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xserver/glx/glapi.c

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/*
* Mesa 3-D graphics library
* Version: 6.5
*
* Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* This file manages the OpenGL API dispatch layer. There are functions
* to set/get the current dispatch table for the current thread and to
* manage registration/dispatch of dynamically added extension functions.
*
* This code was originally general enough to be shared with Mesa, but
* they diverged long ago, so this is now just enough support to make
* indirect GLX work.
*/
#include <dix-config.h>
#include <X11/Xfuncproto.h>
#include <os.h>
#define PUBLIC _X_EXPORT
#include <stdlib.h>
#include <string.h>
#ifdef DEBUG
#include <assert.h>
#endif
#include "glapi.h"
#include "dispatch.h"
#include "glapitable.h"
#define FIRST_DYNAMIC_OFFSET (sizeof(struct _glapi_table) / sizeof(void *))
#if defined(PTHREADS) || defined(GLX_USE_TLS)
static void init_glapi_relocs(void);
#endif
/**
* \name Current dispatch and current context control variables
*
* Depending on whether or not multithreading is support, and the type of
* support available, several variables are used to store the current context
* pointer and the current dispatch table pointer. In the non-threaded case,
* the variables \c _glapi_Dispatch and \c _glapi_Context are used for this
* purpose.
*
* In the "normal" threaded case, the variables \c _glapi_Dispatch and
* \c _glapi_Context will be \c NULL if an application is detected as being
* multithreaded. Single-threaded applications will use \c _glapi_Dispatch
* and \c _glapi_Context just like the case without any threading support.
* When \c _glapi_Dispatch and \c _glapi_Context are \c NULL, the thread state
* data \c _gl_DispatchTSD and \c ContextTSD are used. Drivers and the
* static dispatch functions access these variables via \c _glapi_get_dispatch
* and \c _glapi_get_context.
*
* In the TLS case, the variables \c _glapi_Dispatch and \c _glapi_Context are
* hardcoded to \c NULL. Instead the TLS variables \c _glapi_tls_Dispatch and
* \c _glapi_tls_Context are used. Having \c _glapi_Dispatch and
* \c _glapi_Context be hardcoded to \c NULL maintains binary compatability
* between TLS enabled loaders and non-TLS DRI drivers.
*/
/*@{*/
#if defined(GLX_USE_TLS)
PUBLIC TLS struct _glapi_table *_glapi_tls_Dispatch = NULL;
PUBLIC TLS void *_glapi_tls_Context;
PUBLIC const struct _glapi_table *_glapi_Dispatch = NULL;
PUBLIC const void *_glapi_Context = NULL;
#else
#if defined(THREADS)
_glthread_TSD _gl_DispatchTSD; /**< Per-thread dispatch pointer */
static _glthread_TSD ContextTSD; /**< Per-thread context pointer */
#if defined(WIN32_THREADS)
void FreeTSD(_glthread_TSD * p);
void
FreeAllTSD(void)
{
FreeTSD(&_gl_DispatchTSD);
FreeTSD(&ContextTSD);
}
#endif /* defined(WIN32_THREADS) */
#endif /* defined(THREADS) */
PUBLIC struct _glapi_table *_glapi_Dispatch = NULL;
PUBLIC void *_glapi_Context = NULL;
#endif /* defined(GLX_USE_TLS) */
/*@}*/
/*
* xserver's gl is not multithreaded, we promise.
*/
PUBLIC void
_glapi_check_multithread(void)
{
}
/**
* Set the current context pointer for this thread.
* The context pointer is an opaque type which should be cast to
* void from the real context pointer type.
*/
PUBLIC void
_glapi_set_context(void *context)
{
#if defined(GLX_USE_TLS)
_glapi_tls_Context = context;
#elif defined(THREADS)
_glthread_SetTSD(&ContextTSD, context);
_glapi_Context = context;
#else
_glapi_Context = context;
#endif
}
/**
* Get the current context pointer for this thread.
* The context pointer is an opaque type which should be cast from
* void to the real context pointer type.
*/
PUBLIC void *
_glapi_get_context(void)
{
#if defined(GLX_USE_TLS)
return _glapi_tls_Context;
#else
return _glapi_Context;
#endif
}
/**
* Set the global or per-thread dispatch table pointer.
*/
PUBLIC void
_glapi_set_dispatch(struct _glapi_table *dispatch)
{
#if defined(PTHREADS) || defined(GLX_USE_TLS)
static pthread_once_t once_control = PTHREAD_ONCE_INIT;
pthread_once(&once_control, init_glapi_relocs);
#endif
#if defined(GLX_USE_TLS)
_glapi_tls_Dispatch = dispatch;
#elif defined(THREADS)
_glthread_SetTSD(&_gl_DispatchTSD, (void *) dispatch);
_glapi_Dispatch = dispatch;
#else /*THREADS*/
_glapi_Dispatch = dispatch;
#endif /*THREADS*/
}
/**
* Return pointer to current dispatch table for calling thread.
*/
PUBLIC struct _glapi_table *
_glapi_get_dispatch(void)
{
struct _glapi_table *api;
#if defined(GLX_USE_TLS)
api = _glapi_tls_Dispatch;
#else
api = _glapi_Dispatch;
#endif
return api;
}
/***
*** The rest of this file is pretty much concerned with GetProcAddress
*** functionality.
***/
#if defined(USE_X64_64_ASM) && defined(GLX_USE_TLS)
#define DISPATCH_FUNCTION_SIZE 16
#elif defined(USE_X86_ASM)
#if defined(THREADS) && !defined(GLX_USE_TLS)
#define DISPATCH_FUNCTION_SIZE 32
#else
#define DISPATCH_FUNCTION_SIZE 16
#endif
#endif
/* The code in this file is auto-generated with Python */
#include "glprocs.h"
/**
* Search the table of static entrypoint functions for the named function
* and return the corresponding glprocs_table_t entry.
*/
static const glprocs_table_t *
find_entry(const char *n)
{
GLuint i;
for (i = 0; static_functions[i].Name_offset >= 0; i++) {
const char *testName =
gl_string_table + static_functions[i].Name_offset;
if (strcmp(testName, n) == 0) {
return &static_functions[i];
}
}
return NULL;
}
/**
* Return dispatch table offset of the named static (built-in) function.
* Return -1 if function not found.
*/
static GLint
get_static_proc_offset(const char *funcName)
{
const glprocs_table_t *const f = find_entry(funcName);
if (f) {
return f->Offset;
}
return -1;
}
/**********************************************************************
* Extension function management.
*/
/*
* Number of extension functions which we can dynamically add at runtime.
*/
#define MAX_EXTENSION_FUNCS 300
/*
* The dispatch table size (number of entries) is the size of the
* _glapi_table struct plus the number of dynamic entries we can add.
* The extra slots can be filled in by DRI drivers that register new extension
* functions.
*/
#define DISPATCH_TABLE_SIZE (sizeof(struct _glapi_table) / sizeof(void *) + MAX_EXTENSION_FUNCS)
/**
* Track information about a function added to the GL API.
*/
struct _glapi_function {
/**
* Name of the function.
*/
const char *name;
/**
* Text string that describes the types of the parameters passed to the
* named function. Parameter types are converted to characters using the
* following rules:
* - 'i' for \c GLint, \c GLuint, and \c GLenum
* - 'p' for any pointer type
* - 'f' for \c GLfloat and \c GLclampf
* - 'd' for \c GLdouble and \c GLclampd
*/
const char *parameter_signature;
/**
* Offset in the dispatch table where the pointer to the real function is
* located. If the driver has not requested that the named function be
* added to the dispatch table, this will have the value ~0.
*/
unsigned dispatch_offset;
};
static struct _glapi_function ExtEntryTable[MAX_EXTENSION_FUNCS];
static GLuint NumExtEntryPoints = 0;
/**
* Generate new entrypoint
*
* Use a temporary dispatch offset of ~0 (i.e. -1). Later, when the driver
* calls \c _glapi_add_dispatch we'll put in the proper offset. If that
* never happens, and the user calls this function, he'll segfault. That's
* what you get when you try calling a GL function that doesn't really exist.
*
* \param funcName Name of the function to create an entry-point for.
*
* \sa _glapi_add_entrypoint
*/
static struct _glapi_function *
add_function_name(const char *funcName)
{
struct _glapi_function *entry = NULL;
if (NumExtEntryPoints < MAX_EXTENSION_FUNCS) {
entry = &ExtEntryTable[NumExtEntryPoints];
ExtEntryTable[NumExtEntryPoints].name = strdup(funcName);
ExtEntryTable[NumExtEntryPoints].parameter_signature = NULL;
ExtEntryTable[NumExtEntryPoints].dispatch_offset = ~0;
NumExtEntryPoints++;
}
return entry;
}
/**
* Fill-in the dispatch stub for the named function.
*
* This function is intended to be called by a hardware driver. When called,
* a dispatch stub may be created created for the function. A pointer to this
* dispatch function will be returned by glXGetProcAddress.
*
* \param function_names Array of pointers to function names that should
* share a common dispatch offset.
* \param parameter_signature String representing the types of the parameters
* passed to the named function. Parameter types
* are converted to characters using the following
* rules:
* - 'i' for \c GLint, \c GLuint, and \c GLenum
* - 'p' for any pointer type
* - 'f' for \c GLfloat and \c GLclampf
* - 'd' for \c GLdouble and \c GLclampd
*
* \returns
* The offset in the dispatch table of the named function. A pointer to the
* driver's implementation of the named function should be stored at
* \c dispatch_table[\c offset].
*
* \sa glXGetProcAddress
*
* \warning
* This function can only handle up to 8 names at a time. As far as I know,
* the maximum number of names ever associated with an existing GL function is
* 4 (\c glPointParameterfSGIS, \c glPointParameterfEXT,
* \c glPointParameterfARB, and \c glPointParameterf), so this should not be
* too painful of a limitation.
*
* \todo
* Determine whether or not \c parameter_signature should be allowed to be
* \c NULL. It doesn't seem like much of a hardship for drivers to have to
* pass in an empty string.
*
* \todo
* Determine if code should be added to reject function names that start with
* 'glX'.
*
* \bug
* Add code to compare \c parameter_signature with the parameter signature of
* a static function. In order to do that, we need to find a way to \b get
* the parameter signature of a static function.
*/
PUBLIC int
_glapi_add_dispatch(const char *const *function_names,
const char *parameter_signature)
{
static int next_dynamic_offset = FIRST_DYNAMIC_OFFSET;
const char *const real_sig = (parameter_signature != NULL)
? parameter_signature : "";
struct _glapi_function *entry[8];
GLboolean is_static[8];
unsigned i;
unsigned j;
int offset = ~0;
int new_offset;
(void) memset(is_static, 0, sizeof(is_static));
(void) memset(entry, 0, sizeof(entry));
for (i = 0; function_names[i] != NULL; i++) {
/* Do some trivial validation on the name of the function. */
if (function_names[i][0] != 'g' || function_names[i][1] != 'l')
return GL_FALSE;
/* Determine if the named function already exists. If the function does
* exist, it must have the same parameter signature as the function
* being added.
*/
new_offset = get_static_proc_offset(function_names[i]);
if (new_offset >= 0) {
/* FIXME: Make sure the parameter signatures match! How do we get
* FIXME: the parameter signature for static functions?
*/
if ((offset != ~0) && (new_offset != offset)) {
return -1;
}
is_static[i] = GL_TRUE;
offset = new_offset;
}
for (j = 0; j < NumExtEntryPoints; j++) {
if (strcmp(ExtEntryTable[j].name, function_names[i]) == 0) {
/* The offset may be ~0 if the function name was added by
* glXGetProcAddress but never filled in by the driver.
*/
if (ExtEntryTable[j].dispatch_offset != ~0) {
if (strcmp(real_sig, ExtEntryTable[j].parameter_signature)
!= 0)
return -1;
if ((offset != ~0) &&
(ExtEntryTable[j].dispatch_offset != offset)) {
return -1;
}
offset = ExtEntryTable[j].dispatch_offset;
}
entry[i] = &ExtEntryTable[j];
break;
}
}
}
if (offset == ~0) {
offset = next_dynamic_offset;
next_dynamic_offset++;
}
for (i = 0; function_names[i] != NULL; i++) {
if (!is_static[i]) {
if (entry[i] == NULL) {
entry[i] = add_function_name(function_names[i]);
if (entry[i] == NULL)
return -1;
}
entry[i]->parameter_signature = strdup(real_sig);
entry[i]->dispatch_offset = offset;
}
}
return offset;
}
/*
* glXGetProcAddress doesn't exist in the protocol, the drivers never call
* this themselves, and neither does the server. warn if it happens though.
*/
PUBLIC _glapi_proc
_glapi_get_proc_address(const char *funcName)
{
ErrorF("_glapi_get_proc_address called!\n");
return NULL;
}
/**
* Return size of dispatch table struct as number of functions (or
* slots).
*/
PUBLIC GLuint
_glapi_get_dispatch_table_size(void)
{
return DISPATCH_TABLE_SIZE;
}
#if defined(PTHREADS) || defined(GLX_USE_TLS)
/**
* Perform platform-specific GL API entry-point fixups.
*/
static void
init_glapi_relocs(void)
{
#if defined(USE_X86_ASM) && defined(GLX_USE_TLS) && !defined(GLX_X86_READONLY_TEXT)
extern unsigned long _x86_get_dispatch(void);
char run_time_patch[] = {
0x65, 0xa1, 0, 0, 0, 0 /* movl %gs:0,%eax */
};
GLuint *offset = (GLuint *) &run_time_patch[2]; /* 32-bits for x86/32 */
const GLubyte *const get_disp = (const GLubyte *) run_time_patch;
GLubyte *curr_func = (GLubyte *) gl_dispatch_functions_start;
*offset = _x86_get_dispatch();
while (curr_func != (GLubyte *) gl_dispatch_functions_end) {
(void) memcpy(curr_func, get_disp, sizeof(run_time_patch));
curr_func += DISPATCH_FUNCTION_SIZE;
}
#endif
}
#endif /* defined(PTHREADS) || defined(GLX_USE_TLS) */
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