Remove (almost) all dead code

ceno_emul/src/rv32im.rs

@@ -88,7 +88,6 @@ pub struct Emulator {
 }
 
 #[derive(Debug)]
-#[allow(dead_code)]
 pub enum TrapCause {
     InstructionAddressMisaligned,
     InstructionAccessFault,

ceno_zkvm/src/expression/monomial.rs

@@ -136,11 +136,6 @@ impl<E: ExtensionField> PartialOrd for Expression<E> {
     }
 }
 
-#[allow(dead_code)]
-fn cmp_field<F: SmallField>(a: &F, b: &F) -> Ordering {
-    a.to_canonical_u64().cmp(&b.to_canonical_u64())
-}
-
 fn cmp_ext<E: ExtensionField>(a: &E, b: &E) -> Ordering {
     let a = a.as_bases().iter().map(|f| f.to_canonical_u64());
     let b = b.as_bases().iter().map(|f| f.to_canonical_u64());

ceno_zkvm/src/instructions/riscv/b_insn.rs

@@ -1,5 +1,3 @@
-#![allow(dead_code)] // TODO: remove after BLT, BEQ, …
-
 use ceno_emul::{InsnKind, StepRecord};
 use ff_ext::ExtensionField;
 

ceno_zkvm/src/instructions/riscv/memory/store.rs

@@ -38,8 +38,7 @@ impl RIVInstruction for SWOp {
     const INST_KIND: InsnKind = InsnKind::SW;
 }
 
-// this is actually used in test
-#[allow(dead_code)]
+#[cfg(test)]
 pub type SwInstruction<E> = StoreInstruction<E, SWOp, 2>;
 
 pub struct SHOp;
@@ -48,8 +47,7 @@ impl RIVInstruction for SHOp {
     const INST_KIND: InsnKind = InsnKind::SH;
 }
 
-// this is actually used in test
-#[allow(dead_code)]
+#[cfg(test)]
 pub type ShInstruction<E> = StoreInstruction<E, SHOp, 1>;
 
 pub struct SBOp;
@@ -58,8 +56,7 @@ impl RIVInstruction for SBOp {
     const INST_KIND: InsnKind = InsnKind::SB;
 }
 
-// this is actually used in test
-#[allow(dead_code)]
+#[cfg(test)]
 pub type SbInstruction<E> = StoreInstruction<E, SBOp, 0>;
 
 impl<E: ExtensionField, I: RIVInstruction, const N_ZEROS: usize> Instruction<E>

ceno_zkvm/src/instructions/riscv/shift.rs

@@ -31,14 +31,16 @@ pub struct ShiftConfig<E: ExtensionField> {
 
 pub struct ShiftLogicalInstruction<E, I>(PhantomData<(E, I)>);
 
-#[allow(dead_code)]
+#[cfg(test)]
 struct SllOp;
+#[cfg(test)]
 impl RIVInstruction for SllOp {
     const INST_KIND: InsnKind = InsnKind::SLL;
 }
 
-#[allow(dead_code)]
+#[cfg(test)]
 struct SrlOp;
+#[cfg(test)]
 impl RIVInstruction for SrlOp {
     const INST_KIND: InsnKind = InsnKind::SRL;
 }

ceno_zkvm/src/instructions/riscv/slt.rs

@@ -17,7 +17,7 @@ pub struct SltConfig<E: ExtensionField> {
 
     rs1_read: UInt<E>,
     rs2_read: UInt<E>,
-    #[allow(dead_code)]
+    #[cfg_attr(not(test), allow(dead_code))]
     rd_written: UInt<E>,
 
     signed_lt: SignedLtConfig,

ceno_zkvm/src/instructions/riscv/sltu.rs

@@ -21,7 +21,7 @@ pub struct ArithConfig<E: ExtensionField> {
 
     rs1_read: UInt<E>,
     rs2_read: UInt<E>,
-    #[allow(dead_code)]
+    #[cfg_attr(not(test), allow(dead_code))]
     rd_written: UInt<E>,
 
     is_lt: IsLtConfig,

ceno_zkvm/src/scheme/mock_prover.rs

@@ -701,10 +701,12 @@ mod tests {
     use multilinear_extensions::mle::{IntoMLE, IntoMLEs};
 
     #[derive(Debug)]
-    #[allow(dead_code)]
     struct AssertZeroCircuit {
+        #[allow(dead_code)]
         pub a: WitIn,
+        #[allow(dead_code)]
         pub b: WitIn,
+        #[allow(dead_code)]
         pub c: WitIn,
     }
 
@@ -832,7 +834,6 @@ mod tests {
         assert_eq!(err[0].inst_id(), 0);
     }
 
-    #[allow(dead_code)]
     #[derive(Debug)]
     struct AssertLtCircuit {
         pub a: WitIn,

ceno_zkvm/src/scheme/utils.rs

@@ -352,7 +352,7 @@ pub(crate) fn wit_infer_by_expr<'a, E: ExtensionField, const N: usize>(
     )
 }
 
-#[allow(dead_code)]
+#[cfg(test)]
 pub(crate) fn eval_by_expr<E: ExtensionField>(
     witnesses: &[E],
     challenges: &[E],
@@ -361,7 +361,7 @@ pub(crate) fn eval_by_expr<E: ExtensionField>(
     eval_by_expr_with_fixed(&[], witnesses, challenges, expr)
 }
 
-#[allow(dead_code)]
+#[cfg(test)]
 pub(crate) fn eval_by_expr_with_fixed<E: ExtensionField>(
     fixed: &[E],
     witnesses: &[E],

ceno_zkvm/src/uint.rs

@@ -637,7 +637,6 @@ impl ValueMul {
 
 #[derive(Clone)]
 pub struct Value<'a, T: Into<u64> + From<u32> + Copy + Default> {
-    #[allow(dead_code)]
     val: T,
     pub limbs: Cow<'a, [u16]>,
 }

ceno_zkvm/src/utils.rs

@@ -5,13 +5,6 @@ use itertools::Itertools;
 use multilinear_extensions::util::max_usable_threads;
 use transcript::Transcript;
 
-/// convert ext field element to u64, assume it is inside the range
-#[allow(dead_code)]
-pub fn ext_to_u64<E: ExtensionField>(x: &E) -> u64 {
-    let bases = x.as_bases();
-    bases[0].to_canonical_u64()
-}
-
 pub fn i64_to_base<F: SmallField>(x: i64) -> F {
     if x >= 0 {
         F::from(x as u64)
@@ -20,20 +13,6 @@ pub fn i64_to_base<F: SmallField>(x: i64) -> F {
     }
 }
 
-/// This is helper function to convert witness of u8 limb into u16 limb
-/// TODO: need a better way to keep consistency of LIMB_BITS
-#[allow(dead_code)]
-pub fn limb_u8_to_u16(input: &[u8]) -> Vec<u16> {
-    input
-        .chunks(2)
-        .map(|chunk| {
-            let low = chunk[0] as u16;
-            let high = if chunk.len() > 1 { chunk[1] as u16 } else { 0 };
-            high * 256 + low
-        })
-        .collect()
-}
-
 pub fn split_to_u8<T: From<u8>>(value: u32) -> Vec<T> {
     (0..(u32::BITS / 8))
         .scan(value, |acc, _| {
@@ -72,15 +51,6 @@ pub(crate) fn add_one_to_big_num<F: Field>(limb_modulo: F, limbs: &[F]) -> Vec<F
     result
 }
 
-#[allow(dead_code)]
-pub(crate) fn i64_to_base_field<E: ExtensionField>(x: i64) -> E::BaseField {
-    if x >= 0 {
-        E::BaseField::from(x as u64)
-    } else {
-        -E::BaseField::from((-x) as u64)
-    }
-}
-
 /// derive challenge from transcript and return all pows result
 pub fn get_challenge_pows<E: ExtensionField>(
     size: usize,

ceno_zkvm/src/witness.rs

@@ -133,7 +133,6 @@ pub struct LkMultiplicity {
     multiplicity: Arc<ThreadLocal<RefCell<[HashMap<u64, usize>; mem::variant_count::<ROMType>()]>>>,
 }
 
-#[allow(dead_code)]
 impl LkMultiplicity {
     /// assert within range
     #[inline(always)]

gkr-graph/src/structs.rs

@@ -45,7 +45,7 @@ pub enum PredType {
 #[derive(Clone, Debug)]
 pub struct CircuitNode<E: ExtensionField> {
     pub(crate) id: usize,
-    // TODO(Matthias): See whether we can remove this field.
+    // Note: only for debug output.
     #[allow(dead_code)]
     pub(crate) label: &'static str,
     pub(crate) circuit: Arc<Circuit<E>>,

gkr/src/circuit.rs

@@ -42,14 +42,6 @@ where
         in_eq_vec: &[E],
         challenges: &HashMap<ChallengeConst, Vec<E::BaseField>>,
     ) -> E;
-    // TODO(Matthias, by 2024-11-01): review whether we need this function after all.
-    #[allow(dead_code)]
-    fn fix_out_variables(
-        &self,
-        in_size: usize,
-        out_eq_vec: &[E],
-        challenges: &HashMap<ChallengeConst, Vec<E::BaseField>>,
-    ) -> Vec<E>;
 }
 
 impl<E> EvaluateGate1In<E> for &[Gate1In<ConstantType<E>>]
@@ -68,18 +60,6 @@ where
                 * gate.scalar.eval(challenges)
         })
     }
-    fn fix_out_variables(
-        &self,
-        in_size: usize,
-        out_eq_vec: &[E],
-        challenges: &HashMap<ChallengeConst, Vec<E::BaseField>>,
-    ) -> Vec<E> {
-        let mut ans = vec![E::ZERO; in_size];
-        for gate in self.iter() {
-            ans[gate.idx_in[0]] += out_eq_vec[gate.idx_out] * gate.scalar.eval(challenges);
-        }
-        ans
-    }
 }
 
 pub trait EvaluateGate2In<E>

multilinear_extensions/src/virtual_poly.rs

@@ -8,7 +8,7 @@ use ark_std::{end_timer, iterable::Iterable, rand::Rng, start_timer};
 use ff::{Field, PrimeField};
 use ff_ext::ExtensionField;
 use rayon::{
-    iter::{IntoParallelIterator, IntoParallelRefIterator},
+    iter::IntoParallelIterator,
     prelude::{IndexedParallelIterator, ParallelIterator},
     slice::ParallelSliceMut,
 };
@@ -478,37 +478,6 @@ pub fn build_eq_x_r_vec<E: ExtensionField>(r: &[E]) -> Vec<E> {
     }
 }
 
-/// A helper function to build eq(x, r) via dynamic programing tricks.
-/// This function takes 2^num_var iterations, and per iteration with 1 multiplication.
-#[allow(dead_code)]
-fn build_eq_x_r_helper<E: ExtensionField>(r: &[E], buf: &mut [Vec<E>; 2]) {
-    buf[0][0] = E::ONE;
-    if r.is_empty() {
-        buf[0].resize(1, E::ZERO);
-        return;
-    }
-    for (i, r) in r.iter().rev().enumerate() {
-        let [current, next] = buf;
-        let (cur_size, next_size) = (1 << i, 1 << (i + 1));
-        // suppose at the previous step we processed buf [0..size]
-        // for the current step we are populating new buf[0..2*size]
-        // for j travese 0..size
-        // buf[2*j + 1] = r * buf[j]
-        // buf[2*j] = (1 - r) * buf[j]
-        current[0..cur_size]
-            .par_iter()
-            .zip_eq(next[0..next_size].par_chunks_mut(2))
-            .with_min_len(64)
-            .for_each(|(prev_val, next_vals)| {
-                assert!(next_vals.len() == 2);
-                let tmp = *r * prev_val;
-                next_vals[1] = tmp;
-                next_vals[0] = *prev_val - tmp;
-            });
-        buf.swap(0, 1); // swap rolling buffer
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use crate::virtual_poly::{build_eq_x_r_vec, build_eq_x_r_vec_sequential};

singer/src/scheme.rs

@@ -1,30 +1,15 @@
 use ff_ext::ExtensionField;
 
 // TODO: to be changed to a real PCS scheme.
-type BatchedPCSProof<F> = Vec<Vec<F>>;
-type Commitment<F> = Vec<F>;
 
 pub mod prover;
 pub mod verifier;
 
-pub struct CommitPhaseProof<E: ExtensionField> {
-    // TODO(Matthias): Check whether we need this field.
-    #[allow(dead_code)]
-    commitments: Vec<Commitment<E>>,
-}
-
 pub type GKRGraphProof<F> = gkr_graph::structs::IOPProof<F>;
 pub type GKRGraphProverState<F> = gkr_graph::structs::IOPProverState<F>;
 pub type GKRGraphVerifierState<F> = gkr_graph::structs::IOPVerifierState<F>;
 
-pub struct OpenPhaseProof<E: ExtensionField> {
-    // TODO(Matthias): Check whether we need this field.
-    #[allow(dead_code)]
-    pcs_proof: BatchedPCSProof<E>,
-}
-
 pub struct SingerProof<E: ExtensionField> {
-    // commitment_phase_proof: CommitPhaseProof<F>,
+    // TODO: restore and implement `commitment_phase_proof` and `open_phase_proof`
     gkr_phase_proof: GKRGraphProof<E>,
-    // open_phase_proof: OpenPhaseProof<F>,
 }

singer/src/utils.rs

@@ -3,16 +3,6 @@ use ff_ext::ExtensionField;
 use itertools::izip;
 use simple_frontend::structs::{CellId, CircuitBuilder};
 
-// TODO(Matthias): Check whether we need this function.
-#[allow(dead_code)]
-pub(crate) fn i64_to_base_field<E: ExtensionField>(x: i64) -> E::BaseField {
-    if x >= 0 {
-        E::BaseField::from(x as u64)
-    } else {
-        -E::BaseField::from((-x) as u64)
-    }
-}
-
 pub(crate) fn add_assign_each_cell<E: ExtensionField>(
     circuit_builder: &mut CircuitBuilder<E>,
     dest: &[CellId],

sumcheck/src/structs.rs

@@ -14,7 +14,6 @@ pub struct IOPProof<E: ExtensionField> {
     pub proofs: Vec<IOPProverMessage<E>>,
 }
 impl<E: ExtensionField> IOPProof<E> {
-    #[allow(dead_code)]
     pub fn extract_sum(&self) -> E {
         self.proofs[0].evaluations[0] + self.proofs[0].evaluations[1]
     }