Tail Calls

Select Connection: INPUT[inlineListSuggester(optionQuery(#permanent_note), optionQuery(#literature_note), optionQuery(#fleeting_note)):connections]

DEFINITION

Any function that is in the tail position, meaning the final action be be performed before a function returns

Without Tail Call Optimization (TCO) the callee $g()$ returns back to the caller $f()$ and creates a new stack frame and pushes the return address.

With TCO enables, instead of a call instruction the compiler emits a jmp. $g()$ returns directly to whatever function called $f()$, as if it were part of the same function.

What it does:

• reduces stack memory from $O(n)$ to $O(1)$ when making $n$ consecutive tail calls. Reduces stack overflow occurences
• call has more performance overhead than jmp

Based on a paper: https://dspace.mit.edu/handle/1721.1/5753

The problem is that it’s not guaranteed, so the compiler can go back to an actual call.