Refactor Context::debug_info to a struct.

crates/cairo_verifier/src/circuit_analysis.rs

@@ -3,7 +3,7 @@
 use std::ops::Deref;
 
 use circuits::circuit::{Add, BlakeGGate, Circuit, M31ToU32, Mul, PointwiseMul, Sub, TripleXor};
-use circuits::context::Var;
+use circuits::context::DebugInfo;
 use circuits::ivalue::{IValue, qm31_from_u32s};
 use hashbrown::{HashMap, HashSet};
 use num_traits::{One, Zero};
@@ -545,7 +545,7 @@ fn validate_logup_summand(
 }
 
 /// Analyzes the circuit and writes the classified logup-sum summands to `summands.txt`.
-pub fn analyze(circuit: &Circuit, debug_info: &HashMap<String, Var>) {
+pub fn analyze(circuit: &Circuit, debug_info: &DebugInfo) {
     let c = build_analysis(circuit);
     let const_values = propagate_constants(&c);
 
@@ -557,16 +557,16 @@ pub fn analyze(circuit: &Circuit, debug_info: &HashMap<String, Var>) {
     let ground = Ground { c: &c, const_values: &const_values, idiom: &idiom };
 
     // Seed each challenge's `grounded` cache with its dependency closure.
-    let int_z = debug_info["interaction_z"].idx;
+    let int_z = debug_info.vars["interaction_z"].idx;
     let mut int_z_cache = ground.init_grounding_cache(int_z);
 
-    let composition_coef = debug_info["composition_polynomial_coeff"].idx;
+    let composition_coef = debug_info.vars["composition_polynomial_coeff"].idx;
     let mut composition_coef_cache = ground.init_grounding_cache(composition_coef);
 
-    let logup_sum = debug_info["logup_sum"].idx;
+    let logup_sum = debug_info.vars["logup_sum"].idx;
     let summands = find_summands(&c, &const_values, logup_sum);
 
-    let composition_eval = debug_info["composition_eval"].idx;
+    let composition_eval = debug_info.vars["composition_eval"].idx;
     let composition_vars = add_mul_cone(&c, &const_values, composition_eval);
 
     for s in summands {

crates/circuits/src/context.rs

@@ -86,8 +86,15 @@ pub struct Context<Value: IValue> {
     /// Debug only. If true, equality is asserted when adding the `eq` gate; if false, no
     /// assertion is made during construction and equality can be checked later at validation.
     pub assert_eq_on_eval: bool,
-    /// Debug only. A map from variable name to the corresponding [Var].
-    pub debug_info: HashMap<String, Var>,
+    /// Debug only. Named variables for testing purposes.
+    pub debug_info: DebugInfo,
+}
+
+/// Named variables for testing purposes.
+#[derive(Default)]
+pub struct DebugInfo {
+    /// A map from name to the corresponding [Var].
+    pub vars: HashMap<String, Var>,
 }
 
 impl<Value: IValue> Context<Value> {
@@ -264,7 +271,7 @@ impl<Value: IValue> Default for Context<Value> {
             guessed_vars: Some(vec![]),
             reserved_vars: vec![],
             assert_eq_on_eval: false,
-            debug_info: HashMap::new(),
+            debug_info: DebugInfo::default(),
         };
         // Register zero, one, and u as the first constants.
         res.constant(QM31::zero());

crates/stark_verifier/src/verify.rs

@@ -42,7 +42,7 @@ pub fn validate_logup_sum(
     for claimed_sum in claimed_sums {
         logup_sum = eval!(context, (logup_sum) + (*claimed_sum));
     }
-    context.debug_info.insert("logup_sum".into(), logup_sum);
+    context.debug_info.vars.insert("logup_sum".into(), logup_sum);
     eq(context, logup_sum, context.zero());
 }
 
@@ -89,8 +89,8 @@ pub fn verify<Value: IValue>(
     channel.pow(context, config.n_interaction_pow_bits, proof.interaction_pow_nonce);
     // Pick the interaction elements.
     let [interaction_z, interaction_alpha] = channel.draw_two_qm31s(context);
-    context.debug_info.insert("interaction_z".into(), interaction_z);
-    context.debug_info.insert("interaction_alpha".into(), interaction_alpha);
+    context.debug_info.vars.insert("interaction_z".into(), interaction_z);
+    context.debug_info.vars.insert("interaction_alpha".into(), interaction_alpha);
 
     let public_logup_sum = statement.public_logup_sum(context, [interaction_z, interaction_alpha]);
     validate_logup_sum(context, public_logup_sum, &proof.claimed_sums);
@@ -100,7 +100,10 @@ pub fn verify<Value: IValue>(
 
     // Draw a random QM31 coefficient for the composition polynomial.
     let composition_polynomial_coeff = channel.draw_qm31(context);
-    context.debug_info.insert("composition_polynomial_coeff".into(), composition_polynomial_coeff);
+    context
+        .debug_info
+        .vars
+        .insert("composition_polynomial_coeff".into(), composition_polynomial_coeff);
 
     channel.mix_commitment(context, &proof.composition_polynomial_root);
 
@@ -154,7 +157,7 @@ pub fn verify<Value: IValue>(
             n_instances_bits: &component_sizes_bits,
         },
     );
-    context.debug_info.insert("composition_eval".into(), composition_eval);
+    context.debug_info.vars.insert("composition_eval".into(), composition_eval);
     let expected_composition_eval = extract_expected_composition_eval(
         context,
         &proof.composition_eval_at_oods,