chore: reuse unmodified step memory

crates/evm/core/src/debug.rs

@@ -1,3 +1,4 @@
+use crate::opcodes;
 use alloy_primitives::{Address, Bytes, U256};
 use revm::interpreter::OpCode;
 use revm_inspectors::tracing::types::CallKind;
@@ -168,11 +169,11 @@ pub struct DebugStep {
  /// Stack *prior* to running the associated opcode
  pub stack: Vec<U256>,
  /// Memory *prior* to running the associated opcode
- pub memory: Vec<u8>,
+ pub memory: Bytes,
  /// Calldata *prior* to running the associated opcode
  pub calldata: Bytes,
  /// Returndata *prior* to running the associated opcode
- pub returndata: Vec<u8>,
+ pub returndata: Bytes,
  /// Opcode to be executed
  pub instruction: Instruction,
  /// Optional bytes that are being pushed onto the stack
@@ -210,6 +211,11 @@ impl DebugStep {
  self.instruction.to_string()
  }
  }
+
+ /// Returns `true` if the opcode modifies memory.
+ pub fn opcode_modifies_memory(&self) -> bool {
+ self.instruction.opcode().and_then(OpCode::new).map_or(false, opcodes::modifies_memory)
+ }
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize)]
@@ -249,3 +255,14 @@ impl Display for Instruction {
  }
  }
 }
+
+impl Instruction {
+ /// Returns the opcode of the instruction, if it is an opcode.
+ #[inline]
+ pub fn opcode(&self) -> Option<u8> {
+ match self {
+ Instruction::OpCode(op) => Some(*op),
+ _ => None,
+ }
+ }
+}

crates/evm/core/src/lib.rs

@@ -15,6 +15,7 @@ pub mod constants;
 pub mod debug;
 pub mod decode;
 pub mod fork;
+pub mod opcodes;
 pub mod opts;
 pub mod snapshot;
 pub mod utils;

crates/evm/core/src/opcodes.rs

@@ -0,0 +1,25 @@
+//! Opcode utils
+
+use revm::interpreter::OpCode;
+
+/// Returns true if the opcode modifies memory.
+/// <https://bluealloy.github.io/revm/crates/interpreter/memory.html#opcodes>
+/// <https://github.com/crytic/evm-opcodes>
+#[inline]
+pub const fn modifies_memory(opcode: OpCode) -> bool {
+ matches!(
+ opcode,
+ OpCode::EXTCODECOPY |
+ OpCode::MLOAD |
+ OpCode::MSTORE |
+ OpCode::MSTORE8 |
+ OpCode::MCOPY |
+ OpCode::CODECOPY |
+ OpCode::CALLDATACOPY |
+ OpCode::RETURNDATACOPY |
+ OpCode::CALL |
+ OpCode::CALLCODE |
+ OpCode::DELEGATECALL |
+ OpCode::STATICCALL
+ )
+}

crates/evm/evm/src/inspectors/debugger.rs

@@ -72,12 +72,28 @@ impl<DB: DatabaseExt> Inspector<DB> for Debugger {
  interp.gas.refunded() as u64,
  );
 
+ // if the previous opcode does __not__ modify memory, we can reuse the memory of
+ // that step
+ let memory = self.arena.arena[self.head]
+ .steps
+ .last()
+ .and_then(|step| {
+ if !step.opcode_modifies_memory() {
+ // reuse the memory from the previous step, because its opcode did not modify
+ // memory
+ Some(step.memory.clone())
+ } else {
+ None
+ }
+ })
+ .unwrap_or_else(|| interp.shared_memory.context_memory().to_vec().into());
+
  self.arena.arena[self.head].steps.push(DebugStep {
  pc,
  stack: interp.stack().data().clone(),
- memory: interp.shared_memory.context_memory().to_vec(),
+ memory,
  calldata: interp.contract().input.clone(),
- returndata: interp.return_data_buffer.to_vec(),
+ returndata: interp.return_data_buffer.clone(),
  instruction: Instruction::OpCode(op),
  push_bytes,
  total_gas_used,