fix 2 small bugs

cwe_checker_rs/src/abstract_domain/data.rs

@@ -161,6 +161,9 @@ impl<T: RegisterDomain> RegisterDomain for DataDomain<T> {
     fn subpiece(&self, low_byte: ByteSize, size: ByteSize) -> Self {
         if let Self::Value(value) = self {
             Self::Value(value.subpiece(low_byte, size))
+        } else if low_byte == ByteSize::new(0) && size == self.bytesize() {
+            // The operation is a no-op
+            self.clone()
         } else {
             Self::new_top(size)
         }

cwe_checker_rs/src/analysis/pointer_inference/context/trait_impls.rs

@@ -34,9 +34,9 @@ impl<'a> crate::analysis::interprocedural_fixpoint::Context<'a> for Context<'a>
 
         match &def.term {
             Def::Store { address, value } => {
-                let mut state = state.clone();
-                self.log_debug(state.handle_store(address, value), Some(&def.tid));
-                Some(state)
+                let mut new_state = state.clone();
+                self.log_debug(new_state.handle_store(address, value), Some(&def.tid));
+                Some(new_state)
             }
             Def::Assign { var, value } => {
                 let mut new_state = state.clone();

cwe_checker_rs/src/intermediate_representation/mod.rs

@@ -74,8 +74,9 @@ impl From<ByteSize> for apint::BitWidth {
 }
 
 impl From<apint::BitWidth> for ByteSize {
+    /// Convert to `ByteSize`, while always rounding up to the nearest full byte.
     fn from(bitwidth: apint::BitWidth) -> ByteSize {
-        ByteSize::new(bitwidth.to_usize() as u64 / 8)
+        ByteSize::new( (bitwidth.to_usize() + 7) as u64 / 8 )
     }
 }
 

cwe_checker_rs/src/intermediate_representation/term.rs

@@ -188,7 +188,7 @@ impl ExternSymbol {
         if self.return_values.len() == 1 {
             match self.return_values[0] {
                 Arg::Register(ref var) => Ok(var),
-                Arg::Stack { .. } => Err(anyhow!("Return value is passed on the stak")),
+                Arg::Stack { .. } => Err(anyhow!("Return value is passed on the stack")),
             }
         } else {
             Err(anyhow!("Wrong number of return values"))