Use cross compiler for doc examples

Signed-off-by: Cristiana Voicu <cristiana.voicu@intel.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fix: tls-compat multi-lib conflict

When configured with the TLS pthread key fallback either:

- explicitly with ./configure --disable-compiler-tls,
- or if compiler TLS is not usable,

(this can be confirmed by looking at the configure output:
Thread Local Storage (TLS): pthread_getspecific().)

There is an issue when using multiple flavors of RCU within the same
program. Unit tests concerned:

tests/unit/test_urcu_multiflavor
tests/unit/test_urcu_multiflavor_dynlink

Vladimir Nikulichev noticed crashes when using this setup. The problem
can be pinpointed to a missing macro expansion in urcu/tls-compat.h:

looking at the output of

nm tests/unit/.libs/test_urcu_multiflavor :

                 U __tls_access_rcu_reader

this seems to be the issue. We're missing macro expansion in
tls-compat.h. With this commit, it becomes:

                 U __tls_access_rcu_reader_bp
                 U __tls_access_rcu_reader_mb
                 U __tls_access_rcu_reader_memb
                 U __tls_access_rcu_reader_sig

Please note that this affects an unusual configuration of userspace RCU
(with TLS pthread key fallback), needed for some BSD that don't support
compiler TLS. Strictly speaking, this requires bumping the URCU library
soname version major number, because it breaks the ABI presented to
applications on those unusual configurations.

A following commit will handle the ABI migration: for stable releases
(stable-0.7 and stable-0.8 branches), the ABI is kept compatible, and
bogus usage are detected. For the upcoming stable-0.9, the soname will
simply be bumped.

Reported-by: Vladimir Nikulichev <nvs@tbricks.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Library major version number (soname) increment to 3

Due to the urcu/tls-compat.h TLS fallback symbol clash fix, we need to
bump the Userspace RCU soname major version number so we don't have to
keep erroneous usage detection code around.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
rculfhash: document max_nr_buckets = 0

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Blacklist ARM gcc 4.8.0, 4.8.1, 4.8.2

It produces clobbered frame accesses, which can lead to stack corruption
when racing with signal handlers nested on stack.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Android: configure.ac Android check

Set TARGET_IS_ANDROID to true if target is Android.

Signed-off-by: Charles Briere <charlesbriere.flatzo@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Android: do not link pthread on Android

On Android, pthread is already part of libc called Bionic and doesn't
have an external library to link with.

Signed-off-by: Charles Briere <charlesbriere.flatzo@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Android: add a compat layer for 'syscall.h'

Path to include syscall.h is different on Android.

Signed-off-by: Charles Briere <charlesbriere.flatzo@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Android: do not redefine gettid on Android

Bionic already defines gettid through <unistd.h>.

Signed-off-by: Charles Briere <charlesbriere.flatzo@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Android: implement rand_r()

stdlib.h doesn't implement rand_r() on Android.

Signed-off-by: Charles Briere <charlesbriere.flatzo@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fix undefined NULL pointer arithmetic

Clang 3.3 with -O2 optimisations is especially picky about arithmetic
on NULL pointers. This undefined behavior is turned into optimized out
NULL checks by clang 3.3. Fix the undefined behavior by checking against
the pointer directly, without going back and forth around NULL with
pointer arithmetic.

Reported-by: Zifei Tong <soariez@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cleanup: Android: Do not redefine gettid

When compiling with Android Toolchain, gettid is already defined in
<unistd.h> and therefore doesn't need to be reimplemented. This patch
checks for gettid instead of looking for Android in case other
environements behave the same way.

Signed-off-by: Charles Briere <charlesbriere.flatzo@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cleanup: Check for pthread in Libc

Some libc like Googles's Bionic for Android include pThread. Instead of
checking for Android as in commit
58a052effb2305655ff1b7233c78ab24fc25257e this patch checks for pthread
in libc as proposed by Thomas Petazzoni.

Reported-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Charles Briere <charlesbriere.flatzo@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fix undefined NULL pointer arithmetic in hlist

Clang 3.3 with -O2 optimisations is especially picky about arithmetic on
NULL pointers. This undefined behavior is turned into optimized out NULL
checks by clang 3.3. Fix the undefined behavior by checking against the
pointer directly, without going back and forth around NULL with
pointer arithmetic.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Set RCU_HAVE_FENCE to false on Intel Xeon Phi

It currently fails to compile, because the Phi does not have fence
instructions.

It will use lock prefixed instructions for all memory barriers, which
is overkill for this platform, but at least it will work.

Signed-off-by: Simon Marchi <simon.marchi@polymtl.ca>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
x86 barrier for Xeon Phi: use rsp on x86-64

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fix: urcu-bp interaction with threads vs constructors/destructors

Add a reference counter for threads using urcu-bp, thus ensuring that
even if the urcu destructor is executed before each thread using RCU
read-side critical sections exit, those threads will not see a corrupted
thread list.

Also, don't use URCU_TLS() within urcu_bp_thread_exit_notifier(). It
appears that this is racy (although this was probably due to the issue
fixed by reference counting). Anyway, play safe, and pass the rcu_key
received as parameter instead.

Those issues only reproduce when threads are still active when the
urcu-bp destructor is called.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>