[0/1] Make front-ends be first class in the libabigail framework

  Hello,

I have been exploring the idea of making front-ends in libabigail be
first class citizens.

The goal of this change is  twofold:

First, it's to improve the integration and maintenance of the new CTF
front-end in the libabigail framework.  Today, the code of the CTF
front-end is guarded by #ifdef WITH_CTF pre-processor macro
invocations.  Ideally, the amount code guarded by that macro should be
minimal (and ideally be zero in the future), especially in the
libabigail tools (abidw, abidiff, abipkgdiff, etc) that use the
library.

Second, it's to allow and ease the inclusion new front-ends in the
future, for instance, to support other ELF-based debug info formats.

The idea is to provide new abstractions in the libabigail framework to
represent a front-end and to share code between similar front-ends.
For instance, front-ends that are ELF-based (DWARF/CTF) would share
the code to access generic ELF properties.

Tools would thus be better equipped to analyze a binary and depending
on its kind, instantiate the appropriate front-end for its ABI
analysis and use it accordingly.

This thread contains the change proposal to implement this "feature".

Note that the change is implemented in a single patch as all the
changes are quite intermingled, to be honest.

In any case, the change can be access from the Git repository in the
"front-end" branch, which can be browsed from
https://sourceware.org/git/?p=libabigail.git;a=shortlog;h=refs/heads/users/dodji/front-end

Please, find the summary log of the change below.

Dodji Seketeli (1):
  Make Front Ends first class citizens

 include/Makefile.am                        |    4 +-
 include/abg-corpus.h                       |   18 +-
 include/abg-ctf-reader.h                   |   33 +-
 include/abg-dwarf-reader.h                 |  124 +-
 include/abg-elf-based-reader.h             |   63 +
 include/abg-elf-reader-common.h            |   70 -
 include/abg-elf-reader.h                   |  155 +
 include/abg-fe-iface.h                     |  166 +
 include/abg-fwd.h                          |    2 +-
 include/abg-ir.h                           |  156 +-
 include/abg-reader.h                       |   62 +-
 include/abg-suppression.h                  |   67 +
 include/abg-tools-utils.h                  |   13 +-
 include/abg-writer.h                       |    2 +-
 src/Makefile.am                            |    4 +-
 src/abg-comparison.cc                      |   67 +-
 src/abg-corpus-priv.h                      |   18 +-
 src/abg-corpus.cc                          |   73 +-
 src/abg-ctf-reader.cc                      | 1545 ++++----
 src/abg-dwarf-reader.cc                    | 3849 +++++++-------------
 src/abg-elf-based-reader.cc                |  102 +
 src/abg-elf-helpers.cc                     |  183 +-
 src/abg-elf-helpers.h                      |   38 +
 src/abg-elf-reader-common.cc               |   90 -
 src/abg-elf-reader.cc                      |  890 +++++
 src/abg-fe-iface.cc                        |  411 +++
 src/abg-ir-priv.h                          |   57 +-
 src/abg-ir.cc                              |  817 ++---
 src/abg-reader.cc                          | 1974 +++++-----
 src/abg-suppression-priv.h                 |  179 -
 src/abg-suppression.cc                     |  479 ++-
 src/abg-symtab-reader.cc                   |    5 +-
 src/abg-symtab-reader.h                    |    6 +-
 src/abg-tools-utils.cc                     |  163 +-
 src/abg-writer.cc                          |   39 +-
 tests/data/test-read-ctf/test0.abi         |    3 +
 tests/data/test-read-ctf/test0.hash.abi    |    3 +
 tests/data/test-read-ctf/test1.so.abi      |    3 +
 tests/data/test-read-ctf/test1.so.hash.abi |    3 +
 tests/data/test-read-ctf/test2.so.abi      |    3 +
 tests/data/test-read-ctf/test2.so.hash.abi |    3 +
 tests/data/test-read-ctf/test3.so.abi      |    5 +-
 tests/data/test-read-ctf/test3.so.hash.abi |    5 +-
 tests/data/test-read-ctf/test4.so.abi      |    3 +
 tests/data/test-read-ctf/test4.so.hash.abi |    3 +
 tests/print-diff-tree.cc                   |   12 +-
 tests/test-abidiff.cc                      |   24 +-
 tests/test-diff-dwarf.cc                   |   20 +-
 tests/test-ir-walker.cc                    |    7 +-
 tests/test-read-ctf.cc                     |   20 +-
 tests/test-read-dwarf.cc                   |    3 -
 tests/test-read-write.cc                   |    3 -
 tests/test-symtab.cc                       |   42 +-
 tools/Makefile.am                          |   13 +-
 tools/abicompat.cc                         |   63 +-
 tools/abidiff.cc                           |  222 +-
 tools/abidw.cc                             |  178 +-
 tools/abilint.cc                           |  128 +-
 tools/abipkgdiff.cc                        |  222 +-
 tools/abisym.cc                            |    5 +-
 tools/kmidiff.cc                           |   14 +-
 61 files changed, 6365 insertions(+), 6569 deletions(-)
 create mode 100644 include/abg-elf-based-reader.h
 delete mode 100644 include/abg-elf-reader-common.h
 create mode 100644 include/abg-elf-reader.h
 create mode 100644 include/abg-fe-iface.h
 create mode 100644 src/abg-elf-based-reader.cc
 delete mode 100644 src/abg-elf-reader-common.cc
 create mode 100644 src/abg-elf-reader.cc
 create mode 100644 src/abg-fe-iface.cc