feat: TracerEip3155 optionally traces memory (bluealloy#1234)

* feat: TracerEip3155 optionally traces memory

BREAKING CHANGE: the TracerEIP3155 constructor takes an additional
"include_memory" flag

* perf: use hex::encode_prefixed for TracerEip3155

* refactor: use builder pattern for TracerEip3155

BREAKING CHANGE: update constructor syntax for TracerEip3155

* refactor: use String for TracerEip3155 memory

bins/revme/src/cmd/statetest/runner.rs

@@ -355,10 +355,7 @@ pub fn execute_test_suite(
                 let (e, exec_result) = if trace {
                     let mut evm = evm
                         .modify()
-                        .reset_handler_with_external_context(TracerEip3155::new(
-                            Box::new(stderr()),
-                            false,
-                        ))
+                        .reset_handler_with_external_context(TracerEip3155::new(Box::new(stderr())))
                         .append_handler_register(inspector_handle_register)
                         .build();
 
@@ -421,7 +418,7 @@ pub fn execute_test_suite(
                 let mut evm = Evm::builder()
                     .with_spec_id(spec_id)
                     .with_db(state)
-                    .with_external_context(TracerEip3155::new(Box::new(stdout()), false))
+                    .with_external_context(TracerEip3155::new(Box::new(stdout())))
                     .append_handler_register(inspector_handle_register)
                     .build();
                 let _ = evm.transact_commit();

crates/revm/src/inspector/eip3155.rs

@@ -22,6 +22,8 @@ pub struct TracerEip3155 {
     refunded: i64,
     mem_size: usize,
     skip: bool,
+    include_memory: bool,
+    memory: Option<String>,
 }
 
 // # Output
@@ -58,7 +60,7 @@ struct Output {
     error: Option<String>,
     /// Array of all allocated values
     #[serde(default, skip_serializing_if = "Option::is_none")]
-    memory: Option<Vec<String>>,
+    memory: Option<String>,
     /// Array of all stored values
     #[serde(default, skip_serializing_if = "Option::is_none")]
     storage: Option<HashMap<String, String>>,
@@ -98,12 +100,14 @@ impl TracerEip3155 {
 }
 
 impl TracerEip3155 {
-    pub fn new(output: Box<dyn Write>, print_summary: bool) -> Self {
+    pub fn new(output: Box<dyn Write>) -> Self {
         Self {
             output,
             gas_inspector: GasInspector::default(),
-            print_summary,
+            print_summary: true,
+            include_memory: false,
             stack: Default::default(),
+            memory: Default::default(),
             pc: 0,
             opcode: 0,
             gas: 0,
@@ -113,6 +117,18 @@ impl TracerEip3155 {
         }
     }
 
+    /// Don't include a summary at the end of the trace
+    pub fn without_summary(mut self) -> Self {
+        self.print_summary = false;
+        self
+    }
+
+    /// Include a memory field for each step. This significantly increases processing time and output size.
+    pub fn with_memory(mut self) -> Self {
+        self.include_memory = true;
+        self
+    }
+
     fn write_value(&mut self, value: &impl serde::Serialize) -> std::io::Result<()> {
         serde_json::to_writer(&mut *self.output, value)?;
         self.output.write_all(b"\n")?;
@@ -128,6 +144,11 @@ impl<DB: Database> Inspector<DB> for TracerEip3155 {
     fn step(&mut self, interp: &mut Interpreter, context: &mut EvmContext<DB>) {
         self.gas_inspector.step(interp, context);
         self.stack = interp.stack.data().clone();
+        self.memory = if self.include_memory {
+            Some(hex::encode_prefixed(interp.shared_memory.context_memory()))
+        } else {
+            None
+        };
         self.pc = interp.program_counter();
         self.opcode = interp.current_opcode();
         self.mem_size = interp.shared_memory.len();
@@ -159,7 +180,7 @@ impl<DB: Database> Inspector<DB> for TracerEip3155 {
             } else {
                 None
             },
-            memory: None,
+            memory: self.memory.take(),
             storage: None,
             return_stack: None,
         };

examples/db_by_ref.rs

@@ -72,7 +72,7 @@ fn run_transaction_and_commit(db: &mut CacheDB<EmptyDB>) -> anyhow::Result<()> {
 fn main() -> anyhow::Result<()> {
     let mut cache_db = CacheDB::new(EmptyDB::default());
 
-    let mut tracer = TracerEip3155::new(Box::new(std::io::stdout()), true);
+    let mut tracer = TracerEip3155::new(Box::new(std::io::stdout()));
 
     run_transaction_and_commit_with_ext(&mut cache_db, &mut tracer, inspector_handle_register)?;
     run_transaction_and_commit(&mut cache_db)?;

examples/generate_block_traces.rs

@@ -76,7 +76,7 @@ async fn main() -> anyhow::Result<()> {
     let mut state = StateBuilder::new_with_database(cache_db).build();
     let mut evm = Evm::builder()
         .with_db(&mut state)
-        .with_external_context(TracerEip3155::new(Box::new(std::io::stdout()), true))
+        .with_external_context(TracerEip3155::new(Box::new(std::io::stdout())))
         .modify_block_env(|b| {
             if let Some(number) = block.number {
                 let nn = number.0[0];