Bug 28669 Increment Library version

  Add library version to libabigail 2.1 to not cause problems with older
utilities due to library version incompatibility. This will also stop
tools that look for libraries which have a different ABI but the same
version from complaining.

	* src/Makefile.am: Add library version.

Signed-off-by: Ben Woodard <woodard@redhat.com>
---
 src/Makefile.am | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
  

Hello,

Ben Woodard via Libabigail <libabigail@sourceware.org> a écrit:

> Add library version to libabigail 2.1 to not cause problems with older
> utilities due to library version incompatibility. This will also stop
> tools that look for libraries which have a different ABI but the same
> version from complaining.
>
> 	* src/Makefile.am: Add library version.

This is nice and long overdue, so Thank You for getting your hands dirty on
this task.

I have slightly augmented the change to define the CURRENT,REVISION and
AGE libtool variables in the configure.ac file so that we can update
them there at release time, just like what we do for the major and minor
version numbers of the project as well as the ABIXML version numbers.
The -version option passed to the linker then re-uses the libtool
variables defined in configure.ac.

Below is the resulting patch that I am applying to master to that
effect.

Cheers,
 
From 2bfea52331211cf16fba00d4d2a40f9bbc679cf8 Mon Sep 17 00:00:00 2001
From: Ben Woodard via Libabigail <libabigail@sourceware.org>
Date: Tue, 28 Jun 2022 15:26:00 -0700
Subject: [PATCH] Bug 28669 - Increment Library version

Add libtool versioning to libabigail.so starting from 2.1 onward to
not cause problems with older utilities due to library version
incompatibility. This will also stop tools that look for libraries
which have a different ABI but the same version from complaining.

	* configure.ac: Define the variables libabigail_so_{current,
	revision, age}.  These are to be adjusted after each releases
	depending on how the compatibility status of the libabigail's
	code.
	* src/Makefile.am: Add -version-info
	$(LIBABIGAIL_SO_CURRENT):$(LIBABIGAIL_SO_REVISION):$(LIBABIGAIL_SO_AGE)
	to LDFLAGS.

Signed-off-by: Ben Woodard <woodard@redhat.com>
Signed-off-by: Dodji Seketeli <dodji@redhat.com>
---
 configure.ac    | 33 +++++++++++++++++++++++++++++++++
 src/Makefile.am |  2 +-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 97b3469f..ee8885e9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,7 +1,34 @@
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+dnl Libabigail version number is handled here with the major and minor
+dnl version numbers.
 m4_define([version_major],   [2])
 m4_define([version_minor],   [1])
 
+dnl Below are the numbers to handle libabigail.so's versionning
+dnl following the libtool's versionning scheme to handle shared
+dnl libraries' compatibility.
+dnl
+dnl Below are the rules to follow to update the three numbers
+dnl (LIBABIGAIL_SO_CURRENT, LIBABIGAIL_SO_REVISION and LIBABIGAIL_SO_AGE):
+dnl
+dnl 1. If the library source code has changed at all since the last
+dnl    update, then increment LIBABIGAIL_SO_REVISION ('C:R:A' becomes
+dnl    'C:R+1:A').
+dnl 
+dnl 2. If any interfaces have been added, removed, or changed since
+dnl    the last update, increment LIBABIGAIL_SO_CURRENT, and set
+dnl    LIBABIGAIL_REVISION to 0.
+dnl 
+dnl 3. If any interfaces have been added since the last public release,
+dnl    then increment LIBABIGAIL_SO_AGE.
+dnl 
+dnl 4. If any interfaces have been removed or changed since the last
+dnl     public release, then set LIBABIGAIL_SO_AGE to 0.
+m4_define([libabigail_so_current],  [1])
+m4_define([libabigail_so_revision], [0])
+m4_define([libabigail_so_age],      [0])
+
 AC_INIT([libabigail],
 	[version_major.version_minor],
 	[http://sourceware.org/bugzilla],
@@ -40,12 +67,18 @@ VERSION_MINOR=version_minor
 VERSION_REVISION=0
 ABIXML_VERSION_MAJOR=2
 ABIXML_VERSION_MINOR=1
+LIBABIGAIL_SO_CURRENT=libabigail_so_current
+LIBABIGAIL_SO_REVISION=libabigail_so_revision
+LIBABIGAIL_SO_AGE=libabigail_so_age
 
 AC_SUBST(VERSION_MAJOR)
 AC_SUBST(VERSION_MINOR)
 AC_SUBST(VERSION_REVISION)
 AC_SUBST(ABIXML_VERSION_MAJOR)
 AC_SUBST(ABIXML_VERSION_MINOR)
+AC_SUBST(LIBABIGAIL_SO_CURRENT)
+AC_SUBST(LIBABIGAIL_SO_REVISION)
+AC_SUBST(LIBABIGAIL_SO_AGE)
 
 dnl This VERSION_SUFFIX environment variable is to allow appending
 dnl arbitrary text to the libabigail version string representation.
diff --git a/src/Makefile.am b/src/Makefile.am
index 1591224f..1748f0b8 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -47,7 +47,7 @@ libabigail_la_SOURCES += abg-ctf-reader.cc
 endif
 
 libabigail_la_LIBADD = $(DEPS_LIBS) $(FTS_LIBS)
-libabigail_la_LDFLAGS = -lpthread -Wl,--as-needed -no-undefined
+libabigail_la_LDFLAGS = -lpthread -Wl,--as-needed -no-undefined -version-info $(LIBABIGAIL_SO_CURRENT):$(LIBABIGAIL_SO_REVISION):$(LIBABIGAIL_SO_AGE)
 
 CUSTOM_MACROS = -DABIGAIL_ROOT_SYSTEM_LIBDIR=\"${libdir}\"