Add pretty printers for the NPTL lock types

This patch adds pretty printers for the following NPTL types:

- pthread_mutex_t
- pthread_mutexattr_t
- pthread_cond_t
- pthread_condattr_t
- pthread_rwlock_t
- pthread_rwlockattr_t

To load the pretty printers into your gdb session, do the following:

python
import sys
sys.path.insert(0, '/path/to/glibc/build/nptl/pretty-printers')
end

source /path/to/glibc/source/pretty-printers/nptl-printers.py

You can check which printers are registered and enabled by issuing the
'info pretty-printer' gdb command. Printers should trigger automatically when
trying to print a variable of one of the types mentioned above.

The printers are architecture-independent, and were tested on an AMD64 running
Ubuntu 14.04 and an x86 VM running Fedora 24.

In order to work, the printers need to know the values of various flags that
are scattered throughout pthread.h and pthreadP.h as enums and #defines. Since
replicating these constants in the printers file itself would create a
maintenance burden, I wrote a script called gen-py-const.awk that Makerules uses
to extract the constants. This script is pretty much the same as gen-as-const.awk,
except it doesn't cast the constant values to 'long' and is thorougly documented.
The constants need only to be enumerated in a .pysym file, which is then referenced
by a Make variable called gen-py-const-headers.

As for the install directory, I discussed this with Mike Frysinger and Siddhesh
Poyarekar, and we agreed that it can be handled in a separate patch, and shouldn't
block merging of this one.

In addition, I've written a series of test cases for the pretty printers.
Each lock type (mutex, condvar and rwlock) has two test programs, one for itself
and other for its related 'attributes' object. Each test program in turn has a
PExpect-based Python script that drives gdb and compares its output to the
expected printer's. The tests run on the glibc host, which is assumed to have
both gdb and PExpect; if either is absent the tests will fail with code 77
(UNSUPPORTED). For cross-testing you should use cross-test-ssh.sh as test-wrapper.
I've tested the printers on both native builds and a cross build using a Beaglebone
Black running Debian, with the build system's filesystem shared with the board
through NFS.

Finally, I've written a README that explains all this and more.

	* INSTALL: Regenerated.
	* Makeconfig: Add comments and whitespace to make the control flow
	clearer.
	(+link-printers-tests, +link-pie-printers-tests, CFLAGS-printers-tests,
	installed-rtld-LDFLAGS, built-rtld-LDFLAGS, link-libc-rpath,
	link-libc-tests-after-rpath-link, link-libc-printers-tests): New.
	(rtld-LDFLAGS, rtld-tests-LDFLAGS, link-libc-tests-rpath-link,
	link-libc-tests): Use the new variables as required.
	* Makerules ($(py-const)): New rule.
	generated: Add $(py-const).
	* README.pretty-printers: New file.
	* Rules (tests-printers-programs, tests-printers-out, py-env): New.
	(others): Depend on $(py-const).
	(tests): Depend on $(tests-printers-programs) or $(tests-printers-out),
	as required.  Pass $(tests-printers) to merge-test-results.sh.
	* manual/install.texi: Add requirements for testing the pretty printers.
	* nptl/Makefile (gen-py-const-headers, pretty-printers, tests-printers,
	CFLAGS-test-mutexattr-printers.c CFLAGS-test-mutex-printers.c,
	CFLAGS-test-condattr-printers.c, CFLAGS-test-cond-printers.c,
	CFLAGS-test-rwlockattr-printers.c CFLAGS-test-rwlock-printers.c,
	tests-printers-libs): Define.
	* nptl/nptl-printers.py: New file.
	* nptl/nptl_lock_constants.pysym: Likewise.
	* nptl/test-cond-printers.c: Likewise.
	* nptl/test-cond-printers.py: Likewise.
	* nptl/test-condattr-printers.c: Likewise.
	* nptl/test-condattr-printers.py: Likewise.
	* nptl/test-mutex-printers.c: Likewise.
	* nptl/test-mutex-printers.py: Likewise.
	* nptl/test-mutexattr-printers.c: Likewise.
	* nptl/test-mutexattr-printers.py: Likewise.
	* nptl/test-rwlock-printers.c: Likewise.
	* nptl/test-rwlock-printers.py: Likewise.
	* nptl/test-rwlockattr-printers.c: Likewise.
	* nptl/test-rwlockattr-printers.py: Likewise.
	* scripts/gen-py-const.awk: Likewise.
	* scripts/test_printers_common.py: Likewise.
	* scripts/test_printers_exceptions.py: Likewise.

15 files changed, 1804 insertions, 0 deletions

diff --git a/nptl/Makefile b/nptl/Makefile
index 11588fe996..7ac9196975 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -312,6 +312,24 @@ gen-as-const-headers = pthread-errnos.sym \
 		       unwindbuf.sym \
 		       lowlevelrobustlock.sym pthread-pi-defines.sym
 
+gen-py-const-headers := nptl_lock_constants.pysym
+pretty-printers := nptl-printers.py
+tests-printers := test-mutexattr-printers test-mutex-printers \
+		  test-condattr-printers test-cond-printers \
+		  test-rwlockattr-printers test-rwlock-printers
+
+CFLAGS-test-mutexattr-printers.c := $(CFLAGS-printers-tests)
+CFLAGS-test-mutex-printers.c := $(CFLAGS-printers-tests)
+CFLAGS-test-condattr-printers.c := $(CFLAGS-printers-tests)
+CFLAGS-test-cond-printers.c := $(CFLAGS-printers-tests)
+CFLAGS-test-rwlockattr-printers.c := $(CFLAGS-printers-tests)
+CFLAGS-test-rwlock-printers.c := $(CFLAGS-printers-tests)
+
+ifeq ($(build-shared),yes)
+tests-printers-libs := $(shared-thread-library)
+else
+tests-printers-libs := $(static-thread-library)
+endif
 
 LDFLAGS-pthread.so = -Wl,--enable-new-dtags,-z,nodelete,-z,initfirst
 
diff --git a/nptl/nptl-printers.py b/nptl/nptl-printers.py
new file mode 100644
index 0000000000..e402f232c7
--- /dev/null
+++ b/nptl/nptl-printers.py
@@ -0,0 +1,633 @@
+# Pretty printers for the NPTL lock types.
+#
+# Copyright (C) 2016 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+"""This file contains the gdb pretty printers for the following types:
+
+    * pthread_mutex_t
+    * pthread_mutexattr_t
+    * pthread_cond_t
+    * pthread_condattr_t
+    * pthread_rwlock_t
+    * pthread_rwlockattr_t
+
+You can check which printers are registered and enabled by issuing the
+'info pretty-printer' gdb command.  Printers should trigger automatically when
+trying to print a variable of one of the types mentioned above.
+"""
+
+from __future__ import print_function
+
+import gdb
+import gdb.printing
+from nptl_lock_constants import *
+
+MUTEX_TYPES = {
+    PTHREAD_MUTEX_NORMAL: ('Type', 'Normal'),
+    PTHREAD_MUTEX_RECURSIVE: ('Type', 'Recursive'),
+    PTHREAD_MUTEX_ERRORCHECK: ('Type', 'Error check'),
+    PTHREAD_MUTEX_ADAPTIVE_NP: ('Type', 'Adaptive')
+}
+
+class MutexPrinter(object):
+    """Pretty printer for pthread_mutex_t."""
+
+    def __init__(self, mutex):
+        """Initialize the printer's internal data structures.
+
+        Args:
+            mutex: A gdb.value representing a pthread_mutex_t.
+        """
+
+        data = mutex['__data']
+        self.lock = data['__lock']
+        self.count = data['__count']
+        self.owner = data['__owner']
+        self.kind = data['__kind']
+        self.values = []
+        self.read_values()
+
+    def to_string(self):
+        """gdb API function.
+
+        This is called from gdb when we try to print a pthread_mutex_t.
+        """
+
+        return 'pthread_mutex_t'
+
+    def children(self):
+        """gdb API function.
+
+        This is called from gdb when we try to print a pthread_mutex_t.
+        """
+
+        return self.values
+
+    def read_values(self):
+        """Read the mutex's info and store it in self.values.
+
+        The data contained in self.values will be returned by the Iterator
+        created in self.children.
+        """
+
+        self.read_type()
+        self.read_status()
+        self.read_attributes()
+        self.read_misc_info()
+
+    def read_type(self):
+        """Read the mutex's type."""
+
+        mutex_type = self.kind & PTHREAD_MUTEX_KIND_MASK
+
+        # mutex_type must be casted to int because it's a gdb.Value
+        self.values.append(MUTEX_TYPES[int(mutex_type)])
+
+    def read_status(self):
+        """Read the mutex's status.
+
+        For architectures which support lock elision, this method reads
+        whether the mutex appears as locked in memory (i.e. it may show it as
+        unlocked even after calling pthread_mutex_lock).
+        """
+
+        if self.kind == PTHREAD_MUTEX_DESTROYED:
+            self.values.append(('Status', 'Destroyed'))
+        elif self.kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP:
+            self.read_status_robust()
+        else:
+            self.read_status_no_robust()
+
+    def read_status_robust(self):
+        """Read the status of a robust mutex.
+
+        In glibc robust mutexes are implemented in a very different way than
+        non-robust ones.  This method reads their locking status,
+        whether it may have waiters, their registered owner (if any),
+        whether the owner is alive or not, and the status of the state
+        they're protecting.
+        """
+
+        if self.lock == PTHREAD_MUTEX_UNLOCKED:
+            self.values.append(('Status', 'Unlocked'))
+        else:
+            if self.lock & FUTEX_WAITERS:
+                self.values.append(('Status', 'Locked, possibly with waiters'))
+            else:
+                self.values.append(('Status',
+                                    'Locked, possibly with no waiters'))
+
+            if self.lock & FUTEX_OWNER_DIED:
+                self.values.append(('Owner ID', '%d (dead)' % self.owner))
+            else:
+                self.values.append(('Owner ID', self.lock & FUTEX_TID_MASK))
+
+        if self.owner == PTHREAD_MUTEX_INCONSISTENT:
+            self.values.append(('State protected by this mutex',
+                                'Inconsistent'))
+        elif self.owner == PTHREAD_MUTEX_NOTRECOVERABLE:
+            self.values.append(('State protected by this mutex',
+                                'Not recoverable'))
+
+    def read_status_no_robust(self):
+        """Read the status of a non-robust mutex.
+
+        Read info on whether the mutex is locked, if it may have waiters
+        and its owner (if any).
+        """
+
+        lock_value = self.lock
+
+        if self.kind & PTHREAD_MUTEX_PRIO_PROTECT_NP:
+            lock_value &= ~(PTHREAD_MUTEX_PRIO_CEILING_MASK)
+
+        if lock_value == PTHREAD_MUTEX_UNLOCKED:
+            self.values.append(('Status', 'Unlocked'))
+        else:
+            if self.kind & PTHREAD_MUTEX_PRIO_INHERIT_NP:
+                waiters = self.lock & FUTEX_WAITERS
+                owner = self.lock & FUTEX_TID_MASK
+            else:
+                # Mutex protocol is PP or none
+                waiters = (self.lock != PTHREAD_MUTEX_LOCKED_NO_WAITERS)
+                owner = self.owner
+
+            if waiters:
+                self.values.append(('Status', 'Locked, possibly with waiters'))
+            else:
+                self.values.append(('Status',
+                                    'Locked, possibly with no waiters'))
+
+            self.values.append(('Owner ID', owner))
+
+    def read_attributes(self):
+        """Read the mutex's attributes."""
+
+        if self.kind != PTHREAD_MUTEX_DESTROYED:
+            if self.kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP:
+                self.values.append(('Robust', 'Yes'))
+            else:
+                self.values.append(('Robust', 'No'))
+
+            # In glibc, robust mutexes always have their pshared flag set to
+            # 'shared' regardless of what the pshared flag of their
+            # mutexattr was.  Therefore a robust mutex will act as shared
+            # even if it was initialized with a 'private' mutexattr.
+            if self.kind & PTHREAD_MUTEX_PSHARED_BIT:
+                self.values.append(('Shared', 'Yes'))
+            else:
+                self.values.append(('Shared', 'No'))
+
+            if self.kind & PTHREAD_MUTEX_PRIO_INHERIT_NP:
+                self.values.append(('Protocol', 'Priority inherit'))
+            elif self.kind & PTHREAD_MUTEX_PRIO_PROTECT_NP:
+                prio_ceiling = ((self.lock & PTHREAD_MUTEX_PRIO_CEILING_MASK)
+                                >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT)
+
+                self.values.append(('Protocol', 'Priority protect'))
+                self.values.append(('Priority ceiling', prio_ceiling))
+            else:
+                # PTHREAD_PRIO_NONE
+                self.values.append(('Protocol', 'None'))
+
+    def read_misc_info(self):
+        """Read miscellaneous info on the mutex.
+
+        For now this reads the number of times a recursive mutex was locked
+        by the same thread.
+        """
+
+        mutex_type = self.kind & PTHREAD_MUTEX_KIND_MASK
+
+        if mutex_type == PTHREAD_MUTEX_RECURSIVE and self.count > 1:
+            self.values.append(('Times locked recursively', self.count))
+
+class MutexAttributesPrinter(object):
+    """Pretty printer for pthread_mutexattr_t.
+
+    In the NPTL this is a type that's always casted to struct pthread_mutexattr
+    which has a single 'mutexkind' field containing the actual attributes.
+    """
+
+    def __init__(self, mutexattr):
+        """Initialize the printer's internal data structures.
+
+        Args:
+            mutexattr: A gdb.value representing a pthread_mutexattr_t.
+        """
+
+        self.values = []
+
+        try:
+            mutexattr_struct = gdb.lookup_type('struct pthread_mutexattr')
+            self.mutexattr = mutexattr.cast(mutexattr_struct)['mutexkind']
+            self.read_values()
+        except gdb.error:
+            # libpthread doesn't have debug symbols, thus we can't find the
+            # real struct type.  Just print the union members.
+            self.values.append(('__size', mutexattr['__size']))
+            self.values.append(('__align', mutexattr['__align']))
+
+    def to_string(self):
+        """gdb API function.
+
+        This is called from gdb when we try to print a pthread_mutexattr_t.
+        """
+
+        return 'pthread_mutexattr_t'
+
+    def children(self):
+        """gdb API function.
+
+        This is called from gdb when we try to print a pthread_mutexattr_t.
+        """
+
+        return self.values
+
+    def read_values(self):
+        """Read the mutexattr's info and store it in self.values.
+
+        The data contained in self.values will be returned by the Iterator
+        created in self.children.
+        """
+
+        mutexattr_type = (self.mutexattr
+                          & ~PTHREAD_MUTEXATTR_FLAG_BITS
+                          & ~PTHREAD_MUTEX_NO_ELISION_NP)
+
+        # mutexattr_type must be casted to int because it's a gdb.Value
+        self.values.append(MUTEX_TYPES[int(mutexattr_type)])
+
+        if self.mutexattr & PTHREAD_MUTEXATTR_FLAG_ROBUST:
+            self.values.append(('Robust', 'Yes'))
+        else:
+            self.values.append(('Robust', 'No'))
+
+        if self.mutexattr & PTHREAD_MUTEXATTR_FLAG_PSHARED:
+            self.values.append(('Shared', 'Yes'))
+        else:
+            self.values.append(('Shared', 'No'))
+
+        protocol = ((self.mutexattr & PTHREAD_MUTEXATTR_PROTOCOL_MASK) >>
+                    PTHREAD_MUTEXATTR_PROTOCOL_SHIFT)
+
+        if protocol == PTHREAD_PRIO_NONE:
+            self.values.append(('Protocol', 'None'))
+        elif protocol == PTHREAD_PRIO_INHERIT:
+            self.values.append(('Protocol', 'Priority inherit'))
+        elif protocol == PTHREAD_PRIO_PROTECT:
+            self.values.append(('Protocol', 'Priority protect'))
+
+CLOCK_IDS = {
+    CLOCK_REALTIME: 'CLOCK_REALTIME',
+    CLOCK_MONOTONIC: 'CLOCK_MONOTONIC',
+    CLOCK_PROCESS_CPUTIME_ID: 'CLOCK_PROCESS_CPUTIME_ID',
+    CLOCK_THREAD_CPUTIME_ID: 'CLOCK_THREAD_CPUTIME_ID',
+    CLOCK_MONOTONIC_RAW: 'CLOCK_MONOTONIC_RAW',
+    CLOCK_REALTIME_COARSE: 'CLOCK_REALTIME_COARSE',
+    CLOCK_MONOTONIC_COARSE: 'CLOCK_MONOTONIC_COARSE'
+}
+
+class ConditionVariablePrinter(object):
+    """Pretty printer for pthread_cond_t."""
+
+    def __init__(self, cond):
+        """Initialize the printer's internal data structures.
+
+        Args:
+            cond: A gdb.value representing a pthread_cond_t.
+        """
+
+        # Since PTHREAD_COND_SHARED is an integer, we need to cast it to void *
+        # to be able to compare it to the condvar's __data.__mutex member.
+        #
+        # While it looks like self.shared_value should be a class variable,
+        # that would result in it having an incorrect size if we're loading
+        # these printers through .gdbinit for a 64-bit objfile in AMD64.
+        # This is because gdb initially assumes the pointer size to be 4 bytes,
+        # and only sets it to 8 after loading the 64-bit objfiles.  Since
+        # .gdbinit runs before any objfiles are loaded, this would effectively
+        # make self.shared_value have a size of 4, thus breaking later
+        # comparisons with pointers whose types are looked up at runtime.
+        void_ptr_type = gdb.lookup_type('void').pointer()
+        self.shared_value = gdb.Value(PTHREAD_COND_SHARED).cast(void_ptr_type)
+
+        data = cond['__data']
+        self.total_seq = data['__total_seq']
+        self.mutex = data['__mutex']
+        self.nwaiters = data['__nwaiters']
+        self.values = []
+
+        self.read_values()
+
+    def to_string(self):
+        """gdb API function.
+
+        This is called from gdb when we try to print a pthread_cond_t.
+        """
+
+        return 'pthread_cond_t'
+
+    def children(self):
+        """gdb API function.
+
+        This is called from gdb when we try to print a pthread_cond_t.
+        """
+
+        return self.values
+
+    def read_values(self):
+        """Read the condvar's info and store it in self.values.
+
+        The data contained in self.values will be returned by the Iterator
+        created in self.children.
+        """
+
+        self.read_status()
+        self.read_attributes()
+        self.read_mutex_info()
+
+    def read_status(self):
+        """Read the status of the condvar.
+
+        This method reads whether the condvar is destroyed and how many threads
+        are waiting for it.
+        """
+
+        if self.total_seq == PTHREAD_COND_DESTROYED:
+            self.values.append(('Status', 'Destroyed'))
+
+        self.values.append(('Threads waiting for this condvar',
+                            self.nwaiters >> COND_NWAITERS_SHIFT))
+
+    def read_attributes(self):
+        """Read the condvar's attributes."""
+
+        clock_id = self.nwaiters & ((1 << COND_NWAITERS_SHIFT) - 1)
+
+        # clock_id must be casted to int because it's a gdb.Value
+        self.values.append(('Clock ID', CLOCK_IDS[int(clock_id)]))
+
+        shared = (self.mutex == self.shared_value)
+
+        if shared:
+            self.values.append(('Shared', 'Yes'))
+        else:
+            self.values.append(('Shared', 'No'))
+
+    def read_mutex_info(self):
+        """Read the data of the mutex this condvar is bound to.
+
+        A pthread_cond_t's __data.__mutex member is a void * which
+        must be casted to pthread_mutex_t *.  For shared condvars, this
+        member isn't recorded and has a special value instead.
+        """
+
+        if self.mutex and self.mutex != self.shared_value:
+            mutex_type = gdb.lookup_type('pthread_mutex_t')
+            mutex = self.mutex.cast(mutex_type.pointer()).dereference()
+
+            self.values.append(('Mutex', mutex))
+
+class ConditionVariableAttributesPrinter(object):
+    """Pretty printer for pthread_condattr_t.
+
+    In the NPTL this is a type that's always casted to struct pthread_condattr,
+    which has a single 'value' field containing the actual attributes.
+    """
+
+    def __init__(self, condattr):
+        """Initialize the printer's internal data structures.
+
+        Args:
+            condattr: A gdb.value representing a pthread_condattr_t.
+        """
+
+        self.values = []
+
+        try:
+            condattr_struct = gdb.lookup_type('struct pthread_condattr')
+            self.condattr = condattr.cast(condattr_struct)['value']
+            self.read_values()
+        except gdb.error:
+            # libpthread doesn't have debug symbols, thus we can't find the
+            # real struct type.  Just print the union members.
+            self.values.append(('__size', condattr['__size']))
+            self.values.append(('__align', condattr['__align']))
+
+    def to_string(self):
+        """gdb API function.
+
+        This is called from gdb when we try to print a pthread_condattr_t.
+        """
+
+        return 'pthread_condattr_t'
+
+    def children(self):
+        """gdb API function.
+
+        This is called from gdb when we try to print a pthread_condattr_t.
+        """
+
+        return self.values
+
+    def read_values(self):
+        """Read the condattr's info and store it in self.values.
+
+        The data contained in self.values will be returned by the Iterator
+        created in self.children.
+        """
+
+        clock_id = self.condattr & ((1 << COND_NWAITERS_SHIFT) - 1)
+
+        # clock_id must be casted to int because it's a gdb.Value
+        self.values.append(('Clock ID', CLOCK_IDS[int(clock_id)]))
+
+        if self.condattr & 1:
+            self.values.append(('Shared', 'Yes'))
+        else:
+            self.values.append(('Shared', 'No'))
+
+class RWLockPrinter(object):
+    """Pretty printer for pthread_rwlock_t."""
+
+    def __init__(self, rwlock):
+        """Initialize the printer's internal data structures.
+
+        Args:
+            rwlock: A gdb.value representing a pthread_rwlock_t.
+        """
+
+        data = rwlock['__data']
+        self.readers = data['__nr_readers']
+        self.queued_readers = data['__nr_readers_queued']
+        self.queued_writers = data['__nr_writers_queued']
+        self.writer_id = data['__writer']
+        self.shared = data['__shared']
+        self.prefers_writers = data['__flags']
+        self.values = []
+        self.read_values()
+
+    def to_string(self):
+        """gdb API function.
+
+        This is called from gdb when we try to print a pthread_rwlock_t.
+        """
+
+        return 'pthread_rwlock_t'
+
+    def children(self):
+        """gdb API function.
+
+        This is called from gdb when we try to print a pthread_rwlock_t.
+        """
+
+        return self.values
+
+    def read_values(self):
+        """Read the rwlock's info and store it in self.values.
+
+        The data contained in self.values will be returned by the Iterator
+        created in self.children.
+        """
+
+        self.read_status()
+        self.read_attributes()
+
+    def read_status(self):
+        """Read the status of the rwlock."""
+
+        # Right now pthread_rwlock_destroy doesn't do anything, so there's no
+        # way to check if an rwlock is destroyed.
+
+        if self.writer_id:
+            self.values.append(('Status', 'Locked (Write)'))
+            self.values.append(('Writer ID', self.writer_id))
+        elif self.readers:
+            self.values.append(('Status', 'Locked (Read)'))
+            self.values.append(('Readers', self.readers))
+        else:
+            self.values.append(('Status', 'Unlocked'))
+
+        self.values.append(('Queued readers', self.queued_readers))
+        self.values.append(('Queued writers', self.queued_writers))
+
+    def read_attributes(self):
+        """Read the attributes of the rwlock."""
+
+        if self.shared:
+            self.values.append(('Shared', 'Yes'))
+        else:
+            self.values.append(('Shared', 'No'))
+
+        if self.prefers_writers:
+            self.values.append(('Prefers', 'Writers'))
+        else:
+            self.values.append(('Prefers', 'Readers'))
+
+class RWLockAttributesPrinter(object):
+    """Pretty printer for pthread_rwlockattr_t.
+
+    In the NPTL this is a type that's always casted to
+    struct pthread_rwlockattr, which has two fields ('lockkind' and 'pshared')
+    containing the actual attributes.
+    """
+
+    def __init__(self, rwlockattr):
+        """Initialize the printer's internal data structures.
+
+        Args:
+            rwlockattr: A gdb.value representing a pthread_rwlockattr_t.
+        """
+
+        self.values = []
+
+        try:
+            rwlockattr_struct = gdb.lookup_type('struct pthread_rwlockattr')
+            self.rwlockattr = rwlockattr.cast(rwlockattr_struct)
+            self.read_values()
+        except gdb.error:
+            # libpthread doesn't have debug symbols, thus we can't find the
+            # real struct type.  Just print the union members.
+            self.values.append(('__size', rwlockattr['__size']))
+            self.values.append(('__align', rwlockattr['__align']))
+
+    def to_string(self):
+        """gdb API function.
+
+        This is called from gdb when we try to print a pthread_rwlockattr_t.
+        """
+
+        return 'pthread_rwlockattr_t'
+
+    def children(self):
+        """gdb API function.
+
+        This is called from gdb when we try to print a pthread_rwlockattr_t.
+        """
+
+        return self.values
+
+    def read_values(self):
+        """Read the rwlockattr's info and store it in self.values.
+
+        The data contained in self.values will be returned by the Iterator
+        created in self.children.
+        """
+
+        rwlock_type = self.rwlockattr['lockkind']
+        shared = self.rwlockattr['pshared']
+
+        if shared == PTHREAD_PROCESS_SHARED:
+            self.values.append(('Shared', 'Yes'))
+        else:
+            # PTHREAD_PROCESS_PRIVATE
+            self.values.append(('Shared', 'No'))
+
+        if (rwlock_type == PTHREAD_RWLOCK_PREFER_READER_NP or
+            rwlock_type == PTHREAD_RWLOCK_PREFER_WRITER_NP):
+            # This is a known bug.  Using PTHREAD_RWLOCK_PREFER_WRITER_NP will
+            # still make the rwlock prefer readers.
+            self.values.append(('Prefers', 'Readers'))
+        elif rwlock_type == PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP:
+            self.values.append(('Prefers', 'Writers'))
+
+def register(objfile):
+    """Register the pretty printers within the given objfile."""
+
+    printer = gdb.printing.RegexpCollectionPrettyPrinter('glibc-pthread-locks')
+
+    printer.add_printer('pthread_mutex_t', r'^pthread_mutex_t$',
+                        MutexPrinter)
+    printer.add_printer('pthread_mutexattr_t', r'^pthread_mutexattr_t$',
+                        MutexAttributesPrinter)
+    printer.add_printer('pthread_cond_t', r'^pthread_cond_t$',
+                        ConditionVariablePrinter)
+    printer.add_printer('pthread_condattr_t', r'^pthread_condattr_t$',
+                        ConditionVariableAttributesPrinter)
+    printer.add_printer('pthread_rwlock_t', r'^pthread_rwlock_t$',
+                        RWLockPrinter)
+    printer.add_printer('pthread_rwlockattr_t', r'^pthread_rwlockattr_t$',
+                        RWLockAttributesPrinter)
+
+    if objfile == None:
+        objfile = gdb
+
+    gdb.printing.register_pretty_printer(objfile, printer)
+
+register(gdb.current_objfile())
diff --git a/nptl/nptl_lock_constants.pysym b/nptl/nptl_lock_constants.pysym
new file mode 100644
index 0000000000..303ec61213
--- /dev/null
+++ b/nptl/nptl_lock_constants.pysym
@@ -0,0 +1,75 @@
+#include <pthreadP.h>
+
+-- Mutex types
+PTHREAD_MUTEX_KIND_MASK          PTHREAD_MUTEX_KIND_MASK_NP
+PTHREAD_MUTEX_NORMAL
+PTHREAD_MUTEX_RECURSIVE          PTHREAD_MUTEX_RECURSIVE_NP
+PTHREAD_MUTEX_ERRORCHECK         PTHREAD_MUTEX_ERRORCHECK_NP
+PTHREAD_MUTEX_ADAPTIVE_NP
+
+-- Mutex status
+-- These are hardcoded all over the code; there are no enums/macros for them.
+PTHREAD_MUTEX_DESTROYED         -1
+PTHREAD_MUTEX_UNLOCKED           0
+PTHREAD_MUTEX_LOCKED_NO_WAITERS  1
+
+-- For robust mutexes
+PTHREAD_MUTEX_INCONSISTENT
+PTHREAD_MUTEX_NOTRECOVERABLE
+FUTEX_OWNER_DIED
+
+-- For robust and PI mutexes
+FUTEX_WAITERS
+FUTEX_TID_MASK
+
+-- Mutex attributes
+PTHREAD_MUTEX_ROBUST_NORMAL_NP
+PTHREAD_MUTEX_PRIO_INHERIT_NP
+PTHREAD_MUTEX_PRIO_PROTECT_NP
+PTHREAD_MUTEX_PSHARED_BIT
+PTHREAD_MUTEX_PRIO_CEILING_SHIFT
+PTHREAD_MUTEX_PRIO_CEILING_MASK
+
+-- Mutex attribute flags
+PTHREAD_MUTEXATTR_PROTOCOL_SHIFT
+PTHREAD_MUTEXATTR_PROTOCOL_MASK
+PTHREAD_MUTEXATTR_PRIO_CEILING_MASK
+PTHREAD_MUTEXATTR_FLAG_ROBUST
+PTHREAD_MUTEXATTR_FLAG_PSHARED
+PTHREAD_MUTEXATTR_FLAG_BITS
+PTHREAD_MUTEX_NO_ELISION_NP
+
+-- Priority protocols
+PTHREAD_PRIO_NONE
+PTHREAD_PRIO_INHERIT
+PTHREAD_PRIO_PROTECT
+
+-- These values are hardcoded as well:
+-- Value of __mutex for shared condvars.
+PTHREAD_COND_SHARED             (void *)~0l
+
+-- Value of __total_seq for destroyed condvars.
+PTHREAD_COND_DESTROYED          -1ull
+
+-- __nwaiters encodes the number of threads waiting on a condvar
+-- and the clock ID.
+-- __nwaiters >> COND_NWAITERS_SHIFT gives us the number of waiters.
+COND_NWAITERS_SHIFT
+
+-- Condvar clock IDs
+CLOCK_REALTIME
+CLOCK_MONOTONIC
+CLOCK_PROCESS_CPUTIME_ID
+CLOCK_THREAD_CPUTIME_ID
+CLOCK_MONOTONIC_RAW
+CLOCK_REALTIME_COARSE
+CLOCK_MONOTONIC_COARSE
+
+-- Rwlock attributes
+PTHREAD_RWLOCK_PREFER_READER_NP
+PTHREAD_RWLOCK_PREFER_WRITER_NP
+PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP
+
+-- 'Shared' attribute values
+PTHREAD_PROCESS_PRIVATE
+PTHREAD_PROCESS_SHARED
diff --git a/nptl/test-cond-printers.c b/nptl/test-cond-printers.c
new file mode 100644
index 0000000000..0f2a5f4827
--- /dev/null
+++ b/nptl/test-cond-printers.c
@@ -0,0 +1,57 @@
+/* Helper program for testing the pthread_cond_t pretty printer.
+
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Keep the calls to the pthread_* functions on separate lines to make it easy
+   to advance through the program using the gdb 'next' command.  */
+
+#include <time.h>
+#include <pthread.h>
+
+#define PASS 0
+#define FAIL 1
+
+static int test_status_destroyed (pthread_cond_t *condvar);
+
+int
+main (void)
+{
+  pthread_cond_t condvar;
+  pthread_condattr_t attr;
+  int result = FAIL;
+
+  if (pthread_condattr_init (&attr) == 0
+      && test_status_destroyed (&condvar) == PASS)
+    result = PASS;
+  /* Else, one of the pthread_cond* functions failed.  */
+
+  return result;
+}
+
+/* Initializes CONDVAR, then destroys it.  */
+static int
+test_status_destroyed (pthread_cond_t *condvar)
+{
+  int result = FAIL;
+
+  if (pthread_cond_init (condvar, NULL) == 0
+      && pthread_cond_destroy (condvar) == 0)
+    result = PASS; /* Test status (destroyed).  */
+
+  return result;
+}
diff --git a/nptl/test-cond-printers.py b/nptl/test-cond-printers.py
new file mode 100644
index 0000000000..af0e12eb97
--- /dev/null
+++ b/nptl/test-cond-printers.py
@@ -0,0 +1,50 @@
+# Common tests for the ConditionVariablePrinter class.
+#
+# Copyright (C) 2016 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+import sys
+
+from test_printers_common import *
+
+test_source = sys.argv[1]
+test_bin = sys.argv[2]
+printer_files = sys.argv[3:]
+printer_names = ['global glibc-pthread-locks']
+
+try:
+    init_test(test_bin, printer_files, printer_names)
+    go_to_main()
+
+    var = 'condvar'
+    to_string = 'pthread_cond_t'
+
+    break_at(test_source, 'Test status (destroyed)')
+    continue_cmd() # Go to test_status_destroyed
+    test_printer(var, to_string, {'Status': 'Destroyed'})
+
+    continue_cmd() # Exit
+
+except (NoLineError, pexpect.TIMEOUT) as exception:
+    print('Error: {0}'.format(exception))
+    result = FAIL
+
+else:
+    print('Test succeeded.')
+    result = PASS
+
+exit(result)
diff --git a/nptl/test-condattr-printers.c b/nptl/test-condattr-printers.c
new file mode 100644
index 0000000000..4db4098827
--- /dev/null
+++ b/nptl/test-condattr-printers.c
@@ -0,0 +1,94 @@
+/* Helper program for testing the pthread_cond_t and pthread_condattr_t
+   pretty printers.
+
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Keep the calls to the pthread_* functions on separate lines to make it easy
+   to advance through the program using the gdb 'next' command.  */
+
+#include <time.h>
+#include <pthread.h>
+
+#define PASS 0
+#define FAIL 1
+
+static int condvar_reinit (pthread_cond_t *condvar,
+			   const pthread_condattr_t *attr);
+static int test_setclock (pthread_cond_t *condvar, pthread_condattr_t *attr);
+static int test_setpshared (pthread_cond_t *condvar, pthread_condattr_t *attr);
+
+/* Need these so we don't have lines longer than 79 chars.  */
+#define SET_SHARED(attr, shared) pthread_condattr_setpshared (attr, shared)
+
+int
+main (void)
+{
+  pthread_cond_t condvar;
+  pthread_condattr_t attr;
+  int result = FAIL;
+
+  if (pthread_condattr_init (&attr) == 0
+      && pthread_cond_init (&condvar, NULL) == 0
+      && test_setclock (&condvar, &attr) == PASS
+      && test_setpshared (&condvar, &attr) == PASS)
+    result = PASS;
+  /* Else, one of the pthread_cond* functions failed.  */
+
+  return result;
+}
+
+/* Destroys CONDVAR and re-initializes it using ATTR.  */
+static int
+condvar_reinit (pthread_cond_t *condvar, const pthread_condattr_t *attr)
+{
+  int result = FAIL;
+
+  if (pthread_cond_destroy (condvar) == 0
+      && pthread_cond_init (condvar, attr) == 0)
+    result = PASS;
+
+  return result;
+}
+
+/* Tests setting the clock ID attribute.  */
+static int
+test_setclock (pthread_cond_t *condvar, pthread_condattr_t *attr)
+{
+  int result = FAIL;
+
+  if (pthread_condattr_setclock (attr, CLOCK_REALTIME) == 0 /* Set clock.  */
+      && condvar_reinit (condvar, attr) == PASS)
+    result = PASS;
+
+  return result;
+}
+
+/* Tests setting whether the condvar can be shared between processes.  */
+static int
+test_setpshared (pthread_cond_t *condvar, pthread_condattr_t *attr)
+{
+  int result = FAIL;
+
+  if (SET_SHARED (attr, PTHREAD_PROCESS_SHARED) == 0 /* Set shared.  */
+      && condvar_reinit (condvar, attr) == PASS
+      && SET_SHARED (attr, PTHREAD_PROCESS_PRIVATE) == 0
+      && condvar_reinit (condvar, attr) == PASS)
+    result = PASS;
+
+  return result;
+}
diff --git a/nptl/test-condattr-printers.py b/nptl/test-condattr-printers.py
new file mode 100644
index 0000000000..7ea01db158
--- /dev/null
+++ b/nptl/test-condattr-printers.py
@@ -0,0 +1,71 @@
+# Common tests for the ConditionVariablePrinter and
+# ConditionVariableAttributesPrinter classes.
+#
+# Copyright (C) 2016 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+import sys
+
+from test_printers_common import *
+
+test_source = sys.argv[1]
+test_bin = sys.argv[2]
+printer_files = sys.argv[3:]
+printer_names = ['global glibc-pthread-locks']
+
+try:
+    init_test(test_bin, printer_files, printer_names)
+    go_to_main()
+
+    check_debug_symbol('struct pthread_condattr')
+
+    condvar_var = 'condvar'
+    condvar_to_string = 'pthread_cond_t'
+
+    attr_var = 'attr'
+    attr_to_string = 'pthread_condattr_t'
+
+    break_at(test_source, 'Set clock')
+    continue_cmd() # Go to test_setclock
+    next_cmd(2)
+    test_printer(condvar_var, condvar_to_string, {'Clock ID': 'CLOCK_REALTIME'})
+    test_printer(attr_var, attr_to_string, {'Clock ID': 'CLOCK_REALTIME'})
+
+    break_at(test_source, 'Set shared')
+    continue_cmd() # Go to test_setpshared
+    next_cmd(2)
+    test_printer(condvar_var, condvar_to_string, {'Shared': 'Yes'})
+    test_printer(attr_var, attr_to_string, {'Shared': 'Yes'})
+    next_cmd(2)
+    test_printer(condvar_var, condvar_to_string, {'Shared': 'No'})
+    test_printer(attr_var, attr_to_string, {'Shared': 'No'})
+
+    continue_cmd() # Exit
+
+except (NoLineError, pexpect.TIMEOUT) as exception:
+    print('Error: {0}'.format(exception))
+    result = FAIL
+
+except DebugError as exception:
+    print(exception)
+    result = UNSUPPORTED
+
+else:
+    print('Test succeeded.')
+    result = PASS
+
+exit(result)
diff --git a/nptl/test-mutex-printers.c b/nptl/test-mutex-printers.c
new file mode 100644
index 0000000000..b973e82840
--- /dev/null
+++ b/nptl/test-mutex-printers.c
@@ -0,0 +1,151 @@
+/* Helper program for testing the pthread_mutex_t pretty printer.
+
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Keep the calls to the pthread_* functions on separate lines to make it easy
+   to advance through the program using the gdb 'next' command.  */
+
+#include <stdlib.h>
+#include <errno.h>
+#include <pthread.h>
+
+#define PASS 0
+#define FAIL 1
+
+static int test_status_destroyed (pthread_mutex_t *mutex);
+static int test_status_no_robust (pthread_mutex_t *mutex,
+				  pthread_mutexattr_t *attr);
+static int test_status_robust (pthread_mutex_t *mutex,
+			       pthread_mutexattr_t *attr);
+static int test_locking_state_robust (pthread_mutex_t *mutex);
+static void *thread_func (void *arg);
+static int test_recursive_locks (pthread_mutex_t *mutex,
+				 pthread_mutexattr_t *attr);
+
+int
+main (void)
+{
+  pthread_mutex_t mutex;
+  pthread_mutexattr_t attr;
+  int result = FAIL;
+
+  if (pthread_mutexattr_init (&attr) == 0
+      && test_status_destroyed (&mutex) == PASS
+      && test_status_no_robust (&mutex, &attr) == PASS
+      && test_status_robust (&mutex, &attr) == PASS
+      && test_recursive_locks (&mutex, &attr) == PASS)
+    result = PASS;
+  /* Else, one of the pthread_mutex* functions failed.  */
+
+  return result;
+}
+
+/* Initializes MUTEX, then destroys it.  */
+static int
+test_status_destroyed (pthread_mutex_t *mutex)
+{
+  int result = FAIL;
+
+  if (pthread_mutex_init (mutex, NULL) == 0
+      && pthread_mutex_destroy (mutex) == 0)
+    result = PASS; /* Test status (destroyed).  */
+
+  return result;
+}
+
+/* Tests locking of non-robust mutexes.  */
+static int
+test_status_no_robust (pthread_mutex_t *mutex, pthread_mutexattr_t *attr)
+{
+  int result = FAIL;
+
+  if (pthread_mutexattr_setrobust (attr, PTHREAD_MUTEX_STALLED) == 0
+      && pthread_mutex_init (mutex, attr) == 0
+      && pthread_mutex_lock (mutex) == 0 /* Test status (non-robust).  */
+      && pthread_mutex_unlock (mutex) == 0
+      && pthread_mutex_destroy (mutex) == 0)
+    result = PASS;
+
+  return result;
+}
+
+/* Tests locking of robust mutexes.  */
+static int
+test_status_robust (pthread_mutex_t *mutex, pthread_mutexattr_t *attr)
+{
+  int result = FAIL;
+
+  if (pthread_mutexattr_setrobust (attr, PTHREAD_MUTEX_ROBUST) == 0
+      && pthread_mutex_init (mutex, attr) == 0
+      && test_locking_state_robust (mutex) == PASS /* Test status (robust).  */
+      && pthread_mutex_destroy (mutex) == 0)
+    result = PASS;
+
+  return result;
+}
+
+/* Tests locking and state corruption of robust mutexes.  We'll mark it as
+   inconsistent, then not recoverable.  */
+static int
+test_locking_state_robust (pthread_mutex_t *mutex)
+{
+  int result = FAIL;
+  pthread_t thread;
+
+  if (pthread_create (&thread, NULL, thread_func, mutex) == 0 /* Create.  */
+      && pthread_join (thread, NULL) == 0
+      && pthread_mutex_lock (mutex) == EOWNERDEAD /* Test locking (robust).  */
+      && pthread_mutex_unlock (mutex) == 0)
+    result = PASS;
+
+  return result;
+}
+
+/* Function to be called by the child thread when testing robust mutexes.  */
+static void *
+thread_func (void *arg)
+{
+  pthread_mutex_t *mutex = (pthread_mutex_t *)arg;
+
+  if (pthread_mutex_lock (mutex) != 0) /* Thread function.  */
+    exit (FAIL);
+
+  /* Thread terminates without unlocking the mutex, thus marking it as
+     inconsistent.  */
+  return NULL;
+}
+
+/* Tests locking the mutex multiple times in a row.  */
+static int
+test_recursive_locks (pthread_mutex_t *mutex, pthread_mutexattr_t *attr)
+{
+  int result = FAIL;
+
+  if (pthread_mutexattr_settype (attr, PTHREAD_MUTEX_RECURSIVE) == 0
+      && pthread_mutex_init (mutex, attr) == 0
+      && pthread_mutex_lock (mutex) == 0
+      && pthread_mutex_lock (mutex) == 0
+      && pthread_mutex_lock (mutex) == 0 /* Test recursive locks.  */
+      && pthread_mutex_unlock (mutex) == 0
+      && pthread_mutex_unlock (mutex) == 0
+      && pthread_mutex_unlock (mutex) == 0
+      && pthread_mutex_destroy (mutex) == 0)
+    result = PASS;
+
+  return result;
+}
diff --git a/nptl/test-mutex-printers.py b/nptl/test-mutex-printers.py
new file mode 100644
index 0000000000..7f542adcd7
--- /dev/null
+++ b/nptl/test-mutex-printers.py
@@ -0,0 +1,97 @@
+# Tests for the MutexPrinter class.
+#
+# Copyright (C) 2016 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+import sys
+
+from test_printers_common import *
+
+test_source = sys.argv[1]
+test_bin = sys.argv[2]
+printer_files = sys.argv[3:]
+printer_names = ['global glibc-pthread-locks']
+
+try:
+    init_test(test_bin, printer_files, printer_names)
+    go_to_main()
+
+    var = 'mutex'
+    to_string = 'pthread_mutex_t'
+
+    break_at(test_source, 'Test status (destroyed)')
+    continue_cmd() # Go to test_status_destroyed
+    test_printer(var, to_string, {'Status': 'Destroyed'})
+
+    break_at(test_source, 'Test status (non-robust)')
+    continue_cmd() # Go to test_status_no_robust
+    test_printer(var, to_string, {'Status': 'Unlocked'})
+    next_cmd()
+    thread_id = get_current_thread_lwpid()
+    test_printer(var, to_string, {'Status': 'Locked, possibly with no waiters',
+                                  'Owner ID': thread_id})
+
+    break_at(test_source, 'Test status (robust)')
+    continue_cmd() # Go to test_status_robust
+    test_printer(var, to_string, {'Status': 'Unlocked'})
+
+    # We'll now test the robust mutex locking states.  We'll create a new
+    # thread that will lock a robust mutex and exit without unlocking it.
+    break_at(test_source, 'Create')
+    continue_cmd() # Go to test_locking_state_robust
+    # Set a breakpoint for the new thread to hit.
+    break_at(test_source, 'Thread function')
+    continue_cmd()
+    # By now the new thread is created and has hit its breakpoint.
+    set_scheduler_locking(True)
+    parent = 1
+    child = 2
+    select_thread(child)
+    child_id = get_current_thread_lwpid()
+    # We've got the new thread's ID.
+    select_thread(parent)
+    # Make the new thread finish its function while we wait.
+    continue_cmd(thread=child)
+    # The new thread should be dead by now.
+    break_at(test_source, 'Test locking (robust)')
+    continue_cmd()
+    test_printer(var, to_string, {'Owner ID': r'{0} \(dead\)'.format(child_id)})
+    # Try to lock and unlock the mutex.
+    next_cmd()
+    test_printer(var, to_string, {'Owner ID': thread_id,
+                           'State protected by this mutex': 'Inconsistent'})
+    next_cmd()
+    test_printer(var, to_string, {'Status': 'Unlocked',
+                        'State protected by this mutex': 'Not recoverable'})
+    set_scheduler_locking(False)
+
+    break_at(test_source, 'Test recursive locks')
+    continue_cmd() # Go to test_recursive_locks
+    test_printer(var, to_string, {'Times locked recursively': '2'})
+    next_cmd()
+    test_printer(var, to_string, {'Times locked recursively': '3'})
+    continue_cmd() # Exit
+
+except (NoLineError, pexpect.TIMEOUT) as exception:
+    print('Error: {0}'.format(exception))
+    result = FAIL
+
+else:
+    print('Test succeeded.')
+    result = PASS
+
+exit(result)
diff --git a/nptl/test-mutexattr-printers.c b/nptl/test-mutexattr-printers.c
new file mode 100644
index 0000000000..9ecfff76c3
--- /dev/null
+++ b/nptl/test-mutexattr-printers.c
@@ -0,0 +1,144 @@
+/* Helper program for testing the pthread_mutex_t and pthread_mutexattr_t
+   pretty printers.
+
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Keep the calls to the pthread_* functions on separate lines to make it easy
+   to advance through the program using the gdb 'next' command.  */
+
+#include <pthread.h>
+
+#define PASS 0
+#define FAIL 1
+#define PRIOCEILING 42
+
+/* Need these so we don't have lines longer than 79 chars.  */
+#define SET_TYPE(attr, type) pthread_mutexattr_settype (attr, type)
+#define SET_ROBUST(attr, robust) pthread_mutexattr_setrobust (attr, robust)
+#define SET_SHARED(attr, shared) pthread_mutexattr_setpshared (attr, shared)
+#define SET_PROTOCOL(attr, protocol) \
+	pthread_mutexattr_setprotocol (attr, protocol)
+#define SET_PRIOCEILING(mutex, prioceiling, old_ceiling) \
+	pthread_mutex_setprioceiling (mutex, prioceiling, old_ceiling)
+
+static int mutex_reinit (pthread_mutex_t *mutex,
+			 const pthread_mutexattr_t *attr);
+static int test_settype (pthread_mutex_t *mutex, pthread_mutexattr_t *attr);
+static int test_setrobust (pthread_mutex_t *mutex, pthread_mutexattr_t *attr);
+static int test_setpshared (pthread_mutex_t *mutex, pthread_mutexattr_t *attr);
+static int test_setprotocol (pthread_mutex_t *mutex,
+			     pthread_mutexattr_t *attr);
+
+int
+main (void)
+{
+  pthread_mutex_t mutex;
+  pthread_mutexattr_t attr;
+  int result = FAIL;
+
+  if (pthread_mutexattr_init (&attr) == 0
+      && pthread_mutex_init (&mutex, NULL) == 0
+      && test_settype (&mutex, &attr) == PASS
+      && test_setrobust (&mutex, &attr) == PASS
+      && test_setpshared (&mutex, &attr) == PASS
+      && test_setprotocol (&mutex, &attr) == PASS)
+    result = PASS;
+  /* Else, one of the pthread_mutex* functions failed.  */
+
+  return result;
+}
+
+/* Destroys MUTEX and re-initializes it using ATTR.  */
+static int
+mutex_reinit (pthread_mutex_t *mutex, const pthread_mutexattr_t *attr)
+{
+  int result = FAIL;
+
+  if (pthread_mutex_destroy (mutex) == 0
+      && pthread_mutex_init (mutex, attr) == 0)
+    result = PASS;
+
+  return result;
+}
+
+/* Tests setting the mutex type.  */
+static int
+test_settype (pthread_mutex_t *mutex, pthread_mutexattr_t *attr)
+{
+  int result = FAIL;
+
+  if (SET_TYPE (attr, PTHREAD_MUTEX_ERRORCHECK) == 0 /* Set type.  */
+      && mutex_reinit (mutex, attr) == 0
+      && SET_TYPE (attr, PTHREAD_MUTEX_RECURSIVE) == 0
+      && mutex_reinit (mutex, attr) == 0
+      && SET_TYPE (attr, PTHREAD_MUTEX_NORMAL) == 0
+      && mutex_reinit (mutex, attr) == 0)
+    result = PASS;
+
+  return result;
+}
+
+/* Tests setting whether the mutex is robust.  */
+static int
+test_setrobust (pthread_mutex_t *mutex, pthread_mutexattr_t *attr)
+{
+  int result = FAIL;
+
+  if (SET_ROBUST (attr, PTHREAD_MUTEX_ROBUST) == 0 /* Set robust.  */
+      && mutex_reinit (mutex, attr) == 0
+      && SET_ROBUST (attr, PTHREAD_MUTEX_STALLED) == 0
+      && mutex_reinit (mutex, attr) == 0)
+    result = PASS;
+
+  return result;
+}
+
+/* Tests setting whether the mutex can be shared between processes.  */
+static int
+test_setpshared (pthread_mutex_t *mutex, pthread_mutexattr_t *attr)
+{
+  int result = FAIL;
+
+  if (SET_SHARED (attr, PTHREAD_PROCESS_SHARED) == 0 /* Set shared.  */
+      && mutex_reinit (mutex, attr) == 0
+      && SET_SHARED (attr, PTHREAD_PROCESS_PRIVATE) == 0
+      && mutex_reinit (mutex, attr) == 0)
+    result = PASS;
+
+  return result;
+}
+
+/* Tests setting the mutex protocol and, for Priority Protect, the Priority
+   Ceiling.  */
+static int
+test_setprotocol (pthread_mutex_t *mutex, pthread_mutexattr_t *attr)
+{
+  int result = FAIL;
+  int old_prioceiling;
+
+  if (SET_PROTOCOL (attr, PTHREAD_PRIO_INHERIT) == 0 /* Set protocol.  */
+      && mutex_reinit (mutex, attr) == 0
+      && SET_PROTOCOL (attr, PTHREAD_PRIO_PROTECT) == 0
+      && mutex_reinit (mutex, attr) == 0
+      && SET_PRIOCEILING(mutex, PRIOCEILING, &old_prioceiling) == 0
+      && SET_PROTOCOL (attr, PTHREAD_PRIO_NONE) == 0
+      && mutex_reinit (mutex, attr) == 0)
+    result = PASS;
+
+  return result;
+}
diff --git a/nptl/test-mutexattr-printers.py b/nptl/test-mutexattr-printers.py
new file mode 100644
index 0000000000..4464723fbe
--- /dev/null
+++ b/nptl/test-mutexattr-printers.py
@@ -0,0 +1,101 @@
+# Common tests for the MutexPrinter and MutexAttributesPrinter classes.
+#
+# Copyright (C) 2016 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+import sys
+
+from test_printers_common import *
+
+test_source = sys.argv[1]
+test_bin = sys.argv[2]
+printer_files = sys.argv[3:]
+printer_names = ['global glibc-pthread-locks']
+PRIOCEILING = 42
+
+try:
+    init_test(test_bin, printer_files, printer_names)
+    go_to_main()
+
+    check_debug_symbol('struct pthread_mutexattr')
+
+    mutex_var = 'mutex'
+    mutex_to_string = 'pthread_mutex_t'
+
+    attr_var = 'attr'
+    attr_to_string = 'pthread_mutexattr_t'
+
+    break_at(test_source, 'Set type')
+    continue_cmd() # Go to test_settype
+    next_cmd(2)
+    test_printer(attr_var, attr_to_string, {'Type': 'Error check'})
+    test_printer(mutex_var, mutex_to_string, {'Type': 'Error check'})
+    next_cmd(2)
+    test_printer(attr_var, attr_to_string, {'Type': 'Recursive'})
+    test_printer(mutex_var, mutex_to_string, {'Type': 'Recursive'})
+    next_cmd(2)
+    test_printer(attr_var, attr_to_string, {'Type': 'Normal'})
+    test_printer(mutex_var, mutex_to_string, {'Type': 'Normal'})
+
+    break_at(test_source, 'Set robust')
+    continue_cmd() # Go to test_setrobust
+    next_cmd(2)
+    test_printer(attr_var, attr_to_string, {'Robust': 'Yes'})
+    test_printer(mutex_var, mutex_to_string, {'Robust': 'Yes'})
+    next_cmd(2)
+    test_printer(attr_var, attr_to_string, {'Robust': 'No'})
+    test_printer(mutex_var, mutex_to_string, {'Robust': 'No'})
+
+    break_at(test_source, 'Set shared')
+    continue_cmd() # Go to test_setpshared
+    next_cmd(2)
+    test_printer(attr_var, attr_to_string, {'Shared': 'Yes'})
+    test_printer(mutex_var, mutex_to_string, {'Shared': 'Yes'})
+    next_cmd(2)
+    test_printer(attr_var, attr_to_string, {'Shared': 'No'})
+    test_printer(mutex_var, mutex_to_string, {'Shared': 'No'})
+
+    break_at(test_source, 'Set protocol')
+    continue_cmd() # Go to test_setprotocol
+    next_cmd(2)
+    test_printer(attr_var, attr_to_string, {'Protocol': 'Priority inherit'})
+    test_printer(mutex_var, mutex_to_string, {'Protocol': 'Priority inherit'})
+    next_cmd(2)
+    test_printer(attr_var, attr_to_string, {'Protocol': 'Priority protect'})
+    test_printer(mutex_var, mutex_to_string, {'Protocol': 'Priority protect'})
+    next_cmd(2)
+    test_printer(mutex_var, mutex_to_string, {'Priority ceiling':
+                                              str(PRIOCEILING)})
+    next_cmd()
+    test_printer(attr_var, attr_to_string, {'Protocol': 'None'})
+    test_printer(mutex_var, mutex_to_string, {'Protocol': 'None'})
+
+    continue_cmd() # Exit
+
+except (NoLineError, pexpect.TIMEOUT) as exception:
+    print('Error: {0}'.format(exception))
+    result = FAIL
+
+except DebugError as exception:
+    print(exception)
+    result = UNSUPPORTED
+
+else:
+    print('Test succeeded.')
+    result = PASS
+
+exit(result)
diff --git a/nptl/test-rwlock-printers.c b/nptl/test-rwlock-printers.c
new file mode 100644
index 0000000000..dbbe9b80d6
--- /dev/null
+++ b/nptl/test-rwlock-printers.c
@@ -0,0 +1,78 @@
+/* Helper program for testing the pthread_rwlock_t pretty printer.
+
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Keep the calls to the pthread_* functions on separate lines to make it easy
+   to advance through the program using the gdb 'next' command.  */
+
+#include <pthread.h>
+
+#define PASS 0
+#define FAIL 1
+
+static int test_locking_reader (pthread_rwlock_t *rwlock);
+static int test_locking_writer (pthread_rwlock_t *rwlock);
+
+int
+main (void)
+{
+  pthread_rwlock_t rwlock;
+
+  int result = FAIL;
+
+  if (test_locking_reader (&rwlock) == PASS
+      && test_locking_writer (&rwlock) == PASS)
+    result = PASS;
+  /* Else, one of the pthread_rwlock* functions failed.  */
+
+  return result;
+}
+
+/* Tests locking the rwlock multiple times as a reader.  */
+static int
+test_locking_reader (pthread_rwlock_t *rwlock)
+{
+  int result = FAIL;
+
+  if (pthread_rwlock_init (rwlock, NULL) == 0
+      && pthread_rwlock_rdlock (rwlock) == 0 /* Test locking (reader).  */
+      && pthread_rwlock_rdlock (rwlock) == 0
+      && pthread_rwlock_rdlock (rwlock) == 0
+      && pthread_rwlock_unlock (rwlock) == 0
+      && pthread_rwlock_unlock (rwlock) == 0
+      && pthread_rwlock_unlock (rwlock) == 0
+      && pthread_rwlock_destroy (rwlock) == 0)
+    result = PASS;
+
+  return result;
+}
+
+/* Tests locking the rwlock as a writer.  */
+static int
+test_locking_writer (pthread_rwlock_t *rwlock)
+{
+  int result = FAIL;
+
+  if (pthread_rwlock_init (rwlock, NULL) == 0
+      && pthread_rwlock_wrlock (rwlock) == 0 /* Test locking (writer).  */
+      && pthread_rwlock_unlock (rwlock) == 0
+      && pthread_rwlock_destroy (rwlock) == 0)
+    result = PASS;
+
+  return result;
+}
diff --git a/nptl/test-rwlock-printers.py b/nptl/test-rwlock-printers.py
new file mode 100644
index 0000000000..b972fa60d0
--- /dev/null
+++ b/nptl/test-rwlock-printers.py
@@ -0,0 +1,64 @@
+# Common tests for the RWLockPrinter class.
+#
+# Copyright (C) 2016 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+import sys
+
+from test_printers_common import *
+
+test_source = sys.argv[1]
+test_bin = sys.argv[2]
+printer_files = sys.argv[3:]
+printer_names = ['global glibc-pthread-locks']
+
+try:
+    init_test(test_bin, printer_files, printer_names)
+    go_to_main()
+
+    var = 'rwlock'
+    to_string = 'pthread_rwlock_t'
+
+    break_at(test_source, 'Test locking (reader)')
+    continue_cmd() # Go to test_locking_reader
+    test_printer(var, to_string, {'Status': 'Unlocked'})
+    next_cmd()
+    test_printer(var, to_string, {'Status': r'Locked \(Read\)', 'Readers': '1'})
+    next_cmd()
+    test_printer(var, to_string, {'Readers': '2'})
+    next_cmd()
+    test_printer(var, to_string, {'Readers': '3'})
+
+    break_at(test_source, 'Test locking (writer)')
+    continue_cmd() # Go to test_locking_writer
+    test_printer(var, to_string, {'Status': 'Unlocked'})
+    next_cmd()
+    thread_id = get_current_thread_lwpid()
+    test_printer(var, to_string, {'Status': r'Locked \(Write\)',
+                                  'Writer ID': thread_id})
+
+    continue_cmd() # Exit
+
+except (NoLineError, pexpect.TIMEOUT) as exception:
+    print('Error: {0}'.format(exception))
+    result = FAIL
+
+else:
+    print('Test succeeded.')
+    result = PASS
+
+exit(result)
diff --git a/nptl/test-rwlockattr-printers.c b/nptl/test-rwlockattr-printers.c
new file mode 100644
index 0000000000..d12facf41c
--- /dev/null
+++ b/nptl/test-rwlockattr-printers.c
@@ -0,0 +1,98 @@
+/* Helper program for testing the pthread_rwlock_t and pthread_rwlockattr_t
+   pretty printers.
+
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Keep the calls to the pthread_* functions on separate lines to make it easy
+   to advance through the program using the gdb 'next' command.  */
+
+#include <pthread.h>
+
+#define PASS 0
+#define FAIL 1
+
+/* Need these so we don't have lines longer than 79 chars.  */
+#define SET_KIND(attr, kind) pthread_rwlockattr_setkind_np (attr, kind)
+#define SET_SHARED(attr, shared) pthread_rwlockattr_setpshared (attr, shared)
+
+static int rwlock_reinit (pthread_rwlock_t *rwlock,
+			  const pthread_rwlockattr_t *attr);
+static int test_setkind_np (pthread_rwlock_t *rwlock,
+			    pthread_rwlockattr_t *attr);
+static int test_setpshared (pthread_rwlock_t *rwlock,
+			    pthread_rwlockattr_t *attr);
+
+int
+main (void)
+{
+  pthread_rwlock_t rwlock;
+  pthread_rwlockattr_t attr;
+  int result = FAIL;
+
+  if (pthread_rwlockattr_init (&attr) == 0
+      && pthread_rwlock_init (&rwlock, NULL) == 0
+      && test_setkind_np (&rwlock, &attr) == PASS
+      && test_setpshared (&rwlock, &attr) == PASS)
+    result = PASS;
+  /* Else, one of the pthread_rwlock* functions failed.  */
+
+  return result;
+}
+
+/* Destroys RWLOCK and re-initializes it using ATTR.  */
+static int
+rwlock_reinit (pthread_rwlock_t *rwlock, const pthread_rwlockattr_t *attr)
+{
+  int result = FAIL;
+
+  if (pthread_rwlock_destroy (rwlock) == 0
+      && pthread_rwlock_init (rwlock, attr) == 0)
+    result = PASS;
+
+  return result;
+}
+
+/* Tests setting whether the rwlock prefers readers or writers.  */
+static int
+test_setkind_np (pthread_rwlock_t *rwlock, pthread_rwlockattr_t *attr)
+{
+  int result = FAIL;
+
+  if (SET_KIND (attr, PTHREAD_RWLOCK_PREFER_READER_NP) == 0 /* Set kind.  */
+      && rwlock_reinit (rwlock, attr) == PASS
+      && SET_KIND (attr, PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP) == 0
+      && rwlock_reinit (rwlock, attr) == PASS)
+    result = PASS;
+
+  return result;
+}
+
+/* Tests setting whether the rwlock can be shared between processes.  */
+static int
+test_setpshared (pthread_rwlock_t *rwlock, pthread_rwlockattr_t *attr)
+{
+  int result = FAIL;
+
+  if (SET_SHARED (attr, PTHREAD_PROCESS_SHARED) == 0 /* Set shared.  */
+      && rwlock_reinit (rwlock, attr) == PASS
+      && SET_SHARED (attr, PTHREAD_PROCESS_PRIVATE) == 0
+      && rwlock_reinit (rwlock, attr) == PASS)
+    result = PASS;
+
+  return result;
+}
diff --git a/nptl/test-rwlockattr-printers.py b/nptl/test-rwlockattr-printers.py
new file mode 100644
index 0000000000..1ca2dc6c33
--- /dev/null
+++ b/nptl/test-rwlockattr-printers.py
@@ -0,0 +1,73 @@
+# Common tests for the RWLockPrinter and RWLockAttributesPrinter classes.
+#
+# Copyright (C) 2016 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+import sys
+
+from test_printers_common import *
+
+test_source = sys.argv[1]
+test_bin = sys.argv[2]
+printer_files = sys.argv[3:]
+printer_names = ['global glibc-pthread-locks']
+
+try:
+    init_test(test_bin, printer_files, printer_names)
+    go_to_main()
+
+    check_debug_symbol('struct pthread_rwlockattr')
+
+    rwlock_var = 'rwlock'
+    rwlock_to_string = 'pthread_rwlock_t'
+
+    attr_var = 'attr'
+    attr_to_string = 'pthread_rwlockattr_t'
+
+    break_at(test_source, 'Set kind')
+    continue_cmd() # Go to test_setkind_np
+    next_cmd(2)
+    test_printer(rwlock_var, rwlock_to_string, {'Prefers': 'Readers'})
+    test_printer(attr_var, attr_to_string, {'Prefers': 'Readers'})
+    next_cmd(2)
+    test_printer(rwlock_var, rwlock_to_string, {'Prefers': 'Writers'})
+    test_printer(attr_var, attr_to_string, {'Prefers': 'Writers'})
+
+    break_at(test_source, 'Set shared')
+    continue_cmd() # Go to test_setpshared
+    next_cmd(2)
+    test_printer(rwlock_var, rwlock_to_string, {'Shared': 'Yes'})
+    test_printer(attr_var, attr_to_string, {'Shared': 'Yes'})
+    next_cmd(2)
+    test_printer(rwlock_var, rwlock_to_string, {'Shared': 'No'})
+    test_printer(attr_var, attr_to_string, {'Shared': 'No'})
+
+    continue_cmd() # Exit
+
+except (NoLineError, pexpect.TIMEOUT) as exception:
+    print('Error: {0}'.format(exception))
+    result = FAIL
+
+except DebugError as exception:
+    print(exception)
+    result = UNSUPPORTED
+
+else:
+    print('Test succeeded.')
+    result = PASS
+
+exit(result)