bool MatchTaskCreationPattern(ILBlock method)
{
if (method.Body.Count < 5)
{
return(false);
}
// Check the second-to-last instruction (the start call) first, as we can get the most information from that
MethodReference startMethod;
ILExpression loadStartTarget, loadStartArgument;
// call(AsyncTaskMethodBuilder::Start, ldloca(builder), ldloca(stateMachine))
if (!method.Body[method.Body.Count - 2].Match(ILCode.Call, out startMethod, out loadStartTarget, out loadStartArgument))
{
return(false);
}
if (startMethod.Name != "Start" || startMethod.DeclaringType == null || startMethod.DeclaringType.Namespace != "System.Runtime.CompilerServices")
{
return(false);
}
switch (startMethod.DeclaringType.Name)
{
case "AsyncTaskMethodBuilder`1":
methodType = AsyncMethodType.TaskOfT;
break;
case "AsyncTaskMethodBuilder":
methodType = AsyncMethodType.Task;
break;
case "AsyncVoidMethodBuilder":
methodType = AsyncMethodType.Void;
break;
default:
return(false);
}
ILVariable stateMachineVar, builderVar;
if (!loadStartTarget.Match(ILCode.Ldloca, out builderVar))
{
return(false);
}
if (!loadStartArgument.Match(ILCode.Ldloca, out stateMachineVar))
{
return(false);
}
stateMachineStruct = stateMachineVar.Type.ResolveWithinSameModule();
if (stateMachineStruct == null || !stateMachineStruct.IsValueType)
{
return(false);
}
moveNextMethod = stateMachineStruct.Methods.FirstOrDefault(f => f.Name == "MoveNext");
if (moveNextMethod == null)
{
return(false);
}
// Check third-to-last instruction (copy of builder):
// stloc(builder, ldfld(StateMachine::<>t__builder, ldloca(stateMachine)))
ILExpression loadBuilderExpr;
if (!method.Body[method.Body.Count - 3].MatchStloc(builderVar, out loadBuilderExpr))
{
return(false);
}
FieldReference builderFieldRef;
ILExpression loadStateMachineForBuilderExpr;
if (!loadBuilderExpr.Match(ILCode.Ldfld, out builderFieldRef, out loadStateMachineForBuilderExpr))
{
return(false);
}
if (!loadStateMachineForBuilderExpr.MatchLdloca(stateMachineVar))
{
return(false);
}
builderField = builderFieldRef.ResolveWithinSameModule();
if (builderField == null)
{
return(false);
}
// Check the last instruction (ret)
if (methodType == AsyncMethodType.Void)
{
if (!method.Body[method.Body.Count - 1].Match(ILCode.Ret))
{
return(false);
}
}
else
{
// ret(call(AsyncTaskMethodBuilder::get_Task, ldflda(StateMachine::<>t__builder, ldloca(stateMachine))))
ILExpression returnValue;
if (!method.Body[method.Body.Count - 1].Match(ILCode.Ret, out returnValue))
{
return(false);
}
MethodReference getTaskMethod;
ILExpression builderExpr;
if (!returnValue.Match(ILCode.Call, out getTaskMethod, out builderExpr))
{
return(false);
}
ILExpression loadStateMachineForBuilderExpr2;
FieldReference builderField2;
if (!builderExpr.Match(ILCode.Ldflda, out builderField2, out loadStateMachineForBuilderExpr2))
{
return(false);
}
if (builderField2.ResolveWithinSameModule() != builderField || !loadStateMachineForBuilderExpr2.MatchLdloca(stateMachineVar))
{
return(false);
}
}
// Check the last field assignment - this should be the state field
ILExpression initialStateExpr;
if (!MatchStFld(method.Body[method.Body.Count - 4], stateMachineVar, out stateField, out initialStateExpr))
{
return(false);
}
if (!initialStateExpr.Match(ILCode.Ldc_I4, out initialState))
{
return(false);
}
if (initialState != -1)
{
return(false);
}
// Check the second-to-last field assignment - this should be the builder field
FieldDefinition builderField3;
ILExpression builderInitialization;
if (!MatchStFld(method.Body[method.Body.Count - 5], stateMachineVar, out builderField3, out builderInitialization))
{
return(false);
}
MethodReference createMethodRef;
if (builderField3 != builderField || !builderInitialization.Match(ILCode.Call, out createMethodRef))
{
return(false);
}
if (createMethodRef.Name != "Create")
{
return(false);
}
for (int i = 0; i < method.Body.Count - 5; i++)
{
FieldDefinition field;
ILExpression fieldInit;
if (!MatchStFld(method.Body[i], stateMachineVar, out field, out fieldInit))
{
return(false);
}
ILVariable v;
if (!fieldInit.Match(ILCode.Ldloc, out v))
{
return(false);
}
if (!v.IsParameter)
{
return(false);
}
fieldToParameterMap[field] = v;
}
return(true);
}
bool MatchTaskCreationPattern(ILBlock method)
{
if (method.Body.Count < 5)
return false;
// Check the second-to-last instruction (the start call) first, as we can get the most information from that
IMethod startMethod;
ILExpression loadStartTarget, loadStartArgument;
// call(AsyncTaskMethodBuilder::Start, ldloca(builder), ldloca(stateMachine))
if (!method.Body[method.Body.Count - 2].Match(ILCode.Call, out startMethod, out loadStartTarget, out loadStartArgument))
return false;
if (startMethod.Name != "Start" || startMethod.DeclaringType == null || startMethod.DeclaringType.Namespace != "System.Runtime.CompilerServices")
return false;
switch (startMethod.DeclaringType.Name) {
case "AsyncTaskMethodBuilder`1":
methodType = AsyncMethodType.TaskOfT;
break;
case "AsyncTaskMethodBuilder":
methodType = AsyncMethodType.Task;
break;
case "AsyncVoidMethodBuilder":
methodType = AsyncMethodType.Void;
break;
default:
return false;
}
ILVariable stateMachineVar, builderVar;
if (!loadStartTarget.Match(ILCode.Ldloca, out builderVar))
return false;
if (!loadStartArgument.Match(ILCode.Ldloca, out stateMachineVar))
return false;
stateMachineStruct = stateMachineVar.Type.GetTypeDefOrRef().ResolveWithinSameModule();
if (stateMachineStruct == null || !DnlibExtensions.IsValueType(stateMachineStruct))
return false;
moveNextMethod = stateMachineStruct.Methods.FirstOrDefault(f => f.Name == "MoveNext");
if (moveNextMethod == null)
return false;
// Check third-to-last instruction (copy of builder):
// stloc(builder, ldfld(StateMachine::<>t__builder, ldloca(stateMachine)))
ILExpression loadBuilderExpr;
if (!method.Body[method.Body.Count - 3].MatchStloc(builderVar, out loadBuilderExpr))
return false;
IField builderFieldRef;
ILExpression loadStateMachineForBuilderExpr;
if (!loadBuilderExpr.Match(ILCode.Ldfld, out builderFieldRef, out loadStateMachineForBuilderExpr))
return false;
if (!(loadStateMachineForBuilderExpr.MatchLdloca(stateMachineVar) || loadStateMachineForBuilderExpr.MatchLdloc(stateMachineVar)))
return false;
builderField = builderFieldRef.ResolveFieldWithinSameModule();
if (builderField == null)
return false;
// Check the last instruction (ret)
if (methodType == AsyncMethodType.Void) {
if (!method.Body[method.Body.Count - 1].Match(ILCode.Ret))
return false;
} else {
// ret(call(AsyncTaskMethodBuilder::get_Task, ldflda(StateMachine::<>t__builder, ldloca(stateMachine))))
ILExpression returnValue;
if (!method.Body[method.Body.Count - 1].Match(ILCode.Ret, out returnValue))
return false;
IMethod getTaskMethod;
ILExpression builderExpr;
if (!returnValue.Match(ILCode.Call, out getTaskMethod, out builderExpr))
return false;
ILExpression loadStateMachineForBuilderExpr2;
IField builderField2;
if (!builderExpr.Match(ILCode.Ldflda, out builderField2, out loadStateMachineForBuilderExpr2))
return false;
if (builderField2.ResolveFieldWithinSameModule() != builderField || !loadStateMachineForBuilderExpr2.MatchLdloca(stateMachineVar))
return false;
}
// Check the last field assignment - this should be the state field
ILExpression initialStateExpr;
if (!MatchStFld(method.Body[method.Body.Count - 4], stateMachineVar, out stateField, out initialStateExpr))
return false;
if (!initialStateExpr.Match(ILCode.Ldc_I4, out initialState))
return false;
if (initialState != -1)
return false;
// Check the second-to-last field assignment - this should be the builder field
FieldDef builderField3;
ILExpression builderInitialization;
if (!MatchStFld(method.Body[method.Body.Count - 5], stateMachineVar, out builderField3, out builderInitialization))
return false;
IMethod createMethodRef;
if (builderField3 != builderField || !builderInitialization.Match(ILCode.Call, out createMethodRef))
return false;
if (createMethodRef.Name != "Create")
return false;
for (int i = 0; i < method.Body.Count - 5; i++) {
FieldDef field;
ILExpression fieldInit;
if (!MatchStFld(method.Body[i], stateMachineVar, out field, out fieldInit))
return false;
ILVariable v;
if (!fieldInit.Match(ILCode.Ldloc, out v))
return false;
if (!v.IsParameter)
return false;
fieldToParameterMap[field] = v;
}
return true;
}
