src/mesa/glapi/glapi.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5
   4  *
   5  * Copyright (C) 1999-2006  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 #include "glheader.h"
  54 #include "glapi.h"
  55 #include "glapioffsets.h"
  56 #include "glapitable.h"
  57
  58 /***** BEGIN NO-OP DISPATCH *****/
  59
  60 static GLboolean WarnFlag = GL_FALSE;
  61 static _glapi_warning_func warning_func;
  62
  63 #if defined(PTHREADS) || defined(GLX_USE_TLS)
  64 static void init_glapi_relocs(void);
  65 #endif
  66
  67 static _glapi_proc generate_entrypoint(GLuint functionOffset);
  68 static void fill_in_entrypoint_offset(_glapi_proc entrypoint, GLuint offset);
  69
  70 /*
  71  * Enable/disable printing of warning messages.
  72  */
  73 PUBLIC void
  74 _glapi_noop_enable_warnings(GLboolean enable)
  75 {
  76    WarnFlag = enable;
  77 }
  78
  79 /*
  80  * Register a callback function for reporting errors.
  81  */
  82 PUBLIC void
  83 _glapi_set_warning_func( _glapi_warning_func func )
  84 {
  85    warning_func = func;
  86 }
  87
  88 static GLboolean
  89 warn(void)
  90 {
  91    if ((WarnFlag || getenv("MESA_DEBUG") || getenv("LIBGL_DEBUG"))
  92        && warning_func) {
  93       return GL_TRUE;
  94    }
  95    else {
  96       return GL_FALSE;
  97    }
  98 }
  99
 100
 101 #define KEYWORD1 static
 102 #define KEYWORD2 GLAPIENTRY
 103 #define NAME(func)  NoOp##func
 104
 105 #define F NULL
 106
 107 #define DISPATCH(func, args, msg)                                             \
 108    if (warn()) {                                                              \
 109       warning_func(NULL, "GL User Error: called without context: %s", #func); \
 110    }
 111
 112 #define RETURN_DISPATCH(func, args, msg)                                      \
 113    if (warn()) {                                                              \
 114       warning_func(NULL, "GL User Error: called without context: %s", #func); \
 115    }                                                                          \
 116    return 0
 117
 118 #define DISPATCH_TABLE_NAME __glapi_noop_table
 119 #define UNUSED_TABLE_NAME __unused_noop_functions
 120
 121 #define TABLE_ENTRY(name) (_glapi_proc) NoOp##name
 122
 123 static GLint NoOpUnused(void)
 124 {
 125    if (warn()) {
 126       warning_func(NULL, "GL User Error: calling extension function without a current context\n");
 127    }
 128    return 0;
 129 }
 130
 131 #include "glapitemp.h"
 132
 133 /***** END NO-OP DISPATCH *****/
 134
 135
 136
 137 /**
 138  * \name Current dispatch and current context control variables
 139  *
 140  * Depending on whether or not multithreading is support, and the type of
 141  * support available, several variables are used to store the current context
 142  * pointer and the current dispatch table pointer.  In the non-threaded case,
 143  * the variables \c _glapi_Dispatch and \c _glapi_Context are used for this
 144  * purpose.
 145  *
 146  * In the "normal" threaded case, the variables \c _glapi_Dispatch and
 147  * \c _glapi_Context will be \c NULL if an application is detected as being
 148  * multithreaded.  Single-threaded applications will use \c _glapi_Dispatch
 149  * and \c _glapi_Context just like the case without any threading support.
 150  * When \c _glapi_Dispatch and \c _glapi_Context are \c NULL, the thread state
 151  * data \c _gl_DispatchTSD and \c ContextTSD are used.  Drivers and the
 152  * static dispatch functions access these variables via \c _glapi_get_dispatch
 153  * and \c _glapi_get_context.
 154  *
 155  * There is a race condition in setting \c _glapi_Dispatch to \c NULL.  It is
 156  * possible for the original thread to be setting it at the same instant a new
 157  * thread, perhaps running on a different processor, is clearing it.  Because
 158  * of that, \c ThreadSafe, which can only ever be changed to \c GL_TRUE, is
 159  * used to determine whether or not the application is multithreaded.
 160  *
 161  * In the TLS case, the variables \c _glapi_Dispatch and \c _glapi_Context are
 162  * hardcoded to \c NULL.  Instead the TLS variables \c _glapi_tls_Dispatch and
 163  * \c _glapi_tls_Context are used.  Having \c _glapi_Dispatch and
 164  * \c _glapi_Context be hardcoded to \c NULL maintains binary compatability
 165  * between TLS enabled loaders and non-TLS DRI drivers.
 166  */
 167 /*@{*/
 168 #if defined(GLX_USE_TLS)
 169
 170 PUBLIC __thread struct _glapi_table * _glapi_tls_Dispatch
 171     __attribute__((tls_model("initial-exec")))
 172     = (struct _glapi_table *) __glapi_noop_table;
 173
 174 PUBLIC __thread void * _glapi_tls_Context
 175     __attribute__((tls_model("initial-exec")));
 176
 177 PUBLIC const struct _glapi_table *_glapi_Dispatch = NULL;
 178 PUBLIC const void *_glapi_Context = NULL;
 179
 180 #else
 181
 182 #if defined(THREADS)
 183
 184 static GLboolean ThreadSafe = GL_FALSE;  /**< In thread-safe mode? */
 185 _glthread_TSD _gl_DispatchTSD;           /**< Per-thread dispatch pointer */
 186 static _glthread_TSD ContextTSD;         /**< Per-thread context pointer */
 187
 188 #endif /* defined(THREADS) */
 189
 190 PUBLIC struct _glapi_table *_glapi_Dispatch =
 191   (struct _glapi_table *) __glapi_noop_table;
 192 PUBLIC void *_glapi_Context = NULL;
 193
 194 #endif /* defined(GLX_USE_TLS) */
 195 /*@}*/
 196
 197
 198 /**
 199  * strdup() is actually not a standard ANSI C or POSIX routine.
 200  * Irix will not define it if ANSI mode is in effect.
 201  */
 202 static char *
 203 str_dup(const char *str)
 204 {
 205    char *copy;
 206    copy = (char*) malloc(strlen(str) + 1);
 207    if (!copy)
 208       return NULL;
 209    strcpy(copy, str);
 210    return copy;
 211 }
 212
 213
 214
 215 /**
 216  * We should call this periodically from a function such as glXMakeCurrent
 217  * in order to test if multiple threads are being used.
 218  */
 219 void
 220 _glapi_check_multithread(void)
 221 {
 222 #if defined(THREADS) && !defined(GLX_USE_TLS)
 223    if (!ThreadSafe) {
 224       static unsigned long knownID;
 225       static GLboolean firstCall = GL_TRUE;
 226       if (firstCall) {
 227          knownID = _glthread_GetID();
 228          firstCall = GL_FALSE;
 229       }
 230       else if (knownID != _glthread_GetID()) {
 231          ThreadSafe = GL_TRUE;
 232          _glapi_set_dispatch(NULL);
 233       }
 234    }
 235    else if (!_glapi_get_dispatch()) {
 236       /* make sure that this thread's dispatch pointer isn't null */
 237       _glapi_set_dispatch(NULL);
 238    }
 239 #endif
 240 }
 241
 242
 243
 244 /**
 245  * Set the current context pointer for this thread.
 246  * The context pointer is an opaque type which should be cast to
 247  * void from the real context pointer type.
 248  */
 249 PUBLIC void
 250 _glapi_set_context(void *context)
 251 {
 252    (void) __unused_noop_functions; /* silence a warning */
 253 #if defined(GLX_USE_TLS)
 254    _glapi_tls_Context = context;
 255 #elif defined(THREADS)
 256    _glthread_SetTSD(&ContextTSD, context);
 257    _glapi_Context = (ThreadSafe) ? NULL : context;
 258 #else
 259    _glapi_Context = context;
 260 #endif
 261 }
 262
 263
 264
 265 /**
 266  * Get the current context pointer for this thread.
 267  * The context pointer is an opaque type which should be cast from
 268  * void to the real context pointer type.
 269  */
 270 PUBLIC void *
 271 _glapi_get_context(void)
 272 {
 273 #if defined(GLX_USE_TLS)
 274    return _glapi_tls_Context;
 275 #elif defined(THREADS)
 276    if (ThreadSafe) {
 277       return _glthread_GetTSD(&ContextTSD);
 278    }
 279    else {
 280       return _glapi_Context;
 281    }
 282 #else
 283    return _glapi_Context;
 284 #endif
 285 }
 286
 287
 288
 289 /**
 290  * Set the global or per-thread dispatch table pointer.
 291  * If the dispatch parameter is NULL we'll plug in the no-op dispatch
 292  * table (__glapi_noop_table).
 293  */
 294 PUBLIC void
 295 _glapi_set_dispatch(struct _glapi_table *dispatch)
 296 {
 297 #if defined(PTHREADS) || defined(GLX_USE_TLS)
 298    static pthread_once_t once_control = PTHREAD_ONCE_INIT;
 299    pthread_once( & once_control, init_glapi_relocs );
 300 #endif
 301
 302    if (!dispatch) {
 303       /* use the no-op functions */
 304       dispatch = (struct _glapi_table *) __glapi_noop_table;
 305    }
 306 #ifdef DEBUG
 307    else {
 308       _glapi_check_table(dispatch);
 309    }
 310 #endif
 311
 312 #if defined(GLX_USE_TLS)
 313    _glapi_tls_Dispatch = dispatch;
 314 #elif defined(THREADS)
 315    _glthread_SetTSD(&_gl_DispatchTSD, (void *) dispatch);
 316    _glapi_Dispatch = (ThreadSafe) ? NULL : dispatch;
 317 #else /*THREADS*/
 318    _glapi_Dispatch = dispatch;
 319 #endif /*THREADS*/
 320 }
 321
 322
 323
 324 /**
 325  * Return pointer to current dispatch table for calling thread.
 326  */
 327 PUBLIC struct _glapi_table *
 328 _glapi_get_dispatch(void)
 329 {
 330    struct _glapi_table * api;
 331 #if defined(GLX_USE_TLS)
 332    api = _glapi_tls_Dispatch;
 333 #elif defined(THREADS)
 334    api = (ThreadSafe)
 335      ? (struct _glapi_table *) _glthread_GetTSD(&_gl_DispatchTSD)
 336      : _glapi_Dispatch;
 337 #else
 338    api = _glapi_Dispatch;
 339 #endif
 340    return api;
 341 }
 342
 343
 344
 345 /***
 346  *** The rest of this file is pretty much concerned with GetProcAddress
 347  *** functionality.
 348  ***/
 349
 350 #if !defined( USE_X86_ASM ) && !defined( XFree86Server ) && !defined ( XGLServer )
 351 #define NEED_FUNCTION_POINTER
 352 #endif
 353
 354 /* The code in this file is auto-generated with Python */
 355 #include "glprocs.h"
 356
 357
 358 /**
 359  * Search the table of static entrypoint functions for the named function
 360  * and return the corresponding glprocs_table_t entry.
 361  */
 362 static const glprocs_table_t *
 363 find_entry( const char * n )
 364 {
 365    GLuint i;
 366    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
 367       const char *testName = gl_string_table + static_functions[i].Name_offset;
 368       if (strcmp(testName, n) == 0) {
 369          return &static_functions[i];
 370       }
 371    }
 372    return NULL;
 373 }
 374
 375
 376 /**
 377  * Return dispatch table offset of the named static (built-in) function.
 378  * Return -1 if function not found.
 379  */
 380 static GLint
 381 get_static_proc_offset(const char *funcName)
 382 {
 383    const glprocs_table_t * const f = find_entry( funcName );
 384    if (f) {
 385       return f->Offset;
 386    }
 387    return -1;
 388 }
 389
 390
 391 #if !defined(XFree86Server) && !defined(XGLServer)
 392 #ifdef USE_X86_ASM
 393
 394 #if defined( GLX_USE_TLS )
 395 extern       GLubyte gl_dispatch_functions_start[];
 396 extern       GLubyte gl_dispatch_functions_end[];
 397 #else
 398 extern const GLubyte gl_dispatch_functions_start[];
 399 #endif
 400
 401 # if defined(THREADS) && !defined(GLX_USE_TLS)
 402 #  define X86_DISPATCH_FUNCTION_SIZE  32
 403 # else
 404 #  define X86_DISPATCH_FUNCTION_SIZE  16
 405 # endif
 406
 407 #endif /* USE_X86_ASM */
 408
 409
 410 /**
 411  * Return dispatch function address for the named static (built-in) function.
 412  * Return NULL if function not found.
 413  */
 414 static const _glapi_proc
 415 get_static_proc_address(const char *funcName)
 416 {
 417    const glprocs_table_t * const f = find_entry( funcName );
 418    if (f) {
 419 #ifdef USE_X86_ASM
 420       return (_glapi_proc) (gl_dispatch_functions_start
 421                             + (X86_DISPATCH_FUNCTION_SIZE * f->Offset));
 422 #else
 423       return f->Address;
 424 #endif
 425    }
 426    else {
 427       return NULL;
 428    }
 429 }
 430
 431 #endif /* !defined(XFree86Server) && !defined(XGLServer) */
 432
 433
 434
 435 /**
 436  * Return the name of the function at the given offset in the dispatch
 437  * table.  For debugging only.
 438  */
 439 static const char *
 440 get_static_proc_name( GLuint offset )
 441 {
 442    GLuint i;
 443    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
 444       if (static_functions[i].Offset == offset) {
 445          return gl_string_table + static_functions[i].Name_offset;
 446       }
 447    }
 448    return NULL;
 449 }
 450
 451
 452
 453 /**********************************************************************
 454  * Extension function management.
 455  */
 456
 457 /*
 458  * Number of extension functions which we can dynamically add at runtime.
 459  */
 460 #define MAX_EXTENSION_FUNCS 300
 461
 462
 463 /*
 464  * The dispatch table size (number of entries) is the size of the
 465  * _glapi_table struct plus the number of dynamic entries we can add.
 466  * The extra slots can be filled in by DRI drivers that register new extension
 467  * functions.
 468  */
 469 #define DISPATCH_TABLE_SIZE (sizeof(struct _glapi_table) / sizeof(void *) + MAX_EXTENSION_FUNCS)
 470
 471
 472 /**
 473  * Track information about a function added to the GL API.
 474  */
 475 struct _glapi_function {
 476    /**
 477     * Name of the function.
 478     */
 479    const char * name;
 480
 481
 482    /**
 483     * Text string that describes the types of the parameters passed to the
 484     * named function.   Parameter types are converted to characters using the
 485     * following rules:
 486     *   - 'i' for \c GLint, \c GLuint, and \c GLenum
 487     *   - 'p' for any pointer type
 488     *   - 'f' for \c GLfloat and \c GLclampf
 489     *   - 'd' for \c GLdouble and \c GLclampd
 490     */
 491    const char * parameter_signature;
 492
 493
 494    /**
 495     * Offset in the dispatch table where the pointer to the real function is
 496     * located.  If the driver has not requested that the named function be
 497     * added to the dispatch table, this will have the value ~0.
 498     */
 499    unsigned dispatch_offset;
 500
 501
 502    /**
 503     * Pointer to the dispatch stub for the named function.
 504     *
 505     * \todo
 506     * The semantic of this field should be changed slightly.  Currently, it
 507     * is always expected to be non-\c NULL.  However, it would be better to
 508     * only allocate the entry-point stub when the application requests the
 509     * function via \c glXGetProcAddress.  This would save memory for all the
 510     * functions that the driver exports but that the application never wants
 511     * to call.
 512     */
 513    _glapi_proc dispatch_stub;
 514 };
 515
 516
 517 static struct _glapi_function ExtEntryTable[MAX_EXTENSION_FUNCS];
 518 static GLuint NumExtEntryPoints = 0;
 519
 520 #ifdef USE_SPARC_ASM
 521 extern void __glapi_sparc_icache_flush(unsigned int *);
 522 #endif
 523
 524 /**
 525  * Generate a dispatch function (entrypoint) which jumps through
 526  * the given slot number (offset) in the current dispatch table.
 527  * We need assembly language in order to accomplish this.
 528  */
 529 static _glapi_proc
 530 generate_entrypoint(GLuint functionOffset)
 531 {
 532 #if defined(USE_X86_ASM)
 533    /* 32 is chosen as something of a magic offset.  For x86, the dispatch
 534     * at offset 32 is the first one where the offset in the
 535     * "jmp OFFSET*4(%eax)" can't be encoded in a single byte.
 536     */
 537    const GLubyte * const template_func = gl_dispatch_functions_start
 538      + (X86_DISPATCH_FUNCTION_SIZE * 32);
 539    GLubyte * const code = (GLubyte *) malloc( X86_DISPATCH_FUNCTION_SIZE );
 540
 541
 542    if ( code != NULL ) {
 543       (void) memcpy( code, template_func, X86_DISPATCH_FUNCTION_SIZE );
 544       fill_in_entrypoint_offset( (_glapi_proc) code, functionOffset );
 545    }
 546
 547    return (_glapi_proc) code;
 548 #elif defined(USE_SPARC_ASM)
 549
 550 #ifdef __arch64__
 551    static const unsigned int insn_template[] = {
 552            0x05000000,  /* sethi        %uhi(_glapi_Dispatch), %g2      */
 553            0x03000000,  /* sethi        %hi(_glapi_Dispatch), %g1       */
 554            0x8410a000,  /* or           %g2, %ulo(_glapi_Dispatch), %g2 */
 555            0x82106000,  /* or           %g1, %lo(_glapi_Dispatch), %g1  */
 556            0x8528b020,  /* sllx         %g2, 32, %g2                    */
 557            0xc2584002,  /* ldx          [%g1 + %g2], %g1                */
 558            0x05000000,  /* sethi        %hi(8 * glapioffset), %g2       */
 559            0x8410a000,  /* or           %g2, %lo(8 * glapioffset), %g2  */
 560            0xc6584002,  /* ldx          [%g1 + %g2], %g3                */
 561            0x81c0c000,  /* jmpl         %g3, %g0                        */
 562            0x01000000   /*  nop                                         */
 563    };
 564 #else
 565    static const unsigned int insn_template[] = {
 566            0x03000000,  /* sethi        %hi(_glapi_Dispatch), %g1         */
 567            0xc2006000,  /* ld           [%g1 + %lo(_glapi_Dispatch)], %g1 */
 568            0xc6006000,  /* ld           [%g1 + %lo(4*glapioffset)], %g3   */
 569            0x81c0c000,  /* jmpl         %g3, %g0                          */
 570            0x01000000   /*  nop                                           */
 571    };
 572 #endif /* __arch64__ */
 573    unsigned int *code = (unsigned int *) malloc(sizeof(insn_template));
 574    unsigned long glapi_addr = (unsigned long) &_glapi_Dispatch;
 575    if (code) {
 576       memcpy(code, insn_template, sizeof(insn_template));
 577
 578 #ifdef __arch64__
 579       code[0] |= (glapi_addr >> (32 + 10));
 580       code[1] |= ((glapi_addr & 0xffffffff) >> 10);
 581       __glapi_sparc_icache_flush(&code[0]);
 582       code[2] |= ((glapi_addr >> 32) & ((1 << 10) - 1));
 583       code[3] |= (glapi_addr & ((1 << 10) - 1));
 584       __glapi_sparc_icache_flush(&code[2]);
 585       code[6] |= ((functionOffset * 8) >> 10);
 586       code[7] |= ((functionOffset * 8) & ((1 << 10) - 1));
 587       __glapi_sparc_icache_flush(&code[6]);
 588 #else
 589       code[0] |= (glapi_addr >> 10);
 590       code[1] |= (glapi_addr & ((1 << 10) - 1));
 591       __glapi_sparc_icache_flush(&code[0]);
 592       code[2] |= (functionOffset * 4);
 593       __glapi_sparc_icache_flush(&code[2]);
 594 #endif /* __arch64__ */
 595    }
 596    return (_glapi_proc) code;
 597 #else
 598    (void) functionOffset;
 599    return NULL;
 600 #endif /* USE_*_ASM */
 601 }
 602
 603
 604 /**
 605  * This function inserts a new dispatch offset into the assembly language
 606  * stub that was generated with the preceeding function.
 607  */
 608 static void
 609 fill_in_entrypoint_offset(_glapi_proc entrypoint, GLuint offset)
 610 {
 611 #if defined(USE_X86_ASM)
 612    GLubyte * const code = (GLubyte *) entrypoint;
 613
 614 #if X86_DISPATCH_FUNCTION_SIZE == 32
 615    *((unsigned int *)(code + 11)) = 4 * offset;
 616    *((unsigned int *)(code + 22)) = 4 * offset;
 617 #elif X86_DISPATCH_FUNCTION_SIZE == 16 && defined( GLX_USE_TLS )
 618    *((unsigned int *)(code +  8)) = 4 * offset;
 619 #elif X86_DISPATCH_FUNCTION_SIZE == 16
 620    *((unsigned int *)(code +  7)) = 4 * offset;
 621 #else
 622 # error Invalid X86_DISPATCH_FUNCTION_SIZE!
 623 #endif
 624
 625 #elif defined(USE_SPARC_ASM)
 626
 627    /* XXX this hasn't been tested! */
 628    unsigned int *code = (unsigned int *) entrypoint;
 629 #ifdef __arch64__
 630    code[6] = 0x05000000;  /* sethi      %hi(8 * glapioffset), %g2       */
 631    code[7] = 0x8410a000;  /* or         %g2, %lo(8 * glapioffset), %g2  */
 632    code[6] |= ((offset * 8) >> 10);
 633    code[7] |= ((offset * 8) & ((1 << 10) - 1));
 634    __glapi_sparc_icache_flush(&code[6]);
 635 #else /* __arch64__ */
 636    code[2] = 0xc6006000;  /* ld         [%g1 + %lo(4*glapioffset)], %g3   */
 637    code[2] |= (offset * 4);
 638    __glapi_sparc_icache_flush(&code[2]);
 639 #endif /* __arch64__ */
 640
 641 #else
 642
 643    /* an unimplemented architecture */
 644    (void) entrypoint;
 645    (void) offset;
 646
 647 #endif /* USE_*_ASM */
 648 }
 649
 650
 651 /**
 652  * Generate new entrypoint
 653  *
 654  * Use a temporary dispatch offset of ~0 (i.e. -1).  Later, when the driver
 655  * calls \c _glapi_add_dispatch we'll put in the proper offset.  If that
 656  * never happens, and the user calls this function, he'll segfault.  That's
 657  * what you get when you try calling a GL function that doesn't really exist.
 658  *
 659  * \param funcName  Name of the function to create an entry-point for.
 660  *
 661  * \sa _glapi_add_entrypoint
 662  */
 663
 664 static struct _glapi_function *
 665 add_function_name( const char * funcName )
 666 {
 667    struct _glapi_function * entry = NULL;
 668
 669    if (NumExtEntryPoints < MAX_EXTENSION_FUNCS) {
 670       _glapi_proc entrypoint = generate_entrypoint(~0);
 671       if (entrypoint != NULL) {
 672          entry = & ExtEntryTable[NumExtEntryPoints];
 673
 674          ExtEntryTable[NumExtEntryPoints].name = str_dup(funcName);
 675          ExtEntryTable[NumExtEntryPoints].parameter_signature = NULL;
 676          ExtEntryTable[NumExtEntryPoints].dispatch_offset = ~0;
 677          ExtEntryTable[NumExtEntryPoints].dispatch_stub = entrypoint;
 678          NumExtEntryPoints++;
 679       }
 680    }
 681
 682    return entry;
 683 }
 684
 685
 686 /**
 687  * Fill-in the dispatch stub for the named function.
 688  *
 689  * This function is intended to be called by a hardware driver.  When called,
 690  * a dispatch stub may be created created for the function.  A pointer to this
 691  * dispatch function will be returned by glXGetProcAddress.
 692  *
 693  * \param function_names       Array of pointers to function names that should
 694  *                             share a common dispatch offset.
 695  * \param parameter_signature  String representing the types of the parameters
 696  *                             passed to the named function.  Parameter types
 697  *                             are converted to characters using the following
 698  *                             rules:
 699  *                               - 'i' for \c GLint, \c GLuint, and \c GLenum
 700  *                               - 'p' for any pointer type
 701  *                               - 'f' for \c GLfloat and \c GLclampf
 702  *                               - 'd' for \c GLdouble and \c GLclampd
 703  *
 704  * \returns
 705  * The offset in the dispatch table of the named function.  A pointer to the
 706  * driver's implementation of the named function should be stored at
 707  * \c dispatch_table[\c offset].
 708  *
 709  * \sa glXGetProcAddress
 710  *
 711  * \warning
 712  * This function can only handle up to 8 names at a time.  As far as I know,
 713  * the maximum number of names ever associated with an existing GL function is
 714  * 4 (\c glPointParameterfSGIS, \c glPointParameterfEXT,
 715  * \c glPointParameterfARB, and \c glPointParameterf), so this should not be
 716  * too painful of a limitation.
 717  *
 718  * \todo
 719  * Determine whether or not \c parameter_signature should be allowed to be
 720  * \c NULL.  It doesn't seem like much of a hardship for drivers to have to
 721  * pass in an empty string.
 722  *
 723  * \todo
 724  * Determine if code should be added to reject function names that start with
 725  * 'glX'.
 726  *
 727  * \bug
 728  * Add code to compare \c parameter_signature with the parameter signature of
 729  * a static function.  In order to do that, we need to find a way to \b get
 730  * the parameter signature of a static function.
 731  */
 732
 733 PUBLIC int
 734 _glapi_add_dispatch( const char * const * function_names,
 735                      const char * parameter_signature )
 736 {
 737    static int next_dynamic_offset = _gloffset_FIRST_DYNAMIC;
 738    const char * const real_sig = (parameter_signature != NULL)
 739      ? parameter_signature : "";
 740    struct _glapi_function * entry[8];
 741    GLboolean is_static[8];
 742    unsigned i;
 743    unsigned j;
 744    int offset = ~0;
 745    int new_offset;
 746
 747
 748    (void) memset( is_static, 0, sizeof( is_static ) );
 749    (void) memset( entry, 0, sizeof( entry ) );
 750
 751    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 752       /* Do some trivial validation on the name of the function.
 753        */
 754
 755       if (!function_names[i] || function_names[i][0] != 'g' || function_names[i][1] != 'l')
 756         return GL_FALSE;
 757
 758       /* Determine if the named function already exists.  If the function does
 759        * exist, it must have the same parameter signature as the function
 760        * being added.
 761        */
 762
 763       new_offset = get_static_proc_offset(function_names[i]);
 764       if (new_offset >= 0) {
 765          /* FIXME: Make sure the parameter signatures match!  How do we get
 766           * FIXME: the parameter signature for static functions?
 767           */
 768
 769          if ( (offset != ~0) && (new_offset != offset) ) {
 770             return -1;
 771          }
 772
 773          is_static[i] = GL_TRUE;
 774          offset = new_offset;
 775       }
 776
 777
 778       for ( j = 0 ; j < NumExtEntryPoints ; j++ ) {
 779          if (strcmp(ExtEntryTable[j].name, function_names[i]) == 0) {
 780             /* The offset may be ~0 if the function name was added by
 781              * glXGetProcAddress but never filled in by the driver.
 782              */
 783
 784             if (ExtEntryTable[j].dispatch_offset != ~0) {
 785                if (strcmp(real_sig, ExtEntryTable[j].parameter_signature)
 786                    != 0) {
 787                   return -1;
 788                }
 789
 790                if ( (offset != ~0) && (ExtEntryTable[j].dispatch_offset != offset) ) {
 791                   return -1;
 792                }
 793
 794                offset = ExtEntryTable[j].dispatch_offset;
 795             }
 796
 797             entry[i] = & ExtEntryTable[j];
 798             break;
 799          }
 800       }
 801    }
 802
 803    if (offset == ~0) {
 804       offset = next_dynamic_offset;
 805       next_dynamic_offset++;
 806    }
 807
 808    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 809       if (! is_static[i] ) {
 810          if (entry[i] == NULL) {
 811             entry[i] = add_function_name( function_names[i] );
 812             if (entry[i] == NULL) {
 813                /* FIXME: Possible memory leak here.
 814                 */
 815                return -1;
 816             }
 817          }
 818
 819          entry[i]->parameter_signature = str_dup(real_sig);
 820          fill_in_entrypoint_offset(entry[i]->dispatch_stub, offset);
 821          entry[i]->dispatch_offset = offset;
 822       }
 823    }
 824
 825    return offset;
 826 }
 827
 828
 829 /**
 830  * Return offset of entrypoint for named function within dispatch table.
 831  */
 832 PUBLIC GLint
 833 _glapi_get_proc_offset(const char *funcName)
 834 {
 835    /* search extension functions first */
 836    GLuint i;
 837    for (i = 0; i < NumExtEntryPoints; i++) {
 838       if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
 839          return ExtEntryTable[i].dispatch_offset;
 840       }
 841    }
 842    /* search static functions */
 843    return get_static_proc_offset(funcName);
 844 }
 845
 846
 847
 848 /**
 849  * Return pointer to the named function.  If the function name isn't found
 850  * in the name of static functions, try generating a new API entrypoint on
 851  * the fly with assembly language.
 852  */
 853 _glapi_proc
 854 _glapi_get_proc_address(const char *funcName)
 855 {
 856    struct _glapi_function * entry;
 857    GLuint i;
 858
 859 #ifdef MANGLE
 860    if (funcName[0] != 'm' || funcName[1] != 'g' || funcName[2] != 'l')
 861       return NULL;
 862 #else
 863    if (funcName[0] != 'g' || funcName[1] != 'l')
 864       return NULL;
 865 #endif
 866
 867    /* search extension functions first */
 868    for (i = 0; i < NumExtEntryPoints; i++) {
 869       if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
 870          return ExtEntryTable[i].dispatch_stub;
 871       }
 872    }
 873
 874 #if !defined( XFree86Server ) && !defined( XGLServer )
 875    /* search static functions */
 876    {
 877       const _glapi_proc func = get_static_proc_address(funcName);
 878       if (func)
 879          return func;
 880    }
 881 #endif /* !defined( XFree86Server ) */
 882
 883    entry = add_function_name(funcName);
 884    return (entry == NULL) ? NULL : entry->dispatch_stub;
 885 }
 886
 887
 888
 889 /**
 890  * Return the name of the function at the given dispatch offset.
 891  * This is only intended for debugging.
 892  */
 893 const char *
 894 _glapi_get_proc_name(GLuint offset)
 895 {
 896    GLuint i;
 897    const char * n;
 898
 899    /* search built-in functions */
 900    n = get_static_proc_name(offset);
 901    if ( n != NULL ) {
 902       return n;
 903    }
 904
 905    /* search added extension functions */
 906    for (i = 0; i < NumExtEntryPoints; i++) {
 907       if (ExtEntryTable[i].dispatch_offset == offset) {
 908          return ExtEntryTable[i].name;
 909       }
 910    }
 911    return NULL;
 912 }
 913
 914
 915
 916 /**
 917  * Return size of dispatch table struct as number of functions (or
 918  * slots).
 919  */
 920 PUBLIC GLuint
 921 _glapi_get_dispatch_table_size(void)
 922 {
 923    return DISPATCH_TABLE_SIZE;
 924 }
 925
 926
 927
 928 /**
 929  * Make sure there are no NULL pointers in the given dispatch table.
 930  * Intended for debugging purposes.
 931  */
 932 void
 933 _glapi_check_table(const struct _glapi_table *table)
 934 {
 935 #ifdef DEBUG
 936    const GLuint entries = _glapi_get_dispatch_table_size();
 937    const void **tab = (const void **) table;
 938    GLuint i;
 939    for (i = 1; i < entries; i++) {
 940       assert(tab[i]);
 941    }
 942
 943    /* Do some spot checks to be sure that the dispatch table
 944     * slots are assigned correctly.
 945     */
 946    {
 947       GLuint BeginOffset = _glapi_get_proc_offset("glBegin");
 948       char *BeginFunc = (char*) &table->Begin;
 949       GLuint offset = (BeginFunc - (char *) table) / sizeof(void *);
 950       assert(BeginOffset == _gloffset_Begin);
 951       assert(BeginOffset == offset);
 952    }
 953    {
 954       GLuint viewportOffset = _glapi_get_proc_offset("glViewport");
 955       char *viewportFunc = (char*) &table->Viewport;
 956       GLuint offset = (viewportFunc - (char *) table) / sizeof(void *);
 957       assert(viewportOffset == _gloffset_Viewport);
 958       assert(viewportOffset == offset);
 959    }
 960    {
 961       GLuint VertexPointerOffset = _glapi_get_proc_offset("glVertexPointer");
 962       char *VertexPointerFunc = (char*) &table->VertexPointer;
 963       GLuint offset = (VertexPointerFunc - (char *) table) / sizeof(void *);
 964       assert(VertexPointerOffset == _gloffset_VertexPointer);
 965       assert(VertexPointerOffset == offset);
 966    }
 967    {
 968       GLuint ResetMinMaxOffset = _glapi_get_proc_offset("glResetMinmax");
 969       char *ResetMinMaxFunc = (char*) &table->ResetMinmax;
 970       GLuint offset = (ResetMinMaxFunc - (char *) table) / sizeof(void *);
 971       assert(ResetMinMaxOffset == _gloffset_ResetMinmax);
 972       assert(ResetMinMaxOffset == offset);
 973    }
 974    {
 975       GLuint blendColorOffset = _glapi_get_proc_offset("glBlendColor");
 976       char *blendColorFunc = (char*) &table->BlendColor;
 977       GLuint offset = (blendColorFunc - (char *) table) / sizeof(void *);
 978       assert(blendColorOffset == _gloffset_BlendColor);
 979       assert(blendColorOffset == offset);
 980    }
 981    {
 982       GLuint istextureOffset = _glapi_get_proc_offset("glIsTextureEXT");
 983       char *istextureFunc = (char*) &table->IsTextureEXT;
 984       GLuint offset = (istextureFunc - (char *) table) / sizeof(void *);
 985       assert(istextureOffset == _gloffset_IsTextureEXT);
 986       assert(istextureOffset == offset);
 987    }
 988    {
 989       GLuint secondaryColor3fOffset = _glapi_get_proc_offset("glSecondaryColor3fEXT");
 990       char *secondaryColor3fFunc = (char*) &table->SecondaryColor3fEXT;
 991       GLuint offset = (secondaryColor3fFunc - (char *) table) / sizeof(void *);
 992       assert(secondaryColor3fOffset == _gloffset_SecondaryColor3fEXT);
 993       assert(secondaryColor3fOffset == offset);
 994       assert(_glapi_get_proc_address("glSecondaryColor3fEXT") == (_glapi_proc) &glSecondaryColor3fEXT);
 995    }
 996    {
 997       GLuint pointParameterivOffset = _glapi_get_proc_offset("glPointParameterivNV");
 998       char *pointParameterivFunc = (char*) &table->PointParameterivNV;
 999       GLuint offset = (pointParameterivFunc - (char *) table) / sizeof(void *);
1000       assert(pointParameterivOffset == _gloffset_PointParameterivNV);
1001       assert(pointParameterivOffset == offset);
1002       assert(_glapi_get_proc_address("glPointParameterivNV") == (_glapi_proc) &glPointParameterivNV);
1003    }
1004    {
1005       GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
1006       char *setFenceFunc = (char*) &table->SetFenceNV;
1007       GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
1008       assert(setFenceOffset == _gloffset_SetFenceNV);
1009       assert(setFenceOffset == offset);
1010       assert(_glapi_get_proc_address("glSetFenceNV") == (_glapi_proc) &glSetFenceNV);
1011    }
1012 #else
1013    (void) table;
1014 #endif
1015 }
1016
1017
1018 #if defined(PTHREADS) || defined(GLX_USE_TLS)
1019 /**
1020  * Perform platform-specific GL API entry-point fixups.
1021  *
1022  *
1023  */
1024 static void
1025 init_glapi_relocs( void )
1026 {
1027 #if defined( USE_X86_ASM ) && defined( GLX_USE_TLS )
1028     extern void * _x86_get_dispatch(void);
1029     const GLubyte * const get_disp = (const GLubyte *) _x86_get_dispatch;
1030     GLubyte * curr_func = (GLubyte *) gl_dispatch_functions_start;
1031
1032
1033     while ( curr_func != (GLubyte *) gl_dispatch_functions_end ) {
1034         (void) memcpy( curr_func, get_disp, 6 );
1035         curr_func += X86_DISPATCH_FUNCTION_SIZE;
1036     }
1037 #endif /* defined( USE_X86_ASM ) && defined( GLX_USE_TLS ) */
1038 }
1039 #endif