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_glapi_get_proc_address() now always returns a valid dispatch stub function

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(provided we're on x86 or SPARC).  Later, _glapi_add_entrypoint() will fix-up
the dispatch offset (which was -1).  This will allow DRI libGL to avoid
probing for drivers.
This commit is contained in:
Brian Paul
2002-10-02 01:51:44 +00:00
parent a329d68903
commit 54f3aab0c7
1 changed files with 136 additions and 95 deletions
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231
src/mesa/glapi/glapi.c
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@@ -1,4 +1,4 @@
/* $Id: glapi.c,v 1.63 2002/06/29 19:48:16 brianp Exp $ */
/* $Id: glapi.c,v 1.64 2002/10/02 01:51:44 brianp Exp $ */
/*
* Mesa 3-D graphics library
@@ -43,6 +43,11 @@
* 2000/02/23 - original version for Mesa 3.3 and XFree86 4.0
* 2001/01/16 - added dispatch override feature for Mesa 3.5
* 2002/06/28 - added _glapi_set_warning_func(), Mesa 4.1.
* 2002/10/01 - _glapi_get_proc_address() will now generate new entrypoints
* itself (using offset ~0). _glapi_add_entrypoint() can be
* called afterward and it'll fill in the correct dispatch
* offset. This allows DRI libGL to avoid probing for DRI
* drivers! No changes to the public glapi interface.
*/
@@ -186,12 +191,10 @@ struct _glapi_table *_glapi_RealDispatch = (struct _glapi_table *) __glapi_noop_
void *_glapi_Context = NULL;
static GLuint MaxDispatchOffset = sizeof(struct _glapi_table) / sizeof(void *) - 1;
static GLboolean GetSizeCalled = GL_FALSE;
static GLboolean DispatchOverride = GL_FALSE;
/* strdup() is actually not a standard ANSI C or POSIX routine.
* Irix will not define it if ANSI mode is in effect.
*/
@@ -437,31 +440,6 @@ _glapi_get_override_dispatch(int layer)
}
/*
* Return size of dispatch table struct as number of functions (or
* slots).
*/
GLuint
_glapi_get_dispatch_table_size(void)
{
/* return sizeof(struct _glapi_table) / sizeof(void *);*/
GetSizeCalled = GL_TRUE;
return MaxDispatchOffset + 1;
}
/*
* Get API dispatcher version string.
*/
const char *
_glapi_get_version(void)
{
return "20020628"; /* YYYYMMDD */
}
struct name_address_offset {
const char *Name;
GLvoid *Address;
@@ -469,7 +447,7 @@ struct name_address_offset {
};
/* The code in this file is auto-generated */
/* The code in this file is auto-generated with Python */
#include "glprocs.h"
@@ -513,8 +491,20 @@ get_static_proc_address(const char *funcName)
* Extension function management.
*/
/*
* Number of extension functions which we can dynamically add at runtime.
*/
#define MAX_EXTENSION_FUNCS 300
/*
* The disptach table size (number of entries) is the sizeof 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)
#define MAX_EXTENSION_FUNCS 1000
static struct name_address_offset ExtEntryTable[MAX_EXTENSION_FUNCS];
static GLuint NumExtEntryPoints = 0;
@@ -548,7 +538,7 @@ generate_entrypoint(GLuint functionOffset)
* 14: ff a0 10 32 54 76 jmp *0x76543210(%eax)
* 14 15 16 17 18 19
*/
static const unsigned char temp[] = {
static const unsigned char insn_template[] = {
0xa1, 0x00, 0x00, 0x00, 0x00,
0x85, 0xc0,
0x74, 0x06,
@@ -556,10 +546,10 @@ generate_entrypoint(GLuint functionOffset)
0xe8, 0x00, 0x00, 0x00, 0x00,
0xff, 0xa0, 0x00, 0x00, 0x00, 0x00
};
unsigned char *code = malloc(sizeof(temp));
unsigned char *code = malloc(sizeof(insn_template));
unsigned int next_insn;
if (code) {
memcpy(code, temp, sizeof(temp));
memcpy(code, insn_template, sizeof(insn_template));
*(unsigned int *)(code + 0x01) = (unsigned int)&_glapi_Dispatch;
*(unsigned int *)(code + 0x0b) = (unsigned int)functionOffset * 4;
@@ -619,10 +609,42 @@ generate_entrypoint(GLuint functionOffset)
return code;
#else
return NULL;
#endif
#endif /* USE_*_ASM */
}
/*
* This function inserts a new dispatch offset into the assembly language
* stub that was generated with the preceeding function.
*/
static void
fill_in_entrypoint_offset(void *entrypoint, GLuint offset)
{
#if defined(USE_X86_ASM)
unsigned char *code = (unsigned char *) entrypoint;
*(unsigned int *)(code + 0x0b) = offset * 4;
*(unsigned int *)(code + 0x16) = offset * 4;
#elif defined(USE_SPARC_ASM)
/* XXX this hasn't been tested! */
unsigned int *code = (unsigned int *) entrypoint;
#ifdef __sparc_v9__
code[6] = 0x05000000; /* sethi %hi(8 * glapioffset), %g2 */
code[7] = 0x8410a000; /* or %g2, %lo(8 * glapioffset), %g2 */
code[6] |= ((offset * 8) >> 10);
code[7] |= ((offset * 8) & ((1 << 10) - 1));
__glapi_sparc_icache_flush(&code[6]);
#else /* __sparc_v9__ */
code[2] = 0xc6006000; /* ld [%g1 + %lo(4*glapioffset)], %g3 */
code[2] |= (functionOffset * 4);
__glapi_sparc_icache_flush(&code[2]);
#endif /* __sparc_v9__ */
#endif /* USE_*_ASM */
}
/*
* Add a new extension function entrypoint.
@@ -639,52 +661,54 @@ _glapi_add_entrypoint(const char *funcName, GLuint offset)
}
}
/* make sure this offset/name pair is legal (this isn't really needed) */
{
/* make sure this offset/name pair is legal */
const char *name = _glapi_get_proc_name(offset);
if (name && strcmp(name, funcName) != 0)
return GL_FALSE; /* bad name! */
}
/* See if this function has already been dynamically added */
{
/* be sure index and name match known data */
GLuint i;
for (i = 0; i < NumExtEntryPoints; i++) {
if (strcmp(ExtEntryTable[i].Name, funcName) == 0) {
/* function already registered with api */
/* function already registered */
if (ExtEntryTable[i].Offset == offset) {
return GL_TRUE; /* offsets match */
}
else if (ExtEntryTable[i].Offset == ~0
&& offset < DISPATCH_TABLE_SIZE) {
/* need to patch-up the dispatch code */
if (offset != ~0) {
fill_in_entrypoint_offset(ExtEntryTable[i].Address, offset);
ExtEntryTable[i].Offset = offset;
}
return GL_TRUE;
}
else {
return GL_FALSE; /* bad offset! */
}
}
}
/* Make sure we don't try to add a new entrypoint after someone
* has already called _glapi_get_dispatch_table_size()! If that's
* happened the caller's information would become out of date.
*/
if (GetSizeCalled)
return GL_FALSE;
/* make sure we have space */
if (NumExtEntryPoints >= MAX_EXTENSION_FUNCS) {
/* This is a new function, try to add it. */
if (NumExtEntryPoints >= MAX_EXTENSION_FUNCS ||
offset >= DISPATCH_TABLE_SIZE) {
/* No space left */
return GL_FALSE;
}
else {
void *entrypoint = generate_entrypoint(offset);
if (!entrypoint)
return GL_FALSE;
return GL_FALSE; /* couldn't generate assembly */
/* OK! */
ExtEntryTable[NumExtEntryPoints].Name = str_dup(funcName);
ExtEntryTable[NumExtEntryPoints].Offset = offset;
ExtEntryTable[NumExtEntryPoints].Address = entrypoint;
NumExtEntryPoints++;
if (offset > MaxDispatchOffset)
MaxDispatchOffset = offset;
return GL_TRUE; /* success */
}
}
@@ -694,48 +718,6 @@ _glapi_add_entrypoint(const char *funcName, GLuint offset)
}
#if 0000 /* prototype code for dynamic extension slot allocation */
static int NextFreeOffset = 409; /*XXX*/
#define MAX_DISPATCH_TABLE_SIZE 1000
/*
* Dynamically allocate a dispatch slot for an extension entrypoint
* and generate the assembly language dispatch stub.
* Return the dispatch offset for the function or -1 if no room or error.
*/
GLint
_glapi_add_entrypoint2(const char *funcName)
{
int offset;
/* first see if extension func is already known */
offset = _glapi_get_proc_offset(funcName);
if (offset >= 0)
return offset;
if (NumExtEntryPoints < MAX_EXTENSION_FUNCS
&& NextFreeOffset < MAX_DISPATCH_TABLE_SIZE) {
void *entryPoint;
offset = NextFreeOffset;
entryPoint = generate_entrypoint(offset);
if (entryPoint) {
NextFreeOffset++;
ExtEntryTable[NumExtEntryPoints].Name = str_dup(funcName);
ExtEntryTable[NumExtEntryPoints].Offset = offset;
ExtEntryTable[NumExtEntryPoints].Address = entryPoint;
NumExtEntryPoints++;
return offset;
}
}
return -1;
}
#endif
/*
* Return offset of entrypoint for named function within dispatch table.
*/
@@ -771,9 +753,35 @@ _glapi_get_proc_address(const char *funcName)
}
/* search static functions */
return get_static_proc_address(funcName);
}
{
const GLvoid *func = get_static_proc_address(funcName);
if (func)
return func;
}
/* generate new entrypoint - use a temporary dispatch offset of
* ~0 (i.e. -1). Later, when the driver calls _glapi_add_entrypoint()
* 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.
*/
if (NumExtEntryPoints < MAX_EXTENSION_FUNCS) {
GLvoid *entrypoint = generate_entrypoint(~0);
if (!entrypoint)
return GL_FALSE;
ExtEntryTable[NumExtEntryPoints].Name = str_dup(funcName);
ExtEntryTable[NumExtEntryPoints].Offset = ~0;
ExtEntryTable[NumExtEntryPoints].Address = entrypoint;
NumExtEntryPoints++;
return entrypoint;
}
else {
/* no space for new functions! */
return NULL;
}
}
@@ -786,6 +794,8 @@ _glapi_get_proc_name(GLuint offset)
{
const GLuint n = sizeof(static_functions) / sizeof(struct name_address_offset);
GLuint i;
/* search built-in functions */
for (i = 0; i < n; i++) {
if (static_functions[i].Offset == offset)
return static_functions[i].Name;
@@ -802,6 +812,29 @@ _glapi_get_proc_name(GLuint offset)
/*
* Return size of dispatch table struct as number of functions (or
* slots).
*/
GLuint
_glapi_get_dispatch_table_size(void)
{
return DISPATCH_TABLE_SIZE;
}
/*
* Get API dispatcher version string.
*/
const char *
_glapi_get_version(void)
{
return "20021001"; /* YYYYMMDD */
}
/*
* Make sure there are no NULL pointers in the given dispatch table.
* Intended for debugging purposes.
@@ -878,5 +911,13 @@ _glapi_check_table(const struct _glapi_table *table)
assert(pointParameterivOffset == offset);
assert(_glapi_get_proc_address("glPointParameterivNV") == (void *) &glPointParameterivNV);
}
{
GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
char *setFenceFunc = (char*) &table->SetFenceNV;
GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
assert(setFenceOffset == _gloffset_SetFenceNV);
assert(setFenceOffset == offset);
assert(_glapi_get_proc_address("glSetFenceNV") == (void *) &glSetFenceNV);
}
#endif
}