From ad79c3059ddba0633c1159b3db5f3aefe217ad79 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Tue, 11 May 2021 13:00:52 +0000
Subject: [PATCH 01/15] gasometer tracing

---
 gasometer/Cargo.toml     |  5 +++++
 gasometer/src/lib.rs     | 17 ++++++++++++--
 gasometer/src/tracing.rs | 48 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+), 2 deletions(-)
 create mode 100644 gasometer/src/tracing.rs

diff --git a/gasometer/Cargo.toml b/gasometer/Cargo.toml
index 1cb0e0b11..c3b7c1604 100644
--- a/gasometer/Cargo.toml
+++ b/gasometer/Cargo.toml
@@ -12,6 +12,7 @@ edition = "2018"
 primitive-types = { version = "0.9", default-features = false }
 evm-core = { version = "0.26", path = "../core", default-features = false }
 evm-runtime = { version = "0.26", path = "../runtime", default-features = false }
+environmental = { version = "1.1.2", default-features = false, optional = true}
 
 [features]
 default = ["std"]
@@ -19,4 +20,8 @@ std = [
   "evm-core/std",
   "evm-runtime/std",
   "primitive-types/std",
+  "environmental/std"
 ]
+tracing = [
+  "environmental"
+]
\ No newline at end of file
diff --git a/gasometer/src/lib.rs b/gasometer/src/lib.rs
index 0d09828ae..8a63b2bd8 100644
--- a/gasometer/src/lib.rs
+++ b/gasometer/src/lib.rs
@@ -1,7 +1,7 @@
 //! EVM gasometer.
 
 #![deny(warnings)]
-#![forbid(unsafe_code, unused_variables, unused_imports)]
+#![forbid(unsafe_code, unused_variables)]
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
@@ -9,6 +9,7 @@ mod consts;
 mod costs;
 mod memory;
 mod utils;
+pub mod tracing;
 
 use core::cmp::max;
 use primitive_types::{H160, H256, U256};
@@ -115,6 +116,8 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		cost: u64,
 	) -> Result<(), ExitError> {
+		tracing::emit(|| tracing::Event::RecordCost(cost));
+
 		let all_gas_cost = self.total_used_gas() + cost;
 		if self.gas_limit < all_gas_cost {
 			self.inner = Err(ExitError::OutOfGas);
@@ -131,6 +134,8 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		refund: i64,
 	) -> Result<(), ExitError> {
+		tracing::emit(|| tracing::Event::RecordRefund(refund));
+
 		self.inner_mut()?.refunded_gas += refund;
 		Ok(())
 	}
@@ -161,6 +166,10 @@ impl<'config> Gasometer<'config> {
 		let gas_refund = self.inner_mut()?.gas_refund(cost);
 		let used_gas = self.inner_mut()?.used_gas;
 
+		tracing::emit(|| tracing::Event::RecordDynamicCost {
+			gas_cost, memory_gas, gas_refund
+		});
+
 		let all_gas_cost = memory_gas + used_gas + gas_cost;
 		if self.gas_limit < all_gas_cost {
 			self.inner = Err(ExitError::OutOfGas);
@@ -183,6 +192,8 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		stipend: u64,
 	) -> Result<(), ExitError> {
+		tracing::emit(|| tracing::Event::RecordStipend(stipend));
+
 		self.inner_mut()?.used_gas -= stipend;
 		Ok(())
 	}
@@ -205,10 +216,12 @@ impl<'config> Gasometer<'config> {
 			},
 		};
 
+		tracing::emit(|| tracing::Event::RecordTransaction(gas_cost));
+
 		if self.gas() < gas_cost {
 			self.inner = Err(ExitError::OutOfGas);
 			return Err(ExitError::OutOfGas);
-		}
+		}		
 
 		self.inner_mut()?.used_gas += gas_cost;
 		Ok(())
diff --git a/gasometer/src/tracing.rs b/gasometer/src/tracing.rs
new file mode 100644
index 000000000..a11aece4c
--- /dev/null
+++ b/gasometer/src/tracing.rs
@@ -0,0 +1,48 @@
+//! Allow to listen to gasometer events. 
+//! Enable `tracing` feature for events to be emitted.
+
+#[cfg(feature = "tracing")]
+environmental::environmental!(hook: dyn EventListener + 'static);
+
+pub trait EventListener {
+    fn accept(&mut self, event: Event);
+}
+
+pub enum Event {
+    RecordCost(u64),
+    RecordRefund(i64),
+    RecordStipend(u64),
+    RecordDynamicCost {
+        gas_cost: u64,
+        memory_gas: u64,
+        gas_refund: i64,
+    },
+    RecordTransaction(u64),
+}
+
+#[cfg(feature = "tracing")]
+pub(crate) fn emit<F>(f: F)
+where
+    F: FnOnce() -> Event
+{
+    hook::with(|hook| {
+        hook.accept(f());
+    });
+}
+
+#[cfg(not(feature = "tracing"))]
+pub(crate) fn emit<F>(_f: F)
+where
+    F: FnOnce() -> Event
+{
+    // No-op.
+}
+
+/// Run closure with provided listener.
+#[cfg(feature = "tracing")]
+pub fn using<R, F: FnOnce() -> R>(
+    listener: &mut (dyn EventListener + 'static),
+    f: F
+) -> R {
+    hook::using(listener, f)
+}
\ No newline at end of file

From 94eb563b901eb3b17866b5ae3cdeef4381239000 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Tue, 11 May 2021 13:53:10 +0000
Subject: [PATCH 02/15] use trait methods and macro

---
 gasometer/src/lib.rs     | 14 +++++------
 gasometer/src/tracing.rs | 52 ++++++++++++++++------------------------
 2 files changed, 28 insertions(+), 38 deletions(-)

diff --git a/gasometer/src/lib.rs b/gasometer/src/lib.rs
index 8a63b2bd8..30e826bbd 100644
--- a/gasometer/src/lib.rs
+++ b/gasometer/src/lib.rs
@@ -9,6 +9,8 @@ mod consts;
 mod costs;
 mod memory;
 mod utils;
+
+#[macro_use]
 pub mod tracing;
 
 use core::cmp::max;
@@ -116,7 +118,7 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		cost: u64,
 	) -> Result<(), ExitError> {
-		tracing::emit(|| tracing::Event::RecordCost(cost));
+		event!(record_cost(cost));
 
 		let all_gas_cost = self.total_used_gas() + cost;
 		if self.gas_limit < all_gas_cost {
@@ -134,7 +136,7 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		refund: i64,
 	) -> Result<(), ExitError> {
-		tracing::emit(|| tracing::Event::RecordRefund(refund));
+		event!(record_refund(refund));
 
 		self.inner_mut()?.refunded_gas += refund;
 		Ok(())
@@ -166,9 +168,7 @@ impl<'config> Gasometer<'config> {
 		let gas_refund = self.inner_mut()?.gas_refund(cost);
 		let used_gas = self.inner_mut()?.used_gas;
 
-		tracing::emit(|| tracing::Event::RecordDynamicCost {
-			gas_cost, memory_gas, gas_refund
-		});
+		event!(record_dynamic_cost(gas_cost, memory_gas, gas_refund));
 
 		let all_gas_cost = memory_gas + used_gas + gas_cost;
 		if self.gas_limit < all_gas_cost {
@@ -192,7 +192,7 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		stipend: u64,
 	) -> Result<(), ExitError> {
-		tracing::emit(|| tracing::Event::RecordStipend(stipend));
+		event!(record_stipend(stipend));
 
 		self.inner_mut()?.used_gas -= stipend;
 		Ok(())
@@ -216,7 +216,7 @@ impl<'config> Gasometer<'config> {
 			},
 		};
 
-		tracing::emit(|| tracing::Event::RecordTransaction(gas_cost));
+		event!(record_transaction(gas_cost));
 
 		if self.gas() < gas_cost {
 			self.inner = Err(ExitError::OutOfGas);
diff --git a/gasometer/src/tracing.rs b/gasometer/src/tracing.rs
index a11aece4c..684e696a0 100644
--- a/gasometer/src/tracing.rs
+++ b/gasometer/src/tracing.rs
@@ -1,41 +1,19 @@
-//! Allow to listen to gasometer events. 
-//! Enable `tracing` feature for events to be emitted.
+//! Allows to listen to gasometer events.
 
 #[cfg(feature = "tracing")]
 environmental::environmental!(hook: dyn EventListener + 'static);
 
+#[cfg(feature = "tracing")]
 pub trait EventListener {
-    fn accept(&mut self, event: Event);
-}
-
-pub enum Event {
-    RecordCost(u64),
-    RecordRefund(i64),
-    RecordStipend(u64),
-    RecordDynamicCost {
+    fn record_cost(cost: u64) { }
+    fn record_refund(refund: i64) { }
+    fn record_stipend(stipend: u64) { }
+    fn record_dynamic_cost(
         gas_cost: u64,
         memory_gas: u64,
-        gas_refund: i64,
-    },
-    RecordTransaction(u64),
-}
-
-#[cfg(feature = "tracing")]
-pub(crate) fn emit<F>(f: F)
-where
-    F: FnOnce() -> Event
-{
-    hook::with(|hook| {
-        hook.accept(f());
-    });
-}
-
-#[cfg(not(feature = "tracing"))]
-pub(crate) fn emit<F>(_f: F)
-where
-    F: FnOnce() -> Event
-{
-    // No-op.
+        gas_refund: i64
+    ) { }
+    fn record_transaction(transaction_cost: u64) { }
 }
 
 /// Run closure with provided listener.
@@ -45,4 +23,16 @@ pub fn using<R, F: FnOnce() -> R>(
     f: F
 ) -> R {
     hook::using(listener, f)
+}
+
+#[cfg(not(feature = "tracing"))]
+macro_rules! event {
+    ($func_name: ident ( $($arg:expr),* )) => { }
+}
+
+#[cfg(feature = "tracing")]
+macro_rules! event {
+    ($method: ident ( $($arg:expr),* )) => {
+        hook::with(|hook| hook.$method( $($arg)* ));
+    }
 }
\ No newline at end of file

From cc5448498a27c9c7046a9ea118a6490736a890d2 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Tue, 11 May 2021 14:20:50 +0000
Subject: [PATCH 03/15] fix macro

---
 gasometer/src/tracing.rs | 66 ++++++++++++++++++++++++++++------------
 1 file changed, 46 insertions(+), 20 deletions(-)

diff --git a/gasometer/src/tracing.rs b/gasometer/src/tracing.rs
index 684e696a0..0a911c87f 100644
--- a/gasometer/src/tracing.rs
+++ b/gasometer/src/tracing.rs
@@ -1,29 +1,55 @@
 //! Allows to listen to gasometer events.
 
 #[cfg(feature = "tracing")]
-environmental::environmental!(hook: dyn EventListener + 'static);
+pub(crate) mod inner {
+    environmental::environmental!(hook: dyn EventListener + 'static);
 
-#[cfg(feature = "tracing")]
-pub trait EventListener {
-    fn record_cost(cost: u64) { }
-    fn record_refund(refund: i64) { }
-    fn record_stipend(stipend: u64) { }
-    fn record_dynamic_cost(
-        gas_cost: u64,
-        memory_gas: u64,
-        gas_refund: i64
-    ) { }
-    fn record_transaction(transaction_cost: u64) { }
+    pub trait EventListener {
+        fn record_cost(
+            &mut self,
+            _cost: u64
+        ) { }
+
+        fn record_refund(
+            &mut self,
+            _refund: i64
+        ) { }
+
+        fn record_stipend(
+            &mut self,
+            _stipend: u64
+        ) { }
+
+        fn record_dynamic_cost(
+            &mut self, 
+            _gas_cost: u64,
+            _memory_gas: u64,
+            _gas_refund: i64
+        ) { }
+
+        fn record_transaction(
+            &mut self,
+            _transaction_cost: u64
+        ) { }
+    }
+
+    /// Run closure with provided listener.
+    pub fn using<R, F: FnOnce() -> R>(
+        listener: &mut (dyn EventListener + 'static),
+        f: F
+    ) -> R {
+        hook::using(listener, f)
+    }
+
+    pub(crate) fn with<F: FnOnce(&mut (dyn EventListener + 'static))>(
+        f: F
+    ) {
+        hook::with(f);
+    }
 }
 
-/// Run closure with provided listener.
 #[cfg(feature = "tracing")]
-pub fn using<R, F: FnOnce() -> R>(
-    listener: &mut (dyn EventListener + 'static),
-    f: F
-) -> R {
-    hook::using(listener, f)
-}
+pub use inner::using;
 
 #[cfg(not(feature = "tracing"))]
 macro_rules! event {
@@ -33,6 +59,6 @@ macro_rules! event {
 #[cfg(feature = "tracing")]
 macro_rules! event {
     ($method: ident ( $($arg:expr),* )) => {
-        hook::with(|hook| hook.$method( $($arg)* ));
+        $crate::tracing::inner::with(|hook| hook.$method( $($arg),* ));
     }
 }
\ No newline at end of file

From baebf7011e103767d6304bfaacf1488a043df13b Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Wed, 12 May 2021 11:04:20 +0000
Subject: [PATCH 04/15] change back to enums

---
 gasometer/src/lib.rs       | 12 +++---
 gasometer/src/tracing.rs   | 84 +++++++++++++++-----------------------
 runtime/Cargo.toml         |  6 ++-
 runtime/src/eval/system.rs | 18 +++++++-
 runtime/src/lib.rs         | 11 ++++-
 runtime/src/tracing.rs     | 58 ++++++++++++++++++++++++++
 6 files changed, 127 insertions(+), 62 deletions(-)
 create mode 100644 runtime/src/tracing.rs

diff --git a/gasometer/src/lib.rs b/gasometer/src/lib.rs
index 30e826bbd..634e5114b 100644
--- a/gasometer/src/lib.rs
+++ b/gasometer/src/lib.rs
@@ -9,8 +9,6 @@ mod consts;
 mod costs;
 mod memory;
 mod utils;
-
-#[macro_use]
 pub mod tracing;
 
 use core::cmp::max;
@@ -118,7 +116,7 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		cost: u64,
 	) -> Result<(), ExitError> {
-		event!(record_cost(cost));
+		tracing::Event::RecordCost(cost).emit();
 
 		let all_gas_cost = self.total_used_gas() + cost;
 		if self.gas_limit < all_gas_cost {
@@ -136,7 +134,7 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		refund: i64,
 	) -> Result<(), ExitError> {
-		event!(record_refund(refund));
+		tracing::Event::RecordRefund(refund).emit();
 
 		self.inner_mut()?.refunded_gas += refund;
 		Ok(())
@@ -168,7 +166,7 @@ impl<'config> Gasometer<'config> {
 		let gas_refund = self.inner_mut()?.gas_refund(cost);
 		let used_gas = self.inner_mut()?.used_gas;
 
-		event!(record_dynamic_cost(gas_cost, memory_gas, gas_refund));
+		tracing::Event::RecordDynamicCost {gas_cost, memory_gas, gas_refund}.emit();
 
 		let all_gas_cost = memory_gas + used_gas + gas_cost;
 		if self.gas_limit < all_gas_cost {
@@ -192,7 +190,7 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		stipend: u64,
 	) -> Result<(), ExitError> {
-		event!(record_stipend(stipend));
+		tracing::Event::RecordStipend(stipend).emit();
 
 		self.inner_mut()?.used_gas -= stipend;
 		Ok(())
@@ -216,7 +214,7 @@ impl<'config> Gasometer<'config> {
 			},
 		};
 
-		event!(record_transaction(gas_cost));
+		tracing::Event::RecordTransaction(gas_cost).emit();
 
 		if self.gas() < gas_cost {
 			self.inner = Err(ExitError::OutOfGas);
diff --git a/gasometer/src/tracing.rs b/gasometer/src/tracing.rs
index 0a911c87f..2eba324b1 100644
--- a/gasometer/src/tracing.rs
+++ b/gasometer/src/tracing.rs
@@ -1,64 +1,46 @@
 //! Allows to listen to gasometer events.
 
 #[cfg(feature = "tracing")]
-pub(crate) mod inner {
-    environmental::environmental!(hook: dyn EventListener + 'static);
+environmental::environmental!(hook: dyn EventListener + 'static);
 
-    pub trait EventListener {
-        fn record_cost(
-            &mut self,
-            _cost: u64
-        ) { }
-
-        fn record_refund(
-            &mut self,
-            _refund: i64
-        ) { }
-
-        fn record_stipend(
-            &mut self,
-            _stipend: u64
-        ) { }
-
-        fn record_dynamic_cost(
-            &mut self, 
-            _gas_cost: u64,
-            _memory_gas: u64,
-            _gas_refund: i64
-        ) { }
+#[cfg(feature = "tracing")]
+pub trait EventListener {
+    fn event(
+        &mut self,
+        event: Event
+    );
+}
 
-        fn record_transaction(
-            &mut self,
-            _transaction_cost: u64
-        ) { }
-    }
+#[derive(Debug, Copy, Clone)]
+pub enum Event {
+    RecordCost(u64),
+    RecordRefund(i64),
+    RecordStipend(u64),
+    RecordDynamicCost {
+        gas_cost: u64,
+        memory_gas: u64,
+        gas_refund: i64,
+    },
+    RecordTransaction(u64),
+}
 
-    /// Run closure with provided listener.
-    pub fn using<R, F: FnOnce() -> R>(
-        listener: &mut (dyn EventListener + 'static),
-        f: F
-    ) -> R {
-        hook::using(listener, f)
+impl Event {
+    #[cfg(feature = "tracing")]
+    pub(crate) fn emit(self) {
+        hook::with(|hook| hook.event(self));
     }
 
-    pub(crate) fn with<F: FnOnce(&mut (dyn EventListener + 'static))>(
-        f: F
-    ) {
-        hook::with(f);
+    #[cfg(not(feature = "tracing"))]
+    pub(crate) fn emit(self) {
+        // no op.
     }
 }
 
+/// Run closure with provided listener.
 #[cfg(feature = "tracing")]
-pub use inner::using;
-
-#[cfg(not(feature = "tracing"))]
-macro_rules! event {
-    ($func_name: ident ( $($arg:expr),* )) => { }
-}
-
-#[cfg(feature = "tracing")]
-macro_rules! event {
-    ($method: ident ( $($arg:expr),* )) => {
-        $crate::tracing::inner::with(|hook| hook.$method( $($arg),* ));
-    }
+pub fn using<R, F: FnOnce() -> R>(
+    listener: &mut (dyn EventListener + 'static),
+    f: F
+) -> R {
+    hook::using(listener, f)
 }
\ No newline at end of file
diff --git a/runtime/Cargo.toml b/runtime/Cargo.toml
index 8f0668130..dbe7f5097 100644
--- a/runtime/Cargo.toml
+++ b/runtime/Cargo.toml
@@ -12,7 +12,11 @@ edition = "2018"
 evm-core = { version = "0.26", path = "../core", default-features = false }
 primitive-types = { version = "0.9", default-features = false }
 sha3 = { version = "0.8", default-features = false }
+environmental = { version = "1.1.2", default-features = false, optional = true}
 
 [features]
 default = ["std"]
-std = ["evm-core/std", "primitive-types/std", "sha3/std"]
+std = ["evm-core/std", "primitive-types/std", "sha3/std", "environmental/std"]
+tracing = [
+  "environmental"
+]
\ No newline at end of file
diff --git a/runtime/src/eval/system.rs b/runtime/src/eval/system.rs
index 7d3321063..e02b8e0c4 100644
--- a/runtime/src/eval/system.rs
+++ b/runtime/src/eval/system.rs
@@ -2,7 +2,7 @@ use core::cmp::min;
 use alloc::vec::Vec;
 use primitive_types::{H256, U256};
 use sha3::{Keccak256, Digest};
-use crate::{Runtime, ExitError, Handler, Capture, Transfer, ExitReason,
+use crate::{tracing, Runtime, ExitError, Handler, Capture, Transfer, ExitReason,
 			CreateScheme, CallScheme, Context, ExitSucceed, ExitFatal};
 use super::Control;
 
@@ -171,13 +171,27 @@ pub fn gaslimit<H: Handler>(runtime: &mut Runtime, handler: &H) -> Control<H> {
 
 pub fn sload<H: Handler>(runtime: &mut Runtime, handler: &H) -> Control<H> {
 	pop!(runtime, index);
-	push!(runtime, handler.storage(runtime.context.address, index));
+	let value = handler.storage(runtime.context.address, index);
+	push!(runtime, value);
+
+	tracing::Event::SLoad {
+		address: runtime.context.address,
+		index,
+		value
+	}.emit();
 
 	Control::Continue
 }
 
 pub fn sstore<H: Handler>(runtime: &mut Runtime, handler: &mut H) -> Control<H> {
 	pop!(runtime, index, value);
+
+	tracing::Event::SStore {
+		address: runtime.context.address,
+		index,
+		value
+	}.emit();
+
 	match handler.set_storage(runtime.context.address, index, value) {
 		Ok(()) => Control::Continue,
 		Err(e) => Control::Exit(e.into()),
diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
index 35b391769..439d778e2 100644
--- a/runtime/src/lib.rs
+++ b/runtime/src/lib.rs
@@ -1,16 +1,18 @@
 //! Runtime layer for EVM.
 
 #![deny(warnings)]
-#![forbid(unsafe_code, unused_variables, unused_imports)]
+#![forbid(unsafe_code, unused_variables)]
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
 
+
 mod eval;
 mod context;
 mod interrupt;
 mod handler;
+pub mod tracing;
 
 pub use evm_core::*;
 
@@ -24,6 +26,13 @@ use alloc::rc::Rc;
 macro_rules! step {
 	( $self:expr, $handler:expr, $return:tt $($err:path)?; $($ok:path)? ) => ({
 		if let Some((opcode, stack)) = $self.machine.inspect() {
+			tracing::Event::Step {
+				context: &$self.context,
+				opcode,
+				stack,
+				memory: $self.machine.memory()
+			}.emit();
+			
 			match $handler.pre_validate(&$self.context, opcode, stack) {
 				Ok(()) => (),
 				Err(e) => {
diff --git a/runtime/src/tracing.rs b/runtime/src/tracing.rs
new file mode 100644
index 000000000..65c589f58
--- /dev/null
+++ b/runtime/src/tracing.rs
@@ -0,0 +1,58 @@
+//! Allows to listen to runtime events.
+
+use crate::{Context, Opcode, Stack, Memory};
+use primitive_types::{H160, H256};
+
+
+
+#[cfg(feature = "tracing")]
+environmental::environmental!(hook: dyn EventListener + 'static);
+
+#[cfg(feature = "tracing")]
+pub trait EventListener {
+    fn event(
+        &mut self,
+        event: Event
+    );
+}
+
+#[derive(Debug, Copy, Clone)]
+pub enum Event<'a> {
+    Step {
+        context: &'a Context,
+        opcode: Opcode,
+        stack: &'a Stack,
+        memory: &'a Memory
+    },
+    SLoad {
+        address: H160,
+        index: H256,
+        value: H256
+    },
+    SStore {
+        address: H160,
+        index: H256,
+        value: H256
+    },
+}
+
+impl<'a> Event<'a> {
+    #[cfg(feature = "tracing")]
+    pub(crate) fn emit(self) {
+        hook::with(|hook| hook.event(self));
+    }
+
+    #[cfg(not(feature = "tracing"))]
+    pub(crate) fn emit(self) {
+        // no op.
+    }
+}
+
+/// Run closure with provided listener.
+#[cfg(feature = "tracing")]
+pub fn using<R, F: FnOnce() -> R>(
+    listener: &mut (dyn EventListener + 'static),
+    f: F
+) -> R {
+    hook::using(listener, f)
+}
\ No newline at end of file

From dccd2193f73245c22bd830784815629366454ed4 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Wed, 12 May 2021 11:54:04 +0000
Subject: [PATCH 05/15] add StepResult event

---
 runtime/src/lib.rs     | 6 +++++-
 runtime/src/tracing.rs | 3 ++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
index 439d778e2..6e10f70fd 100644
--- a/runtime/src/lib.rs
+++ b/runtime/src/lib.rs
@@ -50,7 +50,11 @@ macro_rules! step {
 			},
 		}
 
-		match $self.machine.step() {
+		let result = $self.machine.step();
+
+		tracing::Event::StepResult(&result).emit();
+
+		match result {
 			Ok(()) => $($ok)?(()),
 			Err(Capture::Exit(e)) => {
 				$self.status = Err(e.clone());
diff --git a/runtime/src/tracing.rs b/runtime/src/tracing.rs
index 65c589f58..612119234 100644
--- a/runtime/src/tracing.rs
+++ b/runtime/src/tracing.rs
@@ -1,6 +1,6 @@
 //! Allows to listen to runtime events.
 
-use crate::{Context, Opcode, Stack, Memory};
+use crate::{Context, Opcode, Stack, Memory, Capture, ExitReason, Trap};
 use primitive_types::{H160, H256};
 
 
@@ -24,6 +24,7 @@ pub enum Event<'a> {
         stack: &'a Stack,
         memory: &'a Memory
     },
+    StepResult (&'a Result<(), Capture<ExitReason, Trap>>),
     SLoad {
         address: H160,
         index: H256,

From 1f47c18ebfbf6c50eb0de87539fde8b79f50aea7 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Thu, 13 May 2021 14:09:47 +0000
Subject: [PATCH 06/15] more data in events

---
 gasometer/src/tracing.rs |  8 ++++----
 runtime/src/lib.rs       |  7 ++++++-
 runtime/src/tracing.rs   | 16 +++++++++-------
 3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/gasometer/src/tracing.rs b/gasometer/src/tracing.rs
index 2eba324b1..f962c3af7 100644
--- a/gasometer/src/tracing.rs
+++ b/gasometer/src/tracing.rs
@@ -1,7 +1,7 @@
 //! Allows to listen to gasometer events.
 
 #[cfg(feature = "tracing")]
-environmental::environmental!(hook: dyn EventListener + 'static);
+environmental::environmental!(listener: dyn EventListener + 'static);
 
 #[cfg(feature = "tracing")]
 pub trait EventListener {
@@ -27,7 +27,7 @@ pub enum Event {
 impl Event {
     #[cfg(feature = "tracing")]
     pub(crate) fn emit(self) {
-        hook::with(|hook| hook.event(self));
+        listener::with(|listener| listener.event(self));
     }
 
     #[cfg(not(feature = "tracing"))]
@@ -39,8 +39,8 @@ impl Event {
 /// Run closure with provided listener.
 #[cfg(feature = "tracing")]
 pub fn using<R, F: FnOnce() -> R>(
-    listener: &mut (dyn EventListener + 'static),
+    new: &mut (dyn EventListener + 'static),
     f: F
 ) -> R {
-    hook::using(listener, f)
+    listener::using(new, f)
 }
\ No newline at end of file
diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
index 6e10f70fd..611923235 100644
--- a/runtime/src/lib.rs
+++ b/runtime/src/lib.rs
@@ -29,6 +29,7 @@ macro_rules! step {
 			tracing::Event::Step {
 				context: &$self.context,
 				opcode,
+				position: $self.machine.position(),
 				stack,
 				memory: $self.machine.memory()
 			}.emit();
@@ -51,8 +52,12 @@ macro_rules! step {
 		}
 
 		let result = $self.machine.step();
+		let return_value = $self.machine.return_value();
 
-		tracing::Event::StepResult(&result).emit();
+		tracing::Event::StepResult {
+			result: &result,
+			return_value: &return_value,
+		}.emit();
 
 		match result {
 			Ok(()) => $($ok)?(()),
diff --git a/runtime/src/tracing.rs b/runtime/src/tracing.rs
index 612119234..623374c39 100644
--- a/runtime/src/tracing.rs
+++ b/runtime/src/tracing.rs
@@ -3,10 +3,8 @@
 use crate::{Context, Opcode, Stack, Memory, Capture, ExitReason, Trap};
 use primitive_types::{H160, H256};
 
-
-
 #[cfg(feature = "tracing")]
-environmental::environmental!(hook: dyn EventListener + 'static);
+environmental::environmental!(listener: dyn EventListener + 'static);
 
 #[cfg(feature = "tracing")]
 pub trait EventListener {
@@ -21,10 +19,14 @@ pub enum Event<'a> {
     Step {
         context: &'a Context,
         opcode: Opcode,
+        position: &'a Result<usize, ExitReason>,
         stack: &'a Stack,
         memory: &'a Memory
     },
-    StepResult (&'a Result<(), Capture<ExitReason, Trap>>),
+    StepResult {
+        result: &'a Result<(), Capture<ExitReason, Trap>>,
+        return_value: &'a [u8],
+    },
     SLoad {
         address: H160,
         index: H256,
@@ -40,7 +42,7 @@ pub enum Event<'a> {
 impl<'a> Event<'a> {
     #[cfg(feature = "tracing")]
     pub(crate) fn emit(self) {
-        hook::with(|hook| hook.event(self));
+        listener::with(|listener| listener.event(self));
     }
 
     #[cfg(not(feature = "tracing"))]
@@ -52,8 +54,8 @@ impl<'a> Event<'a> {
 /// Run closure with provided listener.
 #[cfg(feature = "tracing")]
 pub fn using<R, F: FnOnce() -> R>(
-    listener: &mut (dyn EventListener + 'static),
+    new: &mut (dyn EventListener + 'static),
     f: F
 ) -> R {
-    hook::using(listener, f)
+    listener::using(new, f)
 }
\ No newline at end of file

From c58502dd09da0ff2df50935e9dca291c4d8c87f6 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Mon, 17 May 2021 09:22:35 +0000
Subject: [PATCH 07/15] EVM events

---
 Cargo.toml                |  6 ++++-
 runtime/src/lib.rs        |  1 -
 src/executor/stack/mod.rs | 19 ++++++++++++-
 src/lib.rs                |  3 ++-
 src/tracing.rs            | 56 +++++++++++++++++++++++++++++++++++++++
 5 files changed, 81 insertions(+), 4 deletions(-)
 create mode 100644 src/tracing.rs

diff --git a/Cargo.toml b/Cargo.toml
index e888652d9..788c7009e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,6 +19,7 @@ primitive-types = { version = "0.9", default-features = false, features = ["rlp"
 serde = { version = "1.0", default-features = false, features = ["derive"], optional = true }
 codec = { package = "parity-scale-codec", version = "2.0", default-features = false, features = ["derive"], optional = true }
 ethereum = { version = "0.7", default-features = false }
+environmental = { version = "1.1.2", default-features = false, optional = true}
 
 [dev-dependencies]
 criterion = "0.3"
@@ -32,7 +33,10 @@ harness = false
 default = ["std"]
 with-codec = ["codec", "evm-core/with-codec", "primitive-types/codec", "ethereum/with-codec"]
 with-serde = ["serde", "evm-core/with-serde", "primitive-types/serde", "ethereum/with-serde"]
-std = ["evm-core/std", "evm-gasometer/std", "evm-runtime/std", "sha3/std", "primitive-types/std", "serde/std", "codec/std", "log/std", "ethereum/std"]
+std = ["evm-core/std", "evm-gasometer/std", "evm-runtime/std", "sha3/std", "primitive-types/std", "serde/std", "codec/std", "log/std", "ethereum/std", "environmental/std"]
+tracing = [
+  "environmental"
+]
 
 [workspace]
 members = [
diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
index 611923235..edc7ce25d 100644
--- a/runtime/src/lib.rs
+++ b/runtime/src/lib.rs
@@ -7,7 +7,6 @@
 
 extern crate alloc;
 
-
 mod eval;
 mod context;
 mod interrupt;
diff --git a/src/executor/stack/mod.rs b/src/executor/stack/mod.rs
index 8ff7ac508..8c5b51c17 100644
--- a/src/executor/stack/mod.rs
+++ b/src/executor/stack/mod.rs
@@ -7,7 +7,7 @@ use alloc::{rc::Rc, vec::Vec};
 use primitive_types::{U256, H256, H160};
 use sha3::{Keccak256, Digest};
 use crate::{ExitError, Stack, Opcode, Capture, Handler, Transfer,
-			Context, CreateScheme, Runtime, ExitReason, ExitSucceed, Config};
+			Context, CreateScheme, Runtime, ExitReason, ExitSucceed, Config, tracing};
 use crate::gasometer::{self, Gasometer};
 
 pub enum StackExitKind {
@@ -328,6 +328,14 @@ impl<'config, S: StackState<'config>> StackExecutor<'config, S> {
 			gas - gas / 64
 		}
 
+		tracing::Event::Create {
+			caller,
+			scheme,
+			value,
+			init_code: &init_code,
+			target_gas
+		}.emit();
+
 		if let Some(depth) = self.state.metadata().depth {
 			if depth > self.config.call_stack_limit {
 				return Capture::Exit((ExitError::CallTooDeep.into(), None, Vec::new()))
@@ -475,6 +483,15 @@ impl<'config, S: StackState<'config>> StackExecutor<'config, S> {
 			gas - gas / 64
 		}
 
+		tracing::Event::Call {
+			code_address,
+			transfer: &transfer,
+			input: &input,
+			target_gas,
+			is_static,
+			context: &context,
+		}.emit();
+
 		let after_gas = if take_l64 && self.config.call_l64_after_gas {
 			if self.config.estimate {
 				let initial_after_gas = self.state.metadata().gasometer.gas();
diff --git a/src/lib.rs b/src/lib.rs
index 612d4b845..9ff0c83ad 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,7 +1,7 @@
 //! Ethereum Virtual Machine implementation in Rust
 
 #![deny(warnings)]
-#![forbid(unsafe_code, unused_variables, unused_imports)]
+#![forbid(unsafe_code, unused_variables)]
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
@@ -13,3 +13,4 @@ pub use evm_gasometer as gasometer;
 
 pub mod executor;
 pub mod backend;
+pub mod tracing;
diff --git a/src/tracing.rs b/src/tracing.rs
new file mode 100644
index 000000000..9954f0f53
--- /dev/null
+++ b/src/tracing.rs
@@ -0,0 +1,56 @@
+//! Allows to listen to runtime events.
+
+use crate::{Context};
+use evm_runtime::{CreateScheme, Transfer};
+use primitive_types::{H160, U256};
+
+#[cfg(feature = "tracing")]
+environmental::environmental!(listener: dyn EventListener + 'static);
+
+#[cfg(feature = "tracing")]
+pub trait EventListener {
+    fn event(
+        &mut self,
+        event: Event
+    );
+}
+
+#[derive(Debug, Copy, Clone)]
+pub enum Event<'a> {
+    Call {
+        code_address: H160,
+		transfer: &'a Option<Transfer>,
+		input: &'a [u8],
+		target_gas: Option<u64>,
+		is_static: bool,
+		context: &'a Context,
+    },
+    Create {
+        caller: H160,
+		scheme: CreateScheme,
+		value: U256,
+		init_code: &'a [u8],
+		target_gas: Option<u64>,
+    }
+}
+
+impl<'a> Event<'a> {
+    #[cfg(feature = "tracing")]
+    pub(crate) fn emit(self) {
+        listener::with(|listener| listener.event(self));
+    }
+
+    #[cfg(not(feature = "tracing"))]
+    pub(crate) fn emit(self) {
+        // no op.
+    }
+}
+
+/// Run closure with provided listener.
+#[cfg(feature = "tracing")]
+pub fn using<R, F: FnOnce() -> R>(
+    new: &mut (dyn EventListener + 'static),
+    f: F
+) -> R {
+    listener::using(new, f)
+}
\ No newline at end of file

From 6c2569afe7deac9e4e2cb47ddab346e31c994fe6 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Tue, 18 May 2021 11:23:07 +0000
Subject: [PATCH 08/15] add snapshot of gasometer state in events

---
 gasometer/src/lib.rs     | 37 ++++++++++++++++++++++++++++++++-----
 gasometer/src/tracing.rs | 35 +++++++++++++++++++++++++++++++----
 2 files changed, 63 insertions(+), 9 deletions(-)

diff --git a/gasometer/src/lib.rs b/gasometer/src/lib.rs
index 634e5114b..4ba271f1e 100644
--- a/gasometer/src/lib.rs
+++ b/gasometer/src/lib.rs
@@ -116,7 +116,10 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		cost: u64,
 	) -> Result<(), ExitError> {
-		tracing::Event::RecordCost(cost).emit();
+		tracing::Event::RecordCost {
+			cost,
+			snapshot: self.snapshot()?,
+		}.emit();
 
 		let all_gas_cost = self.total_used_gas() + cost;
 		if self.gas_limit < all_gas_cost {
@@ -134,7 +137,10 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		refund: i64,
 	) -> Result<(), ExitError> {
-		tracing::Event::RecordRefund(refund).emit();
+		tracing::Event::RecordRefund {
+			refund,			
+			snapshot: self.snapshot()?,
+		}.emit();
 
 		self.inner_mut()?.refunded_gas += refund;
 		Ok(())
@@ -166,7 +172,12 @@ impl<'config> Gasometer<'config> {
 		let gas_refund = self.inner_mut()?.gas_refund(cost);
 		let used_gas = self.inner_mut()?.used_gas;
 
-		tracing::Event::RecordDynamicCost {gas_cost, memory_gas, gas_refund}.emit();
+		tracing::Event::RecordDynamicCost {
+			gas_cost,
+			memory_gas,
+			gas_refund, 
+			snapshot: self.snapshot()?,
+		}.emit();
 
 		let all_gas_cost = memory_gas + used_gas + gas_cost;
 		if self.gas_limit < all_gas_cost {
@@ -190,7 +201,10 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		stipend: u64,
 	) -> Result<(), ExitError> {
-		tracing::Event::RecordStipend(stipend).emit();
+		tracing::Event::RecordStipend {
+			stipend,
+			snapshot: self.snapshot()?,
+		}.emit();
 
 		self.inner_mut()?.used_gas -= stipend;
 		Ok(())
@@ -214,7 +228,10 @@ impl<'config> Gasometer<'config> {
 			},
 		};
 
-		tracing::Event::RecordTransaction(gas_cost).emit();
+		tracing::Event::RecordTransaction {
+			cost: gas_cost,
+			snapshot: self.snapshot()?,
+		}.emit();
 
 		if self.gas() < gas_cost {
 			self.inner = Err(ExitError::OutOfGas);
@@ -224,6 +241,16 @@ impl<'config> Gasometer<'config> {
 		self.inner_mut()?.used_gas += gas_cost;
 		Ok(())
 	}
+
+	fn snapshot(&self) -> Result<tracing::Snapshot, ExitError> {
+		let inner = self.inner.as_ref().map_err(|e| e.clone())?;
+		Ok(tracing::Snapshot {
+			gas_limit: self.gas_limit,
+			memory_gas: inner.memory_gas,
+			used_gas: inner.used_gas,
+			refunded_gas: inner.refunded_gas,
+		})
+	}
 }
 
 /// Calculate the call transaction cost.
diff --git a/gasometer/src/tracing.rs b/gasometer/src/tracing.rs
index f962c3af7..f60d5a587 100644
--- a/gasometer/src/tracing.rs
+++ b/gasometer/src/tracing.rs
@@ -11,17 +11,44 @@ pub trait EventListener {
     );
 }
 
+#[derive(Debug, Copy, Clone)]
+pub struct Snapshot {
+    pub gas_limit: u64,
+    pub memory_gas: u64,
+	pub used_gas: u64,
+	pub refunded_gas: i64,
+}
+
+impl Snapshot {
+    pub fn gas(&self) -> u64 {
+        self.gas_limit - self.used_gas - self.memory_gas
+    }
+}
+
 #[derive(Debug, Copy, Clone)]
 pub enum Event {
-    RecordCost(u64),
-    RecordRefund(i64),
-    RecordStipend(u64),
+    RecordCost {
+        cost: u64,
+        snapshot: Snapshot,
+    },
+    RecordRefund {
+        refund: i64,
+        snapshot: Snapshot,
+    },
+    RecordStipend {
+        stipend: u64,
+        snapshot: Snapshot,
+    },
     RecordDynamicCost {
         gas_cost: u64,
         memory_gas: u64,
         gas_refund: i64,
+        snapshot: Snapshot,
+    },
+    RecordTransaction {
+        cost: u64,
+        snapshot: Snapshot,
     },
-    RecordTransaction(u64),
 }
 
 impl Event {

From e1ac47c516f2f63df5629ee461cf24d59f73a9d3 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Tue, 18 May 2021 11:23:37 +0000
Subject: [PATCH 09/15] add create address + suicide event

---
 src/executor/stack/mod.rs | 12 ++++++++++--
 src/tracing.rs            |  8 +++++++-
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/src/executor/stack/mod.rs b/src/executor/stack/mod.rs
index 8c5b51c17..658843c7f 100644
--- a/src/executor/stack/mod.rs
+++ b/src/executor/stack/mod.rs
@@ -328,8 +328,11 @@ impl<'config, S: StackState<'config>> StackExecutor<'config, S> {
 			gas - gas / 64
 		}
 
+		let address = self.create_address(scheme);
+
 		tracing::Event::Create {
 			caller,
+			address,
 			scheme,
 			value,
 			init_code: &init_code,
@@ -366,7 +369,6 @@ impl<'config, S: StackState<'config>> StackExecutor<'config, S> {
 			self.state.metadata_mut().gasometer.record_cost(gas_limit)
 		);
 
-		let address = self.create_address(scheme);
 		self.state.inc_nonce(caller);
 
 		self.enter_substate(gas_limit, false);
@@ -659,9 +661,15 @@ impl<'config, S: StackState<'config>> Handler for StackExecutor<'config, S> {
 	fn mark_delete(&mut self, address: H160, target: H160) -> Result<(), ExitError> {
 		let balance = self.balance(address);
 
+		tracing::Event::Suicide {
+			target,
+			address,
+			balance,
+		}.emit();
+
 		self.state.transfer(Transfer {
 			source: address,
-			target: target,
+			target,
 			value: balance,
 		})?;
 		self.state.reset_balance(address);
diff --git a/src/tracing.rs b/src/tracing.rs
index 9954f0f53..431d121b5 100644
--- a/src/tracing.rs
+++ b/src/tracing.rs
@@ -27,11 +27,17 @@ pub enum Event<'a> {
     },
     Create {
         caller: H160,
+        address: H160,
 		scheme: CreateScheme,
 		value: U256,
 		init_code: &'a [u8],
 		target_gas: Option<u64>,
-    }
+    },
+    Suicide {
+        address: H160,
+		target: H160,
+        balance: U256,
+    },
 }
 
 impl<'a> Event<'a> {

From 5dfb3bdaad8bff2e1242bb7a4a47a17fef30b095 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Wed, 19 May 2021 09:47:26 +0000
Subject: [PATCH 10/15] runtime: use macro

---
 runtime/src/eval/system.rs | 10 +++++-----
 runtime/src/lib.rs         | 28 +++++++++++++++++++++-------
 runtime/src/tracing.rs     |  9 ---------
 3 files changed, 26 insertions(+), 21 deletions(-)

diff --git a/runtime/src/eval/system.rs b/runtime/src/eval/system.rs
index e02b8e0c4..ef5b5f7d4 100644
--- a/runtime/src/eval/system.rs
+++ b/runtime/src/eval/system.rs
@@ -2,7 +2,7 @@ use core::cmp::min;
 use alloc::vec::Vec;
 use primitive_types::{H256, U256};
 use sha3::{Keccak256, Digest};
-use crate::{tracing, Runtime, ExitError, Handler, Capture, Transfer, ExitReason,
+use crate::{Runtime, ExitError, Handler, Capture, Transfer, ExitReason,
 			CreateScheme, CallScheme, Context, ExitSucceed, ExitFatal};
 use super::Control;
 
@@ -174,11 +174,11 @@ pub fn sload<H: Handler>(runtime: &mut Runtime, handler: &H) -> Control<H> {
 	let value = handler.storage(runtime.context.address, index);
 	push!(runtime, value);
 
-	tracing::Event::SLoad {
+	event!(SLoad {
 		address: runtime.context.address,
 		index,
 		value
-	}.emit();
+	});
 
 	Control::Continue
 }
@@ -186,11 +186,11 @@ pub fn sload<H: Handler>(runtime: &mut Runtime, handler: &H) -> Control<H> {
 pub fn sstore<H: Handler>(runtime: &mut Runtime, handler: &mut H) -> Control<H> {
 	pop!(runtime, index, value);
 
-	tracing::Event::SStore {
+	event!(SStore {
 		address: runtime.context.address,
 		index,
 		value
-	}.emit();
+	});
 
 	match handler.set_storage(runtime.context.address, index, value) {
 		Ok(()) => Control::Continue,
diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
index edc7ce25d..6e5a2172e 100644
--- a/runtime/src/lib.rs
+++ b/runtime/src/lib.rs
@@ -7,11 +7,26 @@
 
 extern crate alloc;
 
+#[cfg(feature = "tracing")]
+pub mod tracing;
+
+#[cfg(feature = "tracing")]
+macro_rules! event {
+	($x:expr) => {
+		use tracing::Event::*;
+		$x.emit();
+	}
+}
+
+#[cfg(not(feature = "tracing"))]
+macro_rules! event {
+	($x:expr) => { }
+}
+
 mod eval;
 mod context;
 mod interrupt;
 mod handler;
-pub mod tracing;
 
 pub use evm_core::*;
 
@@ -25,13 +40,13 @@ use alloc::rc::Rc;
 macro_rules! step {
 	( $self:expr, $handler:expr, $return:tt $($err:path)?; $($ok:path)? ) => ({
 		if let Some((opcode, stack)) = $self.machine.inspect() {
-			tracing::Event::Step {
+			event!(Step {
 				context: &$self.context,
 				opcode,
 				position: $self.machine.position(),
 				stack,
 				memory: $self.machine.memory()
-			}.emit();
+			});
 			
 			match $handler.pre_validate(&$self.context, opcode, stack) {
 				Ok(()) => (),
@@ -51,12 +66,11 @@ macro_rules! step {
 		}
 
 		let result = $self.machine.step();
-		let return_value = $self.machine.return_value();
 
-		tracing::Event::StepResult {
+		event!(StepResult {
 			result: &result,
-			return_value: &return_value,
-		}.emit();
+			return_value: &$self.machine.return_value(),
+		});
 
 		match result {
 			Ok(()) => $($ok)?(()),
diff --git a/runtime/src/tracing.rs b/runtime/src/tracing.rs
index 623374c39..d83523ecd 100644
--- a/runtime/src/tracing.rs
+++ b/runtime/src/tracing.rs
@@ -3,10 +3,8 @@
 use crate::{Context, Opcode, Stack, Memory, Capture, ExitReason, Trap};
 use primitive_types::{H160, H256};
 
-#[cfg(feature = "tracing")]
 environmental::environmental!(listener: dyn EventListener + 'static);
 
-#[cfg(feature = "tracing")]
 pub trait EventListener {
     fn event(
         &mut self,
@@ -40,19 +38,12 @@ pub enum Event<'a> {
 }
 
 impl<'a> Event<'a> {
-    #[cfg(feature = "tracing")]
     pub(crate) fn emit(self) {
         listener::with(|listener| listener.event(self));
     }
-
-    #[cfg(not(feature = "tracing"))]
-    pub(crate) fn emit(self) {
-        // no op.
-    }
 }
 
 /// Run closure with provided listener.
-#[cfg(feature = "tracing")]
 pub fn using<R, F: FnOnce() -> R>(
     new: &mut (dyn EventListener + 'static),
     f: F

From e3695a1c8ff6443ede36c4f3bfe80b9c7fb0ed22 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Wed, 19 May 2021 11:21:53 +0000
Subject: [PATCH 11/15] update all events to macros

---
 gasometer/src/lib.rs      | 49 ++++++++++++++++++++++++++++-----------
 gasometer/src/tracing.rs  | 19 ++-------------
 runtime/src/lib.rs        |  2 +-
 src/executor/stack/mod.rs | 14 +++++------
 src/lib.rs                | 17 +++++++++++++-
 src/tracing.rs            |  9 -------
 6 files changed, 62 insertions(+), 48 deletions(-)

diff --git a/gasometer/src/lib.rs b/gasometer/src/lib.rs
index 4ba271f1e..328711939 100644
--- a/gasometer/src/lib.rs
+++ b/gasometer/src/lib.rs
@@ -5,11 +5,26 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
+#[cfg(feature = "tracing")]
+pub mod tracing;
+
+#[cfg(feature = "tracing")]
+macro_rules! event {
+	($x:expr) => {
+		use crate::tracing::Event::*;
+		$x.emit();
+	}
+}
+
+#[cfg(not(feature = "tracing"))]
+macro_rules! event {
+	($x:expr) => { }
+}
+
 mod consts;
 mod costs;
 mod memory;
 mod utils;
-pub mod tracing;
 
 use core::cmp::max;
 use primitive_types::{H160, H256, U256};
@@ -28,6 +43,14 @@ macro_rules! try_or_fail {
 	)
 }
 
+#[derive(Debug, Copy, Clone)]
+pub struct Snapshot {
+    pub gas_limit: u64,
+    pub memory_gas: u64,
+	pub used_gas: u64,
+	pub refunded_gas: i64,
+}
+
 /// EVM gasometer.
 #[derive(Clone)]
 pub struct Gasometer<'config> {
@@ -116,10 +139,10 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		cost: u64,
 	) -> Result<(), ExitError> {
-		tracing::Event::RecordCost {
+		event!(RecordCost {
 			cost,
 			snapshot: self.snapshot()?,
-		}.emit();
+		});
 
 		let all_gas_cost = self.total_used_gas() + cost;
 		if self.gas_limit < all_gas_cost {
@@ -137,10 +160,10 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		refund: i64,
 	) -> Result<(), ExitError> {
-		tracing::Event::RecordRefund {
+		event!(RecordRefund {
 			refund,			
 			snapshot: self.snapshot()?,
-		}.emit();
+		});
 
 		self.inner_mut()?.refunded_gas += refund;
 		Ok(())
@@ -172,12 +195,12 @@ impl<'config> Gasometer<'config> {
 		let gas_refund = self.inner_mut()?.gas_refund(cost);
 		let used_gas = self.inner_mut()?.used_gas;
 
-		tracing::Event::RecordDynamicCost {
+		event!(RecordDynamicCost {
 			gas_cost,
 			memory_gas,
 			gas_refund, 
 			snapshot: self.snapshot()?,
-		}.emit();
+		});
 
 		let all_gas_cost = memory_gas + used_gas + gas_cost;
 		if self.gas_limit < all_gas_cost {
@@ -201,10 +224,10 @@ impl<'config> Gasometer<'config> {
 		&mut self,
 		stipend: u64,
 	) -> Result<(), ExitError> {
-		tracing::Event::RecordStipend {
+		event!(RecordStipend {
 			stipend,
 			snapshot: self.snapshot()?,
-		}.emit();
+		});
 
 		self.inner_mut()?.used_gas -= stipend;
 		Ok(())
@@ -228,10 +251,10 @@ impl<'config> Gasometer<'config> {
 			},
 		};
 
-		tracing::Event::RecordTransaction {
+		event!(RecordTransaction {
 			cost: gas_cost,
 			snapshot: self.snapshot()?,
-		}.emit();
+		});
 
 		if self.gas() < gas_cost {
 			self.inner = Err(ExitError::OutOfGas);
@@ -242,9 +265,9 @@ impl<'config> Gasometer<'config> {
 		Ok(())
 	}
 
-	fn snapshot(&self) -> Result<tracing::Snapshot, ExitError> {
+	pub fn snapshot(&self) -> Result<Snapshot, ExitError> {
 		let inner = self.inner.as_ref().map_err(|e| e.clone())?;
-		Ok(tracing::Snapshot {
+		Ok(Snapshot {
 			gas_limit: self.gas_limit,
 			memory_gas: inner.memory_gas,
 			used_gas: inner.used_gas,
diff --git a/gasometer/src/tracing.rs b/gasometer/src/tracing.rs
index f60d5a587..480f03998 100644
--- a/gasometer/src/tracing.rs
+++ b/gasometer/src/tracing.rs
@@ -1,9 +1,9 @@
 //! Allows to listen to gasometer events.
 
-#[cfg(feature = "tracing")]
+use super::Snapshot;
+
 environmental::environmental!(listener: dyn EventListener + 'static);
 
-#[cfg(feature = "tracing")]
 pub trait EventListener {
     fn event(
         &mut self,
@@ -11,14 +11,6 @@ pub trait EventListener {
     );
 }
 
-#[derive(Debug, Copy, Clone)]
-pub struct Snapshot {
-    pub gas_limit: u64,
-    pub memory_gas: u64,
-	pub used_gas: u64,
-	pub refunded_gas: i64,
-}
-
 impl Snapshot {
     pub fn gas(&self) -> u64 {
         self.gas_limit - self.used_gas - self.memory_gas
@@ -52,19 +44,12 @@ pub enum Event {
 }
 
 impl Event {
-    #[cfg(feature = "tracing")]
     pub(crate) fn emit(self) {
         listener::with(|listener| listener.event(self));
     }
-
-    #[cfg(not(feature = "tracing"))]
-    pub(crate) fn emit(self) {
-        // no op.
-    }
 }
 
 /// Run closure with provided listener.
-#[cfg(feature = "tracing")]
 pub fn using<R, F: FnOnce() -> R>(
     new: &mut (dyn EventListener + 'static),
     f: F
diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
index 6e5a2172e..b23d2c2d7 100644
--- a/runtime/src/lib.rs
+++ b/runtime/src/lib.rs
@@ -13,7 +13,7 @@ pub mod tracing;
 #[cfg(feature = "tracing")]
 macro_rules! event {
 	($x:expr) => {
-		use tracing::Event::*;
+		use crate::tracing::Event::*;
 		$x.emit();
 	}
 }
diff --git a/src/executor/stack/mod.rs b/src/executor/stack/mod.rs
index 6bb99269d..280237429 100644
--- a/src/executor/stack/mod.rs
+++ b/src/executor/stack/mod.rs
@@ -7,7 +7,7 @@ use alloc::{rc::Rc, vec::Vec};
 use primitive_types::{U256, H256, H160};
 use sha3::{Keccak256, Digest};
 use crate::{ExitError, Stack, Opcode, Capture, Handler, Transfer,
-			Context, CreateScheme, Runtime, ExitReason, ExitSucceed, Config, tracing};
+			Context, CreateScheme, Runtime, ExitReason, ExitSucceed, Config};
 use ethereum::Log;
 use crate::gasometer::{self, Gasometer};
 
@@ -338,14 +338,14 @@ impl<'config, S: StackState<'config>> StackExecutor<'config, S> {
 
 		let address = self.create_address(scheme);
 
-		tracing::Event::Create {
+		event!(Create {
 			caller,
 			address,
 			scheme,
 			value,
 			init_code: &init_code,
 			target_gas
-		}.emit();
+		});
 
 		if let Some(depth) = self.state.metadata().depth {
 			if depth > self.config.call_stack_limit {
@@ -493,14 +493,14 @@ impl<'config, S: StackState<'config>> StackExecutor<'config, S> {
 			gas - gas / 64
 		}
 
-		tracing::Event::Call {
+		event!(Call {
 			code_address,
 			transfer: &transfer,
 			input: &input,
 			target_gas,
 			is_static,
 			context: &context,
-		}.emit();
+		});
 
 		let after_gas = if take_l64 && self.config.call_l64_after_gas {
 			if self.config.estimate {
@@ -678,11 +678,11 @@ impl<'config, S: StackState<'config>> Handler for StackExecutor<'config, S> {
 	fn mark_delete(&mut self, address: H160, target: H160) -> Result<(), ExitError> {
 		let balance = self.balance(address);
 
-		tracing::Event::Suicide {
+		event!(Suicide {
 			target,
 			address,
 			balance,
-		}.emit();
+		});
 
 		self.state.transfer(Transfer {
 			source: address,
diff --git a/src/lib.rs b/src/lib.rs
index 9ff0c83ad..395040a08 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -11,6 +11,21 @@ pub use evm_core::*;
 pub use evm_runtime::*;
 pub use evm_gasometer as gasometer;
 
+#[cfg(feature = "tracing")]
+pub mod tracing;
+
+#[cfg(feature = "tracing")]
+macro_rules! event {
+	($x:expr) => {
+		use crate::tracing::Event::*;
+		$x.emit();
+	}
+}
+
+#[cfg(not(feature = "tracing"))]
+macro_rules! event {
+	($x:expr) => { }
+}
+
 pub mod executor;
 pub mod backend;
-pub mod tracing;
diff --git a/src/tracing.rs b/src/tracing.rs
index 431d121b5..dcb083a6f 100644
--- a/src/tracing.rs
+++ b/src/tracing.rs
@@ -4,10 +4,8 @@ use crate::{Context};
 use evm_runtime::{CreateScheme, Transfer};
 use primitive_types::{H160, U256};
 
-#[cfg(feature = "tracing")]
 environmental::environmental!(listener: dyn EventListener + 'static);
 
-#[cfg(feature = "tracing")]
 pub trait EventListener {
     fn event(
         &mut self,
@@ -41,19 +39,12 @@ pub enum Event<'a> {
 }
 
 impl<'a> Event<'a> {
-    #[cfg(feature = "tracing")]
     pub(crate) fn emit(self) {
         listener::with(|listener| listener.event(self));
     }
-
-    #[cfg(not(feature = "tracing"))]
-    pub(crate) fn emit(self) {
-        // no op.
-    }
 }
 
 /// Run closure with provided listener.
-#[cfg(feature = "tracing")]
 pub fn using<R, F: FnOnce() -> R>(
     new: &mut (dyn EventListener + 'static),
     f: F

From 29b1d27f3ac6cba30b021f9a2e4c7cfefede604b Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Fri, 21 May 2021 10:39:47 +0000
Subject: [PATCH 12/15] editorconfig

---
 gasometer/src/lib.rs     | 6 +++---
 gasometer/src/tracing.rs | 2 +-
 runtime/src/lib.rs       | 2 +-
 runtime/src/tracing.rs   | 2 +-
 src/tracing.rs           | 2 +-
 5 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/gasometer/src/lib.rs b/gasometer/src/lib.rs
index 328711939..3cf608470 100644
--- a/gasometer/src/lib.rs
+++ b/gasometer/src/lib.rs
@@ -161,7 +161,7 @@ impl<'config> Gasometer<'config> {
 		refund: i64,
 	) -> Result<(), ExitError> {
 		event!(RecordRefund {
-			refund,			
+			refund,
 			snapshot: self.snapshot()?,
 		});
 
@@ -198,7 +198,7 @@ impl<'config> Gasometer<'config> {
 		event!(RecordDynamicCost {
 			gas_cost,
 			memory_gas,
-			gas_refund, 
+			gas_refund,
 			snapshot: self.snapshot()?,
 		});
 
@@ -259,7 +259,7 @@ impl<'config> Gasometer<'config> {
 		if self.gas() < gas_cost {
 			self.inner = Err(ExitError::OutOfGas);
 			return Err(ExitError::OutOfGas);
-		}		
+		}
 
 		self.inner_mut()?.used_gas += gas_cost;
 		Ok(())
diff --git a/gasometer/src/tracing.rs b/gasometer/src/tracing.rs
index 480f03998..c8901ccd8 100644
--- a/gasometer/src/tracing.rs
+++ b/gasometer/src/tracing.rs
@@ -55,4 +55,4 @@ pub fn using<R, F: FnOnce() -> R>(
     f: F
 ) -> R {
     listener::using(new, f)
-}
\ No newline at end of file
+}
diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
index b23d2c2d7..09e355f29 100644
--- a/runtime/src/lib.rs
+++ b/runtime/src/lib.rs
@@ -47,7 +47,7 @@ macro_rules! step {
 				stack,
 				memory: $self.machine.memory()
 			});
-			
+
 			match $handler.pre_validate(&$self.context, opcode, stack) {
 				Ok(()) => (),
 				Err(e) => {
diff --git a/runtime/src/tracing.rs b/runtime/src/tracing.rs
index d83523ecd..14252ece3 100644
--- a/runtime/src/tracing.rs
+++ b/runtime/src/tracing.rs
@@ -49,4 +49,4 @@ pub fn using<R, F: FnOnce() -> R>(
     f: F
 ) -> R {
     listener::using(new, f)
-}
\ No newline at end of file
+}
diff --git a/src/tracing.rs b/src/tracing.rs
index dcb083a6f..a33982ddf 100644
--- a/src/tracing.rs
+++ b/src/tracing.rs
@@ -50,4 +50,4 @@ pub fn using<R, F: FnOnce() -> R>(
     f: F
 ) -> R {
     listener::using(new, f)
-}
\ No newline at end of file
+}

From d248b177d55ff051f2061816e8feb56963b71c16 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Fri, 21 May 2021 10:41:46 +0000
Subject: [PATCH 13/15] fmt

---
 src/tracing.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/tracing.rs b/src/tracing.rs
index a33982ddf..039fce91c 100644
--- a/src/tracing.rs
+++ b/src/tracing.rs
@@ -1,6 +1,6 @@
 //! Allows to listen to runtime events.
 
-use crate::{Context};
+use crate::Context;
 use evm_runtime::{CreateScheme, Transfer};
 use primitive_types::{H160, U256};
 

From fbc7e8614a5bf226704d9e4a972e3c48ecb6be93 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Mon, 24 May 2021 11:31:10 +0000
Subject: [PATCH 14/15] fmt

---
 gasometer/Cargo.toml | 4 ++--
 gasometer/src/lib.rs | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/gasometer/Cargo.toml b/gasometer/Cargo.toml
index c3b7c1604..0a5c015f3 100644
--- a/gasometer/Cargo.toml
+++ b/gasometer/Cargo.toml
@@ -12,7 +12,7 @@ edition = "2018"
 primitive-types = { version = "0.9", default-features = false }
 evm-core = { version = "0.26", path = "../core", default-features = false }
 evm-runtime = { version = "0.26", path = "../runtime", default-features = false }
-environmental = { version = "1.1.2", default-features = false, optional = true}
+environmental = { version = "1.1.2", default-features = false, optional = true }
 
 [features]
 default = ["std"]
@@ -24,4 +24,4 @@ std = [
 ]
 tracing = [
   "environmental"
-]
\ No newline at end of file
+]
diff --git a/gasometer/src/lib.rs b/gasometer/src/lib.rs
index 3cf608470..790852055 100644
--- a/gasometer/src/lib.rs
+++ b/gasometer/src/lib.rs
@@ -45,8 +45,8 @@ macro_rules! try_or_fail {
 
 #[derive(Debug, Copy, Clone)]
 pub struct Snapshot {
-    pub gas_limit: u64,
-    pub memory_gas: u64,
+	pub gas_limit: u64,
+	pub memory_gas: u64,
 	pub used_gas: u64,
 	pub refunded_gas: i64,
 }

From 3e374474f4860a32d3ec61e58caf954d14d6e4f1 Mon Sep 17 00:00:00 2001
From: nanocryk <6422796+nanocryk@users.noreply.github.com>
Date: Wed, 26 May 2021 16:09:00 +0000
Subject: [PATCH 15/15] Update Cargo.toml

Co-authored-by: Wei Tang <accounts@that.world>
---
 Cargo.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index 788c7009e..eff67b880 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,7 +19,7 @@ primitive-types = { version = "0.9", default-features = false, features = ["rlp"
 serde = { version = "1.0", default-features = false, features = ["derive"], optional = true }
 codec = { package = "parity-scale-codec", version = "2.0", default-features = false, features = ["derive"], optional = true }
 ethereum = { version = "0.7", default-features = false }
-environmental = { version = "1.1.2", default-features = false, optional = true}
+environmental = { version = "1.1.2", default-features = false, optional = true }
 
 [dev-dependencies]
 criterion = "0.3"