src/mesa/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 #ifdef HAVE_DIX_CONFIG_H
  34 #include <dix-config.h>
  35 #include "glapi/mesa.h"
  36 #else
  37 #include "main/glheader.h"
  38 #include "main/compiler.h"
  39 #endif
  40
  41 #include "glapi/glapi.h"
  42 #include "glapi/glapi_priv.h"
  43 #include "glapi/glapitable.h"
  44 #include "glapi/glapioffsets.h"
  45
  46
  47 /**********************************************************************
  48  * Static function management.
  49  */
  50
  51
  52 #if !defined(DISPATCH_FUNCTION_SIZE) && !defined(XFree86Server)
  53 # define NEED_FUNCTION_POINTER
  54 #endif
  55 #include "glapi/glprocs.h"
  56
  57
  58 /**
  59  * Search the table of static entrypoint functions for the named function
  60  * and return the corresponding glprocs_table_t entry.
  61  */
  62 static const glprocs_table_t *
  63 get_static_proc( const char * n )
  64 {
  65    GLuint i;
  66    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
  67       const char *testName = gl_string_table + static_functions[i].Name_offset;
  68 #ifdef MANGLE
  69       /* skip the prefix on the name */
  70       if (strcmp(testName, n + 1) == 0)
  71 #else
  72       if (strcmp(testName, n) == 0)
  73 #endif
  74       {
  75          return &static_functions[i];
  76       }
  77    }
  78    return NULL;
  79 }
  80
  81
  82 /**
  83  * Return dispatch table offset of the named static (built-in) function.
  84  * Return -1 if function not found.
  85  */
  86 static GLint
  87 get_static_proc_offset(const char *funcName)
  88 {
  89    const glprocs_table_t * const f = get_static_proc( funcName );
  90    if (f == NULL) {
  91       return -1;
  92    }
  93
  94    return f->Offset;
  95 }
  96
  97
  98 #if !defined(XFree86Server)
  99
 100 /**
 101  * Return dispatch function address for the named static (built-in) function.
 102  * Return NULL if function not found.
 103  */
 104 static _glapi_proc
 105 get_static_proc_address(const char *funcName)
 106 {
 107    const glprocs_table_t * const f = get_static_proc( funcName );
 108    if (f == NULL) {
 109       return NULL;
 110    }
 111
 112 #if defined(DISPATCH_FUNCTION_SIZE) && defined(GLX_INDIRECT_RENDERING)
 113    return (f->Address == NULL)
 114       ? get_entrypoint_address(f->Offset)
 115       : f->Address;
 116 #elif defined(DISPATCH_FUNCTION_SIZE)
 117    return get_entrypoint_address(f->Offset);
 118 #else
 119    return f->Address;
 120 #endif
 121 }
 122
 123 #else
 124
 125 static _glapi_proc
 126 get_static_proc_address(const char *funcName)
 127 {
 128    (void) funcName;
 129    return NULL;
 130 }
 131
 132 #endif /* !defined(XFree86Server) */
 133
 134
 135 /**
 136  * Return the name of the function at the given offset in the dispatch
 137  * table.  For debugging only.
 138  */
 139 static const char *
 140 get_static_proc_name( GLuint offset )
 141 {
 142    GLuint i;
 143    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
 144       if (static_functions[i].Offset == offset) {
 145          return gl_string_table + static_functions[i].Name_offset;
 146       }
 147    }
 148    return NULL;
 149 }
 150
 151
 152
 153 /**********************************************************************
 154  * Extension function management.
 155  */
 156
 157
 158 /**
 159  * Track information about a function added to the GL API.
 160  */
 161 struct _glapi_function {
 162    /**
 163     * Name of the function.
 164     */
 165    const char * name;
 166
 167
 168    /**
 169     * Text string that describes the types of the parameters passed to the
 170     * named function.   Parameter types are converted to characters using the
 171     * following rules:
 172     *   - 'i' for \c GLint, \c GLuint, and \c GLenum
 173     *   - 'p' for any pointer type
 174     *   - 'f' for \c GLfloat and \c GLclampf
 175     *   - 'd' for \c GLdouble and \c GLclampd
 176     */
 177    const char * parameter_signature;
 178
 179
 180    /**
 181     * Offset in the dispatch table where the pointer to the real function is
 182     * located.  If the driver has not requested that the named function be
 183     * added to the dispatch table, this will have the value ~0.
 184     */
 185    unsigned dispatch_offset;
 186
 187
 188    /**
 189     * Pointer to the dispatch stub for the named function.
 190     *
 191     * \todo
 192     * The semantic of this field should be changed slightly.  Currently, it
 193     * is always expected to be non-\c NULL.  However, it would be better to
 194     * only allocate the entry-point stub when the application requests the
 195     * function via \c glXGetProcAddress.  This would save memory for all the
 196     * functions that the driver exports but that the application never wants
 197     * to call.
 198     */
 199    _glapi_proc dispatch_stub;
 200 };
 201
 202
 203 static struct _glapi_function ExtEntryTable[MAX_EXTENSION_FUNCS];
 204 static GLuint NumExtEntryPoints = 0;
 205
 206
 207 static struct _glapi_function *
 208 get_extension_proc(const char *funcName)
 209 {
 210    GLuint i;
 211    for (i = 0; i < NumExtEntryPoints; i++) {
 212       if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
 213          return & ExtEntryTable[i];
 214       }
 215    }
 216    return NULL;
 217 }
 218
 219
 220 static GLint
 221 get_extension_proc_offset(const char *funcName)
 222 {
 223    const struct _glapi_function * const f = get_extension_proc( funcName );
 224    if (f == NULL) {
 225       return -1;
 226    }
 227
 228    return f->dispatch_offset;
 229 }
 230
 231
 232 static _glapi_proc
 233 get_extension_proc_address(const char *funcName)
 234 {
 235    const struct _glapi_function * const f = get_extension_proc( funcName );
 236    if (f == NULL) {
 237       return NULL;
 238    }
 239
 240    return f->dispatch_stub;
 241 }
 242
 243
 244 static const char *
 245 get_extension_proc_name(GLuint offset)
 246 {
 247    GLuint i;
 248    for (i = 0; i < NumExtEntryPoints; i++) {
 249       if (ExtEntryTable[i].dispatch_offset == offset) {
 250          return ExtEntryTable[i].name;
 251       }
 252    }
 253    return NULL;
 254 }
 255
 256
 257 /**
 258  * strdup() is actually not a standard ANSI C or POSIX routine.
 259  * Irix will not define it if ANSI mode is in effect.
 260  */
 261 static char *
 262 str_dup(const char *str)
 263 {
 264    char *copy;
 265    copy = (char*) malloc(strlen(str) + 1);
 266    if (!copy)
 267       return NULL;
 268    strcpy(copy, str);
 269    return copy;
 270 }
 271
 272
 273 /**
 274  * Generate new entrypoint
 275  *
 276  * Use a temporary dispatch offset of ~0 (i.e. -1).  Later, when the driver
 277  * calls \c _glapi_add_dispatch we'll put in the proper offset.  If that
 278  * never happens, and the user calls this function, he'll segfault.  That's
 279  * what you get when you try calling a GL function that doesn't really exist.
 280  *
 281  * \param funcName  Name of the function to create an entry-point for.
 282  *
 283  * \sa _glapi_add_entrypoint
 284  */
 285
 286 static struct _glapi_function *
 287 add_function_name( const char * funcName )
 288 {
 289    struct _glapi_function * entry = NULL;
 290    _glapi_proc entrypoint = NULL;
 291    char * name_dup = NULL;
 292
 293    if (NumExtEntryPoints >= MAX_EXTENSION_FUNCS)
 294       return NULL;
 295
 296    if (funcName == NULL)
 297       return NULL;
 298
 299    name_dup = str_dup(funcName);
 300    if (name_dup == NULL)
 301       return NULL;
 302
 303    entrypoint = generate_entrypoint(~0);
 304
 305    if (entrypoint == NULL) {
 306       free(name_dup);
 307       return NULL;
 308    }
 309
 310    entry = & ExtEntryTable[NumExtEntryPoints];
 311    NumExtEntryPoints++;
 312
 313    entry->name = name_dup;
 314    entry->parameter_signature = NULL;
 315    entry->dispatch_offset = ~0;
 316    entry->dispatch_stub = entrypoint;
 317
 318    return entry;
 319 }
 320
 321
 322 static struct _glapi_function *
 323 set_entry_info( struct _glapi_function * entry, const char * signature, unsigned offset )
 324 {
 325    char * sig_dup = NULL;
 326
 327    if (signature == NULL)
 328       return NULL;
 329
 330    sig_dup = str_dup(signature);
 331    if (sig_dup == NULL)
 332       return NULL;
 333
 334    fill_in_entrypoint_offset(entry->dispatch_stub, offset);
 335
 336    entry->parameter_signature = sig_dup;
 337    entry->dispatch_offset = offset;
 338
 339    return entry;
 340 }
 341
 342
 343 /**
 344  * Fill-in the dispatch stub for the named function.
 345  *
 346  * This function is intended to be called by a hardware driver.  When called,
 347  * a dispatch stub may be created created for the function.  A pointer to this
 348  * dispatch function will be returned by glXGetProcAddress.
 349  *
 350  * \param function_names       Array of pointers to function names that should
 351  *                             share a common dispatch offset.
 352  * \param parameter_signature  String representing the types of the parameters
 353  *                             passed to the named function.  Parameter types
 354  *                             are converted to characters using the following
 355  *                             rules:
 356  *                               - 'i' for \c GLint, \c GLuint, and \c GLenum
 357  *                               - 'p' for any pointer type
 358  *                               - 'f' for \c GLfloat and \c GLclampf
 359  *                               - 'd' for \c GLdouble and \c GLclampd
 360  *
 361  * \returns
 362  * The offset in the dispatch table of the named function.  A pointer to the
 363  * driver's implementation of the named function should be stored at
 364  * \c dispatch_table[\c offset].  Return -1 if error/problem.
 365  *
 366  * \sa glXGetProcAddress
 367  *
 368  * \warning
 369  * This function can only handle up to 8 names at a time.  As far as I know,
 370  * the maximum number of names ever associated with an existing GL function is
 371  * 4 (\c glPointParameterfSGIS, \c glPointParameterfEXT,
 372  * \c glPointParameterfARB, and \c glPointParameterf), so this should not be
 373  * too painful of a limitation.
 374  *
 375  * \todo
 376  * Determine whether or not \c parameter_signature should be allowed to be
 377  * \c NULL.  It doesn't seem like much of a hardship for drivers to have to
 378  * pass in an empty string.
 379  *
 380  * \todo
 381  * Determine if code should be added to reject function names that start with
 382  * 'glX'.
 383  *
 384  * \bug
 385  * Add code to compare \c parameter_signature with the parameter signature of
 386  * a static function.  In order to do that, we need to find a way to \b get
 387  * the parameter signature of a static function.
 388  */
 389
 390 PUBLIC int
 391 _glapi_add_dispatch( const char * const * function_names,
 392                      const char * parameter_signature )
 393 {
 394    static int next_dynamic_offset = _gloffset_FIRST_DYNAMIC;
 395    const char * const real_sig = (parameter_signature != NULL)
 396      ? parameter_signature : "";
 397    struct _glapi_function * entry[8];
 398    GLboolean is_static[8];
 399    unsigned i;
 400    int offset = ~0;
 401
 402    init_glapi_relocs_once();
 403
 404    (void) memset( is_static, 0, sizeof( is_static ) );
 405    (void) memset( entry, 0, sizeof( entry ) );
 406
 407    /* Find the _single_ dispatch offset for all function names that already
 408     * exist (and have a dispatch offset).
 409     */
 410
 411    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 412       const char * funcName = function_names[i];
 413       int static_offset;
 414       int extension_offset;
 415
 416       if (funcName[0] != 'g' || funcName[1] != 'l')
 417          return -1;
 418
 419       /* search built-in functions */
 420       static_offset = get_static_proc_offset(funcName);
 421
 422       if (static_offset >= 0) {
 423
 424          is_static[i] = GL_TRUE;
 425
 426          /* FIXME: Make sure the parameter signatures match!  How do we get
 427           * FIXME: the parameter signature for static functions?
 428           */
 429
 430          if ( (offset != ~0) && (static_offset != offset) ) {
 431             return -1;
 432          }
 433
 434          offset = static_offset;
 435
 436          continue;
 437       }
 438
 439       /* search added extension functions */
 440       entry[i] = get_extension_proc(funcName);
 441
 442       if (entry[i] != NULL) {
 443          extension_offset = entry[i]->dispatch_offset;
 444
 445          /* The offset may be ~0 if the function name was added by
 446           * glXGetProcAddress but never filled in by the driver.
 447           */
 448
 449          if (extension_offset == ~0) {
 450             continue;
 451          }
 452
 453          if (strcmp(real_sig, entry[i]->parameter_signature) != 0) {
 454             return -1;
 455          }
 456
 457          if ( (offset != ~0) && (extension_offset != offset) ) {
 458             return -1;
 459          }
 460
 461          offset = extension_offset;
 462       }
 463    }
 464
 465    /* If all function names are either new (or with no dispatch offset),
 466     * allocate a new dispatch offset.
 467     */
 468
 469    if (offset == ~0) {
 470       offset = next_dynamic_offset;
 471       next_dynamic_offset++;
 472    }
 473
 474    /* Fill in the dispatch offset for the new function names (and those with
 475     * no dispatch offset).
 476     */
 477
 478    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 479       if (is_static[i]) {
 480          continue;
 481       }
 482
 483       /* generate entrypoints for new function names */
 484       if (entry[i] == NULL) {
 485          entry[i] = add_function_name( function_names[i] );
 486          if (entry[i] == NULL) {
 487             /* FIXME: Possible memory leak here. */
 488             return -1;
 489          }
 490       }
 491
 492       if (entry[i]->dispatch_offset == ~0) {
 493          set_entry_info( entry[i], real_sig, offset );
 494       }
 495    }
 496
 497    return offset;
 498 }
 499
 500
 501 /**
 502  * Return offset of entrypoint for named function within dispatch table.
 503  */
 504 PUBLIC GLint
 505 _glapi_get_proc_offset(const char *funcName)
 506 {
 507    GLint offset;
 508
 509    /* search extension functions first */
 510    offset = get_extension_proc_offset(funcName);
 511    if (offset >= 0)
 512       return offset;
 513
 514    /* search static functions */
 515    return get_static_proc_offset(funcName);
 516 }
 517
 518
 519
 520 /**
 521  * Return pointer to the named function.  If the function name isn't found
 522  * in the name of static functions, try generating a new API entrypoint on
 523  * the fly with assembly language.
 524  */
 525 PUBLIC _glapi_proc
 526 _glapi_get_proc_address(const char *funcName)
 527 {
 528    _glapi_proc func;
 529    struct _glapi_function * entry;
 530
 531    init_glapi_relocs_once();
 532
 533 #ifdef MANGLE
 534    /* skip the prefix on the name */
 535    if (funcName[1] != 'g' || funcName[2] != 'l')
 536       return NULL;
 537 #else
 538    if (funcName[0] != 'g' || funcName[1] != 'l')
 539       return NULL;
 540 #endif
 541
 542    /* search extension functions first */
 543    func = get_extension_proc_address(funcName);
 544    if (func)
 545       return func;
 546
 547    /* search static functions */
 548    func = get_static_proc_address(funcName);
 549    if (func)
 550       return func;
 551
 552    /* generate entrypoint, dispatch offset must be filled in by the driver */
 553    entry = add_function_name(funcName);
 554    if (entry == NULL)
 555       return NULL;
 556
 557    return entry->dispatch_stub;
 558 }
 559
 560
 561
 562 /**
 563  * Return the name of the function at the given dispatch offset.
 564  * This is only intended for debugging.
 565  */
 566 const char *
 567 _glapi_get_proc_name(GLuint offset)
 568 {
 569    const char * n;
 570
 571    /* search built-in functions */
 572    n = get_static_proc_name(offset);
 573    if ( n != NULL ) {
 574       return n;
 575    }
 576
 577    /* search added extension functions */
 578    return get_extension_proc_name(offset);
 579 }
 580
 581
 582
 583 /**********************************************************************
 584  * GL API table functions.
 585  */
 586
 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 extension
 592  * functions.
 593  */
 594 #define DISPATCH_TABLE_SIZE (sizeof(struct _glapi_table) / sizeof(void *) + MAX_EXTENSION_FUNCS)
 595
 596
 597 /**
 598  * Return size of dispatch table struct as number of functions (or
 599  * slots).
 600  */
 601 PUBLIC GLuint
 602 _glapi_get_dispatch_table_size(void)
 603 {
 604    return DISPATCH_TABLE_SIZE;
 605 }
 606
 607
 608 /**
 609  * Make sure there are no NULL pointers in the given dispatch table.
 610  * Intended for debugging purposes.
 611  */
 612 void
 613 _glapi_check_table_not_null(const struct _glapi_table *table)
 614 {
 615 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
 616    const GLuint entries = _glapi_get_dispatch_table_size();
 617    const void **tab = (const void **) table;
 618    GLuint i;
 619    for (i = 1; i < entries; i++) {
 620       assert(tab[i]);
 621    }
 622 #else
 623    (void) table;
 624 #endif
 625 }
 626
 627
 628 /**
 629  * Do some spot checks to be sure that the dispatch table
 630  * slots are assigned correctly. For debugging only.
 631  */
 632 void
 633 _glapi_check_table(const struct _glapi_table *table)
 634 {
 635 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
 636    {
 637       GLuint BeginOffset = _glapi_get_proc_offset("glBegin");
 638       char *BeginFunc = (char*) &table->Begin;
 639       GLuint offset = (BeginFunc - (char *) table) / sizeof(void *);
 640       assert(BeginOffset == _gloffset_Begin);
 641       assert(BeginOffset == offset);
 642    }
 643    {
 644       GLuint viewportOffset = _glapi_get_proc_offset("glViewport");
 645       char *viewportFunc = (char*) &table->Viewport;
 646       GLuint offset = (viewportFunc - (char *) table) / sizeof(void *);
 647       assert(viewportOffset == _gloffset_Viewport);
 648       assert(viewportOffset == offset);
 649    }
 650    {
 651       GLuint VertexPointerOffset = _glapi_get_proc_offset("glVertexPointer");
 652       char *VertexPointerFunc = (char*) &table->VertexPointer;
 653       GLuint offset = (VertexPointerFunc - (char *) table) / sizeof(void *);
 654       assert(VertexPointerOffset == _gloffset_VertexPointer);
 655       assert(VertexPointerOffset == offset);
 656    }
 657    {
 658       GLuint ResetMinMaxOffset = _glapi_get_proc_offset("glResetMinmax");
 659       char *ResetMinMaxFunc = (char*) &table->ResetMinmax;
 660       GLuint offset = (ResetMinMaxFunc - (char *) table) / sizeof(void *);
 661       assert(ResetMinMaxOffset == _gloffset_ResetMinmax);
 662       assert(ResetMinMaxOffset == offset);
 663    }
 664    {
 665       GLuint blendColorOffset = _glapi_get_proc_offset("glBlendColor");
 666       char *blendColorFunc = (char*) &table->BlendColor;
 667       GLuint offset = (blendColorFunc - (char *) table) / sizeof(void *);
 668       assert(blendColorOffset == _gloffset_BlendColor);
 669       assert(blendColorOffset == offset);
 670    }
 671    {
 672       GLuint secondaryColor3fOffset = _glapi_get_proc_offset("glSecondaryColor3fEXT");
 673       char *secondaryColor3fFunc = (char*) &table->SecondaryColor3fEXT;
 674       GLuint offset = (secondaryColor3fFunc - (char *) table) / sizeof(void *);
 675       assert(secondaryColor3fOffset == _gloffset_SecondaryColor3fEXT);
 676       assert(secondaryColor3fOffset == offset);
 677    }
 678    {
 679       GLuint pointParameterivOffset = _glapi_get_proc_offset("glPointParameterivNV");
 680       char *pointParameterivFunc = (char*) &table->PointParameterivNV;
 681       GLuint offset = (pointParameterivFunc - (char *) table) / sizeof(void *);
 682       assert(pointParameterivOffset == _gloffset_PointParameterivNV);
 683       assert(pointParameterivOffset == offset);
 684    }
 685    {
 686       GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
 687       char *setFenceFunc = (char*) &table->SetFenceNV;
 688       GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
 689       assert(setFenceOffset == _gloffset_SetFenceNV);
 690       assert(setFenceOffset == offset);
 691    }
 692 #else
 693    (void) table;
 694 #endif
 695 }