kind           abiPartKind
	srcStackOffset uintptr
	dstStackOffset uintptr // used if kind == abiPartStack
	dstRegister    int     // used if kind == abiPartReg
	len            uintptr
}

func (a *abiPart) tryMerge(b abiPart) bool {
	if a.kind != abiPartStack || b.kind != abiPartStack {
		return false
	}
	if a.srcStackOffset+a.len == b.srcStackOffset && a.dstStackOffset+a.len == b.dstStackOffset {
		a.len += b.len
		return true