Greetings!
OK, I believe at long last I have a fix, but I'd like to make sure it
is not accidental, i.e. possibly vanishing with future ia64 toolchain
development.
Andreas Schwab <[EMAIL PROTECTED]> writes:
> [removing emacs-devel from cc: since it's off-topic there.]
>
> Camm Maguire <[EMAIL PROTECTED]> writes:
>
> > Far better than trying to probe ld.so's function descriptor table, I
> > should rather ammend the lisp compiler to write a static function
> > structure into each produced C source file before compilation, with the
> > structure's pointer element statically initialized to the static
> > function in the same file. I then use the address for this structure at
> > runtime in setting the lisp symbol's function definition. This should
> > work, right?
>
> I have rechecked the specs, and actually the key point isn't static
> vs. dynamic assignment, but rather local vs. dynamic symbols. A function
> descriptor for a symbol in a shared library will be allocated by the
> dynamic linker, whereas those for symbols in the executable are allocated
> by the static linker. So you only have to make sure that all function
> pointers in the executable only refer to functions therein.
>
When I first read this, I was more confused by the meaning of the term
'local' and what I've been seeing. Briefly I have two possible
recourses, both of which are employed in the present fix:
1) If the function is static, and this static address is dynamically
loaded into a structure at runtime, all is well -- the address
stored and used is outside of ld.so's memory map:
static void foo () {}
void
bar_init () {
make_lisp_function("FOO",foo);
}
2) If the function is not static, then its address must be assigned
to a static variable initialized at compile time:
void foo() {}
void
bar_init() {
{
static lisp_function_body f={....,foo,....}
make_lisp_function_from_body("FOO",&f);
}
}
I.e. functions 'local' to the program but visible between C source
files still go through dynamic function generation in ld.so.
This has the distinct disadvantage that the body of the function is
not handled by the main memory management system/gbc.
I suppose the right thing to do is to write static stubs for all
functions.
Advise/comments most welcome.
Take care,
> Andreas.
>
> --
> Andreas Schwab, SuSE Labs, [EMAIL PROTECTED]
> SuSE Linux AG, Deutschherrnstr. 15-19, D-90429 Nürnberg
> Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
> "And now for something completely different."
>
>
>
--
Camm Maguire [EMAIL PROTECTED]
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