s column last step assertion

air/src/constraints/logup.rs

@@ -1,9 +1,25 @@
 use alloc::vec::Vec;
-use winter_air::TransitionConstraintDegree;
+use vm_core::{Felt, FieldElement};
+use winter_air::{Assertion, TransitionConstraintDegree};
+
+use crate::{gkr_proof::inner_product, trace::logup::S_COL_IDX};
 
 /// The number of auxiliary assertions.
 pub const NUM_AUX_ASSERTIONS: usize = 2;
 
 pub fn get_aux_transition_constraint_degrees() -> Vec<TransitionConstraintDegree> {
     todo!()
 }
+
+pub fn get_aux_assertions_last_step<E>(
+    result: &mut Vec<Assertion<E>>,
+    openings_combining_randomness: &[E],
+    openings: &[E],
+    step: usize,
+) where
+    E: FieldElement<BaseField = Felt>,
+{
+    let value = inner_product(openings_combining_randomness, openings);
+
+    result.push(Assertion::single(S_COL_IDX, step, value));
+}

air/src/gkr_verifier/sum_check_verifier/mod.rs

@@ -95,7 +95,7 @@ where
         if openings_claim.eval_point != evaluation_point {
             return Err(Error::WrongOpeningPoint);
         }
-        let query = self.final_query_builder.build_query(&openings_claim, &evaluation_point);
+        let query = self.final_query_builder.build_query(openings_claim, &evaluation_point);
 
         if self.composition_poly.evaluate(&query) != claimed_evaluation {
             Err(Error::FinalEvaluationCheckFailed)

air/src/lib.rs

@@ -199,6 +199,22 @@ impl Air for ProcessorAir {
             last_step,
         );
 
+        // Add LogUp's "s" column assertions for the last step.
+        {
+            let openings_combining_randomness = aux_rand_elements
+                .gkr_openings_combining_randomness()
+                .expect("GKR openings combining randomness not present in AuxRandElements");
+            let openings =
+                gkr_proof.expect("GKR proof not present").get_final_opening_claim().openings;
+
+            logup::get_aux_assertions_last_step(
+                &mut result,
+                openings_combining_randomness,
+                &openings,
+                last_step,
+            );
+        }
+
         result
     }