[rustc.git] / compiler / rustc_data_structures / src / stack.rs

// 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)
}
Commit	Line	Data
f9f354fc XL	1	// This is the amount of bytes that need to be left on the stack before increasing the size.
	2	// It must be at least as large as the stack required by any code that does not call
	3	// `ensure_sufficient_stack`.
	4	const RED_ZONE: usize = 100 * 1024; // 100k
	5
	6	// Only the first stack that is pushed, grows exponentially (2^n * STACK_PER_RECURSION) from then
	7	// on. This flag has performance relevant characteristics. Don't set it too high.
	8	const STACK_PER_RECURSION: usize = 1 * 1024 * 1024; // 1MB
	9
	10	/// Grows the stack on demand to prevent stack overflow. Call this in strategic locations
	11	/// to "break up" recursive calls. E.g. almost any call to `visit_expr` or equivalent can benefit
	12	/// from this.
	13	///
	14	/// Should not be sprinkled around carelessly, as it causes a little bit of overhead.
5e7ed085	15	#[inline]
f9f354fc XL	16	pub fn ensure_sufficient_stack<R>(f: impl FnOnce() -> R) -> R {
	17	stacker::maybe_grow(RED_ZONE, STACK_PER_RECURSION, f)
	18	}