src/mesa/glapi/glapi.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.3
   4  *
   5  * Copyright (C) 1999-2003  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 #include "glthread.h"
  58
  59 /***** BEGIN NO-OP DISPATCH *****/
  60
  61 static GLboolean WarnFlag = GL_FALSE;
  62 static _glapi_warning_func warning_func;
  63
  64 static void init_glapi_relocs(void);
  65
  66 static _glapi_proc generate_entrypoint(GLuint functionOffset);
  67 static void fill_in_entrypoint_offset(_glapi_proc entrypoint, GLuint offset);
  68
  69 /*
  70  * Enable/disable printing of warning messages.
  71  */
  72 PUBLIC void
  73 _glapi_noop_enable_warnings(GLboolean enable)
  74 {
  75    WarnFlag = enable;
  76 }
  77
  78 /*
  79  * Register a callback function for reporting errors.
  80  */
  81 PUBLIC void
  82 _glapi_set_warning_func( _glapi_warning_func func )
  83 {
  84    warning_func = func;
  85 }
  86
  87 static GLboolean
  88 warn(void)
  89 {
  90    if ((WarnFlag || getenv("MESA_DEBUG") || getenv("LIBGL_DEBUG"))
  91        && warning_func) {
  92       return GL_TRUE;
  93    }
  94    else {
  95       return GL_FALSE;
  96    }
  97 }
  98
  99
 100 #define KEYWORD1 static
 101 #define KEYWORD2 GLAPIENTRY
 102 #define NAME(func)  NoOp##func
 103
 104 #define F NULL
 105
 106 #define DISPATCH(func, args, msg)                                             \
 107    if (warn()) {                                                              \
 108       warning_func(NULL, "GL User Error: called without context: %s", #func); \
 109    }
 110
 111 #define RETURN_DISPATCH(func, args, msg)                                      \
 112    if (warn()) {                                                              \
 113       warning_func(NULL, "GL User Error: called without context: %s", #func); \
 114    }                                                                          \
 115    return 0
 116
 117 #define DISPATCH_TABLE_NAME __glapi_noop_table
 118 #define UNUSED_TABLE_NAME __unused_noop_functions
 119
 120 #define TABLE_ENTRY(name) (_glapi_proc) NoOp##name
 121
 122 static GLint NoOpUnused(void)
 123 {
 124    if (warn()) {
 125       warning_func(NULL, "GL User Error: calling extension function without a current context\n");
 126    }
 127    return 0;
 128 }
 129
 130 #include "glapitemp.h"
 131
 132 /***** END NO-OP DISPATCH *****/
 133
 134
 135
 136 /**
 137  * \name Current dispatch and current context control variables
 138  *
 139  * Depending on whether or not multithreading is support, and the type of
 140  * support available, several variables are used to store the current context
 141  * pointer and the current dispatch table pointer.  In the non-threaded case,
 142  * the variables \c _glapi_Dispatch and \c _glapi_Context are used for this
 143  * purpose.
 144  *
 145  * In the "normal" threaded case, the variables \c _glapi_Dispatch and
 146  * \c _glapi_Context will be \c NULL if an application is detected as being
 147  * multithreaded.  Single-threaded applications will use \c _glapi_Dispatch
 148  * and \c _glapi_Context just like the case without any threading support.
 149  * When \c _glapi_Dispatch and \c _glapi_Context are \c NULL, the thread state
 150  * data \c _gl_DispatchTSD and \c ContextTSD are used.  Drivers and the
 151  * static dispatch functions access these variables via \c _glapi_get_dispatch
 152  * and \c _glapi_get_context.
 153  *
 154  * There is a race condition in setting \c _glapi_Dispatch to \c NULL.  It is
 155  * possible for the original thread to be setting it at the same instant a new
 156  * thread, perhaps running on a different processor, is clearing it.  Because
 157  * of that, \c ThreadSafe, which can only ever be changed to \c GL_TRUE, is
 158  * used to determine whether or not the application is multithreaded.
 159  *
 160  * In the TLS case, the variables \c _glapi_Dispatch and \c _glapi_Context are
 161  * hardcoded to \c NULL.  Instead the TLS variables \c _glapi_tls_Dispatch and
 162  * \c _glapi_tls_Context are used.  Having \c _glapi_Dispatch and
 163  * \c _glapi_Context be hardcoded to \c NULL maintains binary compatability
 164  * between TLS enabled loaders and non-TLS DRI drivers.
 165  */
 166 /*@{*/
 167 #if defined(GLX_USE_TLS)
 168
 169 PUBLIC __thread struct _glapi_table * _glapi_tls_Dispatch
 170     __attribute__((tls_model("initial-exec")))
 171     = (struct _glapi_table *) __glapi_noop_table;
 172
 173 PUBLIC __thread void * _glapi_tls_Context
 174     __attribute__((tls_model("initial-exec")));
 175
 176 PUBLIC const struct _glapi_table *_glapi_Dispatch = NULL;
 177 PUBLIC const void *_glapi_Context = NULL;
 178
 179 #else
 180
 181 #if defined(THREADS)
 182
 183 static GLboolean ThreadSafe = GL_FALSE;  /**< In thread-safe mode? */
 184 _glthread_TSD _gl_DispatchTSD;           /**< Per-thread dispatch pointer */
 185 static _glthread_TSD ContextTSD;         /**< Per-thread context pointer */
 186
 187 #endif /* defined(THREADS) */
 188
 189 PUBLIC struct _glapi_table *_glapi_Dispatch =
 190   (struct _glapi_table *) __glapi_noop_table;
 191 PUBLIC void *_glapi_Context = NULL;
 192
 193 #endif /* defined(GLX_USE_TLS) */
 194 /*@}*/
 195
 196
 197 /**
 198  * strdup() is actually not a standard ANSI C or POSIX routine.
 199  * Irix will not define it if ANSI mode is in effect.
 200  */
 201 static char *
 202 str_dup(const char *str)
 203 {
 204    char *copy;
 205    copy = (char*) malloc(strlen(str) + 1);
 206    if (!copy)
 207       return NULL;
 208    strcpy(copy, str);
 209    return copy;
 210 }
 211
 212
 213
 214 /**
 215  * We should call this periodically from a function such as glXMakeCurrent
 216  * in order to test if multiple threads are being used.
 217  */
 218 void
 219 _glapi_check_multithread(void)
 220 {
 221 #if defined(THREADS) && !defined(GLX_USE_TLS)
 222    if (!ThreadSafe) {
 223       static unsigned long knownID;
 224       static GLboolean firstCall = GL_TRUE;
 225       if (firstCall) {
 226          knownID = _glthread_GetID();
 227          firstCall = GL_FALSE;
 228       }
 229       else if (knownID != _glthread_GetID()) {
 230          ThreadSafe = GL_TRUE;
 231          _glapi_set_dispatch(NULL);
 232       }
 233    }
 234    else if (!_glapi_get_dispatch()) {
 235       /* make sure that this thread's dispatch pointer isn't null */
 236       _glapi_set_dispatch(NULL);
 237    }
 238 #endif
 239 }
 240
 241
 242
 243 /**
 244  * Set the current context pointer for this thread.
 245  * The context pointer is an opaque type which should be cast to
 246  * void from the real context pointer type.
 247  */
 248 PUBLIC void
 249 _glapi_set_context(void *context)
 250 {
 251    (void) __unused_noop_functions; /* silence a warning */
 252 #if defined(GLX_USE_TLS)
 253    _glapi_tls_Context = context;
 254 #elif defined(THREADS)
 255    _glthread_SetTSD(&ContextTSD, context);
 256    _glapi_Context = (ThreadSafe) ? NULL : context;
 257 #else
 258    _glapi_Context = context;
 259 #endif
 260 }
 261
 262
 263
 264 /**
 265  * Get the current context pointer for this thread.
 266  * The context pointer is an opaque type which should be cast from
 267  * void to the real context pointer type.
 268  */
 269 PUBLIC void *
 270 _glapi_get_context(void)
 271 {
 272 #if defined(GLX_USE_TLS)
 273    return _glapi_tls_Context;
 274 #elif defined(THREADS)
 275    if (ThreadSafe) {
 276       return _glthread_GetTSD(&ContextTSD);
 277    }
 278    else {
 279       return _glapi_Context;
 280    }
 281 #else
 282    return _glapi_Context;
 283 #endif
 284 }
 285
 286
 287
 288 /**
 289  * Set the global or per-thread dispatch table pointer.
 290  */
 291 PUBLIC void
 292 _glapi_set_dispatch(struct _glapi_table *dispatch)
 293 {
 294 #if defined(PTHREADS) || defined(GLX_USE_TLS)
 295    static pthread_once_t once_control = PTHREAD_ONCE_INIT;
 296
 297
 298    pthread_once( & once_control, init_glapi_relocs );
 299 #endif
 300
 301    if (!dispatch) {
 302       /* use the no-op functions */
 303       dispatch = (struct _glapi_table *) __glapi_noop_table;
 304    }
 305 #ifdef DEBUG
 306    else {
 307       _glapi_check_table(dispatch);
 308    }
 309 #endif
 310
 311 #if defined(GLX_USE_TLS)
 312    _glapi_tls_Dispatch = dispatch;
 313 #elif defined(THREADS)
 314    _glthread_SetTSD(&_gl_DispatchTSD, (void *) dispatch);
 315    _glapi_Dispatch = (ThreadSafe) ? NULL : dispatch;
 316 #else /*THREADS*/
 317    _glapi_Dispatch = dispatch;
 318 #endif /*THREADS*/
 319 }
 320
 321
 322
 323 /**
 324  * Return pointer to current dispatch table for calling thread.
 325  */
 326 PUBLIC struct _glapi_table *
 327 _glapi_get_dispatch(void)
 328 {
 329    struct _glapi_table * api;
 330
 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
 341    assert( api != NULL );
 342    return api;
 343 }
 344
 345
 346 #if !defined( USE_X86_ASM )
 347 #define NEED_FUNCTION_POINTER
 348 #endif
 349
 350 /* The code in this file is auto-generated with Python */
 351 #include "glprocs.h"
 352
 353
 354 /**
 355  * Search the table of static entrypoint functions for the named function
 356  * and return the corresponding glprocs_table_t entry.
 357  */
 358 static const glprocs_table_t *
 359 find_entry( const char * n )
 360 {
 361    GLuint i;
 362
 363    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
 364       const char * test_name;
 365
 366       test_name = gl_string_table + static_functions[i].Name_offset;
 367       if (strcmp(test_name, n) == 0) {
 368          return & static_functions[i];
 369       }
 370    }
 371    return NULL;
 372 }
 373
 374
 375 /**
 376  * Return dispatch table offset of the named static (built-in) function.
 377  * Return -1 if function not found.
 378  */
 379 static GLint
 380 get_static_proc_offset(const char *funcName)
 381 {
 382    const glprocs_table_t * const f = find_entry( funcName );
 383
 384    if ( f != NULL ) {
 385       return f->Offset;
 386    }
 387    return -1;
 388 }
 389
 390
 391 #ifdef USE_X86_ASM
 392
 393 #if defined( GLX_USE_TLS )
 394 extern       GLubyte gl_dispatch_functions_start[];
 395 extern       GLubyte gl_dispatch_functions_end[];
 396 #else
 397 extern const GLubyte gl_dispatch_functions_start[];
 398 #endif
 399
 400 # if defined(THREADS) && !defined(GLX_USE_TLS)
 401 #  define X86_DISPATCH_FUNCTION_SIZE  32
 402 # else
 403 #  define X86_DISPATCH_FUNCTION_SIZE  16
 404 # endif
 405
 406
 407 /**
 408  * Return dispatch function address the named static (built-in) function.
 409  * Return NULL if function not found.
 410  */
 411 static const _glapi_proc
 412 get_static_proc_address(const char *funcName)
 413 {
 414    const glprocs_table_t * const f = find_entry( funcName );
 415
 416    if ( f != NULL ) {
 417       return (_glapi_proc) (gl_dispatch_functions_start
 418                             + (X86_DISPATCH_FUNCTION_SIZE * f->Offset));
 419    }
 420    else {
 421       return NULL;
 422    }
 423 }
 424
 425 #else
 426
 427
 428 /**
 429  * Return pointer to the named static (built-in) function.
 430  * \return  NULL if function not found.
 431  */
 432 static const _glapi_proc
 433 get_static_proc_address(const char *funcName)
 434 {
 435    const glprocs_table_t * const f = find_entry( funcName );
 436    return ( f != NULL ) ? f->Address : NULL;
 437 }
 438
 439 #endif /* USE_X86_ASM */
 440
 441
 442 /**
 443  * Return the name of the function at the given offset in the dispatch
 444  * table.  For debugging only.
 445  */
 446 static const char *
 447 get_static_proc_name( GLuint offset )
 448 {
 449    GLuint i;
 450
 451    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
 452       if (static_functions[i].Offset == offset) {
 453          return gl_string_table + static_functions[i].Name_offset;
 454       }
 455    }
 456    return NULL;
 457 }
 458
 459
 460
 461 /**********************************************************************
 462  * Extension function management.
 463  */
 464
 465 /*
 466  * Number of extension functions which we can dynamically add at runtime.
 467  */
 468 #define MAX_EXTENSION_FUNCS 300
 469
 470
 471 /*
 472  * The dispatch table size (number of entries) is the size of the
 473  * _glapi_table struct plus the number of dynamic entries we can add.
 474  * The extra slots can be filled in by DRI drivers that register new extension
 475  * functions.
 476  */
 477 #define DISPATCH_TABLE_SIZE (sizeof(struct _glapi_table) / sizeof(void *) + MAX_EXTENSION_FUNCS)
 478
 479
 480 /**
 481  * Track information about a function added to the GL API.
 482  */
 483 struct _glapi_function {
 484    /**
 485     * Name of the function.
 486     */
 487    const char * name;
 488
 489
 490    /**
 491     * Text string that describes the types of the parameters passed to the
 492     * named function.   Parameter types are converted to characters using the
 493     * following rules:
 494     *   - 'i' for \c GLint, \c GLuint, and \c GLenum
 495     *   - 'p' for any pointer type
 496     *   - 'f' for \c GLfloat and \c GLclampf
 497     *   - 'd' for \c GLdouble and \c GLclampd
 498     */
 499    const char * parameter_signature;
 500
 501
 502    /**
 503     * Offset in the dispatch table where the pointer to the real function is
 504     * located.  If the driver has not requested that the named function be
 505     * added to the dispatch table, this will have the value ~0.
 506     */
 507    unsigned dispatch_offset;
 508
 509
 510    /**
 511     * Pointer to the dispatch stub for the named function.
 512     *
 513     * \todo
 514     * The semantic of this field should be changed slightly.  Currently, it
 515     * is always expected to be non-\c NULL.  However, it would be better to
 516     * only allocate the entry-point stub when the application requests the
 517     * function via \c glXGetProcAddress.  This would save memory for all the
 518     * functions that the driver exports but that the application never wants
 519     * to call.
 520     */
 521    _glapi_proc dispatch_stub;
 522 };
 523
 524
 525 static struct _glapi_function ExtEntryTable[MAX_EXTENSION_FUNCS];
 526 static GLuint NumExtEntryPoints = 0;
 527
 528 #ifdef USE_SPARC_ASM
 529 extern void __glapi_sparc_icache_flush(unsigned int *);
 530 #endif
 531
 532 /**
 533  * Generate a dispatch function (entrypoint) which jumps through
 534  * the given slot number (offset) in the current dispatch table.
 535  * We need assembly language in order to accomplish this.
 536  */
 537 static _glapi_proc
 538 generate_entrypoint(GLuint functionOffset)
 539 {
 540 #if defined(USE_X86_ASM)
 541    /* 32 is chosen as something of a magic offset.  For x86, the dispatch
 542     * at offset 32 is the first one where the offset in the
 543     * "jmp OFFSET*4(%eax)" can't be encoded in a single byte.
 544     */
 545    const GLubyte * const template_func = gl_dispatch_functions_start
 546      + (X86_DISPATCH_FUNCTION_SIZE * 32);
 547    GLubyte * const code = (GLubyte *) malloc( X86_DISPATCH_FUNCTION_SIZE );
 548
 549
 550    if ( code != NULL ) {
 551       (void) memcpy( code, template_func, X86_DISPATCH_FUNCTION_SIZE );
 552       fill_in_entrypoint_offset( (_glapi_proc) code, functionOffset );
 553    }
 554
 555    return (_glapi_proc) code;
 556 #elif defined(USE_SPARC_ASM)
 557
 558 #ifdef __arch64__
 559    static const unsigned int insn_template[] = {
 560            0x05000000,  /* sethi        %uhi(_glapi_Dispatch), %g2      */
 561            0x03000000,  /* sethi        %hi(_glapi_Dispatch), %g1       */
 562            0x8410a000,  /* or           %g2, %ulo(_glapi_Dispatch), %g2 */
 563            0x82106000,  /* or           %g1, %lo(_glapi_Dispatch), %g1  */
 564            0x8528b020,  /* sllx         %g2, 32, %g2                    */
 565            0xc2584002,  /* ldx          [%g1 + %g2], %g1                */
 566            0x05000000,  /* sethi        %hi(8 * glapioffset), %g2       */
 567            0x8410a000,  /* or           %g2, %lo(8 * glapioffset), %g2  */
 568            0xc6584002,  /* ldx          [%g1 + %g2], %g3                */
 569            0x81c0c000,  /* jmpl         %g3, %g0                        */
 570            0x01000000   /*  nop                                         */
 571    };
 572 #else
 573    static const unsigned int insn_template[] = {
 574            0x03000000,  /* sethi        %hi(_glapi_Dispatch), %g1         */
 575            0xc2006000,  /* ld           [%g1 + %lo(_glapi_Dispatch)], %g1 */
 576            0xc6006000,  /* ld           [%g1 + %lo(4*glapioffset)], %g3   */
 577            0x81c0c000,  /* jmpl         %g3, %g0                          */
 578            0x01000000   /*  nop                                           */
 579    };
 580 #endif
 581    unsigned int *code = (unsigned int *) malloc(sizeof(insn_template));
 582    unsigned long glapi_addr = (unsigned long) &_glapi_Dispatch;
 583    if (code) {
 584       memcpy(code, insn_template, sizeof(insn_template));
 585
 586 #ifdef __arch64__
 587       code[0] |= (glapi_addr >> (32 + 10));
 588       code[1] |= ((glapi_addr & 0xffffffff) >> 10);
 589       __glapi_sparc_icache_flush(&code[0]);
 590       code[2] |= ((glapi_addr >> 32) & ((1 << 10) - 1));
 591       code[3] |= (glapi_addr & ((1 << 10) - 1));
 592       __glapi_sparc_icache_flush(&code[2]);
 593       code[6] |= ((functionOffset * 8) >> 10);
 594       code[7] |= ((functionOffset * 8) & ((1 << 10) - 1));
 595       __glapi_sparc_icache_flush(&code[6]);
 596 #else
 597       code[0] |= (glapi_addr >> 10);
 598       code[1] |= (glapi_addr & ((1 << 10) - 1));
 599       __glapi_sparc_icache_flush(&code[0]);
 600       code[2] |= (functionOffset * 4);
 601       __glapi_sparc_icache_flush(&code[2]);
 602 #endif
 603    }
 604    return (_glapi_proc) code;
 605 #else
 606    (void) functionOffset;
 607    return NULL;
 608 #endif /* USE_*_ASM */
 609 }
 610
 611
 612 /**
 613  * This function inserts a new dispatch offset into the assembly language
 614  * stub that was generated with the preceeding function.
 615  */
 616 static void
 617 fill_in_entrypoint_offset(_glapi_proc entrypoint, GLuint offset)
 618 {
 619 #if defined(USE_X86_ASM)
 620    GLubyte * const code = (GLubyte *) entrypoint;
 621
 622
 623 #if X86_DISPATCH_FUNCTION_SIZE == 32
 624    *((unsigned int *)(code + 11)) = 4 * offset;
 625    *((unsigned int *)(code + 22)) = 4 * offset;
 626 #elif X86_DISPATCH_FUNCTION_SIZE == 16 && defined( GLX_USE_TLS )
 627    *((unsigned int *)(code +  8)) = 4 * offset;
 628 #elif X86_DISPATCH_FUNCTION_SIZE == 16
 629    *((unsigned int *)(code +  7)) = 4 * offset;
 630 #else
 631 # error Invalid X86_DISPATCH_FUNCTION_SIZE!
 632 #endif
 633
 634 #elif defined(USE_SPARC_ASM)
 635
 636    /* XXX this hasn't been tested! */
 637    unsigned int *code = (unsigned int *) entrypoint;
 638 #ifdef __arch64__
 639    code[6] = 0x05000000;  /* sethi      %hi(8 * glapioffset), %g2       */
 640    code[7] = 0x8410a000;  /* or         %g2, %lo(8 * glapioffset), %g2  */
 641    code[6] |= ((offset * 8) >> 10);
 642    code[7] |= ((offset * 8) & ((1 << 10) - 1));
 643    __glapi_sparc_icache_flush(&code[6]);
 644 #else /* __arch64__ */
 645    code[2] = 0xc6006000;  /* ld         [%g1 + %lo(4*glapioffset)], %g3   */
 646    code[2] |= (offset * 4);
 647    __glapi_sparc_icache_flush(&code[2]);
 648 #endif /* __arch64__ */
 649
 650 #else
 651
 652    /* an unimplemented architecture */
 653    (void) entrypoint;
 654    (void) offset;
 655
 656 #endif /* USE_*_ASM */
 657 }
 658
 659
 660 /**
 661  * Generate new entrypoint
 662  *
 663  * Use a temporary dispatch offset of ~0 (i.e. -1).  Later, when the driver
 664  * calls \c _glapi_add_dispatch we'll put in the proper offset.  If that
 665  * never happens, and the user calls this function, he'll segfault.  That's
 666  * what you get when you try calling a GL function that doesn't really exist.
 667  *
 668  * \param funcName  Name of the function to create an entry-point for.
 669  *
 670  * \sa _glapi_add_entrypoint
 671  */
 672
 673 static struct _glapi_function *
 674 add_function_name( const char * funcName )
 675 {
 676    struct _glapi_function * entry = NULL;
 677
 678    if (NumExtEntryPoints < MAX_EXTENSION_FUNCS) {
 679       _glapi_proc entrypoint = generate_entrypoint(~0);
 680       if (entrypoint != NULL) {
 681          entry = & ExtEntryTable[NumExtEntryPoints];
 682
 683          ExtEntryTable[NumExtEntryPoints].name = str_dup(funcName);
 684          ExtEntryTable[NumExtEntryPoints].parameter_signature = NULL;
 685          ExtEntryTable[NumExtEntryPoints].dispatch_offset = ~0;
 686          ExtEntryTable[NumExtEntryPoints].dispatch_stub = entrypoint;
 687          NumExtEntryPoints++;
 688       }
 689    }
 690
 691    return entry;
 692 }
 693
 694
 695 /**
 696  * Fill-in the dispatch stub for the named function.
 697  *
 698  * This function is intended to be called by a hardware driver.  When called,
 699  * a dispatch stub may be created created for the function.  A pointer to this
 700  * dispatch function will be returned by glXGetProcAddress.
 701  *
 702  * \param function_names       Array of pointers to function names that should
 703  *                             share a common dispatch offset.
 704  * \param parameter_signature  String representing the types of the parameters
 705  *                             passed to the named function.  Parameter types
 706  *                             are converted to characters using the following
 707  *                             rules:
 708  *                               - 'i' for \c GLint, \c GLuint, and \c GLenum
 709  *                               - 'p' for any pointer type
 710  *                               - 'f' for \c GLfloat and \c GLclampf
 711  *                               - 'd' for \c GLdouble and \c GLclampd
 712  *
 713  * \returns
 714  * The offset in the dispatch table of the named function.  A pointer to the
 715  * driver's implementation of the named function should be stored at
 716  * \c dispatch_table[\c offset].
 717  *
 718  * \sa glXGetProcAddress
 719  *
 720  * \warning
 721  * This function can only handle up to 8 names at a time.  As far as I know,
 722  * the maximum number of names ever associated with an existing GL function is
 723  * 4 (\c glPointParameterfSGIS, \c glPointParameterfEXT,
 724  * \c glPointParameterfARB, and \c glPointParameterf), so this should not be
 725  * too painful of a limitation.
 726  *
 727  * \todo
 728  * Determine whether or not \c parameter_signature should be allowed to be
 729  * \c NULL.  It doesn't seem like much of a hardship for drivers to have to
 730  * pass in an empty string.
 731  *
 732  * \todo
 733  * Determine if code should be added to reject function names that start with
 734  * 'glX'.
 735  *
 736  * \bug
 737  * Add code to compare \c parameter_signature with the parameter signature of
 738  * a static function.  In order to do that, we need to find a way to \b get
 739  * the parameter signature of a static function.
 740  */
 741
 742 PUBLIC int
 743 _glapi_add_dispatch( const char * const * function_names,
 744                      const char * parameter_signature )
 745 {
 746    static int next_dynamic_offset = _gloffset_FIRST_DYNAMIC;
 747    const char * const real_sig = (parameter_signature != NULL)
 748      ? parameter_signature : "";
 749    struct _glapi_function * entry[8];
 750    GLboolean is_static[8];
 751    unsigned i;
 752    unsigned j;
 753    int offset = ~0;
 754    int new_offset;
 755
 756
 757    (void) memset( is_static, 0, sizeof( is_static ) );
 758    (void) memset( entry, 0, sizeof( entry ) );
 759
 760    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 761       /* Do some trivial validation on the name of the function.
 762        */
 763
 764 #ifdef MANGLE
 765       if (!function_names[i] || function_names[i][0] != 'm' || function_names[i][1] != 'g' || function_names[i][2] != 'l')
 766         return GL_FALSE;
 767 #else
 768       if (!function_names[i] || function_names[i][0] != 'g' || function_names[i][1] != 'l')
 769         return GL_FALSE;
 770 #endif
 771
 772
 773       /* Determine if the named function already exists.  If the function does
 774        * exist, it must have the same parameter signature as the function
 775        * being added.
 776        */
 777
 778       new_offset = get_static_proc_offset(function_names[i]);
 779       if (new_offset >= 0) {
 780          /* FIXME: Make sure the parameter signatures match!  How do we get
 781           * FIXME: the parameter signature for static functions?
 782           */
 783
 784          if ( (offset != ~0) && (new_offset != offset) ) {
 785             return -1;
 786          }
 787
 788          is_static[i] = GL_TRUE;
 789          offset = new_offset;
 790       }
 791
 792
 793       for ( j = 0 ; j < NumExtEntryPoints ; j++ ) {
 794          if (strcmp(ExtEntryTable[j].name, function_names[i]) == 0) {
 795             /* The offset may be ~0 if the function name was added by
 796              * glXGetProcAddress but never filled in by the driver.
 797              */
 798
 799             if (ExtEntryTable[j].dispatch_offset != ~0) {
 800                if (strcmp(real_sig, ExtEntryTable[j].parameter_signature)
 801                    != 0) {
 802                   return -1;
 803                }
 804
 805                if ( (offset != ~0) && (ExtEntryTable[j].dispatch_offset != offset) ) {
 806                   return -1;
 807                }
 808
 809                offset = ExtEntryTable[j].dispatch_offset;
 810             }
 811
 812             entry[i] = & ExtEntryTable[j];
 813             break;
 814          }
 815       }
 816    }
 817
 818
 819    if (offset == ~0) {
 820       offset = next_dynamic_offset;
 821       next_dynamic_offset++;
 822    }
 823
 824
 825    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 826       if (! is_static[i] ) {
 827          if (entry[i] == NULL) {
 828             entry[i] = add_function_name( function_names[i] );
 829             if (entry[i] == NULL) {
 830                /* FIXME: Possible memory leak here.
 831                 */
 832                return -1;
 833             }
 834          }
 835
 836
 837          entry[i]->parameter_signature = str_dup(real_sig);
 838          fill_in_entrypoint_offset(entry[i]->dispatch_stub, offset);
 839          entry[i]->dispatch_offset = offset;
 840       }
 841    }
 842
 843    return offset;
 844 }
 845
 846
 847 /**
 848  * Return offset of entrypoint for named function within dispatch table.
 849  */
 850 PUBLIC GLint
 851 _glapi_get_proc_offset(const char *funcName)
 852 {
 853    /* search extension functions first */
 854    GLuint i;
 855    for (i = 0; i < NumExtEntryPoints; i++) {
 856       if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
 857          return ExtEntryTable[i].dispatch_offset;
 858       }
 859    }
 860
 861    /* search static functions */
 862    return get_static_proc_offset(funcName);
 863 }
 864
 865
 866
 867 /**
 868  * Return pointer to the named function.  If the function name isn't found
 869  * in the name of static functions, try generating a new API entrypoint on
 870  * the fly with assembly language.
 871  */
 872 _glapi_proc
 873 _glapi_get_proc_address(const char *funcName)
 874 {
 875    struct _glapi_function * entry;
 876    GLuint i;
 877
 878 #ifdef MANGLE
 879    if (funcName[0] != 'm' || funcName[1] != 'g' || funcName[2] != 'l')
 880       return NULL;
 881 #else
 882    if (funcName[0] != 'g' || funcName[1] != 'l')
 883       return NULL;
 884 #endif
 885
 886    /* search extension functions first */
 887    for (i = 0; i < NumExtEntryPoints; i++) {
 888       if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
 889          return ExtEntryTable[i].dispatch_stub;
 890       }
 891    }
 892
 893    /* search static functions */
 894    {
 895       const _glapi_proc func = get_static_proc_address(funcName);
 896       if (func)
 897          return func;
 898    }
 899
 900    entry = add_function_name(funcName);
 901    return (entry == NULL) ? NULL : entry->dispatch_stub;
 902 }
 903
 904
 905
 906 /**
 907  * Return the name of the function at the given dispatch offset.
 908  * This is only intended for debugging.
 909  */
 910 const char *
 911 _glapi_get_proc_name(GLuint offset)
 912 {
 913    GLuint i;
 914    const char * n;
 915
 916    /* search built-in functions */
 917    n = get_static_proc_name(offset);
 918    if ( n != NULL ) {
 919       return n;
 920    }
 921
 922    /* search added extension functions */
 923    for (i = 0; i < NumExtEntryPoints; i++) {
 924       if (ExtEntryTable[i].dispatch_offset == offset) {
 925          return ExtEntryTable[i].name;
 926       }
 927    }
 928    return NULL;
 929 }
 930
 931
 932
 933 /**
 934  * Return size of dispatch table struct as number of functions (or
 935  * slots).
 936  */
 937 PUBLIC GLuint
 938 _glapi_get_dispatch_table_size(void)
 939 {
 940    return DISPATCH_TABLE_SIZE;
 941 }
 942
 943
 944
 945 /**
 946  * Make sure there are no NULL pointers in the given dispatch table.
 947  * Intended for debugging purposes.
 948  */
 949 void
 950 _glapi_check_table(const struct _glapi_table *table)
 951 {
 952 #ifdef DEBUG
 953    const GLuint entries = _glapi_get_dispatch_table_size();
 954    const void **tab = (const void **) table;
 955    GLuint i;
 956    for (i = 1; i < entries; i++) {
 957       assert(tab[i]);
 958    }
 959
 960    /* Do some spot checks to be sure that the dispatch table
 961     * slots are assigned correctly.
 962     */
 963    {
 964       GLuint BeginOffset = _glapi_get_proc_offset("glBegin");
 965       char *BeginFunc = (char*) &table->Begin;
 966       GLuint offset = (BeginFunc - (char *) table) / sizeof(void *);
 967       assert(BeginOffset == _gloffset_Begin);
 968       assert(BeginOffset == offset);
 969    }
 970    {
 971       GLuint viewportOffset = _glapi_get_proc_offset("glViewport");
 972       char *viewportFunc = (char*) &table->Viewport;
 973       GLuint offset = (viewportFunc - (char *) table) / sizeof(void *);
 974       assert(viewportOffset == _gloffset_Viewport);
 975       assert(viewportOffset == offset);
 976    }
 977    {
 978       GLuint VertexPointerOffset = _glapi_get_proc_offset("glVertexPointer");
 979       char *VertexPointerFunc = (char*) &table->VertexPointer;
 980       GLuint offset = (VertexPointerFunc - (char *) table) / sizeof(void *);
 981       assert(VertexPointerOffset == _gloffset_VertexPointer);
 982       assert(VertexPointerOffset == offset);
 983    }
 984    {
 985       GLuint ResetMinMaxOffset = _glapi_get_proc_offset("glResetMinmax");
 986       char *ResetMinMaxFunc = (char*) &table->ResetMinmax;
 987       GLuint offset = (ResetMinMaxFunc - (char *) table) / sizeof(void *);
 988       assert(ResetMinMaxOffset == _gloffset_ResetMinmax);
 989       assert(ResetMinMaxOffset == offset);
 990    }
 991    {
 992       GLuint blendColorOffset = _glapi_get_proc_offset("glBlendColor");
 993       char *blendColorFunc = (char*) &table->BlendColor;
 994       GLuint offset = (blendColorFunc - (char *) table) / sizeof(void *);
 995       assert(blendColorOffset == _gloffset_BlendColor);
 996       assert(blendColorOffset == offset);
 997    }
 998    {
 999       GLuint istextureOffset = _glapi_get_proc_offset("glIsTextureEXT");
1000       char *istextureFunc = (char*) &table->IsTextureEXT;
1001       GLuint offset = (istextureFunc - (char *) table) / sizeof(void *);
1002       assert(istextureOffset == _gloffset_IsTextureEXT);
1003       assert(istextureOffset == offset);
1004    }
1005    {
1006       GLuint secondaryColor3fOffset = _glapi_get_proc_offset("glSecondaryColor3fEXT");
1007       char *secondaryColor3fFunc = (char*) &table->SecondaryColor3fEXT;
1008       GLuint offset = (secondaryColor3fFunc - (char *) table) / sizeof(void *);
1009       assert(secondaryColor3fOffset == _gloffset_SecondaryColor3fEXT);
1010       assert(secondaryColor3fOffset == offset);
1011       assert(_glapi_get_proc_address("glSecondaryColor3fEXT") == (_glapi_proc) &glSecondaryColor3fEXT);
1012    }
1013    {
1014       GLuint pointParameterivOffset = _glapi_get_proc_offset("glPointParameterivNV");
1015       char *pointParameterivFunc = (char*) &table->PointParameterivNV;
1016       GLuint offset = (pointParameterivFunc - (char *) table) / sizeof(void *);
1017       assert(pointParameterivOffset == _gloffset_PointParameterivNV);
1018       assert(pointParameterivOffset == offset);
1019       assert(_glapi_get_proc_address("glPointParameterivNV") == (_glapi_proc) &glPointParameterivNV);
1020    }
1021    {
1022       GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
1023       char *setFenceFunc = (char*) &table->SetFenceNV;
1024       GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
1025       assert(setFenceOffset == _gloffset_SetFenceNV);
1026       assert(setFenceOffset == offset);
1027       assert(_glapi_get_proc_address("glSetFenceNV") == (_glapi_proc) &glSetFenceNV);
1028    }
1029 #else
1030    (void) table;
1031 #endif
1032 }
1033
1034
1035 /**
1036  * Perform platform-specific GL API entry-point fixups.
1037  *
1038  *
1039  */
1040 static void
1041 init_glapi_relocs( void )
1042 {
1043 #if defined( USE_X86_ASM ) && defined( GLX_USE_TLS )
1044     extern void * _x86_get_dispatch(void);
1045     const GLubyte * const get_disp = (const GLubyte *) _x86_get_dispatch;
1046     GLubyte * curr_func = (GLubyte *) gl_dispatch_functions_start;
1047
1048
1049     while ( curr_func != (GLubyte *) gl_dispatch_functions_end ) {
1050         (void) memcpy( curr_func, get_disp, 6 );
1051         curr_func += X86_DISPATCH_FUNCTION_SIZE;
1052     }
1053 #endif /* defined( USE_X86_ASM ) && defined( GLX_USE_TLS ) */
1054 }