From 3a90eac8b101ff5a5f459595d7a716ba6522d695 Mon Sep 17 00:00:00 2001
From: Matthias Seitz <matthias.seitz@outlook.de>
Date: Thu, 15 Jun 2023 13:13:51 +0200
Subject: [PATCH] fix: exclude calls to precompiles in call graphs (#3141)

---
 .../revm/revm-inspectors/src/tracing/arena.rs | 38 ++++++++++++++++---
 .../revm/revm-inspectors/src/tracing/mod.rs   | 15 +++++++-
 2 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/crates/revm/revm-inspectors/src/tracing/arena.rs b/crates/revm/revm-inspectors/src/tracing/arena.rs
index 9e8ffa02ef..fc7d12896f 100644
--- a/crates/revm/revm-inspectors/src/tracing/arena.rs
+++ b/crates/revm/revm-inspectors/src/tracing/arena.rs
@@ -11,7 +11,16 @@ pub struct CallTraceArena {
 
 impl CallTraceArena {
     /// Pushes a new trace into the arena, returning the trace ID
-    pub(crate) fn push_trace(&mut self, mut entry: usize, new_trace: CallTrace) -> usize {
+    ///
+    /// This appends a new trace to the arena, and also inserts a new entry in the node's parent
+    /// node children set if `attach_to_parent` is `true`. E.g. if calls to precompiles should
+    /// not be included in the call graph this should be called with [PushTraceKind::PushOnly].
+    pub(crate) fn push_trace(
+        &mut self,
+        mut entry: usize,
+        kind: PushTraceKind,
+        new_trace: CallTrace,
+    ) -> usize {
         loop {
             match new_trace.depth {
                 // The entry node, just update it
@@ -22,9 +31,6 @@ impl CallTraceArena {
                 // We found the parent node, add the new trace as a child
                 _ if self.arena[entry].trace.depth == new_trace.depth - 1 => {
                     let id = self.arena.len();
-
-                    let trace_location = self.arena[entry].children.len();
-                    self.arena[entry].ordering.push(LogCallOrder::Call(trace_location));
                     let node = CallTraceNode {
                         parent: Some(entry),
                         trace: new_trace,
@@ -32,7 +38,14 @@ impl CallTraceArena {
                         ..Default::default()
                     };
                     self.arena.push(node);
-                    self.arena[entry].children.push(id);
+
+                    // also track the child in the parent node
+                    if kind.is_attach_to_parent() {
+                        let parent = &mut self.arena[entry];
+                        let trace_location = parent.children.len();
+                        parent.ordering.push(LogCallOrder::Call(trace_location));
+                        parent.children.push(id);
+                    }
 
                     return id
                 }
@@ -45,6 +58,21 @@ impl CallTraceArena {
     }
 }
 
+/// How to push a trace into the arena
+pub(crate) enum PushTraceKind {
+    /// This will _only_ push the trace into the arena.
+    PushOnly,
+    /// This will push the trace into the arena, and also insert a new entry in the node's parent
+    /// node children set.
+    PushAndAttachToParent,
+}
+
+impl PushTraceKind {
+    fn is_attach_to_parent(&self) -> bool {
+        matches!(self, PushTraceKind::PushAndAttachToParent)
+    }
+}
+
 impl Default for CallTraceArena {
     fn default() -> Self {
         // The first node is the root node
diff --git a/crates/revm/revm-inspectors/src/tracing/mod.rs b/crates/revm/revm-inspectors/src/tracing/mod.rs
index 26504a71d6..0ea99f90dd 100644
--- a/crates/revm/revm-inspectors/src/tracing/mod.rs
+++ b/crates/revm/revm-inspectors/src/tracing/mod.rs
@@ -21,7 +21,10 @@ mod fourbyte;
 mod opcount;
 mod types;
 mod utils;
-use crate::tracing::types::{CallTraceNode, StorageChange};
+use crate::tracing::{
+    arena::PushTraceKind,
+    types::{CallTraceNode, StorageChange},
+};
 pub use builder::{geth::GethTraceBuilder, parity::ParityTraceBuilder};
 pub use config::TracingInspectorConfig;
 pub use fourbyte::FourByteInspector;
@@ -126,8 +129,18 @@ impl TracingInspector {
         caller: Address,
         maybe_precompile: Option<bool>,
     ) {
+        // This will only be true if the inspector is configured to exclude precompiles and the call
+        // is to a precompile
+        let push_kind = if maybe_precompile.unwrap_or(false) {
+            // We don't want to track precompiles
+            PushTraceKind::PushOnly
+        } else {
+            PushTraceKind::PushAndAttachToParent
+        };
+
         self.trace_stack.push(self.traces.push_trace(
             0,
+            push_kind,
             CallTrace {
                 depth,
                 address,