Given a function which calls a function, e.g.

topfun <- function(x){
   y = 1:1e6
   result <- botfun(x,y)
}

botfun <- function(x,y)  return x * sum(y)

Versus, perhaps,

topfun <- function(x){
   y = 1:1e6
   result <- botfun(x)
}

botfun <- function(x) { 
  return(x + sum(get('y',envir = parent.frame()))
}

How many copies of y are created in each case (if any)? Are there other memory or execution-time concerns? Or, for that matter, am I going at this in a naive way?