src/mapi/glapi/glapi_getproc.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  * \file glapi_getproc.c
  27  *
  28  * Code for implementing glXGetProcAddress(), etc.
  29  * This was originally in glapi.c but refactored out.
  30  */
  31
  32
  33 #include "glapi/glapi_priv.h"
  34 #include "glapi/glapitable.h"
  35
  36
  37 #define FIRST_DYNAMIC_OFFSET (sizeof(struct _glapi_table) / sizeof(void *))
  38
  39
  40 /**********************************************************************
  41  * Static function management.
  42  */
  43
  44
  45 #if !defined(DISPATCH_FUNCTION_SIZE) && !defined(XFree86Server)
  46 # define NEED_FUNCTION_POINTER
  47 #endif
  48 #include "glapi/glprocs.h"
  49
  50
  51 /**
  52  * Search the table of static entrypoint functions for the named function
  53  * and return the corresponding glprocs_table_t entry.
  54  */
  55 static const glprocs_table_t *
  56 get_static_proc( const char * n )
  57 {
  58    GLuint i;
  59    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
  60       const char *testName = gl_string_table + static_functions[i].Name_offset;
  61 #ifdef MANGLE
  62       /* skip the prefix on the name */
  63       if (strcmp(testName, n + 1) == 0)
  64 #else
  65       if (strcmp(testName, n) == 0)
  66 #endif
  67       {
  68          return &static_functions[i];
  69       }
  70    }
  71    return NULL;
  72 }
  73
  74
  75 /**
  76  * Return dispatch table offset of the named static (built-in) function.
  77  * Return -1 if function not found.
  78  */
  79 static GLint
  80 get_static_proc_offset(const char *funcName)
  81 {
  82    const glprocs_table_t * const f = get_static_proc( funcName );
  83    if (f == NULL) {
  84       return -1;
  85    }
  86
  87    return f->Offset;
  88 }
  89
  90
  91 #if !defined(XFree86Server)
  92
  93 /**
  94  * Return dispatch function address for the named static (built-in) function.
  95  * Return NULL if function not found.
  96  */
  97 static _glapi_proc
  98 get_static_proc_address(const char *funcName)
  99 {
 100    const glprocs_table_t * const f = get_static_proc( funcName );
 101    if (f == NULL) {
 102       return NULL;
 103    }
 104
 105 #if defined(DISPATCH_FUNCTION_SIZE) && defined(GLX_INDIRECT_RENDERING)
 106    return (f->Address == NULL)
 107       ? get_entrypoint_address(f->Offset)
 108       : f->Address;
 109 #elif defined(DISPATCH_FUNCTION_SIZE)
 110    return get_entrypoint_address(f->Offset);
 111 #else
 112    return f->Address;
 113 #endif
 114 }
 115
 116 #else
 117
 118 static _glapi_proc
 119 get_static_proc_address(const char *funcName)
 120 {
 121    (void) funcName;
 122    return NULL;
 123 }
 124
 125 #endif /* !defined(XFree86Server) */
 126
 127
 128 /**
 129  * Return the name of the function at the given offset in the dispatch
 130  * table.  For debugging only.
 131  */
 132 static const char *
 133 get_static_proc_name( GLuint offset )
 134 {
 135    GLuint i;
 136    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
 137       if (static_functions[i].Offset == offset) {
 138          return gl_string_table + static_functions[i].Name_offset;
 139       }
 140    }
 141    return NULL;
 142 }
 143
 144
 145
 146 /**********************************************************************
 147  * Extension function management.
 148  */
 149
 150
 151 /**
 152  * Track information about a function added to the GL API.
 153  */
 154 struct _glapi_function {
 155    /**
 156     * Name of the function.
 157     */
 158    const char * name;
 159
 160
 161    /**
 162     * Text string that describes the types of the parameters passed to the
 163     * named function.   Parameter types are converted to characters using the
 164     * following rules:
 165     *   - 'i' for \c GLint, \c GLuint, and \c GLenum
 166     *   - 'p' for any pointer type
 167     *   - 'f' for \c GLfloat and \c GLclampf
 168     *   - 'd' for \c GLdouble and \c GLclampd
 169     */
 170    const char * parameter_signature;
 171
 172
 173    /**
 174     * Offset in the dispatch table where the pointer to the real function is
 175     * located.  If the driver has not requested that the named function be
 176     * added to the dispatch table, this will have the value ~0.
 177     */
 178    unsigned dispatch_offset;
 179
 180
 181    /**
 182     * Pointer to the dispatch stub for the named function.
 183     *
 184     * \todo
 185     * The semantic of this field should be changed slightly.  Currently, it
 186     * is always expected to be non-\c NULL.  However, it would be better to
 187     * only allocate the entry-point stub when the application requests the
 188     * function via \c glXGetProcAddress.  This would save memory for all the
 189     * functions that the driver exports but that the application never wants
 190     * to call.
 191     */
 192    _glapi_proc dispatch_stub;
 193 };
 194
 195
 196 static struct _glapi_function ExtEntryTable[MAX_EXTENSION_FUNCS];
 197 static GLuint NumExtEntryPoints = 0;
 198
 199
 200 static struct _glapi_function *
 201 get_extension_proc(const char *funcName)
 202 {
 203    GLuint i;
 204    for (i = 0; i < NumExtEntryPoints; i++) {
 205       if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
 206          return & ExtEntryTable[i];
 207       }
 208    }
 209    return NULL;
 210 }
 211
 212
 213 static GLint
 214 get_extension_proc_offset(const char *funcName)
 215 {
 216    const struct _glapi_function * const f = get_extension_proc( funcName );
 217    if (f == NULL) {
 218       return -1;
 219    }
 220
 221    return f->dispatch_offset;
 222 }
 223
 224
 225 static _glapi_proc
 226 get_extension_proc_address(const char *funcName)
 227 {
 228    const struct _glapi_function * const f = get_extension_proc( funcName );
 229    if (f == NULL) {
 230       return NULL;
 231    }
 232
 233    return f->dispatch_stub;
 234 }
 235
 236
 237 static const char *
 238 get_extension_proc_name(GLuint offset)
 239 {
 240    GLuint i;
 241    for (i = 0; i < NumExtEntryPoints; i++) {
 242       if (ExtEntryTable[i].dispatch_offset == offset) {
 243          return ExtEntryTable[i].name;
 244       }
 245    }
 246    return NULL;
 247 }
 248
 249
 250 /**
 251  * strdup() is actually not a standard ANSI C or POSIX routine.
 252  * Irix will not define it if ANSI mode is in effect.
 253  */
 254 static char *
 255 str_dup(const char *str)
 256 {
 257    char *copy;
 258    copy = (char*) malloc(strlen(str) + 1);
 259    if (!copy)
 260       return NULL;
 261    strcpy(copy, str);
 262    return copy;
 263 }
 264
 265
 266 /**
 267  * Generate new entrypoint
 268  *
 269  * Use a temporary dispatch offset of ~0 (i.e. -1).  Later, when the driver
 270  * calls \c _glapi_add_dispatch we'll put in the proper offset.  If that
 271  * never happens, and the user calls this function, he'll segfault.  That's
 272  * what you get when you try calling a GL function that doesn't really exist.
 273  *
 274  * \param funcName  Name of the function to create an entry-point for.
 275  *
 276  * \sa _glapi_add_entrypoint
 277  */
 278
 279 static struct _glapi_function *
 280 add_function_name( const char * funcName )
 281 {
 282    struct _glapi_function * entry = NULL;
 283    _glapi_proc entrypoint = NULL;
 284    char * name_dup = NULL;
 285
 286    if (NumExtEntryPoints >= MAX_EXTENSION_FUNCS)
 287       return NULL;
 288
 289    if (funcName == NULL)
 290       return NULL;
 291
 292    name_dup = str_dup(funcName);
 293    if (name_dup == NULL)
 294       return NULL;
 295
 296    entrypoint = generate_entrypoint(~0);
 297
 298    if (entrypoint == NULL) {
 299       free(name_dup);
 300       return NULL;
 301    }
 302
 303    entry = & ExtEntryTable[NumExtEntryPoints];
 304    NumExtEntryPoints++;
 305
 306    entry->name = name_dup;
 307    entry->parameter_signature = NULL;
 308    entry->dispatch_offset = ~0;
 309    entry->dispatch_stub = entrypoint;
 310
 311    return entry;
 312 }
 313
 314
 315 static struct _glapi_function *
 316 set_entry_info( struct _glapi_function * entry, const char * signature, unsigned offset )
 317 {
 318    char * sig_dup = NULL;
 319
 320    if (signature == NULL)
 321       return NULL;
 322
 323    sig_dup = str_dup(signature);
 324    if (sig_dup == NULL)
 325       return NULL;
 326
 327    fill_in_entrypoint_offset(entry->dispatch_stub, offset);
 328
 329    entry->parameter_signature = sig_dup;
 330    entry->dispatch_offset = offset;
 331
 332    return entry;
 333 }
 334
 335
 336 /**
 337  * Fill-in the dispatch stub for the named function.
 338  *
 339  * This function is intended to be called by a hardware driver.  When called,
 340  * a dispatch stub may be created created for the function.  A pointer to this
 341  * dispatch function will be returned by glXGetProcAddress.
 342  *
 343  * \param function_names       Array of pointers to function names that should
 344  *                             share a common dispatch offset.
 345  * \param parameter_signature  String representing the types of the parameters
 346  *                             passed to the named function.  Parameter types
 347  *                             are converted to characters using the following
 348  *                             rules:
 349  *                               - 'i' for \c GLint, \c GLuint, and \c GLenum
 350  *                               - 'p' for any pointer type
 351  *                               - 'f' for \c GLfloat and \c GLclampf
 352  *                               - 'd' for \c GLdouble and \c GLclampd
 353  *
 354  * \returns
 355  * The offset in the dispatch table of the named function.  A pointer to the
 356  * driver's implementation of the named function should be stored at
 357  * \c dispatch_table[\c offset].  Return -1 if error/problem.
 358  *
 359  * \sa glXGetProcAddress
 360  *
 361  * \warning
 362  * This function can only handle up to 8 names at a time.  As far as I know,
 363  * the maximum number of names ever associated with an existing GL function is
 364  * 4 (\c glPointParameterfSGIS, \c glPointParameterfEXT,
 365  * \c glPointParameterfARB, and \c glPointParameterf), so this should not be
 366  * too painful of a limitation.
 367  *
 368  * \todo
 369  * Determine whether or not \c parameter_signature should be allowed to be
 370  * \c NULL.  It doesn't seem like much of a hardship for drivers to have to
 371  * pass in an empty string.
 372  *
 373  * \todo
 374  * Determine if code should be added to reject function names that start with
 375  * 'glX'.
 376  *
 377  * \bug
 378  * Add code to compare \c parameter_signature with the parameter signature of
 379  * a static function.  In order to do that, we need to find a way to \b get
 380  * the parameter signature of a static function.
 381  */
 382
 383 int
 384 _glapi_add_dispatch( const char * const * function_names,
 385                      const char * parameter_signature )
 386 {
 387    static int next_dynamic_offset = FIRST_DYNAMIC_OFFSET;
 388    const char * const real_sig = (parameter_signature != NULL)
 389      ? parameter_signature : "";
 390    struct _glapi_function * entry[8];
 391    GLboolean is_static[8];
 392    unsigned i;
 393    int offset = ~0;
 394
 395    init_glapi_relocs_once();
 396
 397    (void) memset( is_static, 0, sizeof( is_static ) );
 398    (void) memset( entry, 0, sizeof( entry ) );
 399
 400    /* Find the _single_ dispatch offset for all function names that already
 401     * exist (and have a dispatch offset).
 402     */
 403
 404    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 405       const char * funcName = function_names[i];
 406       int static_offset;
 407       int extension_offset;
 408
 409       if (funcName[0] != 'g' || funcName[1] != 'l')
 410          return -1;
 411
 412       /* search built-in functions */
 413       static_offset = get_static_proc_offset(funcName);
 414
 415       if (static_offset >= 0) {
 416
 417          is_static[i] = GL_TRUE;
 418
 419          /* FIXME: Make sure the parameter signatures match!  How do we get
 420           * FIXME: the parameter signature for static functions?
 421           */
 422
 423          if ( (offset != ~0) && (static_offset != offset) ) {
 424             return -1;
 425          }
 426
 427          offset = static_offset;
 428
 429          continue;
 430       }
 431
 432       /* search added extension functions */
 433       entry[i] = get_extension_proc(funcName);
 434
 435       if (entry[i] != NULL) {
 436          extension_offset = entry[i]->dispatch_offset;
 437
 438          /* The offset may be ~0 if the function name was added by
 439           * glXGetProcAddress but never filled in by the driver.
 440           */
 441
 442          if (extension_offset == ~0) {
 443             continue;
 444          }
 445
 446          if (strcmp(real_sig, entry[i]->parameter_signature) != 0) {
 447             return -1;
 448          }
 449
 450          if ( (offset != ~0) && (extension_offset != offset) ) {
 451             return -1;
 452          }
 453
 454          offset = extension_offset;
 455       }
 456    }
 457
 458    /* If all function names are either new (or with no dispatch offset),
 459     * allocate a new dispatch offset.
 460     */
 461
 462    if (offset == ~0) {
 463       offset = next_dynamic_offset;
 464       next_dynamic_offset++;
 465    }
 466
 467    /* Fill in the dispatch offset for the new function names (and those with
 468     * no dispatch offset).
 469     */
 470
 471    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 472       if (is_static[i]) {
 473          continue;
 474       }
 475
 476       /* generate entrypoints for new function names */
 477       if (entry[i] == NULL) {
 478          entry[i] = add_function_name( function_names[i] );
 479          if (entry[i] == NULL) {
 480             /* FIXME: Possible memory leak here. */
 481             return -1;
 482          }
 483       }
 484
 485       if (entry[i]->dispatch_offset == ~0) {
 486          set_entry_info( entry[i], real_sig, offset );
 487       }
 488    }
 489
 490    return offset;
 491 }
 492
 493
 494 /**
 495  * Return offset of entrypoint for named function within dispatch table.
 496  */
 497 GLint
 498 _glapi_get_proc_offset(const char *funcName)
 499 {
 500    GLint offset;
 501
 502    /* search extension functions first */
 503    offset = get_extension_proc_offset(funcName);
 504    if (offset >= 0)
 505       return offset;
 506
 507    /* search static functions */
 508    return get_static_proc_offset(funcName);
 509 }
 510
 511
 512
 513 /**
 514  * Return pointer to the named function.  If the function name isn't found
 515  * in the name of static functions, try generating a new API entrypoint on
 516  * the fly with assembly language.
 517  */
 518 _glapi_proc
 519 _glapi_get_proc_address(const char *funcName)
 520 {
 521    _glapi_proc func;
 522    struct _glapi_function * entry;
 523
 524    init_glapi_relocs_once();
 525
 526 #ifdef MANGLE
 527    /* skip the prefix on the name */
 528    if (funcName[1] != 'g' || funcName[2] != 'l')
 529       return NULL;
 530 #else
 531    if (funcName[0] != 'g' || funcName[1] != 'l')
 532       return NULL;
 533 #endif
 534
 535    /* search extension functions first */
 536    func = get_extension_proc_address(funcName);
 537    if (func)
 538       return func;
 539
 540    /* search static functions */
 541    func = get_static_proc_address(funcName);
 542    if (func)
 543       return func;
 544
 545    /* generate entrypoint, dispatch offset must be filled in by the driver */
 546    entry = add_function_name(funcName);
 547    if (entry == NULL)
 548       return NULL;
 549
 550    return entry->dispatch_stub;
 551 }
 552
 553
 554
 555 /**
 556  * Return the name of the function at the given dispatch offset.
 557  * This is only intended for debugging.
 558  */
 559 const char *
 560 _glapi_get_proc_name(GLuint offset)
 561 {
 562    const char * n;
 563
 564    /* search built-in functions */
 565    n = get_static_proc_name(offset);
 566    if ( n != NULL ) {
 567       return n;
 568    }
 569
 570    /* search added extension functions */
 571    return get_extension_proc_name(offset);
 572 }
 573
 574
 575
 576 /**********************************************************************
 577  * GL API table functions.
 578  */
 579
 580
 581 /**
 582  * Return size of dispatch table struct as number of functions (or
 583  * slots).
 584  */
 585 GLuint
 586 _glapi_get_dispatch_table_size(void)
 587 {
 588    /*
 589     * The dispatch table size (number of entries) is the size of the
 590     * _glapi_table struct plus the number of dynamic entries we can add.
 591     * The extra slots can be filled in by DRI drivers that register new
 592     * extension functions.
 593     */
 594    return FIRST_DYNAMIC_OFFSET + MAX_EXTENSION_FUNCS;
 595 }
 596
 597
 598 /**
 599  * Make sure there are no NULL pointers in the given dispatch table.
 600  * Intended for debugging purposes.
 601  */
 602 void
 603 _glapi_check_table_not_null(const struct _glapi_table *table)
 604 {
 605 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
 606    const GLuint entries = _glapi_get_dispatch_table_size();
 607    const void **tab = (const void **) table;
 608    GLuint i;
 609    for (i = 1; i < entries; i++) {
 610       assert(tab[i]);
 611    }
 612 #else
 613    (void) table;
 614 #endif
 615 }
 616
 617
 618 /**
 619  * Do some spot checks to be sure that the dispatch table
 620  * slots are assigned correctly. For debugging only.
 621  */
 622 void
 623 _glapi_check_table(const struct _glapi_table *table)
 624 {
 625 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
 626    {
 627       GLuint BeginOffset = _glapi_get_proc_offset("glBegin");
 628       char *BeginFunc = (char*) &table->Begin;
 629       GLuint offset = (BeginFunc - (char *) table) / sizeof(void *);
 630       assert(BeginOffset == offset);
 631    }
 632    {
 633       GLuint viewportOffset = _glapi_get_proc_offset("glViewport");
 634       char *viewportFunc = (char*) &table->Viewport;
 635       GLuint offset = (viewportFunc - (char *) table) / sizeof(void *);
 636       assert(viewportOffset == offset);
 637    }
 638    {
 639       GLuint VertexPointerOffset = _glapi_get_proc_offset("glVertexPointer");
 640       char *VertexPointerFunc = (char*) &table->VertexPointer;
 641       GLuint offset = (VertexPointerFunc - (char *) table) / sizeof(void *);
 642       assert(VertexPointerOffset == offset);
 643    }
 644    {
 645       GLuint ResetMinMaxOffset = _glapi_get_proc_offset("glResetMinmax");
 646       char *ResetMinMaxFunc = (char*) &table->ResetMinmax;
 647       GLuint offset = (ResetMinMaxFunc - (char *) table) / sizeof(void *);
 648       assert(ResetMinMaxOffset == offset);
 649    }
 650    {
 651       GLuint blendColorOffset = _glapi_get_proc_offset("glBlendColor");
 652       char *blendColorFunc = (char*) &table->BlendColor;
 653       GLuint offset = (blendColorFunc - (char *) table) / sizeof(void *);
 654       assert(blendColorOffset == offset);
 655    }
 656    {
 657       GLuint secondaryColor3fOffset = _glapi_get_proc_offset("glSecondaryColor3fEXT");
 658       char *secondaryColor3fFunc = (char*) &table->SecondaryColor3fEXT;
 659       GLuint offset = (secondaryColor3fFunc - (char *) table) / sizeof(void *);
 660       assert(secondaryColor3fOffset == offset);
 661    }
 662    {
 663       GLuint pointParameterivOffset = _glapi_get_proc_offset("glPointParameterivNV");
 664       char *pointParameterivFunc = (char*) &table->PointParameterivNV;
 665       GLuint offset = (pointParameterivFunc - (char *) table) / sizeof(void *);
 666       assert(pointParameterivOffset == offset);
 667    }
 668    {
 669       GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
 670       char *setFenceFunc = (char*) &table->SetFenceNV;
 671       GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
 672       assert(setFenceOffset == offset);
 673    }
 674 #else
 675    (void) table;
 676 #endif
 677 }