From 7e5de5f5c79361742820f6634bfb469bf476dcc1 Mon Sep 17 00:00:00 2001
From: Tomusdrw <tomusdrw@gmail.com>
Date: Thu, 14 Jan 2016 01:31:45 +0100
Subject: [PATCH] More descriptive interpreter errors

---
 src/evm/evm.rs         | 12 ++++++++++--
 src/evm/factory.rs     |  2 +-
 src/evm/interpreter.rs | 12 ++++++++++--
 src/evm/tests.rs       |  4 ++--
 src/executive.rs       |  4 ++--
 5 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/src/evm/evm.rs b/src/evm/evm.rs
index 589af13a5..fd87efd32 100644
--- a/src/evm/evm.rs
+++ b/src/evm/evm.rs
@@ -19,9 +19,17 @@ pub enum Error {
 	BadInstruction,
 	/// `StackUnderflow` when there is not enough stack elements to execute instruction
 	/// First parameter says how many elements were needed and the second how many were actually on Stack
-	StackUnderflow(/*wanted*/usize, /*on_stack*/usize),
+	StackUnderflow {
+		instruction: &'static str,
+		wanted: usize, 
+		on_stack: usize
+	},
 	/// When execution would exceed defined Stack Limit
-	OutOfStack(/*wanted*/usize, /*stack_limit*/usize),
+	OutOfStack {
+		instruction: &'static str,
+		wanted: usize, 
+		limit: usize
+	},
 	/// Returned on evm internal error. Should never be ignored during development.
 	/// Likely to cause consensus issues.
 	Internal,
diff --git a/src/evm/factory.rs b/src/evm/factory.rs
index 67ffe9766..39019cd8d 100644
--- a/src/evm/factory.rs
+++ b/src/evm/factory.rs
@@ -15,7 +15,7 @@ impl Factory {
 	/// Returns native rust evm
 	#[cfg(not(feature = "jit"))]
 	pub fn create() -> Box<Evm> {
-		Box::new(super::interpreter::Interpreter::new())
+		Box::new(super::interpreter::Interpreter)
 	}
 }
 
diff --git a/src/evm/interpreter.rs b/src/evm/interpreter.rs
index bbe5a45e1..786277b83 100644
--- a/src/evm/interpreter.rs
+++ b/src/evm/interpreter.rs
@@ -626,9 +626,17 @@ impl Interpreter {
 																			stack_limit: usize, 
 																			stack: &Stack<U256>) -> Result<(), evm::Error> {
 		if !stack.has(info.args) {
-			Err(evm::Error::StackUnderflow(info.args, stack.size()))
+			Err(evm::Error::StackUnderflow {
+				instruction: info.name,
+				wanted: info.args, 
+				on_stack: stack.size()
+			})
 		} else if stack.size() - info.args + info.ret > stack_limit {
-			Err(evm::Error::OutOfStack(info.ret - info.args, stack_limit))
+			Err(evm::Error::OutOfStack {
+				instruction: info.name,
+				wanted: info.ret - info.args, 
+				limit: stack_limit
+			})
 		} else {
 			Ok(())
 		}
diff --git a/src/evm/tests.rs b/src/evm/tests.rs
index 3d29464fe..ab5dd9dbd 100644
--- a/src/evm/tests.rs
+++ b/src/evm/tests.rs
@@ -112,9 +112,9 @@ fn test_stack_underflow() {
 	};
 	
 	match err {
-		evm::Error::StackUnderflow(wanted, stack) => {
+		evm::Error::StackUnderflow {instruction: _, wanted, on_stack} => {
 			assert_eq!(wanted, 2);
-			assert_eq!(stack, 0);
+			assert_eq!(on_stack, 0);
 		}
 		_ => {
 			assert!(false, "Expected StackUndeflow")
diff --git a/src/executive.rs b/src/executive.rs
index 97dea7b05..23782e314 100644
--- a/src/executive.rs
+++ b/src/executive.rs
@@ -221,8 +221,8 @@ impl<'a> Executive<'a> {
 			Err(evm::Error::OutOfGas) 
 				| Err(evm::Error::BadJumpDestination) 
 				| Err(evm::Error::BadInstruction) 
-				| Err(evm::Error::StackUnderflow(_, _))
-				| Err(evm::Error::OutOfStack(_, _)) => {
+				| Err(evm::Error::StackUnderflow {instruction: _, wanted: _, on_stack: _})
+				| Err(evm::Error::OutOfStack {instruction: _, wanted: _, limit: _}) => {
 				*self.state = backup;
 				Ok(Executed {
 					gas: t.gas,