From c561182f072c581fb22078dcf879f225f3020cfd Mon Sep 17 00:00:00 2001
From: Andrea Fioraldi <andreafioraldi@gmail.com>
Date: Thu, 3 Feb 2022 14:25:25 +0100
Subject: [PATCH] Set map observers initial value to T::default() on creation
 (#520)

---
 libafl/src/observers/map.rs | 41 +++++++++----------------------------
 1 file changed, 10 insertions(+), 31 deletions(-)

diff --git a/libafl/src/observers/map.rs b/libafl/src/observers/map.rs
index f9eee07fa7..9d2d1d472c 100644
--- a/libafl/src/observers/map.rs
+++ b/libafl/src/observers/map.rs
@@ -255,22 +255,20 @@ where
     /// Creates a new [`MapObserver`]
     #[must_use]
     pub fn new(name: &'static str, map: &'a mut [T]) -> Self {
-        let initial = if map.is_empty() { T::default() } else { map[0] };
         Self {
             map: OwnedSliceMut::from(map),
             name: name.to_string(),
-            initial,
+            initial: T::default(),
         }
     }
 
     /// Creates a new [`MapObserver`] with an owned map
     #[must_use]
     pub fn new_owned(name: &'static str, map: Vec<T>) -> Self {
-        let initial = if map.is_empty() { T::default() } else { map[0] };
         Self {
             map: OwnedSliceMut::from(map),
             name: name.to_string(),
-            initial,
+            initial: T::default(),
         }
     }
 
@@ -280,16 +278,10 @@ where
     /// Will dereference the owned slice with up to len elements.
     #[must_use]
     pub fn new_from_ownedref(name: &'static str, map: OwnedSliceMut<'a, T>) -> Self {
-        let map_slice = map.as_slice();
-        let initial = if map_slice.is_empty() {
-            T::default()
-        } else {
-            map_slice[0]
-        };
         Self {
             map,
             name: name.to_string(),
-            initial,
+            initial: T::default(),
         }
     }
 
@@ -298,11 +290,10 @@ where
     /// # Safety
     /// Will dereference the `map_ptr` with up to len elements.
     pub unsafe fn new_from_ptr(name: &'static str, map_ptr: *mut T, len: usize) -> Self {
-        let initial = if len > 0 { *map_ptr } else { T::default() };
         StdMapObserver {
             map: OwnedSliceMut::from_raw_parts_mut(map_ptr, len),
             name: name.to_string(),
-            initial,
+            initial: T::default(),
         }
     }
 }
@@ -447,11 +438,10 @@ where
     #[must_use]
     pub fn new(name: &'static str, map: &'a mut [T]) -> Self {
         assert!(map.len() >= N);
-        let initial = if map.is_empty() { T::default() } else { map[0] };
         Self {
             map: OwnedSliceMut::from(map),
             name: name.to_string(),
-            initial,
+            initial: T::default(),
         }
     }
 
@@ -472,11 +462,10 @@ where
     /// # Safety
     /// Will dereference the `map_ptr` with up to len elements.
     pub unsafe fn new_from_ptr(name: &'static str, map_ptr: *mut T) -> Self {
-        let initial = if N > 0 { *map_ptr } else { T::default() };
         ConstMapObserver {
             map: OwnedSliceMut::from_raw_parts_mut(map_ptr, N),
             name: name.to_string(),
-            initial,
+            initial: T::default(),
         }
     }
 }
@@ -617,12 +606,11 @@ where
 {
     /// Creates a new [`MapObserver`]
     pub fn new(name: &'static str, map: &'a mut [T], size: &'a mut usize) -> Self {
-        let initial = if map.is_empty() { T::default() } else { map[0] };
         Self {
             map: OwnedSliceMut::from(map),
             size: OwnedRefMut::Ref(size),
             name: name.into(),
-            initial,
+            initial: T::default(),
         }
     }
 
@@ -636,12 +624,11 @@ where
         max_len: usize,
         size: &'a mut usize,
     ) -> Self {
-        let initial = if max_len > 0 { *map_ptr } else { T::default() };
         VariableMapObserver {
             map: OwnedSliceMut::from_raw_parts_mut(map_ptr, max_len),
             size: OwnedRefMut::Ref(size),
             name: name.into(),
-            initial,
+            initial: T::default(),
         }
     }
 }
@@ -917,14 +904,10 @@ where
     pub fn new(name: &'static str, maps: &'a mut [&'a mut [T]]) -> Self {
         let mut idx = 0;
         let mut v = 0;
-        let mut initial = T::default();
         let mut builder = vec![];
         let maps: Vec<_> = maps
             .iter_mut()
             .map(|x| {
-                if !x.is_empty() {
-                    initial = x[0];
-                }
                 let l = x.len();
                 let r = (idx..(idx + l), v);
                 idx += l;
@@ -938,7 +921,7 @@ where
             intervals: builder.into_iter().collect::<IntervalTree<usize, usize>>(),
             len: idx,
             name: name.to_string(),
-            initial,
+            initial: T::default(),
             iter_idx: 0,
         }
     }
@@ -948,14 +931,10 @@ where
     pub fn new_owned(name: &'static str, maps: Vec<Vec<T>>) -> Self {
         let mut idx = 0;
         let mut v = 0;
-        let mut initial = T::default();
         let mut builder = vec![];
         let maps: Vec<_> = maps
             .into_iter()
             .map(|x| {
-                if !x.is_empty() {
-                    initial = x[0];
-                }
                 let l = x.len();
                 let r = (idx..(idx + l), v);
                 idx += l;
@@ -969,7 +948,7 @@ where
             intervals: builder.into_iter().collect::<IntervalTree<usize, usize>>(),
             len: idx,
             name: name.to_string(),
-            initial,
+            initial: T::default(),
             iter_idx: 0,
         }
     }