| // This is the amount of bytes that need to be left on the stack before increasing the size. |
| // It must be at least as large as the stack required by any code that does not call |
| // `ensure_sufficient_stack`. |
| const RED_ZONE: usize = 100 * 1024; // 100k |
| |
| // Only the first stack that is pushed, grows exponentially (2^n * STACK_PER_RECURSION) from then |
| // on. This flag has performance relevant characteristics. Don't set it too high. |
| const STACK_PER_RECURSION: usize = 1 * 1024 * 1024; // 1MB |
| |
| /// Grows the stack on demand to prevent stack overflow. Call this in strategic locations |
| /// to "break up" recursive calls. E.g. almost any call to `visit_expr` or equivalent can benefit |
| /// from this. |
| /// |
| /// Should not be sprinkled around carelessly, as it causes a little bit of overhead. |
| #[inline] |
| pub fn ensure_sufficient_stack<R>(f: impl FnOnce() -> R) -> R { |
| stacker::maybe_grow(RED_ZONE, STACK_PER_RECURSION, f) |
| } |
