From e8f5f529e12fda76df170029320ed86fee2e9438 Mon Sep 17 00:00:00 2001
From: Eduard S <eduardsanou@posteo.net>
Date: Wed, 22 Feb 2023 16:58:03 +0100
Subject: [PATCH 1/3] feat: cache EVM circuit configuration in unit tests

---
 zkevm-circuits/src/evm_circuit.rs | 60 +++++++++++++++++++++++++++++++
 zkevm-circuits/src/test_util.rs   |  4 +--
 2 files changed, 62 insertions(+), 2 deletions(-)

diff --git a/zkevm-circuits/src/evm_circuit.rs b/zkevm-circuits/src/evm_circuit.rs
index 642a883328..1775ca0a8e 100644
--- a/zkevm-circuits/src/evm_circuit.rs
+++ b/zkevm-circuits/src/evm_circuit.rs
@@ -285,6 +285,66 @@ pub(crate) fn detect_fixed_table_tags<F: Field>(block: &Block<F>) -> Vec<FixedTa
         .collect()
 }
 
+#[cfg(any(feature = "test", test))]
+pub(crate) mod cached {
+    use super::*;
+    use halo2_proofs::halo2curves::bn256::Fr;
+    use lazy_static::lazy_static;
+    use std::sync::Mutex;
+
+    struct Cache {
+        cs: ConstraintSystem<Fr>,
+        config: (EvmCircuitConfig<Fr>, Challenges),
+    }
+
+    lazy_static! {
+        static ref CACHE: Mutex<Option<Cache>> = Mutex::new(None);
+    }
+
+    pub struct EvmCircuitCached(EvmCircuit<Fr>);
+
+    impl Circuit<Fr> for EvmCircuitCached {
+        type Config = (EvmCircuitConfig<Fr>, Challenges);
+        type FloorPlanner = SimpleFloorPlanner;
+
+        fn without_witnesses(&self) -> Self {
+            Self(self.0.without_witnesses())
+        }
+
+        fn configure(meta: &mut ConstraintSystem<Fr>) -> Self::Config {
+            let mut cache = CACHE.lock().unwrap();
+            match &*cache {
+                Some(Cache { cs, config }) => {
+                    *meta = cs.clone();
+                    config.clone()
+                }
+                None => {
+                    let config = EvmCircuit::<Fr>::configure(meta);
+                    *cache = Some(Cache {
+                        cs: meta.clone(),
+                        config: config.clone(),
+                    });
+                    config
+                }
+            }
+        }
+
+        fn synthesize(
+            &self,
+            config: Self::Config,
+            layouter: impl Layouter<Fr>,
+        ) -> Result<(), Error> {
+            self.0.synthesize(config, layouter)
+        }
+    }
+
+    impl EvmCircuitCached {
+        pub fn get_test_cicuit_from_block(block: Block<Fr>) -> Self {
+            Self(EvmCircuit::<Fr>::get_test_cicuit_from_block(block))
+        }
+    }
+}
+
 // Always exported because of `EXECUTION_STATE_HEIGHT_MAP`
 impl<F: Field> Circuit<F> for EvmCircuit<F> {
     type Config = (EvmCircuitConfig<F>, Challenges);
diff --git a/zkevm-circuits/src/test_util.rs b/zkevm-circuits/src/test_util.rs
index ee01046c3b..e994f8a3b1 100644
--- a/zkevm-circuits/src/test_util.rs
+++ b/zkevm-circuits/src/test_util.rs
@@ -1,7 +1,7 @@
 //! Testing utilities
 
 use crate::{
-    evm_circuit::EvmCircuit,
+    evm_circuit::{cached::EvmCircuitCached, EvmCircuit},
     state_circuit::StateCircuit,
     util::SubCircuit,
     witness::{Block, Rw},
@@ -211,7 +211,7 @@ impl<const NACC: usize, const NTX: usize> CircuitTestBuilder<NACC, NTX> {
 
             let (active_gate_rows, active_lookup_rows) = EvmCircuit::<Fr>::get_active_rows(&block);
 
-            let circuit = EvmCircuit::<Fr>::get_test_cicuit_from_block(block.clone());
+            let circuit = EvmCircuitCached::get_test_cicuit_from_block(block.clone());
             let prover = MockProver::<Fr>::run(k, &circuit, vec![]).unwrap();
 
             self.evm_checks.as_ref()(prover, &active_gate_rows, &active_lookup_rows)

From 853cc9ccc37585db3ec4a2ac362a225bac329a1b Mon Sep 17 00:00:00 2001
From: Eduard S <eduardsanou@posteo.net>
Date: Wed, 22 Feb 2023 17:23:07 +0100
Subject: [PATCH 2/3] Remove mutex

---
 zkevm-circuits/src/evm_circuit.rs | 27 ++++++++++-----------------
 1 file changed, 10 insertions(+), 17 deletions(-)

diff --git a/zkevm-circuits/src/evm_circuit.rs b/zkevm-circuits/src/evm_circuit.rs
index 1775ca0a8e..c6feb4abd7 100644
--- a/zkevm-circuits/src/evm_circuit.rs
+++ b/zkevm-circuits/src/evm_circuit.rs
@@ -290,7 +290,6 @@ pub(crate) mod cached {
     use super::*;
     use halo2_proofs::halo2curves::bn256::Fr;
     use lazy_static::lazy_static;
-    use std::sync::Mutex;
 
     struct Cache {
         cs: ConstraintSystem<Fr>,
@@ -298,7 +297,14 @@ pub(crate) mod cached {
     }
 
     lazy_static! {
-        static ref CACHE: Mutex<Option<Cache>> = Mutex::new(None);
+        static ref CACHE: Cache = {
+            let mut meta = ConstraintSystem::<Fr>::default();
+            let config = EvmCircuit::<Fr>::configure(&mut meta);
+            Cache {
+                cs: meta,
+                config: config,
+            }
+        };
     }
 
     pub struct EvmCircuitCached(EvmCircuit<Fr>);
@@ -312,21 +318,8 @@ pub(crate) mod cached {
         }
 
         fn configure(meta: &mut ConstraintSystem<Fr>) -> Self::Config {
-            let mut cache = CACHE.lock().unwrap();
-            match &*cache {
-                Some(Cache { cs, config }) => {
-                    *meta = cs.clone();
-                    config.clone()
-                }
-                None => {
-                    let config = EvmCircuit::<Fr>::configure(meta);
-                    *cache = Some(Cache {
-                        cs: meta.clone(),
-                        config: config.clone(),
-                    });
-                    config
-                }
-            }
+            *meta = CACHE.cs.clone();
+            CACHE.config.clone()
         }
 
         fn synthesize(

From 990d252c493f19f9e5680d4535942c0a57db986b Mon Sep 17 00:00:00 2001
From: Eduard S <eduardsanou@posteo.net>
Date: Wed, 22 Feb 2023 17:42:33 +0100
Subject: [PATCH 3/3] Enable incremental compilation

---
 Cargo.toml                        | 2 +-
 zkevm-circuits/src/evm_circuit.rs | 6 ++----
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index ae60130c36..100836d5ce 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -34,4 +34,4 @@ debug-assertions = true
 overflow-checks = true
 rpath = false
 lto = "thin"
-incremental = false
+incremental = true
diff --git a/zkevm-circuits/src/evm_circuit.rs b/zkevm-circuits/src/evm_circuit.rs
index c6feb4abd7..0c19a6f59d 100644
--- a/zkevm-circuits/src/evm_circuit.rs
+++ b/zkevm-circuits/src/evm_circuit.rs
@@ -291,6 +291,7 @@ pub(crate) mod cached {
     use halo2_proofs::halo2curves::bn256::Fr;
     use lazy_static::lazy_static;
 
+    /// Cache
     struct Cache {
         cs: ConstraintSystem<Fr>,
         config: (EvmCircuitConfig<Fr>, Challenges),
@@ -300,10 +301,7 @@ pub(crate) mod cached {
         static ref CACHE: Cache = {
             let mut meta = ConstraintSystem::<Fr>::default();
             let config = EvmCircuit::<Fr>::configure(&mut meta);
-            Cache {
-                cs: meta,
-                config: config,
-            }
+            Cache { cs: meta, config }
         };
     }