emit_library_call help

[Stephen Biggs]

On Sun, 2003-06-22 at 18:00, Stephen Biggs wrote:
> Greetings,
> 
> I am trying to unravel the many varied puzzles of emitting custom insns
> and am making progress, but am stuck on an issue:
> 
> I have an internal library function that I wish to generate an insn for
> which has the prototype:
> void bar(void *);
> 
> ... and I have a function in <machine>.c thus:
> 
> void
> foo(rtx val) /* val is possibly a pseudo-register */
> {
> 	rtx val_ptr = force_reg(Pmode,val);
> 	emit_library_call(gen_rtx_SYMBOL_REF(Pmode,"bar"),LCT_NORMAL,VOIDmode,1,val_ptr,Pmode);
> }
> 
> The argument val_ptr is created in the recognized insn as an integer
> instead of a pointer, even though I think I am forcing it to be a
> pointer. What magic is needed here to have this argument be a pointer
> argument instead of an integer argument?  Thanks for any help.
> 
> 

I also tried:
void
foo(rtx val) /* val is possibly a pseudo-register */
{
	mark_reg_pointer(val,0);
	emit_library_call(gen_rtx_SYMBOL_REF(Pmode,"bar"),LCT_NORMAL,VOIDmode,1,val,Pmode);
}
... but no soap.  How do I force this register to be a pointer register?

I finally got it to work by copying code from emit_library_call_value_1
in gcc/calls.c since I can't define FUNCTION_ARG_PASS_BY_REFERENCE in my
port, thusly:

void
foo(rtx val) /* val is possibly a pseudo-register */
{
	tree type = type_for_mode (Pmode, 0);
	rtx val_ptr,slot = gen_rtx_MEM(Pmode,
		expand_expr(build1(ADDR_EXPR,build_pointer_type(type),
			make_tree(type, val)),NULL_RTX, VOIDmode, 0));

	val_ptr = force_operand(XEXP(slot, 0),NULL_RTX);

	emit_library_call(gen_rtx_SYMBOL_REF(Pmode,"bar"),
		LCT_NORMAL,VOIDmode,1,val_ptr,Pmode);
}
 
... a gross, horrid, sleazy hack, overkill, IMHO, but I couldn't figure out any other way to do this... any suggestions?