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 #include "glapi/glapioffsets.h"
  36
  37
  38 /**********************************************************************
  39  * Static function management.
  40  */
  41
  42
  43 #if !defined(DISPATCH_FUNCTION_SIZE) && !defined(XFree86Server)
  44 # define NEED_FUNCTION_POINTER
  45 #endif
  46 #include "glapi/glprocs.h"
  47
  48
  49 /**
  50  * Search the table of static entrypoint functions for the named function
  51  * and return the corresponding glprocs_table_t entry.
  52  */
  53 static const glprocs_table_t *
  54 get_static_proc( const char * n )
  55 {
  56    GLuint i;
  57    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
  58       const char *testName = gl_string_table + static_functions[i].Name_offset;
  59 #ifdef MANGLE
  60       /* skip the prefix on the name */
  61       if (strcmp(testName, n + 1) == 0)
  62 #else
  63       if (strcmp(testName, n) == 0)
  64 #endif
  65       {
  66          return &static_functions[i];
  67       }
  68    }
  69    return NULL;
  70 }
  71
  72
  73 /**
  74  * Return dispatch table offset of the named static (built-in) function.
  75  * Return -1 if function not found.
  76  */
  77 static GLint
  78 get_static_proc_offset(const char *funcName)
  79 {
  80    const glprocs_table_t * const f = get_static_proc( funcName );
  81    if (f == NULL) {
  82       return -1;
  83    }
  84
  85    return f->Offset;
  86 }
  87
  88
  89 #if !defined(XFree86Server)
  90
  91 /**
  92  * Return dispatch function address for the named static (built-in) function.
  93  * Return NULL if function not found.
  94  */
  95 static _glapi_proc
  96 get_static_proc_address(const char *funcName)
  97 {
  98    const glprocs_table_t * const f = get_static_proc( funcName );
  99    if (f == NULL) {
 100       return NULL;
 101    }
 102
 103 #if defined(DISPATCH_FUNCTION_SIZE) && defined(GLX_INDIRECT_RENDERING)
 104    return (f->Address == NULL)
 105       ? get_entrypoint_address(f->Offset)
 106       : f->Address;
 107 #elif defined(DISPATCH_FUNCTION_SIZE)
 108    return get_entrypoint_address(f->Offset);
 109 #else
 110    return f->Address;
 111 #endif
 112 }
 113
 114 #else
 115
 116 static _glapi_proc
 117 get_static_proc_address(const char *funcName)
 118 {
 119    (void) funcName;
 120    return NULL;
 121 }
 122
 123 #endif /* !defined(XFree86Server) */
 124
 125
 126 /**
 127  * Return the name of the function at the given offset in the dispatch
 128  * table.  For debugging only.
 129  */
 130 static const char *
 131 get_static_proc_name( GLuint offset )
 132 {
 133    GLuint i;
 134    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
 135       if (static_functions[i].Offset == offset) {
 136          return gl_string_table + static_functions[i].Name_offset;
 137       }
 138    }
 139    return NULL;
 140 }
 141
 142
 143
 144 /**********************************************************************
 145  * Extension function management.
 146  */
 147
 148
 149 /**
 150  * Track information about a function added to the GL API.
 151  */
 152 struct _glapi_function {
 153    /**
 154     * Name of the function.
 155     */
 156    const char * name;
 157
 158
 159    /**
 160     * Text string that describes the types of the parameters passed to the
 161     * named function.   Parameter types are converted to characters using the
 162     * following rules:
 163     *   - 'i' for \c GLint, \c GLuint, and \c GLenum
 164     *   - 'p' for any pointer type
 165     *   - 'f' for \c GLfloat and \c GLclampf
 166     *   - 'd' for \c GLdouble and \c GLclampd
 167     */
 168    const char * parameter_signature;
 169
 170
 171    /**
 172     * Offset in the dispatch table where the pointer to the real function is
 173     * located.  If the driver has not requested that the named function be
 174     * added to the dispatch table, this will have the value ~0.
 175     */
 176    unsigned dispatch_offset;
 177
 178
 179    /**
 180     * Pointer to the dispatch stub for the named function.
 181     *
 182     * \todo
 183     * The semantic of this field should be changed slightly.  Currently, it
 184     * is always expected to be non-\c NULL.  However, it would be better to
 185     * only allocate the entry-point stub when the application requests the
 186     * function via \c glXGetProcAddress.  This would save memory for all the
 187     * functions that the driver exports but that the application never wants
 188     * to call.
 189     */
 190    _glapi_proc dispatch_stub;
 191 };
 192
 193
 194 static struct _glapi_function ExtEntryTable[MAX_EXTENSION_FUNCS];
 195 static GLuint NumExtEntryPoints = 0;
 196
 197
 198 static struct _glapi_function *
 199 get_extension_proc(const char *funcName)
 200 {
 201    GLuint i;
 202    for (i = 0; i < NumExtEntryPoints; i++) {
 203       if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
 204          return & ExtEntryTable[i];
 205       }
 206    }
 207    return NULL;
 208 }
 209
 210
 211 static GLint
 212 get_extension_proc_offset(const char *funcName)
 213 {
 214    const struct _glapi_function * const f = get_extension_proc( funcName );
 215    if (f == NULL) {
 216       return -1;
 217    }
 218
 219    return f->dispatch_offset;
 220 }
 221
 222
 223 static _glapi_proc
 224 get_extension_proc_address(const char *funcName)
 225 {
 226    const struct _glapi_function * const f = get_extension_proc( funcName );
 227    if (f == NULL) {
 228       return NULL;
 229    }
 230
 231    return f->dispatch_stub;
 232 }
 233
 234
 235 static const char *
 236 get_extension_proc_name(GLuint offset)
 237 {
 238    GLuint i;
 239    for (i = 0; i < NumExtEntryPoints; i++) {
 240       if (ExtEntryTable[i].dispatch_offset == offset) {
 241          return ExtEntryTable[i].name;
 242       }
 243    }
 244    return NULL;
 245 }
 246
 247
 248 /**
 249  * strdup() is actually not a standard ANSI C or POSIX routine.
 250  * Irix will not define it if ANSI mode is in effect.
 251  */
 252 static char *
 253 str_dup(const char *str)
 254 {
 255    char *copy;
 256    copy = (char*) malloc(strlen(str) + 1);
 257    if (!copy)
 258       return NULL;
 259    strcpy(copy, str);
 260    return copy;
 261 }
 262
 263
 264 /**
 265  * Generate new entrypoint
 266  *
 267  * Use a temporary dispatch offset of ~0 (i.e. -1).  Later, when the driver
 268  * calls \c _glapi_add_dispatch we'll put in the proper offset.  If that
 269  * never happens, and the user calls this function, he'll segfault.  That's
 270  * what you get when you try calling a GL function that doesn't really exist.
 271  *
 272  * \param funcName  Name of the function to create an entry-point for.
 273  *
 274  * \sa _glapi_add_entrypoint
 275  */
 276
 277 static struct _glapi_function *
 278 add_function_name( const char * funcName )
 279 {
 280    struct _glapi_function * entry = NULL;
 281    _glapi_proc entrypoint = NULL;
 282    char * name_dup = NULL;
 283
 284    if (NumExtEntryPoints >= MAX_EXTENSION_FUNCS)
 285       return NULL;
 286
 287    if (funcName == NULL)
 288       return NULL;
 289
 290    name_dup = str_dup(funcName);
 291    if (name_dup == NULL)
 292       return NULL;
 293
 294    entrypoint = generate_entrypoint(~0);
 295
 296    if (entrypoint == NULL) {
 297       free(name_dup);
 298       return NULL;
 299    }
 300
 301    entry = & ExtEntryTable[NumExtEntryPoints];
 302    NumExtEntryPoints++;
 303
 304    entry->name = name_dup;
 305    entry->parameter_signature = NULL;
 306    entry->dispatch_offset = ~0;
 307    entry->dispatch_stub = entrypoint;
 308
 309    return entry;
 310 }
 311
 312
 313 static struct _glapi_function *
 314 set_entry_info( struct _glapi_function * entry, const char * signature, unsigned offset )
 315 {
 316    char * sig_dup = NULL;
 317
 318    if (signature == NULL)
 319       return NULL;
 320
 321    sig_dup = str_dup(signature);
 322    if (sig_dup == NULL)
 323       return NULL;
 324
 325    fill_in_entrypoint_offset(entry->dispatch_stub, offset);
 326
 327    entry->parameter_signature = sig_dup;
 328    entry->dispatch_offset = offset;
 329
 330    return entry;
 331 }
 332
 333
 334 /**
 335  * Fill-in the dispatch stub for the named function.
 336  *
 337  * This function is intended to be called by a hardware driver.  When called,
 338  * a dispatch stub may be created created for the function.  A pointer to this
 339  * dispatch function will be returned by glXGetProcAddress.
 340  *
 341  * \param function_names       Array of pointers to function names that should
 342  *                             share a common dispatch offset.
 343  * \param parameter_signature  String representing the types of the parameters
 344  *                             passed to the named function.  Parameter types
 345  *                             are converted to characters using the following
 346  *                             rules:
 347  *                               - 'i' for \c GLint, \c GLuint, and \c GLenum
 348  *                               - 'p' for any pointer type
 349  *                               - 'f' for \c GLfloat and \c GLclampf
 350  *                               - 'd' for \c GLdouble and \c GLclampd
 351  *
 352  * \returns
 353  * The offset in the dispatch table of the named function.  A pointer to the
 354  * driver's implementation of the named function should be stored at
 355  * \c dispatch_table[\c offset].  Return -1 if error/problem.
 356  *
 357  * \sa glXGetProcAddress
 358  *
 359  * \warning
 360  * This function can only handle up to 8 names at a time.  As far as I know,
 361  * the maximum number of names ever associated with an existing GL function is
 362  * 4 (\c glPointParameterfSGIS, \c glPointParameterfEXT,
 363  * \c glPointParameterfARB, and \c glPointParameterf), so this should not be
 364  * too painful of a limitation.
 365  *
 366  * \todo
 367  * Determine whether or not \c parameter_signature should be allowed to be
 368  * \c NULL.  It doesn't seem like much of a hardship for drivers to have to
 369  * pass in an empty string.
 370  *
 371  * \todo
 372  * Determine if code should be added to reject function names that start with
 373  * 'glX'.
 374  *
 375  * \bug
 376  * Add code to compare \c parameter_signature with the parameter signature of
 377  * a static function.  In order to do that, we need to find a way to \b get
 378  * the parameter signature of a static function.
 379  */
 380
 381 int
 382 _glapi_add_dispatch( const char * const * function_names,
 383                      const char * parameter_signature )
 384 {
 385    static int next_dynamic_offset = _gloffset_FIRST_DYNAMIC;
 386    const char * const real_sig = (parameter_signature != NULL)
 387      ? parameter_signature : "";
 388    struct _glapi_function * entry[8];
 389    GLboolean is_static[8];
 390    unsigned i;
 391    int offset = ~0;
 392
 393    init_glapi_relocs_once();
 394
 395    (void) memset( is_static, 0, sizeof( is_static ) );
 396    (void) memset( entry, 0, sizeof( entry ) );
 397
 398    /* Find the _single_ dispatch offset for all function names that already
 399     * exist (and have a dispatch offset).
 400     */
 401
 402    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 403       const char * funcName = function_names[i];
 404       int static_offset;
 405       int extension_offset;
 406
 407       if (funcName[0] != 'g' || funcName[1] != 'l')
 408          return -1;
 409
 410       /* search built-in functions */
 411       static_offset = get_static_proc_offset(funcName);
 412
 413       if (static_offset >= 0) {
 414
 415          is_static[i] = GL_TRUE;
 416
 417          /* FIXME: Make sure the parameter signatures match!  How do we get
 418           * FIXME: the parameter signature for static functions?
 419           */
 420
 421          if ( (offset != ~0) && (static_offset != offset) ) {
 422             return -1;
 423          }
 424
 425          offset = static_offset;
 426
 427          continue;
 428       }
 429
 430       /* search added extension functions */
 431       entry[i] = get_extension_proc(funcName);
 432
 433       if (entry[i] != NULL) {
 434          extension_offset = entry[i]->dispatch_offset;
 435
 436          /* The offset may be ~0 if the function name was added by
 437           * glXGetProcAddress but never filled in by the driver.
 438           */
 439
 440          if (extension_offset == ~0) {
 441             continue;
 442          }
 443
 444          if (strcmp(real_sig, entry[i]->parameter_signature) != 0) {
 445             return -1;
 446          }
 447
 448          if ( (offset != ~0) && (extension_offset != offset) ) {
 449             return -1;
 450          }
 451
 452          offset = extension_offset;
 453       }
 454    }
 455
 456    /* If all function names are either new (or with no dispatch offset),
 457     * allocate a new dispatch offset.
 458     */
 459
 460    if (offset == ~0) {
 461       offset = next_dynamic_offset;
 462       next_dynamic_offset++;
 463    }
 464
 465    /* Fill in the dispatch offset for the new function names (and those with
 466     * no dispatch offset).
 467     */
 468
 469    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 470       if (is_static[i]) {
 471          continue;
 472       }
 473
 474       /* generate entrypoints for new function names */
 475       if (entry[i] == NULL) {
 476          entry[i] = add_function_name( function_names[i] );
 477          if (entry[i] == NULL) {
 478             /* FIXME: Possible memory leak here. */
 479             return -1;
 480          }
 481       }
 482
 483       if (entry[i]->dispatch_offset == ~0) {
 484          set_entry_info( entry[i], real_sig, offset );
 485       }
 486    }
 487
 488    return offset;
 489 }
 490
 491
 492 /**
 493  * Return offset of entrypoint for named function within dispatch table.
 494  */
 495 GLint
 496 _glapi_get_proc_offset(const char *funcName)
 497 {
 498    GLint offset;
 499
 500    /* search extension functions first */
 501    offset = get_extension_proc_offset(funcName);
 502    if (offset >= 0)
 503       return offset;
 504
 505    /* search static functions */
 506    return get_static_proc_offset(funcName);
 507 }
 508
 509
 510
 511 /**
 512  * Return pointer to the named function.  If the function name isn't found
 513  * in the name of static functions, try generating a new API entrypoint on
 514  * the fly with assembly language.
 515  */
 516 _glapi_proc
 517 _glapi_get_proc_address(const char *funcName)
 518 {
 519    _glapi_proc func;
 520    struct _glapi_function * entry;
 521
 522    init_glapi_relocs_once();
 523
 524 #ifdef MANGLE
 525    /* skip the prefix on the name */
 526    if (funcName[1] != 'g' || funcName[2] != 'l')
 527       return NULL;
 528 #else
 529    if (funcName[0] != 'g' || funcName[1] != 'l')
 530       return NULL;
 531 #endif
 532
 533    /* search extension functions first */
 534    func = get_extension_proc_address(funcName);
 535    if (func)
 536       return func;
 537
 538    /* search static functions */
 539    func = get_static_proc_address(funcName);
 540    if (func)
 541       return func;
 542
 543    /* generate entrypoint, dispatch offset must be filled in by the driver */
 544    entry = add_function_name(funcName);
 545    if (entry == NULL)
 546       return NULL;
 547
 548    return entry->dispatch_stub;
 549 }
 550
 551
 552
 553 /**
 554  * Return the name of the function at the given dispatch offset.
 555  * This is only intended for debugging.
 556  */
 557 const char *
 558 _glapi_get_proc_name(GLuint offset)
 559 {
 560    const char * n;
 561
 562    /* search built-in functions */
 563    n = get_static_proc_name(offset);
 564    if ( n != NULL ) {
 565       return n;
 566    }
 567
 568    /* search added extension functions */
 569    return get_extension_proc_name(offset);
 570 }
 571
 572
 573
 574 /**********************************************************************
 575  * GL API table functions.
 576  */
 577
 578
 579 /*
 580  * The dispatch table size (number of entries) is the size of the
 581  * _glapi_table struct plus the number of dynamic entries we can add.
 582  * The extra slots can be filled in by DRI drivers that register new extension
 583  * functions.
 584  */
 585 #define DISPATCH_TABLE_SIZE (sizeof(struct _glapi_table) / sizeof(void *) + MAX_EXTENSION_FUNCS)
 586
 587
 588 /**
 589  * Return size of dispatch table struct as number of functions (or
 590  * slots).
 591  */
 592 GLuint
 593 _glapi_get_dispatch_table_size(void)
 594 {
 595    return DISPATCH_TABLE_SIZE;
 596 }
 597
 598
 599 /**
 600  * Make sure there are no NULL pointers in the given dispatch table.
 601  * Intended for debugging purposes.
 602  */
 603 void
 604 _glapi_check_table_not_null(const struct _glapi_table *table)
 605 {
 606 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
 607    const GLuint entries = _glapi_get_dispatch_table_size();
 608    const void **tab = (const void **) table;
 609    GLuint i;
 610    for (i = 1; i < entries; i++) {
 611       assert(tab[i]);
 612    }
 613 #else
 614    (void) table;
 615 #endif
 616 }
 617
 618
 619 /**
 620  * Do some spot checks to be sure that the dispatch table
 621  * slots are assigned correctly. For debugging only.
 622  */
 623 void
 624 _glapi_check_table(const struct _glapi_table *table)
 625 {
 626 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
 627    {
 628       GLuint BeginOffset = _glapi_get_proc_offset("glBegin");
 629       char *BeginFunc = (char*) &table->Begin;
 630       GLuint offset = (BeginFunc - (char *) table) / sizeof(void *);
 631       assert(BeginOffset == _gloffset_Begin);
 632       assert(BeginOffset == offset);
 633    }
 634    {
 635       GLuint viewportOffset = _glapi_get_proc_offset("glViewport");
 636       char *viewportFunc = (char*) &table->Viewport;
 637       GLuint offset = (viewportFunc - (char *) table) / sizeof(void *);
 638       assert(viewportOffset == _gloffset_Viewport);
 639       assert(viewportOffset == offset);
 640    }
 641    {
 642       GLuint VertexPointerOffset = _glapi_get_proc_offset("glVertexPointer");
 643       char *VertexPointerFunc = (char*) &table->VertexPointer;
 644       GLuint offset = (VertexPointerFunc - (char *) table) / sizeof(void *);
 645       assert(VertexPointerOffset == _gloffset_VertexPointer);
 646       assert(VertexPointerOffset == offset);
 647    }
 648    {
 649       GLuint ResetMinMaxOffset = _glapi_get_proc_offset("glResetMinmax");
 650       char *ResetMinMaxFunc = (char*) &table->ResetMinmax;
 651       GLuint offset = (ResetMinMaxFunc - (char *) table) / sizeof(void *);
 652       assert(ResetMinMaxOffset == _gloffset_ResetMinmax);
 653       assert(ResetMinMaxOffset == offset);
 654    }
 655    {
 656       GLuint blendColorOffset = _glapi_get_proc_offset("glBlendColor");
 657       char *blendColorFunc = (char*) &table->BlendColor;
 658       GLuint offset = (blendColorFunc - (char *) table) / sizeof(void *);
 659       assert(blendColorOffset == _gloffset_BlendColor);
 660       assert(blendColorOffset == offset);
 661    }
 662    {
 663       GLuint secondaryColor3fOffset = _glapi_get_proc_offset("glSecondaryColor3fEXT");
 664       char *secondaryColor3fFunc = (char*) &table->SecondaryColor3fEXT;
 665       GLuint offset = (secondaryColor3fFunc - (char *) table) / sizeof(void *);
 666       assert(secondaryColor3fOffset == _gloffset_SecondaryColor3fEXT);
 667       assert(secondaryColor3fOffset == offset);
 668    }
 669    {
 670       GLuint pointParameterivOffset = _glapi_get_proc_offset("glPointParameterivNV");
 671       char *pointParameterivFunc = (char*) &table->PointParameterivNV;
 672       GLuint offset = (pointParameterivFunc - (char *) table) / sizeof(void *);
 673       assert(pointParameterivOffset == _gloffset_PointParameterivNV);
 674       assert(pointParameterivOffset == offset);
 675    }
 676    {
 677       GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
 678       char *setFenceFunc = (char*) &table->SetFenceNV;
 679       GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
 680       assert(setFenceOffset == _gloffset_SetFenceNV);
 681       assert(setFenceOffset == offset);
 682    }
 683 #else
 684    (void) table;
 685 #endif
 686 }