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CTF (C Type Format) is a lightweight debugging format that provides information about C types and the association between functions and data symbols and types. It is designed to be very compact and simple. More can be learned about it at https://ctfstd.org. This patch introduces support in libabigail to extract ABI information from CTF stored in ELF files. A few notes on this implementation: - The implementation is complete in terms of CTF support. Every CTF feature is processed and handled to generate libabigail IR. This includes basic types, typedefs, pointer, array and struct types. The CTF record of data objects (variables) and functions are also used in order to generate the corresponding libabigail IR artifacts. - The decoding of CTF data is done using the libctf library which is part of binutils. In order to link with it, binutils shall be built with --enable-shared for libctf.so to become available. - This initial implementation is aimed to simplicity. We have not tried to resolve any and every corner case that may require special handling. We have observed that the DWARF front-end (which is naturally way more complex as the scope is way bigger) is plagued with hacks to handle such situations. However, for the CTF support we prefer to proceed in a simpler and more modest way: we will handle these problems if/when we find them. The fact that CTF only supports C (currently) certainly helps there. - Likewise, in this basic support we are not handling symbol suppressions or other goodies that libabigail provides. We are new to libabigail and ABI analysis, and at this point we simply don't have a clear picture about what is most useful/relevant to support or not. With the maintainer's blesssing, we will tackle that functionaly after this basic support is applied upstream. - The implementation in abg-ctf-reader.{cc,h} is pretty much self-contained. As a result there is some duplication in terms of ELF handling with the DWARF reader, but since that logic is very simple and can be easily implemented, we don't consider this to be a big deal (for now.) Hopefully the maintainers agree. - The libabigail tools assume that ELF means to always use DWARF to generate the ABI IR. We added a new command-line option --ctf to the tools in order to make them to use the CTF debug info instead. We are definitely not sure whether this is the best user interface. In fact I would be suprised if it was ;) - We added support for --ctf to both abilint and abidiff. We are not sure whether it would make sense to add support for CTF to the other tools. Feedback welcome. - We are pondering about what to do in terms of testing. We have cursory tested this implementation using abilint and abidiff. We know we are generating IR corpus that seem to be ok. It would be good however to be able to run the libabigail testsuites using CTF. However the testsuites may need some non-trivial changes in order to make this possible. Let's talk about that :) * configure.ac: Check for libctf. * src/abg-ctf-reader.cc: New file. * include/abg-ctf-reader.h: Likewise. * src/Makefile.am (libabigail_la_SOURCES): Add abg-ctf-reader.cc conditionally. * include/Makefile.am (pkginclude_HEADERS): Add abg-ctf-reader.h conditionally. * tools/abilint.cc (struct options): New option `use_ctf'. (display_usage): Documentation for --ctf. (parse_command_line): Handle --ctf. (main): Honour --ctf. * tools/abidiff.cc (struct options): New option `use_ctf'. (display_usage): Documentation for --ctf. (parse_command_line): Handle --ctf. (main): Honour --ctf. * doc/manuals/abidiff.rst: Document --ctf. * doc/manuals/abilint.rst: Likewise. Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com> Signed-off-by: Dodji Seketeli <dodji@redhat.com> |
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.gitignore | ||
abicompat.cc | ||
abidiff.cc | ||
abidw.cc | ||
abilint.cc | ||
abipkgdiff.cc | ||
abisym.cc | ||
binilint.cc | ||
fedabipkgdiff | ||
kmidiff.cc | ||
Makefile.am |