void AnalyzeMoveNext()
{
MethodDefinition moveNextMethod = enumeratorType.Methods.FirstOrDefault(m => m.Name == "MoveNext");
ILBlock ilMethod = CreateILAst(moveNextMethod);
if (ilMethod.Body.Count == 0)
{
throw new YieldAnalysisFailedException();
}
ILExpression lastReturnArg;
if (!ilMethod.Body.Last().Match(ILCode.Ret, out lastReturnArg))
{
throw new YieldAnalysisFailedException();
}
// There are two possibilities:
if (lastReturnArg.Code == ILCode.Ldloc)
{
// a) the compiler uses a variable for returns (in debug builds, or when there are try-finally blocks)
returnVariable = (ILVariable)lastReturnArg.Operand;
returnLabel = ilMethod.Body.ElementAtOrDefault(ilMethod.Body.Count - 2) as ILLabel;
if (returnLabel == null)
{
throw new YieldAnalysisFailedException();
}
}
else
{
// b) the compiler directly returns constants
returnVariable = null;
returnLabel = null;
// In this case, the last return must return false.
if (lastReturnArg.Code != ILCode.Ldc_I4 || (int)lastReturnArg.Operand != 0)
{
throw new YieldAnalysisFailedException();
}
}
ILTryCatchBlock tryFaultBlock = ilMethod.Body[0] as ILTryCatchBlock;
List <ILNode> body;
int bodyLength;
if (tryFaultBlock != null)
{
// there are try-finally blocks
if (returnVariable == null) // in this case, we must use a return variable
{
throw new YieldAnalysisFailedException();
}
// must be a try-fault block:
if (tryFaultBlock.CatchBlocks.Count != 0 || tryFaultBlock.FinallyBlock != null || tryFaultBlock.FaultBlock == null)
{
throw new YieldAnalysisFailedException();
}
ILBlock faultBlock = tryFaultBlock.FaultBlock;
// Ensure the fault block contains the call to Dispose().
if (faultBlock.Body.Count != 2)
{
throw new YieldAnalysisFailedException();
}
MethodReference disposeMethodRef;
ILExpression disposeArg;
if (!faultBlock.Body[0].Match(ILCode.Call, out disposeMethodRef, out disposeArg))
{
throw new YieldAnalysisFailedException();
}
if (GetMethodDefinition(disposeMethodRef) != disposeMethod || !disposeArg.MatchThis())
{
throw new YieldAnalysisFailedException();
}
if (!faultBlock.Body[1].Match(ILCode.Endfinally))
{
throw new YieldAnalysisFailedException();
}
body = tryFaultBlock.TryBlock.Body;
bodyLength = body.Count;
}
else
{
// no try-finally blocks
body = ilMethod.Body;
if (returnVariable == null)
{
bodyLength = body.Count - 1; // all except for the return statement
}
else
{
bodyLength = body.Count - 2; // all except for the return label and statement
}
}
// Now verify that the last instruction in the body is 'ret(false)'
if (returnVariable != null)
{
// If we don't have a return variable, we already verified that above.
// If we do have one, check for 'stloc(returnVariable, ldc.i4(0))'
// Maybe might be a jump to the return label after the stloc:
ILExpression leave = body.ElementAtOrDefault(bodyLength - 1) as ILExpression;
if (leave != null && (leave.Code == ILCode.Br || leave.Code == ILCode.Leave) && leave.Operand == returnLabel)
{
bodyLength--;
}
ILExpression store0 = body.ElementAtOrDefault(bodyLength - 1) as ILExpression;
if (store0 == null || store0.Code != ILCode.Stloc || store0.Operand != returnVariable)
{
throw new YieldAnalysisFailedException();
}
if (store0.Arguments[0].Code != ILCode.Ldc_I4 || (int)store0.Arguments[0].Operand != 0)
{
throw new YieldAnalysisFailedException();
}
bodyLength--; // don't conside the stloc instruction to be part of the body
}
// verify that the last element in the body is a label pointing to the 'ret(false)'
returnFalseLabel = body.ElementAtOrDefault(bodyLength - 1) as ILLabel;
if (returnFalseLabel == null)
{
throw new YieldAnalysisFailedException();
}
InitStateRanges(body[0]);
int pos = AssignStateRanges(body, bodyLength, forDispose: false);
if (pos > 0 && body[pos - 1] is ILLabel)
{
pos--;
}
else
{
// ensure that the first element at body[pos] is a label:
ILLabel newLabel = new ILLabel();
newLabel.Name = "YieldReturnEntryPoint";
ranges[newLabel] = ranges[body[pos]]; // give the label the range of the instruction at body[pos]
body.Insert(pos, newLabel);
bodyLength++;
}
List <KeyValuePair <ILLabel, StateRange> > labels = new List <KeyValuePair <ILLabel, StateRange> >();
for (int i = pos; i < bodyLength; i++)
{
ILLabel label = body[i] as ILLabel;
if (label != null)
{
labels.Add(new KeyValuePair <ILLabel, StateRange>(label, ranges[label]));
}
}
ConvertBody(body, pos, bodyLength, labels);
}
void ConvertBody(List <ILNode> body, int startPos, int bodyLength, List <KeyValuePair <ILLabel, StateRange> > labels)
{
newBody = new List <ILNode>();
newBody.Add(MakeGoTo(labels, 0));
List <SetState> stateChanges = new List <SetState>();
int currentState = -1;
// Copy all instructions from the old body to newBody.
for (int pos = startPos; pos < bodyLength; pos++)
{
ILExpression expr = body[pos] as ILExpression;
if (expr != null && expr.Code == ILCode.Stfld && expr.Arguments[0].MatchThis())
{
// Handle stores to 'state' or 'current'
if (GetFieldDefinition(expr.Operand as FieldReference) == stateField)
{
if (expr.Arguments[1].Code != ILCode.Ldc_I4)
{
throw new YieldAnalysisFailedException();
}
currentState = (int)expr.Arguments[1].Operand;
stateChanges.Add(new SetState(newBody.Count, currentState));
}
else if (GetFieldDefinition(expr.Operand as FieldReference) == currentField)
{
newBody.Add(new ILExpression(ILCode.YieldReturn, null, expr.Arguments[1]));
}
else
{
newBody.Add(body[pos]);
}
}
else if (returnVariable != null && expr != null && expr.Code == ILCode.Stloc && expr.Operand == returnVariable)
{
// handle store+branch to the returnVariable
ILExpression br = body.ElementAtOrDefault(++pos) as ILExpression;
if (br == null || !(br.Code == ILCode.Br || br.Code == ILCode.Leave) || br.Operand != returnLabel || expr.Arguments[0].Code != ILCode.Ldc_I4)
{
throw new YieldAnalysisFailedException();
}
int val = (int)expr.Arguments[0].Operand;
if (val == 0)
{
newBody.Add(MakeGoTo(returnFalseLabel));
}
else if (val == 1)
{
newBody.Add(MakeGoTo(labels, currentState));
}
else
{
throw new YieldAnalysisFailedException();
}
}
else if (expr != null && expr.Code == ILCode.Ret)
{
if (expr.Arguments.Count != 1 || expr.Arguments[0].Code != ILCode.Ldc_I4)
{
throw new YieldAnalysisFailedException();
}
// handle direct return (e.g. in release builds)
int val = (int)expr.Arguments[0].Operand;
if (val == 0)
{
newBody.Add(MakeGoTo(returnFalseLabel));
}
else if (val == 1)
{
newBody.Add(MakeGoTo(labels, currentState));
}
else
{
throw new YieldAnalysisFailedException();
}
}
else if (expr != null && expr.Code == ILCode.Call && expr.Arguments.Count == 1 && expr.Arguments[0].MatchThis())
{
MethodDefinition method = GetMethodDefinition(expr.Operand as MethodReference);
if (method == null)
{
throw new YieldAnalysisFailedException();
}
Interval interval;
if (method == disposeMethod)
{
// Explicit call to dispose is used for "yield break;" within the method.
ILExpression br = body.ElementAtOrDefault(++pos) as ILExpression;
if (br == null || !(br.Code == ILCode.Br || br.Code == ILCode.Leave) || br.Operand != returnFalseLabel)
{
throw new YieldAnalysisFailedException();
}
newBody.Add(MakeGoTo(returnFalseLabel));
}
else if (finallyMethodToStateInterval.TryGetValue(method, out interval))
{
// Call to Finally-method
int index = stateChanges.FindIndex(ss => ss.NewState >= interval.Start && ss.NewState <= interval.End);
if (index < 0)
{
throw new YieldAnalysisFailedException();
}
ILLabel label = new ILLabel();
label.Name = "JumpOutOfTryFinally" + interval.Start + "_" + interval.End;
newBody.Add(new ILExpression(ILCode.Leave, label));
SetState stateChange = stateChanges[index];
// Move all instructions from stateChange.Pos to newBody.Count into a try-block
stateChanges.RemoveRange(index, stateChanges.Count - index); // remove all state changes up to the one we found
ILTryCatchBlock tryFinally = new ILTryCatchBlock();
tryFinally.TryBlock = new ILBlock(newBody.GetRange(stateChange.NewBodyPos, newBody.Count - stateChange.NewBodyPos));
newBody.RemoveRange(stateChange.NewBodyPos, newBody.Count - stateChange.NewBodyPos); // remove all nodes that we just moved into the try block
tryFinally.CatchBlocks = new List <ILTryCatchBlock.CatchBlock>();
tryFinally.FinallyBlock = ConvertFinallyBlock(method);
newBody.Add(tryFinally);
newBody.Add(label);
}
}
else
{
newBody.Add(body[pos]);
}
}
newBody.Add(new ILExpression(ILCode.YieldBreak, null));
}
int AssignStateRanges(List <ILNode> body, int bodyLength, bool forDispose)
{
if (bodyLength == 0)
{
return(0);
}
for (int i = 0; i < bodyLength; i++)
{
StateRange nodeRange = ranges[body[i]];
nodeRange.Simplify();
ILLabel label = body[i] as ILLabel;
if (label != null)
{
ranges[body[i + 1]].UnionWith(nodeRange);
continue;
}
ILTryCatchBlock tryFinally = body[i] as ILTryCatchBlock;
if (tryFinally != null)
{
if (!forDispose || tryFinally.CatchBlocks.Count != 0 || tryFinally.FaultBlock != null || tryFinally.FinallyBlock == null)
{
throw new YieldAnalysisFailedException();
}
ranges[tryFinally.TryBlock].UnionWith(nodeRange);
if (tryFinally.TryBlock.Body.Count != 0)
{
ranges[tryFinally.TryBlock.Body[0]].UnionWith(nodeRange);
AssignStateRanges(tryFinally.TryBlock.Body, tryFinally.TryBlock.Body.Count, forDispose);
}
continue;
}
ILExpression expr = body[i] as ILExpression;
if (expr == null)
{
throw new YieldAnalysisFailedException();
}
switch (expr.Code)
{
case ILCode.Switch:
{
SymbolicValue val = Eval(expr.Arguments[0]);
if (val.Type != SymbolicValueType.State)
{
throw new YieldAnalysisFailedException();
}
ILLabel[] targetLabels = (ILLabel[])expr.Operand;
for (int j = 0; j < targetLabels.Length; j++)
{
int state = j - val.Constant;
ranges[targetLabels[j]].UnionWith(nodeRange, state, state);
}
StateRange nextRange = ranges[body[i + 1]];
nextRange.UnionWith(nodeRange, int.MinValue, -1 - val.Constant);
nextRange.UnionWith(nodeRange, targetLabels.Length - val.Constant, int.MaxValue);
break;
}
case ILCode.Br:
case ILCode.Leave:
ranges[(ILLabel)expr.Operand].UnionWith(nodeRange);
break;
case ILCode.Brtrue:
{
SymbolicValue val = Eval(expr.Arguments[0]);
if (val.Type == SymbolicValueType.StateEquals)
{
ranges[(ILLabel)expr.Operand].UnionWith(nodeRange, val.Constant, val.Constant);
StateRange nextRange = ranges[body[i + 1]];
nextRange.UnionWith(nodeRange, int.MinValue, val.Constant - 1);
nextRange.UnionWith(nodeRange, val.Constant + 1, int.MaxValue);
}
else if (val.Type == SymbolicValueType.StateInEquals)
{
ranges[body[i + 1]].UnionWith(nodeRange, val.Constant, val.Constant);
StateRange targetRange = ranges[(ILLabel)expr.Operand];
targetRange.UnionWith(nodeRange, int.MinValue, val.Constant - 1);
targetRange.UnionWith(nodeRange, val.Constant + 1, int.MaxValue);
}
else
{
throw new YieldAnalysisFailedException();
}
break;
}
case ILCode.Nop:
ranges[body[i + 1]].UnionWith(nodeRange);
break;
case ILCode.Ret:
break;
case ILCode.Stloc:
{
SymbolicValue val = Eval(expr.Arguments[0]);
if (val.Type == SymbolicValueType.State && val.Constant == 0 && rangeAnalysisStateVariable == null)
{
rangeAnalysisStateVariable = (ILVariable)expr.Operand;
}
else
{
throw new YieldAnalysisFailedException();
}
goto case ILCode.Nop;
}
case ILCode.Call:
// in some cases (e.g. foreach over array) the C# compiler produces a finally method outside of try-finally blocks
if (forDispose)
{
MethodDefinition mdef = GetMethodDefinition(expr.Operand as MethodReference);
if (mdef == null || finallyMethodToStateInterval.ContainsKey(mdef))
{
throw new YieldAnalysisFailedException();
}
finallyMethodToStateInterval.Add(mdef, nodeRange.ToEnclosingInterval());
}
else
{
throw new YieldAnalysisFailedException();
}
break;
default:
if (forDispose)
{
throw new YieldAnalysisFailedException();
}
else
{
return(i);
}
}
}
return(bodyLength);
}
void AnalyzeMoveNext()
{
MethodDefinition moveNextMethod = enumeratorType.Methods.FirstOrDefault(m => m.Name == "MoveNext");
ILBlock ilMethod = CreateILAst(moveNextMethod);
if (ilMethod.Body.Count == 0)
{
throw new SymbolicAnalysisFailedException();
}
ILExpression lastReturnArg;
if (!ilMethod.Body.Last().Match(ILCode.Ret, out lastReturnArg))
{
throw new SymbolicAnalysisFailedException();
}
// There are two possibilities:
if (lastReturnArg.Code == ILCode.Ldloc)
{
// a) the compiler uses a variable for returns (in debug builds, or when there are try-finally blocks)
returnVariable = (ILVariable)lastReturnArg.Operand;
returnLabel = ilMethod.Body.ElementAtOrDefault(ilMethod.Body.Count - 2) as ILLabel;
if (returnLabel == null)
{
throw new SymbolicAnalysisFailedException();
}
}
else
{
// b) the compiler directly returns constants
returnVariable = null;
returnLabel = null;
// In this case, the last return must return false.
if (lastReturnArg.Code != ILCode.Ldc_I4 || (int)lastReturnArg.Operand != 0)
{
throw new SymbolicAnalysisFailedException();
}
}
ILTryCatchBlock tryFaultBlock = ilMethod.Body[0] as ILTryCatchBlock;
List <ILNode> body;
int bodyLength;
if (tryFaultBlock != null)
{
// there are try-finally blocks
if (returnVariable == null) // in this case, we must use a return variable
{
throw new SymbolicAnalysisFailedException();
}
// must be a try-fault block:
if (tryFaultBlock.CatchBlocks.Count != 0 || tryFaultBlock.FinallyBlock != null || tryFaultBlock.FaultBlock == null)
{
throw new SymbolicAnalysisFailedException();
}
ILBlock faultBlock = tryFaultBlock.FaultBlock;
// Ensure the fault block contains the call to Dispose().
if (faultBlock.Body.Count != 2)
{
throw new SymbolicAnalysisFailedException();
}
MethodReference disposeMethodRef;
ILExpression disposeArg;
if (!faultBlock.Body[0].Match(ILCode.Call, out disposeMethodRef, out disposeArg))
{
throw new SymbolicAnalysisFailedException();
}
if (GetMethodDefinition(disposeMethodRef) != disposeMethod || !disposeArg.MatchThis())
{
throw new SymbolicAnalysisFailedException();
}
if (!faultBlock.Body[1].Match(ILCode.Endfinally))
{
throw new SymbolicAnalysisFailedException();
}
body = tryFaultBlock.TryBlock.Body;
bodyLength = body.Count;
}
else
{
// no try-finally blocks
body = ilMethod.Body;
if (returnVariable == null)
{
bodyLength = body.Count - 1; // all except for the return statement
}
else
{
bodyLength = body.Count - 2; // all except for the return label and statement
}
}
// Now verify that the last instruction in the body is 'ret(false)'
if (returnVariable != null)
{
// If we don't have a return variable, we already verified that above.
// If we do have one, check for 'stloc(returnVariable, ldc.i4(0))'
// Maybe might be a jump to the return label after the stloc:
ILExpression leave = body.ElementAtOrDefault(bodyLength - 1) as ILExpression;
if (leave != null && (leave.Code == ILCode.Br || leave.Code == ILCode.Leave) && leave.Operand == returnLabel)
{
bodyLength--;
}
ILExpression store0 = body.ElementAtOrDefault(bodyLength - 1) as ILExpression;
if (store0 == null || store0.Code != ILCode.Stloc || store0.Operand != returnVariable)
{
throw new SymbolicAnalysisFailedException();
}
if (store0.Arguments[0].Code != ILCode.Ldc_I4 || (int)store0.Arguments[0].Operand != 0)
{
throw new SymbolicAnalysisFailedException();
}
bodyLength--; // don't conside the stloc instruction to be part of the body
}
// The last element in the body usually is a label pointing to the 'ret(false)'
returnFalseLabel = body.ElementAtOrDefault(bodyLength - 1) as ILLabel;
// Note: in Roslyn-compiled code, returnFalseLabel may be null.
var rangeAnalysis = new StateRangeAnalysis(body[0], StateRangeAnalysisMode.IteratorMoveNext, stateField);
int pos = rangeAnalysis.AssignStateRanges(body, bodyLength);
rangeAnalysis.EnsureLabelAtPos(body, ref pos, ref bodyLength);
var labels = rangeAnalysis.CreateLabelRangeMapping(body, pos, bodyLength);
ConvertBody(body, pos, bodyLength, labels);
}
List <ILNode> ConvertToAst(List <ByteCode> body, HashSet <ExceptionHandler> ehs)
{
List <ILNode> ast = new List <ILNode>();
while (ehs.Any())
{
ILTryCatchBlock tryCatchBlock = new ILTryCatchBlock();
// Find the first and widest scope
uint tryStart = ehs.Min(eh => eh.TryStart.GetOffset());
uint tryEnd = ehs.Where(eh => eh.TryStart.GetOffset() == tryStart).Max(eh => eh.TryEnd.GetOffset());
var handlers = ehs.Where(eh => eh.TryStart.GetOffset() == tryStart && eh.TryEnd.GetOffset() == tryEnd).ToList();
// Remember that any part of the body migt have been removed due to unreachability
// Cut all instructions up to the try block
{
int tryStartIdx = 0;
while (tryStartIdx < body.Count && body[tryStartIdx].Offset < tryStart)
{
tryStartIdx++;
}
ast.AddRange(ConvertToAst(body.CutRange(0, tryStartIdx)));
}
// Cut the try block
{
HashSet <ExceptionHandler> nestedEHs = new HashSet <ExceptionHandler>(ehs.Where(eh => (tryStart <= eh.TryStart.GetOffset() && eh.TryEnd.GetOffset() < tryEnd) || (tryStart < eh.TryStart.GetOffset() && eh.TryEnd.GetOffset() <= tryEnd)));
ehs.ExceptWith(nestedEHs);
int tryEndIdx = 0;
while (tryEndIdx < body.Count && body[tryEndIdx].Offset < tryEnd)
{
tryEndIdx++;
}
tryCatchBlock.TryBlock = new ILBlock(ConvertToAst(body.CutRange(0, tryEndIdx), nestedEHs));
}
// Cut all handlers
tryCatchBlock.CatchBlocks = new List <ILTryCatchBlock.CatchBlock>();
foreach (ExceptionHandler eh in handlers)
{
uint handlerEndOffset = eh.HandlerEnd == null ? (uint)methodDef.Body.GetCodeSize() : eh.HandlerEnd.Offset;
int startIdx = 0;
while (startIdx < body.Count && body[startIdx].Offset < eh.HandlerStart.GetOffset())
{
startIdx++;
}
int endIdx = 0;
while (endIdx < body.Count && body[endIdx].Offset < handlerEndOffset)
{
endIdx++;
}
HashSet <ExceptionHandler> nestedEHs = new HashSet <ExceptionHandler>(ehs.Where(e => (eh.HandlerStart.GetOffset() <= e.TryStart.GetOffset() && e.TryEnd.GetOffset() < handlerEndOffset) || (eh.HandlerStart.GetOffset() < e.TryStart.GetOffset() && e.TryEnd.GetOffset() <= handlerEndOffset)));
ehs.ExceptWith(nestedEHs);
List <ILNode> handlerAst = ConvertToAst(body.CutRange(startIdx, endIdx - startIdx), nestedEHs);
if (eh.HandlerType == ExceptionHandlerType.Catch)
{
ILTryCatchBlock.CatchBlock catchBlock = new ILTryCatchBlock.CatchBlock(handlerAst)
{
ExceptionType = eh.CatchType.ToTypeSig(),
};
// Handle the automatically pushed exception on the stack
ByteCode ldexception = ldexceptions[eh];
ConvertExceptionVariable(eh, catchBlock, ldexception);
tryCatchBlock.CatchBlocks.Add(catchBlock);
}
else if (eh.HandlerType == ExceptionHandlerType.Finally)
{
tryCatchBlock.FinallyBlock = new ILBlock(handlerAst);
}
else if (eh.HandlerType == ExceptionHandlerType.Fault)
{
tryCatchBlock.FaultBlock = new ILBlock(handlerAst);
}
else if (useNewFilterCode && eh.HandlerType == ExceptionHandlerType.Filter)
{
ILTryCatchBlock.CatchBlock catchBlock = new ILTryCatchBlock.CatchBlock(handlerAst)
{
ExceptionType = eh.CatchType.ToTypeSig(),
};
// Handle the automatically pushed exception on the stack
ByteCode ldexception = ldexceptions[eh];
ConvertExceptionVariable(eh, catchBlock, ldexception);
// Extract the filter part
startIdx = 0;
while (startIdx < body.Count && body[startIdx].Offset < eh.FilterStart.GetOffset())
{
startIdx++;
}
endIdx = 0;
while (endIdx < body.Count && body[endIdx].Offset < eh.HandlerStart.GetOffset())
{
endIdx++;
}
nestedEHs = new HashSet <ExceptionHandler>(ehs.Where(e => (eh.FilterStart.GetOffset() <= e.TryStart.GetOffset() && e.TryEnd.GetOffset() < eh.HandlerStart.GetOffset()) || (eh.FilterStart.GetOffset() < e.TryStart.GetOffset() && e.TryEnd.GetOffset() <= eh.HandlerStart.GetOffset())));
ehs.ExceptWith(nestedEHs);
List <ILNode> filterAst = ConvertToAst(body.CutRange(startIdx, endIdx - startIdx), nestedEHs);
var filterBlock = new ILTryCatchBlock.FilterILBlock()
{
Body = filterAst
};
ByteCode ldfilter = ldfilters[eh];
ConvertExceptionVariable(eh, filterBlock, ldfilter);
filterBlock.HandlerBlock = catchBlock;
filterBlock.StlocILRanges.AddRange(catchBlock.StlocILRanges);
tryCatchBlock.FilterBlock = filterBlock;
}
else
{
}
}
ehs.ExceptWith(handlers);
ast.Add(tryCatchBlock);
}
// Add whatever is left
ast.AddRange(ConvertToAst(body));
return(ast);
}
List <ILNode> ConvertToAst(List <ByteCode> body, HashSet <ExceptionHandler> ehs)
{
List <ILNode> ast = new List <ILNode>();
while (ehs.Any())
{
ILTryCatchBlock tryCatchBlock = new ILTryCatchBlock();
// Find the first and widest scope
int tryStart = ehs.Min(eh => eh.TryStart.Offset);
int tryEnd = ehs.Where(eh => eh.TryStart.Offset == tryStart).Max(eh => eh.TryEnd.Offset);
var handlers = ehs.Where(eh => eh.TryStart.Offset == tryStart && eh.TryEnd.Offset == tryEnd).ToList();
// Cut all instructions up to the try block
{
int tryStartIdx;
for (tryStartIdx = 0; body[tryStartIdx].Offset != tryStart; tryStartIdx++)
{
;
}
ast.AddRange(ConvertToAst(body.CutRange(0, tryStartIdx)));
}
// Cut the try block
{
HashSet <ExceptionHandler> nestedEHs = new HashSet <ExceptionHandler>(ehs.Where(eh => (tryStart <= eh.TryStart.Offset && eh.TryEnd.Offset < tryEnd) || (tryStart < eh.TryStart.Offset && eh.TryEnd.Offset <= tryEnd)));
ehs.ExceptWith(nestedEHs);
int tryEndIdx;
for (tryEndIdx = 0; tryEndIdx < body.Count && body[tryEndIdx].Offset != tryEnd; tryEndIdx++)
{
;
}
tryCatchBlock.TryBlock = new ILBlock(ConvertToAst(body.CutRange(0, tryEndIdx), nestedEHs));
}
// Cut all handlers
tryCatchBlock.CatchBlocks = new List <ILTryCatchBlock.CatchBlock>();
foreach (ExceptionHandler eh in handlers)
{
int startIndex;
for (startIndex = 0; body[startIndex].Offset != eh.HandlerStart.Offset; startIndex++)
{
;
}
int endInclusiveIndex;
if (eh.HandlerEnd == null)
{
endInclusiveIndex = body.Count - 1;
}
// Note that the end(exclusive) instruction may not necessarly be in our body
else
{
for (endInclusiveIndex = 0; body[endInclusiveIndex].Next.Offset != eh.HandlerEnd.Offset; endInclusiveIndex++)
{
;
}
}
int count = 1 + endInclusiveIndex - startIndex;
HashSet <ExceptionHandler> nestedEHs = new HashSet <ExceptionHandler>(ehs.Where(e => (eh.HandlerStart.Offset <= e.TryStart.Offset && e.TryEnd.Offset < eh.HandlerEnd.Offset) || (eh.HandlerStart.Offset < e.TryStart.Offset && e.TryEnd.Offset <= eh.HandlerEnd.Offset)));
ehs.ExceptWith(nestedEHs);
List <ILNode> handlerAst = ConvertToAst(body.CutRange(startIndex, count), nestedEHs);
if (eh.HandlerType == ExceptionHandlerType.Catch)
{
ILTryCatchBlock.CatchBlock catchBlock = new ILTryCatchBlock.CatchBlock()
{
ExceptionType = eh.CatchType,
Body = handlerAst
};
// Handle the automatically pushed exception on the stack
ByteCode ldexception = ldexceptions[eh];
if (ldexception.StoreTo.Count == 0)
{
throw new Exception("Exception should be consumed by something");
}
else if (ldexception.StoreTo.Count == 1)
{
ILExpression first = catchBlock.Body[0] as ILExpression;
if (first != null &&
first.Code == ILCode.Pop &&
first.Arguments[0].Code == ILCode.Ldloc &&
first.Arguments[0].Operand == ldexception.StoreTo[0])
{
// The exception is just poped - optimize it all away;
catchBlock.ExceptionVariable = null;
catchBlock.Body.RemoveAt(0);
}
else
{
catchBlock.ExceptionVariable = ldexception.StoreTo[0];
}
}
else
{
ILVariable exTemp = new ILVariable()
{
Name = "ex_" + eh.HandlerStart.Offset.ToString("X2"), IsGenerated = true
};
catchBlock.ExceptionVariable = exTemp;
foreach (ILVariable storeTo in ldexception.StoreTo)
{
catchBlock.Body.Insert(0, new ILExpression(ILCode.Stloc, storeTo, new ILExpression(ILCode.Ldloc, exTemp)));
}
}
tryCatchBlock.CatchBlocks.Add(catchBlock);
}
else if (eh.HandlerType == ExceptionHandlerType.Finally)
{
tryCatchBlock.FinallyBlock = new ILBlock(handlerAst);
}
else if (eh.HandlerType == ExceptionHandlerType.Fault)
{
tryCatchBlock.FaultBlock = new ILBlock(handlerAst);
}
else
{
// TODO: ExceptionHandlerType.Filter
}
}
ehs.ExceptWith(handlers);
ast.Add(tryCatchBlock);
}
// Add whatever is left
ast.AddRange(ConvertToAst(body));
return(ast);
}
void AnalyzeMoveNext()
{
ILBlock ilMethod = CreateILAst(moveNextMethod);
int startIndex;
if (ilMethod.Body.Count == 6)
{
startIndex = 0;
}
else if (ilMethod.Body.Count == 7)
{
// stloc(cachedState, ldfld(valuetype StateMachineStruct::<>1__state, ldloc(this)))
ILExpression cachedStateInit;
if (!ilMethod.Body[0].Match(ILCode.Stloc, out cachedStateVar, out cachedStateInit))
{
throw new SymbolicAnalysisFailedException();
}
ILExpression instanceExpr;
FieldReference loadedField;
if (!cachedStateInit.Match(ILCode.Ldfld, out loadedField, out instanceExpr) || loadedField.ResolveWithinSameModule() != stateField || !instanceExpr.MatchThis())
{
throw new SymbolicAnalysisFailedException();
}
startIndex = 1;
}
else
{
throw new SymbolicAnalysisFailedException();
}
mainTryCatch = ilMethod.Body[startIndex + 0] as ILTryCatchBlock;
if (mainTryCatch == null || mainTryCatch.CatchBlocks.Count != 1)
{
throw new SymbolicAnalysisFailedException();
}
if (mainTryCatch.FaultBlock != null || mainTryCatch.FinallyBlock != null)
{
throw new SymbolicAnalysisFailedException();
}
setResultAndExitLabel = ilMethod.Body[startIndex + 1] as ILLabel;
if (setResultAndExitLabel == null)
{
throw new SymbolicAnalysisFailedException();
}
if (!MatchStateAssignment(ilMethod.Body[startIndex + 2], out finalState))
{
throw new SymbolicAnalysisFailedException();
}
// call(AsyncTaskMethodBuilder`1::SetResult, ldflda(StateMachine::<>t__builder, ldloc(this)), ldloc(<>t__result))
MethodReference setResultMethod;
ILExpression builderExpr;
if (methodType == AsyncMethodType.TaskOfT)
{
if (!ilMethod.Body[startIndex + 3].Match(ILCode.Call, out setResultMethod, out builderExpr, out resultExpr))
{
throw new SymbolicAnalysisFailedException();
}
}
else
{
if (!ilMethod.Body[startIndex + 3].Match(ILCode.Call, out setResultMethod, out builderExpr))
{
throw new SymbolicAnalysisFailedException();
}
}
if (!(setResultMethod.Name == "SetResult" && IsBuilderFieldOnThis(builderExpr)))
{
throw new SymbolicAnalysisFailedException();
}
exitLabel = ilMethod.Body[startIndex + 4] as ILLabel;
if (exitLabel == null)
{
throw new SymbolicAnalysisFailedException();
}
}
/// <summary>
/// Get the first expression to be excecuted if the instruction pointer is at the start of the given node.
/// Try blocks may not be entered in any way. If possible, the try block is returned as the node to be executed.
/// </summary>
ILNode Enter(ILNode node, HashSet <ILNode> visitedNodes)
{
if (node == null)
{
throw new ArgumentNullException();
}
if (!visitedNodes.Add(node))
{
return(null); // Infinite loop
}
ILLabel label = node as ILLabel;
if (label != null)
{
return(Exit(label, visitedNodes));
}
ILExpression expr = node as ILExpression;
if (expr != null)
{
if (expr.Code == ILCode.Br || expr.Code == ILCode.Leave)
{
ILLabel target = (ILLabel)expr.Operand;
// Early exit - same try-block
if (GetParents(expr).OfType <ILTryCatchBlock>().FirstOrDefault() == GetParents(target).OfType <ILTryCatchBlock>().FirstOrDefault())
{
return(Enter(target, visitedNodes));
}
// Make sure we are not entering any try-block
var srcTryBlocks = GetParents(expr).OfType <ILTryCatchBlock>().Reverse().ToList();
var dstTryBlocks = GetParents(target).OfType <ILTryCatchBlock>().Reverse().ToList();
// Skip blocks that we are already in
int i = 0;
while (i < srcTryBlocks.Count && i < dstTryBlocks.Count && srcTryBlocks[i] == dstTryBlocks[i])
{
i++;
}
if (i == dstTryBlocks.Count)
{
return(Enter(target, visitedNodes));
}
else
{
ILTryCatchBlock dstTryBlock = dstTryBlocks[i];
// Check that the goto points to the start
ILTryCatchBlock current = dstTryBlock;
while (current != null)
{
foreach (ILNode n in current.TryBlock.Body)
{
if (n is ILLabel)
{
if (n == target)
{
return(dstTryBlock);
}
}
else if (!n.Match(ILCode.Nop))
{
current = n as ILTryCatchBlock;
break;
}
}
}
return(null);
}
}
else if (expr.Code == ILCode.Nop)
{
return(Exit(expr, visitedNodes));
}
else if (expr.Code == ILCode.LoopOrSwitchBreak)
{
ILNode breakBlock = GetParents(expr).First(n => n is ILWhileLoop || n is ILSwitch);
return(Exit(breakBlock, new HashSet <ILNode>()
{
expr
}));
}
else if (expr.Code == ILCode.LoopContinue)
{
ILNode continueBlock = GetParents(expr).First(n => n is ILWhileLoop);
return(Enter(continueBlock, new HashSet <ILNode>()
{
expr
}));
}
else
{
return(expr);
}
}
ILBlock block = node as ILBlock;
if (block != null)
{
if (block.EntryGoto != null)
{
return(Enter(block.EntryGoto, visitedNodes));
}
else if (block.Body.Count > 0)
{
return(Enter(block.Body[0], visitedNodes));
}
else
{
return(Exit(block, visitedNodes));
}
}
ILCondition cond = node as ILCondition;
if (cond != null)
{
return(cond.Condition);
}
ILWhileLoop loop = node as ILWhileLoop;
if (loop != null)
{
if (loop.Condition != null)
{
return(loop.Condition);
}
else
{
return(Enter(loop.BodyBlock, visitedNodes));
}
}
ILTryCatchBlock tryCatch = node as ILTryCatchBlock;
if (tryCatch != null)
{
return(tryCatch);
}
ILSwitch ilSwitch = node as ILSwitch;
if (ilSwitch != null)
{
return(ilSwitch.Condition);
}
throw new NotSupportedException(node.GetType().ToString());
}