Allow selecting VM kind manually

evmjit/libevmjit-cpp/JitVM.cpp

@@ -32,9 +32,7 @@ bytesConstRef JitVM::go(ExtVMFace& _ext, OnOpFunc const& _onOp, uint64_t _step)
 	if (rejected)
 	{
 		cwarn << "Execution rejected by EVM JIT (gas limit: " << m_gas << "), executing with interpreter";
-		VMFactory::setKind(VMKind::Interpreter);
+		m_fallbackVM = VMFactory::create(VMKind::Interpreter, m_gas);
-		m_fallbackVM = VMFactory::create(m_gas);
-		VMFactory::setKind(VMKind::JIT);
 		auto&& output = m_fallbackVM->go(_ext, _onOp, _step);
 		m_gas = m_fallbackVM->gas(); // copy remaining gas, Executive expects it
 		return output;

libevm/VMFactory.cpp

@@ -29,7 +29,7 @@ namespace eth
 {
 namespace
 {
-	VMKind g_kind = VMKind::Interpreter;
+	auto g_kind = VMKind::Interpreter;
 }
 
 void VMFactory::setKind(VMKind _kind)
@@ -38,11 +38,16 @@ void VMFactory::setKind(VMKind _kind)
 }
 
 std::unique_ptr<VMFace> VMFactory::create(u256 _gas)
+{
+	return create(g_kind, _gas);
+}
+
+std::unique_ptr<VMFace> VMFactory::create(VMKind _kind, u256 _gas)
 {
 #if ETH_EVMJIT
-	return std::unique_ptr<VMFace>(g_kind == VMKind::JIT ? static_cast<VMFace*>(new JitVM(_gas)) : static_cast<VMFace*>(new VM(_gas)));
+	return std::unique_ptr<VMFace>(_kind == VMKind::JIT ? static_cast<VMFace*>(new JitVM(_gas)) : static_cast<VMFace*>(new VM(_gas)));
 #else
-	asserts(g_kind == VMKind::Interpreter && "JIT disabled in build configuration");
+	asserts(_kind == VMKind::Interpreter && "JIT disabled in build configuration");
 	return std::unique_ptr<VMFace>(new VM(_gas));
 #endif
 }

libevm/VMFactory.h

@@ -26,7 +26,7 @@ namespace eth
 enum class VMKind: bool
 {
 	Interpreter,
-	JIT
+	JIT,
 };
 
 class VMFactory
@@ -34,7 +34,13 @@ class VMFactory
 public:
 	VMFactory() = delete;
 
+	/// Creates a VM instance of global kind (controlled by setKind() function).
 	static std::unique_ptr<VMFace> create(u256 _gas);
+
+	/// Creates a VM instance of kind provided.
+	static std::unique_ptr<VMFace> create(VMKind _kind, u256 _gas);
+
+	/// Set global VM kind
 	static void setKind(VMKind _kind);
 };