public DynamicMethod RecompileMethod(Cecil.MethodDefinition methodDef)
{
Debug.Trace("Recompiling method: {0}", methodDef.FullName);
var declaringType = FindType(methodDef.DeclaringType);
var returnType = FindType(methodDef.ReturnType);
Type[] paramTypes = methodDef.Parameters.Select((paramDef) => {
return(FindType(paramDef.ParameterType));
}).ToArray();
if (!methodDef.IsStatic)
{
paramTypes = new Type[] { declaringType }.Concat(paramTypes).ToArray();
}
var dynMethod = new DynamicMethod(methodDef.Name, returnType, paramTypes, true);
ILGenerator il = dynMethod.GetILGenerator();
dynMethod.InitLocals = methodDef.Body.InitLocals;
foreach (var variable in methodDef.Body.Variables)
{
var localType = FindType(variable.VariableType);
Debug.Trace("Declaring local (cecil type: {0}) of type (runtime type: {1})", variable.VariableType, localType);
il.DeclareLocal(localType);
}
var labels = new Dictionary <Cecil.Cil.Instruction, Label>();
foreach (var inst in methodDef.Body.Instructions)
{
if (inst.Operand != null && inst.Operand.GetType() == typeof(Cecil.Cil.Instruction))
{
var opinst = (Cecil.Cil.Instruction)(inst.Operand);
labels[opinst] = il.DefineLabel();
}
}
foreach (var inst in Instrument.IterateInstructions(methodDef))
{
Debug.Trace("Emitting: {0}", inst);
Label label;
if (labels.TryGetValue(inst, out label))
{
il.MarkLabel(label);
}
var ilop = FindOpcode(inst.OpCode);
if (inst.Operand != null)
{
var operand = inst.Operand;
var operandType = operand.GetType();
// Dynamic dispatch implementation:
// We have to run different processing code depending on the type of instruction
// operand. Visitor pattern cannot be implemented here, because we don't actually
// own the classes that are the operands (and some of them are primitive or system
// types).
// Therefore, dynamic dispatcher is used. Method for each operand type is implemented
// in this class, and reflection is used to find correct method to call.
// In newer .net versions we would be able to do EmitInstruction(il, ilop, (dynamic)operand),
// but the .net version we are targeting (because of Unity compatibility) does not
// have `dynamic`.
if (operandType == typeof(Cecil.Cil.Instruction))
{
//branch location
var operandInst = (Cecil.Cil.Instruction)operand;
il.Emit(ilop, labels[operandInst]);
}
else if (primitiveOperandTypes.Contains(operandType))
{
//if operand is primitive, call il.Emit directly
Reflection.MethodInfo method;
if (!EmitPrimitiveCache.TryGetValue(operandType, out method))
{
method = typeof(ILGenerator).GetMethod("Emit", new Type[] { typeof(OpCode), operandType });
EmitPrimitiveCache[operandType] = method;
}
if (method == null)
{
throw new Exception(String.Format("Emit method for primitive type {0} not found.", operandType.Name));
}
method.Invoke(il, new object[] { ilop, operand });
}
else
{
//or else, call our EmitInstruction
Reflection.MethodInfo method;
if (!EmitInstructionCache.TryGetValue(operandType, out method))
{
method = GetType().GetMethod("EmitInstruction",
bindingAttr: bflags_all_instance,
binder: null,
modifiers: null,
types: new Type[] { typeof(ILGenerator), typeof(OpCode), operandType });
EmitInstructionCache[operandType] = method;
}
if (method == null)
{
throw new Exception(String.Format("Don't know what to do with operand {0}", operandType.Name));
}
method.Invoke(this, new object[] { il, ilop, operand });
}
}
else
{
il.Emit(ilop);
}
}
return(dynMethod);
}
public void HotPatch(string assemblyFilename)
{
Debug.Trace("Started hotpatching {0}", assemblyFilename);
var newAssembly = Cecil.AssemblyDefinition.ReadAssembly(assemblyFilename);
foreach (var method in IterateMethods(newAssembly))
{
Debug.Trace($"Searching for {method.FullName}");
LocalMethod localMethod;
if (!localMethods.TryGetValue(method.FullName, out localMethod))
{
Debug.Trace($"Did not find loaded method {method.FullName}. New method or a bug.");
continue;
}
string newBody = ConcatBody(method);
int newBodyHash = newBody.GetHashCode();
if (localMethod.BodyHashCode == newBody.GetHashCode())
{
Debug.Trace($"Found {method.FullName}, but hash code didn't change.");
continue;
}
string oldBody = localMethod.BodyString;
Debug.Log($"<i>Trying to hotpatch {method.FullName}...</i>");
if (localMethod.Method == null)
{
Debug.Log($"Can't hotpatch {method.FullName} - local method not found,");
continue;
}
Debug.Trace("----------");
Debug.Trace("Hotswapping {0}", method.FullName);
Debug.Trace("Method body hashcode was: {0}, is: {1}", localMethod.BodyHashCode, newBodyHash);
Debug.Trace("Method body was:");
Debug.Trace(oldBody);
Debug.Trace("Method body is:");
Debug.Trace(newBody);
try {
var dynmethod = recompiler.RecompileMethod(method);
if (dynmethod != null)
{
SwapMethod(localMethod.Method, dynmethod);
localMethod.CurrentSwap = dynmethod;
localMethod.BodyString = newBody;
localMethod.BodyHashCode = newBodyHash;
}
}
catch (Exception e) {
Debug.LogWarningFormat("Failed to patch {0}. <i>See full stacktrace in Temp/hotpatch.log.</i>\nError is: {1}",
method.FullName, e.Message);
Debug.Trace(e.StackTrace);
}
finally {
Debug.Trace("----------");
}
}
}
