Use conditional branches to restrict value sets of variables (#159)

src/cwe_checker_lib/src/abstract_domain/data.rs

 use super::{
     AbstractDomain, AbstractIdentifier, HasTop, Interval, PointerDomain, RegisterDomain,
-    SizedDomain, TryToBitvec, TryToInterval,
+    SizedDomain, SpecializeByConditional, TryToBitvec, TryToInterval,
 };
 use crate::intermediate_representation::*;
 use crate::prelude::*;
@@ -68,6 +68,48 @@ impl<T: RegisterDomain> DataDomain<T> {
     }
 }
 
+impl<T: SpecializeByConditional + RegisterDomain> SpecializeByConditional for DataDomain<T> {
+    fn add_signed_less_equal_bound(self, bound: &Bitvector) -> Result<Self, Error> {
+        if let Self::Value(value) = self {
+            Ok(Self::Value(value.add_signed_less_equal_bound(bound)?))
+        } else {
+            Ok(self)
+        }
+    }
+
+    fn add_unsigned_less_equal_bound(self, bound: &Bitvector) -> Result<Self, Error> {
+        if let Self::Value(value) = self {
+            Ok(Self::Value(value.add_unsigned_less_equal_bound(bound)?))
+        } else {
+            Ok(self)
+        }
+    }
+
+    fn add_signed_greater_equal_bound(self, bound: &Bitvector) -> Result<Self, Error> {
+        if let Self::Value(value) = self {
+            Ok(Self::Value(value.add_signed_greater_equal_bound(bound)?))
+        } else {
+            Ok(self)
+        }
+    }
+
+    fn add_unsigned_greater_equal_bound(self, bound: &Bitvector) -> Result<Self, Error> {
+        if let Self::Value(value) = self {
+            Ok(Self::Value(value.add_unsigned_greater_equal_bound(bound)?))
+        } else {
+            Ok(self)
+        }
+    }
+
+    fn add_not_equal_bound(self, bound: &Bitvector) -> Result<Self, Error> {
+        if let Self::Value(value) = self {
+            Ok(Self::Value(value.add_not_equal_bound(bound)?))
+        } else {
+            Ok(self)
+        }
+    }
+}
+
 impl<T: RegisterDomain> SizedDomain for DataDomain<T> {
     // Return the bitsize of `self`.
     fn bytesize(&self) -> ByteSize {
@@ -244,6 +286,22 @@ impl<T: RegisterDomain + TryToInterval> TryToInterval for DataDomain<T> {
     }
 }
 
+impl<T: RegisterDomain> std::ops::Add for DataDomain<T> {
+    type Output = DataDomain<T>;
+
+    fn add(self, rhs: Self) -> Self {
+        self.bin_op(BinOpType::IntAdd, &rhs)
+    }
+}
+
+impl<T: RegisterDomain> std::ops::Sub for DataDomain<T> {
+    type Output = DataDomain<T>;
+
+    fn sub(self, rhs: Self) -> Self {
+        self.bin_op(BinOpType::IntSub, &rhs)
+    }
+}
+
 impl<T: RegisterDomain + Display> DataDomain<T> {
     /// Get a more compact json-representation of the data domain.
     /// Intended for pretty printing, not useable for serialization/deserialization.

src/cwe_checker_lib/src/abstract_domain/interval.rs

@@ -3,7 +3,7 @@ use std::fmt::Display;
 use crate::intermediate_representation::*;
 use crate::prelude::*;
 
-use super::{AbstractDomain, HasTop, RegisterDomain, SizedDomain};
+use super::{AbstractDomain, HasTop, RegisterDomain, SizedDomain, SpecializeByConditional};
 use super::{TryToBitvec, TryToInterval};
 
 mod simple_interval;
@@ -217,6 +217,113 @@ impl IntervalDomain {
                 .map(|bitvec| bitvec.into_sign_extend(width).unwrap()),
         }
     }
+
+    /// Compute the intersection of two intervals.
+    /// Return an error if the intersection is empty.
+    pub fn intersect(&self, other: &Self) -> Result<Self, Error> {
+        let mut intersected_domain: IntervalDomain =
+            self.interval.signed_intersect(&other.interval)?.into();
+        intersected_domain.update_widening_lower_bound(&self.widening_lower_bound);
+        intersected_domain.update_widening_lower_bound(&other.widening_lower_bound);
+        intersected_domain.update_widening_upper_bound(&self.widening_upper_bound);
+        intersected_domain.update_widening_upper_bound(&other.widening_upper_bound);
+        Ok(intersected_domain)
+    }
+}
+
+impl SpecializeByConditional for IntervalDomain {
+    fn add_signed_less_equal_bound(mut self, bound: &Bitvector) -> Result<Self, Error> {
+        if let Some(old_upper_bound) = &self.widening_upper_bound {
+            if old_upper_bound.checked_sle(bound).unwrap() {
+                return Ok(self);
+            } else if self.interval.end.checked_slt(bound).unwrap() {
+                self.widening_upper_bound = Some(bound.clone());
+                return Ok(self);
+            } else {
+                self.widening_upper_bound = None;
+            }
+        } else if self.interval.end.checked_slt(bound).unwrap() {
+            self.widening_upper_bound = Some(bound.clone());
+            return Ok(self);
+        }
+        // we already know that the bound is less equal to `self.interval.end`
+        if self.interval.start.checked_sle(bound).unwrap() {
+            self.interval.end = bound.clone();
+            Ok(self)
+        } else {
+            Err(anyhow!("Empty interval"))
+        }
+    }
+
+    fn add_signed_greater_equal_bound(mut self, bound: &Bitvector) -> Result<Self, Error> {
+        if let Some(old_lower_bound) = &self.widening_lower_bound {
+            if old_lower_bound.checked_sge(bound).unwrap() {
+                return Ok(self);
+            } else if self.interval.start.checked_sgt(bound).unwrap() {
+                self.widening_lower_bound = Some(bound.clone());
+                return Ok(self);
+            } else {
+                self.widening_lower_bound = None;
+            }
+        } else if self.interval.start.checked_sgt(bound).unwrap() {
+            self.widening_lower_bound = Some(bound.clone());
+            return Ok(self);
+        }
+        // we already know that the bound is greater equal to `self.interval.start`
+        if self.interval.end.checked_sge(bound).unwrap() {
+            self.interval.start = bound.clone();
+            Ok(self)
+        } else {
+            Err(anyhow!("Empty interval"))
+        }
+    }
+
+    fn add_unsigned_less_equal_bound(mut self, bound: &Bitvector) -> Result<Self, Error> {
+        if bound.sign_bit().to_bool() {
+            if self.interval.end.sign_bit().to_bool() {
+                self.add_signed_less_equal_bound(bound)
+            } else if self.interval.start.sign_bit().to_bool() {
+                Ok(self)
+            } else {
+                self.add_signed_greater_equal_bound(&Bitvector::zero(bound.width()))
+            }
+        } else {
+            self = self.add_signed_greater_equal_bound(&Bitvector::zero(bound.width()))?;
+            self.add_signed_less_equal_bound(bound)
+        }
+    }
+
+    fn add_unsigned_greater_equal_bound(mut self, bound: &Bitvector) -> Result<Self, Error> {
+        if bound.sign_bit().to_bool() {
+            self = self.add_signed_less_equal_bound(&(-Bitvector::one(bound.width())))?;
+            self.add_signed_greater_equal_bound(bound)
+        } else if self.interval.end.checked_slt(bound).unwrap() {
+            self.add_signed_less_equal_bound(&(-Bitvector::one(bound.width())))
+        } else if self.interval.start.sign_bit().to_bool() {
+            Ok(self)
+        } else {
+            self.add_signed_greater_equal_bound(bound)
+        }
+    }
+
+    fn add_not_equal_bound(mut self, bound: &Bitvector) -> Result<Self, Error> {
+        if self.interval.start == *bound && self.interval.end == *bound {
+            return Err(anyhow!("Empty interval"));
+        }
+        if self.interval.start.checked_sgt(bound).unwrap() {
+            self.add_signed_greater_equal_bound(&(bound + &Bitvector::one(bound.width())))
+        } else if self.interval.start == *bound {
+            self.interval.start += &Bitvector::one(bound.width());
+            Ok(self)
+        } else if self.interval.end.checked_slt(bound).unwrap() {
+            self.add_signed_less_equal_bound(&(bound - &Bitvector::one(bound.width())))
+        } else if self.interval.end == *bound {
+            self.interval.end -= &Bitvector::one(bound.width());
+            Ok(self)
+        } else {
+            Ok(self)
+        }
+    }
 }
 
 impl AbstractDomain for IntervalDomain {

src/cwe_checker_lib/src/abstract_domain/interval/bin_ops.rs

@@ -4,74 +4,66 @@ impl IntervalDomain {
     /// Compute the interval of possible results
     /// if one adds a value from `self` to a value from `rhs`.
     pub fn add(&self, rhs: &Self) -> Self {
-        let interval = self.interval.add(&rhs.interval);
+        let mut interval: IntervalDomain = self.interval.add(&rhs.interval).into();
         if interval.is_top() {
-            interval.into()
-        } else {
-            let new_lower_bound = if let (Some(self_bound), Some(rhs_bound)) =
-                (&self.widening_lower_bound, &rhs.widening_lower_bound)
-            {
-                if self_bound.signed_add_overflow_check(rhs_bound) {
-                    None
-                } else {
-                    Some(self_bound.clone().into_checked_add(rhs_bound).unwrap())
-                }
-            } else {
-                None
-            };
-            let new_upper_bound = if let (Some(self_bound), Some(rhs_bound)) =
-                (&self.widening_upper_bound, &rhs.widening_upper_bound)
-            {
-                if self_bound.signed_add_overflow_check(rhs_bound) {
-                    None
-                } else {
-                    Some(self_bound.clone().into_checked_add(rhs_bound).unwrap())
-                }
+            interval
         } else {
-                None
-            };
-            IntervalDomain {
-                interval,
-                widening_upper_bound: new_upper_bound,
-                widening_lower_bound: new_lower_bound,
-            }
+            interval.update_widening_lower_bound(
+                &self
+                    .widening_lower_bound
+                    .as_ref()
+                    .and_then(|bound| bound.signed_add_overflow_checked(&rhs.interval.start)),
+            );
+            interval.update_widening_lower_bound(
+                &rhs.widening_lower_bound
+                    .as_ref()
+                    .and_then(|bound| bound.signed_add_overflow_checked(&self.interval.start)),
+            );
+            interval.update_widening_upper_bound(
+                &self
+                    .widening_upper_bound
+                    .as_ref()
+                    .and_then(|bound| bound.signed_add_overflow_checked(&rhs.interval.end)),
+            );
+            interval.update_widening_upper_bound(
+                &rhs.widening_upper_bound
+                    .as_ref()
+                    .and_then(|bound| bound.signed_add_overflow_checked(&self.interval.end)),
+            );
+            interval
         }
     }
 
     /// Compute the interval of possible results
     /// if one subtracts a value in `rhs` from a value in `self`.
     pub fn sub(&self, rhs: &Self) -> Self {
-        let interval = self.interval.sub(&rhs.interval);
+        let mut interval: IntervalDomain = self.interval.sub(&rhs.interval).into();
         if interval.is_top() {
-            interval.into()
-        } else {
-            let new_lower_bound = if let (Some(self_bound), Some(rhs_bound)) =
-                (&self.widening_lower_bound, &rhs.widening_upper_bound)
-            {
-                if self_bound.signed_sub_overflow_check(rhs_bound) {
-                    None
-                } else {
-                    Some(self_bound.clone().into_checked_sub(rhs_bound).unwrap())
-                }
-            } else {
-                None
-            };
-            let new_upper_bound = if let (Some(self_bound), Some(rhs_bound)) =
-                (&self.widening_upper_bound, &rhs.widening_lower_bound)
-            {
-                if self_bound.signed_sub_overflow_check(rhs_bound) {
-                    None
-                } else {
-                    Some(self_bound.clone().into_checked_sub(rhs_bound).unwrap())
-                }
+            interval
         } else {
-                None
-            };
-            IntervalDomain {
-                interval,
-                widening_upper_bound: new_upper_bound,
-                widening_lower_bound: new_lower_bound,
-            }
+            interval.update_widening_lower_bound(
+                &self
+                    .widening_lower_bound
+                    .as_ref()
+                    .and_then(|bound| bound.signed_sub_overflow_checked(&rhs.interval.end)),
+            );
+            interval.update_widening_lower_bound(
+                &rhs.widening_upper_bound
+                    .as_ref()
+                    .and_then(|bound| self.interval.start.signed_sub_overflow_checked(bound)),
+            );
+            interval.update_widening_upper_bound(
+                &self
+                    .widening_upper_bound
+                    .as_ref()
+                    .and_then(|bound| bound.signed_sub_overflow_checked(&rhs.interval.start)),
+            );
+            interval.update_widening_upper_bound(
+                &rhs.widening_lower_bound
+                    .as_ref()
+                    .and_then(|bound| self.interval.end.signed_sub_overflow_checked(bound)),
+            );
+            interval
         }
     }
 

src/cwe_checker_lib/src/abstract_domain/interval/simple_interval.rs

@@ -55,6 +55,18 @@ impl Interval {
         Interval { start, end }
     }
 
+    /// Compute the intersection of two intervals as intervals of signed integers.
+    /// Return an error if the intersection is empty.
+    pub fn signed_intersect(&self, other: &Interval) -> Result<Interval, Error> {
+        let start = signed_max(&self.start, &other.start);
+        let end = signed_min(&self.end, &other.end);
+        if start.checked_sle(&end).unwrap() {
+            Ok(Interval { start, end })
+        } else {
+            Err(anyhow!("Empty interval"))
+        }
+    }
+
     /// Return the number of contained values of the interval as an unsigned bitvector.
     /// If the interval is unconstrained, return zero
     /// (since the maximal number of elements is not representable in a bitvector of the same byte size).
@@ -142,30 +154,26 @@ impl Interval {
     /// Compute the interval of possible results
     /// if one adds a value from `self` to a value from `rhs`.
     pub fn add(&self, rhs: &Interval) -> Interval {
-        if self.start.signed_add_overflow_check(&rhs.start)
-            || self.end.signed_add_overflow_check(&rhs.end)
-        {
-            Interval::new_top(self.bytesize())
+        if let (Some(start), Some(end)) = (
+            self.start.signed_add_overflow_checked(&rhs.start),
+            self.end.signed_add_overflow_checked(&rhs.end),
+        ) {
+            Interval { start, end }
         } else {
-            Interval {
-                start: self.start.clone().into_checked_add(&rhs.start).unwrap(),
-                end: self.end.clone().into_checked_add(&rhs.end).unwrap(),
-            }
+            Interval::new_top(self.bytesize())
         }
     }
 
     /// Compute the interval of possible results
     /// if one subtracts a value in `rhs` from a value in `self`.
     pub fn sub(&self, rhs: &Interval) -> Interval {
-        if self.start.signed_sub_overflow_check(&rhs.end)
-            || self.end.signed_sub_overflow_check(&rhs.start)
-        {
-            Interval::new_top(self.bytesize())
+        if let (Some(start), Some(end)) = (
+            self.start.signed_sub_overflow_checked(&rhs.end),
+            self.end.signed_sub_overflow_checked(&rhs.start),
+        ) {
+            Interval { start, end }
         } else {
-            Interval {
-                start: self.start.clone().into_checked_sub(&rhs.end).unwrap(),
-                end: self.end.clone().into_checked_sub(&rhs.start).unwrap(),
-            }
+            Interval::new_top(self.bytesize())
         }
     }
 
@@ -193,6 +201,12 @@ impl Interval {
             end: max,
         }
     }
+
+    /// Return `true` if `bitvec` is contained in the interval.
+    /// Panics if the interval and `bitvec` have different bytesizes.
+    pub fn contains(&self, bitvec: &Bitvector) -> bool {
+        self.start.checked_sle(bitvec).unwrap() && self.end.checked_sge(bitvec).unwrap()
+    }
 }
 
 impl From<Bitvector> for Interval {

src/cwe_checker_lib/src/abstract_domain/interval/tests.rs

@@ -228,18 +228,18 @@ fn add() {
     let result = lhs.bin_op(BinOpType::IntAdd, &rhs);
     assert_eq!(
         result,
-        IntervalDomain::mock_with_bounds(None, 0, 7, Some(20))
+        IntervalDomain::mock_with_bounds(Some(-17), 0, 7, Some(10))
     );
     let lhs = IntervalDomain::mock_i8_with_bounds(Some(-121), -120, -120, Some(10));
     let rhs = IntervalDomain::mock_i8_with_bounds(Some(-10), -9, 0, Some(10));
     let result = lhs.bin_op(BinOpType::IntAdd, &rhs);
     assert_eq!(result, IntervalDomain::new_top(ByteSize::new(1)));
-    let lhs = IntervalDomain::mock_i8_with_bounds(Some(-100), 2, 4, Some(100));
-    let rhs = IntervalDomain::mock_i8_with_bounds(Some(-50), 10, 20, Some(50));
+    let lhs = IntervalDomain::mock_i8_with_bounds(Some(-100), -30, 40, Some(100));
+    let rhs = IntervalDomain::mock_i8_with_bounds(Some(-100), -30, 20, Some(50));
     let result = lhs.bin_op(BinOpType::IntAdd, &rhs);
     assert_eq!(
         result,
-        IntervalDomain::mock_i8_with_bounds(None, 12, 24, None)
+        IntervalDomain::mock_i8_with_bounds(None, -60, 60, Some(90))
     );
 }
 
@@ -250,18 +250,18 @@ fn sub() {
     let result = lhs.bin_op(BinOpType::IntSub, &rhs);
     assert_eq!(
         result,
-        IntervalDomain::mock_with_bounds(None, 3, 10, Some(30))
+        IntervalDomain::mock_with_bounds(Some(-7), 3, 10, Some(13))
     );
     let lhs = IntervalDomain::mock_i8_with_bounds(Some(-121), -120, -120, Some(10));
     let rhs = IntervalDomain::mock_i8_with_bounds(Some(-10), -9, 9, Some(10));
     let result = lhs.bin_op(BinOpType::IntSub, &rhs);
     assert_eq!(result, IntervalDomain::new_top(ByteSize::new(1)));
-    let lhs = IntervalDomain::mock_i8_with_bounds(Some(-100), 2, 4, Some(100));
-    let rhs = IntervalDomain::mock_i8_with_bounds(Some(-50), 10, 20, Some(50));
+    let lhs = IntervalDomain::mock_i8_with_bounds(Some(-100), 2, 40, Some(100));
+    let rhs = IntervalDomain::mock_i8_with_bounds(Some(-50), -30, 3, Some(100));
     let result = lhs.bin_op(BinOpType::IntSub, &rhs);
     assert_eq!(
         result,
-        IntervalDomain::mock_i8_with_bounds(None, -18, -6, None)
+        IntervalDomain::mock_i8_with_bounds(Some(-98), -1, 70, Some(90))
     );
 }
 
@@ -315,3 +315,191 @@ fn shift_left() {
     let result = lhs.bin_op(BinOpType::IntLeft, &rhs);
     assert_eq!(result, IntervalDomain::mock(0, 0));
 }
+
+#[test]
+fn simple_interval_contains() {
+    let domain = IntervalDomain::mock(-10, 5);
+    assert!(!domain.interval.contains(&Bitvector::from_i64(-11)));
+    assert!(domain.interval.contains(&Bitvector::from_i64(-10)));
+    assert!(domain.interval.contains(&Bitvector::from_i64(-4)));
+    assert!(domain.interval.contains(&Bitvector::from_i64(5)));
+    assert!(!domain.interval.contains(&Bitvector::from_i64(6)));
+}
+
+#[test]
+fn add_signed_bounds() {
+    let interval = IntervalDomain::mock_with_bounds(Some(-100), -10, 10, Some(100));
+
+    // signed_less_equal
+    let x = interval
+        .clone()
+        .add_signed_less_equal_bound(&Bitvector::from_i64(20));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(Some(-100), -10, 10, Some(20))
+    );
+    let x = interval
+        .clone()
+        .add_signed_less_equal_bound(&Bitvector::from_i64(-5));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(Some(-100), -10, -5, None)
+    );
+    let x = interval
+        .clone()
+        .add_signed_less_equal_bound(&Bitvector::from_i64(-20));
+    assert!(x.is_err());
+
+    //signed_greater_equal
+    let x = interval
+        .clone()
+        .add_signed_greater_equal_bound(&Bitvector::from_i64(20));
+    assert!(x.is_err());
+    let x = interval
+        .clone()
+        .add_signed_greater_equal_bound(&Bitvector::from_i64(-5));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(None, -5, 10, Some(100))
+    );
+    let x = interval
+        .clone()
+        .add_signed_greater_equal_bound(&Bitvector::from_i64(-20));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(Some(-20), -10, 10, Some(100))
+    );
+}
+
+#[test]
+fn add_unsigned_bounds() {
+    let positive_interval = IntervalDomain::mock_with_bounds(Some(10), 20, 30, Some(40));
+    let wrapped_interval = IntervalDomain::mock_with_bounds(Some(-100), -10, 10, Some(100));
+    let negative_interval = IntervalDomain::mock_with_bounds(Some(-40), -30, -20, Some(-10));
+
+    // unsigned_less_equal
+    let x = positive_interval
+        .clone()
+        .add_unsigned_less_equal_bound(&Bitvector::from_i64(35));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(Some(10), 20, 30, Some(35))
+    );
+    let x = positive_interval
+        .clone()
+        .add_unsigned_less_equal_bound(&Bitvector::from_i64(15));
+    assert!(x.is_err());
+
+    let x = wrapped_interval
+        .clone()
+        .add_unsigned_less_equal_bound(&Bitvector::from_i64(35));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(None, 0, 10, Some(35))
+    );
+    let x = wrapped_interval
+        .clone()
+        .add_unsigned_less_equal_bound(&Bitvector::from_i64(-5));
+    assert_eq!(x.unwrap(), wrapped_interval); // Cannot remove a subinterval from the domain
+
+    let x = negative_interval
+        .clone()
+        .add_unsigned_less_equal_bound(&Bitvector::from_i64(-25));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(Some(-40), -30, -25, None)
+    );
+    let x = negative_interval
+        .clone()
+        .add_unsigned_less_equal_bound(&Bitvector::from_i64(-35));
+    assert!(x.is_err());
+
+    // unsigned_greater_equal
+    let x = positive_interval
+        .clone()
+        .add_unsigned_greater_equal_bound(&Bitvector::from_i64(25));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(None, 25, 30, Some(40))
+    );
+    let x = positive_interval
+        .clone()
+        .add_unsigned_greater_equal_bound(&Bitvector::from_i64(35));
+    assert!(x.is_err());
+
+    let x = wrapped_interval
+        .clone()
+        .add_unsigned_greater_equal_bound(&Bitvector::from_i64(5));
+    assert_eq!(x.unwrap(), wrapped_interval);
+    let x = wrapped_interval
+        .clone()
+        .add_unsigned_greater_equal_bound(&Bitvector::from_i64(35));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(Some(-100), -10, -1, None)
+    );
+    let x = wrapped_interval
+        .clone()
+        .add_unsigned_greater_equal_bound(&Bitvector::from_i64(-50));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(Some(-50), -10, -1, None)
+    );
+
+    let x = negative_interval
+        .clone()
+        .add_unsigned_greater_equal_bound(&Bitvector::from_i64(25));
+    assert_eq!(x.unwrap(), negative_interval);
+    let x = negative_interval
+        .clone()
+        .add_unsigned_greater_equal_bound(&Bitvector::from_i64(-25));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(None, -25, -20, Some(-10))
+    );
+}
+
+#[test]
+fn add_not_equal_bounds() {
+    let interval = IntervalDomain::mock_with_bounds(None, -10, 10, None);
+
+    let x = interval
+        .clone()
+        .add_not_equal_bound(&Bitvector::from_i64(-20));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(Some(-19), -10, 10, None)
+    );
+    let x = interval
+        .clone()
+        .add_not_equal_bound(&Bitvector::from_i64(-0));
+    assert_eq!(x.unwrap(), interval);
+    let x = interval
+        .clone()
+        .add_not_equal_bound(&Bitvector::from_i64(20));
+    assert_eq!(
+        x.unwrap(),
+        IntervalDomain::mock_with_bounds(None, -10, 10, Some(19))
+    );
+
+    let interval = IntervalDomain::mock(5, 5);
+    let x = interval
+        .clone()
+        .add_not_equal_bound(&Bitvector::from_i64(5));
+    assert!(x.is_err());
+    let interval = IntervalDomain::mock(5, 6);
+    let x = interval.add_not_equal_bound(&Bitvector::from_i64(5));
+    assert_eq!(x.unwrap(), IntervalDomain::mock(6, 6));
+}
+
+#[test]
+fn intersection() {
+    let interval1 = IntervalDomain::mock_with_bounds(Some(-100), -10, 10, Some(100));
+    let interval2 = IntervalDomain::mock_with_bounds(Some(-20), 2, 30, None);
+    let intersection = interval1.intersect(&interval2).unwrap();
+    assert_eq!(
+        intersection,
+        IntervalDomain::mock_with_bounds(Some(-20), 2, 10, Some(100))
+    );
+    assert!(interval1.intersect(&IntervalDomain::mock(50, 55)).is_err());
+}

src/cwe_checker_lib/src/abstract_domain/mod.rs

@@ -123,3 +123,34 @@ pub trait TryToInterval {
         Ok((interval.start.try_to_i64()?, interval.end.try_to_i64()?))
     }
 }
+
+/// A trait for domains whose values can be restricted by knowing the result of a comparison of it with a known bitvector.
+/// The comparison may also be used to add widening hints to the domain.
+///
+/// Note that the value set represented by the domain after the restriction may be an upper bound,
+/// i.e. it is possible that the result still contains values not satisfying the restricting comparison.
+pub trait SpecializeByConditional: Sized {
+    /// Return the restriction of `self` to values satisfying `self <= bound`
+    /// with `self` and `bound` interpreted as signed integers.
+    /// Returns an error if no value represented by `self` can satisfy the comparison.
+    fn add_signed_less_equal_bound(self, bound: &Bitvector) -> Result<Self, Error>;
+
+    /// Return the restriction of `self` to values satisfying `self <= bound`
+    /// with `self` and `bound` interpreted as unsigned integers.
+    /// Returns an error if no value represented by `self` can satisfy the comparison.
+    fn add_unsigned_less_equal_bound(self, bound: &Bitvector) -> Result<Self, Error>;
+
+    /// Return the restriction of `self` to values satisfying `self >= bound`
+    /// with `self` and `bound` interpreted as signed integers.
+    /// Returns an error if no value represented by `self` can satisfy the comparison.
+    fn add_signed_greater_equal_bound(self, bound: &Bitvector) -> Result<Self, Error>;
+
+    /// Return the restriction of `self` to values satisfying `self >= bound`
+    /// with `self` and `bound` interpreted as unsigned integers.
+    /// Returns an error if no value represented by `self` can satisfy the comparison.
+    fn add_unsigned_greater_equal_bound(self, bound: &Bitvector) -> Result<Self, Error>;
+
+    /// Return the restriction of `self` to values satisfying `self != bound`
+    /// Returns an error if `self` only represents one value for which `self == bound` holds.
+    fn add_not_equal_bound(self, bound: &Bitvector) -> Result<Self, Error>;
+}

src/cwe_checker_lib/src/analysis/backward_interprocedural_fixpoint/mod.rs

@@ -165,13 +165,13 @@ impl<'a, T: Context<'a>> GeneralFPContext for GeneralizedContext<'a, T> {
             // The CallStub Edge value is added to the CallSourceCombinator
             // The user has the ability to split the node value at the BlkStart return to node
             // to only send specific data along the CallStub Edge to the callsite
-            Edge::CRCallStub => Some(NodeValue::CallFlowCombinator {
+            Edge::CrCallStub => Some(NodeValue::CallFlowCombinator {
                 call_stub: self.context.split_call_stub(node_value.unwrap_value()),
                 interprocedural_flow: None,
             }),
             // The user has the ability to split the node value at the BlkStart return node
             // to only send specific data along the ReturnStub Edge to the last BlkEnd node called subroutine
-            Edge::CRReturnStub => {
+            Edge::CrReturnStub => {
                 // The subroutine term from which the program returns
                 let returned_from_sub = match graph.node_weight(end_node) {
                     Some(Node::BlkEnd { 0: _, 1: sub_term }) => sub_term,

src/cwe_checker_lib/src/analysis/forward_interprocedural_fixpoint.rs

@@ -79,6 +79,7 @@ pub trait Context<'a> {
         &self,
         value: &Self::Value,
         condition: &Expression,
+        block_before_condition: &Term<Blk>,
         is_true: bool,
     ) -> Option<Self::Value>;
 }
@@ -164,11 +165,11 @@ impl<'a, T: Context<'a>> GeneralFPContext for GeneralizedContext<'a, T> {
                 .context
                 .update_call(node_value.unwrap_value(), call, &graph[end_node])
                 .map(NodeValue::Value),
-            Edge::CRCallStub => Some(NodeValue::CallFlowCombinator {
+            Edge::CrCallStub => Some(NodeValue::CallFlowCombinator {
                 call_stub: Some(node_value.unwrap_value().clone()),
                 interprocedural_flow: None,
             }),
-            Edge::CRReturnStub => Some(NodeValue::CallFlowCombinator {
+            Edge::CrReturnStub => Some(NodeValue::CallFlowCombinator {
                 call_stub: None,
                 interprocedural_flow: Some(node_value.unwrap_value().clone()),
             }),
@@ -201,15 +202,51 @@ impl<'a, T: Context<'a>> GeneralFPContext for GeneralizedContext<'a, T> {
                 .context
                 .update_call_stub(node_value.unwrap_value(), call)
                 .map(NodeValue::Value),
-            Edge::Jump(jump, untaken_conditional) => self
-                .context
-                .update_jump(
+            Edge::Jump(jump, untaken_conditional) => {
+                let value_after_condition = if let Jmp::CBranch {
+                    target: _,
+                    condition,
+                } = &jump.term
+                {
+                    let block = graph[start_node].get_block();
+                    self.context.specialize_conditional(
+                        node_value.unwrap_value(),
+                        condition,
+                        block,
+                        true,
+                    )
+                } else if let Some(untaken_conditional_jump) = untaken_conditional {
+                    if let Jmp::CBranch {
+                        target: _,
+                        condition,
+                    } = &untaken_conditional_jump.term
+                    {
+                        let block = graph[start_node].get_block();
+                        self.context.specialize_conditional(
                             node_value.unwrap_value(),
+                            condition,
+                            block,
+                            false,
+                        )
+                    } else {
+                        panic!("Malformed control flow graph");
+                    }
+                } else {
+                    Some(node_value.unwrap_value().clone())
+                };
+                if let Some(value) = value_after_condition {
+                    self.context
+                        .update_jump(
+                            &value,
                             jump,
                             *untaken_conditional,
                             graph[end_node].get_block(),
                         )
-                .map(NodeValue::Value),
+                        .map(NodeValue::Value)
+                } else {
+                    None
+                }
+            }
         }
     }
 }

src/cwe_checker_lib/src/analysis/graph.rs

@@ -150,9 +150,9 @@ pub enum Edge<'a> {
     /// The edge goes directly from the callsite to the return-to-site inside the caller.
     ExternCallStub(&'a Term<Jmp>),
     /// An artificial edge. See the module-level documentation for more information.
-    CRCallStub,
+    CrCallStub,
     /// An artificial edge. See the module-level documentation for more information.
-    CRReturnStub,
+    CrReturnStub,
     /// An artificial edge to combine intra- and interprocedural data flows at the callsite of calls.
     /// See the module-level documentation for more information.
     CallCombine(&'a Term<Jmp>),
@@ -425,9 +425,9 @@ impl<'a> GraphBuilder<'a> {
                 return_: (return_from_block, return_from_sub),
             });
             self.graph
-                .add_edge(*call_node, return_combine_node, Edge::CRCallStub);
+                .add_edge(*call_node, return_combine_node, Edge::CrCallStub);
             self.graph
-                .add_edge(return_source, return_combine_node, Edge::CRReturnStub);
+                .add_edge(return_source, return_combine_node, Edge::CrReturnStub);
             self.graph.add_edge(
                 return_combine_node,
                 *return_to_node,

src/cwe_checker_lib/src/analysis/pointer_inference/context/mod.rs

@@ -90,7 +90,7 @@ impl<'a> Context<'a> {
             _ => Bitvector::zero(apint::BitWidth::from(self.project.get_pointer_bytesize())),
         };
         match state_before_return.get_register(&self.project.stack_pointer_register) {
-            Ok(Data::Pointer(pointer)) => {
+            Data::Pointer(pointer) => {
                 if pointer.targets().len() == 1 {
                     let (id, offset) = pointer.targets().iter().next().unwrap();
                     if *id != state_before_return.stack_id
@@ -106,11 +106,10 @@ impl<'a> Context<'a> {
                     ))
                 }
             }
-            Ok(Data::Top(_)) => Err(anyhow!(
+            Data::Top(_) => Err(anyhow!(
                 "Stack register value lost during function execution"
             )),
-            Ok(Data::Value(_)) => Err(anyhow!("Unexpected stack register value on return")),
-            Err(err) => Err(err),
+            Data::Value(_) => Err(anyhow!("Unexpected stack register value on return")),
         }
     }
 
@@ -258,11 +257,7 @@ impl<'a> Context<'a> {
     /// Check whether the jump is an indirect call whose target evaluates to a *Top* value in the given state.
     fn is_indirect_call_with_top_target(&self, state: &State, call: &Term<Jmp>) -> bool {
         match &call.term {
-            Jmp::CallInd { target, .. }
-                if state.eval(target).map_or(false, |value| value.is_top()) =>
-            {
-                true
-            }
+            Jmp::CallInd { target, .. } => state.eval(target).is_top(),
             _ => false,
         }
     }
@@ -280,7 +275,7 @@ impl<'a> Context<'a> {
         new_state: &mut State,
     ) {
         let stack_register = &self.project.stack_pointer_register;
-        let stack_pointer = state_before_call.get_register(stack_register).unwrap();
+        let stack_pointer = state_before_call.get_register(stack_register);
         match self.project.cpu_architecture.as_str() {
             "x86" | "x86_64" => {
                 let offset = Bitvector::from_u64(stack_register.size.into())
@@ -382,7 +377,7 @@ impl<'a> Context<'a> {
 
     /// Get the offset of the current stack pointer to the base of the current stack frame.
     fn get_current_stack_offset(&self, state: &State) -> ValueDomain {
-        if let Ok(Data::Pointer(ref stack_pointer)) =
+        if let Data::Pointer(ref stack_pointer) =
             state.get_register(&self.project.stack_pointer_register)
         {
             if stack_pointer.targets().len() == 1 {

src/cwe_checker_lib/src/analysis/pointer_inference/context/tests.rs

@@ -130,7 +130,7 @@ fn context_problem_implementation() {
     // test update_def
     state = context.update_def(&state, &def).unwrap();
     let stack_pointer = Data::Pointer(PointerDomain::new(new_id("main", "RSP"), bv(-16)));
-    assert_eq!(state.eval(&Var(register("RSP"))).unwrap(), stack_pointer);
+    assert_eq!(state.eval(&Var(register("RSP"))), stack_pointer);
     state = context.update_def(&state, &store_term).unwrap();
 
     // Test update_call
@@ -194,10 +194,9 @@ fn context_problem_implementation() {
     assert_eq!(return_state.caller_stack_ids, BTreeSet::new());
     assert_eq!(return_state.memory, state.memory);
     assert_eq!(
-        return_state.get_register(&register("RSP")).unwrap(),
+        return_state.get_register(&register("RSP")),
         state
             .get_register(&register("RSP"))
-            .unwrap()
             .bin_op(BinOpType::IntAdd, &Bitvector::from_i64(8).into())
     );
 
@@ -207,7 +206,7 @@ fn context_problem_implementation() {
     let malloc = call_term("extern_malloc");
     let mut state_after_malloc = context.update_call_stub(&state, &malloc).unwrap();
     assert_eq!(
-        state_after_malloc.get_register(&register("RDX")).unwrap(),
+        state_after_malloc.get_register(&register("RDX")),
         Data::Pointer(PointerDomain::new(
             new_id("call_extern_malloc", "RDX"),
             bv(0)
@@ -215,21 +214,17 @@ fn context_problem_implementation() {
     );
     assert_eq!(state_after_malloc.memory.get_num_objects(), 2);
     assert_eq!(
-        state_after_malloc.get_register(&register("RSP")).unwrap(),
+        state_after_malloc.get_register(&register("RSP")),
         state
             .get_register(&register("RSP"))
-            .unwrap()
             .bin_op(BinOpType::IntAdd, &Data::Value(bv(8)))
     );
     assert_eq!(
-        state_after_malloc
-            .get_register(&register("callee_saved_reg"))
-            .unwrap(),
+        state_after_malloc.get_register(&register("callee_saved_reg")),
         Data::Value(bv(13))
     );
     assert!(state_after_malloc
         .get_register(&register("other_reg"))
-        .unwrap()
         .is_top());
 
     state_after_malloc.set_register(
@@ -243,15 +238,10 @@ fn context_problem_implementation() {
     let state_after_free = context
         .update_call_stub(&state_after_malloc, &free)
         .unwrap();
-    assert!(state_after_free
-        .get_register(&register("RDX"))
-        .unwrap()
-        .is_top());
+    assert!(state_after_free.get_register(&register("RDX")).is_top());
     assert_eq!(state_after_free.memory.get_num_objects(), 2);
     assert_eq!(
-        state_after_free
-            .get_register(&register("callee_saved_reg"))
-            .unwrap(),
+        state_after_free.get_register(&register("callee_saved_reg")),
         Data::Pointer(PointerDomain::new(
             new_id("call_extern_malloc", "RDX"),
             bv(0)
@@ -262,21 +252,17 @@ fn context_problem_implementation() {
     let state_after_other_fn = context.update_call_stub(&state, &other_extern_fn).unwrap();
 
     assert_eq!(
-        state_after_other_fn.get_register(&register("RSP")).unwrap(),
+        state_after_other_fn.get_register(&register("RSP")),
         state
             .get_register(&register("RSP"))
-            .unwrap()
             .bin_op(BinOpType::IntAdd, &Data::Value(bv(8)))
     );
     assert_eq!(
-        state_after_other_fn
-            .get_register(&register("callee_saved_reg"))
-            .unwrap(),
+        state_after_other_fn.get_register(&register("callee_saved_reg")),
         Data::Value(bv(13))
     );
     assert!(state_after_other_fn
         .get_register(&register("other_reg"))
-        .unwrap()
         .is_top());
 }
 
@@ -380,10 +366,119 @@ fn update_return() {
         .get_all_object_ids()
         .get(&new_id("caller_caller", "RSP"))
         .is_some());
-    assert!(state.get_register(&register("RSP")).is_ok());
     let expected_rsp = Data::Pointer(PointerDomain::new(
         new_id("original_caller_id", "RSP"),
         bv(-8),
     ));
-    assert_eq!(state.get_register(&register("RSP")).unwrap(), expected_rsp);
+    assert_eq!(state.get_register(&register("RSP")), expected_rsp);
+}
+
+#[test]
+fn specialize_conditional() {
+    use crate::analysis::forward_interprocedural_fixpoint::Context as IpFpContext;
+    let (project, config) = mock_project();
+    let graph = crate::analysis::graph::get_program_cfg(&project.program, HashSet::new());
+    let runtime_memory_image = RuntimeMemoryImage::mock();
+    let (log_sender, _log_receiver) = crossbeam_channel::unbounded();
+    let context = Context::new(&project, &runtime_memory_image, &graph, config, log_sender);
+
+    let mut state = State::new(&register("RSP"), Tid::new("func"));
+    state.set_register(&register("RAX"), IntervalDomain::mock(-10, 20).into());
+
+    let condition = Expression::Var(Variable::mock("FLAG", 1));
+
+    // A complicated way of computing the result of `RAX <= 0`
+    // and assigning the result to the `FLAG` register.
+    let defs = vec![
+        Def::assign("def1", register("RAX"), Expression::Var(register("RAX"))),
+        Def::assign(
+            "def_that_should_be_ignored",
+            Variable::mock("FLAG", 1),
+            Expression::Const(Bitvector::from_u8(42)),
+        ),
+        Def::assign(
+            "def2",
+            Variable::mock("FLAG_SLESS", 1),
+            Expression::BinOp {
+                lhs: Box::new(Expression::Var(register("RAX"))),
+                op: BinOpType::IntSLess,
+                rhs: Box::new(Expression::Const(Bitvector::from_u64(0))),
+            },
+        ),
+        Def::assign(
+            "def3",
+            Variable::mock("FLAG_EQUAL", 1),
+            Expression::BinOp {
+                lhs: Box::new(Expression::Var(register("RAX"))),
+                op: BinOpType::IntEqual,
+                rhs: Box::new(Expression::Const(Bitvector::from_u64(0))),
+            },
+        ),
+        Def::assign(
+            "def4",
+            Variable::mock("FLAG_NOTEQUAL", 1),
+            Expression::BinOp {
+                lhs: Box::new(Expression::Var(Variable::mock("FLAG_SLESS", 1))),
+                op: BinOpType::IntNotEqual,
+                rhs: Box::new(Expression::Const(Bitvector::from_u8(0))),
+            },
+        ),
+        Def::assign(
+            "def5",
+            Variable::mock("FLAG", 1),
+            Expression::BinOp {
+                lhs: Box::new(Expression::Var(Variable::mock("FLAG_EQUAL", 1))),
+                op: BinOpType::BoolOr,
+                rhs: Box::new(Expression::Var(Variable::mock("FLAG_NOTEQUAL", 1))),
+            },
+        ),
+    ];
+
+    let block = Term {
+        tid: Tid::new("block"),
+        term: Blk {
+            defs,
+            jmps: Vec::new(),
+            indirect_jmp_targets: Vec::new(),
+        },
+    };
+
+    let result = context
+        .specialize_conditional(&state, &condition, &block, false)
+        .unwrap();
+    assert_eq!(
+        result.get_register(&Variable::mock("FLAG", 1)),
+        Bitvector::from_u8(0).into()
+    );
+    assert_eq!(
+        result.get_register(&Variable::mock("FLAG_NOTEQUAL", 1)),
+        Bitvector::from_u8(0).into()
+    );
+    assert_eq!(
+        result.get_register(&Variable::mock("FLAG_EQUAL", 1)),
+        Bitvector::from_u8(0).into()
+    );
+    assert_eq!(
+        result.get_register(&Variable::mock("FLAG_SLESS", 1)),
+        Bitvector::from_u8(0).into()
+    );
+    // The result is technically false, since RAX == 0 should be excluded.
+    // This impreciseness is due to the way that the result is calculated.
+    assert_eq!(
+        result.get_register(&register("RAX")),
+        IntervalDomain::mock(0, 20).into()
+    );
+
+    state.set_register(&register("RAX"), IntervalDomain::mock(0, 20).into());
+    let result = context
+        .specialize_conditional(&state, &condition, &block, false)
+        .unwrap();
+    assert_eq!(
+        result.get_register(&register("RAX")),
+        IntervalDomain::mock_with_bounds(Some(0), 1, 20, None).into()
+    );
+
+    state.set_register(&register("RAX"), IntervalDomain::mock(-20, 0).into());
+    let result = context.specialize_conditional(&state, &condition, &block, false);
+    assert!(result.is_none());
 }

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

 use super::*;
+use std::collections::HashSet;
 
 impl<'a> crate::analysis::forward_interprocedural_fixpoint::Context<'a> for Context<'a> {
     type Value = State;
@@ -43,7 +44,7 @@ impl<'a> crate::analysis::forward_interprocedural_fixpoint::Context<'a> for Cont
             }
             Def::Assign { var, value } => {
                 let mut new_state = state.clone();
-                self.log_debug(new_state.handle_register_assign(var, value), Some(&def.tid));
+                new_state.handle_register_assign(var, value);
                 Some(new_state)
             }
             Def::Load { var, address } => {
@@ -291,13 +292,55 @@ impl<'a> crate::analysis::forward_interprocedural_fixpoint::Context<'a> for Cont
     }
 
     /// Update the state with the knowledge that some conditional evaluated to true or false.
-    /// Currently not implemented, this function just returns the state as it is.
     fn specialize_conditional(
         &self,
         value: &State,
-        _condition: &Expression,
-        _is_true: bool,
+        condition: &Expression,
+        block_before_condition: &Term<Blk>,
+        is_true: bool,
     ) -> Option<State> {
-        Some(value.clone())
+        let mut specialized_state = value.clone();
+        if specialized_state
+            .specialize_by_expression_result(condition, Bitvector::from_u8(is_true as u8).into())
+            .is_err()
+        {
+            // State is unsatisfiable
+            return None;
+        }
+        let mut modified_vars: HashSet<Variable> = HashSet::new();
+        for def in block_before_condition.term.defs.iter().rev() {
+            match &def.term {
+                Def::Store { .. } => (),
+                Def::Load { var, .. } => {
+                    modified_vars.insert(var.clone());
+                }
+                Def::Assign {
+                    var,
+                    value: input_expr,
+                } => {
+                    if !modified_vars.contains(var) {
+                        // Register is not modified again between the `Def` and the end of the block.
+                        modified_vars.insert(var.clone());
+                        if input_expr
+                            .input_vars()
+                            .into_iter()
+                            .find(|input_var| modified_vars.contains(input_var))
+                            .is_none()
+                        {
+                            // Values of input registers did not change between the `Def` and the end of the block.
+                            let expr_result = specialized_state.get_register(var);
+                            if specialized_state
+                                .specialize_by_expression_result(input_expr, expr_result.clone())
+                                .is_err()
+                            {
+                                // State is unsatisfiable
+                                return None;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        Some(specialized_state)
     }
 }

src/cwe_checker_lib/src/analysis/pointer_inference/mod.rs

@@ -338,33 +338,21 @@ impl<'a> PointerInference<'a> {
                             for jmp in block.term.jmps.iter() {
                                 match &jmp.term {
                                     Jmp::BranchInd(target_expr) => {
-                                        if let Ok(address) = state.eval(&target_expr) {
+                                        let address = state.eval(&target_expr);
                                         println!(
                                             "{}: Indirect jump to {}",
                                             jmp.tid,
                                             address.to_json_compact()
                                         );
-                                        } else {
-                                            println!(
-                                                "{}: Indirect jump. Could not compute address",
-                                                jmp.tid
-                                            );
-                                        }
                                     }
                                     Jmp::CallInd { target, return_ } => {
-                                        if let Ok(address) = state.eval(&target) {
+                                        let address = state.eval(&target);
                                         println!(
                                             "{}: Indirect call to {}. HasReturn: {}",
                                             jmp.tid,
                                             address.to_json_compact(),
                                             return_.is_some()
                                         );
-                                        } else {
-                                            println!(
-                                                "{}: Indirect call. Could not compute address",
-                                                jmp.tid
-                                            );
-                                        }
                                     }
                                     Jmp::Return(_) => {
                                         if !state.caller_stack_ids.is_empty() {

src/cwe_checker_lib/src/analysis/pointer_inference/object.rs

@@ -258,19 +258,20 @@ impl AbstractObjectInfo {
     /// Get a more compact json-representation of the abstract object.
     /// Intended for pretty printing, not useable for serialization/deserialization.
     pub fn to_json_compact(&self) -> serde_json::Value {
-        let mut elements = Vec::new();
-        elements.push((
+        let mut elements = vec![
+            (
                 "is_unique".to_string(),
                 serde_json::Value::String(format!("{}", self.is_unique)),
-        ));
-        elements.push((
+            ),
+            (
                 "state".to_string(),
                 serde_json::Value::String(format!("{:?}", self.state)),
-        ));
-        elements.push((
+            ),
+            (
                 "type".to_string(),
                 serde_json::Value::String(format!("{:?}", self.type_)),
-        ));
+            ),
+        ];
         let memory = self
             .memory
             .iter()

src/cwe_checker_lib/src/analysis/pointer_inference/state/access_handling.rs

@@ -4,13 +4,11 @@ use super::*;
 
 impl State {
     /// Get the value of a register or Top() if no value is known.
-    ///
-    /// Returns an error if the variable is not a register.
-    pub fn get_register(&self, variable: &Variable) -> Result<Data, Error> {
+    pub fn get_register(&self, variable: &Variable) -> Data {
         if let Some(data) = self.register.get(variable) {
-            Ok(data.clone())
+            data.clone()
         } else {
-            Ok(Data::new_top(variable.size))
+            Data::new_top(variable.size)
         }
     }
 
@@ -28,8 +26,6 @@ impl State {
     }
 
     /// Set the value of a register.
-    ///
-    /// Returns an error if the variable is not a register.
     pub fn set_register(&mut self, variable: &Variable, value: Data) {
         if !value.is_top() {
             self.register.insert(variable.clone(), value);
@@ -39,21 +35,8 @@ impl State {
     }
 
     /// Evaluate expression on the given state and write the result to the target register.
-    pub fn handle_register_assign(
-        &mut self,
-        target: &Variable,
-        expression: &Expression,
-    ) -> Result<(), Error> {
-        match self.eval(expression) {
-            Ok(new_value) => {
-                self.set_register(target, new_value);
-                Ok(())
-            }
-            Err(err) => {
-                self.set_register(target, Data::new_top(target.size));
-                Err(err)
-            }
-        }
+    pub fn handle_register_assign(&mut self, target: &Variable, expression: &Expression) {
+        self.set_register(target, self.eval(expression))
     }
 
     /// Store `value` at the given `address`.
@@ -116,32 +99,19 @@ impl State {
         value: &Data,
         global_memory: &RuntimeMemoryImage,
     ) -> Result<(), Error> {
-        match self.eval(address) {
-            Ok(address_data) => self.store_value(&address_data, value, global_memory),
-            Err(err) => Err(err),
-        }
+        let address_data = self.eval(address);
+        self.store_value(&address_data, value, global_memory)
     }
 
     /// Evaluate the store instruction, given by its address and value expressions,
     /// and modify the state accordingly.
-    ///
-    /// If an error occurs, the state is still modified before the error is returned.
-    /// E.g. if the value expression cannot be evaluated,
-    /// the value at the target address is overwritten with a `Top` value.
     pub fn handle_store(
         &mut self,
         address: &Expression,
         value: &Expression,
         global_memory: &RuntimeMemoryImage,
     ) -> Result<(), Error> {
-        match self.eval(value) {
-            Ok(data) => self.write_to_address(address, &data, global_memory),
-            Err(err) => {
-                // we still need to write to the target location before reporting the error
-                self.write_to_address(address, &Data::new_top(value.bytesize()), global_memory)?;
-                Err(err)
-            }
-        }
+        self.write_to_address(address, &self.eval(value), global_memory)
     }
 
     /// Evaluate the given load instruction and return the data read on success.
@@ -151,7 +121,7 @@ impl State {
         size: ByteSize,
         global_memory: &RuntimeMemoryImage,
     ) -> Result<Data, Error> {
-        let address = self.adjust_pointer_for_read(&self.eval(address)?);
+        let address = self.adjust_pointer_for_read(&self.eval(address));
         match address {
             Data::Value(global_address) => {
                 if let Ok(address_bitvector) = global_address.try_to_bitvec() {
@@ -233,30 +203,30 @@ impl State {
     }
 
     /// Evaluate the value of an expression in the current state
-    pub fn eval(&self, expression: &Expression) -> Result<Data, Error> {
+    pub fn eval(&self, expression: &Expression) -> Data {
         use Expression::*;
         match expression {
             Var(variable) => self.get_register(&variable),
-            Const(bitvector) => Ok(bitvector.clone().into()),
+            Const(bitvector) => bitvector.clone().into(),
             BinOp { op, lhs, rhs } => {
                 if *op == BinOpType::IntXOr && lhs == rhs {
                     // the result of `x XOR x` is always zero.
-                    return Ok(Bitvector::zero(apint::BitWidth::from(lhs.bytesize())).into());
+                    return Bitvector::zero(apint::BitWidth::from(lhs.bytesize())).into();
                 }
-                let (left, right) = (self.eval(lhs)?, self.eval(rhs)?);
-                Ok(left.bin_op(*op, &right))
+                let (left, right) = (self.eval(lhs), self.eval(rhs));
+                left.bin_op(*op, &right)
             }
-            UnOp { op, arg } => Ok(self.eval(arg)?.un_op(*op)),
-            Cast { op, size, arg } => Ok(self.eval(arg)?.cast(*op, *size)),
+            UnOp { op, arg } => self.eval(arg).un_op(*op),
+            Cast { op, size, arg } => self.eval(arg).cast(*op, *size),
             Unknown {
                 description: _,
                 size,
-            } => Ok(Data::new_top(*size)),
+            } => Data::new_top(*size),
             Subpiece {
                 low_byte,
                 size,
                 arg,
-            } => Ok(self.eval(arg)?.subpiece(*low_byte, *size)),
+            } => self.eval(arg).subpiece(*low_byte, *size),
         }
     }
 
@@ -268,7 +238,7 @@ impl State {
         global_memory: &RuntimeMemoryImage,
     ) -> Result<Data, Error> {
         match parameter {
-            Arg::Register(var) => self.eval(&Expression::Var(var.clone())),
+            Arg::Register(var) => Ok(self.eval(&Expression::Var(var.clone()))),
             Arg::Stack { offset, size } => self.load_value(
                 &Expression::Var(stack_pointer.clone()).plus_const(*offset),
                 *size,
@@ -281,11 +251,7 @@ impl State {
     pub fn contains_access_of_dangling_memory(&self, def: &Def) -> bool {
         match def {
             Def::Load { address, .. } | Def::Store { address, .. } => {
-                if let Ok(pointer) = self.eval(address) {
-                    self.memory.is_dangling_pointer(&pointer, true)
-                } else {
-                    false
-                }
+                self.memory.is_dangling_pointer(&self.eval(address), true)
             }
             _ => false,
         }

src/cwe_checker_lib/src/checkers/cwe_476/context.rs

@@ -197,24 +197,22 @@ impl<'a> Context<'a> {
             for parameter in extern_symbol.parameters.iter() {
                 match parameter {
                     Arg::Register(var) => {
-                        if let Ok(data) = pi_state.eval(&Expression::Var(var.clone())) {
+                        let data = pi_state.eval(&Expression::Var(var.clone()));
                         if state.check_if_address_points_to_taint(data, pi_state) {
                             return true;
                         }
                     }
-                    }
                     Arg::Stack { offset, size } => {
-                        if let Ok(stack_address) = pi_state.eval(
+                        let stack_address = pi_state.eval(
                             &Expression::Var(self.project.stack_pointer_register.clone())
                                 .plus_const(*offset),
-                        ) {
+                        );
                         if state
                             .load_taint_from_memory(&stack_address, *size)
                             .is_tainted()
                         {
                             return true;
                         }
-                        }
                         if let Ok(stack_param) = pi_state.eval_parameter_arg(
                             parameter,
                             &self.project.stack_pointer_register,
@@ -266,6 +264,7 @@ impl<'a> crate::analysis::forward_interprocedural_fixpoint::Context<'a> for Cont
         &self,
         state: &State,
         _condition: &Expression,
+        _block_before_condition: &Term<Blk>,
         _is_true: bool,
     ) -> Option<State> {
         Some(state.clone())
@@ -332,10 +331,9 @@ impl<'a> crate::analysis::forward_interprocedural_fixpoint::Context<'a> for Cont
                 } else if let Some(pi_state) =
                     self.get_current_pointer_inference_state(state, &def.tid)
                 {
-                    if let Ok(address_data) = pi_state.eval(address) {
+                    let address_data = pi_state.eval(address);
                     let taint = state.load_taint_from_memory(&address_data, var.size);
                     new_state.set_register_taint(var, taint);
-                    }
                 } else {
                     new_state.set_register_taint(var, Taint::Top(var.size));
                 }
@@ -347,10 +345,9 @@ impl<'a> crate::analysis::forward_interprocedural_fixpoint::Context<'a> for Cont
                 } else if let Some(pi_state) =
                     self.get_current_pointer_inference_state(state, &def.tid)
                 {
-                    if let Ok(address_data) = pi_state.eval(address) {
+                    let address_data = pi_state.eval(address);
                     let taint = state.eval(value);
                     new_state.save_taint_to_memory(&address_data, taint);
-                    }
                 } else {
                     // We lost all knowledge about memory pointers.
                     // We delete all memory taint to reduce false positives.

src/cwe_checker_lib/src/checkers/cwe_476/state.rs

@@ -101,13 +101,12 @@ impl State {
                     if let Some(pi_state) = pi_state {
                         let address_exp =
                             Expression::Var(stack_pointer_register.clone()).plus_const(*offset);
-                        if let Ok(address) = pi_state.eval(&address_exp) {
+                        let address = pi_state.eval(&address_exp);
                         state.save_taint_to_memory(&address, Taint::Tainted(*size));
                     }
                 }
             }
         }
-        }
         state
     }
 
@@ -369,12 +368,13 @@ impl State {
             }
             memory.push((format!("{}", tid), Value::Object(Map::from_iter(elements))));
         }
-        let mut state_map = Vec::new();
-        state_map.push((
+        let state_map = vec![
+            (
                 "register".to_string(),
                 Value::Object(Map::from_iter(register)),
-        ));
-        state_map.push(("memory".to_string(), Value::Object(Map::from_iter(memory))));
+            ),
+            ("memory".to_string(), Value::Object(Map::from_iter(memory))),
+        ];
 
         Value::Object(Map::from_iter(state_map))
     }
@@ -477,7 +477,7 @@ mod tests {
         assert_eq!(state.register_taint.get(&register("RSP")), None);
         let address = Expression::Var(register("RSP"));
         assert_eq!(
-            state.load_taint_from_memory(&pi_state.eval(&address).unwrap(), ByteSize::new(8)),
+            state.load_taint_from_memory(&pi_state.eval(&address), ByteSize::new(8)),
             taint
         );
     }

src/cwe_checker_lib/src/checkers/cwe_78/context/mod.rs

@@ -262,10 +262,9 @@ impl<'a> Context<'a> {
         {
             let address_exp =
                 Expression::Var(self.project.stack_pointer_register.clone()).plus_const(offset);
-            if let Ok(address) = pi_state.eval(&address_exp) {
+            let address = pi_state.eval(&address_exp);
             new_state.save_taint_to_memory(&address, Taint::Tainted(size));
         }
-        }
         new_state
     }
 

src/cwe_checker_lib/src/checkers/cwe_78/context/tests.rs

@@ -467,13 +467,10 @@ fn creating_pi_def_map() {
 
     for (def_tid, pi_state) in pi_def_map.iter() {
         if *def_tid == def1 {
-            assert_eq!(
-                pi_state.get_register(&rdi_reg).unwrap(),
-                Data::new_top(rdi_reg.size)
-            );
+            assert_eq!(pi_state.get_register(&rdi_reg), Data::new_top(rdi_reg.size));
         } else if *def_tid == def2 {
             assert_eq!(
-                pi_state.get_register(&rdi_reg).unwrap(),
+                pi_state.get_register(&rdi_reg),
                 Data::Pointer(PointerDomain::new(stack_id.clone(), bv(-8)))
             );
         }

src/cwe_checker_lib/src/checkers/cwe_78/state/mod.rs

@@ -113,13 +113,12 @@ impl State {
                     if let Some(pi_state) = pi_state {
                         let address_exp =
                             Expression::Var(stack_pointer_register.clone()).plus_const(*offset);
-                        if let Ok(address) = pi_state.eval(&address_exp) {
+                        let address = pi_state.eval(&address_exp);
                         state.save_taint_to_memory(&address, Taint::Tainted(*size));
                     }
                 }
             }
         }
-        }
         state
     }
 
@@ -208,12 +207,11 @@ impl State {
             Expression::BinOp { .. } => {
                 if let Some(pid_map) = self.pi_def_map.as_ref() {
                     if let Some(pi_state) = pid_map.get(def_tid) {
-                        if let Ok(address) = pi_state.get_register(result) {
+                        let address = pi_state.get_register(result);
                         self.save_taint_to_memory(&address, Taint::Tainted(result.size));
                     }
                 }
             }
-            }
             Expression::UnOp { arg, .. }
             | Expression::Cast { arg, .. }
             | Expression::Subpiece { arg, .. } => {
@@ -233,7 +231,7 @@ impl State {
     ) {
         if let Some(pid_map) = self.pi_def_map.as_ref() {
             if let Some(pi_state) = pid_map.get(def_tid) {
-                if let Ok(address) = pi_state.eval(target) {
+                let address = pi_state.eval(target);
                 if self.check_if_address_points_to_taint(address.clone(), &pi_state) {
                     self.taint_def_input_register(value, stack_pointer_register, def_tid);
                     self.remove_mem_taint_at_target(&address);
@@ -241,7 +239,6 @@ impl State {
             }
         }
     }
-    }
 
     /// Taints all input register of an expression.
     pub fn taint_def_input_register(
@@ -277,14 +274,13 @@ impl State {
         if var.name == stack_pointer_register.name {
             if let Some(pid_map) = self.pi_def_map.as_ref() {
                 if let Some(pi_state) = pid_map.get(def_tid) {
-                    if let Ok(address) = pi_state.get_register(stack_pointer_register) {
+                    let address = pi_state.get_register(stack_pointer_register);
                     self.save_taint_to_memory(
                         &address,
                         Taint::Tainted(stack_pointer_register.size),
                     );
                 }
             }
-            }
         } else {
             self.set_register_taint(var, Taint::Tainted(var.size));
         }

src/cwe_checker_lib/src/intermediate_representation/bitvector.rs

@@ -25,11 +25,11 @@ pub trait BitvectorExtended: Sized {
     /// Returns an error for non-implemented operations (currently all float-related operations).
     fn bin_op(&self, op: BinOpType, rhs: &Self) -> Result<Self, Error>;
 
-    /// Returns `true` if adding `self` to `rhs` would result in a signed integer overflow or underflow.
-    fn signed_add_overflow_check(&self, rhs: &Self) -> bool;
+    /// Returns the result of `self + rhs` if the computation does not result in a signed integer overflow or underflow.
+    fn signed_add_overflow_checked(&self, rhs: &Self) -> Option<Self>;
 
-    /// Returns `true` if subtracting `rhs` from `self` would result in a signed integer overflow or underflow.
-    fn signed_sub_overflow_check(&self, rhs: &Self) -> bool;
+    /// Returns the result of `self - rhs` if the computation does not result in a signed integer overflow or underflow.
+    fn signed_sub_overflow_checked(&self, rhs: &Self) -> Option<Self>;
 
     /// Return the result of multiplying `self` with `rhs`
     /// and a flag that is set to `true` if the multiplication resulted in a signed integer overflow or underflow.
@@ -221,23 +221,21 @@ impl BitvectorExtended for Bitvector {
         }
     }
 
-    /// Returns `true` if adding `self` to `rhs` would result in a signed integer overflow or underflow.
-    fn signed_add_overflow_check(&self, rhs: &Self) -> bool {
+    /// Returns the result of `self + rhs` if the computation does not result in a signed integer overflow or underflow.
+    fn signed_add_overflow_checked(&self, rhs: &Self) -> Option<Self> {
         let result = self.clone().into_checked_add(rhs).unwrap();
-        if rhs.sign_bit().to_bool() {
-            self.checked_sle(&result).unwrap()
-        } else {
-            self.checked_sgt(&result).unwrap()
+        match (rhs.sign_bit().to_bool(), self.checked_sle(&result).unwrap()) {
+            (true, true) | (false, false) => None,
+            _ => Some(result),
         }
     }
 
-    /// Returns `true` if subtracting `rhs` from `self` would result in a signed integer overflow or underflow.
-    fn signed_sub_overflow_check(&self, rhs: &Self) -> bool {
+    /// Returns the result of `self - rhs` if the computation does not result in a signed integer overflow or underflow.
+    fn signed_sub_overflow_checked(&self, rhs: &Self) -> Option<Self> {
         let result = self.clone().into_checked_sub(rhs).unwrap();
-        if rhs.sign_bit().to_bool() {
-            self.checked_sge(&result).unwrap()
-        } else {
-            self.checked_slt(&result).unwrap()
+        match (rhs.sign_bit().to_bool(), self.checked_sge(&result).unwrap()) {
+            (true, true) | (false, false) => None,
+            _ => Some(result),
         }
     }
 
@@ -264,3 +262,36 @@ impl BitvectorExtended for Bitvector {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn overflow_checked_add_and_sub() {
+        let max = Bitvector::signed_max_value(ByteSize::new(8).into());
+        let min = Bitvector::signed_min_value(ByteSize::new(8).into());
+
+        assert_eq!(min.signed_add_overflow_checked(&min), None);
+        assert_eq!(
+            min.signed_add_overflow_checked(&max),
+            Some(-Bitvector::one(ByteSize::new(8).into()))
+        );
+        assert_eq!(
+            max.signed_add_overflow_checked(&min),
+            Some(-Bitvector::one(ByteSize::new(8).into()))
+        );
+        assert_eq!(max.signed_add_overflow_checked(&max), None);
+
+        assert_eq!(
+            min.signed_sub_overflow_checked(&min),
+            Some(Bitvector::zero(ByteSize::new(8).into()))
+        );
+        assert_eq!(min.signed_sub_overflow_checked(&max), None);
+        assert_eq!(max.signed_sub_overflow_checked(&min), None);
+        assert_eq!(
+            max.signed_sub_overflow_checked(&max),
+            Some(Bitvector::zero(ByteSize::new(8).into()))
+        );
+    }
+}

src/cwe_checker_lib/src/intermediate_representation/expression.rs

@@ -100,6 +100,22 @@ impl Expression {
         }
     }
 
+    /// Return an array of all input variables of the given expression.
+    /// The array may contain duplicates.
+    pub fn input_vars(&self) -> Vec<&Variable> {
+        use Expression::*;
+        match self {
+            Var(var) => vec![var],
+            Const(_) | Unknown { .. } => Vec::new(),
+            BinOp { op: _, lhs, rhs } => {
+                let mut vars = lhs.input_vars();
+                vars.append(&mut rhs.input_vars());
+                vars
+            }
+            UnOp { arg, .. } | Cast { arg, .. } | Subpiece { arg, .. } => arg.input_vars(),
+        }
+    }
+
     /// Substitute trivial BinOp-expressions with their results,
     /// e.g. substitute `a or a` with `a`.
     ///

src/cwe_checker_lib/src/intermediate_representation/expression/builder.rs

@@ -4,8 +4,7 @@ use apint::ApInt;
 #[cfg(test)]
 use super::{CastOpType, Variable};
 
-use super::{BinOpType, Expression};
-use crate::prelude::*;
+use super::*;
 
 /// ## Helper functions for building expressions
 impl Expression {
@@ -51,6 +50,15 @@ impl Expression {
         }
     }
 
+    /// Shortcut for creating unary operation expressions.
+    #[cfg(test)]
+    pub fn un_op(self, op: UnOpType) -> Expression {
+        Expression::UnOp {
+            op,
+            arg: Box::new(self),
+        }
+    }
+
     /// Shortcut for creating an `IntAdd`-expression
     pub fn plus(self, rhs: Expression) -> Expression {
         Expression::BinOp {
@@ -60,6 +68,16 @@ impl Expression {
         }
     }
 
+    /// Shortcut for creating an `IntSub`-expression
+    #[cfg(test)]
+    pub fn minus(self, rhs: Expression) -> Expression {
+        Expression::BinOp {
+            lhs: Box::new(self),
+            op: BinOpType::IntSub,
+            rhs: Box::new(rhs),
+        }
+    }
+
     /// Construct an expression that adds a constant value to the given expression.
     ///
     /// The bytesize of the value is automatically adjusted to the bytesize of the given expression.
@@ -73,4 +91,19 @@ impl Expression {
         }
         self.plus(Expression::Const(value))
     }
+
+    /// Construct an expression that subtracts a constant value from the given expression.
+    ///
+    /// The bytesize of the value is automatically adjusted to the bytesize of the given expression.
+    #[cfg(test)]
+    pub fn minus_const(self, value: i64) -> Expression {
+        let bytesize = self.bytesize();
+        let mut value = Bitvector::from_i64(value);
+        match u64::from(bytesize) {
+            size if size > 8 => value.sign_extend(bytesize).unwrap(),
+            size if size < 8 => value.truncate(bytesize).unwrap(),
+            _ => (),
+        }
+        self.minus(Expression::Const(value))
+    }
 }

src/cwe_checker_lib/src/pcode/expressions.rs

@@ -172,6 +172,7 @@ impl From<Expression> for IrExpression {
 /// Expression Opcodes as parsed from Ghidra
 #[allow(missing_docs)]
 #[allow(non_camel_case_types)]
+#[allow(clippy::upper_case_acronyms)]
 #[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Hash, Clone, Copy)]
 pub enum ExpressionType {
     COPY,

src/cwe_checker_lib/src/pcode/term.rs

@@ -49,6 +49,7 @@ pub struct Jmp {
 
 /// A jump type mnemonic.
 #[allow(missing_docs)]
+#[allow(clippy::upper_case_acronyms)]
 #[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Hash, Clone, Copy)]
 pub enum JmpType {
     BRANCH,
@@ -305,6 +306,7 @@ pub struct Arg {
 
 /// The intent (input or output) of a function argument.
 #[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Hash, Clone)]
+#[allow(clippy::upper_case_acronyms)]
 pub enum ArgIntent {
     /// The argument is an input parameter.
     INPUT,

src/cwe_checker_lib/src/utils/binary.rs

@@ -142,7 +142,8 @@ impl RuntimeMemoryImage {
         let address = address.try_to_u64().unwrap();
         for segment in self.memory_segments.iter() {
             if address >= segment.base_address
-                && address + u64::from(size) <= segment.base_address + segment.bytes.len() as u64
+                && u64::from(size) <= segment.base_address + segment.bytes.len() as u64
+                && address <= segment.base_address + segment.bytes.len() as u64 - u64::from(size)
             {
                 if segment.write_flag {
                     // The segment is writeable, thus we do not know the content at runtime.

src/cwe_checker_lib/src/utils/graph_utils.rs

@@ -43,7 +43,7 @@ pub fn is_sink_call_reachable_from_source_call(
             // and as long as the edge does not leave the function.
             match edge.weight() {
                 Edge::Block
-                | Edge::CRCallStub
+                | Edge::CrCallStub
                 | Edge::CallCombine(_)
                 | Edge::ReturnCombine(_)
                 | Edge::Jump(_, _)
@@ -53,7 +53,7 @@ pub fn is_sink_call_reachable_from_source_call(
                         worklist.push(edge.target())
                     }
                 }
-                Edge::Call(_) | Edge::CRReturnStub => (), // These edges would leave the function control flow graph.
+                Edge::Call(_) | Edge::CrReturnStub => (), // These edges would leave the function control flow graph.
             }
         }
     }