Merge pull request #4967 from ethereum/const-opt-cost

Move dataGas calculation helper to GasMeter

3 files changed, 17 insertions, 10 deletions

diff --git a/libevmasm/ConstantOptimiser.cpp b/libevmasm/ConstantOptimiser.cpp
index 07ece12c..9844ba3a 100644
--- a/libevmasm/ConstantOptimiser.cpp
+++ b/libevmasm/ConstantOptimiser.cpp
@@ -94,15 +94,7 @@ bigint ConstantOptimisationMethod::simpleRunGas(AssemblyItems const& _items)
 bigint ConstantOptimisationMethod::dataGas(bytes const& _data) const
 {
 	assertThrow(_data.size() > 0, OptimizerException, "Empty bytecode generated.");
-	if (m_params.isCreation)
-	{
-		bigint gas;
-		for (auto b: _data)
-			gas += b ? GasCosts::txDataNonZeroGas : GasCosts::txDataZeroGas;
-		return gas;
-	}
-	else
-		return GasCosts::createDataGas * _data.size();
+	return bigint(GasMeter::dataGas(_data, m_params.isCreation));
 }
 
 size_t ConstantOptimisationMethod::bytesRequired(AssemblyItems const& _items)
diff --git a/libevmasm/GasMeter.cpp b/libevmasm/GasMeter.cpp
index caa06fc0..3554f809 100644
--- a/libevmasm/GasMeter.cpp
+++ b/libevmasm/GasMeter.cpp
@@ -258,4 +258,16 @@ unsigned GasMeter::runGas(Instruction _instruction)
 	return 0;
 }
 
-
+u256 GasMeter::dataGas(bytes const& _data, bool _inCreation)
+{
+	bigint gas = 0;
+	if (_inCreation)
+	{
+		for (auto b: _data)
+			gas += (b != 0) ? GasCosts::txDataNonZeroGas : GasCosts::txDataZeroGas;
+	}
+	else
+		gas = bigint(GasCosts::createDataGas) * _data.size();
+	assertThrow(gas < bigint(u256(-1)), OptimizerException, "Gas cost exceeds 256 bits.");
+	return u256(gas);
+}
diff --git a/libevmasm/GasMeter.h b/libevmasm/GasMeter.h
index fc3740d2..7cb8015f 100644
--- a/libevmasm/GasMeter.h
+++ b/libevmasm/GasMeter.h
@@ -136,6 +136,9 @@ public:
 	/// change with EVM versions)
 	static unsigned runGas(Instruction _instruction);
 
+	/// @returns the gas cost of the supplied data, depending whether it is in creation code, or not.
+	static u256 dataGas(bytes const& _data, bool _inCreation);
+
 private:
 	/// @returns _multiplier * (_value + 31) / 32, if _value is a known constant and infinite otherwise.
 	GasConsumption wordGas(u256 const& _multiplier, ExpressionClasses::Id _value);