feat: implementation for bigint opcodes (AztecProtocol#4288)

This PR implements bigint opcodes in barretenberg. It mainly implements a wrapper around the bigint ids that Noir uses, through a map id -> bigfield However, because you can use custom bigint modulus in Noir, and because modulus is hardcoded through template types in Barretenberg, the code (and the id->bigfield map) is duplicated for the 6 modulus type (base and scalar fields for bn254, secp256r1/k1) --------- Co-authored-by: ludamad <adam@aztecprotocol.com> Co-authored-by: kevaundray <kevtheappdev@gmail.com>
Swoir · Feb 2, 2024 · 2c9c408 · 2c9c408
1 parent 7eb279c
commit 2c9c408
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Showing 12 changed files with 982 additions and 51 deletions.
diff --git a/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_format.cpp b/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_format.cpp
@@ -1,10 +1,14 @@
 #include "acir_format.hpp"
 #include "barretenberg/common/log.hpp"
+#include "barretenberg/dsl/acir_format/bigint_constraint.hpp"
 #include "barretenberg/proof_system/circuit_builder/ultra_circuit_builder.hpp"
 #include <cstddef>
 
 namespace acir_format {
 
+template class DSLBigInts<UltraCircuitBuilder>;
+template class DSLBigInts<GoblinUltraCircuitBuilder>;
+
 template <typename Builder>
 void build_constraints(Builder& builder, AcirFormat const& constraint_system, bool has_valid_witness_assignments)
 {
@@ -90,11 +94,15 @@ void build_constraints(Builder& builder, AcirFormat const& constraint_system, bo
     }
 
     // Add big_int constraints
+    DSLBigInts<Builder> dsl_bigints;
+    for (const auto& constraint : constraint_system.bigint_from_le_bytes_constraints) {
+        create_bigint_from_le_bytes_constraint(builder, constraint, dsl_bigints);
+    }
     for (const auto& constraint : constraint_system.bigint_operations) {
-        create_bigint_operations_constraint(builder, constraint);
+        create_bigint_operations_constraint<Builder>(constraint, dsl_bigints);
     }
-    for (const auto& constraint : constraint_system.bigint_from_le_bytes_constraints) {
-        create_bigint_from_le_bytes_constraint(builder, constraint);
+    for (const auto& constraint : constraint_system.bigint_to_le_bytes_constraints) {
+        create_bigint_to_le_bytes_constraint(builder, constraint, dsl_bigints);
     }
 
     // TODO(https://github.com/AztecProtocol/barretenberg/issues/817): disable these for UGH for now since we're not yet

diff --git a/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_format.hpp b/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_format.hpp
@@ -48,6 +48,7 @@ struct AcirFormat {
     std::vector<EcAdd> ec_add_constraints;
     std::vector<RecursionConstraint> recursion_constraints;
     std::vector<BigIntFromLeBytes> bigint_from_le_bytes_constraints;
+    std::vector<BigIntToLeBytes> bigint_to_le_bytes_constraints;
     std::vector<BigIntOperation> bigint_operations;
 
     // A standard plonk arithmetic constraint, as defined in the poly_triple struct, consists of selector values
@@ -80,6 +81,7 @@ struct AcirFormat {
                    constraints,
                    block_constraints,
                    bigint_from_le_bytes_constraints,
+                   bigint_to_le_bytes_constraints,
                    bigint_operations);
 
     friend bool operator==(AcirFormat const& lhs, AcirFormat const& rhs) = default;

diff --git a/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_format.test.cpp b/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_format.test.cpp
@@ -48,6 +48,7 @@ TEST_F(AcirFormatTests, TestASingleConstraintNoPubInputs)
         .ec_add_constraints = {},
         .recursion_constraints = {},
         .bigint_from_le_bytes_constraints = {},
+        .bigint_to_le_bytes_constraints = {},
         .bigint_operations = {},
         .constraints = { constraint },
         .block_constraints = {},
@@ -161,6 +162,7 @@ TEST_F(AcirFormatTests, TestLogicGateFromNoirCircuit)
                                   .ec_add_constraints = {},
                                   .recursion_constraints = {},
                                   .bigint_from_le_bytes_constraints = {},
+                                  .bigint_to_le_bytes_constraints = {},
                                   .bigint_operations = {},
                                   .constraints = { expr_a, expr_b, expr_c, expr_d },
                                   .block_constraints = {} };
@@ -226,6 +228,7 @@ TEST_F(AcirFormatTests, TestSchnorrVerifyPass)
                                   .ec_add_constraints = {},
                                   .recursion_constraints = {},
                                   .bigint_from_le_bytes_constraints = {},
+                                  .bigint_to_le_bytes_constraints = {},
                                   .bigint_operations = {},
                                   .constraints = { poly_triple{
                                       .a = schnorr_constraint.result,
@@ -319,6 +322,7 @@ TEST_F(AcirFormatTests, TestSchnorrVerifySmallRange)
         .ec_add_constraints = {},
         .recursion_constraints = {},
         .bigint_from_le_bytes_constraints = {},
+        .bigint_to_le_bytes_constraints = {},
         .bigint_operations = {},
         .constraints = { poly_triple{
             .a = schnorr_constraint.result,
@@ -431,6 +435,7 @@ TEST_F(AcirFormatTests, TestVarKeccak)
         .ec_add_constraints = {},
         .recursion_constraints = {},
         .bigint_from_le_bytes_constraints = {},
+        .bigint_to_le_bytes_constraints = {},
         .bigint_operations = {},
         .constraints = { dummy },
         .block_constraints = {},
@@ -475,6 +480,7 @@ TEST_F(AcirFormatTests, TestKeccakPermutation)
                                   .ec_add_constraints = {},
                                   .recursion_constraints = {},
                                   .bigint_from_le_bytes_constraints = {},
+                                  .bigint_to_le_bytes_constraints = {},
                                   .bigint_operations = {},
                                   .constraints = {},
                                   .block_constraints = {} };

diff --git a/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_to_constraint_buf.hpp b/barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_to_constraint_buf.hpp
@@ -256,6 +256,11 @@ void handle_blackbox_func_call(Circuit::Opcode::BlackBoxFuncCall const& arg, Aci
                     .modulus = map(arg.modulus, [](auto& e) -> uint32_t { return e; }),
                     .result = arg.output,
                 });
+            } else if constexpr (std::is_same_v<T, Circuit::BlackBoxFuncCall::BigIntToLeBytes>) {
+                af.bigint_to_le_bytes_constraints.push_back(BigIntToLeBytes{
+                    .input = arg.input,
+                    .result = map(arg.outputs, [](auto& e) { return e.value; }),
+                });
             } else if constexpr (std::is_same_v<T, Circuit::BlackBoxFuncCall::BigIntAdd>) {
                 af.bigint_operations.push_back(BigIntOperation{
                     .lhs = arg.lhs,
@@ -268,7 +273,7 @@ void handle_blackbox_func_call(Circuit::Opcode::BlackBoxFuncCall const& arg, Aci
                     .lhs = arg.lhs,
                     .rhs = arg.rhs,
                     .result = arg.output,
-                    .opcode = BigIntOperationType::Neg,
+                    .opcode = BigIntOperationType::Sub,
                 });
             } else if constexpr (std::is_same_v<T, Circuit::BlackBoxFuncCall::BigIntMul>) {
                 af.bigint_operations.push_back(BigIntOperation{