1 // @(#)root/thread:$Id$
2 /*
3 * Copyright (c) 2006-2011 High Performance Computing Center Stuttgart,
4 * University of Stuttgart. All rights reserved.
5 * Author: Rainer Keller, HLRS
6 * Modified: Fons Rademakers, CERN
7 * Modified: Philippe Canal, FNAL
8 *
9 * Thread-local storage (TLS) is not supported on all environments.
10 * This header file and test-program shows how to abstract away, using either
11 * __thread,
12 * __declspec(thread),
13 * thread_local or
14 * Pthread-Keys
15 * depending on the (configure-set) CPP-variables R__HAS___THREAD,
16 * R__HAS_DECLSPEC_THREAD, R__HAS_THREAD_LOCAL or R__HAS_PTHREAD.
17 *
18 * Use the macros TTHREAD_TLS_DECLARE, TTHREAD_TLS_INIT, and the
19 * getters and setters TTHREAD_TLS_GET and TTHREAD_TLS_GET
20 * to work on the declared variables.
21 *
22 * In case of PThread keys, we need to resolve to using keys!
23 * In order to do so, we need to declare and access
24 * TLS variables through three macros:
25 * - TTHREAD_TLS_DECLARE
26 * - TTHREAD_TLS_INIT
27 * - TTHREAD_TLS_SET and
28 * - TTHREAD_TLS_GET
29 * We do depend on the following (GCC-)extension:
30 * - In case of function-local static functions,
31 * we declare a sub-function to create a specific key.
32 * Unfortunately, we do NOT use the following extensions:
33 * - Using typeof, we could get rid of the type-declaration
34 * which is used for casting, however typeof is not ANSI C.
35 * - We do NOT allow something like
36 * func (a, TTHREAD_TLS_SET(int, my_var, 5));
37 * as we do not use the gcc-extension of returning macro-values.
38 */
39
40 #ifndef ROOT_ThreadLocalStorage
41 #define ROOT_ThreadLocalStorage
42
43 #ifndef ROOT_RConfig
44 #include "RConfig.h"
45 #endif
46
47 #ifndef ROOT_RConfigure
48 #include "RConfigure.h"
49 #endif
50
51 #if defined(R__MACOSX)
52 # if defined(__clang__) && defined(MAC_OS_X_VERSION_10_7) && (defined(__x86_64__) || defined(__i386__))
53 # define R__HAS___THREAD
54 # elif !defined(R__HAS_PTHREAD)
55 # define R__HAS_PTHREAD
56 # endif
57 #endif
58 #if defined(R__LINUX) || defined(R__AIX)
59 # define R__HAS___THREAD
60 #endif
61 #if defined(R__SOLARIS) && !defined(R__HAS_PTHREAD)
62 # define R__HAS_PTHREAD
63 #endif
64 #if defined(R__WIN32)
65 # define R__HAS_DECLSPEC_THREAD
66 #endif
67
68 #if __cplusplus >= 201103L
69
70 // Note: it would be tempting to use __has_feature(cxx_thread_local) but despite
71 // documentation claims it support for it ... it is in fact ineffective (return
72 // a false negative).
73 // Clang 3.4 also support SD-6 (feature test macros __cpp_*), but no thread local macro
74 # if defined(__clang__) && (__clang_major__ >= 3 && __clang_minor__ >= 3)
75 // thread_local was added in Clang 3.3
76 // Still requires libstdc++ from GCC 4.8
77 // For that __GLIBCXX__ isn't good enough
78 # define R__HAS_THREAD_LOCAL
79
80 # elif defined(__GNUG__) && (__GNUC__ <= 4 && __GNUC_MINOR__ < 80)
81 // The C++11 thread_local keyword is supported in GCC only since 4.8
82 # define R__HAS___THREAD
83 # else
84 # define R__HAS_THREAD_LOCAL
85 # endif
86
87 #endif
88
89
90 #ifdef __cplusplus
91
92 // Note that the order is relevant, more than one of the flag might be
93 // on at the same time and we want to use 'best' option available.
94
95 #ifdef __CINT__
96
97 # define TTHREAD_TLS(type) static type
98 # define TTHREAD_TLS_ARRAY(type,size,name) static type name[size];
99 # define TTHREAD_TLS_PTR(name) &name
100
101 #elif defined(R__HAS_THREAD_LOCAL)
102
103 # define TTHREAD_TLS(type) thread_local type
104 # define TTHREAD_TLS_ARRAY(type,size,name) thread_local type name[size];
105 # define TTHREAD_TLS_PTR(name) &name
106
107 #elif defined(R__HAS___THREAD)
108
109 # define TTHREAD_TLS(type) static __thread type
110 # define TTHREAD_TLS_ARRAY(type,size,name) static __thread type name[size];
111 # define TTHREAD_TLS_PTR(name) &name
112
113 #elif defined(R__HAS_DECLSPEC_THREAD)
114
115 # define TTHREAD_TLS(type) static __declspec(thread) type
116 # define TTHREAD_TLS_ARRAY(type,size,name) static __declspec(thread) type name[size];
117 # define TTHREAD_TLS_PTR(name) &name
118
119 #elif defined(R__HAS_PTHREAD)
120
121 #include <assert.h>
122 #include <pthread.h>
123
124 template <typename type> class TThreadTLSWrapper
125 {
126 private:
127 pthread_key_t fKey;
128 type fInitValue;
129
130 static void key_delete(void *arg) {
131 assert (NULL != arg);
132 delete (type*)(arg);
133 }
134
135 public:
136
137 TThreadTLSWrapper() : fInitValue() {
138
139 pthread_key_create(&(fKey), key_delete);
140 }
141
142 TThreadTLSWrapper(const type &value) : fInitValue(value) {
143
144 pthread_key_create(&(fKey), key_delete);
145 }
146
147 ~TThreadTLSWrapper() {
148 pthread_key_delete(fKey);
149 }
150
151 type& get() {
152 void *ptr = pthread_getspecific(fKey);
153 if (!ptr) {
154 ptr = new type(fInitValue);
155 assert (NULL != ptr);
156 (void) pthread_setspecific(fKey, ptr);
157 }
158 return *(type*)ptr;
159 }
160
161 type& operator=(const type &in) {
162 type &ptr = get();
163 ptr = in;
164 return ptr;
165 }
166
167 operator type&() {
168 return get();
169 }
170
171 };
172
173 template <typename type,int size> class TThreadTLSArrayWrapper
174 {
175 private:
176 pthread_key_t fKey;
177
178 static void key_delete(void *arg) {
179 assert (NULL != arg);
180 delete [] (type*)(arg);
181 }
182
183 public:
184
185 TThreadTLSArrayWrapper() {
186
187 pthread_key_create(&(fKey), key_delete);
188 }
189
190 ~TThreadTLSArrayWrapper() {
191 pthread_key_delete(fKey);
192 }
193
194 type* get() {
195 void *ptr = pthread_getspecific(fKey);
196 if (!ptr) {
197 ptr = new type[size];
198 assert (NULL != ptr);
199 (void) pthread_setspecific(fKey, ptr);
200 }
201 return (type*)ptr;
202 }
203
204 // type& operator=(const type &in) {
205 // type &ptr = get();
206 // ptr = in;
207 // return ptr;
208 // }
209 //
210 operator type*() {
211 return get();
212 }
213
214 };
215
216 # define TTHREAD_TLS(type) static TThreadTLSWrapper<type>
217 # define TTHREAD_TLS_ARRAY(type,size,name) static TThreadTLSArrayWrapper<type,size> name;
218 # define TTHREAD_TLS_PTR(name) &(name.get())
219 #else
220
221 #error "No Thread Local Storage (TLS) technology for this platform specified."
222
223 #endif
224
225 // Available on all platforms
226 template <int marker, typename T>
227 T &TTHREAD_TLS_INIT() {
228 TTHREAD_TLS(T*) ptr = NULL;
229 TTHREAD_TLS(Bool_t) isInit(kFALSE);
230 if (!isInit) {
231 ptr = new T;
232 isInit = kTRUE;
233 }
234 return *ptr;
235 }
236
237 template <int marker, typename Array, typename T>
238 Array &TTHREAD_TLS_INIT_ARRAY() {
239 TTHREAD_TLS(Array*) ptr = NULL;
240 TTHREAD_TLS(Bool_t) isInit(kFALSE);
241 if (!isInit) {
242 ptr = new Array[sizeof(Array)/sizeof(T)];
243 isInit = kTRUE;
244 }
245 return *ptr;
246 }
247
248 template <int marker, typename T, typename ArgType>
249 T &TTHREAD_TLS_INIT(ArgType arg) {
250 TTHREAD_TLS(T*) ptr = NULL;
251 TTHREAD_TLS(Bool_t) isInit(kFALSE);
252 if (!isInit) {
253 ptr = new T(arg);
254 isInit = kTRUE;
255 }
256 return *ptr;
257 }
258
259 #else // __cplusplus
260
261 #if defined(R__HAS_THREAD_LOCAL)
262
263 # define TTHREAD_TLS_DECLARE(type,name)
264 # define TTHREAD_TLS_INIT(type,name,value) thread_local type name = (value)
265 # define TTHREAD_TLS_SET(type,name,value) name = (value)
266 # define TTHREAD_TLS_GET(type,name) (name)
267 # define TTHREAD_TLS_FREE(name)
268
269 #elif defined(R__HAS___THREAD)
270
271 # define TTHREAD_TLS_DECLARE(type,name)
272 # define TTHREAD_TLS_INIT(type,name,value) static __thread type name = (value)
273 # define TTHREAD_TLS_SET(type,name,value) name = (value)
274 # define TTHREAD_TLS_GET(type,name) (name)
275 # define TTHREAD_TLS_FREE(name)
276
277 #elif defined(R__HAS_DECLSPEC_THREAD)
278
279 # define TTHREAD_TLS_DECLARE(type,name)
280 # define TTHREAD_TLS_INIT(type,name,value) static __declspec(thread) type name = (value)
281 # define TTHREAD_TLS_SET(type,name,value) name = (value)
282 # define TTHREAD_TLS_GET(type,name) (name)
283 # define TTHREAD_TLS_FREE(name)
284
285 #elif defined(R__HAS_PTHREAD)
286
287 #include <assert.h>
288 #include <pthread.h>
289
290 # define TTHREAD_TLS_DECLARE(type,name) \
291 static pthread_key_t _##name##_key; \
292 static void _##name##_key_delete(void * arg) \
293 { \
294 assert (NULL != arg); \
295 free(arg); \
296 } \
297 static void _##name##_key_create(void) \
298 { \
299 int _ret; \
300 _ret = pthread_key_create(&(_##name##_key), _##name##_key_delete); \
301 _ret = _ret; /* To get rid of warnings in case of NDEBUG */ \
302 assert (0 == _ret); \
303 } \
304 static pthread_once_t _##name##_once = PTHREAD_ONCE_INIT;
305
306 # define TTHREAD_TLS_INIT(type,name,value) \
307 do { \
308 void *_ptr; \
309 (void) pthread_once(&(_##name##_once), _##name##_key_create); \
310 if ((_ptr = pthread_getspecific(_##name##_key)) == NULL) { \
311 _ptr = malloc(sizeof(type)); \
312 assert (NULL != _ptr); \
313 (void) pthread_setspecific(_##name##_key, _ptr); \
314 *((type*)_ptr) = (value); \
315 } \
316 } while (0)
317
318 # define TTHREAD_TLS_SET(type,name,value) \
319 do { \
320 void *_ptr = pthread_getspecific(_##name##_key); \
321 assert (NULL != _ptr); \
322 *((type*)_ptr) = (value); \
323 } while (0)
324
325 # define TTHREAD_TLS_GET(type,name) \
326 *((type*)pthread_getspecific(_##name##_key))
327
328 # define TTHREAD_TLS_FREE(name) \
329 pthread_key_delete(_##name##_key);
330
331 #else
332
333 #error "No Thread Local Storage (TLS) technology for this platform specified."
334
335 #endif
336
337 #endif // __cplusplus
338
339 #endif
340
341