Windows improvements : manual backport of

htttp://lists.mysql.com/commits/50957?f=plain
      
Always use TLS functions instead of __declspec(thread) to access 
thread local storage variables.
The change removes the necessity to recomplile the same source
files twice -  with USE_TLS for DLLs and without USE_TLS for EXEs.
Real benefit of this change is better readability and maintainability
of TLS functions within MySQL.
              
There is a performance loss using TlsXXX functions compared to __declspec 
but the difference is negligible in practice. In a sysbench-like benchmark 
I ran with with TlsGetValue, pthread_[get|set]_specific was called 600000000 
times and took 0.17sec of total 35min CPU time, or 0.008%.

client/CMakeLists.txt

@@ -14,7 +14,7 @@
 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 INCLUDE("${PROJECT_SOURCE_DIR}/win/mysql_manifest.cmake")
 
-# We use the "mysqlclient_notls" library here just as safety, in case
+# We use the "mysqlclient" library here just as safety, in case
 # any of the clients here would go beyond the client API and access the
 # Thread Local Storage directly.
 
@@ -30,27 +30,27 @@ INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/include
                     ${CMAKE_SOURCE_DIR}/strings)
 
 ADD_EXECUTABLE(mysql completion_hash.cc mysql.cc readline.cc sql_string.cc ../mysys/my_conio.c)
-TARGET_LINK_LIBRARIES(mysql mysqlclient_notls wsock32)
+TARGET_LINK_LIBRARIES(mysql mysqlclient wsock32)
 
 ADD_EXECUTABLE(mysqltest mysqltest.cc)
 SET_SOURCE_FILES_PROPERTIES(mysqltest.cc PROPERTIES COMPILE_FLAGS "-DTHREADS")
 TARGET_LINK_LIBRARIES(mysqltest mysqlclient mysys regex wsock32 dbug)
 
 ADD_EXECUTABLE(mysqlcheck mysqlcheck.c)
-TARGET_LINK_LIBRARIES(mysqlcheck mysqlclient_notls wsock32)
+TARGET_LINK_LIBRARIES(mysqlcheck mysqlclient wsock32)
 
 ADD_EXECUTABLE(mysqldump mysqldump.c ../sql-common/my_user.c ../mysys/mf_getdate.c)
-TARGET_LINK_LIBRARIES(mysqldump mysqlclient_notls wsock32)
+TARGET_LINK_LIBRARIES(mysqldump mysqlclient wsock32)
 
 ADD_EXECUTABLE(mysqlimport mysqlimport.c)
-TARGET_LINK_LIBRARIES(mysqlimport mysqlclient_notls wsock32)
+TARGET_LINK_LIBRARIES(mysqlimport mysqlclient wsock32)
 
 ADD_EXECUTABLE(mysql_upgrade mysql_upgrade.c ../mysys/my_getpagesize.c)
-TARGET_LINK_LIBRARIES(mysql_upgrade mysqlclient_notls wsock32)
+TARGET_LINK_LIBRARIES(mysql_upgrade mysqlclient wsock32)
 ADD_DEPENDENCIES(mysql_upgrade GenFixPrivs)
 
 ADD_EXECUTABLE(mysqlshow mysqlshow.c)
-TARGET_LINK_LIBRARIES(mysqlshow mysqlclient_notls wsock32)
+TARGET_LINK_LIBRARIES(mysqlshow mysqlclient wsock32)
 
 ADD_EXECUTABLE(mysqlbinlog mysqlbinlog.cc
 			   ../mysys/mf_tempdir.c
@@ -59,10 +59,10 @@ ADD_EXECUTABLE(mysqlbinlog mysqlbinlog.cc
 			   ../mysys/my_bitmap.c
 			   ../mysys/my_vle.c
 			   ../mysys/base64.c)
-TARGET_LINK_LIBRARIES(mysqlbinlog mysqlclient_notls wsock32)
+TARGET_LINK_LIBRARIES(mysqlbinlog mysqlclient wsock32)
 
 ADD_EXECUTABLE(mysqladmin mysqladmin.cc)
-TARGET_LINK_LIBRARIES(mysqladmin mysqlclient_notls wsock32)
+TARGET_LINK_LIBRARIES(mysqladmin mysqlclient wsock32)
 
 ADD_EXECUTABLE(mysqlslap mysqlslap.c)
 SET_SOURCE_FILES_PROPERTIES(mysqlslap.c PROPERTIES COMPILE_FLAGS "-DTHREADS")

include/my_pthread.h

@@ -100,7 +100,6 @@ struct timespec {
 }
 
 void win_pthread_init(void);
-int win_pthread_setspecific(void *A,void *B,uint length);
 int win_pthread_mutex_trylock(pthread_mutex_t *mutex);
 int pthread_create(pthread_t *,pthread_attr_t *,pthread_handler,void *);
 int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr);
@@ -126,33 +125,16 @@ void pthread_exit(void *a);	 /* was #define pthread_exit(A) ExitThread(A)*/
 #define _REENTRANT			1
 #define HAVE_PTHREAD_ATTR_SETSTACKSIZE	1
 
-/*
-  Windows has two ways to use thread local storage. The most efficient
-  is using __declspec(thread), but that does not work properly when
-  used in a .dll that is loaded at runtime, after program load. So for
-  libmysql.dll and libmysqld.dll we define USE_TLS in order to use the
-  TlsXxx() API instead, which works in all cases.
-*/
-#ifdef USE_TLS					/* For LIBMYSQL.DLL */
+
 #undef SAFE_MUTEX				/* This will cause conflicts */
 #define pthread_key(T,V)  DWORD V
 #define pthread_key_create(A,B) ((*A=TlsAlloc())==0xFFFFFFFF)
 #define pthread_key_delete(A) TlsFree(A)
+#define my_pthread_setspecific_ptr(T,V) (!TlsSetValue((T),(V)))
+#define pthread_setspecific(A,B) (!TlsSetValue((A),(B)))
 #define pthread_getspecific(A) (TlsGetValue(A))
 #define my_pthread_getspecific(T,A) ((T) TlsGetValue(A))
 #define my_pthread_getspecific_ptr(T,V) ((T) TlsGetValue(V))
-#define my_pthread_setspecific_ptr(T,V) (!TlsSetValue((T),(V)))
-#define pthread_setspecific(A,B) (!TlsSetValue((A),(B)))
-#else
-#define pthread_key(T,V) __declspec(thread) T V
-#define pthread_key_create(A,B) pthread_dummy(0)
-#define pthread_key_delete(A) pthread_dummy(0)
-#define pthread_getspecific(A) (&(A))
-#define my_pthread_getspecific(T,A) (&(A))
-#define my_pthread_getspecific_ptr(T,V) (V)
-#define my_pthread_setspecific_ptr(T,V) ((T)=(V),0)
-#define pthread_setspecific(A,B) win_pthread_setspecific(&(A),(B),sizeof(A))
-#endif /* USE_TLS */
 
 #define pthread_equal(A,B) ((A) == (B))
 #define pthread_mutex_init(A,B)  (InitializeCriticalSection(A),0)

libmysql/CMakeLists.txt

@@ -100,29 +100,13 @@ SET(CLIENT_SOURCES   ../mysys/array.c ../strings/bchange.c ../strings/bmove.c
                      ../vio/viossl.c ../vio/viosslfactories.c ../strings/xml.c ../mysys/mf_qsort.c
 		     ../mysys/my_getsystime.c ../mysys/my_sync.c ../mysys/my_winerr.c ../mysys/my_winfile.c ${LIB_SOURCES})
 
-# Need to set USE_TLS for building the DLL, since __declspec(thread)
-# approach to thread local storage does not work properly in DLLs.
-#
-# The static library might be used to form another DLL, as is the case
-# with the ODBC driver, so it has to be compiled with USE_TLS as well.
-#
-# We create a third library without USE_TLS for internal use. We can't
-# be sure that some client application part of this build doesn't go
-# beond the documented API, and try access the Thread Local Storage.
-# The "_notls" means no Tls*() functions used, i.e. "static" TLS.
+
 
 ADD_LIBRARY(mysqlclient       STATIC ${CLIENT_SOURCES})
 ADD_DEPENDENCIES(mysqlclient GenError)
 TARGET_LINK_LIBRARIES(mysqlclient)
 
-ADD_LIBRARY(mysqlclient_notls STATIC ${CLIENT_SOURCES})
-ADD_DEPENDENCIES(mysqlclient_notls GenError)
-TARGET_LINK_LIBRARIES(mysqlclient_notls)
-
 ADD_LIBRARY(libmysql          SHARED ${CLIENT_SOURCES} dll.c libmysql.def)
-IF(WIN32)
-  SET_TARGET_PROPERTIES(libmysql mysqlclient PROPERTIES COMPILE_FLAGS "-DUSE_TLS")
-ENDIF(WIN32)
 ADD_DEPENDENCIES(libmysql GenError)
 TARGET_LINK_LIBRARIES(libmysql wsock32)
 

libmysqld/CMakeLists.txt

@@ -16,12 +16,6 @@
 SET(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -DSAFEMALLOC -DSAFE_MUTEX")
 SET(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -DSAFEMALLOC -DSAFE_MUTEX")
 
-# Need to set USE_TLS, since __declspec(thread) approach to thread local
-# storage does not work properly in DLLs.
-IF(WIN32)
-  ADD_DEFINITIONS(-DUSE_TLS)
-ENDIF(WIN32)
-
 ADD_DEFINITIONS(-DMYSQL_SERVER -DEMBEDDED_LIBRARY -DHAVE_DLOPEN)
 
 INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/include 

libmysqld/examples/CMakeLists.txt

@@ -20,9 +20,6 @@ INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/include
                     ${CMAKE_SOURCE_DIR}/extra/yassl/include)
 
 # Currently does not work with DBUG, there are missing symbols reported.
-IF(WIN32)
-  ADD_DEFINITIONS(-DUSE_TLS)
-ENDIF(WIN32)
 
 ADD_DEFINITIONS(-DEMBEDDED_LIBRARY)
 

mysys/my_thr_init.c

@@ -23,11 +23,7 @@
 #include <signal.h>
 
 #ifdef THREAD
-#ifdef USE_TLS
 pthread_key(struct st_my_thread_var*, THR_KEY_mysys);
-#else
-pthread_key(struct st_my_thread_var, THR_KEY_mysys);
-#endif /* USE_TLS */
 pthread_mutex_t THR_LOCK_malloc,THR_LOCK_open,
 	        THR_LOCK_lock,THR_LOCK_isam,THR_LOCK_myisam,THR_LOCK_heap,
                 THR_LOCK_net, THR_LOCK_charset, THR_LOCK_threads, THR_LOCK_time;
@@ -258,7 +254,6 @@ my_bool my_thread_init(void)
           (ulong) pthread_self());
 #endif  
 
-#if !defined(__WIN__) || defined(USE_TLS)
   if (my_pthread_getspecific(struct st_my_thread_var *,THR_KEY_mysys))
   {
 #ifdef EXTRA_DEBUG_THREADS
@@ -273,15 +268,6 @@ my_bool my_thread_init(void)
     goto end;
   }
   pthread_setspecific(THR_KEY_mysys,tmp);
-
-#else /* defined(__WIN__) && !(defined(USE_TLS) */
-  /*
-    Skip initialization if the thread specific variable is already initialized
-  */
-  if (THR_KEY_mysys.id)
-    goto end;
-  tmp= &THR_KEY_mysys;
-#endif
 #if defined(__WIN__) && defined(EMBEDDED_LIBRARY)
   tmp->pthread_self= (pthread_t) getpid();
 #else
@@ -342,11 +328,7 @@ void my_thread_end(void)
     pthread_cond_destroy(&tmp->suspend);
 #endif
     pthread_mutex_destroy(&tmp->mutex);
-#if !defined(__WIN__) || defined(USE_TLS)
     free(tmp);
-#else
-    tmp->init= 0;
-#endif
 
     /*
       Decrement counter for number of running threads. We are using this
@@ -360,10 +342,7 @@ void my_thread_end(void)
       pthread_cond_signal(&THR_COND_threads);
    pthread_mutex_unlock(&THR_LOCK_threads);
   }
-  /* The following free has to be done, even if my_thread_var() is 0 */
-#if !defined(__WIN__) || defined(USE_TLS)
   pthread_setspecific(THR_KEY_mysys,0);
-#endif
 }
 
 struct st_my_thread_var *_my_thread_var(void)

mysys/my_winthread.c

@@ -129,12 +129,5 @@ void pthread_exit(void *a)
   _endthread();
 }
 
-/* This is neaded to get the macro pthread_setspecific to work */
-
-int win_pthread_setspecific(void *a,void *b,uint length)
-{
-  memcpy(a,b,length);
-  return 0;
-}
 
 #endif

tests/CMakeLists.txt

@@ -13,7 +13,6 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
-# About "mysqlclient_notls", see note in "client/CMakeLists.txt"
 
 SET(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -DSAFEMALLOC -DSAFE_MUTEX")
 ADD_DEFINITIONS("-DMYSQL_CLIENT")
@@ -21,7 +20,7 @@ ADD_DEFINITIONS("-DMYSQL_CLIENT")
 INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/include)
 
 ADD_EXECUTABLE(mysql_client_test mysql_client_test.c ../mysys/my_memmem.c)
-TARGET_LINK_LIBRARIES(mysql_client_test mysqlclient_notls wsock32)
+TARGET_LINK_LIBRARIES(mysql_client_test mysqlclient wsock32)
 
 ADD_EXECUTABLE(bug25714 bug25714.c)
-TARGET_LINK_LIBRARIES(bug25714 mysqlclient_notls wsock32)
+TARGET_LINK_LIBRARIES(bug25714 mysqlclient wsock32)