/// <summary>
/// Returns true if a ValueNode graph contains a cycle
/// </summary>
/// <param name="node">Node to evaluate</param>
/// <param name="seenNodes">Set of nodes previously seen on the current arc. Callers may pass a non-empty set
/// to test whether adding that set to this node would create a cycle. Contents will be modified by the walk
/// and should not be used by the caller after returning</param>
/// <param name="allNodesSeen">Optional. The set of all nodes encountered during a walk after DetectCycle returns</param>
/// <returns></returns>
public static bool DetectCycle(this ValueNode node, HashSet <ValueNode> seenNodes, HashSet <ValueNode> allNodesSeen)
{
if (node == null)
{
return(false);
}
if (seenNodes.Contains(node))
{
return(true);
}
seenNodes.Add(node);
if (allNodesSeen != null)
{
allNodesSeen.Add(node);
}
bool foundCycle = false;
switch (node.Kind)
{
//
// Leaf nodes
//
case ValueNodeKind.Unknown:
case ValueNodeKind.Null:
case ValueNodeKind.SystemType:
case ValueNodeKind.RuntimeTypeHandle:
case ValueNodeKind.KnownString:
case ValueNodeKind.AnnotatedString:
case ValueNodeKind.ConstInt:
case ValueNodeKind.MethodParameter:
case ValueNodeKind.MethodReturn:
case ValueNodeKind.SystemTypeForGenericParameter:
case ValueNodeKind.RuntimeTypeHandleForGenericParameter:
case ValueNodeKind.LoadField:
break;
//
// Nodes with children
//
case ValueNodeKind.MergePoint:
foreach (ValueNode val in ((MergePointValue)node).Values)
{
if (val.DetectCycle(seenNodes, allNodesSeen))
{
foundCycle = true;
}
}
break;
case ValueNodeKind.GetTypeFromString:
GetTypeFromStringValue gtfsv = (GetTypeFromStringValue)node;
foundCycle = gtfsv.AssemblyIdentity.DetectCycle(seenNodes, allNodesSeen);
foundCycle |= gtfsv.NameString.DetectCycle(seenNodes, allNodesSeen);
break;
case ValueNodeKind.Array:
ArrayValue av = (ArrayValue)node;
foundCycle = av.Size.DetectCycle(seenNodes, allNodesSeen);
break;
default:
throw new Exception(String.Format("Unknown node kind: {0}", node.Kind));
}
seenNodes.Remove(node);
return(foundCycle);
}
public GetTypeFromStringValue(TypeResolver resolver, ValueNode assemblyIdentity, ValueNode nameString)
{
_resolver = resolver;
Kind = ValueNodeKind.GetTypeFromString;
AssemblyIdentity = assemblyIdentity;
NameString = nameString;
}
/// <summary>
/// Constructs an array value of the given size
/// </summary>
public ArrayValue(ValueNode size)
{
Kind = ValueNodeKind.Array;
Size = size ?? UnknownValue.Instance;
}
protected virtual void HandleStoreParameter(MethodDefinition method, int index, Instruction operation, ValueNode valueToStore)
{
}
protected virtual void HandleStoreField(MethodDefinition method, FieldDefinition field, Instruction operation, ValueNode valueToStore)
{
}
public StackSlot(ValueNode value, bool isByRef = false)
{
Value = value;
IsByRef = isByRef;
}
public void Scan(MethodBody methodBody)
{
MethodDefinition thisMethod = methodBody.Method;
Dictionary <VariableDefinition, ValueBasicBlockPair> locals = new Dictionary <VariableDefinition, ValueBasicBlockPair> (methodBody.Variables.Count);
Dictionary <int, Stack <StackSlot> > knownStacks = new Dictionary <int, Stack <StackSlot> > ();
Stack <StackSlot> currentStack = new Stack <StackSlot> (methodBody.MaxStackSize);
ScanExceptionInformation(knownStacks, methodBody);
BasicBlockIterator blockIterator = new BasicBlockIterator(methodBody);
MethodReturnValue = null;
foreach (Instruction operation in methodBody.Instructions)
{
int curBasicBlock = blockIterator.MoveNext(operation);
if (knownStacks.ContainsKey(operation.Offset))
{
if (currentStack == null)
{
// The stack copy constructor reverses the stack
currentStack = new Stack <StackSlot> (knownStacks[operation.Offset].Reverse());
}
else
{
currentStack = MergeStack(currentStack, knownStacks[operation.Offset]);
}
}
if (currentStack == null)
{
currentStack = new Stack <StackSlot> (methodBody.MaxStackSize);
}
switch (operation.OpCode.Code)
{
case Code.Add:
case Code.Add_Ovf:
case Code.Add_Ovf_Un:
case Code.And:
case Code.Div:
case Code.Div_Un:
case Code.Mul:
case Code.Mul_Ovf:
case Code.Mul_Ovf_Un:
case Code.Or:
case Code.Rem:
case Code.Rem_Un:
case Code.Sub:
case Code.Sub_Ovf:
case Code.Sub_Ovf_Un:
case Code.Xor:
case Code.Cgt:
case Code.Cgt_Un:
case Code.Clt:
case Code.Clt_Un:
case Code.Shl:
case Code.Shr:
case Code.Shr_Un:
case Code.Ceq:
PopUnknown(currentStack, 2, methodBody, operation.Offset);
PushUnknown(currentStack);
break;
case Code.Dup:
currentStack.Push(currentStack.Peek());
break;
case Code.Ldnull:
currentStack.Push(new StackSlot(NullValue.Instance));
break;
case Code.Ldc_I4_0:
case Code.Ldc_I4_1:
case Code.Ldc_I4_2:
case Code.Ldc_I4_3:
case Code.Ldc_I4_4:
case Code.Ldc_I4_5:
case Code.Ldc_I4_6:
case Code.Ldc_I4_7:
case Code.Ldc_I4_8: {
int value = operation.OpCode.Code - Code.Ldc_I4_0;
ConstIntValue civ = new ConstIntValue(value);
StackSlot slot = new StackSlot(civ);
currentStack.Push(slot);
}
break;
case Code.Ldc_I4_M1: {
ConstIntValue civ = new ConstIntValue(-1);
StackSlot slot = new StackSlot(civ);
currentStack.Push(slot);
}
break;
case Code.Ldc_I4: {
int value = (int)operation.Operand;
ConstIntValue civ = new ConstIntValue(value);
StackSlot slot = new StackSlot(civ);
currentStack.Push(slot);
}
break;
case Code.Ldc_I4_S: {
int value = (sbyte)operation.Operand;
ConstIntValue civ = new ConstIntValue(value);
StackSlot slot = new StackSlot(civ);
currentStack.Push(slot);
}
break;
case Code.Arglist:
case Code.Ldftn:
case Code.Sizeof:
case Code.Ldc_I8:
case Code.Ldc_R4:
case Code.Ldc_R8:
PushUnknown(currentStack);
break;
case Code.Ldarg:
case Code.Ldarg_0:
case Code.Ldarg_1:
case Code.Ldarg_2:
case Code.Ldarg_3:
case Code.Ldarg_S:
case Code.Ldarga:
case Code.Ldarga_S:
ScanLdarg(operation, currentStack, thisMethod, methodBody);
break;
case Code.Ldloc:
case Code.Ldloc_0:
case Code.Ldloc_1:
case Code.Ldloc_2:
case Code.Ldloc_3:
case Code.Ldloc_S:
case Code.Ldloca:
case Code.Ldloca_S:
ScanLdloc(operation, currentStack, methodBody, locals);
break;
case Code.Ldstr: {
StackSlot slot = new StackSlot(new KnownStringValue((string)operation.Operand));
currentStack.Push(slot);
}
break;
case Code.Ldtoken:
ScanLdtoken(operation, currentStack);
break;
case Code.Ldind_I:
case Code.Ldind_I1:
case Code.Ldind_I2:
case Code.Ldind_I4:
case Code.Ldind_I8:
case Code.Ldind_R4:
case Code.Ldind_R8:
case Code.Ldind_U1:
case Code.Ldind_U2:
case Code.Ldind_U4:
case Code.Ldlen:
case Code.Ldvirtftn:
case Code.Localloc:
case Code.Refanytype:
case Code.Refanyval:
case Code.Conv_I1:
case Code.Conv_I2:
case Code.Conv_I4:
case Code.Conv_Ovf_I1:
case Code.Conv_Ovf_I1_Un:
case Code.Conv_Ovf_I2:
case Code.Conv_Ovf_I2_Un:
case Code.Conv_Ovf_I4:
case Code.Conv_Ovf_I4_Un:
case Code.Conv_Ovf_U:
case Code.Conv_Ovf_U_Un:
case Code.Conv_Ovf_U1:
case Code.Conv_Ovf_U1_Un:
case Code.Conv_Ovf_U2:
case Code.Conv_Ovf_U2_Un:
case Code.Conv_Ovf_U4:
case Code.Conv_Ovf_U4_Un:
case Code.Conv_U1:
case Code.Conv_U2:
case Code.Conv_U4:
case Code.Conv_I8:
case Code.Conv_Ovf_I8:
case Code.Conv_Ovf_I8_Un:
case Code.Conv_Ovf_U8:
case Code.Conv_Ovf_U8_Un:
case Code.Conv_U8:
case Code.Conv_I:
case Code.Conv_Ovf_I:
case Code.Conv_Ovf_I_Un:
case Code.Conv_U:
case Code.Conv_R_Un:
case Code.Conv_R4:
case Code.Conv_R8:
case Code.Ldind_Ref:
case Code.Ldobj:
case Code.Mkrefany:
case Code.Unbox:
case Code.Unbox_Any:
case Code.Box:
case Code.Neg:
case Code.Not:
PopUnknown(currentStack, 1, methodBody, operation.Offset);
PushUnknown(currentStack);
break;
case Code.Isinst:
case Code.Castclass:
// We can consider a NOP because the value doesn't change.
// It might change to NULL, but for the purposes of dataflow analysis
// it doesn't hurt much.
break;
case Code.Ldfld:
case Code.Ldsfld:
case Code.Ldflda:
case Code.Ldsflda:
ScanLdfld(operation, currentStack, thisMethod, methodBody);
break;
case Code.Newarr: {
StackSlot count = PopUnknown(currentStack, 1, methodBody, operation.Offset);
currentStack.Push(new StackSlot(new ArrayValue(count.Value, (TypeReference)operation.Operand)));
}
break;
case Code.Stelem_I:
case Code.Stelem_I1:
case Code.Stelem_I2:
case Code.Stelem_I4:
case Code.Stelem_I8:
case Code.Stelem_R4:
case Code.Stelem_R8:
case Code.Stelem_Any:
case Code.Stelem_Ref:
ScanStelem(operation, currentStack, methodBody, curBasicBlock);
break;
case Code.Ldelem_I:
case Code.Ldelem_I1:
case Code.Ldelem_I2:
case Code.Ldelem_I4:
case Code.Ldelem_I8:
case Code.Ldelem_R4:
case Code.Ldelem_R8:
case Code.Ldelem_U1:
case Code.Ldelem_U2:
case Code.Ldelem_U4:
case Code.Ldelem_Any:
case Code.Ldelem_Ref:
case Code.Ldelema:
ScanLdelem(operation, currentStack, methodBody, curBasicBlock);
break;
case Code.Cpblk:
case Code.Initblk:
PopUnknown(currentStack, 3, methodBody, operation.Offset);
break;
case Code.Stfld:
case Code.Stsfld:
ScanStfld(operation, currentStack, thisMethod, methodBody);
break;
case Code.Cpobj:
PopUnknown(currentStack, 2, methodBody, operation.Offset);
break;
case Code.Stind_I:
case Code.Stind_I1:
case Code.Stind_I2:
case Code.Stind_I4:
case Code.Stind_I8:
case Code.Stind_R4:
case Code.Stind_R8:
case Code.Stind_Ref:
case Code.Stobj:
ScanIndirectStore(operation, currentStack, methodBody);
break;
case Code.Initobj:
case Code.Pop:
PopUnknown(currentStack, 1, methodBody, operation.Offset);
break;
case Code.Starg:
case Code.Starg_S:
ScanStarg(operation, currentStack, thisMethod, methodBody);
break;
case Code.Stloc:
case Code.Stloc_S:
case Code.Stloc_0:
case Code.Stloc_1:
case Code.Stloc_2:
case Code.Stloc_3:
ScanStloc(operation, currentStack, methodBody, locals, curBasicBlock);
break;
case Code.Constrained:
case Code.No:
case Code.Readonly:
case Code.Tail:
case Code.Unaligned:
case Code.Volatile:
break;
case Code.Brfalse:
case Code.Brfalse_S:
case Code.Brtrue:
case Code.Brtrue_S:
PopUnknown(currentStack, 1, methodBody, operation.Offset);
NewKnownStack(knownStacks, ((Instruction)operation.Operand).Offset, currentStack);
break;
case Code.Calli: {
var signature = (CallSite)operation.Operand;
if (signature.HasThis && !signature.ExplicitThis)
{
PopUnknown(currentStack, 1, methodBody, operation.Offset);
}
// Pop arguments
PopUnknown(currentStack, signature.Parameters.Count, methodBody, operation.Offset);
// Pop function pointer
PopUnknown(currentStack, 1, methodBody, operation.Offset);
// Push return value
if (signature.ReturnType.MetadataType != MetadataType.Void)
{
PushUnknown(currentStack);
}
}
break;
case Code.Call:
case Code.Callvirt:
case Code.Newobj:
HandleCall(methodBody, operation, currentStack, curBasicBlock);
break;
case Code.Jmp:
// Not generated by mainstream compilers
break;
case Code.Br:
case Code.Br_S:
NewKnownStack(knownStacks, ((Instruction)operation.Operand).Offset, currentStack);
ClearStack(ref currentStack);
break;
case Code.Leave:
case Code.Leave_S:
ClearStack(ref currentStack);
NewKnownStack(knownStacks, ((Instruction)operation.Operand).Offset, new Stack <StackSlot> (methodBody.MaxStackSize));
break;
case Code.Endfilter:
case Code.Endfinally:
case Code.Rethrow:
case Code.Throw:
ClearStack(ref currentStack);
break;
case Code.Ret: {
bool hasReturnValue = methodBody.Method.ReturnType.MetadataType != MetadataType.Void;
if (currentStack.Count != (hasReturnValue ? 1 : 0))
{
WarnAboutInvalidILInMethod(methodBody, operation.Offset);
}
if (hasReturnValue)
{
StackSlot retValue = PopUnknown(currentStack, 1, methodBody, operation.Offset);
MethodReturnValue = MergePointValue.MergeValues(MethodReturnValue, retValue.Value);
}
ClearStack(ref currentStack);
break;
}
case Code.Switch: {
PopUnknown(currentStack, 1, methodBody, operation.Offset);
Instruction[] targets = (Instruction[])operation.Operand;
foreach (Instruction target in targets)
{
NewKnownStack(knownStacks, target.Offset, currentStack);
}
break;
}
case Code.Beq:
case Code.Beq_S:
case Code.Bne_Un:
case Code.Bne_Un_S:
case Code.Bge:
case Code.Bge_S:
case Code.Bge_Un:
case Code.Bge_Un_S:
case Code.Bgt:
case Code.Bgt_S:
case Code.Bgt_Un:
case Code.Bgt_Un_S:
case Code.Ble:
case Code.Ble_S:
case Code.Ble_Un:
case Code.Ble_Un_S:
case Code.Blt:
case Code.Blt_S:
case Code.Blt_Un:
case Code.Blt_Un_S:
PopUnknown(currentStack, 2, methodBody, operation.Offset);
NewKnownStack(knownStacks, ((Instruction)operation.Operand).Offset, currentStack);
break;
}
}
}
public abstract bool HandleCall(
MethodBody callingMethodBody,
MethodReference calledMethod,
Instruction operation,
ValueNodeList methodParams,
out ValueNode methodReturnValue);