libabigail/CONTRIBUTING
Dodji Seketeli 103a6eb94f Control symbols exported from libabigail.so
Symbols of pretty much all member functions of types that are meant to
be "private" to translation units that contribute to libabigail.so
were exported because we didn't do much to prevent that.

This patch starts controlling the set of symbols that are exported.

By default, symbols of any entity declared in a translation unit that
contributes to libabigail.so are hidden by default.  Only symbols of
entities declared in public headers (headers in include/*.h) are
exported.

There are many ways to achieve that.  This patch chooses to avoid
cluttering declarations of entities in the public header by adding
__attribute__((visibility="default")) to every declared type of
function in there.

Rather, the patch uses "#pragma GCC visibility push(default)" before
entities declared on those headers.  By doing so, all those entities
have their symbol marked as "visible" by the compiler.  Once the
header are #included, the #pragma GCC visibility pop" is used, so that
anything else has its symbol be hidden from that point on.

Note that for ease of maintenance the patch uses the macros
ABG_BEGIN_EXPORT_DECLARATIONS and ABG_END_EXPORT_DECLARATIONS rather
than using the pragma directive directly.

I believe this is a more elegant way of handling visibility, compared
to cluttering every single declaration in public headers with a
"__attribute__((visibility=("default")))" or with a macro which
expands to it.

This reduces the the set of symbols exported by libabigail.so from
20000+ to less than 5000.

	* VISIBILITY: New documentation about this visiblity business.
	* CONTRIBUTING: Update the "contributing guide" to refer to symbol
	visibility issues.
	* configure.ac: Define a variable VISIBILITY_FLAGS that is set to
	the -fvisibility=hidden flag to pass to GCC, when its available.
	* src/Makefile.am: Add VISIBILITY to source distribution.  Also
	add COMPILING and COMMIT-LOG-GUIDELINES that were missing.
	* src/Makefile.am: Use the new $(VISIBILITY_FLAGS) when buiding
	the library.
	* tests/Makefile.am: Use the new $(VISIBILITY_FLAGS) when buiding
	tests.
	* tools/Makefile.am: Use the new $(VISIBILITY_FLAGS) when buiding
	tools.
	* src/abg-comp-filter.cc: Enclose inclusion of public headers in
	ABG_BEGIN_EXPORT_DECLARATIONS and ABG_END_EXPORT_DECLARATIONS to
	export the symbols of entities declared in there.
	* src/abg-comparison.cc: Likewise.
	* src/abg-config.cc: Likewise.
	* src/abg-corpus.cc: Likewise.
	* src/abg-diff-utils.cc: Likewise.
	* src/abg-dwarf-reader.cc: Likewise.
	* src/abg-hash.cc: Likewise.
	* src/abg-ini.cc: Likewise.
	* src/abg-ir.cc: Likewise.
	* src/abg-libxml-utils.cc: Likewise.
	* src/abg-libzip-utils.cc: Likewise.
	* src/abg-reader.cc: Likewise.
	* src/abg-suppression.cc: Likewise.
	* src/abg-tools-utils.cc: Likewise.
	* src/abg-traverse.cc: Likewise.
	* src/abg-viz-common.cc: Likewise.
	* src/abg-viz-dot.cc: Likewise.
	* src/abg-viz-svg.cc: Likewise.
	* src/abg-workers.cc: Likewise.
	* src/abg-writer.cc: Likewise.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>
2016-07-27 12:51:02 +02:00

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Contact
=======
The project homepage is at https://sourceware.org/libabigail
The current libabigail source code can be checked out with:
git clone git://sourceware.org/git/libabigail
The mailing list to send messages and patches to is
libabigail@sourceware.org.
The archives of that list are available at http://sourceware.org/ml/libabigail.
File bugs
=========
Bugs are to be filled in bugzilla at
https://sourceware.org/bugzilla/enter_bug.cgi?product=libabigail
Writing and sending patches
============================
Please supply patches using git format-patch and git send-email. If
you don't know how to use git, send-email, fine. Just use your
favorite email client, attach the patch to a nice message, and send us
the message.
Patches have to be sent by email to libabigail@sourceware.org.
Please read the file COMMIT-LOG-GUIDELINES in the source tree to learn
about how to write the commit log accompanying the patch.
If you are adding a new public header file to the project, or if you
are defining a new entry point to the API of libabigail, please take
some time to read the file VISIBILITY about how you need to handle the
visibility of symbols that are part of the API and ABI of libabigail.
Make sure you sign your patch. To learn about signing, please read
the "Sign your work" chapter below.
One important thing to be before sending your patch is to launch the
regression tests.
Regression tests
================
Regression tests are under the directory 'tests'. They are usually
written in C++ and are especially designed to be easy to debug. The
idea is that if the test fails, the programmer should just have to
launch them under GDB and debug them right away. No-bullshit style.
Regression tests are launched by doing:
make check
If you have N processor cores on your machine, you can launch the
tests in parallel to make whole thing go faster by doing:
make -jN -lN check
If you want to test the fabrication of the distribution tarball (this
is important, because that is how we do to actually release the
tarball of the project that you can download from the internet) then
you can do:
make distcheck
This actually builds the tarball, then untars it, configure/compile
the untarred source code and launches the regression checks from
there.
You can also launch this in parallel by doing:
make -jN -lN distcheck
with N being the number of processor core you have on your system.
Please make sure you always launch "make distcheck" before sending a
patch, so that you are sure that we can always build a tarball after
your patch is applied to the source tree.
Launching regression tests in Valgrind
--------------------------------------
To detect memory management errors, the tests of the regression test
suite can be run using Valgrind tools, essentially memcheck and
helgrind.
To do so, please do:
make check-valgrind
This runs the tests under the control of Valgrind memcheck and
helgrind tools.
But then, if you want Valgrind to check the libabigail command line
tools that are *forked* by some of the tests then type:
make check-valgrind-recursive
This one takes a long time. On my system for instance, it takes an
hour. But then it checks *everything*. If you don't have that time,
then "make check-valgrind" is enough, as the regression tests that use
the libabigail *library* directly (as opposed to forking libabigail
command line tools) will be verified.
How tests are organized
-----------------------
There are two kinds of regression tests. Those that use the
libabigail *library* directly, and those that spawn one of the
libabigail command line tools.
Generally, both are usually made of a loop that churns through a set of input
binaries to compare. Once the comparison is done, the resulting
report is compared against a reference report that is provided.
Test executable have names that starts with 'runtest*'. For instance,
under <build-directory>/tests/ you can find tests named
runtestdiffdwarf, runtestabidiff, etc...
If a test executable is named
<build-directory>/tests/runtestdiffdwarf, then its source code is
tests/test-diff-dwarf.cc. Similarly, the source code of the test
<build-directory>/tests/runtestabidiff is tests/test-abidiff.cc.
The data provided for each test (for instance the input binaries to
compare and the reference report that should result from the
comparison) is to be found under tests/data. So data for the test
runtestdiffdwarf is to be found under tests/data/test-diff-dwarf.
Data for the test runtestabidiff is to be found under
tests/data/test-abidiff.cc.
So adding your own tests usually just amounts to adding the input
right input into the right sub-directory of tests/data/. To do so,
look at several tests/test-*.cc to see which one you'd like to add
some input binaries to be compared in.
Then once you know which tests/test-*.cc you'd like to extend, and if
you added your input binaries and reference reports (maybe other
things too) to the right sub-director of tests/data/, you just need to
extend the array of input binaries/reference reports that the test
walks to perform the comparisons. It's generally a global variable
before the main() function of the test. In test-diff-dwarf.cc, for
instance, the variable name is "in_out_specs". You just have to add a
new entry to that array; that new entry contains the paths to your new
input binaries and reference reports. Just read the code in there and
use your brains. It should be straight forward.
Ah, also, if you added new files for the tests, then the build system
needs to be told that those files have to be added to the distribution
tarball when we do "make dist" (or make distcheck). To do so, please
make sure to add your new test input files to the
tests/data/Makefile.am file, in the EXTRA_DIST variable. Look at how
things are organized in that file, and please do things similarly.
Sign your work
==============
To facilitate tracking of who did what, we've adopted a "sign-off"
procedure for patches based on the procedure used by the Linux kernel
project.
The sign-off is a simple line at the end of the explanation for the
patch, which certifies that you wrote it or otherwise have the right
to pass it on as a patch under an appropriate license. The rules are
pretty simple: if you can certify the below:
Developer's Certificate of Origin
By making a contribution to this project, I certify that:
(a) The contribution was created in whole or in part by me,
and I have the right to submit the contribution under the
license indicated in, or otherwise designated as being
applicable to, the file.
(b) The contribution was provided directly to me by some other
person who certified (a), and I have not modified it.
(c) I understand and agree that the project and the
contribution are public and that a record of the
contribution (including all personal information I submit
with it, including my sign-off) is maintained indefinitely
and may be redistributed.
then you just add a line saying
Signed-off-by: Random J Developer <random@developer.example.org>
using your real name (sorry, no pseudonyms or anonymous contributions.)
git commit --signoff will add such a Signed-off-by line at the end of
the commit log message for you.
Modifying the website
=====================
The source code of the website of libabigail is stored in CVS (sigh,
yeah, that is so old school). You can check out that web source code
by doing:
CVS_RSH=ssh cvs -z9 -d :ext:user@sourceware.org:/cvs/libabigail/ co htdocs
where 'user' is your username on the sourceware system.
Alternatively, you can check out the the web source code anonymously,
if you don't have any user account on the sourceware system by doing:
export CVSROOT=:pserver:anoncvs@cygwin.com:/cvs/libabigail
cvs login
(the CVS anonymous password to use is "anoncvs")
cvs checkout htdocs
Happy Hacking!