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 ((WarnFlag || getenv("MESA_DEBUG") || getenv("LIBGL_DEBUG"))
 102        && warning_func) {
 103       return GL_TRUE;
 104    }
 105    else {
 106       return GL_FALSE;
 107    }
 108 }
 109
 110
 111 #define KEYWORD1 static
 112 #define KEYWORD1_ALT static
 113 #define KEYWORD2 GLAPIENTRY
 114 #define NAME(func)  NoOp##func
 115
 116 #define F NULL
 117
 118 #define DISPATCH(func, args, msg)                                             \
 119    if (warn()) {                                                              \
 120       warning_func(NULL, "GL User Error: called without context: %s", #func); \
 121    }
 122
 123 #define RETURN_DISPATCH(func, args, msg)                                      \
 124    if (warn()) {                                                              \
 125       warning_func(NULL, "GL User Error: called without context: %s", #func); \
 126    }                                                                          \
 127    return 0
 128
 129 #define DISPATCH_TABLE_NAME __glapi_noop_table
 130 #define UNUSED_TABLE_NAME __unused_noop_functions
 131
 132 #define TABLE_ENTRY(name) (_glapi_proc) NoOp##name
 133
 134 static GLint NoOpUnused(void)
 135 {
 136    if (warn()) {
 137       warning_func(NULL, "GL User Error: calling extension function without a current context\n");
 138    }
 139    return 0;
 140 }
 141
 142 #include "glapitemp.h"
 143
 144 /***** END NO-OP DISPATCH *****/
 145
 146
 147
 148 /**
 149  * \name Current dispatch and current context control variables
 150  *
 151  * Depending on whether or not multithreading is support, and the type of
 152  * support available, several variables are used to store the current context
 153  * pointer and the current dispatch table pointer.  In the non-threaded case,
 154  * the variables \c _glapi_Dispatch and \c _glapi_Context are used for this
 155  * purpose.
 156  *
 157  * In the "normal" threaded case, the variables \c _glapi_Dispatch and
 158  * \c _glapi_Context will be \c NULL if an application is detected as being
 159  * multithreaded.  Single-threaded applications will use \c _glapi_Dispatch
 160  * and \c _glapi_Context just like the case without any threading support.
 161  * When \c _glapi_Dispatch and \c _glapi_Context are \c NULL, the thread state
 162  * data \c _gl_DispatchTSD and \c ContextTSD are used.  Drivers and the
 163  * static dispatch functions access these variables via \c _glapi_get_dispatch
 164  * and \c _glapi_get_context.
 165  *
 166  * There is a race condition in setting \c _glapi_Dispatch to \c NULL.  It is
 167  * possible for the original thread to be setting it at the same instant a new
 168  * thread, perhaps running on a different processor, is clearing it.  Because
 169  * of that, \c ThreadSafe, which can only ever be changed to \c GL_TRUE, is
 170  * used to determine whether or not the application is multithreaded.
 171  *
 172  * In the TLS case, the variables \c _glapi_Dispatch and \c _glapi_Context are
 173  * hardcoded to \c NULL.  Instead the TLS variables \c _glapi_tls_Dispatch and
 174  * \c _glapi_tls_Context are used.  Having \c _glapi_Dispatch and
 175  * \c _glapi_Context be hardcoded to \c NULL maintains binary compatability
 176  * between TLS enabled loaders and non-TLS DRI drivers.
 177  */
 178 /*@{*/
 179 #if defined(GLX_USE_TLS)
 180
 181 PUBLIC __thread struct _glapi_table * _glapi_tls_Dispatch
 182     __attribute__((tls_model("initial-exec")))
 183     = (struct _glapi_table *) __glapi_noop_table;
 184
 185 PUBLIC __thread void * _glapi_tls_Context
 186     __attribute__((tls_model("initial-exec")));
 187
 188 PUBLIC const struct _glapi_table *_glapi_Dispatch = NULL;
 189 PUBLIC const void *_glapi_Context = NULL;
 190
 191 #else
 192
 193 #if defined(THREADS)
 194
 195 static GLboolean ThreadSafe = GL_FALSE;  /**< In thread-safe mode? */
 196 _glthread_TSD _gl_DispatchTSD;           /**< Per-thread dispatch pointer */
 197 static _glthread_TSD ContextTSD;         /**< Per-thread context pointer */
 198
 199 #if defined(WIN32_THREADS)
 200 void FreeTSD(_glthread_TSD *p);
 201 void FreeAllTSD(void)
 202 {
 203    FreeTSD(&_gl_DispatchTSD);
 204    FreeTSD(&ContextTSD);
 205 }
 206 #endif /* defined(WIN32_THREADS) */
 207
 208 #endif /* defined(THREADS) */
 209
 210 PUBLIC struct _glapi_table *_glapi_Dispatch =
 211   (struct _glapi_table *) __glapi_noop_table;
 212 PUBLIC void *_glapi_Context = NULL;
 213
 214 #endif /* defined(GLX_USE_TLS) */
 215 /*@}*/
 216
 217
 218
 219
 220 /**
 221  * We should call this periodically from a function such as glXMakeCurrent
 222  * in order to test if multiple threads are being used.
 223  */
 224 void
 225 _glapi_check_multithread(void)
 226 {
 227 #if defined(THREADS) && !defined(GLX_USE_TLS)
 228    if (!ThreadSafe) {
 229       static unsigned long knownID;
 230       static GLboolean firstCall = GL_TRUE;
 231       if (firstCall) {
 232          knownID = _glthread_GetID();
 233          firstCall = GL_FALSE;
 234       }
 235       else if (knownID != _glthread_GetID()) {
 236          ThreadSafe = GL_TRUE;
 237          _glapi_set_dispatch(NULL);
 238          _glapi_set_context(NULL);
 239       }
 240    }
 241    else if (!_glapi_get_dispatch()) {
 242       /* make sure that this thread's dispatch pointer isn't null */
 243       _glapi_set_dispatch(NULL);
 244    }
 245 #endif
 246 }
 247
 248
 249
 250 /**
 251  * Set the current context pointer for this thread.
 252  * The context pointer is an opaque type which should be cast to
 253  * void from the real context pointer type.
 254  */
 255 PUBLIC void
 256 _glapi_set_context(void *context)
 257 {
 258    (void) __unused_noop_functions; /* silence a warning */
 259 #if defined(GLX_USE_TLS)
 260    _glapi_tls_Context = context;
 261 #elif defined(THREADS)
 262    _glthread_SetTSD(&ContextTSD, context);
 263    _glapi_Context = (ThreadSafe) ? NULL : context;
 264 #else
 265    _glapi_Context = context;
 266 #endif
 267 }
 268
 269
 270
 271 /**
 272  * Get the current context pointer for this thread.
 273  * The context pointer is an opaque type which should be cast from
 274  * void to the real context pointer type.
 275  */
 276 PUBLIC void *
 277 _glapi_get_context(void)
 278 {
 279 #if defined(GLX_USE_TLS)
 280    return _glapi_tls_Context;
 281 #elif defined(THREADS)
 282    if (ThreadSafe) {
 283       return _glthread_GetTSD(&ContextTSD);
 284    }
 285    else {
 286       return _glapi_Context;
 287    }
 288 #else
 289    return _glapi_Context;
 290 #endif
 291 }
 292
 293 #ifdef USE_X86_ASM
 294
 295 #if defined( GLX_USE_TLS )
 296 extern       GLubyte gl_dispatch_functions_start[];
 297 extern       GLubyte gl_dispatch_functions_end[];
 298 #else
 299 extern const GLubyte gl_dispatch_functions_start[];
 300 #endif
 301
 302 #endif /* USE_X86_ASM */
 303
 304
 305 #if defined(PTHREADS) || defined(GLX_USE_TLS)
 306 /**
 307  * Perform platform-specific GL API entry-point fixups.
 308  */
 309 static void
 310 init_glapi_relocs( void )
 311 {
 312 #if defined(USE_X86_ASM) && defined(GLX_USE_TLS) && !defined(GLX_X86_READONLY_TEXT)
 313     extern unsigned long _x86_get_dispatch(void);
 314     char run_time_patch[] = {
 315        0x65, 0xa1, 0, 0, 0, 0 /* movl %gs:0,%eax */
 316     };
 317     GLuint *offset = (GLuint *) &run_time_patch[2]; /* 32-bits for x86/32 */
 318     const GLubyte * const get_disp = (const GLubyte *) run_time_patch;
 319     GLubyte * curr_func = (GLubyte *) gl_dispatch_functions_start;
 320
 321     *offset = _x86_get_dispatch();
 322     while ( curr_func != (GLubyte *) gl_dispatch_functions_end ) {
 323         (void) memcpy( curr_func, get_disp, sizeof(run_time_patch));
 324         curr_func += DISPATCH_FUNCTION_SIZE;
 325     }
 326 #endif
 327 }
 328 #endif /* defined(PTHREADS) || defined(GLX_USE_TLS) */
 329
 330
 331 /**
 332  * Set the global or per-thread dispatch table pointer.
 333  * If the dispatch parameter is NULL we'll plug in the no-op dispatch
 334  * table (__glapi_noop_table).
 335  */
 336 PUBLIC void
 337 _glapi_set_dispatch(struct _glapi_table *dispatch)
 338 {
 339 #if defined(PTHREADS) || defined(GLX_USE_TLS)
 340    static pthread_once_t once_control = PTHREAD_ONCE_INIT;
 341    pthread_once( & once_control, init_glapi_relocs );
 342 #endif
 343
 344    if (!dispatch) {
 345       /* use the no-op functions */
 346       dispatch = (struct _glapi_table *) __glapi_noop_table;
 347    }
 348 #ifdef DEBUG
 349    else {
 350       _glapi_check_table(dispatch);
 351    }
 352 #endif
 353
 354 #if defined(GLX_USE_TLS)
 355    _glapi_tls_Dispatch = dispatch;
 356 #elif defined(THREADS)
 357    _glthread_SetTSD(&_gl_DispatchTSD, (void *) dispatch);
 358    _glapi_Dispatch = (ThreadSafe) ? NULL : dispatch;
 359 #else /*THREADS*/
 360    _glapi_Dispatch = dispatch;
 361 #endif /*THREADS*/
 362 }
 363
 364
 365
 366 /**
 367  * Return pointer to current dispatch table for calling thread.
 368  */
 369 PUBLIC struct _glapi_table *
 370 _glapi_get_dispatch(void)
 371 {
 372    struct _glapi_table * api;
 373 #if defined(GLX_USE_TLS)
 374    api = _glapi_tls_Dispatch;
 375 #elif defined(THREADS)
 376    api = (ThreadSafe)
 377      ? (struct _glapi_table *) _glthread_GetTSD(&_gl_DispatchTSD)
 378      : _glapi_Dispatch;
 379 #else
 380    api = _glapi_Dispatch;
 381 #endif
 382    return api;
 383 }
 384
 385
 386
 387
 388 /*
 389  * The dispatch table size (number of entries) is the size of the
 390  * _glapi_table struct plus the number of dynamic entries we can add.
 391  * The extra slots can be filled in by DRI drivers that register new extension
 392  * functions.
 393  */
 394 #define DISPATCH_TABLE_SIZE (sizeof(struct _glapi_table) / sizeof(void *) + MAX_EXTENSION_FUNCS)
 395
 396
 397 /**
 398  * Return size of dispatch table struct as number of functions (or
 399  * slots).
 400  */
 401 PUBLIC GLuint
 402 _glapi_get_dispatch_table_size(void)
 403 {
 404    return DISPATCH_TABLE_SIZE;
 405 }
 406
 407
 408 /**
 409  * Make sure there are no NULL pointers in the given dispatch table.
 410  * Intended for debugging purposes.
 411  */
 412 void
 413 _glapi_check_table(const struct _glapi_table *table)
 414 {
 415 #ifdef EXTRA_DEBUG
 416    const GLuint entries = _glapi_get_dispatch_table_size();
 417    const void **tab = (const void **) table;
 418    GLuint i;
 419    for (i = 1; i < entries; i++) {
 420       assert(tab[i]);
 421    }
 422
 423    /* Do some spot checks to be sure that the dispatch table
 424     * slots are assigned correctly.
 425     */
 426    {
 427       GLuint BeginOffset = _glapi_get_proc_offset("glBegin");
 428       char *BeginFunc = (char*) &table->Begin;
 429       GLuint offset = (BeginFunc - (char *) table) / sizeof(void *);
 430       assert(BeginOffset == _gloffset_Begin);
 431       assert(BeginOffset == offset);
 432    }
 433    {
 434       GLuint viewportOffset = _glapi_get_proc_offset("glViewport");
 435       char *viewportFunc = (char*) &table->Viewport;
 436       GLuint offset = (viewportFunc - (char *) table) / sizeof(void *);
 437       assert(viewportOffset == _gloffset_Viewport);
 438       assert(viewportOffset == offset);
 439    }
 440    {
 441       GLuint VertexPointerOffset = _glapi_get_proc_offset("glVertexPointer");
 442       char *VertexPointerFunc = (char*) &table->VertexPointer;
 443       GLuint offset = (VertexPointerFunc - (char *) table) / sizeof(void *);
 444       assert(VertexPointerOffset == _gloffset_VertexPointer);
 445       assert(VertexPointerOffset == offset);
 446    }
 447    {
 448       GLuint ResetMinMaxOffset = _glapi_get_proc_offset("glResetMinmax");
 449       char *ResetMinMaxFunc = (char*) &table->ResetMinmax;
 450       GLuint offset = (ResetMinMaxFunc - (char *) table) / sizeof(void *);
 451       assert(ResetMinMaxOffset == _gloffset_ResetMinmax);
 452       assert(ResetMinMaxOffset == offset);
 453    }
 454    {
 455       GLuint blendColorOffset = _glapi_get_proc_offset("glBlendColor");
 456       char *blendColorFunc = (char*) &table->BlendColor;
 457       GLuint offset = (blendColorFunc - (char *) table) / sizeof(void *);
 458       assert(blendColorOffset == _gloffset_BlendColor);
 459       assert(blendColorOffset == offset);
 460    }
 461    {
 462       GLuint secondaryColor3fOffset = _glapi_get_proc_offset("glSecondaryColor3fEXT");
 463       char *secondaryColor3fFunc = (char*) &table->SecondaryColor3fEXT;
 464       GLuint offset = (secondaryColor3fFunc - (char *) table) / sizeof(void *);
 465       assert(secondaryColor3fOffset == _gloffset_SecondaryColor3fEXT);
 466       assert(secondaryColor3fOffset == offset);
 467    }
 468    {
 469       GLuint pointParameterivOffset = _glapi_get_proc_offset("glPointParameterivNV");
 470       char *pointParameterivFunc = (char*) &table->PointParameterivNV;
 471       GLuint offset = (pointParameterivFunc - (char *) table) / sizeof(void *);
 472       assert(pointParameterivOffset == _gloffset_PointParameterivNV);
 473       assert(pointParameterivOffset == offset);
 474    }
 475    {
 476       GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
 477       char *setFenceFunc = (char*) &table->SetFenceNV;
 478       GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
 479       assert(setFenceOffset == _gloffset_SetFenceNV);
 480       assert(setFenceOffset == offset);
 481    }
 482 #else
 483    (void) table;
 484 #endif
 485 }