because the 0 offset of .debug_str contains the compiler version,
and without applying the relocations, *all* indirect strings in .dwarf_info will
end up pointing to it.

This corruption then propogates to the CTF data, as ctfconvert relies on
libdwarf to read the dwarf info, for every compiled object (when building a
kernel.)

However, if you examine the dwarf data on a compiled executable, it will appear
correct, because during final link the relocations get applied and baked in by
the linker.

Submitted by:	Brandon Bergren
Reviewed By:	emaste
Differential Revision: https://reviews.freebsd.org/D20367
2019-05-29 02:02:56 +00:00
..
addr2line Update to ELF Tool Chain r3668 2019-01-10 14:35:23 +00:00
ar Update to ELF Tool Chain r3668 2019-01-10 14:35:23 +00:00
brandelf Use the in-tree sys/elf_common.h to build libelftc. 2016-06-05 23:05:14 +00:00
common Update to ELF Tool Chain r3668 2019-01-10 14:35:23 +00:00
cxxfilt Update to ELF Tool Chain r3668 2019-01-10 14:35:23 +00:00
elfcopy Update to ELF Tool Chain r3668 2019-01-10 14:35:23 +00:00
elfdump Update ELF Tool Chain to r3614 2018-04-27 13:59:24 +00:00
libdwarf Add missing powerpc64 relocation support to libdwarf 2019-05-29 02:02:56 +00:00
libelf Drop "All rights reserved" from my copyright statements. 2019-03-06 22:11:45 +00:00
libelftc Update to ELF Tool Chain r3668 2019-01-10 14:35:23 +00:00
libpe Update ELF Tool Chain to r3614 2018-04-27 13:59:24 +00:00
nm Update to ELF Tool Chain r3668 2019-01-10 14:35:23 +00:00
readelf readelf: use size_t for object counts 2019-04-17 17:50:44 +00:00
size Update to ELF Tool Chain r3475 2016-05-20 17:24:34 +00:00
strings cap_fileargs: chase r346315, update fileargs_init in consumers 2019-04-17 16:18:14 +00:00
README.rst Update to ELF Tool Chain r3668 2019-01-10 14:35:23 +00:00

The Elftoolchain Project
========================

.. contents:: Table of Contents

Description
-----------

This software implements essential compilation tools and libraries for:

- managing program objects conforming to the ELF_ object format, and
- for managing DWARF_ debugging information in ELF objects.

The project currently implements the following utilities and
libraries:

=========== ============================================
Name        Description
=========== ============================================
ar          Archive manager.
addr2line   Debug tool.
brandelf    Manage the ELF brand on executables.
c++filt     Translate encoded symbols.
elfcopy     Copy and translate between object formats.
elfdump     Diagnostic tool.
findtextrel Find undesired text relocations.
libdwarf    DWARF access library.
libelf      ELF access library.
mcs         Manage comment sections.
nm          List symbols in an ELF object.
ranlib      Add archive symbol tables to an archive.
readelf     Display ELF information.
size        List object sizes.
strings     Extract printable strings.
strip       Discard information from ELF objects.
=========== ============================================

.. _ELF: http://en.wikipedia.org/wiki/Executable_and_Linkable_Format
.. _DWARF: http://www.dwarfstd.org/


Project Documentation
---------------------

- Release notes for released versions of this software are present in
  the file ``RELEASE-NOTES`` in the current directory.
- The file ``INSTALL`` in the current directory contains instructions
  on building and installing this software.
- Reference documentation in the form of manual pages is provided for
  the utilities and libraries developed by the project.
- Additional tutorial documentation is present in the
  ``documentation`` directory.


Tracking Ongoing Development
----------------------------

The project uses subversion_ for its version control system.

.. _subversion: https://subversion.apache.org/

The subversion branch for the current set of sources may be accessed
at the following URL::

    https://elftoolchain.svn.sourceforge.net/svnroot/elftoolchain/trunk

The project's source tree may be checked out from its repository by
using the ``svn checkout`` command::

    % svn checkout https://elftoolchain.svn.sourceforge.net/svnroot/elftoolchain/trunk

Checked-out sources may be kept upto-date by running ``svn update``
inside the source directory::

    % svn update


Instructions on building and installing the software are given in the
file ``INSTALL`` in the current directory.

Downloading Released Software
-----------------------------

Released versions of the project's software may also be downloaded
from SourceForge's `file release system`_.

.. _file release system: http://sourceforge.net/projects/elftoolchain/files/

Copyright and License
---------------------

This code is copyright its authors, and is distributed under the `BSD
License`_.

.. _BSD License: http://www.opensource.org/licenses/bsd-license.php


Developer Community
-------------------

The project's developers may be contacted using the mailing list:
``<elftoolchain-developers@lists.sourceforge.net>``.


Reporting Bugs
--------------

Please use our `Trac instance`_ for viewing existing bug reports and
for submitting new bug reports.

.. _`Trac instance`: http://sourceforge.net/apps/trac/elftoolchain/report


Additional Information
----------------------

Additional information about the project may be found on the `project
website`_.

.. _project website:  http://elftoolchain.sourceforge.net/

.. $Id: README.rst 3656 2018-12-26 09:46:24Z jkoshy $

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