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| /* |
| * Mesa 3-D graphics library |
| * |
| * Copyright (C) 1999-2008 Brian Paul All Rights Reserved. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| * to deal in the Software without restriction, including without limitation |
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| * and/or sell copies of the Software, and to permit persons to whom the |
| * Software is furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included |
| * in all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS |
| * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR |
| * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, |
| * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
| * OTHER DEALINGS IN THE SOFTWARE. |
| */ |
| |
| |
| /* |
| * This file manages the OpenGL API dispatch layer. |
| * The dispatch table (struct _glapi_table) is basically just a list |
| * of function pointers. |
| * There are functions to set/get the current dispatch table for the |
| * current thread and to manage registration/dispatch of dynamically |
| * added extension functions. |
| * |
| * It's intended that this file and the other glapi*.[ch] files are |
| * flexible enough to be reused in several places: XFree86, DRI- |
| * based libGL.so, and perhaps the SGI SI. |
| * |
| * NOTE: There are no dependencies on Mesa in this code. |
| * |
| * Versions (API changes): |
| * 2000/02/23 - original version for Mesa 3.3 and XFree86 4.0 |
| * 2001/01/16 - added dispatch override feature for Mesa 3.5 |
| * 2002/06/28 - added _glapi_set_warning_func(), Mesa 4.1. |
| * 2002/10/01 - _glapi_get_proc_address() will now generate new entrypoints |
| * itself (using offset ~0). _glapi_add_entrypoint() can be |
| * called afterward and it'll fill in the correct dispatch |
| * offset. This allows DRI libGL to avoid probing for DRI |
| * drivers! No changes to the public glapi interface. |
| */ |
| |
| #include "u_current.h" |
| #include "u_thread.h" |
| |
| #ifndef MAPI_MODE_UTIL |
| |
| #include "table.h" |
| #include "stub.h" |
| |
| #else |
| |
| extern void init_glapi_relocs_once(void); |
| extern void (*__glapi_noop_table[])(void); |
| |
| #define table_noop_array __glapi_noop_table |
| #define stub_init_once() init_glapi_relocs_once() |
| |
| #endif |
| |
| /** |
| * \name Current dispatch and current context control variables |
| * |
| * Depending on whether or not multithreading is support, and the type of |
| * support available, several variables are used to store the current context |
| * pointer and the current dispatch table pointer. In the non-threaded case, |
| * the variables \c _glapi_Dispatch and \c _glapi_Context are used for this |
| * purpose. |
| * |
| * In the "normal" threaded case, the variables \c _glapi_Dispatch and |
| * \c _glapi_Context will be \c NULL if an application is detected as being |
| * multithreaded. Single-threaded applications will use \c _glapi_Dispatch |
| * and \c _glapi_Context just like the case without any threading support. |
| * When \c _glapi_Dispatch and \c _glapi_Context are \c NULL, the thread state |
| * data \c _gl_DispatchTSD and \c ContextTSD are used. Drivers and the |
| * static dispatch functions access these variables via \c _glapi_get_dispatch |
| * and \c _glapi_get_context. |
| * |
| * There is a race condition in setting \c _glapi_Dispatch to \c NULL. It is |
| * possible for the original thread to be setting it at the same instant a new |
| * thread, perhaps running on a different processor, is clearing it. Because |
| * of that, \c ThreadSafe, which can only ever be changed to \c GL_TRUE, is |
| * used to determine whether or not the application is multithreaded. |
| * |
| * In the TLS case, the variables \c _glapi_Dispatch and \c _glapi_Context are |
| * hardcoded to \c NULL. Instead the TLS variables \c _glapi_tls_Dispatch and |
| * \c _glapi_tls_Context are used. Having \c _glapi_Dispatch and |
| * \c _glapi_Context be hardcoded to \c NULL maintains binary compatability |
| * between TLS enabled loaders and non-TLS DRI drivers. |
| */ |
| /*@{*/ |
| #if defined(GLX_USE_TLS) |
| |
| __thread struct mapi_table *u_current_table |
| __attribute__((tls_model("initial-exec"))) |
| = (struct mapi_table *) table_noop_array; |
| |
| __thread void *u_current_user |
| __attribute__((tls_model("initial-exec"))); |
| |
| #else |
| |
| struct mapi_table *u_current_table = |
| (struct mapi_table *) table_noop_array; |
| void *u_current_user; |
| |
| #ifdef THREADS |
| struct u_tsd u_current_table_tsd; |
| static struct u_tsd u_current_user_tsd; |
| static int ThreadSafe; |
| #endif /* THREADS */ |
| |
| #endif /* defined(GLX_USE_TLS) */ |
| /*@}*/ |
| |
| |
| void |
| u_current_destroy(void) |
| { |
| #if defined(THREADS) && defined(_WIN32) |
| u_tsd_destroy(&u_current_table_tsd); |
| u_tsd_destroy(&u_current_user_tsd); |
| #endif |
| } |
| |
| |
| #if defined(THREADS) && !defined(GLX_USE_TLS) |
| |
| static void |
| u_current_init_tsd(void) |
| { |
| u_tsd_init(&u_current_table_tsd); |
| u_tsd_init(&u_current_user_tsd); |
| } |
| |
| /** |
| * Mutex for multithread check. |
| */ |
| u_mutex_declare_static(ThreadCheckMutex); |
| |
| /** |
| * We should call this periodically from a function such as glXMakeCurrent |
| * in order to test if multiple threads are being used. |
| */ |
| void |
| u_current_init(void) |
| { |
| static unsigned long knownID; |
| static int firstCall = 1; |
| |
| if (ThreadSafe) |
| return; |
| |
| u_mutex_lock(ThreadCheckMutex); |
| if (firstCall) { |
| u_current_init_tsd(); |
| |
| knownID = u_thread_self(); |
| firstCall = 0; |
| } |
| else if (knownID != u_thread_self()) { |
| ThreadSafe = 1; |
| u_current_set(NULL); |
| u_current_set_user(NULL); |
| } |
| u_mutex_unlock(ThreadCheckMutex); |
| } |
| |
| #else |
| |
| void |
| u_current_init(void) |
| { |
| } |
| |
| #endif |
| |
| |
| |
| /** |
| * Set the current context pointer for this thread. |
| * The context pointer is an opaque type which should be cast to |
| * void from the real context pointer type. |
| */ |
| void |
| u_current_set_user(const void *ptr) |
| { |
| u_current_init(); |
| |
| #if defined(GLX_USE_TLS) |
| u_current_user = (void *) ptr; |
| #elif defined(THREADS) |
| u_tsd_set(&u_current_user_tsd, (void *) ptr); |
| u_current_user = (ThreadSafe) ? NULL : (void *) ptr; |
| #else |
| u_current_user = (void *) ptr; |
| #endif |
| } |
| |
| /** |
| * Get the current context pointer for this thread. |
| * The context pointer is an opaque type which should be cast from |
| * void to the real context pointer type. |
| */ |
| void * |
| u_current_get_user_internal(void) |
| { |
| #if defined(GLX_USE_TLS) |
| return u_current_user; |
| #elif defined(THREADS) |
| return (ThreadSafe) |
| ? u_tsd_get(&u_current_user_tsd) |
| : u_current_user; |
| #else |
| return u_current_user; |
| #endif |
| } |
| |
| /** |
| * Set the global or per-thread dispatch table pointer. |
| * If the dispatch parameter is NULL we'll plug in the no-op dispatch |
| * table (__glapi_noop_table). |
| */ |
| void |
| u_current_set(const struct mapi_table *tbl) |
| { |
| u_current_init(); |
| |
| stub_init_once(); |
| |
| if (!tbl) |
| tbl = (const struct mapi_table *) table_noop_array; |
| |
| #if defined(GLX_USE_TLS) |
| u_current_table = (struct mapi_table *) tbl; |
| #elif defined(THREADS) |
| u_tsd_set(&u_current_table_tsd, (void *) tbl); |
| u_current_table = (ThreadSafe) ? NULL : (void *) tbl; |
| #else |
| u_current_table = (struct mapi_table *) tbl; |
| #endif |
| } |
| |
| /** |
| * Return pointer to current dispatch table for calling thread. |
| */ |
| struct mapi_table * |
| u_current_get_internal(void) |
| { |
| #if defined(GLX_USE_TLS) |
| return u_current_table; |
| #elif defined(THREADS) |
| return (struct mapi_table *) ((ThreadSafe) ? |
| u_tsd_get(&u_current_table_tsd) : (void *) u_current_table); |
| #else |
| return u_current_table; |
| #endif |
| } |