Function init_coverage_array

hail-fuzz/src/coverage.rs:117–127

Create a zero initialized coverage array on the heap (note: we do this instead of directly initializing the value [0; _], to avoid excess stack usage in debug mode).

()

/// Create a zero initialized coverage array on the heap (note: we do this instead of directly
/// initializing the value [0; _], to avoid excess stack usage in debug mode).
fn init_coverage_array() -> Box<[u64; MAP_SIZE / 8]> {
    let layout = std::alloc::Layout::new::<[u64; MAP_SIZE / 8]>();
    // Safety: `layout` has a non-zero size and `[u64; _]` is valid when zero initializated.
    unsafe {
        let ptr: *mut [u64; MAP_SIZE / 8] = std::alloc::alloc_zeroed(layout).cast();
        if ptr.is_null() {
            panic!("failed to allocate {} bytes for coverage array.", layout.size())
        }
        Box::from_raw(ptr)
    }
}

type EdgeCountSnapshot = Vec<u8>;