Merge pull request #5089 from ethereum/gasmeter

Small pathgasmeter cleanups

4 files changed, 16 insertions, 5 deletions

diff --git a/libevmasm/GasMeter.cpp b/libevmasm/GasMeter.cpp
index b525c301..b40617c1 100644
--- a/libevmasm/GasMeter.cpp
+++ b/libevmasm/GasMeter.cpp
@@ -101,8 +101,8 @@ GasMeter::GasConsumption GasMeter::estimateMax(AssemblyItem const& _item, bool _
 			break;
 		case Instruction::KECCAK256:
 			gas = GasCosts::keccak256Gas;
-			gas += wordGas(GasCosts::keccak256WordGas, m_state->relativeStackElement(-1));
 			gas += memoryGas(0, -1);
+			gas += wordGas(GasCosts::keccak256WordGas, m_state->relativeStackElement(-1));
 			break;
 		case Instruction::CALLDATACOPY:
 		case Instruction::CODECOPY:
@@ -214,7 +214,7 @@ GasMeter::GasConsumption GasMeter::memoryGas(ExpressionClasses::Id _position)
 	if (!value)
 		return GasConsumption::infinite();
 	if (*value < m_largestMemoryAccess)
-		return GasConsumption(u256(0));
+		return GasConsumption(0);
 	u256 previous = m_largestMemoryAccess;
 	m_largestMemoryAccess = *value;
 	auto memGas = [=](u256 const& pos) -> u256
diff --git a/libevmasm/GasMeter.h b/libevmasm/GasMeter.h
index 7cb8015f..da90b028 100644
--- a/libevmasm/GasMeter.h
+++ b/libevmasm/GasMeter.h
@@ -137,6 +137,8 @@ public:
 	static unsigned runGas(Instruction _instruction);
 
 	/// @returns the gas cost of the supplied data, depending whether it is in creation code, or not.
+	/// In case of @a _inCreation, the data is only sent as a transaction and is not stored, whereas
+	/// otherwise code will be stored and have to pay "createDataGas" cost.
 	static u256 dataGas(bytes const& _data, bool _inCreation);
 
 private:
diff --git a/libevmasm/PathGasMeter.h b/libevmasm/PathGasMeter.h
index 9537b176..fb821684 100644
--- a/libevmasm/PathGasMeter.h
+++ b/libevmasm/PathGasMeter.h
@@ -57,6 +57,16 @@ public:
 
 	GasMeter::GasConsumption estimateMax(size_t _startIndex, std::shared_ptr<KnownState> const& _state);
 
+	static GasMeter::GasConsumption estimateMax(
+		AssemblyItems const& _items,
+		solidity::EVMVersion _evmVersion,
+		size_t _startIndex,
+		std::shared_ptr<KnownState> const& _state
+	)
+	{
+		return PathGasMeter(_items, _evmVersion).estimateMax(_startIndex, _state);
+	}
+
 private:
 	/// Adds a new path item to the queue, but only if we do not already have
 	/// a higher gas usage at that point.
diff --git a/libsolidity/interface/GasEstimator.cpp b/libsolidity/interface/GasEstimator.cpp
index a532f86e..e70e23a2 100644
--- a/libsolidity/interface/GasEstimator.cpp
+++ b/libsolidity/interface/GasEstimator.cpp
@@ -160,8 +160,7 @@ GasEstimator::GasConsumption GasEstimator::functionalEstimation(
 		);
 	}
 
-	PathGasMeter meter(_items, m_evmVersion);
-	return meter.estimateMax(0, state);
+	return PathGasMeter::estimateMax(_items, m_evmVersion, 0, state);
 }
 
 GasEstimator::GasConsumption GasEstimator::functionalEstimation(
@@ -183,7 +182,7 @@ GasEstimator::GasConsumption GasEstimator::functionalEstimation(
 	if (parametersSize > 0)
 		state->feedItem(swapInstruction(parametersSize));
 
-	return PathGasMeter(_items, m_evmVersion).estimateMax(_offset, state);
+	return PathGasMeter::estimateMax(_items, m_evmVersion, _offset, state);
 }
 
 set<ASTNode const*> GasEstimator::finestNodesAtLocation(