/// <summary>
/// Checks whether the specified block is a state controller block generated by the C# compiler in debug mode.
/// </summary>
/// <remarks>
/// Pattern:
/// ldc.i4.1
/// stloc* doFinallyVariable
/// ldarg.0
/// ldfld stateField
/// ...
/// ldc.i4.s -3
/// (sub) - missing if next is beq*
/// switch || beq*
///
/// There is only one such block generated at the begining of the MoveNext method.
/// </remarks>
/// <param name="theBlock"></param>
/// <returns></returns>
private bool IsDebugCheckStateBlock(InstructionBlock theBlock)
{
if (!BeginsWithDoFinallySet(theBlock) || !ContainsStateFieldLoad(theBlock))
{
return(false);
}
Instruction currentInstruction = theBlock.Last;
if (!this.IsBeqInstruction(currentInstruction))
{
if (currentInstruction.OpCode.Code != Code.Switch)
{
return(false);
}
currentInstruction = currentInstruction.Previous;
if (currentInstruction.OpCode.Code != Code.Sub)
{
return(false);
}
}
currentInstruction = currentInstruction.Previous;
int operand;
if (!StateMachineUtilities.TryGetOperandOfLdc(currentInstruction, out operand) || operand > -3)
{
return(false);
}
debugStateCheckBlock = theBlock;
stateCheckOffset = -operand;
return(true);
}
/// <summary>
/// Marks the predecessors of this block as yield return. Also adds this block to the set of nodes that are to be removed.
/// </summary>
/// <remarks>
/// If a predecessor of the specified block is a block with a single unconditional branch instruction, then this method is
/// recursively called for that predecessor.
/// </remarks>
/// <param name="theBlock"></param>
private bool MarkPredecessorsAsYieldReturns(InstructionBlock theBlock)
{
toBeRemoved.Add(theBlock);
HashSet <InstructionBlock> predecessors = new HashSet <InstructionBlock>(theBlock.Predecessors);
foreach (InstructionBlock predecessor in predecessors)
{
if (predecessor.Last == predecessor.First)
{
if (StateMachineUtilities.IsUnconditionalBranch(predecessor.Last) && MarkPredecessorsAsYieldReturns(predecessor))
{
continue;
}
else
{
//throw new Exception("Illegal block");
return(false);
}
}
if (!TryAddToYieldReturningBlocks(predecessor))
{
return(false);
}
}
return(true);
}
protected override bool IsFinallyCheckBlock(InstructionBlock finallyEntry)
{
Instruction current = finallyEntry.First;
VariableReference loadedVariable;
if (!StateMachineUtilities.TryGetVariableFromInstruction(current, methodVariables, out loadedVariable) ||
loadedVariable != this.stateVariable)
{
return(false);
}
current = current.Next;
if (current.OpCode.Code != Code.Ldc_I4_0)
{
return(false);
}
current = current.Next;
if (current.OpCode.Code != Code.Bge && current.OpCode.Code != Code.Bge_S)
{
return(false);
}
return(true);
}
private void GetStateVariable()
{
Instruction current = theCFG.Blocks[0].First;
if (current.OpCode.Code != Code.Ldarg_0)
{
return;
}
current = current.Next;
if (current.OpCode.Code != Code.Ldfld)
{
return;
}
FieldReference loadedField = current.Operand as FieldReference;
if (loadedField == null || loadedField.Resolve() != this.stateField)
{
return;
}
current = current.Next;
StateMachineUtilities.TryGetVariableFromInstruction(current, methodVariables, out stateVariable);
}
protected override bool IsFinallyCheckBlock(InstructionBlock theBlock)
{
V_0 = theBlock.get_First();
while (V_0.get_OpCode().get_Code() == null)
{
if ((object)V_0 == (object)theBlock.get_Last())
{
return(false);
}
V_0 = V_0.get_Next();
}
if ((object)V_0 == (object)theBlock.get_Last() || !StateMachineUtilities.TryGetVariableFromInstruction(V_0, this.methodVariables, out V_1) || (object)V_1 != (object)this.doFinallyVariable)
{
return(false);
}
V_0 = V_0.get_Next();
if (V_0.get_OpCode().get_Code() == 56 || V_0.get_OpCode().get_Code() == 43)
{
return(true);
}
if (this.IsCSharpDebugCheck(theBlock, V_0))
{
return(true);
}
return(this.IsVisualBasicDebugCheck(theBlock, V_0));
}
/// <summary>
/// Checks whether <paramref name="theBlock"/> is a do-finally-check block.
/// </summary>
/// <remarks>
/// Pattern:
/// (nop) - sequence of nop blocks
/// ldloc* doFinallyVariable
/// brfalse* - branch to endfinally - this check varies between compilers
/// original handler:
/// ...............
/// </remarks>
/// <param name="theBlock"></param>
/// <returns></returns>
protected override bool IsFinallyCheckBlock(InstructionBlock theBlock)
{
Instruction currentInstruction = theBlock.First;
while (currentInstruction.OpCode.Code == Code.Nop)
{
if (currentInstruction == theBlock.Last)
{
return(false);
}
currentInstruction = currentInstruction.Next;
}
VariableReference loadedVariable;
if (currentInstruction == theBlock.Last ||
!StateMachineUtilities.TryGetVariableFromInstruction(currentInstruction, methodVariables, out loadedVariable) ||
loadedVariable != doFinallyVariable)
{
return(false);
}
currentInstruction = currentInstruction.Next;
if (currentInstruction.OpCode.Code == Code.Brfalse || currentInstruction.OpCode.Code == Code.Brfalse_S)
{
return(true);
}
return(IsCSharpDebugCheck(theBlock, currentInstruction) || IsVisualBasicDebugCheck(theBlock, currentInstruction));
}
/// <summary>
/// Tries to get the state to which the current block leads.
/// </summary>
/// <remarks>
/// We are searching for this pattern at the end of the block:
/// .....
/// load currentItemValue
/// stfld currentItemField
/// ldarg.0 --this
/// ldc.i4. nextStateNumber
/// stfld stateField
/// .....
/// </remarks>
/// <param name="theBlock"></param>
/// <param name="newStateNumber"></param>
/// <returns></returns>
private NextStateNumberSearchResult TryGetNextStateNumber(InstructionBlock theBlock, out int newStateNumber)
{
Instruction currentInstruction = theBlock.Last;
while (currentInstruction != theBlock.First)
{
if (currentInstruction.OpCode.Code == Code.Stfld && stateField == ((FieldReference)currentInstruction.Operand).Resolve())
{
currentInstruction = currentInstruction.Previous;
if (!StateMachineUtilities.TryGetOperandOfLdc(currentInstruction, out newStateNumber))
{
return(NextStateNumberSearchResult.PatternFailed);
}
//currentInstruction == ldc.i4. ; currentInstruction.Previous == ldarg.0 ; currentInstruction.Previous.Previous == stfld currentItemField
currentInstruction = currentInstruction.Previous.Previous;
if (currentInstruction.OpCode.Code != Code.Stfld || !CheckAndSaveCurrentItemField((FieldReference)currentInstruction.Operand))
{
return(NextStateNumberSearchResult.PatternFailed);
}
return(NextStateNumberSearchResult.StateNumberFound);
}
currentInstruction = currentInstruction.Previous;
}
newStateNumber = 0;
return(NextStateNumberSearchResult.StateWasNotSet);
}
private bool DetermineExceptionHandlingStatesFromSwitchData(SwitchData switchBlockInfo)
{
V_0 = 0;
V_1 = switchBlockInfo.get_SwitchBlock().get_Last().get_Previous();
if (V_1.get_OpCode().get_Code() == 88)
{
V_1 = V_1.get_Previous();
if (!StateMachineUtilities.TryGetOperandOfLdc(V_1, out V_0))
{
return(false);
}
V_1 = V_1.get_Previous();
}
V_2 = switchBlockInfo.get_OrderedCasesArray();
V_4 = 0;
while (V_4 < (int)V_2.Length)
{
if (this.TryGetExceptionHandler(this.GetActualCase(V_2[V_4]), out V_6))
{
if (!this.handlerToStatesMap.ContainsKey(V_6))
{
this.handlerToStatesMap.Add(V_6, new HashSet <int>());
}
dummyVar0 = this.handlerToStatesMap.get_Item(V_6).Add(V_4 + V_0);
}
V_4 = V_4 + 1;
}
return(true);
}
private bool IsDebugCheckStateBlock(InstructionBlock theBlock)
{
if (!this.BeginsWithDoFinallySet(theBlock) || !this.ContainsStateFieldLoad(theBlock))
{
return(false);
}
V_0 = theBlock.get_Last();
if (!this.IsBeqInstruction(V_0))
{
if (V_0.get_OpCode().get_Code() != 68)
{
return(false);
}
V_0 = V_0.get_Previous();
if (V_0.get_OpCode().get_Code() != 88)
{
return(false);
}
}
V_0 = V_0.get_Previous();
if (!StateMachineUtilities.TryGetOperandOfLdc(V_0, out V_1) || V_1 > -3)
{
return(false);
}
this.debugStateCheckBlock = theBlock;
this.stateCheckOffset = -V_1;
return(true);
}
private bool GetDoFinallyVariable()
{
V_0 = this.theCFG.get_Blocks()[0].get_First();
if (V_0.get_OpCode().get_Code() != 23)
{
return(false);
}
return(StateMachineUtilities.TryGetVariableFromInstruction(V_0.get_Next(), this.methodVariables, out this.doFinallyVariable));
}
/// <summary>
/// Marks the predecessors, of the specifed instruction block, that set the return flag variable to true, as yield returns.
/// </summary>
/// <remarks>
/// If a predecessor is a block that contains a single unconditional branch instruction then we recursively call the method for that
/// predecessor and we mark it for removal.
/// This means that the block, that we initially call this method for, will not be removed and will be left to be marked as an yield break.
/// </remarks>
/// <param name="theBlock"></param>
private bool MarkTrueReturningPredecessorsAsYieldReturn(InstructionBlock theBlock)
{
HashSet <InstructionBlock> predecessors = new HashSet <InstructionBlock>(theBlock.Predecessors);
foreach (InstructionBlock predecessor in predecessors)
{
if (predecessor.Last == predecessor.First)
{
if (StateMachineUtilities.IsUnconditionalBranch(predecessor.Last))
{
toBeRemoved.Add(predecessor);
if (!MarkTrueReturningPredecessorsAsYieldReturn(predecessor))
{
return(false);
}
continue;
}
else
{
return(false);
}
}
VariableReference flagVarReference = null;
Instruction lastInstruction = predecessor.Last;
if (StateMachineUtilities.IsUnconditionalBranch(lastInstruction))
{
lastInstruction = lastInstruction.Previous;
}
int returnValue;
if (TryGetVariableFromInstruction(lastInstruction, out flagVarReference) && CheckAndSaveReturnFlagVariable(flagVarReference) &&
StateMachineUtilities.TryGetOperandOfLdc(lastInstruction.Previous, out returnValue))
{
if (returnValue == 1)
{
if (!TryAddToYieldReturningBlocks(predecessor))
{
return(false);
}
}
else if (returnValue != 0)
{
return(false);
}
}
else
{
return(false);
}
}
return(true);
}
/// <summary>
/// Gets the doFinallyBodies variable from the first block of the MoveNext method.
/// </summary>
/// <returns>True on success, otherwise false.</returns>
private bool GetDoFinallyVariable()
{
Instruction entry = theCFG.Blocks[0].First;
if (entry.OpCode.Code != Code.Ldc_I4_1)
{
return(false);
}
return(StateMachineUtilities.TryGetVariableFromInstruction(entry.Next, methodVariables, out doFinallyVariable));
}
private void GetStateVariable()
{
V_0 = this.theCFG.get_Blocks()[0].get_First();
if (V_0.get_OpCode().get_Code() != 2)
{
return;
}
V_0 = V_0.get_Next();
if (V_0.get_OpCode().get_Code() != 120)
{
return;
}
V_1 = V_0.get_Operand() as FieldReference;
if (V_1 == null || (object)V_1.Resolve() != (object)this.stateField)
{
return;
}
V_0 = V_0.get_Next();
dummyVar0 = StateMachineUtilities.TryGetVariableFromInstruction(V_0, this.methodVariables, out this.stateVariable);
if ((object)V_0 == (object)this.theCFG.get_Blocks()[0].get_Last())
{
return;
}
V_0 = V_0.get_Next();
V_2 = true;
while (V_2)
{
if (V_0.get_OpCode().get_Code() == 2)
{
V_0 = V_0.get_Next();
if (V_0.get_OpCode().get_Code() == 120)
{
V_4 = V_0.get_Operand() as FieldReference;
if (V_4 != null)
{
V_0 = V_0.get_Next();
if (StateMachineUtilities.TryGetVariableFromInstruction(V_0, this.methodVariables, out V_5))
{
this.variableToFieldMap.Add(V_5, V_4);
if ((object)V_0 == (object)this.theCFG.get_Blocks()[0].get_Last())
{
break;
}
V_0 = V_0.get_Next();
continue;
}
}
}
}
V_2 = false;
}
return;
}
/// <summary>
/// Checks if the given block is block that contains only Finally method invocation. This pattern is brought by the new C#6.0 compiler.
/// </summary>
private bool IsFinallyMethodInvocationBlock(InstructionBlock block)
{
// The pattern is like so:
// ldarg.0
// call instance void ... (the finally method)
// nop <- could be missing
// leave.s ...
Instruction current = block.First;
if (current.OpCode.Code != Code.Ldarg_0)
{
return(false);
}
current = current.Next;
if (current.OpCode.Code != Code.Call)
{
return(false);
}
Instruction callInstruction = current;
current = current.Next;
if (current.OpCode.Code == Code.Nop)
{
current = current.Next;
}
if (!StateMachineUtilities.IsUnconditionalBranch(current))
{
return(false);
}
if (block.Last != current)
{
return(false);
}
MethodReference finallyMethod = callInstruction.Operand as MethodReference;
if (finallyMethod == null)
{
return(false);
}
if (!finallyMethod.Name.StartsWith("<>m__Finally"))
{
return(false);
}
return(true);
}
/// <summary>
/// Process the specified block, which ends with ret instruction.
/// </summary>
/// <remarks>
/// The block should end with: return true, return false or return flagVariable.
/// If the block ends with "return flagVariable", then we mark the block as yield break and we search for all of the predecessors of
/// the block that set the flagVariable to true to mark them as yield returns.
/// </remarks>
/// <param name="theBlock"></param>
private bool TryProcessEndBlock(InstructionBlock theBlock)
{
VariableReference flagVarReference = null;
Instruction beforeRet = theBlock.Last.Previous;
int returnValue;
if (StateMachineUtilities.TryGetOperandOfLdc(beforeRet, out returnValue))
{
if (returnValue == 0) // == return false;
{
yieldBreaks.Add(theBlock);
}
else if (returnValue == 1) // == return true;
{
int stateNumber;
switch (TryGetNextStateNumber(theBlock, out stateNumber))
{
case NextStateNumberSearchResult.StateNumberFound:
yieldReturns.Add(theBlock);
InstructionBlock nextState = GetStateFistBlock(stateNumber);
theBlock.Successors = new InstructionBlock[] { nextState };
break;
case NextStateNumberSearchResult.StateWasNotSet:
//If we cannot find the next state number, we assume that this is a common exit for a bunch of yield return blocks.
//That's why we mark all the predecessors of this block as yield returns.
return(MarkPredecessorsAsYieldReturns(theBlock));
case NextStateNumberSearchResult.PatternFailed:
return(false);
}
}
else
{
//throw new Exception("Illegal return value of MoveNext method.");
return(false);
}
}
else if (TryGetVariableFromInstruction(beforeRet, out flagVarReference) && CheckAndSaveReturnFlagVariable(flagVarReference))
{
yieldBreaks.Add(theBlock);
return(MarkTrueReturningPredecessorsAsYieldReturn(theBlock));
}
else
{
//throw new Exception("Illegal end block of yield iterator.");
return(false);
}
return(true);
}
private bool BeginsWithDoFinallySet(InstructionBlock theBlock)
{
V_0 = theBlock.get_First();
if ((object)V_0 == (object)theBlock.get_Last() || V_0.get_OpCode().get_Code() != 23)
{
return(false);
}
if (!StateMachineUtilities.TryGetVariableFromInstruction(V_0.get_Next(), this.methodContext.get_Body().get_Variables(), out V_1))
{
return(false);
}
return((object)V_1 == (object)this.doFinallyVariable);
}
/// <summary>
/// Checks whether the specified block begins with setting the doFinallyBodies variable to true.
/// </summary>
/// <param name="theBlock"></param>
/// <returns></returns>
private bool BeginsWithDoFinallySet(InstructionBlock theBlock)
{
Instruction currentInstruction = theBlock.First;
if (currentInstruction == theBlock.Last || currentInstruction.OpCode.Code != Code.Ldc_I4_1)
{
return(false);
}
VariableReference foundVariable;
return(StateMachineUtilities.TryGetVariableFromInstruction(currentInstruction.Next, methodContext.Body.Variables, out foundVariable) &&
foundVariable == doFinallyVariable);
}
private bool IsFalseReturnBlock(InstructionBlock theBlock)
{
V_0 = theBlock.get_First();
if (V_0.get_OpCode().get_Code() != 22 || (object)V_0 == (object)theBlock.get_Last())
{
return(false);
}
V_0 = V_0.get_Next();
if (!this.TryGetVariableFromInstruction(V_0, out V_1) || (object)V_0 == (object)theBlock.get_Last() || !this.CheckAndSaveReturnFlagVariable(V_1))
{
return(false);
}
V_0 = V_0.get_Next();
return(StateMachineUtilities.IsUnconditionalBranch(V_0));
}
private bool TryProcessEndBlock(InstructionBlock theBlock)
{
V_0 = null;
V_1 = theBlock.get_Last().get_Previous();
if (!StateMachineUtilities.TryGetOperandOfLdc(V_1, out V_2))
{
if (!this.TryGetVariableFromInstruction(V_1, out V_0) || !this.CheckAndSaveReturnFlagVariable(V_0))
{
return(false);
}
dummyVar2 = this.yieldBreaks.Add(theBlock);
return(this.MarkTrueReturningPredecessorsAsYieldReturn(theBlock));
}
if (V_2 != 0)
{
if (V_2 != 1)
{
return(false);
}
switch (this.TryGetNextStateNumber(theBlock, out V_3))
{
case 0:
{
return(false);
}
case 1:
{
dummyVar1 = this.yieldReturns.Add(theBlock);
V_4 = this.GetStateFistBlock(V_3);
stackVariable41 = new InstructionBlock[1];
stackVariable41[0] = V_4;
theBlock.set_Successors(stackVariable41);
break;
}
case 2:
{
return(this.MarkPredecessorsAsYieldReturns(theBlock));
}
}
}
else
{
dummyVar0 = this.yieldBreaks.Add(theBlock);
}
return(true);
}
/// <summary>
/// Process each CFG block to determine which cases lead to try/finally construct.
/// </summary>
private void DetermineExceptionHandlingStatesFromCFGBlocks()
{
foreach (InstructionBlock block in theDisposeCFG.Blocks)
{
int state;
if ((!IsBeqInstruction(block.Last) && !IsBneUnInstruction(block.Last)) ||
!StateMachineUtilities.TryGetOperandOfLdc(block.Last.Previous, out state))
{
continue;
}
Instruction branchTargetInstruction = null;
if (IsBeqInstruction(block.Last))
{
branchTargetInstruction = block.Last.Operand as Instruction;
}
else // bne.un*
{
branchTargetInstruction = block.Last.Next as Instruction;
}
if (branchTargetInstruction == null)
{
throw new Exception("branchTargetInstruction cannot be null.");
}
InstructionBlock targetBlock = SkipSingleNopInstructionBlock(theDisposeCFG.InstructionToBlockMapping[branchTargetInstruction.Offset]);
ExceptionHandler theHandler;
if (!TryGetExceptionHandler(targetBlock, out theHandler))
{
continue;
}
//We've found an exception handler.
if (!this.handlerToStatesMap.ContainsKey(theHandler))
{
this.handlerToStatesMap.Add(theHandler, new HashSet <int>());
}
this.handlerToStatesMap[theHandler].Add(state);
}
}
protected override bool IsFinallyCheckBlock(InstructionBlock finallyEntry)
{
V_0 = finallyEntry.get_First();
if (!StateMachineUtilities.TryGetVariableFromInstruction(V_0, this.methodVariables, out V_1) || (object)V_1 != (object)this.stateVariable)
{
return(false);
}
V_0 = V_0.get_Next();
if (V_0.get_OpCode().get_Code() != 22)
{
return(false);
}
V_0 = V_0.get_Next();
if (V_0.get_OpCode().get_Code() != 59 && V_0.get_OpCode().get_Code() != 46)
{
return(false);
}
return(true);
}
/// <summary>
/// Process each switch block to determine which cases lead to try/finally constructs.
/// </summary>
/// <param name="switchBlockInfo"></param>
private bool DetermineExceptionHandlingStatesFromSwitchData(SwitchData switchBlockInfo)
{
//Since the first try/finally that this switch covers can start at state 20, the complier will optimize this by subtracting 20 from the value of
//the state field.
int stateOffset = 0;
Instruction currentInstruction = switchBlockInfo.SwitchBlock.Last.Previous;
if (currentInstruction.OpCode.Code == Code.Sub)
{
currentInstruction = currentInstruction.Previous;
if (!StateMachineUtilities.TryGetOperandOfLdc(currentInstruction, out stateOffset))
{
return(false);
}
currentInstruction = currentInstruction.Previous;
}
InstructionBlock[] orderedCases = switchBlockInfo.OrderedCasesArray;
for (int i = 0; i < orderedCases.Length; i++)
{
InstructionBlock currentCase = GetActualCase(orderedCases[i]);
ExceptionHandler theHandler;
if (!TryGetExceptionHandler(currentCase, out theHandler))
{
continue;
}
//We've found an exception handler.
if (!this.handlerToStatesMap.ContainsKey(theHandler))
{
this.handlerToStatesMap.Add(theHandler, new HashSet <int>());
}
this.handlerToStatesMap[theHandler].Add(i + stateOffset);
}
return(true);
}
/// <summary>
/// Checks whether the block sets the returnFlag variable to false.
/// </summary>
/// <param name="theBlock"></param>
/// <returns></returns>
private bool IsFalseReturnBlock(InstructionBlock theBlock)
{
Instruction currentInstruction = theBlock.First;
if (currentInstruction.OpCode.Code != Code.Ldc_I4_0 || currentInstruction == theBlock.Last)
{
return(false);
}
currentInstruction = currentInstruction.Next;
VariableReference retFlagVariable;
if (!TryGetVariableFromInstruction(currentInstruction, out retFlagVariable) || currentInstruction == theBlock.Last ||
!CheckAndSaveReturnFlagVariable(retFlagVariable))
{
return(false);
}
currentInstruction = currentInstruction.Next;
return(StateMachineUtilities.IsUnconditionalBranch(currentInstruction));
}
private bool MarkPredecessorsAsYieldReturns(InstructionBlock theBlock)
{
dummyVar0 = this.toBeRemoved.Add(theBlock);
V_0 = (new HashSet <InstructionBlock>(theBlock.get_Predecessors())).GetEnumerator();
try
{
while (V_0.MoveNext())
{
V_1 = V_0.get_Current();
if ((object)V_1.get_Last() != (object)V_1.get_First())
{
if (this.TryAddToYieldReturningBlocks(V_1))
{
continue;
}
V_2 = false;
goto Label1;
}
else
{
if (StateMachineUtilities.IsUnconditionalBranch(V_1.get_Last()) && this.MarkPredecessorsAsYieldReturns(V_1))
{
continue;
}
V_2 = false;
goto Label1;
}
}
goto Label0;
}
finally
{
((IDisposable)V_0).Dispose();
}
Label1:
return(V_2);
Label0:
return(true);
}
private bool IsVisualBasicDebugCheck(InstructionBlock theBlock, Instruction currentInstruction)
{
if ((object)currentInstruction == (object)theBlock.get_Last() || !StateMachineUtilities.TryGetVariableFromInstruction(currentInstruction, this.methodVariables, out V_0))
{
return(false);
}
currentInstruction = currentInstruction.get_Next();
if ((object)currentInstruction == (object)theBlock.get_Last() || !StateMachineUtilities.TryGetVariableFromInstruction(currentInstruction, this.methodVariables, out V_1) || (object)V_0 != (object)V_1)
{
return(false);
}
currentInstruction = currentInstruction.get_Next();
if ((object)currentInstruction != (object)theBlock.get_Last())
{
return(false);
}
if (currentInstruction.get_OpCode().get_Code() == 56)
{
return(true);
}
return(currentInstruction.get_OpCode().get_Code() == 43);
}
/// <summary>
/// Checks whether the specified block is a controller block generated by the compiler in debug mode.
/// </summary>
/// <remarks>
/// Pattern:
///
/// ldfld stateField
/// ldc.i4.* stateNumber
/// ceq
/// ldc.i4.0
/// .....
/// brtrue* .....
/// </remarks>
/// <param name="theBlock"></param>
/// <param name="stateNumber"></param>
/// <returns></returns>
private bool IsDebugControllerBlock(InstructionBlock theBlock, out int stateNumber)
{
if (theBlock.First == theBlock.Last)
{
stateNumber = -1;
return(false);
}
Instruction currentInstruction = theBlock.First.Next;
if (currentInstruction == theBlock.Last || currentInstruction.OpCode.Code != Code.Ldfld ||
((FieldReference)currentInstruction.Operand).Resolve() != this.stateField)
{
stateNumber = -1;
return(false);
}
currentInstruction = currentInstruction.Next;
if (currentInstruction == theBlock.Last || !StateMachineUtilities.TryGetOperandOfLdc(currentInstruction, out stateNumber))
{
stateNumber = -1;
return(false);
}
currentInstruction = currentInstruction.Next;
if (currentInstruction == theBlock.Last || currentInstruction.OpCode.Code != Code.Ceq)
{
return(false);
}
currentInstruction = currentInstruction.Next;
if (currentInstruction == theBlock.Last || currentInstruction.OpCode.Code != Code.Ldc_I4_0)
{
return(false);
}
return(theBlock.Last.OpCode.Code == Code.Brtrue || theBlock.Last.OpCode.Code == Code.Brtrue_S);
}
/// <summary>
/// Checks whether the specified block ends as a do-finally-check block generated by the VB compiler in debug mode.
/// </summary>
/// <remarks>
/// Instead of:
/// brfalse* endfinally
///
/// stloc* someVariable
/// ldloc* someVariable
/// brfalse* endfinally
/// </remarks>
/// <param name="theBlock"></param>
/// <param name="currentInstruction"></param>
/// <returns></returns>
private bool IsVisualBasicDebugCheck(InstructionBlock theBlock, Instruction currentInstruction)
{
VariableReference storingVariable;
if (currentInstruction == theBlock.Last ||
!StateMachineUtilities.TryGetVariableFromInstruction(currentInstruction, methodVariables, out storingVariable))
{
return(false);
}
currentInstruction = currentInstruction.Next;
VariableReference loadingVariable;
if (currentInstruction == theBlock.Last ||
!StateMachineUtilities.TryGetVariableFromInstruction(currentInstruction, methodVariables, out loadingVariable) ||
storingVariable != loadingVariable)
{
return(false);
}
currentInstruction = currentInstruction.Next;
return(currentInstruction == theBlock.Last && (currentInstruction.OpCode.Code == Code.Brfalse || currentInstruction.OpCode.Code == Code.Brfalse_S));
}
private bool IsFinallyMethodInvocationBlock(InstructionBlock block)
{
V_0 = block.get_First();
if (V_0.get_OpCode().get_Code() != 2)
{
return(false);
}
V_0 = V_0.get_Next();
if (V_0.get_OpCode().get_Code() != 39)
{
return(false);
}
V_1 = V_0;
V_0 = V_0.get_Next();
if (V_0.get_OpCode().get_Code() == null)
{
V_0 = V_0.get_Next();
}
if (!StateMachineUtilities.IsUnconditionalBranch(V_0))
{
return(false);
}
if ((object)block.get_Last() != (object)V_0)
{
return(false);
}
V_2 = V_1.get_Operand() as MethodReference;
if (V_2 == null)
{
return(false);
}
if (!V_2.get_Name().StartsWith("<>m__Finally"))
{
return(false);
}
return(true);
}
private bool IsDebugControllerBlock(InstructionBlock theBlock, out int stateNumber)
{
if ((object)theBlock.get_First() == (object)theBlock.get_Last())
{
stateNumber = -1;
return(false);
}
V_0 = theBlock.get_First().get_Next();
if ((object)V_0 == (object)theBlock.get_Last() || V_0.get_OpCode().get_Code() != 120 || (object)((FieldReference)V_0.get_Operand()).Resolve() != (object)this.stateField)
{
stateNumber = -1;
return(false);
}
V_0 = V_0.get_Next();
if ((object)V_0 == (object)theBlock.get_Last() || !StateMachineUtilities.TryGetOperandOfLdc(V_0, out stateNumber))
{
stateNumber = -1;
return(false);
}
V_0 = V_0.get_Next();
if ((object)V_0 == (object)theBlock.get_Last() || V_0.get_OpCode().get_Code() != 192)
{
return(false);
}
V_0 = V_0.get_Next();
if ((object)V_0 == (object)theBlock.get_Last() || V_0.get_OpCode().get_Code() != 22)
{
return(false);
}
if (theBlock.get_Last().get_OpCode().get_Code() == 57)
{
return(true);
}
V_1 = theBlock.get_Last().get_OpCode();
return(V_1.get_Code() == 44);
}
private YieldStateMachineControlFlowRebuilder.NextStateNumberSearchResult TryGetNextStateNumber(InstructionBlock theBlock, out int newStateNumber)
{
V_0 = theBlock.get_Last();
while ((object)V_0 != (object)theBlock.get_First())
{
if (V_0.get_OpCode().get_Code() == 122 && (object)this.stateField == (object)((FieldReference)V_0.get_Operand()).Resolve())
{
V_0 = V_0.get_Previous();
if (!StateMachineUtilities.TryGetOperandOfLdc(V_0, out newStateNumber))
{
return(0);
}
V_0 = V_0.get_Previous().get_Previous();
if (V_0.get_OpCode().get_Code() == 122 && this.CheckAndSaveCurrentItemField((FieldReference)V_0.get_Operand()))
{
return(1);
}
return(0);
}
V_0 = V_0.get_Previous();
}
newStateNumber = 0;
return(2);
}