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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *  * Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  *  * Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in
     12  *    the documentation and/or other materials provided with the
     13  *    distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #ifndef _BIONIC_THREAD_LOCAL_BUFFER_H_included
     30 #define _BIONIC_THREAD_LOCAL_BUFFER_H_included
     31 
     32 #include <malloc.h>
     33 #include <pthread.h>
     34 
     35 // libstdc++ currently contains __cxa_guard_acquire and __cxa_guard_release,
     36 // so we make do with macros instead of a C++ class.
     37 // TODO: move __cxa_guard_acquire and __cxa_guard_release into libc.
     38 
     39 // We used to use pthread_once to initialize the keys, but life is more predictable
     40 // if we allocate them all up front when the C library starts up, via __constructor__.
     41 
     42 #define GLOBAL_INIT_THREAD_LOCAL_BUFFER(name) \
     43   static pthread_key_t __bionic_tls_ ## name ## _key; \
     44   static void __bionic_tls_ ## name ## _key_destroy(void* buffer) { \
     45     free(buffer); \
     46   } \
     47   __attribute__((constructor)) static void __bionic_tls_ ## name ## _key_init() { \
     48     pthread_key_create(&__bionic_tls_ ## name ## _key, __bionic_tls_ ## name ## _key_destroy); \
     49   }
     50 
     51 // Leaves "name_tls_buffer" and "name_tls_buffer_size" defined and initialized.
     52 #define LOCAL_INIT_THREAD_LOCAL_BUFFER(type, name, byte_count) \
     53   type name ## _tls_buffer = \
     54       reinterpret_cast<type>(pthread_getspecific(__bionic_tls_ ## name ## _key)); \
     55   if (name ## _tls_buffer == NULL) { \
     56     name ## _tls_buffer = reinterpret_cast<type>(calloc(1, byte_count)); \
     57     pthread_setspecific(__bionic_tls_ ## name ## _key, name ## _tls_buffer); \
     58   } \
     59   const size_t name ## _tls_buffer_size __attribute__((unused)) = byte_count
     60 
     61 #endif // _BIONIC_THREAD_LOCAL_BUFFER_H_included
     62