chore: Recursive verifier updates (#3452)

This work contains the following updates:

1. Previously we used only `check_circuit()` to ensure correctness of
the Honk recursive verifier circuits. This is somewhat incomplete if the
arithmetization of the circuit is Goblin Ultra Honk since
`check_circuit()` is only complete for the conventional Ultra
arithmetization and does not cover Goblin style ecc op gates or the
DataBus functionality. This PR swaps out `check_circuit` for genuine
proof construction/verification which is more time consuming but also
more robust.
2. Updates constructor of recursive verifier to take a native
verification key directly rather than requiring prior external
construction of the stdlib verification key.
3. Adds a debug only method for ensuring all selectors have the same
length.

Note: Currently the two recursive verifier test suites share a lot of
code. A follow on should potentially combine the two suites.

cpp/src/barretenberg/flavor/goblin_ultra_recursive.hpp

@@ -46,6 +46,7 @@ template <typename BuilderType> class GoblinUltraRecursive_ {
     using Commitment = typename Curve::Element;
     using CommitmentHandle = typename Curve::Element;
     using FF = typename Curve::ScalarField;
+    using NativeVerificationKey = flavor::GoblinUltra::VerificationKey;
 
     // Note(luke): Eventually this may not be needed at all
     using VerifierCommitmentKey = pcs::VerifierCommitmentKey<Curve>;
@@ -106,7 +107,7 @@ template <typename BuilderType> class GoblinUltraRecursive_ {
          * @param builder
          * @param native_key Native verification key from which to extract the precomputed commitments
          */
-        VerificationKey(CircuitBuilder* builder, const auto& native_key)
+        VerificationKey(CircuitBuilder* builder, std::shared_ptr<NativeVerificationKey> native_key)
             : VerificationKey_<GoblinUltra::PrecomputedEntities<Commitment>>(native_key->circuit_size,
                                                                              native_key->num_public_inputs)
         {

cpp/src/barretenberg/flavor/ultra_recursive.hpp

@@ -54,6 +54,7 @@ template <typename BuilderType> class UltraRecursive_ {
     using Commitment = typename Curve::Element;
     using CommitmentHandle = typename Curve::Element;
     using FF = typename Curve::ScalarField;
+    using NativeVerificationKey = flavor::Ultra::VerificationKey;
 
     // Note(luke): Eventually this may not be needed at all
     using VerifierCommitmentKey = pcs::VerifierCommitmentKey<Curve>;
@@ -250,7 +251,7 @@ template <typename BuilderType> class UltraRecursive_ {
          * @param builder
          * @param native_key Native verification key from which to extract the precomputed commitments
          */
-        VerificationKey(CircuitBuilder* builder, auto native_key)
+        VerificationKey(CircuitBuilder* builder, std::shared_ptr<NativeVerificationKey> native_key)
             : VerificationKey_<PrecomputedEntities<Commitment>>(native_key->circuit_size, native_key->num_public_inputs)
         {
             this->q_m = Commitment::from_witness(builder, native_key->q_m);

cpp/src/barretenberg/proof_system/arithmetization/arithmetization.hpp

@@ -137,7 +137,7 @@ template <typename FF_> class UltraHonk {
     SelectorType& q_elliptic() { return selectors[8]; };
     SelectorType& q_aux() { return selectors[9]; };
     SelectorType& q_lookup_type() { return selectors[10]; };
-    SelectorType& q_busread() { return this->selectors[11]; };
+    SelectorType& q_busread() { return selectors[11]; };
     SelectorType& q_poseidon2_external() { return this->selectors[12]; };
     SelectorType& q_poseidon2_internal() { return this->selectors[13]; };
 

cpp/src/barretenberg/proof_system/circuit_builder/goblin_ultra_circuit_builder.cpp

@@ -47,7 +47,7 @@ template <typename FF> void GoblinUltraCircuitBuilder_<FF>::add_gates_to_ensure_
     this->w_l.emplace_back(public_calldata[read_idx]);        // populate with value of calldata at read index
     this->w_r.emplace_back(this->add_variable(FF(read_idx))); // populate with read index as witness
     calldata_read_counts[read_idx]++;                         // increment read count at read index
-    q_busread.emplace_back(1);                                // read selector on
+    q_busread().emplace_back(1);                              // read selector on
 
     // populate all other components with zero
     this->w_o.emplace_back(this->zero_idx);
@@ -84,7 +84,7 @@ template <typename FF> void GoblinUltraCircuitBuilder_<FF>::add_gates_to_ensure_
     this->q_lookup_type.emplace_back(0);
     this->q_elliptic.emplace_back(0);
     this->q_aux.emplace_back(0);
-    this->q_busread.emplace_back(0);
+    this->q_busread().emplace_back(0);
     this->q_poseidon2_external.emplace_back(1);
     this->q_poseidon2_internal.emplace_back(1);
 
@@ -106,7 +106,7 @@ template <typename FF> void GoblinUltraCircuitBuilder_<FF>::add_gates_to_ensure_
     this->q_lookup_type.emplace_back(0);
     this->q_elliptic.emplace_back(0);
     this->q_aux.emplace_back(0);
-    this->q_busread.emplace_back(0);
+    this->q_busread().emplace_back(0);
     this->q_poseidon2_external.emplace_back(0);
     this->q_poseidon2_internal.emplace_back(0);
 
@@ -264,7 +264,7 @@ void GoblinUltraCircuitBuilder_<FF>::create_poseidon2_external_gate(const poseid
     this->q_lookup_type.emplace_back(0);
     this->q_elliptic.emplace_back(0);
     this->q_aux.emplace_back(0);
-    this->q_busread.emplace_back(0);
+    this->q_busread().emplace_back(0);
     this->q_poseidon2_external.emplace_back(1);
     this->q_poseidon2_internal.emplace_back(0);
     ++this->num_gates;
@@ -288,7 +288,7 @@ void GoblinUltraCircuitBuilder_<FF>::create_poseidon2_internal_gate(const poseid
     this->q_lookup_type.emplace_back(0);
     this->q_elliptic.emplace_back(0);
     this->q_aux.emplace_back(0);
-    this->q_busread.emplace_back(0);
+    this->q_busread().emplace_back(0);
     this->q_poseidon2_external.emplace_back(0);
     this->q_poseidon2_internal.emplace_back(1);
     ++this->num_gates;

cpp/src/barretenberg/proof_system/circuit_builder/goblin_ultra_circuit_builder.hpp

@@ -42,7 +42,7 @@ template <typename FF> class GoblinUltraCircuitBuilder_ : public UltraCircuitBui
     WireVector& ecc_op_wire_3 = std::get<2>(ecc_op_wires);
     WireVector& ecc_op_wire_4 = std::get<3>(ecc_op_wires);
 
-    SelectorVector& q_busread = this->selectors.q_busread();
+    SelectorVector& q_busread() { return this->selectors.q_busread(); };
     SelectorVector& q_poseidon2_external = this->selectors.q_poseidon2_external();
     SelectorVector& q_poseidon2_internal = this->selectors.q_poseidon2_internal();
 

cpp/src/barretenberg/proof_system/circuit_builder/ultra_circuit_builder.cpp

@@ -80,6 +80,7 @@ void UltraCircuitBuilder_<Arithmetization>::add_gates_to_ensure_all_polys_are_no
     q_elliptic.emplace_back(1);
     q_aux.emplace_back(1);
     selectors.pad_additional();
+    check_selector_length_consistency();
     ++this->num_gates;
 
     // Some relations depend on wire shifts so we add another gate with
@@ -140,6 +141,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_add_gate(const add_triple_<FF
     q_elliptic.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
     ++this->num_gates;
 }
 
@@ -172,6 +174,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_big_add_gate(const add_quad_<
     q_elliptic.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
     ++this->num_gates;
 }
 
@@ -266,6 +269,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_big_mul_gate(const mul_quad_<
     q_elliptic.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
     ++this->num_gates;
 }
 
@@ -292,6 +296,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_balanced_add_gate(const add_q
     q_elliptic.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
     ++this->num_gates;
     // Why 3? TODO: return to this
     // The purpose of this gate is to do enable lazy 32-bit addition.
@@ -334,6 +339,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_mul_gate(const mul_triple_<FF
     q_elliptic.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
     ++this->num_gates;
 }
 /**
@@ -363,6 +369,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_bool_gate(const uint32_t vari
     q_elliptic.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
     ++this->num_gates;
 }
 
@@ -394,6 +401,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_poly_gate(const poly_triple_<
     q_elliptic.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
     ++this->num_gates;
 }
 
@@ -448,6 +456,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_ecc_add_gate(const ecc_add_ga
         q_elliptic.emplace_back(1);
         q_aux.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         ++this->num_gates;
     }
     w_l.emplace_back(in.x2);
@@ -466,6 +475,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_ecc_add_gate(const ecc_add_ga
     q_elliptic.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
     ++this->num_gates;
 }
 
@@ -512,6 +522,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_ecc_dbl_gate(const ecc_dbl_ga
         q_lookup_type.emplace_back(0);
         q_aux.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         ++this->num_gates;
     }
 
@@ -531,6 +542,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_ecc_dbl_gate(const ecc_dbl_ga
     q_elliptic.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
     ++this->num_gates;
 }
 
@@ -561,6 +573,7 @@ void UltraCircuitBuilder_<Arithmetization>::fix_witness(const uint32_t witness_i
     q_elliptic.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
     ++this->num_gates;
 }
 
@@ -636,6 +649,7 @@ plookup::ReadData<uint32_t> UltraCircuitBuilder_<Arithmetization>::create_gates_
         q_elliptic.emplace_back(0);
         q_aux.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         ++this->num_gates;
     }
     return read_data;
@@ -945,6 +959,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_sort_constraint(const std::ve
         q_lookup_type.emplace_back(0);
         q_aux.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
     }
     // dummy gate needed because of sort widget's check of next row
     w_l.emplace_back(variable_index[variable_index.size() - 1]);
@@ -964,6 +979,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_sort_constraint(const std::ve
     q_lookup_type.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
 }
 
 // useful to put variables in the witness that aren't already used - e.g. the dummy variables of the range constraint in
@@ -998,6 +1014,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_dummy_constraints(const std::
         q_lookup_type.emplace_back(0);
         q_aux.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
     }
 }
 
@@ -1029,6 +1046,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_sort_constraint_with_edges(
     q_lookup_type.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
     // enforce range check for middle rows
     for (size_t i = gate_width; i < variable_index.size() - gate_width; i += gate_width) {
 
@@ -1049,6 +1067,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_sort_constraint_with_edges(
         q_lookup_type.emplace_back(0);
         q_aux.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
     }
     // enforce range checks of last row and ending at end
     if (variable_index.size() > gate_width) {
@@ -1069,6 +1088,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_sort_constraint_with_edges(
         q_lookup_type.emplace_back(0);
         q_aux.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
     }
 
     // dummy gate needed because of sort widget's check of next row
@@ -1090,6 +1110,7 @@ void UltraCircuitBuilder_<Arithmetization>::create_sort_constraint_with_edges(
     q_lookup_type.emplace_back(0);
     q_aux.emplace_back(0);
     selectors.pad_additional();
+    check_selector_length_consistency();
 }
 
 // range constraint a value by decomposing it into limbs whose size should be the default range constraint size
@@ -1206,6 +1227,7 @@ void UltraCircuitBuilder_<Arithmetization>::apply_aux_selectors(const AUX_SELECT
         q_c.emplace_back(0);
         q_arith.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         break;
     }
     case AUX_SELECTORS::LIMB_ACCUMULATE_2: {
@@ -1217,6 +1239,7 @@ void UltraCircuitBuilder_<Arithmetization>::apply_aux_selectors(const AUX_SELECT
         q_c.emplace_back(0);
         q_arith.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         break;
     }
     case AUX_SELECTORS::NON_NATIVE_FIELD_1: {
@@ -1228,6 +1251,7 @@ void UltraCircuitBuilder_<Arithmetization>::apply_aux_selectors(const AUX_SELECT
         q_c.emplace_back(0);
         q_arith.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         break;
     }
     case AUX_SELECTORS::NON_NATIVE_FIELD_2: {
@@ -1239,6 +1263,7 @@ void UltraCircuitBuilder_<Arithmetization>::apply_aux_selectors(const AUX_SELECT
         q_c.emplace_back(0);
         q_arith.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         break;
     }
     case AUX_SELECTORS::NON_NATIVE_FIELD_3: {
@@ -1250,6 +1275,7 @@ void UltraCircuitBuilder_<Arithmetization>::apply_aux_selectors(const AUX_SELECT
         q_c.emplace_back(0);
         q_arith.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         break;
     }
     case AUX_SELECTORS::ROM_CONSISTENCY_CHECK: {
@@ -1265,6 +1291,7 @@ void UltraCircuitBuilder_<Arithmetization>::apply_aux_selectors(const AUX_SELECT
         q_c.emplace_back(0);
         q_arith.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         break;
     }
     case AUX_SELECTORS::RAM_CONSISTENCY_CHECK: {
@@ -1281,6 +1308,7 @@ void UltraCircuitBuilder_<Arithmetization>::apply_aux_selectors(const AUX_SELECT
         q_c.emplace_back(0);
         q_arith.emplace_back(1);
         selectors.pad_additional();
+        check_selector_length_consistency();
         break;
     }
     case AUX_SELECTORS::RAM_TIMESTAMP_CHECK: {
@@ -1294,6 +1322,7 @@ void UltraCircuitBuilder_<Arithmetization>::apply_aux_selectors(const AUX_SELECT
         q_c.emplace_back(0);
         q_arith.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         break;
     }
     case AUX_SELECTORS::ROM_READ: {
@@ -1308,6 +1337,7 @@ void UltraCircuitBuilder_<Arithmetization>::apply_aux_selectors(const AUX_SELECT
         q_c.emplace_back(0); // read/write flag stored in q_c
         q_arith.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         break;
     }
     case AUX_SELECTORS::RAM_READ: {
@@ -1322,6 +1352,7 @@ void UltraCircuitBuilder_<Arithmetization>::apply_aux_selectors(const AUX_SELECT
         q_c.emplace_back(0); // read/write flag stored in q_c
         q_arith.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         break;
     }
     case AUX_SELECTORS::RAM_WRITE: {
@@ -1336,6 +1367,7 @@ void UltraCircuitBuilder_<Arithmetization>::apply_aux_selectors(const AUX_SELECT
         q_c.emplace_back(1); // read/write flag stored in q_c
         q_arith.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         break;
     }
     default: {
@@ -1347,6 +1379,7 @@ void UltraCircuitBuilder_<Arithmetization>::apply_aux_selectors(const AUX_SELECT
         q_c.emplace_back(0);
         q_arith.emplace_back(0);
         selectors.pad_additional();
+        check_selector_length_consistency();
         break;
     }
     }
@@ -1869,6 +1902,7 @@ std::array<uint32_t, 5> UltraCircuitBuilder_<Arithmetization>::evaluate_non_nati
         q_aux.emplace_back(0);
         selectors.pad_additional();
     }
+    check_selector_length_consistency();
 
     this->num_gates += 4;
     return std::array<uint32_t, 5>{
@@ -1991,6 +2025,7 @@ std::array<uint32_t, 5> UltraCircuitBuilder_<Arithmetization>::evaluate_non_nati
         q_aux.emplace_back(0);
         selectors.pad_additional();
     }
+    check_selector_length_consistency();
 
     this->num_gates += 4;
     return std::array<uint32_t, 5>{