prepare-struct-caller ( vregs reps return -- vregs' reps' return-vreg/f )

Vocabulary

compiler.cfg.builder.alien

Inputs

vregs	a sequence
reps	a sequence
return	a C type

Outputs

vregs'	a sequence
reps'	a sequence
return-vreg/f	a virtual register or f

Word description

Allocates an indirect structure result area when required. If struct-return-register is f, prepends the result pointer and its representation to the ordinary parameters, preserving their order. Otherwise, assigns the pointer to the dedicated result register.

Definition

USING: alien.c-types arrays classes.struct
compiler.cfg.builder.alien.params compiler.cfg.hats
cpu.architecture kernel layouts math.order namespaces sequences
;

IN: compiler.cfg.builder.alien

:: prepare-struct-caller
    ( vregs reps return -- vregs' reps' return-vreg/f )
    return large-struct? [
        return [ heap-size ] [ c-type-align cell max ] bi
        f ^^local-allot :> result struct-return-register [
            result int-rep rot 3array reg-values get push
            vregs reps
        ] [
            vregs result prefix
            reps int-rep struct-return-on-stack? f 3array prefix
        ] if* result
    ] [ vregs reps f ] if ;