src/mesa/glapi/glapi.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.1
   4  *
   5  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 /*
  27  * This file manages the OpenGL API dispatch layer.
  28  * The dispatch table (struct _glapi_table) is basically just a list
  29  * of function pointers.
  30  * There are functions to set/get the current dispatch table for the
  31  * current thread and to manage registration/dispatch of dynamically
  32  * added extension functions.
  33  *
  34  * It's intended that this file and the other glapi*.[ch] files are
  35  * flexible enough to be reused in several places:  XFree86, DRI-
  36  * based libGL.so, and perhaps the SGI SI.
  37  *
  38  * NOTE: There are no dependencies on Mesa in this code.
  39  *
  40  * Versions (API changes):
  41  *   2000/02/23  - original version for Mesa 3.3 and XFree86 4.0
  42  *   2001/01/16  - added dispatch override feature for Mesa 3.5
  43  *   2002/06/28  - added _glapi_set_warning_func(), Mesa 4.1.
  44  *   2002/10/01  - _glapi_get_proc_address() will now generate new entrypoints
  45  *                 itself (using offset ~0).  _glapi_add_entrypoint() can be
  46  *                 called afterward and it'll fill in the correct dispatch
  47  *                 offset.  This allows DRI libGL to avoid probing for DRI
  48  *                 drivers!  No changes to the public glapi interface.
  49  */
  50
  51
  52
  53 #ifdef HAVE_DIX_CONFIG_H
  54
  55 #include <dix-config.h>
  56 #define PUBLIC
  57
  58 #else
  59
  60 #include "main/glheader.h"
  61
  62 #endif
  63
  64 #include <stdlib.h>
  65 #include <string.h>
  66 #ifdef DEBUG
  67 #include <assert.h>
  68 #endif
  69
  70 #include "glapi.h"
  71 #include "glapioffsets.h"
  72 #include "glapitable.h"
  73
  74
  75 /***** BEGIN NO-OP DISPATCH *****/
  76
  77 static GLboolean WarnFlag = GL_FALSE;
  78 static _glapi_warning_func warning_func;
  79
  80 /*
  81  * Enable/disable printing of warning messages.
  82  */
  83 PUBLIC void
  84 _glapi_noop_enable_warnings(GLboolean enable)
  85 {
  86    WarnFlag = enable;
  87 }
  88
  89 /*
  90  * Register a callback function for reporting errors.
  91  */
  92 PUBLIC void
  93 _glapi_set_warning_func( _glapi_warning_func func )
  94 {
  95    warning_func = func;
  96 }
  97
  98 static GLboolean
  99 warn(void)
 100 {
 101 #if !defined(_WIN32_WCE)
 102    if ((WarnFlag || getenv("MESA_DEBUG") || getenv("LIBGL_DEBUG"))
 103        && warning_func) {
 104       return GL_TRUE;
 105    }
 106    else {
 107       return GL_FALSE;
 108    }
 109 #else
 110    return GL_FALSE;
 111 #endif
 112 }
 113
 114
 115 #define KEYWORD1 static
 116 #define KEYWORD1_ALT static
 117 #define KEYWORD2 GLAPIENTRY
 118 #define NAME(func)  NoOp##func
 119
 120 #define F NULL
 121
 122 #define DISPATCH(func, args, msg)                                             \
 123    if (warn()) {                                                              \
 124       warning_func(NULL, "GL User Error: called without context: %s", #func); \
 125    }
 126
 127 #define RETURN_DISPATCH(func, args, msg)                                      \
 128    if (warn()) {                                                              \
 129       warning_func(NULL, "GL User Error: called without context: %s", #func); \
 130    }                                                                          \
 131    return 0
 132
 133 #define DISPATCH_TABLE_NAME __glapi_noop_table
 134 #define UNUSED_TABLE_NAME __unused_noop_functions
 135
 136 #define TABLE_ENTRY(name) (_glapi_proc) NoOp##name
 137
 138 static GLint NoOpUnused(void)
 139 {
 140    if (warn()) {
 141       warning_func(NULL, "GL User Error: calling extension function without a current context\n");
 142    }
 143    return 0;
 144 }
 145
 146 #include "glapitemp.h"
 147
 148 /***** END NO-OP DISPATCH *****/
 149
 150
 151
 152 /**
 153  * \name Current dispatch and current context control variables
 154  *
 155  * Depending on whether or not multithreading is support, and the type of
 156  * support available, several variables are used to store the current context
 157  * pointer and the current dispatch table pointer.  In the non-threaded case,
 158  * the variables \c _glapi_Dispatch and \c _glapi_Context are used for this
 159  * purpose.
 160  *
 161  * In the "normal" threaded case, the variables \c _glapi_Dispatch and
 162  * \c _glapi_Context will be \c NULL if an application is detected as being
 163  * multithreaded.  Single-threaded applications will use \c _glapi_Dispatch
 164  * and \c _glapi_Context just like the case without any threading support.
 165  * When \c _glapi_Dispatch and \c _glapi_Context are \c NULL, the thread state
 166  * data \c _gl_DispatchTSD and \c ContextTSD are used.  Drivers and the
 167  * static dispatch functions access these variables via \c _glapi_get_dispatch
 168  * and \c _glapi_get_context.
 169  *
 170  * There is a race condition in setting \c _glapi_Dispatch to \c NULL.  It is
 171  * possible for the original thread to be setting it at the same instant a new
 172  * thread, perhaps running on a different processor, is clearing it.  Because
 173  * of that, \c ThreadSafe, which can only ever be changed to \c GL_TRUE, is
 174  * used to determine whether or not the application is multithreaded.
 175  *
 176  * In the TLS case, the variables \c _glapi_Dispatch and \c _glapi_Context are
 177  * hardcoded to \c NULL.  Instead the TLS variables \c _glapi_tls_Dispatch and
 178  * \c _glapi_tls_Context are used.  Having \c _glapi_Dispatch and
 179  * \c _glapi_Context be hardcoded to \c NULL maintains binary compatability
 180  * between TLS enabled loaders and non-TLS DRI drivers.
 181  */
 182 /*@{*/
 183 #if defined(GLX_USE_TLS)
 184
 185 PUBLIC __thread struct _glapi_table * _glapi_tls_Dispatch
 186     __attribute__((tls_model("initial-exec")))
 187     = (struct _glapi_table *) __glapi_noop_table;
 188
 189 PUBLIC __thread void * _glapi_tls_Context
 190     __attribute__((tls_model("initial-exec")));
 191
 192 PUBLIC const struct _glapi_table *_glapi_Dispatch = NULL;
 193 PUBLIC const void *_glapi_Context = NULL;
 194
 195 #else
 196
 197 #if defined(THREADS)
 198
 199 static GLboolean ThreadSafe = GL_FALSE;  /**< In thread-safe mode? */
 200 _glthread_TSD _gl_DispatchTSD;           /**< Per-thread dispatch pointer */
 201 static _glthread_TSD ContextTSD;         /**< Per-thread context pointer */
 202
 203 #if defined(WIN32_THREADS)
 204 void FreeTSD(_glthread_TSD *p);
 205 void FreeAllTSD(void)
 206 {
 207    FreeTSD(&_gl_DispatchTSD);
 208    FreeTSD(&ContextTSD);
 209 }
 210 #endif /* defined(WIN32_THREADS) */
 211
 212 #endif /* defined(THREADS) */
 213
 214 PUBLIC struct _glapi_table *_glapi_Dispatch =
 215   (struct _glapi_table *) __glapi_noop_table;
 216 PUBLIC void *_glapi_Context = NULL;
 217
 218 #endif /* defined(GLX_USE_TLS) */
 219 /*@}*/
 220
 221
 222
 223
 224 /**
 225  * We should call this periodically from a function such as glXMakeCurrent
 226  * in order to test if multiple threads are being used.
 227  */
 228 void
 229 _glapi_check_multithread(void)
 230 {
 231 #if defined(THREADS) && !defined(GLX_USE_TLS)
 232    if (!ThreadSafe) {
 233       static unsigned long knownID;
 234       static GLboolean firstCall = GL_TRUE;
 235       if (firstCall) {
 236          knownID = _glthread_GetID();
 237          firstCall = GL_FALSE;
 238       }
 239       else if (knownID != _glthread_GetID()) {
 240          ThreadSafe = GL_TRUE;
 241          _glapi_set_dispatch(NULL);
 242          _glapi_set_context(NULL);
 243       }
 244    }
 245    else if (!_glapi_get_dispatch()) {
 246       /* make sure that this thread's dispatch pointer isn't null */
 247       _glapi_set_dispatch(NULL);
 248    }
 249 #endif
 250 }
 251
 252
 253
 254 /**
 255  * Set the current context pointer for this thread.
 256  * The context pointer is an opaque type which should be cast to
 257  * void from the real context pointer type.
 258  */
 259 PUBLIC void
 260 _glapi_set_context(void *context)
 261 {
 262    (void) __unused_noop_functions; /* silence a warning */
 263 #if defined(GLX_USE_TLS)
 264    _glapi_tls_Context = context;
 265 #elif defined(THREADS)
 266    _glthread_SetTSD(&ContextTSD, context);
 267    _glapi_Context = (ThreadSafe) ? NULL : context;
 268 #else
 269    _glapi_Context = context;
 270 #endif
 271 }
 272
 273
 274
 275 /**
 276  * Get the current context pointer for this thread.
 277  * The context pointer is an opaque type which should be cast from
 278  * void to the real context pointer type.
 279  */
 280 PUBLIC void *
 281 _glapi_get_context(void)
 282 {
 283 #if defined(GLX_USE_TLS)
 284    return _glapi_tls_Context;
 285 #elif defined(THREADS)
 286    if (ThreadSafe) {
 287       return _glthread_GetTSD(&ContextTSD);
 288    }
 289    else {
 290       return _glapi_Context;
 291    }
 292 #else
 293    return _glapi_Context;
 294 #endif
 295 }
 296
 297 #ifdef USE_X86_ASM
 298
 299 #if defined( GLX_USE_TLS )
 300 extern       GLubyte gl_dispatch_functions_start[];
 301 extern       GLubyte gl_dispatch_functions_end[];
 302 #else
 303 extern const GLubyte gl_dispatch_functions_start[];
 304 #endif
 305
 306 #endif /* USE_X86_ASM */
 307
 308
 309 #if defined(USE_X64_64_ASM) && defined(GLX_USE_TLS)
 310 # define DISPATCH_FUNCTION_SIZE  16
 311 #elif defined(USE_X86_ASM)
 312 # if defined(THREADS) && !defined(GLX_USE_TLS)
 313 #  define DISPATCH_FUNCTION_SIZE  32
 314 # else
 315 #  define DISPATCH_FUNCTION_SIZE  16
 316 # endif
 317 #endif
 318
 319 #if !defined(DISPATCH_FUNCTION_SIZE) && !defined(XFree86Server) && !defined(XGLServer)
 320 # define NEED_FUNCTION_POINTER
 321 #endif
 322
 323 #if defined(PTHREADS) || defined(GLX_USE_TLS)
 324 /**
 325  * Perform platform-specific GL API entry-point fixups.
 326  */
 327 static void
 328 init_glapi_relocs( void )
 329 {
 330 #if defined(USE_X86_ASM) && defined(GLX_USE_TLS) && !defined(GLX_X86_READONLY_TEXT)
 331     extern unsigned long _x86_get_dispatch(void);
 332     char run_time_patch[] = {
 333        0x65, 0xa1, 0, 0, 0, 0 /* movl %gs:0,%eax */
 334     };
 335     GLuint *offset = (GLuint *) &run_time_patch[2]; /* 32-bits for x86/32 */
 336     const GLubyte * const get_disp = (const GLubyte *) run_time_patch;
 337     GLubyte * curr_func = (GLubyte *) gl_dispatch_functions_start;
 338
 339     *offset = _x86_get_dispatch();
 340     while ( curr_func != (GLubyte *) gl_dispatch_functions_end ) {
 341         (void) memcpy( curr_func, get_disp, sizeof(run_time_patch));
 342         curr_func += DISPATCH_FUNCTION_SIZE;
 343     }
 344 #endif
 345 }
 346 #endif /* defined(PTHREADS) || defined(GLX_USE_TLS) */
 347
 348
 349 /**
 350  * Set the global or per-thread dispatch table pointer.
 351  * If the dispatch parameter is NULL we'll plug in the no-op dispatch
 352  * table (__glapi_noop_table).
 353  */
 354 PUBLIC void
 355 _glapi_set_dispatch(struct _glapi_table *dispatch)
 356 {
 357 #if defined(PTHREADS) || defined(GLX_USE_TLS)
 358    static pthread_once_t once_control = PTHREAD_ONCE_INIT;
 359    pthread_once( & once_control, init_glapi_relocs );
 360 #endif
 361
 362    if (!dispatch) {
 363       /* use the no-op functions */
 364       dispatch = (struct _glapi_table *) __glapi_noop_table;
 365    }
 366 #ifdef DEBUG
 367    else {
 368       _glapi_check_table(dispatch);
 369    }
 370 #endif
 371
 372 #if defined(GLX_USE_TLS)
 373    _glapi_tls_Dispatch = dispatch;
 374 #elif defined(THREADS)
 375    _glthread_SetTSD(&_gl_DispatchTSD, (void *) dispatch);
 376    _glapi_Dispatch = (ThreadSafe) ? NULL : dispatch;
 377 #else /*THREADS*/
 378    _glapi_Dispatch = dispatch;
 379 #endif /*THREADS*/
 380 }
 381
 382
 383
 384 /**
 385  * Return pointer to current dispatch table for calling thread.
 386  */
 387 PUBLIC struct _glapi_table *
 388 _glapi_get_dispatch(void)
 389 {
 390    struct _glapi_table * api;
 391 #if defined(GLX_USE_TLS)
 392    api = _glapi_tls_Dispatch;
 393 #elif defined(THREADS)
 394    api = (ThreadSafe)
 395      ? (struct _glapi_table *) _glthread_GetTSD(&_gl_DispatchTSD)
 396      : _glapi_Dispatch;
 397 #else
 398    api = _glapi_Dispatch;
 399 #endif
 400    return api;
 401 }
 402
 403
 404
 405
 406 /*
 407  * The dispatch table size (number of entries) is the size of the
 408  * _glapi_table struct plus the number of dynamic entries we can add.
 409  * The extra slots can be filled in by DRI drivers that register new extension
 410  * functions.
 411  */
 412 #define DISPATCH_TABLE_SIZE (sizeof(struct _glapi_table) / sizeof(void *) + MAX_EXTENSION_FUNCS)
 413
 414
 415 /**
 416  * Return size of dispatch table struct as number of functions (or
 417  * slots).
 418  */
 419 PUBLIC GLuint
 420 _glapi_get_dispatch_table_size(void)
 421 {
 422    return DISPATCH_TABLE_SIZE;
 423 }
 424
 425
 426 /**
 427  * Make sure there are no NULL pointers in the given dispatch table.
 428  * Intended for debugging purposes.
 429  */
 430 void
 431 _glapi_check_table(const struct _glapi_table *table)
 432 {
 433 #ifdef EXTRA_DEBUG
 434    const GLuint entries = _glapi_get_dispatch_table_size();
 435    const void **tab = (const void **) table;
 436    GLuint i;
 437    for (i = 1; i < entries; i++) {
 438       assert(tab[i]);
 439    }
 440
 441    /* Do some spot checks to be sure that the dispatch table
 442     * slots are assigned correctly.
 443     */
 444    {
 445       GLuint BeginOffset = _glapi_get_proc_offset("glBegin");
 446       char *BeginFunc = (char*) &table->Begin;
 447       GLuint offset = (BeginFunc - (char *) table) / sizeof(void *);
 448       assert(BeginOffset == _gloffset_Begin);
 449       assert(BeginOffset == offset);
 450    }
 451    {
 452       GLuint viewportOffset = _glapi_get_proc_offset("glViewport");
 453       char *viewportFunc = (char*) &table->Viewport;
 454       GLuint offset = (viewportFunc - (char *) table) / sizeof(void *);
 455       assert(viewportOffset == _gloffset_Viewport);
 456       assert(viewportOffset == offset);
 457    }
 458    {
 459       GLuint VertexPointerOffset = _glapi_get_proc_offset("glVertexPointer");
 460       char *VertexPointerFunc = (char*) &table->VertexPointer;
 461       GLuint offset = (VertexPointerFunc - (char *) table) / sizeof(void *);
 462       assert(VertexPointerOffset == _gloffset_VertexPointer);
 463       assert(VertexPointerOffset == offset);
 464    }
 465    {
 466       GLuint ResetMinMaxOffset = _glapi_get_proc_offset("glResetMinmax");
 467       char *ResetMinMaxFunc = (char*) &table->ResetMinmax;
 468       GLuint offset = (ResetMinMaxFunc - (char *) table) / sizeof(void *);
 469       assert(ResetMinMaxOffset == _gloffset_ResetMinmax);
 470       assert(ResetMinMaxOffset == offset);
 471    }
 472    {
 473       GLuint blendColorOffset = _glapi_get_proc_offset("glBlendColor");
 474       char *blendColorFunc = (char*) &table->BlendColor;
 475       GLuint offset = (blendColorFunc - (char *) table) / sizeof(void *);
 476       assert(blendColorOffset == _gloffset_BlendColor);
 477       assert(blendColorOffset == offset);
 478    }
 479    {
 480       GLuint secondaryColor3fOffset = _glapi_get_proc_offset("glSecondaryColor3fEXT");
 481       char *secondaryColor3fFunc = (char*) &table->SecondaryColor3fEXT;
 482       GLuint offset = (secondaryColor3fFunc - (char *) table) / sizeof(void *);
 483       assert(secondaryColor3fOffset == _gloffset_SecondaryColor3fEXT);
 484       assert(secondaryColor3fOffset == offset);
 485    }
 486    {
 487       GLuint pointParameterivOffset = _glapi_get_proc_offset("glPointParameterivNV");
 488       char *pointParameterivFunc = (char*) &table->PointParameterivNV;
 489       GLuint offset = (pointParameterivFunc - (char *) table) / sizeof(void *);
 490       assert(pointParameterivOffset == _gloffset_PointParameterivNV);
 491       assert(pointParameterivOffset == offset);
 492    }
 493    {
 494       GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
 495       char *setFenceFunc = (char*) &table->SetFenceNV;
 496       GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
 497       assert(setFenceOffset == _gloffset_SetFenceNV);
 498       assert(setFenceOffset == offset);
 499    }
 500 #else
 501    (void) table;
 502 #endif
 503 }