continuations: Remove the need for dummy segments

Cargo.toml

@@ -19,12 +19,13 @@ serde = "1.0.166"
 serde_json = "1.0.96"
 serde-big-array = "0.5.1"
 thiserror = "1.0.49"
+hashbrown = "0.14.0"
 
 # plonky2-related dependencies
-plonky2 = "0.2.2"
+plonky2 = { git = "https://github.com/0xPolygonZero/plonky2.git", rev = "dc77c77f2b06500e16ad4d7f1c2b057903602eed" }
 plonky2_maybe_rayon = "0.2.0"
-plonky2_util = "0.2.0"
-starky = "0.4.0"
+plonky2_util = { git = "https://github.com/0xPolygonZero/plonky2.git", rev = "dc77c77f2b06500e16ad4d7f1c2b057903602eed" }
+starky = { git = "https://github.com/0xPolygonZero/plonky2.git", rev = "dc77c77f2b06500e16ad4d7f1c2b057903602eed" }
 
 
 [workspace.package]

evm_arithmetization/Cargo.toml

@@ -36,7 +36,7 @@ rlp = { workspace = true }
 rlp-derive = { workspace = true }
 serde = { workspace = true, features = ["derive"] }
 static_assertions = "1.1.0"
-hashbrown = { version = "0.14.0" }
+hashbrown = { workspace = true }
 tiny-keccak = "2.0.2"
 serde_json = { workspace = true }
 serde-big-array = { workspace = true }

evm_arithmetization/src/cpu/kernel/interpreter.rs

@@ -422,7 +422,7 @@ impl<F: Field> Interpreter<F> {
     }
 
     pub(crate) fn run(&mut self) -> Result<(RegistersState, Option<MemoryState>), anyhow::Error> {
-        let (final_registers, final_mem) = self.run_cpu(self.max_cpu_len_log, self.is_dummy)?;
+        let (final_registers, final_mem) = self.run_cpu(self.max_cpu_len_log)?;
 
         #[cfg(debug_assertions)]
         {

evm_arithmetization/src/cpu/kernel/tests/bignum/mod.rs

@@ -9,7 +9,6 @@ use itertools::Itertools;
 use num::{BigUint, One, Zero};
 use num_bigint::RandBigInt;
 use plonky2::field::goldilocks_field::GoldilocksField as F;
-use plonky2_util::ceil_div_usize;
 use rand::Rng;
 
 use crate::cpu::kernel::aggregator::KERNEL;
@@ -90,7 +89,7 @@ fn max_bignum(bit_size: usize) -> BigUint {
 }
 
 fn bignum_len(a: &BigUint) -> usize {
-    ceil_div_usize(a.bits() as usize, BIGNUM_LIMB_BITS)
+    (a.bits() as usize).div_ceil(BIGNUM_LIMB_BITS)
 }
 
 fn run_test(fn_label: &str, memory: Vec<U256>, stack: Vec<U256>) -> Result<(Vec<U256>, Vec<U256>)> {

evm_arithmetization/src/cpu/kernel/tests/init_exc_stop.rs

@@ -13,8 +13,12 @@ use crate::generation::state::State;
 use crate::generation::TrieInputs;
 use crate::generation::NUM_EXTRA_CYCLES_AFTER;
 use crate::generation::NUM_EXTRA_CYCLES_BEFORE;
+use crate::memory::segments::Segment;
 use crate::proof::BlockMetadata;
+use crate::proof::RegistersData;
+use crate::proof::RegistersIdx;
 use crate::proof::TrieRoots;
+use crate::witness::memory::MemoryAddress;
 use crate::witness::state::RegistersState;
 use crate::{proof::BlockHashes, GenerationInputs, Node};
 
@@ -89,19 +93,49 @@ fn test_init_exc_stop() {
         "Incorrect registers for dummy run."
     );
 
-    let main_offset = KERNEL.global_labels["main"];
-    let mut interpreter: Interpreter<F> =
-        Interpreter::new_dummy_with_generation_inputs(initial_offset, vec![], &inputs);
+    let exc_stop_offset = KERNEL.global_labels["exc_stop"];
+
+    let pc_u256 = U256::from(interpreter.get_registers().program_counter);
+    let exit_info = pc_u256 + (U256::one() << 32);
+    interpreter.push(exit_info).unwrap();
+    interpreter.get_mut_registers().program_counter = exc_stop_offset;
     interpreter.halt_offsets = vec![KERNEL.global_labels["halt_final"]];
     interpreter.set_is_kernel(true);
     interpreter.clock = 0;
+
+    // Set the program counter and `is_kernel` at the end of the execution. The
+    // `registers_before` and `registers_after` are stored contiguously in the
+    // `RegistersState` segment. We need to update `registers_after` here, hence the
+    // offset by `RegistersData::SIZE`.
+    let regs_to_set = [
+        (
+            MemoryAddress {
+                context: 0,
+                segment: Segment::RegistersStates.unscale(),
+                virt: RegistersData::SIZE + RegistersIdx::ProgramCounter as usize,
+            },
+            pc_u256,
+        ),
+        (
+            MemoryAddress {
+                context: 0,
+                segment: Segment::RegistersStates.unscale(),
+                virt: RegistersData::SIZE + RegistersIdx::IsKernel as usize,
+            },
+            U256::one(),
+        ),
+    ];
+    interpreter.set_memory_multi_addresses(&regs_to_set);
+
     interpreter.run().expect("Running dummy exc_stop failed.");
 
-    // The "-1" comes from the fact that we stop 1 cycle before the max, to allow
-    // for one padding row, which is needed for CPU STARK.
+    // The "-2" comes from the fact that:
+    // - we stop 1 cycle before the max, to allow for one padding row, which is
+    //   needed for CPU STARK.
+    // - we need one additional cycle to enter `exc_stop`.
     assert_eq!(
         interpreter.get_clock(),
-        NUM_EXTRA_CYCLES_BEFORE + NUM_EXTRA_CYCLES_AFTER - 1,
+        NUM_EXTRA_CYCLES_AFTER - 2,
         "NUM_EXTRA_CYCLES_AFTER is set incorrectly."
     );
 }

evm_arithmetization/src/cpu/kernel/utils.rs

@@ -1,7 +1,6 @@
 use core::fmt::Debug;
 
 use ethereum_types::U256;
-use plonky2_util::ceil_div_usize;
 
 /// Enumerate the length `W` windows of `vec`, and run `maybe_replace` on each
 /// one.
@@ -28,7 +27,7 @@ where
 }
 
 pub(crate) fn u256_to_trimmed_be_bytes(u256: &U256) -> Vec<u8> {
-    let num_bytes = ceil_div_usize(u256.bits(), 8);
+    let num_bytes = u256.bits().div_ceil(8);
     // `byte` is little-endian, so we manually reverse it.
     (0..num_bytes).rev().map(|i| u256.byte(i)).collect()
 }