/* * Mesa 3-D graphics library * Version: 7.1 * * 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 * BRIAN PAUL 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. */ #ifdef HAVE_DIX_CONFIG_H #include #include "glapi/mesa.h" #else #include "main/glheader.h" #include "main/compiler.h" #endif #include "glapi/glapi.h" #include "glapi/glapitable.h" extern _glapi_proc __glapi_noop_table[]; /** * \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) PUBLIC __thread struct _glapi_table * _glapi_tls_Dispatch __attribute__((tls_model("initial-exec"))) = (struct _glapi_table *) __glapi_noop_table; PUBLIC __thread void * _glapi_tls_Context __attribute__((tls_model("initial-exec"))); PUBLIC const struct _glapi_table *_glapi_Dispatch = NULL; PUBLIC const void *_glapi_Context = NULL; #else #if defined(THREADS) static GLboolean ThreadSafe = GL_FALSE; /**< In thread-safe mode? */ _glthread_TSD _gl_DispatchTSD; /**< Per-thread dispatch pointer */ static _glthread_TSD ContextTSD; /**< Per-thread context pointer */ #endif /* defined(THREADS) */ PUBLIC struct _glapi_table *_glapi_Dispatch = (struct _glapi_table *) __glapi_noop_table; PUBLIC void *_glapi_Context = NULL; #endif /* defined(GLX_USE_TLS) */ /*@}*/ #if defined(THREADS) && !defined(GLX_USE_TLS) void _glapi_init_multithread(void) { _glthread_InitTSD(&_gl_DispatchTSD); _glthread_InitTSD(&ContextTSD); } void _glapi_destroy_multithread(void) { #ifdef WIN32_THREADS _glthread_DestroyTSD(&_gl_DispatchTSD); _glthread_DestroyTSD(&ContextTSD); #endif } /** * Mutex for multithread check. */ #ifdef WIN32_THREADS /* _glthread_DECLARE_STATIC_MUTEX is broken on windows. There will be race! */ #define CHECK_MULTITHREAD_LOCK() #define CHECK_MULTITHREAD_UNLOCK() #else _glthread_DECLARE_STATIC_MUTEX(ThreadCheckMutex); #define CHECK_MULTITHREAD_LOCK() _glthread_LOCK_MUTEX(ThreadCheckMutex) #define CHECK_MULTITHREAD_UNLOCK() _glthread_UNLOCK_MUTEX(ThreadCheckMutex) #endif /** * We should call this periodically from a function such as glXMakeCurrent * in order to test if multiple threads are being used. */ PUBLIC void _glapi_check_multithread(void) { static unsigned long knownID; static GLboolean firstCall = GL_TRUE; if (ThreadSafe) return; CHECK_MULTITHREAD_LOCK(); if (firstCall) { _glapi_init_multithread(); knownID = _glthread_GetID(); firstCall = GL_FALSE; } else if (knownID != _glthread_GetID()) { ThreadSafe = GL_TRUE; _glapi_set_dispatch(NULL); _glapi_set_context(NULL); } CHECK_MULTITHREAD_UNLOCK(); } #else void _glapi_init_multithread(void) { } void _glapi_destroy_multithread(void) { } PUBLIC void _glapi_check_multithread(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. */ PUBLIC void _glapi_set_context(void *context) { #if defined(GLX_USE_TLS) _glapi_tls_Context = context; #elif defined(THREADS) _glthread_SetTSD(&ContextTSD, context); _glapi_Context = (ThreadSafe) ? NULL : context; #else _glapi_Context = context; #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. */ PUBLIC void * _glapi_get_context(void) { #if defined(GLX_USE_TLS) return _glapi_tls_Context; #elif defined(THREADS) return (ThreadSafe) ? _glthread_GetTSD(&ContextTSD) : _glapi_Context; #else return _glapi_Context; #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). */ PUBLIC void _glapi_set_dispatch(struct _glapi_table *dispatch) { init_glapi_relocs_once(); if (dispatch == NULL) { /* use the no-op functions */ dispatch = (struct _glapi_table *) __glapi_noop_table; } #ifdef DEBUG else { _glapi_check_table_not_null(dispatch); _glapi_check_table(dispatch); } #endif #if defined(GLX_USE_TLS) _glapi_tls_Dispatch = dispatch; #elif defined(THREADS) _glthread_SetTSD(&_gl_DispatchTSD, (void *) dispatch); _glapi_Dispatch = (ThreadSafe) ? NULL : dispatch; #else _glapi_Dispatch = dispatch; #endif } /** * Return pointer to current dispatch table for calling thread. */ PUBLIC struct _glapi_table * _glapi_get_dispatch(void) { #if defined(GLX_USE_TLS) return _glapi_tls_Dispatch; #elif defined(THREADS) return (ThreadSafe) ? (struct _glapi_table *) _glthread_GetTSD(&_gl_DispatchTSD) : _glapi_Dispatch; #else return _glapi_Dispatch; #endif } /* * The dispatch table size (number of entries) is the size of the * _glapi_table struct plus the number of dynamic entries we can add. * The extra slots can be filled in by DRI drivers that register new extension * functions. */ #define DISPATCH_TABLE_SIZE (sizeof(struct _glapi_table) / sizeof(void *) + MAX_EXTENSION_FUNCS) /** * Return size of dispatch table struct as number of functions (or * slots). */ PUBLIC GLuint _glapi_get_dispatch_table_size(void) { return DISPATCH_TABLE_SIZE; } /** * Make sure there are no NULL pointers in the given dispatch table. * Intended for debugging purposes. */ void _glapi_check_table_not_null(const struct _glapi_table *table) { #if 0 /* enable this for extra DEBUG */ const GLuint entries = _glapi_get_dispatch_table_size(); const void **tab = (const void **) table; GLuint i; for (i = 1; i < entries; i++) { assert(tab[i]); } #else (void) table; #endif }