Switched from StdMapObserve to ConstMapObserver to create observer

Also updated signals_set to directly modify SIGNALS array

fuzzers/fuzz_anything/baby_no_std/src/main.rs

@@ -8,7 +8,6 @@ extern crate alloc;
 use alloc::ffi::CString;
 #[cfg(not(any(windows)))]
 use core::panic::PanicInfo;
-use core::ptr::write;
 
 use libafl::{
     corpus::InMemoryCorpus,
@@ -20,12 +19,12 @@ use libafl::{
     inputs::{BytesInput, HasTargetBytes},
     monitors::SimpleMonitor,
     mutators::{havoc_mutations::havoc_mutations, scheduled::StdScheduledMutator},
-    observers::StdMapObserver,
+    observers::ConstMapObserver,
     schedulers::QueueScheduler,
     stages::mutational::StdMutationalStage,
     state::StdState,
 };
-use libafl_bolts::{nonzero, rands::StdRand, tuples::tuple_list, AsSlice};
+use libafl_bolts::{nonnull_raw_mut, nonzero, rands::StdRand, tuples::tuple_list, AsSlice};
 #[cfg(any(windows, unix))]
 use libc::{abort, printf};
 use static_alloc::Bump;
@@ -48,12 +47,10 @@ fn panic(_info: &PanicInfo) -> ! {
 
 /// Coverage map with explicit assignments due to the lack of instrumentation
 static mut SIGNALS: [u8; 16] = [0; 16];
-#[allow(static_mut_refs)]
-static mut SIGNALS_PTR: *mut u8 = unsafe { SIGNALS.as_mut_ptr() };
 
 /// Assign a signal to the signals map
 fn signals_set(idx: usize) {
-    unsafe { write(SIGNALS_PTR.add(idx), 1) };
+    unsafe { SIGNALS[idx] = 1 };
 }
 
 /// Provide custom time in `no_std` environment
@@ -89,9 +86,7 @@ pub extern "C" fn main(_argc: isize, _argv: *const *const u8) -> isize {
     };
 
     // Create an observation channel using the signals map
-    #[allow(static_mut_refs)]
-    let observer = unsafe { StdMapObserver::from_mut_ptr("signals", SIGNALS_PTR, SIGNALS.len()) };
-
+    let observer = unsafe { ConstMapObserver::from_mut_ptr("signals", nonnull_raw_mut!(SIGNALS)) };
     // Feedback to rate the interestingness of an input
     let mut feedback = MaxMapFeedback::new(&observer);