exp-drd/drd_mutex.c - fp2-dev/platform/external/valgrind - Gitiles

 /*
   This file is part of drd, a data race detector.

   Copyright (C) 2006-2008 Bart Van Assche
   bart.vanassche@gmail.com

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   This program 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
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307, USA.

   The GNU General Public License is contained in the file COPYING.
 */


 #include "drd_clientobj.h"
 #include "drd_error.h"
 #include "drd_mutex.h"
 #include "priv_drd_clientreq.h"
 #include "pub_tool_errormgr.h"    // VG_(maybe_record_error)()
 #include "pub_tool_libcassert.h"  // tl_assert()
 #include "pub_tool_libcbase.h"    // VG_(strlen)
 #include "pub_tool_libcprint.h"   // VG_(message)()
 #include "pub_tool_machine.h"     // VG_(get_IP)()
 #include "pub_tool_threadstate.h" // VG_(get_running_tid)()


 // Local functions.

 static void mutex_cleanup(struct mutex_info* p);
 static Bool mutex_is_locked(struct mutex_info* const p);


 // Local variables.

 static Bool s_trace_mutex;
 static ULong s_mutex_lock_count;


 // Function definitions.

 void mutex_set_trace(const Bool trace_mutex)
 {
   tl_assert(!! trace_mutex == trace_mutex);
   s_trace_mutex = trace_mutex;
 }

 static
 void mutex_initialize(struct mutex_info* const p,
                       const Addr mutex, const MutexT mutex_type)
 {
   tl_assert(mutex != 0);

   tl_assert(p->a1 == mutex);
   p->cleanup             = (void(*)(DrdClientobj*))&mutex_cleanup;
   p->mutex_type          = mutex_type;
   p->recursion_count     = 0;
   p->owner               = DRD_INVALID_THREADID;
   p->last_locked_segment = 0;
 }

 /** Deallocate the memory that was allocated by mutex_initialize(). */
 static void mutex_cleanup(struct mutex_info* p)
 {
   tl_assert(p);

   if (s_trace_mutex)
   {
     VG_(message)(Vg_UserMsg,
                  "[%d/%d] mutex_destroy   %s 0x%lx",
                  VG_(get_running_tid)(),
                  thread_get_running_tid(),
                  mutex_get_typename(p),
                  p->a1);
   }

   if (mutex_is_locked(p))
   {
     MutexErrInfo MEI = { p->a1, p->recursion_count, p->owner };
     VG_(maybe_record_error)(VG_(get_running_tid)(),
                             MutexErr,
                             VG_(get_IP)(VG_(get_running_tid)()),
                             "Destroying locked mutex",
                             &MEI);
   }

   sg_put(p->last_locked_segment);
   p->last_locked_segment = 0;
 }

 static void not_a_mutex(const Addr mutex)
 {
   MutexErrInfo MEI = { mutex, -1, DRD_INVALID_THREADID };
   VG_(maybe_record_error)(VG_(get_running_tid)(),
                           MutexErr,
                           VG_(get_IP)(VG_(get_running_tid)()),
                           "Not a mutex",
                           &MEI);
 }

 static
 struct mutex_info*
 mutex_get_or_allocate(const Addr mutex, const MutexT mutex_type)
 {
   struct mutex_info* p;

   tl_assert(offsetof(DrdClientobj, mutex) == 0);
   p = &clientobj_get(mutex, ClientMutex)->mutex;
   if (p)
   {
     return p;
   }

   if (clientobj_present(mutex, mutex + 1))
   {
     not_a_mutex(mutex);
     return 0;
   }

   p = &clientobj_add(mutex, ClientMutex)->mutex;
   mutex_initialize(p, mutex, mutex_type);
   return p;
 }

 struct mutex_info* mutex_get(const Addr mutex)
 {
   tl_assert(offsetof(DrdClientobj, mutex) == 0);
   return &clientobj_get(mutex, ClientMutex)->mutex;
 }

 /** Called before pthread_mutex_init(). */
 struct mutex_info*
 mutex_init(const Addr mutex, const MutexT mutex_type)
 {
   struct mutex_info* p;

   if (s_trace_mutex)
   {
     VG_(message)(Vg_UserMsg,
                  "[%d/%d] mutex_init      %s 0x%lx",
                  VG_(get_running_tid)(),
                  thread_get_running_tid(),
                  mutex_type_name(mutex_type),
                  mutex);
   }

   if (mutex_type == mutex_type_invalid_mutex)
   {
     not_a_mutex(mutex);
     return 0;
   }

   p = mutex_get(mutex);
   if (p)
   {
     const ThreadId vg_tid = VG_(get_running_tid)();
     MutexErrInfo MEI
       = { p->a1, p->recursion_count, p->owner };
     VG_(maybe_record_error)(vg_tid,
                             MutexErr,
                             VG_(get_IP)(vg_tid),
                             "Mutex reinitialization",
                             &MEI);
     return p;
   }
   p = mutex_get_or_allocate(mutex, mutex_type);

   return p;
 }

 /** Called after pthread_mutex_destroy(). */
 void mutex_post_destroy(const Addr mutex)
 {
   struct mutex_info* p;

   p = mutex_get(mutex);
   if (p == 0)
   {
     not_a_mutex(mutex);
     return;
   }

   clientobj_remove(mutex, ClientMutex);
 }

 /** Called before pthread_mutex_lock() is invoked. If a data structure for
  *  the client-side object was not yet created, do this now. Also check whether
  *  an attempt is made to lock recursively a synchronization object that must
  *  not be locked recursively.
  */
 void mutex_pre_lock(const Addr mutex, const MutexT mutex_type,
                     const Bool trylock)
 {
   struct mutex_info* p;

   p = mutex_get_or_allocate(mutex, mutex_type);
   if (s_trace_mutex)
   {
     VG_(message)(Vg_UserMsg,
                  "[%d/%d] pre_mutex_lock  %s 0x%lx rc %d owner %d",
                  VG_(get_running_tid)(),
                  thread_get_running_tid(),
                  p ? mutex_get_typename(p) : "(?)",
                  mutex,
                  p ? p->recursion_count : -1,
                  p ? p->owner : DRD_INVALID_THREADID);
   }

   if (p == 0)
   {
     not_a_mutex(mutex);
     return;
   }

   tl_assert(p);

   if (mutex_type == mutex_type_invalid_mutex)
   {
     not_a_mutex(mutex);
     return;
   }

   if (! trylock
       && p->owner == thread_get_running_tid()
       && p->recursion_count >= 1
       && mutex_type != mutex_type_recursive_mutex)
   {
     MutexErrInfo MEI = { p->a1, p->recursion_count, p->owner };
     VG_(maybe_record_error)(VG_(get_running_tid)(),
                             MutexErr,
                             VG_(get_IP)(VG_(get_running_tid)()),
                             "Recursive locking not allowed",
                             &MEI);
   }
 }

 /**
  * Update mutex_info state when locking the pthread_mutex_t mutex.
  * Note: this function must be called after pthread_mutex_lock() has been
  * called, or a race condition is triggered !
  */
 void mutex_post_lock(const Addr mutex, const Bool took_lock)
 {
   const DrdThreadId drd_tid = thread_get_running_tid();
   struct mutex_info* p;

   p = mutex_get(mutex);

   if (s_trace_mutex)
   {
     VG_(message)(Vg_UserMsg,
                  "[%d/%d] post_mutex_lock %s 0x%lx rc %d owner %d%s",
                  VG_(get_running_tid)(),
                  drd_tid,
                  p ? mutex_get_typename(p) : "(?)",
                  mutex,
                  p ? p->recursion_count : 0,
                  p ? p->owner : VG_INVALID_THREADID,
                  took_lock ? "" : " (locking failed)");
   }

   if (! p || ! took_lock)
     return;

   if (p->recursion_count == 0)
   {
     const DrdThreadId last_owner = p->owner;

     if (last_owner != drd_tid && last_owner != DRD_INVALID_THREADID)
     {
       tl_assert(p->last_locked_segment);
       thread_combine_vc2(drd_tid, &p->last_locked_segment->vc);
     }
     thread_new_segment(drd_tid);

     p->owner = drd_tid;
     s_mutex_lock_count++;
   }
   else if (p->owner != drd_tid)
   {
     VG_(message)(Vg_UserMsg,
                  "The impossible happened: mutex 0x%lx is locked"
                  " simultaneously by two threads (recursion count %d,"
                  " owners %d and %d) !",
                  p->a1, p->recursion_count, p->owner, drd_tid);
     p->owner = drd_tid;
   }
   p->recursion_count++;
 }

 /**
  * Update mutex_info state when unlocking the pthread_mutex_t mutex.
  * Note: this function must be called before pthread_mutex_unlock() is called,
  * or a race condition is triggered !
  * @return New value of the mutex recursion count.
  * @param mutex Pointer to pthread_mutex_t data structure in the client space.
  * @param tid ThreadId of the thread calling pthread_mutex_unlock().
  * @param vc Pointer to the current vector clock of thread tid.
  */
 void mutex_unlock(const Addr mutex, const MutexT mutex_type)
 {
   const DrdThreadId drd_tid = thread_get_running_tid();
   const ThreadId vg_tid = VG_(get_running_tid)();
   struct mutex_info* const p = mutex_get(mutex);

   if (s_trace_mutex)
   {
     VG_(message)(Vg_UserMsg,
                  "[%d/%d] mutex_unlock    %s 0x%lx rc %d",
                  vg_tid,
                  drd_tid,
                  p ? mutex_get_typename(p) : "(?)",
                  mutex,
                  p ? p->recursion_count : 0);
   }

   if (p == 0 || mutex_type == mutex_type_invalid_mutex)
   {
     not_a_mutex(mutex);
     return;
   }

   if (p->owner == DRD_INVALID_THREADID)
   {
     MutexErrInfo MEI = { p->a1, p->recursion_count, p->owner };
     VG_(maybe_record_error)(vg_tid,
                             MutexErr,
                             VG_(get_IP)(vg_tid),
                             "Mutex not locked",
                             &MEI);
     return;
   }

   tl_assert(p);
   if (p->mutex_type != mutex_type)
   {
     VG_(message)(Vg_UserMsg, "??? mutex 0x%lx: type changed from %d into %d",
                  p->a1, p->mutex_type, mutex_type);
   }
   tl_assert(p->mutex_type == mutex_type);
   tl_assert(p->owner != DRD_INVALID_THREADID);

   if (p->owner != drd_tid || p->recursion_count <= 0)
   {
     MutexErrInfo MEI = { p->a1, p->recursion_count, p->owner };
     VG_(maybe_record_error)(vg_tid,
                             MutexErr,
                             VG_(get_IP)(vg_tid),
                             "Mutex not locked by calling thread",
                             &MEI);
     return;
   }
   tl_assert(p->recursion_count > 0);
   p->recursion_count--;
   tl_assert(p->recursion_count >= 0);

   if (p->recursion_count == 0)
   {
     /* This pthread_mutex_unlock() call really unlocks the mutex. Save the */
     /* current vector clock of the thread such that it is available when  */
     /* this mutex is locked again.                                        */

     thread_get_latest_segment(&p->last_locked_segment, drd_tid);
     thread_new_segment(drd_tid);
   }
 }

 const char* mutex_get_typename(struct mutex_info* const p)
 {
   tl_assert(p);

   return mutex_type_name(p->mutex_type);
 }

 const char* mutex_type_name(const MutexT mt)
 {
   switch (mt)
   {
   case mutex_type_invalid_mutex:
     return "invalid mutex";
   case mutex_type_recursive_mutex:
     return "recursive mutex";
   case mutex_type_errorcheck_mutex:
     return "error checking mutex";
   case mutex_type_default_mutex:
     return "mutex";
   case mutex_type_spinlock:
     return "spinlock";
   default:
     tl_assert(0);
   }
   return "?";
 }

 /** Return true if the specified mutex is locked by any thread. */
 static Bool mutex_is_locked(struct mutex_info* const p)
 {
   tl_assert(p);
   return (p->recursion_count > 0);
 }

 Bool mutex_is_locked_by(const Addr mutex, const DrdThreadId tid)
 {
   struct mutex_info* const p = mutex_get(mutex);
   if (p)
   {
     return (p->recursion_count > 0 && p->owner == tid);
   }
   return False;
 }

 int mutex_get_recursion_count(const Addr mutex)
 {
   struct mutex_info* const p = mutex_get(mutex);
   tl_assert(p);
   return p->recursion_count;
 }

 /**
  * Call this function when thread tid stops to exist, such that the
  * "last owner" field can be cleared if it still refers to that thread.
  */
 void mutex_thread_delete(const DrdThreadId tid)
 {
   struct mutex_info* p;

   clientobj_resetiter();
   for ( ; (p = &clientobj_next(ClientMutex)->mutex) != 0; )
   {
     if (p->owner == tid && p->recursion_count > 0)
     {
       MutexErrInfo MEI
         = { p->a1, p->recursion_count, p->owner };
       VG_(maybe_record_error)(VG_(get_running_tid)(),
                               MutexErr,
                               VG_(get_IP)(VG_(get_running_tid)()),
                               "Mutex still locked at thread exit",
                               &MEI);
       p->owner = VG_INVALID_THREADID;
     }
   }
 }

 ULong get_mutex_lock_count(void)
 {
   return s_mutex_lock_count;
 }
	/*
	This file is part of drd, a data race detector.

	Copyright (C) 2006-2008 Bart Van Assche
	bart.vanassche@gmail.com

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License as
	published by the Free Software Foundation; either version 2 of the
	License, or (at your option) any later version.

	This program 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
	General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
	02111-1307, USA.

	The GNU General Public License is contained in the file COPYING.
	*/


	#include "drd_clientobj.h"
	#include "drd_error.h"
	#include "drd_mutex.h"
	#include "priv_drd_clientreq.h"
	#include "pub_tool_errormgr.h" // VG_(maybe_record_error)()
	#include "pub_tool_libcassert.h" // tl_assert()
	#include "pub_tool_libcbase.h" // VG_(strlen)
	#include "pub_tool_libcprint.h" // VG_(message)()
	#include "pub_tool_machine.h" // VG_(get_IP)()
	#include "pub_tool_threadstate.h" // VG_(get_running_tid)()


	// Local functions.

	static void mutex_cleanup(struct mutex_info* p);
	static Bool mutex_is_locked(struct mutex_info* const p);


	// Local variables.

	static Bool s_trace_mutex;
	static ULong s_mutex_lock_count;


	// Function definitions.

	void mutex_set_trace(const Bool trace_mutex)
	{
	tl_assert(!! trace_mutex == trace_mutex);
	s_trace_mutex = trace_mutex;
	}

	static
	void mutex_initialize(struct mutex_info* const p,
	const Addr mutex, const MutexT mutex_type)
	{
	tl_assert(mutex != 0);

	tl_assert(p->a1 == mutex);
	p->cleanup = (void()(DrdClientobj))&mutex_cleanup;
	p->mutex_type = mutex_type;
	p->recursion_count = 0;
	p->owner = DRD_INVALID_THREADID;
	p->last_locked_segment = 0;
	}

	/** Deallocate the memory that was allocated by mutex_initialize(). */
	static void mutex_cleanup(struct mutex_info* p)
	{
	tl_assert(p);

	if (s_trace_mutex)
	{
	VG_(message)(Vg_UserMsg,
	"[%d/%d] mutex_destroy %s 0x%lx",
	VG_(get_running_tid)(),
	thread_get_running_tid(),
	mutex_get_typename(p),
	p->a1);
	}

	if (mutex_is_locked(p))
	{
	MutexErrInfo MEI = { p->a1, p->recursion_count, p->owner };
	VG_(maybe_record_error)(VG_(get_running_tid)(),
	MutexErr,
	VG_(get_IP)(VG_(get_running_tid)()),
	"Destroying locked mutex",
	&MEI);
	}

	sg_put(p->last_locked_segment);
	p->last_locked_segment = 0;
	}

	static void not_a_mutex(const Addr mutex)
	{
	MutexErrInfo MEI = { mutex, -1, DRD_INVALID_THREADID };
	VG_(maybe_record_error)(VG_(get_running_tid)(),
	MutexErr,
	VG_(get_IP)(VG_(get_running_tid)()),
	"Not a mutex",
	&MEI);
	}

	static
	struct mutex_info*
	mutex_get_or_allocate(const Addr mutex, const MutexT mutex_type)
	{
	struct mutex_info* p;

	tl_assert(offsetof(DrdClientobj, mutex) == 0);
	p = &clientobj_get(mutex, ClientMutex)->mutex;
	if (p)
	{
	return p;
	}

	if (clientobj_present(mutex, mutex + 1))
	{
	not_a_mutex(mutex);
	return 0;
	}

	p = &clientobj_add(mutex, ClientMutex)->mutex;
	mutex_initialize(p, mutex, mutex_type);
	return p;
	}

	struct mutex_info* mutex_get(const Addr mutex)
	{
	tl_assert(offsetof(DrdClientobj, mutex) == 0);
	return &clientobj_get(mutex, ClientMutex)->mutex;
	}

	/** Called before pthread_mutex_init(). */
	struct mutex_info*
	mutex_init(const Addr mutex, const MutexT mutex_type)
	{
	struct mutex_info* p;

	if (s_trace_mutex)
	{
	VG_(message)(Vg_UserMsg,
	"[%d/%d] mutex_init %s 0x%lx",
	VG_(get_running_tid)(),
	thread_get_running_tid(),
	mutex_type_name(mutex_type),
	mutex);
	}

	if (mutex_type == mutex_type_invalid_mutex)
	{
	not_a_mutex(mutex);
	return 0;
	}

	p = mutex_get(mutex);
	if (p)
	{
	const ThreadId vg_tid = VG_(get_running_tid)();
	MutexErrInfo MEI
	= { p->a1, p->recursion_count, p->owner };
	VG_(maybe_record_error)(vg_tid,
	MutexErr,
	VG_(get_IP)(vg_tid),
	"Mutex reinitialization",
	&MEI);
	return p;
	}
	p = mutex_get_or_allocate(mutex, mutex_type);

	return p;
	}

	/** Called after pthread_mutex_destroy(). */
	void mutex_post_destroy(const Addr mutex)
	{
	struct mutex_info* p;

	p = mutex_get(mutex);
	if (p == 0)
	{
	not_a_mutex(mutex);
	return;
	}

	clientobj_remove(mutex, ClientMutex);
	}

	/** Called before pthread_mutex_lock() is invoked. If a data structure for
	* the client-side object was not yet created, do this now. Also check whether
	* an attempt is made to lock recursively a synchronization object that must
	* not be locked recursively.
	*/
	void mutex_pre_lock(const Addr mutex, const MutexT mutex_type,
	const Bool trylock)
	{
	struct mutex_info* p;

	p = mutex_get_or_allocate(mutex, mutex_type);
	if (s_trace_mutex)
	{
	VG_(message)(Vg_UserMsg,
	"[%d/%d] pre_mutex_lock %s 0x%lx rc %d owner %d",
	VG_(get_running_tid)(),
	thread_get_running_tid(),
	p ? mutex_get_typename(p) : "(?)",
	mutex,
	p ? p->recursion_count : -1,
	p ? p->owner : DRD_INVALID_THREADID);
	}

	if (p == 0)
	{
	not_a_mutex(mutex);
	return;
	}

	tl_assert(p);

	if (mutex_type == mutex_type_invalid_mutex)
	{
	not_a_mutex(mutex);
	return;
	}

	if (! trylock
	&& p->owner == thread_get_running_tid()
	&& p->recursion_count >= 1
	&& mutex_type != mutex_type_recursive_mutex)
	{
	MutexErrInfo MEI = { p->a1, p->recursion_count, p->owner };
	VG_(maybe_record_error)(VG_(get_running_tid)(),
	MutexErr,
	VG_(get_IP)(VG_(get_running_tid)()),
	"Recursive locking not allowed",
	&MEI);
	}
	}

	/**
	* Update mutex_info state when locking the pthread_mutex_t mutex.
	* Note: this function must be called after pthread_mutex_lock() has been
	* called, or a race condition is triggered !
	*/
	void mutex_post_lock(const Addr mutex, const Bool took_lock)
	{
	const DrdThreadId drd_tid = thread_get_running_tid();
	struct mutex_info* p;

	p = mutex_get(mutex);

	if (s_trace_mutex)
	{
	VG_(message)(Vg_UserMsg,
	"[%d/%d] post_mutex_lock %s 0x%lx rc %d owner %d%s",
	VG_(get_running_tid)(),
	drd_tid,
	p ? mutex_get_typename(p) : "(?)",
	mutex,
	p ? p->recursion_count : 0,
	p ? p->owner : VG_INVALID_THREADID,
	took_lock ? "" : " (locking failed)");
	}

	if (! p \|\| ! took_lock)
	return;

	if (p->recursion_count == 0)
	{
	const DrdThreadId last_owner = p->owner;

	if (last_owner != drd_tid && last_owner != DRD_INVALID_THREADID)
	{
	tl_assert(p->last_locked_segment);
	thread_combine_vc2(drd_tid, &p->last_locked_segment->vc);
	}
	thread_new_segment(drd_tid);

	p->owner = drd_tid;
	s_mutex_lock_count++;
	}
	else if (p->owner != drd_tid)
	{
	VG_(message)(Vg_UserMsg,
	"The impossible happened: mutex 0x%lx is locked"
	" simultaneously by two threads (recursion count %d,"
	" owners %d and %d) !",
	p->a1, p->recursion_count, p->owner, drd_tid);
	p->owner = drd_tid;
	}
	p->recursion_count++;
	}

	/**
	* Update mutex_info state when unlocking the pthread_mutex_t mutex.
	* Note: this function must be called before pthread_mutex_unlock() is called,
	* or a race condition is triggered !
	* @return New value of the mutex recursion count.
	* @param mutex Pointer to pthread_mutex_t data structure in the client space.
	* @param tid ThreadId of the thread calling pthread_mutex_unlock().
	* @param vc Pointer to the current vector clock of thread tid.
	*/
	void mutex_unlock(const Addr mutex, const MutexT mutex_type)
	{
	const DrdThreadId drd_tid = thread_get_running_tid();
	const ThreadId vg_tid = VG_(get_running_tid)();
	struct mutex_info* const p = mutex_get(mutex);

	if (s_trace_mutex)
	{
	VG_(message)(Vg_UserMsg,
	"[%d/%d] mutex_unlock %s 0x%lx rc %d",
	vg_tid,
	drd_tid,
	p ? mutex_get_typename(p) : "(?)",
	mutex,
	p ? p->recursion_count : 0);
	}

	if (p == 0 \|\| mutex_type == mutex_type_invalid_mutex)
	{
	not_a_mutex(mutex);
	return;
	}

	if (p->owner == DRD_INVALID_THREADID)
	{
	MutexErrInfo MEI = { p->a1, p->recursion_count, p->owner };
	VG_(maybe_record_error)(vg_tid,
	MutexErr,
	VG_(get_IP)(vg_tid),
	"Mutex not locked",
	&MEI);
	return;
	}

	tl_assert(p);
	if (p->mutex_type != mutex_type)
	{
	VG_(message)(Vg_UserMsg, "??? mutex 0x%lx: type changed from %d into %d",
	p->a1, p->mutex_type, mutex_type);
	}
	tl_assert(p->mutex_type == mutex_type);
	tl_assert(p->owner != DRD_INVALID_THREADID);

	if (p->owner != drd_tid \|\| p->recursion_count <= 0)
	{
	MutexErrInfo MEI = { p->a1, p->recursion_count, p->owner };
	VG_(maybe_record_error)(vg_tid,
	MutexErr,
	VG_(get_IP)(vg_tid),
	"Mutex not locked by calling thread",
	&MEI);
	return;
	}
	tl_assert(p->recursion_count > 0);
	p->recursion_count--;
	tl_assert(p->recursion_count >= 0);

	if (p->recursion_count == 0)
	{
	/* This pthread_mutex_unlock() call really unlocks the mutex. Save the */
	/* current vector clock of the thread such that it is available when */
	/* this mutex is locked again. */

	thread_get_latest_segment(&p->last_locked_segment, drd_tid);
	thread_new_segment(drd_tid);
	}
	}

	const char* mutex_get_typename(struct mutex_info* const p)
	{
	tl_assert(p);

	return mutex_type_name(p->mutex_type);
	}

	const char* mutex_type_name(const MutexT mt)
	{
	switch (mt)
	{
	case mutex_type_invalid_mutex:
	return "invalid mutex";
	case mutex_type_recursive_mutex:
	return "recursive mutex";
	case mutex_type_errorcheck_mutex:
	return "error checking mutex";
	case mutex_type_default_mutex:
	return "mutex";
	case mutex_type_spinlock:
	return "spinlock";
	default:
	tl_assert(0);
	}
	return "?";
	}

	/** Return true if the specified mutex is locked by any thread. */
	static Bool mutex_is_locked(struct mutex_info* const p)
	{
	tl_assert(p);
	return (p->recursion_count > 0);
	}

	Bool mutex_is_locked_by(const Addr mutex, const DrdThreadId tid)
	{
	struct mutex_info* const p = mutex_get(mutex);
	if (p)
	{
	return (p->recursion_count > 0 && p->owner == tid);
	}
	return False;
	}

	int mutex_get_recursion_count(const Addr mutex)
	{
	struct mutex_info* const p = mutex_get(mutex);
	tl_assert(p);
	return p->recursion_count;
	}

	/**
	* Call this function when thread tid stops to exist, such that the
	* "last owner" field can be cleared if it still refers to that thread.
	*/
	void mutex_thread_delete(const DrdThreadId tid)
	{
	struct mutex_info* p;

	clientobj_resetiter();
	for ( ; (p = &clientobj_next(ClientMutex)->mutex) != 0; )
	{
	if (p->owner == tid && p->recursion_count > 0)
	{
	MutexErrInfo MEI
	= { p->a1, p->recursion_count, p->owner };
	VG_(maybe_record_error)(VG_(get_running_tid)(),
	MutexErr,
	VG_(get_IP)(VG_(get_running_tid)()),
	"Mutex still locked at thread exit",
	&MEI);
	p->owner = VG_INVALID_THREADID;
	}
	}
	}

	ULong get_mutex_lock_count(void)
	{
	return s_mutex_lock_count;
	}