From 56819e1de563e163b5c1ed981091248f4da28e20 Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Wed, 23 May 2018 12:41:33 +0200
Subject: [PATCH] core/evm: refactor CALL

---
 core/vm/evm.go | 79 +++++++++++++++++++++++++-------------------------
 1 file changed, 40 insertions(+), 39 deletions(-)

diff --git a/core/vm/evm.go b/core/vm/evm.go
index 3d1de43fe0..82002c71b7 100644
--- a/core/vm/evm.go
+++ b/core/vm/evm.go
@@ -168,9 +168,11 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
 		snapshot = evm.StateDB.Snapshot()
 	)
 	exists := evm.StateDB.Exist(addr)
+	precompile, isPrecompile := evm.BlockContext.Precompiles[addr]
+
 	if !exists{
-		if evm.BlockContext.Precompiles[addr] == nil && evm.ChainConfig().IsEIP158(evm.BlockContext.BlockNumber) && value.Sign() == 0 {
-			// Calling a non existing account, don't do antything, but ping the tracer
+		if !isPrecompile && evm.ChainConfig().IsEIP158(evm.BlockContext.BlockNumber) && value.Sign() == 0 {
+			// Calling a non existing account, don't do anything, but ping the tracer
 			if evm.vmConfig.Debug && evm.depth == 0 {
 				evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
 				evm.vmConfig.Tracer.CaptureEnd(ret, 0, 0, nil)
@@ -181,49 +183,48 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
 	}
 	evm.Transfer(evm.StateDB, caller.Address(), to.Address(), value)
 
-	precompile, isPrecompile := evm.BlockContext.Precompiles[addr]
-
-	if !exists && !isPrecompile{
-		// Shortcut execution -- account didn't exist,
-		// so no need to lookup the code
-		// but make sure to set returndata to nil
-		evm.interpreter.returnData = nil
-		return nil, gas, nil
-	}
-	code := evm.StateDB.GetCode(addr)
-	codeHash := evm.StateDB.GetCodeHash(addr)
-
-	if !isPrecompile && len(code) == 0 {
-		// Shortcut execution if there is no code,
-		// but make sure to set returndata to nil
-		evm.interpreter.returnData = nil
-		return nil, gas, nil
-	}
-
-	// Initialise a new contract and set the code that is to be used by the EVM.
-	// The contract is a scoped environment for this execution context only.
 	var contract *Contract
-
-	if!isPrecompile {
+	if isPrecompile{
+		// A 'contract' is needed for gas accounting
+		contract = NewPrecompiledContract(caller, to, value, gas)
+		ret, err = RunPrecompiledContract(precompile, input, contract)
+		// Capture the tracer start/end events in debug mode
+		if evm.vmConfig.Debug && evm.depth == 0 {
+			start := time.Now()
+			evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
+			defer func() { // Lazy evaluation of the parameters
+				evm.vmConfig.Tracer.CaptureEnd(ret, gas-contract.Gas, time.Since(start), err)
+			}()
+		}
+	}else{
+		if !exists{
+			// Shortcut execution -- account didn't exist,
+			// so no need to lookup the code
+			// but make sure to set returndata to nil
+			evm.interpreter.returnData = nil
+			return nil, gas, nil
+		}
+		code := evm.StateDB.GetCode(addr)
+		if len(code) == 0 {
+			// Shortcut execution if there is no code,
+			// but make sure to set returndata to nil
+			evm.interpreter.returnData = nil
+			return nil, gas, nil
+		}
+		codeHash := evm.StateDB.GetCodeHash(addr)
 		contract = NewContract(caller, to, value, gas)
 		contract.SetCallCode(&addr, codeHash, code)
-	}else{
-		contract = NewPrecompiledContract(caller, to, value, gas)
-	}
-	// Capture the tracer start/end events in debug mode
-	if evm.vmConfig.Debug && evm.depth == 0 {
-		start := time.Now()
-		evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
 
-		defer func() { // Lazy evaluation of the parameters
-			evm.vmConfig.Tracer.CaptureEnd(ret, gas-contract.Gas, time.Since(start), err)
-		}()
-	}
+		// Capture the tracer start/end events in debug mode
+		if evm.vmConfig.Debug && evm.depth == 0 {
+			start := time.Now()
+			evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
 
-	if!isPrecompile{
+			defer func() { // Lazy evaluation of the parameters
+				evm.vmConfig.Tracer.CaptureEnd(ret, gas-contract.Gas, time.Since(start), err)
+			}()
+		}
 		ret, err = evm.interpreter.Run(contract, input)
-	}else{
-		ret, err = RunPrecompiledContract(precompile, input, contract)
 	}
 	// When an error was returned by the EVM or when setting the creation code
 	// above we revert to the snapshot and consume any gas remaining. Additionally