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 /*
 204  * Number of extension functions which we can dynamically add at runtime.
 205  */
 206 #define MAX_EXTENSION_FUNCS 300
 207
 208
 209 static struct _glapi_function ExtEntryTable[MAX_EXTENSION_FUNCS];
 210 static GLuint NumExtEntryPoints = 0;
 211
 212
 213 static struct _glapi_function *
 214 get_extension_proc(const char *funcName)
 215 {
 216    GLuint i;
 217    for (i = 0; i < NumExtEntryPoints; i++) {
 218       if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
 219          return & ExtEntryTable[i];
 220       }
 221    }
 222    return NULL;
 223 }
 224
 225
 226 static GLint
 227 get_extension_proc_offset(const char *funcName)
 228 {
 229    const struct _glapi_function * const f = get_extension_proc( funcName );
 230    if (f == NULL) {
 231       return -1;
 232    }
 233
 234    return f->dispatch_offset;
 235 }
 236
 237
 238 static _glapi_proc
 239 get_extension_proc_address(const char *funcName)
 240 {
 241    const struct _glapi_function * const f = get_extension_proc( funcName );
 242    if (f == NULL) {
 243       return NULL;
 244    }
 245
 246    return f->dispatch_stub;
 247 }
 248
 249
 250 static const char *
 251 get_extension_proc_name(GLuint offset)
 252 {
 253    GLuint i;
 254    for (i = 0; i < NumExtEntryPoints; i++) {
 255       if (ExtEntryTable[i].dispatch_offset == offset) {
 256          return ExtEntryTable[i].name;
 257       }
 258    }
 259    return NULL;
 260 }
 261
 262
 263 /**
 264  * strdup() is actually not a standard ANSI C or POSIX routine.
 265  * Irix will not define it if ANSI mode is in effect.
 266  */
 267 static char *
 268 str_dup(const char *str)
 269 {
 270    char *copy;
 271    copy = (char*) malloc(strlen(str) + 1);
 272    if (!copy)
 273       return NULL;
 274    strcpy(copy, str);
 275    return copy;
 276 }
 277
 278
 279 /**
 280  * Generate new entrypoint
 281  *
 282  * Use a temporary dispatch offset of ~0 (i.e. -1).  Later, when the driver
 283  * calls \c _glapi_add_dispatch we'll put in the proper offset.  If that
 284  * never happens, and the user calls this function, he'll segfault.  That's
 285  * what you get when you try calling a GL function that doesn't really exist.
 286  *
 287  * \param funcName  Name of the function to create an entry-point for.
 288  *
 289  * \sa _glapi_add_entrypoint
 290  */
 291
 292 static struct _glapi_function *
 293 add_function_name( const char * funcName )
 294 {
 295    struct _glapi_function * entry = NULL;
 296    _glapi_proc entrypoint = NULL;
 297    char * name_dup = NULL;
 298
 299    if (NumExtEntryPoints >= MAX_EXTENSION_FUNCS)
 300       return NULL;
 301
 302    if (funcName == NULL)
 303       return NULL;
 304
 305    name_dup = str_dup(funcName);
 306    if (name_dup == NULL)
 307       return NULL;
 308
 309    entrypoint = generate_entrypoint(~0);
 310
 311    if (entrypoint == NULL) {
 312       free(name_dup);
 313       return NULL;
 314    }
 315
 316    entry = & ExtEntryTable[NumExtEntryPoints];
 317    NumExtEntryPoints++;
 318
 319    entry->name = name_dup;
 320    entry->parameter_signature = NULL;
 321    entry->dispatch_offset = ~0;
 322    entry->dispatch_stub = entrypoint;
 323
 324    return entry;
 325 }
 326
 327
 328 static struct _glapi_function *
 329 set_entry_info( struct _glapi_function * entry, const char * signature, unsigned offset )
 330 {
 331    char * sig_dup = NULL;
 332
 333    if (signature == NULL)
 334       return NULL;
 335
 336    sig_dup = str_dup(signature);
 337    if (sig_dup == NULL)
 338       return NULL;
 339
 340    fill_in_entrypoint_offset(entry->dispatch_stub, offset);
 341
 342    entry->parameter_signature = sig_dup;
 343    entry->dispatch_offset = offset;
 344
 345    return entry;
 346 }
 347
 348
 349 /**
 350  * Fill-in the dispatch stub for the named function.
 351  *
 352  * This function is intended to be called by a hardware driver.  When called,
 353  * a dispatch stub may be created created for the function.  A pointer to this
 354  * dispatch function will be returned by glXGetProcAddress.
 355  *
 356  * \param function_names       Array of pointers to function names that should
 357  *                             share a common dispatch offset.
 358  * \param parameter_signature  String representing the types of the parameters
 359  *                             passed to the named function.  Parameter types
 360  *                             are converted to characters using the following
 361  *                             rules:
 362  *                               - 'i' for \c GLint, \c GLuint, and \c GLenum
 363  *                               - 'p' for any pointer type
 364  *                               - 'f' for \c GLfloat and \c GLclampf
 365  *                               - 'd' for \c GLdouble and \c GLclampd
 366  *
 367  * \returns
 368  * The offset in the dispatch table of the named function.  A pointer to the
 369  * driver's implementation of the named function should be stored at
 370  * \c dispatch_table[\c offset].  Return -1 if error/problem.
 371  *
 372  * \sa glXGetProcAddress
 373  *
 374  * \warning
 375  * This function can only handle up to 8 names at a time.  As far as I know,
 376  * the maximum number of names ever associated with an existing GL function is
 377  * 4 (\c glPointParameterfSGIS, \c glPointParameterfEXT,
 378  * \c glPointParameterfARB, and \c glPointParameterf), so this should not be
 379  * too painful of a limitation.
 380  *
 381  * \todo
 382  * Determine whether or not \c parameter_signature should be allowed to be
 383  * \c NULL.  It doesn't seem like much of a hardship for drivers to have to
 384  * pass in an empty string.
 385  *
 386  * \todo
 387  * Determine if code should be added to reject function names that start with
 388  * 'glX'.
 389  *
 390  * \bug
 391  * Add code to compare \c parameter_signature with the parameter signature of
 392  * a static function.  In order to do that, we need to find a way to \b get
 393  * the parameter signature of a static function.
 394  */
 395
 396 PUBLIC int
 397 _glapi_add_dispatch( const char * const * function_names,
 398                      const char * parameter_signature )
 399 {
 400    static int next_dynamic_offset = _gloffset_FIRST_DYNAMIC;
 401    const char * const real_sig = (parameter_signature != NULL)
 402      ? parameter_signature : "";
 403    struct _glapi_function * entry[8];
 404    GLboolean is_static[8];
 405    unsigned i;
 406    int offset = ~0;
 407
 408
 409    (void) memset( is_static, 0, sizeof( is_static ) );
 410    (void) memset( entry, 0, sizeof( entry ) );
 411
 412    /* Find the _single_ dispatch offset for all function names that already
 413     * exist (and have a dispatch offset).
 414     */
 415
 416    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 417       const char * funcName = function_names[i];
 418       int static_offset;
 419       int extension_offset;
 420
 421       if (funcName[0] != 'g' || funcName[1] != 'l')
 422          return -1;
 423
 424       /* search built-in functions */
 425       static_offset = get_static_proc_offset(funcName);
 426
 427       if (static_offset >= 0) {
 428
 429          is_static[i] = GL_TRUE;
 430
 431          /* FIXME: Make sure the parameter signatures match!  How do we get
 432           * FIXME: the parameter signature for static functions?
 433           */
 434
 435          if ( (offset != ~0) && (static_offset != offset) ) {
 436             return -1;
 437          }
 438
 439          offset = static_offset;
 440
 441          continue;
 442       }
 443
 444       /* search added extension functions */
 445       entry[i] = get_extension_proc(funcName);
 446
 447       if (entry[i] != NULL) {
 448          extension_offset = entry[i]->dispatch_offset;
 449
 450          /* The offset may be ~0 if the function name was added by
 451           * glXGetProcAddress but never filled in by the driver.
 452           */
 453
 454          if (extension_offset == ~0) {
 455             continue;
 456          }
 457
 458          if (strcmp(real_sig, entry[i]->parameter_signature) != 0) {
 459             return -1;
 460          }
 461
 462          if ( (offset != ~0) && (extension_offset != offset) ) {
 463             return -1;
 464          }
 465
 466          offset = extension_offset;
 467       }
 468    }
 469
 470    /* If all function names are either new (or with no dispatch offset),
 471     * allocate a new dispatch offset.
 472     */
 473
 474    if (offset == ~0) {
 475       offset = next_dynamic_offset;
 476       next_dynamic_offset++;
 477    }
 478
 479    /* Fill in the dispatch offset for the new function names (and those with
 480     * no dispatch offset).
 481     */
 482
 483    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 484       if (is_static[i]) {
 485          continue;
 486       }
 487
 488       /* generate entrypoints for new function names */
 489       if (entry[i] == NULL) {
 490          entry[i] = add_function_name( function_names[i] );
 491          if (entry[i] == NULL) {
 492             /* FIXME: Possible memory leak here. */
 493             return -1;
 494          }
 495       }
 496
 497       if (entry[i]->dispatch_offset == ~0) {
 498          set_entry_info( entry[i], real_sig, offset );
 499       }
 500    }
 501
 502    return offset;
 503 }
 504
 505
 506 /**
 507  * Return offset of entrypoint for named function within dispatch table.
 508  */
 509 PUBLIC GLint
 510 _glapi_get_proc_offset(const char *funcName)
 511 {
 512    GLint offset;
 513
 514    /* search extension functions first */
 515    offset = get_extension_proc_offset(funcName);
 516    if (offset >= 0)
 517       return offset;
 518
 519    /* search static functions */
 520    return get_static_proc_offset(funcName);
 521 }
 522
 523
 524
 525 /**
 526  * Return pointer to the named function.  If the function name isn't found
 527  * in the name of static functions, try generating a new API entrypoint on
 528  * the fly with assembly language.
 529  */
 530 PUBLIC _glapi_proc
 531 _glapi_get_proc_address(const char *funcName)
 532 {
 533    _glapi_proc func;
 534    struct _glapi_function * entry;
 535
 536 #ifdef MANGLE
 537    /* skip the prefix on the name */
 538    if (funcName[1] != 'g' || funcName[2] != 'l')
 539       return NULL;
 540 #else
 541    if (funcName[0] != 'g' || funcName[1] != 'l')
 542       return NULL;
 543 #endif
 544
 545    /* search extension functions first */
 546    func = get_extension_proc_address(funcName);
 547    if (func)
 548       return func;
 549
 550    /* search static functions */
 551    func = get_static_proc_address(funcName);
 552    if (func)
 553       return func;
 554
 555    /* generate entrypoint, dispatch offset must be filled in by the driver */
 556    entry = add_function_name(funcName);
 557    if (entry == NULL)
 558       return NULL;
 559
 560    return entry->dispatch_stub;
 561 }
 562
 563
 564
 565 /**
 566  * Return the name of the function at the given dispatch offset.
 567  * This is only intended for debugging.
 568  */
 569 const char *
 570 _glapi_get_proc_name(GLuint offset)
 571 {
 572    const char * n;
 573
 574    /* search built-in functions */
 575    n = get_static_proc_name(offset);
 576    if ( n != NULL ) {
 577       return n;
 578    }
 579
 580    /* search added extension functions */
 581    return get_extension_proc_name(offset);
 582 }
 583
 584
 585
 586 /**********************************************************************
 587  * GL API table functions.
 588  */
 589
 590
 591 /*
 592  * The dispatch table size (number of entries) is the size of the
 593  * _glapi_table struct plus the number of dynamic entries we can add.
 594  * The extra slots can be filled in by DRI drivers that register new extension
 595  * functions.
 596  */
 597 #define DISPATCH_TABLE_SIZE (sizeof(struct _glapi_table) / sizeof(void *) + MAX_EXTENSION_FUNCS)
 598
 599
 600 /**
 601  * Return size of dispatch table struct as number of functions (or
 602  * slots).
 603  */
 604 PUBLIC GLuint
 605 _glapi_get_dispatch_table_size(void)
 606 {
 607    return DISPATCH_TABLE_SIZE;
 608 }
 609
 610
 611 /**
 612  * Make sure there are no NULL pointers in the given dispatch table.
 613  * Intended for debugging purposes.
 614  */
 615 void
 616 _glapi_check_table_not_null(const struct _glapi_table *table)
 617 {
 618 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
 619    const GLuint entries = _glapi_get_dispatch_table_size();
 620    const void **tab = (const void **) table;
 621    GLuint i;
 622    for (i = 1; i < entries; i++) {
 623       assert(tab[i]);
 624    }
 625 #else
 626    (void) table;
 627 #endif
 628 }
 629
 630
 631 /**
 632  * Do some spot checks to be sure that the dispatch table
 633  * slots are assigned correctly. For debugging only.
 634  */
 635 void
 636 _glapi_check_table(const struct _glapi_table *table)
 637 {
 638 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
 639    {
 640       GLuint BeginOffset = _glapi_get_proc_offset("glBegin");
 641       char *BeginFunc = (char*) &table->Begin;
 642       GLuint offset = (BeginFunc - (char *) table) / sizeof(void *);
 643       assert(BeginOffset == _gloffset_Begin);
 644       assert(BeginOffset == offset);
 645    }
 646    {
 647       GLuint viewportOffset = _glapi_get_proc_offset("glViewport");
 648       char *viewportFunc = (char*) &table->Viewport;
 649       GLuint offset = (viewportFunc - (char *) table) / sizeof(void *);
 650       assert(viewportOffset == _gloffset_Viewport);
 651       assert(viewportOffset == offset);
 652    }
 653    {
 654       GLuint VertexPointerOffset = _glapi_get_proc_offset("glVertexPointer");
 655       char *VertexPointerFunc = (char*) &table->VertexPointer;
 656       GLuint offset = (VertexPointerFunc - (char *) table) / sizeof(void *);
 657       assert(VertexPointerOffset == _gloffset_VertexPointer);
 658       assert(VertexPointerOffset == offset);
 659    }
 660    {
 661       GLuint ResetMinMaxOffset = _glapi_get_proc_offset("glResetMinmax");
 662       char *ResetMinMaxFunc = (char*) &table->ResetMinmax;
 663       GLuint offset = (ResetMinMaxFunc - (char *) table) / sizeof(void *);
 664       assert(ResetMinMaxOffset == _gloffset_ResetMinmax);
 665       assert(ResetMinMaxOffset == offset);
 666    }
 667    {
 668       GLuint blendColorOffset = _glapi_get_proc_offset("glBlendColor");
 669       char *blendColorFunc = (char*) &table->BlendColor;
 670       GLuint offset = (blendColorFunc - (char *) table) / sizeof(void *);
 671       assert(blendColorOffset == _gloffset_BlendColor);
 672       assert(blendColorOffset == offset);
 673    }
 674    {
 675       GLuint secondaryColor3fOffset = _glapi_get_proc_offset("glSecondaryColor3fEXT");
 676       char *secondaryColor3fFunc = (char*) &table->SecondaryColor3fEXT;
 677       GLuint offset = (secondaryColor3fFunc - (char *) table) / sizeof(void *);
 678       assert(secondaryColor3fOffset == _gloffset_SecondaryColor3fEXT);
 679       assert(secondaryColor3fOffset == offset);
 680    }
 681    {
 682       GLuint pointParameterivOffset = _glapi_get_proc_offset("glPointParameterivNV");
 683       char *pointParameterivFunc = (char*) &table->PointParameterivNV;
 684       GLuint offset = (pointParameterivFunc - (char *) table) / sizeof(void *);
 685       assert(pointParameterivOffset == _gloffset_PointParameterivNV);
 686       assert(pointParameterivOffset == offset);
 687    }
 688    {
 689       GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
 690       char *setFenceFunc = (char*) &table->SetFenceNV;
 691       GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
 692       assert(setFenceOffset == _gloffset_SetFenceNV);
 693       assert(setFenceOffset == offset);
 694    }
 695 #else
 696    (void) table;
 697 #endif
 698 }